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Sample records for liquid xenon ionization

  1. A liquid xenon ionization chamber in an all-fluoropolymer vessel

    CERN Document Server

    LePort, F; Baussan, E; Breidenbach, M; Conley, R; DeVoe, R; Diez, M M; Fairbank, W; Farine, J; Fierlinger, P; Flatt, B; Gratta, G; Green, M; Hall, C; Hall, K; Hallman, D; Hargrove, C K; Hodgson, J; Jeng, S; Koffas, T; Leonard, D S; Mackay, D; Martin, Y; Neilson, R; O'Sullivan, K; Odian, A; Ounalli, L; Piepke, A; Pocar, A; Prescott, C Y; Rowson, P C; Schenker, D; Sinclair, D; Skarpaas, K V; Stekhanov, V; Strickland, V; Virtue, C; Vuilleumier, J L; Vuilleumier, J M; Waldman, S J; Wamba, K; Weber, P; Wodin, J; Woisard, D

    2006-01-01

    A novel technique has been developed to build vessels for liquid xenon ionization detectors entirely out of ultra-clean fluoropolymer. We describe the advantages in terms of low radioactivity contamination, provide some details of the construction techniques, and show the energy resolution achieved with a prototype all-fluoropolymer ionization detector.

  2. A Liquid Xenon Ionization Chamber in an All-fluoropolymer Vessel

    Energy Technology Data Exchange (ETDEWEB)

    LePort, F.; Pocar, A.; Bartoszek, L.; DeVoe, R.; Fierlinger, P.; Flatt, B.; Gratta, G.; Green, M.; Montero Diez, M.; Neilson, R.; O' Sullivan, K.; Wodin, J.; Woisard, D.; Baussan, E.; Breidenbach, M.; Conley, R.; Fairbank, W., Jr.; Farine, J.; Hall, K.; Hallman, D.; Hargrove, C.; /Stanford U., Phys. Dept. /Applied Plastics Technology, Bristol

    2007-02-26

    A novel technique has been developed to build vessels for liquid xenon ionization detectors entirely out of ultra-clean fluoropolymer. We describe the advantages in terms of low radioactivity contamination, provide some details of the construction techniques, and show the energy resolution achieved with a prototype all-fluoropolymer ionization detector.

  3. Performance of a Large Area Avalanche Photodiode in a Liquid Xenon Ionization and Scintillation Chamber

    CERN Document Server

    Ni, K; Day, D; Giboni, K L; Lopes, J A M; Majewski, P; Yamashita, M

    2005-01-01

    Scintillation light produced in liquid xenon (LXe) by alpha particles, electrons and gamma-rays was detected with a large area avalanche photodiode (LAAPD) immersed in the liquid. The alpha scintillation yield was measured as a function of applied electric field. We estimate the quantum efficiency of the LAAPD to be 45%. The best energy resolution from the light measurement at zero electric field is 7.5%(sigma) for 976 keV internal conversion electrons from Bi-207 and 2.6%(sigma) for 5.5 MeV alpha particles from Am-241. The detector used for these measurements was also operated as a gridded ionization chamber to measure the charge yield. We confirm that using a LAAPD in LXe does not introduce impurities which inhibit the drifting of free electrons.

  4. Wimp Detection Using Liquid Xenon (dark Matter)

    CERN Document Server

    Wang, H

    1998-01-01

    The missing mass "Dark Matter" problem of the Universe is one of the most important questions facing the moden physics and astronomy. This thesis work developed the Liquid Xenon technology to detect the SUSY ark matter. The background rejection principle was tested and many technical problem are studied, including the purification of the liquid xenon to yield both long electron lifetime and long xenon scintillation light attenuation length, and xenon recoil scintillation efficiency measurement. The detector design and construction are studied. Finally a two phase xenon detector was realized for the future dark matter experiment. The key working principle is the use of proportional scintillation and electro-luminescence to detector the ionization components, which is different between background and recoil signals. The two phase test results shown that a detector energy threshold as low as 10keV can be achieved.

  5. Simultaneous reconstruction of scintillation light and ionization charge produced by 511 keV photons in liquid xenon: Potential application to PET

    Energy Technology Data Exchange (ETDEWEB)

    Amaudruz, P. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: amaudruz@triumf.ca; Bryman, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)], E-mail: bryman@phas.ubc.ca; Kurchaninov, L. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: kurchan@triumf.ca; Lu, P. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)], E-mail: philipfl@phas.ubc.ca; Marshall, C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: cammarsh@triumf.ca; Martin, J.P. [University of Montreal, CP 6128 Succursale Centre-Ville, Montreal, Quebec, H3C 3J7 (Canada)], E-mail: jpmartin@lps.umontreal.ca; Muennich, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: muennich@triumf.ca; Retiere, F. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: fretiere@triumf.ca; Sher, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada)], E-mail: sher@triumf.ca

    2009-08-21

    In order to assess the performance of liquid xenon detectors for use in positron emission tomography we studied the scintillation light and ionization charge produced by 511 keV photons in a small prototype detector. Scintillation light was detected with large area avalanche photodiodes while ionization electrons were collected on an anode instrumented with low noise electronics after drifting up to 3 cm. Operational conditions were studied as a function of the electric field. Energy resolutions of <10% (FWHM) were achieved by combining the scintillation light and ionization charge signals. The relationship between scintillation light and ionization signals was investigated. An analysis of the sources of fluctuations was performed in order to optimize future detector designs.

  6. Detection of gamma-rays with a 3.5 l liquid xenon ionization chamber triggered by the primary scintillation light

    CERN Document Server

    Aprile, E; Chen Dan Li; Muhkerjee, R; Xu Fan

    2002-01-01

    A gridded ionization chamber with a drift length of 4.5 cm and a total volume of 3.5 l, was operated with high-purity liquid xenon and extensively tested with gamma-rays from sup 1 sup 3 sup 7 Cs, sup 2 sup 2 Na and sup 6 sup 0 Co radioactive sources. An electron lifetime in excess of 1 ms was inferred from two independent measurements. The electric field dependence of the collected charge and energy resolution was studied in the range 0.1-4 kV/cm, for different gamma-ray energies. With an electric field of 4 kV/cm, the spectral performance of the detector is consistent with an energy resolution of 5.9% at 1 MeV, scaling with energy as E sup - sup 0 sup . sup 5. The chamber was also used to detect the primary scintillation light produced by gamma-ray interactions in liquid xenon. The light signal was successfully used to trigger the acquisition of the charge signal with a FADC readout. A trigger efficiency of approx 85% was measured at 662 keV.

  7. Liquid Xenon Detectors for Positron Emission Tomography

    CERN Document Server

    Miceli, A; Benard, F; Bryman, D A; Kurchaninov, L; Martin, J P; Muennich, A; Retiere, F; Ruth, T J; Sossi, V; Stoessl, A J

    2011-01-01

    PET is a functional imaging technique based on detection of annihilation photons following beta decay producing positrons. In this paper, we present the concept of a new PET system for preclinical applications consisting of a ring of twelve time projection chambers filled with liquid xenon viewed by avalanche photodiodes. Simultaneous measurement of ionization charge and scintillation light leads to a significant improvement to spatial resolution, image quality, and sensitivity. Simulated performance shows that an energy resolution of <10% (FWHM) and a sensitivity of 15% are achievable. First tests with a prototype TPC indicate position resolution <1 mm (FWHM).

  8. Direct observation of bubble-assisted electroluminescence in liquid xenon

    CERN Document Server

    Erdal, E; Chepel, V; Rappaport, M L; Vartsky, D; Breskin, A

    2015-01-01

    Bubble formation in liquid xenon underneath a Thick Gaseous Electron Multiplier (THGEM) electrode immersed in liquid xenon was observed with a CCD camera. With voltage across the THGEM, the appearance of bubbles was correlated with that of electroluminescence signals induced by ionization electrons from alpha-particle tracks. This confirms recent indirect evidence that the observed photons are due to electroluminescence within a xenon vapor layer trapped under the electrode. The bubbles seem to emerge spontaneously due to heat flow from 300K into the liquid, or in a controlled manner, by locally boiling the liquid with resistive wires. Controlled bubble formation resulted in energy resolution of {\\sigma}/E~7.5% for ~6,000 ionization electrons. The phenomenon could pave ways towards the conception of large-volume 'local dual-phase' noble-liquid TPCs.

  9. MPGDs in Compton imaging with liquid-xenon

    CERN Document Server

    Samuel, Duval; Herve, Carduner; Jean-Pierre, Cussonneau; Jacob, Lamblin; Patrick, Le Ray; Eric, Morteau; Tugdual, Oger; Jean-Sebastien, Stutzmann; Dominique, Thers

    2009-01-01

    The interaction of radiation with liquid xenon, inducing both scintillation and ionization signals, is of particular interest for Compton-sequences reconstruction. We report on the development and recent results of a liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging technique named "3 gamma imaging". In a first prototype, the scintillation is detected by a vacuum photomultiplier tube and the charges are collected with a MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the final large-area detector, and with the aim of minimizing dead-zones, we are investigating a gaseous photomultiplier for recording the UV scintillation photons. The prototype concept is presented as well as preliminary results in liquid xenon. We also present soft x-rays test results of a gaseous photomultiplier prototype made of a double Thick Gaseous Electron Multiplier (THGEM) at normal temperature and pressure conditions.

  10. Calibration of a Liquid Xenon Detector with Kr-83m

    CERN Document Server

    Kastens, L W; Manzur, A; McKinsey, D N

    2009-01-01

    We report the preparation of a Kr-83m source and its subsequent use in calibrating a liquid xenon detector. Kr-83m atoms were produced through the decay of Rb-83 atoms trapped in zeolite molecular sieve and were then introduced into liquid xenon. Decaying Kr-83m nuclei were detected through liquid xenon scintillation. Conversion electrons with energies of 9.4 keV and 32.1 keV from the decay of Kr-83m were both observed. This calibration source will allow the characterization of the scintillation and ionization response of noble liquid detectors at low energies, highly valuable for the search for WIMP dark matter. Kr-83m may also be useful for measuring fluid flow dynamics, both to understand purification in noble liquid-based particle detectors, as well as for studies of classical and quantum turbulence in superfluid helium.

  11. Relative scintillation efficiency of liquid xenon in the XENON10 direct dark matter search

    Science.gov (United States)

    Manzur, Angel

    There is almost universal agreement that most of the mass in the Universe consists of dark matter. Many lines of reasoning suggest that the dark matter consists of a weakly interactive massive particle (WIMP) with mass ranging from 10 GeV/c 2 to a few TeV/c 2 . Today, numerous experiments aim for direct or indirect dark matter detection. XENON10 is a direct detection experiment using a xenon dual phase time projection chamber. Particles interacting with xenon will create a scintillation signal ( S 1) and ionization. The charge produced is extracted into the gas phase and converted into a proportional scintillation light ( S 2), with an external electric field. The dominant background, b particles and g rays, will undergo an electron recoil (ER) interaction, while WIMPs and neutrons will undergo a nuclear recoil (NR) interaction. Event-by-event discrimination of background signals is based on log 10 ( S 2/ S 1) NR review the requirements for a dark matter search. In particular I discuss the XENON10 detector, deployment, operation, calibrations, analysis and WIMP-nucleon cross- section limits. Finally, I present our latest results for the relative scintillation efficiency ([Special characters omitted.] ) for nuclear recoils in liquid xenon, which was the biggest source of uncertainty in the XENON10 limit. This quantity is essential to determine the nuclear energy scale and to determine the WIMP-nucleon cross sections.

  12. Ionization and scintillation of nuclear recoils in gaseous xenon

    Energy Technology Data Exchange (ETDEWEB)

    Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

    2015-09-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope α-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  13. Ionization and scintillation of nuclear recoils in gaseous xenon

    CERN Document Server

    Renner, J; Goldschmidt, A; Matis, H S; Miller, T; Nakajima, Y; Nygren, D; Oliveira, C A B; Shuman, D; Álvarez, V; Borges, F I G; Cárcel, S; Castel, J; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Dias, T H V T; Díaz, J; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Gil, A; Gómez, H; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Iguaz, F J; Irastorza, I G; Jinete, M A; Labarga, L; Laing, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Martínez, A; Moiseenko, A; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; da Luz, H Natal; Navarro, G; Nebot-Guinot, M; Palma, R; Pérez, J; Aparicio, J L Pérez; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Seguí, L; Serra, L; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Tomás, A; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Villar, J A; Webb, R C; White, J; Yahlali, N

    2014-01-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope $\\alpha$-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  14. Liquid xenon purification, de-radonation (and de-kryptonation)

    Energy Technology Data Exchange (ETDEWEB)

    Pocar, Andrea, E-mail: pocar@umass.edu [Amherst Center for Fundamental Interactions and Physics Department, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-08-17

    Liquid xenon detectors are at the forefront of rare event physics, including searches for neutrino-less double beta decay and WIMP dark matter. The xenon for these experiments needs to be purified from chemical impurities such as electronegative atoms and molecules, which absorb ionization electrons, and VUV (178 nm) scintillation light-absorbing chemical species. In addition, superb purification from radioactive impurities is required. Particularly challenging are radioactive noble isotopes ({sup 85}Kr,{sup 39,42}Ar,{sup 220,222}Rn). Radon is a particularly universal problem, due to the extended decay sequence of its daughters and its ubiquitous presence in detector materials. Purification and de-radonation of liquid xenon are addressed with particular focus on the experience gained with the EXO-200 neutrino-less double beta decay detector.

  15. XMASS experiment, dark matter search with liquid xenon detector

    Energy Technology Data Exchange (ETDEWEB)

    Minamino, Akihiro, E-mail: minamino@scphys.kyoto-u.ac.j [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan)

    2010-11-01

    The XMASS Collaboration is developing liquid xenon detector for the purpose of direct detection of dark matter in the universe. A prototype detector was developed at Kamioka Observatory to test the basic performance of single phase liquid xenon detector. With the detector, the physical properties of liquid xenon were measured, and the performance of vertex and energy reconstruction and the self-shielding power of liquid xenon for background {gamma}-rays were confirmed.

  16. Absolute Electron Extraction Efficiency of Liquid Xenon

    Science.gov (United States)

    Kamdin, Katayun; Mizrachi, Eli; Morad, James; Sorensen, Peter

    2016-03-01

    Dual phase liquid/gas xenon time projection chambers (TPCs) currently set the world's most sensitive limits on weakly interacting massive particles (WIMPs), a favored dark matter candidate. These detectors rely on extracting electrons from liquid xenon into gaseous xenon, where they produce proportional scintillation. The proportional scintillation from the extracted electrons serves to internally amplify the WIMP signal; even a single extracted electron is detectable. Credible dark matter searches can proceed with electron extraction efficiency (EEE) lower than 100%. However, electrons systematically left at the liquid/gas boundary are a concern. Possible effects include spontaneous single or multi-electron proportional scintillation signals in the gas, or charging of the liquid/gas interface or detector materials. Understanding EEE is consequently a serious concern for this class of rare event search detectors. Previous EEE measurements have mostly been relative, not absolute, assuming efficiency plateaus at 100%. I will present an absolute EEE measurement with a small liquid/gas xenon TPC test bed located at Lawrence Berkeley National Laboratory.

  17. Detector r&d proposal liquid xenon(krypton) calorimetry

    CERN Document Server

    Séguinot, Jacques; Ypsilantis, Thomas; Bosteels, Michel; Chesi, Enrico Guido; Gougas, Andreas; Passardi, Giorgio; Tischhauser, Johann; Zichichi, Antonino; Ferreira-Marques, R; Lopes, M I; Policarpo, Armando; Kostrikov, M E; Ostankov, A P; Zaitsev, A; Giomataris, Ioanis; CERN. Geneva. Detector Research and Development Committee

    1990-01-01

    A proposal is made for R&D support to investigate the ultimate resolution achievable in a totally active liquid Xenon (Krypton) electromagnetic calorimeter which should lead to the construction of a 100 (400) litre prototype. Detection of either ionization or scintillation gives excellent energy resolution (sigmaE/E le 1%/sqrtE) while ionization alone gives precise determination of the direction (order 1mr) and vertex origin (order 1mm) of a high energy photon or electron (E ge 25 GeV). Large surface area photocathodes have been developed which efficiently detect the fast scintillation signal.

  18. Scintillation light, ionization yield and scintillation decay times in high pressure xenon and xenon methane

    NARCIS (Netherlands)

    Pushkin, K. N.; Akimov, D. Y.; Burenkov, A. A.; Dmitrenko, V. V.; Kovalenko, A. G.; Lebedenko, V. N.; Kuznetsov, I. S.; Stekhanov, V. N.; Tezuka, C.; Ulin, S. E.; Uteshev, Z. M.; Vlasik, K. F.

    2007-01-01

    Scintillation light, ionization yield and scintillation decay times have been measured in xenon and in its mixture with a 0.05% concentration of methane as a function of the reduced electric field (E/N)-the ratio of the electric field strength to the number density of gas-at a pressure of 21 atm. Th

  19. Radon Removal from Liquid Xenon

    Energy Technology Data Exchange (ETDEWEB)

    Martens, Kai [IPMU, The University of Tokyo, 456 Higashi-Mozumi, Kamioka-cho, Hida-shi, Gifu 506-1205 (Japan)

    2012-08-15

    Efforts are underway in Kamioka to develop a new method to remove Rn directly from the liquid phase of Xe. The idea is based on the observation that in the electronic structure of liquid noble gases charges can get trapped on impurities, and the charged impurities then be drifted through the noble gas liquid. In the case of Rn drifting the impurity into a suitable storage volume is enough as it will decay.

  20. Equation of State for Shock Compressed Xenon in the Ionization Regime:ab Initio Study

    Institute of Scientific and Technical Information of China (English)

    王聪; 顾云军; 陈其峰; 贺贤土; 张平

    2012-01-01

    Quantum molecular dynamic (QMD) simulations have been applied to study the thermophysical properties of liquid xenon under dynamic compressions. The equation of state (EOS) obtained from QMD calculations are corrected according to Saha equation, and contributions from atomic ionization, which are of predominance in determining the EOS at high temperature and pressure, are considered. For the pressures below 160 GPa, the necessity in accounting for the atomic ionization has been demonstrated by the Hugoniot curve, which shows excellent agreement with previous experimental measurements, and three levels of ionization have been proved to be sufficient at this stage.

  1. Liquid Hole Multipliers: bubble-assisted electroluminescence in liquid xenon

    CERN Document Server

    Arazi, L; Coimbra, A E C; Rappaport, M L; Vartsky, D; Chepel, V; Breskin, A

    2015-01-01

    In this work we discuss the mechanism behind the large electroluminescence signals observed at relatively low electric fields in the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon. We present strong evidence that the scintillation light is generated in xenon bubbles trapped below the THGEM holes. The process is shown to be remarkably stable over months of operation, providing - under specific thermodynamic conditions - energy resolution similar to that of present dual-phase liquid xenon experiments. The observed mechanism may serve as the basis for the development of Liquid Hole Multipliers (LHMs), capable of producing local charge-induced electroluminescence signals in large-volume single-phase noble-liquid detectors for dark matter and neutrino physics experiments.

  2. Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, P; Dahl, C E

    2011-02-14

    We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al.. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well-described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.

  3. Noble Liquid (Xenon or Krypton) Totally Active Calorimetry

    CERN Multimedia

    2002-01-01

    Main Goals\\\\ \\\\ Determine ionization and scintillation yields in liquid Xenon (LXe) or Krypton.\\\\ \\\\ Determine the electron lifetime and photon mean free path in LXe or LKr. \\\\ \\\\ Determine energy resolution of LXe or LKr via ionization or scintillation.\\\\ \\\\ Determine correlation of fluctuations between ionization and scintillation. Summary of Results \\\\ \\\\ -~measured the electron lifetime in LXe, ($\\tau$~$>$~400 $\\mu$s).\\\\ \\\\ -~measured the energy to create an ionization electron in LXe, W=9.8 eV.\\\\ \\\\ -~measured the energy to create a LXe scintillation photon, W$ _{s} $~=~14.2~eV. \\\\ \\\\ -~measured the anticorrelation of scintillation and ionization yields. \\\\ \\\\ -~measured the energy resolution in LXe via ionization, $ sigma _{E} / $E=0.07\\%/$\\sqrt$E(GeV). \\\\ \\\\ -~measured resolution in LXe via scintillation $ sigma _{E} / $E=0.24\\%/$\\sqrt$E(GeV)+0.26\\%. \\\\ \\\\ -~measured electron drift velocity in LXe:~neat (2.5 mm/$\\mu$s), doped (4.4~mm/$\\mu$s). \\\\ \\\\ -~measured the photon mean free path in LXe vs $ lambd...

  4. A Xenon Condenser with a Remote Liquid Storage Vessel

    CERN Document Server

    Slutsky, S; Breuer, H; Dobi, A; Hall, C; Langford, T; Leonard, D; Kaufman, L J; Strickland, V; Voskanian, N

    2009-01-01

    We describe the design and operation of a system for xenon liquefaction in which the condenser is separated from the liquid storage vessel. The condenser is cooled by a pulse tube cryocooler, while the vessel is cooled only by the liquid xenon itself. This arrangement facilitates liquid particle detector research by allowing easy access to the upper and lower flanges of the vessel. We find that an external xenon gas pump is useful for increasing the rate at which cooling power is delivered to the vessel, and we present measurements of the power and efficiency of the apparatus.

  5. Liquid xenon scintillators for imaging of positron emitters.

    Science.gov (United States)

    Lavoie, L

    The current understanding of xenon scintillation physics is summarized and keyed to the use of xenon as a gamma-ray detector in medical radioisotope imaging systems. Liquid xenon has a short scintillation pulse (approximately 10(8) sec) and high gamma-ray absorption and scintillation efficiencies. The fast pulse may facilitate imaging in vivo distributions of hot positron sources and allow recovery of additional spatial information by time-of-flight techniques. We begin by describing our own study of the feasibility of making a practical positron scanning system, and consider the problems of scintillation decay time, linearity, efficiency, purity, and electricfield amplifcation. The prospects for a practical instrument are considered.

  6. Adhesion energy, surface traction and surface tension in liquid xenon

    Indian Academy of Sciences (India)

    B Mathew; G A Adebayo

    2011-12-01

    We calculated the adhesion energy, the surface traction and the surface energy of liquid xenon using molecular dynamics (MD) simulation. The value of the adhesion energy for liquid xenon at a reduced density of 0.630 was found to be 0.591 J/m2 and the surface traction has a peak at = 3.32 Å. It was observed that the attraction of the molecules in the liquid surface which produces a resistance to penetration decreases with temperature. This may be attributed to the greater average separation of molecules at higher temperature.

  7. Signal yields, energy resolution, and recombination fluctuations in liquid xenon

    CERN Document Server

    Akerib, D S; Araújo, H M; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Bramante, R; Brás, P; Byram, D; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Ihm, M; Jacobsen, R G; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Manalaysay, A; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O'Sullivan, K; Oliver-Mallory, K C; Palladino, K J; Pease, E K; Phelps, P; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solmaz, M; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W C; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Xu, J; Yazdani, K; Young, S K; Zhang, C

    2016-01-01

    This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon re- combination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2-16 keV with $^3$H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured...

  8. Signal yields, energy resolution, and recombination fluctuations in liquid xenon

    Science.gov (United States)

    Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bramante, R.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration

    2017-01-01

    This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon recombination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2 and 16 keV with 3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.

  9. X-ray detector for automatic exposure control using ionization chamber filled with xenon gas

    CERN Document Server

    Nakagawa, A; Yoshida, T

    2003-01-01

    This report refers to our newly developed X-ray detector for reliable automatic X-ray exposure control, which is to be widely used for X-ray diagnoses in various clinical fields. This new detector utilizes an ionization chamber filled with xenon gas, in contrast to conventional X-ray detectors which use ionization chambers filled with air. Use of xenon gas ensures higher sensitivity and thinner design of the detector. The xenon gas is completely sealed in the chamber, so that the influence of the changes in ambient environments is minimized. (author)

  10. Multiphoton ionization photoelectron spectroscopy of xenon: Experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Bajic, S.J.; Compton, R.N.; Tang, X.; L' Huiller, A.; Lambropoulos, P.

    1988-11-01

    Photoelectron energy and angular distributions for resonantly enhanced multiphoton ionization (REMPI) of xenon via the three-photon-allowed 7s(3/2)/sub 1//sup 0/ and 5d(3/2)/sub 1//sup 0/ states have been studied both experimentally and theoretically. The electron kinetic energy spectra give the probability of leaving Xe/sup +/ in either the /sup 2/P/sub 1/2/ or /sup 2/P/sub 3/2/ core. The measured branching ratio for leaving each ionic core is used to test the theoretical description of the REMPI process. Measurements of both the angular distributions and the (3+1) REMPI via the 5d state are adequately reproduced by multichannel quantum defect theory. However, measurements of angular distributions for the electrons resulting from (3+1) via the 7s(3/2)/sub 1//sup 0/ state into Xe/sup +/ /sup 2/P/sub 3/2/ (core preserving) or Xe/sup +/ /sup 2/P/sub 1/2/ (core changing) are in striking disagreement with theory. 1 ref., 2 figs.

  11. Distillation of Liquid Xenon to Remove Krypton

    CERN Document Server

    Abe, K; Iida, T; Ikeda, M; Kobayashi, K; Koshio, Y; Minamino, A; Miura, M; Moriyama, S; Nakahata, M; Nakajima, Y; Namba, T; Ogawa, H; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takeuchi, Y; Ueshima, K; Yamashita, M; Kaneyuki, K; Ebizuka, Y; Kikuchi, J; Ota, A; Suzuki, S; Takahashi, T; Hagiwara, H; Kamei, T; Miyamoto, K; Nagase, T; Nakamura, S; Ozaki, Y; Sato, T; Fukuda, Y; Sato, T; Nishijima, K; Sakurai, M; Maruyama, T; Motoki, D; Itow, Y; Ohsumi, H; Tasaka, S; Kim, S B; Kim, Y D; Lee, J I; Moon, S H; Urakawa, Y; Uchino, M; Kamioka, Y

    2008-01-01

    A high performance distillation system to remove krypton from xenon was constructed, and a purity level of Kr/Xe = $\\sim 3 \\times 10^{-12}$ was achieved. This development is crucial in facilitating high sensitivity low background experiments such as the search for dark matter in the universe.

  12. Scintillation yield of liquid xenon at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, K. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan)], E-mail: ueshima@suketto.icrr.u-tokyo.ac.jp; Abe, K.; Iida, T.; Ikeda, M.; Kobayashi, K.; Koshio, Y.; Minamino, A.; Miura, M.; Moriyama, S. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Nakahata, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Nakajima, Y.; Ogawa, H.; Sekiya, H.; Shiozawa, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Suzuki, Y. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Takeda, A.; Takeuchi, Y.; Yamashita, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Kaneyuki, K. [Research Center for Cosmic Neutrinos, Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Doke, T. [Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8555 (Japan)] (and others)

    2008-09-01

    The intensity of scintillation light emission from liquid xenon at room temperature was measured. The scintillation light yield at 1{sup 0}C was measured to be 0.64{+-}0.02 (stat.) {+-}0.06 (sys.) of that at -100{sup 0}C. Using the reported light yield at -100{sup 0}C (46 photons/keV), the measured light yield at 1{sup 0}C corresponds to 29 photons/keV. This result shows that liquid xenon scintillator provides high light yield even at room temperature.

  13. Ionization and scintillation response of high-pressure xenon gas to alpha particles

    CERN Document Server

    Álvarez, V; Cárcel, S; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Díaz, J; Egorov, M; Esteve, R; Evtoukhovitch, P; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Gehman, V M; Gil, A; Goldschmidt, A; Gómez, H; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Irastorza, I G; Jinete, M A; Labarga, L; Laing, A; Liubarsky, I; Lopes, J A M; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Miller, T; Moiseenko, A; Monrabal, F; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; da Luz, H Natal; Navarro, G; Nebot, M; Nygren, D; Oliveira, C A B; Palma, R; Pérez, J; Aparicio, J L Pérez; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Segui, L; Serra, L; Shuman, D; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Tomás, A; Torrent, J; Tsamalaidze, Z; Vázquez, D; Veloso, J F C A; Webb, R; White, J T; Yahlali, N

    2012-01-01

    High-pressure xenon gas is an attractive detection medium for a variety of applications in fundamental and applied physics. In this paper we study the transport properties of ionization electrons, and the mechanism of electron-ion recombination, in xenon gas at 10 bar pressure. For this purpose, we use a source of alpha particles in the NEXT-DEMO time projection chamber, the large scale prototype of the NEXT-100 neutrinoless double beta decay experiment, in three different drift electric field configurations. Our electron drift velocity and longitudinal diffusion results are similar to expectations based on available electron scattering cross sections on pure xenon, favoring low-diffusion models. In addition, two types of measurements addressing the connection between the ionization and scintillation yields were performed. On the one hand we observe, for the first time in xenon gas, large event-by-event correlated fluctuations between the ionization and scintillation signals, similarly to what has already bee...

  14. First demonstration of VUV-photon detection in liquid xenon with THGEM and GEM-based Liquid Hole Multipliers

    CERN Document Server

    Erdal, E; Rappaport, M; Shchemelinin, S; Vartsky, D; Breskin, A

    2016-01-01

    The bubble-assisted Liquid Hole-Multiplier (LHM) is a recently-introduced detection concept for noble-liquid time projection chambers. In this "local dual-phase" detection element, a gas bubble is supported underneath a perforated electrode (e.g., Thick Gas Electron Multiplier - THGEM, or Gas Electron Multiplier - GEM). Electrons drifting through the holes induce large electroluminescence signals as they pass into the bubble. In this work we report on recent results of THGEM and GEM electrodes coated with cesium iodide and immersed in liquid xenon, allowing - for the first time - the detection of primary VUV scintillation photons in addition to ionization electrons using LHMs.

  15. Barium Tagging in Liquid Xenon for the nEXO Experiment

    Science.gov (United States)

    Kravitz, Scott; nEXO Collaboration

    2016-09-01

    nEXO is a next-generation experiment designed to search for neutrinoless double beta decay of xenon-136 in a liquid xenon time projection chamber. Positive observation of this decay would determine the neutrino to be a MAJORANA particle, as well as measure the absolute neutrino mass scale. In order to greatly reduce background contributions to this search, the collaboration is developing several ``barium tagging'' techniques to recover and identify the decay daughter, barium-136. Barium tagging may be available for a second phase of nEXO operation, allowing for neutrino mass sensitivity beyond the inverted mass hierarchy. Tagging methods for this phase include barium-ion capture on a probe with identification by resonance ionization laser spectroscopy. Inclusion of an argon ion gun in this system allows for improved cleaning and preparation of the barium deposition substrate, with recent results reported in this presentation.

  16. Measurements of proportional scintillation in liquid xenon using thin wires

    CERN Document Server

    Aprile, E; Goetzke, L W; Fernandez, A J Melgarejo; Messina, M; Naganoma, J; Plante, G; Rizzo, A; Shagin, P; Wall, R

    2014-01-01

    Proportional scintillation in liquid xenon has a promising application in the field of direct dark matter detection, potentially allowing for simpler, more sensitive detectors. However, knowledge of the basic properties of the phenomenon as well as guidelines for its practical use are currently limited. We report here on measurements of proportional scintillation light emitted in liquid xenon around thin wires. The maximum proportional scintillation gain of $287^{+97}_{-75}$ photons per drift electron was obtained using 10 $\\mu$m diameter gold plated tungsten wire. The thresholds for electron multiplication and proportional scintillation are measured as $725^{+48}_{-139}$ and $412^{+10}_{-133}$ kV/cm, respectively. The threshold for proportional scintillation is in good agreement with a previously published result, while the electron multiplication threshold represents a novel measurement. A complete set of parameters for the practical use of the electron multiplication and proportional scintillation processe...

  17. Dark matter sensitivity of multi-ton liquid xenon detectors

    CERN Document Server

    Schumann, Marc; Bütikofer, Lukas; Kish, Alexander; Selvi, Marco

    2015-01-01

    We study the sensitivity of multi ton-scale time projection chambers using a liquid xenon target, e.g., the proposed DARWIN instrument, to spin-independent and spin-dependent WIMP-nucleon scattering interactions. Taking into account realistic backgrounds from the detector itself as well as from neutrinos, we examine the impact of exposure, energy threshold, background rejection efficiency and energy resolution on the dark matter sensitivity. With an exposure of 200 t x y and assuming detector parameters which have been already demonstrated experimentally, spin-independent cross sections as low as $2.5 \\times 10^{-49}$ cm$^2$ can be probed for WIMP masses around 40 GeV/$c^2$. Additional improvements in terms of background rejection and exposure will further increase the sensitivity, while the ultimate WIMP science reach will be limited by neutrinos scattering coherently off the xenon nuclei.

  18. Neutrino physics with multi-ton scale liquid xenon detectors

    CERN Document Server

    Baudis, L; Kish, A; Manalaysay, A; Undagoitia, T Marrodan; Schumann, M

    2014-01-01

    We study the sensitivity of large-scale xenon detectors to low-energy solar neutrinos, to coherent neutrino-nucleus scattering and to neutrinoless double beta decay. As a concrete example, we consider the xenon part of the proposed DARWIN (Dark Matter WIMP Search with Noble Liquids) experiment. We perform detailed Monte Carlo simulations of the expected backgrounds, considering realistic energy resolutions and thresholds in the detector. In a low-energy window of 2-30 keV, where the sensitivity to solar pp and 7-Be neutrinos is highest, an integrated pp-neutrino rate of 5900 events can be reached in a fiducial mass of 14 tons of natural xenon, after 5 years of data. The pp-neutrino flux could thus be measured with a statistical uncertainty around 1%, reaching the precision of solar model predictions. These low-energy solar neutrinos will be the limiting background to the dark matter search channel for WIMP-nucleon cross sections below ~2x10^-48 cm^2 and WIMP masses around 50 GeV, for an assumed 99.5% rejectio...

  19. Determination of Xenon in Air by a Pulse-discharge Helium Ionization Detector

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhan-ying; CHANG Yin-zhong; LIU Shu-jiang; ZHANG Hai-tao; WANG Shi-lian; LI Qi

    2012-01-01

    A pulse-discharge helium ionization detector(Valco,PD-D3-I) was used to measure xenon concentration in air.The dependences of the detector relative response on various gas chromatograph parameters were investigated.Based on the well prepared gas connections for the detector system and optimized gas ehromatography(GC) working conditions,the atmospheric xenon concentration could be measured by the cheap GC method with a detection level of 0.7×10-9(parts by volume).Moreover,the xenon concentration in the ground level air around our laboratory was measured with the result of 0.085 × 10-6(parts by volume) and RSD of 0.91%.

  20. Intensity-Resolved Above Threshold Ionization of Xenon with Short Laser Pulses

    CERN Document Server

    Hart, Nathan A; Kaya, Gamze; Kaya, Necati; Kolomenskii, Alexandre A; Schuessler, Hans A

    2014-01-01

    We present intensity-resolved above threshold ionization (ATI) spectra of xenon using an intensity scanning and deconvolution technique. Experimental data were obtained with laser pulses of 58 fs and central wavelength of 800 nm from a chirped-pulse amplifier. Applying a deconvolution algorithm, we obtained spectra that have higher contrast and are in excellent agreement with characteristic 2 $U_p$ and 10 $U_p$ cutoff energies contrary to that found for raw data. The retrieved electron ionization probability is consistent with the presence of a second electron from double ionization. This recovered ionization probability is confirmed with a calculation based on the PPT tunneling ionization model [Perelomov, Popov, and Terent'ev, Sov. Phys. JETP 23, 924 (1966)]. Thus, the measurements of photoelectron yields and the proposed deconvolution technique allowed retrieval of more accurate spectroscopic information from the ATI spectra and ionization probability features that are usually concealed by volume averaging...

  1. Scintillation efficiency of nuclear recoil in liquid xenon

    CERN Document Server

    Arneodo, F; Badertscher, A; Benetti, P; Bernardini, E; Bettini, A; Borio di Tigliole, A A; Brunetti, R; Bueno, A G; Calligarich, E; Campanelli, M; Carpanese, C; Cavalli, D; Cavanna, F; Cennini, P; Centro, Sandro; Cesana, A; Cline, D; De Mitri, I; Dolfini, R; Ferrari, A; Gigli-Berzolari, A; Matthey, C; Mauri, F; Mazza, D; Mazzone, L; Meng, G; Montanari, C; Nurzia, G; Otwinowski, S; Palamara, O; Pascoli, D; Pepato, Adriano; Petrera, S; Periale, L; Piano Mortari, G; Piazzoli, A; Picchi, P; Pietropaolo, F; Rancati, T; Rappoldi, A; Raselli, G L; Rebuzzi, D; Revol, Jean Pierre Charles; Rico, J; Rossella, M; Rossi, C; Rubbia, André; Rubbia, Carlo; Sala, P; Scannicchio, D A; Sergiampietri, F; Suzuki, S; Terrani, M; Tian, W; Ventura, Sandro; Vignoli, C; Wang, H; Woo, J; Xu, Z

    2000-01-01

    We present the results of a test done with a Liquid Xenon (LXe) detector for 'Dark Matter' search, exposed to a neutron beam to produce nuclear recoil events simulating those which would be generated by WIMP's elastic scattering. The aim of the experiment was to measure directly the scintillation efficiency of nuclear recoil. The nuclear recoil considered in the test was in the tens of keV range. The ratio of measured visible energy over the true recoil energy was evaluated to be about 20%, in good agreement with the theoretical predictions.

  2. Development of Liquid Xenon Imaging Gamma-Ray Spectrophotometers

    Science.gov (United States)

    1990-07-01

    ground potential. The cathode plane is made from 63/rm diameter silver-plated beryllium copper wire set at 0.55mm pitch on a 15cm span. These wires are...100000 ( ! IUD i 10 10000 .. SCUID GAS Pressure Density (torr) 10 ,..........I (gm/cc) 10 1 1 100 120 140 160 180 200 220 240 260 280 300 Temperature (K...The freon is kept in a 30cm diameter by 10cm deep SS cryostat large enough to accomodate a 15cm diameter by 5cm deep liquid xenon cell and copper

  3. Measurement of the transverse diffusion coefficient of charge in liquid xenon

    CERN Document Server

    Chen, W -T; Cussonneau, J -P; Donnard, J; Duval, S; Mohamad-Hadi, A -F; Lamblin, J; Lemaire, O; Ray, P Le; Morteau, E; Oger, T; Scotto-Lavina, L; Stutzmann, J -S; Thers, D

    2011-01-01

    Liquid xenon (LXe) is a very attractive material as a detection medium for ionization detectors due to its high density, high atomic number, and low energy required to produce electron-ion pairs. Therefore it has been used in several applications, like {\\gamma} detection or direct detection of dark matter. Now Subatech is working on the R & D of LXe Compton telescope for 3{\\gamma} medical imaging, which can make precise tridimensional localization of a ({\\beta}+, {\\gamma}) radioisotope emitter. The diffusion of charge carriers will directly affect the spatial resolution of LXe ionization signal. We will report how we measure the transverse diffusion coefficient for different electric field (0.5 ~ 1.2 kV/cm) by observing the spray of charge carriers on drift length varying until 12cm. With very-low-noise front-end electronics and complete Monte-Carlo simulation of the experiment, the values of transverse diffusion coefficient are measured precisely.

  4. A liquid hydrogen target for the calibration of the MEG and MEG II liquid xenon calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Signorelli, G., E-mail: giovanni.signorelli@pi.infn.it [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Baldini, A.M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Bemporad, C.; Cei, F.; Nicolò, D. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Università di Pisa, Dipartimento di Fisica, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Galli, L.; Gallucci, G.; Grassi, M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Papa, A. [Paul Scherrer Institut, 5232 Villigen (Switzerland); Sergiampietri, F. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Venturini, M. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy)

    2016-07-11

    We designed, built and operated a liquid hydrogen target for the calibration of the liquid xenon calorimeter of the MEG experiment. The target was used throughout the entire data taking period, from 2008 to 2013 and it is being refurbished and partly re-designed to be integrated and used in the MEG-II experiment.

  5. Application of scintillating properties of liquid xenon and silicon photomultiplier technology to medical imaging

    Science.gov (United States)

    Gomez-Cadenas, J. J.; Benlloch-Rodriguez, J. M.; Ferrario, Paola

    2016-04-01

    We describe a new positron emission time-of-flight apparatus using liquid xenon. The detector is based in a liquid xenon scintillating cell. The cell shape and dimensions can be optimized depending on the intended application. In its simplest form, the liquid xenon scintillating cell is a box in which two faces are covered by silicon photomultipliers and the others by a reflecting material such as Teflon. It is a compact, homogenous and highly efficient detector which shares many of the desirable properties of monolithic crystals, with the added advantage of high yield and fast scintillation offered by liquid xenon. Our initial studies suggest that good energy and spatial resolution comparable with that achieved by lutetium oxyorthosilicate crystals can be obtained with a detector based in liquid xenon scintillating cells. In addition, the system can potentially achieve an excellent coincidence resolving time of better than 100 ps.

  6. A New Electrostatically-focused UV HPD for Liquid Xenon

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, Priscilla Brooks [University of Minnesota

    2013-07-10

    Appropriate photodetectors are a major challenge for liquid xenon technology as proposed by the next generation of double beta decay, solar neutrino, and dark matter searches. The primary photon signal is tiny and in the hard ultraviolet, the installation is cryogenic, and the sensors themselves must not introduce background. Hybrid photodiodes (HPDs) provide an easy substitute for a conventional PMT with the added advantages of low radioactivity, better area coverage, and single photoelectron counting. A computer-controlled test setup capable of characterizing optical properties of ultraviolet photodetectors was installed. It was used to compare photomultiplier tubes, silicon photomultipliers, avalanche photodiodes, and a novel-design custom HPD developed by the DEP company under this proposal.

  7. PandaX: a liquid xenon dark matter experiment at CJPL

    Science.gov (United States)

    Cao, XiGuang; Chen, Xun; Chen, YunHua; Cui, XiangYi; Fang, DeQing; Fu, ChangBo; Giboni, Karl L.; Gong, HaoWei; Guo, GuoDong; He, Ming; Hu, Jie; Huang, XingTao; Ji, XiangDong; Ju, YongLin; Li, ShaoLi; Lin, Qing; Liu, HuaXuan; Liu, JiangLai; Liu, Xiang; Lorenzon, Wolfgang; Ma, YuGang; Mao, YaJun; Ni, KaiXuan; Pushkin, Kirill; Ren, XiangXiang; Schubnell, Michael; Shen, ManBing; Shi, YuJie; Stephenson, Scott; Tan, AnDi; Tarlé, Greg; Wang, HongWei; Wang, JiMing; Wang, Meng; Wang, XuMing; Wang, Zhou; Wei, YueHuan; Wu, ShiYong; Xiao, MengJiao; Xiao, Xiang; Xie, PengWei; Ye, Tao; You, YingHui; Zen, XiongHui; Zhang, Hua; Zhang, Tao; Zhao, HaiYing; Zhao, Li; Zhou, XiaoPeng; Zhu, ZhongHua

    2014-08-01

    PandaX is a large liquid-xenon detector experiment usable for direct dark-matter detection and 136Xe double-beta decay search. The central vessel was designed to accommodate a staged target volume increase from initially 120 kg (stage I) to 0.5 t (stage II) and eventually to a multi-ton scale. The experiment is located in the Jinping Deep-Underground Laboratory in Sichuan, China. The detector operates in dual-phase mode, allowing detection of both prompt scintillation, and ionization charge through proportional scintillation. In this paper a detailed description of the stage I detector design and performance as well as results established during the commissioning phase are presented.

  8. PandaX: A Liquid Xenon Dark Matter Experiment at CJPL

    CERN Document Server

    Cao, X G; Chen, Y H; Cui, X Y; Fang, D Q; Fu, C B; Giboni, K L; Gong, H W; Guo, G D; He, M; Hu, J; Huang, X T; Ji, X D; Ju, Y L; Li, S L; Lin, Q; Liu, H X; Liu, J L; Liu, X; Lorenzon, W; Ma, Y G; Mao, Y J; Ni, K X; Pushkin, K; Ren, X X; Schubnell, M; Shen, M B; Shi, Y J; Stephenson, S; Tan, A D; Tarle, G; Wang, H W; Wang, J M; Wang, M; Wang, X M; Wang, Z; Wei, Y H; Wu, S Y; Xiao, M J; Xiao, X; Xie, P W; Ye, T; You, Y H; Zeng, X H; Zhang, H; Zhang, T; Zhao, H Y; Zhao, L; Zhou, X P; Zhu, Z H

    2014-01-01

    PandaX is a large upgradable liquid-xenon detector system that can be used for both direct dark-matter detection and $^{136}$Xe double-beta decay search. It is located in the Jinping Deep-Underground Laboratory in Sichuan, China. The detector operates in dual-phase mode, allowing detection of both prompt scintillation, and ionization charge through proportional scintillation. The central time projection chamber will be staged, with the first stage accommodating a target mass of about 120\\,kg. In stage II, the target mass will be increased to about 0.5\\,ton. In the final stage, the detector can be upgraded to a multi-ton target mass. In this paper a detailed description of the stage-I detector design and performance results established during the commissioning phase is presented.

  9. Fully differential cross sections for low to intermediate energy perpendicular plane ionization of xenon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, G., E-mail: ghanshyam.purohit@spsu.ac.in; Singh, P.; Patidar, V.

    2014-12-15

    Highlights: • We present triply differential cross section (TDCS) results for the perpendicular plane ionization of xenon atoms. • The TDCS has been calculated in the modified distorted wave Born approximation formalism. • The effects of target polarization and post collision interaction have also been included. • The polarization potential, higher order effects and PCI has been found to be useful in the description of TDCS. - Abstract: Triple differential cross section (TDCS) results are reported for the perpendicular plane ionization of Xe (5p) at incident electron energies 5 eV, 10 eV, 20 eV, and 40 eV above ionization potential. The modified distorted wave Born approximation formalism with first as well as the second order Born terms has been used to calculate the TDCS. Effects of target polarization and post collision interaction have also been included. We compare the (e, 2e) TDCS results of our calculation with the recent available experimental data and theoretical results and discuss the process contributing to structure seen in the differential cross section. It has been observed from the present study that the second order effect and target polarization make significant contribution in description of collision dynamics of xenon at the low and intermediate energy for the perpendicular emission of electrons.

  10. Index of refraction, Rayleigh scattering length, and Sellmeier coefficients in solid and liquid argon and xenon

    CERN Document Server

    Grace, Emily

    2015-01-01

    Like all the noble elements, argon and xenon are scintillators, \\emph{i.e.} they produce light when exposed to radiation. Large liquid argon detectors have become widely used in low background experiments, including dark matter and neutrino research. However, the index of refraction of liquid argon at the scintillation wavelength has not been measured and current Rayleigh scattering length calculations disagree with measurements. Furthermore, the Rayleigh scattering length and index of refraction of solid argon and solid xenon at their scintillation wavelengths have not been previously measured or calculated. We introduce a new calculation using previously measured data in liquid and solid argon and xenon to extrapolate the optical properties at the scintillation wavelengths using the Sellmeier dispersion relationship. As a point of validation, we compare our extrapolated index of refraction for liquid xenon against the measured value and find agreement within the uncertainties. This method results in a Rayle...

  11. An Ultra-Low Background PMT for Liquid Xenon Detectors

    CERN Document Server

    Akerib, D S; Bernard, E; Bernstein, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Carr, D; Chapman, J J; Chan, Y-D; Clark, K; Coffey, T; deViveiros, L; Dragowsky, M; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Gaitskell, R J; Gibson, K R; Hall, C; Hanhardt, M; Holbrook, B; Ihm, M; Jacobsen, R G; Kastens, L; Kazkaz, K; Larsen, N; Lee, C; Lesko, K; Lindote, A; Lopes, M I; Lyashenko, A; Malling, D C; Mannino, R; McKinsey, D; Mei, D; Mock, J; Morii, M; Nelson, H; Neves, F; Nikkel, J A; Pangilinan, M; Pech, K; Phelps, P; Shutt, T; Silva, C; Skulski, W; Solovov, V N; Sorensen, P; Spaans, J; Stiegler, T; Sweany, M; Szydagis, M; Taylor, D; Thomson, J; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, J T; Wlasenko, M; Wolfs, F L H; Woods, M; Zhang, C

    2012-01-01

    Results are presented from radioactivity screening of two models of photomultiplier tubes designed for use in current and future liquid xenon experiments. The Hamamatsu 5.6 cm diameter R8778 PMT, used in the LUX dark matter experiment, has yielded a positive detection of four common radioactive isotopes: 238U, 232Th, 40K, and 60Co. Screening of LUX materials has rendered backgrounds from other detector materials subdominant to the R8778 contribution. A prototype Hamamatsu 7.6 cm diameter R11410 MOD PMT has also been screened, with benchmark isotope counts measured at <0.4 238 U / <0.3 232 Th / <8.3 40 K / 2.0+-0.2 60 Co mBq/PMT. This represents a large reduction, equal to a change of \\times 1/24 238U / \\times 1/9 232Th / \\times 1/8 40K per PMT, between R8778 and R11410 MOD, concurrent with a doubling of the photocathode surface area (4.5 cm to 6.4 cm diameter). 60Co measurements are comparable between the PMTs, but can be significantly reduced in future R11410 MOD units through further material selec...

  12. NEST: A Comprehensive Model for Scintillation Yield in Liquid Xenon

    CERN Document Server

    Szydagis, M; Kazkaz, K; Mock, J; Stolp, D; Sweany, M; Tripathi, M; Uvarov, S; Walsh, N; Woods, M

    2011-01-01

    A comprehensive model for explaining scintillation yield in liquid xenon is introduced. We unify various definitions of work function which abound in the literature and incorporate all available data on electron recoil scintillation yield. This results in a better understanding of electron recoil, and facilitates an improved description of nuclear recoil. An incident gamma energy range of O(1 keV) to O(1 MeV) and electric fields between 0 and O(10 kV/cm) are incorporated into this heuristic model. We show results from a Geant4 implementation, but because the model has a few free parameters, implementation in any simulation package should be simple. We use a quasi-empirical approach, with an objective of improving detector calibrations and performance verification. The model will aid in the design and optimization of future detectors. This model is also easy to extend to other noble elements. In this paper we lay the foundation for an exhaustive simulation code which we call NEST (Noble Element Simulation Tech...

  13. On the behavior of solutions of xenon in liquid n-alkanes: solubility of xenon in n-pentane and n-hexane.

    Science.gov (United States)

    Bonifácio, Rui P M F; Martins, Luís F G; McCabe, Clare; Filipe, Eduardo J M

    2010-12-09

    The solubility of xenon in liquid n-pentane and n-hexane has been studied experimentally, theoretically, and by computer simulation. Measurements of the solubility are reported for xenon + n-pentane as a function of temperature from 254 to 305 K. The uncertainty in the experimental data is less than 0.15%. The thermodynamic functions of solvation such as the standard Gibbs energy, enthalpy, and entropy of solvation have been calculated from Henry's law coefficients for xenon + n-pentane solutions and also for xenon + n-hexane, which were reported in previous work. The results provide a further example of the similarity between the xenon + n-alkane interaction and the n-alkane + n-alkane interactions. Using the SAFT-VR approach we were able to quantitatively predict the experimental solubility for xenon in n-pentane and semiquantitatively that of xenon in n-hexane using simple Lorentz-Berthelot combining rules to describe the unlikely interaction. Henry's constants at infinite dilution for xenon + n-pentane and xenon + n-hexane were also calculated by Monte Carlo simulation using a united atom force field to describe the n-alkane and the Widom test particle insertion method.

  14. 900-L liquid xenon cryogenic system operation for the MEG experiment

    CERN Document Server

    Haruyama, T; Mihara, S; Hisamatsu, Y; Iawamoto, W; Mori, T; Nishiguchi, H; Otani, W; Sawada, R; Uchiyama, Y; Nishitani, T

    2009-01-01

    A cryogenic system for the MEG (muon rare decay) experiment has started operation at the Paul Sherrer Institute in Zurich. The main part of the MEG detector is the 900-L liquid xenon calorimeter for gamma ray detection, equipped with 850 photo multipliers directly immersed in liquid xenon. A 200 W pulse tube cryocooler enabled LN2-free operation of this calorimeter. A liquid purification system; using a liquid pump and a zero boil-off 1000-L cryogenic buffer dewar is also included in the system. The first entire engineering run was carried out in November-December 2007 and satisfactory cryogenic performances were confirmed.

  15. Simulations of a micro-PET System based on Liquid Xenon

    CERN Document Server

    Miceli, A; Andreyev, A; Bryman, D; Kurchaninov, L; Lu, P; Muennich, A; Retiere, F; Sossi, V

    2011-01-01

    The imaging performance of a high-resolution preclinical PET system employing liquid xenon as the gamma ray detection medium was simulated. The arrangment comprises a ring of detectors consisting of trapezoidal LXe time projection ionization chambers and two arrays of large area avalanche photodiodes for the measurement of ionization charge and scintillation light. A key feature of the LXePET system is the ability to identify individual photon interactions with high energy resolution and high spatial resolution in 3 dimensions and determine the correct interaction sequence using Compton reconstruction algorithms. The simulated LXePET imaging performance was evaluated by computing the noise equivalent count rate, the sensitivity and point spread function for a point source, and by examining the image quality using a micro-Derenzo phantom according to the NEMA-NU4 standard. Results of these simulation studies included NECR peaking at 1372 kcps at 262 MBq (712 kcps at 192 MBq) for an energy window of 450 - 600 k...

  16. Electron spin polarization in strong-field ionization of xenon atoms

    Science.gov (United States)

    Hartung, Alexander; Morales, Felipe; Kunitski, Maksim; Henrichs, Kevin; Laucke, Alina; Richter, Martin; Jahnke, Till; Kalinin, Anton; Schöffler, Markus; Schmidt, Lothar Ph. H.; Ivanov, Misha; Smirnova, Olga; Dörner, Reinhard

    2016-08-01

    As a fundamental property of the electron, the spin plays a decisive role in the electronic structure of matter, from solids to molecules and atoms, for example, by causing magnetism. Yet, despite its importance, the spin dynamics of the electrons released during the interaction of atoms with strong ultrashort laser pulses has remained experimentally unexplored. Here, we report the experimental detection of electron spin polarization by the strong-field ionization of xenon atoms and support our results with theoretical analysis. We found up to 30% spin polarization changing its sign with electron energy. This work opens the new dimension of spin to strong-field physics. It paves the way to the production of sub-femtosecond spin-polarized electron pulses with applications ranging from probing the magnetic properties of matter at ultrafast timescales to testing chiral molecular systems with sub-femtosecond temporal and sub-ångström spatial resolutions.

  17. XAMS - development of liquid xenon detector technology for dark matter searches

    NARCIS (Netherlands)

    Schön, R.

    2015-01-01

    One of the most promising detector technologies to directly detect weakly interacting massive particle (WIMP) dark matter are time projection chambers (TPCs) filled with dual-phase (liquid and gaseous) xenon. The hypothetical WIMP could scatter with atoms in the liquid and the transferred recoil ene

  18. XAMS - development of liquid xenon detector technology for dark matter searches

    NARCIS (Netherlands)

    Schön, R.

    2015-01-01

    One of the most promising detector technologies to directly detect weakly interacting massive particle (WIMP) dark matter are time projection chambers (TPCs) filled with dual-phase (liquid and gaseous) xenon. The hypothetical WIMP could scatter with atoms in the liquid and the transferred recoil

  19. Self-shielding effect of a single phase liquid xenon detector for direct dark matter search

    CERN Document Server

    Minamino, A; Ashie, Y; Hosaka, J; Ishihara, K; Kobayashi, K; Koshio, Y; Mitsuda, C; Moriyama, S; Nakahata, M; Nakajima, Y; Namba, T; Ogawa, H; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takeuchi, Y; Taki, K; Ueshima, K; Ebizuka, Y; Ota, A; Suzuki, S; Hagiwara, H; Hashimoto, Y; Kamada, S; Kikuchi, M; Kobayashi, N; Nagase, T; Nakamura, S; Tomita, K; Uchida, Y; Fukuda, Y; Sato, T; Nishijima, K; Maruyama, T; Motoki, D; Itow, Y; Kim, Y D; Lee, J I; Moon, S H; Lim, K E; Cravens, J P; Smy, M B

    2009-01-01

    Liquid xenon is a suitable material for a dark matter search. For future large scale experiments, single phase detectors are attractive due to their simple configuration and scalability. However, in order to reduce backgrounds, they need to fully rely on liquid xenon's self-shielding property. A prototype detector was developed at Kamioka Observatory to establish vertex and energy reconstruction methods and to demonstrate the self-shielding power against gamma rays from outside of the detector. Sufficient self-shielding power for future experiments was obtained.

  20. Setup for SiPM characterization in liquid xenon for the nEXO experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hufschmidt, Patrick; Bayerlein, Reimund; Jamil, Ako; Schneider, Judith; Wagenpfeil, Michael; Wredel, Gerrit; Ziegler, Tobias; Anton, Gisela; Hoessl, Juergen; Michel, Thilo [ECAP, Friedrich-Alexander-Universitaet Erlangen Nuernberg (Germany)

    2016-07-01

    The nEXO (next enriched xenon observatory) is a future experiment to search for the neutrinoless double beta decay of Xe-136 with a single-phase time-projection-chamber filled with liquid xenon. Besides position resolved detection of the released charge with low noise electronics, efficient collection and detection of the xenon scintillation light with its short wavelength of 175 nm is important to obtain good energy resolution. Due to the demands on radiopurity of the materials employed in the detector, Silicon Photomultipliers (SiPM) shall be used to detect the scintillation light. Dedicated SiPMs, compatible with the requirements of the experiment, have to be developed. In order to characterize SiPMs - for example with respect to photon detection efficiency at 175 nm, cross-talk probability, dark-rate, after-pulse probability - we have set up a SiPM test stand in which SiPMs can be operated in liquid or in gaseous xenon. Cooling is performed with a cold finger immersed in liquid nitrogen. Scintillation photons are produced by the interaction of alpha particles from a radioactive source. In addition to the SiPMs, a VUV-sensitive photomultiplier tube is present in the xenon cell so that coincidence measurements can be performed. In this contribution we present the status of our test setup.

  1. Ultrasensitive resonance ionization mass spectrometer for evaluating krypton contamination in xenon dark matter detectors

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, Y., E-mail: iwata.yoshihiro@jaea.go.jp [Experimental Fast Reactor Department, Oarai Research and Development Center, Japan Atomic Energy Agency, 4002 Narita, Oarai, Ibaraki 311-1393 (Japan); Sekiya, H. [Kamioka Observatory, Institute for Cosmic Ray Research, The University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Ito, C. [Experimental Fast Reactor Department, Oarai Research and Development Center, Japan Atomic Energy Agency, 4002 Narita, Oarai, Ibaraki 311-1393 (Japan)

    2015-10-11

    An ultrasensitive resonance ionization mass spectrometer that can be applied to evaluate krypton (Kr) contamination in xenon (Xe) dark matter detectors has been developed for measuring Kr at the parts-per-trillion (ppt) or sub-ppt level in Xe. The gas sample is introduced without any condensation into a time-of-flight mass spectrometer through a pulsed supersonic valve. Using a nanosecond pulsed laser at 212.6 nm, {sup 84}Kr atoms in the sample are resonantly ionized along with other Kr isotopes. {sup 84}Kr ions are then mass separated and detected by the mass spectrometer in order to measure the Kr impurity concentration. With our current setup, approximately 0.4 ppt of Kr impurities contained in pure argon (Ar) gas are detectable with a measurement time of 1000 s. Although Kr detection sensitivity in Xe is expected to be approximately half of that in Ar, our spectrometer can evaluate Kr contamination in Xe to the sub-ppt level.

  2. RELAX Update: Recent Developments in the Resonance Ionization Mass Spectrometry of Xenon

    Science.gov (United States)

    Gilmour, J. D.; Johnston, W. A.; Lyon, I. C.; Turner, G.

    1993-07-01

    Refrigerator Enhanced Laser Analyser for Xenon (RELAX) [1] is an ultrasensitive mass spectrometer designed for the analysis of xenon from meteorites. It combines a selective laser resonance ionization ion source using a Nd:YAG based laser system for the generation of UV light pulses at 10Hz with a low volume (400cc) time-of-flight mass spectrometer. A cryogenic sample concentrator is used to increase sensitivity to the point where one count per second is produced from a sample of 1000 atoms, and this, combined with the continuous measurement of all isotopes and baselines implicit in the time-of-flight technique gives an effective sensitivity 2 orders of magnitude in excess of conventional, single-collector, magnetic sector instruments. In the past year the data acquisition system has been radically altered by the addition of discrimination against electronic noise and the development of a pulse counting system for small quantities of gas (light isotopes ^124Xe and ^126Xe. Precisions of close to 10% are achievable in under 10 minutes in calibration aliquots that contain approximately 600 atoms of ^124Xe. Gas can be released from samples using either an argon ion laser microprobe or a tantalum filament microfurnace while being observed through the laser port via a video monitoring system. The blank from the sample extraction chamber in which either the filament furnace or the laser microprobe sample mount can be fitted is not measurably higher than the dynamic blank of the spectrometer (10^-15ccSTP xenon total) however, at high filament temperatures (~1000 degrees C) the filament furnace produces a larger blank (up to 5 x 10^-15ccSTP) over the 5 minute duration of a typical sample extraction. No corresponding increase in blank has been noted when the laser microprobe is in use. High resolution stepped pyrolysis analyses of acid residues from the Murchison meteorite have been performed using the filament furnace in preference to the laser probe because of the greater

  3. Measurement of the absolute reflectance of polytetrafluoroethylene (PTFE) immersed in liquid xenon

    Science.gov (United States)

    Neves, F.; Lindote, A.; Morozov, A.; Solovov, V.; Silva, C.; Bras, P.; Rodrigues, J. P.; Lopes, M. I.

    2017-01-01

    The performance of a detector using liquid xenon (LXe) as a scintillator is strongly dependent on the collection efficiency for xenon scintillation light, which in turn is critically dependent on the reflectance of the surfaces that surround the active volume. To improve the light collection in such detectors the active volume is usually surrounded by polytetrafluoroethylene (PTFE) reflector panels, used due to its very high reflectance—even at the short wavelength of scintillation light of LXe (peaked at 178 nm). In this work, which contributed to the overall R&D effort towards the LUX-ZEPLIN (LZ) experiment, we present experimental results for the absolute reflectance measurements of three different PTFE samples (including the material used in the LUX detector) immersed in LXe for its scintillation light. The obtained results show that very high bi-hemispherical reflectance values (>= 97%) can be achieved, enabling very low energy thresholds in liquid xenon scintillator-based detectors.

  4. Index of refraction, Rayleigh scattering length, and Sellmeier coefficients in solid and liquid argon and xenon

    Science.gov (United States)

    Grace, Emily; Butcher, Alistair; Monroe, Jocelyn; Nikkel, James A.

    2017-09-01

    Large liquid argon detectors have become widely used in low rate experiments, including dark matter and neutrino research. However, the optical properties of liquid argon are not well understood at the large scales relevant for current and near-future detectors. The index of refraction of liquid argon at the scintillation wavelength has not been measured, and current Rayleigh scattering length calculations disagree with measurements. Furthermore, the Rayleigh scattering length and index of refraction of solid argon and solid xenon at their scintillation wavelengths have not been previously measured or calculated. We introduce a new calculation using existing data in liquid and solid argon and xenon to extrapolate the optical properties at the scintillation wavelengths using the Sellmeier dispersion relationship.

  5. A low-mass dark matter search using ionization signals in XENON100

    CERN Document Server

    Aprile, E; Agostini, F; Alfonsi, M; Amaro, F D; Anthony, M; Arneodo, F; Barrow, P; Baudis, L; Bauermeister, B; Benabderrahmane, M L; Berger, T; Breur, P A; Breskin, A; Brown, A; Bruenner, E Brown S; Bruno, G; Budnik, R; Buss, A; Bütikofer, L; Cardoso, J M R; Cervantes, M; Cichon, D; Coderre, D; Colijn, A P; Conrad, J; Cussonneau, J P; Decowski, M P; de Perio, P; Di Gangi, P; Di Giovanni, A; Duchovni, E; Ferella, A D; Fieguth, A; Franco, D; Fulgione, W; Galloway, M; Garbini, M; Geis, C; Goetzke, L W; Greene, Z; Grignon, C; Gross, E; Hasterok, C; Hogenbirk, E; Itay, R; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Levinson, L; Calloch, M Le; Levy, C; Linde, F; Lindemann, S; Lindner, M; Lopes, J A M; Lyashenko, A; Manfredini, A; Undagoitia, T Marrodán; Masbou, J; Massoli, F V; Masson, D; Mayani, D; Fernandez, A J Melgarejo; Meng, Y; Messina, M; Micheneau, K; Miguez, B; Molinario, A; Murra, M; Naganoma, J; Oberlack, U; Orrigo, S E A; Pakarha, P; Pelssers, B; Persiani, R; Piastra, F; Pienaar, J; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Rupp, N; Santos, J M F dos; Sartorelli, G; Scheibelhut, M; Schindler, S; Schreiner, J; Schumann, M; Lavina, L Scotto; Selvi, M; Shagin, P; Simgen, H; Stein, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C D; von Sivers, M; Wall, R; Wang, H; Weber, M; Wei, Y; Weinheimer, C; Wulf, J; Zhang, Y

    2016-01-01

    We perform a low-mass dark matter search using an exposure of 30 kg$\\times$yr with the XENON100 detector. By dropping the requirement of a scintillation signal and using only the ionization signal to determine the interaction energy, we lowered the energy threshold for detection to 0.7 keV for nuclear recoils. No dark matter detection can be claimed because a complete background model cannot be constructed without a primary scintillation signal. Instead, we compute an upper limit on the WIMP-nucleon scattering cross section under the assumption that every event passing our selection criteria could be a signal event. Using an energy interval from 0.7 keV to 9.1 keV, we derive a limit on the spin-independent WIMP-nucleon cross section that excludes WIMPs with a mass of 6 GeV/$c^2$ above $1.2 \\times 10^{-41}$ cm$^2$ at 90\\% confidence level.

  6. Design and construction of a cryogenic distillation device for removal of krypton for liquid xenon dark matter detectors.

    Science.gov (United States)

    Wang, Zhou; Bao, Lei; Hao, Xihuan; Ju, Yonglin

    2014-01-01

    Liquid xenon (Xe) is one of the commendable detecting media for the dark matter detections. However, the small content of radioactive krypton-85 ((85)Kr) always exists in the commercial xenon products. An efficient cryogenic distillation system to remove this krypton (Kr) from commercial xenon products has been specifically designed, developed, and constructed in order to meet the requirements of the dark matter experiments with high- sensitivity and low-background. The content of krypton in regular commercial xenon products can be reduced from 10(-9) to 10(-12), with 99% xenon collection efficiency at maximum flow rate of 5 kg/h (15SLPM). The purified xenon gases produced by this distillation system can be used as the detecting media in the project of Panda X, which is the first dark matter detector developed in China.

  7. Ab initio electron scattering cross-sections and transport in liquid xenon

    Science.gov (United States)

    Boyle, G. J.; McEachran, R. P.; Cocks, D. G.; Brunger, M. J.; Buckman, S. J.; Dujko, S.; White, R. D.

    2016-09-01

    Ab initio fully differential cross-sections for electron scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework (Boyle et al 2015 J. Chem. Phys. 142 154507) which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann’s equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10-4-1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculations.

  8. Ab-initio electron scattering cross-sections and transport in liquid xenon

    CERN Document Server

    Boyle, Greg; Cocks, Daniel; Brunger, Michael; Buckman, Steve; Dujko, Sasa; White, Ron

    2016-01-01

    Ab-initio electron - liquid phase xenon fully differential cross-sections for electrons scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework [1] which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann's equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10^{-4} to 1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to transform highly accurate gas-phase cross-sections to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculatio...

  9. Search for solar axions in XMASS, a large liquid-xenon detector

    CERN Document Server

    Abe, K; Hiraide, K; Hirano, S; Kishimoto, Y; Kobayashi, K; Moriyama, S; Nakagawa, K; Nakahata, M; Ogawa, H; Oka, N; Sekiya, H; Suzuki, A Shinozaki Y; Takeda, A; Takachio, O; Ueshima, K; Umemoto, D; Yamashita, M; Yang, B S; Tasaka, S; Liu, J; Martens, K; Hosokawa, K; Miuchi, K; Murata, A; Onishi, Y; Otsuka, Y; Takeuchi, Y; Kim, Y H; Lee, K B; Lee, M K; Lee, J S; Fukuda, Y; Itow, Y; Masuda, K; Nishitani, Y; Takiya, H; Uchida, H; Kim, N Y; Kim, Y D; Kusaba, F; Motoki, D; Nishijima, K; Fujii, K; Murayama, I; Nakamura, S

    2012-01-01

    XMASS, a low-background, large liquid-xenon detector, was used to search for solar axions that would be produced by bremsstrahlung and Compton effects in the Sun. With an exposure of 5.6ton days of liquid xenon, the model-independent limit on the coupling for mass $\\ll$ 1keV is $|g_{aee}|< 5.4\\times 10^{-11}$ (90% C.L.), which is a factor of two stronger than the existing experimental limit. The bounds on the axion masses for the DFSZ and KSVZ axion models are 1.9 and 250eV, respectively. In the mass range of 10-40keV, this study produced the most stringent limit, which is better than that previously derived from astrophysical arguments regarding the Sun to date.

  10. Search for solar axions in XMASS, a large liquid-xenon detector

    Energy Technology Data Exchange (ETDEWEB)

    Abe, K. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Hieda, K. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Hiraide, K. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Hirano, S. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kishimoto, Y.; Kobayashi, K.; Moriyama, S. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Nakagawa, K. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Nakahata, M.; Ogawa, H. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Oka, N. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Sekiya, H. [Kamioka Observatory, Institute for Cosmic Ray Research, the University of Tokyo, Higashi-Mozumi, Kamioka, Hida, Gifu 506-1205 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); and others

    2013-07-09

    XMASS, a low-background, large liquid-xenon detector, was used to search for solar axions that would be produced by bremsstrahlung and Compton effects in the Sun. With an exposure of 5.6 ton days of liquid xenon, the model-independent limit on the coupling for mass ≪1 keV is |g{sub aee}|<5.4×10{sup −11} (90% C.L.), which is a factor of two stronger than the existing experimental limit. The bounds on the axion masses for the DFSZ and KSVZ axion models are 1.9 and 250 eV, respectively. In the mass range of 10–40 keV, this study produced the most stringent limit, which is better than that previously derived from astrophysical arguments regarding the Sun to date.

  11. Investigation of the scintillation light from liquid argon doped with xenon

    Science.gov (United States)

    Minerskjöld, Maxim; Lindblad, Thomas; Lund-Jensen, Bengt; Székely, Géza

    1993-11-01

    The scintillation light induced by 241Am 5.5 MeV α- particles in liquid argon doped with about 2% xenon detected with a fused silica UV photomultiplier tube is investigated. The pulse-height spectrum, the anode pulse shape and the attenuation of the light output are measured. The latter measurement was the main task of the present investigation and an effective half-length of more than 35 mm was found.

