WorldWideScience

Sample records for combining time-of-flight spectroscopy

  1. A high-efficiency spin-resolved photoemission spectrometer combining time-of-flight spectroscopy with exchange-scattering polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jozwiak, Chris M.; Graff, Jeff; Lebedev, Gennadi; Andresen, Nord; Schmid, Andreas; Fedorov, Alexei; El Gabaly, Farid; Wan, Weishi; Lanzara, Alessandra; Hussain, Zahid

    2010-04-13

    We describe a spin-resolved electron spectrometer capable of uniquely efficient and high energy resolution measurements. Spin analysis is obtained through polarimetry based on low-energy exchange scattering from a ferromagnetic thin-film target. This approach can achieve a similar analyzing power (Sherman function) as state-of-the-art Mott scattering polarimeters, but with as much as 100 times improved efficiency due to increased reflectivity. Performance is further enhanced by integrating the polarimeter into a time-of-flight (TOF) based energy analysis scheme with a precise and flexible electrostatic lens system. The parallel acquisition of a range of electron kinetic energies afforded by the TOF approach results in an order of magnitude (or more) increase in efficiency compared to hemispherical analyzers. The lens system additionally features a 90 degrees bandpass filter, which by removing unwanted parts of the photoelectron distribution allows the TOF technique to be performed at low electron drift energy and high energy resolution within a wide range of experimental parameters. The spectrometer is ideally suited for high-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES), and initial results are shown. The TOF approach makes the spectrometer especially ideal for time-resolved spin-ARPES experiments.

  2. Magnetic excitations studied with time-of-flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rainford, B. [Southampton Univ. (United Kingdom). Dept. of Physics

    1996-11-01

    An introduction to time-of-flight neutron spectroscopy is presented in the context of the study of magnetic materials. Examples are taken from the class of rare earth and actinide magnetic materials known as `strongly correlated electron` systems. (author) 11 figs., 24 refs.

  3. Physical design of positronium time of flight spectroscopy apparatus

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiao-Pan; ZHANG Zi-Liang; QIN Xiu-Bo; YU Run-Sheng; WANG Bao-Yi

    2010-01-01

    Positronium time of flight spectroscopy(Ps-TOF)is an effective technique for porous material research.It has advantages over other techniques for analyzing the porosity and pore tortuosity of materials.This paper describes a design for Ps-TOF apparatus based on the Beijing intense slow positron beam,supplying a new material characterization technique.In order to improve the time resolution and increase the count rate of the apparatus,the detector system is optimized.For 3 eV o-Ps,the time broadening is 7.66 ns and the count rate is 3 cps after correction.

  4. Applying of the optical time-of-flight spectroscopy for the paper and pulp characterization

    Science.gov (United States)

    Pluciński, Jerzy

    2006-02-01

    The paper presents benefits of optical time-of-flight spectroscopy for the pulp and paper characterization. A semiconductor pulse laser and a streak camera as the photodetector were utilized in experimental part of research described in this paper. Distribution of the time of flight of photons through various kinds of wood pulp (e.g. pulp after mechanical treatment coming both fi-om tree species giving hard and soft wood and pulp after thermo-mechanical treatment) was measured. The pulp samples used in the measurements had consistency ranging from 0 to 5% of dry mass in the suspension. The influence of additives (kaolin, talc and calcium carbonate) present in the suspension on the time of flight distribution of photons was studied as well. Finally, dependence of the time of flight of photons through various kinds of the paper (i.e. newspaper, copy paper, and tissue) on the thickness of the sample was investigated.

  5. Advancements in time-resolved x-ray laser induced time-of-flight photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A J; Dunn, J; Widmann, K; Ao, T; Ping, Y; Hunter, J; Ng, A

    2005-07-28

    Time-resolved soft x-ray photoelectron spectroscopy is used to probe the non-steady-state evolution of the valence band electronic structure of laser heated ultra-thin (50 nm) metal foils and bulk semiconductors. Single-shot soft x-ray laser induced time-of-flight photoelectron spectroscopy with picosecond time resolution was used in combination with optical measurements of the disassembly dynamics that have shown the existence of a metastable liquid phase in fs-laser heated metal foils persisting 4-5 ps. This metastable phase is studied using a 527 nm wavelength 400 fs laser pulse containing 0.3-2.5 mJ laser energy focused in a large 500 x 700 {micro}m{sup 2} spot to create heated conditions of 0.2-1.8 x 10{sup 12} W cm{sup -2} intensity. The unique LLNL COMET compact tabletop soft x-ray laser source provided the necessary high photon flux, highly monoenergetic, picosecond pulse duration, and coherence for observing the evolution of changes in the valence band electronic structure of laser heated metals and semiconductors with picosecond time resolution. This work demonstrates the continuing development of a powerful new technique for probing reaction dynamics and changes of local order on surfaces on their fundamental timescales including phenomena such as non-thermal melting, chemical bond formation, intermediate reaction steps, and the existence of transient reaction products.

  6. Timing and Spectroscopy Requirements for a Plastic Scintillating Fiber Bundle Time-of-Flight Neutron Spectrometer

    Science.gov (United States)

    2013-12-01

    flexibility, efficiency, timing, and position resolution in developing novel Compton camera detectors capable of detecting special nuclear material. 1.3...oscilloscope needs to be fast enough to resolve coincident pulse events on the picoseconds to nanosecond time scale. The final objective is to experimentally...Mirsaleh-Kohan, W. D. Nasrin, and R. N. Compton , “Electron ionization time-of-flight mass spectroscopy: Historical review and current applications

  7. Non-destructive automatic leaf area measurements by combining stereo and time-of-flight images

    NARCIS (Netherlands)

    Song, Y.; Glasbey, C.A.; Polder, G.; Heijden, van der G.W.A.M.

    2014-01-01

    Leaf area measurements are commonly obtained by destructive and laborious practice. This study shows how stereo and time-of-flight (ToF) images can be combined for non-destructive automatic leaf area measurements. The authors focus on some challenging plant images captured in a greenhouse environmen

  8. Computationally effective solution of the inverse problem in time-of-flight spectroscopy

    DEFF Research Database (Denmark)

    Kamran, Faisal; Abildgaard, Otto Højager Attermann; Subash, Arman Ahamed

    2015-01-01

    Photon time-of-flight (PTOF) spectroscopy enables the estimation of absorption and reduced scattering coefficients of turbid media by measuring the propagation time of short light pulses through turbid medium. The present investigation provides a comparison of the assessed absorption and reduced...... scattering coefficients from PTOF measurements of intralipid 20% and India ink-based optical phantoms covering a wide range of optical properties relevant for biological tissues and dairy products. Three different models are used to obtain the optical properties by fitting to measured temporal profiles...

  9. Computationally effective solution of the inverse problem in time-of-flight spectroscopy

    DEFF Research Database (Denmark)

    Kamran, Faisal; Abildgaard, Otto Højager Attermann; Subash, Arman Ahamed;

    2015-01-01

    Photon time-of-flight (PTOF) spectroscopy enables the estimation of absorption and reduced scattering coefficients of turbid media by measuring the propagation time of short light pulses through turbid medium. The present investigation provides a comparison of the assessed absorption and reduced...... scattering coefficients from PTOF measurements of intralipid 20% and India ink-based optical phantoms covering a wide range of optical properties relevant for biological tissues and dairy products. Three different models are used to obtain the optical properties by fitting to measured temporal profiles...

  10. Spectral characterisation of dairy products using photon time-of-flight spectroscopy

    DEFF Research Database (Denmark)

    Nielsen, Otto Højager Attermann; Subash, Arman Ahamed; Nielsen, Frederik Donbæk

    2013-01-01

    In this paper, we present, for the first time, the absorption and reduced scattering spectra of commercially available milk and yoghurt products, obtained using photon-time-of-flight spectroscopy. The ability of this technique to separate the contributions from absorption and scattering in the sa......In this paper, we present, for the first time, the absorption and reduced scattering spectra of commercially available milk and yoghurt products, obtained using photon-time-of-flight spectroscopy. The ability of this technique to separate the contributions from absorption and scattering......) for milk with 0.1% fat in the near infrared range, to 60 cm(-1) for yoghurt with 3.0% fat in the green wavelength regime. The absorption is within the range of 0.05-0.5cm(-1), with only small variation in the absolute value between products. Our results show that the reduced scattering clearly...... distinguishes milk and yoghurt with the same fat content and can offer a reliable way of monitoring structural formation during milk fermentation....

  11. Estimation of optical parameters of highly scattering materials by time-of-flight spectroscopy

    Science.gov (United States)

    Plucinski, Jerzy

    2004-07-01

    Optical measurement methods are indispensable tool in biomedical research, providing invaluable information on optical properties of biological tissues. However, the application of these techniques is a big challenge, as most tissues are highly scattering materials whose optical properties cannot be measured in a straightforward way, due to multiple scattering of photons. Therefore, new optical measurement techniques and methods for highly scattering media are being developed to address this problem. One of the very promising techniques is time-of-flight spectroscopy. The paper presents problems encountered in reconstruction of basic optical parameters of tissues or other highly scattering materials from optical time-of-flight spectroscopy measurement data. To estimate the reconstruction accuracy of optical parameters (i.e. absorption coefficient, scattering coefficient, anisotropy factor and refractive index) the test data were generated by a computer program simulating light propagation in highly scattering material by Monte Carlo method. Following, a set of computer programs based on diffusion equation and optimization algorithms such as simplex method and genetic method were used to reconstruct optical parameters from the test data. Finally, by comparing reconstructed optical parameters with those used for generation of the test data, the accuracy of reconstructing algorithms it was estimated.

  12. Implications for Extraterrestrial Hydrocarbon Chemistry: Analysis of Ethylene (C2H4) and D4-Ethylene (C2D4) Ices Exposed to Ionizing Radiation via Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry

    Science.gov (United States)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2017-02-01

    The processing of the hydrocarbon ice, ethylene (C2H4/C2D4), via energetic electrons, thus simulating the processes in the track of galactic cosmic-ray particles, was carried out in an ultrahigh vacuum apparatus. The chemical evolution of the ices was monitored online and in situ utilizing Fourier transform infrared spectroscopy (FTIR) and during temperature programmed desorption, via a quadrupole mass spectrometer utilizing electron impact ionization (EI-QMS) and a reflectron time-of-flight mass spectrometer utilizing a photoionization source (PI-ReTOF-MS). Several previous in situ studies of ethylene ice irradiation using FTIR were substantiated with the detection of six products: [CH4 (CD4)], acetylene [C2H2 (C2D2)], the ethyl radical [C2H5 (C2D5)], ethane [C2H6 (C2D6)], 1-butene [C4H8 (C4D8)], and n-butane [C4H10 (C4D10)]. Contrary to previous gas phase studies, the PI-ReTOF-MS detected several groups of hydrocarbon with varying degrees of saturation: C n H2n+2 (n = 4–10), C n H2n (n = 2–12, 14, 16), C n H2n‑2 (n = 3–12, 14, 16), C n H2n‑4 (n = 4–12, 14, 16), C n H2n‑6 (n = 4–10, 12), C n H2n‑8 (n = 6–10), and C n H2n‑10 (n = 6–10). Multiple laboratory studies have shown the facile production of ethylene from methane, which is a known ice constituent in the interstellar medium. Various astrophysically interesting molecules can be associated with the groups detected here, such as allene/methylacetylene (C3H4) or 1, 3-butadiene (C4H6) and its isomers, which have been shown to lead to polycyclic aromatic hydrocarbons. Finally, several hydrocarbon groups detected here are unique to ethylene ice versus ethane ice and may provide understanding of how complex hydrocarbons form in astrophysical environments.

  13. Campaign 1.7 Pu Aging. Development of Time of Flight Secondary Ion Mass Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Venhaus, Thomas J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-09

    The first application of Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) to an aged plutonium surface has resulted in a rich set of surface chemistry data, as well as some unexpected results. FY15 was highlighted by not only the first mapping of hydrogen-containing features within the metal, but also a prove-in series of experiments using the system’s Sieverts Reaction Cell. These experiments involved successfully heating the sample to ~450 oC for nearly 24 hours while the sample was dosed several times with hydrogen, followed by an in situ ToF-SIMS analysis. During this year, the data allowed for better and more consistent identification of the myriad peaks that result from the SIMS sputter process. In collaboration with the AWE (U.K), the system was also fully aligned for sputter depth profiling for future experiments.

  14. Detection of renal cell carcinoma using neutron time of flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Rodrigo S.; Yoriyaz, Helio, E-mail: rodrigossviana@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Lakshmanan, Manu N.; Agasthya, Greeshma A.; Kapadia, Anuj J. [Duke University Medical Center, Durham, NC, (United States). Ravin Advanced Imaging Labs, Radiology

    2013-07-01

    The diagnosis of renal cell carcinoma (RCC) is challenging because the symptoms accompanying it are not unique to the disease, and can therefore be misdiagnosed as other diseases. Due to this characteristic, detection of renal cancer is incidental most of time, occurring via abdominal radiographic examinations unrelated to the disease. Presently, biopsy, which is invasive and an unpleasant procedure for the patient, is the most commonly used technique to diagnose RCC. In this study, we demonstrate the application of a novel noninvasive technique for detecting and imaging RCC in vivo. The elemental composition of biological tissues including kidneys has been investigated using a new technique called Neutron Stimulated Emission Computed Tomography (NSECT). This technique is based on detecting the energy signature emitted by the stable isotopes of elements in the body, which are stimulated to emit gamma radiation via inelastic neutron scattering. Methods for improving detection sensitivity and reducing dose, such as time-of-flight neutron spectroscopy have been explored. MCNP5 simulations were used to model the NSECT scanning of the human kidney where the energy and time of arrival of gamma photons were recorded in an ideal detector placed around the human torso. A 5 MeV collimated neutron beam was used to irradiate the kidney containing an RCC lesion. The resulting spectra were resolved in 100 picosecond and 1 keV time and energy bins, respectively. The preliminary results demonstrate the ability to localize the lesion through neutron time of flight spectroscopy and generate a tomographic image at a low dose to the patient. (author)

  15. Evaluation of the ID220 single photon avalanche diode for extended spectral range of photon time-of-flight spectroscopy

    DEFF Research Database (Denmark)

    Nielsen, Otto Højager Attermann; Dahl, Anders Bjorholm; Anderson-Engels, Stefan

    This paper describe the performance of the ID220 single photon avalanche diode for single photon counting, and investigates its performance for photon time-of-flight (PToF) spectroscopy. At first this report will serve as a summary to the group for PToF spectroscopy at the Department of Physics...

  16. Combined distance-of-flight and time-of-flight mass spectrometer

    Science.gov (United States)

    Enke, Christie G; Ray, Steven J; Graham, Alexander W; Hieftje, Gary M; Barinaga, Charles J; Koppenaal, David W

    2014-02-11

    A combined distance-of-flight mass spectrometry (DOFMS) and time-of-flight mass spectrometry (TOFMS) instrument includes an ion source configured to produce ions having varying mass-to-charge ratios, a first detector configured to determine when each of the ions travels a predetermined distance, a second detector configured to determine how far each of the ions travels in a predetermined time, and a detector extraction region operable to direct portions of the ions either to the first detector or to the second detector.

  17. Time-of-flight electron energy loss spectroscopy using TM110 deflection cavities

    Directory of Open Access Journals (Sweden)

    W. Verhoeven

    2016-09-01

    Full Text Available We demonstrate the use of two TM110 resonant cavities to generate ultrashort electron pulses and subsequently measure electron energy losses in a time-of-flight type of setup. The method utilizes two synchronized microwave cavities separated by a drift space of 1.45 m. The setup has an energy resolution of 12 ± 2 eV FWHM at 30 keV, with an upper limit for the temporal resolution of 2.7 ± 0.4 ps. Both the time and energy resolution are currently limited by the brightness of the tungsten filament electron gun used. Through simulations, it is shown that an energy resolution of 0.95 eV and a temporal resolution of 110 fs can be achieved using an electron gun with a higher brightness. With this, a new method is provided for time-resolved electron spectroscopy without the need for elaborate laser setups or expensive magnetic spectrometers.

  18. Time-of-flight electron energy loss spectroscopy using TM110 deflection cavities.

    Science.gov (United States)

    Verhoeven, W; van Rens, J F M; van Ninhuijs, M A W; Toonen, W F; Kieft, E R; Mutsaers, P H A; Luiten, O J

    2016-09-01

    We demonstrate the use of two TM110 resonant cavities to generate ultrashort electron pulses and subsequently measure electron energy losses in a time-of-flight type of setup. The method utilizes two synchronized microwave cavities separated by a drift space of 1.45 m. The setup has an energy resolution of 12 ± 2 eV FWHM at 30 keV, with an upper limit for the temporal resolution of 2.7 ± 0.4 ps. Both the time and energy resolution are currently limited by the brightness of the tungsten filament electron gun used. Through simulations, it is shown that an energy resolution of 0.95 eV and a temporal resolution of 110 fs can be achieved using an electron gun with a higher brightness. With this, a new method is provided for time-resolved electron spectroscopy without the need for elaborate laser setups or expensive magnetic spectrometers.

  19. Neutron time-of-flight spectroscopy measurement using a waveform digitizer

    Science.gov (United States)

    Liu, Long-Xiang; Wang, Hong-Wei; Ma, Yu-Gang; Cao, Xi-Guang; Cai, Xiang-Zhou; Chen, Jin-Gen; Zhang, Gui-Lin; Han, Jian-Long; Zhang, Guo-Qiang; Hu, Ji-Feng; Wang, Xiao-He

    2016-05-01

    The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the Thorium Molten Salt Reactor (TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal used for TOF calculation, with information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and γ-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The DAQ system developed is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy. Supported by Strategic Priority Research Program of the Chinese Academy of Science(TMSR) (XDA02010100), National Natural Science Foundation of China(NSFC)(11475245,No.11305239), Shanghai Key Laboratory of Particle Physics and Cosmology (11DZ2260700)

  20. Time-of-flight electron energy loss spectroscopy using TM110 deflection cavities

    Science.gov (United States)

    Verhoeven, W.; van Rens, J. F. M.; van Ninhuijs, M. A. W.; Toonen, W. F.; Kieft, E. R.; Mutsaers, P. H. A.; Luiten, O. J.

    2016-01-01

    We demonstrate the use of two TM110 resonant cavities to generate ultrashort electron pulses and subsequently measure electron energy losses in a time-of-flight type of setup. The method utilizes two synchronized microwave cavities separated by a drift space of 1.45 m. The setup has an energy resolution of 12 ± 2 eV FWHM at 30 keV, with an upper limit for the temporal resolution of 2.7 ± 0.4 ps. Both the time and energy resolution are currently limited by the brightness of the tungsten filament electron gun used. Through simulations, it is shown that an energy resolution of 0.95 eV and a temporal resolution of 110 fs can be achieved using an electron gun with a higher brightness. With this, a new method is provided for time-resolved electron spectroscopy without the need for elaborate laser setups or expensive magnetic spectrometers. PMID:27704035

  1. Broadband photon time of flight spectroscopy: advanced spectroscopic analysis for ensuring safety and performance of pharmaceutical tablets

    DEFF Research Database (Denmark)

    Kamran, Faisal; Nielsen, Otto Højager Attermann; Andersson-Engels, Stefan;

    2013-01-01

    We report on extended spectroscopic analysis of pharmaceutical tablets performed with broadband photon time-of-flight absorption/scaring spectroscopy. Precise monitoring of absorption and scattering spectra enables cost-efficient monitoring of key safety and performance parameters of the drugs....

  2. A collinear tandem time-of-flight mass spectrometer for infrared photodissociation spectroscopy of mass-selected ions

    Institute of Scientific and Technical Information of China (English)

    WANG GuanJun; CHI ChaoXian; XING XiaoPeng; DING ChuanFan; ZHOU MingFei

    2014-01-01

    An apparatus based on collinear tandem time-of-flight mass spectrometer has been designed for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase.The ions from a pulsed laser vaporization supersonic ion source are skimmed and mass separated by a Wiley-McLaren time-of-flight mass spectrometer.The ion of interest is mass selected,decelerated and dissociated by a tunable IR laser.The fragment and parent ions are reaccelerated and mass analyzed by the second time-of-flight mass spectrometer.A simple new assembly integrated with mass gate,deceleration and reacceleration ion optics was designed,which allows us to measure the infrared spectra of mass selected ions with high sensitivity and easy timing synchronization.

  3. Transmission Near-Infrared (NIR) and Photon Time-of-Flight (PTOF) Spectroscopy in a Comparative Analysis of Pharmaceuticals

    DEFF Research Database (Denmark)

    Kamran, Faisal; Abildgaard, Otto Højager Attermann; Sparén, Anders

    2015-01-01

    We present a comprehensive study of the application of photon time-of-flight spectroscopy (PTOFS) in the wavelength range 1050– 1350 nm as a spectroscopic technique for the evaluation of the chemical composition and structural properties of pharmaceutical tablets. PTOFS is compared to transmissio...... quantities such as scattering strength and slope of particle size. The ability of PTOFS to quantify the reduced scattering spectra, together with its robustness in predicting drug content, makes it suitable for such evaluations in the pharmaceutical industry.......We present a comprehensive study of the application of photon time-of-flight spectroscopy (PTOFS) in the wavelength range 1050– 1350 nm as a spectroscopic technique for the evaluation of the chemical composition and structural properties of pharmaceutical tablets. PTOFS is compared to transmission...

  4. Combining endoscopic ultrasound with Time-Of-Flight PET: The EndoTOFPET-US Project

    CERN Document Server

    Frisch, Benjamin

    2013-01-01

    The EndoTOFPET-US collaboration develops a multimodal imaging technique for endoscopic exams of the pancreas or the prostate. It combines the benefits of high resolution metabolic imaging with Time-Of-Flight Positron Emission Tomography (TOF PET) and anatomical imaging with ultrasound (US). EndoTOFPET-US consists of a PET head extension for a commercial US endoscope and a PET plate outside the body in coincidence with the head. The high level of miniaturization and integration creates challenges in fields such as scintillating crystals, ultra-fast photo-detection, highly integrated electronics, system integration and image reconstruction. Amongst the developments, fast scintillators as well as fast and compact digital SiPMs with single SPAD readout are used to obtain the best coincidence time resolution (CTR). Highly integrated ASICs and DAQ electronics contribute to the timing performances of EndoTOFPET. In view of the targeted resolution of around 1 mm in the reconstructed image, we present a prototype dete...

  5. Time-of-flight spectroscopy of muonic hydrogen atoms and molecules

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, M.C. [Dept. of Physics and Astronomy, Univ. of British Columbia, Vancouver, BC (Canada)]|[Dept. of Physics, Faculty of Science, Univ. of Tokyo (Japan); Adamczak, A. [Inst. of Nuclear Physics, Krakow (Poland); Bailey, J.M. [Chester Technology, Chester (United Kingdom); Beer, G.A.; Mason, G.R. [Dept. of Physics and Astronomy, Univ. of Victoria, BC (Canada); Beveridge, J.L.; Marshall, G.M.; Olin, A. [TRIUMF, Vancouver, BC (Canada); Faifman, M.P. [Russian Research Center, Kurchatov Inst., Moscow (Russian Federation); Huber, T.M. [Dept. of Physics, Gustavus Adolphus Coll., St. Peter, MN (United States); Kammel, P. [Dept. of Physics and Lawrence Berkeley National Lab., Univ. of California, Berkeley, CA (United States); Kim, S.K. [Dept. of Physics, Jeonbuk National Univ., Jeonju City (Korea); Knowles, P.E.; Mulhauser, F. [Inst. of Physics, Univ. of Fribourg (Switzerland); Kunselman, A.R. [Dept. of Physics and Astronomy, Univ. of Wyoming, Laramie, WY (United States); Markushin, V.E.; Petitjean, C. [Paul Scherrer Inst., Villigen (Switzerland); Porcelli, T.A. [Dept. of Physics, Univ. of Northern British Columbia, Prince George, BC (Canada); Zmeskal, J. [Inst. for Medium Energy Physics, Austrian Academy of Sciences, Vienna (Austria)

    2001-07-01

    Studies of muonic hydrogen atoms and molecules have been performed traditionally in bulk targets of gas, liquid or solid. At TRIUMF, Canada's meson facility, we have developed a new type of target system using multilayer thin films of solid hydrogen, which provides a beam of muonic hydrogen atoms in vacuum. Using the time-of-flight of the muonic atoms, the energy-dependent information of muonic reactions are obtained in direct manner.We discuss some unique measurements enabled by the new technique, with emphasis on processes relevant to muon catalyzed fusion.

  6. Time-of-Flight Spectroscopy of Muonic Hydrogen Atoms and Molecules

    CERN Document Server

    Fujiwara, M C; Bailey, J M; Beer, G A; Beveridge, J L; Faifman, M P; Huber, T M; Kammel, P; Kim, S K; Knowles, P E; Kunselman, A R; Markushin, V E; Marshall, G M; Mason, G R; Mulhauser, F; Olin, A; Petitjean, C; Porcelli, T A; Zmeskal, J

    2001-01-01

    Studies of muonic hydrogen atoms and molecules have been performed traditionally in bulk targets of gas, liquid or solid. At TRIUMF, Canada's meson facility, we have developed a new type of target system using multilayer thin films of solid hydrogen, which provides a beam of muonic hydrogen atoms in vacuum. Using the time-of-flight of the muonic atoms, the energy-dependent information of muonic reactions are obtained in direct manner. We discuss some unique measurements enabled by the new technique, with emphasis on processes relevant to muon catalyzed fusion.

  7. Identification of heavy nuclei by combination of magnetic analysis time of flight and energy measurements

    CERN Document Server

    Stéphan, C; Garron, J P; Jacmart, J C; Poffé, N; Tassan-Got, L

    1976-01-01

    The addition of a time of flight measurement to a Delta E-E telescope set up in the focal plane of a magnetic spectrometer improves the identification of very heavy ions. The Delta E silicon detector is 8 mu thick. The time of flight is measured between a thin plastic scintillator at the entrance of the spectrometer and the Delta E detector, which gives a flight path of 3 m. In order to compensate for the different lengths of the trajectories, the plastic is bent at 15 degrees along the mean trajectory. In these conditions, one has obtained a time resolution of 0.7 ns with a solid angle of 1.8 10/sup -3/ sr (horizontal 2 degrees , vertical 3 degrees ). In these conditions, preliminary results already give an unambiguous identification up to mass approximately=100.

  8. Non-destructive Analysis of Material Detachments from Polychromatically Glazed Terracotta Artwork by THz Time-of-Flight Spectroscopy

    Science.gov (United States)

    Krügener, Kirsti; Busch, Stefan F.; Soltani, Amin; Castro-Camus, Enrique; Koch, Martin; Viöl, Wolfgang

    2017-04-01

    The damage caused by the environment to exposed glazed terracotta objects is usually not externally visible. For instance, the detachment of the glaze owing to subsurface crack formation or whole cavities in the area of the terracotta cannot be located visually. In this article, we demonstrate that terahertz time-of-flight spectroscopy is suitable to locate and measure the air gaps under the glaze detachments which could only be done by X-ray axial tomography before. This tool will be very useful to guide the restoration process, particularly for pieces that are still attached to buildings or other structures that cannot be transported to a tomography facility.

  9. Spherical neutron polarimetry applied to spin-echo and time-of-flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lelievre-Berna, E., E-mail: lelievre@ill.e [Institut Laue Langevin (ILL), 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Bentley, P.; Bourgeat-Lami, E.; Thomas, M. [Institut Laue Langevin (ILL), 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Pappas, C. [Helmholtz Centre Berlin for Materials and Energy (HCB), Glienickerstr. 100, 14109 Berlin (Germany); Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Kischnik, R.; Moskvin, E. [Helmholtz Centre Berlin for Materials and Energy (HCB), Glienickerstr. 100, 14109 Berlin (Germany)

    2009-09-01

    The changes in direction of the neutron spin that take place on scattering by a magnetic interaction vector are highly dependent on their relative directions. In some circumstances, without zero-field polarimeter, it is impossible to distinguish between a simple depolarisation and a rotation of the polarisation vector. Motivated by the investigation of chiral magnetic fluctuations, we have implemented the third-generation zero-field polarimeter Cryopad on the neutron spin-echo spectrometer SPAN at the Helmholtz Centre Berlin (HCB). We present the method and the limitations of this novel technique that is now available on IN15 at the ILL. The huge progress accomplished with {sup 3}He neutron spin filters/flippers are going to facilitate the exploitation of polarised beams at spallation sources. Zero-field polarimeters like Cryopad are used routinely at several steady-state sources but their design would be inefficient at a pulse source. We have investigated the possibility to implement a zero-field polarimeter on a time-of-flight spectrometer. We propose a design that would lead to a better efficiency and present the finite element calculations.

  10. Neutrino mass sensitivity by MAC-E-Filter based time-of-flight spectroscopy with the example of KATRIN

    CERN Document Server

    Steinbrink, Nicholas; Martin, Eric L; Robertson, R G Hamish; Zacher, Michael; Weinheimer, Christian

    2013-01-01

    The KATRIN experiment aims at a measurement of the neutrino mass with a 90 % C.L. sensitivity of 0.2 eV/c$^2$ by measuring the endpoint region of the tritium $\\beta$ decay spectrum from a windowless gaseous molecular tritium source using an integrating spectrometer of the MAC-E-Filter type. We discuss the idea of using the MAC-E-Filter in a time-of-flight mode (MAC-E-TOF) in which the neutrino mass is determined by a measurement of the electron time-of-flight (TOF) spectrum that depends on the neutrino mass. MAC-E-TOF spectroscopy here is a very sensitive method since the $\\beta$-electrons are slowed down to distinguishable velocities by the MAC-E-Filter. Their velocity depends strongly on their surplus energy above the electric retarding potential. Using MAC-E-TOF, a statistical sensitivity gain is expected. Because a small number of retarding-potential settings is sufficient for a complete measurement, in contrast to about 40 different retarding potentials used in the standard MAC-E-Filter mode, there is a ...

  11. A simple electron time-of-flight spectrometer for ultrafast vacuum ultraviolet photoelectron spectroscopy of liquid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Arrell, C. A., E-mail: christopher.arrell@epfl.ch; Ojeda, J.; Mourik, F. van; Chergui, M. [Laboratory of Ultrafast Spectroscopy, ISIC, Station 6, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Sabbar, M.; Gallmann, L.; Keller, U. [Physics Department, ETH Zurich, 8093 Zurich (Switzerland); Okell, W. A.; Witting, T.; Siegel, T.; Diveki, Z.; Hutchinson, S.; Tisch, J. W.G.; Marangos, J. P. [Department of Physics, The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom); Chapman, R. T.; Cacho, C.; Rodrigues, N.; Turcu, I. C.E.; Springate, E. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxon OX11 0QX (United Kingdom)

    2014-10-01

    We present a simple electron time of flight spectrometer for time resolved photoelectron spectroscopy of liquid samples using a vacuum ultraviolet (VUV) source produced by high-harmonic generation. The field free spectrometer coupled with the time-preserving monochromator for the VUV at the Artemis facility of the Rutherford Appleton Laboratory achieves an energy resolution of 0.65 eV at 40 eV with a sub 100 fs temporal resolution. A key feature of the design is a differentially pumped drift tube allowing a microliquid jet to be aligned and started at ambient atmosphere while preserving a pressure of 10⁻¹ mbar at the micro channel plate detector. The pumping requirements for photoelectron (PE) spectroscopy in vacuum are presented, while the instrument performance is demonstrated with PE spectra of salt solutions in water. The capability of the instrument for time resolved measurements is demonstrated by observing the ultrafast (50 fs) vibrational excitation of water leading to temporary proton transfer.

  12. Photocarrier transport dynamics in InAs/GaAs quantum dot superlattice solar cells using time-of-flight spectroscopy

    Science.gov (United States)

    Tanibuchi, T.; Kada, T.; Asahi, S.; Watanabe, D.; Kaizu, T.; Harada, Y.; Kita, T.

    2016-11-01

    We studied time-resolved photocarrier transport through InAs/GaAs quantum dot superlattice (QDSL) solar cells (SCs) using time-of-flight spectroscopy with an optical probe QD structure beneath the QDSL. Carriers optically pumped in the top p -GaAs layer were transported through the intrinsic layer, including the QDSLs, before arriving at the probe QDs. The photoexcited carrier density significantly influenced the time-resolved photoluminescence (PL) of the QDSLs and probe QDs. The time-resolved PL profile of the probe QDs indicated that excitation densities in excess of 25 nJ /c m2 drastically decreased the rise time, suggesting rapid carrier transport through the QDSLs. This was also confirmed by QDSL carrier transport dynamics, for which the PL intensity of the excited states decayed rapidly above this excitation power density, 25 nJ /c m2 , while the ground state remained constant. These results demonstrate that filling the ground states of QDSLs and starting to populate the excited state miniband accelerates carrier transport in QDSL SCs. Furthermore, according to two-step photon absorption measurements taken with a 1.3-μm infrared laser light source, electrons play a key role in the generation of extra photocurrent by sub-band-gap photon irradiation.

  13. Underwater Localization by combining Time-of-Flight and Direction-of-Arrival

    NARCIS (Netherlands)

    Kleunen, van Wouter A.P.; Blom, Koen C.H.; Meratnia, Nirvana; Kokkeler, André B.J.; Havinga, Paul J.M.; Smit, Gerard J.M.

    2014-01-01

    In this paper we present a combined ToF and DoA localization approach suitable for shallow underwater monitoring applications such as harbor monitoring. Our localization approach combines one-way ranging and DoA estimation to calculate both position and time-synchronization of the blind-node. We wil

  14. Dispersive liquid-liquid microextraction combined with capillary electrophoresis and time-of-flight mass spectrometry for urine analysis.

    Science.gov (United States)

    Kohler, Isabelle; Schappler, Julie; Sierro, Tatiana; Rudaz, Serge

    2013-01-25

    The combination of dispersive liquid-liquid microextraction (DLLME) with capillary electrophoresis (CE) and a time-of-flight mass spectrometer (TOF-MS) was evaluated for the toxicological screening in urine samples. A methodology based on design of experiments (DOE) was implemented to increase the extraction efficiency. Dichloromethane and isopropanol were selected as the extraction and dispersing solvents, respectively. Seven factors for DLLME were screened with the help of a Plackett-Burmann DOE using two model compounds before fine investigation of the important parameters to maximise the compound extraction. These experiments were performed in the CE-UV configuration to overcome potential MS matrix effects. The performance of the entire procedure was then evaluated using CE-ESI-TOF-MS. With a preconcentration factor of more than 130, the highly sensitive DLLME-CE-ESI-TOF-MS method allowed for the detection of 30 toxicological compounds (i.e., amphetamines and their derivatives, opiates, cocaine and its metabolites and pharmaceuticals) in urine with limits of detection in the sub-ng/mL level and was used to analyse real toxicological samples. The combination of DLLME and CE was particularly attractive because of the small amount of organic solvents required.

  15. A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis

    Science.gov (United States)

    Ström, Petter; Petersson, Per; Rubel, Marek; Possnert, Göran

    2016-10-01

    A dedicated detector system for heavy ion elastic recoil detection analysis at the Tandem Laboratory of Uppsala University is presented. Benefits of combining a time-of-flight measurement with a segmented anode gas ionization chamber are demonstrated. The capability of ion species identification is improved with the present system, compared to that obtained when using a single solid state silicon detector for the full ion energy signal. The system enables separation of light elements, up to Neon, based on atomic number while signals from heavy elements such as molybdenum and tungsten are separated based on mass, to a sample depth on the order of 1 μm. The performance of the system is discussed and a selection of material analysis applications is given. Plasma-facing materials from fusion experiments, in particular metal mirrors, are used as a main example for the discussion. Marker experiments using nitrogen-15 or oxygen-18 are specific cases for which the described improved species separation and sensitivity are required. Resilience to radiation damage and significantly improved energy resolution for heavy elements at low energies are additional benefits of the gas ionization chamber over a solid state detector based system.

  16. Molecular relaxation in supersonic free jets of N2 and CH4 from stimulated Raman spectroscopy and time-of-flight measurements

    OpenAIRE

    Abad, Laura; Bermejo, Dionisio; Herrero, Víctor J.; Santos, J.; Tanarro, Isabel

    1997-01-01

    The relaxation of the energy stored in the translational and rotational degrees of freedom of N2 and CH4 in the course of free jet expansions has been experimentally studied. Rotational temperatures along the expansion axis were obtained by means of stimulated Raman spectroscopy, and terminal flow velocities and translational temperatures were determined from supersonic beam time-of-flight measurements. From these measurements low-temperature cross sections for rotational relaxation have been...