  12. Measurement of light and charge yield of low-energy electronic recoils in liquid xenon

    CERN Document Server

    Goetzke, L W; Anthony, M; Plante, G; Weber, M

    2016-01-01

    The dependence of the light and charge yield of liquid xenon on the applied electric field and recoil energy is important for dark matter detectors using liquid xenon time projections chambers. Few measurements have been made of this field dependence at recoil energies less than 10 keV. In this paper we present results of such measurements using a specialized detector. Recoil energies are determined via the Compton coincidence technique at four drift fields relevant for liquid xenon dark matter detectors: 0.19, 0.48, 1.02, and 2.32 kV/cm. Mean recoil energies down to 1 keV were measured with unprecedented precision. We find that the charge and light yield are anti-correlated above 3 keV, and that the field dependence becomes negligible below 6 keV. However, below 3 keV we find a charge yield significantly higher than expectation and a reconstructed energy deviating from linearity.

  13. High-accuracy measurement of the emission spectrum of liquid xenon in the vacuum ultraviolet region

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Keiko, E-mail: fujii-keiko-nv@ynu.jp [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Endo, Yuya; Torigoe, Yui; Nakamura, Shogo [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Haruyama, Tomiyoshi; Kasami, Katsuyu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Mihara, Satoshi; Saito, Kiwamu; Sasaki, Shinichi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); The Graduate School of Advanced Studies, Hayama, Kanagawa 240-0193 (Japan); Tawara, Hiroko [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)

    2015-09-21

    The emission spectrum of cryogenic liquid xenon in the vacuum ultraviolet region was measured by irradiating liquid xenon with gamma-rays from a radioactive source. To achieve a high signal-to-noise ratio, we employed coincident photon counting. Additionally, the charge of the photo-sensor signals was measured to estimate the number of detected photons accurately. In addition, proper corrections were incorporated for the wavelength; response functions of the apparatus obtained using a low-pressure mercury lamp, and photon detection efficiencies of the optical system were considered. The obtained emission spectrum is found to be in the shape of a Gaussian function, with the center at 57,199±34 (stat.)±33 (syst.) cm{sup −1} (174.8±0.1 (stat.)±0.1 (syst.) nm) and the full width at half maximum of 3328±72 (stat.)±65 (syst.) cm{sup −1} (10.2±0.2 (stat.)±0.2 (sys.) nm). These results are the most accurate values obtained in terms of the data acquisition method and the calibration for the experimental system and provide valuable information regarding the high-precision instruments that employ a liquid-xenon scintillator.

  14. PETALO, a new concept for a Positron Emission TOF Apparatus based on Liquid xenOn

    CERN Document Server

    Benlloch-Rodriguez, J M

    2016-01-01

    This master thesis presents a new type of Positron Emission TOF Apparatus using Liquid xenOn (PETALO). The detector is based in the Liquid Xenon Scintillating Cell (LXSC). The cell is a box filled with liquid xenon (LXe) whose transverse dimensions are chosen to optimize packing and with a thickness optimized to contain a large fraction of the incoming photons. The entry and exit faces of the box (relative to the incoming gammas direction) are instrumented with large silicon photomultipliers (SiPMs), coated with a wavelength shifter, tetraphenyl butadiene (TPB). The non-instrumented faces are covered by reflecting Teflon coated with TPB. In this thesis we show that the LXSC can display an energy resolution of 5% FWHM, much better than that of conventional solid scintillators such as LSO/LYSO. The LXSC can measure the interaction point of the incoming photon with a resolution in the three coordinates of 1 mm. The very fast scintillation time of LXe (2 ns) and the availability of suitable sensors and electronic...

  15. Liquid ionization chambers for LET determination

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki

    Liquid ionization chambers [1] (LICs) have have been used in the last decades as background dosemeters. Since a few years LICs are also commercially available for dosimetry and are used for measurements of dose distributions where a high spatial distribution is necessary. Also in the last decades...

  16. Design and First Results of the CoDeX Liquid-Xenon Compton-Imaging Detector

    Science.gov (United States)

    Tennyson, Brian; Cahn, Sidney; Bernard, Ethan; Boulton, Elizabeth; Destefano, Nicholas; Edwards, Blair; Hackenburg, Ariana; Horn, Markus; Larsen, Nicole; Nikkel, James; Wahl, Christopher; Gai, Moshe; McKinsey, Daniel

    2016-03-01

    CoDeX (Compton-imaging Detector in Xenon) is an R&D Compton gamma-ray imaging detector that uses 30 kg of xenon in a two-phase time projection chamber. Time projection relative to the initial scintillation signal provides the vertical interaction positions, and either PMT-sensed gas electroluminescence or a charge-sensitive amplifier quantifies the drifted ionization signal. Detector features to enable Compton imaging are a pair of instrumented wire grids added to sense the horizontal position of clouds of drifted electrons that traverse the detector. Each wire is individually amplified in the cold xenon environment. Design choices addressing the thermodynamic and xenon purity constraints of this system will be discussed. We will also discuss the mechanical designs, engineering challenges, and performance of this Compton-imaging detector.

  17. Development of a liquid xenon Compton telescope dedicated to functional medical imaging; Etude et developpement d'un telescope compton au xenon liquide dedie a l'imagerie medicale fonctionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Grignon, C

    2007-12-15

    Functional imaging is a technique used to locate in three dimensions the position of a radiotracer previously injected in a patient. The two main modalities used for a clinical application to detect tumors, the SPECT and the PET, use solid scintillators as a detection medium. The objective of this thesis was to investigate the possibility of using liquid xenon in order to benefit from the intrinsic properties of this medium in functional imaging. The feasibility study of such a device has been performed by taking into account the technical difficulties specific to the liquid xenon. First of all, simulations of a liquid xenon PET has been performed using Monte-Carlo methods. The results obtained with a large liquid xenon volume are promising : we can expect a reduction of the injected activity of radiotracer, an improvement of the spatial resolution of the image and a parallax free camera. The second part of the thesis was focused on the development of a new concept of medical imaging, the three gamma imaging, based on the use of a new emitter: the 44 scandium. Associated to a classical PET camera, the Compton telescope is used to infer the incoming direction of the third gamma ray by triangulation. Therefore, it is possible to reconstruct the position of each emitter in three dimensions. This work convinced the scientific community to support the construction and characterization of a liquid xenon Compton telescope. The first camera dedicated to small animal imaging should then be operational in 2009. (author)

  18. Pulse-shape discrimination and energy resolution of a liquid-argon scintillator with xenon doping

    CERN Document Server

    Wahl, Christopher G; Lippincott, W Hugh; Nikkel, James A; Shin, Yunchang; McKinsey, Daniel N

    2014-01-01

    Liquid-argon scintillation detectors are used in fundamental physics experiments and are being considered for security applications. Previous studies have suggested that the addition of small amounts of xenon dopant improves performance in light or signal yield, energy resolution, and particle discrimination. In this study, we investigate the detector response for xenon dopant concentrations from 9 +/- 5 ppm to 1100 +/- 500 ppm xenon (by weight) in 6 steps. The 3.14-liter detector uses tetraphenyl butadiene (TPB) wavelength shifter with dual photomultiplier tubes and is operated in single-phase mode. Gamma-ray-interaction signal yield of 4.0 +/- 0.1 photoelectrons/keV improved to 5.0 +/- 0.1 photoelectrons/keV with dopant. Energy resolution at 662 keV improved from (4.4 +/- 0.2)% ({\\sigma}) to (3.5 +/- 0.2)% ({\\sigma}) with dopant. Pulse-shape discrimination performance degraded greatly at the first addition of dopant, slightly improved with additional additions, then rapidly improved near the end of our dopa...

  19. LET measurements with a liquid ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Tegami, Sara

    2013-02-08

    Deep-seated tumors can be efficiently treated with heavy charged particles. The characteristic depth dose profile inside the tissue (Bragg peak) allows to deliver a high dose inside the tumor, while sparing the neighboring healthy tissue. As compared to protons, heavy ions like carbon or oxygen produce a higher amount of ionization events along their track (and in particular at the end of the ion beam path), resulting in an irreparable damage to the DNA of the tumor cells. The density of such ionization events is described in terms of Linear Energy Transfer (LET), an important physical quantity, but difficult to be measured directly. The aim of this work is to determine LET of hadrontherapy beams by using Liquid Ionization Chambers (LIC). The ionization signal in LICs is affected by recombination effects that depend on the LET of the incident radiation. Differences in recombination effects in LICs and air-filled ionization chambers can be exploited to obtain the recombination index, which can be related to the LET, calculated by Monte Carlo methods. We thus developed a method to construct a calibration curve, which relates the recombination index with the LET at each depth in water. The result of this work can be used for online monitoring of the ion beam quality.

  20. Density profile in shock wave fronts of partially ionized xenon plasmas

    CERN Document Server

    Reinholz, H; Morozov, I; Mintsev, V; Zaparoghets, Y; Fortov, V; Wierling, A

    2003-01-01

    Results for the reflection coefficient of shock-compressed dense xenon plasmas at pressures of 1.6-20 GPa and temperatures around 30 000 K are interpreted. In addition to former experiments using laser beams with lambda = 1.06 mu m, measurements at lambda = 0.694 mu m have been performed recently. Reflectivities typical for metallic systems are found at high densities. Besides free carriers, the theoretical description also takes into account the influence of the neutral component of the plasma on the reflectivity. A consistent description of the measured reflectivities is achieved only if a finite width of the shock wave front is considered.

  1. Time correlation function and finite field approaches to the calculation of the fifth order Raman response in liquid xenon

    NARCIS (Netherlands)

    DeVane, Russell; Space, Brian; Jansen, Thomas L. C.; Keyes, T.

    2006-01-01

    The fifth order, two-dimensional Raman response in liquid xenon is calculated via a time correlation function (TCF) theory and the numerically exact finite field method. Both employ classical molecular dynamics simulations. The results are shown to be in excellent agreement, suggesting the efficacy

  2. Measurements of Scintillation Efficiency and Pulse-Shape for Low Energy Recoils in Liquid Xenon

    CERN Document Server

    Akimov, D Y; Davidge, D; Dawson, J; Howard, A S; Ivaniouchenkov, Yu; Jones, W G; Joshi, M; Kudryavtsev, V A; Lawson, T B; Lebedenko, V; Lehner, M J; Lightfoot, P K; Liubarsky, I; Lüscher, R; McMillan, J E; Peak, C D; Quenby, J J; Spooner, N J C; Sumner, T J; Tovey, Daniel R; Ward, C K

    2002-01-01

    Results of observations of low energy nuclear and electron recoil events in liquid xenon scintillator detectors are given. The relative scintillation efficiency for nuclear recoils is 0.22 +/- 0.01 in the recoil energy range 40 keV - 70 keV. Under the assumption of a single dominant decay component to the scintillation pulse-shape the log-normal mean parameter T0 of the maximum likelihood estimator of the decay time constant for 6 keV < Eee < 30 keV nuclear recoil events is equal to 21.0 ns +/- 0.5 ns. It is observed that for electron recoils T0 rises slowly with energy, having a value ~ 30 ns at Eee ~ 15 keV. Electron and nuclear recoil pulse-shapes are found to be well fitted by single exponential functions although some evidence is found for a double exponential form for the nuclear recoil pulse-shape.

  3. Anisotropic diffusion of electrons in liquid xenon with application to improving the sensitivity of direct dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, P

    2011-02-14

    Electron diffusion in a liquid xenon time projection chamber has recently been used to infer the z coordinate of a particle interaction, from the width of the electron signal. The goal of this technique is to reduce the background event rate by discriminating edge events from bulk events. Analyses of dark matter search data which employ it would benefit from increased longitudinal electron diffusion. We show that a significant increase is expected if the applied electric field is decreased. This observation is trivial to implement but runs contrary to conventional wisdom and practice. We also extract a first measurement of the longitudinal diffusion coefficient, and confirm the expectation that electron diffusion in liquid xenon is highly anisotropic under typical operating conditions.

  4. Time correlation function and finite field approaches to the calculation of the fifth order Raman response in liquid xenon.

    Science.gov (United States)

    DeVane, Russell; Space, Brian; Jansen, Thomas L C; Keyes, T

    2006-12-21

    The fifth order, two-dimensional Raman response in liquid xenon is calculated via a time correlation function (TCF) theory and the numerically exact finite field method. Both employ classical molecular dynamics simulations. The results are shown to be in excellent agreement, suggesting the efficacy of the TCF approach, in which the response function is written approximately in terms of a single classical multitime TCF.

  5. Scalability study of solid xenon

    CERN Document Server

    Yoo, J; Jaskierny, W F; Markley, D; Pahlka, R B; Balakishiyeva, D; Saab, T; Filipenko, M

    2015-01-01

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified {\\it Bridgeman's technique} reproduces a large scale optically transparent solid xenon.

  6. Scalability study of solid xenon

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J.; Cease, H.; Jaskierny, W. F.; Markley, D.; Pahlka, R. B.; Balakishiyeva, D.; Saab, T.; Filipenko, M.

    2015-04-01

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified {\\it Bridgeman's technique} reproduces a large scale optically transparent solid xenon.

  7. Ionization and Coulomb explosion of Xenon clusters by intense, few-cycle laser pulses

    CERN Document Server

    Mathur, D

    2010-01-01

    Intense, ultrashort pulses of 800 nm laser light (12 fs, $\\sim$4 optical cycles) of peak intensity 5$\\times$10$^{14}$ W cm$^{-2}$ have been used to irradiate gas-phase Xe$_n$ clusters ($n$=500-25,000) so as to induce multiple ionization and subsequent Coulomb explosion. Energy distributions of exploding ions are measured in the few-cycle domain that does not allow sufficient time for the cluster to undergo Coulomb-driven expansion. This results in overall dynamics that appear to be significantly different to those in the many-cycle regime. One manifestation is that the maximum ion energies are measured to be much lower than those obtained when longer pulses of the same intensity are used. Ion yields are cluster-size independent but polarization dependent in that they are significantly larger when the polarization is perpendicular to the detection axis than along it. This unexpected behavior is qualitatively rationalized in terms of a spatially anisotropic shielding effect induced by the electronic charge clou...

  8. Scintillation-only Based Pulse Shape Discrimination for Nuclear and Electron Recoils in Liquid Xenon

    CERN Document Server

    Ueshima, K; Hiraide, K; Hirano, S; Kishimoto, Y; Kobayashi, K; Koshio, Y; Liu, J; Martens, K; Moriyama, S; Nakahata, M; Nishiie, H; Ogawa, H; Sekiya, H; Shinozaki, A; Suzuki, Y; Takeda, A; Yamashita, M; Fujii, K; Murayama, I; Nakamura, S; Otsuka, K; Takeuchi, Y; Fukuda, Y; Nishijima, K; Motoki, D; Itow, Y; Masuda, K; Nishitani, Y; Uchida, H; Tasaka, S; Ohsumi, H; Kim, Y D; Kim, Y H; Lee, K B; Lee, M K

    2011-01-01

    In a dedicated test setup at the Kamioka Observatory we studied pulse shape discrimination (PSD) in liquid xenon (LXe) for dark matter searches. PSD in LXe was based on the observation that scintillation light from electron events was emitted over a longer period of time than that of nuclear recoil events, and our method used a simple ratio of early to total scintillation light emission in a single scintillation event. Requiring an efficiency of 50% for nuclear recoil retention we reduced the electron background to 7.7\\pm1.1(stat)\\pm1.2 0.6(sys)\\times10-2 at energies between 4.8 and 7.2 keVee and to 7.7\\pm2.8(stat)\\pm2.5 2.8(sys)\\times10-3 at energies between 9.6 and 12 keVee for a scintillation light yield of 20.9 p.e./keV. Further study was done by masking some of that light to reduce this yield to 4.6 p.e./keV, the same method results in an electron event reduction of 2.4\\pm0.2(stat)\\pm0.3 0.2(sys)\\times10-1 for the lower of the energy regions above. We also observe that in contrast to nuclear recoils the ...

  9. VUV light reflectivity measurements from PTFE in Liquid Xenon for the LZ Dark Matter experiment

    Science.gov (United States)

    Pushkin, Kirill; LZ Collaboration

    2016-03-01

    The LUX-Zeplin (LZ) collaboration is the next generation of the experiment to search for Dark Matter in the Universe with a dual-phase detector based on liquid xenon (LXe) with a target mass of 7 ton. LXe dual phase detectors are very sensitive probes to search for WIMP dark matter interactions. The LZ collaboration is conducting R&D to study VUV light reflectivity from PTFE (Teflon) in LXe. Teflon is used in dual phase detectors both as an electrical insulator and as reflector of VUV scintillation light (~175 nm) to improve photon detection with photomultiplier tubes (PMTs). However, experimental data for the reflectance of VUV light from PTFE in LXe is not sufficiently conclusive. We present a new technique of measuring the light reflectivity from PTFE by varying the fractional area of the PMT in the detector. PTFE reflectivity measurements were performed as a function of Teflon wall thickness in the range of 2 mm to 9.5 mm. The method, apparatus and experimental results will be presented.

  10. A Global Analysis of Light and Charge Yields in Liquid Xenon

    CERN Document Server

    Lenardo, Brian; Szydagis, Matthew; Tripathi, Mani

    2014-01-01

    We present an updated model of light and charge yields from nuclear recoils in liquid xenon with a simultaneously constrained parameter set. A global analysis is performed using measurements of electron and photon yields compiled from all available historical data, as well as measurements of the ratio of the two. These data sweep over energies from 1 - 300 keV and external applied electric fields from 0 - 4060 V/cm. The model is constrained by constructing global cost functions and using a gradient descent minimizer, a simulated annealing algorithm, and a Markov Chain Monte Carlo approach to optimize and find confidence intervals on all free parameters in the model. This analysis contrasts with previous work in that we do not unnecessarily exclude data sets nor impose artificially conservative assumptions, do not use spline functions, and reduce the number of parameters used in NEST v0.98. We report our results and the calculated best-fit charge and light yields. These quantities are crucial to understanding ...

  11. Electronic excited states as a probe of surface adsorbate structure and dynamics in liquid xenon

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Eric Scott [Univ. of California, Berkeley, CA (United States)

    1992-08-01

    A combination of second harmonic generation (SHG) and a simple dipole-dipole interaction model is presented as a new technique for determining adsorbate geometries on surfaces. The polarization dependence of SHG is used to define possible geometries of the adsorbate about the surface normal. Absorption band shifts using geometry constraints imposed by SHG data are derived for a dimer constructed from two arbitrarily placed monomers on the surface using the dipole-dipole interaction potential. These formulae can be used to determine the orientation of the two monomers relative to each other. A simplified version of this formalism is used to interpret absorption band shifts for rhodamine B adsorbed on fused silica. A brief history of the exciton is given with particular detail to Xe. Data are presented for transient absorption at RT in liquid xenon on the picosecond time scale. These are observations of both tunneling through the barrier that separates the free and trapped exciton states and the subsequent trapping of the exciton. In high densities both of these processes are found to occur within 2 to 6 picoseconds in agreement with theories of Kmiecik and Schreiber and of Martin. A threshold density is observed that separates relaxation via single binary collisions and relaxation that proceeds via Martin`s resonant energy transfer hopping mechanism.

  12. Electronic excited states as a probe of surface adsorbate structure and dynamics in liquid xenon

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, E.S.

    1992-08-01

    A combination of second harmonic generation (SHG) and a simple dipole-dipole interaction model is presented as a new technique for determining adsorbate geometries on surfaces. The polarization dependence of SHG is used to define possible geometries of the adsorbate about the surface normal. Absorption band shifts using geometry constraints imposed by SHG data are derived for a dimer constructed from two arbitrarily placed monomers on the surface using the dipole-dipole interaction potential. These formulae can be used to determine the orientation of the two monomers relative to each other. A simplified version of this formalism is used to interpret absorption band shifts for rhodamine B adsorbed on fused silica. A brief history of the exciton is given with particular detail to Xe. Data are presented for transient absorption at RT in liquid xenon on the picosecond time scale. These are observations of both tunneling through the barrier that separates the free and trapped exciton states and the subsequent trapping of the exciton. In high densities both of these processes are found to occur within 2 to 6 picoseconds in agreement with theories of Kmiecik and Schreiber and of Martin. A threshold density is observed that separates relaxation via single binary collisions and relaxation that proceeds via Martin's resonant energy transfer hopping mechanism.

  13. Nuclear recoil scintillation and ionisation yields in liquid xenon from ZEPLIN-III data

    CERN Document Server

    Horn, M; Akimov, D Yu; Araújo, H M; Barnes, E J; Burenkov, A A; Chepel, V; Currie, A; Edwards, B; Ghag, C; Hollingsworth, A; Kalmus, G E; Kobyakin, A S; Kovalenko, A G; Lebedenko, V N; Lindote, A; Lopes, M I; Lüscher, R; Majewski, P; Murphy, A StJ; Neves, F; Paling, S M; da Cunha, J Pinto; Preece, R; Quenby, J J; Reichhart, L; Scovell, P R; Silva, C; Solovov, V N; Smith, N J T; Smith, P F; Stekhanov, V N; Sumner, T J; Thorne, C; de Viveiros, L; Walker, R J

    2011-01-01

    Scintillation and ionisation yields for nuclear recoils in liquid xenon above 10 keVnr (nuclear recoil energy) are deduced from data acquired using broadband Am-Be neutron sources. The nuclear recoil data from several exposures to two sources were compared to detailed simulations. Energy-dependent scintillation and ionisation yields giving acceptable fits to the data were derived. Efficiency and resolution effects are treated using a light collection Monte Carlo, measured photomultiplier response profiles and hardware trigger studies. A gradual fall in scintillation yield below ~40 keVnr is found, together with a rising ionisation yield; both are in good agreement with the latest independent measurements. The analysis method is applied to both the most recent ZEPLIN-III data, acquired with a significantly upgraded detector and a precision-calibrated Am-Be source, as well as to the earlier data from the first run in 2008. A new method for deriving the recoil scintillation yield, which includes sub-threshold S1...

  14. Compton Positron Emission Tomography with a Liquid Xenon Time Projection Chamber

    CERN Document Server

    Giboni, K; Doke, T; Suzuki,, S; Fernandes, L M P; Lopes, J A M; Dos Santos, J M F

    2007-01-01

    Most background noise in medical Positron Emission Tomography (PET) imaging originates from photons which Compton scatter before they leave the body of the patient. In only 4% of total events do both photons leave the body un-scattered and are therefore useful for current PET imaging. In an additional 8% of the events one of the photons scatters only once. This class of events can be analyzed correctly with Compton reconstruction. A detector with sufficiently good energy, position, and multiple hit resolution can recognize these events and process them properly. By virtue of recent technological progress, Liquid Xenon Time Projection Chambers (LXeTPCs) match these requirements. A ring of small LXeTPCs can measure the energy with better than 4% FWHM and the position with less than 1 mm RMS. It also has the capability to reconstruct all interaction points. These data are required for Compton imaging. With an improved energy resolution over existing crystal scintillators (LSO/LYSO,BGO and GSO), more of the remai...

  15. Electron Recoil rejection by decay time measurement in large liquid Xenon detectors

    Science.gov (United States)

    Namwongsa, P.; Banjongkan, A.; Chen, X.; Giboni, K. L.; Ji, X.; Kobdaj, C.; Kusano, H.; Yupeng, Y.

    2017-04-01

    Very large Liquid Xenon (LXe) Time Projection Chambers (TPC) are employed to search for Dark Matter (DM). The DM particles are supposed to interact with the whole nucleus, compared to background of γ-rays, which interact with the electrons. Therefore, DM signals are caused by Nuclear Recoil (NR) instead of the Electron Recoils (ER). In ER and NR events differ in pulse shape since the ratios of light from direct scintillation and recombination are different. To discriminate against residual ER events would be possible if one can distinguish the differences in decay times. This method can be successfully applied in Liquid Argon TPCs. In LXe, however, it is generally assumed that these differences are too small to be distinguished at low energies. The easiest algorithm of Pulse Shape Discrimination (PSD) distinguishes the event type based on the number of photons emitted much later than the longest decay time. At low energies too much of the timing information is lost, and this method does not perform well. However, the timing of all photons does contain sufficient information. If we use sufficiently fast PMTs, have a large enough bandwidth in the Front End electronics, and avoid reflections then we should reach a background rejection better than 10-2 even at 2 keVee. In our Decay Time Measurement (DTM) method the decay curves are compared with a model on an event by event basis. Statistically this is independent from the charge over light (`S2/S1') cut normally applied in Dual Phase detectors. Applying both rejection mechanisms a LXeTPC can become `quasi background free'.

  16. Attenuation of vacuum ultraviolet light in pure and xenon-doped liquid argon - an approach to an assignment of the near-infrared emission from the mixture

    CERN Document Server

    Neumeier, A; Himpsl, A; Oberauer, L; Potzel, W; Schönert, S; Ulrich, A

    2015-01-01

    Results of transmission experiments of vacuum ultraviolet light through a 11.6 cm long cell filled with pure and xenon-doped liquid argon are described. Pure liquid argon shows no attenuation down to the experimental short-wavelength cut-off at 118nm. Based on a conservative approach, a lower limit of 1.10 m for the attenuation length of its own scintillation light could be derived. Adding xenon to liquid argon at concentrations on the order of parts per million leads to strong xenon-related absorption features which are used for a tentative assignment of the recently found near-infrared emission observed in electron-beam excited liquid argon-xenon mixtures. Two of the three absorption features can be explained by perturbed xenon transitions and the third one by a trapped exciton (Wannier-Mott) impurity state. A calibration curve connecting the equivalent width of the absorption line at 140 nm with xenon concentration is provided.

  17. Scintillation-only based pulse shape discrimination for nuclear and electron recoils in liquid xenon

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, K., E-mail: ueshima@suketto.icrr.u-tokyo.ac.jp [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Abe, K.; Hiraide, K.; Hirano, S. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Kishimoto, Y. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Kobayashi, K.; Koshio, Y. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Liu, J.; Martens, K. [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Moriyama, S.; Nakahata, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Nishiie, H.; Ogawa, H.; Sekiya, H.; Shinozaki, A. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Suzuki, Y. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Takeda, A. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Yamashita, M. [Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo, Kamioka, Hida, Gifu 506-1205 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); and others

    2011-12-11

    In a dedicated test setup at the Kamioka Observatory we studied pulse shape discrimination (PSD) in liquid xenon (LXe) for dark matter searches in the absence of an externally applied electric field. PSD in LXe was based on the observation that scintillation light from electron events was emitted over a longer period of time than that of nuclear recoil events, and our method used a simple ratio of early to total scintillation light emission in a single scintillation event. Requiring an efficiency of 50% for nuclear recoil retention we reduced the electron background by a factor of 7.7{+-}1.1(stat){+-}{sub 0.6}{sup 1.2}(sys) Multiplication-Sign 10{sup -2} at energies between 4.8 and 7.2 keV{sub ee} and 7.7{+-}2.8(stat){+-}{sub 2.8}{sup 2.5}(sys) Multiplication-Sign 10{sup -3} at energies between 9.6 and 12 keV{sub ee} for a scintillation light yield of 20.9 photoelectrons/keV{sub ee}. Further study was done by masking some of that light to reduce this yield to 4.6 photoelectrons/keV{sub ee}. Under these conditions the same method results in an electron event reduction by a factor of 2.4{+-}0.2(stat){+-}{sub 0.2}{sup 0.3}(sys) Multiplication-Sign 10{sup -1} for the lower of the energy regions above. We also observe that in contrast to nuclear recoils the fluctuations in our early to total ratio for electron events are larger than expected from statistical fluctuations.

  18. Measurement of the drift velocity and transverse diffusion of electrons in liquid xenon with the EXO-200 detector

    Science.gov (United States)

    Albert, J. B.; Barbeau, P. S.; Beck, D.; Belov, V.; Breidenbach, M.; Brunner, T.; Burenkov, A.; Cao, G. F.; Cen, W. R.; Chambers, C.; Cleveland, B.; Coon, M.; Craycraft, A.; Daniels, T.; Danilov, M.; Daugherty, S. J.; Daughhetee, J.; Davis, J.; Delaquis, S.; Der Mesrobian-Kabakian, A.; DeVoe, R.; Didberidze, T.; Dilling, J.; Dolgolenko, A.; Dolinski, M. J.; Dunford, M.; Fairbank, W.; Farine, J.; Feyzbakhsh, S.; Fierlinger, P.; Fudenberg, D.; Gornea, R.; Graham, K.; Gratta, G.; Hall, C.; Hughes, M.; Jewell, M. J.; Johnson, A.; Johnson, T. N.; Johnston, S.; Karelin, A.; Kaufman, L. J.; Killick, R.; Koffas, T.; Kravitz, S.; Krücken, R.; Kuchenkov, A.; Kumar, K. S.; Lan, Y.; Leonard, D. S.; Licciardi, C.; Lin, Y. H.; MacLellan, R.; Marino, M. G.; Mong, B.; Moore, D.; Njoya, O.; Nelson, R.; Odian, A.; Ostrovskiy, I.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Retière, F.; Rowson, P. C.; Russell, J. J.; Schubert, A.; Sinclair, D.; Smith, E.; Stekhanov, V.; Tarka, M.; Tolba, T.; Tsang, R.; Twelker, K.; Vuilleumier, J.-L.; Waite, A.; Walton, J.; Walton, T.; Weber, M.; Wen, L. J.; Wichoski, U.; Wood, J.; Yang, L.; Yen, Y.-R.; Zeldovich, O. Ya.; Zettlemoyer, J.; EXO-200 Collaboration

    2017-02-01

    The EXO-200 Collaboration is searching for neutrinoless double β decay using a liquid xenon (LXe) time projection chamber. This measurement relies on modeling the transport of charge deposits produced by interactions in the LXe to allow discrimination between signal and background events. Here we present measurements of the transverse diffusion constant and drift velocity of electrons at drift fields between 20 V/cm and 615 V/cm using EXO-200 data. At the operating field of 380 V/cm EXO-200 measures a drift velocity of 1 .705-0.010+0.014mm /μ s and a transverse diffusion coefficient of 55 ±4 cm2 /s.

  19. Measurement of the Drift Velocity and Transverse Diffusion of Electrons in Liquid Xenon with the EXO-200 Detector

    CERN Document Server

    :,; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Cen, W R; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Daughhetee, J; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dilling, J; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feyzbakhsh, S; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Hughes, M; Jewell, M J; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Krucken, R; Kuchenkov, A; Kumar, K S; Lan, Y; Leonard, D S; Licciardi, C; Lin, Y H; MacLellan, R; Marino, M G; Mong, B; Moore, D; Njoya, O; Nelson, R; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Retiere, F; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya; Zettlemoyer, J

    2016-01-01

    The EXO-200 Collaboration is searching for neutrinoless double beta decay using a liquid xenon (LXe) time projection chamber. This measurement relies on modeling the transport of charge deposits produced by interactions in the LXe to allow discrimination between signal and background events. Here we present measurements of the transverse diffusion constant and drift velocity of electrons at drift fields between 20~V/cm and 615~V/cm using EXO-200 data. At the operating field of 380~V/cm EXO-200 measures a drift velocity of 1.705$_{-0.010}^{+0.014}$~mm/$\\mu$s and a transverse diffusion coefficient of 55$\\pm$4~cm$^2$/s.

  20. The Electron Recoil Response of the XENON1T Dark Matter Experiment

    Science.gov (United States)

    Shockley, Evan; Xenon1T Collaboration

    2017-01-01

    XENON1T employs a two-phase xenon TPC to search for dark matter by detecting scintillation light produced by nuclear recoils in a 2 ton active volume of liquid xenon. However, nuclear recoils are not the only recoils that can occur since radiogenic electronic recoils are possible. Our only way of differentiating nuclear and electronic recoils is by comparing the relative fraction of scintillation (S1) and ionization (S2) signals. For the first Science Run of XENON1T, we must understand the response of our detector to S1 and S2 signals at the low keV energies where dark matter will present itself. Therefore, I will be discussing the current understanding of our signal and detection mechanisms at these energies. This work includes work using sources such as the Rn220 technique developed by XENON collaborators for understanding our rejection of electronic recoils.

  1. LET measurements with a Liquid Ionization Chamber

    OpenAIRE

    Tegami, S.

    2013-01-01

    Deep-seated tumors can be efficiently treated with heavy charged particles. The characteristic depth dose profile inside the tissue (Bragg peak) allows to deliver a high dose inside the tumor, while sparing the neighboring healthy tissue. As compared to protons, heavy ions like carbon or oxygen produce a higher amount of ionization events along their track (and in particular at the end of the ion beam path), resulting in an irreparable damage to the DNA of the tumor cells. T...

  2. First results of a large-area cryogenic gaseous photomultiplier coupled to a dual-phase liquid xenon TPC

    CERN Document Server

    Arazi, L; Erdal, E; Israelashvili, I; Rappaport, M L; Shchemelinin, S; Vartsky, D; Santos, J M F dos; Breskin, A

    2015-01-01

    We discuss recent advances in the development of cryogenic gaseous photomultipliers (GPM), for possible use in dark matter and other rare-event searches using noble-liquid targets. We present results from a 10 cm diameter GPM coupled to a dual-phase liquid xenon (LXe) TPC, demonstrating - for the first time - the feasibility of recording both primary ("S1") and secondary ("S2") scintillation signals. The detector comprised a triple Thick Gas Electron Multiplier (THGEM) structure with cesium iodide photocathode on the first element; it was shown to operate stably at 180 K with gains above 10^5, providing high single-photon detection efficiency even in the presence of large alpha particle-induced S2 signals comprising thousands of photoelectrons. S1 scintillation signals were recorded with a time resolution of 1.2 ns (RMS). The energy resolution ({\\sigma}/E) for S2 electroluminescence of 5.5 MeV alpha particles was ~9%, which is comparable to that obtained in the XENON100 TPC with PMTs. The results are discusse...

  3. LET measurements with a Liquid Ionization Chamber

    OpenAIRE

    Tegami, S.

    2013-01-01

    Deep-seated tumors can be efficiently treated with heavy charged particles. The characteristic depth dose profile inside the tissue (Bragg peak) allows to deliver a high dose inside the tumor, while sparing the neighboring healthy tissue. As compared to protons, heavy ions like carbon or oxygen produce a higher amount of ionization events along their track (and in particular at the end of the ion beam path), resulting in an irreparable damage to the DNA of the tumor cells. The density of such...

  4. Optimization of a single-phase liquid xenon Compton camera for 3γ medical imaging

    OpenAIRE

    Gallego Manzano, Lucia

    2016-01-01

    The work described in this thesis is focused on the characterization and optimization of a single-phaseliquid xenon Compton camera for medical imaging applications. The detector has been conceived to exploit the advantages of an innovative medical imaging technique called 3γ imaging, which aims to obtain aprecise 3D location of a radioactive source with high sensitivity and an important reduction of the dose administered to the patient. The 3γ imaging technique is based on the detection in co...

  5. Polymerization, shock cooling and ionization of liquid nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ross, M; Rogers, F

    2005-07-21

    The trajectory of thermodynamic states passed through by the nitrogen Hugoniot starting from the liquid and up to 10{sup 6} GPa has been studied. An earlier report of cooling in the doubly shocked liquid, near 50 to 100 GPa and 7500 K, is revisited in light of the recent discovery of solid polymeric nitrogen. It is found that cooling occurs when the doubly shocked liquid is driven into a volume near the molecular to polymer transition and raising the possibility of a liquid-liquid phase transition (LLPT). By increasing the shock pressure and temperature by an order of magnitude, theoretical calculations predict thermal ionization of the L shell drives the compression maxima to 5-6 fold compression at 10 Mbar (T {approx} 3.5 10{sup 5} K) and at 400 Mbar (T {approx} 2.3 10{sup 6} K) from K shell ionization. Near a pressure of 10{sup 6} GPa the K shell ionizes completely and the Hugoniot approaches the classical ideal gas compression fourfold limit.

  6. Performance of the Light Trigger System in the Liquid Xenon Gamma-Ray Telescope LXeGRIT

    CERN Document Server

    Oberlack, U; Curioni, A; Giboni, K; 10.1109/23.958720

    2009-01-01

    LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics, based on a liquid xenon time projection chamber with charge and light readout. The energy and direction of an incident gamma-ray is reconstructed from the three-dimensional locations and energy deposits of individual interactions taking place in the homogeneous detector volume. While the charge signals provide energy information and X-Y positions, the fast xenon scintillation light signal is used to trigger the detector. The drift time measurement, referred to the time of the trigger signal, gives the Z-position with the known drift velocity. The light is detected by four UV-sensitive photomultiplier tubes (PMTs). The logical OR of the PMT signals triggers the data acquisition system with an efficiency which depends on the event energy and location, as well as on the discriminator thresholds used on the individual PMTs. Results from experiments with a tagged 22Na source give the spatial distribution of the light trigger efficiency fo...

  7. Investigation of the CRT performance of a PET scanner based in liquid xenon: A Monte Carlo study

    CERN Document Server

    Gomez-Cadenas, J J; Ferrario, P; Monrabal, F; Rodríguez, J; Toledo, J F

    2016-01-01

    The measurement of the time of flight of the two 511 keV gammas recorded in coincidence in a PET scanner provides an effective way of reducing the random background and therefore increases the scanner sensitivity, provided that the coincidence resolving time (CRT) of the gammas is sufficiently good. Existing commercial systems based in LYSO crystals, such as the GEMINIS of Philips, reach CRT values of ~ 600 ps (FWHM). In this paper we present a Monte Carlo investigation of the CRT performance of a PET scanner exploiting the scintillating properties of liquid xenon. We find that an excellent CRT of 60-70 ps (depending on the PDE of the sensor) can be obtained if the scanner is instrumented with silicon photomultipliers (SiPMs) sensitive to the ultraviolet light emitted by xenon. Alternatively, a CRT of 120 ps can be obtained instrumenting the scanner with (much cheaper) blue-sensitive SiPMs coated with a suitable wavelength shifter. These results show the excellent time of flight capabilities of a PET device b...

  8. Space-charge effects in liquid argon ionization chambers

    Science.gov (United States)

    Rutherfoord, J. P.; Walker, R. B.

    2015-03-01

    We have uniformly irradiated liquid argon ionization chambers with betas from high-activity 90Sr sources. The radiation environment is similar to that in the liquid argon calorimeters which are part of the ATLAS detector installed at CERN's Large Hadron Collider (LHC). We measured the resulting ionization current over a wide range of applied potential for two different source activities and for three different chamber gaps. These studies provide operating experience at exceptionally high ionization rates. In particular they indicate a stability at the 0.1% level for these calorimeters over years of operation at the full LHC luminosity when operated in the normal mode at an electric field E = 1.0 kV / mm. We can operate these chambers in the normal mode or in the space-charge limited regime and thereby determine the transition point between the two. This transition point is parameterized by a positive argon ion mobility of μ+ = 0.08 ± 0.02mm2 / V s at a temperature of 88.0±0.5 K and at a pressure of 1.02±0.02 bar. In the space-charge limited regime the ionization currents are degraded and show signs of instability. At the highest electric fields in our study (6.7 kV/mm) the ionization current is still slowly rising with increasing electric field.

  9. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    Energy Technology Data Exchange (ETDEWEB)

    University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

    2011-07-19

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

  10. Soft Ionization of Thermally Evaporated Hypergolic Ionic Liquid Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Christine J. [Univ. of California, Berkeley, CA (United States); Liu, Chen-Lin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Harmon, Christopher W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Strasser, Daniel [Univ. of California, Berkeley, CA (United States); Golan, Amir [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kostko, Oleg [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chambreau, Steven D. [Edwards Air Force Base, ERC Inc., CA (United States); Vaghjiani, Ghanshyam L. [Air Force Research Laboratory, Edwards Air Force Base, CA (United States); Leone, Stephen R. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-04-20

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N–]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca–]), are generated by vaporizing ionic liquid submicrometer aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Also, hotoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~0.3 eV), attributed to reduced internal energy of the isolated ion pairs. Lastly, the method of ionic liquid submicrometer aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally “cooler” source of isolated intact ion pairs in the gas phase compared to effusive sources.

  11. Soft Ionization of Thermally Evaporated Hypergolic Ionic Liquid Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Christine J. [Univ. of California, Berkeley, CA (United States); Liu, Chen-Lin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Harmon, Christopher W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Strasser, Daniel [Univ. of California, Berkeley, CA (United States); Golan, Amir [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kostko, Oleg [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chambreau, Steven D. [Edwards Air Force Base, ERC Inc., CA (United States); Vaghjiani, Ghanshyam L. [Air Force Research Laboratory, Edwards Air Force Base, CA (United States); Leone, Stephen R. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-04-20

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N–]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca–]), are generated by vaporizing ionic liquid submicrometer aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Also, hotoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~0.3 eV), attributed to reduced internal energy of the isolated ion pairs. Lastly, the method of ionic liquid submicrometer aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally “cooler” source of isolated intact ion pairs in the gas phase compared to effusive sources.

  12. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

    Energy Technology Data Exchange (ETDEWEB)

    University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

    2011-07-19

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

  13. Soft ionization of thermally evaporated hypergolic ionic liquid aerosols.

    Science.gov (United States)

    Koh, Christine J; Liu, Chen-Lin; Harmon, Christopher W; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D; Vaghjiani, Ghanshyam L; Leone, Stephen R

    2011-05-12

    Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim(+)][Tf(2)N(-)]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim(+)][Dca(-)]), are generated by vaporizing ionic liquid submicrometer aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim(+) and Bmim(+), presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim(+)][Tf(2)N(-)] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (∼0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicrometer aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally "cooler" source of isolated intact ion pairs in the gas phase compared to effusive sources.

  14. A novel liquid-Xenon detector concept for combined fast-neutrons and gamma imaging and spectroscopy

    Science.gov (United States)

    Breskin, A.; Israelashvili, I.; Cortesi, M.; Arazi, L.; Shchemelinin, S.; Chechik, R.; Dangendorf, V.; Bromberger, B.; Vartsky, D.

    2012-06-01

    A new detector concept is presented for combined imaging and spectroscopy of fast-neutrons and gamma rays. It comprises a liquid-Xenon (LXe) converter and scintillator coupled to a UV-sensitive gaseous imaging photomultiplier (GPM). Radiation imaging is obtained by localization of the scintillation-light from LXe with the position-sensitive GPM. The latter comprises a cascade of Thick Gas Electron Multipliers (THGEM), where the first element is coated with a CsI UV-photocathode. We present the concept and provide first model-simulation results of the processes involved and the expected performances of a detector having a LXe-filled capillaries converter. The new detector concept has potential applications in combined fast-neutron and gamma-ray screening of hidden explosives and fissile materials with pulsed sources.

  15. A correction to Birks' Law in liquid argon ionization chamber simulations for highly ionizing particles

    Energy Technology Data Exchange (ETDEWEB)

    Burdin, Sergey [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Horbatsch, Marko [Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada); Taylor, Wendy, E-mail: taylorw@yorku.ca [Department of Physics and Astronomy, York University, Toronto, ON, M3J 1P3 (Canada)

    2012-02-01

    We present a study of the performance of Birks' Law in liquid argon ionization chamber simulations as applied to highly ionizing particles, such as particles with multiple electric charges or with magnetic charge. We used Birks' Law to model recombination effects in a GEANT4 simulation of heavy ions in a liquid argon calorimeter. We then compared the simulation to published heavy-ion data to extract a highly ionizing particle correction to Birks' Law.

  16. Use of a liquid ionization chamber for stereotactic radiotherapy dosimetry.

    Science.gov (United States)

    Wagner, A; Crop, F; Lacornerie, T; Vandevelde, F; Reynaert, N

    2013-04-21

    Liquid ionization chambers (LICs) offer an interesting tool in the field of small beam dosimetry, allowing better spatial resolution and reduced perturbation effects. However, some aspects remain to be addressed, such as the higher recombination and the effects from the materials of the detector. Our aim was to investigate these issues and their impact. The first step was the evaluation of the recombination effects. Measurements were performed at different SSDs to vary the dose per pulse, and the collection efficiency was obtained. The BEAMnrc code was then used to model the Cyberknife head. Finally, the liquid ionization chamber itself was modelled using the EGSnrc-based code Cavity allowing the evaluation of the influence of the volume and the chamber materials. The liquid ionization charge collection efficiency is approximately 0.98 at 1.5 mGy pulse(-1), the highest dose per pulse that we have measured. Its impact on the accuracy of output factors is less than half a per cent. The detector modelling showed a significant contribution from the graphite electrode, up to 6% for the 5 mm collimator. The dependence of the average electronic mass collision stopping power of iso-octane with beam collimation is negligible and thus has no influence on output factor measurements. Finally, the volume effect reaches 5% for the small 5 mm collimator and becomes much smaller (<0.5%) for diameters above 10 mm. LICs can effectively be used for small beam relative dosimetry as long as adequate correction factors are applied, especially for the electrode and volume effects.

  17. Nuclear medical imaging using β+γ coincidences from 44Sc radio-nuclide with liquid xenon as detection medium

    Science.gov (United States)

    Grignon, C.; Barbet, J.; Bardiès, M.; Carlier, T.; Chatal, J. F.; Couturier, O.; Cussonneau, J. P.; Faivre, A.; Ferrer, L.; Girault, S.; Haruyama, T.; Le Ray, P.; Luquin, L.; Lupone, S.; Métivier, V.; Morteau, E.; Servagent, N.; Thers, D.

    2007-02-01

    We report on a new nuclear medical imaging technique based on the measurement of the emitter location in the three dimensions with a few mm spatial resolution using β+γ emitters. Such measurement could be realized thanks to a new kind of radio-nuclides which emit a γ-ray quasi-simultaneously with the β+ decay. The most interesting radio-nuclide candidate, namely 44Sc, will be potentially produced at the Nantes cyclotron ARRONAX. The principle is to reconstruct the intersection of the classical line of response (obtained with a standard PET camera) with the direction cone defined by the third γ-ray. The emission angle measurement of this additional γ-ray involves the use of a Compton telescope for which a new generation of camera based on a liquid xenon (LXe) time projection chamber is considered. GEANT3 simulations of a large acceptance LXe Compton telescope combined with a commercial micro-PET (LSO crystals) have been performed and the obtained results will be presented. They demonstrate that a good image can be obtained from the accumulation of each three-dimensional measured position. A spatial resolution of 2.3 mm has been reached with an injected activity of 0.5 MBq for a 44Sc point source emitter.

  18. Measurements of the ion fraction and mobility of alpha and beta decay products in liquid xenon using EXO-200

    CERN Document Server

    Albert, J B; Barbeau, P S; Beck, D; Belov, V; Breidenbach, M; Brunner, T; Burenkov, A; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Danilov, M; Daugherty, S J; Davis, C G; Davis, J; Delaquis, S; Der Mesrobian-Kabakian, A; DeVoe, R; Didberidze, T; Dolgolenko, A; Dolinski, M J; Dunford, M; Fairbank, W; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Gornea, R; Graham, K; Gratta, G; Hall, C; Hughes, M; Jewell, M J; Jiang, X S; Johnson, A; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Kravitz, S; Kuchenkov, A; Kumar, K S; Leonard, D S; Licciardi, C; Lin, Y H; Ling, J; MacLellan, R; Marino, M G; Mong, B; Moore, D; Nelson, R; O'Sullivan, K; Odian, A; Ostrovskiy, I; Piepke, A; Pocar, A; Prescott, C Y; Robinson, A; Rowson, P C; Russell, J J; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tsang, R; Twelker, K; Vuilleumier, J -L; Waite, A; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Wright, J D; Wood, J; Yang, L; Yen, Y -R; Zeldovich, O Ya

    2015-01-01

    Alpha decays in the EXO-200 detector are used to measure the fraction of charged $^{218}\\mathrm{Po}$ and $^{214}\\mathrm{Bi}$ daughters created from alpha and beta decays, respectively. $^{222}\\mathrm{Rn}$ alpha decays in liquid xenon (LXe) are found to produce $^{218}\\mathrm{Po}^{+}$ ions $50.3 \\pm 3.0\\%$ of the time, while the remainder of the $^{218}\\mathrm{Po}$ atoms are neutral. The fraction of $^{214}\\mathrm{Bi}^{+}$ from $^{214}\\mathrm{Pb}$ beta decays in LXe is found to be $76.4 \\pm 5.7\\%$, inferred from the relative rates of $^{218}\\mathrm{Po}$ and $^{214}\\mathrm{Po}$ alpha decays in the LXe. The average velocity of $^{218}\\mathrm{Po}$ ions is observed to decrease for longer drift times. Initially the ions have a mobility of $0.390 \\pm 0.006~\\mathrm{cm}^2/(\\mathrm{kV}~\\mathrm{s})$, and at long drift times the mobility is $0.219 \\pm 0.004~\\mathrm{cm}^2/(\\mathrm{kV}~\\mathrm{s})$. Time constants associated with the change in mobility during drift of the $^{218}\\mathrm{Po}^{+}$ ions are found to be propor...

  19. Dark matter direct detection based on liquid xenon%基于液氙的暗物质直接探测

    Institute of Scientific and Technical Information of China (English)

    倪凯旋; 魏月环

    2011-01-01

    Direct detection of dark matter is a method to uncover the nature of dark matter. Recent year, the development of liquid xenon detection technology keeps improving the sensitivity of dark matter detection by increasing the target mass. In this article, we first calculate the expected dark matter interaction rate in a xenon target. We then describe the principles of dark matter detection using liquid xenon and the key techniques to achieve a sensitive detection, including how to detect the signals and how to control the background from various sources. The current best sensitivity achieved by liquid xenon dark matter detector is about 10-44cm2 for interaction of dark matter with the nucleon. We expect the sensitivity will be improved by 2-3 orders of magnitude in the next couple of years.%对暗物质的直接探测是探索暗物质本性的一个重要手段.近年来,随着液氙探测技术的发展,探测质量不断增大,对暗物质的探测灵敏度也不断提高.本文从暗物质在液氙探测器中预期的事例数出发,介绍了液氙探测器的信号产生和关键探测技术,以及控制探测器中本底的方法.目前液氙探测技术对暗物质与核子弹性散射截面的上限已经达到了10-44 cm2,今后几年的灵敏度会继续提高2~3个数量级,对暗物质新物理模型做出更好的限制.

  20. Application of Two Phase (Liquid/Gas) Xenon Gamma-Camera for the Detection of Special Nuclear Material and PET Medical Imaging

    Energy Technology Data Exchange (ETDEWEB)

    McKinsey, Daniel Nicholas [Yale University

    2013-08-27

    The McKinsey group at Yale has been awarded a grant from DTRA for the building of a Liquid Xenon Gamma Ray Color Camera (LXe-GRCC), which combines state-of-the-art detection of LXe scintillation light and time projection chamber (TPC) charge readout. The DTRA application requires a movable detector and hence only a single phase (liquid) xenon detector can be considered in this case. We propose to extend the DTRA project to applications that allow a two phase (liquid/gas) xenon TPC. This entails additional (yet minimal) hardware and extension of the research effort funded by DTRA. The two phase detector will have better energy and angular resolution. Such detectors will be useful for PET medical imaging and detection of special nuclear material in stationary applications (e.g. port of entry). The expertise of the UConn group in gas phase TPCs will enhance the capabilities of the Yale group and the synergy between the two groups will be very beneficial for this research project as well as the education and research projects of the two universities. The LXe technology to be used in this project has matured rapidly over the past few years, developed for use in detectors for nuclear physics and astrophysics. This technology may now be applied in a straightforward way to the imaging of gamma rays. According to detailed Monte Carlo simulations recently performed at Yale University, energy resolution of 1% and angular resolution of 3 degrees may be obtained for 1.0 MeV gamma rays, using existing technology. With further research and development, energy resolution of 0.5% and angular resolution of 1.3 degrees will be possible at 1.0 MeV. Because liquid xenon is a high density, high Z material, it is highly efficient for scattering and capturing gamma rays. In addition, this technology scales elegantly to large detector areas, with several square meter apertures possible. The Yale research group is highly experienced in the development and use of noble liquid detectors for

  1. Melting of Xenon to 80 GPa, p-d hybridization, and an ISRO liquid

    Energy Technology Data Exchange (ETDEWEB)

    Ross, M; Boehler, R; Soderlind, P

    2005-07-26

    Measurements made in a laser heated diamond-anvil cell are reported that extend the melting curve of Xe to 80 GPa and 3350 K. The steep lowering of the melting slope (dT/dP) that occurs near 17 GPa and 2750 K results from the hybridization of the p-like valence and d-like conduction states with the formation of clusters in the liquid having Icosahedral Short-Range Order (ISRO).

  2. Processing of the signals from the Liquid Xenon Calorimeter for timing measurements

    Science.gov (United States)

    Epshteyn, L. B.; Grebenuyk, A. A.; Kozyrev, A. N.; Logashenko, I. B.; Mikhaylov, K. Yu.; Ruban, A. A.; Yudin, Yu. V.

    2017-02-01

    One of the goals of the Cryogenic Magnetic Detector at Budker Institute of Nuclear Physics SB RAS (Novosibirsk, Russia) is a study of hadron production in electron-positron collisions near threshold. The neutron-antineutron pair production events can be detected only by the calorimeters. In the barrel calorimeter the antineutron annihilation typically occurs about 5 ns or later after the beams crossing. For identification of such events it is necessary to measure the time of flight of particles to the LXe-calorimeter with an accuracy of about a few nanoseconds. The LXe-calorimeter consists of 14 layers of ionization chambers with two readout: anode and cathode. The duration of charge collection to the anodes is about 4.5 μs, while the required accuracy of measuring of the signal arrival time is less than 1/1000 of that (i.e. 4.5 ns). Besides, the signals' shapes differ substantially from event to event, so the signal arrival time is measured in two stages. In the paper we describ the development of the special electronics which performs waveform digitization and the on-line measurement of signals' arrival times and amplitudes.

  3. Performance parameters of a liquid filled ionization chamber array.

    Science.gov (United States)

    Poppe, B; Stelljes, T S; Looe, H K; Chofor, N; Harder, D; Willborn, K

    2013-08-01

    In this work, the properties of the two-dimensional liquid filled ionization chamber array Octavius 1000SRS (PTW-Freiburg, Germany) for use in clinical photon-beam dosimetry are investigated. Measurements were carried out at an Elekta Synergy and Siemens Primus accelerator. For measurements of stability, linearity, and saturation effects of the 1000SRS array a Semiflex 31013 ionization chamber (PTW-Freiburg, Germany) was used as a reference. The effective point of measurement was determined by TPR measurements of the array in comparison with a Roos chamber (type 31004, PTW-Freiburg, Germany). The response of the array with varying field size and depth of measurement was evaluated using a Semiflex 31010 ionization chamber as a reference. Output factor measurements were carried out with a Semiflex 31010 ionization chamber, a diode (type 60012, PTW-Freiburg, Germany), and the detector array under investigation. The dose response function for a single detector of the array was determined by measuring 1 cm wide slit-beam dose profiles and comparing them against diode-measured profiles. Theoretical aspects of the low pass properties and of the sampling frequency of the detector array were evaluated. Dose profiles measured with the array and the diode detector were compared, and an intensity modulated radiation therapy (IMRT) field was verified using the Gamma-Index method and the visualization of line dose profiles. The array showed a short and long term stability better than 0.1% and 0.2%, respectively. Fluctuations in linearity were found to be within ±0.2% for the vendor specified dose range. Saturation effects were found to be similar to those reported in other studies for liquid-filled ionization chambers. The detector's relative response varied with field size and depth of measurement, showing a small energy dependence accounting for maximum signal deviations of ±2.6% from the reference condition for the setup used. The σ-values of the Gaussian dose response

  4. Performance parameters of a liquid filled ionization chamber array

    Energy Technology Data Exchange (ETDEWEB)

    Poppe, B.; Stelljes, T. S.; Looe, H. K.; Chofor, N. [Clinic for Radiation Therapy, Pius-Hospital, Oldenburg 26121, Germany and WG Medical Radiation Physics, Carl von Ossietzky University, Oldenburg 26121 (Germany); Harder, D. [Prof. em., Medical Physics and Biophysics, Georg August University, Göttingen 37073 (Germany); Willborn, K. [Clinic for Radiation Therapy, Pius-Hospital, Oldenburg 26121 (Germany)

    2013-08-15

    Purpose: In this work, the properties of the two-dimensional liquid filled ionization chamber array Octavius 1000SRS (PTW-Freiburg, Germany) for use in clinical photon-beam dosimetry are investigated.Methods: Measurements were carried out at an Elekta Synergy and Siemens Primus accelerator. For measurements of stability, linearity, and saturation effects of the 1000SRS array a Semiflex 31013 ionization chamber (PTW-Freiburg, Germany) was used as a reference. The effective point of measurement was determined by TPR measurements of the array in comparison with a Roos chamber (type 31004, PTW-Freiburg, Germany). The response of the array with varying field size and depth of measurement was evaluated using a Semiflex 31010 ionization chamber as a reference. Output factor measurements were carried out with a Semiflex 31010 ionization chamber, a diode (type 60012, PTW-Freiburg, Germany), and the detector array under investigation. The dose response function for a single detector of the array was determined by measuring 1 cm wide slit-beam dose profiles and comparing them against diode-measured profiles. Theoretical aspects of the low pass properties and of the sampling frequency of the detector array were evaluated. Dose profiles measured with the array and the diode detector were compared, and an intensity modulated radiation therapy (IMRT) field was verified using the Gamma-Index method and the visualization of line dose profiles.Results: The array showed a short and long term stability better than 0.1% and 0.2%, respectively. Fluctuations in linearity were found to be within ±0.2% for the vendor specified dose range. Saturation effects were found to be similar to those reported in other studies for liquid-filled ionization chambers. The detector's relative response varied with field size and depth of measurement, showing a small energy dependence accounting for maximum signal deviations of ±2.6% from the reference condition for the setup used. The σ-values of

  5. RESULTS FROM THE XENON100 EXPERIMENT

    Directory of Open Access Journals (Sweden)

    Rino Persiani

    2013-12-01

    Full Text Available The XENON program consists in operating and developing double-phase time projection chambers using liquid xenon as the target material. It aims to directly detect dark matter in the form of WIMPs via their elastic scattering off xenon nuclei. The current phase is XENON100, located at the Laboratori Nazionali del Gran Sasso (LNGS, with a 62 kg liquid xenon target. We present the 100.9 live days of data, acquired between January and June 2010, with no evidence of dark matter, as well as the new results of the last scientific run, with about 225 live days. The next phase, XENON1T, will increase the sensitivity by two orders of magnitude.

  6. Développement expérimental d'un télescope Compton au xenon liquide pour l'imagerie médicale fonctionnelle

    OpenAIRE

    Oger, Tugdual

    2012-01-01

    3γ imaging is a new nuclear medical imaging technique which has been suggested by Subatech laboratory. This technique involves locating three-dimensional position of the decay of an innovative radioisotope (β+, γ) emitter the 44Sc. The principle consist in the detection of two photons of 511 keV gamma rays from the decay of the positron, provided by a PET ring detector, associated to the detection of the third photon by a Liquid xenon Compton telescope. The energy deposited in the interaction...

  7. A measurement of the time profile of scintillation induced by low energy gamma-rays in liquid xenon with the XMASS-I detector

    CERN Document Server

    Takiya, H; Hiraide, K; Ichimura, K; Kishimoto, Y; Kobayashi, K; Kobayashi, M; Moriyama, S; Nakahata, M; Norita, T; Ogawa, H; Sekiya, H; Takachio, O; Takeda, A; Tasaka, S; Yamashita, M; Yang, B S; Kim, N Y; Kim, Y D; Itow, Y; Kegasa, R; Kobayashi, K; Masuda, K; Fushimi, K; Martens, K; Suzuki, Y; Fujita, R; Hosokawa, K; Miuchi, K; Oka, N; Onishi, Y; Takeuchi, Y; Kim, Y H; Lee, J S; Lee, K B; Lee, M K; Fukuda, Y; Nishijima, K; Nakamura, S

    2016-01-01

    We report the measurement of the emission time profile of scintillation from gamma-ray induced events in the XMASS-I 832 kg liquid xenon scintillation detector. Decay time constant was derived from a comparison of scintillation photon timing distributions between the observed data and simulated samples in order to take into account optical processes such as absorption and scattering in liquid xenon. Calibration data of radioactive sources, $^{55}$Fe, $^{241}$Am, and $^{57}$Co were used to obtain the decay time constant. The decay time constant $\\tau$ increased from 27.9 ns to 37.0 ns as the gamma-ray energy increased from 5.9 keV to 122 keV. The accuracy of the measurement was better than 1.5 ns at all energy levels. Furthermore, a fast decay component with $\\tau \\sim$2 ns was necessary to reproduce data. The obtained data almost reproduced previously reported data and extended it to the lower energy region relevant to the direct dark matter search.

  8. A measurement of the time profile of scintillation induced by low energy gamma-rays in liquid xenon with the XMASS-I detector

    Science.gov (United States)

    Takiya, H.; Abe, K.; Hiraide, K.; Ichimura, K.; Kishimoto, Y.; Kobayashi, K.; Kobayashi, M.; Moriyama, S.; Nakahata, M.; Norita, T.; Ogawa, H.; Sekiya, H.; Takachio, O.; Takeda, A.; Tasaka, S.; Yamashita, M.; Yang, B. S.; Kim, N. Y.; Kim, Y. D.; Itow, Y.; Kegasa, R.; Kobayashi, K.; Masuda, K.; Fushimi, K.; Martens, K.; Suzuki, Y.; Fujita, R.; Hosokawa, K.; Miuchi, K.; Oka, N.; Onishi, Y.; Takeuchi, Y.; Kim, Y. H.; Lee, J. S.; Lee, K. B.; Lee, M. K.; Fukuda, Y.; Nishijima, K.; Nakamura, S.

    2016-10-01

    We report the measurement of the emission time profile of scintillation from gamma-ray induced events in the XMASS-I 832 kg liquid xenon scintillation detector. Decay time constant was derived from a comparison of scintillation photon timing distributions between the observed data and simulated samples in order to take into account optical processes such as absorption and scattering in liquid xenon. Calibration data of radioactive sources, 55Fe, 241Am, and 57Co were used to obtain the decay time constant. Assuming two decay components, τ1 and τ2, the decay time constant τ2 increased from 27.9 ns to 37.0 ns as the gamma-ray energy increased from 5.9 keV to 122 keV. The accuracy of the measurement was better than 1.5 ns at all energy levels. A fast decay component with τ1 ∼ 2 ns was necessary to reproduce data. Energy dependencies of τ2 and the fraction of the fast decay component were studied as a function of the kinetic energy of electrons induced by gamma-rays. The obtained data almost reproduced previously reported results and extended them to the lower energy region relevant to direct dark matter searches.

  9. Direct WIMP searches with XENON100 and XENON1T

    Directory of Open Access Journals (Sweden)

    Davide Ferella Alfredo

    2015-01-01

    Full Text Available The XENON100 experiment is the second phase of the XENON direct Dark Matter search program. It consists of an ultra-low background double phase (liquid-gas xenon filled time projection chamber with a total mass of 161 kg (62 in the target region and 99 in the active shield, installed at the Laboratori Nazionali del Gran Sasso (LNGS. Here the results from the 224.6 live days of data taken between March 2011 and April 2012 are reported. The experiment set one of the most stringent limits on the WIMP-nucleon spin-independent cross section to date (2 × 10−45 cm2 for a 55 Gev/c2 WIMP mass at 90 % confidence level and the most stringent on the spin-dependent WIMP-neutron interaction (3.5 × 10−40 for a 45 GeV/c2 WIMP mass. With the same dataset, XENON100 excludes also solar axion coupling to electrons at gAe > 7.7 × 10−12 for a mass of mAxion 1 × 10−12 at a mass range of mAxion = 5−10 keV/c2 (both 90 % C.L.. Moreover an absolute spectral comparison between simulated and measured nuclear recoil distributions of light and charge signals from a 241AmBe source demonstrates a high level of detector and systematics understanding. Finally, the third generation of the XENON experiments, XENON1T, is the first tonne scale direct WIMP search experiment currently under construction. The commissioning phase of XENON1T is expected to start in early 2015 followed, a few months after, by the first science run. The experiment will reach sensitivities on the WIMP-nucleon spin-independent cross section down to 2 ×10−47 cm2 after two years of data taking.

  10. Relaxation channels of multi-photon excited xenon clusters

    Energy Technology Data Exchange (ETDEWEB)

    Serdobintsev, P. Yu.; Melnikov, A. S. [Institute of Nanobiotechnologies, Peter the Great St.Petersburg Polytechnic University, Saint Petersburg 195251 (Russian Federation); Department of Physics, St. Petersburg State University, Saint Petersburg 198904 (Russian Federation); Rakcheeva, L. P., E-mail: lida@nanobio.spbstu.ru; Murashov, S. V.; Khodorkovskii, M. A. [Institute of Nanobiotechnologies, Peter the Great St.Petersburg Polytechnic University, Saint Petersburg 195251 (Russian Federation); Lyubchik, S. [REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2829-516 (Portugal); Timofeev, N. A.; Pastor, A. A. [Department of Physics, St. Petersburg State University, Saint Petersburg 198904 (Russian Federation)

    2015-09-21

    The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

  11. The Impact of Photon Flight Path on S1 Pulse Shape Analysis in Liquid Xenon Two-phase Detectors

    CERN Document Server

    Moongweluwan, M

    2015-01-01

    The LUX dark matter search experiment is a 350 kg dual-phase xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. The success of two-phase xenon detectors for dark matter searches relies on their ability to distinguish electron recoil (ER) background events from nuclear recoil (NR) signal events. Typically, the NR-ER discrimination is obtained from the ratio of the electroluminescence light (S2) to the prompt scintillation light (S1). Analysis of the S1 pulse shape is an additional discrimination technique that can be used to distinguish NR from ER. Pulse-shape NR-ER discrimination can be achieved based on the ratio of the de-excitation processes from singlet and triplet states that generate the S1. The NR S1 is dominated by the de-excitation process from singlet states with a time constant of about 3 ns while the ER S1 is dominated by the de-excitation process from triplet states with a time constant of about 24 ns. As the size of the detectors ...

  12. Chromatographic separation of radioactive noble gases from xenon

    CERN Document Server

    Akerib, D S; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Bramante, R; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chiller, A A; Chiller, C; Coffey, T; Currie, A; Cutter, J E; Davison, T J R; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Ihm, M; Jacobsen, R G; Ji, W; Kamdin, K; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Manalaysay, A; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O'Sullivan, K; Oliver-Mallory, K C; Palladino, K J; Pease, E K; Pech, K; Phelps, P; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Yazdani, K; Young, S K; Zhang, C

    2016-01-01

    The Large Underground Xenon (LUX) experiment operates at the Sanford Underground Research Facility to detect nuclear recoils from the hypothetical Weakly Interacting Massive Particles (WIMPs) on a liquid xenon target. Liquid xenon typically contains trace amounts of the noble radioactive isotopes $^{85}$Kr and $^{39}$Ar that are not removed by the {\\em in situ} gas purification system. The decays of these isotopes at concentrations typical of research-grade xenon would be a dominant background for a WIMP search exmperiment. To remove these impurities from the liquid xenon, a chromatographic separation system based on adsorption on activated charcoal was built. 400\\,kg of xenon was processed, reducing the average concentration of krypton from 130\\,ppb to 3.5\\,ppt as measured by a cold-trap assisted mass spectroscopy system. A 50 kg batch spiked to 0.001 g/g of krypton was processed twice and reduced to an upper limit of 0.2 ppt.

  13. Radon screening for XENON1T

    Energy Technology Data Exchange (ETDEWEB)

    Lindemann, Sebastian [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2015-07-01

    Radon with its isotope {sup 222}Rn is one of the dominant sources of internal background in liquid xenon detectors searching for low energetic rare events like WIMP-nucleon scattering. In my talk I briefly review the problem posed by {sup 222}Rn and motivate the screening strategy followed by XENON1T. I introduce the radon emanation technique making use of ultra low background proportional counters and present selected results obtained during the design and construction phases of XENON1T. Finally, I sketch advances in radon emanation assay techniques and give a short outlook on upcoming measurements.

  14. Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    Leeuwen, van Suze M.; Tan, BoonHua; Grijpma, Dirk W.; Feijen, J.; Karst, Uwe

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an -caprolactone (CL

  15. Characterization of the chemical composition of a block copolymer by liquid chromatography/mass spectrometry using atmospheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    van Leeuwen, Suze M.; Tan, BoonHua; Grijpma, Dirk W.; Fejen, Jan; Karst, Uwe

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an epsilon-caprolact

  16. Characterization of the chemical composition of a block copolymer by liquid chromotography/mass spectroscopy using atomspheric pressure chemical ionization and electrospray ionization

    NARCIS (Netherlands)

    van Leeuwen, S.M.; Tan, B.H.; Grijpma, Dirk W.; Feijen, Jan; Karst, U.

    2007-01-01

    Liquid chromatography/mass spectrometry (LC/MS) with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in the positive and negative ion modes was used for the characterization of a block copolymer consisting of methoxy poly(ethylene oxide) (mPEO), an -caprolactone

  17. Detection of scintillation light in coincidence with ionizing tracks in a liquid argon time projection chamber

    CERN Document Server

    Cennini, P; Rubbia, Carlo; Sergiampietri, F; Bueno, A G; Campanelli, M; Goudsmit, P; Rubbia, André; Periale, L; Suzuki, S; Chen, C; Chen, Y; He, K; Huang, X; Li, Z; Lu, F; Ma, J; Xu, G; Xu, Z; Zhang, C; Zhang, Q; Zheng, S; Cavanna, F; Mazza, D; Piano Mortari, G; Petrera, S; Rossi, C; Mannocchi, G; Picchi, P; Arneodo, F; De Mitri, I; Palamara, O; Cavalli, D; Ferrari, A; Sala, P R; Borio di Tigliole, A A; Cesana, A; Terrani, M; Zavattari, C; Baibusinov, S; Bettini, A; Carpanese, C; Centro, Sandro; Favaretto, D; Pascoli, D; Pepato, Adriano; Pietropaolo, F; Ventura, Sandro; Benetti, P; Calligarich, E; Campo, S; Coco, S; Dolfini, R; Ghedi, B; Gigli-Berzolari, A; Mauri, F; Mazzone, L; Montanari, C; Piazzoli, A; Rappoldi, A; Raselli, G L; Rebuzzi, D; Rossella, M; Scannicchio, D A; Torre, P; Vignoli, C; Cline, D; Otwinowski, S; Wang, H; Woo, J

    1999-01-01

    A system to detect light from liquid argon scintillation has been implemented in a small, ICARUS-like, liquid argon time projection chamber. The system, which uses a VUV-sensitive photomultiplier to collect the light, has recorded many ionizing tracks from cosmic-rays in coincidence with scintillation signals. Our measurements demonstrate that scintillation light detection can provide an effective method for absolute time measurement of events and eventually a useful trigger signal. (19 refs).

  18. Combining Laser Ablation/Liquid Phase Collection Surface Sampling and High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikova, Olga S [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2011-01-01

    This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid phase sample collection method for surface sampling and ionization with subsequent mass spectral analysis. A commercially available autosampler was adapted to produce a liquid droplet at the end of the syringe injection needle while in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collection was followed by either flow injection or a high performance liquid chromatography (HPLC) separation of the extracted components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the analytical utility of this coupling, thin films of a commercial ink sample containing rhodamine 6G and of mixed isobaric rhodamine B and 6G dyes on glass microscope slides were analyzed. The flow injection and HPLC/ESI-MS analysis revealed successful laser ablation, capture and, with HPLC, the separation of the two compounds. The ablated circular area was about 70 m in diameter for these experiments. The spatial sampling resolution afforded by the laser ablation, as well as the ability to use sample processing methods like HPLC between the sample collection and ionization steps, makes this combined surface sampling/ionization technique a highly versatile analytical tool.

  19. Simultaneous quantitative analysis of metabolites using ion-pair liquid chromatography-electrospray ionization mass spectrometry

    NARCIS (Netherlands)

    Coulier, L.; Bas, R.; Jespersen, S.; Verheij, E.; Werf, M.J. van der; Hankemeier, T.

    2006-01-01

    We have developed an analytical method, consisting of ion-pair liquid chromatography coupled to electrospray ionization mass spectrometry (IP-LC-ESI-MS), for the simultaneous quantitative analysis of several key classes of polar metabolites, like nucleotides, coenzyme A esters, sugar nucleotides, an

  20. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  1. X-ray ionization yields and energy spectra in liquid argon

    CERN Document Server

    Bondar, A; Dolgov, A; Shekhtman, L; Sokolov, A

    2015-01-01

    The main purpose of this work is to provide reference data on X-ray ionization yields and energy spectra in liquid Ar to the studies in the field of Cryogenic Avalanche Detectors (CRADs) for rare-event experiments, based on noble-gas liquids. We present the results of two related researches. First, the X-ray recombination coefficients in the energy range of 10-1000 keV and ionization yields at different electric fields are determined in liquid Ar, based on the results of a dedicated experiment. Second, the energy spectra of pulsed X-rays in liquid Ar in the energy range of 15-40 keV, obtained in given experiments including that with the two-phase CRAD, are interpreted and compared to those calculated using a dedicated computer program, to correctly determine the incident X-ray energy. The X-ray recombination coefficients and ionization yields have for the first time been presented for liquid Ar in systematic way.

  2. X-ray ionization yields and energy spectra in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Bondar, A.; Buzulutskov, A. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Dolgov, A. [Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Shekhtman, L.; Sokolov, A. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2016-04-21

    The main purpose of this work is to provide reference data on X-ray ionization yields and energy spectra in liquid Ar to the studies in the field of Cryogenic Avalanche Detectors (CRADs) for rare-event and other experiments, based on liquid Ar detectors. We present the results of two related researches. First, the X-ray recombination coefficients in the energy range of 10–1000 keV and ionization yields at different electric fields, between 0.6 and 2.3 kV/cm, are determined in liquid Ar based on the results of a dedicated experiment. Second, the energy spectra of pulsed X-rays in liquid Ar in the energy range of 15−40 keV, obtained in given experiments including that with the two-phase CRAD, are interpreted and compared to those calculated using a computer program, to correctly determine the absorbed X-ray energy. The X-ray recombination coefficients and ionization yields have for the first time been presented for liquid Ar in systematic way.

  3. Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Shiina Tatsuo

    2016-01-01

    Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

  4. Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon

    CERN Document Server

    Cao, H; Avetisyan, R; Back, H O; Cocco, A G; DeJongh, F; Fiorillo, G; Galbiati, C; Grandi, L; Guardincerri, Y; Kendziora, C; Lippincott, W H; Love, C; Lyons, S; Manenti, L; Martoff, C J; Meng, Y; Montanari, D; Mosteiro, P; Olvitt, D; Pordes, S; Qian, H; Rossi, B; Saldanha, R; Sangiorgio, S; Siegl, K; Strauss, S Y; Tan, W; Tatarowicz, J; Walker, S; Wang, H; Watson, A W; Westerdale, S; Yoo, J

    2014-01-01

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation and ionization yields for nuclear recoils with energies from 10.3 to 57.2 keV and for applied electric fields from 0 to 1000 V/cm. We also report the observation of an anti-correlation between scintillation and ionization from nuclear recoils, which is similar to the anti-correlation between scintillation and ionization from electron recoils. A comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field yielded a first evidence of sensitivity to direct...

  5. A numerical model of initial recombination for high-LET irradiation: Application to liquid-filled ionization chambers

    Science.gov (United States)

    Aguiar, P.; Pardo-Montero, J.

    2016-02-01

    In this paper we present a numerical model of initial recombination in media irradiated with high linear energy transfer (LET) ions, which relies on an amorphous track model of ionization of high LET particles, and diffusion, drift and recombination of ionized charge carriers. The model has fundamental applications for the study of recombination in non-polar liquids, as well as practical ones, like in modelling hadrontherapy dosimetry with ionization chambers. We have used it to study the response of liquid-filled ionization chambers to hadrontherapy beams: dependence of initial recombination on ion species, energy and applied external electric field.

  6. Ambient desorption/ionization mass spectrometry using a liquid sampling-atmospheric glow discharge (LS-APGD) ionization source.

    Science.gov (United States)

    Marcus, R Kenneth; Burdette, Carolyn Q; Manard, Benjamin T; Zhang, Lynn X

    2013-10-01

    A novel approach to ambient desorption/ionization mass spectrometry (ADI-MS) is described, based on a recently developed liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source. The device is essentially unmodified relative to its implementation in elemental mass spectrometry, where the operational space is characterized by low operation power (LS-APGD source is mounted onto the source interface of a Thermo Finnigan LCQ Advantage Max quadrupole ion trap mass spectrometer without modifications to the instrument faceplate or ion optics. Described here is the initial evaluation of the roles of source geometry and working parameters, including electrolytic solution composition and plasma current, on the response of caffeine residues, with preliminary limits of detection based on the relative standard deviation of the spectral background suggested to be on the 10-pg level. Demonstrative spectra are presented for green tea extracts and raw leaves, coffee beans, a dried (raw) tobacco leaf, an analgesic tablet, and paper currency. Versatility is further revealed through the determination of components in common cigarette smoke. In each case, the spectra are characterized by (M + H)(+) species of the expected constituents. The capacity for a single source to perform both in solution and particulate elemental analysis (as shown previously) and ADI of molecular species is unique in the realm of mass spectrometry.

  7. Electron drift in a large scale solid xenon

    CERN Document Server

    Yoo, J

    2015-01-01

    A study of charge drift in a large scale optically transparent solid xenon is reported. A pulsed high power xenon light source is used to liberate electrons from a photocathode. The drift speeds of the electrons are measured using a 8.7\\,cm long electrode in both the liquid and solid phase of xenon. In the liquid phase (163\\,K), the drift speed is 0.193 $\\pm$ 0.003 cm/$\\mu$s while the drift speed in the solid phase (157\\,K) is 0.397 $\\pm$ 0.006 cm/$\\mu$s at 900 V/cm over 8.0\\,cm of uniform electric fields. Therefore, it is demonstrated that a factor two faster electron drift speed in solid phase xenon compared to that in liquid in a large scale solid xenon.

  8. Dissociative ionization of liquid water induced by vibrational overtone excitation

    Energy Technology Data Exchange (ETDEWEB)

    Natzle, W.C.

    1983-03-01

    Photochemistry of vibrationally activated ground electronic state liquid water to produce H/sup +/ and OH/sup -/ ions has been initiated by pulsed, single-photon excitation of overtone and combination transitions. Transient conductivity measurements were used to determine quantum yields as a function of photon energy, isotopic composition, and temperature. The equilibrium relaxation rate following perturbation by the vibrationally activated reaction was also measured as a function of temperature reaction and isotopic composition. In H/sub 2/O, the quantum yield at 283 +- 1 K varies from 2 x 10/sup -9/ to 4 x 10/sup -5/ for wave numbers between 7605 and 18140 cm/sup -1/. In D/sub 2/O, the dependence of quantum yield on wavelength has the same qualitative shape as for H/sub 2/O, but is shifted to lower quantum yields. The position of a minimum in the quantum yield versus hydrogen mole fraction curve is consistent with a lower quantum yield for excitation of HOD in D/sub 2/O than for excitation of D/sub 2/O. The ionic recombination distance of 5.8 +- 0.5 A is constant within experimental error with temperature in H/sub 2/O and with isotopic composition at 25 +- 1/sup 0/C.

  9. First axion results from the XENON100 experiment

    NARCIS (Netherlands)

    Aprile, E.; et al., [Unknown; Alfonsi, M.; Colijn, A.P.; Decowski, M.P.

    2014-01-01

    We present the first results of searches for axions and axionlike particles with the XENON100 experiment. The axion-electron coupling constant, gAe, has been probed by exploiting the axioelectric effect in liquid xenon. A profile likelihood analysis of 224.6 live days × 34-kg exposure has shown no e

  10. The XENON1T Dark Matter Search Experiment

    CERN Document Server

    Aprile, Elena

    2012-01-01

    The worldwide race towards direct dark matter detection in the form of Weakly Interacting Massive Particles (WIMPs) has been dramatically accelerated by the remarkable progress and evolution of liquid xenon time projection chambers (LXeTPCs). With a realistic discovery potential, XENON100 has already reached a sensitivity of $7\\times10^{-45}\\,\

  11. Field-dependent molecular ionization and excitation energies: Implications for electrically insulating liquids

    Directory of Open Access Journals (Sweden)

    N. Davari

    2014-03-01

    Full Text Available The molecular ionization potential has a relatively strong electric-field dependence as compared to the excitation energies which has implications for electrical insulation since the excited states work as an energy sink emitting light in the UV/VIS region. At some threshold field, all the excited states of the molecule have vanished and the molecule is a two-state system with the ground state and the ionized state, which has been hypothesized as a possible origin of different streamer propagation modes. Constrained density-functional theory is used to calculate the field-dependent ionization potential of different types of molecules relevant for electrically insulating liquids. The low singlet-singlet excitation energies of each molecule have also been calculated using time-dependent density functional theory. It is shown that low-energy singlet-singlet excitation of the type n → π* (lone pair to unoccupied π* orbital has the ability to survive at higher fields. This type of excitation can for example be found in esters, diketones and many color dyes. For alkanes (as for example n-tridecane and cyclohexane on the other hand, all the excited states, in particular the σ → σ* excitations vanish in electric fields higher than 10 MV/cm. Further implications for the design of electrically insulating dielectric liquids based on the molecular ionization potential and excitation energies are discussed.

  12. Observation and applications of single-electron charge signals in the XENON100 experiment

    NARCIS (Netherlands)

    Aprile, E.; et al., [Unknown; Alfonsi, M.; Colijn, A.P.; Decowski, M.P.

    2014-01-01

    The XENON100 dark matter experiment uses liquid xenon in a time projection chamber (TPC) to measure xenon nuclear recoils resulting from the scattering of dark matter weakly interacting massive particles (WIMPs). In this paper, we report the observation of single-electron charge signals which are no

  13. The next generation dark matter hunter: XENON1T status and perspective

    Directory of Open Access Journals (Sweden)

    Rizzo A.

    2016-01-01

    Full Text Available The XENON Dark Matter Experiment has been ongoing at LNGS since 2005 with the goal of searching for dark matter WIMPs with liquid xenon as target and detector material. With detectors of increasing target mass and decreasing background, the XENON program has achieved competitive limits on WIMP-nucleon interaction couplings, but also on axions and axion like particles. With the start of the next generation experiment, XENON1T expected in 2015, XENON Dark Matter Experiment will continue to lead field of dark matter direct detection. XENON1T will be the first experiment to use multi-tons of liquid xenon in a time projection chamber and is designed to achieve two orders of magnitude higher sensitivity than the current best limits. I will review the status of construction and the scientific goals of XENON1T.

  14. Radon depletion in xenon boil-off gas

    OpenAIRE

    Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T. Marrodán; Simgen, H.

    2016-01-01

    An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of $^{222}$Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of $\\gtrsim 4$ for the $^{222}$Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based $\\alpha$-detector and miniaturized proportional counters are used to detect the radon. As the rado...

  15. Measurement of scintillation and ionization yield and scintillation pulse shape from nuclear recoils in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Cao, H.; Alexander, T.; Aprahamian, A.; Avetisyan, R.; Back, H. O.; Cocco, A. G.; DeJongh, F.; Fiorillo, G.; Galbiati, C.; Grandi, L.; Guardincerri, Y.; Kendziora, C.; Lippincott, W. H.; Love, C.; Lyons, S.; Manenti, L.; Martoff, C. J.; Meng, Y.; Montanari, D.; Mosteiro, P.; Olvitt, D.; Pordes, S.; Qian, H.; Rossi, B.; Saldanha, R.; Sangiorgio, S.; Siegl, K.; Strauss, S. Y.; Tan, W.; Tatarowicz, J.; Walker, S.; Wang, H.; Watson, A. W.; Westerdale, S.; Yoo, J.

    2015-05-01

    We have measured the scintillation and ionization yield of recoiling nuclei in liquid argon as a function of applied electric field by exposing a dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy pulsed narrow band neutron beam produced at the Notre Dame Institute for Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged to detect and identify neutrons scattered in the TPC and to select the energy of the recoiling nuclei. We report measurements of the scintillation yields for nuclear recoils with energies from 10.3 to 57.3 keV and for median applied electric fields from 0 to 970 V / cm . For the ionization yields, we report measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486 V / cm . We also report the observation of an anticorrelation between scintillation and ionization from nuclear recoils, which is similar to the anticorrelation between scintillation and ionization from electron recoils. Assuming that the energy loss partitions into excitons and ion pairs from 83 m Kr internal conversion electrons is comparable to that from 207 Bi conversion electrons, we obtained the numbers of excitons ( N ex ) and ion pairs ( N i ) and their ratio ( N ex / N i ) produced by nuclear recoils from 16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in LAr-TPC signals due to columnar recombination, a comparison of the light and charge yield of recoils parallel and perpendicular to the applied electric field is presented for the first time.

  16. Plasma lipid analysis by hydrophilic interaction liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Sonomura, Kazuhiro; Kudoh, Shinobu; Sato, Taka-Aki; Matsuda, Fumihiko

    2015-06-01

    A novel method for the analysis of endogenous lipids and related compounds was developed employing hydrophilic interaction liquid chromatography with electrospray ionization tandem mass spectrometry. A hydrophilic interaction liquid chromatography with carbamoyl stationary phase achieved clear separation of phosphatidylcholine, lysophosphatidylcholine, sphingomyelin, ceramide, and mono-hexsosyl ceramide groups with good peak area repeatability (RSD% 0.99). The established method was applied to human plasma assays and a total of 117 endogenous lipids were successfully detected and reproducibly identified. In addition, we investigated the simultaneous detection of small polar metabolites such as amino and organic acids co-existing in the same biological samples processed in a single analytical run with lipids. Our results show that hydrophilic interaction liquid chromatography is a useful tool for human plasma lipidome analysis and offers more comprehensive metabolome coverage.

  17. Electron impact ionization of water molecules in ice and liquid phases

    Energy Technology Data Exchange (ETDEWEB)

    Joshipura, K N [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388120 (India); Gangopadhyay, Sumona [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388120 (India); Limbachiya, C G [P S Science College, Kadi (N.G.) 382 715 (India); Vinodkumar, Minaxi [V P and R P T P Science College, Vallabh Vidyanagar-388 120 (India)

    2007-09-15

    Electron scattering processes in ice or water are known to occur in natural as well as man-made systems. But the processes are difficult to investigate in theory or in laboratory. We present our calculations on total ionization cross section (Q{sub ion}) for collisions of electrons with H{sub 2}O molecules in condensed matter (ice and liquid) forms, at impact energies from ionization threshold to 1000 eV, extendable to about 1 MeV. Our theoretical method determines the total inelastic cross section (Q{sub inel}) of electron impact on H{sub 2}O (ice), by starting with the complex scattering potential partial wave formalism. Reasonable approximations are invoked to project out the ionization cross section of H{sub 2}O molecule in ice (or liquid) form by using the Q{sub inel} as an input. Properties of the condensed phase H{sub 2}O are incorporated together with bulk screening effects in the scattering echanism. Due to medium effects, the present Q{sub ion} are found to be lower than the corresponding values for H{sub 2}O in free or gaseous state. Macroscopic cross sections and electron mean free paths for the bulk medium are also calculated. This study has potential applications in radiation biology as well as chemistry and in planetary science and astrophysics.

  18. Scintillation luminescence for high-pressure xenon gas

    Science.gov (United States)

    Kobayashi, S.; Hasebe, N.; Igarashi, T.; Kobayashi, M.-N.; Miyachi, T.; Miyajima, M.; Okada, H.; Okudaira, O.; Tezuka, C.; Yokoyama, E.; Doke, T.; Shibamura, E.; Dmitrenko, V. V.; Ulin, S. E.; Vlasik, K. F.

    2004-09-01

    Scintillation and ionization yields in xenon gas for 5.49MeV alpha-particles were measured in the range of pressure from 0.35 to 3.7MPa and the electric field strength (E) over the number density of xenon atoms (N), E/N from 0 to 5×10-18Vcm2. When our data are normalized at the data point measured by Saito et al., the number of scintillation photons is 2.3×105 while the number of ionization electrons is 2.0×105 at 2.6MPa and at 3.7×10-18Vcm2. The scintillation and ionization yields of xenon doped with 0.2% hydrogen, High-Pressure Xenon gas[H2-0.2%], at 2.6MPa was also measured. Scintillation yield of the Xe-H2 mixture gas is 80% as high as that of pure xenon. It is found that the scintillation yield is luminous enough to generate a trigger pulse of the high-pressure xenon time projection chamber, which is expected as a promising MeV Compton gamma-ray camera.

  19. Detection of Posaconazole by Surface-Assisted Laser Desorption/Ionization Mass Spectrometry with Dispersive Liquid-Liquid Microextraction

    Science.gov (United States)

    Lin, Sheng-Yu; Chen, Pin-Shiuan; Chang, Sarah Y.

    2015-03-01

    A simple, rapid, and sensitive method for the detection of posaconazole using dispersive liquid-liquid microextraction (DLLME) coupled to surface-assisted laser desorption/ionization mass spectrometric detection (SALDI/MS) was developed. After the DLLME, posaconazole was detected using SALDI/MS with colloidal gold and α-cyano-4-hydroxycinnamic acid (CHCA) as the co-matrix. Under optimal extraction and detection conditions, the calibration curve, which ranged from 1.0 to 100.0 nM for posaconazole, was observed to be linear. The limit of detection (LOD) at a signal-to-noise ratio of 3 was 0.3 nM for posaconazole. This novel method was successfully applied to the determination of posaconazole in human urine samples.

  20. A liquid-filled ionization chamber for high precision relative dosimetry.

    Science.gov (United States)

    González-Castaño, D M; Gómez, F; Brualla, L; Roselló, J V; Planes, D; Sánchez, M; Pombar, M

    2011-04-01

    Radiosurgery and intensity modulated radiation therapy (IMRT) treatments are based on the delivery of narrow and/or irregularly shaped megavoltage photon beams. This kind of beams present both lack of charged particle equilibrium and steep dose gradients. Quality assurance (QA) measurements involved in these techniques must therefore be carried out with a dosimeter featuring high small volume. In order to obtain a good signal to noise ratio, a relatively dense material is needed as active medium. Non-polar organic liquids were proposed as active mediums with both good tissue equivalence and showing high signal to noise ratio. In this work, a liquid-filled ionization chamber is presented. Some results acquired with this detector in relative dosimetry are studied and compared with results obtained with unshielded diode. Medium-term stability measurements were also carried out and its results are shown. The liquid-filled ionization chamber presented here shows its ability to perform profile measurements and penumbrae determination with excellent accuracy. The chamber features a proper signal stability over the period studied.

  1. Application of the two-dose-rate method for general recombination correction for liquid ionization chambers in continuous beams

    Science.gov (United States)

    Andersson, Jonas; Tölli, Heikki

    2011-01-01

    A method to correct for the general recombination losses for liquid ionization chambers in continuous beams has been developed. The proposed method has been derived from Greening's theory for continuous beams and is based on measuring the signal from a liquid ionization chamber and an air filled monitor ionization chamber at two different dose rates. The method has been tested with two plane parallel liquid ionization chambers in a continuous radiation x-ray beam with a tube voltage of 120 kV and with dose rates between 2 and 13 Gy min-1. The liquids used as sensitive media in the chambers were isooctane (C8H18) and tetramethylsilane (Si(CH3)4). The general recombination effect was studied using chamber polarizing voltages of 100, 300, 500, 700 and 900 V for both liquids. The relative standard deviation of the results for the collection efficiency with respect to general recombination was found to be a maximum of 0.7% for isooctane and 2.4% for tetramethylsilane. The results are in excellent agreement with Greening's theory for collection efficiencies over 90%. The measured and corrected signals from the liquid ionization chambers used in this work are in very good agreement with the air filled monitor chamber with respect to signal to dose linearity.

  2. Application of the two-dose-rate method for general recombination correction for liquid ionization chambers in continuous beams

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Jonas; Toelli, Heikki, E-mail: jonas.andersson@radfys.umu.se [Department of Radiation Sciences, Radiation Physics, Umeaa University, SE-901 85 Umeaa (Sweden)

    2011-01-21

    A method to correct for the general recombination losses for liquid ionization chambers in continuous beams has been developed. The proposed method has been derived from Greening's theory for continuous beams and is based on measuring the signal from a liquid ionization chamber and an air filled monitor ionization chamber at two different dose rates. The method has been tested with two plane parallel liquid ionization chambers in a continuous radiation x-ray beam with a tube voltage of 120 kV and with dose rates between 2 and 13 Gy min{sup -1}. The liquids used as sensitive media in the chambers were isooctane (C{sub 8}H{sub 18}) and tetramethylsilane (Si(CH{sub 3}){sub 4}). The general recombination effect was studied using chamber polarizing voltages of 100, 300, 500, 700 and 900 V for both liquids. The relative standard deviation of the results for the collection efficiency with respect to general recombination was found to be a maximum of 0.7% for isooctane and 2.4% for tetramethylsilane. The results are in excellent agreement with Greening's theory for collection efficiencies over 90%. The measured and corrected signals from the liquid ionization chambers used in this work are in very good agreement with the air filled monitor chamber with respect to signal to dose linearity.

  3. Fully Automated Laser Ablation Liquid Capture Sample Analysis using NanoElectrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Matthias [ORNL; Ovchinnikova, Olga S [ORNL; Van Berkel, Gary J [ORNL

    2014-01-01

    RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system. RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant

  4. Electron impact ionization of liquid and gaseous water: a single-center partial-wave approach

    Energy Technology Data Exchange (ETDEWEB)

    Champion, C [Universite Paul Verlaine-Metz, Laboratoire de Physique Moleculaire et des Collisions, ICPMB (FR CNRS 2843), Institut de Physique, 1 bd Arago, 57078 Metz Cedex 3 (France)], E-mail: champion@univ-metz.fr

    2010-01-07

    In this work, we report a unified methodology to express the molecular wavefunctions of water in both vapor and liquid phases by means of a single-center approach. These latter are then used as input data in a theoretical treatment-previously published and successfully tested-for describing the water ionization process in the first Born approximation (Champion et al 2006 Phys. Rev. A 73 012717). The multi-differential and total cross sections also obtained are reported for the two thermodynamical phases investigated and compared to the rare existing experimental and theoretical data.

  5. Direct Dark Matter search with XENON100

    Directory of Open Access Journals (Sweden)

    Orrigo S.E.A.

    2016-01-01

    Full Text Available The XENON100 experiment is the second phase of the XENON program for the direct detection of the dark matter in the universe. The XENON100 detector is a two-phase Time Projection Chamber filled with 161 kg of ultra pure liquid xenon. The results from 224.6 live days of dark matter search with XENON100 are presented. No evidence for dark matter in the form of WIMPs is found, excluding spin-independent WIMP-nucleon scattering cross sections above 2 × 10−45 cm2 for a 55 GeV/c2 WIMP at 90% confidence level (C.L.. The most stringent limit is established on the spin-dependent WIMP-neutron interaction for WIMP masses above 6 GeV/c2, with a minimum cross section of 3.5 × 10−40 cm2 (90% C.L. for a 45 GeV/c2 WIMP. The same dataset is used to search for axions and axion-like-particles. The best limits to date are set on the axion-electron coupling constant for solar axions, gAe < 7.7 × 10−12 (90% C.L., and for axion-like-particles, gAe < 1 × 10−12 (90% C.L. for masses between 5 and 10 keV/c2.

  6. Cosmogenic activation of xenon and copper

    Energy Technology Data Exchange (ETDEWEB)

    Baudis, Laura; Kish, Alexander; Piastra, Francesco [University of Zuerich, Department of Physics, Zuerich (Switzerland); Schumann, Marc [University of Bern, Albert Einstein Center for Fundamental Physics, Bern (Switzerland)

    2015-10-15

    Rare event search experiments using liquid xenon as target and detection medium require ultra-low background levels to fully exploit their physics potential. Cosmic ray induced activation of the detector components and, even more importantly, of the xenon itself during production, transportation and storage at the Earth's surface, might result in the production of radioactive isotopes with long half-lives, with a possible impact on the expected background. We present the first dedicated study on the cosmogenic activation of xenon after 345 days of exposure to cosmic rays at the Jungfraujoch research station at 3470 m above sea level, complemented by a study of copper which has been activated simultaneously. We have directly observed the production of {sup 7}Be, {sup 101}Rh, {sup 125}Sb, {sup 126}I and {sup 127}Xe in xenon, out of which only {sup 125}Sb could potentially lead to background for a multi-ton scale dark matter search. The production rates for five out of eight studied radioactive isotopes in copper are in agreement with the only existing dedicated activation measurement, while we observe lower rates for the remaining ones. The specific saturation activities for both samples are also compared to predictions obtained with commonly used software packages, where we observe some underpredictions, especially for xenon activation. (orig.)

  7. Shock-tube measurements of the excitational cross-section in xenon-hydrogen mixture

    Energy Technology Data Exchange (ETDEWEB)

    Ezumi, Hiromichi (Hiroshima Denki Inst. of Tech. (Japan)); Kawamura, Masahiko; Gohda, Noriaki

    1984-02-01

    The Ionization relaxation and radiative-cooling processes behind shock wave in xenon with or without a small amount of hydrogen have been investigated using a quadrature interferometer technique at shock Mach numbers Msub(s)--13 and the initial pressure P/sub 1/=2.0 Torr. By adding a small amount of hydrogen (--0.5% of the initial pressure) to xenon, the ionization relaxation time was drastically reduced to about one-third of its pure xenon value. From the comparison between theoretical values based on the two-step ionization model and experimental data, the slope constants of excitational cross-section against relative kinetic energy between xenon atom-atom collisions and xenon-hydrogen atom-atom collisions were determined to be 1.8x10/sup -19/ cm/sup 2//eV and 9.0x10/sup -19/ cm/sup 2//eV, respectively.

  8. Radon depletion in xenon boil-off gas

    Energy Technology Data Exchange (ETDEWEB)

    Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T.M.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2017-03-15

    An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of {sup 222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of >or similar 4 for the {sup 222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α-detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10{sup -15} mol/mol level. (orig.)

  9. Radon depletion in xenon boil-off gas

    CERN Document Server

    Bruenner, S; Lindemann, S; Undagoitia, T Marrodán; Simgen, H

    2016-01-01

    An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of $^{222}$Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of $\\gtrsim 4$ for the $^{222}$Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based $\\alpha$-detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the $10^{-15}\\,$mol/mol level.

  10. Radon depletion in xenon boil-off gas

    Science.gov (United States)

    Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T. Marrodán; Simgen, H.

    2017-03-01

    An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of ^{222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of ≳ 4 for the ^{222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α -detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10^{-15} mol/mol level.

  11. Merits of online electrochemistry liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS).

    Science.gov (United States)

    Looi, Wen Donq; Brown, Blake; Chamand, Laura; Brajter-Toth, Anna

    2016-03-01

    A new online electrochemistry/liquid sample desorption electrospray ionization mass spectrometry (EC/LS DESI MS) system with a simple electrochemical thin-layer flow-through cell was developed and tested using N,N-dimethyl-p-phenylenediamine (DMPA) as a model probe. Although oxidation of DMPA is observed as a result of ionization of LS in positive ion mode LS DESI, application of voltage to the online electrochemical (EC) cell in EC/LS DESI MS increases yields of oxidation products. An advantage of LS DESI MS is its sensitivity in aqueous electrolyte solutions, which improves efficiency of electrochemical reactions in EC/LS DESI MS. In highly conductive low pH aqueous buffer solutions, oxidation efficiency is close to 100%. EC/ESI MS typically requires mixed aqueous/organic solvents and low electrolyte concentrations for efficient ionization in MS, limiting efficiency of electrochemistry online with MS. Independently, the results verify higher electrochemical oxidation efficiency during positive mode ESI than during LS DESI.

  12. Limits on GeV-scale WIMPs using charge signals in XENON100

    Science.gov (United States)

    Wall, Richard

    2014-03-01

    Various theoretical models and recent experimental results have led to growing interest in the search for WIMP-like dark matter in the mass range of a few GeV. One important class of detector used in this study is based on the liquid-gas, dual-phase Xenon time projection chamber (as in XENON100 and LUX). These detectors nominally use both scintillation (S1) and ionization (S2) signals to localize collision events in their sensitive volumes and thus reject background events, but it is known that the efficiency for detecting small S1 signals (such as are expected from a GeV-scale WIMP interaction) is much smaller than the efficiency for detecting an S2 from the same recoil. By removing the requirement of an observed S1 signal, one can thus effectively lower the energy threshold of the detector, and study GeV-scale WIMPs with greater sensitivity. With this in mind, we measure the rate of WIMP candidates in 225 live days of XENON100 data in events with small S2 signals (with or without an accompanying S1) and which pass other simple selection cuts optimized for GeV-scale WIMPs. This rate is then used to set a limit on the WIMP-nucleon cross-section for the mass range 1-10 GeV.

  13. Determination of ion recombination correction factors for a liquid ionization chamber in megavoltage photon beams

    Science.gov (United States)

    Choi, Sang Hyoun; Kim, Kum-Bae; Ji, Young Hoon; Kim, Chan Hyeong; Kim, Seonghoon; Huh, Hyun Do

    2015-05-01

    The aim of this study is to determine the ion recombination correction factor for a liquid ionization chamber in a high energy photon beam by using our experimental method. The ion recombination correction factors were determined by using our experimental method and were compared with theoretical and experimental methods proposed by using the theoretical method (Greening, Johansson) and the two-dose rate method in a cobalt beam and a high energy photon beam. In order to apply the liquid ionization chamber in a reference and small field dosimetry, we acquired the absorbed dose to water correction coefficient, the beam quality correction factor, and the influence quantities for the microLion chamber according to the TRS-398 protocol and applied the results to a high energy photon beam used in clinical fields. As a result, our experimental method for ion recombination in a cobalt beam agreed with the results from the heoretical method (Greening theory) better than it did with the results from the two-dose rate method. For high energy photon beams, the two-dose rate and our experimental methods were in good agreement, less than 2% deviation, while the theoretical general collection efficiency (Johansson et al.) deviated greatly from the experimental values. When we applied the factors for the absorbed dose to water measurement, the absorbed dose to water for the microLion chamber was in good agreement, within 1%, compared with the values for the PTW 30013 chamber in 6 and 10 MV Clinac iX and 6 and 15 MV Oncor impression. With these results, not only can the microLion ionization chamber be used to measure the absorbed dose to water in a reference condition, it can also be used to a the chamber for small, non-standard field dosimetry.

  14. Studies of Electron Avalanche Behavior in Liquid Argon

    CERN Document Server

    Kim, J G; Jackson, K H; Kadel, R W; Kadyk, J A; Peskov, Vladimir; Wenzel, W A

    2002-01-01

    Electron avalanching in liquid argon is being studied as a function of voltage, pressure, radiation intensity, and the concentrations of certain additives, especially xenon. The avalanches produced in an intense electric field at the tip of a tungsten needle are initiated by ionization from a moveable americium (241Am) gamma ray source. Photons from xenon excimers are detected as photomultiplier signals in coincidence with the current pulse from the needle. In pure liquid argon the avalanche behavior is erratic, but the addition of even a small amount of xenon (>100ppm) stabilizes the performance. Similar attempts with neon (30%) as an additive to argon have been unsuccessful. Tests with higher energy gamma rays (57Co) yield spectra and other performance characteristics quite similar to those using the 241Am source. Two types of signal pulses are commonly observed: a set of pulses that are sensitive to ambient pressure, and a set of somewhat smaller pulses that are not pressure dependent.

  15. Liquid chromatography/electrospray ionization mass spectrometric characterization of Harpagophytum in equine urine and plasma.

    Science.gov (United States)

    Colas, Cyril; Garcia, Patrice; Popot, Marie-Agnès; Bonnaire, Yves; Bouchonnet, Stéphane

    2006-01-01

    A method has been developed for the analysis and characterization in equine urine and plasma of iridoid glycosides: harpagide, harpagoside and 8-para-coumaroyl harpagide, which are the main active principles of Harpagophytum, a plant with antiinflammatory properties. The method involves liquid chromatography coupled with positive electrospray ionization mass spectrometry. The addition of sodium or lithium chloride instead of formic acid in the eluting solvent has been studied in order to enhance the signal and to modify the ion's internal energy. Fragmentation pathways and associated patterns are proposed for each analyte. A comparison of three types of mass spectrometer: a 3D ion trap, a triple quadrupole and a linear ion trap, has been conducted. The 3D ion trap was selected for drug screening analysis whereas the linear ion trap was retained for identification and quantitation analysis.

  16. Analysis of boronic acids by nano liquid chromatography-direct electron ionization mass spectrometry.

    Science.gov (United States)

    Flender, Cornelia; Leonhard, Peter; Wolf, Christian; Fritzsche, Matthias; Karas, Michael

    2010-05-15

    A new method, based on a direct-electron ionization (EI) interface, is presented for the analysis of compounds insufficiently amenable to usual MS methods. The instrumentation is composed of a nano liquid chromatograph (LC) and a mass spectrometer (MS) directly coupled by a transfer capillary. The eluent is directly introduced into the heated electron impact ion source of the MS. Significant advantages are the generation of reproducible spectra and the ability to ionize highly polar compounds. Boronic acids are used as coupling reagents to produce drugs, agrochemicals, or herbicides. The purity of educts is of high importance because impurities in the educt are directly associated with impurities in the product. Because of their high polarity and tendency to form boroxines, boronic acids require derivatization for GC analysis. The presented nano-LC-EI/MS method is easily applicable for a broad range of boronic acids. The method shows good detection limits for boronic acids up to 200 pg, is perfectly linear, and shows a very high robustness and reproducibility. A mixture of compounds could easily be separated on a monolithic RP18e column. The method represents a new, simple, robust, and reproducible approach for the detection of polar analytes. It is a good candidate to become a standard method for industrial applications.

  17. An electrospray ionization-ion mobility spectrometer as detector for high- performance liquid chromatography.

    Science.gov (United States)

    Zühlke, Martin; Riebe, Daniel; Beitz, Toralf; Löhmannsröben, Hans-Gerd; Zenichowski, Karl; Diener, Marc; Linscheid, Michael W

    2015-01-01

    The application of electrospray ionization (ESI) ion mobility (IM) spectrometry on the detection end of a high-performance liquid chromatograph has been a subject of study for some time. So far, this method has been limited to low flow rates or has required splitting of the liquid flow. This work presents a novel concept of an ESI source facilitating the stable operation of the spectrometer at flow rates between 10 μL mn(-1) and 1500 μL min(-1) without flow splitting, advancing the T-cylinder design developed by Kurnin and co-workers. Flow rates eight times faster than previously reported were achieved because of a more efficient dispersion of the liquid at increased electrospray voltages combined with nebulization by a sheath gas. Imaging revealed the spray operation to be in a rotationally symmetric multijet mode. The novel ESI-IM spectrometer tolerates high water contents (≤90%) and electrolyte concentrations up to 10mM, meeting another condition required of high-performance liquid chromatography (HPLC) detectors. Limits of detection of 50 nM for promazine in the positive mode and 1 μM for 1,3-dinitrobenzene in the negative mode were established. Three mixtures of reduced complexity (five surfactants, four neuroleptics, and two isomers) were separated in the millisecond regime in stand-alone operation of the spectrometer. Separations of two more complex mixtures (five neuroleptics and 13 pesticides) demonstrate the application of the spectrometer as an HPLC detector. The examples illustrate the advantages of the spectrometer over the established diode array detector, in terms of additional IM separation of substances not fully separated in the retention time domain as well as identification of substances based on their characteristic Ims.

  18. An allene-doped liquid argon ionization chamber for Ar and Ca ions at around 100 MeV/n

    CERN Document Server

    Yunoki, A; Fukuda, N; Kase, M; Kato, T; Kikuchi, J; Masuda, K; Niimura, M; Okada, H; Ozaki, K; Piao, Y; Shibamura, E; Tanaka, M; Tanihata, I; Terasawa, K

    1999-01-01

    An allene-doped liquid argon ionization chamber with 48 mmx48 mmx40 mm sensitive volume has been constructed for precise energy measurement of heavy ions at around 100 MeV/n. An energy resolution of 0.6%-0.7% (FWHM) was achieved for Ca and Ar ions both at 78 MeV/n. (author)

  19. CHARACTERIZATION OF DANSYLATED CYSTEINE, CYSTINE, GLUTATHIONE, AND GLUTATHIONE DISULFIDE BY NARROW BORE LIQUID CHROMATOGRAPHY - ELECTROSPRAY IONIZATION MASS SPECTROMETRY

    Science.gov (United States)

    A method using reversed phase high performance liquid chromtography/electrospray ionization-mass spectrometry (RP-LC/ESI-MS) has been developed to confirm the dientity of dansylated derivatives of cysteine (C) and glutathione (GSH), and their respective dimers, cystine (CSSC) and...

  20. CHARACTERIZATION OF DANSYLATED CYSTEINE, GLUTATHIONE DISULFIDE, CYSTEINE AND CYSTINE BY NARROW BORE LIQUID CHROMATOGRAPHY/ELECTROSPRAY IONIZATION MASS SPECTROMETRY

    Science.gov (United States)

    A method using reversed phase high performance liquid chromatography/electrospray ionization-mass spectrometric (RP-LC/ESI-MS) method has been developed to confirm the identity of dansylated derivatives of cysteine and glutathione, and their respective dimers. Cysteine, GSH, CSSC...

  1. Accurate quantitation of pentaerythritol tetranitrate and its degradation products using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry

    NARCIS (Netherlands)

    Brust, H.; Asten, A. van; Koeberg, M.; Dalmolen, J.; Heijden, A.E.D.M. van der; Schoenmakers, P.

    2014-01-01

    After an explosion of pentaerythritol tetranitrate (PETN), its degradation products pentaerythritol trinitrate (PETriN), dinitrate (PEDiN) and mononitrate (PEMN) were detected using liquid chromatography-atmospheric-pressure chemical-ionization-mass spectrometry (LC-APCI-MS). Discrimination between

  2. Cosmogenic activation of xenon and copper

    CERN Document Server

    Baudis, Laura; Piastra, Francesco; Schumann, Marc

    2015-01-01

    Rare event search experiments using liquid xenon as target and detection medium require ultra-low background levels to fully exploit their physics potential. Cosmic ray induced activation of the detector components and, even more importantly, of the xenon itself during production, transportation and storage at the Earth's surface, might result in the production of radioactive isotopes with long half-lives, with a possible impact on the expected background. We present the first dedicated study on the cosmogenic activation of xenon after 345 days of exposure to cosmic rays at the Jungfraujoch research station at 3470m above sea level, complemented by a study of copper which has been activated simultaneously. We have directly observed the production of 7Be, 101Rh, 125Sb, 126I and 127Xe in xenon, out of which only 125Sb could potentially lead to background for a multi-ton scale dark matter search. The production rates for five out of eight studied radioactive isotopes in copper are in agreement with the only exis...

  3. Requirements for Xenon International

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, James C.; Ely, James H.

    2013-09-26

    This document defines the requirements for the new Xenon International radioxenon system. The output of this project will be a Pacific Northwest National Laboratory (PNNL) developed prototype and a manufacturer-developed production prototype. The two prototypes are intended to be as close to matching as possible; this will be facilitated by overlapping development cycles and open communication between PNNL and the manufacturer.

  4. Requirements for Xenon International

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, James C.; Ely, James H.; Haas, Derek A.; Harper, Warren W.; Heimbigner, Tom R.; Hubbard, Charles W.; Humble, Paul H.; Madison, Jill C.; Morris, Scott J.; Panisko, Mark E.; Ripplinger, Mike D.; Stewart, Timothy L.

    2015-12-30

    This document defines the requirements for the new Xenon International radioxenon system. The output of this project will be a Pacific Northwest National Laboratory (PNNL) developed prototype and a manufacturer-developed production prototype. The two prototypes are intended to be as close to matching as possible; this will be facilitated by overlapping development cycles and open communication between PNNL and the manufacturer.

  5. Scalability, scintillation readout and charge drift in a kilogram scale solid xenon particle detector

    CERN Document Server

    Yoo, J; Jaskierny, W F; Markley, D; Pahlka, R B; Balakishiyeva, D; Saab, T; Filipenko, M

    2014-01-01

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that in liquid phase. We used a conventional time projection chamber system to measure the electron drift time in a kilogram of solid xenon and observed faster electron drift speed in the solid phase xenon compared to that in the liquid phase.

  6. Scalability, Scintillation Readout and Charge Drift in a Kilogram Scale Solid Xenon Particle Detector

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J. [Fermilab; Cease, H. [Fermilab; Jaskierny, W. F. [Fermilab; Markley, D. [Fermilab; Pahlka, R. B. [Fermilab; Balakishiyeva, D. [Florida U.; Saab, T. [Florida U.; Filipenko, M. [Erlangen - Nuremberg U., ECAP

    2014-10-23

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employ a liquid nitrogen cooled cryostat combined with a xenon purification and chiller system to measure the scintillation light output and electron drift speed from both the solid and liquid phases of xenon. Scintillation light output from sealed radioactive sources is measured by a set of high quantum efficiency photomultiplier tubes suitable for cryogenic applications. We observed a reduced amount of photons in solid phase compared to that in liquid phase. We used a conventional time projection chamber system to measure the electron drift time in a kilogram of solid xenon and observed faster electron drift speed in the solid phase xenon compared to that in the liquid phase.

  7. Measuring radon reduction in xenon boil-off gas

    Energy Technology Data Exchange (ETDEWEB)

    Bruenner, Stefan; Cichon, Dominick; Lindemann, Sebastian; Marrodan Undagoitia, Teresa; Simgen, Hardy [MPIK, Heidelberg (Germany)

    2016-07-01

    {sup 222}Rn, which originates from the decay of primordial {sup 238}U, is one of the major background sources for ultra-low background noble gas detectors. One of them is XENON1T, which is a dark matter direct detection experiment looking for hypothetical weakly interacting massive particles (WIMPs). It uses liquid xenon (LXe) as a detection medium and aims to be sensitive to spin-independent WIMP-nucleon cross-sections of σ∝2.10{sup -47} cm{sup 2} at a WIMP mass of ∝50 GeV/c{sup 2}. To achieve this goal, radon activity inside the detector must be limited to a few mBq/kg. One possible way for reducing the concentration of {sup 222}Rn inside such an LXe detector is using the so-called ''boil-off method''. It takes advantage of the fact, that the radon concentration in boil-off xenon is smaller compared to the concentration in the liquid xenon from which the boil-off xenon evaporated. This can be understood by the different vapor pressures of radon and xenon. In this talk, tests conducted at the MPIK are outlined which probe the feasibility and effectiveness of the boil-off method. The results prove, that a reduction of the radon concentration can indeed be achieved. In addition, an outlook for possible future applications of this technique is given.

  8. Capillary liquid chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

    Science.gov (United States)

    Ostman, Pekka; Jäntti, Sirkku; Grigoras, Kestas; Saarela, Ville; Ketola, Raimo A; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

    2006-07-01

    A miniaturized nebulizer chip for capillary liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (capillary LC-microchip APCI-MS) is presented. The APCI chip consists of two wafers, a silicon wafer and a Pyrex glass wafer. The silicon wafer has a DRIE etched through-wafer nebulizer gas inlet, an edge capillary insertion channel, a stopper, a vaporizer channel and a nozzle. The platinum heater electrode and pads for electrical connection were patterned on to the Pyrex glass wafer. The two wafers were joined by anodic bonding, creating a microchip version of an APCI-source. The sample inlet capillary from an LC column is directly connected to the vaporizer channel of the APCI chip. The etched nozzle in the microchip forms a narrow sample plume, which is ionized by an external corona needle, and the formed ions are analyzed by a mass spectrometer. The nebulizer chip enables for the first time the use of low flow rate separation techniques with APCI-MS. The performance of capillary LC-microchip APCI-MS was tested with selected neurosteroids. The capillary LC-microchip APCI-MS provides quantitative repeatability and good linearity. The limits of detection (LOD) with a signal-to-noise ratio (S/N) of 3 in MS/MS mode for the selected neurosteroids were 20-1000 fmol (10-500 nmol l(-1)). LODs (S/N = 3) with commercial macro APCI with the same compounds using the same MS were about 10 times higher. Fast heat transfer allows the use of the optimized temperature for each compound during an LC run. The microchip APCI-source provides a convenient and easy method to combine capillary LC to any API-MS equipped with an APCI source. The advantages and potentials of the microchip APCI also make it a very attractive interface in microfluidic APCI-MS.

  9. 暗物质探测器的液氙低温精馏系统研制%Design and Construction of a Cryogenic Distillation System of Liquid Xenon for Dark Matter Detector

    Institute of Scientific and Technical Information of China (English)

    王舟; 张华; 巨永林

    2013-01-01

    To reduce the radio krypton-85 concentration in liquid xenon,which is one of the commendable detecting media for dark matter detection,an efficient cryogenic distillation system to remove the krypton from the commercially available xenon was specifically designed,developed and constructed by using the McCabe-Thiele (M-T) method,mass conservation and energy conservation.The core of the distillation system is the packing tower which is 4 m high and 80 mm in diameter where a kind of efficient new structured packing PACK-13C was used.This distillation system can reduce the krypton in the xenon from 10-9to 10-12 with 99% of Xe collection efficiency (i.e.,the amount of Xe rejected is only 1%) at a maximum flow rate of 5 kg/h (15SLPM),which is crucial for the dark matter detector with a high-sensitivity and low-background.%针对暗物质探测器中降低介质液氙中放射性氪-85含量可获得高纯度氙的问题,通过Mc-Cabe-Thiele(M-T)法及质量、能量守恒,设计并研制出一种将氪从氙中提取出且可获得高纯度氙气的高效低温精馏系统.该精馏系统中的主要结构精馏塔采用填料塔形式,填料为高效新型规整填料PACK-13C,塔高4m,直径80 mm,其中精馏段1.9m,提馏段2.1m.该精馏系统可以在回收率为99%的情况下,以5 kg/h(15SLPM)的速率将氙中氪的含量从10-9降低到10-12,这对要求高精度、高灵敏度、低本底的大型暗物质探测器的研制至关重要.

  10. Improvement of sugar analysis sensitivity using anion-exchange chromatography-electrospray ionization mass spectrometry with sheath liquid interface.

    Science.gov (United States)

    Xu, Xian-Bing; Liu, Ding-Bo; Guo, Xiao Ming; Yu, Shu-Juan; Yu, Pei

    2014-10-31

    A novel interface that enables high-performance anion-exchange chromatography (HPAEC) to be coupled with electrospray ionization (ESI) mass spectrometry (MS) is reported. A sheath liquid consisting of 50mM NH4Ac in isopropanol with 0.05% acetic acid, infused at a flow rate of 3μL/min at the tip of the electrospray probe, requires less ESI source cleaning and promotes efficient ionization of mono- and di-carbohydrates. The results suggest that use of a sheath liquid interface rather than a T-joint allows volatile ammonium salts to replace non-volatile metal salts as modifiers for improving sugar ESI signals. The efficient ionization of mono- and di-carbohydrates in the ESI source is affected by the sheath liquid properties such as buffer concentration and type of organic solvent. HPAEC-ESI-MS was used for the analysis of monocarbohydrates in pectins, particularly co-eluted sugars, and the performance was evaluated. Addition of a make-up solution through the sheath liquid interface proved to be an efficient tool for enhancing the intensities of sugars analyzed using HPAEC-ESI-MS.

  11. Determination of tetramine in marine gastropods by liquid chromatography/electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Kawashima, Yoko; Nagashima, Yuji; Shiomi, Kazuo

    2004-08-01

    Tetramine (tetramethylammonium ion) is found at high levels (several mg/g) in the salivary gland of buccinid gastropods and has been involved in numerous poisoning incidents after ingestion of those gastropods. A sensitive and selective determination method for tetramine, which is based on a combination of liquid chromatography (LC) and electrospray ionization-single quadrupole mass spectrometry (ESI-MS), was developed. Following separation by LC on a cation-exchange column, tetramine was easily detected by simultaneous monitoring of a molecular ion (m/z 74) at a cone voltage of 30 V and a fragment ion (m/z 58) at 70 V. A linear calibration curve was obtained in the range of 0.1-100 ng by plotting the peak areas of the molecular ion versus the amounts of tetramine. Spiking experiments demonstrated that tetramine in gastropod tissues can be determined by the LC/ESI-MS method, without being affected by sample matrices as well as the extration procedure. Applications of the new method to gastropod samples revealed that a small amount of tetramine is contained even in mid-gut gland and muscle and that tetramine in the salivary gland diffuses to other tissues during boiling and slow thawing.

  12. Analysis of antibiotics from liquid sample using electrospray ionization-ion mobility spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li Shu; Jia Jian; Gao Xiaoguang; He Xiuli [State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China); Li Jianping, E-mail: jpli@mail.ie.ac.cn [State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer The reduced mobilities of 18 antibiotics are determined. Black-Right-Pointing-Pointer Establishing antibiotic mass-mobility correlation using (12,4) potential model. Black-Right-Pointing-Pointer Multi-component characteristics of antibiotics can be revealed using ESI-IMS. Black-Right-Pointing-Pointer Most mixtures of antibiotics can be analyzed using ESI-IMS. Black-Right-Pointing-Pointer The detection limit of amoxicillin is 70 pg. - Abstract: The recent findings of antibiotic residues in aquatic environment at trace level have gained much concern for the detrimental effect on ecological and human health due to bacterial resistance. Here, the feasibility of using electrospray ionization ion mobility spectrometry (ESI-IMS) for analysis antibiotics in liquid sample is demonstrated. Reduced mobilities and collision cross sections of 18 antibiotics are experimentally measured and compared with theoretical values according to mass-mobility correlation. Gentamicin is used as an example to investigate the capability of ESI-IMS for multi-component analysis of antibiotics. Mixtures of antibiotics at different concentrations are analyzed. The estimated detection limit for amoxicillin is 0.7 mg L{sup -1} (70 pg) and the linear range of response maintains over two orders. This method will be a potential technique for the analysis of antibiotics in aquatic environment.

  13. Liquid ionization chamber initial recombination dependence on LET for electrons and photons.

    Science.gov (United States)

    Johansson, Erik; Andersson, Jonas; Johansson, Lennart; Tölli, Heikki

    2013-06-21

    The possibility of indirect measurements of linear energy transfer (LET) with a liquid ionization chamber (LIC) has been investigated by studying initial recombination losses at different applied voltages. A linear fit is made to the voltage-signal curve and the intersection point of the fit and the voltage-axis is shown to correlate with LET. The LIC applied voltages were 100-700 V, which corresponds to electric field strengths between 0.3 and 2.0 MV m(-1). Several different photon and electron beams have been studied, and by using MCNPX™ the respective LET spectra have been determined. The beam qualities in this study were found to have a fluence averaged LET between 0.17 and 1.67 keV µm(-1) and a corresponding dose averaged LET between 0.97 and 4.62 keV µm(-1). For the experimental data in this study the linear fit method yields consistent results with respect to Monte Carlo simulated LET values. A calibration curve for LET determination is provided for the LIC used in the present work.

  14. Detecting MLC errors in stereotactic radiotherapy plans with a liquid filled ionization chamber array.

    Science.gov (United States)

    O'Connor, Patrick; Seshadri, Venkatakrisnan; Charles, Paul

    2016-03-01

    Quality assurance of stereotactic radiotherapy demands the use of equipment with the highest resolution and sensitivity available. This study examines the sensitivity of a commercially available liquid-filled ionization chamber array--the Octavius 1000 SRS (PTW, Frieburg, Germany) for detecting small (sub-millimetre) multi-leaf collimator (MLC) alignment errors in static square fields (side length 16-40 mm). Furthermore, the effectiveness of detecting small MLC errors in clinical stereotactic radiotherapy patient plans using the device was also evaluated. The commonly used gamma pass rate metric (of the measurements compared with treatment planning system generated results) was used. The gamma pass rates were then evaluated as a function of MLC position error (MLC error size 0.1-2.5 mm). The detector array exhibited a drop in pass rate between plans without error and those which had MLC errors induced. For example a drop in pass rate of 4.5% (gamma criteria 3%, 1 mm) was observed when a 0.8 mm error was introduced into a 16 mm square field. Furthermore the drop in pass rate increased as the MLC position error increased. This study showed that the Octavius 1000 SRS array could be a useful tool for applications requiring the detection of small geometric delivery uncertainties.

  15. Crosslinking of polysaccharides in room temperature ionic liquids by ionizing radiation

    Science.gov (United States)

    Kimura, Atsushi; Nagasawa, Naotsugu; Shimada, Akihiko; Taguchi, Mitsumasa

    2016-07-01

    Crosslinking of polysaccharides in room temperature ionic liquids (RTILs) by ionizing radiation were investigated by the scavenging method, fluorescent and X-ray photoelectron spectroscopy (XPS) analysis. Radiation chemical yields of hydroxyl radicals inducing the crosslinking of cellulose were estimated with phenol as a scavenger, and increased with water content in 1-ethyl-3-methylimidazolium acetate (EMI-acetate). Cellulose gel was also produced in fluorescent carboxylate-based RTILs, 1,3-dibutylimidazolium acetate (DBI-acetate). Light emission from DBI-acetate in cellulose gel was observed and 20-nm red shifted at a maximum wavelength of 415 nm when excited at 323 nm. Expected elements of carbon and oxygen were detected in neat cellulose by XPS, while additional nitrogen was detected in radiation-crosslinked cellulose gel produced in EMI-acetate. These results indicate that RTILs is incorporated in the cellulose gel. Chitin gel was first obtained in 1-butyl-3-methyimidazolium chloride by γ-ray irradiations, and its gel fraction increased with the dose and reached 86% at 60 kGy.

  16. First demonstration of a sub-keV electron recoil energy threshold in a liquid argon ionization chamber

    CERN Document Server

    Sangiorgio, S; Coleman, J; Foxe, M; Hagmann, C; Joshi, T H; Jovanovic, I; Kazkaz, K; Mavrokoridis, K; Mozin, V; Pereverzev, S; Sorensen, P

    2013-01-01

    We make a first demonstration of a sub-keV electron recoil energy threshold in a dual-phase liquid argon time-projection chamber. This is an important step in a program to build a detector capable of identifying the ionization signal resulting from nuclear recoils at a few keV and below. We obtained this result by observing the peaks in the energy spectrum at 2.82 keV and 0.27 keV, following the K- and L-shell electron capture decay of Ar-37. We describe the details of the Ar-37 source preparation, as this calibration technique may prove useful, e.g. for dark matter direct detection experiments. A Fe-55 internal x-ray source was also measured simultaneously and provided another calibration point at 5.9 keV. We discuss the ionization yield and electron recombination in liquid argon at the three calibration energies.

  17. Determination of Macrolide Antibiotics Using Dispersive Liquid-Liquid Microextraction Followed by Surface-Assisted Laser Desorption/Ionization Mass Spectrometry

    Science.gov (United States)

    Chen, Kuan-Yu; Yang, Thomas C.; Chang, Sarah Y.

    2012-06-01

    A novel method for the determination of macrolide antibiotics using dispersive liquid-liquid microextraction coupled to surface-assisted laser desorption/ionization mass spectrometric detection was developed. Acetone and dichloromethane were used as the disperser solvent and extraction solvent, respectively. A mixture of extraction solvent and disperser solvent were rapidly injected into a 1.0 mL aqueous sample to form a cloudy solution. After the extraction, macrolide antibiotics were detected using surface-assisted laser desorption/ionization mass spectrometry (SALDI/MS) with colloidal silver as the matrix. Under optimum conditions, the limits of detection (LODs) at a signal-to-noise ratio of 3 were 2, 3, 3, and 2 nM for erythromycin (ERY), spiramycin (SPI), tilmicosin (TILM), and tylosin (TYL), respectively. This developed method was successfully applied to the determination of macrolide antibiotics in human urine samples.

  18. Quantitative determination of acetylcholine in microdialysis samples using liquid chromatography/atmospheric pressure spray ionization mass spectrometry.

    Science.gov (United States)

    Keski-Rahkonen, Pekka; Lehtonen, Marko; Ihalainen, Jouni; Sarajärvi, Timo; Auriola, Seppo

    2007-01-01

    A fast, simple and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of acetylcholine in rat brain microdialysis samples. The chromatographic separation was achieved in 3 min on a reversed-phase column with isocratic conditions using a mobile phase containing 2% (v/v) of acetonitrile and 0.05% (v/v) of trifluoroacetic acid (TFA). A stable isotope-labeled internal standard was included in the analysis and detection was carried out with a linear ion trap mass spectrometer using selected reaction monitoring (SRM). Analyte ionization was performed with an atmospheric pressure chemical ionization (APCI) source without applying discharge current (atmospheric pressure spray ionization). This special ionization technique offered significant advantages over electrospray ionization for the analysis of acetylcholine with reversed-phase ion-pairing chromatography. The lower limit of quantification was 0.15 nM (1.5 fmol on-column) and linearity was maintained over the range of 0.15-73 nM, providing a concentration range that is significantly wider than that of the existing LC/MS methods. Good accuracy and precision were obtained for concentrations within the standard curve range. The method was validated and has been used extensively for the determination of acetylcholine in rat brain microdialysis samples.

  19. General collection efficiency for liquid isooctane and tetramethylsilane used as sensitive media in a parallel-plate ionization chamber.

    Science.gov (United States)

    Johansson, B; Wickman, G

    1997-01-01

    The general collection efficiency has been measured in liquid isooctane (C8H18) and tetramethylsilane (Si(CH3)4) used as the sensitive media in a parallel-plate ionization chamber, with an electrode distance of 1 mm, intended for photon and electron dosimetry applications. The liquid ionization chamber was irradiated at different dose rates by 140 keV photons from the decay of radioactive 99mTc. The measurements were made at potential differences of 50, 100, 200 and 500 V. Measurements were performed for each liquid and electric field strength, with the decay rate of 99mTc used as the dose-rate reference. The maximum dose rate was about 150 mGy min-1 in each experiment. When the measured general collection efficiency values are compared with the theoretical predictions for collection efficiency in gases, it is found that the latter also describe the general collection efficiency in the two liquids within 1% of the saturation current for collection efficiencies down to 60% when using experimentally determined recombination rate constants and on mobilities characteristic of each of the liquids.

  20. NMR investigations of surfaces and interfaces using spin-polarized xenon

    Energy Technology Data Exchange (ETDEWEB)

    Gaede, Holly Caroline [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1995-07-01

    129Xe NMR is potentially useful for the investigation of material surfaces, but has been limited to high surface area samples in which sufficient xenon can be loaded to achieve acceptable signal to noise ratios. In Chapter 2 conventional 129Xe NMR is used to study a high surface area polymer, a catalyst, and a confined liquid crystal to determine the topology of these systems. Further information about the spatial proximity of different sites of the catalyst and liquid crystal systems is determined through two dimensional exchange NMR in Chapter 3. Lower surface area systems may be investigated with spin-polarized xenon, which may be achieved through optical pumping and spin exchange. Optically polarized xenon can be up to 105times more sensitive than thermally polarized xenon. In Chapter 4 highly polarized xenon is used to examine the surface of poly(acrylonitrile) and the formation of xenon clathrate hydrates. An attractive use of polarized xenon is as a magnetization source in cross polarization experiments. Cross polarization from adsorbed polarized xenon may allow detection of surface nuclei with drastic enhancements. A non-selective low field thermal mixing technique is used to enhance the 13C signal of CO2 of xenon occluded in solid CO2 by a factor of 200. High-field cross polarization from xenon to proton on the surface of high surface area polymers has enabled signal enhancements of ~1,000. These studies, together with investigations of the efficiency of the cross polarization process from polarized xenon, are discussed in Chapter 5. Another use of polarized xenon is as an imaging contrast agent in systems that are not compatible with traditional contrast agents. The resolution attainable with this method is determined through images of structured phantoms in Chapter 6.

  1. First demonstration of a sub-keV electron recoil energy threshold in a liquid argon ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Sangiorgio, S., E-mail: samuele@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Joshi, T.H. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Department of Nuclear Engineering, University of California, Berkeley, CA 94720 (United States); Bernstein, A. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Coleman, J. [Department of Physics, University of Liverpool, Oxford St, Liverpool L69 7Ze (United Kingdom); Foxe, M. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Hagmann, C. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Jovanovic, I. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Kazkaz, K. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Mavrokoridis, K. [Department of Physics, University of Liverpool, Oxford St, Liverpool L69 7Ze (United Kingdom); Mozin, V.; Pereverzev, S.; Sorensen, P. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States)

    2013-11-11

    We describe the first demonstration of a sub-keV electron recoil energy threshold in a dual-phase liquid argon time projection chamber. This is an important step in an effort to develop a detector capable of identifying the ionization signal resulting from nuclear recoils with energies of order a few keV and below. We obtained this result by observing the peaks in the energy spectrum at 2.82 keV and 0.27 keV, following the K- and L-shell electron capture decay of {sup 37}Ar respectively. The {sup 37}Ar source preparation is described in detail, since it enables calibration that may also prove useful in dark matter direct detection experiments. An internally placed {sup 55}Fe x-ray source simultaneously provided another calibration point at 5.9 keV. We discuss the ionization yield and electron recombination in liquid argon at those three calibration energies. -- Highlights: • We measure sub-keV electron recoils in a dual-phase argon time projection chamber. • Ar-37 is produced via neutron irradiation and used as calibration source. • Ar-37 electron captures at 2.82 and 0.27 keV are measured together with Fe-55 x-rays. • Spurious single ionization electrons provided absolute calibration of charge signal. • Modified Thomas–Imel model describes low-energy electron-recoils in liquid Ar.

  2. Analysis of 30 synthetic cannabinoids in serum by liquid chromatography-electrospray ionization tandem mass spectrometry after liquid-liquid extraction.

    Science.gov (United States)

    Kneisel, Stefan; Auwärter, Volker

    2012-07-01

    The analysis of synthetic cannabinoids in human matrices is of particular importance in the fields of forensic and clinical toxicology since cannabis users partly shift to the consumption of 'herbal mixtures' as a legal alternative to cannabis products in order to circumvent drug testing. However, comprehensive methods covering the majority of synthetic cannabinoids already identified on the drug market are still lacking. In this article, we present a fully validated method for the analysis of 30 synthetic cannabinoids in human serum utilizing liquid-liquid extraction and liquid chromatography-electrospray ionization tandem mass spectrometry. The method proved to be suitable for the quantification of 27 substances. The limits of detection ranged from 0.01 to 2.0 ng/mL, whereas the lower limits of quantification were in the range from 0.1 to 2.0 ng/mL. The presented method was successfully applied to 833 authentic serum samples during routine analysis between August 2011 and January 2012. A total of 227 (27%) samples was tested positive for at least one of the following synthetic cannabinoids: JWH-018, JWH-019, JWH-073, JWH-081, JWH-122, JWH-200, JWH-203, JWH-210, JWH-307, AM-2201 and RCS-4. The most prevalent compounds in positive samples were JWH-210 (80%), JWH-122 (63%) as well as AM-2201 (29%). Median serum concentrations were all below 1.0 ng/mL. These findings demonstrate a significant shift of the market of synthetic cannabinoids towards substances featuring a higher CB(1) binding affinity and clearly emphasize that the analysis of synthetic cannabinoids in serum or blood samples requires highly sensitive analytical methods covering a wide spectrum of substances. Copyright © 2012 John Wiley & Sons, Ltd.

  3. Removal of noble gases out of xenon by a cryogenic distillation column for the XENON1T experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fieguth, Alexander; Murra, Michael; Rosendahl, Stephan; Bruno, Gianmarco; Schneider, Sergej; Weinheimer, Christian; Huhmann, Christian [Institut fuer Kernphysik, WWU Muenster (Germany)

    2015-07-01

    The upcoming XENON1T experiment is the next step for the dark matter particle search. It will surpass current limits on the WIMP-nucleon cross section set by liquid xenon detectors as LUX and XENON100 by more than an order of magnitude, which leads to an expected sensitivity of 2.0.10{sup -47} cm{sup 2} for WIMPs with a mass of 50 GeV/c{sup 2} after a 2.2 ton-year live-time. For achieving new sensitivity limits the reduction of internal background sources as {sup 85}Kr and {sup 222}Rn is of crucial importance. Taking advantage of the different boiling points of these noble gas impurities and xenon, they can be separated by a cryogenic distillation column in different steps. The improvement of the krypton removal by distillation for the XENON1T experiment and a first test setup on radon distillation at the XENON100 experiment are presented.

  4. Removal of noble gases out of xenon by a cryogenic distillation column for the XENON1T experiment

    Energy Technology Data Exchange (ETDEWEB)

    Murra, Michael; Bruno, Gianmarco; Fieguth, Alexander; Huhmann, Christian; Rosendahl, Stephan; Schneider, Sergej; Weinheimer, Christian [Institut fuer Kernphysik, Westfaelische-Wilhelms Universitaet Muenster (Germany)

    2015-07-01

    The XENON1T experiment is the next generation experiment for the direct detection of dark matter in the form of Weakly Interacting Massive Particles (WIMPS). With its 3.3 tons of liquid xenon XENON1T will increase the sensitivity on the WIMP-nucleon cross section down to 2.0 x 10{sup -47} cm{sup 2}, which is more than one order of magnitude better than the current best limits by LUX and XENON100. A key requirement to reach this sensitivity is the reduction of radioactive backgrounds such as {sup 85}Kr and {sup 222}Rn. Because of different boiling points of Kr and Xe both components can be separated by a cryogenic distillation column, which has been constructed and characterized for XENON1T, where a reduction factor greater 120000 has been confirmed. Based on the same principle, the separation of Rn and Xe by cryogenic distillation is currently being tested at XENON100, using the system as radon source and detector at the same time. The cryogenic distillation column, the krypton removal measurements as well as the radon removal tests are presented.

  5. Observation of different ceramide species from crude cellular extracts by normal-phase high-performance liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry

    NARCIS (Netherlands)

    Pettus, BJ; Bielawska, A; Kroesen, BJ; Moeller, PDR; Szulc, ZM; Hannun, YA; Busman, M

    2003-01-01

    Normal-phase high-performance liquid chromatography (NP-HPLC) coupled to atmospheric pressure chemical ionization mass spectrometry (APCI-MS) allows qualitative analysis of endogenous ceramide and dihydroceramide species from crude lipid extracts utilizing chromatographic methods readily adaptable

  6. Matrix influence on derivatization and ionization processes during selenoamino acid liquid chromatography electrospray ionization mass spectrometric analysis.

    Science.gov (United States)

    Rebane, Riin; Oldekop, Maarja-Liisa; Herodes, Koit

    2014-04-01

    Considering the importance of derivatization in LC/ESI/MS analysis, the objective of this work was to develop a method for evaluation of matrix effect that would discriminate between matrix effect due to the derivatization reaction yield and from the ESI. Four derivatization reagents (TAHS, DEEMM, DNS, FMOC-Cl) were studied with respect to matrix effects using two selenoamino acids and onion matrix as model system. A novel method for assessing matrix effects of LC/ESI/MS analyses involving derivatization is proposed, named herein post-derivatization spiking, that allows evaluating effect of matrix on ESI ionization without derivatization reaction yield contribution. The proposed post-derivatization spiking method allowed to demonstrate that the reason of reduced analytical signal can be signal suppression in ESI (as in case of DNS derivatives with matrix effects 38-99%), alteration of derivatization reaction yield (TAHS, matrix effects 92-113%, but reaction yields 20-50%) or both (FMOC-Cl, matrix effects 28-88% and reaction yields 50-70%). In case of DEEMM derivatives, matrix reduces reaction yield but enhances ESI/MS signal. A method for matrix effect evaluation was developed. It was also confirmed that matrix effects can be reduced by dilution.

  7. Liquid chromatographic study of the enzymatic degradation of endomorphins, with identification by electrospray ionization mass spectrometry.

    Science.gov (United States)

    Péter, A; Tóth, G; Tömböly, C; Laus, G; Tourwè, D

    1999-06-18

    The recently discovered native endomorphins play an important role in opioid analgesia, but their metabolic fate in the organism remains relatively little known. This paper describes the application of high-performance liquid chromatography combined with electrospray ionization mass spectrometry to identify the degradation products resulting from the incubation of endomorphins with proteolytic enzymes. The native endomorphin-1, H-Tyr-Pro-Trp-Phe-NH2 (1), and endomorphin-2, H-Tyr-Pro-Phe-Phe-NH2 (2), and an analog of endomorphin-2, H-Tyr-Pro-Phe-Phe-OH (3), were synthetized, and the levels of their resistance against carboxypeptidase A, carboxypeptidase Y, aminopeptidase M and proteinase A were determined. The patterns of peptide metabolites identified by this method indicated that carboxypeptidase Y first hydrolyzes the C-terminal amide group to a carboxy group, and then splits the peptides at the Trp3-Phe4 or Phe3-Phe4 bond. The remaining fragment peptides are stable against the enzymes investigated. Carboxypeptidase A degrades only analog 3 at the Phe3-Phe4 bond. Aminopeptidase M cleaves the peptides at the Pro2-Trp3 or Pro2-Phe3 bond. The C-terminal fragments hydrolyze further, giving amino acids and Phe-NH2-s while the N-terminal part displays a resistance to further aminopeptidase M digestion. Proteinase A exhibits a similar effect to carboxypeptidase Y: the C-terminal amide group is first converted to a carboxy group, and one amino acid is then split off from the C-terminal side.

  8. The stability of liquid-filled matrix ionization chamber electronic portal imaging devices for dosimetry purposes.

    Science.gov (United States)

    Louwe, R J W; Tielenburg, R; van Ingen, K M; Mijnheer, B J; van Herk, M B

    2004-04-01

    This study was performed to determine the stability of liquid-filled matrix ionization chamber (LiFi-type) electronic portal imaging devices (EPID) for dosimetric purposes. The short- and long-term stability of the response was investigated, as well as the importance of factors influencing the response (e.g., temperature fluctuations, radiation damage, and the performance of the electronic hardware). It was shown that testing the performance of the electronic hardware as well as the short-term stability of the imagers may reveal the cause of a poor long-term stability of the imager response. In addition, the short-term stability was measured to verify the validity of the fitted dose-response curve immediately after beam startup. The long-term stability of these imagers could be considerably improved by correcting for room temperature fluctuations and gradual changes in response due to radiation damage. As a result, the reproducibility was better than 1% (1 SD) over a period of two years. The results of this study were used to formulate recommendations for a quality control program for portal dosimetry. The effect of such a program was assessed by comparing the results of portal dosimetry and in vivo dosimetry using diodes during the treatment of 31 prostate patients. The improvement of the results for portal dosimetry was consistent with the deviations observed with the reproducibility tests in that particular period. After a correction for the variation in response of the imager, the average difference between the measured and prescribed dose during the treatment of prostate patients was -0.7%+/-1.5% (1 SD), and -0.6%+/-1.1% (1 SD) for EPID and diode in vivo dosimetry, respectively. It can be concluded that a high stability of the response can be achieved for this type of EPID by applying a rigorous quality control program.