  17. Complex Hydrocarbon Chemistry in Interstellar and Solar System Ices Revealed: A Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry Analysis of Ethane (C2H6) and D6-Ethane (C2D6) Ices Exposed to Ionizing Radiation

    Science.gov (United States)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-08-01

    The irradiation of pure ethane (C2H6/C2D6) ices at 5.5 K, under ultrahigh vacuum conditions was conducted to investigate the formation of complex hydrocarbons via interaction with energetic electrons simulating the secondary electrons produced in the track of galactic cosmic rays. The chemical modifications of the ices were monitored in situ using Fourier transform infrared spectroscopy (FTIR) and during temperature-programmed desorption via mass spectrometry exploiting a quadrupole mass spectrometer with electron impact ionization (EI-QMS) as well as a reflectron time-of-flight mass spectrometer coupled to a photoionization source (PI-ReTOF-MS). FTIR confirmed previous ethane studies by detecting six molecules: methane (CH4), acetylene (C2H2), ethylene (C2H4), the ethyl radical (C2H5), 1-butene (C4H8), and n-butane (C4H10). However, the TPD phase, along with EI-QMS, and most importantly, PI-ReTOF-MS, revealed the formation of at least 23 hydrocarbons, many for the first time in ethane ice, which can be arranged in four groups with an increasing carbon-to-hydrogen ratio: C n H2n+2 (n = 3, 4, 6, 8, 10), C n H2n (n = 3-10), {{{C}}}n{{{H}}}2n-2 (n = 3-10), and {{{C}}}n{{{H}}}2n-4 (n = 4-6). The processing of simple ethane ices is relevant to the hydrocarbon chemistry in the interstellar medium, as ethane has been shown to be a major product of methane, as well as in the outer solar system. These data reveal that the processing of ethane ices can synthesize several key hydrocarbons such as C3H4 and C4H6 isomers, which ha­ve been found to synthesize polycyclic aromatic hydrocarbons like indene (C9H8) and naphtha­lene (C10H8) in the ISM and in hydrocarbon-rich atmospheres of planets and their moons such as Titan.

  18. HORACE: software for the analysis of data from single crystal spectroscopy experiments at time-of-flight neutron instruments

    CERN Document Server

    Ewings, R A; Le, M D; van Duijn, J; Bustinduy, I; Perring, T G

    2016-01-01

    The HORACE suite of programs has been developed to work with large multiple-measurement data sets collected from time-of-flight neutron spectrometers equipped with arrays of position-sensitive detectors. The software allows exploratory studies of the four dimensions of reciprocal space and excitation energy to be undertaken, enabling multi-dimensional subsets to be visualized, algebraically manipulated, and models for the scattering to simulated or fitted to the data. The software is designed to be an extensible framework, thus allowing user-customized operations to be performed on the data. Examples of the use of its features are given for measurements exploring the spin waves of the simple antiferromagnet RbMnF$_{3}$ and ferromagnetic iron, and the phonons in URu$_{2}$Si$_{2}$.

  19. HORACE: Software for the analysis of data from single crystal spectroscopy experiments at time-of-flight neutron instruments

    Science.gov (United States)

    Ewings, R. A.; Buts, A.; Le, M. D.; van Duijn, J.; Bustinduy, I.; Perring, T. G.

    2016-10-01

    The HORACE suite of programs has been developed to work with large multiple-measurement data sets collected from time-of-flight neutron spectrometers equipped with arrays of position-sensitive detectors. The software allows exploratory studies of the four dimensions of reciprocal space and excitation energy to be undertaken, enabling multi-dimensional subsets to be visualized, algebraically manipulated, and models for the scattering to simulated or fitted to the data. The software is designed to be an extensible framework, thus allowing user-customized operations to be performed on the data. Examples of the use of its features are given for measurements exploring the spin waves of the simple antiferromagnet RbMnF3 and ferromagnetic iron, and the phonons in URu2Si2.

  20. Direct Mass Measurements in the Light Neutron-Rich Region Using a Combined Energy and Time-of-Flight Technique

    Science.gov (United States)

    Pillai, C.; Swenson, L. W.; Vieira, D. J.; Butler, G. W.; Wouters, J. M.; Rokni, S. H.; Vaziri, K.; Remsberg, L. P.

    This experiment has demonstrated that direct mass measurements can be performed (albeit of low precision in this first attempt) using the M proportional to ET(2) method. This technique has the advantage that many particle-bound nuclei, produced in fragmentation reactions can be measured simultaneously, independent of their N or Z. The main disadvantage of this approach is that both energy and time-of-flight must be measured precisely on an absolute scale. Although some mass walk with N and Z was observed in this experiment, these uncertainties were largely removed by extrapolating the smooth dependence observed for known nuclei which lie closer to the valley of (BETA)-stability. Mass measurements for several neutron-rich light nuclei ranging from C-17 to NE-26 have been performed. In all cases these measurements agree with the latest mass compilation of Wapstra and Audi. The masses of N-20 N and F-24 have been determined for the first time.

  1. High resolution pulsed field ionization photoelectron spectroscopy using multibunch synchrotron radiation: Time-of-flight selection scheme

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, G.K. [Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Song, Y.; Ng, C.Y. [Ames Laboratory, United States Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)

    1999-06-01

    We have developed an efficient electron time-of-flight (TOF) selection scheme for high resolution pulsed field ionization (PFI) photoelectron (PFI-PE) measurements using monochromatized multibunch undulator synchrotron radiation at the Advanced Light Source. By employing a simple electron TOF spectrometer, we show that PFI-PEs produced by the PFI in the dark gap of a synchrotron ring period can be cleanly separated from prompt background photoelectrons. A near complete suppression of prompt electrons was achieved in PFI-PE measurements by gating the PFI-PE TOF peak, as indicated by monitoring background electron counts at the Ar(11s{sup {prime}}) autoionizing Rydberg peak, which is adjacent to the Ar{sup +}({sup 2}P{sub 3/2}) PFI-PE band. The rotational-resolved PFI-PE band for H{sub 2}{sup +} (X {sup 2}{Sigma}{sub g}{sup +},v{sup +}=0) measured using this electron TOF selection scheme is nearly free from residues of nearby autoionizing features, which were observed in the previous measurement by employing an electron spectrometer equipped with a hemispherical energy analyzer. This comparison indicates that the TOF PFI-PE scheme is significantly more effective in suppressing the hot-electron background. In addition to attaining a high PFI-PE transmission, a major advantage of the electron TOF scheme is that it allows the use of a smaller pulsed electric field and thus results in a higher instrumental PFI-PE resolution. We have demonstrated instrumental resolutions of 1.0 cm{sup {minus}1} full width at half maximum (FWHM) and 1.9 cm{sup {minus}1} FWHM in the PFI-PE bands for Xe{sup +}({sup 2}P{sub 3/2}) and Ar{sup +}({sup 2}P{sub 3/2}) at 12.123 and 15.760 eV, respectively. These resolutions are more than a factor 2 better than those achieved in previous synchrotron based PFI-PE studies. {copyright} {ital 1999 American Institute of Physics.}

  2. Photoabsorption and time-of-flight mass spectroscopy for gas-phase trimethyl phosphate following valence shell excitation

    Energy Technology Data Exchange (ETDEWEB)

    Homem, M.G.P.; Rosa, L.F.S.; Farenzena, L.S.; Hasse, A. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil); Iza, P. [Escuela Superior Politecnica del Litoral, Guayaquil Guaya (Ecuador); Cavasso Filho, R.L. [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil); Lee, M.T.; Iga, I. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil)

    2012-07-01

    Full text: In this work we report an experimental study on photoabsorption of trimethyl phosphate (TMP) molecules in the vacuum-ultraviolet energy range. More specifically, absolute photoabsorption cross sections and photoionization yields are measured and reported in the (11.11-21.45) eV energy range. The photoionization and neutral-decay cross sections in absolute scale are also derived and reported. Details of our experimental setup and procedure for cross-section determination can be found in our previous work [1]. Essentially, the measurements were performed using a double-ion-chamber technique [2]. The experimental cross-section results are analyzed in comparison with PES measurements. Oscillator strengths sum rules over the extrapolated experimental data gives a value of 71.6 au for the static dipole polarizability of TMP, which is in excellent agreement with the value of 72.3 au reported in literature. In addition, the ionic dissociation in the same energy range has been studied by time-of-flight mass spectrometry [3]. The detected product cations are C{sub 3}H{sub 9}O{sub 4}P{sup +}, C{sub 3}H{sub 8}O{sub 4}P{sup +}, CH{sub 3}O{sub 4}P{sup +}, C{sub 2}H{sub 6}O{sub 3}P{sup +}, PO{sub 4}{sup +}, CH{sub 5}O{sub 2}P{sup +}, PO{sub 3}{sup +}, and CH{sub 3}{sup +}. The observed ionic branching ratios are converted in absolute scale by using the measured photoionization cross sections. The presence of two ionic metastable states corresponding to the C{sub 3}H{sub 9}O{sub 4}P{sup +} and CH{sub 3}O{sub 4}P{sup +} fragments are reported and their metastable ion mean lives are estimated in (152{+-}5) ns and (248{+-}30) ns. The results and discussion will be presented during the workshop. [1] M. G. P. Homem, P. Iza, L. S. Farenzena, R. L. Cavasso-Filho, M. T. Lee and I. Iga, J. Phys. B: At. Mol. Opt. Phys. 42, 235204 (2009). [2] J. A. R. Samson and Lifeng Yin, J. Opt. Soc. Am B 6, 2326 (1989). [3] F. Burmeister, L. H. Coutinho, R. R. T. Marinho, M. G. P. Homem, M. A

  3. Rapid 'de novo' peptide sequencing by a combination of nanoelectrospray, isotopic labeling and a quadrupole/time-of-flight mass spectrometer.

    Science.gov (United States)

    Shevchenko, A; Chernushevich, I; Ens, W; Standing, K G; Thomson, B; Wilm, M; Mann, M

    1997-01-01

    Protein microanalysis usually involves the sequencing of gel-separated proteins available in very small amounts. While mass spectrometry has become the method of choice for identifying proteins in databases, in almost all laboratories 'de novo' protein sequencing is still performed by Edman degradation. Here we show that a combination of the nanoelectrospray ion source, isotopic end labeling of peptides and a quadrupole/ time-of-flight instrument allows facile read-out of the sequences of tryptic peptides. Isotopic labeling was performed by enzymatic digestion of proteins in 1:1 16O/18O water, eliminating the need for peptide derivatization. A quadrupole/time-of-flight mass spectrometer was constructed from a triple quadrupole and an electrospray time-of-flight instrument. Tandem mass spectra of peptides were obtained with better than 50 ppm mass accuracy and resolution routinely in excess of 5000. Unique and error tolerant identification of yeast proteins as well as the sequencing of a novel protein illustrate the potential of the approach. The high data quality in tandem mass spectra and the additional information provided by the isotopic end labeling of peptides enabled automated interpretation of the spectra via simple software algorithms. The technique demonstrated here removes one of the last obstacles to routine and high throughput protein sequencing by mass spectrometry.

  4. Characterization of gate oxynitrides by means of time of flight secondary ion mass spectrometry and x-ray photoelectron spectroscopy. Quantification of nitrogen

    CERN Document Server

    Ferrari, S; Fanciulli, M

    2002-01-01

    We present a methodology for the quantitative estimation of nitrogen in ultrathin oxynitrides by means of time of flight secondary ion mass spectrometry (TOF-SIMS) and x-ray photoelectron spectroscopy (XPS). We consider an innovative approach to TOF-SIMS depth profiling, by elemental distribution of single species as sum of peaks containing such species. This approach is very efficient in overcoming matrix effect arising when quantifying elements were distributed in silicon and silicon oxide. We use XPS to calibrate TOF-SIMS and to obtain quantitative information on nitrogen distribution in oxynitride thin layers. In the method we propose we process TOF-SIMS and XPS data simultaneously to obtain a quantitative depth profile.

  5. Determination of true optical absorption and scattering coefficient of wooden cell wall substance by time-of-flight near infrared spectroscopy.

    Science.gov (United States)

    Kitamura, Ryunosuke; Inagaki, Tetsuya; Tsuchikawa, Satoru

    2016-02-22

    The true absorption coefficient (μa) and reduced scattering coefficient (μ´s) of the cell wall substance in Douglas fir were determined using time-of-flight near infrared spectroscopy. Samples were saturated with hexane, toluene or quinolone to minimize the multiple reflections of light on the boundary between pore-cell wall substance in wood. μ´s exhibited its minimum value when the wood was saturated with toluene because the refractive index of toluene is close to that of the wood cell wall substance. The optical parameters of the wood cell wall substance calculated were μa = 0.030 mm(-1) and μ´s= 18.4 mm(-1). Monte Carlo simulations using these values were in good agreement with the measured time-resolved transmittance profiles.

  6. Lu1-xI3:Cex--A Scintillator for gamma ray spectroscopy and time-of-flight PET

    Science.gov (United States)

    Shah, Kanai S.

    2009-03-17

    The present invention concerns very fast scintillator materials comprising lutetium iodide doped with Cerium Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration. The timing resolution of the scintillators of the present invention provide compositions capable of resolving the position of an annihilation event within a portion of a human body cross-section.

  7. Comparison of the Detection Characteristics of Trace Species Using Laser-Induced Breakdown Spectroscopy and Laser Breakdown Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Zhenzhen Wang

    2015-03-01

    Full Text Available The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS and laser breakdown time-of-flight mass spectrometry (LB-TOFMS. Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application.

  8. Comparison of the Detection Characteristics of Trace Species Using Laser-Induced Breakdown Spectroscopy and Laser Breakdown Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Wang, Zhenzhen; Deguchi, Yoshihiro; Yan, Junjie; Liu, Jiping

    2015-01-01

    The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS) and laser breakdown time-of-flight mass spectrometry (LB-TOFMS). Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application. PMID:25769051

  9. Comparison of the detection characteristics of trace species using laser-induced breakdown spectroscopy and laser breakdown time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Zhenzhen; Deguchi, Yoshihiro; Yan, Junjie; Liu, Jiping

    2015-03-11

    The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS) and laser breakdown time-of-flight mass spectrometry (LB-TOFMS). Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application.

  10. Identification of Natural Dyes in Ancient Textiles by Time-of-Flight Secondary Ion Mass Spectrometry and Surface-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Lee, Jihye; Kim, Min Jung; van Elslande, Elsa; Walter, Philippe; Lee, Yeonhee

    2015-11-01

    The identification of dyes in archaeological remains is a long standing challenge. Major problems include contamination by environmental conditions over long periods of time, small amounts and limited availability of excavated samples, and low concentrations of dyestuff in the obtained samples. To address these issues, highly sensitive and non-destructive techniques are required. In response, in this work, two non-destructive analytical techniques, Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Surface-Enhanced Raman Spectroscopy (SERS), were used for dye detection and the analysis results are compared. TOF-SIMS provides high detection efficiency for the analysis of organic materials whereas SERS is a useful technique for the detection of dyes in ancient textiles. An Ag colloid was employed to surmount the limitations of normal Raman measurement such as background fluorescence and weak Raman signals in small amounts of components. To identify the dyes used in ancient textiles, standard samples prepared using various dyestuffs and historical samples were analyzed with TOF-SIMS and Raman techniques. From the TOF-SIMS and the SERS spectra, dyestuffs such as alizarin, berberine, an indigo were identified in ancient textiles. The results suggest that TOF-SIMS and SERS are efficient non-destructive techniques for the characterization of archaeological textiles.

  11. Analytical strategy based on the combination of gas chromatography coupled to time-of-flight and hybrid quadrupole time-of-flight mass analyzers for non-target analysis in food packaging.

    Science.gov (United States)

    Cherta, L; Portolés, T; Pitarch, E; Beltran, J; López, F J; Calatayud, C; Company, B; Hernández, F

    2015-12-01

    The potential of an advanced analytical strategy based on the use of gas chromatography (GC) coupled to high resolution mass spectrometry (HRMS) with two different analyzers and ionization sources has been investigated and applied to the non-target analysis of food packaging contaminants. Initially, the approach based on GC-time-of-flight (TOF) MS with electron ionization (EI) source allowed performing a library search and mass accurate measurements of selected ions. Then, a second analysis was performed using hybrid quadrupole (Q) TOF MS with an atmospheric pressure chemical ionization (APCI) source in order to search for the molecular ion or the protonated molecule and study the fragmentation behavior. This analytical strategy was applied to the analysis of four polypropylene/ethylene vinyl alcohol/polypropylene (PP/EVOH/PP) multilayer trays and one PP/Al foil/PP film, each one subjected to migration assays with the food simulants isooctane and Tenax®, in order to investigate its potential on the determination of migrant substances.

  12. Screening and identification of various components in Thalictrum fortunei using a combination of liquid chromatography/time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Cheng, H X; Zeng, Y C; Jia, B Y; Fang, C F; Cheng, W M

    2012-02-01

    An approach for screening and identification of various components in a traditional Chinese medicine (TCM), using a combination of LC/TOF-MS technique was described in this paper. The chemical profile of Thalictrum fortunei, well-known in TCM, was studied using the established method. The possibilities of screening and identifying non-target components inside TCM with modern data acquisition methods of acceleration time of flight mass spectrometers, such as data-dependent MS to MS/MS switching were investigated. As a result, 27 components were identified. This study was aimed to screen and identify the main components of T. fortunei using LC/TOF-MS, expecting to provide a rapid, sensitive, economical and systematical method for the identification and further quality evaluation of TCM preparation.

  13. Elemental analysis of coal by tandem laser induced breakdown spectroscopy and laser ablation inductively coupled plasma time of flight mass spectrometry

    Science.gov (United States)

    Dong, Meirong; Oropeza, Dayana; Chirinos, José; González, Jhanis J.; Lu, Jidong; Mao, Xianglei; Russo, Richard E.

    2015-07-01

    The capabilities and analytical benefits of combined LIBS and LA-ICP-MS were evaluated for the analysis of coal samples. The ablation system consisted of a Nd:YAG laser operated 213 nm. A Czerny-turner spectrograph with ICCD detector and time-of-flight based mass spectrometer were utilized for LIBS and ICP-MS detection, respectively. This tandem approach allows simultaneous determination of major and minor elements (C, Si, Ca, Al, Mg), and trace elements (V, Ba, Pb, U, etc.) in the coal samples. The research focused on calibration strategies, specifically the use of univariate and multivariate data analysis on analytical performance. Partial least square regression (PLSR) was shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The correlation between measurements from these two techniques demonstrated that mass spectral data combined with LIBS emission measurements by PLSR improved the accuracy and precision for quantitative analysis of trace elements in coal.

  14. Elemental analysis of coal by tandem laser induced breakdown spectroscopy and laser ablation inductively coupled plasma time of flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Meirong [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Oropeza, Dayana [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Chirinos, José [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1041a (Venezuela, Bolivarian Republic of); González, Jhanis J. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Lu, Jidong [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Mao, Xianglei [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Russo, Richard E., E-mail: RERusso@lbl.gov [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)

    2015-07-01

    The capabilities and analytical benefits of combined LIBS and LA-ICP-MS were evaluated for the analysis of coal samples. The ablation system consisted of a Nd:YAG laser operated 213 nm. A Czerny-turner spectrograph with ICCD detector and time-of-flight based mass spectrometer were utilized for LIBS and ICP-MS detection, respectively. This tandem approach allows simultaneous determination of major and minor elements (C, Si, Ca, Al, Mg), and trace elements (V, Ba, Pb, U, etc.) in the coal samples. The research focused on calibration strategies, specifically the use of univariate and multivariate data analysis on analytical performance. Partial least square regression (PLSR) was shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The correlation between measurements from these two techniques demonstrated that mass spectral data combined with LIBS emission measurements by PLSR improved the accuracy and precision for quantitative analysis of trace elements in coal. - Highlights: • Tandem LIBS LA-ICP-MS • Simultaneous determination of major and minor elements and trace elements in the coal samples. • Extended Dynamic Range • Correlation between LIBS with LA-ICP-MS demonstrated improved the accuracy and precision for quantitative analysis of coal.

  15. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry characterization of aging effects on the mineral fibers treated with aminopropylsilane and quaternary ammonium compounds

    DEFF Research Database (Denmark)

    Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.

    2012-01-01

    X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to investigate the aging effects on the aminopropylsilane (APS) and quaternary ammonium surfactant-treated mineral fibers. APS-coated mineral fiber samples were treated with cationic surfactant...... (PCA) was applied to the time-of-flight secondary ion mass spectrometry spectra, and an increase in the intensities of APS characteristic peaks were observed after aging. The observed increase in the signals of APS originates from underlying silanized fibers after the removal of the surfactant...

  16. A New Approach for Combining Time-of-Flight and RGB Cameras Based on Depth-Dependent Planar Projective Transformations

    Directory of Open Access Journals (Sweden)

    Carlota Salinas

    2015-09-01

    Full Text Available Image registration for sensor fusion is a valuable technique to acquire 3D and colour information for a scene. Nevertheless, this process normally relies on feature-matching techniques, which is a drawback for combining sensors that are not able to deliver common features. The combination of ToF and RGB cameras is an instance that problem. Typically, the fusion of these sensors is based on the extrinsic parameter computation of the coordinate transformation between the two cameras. This leads to a loss of colour information because of the low resolution of the ToF camera, and sophisticated algorithms are required to minimize this issue. This work proposes a method for sensor registration with non-common features and that avoids the loss of colour information. The depth information is used as a virtual feature for estimating a depth-dependent homography lookup table (Hlut. The homographies are computed within sets of ground control points of 104 images. Since the distance from the control points to the ToF camera are known, the working distance of each element on the Hlut is estimated. Finally, two series of experimental tests have been carried out in order to validate the capabilities of the proposed method.

  17. Direct analysis of pharmaceutical drug formulations using ion mobility spectrometry/quadrupole-time-of-flight mass spectrometry combined with desorption electrospray ionization.

    Science.gov (United States)

    Weston, Daniel J; Bateman, Robert; Wilson, Ian D; Wood, Tim R; Creaser, Colin S

    2005-12-01

    A novel approach to the rapid analysis of pharmaceutical drug formulations using hyphenated ion mobility spectrometry (IMS) and time-of-flight mass spectrometry (ToF-MS) that requires no sample pretreatment or chromatographic separation is described. A modified quadrupole time-of-flight mass spectrometer containing an ion mobility drift cell was used for gas-phase electrophoretic separation of ions prior to ToF-MS detection. The generation of sample ions directly from tablets and cream formulations was effected by desorption electrospray ionization (DESI) using a modified electrospray ion source. The analysis of a range of over-the-counter and prescription tablet formulations is described, including histamine H2 receptor antagonist (ranitidine), analgesic (paracetamol), opiate (codeine), and aromatase inhibitor anticancer (anastrozole) drugs. The successful determination of active drugs from soft formulations, such as an antiseptic cream (chlorhexidine) and a nicotine-containing skin patch, is also presented. Limits of detection for the active drugs using the DESI/IMS/ToF-MS method fell within the high-picomole to nanomole range. In all cases, the use of ion mobility drift tube separation showed increased selectivity for active drug responses (present as low as 0.14% w/w) over excipient responses such as poly(ethylene glycol). Tandem mass spectrometric analysis of precursor ions separated by IMS allowed positive confirmation of active drugs with little loss of ion mobility efficiency. The ability to analyze hard or soft pharmaceutical formulations directly by DESI combined with ion mobility spectrometry/mass spectrometry in approximately 2 min demonstrates the potential applicability of this novel method to pharmaceutical screening of low-molecular-weight drug formulations with high selectivity over the formulation vehicle.

  18. Probing the orientation of electrostatically immobilized cytochrome C by time of flight secondary ion mass spectrometry and sum frequency generation spectroscopy.

    Science.gov (United States)

    Baio, Joe E; Weidner, Tobias; Ramey, Dennis; Pruzinsky, Leah; Castner, David G

    2013-12-01

    By taking advantage of the electron pathway through the heme group in cytochrome c (CytoC) electrochemists have built sensors based upon CytoC immobilized onto metal electrodes. Previous studies have shown that the electron transfer rate through the protein is a function of the position of this heme group with respect to the electrode surface. In this study a detailed examination of CytoC orientation when electrostatically immobilized onto both amine (NH3(+)) and carboxyl (COO(-)) functionalized gold is presented. Protein coverage, on both surfaces, was monitored by the change in the atomic % N, as determined by x-ray photoelectron spectroscopy. Spectral features within the in situ sum frequency generation vibrational spectra, acquired for the protein interacting with positively and negatively charged surfaces, indicates that these electrostatic interactions do induce the protein into a well ordered film. Time of flight secondary ion mass spectrometry data demonstrated a clear separation between the two samples based on the intensity differences of secondary ions stemming from amino acids located asymmetrically within CytoC (cysteine: C2H6NS(+); glutamic acid: C4H6NO(+) and C4H8NO2 (+); leucine: C5H12N(+)). For a more quantitative examination of orientation, we developed a ratio comparing the sum of the intensities of secondary-ions stemming from the amino acid residues at either end of the protein. The 50 % increase in this ratio, observed between the protein covered NH3 (+) and COO(-) substrates, indicates opposite orientations of the CytoC on the two different surfaces.

  19. Magnetic properties of nano-scale hematite, α-Fe2O3, studied by time-of-flight inelastic neutron spectroscopy

    DEFF Research Database (Denmark)

    Hill, Adrian H.; Jacobsen, Henrik Skåret; Stewart, J. Ross

    2014-01-01

    Samples of nanoscale hematite, α-Fe2O3, with different surface geometries and properties have been studied with inelastic time-of-flight neutron scattering. The 15 nm diameter nanoparticles previously shown to have two collective magnetic excitation modes in separate triple-axis neutron scatterin...

  20. Single photon ionization and chemical ionization combined ion source based on a vacuum ultraviolet lamp for orthogonal acceleration time-of-flight mass spectrometry.

    Science.gov (United States)

    Hua, Lei; Wu, Qinghao; Hou, Keyong; Cui, Huapeng; Chen, Ping; Wang, Weiguo; Li, Jinghua; Li, Haiyang

    2011-07-01

    A novel combined ion source based on a vacuum ultraviolet (VUV) lamp with both single photon ionization (SPI) and chemical ionization (CI) capabilities has been developed for an orthogonal acceleration time-of-flight mass spectrometer (oaTOFMS). The SPI was accomplished using a commercial 10.6 eV krypton discharge lamp with a photon flux of about 10(11) photons s(-1), while the CI was achieved through ion-molecule reactions with O(2)(+) reactant ions generated by photoelectron ionization at medium vacuum pressure (MVP). To achieve high ionization efficiency, the ion source pressure was elevated to 0.3 mbar and the photoionization length was extended to 36 mm. As a result, limits of detection (LODs) down to 3, 4, and 6 ppbv were obtained for benzene, toluene, and p-xylene in MVP-SPI mode, and values of 8 and 10 ppbv were obtained for toluene and chloroform, respectively, in SPI-CI mode. As it is feasible to switch between MVP-SPI mode and SPI-CI mode rapidly, this system is capable of monitoring complex organic mixtures with a wide range of ionization energies (IEs). The analytical capacity of this system was demonstrated by measuring dehydrogenation products of long-chain paraffins to olefins through direct capillary sampling and drinking water disinfection byproducts from chlorine through a membrane interface.

  1. First online multireflection time-of-flight mass measurements of isobar chains produced by fusion-evaporation reactions: Toward identification of superheavy elements via mass spectroscopy

    Science.gov (United States)

    Schury, P.; Wada, M.; Ito, Y.; Kaji, D.; Arai, F.; MacCormick, M.; Murray, I.; Haba, H.; Jeong, S.; Kimura, S.; Koura, H.; Miyatake, H.; Morimoto, K.; Morita, K.; Ozawa, A.; Rosenbusch, M.; Reponen, M.; Söderström, P.-A.; Takamine, A.; Tanaka, T.; Wollnik, H.

    2017-01-01

    Using a multireflection time-of-flight mass spectrograph located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several α -decaying heavy nuclei were directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectilelike and targetlike particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 204Fr-204Rn-204At-204Po , 205Fr-205Rn-205At-205Po-205Bi , and 206Fr-206Rn-206At , were observed. Precision atomic mass values were determined for Fr-206204, Rn,205204, and At,205204. Identifications of 205Bi, Po,205204, 206Rn, and 206At were made with N ≲10 detected ions, representing the next step toward use of mass spectrometry to identify exceedingly low-yield species such as superheavy element ions.

  2. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Combined Species Identification and Drug Sensitivity Testing in Mycobacteria.

    Science.gov (United States)

    Ceyssens, Pieter-Jan; Soetaert, Karine; Timke, Markus; Van den Bossche, An; Sparbier, Katrin; De Cremer, Koen; Kostrzewa, Markus; Hendrickx, Marijke; Mathys, Vanessa

    2017-02-01

    Species identification and drug susceptibility testing (DST) of mycobacteria are important yet complex processes traditionally reserved for reference laboratories. Recent technical improvements in matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has started to facilitate routine mycobacterial identifications in clinical laboratories. In this paper, we investigate the possibility of performing phenotypic MALDI-based DST in mycobacteriology using the recently described MALDI Biotyper antibiotic susceptibility test rapid assay (MBT-ASTRA). We randomly selected 72 clinical Mycobacterium tuberculosis and nontuberculous mycobacterial (NTM) strains, subjected them to MBT-ASTRA methodology, and compared its results to current gold-standard methods. Drug susceptibility was tested for rifampin, isoniazid, linezolid, and ethambutol (M. tuberculosis, n = 39), and clarithromycin and rifabutin (NTM, n = 33). Combined species identification was performed using the Biotyper Mycobacteria Library 4.0. Mycobacterium-specific MBT-ASTRA parameters were derived (calculation window, m/z 5,000 to 13,000, area under the curve [AUC] of >0.015, relative growth [RG] of drug resistance profiles which corresponded to standard testing results. Turnaround times were not significantly different in M. tuberculosis testing, but the MBT-ASTRA method delivered on average a week faster than routine DST in NTM. Databases searches returned 90.4% correct species-level identifications, which increased to 98.6% when score thresholds were lowered to 1.65. In conclusion, the MBT-ASTRA technology holds promise to facilitate and fasten mycobacterial DST and to combine it directly with high-confidence species-level identifications. Given the ease of interpretation, its application in NTM typing might be the first in finding its way to current diagnostic workflows. However, further validations and automation are required before routine implementation can be envisioned

  3. Quantitative analysis of amino acids and acylcarnitines combined with untargeted metabolomics using ultra-high performance liquid chromatography and quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Roy, Cynthia; Tremblay, Pierre-Yves; Bienvenu, Jean-François; Ayotte, Pierre

    2016-08-01

    Metabolomics is an "omic" technique being increasingly used in epidemiological and clinical studies. We developed a method combining untargeted metabolomics with the quantitative determination of eight amino acids (AA) and eight acylcarnitines (AC) in plasma using ultra-high pressure liquid chromatography (UHPLC), electrospray ionization (ESI) and quadrupole time-of-flight mass spectrometry (QTOFMS). Separation of metabolites is performed by ion-pair reverse phase UHPLC using a HSS T3 column (2.1×100mm, 100Å, 1.8μm particle size) and formic acid-ammonium acetate-heptafluorobutyric acid in water and formic acid-ammonium acetate in methanol as mobile phases. Metabolite identification and quantification are achieved using a QTOFMS operating in ESI-positive and full-scan mode along with MS(E) acquisition of fragmentation patterns. Targeted metabolites are quantified using the appropriate labeled standards and include branched-chain AA (leucine, isoleucine, valine), aromatic AA (phenylalanine, tyrosine) as well as acetylcarnitine and propionylcarnitine, which have been identified as biomarkers of future cardiometabolic disease risk. The inter-day precision (relative standard deviation) for the targeted method was <15% for all but one metabolite and accuracy (bias) of amino acids ranged from 0.5% to 13.9% using SRM 1950 as the external standard. Untargeted metabolomics in 30 plasma samples from the general Canadian population revealed 5018 features, of which 48 metabolites were identified using the MZmine 2.19 software including 23 by our in-house library that comprises 671 annotated metabolites. SRM 1950 analysis revealed 11,684 features, among which 154 metabolites were identified. Our method is currently applied in several epidemiological studies to better characterize cardiometabolic diseases and identify new biomarkers for disease prevention. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Metabolism of olaquindox in rat liver microsomes: structural elucidation of metabolites by high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry.

    Science.gov (United States)

    Liu, Zhaoying; Huang, Lingli; Dai, Menghong; Chen, Dongmei; Wang, Yulian; Tao, Yanfei; Yuan, Zonghui

    2008-04-01

    Olaquindox (N-(2-hydroxyethyl)-3-methyl-2-quinoxalincarboxamide-1,4-dioxide) is a growth-promoting feed additive for food-producing animals. Its toxicity is closely related to the metabolism. The complete metabolic pathways of olaquindox are not revealed. To improve studies of the metabolism and toxicity of olaquindox, its biotransformation in rat liver microsomes and the structure of its metabolites using high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF) were investigated. When olaquindox was incubated with an NADPH-generating system and rat liver microsomes, ten metabolites (M1-M10) were detected. The structures of these metabolites were identified from mass spectra and comparison of their changes in their accurate molecular masses and fragment ions with those of the parent drug. With the high resolution and good mass accuracy achieved by this technique, the elemental compositions of the metabolites and their fragment ions were exactly determined. The results indicate that the N --> O group reduction is the main metabolic pathway of olaquindox metabolism in rat liver microsomes, because abundant 1-desolaquindox (M2), 4-desolaquindox (M1) and bisdesoxyolaquindox (M9) were produced during the incubation step. Seven other minor metabolites were revealed which were considered to be hydroxylation metabolites, based on the position of the quinoxaline ring or 3-methyl group and a carboxylic acid derivative on the side chain at position 2 of the quinoxaline ring. Among the identified metabolites, five new hydroxylated metabolites (M3-M7) were found for the first time in rat liver microsomes. This work will conduce to complete clarification of olaquindox metabolism, and improve the in vivo metabolism of olaquindox in food animals.

  5. Solid phase extraction in combination with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry for the detailed investigation of volatiles in South African red wines

    NARCIS (Netherlands)

    Weldegergis, B.T.; Crouch, A.M.; Górecki, T.; Villiers, de A.

    2011-01-01

    Comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC × GC–TOFMS) has been applied for the analysis of volatile compounds in three young South African red wines. In spite of the significant benefits offered by GC × GC–TOFMS for the separation and

  6. Trace metal analysis in arctic aerosols by an inductively coupled plasma-time of flight-mass spectrometer combined with an inductively heated vaporizer

    Energy Technology Data Exchange (ETDEWEB)

    Luedke, Christian [ISAS - Institute for Analytical Sciences, Department Berlin, Albert-Einstein-Str. 9, 12489 Berlin (Germany)]. E-mail: luedke@ansci.de; Skole, Jochen [ISAS - Institute for Analytical Sciences, Department Berlin, Albert-Einstein-Str. 9, 12489 Berlin (Germany); Taubner, Kerstin [ISAS - Institute for Analytical Sciences, Department Berlin, Albert-Einstein-Str. 9, 12489 Berlin (Germany); Kriews, Michael [Alfred Wegener Institute for Polar- and Marine Research, Am Handelshafen 12, 27570 Bremerhaven (Germany)

    2005-11-15

    Two newly developed instruments were combined to analyze the trace metal content in size separated arctic aerosols during the measurement campaign ASTAR 2004 (Arctic Study of Tropospheric Aerosols, Clouds and Radiation 2004) at Spitsbergen in May-June 2004. The aim of this extensive aerosol measurement campaign was to obtain a database for model-calculations of arctic aerosol, which play an important role in the global climate change. The ASTAR project was centered on two aircraft measurement campaigns, scheduled from 2004 to 2005, addressing both aerosol and cloud measurements, combined with ground-based and satellite observations. In the present paper one example for the analysis of ground-based aerosol particles is described. The sampling of aerosol particles was performed in a well-known manner by impaction of the particles on cleaned graphite targets. By means of a cascade impactor eight size classes between 0.35 and 16.6 {mu}m aerodynamic diameters were separated. To analyze the metal content in the aerosol particles the targets were rapidly heated up to 2700 deg. C in an inductively heated vaporizer system (IHVS). An argon flow transports the vaporized sample material into the inductively coupled plasma (ICP) used as ionization source for the time of flight-mass spectrometer (TOF-MS). The simultaneous extraction of the ions from the plasma, as realized in the TOF instrument, allows to obtain the full mass spectrum of the sample during the vaporization pulse without any limitation in the number of elements detected. With optimized experimental parameters the element content in arctic aerosol particles was determined in a mass range between {sup 7}Li and {sup 209}Bi. Comparing the size distribution of the elemental content of the aerosol particles, two different meteorological situations were verified. For calibration acidified reference solutions were placed on the cleaned target inside the IHVS. The limits of detection (LOD) for the element mass on the

  7. ALICE Time Of Flight Detector

    CERN Multimedia

    Alici, A

    2013-01-01

    Charged particles in the intermediate momentum range are identified in ALICE by the Time Of Flight (TOF) detector. The time measurement with the TOF, in conjunction with the momentum and track length measured by the tracking detector, is used to calculate the particle mass.