  9. Optical pumping and xenon NMR

    Energy Technology Data Exchange (ETDEWEB)

    Raftery, M. Daniel [Univ. of California, Berkeley, CA (United States)

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.

  10. Optical pumping and xenon NMR

    Energy Technology Data Exchange (ETDEWEB)

    Raftery, M.D.

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping [sup 129]Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the [sup 131]Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.

  11. A two-dose-rate method for general recombination correction for liquid ionization chambers in pulsed beams

    Energy Technology Data Exchange (ETDEWEB)

    Toelli, Heikki; Sjoegren, Rickard; Wendelsten, Mikael, E-mail: heikki.tolli@radfys.umu.s [Department of Radiation Sciences, Radiation Physics, Umeaa University, SE-901 85 Umeaa (Sweden)

    2010-08-07

    The correction for general recombination losses in liquid ionization chambers (LICs) is more complex than that in air-filled ionization chambers. The reason for this is that the saturation charge in LICs, i.e. the charge that escapes initial recombination, depends on the applied voltage. This paper presents a method, based on measurements at two different dose rates in a pulsed beam, for general recombination correction in LICs. The Boag theory for pulsed beams is used and the collection efficiency is determined by numerical methods which are equivalent to the two-voltage method used in dosimetry with air-filled ionization chambers. The method has been tested in experiments in water in a 20 MeV electron beam using two LICs filled with isooctane and tetramethylsilane. The dose per pulse in the electron beam was varied between 0.1 mGy/pulse and 8 mGy/pulse. The relative standard deviations of the collection efficiencies determined with the two-dose-rate method ranged between 0.1% and 1.5%. The dose-rate variations of the general recombination corrected charge measured with the LICs are in excellent agreement with the corresponding values obtained with an air-filled plane parallel ionization chamber.

  12. High Pressure XENON Gamma-Ray Spectrometers for Field Use

    Energy Technology Data Exchange (ETDEWEB)

    David K. Wehe; Zong He; Glenn K. Knoll

    2004-02-16

    This project explored a new concept for high-pressure xenon ionization chambers by replacing the Frisch grid with coplanar grid electrodes similar to those used in wide bandgap semiconductor gamma-ray spectrometers. This work is the first attempt to apply the coplanar grid anode design in a gas ionization chamber in order to achieve to improved energy resolution. Three prototype detectors, two cylindrical and one parallel plate configurations, were built and tested. While the detectors did not demonstrate energy resolutions as good as other high pressure xenon gamma-ray spectrometers, the results demonstrated that the concept of single polarity charge sending using coplanar grid electrodes will work in a gas detector.

  13. Driving Rabi oscillations at the giant dipole resonance in xenon

    CERN Document Server

    Pabst, Stefan; Santra, Robin

    2015-01-01

    Free-electron lasers (FELs) produce short and very intense light pulses in the XUV and x-ray regimes. We investigate the possibility to drive Rabi oscillations in xenon with an intense FEL pulse by using the unusually large dipole strength of the giant-dipole resonance (GDR). The GDR decays within less than 30 as due to its position, which is above the $4d$ ionization threshold. We find that intensities around 10$^{18}$ W/cm$^2$ are required to induce Rabi oscillations with a period comparable to the lifetime. The pulse duration should not exceed 100 as because xenon will be fully ionized within a few lifetimes. Rabi oscillations reveal themselves also in the photoelectron spectrum in form of Autler-Townes splittings extending over several tens of electronvolt.

  14. 大容量零损耗液氙储罐系统的设计与研制%Design and development of a large volume zero boil-off liquid xenon storage system

    Institute of Scientific and Technical Information of China (English)

    鲍磊; 郝熙欢; 巨永林

    2012-01-01

    对于基于液氙的暗物质探测,在探测开启之前、暂停或者出现故障时需要回收储存2.5吨左右的液氙,为此研制了一套大容量零损耗的液氙储罐系统.文中介绍了该储罐系统的结构组成,计算了液氙杜瓦的漏热损失,并在此漏热分析的基础上选定了一款脉冲管制冷机提供冷量,以实现液氙的零损耗稳定储存.%For the dark matter detector with liquid xenon(LXe) , about 2. 5 tons of LXe need to be recovered and stored before the start of experiment, or during the detector maintenance in the period of shutdown, etc. To meet the requirements, a cryogenic LXe storage system was built. The structure of the system was introduced and the heat losses were calculated in the paper. One type of pulse tube refrigerator was selected on base of the heat losses to ensure that the LXe was stored with zero boil - off.

  15. GraXe, graphene and xenon for neutrinoless double beta decay searches

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Monrabal, F.; Vidal, J. Muñoz [Instituto de Física Corpuscular (IFIC), CSIC and Universitat de Valencia, Calle Catedrático José Beltrán, 2, 46980 Valencia (Spain); Guinea, F. [Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, Calle Sor Juana Inés de la Cruz, 3, 28049 Madrid (Spain); Fogler, M.M. [Department of Physics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093 (United States); Katsnelson, M.I., E-mail: gomez@mail.cern.ch, E-mail: paco.guinea@icmm.csic.es, E-mail: mfogler@ucsd.edu, E-mail: katsnel@sci.kun.nl, E-mail: justo.martin-albo@ific.uv.es, E-mail: francesc.monrabal@ific.uv.es, E-mail: jmunoz@ific.uv.es [Institute for Molecules and Materials, Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

    2012-02-01

    We propose a new detector concept, GraXe (to be pronounced as grace), to search for neutrinoless double beta decay in {sup 136}XE. GraXe combines a popular detection medium in rare-event searches, liquid xenon, with a new, background-free material, graphene. In our baseline design of GraXe, a sphere made of graphene-coated titanium mesh and filled with liquid xenon (LXe) enriched in the {sup 136}XE isotope is immersed in a large volume of natural LXe instrumented with photodetectors. Liquid xenon is an excellent scintillator, reasonably transparent to its own light. Graphene is transparent over a large frequency range, and impermeable to the xenon. Event position could be deduced from the light pattern detected in the photosensors. External backgrounds would be shielded by the buffer of natural LXe, leaving the ultra-radiopure internal volume virtually free of background. Industrial graphene can be manufactured at a competitive cost to produce the sphere. Enriching xenon in the isotope {sup 136}XE is easy and relatively cheap, and there is already near one ton of enriched xenon available in the world (currently being used by the EXO, KamLAND-Zen and NEXT experiments). All the cryogenic know-how is readily available from the numerous experiments using liquid xenon. An experiment using the GraXe concept appears realistic and affordable in a short time scale, and its physics potential is enormous.

  16. GraXe, graphene and xenon for neutrinoless double beta decay searches

    CERN Document Server

    Gomez-Cadenas, J J; Fogler, M M; Katsnelson, M I; Martin-Albo, J; Monrabal, F; Muñoz-Vidal, J

    2011-01-01

    We propose a new detector concept, GraXe (to be pronounced as grace), to search for neutrinoless double beta decay in Xe-136. GraXe combines a popular detection medium in rare-event searches, liquid xenon, with a new, background-free material, graphene. Our baseline design of GraXe is a balloon made of graphene (possibly held together with a very thin structure made of radiopure fiber) and filled with xenon enriched in the Xe-136 isotope. The balloon is immersed in a large tank containing 20 tons of natural liquid xenon and instrumented with large photomultipliers. Liquid xenon is an excellent scintillator, reasonably transparent to its own light. Graphene is transparent over a large frequency range, an impermeable to the xenon. External backgrounds would be shielded by the buffer liquid xenon, and the inner volume has virtually zero background. Industrial graphene can be manufactured at a competitive cost to produce the inner balloon, and there is already near one ton of enriched Xenon available in the world...

  17. XENON1T radon assay

    Energy Technology Data Exchange (ETDEWEB)

    Bruenner, Stefan [MPIK, Heidelberg (Germany); Collaboration: XENON-Collaboration

    2016-07-01

    The radioactive isotope {sup 222}Rn is one of the most dominant intrinsic background sources for experiments dealing with a low event rate like the XENON1T Dark Matter detector. Being part of the primordial decay chain of {sup 238}U the noble gas {sup 222}Rn permanently emanates from almost all materials. Therefore, it is crucial to determine the radon emanation rate of those detector components that will be in contact with the xenon target. The technique of the radon emanation measurements, making use of ultra low background proportional counters is presented as well as selected results for XENON1T.

  18. Electric dipole moment searches using the isotope 129-xenon

    Energy Technology Data Exchange (ETDEWEB)

    Kuchler, Florian

    2014-11-13

    Two new complementary experiments searching for a permanent electric dipole moment (EDM) of 129-xenon are presented. Besides demonstration of a sensitivity improvement by employing established methods and a highly sensitive SQUID detection system the progress towards a novel measurement approach is discussed. The new method introduces time-varying electric fields and a liquid hyper-polarized xenon sample with a potential improvement in sensitivity of three orders of magnitude. The search for EDMs is motivated by their symmetry-breaking nature. A non-zero EDM provides a new source of CP violation to solve the mystery of the huge excess of matter over anti-matter in our Universe.

  19. Xenon purity analysis for EXO-200 via mass spectrometry

    CERN Document Server

    Dobi, A; Slutsky, S; Yen, Y -R; Aharmin, B; Auger, M; Barbeau, P S; Benitez-Medina, C; Breidenbach, M; Cleveland, B; Conley, R; Cook, J; Cook, S; Counts, I; Craddock, W; Daniels, T; Davis, C G; Davis, J; deVoe, R; Dixit, M; Dolinski, M J; Donato, K; Fairbank, W; Farine, J; Fierlinger, P; Franco, D; Giroux, G; Gornea, R; Graham, K; Gratta, G; Green, C; Hagemann, C; Hall, K; Hallman, D; Hargrove, C; Herrin, S; Hughes, M; Hodgson, J; Juget, F; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K; Leonard, D S; Lutter, G; Mackay, D; MacLellan, R; Marino, M; Mong, B; Díez, M Montero; Morgan, P; Müller, A R; Neilson, R; Odian, A; O'Sullivan, K; Piepke, A; Pocar, A; Prescott, C Y; Pushkin, K; Rivas, A; Rollin, E; Rowson, P C; Sabourov, A; Sinclair, D; Skarpaas, K; Stekhanov, V; Strickland, V; Swift, M; Twelker, K; Vuilleumier, J -L; Vuilleumier, J -M; Weber, M; Wichoski, U; Wodin, J; Wright, J D; Yang, L

    2011-01-01

    We describe purity measurements of the natural and enriched xenon stockpiles used by the EXO-200 double beta decay experiment based on a mass spectrometry technique. The sensitivity of the spectrometer is enhanced by several orders of magnitude by the presence of a liquid nitrogen cold trap, and many impurity species of interest can be detected at the level of one part-per-billion or better. We have used the technique to screen the EXO-200 xenon before, during, and after its use in our detector, and these measurements have proven useful. This is the first application of the cold trap mass spectrometry technique to an operating physics experiment.

  20. Characterization of recombination effects in a liquid ionization chamber used for the dosimetry of a radiosurgical accelerator.

    Science.gov (United States)

    Wagner, Antoine; Crop, Frederik; Lacornerie, Thomas; Reynaert, Nick

    2014-05-09

    Most modern radiation therapy devices allow the use of very small fields, either through beamlets in Intensity-Modulated Radiation Therapy (IMRT) or via stereotactic radiotherapy where positioning accuracy allows delivering very high doses per fraction in a small volume of the patient. Dosimetric measurements on medical accelerators are conventionally realized using air-filled ionization chambers. However, in small beams these are subject to nonnegligible perturbation effects. This study focuses on liquid ionization chambers, which offer advantages in terms of spatial resolution and low fluence perturbation. Ion recombination effects are investigated for the microLion detector (PTW) used with the Cyberknife system (Accuray). The method consists of performing a series of water tank measurements at different source-surface distances, and applying corrections to the liquid detector readings based on simultaneous gaseous detector measurements. This approach facilitates isolating the recombination effects arising from the high density of the liquid sensitive medium and obtaining correction factors to apply to the detector readings. The main difficulty resides in achieving a sufficient level of accuracy in the setup to be able to detect small changes in the chamber response.

  1. New constraints and prospects for sub-GeV dark matter scattering off electrons in xenon

    Science.gov (United States)

    Essig, Rouven; Volansky, Tomer; Yu, Tien-Tien

    2017-08-01

    We study in detail sub-GeV dark matter scattering off electrons in xenon, including the expected electron recoil spectra and annual modulation spectra. We derive improved constraints using low-energy XENON10 and XENON100 ionization-only data. For XENON10, in addition to including electron-recoil data corresponding to about 1-3 electrons, we include for the first time events corresponding to about 4-7 electrons. Assuming the scattering is momentum independent (FDM=1 ), this strengthens a previous cross-section bound by almost an order of magnitude for dark matter masses above 50 MeV. The available XENON100 data corresponds to events with about 4-50 electrons, and leads to a constraint that is comparable to the XENON10 bound above 50 MeV for FDM=1 . We demonstrate that a search for an annual modulation signal in upcoming xenon experiments (XENON1T, XENONnT, LZ) could substantially improve the above bounds even in the presence of large backgrounds. We also emphasize that in simple benchmark models of sub-GeV dark matter, the dark matter-electron scattering rate can be as high as one event every ten (two) seconds in the XENON1T (XENONnT or LZ) experiments, without being in conflict with any other known experimental bounds. While there are several sources of backgrounds that can produce single- or few-electron events, a large event rate can be consistent with a dark matter signal and should not be simply written off as purely a detector curiosity. This fact motivates a detailed analysis of the ionization-data ("S2") data, taking into account the expected annual modulation spectrum of the signal rate, as well as the DM-induced electron-recoil spectra, which are another powerful discriminant between signal and background.

  2. Evaluation of the ionization quenching correction for several liquid scintillators; Evaluacion de la extincion por ionizacion para diversos liquidos centelleadores

    Energy Technology Data Exchange (ETDEWEB)

    Los Arcos, J. M.; Borras, C.

    1990-07-01

    The most appropriate computational model for the ionization quenching function Q(E) is analyzed for electrons in liquid scintillators. A numerical evaluation of Q(E) from 0.1 keV to 3 MeV which the kB parameter varying between 0.005 and 0.010 cm/MeV is presented for seven scintillators; Toluene, Toluene-Alcohol, PCS, Toluene-CCl4, INSTAGEL, Dioxane-Naphtalene and HISAFE II. The numerical result are summarized as tables of Ieast squares fitting coefficient which make easy the computation of Q(E). (Author)

  3. Identification of Ceftiofur Oxidation Products by High-Performance Liquid Chromatography/Electrospray Ionization/Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Hye-Sung Cho

    2011-03-01

    Full Text Available Oxidation products of ceftiofur were formed in hydrogen peroxide solution. The structures of the ceftiofur oxidationproducts were characterized by high-performance liquid chromatography/electrospray ionization/tandem mass spectrometry(HPLC/ESI/MS/MS. The products were identified as compounds oxidized at the sulfur of a cephem ring. For further analysis,experiments were performed using O18-labeled hydrogen peroxide. In addition, density-functional calculations were carried out forsix possible oxidation products to support the experimental results.

  4. Evaluation of dosimetric characteristics of multi-leaf and conventional collimated radiation fields using a scanning liquid ionization chamber EPID.

    Science.gov (United States)

    Mohammadi, M; Bezak, E

    2008-12-01

    The characteristics of radiation fields set up using conventional and Multi-Leaf collimators were investigated using a Scanning Liquid Ionization Chamber Electronic Portal Imaging Device (SLIC-EPID). Results showed that the radiation fields set up using MLCs are generally larger than those set up using conventional collimators. A significant difference was observed between the penumbra width for conventional and MLC radiation fields. SLIC-EPID was found to be a sensitive device to evaluate the characteristics of the radiation fields generated with MLCs.

  5. A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization

    CERN Document Server

    Rossi, B; Ereditato, A; Haug, S; Hanni, R; Hess, M; Janos, S; Juget, F; Kreslo, I; Lehmann, S; Lutz, P; Mathieu, R; Messina, M; Moser, U; Nydegger, F; Schutz, H U; Weber, M S; Zeller, M

    2009-01-01

    This paper describes the design, realization and operation of a prototype liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the development of a novel online monitoring and calibration system exploiting UV laser beams. In particular, the system is intended to measure the lifetime of the primary ionization in LAr, in turn related to the LAr purity level. This technique could be exploited by present and next generation large mass LAr TPCs for which monitoring of the performance and calibration plays an important role. Results from the first measurements are presented together with some considerations and outlook.

  6. Separation and characterization of phenolic compounds in fennel (Foeniculum vulgare) using liquid chromatography-negative electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Parejo, Irene; Jauregui, Olga; Sánchez-Rabaneda, Ferran; Viladomat, Francesc; Bastida, Jaume; Codina, Carles

    2004-06-16

    Liquid chromatography (LC) diode array detection (DAD) coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for the rapid and sensitive identification of water-soluble phenolic compounds in fennel waste. The plant material was first extracted and then chromatographed on Sephadex LH-20 to afford seven fractions, each of them being subjected to LC-MS analysis. Identification of the compounds was carried out by interpretation of UV, MS, and MS/MS spectra. Forty-two phenolic substances were identified, 27 of which had not previously been reported in fennel, including hydroxycinnamic acid derivatives, flavonoid glycosides, and flavonoid aglycons.

  7. Liquid chromatography electrospray ionization and matrix-assisted laser desorption ionization tandem mass spectrometry for the analysis of lipid raft proteome of monocytes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Nan [Department of Chemistry, University of Alberta, Edmonton, Alberta (Canada); Shaw, Andrew R.E. [Department of Chemistry, University of Alberta, Edmonton, Alberta (Canada)], E-mail: andrewsh@cancerboard.ab.ca; Li Nan; Chen Rui [Department of Chemistry, University of Alberta, Edmonton, Alberta (Canada); Mak, Allan; Hu Xiuying [Department of Oncology, University of Alberta, Edmonton, Alberta (Canada); Young, Nelson; Wishart, David [Department of Computing Science, University of Alberta, Edmonton, Alberta (Canada); Li Liang, E-mail: Liang.Li@ualberta.ca

    2008-10-03

    Lipid rafts are dynamic assemblies of cholesterol and glycolipid that form detergent-insoluble microdomains within membrane lipid bilayers. Because rafts can be separated by flotation on sucrose gradients, interrogation by mass spectrometry (MS) provides a valuable new insight into lipid raft function. Here we combine liquid chromatography (LC) electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) MS/MS to corroborate and extend our previous description of lipid raft proteomes derived from the monocytic cell line THP-1. Interestingly, LC-ESI and MALDI MS/MS identify largely non-overlapping, and therefore, potentially complementary protein populations. Using the combined approach, we detected 277 proteins compared to 52 proteins obtained with the original gel-based MALDI MS. We confirmed the presence of 47 of the original 52 proteins demonstrating the consistency of the lipid raft preparations. We demonstrated by immunoblotting that Rac 1 and Rac 2, two of the 52 proteins we failed to confirm, were indeed absent from the lipid raft fractions. The majority of new proteins were cytoskeletal proteins and their regulators, proteins implicated in membrane fusion and vesicular trafficking or signaling molecules. Our results therefore, confirm and extend previous evidence indicating lipid rafts of monocytic cells are specialized for cytoskeletal assembly and vesicle trafficking. Of particular interest, we detected SNAP-23, basigin, Glut-4 and pantophysin in lipid rafts. Since these proteins are implicated in both vesicular trafficking and gamete fusion, lipid rafts may play a common role in these processes. It is evident that the combination of LC-ESI and LC-MALDI MS/MS increases the proteome coverage which allows better understanding of the lipid raft function.

  8. Experimental assessment of on-chip liquid cooling through microchannels with de-ionized water and diluted ethylene glycol

    Science.gov (United States)

    Won, Yonghyun; Kim, Sungdong; Eunkyung Kim, Sarah

    2016-06-01

    Recent progress in Si IC devices, which results in an increase in power density and decrease in device size, poses various thermal challenges owing to high heat dissipation. Therefore, conventional cooling techniques become ineffective and produce a thermal bottleneck. In this study, an on-chip liquid cooling module with microchannels and through Si via (TSV) was fabricated, and cooling characteristics were evaluated by IR measurements. Both the microchannels and TSVs were fabricated in a Si wafer by deep reactive ion etching (DRIE) and the wafer was bonded with a glass wafer by a anodic bonding. The fabricated liquid cooling sample was evaluated using two different coolants (de-ionized water and 70 wt % diluted ethylene glycol), and the effect of coolants on cooling characteristics was investigated.

  9. Modeling Pulse Characteristics in Xenon with NEST

    CERN Document Server

    Mock, Jeremy; Kazkaz, Kareem; Szydagis, Matthew; Tripathi, Mani; Uvarov, Sergey; Woods, Michael; Walsh, Nicholas

    2013-01-01

    A comprehensive model for describing the characteristics of pulsed signals, generated by particle interactions in xenon detectors, is presented. An emphasis is laid on two-phase time projection chambers, but the models presented are also applicable to single phase detectors. In order to simulate the pulse shape due to primary scintillation light, effects such as the ratio of singlet and triplet dimer state populations, as well as their corresponding decay times, and the recombination time are incorporated into the model. In a two phase time projection chamber, when simulating the pulse caused by electroluminescence light, parameters such as ionization electron mean free path in gas, the drift velocity, singlet and triplet decay times, diffusion constants, and the electron trapping time, have been implemented. This modeling has been incorporated into a complete software package, which realistically simulates the expected pulse shapes for these types of detectors.

  10. In situ liquid-liquid extraction as a sample preparation method for matrix-assisted laser desorption/ionization MS analysis of polypeptide mixtures

    DEFF Research Database (Denmark)

    Kjellström, Sven; Jensen, Ole Nørregaard

    2003-01-01

    A novel liquid-liquid extraction (LLE) procedure was investigated for preparation of peptide and protein samples for matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). LLE using ethyl acetate as the water-immiscible organic solvent enabled segregation of hydrophobic...... matrix to the organic solvent enhanced the efficiency of the LLE-MALDI MS method for analysis of hydrophobic peptides and proteins. LLE-MALDI MS enabled the detection of the hydrophobic membrane protein bacteriorhodopsin as a component in a simple protein mixture. Peptide mixtures containing...... phosphorylated, glycosylated, or acylated peptides were successfully separated and analyzed by the in situ LLE-MALDI MS technique and demonstrate the potential of this method for enhanced separation and structural analysis of posttranslationally modified peptides in proteomics research....

  11. Application of elevated temperature-dispersive liquid-liquid microextraction for determination of organophosphorus pesticides residues in aqueous samples followed by gas chromatography-flame ionization detection.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Afshar Mogaddam, Mohammad Reza; Rezaee Aghdam, Samaneh; Nouri, Nina; Bamorrowat, Mahdi

    2016-12-01

    In the present study, an elevated temperature, dispersive, liquid-liquid microextraction/gas chromatography-flame ionization detection was investigated for the determination, pre-concentration, and extraction of six organophosphorus pesticides (malathion, phosalone, dichlorvos, diazinon, profenofos, and chlorpyrifos) residues in fruit juice and aqueous samples. A mixture of 1,2-dibromoethane (extraction solvent) and dimethyl sulfoxide (disperser solvent) was injected rapidly into the sample solution heated at an elevated temperature. Analytical parameters, including enrichment factors (1600-2075), linearity (r>0.994), limits of detection (0.82-2.72ngmL(-1)) and quantification (2.60-7.36ngmL(-1)), relative standard deviations (<7%) and extraction recoveries (64-83%), showed the high efficiency of the method developed for analysis of the target analytes. The proposed procedure was used effectively to analyse selected analytes in river water and fruit juice, and diazinon was found at ngmL(-1) concentrations in apple juice.

  12. Identification of multiply charged proteins and amino acid clusters by liquid nitrogen assisted spray ionization mass spectrometry.

    Science.gov (United States)

    Kumar Kailasa, Suresh; Hasan, Nazim; Wu, Hui-Fen

    2012-08-15

    The development of liquid nitrogen assisted spray ionization mass spectrometry (LNASI MS) for the analysis of multiply charged proteins (insulin, ubiquitin, cytochrome c, α-lactalbumin, myoglobin and BSA), peptides (glutathione, HW6, angiotensin-II and valinomycin) and amino acid (arginine) clusters is described. The charged droplets are formed by liquid nitrogen assisted sample spray through a stainless steel nebulizer and transported into mass analyzer for the identification of multiply charged protein ions. The effects of acids and modifier volumes for the efficient ionization of the above analytes in LNASI MS were carefully investigated. Multiply charged proteins and amino acid clusters were effectively identified by LNASI MS. The present approach can effectively detect the multiply charged states of cytochrome c at 400 nM. A comparison between LNASI and ESI, CSI, SSI and V-EASI methods on instrumental conditions, applied temperature and observed charge states for the multiply charged proteins, shows that the LNASI method produces the good quality spectra of amino acid clusters at ambient conditions without applied any electric field and heat. To date, we believe that the LNASI method is the most simple, low cost and provided an alternative paradigm for production of multiply charged ions by LNASI MS, just as ESI-like ions yet no need for applying any electrical field and it could be operated at low temperature for generation of highly charged protein/peptide ions.

  13. Chemical Investigation of Saponins in Different Parts of Panax notoginseng by Pressurized Liquid Extraction and Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Si-Jia Hong

    2012-05-01

    Full Text Available A pressurized liquid extraction (PLE and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS method was developed for the qualitative determination of saponins in different parts of P. notoginseng, including rhizome, root, fibre root, seed, stem, leaf and flower. The samples were extracted using PLE. The analysis was achieved on a Zorbax SB-C18 column with gradient elution of acetonitrile and 8 mM aqueous ammonium acetate as mobile phase. The mass spectrometer was operated in the negative ion mode using the electrospray ionization, and a collision induced dissociation (CID experiment was also carried out to aid the identification of compounds. Forty one saponins were identified in different parts of P. notoginseng according to the fragmentation patterns and literature reports, among them, 21 saponins were confirmed by comparing the retention time and ESI-MS data with those of standard compounds. The results showed that the chemical characteristics were obviously diverse in different parts of P. notoginseng, which is helpful for pharmacological evaluation and quality control of P. notoginseng.

  14. Charge States of Krypton and Xenon in the Solar Wind

    Science.gov (United States)

    Bochsler, Peter; Fludra, Andrzej; Giunta, Alessandra

    2017-09-01

    We calculate charge state distributions of Kr and Xe in a model for two different types of solar wind using the effective ionization and recombination rates provided from the OPEN_ADAS data base. The charge states of heavy elements in the solar wind are essential for estimating the efficiency of Coulomb drag in the inner corona. We find that xenon ions experience particularly low Coulomb drag from protons in the inner corona, comparable to the notoriously weak drag of protons on helium ions. It has been found long ago that helium in the solar wind can be strongly depleted near interplanetary current sheets, whereas coronal mass ejecta are sometimes strongly enriched in helium. We argue that if the extraordinary variability of the helium abundance in the solar wind is due to inefficient Coulomb drag, the xenon abundance must vary strongly. In fact, a secular decrease of the solar wind xenon abundance relative to the other heavier noble gases (Ne, Ar, Kr) has been postulated based on a comparison of noble gases in recently irradiated and ancient samples of ilmenite in the lunar regolith. We conclude that decreasing solar activity and decreasing frequency of coronal mass ejections over the solar lifetime might be responsible for a secularly decreasing abundance of xenon in the solar wind.

  15. Simultaneous derivatization and air-assisted liquid-liquid microextraction of some parabens in personal care products and their determination by GC with flame ionization detection.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Khosrowshahi, Elnaz Marzi; Khorram, Parisa

    2013-11-01

    A simultaneous derivatization/air-assisted liquid-liquid microextraction technique has been developed for the sample pretreatment of some parabens in aqueous samples. The analytes were derivatized and extracted simultaneously by a fast reaction/extraction with butylchloroformate (derivatization agent/extraction solvent) from the aqueous samples and then analyzed by GC with flame ionization detection. The effect of catalyst type and volume, derivatization agent/extraction solvent volume, ionic strength of aqueous solution, pH, numbers of extraction, aqueous sample volume, etc. on the method efficiency was investigated. Calibration graphs were linear in the range of 2-5000 μg/L with squared correlation coefficients >0.990. Enhancement factors and enrichment factors ranged from 1535 to 1941 and 268 to 343, respectively. Detection limits were obtained in the range of 0.41-0.62 μg/L. The RSDs for the extraction and determination of 250 μg/L of each paraben were <4.9% (n = 6). In this method, the derivatization agent and extraction solvent were the same and there is no need for a dispersive solvent, which is common in a traditional dispersive liquid-liquid microextraction technique. Furthermore, the sample preparation time is very short.

  16. Irradiated Xenon Isotopic Ratio Measurement for Failed Fuel Detection and Location in Fast Reactor

    Science.gov (United States)

    Ito, Chikara; Iguchi, Tetsuo; Harano, Hideki

    2009-08-01

    The accuracy of xenon isotopic ratio burn-up calculations used for failed fuel identification was evaluated by an irradiation test of xenon tag gas samples in the Joyo test reactor. The experiment was carried out using pressurized steel capsules containing unique blend ratios of stable xenon tag gases in an on-line creep rupture experiment in Joyo. The tag gas samples were irradiated to total neutron fluences of 1.6 to 4.8 × 1026 n/m2. Laser resonance ionization mass spectrometry was used to analyze the cover gas containing released tag gas diluted to isotopic ratios of 100 to 102 ppb. The isotopic ratios of xenon tag gases after irradiation were calculated using the ORIGEN2 code. The neutron cross sections of xenon nuclides were based on the JENDL-3.3 library. These cross sections were collapsed into one group using the neutron spectra of Joyo. The comparison of measured and calculated xenon isotopic ratios provided C/E values that ranged from 0.92 to 1.10. The differences between calculation and measurement were considered to be mainly due to the measurement errors and the xenon nuclide cross section uncertainties.

  17. Development of a functionalized Xenon biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Spence, Megan M.; Ruiz, E. Janette; Rubin, Seth M.; Lowery, Thomas J.; Winssinger, Nicolas; Schultz, Peter G.; Wemmer, David E.; Pines, Alexander

    2004-03-25

    NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon chemical shift, which is a key requirement for being able to multiplex the biosensor.

  18. Development of a functionalized Xenon biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Spence, Megan M.; Ruiz, E. Janette; Rubin, Seth M.; Lowery, Thomas J.; Winssinger, Nicolas; Schultz, Peter G.; Wemmer, David E.; Pines, Alexander

    2004-03-25

    NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon chemical shift, which is a key requirement for being able to multiplex the biosensor.

  19. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    CERN Document Server

    Troyer, G L

    2000-01-01

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% (at) 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse r...

  20. Barium Tagging in Solid Xenon for the nEXO Experiment

    Science.gov (United States)

    Chambers, Christopher; Craycraft, Adam; Walton, Timothy; Fairbank, William; nEXO Collaboration

    2016-09-01

    The proposed nEXO experiment utilizes a tonne-scale liquid xenon time projection chamber to search for neutrinoless double beta decay in xenon-136. Positive observation of this decay would determine the nature of the neutrino to be a MAJORANA particle, as well as measure the absolute neutrino mass scale. A critical concern for any rare decay search is reducing or eliminating backgrounds that cannot be distinguished from signal. A powerful background discrimination technique is positive identification of the daughter atom of the decay, in this case barium. This technique, called ``barium tagging'' may be available for a second phase of nEXO operation, allowing for neutrino mass sensitivity beyond the inverted mass hierarchy. Development is underway on a scheme to capture the barium daughter in solid xenon with a cryogenic probe and detect the barium by laser-induced fluorescence inside the solid xenon sample. This presentation reports results on imaging of single barium atoms frozen in a solid xenon matrix, as well as the progress on the freezing and removal of a solid xenon sample from liquid xenon. Graduated.

  1. Removing krypton from xenon by cryogenic distillation to the ppq level

    Energy Technology Data Exchange (ETDEWEB)

    Aprile, E.; Anthony, M.; De Perio, P.; Gao, F.; Goetzke, L.W.; Greene, Z.; Messina, M.; Plante, G.; Rizzo, A.; Zhang, Y. [Columbia University, Physics Department, New York, NY (United States); Aalbers, J.; Breur, P.A.; Brown, A.; Colijn, A.P.; Decowski, M.P.; Hogenbirk, E.; Tiseni, A. [Nikhef and the University of Amsterdam, Science Park, Amsterdam (Netherlands); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso (Italy); Gran Sasso Science Institute, L' Aquila (Italy); University of Bologna, Department of Physics and Astrophysics, Bologna (Italy); INFN-Bologna (Italy); Alfonsi, M.; Geis, C.; Grignon, C.; Oberlack, U.; Scheibelhut, M.; Schindler, S. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Amaro, F.D.; Cardoso, J.M.R.; Lopes, J.A.M.; Orrigo, S.E.A.; Santos, J.M.F. dos; Silva, M. [University of Coimbra, Department of Physics, Coimbra (Portugal); Arneodo, F.; Benabderrahmane, M.L.; Di Giovanni, A.; Maris, I. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Barrow, P.; Baudis, L.; Franco, D.; Galloway, M.; Kessler, G.; Kish, A.; Mayani, D.; Pakarha, P.; Piastra, F.; Wei, Y.; Wulf, J. [Physik-Institut, University of Zurich, Zurich (Switzerland); Bauermeister, B. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Stockholm University, AlbaNova, Oskar Klein Centre, Department of Physics, Stockholm (Sweden); Berger, T.; Brown, E.; Piro, M.C. [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy, Troy, NY (United States); Bruenner, S.; Cichon, D.; Eurin, G.; Hasterok, C.; Lindemann, S.; Lindner, M.; Undagoitia, T.M.; Pizzella, V.; Rauch, L.; Rupp, N.; Schreiner, J.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bruno, G.; Gallo Rosso, A.; Molinario, A. [INFN-Laboratori Nazionali del Gran Sasso (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Budnik, R.; Duchovni, E.; Itay, R.; Landsman, H.; Lellouch, D.; Levinson, L.; Manfredini, A.; Priel, N. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); Buetikofer, L.; Coderre, D.; Kaminsky, B.; Schumann, M.; Sivers, M. v. [Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Calven, J.; Conrad, J.; Ferella, A.D.; Pelssers, B. [Stockholm University, AlbaNova, Oskar Klein Centre, Department of Physics, Stockholm (Sweden); Cervantes, M.; Lang, R.F.; Masson, D.; Pienaar, J.; Reichard, S.; Reuter, C. [Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); Cussonneau, J.P.; Diglio, S.; Le Calloch, M.; Masbou, J.; Micheneau, K.; Persiani, R.; Thers, D. [Universite de Nantes, SUBATECH, Ecole des Mines de Nantes, CNRS/In2p3, Nantes (France); Di Gangi, P.; Garbini, M.; Massoli, F.V.; Sartorelli, G.; Selvi, M. [University of Bologna, Department of Physics and Astrophysics, Bologna (Italy); INFN-Bologna (Italy); Fei, J.; Ni, K.; Ye, J. [University of California, Department of Physics, San Diego, CA (United States); Fieguth, A.; Huhmann, C.; Murra, M.; Rosendahl, S.; Weinheimer, C. [Westfaelische Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Fulgione, W. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); INFN-Torino (Italy); Osservatorio Astrofisico di Torino, Torino (Italy); Grandi, L.; Saldanha, R.; Shockley, E.; Upole, N. [University of Chicago, Department of Physics and Kavli Institute of Cosmological Physics, Chicago, IL (United States); Lin, Q. [Laboratori Nazionali del Gran Sasso, Assergi (Italy); Meng, Y.; Stein, A.; Wang, H. [University of California, Physics and Astronomy Department, Los Angeles, CA (United States); Miguez, B.; Trinchero, G. [INFN-Torino (Italy); Osservatorio Astrofisico di Torino, Torino (Italy); Naganoma, J.; Shagin, P. [Rice University, Department of Physics and Astronomy, Houston, TX (United States); Lavina, L.S. [LPNHE, Universite Pierre et Marie Curie, Universite Paris Diderot, CNRS/IN2P3, Paris (France); Tunnell, C. [Nikhef and the University of Amsterdam, Science Park, Amsterdam (Netherlands); University of Chicago, Department of Physics and Kavli Institute of Cosmological Physics, Chicago, IL (United States); Cristescu, I. [Karlsruhe Institute of Technology, Tritium Laboratory Karlsruhe, Eggenstein-Leopoldshafen (Germany); Collaboration: XENON Collaboration

    2017-05-15

    The XENON1T experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β-emitter {sup 85}Kr which is present in the xenon. For XENON1T a concentration of natural krypton in xenon {sup nat}Kr/Xe < 200 ppq (parts per quadrillion, 1 ppq = 10{sup -15} mol/mol) is required. In this work, the design, construction and test of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4 . 10{sup 5} with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of {sup nat}Kr/Xe < 26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN. (orig.)

  2. High-pressure xenon detector development at Constellation Technology Corporation

    Energy Technology Data Exchange (ETDEWEB)

    Austin, Robert A. [Constellation Technology Corporation, 7887 Bryan Dairy Road, Suite 100, Largo, FL 33777 (United States)], E-mail: austin@contech.com

    2007-08-21

    Xenon-filled ionization detectors, due to their high atomic number fill gas (Z=54), moderate densities ({approx}0.3-0.5 g/cm{sup 3}) and good energy resolution (2-4% at 662 keV), fill an important niche between more familiar technologies such as NaI(Tl) scintillators and germanium detectors. Until recently, difficulties with obtaining sufficient xenon purity, reducing microphonic sensitivity, and developing low-noise electronics compatible with small ionization signals have hampered the development of this nuclear detection field. Constellation Technology Corporation, whose experience with xenon detectors goes back to the mid 1990s, has made significant progress in these areas and has developed a commercial line of detectors with active volumes ranging from small (35 g Xe) to large (1400 g Xe). Current applications for Constellation's detectors are principally in the area of defense (Unmanned Aerial Vehicles and Advanced Spectroscopic Portals), but as awareness of this technology grows, it will surely find applications in a much expanded range of fields.

  3. High-pressure xenon detector development at Constellation Technology Corporation

    Science.gov (United States)

    Austin, Robert A.

    2007-08-01

    Xenon-filled ionization detectors, due to their high atomic number fill gas ( Z=54), moderate densities (˜0.3-0.5 g/cm 3) and good energy resolution (2-4% at 662 keV), fill an important niche between more familiar technologies such as NaI(Tl) scintillators and germanium detectors. Until recently, difficulties with obtaining sufficient xenon purity, reducing microphonic sensitivity, and developing low-noise electronics compatible with small ionization signals have hampered the development of this nuclear detection field. Constellation Technology Corporation, whose experience with xenon detectors goes back to the mid 1990s, has made significant progress in these areas and has developed a commercial line of detectors with active volumes ranging from small (35 g Xe) to large (1400 g Xe). Current applications for Constellation's detectors are principally in the area of defense (Unmanned Aerial Vehicles and Advanced Spectroscopic Portals), but as awareness of this technology grows, it will surely find applications in a much expanded range of fields.

  4. Measurement of Low Energy Electronic Recoil Response and Electronic/Nuclear Recoils Discrimination in XENON100

    Science.gov (United States)

    Ye, Jingqiang; Xenon Collaboration

    2017-01-01

    The XENON100 detector uses liquid xenon time projection chamber to search for nuclear recoils(NR) caused by hypothetical Weakly Interacting Massive Particles (WIMPs). The backgrounds are mostly electronic recoils(ER), thus it's crucial to distinguish NR from ER. Using high statistical calibration data from tritiated methane, AmBe and other sources in XENON100, the ER/NR discrimination under different electric fields are measured. The Photon yield and recombination fluctuation of low energy electronic recoils under different fields will also be presented and compared to results from NEST and other experiments, which is crucial to understanding the response of liquid xenon detectors in the energy regime of searching dark matter.

  5. Xenon-based anesthesia: theory and practice

    OpenAIRE

    Jan-Hinrich Baumert

    2009-01-01

    Jan-Hinrich BaumertDept of Anaesthesiology, UMC St Radboud, Nijmegen, NetherlandsAbstract: Xenon has been in use as an anesthetic for more than 50 years. Although it exhibits some of the properties of an ideal anesthetic, the technical complexity of xenon equipment and the high cost of the gas have prevented widespread use of xenon anesthesia. The main beneficial features of xenon anesthesia are fast induction and emergence because of low solubility in blood and tissues, along with remarkably...

  6. High-performance liquid chromatography-electrospray ionization tandem mass spectrometry for metabolism study of timosaponin AIII.

    Science.gov (United States)

    Jia, Yao; Wu, Bin; Fan, Mingsong; Wang, Jinhui; Huang, Jian; Huang, Chenggang

    2014-01-01

    A sensitive method based on high-performance liquid chromatography-electrospray ionization tandem mass spectrometry was developed for the determination of timosaponin AIII (TA3) and its in vivo and in vitro metabolites. The rat plasma, urine, feces and tissue samples were collected after oral administration of TA3 at a single dose of 300 mg/kg. TA3 was incubated into artificial gastric juice and artificial intestinal juice. The in vivo and in vitro samples were purified by using liquid-liquid extraction. The structures of metabolites were elucidated by comparing their molecular weights, retention times and tandem mass spectrometric spectra with those of the parent drug. As a result, four metabolites (deglycosylated TA3, two hydroxylated TA3 and timosaponin BII) and the parent drug were found in in vivo and in vitro samples. In addition to the parent drug, one, one and two metabolites were identified in heart, urine and feces, respectively. Only the parent drug was detected in plasma, liver and kidney. One hydroxylation metabolite and TA3 were identified from incubation samples with AGJ, whereas two hydroxylation metabolites and TA3 were detected from the incubation with AIJ. This is the first systematic metabolism study of TA3. The biotransformation pathways of TA3 primarily included deglycosylation, hydroxylation and glycosylation.

  7. Quantification of roxatidine in human plasma by liquid chromatography electrospray ionization tandem mass spectrometry: application to a bioequivalence study.

    Science.gov (United States)

    Ryu, Ju-Hee; Choi, Sang-Jun; Lee, Heon-Woo; Choi, Seung-Ki; Lee, Kyung-Tae

    2008-12-01

    A sensitive and specific method using a one-step liquid-liquid extraction (LLE) with ethyl acetate followed by high-performance liquid chromatography (HPLC) coupled with positive ion electrospray ionization tandem mass spectrometry (ESI-MS/MS) detection was developed and validated for the determination of roxatidine in human plasma using famotidine as an internal standard (IS). Data acquisition was carried out in multiple reaction monitoring (MRM) mode, by monitoring the transitions m/z 307.3-->107.1 for roxatidine and m/z 338.4-->189.1 for famotidine. Chromatographic separation was performed on a reverse phase Hydrosphere C(18) column at 0.2 mL min(-1) using a mixture of methanol-ammonium formate buffer as mobile phase (20:80, v/v; adjusted to pH 3.9 with formic acid). The achieved lower limit of quantification (LLOQ) was 1.0 ng mL(-1) and the standard calibration curve for roxatidine was linear (r(2)=0.998) over the studied range (1-1000 ng mL(-1)) with acceptable accuracy and precision. Roxatidine was found to be stable in human plasma samples under short-, long-term storage and processing conditions. The developed method was validated and successfully applied to the bioequivalence study of roxatidine administrated as a single oral dose (75 mg as roxatidine acetate hydrochloride) to healthy female Korean volunteers.

  8. Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The phosphorylation sites of two phosphorylated proteins, bovine b-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

  9. Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    车发云; 邵晓霞; 夏其昌

    2000-01-01

    The phosphorylation sites of two phosphorylated proteins, bovine β-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

  10. Identification of Phenylethanoid Glycosides in Plant Extract of Plantago asiatica L. by Liquid Chromatography-Electrospray Ionization Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LI,Li; LIU,Chunming; LIU,Zhiqiang; TSAO,Rong; LIU,Shuying

    2009-01-01

    The present work describes a liquid chromatography-electrospray ionization mass spectrometry(LC-ESI-MS)method for rapid identification of phenylethanoid glycosides in plant extract from Plnmgo asiatica L.By using a binary mobile phase system consisting of 0.2% acetic acid and acetonitrile under gradient conditions,a good sepa-ration was achieved on a reversed-phase C18 column.The[M-H] ions,the molecular weights,and the fragmentions of phenvlethanoid glycosides were obtained in the negative ion mode using LC-ESI-MS.The identification of the phenylethanoid glycosides(peaks 1-3) in the extract of P. asiatica L.was based on matching their retention time.the detection of molecular ions.and the fragment ions obtained by collision-induced dissociation(CID)ex-periments with those of the authentic standards and data reported in the literature.

  11. Comparative analysis of different plant oils by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

    Science.gov (United States)

    Jakab, Annamaria; Héberger, Károly; Forgács, Esther

    2002-11-01

    Different vegetable oil samples (almond, avocado, corngerm, grapeseed, linseed, olive, peanut, pumpkin seed, soybean, sunflower, walnut, wheatgerm) were analyzed using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. A gradient elution technique was applied using acetone-acetonitrile eluent systems on an ODS column (Purospher, RP-18e, 125 x 4 mm, 5 microm). Identification of triacylglycerols (TAGs) was based on the pseudomolecular ion [M+1]+ and the diacylglycerol fragments. The positional isomers of triacylglycerol were identified from the relative intensities of the [M-RCO2]+ fragments. Linear discriminant analysis (LDA) as a common multivariate mathematical-statistical calculation was successfully used to distinguish the oils based on their TAG composition. LDA showed that 97.6% of the samples were classified correctly.

  12. Quantitative analysis of triglyceride species of vegetable oils by high performance liquid chromatography via a flame ionization detector.

    Science.gov (United States)

    Phillips, F C; Erdahl, W L; Schmit, J A; Privett, O S

    1984-11-01

    A method for the quantitative analysis of triglyceride species composition of vegetable oils by reversed-phase high performance liquid chromatography (RP-HPLC) via a flame ionization detector (FID) is described. Triglycerides are separated into molecular species via Zorbax chemically bonded octadecylsilane (ODS) columns using gradient elution with methylene chloride in acetonitrile. Identification of species is made by matching the retention times of the peaks in the chromatogram with the order of elution of all of the species that could be present in the sample on the basis of a random distribution of the fatty acids and comparison of experimental and calculated theoretical carbon numbers (TCN). Quantitative analysis is based on a direct proportionality of peak areas. Differences in the response of individual species were small and did not dictate the use of response factors. The method is applied to cocoa butter before and after randomization, soybean oil and pure olive oil.

  13. The analysis of high explosives by liquid chromatography/electrospray ionization mass spectrometry: multiplexed detection of negative ion adducts.

    Science.gov (United States)

    Mathis, John A; McCord, Bruce R

    2005-01-01

    The negative ion electrospray ionization mass spectrometric (ESI-MS) detection of adducts of high explosives with chloride, formate, acetate, and nitrate was used to demonstrate the gas-phase interaction of neutral explosives with these anions. The relative intensities of the adduct species were determined to compare the competitive formation of the selected high explosives and anions. The relative stability of the adduct species varies, yielding preferential formation of certain anionic adducts with different high explosives. To exploit this effect, an isocratic high-performance liquid chromatography (HPLC)/ESI-MS method was developed and used for the simultaneous analysis of high explosives using two different techniques for the addition of the anionic additives; pre- and post-column. The results show that the pre-column approach provides similar results with improved selectivity for specific explosives. By detecting characteristic adduct species for each explosive, this method provides a qualitative and quantitative approach for the analysis and identification of high explosives.

  14. Trace determination of 13 haloacetamides in drinking water using liquid chromatography triple quadrupole mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Krasner, Stuart W; Templeton, Michael R

    2012-04-27

    The haloacetamides (HAcAms) are disinfection by-products (DBPs) in drinking water which are currently receiving increased scientific attention due to their elevated toxicity relative to regulated disinfection by-products. A simultaneous determination method of 13 HAcAms, combining solid-phase extraction (SPE) enrichment, liquid chromatographic (LC) separation, and triple quadrupole mass spectrometry (tqMS) detection with atmospheric pressure chemical ionization (APCI) using selective reaction monitoring in positive mode, was developed to measure HAcAms, including chlorinated, brominated, and iodinated analogs. Ammonium chloride and Oasis HLB were selected as the dechlorinating reagent and polymeric SPE sorbent of HAcAm samples. The used tqMS apparatus showed higher sensitivity for the studied HAcAms in the APCI mode than electrospray ionization. 13 HAcAms were separated by LC in 9.0 min, and the detection limits ranged from 7.6 to 19.7 ng/L. The SPE-LC/tqMS method was successfully applied to quantify 13 HAcAms in drinking water samples for the first time, and first indentified tribromoacetamide and chloroiodoacetamide as DBPs in drinking water.

  15. Targeted comparative proteomics by liquid chromatography/matrix-assisted laser desorption/ionization triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Melanson, Jeremy E; Chisholm, Kenneth A; Pinto, Devanand M

    2006-01-01

    Here we report the first application of a matrix-assisted laser desorption/ionization (MALDI) triple-quadrupole mass spectrometer for targeted proteomics. Employing an amine-specific isotopic labelling approach, the technique was validated using five randomly selected bovine serum albumin peptides differentially labelled at known ratios. An indirect benefit of the isotopic labelling technique is a significant enhancement of the a1 ion in tandem mass (MS/MS) spectra of all peptides studied. Therefore, the a1 ion was selected as the fragment ion for multiple reaction monitoring (MRM) in all cases, eliminating tedious method development and optimization. Accurate quantification was achieved with an average relative standard deviation (RSD) of 5% (n = 5) and a detection limit of 14 amol. The technique was then applied to validate an important virulence biomarker of the fungal pathogen Candida albicans, which was not accurately quantified using global proteomics experiment employing two-dimensional liquid chromatography/electrospray ionization tandem mass spectrometry (2D-LC/ESI)-MS/MS. Using LC/MALDI-MRM analysis of five tryptic peptides, the protein PHR1 was found to be upregulated in the hyphal (pathogenic) form of C. albicans by a factor of 7.7 +/- 0.8.

  16. Retention models for ionizable compounds in reversed-phase liquid chromatography: effect of variation of mobile phase composition and temperature.

    Science.gov (United States)

    Rosés, Martí; Subirats, Xavier; Bosch, Elisabeth

    2009-03-06

    General models in reversed-phase liquid chromatography that have been extended to relate retention of ionizable compounds to mobile phase composition, pH and/or temperature are reviewed. In particular, the fundamentals and applications of the solvation parameter model, the polarity parameter model and several classical models based on empirical equations are presented and compared. A main parameter in all these models is the degree of ionization of the acid-base compound, which depends on both the pH of the mobile phase and the acid-base constant of the compound. Thus, on one hand, the different procedures for pH measurement in the mobile phase and their influence on the performance of the models are outlined. On the other hand, equations that relate the variation of the pH of the buffer and the pK(a) of the compound with the mobile phase composition and/or temperature are reviewed and their applicability to the retention models critically discussed.

  17. Matrix-assisted laser desorption/ionization mass spectrometric analysis of aliphatic biodegradable photoluminescent polymers using new ionic liquid matrices.

    Science.gov (United States)

    Serrano, Carlos A; Zhang, Yi; Yang, Jian; Schug, Kevin A

    2011-05-15

    In this study, two novel ionic liquid matrices (ILMs), N,N-diisopropylethylammonium 3-oxocoumarate and N,N-diisopropylethylammonium dihydroxymonooxoacetophenoate, were tested for the structural elucidation of recently developed aliphatic biodegradable polymers by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The polymers, formed by a condensation reaction of three components, citric acid, octane diol, and an amino acid, are fluorescent, but the exact mechanism behind their luminescent properties has not been fully elucidated. In the original studies, which introduced the polymer class (J. Yang et al., Proc. Natl. Acad. Sci. USA 2009, 106, 10086-10091), a hyper-conjugated cyclic structure was proposed as the source for the photoluminescent behavior. With the use of the two new ILMs, we present evidence that supports the presence of the proposed cyclization product. In addition, the new ILMs, when compared with a previously established ILM, N,N-diisopropylethylammonium α-cyano-3-hydroxycinnimate, provided similar signal intensities and maintained similar spectral profiles. This research also established that the new ILMs provided good spot-to-spot reproducibility and high ionization efficiency compared with corresponding crystalline matrix preparations. Many polymer features revealed through the use of the ILMs could not be observed with crystalline matrices. Ultimately, the new ILMs highlighted the composition of the synthetic polymers, as well as the loss of water that was expected for the formation of the proposed cyclic structure on the polymer backbone.

  18. Direct Dark Matter Search with the XENON100 Experiment

    Science.gov (United States)

    Mei, Yuan

    Dark matter, a non-luminous, non-baryonic matter, is thought to constitute 23 % of the matter-energy components in the universe today. Except for its gravitational effects, the existence of dark matter has never been confirmed by any other means and its nature remains unknown. If a hypothetical Weakly Interacting Massive Particle (WIMP) were in thermal equilibrium in the early universe, it could have a relic abundance close to that of dark matter today, which provides a promising particle candidate of dark matter. Minimal Super-Symmetric extensions to the standard model predicts a stable particle with mass in the range 10 GeV/c2 to 1000 GeV/c2, and spin-independent cross-section with ordinary matter nucleon sigmax power of liquid xenon, as well as a 99 kg liquid xenon active veto, the electromagnetic radiation background is greatly suppressed. By utilizing the difference of (S2/S1) between electronic recoil and nuclear recoil, the expected WIMP signature, a small nuclear recoil energy deposition, could be discriminated from electronic recoil background with high efficiency. XENON100 achieved the lowest background rate (< 2.2 x 10--2 events/kg/day/keV) in the dark matter search region (< 40 keV) among all direct dark matter detectors. With 11.2 days of data, XENON100 already sets the world's best spin-independent WIMP-nucleon cross-section limit of 2.7 x 10--44 cm2 at WIMP mass 50 GeV/c 2. With 100.9 days of data, XENON100 excludes WIMP-nucleon cross-section above 7.0 x 10--45 cm2 for a WIMP mass of 50 GeV/c2 at 90% confidence level.

  19. An analysis of LUX data in the ionization-only mode

    Science.gov (United States)

    Uvarov, Sergey; LUX Collaboration Collaboration

    2016-03-01

    The LUX dark matter search experiment is a 350 kg two-phase liquid/gas xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. The ionization-only analysis, which relies on detecting the liberated electrons that escape recombination and drift to the liquid surface, allows us to significantly reduce the energy threshold compared to a standard analysis, thus enabling us to probe lower masses of dark matter candidates. However, this analysis comes at the cost of background rejection power because the primary scintillation signal is often too feeble to be detected at such low energy. Despite this loss of rejection power, the ionization-only analysis features a drastically improved sensitivity to low-mass WIMPs as a result of its very low energy threshold.

  20. Study on LXe system for particle detector (2). Boiling heat transfer characteristics of LXe; Ryushi kenshutsu yo ekitai Xenon shisutemu no kenkyu (2). Ekitai Xenon no futto netsudentatsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Haruyama, T. [High Energy Accelerator Research Organization, Tsukuba (Japan)

    2000-05-29

    In the experiments using a large quantity of liquid xenon as caloric meter, in order to catch the scintillation light generated by collision of the injected high-energy particles with the liquid Xenon, a plurality of photomultiplier cells is arranged in the liquid. At this time, density variation of the liquid is caused as the chip resistance for signal processing generates heat in the liquid Xenon, and makes influence on the scintillation light. Therefore, the basic data concerning heat transfer characteristics such as convection and boiling of the liquid Xenon are necessary. In this study, the heat transfer characteristics of the liquid Xenon is investigated using a Xenon liquefier including a pulse tube-refrigerating machine. Platinum fine wire horizontally placed and a copper round plate are used as a heating element. The system for the experiment is an installation of installing the small pulse tube refrigerating machine for 80K to a glass Dewar. Experimental values of natural convection region and the nucleate boiling region agree comparatively well with the calculation results according to empirical formula. (NEDO)

  1. Ceria nanocubic-ultrasonication assisted dispersive liquid-liquid microextraction coupled with matrix assisted laser desorption/ionization mass spectrometry for pathogenic bacteria analysis.

    Science.gov (United States)

    Abdelhamid, Hani Nasser; Bhaisare, Mukesh L; Wu, Hui-Fen

    2014-03-01

    A new ceria (CeO2) nanocubic modified surfactant is used as the basis of a novel nano-based microextraction technique for highly sensitive detection of pathogenic bacteria (Pseudomonas aeruginosa and Staphylococcus aureus). The technique uses ultrasound enhanced surfactant-assisted dispersive liquid-liquid microextraction (UESA-DLLME) with and without ceria (CeO2) followed by matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). In order to achieve high separation efficiency, we investigated the influential parameters, including extraction time of ultrasonication, type and volume of the extraction solvent and surfactant. Among various surfactants, the cationic surfactants can selectively offer better extraction efficiency on bacteria analysis than that of the anionic surfactants due to the negative charges of bacteria cell membranes. Extractions of the bacteria lysate from aqueous samples via UESA-DLLME-MALDI-MS were successfully achieved by using cetyltrimethyl ammonium bromide (CTAB, 10.0 µL, 1.0×10(-3) M) as surfactants in chlorobenzene (10.0 µL) and chloroform (10.0 µL) as the optimal extracting solvent for P. aeruginosa and S. aureus, respectively. Ceria nanocubic was synthesized, and functionalized with CTAB (CeO2@CTAB) and then characterized using transmission electron microscopy (TEM) and optical spectroscopy (UV and FTIR). CeO2@CTAB demonstrates high extraction efficiency, improve peaks ionization, and enhance resolution. The prime reasons for these improvements are due to the large surface area of nanoparticles, and its absorption that coincides with the wavelength of MALDI laser (337 nm, N2 laser). CeO2@CTAB-based microextraction offers lowest detectable concentrations tenfold lower than that of without nanoceria. The present approach has been successfully applied to detect pathogenic bacteria at low concentrations of 10(4)-10(5) cfu/mL (without ceria) and at 10(3)-10(4) cfu/mL (with ceria) from bacteria suspensions. Finally, the

  2. Comparison of air-agitated liquid-liquid microextraction technique and conventional dispersive liquid-liquid micro-extraction for determination of triazole pesticides in aqueous samples by gas chromatography with flame ionization detection.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Mogaddam, Mohammad Reza Afshar; Aghdam, Abdollah Abdollahi

    2013-07-26

    Two micro-extraction methods, air-agitated liquid-liquid microextraction (AALLME) and dispersive liquid-liquid microextraction (DLLME), have been compared with each other by applying them for the analysis of five triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole and triticonazole) in aqueous samples by gas chromatography with flame ionization detection (GC-FID). In the AALLME method, which excludes any disperser solvent, much less volume of organic solvent is used. In order to form fine and dispersed organic droplets in the aqueous phase, the mixture of aqueous sample solution and extraction solvent is repeatedly aspirated and dispensed with a syringe. In the DLLME method, an appropriate mixture of extraction solvent and disperser solvent is rapidly injected by a syringe into the aqueous sample. Effect of the pertinent experimental factors on DLLME (i.e. identity and volume of the extraction and disperser solvents and ionic strength) and on AALLME (identity and volume of the extraction solvent, number of agitations, and ionic strength) were investigated. Under optimal conditions, limits of detection for the five target pesticides obtained by AALLME-GC-FID and DLLME-GC-FID ranged from 0.20 to 1.1ngmL(-1) and 1.9 to 5.9ngmL(-1), respectively. The relative standard deviations (RSDs, n=5) were in the range of 1-4% and 3-5% with the enrichment factors of 449-504 and 79-143 for AALLME-GC-FID and DLLME-GC-FID, respectively. Both of the compared methods are simple, fast, efficient, inexpensive and can be applied to the analysis of the five pesticides in different aqueous samples in which penconazole and hexaconazole were found. For spiked samples, the recoveries were in the ranges of 92-105%, and 92-104% for AALLME and DLLME, respectively.

  3. Identification of glyceollin metabolites derived from conjugation with glutathione and glucuronic acid in rats by on-line liquid chromatography-electrospray ionization tandem mass spectrometry

    Science.gov (United States)

    Glyceollin-related metabolites produced in rats following oral glyceollin administration were screened and identified by precursor and product ion scanning using liquid chromatography, coupled on-line with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), to identify all glyceollin me...

  4. Specific determination of 20 primary aromatic amines in aqueous food simulants by liquid chromatography-electrospray ionization-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Mortensen, Sarah Kelly; Trier, Xenia Thorsager; Foverskov, Annie

    2005-01-01

    A multi-analyte method without any pre-treatment steps using reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed and applied for the determination of 20 primary aromatic amines (PAA) associated with polyurethane (PUR) products or azo...

  5. Development of a transient response technique for heterogeneous catalysis in the liquid phase, Part 1: Applying an electrospray ionization mass spectrometry (ESI-MS) detector.

    NARCIS (Netherlands)

    Radivojevic, D.; Ruitenbeek, M.; Seshan, Kulathuiyer; Lefferts, Leonardus

    2008-01-01

    We have developed a novel, transient response technique for liquid-phase heterogeneous catalytic studies, equipped with an electrospray ionization mass spectrometry (ESI-MS) detector. The technique was successfully applied as an online method for real-time detection of species dissolved in aqueous

  6. Viscoelasticity of Xenon near the Critical Point

    Science.gov (United States)

    Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.

    1999-01-01

    Using a novel, overdamped, oscillator flown aboard the Space Shuttle, we measured the viscosity of xenon near the liquid-vapor critical point in the frequency range 2 Hz less than or equal to f less than or equal to 12 Hz. The measured viscosity divergence is characterized by the exponent z(sub eta) = 0.0690 +/- 0.0006, in agreement with the value z(sub eta) = 0.067 +/- 0.002 calculated from a two-loop perturbation expansion. Viscoelastic behavior was evident when t = (T - T(sub c))/T(sub c) less than 10(exp -5) and dominant when t less than 10(exp -6), further from T(sub c) than predicted. Viscoelastic behavior scales as Af(tau) where tau is the fluctuation decay time. The measured value of A is 2.0 +/- 0.3 times the result of a one-loop calculation. (Uncertainties stated are one standard uncertainty.)

  7. Determination of tamsulosin in human aqueous humor and serum by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Keski-Rahkonen, Pekka; Pärssinen, Olavi; Leppänen, Esa; Mauriala, Timo; Lehtonen, Marko; Auriola, Seppo

    2007-01-17

    A simple, sensitive and selective LC-MS/MS method was developed for the determination of tamsulosin in human aqueous humor and serum to study the recently reported eye-related adverse effects of this alpha(1)-blocker drug. Aqueous humor samples were analyzed by direct injection, after addition of the internal standard, labetalol. Liquid-liquid extraction with ethyl acetate was used for serum sample preparation. The chromatographic separation was performed on a reversed phase column by gradient elution with acetonitrile -0.1% formic acid at a flow-rate of 0.2 ml/min. Detection and quantification of the analytes were carried out with a linear ion trap mass spectrometer, using positive electrospray ionization (ESI) and multiple reaction monitoring (MRM). The limit of quantification was 0.1 ng/ml for both aqueous humor and serum samples and linearity was obtained over the concentration ranges of 0.1-4.7 ng/ml and 0.1-19.3 ng/ml for aqueous humor and serum samples, respectively. Acceptable accuracy and precision were obtained for concentrations within the standard curve ranges. The method has been used for the determination of tamsulosin in aqueous humor and serum samples from patients that were on tamsulosin medication and underwent cataract surgery.

  8. SPE coupled with dispersive liquid-liquid microextraction followed by GC with flame ionization detection for the determination of ultra-trace amounts of benzodiazepines.

    Science.gov (United States)

    Ghobadi, Masoomeh; Yamini, Yadollah; Ebrahimpour, Behnam

    2014-02-01

    SPE combined with dispersive liquid-liquid microextration was used for the extraction of ultra-trace amounts of benzodiazepines (BZPs) including, diazepam, midazolam, and alprazolam, from ultra-pure water, tap water, fruit juices, and urine samples. The analytes were adsorbed from large volume samples (60 mL) onto octadecyl silica SPE columns. After the elution of the desired compounds from sorbents with 2.0 mL acetone, 0.5 mL of eluent containing 40.0 μL chloroform was injected rapidly into 4.5 mL pure water. After extraction and centrifugation, 2 μL of the sedimented phase was injected into a GC equipped with a flame ionization detector. Several parameters affecting this process were investigated and optimized. Under the optimal conditions, LODs ranged from 0.02 to 0.05 μg/L, a linear dynamic range of 0.1-100 μg/L and relative SDs in the range of 4.4-10.7% were attained. Very high preconcentration factors ranging from 3895-7222 were achieved. The applicability of the method for the extraction of BZPs from different types of complicated matrices, such as tap water, fruit juices, and urine samples, was studied. The obtained results reveal that the proposed method is a good technique for the extraction and determination of BZPs in complex matrices.

  9. Determination of strychnine and brucine in rat plasma using liquid chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Xu, Yanyan; Si, Duanyun; Liu, Changxiao

    2009-02-20

    A simple, sensitive and selective liquid chromatography-electrospray mass spectrometric (LC-ESI-MS) method was developed and validated for simultaneous determination of strychnine and brucine in rat plasma, using tacrine as the internal standard (IS). Sample preparation involved a liquid-liquid extraction of the analytes with n-hexane, dichloromethane and isopropanol (65:30:5, v/v/v) from 0.1mL of plasma. Chromatographic separation was carried out on a Waters C(18) column using a mobile phase of methanol-20mM ammonium formate-formic acid (32:68:0.68, v/v/v). Positive selected ion monitoring mode was used for detection of strychnine, brucine and the IS at m/z 335.2, m/z 395.2 and m/z 199.2, respectively. Linearity was obtained over the concentration range of 0.5-500ng/mL for strychnine and 0.1-100ng/mL for brucine. The lower limit of quantification was 0.5ng/mL and 0.1ng/mL for strychnine and brucine, respectively. The intra- and inter-day precision for both strychnine and brucine was less than 7.74%, and accuracy ranged from -4.38% to 2.21% at all QC levels. The method has been successfully applied to a pharmacokinetic study of processed Semen Strychni after oral administration to rats.

  10. Experimental analysis of general ion recombination in a liquid-filled ionization chamber in high-energy photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eunah; Seuntjens, Jan [Medical Physics Unit, McGill University, Montreal General Hospital (L5-113), 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada); Davis, Stephen [Department of Medical Physics, McGill University Health Centre, Montreal General Hospital (L5-112), 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada)

    2013-06-15

    Purpose: To study experimentally the general ion recombination effect in a liquid-filled ionization chamber (LIC) in high-energy photon beams. Methods: The general ion recombination effect on the response of a micro liquid ion chamber (microLion) was investigated with a 6 MV photon beam in normal and SRS modes produced from a Varian{sup Registered-Sign} Novalis Tx{sup TM} linear accelerator. Dose rates of the linear accelerator were set to 100, 400, and 1000 MU/min, which correspond to pulse repetition frequencies of 60, 240, and 600 Hz, respectively. Polarization voltages applied to the microLion were +800 and +400 V. The relative collection efficiency of the microLion response as a function of dose per pulse was experimentally measured with changing polarization voltage and pulse repetition frequencies and was compared with the theoretically calculated value. Results: For the 60 Hz pulse repetition frequency, the experimental relative collection efficiency was not different from the theoretical one for a pulsed beam more than 0.3% for both polarization voltages. For a pulsed radiation beam with a higher pulse repetition frequency, the experimental relative collection efficiency converged to the theoretically calculated efficiency for continuous beams. This result indicates that the response of the microLion tends toward the response to a continuous beam with increasing pulse repetition frequency of a pulsed beam because of low ion mobility in the liquid. Conclusions: This work suggests an empirical method to correct for differences in general ion recombination of a LIC between different radiation fields. More work is needed to quantitatively explain the LIC general ion recombination behavior in pulsed beams generated from linear accelerators.

  11. Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aprile, E.; Contreras, H.; Goetzke, L.W.; Fernandez, A.J.M.; Messina, M.; Plante, G.; Rizzo, A. [Columbia University, Physics Department, New York, NY (United States); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Bologna Univ., Department of Physics and Astrophysics, Bologna (Italy); INFN, Bologna (Italy); Alfonsi, M. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Arazi, L.; Budnik, R.; Duchovni, E.; Gross, E.; Itay, R.; Landsman, H.; Lellouch, D.; Levinson, L.; Priel, N.; Vitells, O. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); Arisaka, K.; Lyashenko, A.; Meng, Y.; Pantic, E.; Teymourian, A.; Wang, H. [University of California, Physics and Astronomy Department, Los Angeles, CA (United States); Arneodo, F.; Di Giovanni, A. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Auger, M.; Barrow, P.; Baudis, L.; Behrens, A.; Galloway, M.; Kessler, G.; Kish, A.; Mayani, D.; Pakarha, P.; Piastra, F. [University of Zurich, Physik-Institut, Zurich (Switzerland); Balan, C.; Cardoso, J.M.R.; Lopes, J.A.M.; Santos, J.M.F. dos [University of Coimbra, Department of Physics, Coimbra (Portugal); Bauermeister, B.; Fattori, S.; Geis, C.; Grignon, C.; Oberlack, U.; Schindler, S. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik and Exzellenzcluster PRISMA, Mainz (Germany); Beltrame, P. [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel); University of Edinburgh, Edinburgh (United Kingdom); Brown, A.; Lang, R.F.; Macmullin, S.; Pienaar, J.; Reichard, S.; Reuter, C. [Purdue University, Department of Physics and Astronomy, West Lafayette, IN (United States); Brown, E.; Levy, C. [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy, Troy, NY (United States); Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Bruenner, S.; Hampel, W.; Kaether, F.; Lindemann, S.; Lindner, M.; Undagoitia, T.M.; Rauch, L.; Schreiner, J.; Simgen, H.; Weber, M. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bruno, G. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Buetikofer, L.; Coderre, D.; Schumann, M. [University of Bern, Albert Einstein Center for Fundamental Physics, Bern (Switzerland); Colijn, A.P.; Decowski, M.P.; Tiseni, A.; Tunnell, C. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); Cussonneau, J.P.; Le Calloch, M.; Masbou, J.; Lavina, L.S.; Thers, D. [Universite de Nantes, Subatech, Ecole des Mines de Nantes, CNRS/In2p3, Nantes (France); Ferella, A.D.; Fulgione, W.; Laubenstein, M. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); Fieguth, A.; Murra, M.; Rosendahl, S.; Weinheimer, C. [Wilhelms-Universitaet Muenster, Institut fuer Kernphysik, Muenster (Germany); Garbini, M.; Massoli, F.V.; Sartorelli, G.; Selvi, M. [Bologna Univ., Department of Physics and Astrophysics, Bologna (Italy); INFN, Bologna (Italy); Miguez, B.; Molinario, A.; Trinchero, G. [INFN-Torino and Osservatorio Astrofisico di Torino, Turin (Italy); Naganoma, J.; Shagin, P.; Wall, R. [Rice University, Department of Physics and Astronomy, Houston, TX (United States); Orrigo, S.E.A. [University of Coimbra, Department of Physics, Coimbra (Portugal); IFIC, CSIC-Universidad de Valencia, Valencia (Spain); Persiani, R. [Universite de Nantes, Subatech, Ecole des Mines de Nantes, CNRS/In2p3, Nantes (FR); Bologna Univ., Department of Physics and Astrophysics, Bologna (IT); INFN, Bologna (IT); Collaboration: XENON Collaboration

    2015-11-15

    The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, we detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment. (orig.)

  12. Lowering the radioactivity of the photomultiplier tubes for the XENON1T dark matter experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aprile, E. [Physics Department, Columbia University, New York, NY (United States); Agostini, F. [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L’Aquila (Italy); Department of Physics and Astrophysics, University of Bologna and INFN-Bologna, Bologna (Italy); Alfonsi, M. [Nikhef and the University of Amsterdam, Science Park, Amsterdam (Netherlands); Institut für Physik & Exzellenzcluster PRISMA, Johannes Gutenberg-Universität Mainz, Mainz (Germany); Arazi, L. [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot (Israel); Collaboration: XENON Collaboration; and others

    2015-11-23

    The low-background, VUV-sensitive 3-inch diameter photomultiplier tube R11410 has been developed by Hamamatsu for dark matter direct detection experiments using liquid xenon as the target material. We present the results from the joint effort between the XENON collaboration and the Hamamatsu company to produce a highly radio-pure photosensor (version R11410-21) for the XENON1T dark matter experiment. After introducing the photosensor and its components, we show the methods and results of the radioactive contamination measurements of the individual materials employed in the photomultiplier production. We then discuss the adopted strategies to reduce the radioactivity of the various PMT versions. Finally, we detail the results from screening 286 tubes with ultra-low background germanium detectors, as well as their implications for the expected electronic and nuclear recoil background of the XENON1T experiment.

  13. Liquid Chromatography-Electrospray Ionization Mass Spectrometry Method for Determination of Protopanaxadiol in Rat Plasma

    Institute of Scientific and Technical Information of China (English)

    WU Yi; TENG Guo-sheng; LIANG Yong-tao; ZHONG Da-fang; LIU Bing

    2009-01-01

    A simple, rapid and sensitive method for the determination of protopanaxadiol in rat plasma with ginse-noside Rh2 as internal standard was developed and validated. The analyte and internal standard were extracted from plasma with ether-dichloromethane(3:2, volume ratio) and then were analyzed by reversed-phase HPLC on a short Zorbax Extend C_(18) column(50 mm×2.1 mm, 3.5 μm i.d.) eluted with a mobile phase consisting of acetoni-trile/methanol 0.10 mmol/L ammonium acetate(45:45:10, volume ratio) at 0.4 mL/min. Detection was performed on an Applied Biosystems Sciex API 4000 mass spectrometer set at unit resolution in the multiple reaction monitoring mode. Electrospray ionization was used for ion production. The assay method shows linear over a range of 5-2000 ng/mL and intra- and inter-day precisions over this range were <10.0% with accuracy ranged from 86.3% to 114.1%. The limit of detection was 500 pg/mL in the plasma. The method was successfully applied to a preclinical pharmaco-kinetic study of protopanaxadiol(17.5 mg/kg) administered as a single oral dose.

  14. Dose verifications by use of liquid ionization chamber of an electronic portal imaging device (EPID).

    Science.gov (United States)

    Tateoka, Kunihiko; Oouchi, Atsushi; Nakata, Kensei; Hareyama, Masato

    2008-07-01

    In this study, we examined the ability of an L-EPID to verify rectangular and irregular fields and to measure the transmitted exit doses. With respect to the beam profile of rectangular and irregular fields and the doses transmitted through an inhomogeneous phantom, the L-EPID dose obtained from the L-EPID measurement was compared with the conventional dose measured by use of a 0.12-cc ionization chamber and a 3D water phantom. In the comparison of the rectangular and irregular fields, the difference in the off-center ratio (OCR) between the L-EPID dose and the conventional dose was approximately 3% in the steep-dose-gradient region (penumbra regions, >30%/cm) and approximately +/-0.5% in the gentle-dose-gradient region (5%/cm). On the other hand, the dose differences between the L-EPID and the measured doses were less than approximately 2% in the gentle-dose-gradient region. In addition, in the steep-dose-gradient region, the maximum difference was 30%. However, the differences in the distance-to-agreement (DTA) were less than approximately +/-1 mm and were unrelated to the dose gradient. These results suggest that dose verification by L-EPID is very useful in clinical applications.

  15. STRUCTURAL DETERMINATION AND QUANTITATIVE ANALYSIS OF BACTERIAL PHOSPHOLIPIDS USING LIQUID CHROMATOGRAPHY/ELECTROSPRAY IONIZATION/MASS SPECTROMETRY

    Science.gov (United States)

    This report presents a comprehensive spectral analysis of common bacterial phospholipids using electrospray/mass spectrometry (ESI/MS) under both negative and positive ionization conditions. Phospholipids under positive ionization yield sodium-adduct molecular ions which are mos...

  16. Study of Hydrophobic and Ionizable Hydrophilic Copolymers at Polymer/Solid and Polymer/Liquid Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Perahia, Dvora

    2011-11-01

    Joint experimental-computational efforts were set to characterize the interfacial effects on the structure and dynamics of polymers consisting of highly rigid hydrophilic-ionizable and hydrophobic sub-units within one polymeric chain casted into thin films of several molecular dimensions. Focusing on the ultra thin film region we separate out the interfacial effects from bulk characteristics. Specifically, the study sought to: identify the parameters that control the formation of a stable polymer-solid interface. The study consists of two components, experimental investigations and computational efforts. The experimental component was designed to derive empirical trends that can be used to correlate the set of coupled polymer molecular parameters with the interfacial characteristics of these polymers, and their response to presence of solvents. The computational study was designed to provide molecular insight into the ensemble averages provided by the experimental efforts on multiple length scales from molecular dimensions, to the nanometer lengths to a macroscopic understanding of solvent interactions with structured polymers. With the ultimate goal of correlating molecular parameters to structure, dynamics and properties of ionic polymers, the first stage of the research began with the study of two systems, one which allowed tailoring the flexibility of the backbone without the presence of ionic groups, but with a potential to sulfonate groups at a later stage, and a polymer whose backbone is rigid and the density of the ionic group can be varied. The combined experimental and computational studies significantly extended the understanding of polymers at interfaces from model systems to polydispersed copolymers with blocks of varying nature and complexity. This new insight directly affects the design of polymers for sustainable energy applications from batteries and fuel cells to solar energy.

  17. Ionization in liquids. Progress report, September 1, 1977-April 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Bakale, G.

    1980-12-19

    Quasifree electrons simulate the behavior of unsolvated or dry electrons in aqueous media including the special case of biological systems. A model of direct radiosensitization was developed based on dry charge-carriers having an extended lifetime in the sheath of structured water that surrounds polar biomolecules. In this model, the pre-solvation lifetimes of dry electrons increased with an increase in the rotational times of solvent molecules. During the development of this model, an increasing number of radiosensitizers were found to be carcinogenic. Measurement of the k/sub e/'s of known carcinogens and noncarcinogens revealed that carcinogens attached quasifree electrons at diffusion-controlled rates, whereas the k/sub e/'s of noncarcinogens were significantly less. To explore the k/sub e/-carcinogenicity correlation further, a study of quasifree electron attachment to the water pools of reversed micelles was conducted. The degree of structuredness of the water pools which determines the k/sub e/ of the reversed micellar systems was also controlled. Another approach to controlling the microenvironment of quasifree electrons in biological systems was done in studies of radiation-induced damage to DNA in concentrated DNA solutions. The high concentration of DNA introduces more structure into the solutions than that occurring in typical in vitro experiments. The structural enhancement by DNA extends the lifetime of unsolvated charge-carriers. The DNA-damaging effects of radiolyticaly produced charge-carriers were also determined in studies of synergistic mutagenesis in bacteria simultaneously exposed to ionizing radiation and electrophilic chemical carcinogens. The attachment-detachment equilibrium of nicotine in hexane solutions was also studied. Both the kinetics and the thermodynamics of electron reactions were studied. (ERB)

  18. An apparatus to manipulate and identify individual Ba ions from bulk liquid Xe.

    Science.gov (United States)

    Twelker, K; Kravitz, S; Montero Díez, M; Gratta, G; Fairbank, W; Albert, J B; Auty, D J; Barbeau, P S; Beck, D; Benitez-Medina, C; Breidenbach, M; Brunner, T; Cao, G F; Chambers, C; Cleveland, B; Coon, M; Craycraft, A; Daniels, T; Daugherty, S J; Davis, C G; DeVoe, R; Delaquis, S; Didberidze, T; Dilling, J; Dolinski, M J; Dunford, M; Fabris, L; Farine, J; Feldmeier, W; Fierlinger, P; Fudenberg, D; Giroux, G; Gornea, R; Graham, K; Hall, C; Heffner, M; Herrin, S; Hughes, M; Jiang, X S; Johnson, T N; Johnston, S; Karelin, A; Kaufman, L J; Killick, R; Koffas, T; Krücken, R; Kuchenkov, A; Kumar, K S; Leonard, D S; Leonard, F; Licciardi, C; Lin, Y H; MacLellan, R; Marino, M G; Mong, B; Moore, D; Odian, A; Ostrovskiy, I; Ouellet, C; Piepke, A; Pocar, A; Retiere, F; Rowson, P C; Rozo, M P; Schubert, A; Sinclair, D; Smith, E; Stekhanov, V; Tarka, M; Tolba, T; Tosi, D; Vuilleumier, J-L; Walton, J; Walton, T; Weber, M; Wen, L J; Wichoski, U; Yang, L; Yen, Y-R; Zhao, Y B

    2014-09-01

    We describe a system to transport and identify barium ions produced in liquid xenon, as part of R&D towards the second phase of a double beta decay experiment, nEXO. The goal is to identify the Ba ion resulting from an extremely rare nuclear decay of the isotope (136)Xe, hence providing a confirmation of the occurrence of the decay. This is achieved through Resonance Ionization Spectroscopy (RIS). In the test setup described here, Ba ions can be produced in liquid xenon or vacuum and collected on a clean substrate. This substrate is then removed to an analysis chamber under vacuum, where laser-induced thermal desorption and RIS are used with time-of-flight mass spectroscopy for positive identification of the barium decay product.

  19. Xenon preconditioning: molecular mechanisms and biological effects

    Directory of Open Access Journals (Sweden)

    Liu Wenwu

    2013-01-01

    Full Text Available Abstract Xenon is one of noble gases and has been recognized as an anesthetic for more than 50 years. Xenon possesses many of the characteristics of an ideal anesthetic, but it is not widely applied in clinical practice mainly because of its high cost. In recent years, numerous studies have demonstrated that xenon as an anesthetic can exert neuroprotective and cardioprotective effects in different models. Moreover, xenon has been applied in the preconditioning, and the neuroprotective and cardioprotective effects of xenon preconditioning have been investigated in a lot of studies in which some mechanisms related to these protections are proposed. In this review, we summarized these mechanisms and the biological effects of xenon preconditioning.

  20. Study on LXe system for particle detector. Liquefaction test by pulse tube refrigerator; Ryushi kenshutsuyo ekitai Xenon shisutemu no kenkyu. Parusu kan reitokini yoru ekika

    Energy Technology Data Exchange (ETDEWEB)

    Haruyama, T.; Kasami, K. [High energy Accelerator Research Organization, Tsukuba (Japan)

    1999-11-10

    It is supersensitively used for the particle detection from electrons and that they release the light, that it can deal with fast process, etc. for the high-energy particle which emits liquid Xenon. It recently proposes the experiment which uses large liquid Xenon as a calorimeter in order to detect {gamma}ray of the high energy. It examines the thermal characteristic of liquid Xenon, while this study attempts the optimization in liquefying Xenon by pulse tube refrigerating machine. This time, the following are reported: Introduction of the Xenon gas system for the small-scale liquefaction experiment and experiment near 165K of small pulse tube refrigerating machine on a refrigerating capacity. (NEDO)

  1. First Dark Matter Results from the XENON100 Experiment

    CERN Document Server

    Aprile, E; Arneodo, F; Askin, A; Baudis, L; Behrens, A; Brown, E; Cardoso, J M R; Choi, B; Cline, D B; Fattori, S; Ferella, A D; Giboni, K -L; Hugenberg, K; Kish, A; Lam, C W; Lamblin, J; Lang, R F; Lim, K E; Lopes, J A M; Undagoitia, T Marrodán; Mei, Y; Fernandez, A J Melgarejo; Ni, K; Oberlack, U; Orrigo, S E A; Pantic, E; Plante, G; Ribeiro, A C C; Santorelli, R; Santos, J M F dos; Schumann, M; Shagin, P; Teymourian, A; Thers, D; Tziaferi, E; Wang, H; Weinheimer, C

    2010-01-01

    The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon in an ultra-low background dual-phase time projection chamber. In this letter, we present first dark matter results from the analysis of 11.17 live days of non-blind data, acquired in October and November 2009. In the selected fiducial target of 40 kg, and within the pre-defined signal region, we observe no events and hence exclude spin-independent WIMP-nucleon elastic scattering cross-sections above 3 x 10^-44 cm^2 for 50 GeV/c^2 WIMPs at 90% confidence level. Below 20 GeV/c^2, this result challenges the interpretation of the CoGeNT or DAMA signals as being due to spin-independent, elastic, light mass WIMP interactions.

  2. NEXT: R and D towards a xenon high pressure TPC

    Energy Technology Data Exchange (ETDEWEB)

    Lux, Thorsten [Universitat Autonoma de Barcelona, Barcelona (Spain); Sanchez, Federico [IFAE, Barcelona (Spain); Gomez-Cadenas, J.J.; Martin-Albo, Justo; Ball, Markus; Novella, Pau; Monrabal, Francesc; Cervera, Anselmo [IFIC, Valencia (Spain); Garcia Irastorza, Igor [Universidad de Zaragoza, Zaragoza (Spain)

    2008-07-01

    An open question within the Standard Model is the nature of the neutrino. Is it a Majorana or a Dirac particle? The only way to answer this, is the search for neutrino-less double beta decays. Various experimental approaches are investigated for this reason e.g. diodes, bolometers, liquid Xenon. The key points for all of them is the high requirements on the energy resolution to distinguish between the decay with two neutrinos and the neutrino-less decay and the external background suppression. Recently some Spanish groups started a R and D program to investigate the possibility to use a pressurized Xenon TPC with MPGD readout (MM, LEM (GEM)). In the presentation the choice of gaseous Xe is motivated and an overview about the R and D plans is given.

  3. Quantitative analysis of cytokinins in plants by high performance liquid chromatography: electronspray ionization ion trap mass spectrometry.

    Science.gov (United States)

    Chen, Weiqi; Gai, Ying; Liu, Shichang; Wang, Renxiao; Jiang, Xiangning

    2010-10-01

    The present paper introduces a highly sensitive and selective method for simultaneous quantification of 12 cytokinins (free form and their conjugates). The method includes a protocol of extraction with methanol/water/formic acid (15/4/1, v/v/v) to the micro-scale samples, pre-purification with solid phase extraction (SPE) cartridges of the extracts, separation with a high performance liquid chromatography (HPLC) and detection by an electrospray ionization ion trap mass spectrometry (ESI-Ion trap-MS) system in a consecutive ion monitoring (CRM) mode at the three stage fragmentation of mass spectrometry (MS(3) ). The lowest detection level of the cytokinins of the method reaches 0.1-2.0 pg with a very wide range of linear regression from 1-512 pg, at the coefficient factors of 0.98-0.99. The feasibility of this method has been proven in the application of the method to the analysis of the trace-amount contents of cytokinins in the micro-scale samples of various types of plant materials, such as aerial parts of rice and poplar leaves etc. 12 endogenous cytokinins had been identified and quantified in the plant tissues, with an acceptable relatively higher recovery rate from 40% to 70%.

  4. Determination of deltamethrin residues in plant materials by liquid chromatography/tandem mass spectrometry with electrospray ionization.

    Science.gov (United States)

    Zimmer, Dieter; Philipowski, Christiane; Posner, Birgit; Gnielka, Agnes; Dirr, Edgar; Dorff, Mario

    2006-01-01

    This paper describes a selective and sensitive method that uses liquid chromatography/tandem mass spectrometry with positive electrospray ionization (ESI+) for the determination of deltamethrin in a variety of crops. Samples were extracted by conventional high-speed blending. Some samples required no further cleanup; others were cleaned up by gel permeation chromatography, strong cation-exchange cartridges, or partitioning with n-hexane. In the determinative step, the buffered neutral mobile phase, consisting of 10 mM ammonium acetate (pH 6.8) and methanol, and ESI+ provided strong ammonium adduct formation to [M+NH4]+ at m/z 523, and the multiple-reaction monitoring (MRM) transition at m/z 523/281 was used for the quantitation of deltamethrin. A second MRM transition at m/z 525/283 was used for confirmation. The limit of quantitation (LOQ) values were 0.01 mg/kg for edible materials and 0.05 mg/kg for nonedible materials. Mean overall recoveries at the LOQ and the 10-fold LOQ ranged from 73 to 96%, and the relative standard deviations were <10% for all samples materials analyzed.

  5. Quantitative Analysis of Cytokinins in Plants by High Performance Liquid Chromatography: Electronspray Ionization Ion Trap Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Weiqi Chen; Ying Gai; Shichang Liu; Renxiao Wang; Xiangning Jiang

    2010-01-01

    The present paper introduces a highly sensitive and selective method for simultaneous quantification of 12 cytokinins(free form and their conjugates).The method includes a protocol of extraction with methanol/water/formic acid(1514/1,v/v/v)to the micro-scale samples,pre-purification with solid phase extraction(SPE)cartridges of the extracts,separation with a high performance liquid chromatography(HPLC)and detection by an electrospray ionization ion trap mass spectrometry(ESI-Ion trap-MS)system in a consecutive ion monitoring(CRM)mode at the three stage fragmentation of mass spectrometry(MS3).The lowest detection level of the cytokinins of the method reaches 0.1-2.0 pg with a very wide range of linear regression from 1-512 pg,at the coefficient factors of 0.98-0.99.The feasibility of this method has been proven in the application of the method to the analysis of the trace-amount contents of cytokinins in the micro-scale samples of various types of plant materials,such as aerial parts of rice and poplar leaves etc.12 endogenous cytokinins had been identified and quantified in the plant tissues,with an acceptable relatively higher recovery rate from 40% to 70%.

  6. Novel ionic liquid matrices for qualitative and quantitative detection of carbohydrates by matrix assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Zhao, Xiaoyong; Shen, Shanshan; Wu, Datong; Cai, Pengfei; Pan, Yuanjiang

    2017-09-08

    Analysis of carbohydrates based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is still challenging and researchers have been devoting themselves to efficient matrices discovery. In the present study, the design, synthesis, qualitative and quantitative performance of non-derivative ionic liquid matrices (ILMs) were reported. DHB/N-methylaniline (N-MA) and DHB/N-ethylaniline (N-EA), performing best for carbohydrate detection, have been screened out. The limit of detection for oligosaccharide provided by DHB/N-MA and DHB/N-EA were as low as 10 fmol. DHB/N-MA and DHB/N-EA showed significantly higher ion generation efficiency than DHB. The comparison of capacity to probe polysaccharide between these two ILMs and DHB also revealed their powerful potential. Their outstanding performance were probably due to lower proton affinities and stronger UV absorption at λ = 355 nm. What is more, taking DHB/N-MA as an example, quantitative analysis of fructo-oligosaccharide mixtures extracted and identified from rice noodles has been accomplished sensitively using an internal standard method. Overall, DHB/N-MA and DHB/N-EA exhibited excellent performance and might be significant sources as the carbohydrate matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Determination of Isoflavone Content in SRM 3238 Using Liquid Chromatography-Particle Beam/Electron Ionization Mass Spectrometry

    Science.gov (United States)

    Zhang, Lynn X.; Burdette, Carolyn Q.; Phillips, Melissa M.; Rimmer, Catherine A.; Marcus, R. Kenneth

    2016-01-01

    The characterization of marker components in botanical materials is a challenging task and the increased consumption of botanicals and dietary supplements demands a greater understanding of the associated health benefits and risks. In order to successfully acquire and compare clinical results and correlate health trends, accurate, precise, and validated methods of analysis must be developed. Presented here is the development of a quantitative method for the determination of soy isoflavones (daidzin, glycitin, genistin, daidzein, and genistein) using liquid chromatography-particle beam/electron ionization mass spectrometry (LC-PB/EIMS). An internal standard (IS) approach for quantitation using 7-hydroxy-4-chromone as the IS compound was employed, with response factors for each individual isoflavone obtained from calibrant solutions. The results from this method were compared with the certified and reference values for NIST SRM 3238 Soy-Containing Solid Oral Dosage Form to demonstrate that the method was in control. Results obtained using LC-PB/EIMS were consistent with the NIST certified or reference values and their uncertainties for all five isoflavones, demonstrating that the LC-PB/EIMS approach is both accurate and precise when used for the determination of the target isoflavones in soy-containing dietary supplement finished products, while simultaneously providing structural information. PMID:26651559

  8. Pesticide analysis at ppt concentration levels: coupling nano-liquid chromatography with dielectric barrier discharge ionization-mass spectrometry.

    Science.gov (United States)

    Mirabelli, Mario F; Wolf, Jan-Christoph; Zenobi, Renato

    2016-05-01

    We report the coupling of nano-liquid chromatography (nano-LC) with an ambient dielectric barrier discharge ionization (DBDI)-based source. Detection and quantification were carried out by high-resolution mass spectrometry (MS), using an LTQ-Orbitrap in full scan mode. Despite the fact that nano-LC systems are rarely used in food analysis, this coupling was demonstrated to deliver extremely high sensitivity in pesticide analysis, with limits of detection (LODs) as low as 10 pg/mL. In all cases, the limits of quantification (LOQs) were compliant with the current EU regulation. An excellent signal linearity over up to four orders of magnitude was also observed. Therefore, this method can easily compete with conventional GC-(EI)-MS or LC-ESI-MS/MS methods and in some cases outperform them. The method was successfully tested for food sample analysis, with apples and baby food, extracted using the QuEChERS approach. Our results demonstrate an outstanding sensitivity (at femtogram level) and reproducibility of the nano-LC-DBDI coupling, capable of improving routine pesticide analysis. To the best of our knowledge, this is the most sensitive and reproducible plasma-MS-based method for pesticide analysis reported to date.

  9. Quantification of steroidal alkaloids in Buxus papillosa using electrospray ionization liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Musharraf, Syed Ghulam; Goher, Madiha; Zareena, Bibi

    2015-08-01

    Buxus papillosa is one of the most extensively studied species of the genus Buxus known to possess steroidal alkaloids which can be used for assessing the various pharmacological activities of this plant. This paper describes the liquid chromatography-electrospray ionization triple quadrupole mass spectrometry (LC-ESI-QQQ-MS) method for the quantification of six steroidal alkaloids as chemical markers in the extracts of leaves, roots and stems of B. papillosa. Quantitative MS/MS analysis was carried out by optimization of the most sensitive transition for each analyte. This has yielded detection and quantification limits of 0.486-8.08 ng/mL and 1.473-24.268 ng/mL, respectively for all analytes. Linearity of response was also achieved and the regression coefficient found to be >0.99 for all analyzed compounds. The newly developed MRM (Multiple Reaction Monitoring) method showed excellent sensitivity for the quantification of steroidal alkaloids within 15 min run time. This paper describes the application of LC-QQQ-MS technique for steroidal alkaloids analysis in plant samples.

  10. Hydrophilic interaction liquid chromatography-electrospray ionization-tandem mass spectrometry of a complex mixture of native and oxidized phospholipids.

    Science.gov (United States)

    Losito, I; Facchini, L; Diomede, S; Conte, E; Megli, F M; Cataldi, T R I; Palmisano, F

    2015-11-27

    A mixture of native and oxidized phospholipids (PLs), generated by the soybean lipoxygenase type V-catalyzed partial oxidation of a lipid extract obtained from human platelets, was analyzed by Hydrophilic Interaction Liquid Chromatography-ElectroSpray Ionization-Tandem Mass Spectrometry (HILIC-ESI-MS/MS). The complexity of the resulting mixture was remarkable, considering that the starting lipid extract, containing (as demonstrated in a previous study) about 130 native PLs, was enriched with enzymatically generated hydroperoxylated derivatives and chemically generated hydroxylated forms of PLs bearing polyunsaturated side chains. Nonetheless, the described analytical approach proved to be very powerful; indeed, focusing on phosphatidylcolines (PCs), the most abundant PL class in human platelets, about fifty different native/oxidized species could be identified in a single HILIC-ESI-MS/MS run. Low-energy collision induced dissociation tandem MS (CID-MS/MS) experiments on chromatographically separated species showed single neutral losses of H2O2 and H2O to be typical fragmentation pathways of hydroperoxylated PCs, whereas a single H2O loss was observed for hydroxylated ones. Moreover, diagnostic losses of n-hexanal or n-pentanol were exploited to recognize PCs hydroperoxylated on the last but five carbon atom of a ɷ-6 polyunsaturated side chain. Despite the low resolution of the 3D ion trap mass analyzer used, the described HILIC-ESI-MS/MS approach appears very promising for the identification of oxidized lipids in oxidatively stressed complex biological systems.

  11. Fast carbohydrate analysis via liquid chromatography coupled with ultra violet and electrospray ionization ion trap detection in 96-well format.

    Science.gov (United States)

    Rühmann, Broder; Schmid, Jochen; Sieber, Volker

    2014-07-11

    A fast carbohydrate screening platform processible in 96-well format is described. The method is suitable for the determination of various carbohydrates out of complex mixtures as obtained by acidic hydrolysis of carbohydrates polymers. The chromatographic conditions for an efficient separation (12min) and the derivatization process with 1-phenyl-3-methyl-5-pyrazolone (PMP) were optimized for high resolution separation and simultaneous determination of deoxy-, amino-, anhydro-sugars as well as hexoses, pentoses, dimers, uronic acids and degradation products like furfural and hydroxymethylfurfural (HMF). The potential to quantify with UV- and MS-detector in the same range has been demonstrated for 20 different compounds. Finally, the matrix effects of the hydrolysis were positively evaluated. The micro scale hydrolysis and PMP-derivatization without any extraction or drying steps, both in 96-well format, result in a fast and intuitive sample preparation. In combination with a fast liquid chromatography coupled to UV and electrospray ionization ion trap detection (LC-UV-ESI-MS/MS) for the qualification and quantification of various sugars, dimers and degradation products, this method shows great performance in carbohydrate analysis.

  12. Analysis of Genomic DNA Methylation Levels in Human Placenta using Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Sulistyo Emantoko Dwi Putra

    2014-03-01

    Full Text Available Background: DNA-methylation is a common epigenetic tool which plays a crucial role in gene regulation and is essential for cell differentiation and embryonic development. The placenta is an important organ where gene activity can be regulated by epigenetic DNA modifications, including DNA methylation. This is of interest as, the placenta is the interface between the fetus and its environment, the mother. Exposure to environmental toxins and nutrition during pregnancy may alter DNA methylation of the placenta and subsequently placental function and as a result the phenotype of the offspring. The aim of this study was to develop a reliable method to quantify DNA methylation in large clinical studies. This will be a tool to analyze the degree of DNA methylation in the human placenta in relationship to clinical readouts. Methods: Liquid chromatography-electrospray ionization/multi-stage mass spectrometry (LC-ESI/MS/MS technique was used for the quantification of the 5dmC/dG ratio in placentas from 248 healthy pregnancies. We were able to demonstrate that this method is a reliable and stable way to determine global placental DNA methylation in large clinical trials. Results/Conclusion: The degree of placental DNA methylation seen in our pilot study varies substantially from 2% to 5%. The clinical implications of this variation need to be demonstrated in adequately powered large studies.

  13. Determination of plant growth regulators in pears by microwave-assisted extraction and liquid chromatography with electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mao, Xuejin; Tang, Lijuan; Tan, Ting; Wan, Yiqun

    2014-06-01

    A new method for the determination of six plant growth regulators, 3-indolylacetic acid, 3-indolepropionic acid, 2-naphthoxyacetic acid, 2,4-dicholrophenoxyacetic acid, 1-naphthlcetic acid, and methyl naphthalene-1-acetate, in pears was established by liquid chromatography with electrospray ionization mass spectrometry. In this study, a microwave-assisted extraction technique was first applied for the determination of plant growth regulators in fruit and three cleanup techniques were, respectively, investigated for the purification of pear samples. The chromatographic separation was performed on a Diamonsil C18 column by using 0.01 mol/L formic acid/ammonium formate buffer solution (pH 3.5)/methanol (35:65, v/v) as the mobile phase with a flow rate of 0.7 mL/min in 1:1 split mode. The LODs ranged from 0.3 to 1.9 μg/kg. Under optimized conditions, the average recoveries (five replicates) for six plant growth regulators (spiked at 0.01, 0.05, and 0.5 mg/kg) ranged from 78.9 to 118.0%, and the RSDs were 1.4-10.3%.

  14. Screening for new psychoactive substances in hair by ultrahigh performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Strano-Rossi, Sabina; Odoardi, Sara; Fisichella, Marco; Anzillotti, Luca; Gottardo, Rossella; Tagliaro, Franco

    2014-11-06

    In the latest years, many new psychoactive substances (NPS) from several drug classes have appeared in the illicit drug market. Their rapid, sensitive and specific identification in biological fluids is hence of great concern for clinical and forensic toxicologists. Here is described a multi-analyte method for the determination of NPS, pertaining to different chemical classes (synthetic cannabinoids, synthetic cathinones, ketamine, piperazines and amphetamine-type substances-ATS) in human hair using ultrahigh performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) in electrospray ionization mode. We focused on a sample preparation able to extract the different classes of NPS. About 30mg of hair was decontaminated and incubated overnight under sonication in different conditions depending on the type of analytes to be extracted: (a) with 300μL of HCOOH 0.1% for cathinones, piperazines and ATS; (b) with 300μL of MeOH for synthetic cannabinoids. Ten microliter of the extracts were then injected in UHPLC-ESI-MS/MS in MRM mode. The LODs varied from 2pg/mg to 20pg/mg. The method was linear in the range from the LOQ to 500pg/mg and showed acceptable precision (%RSD<15) and accuracy (%E<15) for all the analytes. The method was finally applied on 50 samples from real forensic cases (driving license re-granting, postmortem toxicological analyses, workplace drug testing). In three samples we detected synthetic cannabinoids, in four samples cathinones or ephedrines, in two samples ketamine.

  15. Relationships between structure, ionization profile and sensitivity of exogenous anabolic steroids under electrospray ionization and analysis in human urine using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cha, Eunju; Kim, Sohee; Kim, Hee Won; Lee, Kang Mi; Kim, Ho Jun; Kwon, Oh-Seung; Lee, Jaeick

    2016-04-01

    The relationships between the ionization profile, sensitivity, and structures of 64 exogenous anabolic steroids (groups I-IV) was investigated under electrospray ionization (ESI) conditions. The target analytes were ionized as [M + H](+) or [M + H-nH2 O](+) in the positive mode, and these ions were used as precursor ions for selected reaction monitoring analysis. The collision energy and Q3 ions were optimized based on the sensitivity and selectivity. The limits of detection (LODs) were 0.05-20 ng/mL for the 64 steroids. The LODs for 38 compounds, 14 compounds and 12 compounds were in the range of 0.05-1, 2-5 and 10-20 ng/mL, respectively. Steroids including the conjugated keto-functional group at C3 showed good proton affinity and stability, and generated the [M + H](+) ion as the most abundant precursor ion. In addition, the LODs of steroids using the [M + H](+) ion as the precursor ion were mostly distributed at low concentrations. In contrast, steroids containing conjugated/unconjugated hydroxyl functional groups at C3 generated [M + H - H2 O](+) or [M + H - 2H2 O](+) ions, and these steroids showed relatively high LODs owing to poor stability and multiple ion formation. An LC-MS/MS method based on the present ionization profile was developed and validated for the determination of 78 steroids (groups I-V) in human urine.

  16. CREATININE DETERMINATION IN URINE BY LIQUID CHROMATOGRAPHY-ELECTROSPRAY IONIZATION-TANDEM MASS SPECTROMETRY METHOD.

    Science.gov (United States)

    Dereziński, Paweł; Klupczyńska, Agnieszka; Sawicki, Wojciech; Kokot, Zenon J

    2016-01-01

    Creatinine determination in urine is used to estimate the completeness of the 24-h urine collection, compensation for variable diuresis and as a preliminary step in protein profiling in urine. Despite the fact that a wide range of methods of measuring creatinine level in biofluids has been developed, many of them are adversely affected by interfering substances. A new liquid chromatography-tandem mass spectrometry method for creatinine determination in urine has been developed. Chromatographic separation was performed by applying C18 column and a gradient elution. Analyses were carried out on a triple quadrupole mass spectrometer equipped with an electrospray ion source. The developed method was fully validated according to the international guidelines. The quantification range of the method was 5-1500 ng/mL, which corresponds to 1-300 mg/dL in urine. Limit of detection and quantitation were 2 and 5 ng/mL, respectively. Additionally, the comparison of creatinine determination by newly developed method to the colorimetric method was performed. The method enables the determination of creatinine in urine samples with a minimal sample preparation, excellent sensitivity and prominent selectivity. Since mass spectrometry allows to measure a number of compounds simultaneously, a future perspective would be to incorporate the determination of other clinically important compounds excreted in urine.

  17. Xenon Fractionation and Archean Hydrogen Escape

    Science.gov (United States)

    Zahnle, K. J.

    2015-01-01

    Xenon is the heaviest gas found in significant quantities in natural planetary atmospheres. It would seem the least likely to escape. Yet there is more evidence for xenon escape from Earth than for any element other than helium and perhaps neon. The most straightforward evidence is that most of the radiogenic Xe from the decay of (129)I (half-life 15.7 Myr) and (244)Pu (half-life 81 Myr) that is Earth's birthright is missing. The missing xenon is often attributed to the impact erosion of early atmospheres of Earth and its ancestors. It is obvious that if most of the radiogenic xenon were driven off by impacts, most of the rest of the atmophiles fared the same fate. The other line of evidence is in the nonradiogenic isotopes of xenon and its silent partner, krypton. Atmospheric xenon is strongly mass fractionated (at about 4% per amu) compared to any known solar system source (Figure 1). This is in stark contrast to krypton, which may not be fractionated at all: atmospheric Kr is slightly heavier than solar Kr (at about 0.5% per amu), but it is the same as in carbonaceous chondrites. Nonradiogenic xenon is also under abundant relative to krypton (the so-called "missing xenon" problem). Together these observations imply that xenon has been subject to fractionating escape and krypton not.

  18. Breakdown characteristics of xenon HID Lamps

    Science.gov (United States)

    Babaeva, Natalia; Sato, Ayumu; Brates, Nanu; Noro, Koji; Kushner, Mark

    2009-10-01

    The breakdown characteristics of mercury free xenon high intensity discharge (HID) lamps exhibit a large statistical time lag often having a large scatter in breakdown voltages. In this paper, we report on results from a computational investigation of the processes which determine the ignition voltages for positive and negative pulses in commercial HID lamps having fill pressures of up to 20 atm. Steep voltage rise results in higher avalanche electron densities and earlier breakdown times. Circuit characteristics also play a role. Large ballast resistors may limit current to the degree that breakdown is quenched. The breakdown voltage critically depends on cathode charge injection by electric field emission (or other mechanisms) which in large part controls the statistical time lag for breakdown. For symmetric lamps, ionization waves (IWs) simultaneously develop from the bottom and top electrodes. Breakdown typically occurs when the top and bottom IWs converge. Condensed salt layers having small conductivities on the inner walls of HID lamps and on the electrodes can influence the ignition behavior. With these layers, IWs tend to propagate along the inner wall and exhibit a different structure depending on the polarity.

  19. A two-dimensional liquid-filled ionization chamber array prototype for small-field verification: characterization and first clinical tests.

    Science.gov (United States)

    Brualla-González, Luis; Gómez, Faustino; Vicedo, Aurora; González-Castaño, Diego M; Gago-Arias, Araceli; Pazos, Antonio; Zapata, Martín; Roselló, Joan V; Pardo-Montero, Juan

    2012-08-21

    In this work we present the design, characterization and first clinical tests of an in-house developed two-dimensional liquid-filled ionization chamber prototype for the verification of small radiotherapy fields and treatments containing such small fields as in radiosurgery, which consists of 2 mm × 2 mm pixels arranged on a 16×8 rectangular grid. The ionization medium is isooctane. The characterization of the device included the study of depth, field-size and dose-rate dependences, which are sufficiently moderate for a good operation at therapy radiation levels. However, the detector presents an important anisotropic response, up to ≃ 12% for front versus near-lateral incidence, which can impact the verification of full treatments with different incidences. In such a case, an anisotropy correction factor can be applied. Output factors of small square fields measured with the device show a small systematic over-response, less than 1%, when compared to unshielded diode measurements. An IMRT radiosurgery treatment has been acquired with the liquid-filled ionization chamber device and compared with film dosimetry by using the gamma method, showing good agreement: over 99% passing rates for 1.2% and 1.2 mm for an incidence-per-incidence analysis; 100% passing rates for tolerances 1.8% and 1.8 mm when the whole treatment is analysed and the anisotropy correction factor is applied. The point dose verification for each incidence of the treatment performed with the liquid-filled ionization chamber agrees within 1% with a CC01 ionization chamber. This prototype has shown the utility of this kind of technology for the verification of small fields/treatments. Currently, a larger device covering a 5 cm × 5 cm area is under development.

  20. Ionization signals from electrons and alpha-particles in mixtures of liquid Argon and Nitrogen - perspectives on protons for Gamma Resonant Nuclear Absorption applications

    CERN Document Server

    Zeller, M; Delaquis, S; Ereditato, A; Janos, S; Kreslo, I; Messina, M; Moser, U; Rossi, B

    2010-01-01

    In this paper we report on a detailed study of ionization signals produced by Compton electrons and alpha-particles in a Time Projection Chamber (TPC) flled with different mixtures of liquid Argon and Nitrogen. The measurements were carried out with Nitrogen concentrations up to 15% and a drift electric feld in the range 0-50 kV/cm. A prediction for proton ionization signals is made by means of interpolation. This study has been conducted in view of the possible use of liquid Ar-N2 TPCs for the detection of gamma-rays in the resonant band of the Nitrogen absorption spectrum, a promising technology for security and medical applications.

  1. Investigation and Applications of In-Source Oxidation in Liquid Sampling-Atmospheric Pressure Afterglow Microplasma Ionization (LS-APAG) Source.

    Science.gov (United States)

    Xie, Xiaobo; Wang, Zhenpeng; Li, Yafeng; Zhan, Lingpeng; Nie, Zongxiu

    2016-12-19

    A liquid sampling-atmospheric pressure afterglow microplasma ionization (LS-APAG) source is presented for the first time, which is embedded with both electrospray ionization (ESI) and atmospheric pressure afterglow microplasma ionization (APAG) techniques. This ion source is capable of analyzing compounds with diverse molecule weights and polarities. An unseparated mixture sample was detected as a proof-of-concept, giving complementary information (both polarities and non-polarities) with the two ionization modes. It should also be noted that molecular mass can be quickly identified by ESI with clean and simple spectra, while the structure can be directly studied using APAG with in-source oxidation. The ionization/oxidation mechanism and applications of the LS-APAG source have been further explored in the analysis of nonpolar alkanes and unsaturated fatty acids/esters. A unique [M + O - 3H](+) was observed in the case of individual alkanes (C5-C19) and complex hydrocarbons mixture under optimized conditions. Moreover, branched alkanes generated significant in-source fragments, which could be further applied to the discrimination of isomeric alkanes. The technique also facilitates facile determination of double bond positions in unsaturated fatty acids/esters due to diagnostic fragments (the acid/ester-containing aldehyde and acid oxidation products) generated by on-line ozonolysis in APAG mode. Finally, some examples of in situ APAG analysis by gas sampling and surface sampling were given as well. Graphical Abstract ᅟ.

  2. Characterization of proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by Flow Injection Analysis-Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Tala, Viviane Raïssa Sipowo; Candida da Silva, Viviane; Rodrigues, Clenilson Martins; Nkengfack, Augustin Ephrem; dos Santos, Lourdes Campaner; Vilegas, Wagner

    2013-03-01

    The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae) roots and barks by Liquid Chromatography-Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

  3. Characterization of Proanthocyanidins from Parkia biglobosa (Jacq. G. Don. (Fabaceae by Flow Injection Analysis — Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Wagner Vilegas

    2013-03-01

    Full Text Available The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

  4. New constraints and discovery potential of sub-GeV dark matter with xenon detectors

    Science.gov (United States)

    McCabe, Christopher

    2017-08-01

    Existing xenon dark matter (DM) direct detection experiments can probe the DM-nucleon interaction of DM with a sub-GeV mass through a search for photon emission from the recoiling xenon atom. We show that LUX's constraints on sub-GeV DM, which utilize the scintillation (S1) and ionization (S2) signals, are approximately 3 orders of magnitude more stringent than previous xenon constraints in this mass range, derived from the XENON10 and XENON100 S2-only searches. The new LUX constraints provide the most stringent direct detection constraints for DM particles with a mass below 0.5 GeV. In addition, the photon emission signal in LUX and its successor LZ maintain the discrimination between background and signal events so that an unambiguous discovery of sub-GeV DM is possible. We show that LZ has the potential to reconstruct the DM mass with ≃20 % accuracy for particles lighter than 0.5 GeV.

  5. High-Resolution Electrospray Ionization Mass Spectrometry Analysis of Water- Soluble Organic Aerosols Collected with a Particle into Liquid Sampler

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Adam P.; Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

    2010-10-01

    This work demonstrates the utility of a particle-into-liquid sampler (PILS) a technique traditionally used for identification of inorganic ions present in ambient or laboratory aerosols for the analysis of water soluble organic aerosol (OA) using high resolution electrospray ionization mass spectrometry (HR ESI-MS). Secondary organic aerosol (SOA) was produced from 0.5 ppm mixing ratios of limonene and ozone in a 5 m3 Teflon chamber. SOA was collected simultaneously using a traditional filter sampler and a PILS. The filter samples were later extracted with either water or acetonitrile, while the aqueous PILS samples were analyzed directly. In terms of peak intensities, types of detectable compounds, average O:C ratios, and organic mass to organic carbon ratios, the resulting high resolution mass spectra were essentially identical for the PILS and filter based samples. SOA compounds extracted from both filter/acetonitrile extraction and PILS/water extraction accounted for >95% of the total ion current in ESI mass spectra. This similarity was attributed to high solubility of limonene SOA in water. In contrast, significant differences in detected ions and peak abundances were observed for pine needle biomass burning organic aerosol (BBOA) collected with PILS and filter sampling. The water soluble fraction of BBOA is considerably smaller than for SOA, and a number of unique peaks were detectable only by the filter/acetonitrile method. The combination of PILS collection with HR-ESI-MS analysis offers a new approach for molecular analysis of the water-soluble organic fraction in biogenic SOA, aged photochemical smog, and BBOA.

  6. Identification of oxidized methionine sites in erythrocyte membrane protein by liquid chromatography/electrospray ionization mass spectrometry peptide mapping.

    Science.gov (United States)

    Li, Chunyan; Takazaki, Shinya; Jin, Xiuri; Kang, Dongchon; Abe, Yoshito; Hamasaki, Naotaka

    2006-10-03

    In this study, we used peptide mapping combined with liquid chromatography/electrospray ionization mass spectrometry (LC/ESI MS) to examine the methionine oxidation of band 3 of erythrocyte membrane protein. Initially, we identified the methionine sites oxidized by chloramine T (N-chloro-p-toluenesulfoamide), a hydrophilic reagent. There were three oxidized methionines (Met 559, Met 741, and Met 909) in band 3, and these methionines were located in a hydrophilic region determined by previous topological studies of band 3. In addition, we found that C12E8, a polyoxyethylene detergent, leads to the oxidation of methionines in a transmembrane segment in band 3, and this oxidation occurs in a C12E8 preincubation time-dependent manner. In a previous study, it was found that peroxides accumulate in a polyoxyethylene detergent. Thus, our method enabled the direct and quantitative detection of protein damage due to detergent peroxides. Furthermore, we examined methionine oxidation in the presence of 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS) or diethyl pyrocarbonate (DEPC), which induced either an outward or an inward conformation in band 3, respectively. Our results indicated that the location of Met 741 was associated with the band 3 conformation induced by band 3-mediated anion transport. In conclusion, we found that methionine oxidation can be applied to examine membrane protein structures as follows: (1) for topological studies of membrane proteins, (2) for assessing the quality of proteins in detergent solubilization studies, and (3) for the detection of conformational changes in membrane proteins.

  7. SU-E-T-105: The LET Dependence of Liquid Ionization Chambers (LICs) in High-LET Beams.

    Science.gov (United States)

    Tegami, S; Gomez, F; Gónzales-Castaño, D; Jaekel, O; Pardo-Montero, J; Holzscheiter, M

    2012-06-01

    LICs are novel detectors for radiotherapy: the higher density of the medium allows to build them with a smaller sensitive volume, making them appealing in particle therapy. With RBE varying along the depth dose curve (DDC) and with the rising interest in dose/LET-painting, verifying the LET is becoming more important. Nevertheless, while the LET distributions for different ionizing particles have been calculated, they have never been directly measured in realistic therapeutic beams. Our interest in LICs is based on the characterization of the beam quality in terms of LET. It has been shown in earlier works that the extrapolation of the linear portion of the voltage curve yields an intercept with the x-axis that depends on LET. The quantitative establishment of this method, however, depends on how accurately recombination effects are taken into account. Due to the higher density of charge carriers produced in the liquid, LICs have high recombination effects: general recombination effects, involving pairs belonging to different tracks (dose rate dependent), and initial recombination between ion-electron pairs belonging to the same incident particle event (LET dependent). To perform this study we propose a two-dimensional array of LICs, composed by a 16×8 matrix of 2×2 mm(2) pixels, which gives a fine spatial resolution on the plane. Voltage curves have been measured for proton, carbon and oxygen beams available at the HIT facility in Heidelberg for different energies and dose rates. After correcting the curves for general recombination losses using the Three Voltage Method, we have indications of dose rate independence, indicating successful correction. Further investigations are foreseen to quantify the LET dependence along the DDC, where different LET values are expected. A comparison with simulated dose averaged LET values will give quantitative information about 2D LET distributions for different beam species. © 2012 American Association of Physicists in

  8. Retention behavior of lipids in reversed-phase ultrahigh-performance liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Ovčačíková, Magdaléna; Lísa, Miroslav; Cífková, Eva; Holčapek, Michal

    2016-06-10

    Reversed-phase ultrahigh-performance liquid chromatography (RP-UHPLC) method using two 15cm sub-2μm particles octadecylsilica gel columns is developed with the goal to separate and unambiguously identify a large number of lipid species in biological samples. The identification is performed by the coupling with high-resolution tandem mass spectrometry (MS/MS) using quadrupole - time-of-flight (QTOF) instrument. Electrospray ionization (ESI) full scan and tandem mass spectra are measured in both polarity modes with the mass accuracy better than 5ppm, which provides a high confidence of lipid identification. Over 400 lipid species covering 14 polar and nonpolar lipid classes from 5 lipid categories are identified in total lipid extracts of human plasma, human urine and porcine brain. The general dependences of relative retention times on relative carbon number or relative double bond number are constructed and fit with the second degree polynomial regression. The regular retention patterns in homologous lipid series provide additional identification point for UHPLC/MS lipidomic analysis, which increases the confidence of lipid identification. The reprocessing of previously published data by our and other groups measured in the RP mode and ultrahigh-performance supercritical fluid chromatography on the silica column shows more generic applicability of the polynomial regression for the description of retention behavior and the prediction of retention times. The novelty of this work is the characterization of general trends in the retention behavior of lipids within logical series with constant fatty acyl length or double bond number, which may be used as an additional criterion to increase the confidence of lipid identification.

  9. Confirmatory determination of six penicillins in honey by liquid chromatography/electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Jian

    2004-01-01

    A confirmatory method for 6 penicillin antibiotics (amoxicillin, ampicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin) in honey is presented that allows determination and confirmation of identity of the antibiotics at trace levels. The method includes the use of a stable isotope-labeled internal standard benzyl (d7-phenyl) penicillate and removal of sugar and other substances by solvent and solid-phase extraction. The honey extracts are then analyzed for penicillin residues by liquid chromatography/electrospray ionization-tandem mass spectrometry. Mass spectral acquisition was achieved in an electrospray positive ion mode by applying multiple reaction monitoring of 2 or 3 fragment ion transitions to provide a high degree of sensitivity and specificity. Typical recoveries of 6 penicillins at fortification levels of 6, 16, 40, and 80 microg/kg ranged from 51.4 to 132.9%. The recoveries varied with the individual penicillins and were affected by different honey matrixes. The ion ratios were consistent and could be used for confirmation of identity of the penicillins. The method limits of detection (microg/kg) were 0.25 for amoxicillin, 0.19 for ampicillin, 0.068 for penicillin G, 0.028 for oxacillin, 0.052 for cloxacillin, and 0.085 for dicloxacillin. The method limits of confirmation (microg/kg) were 0.44 for amoxicillin, 0.52 for ampicillin, 0.23 for penicillin G, 0.14 for oxacillin, 0.14 for cloxacillin, and 0.15 for dicloxacillin when a sample size of 5 g honey was used.

  10. Monitoring Toxic Ionic Liquids in Zebrafish (Danio rerio) with Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI-MSI)

    Science.gov (United States)

    Perez, Consuelo J.; Tata, Alessandra; de Campos, Michel L.; Peng, Chun; Ifa, Demian R.

    2016-10-01

    Ambient mass spectrometry imaging has become an increasingly powerful technique for the direct analysis of biological tissues in the open environment with minimal sample preparation and fast analysis times. In this study, we introduce desorption electrospray ionization mass spectrometry imaging (DESI-MSI) as a novel, rapid, and sensitive approach to localize the accumulation of a mildly toxic ionic liquid (IL), AMMOENG 130 in zebrafish (Danio rerio). The work demonstrates that DESI-MSI has the potential to rapidly monitor the accumulation of IL pollutants in aquatic organisms. AMMOENG 130 is a quaternary ammonium-based IL reported to be broadly used as a surfactant in commercialized detergents. It is known to exhibit acute toxicity to zebrafish causing extensive damage to gill secondary lamellae and increasing membrane permeability. Zebrafish were exposed to the IL in a static 96-h exposure study in concentrations near the LC50 of 1.25, 2.5, and 5.0 mg/L. DESI-MS analysis of zebrafish gills demonstrated the appearance of a dealkylated AMMOENG 130 metabolite in the lowest concentration of exposure identified by a high resolution hybrid LTQ-Orbitrap mass spectrometer as the trimethylstearylammonium ion, [C21H46N]+. With DESI-MSI, the accumulation of AMMOENG 130 and its dealkylated metabolite in zebrafish tissue was found in the nervous and respiratory systems. AMMOENG 130 and the metabolite were capable of penetrating the blood brain barrier of the fish with significant accumulation in the brain. Hence, we report for the first time the simultaneous characterization, distribution, and metabolism of a toxic IL in whole body zebrafish analyzed by DESI-MSI. This ambient mass spectrometry imaging technique shows great promise for the direct analysis of biological tissues to qualitatively monitor foreign, toxic, and persistent compounds in aquatic organisms from the environment.

  11. Rapid and sensitive hormonal profiling of complex plant samples by liquid chromatography coupled to electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Müller Maren

    2011-11-01

    Full Text Available Abstract Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific developmental pathways and physiological responses. Due to the presence of hormones at very low concentrations in plant tissues (10-9 M to 10-6 M and their different chemistries, the development of a high-throughput and comprehensive method for the determination of hormones is challenging. Results The present work reports a rapid, specific and sensitive method using ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UPLC/ESI-MS/MS to analyze quantitatively the major hormones found in plant tissues within six minutes, including auxins, cytokinins, gibberellins, abscisic acid, 1-amino-cyclopropane-1-carboxyic acid (the ethylene precursor, jasmonic acid and salicylic acid. Sample preparation, extraction procedures and UPLC-MS/MS conditions were optimized for the determination of all plant hormones and are summarized in a schematic extraction diagram for the analysis of small amounts of plant material without time-consuming additional steps such as purification, sample drying or re-suspension. Conclusions This new method is applicable to the analysis of dynamic changes in endogenous concentrations of hormones to study plant developmental processes or plant responses to biotic and abiotic stresses in complex tissues. An example is shown in which a hormone profiling is obtained from leaves of plants exposed to salt stress in the aromatic plant, Rosmarinus officinalis.

  12. Shear Thinning Near the Critical Point of Xenon

    Science.gov (United States)

    Zimmerli, Gregory A.; Berg, Robert F.; Moldover, Michael R.; Yao, Minwu

    2008-01-01

    We measured shear thinning, a viscosity decrease ordinarily associated with complex liquids, near the critical point of xenon. The data span a wide range of reduced shear rate: 10(exp -3) critical fluctuations. The measurements had a temperature resolution of 0.01 mK and were conducted in microgravity aboard the Space Shuttle Columbia to avoid the density stratification caused by Earth's gravity. The viscometer measured the drag on a delicate nickel screen as it oscillated in the xenon at amplitudes 3 mu,m 430 mu, and frequencies 1 Hz critical scaling. At high frequencies, (omega tau)(exp 2) > gamma-dot tau, C(sub gamma) depends also on both x(sub 0) and omega. The data were compared with numerical calculations based on the Carreau-Yasuda relation for complex fluids: eta(gamma-dot)/eta(0)=[1+A(sub gamma)|gamma-dot tau|](exp - chi(sub eta)/3+chi(sub eta)), where chi(sub eta) =0.069 is the critical exponent for viscosity and mode-coupling theory predicts A(sub gamma) =0.121. For xenon we find A(sub gamma) =0.137 +/- 0.029, in agreement with the mode coupling value. Remarkably, the xenon data close to the critical temperature T(sub c) were independent of the cooling rate (both above and below T(sub c) and these data were symmetric about T(sub c) to within a temperature scale factor. The scale factors for the magnitude of the oscillator s response differed from those for the oscillator's phase; this suggests that the surface tension of the two-phase domains affected the drag on the screen below T(sub c).

  13. Xenon Fractionation, Hydrogen Escape, and the Oxidation of the Earth

    Science.gov (United States)

    Zahnle, K. J.; Catling, D. C.

    2014-12-01

    Xenon in Earth's atmosphere is severely mass fractionated and depleted compared to any plausible solar system source material, yet Kr is unfractionated. These observations seem to imply that Xe has escaped from Earth. Vigorous hydrodynamic hydrogen escape can produce mass fractionation in heavy gases. The required hydrogen flux is very high but within the range permitted by solar EUV heating when Earth was 100 Myrs old or younger. However this model cannot explain why Xe escapes but Kr does not. Recently, what appears to be ancient atmospheric xenon has been recovered from several very ancient (3-3.5 Ga) terrestrial hydrothermal barites and cherts (Pujol 2011, 2013). What is eye-catching about this ancient Xe is that it is less fractionated that Xe in modern air. In other words, it appears that a process was active on Earth some 3 to 3.5 billion years ago that caused xenon to fractionate. By this time the Sun was no longer the EUV source that it used to be. If xenon was being fractionated by escape — currently the only viable hypothesis — it had to be in Earth's Archean atmosphere and under rather modest levels of EUV forcing. It should be possible for Xe, but not Kr, to escape from Earth as an ion. In a hydrodynamically escaping hydrogen wind the hydrogen is partially ionized. The key concepts are that ions are much more strongly coupled to the escaping flow than are neutrals (so that a relatively modest flow of H and H+ to space could carry Xe+ along with it, the flux can be small enough to be consistent with diffusion-limited flux), and that Xe alone among the noble gases is more easily ionized than hydrogen. This sort of escape is possible along the polar field lines, although a weak or absent magnetic field would likely work as well. The extended history of hydrogen escape implicit in Xe escape in the Archean is consistent with other suggestions that hydrogen escape in the Archean was considerable. Hydrogen escape plausibly played the key role in creating

  14. Xenon Gamma Detector Project Support

    Energy Technology Data Exchange (ETDEWEB)

    Vanier,P.E.; Forman, L.

    2008-04-01

    This project provided funding of $48,500 for part of one year to support the development of compressed xenon spectrometers at BNL. This report describes upgrades that were made to the existing detector system electronics during that period, as well as subsequent testing with check sources and Special Nuclear Materials. Previous testing of the equipment extended only up to the energy of 1.3 MeV, and did not include a spectrum of Pu-239. The new electronics allowed one-button activation of the high voltage ramp that was previously controlled by manual adjustments. Mechanical relays of the charging circuit were replaced by a tera-ohm resistor chain and an optical switch. The preamplifier and shaping amplifier were replaced by more modern custom designs. We found that the xenon purity had not been degraded since the chamber was filled 10 years earlier. The resulting spectra showed significantly better resolution than sodium iodide spectra, and could be analyzed quite effectively by methods using peak area templates.

  15. Diffusion NMR methods applied to xenon gas for materials study

    Science.gov (United States)

    Mair, R. W.; Rosen, M. S.; Wang, R.; Cory, D. G.; Walsworth, R. L.

    2002-01-01

    We report initial NMR studies of (i) xenon gas diffusion in model heterogeneous porous media and (ii) continuous flow laser-polarized xenon gas. Both areas utilize the pulsed gradient spin-echo (PGSE) techniques in the gas phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients--a brief overview of this area is provided in the Introduction. The heterogeneous or multiple-length scale model porous media consisted of random packs of mixed glass beads of two different sizes. We focus on observing the approach of the time-dependent gas diffusion coefficient, D(t) (an indicator of mean squared displacement), to the long-time asymptote, with the aim of understanding the long-length scale structural information that may be derived from a heterogeneous porous system. We find that D(t) of imbibed xenon gas at short diffusion times is similar for the mixed bead pack and a pack of the smaller sized beads alone, hence reflecting the pore surface area to volume ratio of the smaller bead sample. The approach of D(t) to the long-time limit follows that of a pack of the larger sized beads alone, although the limiting D(t) for the mixed bead pack is lower, reflecting the lower porosity of the sample compared to that of a pack of mono-sized glass beads. The Pade approximation is used to interpolate D(t) data between the short- and long-time limits. Initial studies of continuous flow laser-polarized xenon gas demonstrate velocity-sensitive imaging of much higher flows than can generally be obtained with liquids (20-200 mm s-1). Gas velocity imaging is, however, found to be limited to a resolution of about 1 mm s-1 owing to the high diffusivity of gases compared with liquids. We also present the first gas-phase NMR scattering, or diffusive-diffraction, data, namely flow-enhanced structural features in the echo attenuation data from laser-polarized xenon flowing through a 2 mm glass bead pack. c2002 John Wiley & Sons, Ltd.

  16. High performance liquid chromatography-electrospray ionization-mass spectrometry with programmed ionization mode switching and time segment scanning approach for quantifying multi-components in traditional complex herbal medicines, Qiong-Yu-Gao as an example.

    Science.gov (United States)

    Xu, Jin-Di; Wu, Jie; Zhou, Shan-Shan; Shen, Hong; Mao, Qian; Zhu, He; Kong, Ming; Li, Song-Lin

    2015-08-10

    An improved high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method was developed to quantitatively evaluate the holistic quality of traditional complex herbal medicines (CHMs). Qiong-Yu-Gao (QYG), a classical CHM consisting of Rehmanniae Radix, Poriae and Ginseng Radix, was used as an example. Thirty-eight major components (including six pairs of epimers/isomers) belonging to five chemical types, i.e., iridoid glycosides, phenethylacohol glycosides, furfural derivatives, ginsenosides and triterpenoid acids, were selected as marker compounds. Programmed ionization mode switching and time segment scanning were designed to improve the sensitivity of the MS detection concerning the diverse chemical features of the analytes. The reference compounds of the analytes were individually injected directly into MS to optimize the ionization cone voltage and to select monitoring ion of each analyte. Nine channels with eight time segments were determined for monitoring the thirty-eight analytes, among which six were detected in positive and thirty-two in negative ion modes respectively. Higher signal-to-noise ratios of the analytes were achieved when compared with full time scanning. In addition, the linearity, precision, accuracy and stability of the method were also validated. The established method was applied for the quantitative evaluation of QYG samples prepared with three different methods. Obvious difference in the contents of thirty-eight components, in particular the original ginsenosides, degraded ginsenosides and furfural derivatives, was found among these QYG samples. All these results demonstrated that the established HPLC-ESI-MS with programmed ionization mode switching and time segment scanning approach is very suitable for the standardization investigation of CHMs.

  17. Structures of xenon oxides at high pressures

    Science.gov (United States)

    Worth, Nicholas; Pickard, Chris; Needs, Richard; Dewaele, Agnes; Loubeyre, Paul; Mezouar, Mohamed

    2014-03-01

    For many years, it was believed that noble gases such as xenon were entirely inert. It was only in 1962 that Bartlett first synthesized a compound of xenon. Since then, a number of other xenon compounds, including oxides, have been synthesized. Xenon oxides are unstable under ambient conditions but have been predicted to stabilize under high pressure. Here we present the results of a combined theoretical and experimental study of xenon oxides at pressures of 80-100 GPa. We have synthesized new xenon oxides at these pressures and they have been characterized with X-ray diffraction and Raman spectroscopy. Calculations were performed with a density-functional theory framework. We have used the ab-initio random structure searching (AIRSS) method together with a data-mining technique to determine the stable compounds in the xenon-oxygen system in this pressure range. We have calculated structural and optical properties of these phases, and a good match between theoretical and experimental results has been obtained. Funding for computational research provided by the engineering and physical sciences research council (EPSRC; UK). Computing resources provided by Cambridge HPC and HECToR. X-ray diffraction experiments performed at ESRF.

  18. Hydrophilic interaction chromatography versus reversed phase liquid chromatography coupled to mass spectrometry: effect of electrospray ionization source geometry on sensitivity.

    Science.gov (United States)

    Periat, Aurélie; Kohler, Isabelle; Bugey, Aurélie; Bieri, Stefan; Versace, François; Staub, Christian; Guillarme, Davy

    2014-08-22

    In this study, the influence of electrospray ionization (ESI) source design on the overall sensitivity achieved in hydrophilic interaction chromatography (HILIC) and reversed phase liquid chromatography (RPLC), was investigated. State-of-the-art triple quadrupole mass analyzers from AB Sciex, Agilent Technologies and Waters equipped with brand specific source geometries were tested with various mobile phase pH on 53 pharmaceutical compounds. The design of the ESI source showed to strongly influence the gain in sensitivity that can be achieved in HILIC compared to RPLC mode. The 6460 Triple Quadrupole LC/MS system from Agilent Technologies was particularly affected by mobile phase settings. Indeed, compared to RPLC conditions, 92% of the compounds had an increased signal-to-noise ratio at a flow rate of 300 μL/min in HILIC mode at pH 6, while this percentage dropped to only 7% at 1000 μL/min and pH 3. In contrast, the influence of flow rate and mobile phase pH on the gain in sensitivity between RPLC and HILIC was found very limited with the API 5000 LC/MS/MS system from AB Sciex, as only 15 to 36% of the tested compounds showed an enhanced sensitivity in HILIC mode. With the Xevo TQ-S instrument from Waters, superior sensitivity in HILIC was noticed for 85% of the compounds with optimal conditions (i.e., pH 3 and 1000 μL/min), whereas at sub-optimal conditions (i.e. pH 6 and 300 μL/min), it represented less than 50%. The gain in sensitivity observed in HILIC was found less significant with the recent LC-MS platforms used in this study than for old-generation instruments. Indeed, the improved ESI sources equipping the recent mass analyzers allow for enhanced evaporation efficiency, mainly for RPLC mobile phases containing high proportion of water and this even at high flow rates. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Cloud-point extraction is compatible with liquid chromatography coupled to electrospray ionization mass spectrometry for the determination of bisoprolol in human plasma.

    Science.gov (United States)

    Giebułtowicz, Joanna; Kojro, Grzegorz; Buś-Kwaśnik, Katarzyna; Rudzki, Piotr J; Marszałek, Ryszard; Leś, Andrzej; Wroczyński, Piotr

    2015-12-04

    Cloud-point extraction (CPE) draws increasing interest in a number of analytical fields including bioanalysis, but combining CPE and LC-MS with electrospray ionization (ESI) in the determination of drugs in biological fluids such as plasma, serum or blood has not been reported so far. Bisoprolol was determined in human plasma by CPE using Trition X-114 as a surfactant and metoprolol as the internal standard. NaOH concentration, temperature and Trition X-114 concentration were optimized. All analyses were performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). All validation experiments met international acceptance criteria and no significant matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples and appropriate statistical tests. The determination of bisoprolol concentration in human plasma in the range 1.0-70ngmL(-1) by the CPE method leads to the results which are equivalent to those obtained by the widely used liquid-liquid extraction method. The results revealed that a structural analogue may be an appropriate internal standard when CPE is used as the extraction technique. CPE offers significant practical advantages over the classical extraction methods, including a positive impact on the environment, therefore its wider application in future pharmacokinetic studies is justifiable.

  20. Position Reconstruction of Bubble Formation in Liquid Nitrogen using Piezoelectric Sensors

    CERN Document Server

    Lenardo, Brian; Manalaysay, Aaron; Morad, James; Payne, Chrisman; Stephenson, Scott; Szydagis, Matthew; Tripathi, Mani

    2015-01-01

    Cryogenic liquids, particularly liquid xenon and argon, are of interest as detector media for experiments in nuclear and particle physics. Here we present a new detector diagnostic technique using piezoelectric sensors to detect bubbling of the liquid. Bubbling can indicate locations of excess heat dissipation e.g., in immersed electronics. They can also interfere with normal event evolution by scattering of light or by interrupting the drift of ionization charge. In our test apparatus, four sensors are placed in the vacuum space of a double-walled dewar of liquid nitrogen and used to detect and locate a source of bubbling inside the liquid volume. Utilizing the differences in transmitted frequencies through the different media present in the experiment, we find that sound traveling in a direct path from the source to the sensor can be isolated with appropriate filtering. The location of the source is then reconstructed using the time difference of arrivals (TDOA) information. The reconstruction algorithm is ...

  1. Final Technical Report for Award DE-FG02-05ER41389 A New Electrostatically-Focused, UV HPD for Liquid Xenon: A Direct Comparison with APD, PMT, SiPM in an Integrated Database

    Energy Technology Data Exchange (ETDEWEB)

    Elena Aprile

    2009-08-25

    Within the scope of the project, a LXe detector and associated gas handling and purification system were set up to study the response of various photodetectors to the VUV Xe light. In particular we tested an Advanced Photonix Large Area Avalanche Photodiode (APD), Silicon Photomultipliers (SiPMs) from two different sources and an Hamamtsu Photonics APD. As part of the XENON Dark Matter project, sponsored by the National Science Foundation, we have accumulated independent knowledge of the response of compact metal channel photomultipliers. At this stage, we conclude that the last are far superior in terms of reliability and performance in a LXe detector environment. More studies are needed with APDs and SiPMs in LXe, taking advantage of the improved performance of these sensors with time. We could not test a hybrid PMT (HPD) since the only available unit on loan from one manufacturer lacked the mechanical stability and was packaged in a form not compatible with LXe purity requirements. Meanwhile, within the XENON collaboration, we are developing with Hamamatsu a hybrid PMT which is named QUPID (Quartz Photon Intensifying Detector) which promises to solve the problems of radioactivity and purity encountered with previous HPDs. We attach to this report two papers which summarize in detail the experimental st-ups, procedures and results obtained with different APDs and SiPMs operated in LXe. We continue our investigations of APDs in view of their potential appication in large arrays for LXe detectors. We intend to publish the results once we complete tests of newly acquired Hamamatsu APDs.

  2. Rapid and simultaneous determination of sulfonate ester genotoxic impurities in drug substance by liquid chromatography coupled to tandem mass spectrometry: comparison of different ionization modes.

    Science.gov (United States)

    Guo, Tian; Shi, Yuanyuan; Zheng, Li; Feng, Feng; Zheng, Feng; Liu, Wenyuan

    2014-08-15

    Two ionization techniques for liquid chromatography-mass spectrometry (LC-MS) determination of sulfonate ester potentially genotoxic impurities (PGIs) were evaluated. Twelve PGIs including methyl, ethyl, propyl and isopropyl esters of methanesulfonate, benzenesulfonate and p-toluenesulfonate were studied in this research. Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) sources were compared in terms of performance and quality parameters for detection of the twelve PGIs. Their mass spectra obtained by APCI and ESI were very different in both fragment ions and relative abundances. In APCI negative ion mode the twelve sulfonate esters showed their stable precursor ions of [M-alkyl](-), which readily yielded product ions of [M-alkyl-CH3](-) (for aliphatic sulfonate esters) or [M-alkyl-SO2](-) (for aromatic sulfonate esters) with collision-induced dissociation (CID) applied; and working in selected reaction monitoring (SRM) mode has allowed limits of detection to be decreased. In the case of ESI ionization, these compounds showed their precursor ions [M+H](+), but their abundance was easily competed by formation of ions [M+NH4](+) and/or [M+Na](+), which led to poor analytical sensitivity and reproducibility. Although mobile phase additives could enhance the responses of adduct ions like [M+NH4](+) and [M+Na](+), no improvement was obtained when using SRM mode. Twelve sulfonate esters were systematically compared and APCI was shown to be a better ionization technique for rapid and sensitive determination of these PGIs. Performance of the developed approach for rapid determination of 12 PGIs was also evaluated. Quality parameters were established and good precision (relative standard deviations <8%) and very low limits (2-4ng/mL) of detection were obtained, mainly when using APCI in SRM mode.

  3. Stability studies of propoxur herbicide in environmental water samples by liquid chromatography-atmospheric pressure chemical ionization ion-trap mass spectrometry.

    Science.gov (United States)

    Sun, Lei; Lee, Hian Kee

    2003-10-01

    Liquid chromatography-atmospheric pressure ionization ion-trap mass spectrometry has been investigated for the analysis of polar pesticides in water. The degradation behavior of propoxur, selected as a model pesticide belonging to the N-methylcarbamate group, in various aqueous matrices (Milli-Q water, drinking water, rain water, seawater and river water) was investigated. Two interfaces of atmospheric pressure ionization, atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), were compared during the study. Propoxur and its transformation product (N-methylformamide) were best ionized as positive ions with both APCI and ESI, while another transformation product (2-isopropoxyphenol) yielded stronger signals as negative ions only with APCI. In addition, the effects of various pH, matrix type and irradiation sources (sunlight, darkness, indoor lighting and artificial UV lamp) on the chemical degradation (hydrolysis) were also assessed. From the kinetic studies of degradation, it was found that the half-life of propoxur was reduced from 327 to 161 h in Milli-Q water with variation of irradiation conditions from dark to sunlight exposure. Degradation rates largely increased with increasing pH. The half-life of the target compound dissolved in Milli-Q water under darkness decreased from 407 to 3 h when the pH of Milli-Q water was increased from 5 to 8.5. These suggest that hydrolysis of propoxur is light-intensity and pH-dependent. In order to mimic contaminated natural environmental waters, propoxur was spiked into real water samples at 30 microg/l. The degradation of propoxur in such water samples under various conditions were studied in detail and compared. With the ion trap run in a time-scheduled single ion monitoring mode, typical limits of detection of the instrument were in the range of 1-10 microg/l.

  4. PREPARATION OF ACTIVATED CARBON FIBER AND THEIR XENON ADSORPTION PROPERTIES (Ⅱ)-XENON ADSORPTION PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The adsorption of xenon from air has an interest in the monitoring of nuclear explosion oraccident, or in the treatment of nuclear waste gas. In this paper, the pore structure of several series ofactivated carbon fibers has been characterized. The adsorption properties of xenon on theseactivated carbon fibers under different temperatures have been studied in details. The results showthat the xenon adsorption amount on activated carbon fibers do not increase with specific surfacearea of adsorbents, but are closely related to their pore size distribution. Pores whose radius equal toor narrow than 0.4nm would be more advantageous to the adsorption of xenon.