  8. Broadband photon time-of-flight spectroscopy of pharmaceuticals and highly scattering plastics in the VIS and close NIR spectral ranges.

    Science.gov (United States)

    Khoptyar, Dmitry; Subash, Arman Ahamed; Johansson, Sören; Saleem, Muhammad; Sparén, Anders; Johansson, Jonas; Andersson-Engels, Stefan

    2013-09-01

    We present extended spectroscopic analysis of pharmaceutical tablets in the close near infrared spectral range performed using broadband photon time-of-flight (PTOF) absorption and scattering spectra measurements. We show that the absorption spectra can be used to perform evaluation of the chemical composition of pharmaceutical tablets without need for chemo-metric calibration. The spectroscopic analysis was performed using an advanced PTOF spectrometer operating in the 650 to 1400 nm spectral range. By employing temporal stabilization of the system we achieve the high precision of 0.5% required to evaluate the concentration of tablet ingredients. In order to further illustrate the performance of the system, we present the first ever reported broadband evaluation of absorption and scattering spectra from pure and doped Spectralon®.

  9. High mass resolution, high angular acceptance time-of-flight mass spectroscopy for planetary missions under the Planetary Instrument Definition and Development Program (PIDDP)

    Science.gov (United States)

    Young, David T.

    1991-01-01

    This final report covers three years and several phases of work in which instrumentation for the Planetary Instrument Definition and Development Program (PIDDP) were successfully developed. There were two main thrusts to this research: (1) to develop and test methods for electrostatically scanning detector field-of-views, and (2) to improve the mass resolution of plasma mass spectrometers to M/delta M approximately 25, their field-of-view (FOV) to 360 degrees, and their E-range to cover approximately 1 eV to 50 keV. Prototypes of two different approaches to electrostatic scanning were built and tested. The Isochronous time-of-flight (TOF) and the linear electric field 3D TOF devices were examined.

  10. Magnetic properties of nano-scale hematite, α-Fe2O3, studied by time-of-flight inelastic neutron spectroscopy.

    Science.gov (United States)

    Hill, Adrian H; Jacobsen, Henrik; Stewart, J Ross; Jiao, Feng; Jensen, Niels P; Holm, Sonja L; Mutka, Hannu; Seydel, Tilo; Harrison, Andrew; Lefmann, Kim

    2014-01-28

    Samples of nanoscale hematite, α-Fe2O3, with different surface geometries and properties have been studied with inelastic time-of-flight neutron scattering. The 15 nm diameter nanoparticles previously shown to have two collective magnetic excitation modes in separate triple-axis neutron scattering studies have been studied in further detail using the advantage of a large detector area, high resolution, and large energy transfer range of the IN5 TOF spectrometer. A mesoporous hematite sample has also been studied, showing similarities to that of the nanoparticle sample and bulk α-Fe2O3. Analysis of these modes provides temperature dependence of the magnetic anisotropy coefficient along the c-axis, κ1. This is shown to remain negative throughout the temperature range studied in both samples, providing an explanation for the previously observed suppression of the Morin transition in the mesoporous material. The values of this anisotropy coefficient are found to lie between those of bulk and nano-particulate samples, showing the hybrid nature of the mesoporous 3-dimensional structure.

  11. Detection of bacteria from biological mixtures using immunomagnetic separation combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    Science.gov (United States)

    Madonna, A.J.; Basile, F.; Furlong, E.; Voorhees, K.J.

    2001-01-01

    A rapid method for identifying specific bacteria from complex biological mixtures using immunomagnetic separation coupled to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been developed. The technique employs commercially available magnetic beads coated with polycolonal antibodies raised against specific bacteria and whole cell analysis by MALDI-MS. A suspension of a bacterial mixture is mixed with the immunomagnetic beads specific for the target microorganism. After a short incubation period (20 mins) the bacteria captured by the beads are washed, resuspended in deionized H2O and directly applied onto a MALDI probe. Liquid suspensions containing bacterial mixtures can be screened within 1 h total analysis time. Positive tests result in the production of a fingerprint mass spectrum primarily consisting of protein biomarkers characteristic of the targeted microorganism. Using this procedure, Salmonella choleraesuis was isolated and detected from standard bacterial mixtures and spiked samples of river water, human urine, and chicken blood. Copyright ?? 2001 John Wiley & Sons, Ltd.

  12. Combination of quantitative analysis and chemometric analysis for the quality evaluation of three different frankincenses by ultra high performance liquid chromatography and quadrupole time of flight mass spectrometry.

    Science.gov (United States)

    Zhang, Chao; Sun, Lei; Tian, Run-tao; Jin, Hong-yu; Ma, Shuang-Cheng; Gu, Bing-ren

    2015-10-01

    Frankincense has gained increasing attention in the pharmaceutical industry because of its pharmacologically active components such as boswellic acids. However, the identity and overall quality evaluation of three different frankincense species in different Pharmacopeias and the literature have less been reported. In this paper, quantitative analysis and chemometric evaluation were established and applied for the quality control of frankincense. Meanwhile, quantitative and chemometric analysis could be conducted under the same analytical conditions. In total 55 samples from four habitats (three species) of frankincense were collected and six boswellic acids were chosen for quantitative analysis. Chemometric analyses such as similarity analysis, hierarchical cluster analysis, and principal component analysis were used to identify frankincense of three species to reveal the correlation between its components and species. In addition, 12 chromatographic peaks have been tentatively identified explored by reference substances and quadrupole time-of-flight mass spectrometry. The results indicated that the total boswellic acid profiles of three species of frankincense are similar and their fingerprints can be used to differentiate between them.

  13. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry characterization of aging effects on the mineral fibers treated with aminopropylsilane and quaternary ammonium compounds

    DEFF Research Database (Denmark)

    Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.

    2012-01-01

    -resolution spectra is also observed. These results indicate that the concentration of hydrocarbon groups decreases after aging due to the partial removal of the long hydrocarbon chains of the surfactant and mineral oil and/or hydrolysis and segregation of APS to the fiber surface. The principal component analysis......X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to investigate the aging effects on the aminopropylsilane (APS) and quaternary ammonium surfactant-treated mineral fibers. APS-coated mineral fiber samples were treated with cationic surfactant...... and mineral oil and aged at 70 °C temperature and 95% humidity. From quantitative XPS measurements, an increase in the atomic composition of oxygen, nitrogen, and silicon is observed after aging. An increase in the protonated amino groups in the N1s high-resolution spectra and C–N group in the C1s high...

  14. Single-Crystal Time-of-Flight Neutron Diffraction and Magic-Angle-Spinning NMR Spectroscopy Resolve the Structure and (1)H and (7)Li Dynamics of the Uranyl Peroxide Nanocluster U60.

    Science.gov (United States)

    Olds, Travis A; Dembowski, Mateusz; Wang, Xiaoping; Hoffman, Christina; Alam, Todd M; Hickam, Sarah; Pellegrini, Kristi L; He, Junhong; Burns, Peter C

    2017-08-21

    Single-crystal time-of-flight neutron diffraction has provided atomic resolution of H atoms of H2O molecules and hydroxyl groups, as well as Li cations in the uranyl peroxide nanocluster U60. Solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy was used to confirm the dynamics of these constituents, revealing the transportation of Li atoms and H2O through cluster walls. H atoms of hydroxyl units that are located on the cluster surface are involved in the transfer of H2O and Li cations from inside to outside and vice versa. This exchange occurs as a concerted motion and happens rapidly even in the solid state. As a consequence of its large size and open hexagonal pores, U60 exchanges Li cations more rapidly compared to other uranyl nanoclusters.

  15. Lu.sub.1-xI.sub.3:Ce.sub.x-a scintillator for gamma-ray spectroscopy and time-of-flight pet

    Science.gov (United States)

    Shah, Kanai S [Newton, MA

    2008-02-12

    The present invention includes very fast scintillator materials including lutetium iodide doped with Cerium (Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma-ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma-ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration.

  16. Lu.sub.1-xI.sub.3:Ce.sub.x-a scintillator for gamma-ray spectroscopy and time-of-flight pet

    Science.gov (United States)

    Shah, Kanai S.

    2008-02-12

    The present invention includes very fast scintillator materials including lutetium iodide doped with Cerium (Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma-ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma-ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration.

  17. Avalanche photodiode based time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Keiichi, E-mail: kogasawara@swri.edu; Livi, Stefano A.; Desai, Mihir I.; Ebert, Robert W.; McComas, David J.; Walther, Brandon C. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238 (United States)

    2015-08-15

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1−40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  18. Avalanche photodiode based time-of-flight mass spectrometry.

    Science.gov (United States)

    Ogasawara, Keiichi; Livi, Stefano A; Desai, Mihir I; Ebert, Robert W; McComas, David J; Walther, Brandon C

    2015-08-01

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1-40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  19. Lu.sub.1-xI.sub.3:Ce.sub.x--a scintillator for gamma ray spectroscopy and time-of-flight PET

    Science.gov (United States)

    Shah, Kanai S.

    2007-02-06

    The present invention concerns very fast scintillator materials comprising lutetium iodide doped with Cerium (Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration. The timing resolution of the scintillators of the present invention provide compositions capable of resolving the position of an annihilation event within a portion of a human body cross-section.

  20. Doppler time-of-flight imaging

    KAUST Repository

    Heide, Felix

    2015-07-30

    Over the last few years, depth cameras have become increasingly popular for a range of applications, including human-computer interaction and gaming, augmented reality, machine vision, and medical imaging. Many of the commercially-available devices use the time-of-flight principle, where active illumination is temporally coded and analyzed on the camera to estimate a per-pixel depth map of the scene. In this paper, we propose a fundamentally new imaging modality for all time-of-flight (ToF) cameras: per-pixel velocity measurement. The proposed technique exploits the Doppler effect of objects in motion, which shifts the temporal frequency of the illumination before it reaches the camera. Using carefully coded illumination and modulation frequencies of the ToF camera, object velocities directly map to measured pixel intensities. We show that a slight modification of our imaging system allows for color, depth, and velocity information to be captured simultaneously. Combining the optical flow computed on the RGB frames with the measured metric axial velocity allows us to further estimate the full 3D metric velocity field of the scene. We believe that the proposed technique has applications in many computer graphics and vision problems, for example motion tracking, segmentation, recognition, and motion deblurring.

  1. The TORCH time-of-flight detector

    Energy Technology Data Exchange (ETDEWEB)

    Harnew, N., E-mail: Neville.Harnew@physics.ox.ac.uk [University of Oxford, Denys Wilkinson Building, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Brook, N. [University College London, Department of Physics & Astronomy, Gower Street, London WC1E 6BT (United Kingdom); Castillo García, L. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Laboratory for High Energy Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Cussans, D. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom); Föhl, K.; Forty, R.; Frei, C. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Gao, R. [University of Oxford, Denys Wilkinson Building, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Gys, T.; Piedigrossi, D. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Rademacker, J.; Ros Garcia, A.; Dijk, M. van [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

    2016-07-11

    The TORCH time-of-flight detector is being developed to provide particle identification between 2 and 10 GeV/c momentum over a flight distance of 10 m. TORCH is designed for large-area coverage, up to 30 m{sup 2}, and has a DIRC-like construction. The goal is to achieve a 15 ps time-of-flight resolution per incident particle by combining arrival times from multiple Cherenkov photons produced within quartz radiator plates of 10 mm thickness. A four-year R&D programme is underway with an industrial partner (Photek, UK) to produce 53×53 mm{sup 2} Micro-Channel Plate (MCP) detectors for the TORCH application. The MCP-PMT will provide a timing accuracy of 40 ps per photon and it will have a lifetime of up to at least 5 Ccm{sup −2} of integrated anode charge by utilizing an Atomic Layer Deposition (ALD) coating. The MCP will be read out using charge division with customised electronics incorporating the NINO chipset. Laboratory results on prototype MCPs are presented. The construction of a prototype TORCH module and its simulated performance are also described.

  2. Hadamard Transform Time-of-Flight Spectroscopy

    Science.gov (United States)

    2010-01-26

    system presented in Figure 13 were determined by direct fitting of the initial rates data to the Michaelis - Menten equation. Excellent agreement is...trypsin at pH 8.5. The dashed red line in the figure shows a best fit to the Michaelis - Menten equation for the data collected. The error bars in

  3. Towards Surface Plasmon Resonance biosensing combined with bioaffinity-assisted nano HILIC Liquid Chromatography / Time-of-flight Mass Spectrometry identification of Paralytic Shellfish Poisons

    NARCIS (Netherlands)

    Marchesini, G.R.; Hooijerink, H.; Haasnoot, W.; Buijs, J.; Campbell, K.; Elliott, C.T.; Nielen, M.W.F.

    2009-01-01

    The potential for coupling technologies to deliver new, improved forms of bioanalysis is still in its infancy. We review a number of examples in which coupling has been successful, with special emphasis on combining surface-plasmon-resonance biosensors with mass spectrometry. We give an overview of

  4. Analysis of the Constituents in “Zhu She Yong Xue Shuan Tong” by Ultra High Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry Combined with Preparative High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-11-01

    Full Text Available “Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST, consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS combined with preparative high performance liquid chromatography (PHPLC method was developed to rapidly identify both major and minor saponins in ZSYXST. Some high content components were removed through PHPLC in order to increase the sensitivity of the trace saponins. Then, specific characteristic fragment ions in both positive and negative mode were utilized to determine the types of aglycone, saccharide, as well as the saccharide chain linkages. As a result, 94 saponins, including 20 pairs of isomers and ten new compounds, which could represent higher than 98% components in ZSYXST, were identified or tentatively identified in commercial ZSYXST samples.

  5. Impact of rapid identification of Acinetobacter Baumannii via matrix-assisted laser desorption ionization time-of-flight mass spectrometry combined with antimicrobial stewardship in patients with pneumonia and/or bacteremia.

    Science.gov (United States)

    Wenzler, Eric; Goff, Debra A; Mangino, Julie E; Reed, Erica E; Wehr, Allison; Bauer, Karri A

    2016-01-01

    We evaluated the clinical and economic outcomes of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) with stewardship intervention in patients with Acinetobacter baumannii (AB) pneumonia and/or bacteremia. 66 patients were included in the pre-intervention group and 53 in the intervention group. The combination of AB identification via MALDI-TOF MS and ID PharmD intervention significantly reduced the median time to effective therapy compared to conventional identification without intervention [77.7 (95% CI: 73.1-84.8) to 36.6 (95% CI: 25.9-50.9) hours (P timely, effective antimicrobial therapy and is associated with increased clinical cure.

  6. Combined data mining strategy for the systematic identification of sport drug metabolites in urine by liquid chromatography time-of-flight mass spectrometry.

    Science.gov (United States)

    Domínguez-Romero, Juan C; García-Reyes, Juan F; Martínez-Romero, Rubén; Berton, Paula; Martínez-Lara, Esther; Del Moral-Leal, María L; Molina-Díaz, Antonio

    2013-01-25

    The development of comprehensive methods able to tackle with the systematic identification of drug metabolites in an automated fashion is of great interest. In this article, a strategy based on the combined use of two complementary data mining tools is proposed for the screening and systematic detection and identification of urinary drug metabolites by liquid chromatography full-scan high resolution mass spectrometry. The proposed methodology is based on the use of accurate mass extraction of diagnostic ions (compound-dependent information) from in-source CID fragmentation without precursor ion isolation along with the use of automated mass extraction of accurate-mass shifts corresponding to typical biotransformations (non compound-dependent information) that xenobiotics usually undergo when metabolized. The combined strategy was evaluated using LC-TOFMS with a suite of nine sport drugs representative from different classes (propranolol, bumetanide, clenbuterol, ephedrine, finasteride, methoxyphenamine, methylephedrine, salbutamol and terbutaline), after single doses administered to rats. The metabolite identification coverage rate obtained with the systematic method (compared to existing literature) was satisfactory, and provided the identification of several non-previously reported metabolites. In addition, the combined information obtained helps to minimize the number of false positives. As an example, the systematic identification of urinary metabolites of propranolol enabled the identification of up to 24 metabolites, 15 of them non previously described in literature, which is a valuable indicator of the usefulness of the proposed systematic procedure.

  7. Analytical properties of time-of-flight PET data

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sanghee; Ahn, Sangtae; Li Quanzheng; Leahy, Richard M [Signal and Image Processing Institute, University of Southern California, Los Angeles, CA 90089 (United States)], E-mail: leahy@sipi.usc.edu

    2008-06-07

    We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

  8. Analytical properties of time-of-flight PET data

    Science.gov (United States)

    Cho, Sanghee; Ahn, Sangtae; Li, Quanzheng; Leahy, Richard M.

    2008-06-01

    We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

  9. Analytical properties of time-of-flight PET data.

    Science.gov (United States)

    Cho, Sanghee; Ahn, Sangtae; Li, Quanzheng; Leahy, Richard M

    2008-06-07

    We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

  10. Inexpensive Time-of-Flight Velocity Measurements.

    Science.gov (United States)

    Everett, Glen E.; Wild, R. L.

    1979-01-01

    Describes a circuit designed to measure time-of-flight velocity and shows how to use it to determine bullet velocity in connection with the ballistic pendulum demonstration of momentum conservation. (Author/GA)

  11. Neutron Time-Of-Flight (n_TOF) experiment

    CERN Multimedia

    Brugger, M; Jericha, E; Cortes rossell, G P; Riego perez, A; Baccomi, R; Laurent, B G; Palomo pinto, F R; Griesmayer, E; Leeb, H; Dressler, M; Cano ott, D; Variale, V; Ventura, A; Carrillo de albornoz trillo, A; Lo meo, S; Andrzejewski, J J; Pavlik, A F; Kadi, Y; Zanni vlastou, R; Krticka, M; Weiss, C; Kokkoris, M; Praena rodriguez, A J; Cortes giraldo, M A; Perkowski, J; Losito, R; Audouin, L; Tagliente, G; Wallner, A; Woods, P J; Mengoni, A; Guerrero sanchez, C G; Tain enriquez, J L; Vlachoudis, V; Calviani, M; Reifarth, R; Mendoza cembranos, E; Quesada molina, J M; Schumann, M D; Tsinganis, A; Saxena, A; Rauscher, T; Calvino tavares, F; Bondarenko, I; Mingrone, F; Gonzalez romero, E M; Colonna, N; Negret, A L; Leal cidoncha, E; Chiaveri, E; Milazzo, P M; Ferro pereira goncalves, I M; De almeida carrapico, C A; Castelluccio, D M

    The neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.

  12. Yersinia enterocolitica in diagnostic fecal samples from European dogs and cats: identification by fourier transform infrared spectroscopy and matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Stamm, Ivonne; Hailer, Mandy; Depner, Barbara; Kopp, Peter A; Rau, Jörg

    2013-03-01

    Yersinia enterocolitica is the main cause of yersiniosis in Europe, one of the five main bacterial gastrointestinal diseases of humans. Beside pigs, companion animals, especially dogs and cats, were repeatedly discussed in the past as a possible source of pathogenic Y. enterocolitica. To investigate the presence and types of Y. enterocolitica in companion animals, a total of 4,325 diagnostic fecal samples from dogs and 2,624 samples from cats were tested. The isolates obtained were differentiated by using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and Fourier transform infrared spectroscopy (FT-IR). Isolated Y. enterocolitica strains were bioserotyped. The detection of the ail gene by PCR and confirmation by FT-IR were used as a pathogenicity marker. Y. enterocolitica strains were isolated from 198 (4.6%) of the dog and 8 (0.3%) of the cat fecal samples investigated. One hundred seventy-nine isolates from dogs were analyzed in detail. The virulence factor Ail was detected in 91.6% of isolates. Isolates of biotype 4 (54.7%) and, to a lesser extent, biotypes 2 (23.5%), 3 (11.2%), and 5 (2.2%) were detected. The remaining 8.4% of strains belonged to the ail-negative biotype 1A. All 7 isolates from cats that were investigated in detail were ail positive. These results indicate that companion animals could be a relevant reservoir for a broad range of presumptively human-pathogenic Y. enterocolitica types. MALDI-TOF MS and FT-IR proved to be valuable methods for the rapid identification of Y. enterocolitica, especially in regard to the large number of samples that were investigated in a short time frame.

  13. Probing the orientation of electrostatically immobilized Protein G B1 by time-of-flight secondary ion spectrometry, sum frequency generation, and near-edge X-ray adsorption fine structure spectroscopy.

    Science.gov (United States)

    Baio, Joe E; Weidner, Tobias; Baugh, Loren; Gamble, Lara J; Stayton, Patrick S; Castner, David G

    2012-01-31

    To fully develop techniques that provide an accurate description of protein structure at a surface, we must start with a relatively simple model system before moving to increasingly complex systems. In this study, X-ray photoelectron spectroscopy (XPS), sum frequency generation spectroscopy (SFG), near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to probe the orientation of Protein G B1 (6 kDa) immobilized onto both amine (NH(3)(+)) and carboxyl (COO(-)) functionalized gold. Previously, we have shown that we could successfully control orientation of a similar Protein G fragment via a cysteine-maleimide bond. In this investigation, to induce opposite end-on orientations, a charge distribution was created within the Protein G B1 fragment by first substituting specific negatively charged amino acids with neutral amino acids and then immobilizing the protein onto two oppositely charged self-assembled monolayer (SAM) surfaces (NH(3)(+) and COO(-)). Protein coverage, on both surfaces, was monitored by the change in the atomic % N, as determined by XPS. Spectral features within the SFG spectra, acquired for the protein adsorbed onto a NH(3)(+)-SAM surface, indicates that this electrostatic interaction does induce the protein to form an oriented monolayer on the SAM substrate. This corresponded to the polarization dependence of the spectral feature related to the NEXAFS N(1s)-to-π* transition of the β-sheet peptide bonds within the protein layer. ToF-SIMS data demonstrated a clear separation between the two samples based on the intensity differences of secondary ions stemming from amino acids located asymmetrically within Protein G B1 (methionine: 62 and 105 m/z; tyrosine: 107 and 137 m/z; leucine: 86 m/z). For a more quantitative examination of orientation, we developed a ratio comparing the sum of the intensities of secondary-ions stemming from the amino acid residues at either end

  14. Formation of ketene (H{sub 2}CCO) in interstellar analogous methane (CH{sub 4})-carbon monoxide (CO) ices: A combined FTIR and reflectron time-of-flight mass spectroscopic study

    Energy Technology Data Exchange (ETDEWEB)

    Maity, Surajit; Kaiser, Ralf I.; Jones, Brant M. [W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii, HI 96822 (United States)

    2014-07-01

    The formation of ketene (H{sub 2}CCO) in methane-carbon monoxide (CH{sub 4}-CO) ices was investigated upon its exposure to ionizing radiation in the form of energetic electrons at 5.5 K. The radiation-induced nonthermal equilibrium processing of these ices was monitored online and in situ via infrared spectroscopy complimented with post-irradiation temperature programmed desorption studies exploiting highly sensitive reflectron time-of-flight mass spectrometry (ReTOF) coupled with single photon fragment-free photo ionization (PI) at 10.49 eV. The detection of ketene in irradiated (isotopically labeled) methane-carbon monoxide ices was confirmed via the ν{sub 2} infrared absorption band and substantiated during the warm-up phase based on sublimation profiles obtained from the ReTOF-PI spectra of the corresponding isotopic masses. The experiments conducted with the mixed isotopic ices of {sup 12}CD{sub 4}-{sup 13}CO provide clear evidence of the formation of at least two ketene isotopomers (D{sub 2} {sup 12}C{sup 13}CO and D{sub 2} {sup 13}C{sup 13}CO), allowing for the derivation of two competing formation pathways. We have also proposed underlying reaction mechanisms to the formation of ketene based on kinetic fitting of the temporal evolution of the ketene isotopomers.

  15. Imipenem-avibactam: a novel combination for the rapid detection of carbapenemase activity in Enterobacteriaceae and Acinetobacter baumannii by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Oviaño, Marina; Bou, Germán

    2017-02-01

    In the present study, we propose a novel matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based method for detecting carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii. For this, we analyzed a series of 131 isolates. Among them, a total of 115 Enterobacteriaceae: 79 of them carrying a carbapenemase enzyme (15blaKPC, 7blaNDM, 11blaIMP, 12blaVIM, and 34blaOXA-48) and 16 A. baumannii isolates: 15 of them carrying carbapenemases (10blaOXA-23, 2blaOXA-58, 2blaOXA-24, and 1blaOXA-237). The rest of the isolates were noncarbapenemase producers and used as negative controls. The isolates were submitted to susceptibility testing using a combination of imipenem-avibactam and analysis by the MALDI-TOF Biotyper Compass software (Bruker Daltonik, Germany). The assay showed an overall sensitivity and specificity for carbapenemase detection of 98% and 100%, respectively. The combination of imipenem and avibactam displayed activity against KPC and OXA-48-producing Enterobacteriaceae and thus represents a new strategy for identifying and confirming these carbapenemases. However, the combination did not provide any benefit over A. baumannii.

  16. Combined use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) and high performance liquid chromatography with photodiode array detector (HPLC-DAD) in systematic toxicological analysis.

    Science.gov (United States)

    Broecker, Sebastian; Pragst, Fritz; Bakdash, Abdulsallam; Herre, Sieglinde; Tsokos, Michael

    2011-10-10

    Time of flight mass spectrometry provides new possibilities of substance identification by determination of the molecular formula from accurate molecular mass and isotope pattern. However, the huge number of possible isomers requires additional evidence. As a suitable way for routine performance of systematic toxicological analysis, a method for combined use of liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) and high performance liquid chromatography with diode array detector (HPLC-DAD) was developed and applied to blood samples from 77 death cases. The blood samples were prepared by extraction with CH(2)Cl(2) and by protein precipitation with acetonitrile (1:4 (v/v)). The evaporated extracts were reconstituted in 35% acetonitril/0.1% formic acid/H(2)O and aliquots were injected for analysis by LC-QTOF-MS (Agilent 6530) and HPLC-DAD (Agilent 1200). A valve switching system enabled simultaneous operation of both separated chromatographic lines under their respective optimal conditions using the same autosampler. The ESI-QTOF-MS instrument was run in data dependent acquisition mode with switching between MS and MS/MS (cycle time 1.1s) and measuring the full mass spectra and the collision induced dissociation (CID) fragment spectra of all essential [M+H](+) ions. Libraries of accurate mass CID spectra (~2500 substances) and of DAD-UV spectra (~3300 substances) of the authors were used for substance identification. The application of this procedure is demonstrated in detail at four examples with multiple drug intake or administration. In the 77 cases altogether 198 substances were identified (87 by DAD and 195 by QTOF-MS) with a frequency between 1 and 20. In practical application, the sample preparation proved to be suitable for both techniques and for a wide variety of substances with different polarity. The automatic performance of the measurements was efficient and robust. Mutual confirmation, decrease of false positive and

  17. Identification and quantification of the anti-inflammatory constituents in Pian-Tze-Huang by liquid chromatography combined with quadrupole time-of-flight and triple quadrupole mass spectrometry.

    Science.gov (United States)

    Huang, Mingqing; Xu, Wen; Zhang, Yiping; Liu, Jie; Zhang, Xiaoqin; Lin, Jing; Peng, Jun; Lu, Jinjian

    2016-08-01

    Both qualitative and quantitative analyses combined with activity evaluation were used for the integrated quality control study of Pien-Tze-Huang (PZH), a precious lozenge used for 460 years in China. In qualitative analysis, a high performance LC-quadrupole time-of-flight MS method was developed for the identification of chemical profiling in PZH. 27 compounds were unambiguously identified by comparing with reference substances, and 12 compounds were tentatively deduced based on their MS data and comparing with literatures. Then the in vitro anti-inflammatory activity of 27 compounds were evaluated, and 9 saponins, 11 bile acids, taurine and muscone exhibited significant inhibitory activities on TNF-α production with IC50 values ranging from 12.34 to 147.24μM. In quantitative analysis, 21 active compounds, selected as quality control markers, were simultaneously detected in 15 batches of PZH samples by ultra-performance LC-triple quadrupole MS. All the analytes were detected within 15min. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r(2)>0.9990). The respective relative standard deviations of intra- and inter-day precisions, repeatability, stability, and recovery were less than 4.32%, 4.94%, 4.78%, 4.87%, and 4.91%. This study established a high sensitive and efficient method for the integrated quality control of PZH, including qualitative and quantitative analyses combined with pharmacological activity evaluation.

  18. Metabolomics Study of Resina Draconis on Myocardial Ischemia Rats Using Ultraperformance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry Combined with Pattern Recognition Methods and Metabolic Pathway Analysis

    Directory of Open Access Journals (Sweden)

    Yunpeng Qi

    2013-01-01

    Full Text Available Resina draconis (bright red resin isolated from Dracaena cochinchinensis, RD has been clinically used for treatment of myocardial ischemia (MI for many years. However, the mechanisms of its pharmacological action on MI are still poorly understood. This study aimed to characterize the plasma metabolic profiles of MI and investigate the mechanisms of RD on MI using ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry-based metabolomics combined with pattern recognition methods and metabolic pathway analysis. Twenty metabolite markers characterizing metabolic profile of MI were revealed, which were mainly involved in aminoacyl-tRNA biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis, vascular smooth muscle contraction, sphingolipid metabolism, and so forth. After RD treatment, however, levels of seven MI metabolite markers, including phytosphingosine, sphinganine, acetylcarnitine, cGMP, cAMP, L-tyrosine, and L-valine, were turned over, indicating that RD is likely to alleviate MI through regulating the disturbed vascular smooth muscle contraction, sphingolipid metabolism, phenylalanine metabolism, and BCAA metabolism. To our best knowledge, this is the first comprehensive study to investigate the mechanisms of RD for treating MI, from a metabolomics point of view. Our findings are very valuable to gain a better understanding of MI metabolic profiles and provide novel insights for exploring the mechanisms of RD on MI.

  19. Metabolomics Study of Resina Draconis on Myocardial Ischemia Rats Using Ultraperformance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry Combined with Pattern Recognition Methods and Metabolic Pathway Analysis.

    Science.gov (United States)

    Qi, Yunpeng; Gu, Haiwei; Song, Yunlong; Dong, Xin; Liu, Aijun; Lou, Ziyang; Fan, Guorong; Chai, Yifeng

    2013-01-01

    Resina draconis (bright red resin isolated from Dracaena cochinchinensis, RD) has been clinically used for treatment of myocardial ischemia (MI) for many years. However, the mechanisms of its pharmacological action on MI are still poorly understood. This study aimed to characterize the plasma metabolic profiles of MI and investigate the mechanisms of RD on MI using ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry-based metabolomics combined with pattern recognition methods and metabolic pathway analysis. Twenty metabolite markers characterizing metabolic profile of MI were revealed, which were mainly involved in aminoacyl-tRNA biosynthesis, phenylalanine, tyrosine, and tryptophan biosynthesis, vascular smooth muscle contraction, sphingolipid metabolism, and so forth. After RD treatment, however, levels of seven MI metabolite markers, including phytosphingosine, sphinganine, acetylcarnitine, cGMP, cAMP, L-tyrosine, and L-valine, were turned over, indicating that RD is likely to alleviate MI through regulating the disturbed vascular smooth muscle contraction, sphingolipid metabolism, phenylalanine metabolism, and BCAA metabolism. To our best knowledge, this is the first comprehensive study to investigate the mechanisms of RD for treating MI, from a metabolomics point of view. Our findings are very valuable to gain a better understanding of MI metabolic profiles and provide novel insights for exploring the mechanisms of RD on MI.

  20. Thin Time-Of-Flight PET project

    CERN Multimedia

    The pre-R&D aims at designing and producing a compact and thin Time-Of-Flight PET detector device with depth of interaction measurement capability, which employs layered silicon sensors as active material, with a readout consisting of a new generation of very-low noise and very fast electronics based on SiGe Heterojunction Bipolar Transistors (HBT) components.

  1. ALICE Time of Flight Construction of MRPCs

    CERN Multimedia

    2003-01-01

    Particles are identified in ALICE by time-of-flight (TOF); heavier particles are slower and it takes for them longer to reach the outer layers of the detector. For TOF system ALICE uses detectors called multigap resistive plate chambers, like the prototype shown here.

  2. Design of combined magnetic field system for magnetic-bottle time-of-flight spectrometer%磁瓶飞行时间谱仪用复合磁场系统设计

    Institute of Scientific and Technical Information of China (English)

    王超; 田进寿; 张美志; 康轶凡

    2011-01-01

    根据磁瓶飞行时间谱仪磁场系统的基本要求,设计了一套符合其使用的复合磁场系统.最高强度达1.2T的强非均匀磁场部分由永久磁铁和结构经过优化的截圆锥状磁极靴所产生.永久磁铁为N52系列NdFeB,磁极靴材料为高磁导率珀明德合金.强度为1.0×10-3 T的弱均匀引导磁场由半径为3 cm、长度为3m螺线管提供.磁极靴与螺线管之间的距离为5 cm.%Based on the primary requirement for the magnetic field system in magnetic-bottle time-of-flight spectrometer, an appropriate combined inhomogeneous magnetic field system is designed. The inhomogeneous higher magnetic field part, with the highest field of 1. 2 T. is produced by the combination of a permanent magnet and a pole piece with optimized shape. The magnet, known as NdFeB magnet, is one of rare earth permanent magnets in N52. The guiding uniform magnetic field of 1. 0× 10-3 T is provided by solenoid, with length of 3 m and radius of 3 cm. The pitch between the pole piece and the near end of used solenoid is determined to be 5 cm, which can satisfy the actual engineering needs.

  3. Cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry for screening bioactive capilliposide C metabolites generated by rat intestinal microflora.

    Science.gov (United States)

    Cheng, Zhongzhe; Huang, Meilin; Chen, Guiying; Yang, Guangjie; Zhou, Xin; Chen, Chang; Zhang, Yang; Xu, Yong; Feng, Yulin; Zhang, Lin; Jiang, Hongliang

    2016-02-01

    Many plant-derived glycosides are used as medications. It is common that these glycosides show poor intestinal absorption but their metabolites generated by intestinal microflora demonstrate strong bioactivity. Hence, it is crucial to develop a method for the identification and characterization of the metabolites, and consequently reveal the pathway in which the glycosides are processed in gut. In this study, cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) were developed for rapid discovery and evaluation of the metabolites of a glycoside compound, capilliposide C (LC-C). 92.7% of LC-C was biotransformed by rat intestinal microflora after 36-h incubation at 37°C. Human cancer cell lines HepG2, PC-3 and A549 was treated with metabolites pool, respectively, which was followed by cell viability assays and characterization of metabolites using UHPLC-QTOF-MS/MS. As a result, significant cytotoxicity was observed for the metabolites pool, from which six metabolites were identified. Based on the metabolites identified, deglycosylation and esterolysis were proposed as the major metabolic pathways of LC-C in rat intestinal microflora. In addition, M4, an esterolysis product of LC-C, was obtained and evaluated for its bioactivity in vitro. As a result, M4 exhibited a reduction in cell viability in HepG2 with an IC50 value of 17.46±1.55μg/mL.

  4. Metabolism of cyadox by the intestinal mucosa microsomes and gut flora of swine, and identification of metabolites by high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry.

    Science.gov (United States)

    Xu, Ning; Huang, Lingli; Liu, Zhenli; Pan, Yuanhu; Wang, Xu; Tao, Yanfei; Chen, Dongmei; Wang, Yulian; Peng, Dapeng; Yuan, Zong hui

    2011-08-30

    Cyadox (CYX), 2-formylquinoxaline-1,4-dioxide cyanoacetylhydrazone, is an antimicrobial and growth-promoting feed additive for food-producing animals. To reveal biotransformation of CYX in swine intestine, CYX was incubated with swine intestinal microsomes and mucosa in the presence of an NADPH-generating system and swine ileal flora and colonic flora, respectively. The metabolites of CYX were identified using high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF). Structural elucidation of the metabolites was precisely performed by comparing their changes in molecular mass, full scan MS/MS spectra and accurate mass measurements with those of the parent drug. Finally, seven metabolites were identified as follows: three reduced metabolites (cyadox 1-monoxide (Cy1), cyadox 4-monoxide (Cy2) and bisdesoxycyadox (Cy4)); hydroxylation metabolite (3-hydroxylcyadox 1-monoxide (Cy3)); hydrolysis metabolite of the amide bond (N-decyanoacetyl cyadox (Cy5)); a hydrogenation metabolite (11,12-dihydro-bisdesoxycyadox (Cy6)) and a side-chain cleavage metabolite (2-hydromethylquinoxaline (Cy7)). Only one metabolite (Cy1) was found in intestinal microsomes. Cy1, Cy2 and Cy4 were detected in intestinal mucosa, ileal and colonic flora. In addition, Cy3 and Cy5 were only obtained from ileal flora, and Cy6 and Cy7 alone were observed in colonic bacteria. The results indicated that N→O group reduction was the main metabolic pathway of CYX metabolism in swine ileal flora, intestinal microsomes and mucosa. New metabolic profiles of hydrogenation and cleavage on the side chain were found in colonic bacteria. Among the identified metabolites, two new metabolites (Cy6, Cy7) were detected for the first time. These studies will contribute to clarify comprehensively the metabolism of CYX in animals, and provide evidence to explain the pharmacology and toxicology effects of CYX in animals.

  5. Identification of regioisomers of methylated kaempferol and quercetin by ultra high performance liquid chromatography quadrupole time-of-flight (UHPLC–QTOF) tandem mass spectrometry combined with diagnostic fragmentation pattern analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Chengying; Lv, Haipeng; Zhang, Xinzhong; Chen, Zongmao; Shi, Jiang [Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 Meiling South Road, Hangzhou, Zhejiang 310008 (China); Lu, Meiling, E-mail: meilinglu@hotmail.com [Chemical Analysis Group, Agilent Technologies, No. 3 Wangjing North Road, Chaoyang Distr., Beijing 100102 (China); Lin, Zhi, E-mail: linz@mail.tricaas.com [Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 Meiling South Road, Hangzhou, Zhejiang 310008 (China)

    2013-09-17

    Highlights: •Found methane elimination is position-specific for methylated flavonols. •Found retro Diels–Alder fragments retained methoxy at original ring of flavonols. •Proposed a diagnostic pattern for discriminating regioisomers of flavonols. •Identified the specificity of three novel flavonol O-methyltransferases. •Identified six biologically active compounds and four new compounds. -- Abstract: The O-methylation of active flavonoids can enhance their antiallergic, anticancerous, and cardioprotective effects depending on the methylation position. Thus, it is biologically and pharmacologically important to differentiate methylated flavonoid regioisomers. In this study, we examined the regioisomers of methylated kaempferol and quercetin using ultra high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry. The methyl groups on the flavonoids can generally be cleaved as methyl radicals in a position-independent manner. We found that methyl groups can be cleaved as methane. If there are protons adjacent the methoxy on the flavonol rings, intra-molecule proton transfer can occur via collision-induced dissociation, and one molecule of methane can then be eliminated. The remaining charged fragment ([M+H−CH{sub 4}]{sup +}) reflects the adjacent structure and is specific to the methoxy position. Furthermore, the retro Diels–Alder (RDA) fragmentation of methylated flavonols can generate fragments with the methoxy at the original methylated ring. Combining the position-specific [M+H−CH{sub 4}]{sup +} fragment with the RDA fragments provides a diagnostic pattern for rapidly identifying methylated regioisomeric flavonols. Along with their retention behaviour, we have successfully identified ten regioisomers of methylated kaempferol and quercetin, which include six compounds previously reported in plants and shown to be biologically active. The developed approach is sensitive, rapid, reliable, and requires few standard

  6. The CDF Time of Flight Detector

    Energy Technology Data Exchange (ETDEWEB)

    S. Cabrera et al.

    2004-01-06

    A new Time of Flight (TOF) detector based on scintillator bars with fine-mesh photomultipliers at both ends has been in operation since 2001 in the CDF experiment. With a design resolution of 100 ps, the TOF can provide separation between K{sup +-} and {pi}{sup +-} in p{bar p} collisions at the 2{omega} level for low momentum, which enhances b flavor tagging capabilities. Because of its very fast response, the TOF is an excellent triggering device, and it is used to trigger on highly ionizing particles, multiple minimum ionizing particles and cosmic rays. Particle identification is achieved by comparing the time-of-flight of the particle measured by the TOF to the time expected for a given mass hypothesis. In order to obtain the resolution necessary for particle ID, optimal calibrations are critical. This paper describes the TOF detector, its calibration procedure, the achieved resolution, the long term operation performances and some of the first results from data analysis using this detector.

  7. Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).

    Science.gov (United States)

    Idelevich, Evgeny A; Grünastel, Barbara; Becker, Karsten

    2017-01-01

    Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. Copyright © 2016 American Society for Microbiology.

  8. Time-of-flight cameras principles, methods and applications

    CERN Document Server

    Hansard, Miles; Choi, Ouk; Horaud, Radu

    2012-01-01

    Time-of-flight (TOF) cameras provide a depth value at each pixel, from which the 3D structure of the scene can be estimated. This new type of active sensor makes it possible to go beyond traditional 2D image processing, directly to depth-based and 3D scene processing. Many computer vision and graphics applications can benefit from TOF data, including 3D reconstruction, activity and gesture recognition, motion capture and face detection. It is already possible to use multiple TOF cameras, in order to increase the scene coverage, and to combine the depth data with images from several colour came

  9. Doppler time-of-flight imaging

    KAUST Repository

    Heidrich, Wolfgang

    2017-02-16

    Systems and methods for imaging object velocity are provided. In an embodiment, at least one Time-of-Flight camera is used to capture a signal representative of an object in motion over an exposure time. Illumination and modulation frequency of the captured motion are coded within the exposure time. A change of illumination frequency is mapped to measured pixel intensities of the captured motion within the exposure time, and information about a Doppler shift in the illumination frequency is extracted to obtain a measurement of instantaneous per pixel velocity of the object in motion. The radial velocity information of the object in motion can be simultaneously captured for each pixel captured within the exposure time. In one or more aspects, the illumination frequency can be coded orthogonal to the modulation frequency of the captured motion. The change of illumination frequency can correspond to radial object velocity.

  10. Miniaturised Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Rohner, U.; Benz, W.; Whitby, J. A.; Wurz, P.; Schulz, R.; Romstedt, J.

    2004-04-01

    Originally intended for the European Space Agency's BepiColombo mission to Mercury, we have built a series of highly miniaturised laser ablation time of flight mass spectrometers (LMS), suitable for in situ measurements of the elemental and isotopic composition of the surface of airless planetary bodies. The instruments will determine ma jor, minor, and trace element abundances in minerals on a spatial scale of 10 m, and will have sufficient dynamic range and mass resolution to perform useful isotopic measurements in favourable cases. Solid material is simultaneously evaporated and ionised by means of laser ablation, requiring intense pulsed laser radiation. Laser ablation was chosen as the sample introduction technique principally because of its high spatial resolution and the lack of any need for sample preparation. Advantages of the technique include simplicity of the resulting design, speed of measurement, and the ability for depth profiling (potentially important for a regolith in which mineral grains are coated with impact produced glass). Time of flight mass spectrometers are simple, robust devices that couple well to a pulsed ion source and we have previous experience of their construction for space flight, e.g. the ROSINA instrument suite for the ROSETTA mission. For BepiColombo, we have built two prototype instruments, one with a design mass of 500 g and a volume comparable to a beer can intended to be deployed on a static lander, and a smaller cigarettebox sized version with a design mass of 250 g, small enough to be integrated in a rover or robotic arm.

  11. TITAN's multiple-reflection time-of-flight isobar separator

    Science.gov (United States)

    Reiter, Moritz Pascal; Titan Collaboration

    2016-09-01

    At the ISAC facility located at TRIUMF exotic nuclei are produced by the ISOL method. Exotic nuclei are separated by a magnetic separator and transported to TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). TITAN is a system of multiple ion traps for high precision mass measurements and in-trap decay spectroscopy. Although ISAC can deliver some of the highest yields for even many of the most exotic species many measurements suffer from a strong isobaric background. This background often prevents the high precision measurement of the species of interest. To overcome this limitation an additional isobar separator based on the Multiple-Reflection Time-Of-Flight Mass Spectrometry (MR-TOF-MS) technique has been developed for TITAN. Mass selection is achieved using dynamic re-trapping of the species of interest after a time-of-flight analysis in an electrostatic isochronous reflector system. Additionally the MR-TOF-MS will, on its own, enable mass measurements of very short-lived nuclides that are weakly produced. Being able to measure all isobars of a given mass number at the same time the MR-TOF-MS can be used for beam diagnostics or determination of beam compositions. Results from the offline commissioning showing mass resolving power and separation power will be presented.

  12. The ALICE Time of Flight Readout System AFRO

    CERN Document Server

    Kluge, A

    1999-01-01

    The ALICE Time of Flight Detector system comprises more than 100.000 channels and covers an area of more than 100 m2. The timing resolution should be better than 150 ps. This combination of requirements poses a major challenge to the readout system. All detector timing measurements are referenced to a unique start signal t0. This signal is generated at the time an event occurs. Timing measurements are performed using a multichannel TDC chip which requires a 40 MHz reference clock signal. The general concept of the readout system is based on a modular architecture. Detector cells are combined to modules of 1024 channels. Each of these modules can be read out and calibrated independently from each other. By distributing a reference signal, a timing relationship between the modules is established. This reference signal can either be the start signal t0 or the TDC-reference clock. The readout architecture is divided into three steps; the TDC controller, the module controller, and the time of flight controller. Th...

  13. Qualitative and quantitative analysis of the chemical constituents in Mahuang-Fuzi-Xixin decoction based on high performance liquid chromatography combined with time-of-flight mass spectrometry and triple quadrupole mass spectrometers.

    Science.gov (United States)

    Sun, Qihui; Cao, Hongjie; Zhou, Yanyan; Wang, Xu; Jiang, Haiqiang; Gong, Lili; Yang, Yong; Rong, Rong

    2016-11-01

    High-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF/MS) and high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-QQQ/MS/MS) were utilized to clarify the chemical constituents of Mahuang-Fuzi-Xixin Decoction. There are 52 compounds, including alkaloids, amino acids and organic acids were identified or tentatively characterized by their characteristic high resolution mass data by HPLC-QQQ/MS/MS. In the subsequent quantitative analysis, 10 constituents, including methyl ephedrine, aconine, songrine, fuziline, neoline, talatisamine, chasmanine, benzoylmesaconine, benzoylaconine and benzoylhypaconine were simultaneously determined by HPLC-QQQ/MS/MS with multiple reaction monitoring mode. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.9992). The relative standard deviations (RSD) of inter- and intra-day precisions were chemical constituents studying, including identification and quantification of Mahuang-Fuzi-Xixin decoction. Copyright © 2016 John Wiley & Sons, Ltd.

  14. A purge and trap technique to capture volatile compounds combined with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry to investigate the effect of sulfur-fumigation on Radix Angelicae Dahuricae.

    Science.gov (United States)

    Cao, Gang; Li, Qinglin; Zhang, Jida; Cai, Hao; Cai, Baochang

    2014-09-01

    Sulfur-fumigation is known to reduce volatile compounds that are the main active components in herbs used in herbal medicine. We investigated changes in chemical composition between sun-dried and sulfur-fumigated Radix Angelicae Dahuricae using a purge and trap technique to capture volatile compounds, and two-dimensional gas chromatography/time-of-flight mass spectrometry for identification. Using sun-dried Radix Angelicae Dahuricae samples as a reference, the results showed that 73 volatile compounds, including 12 sulfide compounds, were found to be present only in sulfur-fumigated samples. Furthermore, 32 volatile compounds that were found in sun-dried Radix Angelicae Dahuricae samples disappeared after sulfur-fumigation. The proposed method can be applied to accurately discriminate sulfur-fumigated Radix Angelicae Dahuricae from different commercial sources.

  15. Network generation enhances interpretation of proteomics data sets by a combination of two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Wang, Xijun; Zhang, Aihua; Sun, Hui; Wu, Gelin; Sun, Wenjun; Yan, Guangli

    2012-10-21

    Recent advances in proteomic technologies have enabled us to create detailed protein-protein interaction maps in diseases. As the size of the interaction dataset increases, powerful computational methods are required in order to effectively interpret network models from large scale interactome data. In this study, we carried out comparative proteomics to construct and identify the proteins networks associated with hepatic injury (HI) which are largely unknown, as a case study. All proteins expressed were separated and identified by two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight-time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Protein-interacting networks and pathways were mapped using STRING analysis program. We have performed for the first time a comprehensive profiling of changes in protein expression of HI rats, to uncover the networks altered by treated with CCl(4). Identification of fifteen spots (seven over-expressed and eight under-expressed) were established by MALDI-TOF/TOF MS. These proteins were subjected to functional pathway analysis using STRING software for better understanding of the biological context of the identified proteins. It suggested that modulation of multiple vital physiological pathways including DNA repair process, cell apoptosis, oxidation reduction, signal transduction, metabolic process, intracellular signaling cascade, regulation of biological processes, cell communication, regulation of cellular process, and molecular transport. In summary, the present study provides the first protein-interacting network maps and novel insights into the biological responses and potential pathways of HI. The generation of protein interaction networks clearly enhances the interpretation of proteomic data, particularly in respect of understanding molecular mechanisms of panel protein biomarkers.

  16. Advances in time-of-flight PET.

    Science.gov (United States)

    Surti, Suleman; Karp, Joel S

    2016-01-01

    This paper provides a review and an update on time-of-flight PET imaging with a focus on PET instrumentation, ranging from hardware design to software algorithms. We first present a short introduction to PET, followed by a description of TOF PET imaging and its history from the early days. Next, we introduce the current state-of-art in TOF PET technology and briefly summarize the benefits of TOF PET imaging. This is followed by a discussion of the various technological advancements in hardware (scintillators, photo-sensors, electronics) and software (image reconstruction) that have led to the current widespread use of TOF PET technology, and future developments that have the potential for further improvements in the TOF imaging performance. We conclude with a discussion of some new research areas that have opened up in PET imaging as a result of having good system timing resolution, ranging from new algorithms for attenuation correction, through efficient system calibration techniques, to potential for new PET system designs.

  17. Advances in time-of-flight PET

    Science.gov (United States)

    Surti, Suleman; Karp, Joel S.

    2016-01-01

    This paper provides a review and an update on time-of-flight PET imaging with a focus on PET instrumentation, ranging from hardware design to software algorithms. We first present a short introduction to PET, followed by a description of TOF PET imaging and its history from the early days. Next, we introduce the current state-of-art in TOF PET technology and briefly summarize the benefits of TOF PET imaging. This is followed by a discussion of the various technological advancements in hardware (scintillators, photo-sensors, electronics) and software (image reconstruction) that have led to the current widespread use of TOF PET technology, and future developments that have the potential for further improvements in the TOF imaging performance. We conclude with a discussion of some new research areas that have opened up in PET imaging as a result of having good system timing resolution, ranging from new algorithms for attenuation correction, through efficient system calibration techniques, to potential for new PET system designs. PMID:26778577

  18. Wide-scope screening and quantification of 50 pesticides in wine by liquid chromatography/quadrupole time-of-flight mass spectrometry combined with liquid chromatography/quadrupole linear ion trap mass spectrometry.

    Science.gov (United States)

    He, Zeying; Xu, Yaping; Wang, Lu; Peng, Yi; Luo, Ming; Cheng, Haiyan; Liu, Xiaowei

    2016-04-01

    In this paper, a wide scope screening method of pesticides in wine was established using liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF MS) and liquid chromatography/quadrupole linear ion trap mass spectrometry (LC-QqLIT MS). Information dependent acquisition (IDA) experiments are used to obtain both MS and MS/MS information for LC-QTOF MS analysis. For LC-QqLIT MS analysis, MS/MS spectra of target pesticides were simultaneously acquired using Enhanced Product Ion (EPI) mode at very low concentrations to increase the confidence in analytical results of multiple reaction monitoring (MRM) by library searching. Method validation was carried out using 50 pesticides commonly used in vineyards. The LOQs, linearity, repeatability were determined and good enough for quantification. The screening and quantification results obtained using LC-QTOF MS and LC-QqLIT MS were compared. Contaminants were screened against libraries containing over 2800 compounds based on accurate mass, isotopic patterns, and MS/MS spectra searching to extend the scope of this methodology to non-target screening.

  19. Fingerprint analysis and quality consistency evaluation of flavonoid compounds for fermented Guava leaf by combining high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry and chemometric methods.

    Science.gov (United States)

    Wang, Lu; Tian, Xiaofei; Wei, Wenhao; Chen, Gong; Wu, Zhenqiang

    2016-10-01

    Guava leaves are used in traditional herbal teas as antidiabetic therapies. Flavonoids are the main active of Guava leaves and have many physiological functions. However, the flavonoid compositions and activities of Guava leaves could change due to microbial fermentation. A high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry method was applied to identify the varieties of the flavonoids in Guava leaves before and after fermentation. High-performance liquid chromatography, hierarchical cluster analysis and principal component analysis were used to quantitatively determine the changes in flavonoid compositions and evaluate the consistency and quality of Guava leaves. Monascus anka Saccharomyces cerevisiae fermented Guava leaves contained 2.32- and 4.06-fold more total flavonoids and quercetin, respectively, than natural Guava leaves. The flavonoid compounds of the natural Guava leaves had similarities ranging from 0.837 to 0.927. The flavonoid compounds from the Monascus anka S. cerevisiae fermented Guava leaves had similarities higher than 0.993. This indicated that the quality consistency of the fermented Guava leaves was better than that of the natural Guava leaves. High-performance liquid chromatography fingerprinting and chemometric analysis are promising methods for evaluating the degree of fermentation of Guava leaves based on quality consistency, which could be used in assessing flavonoid compounds for the production of fermented Guava leaves.

  20. Novel Solid-State Devices as Timing Detectors for Ion Time-of-Flight Measurements

    Science.gov (United States)

    Ogasawara, K.; Allegrini, F.; Desai, M. I.; Livi, S. A.

    2016-10-01

    This study reports on the performance of Avalanche Photodiode (APD) and Multi-Pixel Photon Counter (MPPC) as timing detectors for ion time-of-flight mass spectroscopy. APDs detect >10 keV ions directly, while MPPCs detect sub-keV secondary electrons.

  1. VCSELs as light source for time-of-flight sensors

    Science.gov (United States)

    Moench, Holger; Frey, Manuel; Grabherr, Martin; Gronenborn, Stephan; Gudde, Ralph; Kolb, Johanna; Miller, Michael; Weigl, Alexander

    2017-02-01

    VCSELs and VCSEL arrays are an ideal light source for time-of-flight based sensors. The narrow emission spectrum and the ability for short pulses make them superior to LEDs. Combined with fast photodiodes or special camera chips spatial 3D information can be obtained which is needed in diverse applications like camera autofocus, indoor navigation, 3Dobject recognition or even autonomously driving vehicles. VCSEL arrays are the way to tailor the output power. For pulse operation at low duty cycle average heat dissipation is no longer the upper limit to the operating point of VCSELs but over-pulsing becomes possible. Taking into account electrical boundary conditions and optimum conversion efficiency arrays can be designed for specific operating conditions. Measurements of arrays under short pulse operation are presented using a package with integrated driver.

  2. Correlation Time-of-flight Spectrometry of Ultracold Neutrons

    CERN Document Server

    Novopoltsev, M I

    2010-01-01

    The fearures of the correlation method used in time-of-flight spectrometry of ultracold neutrons are analyzed. The time-of-flight spectrometer for the energy range of ultracold neutrons is described, and results of its testing by measuring spectra of neutrons passing through interference filters are presented.

  3. A weighted optimization approach to time-of-flight sensor fusion.

    Science.gov (United States)

    Schwarz, Sebastian; Sjostrom, Marten; Olsson, Roger

    2014-01-01

    Acquiring scenery depth is a fundamental task in computer vision, with many applications in manufacturing, surveillance, or robotics relying on accurate scenery information. Time-of-flight cameras can provide depth information in real-time and overcome short-comings of traditional stereo analysis. However, they provide limited spatial resolution and sophisticated upscaling algorithms are sought after. In this paper, we present a sensor fusion approach to time-of-flight super resolution, based on the combination of depth and texture sources. Unlike other texture guided approaches, we interpret the depth upscaling process as a weighted energy optimization problem. Three different weights are introduced, employing different available sensor data. The individual weights address object boundaries in depth, depth sensor noise, and temporal consistency. Applied in consecutive order, they form three weighting strategies for time-of-flight super resolution. Objective evaluations show advantages in depth accuracy and for depth image based rendering compared with state-of-the-art depth upscaling. Subjective view synthesis evaluation shows a significant increase in viewer preference by a factor of four in stereoscopic viewing conditions. To the best of our knowledge, this is the first extensive subjective test performed on time-of-flight depth upscaling. Objective and subjective results proof the suitability of our approach to time-of-flight super resolution approach for depth scenery capture.

  4. Potential advantages of a cesium fluoride scintillator for a time-of-flight positron camera.

    Science.gov (United States)

    Allemand, R; Gresset, C; Vacher, J

    1980-02-01

    In order to improve the quality of positron tomographic imaging, a time-of-flight technique combined with a classical reconstruction method has been investigated. The decay time of NaI(Tl) and bismuth germanate (BGO) scintillators is too long for this application, and efficiency of the plastic scintillators is too low. Cesium fluoride appears to be a very promising detector material. This paper presents preliminary results obtained with a time-of-flight technique using CsF scintillators. The expected advantages were realized.

  5. Pd/Pt(1 1 1) surface structure and metal epitaxy by time-of-flight impact-collision ion scattering spectroscopy and scanning tunneling microscopy: Does lattice mismatch really determine the growth mode?

    Science.gov (United States)

    Umezawa, K.; Narihiro, E.; Ohta, Y.; Ohira, Y.; Yoshimura, M.

    2008-04-01

    We have investigated the growth of 3 ML of Pd on Pt(1 1 1) at substrate temperature of around 300 K using TOF-ICISS. Also a series of STM topographs were taken as a function of coverage of Pd atoms. The Pd-Pt(1 1 1) combination does not have lattice mismatch (less than 1%); the nearest neighbor distance of bulk Pd(1 1 1) and Pt(1 1 1) are 2.75 Å and 2.77 Å, respectively. Experimental data and computer simulations result clearly show the growth mode of Pd(1 1 1) [ 2 bar 1 1]/Pt(1 1 1) [ 2 bar 1 1] hetero epitaxy at the coverage of the Pd deposition less than 3 ML. The growth mode of Pd(1 1 1) [ 1 bar 1 bar 2 ]/Pt(1 1 1) [ 2 bar 1 1] could not be observed at all. One would expect that the growth mode of Pd atoms on Pt(1 1 1) surfaces is like homo epitaxy (layer-by-layer growth), because of no lattice mismatch (less than 1%). However, it was not. The calculated surface and interface energies and STM results show 2D or 3D dimensional island growth. Pd atoms is mainly form dense islands at the steps on Pt(1 1 1) surfaces at the coverage of 0.13 ML.

  6. Experimental investigation on ionized ultracold molecules formed in a magneto-optical trap by time-of-flight mass spectroscopy%飞行时问质谱探测磁光阱中超冷分子离子的实验研究

    Institute of Scientific and Technical Information of China (English)

    元晋鹏; 姬中华; 杨艳; 张洪山; 赵延霆; 马杰; 汪丽蓉; 肖连团; 贾锁堂

    2012-01-01

    We use time-of-flight mass spectroscopy to detect the ultracold ground state Cs2 molecules formed directly by a photoassociation due to the trapping laser beams and repumping laser beam in a magneto-optical trap. We investigate the dependences of the Cs+ intensity on operating voltage of micro-channel-plate, accelerating field intensity and duration time of the accelerating field. The experimental results are consistent with theoretical fitting. We obtain the best optimal parameters suited to our experimental condition, which is important for the future experiment on ultracold molecule photoassociation and photoionization spectroscopy.%利用飞行时间质谱探测了由磁光阱中的俘获光和再泵浦光光缔合作用形成的超冷基态铯分子,研究了微通道板工作电压、加速电场强度和加速电场持续时间对铯分子离子信号强度的影响.实验结果与理论模型的拟合一致;获得了适合实验条件的最优化实验参数,为进一步研究超冷分子的光缔合光谱和光电离光谱奠定了实验基础.

  7. Time-of-Flight Effects in Microwave Transmission Through a Thin Metal Slab

    DEFF Research Database (Denmark)

    Henningsen, J. O.; Falk, David S.

    1971-01-01

    A 45-GHz size-effect experiment on Ag revealed significant structure in the combined transmission and leakage signal below the first-belly-electron size effects. The oscillations, which behave differently for different field orientations, are shown to be due to the time-of-flight phase delay of e...

  8. Estimating time and time-lag in time-of-flight velocimetry

    Science.gov (United States)

    Lading, L.

    1983-01-01

    Estimating time and time-lag in time-of-flight velocimeters is investigated. Statistics of a filtered Poisson point process is given. A Maximum Likelihood Estimator is compared with suboptimum estimators in terms of robustness. For a dominating background combined spatial and temporal processing can improve the robustness compared with purely temporal processing. Schemes for the spatial filters are given.

  9. FOCUS: neutron time-of-flight spectrometer at SINQ: recent progress

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, S.; Mesot, J.; Holitzner, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Hempelmann, R. [Saarbruecken Univ. (Germany)

    1997-09-01

    At the Swiss neutron spallation source SINQ a time-of-flight spectrometer for cold neutrons is under construction. The design foresees a Hybrid solution combining a Fermi chopper with a doubly focusing crystal monochromator. During 1996 important progress has been made concerning the main spectrometer components such as the spectrometer housing and the detector system. (author) 2 figs., 3 refs.

  10. Nano-localized desorption and time-of-flight mass analysis using solely optical enhancement in the proximity of a scanning tunneling microscope tip

    Science.gov (United States)

    Ding, Yu; Micheletto, Ruggero; Okazaki, Satoshi; Otsuka, Koji

    2003-04-01

    The combination of scanning tunneling microscopy (STM) with time-of-flight mass system (TOF-MS) adds new information to STM imaging. In this study, an STM system has been combined with laser excitation and was used for desorption and ionization of surface molecules, without the use of any other external stimulus. Desorbed ions from confined areas were accelerated and detected by a TOF chamber. We demonstrate in this paper that the technique proposed enables desorption of superficial structures within a small area of approximately 5 nm diameter and simultaneous mass spectroscopy of the desorbed atoms.

  11. Performance of the Tachyon Time-of-Flight PET Camera.

    Science.gov (United States)

    Peng, Q; Choong, W-S; Vu, C; Huber, J S; Janecek, M; Wilson, D; Huesman, R H; Qi, Jinyi; Zhou, Jian; Moses, W W

    2015-02-01

    We have constructed and characterized a time-of-flight Positron Emission Tomography (TOF PET) camera called the Tachyon. The Tachyon is a single-ring Lutetium Oxyorthosilicate (LSO) based camera designed to obtain significantly better timing resolution than the ~ 550 ps found in present commercial TOF cameras, in order to quantify the benefit of improved TOF resolution for clinically relevant tasks. The Tachyon's detector module is optimized for timing by coupling the 6.15 × 25 mm(2) side of 6.15 × 6.15 × 25 mm(3) LSO scintillator crystals onto a 1-inch diameter Hamamatsu R-9800 PMT with a super-bialkali photocathode. We characterized the camera according to the NEMA NU 2-2012 standard, measuring the energy resolution, timing resolution, spatial resolution, noise equivalent count rates and sensitivity. The Tachyon achieved a coincidence timing resolution of 314 ps +/- ps FWHM over all crystal-crystal combinations. Experiments were performed with the NEMA body phantom to assess the imaging performance improvement over non-TOF PET. The results show that at a matched contrast, incorporating 314 ps TOF reduces the standard deviation of the contrast by a factor of about 2.3.

  12. Structure determination of two conotoxins from Conus textile by a combination of matrix-assisted laser desorption/ionization time-of-flight and electrospray ionization mass spectrometry and biochemical methods

    DEFF Research Database (Denmark)

    Kalume, D E; Stenflo, J; Czerwiec, E

    2000-01-01

    Two highly modified conotoxins from the mollusc Conus textile, epsilon-TxIX and Gla(1)-TxVI, were characterized by matrix-assisted laser desorption/ionization and electrospray mass spectrometry and also by electrospray ionization tandem and triple mass spectrometry in combination with enzymatic c...... esterification was found necessary for the site-specific assignment of the Gla residues in the peptides....

  13. Chemical characterization of latent fingerprints by matrix-assisted laser desorption ionization, time-of-flight secondary ion mass spectrometry, mega electron volt secondary mass spectrometry, gas chromatography/mass spectrometry, X-ray photoelectron spectroscopy, and attenuated total reflection Fourier transform infrared spectroscopic imaging: an intercomparison.

    Science.gov (United States)

    Bailey, Melanie J; Bright, Nicholas J; Croxton, Ruth S; Francese, Simona; Ferguson, Leesa S; Hinder, Stephen; Jickells, Sue; Jones, Benjamin J; Jones, Brian N; Kazarian, Sergei G; Ojeda, Jesus J; Webb, Roger P; Wolstenholme, Rosalind; Bleay, Stephen

    2012-10-16

    The first analytical intercomparison of fingerprint residue using equivalent samples of latent fingerprint residue and characterized by a suite of relevant techniques is presented. This work has never been undertaken, presumably due to the perishable nature of fingerprint residue, the lack of fingerprint standards, and the intradonor variability, which impacts sample reproducibility. For the first time, time-of-flight secondary ion mass spectrometry, high-energy secondary ion mass spectrometry, and X-ray photoelectron spectroscopy are used to target endogenous compounds in fingerprints and a method is presented for establishing their relative abundance in fingerprint residue. Comparison of the newer techniques with the more established gas chromatography/mass spectrometry and attenuated total reflection Fourier transform infrared spectroscopic imaging shows good agreement between the methods, with each method detecting repeatable differences between the donors, with the exception of matrix-assisted laser desorption ionization, for which quantitative analysis has not yet been established. We further comment on the sensitivity, selectivity, and practicability of each of the methods for use in future police casework or academic research.

  14. Metabolite identification of seven active components of Huan-Nao-Yi-Cong-Fang in rat plasma using high-performance liquid chromatography combined with hybrid ion trap/time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Minchao; Lu, Yanzhen; Liu, Jiangang; Li, Hao; Wei, Yun

    2016-02-01

    Huan-Nao-Yi-Cong-Fang (HNYCF) is a potential prescription in treating Alzheimer's disease. Seven constituents [ferulic acid (FA), 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside (THSG), berberine hydrochloride (BHCl), emodin, ginsenoside Rg1 (Rg1), ginsenoside Re (Re) and ginsenoside Rb1 (Rb1)] have been used as quality chemical markers of HNYCF owing to their biological significance and high contents in crude plant materials. This study explored the metabolites of the seven bioactive components in rat plasma to give useful data for further study of the action mechanism of HNYCF. LC/MS-IT-TOF was used to simultaneously characterize the metabolites of the seven components. Using the combination of MetID Solution 1.0 software and accurate mass measurements, the metabolites of HNYCF were reliably characterized. Their structures were elucidated based on the accurate MS(2) spectra and comparisons of their changes in accurate molecular masses and fragment ions with those of parent compounds. A total of five parent active compounds (BHCl, emodin, Rg1, Rb1 and Re) and 10 metabolites were found from the rat plasma 2 h after oral administration of HNYCF dosage, of which two metabolites of emodin were observed for the first time. The proposed metabolic pathways of the bioactive components in the rat plasma are helpful for further studies on the pharmacokinetics and real active compound forms of this drug.

  15. Sensomics analysis of key hazelnut odorants (Corylus avellana L. 'Tonda Gentile') using comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC×GC-TOF-MS).

    Science.gov (United States)

    Kiefl, Johannes; Pollner, Gwendola; Schieberle, Peter

    2013-06-05

    Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) has been used a few times to identify and quantitate single aroma-active compounds, but the capability of this technique to monitor a complete set of key odorants evoking the aroma of a given food in one run has not been exploited so far. A fast, multiodorant analysis using GC×GC-TOF-MS in combination with stable isotope dilution assays (SIDA) was developed to quantitate the entire set of aroma compounds, the sensometabolome, of raw and roasted hazelnuts ( Corylus avellana L. 'Tonda Gentile') previously established by GC-olfactometry. The capability of the method to evaluate the aroma contribution of each sensometabolite was evaluated by introducing a new term, the limit of odor activity value (LOAV), indicating whether a given aroma compound can be determined down to an odor activity value (OAV) of 1 (odor activity value = ratio of concentration to odor threshold). The advantage of the new method was proven by comparing the performance parameters with a traditional one-dimensional approach using GC-ion trap mass-spectrometry (GC-IT-MS). The results showed that the detector linearity and sensitivity of GC×GC-TOF-MS was on average higher by a factor of 10 compared to GC-IT-MS, thus enabling the quantitation of the aroma relevant amounts of 22 key odorants of hazelnuts in one run of the 30 aroma-active compounds. Seven novel isotopically labeled internal standards were synthesized to meet the analytical requirements defined by electron impact ionization in TOF-MS, that is, to keep the label. On the basis of the quantitative results obtained, it was possible to closely mimic the aroma of raw and roasted 'Tonda Gentile' hazelnuts by preparing an aroma recombinate containing the key odorants at their natural concentrations occurring in the nuts.

  16. Time-of-Flight Mass Measurements of Neutron Rich Nuclides

    Science.gov (United States)

    Estrade, A.; Matos, M.; Amthor, A. M.; Becerril, A.; Elliot, T.; Lorusso, G.; Rogers, A.; Schatz, H.; Bazin, D.; Gade, A.; Portillo, M.; Stolz, A.; Galaviz, D.; Pereira, J.; Shapira, D.; Smith, E.; Wallace, M.

    2008-10-01

    Nuclear masses of neutron rich isotopes in the region of Z ˜ 20-30 have been measured using the time-of-flight technique at the National Superconducting Cyclotron Laboratory (NSCL). The masses of 5 isotopes have been measured for the first time, and the precision of several other masses has been improved. The time-of-flight technique has shown the potential to access nuclear masses very far from stability when applied at radioactive beam facilities like the NSCL. Such measurements are important for understanding nuclear structure far from the valley of β-stability, and provide valuable information for astrophysical model calculations of processes involving very unstable nuclides.