  5. A simple high-sensitivity technique for purity analysis of xenon gas

    CERN Document Server

    Leonard, D S; Hall, C; Kaufman, L; Langford, T; Slutsky, S; Yen, Y R

    2010-01-01

    We report on the development and performance of a high-sensitivity purity-analysis technique for gaseous xenon. The gas is sampled at macroscopic pressure from the system of interest using a UHV leak valve. The xenon present in the sample is removed with a liquid-nitrogen cold trap, and the remaining impurities are observed with a standard vacuum mass-spectroscopy device. Using calibrated samples of xenon gas spiked with known levels of impurities, we find that the minimum detectable levels of N2, O2, and methane are 1 ppb, 160 ppt, and 60 ppt respectively. This represents an improvement of about a factor of 10,000 compared to measurements performed without a coldtrap.

  6. Dark matter results from 100 live days of XENON100 data.

    Science.gov (United States)

    Aprile, E; Arisaka, K; Arneodo, F; Askin, A; Baudis, L; Behrens, A; Bokeloh, K; Brown, E; Bruch, T; Bruno, G; Cardoso, J M R; Chen, W-T; Choi, B; Cline, D; Duchovni, E; Fattori, S; Ferella, A D; Gao, F; Giboni, K-L; Gross, E; Kish, A; Lam, C W; Lamblin, J; Lang, R F; Levy, C; Lim, K E; Lin, Q; Lindemann, S; Lindner, M; Lopes, J A M; Lung, K; Undagoitia, T Marrodán; Mei, Y; Fernandez, A J Melgarejo; Ni, K; Oberlack, U; Orrigo, S E A; Pantic, E; Persiani, R; Plante, G; Ribeiro, A C C; Santorelli, R; dos Santos, J M F; Sartorelli, G; Schumann, M; Selvi, M; Shagin, P; Simgen, H; Teymourian, A; Thers, D; Vitells, O; Wang, H; Weber, M; Weinheimer, C

    2011-09-23

    We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time-projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as the ultralow background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic weakly interacting massive particle (WIMP) nucleon scattering cross sections above 7.0 × 10(-45) cm(2) for a WIMP mass of 50 GeV/c(2) at 90% confidence level.

  7. Development and Comparison of Three Liquid Chromatography-Atmospheric Pressure Chemical Ionization/Mass Spectrometry Methods for Determining Vitamin D Metabolites in Human Serum

    OpenAIRE

    Bedner, Mary; Karen W. Phinney

    2012-01-01

    Liquid chromatographic methods with atmospheric pressure chemical ionization mass spectrometry were developed for the determination of the vitamin D metabolites 25-hydroxyvitamin D2 (25(OH)D2), 25-hydroxyvitamin D3 (25(OH)D3), and 3-epi-25-hydroxyvitamin-D3 (3-epi-25(OH)D3) in the four Levels of SRM 972, Vitamin D in Human Serum. One method utilized a C18 column, which separates 25(OH)D2 and 25(OH)D3, and one method utilized a CN column that also resolves the diastereomers 25(OH)D3 and 3-epi-...

  8. Identification and quantification of flavonoids in human urine samples by column switching liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Salka E.; Freese, R.; Cornett, C.

    2000-01-01

    A rapid and sensitive high-performance liquid chromatographic mass spectrometric (HPLC-MS) method is described for the determination and quantification of 12 dietary flavonoid glycosides and aglycons in human urine samples. Chromatographic separation of the analytes of interest was achieved...... by column-switching, using the first column (a Zorbax 300SB C-3 column) for sample cleanup and eluting the heart-cut flavonoid fraction onto the second column (a Zorbax SE C-18 column) for separation and detection by ultraviolet and atmospheric pressure chemical ionization MS using single ion monitoring...... with high and low flavonoid content was analyzed, and the results are reported....

  9. Main polyphenols in the bitter taste of virgin olive oil. Structural confirmation by on-line high-performance liquid chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Gutiérrez-Rosales, F; Ríos, J J; Gómez-Rey, Ma L

    2003-09-24

    Twenty virgin olive oils of extra quality and different bitter intensity were submitted to sensory evaluation and to the determination of polyphenols. A linear regression analysis was carried out assuming, as an independent variable, bitter intensity perceived by tasters, as an independent variable, the concentration (mmol/kg) of dialdehydic and aldehydic forms oleuropein aglycon, and dialdehydic and aldehydic forms ligstroside aglycon. Structural confirmation of these compounds was done by online high-performance liquid chromatography-electrospray ionization-collison-induced dissociation-mass spectrometry. The results obtained demonstrate the essential role played by this compound in the bitter taste of virgin olive oil.

  10. Quantification of β-carotene, retinol, retinyl acetate and retinyl palmitate in enriched fruit juices using dispersive liquid-liquid microextraction coupled to liquid chromatography with fluorescence detection and atmospheric pressure chemical ionization-mass spectrometry.

    Science.gov (United States)

    Viñas, Pilar; Bravo-Bravo, María; López-García, Ignacio; Hernández-Córdoba, Manuel

    2013-02-01

    A detailed optimization of dispersive liquid-liquid microextraction (DLLME) was carried out for developing liquid chromatographic (HPLC) techniques, using both fluorescence and atmospheric pressure chemical ionization mass spectrometric (APCI-MS) detection, for the simultaneous analysis of preforms of vitamin A: retinol (R), retinyl acetate (RA), retinyl palmitate (RP) and β-carotene (β-C). The HPLC analyses were carried out using a mobile phase composed of methanol and water, with gradient elution. The APCI-MS and fluorescence spectra permitted the correct identification of compounds in the analyzed samples. Parameters affecting DLLME were optimized using 2 mL of methanol (disperser solvent) containing 150 μL carbon tetrachloride (extraction solvent). The precision ranged from 6% to 8% (RSD) and the limits of detection were between 0.03 and 1.4 ng mL(-1), depending on the compound. The enrichment factor values were in the 21-44 range. Juice samples were analyzed without saponification and no matrix effect was found when using fluorescence detection, so calibration was possible with aqueous standards. However, a matrix effect appeared with APCI-MS, in which case it was necessary to apply matrix-matched calibration. There was great variability in the forms of vitamin A present in the juices, the most abundant ester being retinyl acetate (0.04 to 3.4 μg mL(-1)), followed by the amount of retinol (0.01 to 0.16 μg mL(-1)), while retinyl palmitate was not detected, except in the milk-containing juice, in which RP was the main form. The representative carotenoid β-carotene was present in the orange, peach, mango and multifruit juices in high amounts. The method was validated using two certified reference materials.

  11. Cloud-point extraction is compatible with liquid chromatography coupled to electrospray ionization mass spectrometry for the determination of antazoline in human plasma.

    Science.gov (United States)

    Giebułtowicz, Joanna; Kojro, Grzegorz; Piotrowski, Roman; Kułakowski, Piotr; Wroczyński, Piotr

    2016-09-05

    Cloud-point extraction (CPE) is attracting increasing interest in a number of analytical fields, including bioanalysis, as it provides a simple, safe and environmentally-friendly sample preparation technique. However, there are only few reports on the application of this extraction technique in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis. In this study, CPE was used for the isolation of antazoline from human plasma. To date, only one method of antazoline isolation from plasma exists-liquid-liquid extraction (LLE). The aim of this study was to prove the compatibility of CPE and LC-ESI-MS/MS and the applicability of CPE to the determination of antazoline in spiked human plasma and clinical samples. Antazoline was isolated from human plasma using Triton X-114 as a surfactant. Xylometazoline was used as an internal standard. NaOH concentration, temperature and Triton X-114 concentration were optimized. The absolute matrix effect was carefully investigated. All validation experiments met international acceptance criteria and no significant relative matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples. The determination of antazoline concentration in human plasma in the range 10-2500ngmL(-1) by the CPE method led to results which are equivalent to those obtained by the widely used liquid-liquid extraction method.

  12. Qualification Tests of the R11410-21 Photomultiplier Tubes for the XENON1T Detector

    CERN Document Server

    Barrow, P; Cichon, D; Danisch, M; Franco, D; Kaether, F; Kish, A; Lindner, M; Undagoitia, T Marrodan; Mayani, D; Rauch, L; Wei, Y; Wulf, J

    2016-01-01

    The Hamamatsu R11410-21 photomultiplier tube is the photodetector of choice for the XENON1T dual-phase time projection chamber. The device has been optimized for a very low intrinsic radioactivity, a high quantum efficiency and a high sensitivity to single photon detection. A total of 248 tubes are currently operated in XENON1T, selected out of 321 tested units. In this article the procedures implemented to evaluate the large number of tubes prior to their installation in XENON1T are described. The parameter distributions for all tested tubes are shown, with an emphasis on those selected for XENON1T, of which the impact on the detector performance is discussed. All photomultipliers have been tested in a nitrogen atmosphere at cryogenic temperatures, with a subset of the tubes being tested in gaseous and liquid xenon, simulating their operating conditions in the dark matter detector. The performance and evaluation of the tubes in the different environments is reported and the criteria for rejection of PMTs are...

  13. Transportable Xenon Laboratory (TXL-1) Operations Manual

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Robert C.; Stewart, Timothy L.; Willett, Jesse A.; Woods, Vincent T.

    2011-03-07

    The Transportable Xenon Laboratory Operations Manual is a guide to set up and shut down TXL, a fully contained laboratory made up of instruments to identify and measure concentrations of the radioactive isotopes of xenon by taking air samples and analyzing them. The TXL is housed in a standard-sized shipping container. TXL can be shipped to and function in any country in the world.

  14. Xenon recovery from molybdenum-99 production

    Energy Technology Data Exchange (ETDEWEB)

    Jubin, R.T. [Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN, 37931 (United States); Paviet, P.D.; Bresee, J.C. [U.S. Department of Energy,1000 Independence Ave, S.W., Washington DC, 20585-1290 (United States)

    2016-07-01

    The U.S. Department of Energy Office of Nuclear Energy (DOE-NE) sponsors research and development on the recycle of used commercial nuclear fuel as an option for future nuclear fuel cycles that offers increased use of uranium and thorium resources and a possible reduction in the overall cost of nuclear waste management. The two alternatives, direct disposal of used fuel and fuel recycle, are broadly referred to as open and closed fuel cycles. One requirement of a closed fuel cycle is the safe management of radioactive off-gases, which includes {sup 14}C, radioiodine and the noble gases, including radio-xenon. The longest lived relevant radio-xenon isotope is {sup 127}Xe; with a half-life of just 36.35 days it is feasible to trap and hold the radio-xenon to allow for decay to safe environmental levels. However, the very weak chemical bonds of noble gases, in this case xenon, make them difficult to trap, which led to an extensive DOE-NE study of noble gas adsorption on various molecular sieves as an alternative to costly cryogenics processes. Preliminary results indicate that xenon adsorption at near room temperature on molecular sieves, both synthetic and natural, may have both cost and efficiency advantages over cryogenic processes. These results appear to have direct application in helping achieve the United Nations Security Council goal of reducing xenon emissions from medical isotope producers.

  15. Quantitative characterization of solid epoxy resins using comprehensive two dimensional liquid chromatography coupled with electrospray ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Julka, Samir; Cortes, Hernan; Harfmann, Robert; Bell, Bruce; Schweizer-Theobaldt, Andreas; Pursch, Matthias; Mondello, Luigi; Maynard, Shawn; West, David

    2009-06-01

    A comprehensive multidimensional liquid chromatography system coupled to Electrospray Ionization-Mass Spectrometry (LCxLC-ESI-MS) was developed for detailed characterization and quantitation of solid epoxy resin components. The two orthogonal modes of separation selected were size exclusion chromatography (SEC) in the first dimension and liquid chromatography at critical conditions (LCCC) in the second dimension. Different components present in the solid epoxy resins were separated and quantitated for the first time based on the functional groups and molecular weight heterogeneity. Coupling LCxLC separations with mass spectrometry enabled the identification of components resolved in the two-dimensional space. Several different functional group families of compounds were separated and identified, including epoxy-epoxy and epoxy-alpha-glycol functional oligomers, and their individual molecular weight ranges were determined. Repeatability obtained ranged from 0.5% for the main product to 21% for oligomers at the 0.4% concentration level.

  16. Topological signature in the NEXT high pressure xenon TPC

    CERN Document Server

    ,

    2016-01-01

    The NEXT experiment aims to observe the neutrinoless double beta decay of Xe-136 in a high-pressure xenon gas TPC using electroluminescence to amplify the signal from ionization. One of the main advantages of this technology is the possibility to use the topology of events with energies close to Qbb as an extra tool to reject background. In these proceedings we show with data from prototypes that an extra background rejection factor of 24.3 +- 1.4 (stat.)% can be achieved, while maintaining an efficiency of 66.7 +- 1.% for signal events. The performance expected in NEW, the next stage of the experiment, is to improve to 12.9% +- 0.6% background acceptance for 66.9% +- 0.6% signal efficiency.

  17. Subunit analysis of bovine heart complex I by reversed-phase high-performance liquid chromatography, electrospray ionization-tandem mass spectrometry, and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.

    Science.gov (United States)

    Lemma-Gray, Patrizia; Valusová, Eva; Carroll, Christopher A; Weintraub, Susan T; Musatov, Andrej; Robinson, Neal C

    2008-11-15

    An effective method was developed for isolation and analysis of bovine heart complex I subunits. The method uses C18 reversed-phase high-performance liquid chromatography (HPLC) and a water/acetonitrile gradient containing 0.1% trifluoroacetic acid. Employing this system, 36 of the 45 complex I subunits elute in 28 distinct chromatographic peaks. The 9 subunits that do not elute are B14.7, MLRQ, and the 7 mitochondrial-encoded subunits. The method, with ultraviolet (UV) detection, is suitable for either analytical (250 microg protein) applications. Subunits eluting in each chromatographic peak were initially determined by matrix-assisted laser desorption/ionization-time-of-flight/mass spectrometry (MALDI-TOF/MS) with subsequent positive identification by reversed-phase HPLC-electrospray ionization (ESI)/tandem mass spectrometry (MS/MS) analysis of tryptic digests. In the latter case, subunits were identified with a 99% probability using Mascot for database searching and Scaffold for assessment of protein identification probabilities. The reversed-phase HPLC subunit analysis method represents a major improvement over previous separation methods with respect to resolution, simplicity, and ease of application.

  18. Correlation of skin blanching and percutaneous absorption for glucocorticoid receptor agonists by matrix-assisted laser desorption ionization mass spectrometry imaging and liquid extraction surface analysis with nanoelectrospray ionization mass spectrometry.

    Science.gov (United States)

    Marshall, Peter; Toteu-Djomte, Valerie; Bareille, Philippe; Perry, Hayley; Brown, Gillian; Baumert, Mark; Biggadike, Keith

    2010-09-15

    Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) and liquid extraction surface analysis (LESA) with nanoelectrospray ionization mass spectrometry (nESI-MS) have both been successfully employed to determine the degree of percutaneous absorption of three novel nonsteroid glucocorticoid receptor (GR) agonists in porcine ear sections. Historically, the ability of a glucocorticoid to elicit a skin blanching response when applied at low dose in ethanol solution to the forearms of healthy human volunteers has been a reliable predictor of their topical anti-inflammatory activity. While all three nonsteroidal GR agonists under investigation caused a skin blanching effect, the responses did not correlate with in vitro GR agonist potencies and different time courses were also observed for the skin blanching responses. MALDI MSI and LESA with nESI-MS were used to investigate and understand these different responses. The findings of the investigation was that the depth of porcine skin penetration correlates to the degree of skin blanching obtained for the same three compounds in human volunteers.

  19. Simultaneous ionization and analysis of 84 anabolic androgenic steroids in human urine using liquid chromatography-silver ion coordination ionspray/triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Kim, So-Hee; Cha, Eun-Ju; Lee, Kang Mi; Kim, Ho Jun; Kwon, Oh-Seung; Lee, Jaeick

    2014-01-01

    Metal ion coordination ionspray (M(+) CIS) ionization is a powerful technique to enhance ionization efficiency and sensitivity. In this study, we developed and validated an analytical method for simultaneous ionization and analysis of 84 anabolic androgenic steroids (65 exogenous and 19 endogenous) using liquid chromatography-silver ion coordination ionspray/triple-quadrupole mass spectrometry (LC-Ag(+) CIS/MS/MS). The concentrations of silver ions and organic solvents have been optimized to increase the amount of silver ion coordinated complexes. A combination of 25 μM of silver ions and methanol showed the best sensitivity. The validation results showed the intra- (0.8-9.2%) and inter-day (2.5-14.9%) precisions, limits of detection (0.0005-5.0 ng/mL), and matrix effect (71.8-100.3%) for the screening analysis. No significant ion suppression was observed. In addition, this method was successfully applied to analysis of positive samples from suspected abusers and useful for the detection of the trace levels of anabolic steroids in human urine samples.

  20. Reversed phase liquid chromatography hyphenated to continuous flow-extractive desorption electrospray ionization-mass spectrometry for analysis and charge state manipulation of undigested proteins.

    Science.gov (United States)

    Li, Li; Yang, Samuel H; Vidova, Veronika; Rice, Elisa M; Wijeratne, Aruna B; Havlíček, Vladimír; Schug, Kevin A

    2015-01-01

    The application of continuous flow-extractive desorption electrospray ionization (CF-EDESI), an ambient ionization source demonstrated previously for use with intact protein analysis, is expanded here for the coupling of reversed phase protein separations to mass spectrometry. This configuration allows the introduction of charging additives to enhance detection without affecting the chromatographic separation mechanism. Two demonstrations of the advantages of CF-EDESI are presented in this work. First, a proof-of- principle is presented to demonstrate the applicability of hyphenation of liquid chromatography (LC) to CF- EDESI. LC-CF-EDESI-MS has good sensitivity compared to LC-electrospray ionization (ESI)-mass spectrometry. Second, the supercharging mechanism investigated in CF-EDESI provides an insight into a highly debated supercharging process in ESI. The results indicate that the mechanism of protein charging seen in HPLC-CF-EDESI is different from supercharging phenomena in conventional ESI. The surface tension mechanism and binding mechanism may both contribute to protein supercharging in ESI.

  1. Differentiation of cyclosporin A from isocyclosporin A by liquid chromatography/electrospray ionization mass spectrometry with post-column addition of divalent metal salt.

    Science.gov (United States)

    Cirigliano, Adriana M; Cabrera, Gabriela M

    2014-03-15

    Cyclosporin A (CsA) rearranges to its isomer isocyclosporin A (isoCsA) upon acid hydrolysis and also during ionization in the ion source of the mass spectrometer. It has been reported that both compounds could not be differentiated by tandem mass spectrometry (MS/MS) using atmospheric pressure ionization (API) sources and ambiguously differentiated by using other sources. In order to analyze these compounds which are common fungal metabolites, it is relevant to develop a simple method for their differentiation. CsA and isoCsA were analyzed by liquid chromatography/mass spectrometry (LC/MS) with post-column addition of metal ion solutions in a quadrupole time-of-flight instrument equipped with an electrospray ionization (ESI) source. Mass spectra of CsA obtained upon post-column addition of solutions of Ca(II), Cu(II) and Zn(II) showed complexes between cyclosporin and the metal, including [2CsA + Me](2+) and [CsA-H + Me](+). These complexes were not observed in the spectra of isoCsA. The same results were observed at different metal concentrations. Differentiation via metal complexation in positive ion mode LC/ESI-MS was performed to simultaneously distinguish CsA and its isomer isoCsA. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Investigating ion recombination effects in a liquid-filled ionization chamber array used for IMRT QA measurements.

    Science.gov (United States)

    Knill, Cory; Snyder, Michael; Rakowski, Joseph T; Zhuang, Ling; Matuszak, Martha; Burmeister, Jay

    2016-05-01

    PTW's Octavius 1000 SRS array performs IMRT quality assurance (QA) measurements with liquid-filled ionization chambers (LICs) to allow closer detector spacing and higher resolution, compared to air-filled QA devices. However, reduced ion mobility in LICs relative to air leads to increased ion recombination effects and reduced collection efficiencies that are dependent on Linac pulse frequency and pulse dose. These pulse parameters are variable during an IMRT delivery, which affects QA results. In this study, (1) 1000 SRS collection efficiencies were measured as a function of pulse frequency and pulse dose, (2) two methods were developed to correct changes in collection efficiencies during IMRT QA measurements, and the effects of these corrections on QA pass rates were compared. To obtain collection efficiencies, the OCTAVIUS 1000 SRS was used to measure open fields of varying pulse frequency, pulse dose, and beam energy with results normalized to air-filled chamber measurements. Changes in ratios of 1000 SRS to chamber measured dose were attributed to changing collection efficiencies, which were then correlated to pulse parameters using regression analysis. The usefulness of the derived corrections was then evaluated using 6 MV and 10FFF SBRT RapidArc plans delivered to the OCTAVIUS 4D system using a TrueBeam (Varian Medical Systems) linear accelerator equipped with a high definition multileaf collimator. For the first correction, matlab software was developed that calculates pulse frequency and pulse dose for each detector, using measurement and DICOM RT Plan files. Pulse information is converted to collection efficiency, and measurements are corrected by multiplying detector dose by ratios of calibration to measured collection efficiencies. For the second correction the MU/min in the daily 1000 SRS calibration was chosen to match the average MU/min of the volumetric modulated arc therapy plan. Effects of the two corrections on QA results were examined by

  3. Investigating ion recombination effects in a liquid-filled ionization chamber array used for IMRT QA measurements

    Energy Technology Data Exchange (ETDEWEB)

    Knill, Cory, E-mail: knillcor@gmail.com; Snyder, Michael; Rakowski, Joseph T.; Burmeister, Jay [Department of Radiation Oncology, Karmanos Cancer Institute, Detroit, Michigan 48201 and Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States); Zhuang, Ling [Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States); Matuszak, Martha [Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, Michigan 48109 (United States)

    2016-05-15

    Purpose: PTW’s Octavius 1000 SRS array performs IMRT quality assurance (QA) measurements with liquid-filled ionization chambers (LICs) to allow closer detector spacing and higher resolution, compared to air-filled QA devices. However, reduced ion mobility in LICs relative to air leads to increased ion recombination effects and reduced collection efficiencies that are dependent on Linac pulse frequency and pulse dose. These pulse parameters are variable during an IMRT delivery, which affects QA results. In this study, (1) 1000 SRS collection efficiencies were measured as a function of pulse frequency and pulse dose, (2) two methods were developed to correct changes in collection efficiencies during IMRT QA measurements, and the effects of these corrections on QA pass rates were compared. Methods: To obtain collection efficiencies, the OCTAVIUS 1000 SRS was used to measure open fields of varying pulse frequency, pulse dose, and beam energy with results normalized to air-filled chamber measurements. Changes in ratios of 1000 SRS to chamber measured dose were attributed to changing collection efficiencies, which were then correlated to pulse parameters using regression analysis. The usefulness of the derived corrections was then evaluated using 6 MV and 10FFF SBRT RapidArc plans delivered to the OCTAVIUS 4D system using a TrueBeam (Varian Medical Systems) linear accelerator equipped with a high definition multileaf collimator. For the first correction, MATLAB software was developed that calculates pulse frequency and pulse dose for each detector, using measurement and DICOM RT Plan files. Pulse information is converted to collection efficiency, and measurements are corrected by multiplying detector dose by ratios of calibration to measured collection efficiencies. For the second correction the MU/min in the daily 1000 SRS calibration was chosen to match the average MU/min of the volumetric modulated arc therapy plan. Effects of the two corrections on QA results were

  4. Pulse Rise Time Characterization of a High Pressure Xenon Gamma Detector for use in Resolution Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    TROYER, G.L.

    2000-08-25

    High pressure xenon ionization chamber detectors are possible alternatives to traditional thallium doped sodium iodide (NaI(Tl)) and hyperpure germanium as gamma spectrometers in certain applications. Xenon detectors incorporating a Frisch grid exhibit energy resolutions comparable to cadmium/zinc/telluride (CZT) (e.g. 2% {at} 662keV) but with far greater sensitive volumes. The Frisch grid reduces the position dependence of the anode pulse risetimes, but it also increases the detector vibration sensitivity, anode capacitance, voltage requirements and mechanical complexity. We have been investigating the possibility of eliminating the grid electrode in high-pressure xenon detectors and preserving the high energy resolution using electronic risetime compensation methods. A two-electrode cylindrical high pressure xenon gamma detector coupled to time-to-amplitude conversion electronics was used to characterize the pulse rise time of deposited gamma photons. Time discrimination was used to characterize the pulse rise time versus photo peak position and resolution. These data were collected to investigate the effect of pulse rise time compensation on resolution and efficiency.

  5. Separation of polar mushroom toxins by mixed-mode hydrophilic and ionic interaction liquid chromatography-electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Chung, Wai-cheung; Tso, Sau-ching; Sze, Sai-tim

    2007-02-01

    Reversed-phase liquid chromatography (RPLC) is commonly used to analyze nonvolatile contaminants and naturally occurring toxins in foods. However, polar compounds, such as hydrophilic polypeptides and quaternary ammonium salts, are often not satisfactorily separated by RPLC and present a challenge for analytical scientists. In this study, hydrophilic interaction liquid chromatography (HILIC), on an amide-based stationary phase in combination with electrospray ionization (ESI) tandem mass spectrometry (MS-MS), is successfully employed to simultaneously separate polar mushroom toxins, including amanitins and phallotoxins, which are cyclic oligopeptides and muscarine, a quaternary ammonium compound, in mushrooms. The sensitivity of different ionization modes is studied, and the positive ionization mode is found to provide a more sensitive and effective tool for the unambiguous identification of the concerned polar toxins because of their characteristic fragmentation patterns. The properties of the mobile phase are also found to have significant impacts on the separation. At a high acetonitrile (ACN) concentration, hydrophilic interaction dominates, and all analytes under study demonstrate a much higher affinity with the stationary phase. The addition of methanol (MeOH) as a modifier could further enhance the HILIC separation for amanitins, phallotoxins, and muscarine. Valley-to-valley separation is achieved upon the optimatizatiqn of the mobile phase (comprising of ACN, MeOH, and ammonium formate buffer at pH approximately 3.5) and the solvent gradient. HILIC coupled with ESI-MS-MS is demonstrated to be a novel technique for the simultaneous separation and confirmatory analysis of the concerned polar toxins by providing an environment of solubility and retention that could not be achieved through the use of RPLC.

  6. Simultaneous testing of multiclass organic contaminants in food and environment by liquid chromatography/dielectric barrier discharge ionization-mass spectrometry.

    Science.gov (United States)

    Gilbert-López, Bienvenida; García-Reyes, Juan F; Meyer, Cordula; Michels, Antje; Franzke, Joachim; Molina-Díaz, Antonio; Hayen, Heiko

    2012-11-21

    A Dielectric Barrier Discharge Ionization (DBDI) LC/MS interface is based on the use of a low-temperature helium plasma, which features the possibility of simultaneous ionization of species with a wide variety of physicochemical properties. In this work, the performance of LC/DBDI-MS for trace analysis of highly relevant species in food and environment has been examined. Over 75 relevant species including multiclass priority organic contaminants and residues such as pesticides, polycyclic aromatic hydrocarbons, organochlorine species, pharmaceuticals, personal care products, and drugs of abuse were tested. LC/DBDI-MS performance for this application was assessed and compared with standard LC/MS sources (electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI)). The used benchtop Orbitrap mass spectrometer features a 10 Hz polarity switching mode, so that both positive and negative ion mode acquisitions are possible with acquisition cycles matching the requirements of fast liquid chromatography. Both polar and nonpolar species (including those typically analyzed by GC/electron ionization-MS) can be tested in a single run using polarity switching mode. The methodology was found to be effective in detecting a wide array of organic compounds at concentration levels in the low ng L(-1) to μg kg(-1) range in wastewater and food matrices, respectively. The linearity was evaluated in an olive oil extract, obtaining good correlation coefficients in the studied range. Additionally, minor matrix effects (≤15% of signal suppression or enhancement) were observed for most of the studied analytes in this complex fatty matrix. The results obtained were compared with data from both ESI and APCI sources, obtaining a merged coverage between ESI and APCI in terms of analyte ionization and higher overall sensitivity for the proposed ion source based on the DBD principle. The use of this approach further extends the coverage of current LC/MS methods towards

  7. Liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source for elemental mass spectrometry: preliminary parametric evaluation and figures of merit.

    Science.gov (United States)

    Quarles, C Derrick; Carado, Anthony J; Barinaga, Charles J; Koppenaal, David W; Marcus, R Kenneth

    2012-01-01

    A new, low-power ionization source for the elemental analysis of aqueous solutions has recently been described. The liquid sampling-atmospheric pressure glow discharge (LS-APGD) source operates at relatively low currents (LS-APGD has been interfaced to what is otherwise an organic, LC-MS mass analyzer, the Thermo Scientific Exactive Orbitrap without any modifications, other than removing the electrospray ionization source supplied with that instrument. A glow discharge is initiated between the surface of the test solution exiting a glass capillary and a metallic counter electrode mounted at a 90° angle and separated by a distance of ~5 mm. As with any plasma-based ionization source, there are key discharge operation and ion sampling parameters that affect the intensity and composition of the derived mass spectra, including signal-to-background ratios. We describe here a preliminary parametric evaluation of the roles of discharge current, solution flow rate, argon sheath gas flow rate, and ion sampling distance as they apply on this mass analyzer system. A cursive evaluation of potential matrix effects due to the presence of easily ionized elements indicate that sodium concentrations of up to 50 μg mL(-1) generally cause suppressions of less than 50%, dependant upon the analyte species. Based on the results of this series of studies, preliminary limits of detection (LOD) have been established through the generation of calibration functions. While solution-based concentration LOD levels of 0.02-2 μg mL(-1) are not impressive on the surface, the fact that they are determined via discrete 5 μL injections leads to mass-based detection limits at picogram to single-nanogram levels. The overhead costs associated with source operation (10 W d.c. power, solution flow rates of LS-APGD ion source may present a practical alternative to inductively coupled plasma sources typically employed in elemental mass spectrometry.

  8. Comparison of electrospray ionization and atmospheric pressure chemical ionization for multi-residue analysis of biocides, UV-filters and benzothiazoles in aqueous matrices and activated sludge by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wick, Arne; Fink, Guido; Ternes, Thomas A

    2010-04-02

    This paper describes the development of a multi-residue method for the determination of 36 emerging organic pollutants (26 biocides, 5 UV-filters and 5 benzothiazoles) in raw and treated wastewater, activated sludge and surface water using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The target analytes were enriched from water samples adjusted to pH 6 by solid-phase extraction (SPE) on Oasis HLB 200mg cartridges and eluted with a mixture of methanol and acetone (60/40, v/v). Extraction of freeze-dried sludge samples was accomplished by pressurized liquid extraction (PLE) using a mixture of methanol and water (50/50, v/v) as extraction solvent followed by SPE. LC-tandem MS detection was compared using electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in positive and negative ionization mode. ESI exhibited strong ion suppression for most target analytes, while APCI was generally less susceptible to ion suppression but partially leading to ion enhancement of up to a factor of 10. In general, matrix effects could be compensated using stable isotope-labeled surrogate standards, indicated by relative recoveries ranging from 70% to 130%. In wastewater, activated sludge and surface water up to 33 analytes were detected. Maximum concentrations up to 5.1 and 3.9mugL(-1) were found in raw wastewater for the water-soluble UV-filters benzophenone-4 (BZP-4) and phenylbenz-imidazole sulfonic acid (PBSA), respectively. For the first time, the anti-dandruff climbazole was detected in raw wastewater and in activated sludge with concentrations as high as 1.4 microg L(-1) and 1.2 microg gTSS(-1), respectively. Activated sludge is obviously a sink for four benzothiazoles and two isothiazolones, as concentrations were detected in activated sludge between 120 ng gTSS(-1) (2-n-octyl-4-isothiazolin-3-one, OIT) to 330 ng gTSS(-1) (benzothiazole-2-sulfonic acid, BTSA). Copyright (c) 2010 Elsevier B.V. All rights reserved.

  9. Reflectance dependence of polytetrafluoroethylene on thickness for xenon scintillation light

    CERN Document Server

    Haefner, Jonathan; Arthurs, Maris; Batista, Elizabeth; Morton, Daniel; Okunawo, Matt; Pushkin, Kirill; Sander, Aaron; Wang, Yuhan; Lorenzon, Wolfgang

    2016-01-01

    Many rare event searches including dark matter direct detection and neutrinoless double beta decay experiments take advantage of the high VUV reflective surfaces made from polytetrafluoroethylene (PTFE) reflector materials to achieve high light collection efficiency in their detectors. As the detectors have grown in size over the past decade, there has also been an increased need for ever thinner detector walls without significant loss in reflectance to reduce dead volumes around active noble liquids, outgassing, and potential backgrounds. We report on the experimental results to measure the dependence of the reflectance on thickness of two PTFE samples at wavelengths near 178 nm. No change in reflectance was observed as the thickness of a cylindrically shaped PTFE vessel immersed in liquid xenon was varied between 1 mm to 9.5 mm.

  10. Quantitation of triacylglycerols in edible oils by off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column.

    Science.gov (United States)

    Wei, Fang; Hu, Na; Lv, Xin; Dong, Xu-Yan; Chen, Hong

    2015-07-24

    In this investigation, off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column has been applied for the identification and quantification of triacylglycerols in edible oils. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this off-line two-dimensional separation system. The phenyl-hexyl column combined the features of traditional C18 and silver-ion columns, which could provide hydrophobic interactions with triacylglycerols under acetonitrile conditions and can offer π-π interactions with triacylglycerols under methanol conditions. When compared with traditional off-line comprehensive two-dimensional liquid chromatography employing two different chromatographic columns (C18 and silver-ion column) and using elution solvents comprised of two phases (reversed-phase/normal-phase) for triacylglycerols separation, the novel off-line comprehensive two-dimensional liquid chromatography using a single column can be achieved by simply altering the mobile phase between acetonitrile and methanol, which exhibited a much higher selectivity for the separation of triacylglycerols with great efficiency and rapid speed. In addition, an approach based on the use of response factor with atmospheric pressure chemical ionization mass spectrometry has been developed for triacylglycerols quantification. Due to the differences between saturated and unsaturated acyl chains, the use of response factors significantly improves the quantitation of triacylglycerols. This two-dimensional liquid chromatography-mass spectrometry system was successfully applied for the profiling of triacylglycerols in soybean oils, peanut oils and lord oils. A total of 68 triacylglycerols including 40 triacylglycerols in soybean oils, 50 triacylglycerols in peanut oils and 44 triacylglycerols in lord oils have been identified and quantified. The liquid chromatography-mass spectrometry data were analyzed

  11. Reflectance measurements of PTFE, Kapton, and PEEK for xenon scintillation light for the LZ detector.

    Science.gov (United States)

    Arthurs, M.; Batista, E.; Haefner, J.; Lorenzon, W.; Morton, D.; Neff, A.; Okunawo, M.; Pushkin, K.; Sander, A.; Stephenson, S.; Wang, Y.; LZ Collaboration

    2017-01-01

    LZ (LUX-Zeplin) is an international collaboration that will look for dark matter candidates, WIMPs (Weakly Interacting Massive Particles), through direct detection by dual-phase time projection chamber (TPC) using liquid xenon. The LZ detector will be located nearly a mile underground at SURF, South Dakota, shielded from cosmic background radiation. Seven tons active mass of liquid xenon will be used for detecting the weak interaction of WIMPs with ordinary matter. Over three years of operation it is expected to reach the ultimate sensitivity of 2x10-48 cm2 for a WIMP mass of 50 GeV. As for many other rare event searches, high light collection efficiency is essential for LZ detector. Moreover, in order to achieve greater active volume for detection as well as reduce potential backgrounds, thinner detector walls without significant loss in reflectance are desired. Reflectance measurements of polytetrafluoroethylene (PTFE), Kapton, and PEEK for xenon scintillation light (178 nm), conducted at the University of Michigan using the Michigan Xenon Detector (MiX) will be presented. The University of Michigan, LZ Collaboration, The US Department of Energy.

  12. Atmospheric pressure laser desorption/ionization using a 6-7 µm-band mid-infrared tunable laser and liquid water matrix.

    Science.gov (United States)

    Hiraguchi, Ryuji; Hazama, Hisanao; Masuda, Katsuyoshi; Awazu, Kunio

    2015-01-01

    Due to the characteristic absorption peaks in the IR region, various molecules can be used as a matrix for infrared matrix-assisted laser desorption/ionization (IR-MALDI). Especially in the 6-7 µm-band IR region, solvents used as the mobile phase for liquid chromatography have absorption peaks that correspond to their functional groups, such as O-H, C=O, and CH3. Additionally, atmospheric pressure (AP) IR-MALDI, which is applicable to liquid-state samples, is a promising technique to directly analyze untreated samples. Herein we perform AP-IR-MALDI mass spectrometry of a peptide, angiotensin II, using a mid-IR tunable laser with a tunable wavelength range of 5.50-10.00 µm and several different matrices. The wavelength dependences of the ion signal intensity of [M + H](+) of the peptide are measured using a conventional solid matrix, α-cyano-4-hydroxycinnamic acid (CHCA) and a liquid matrix composed of CHCA and 3-aminoquinoline. Other than the O-H stretching and bending vibration modes, the characteristic absorption peaks are useful for AP-IR-MALDI. Peptide ions are also observed from an aqueous solution of the peptide without an additional matrix, and the highest peak intensity of [M + H](+) is at 6.00 µm, which is somewhat shorter than the absorption peak wavelength of liquid water corresponding to the O-H bending vibration mode. Moreover, long-lasting and stable ion signals are obtained from the aqueous solution. AP-IR-MALDI using a 6-7 µm-band IR tunable laser and solvents as the matrix may provide a novel on-line interface between liquid chromatography and mass spectrometry.

  13. XENON ANESTHESIA IN CHILDREN: BIS-MONITORING

    Directory of Open Access Journals (Sweden)

    V. G. Bagaev

    2013-01-01

    Full Text Available We conducted 60 low-flow xenon anesthesias in children of 1-18 years of age. We measured the sedation level using bispectral (BIS index and clinically on the stage of induction, xenon anesthesia maintenance and during recovery. The trial showed that, according to the clinical and BIS-monitoring data, sevoflurane inhalational induction in children of 1-5 years of age and propofol intravenous induction in children of 6-18 years of age provides children with the required sedation level. BIS index objectively reflects intensity of the sedative component of an anesthesia both in the junior and the senior age groups on the stages of xenon anesthesia maintenance and during recovery.

  14. A study of the electron image due to ionizing events in a two-dimensional liquid argon TPC with a 24 cm drift gap

    Science.gov (United States)

    Bonetti, S.; Braggiotti, A.; Buckley, E.; Campanella, M.; Carugno, G.; Cecchet, G.; Cennini, P.; Centro, S.; Ciocio, A.; Cittolin, S.; Dainese, B.; Ferro-Luzzi, M.; Gasparini, F.; Gonidec, A.; Manfredi, P. F.; Meroni, E.; Muñoz, R.; Perreau, J.-M.; Pietropaolo, F.; Ptohos, F.; Ragusa, F.; Rossi, P.; Rubbia, C.; Schinzel, D.; Schmidt, W. F.; Seidl, W.

    1990-01-01

    We have tested a liquid argon time projection chamber with a novel wire configuration based on electrostatic focussing which allows the realization of a nondestructive detection of the electron image produced by ionizing events. The chamber was tested in a 5 GeV pion beam at the CERN proton synchrotron. The measured pulse shapes at both 200 V/cm and 500 V/cm were in very good agreement with the expected shapes, calculated taking into account the electron lifetime, the response of the electronics and the longitudinal diffusion of the electron cloud. The measured electron drift velocity was in good agreement with the results of other workers as well as with our previous measurements. We have also analysed a sample of events containing delta rays in order to study the behaviour of low-energy electrons in the liquid argon. We find that for electron energies greater than 5 MeV the measured energy spectrum agrees very well with the predicted spectrum after corrections for acceptance and energy loss, hence demonstrating the feasibility of recognizing low-energy electrons in liquid argon.

  15. Rapid identification of erythrocyte phospholipids in Sprague-Dawley rats by ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Pi, Juanjuan; Wu, Xia; Yang, Shitian; Zeng, Pingyan; Feng, Yifan

    2015-03-01

    A rapid, sensitive, and reliable approach for analyzing five kinds of erythrocyte phospholipids in Sprague-Dawley rats was provided by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry with MassLynx(TM) MassFragment. Improving conventional high performance liquid chromatography techniques, ultra high performance liquid chromatography integrated with quadrupole time-of-flight tandem mass spectrometry offers high sensitivity and increased analytical speed by using columns packed with sub-2 μm particles (1.7 μm), which allows a faster separation to be achieved. Through this method, 83 phospholipids were tentatively characterized based on their mass spectra and tandem mass spectra, as well as by matching the in-house formula database within a mass error of 5 ppm, including 40 phosphatidylcholines, 24 phosphatidyl ethanolamines, three phosphatidylinositols, six phosphatidylserines, and ten sphingomyelins. Our present results proved that the established method could be used to qualitatively analyze complex erythrocyte phospholipids in Sprague-Dawley rats and provide a useful data base for pharmacology and phospholipidomics to seek potential biomarkers of disease prediction.

  16. Qualitative characterization of Desmodium adscendens constituents by high-performance liquid chromatography-diode array ultraviolet-electrospray ionization multistage mass spectrometry.

    Science.gov (United States)

    Baiocchi, Claudio; Medana, Claudio; Giancotti, Valeria; Aigotti, Riccardo; Dal Bello, Frederica; Massolino, Cristina; Gastaldi, Daniela; Grandi, Maurizio

    2013-01-01

    The many effects of the African medicinal herb Desmodium adscendens were studied in the 1980s and 1990s. In spite of this, a comprehensive analytical protocol for the quality control of its constituents (soyasaponins, alkaloids and flavonoids) has not yet been formulated and reported. This study deals with the optimization of extraction conditions from the plant and qualitative identification of the constituents by HPLC-diode array UV and multistage mass spectrometry. Plant constituents were extracted from leaves by liquid-liquid and solid matrix dispersion extraction. Separation was achieved via RP-C18 liquid chromatographywith UV and MS(n) detection and mass spectrometry analysis was conducted by electrospray ionization ion trap or orbitrap mass spectrometry. High resolution mass spectrometry (HRMS) was used for structural identification of active molecules relating to soyasaponins and alkaloids. The flavonoid fragmentations were preliminarily studied by HRMS in order to accurately characterize the more common neutral losses. However, the high number of isomeric species induced us to make recourse to a more extended chromatographic separation in order to enable useful tandem mass spectrometry and ultraviolet spectral interpretation to propose a reasonable chemical classification of these polyphenols. 35 compounds of this class were identified herein with respect to the five reported in literature in this way we made up a comprehensive protocol for the qualitative analysis of the high complexity content of this plant. This result paves the way for both reliable quality control of potential phytochemical medicaments and possible future systematic clinical studies.

  17. Determination of alprostadil in rat plasma by ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry after intravenous administration.

    Science.gov (United States)

    Lin, Xia; Zhang, Yu; Cui, Yue; Wang, Lin; Wang, Jing; Tang, Xing

    2009-05-01

    A rapid, highly selective ultra performance liquid chromatography-electrospray ionisation-tandem mass spectrometry method (UPLC-ESI-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of alprostadil in rat plasma. After a simple sample preparation procedure involving a one-step liquid-liquid extraction, alprostadil and the internal standard, diphenhydramine, were chromatographed on an ACQUITY UPLC BEH C(18) column with gradient elution using a mobile phase consisting of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.25 mL min(-1). The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode via an electrospray ionization (ESI) source. The calibration curve was linear (r(2)=0.99) over the concentration range 0.4-250.0 ng mL(-1), with a lower limit of quantification of 0.4 ng mL(-1) for alprostadil. The inter- and intra-day precision (%R.S.D.) was less than 8.5% and 2.4%, respectively, and the accuracy (RE%) was between 9.3% and 1.0% (n=6). Alprostadil in rat plasma was stable when stored at room temperature for 0.5h and at -20 degrees C for two weeks. The method was very rapid, simple and reliable, and was employed for the first time for the pharmacokinetic studies of alprostadil in rats after a single intravenous administration of 50 microg kg(-1).

  18. Antioxidant activity guided separation of major polyphenols of marjoram (Origanum majorana L.) using flash chromatography and their identification by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Hossain, Mohammad B; Camphuis, Gabriel; Aguiló-Aguayo, Ingrid; Gangopadhyay, Nirupama; Rai, Dilip K

    2014-11-01

    Marjoram extracts have been separated into polar and nonpolar parts using liquid-liquid extraction. Both polar and nonpolar parts of the extracts were further fractionated by flash chromatography. The obtained fractions (90 polar and 45 nonpolar fractions) were investigated for their antioxidant activities by 2,2-diphenylpicrylhydrazyl and ferric ion reducing antioxidant power assays. A direct, positive, and linear relationship between antioxidant activity and total phenolic content of the fractions was observed. Based on antioxidant and total phenolic content data, the three fractions with the high antioxidant activities from polar and nonpolar part of the extract were analyzed for their constituent polyphenols by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Compounds were identified by matching the mass spectral data and retention time with those of authentic standards. Identification of the compounds for which there were no "in-house" standards available was carried out by accurate mass measurement of the precursor ions and product ions generated from collision-induced dissociation. Rosmarinic acid was found to be the strongest antioxidant polyphenol conferring the highest antioxidant activity to fractions 47 and 17 of polar and nonpolar part of the extract, respectively. The identification of the rosmarinic acid was further confirmed by (1) H NMR spectroscopy.

  19. Ion suppression and enhancement effects of co-eluting analytes in multi-analyte approaches: systematic investigation using ultra-high-performance liquid chromatography/mass spectrometry with atmospheric-pressure chemical ionization or electrospray ionization.

    Science.gov (United States)

    Remane, Daniela; Meyer, Markus R; Wissenbach, Dirk K; Maurer, Hans H

    2010-11-15

    In multi-analyte procedures, sufficient separation is important to avoid interferences, particularly when using liquid chromatography/mass spectrometry (LC/MS) because of possible ion suppression or enhancement. However, even using ultra-high-performance LC, baseline separation is not always possible. For development and validation of an LC/MS/MS approach for quantification of 140 antidepressants, benzodiazepines, neuroleptics, beta-blockers, oral antidiabetics, and analytes measured in the context of brain death diagnosis in plasma, the extent of ion suppression or enhancement of co-eluting analytes within and between the drug classes was investigated using atmospheric-pressure chemical ionization (APCI) or electrospray ionization (ESI). Within the drug classes, five analytes showed ion enhancement of over 25% and six analytes ion suppression of over 25% using APCI and 16 analytes ion suppression of over 25% using ESI. Between the drug classes, two analytes showed ion suppression of over 25% using APCI. Using ESI, one analyte showed ion enhancement of over 25% and five analytes ion suppression of over 25%. These effects may influence the drug quantification using calibrators made in presence of overlapping and thus interfering analytes. Ion suppression/enhancement effects induced by co-eluting drugs of different classes present in the patient sample may also lead to false measurements using class-specific calibrators made in absence of overlapping and thus interfering analytes. In conclusion, ion suppression and enhancement tests are essential during method development and validation in LC/MS/MS multi-analyte procedures, with special regards to co-eluting analytes.

  20. Structural studies of the allelic wheat glutenin subunits 1Bx7 and 1Bx20 by matrix-assisted laser desorption/ionization mass spectrometry and high-performance liquid chromatography/electrospray ionization mass spectrometry.

    Science.gov (United States)

    Cunsolo, Vincenzo; Foti, Salvatore; Saletti, Rosaria; Gilbert, Simon; Tatham, Arthur S; Shewry, Peter R

    2004-01-01

    Structural studies of the high molecular mass (HMM) glutenin subunits 1Bx7 (from cvs Hereward and Galatea) and 1Bx20 (from cv. Bidi17) of bread wheat were conducted using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) and reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (RP-HPLC/ESI-MS). For all three proteins, MALDI-TOFMS analysis showed that the isolated fractions contained a second component with a mass about 650 Da lower than the major component. The testing and correction of the gene-derived amino acid sequences of the three proteins were performed by direct MALDI-TOFMS analysis of their tryptic peptide mixture. Analysis of the digest was performed by recording several MALDI mass spectra of the mixture at low, medium and high mass ranges, optimizing the matrix and the acquisition parameters for each mass range. Complementary data were obtained by RP-HPLC/ESI-MS analysis of the tryptic digest. This resulted in coverage of about 98% of the sequences. In contrast to the gene-derived data, the results obtained demonstrate the insertion of the sequence QPGQGQ between Trp716 and Gln717 of subunit 1Bx7 (cv. Galatea) and a possible single amino acid substitution within the T20 peptide of subunit 1Bx20. Moreover, the mass spectrometric data demonstrated that the lower mass components present in all the fractions correspond to the major components but lack about six amino acid residues, which are probably lost from the protein C-terminus. Finally, the results obtained provide evidence for the lack of glycosylation or other post-translational modifications of these subunits. Copyright 2004 John Wiley & Sons, Ltd.

  1. Diclofenac in municipal wastewater treatment plant: quantification using laser diode thermal desorption--atmospheric pressure chemical ionization--tandem mass spectrometry approach in comparison with an established liquid chromatography-electrospray ionization-tandem mass spectrometry method.

    Science.gov (United States)

    Lonappan, Linson; Pulicharla, Rama; Rouissi, Tarek; Brar, Satinder K; Verma, Mausam; Surampalli, Rao Y; Valero, José R

    2016-02-12

    Diclofenac (DCF), a prevalent non-steroidal anti-inflammatory drug (NSAID) is often detected in wastewater and surface water. Analysis of the pharmaceuticals in complex matrices is often laden with challenges. In this study a reliable, rapid and sensitive method based on laser diode thermal desorption/atmospheric pressure chemical ionization (LDTD/APCI) coupled with tandem mass spectrometry (MS/MS) has been developed for the quantification of DCF in wastewater and wastewater sludge. An established conventional LC-ESI-MS/MS (liquid chromatography-electrospray ionization-tandem mass spectrometry) method was compared with LDTD-APCI-MS/MS approach. The newly developed LDTD-APCI-MS/MS method reduced the analysis time to 12s in lieu of 12 min for LC-ESI-MS/MS method. The method detection limits for LDTD-APCI-MS/MS method were found to be 270 ng L(-1) (LOD) and 1000 ng L(-1) (LOQ). Furthermore, two extraction procedures, ultrasonic assisted extraction (USE) and accelerated solvent extraction (ASE) for the extraction of DCF from wastewater sludge were compared and ASE with 95.6 ± 7% recovery was effective over USE with 86 ± 4% recovery. The fate and partitioning of DCF in wastewater (WW) and wastewater sludge (WWS) in wastewater treatment plant was also monitored at various stages of treatment in Quebec Urban community wastewater treatment plant. DCF exhibited affinity towards WW than WWS with a presence about 60% of DCF in WW in contrary with theoretical prediction (LogKow=4.51).

  2. A G/NARRLI Effort. Measuring the Ionization Yield of Low-Energy Nuclear Recoils in Liquid Argon

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Tenzing Henry Yatish [Univ. of California, Berkeley, CA (United States)

    2014-01-01

    Liquid argon has long been used for particle detection due to its attractive drift properties, ample abundance, and reasonable density. The response of liquid argon to lowenergy O(102 -1044 eV) interactions is, however, largely unexplored. Weakly interacting massive particles such as neutrinos and hypothetical dark-matter particles (WIMPs) are predicted to coherently scatter on atomic nuclei, leaving only an isolated low-energy nuclear recoil as evidence. The response of liquid argon to low-energy nuclear recoils must be studied to determine the sensitivity of liquid argon based detectors to these unobserved interactions. Detectors sensitive to coherent neutrino-nucleus scattering may be used to monitor nuclear reactors from a distance, to detect neutrinos from supernova, and to test the predicted behavior of neutrinos. Additionally, direct detection of hypothetical weakly interacting dark matter would be a large step toward understanding the substance that accounts for nearly 27% of the universe. In this dissertation I discuss a small dual-phase (liquid-gas) argon proportional scintillation counter built to study the low-energy regime and several novel calibration and characterization techniques developed to study the response of liquid argon to low-energy O(102 -104 eV) interactions.

  3. 2D simulations of short-pulsed dielectric barrier discharge xenon excimer lamp

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, E.A.; Kudryavtsev, A.A. [St. Petersburg State University, St. Petersburg (Russian Federation); Arslanbekov, R.R. [CFD Research Corporation, Huntsville (United States)

    2006-07-01

    Self-consistent two-dimensional (2D) simulations of short-pulsed dielectric barrier discharge (DBD) in pure xenon have been performed. It is shown that during short current pulse the traversal inhomogeneity of the plasma parameters can be important only at the end of the current pulse as an edge effect close to the side walls. During the current pulse, the gap voltage drops until the ionization wave reaches the cathode so the current in the cathode sheath is the displacement current. This means that almost all of the absorbed power is deposited into excitation of xenon atoms and not to the ion heating in the cathode sheath as in the traditional glow discharges. This fact is one of the reasons of high efficiency of short-pulsed DBD. The developed model allows one to estimate the temporal position of the plasma-sheath boundary. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  4. Reverse-phase liquid chromatography with electrospray ionization/mass spectrometry for the quantification of pseudoephedrine in human plasma and application to a bioequivalence study.

    Science.gov (United States)

    Kim, Jin-Ki; Jee, Jun-Pil; Park, Jeong-Sook; Kim, Hyung Tae; Kim, Chong-Kook

    2011-01-01

    A sensitive and selective reverse-phase liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method was developed and validated to quantify pseudoephedrine (CAS 90-82-4) in human plasma. Phenacetin was used as the internal standard (I.S.). Sample preparation was performed with a deproteinization step using acetonitrile. Pseudoephedrine and I.S. were successfully separated using gradient elution with 0.5% trifluoroacetic acid (TFA) in water and 0.5% TFA in methanol at a flow-rate of 0.2 mL/min. Detection was performed on a single quadrupole mass spectrometer by a selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The ESI source was set at positive ionization mode. The ion signals of m/z 166.3 and 180.2 were measured for the protonated molecular ions of pseudoephedrine and I.S., respectively. The lower limit of quantification (LLOQ) of pseudoephedrine in human plasma was 10 ng/mL and good linearity was observed in the range of concentrations 10-500 ng/mL (R2 = 1). The intra-day accuracy of the drug containing plasma samples was more than 97.60% with a precision of 3.99-11.82%. The inter-day accuracy was 99.36% or more, with a precision of 7.65-18.42%. By using this analytical method, the bioequivalence study of the pseudoephedrine preparation was performed and evaluated by statistical analysis of the log transformed mean ratios of pharmacokinetic parameters. All the results fulfilled the standard criteria of bioequivalence, being within the 80-125% range which is required by the Korea FDA, US FDA, and EMEA to conclude bioequivalence. Consequently, the developed reverse-phase LC-ESI-MS method was successfully applied to bioequivalence studies of pseudoephedrine in healthy male volunteers.

  5. Measurement of scintillation and ionization yield with high-pressure gaseous mixtures of Xe and TMA for improved neutrinoless double beta decay and dark matter searches

    CERN Document Server

    Nakajima, Y; Matis, H S; Miller, T; Nygren, D R; Oliveira, C A B; Renner, J

    2015-01-01

    The gaseous Xenon(Xe) time projection chamber (TPC) is an attractive detector technique for neutrinoless double beta decay and WIMP dark matter searches. While it is less dense compared to Liquid Xe detectors, it has intrinsic advantages in tracking capability and better energy resolution. The performance of gaseous Xe can be further improved by molecular additives such as trimethylamine(TMA), which is expected to (1) cool down the ionization electrons, (2) convert Xe excitation energy to TMA ionizations through Penning transfer, and (3) produce scintillation and electroluminescence light in a more easily detectable wavelength (300 nm). In order to test the feasibility of the performance improvements with TMA, we made the first direct measurement of Penning and fluorescence transfer efficiency with gaseous mixtures of Xe and TMA. While we observed a Penning transfer efficiency up to ~35%, we found strong suppression of primary scintillation light with TMA. We also found that the primary scintillation light wi...

  6. Identification and determination of glycosides in tobacco leaves by liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry.

    Science.gov (United States)

    Pang, Tao; Yuan, Zhongyi; Dai, Yongsheng; Wang, Chang; Yang, Jun; Peng, Liming; Xu, Guowang

    2007-02-01

    HPLC-atmospheric pressure chemical ionization MS (HPLC-APCI-MS) was used to screen and identify glycosides in tobacco leaf. MS/MS and MS3 and photodiode array (PDA) detection were also used in the characterization. A total of 12 glycosides were found and four of them were identified based on their abundant [M + H]+ ions, UV spectra, and MS/MS analysis and they are scopolin, rutin, quercetin-3-glycoside, and kaempferol-3-rutinoside. Analytical characteristics of the method were investigated. The contents of these glycosides were obtained and compared based on the relative peak area to the internal standard in seven kinds of tobacco leaf.

  7. Coal liquefaction process streams characterization and evaluation:. Characterization of coal liquids by field ionization mass spectrometry and iodotrimethylsilane derivatization

    Energy Technology Data Exchange (ETDEWEB)

    Malhotra, R.; McMillen, D.F. [SRI International, Menlo Park, CA (United States); Burke, F.P.; Winschel, R.A.; Brandes, S.D. [Consolidation Coal Co., Library, PA (United States). Research and Development Dept.

    1992-01-01

    SRI International evaluated two analytical methods for application to coal liquefaction. These included field ionization mass spectrometry and a technique employing iodotrimethylsilane for the derivatization of oxygen bound to alkyl carbon (alkyl ethers). The full report authored by the SRI researchers is presented here. The following assessment briefly highlights the major findings of the project, and evaluates the potential of the methods for application to coal-derived materials. These results will be incorporated by Consol into a general overview of the application of novel analytical techniques to coal-derived materials at the conclusion of this contract. (VC)

  8. Comprehensive metabolite profiling of Plantaginis Semen using ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique.

    Science.gov (United States)

    Wang, Dandan; Qi, Meng; Yang, Qiming; Tong, Renchao; Wang, Rui; Bligh, S W Annie; Yang, Li; Wang, Zhengtao

    2016-05-01

    Plantaginis Semen is commonly used in traditional medicine to treat edema, hypertension, and diabetes. The commercially available Plantaginis Semen in China mainly comes from three species. To clarify the chemical composition and distinct different species of Plantaginis Semen, we established a metabolite profiling method based on ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique. A total of 108 compounds, including phenylethanoid glycosides, flavonoids, guanidine derivatives, terpenoids, organic acids, and fatty acids, were identified from Plantago asiatica L., P. depressa Willd., and P. major L. Results showed significant differences in chemical components among the three species, particularly flavonoids. This study is the first to provide a comprehensive chemical profile of Plantaginis Semen, which could be involved into the quality control, medication guide, and developing new drug of Plantago seeds.

  9. Structural elucidation of metabolites of ginkgolic acid in rat liver microsomes by ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry and hydrogen/deuterium exchange.

    Science.gov (United States)

    Liu, Z H; Chen, J; Yu, L S; Jiang, H D; Yao, T W; Zeng, S

    2009-07-01

    Ginkgolic acids have been shown to possess allergenic as well as genotoxic and cytotoxic properties. The question arises whether the metabolism of ginkgolic acids in the liver could decrease or increase their toxicity. In this study, the in vitro metabolism of ginkgolic acid (15:1, GA), one component of ginkgo acids, was investigated as a model compound in Sprague-Dawley rat liver microsomes. The metabolites were analyzed by ultra-performance liquid chromatography coupled with photodiode array detector/negative-ion electrospray ionization tandem mass spectrometry (UPLC-PDA/ESI-MS/MS) and hydrogen/deuterium (H/D) exchange. The result showed that the benzene ring remained unchanged and the oxidations occurred at the side alkyl chain in rat liver microsomes. At least eight metabolites were found. Among them, six phase I metabolites were tentatively identified. This study might be useful for the investigation of toxicological mechanism of ginkgolic acids.

  10. Phenolic Compounds of Pinus brutia Ten.: Chemical Investigation and Quantitative Analysis Using an Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry with Electrospray Ionization Source

    Directory of Open Access Journals (Sweden)

    İbrahim Kıvrak

    2013-08-01

    Full Text Available In this study, phenolic content of Pinus brutia ’s bark was examined using an ultra-performance liquid chromatography tandem mass spectrometry with electrospray ionization source (UPLC-ESI-MS/MS working in multiple reaction monitoring mode. U ltrasonic extraction method with 50% ethanol solution was used for the extraction of bark. The bark of Pinus brutia consisted of 15 compounds: gallic acid, gentisic acid, protocatechuic acid, 4-hydroxy benzoic acid, catechin hydrate, vanillic acid, caffeic acid, vanillin, p-coumaric acid, ferulic acid, myricetin, resveratrol, luteolin, naringenin, kaempferol. Major compound detected was catechin hydrate (28.305 mg 100 g -1 extract. The phenolic compounds of Pinus brutia extract and pycnogenol were compared, and it is shown that both of them consisted of considerable amount of phenolic compounds.

  11. Development and Deployment of a Particle-into-Liquid sampling - Electrospray Ionization Mass Spectrometer (PiLs-ESI/MS) for Characterization of Water-Soluble Biomass Burning Aerosols

    Science.gov (United States)

    Stockwell, C.; Witkowski, B.; Talukdar, R. K.; Middlebrook, A. M.; Roberts, J. M.

    2016-12-01

    Biomass burning (BB) is a major influence on Earth's atmosphere as it is an important source of primary and secondary aerosols. Measuring the aerosol composition for such complex mixtures remains an analytical challenge and the characterization of the water-soluble portion of BB aerosol has been traditionally limited to off-line analysis and/or qualitative techniques. In this work, we present a new method of directly interfacing a particle-into-liquid sampler with an electrospray ionization mass spectrometer (PiLs-ESI/MS). This technique allows real-time, sensitive, and chemically-specific speciation of water-soluble organics and inorganics for the quantification of fresh BB aerosol sampled during the recent Firelab component of the NOAA FIREX experiments. The aerosol composition is fuel and combustion-phase dependent, and several polar organic species thought to be main contributors to aerosol brown carbon and secondary organic aerosol were measured.

  12. Characterization of phenolic acids and flavonoids in dandelion (Taraxacum officinale WEB. ex WIGG.) root and herb by high-performance liquid chromatography/electrospray ionization mass spectrometry.

    Science.gov (United States)

    Schütz, Katrin; Kammerer, Dietmar R; Carle, Reinhold; Schieber, Andreas

    2005-01-01

    Phenolic acids and flavonoids were extracted from a dandelion (Taraxacum officinale WEB. ex WIGG.) root and herb juice and characterized by high-performance liquid chromatography/electrospray ionization mass spectrometry. Among the 43 compounds detected, 5 mono- and dicaffeoylquinic acids, 5 tartaric acid derivatives, 8 flavone and 8 flavonol glycosides were characterized based on their UV spectra and their fragmentation patterns in collision-induced dissociation experiments. The predominant compound was chicoric acid (dicaffeoyltartaric acid). Furthermore, several caffeoylquinic acid isomers were distinguished in dandelion extracts for the first time by their specific mass spectral data. The present study reveals that even more quercetin glycosides were found in dandelion than hitherto assumed. The occurrence of di- and triglycosylated flavonoids in particular has not yet been described. This paper marks the first report on HPLC-DAD/ESI-MSn investigations of phenolic compounds in dandelion.

  13. Extraction and Characterization of Phenolic Compounds from Rose Hip (Rosa canina L. Using Liquid Chromatography Coupled with Electrospray Ionization - Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Andreea STĂNILĂ

    2015-12-01

    Full Text Available Wild berry are a rich of natural compounds which provide them high antioxidant potential. The compounds which provide them these proprieties are known to be vitamins, flavonoids, anthocyanins and phenolic acids. The aim of this study was to extract and characterize bioactive compounds from rose hip (Rosa canina L. currently found in Romania. A qualitative high-performance liquid chromatography coupled with electrospray ionization mass spectrometric (ESI-MS detection in positive ion mode has been used to identify phenolic compounds from rose hip crude extract. The chromatograms revealed the presence of a large number of compounds (19, identified and grouped as phenolic acids and flavones/ols, flavan-3-ols and also anthocyanins. Based on obtained results these berries can be highly recommended as part of our diet. Also this finding represents a contribution to the chemical characterization of phenolic profile of rose hip.

  14. Determination of benzothiazole and benzotriazole derivates in tire and clothing textile samples by high performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Avagyan, Rozanna; Sadiktsis, Ioannis; Thorsén, Gunnar; Östman, Conny; Westerholm, Roger

    2013-09-13

    A high performance liquid chromatography-tandem mass spectrometry method utilizing electrospray ionization in positive and negative mode has been developed for the separation and detection of benzothiazole and benzotriazole derivates. Ultra-sonication assisted solvent extraction of these compounds has also been developed and the overall method demonstrated on a selected clothing textile and an automobile tire sample. Matrix effects and extraction recoveries, as well as linearity and limits of detection have been evaluated. The calibration curves spanned over more than two orders of magnitude with coefficients of correlation R(2)>0.99 and the limits of detection and the limits of quantification were in the range 1.7-58pg injected and 18-140pg/g, respectively. The extraction recoveries ranged between 69% and 102% and the matrix effects between 75% and 101%. Benzothiazole and benzotriazole derivates were determined in the textile sample and benzothiazole derivatives determined in the tire sample with good analytical performance.

  15. Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds

    DEFF Research Database (Denmark)

    Hartvigsen, Karsten; Ravandi, A.; Bukhave, Klaus

    2001-01-01

    A reversed-phase high-performance liquid chromatography (HPLC) method with on-line electrospray ionization/collision-induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were...... characterized by chromatographic retention times, full mass spectra, and fragmentation patterns as an aid to clarify the regiospecificity of ether lipids from natural sources. The results clearly show that single quadrupole mass spectroscopic analysis may elucidate the regiospecific structure of neutral ether...... lipids. Ether lipid reference compounds were characterized by five to six major ions in the positive ion mode. The 1-O-alkyl-sn-glycerols were analyzed as the diacetoyl derivative, and showed the [M - acetoyl](+) ion as an important diagnostic ion. The diagnostic ions of directly analyzed 1-O- alkyl-2...

  16. Determination of torasemide in human plasma and its bioequivalence study by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2016-04-01

    Full Text Available A sensitive and selective method using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC–ESI–MS to determine the concentration of torasemide in human plasma samples was developed and validated. Tolbutamide was chosen as the internal standard (IS. The chromatography was performed on a Gl Sciences Inertsil ODS-3 column (100 mm×2.1 mm i.d., 5.0 µm within 5 min, using methanol with 10 mM ammonium formate (60:40, v/v as mobile phase at a flow rate of 0.2 mL/min. The targeted compound was detected in negative ionization at m/z 347.00 for torasemide and 269.00 for IS. The linearity range of this method was found to be within the concentration range of 1–2500 ng/mL (r=0.9984 for torasemide in human plasma. The accuracy of this measurement was between 94.05% and 103.86%. The extracted recovery efficiency was from 84.20% to 86.47% at three concentration levels. This method was also successfully applied in pharmacokinetics and bioequivalence studies in Chinese volunteers.

  17. Analysis of iodinated haloacetic acids in drinking water by reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry with large volume direct aqueous injection.

    Science.gov (United States)

    Li, Yongtao; Whitaker, Joshua S; McCarty, Christina L

    2012-07-01

    A large volume direct aqueous injection method was developed for the analysis of iodinated haloacetic acids in drinking water by using reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry in the negative ion mode. Both the external and internal standard calibration methods were studied for the analysis of monoiodoacetic acid, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid in drinking water. The use of a divert valve technique for the mobile phase solvent delay, along with isotopically labeled analogs used as internal standards, effectively reduced and compensated for the ionization suppression typically caused by coexisting common inorganic anions. Under the optimized method conditions, the mean absolute and relative recoveries resulting from the replicate fortified deionized water and chlorinated drinking water analyses were 83-107% with a relative standard deviation of 0.7-11.7% and 84-111% with a relative standard deviation of 0.8-12.1%, respectively. The method detection limits resulting from the external and internal standard calibrations, based on seven fortified deionized water replicates, were 0.7-2.3 ng/L and 0.5-1.9 ng/L, respectively.

  18. Simultaneous quantification of 25 active constituents in the total flavonoids extract from Herba Desmodii Styracifolii by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Guo, Panpan; Yan, Wenying; Han, Qingjie; Wang, Chunying; Zhang, Zijian

    2015-04-01

    A sensitive and selective high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry method has been developed and validated for the simultaneous determination of 25 active constituents, including 21 flavonoids and four phenolic acids in the total flavonoids extract from Herba Desmodii Styracifolii for the first time. Among the 25 compounds, seven compounds including caffeic acid, acacetin, genistein, genistin, diosmetin, diosmin and hesperidin were identified and quantified for the first time in Herba Desmodii Styracifolii. Chromatographic separation was accomplished on a ZORBAX SB-C18 (250 mm×4.6 mm, 5.0 μm) column using gradient elution of methanol and 0.1‰ acetic acid v/v at a flow rate of 1.0 mL/min. The identification and quantification of the analytes were achieved using negative electrospray ionization mass spectrometry in multiple-reaction monitoring mode. The method was fully validated in terms of limits of detection and quantification, linearity, precision and accuracy. The results indicated that the developed method is simple, rapid, specific and reliable. Furthermore, the developed method was successfully applied to quantify the 25 active components in six batches of total flavonoids extract from Herba Desmodii Styracifolii.

  19. Ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry coupled with hierarchical cluster analysis to evaluate Wikstroemia indica (L.) C. A. Mey. from different geographical regions.

    Science.gov (United States)

    Wei, Lan; Wang, Xiaobo; Mu, Shanxue; Sun, Lixin; Yu, Zhiguo

    2015-06-01

    A sensitive, rapid and simple ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry method was developed to determine seven constituents (umbelliferone, apigenin, triumbelletin, daphnoretin, arctigenin, genkwanin and emodin) in Wikstroemia indica (L.) C. A. Mey. The chromatographic analysis was performed on an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 μm) by gradient elution with the mobile phase of 0.05% formic acid aqueous solution (A) and acetonitrile (B). Multiple reaction monitoring mode with positive and negative electrospray ionization interface was carried out to detect the components. This method was validated in terms of specificity, linearity, accuracy, precision and stability. Excellent linear behavior was observed over the certain concentration ranges with the correlation coefficient values higher than 0.999. The intraday and innerday precisions were within 2.0%. The recoveries of seven analytes were 99.4-101.1% with relative standard deviation less than 1.2%. The 18 Wikstroemia indica samples from different origins were classified by hierarchical clustering analysis according to the contents of seven components. The results demonstrated that the developed method could successfully be used to quantify simultaneously of seven components in Wikstroemia indica and could be a helpful tool for the detection and confirmation of the quality of traditional Chinese medicines.