  17. HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    SHAPIRO,S.M.ZALIZNYAK,I.PASSELL,L.GHOSH,V.

    2003-05-12

    HYSPEC combines time-of-flight spectroscopy with focusing Bragg optics to enhance the flux on small single crystal samples. It will look at a coupled H{sub 2} moderator and will use a 20-25 meter supermirror guide to transport the neutron beam. A counter-rotating chopper pair will monochromate the beam and determine the neutron burst width. A short distance from the chopper pair a vertical focusing crystal is placed in a drum shield that will focus the beam to a 2 cm height, thus maximizing the flux at the sample position. Collimators and beam definers will be placed before and after the sample, which will allow standard sample environment equipment to be used covering a wide range of temperatures and magnetic fields. About 200 He{sup 3} position sensitive detectors will be housed in a moveable detector bank 4.5 m from the sample to cover a horizontal range of 60{sup o} and a vertical range of {+-}7.5{sup o}. HYSPEC can easily be converted to a polarized beam instrument by using a Heusler crystal for a monochromator, and supermirror benders for polarization analysis of the scattered beam. HYSPEC is a moderate resolution instrument optimized for an incident energy range of 5

  18. Recent developments in time-of-flight PET

    Energy Technology Data Exchange (ETDEWEB)

    Vandenberghe, S.; Mikhaylova, E.; D’Hoe, E.; Mollet, P. [ELIS-IMINDS-Medical IT-IBITECH Ghent University, De Pintelaan 185, Blok B, Gent, 9000 (Belgium); Karp, J. S. [Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2016-02-16

    While the first time-of-flight (TOF)-positron emission tomography (PET) systems were already built in the early 1980s, limited clinical studies were acquired on these scanners. PET was still a research tool, and the available TOF-PET systems were experimental. Due to a combination of low stopping power and limited spatial resolution (caused by limited light output of the scintillators), these systems could not compete with bismuth germanate (BGO)-based PET scanners. Developments on TOF system were limited for about a decade but started again around 2000. The combination of fast photomultipliers, scintillators with high density, modern electronics, and faster computing power for image reconstruction have made it possible to introduce this principle in clinical TOF-PET systems. This paper reviews recent developments in system design, image reconstruction, corrections, and the potential in new applications for TOF-PET. After explaining the basic principles of time-of-flight, the difficulties in detector technology and electronics to obtain a good and stable timing resolution are shortly explained. The available clinical systems and prototypes under development are described in detail. The development of this type of PET scanner also requires modified image reconstruction with accurate modeling and correction methods. The additional dimension introduced by the time difference motivates a shift from sinogram- to listmode-based reconstruction. This reconstruction is however rather slow and therefore rebinning techniques specific for TOF data have been proposed. The main motivation for TOF-PET remains the large potential for image quality improvement and more accurate quantification for a given number of counts. The gain is related to the ratio of object size and spatial extent of the TOF kernel and is therefore particularly relevant for heavy patients, where image quality degrades significantly due to increased attenuation (low counts) and high scatter fractions. The

  19. Recent developments in time-of-flight PET.

    Science.gov (United States)

    Vandenberghe, S; Mikhaylova, E; D'Hoe, E; Mollet, P; Karp, J S

    2016-12-01

    While the first time-of-flight (TOF)-positron emission tomography (PET) systems were already built in the early 1980s, limited clinical studies were acquired on these scanners. PET was still a research tool, and the available TOF-PET systems were experimental. Due to a combination of low stopping power and limited spatial resolution (caused by limited light output of the scintillators), these systems could not compete with bismuth germanate (BGO)-based PET scanners. Developments on TOF system were limited for about a decade but started again around 2000. The combination of fast photomultipliers, scintillators with high density, modern electronics, and faster computing power for image reconstruction have made it possible to introduce this principle in clinical TOF-PET systems. This paper reviews recent developments in system design, image reconstruction, corrections, and the potential in new applications for TOF-PET. After explaining the basic principles of time-of-flight, the difficulties in detector technology and electronics to obtain a good and stable timing resolution are shortly explained. The available clinical systems and prototypes under development are described in detail. The development of this type of PET scanner also requires modified image reconstruction with accurate modeling and correction methods. The additional dimension introduced by the time difference motivates a shift from sinogram- to listmode-based reconstruction. This reconstruction is however rather slow and therefore rebinning techniques specific for TOF data have been proposed. The main motivation for TOF-PET remains the large potential for image quality improvement and more accurate quantification for a given number of counts. The gain is related to the ratio of object size and spatial extent of the TOF kernel and is therefore particularly relevant for heavy patients, where image quality degrades significantly due to increased attenuation (low counts) and high scatter fractions. The

  20. Highly segmented, high resolution time-of-flight system

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

    1991-12-31

    The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

  1. ALICE EXPERIMENT Time of Flight Multigap Resistive Plate Chambers

    CERN Multimedia

    2003-01-01

    Charged particules are identified in ALICE by Time-Of-Flight (TOF); heavier particles are slower and it takes for them longer to reach the outer layers of the detector. For TOF system ALICE uses detectors called Multigap Resistive Plate Chambers (MRPC), like the prototype shown here.

  2. Time-of-flight imaging of invisibility cloaks

    CERN Document Server

    Halimeh, Jad C

    2011-01-01

    As invisibility cloaking has recently become experimental reality, it is interesting to explore ways to reveal remaining imperfections. In essence, the idea of most invisibility cloaks is to recover the optical path lengths without an object (to be made invisible) by a suitable arrangement around that object. Optical path length is proportional to the time of flight of a light ray or to the optical phase accumulated by a light wave. Thus, time-of-flight images provide a direct and intuitive tool for probing imperfections. Indeed, recent phase-sensitive experiments on the carpet cloak have already made early steps in this direction. In the macroscopic world, time-of-flight images could be measured directly by light detection and ranging (LIDAR). Here, we show calculated time-of-flight images of the conformal Gaussian carpet cloak, the conformal grating cloak, the cylindrical free-space cloak, and of the invisible sphere. All results are obtained by using a ray-velocity equation of motion derived from Fermat's ...

  3. Highly segmented, high resolution time-of-flight system

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, T.K.; Nagamiya, S.; Vossnack, O.; Wu, Y.D.; Zajc, W.A. [Columbia Univ., New York, NY (United States); Miake, Y.; Ueno, S.; Kitayama, H.; Nagasaka, Y.; Tomizawa, K.; Arai, I.; Yagi, K [Univ. of Tsukuba, (Japan)

    1991-12-31

    The light attenuation and timing characteristics of time-of-flight counters constructed of 3m long scintillating fiber bundles of different shapes and sizes are presented. Fiber bundles made of 5mm diameter fibers showed good timing characteristics and less light attenuation. The results for a 1.5m long scintillator rod are also presented.

  4. Time-of-flight estimation based on covariance models

    NARCIS (Netherlands)

    van der Heijden, Ferdinand; Tuquerres, G.; Regtien, Paulus P.L.

    We address the problem of estimating the time-of-flight (ToF) of a waveform that is disturbed heavily by additional reflections from nearby objects. These additional reflections cause interference patterns that are difficult to predict. The introduction of a model for the reflection in terms of a

  5. Proposal for Cherenkov Time of Flight Technique with Picosecond Resolution

    Energy Technology Data Exchange (ETDEWEB)

    S. Majewski; A. Margaryan; L. Tang

    2005-08-05

    A new particle identification device for Jlab 12 GeV program is proposed. It is based on the measurement of time information obtained by means of a new photon detector and time measuring concept. The expected time measurement precision for the Cherenkov time-of-flight detector is about or less than 10 picosecond for Cherenkov radiators with lengths less than 50 cm.

  6. Electronics for a Picosecond Time-of-flight Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, Andrew Gerhart [University of Texas, Arlington; Rijssenbeek, Michael [Stony Brook

    2014-11-03

    TITLE: Electronics for a Picosecond Time-of-flight Measurement ABSTRACT: Time-of-flight (TOF) detectors have historically been used as part of the particle identification capability of multi-purpose particle physics detectors. An accurate time measurement, combined with a momentum measurement based on the curvature of the track in a magnetic field, is often sufficient to determine the particle's mass, and thus its identity. Such detectors typically have measured the particle flight time extremely precisely, with an uncertainty of one hundred trillionths of a second (also referred to as 100 picoseconds). To put this in perspective it would be like counting all the people on the Earth and getting it right within 1 person! Another use of TOFs is to measure the vertex of the event, which is the location along the beam line where the incoming particles (typically protons) collide. This vertex positon is a well measured quantity for events where the protons collide “head on” as the outgoing particles produced when you blast the proton apart can be used to trace back to a vertex point from which they originated. More frequently the protons just strike a glancing blow and remain intact—in this case they are nearly parallel to the beam and you cannot tell their vertex without this ability to precisely measure the time of flight of the protons. Occasionally both happen in the same event, that is, a central system and two protons are produced. But are they from the same collision, or just a boring background where more than one collision in the same bunch crossing conspire to fake the signal of interest? That’s where the timing of the protons comes into play. The main idea is to measure the time it takes for the two protons to reach TOF detectors positioned equidistant from the center of the main detector. If the vertex is displaced to one side than that detector will measure a shorter time while the other side detector will measure a correspondingly longer time

  7. Time of Flight Image Segmentation through Co-Regularized Spectral Clustering

    OpenAIRE

    Lorenti, Luciano; Giacomantone, Javier

    2014-01-01

    Time of Flight (TOF) cameras generate two simultaneous images, one for intensity and one for range. This allows tackling segmentation problems where the information pertaining to intensity or range alone is not enough to extract objects of interest from a 3D scene. In this paper, we present a spectral segmentation method that combines information from both images. By modifying the affinity matrix of each of the images based on the other, the segmentation of objects in the scene is improved. T...

  8. The ANTARES recoil time-of-flight spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.W.; Russell, G.J. [New South Wales Univ., Kensington, NSW (Australia); Cohen, D.D.; Dytlewski, N. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    The Australian National Tandem for Applied Research (ANTARES), is a 8MV FN tandem particle accelerator at the Australian Nuclear Science and Technology Organisation. Research on the accelerator is divided between two groups, Accelerator Mass Spectrometry (AMS) and lon Beam Analysis (IBA). The IBA group carries out a range of research projects from nuclear physics to materials characterisation. The major IBA project on the accelerator is a recoil time-of-flight spectrometer which consists of two electrostatic time pulse generators and an ion-implanted surface barrier detector. The spectrometer is ideally suited to the profiling of layered multi-element materials, and has been used to characterise materials such as metal-germanides, optoelectronics, superconductors and catalytic converters. This paper will describe the time-of-flight system as well as some recent materials characterisation results. 1 refs., 3 figs.

  9. A time of flight detector for high energy heavy particles

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Z.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    As a commonly used method to measure the energy of a particle with known mass, the flight time of the particle travelling over a certain distance is measured. A detector based on this principle is called a time-of-flight (TOF) detector which has attracted interests constantly during the last 15 years. For high energy heavy particle energy detection, TOF detector is an appropriated choice and such a system, developed recently, is described in this paper. 8 refs., 3 figs.

  10. Method of Gas Filled Time of Flight in AMS Measurement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Isobaric interference is the main problem to be overcome in determination the long-livedradioisotopes. Energy loss method was used to measurement of these nuclides, but in the low energyaccelerator, the △E-E method is limited. In order to improve the power of isobaric identification in theaccelerator mass spectrometric measurements, a gas-filled time-of-flight (GF-TOF) spectrometric detectorhas been designed and set up.

  11. The time-of-flight detector of the DIRAC experiment

    CERN Document Server

    Adeva, B; Gómez, F; López-Aguera, A; Núñez-Pardo de Vera, M T; Pló, M; Rodríguez, A M; Rodríguez, X M; Saborido, J J; Santamarina-Rios, C; Tobar, M J; Vázquez, P

    2002-01-01

    The construction and performance of a large area time-of-flight detector for the DIRAC experiment at CERN is reported. With an average time resolution of 123 ps per counter at rates up to 1 MHz, it allows excellent separation of ppi**- from pi**+pi**- pairs up to 4.6 GeV/c momentum, as well as of Coulomb-correlated pion pairs from accidentals. The optimization of scintillator material, photomultiplier performance and readout electronics is described.

  12. TORCH - a Cherenkov-based time-of-flight detector

    CERN Document Server

    van Dijk, M W U; Cowie, E N; Cussans, D; D' Ambrosio, C; Forty, R; Frei, C; Gys, T; Piedigrossi, D; Castillo Garcia, L; Fopma, J; Gao, R; Harnew, N; Keri, T

    2014-01-01

    TORCH is an innovative high-precision time-of-flight system to provide particle identification in the difficult intermediate momentum region up to 10 GeV/c. It is also suitable for large-area applications. The detector provides a time-of-flight measurement from the imaging of Cherenkov photons emitted in a 1 cm thick quartz radiator. The photons propagate by total internal reflection to the edge of the quartz plate, where they are focused onto an array of photon detectors at the periphery. A time-of-flight resolution of about 10–15 ps per incident charged particle needs to be achieved for a three sigma kaon–pion separation up to 10 GeV/c momentum for the TORCH located 9.5 m from the interaction point. Given ∼ 30 detected photons per incident charged particle, this requires measuring the time-of-arrival of individual photons to about 70 ps. This paper will describe the design of a TORCH prototype involving a number of ground-breaking and challenging techniques.

  13. Continuous time of flight measurements in a Lissajous configuration

    Science.gov (United States)

    Dobos, G.; Hárs, G.

    2017-01-01

    Short pulses used by traditional time-of-flight mass spectrometers limit their duty cycle, pose space-charge issues, and require high speed detectors and electronics. The motivation behind the invention of continuous time of flight mass spectrometers was to mitigate these problems, by increasing the number of ions reaching the detector and eliminating the need for fast data acquisition systems. The most crucial components of these spectrometers are their modulators: they determine both the maximal modulation frequency and the modulation depth. Through these parameters they limit the achievable mass resolution and signal-to-noise ratio. In this paper, a new kind of setup is presented which modulates the beam by deflecting it in two perpendicular directions and collects ions on a position sensitive detector. Such an Lissajous time of flight spectrometer achieves modulation without the use of slits or apertures, making it possible for all ions to reach the detector, thereby increasing the transmission and signal-to-noise ratio. In this paper, we provide the mathematical description of the system, discuss its properties, and present a practical demonstration of the principle.

  14. Development of an ion time-of-flight spectrometer for neutron depth profiling

    Science.gov (United States)

    Cetiner, Mustafa Sacit

    Ion time-of-flight spectrometry techniques are investigated for applicability to neutron depth profiling. Time-of-flight techniques are used extensively in a wide range of scientific and technological applications including energy and mass spectroscopy. Neutron depth profiling is a near-surface analysis technique that gives concentration distribution versus depth for certain technologically important light elements. The technique uses thermal or sub-thermal neutrons to initiate (n, p) or (n, alpha) reactions. Concentration versus depth distribution is obtained by the transformation of the energy spectrum into depth distribution by using stopping force tables of the projectiles in the substrate, and by converting the number of counts into concentration using a standard sample of known dose value. Conventionally, neutron depth profiling measurements are based on charged particle spectrometry, which employs semiconductor detectors such as a surface barrier detector (SBD) and the associated electronics. Measurements with semiconductor detectors are affected by a number of broadening mechanisms, which result from the interactions between the projectile ion and the detector material as well as fluctuations in the signal generation process. These are inherent features of the detection mechanism that involve the semiconductor detectors and cannot be avoided. Ion time-of-flight spectrometry offers highly precise measurement capabilities, particularly for slow particles. For high-energy low-mass particles, measurement resolution tends to degrade with all other parameters fixed. The threshold for more precise ion energy measurements with respect to conventional techniques, such as direct energy measurement by a surface barrier detector, is directly related to the design and operating parameters of the device. Time-of-flight spectrometry involves correlated detection of two signals by a coincidence unit. In ion time-of-flight spectroscopy, the ion generates the primary input

  15. Layer-by-layer functionalized porous Zinc sulfide nanospheres-based solid-phase extraction combined with liquid chromatography time-of-flight/mass and gas chromatography-mass spectrometry for the specific enrichment and identification of alkaloids from Crinum asiaticum var. sinicum.

    Science.gov (United States)

    Zhu, Dong; Miao, Zhao Yi; Yang, Rui Xiang; Wen, Hong Mei; Li, Wei; Chen, Jun; Kang, An; Shan, Chen-Xiao; Yu, Sheng; Hu, Yue

    2016-08-17

    The current widely utilized polymer or C8, C18 end-capped material-based sorbents for solid-phase extraction could not capture alkaloids well only based on "like dissolves like" principle. In this paper, a layer-by-layer functionalized porous Zinc sulfide nanospheres-based solid-phase extraction (SPE) combined with liquid chromatography time-of-flight/mass spectrometry (LC-TOF/MS) and gas chromatography-mass spectrometry (GC-MS) was developed for the specific enrichment and identification of alkaloids from complex matrixes, Crinum asiaticum var. sinicum crude extracts. The functionalized porous Zinc sulfide nanospheres were prepared by the amidation reaction of poly-(acrylic acid) (PAA) homopolymer with amino groups onto the porous ZnS nanospheres. Tandem LC-TOF/MS spectrometry presented that the almost all of the twenty-three main peaks in elution fraction from the SPE could be inferred as alkaloids with ion of mass according to the nitrogen rule and hit formula with Peak View1.2@software from AB SCIEX, and seven alkaloids including two new found chemical entities were directly identified from their GC-MS spectra and retention indices. We believe that this SPE protocol can also be utilized in the future to selectively enrich alkaloids from extracts of other plant species.

  16. A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

    Science.gov (United States)

    Van Campenhout, Karen; Goenaga Infante, Heidi; Goemans, Geert; Belpaire, Claude; Adams, Freddy; Blust, Ronny; Bervoets, Lieven

    2008-05-15

    The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.

  17. Time-of-flight discrimination between gamma-rays and neutrons by neural networks

    OpenAIRE

    2012-01-01

    In gamma-ray spectroscopy, a number of neutrons are emitted from the nuclei together with the gamma-rays and these neutrons influence gamma-ray spectra. An obvious method of separating between neutrons and gamma-rays is based on the time-of-flight (tof) technique. This work aims obtaining tof distributions of gamma-rays and neutrons by using feed-forward artificial neural network (ANN). It was shown that, ANN can correctly classify gamma-ray and neutron events. Testing of trained networks on ...

  18. ON THE FORMATION AND ISOMER SPECIFIC DETECTION OF PROPENAL (C{sub 2}H{sub 3}CHO) AND CYCLOPROPANONE (c-C{sub 3}H{sub 4}O) IN INTERSTELLAR MODEL ICES—A COMBINED FTIR AND REFLECTRON TIME-OF-FLIGHT MASS SPECTROSCOPIC STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Abplanalp, Matthew J.; Borsuk, Aleca; Jones, Brant M.; Kaiser, Ralf I., E-mail: ralfk@hawaii.edu [W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, Hawaii, HI, 96822 (United States)

    2015-11-20

    The formation routes of two structural isomers—propenal (C{sub 2}H{sub 3}CHO) and cyclopropanone (c-C{sub 3}H{sub 4}O)—were investigated experimentally by exposing ices of astrophysical interest to energetic electrons at 5.5 K thus mimicking the interaction of ionizing radiation with interstellar ices in cold molecular clouds. The radiation-induced processing of these ices was monitored online and in situ via Fourier Transform Infrared spectroscopy and via temperature programmed desorption exploiting highly sensitive reflectron time-of-flight mass spectrometry coupled with single photon ionization in the post irradiation phase. To selectively probe which isomer(s) is/are formed, the photoionization experiments were conducted with 10.49 and 9.60 eV photons. Our studies provided compelling evidence on the formation of both isomers—propenal (C{sub 2}H{sub 3}CHO) and cyclopropanone (c-C{sub 3}H{sub 4}O)—in ethylene (C{sub 2}H{sub 4})—carbon monoxide (CO) ices forming propenal and cyclopropanone at a ratio of (4.5 ± 0.9):1. Based on the extracted reaction pathways, the cyclopropanone molecule can be classified as a tracer of a low temperature non-equilibrium chemistry within interstellar ices involving most likely excited triplet states, whereas propenal can be formed at ultralow temperatures, but also during the annealing phase via non-equilibrium as well as thermal chemistry (radical recombination). Since propenal has been detected in the interstellar medium and our laboratory experiments demonstrate that both isomers originated from identical precursor molecules our study predicts that the hitherto elusive second isomer—cyclopropanone—should also be observable toward those astronomical sources such as Sgr B2(N) in which propenal has been detected.

  19. Time-of-flight flow imaging using NMR remote detection

    Energy Technology Data Exchange (ETDEWEB)

    Granwehr, Josef; Harel, Elad; Han, Song-I; Garcia, Sandra; Pines,Alex; Sen, Pabitra N.; Song, Yi-Qiao

    2005-05-05

    A time-of-flight imaging technique is introduced to visualize fluid flow and dispersion through porous media using NMR. As the fluid flows through a sample, the nuclear spin magnetization is modulated by RF pulses and magnetic field gradients to encode the spatial coordinates of the fluid. When the fluid leaves the sample, its magnetization is recorded by a second RF coil. This scheme not only facilitates a time-dependent imaging of fluid flow, it also allows a separate optimization of encoding and detection subsystems to enhance overall sensitivity. The technique is demonstrated by imaging gas flow through a porous rock.

  20. Bakelite chambers for time-of-flight measurements

    CERN Document Server

    Cwiok, M; Górski, M; Królikowski, J

    1999-01-01

    We report on the search of composite organic materials with the volume resistivity ranging from 10 sup 8 to 10 sup 1 sup 1 OMEGA cm. Materials having resistivity in this range may be used for electrodes of thin gap Parallel Plate Avalanche Chambers. Gas detectors of such structure and operated at increased gas pressure allow, potentially, a sub-nanosecond time resolution. Using bakelite-like material with electrical properties well tuned during manufacturing opens the possibility to overcome limitations related to the semi-conductive glass employed usually for ultrafast gas detectors of parallel plate structure for time-of-flight technique.

  1. An orientable time of flight detector for cosmic rays

    CERN Document Server

    Iori, M

    2007-01-01

    Cosmic ray studies, in particular UHECR, can be in general supported by a directional, easy deployable, simple and robust detector. The design of this detector is based on the time of flight between two parallel tiles of scintillator, to distinguish particle passing through in opposite directions; by fine time resolution and pretty adjustable acceptance it is possible to select upward(left)/downward(right) cosmic rays. It has been developed for an array of detectors to measure upward $\\tau$ from Earth-Skimming neutrino events with energy above $10^8 GeV$. The properties and performances of the detector are discussed. Test results from a high noise environment are presented.

  2. Dissociation of fast ions analyzed by time-of-flight

    Energy Technology Data Exchange (ETDEWEB)

    Ponciano, C.R.; Ladeia, R.C.C.; Collado, V.M.; Silveira, E.F. da [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Fisica]. E-mail: enio@vdg.fis.puc-rio.br

    2001-09-01

    The fragmentation of metastable ions, having keV of kinetic energy, is analyzed by time-of-flight technique. Assuming isotropic distribution of fragments in a free field region, it is deduced an analytical expression to describe the corresponding peak shapes in linear TOF spectrometers. Metastable ion mean-life and the kinetic energy release (Q-value) are the quantities extracted from data fitting. As an illustration, the dissociation of C{sub 8} H{sub 10} N{sup +} metastable ions, desorbed by {sup 252} Cf fission fragment impact on organic target, is studied. (author)

  3. Correction of Errors in Time of Flight Cameras

    OpenAIRE

    Jiménez Cabello, David

    2015-01-01

    En esta tesis se aborda la corrección de errores en cámaras de profundidad basadas en tiempo de vuelo (Time of Flight - ToF). De entre las más recientes tecnologías, las cámaras ToF de modulación continua (Continuous Wave Modulation - CWM) son una alternativa prometedora para la creación de sensores compactos y rápidos. Sin embargo, existen gran variedad de errores que afectan notablemente la medida de profundidad, poniendo en compromiso posibles aplicaciones. La...

  4. Material Classification Using Raw Time-of-Flight Measurements

    KAUST Repository

    Su, Shuochen

    2016-12-13

    We propose a material classification method using raw time-of-flight (ToF) measurements. ToF cameras capture the correlation between a reference signal and the temporal response of material to incident illumination. Such measurements encode unique signatures of the material, i.e. the degree of subsurface scattering inside a volume. Subsequently, it offers an orthogonal domain of feature representation compared to conventional spatial and angular reflectance-based approaches. We demonstrate the effectiveness, robustness, and efficiency of our method through experiments and comparisons of real-world materials.

  5. Time of Flight Transients in the Dipolar Glass Model

    OpenAIRE

    2013-01-01

    Using Monte Carlo simulation we investigated time of flight current transients predicted by the dipolar glass model for a random spatial distribution of hopping centers. Behavior of the carrier drift mobility was studied at room temperature over a broad range of electric field and sample thickness. A flat plateau followed by $j\\propto t^{-2}$ current decay is the most common feature of the simulated transients. Poole-Frenkel mobility field dependence was confirmed over 5 to 200 V/$\\mu$m as we...

  6. Time of flight Laue fiber diffraction studies of perdeuterated DNA

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, V.T.; Whalley, M.A.; Mahendrasingam, A.; Fuller, W. [Keele Univ. (United Kingdom)] [and others

    1994-12-31

    The diffractometer SXD at the Rutherford Appleton Laboratory ISIS pulsed neutron source has been used to record high resolution time-of-flight Laue fiber diffraction data from DNA. These experiments, which are the first of their kind, were undertaken using fibers of DNA in the A conformation and prepared using deuterated DNA in order to minimis incoherent background scattering. These studies complement previous experiments on instrument D19 at the Institute Laue Langevin using monochromatic neutrons. Sample preparation involved drawing large numbers of these deuterated DNA fibers and mounting them in a parallel array. The strategy of data collection is discussed in terms of camera design, sample environment and data collection. The methods used to correct the recorded time-of-flight data and map it into the final reciprocal space fiber diffraction dataset are also discussed. Difference Fourier maps showing the distribution of water around A-DNA calculated on the basis of these data are compared with results obtained using data recorded from hydrogenated A-DNA on D19. Since the methods used for sample preparation, data collection and data processing are fundamentally different for the monochromatic and Laue techniques, the results of these experiments also afford a valuable opportunity to independently test the data reduction and analysis techniques used in the two methods.

  7. Electrospray ionization quadrupole time-of-flight tandem mass spectrometric analysis of hexamethylenediamine-modified maltodextrin and dextran

    NARCIS (Netherlands)

    Sisu, E.; Bosker, W.T.E.; Norde, W.; Slaghek, T.M.; Timmermans, J.W.; Peter-Katalinić, J.; Cohen-Stuart, M.A.; Zamfir, A.D.

    2006-01-01

    A combined methodology for obtaining at the preparative scale and characterization by nanoelectrospray ionization (nanoESI) quadrupole time-of-flight (QTOF) mass spectrometry (MS) and tandem MS (MS/MS) of linear polysaccharides modified at the reducing end is presented. Two polydisperse maltodextrin

  8. Energy and time of flight measurements of REX-ISOLDE stable beams using Si detectors

    CERN Document Server

    Cantero, E D; Fraser, M A; Lanaia, D; Sosa, A; Voulot, D; Zocca, F

    2014-01-01

    In this paper we present energy and time spectroscopy measurements for the stable beams of REX-ISOLDE obtained using Si detectors. By using an alpha source as a calibration reference, the absolute energy E of stable beam particles (A/q = 4) was determined in spectroscopy mode in the energy range 1 MeV < E < 8 MeV (0.30 MeV/u < E/A < 1.87 MeV/u). The time of flight of the beam particles (2.18 MeV/u < E/A < 2.27 MeV/u) was determined by installing identical Si detectors in two diagnostic boxes separated by 7.7 m. The results obtained with these two techniques are compared with the values obtained by dipole scans using a bending magnet. The measurements took place between January and February of 2013.

  9. FOCUS: time-of-flight spectrometer for cold neutrons at SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, S.; Mesot, J. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland); Hempelmann, R. [Saarbruecken Univ., Physical Chemistry, Saarbruecken (Germany)

    1996-11-01

    The physical layout of the Time-Of-Flight spectrometer at the new spallation source SINQ is presented. The concept shows up a hybrid-TOF combining a Fermi-chopper with a crystal monochromator. The demand of a versatile and flexible instrument for several applications is taken into account by the option of switching from time-focusing to monochromatic focusing mode such that the spectrometer can be optimised for both quasielastic and inelastic scattering applications. (author) 5 figs., 2 tabs., 16 refs.

  10. Multi-MHz time-of-flight electronic bandstructure imaging of graphene on Ir(111)

    Energy Technology Data Exchange (ETDEWEB)

    Tusche, C., E-mail: c.tusche@fz-juelich.de [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Goslawski, P.; Engel, D.; Jankowiak, A. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin (Germany); Kutnyakhov, D.; Elmers, H. J.; Chernov, S.; Wallauer, R.; Schönhense, G. [Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz (Germany); Ellguth, M. [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz (Germany); Medjanik, K. [Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz (Germany); MAX IV Laboratory, Ole Römers vag 1, 22363 Lund (Sweden)

    2016-06-27

    In the quest for detailed spectroscopic insight into the electronic structure at solid surfaces in a large momentum range, we have developed an advanced experimental approach. It combines the 3D detection scheme of a time-of-flight momentum microscope with an optimized filling pattern of the BESSY II storage ring. Here, comprehensive data sets covering the full surface Brillouin zone have been used to study faint substrate-film hybridization effects in the electronic structure of graphene on Ir(111), revealed by a pronounced linear dichroism in angular distribution. The method paves the way to 3D electronic bandmapping with unprecedented data recording efficiency.

  11. Time-of-Flight Cameras in Computer Graphics

    DEFF Research Database (Denmark)

    Kolb, Andreas; Barth, Erhardt; Koch, Reinhard

    2010-01-01

    A growing number of applications depend on accurate and fast 3D scene analysis. Examples are model and lightfield acquisition, collision prevention, mixed reality, and gesture recognition. The estimation of a range map by image analysis or laser scan techniques is still a time-consuming and expen...... devices” for gaming, web-conferencing, and numerous other applications. This STAR gives an account of recent developments in ToF-technology and discusses the current state of the integration of this technology into various graphics-related applications.......-consuming and expensive part of such systems. A lower-priced, fast and robust alternative for distance measurements are Time-of-Flight (ToF) cameras. Recently, significant advances have been made in producing low-cost and compact ToF-devices, which have the potential to revolutionize many fields of research, including...

  12. Time-of-Flight Sensors in Computer Graphics

    DEFF Research Database (Denmark)

    Kolb, Andreas; Barth, Erhardt; Koch, Reinhard

    2009-01-01

    Abstract A growing number of applications depend on accurate and fast 3D scene analysis. Examples are model and lightfield acquisition, collision prevention, mixed reality, and gesture recognition. The estimation of a range map by image analysis or laser scan techniques is still a time-consuming ......-time geometry devices” for gaming, web-conferencing, and numerous other applications. This STAR gives an account of recent developments in ToF-technology and discusses the current state of the integration of this technology into various graphics-related applications.......-consuming and expensive part of such systems. A lower-priced, fast and robust alternative for distance measurements are Time-of-Flight (ToF) cameras. Recently, significant improvements have been made in order to achieve low-cost and compact ToF-devices, that have the potential to revolutionize many fields of research...

  13. Tests and calibration of NIF neutron time of flight detectors.

    Science.gov (United States)

    Ali, Z A; Glebov, V Yu; Cruz, M; Duffy, T; Stoeckl, C; Roberts, S; Sangster, T C; Tommasini, R; Throop, A; Moran, M; Dauffy, L; Horsefield, C

    2008-10-01

    The National Ignition Facility (NIF) neutron time of flight (NTOF) diagnostic will measure neutron yield and ion temperature in all NIF campaigns in DD, DT, and THD(*) implosions. The NIF NTOF diagnostic is designed to measure neutron yield from 1x10(9) to 2x10(19). The NTOF consists of several detectors of varying sensitivity located on the NIF at about 5 and 20 m from the target. Production, testing, and calibration of the NIF NTOF detectors have begun at the Laboratory for Laser Energetics (LLE). Operational tests of the NTOF detectors were performed on several facilities including the OMEGA laser at LLE and the Titan laser at Lawrence Livermore National Laboratory. Neutron calibrations were carried out on the OMEGA laser. Results of the NTOF detector tests and calibration will be presented.

  14. Accurate Fiber Length Measurement Using Time-of-Flight Technique

    Science.gov (United States)

    Terra, Osama; Hussein, Hatem

    2016-06-01

    Fiber artifacts of very well-measured length are required for the calibration of optical time domain reflectometers (OTDR). In this paper accurate length measurement of different fiber lengths using the time-of-flight technique is performed. A setup is proposed to measure accurately lengths from 1 to 40 km at 1,550 and 1,310 nm using high-speed electro-optic modulator and photodetector. This setup offers traceability to the SI unit of time, the second (and hence to meter by definition), by locking the time interval counter to the Global Positioning System (GPS)-disciplined quartz oscillator. Additionally, the length of a recirculating loop artifact is measured and compared with the measurement made for the same fiber by the National Physical Laboratory of United Kingdom (NPL). Finally, a method is proposed to relatively correct the fiber refractive index to allow accurate fiber length measurement.

  15. Time Of Flight Detectors: From phototubes to SiPM

    Energy Technology Data Exchange (ETDEWEB)

    Laurenti, G. [INFN of Bologna, Viale B.Pichat 4/2, 40127 Bologna (Italy); Levi, G.; Foschi, E.; Guandalini, C.; Quadrani, L. [Department of Physics and INFN, Viale B.Pichat 4/2, 40127 Bologna (Italy); Sbarra, C. [Department of Physics and INFN, Viale B.Pichat 4/2, 40127 Bologna (Italy); Enrico Fermi Research Center, Via Panisperna 89, 06100 Roma (Italy)], E-mail: cristina.sbarra@bo.infn.it; Zuffa, M. [INFN of Bologna, Viale B.Pichat 4/2, 40127 Bologna (Italy)

    2008-04-01

    A sample of Silicon Photomultipliers was tested because they looked promising for future space missions: low consumption, low weight, resistance to radiation damage and insensitivity to magnetic fields. They have been studied in laboratory by means of the same characterization methods adopted to calibrate the fine mesh photomultipliers used by the Time Of Flight of the AMS-02 experiment. A detailed simulation was made to reproduce the SiPM response to the various experimental conditions. A possible counter design has been studied with front end electronics card equipped with SiPMs and Peltier cell for thermoregulation. A proper simulation based on COMSOL Multiphysics package reproduces quite well the Peltier cell nominal cooling capability.

  16. Inverse time-of-flight spectrometer for beam plasma research

    Energy Technology Data Exchange (ETDEWEB)

    Yushkov, Yu. G., E-mail: yuyushkov@gmail.com; Zolotukhin, D. B.; Tyunkov, A. V. [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Oks, E. M. [Tomsk State University of Control Systems and Radioelectronics, 40 Lenin Ave., Tomsk 634050 (Russian Federation); Institute of High Current Electronics SB RAS, 2/3, Akademichesky Ave., Tomsk 634055 (Russian Federation); Savkin, K. P. [Institute of High Current Electronics SB RAS, 2/3, Akademichesky Ave., Tomsk 634055 (Russian Federation)

    2014-08-15

    The paper describes the design and principle of operation of an inverse time-of-flight spectrometer for research in the plasma produced by an electron beam in the forevacuum pressure range (5–20 Pa). In the spectrometer, the deflecting plates as well as the drift tube and the primary ion beam measuring system are at high potential with respect to ground. This provides the possibility to measure the mass-charge constitution of the plasma created by a continuous electron beam with a current of up to 300 mA and electron energy of up to 20 keV at forevacuum pressures in the chamber placed at ground potential. Research results on the mass-charge state of the beam plasma are presented and analyzed.

  17. Ion trap with integrated time-of-flight mass spectrometer

    CERN Document Server

    Schneider, Christian; Yu, Peter; Hudson, Eric R

    2015-01-01

    Recently, we reported an ion trap experiment with an integrated time-of-flight mass spectrometer (TOFMS) [Phys. Rev. Appl. 2, 034013 (2014)] focussing on the improvement of mass resolution and detection limit due to sample preparation at millikelvin temperatures. The system utilizes a radio-frequency (RF) ion trap with asymmetric drive for storing and manipulating laser-cooled ions and features radial extraction into a compact $275$ mm long TOF drift tube. The mass resolution exceeds $m / \\Delta m = 500$, which provides isotopic resolution over the whole mass range of interest in current experiments and constitutes an improvement of almost an order of magnitude over other implementations. In this manuscript, we discuss the experimental implementation in detail, which is comprised of newly developed drive electronics for generating the required voltages to operate RF trap and TOFMS, as well as control electronics for regulating RF outputs and synchronizing the TOFMS extraction.

  18. Video Guidance Sensor and Time-of-Flight Rangefinder

    Science.gov (United States)

    Bryan, Thomas; Howard, Richard; Bell, Joseph L.; Roe, Fred D.; Book, Michael L.

    2007-01-01

    A proposed video guidance sensor (VGS) would be based mostly on the hardware and software of a prior Advanced VGS (AVGS), with some additions to enable it to function as a time-of-flight rangefinder (in contradistinction to a triangulation or image-processing rangefinder). It would typically be used at distances of the order of 2 or 3 kilometers, where a typical target would appear in a video image as a single blob, making it possible to extract the direction to the target (but not the orientation of the target or the distance to the target) from a video image of light reflected from the target. As described in several previous NASA Tech Briefs articles, an AVGS system is an optoelectronic system that provides guidance for automated docking of two vehicles. In the original application, the two vehicles are spacecraft, but the basic principles of design and operation of the system are applicable to aircraft, robots, objects maneuvered by cranes, or other objects that may be required to be aligned and brought together automatically or under remote control. In a prior AVGS system of the type upon which the now-proposed VGS is largely based, the tracked vehicle is equipped with one or more passive targets that reflect light from one or more continuous-wave laser diode(s) on the tracking vehicle, a video camera on the tracking vehicle acquires images of the targets in the reflected laser light, the video images are digitized, and the image data are processed to obtain the direction to the target. The design concept of the proposed VGS does not call for any memory or processor hardware beyond that already present in the prior AVGS, but does call for some additional hardware and some additional software. It also calls for assignment of some additional tasks to two subsystems that are parts of the prior VGS: a field-programmable gate array (FPGA) that generates timing and control signals, and a digital signal processor (DSP) that processes the digitized video images. The

  19. FPGA-based High-precision Measurement Algorithm for the Ultrasonic Echo Time of Flight

    Institute of Scientific and Technical Information of China (English)

    Bo-xiong WANG; Jin ZHANG

    2010-01-01

    Based on the evaluation of advantages and disadvantages of high-precision digital time interval measuring algorithms, and combined with the principle of the typical time-difference ultrasonic flow measurement,the requirements far the measurement of echo time of flight put forward by the ultrasonic flow measurement are an-alyzed.A new high-precision time interval measurement algorithm is presented, which combines the pulse counting method with the phase delay interpolation. The pulse counting method is used to ensure a large dynamic measuring range, and a double-edge triggering counter is designed to improve the accuracy and reduce the counting quantiza-tion error.The phase delay interpolation is used to reduce the quanti-zation error of pulse counting for further improving the time measure-ment resolution.Test data show that the system for the measurement of the ultrasonic echo time of flight based on this algorithm and im-plemented on an Field Programmable Gate Array(FPGA) needs a rel-atively short time for measurement,and has a measurement error of less than 105 ps.

  20. Polarisation analysis on the LET time-of-flight spectrometer

    Science.gov (United States)

    Nilsen, G. J.; Košata, J.; Devonport, M.; Galsworthy, P.; Bewley, R. I.; Voneshen, D. J.; Dalgliesh, R.; Stewart, J. R.

    2017-06-01

    We present a design for implementing uniaxial polarisation analysis on the LET cold neutron time-of-flight spectrometer, installed on the second target station at ISIS. The polarised neutron beam is to be produced by a transmission-based supermirror polariser with the polarising mirrors arranged in a “double-V” formation. This will be followed by a Mezei-type precession coil spin flipper, selected for its small spatial requirements, as well as a permanent magnet guide field to transport the beam polarisation to the sample position. The sample area will contain a set of holding field coils, whose purpose is to produce a highly homogenous magnetic field for the wide-angle 3He analyser cell. To facilitate fast cell changes and reduce the risk of cell failure, we intend to separate the cell and cryostat from the vacuum of the sample tank by installing both in a vessel at atmospheric pressure. When the instrument upgrade is complete, the performance of LET is expected to be commensurate with existing and planned polarised cold neutron spectrometers at other sources. Finally, we discuss the implications of performing uniaxial polarisation analysis only, and identify quasi-elastic neutron scattering (QENS) on ionic conducting materials as an interesting area to apply the technique.

  1. Proton Transfer Time-of-Flight Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Thomas B [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    The Proton Transfer Reaction Mass Spectrometer (PTRMS) measures gas-phase compounds in ambient air and headspace samples before using chemical ionization to produce positively charged molecules, which are detected with a time-of-flight (TOF) mass spectrometer. This ionization method uses a gentle proton transfer reaction method between the molecule of interest and protonated water, or hydronium ion (H3O+), to produce limited fragmentation of the parent molecule. The ions produced are primarily positively charged with the mass of the parent ion, plus an additional proton. Ion concentration is determined by adding the number of ions counted at the molecular ion’s mass-to-charge ratio to the number of air molecules in the reaction chamber, which can be identified according to the pressure levels in the reaction chamber. The PTRMS allows many volatile organic compounds in ambient air to be detected at levels from 10–100 parts per trillion by volume (pptv). The response time is 1 to 10 seconds.

  2. Proposed STAR Time of Flight Readout Electronics and DAQ

    Science.gov (United States)

    Schambach, Joachim

    2006-04-01

    A novel Time-of-Flight (TOF) subsystem is under design for the STAR detector at RHIC. A total of 3840 Multi-gap Resistive Plate Chambers (MRPC) of 6 pads each are distributed over 120 trays. The total number of channels is 23040. Each TOF tray consists of 192 detector channels and three different types of electronic circuit cards, called "TINO", "TDIG", and "TCPU", listed in order of the data flow. Every 30 trays send their data to a "THUB" card that interfaces to the STAR trigger and transmits the data over a fiber to a fiber receiver which is part of STAR DAQ. The TINO contains the analog front end electronics based on a custom IC called NINO. The output of TINO is passed to the TDIG, where the data are digitized (using the CERN HPTDC ASIC). The TCPU formats and buffers the digital detector information. This formatted data is passed to THUB, which transmits it over an optical fiber to a data receiver in the STAR DAQ room. The architecture of this readout chain and DAQ will be described, and first results from prototypes of the component boards will be discussed.

  3. The diamond time of flight detector of the TOTEM experiment

    Science.gov (United States)

    Berretti, Mirko

    2017-02-01

    This contribution describes the design and the performance of a novel timing detector developed by the TOTEM Collaboration. The detector will be installed inside the TOTEM Roman Pots (RPs) and will measure the Time-Of-Flight (TOF) of the protons produced in the central diffractive (CD) interactions at the LHC. In particular, the measurement of the proton TOF allows the determination of the vertex longitudinal position where the protons are produced, thus allowing the protons association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal CVD (scCVD) diamond plates and it is designed in order to measure the protons TOF with 50 ps time resolution. To achieve this performance, a dedicated fast and low noise electronics for the signal amplification has been developed. Indeed, while diamond sensors have lower noise and faster signals than silicon sensors, the amount of charge released in the medium is lower. The digitization of the diamond signal is performed sampling the waveform at 10 GSa/s with the SAMPIC chip. The performance of the first TOF detector installed in the LHC in November 2015 will be reported. An overview of the clock distribution system and of the control system which interfaces the timing detectors to the experiment DAQ is finally given.

  4. Positron Emission Tomography (PET): Towards Time of Flight

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Joel (University of Pennsylvania)

    2004-09-29

    PET is a powerful imaging tool that is being used to study cancer, using a variety of tracers to measure physiological processes including glucose metabolism, cell proliferation, and hypoxia in tumor cells. As the utilization of PET has grown in the last several years, it has become clear that improved lesion detection and quantification are critical goals for cancer studies. Although physical performance of the current generation of PET scanners has improved recently, there are limitations especially for heavy patients where attenuation and scatter effects are increased. We are investigating new scintillation detectors, scanner designs, and image processing algorithms in order to overcome these limitations and improve performance. In particular, we are studying scanner designs that would incorporate scintillators with improved energy and timing resolution. Improved energy resolution helps to reduce scattered radiation, and improved timing resolution makes it feasible to incorporate the time-of-flight information between the two coincident gamma rays into the image reconstruction algorithm, a technique that improves signal-to-noise. Results of recent experiments and computer simulations will be shown to demonstrate these potential improvements.

  5. Instrumentation for time of-flight position emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, Muhammad Nasir; Pratiwi, Eva; Yeom, Jung Yeol [Korea University, Seoul (Korea, Republic of); Cheon, Ji Min; Choi, Ho Jung [Kumoh National Institute of Technology, Gumi (Korea, Republic of)

    2016-06-15

    Positron emission tomography (PET) is a molecular imaging modality that provides information at the molecular level. This system is composed of radiation detectors to detect incoming coincident annihilation gamma photons emitted from the radiopharmaceutical injected into a patient's body and uses these data to reconstruct images. A major trend in PET instrumentation is the development of time-of-flight positron emission tomography (ToF-PET). In ToF-PET, the time information (the instant the radiation is detected) is incorporated for image reconstruction. Therefore, precise and accurate timing recording is crucial in ToF-PET. ToF-PET leads to better localization of the annihilation event and thus results in overall improvement in the signal-to-noise ratio (SNR) of the reconstructed image. Several factors affect the timing performance of ToF-PET. In this article, the background, early research and recent advances in ToF-PET instrumentation are presented. Emphasis is placed on the various types of scintillators, photodetectors and electronic circuitry for use in ToF-PET, and their impact on timing resolution is discussed.

  6. Time-of-flight Extreme Environment Diffractometer at the Helmholtz-Zentrum Berlin.

    Science.gov (United States)

    Prokhnenko, Oleksandr; Stein, Wolf-Dieter; Bleif, Hans-Jürgen; Fromme, Michael; Bartkowiak, Maciej; Wilpert, Thomas

    2015-03-01

    The Extreme Environment Diffractometer (EXED) is a new neutron time-of-flight instrument at the BER II research reactor at the Helmholtz-Zentrum Berlin, Germany. Although EXED is a special-purpose instrument, its early construction made it available for users as a general-purpose diffractometer. In this respect, EXED became one of the rare examples, where the performance of a time-of-flight diffractometer at a continuous source can be characterized. In this paper, we report on the design and performance of EXED with an emphasis on the unique instrument capabilities. The latter comprise variable wavelength resolution and wavelength band, control of the incoming beam divergence, the possibility to change the angular positions of detectors and their distance to the sample, and use of event recording and offline histogramming. These features combined make EXED easily tunable to the requirements of a particular problem, from conventional diffraction to small angle neutron scattering. The instrument performance is demonstrated by several reference measurements and user experiments.

  7. Optimal rebinning of time-of-flight PET data.

    Science.gov (United States)

    Ahn, Sangtae; Cho, Sanghee; Li, Quanzheng; Lin, Yanguang; Leahy, Richard M

    2011-10-01

    Time-of-flight (TOF) positron emission tomography (PET) scanners offer the potential for significantly improved signal-to-noise ratio (SNR) and lesion detectability in clinical PET. However, fully 3D TOF PET image reconstruction is a challenging task due to the huge data size. One solution to this problem is to rebin TOF data into a lower dimensional format. We have recently developed Fourier rebinning methods for mapping TOF data into non-TOF formats that retain substantial SNR advantages relative to sinograms acquired without TOF information. However, mappings for rebinning into non-TOF formats are not unique and optimization of rebinning methods has not been widely investigated. In this paper we address the question of optimal rebinning in order to make full use of TOF information. We focus on FORET-3D, which approximately rebins 3D TOF data into 3D non-TOF sinogram formats without requiring a Fourier transform in the axial direction. We optimize the weighting for FORET-3D to minimize the variance, resulting in H(2)-weighted FORET-3D, which turns out to be the best linear unbiased estimator (BLUE) under reasonable approximations and furthermore the uniformly minimum variance unbiased (UMVU) estimator under Gaussian noise assumptions. This implies that any information loss due to optimal rebinning is as a result only of the approximations used in deriving the rebinning equation and developing the optimal weighting. We demonstrate using simulated and real phantom TOF data that the optimal rebinning method achieves variance reduction and contrast recovery improvement compared to nonoptimized rebinning weightings. In our preliminary study using a simplified simulation setup, the performance of the optimal rebinning method was comparable to that of fully 3D TOF MAP. © 2011 IEEE

  8. LVGEMS Time-of-Flight Mass Spectrometry on Satellites

    Science.gov (United States)

    Herrero, Federico

    2013-01-01

    NASA fs investigations of the upper atmosphere and ionosphere require measurements of composition of the neutral air and ions. NASA is able to undertake these observations, but the instruments currently in use have their limitations. NASA has extended the scope of its research in the atmosphere and now requires more measurements covering more of the atmosphere. Out of this need, NASA developed multipoint measurements using miniaturized satellites, also called nanosatellites (e.g., CubeSats), that require a new generation of spectrometers that can fit into a 4 4 in. (.10 10 cm) cross-section in the upgraded satellites. Overall, the new mass spectrometer required for the new depth of atmospheric research must fulfill a new level of low-voltage/low-power requirements, smaller size, and less risk of magnetic contamination. The Low-Voltage Gated Electrostatic Mass Spectrometer (LVGEMS) was developed to fulfill these requirements. The LVGEMS offers a new spectrometer that eliminates magnetic field issues associated with magnetic sector mass spectrometers, reduces power, and is about 1/10 the size of previous instruments. LVGEMS employs the time of flight (TOF) technique in the GEMS mass spectrometer previously developed. However, like any TOF mass spectrometer, GEMS requires a rectangular waveform of large voltage amplitude, exceeding 100 V -- that means that the voltage applied to one of the GEMS electrodes has to change from 0 to 100 V in a time of only a few nanoseconds. Such electronic speed requires more power than can be provided in a CubeSat. In the LVGEMS, the amplitude of the rectangular waveform is reduced to about 1 V, compatible with digital electronics supplies and requiring little power.

  9. Sensors for Using Times of Flight to Measure Flow Velocities

    Science.gov (United States)

    Fralick, Gutave; Wrbanek, John D.; Hwang, Danny; Turso, James

    2006-01-01

    Thin-film sensors for measuring flow velocities in terms of times of flight are undergoing development. These sensors are very small and can be mounted flush with surfaces of airfoils, ducts, and other objects along which one might need to measure flows. Alternatively or in addition, these sensors can be mounted on small struts protruding from such surfaces for acquiring velocity measurements at various distances from the surfaces for the purpose of obtaining boundary-layer flow-velocity profiles. These sensors are related to, but not the same as, hot-wire anemometers. Each sensor includes a thin-film, electrically conductive loop, along which an electric current is made to flow to heat the loop to a temperature above that of the surrounding fluid. Instantaneous voltage fluctuations in segments of the loop are measured by means of electrical taps placed at intervals along the loop. These voltage fluctuations are caused by local fluctuations in electrical resistance that are, in turn, caused by local temperature fluctuations that are, in turn, caused by fluctuations in flow-induced cooling and, hence, in flow velocity. The differential voltage as a function of time, measured at each pair of taps, is subjected to cross-correlation processing with the corresponding quantities measured at other pairs of taps at different locations on the loop. The cross-correlations yield the times taken by elements of fluid to travel between the pairs of taps. Then the component of velocity along the line between any two pairs of taps is calculated simply as the distance between the pairs of taps divided by the travel time. Unlike in the case of hot-wire anemometers, there is no need to obtain calibration data on voltage fluctuations versus velocity fluctuations because, at least in principle, the correlation times are independent of the calibration data.

  10. Readout Strategy of an Electro-optical Coupled PET Detector for Time-of-Flight PET/MRI

    OpenAIRE

    Bieniosek, M F; Olcott, P D; Levin, C. S.

    2013-01-01

    Combining PET with MRI in a single system provides clinicians with complementary molecular and anatomical information. However, existing integrated PET/MRI systems do not have time-of-flight PET capabilities. This work describes an MRI-compatible front-end electronic system with ToF capabilities. The approach employs a fast arrival-time pickoff comparator to digitize the timing information, and a laser diode to drive a 10m fiber-optic cable to optically transmit asynchronous timing informatio...

  11. Temporary Polarisation Insert for a Time-of-Flight Neutron Reflectometer

    CERN Document Server

    Kreuzpaintner, Wolfgang; Moulin, Jean-François; Wiedemann, Birgit; Ye, Jingfan; Mayr, Sina; Paul, Amitesh; Haese, Martin; Pomm, Matthias; Böni, Peter

    2016-01-01

    The suitability of a transportable 3He-spin filter as broadband polariser for a Time-of-Flight neutron reflectometer in combination with a proposed characterisation method for 3He-spin filters is presented. Both, the experimental simplicity and the data treatment procedure for extracting the spin-up and spin-down neutron reflectivity from measurements obtained for a time dependent 3He polarisation, are shown. For benchmarking, the extraction of a very weak magnetic signal from reflectivity data, measured on the magnetic heterostructure Fe(1nm)/Cu(20nm)/Si(substrate) in an externally applied magnetic field of 30 mT is demonstrated and compared to similar measurements on Cu(20nm)/Si(substrate), which show no magnetic signal.

  12. An indigenous cluster beam apparatus with a reflectron time-of-flight mass spectrometer

    Indian Academy of Sciences (India)

    G Raina; G U Kulkarni; R T Yadav; V S Ramamurthy; C N R Rao

    2000-04-01

    The design and fabrication of a Smalley-type cluster source in combination with a reflectron based time-of-flight (TOF) mass spectrometer are reported. The generation of clusters is based on supersonic jet expansion of the sampling plume. Sample cells for both liquid and solid targets developed for this purpose are described. Two pulsed Nd-YAG lasers are used in tandem, one (532 nm) for target vapourization and the other (355 nm) for cluster ionization. Methanol clusters of nuclearity up to 14 (mass 500 amu) were produced from liquid methanol as the test sample. The clusters were detected with a mass resolution of ~ 2500 in the R-TOF geometry. Carbon clusters up to a nuclearity of 28 were obtained using a polyimide target. The utility of the instrument is demonstrated by carrying out experiments to generate mixed clusters from alcohol mixtures.

  13. A High-Resolution Time-of-Flight Mass Spectrometer for Experiments with Ultracold Gases

    CERN Document Server

    Kraft, S D; Staanum, P; Fioretti, A; Lange, J; Wester, R; Weidemüller, M; Kraft, Stephan D.; Mikosch, Jochen; Staanum, Peter; Fioretti, Andrea; Lange, Joerg; Wester, Roland; Weidemueller, Matthias

    2005-01-01

    We have realized a high-resolution time-of-flight mass spectrometer combined with a magneto-optical trap. The spectrometer enables excellent optical access to the trapped atomic cloud using properly devised acceleration and deflection electrodes. The ions are extracted along a laser axis and deflected onto an off axis detector. The setup is applied to detect atoms and molecules photoassociated from ultracold atoms. The detection is based on resonance-enhanced multi-photon ionization. The versatile setup can easily be implemented in more complex experiments with ultracold atomic and molecular gases. Mass resolution up to $m/\\Delta m_{rms} = 1000$ at the mass of $^{133}$Cs is achieved.

  14. Analyzing neutron time-of-flight spectra from the National Ignition Facility using moments

    Science.gov (United States)

    Hatarik, R.; Field, J.; Eckart, M.; Grim, G.; Hartouni, E. P.; Moore, A.; Munro, D.; Sayre, D.

    2016-10-01

    The neutron spectrum produced by an indirectly driven implosion at the National Ignition Facility (NIF) provides valuable insight into the performance of the capsule. There are four neutron time-of-flight (nTOF) spectrometers being used at the NIF which can simultaneously measure DD and DT fusion neutrons on NIF shots. The width of theses peaks have been traditionally associated with the temperature of the plasma, recent work shows that it has to be considered a combination of flow and temperature distributions. This leads to a deviation from a pure gaussian shape of a single temperature static plasma and the presence of higher order moments in the neutron spectrum. The current status of the analysis of neutron spectra from the nTOF diagnostics at the NIF will be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  15. Joint Temperature-Lasing Mode Compensation for Time-of-Flight LiDAR Sensors

    Directory of Open Access Journals (Sweden)

    Anas Alhashimi

    2015-12-01

    Full Text Available We propose an expectation maximization (EM strategy for improving the precision of time of flight (ToF light detection and ranging (LiDAR scanners. The novel algorithm statistically accounts not only for the bias induced by temperature changes in the laser diode, but also for the multi-modality of the measurement noises that is induced by mode-hopping effects. Instrumental to the proposed EM algorithm, we also describe a general thermal dynamics model that can be learned either from just input-output data or from a combination of simple temperature experiments and information from the laser’s datasheet. We test the strategy on a SICK LMS 200 device and improve its average absolute error by a factor of three.

  16. Probing nanoparticles and nanoparticle-conjugated biomolecules using time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Kim, Young-Pil; Shon, Hyun Kyong; Shin, Seung Koo; Lee, Tae Geol

    2015-01-01

    Bio-conjugated nanoparticles have emerged as novel molecular probes in nano-biotechnology and nanomedicine and chemical analyses of their surfaces have become challenges. The time-of-flight (TOF) secondary ion mass spectrometry (SIMS) has been one of the most powerful surface characterization techniques for both nanoparticles and biomolecules. When combined with various nanoparticle-based signal enhancing strategies, TOF-SIMS can probe the functionalization of nanoparticles as well as their locations and interactions in biological systems. Especially, nanoparticle-based SIMS is an attractive approach for label-free drug screening because signal-enhancing nanoparticles can be designed to directly measure the enzyme activity. The chemical-specific imaging analysis using SIMS is also well suited to screen nanoparticles and nanoparticle-biomolecule conjugates in complex environments. This review presents some recent applications of nanoparticle-based TOF-SIMS to the chemical analysis of complex biological systems.

  17. HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    SHAPIRO,S.M.; ZALIZNYAK,I.A.

    2002-12-30

    This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual

  18. Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

    DEFF Research Database (Denmark)

    Jacobsen, Asger Schou; Salewski, Mirko; Eriksson, J.;

    2014-01-01

    spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly...

  19. Wide-band mass measurements with a multi-reflection time-of-flight mass spectrograph

    CERN Document Server

    Schury, P; Wada, M; Wollnik, H

    2013-01-01

    We characterize the mass bandwidth of the a multi-reflection time-of-flight mass spectrograph, showing both the functional and useful mass bandwidth. We then demonstrate the use of a multi-reflection time-of-flight mass spectrograph to perform mass measurements in mass bands much wider than the mass bandwidth.

  20. Optimizing sequence coverage for a moderate mass protein in nano-electrospray ionization quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Matsuda, Ryan; Kolli, Venkata; Woods, Megan; Dodds, Eric D; Hage, David S

    2016-09-15

    Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C, and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA.

  1. Miniature Time of Flight Mass Spectrometer for Space and Extraterrestrial Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The PI has developed a miniature time-of-flight mass spectrometer (TOF-MS), which can be op-timized for space and extraterrestrial applications, by using a...

  2. High-throughput shotgun lipidomics by quadrupole time-of-flight mass spectrometry

    DEFF Research Database (Denmark)

    Ståhlman, Marcus; Ejsing, Christer S.; Tarasov, Kirill;

    2009-01-01

    Technological advances in mass spectrometry and meticulous method development have produced several shotgun lipidomic approaches capable of characterizing lipid species by direct analysis of total lipid extracts. Shotgun lipidomics by hybrid quadrupole time-of-flight mass spectrometry allows...

  3. Single view reflectance capture using multiplexed scattering and time-of-flight imaging

    OpenAIRE

    Zhao, Shuang; Velten, Andreas; Raskar, Ramesh; Bala, Kavita; Naik, Nikhil Deepak

    2011-01-01

    This paper introduces the concept of time-of-flight reflectance estimation, and demonstrates a new technique that allows a camera to rapidly acquire reflectance properties of objects from a single view-point, over relatively long distances and without encircling equipment. We measure material properties by indirectly illuminating an object by a laser source, and observing its reflected light indirectly using a time-of-flight camera. The configuration collectively acquires dense angular, but l...

  4. Single view reflectance capture using multiplexed scattering and time-of-flight imaging

    OpenAIRE

    Zhao, Shuang; Velten, Andreas; Raskar, Ramesh; Bala, Kavita; Naik, Nikhil Deepak

    2011-01-01

    This paper introduces the concept of time-of-flight reflectance estimation, and demonstrates a new technique that allows a camera to rapidly acquire reflectance properties of objects from a single view-point, over relatively long distances and without encircling equipment. We measure material properties by indirectly illuminating an object by a laser source, and observing its reflected light indirectly using a time-of-flight camera. The configuration collectively acquires dense angular, but l...

  5. Time-of-flight mass spectrographs—From ions to neutral atoms

    Science.gov (United States)

    Möbius, E.; Galvin, A. B.; Kistler, L. M.; Kucharek, H.; Popecki, M. A.

    2016-12-01

    After their introduction to space physics in the mid 1980s time-of-flight (TOF) spectrographs have become a main staple in spaceborne mass spectrometry. They have largely replaced magnetic spectrometers, except when extremely high mass resolution is required to identify complex molecules, for example, in the vicinity of comets or in planetary atmospheres. In combination with electrostatic analyzers and often solid state detectors, TOF spectrographs have become key instruments to diagnose space plasma velocity distributions, mass, and ionic charge composition. With a variety of implementation schemes that also include isochronous electric field configurations, TOF spectrographs can respond to diverse science requirements. This includes a wide range in mass resolution to allow the separation of medium heavy isotopes or to simply provide distributions of the major species, such as H, He, and O, to obtain information on source tracers or mass fluxes. With a top-hat analyzer at the front end, or in combination with deflectors for three-axis stabilized spacecraft, the distribution function of ions can be obtained with good time resolution. Most recently, the reach of TOF ion mass spectrographs has been extended to include energetic neutral atoms. After selecting the arrival direction with mechanical collimation, followed by conversion to ions, adapted TOF sensors form a new branch of the spectrograph family tree. We review the requirements, challenges, and implementation schemes for ion and neutral atom spectrographs, including potential directions for the future, while largely avoiding overlap with complementary contributions in this special issue.

  6. Characterisation of volatile components of Pinotage wines using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC–TOFMS)

    NARCIS (Netherlands)

    Weldegergis, B.T.; Villiers, de A.; McNeish, C.; Seethapathy, S.; Mostafa, A.; Górecki, T.; Crouch, A.M.

    2011-01-01

    As part of the ongoing research into the chemical composition of the uniquely South African wine cultivar Pinotage, the volatile composition of nine young wines of this cultivar was investigated using comprehensive two-dimensional gas chromatography (GC × GC) in combination with time-of-flight mass

  7. Characterisation of volatile components of Pinotage wines using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC–TOFMS)

    NARCIS (Netherlands)

    Weldegergis, B.T.; Villiers, de A.; McNeish, C.; Seethapathy, S.; Mostafa, A.; Górecki, T.; Crouch, A.M.

    2011-01-01

    As part of the ongoing research into the chemical composition of the uniquely South African wine cultivar Pinotage, the volatile composition of nine young wines of this cultivar was investigated using comprehensive two-dimensional gas chromatography (GC × GC) in combination with time-of-flight mass

  8. A high-resolution time-of-flight energy analyzer for femtosecond electron pulses at 30 keV

    Science.gov (United States)

    Gliserin, Alexander; Walbran, Matthew; Baum, Peter

    2016-03-01

    We report a time-of-flight spectrometer for electron pulses at up to 30 keV, which is a suitable energy for atomic-resolution femtosecond investigations via time-resolved electron diffraction, microscopy, and energy loss spectroscopy. For realistic femtosecond beams without apertures, the instrument's energy resolution is ˜0.5 eV (full width at half maximum) or 2 × 10-5 at a throughput of 50%-90%. We demonstrate the analyzer's versatility by three first applications, namely, femtosecond electron pulse metrology via optical streaking, in situ drift correction in laser-microwave synchronization for electron pulse compression, and time-resolved electron energy loss spectroscopy of aluminum, showing the instrument's capability of tracking plasmonic loss peak positions with few-meV accuracy.

  9. Results from the commissioning of a multi-modal endoscope for ultrasound and time of flight PET

    Energy Technology Data Exchange (ETDEWEB)

    Bugalho, Ricardo [LIP, Lisbon, (Portugal)

    2015-07-01

    The EndoTOFPET-US collaboration has developed a multi-modal imaging system combining Ultrasound with Time-of-Flight Positron Emission Tomography into an endoscopic imaging device. The objective of the project is to obtain a coincidence time resolution of about 200 ps FWHM and to achieve about 1 mm spatial resolution of the PET system, while integrating all the components in a very compact detector suitable for endoscopic use. This scanner aims to be exploited for diagnostic and surgical oncology, as well as being instrumental in the clinical test of new biomarkers especially targeted for prostate and pancreatic cancer. (authors)

  10. Time-of-flight imaging method to observe signatures of antiferromagnetically ordered states of fermionic atoms in an optical lattice.

    Science.gov (United States)

    Inaba, Kensuke; Yamashita, Makoto

    2010-10-22

    We propose a simple method to detect the antiferromagnetic (AF) state of fermionic atoms in an optical lattice by combining a time-of-flight (TOF) imaging method and a Feshbach resonance. In this scheme, the nontrivial dynamics of fermionic atoms during the imaging process works as a probe with respect to the breaking of the translational symmetry in the AF state. Precise numerical simulations demonstrate that the characteristic oscillatory dynamics induced by the scattering process that transfers an AF ordering vector appears in TOF images, which can be easily observed experimentally.

  11. A novel method for digital ultrasonic time-of-flight measurement.

    Science.gov (United States)

    Wang, X F; Tang, Z A

    2010-10-01

    Most ultrasonic ranging measurements are based on the determination of the ultrasonic time-of-flight (TOF). This paper develops a novel method for the TOF measurement which combines both the improved self-interference driving technique and the optional optimization signal processing algorithms. By stimulating the transmitter with the amplitude modulation and the phase modulation envelope square waveforms (APESWs), the proposed system can effectively reduce the errors caused by inertia delay and amplitude attenuation. In addition, based on different signal-to-noise ratio test conditions, the resultant received zero-crossing samples, which are deteriorated by noise, can be precisely inspected and calculated with two optimized algorithms named zero-crossing tracking (ZCT) and time-shifted superposition (TSS) method. The architecture of the designed system is divided into two parts. The novel APESW driving module, the received envelope zero-crossings phase detection module, and the ZCT method processing module are designed in a complex programmable logic device. The TSS signal processing module and the optimization algorithm discrimination program module are integrated in a digital signal processor. The TOF measurements calibrated in ultrasonic ranging experiments indicate that the relative errors of the method are limited in ±0.8%. Therefore, a feasible method is provided with the advantages of high noise immunity, accuracy, low cost, and ease of implementation.

  12. Repetitively sampled time-of-flight mass spectrometry for gas-phase kinetics studies

    Science.gov (United States)

    Fockenberg, Christopher; Bernstein, Herbert J.; Hall, Gregory E.; Muckerman, James T.; Preses, Jack M.; Sears, Trevor J.; Weston, Ralph E.

    1999-08-01

    An apparatus has been constructed to study radical-radical reactions in the gas phase. It consists of a tubular quartz reactor in which radicals are produced by flash photolysis using an excimer laser as light source. The composition of the gas mixture is analyzed in situ by photoionizing sampled gases using the vacuum ultraviolet emission of a hollow cathode lamp and subsequent time-of-flight mass spectrometry. A simple arrangement of grids at the entrance to the flight tube is used to interrupt the constant flux of ions by application of a combination of constant and pulsed voltages. Individual mass spectra can be taken at a repetition rate of around 20 kHz following each photolysis event. Signal counts from a specified number of consecutive mass spectra are fed into a 2 GHz multiscaler and accumulated as a sampling-time-indexed series of mass spectra. This allows simultaneous observation of the concentrations of multiple transient or stable species on a millisecond time scale. To achieve a suitable signal-to-noise ratio, signals were typically accumulated over several tens of thousands of laser shots at a pulse rate of 10-15 Hz.

  13. Continuously moving table time-of-flight angiography of the peripheral veins.

    Science.gov (United States)

    Huff, Sandra; Honal, Matthias; Baumann, Tobias; Hennig, Jürgen; Markl, Michael; Ludwig, Ute

    2010-05-01

    Time-of-flight (TOF) MR angiography allows for noninvasive vessel imaging. To overcome the limited volumetric coverage of standard TOF techniques, the aim of this study was to investigate the combination of TOF and continuously moving table (CMT) acquisitions for peripheral vein imaging based on image subtraction. Two acquisition strategies are presented: a simple two-step method based on 2-fold CMT acquisition and an advanced one-step method requiring only one continuous scan. Image quality of both CMT TOF techniques was evaluated by semiquantitative image grading and by signal-to-noise ratio and contrast-to-noise ratio analysis for veins of the upper and lower leg in 10 healthy volunteers. Results were compared to a standard stationary two-dimensional (2D) TOF multistation acquisition. Image grading revealed good image quality for both CMT TOF methods, thereby confirming the feasibility of axial 2D CMT TOF to assess the veins of the lower extremities during a single scan. Quantitative evaluation showed no significant difference in signal-to-noise ratio and contrast-to-noise ratio compared to the stationary experiment. Additional measurements in three patients with postthrombotic changes and varicosities demonstrated the clinical applicability of the presented methods. CMT TOF provides promising results and permits the detection of various pathologic changes of the venous system.

  14. Indirect time-of-flight 3D ranging based on SPADs

    Science.gov (United States)

    Bellisai, S.; Villa, F.; Tisa, S.; Bronzi, D.; Zappa, F.

    2012-01-01

    Systems for 3D image acquisition are the enabling technology for a number of applications such as architectural studies, safety and security, automotive. Single-sensor active-illumination cameras are the most promising system, ensuring a good depth measurement accuracy combined with a simple structure (no double sensor required), simplest measurement algorithm and night and daytime operation. These systems are based on the measurement of the time delay between the emission of light signal and the detection of the back-reflected signal (Time of Flight - TOF). The direct measurement of the time delay between two adjacent pulses is called direct TOF (dTOF), while if the time delay is obtained starting from the phase delay of a periodic waveform we speak of indirect TOF (iTOF). We present two different 0.35μm CMOS Silicon mini-arrays for iTOF 3D ranging based on square and sinusoidal waveforms, in which the sensitive element is a Single-Photon Avalanche Diode (SPAD).

  15. Highly miniaturized laser ablation time-of-flight mass spectrometer for a planetary rover

    Science.gov (United States)

    Rohner, Urs; Whitby, James A.; Wurz, Peter; Barabash, Stas

    2004-05-01

    We report the development and testing of a highly miniaturized mass spectrometer and ion source intended to be deployed on an airless planetary surface to measure the elemental and isotopic composition of solids, e.g., rocks and soils. Our design concentrates at this stage on the proposed BepiColombo mission to the planet Mercury. The mass analyzer is a novel combination of an electrostatic analyzer and a reflectron time-of-flight design. The ion source utilizes a laser induced plasma, which is directly coupled into the mass analyzer. Laser ablation gives high spatial resolution and avoids the need for sample preparation. Our prototype instrument has a demonstrated mass resolution m/Δm full width at half maximum in excess of 180 and a predicted dynamic range of better than five orders of magnitude. We estimate that a flight instrument would have a mass of 280 g (including laser and all electronics), a volume of 84 cm3, and could operate on 3 W power.

  16. Laser desorption time-of-flight mass spectrometry of vacuum UV photo-processed methanol ice

    Science.gov (United States)

    Paardekooper, D. M.; Bossa, J.-B.; Linnartz, H.

    2016-07-01

    Context. Methanol in the interstellar medium mainly forms upon sequential hydrogenation of solid CO. With typical abundances of up to 15% (with respect to water) it is an important constituent of interstellar ices where it is considered as a precursor in the formation of large and complex organic molecules (COMs), e.g. upon vacuum UV (VUV) photo-processing or exposure to cosmic rays. Aims: This study aims at detecting novel complex organic molecules formed during the VUV photo-processing of methanol ice in the laboratory using a technique more sensitive than regular surface diagnostic tools. In addition, the formation kinetics of the main photo-products of methanol are unravelled for an astronomically relevant temperature (20 K) and radiation dose. Methods: The VUV photo-processing of CH3OH ice is studied by applying laser desorption post-ionisation time-of-flight mass spectrometry (LDPI TOF-MS), and analysed by combining molecule-specific fragmentation and desorption features. Results: The mass spectra correspond to fragment ions originating from a number of previously recorded molecules and from new COMs, such as the series (CO)xH, with x = 3 and y prebiotic glycerin belongs. The formation of these large COMs has not been reported in earlier photolysis studies and suggests that such complex species may form in the solid state under interstellar conditions.

  17. 3D-guided CT reconstruction using time-of-flight camera

    Science.gov (United States)

    Ismail, Mahmoud; Taguchi, Katsuyuki; Xu, Jingyan; Tsui, Benjamin M. W.; Boctor, Emad M.