  20. Determination of torasemide in human plasma and its bioequivalence study by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry$

    Institute of Scientific and Technical Information of China (English)

    Lin Zhang; Rulin Wang; Yuan Tian; Zunjian Zhang

    2016-01-01

    A sensitive and selective method using high-performance liquid chromatography coupled with elec-trospray ionization tandem mass spectrometry (HPLC–ESI–MS) to determine the concentration of tor-asemide in human plasma samples was developed and validated. Tolbutamide was chosen as the internal standard (IS). The chromatography was performed on a Gl Sciences Inertsil ODS-3 column (100 mm ? 2.1 mm i.d., 5.0 mm) within 5 min, using methanol with 10 mM ammonium formate (60:40, v/v) as mobile phase at a flow rate of 0.2 mL/min. The targeted compound was detected in negative io-nization at m/z 347.00 for torasemide and 269.00 for IS. The linearity range of this method was found to be within the concentration range of 1–2500 ng/mL (r¼0.9984) for torasemide in human plasma. The accuracy of this measurement was between 94.05%and 103.86%. The extracted recovery efficiency was from 84.20% to 86.47% at three concentration levels. This method was also successfully applied in pharmacokinetics and bioequivalence studies in Chinese volunteers.

  1. Liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry for Simultaneous Determination of Metformin and Glimepiride in Beagle Dog Plasma and Bioequivalence Study

    Institute of Scientific and Technical Information of China (English)

    BAI Jing; SHI Xiao-wei; DU Ying-feng; XIANG Bai; WANG Shuai; CAO De-ying

    2012-01-01

    A sensitive and selective liquid chromatography-electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS) was used for the simultaneous determination of metformin and glimepiride in beagle dog plasma with glipizide as internal standard(IS).After simplified protein precipitation with methanol,both the analytes and IS were chromatographed on a Zorbax CN column via gradient elution with methanol(containing 5 mmol/L ammonium acetate) and 5 mmol/L aqueous ammonium acetate as the mobile phase.Detection was performed by multiple reaction monitoring(MRM) scanning via ESI source operated in positive ionization mode.Specificity,linearity,accuracy,precision,recovery,matrix effect and stability were validated for metformin and glimepiride in beagle dog plasma.The calibration curves were linear in a concentration range of 10--10000 ng/mL for metformin and 4--4000 ng/mL for glimepiride with both correlation coefficients higher than 0.99.The recoveries obtained for the analytes and IS were all between 82.7% and 101.2%.The method exhibited excellent performance in terms of selectivity,robustness,short analytical time and simplicity of sample preparation.Finally,the proposed method was applied to a bioequivalence study of self-made bilayer tablet and commercial formulation containing 500 mg of metformin and 1 mg of glimepiride in beagle dogs.

  2. Identification of heat-induced degradation products from purified betanin, phyllocactin and hylocerenin by high-performance liquid chromatography/electrospray ionization mass spectrometry.

    Science.gov (United States)

    Herbach, Kirsten M; Stintzing, Florian C; Carle, Reinhold

    2005-01-01

    Betanin, phyllocactin (malonylbetanin) and hylocerenin (3-hydroxy-3-methylglutarylbetanin) were isolated from purple pitaya (Hylocereus polyrhizus [Weber] Britton and Rose) juice, and their degradation products generated by heating at 85 degrees C were subsequently monitored by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. Thermal degradation of phyllocactin and hylocerenin in purified solution excluding the alleged protective effects by the juice matrix is reported for the first time. Betanin was predominantly degraded by hydrolytic cleavage, while decarboxylation and dehydrogenation were of minor relevance. In contrast, hylocerenin showed a strong tendency to decarboxylation and dehydrogenation, hydrolytic cleavage of the aldimine bond occurring secondarily. Phyllocactin degradation was most complex because of additional decarboxylation of the malonic acid moiety as well as generation and subsequent degradation of betanin due to phyllocactin demalonylation. Upon prolonged heating, all betacyanins under observation formed degradation products characterized by an additional double bond at C2-C3. Hydrolytic cleavage of the aldimine bond of phyllocactin and hylocerenin yielded previously unknown acylated cyclo-dopa derivatives traceable by positive ionization, while application of ESI(-) facilitated the detection of a glycosylated aminopropanal derivative and dopamine, which have never been described before as betanin degradation products.

  3. Development and validation of an ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method for the simultaneous determination of selected flavonoids in Ginkgo biloba.

    Science.gov (United States)

    Pandey, Renu; Chandra, Preeti; Arya, Kamal Ram; Kumar, Brijesh

    2014-12-01

    A rapid and sensitive ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous determination of 13 flavonoids in leaf, stem, and fruit extracts of male and female trees of Ginkgo biloba to investigate gender- and age-related variations of flavonoids content. Chromatographic separation was accomplished on an Acquity UPLC BEH C18 column (50 mm × 2.1 mm id, 1.7 μm) in 5 min. Quantitation was performed using negative electrospray ionization mass spectrometry in multiple reaction monitoring mode. The calibration curves of all analytes showed a good linear relationship (r(2) ≥ 0.9977) over the concentration range of 1-1000 ng/mL. The precision evaluated by an intra- and interday study showed RSD ≤ 1.98% and good accuracy with overall recovery in the range from 97.90 to 101.09% (RSD ≤ 1.67%) for all analytes. The method sensitivity expressed as the limit of quantitation was typically 0.25-3.57 ng/mL. The results showed that the total content of 13 flavonoids was higher in the leaf extract of an old male Ginkgo tree compared to young female Ginkgo trees.

  4. Simultaneous determination of quetiapine and three metabolites in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Kun-yanLI; Ze-nengCHENG; XinLI; Xue-lianBAI; Bi-kuiZHANG; FengWANG; Huan-deLI

    2004-01-01

    AIM:To develop a high performance liquid chromatography-electrospray mass spectrometry (HPLC-MS/ESI)method for simultaneous determination of quetiapine and its sulfoxide-, 7-hydroxy-, 7-hydroxy-N-dealkyl-metabolites in human plasma. METHODS: The HPLC separation of the compounds was performed on a Kromasil C18, (5μm, 4.6 mm×150 mm) column, using water (formic acid: 1.70 mmol/L, ammonium acetate: 5.8 mmol/L)-acetoni-trile (65:35) as mobile phase, with a flow-rate of 0.95 mL/min. The compounds were ionized in the electrospray ionization (ESI) ion source of the mass spectrometer and detected in the selected ion recording (SIR) mode. The samples were extracted using solid-phase extraction columns. RESULTS: The calibration curves were linear in theranges of 10-2000 μg/L for quetiapine, 1-200 μg/L for its metabolites, respectively. The average extraction recoveries for all the four samples were above 85 %. The methodology recoveries were much higher than 95 %. Theintra-day and inter-day RSD are less than 15 %. CONCLUSION: The method is accurate, sensitive, and simple for study of pharmacokinetics and metabolic mechanism of quetiapine in patients at therapeutic dose.

  5. Determination of polycyclic aromatic hydrocarbons in fractions in asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-07-01

    An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene.

  6. In situ measurements of krypton in xenon gas with a quadrupole mass spectrometer following a cold-trap at a temporarily reduced pumping speed

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Ethan; Rosendahl, Stephan; Huhmann, Christian; Kettling, Hans; Schlak, Martin; Weinheimer, Christian [Muenster Univ. (Germany). Inst. fuer Kernphysik

    2013-07-01

    Liquid xenon detectors have risen to be extremely competitive for dark matter and neutrinoless double-beta decay searches. In order to achieve the required sensitivity, backgrounds must be reduced substantially. One important background is the beta-decay of {sup 85}Kr, which constitutes a uniform internal background in liquid xenon detectors. Cryogenic distillation can be used to reduce the krypton concentration to acceptable levels, but gas diagnostics become incredibly difficult at these ultra-pure levels. A new method for measuring the concentration of krypton in xenon has been developed, expanding on the existing technique of a cold trap and a Residual Gas Analyzer (RGA). By using a liquid nitrogen cold trap, one can take advantage of the difference in vapor pressures of krypton in xenon to freeze most of the xenon gas while allowing the krypton to pass to the measurement chamber. Here, only a few milliliters of xenon is expended in the measurement, while achieving a sensitivity of sub ppb (parts per billion). The key change is the use of a butterfly valve to partially close the opening in front of the turbomolecular pump, thereby reducing the effective pumping speed and enhancing the RGA signal.

  7. Transdermal diffusion of xenon in vitro using diffusion cells

    Science.gov (United States)

    Verkhovsky, A.; Petrov, E.

    2015-11-01

    The aim of this research was to study the diffusion rate of xenon through guinea pig skin and how viscosity of cosmetic component capryl/capric triglyceride (CCT) facilitates to deliver xenon to surface of skin patches. They were placed in Franz cell for 24 hours and diffusion rate and permeability of xenon were calculated. Thus diffusion rate was 0.031 mg/hour*cm2 and permeability was 0.003 cm/hour. Using Brookfield viscometer it was shown that viscosity of CCT decreased upon increasing xenon concentration. Obtained results can be utilized in developing of new xenon containing drugs for topical administration.

  8. Simultaneous flame ionization and absorbance detection of volatile and nonvolatile compounds by reversed-phase liquid chromatography with a water mobile phase.

    Science.gov (United States)

    Bruckner, C A; Ecker, S T; Synovec, R E

    1997-09-01

    A flame ionization detector (FID) is used to detect volatile organic compounds that have been separated by water-only reversed-phase liquid chromatography (WRP-LC). The mobile phase is 100% water at room temperature, without use of organic solvent modifiers. An interface between the LC and detector is presented, whereby a helium stream samples the vapor of volatile components from individual drops of the LC eluent, and the vapor-enriched gas stream is sent to the FID. The design of the drop headspace cell is simple because the water-only nature of the LC separation obviates the need to do any organic solvent removal prior to gas phase detection. Despite the absence of organic modifier, hydrophobic compounds can be separated in a reasonable time due to the low phase volume ratio of the WRP-LC columns. The drop headspace interface easily handles LC flows of 1 mL/min, and, in fact, compound detection limits are improved at faster liquid flow rates. The transfer efficiency of the headspace interface was estimated at 10% for toluene in water at 1 mL/min but varies depending on the volatility of each analyte. The detection system is linear over more than 5 orders of 1-butanol concentration in water and is able to detect sub-ppb amounts of o-xylene and other aromatic compounds in water. In order to analyze volatile and nonvolatile analytes simultaneously, the FID is coupled in series to a WRP-LC system with UV absorbance detection. WRP-LC improves UV absorbance detection limits because the absence of organic modifier allows the detector to be operated in the short-wavelength UV region, where analytes generally have significantly larger molar absorptivities. The selectivity the headspace interface provides for flame ionization detection of volatiles is demonstrated with a separation of 1-butanol, 1,1,2-trichloroethane (TCE), and chlorobenzene in a mixture of benzoic acid in water. Despite coelution of butanol and TCE with the benzoate anion, the nonvolatile benzoate anion

  9. Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source for Elemental Mass Spectrometry: Preliminary Parametric Evaluation and Figures of Merit

    Energy Technology Data Exchange (ETDEWEB)

    Quarles, C. Derrick; Carado, Anthony J.; Barinaga, Charles J.; Koppenaal, David W.; Marcus, R. Kenneth

    2012-01-01

    A new, low power ionization source for the elemental analysis of aqueous solutions has recently been described. The liquid sampling-atmospheric pressure glow discharge (LS-APGD) source operates at relatively low currents (<20 mA) and solution flow rates (<50 μL min-1), yielding a relatively simple alternative for atomic mass spectrometry applications. The LS-APGD has been interfaced to what is otherwise an organic, LC-MS mass analyzer, the Thermo Scientific Exactive Orbitrap without any modifications; other than removing the electrospray ionization (ESI) source supplied with that instrument. A glow discharge is initiated between the surface of the test solution exiting a glass capillary and a metallic counter electrode mounted at a 90° angle and separated by a distance of ~5 mm. As with any plasma-based ionization source, there are key discharge operation and ion sampling parameters that affect the intensity and composition of the derived mass spectra; including signal-to-background ratios. We describe here a preliminary parametric evaluation of the roles of discharge current, solution flow rate, argon sheath gas flow rate, and ion sampling distance as they apply on this mass analyzer system. A cursive evaluation of potential matrix effects due to the presence of easily ionized elements (EIEs) indicate that sodium concentrations of up to 500 μg mL-1 generally cause suppressions of less than 50%, dependant upon the analyte species. Based on the results of this series of studies, preliminary limits of detection (LOD) have been established through the generation of calibration functions. Whilst solution-based concentrations LOD levels of 0.02 – 2 μg mL-1 3 are not impressive on the surface, the fact that they are determined via discrete 5 μL injections leads to mass-based detection limits at picogram to singlenanogram levels. The overhead costs associated with source operation (10 W d.c. power, solution flow rates of <50 μL min-1, and gas flow rates <10 mL min

  10. A hybrid fluorous monolithic capillary column with integrated nanoelectrospray ionization emitter for determination of perfluoroalkyl acids by nano-liquid chromatography-nanoelectrospray ionization-mass spectrometry/mass spectrometry.

    Science.gov (United States)

    Zhang, Haiyang; Ou, Junjie; Wei, Yinmao; Wang, Hongwei; Liu, Zhongshan; Zou, Hanfa

    2016-04-01

    A hybrid fluorous monolithic column was simply prepared via photo-initiated free radical polymerization of an acrylopropyl polyhedral oligomeric silsesquioxane (acryl-POSS) and a perfluorous monomer (2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate) in UV-transparent fused-silica capillaries within 5min. The physical characterization of hybrid fluorous monolith, including scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, mercury intrusion porosimetry (MIP) and nitrogen adsorption/desorption measurement was performed. Chromatographic performance was also evaluated by capillary liquid chromatography (cLC). Due to the fluorous-fluorous interaction between fluorous monolith and analytes, fluorobenzenes could well be separated, and the column efficiencies reached 86,600-92,500plates/m at the velocity of 0.87mm/s for alkylbenzenes and 51,900-76,000plates/m at the velocity of 1.10mm/s for fluorobenzenes. Meanwhile, an approach to integrate nanoelectrospray ionization (ESI) emitter with hybrid fluorous monolithic column was developed for quantitative determination of perfluoroalkyl acids by nanoHPLC-ESI-MS/MS. The integration design could minimize extracolumn volume, thus excluding undesirable peak broadening and improving separation performance.

  11. Position Reconstruction in a Dual Phase Xenon Scintillation Detector

    CERN Document Server

    Solovov, V N; Akimov, D Yu; Araújo, H M; Barnes, E J; Burenkov, A A; Chepel, V; Currie, A; DeViveiros, L; Edwards, B; Ghag, C; Hollingsworth, A; Horn, M; Kalmus, G E; Kobyakin, A S; Kovalenko, A G; Lebedenko, V N; Lindote, A; Lopes, M I; Lüscher, R; Majewski, P; Murphy, A St J; Neves, F; Paling, S M; da Cunha, J Pinto; Preece, R; Quenby, J J; Reichhart, L; Scovell, P R; Silva, C; Smith, N J T; Smith, P F; Stekhanov, V N; Sumner, T J; Thorne, C; Walker, R J

    2011-01-01

    We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated gamma-ray source. Using the techniques described, the performance of the ZEPLIN-III dark matter detector was studied for 122 keV gamma-rays. For the inner part of the detector (R<100 mm), spatial resolutions of 13 mm and 1.6 mm FWHM were measured in the horizontal plane for primary and secondary scintillation, respectively. An energy resolution of 8.1% FWHM was achieved at that energy. The possibility of using this technique for improving performance and reducing cost of scintillation cameras for medical applications is currently under study.

  12. High-power atomic xenon laser

    NARCIS (Netherlands)

    Witteman, W.J.; Peters, P.J.M.; Botma, H.; Botma, H.; Tskhai, S.N.; Udalov, Yu.B.; Mei, Q.C.; Mei, Qi-Chu; Ochkin, V.N.

    1995-01-01

    The high pressure atomic xenon laser is becoming the most promising light source in the wavelength region of a few microns. The merits are high efficiency (so far up to 8 percent), high output energies (15 J/liter at 9 bar), high continuous output power (more than 200 W/liter), no gas dissociation a

  13. Pattern recognition of $^{136}$Xe double beta decay events and background discrimination in a high pressure Xenon TPC

    CERN Document Server

    Cebrian, S; Gomez, H; Herrera, D C; Iguaz, F J; Irastorza, I G; Luzon, G; Segui, L; Tomas, A

    2013-01-01

    High pressure gas detectors offer advantages for the detection of rare events, where background reduction is crucial. For the neutrinoless double beta decay of 136Xe a high pressure xenon gas Time Projection Chamber (TPC) combines a good energy resolution and a detailed topological information of each event. The ionization topology of the double beta decay event of 136Xe in gaseous xenon has a characteristic shape defined by the two straggling electron tracks ending up in two higher ionization charge density blobs. With a properly pixelized readout, this topological information is invaluable to perform powerful background discrimination. In this study we carry out detailed simulations of the signal topology, as well as the competing topologies from gamma events that typically compose the background at these energies. We define observables based on graph theory concepts and develop automated discrimination algorithms which reduce the background level in around three orders of magnitude while keeping signal eff...

  14. Determination of the separation efficiencies of a single-stage cryogenic distillation setup to remove krypton out of xenon by using a (83m)Kr tracer method.

    Science.gov (United States)

    Rosendahl, S; Brown, E; Cristescu, I; Fieguth, A; Huhmann, C; Lebeda, O; Murra, M; Weinheimer, C

    2015-11-01

    The separation of krypton and xenon is of particular importance for the field of direct dark matter search with liquid xenon detectors. The intrinsic contamination of the xenon with radioactive (85)Kr makes a significant background for these kinds of low count-rate experiments and has to be removed beforehand. This can be achieved by cryogenic distillation, a technique widely used in industry, using the different vapor pressures of krypton and xenon. In this paper, we present an investigation on the separation performance of a single stage distillation system using a radioactive (83m)Kr-tracer method. The separation characteristics under different operation conditions are determined for very low concentrations of krypton in xenon at the level of (83m)Kr/Xe = 1.9 ⋅ 10(-15), demonstrating, that cryogenic distillation in this regime is working. The observed separation is in agreement with the expectation from the different volatilities of krypton and xenon. This cryogenic distillation station is the first step on the way to a multi-stage cryogenic distillation column for the next generation of direct dark matter experiment XENON1T.

  15. Boosting the Detection Potential of Liquid Chromatography-Electron Ionization Mass Spectrometry Using a Ceramic Coated Ion Source

    Science.gov (United States)

    Magrini, Laura; Famiglini, Giorgio; Palma, Pierangela; Termopoli, Veronica; Cappiello, Achille

    2016-01-01

    Detection of target and non-target substances and their characterization in complex samples is a challenging task. Here we demonstrate that coating the electron ionization (EI) ion source of an LC-MS system with a sol-gel ceramic film can drastically improve the detection of high-molecular weight and high-boiling analytes. A new ion source coated with a ceramic material was developed and tested with a mixture of polycyclic aromatic hydrocarbons (PAH) with an increasing number of rings. Comparison of the results obtained with those for an uncoated stainless steel (SS) ion source shows a dramatic improvement in the MS signals, with a nearly 40-fold increase of the signal-to-noise ratio. We also demonstrate the ability of the new system to produce excellent chromatographic profiles for hard-to-detect hormones.

  16. Quantification of intracellular phosphorylated carbohydrates in HT29 human colon adenocarcinoma cell line using liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Vizán, Pedro; Alcarraz-Vizán, Gema; Díaz-Moralli, Santiago; Rodríguez-Prados, Juan Carlos; Zanuy, Míriam; Centelles, Josep J; Jáuregui, Olga; Cascante, Marta

    2007-07-01

    The quantitative understanding of the role of sugar phosphates in regulating tumor energetic metabolism at the proteomic and genomic level is a prerequisite for an efficient rational design in combined drug chemotherapy. Therefore, it is necessary to determine accurately the concentration of the main sugar phosphate pools at the lower concentrations present in the often-limited volume of tumor cell samples. Taking as an example the human adenocarcinoma cell line HT29, we here report a fast and reliable quantitative method based on the use of liquid nitrogen, a weak acid extraction, and liquid chromatography-electrospray ionization tandem mass spectrometry to quantify simultaneously the intracellular concentration of sugar phosphate pools. The method was set up using standard addition curves. Thus, it is possible to identify and quantify hexose phosphate, pentose phosphate, and triose phosphate pools up to 0.02-0.10 ng x microL(-1), depending on the analyte. The method developed was here used for the quantitative study of changes in phosphorylated carbohydrates of central carbon metabolism when high or low glucose concentration conditions are induced in vitro in the HT29 human colon adenocarcinoma cell line.

  17. Liquid Microjunction Surface Sampling Coupled with High-Pressure Liquid Chromatography-Electrospray Ionization-Mass Spectrometry for Analysis of Drugs and Metabolites in Whole-Body Thin Tissue Sections

    Energy Technology Data Exchange (ETDEWEB)

    Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2010-01-01

    In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, two isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent.

  18. Identification and Quantification of the Major Constituents in Egyptian Carob Extract by Liquid Chromatography–Electrospray Ionization-Tandem Mass Spectrometry

    Science.gov (United States)

    Owis, Asmaa Ibrahim; El-Naggar, El-Motaz Bellah

    2016-01-01

    Background: Carob - Ceratonia siliqua L., commonly known as St John's-bread or locust bean, family Fabaceae - is one of the most useful native Mediterranean trees. There is no data about the chromatography methods performed by high performance liquid chromatography (HPLC) for determining polyphenols in Egyptian carob pods. Objective: To establish a sensitive and specific liquid chromatography–electrospray ionization (ESI)-tandem mass spectrometry (MSn) methodology for the identification of the major constituents in Egyptian carob extract. Materials and Methods: HPLC with diode array detector and ESI-mass spectrometry (MS) was developed for the identification and quantification of phenolic acids, flavonoid glycosides, and aglycones in the methanolic extract of Egyptian C. siliqua. The MS and MSn data together with HPLC retention time of phenolic components allowed structural characterization of these compounds. Peak integration of ions in the MS scans had been used in the quantification technique. Results: A total of 36 compounds were tentatively identified. Twenty-six compounds were identified in the negative mode corresponding to 85.4% of plant dry weight, while ten compounds were identified in the positive mode representing 16.1% of plant dry weight, with the prevalence of flavonoids (75.4% of plant dry weight) predominantly represented by two methylapigenin-O-pentoside isomers (20.9 and 13.7% of plant dry weight). Conclusion: The identification of various compounds present in carob pods opens a new door to an increased understanding of the different health benefits brought about by the consumption of carob and its products. SUMMARY This research proposed a good example for the rapid identification of major constituents in complex systems such as herbs using sensitive, accurate and specific method coupling HPLC with DAD and MS, which facilitate the clarification of phytochemical composition of herbal medicine for better understanding of their nature and

  19. Evaluation of the operating parameters of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source for elemental mass spectrometry.

    Science.gov (United States)

    Zhang, Lynn X; Manard, Benjamin T; Konegger-Kappel, Stefanie; Kappel, Stefanie Konegger; Marcus, R Kenneth

    2014-11-01

    The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as an ionization source for elemental analysis with an interdependent, parametric evaluation regarding sheath/cooling gas flow rate, discharge current, liquid flow rate, and the distance between the plasma and the sampling cone of the mass spectrometer. In order to better understand plasma processes (and different from previous reports), no form of collision/reaction processing was performed to remove molecular interferents. The evaluation was performed employing five test elements: cesium, silver, lead, lanthanum and nickel (10(-4) mol L(-1) in 1 mol L(-1) HNO3). The intensity of the atomic ions, levels of spectral background, the signal-to-background ratios, and the atomic-to-oxide/hydroxide adduct ratios were monitored in order to obtain fundamental understanding with regards to not only how each parameter effects the performance of this LS-APGD source, but also the inter-parametric effects. The results indicate that the discharge current and the liquid sampling flow rates are the key aspects that control the spectral composition. A compromise set of operating conditions was determined: sheath gas flow rate = 0.9 L min(-1), discharge current = 10 mA, solution flow rate = 10 μL min(-1), and sampling distance = 1 cm. Limits of detection (LODs) were calculated using the SBR-RSDB (signal-to-background ratio/relative standard deviation of the background) approach under the optimized condition. The LODs for the test elementals ranged from 15 to 400 ng mL(-1) for 10 μL injections, with absolute mass values from 0.2 to 4 ng.

  20. Interactions between xenon and phospholipid bicelles studied by 2H/ 129Xe/ 131Xe NMR and optical pumping of nuclear spins

    Science.gov (United States)

    Li, Xiaoxia; Newberry, Caitlin; Saha, Indrajit; Nikolaou, Panayiotis; Whiting, Nicholas; Goodson, Boyd M.

    2006-02-01

    The interactions between xenon and DMPC/DHPC bicelles ( q = 3.5%, 7.5% w/v) were studied via 2H, 129Xe, 131Xe, and optically enhanced 129Xe NMR. The chemical shifts, linewidths, and quadrupolar couplings of the xenon/bicelle NMR signals were correlated with different regions of the bicellar phase diagram. The addition of xenon (<70 mM) was observed to reduce the temperature-onset of bicelle alignment by several degrees, in quantitative agreement with effects previously observed with chloroform; however, the stable liquid-crystalline range was not significantly reduced. Preliminary laser-polarized xenon/bicelle studies yielded 129Xe T1 values of ˜120 s, long enough to permit a variety of planned experiments.

  1. Quantitative analysis of paraquat in vegetation by stable isotope dilution and liquid chromatography/electrospray ionization-mass spectrometry.

    Science.gov (United States)

    Schaner, Angela; Hickes, Heidi

    2015-01-01

    The method presented is a suitable approach for routine testing of paraquat in difficult sample types, such as winter wheat and alfalfa plant tissue, typically found with accidental spray drift. Hydrophilic interaction chromatography and ultra-performance LC is utilized with tandem quadrupole MS in the positive electrospray ionization mode. Three precursor-product ion transitions are measured in the multiple reaction monitoring mode, and paraquat d8 is added as an internal standard at the beginning of the extraction procedure to correct for losses in recovery and/or matrix effects in instrument response. A 5 g portion is digested with 6 M HCl in a 100°C water bath for 1 h. An aliquot is removed and adjusted to pH 7-8 prior to loading on a mixed mode weak cation-exchange SPE cartridge, and paraquat is eluted with formic acid-acetonitrile (10 + 90, v/v). Average recoveries of paraquat fortified at 0.020-0.080 ppm in winter wheat and alfalfa ranged from 80 to 114% (RSD 12-30%). Result data from naturally incurred paraquat (0.027-0.51 ppm) in composite garden plants, potato leaves, tree leaves, and alfalfa are presented. The LOQ is 0.020 ppm.

  2. Preliminary Assessment of Potential for Metal-Ligand Speciation in Aqueous Solution via the Liquid Sampling-Atmospheric Pressure Glow Discharge (LS-APGD) Ionization Source: Uranyl Acetate.

    Science.gov (United States)

    Zhang, Lynn X; Manard, Benjamin T; Powell, Brian A; Marcus, R Kenneth

    2015-07-21

    The determination of metals, including the generation of metal-ligand speciation information, is essential across a myriad of biochemical, environmental, and industrial systems. Metal speciation is generally affected by the combination of some form of chromatographic separation (reflective of the metal-ligand chemistry) with element-specific detection for the quantification of the metal composing the chromatographic eluent. Thus, the identity of the metal-ligand is assigned by inference. Presented here, the liquid sampling-atmospheric pressure glow discharge (LS-APGD) is assessed as an ionization source for metal speciation, with the uranyl ion-acetate system used as a test system. Molecular mass spectra can be obtained from the same source by simple modification of the sustaining electrolyte solution. Specifically, chemical information pertaining to the degree of acetate complexation of uranyl ion (UO2(2+)) is assessed as a function of pH in the spectral abundance of three metallic species: inorganic (nonligated) uranyl, UO2Ac(H2O)n(MeOH)m(+), and UO2Ac2(H2O)n(MeOH)(m)H(+) (n = 1, 2, 3, ...; m = 1, 2, 3, ...). The product mass spectra are different from what are obtained from electrospray ionization sources that have been applied to this system. The resulting relationships between the speciation and pH values have been compared to calculated concentrations of the corresponding uranyl species: UO2(2+), UO2Ac(+), UO2Ac2. The capacity for the LS-APGD to affect both atomic mass spectra and structurally significant spectra for organometallic complexes is a unique and potentially powerful combination.

  3. Determination of pharmaceutical compounds in surface- and ground-water samples by solid-phase extraction and high-performance liquid chromatography-electrospray ionization mass spectrometry

    Science.gov (United States)

    Cahill, J.D.; Furlong, E.T.; Burkhardt, M.R.; Kolpin, D.; Anderson, L.G.

    2004-01-01

    Commonly used prescription and over-the-counter pharmaceuticals are possibly present in surface- and ground-water samples at ambient concentrations less than 1 μg/L. In this report, the performance characteristics of a combined solid-phase extraction isolation and high-performance liquid chromatography–electrospray ionization mass spectrometry (HPLC–ESI-MS) analytical procedure for routine determination of the presence and concentration of human-health pharmaceuticals are described. This method was developed and used in a recent national reconnaissance of pharmaceuticals in USA surface waters. The selection of pharmaceuticals evaluated for this method was based on usage estimates, resulting in a method that contains compounds from diverse chemical classes, which presents challenges and compromises when applied as a single routine analysis. The method performed well for the majority of the 22 pharmaceuticals evaluated, with recoveries greater than 60% for 12 pharmaceuticals. The recoveries of angiotensin-converting enzyme inhibitors, a histamine (H2) receptor antagonist, and antihypoglycemic compound classes were less than 50%, but were retained in the method to provide information describing the potential presence of these compounds in environmental samples and to indicate evidence of possible matrix enhancing effects. Long-term recoveries, evaluated from reagent-water fortifications processed over 2 years, were similar to initial method performance. Method detection limits averaged 0.022 μg/L, sufficient for expected ambient concentrations. Compound-dependent matrix effects on HPLC/ESI-MS analysis, including enhancement and suppression of ionization, were observed as a 20–30% increase in measured concentrations for three compounds and greater than 50% increase for two compounds. Changing internal standard and more frequent ESI source maintenance minimized matrix effects. Application of the method in the national survey demonstrates that several

  4. Normal phase liquid chromatography coupled to quadrupole time of flight atmospheric pressure chemical ionization mass spectrometry for separation, detection and mass spectrometric profiling of neutral sphingolipids and cholesterol.

    Science.gov (United States)

    Farwanah, Hany; Wirtz, Jennifer; Kolter, Thomas; Raith, Klaus; Neubert, Reinhard H H; Sandhoff, Konrad

    2009-10-01

    Many lipidomic approaches focus on investigating aspects of sphingolipid metabolism. Special emphasis is put on neutral sphingolipids and cholesterol and their interaction. Such an interest is attributed to the fact that those lipids are altered in a series of serious disorders including various sphingolipidoses. High performance thin-layer chromatography (HPTLC) has become a widely used technique for lipid analysis. However, mass spectrometric profiling is irreplaceable for gaining an overview about the various molecular species within a lipid class. In this work we have developed a sensitive method based on a gradient normal phase high performance liquid chromatography (HPLC) coupled to quadrupole time of flight (QTOF) atmospheric pressure chemical ionization mass spectrometry (APCI-MS) in positive mode, which for the first time enables separation, on-line detection, and mass spectrometric profiling of multiple neutral sphingolipids including ceramide, glucosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, sphingomyelin as well as cholesterol within less than 15min. An important advantage of the presented HPLC/APCI-MS approach is that the separation pattern emulates the one obtained by an optimized HPTLC method with a multiple stage development. Thus, the lipid classes previously separated and quantified by HPTLC can be easily screened regarding their mass spectrometric profiles by HPLC/APCI-MS. In addition, the selected ionization conditions enable in-source fragmentation providing useful structural information. The methods (HPLC/APCI-MS and the optimized HPTLC) were applied for the analysis of the mentioned lipids in human fibroblasts. This approach is aimed basically at investigators who perform studies based on genetic modifications or treatment with pharmacological agents leading to changes in the biochemical pathways of neutral sphingolipids and cholesterol. In addition, it can be of interest for research on disorders related to

  5. Determination of oxygen and nitrogen derivatives of polycyclic aromatic hydrocarbons in fractions of asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-12-01

    Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 μg/L for nitrated and from 0.1 to 6.6 μg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 μg/L for nitrated and 0.3-8.9 μg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected.

  6. Characterisation of NEXT-DEMO using xenon K$_{\\alpha}$ X-rays

    CERN Document Server

    Lorca, D; Laing, A; Ferrario, P; Gómez-Cadenas, J J; Álvarez, V; Borges, F I G; Camargo, M; Cárcel, S; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Díaz, J; Esteve, R; Fernandes, L M P; Ferreira, A L; Freitas, E D C; Gehman, V M; Goldschmidt, A; Gómez, H; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Irastorza, I G; Labarga, L; Liubarsky, I; Losada, M; Luzón, G; Marí, A; Martínez-Lema, G; Martínez, A; Miller, T; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; Nebot-Guinot, M; Nygren, D; Oliveira, C A B; Pérez, J; Aparicio, J L Pérez; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Seguí, L; Serra, L; Shuman, D; Simón, A; Sofka, C; Sorel, M; Toledo, J F; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Webb, R; White, J T; Yahlali, N

    2014-01-01

    The NEXT experiment aims to observe the neutrinoless double beta decay of $^{136}$Xe in a high pressure gas TPC using electroluminescence (EL) to amplify the signal from ionization. Understanding the response of the detector is imperative in achieving a consistent and well understood energy measurement. The abundance of xenon k-shell x-ray emission during data taking has been identified as a multitool for the characterisation of the fundamental parameters of the gas as well as the equalisation of the response of the detector. The NEXT-DEMO prototype is a ~1.5 kg volume TPC filled with natural xenon. It employs an array of 19 PMTs as an energy plane and of 256 SiPMs as a tracking plane with the TPC light tube and SiPM surfaces being coated with tetraphenyl butadiene (TPB) which acts as a wavelength shifter for the VUV scintillation light produced by xenon. This paper presents the measurement of the properties of the drift of electrons in the TPC, the effects of the EL production region, and the extraction of p...

  7. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression.

    Science.gov (United States)

    Zheng, J; Gu, Y J; Chen, Z Y; Chen, Q F

    2010-08-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ∼6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  8. Highly sensitive derivatization reagents possessing positively charged structures for the determination of oligosaccharides in glycoproteins by high-performance liquid chromatography electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Min, Jun Zhe; Nagai, Keisuke; Shi, Qing; Zhou, Wenjun; Todoroki, Kenichiro; Inoue, Koichi; Lee, Yong-Ill; Toyo'oka, Toshimasa

    2016-09-23

    We have developed three kinds of novel derivatization reagents (4-CEBTPP, 4-CBBTPP, 5-COTPP) with triphenylphosphine (TPP) as a basic structure carrying a permanent positive charge for resolution of the oligosaccharides in glycoprotein using high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The synthesized reagents reacted with the sialylglycosylamine of the sialylglycopeptide after treatment by PNGase F. The final derivatives were analyzed by ESI-MS and sensitively detected in the selected reaction monitoring (SRM) mode. Furthermore, the limits of detection (S/N=3) on the SRM chromatograms were at the fmol level (30fmol). Therefore, we used the limit of detection of the reagent products detected by the SRM and evaluated the utility of each reagent. Among the reagents, the positively charged 4-CEBTPP derivative's peak area was the highest; 4-CEBTPP with a positively charged structure showed about a 20 times greater sensitivity for the glycosylamine of the SGP product compared to the conventional fluorescence reagent, Fmoc-Cl. In addition, various fragment ions based on the carbohydrate units also appeared in the MS/MS spectra. Among the fragment ions, m/z 627.37 (CE=40eV) corresponding to 4-CEBTPP-GlcNAc and m/z 120.09 (CE=100eV) corresponding to 4-CEBTPP are the most important ones for identifying the oligosaccharide. 4-CEBTPP-SGA was easily identified by the selected-ion chromatogram in the product ion scan (m/z 120.09) and in the precursor ion scan (m/z 627.37) by MS/MS detection. The derivatized analytes have a high ionization efficiency and they are detected with a high sensitivity in the electrospray ionization. The novel derivatization reagent with a multi-function provided a higher sensitivity for the oligosaccharide analysis, as well as a better specificity and feasibility. Furthermore, several oligosaccharides in fetuin and ribonuclease B were successfully identified by the proposed procedure.

  9. Coupling of homogeneous liquid-liquid extraction and dispersive liquid-liquid microextraction for the extraction and preconcentration of polycyclic aromatic hydrocarbons from aqueous samples followed by GC with flame ionization detection.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Khiavi, Elahe Behboudi; Khorram, Parisa; Mogaddam, Mohammad Reza Afshar

    2017-01-01

    In the present study, a simple and rapid method for the extraction and preconcentration of some polycyclic aromatic hydrocarbons in water samples has been developed. In this method, two sample preparation methods were combined to obtain high extraction recoveries and enrichment factors for sensitive analysis of the selected analytes. In the first stage of the method, a homogeneous solution containing an aqueous solution and cyclohexyl amine is broken by the addition of a salt. After centrifugation, the upper collected phase containing the extracted analytes is subjected to the following dispersive liquid-liquid microextraction method. Rapid injection of the mixture of cyclohexyl amine resulted from the first stage and 1,1,2-trichloroethane (as an extraction solvent) into an acetic acid solution is led to form a cloudy solution. After centrifuging, the fine droplets of the extraction solvent are settled down in the bottom of the test tube, and an aliquot of it is analyzed by gas chromatography. Under the optimum extraction conditions, enrichment factors and limits of detection for the studied analytes were obtained in the ranges of 616-752 and 0.08-0.20 μg/L, respectively. The simplicity, high extraction efficiency, short sample preparation time, low cost, and safety demonstrated the efficiency of this method relative to other approaches.

  10. Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz; Peña-Garay, C., E-mail: gomez@mail.cern.ch, E-mail: jmalbos@ific.uv.es, E-mail: jmunoz@ific.uv.es, E-mail: penya@ific.uv.es [Instituto de Física Corpuscular (IFIC), CSIC and Universitat de Valencia Calle Catedrático José Beltrán, 2, 46090 Paterna, Valencia (Spain)

    2013-03-01

    The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm{sub ν} = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m{sub ββ} involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely.

  11. Xenon and iodine reveal multiple distinct exotic xenon components in Efremovka "nanodiamonds"

    Science.gov (United States)

    Gilmour, J. D.; Holland, G.; Verchovsky, A. B.; Fisenko, A. V.; Crowther, S. A.; Turner, G.

    2016-03-01

    We identify new xenon components in a nanodiamond-rich residue from the reduced CV3 chondrite Efremovka. We demonstrate for the first time that these, and the previously identified xenon components Xe-P3 and Xe-P6, are associated with elevated I/Xe ratios. The 129I/127I ratio associated with xenon loss from these presolar compositions during processing on planetesimals in the early solar system was (0.369 ± 0.019) × 10-4, a factor of 3-4 lower than the canonical value. This suggests either incorporation of iodine into carbonaceous grains before the last input of freshly synthesized 129I to the solar system's precursor material, or loss of noble gases during processing of planetesimals around 30 Myr after solar system formation. The xenon/iodine ratios and model closure ages were revealed by laser step pyrolysis analysis of a neutron-irradiated, coarse-grained nanodiamond separate. Three distinct low temperature compositions are identified by characteristic I/Xe ratios and 136Xe/132Xe ratios. There is some evidence of multiple compositions with distinct I/Xe ratios in the higher temperature releases associated with Xe-P6. The presence of iodine alongside Q-Xe and these components in nanodiamonds constrains the pathway by which extreme volatiles entered the solid phase and may facilitate the identification of their carriers. There is no detectable iodine contribution to the presolar Xe-HL component, which is released at intermediate temperatures; this suggests a distinct trapping process. Releases associated with the other components all include significant contributions of 128Xe produced from iodine by neutron capture during reactor irradiation. We propose a revised model relating the origin of Xe-P3 (which exhibits an s-process deficit) through a ;Q-process; to the Q component (which makes the dominant contribution to the heavy noble gas budget of primitive material). The Q-process incorporates noble gases and iodine into specific carbonaceous phases with mass

  12. Transmission Electron Diffraction Studies of Xenon Adsorbed on Graphite.

    Science.gov (United States)

    Faisal, A. Q. D.

    1987-09-01

    Available from UMI in association with The British Library. Adsorption studies of xenon on graphite were performed using the Hitachi HU-11B Transmission Electron Microscope (TEM). It has been used as a Transmission High Energy Electron Diffraction (THEED) camera. This has been modified to include an Ultra High Vacuum (UHV) environmental chamber. This chamber was isolated from the microscope vacuum by two 400 μm diameter differentially pumped apertures. Pressures of {~}10 ^{-6} torr and {~ }10^{-9} torr were achieved inside the microscope column and the environmental chamber respectively. The chamber was fitted with a new sample holder designed with double "O" rings. The sample was cooled with liquid helium. Previous THEED experiments by Venables et al and Schabes-Retchkiman and Venables revealed the presence of a 2D-solid incommensurate (I)-commensurate (C) phase transition as the temperature is lowered. These results were confirmed and extended in the present work. Hong et al have recently interpreted their X-ray diffraction experiments as showing an incommensurate-striped domain phase transition at {~}65rm K. No evidence was found for the existence of a striped domain structure on any part of the xenon phase diagram studied. Experiments of xenon adsorbed on the basal plane (0001) of graphite were carried out at pressures from {~}1.5 times 10^{-5} torr to {~}1.8 times 10^{-8} torr over a temperature range from 55K^.90K. A set of lattice parameter (misfit) measurements were made as a function of temperature at constant pressure with an accuracy of +/-0.1% rather than +/-0.3% previously obtained. The misfit data was fitted to a power law formula, i.e. misfit m = B_{rm o} (rm T - rm T_{rm o})^{rm A} , where A is a constant and equal to 0.8. It was found that B_{rm o} and T_{rm o} are functions of log(P). The data fell into two groups corresponding to two phase transitions. The same power law was used for both sets of data. Two transitions were found, one is I-C and

  13. The Large Underground Xenon (LUX) Experiment

    CERN Document Server

    Akerib, D S; Bedikian, S; Bernard, E; Bernstein, A; Bolozdynya, A; Bradley, A; Byram, D; Cahn, S B; Camp, C; Carmona-Benitez, M C; Carr, D; Chapman, J J; Chiller, A; Chiller, C; Clark, K; Classen, T; Coffey, T; Curioni, A; Dahl, E; Dazeley, S; de Viveiros, L; Dobi, A; Dragowsky, E; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Gaitskell, R J; Gibson, K R; Gilchriese, M; Hall, C; Hanhardt, M; Holbrook, B; Ihm, M; Jacobsen, R G; Kastens, L; Kazkaz, K; Knoche, R; Kyre, S; Kwong, J; Lander, R; Larsen, N A; Lee, C; Leonard, D S; Lesko, K T; Lindote, A; Lopes, M I; Lyashenko, A; Malling, D C; Mannino, R; Marquez, Z; McKinsey, D N; Mei, D -M; Mock, J; Moongweluwan, M; Morii, M; Nelson, H; Neves, F; Nikkel, J A; Pangilinan, M; Parker, P D; Pease, E K; Pech, K; Phelps, P; Rodionov, A; Roberts, P; Shei, A; Shutt, T; Silva, C; Skulski, W; Solovov, V N; Sofka, C J; Sorensen, P; Spaans, J; Stiegler, T; Stolp, D; Svoboda, R; Sweany, M; Szydagis, M; Taylor, D; Thomson, J; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, D; White, J T; Whitis, T J; Wlasenko, M; Wolfs, F L H; Woods, M; Zhang, C

    2012-01-01

    The Large Underground Xenon (LUX) collaboration has designed and constructed a dual-phase xenon detector, in order to conduct a search for Weakly Interacting Massive Particles(WIMPs), a leading dark matter candidate. The goal of the LUX detector is to clearly detect (or exclude) WIMPS with a spin independent cross section per nucleon of $2\\times 10^{-46}$ cm$^{2}$, equivalent to $\\sim$1 event/100 kg/month in the inner 100-kg fiducial volume (FV) of the 370-kg detector. The overall background goals are set to have $<$1 background events characterized as possible WIMPs in the FV in 300 days of running. This paper describes the design and construction of the LUX detector.

  14. Determination of cocaine and benzoylecgonine in nails by liquid chromatography-electrospray ionization-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Marzena Sykutera

    2015-02-01

    Full Text Available Nails and hair are a biological matrix which can be analyzed to confirm the use of a xenobiotic even several months after intake. Results of nail analysis can be used, for example, as evidence in civil and criminal law cases in which a history of drug use can influence the court’s decision. The paper presents results of analysis of a nail sample taken from a man who was suspected of trafficking cocaine. The suspect pleaded guilty to the possession of the drug for his own use because, as he claimed, he was addicted to cocaine. A nail sample was taken. Detection and quantification were carried out using liquid chromatography-mass spectrometry (LC-ESI-MS. The concentration of cocaine in nails was found to be 47 ng/mg, and benzoylecgonine – 14 ng/mg.

  15. Profiling of lipid species by normal-phase liquid chromatography, nanoelectrospray ionization, and ion trap-orbitrap mass spectrometry

    DEFF Research Database (Denmark)

    Sokol, Elena; Almeida, Reinaldo; Hannibal-Bach, Hans Kristian

    2013-01-01

    chromatography-Fourier transform mass spectrometry (LC-FTMS) and LC-ITMS(2) (ion trap tandem mass spectrometry) for profiling and structural analysis of lipid species. The workflow uses a normal-phase LC system for efficient separation of apolar and polar lipid species combined with sensitive and specific...... analysis powered by a chip-based nanoelectrospray ion source and a hybrid ion trap-orbitrap mass spectrometer. The workflow was executed using a primary LC-FTMS survey routine for identification and profiling of lipid species based on high-mass accuracy and retention time followed by a targeted LC-ITMS(2......Detailed analysis of lipid species can be challenging due to their structural diversity and wide concentration range in cells, tissues, and biofluids. To address these analytical challenges, we devised a reproducible, sensitive, and integrated lipidomics workflow based on normal-phase liquid...

  16. First Demonstration of a Scintillating Xenon Bubble Chamber for Dark Matter and CE$\

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, D. [Fermilab; Chen, C. J. [Northwestern U.; Crisler, M. [PNL, Richland; Cwiok, T. [Northwestern U.; Dahl, C. E. [Fermilab; Grimsted, A. [Evanston Township High School; Gupta, J. [Northwestern U.; Jin, M. [Northwestern U.; Puig, R. [Northwestern U.; Temples, D. [Northwestern U; Zhang, J. [Northwestern U.

    2017-02-28

    A 30-gram xenon bubble chamber, operated at Northwestern University in June and November 2016, has for the first time observed simultaneous bubble nucleation and scintillation by nuclear recoils in liquid xenon. This chamber is instrumented with a CCD camera for near-IR bubble imaging, a solar-blind PMT to detect 175-nm xenon scintillation light, and a piezoelectric acoustic transducer to detect the ultrasonic emission from a growing bubble. The time-of-nucleation determined from the acoustic signal is used to correlate specific scintillation pulses with bubble-nucleating events. The observed single- and multiple-bubble rates when exposed to a $^{252}$Cf neutron source indicate that, for a thermodynamic "Seitz" threshold of 8.3 keV, the minimum nuclear recoil energy required to nucleate a bubble is between 11 and 25 keV. This is consistent with the observed scintillation spectrum for bubble-nucleating events. We see no evidence for bubble nucleation by gamma rays at the thresholds studied, setting a 90% CL upper limit of $6.3\\times10^{-7}$ bubbles per gamma interaction at a 4.2-keV thermodynamic threshold. This indicates stronger gamma discrimination than in CF$_3$I bubble chambers, supporting the hypothesis that scintillation production suppresses bubble nucleation by electron recoils, while nuclear recoils nucleate bubbles as usual. These measurements establish the noble-liquid bubble chamber as a promising new technology for WIMP and CE$\

  17. Crossover Equation of State Models Applied to the Critical Behavior of Xenon

    Science.gov (United States)

    Garrabos, Y.; Lecoutre, C.; Marre, S.; Guillaument, R.; Beysens, D.; Hahn, I.

    2015-03-01

    The turbidity () measurements of Güttinger and Cannell (Phys Rev A 24:3188-3201, 1981) in the temperature range along the critical isochore of homogeneous xenon are reanalyzed. The singular behaviors of the isothermal compressibility () and the correlation length () predicted from the master crossover functions are introduced in the turbidity functional form derived by Puglielli and Ford (Phys Rev Lett 25:143-146, 1970). We show that the turbidity data are thus well represented by the Ornstein-Zernike approximant, within 1 % precision. We also introduce a new crossover master model (CMM) of the parametric equation of state for a simple fluid system with no adjustable parameter. The CMM model and the phenomenological crossover parametric model are compared with the turbidity data and the coexisting liquid-gas density difference (). The excellent agreement observed for , , , and in a finite temperature range well beyond the Ising-like preasymptotic domain confirms that the Ising-like critical crossover behavior of xenon can be described in conformity with the universal features estimated by the renormalization-group methods. Only 4 critical coordinates of the vapor-liquid critical point are needed in the (pressure, temperature, molecular volume) phase surface of xenon.

  18. Supernova neutrino physics with xenon dark matter detectors: A timely perspective

    CERN Document Server

    Lang, Rafael F; Reichard, Shayne; Selvi, Marco; Tamborra, Irene

    2016-01-01

    Dark matter detectors that utilize liquid xenon have now achieved tonne-scale targets, giving them sensitivity to all flavours of supernova neutrinos via coherent elastic neutrino-nucleus scattering. Considering for the first time a realistic detector model, we simulate the expected supernova neutrino signal for different progenitor masses and nuclear equations of state in existing and upcoming dual-phase liquid xenon experiments. We show that the proportional scintillation signal (S2) of a dual-phase detector allows for a clear observation of the neutrino signal and guarantees a particularly low energy threshold, while the backgrounds are rendered negligible during the supernova burst. XENON1T (XENONnT and LZ; DARWIN) experiments will be sensitive to a supernova burst up to 25 (35; 65) kpc from Earth at a significance of more than 5 sigma, observing approximately 35 (123; 704) events from a 27 solar-mass supernova progenitor at 10 kpc. Moreover, it will be possible to measure the average neutrino energy of a...

  19. Liquid-purity monitor for the LUX-ZEPLIN dark matter search

    Science.gov (United States)

    Manalaysay, Aaron; Lux-Zeplin Collaboration

    2016-03-01

    The LUX-ZEPLIN (LZ) experiment will be the first liquid-xenon (LXe) dark matter search to feature a multi-tonne fiducial target. Drawing on the lessons learned in the LUX and ZEPLIN experiments, this next step will probe dark-matter candidates with unprecedented sensitivity. As these LXe detectors have grown larger, so too has the distance over which ionization electrons (from particle interactions) must be drifted through the liquid. Because of this, even minute levels of electronegative impurities can significantly attenuate the ionization signal, and must therefore be closely monitored. I will present the concept of a liquid-purity monitor which uses new and novel techniques, including state-of-the-art UV LEDs and low-work-function materials, and will measure levels of impurities in LZ's liquid circulation line in real time. This device will provide vital supplemental data to the roughly weekly in-situ purity measurements carried out within the detector's active volume, will greatly improve the resolution of the ionization channel in this detector, and will yield instant feedback in response to changing detector conditions.

  20. Optically enhanced production of metastable xenon

    CERN Document Server

    Hickman, G T; Pittman, T B

    2016-01-01

    Metastable states of noble gas atoms are typically produced by electrical discharge techniques or "all-optical" excitation methods. Here we combine electrical discharges with optical pumping to demonstrate "optically enhanced" production of metastable xenon (Xe*). We experimentally measure large increases in Xe* density with relatively small optical control field powers. This technique may have applications in systems where large metastable state densities are desirable.

  1. Monte Carlo calculation of ion, electron, and photon spectra of xenon atoms in x-ray free-electron laser pulses

    CERN Document Server

    Son, Sang-Kil; 10.1103/PhysRevA.85.063415

    2013-01-01

    When atoms and molecules are irradiated by an x-ray free-electron laser (XFEL), they are highly ionized via a sequence of one-photon ionization and relaxation processes. To describe the ionization dynamics during XFEL pulses, a rate equation model has been employed. Even though this model is straightforward for the case of light atoms, it generates a huge number of coupled rate equations for heavy atoms like xenon, which are not trivial to solve directly. Here, we employ the Monte Carlo method to address this problem and we investigate ionization dynamics of xenon atoms induced by XFEL pulses at a photon energy of 4500 eV. Charge state distributions, photo-/Auger electron spectra, and fluorescence spectra are presented for x-ray fluences of up to $10^{13}$ photons/$\\mu$m$^2$. With the photon energy of 4500 eV, xenon atoms can be ionized up to +44 through multiphoton absorption characterized by sequential one-photon single-electron interactions.

  2. Results from a Calibration of XENON100 Using a Source of Dissolved Radon-220

    CERN Document Server

    Aprile, E; Agostini, F; Alfonsi, M; Amaro, F D; Anthony, M; Arneodo, F; Barrow, P; Baudis, L; Bauermeister, B; Benabderrahmane, M L; Berger, T; Breur, P A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Butikofer, L; Calven, J; Cardoso, J M R; Cervantes, M; Cichon, D; Coderre, D; Colijn, A P; Conrad, J; Cussonneau, J P; Decowski, M P; dePerio, P; DiGangi, P; DiGiovanni, A; Diglio, S; Duchovni, E; Eurin, G; Fei, J; Ferella, A D; Fieguth, A; Franco, D; Fulgione, W; Rosso, A Gallo; Galloway, M; Gao, F; Garbini, M; Geis, C; Goetzke, L W; Grandi, L; Greene, Z; Grignon, C; Hasterok, C; Hogenbirk, E; Itay, R; Kaminsky, B; Kessler, G; Kish, A; Landsman, H; Lang, R F; Lellouch, D; Levinson, L; LeCalloch, M; Lin, Q; Lindemann, S; Lindner, M; Lopes, J A M; Manfredini, A; Maris, I; Undagoitia, T Marrodan; Masbou, J; Massoli, F V; Masson, D; Mayani, D; Meng, Y; Messina, M; Micheneau, K; Miguez, B; Molinario, A; Murra, M; Naganoma, J; Ni, K; Oberlack, U; Orrigo, S E A; Pakarha, P; Pelssers, B; Persiani, R; Piastra, F; Pienaar, J; Piro, M -C; lante, G P; Priel, N; Rauch, L; Reichard, S; Reuter, C; Rizzo, A; Rosendahl, S; Rupp, N; Saldanha, R; dosSantos, J M F; Sartorelli, G; Scheibelhut, M; Schindler, S; Schreiner, J; Schumann, M; Lavina, L Scotto; Selvi, M; Shagin, P; Shockley, E; Silva, M; Simgen, H; Sivers, M v; Stein, A; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C; Upole, N; Wang, H; Wei, Y; Weinheimer, C; Wulf, J; Ye, J; Zhang, Y

    2016-01-01

    A Rn-220 source is deployed on the XENON100 dark matter detector in order to address the challenges in calibration of tonne-scale liquid noble element detectors. We show that the Pb-212 beta emission can be used for low-energy electronic recoil calibration in searches for dark matter. The isotope spreads throughout the entire active region of the detector, and its activity naturally decays below background level within a week after the source is closed. We find no increase in the activity of the troublesome Rn-222 background after calibration. Alpha emitters are also distributed throughout the detector and facilitate calibration of its response to Rn-222. Using the delayed coincidence of Rn-220/Po-216, we map for the first time the convective motion of particles in the XENON100 detector. Additionally, we make a competitive measurement of the half-life of Po-212, t = 293.9+-(1.0)+-(0.6) ns.

  3. High performance liquid chromatography time of flight electrospray ionization mass spectrometry for quantification of sesquiterpenes in Chrysanthemi indici Flos active extract

    Science.gov (United States)

    Fu, Ling; Wang, Pan; Sun, Yiqun; Wang, Yangyang; Zhao, Jing; Ye, Yuting; Zhang, Yanbin; Bi, Yuefeng

    2015-01-01

    Background: Chrysanthemi indici Flos, a traditional herbal medicine is used to clearing heat–toxicity, removing the liver fire, and improving eyesight. In our preliminary work, an active extract of CTC in C. An indici Flos with anti-hepatitis B virus and liver protective activity was found by HepG2.2.1.5 test and experiment of protein synthesis in mice's injured liver. In this work, we aimed to study the active faction CTC further by qualitative and quantitative analysis method. Materials and Methods: High performance liquid chromatography time of flight electrospray ionization mass spectrometry (HPLC TOF ESI-MS) analysis method of the CTC was established. Cumambrin A and angeloylcumambrin B in CTC were analyzed by high performance liquid chromatography-ultraviolet-evaporative light scattering detector (HPLC-UV-ELSD) analysis methods. A binary gradient elution program was conducted for chromatographic separation with acetonitrile (A) and ultrapure water (B) as follows: 0–10 min, 42–46% A; 10–20 min, 46–55% A; 20–25 min, 55–60% A; and 25–35 min, 60–75% A. The column temperature and UV wavelength were set at 30°C and 205 nm. Result: Ten constituents including (3R, 5R, 6S, 7S, 10R)-7-(2-hydroxy-2-propyl)-10-methyl-4-methyleneperhy, dronaphthal-ene-3, 5, 6-triol acetone solvate; (+)-edusmance-4, (14)-ene-11, 13-diol; linarin; luteolin; apigenin; tricin; 5, 3’,4’- trimethyl-6,7-dimethoxy flavones; cumambrin A; acacetin; and angeloylcumambrin B in CTC were identified by HPLC TOF ESI-MS. The contents of sesquiterpenes in CTC were decreased by storing years. Conclusions: The results showed that both UV and ELSD methods were feasible, accurate, and the determination results were in good consistency. The contents of two sesquiterpenes decreased with storing years. Two sesquiterpenes could be used as quality control for C. indici flos CTC. PMID:26600718

  4. Simultaneous determination of hair cortisol, cortisone and DHEAS with liquid chromatography-electrospray ionization-tandem mass spectrometry in negative mode.

    Science.gov (United States)

    Chen, Zheng; Li, Jifeng; Zhang, Jing; Xing, Xue; Gao, Wei; Lu, Zuhong; Deng, Huihua

    2013-06-15

    The present study aimed to develop a novel method for simultaneous assay of cortisol, cortisone and dehydroepiandrosterone sulfate (DHEAS) in human hair. The method was based on liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) in negative mode. Analytes were extracted from 20-mg hair incubated in 1ml of methanol for 5 days. 100μl non-SPE supernatant of the incubation solution was utilized in LC-MS/MS analysis. The liquid chromatography separation was performed on a reversed-phase C18 column with a mobile phase of 80:20 (v:v) methanol and deionized water containing 0.1% formic acid. The use of ESI in negative mode and the use of a small volume of the incubation solution significantly improved assay sensitivity. The linear range was 5-250pg/mg for cortisol and cortisone, and 5-500pg/mg for DHEAS. The limit of detection was 2pg/mg for the three analytes in hair. The coefficients of variation for intra-day and inter-day assay were less than 10%. The method was applied to determine the three analytes mentioned above of hair samples from 103 participants. The results indicated that there was no significant effect of age and education level on the hair cortisol, cortisone and DHEAS levels. The simple treatment procedure developed in the present study may facilitate simultaneous measurement of more steroids in hair. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Identification and quantification of the major constituents in Egyptian carob extract by liquid chromatography–electrospray ionization-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Asmaa Ibrahim Owis

    2016-01-01

    Full Text Available Background: Carob - Ceratonia siliqua L., commonly known as St John's-bread or locust bean, family Fabaceae - is one of the most useful native Mediterranean trees. There is no data about the chromatography methods performed by high performance liquid chromatography (HPLC for determining polyphenols in Egyptian carob pods. Objective: To establish a sensitive and specific liquid chromatography–electrospray ionization (ESI-tandem mass spectrometry (MSn methodology for the identification of the major constituents in Egyptian carob extract. Materials and Methods: HPLC with diode array detector and ESI-mass spectrometry (MS was developed for the identification and quantification of phenolic acids, flavonoid glycosides, and aglycones in the methanolic extract of Egyptian C. siliqua. The MS and MSn data together with HPLC retention time of phenolic components allowed structural characterization of these compounds. Peak integration of ions in the MS scans had been used in the quantification technique. Results: A total of 36 compounds were tentatively identified. Twenty-six compounds were identified in the negative mode corresponding to 85.4% of plant dry weight, while ten compounds were identified in the positive mode representing 16.1% of plant dry weight, with the prevalence of flavonoids (75.4% of plant dry weight predominantly represented by two methylapigenin-O-pentoside isomers (20.9 and 13.7% of plant dry weight. Conclusion: The identification of various compounds present in carob pods opens a new door to an increased understanding of the different health benefits brought about by the consumption of carob and its products.

  6. Ultra-high-performance liquid chromatography electrospray ionization tandem mass spectrometry for accurate analysis of glycerophospholipids and sphingolipids in drug resistance tumor cells.

    Science.gov (United States)

    Li, Lin; Wang, Linlin; Shangguan, Dihua; Wei, Yanbo; Han, Juanjuan; Xiong, Shaoxiang; Zhao, Zhenwen

    2015-02-13

    Glycerophospholipids and sphingolipids are important signaling molecules which are involved in many physiological and pathological processes. Here we reported an effective method for accurate analysis of these lipids by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The methanol method was adopted for extraction of lipids due to its simplicity and high efficiency. It was found that two subclasses of sphingolipids, sulfatide (ST) and cerebroside (CB), were heat labile, so a decreased temperature in the ion source of MS might be necessary for these compounds analysis. In addition, it was found that the isobaric interferences were commonly existent, for example, the m/z of 16:0/18:1 PC containing two (13)C isotope being identical to that of 16:0/18:0 PC determined by a unit mass resolution mass spectrometer; therefore, a baseline separation of interferential species was required to maintain selectivity and accuracy of analysis. In this work, an ultra-high-performance liquid chromatography (UHPLC)-based method was developed for separation of interferential species. Moreover, in order to deal with the characteristics of different polarity and wide dynamic range of glycerophospholipids and sphingolipids in biological systems, three detecting conditions were combined together for comprehensive and rational analysis of glycerophospholipids and sphingolipids. The method was utilized to profile glycerophospholipids and sphingolipids in drug resistant tumor cells. Our results showed that many lipids were significantly changed in drug resistant tumor cells compared to paired drug sensitive tumor cells. This is a systematic report about the isobaric interferences and heat labile compounds interferences when analyzing glycerophospholipids and sphingolipids by ESI-MS/MS, which aids in ruling out one potential source of systematic error to ensure the accuracy of analysis.

  7. Determination of selected antibiotics in the Victoria Harbour and the Pearl River, South China using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Xu Weihai [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangzhou 510640 (China); School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510250 (China); Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Post-graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang Gan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangzhou 510640 (China)]. E-mail: zhanggan@gig.ac.cn; Zou Shichun [School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510250 (China); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Liu Yuchun [School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510250 (China)

    2007-02-15

    Nine selected antibiotics in the Victoria Harbour of Hong Kong and the Pearl River at Guangzhou, South China, were analyzed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. The results showed that the concentrations of antibiotics were mainly below the limit of quantification (LOQ) in the marine water of Victoria Harbour. However, except for amoxicillin, all of the antibiotics were detected in the Pearl River during high and low water seasons with the median concentrations ranging from 11 to 67 ng/L, and from 66 to 460 ng/L, respectively; and the concentrations in early spring were about 2-15 times higher than that in summer with clearer diurnal variations. It was suggested that the concentrations of antibiotics in the high water season were more affected by wastewater production cycles due to quick refreshing rate, while those in the low water season may be more sensitive to the water column dynamics controlled by tidal processes in the river. - Antibiotics were found at high concentrations in an urban reach of Pearl River in southern China with contrast diurnal variations between the high and low water seasons.

  8. Ultra pressure liquid chromatography-negative electrospray ionization mass spectrometry determination of twelve halobenzoquinones at ng/L levels in drinking water.

    Science.gov (United States)

    Huang, Rongfu; Wang, Wei; Qian, Yichao; Boyd, Jessica M; Zhao, Yuli; Li, Xing-Fang

    2013-05-01

    We report here the characterization of twelve halobenzoquinones (HBQs) using electrospray ionization (ESI) high resolution quadrupole time-of-flight mass spectrometry. The high resolution negative ESI spectra of the twelve HBQs formed two parent ions, [M + H(+) + 2e(-)], and the radical M(-•). The intensities of these two parent ions are dependent on their chemical structures and on instrumental parameters such as the source temperature and flow rate. The characteristic ions of the HBQs were used to develop an ultra pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. At the UPLC flow rate (400 μL/min) and under the optimized ESI conditions, eleven HBQs showed the stable and abundant transitions [M + H(+) + 2e(-)] → X(-) (X(-) representing Cl(-), Br(-), or I(-)), while dibromo-dimethyl-benzoquinone (DBDMBQ) showed only the transition of M(-•) → Br(-). The UPLC efficiently separates all HBQs including some HBQ isomers, while the MS/MS offers exquisite limits of detection (LODs) at subng/mL levels for all HBQs except DBDMBQ. Combined with solid phase extraction (SPE), the method LOD is down to ng/L. The results from analysis of authentic samples demonstrated that the SPE-UPLC-MS/MS method is reliable, fast, and sensitive for the identification and quantification of the twelve HBQs in drinking water.

  9. Trace analysis of selected hormones and sterols in river sediments by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Matić, Ivana; Grujić, Svetlana; Jauković, Zorica; Laušević, Mila

    2014-10-17

    In this paper, development and optimization of new LC-MS method for determination of twenty selected hormones, human/animal and plant sterols in river sediments were described. Sediment samples were prepared using ultrasonic extraction and clean up with silica gel/anhydrous sodium sulphate cartridge. Extracts were analyzed by liquid chromatography-linear ion trap-tandem mass spectrometry, with atmospheric pressure chemical ionization. The optimized extraction parameters were extraction solvent (methanol), weight of the sediment (2 g) and time of ultrasonic extraction (3× 10 min). Successful chromatographic separation of hormones (estriol and estrone, 17α- and 17β-estradiol) and four human/animal sterols (epicoprostanol, coprostanol, α-cholestanol and β-cholestanol) that have identical fragmentation reactions was achieved. The developed and optimized method provided high recoveries (73-118%), low limits of detection (0.8-18 ng g(-1)) and quantification (2.5-60 ng g(-1)) with the RSDs generally lower than 20%. Applicability of the developed method was confirmed by analysis of six river sediment samples. A widespread occurrence of human/animal and plant sterols was found. The only detected hormone was mestranol in just one sediment sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. A highly specific and sensitive quantification analysis of the sterols in silkworm larvae by high performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Igarashi, Fumihiko; Hikiba, Juri; Ogihara, Mari H; Nakaoka, Takayoshi; Suzuki, Minoru; Kataoka, Hiroshi

    2011-12-15

    The biochemical quantification of sterols in insects has been difficult because only small amounts of tissues can be obtained from insect bodies and because sterol metabolites are structurally related. We have developed a highly specific and sensitive quantitative method for determining of the concentrations of seven sterols-7-dehydrocholesterol, desmosterol, cholesterol, ergosterol, campesterol, stigmasterol, and β-sitosterol-using a high performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (HPLC/APCI-MS/MS). The sterols were extracted from silkworm larval tissues using the Bligh and Dyer method and were analyzed using HPLC/APCI-MS/MS with selected reaction monitoring, using cholesterol-3,4-(13)C(2) as an internal standard. The detection limits of the method were between 12.1 and 259 fmol. The major sterol in most silkworm larval tissues was cholesterol, whereas only small quantities of the dietary sterols were detected. Thus, a simple, sensitive, and specific method was successfully developed for the quantification of the sterol concentrations in each tissue of an individual silkworm larva. This method will be a useful tool for investigating to molecular basis of sterol physiology in insects, facilitating the quantification of femtomole quantities of sterols in biological samples. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. High performance liquid chromatography (HPLC fingerprints and primary structure identification of corn peptides by HPLC-diode array detection and HPLC-electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Chi Wang

    2016-01-01

    Full Text Available Corn peptides (CPs are reported to have many biological functions, such as facilitating alcohol metabolism, antioxidation, antitumor, antihypertension, and hepatoprotection. To develop a method for quality control, the high-performance liquid chromatography (HPLC system was applied. Twenty-eight common peaks were found in all the CPs of corn samples from Enshi, China, based on which, a fingerprinting chromatogram was established for use in quality control in future research. Subsequently, the major chemical constituents of these common peaks were identified respectively using the HPLC-diode-array detection electrospray ionization tandem mass spectrometry (DAD-ESI-MS/MS system, and 48 peptide fractions were determined ultimately. This was the first time for the majority of these peptides to be reported, and many of them contained amino acids of glutamine (Q, L and A, which might play an important role in the exhibition of the bioactivities of CPs. Many peptides had a similar primary structure to the peptides which had been proven to be bioactive such as facilitating alcohol metabolism, scavenging free radicals, and inhibiting lipid peroxidation. This systematical analysis of the primary structure of CPs facilitated subsequent studies on the relationship between the structures and functions, and could accelerate holistic research on CPs.

  12. On-line high-performance liquid chromatography-fluorescence detection-electrospray ionization-mass spectrometry profiling of human milk oligosaccharides derivatized with 2-aminoacridone.

    Science.gov (United States)

    Galeotti, Fabio; Coppa, Giovanni V; Zampini, Lucia; Maccari, Francesca; Galeazzi, Tiziana; Padella, Lucia; Santoro, Lucia; Gabrielli, Orazio; Volpi, Nicola

    2012-11-01

    A high-resolution normal-phase high-performance liquid chromatography-fluorescence detection-electrospray ionization-mass spectrometry separation and structural characterization of the main oligosaccharides along with lactose from human milk samples is described. A total of 22 commercially available oligosaccharides were fluorotagged with 2-aminoacridone and separated on an amide column and identified on the basis of their retention times and mass spectra. Derivatized species having mass lower than approximately 800 to 900 exhibited mainly [M-H](-1) anions, oligomers with mass up to approximately 1000 to 1100 were represented by both [M-H](-1) and [M-2H](-2) anions, and oligomers greater than approximately 1200 to 1300 were characterized by a charge state of -3. Furthermore, the retention times were directly related to the glycans' molecular mass. Human milk samples from the four groups of donors (Se±/Le±) were analyzed for their composition and amount of free oligosaccharides after rapid and simple prepurification and derivatization steps also in the presence of lactose in high content. This analytical approach enabled us to perform the determination of species not detected by traditional techniques, such as sialic acid, as well as of species present in low content easily mistaken with other peaks. Finally, labeled human milk oligosaccharides were analyzed without any interference from excess fluorophore or interference from proteins, peptides, salts, and other impurities normally present in this complex biological fluid.

  13. Determination of Phenolic Content in Different Barley Varieties and Corresponding Malts by Liquid Chromatography-diode Array Detection-Electrospray Ionization Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Daniel O. Carvalho

    2015-08-01

    Full Text Available A simple and reliable method for the simultaneous determination of nine phenolic compounds in barley and malted barley was established, using liquid chromatography-diode array detection-electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI-MS/MS. The phenolic compounds can be easily detected with both systems, despite significant differences in sensitivity. Concentrations approximately 180-fold lower could be achieved by mass spectrometry analysis compared to diode array detection, especially for the flavan-3-ols (+-catechin and (−-epicatechin, which have poor absorptivity in the UV region. Malt samples were characterized by higher phenolic content comparing to corresponding barley varieties, revealing a significant increase of the levels of (+-catechin and (−-epicatechin during the malting process. Moreover, the industrial malting is responsible for modification on the phenolic profile from barley to malt, namely on the synthesis or release of sinapinic acid and epicatechin. Accordingly, the selection of the malting parameters, as well as the barley variety plays an important role when considering the quality and antioxidant stability of beer.