    2011-03-01

    We propose the use of a time-of-flight (TOF) camera to obtain the patient's body contour in 3D guided imaging reconstruction scheme in CT and C-arm imaging systems with truncated projection. In addition to pixel intensity, a TOF camera provides the 3D coordinates of each point in the captured scene with respect to the camera coordinates. Information from the TOF camera was used to obtain a digitized surface of the patient's body. The digitization points are transformed to X-Ray detector coordinates by registering the two coordinate systems. A set of points corresponding to the slice of interest are segmented to form a 2D contour of the body surface. Radon transform is applied to the contour to generate the 'trust region' for the projection data. The generated 'trust region' is integrated as an input to augment the projection data. It is used to estimate the truncated, unmeasured projections using linear interpolation. Finally the image is reconstructed using the combination of the estimated and the measured projection data. The proposed method is evaluated using a physical phantom. Projection data for the phantom were obtained using a C-arm system. Significant improvement in the reconstructed image quality near the truncation edges was observed using the proposed method as compared to that without truncation correction. This work shows that the proposed 3D guided CT image reconstruction using a TOF camera represents a feasible solution to the projection data truncation problem.

  18. Design of the TORCH detector: A Cherenkov based Time-of-Flight system for particle identification

    CERN Document Server

    AUTHOR|(CDS)2078663; Rademacker, Jonas

    The LHCb detector at the LHC collider has been very successfully operated over the past years, providing new and profound insights into the Standard Model, in particular through study of $b$-hadrons to achieve a better understanding of CP violation. One of the key components of LHCb is its particle identification system, comprised of two RICH detectors, which allow for high precision separation of particle species over a large momentum range. In order to retain and improve the performance of the particle identification system in light of the LHCb upgrade, the TORCH detector has been proposed to supplement the RICH system at low momentum (2-10 GeV/c). The TORCH detector provides (charged) particle identification through precision timing of particles passing through it. Assuming a known momentum from the tracking, it is possible to derive the species of a particle from the time of flight from its primary vertex. This measurement is achieved by timing and combining photons generated in a solid radiator. The geom...

  19. Data Collection and Processing Instrumentation for Time-of-Flight Mass Spectrometry and Ion Mobility Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Sysoev, Alexey A.; Fomin, O. I.; Poteshin, S. S.; Chernyshev, D. M.; Karpov, A. V.; Sysoev, Alexander A.

    Data processing characteristics can significantly affect reliability of obtained results. Here we discuss two recently developed data collection instruments based on analog-to-digital converters. The first instrument is based on three 500 MHz 12 bit ADC and used for extended dynamic range measurements. Based on 667 MHz 8 bit ADC the second one allows fast 3D data acquisition. The instruments were used for time-of-flight mass spectrometry and ion mobility TOF mass spectrometry fast data acquisition and processing.

  20. Assessing and minimizing contamination in time of flight based validation data

    Science.gov (United States)

    Lennox, Kristin P.; Rosenfield, Paul; Blair, Brenton; Kaplan, Alan; Ruz, Jaime; Glenn, Andrew; Wurtz, Ronald

    2017-10-01

    Time of flight experiments are the gold standard method for generating labeled training and testing data for the neutron/gamma pulse shape discrimination problem. As the popularity of supervised classification methods increases in this field, there will also be increasing reliance on time of flight data for algorithm development and evaluation. However, time of flight experiments are subject to various sources of contamination that lead to neutron and gamma pulses being mislabeled. Such labeling errors have a detrimental effect on classification algorithm training and testing, and should therefore be minimized. This paper presents a method for identifying minimally contaminated data sets from time of flight experiments and estimating the residual contamination rate. This method leverages statistical models describing neutron and gamma travel time distributions and is easily implemented using existing statistical software. The method produces a set of optimal intervals that balance the trade-off between interval size and nuisance particle contamination, and its use is demonstrated on a time of flight data set for Cf-252. The particular properties of the optimal intervals for the demonstration data are explored in detail.

  1. Visualization of acetaminophen-induced liver injury by time-of-flight secondary ion mass spectrometry.

    Science.gov (United States)

    Murayama, Yohei; Satoh, Shuya; Hashiguchi, Akinori; Yamazaki, Ken; Hashimoto, Hiroyuki; Sakamoto, Michiie

    2015-11-01

    Time-of-flight secondary ion mass spectrometry (MS) provides secondary ion images that reflect distributions of substances with sub-micrometer spatial resolution. To evaluate the use of time-of-flight secondary ion MS to capture subcellular chemical changes in a tissue specimen, we visualized cellular damage showing a three-zone distribution in mouse liver tissue injured by acetaminophen overdose. First, we selected two types of ion peaks related to the hepatocyte nucleus and cytoplasm using control mouse liver. Acetaminophen-overdosed mouse liver was then classified into three areas using the time-of-flight secondary ion MS image of the two types of peaks, which roughly corresponded to established histopathological features. The ion peaks related to the cytoplasm decreased as the injury became more severe, and their origin was assumed to be mostly glycogen based on comparison with periodic acid-Schiff staining images and reference compound spectra. This indicated that the time-of-flight secondary ion MS image of the acetaminophen-overdosed mouse liver represented the chemical changes mainly corresponding to glycogen depletion on a subcellular scale. In addition, this technique also provided information on lipid species related to the injury. These results suggest that time-of-flight secondary ion MS has potential utility in histopathological applications.

  2. Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, A. S., E-mail: Ajsen@fysik.dtu.dk; Salewski, M.; Korsholm, S. B.; Leipold, F.; Nielsen, S. K.; Rasmussen, J.; Stejner, M. [Association Euratom - DTU, Technical University of Denmark, Department of Physics, Kgs. Lyngby (Denmark); Eriksson, J.; Ericsson, G.; Hjalmarsson, A. [Association Euratom - VR, Uppsala University, Department of Physics and Astronomy, Uppsala (Sweden)

    2014-11-15

    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR.

  3. High speed simultaneous measurement of pulse area and time-of-flight for photomultiplier signals

    Energy Technology Data Exchange (ETDEWEB)

    Hartouni, E.P.; Jensen, D.A.; Klima, B.; Kreisler, M.N.; Lee, S.; Markianos, K.; Nordberg, M.; Rabin, M.S.Z.; Uribe, J.; Wesson, D. (Dept. of Physics and Astronomy, Univ. Massachusetts, Amherst, MA (United States)); Church, M.; Gara, A.; Gottschalk, E.; Hylton, R.; Knapp, B.C.; Sippach, W.; Stern, B.; Wiencke, L. (Columbia Univ., Nevis Lab., Irvington-on-Hudson, NY (United States)); Christian, D.; Etchegoyen, M.C.B.; Gutierrez, G.; Holmes, S.; Strait, J.; Wehmann, A. (Fermilab, Batavia, IL (United States)); Avilez, C.; Correa, W.; Felix, J.; Flores, H.; Moreno, G.; Romero, M.; Sosa, M. (Inst. de Fisica, Univ. Guanajuato, Leon (Mexico)); Forbush, M.; Huson, F.R.; White, J.T.; Wightman, J.A. (Dept. of Physics, Texas A and M Univ., TX (United States))

    1992-06-15

    A modular system to provide high speed simultaneous measurements of pulse area and time-of-flight for photomultiplier signals is described. By requiring a minimum pulse size and a time-of-flight signal within a gate before recording either measurement, the system achieves several advantages over other techniques. In particular, since no time is wasted reading channels without useful information, read out speed is enhanced. The system permits accurate measurements at rates exceeding 10 MHz per channel and can be read out without excessive dead time at rates up to approximately 100 kHz. Data storage problems are also reduced. Both pulse area and time-of-flight are measured using 128 bins (7 bits). Costs are less than 40 US Dollar per channel. Other advantages and design features are discussed. (orig.).

  4. Time-Of-Flight Camera, Optical Tracker and Computed Tomography in Pairwise Data Registration.

    Directory of Open Access Journals (Sweden)

    Bartlomiej Pycinski

    Full Text Available A growing number of medical applications, including minimal invasive surgery, depends on multi-modal or multi-sensors data processing. Fast and accurate 3D scene analysis, comprising data registration, seems to be crucial for the development of computer aided diagnosis and therapy. The advancement of surface tracking system based on optical trackers already plays an important role in surgical procedures planning. However, new modalities, like the time-of-flight (ToF sensors, widely explored in non-medical fields are powerful and have the potential to become a part of computer aided surgery set-up. Connection of different acquisition systems promises to provide a valuable support for operating room procedures. Therefore, the detailed analysis of the accuracy of such multi-sensors positioning systems is needed.We present the system combining pre-operative CT series with intra-operative ToF-sensor and optical tracker point clouds. The methodology contains: optical sensor set-up and the ToF-camera calibration procedures, data pre-processing algorithms, and registration technique. The data pre-processing yields a surface, in case of CT, and point clouds for ToF-sensor and marker-driven optical tracker representation of an object of interest. An applied registration technique is based on Iterative Closest Point algorithm.The experiments validate the registration of each pair of modalities/sensors involving phantoms of four various human organs in terms of Hausdorff distance and mean absolute distance metrics. The best surface alignment was obtained for CT and optical tracker combination, whereas the worst for experiments involving ToF-camera.The obtained accuracies encourage to further develop the multi-sensors systems. The presented substantive discussion concerning the system limitations and possible improvements mainly related to the depth information produced by the ToF-sensor is useful for computer aided surgery developers.

  5. Characterization of electron detectors by time-of-flight in neutron \\b{eta} decay experiments

    CERN Document Server

    Dubbers, Dirk

    2016-01-01

    Progress in neutron decay experiments requires better methods for the characterization of electron detectors. I show that for such \\b{eta}-decay studies, electron time-of-flight can be used for in-situ calibration of electron detectors. Energy resolution down to a few keV can be reached for the lower part of the electron spectrum in neutron decay, where conventional calibration methods come to their limit. Novel time-of-flight methods can also be used to perform a complete experiment on electron backscattering from their detectors.

  6. Time of flight estimation for breast cancer margin thickness using embedded tumors

    Science.gov (United States)

    Bowman, Tyler; El-Shenawee, Magda; Campbell, Lucas

    2016-03-01

    This work aims to enact a quick and reasonable estimation of breast cancer margin thickness using time of flight analysis of embedded breast cancer tissue. A pulsed terahertz system is used to obtain reflection imaging scans from breast cancer tumors that are formalin-fixed and embedded in paraffin blocks. Time of flight analysis is then used to compare the reflection patterns seen within the block to pathology sections and paraffin-embedded sections that are taken throughout the depth of the tumor in order to estimate the three-dimensional boundaries of the tumor.

  7. Design, construction, characterization and use of a detector to measure time of flight of cosmic rays

    Science.gov (United States)

    Araujo, A. C.; Félix, J.

    2016-10-01

    In the study of cosmic rays, measurements of time of flight and momentum have been used to identify incident particles from its physical properties, like mass. In this poster we present the design, construction, characterization, and operation of a detector to measure time of flight of cosmic rays. The device is comprised of three plates of plastic scintillator arranged in vertical straight line, they are coupled to one photomultiplier tube. The analogical output has been connected to a data acquisition system to obtain the number of digital pulses per millisecond. We present preliminary results.

  8. Ultrasonic Time of Flight Diffraction Technique for Weld Defects: A Review

    Directory of Open Access Journals (Sweden)

    K. Manjula

    2012-12-01

    Full Text Available To achieve the quality and safety in industrial applications, the damaged products must be detected. To do that NDT is used. In NDT, Ultrasonic Time-of-Flight Diffraction is a well-known technique for detecting the size and location of the defects. Nowadays the Time of Flight Diffraction (ToFD is used for inspecting the materials during production than that of radiography and other ultrasonic NDT procedures. ToFD technique can be used into many different ways. This study gives a review of various ultrasonic ToFD techniques for welding defects and aims at the usage of it.

  9. [Separation and identification of beta-casein from Chinese human milk by ion exchange chromatography-matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry].

    Science.gov (United States)

    Huang, Yu; Ren, Haowei; Liu, Biao; Liu, Ning; Li, Meng; Wang, Dongmao

    2013-05-01

    The selective precipitation of whole casein from skimmed milk was achieved by the addition of calcium salt under acidic pH. The effects of pH, centrifugal force and final concentration of CaCl2 on the separation of casein were studied by measuring the purity of final products using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The results showed that casein with the highest purity could be obtained with the pH of 4.3, the centrifugal force of 10 400 g and the final concentration of CaCl2 of 60 mmol/L. The casein was processed with DEAE anion exchange chromatography and three peaks were obtained. Then the third peak (peak III) was identified with Western-Blot method and matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS). The identification of Western-Blot showed that peak III can combine with the specificity of human milk beta-casein antibody, and it is proved to be human milk beta-casein. The fingerprints of peak III were nalyzed by Mascot searching, and the sequence coverage was 50%, further supporting it is human milk beta-casein. In conclusion, an effective method to obtain human milk beta-casein from milk samples through DEAE anion exchange chromatography was established, and it is suitable for the proteomics research requirements of the beta-casein from human milk.

  10. Subgap time of flight: A spectroscopic study of deep levels in semi-insulating CdTe:Cl

    Energy Technology Data Exchange (ETDEWEB)

    Pousset, J.; Farella, I.; Cola, A., E-mail: adriano.cola@le.imm.cnr.it [Institute for Microelectronics and Microsystems—Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Gambino, S. [Dipartimento di Matematica e Fisica “Ennio De Giorgi,” Università del Salento, Lecce I-73100 (Italy); CNR NANOTEC—Istituto di Nanotecnologia, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce (Italy)

    2016-03-14

    We report on a study of deep levels in semi-insulating CdTe:Cl by means of a time-of-flight spectral approach. By varying the wavelength of a pulsed optical source within the CdTe energy gap, transitions to/from localized levels generate free carriers which are analysed through the induced photocurrent transients. Both acceptor-like centers, related to the A-center, and a midgap level, 0.725 eV from the valence band, have been detected. The midgap level is close to the Fermi level and is possibly a recombination center responsible for the compensation mechanism. When the irradiance is varied, either linear or quadratic dependence of the electron and hole collected charge are observed, depending on the dominant optical transitions. The analysis discloses the potentiality of such a novel approach exploitable in the field of photorefractive materials as well as for deep levels spectroscopy.

  11. Time-of-flight secondary ion mass spectrometry study of lithium intercalation process in LiCoO2 thin film

    Science.gov (United States)

    Dellen, C.; Gehrke, H.-G.; Möller, S.; Tsai, C.-L.; Breuer, U.; Uhlenbruck, S.; Guillon, O.; Finsterbusch, M.; Bram, M.

    2016-07-01

    A detailed time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of the lithium de-/intercalation in thin films of the insertion cathode material lithium cobalt oxide is presented. The LiCoO2 (LCO) thin films are deposited by radio frequency magnetron sputtering at 600 °C, having a (003) preferred orientation after the deposition. The thin electrode films are cycled with liquid electrolyte against lithium metal, showing 80-86% extractable capacities. After disassembling the cells, the depth resolved elemental distribution in the LCO is investigated by ToF-SIMS and glow discharge optical emission spectroscopy. Both techniques show a stepwise lithium distribution in charged state, leading to a lithium depleted layer close to the surface. In combination with the electrochemical results, the qualitative comparison of the different lithium depth profiles yields a reversible lithium extraction in the depleted area below the stability limit for bulk materials of LCO. For bulk LCO, a phase change normally occurs when the lithium concentration in LixCoO2 is lower than x = 0.5. As a possible cause for the inhibition of the phase change, the preferred orientation and thus pinning of the crystal structure of the film by the substrate is proposed.

  12. Measurement and simulation of the response function of time of flight enhanced diagnostics neutron spectrometer for beam ion studies at EAST tokamak

    Science.gov (United States)

    Peng, X. Y.; Chen, Z. J.; Zhang, X.; Du, T. F.; Hu, Z. M.; Ge, L. J.; Zhang, Y. M.; Sun, J. Q.; Gorini, G.; Nocente, M.; Tardocchi, M.; Hu, L. Q.; Zhong, G. Q.; Pu, N.; Lin, S. Y.; Wan, B. N.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.

    2016-11-01

    The 2.5 MeV TOFED (Time-Of-Flight Enhanced Diagnostics) neutron spectrometer with a double-ring structure has been installed at Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas. This work describes the response function of the TOFED spectrometer, which is evaluated for the fully assembled instrument in its final layout. Results from Monte Carlo simulations and dedicated experiments with pulsed light sources are presented and used to determine properties of light transport from the scintillator. A GEANT4 model of the TOFED spectrometer was developed to calculate the instrument response matrix. The simulated TOFED response function was successfully benchmarked against measurements of the time-of-flight spectra for quasi-monoenergetic neutrons in the energy range of 1-4 MeV. The results are discussed in relation to the capability of TOFED to perform beam ion studies on EAST.

  13. A field-deployable, chemical ionization time-of-flight mass spectrometer

    Directory of Open Access Journals (Sweden)

    T. H. Bertram

    2011-07-01

    Full Text Available We constructed a new chemical ionization time-of-flight mass spectrometer (CI-TOFMS that measures atmospheric trace gases in real time with high sensitivity. We apply the technique to the measurement of formic acid via negative-ion proton transfer, using acetate as the reagent ion. A novel high pressure interface, incorporating two RF-only quadrupoles is used to efficiently focus ions through four stages of differential pumping before analysis with a compact TOFMS. The high ion-duty cycle (>20 % of the TOFMS combined with the efficient production and transmission of ions in the high pressure interface results in a highly sensitive (>300 ions s−1 pptv−1 formic acid instrument capable of measuring and saving complete mass spectra at rates faster than 10 Hz. We demonstrate the efficient transfer and detection of both bare ions and ion-molecule clusters, and characterize the instrument during field measurements aboard the R/V Atlantis as part of the CalNex campaign during the spring of 2010. The in-field short-term precision is better than 5 % at 1 pptv (pL/L, for 1-s averages. The detection limit (3 σ, 1-s averages of the current version of the CI-TOFMS, as applied to the in situ detection of formic acid, is limited by the magnitude and variability in the background determination and was determined to be 4 pptv. Application of the CI-TOFMS to the detection of other inorganic and organic acids, as well as the use of different reagent ion molecules (e.g. I, CF3O, CO3 is promising, as we have demonstrated efficient transmission and detection of both bare ions and their associated ion-molecule clusters.

  14. Determination of triacetone triperoxide using ultraviolet femtosecond multiphoton ionization time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ezoe, Ryota [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Imasaka, Tomoko [Laboratory of Chemistry, Graduate School of Design, Kyushu University, 4-9-1, Shiobaru, Minami-ku, Fukuoka 815-8540 (Japan); Imasaka, Totaro, E-mail: imasaka@cstf.kyushu-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Division of Optoelectronics and Photonics, Center for Future Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2015-01-01

    Highlights: • A UV ultrashort laser pulse was useful for ionization of triacetone triperoxide. • A molecular ion was strongly enhanced in multiphoton ionization mass spectrometry. • Triacetone triperoxide in the human blood was measured without any interferences. • An organic compound of phorone was formed in the human blood from acetone. - Abstract: Triacetone triperoxide (TATP), an explosive compound, was measured using gas chromatography combined with multiphoton ionization time-of-flight mass spectrometry (GC/MPI-TOFMS). By decreasing the pulse width of a femtosecond laser from 80 to 35 fs, a molecular ion was drastically enhanced and was measured as one of the major ions in the mass spectrum. The detection limits obtained using the molecular (M·{sup +}) and fragment (C{sub 2}H{sub 3}O{sup +}) ions were similar or slightly superior to those obtained using conventional mass spectrometry based on electron and chemical ionization. In order to improve the reliability, an isotope of TATP, i.e., TATP-d18, was synthesized and used as an internal standard in the trace analysis of TATP in a sample of human blood. TATP could be identified in a two-dimensional display, even though numerous interfering compounds were present in the sample. Acetone, which is frequently used as a solvent in sampling TATP, produced a chemical species with a retention time nearly identical to that of TATP and provided a C{sub 2}H{sub 3}O{sup +} fragment ion that was employed for measuring a chromatogram of TATP in conventional MS. This compound, the structure of which was assigned as phorone, was clearly differentiated from TATP based on a molecular ion observable in MPI-TOFMS.

  15. The diagnostic accuracy of time-of-flight MR angiography in diagnosing Moyamoya disease

    Energy Technology Data Exchange (ETDEWEB)

    Shono, Tadahisa; Ikezaki, Kiyonobu; Matsushima, Toshio; Inoue, Tooru; Fujii, Kiyotaka; Fukui, Masashi [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1995-09-01

    Conventional cerebral angiography is essential for achieving the diagnosis of Moyamoya disease. It is, however, an invasive examination, especially for the pediatric patients. In this paper, we report on the results of an investigation as to whether MRA is able to accurately visualize the steno-occlusive changes in the carotid fork and the basal moyamoya vessels less invasively. Twenty patients among them, 16 children who were diagnosed as having Moyamoya disease with conventional angiography underwent MRI and MRA using a 1.5T MR unit (Signa, G.E.). Angiographically, 37 sides were determined to be in stage 3. MRA was performed using two-dimensional time-of-flight (2D-TOF), 3D-TOF, and gadolinium (Gd)-enhanced 3D-TOF methods. The 3D-TOF MRAs showed almost equal sensitivity to that of conventional angiography for the detection of steno-occlusive changes in the carotid fork. However, it was difficult to visualize the moyamoya vessels clearly. Further, 3D-TOF, 2D-TOF, and Gd-enhanced 3D-TOF methods depicted the moyamoya vessels in 65%, 79%, and 80% of the examined sides, respectively. In contrast, MRI visualized the moyamoya vessels as multiple flow voids in the basal ganglia in 38 of 40 sides (95%). Based on the above findings, it was thus concluded that approximately 90% of the stage 3 Moyamoya disease cases could be diagnosed by a combination of 3D-TOF MRA and MRI without the use of conventional angiography. (author).

  16. Precise Time-of-Flight Calculation For 3-D Synthetic Aperture Focusing

    DEFF Research Database (Denmark)

    Andresen, Henrik; Nikolov, Svetoslav; Jensen, Jørgen Arendt

    2009-01-01

    , because of a lack of a simple expression for the exact time of flight (ToF). This paper presents a new method for calculating the ToF for a 3D case in a single step using a linear array. This method is more flexible than the previously proposed method and is able to beamform a fewer number of points much...

  17. Calibration of a neutron time-of-flight multidetector system for an intensity interferometry experiment

    NARCIS (Netherlands)

    Ghetti, R; Colonna, N; Helgesson, J; Avdeichikov, [No Value; Golubev, P; Jakobsson, B; Tagliente, G; Brandenburg, S; Kravchuk, VL; Wilschut, HW; Kopecky, S; Anderson, EW; Nadel-Turonski, P; Westerberg, L; Bellini, [No Value; Sperduto, ML; Sutera, C

    2004-01-01

    We present the details of an experiment on light particle interferometry. In particular, we focus on a time-of-flight technique which uses a cyclotron RF signal as a start and a liquid scintillator time signal as a stop, to measure neutron energy in the range of En approximate to 1.8-150 MeV. This d

  18. A fast preamplifier concept for SiPM-based time-of-flight PET detectors

    NARCIS (Netherlands)

    Huizenga, J.; Seifert, S.; Schreuder, F.; Dendooven, P.; Löhner, H.; Vinke, R.; Schaart, D. R.; van Dam, H.T.

    2012-01-01

    Silicon photomultipliers (SiPMs) offer high gain and fast response to light, making them interesting for fast timing applications such as time-of-flight (TOF) PET. To fully exploit the potential of these photosensors, dedicated preamplifiers that do not deteriorate the rise time and signal-to-noise

  19. Efficient and Fast Implementation of Embedded Time-of-Flight Ranging System Based on FPGAs

    DEFF Research Database (Denmark)

    Zhou, Weiguo; Lyu, Congyi; Jiang, Xin

    2017-01-01

    Time-of-flight cameras perceive depth information about the surrounding environment with an amplitude-modulated near-infrared light source. The distance between the sensor and objects is calculated through measuring the time the light needs to travel. To be used in fast and embedded applications...

  20. Environmental Effects on Measurement Uncertainties of Time-of-Flight Cameras

    DEFF Research Database (Denmark)

    Gudmundsson, Sigurjon Arni; Aanæs, Henrik; Larsen, Rasmus

    2007-01-01

    In this paper the effect the environment has on the SwissRanger SR3000 Time-Of-Flight camera is investigated. The accuracy of this camera is highly affected by the scene it is pointed at: Such as the reflective properties, color and gloss. Also the complexity of the scene has considerable effects...

  1. Grasping objects from a user’s hand using time-of-flight camera data

    CSIR Research Space (South Africa)

    Govender, N

    2010-11-01

    Full Text Available . This paper presents a system which allows a robotic arm manipulator to grasp any moving object from a user’s hand and releases the object when indicated to do so. Data from a Time-of-Flight camera is fused with an ordinary laboratory camera to create a robust...

  2. Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors - Particle Detectors and Detector Systems

    CERN Document Server

    Ullaland, O

    2011-01-01

    Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors in 'Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '3.3 Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.3 Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors 3.3.1 Introduction 3.3.2 Time of Flight Measurements 3.3.2.1 Scintillator hodoscopes 3.3.2.2 Parallel plate ToF detectors 3.3.3 Cherenkov Radiation 3.3.3.1 ...

  3. Four-Spot Time-Of-Flight Laser Anemometer For Turbomachinery

    Science.gov (United States)

    Wernet, Mark P.; Skoch, Gary J.

    1995-01-01

    Two-color, four-spot time-of-flight laser anemometer designed for measuring flow velocity within narrow confines of small centrifugal compressor. Apparatus well suited for measuring fast (typical speeds 160 to 700 m/s), highly turbulent gas flows in turbomachinery. Other potential applications include measurement of gas flows in pipelines and in flows from explosions.

  4. Identification of Bacteria Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

    Science.gov (United States)

    Kedney, Mollie G.; Strunk, Kevin B.; Giaquinto, Lisa M.; Wagner, Jennifer A.; Pollack, Sidney; Patton, Walter A.

    2007-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS or simply MALDI) has become ubiquitous in the identification and analysis of biomacromolecules. As a technique that allows for the molecular weight determination of otherwise nonvolatile molecules, MALDI has had a profound impact in the molecular…

  5. Time-of-Flight Measurement of the Speed of Sound in a Metal Bar

    Science.gov (United States)

    Ganci, Salvatore

    2016-01-01

    A simple setup was designed for a "time-of-flight" measurement of the sound speed in a metal bar. The experiment requires low cost components and is very simple to understand by students. A good use of it is as a demonstration experiment.

  6. Time-of-Flight Measurement of the Speed of Sound in Water

    Science.gov (United States)

    Ganci, Salvatore

    2016-01-01

    A simple setup is designed to investigate a "time-of-flight" measurement of the speed of sound in water. This experiment only requires low cost components and is also very simple to understand by students. It could be easily used as a demonstration experiment.

  7. Analysis of gait using a treadmill and a Time-of-flight camera

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Paulsen, Rasmus Reinhold; Larsen, Rasmus

    2009-01-01

    We present a system that analyzes human gait using a treadmill and a Time-of-flight camera. The camera provides spatial data with local intensity measures of the scene, and data are collected over several gait cycles. These data are then used to model and analyze the gait. For each frame...

  8. EDEN - A NEUTRON TIME-OF-FLIGHT MULTIDETECTOR FOR DECAY STUDIES OF GIANT STATES

    NARCIS (Netherlands)

    LAURENT, H; LEFORT, H; BEAUMEL, D; BLUMENFELD, Y; FORTIER, S; GALES, S; GUILLOT, J; ROYNETTE, JC; VOLKOV, P; BRANDENBURG, S

    1993-01-01

    A neutron time-of-flight multidetector has been built to study the decay of giant states. It is made of 40 individual detectors. A liquid scintillator is used for neutron-gamma-ray pulse shape discrimination. The overall efficiency of the multidetector (epsilonOMEGA/4pi) is 1% for 6 MeV neutrons and

  9. Time of flight assisted ΔE - E method for enhanced isotope separation capabilities in heavy ion elastic recoil detection analysis

    Science.gov (United States)

    Eschbaumer, S.; Bergmaier, A.; Seiler, D.; Dollinger, G.

    2017-09-01

    The time of flight energy (TOF-E) setup installed at the scattering chamber of the Q3D magnetic spectrograph to perform heavy ion elastic recoil detection (ERD) analysis at the 14 MV Munich Tandem Accelerator has recently been upgraded. Now, the energy detector of the TOF-E setup is additionally capable of performing ΔE - E measurements for high energy recoil ions obtained from e.g. a 170 MeV 127 I projectile beam. Time of flight information is simultaneously acquired with the ΔE - E data for each detected ion. The combination of the TOF-E and the ΔE - E data gives the opportunity to set effective filter conditions to select for both, the elemental and the mass of the detected ion. As an example a boron doped carbon layer is analyzed and 10B and 11B is separated with the help of the combination of both methods.

  10. The online chemical analysis of single particles using aerosol beams and time of flight mass spectroscopy

    NARCIS (Netherlands)

    Kievit, O.; Weiss, M.; Verheijen, P.J.T.; Marijnissen, J.C.M.; Scarlett, B.

    This paper describes an on-line instrument, capable of measuring the size and chemical composition of single aerosol particles. Possible applications include monitoring aerosol reactors and studying atmospheric chemistry. The main conclusion is that a working prototype has been built and tested. It

  11. Sputtering of alkali halides studied by a mass selected time of flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Postawa, Z.; Czuba, P.; Poradzisz, A.; Szymonski, M. (Uniwersytet Jagiellonski, Cracow (Poland). Inst. Fizyki)

    1989-01-01

    Energy distributions of alkali and halogen atoms sputtered with a low-energy electron beam have been measured for NaCl, CsI and KBr single crystals. Energy spectra for alkali atoms can be described by the Maxwell-Boltzmann distribution. In case of halogen atoms, for some crystals, an additional, non-thermal component appears. The behaviour of this component was investigated as a function of the target temperature, the beam energy, its current density and the ejection angle. The results can be described by creation of focused replacement sequences and H-centre migration model. The ejection of non-thermal halogen atoms from the (100) surface of KBr single crystal is strongly forward peaked along the normal. This effect is caused by a thin damage layer appearing on the surface due to a strong nonstoichiometry of the erosion process itself. (author).

  12. Urinary metabonomics of stomach cancer assessed by rapid resolution liquid chromatography/time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; REN Hui; JIANG Yang; GAO Yu-fei; LIU Shu-ying

    2013-01-01

    Background Stomach cancer is among the most commonly occurring malignancies worldwide.It would be beneficial to develop a urine-based assay whereby patients with undiagnosed stomach cancer could be screened and their cancer detected in the earliest stages.Methods A urinary metabonomics method based on ultra-performance liquid chromatography combined with quadruple time-of-flight mass spectrometry was used to analyze urine samples from patients with stomach cancer and healthy controls.Results Statistical analysis revealed a clear separation of patients and healthy controls using the aforementioned methodology.Some significantly changed metabolites were identified.Conclusions Use of the metabonomics method in patients with stomach cancer could effectively detect distinct changes in urinary metabolites and had the capacity to detect cancer; therefore,it may be a valuable tool in earlier diagnosis.Furthermore,the detection and identification of altered metabolites in the current study may help elucidate possible mechanisms involved in stomach cancer.

  13. Time-of-flight measurements in atomic beam devices using adiabatic high frequency transitions and sextupole magnets

    CERN Document Server

    Baumgarten, C; Brunn, I; Court, G; Ciullo, G; Ferretti, P; Golendukhin, A; Graw, G; Haeberli, W; Henoch, M; Hertenberger, R; Koch, N; Kolster, H; Lenisa, P; Nass, A; Podyachev, S P; Reggiani, D; Rith, K; Simani, M C; Steffens, E; Stewart, J; Wise, T

    2002-01-01

    Atomic beam devices are frequently equipped with sextupole magnets to focus the beam or to act as spin filters in combination with RF-transitions for manipulating the hyperfine population within the atomic beam. A useful tool for the analysis of sextupole systems, the application of time-of-flight (TOF) measurements is presented. TOF measurements are enabled without mechanical beam chopper by utilizing adiabatic radio frequency transitions to select atoms within a certain time interval. This method is especially interesting for the use in atomic beam devices that are already equipped with RF-transitions and sextupole magnets and where space limitations or the required quality of the vacuum do not allow the installation of a mechanical chopper. The measurements presented here were performed with the atomic beam polarimeter of the HERMES polarized deuterium target and the results have been used to optimize the sextupole system of the polarimeter.

  14. Neutron capture cross section measurement of 151Sm at the CERN neutron time of flight facility (n_TOF).

    Science.gov (United States)

    Abbondanno, U; Aerts, G; Alvarez-Velarde, F; Alvarez-Pol, H; Andriamonje, S; Andrzejewski, J; Badurek, G; Baumann, P; Becvár, F; Benlliure, J; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Cennini, P; Chepel, V; Chiaveri, E; Colonna, N; Cortes, G; Cortina, D; Couture, A; Cox, J; Dababneh, S; Dahlfors, M; David, S; Dolfini, R; Domingo-Pardo, C; Duran, I; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Frais-Koelbl, H; Furman, W; Goncalves, I; Gallino, R; Gonzalez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Isaev, S; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Kerveno, M; Ketlerov, V; Koehler, P; Konovalov, V; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martinez-Val, J; Mastinu, P; Mengoni, A; Milazzo, P M; Molina-Coballes, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papaevangelou, T; Paradela, C; Pavlik, A; Pavlopoulos, P; Perlado, J M; Perrot, L; Pignatari, M; Plag, R; Plompen, A; Plukis, A; Poch, A; Policarpo, A; Pretel, C; Quesada, J; Raman, S; Rapp, W; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Soares, J C; Stephan, C; Tagliente, G; Tain, J; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Voss, F; Wendler, H; Wiescher, M; Wisshak, K

    2004-10-15

    The151Sm(n,gamma)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of kT=30 keV the Maxwellian averaged cross section of this unstable isotope (t(1/2)=93 yr) was determined to be 3100+/-160 mb, significantly larger than theoretical predictions.

  15. Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis.

    Science.gov (United States)

    Pozo, Oscar J; Van Eenoo, Peter; Deventer, Koen; Elbardissy, Hisham; Grimalt, Susana; Sancho, Juan V; Hernandez, Felix; Ventura, Rosa; Delbeke, Frans T

    2011-01-17

    Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated. QqQ allowed for the detection of all analytes at the minimum required performance limit (MRPL) established by the World Anti-Doping Agency (between 2 and 10 ng mL(-1) in urine). TOF and QTOF approaches were not sensitive enough to detect some of the analytes (3'-hydroxy-stanozolol or the metabolites of boldenone and formebolone) at the established MRPL. Although a suitable accuracy was obtained, the precision was unsatisfactory (RSD typically higher than 20%) for quantitative purposes irrespective of the analyser used. The methods were applied to 30 real samples declared positives either for the misuse of boldenone, stanozolol and/or methandienone. Most of the compounds were detected by every technique, however QqQ was necessary for the detection of some metabolites in a few samples. Finally, the possibility to detect non-target steroids has been explored by the use of TOF and QTOF. The use of this approach revealed that the presence of boldenone and its metabolite in one sample was due to the intake of androsta-1,4,6-triene-3,17-dione. Additionally, the intake of methandienone was confirmed by the post-target detection of a long-term metabolite.

  16. Time of flight in MUSE at PIM1 at Paul Scherrer Institute

    Science.gov (United States)

    Lin, Wan; Gilman, Ronald; MUSE Collaboration

    2016-09-01

    The MUSE experiment at PIM1 at Paul Scherrer Institute in Villigen, Switzerland, measures elastic scattering of electrons and muons from a liquid hydrogen target. The intent of the experiment is to deduce whether the radius of the proton is the same when determined from the two different particle types. Precision timing is an important aspect of the experiment, used to determine particle types, reaction types, and beam momentum. Here we present results for a test setup measuring time of flight between prototypes of two detector systems to be used in the experiment, compared to Geant4 simulations. The results demonstrate time of flight resolution better than 100 ps, and beam momentum determination at the level of a few tenths of a percent. Douglass Project for Rutgers Women in Math, Science & Engineering, National Science Foundation Grant 1306126 to Rutgers University.

  17. Neutron Time-of-Flight Quantification of Water Desorption Isotherms of Montmorillonite

    DEFF Research Database (Denmark)

    Gates, Will P.; Bordallo, Heloisa N.; Aldridge, Laurence P.