  14. Simultaneous determination of urinary parabens, bisphenol A, triclosan, and 8-hydroxy-2'-deoxyguanosine by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Ren, Lu; Fang, Jianzhang; Liu, Guihua; Zhang, Jianqing; Zhu, Zhou; Liu, Honghe; Lin, Kai; Zhang, Huimin; Lu, Shaoyou

    2016-04-01

    A simple and fast method was developed for the simultaneous determination of five parabens, bisphenol A (BPA), triclosan (TCS), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urine using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The solid-phase extraction (SPE) procedure, chromatographic conditions, and MS/MS parameters were optimized to achieve maximum sensitivity and accuracy for the analytes. The validation results showed that the correlation coefficients (R (2)) and recoveries ranged from 0.999 to 1 and 83.9 to 109.9 %, respectively, and the intra-day and inter-day precisions (relative standard deviation, RSD) were within the range of 1.3-8.5 % and 1.3-9.0 %, respectively. The limits of detection for the analytes ranged from 0.001 to 0.05 μg/L. The method was successfully employed to determine parabens, BPA, TCS, and 8-OHdG in urine samples from school students in Guangzhou, China. The results showed that methyl, ethyl, n-propyl parabens, BPA, TCS, and 8-OHdG were frequently detected in urine samples. n-Butyl and benzyl parabens were only detected in a part of the samples due to their low concentrations in urine.

  15. Identification of indigoid dyes in natural organic pigments used in historical art objects by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry.

    Science.gov (United States)

    Puchalska, Maria; Połeć-Pawlak, Kasia; Zadrozna, Irmina; Hryszko, Helena; Jarosz, Maciej

    2004-12-01

    Pigments are among the most important components of historical paintings and textiles and their nature provides the unique character of color. They can be divided into two main groups: inorganic and organic, extracted from plants or animals. Their identification is a necessary stage in the conservation of art objects. Reversed-phase liquid chromatography with electrospray ionization mass spectrometry (ESI-MS) and UV/visible spectrophotometric methods were elaborated for the identification of indigoid (indigo, indirubin, isoindigo, isoindirubin) color components of natural dyestuffs and their natural or synthetic precursors (indican, isatin, indoxyl, 2-indolinone). ES-MS offers detection limits in the range 0.03-5.00 microg ml(-1) for the color compounds examined. The method developed made it possible to identify indigo and its isomers in genuine Indian indigo, indigo from woad and Tyrian Purple. It was applied to the identification of natural dyes on fiber from a 19th century Japanese tapestry, 'Cranes in the landscape'. A procedure based on freezing and grinding of a sample before the extraction of dyes from the textile was developed. The components of the extract obtained were identified after acidic hydrolysis as indigotin and methylene blue.

  16. High throughput screening various abused drugs and metabolites in urine by liquid chromatography-heated electrospray ionization/tandem mass spectrometry.

    Science.gov (United States)

    Chen, Chung-Yu; Shen, Chien-Chun; Yang, Tzung-Jie; Chang, Yan-Zin; Lee, Maw-Rong

    2009-02-15

    An integrated method of liquid chromatography-heated electrospray ionization/tandem mass spectrometry was evaluated for high throughput screening of various abused drugs in urine. Chromatographic analysis was performed on a C18 reverse phase column using a linear gradient of 10mM ammonium acetate containing 0.1% formic acid-methanol as mobile phase and the total separation time was 7 min. A simple and rapid sample preparation method used was by passing urine samples through a 0.22 microm PVDF syringe filter. The detection limits of the studied abused drugs in urine were from 0.6 ng mL(-1) (ketamine) to 9.0 ng mL(-1) (norcodeine). According to the results, the linear range was from 1 to 1200 ng mL(-1) with relative standard deviation (R.S.D.s) value below 14.8% (intra-day) and 24.6% (inter-day). The feasibility of applying the proposed method to determine various abused drugs in real samples was examined by analyzing urine samples from drug-abused suspects. The abused drugs including ketamines and amphetamines were detected in suspected urine samples. The results demonstrate the suitability of LC-HESI-MS/MS for high throughput screening of the various abused drugs in urine.

  17. Development of a liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous analysis of intact glucosinolates and isothiocyanates in Brassicaceae seeds and functional foods.

    Science.gov (United States)

    Franco, P; Spinozzi, S; Pagnotta, E; Lazzeri, L; Ugolini, L; Camborata, C; Roda, A

    2016-01-08

    A new high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry method for the simultaneous determination of glucosinolates, as glucoraphanin and glucoerucin, and the corresponding isothiocyanates, as sulforaphane and erucin, was developed and applied to quantify these compounds in Eruca sativa defatted seed meals and enriched functional foods. The method involved solvent extraction, separation was achieved in gradient mode using water with 0.5% formic acid and acetonitrile with 0.5% formic acid and using a reverse phase C18 column. The electrospray ion source operated in negative and positive mode for the detection of glucosinolates and isothiocyanates, respectively, and the multiple reaction monitoring (MRM) was selected as acquisition mode. The method was validated following the ICH guidelines. Replicate experiments demonstrated a good accuracy (bias%<10%) and precision (CV%<10%). Detection limits and quantification limits are in the range of 1-400ng/mL for each analytes. Calibration curves were validated on concentration ranges from 0.05 to 50μg/mL. The method proved to be suitable for glucosinolates and isothiocyanates determination both in biomasses and in complex matrices such as food products enriched with glucosinolates, or nutraceutical bakery products. In addition, the developed method was applied to the simultaneous determination of glucosinolates and isothiocyanates in bakery product enriched with glucosinolates, to evaluate their thermal stability after different industrial processes from cultivation phases to consumer processing.

  18. Direct identification of phenolic constituents in Boldo Folium (Peumus boldus Mol.) infusions by high-performance liquid chromatography with diode array detection and electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Simirgiotis, M J; Schmeda-Hirschmann, G

    2010-01-22

    A very simple and direct method was developed for the qualitative analysis of polyphenols in boldo (Peumus boldus Mol., Monimiaceae) leaves infusions by high-performance liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionization tandem mass spectrometry (HPLC-MS(n)). The phenolic constituents identified in infusions of the crude drug Boldo Folium were mainly proanthocyanidins and flavonol glycosides. In the infusions, 41 compounds were detected in male and 43 compounds in female leaf samples, respectively. Nine quercetin glycosides, eight kaempferol derivatives, nine isorhamnetin glycosides, three phenolic acids, one caffeoylquinic acid glycoside and twenty one proanthocyanidins were identified by HPLC-DAD and ESI-MS for the first time in the crude drug. Isorhamnetin glucosyl-di-rhamnoside was the most abundant flavonol glycoside in the male boldo sample, whereas isorhamnetin di-glucosyl-di-rhamnoside was the main phenolic compound in female boldo leaves infusion. The results suggest that the medicinal properties reported for this popular infusion should be attributed not only to the presence of catechin and boldine but also to several phenolic compounds with known antioxidant activity. The HPLC fingerprint obtained can be useful in the authentication of the crude drug Boldo Folium as well as for qualitative analysis and differentiation of plant populations in the tree distribution range. Copyright 2009 Elsevier B.V. All rights reserved.

  19. Chemical analysis of raw and processed Fructus arctii by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kunming Qin

    2014-01-01

    Full Text Available Background: In traditional Chinese medicine (TCM, raw and processed herbs are used to treat the different diseases. Fructus Arctii, the dried fruits of Arctium lappa l. (Compositae, is widely used in the TCM. Stir-frying is the most common processing method, which might modify the chemical compositions in Fructus Arctii. Materials and Methods: To test this hypothesis, we focused on analysis and identification of the main chemical constituents in raw and processed Fructus Arctii (PFA by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry. Results: The results indicated that there was less arctiin in stir-fried materials than in raw materials. however, there were higher levels of arctigenin in stir-fried materials than in raw materials. Conclusion: We suggest that arctiin reduced significantly following the thermal conversion of arctiin to arctigenin. In conclusion, this finding may shed some light on understanding the differences in the therapeutic values of raw versus PFA in TCM.

  20. A simple and selective method for the measurement of azadirachtin and related azadirachtoid levels in fruits and vegetables using liquid chromatography electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Sarais, Giorgia; Caboni, Pierluigi; Sarritzu, Erika; Russo, Mariateresa; Cabras, Paolo

    2008-05-14

    Neem-based insecticides containing azadirachtin and related azadirachtoids are widely used in agriculture. Here, we report an analytical method for the rapid and accurate quantification of the insecticide azadirachtin A and B and other azadirachtoids such as salannin, nimbin, and their deacetylated analogues on tomatoes and peaches. Azadirachtoids were extracted from fruits and vegetables with acetonitrile. Using high-performance liquid chromatography/electrospray ionization tandem mass spectrometer, azadirachtoids were selectively detected monitoring the multiple reaction transitions of sodium adduct precursor ions. For azadirachtin A, calibration was linear over a working range of 1-1000 microg/L with r > 0.996. The limit of detection and limit of quantification for azadirachtin A were 0.4 and 0.8 microg/kg, respectively. The presence of interfering compounds in the peach and tomato extracts was evaluated and found to be minimal. Because of the linear behavior, it was concluded that the multiple reaction transitions of sodium adduct ions can be used for analytical purposes, that is, for the identification and quantification of azadirachtin A and B and related azadirachtoids in fruit and vegetable extracts at trace levels.

  1. Evaluation of relative transmitted dose for a step and shoot head and neck intensity modulated radiation therapy using a scanning liquid ionization chamber electronic portal imaging device.

    Science.gov (United States)

    Mohammadi, Mohammad; Bezak, Eva

    2012-01-01

    The dose delivery verification for a head and neck static intensity modulated radiation therapy (IMRT) case using a scanning liquid ionization chamber electronic portal imaging device (SLIC-EPID) was investigated. Acquired electronic portal images were firstly converted into transmitted dose maps using an in-house developed method. The dose distributions were then compared with those calculated in a virtual EPID using the Pinnacle(3) treatment planning system (TPS). Using gamma evaluation with the ΔD(max) and DTA criteria of 3%/2.54 mm, an excellent agreement was observed between transmitted dose measured using SLIC-EPID and that calculated by TPS (gamma score approximately 95%) for large MLC fields. In contrast, for several small subfields, due to SLIC-EPID image blurring, significant disagreement was found in the gamma results. Differences between EPID and TPS dose maps were also observed for several parts of the radiation subfields, when the radiation beam passed through air on the outside of tissue. The transmitted dose distributions measured using portal imagers such as SLIC-EPID can be used to verify the dose delivery to a patient. However, several aspects such as accurate calibration procedure and imager response under different conditions should be taken into the consideration. In addition, SLIC-EPID image blurring is another important issue, which should be considered if the SLIC-EPID is used for clinical dosimetry verification.

  2. Evaluation of relative transmitted dose for a step and shoot head and neck intensity modulated radiation therapy using a scanning liquid ionization chamber electronic portal imaging device

    Directory of Open Access Journals (Sweden)

    Mohammad Mohammadi

    2012-01-01

    Full Text Available The dose delivery verification for a head and neck static intensity modulated radiation therapy (IMRT case using a scanning liquid ionization chamber electronic portal imaging device (SLIC-EPID was investigated. Acquired electronic portal images were firstly converted into transmitted dose maps using an in-house developed method. The dose distributions were then compared with those calculated in a virtual EPID using the Pinnacle3 treatment planning system (TPS. Using gamma evaluation with the DDmax and DTA criteria of 3%/2.54 mm, an excellent agreement was observed between transmitted dose measured using SLIC-EPID and that calculated by TPS (gamma score approximately 95% for large MLC fields. In contrast, for several small subfields, due to SLIC-EPID image blurring, significant disagreement was found in the gamma results. Differences between EPID and TPS dose maps were also observed for several parts of the radiation subfields, when the radiation beam passed through air on the outside of tissue. The transmitted dose distributions measured using portal imagers such as SLIC-EPID can be used to verify the dose delivery to a patient. However, several aspects such as accurate calibration procedure and imager response under different conditions should be taken into the consideration. In addition, SLIC-EPID image blurring is another important issue, which should be considered if the SLIC-EPID is used for clinical dosimetry verification.

  3. Determination of terbuthylazine and desethylterbuthylazine in human urine and hair samples by eletrospray ionization-liquid chromatography/triple quadrupole mass spectrometry.

    Science.gov (United States)

    Mercadante, Rosa; Polledri, Elisa; Fustinoni, Silvia

    2012-08-01

    Terbuthylazine (TBA) is a widely applied herbicide and an environmental contaminant. Following its use, humans, such as agricultural workers and rural residents, may be exposed. An isotope-dilution liquid chromatography coupled to electrospray-tandem mass spectrometry method for the determination of TBA, and its metabolite desethylterbuthylazine (DET) in human urine and hair was developed and validated. Under the optimised conditions, analytes were extracted from urine using a solid phase cartridge or from hair by sonication in methanol. Analytes were separated using a C18 reversed-phase chromatographic column and quantified, after positive ionization using a heated electrospray source, by a triple quadrupole mass detector in the selected reaction monitoring mode. Validation showed linear dynamic ranges up to 100 μg/L or 5.00 ng/mg hair, inter- and intra-run precisions <7%, and accuracies within 12% of spiked concentrations. Limits of quantification were 0.25 μg/L in urine and 0.01 ng/mg hair for both TBA and DET. Matrix effect evaluation showed that the isotope dilution approach allowed for the control of bias sources. TBA and DET were determined in specimens of agriculture workers exposed to TBA using the validated method. Hair samples contained TBA levels in the low nanogram per milligram range, and urine samples contained DET levels in the low microgram per liter range. Conversely, TBA levels in urine samples and DET levels in hair samples were always below the limit of quantification.

  4. Determination of catechins and caffeine in proposed green tea standard reference materials by liquid chromatography-particle beam/electron ionization mass spectrometry (LC-PB/EIMS).

    Science.gov (United States)

    Castro, Joaudimir; Pregibon, Tara; Chumanov, Kristina; Marcus, R Kenneth

    2010-10-15

    Presented here is the quantitative analysis of green tea NIST standard reference materials (SRMs) via liquid chromatography-particle beam/electron ionization mass spectrometry (LC-PB/EIMS). Three different NIST green tea standard reference materials (SRM 3254 Camellia sinesis Leaves, SRM 3255 C. sinesis Extract and SRM 3256 Green Tea-containing Oral Dosage Form) are characterized for the content of caffeine and a series of catechin species (gallic acid, catechin, epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate (EGCG)). The absolute limits of detection for caffeine and the catechin species were determined to be on the nanogram level. A reversed-phase chromatographic separation of the green tea reference materials was carried out on a commercial C(18) column using a gradient of water (containing 0.1% TFA) and 2:1 methanol:acetonitrile (containing 0.1%TFA) at 0.9mLmin(-1) and an analysis time of 50min. Quantification of caffeine and the catechin species was carried out using the standard addition and internal standard methods, with the latter providing appreciable improvements in precision and recovery.

  5. Identification and quantification of antitumor thioproline and methylthioproline in Korean traditional foods by a liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Kim, Sun Hyo; Kim, Hyun-Ji; Shin, Ho-Sang

    2014-11-01

    A liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometric method (LC-APCI-MS/MS) has been developed for the sensitive determination of antitumor thioproline and methylthioproline from fermented foods. Thioproline and methylthioproline were derivatized in one step with ethyl chloroformate at room temperature. These compounds were identified and quantified in various traditional Korean fermented foods by LC-APCI-MS/MS. The concentration range of thioproline of each food was found for doenjang (0.011-0.032mg/kg), gochujang (0.010-0.038mg/kg), and ganjang (0.010-0.038mg/kg). Those of methylthioproline of each food was found for doenjang (0.098-0.632mg/kg), gochujang (0.015-0.112mg/kg), and ganjang (0.023-1.468mg/kg). A prolonged aging time leads to an increase in both the thioproline and methylthioproline contents, suggesting that the storage time plays a key role in the formation of thioproline and methylthioproline in Korean traditional foods. The results here suggest that thioproline and methylthioproline are related to the biological activities of traditional Korean fermented foods.

  6. Selective and rapid determination of raltegravir in human plasma by liquid chromatography-tandem mass spectrometry in the negative ionization mode

    Institute of Scientific and Technical Information of China (English)

    Ajay Gupta; Swati Guttikar; Priyanka A. Shah; Gajendra Solanki; Pranav S. Shrivastav; Mallika Sanyal

    2015-01-01

    A selective and rapid high-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the quantification of raltegravir using raltegravir-d3 as an internal standard (IS). The analyte and IS were extracted with methylene chloride and n-hexane solvent mixture from 100 mL human plasma. The chromatographic separation was achieved on a Chromolith RP-18e endcapped C18 (100 mm ? 4.6 mm) column in a run time of 2.0 min. Quantitation was performed in the negative ionization mode using the transitions of m/z 443.1-316.1 for raltegravir and m/z 446.1-319.0 for IS. The linearity of the method was established in the concentration range of 2.0–6000 ng/mL. The mean extraction recovery for raltegravir and IS was 92.6% and 91.8%, respectively, and the IS-normalized matrix factors for raltegravir ranged from 0.992 to 0.999. The application of this method was demonstrated by a bioequivalence study on 18 healthy subjects.

  7. Antioxidant activities and liquid chromatography with electrospray ionization tandem mass spectrometry characterization and quantification of the polyphenolic contents of Rumex nervosus Vahl leaves and stems.

    Science.gov (United States)

    Desta, Kebede Taye; Lee, Won Sup; Lee, Sung Joong; Kim, Yun-Hi; Kim, Gon-Sup; Lee, Soo Jung; Kim, Soo Taek; Abd El-Aty, A M; Warda, Mohamad; Shin, Ho-Chul; Shim, Jae Han; Shin, Sung Chul

    2016-04-01

    In the present study, four compounds, viz. chlorogenic acid, catechin, orientin, and apigenin-O-acetylglycoside among 18 polyphenol compounds (17 flavonoids and one hydroxycinnamic acid derivative) were characterized for the first time in Rumex nervosus leaves and stems by using liquid chromatography with electrospray ionization tandem mass spectrometry. Method validation in terms of determination coefficient, limits of detection, and quantification were ≥ 0.9979, 0.68-1.61, and 2.27-5.38 mg/L, respectively. Accuracy, expressed as percent recovery for two spiking levels (10 and 50 mg/L), were in the range 78.9-110.6% with the exception of caffeic acid. The relative standard deviations were 1-17%. The total polyphenol content was higher by approximately two times in the leaf (1073 mg/kg fresh sample) than in the stem (519.86 mg/kg fresh sample). The antioxidant effects increased in a dose-dependent manner, and the scavenging activities, investigated by measuring 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity, ferrous ions chelating activity, superoxide anion radical scavenging activity, and ferric reducing antioxidant power activity, were significant (p < 0.05) using low concentrations of the leaf extract. Overall, the present study suggests that different parts of R. nervosus have great potential for producing a range of extracts with potential applications in medicine.

  8. High-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry analysis of Radix Saposhnikoviae for metabolomic research.

    Science.gov (United States)

    Li, Yue-Yue; Wang, Xin-Xia; Zhao, Liang; Zhang, Hai; Lv, Lei; Zhou, Gui-chen; Chai, Yi-Feng; Zhang, Guo-Qing

    2013-02-01

    In this study, metabolite profiling of Radix Saposhnikoviae from different geographical locations was performed using high-performance liquid chromatography-electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOFMS) and multivariate statistical analysis technique. Principle component analysis (PCA) of the data shows that these samples could be roughly separated into three groups: Guan Fangfeng, Kou Fangfeng and Chuan Fangfeng. The potential chemical markers were discovered through the loading plot of PCA. Based on accurate mass measurements and subsequent fragment ions of TOFMS after in-source collision induced dissociation, as well as matching of empirical molecular formulae with those of published components in the in-house chemical library, 10 potential markers, such as 4'-O-glucosyl-5-O-methylvisamminol, cimifugin, prim-O-glucosylcimifugin and 3'-O-angeloylhammaudol, were tentatively identified and partially verified by the available reference standards. The results of this study indicate that it is an effective and novel approach to identify traditional Chinese medicine (TCM) from different sources, and that performing quantity determination of corresponding marker compounds could optimize the quality control of TCM.

  9. Chemical analysis of raw and processed Fructus arctii by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry

    Science.gov (United States)

    Qin, Kunming; Liu, Qidi; Cai, Hao; Cao, Gang; Lu, Tulin; Shen, Baojia; Shu, Yachun; Cai, Baochang

    2014-01-01

    Background: In traditional Chinese medicine (TCM), raw and processed herbs are used to treat the different diseases. Fructus Arctii, the dried fruits of Arctium lappa l. (Compositae), is widely used in the TCM. Stir-frying is the most common processing method, which might modify the chemical compositions in Fructus Arctii. Materials and Methods: To test this hypothesis, we focused on analysis and identification of the main chemical constituents in raw and processed Fructus Arctii (PFA) by high-performance liquid chromatography/diode array detection-electrospray ionization-mass spectrometry. Results: The results indicated that there was less arctiin in stir-fried materials than in raw materials. however, there were higher levels of arctigenin in stir-fried materials than in raw materials. Conclusion: We suggest that arctiin reduced significantly following the thermal conversion of arctiin to arctigenin. In conclusion, this finding may shed some light on understanding the differences in the therapeutic values of raw versus PFA in TCM. PMID:25422559

  10. Identification of 3′,4′-Dimethoxy Flavonol-3-β-d-Glucopyranoside Metabolites in Rats by Liquid Chromatography-Electrospray Ionization Ion Trap Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Yuan Zhu

    2016-04-01

    Full Text Available A method using liquid chromatography-electrospray ionization ion trap mass spectrometry was established for the identification of metabolites in feces, urine and bile in rats after oral administration of 3′,4′-dimethoxy flavonol-3-β-d-glucopyranoside (abbreviated DF3G. Seven metabolites in rat feces, urine and bile were firstly identified on the basis of their MS fragmentation behaviors. Three metabolites were identified in the feces, 6 in the urine and 2 in the bile, which suggested that demethylation, deglycosylation and deglycosylation followed by glucuronide conjugation were the major metabolic pathways for DF3G in vivo. Hydrolyzation might be the first step in the absorption and metabolism of DF3G. The possible metabolic pathway was proposed for the first time. The established method was simple, reliable and sensitive, revealing that it could be used to rapidly screen and identify the structures of metabolites of DF3G to better understand its metabolism in vivo.

  11. Selective and rapid determination of raltegravir in human plasma by liquid chromatography–tandem mass spectrometry in the negative ionization mode

    Directory of Open Access Journals (Sweden)

    Ajay Gupta

    2015-04-01

    Full Text Available A selective and rapid high-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the quantification of raltegravir using raltegravir-d3 as an internal standard (IS. The analyte and IS were extracted with methylene chloride and n-hexane solvent mixture from 100 µL human plasma. The chromatographic separation was achieved on a Chromolith RP-18e endcapped C18 (100 mm×4.6 mm column in a run time of 2.0 min. Quantitation was performed in the negative ionization mode using the transitions of m/z 443.1→316.1 for raltegravir and m/z 446.1→319.0 for IS. The linearity of the method was established in the concentration range of 2.0–6000 ng/mL. The mean extraction recovery for raltegravir and IS was 92.6% and 91.8%, respectively, and the IS-normalized matrix factors for raltegravir ranged from 0.992 to 0.999. The application of this method was demonstrated by a bioequivalence study on 18 healthy subjects.

  12. Determination of bevantolol in human plasma using liquid chromatography-electrospray ionization tandem mass spectrometry and its application to a bioequivalence study.

    Science.gov (United States)

    Ren, Li; Wang, Zheng; Lou, Yiceng; Zheng, Lu; Zheng, Heng; Yin, Chunping

    2014-05-15

    A liquid chromatography-electrospray ionization tandem mass spectrometry method was established and validated for the determination of bevantolol in human plasma using propranolol as the internal standard. The optimal chromatographic behavior of bevantolol and propranolol was achieved on a Welch Ultimate XB-C18 column (5 μm, 150 mm × 2.1mm, Maryland, USA) with a mobile phase of acetonitrile-water (40:60, v/v) containing 10mM ammonium acetate and 0.1% formic acid. The mass spectrometer was operated in selected reaction monitoring mode using the transition m/z 346.1>165.1 for bevantolol and m/z 260.3>116.1 for propranolol. Sample preparation was carried out through protein precipitation with acetonitrile. The calibration curves were linear over the range of 5.00-1,000 ng/ml. The intra- and inter-day precisions were less than 6.7% and 6.6%, respectively. This method was successfully applied to the bioequivalence study of two kinds of bevantolol hydrochloride tablets in 24 Chinese male volunteers in fasting and postprandial experiment.

  13. Characterization of eight terpenoids from tissue cultures of the Chinese herbal plant, Tripterygium wilfordii, by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Su, Ping; Cheng, Qiqing; Wang, Xiujuan; Cheng, Xiaoqing; Zhang, Meng; Tong, Yuru; Li, Fei; Gao, Wei; Huang, Luqi

    2014-09-01

    In this study, a reliable method for analysis and identification of eight terpenoids in tissue cultures of Tripterygium wilfordii has been established using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS). Our study indicated that sterile seedlings, callus cultures and cell-suspension cultures can rapidly increase the amount of biological materials. HPLC-ESI-MS was used to identify terpenoids from the extracts of these tissue cultures. Triptolide, triptophenolide, celastrol and wilforlide A were unambiguously determined by comparing the retention times, UV spectral data, and mass fragmentation behaviors with those of the reference compounds. Another four compounds were tentatively identified as triptonoterpenol, triptonoterpene, 22β-hydroxy-3-oxoolean-12-en-29-oic acid and wilforlide B, based on their UV and mass spectrometry spectra. The quantitative analysis showed that all three materials contain triptolide, triptophenolide, celastrol, wilforlide A, and the contents of the four compounds in the cell-suspension cultures were 53.1, 240, 129 and 964 µg/g, respectively, which were at least 2.0-fold higher than these in the sterile seedlings and callus cultures. Considering the known pharmacological activity of triptolide and celastrol, we recommend the cell-suspension cultures as biological materials for future studies, such as clinical and toxicological studies. The developed method was validated by the evaluation of its precision, linearity, detection limits and recovery, and it was successfully used to identify and quantify the terpenoids in the tissue cultures.

  14. Extraction and preconcentration of residual solvents in pharmaceuticals using dynamic headspace-liquid phase microextraction and their determination by gas chromatography-flame ionization detection.

    Science.gov (United States)

    Farajzadeh, Mir Ali; Dehghani, Hamideh; Yadeghari, Adeleh; Khoshmaram, Leila

    2017-02-01

    The present study describes a microextraction and determination method for analyzing residual solvents in pharmaceutical products using dynamic headspace-liquid phase microextraction technique followed by gas chromatography-flame ionization detection. In this method dimethyl sulfoxide (μL level) placed into a GC liner-shaped extraction vessel is used as a collection/extraction solvent. Then the liner is exposed to the headspace of a vial containing the sample solution. The effect of different parameters influencing the microextraction procedure including collection/extraction solvent type and its volume, ionic strength, extraction time, extraction temperature and concentration of NaOH solution used in dissolving the studied pharmaceuticals are investigated and optimized. Under the optimum extraction conditions, the method showed wide linear ranges between 0.5 and 5000 mg L(-1) . The other analytical parameters were obtained in the following ranges: enrichment factors 240-327, extraction recoveries 72-98% and limits of detection 0.1-0.8 mg L(-1) in solution and 0.6-3.2 μg g(-1) in solid. Relative standard deviations for the extraction of 100 mg L(-1) of each analyte were obtained in the ranges of 4-7 and 5-8% for intra-day (n = 6) and inter-day (n = 4) respectively. Finally the target analytes were determined in different samples such as erythromycin, azithromycin, cefalexin, amoxicillin and co-amoxiclav by the proposed method.

  15. Separation of small molecular peptides with the same amino acid composition but different sequences by high performance liquid chromatography-electrospray ionization-mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Peptidomics has emerged as a new discipline in recent years. Mass spectrometry (MS) is the most universal and efficient tool for structure identification of proteins and peptides. However,there is a limitation for the identification of peptides with the same amino acid composition but different se-quences because these peptides have identical mass spectra of molecular ions. This paper presents a high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method for the separation of small molecular peptides with the same amino acid composition but dif-ferent sequences. Two tripeptides of Gly-Ser-Phe and Gly-Phe-Ser were used as a model sample. The separation behavior has been investigated and the separation conditions have been optimized. Under the optimum conditions,good repeatability was achieved. The developed method could provide a helpful reference for the separation of other peptides with the same amino acid composition but different sequences in the study of proteomics and peptidomics.

  16. A novel high-performance liquid chromatography-electron spray ionization-mass spectrometry method for simultaneous determination of guggulsterones, piperine and gallic acid in Triphala guggulu

    Directory of Open Access Journals (Sweden)

    Ganesh Muguli

    2015-01-01

    Full Text Available "Triphalaguggulu0" is an important Ayurvedic formulation comprising of Guggulu, that is, Commiphora wightii (Arn. Bhandari as a base wherein powdered fruits of triphala, that is, Phyllanthus emblica L., Terminalia bellirica (Gaertn. Roxb and Terminalia chebula Retz, along with powdered fruit of Piper longum L. are compounded. This polyherbal preparation has been strongly recommended in chronic inflammation, piles, and fistula. However, due to the complexity of compound formulation standardization of commercial products is challenging. In the present communication marker-based standardization of "Triphalaguggulu" preparation using gallic acid (for triphala, piperine (for P. longum L. and guggulsterones (for guggulu is reported. These compounds of diverse chemistry were successfully separated on a Waters HR-C18 column by isocratic elution with methanol and water (80:20 v/v as mobile phase at the flow rate of 1.0 mL/min coupled with photodiode array detector. These optimal chromatographic conditions were used for simultaneous quantification of gallic acid, guggulsterones (E and Z and piperine in commercial samples by high-performance liquid chromatography-electron spray ionization-mass spectrometry and method was validated as per ICH guidelines.

  17. Quantification of fudosteine in human plasma by high-performance liquid chromatography-electrospray ionization mass spectrometry employing precolumn derivatization with 9-fluorenylmethyl chloroformate.

    Science.gov (United States)

    Xu, Fengguo; Zhang, Zunjian; Jiao, Haoyan; Tian, Yuan; Zhang, Beibei; Chen, Yun

    2006-05-01

    This paper describes a novel method for the sensitive and selective determination of fudosteine in human plasma. The method involves a derivatization step with 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer and detection based on high-performance liquid chromatography-electrospray ionization mass spectrometry (LC/ESI/MS). After acetonitrile-induced protein precipitation of plasma samples, fudosteine was derivatized with FMOC-Cl, then extracted by ethyl acetate, evaporated, reconstituted and injected using an LC/ESI/MS instrument. Separation was achieved using an ODS column and isocratic elution. Excellent linearity was obtained for the entire calibration range from 0.05 to 20 microg/ml. Validation assays of the lower limit of quantification (LLOQ) as well as for the intra- and inter-batch precision and accuracy met the international acceptance criteria for bioanalytical method validation. Using the developed analytical method, fudosteine could be detected for the first time in human plasma with a low limit of detection (LLOD) of 0.03 microg/ml. The proposed method has been successfully applied to study the pharmacokinetics of fudosteine in healthy Chinese volunteers after single and multiple oral administration.

  18. Direct analysis of psychoactive tryptamine and harmala alkaloids in the Amazonian botanical medicine ayahuasca by liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    McIlhenny, Ethan H; Pipkin, Kelly E; Standish, Leanna J; Wechkin, Hope A; Strassman, Rick; Barker, Steven A

    2009-12-18

    A direct injection/liquid chromatography-electrospray ionization-tandem mass spectrometry procedure has been developed for the simultaneous quantitation of 11 compounds potentially found in the increasingly popular Amazonian botanical medicine and religious sacrament ayahuasca. The method utilizes a deuterated internal standard for quantitation and affords rapid detection of the alkaloids by a simple dilution assay, requiring no extraction procedures. Further, the method demonstrates a high degree of specificity for the compounds in question, as well as low limits of detection and quantitation despite using samples for analysis that had been diluted up to 200:1. This approach also appears to eliminate potential matrix effects. Method bias for each compound, examined over a range of concentrations, was also determined as was inter- and intra-assay variation. Its application to the analysis of three different ayahuasca preparations is also described. This method should prove useful in the study of ayahuasca in clinical and ethnobotanical research as well as in forensic examinations of ayahuasca preparations.

  19. Salt Tolerance Enhancement of Liquid Chromatography-Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Using Matrix Additive Methylenediphosphonic Acid

    Science.gov (United States)

    Ohta, Yuki; Iwamoto, Shinichi; Kawabata, Shin-ichirou; Tanimura, Ritsuko; Tanaka, Koichi

    2014-01-01

    Mass spectrometry (MS) is a highly sensitive analytical technique that is often coupled with liquid chromatography (LC). However, some buffering salts used in LC (e.g., phosphate and tris(hydroxymethyl)aminomethane (Tris)) are incompatible with MS since they cause ion-source contamination and signal suppression. In this study, we examined salt tolerance of MALDI and applied a matrix additive methylenediphosphonic acid (MDPNA) to reduce salt-induced signal suppression. MDPNA significantly improved the salt tolerance of MALDI-MS. Using ammonium formate buffer at pH 5.0, the effective range of buffering salt concentration in MALDI-MS using MDPNA was estimated up to 250 mM. MDPNA reduced signal suppression caused by buffering salts at pH 4.0 to 8.0. We observed that MDPNA effectively worked over a wide range of buffer conditions. MDPNA was further applied to hydrophilic interaction chromatography (HILIC) and chromatofocusing-MALDI-MS. As a result, the analytes in the eluent containing high-concentration salts were detected with high sensitivity. Thus, our study provides simple and fast LC-MALDI-MS analysis technique not having strict limitation of buffering condition in LC by using matrix additive MDPNA. PMID:26819873

  20. Analysis of phenolic compounds in commercial dried grape pomace by high-performance liquid chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Ramirez-Lopez, Lina M; DeWitt, Christina A M

    2014-09-01

    By-products obtained from winemaking processes still contain large amounts of phenolic compounds, especially phenolic acids, flavanols, flavonols, stilbenes, and flavonoids. Enzymatic hydrolysis was used for determination and characterization of phenolic acids, flavanols, flavonols, and stilbenes. Characterization of the flavonoids was achieved using acid hydrolysis with 0.1% hydrochloric acid. In addition, organic solvents as 50% methanol, 70% methanol, 50% acetone, 0.01% pectinase, and 100% petroleum ether were also evaluated. Reversed phase high-performance liquid chromatography (RP-HPLC) with diode array detector was used to identify phenolic compounds. Internal standard quantification was implemented using a five points of the UV-visible absorption data collected at the wavelength of maximum absorbance. A total of 16 phenolic compounds were determined. The content differed from 1.19 to 1124 mg kg(-1). Outcomes from HPLC study showed that gallic acid, (+) catechin hydrate, and (-) epicatechin gallate were the major phenolic compounds presented in the sample. Malvidin and pelargonidin 3-O-glucoside were the major anthocyanins monoglucosides.

  1. Monte Carlo model for electron degradation in xenon gas

    CERN Document Server

    Mukundan, Vrinda

    2016-01-01

    We have developed a Monte Carlo model for studying the local degradation of electrons in the energy range 9-10000 eV in xenon gas. Analytically fitted form of electron impact cross sections for elastic and various inelastic processes are fed as input data to the model. Two dimensional numerical yield spectrum, which gives information on the number of energy loss events occurring in a particular energy interval, is obtained as output of the model. Numerical yield spectrum is fitted analytically, thus obtaining analytical yield spectrum. The analytical yield spectrum can be used to calculate electron fluxes, which can be further employed for the calculation of volume production rates. Using yield spectrum, mean energy per ion pair and efficiencies of inelastic processes are calculated. The value for mean energy per ion pair for Xe is 22 eV at 10 keV. Ionization dominates for incident energies greater than 50 eV and is found to have an efficiency of 65% at 10 keV. The efficiency for the excitation process is 30%...

  2. Relative dosimetry of photon beam of 6 MV with a liquid ionization chamber; Dosimetria relativa de un haz de fotones de 6 MV con una camara de ionizacion liquida

    Energy Technology Data Exchange (ETDEWEB)

    Benitez Villegas, E. M.; Casado Villalon, F. J.; Martin-Cueto, J. A.; Caudepon Moreno, F.; Garcia Pareja, S.; Galan Montenegro, P.

    2011-07-01

    The increasing use of reduced size fields in the special techniques of treatment generates regions with high dose gradients. It therefore requires the use of detectors that present high spatial resolution. The aim of this study is to compare the dosimetric measurements obtained with a liquid ionization chamber PTW MicroLion recently acquired with other commonly used detectors for a photon beam of 6 MV linear electron accelerator Varian 600DBX.

  3. An improved measurement of electron-ion recombination in high-pressure xenon gas

    CERN Document Server

    Serra, L; Álvarez, V; Borges, F I G; Camargo, M; Cárcel, S; Cebrián, S; Cervera, A; Conde, C A N; Dafni, T; Díaz, J; Esteve, R; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Gehman, V M; Goldschmidt, A; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Hauptman, J; Morata, J A Hernando; Herrera, D C; Irastorza, I G; Labarga, L; Laing, A; Liubarsky, I; Lopez-March, N; Lorca, D; Losada, M; Luzón, G; Marí, A; Martín-Albo, J; Martínez-Lema, G; Martínez, A; Miller, T; Monrabal, F; Monserrate, M; Monteiro, C M B; Mora, F J; Moutinho, L M; Vidal, J Muñoz; Nebot-Guinot, M; Nygren, D; Oliveira, C A B; Pérez, J; Aparicio, J L Pérez; Querol, M; Renner, J; Ripoll, L; Rodríguez, A; Rodríguez, J; Santos, F P; Santos, J M F dos; Shuman, D; Simón, A; Sofka, C; Toledo, J F; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Villar, J A; Webb, R; White, J T; Yahlali, N

    2014-01-01

    We report on results obtained with the NEXT-DEMO prototype of the NEXT-100 high-pressure xenon gas time projection chamber (TPC), exposed to an alpha decay calibration source. Compared to our previous measurements with alpha particles, an upgraded detector and improved analysis techniques have been used. We measure event-by-event correlated fluctuations between ionization and scintillation due to electron-ion recombination in the gas, with correlation coeffcients between -0.80 and -0.56 depending on the drift field conditions. By combining the two signals, we obtain a 2.8 % FWHM energy resolution for 5.49 MeV alpha particles and a measurement of the optical gain of the electroluminescent TPC. The improved energy resolution also allows us to measure the specific activity of the radon in the gas due to natural impurities. Finally, we measure the average ratio of excited to ionized atoms produced in the xenon gas by alpha particles to be $0.561\\pm 0.045$, translating into an average energy to produce a primary s...

  4. SU-E-T-460: Impact of the LINAC Repetition Rate On a High-Resolution Liquid Ionization Chamber Array for Patient-Specific QA

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S; Driewer, J; Zheng, D; Lei, Y; Zhang, Q; Zhu, X; Li, S; Enke, C; Zhou, S [University of Nebraska Medical Center, Omaha, NE (United States); Xu, B [The Fujian Medical University Union Hospital, Fu Zhou, Fu Jian (China)

    2015-06-15

    Purpose: The purpose of this study is to investigate the LINAC repetition-rate (dose-rate) dependence of OCTAVIUS 1000SRS liquid ionization chamber (LIC) array for patient specific QA of SRT plans delivered with flattening-filter-free (FFF) beams. Methods: 1) The repetition-rate dependence of 1000SRS was measured in a phantom constructed with 5-cm solid water above and below the array for build-up and backscatter. A 0.3cc calibrated ion chamber was also placed along the central axis 2.3cm below the center chamber of the array for normalizing LINAC output fluctuation. The signals from the center chamber of the array under different repetition rates in the range of 400–2400 MU/min for 6xFFF and 10xFFF beams on a Varian TrueBeamSTx LINAC, normalized by the independent chamber readings, were analyzed for the array response dependence on repetition rates. 2) Twelve Step-and-shoot IMRS QA plans (6xFFF and 10xFFF) were delivered to the array under different repetition rates for analysis and comparison. 3) The absolute doses measured by the center chamber were compared to measurements using an independent ionization chamber with the identical setup, taken as the gold standard. 4) The correction factors based on the actual delivery repetition rate were applied to the measurements, and the results were compared again to the gold standard. Results: 1) The 1000SRS array exhibited repetition-rate dependence for FFF beams, up to 5% for 6xFFF and 10% for 10xFFF; 2) The array showed clinically-acceptable repetition-rate dependence for regular flattened beams; 3) This repetition-rate dependence significantly affected the measurement accuracy, thereby affecting IMRS QA results; 4) By applying an empirical repetition-rate correction, the corrected measurements agreed better with the gold standard ion chamber measurements. Conclusion: OCTAVIUS 1000SRS LIC array exhibited considerable repetition-rate dependence for FFF beams, which will affect the accuracy of the absolute QA

  5. Simultaneous determination of Eleutheroside B and Eleutheroside E in rat plasma by high performance liquid chromatography-electrospray ionization mass spectrometry and its application in a pharmacokinetic study.

    Science.gov (United States)

    Ma, Bo; Zhang, Qi; Liu, Yinhui; Li, Jing; Xu, Qiuyu; Li, Xiaotian; Yang, Xiaojing; Yao, Di; Sun, Jingjing; Cui, Guangbo; Ying, Hanjie

    2013-02-15

    Eleutheroside B and Eleutheroside E, two kinds of the major bioactive saponins of Eleutherococcus senticosus, play a pivotal role in biologic activity. In this study, a specific and sensitive high performance liquid chromatography-electrospray ionization-tandem mass spectrometry method (HPLC-MS/MS) was developed and validated for simultaneous determination of Eleutheroside B and Eleutheroside E in rat plasma. The analytes were extracted from rat plasma via a simple protein precipitation procedure with methanol and polygonin was used as internal standard. Chromatographic separation was achieved on a C18 column using a gradient elution program with acetonitrile and water containing 0.1% ammonium hydroxide solution as the mobile phase, with a flow rate of 0.2mL/min. The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reactions monitoring (MRM) mode in a negative ion mode via electrospray ionization (ESI). The transition monitored were m/z 371 [M-H](-)→209 for Eleutheroside B, m/z 741[M-H](-)→579 for Eleutheroside E and m/z 389[M-H](-)→277 for internal standard. Linear calibration curves were obtained in the concentration range of 1-2000ng/mL for both (Eleutheroside B and Eleutheroside E), with a lower limit of quantification of 1ng/mL. Extraction recovery was over 80% in plasma. The intra- and inter-day precision (RSD) values were below 12% and accuracy (RE) was -2.80 to 5.70% at three QC levels for both. The assay was successfully applied to study pharmacokinetics behavior in rats after oral and intravenous administration of the single substances (Eleutheroside B and Eleutheroside E). And further research was performed by comparing the difference in pharmacokinetic behavior between the single substances and an aqueous extract of E. senticosus after oral administration. Significant difference in pharmacokinetic characteristics between the single substances and an aqueous extract was found in rat, which would be beneficial for

  6. Cryogenic gaseous photomultipliers and liquid hole- multipliers: advances in THGEM-based sensors for future noble-liquid TPCs

    Science.gov (United States)

    Arazi, L.; Coimbra, A. E. C.; Erdal, E.; Israelashvili, I.; Rappaport, M. L.; Shchemelinin, S.; Vartsky, D.; dos Santos, J. M. F.; A, Breskin

    2015-11-01

    Dual-phase noble-liquid TPCs are presently the most sensitive instruments for direct dark matter detection. Scaling up existing ton-scale designs to the multi-ton regime may prove to be technologically challenging. This includes both large-area coverage with affordable high-QE UV-photon detectors, and maintaining high precision in measuring the charge and light signals of rare events with keV-scale energy depositions. We present our recent advances in two complementary approaches to these problems: large-area cryogenic gaseous photomultipliers (GPM) for UV-photon detection, and liquid-hole multipliers (LHM) that provide electroluminescence light in response to ionization electrons and primary scintillation photons, using perforated electrodes immersed within the noble liquid. Results from a 10 cm diameter GPM coupled to a dual-phase liquid- xenon TPC demonstrate the feasibility of recording - for the first time - both primary (“S1”) and secondary (“S2”) scintillation signals, over a very broad dynamic range. The detector, comprising a triple-THGEM structure with CsI on the first element, has been operating stably at 180 K with gains larger than 105; it provided high single-photon detection efficiency - in the presence of massive alpha-particle induced S2 signals; S1 scintillation signals were recorded with time resolutions of 1.2 ns (RMS). Results with the LHM operated in liquid xenon yielded large photon gains, with a pulse-height resolution of 11% (RMS) for alpha-particle induced S2 signals. The detector response was stable over several months. The response of the S2 signals to rapid changes in pressure lead to the conclusion that the underlying mechanism for S2 light is electroluminescence in xenon bubbles trapped below the immersed THGEM electrode. Both studies have the potential of paving the way towards new designs of dual- and single-phase noble-liquid TPCs that could simplify the conception of future multi-ton detectors of dark matter and other rare

  7. Xenon poisoning calculation code for miniature neutron source reactor (MNSR)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In line with the actual requirements and based upon the specific char acteristics of MNSR, a revised point-reactor model was adopted to model MNSR's xenon poisoning. The corresponding calculation code, MNSRXPCC (Xenon Poison ing Calculation Code for MNSR), was developed and tested by the Shanghai MNSR data.

  8. Analysis of the XENON100 dark matter search data

    NARCIS (Netherlands)

    Aprile, E.; et al., [Unknown; Alfonsi, M.; Decowski, M.P.

    2014-01-01

    The XENON100 experiment, situated in the Laboratori Nazionali del Gran Sasso, aims at the direct detection of dark matter in the form of weakly interacting massive particles (WIMPs), based on their interactions with xenon nuclei in an ultra low background dual-phase time projection chamber. This pap

  9. Solubilities of krypton and xenon in dichlorodifluoromethane

    Energy Technology Data Exchange (ETDEWEB)

    Shaffer, J.H.; Shockley, W.E.; Greene, C.W.

    1984-07-01

    The solubility behavior of krypton and xenon in dichlorodifluoromethane was investigated for the Consolidated Fuel Reprocessing Program (CFRP) in support of the fluorocarbon absorption process. The solubility data derived from solute radioisotopes had uncertainties of approx. 0.1%. Values for Henry's law constants were initially determined under equilibrium conditions at infinite solute dilution. Based on these results, the study was extended to finite solute concentrations. Nonidealities in the two binary systems were expressed as gas phase fugacity coefficients for each solute at 10/sup 0/ intervals over the range -30 to +50/sup 0/C. 22 references, 4 figures, 2 tables.

  10. A xenon gas purity monitor for EXO

    CERN Document Server

    Dobi, A; Herrin, S; Odian, A; Prescott, C Y; Rowson, P C; Ackerman, N; Aharmin, B; Auger, M; Barbeau, P S; Barry, K; Benitez-Medina, C; Breidenbach, M; Cook, S; Counts, I; Daniels, T; DeVoe, R; Dolinski, M J; Donato, K; Fairbank, W; Farine, J; Giroux, G; Gornea, R; Graham, K; Gratta, G; Green, M; Hagemann, C; Hall, K; Hallman, D; Hargrove, C; Karelin, A; Kaufman, L J; Kuchenkov, A; Kumar, K; Lacey, J; Leonard, D S; LePort, F; Mackay, D; MacLellan, R; Mong, B; Diez, M Montero; Muller, A R; Neilson, R; Niner, E; O'Sullivan, K; Piepke, A; Pocar, A; Pushkin, K; Rollin, E; Sinclair, D; Slutsky, S; Stekhanov, V; Twelker, K; Voskanian, N; Vuilleumier, J -L; Wichoski, U; Wodin, J; Yang, L; Yen, Y -R

    2011-01-01

    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.

  11. A pulse generator for xenon lamps

    CERN Document Server

    Janata, E

    2002-01-01

    A pulse generator is described, which enhances the analyzing light emitted from a xenon lamp as used in kinetic photospectrometry experiments. The lamp current is increased to 600 A for a duration of 3 ms; the current is constant within +-0.2% during a time interval of 2 ms. Because of instabilities of the lamp arc during pulsing, the use of the enhanced light source is limited to measuring times up to 500 mu s. The enhancement in light intensity depends on the wavelength and amounts to more than 400-fold in the UV-region.

  12. A pulse generator for xenon lamps

    Science.gov (United States)

    Janata, E.

    2002-10-01

    A pulse generator is described, which enhances the analyzing light emitted from a xenon lamp as used in kinetic photospectrometry experiments. The lamp current is increased to 600 A for a duration of 3 ms; the current is constant within ±0.2% during a time interval of 2 ms. Because of instabilities of the lamp arc during pulsing, the use of the enhanced light source is limited to measuring times up to 500 μs. The enhancement in light intensity depends on the wavelength and amounts to more than 400-fold in the UV-region.

  13. Progress in characterization of the Photomultiplier Tubes for XENON1T Dark Matter Experiment

    CERN Document Server

    Lyashenko, Alexey

    2015-01-01

    We report on the progress in characterization of the Hamamatsu model R11410-21 Photomultiplier tubes (PMTs) for XENON1T dark matter experiment. The absolute quantum efficiency (QE) of the PMT was measured at low temperatures down to -110 $^0$C (a typical the PMT operation temperature in liquid xenon detectors) in a spectral range from 154.5 nm to 400 nm. At -110 $^0$C the absolute QE increased by 10-15\\% at 175 nm compared to that measured at room temperature. A new low power consumption, low radioactivity voltage divider for the PMTs is being developed. The measurement results showed that the PMT with the current version of the divider demonstrated a linear response (within 5\\%) down to 5$\\cdot$10$^4$ photoelectrons at a rate of 200 Hz. The radioactive contamination induced by the PMT and the PMT voltage divider materials satisfies the requirements for XENON1T detector not to exceed a total radioactive contamination in the detector of 0.5 evts/year/1tonn. Most of the PMTs received from the manufacturer showe...

  14. Studies of selenium and xenon in inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bricker, T.

    1994-07-27

    Since its development, inductively coupled plasma mass spectrometry (ICP-MS) has been a widely used analytical technique. ICP-MS offers low detection limits, easy determination of isotope ratios, and simple mass spectra from analyte elements. ICP-MS has been successfully employed for many applications including geological, environmental, biological, metallurgical, food, medical, and industrial. One specific application important to many areas of study involves elemental speciation by using ICP-MS as an element specific detector interfaced to liquid chromatography. Elemental speciation information is important and cannot be obtained by atomic spectrometric methods alone which measure only the total concentration of the element present. Part 1 of this study describes the speciation of selenium in human serum by size exclusion chromatography (SEC) and detection by ICP-MS. Although ICP-MS has been widely sued, room for improvement still exists. Difficulties in ICP-MS include noise in the background, matrix effects, clogging of the sampling orifice with deposited solids, and spectral interference caused by polyatomic ions. Previous work has shown that the addition of xenon into the central channel of the ICP decreases polyatomic ion levels. In Part 2 of this work, a fundamental study involving the measurement of the excitation temperature is carried out to further understand xenon`s role in the reduction of polyatomic ions. 155 refs.

  15. Ultrasound-assisted dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry in negative chemical ionization mode for the determination of polybrominated diphenyl ethers in water.

    Science.gov (United States)

    Zhang, Qian; Liang, Tao; Guan, Lili

    2013-04-01

    A simple and economical method for the determination of eight polybrominated diphenyl ethers (BDE-28, 47, 99, 100,153,154,183, and 209) in water was developed. This method involves the use of ultrasound-assisted dispersive liquid-liquid microextraction combined with GC-MS in negative chemical ionization mode. Various parameters affecting the extraction efficiency, including the type and volume of extraction and dispersive solvents, salt concentration, extraction time, and ultrasonic time, were investigated. A volume of 1.0 mL of acetone (dispersive solvent) containing 10 μL tetrachloroethylene (extraction solvent) was injected into 5.0 mL of water samples and then emulsified by ultrasound for 2.0 min to produce the cloudy solution. Under the optimal condition, the enrichment factors for the eight PBDEs were varied from 845- to 1050-folds. Good linearity was observed in the range of 1.0-200 ng L(-1) for BDE-28, 47, 99, and 100; 5.0-200 ng L(-1) for BDE-153, 154, and 183; and 5.0-500 ng L(-1) for BDE-209. The RSD values were in the range of 2.5-8.4% (n = 5) and the LODs ranged from 0.40 to 2.15 ng L(-1) (S/N = 3). The developed method was applied for the determination of eight BPDEs in the river and lake water samples, and the mean recoveries at spiking levels of 5.0 and 50.0 ng L(-1) were in the range of 70.6-105.1%.

  16. Monitoring of four dipyrone metabolites in communal wastewater by solid phase extraction liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Gyenge-Szabó, Zsuzsa; Szoboszlai, Norbert; Frigyes, Dávid; Záray, Gyula; Mihucz, Victor G

    2014-03-01

    Liquid chromatography quadrupole time-of-flight spectrometry (LC-Q-TOF-MS), equipped with electrospray ionization (ESI), was developed for the determination of the main metabolites of dipyrone - 4-aminoantipyrine (4-AA), 4-acetylaminoantipyrine (4-AAA), 4-formylaminoantipyrine (4-FAA) and 4-methylaminoantipyrine (4-MAA) in communal wastewater after reversed-phase solid phase extraction (SPE) in the low to several μg/l concentration range. Samples originated from conventional wastewater treatment plant (WWTP) using activated sewage sludge as well as from a pilot-scale WWTP operating in mixed mode (activated sewage sludge and cascade biofilms reactors with biofilms growing on fix beds and roots of greenhouse plants). Results of the present study confirmed the outcomes of our previous report according to which, 4-FAA was the most persistent metabolite, while 4-AAA and 4-MAA could be determined in the highest and lowest concentration, respectively. Moreover, the study of intraday variation of the concentration of these metabolites revealed that the concentration of 4-AA, 4-AAA and 4-FAA registered a 46%-75% increase in the samples collected at noon compared to those collected at 6 AM. Chlorination did not affect considerably the removal efficiency (about 15%) of these metabolites in samples collected for 3 months consecutively before and after disinfection. Both wastewater treatment techniques efficiently removed 4-AAA (between 80 and 96%). However, in the summer season, the removal efficiency of conventional WWTP using open-air aerated tanks is lower by 30%, (on average) than in the cold season. The concentration of the investigated metabolites showed increased concentrations in the winter season confirming the intake habits of the population from this popular analgesic and antipyretic drug. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. [Determination of 49 drugs and 5 metabolites in drinking water samples using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry].

    Science.gov (United States)

    Wang, Shuo; Zhang, Xiangming; Zhang, Jing; Shao, Bing; Li, Shuming

    2015-07-01

    A method for the determination of 54 drugs in drinking water samples was developed by using ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI MS/MS). The target drugs in drinking water samples were enriched and cleaned-up by HLB solid-phase extraction (SPE) cartridges and then eluted with 5 mL methanol. The elute was collected, concentrated under a gentle stream of nitrogen gas, diluted with 0.4 mL 0.1% formic acid solution, and analyzed by UPLC-ESI MS/MS. The separation of the 54 drugs was performed on an ACQUITY UPLC™ BEH C18 column using mobile phases of 0.1% formic acid and methanol by gradient elution. The multiple reaction monitoring (MRM) mode was employed in mass spectrometry acquisition. The matrix-matched external standard calibration was used for quantitation. The results showed that the average recoveries of the drugs in ground water, tap water and surface water were 58.7%-104.4%, 53.1%-109.5%, and 50.7%-118.8%, respectively, and the corresponding relative standard deviations (RSD, n=6) were 0.3%-12.8%, 1.0%-15.5%, and 0.4%-19.3%, respectively. The method quantification limits (MQL) for target compounds were in the range of 0.002-5.000 ng/L. The developed method was applied to analyze the water samples from Beijing. The results showed that 26 drugs were detected in ground water samples.

  18. Determination of eight nitrosamines in water at the ng L(-1) levels by liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry.

    Science.gov (United States)

    Ripollés, Cristina; Pitarch, Elena; Sancho, Juan V; López, Francisco J; Hernández, Félix

    2011-09-19

    In this work, we have developed a sensitive method for detection and quantification of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMor), N-nitrosomethylethylamine (NMEA), N-nitrosopirrolidine (NPyr), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPip), N-nitroso-n-dipropylamine (NDPA) and N-nitrosodi-n-butylamine (NDBA) in drinking water. The method is based on liquid chromatography coupled to tandem mass spectrometry, using atmospheric pressure chemical ionization (APCI) in positive mode with a triple quadrupole analyzer (QqQ). The simultaneous acquisition of two MS/MS transitions in selected reaction monitoring mode (SRM) for each compound, together with the evaluation of their relative intensity, allowed the simultaneous quantification and reliable identification in water at ppt levels. Empirical formula of the product ions selected was confirmed by UHPLC-(Q)TOF MS accurate mass measurements from reference standards. Prior to LC-MS/MS QqQ analysis, a preconcentration step by off-line SPE using coconut charcoal EPA 521 cartridges (by passing 500 mL of water sample) was necessary to improve the sensitivity and to meet regulation requirements. For accurate quantification, two isotope labelled nitrosamines (NDMA-d(6) and NDPA-d(14)) were added as surrogate internal standards to the samples. The optimized method was validated at two concentration levels (10 and 100 ng L(-1)) in drinking water samples, obtaining satisfactory recoveries (between 90 and 120%) and precision (RSDwater samples: chlorinated from drinking water and wastewater treatment plants (DWTP and WWTP, respectively), wastewaters subjected to ozonation and tap waters.

  19. Liquid chromatography/negative electrospray ionization ion trap MS(2) mass spectrometry application for the determination of microcystins occurrence in Southern Portugal water reservoirs.

    Science.gov (United States)

    Rodrigues, M A; Reis, M P; Mateus, M C

    2013-11-01

    Microcystins (MCs) are toxins produced by cyanobacteria which are common organisms in the phytoplankton of eutrophic lakes, rivers and freshwater reservoirs. In the present work, a novel method of liquid chromatography-electrospray ion trap tandem mass spectrometry (LC/ESI/Ion trap-MS/MS), operated in the negative ionization mode, was developed for the analysis of these cyanotoxins. The method was applied to determine the amounts of total microcystins-LR, -YR and -RR in two water reservoirs in Southern Portugal, namely Alqueva and Beliche. A total of 30 water samples were analysed along 2011. Solid phase extraction (SPE) was used for sample cleaning-up and analyte enrichment. The extracted toxins were separated on a C18 column with a gradient of acetonitrile/water with 0.1% formic acid. Detection of microcystins was carried out using multiple reaction monitoring (MRM) in the negative polarity mode, as this method gave a higher selectivity. The MC-RR, YR and LR quantification limits were 17.9, 31.7 and 15.8 ng/L, respectively; quite below the limits recommended by WHO guidelines for drinking water (1 μg/L). Total MC highest concentrations were found in the warm months of June, July and September in Alqueva sampling sites, with concentrations of MC LR and RR ranging 17-344 and 25-212 ng/L, respectively, showing comparable results for MC-RR and LR and slightly lower concentration of MC-YR. Detected values for Beliche reservoir were below quantification limits.

  20. High performance liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry for sensitive determination of bioactive amines in donkey milk.

    Science.gov (United States)

    La Torre, Giovanna Loredana; Saitta, Marcello; Giorgia Potortì, Angela; Di Bella, Giuseppa; Dugo, Giacomo

    2010-08-06

    In the present study we report on the optimization and validation of a sensitive high performance liquid chromatography atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI-MS) method for the determination of 8 bioactive amines (histamine, tyramine, tryptamine, 2-phenylethylamine, cadaverine, putrescine, spermidine and spermine) in donkey milk samples. The method involves donkey milk pre-treatment to remove proteins and pre-column dansylation of the amines. HPLC in reversed phase mode has been used for bioactive amines separation and the operating condition of the APCI-MS system proved to be powerful and very efficient for peak assignment. The separation was accomplished in a short time with an excellent resolution for all the amine peaks. Quantification was carried out by monitoring the characteristic [M+H](+) ion of each amine derivative. The method sensitivity, linearity and repeatability were assayed with satisfactory results. The detection limits of the analysed amines ranged from 0.5 microg L(-1) to 15 microg L(-1); the highest LOD was for spermine. Also remarkably good recovery values were obtained; at the lowest spiking level (1 microg L(-1)) the percent mean recoveries ranged from 77.7 to 109.7. Furthermore, as the investigations relate to a complex matrix as donkey milk, suitable studies on matrix effect were performed. Finally, the developed and validated method was applied to analyse 13 donkey milk samples. Among the identified bioactive amines, putrescine, spermine and spermidine proved to be the main amines in donkey milk. Their concentration levels in the present study were lower than the values determined in mature human, cow and sow milk.

  1. Ultra high performance liquid chromatography- ultraviolet-electrospray ionization-micrOTOF-Q II analysis of flavonoid fractions from Jatropha tanjorensis

    Directory of Open Access Journals (Sweden)

    Arun Kallur Purushothaman

    2014-01-01

    Full Text Available Background: Jatropha tanjorensis (Euphorbiaceae an exotic traditional plant unique to Thanjavur district of Southern India also commonly called as Catholic vegetable. It has been used traditionally in decoctions for treating various ailments and as a health tonic. Objective: The objective of the present work is to study a comprehensive characterization of methanolic extract fractions using ultra high performance liquid chromatography (UHPLC+-electrospray ionization (ESI-micrOTOF-Q II and correlate their bioactivities. Materials and Methods: Phytoconstituents from J. tanjorensis leaves were extracted with methanol (MeOH followed by successive chromatography using linear gradient polar solvents system. All fractions obtained were evaluated for their chemical potential using micrOTOF-Q II techniques and identified key molecules were determined for their anticancer and anti-oxidant potential using in vitro methods. Results: Successive column chromatography of the MeOH residue yielded six fractions. Compounds such as such as C-glycosylflavones (mono-C-, di-C-, O, C-diglycosylflavones and aglycones were identified for the first time in this plant using UHPLC-ultraviolet-micrOTOF-Q II ESI and a correlation with their anticancer using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay on Ehrlich ascites cells (EAC and antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl and lipid peroxidation were studied; fraction D extract exhibited the strongest activity against cancer cell. Conclusions: LC-mass spectrometry has been successfully applied for a quick separation and identification of the major phytoconstituents. All fractions have shown potent antioxidative activity as compared to standard antioxidant 3,5-di-tert-butyl-4-hydroxytoluene. EAC cell-based cytotoxicity assay also revealed encouraging results. The antioxidant and anticancer activity determined in the present work can be attributed to the presence of flavonoids and

  2. Development of a method for comprehensive and quantitative analysis of plant hormones by highly sensitive nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Yoshihiro; Okazawa, Atsushi; Bamba, Takeshi; Kobayashi, Akio [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukusaki, Eiichiro, E-mail: fukusaki@bio.eng.osaka-u.ac.jp [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2009-08-26

    In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC-ESI-IT-MS/MS method showed ca. 5-10-fold greater sensitivity than capillary-LC-ESI-IT-MS/MS, and the detection limits (S/N = 3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (R{sup 2} values of 0.9937-1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC-ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1 mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.

  3. Profiling of triacylglycerols in plant oils by high-performance liquid chromatography-atmosphere pressure chemical ionization mass spectrometry using a novel mixed-mode column.

    Science.gov (United States)

    Hu, Na; Wei, Fang; Lv, Xin; Wu, Lin; Dong, Xu-Yan; Chen, Hong

    2014-12-01

    In this investigation, a rapid and high-throughput method for profiling of TAGs in plant oils by liquid chromatography using a single column coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry was reported. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this separation system. The phenyl-hexyl column could provide hydrophobic interactions as well as π-π interactions. Compared with two traditionally columns used in TAG separation - the C18 column and silver-ion column, this column exhibited much higher selectivity for the separation of TAGs with great efficiency and rapid speed. By comparison with a novel mix-mode column (Ag-HiSep OTS column), which can also provide both hydrophobic interactions as well as π-π interactions for the separation of TAGs, phenyl-hexyl column exhibited excellent stability. LC method using phenyl-hexyl column coupled with APCI-MS was successfully applied for the profiling of TAGs in soybean oils, peanut oils, corn oils, and sesame oils. 29 TAGs in peanut oils, 22 TAGs in soybean oils, 19 TAGs in corn oils, and 19 TAGs in sesame oils were determined and quantified. The LC-MS data was analyzed by barcodes and principal component analysis (PCA). The resulting barcodes constitute a simple tool to display differences between different plant oils. Results of PCA also enabled a clear identification of different plant oils. This method provided an efficient and convenient chromatographic technology for the fast characterization and quantification of complex TAGs in plant oils at high selectivity. It has great potential as a routine analytical method for analysis of edible oil quality and authenticity control.

  4. Simultaneous quantification of amphetamines, caffeine and ketamine in urine by hollow fiber liquid phase microextraction combined with gas chromatography-flame ionization detector.

    Science.gov (United States)

    Xiong, Jun; Chen, Jie; He, Man; Hu, Bin

    2010-08-15

    A method of hollow fiber (HF) liquid phase microextraction (LPME) combined with gas chromatography (GC)-flame ionization detection (FID) was developed for the simultaneous quantification of trace amphetamine (AP), methamphetamine (MA), methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA), caffeine and ketamine (KT) in drug abuser urine samples. The factors affecting on the extraction of six target analytes by HF-LPME were investigated and optimized, and the subsequent analytical performance evaluation and real sample analysis were performed by the extraction of six target analytes in sample solution containing 30% NaCl (pH 12.5) for 20 min with extraction temperature of 30 degrees C and stirring rate of 1000 rpm. Under such optimal conditions, the limits of detection (LODs, S/N=3) for the six target analytes were ranged from 8 microg/L (AP, KT) to 82 microg/L (MDA), with the enrichment factors (EFs) of 5-227 folds, and the relative standard deviations (RSDs, n=7) were in the range of 6.9-14.1%. The correlation coefficients of the calibration for the six target analytes over the dynamic linear range were higher than 0.9958. The application feasibility of HF-LPME-GC-FID in illegal drug monitoring was demonstrated by analyzing drug abuser urine samples, and the recoveries of target drugs for the spiked sample ranging from 75.2% to 119.3% indicated an excellent anti-interference capability of the developed method. The proposed method is simple, effective, sensitive and low-cost, and provides a much more accurate and sensitive detection platform over the conventional analytical techniques (such as immunological assay) for drug abuse analysis.

  5. Simultaneous determination of harpagoside and cinnamic acid in rat plasma by liquid chromatography electrospray ionization mass spectrometry and its application to pharmacokinetic studies.

    Science.gov (United States)

    Wang, Su-Jun; Ruan, Jin-Xiu; Zhao, Yan-Hong; Zhang, Zhen-Qing

    2008-01-01

    A simple and sensitive method was developed for the simultaneous quantification of harpagoside and cinnamic acid in rat plasma using high-performance liquid chromatography system coupled to a negative ion electrospray mass spectrometric analysis. The plasma sample preparation was a simple deproteinization by the addition of two volumes of acetonitrile. The analytes were separated on an Intersil C8-3 column (2.1 mm i.d.x250 mm, 5 microm) with acetonitrile-5 mm ammonium formate aqueous solution (60:40, v/v) as mobile phase at a flow-rate of 0.2 mL/min. Detection was performed on a quadrupole mass spectrometer equipped with electrospray ionization (ESI) source operated under selected ion monitoring (SIM) mode. [M+HCOO]- at m/z 539 for harpagoside, [M-H]- at m/z 147 for cinnamic acid and [M-H]- at m/z 137 for salylic acid (internal standard) were selected as detecting ions, respectively. The method was validated over the concentration range 7-250 ng/mL for harpagoside and 5-500 ng/mL for cinnamic acid. The lower limits of quantitation for harpagoside and cinnamic acid were 7 and 5 ng/mL, respectively. The intra- and inter-day precisions (RSD%) were within 9.5% and the assay accuracies (RE%) ranged from -5.3 to 3.0% for both analytes. Their average recoveries were greater than 86%. Both analytes were proved to be stable during all sample storage, preparation and analysis procedures. The method was successfully applied to the pharmacokinetic study of harpagoside and cinnamic acid following oral administration of Radix Scrophulariae extract to rats.

  6. [Simultaneous determination of eight additives in polymer food packaging materials by ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Xulong; Liu, Yin; Gong, Zhiguo; Wang, Pengju; Wang, Jide; Feng, Shun

    2014-08-01

    An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was proposed for the simultaneous determination of eight additives (Irgafos 168 (tri(2.4-di-tert-butylphenyl)phosphite), Irganox 1076 (octadecyl-β-(4-hydroxy-3, 5-di-tert-butylphenyl)propionate), Irganox 1010 (pentaerythritol tetrakys 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), BHA (butyl hydroxy anisole), TBHQ (tertiary butylhydroquinone), PG (propyl gallate), DG (dodecyl gallate), UV-326 (2-( 2'-hydroxyl-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole) in food packaging materials. After extracted by chloromethane through ultrasonic extraction, the samples were analyzed by UPLC-MS/MS. The chromatographic conditions were optimized, and the best separation was obtained on a Waters BEH-C18 column (50 mm x 2. 1 mm, 1.7 μm) with gradient elution of 0. 05% acetic acid solu- tion and methanol. The analysis was performed by UPLC-MS/MS with electrospray ionization (ESI) source in switching between the positive and negative ion modes in one run for multiple reaction monitoring. The eight additives showed good linear relationships in the ranges with all the correlation coefficients (R2) more than 0. 993. The limits of detection (LODs, S/N= 3) and limits of quantitation (LOQs, S/N= 10) of this method were 0. 13-5.50 μg/L and 0.45-17.50 μg/L, respectively. The recoveries were in the range of 63. 9% - 127. 0% with all the RSDs food packaging materials.

  7. A strategy for characterization of triterpene saponins in Caulophyllum robustum hairy roots by liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Xia, Yong-Gang; Li, Guo-Yu; Liang, Jun; Ortori, Catharine A; Yang, Bing-You; Kuang, Hai-Xue; Barrett, David A

    2014-11-01

    Triterpene saponins are important bioactive constituents widely distributed in many plants. Saponins present in Caulophyllum (Berberidaceae) have not been fully characterized. In this study, we studied triterpene saponins from Caulophyllum robustum using liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-qTOF-MS). Rapid identification of Caulophyllum saponins was facilitated using low and high MS cone voltages to induce controlled fragmentation in positive mode. The full scan spectra at low cone voltage of 40V provided considerable structural information relating to aglycone skeletons, sugar types, and linked sequences for Caulophyllum saponins. Seven Caulophyllum aglycones were differentiated and identified by their diagnostic fragment ions combined with accurate mass measurements and characteristic fragmentation pathways. Peak intensity ratio of [aglycone+H-2H2O](+) to [aglycone+H-H2O](+) in full scan spectra acquired with low cone voltage is correlated with structural features of hederagenin and echinocystic acid and is useful for the discrimination of these positional isomers. However, at a high voltage of 200V, the saponin [M+H](+) ion and its fragmentation ions were not present; and the single saponin