    2012-01-01

    enabled us to differentiate at least two water motions during dehydration of Ca- and Na-SAz-1 (initially equilibrated at RH = 55%) by using a "controlled water loss" time-of-flight procedure. This work confirms that (a) interlayer and cationic water in dioctahedral smectites are characterized by slower......The multiple energy states of water held by surfaces of a clay mineral can be effectively probed with time-of-flight and fixed elastic window neutron scattering. We used these techniques to quantitatively differentiate water types, including rotational and translational diffusions, in Ca- and Na...... motions than interparticle water, (b) interlayer cations influenced the dynamics of water loss, probably through its affect on clay fabric, and (c) interparticle water behaves more like bulk water. At 55% RH the Ca montmorillonite held more interparticle water, but on dehydration under controlled...

  18. Time of flight and range of the motion of a projectile in a constant gravitational field

    Directory of Open Access Journals (Sweden)

    P. A. Karkantzakos

    2009-01-01

    Full Text Available In this paper we study the classical problem of the motion of a projectile in a constant gravitational field under the influenceof a retarding force proportional to the velocity. Specifically, we express the time of flight, the time of fall and the range ofthe motion as a function of the constant of resistance per unit mass of the projectile. We also prove that the time of fall isgreater than the time of rise with the exception of the case of zero constant of resistance where we have equality. Finally weprove a formula from which we can compute the constant of resistance per unit mass of the projectile from time of flight andrange of the motion when the acceleration due to gravity and the initial velocity of the projectile are known.

  19. Plane-parallel chamber as detector for time-of-flight measurements

    CERN Document Server

    Akimov, V A; Boyarinov, S V

    2002-01-01

    To arrange time-of-flight measurements in terms of the ALICE experiment one designed a system of gas detectors to record minimal-ionizing particles (MIP). Detector system is based on a plane-parallel gas-filled chamber (PPC) operating under gas intensification avalanche-type regime. One presents the results of simulation of gas discharge in PPC and evaluates the accuracy of measurement of MIP time-of-flight. One analyzes the test results of performances of PPC of various dimensions and with working gas medium various compositions. One detected correlation of flight time and of signal amplitude of PPC. One stresses, as well, positive effect of admission of electronegative additions into gas mixture. PPC time resolution constitutes 200-250 ps and MIP recording efficiency - exactly 70-90%

  20. Implementation of spatial touch system using time-of-flight camera

    Institute of Scientific and Technical Information of China (English)

    AHN Yang-Keun; PARK Young-Choong; CHOI Kwang-Soon; PARK Woo-Choo; SEO Hae-Moon; JUNG Kwang-Mo

    2009-01-01

    Recently developed time-of-flight principle based depth-sensing video camera technologies provide precise per-pixel range data in addition to color video. Such cameras will find application in robotics and vision-based human computer interaction scenarios such as games and gesture input systems. Time-of-flight principle range cameras are becoming more and more available. They promise to make the 3D reconstruction of scenes easier, avoiding the practical issues resulting from 3D imaging techniques based on triangulation or disparity estimation. A spatial touch system was presented which uses a depth-sensing camera to touch spatial objects and details on its implementation, and how this technology will enable new spatial interactions was speculated.

  1. A new type of detector time of flight - multi-gap resistive plate chamber

    CERN Document Server

    Chen, H; Eppley, G; Geurts, F J M; Huang, S; Li, C; Liu, H; Llope, W J; Ruan, L; Shao, M; Wang, X L; Wang, Z; Wu, J; Xu, Z; Zhang, Z

    2004-01-01

    Multi-gap resistive plate chamber is a new detector technology. It was first developed by the LHC-ALICE group at CERN in the late 1990s. The MRPC is a ideal detector for time-of-flight measurement due to its small gaps and works in the proportional (avalanche) mode. The beam test of single module result shows that MRPC tuning resolution is better than 70ps and the detection efficiency is higher than 95%. It is also radiation hard. A time-of-flight tray with 28 on MRPC modules. was tested at AGS. The average timing resolution is about 75ps (including the 4cm of beam spread) and detection efficiency is better than 95%. This tray has been installed on STAR detector system in October 2002 and used on the 200GeV d+Au experiment.

  2. Development of a high resolution laser based angle-resolving time-of-flight photoelectron spectrometer

    CERN Document Server

    Berntsen, M H; Tjernberg, O

    2011-01-01

    We present the design and performance of a novel Laser-based Angle-Resolving Time-of-Flight (LARTOF) system for photoemission from solids in the vacuum ultraviolet (VUV) energy range. A pulsed laser provides photons which through a third harmonic generation (THG) process performed in a xenon filled gas cell generates VUV photons of energy 10.5 eV. The time-of-flight analyzer is able to collect all electrons that are emitted from the sample within a circular cone of up to +/-15 degrees. By simultaneously measuring the energy and emission angle along two spatial directions for the electrons the analyzer provides three-dimensional detection capability. Data from a test measurement performed on the Au(111) surface state is presented along with some more advanced measurements of the Fermi surface of the high-temperature superconductor Bi2212.

  3. TOF-VIS, software for interactive exploration of time-of-flight data

    Science.gov (United States)

    Mikkelson, D.; Worlton, T.

    TOF-VIS is a fast, highly interactive program for examining time-of-flight neutron-scattering data. All spectra from an experiment are displayed simultaneously as an image. The data can be displayed in terms of time-of-flight, energy, wave vector, or lattice spacing. TOF-VIS has been used for examining data from IPNS and ISIS, and has been useful for diagnosing problems with instruments and detectors as well as for making a quick evaluation of the quality of the data. Hard copy output to a variety of devices using routines built on PGPLOT is now available. TOF-VIS is portable to VMS and UNIX, and is currently implemented primarily using object-based methods in C, MOTIF and X-windows.

  4. Isobaric Identification Using Gas-Filled Time-of-Flight Measurements in an Accelerator Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-Jing; RUAN Xiang-Dong; HE Ming; WANG Hui-Juan; LI Guo-Qiang; WU Shao-Yong; DONG Ke-Jun; LIN Min; JIANG Shan

    2005-01-01

    @@ A gas-filled time-of-flight (GF-TOF) detector has been built and developed to improve the ability of isobaric identification in accelerator mass spectrometry (AMS) measurements, and a time resolution (without gas filled)of better than 350ps is achieved. The GF-TOF detector is tested by means of measuring a standard AgCl(36Cl/Cl = 7.6 × 10-9g/g) sample with the 36Cl ion energy of 64, 49 and 33MeV, respectively. 36Cl and 36S particles were successfully separated in the TOF spectra output from the GF-TOF detector. The comparison between the gas-filled time-of-flight method and the △E - E method is described. Some results relative to the GF-TOF method are given as well.

  5. Mobile high-resolution time-of-flight mass spectrometer for in-situ analytics

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Johannes; Ebert, Jens [II. Physikalisches Institut, JLU, Giessen (Germany); Dickel, Timo; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [II. Physikalisches Institut, JLU, Giessen (Germany); GSI, Darmstadt (Germany)

    2011-07-01

    A compact multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been developed. For the first time it allows for mass measurements with a resolving power exceeding 100000 and sub ppm accuracy in a mobile device. Thus it allows to resolve isobars and enables to accurately determine the composition and structure of biomolecules. The MR-TOF-MS consists of an atmospheric pressure interface for DESI and REIMS, ion cooler, ion trap, time-of-flight analyzer, MCP detector and DAQ. Vacuum system components, power supplies as well as electronics are mounted together with the ion optical spectrometer parts on a single frame with a total volume of 0.8 m{sup 3}. Applications of the device within the AmbiProbe research program include in-situ mass spectrometry such as real-time tissue recognition in electrosurgery, identification of mycotoxins and analysis of soil samples for environmental studies.

  6. Time-of-flight measurement with femtosecond pulses for high precision ranging lidar

    Science.gov (United States)

    Lee, J.; Kim, Y.-J.; Lee, K.; Lee, S.; Kim, S.-W.

    2010-10-01

    The time-of-flight of light pulses has long been used as a direct measure of distance, but the state-of-the-art measurement precision using conventional light pulses or microwaves reaches only several hundreds of micromeres. This is due to the bandwidth limit of the photodetectors available today, which is in the picosecond range at best. Here, we improve the time-of-flight precision to the nanometer regime by timing femtosecond pulses through phase-locking control of the pulse repetition rate using the optical cross-correlation technique that exploits a second-harmonic birefringence crystal and a balance photodetector. The enhanced capability is maintained at long range without periodic ambiguity, being well suited to terrestrial lidar applications such as geodetic surveying, range finders and absolute altimeters. This method could also be applied to future space missions of formation-flying satellites for synthetic aperture imaging and remote experiments related to the general relativity theory.

  7. Computational imaging with multi-camera time-of-flight systems

    KAUST Repository

    Shrestha, Shikhar

    2016-07-11

    Depth cameras are a ubiquitous technology used in a wide range of applications, including robotic and machine vision, human computer interaction, autonomous vehicles as well as augmented and virtual reality. In this paper, we explore the design and applications of phased multi-camera time-of-flight (ToF) systems. We develop a reproducible hardware system that allows for the exposure times and waveforms of up to three cameras to be synchronized. Using this system, we analyze waveform interference between multiple light sources in ToF applications and propose simple solutions to this problem. Building on the concept of orthogonal frequency design, we demonstrate state-of-the-art results for instantaneous radial velocity capture via Doppler time-of-flight imaging and we explore new directions for optically probing global illumination, for example by de-scattering dynamic scenes and by non-line-of-sight motion detection via frequency gating. © 2016 ACM.

  8. Analysis, Modeling and Dynamic Optimization of 3D Time-of-Flight Imaging Systems

    OpenAIRE

    Schmidt, Mirko

    2011-01-01

    The present thesis is concerned with the optimization of 3D Time-of-Flight (ToF) imaging systems. These novel cameras determine range images by actively illuminating a scene and measuring the time until the backscattered light is detected. Depth maps are constructed from multiple raw images. Usually two of such raw images are acquired simultaneously using special correlating sensors. This thesis covers four main contributions: A physical sensor model is presented which enables the analysis a...

  9. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    OpenAIRE

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF...

  10. A Differential Time-of-flight Spectrometer of Very Slow Neutrons

    CERN Document Server

    Pokotilovski, Yu N; Geltenbort, P; Brenner, Th

    2011-01-01

    A time-of-flight spectrometer of neutrons in the energy range (0.05 -- 2.5)$\\mu$eV is described. This spectrometer has been tested my measuring the total and differential neutron cross sections for a number of materials: Al, Cu, $^{6}$LiF, Si, Zr, teflon, polyethylene and liquid fluoropolymers, that are essential for experiments in the physics of ultracold neutrons.

  11. Accurate Mass Determination of Amino Alcohols by Turboionspray/Time-of-Flight Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    GENG,Yu(耿昱); GUO,Yin-Long(郭寅龙); ZHAO,Shi-Min(赵士民); MA,Sheng-Ming(麻生明)

    2002-01-01

    Amino alcohols were studied by turboionspray/time-of-flight mass spectrometry (TIS/TOF-MS) with the aim of determining the accurate mass of their protonated molecule ions.Polyethylene glycol (PEG) was used as the internal reference.Compared with the theoretical values, all relative errors were less than 5×10-6. The effects of nozzle potential, nozzle temperature, acquisition rate etc. on accurate mass determination were also studied.

  12. Parameters’ Covariance in Neutron Time of Flight Analysis – Explicit Formulae

    Energy Technology Data Exchange (ETDEWEB)

    Odyniec, M. [NSTec; Blair, J. [NSTec

    2014-12-01

    We present here a method that estimates the parameters’ variance in a parametric model for neutron time of flight (NToF). The analytical formulae for parameter variances, obtained independently of calculation of parameter values from measured data, express the variances in terms of the choice, settings, and placement of the detector and the oscilloscope. Consequently, the method can serve as a tool in planning a measurement setup.

  13. The multigap resistive plate chamber as a time-of-flight detector

    CERN Document Server

    Akindinov, A; Basile, M; Cerron-Zeballos, E; Cifarelli, Luisa; Cindolo, F; Choi, J; Cozzoni, B; De Caro, A; De Pasquale, S; Kim, D W; Kim, N Y; Klempt, W; Kluge, A; Laurenti, G; Lee, S C; Golovine, V; Hatzifotiadou, D; Martemyanov, A N; Martinengo, P; Pesci, A; Platner, E D; Roberts, J; Seganti, A; Semak, A A; Smirnitsky, A V; Spegel, M; Szymanski, P; Valenti, G; Vicinanza, D; Williams, M C S; Zichichi, A

    2000-01-01

    The goal of this R&D has been to reach the time resolution needed for time-of-flight detectors using the Multigap Resistive Plate Chamber (MRPC). We present here a MRPC with a time resolution of 70 ps. This prototype has been studied within the R&D program for the very large area TOF array of the ALICE experiment at the CERN LHC. (5 refs).

  14. Neutron xyz - polarization analysis at a time-of-flight instrument

    Energy Technology Data Exchange (ETDEWEB)

    Ehlers, Georg [ORNL; Stewart, John Ross [ISIS Facility, Rutherford Appleton Laboratory; Andersen, Ken [ESS

    2015-01-01

    When implementing a dedicated polarization analysis setup at a neutron time-of-flight instrument with a large area detector, one faces enormous challenges. Nevertheless, significant progress has been made towards this goal over the last few years. This paper addresses systematic limitations of the traditional method that is used to make these measurements, and a possible strategy to overcome these limitations. This will be important, for diffraction as well as inelastic experiments, where the scattering occurs mostly out-of-plane.

  15. Fast and Practical Head Tracking in Brain Imaging with Time-of-Flight Camera

    DEFF Research Database (Denmark)

    Wilm, Jakob; Olesen, Oline Vinter; Jensen, Rasmus Ramsbøl

    2013-01-01

    This paper investigates the potential use of Time-of-Flight cameras (TOF) for motion correction in medical brain scans. TOF cameras have previously been used for tracking purposes, but recent progress in TOF technology has made it relevant for high speed optical tracking in high resolution medica...... of expensive triangulation and surface reconstruction. Tracking experiments with a motion controlled head phantom were performed with a translational tracking error below 2mm and a rotational tracking error below 0.5°....

  16. A compact time-of-flight spectrometer for electrofission studiesrefid="FN1">*

    Science.gov (United States)

    Heil, R. D.; Drexler, J.; Huber, K.; Kneissl, U.; Mank, G.; Ries, H.; Ströher, H.; Weber, T.; Wilke, W.

    1985-09-01

    A compact time-of-flight spectrometer for measurements of fission fragment distributions is described. The start detector consists of a channel plate arrangement with an electrostatic mirror. The time resolution of PPACs, serving as stop detectors, has been optimized. Velocity distributions of 252Cf fragments and mean velocities are reported. The results are discussed with respect to planned (e, e'f) coincidence experiments at the Mainz microtron.

  17. A position-sensitive time-of-flight analyser for study of molecular photofragmentation

    CERN Document Server

    Rius-I-Riu, J; Karawajczyk, A; Winiarczyk, P

    2002-01-01

    The basic features of a simple radial position-sensitive detector design, construction and performance, are described in detail in this paper. The electronics and method used to correlate the position information from the spectrum recorded by the detector are presented. Monte Carlo simulations of the performance of the detector embedded in a time of flight analyser show that such an instrument enables kinetic energy and angular distribution measurements and triple coincidence studies of photofragmentation of simple molecules.

  18. Implementation of a new type of time-of-flight laser anemometer.

    Science.gov (United States)

    Wernet, M P; Edwards, R V

    1986-03-01

    A new time-of-flight (TOF) laser anemometer system utilizing a spatial lead-lag filter for bipolar pulse generation has been constructed and tested. This new TOF has been modified to enable measurements in turbulent flows near walls. Good results have been obtained as close as 100 microm from a surface, with a 140-mm focal length final lens. Lading's theory for the behavior of the measurement variance has been confirmed for this configuration.

  19. The CDFII Time-Of-Flight Detector and Impact on Beauty Flavor Tagging

    OpenAIRE

    2002-01-01

    The new CDFII detector incorporates a Time-of-Flight detector (TOF), employing plastic scintillator bars and fine-mesh photomultipliers. Since August 2001 the TOF system has been fully instrumented and integrated into the CDFII data acquisition system. With a design goal of $100 ps$ resolution the TOF system will provide at least two standard deviations separation between $K^{\\pm}$ and $\\pi^{\\pm}$ for momenta $p

  20. Single photon detection based devices and techniques for pulsed time-of-flight applications

    OpenAIRE

    Hallman, L. (Lauri)

    2015-01-01

    Abstract In this thesis, a new type of laser diode transmitter using enhanced gain-switching suitable for use with a single photon avalanche diode (SPAD) detector was developed and tested in the pulsed time-of-flight laser range finding (lidar) application. Several laser diode versions were tested and the driving electronics were developed. The driving electronics improvements enabled a pulsing frequency of up to 1 MHz, while the maximum laser output power was about 5–40 W depending on...

  1. Timing performances of a data acquisition system for Time of Flight PET

    Energy Technology Data Exchange (ETDEWEB)

    Morrocchi, Matteo, E-mail: matteo.morrocchi@pi.infn.it [University of Pisa and INFN Sezione di Pisa, I 56127 Pisa (Italy); Marcatili, Sara; Belcari, Nicola; Bisogni, Maria G. [University of Pisa and INFN Sezione di Pisa, I 56127 Pisa (Italy); Collazuol, Gianmaria [University of Padova and INFN Sezione di Padova (Italy); Ambrosi, Giovanni [INFN Sezione di Perugia, I 06100 Perugia (Italy); Corsi, Francesco; Foresta, Maurizio; Marzocca, Cristoforo; Matarrese, Gianvito [Politecnico di Bari and INFN Sezione di Bari, I 70100 Bari (Italy); Sportelli, Giancarlo; Guerra, Pedro; Santos, Andres [Universidad Politecnica de Madrid, E 28040 Madrid (Spain); Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Del Guerra, Alberto [University of Pisa and INFN Sezione di Pisa, I 56127 Pisa (Italy)

    2012-12-11

    We are investigating the performances of a data acquisition system for Time of Flight PET, based on LYSO crystal slabs and 64 channels Silicon Photomultipliers matrices (1.2 cm{sup 2} of active area each). Measurements have been performed to test the timing capability of the detection system (SiPM matices coupled to a LYSO slab and the read-out electronics) with both test signal and radioactive source.

  2. Detecting correlation functions of ultracold atoms through fourier sampling of time-of-flight images.

    Science.gov (United States)

    Duan, L-M

    2006-03-17

    We propose a detection method for ultracold atoms which allows reconstruction of the full one-particle and two-particle correlation functions from the measurements. The method is based on Fourier sampling of the time-of-flight images through two consecutive impulsive Raman pulses. For applications of this method, we discuss a few examples, including detection of phase separation between superfluid and Mott insulators, various types of spin or superfluid orders, entanglement, exotic or fluctuating orders.

  3. 应用高效液相色谱-四极杆飞行时间高分辨质谱联用技术研究部分水解蛋白婴幼儿奶粉中的标记物%Research on the biomarkers in partially hydrolyzed protein infant milk combined by high performance liquid chromatography-Q-time of flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    吴映璇; 林峰; 欧阳少伦; 廖玮玲; 邵琳智; 邹游; 杜志峰

    2015-01-01

    目的:比较部分水解蛋白的婴幼儿奶粉和普通婴幼儿奶粉的指纹图谱,寻找具有潜在甄别意义的标记物,以利于有效区分含有部分水解蛋白的婴幼儿奶粉和普通婴幼儿奶粉。方法采用高效液相色谱-四极杆飞行时间高分辨质谱(HPLC-Q-TOF-MS)联用技术,对1个含水解蛋白的婴幼儿奶粉和17个普通婴幼儿奶粉进行分析,将获得的指纹图谱,用计算机软件进行比较分析,寻找特征标记物。再采用液质联用技术,对验证样品进行特征标记物的可靠性验证。结果部分水解蛋白的婴幼儿奶粉和普通婴幼儿奶粉共有36个成分有统计意义,从中筛选出2个成分进行验证,从部分水解蛋白婴幼儿奶粉的验证样品中均可发现,普通婴幼儿奶粉均未发现。结论应用HPLC-Q-TOF-MS联用技术作为研究含部分水解蛋白婴幼儿奶粉中标识成份的工具,具有较好的重复性与精度,筛选得到的2个成分均有可能是潜在的部分水解蛋白婴幼儿奶粉标记物。%Objective To compare partially hydrolyzed protein infant milk powder with ordinary infant milk powder, and explore potential biomarkers in fingerprint to effectively distinguish between two groups. Methods One partially hydrolyzed protein infant and 17 ordinary infant milk powders were analyzed by high performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry method (HPLC-Q-TOF-MS), the fingerprints were compared with computer software in order to explore characteristic markers and verified the reliability of tracking samples by liquid chromatography-mass spectrometry techniques. Results Thirty-six kinds of component in samples might be potential biomarkers between partially hydrolyzed protein infant milk powder and ordinary infant milk powder, 2 kinds of them were selected for verification. As the result, the tracking sample of partially hydrolyzed protein infant milk could be found

  4. Nanometer scale elemental analysis in the helium ion microscope using time of flight spectrometry.

    Science.gov (United States)

    Klingner, N; Heller, R; Hlawacek, G; von Borany, J; Notte, J; Huang, J; Facsko, S

    2016-03-01

    Time of flight backscattering spectrometry (ToF-BS) was successfully implemented in a helium ion microscope (HIM). Its integration introduces the ability to perform laterally resolved elemental analysis as well as elemental depth profiling on the nm scale. A lateral resolution of ≤54nm and a time resolution of Δt≤17ns(Δt/t≤5.4%) are achieved. By using the energy of the backscattered particles for contrast generation, we introduce a new imaging method to the HIM allowing direct elemental mapping as well as local spectrometry. In addition laterally resolved time of flight secondary ion mass spectrometry (ToF-SIMS) can be performed with the same setup. Time of flight is implemented by pulsing the primary ion beam. This is achieved in a cost effective and minimal invasive way that does not influence the high resolution capabilities of the microscope when operating in standard secondary electron (SE) imaging mode. This technique can thus be easily adapted to existing devices. The particular implementation of ToF-BS and ToF-SIMS techniques are described, results are presented and advantages, difficulties and limitations of this new techniques are discussed.

  5. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Andersen, Thomas; Jensen, Robert; Christensen, M. K.

    2012-01-01

    response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m∕Δm > 2500. The system design...

  6. BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET

    Science.gov (United States)

    Brunner, S. E.; Schaart, D. R.

    2017-06-01

    Due to detector developments in the last decade, the time-of-flight (TOF) method is now commonly used to improve the quality of positron emission tomography (PET) images. Clinical TOF-PET systems based on L(Y)SO:Ce crystals and silicon photomultipliers (SiPMs) with coincidence resolving times (CRT) between 325 ps and 400 ps FWHM have recently been developed. Before the introduction of L(Y)SO:Ce, BGO was used in many PET systems. In addition to a lower price, BGO offers a superior attenuation coefficient and a higher photoelectric fraction than L(Y)SO:Ce. However, BGO is generally considered an inferior TOF-PET scintillator. In recent years, TOF-PET detectors based on the Cherenkov effect have been proposed. However, the low Cherenkov photon yield in the order of  ˜10 photons per event complicates energy discrimination-a severe disadvantage in clinical PET. The optical characteristics of BGO, in particular its high transparency down to 310 nm and its high refractive index of  ˜2.15, are expected to make it a good Cherenkov radiator. Here, we study the feasibility of combining event timing based on Cherenkov emission with energy discrimination based on scintillation in BGO, as a potential approach towards a cost-effective TOF-PET detector. Rise time measurements were performed using a time-correlated single photon counting (TCSPC) setup implemented on a digital photon counter (DPC) array, revealing a prompt luminescent component likely to be due to Cherenkov emission. Coincidence timing measurements were performed using BGO crystals with a cross-section of 3 mm  ×  3 mm and five different lengths between 3 mm and 20 mm, coupled to DPC arrays. Non-Gaussian coincidence spectra with a FWHM of 200 ps were obtained with the 27 mm3 BGO cubes, while FWHM values as good as 330 ps were achieved with the 20 mm long crystals. The FWHM value was found to improve with decreasing temperature, while the FWTM value showed the opposite trend.

  7. Fourier rebinning and consistency equations for time-of-flight PET planograms

    Science.gov (United States)

    Li, Yusheng; Defrise, Michel; Matej, Samuel; Metzler, Scott D.

    2016-09-01

    Due to the unique geometry, dual-panel PET scanners have many advantages in dedicated breast imaging and on-board imaging applications since the compact scanners can be combined with other imaging and treatment modalities. The major challenges of dual-panel PET imaging are the limited-angle problem and data truncation, which can cause artifacts due to incomplete data sampling. The time-of-flight (TOF) information can be a promising solution to reduce these artifacts. The TOF planogram is the native data format for dual-panel TOF PET scanners, and the non-TOF planogram is the 3D extension of linogram. The TOF planograms is five-dimensional while the objects are three-dimensional, and there are two degrees of redundancy. In this paper, we derive consistency equations and Fourier-based rebinning algorithms to provide a complete understanding of the rich structure of the fully 3D TOF planograms. We first derive two consistency equations and John’s equation for 3D TOF planograms. By taking the Fourier transforms, we obtain two Fourier consistency equations (FCEs) and the Fourier-John equation (FJE), which are the duals of the consistency equations and John’s equation, respectively. We then solve the FCEs and FJE using the method of characteristics. The two degrees of entangled redundancy of the 3D TOF data can be explicitly elicited and exploited by the solutions along the characteristic curves. As the special cases of the general solutions, we obtain Fourier rebinning and consistency equations (FORCEs), and thus we obtain a complete scheme to convert among different types of PET planograms: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF planograms. The FORCEs can be used as Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. As a byproduct, we show the two consistency equations are necessary and sufficient for 3D TOF planograms. Finally, we give numerical

  8. Fourier rebinning and consistency equations for time-of-flight PET planograms.

    Science.gov (United States)

    Li, Yusheng; Defrise, Michel; Matej, Samuel; Metzler, Scott D

    2016-01-01

    Due to the unique geometry, dual-panel PET scanners have many advantages in dedicated breast imaging and on-board imaging applications since the compact scanners can be combined with other imaging and treatment modalities. The major challenges of dual-panel PET imaging are the limited-angle problem and data truncation, which can cause artifacts due to incomplete data sampling. The time-of-flight (TOF) information can be a promising solution to reduce these artifacts. The TOF planogram is the native data format for dual-panel TOF PET scanners, and the non-TOF planogram is the 3D extension of linogram. The TOF planograms is five-dimensional while the objects are three-dimensional, and there are two degrees of redundancy. In this paper, we derive consistency equations and Fourier-based rebinning algorithms to provide a complete understanding of the rich structure of the fully 3D TOF planograms. We first derive two consistency equations and John's equation for 3D TOF planograms. By taking the Fourier transforms, we obtain two Fourier consistency equations and the Fourier-John equation, which are the duals of the consistency equations and John's equation, respectively. We then solve the Fourier consistency equations and Fourier-John equation using the method of characteristics. The two degrees of entangled redundancy of the 3D TOF data can be explicitly elicited and exploited by the solutions along the characteristic curves. As the special cases of the general solutions, we obtain Fourier rebinning and consistency equations (FORCEs), and thus we obtain a complete scheme to convert among different types of PET planograms: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF planograms. The FORCEs can be used as Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. As a byproduct, we show the two consistency equations are necessary and sufficient for 3D TOF planograms

  9. A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products

    CERN Document Server

    Kuznetsov, A V; Westerberg, L; Lyapin, V G; Aleklett, K; Loveland, W; Bondorf, J P; Jakobsson, B; Whitlow, H J; El-Bouanani, M

    2000-01-01

    A compact Ultra-High Vacuum (UHV) compatible instrument for time of flight-energy measurements of slow heavy reaction products from nuclear reactions has been designed and tested at the CELSIUS storage ring in Uppsala. The construction is based on MicroChannel Plate (MCP) time detectors of the electron mirror type and silicon p-i-n diodes, and permits the detectors to be stacked side-by-side to achieve large solid angle coverage. This kind of telescope measures the Time of Flight (ToF) and Energy (E) of the particle from which one can reconstruct mass. The combination of an ultra-thin cluster gas-jet target and thin carbon emitter foils allows one to measure heavy residues down to an energy of approx 35 keV/nucleon from the interactions of 400 MeV/nucleon sup 1 sup 6 O with sup n sup a sup t Xe gas targets.

  10. A magnetic particle time-of-flight (MagPTOF) diagnostic for measurements of shock- and compression-bang time at the NIF (invited).

    Science.gov (United States)

    Rinderknecht, H G; Sio, H; Frenje, J A; Magoon, J; Agliata, A; Shoup, M; Ayers, S; Bailey, C G; Gatu Johnson, M; Zylstra, A B; Sinenian, N; Rosenberg, M J; Li, C K; Sèguin, F H; Petrasso, R D; Rygg, J R; Kimbrough, J R; Mackinnon, A; Bell, P; Bionta, R; Clancy, T; Zacharias, R; House, A; Döppner, T; Park, H S; LePape, S; Landen, O; Meezan, N; Robey, H; Glebov, V U; Hohenberger, M; Stoeckl, C; Sangster, T C; Li, C; Parat, J; Olson, R; Kline, J; Kilkenny, J

    2014-11-01

    A magnetic particle time-of-flight (MagPTOF) diagnostic has been designed to measure shock- and compression-bang time using D(3)He-fusion protons and DD-fusion neutrons, respectively, at the National Ignition Facility (NIF). This capability, in combination with shock-burn weighted areal density measurements, will significantly constrain the modeling of the implosion dynamics. This design is an upgrade to the existing particle time-of-flight (pTOF) diagnostic, which records bang times using DD or DT neutrons with an accuracy better than ±70 ps [H. G. Rinderknecht et al., Rev. Sci. Instrum. 83, 10D902 (2012)]. The inclusion of a deflecting magnet will increase D(3)He-proton signal-to-background by a factor of 1000, allowing for the first time simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions at the NIF.

  11. A magnetic particle time-of-flight (MagPTOF) diagnostic for measurements of shock- and compression-bang time at the NIF (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Rinderknecht, H. G., E-mail: hgr@mit.edu; Sio, H.; Frenje, J. A.; Gatu Johnson, M.; Zylstra, A. B.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Sèguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Magoon, J.; Agliata, A.; Shoup, M.; Glebov, V. U.; Hohenberger, M.; Stoeckl, C.; Sangster, T. C. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Ayers, S.; Bailey, C. G.; Rygg, J. R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2014-11-15

    A magnetic particle time-of-flight (MagPTOF) diagnostic has been designed to measure shock- and compression-bang time using D{sup 3}He-fusion protons and DD-fusion neutrons, respectively, at the National Ignition Facility (NIF). This capability, in combination with shock-burn weighted areal density measurements, will significantly constrain the modeling of the implosion dynamics. This design is an upgrade to the existing particle time-of-flight (pTOF) diagnostic, which records bang times using DD or DT neutrons with an accuracy better than ±70 ps [H. G. Rinderknecht et al., Rev. Sci. Instrum. 83, 10D902 (2012)]. The inclusion of a deflecting magnet will increase D{sup 3}He-proton signal-to-background by a factor of 1000, allowing for the first time simultaneous measurements of shock- and compression-bang times in D{sup 3}He-filled surrogate implosions at the NIF.

  12. Qualitative Characterization of the Aqueous Fraction from Hydrothermal Liquefaction of Algae Using 2D Gas Chromatography with Time-of-flight Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Maddi, Balakrishna; Panisko, Ellen; Albrecht, Karl; Howe, Daniel

    2016-01-01

    Two-dimensional gas chromatography coupled with time of flight mass spectrometry is a powerful tool for identifying and quantifying components in complex mixtures. It has been used to analyze gasoline, jet fuel, diesel, bio-diesel and organic fraction of bio-crude/bio-oil. In these experiments, the first dimension of separation was non-polar, followed by a polar separation. Aqueous fractions of bio-crude and other aqueous samples have been examined with similar column combinations. However, sample preparation techniques such as derivatization, solvent extraction, and solid-phase extraction were necessary prior to analysis. In this study, aqueous fraction obtained from hydrothermal liquefaction of algae was characterized by two-dimensional gas chromatography coupled with time of flight mass spectrometry without prior sample preparation techniques using a polar separation in the first dimension followed by a non-polar separation. Two-dimensional plots from this analysis were compared with those obtained from the more traditional column combination. Results from qualitative characterization aqueous fractions of algal bio-crude are discussed in detail. The advantages of using a polar separation followed by a non-polar separation for characterization of organics in aqueous samples by two-dimensional gas chromatography coupled with time of flight mass spectrometry are highlighted.

  13. (A new time of flight) Acoustic flow meter using wide band signals and adaptive beamforming techniques

    Science.gov (United States)

    Murgan, I.; Ioana, C.; Candel, I.; Anghel, A.; Ballester, J. L.; Reeb, B.; Combes, G.

    2016-11-01

    In this paper we present the result of our research concerning the improvement of acoustic time of flight flow metering for water pipes. Current flow meters are based on the estimation of direct time of flight by matched filtering of the received and emitted signals by acoustic transducers. Currently, narrow band signals are used, as well as a single emitter/receptor transducer configuration. Although simple, this configuration presents a series of limitations such as energy losses due to pipe wall/water interface, pressure/flow transients, sensitivity to flow induced vibrations, acoustic beam deformations and shift due to changes in flow velocity and embedded turbulence in the flow. The errors associated with these limitations reduce the overall robustness of existing flow meters, as well as the measured flow rate range and lower accuracy. In order to overcome these limitations, two major innovations were implemented at the signal processing level. The first one concerns the use of wide band signals that optimise the power transfer throughout the acoustic path and also increase the number of velocity/flow readings per second. Using wide band signals having a high duration-bandwidth product increases the precision in terms of time of flight measurements and, in the same time, improves the system robustness. The second contribution consists in the use of a multiple emitter - multiple receivers configuration (for one path) in order to compensate the emitted acoustic beam shift, compensate the time of flight estimation errors and thus increase the flow meter's robustness in case of undesired effects such as the “flow blow” and transient/rapid flow rate/velocity changes. Using a new signal processing algorithm that take advantage of the controlled wide band content coming from multiple receivers, the new flow meters achieves a higher accuracy in terms of flow velocity over a wider velocity range than existing systems. Tests carried out on real scale experimental

  14. IR-MALDI-LDI combined with ion mobility orthogonal time-of-flight mass spectrometry.

    Science.gov (United States)

    Woods, Amina S; Ugarov, Michael; Jackson, Shelley N; Egan, Thomas; Wang, Hay-Yan J; Murray, Kermit K; Schultz, J Albert

    2006-06-01

    Most MALDI instrumentation uses UV lasers. We have designed a MALDI-IM-oTOF-MS which employs both a Nd:YAG laser pumped optical parametric oscillator (OPOTEK, lambda = 2.8-3.2 microm at 20 Hz) to perform IR-LDI or IR-MALDI and a Nd:YLF laser (Crystalaser, lambda = 249 nm at 200 Hz) for the UV. Ion mobility (IM) gives a fast separation and analysis of biomolecules from complex mixtures in which ions of similar chemical type fall along well-defined "trend lines". Our data shows that ion mobility allows multiply charged monomers and multimers to be resolved; thus, yielding pure spectra of the singly charged protein ion which are virtually devoid of chemical noise. In addition, we have demonstrated that IR-LDI produced similar results as IR-MALDI for the direct tissue analysis of phospholipids from rat brain.

  15. GEANT4 simulation and evaluation of a time-of-flight spectrometer for nuclear cross section measurements in particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gruenwald, Oxana

    2011-06-08

    In 2007 a new project has been launched in a cooperation between the RWTH Aachen Physics Department, the University Hospital Aachen and the Philips Research Laboratories. The project aim is to validate and improve GEANT4 nuclear interaction models for use in proton and ion therapy. The method chosen here is the measurement of nuclear reaction cross sections which will not only provide a comparison to the simulation but will also allow to improve some of the parameters in the nuclear models. In the first phase of the project 200 MeV protons are used as a projectile in combination with a thin graphite target. For use in particle therapy the excitation functions of the most frequently produced isotopes need to be measured with an accuracy of 10% or less. For this purpose a dedicated detector system has been designed and implemented in GEANT4. The detection of target fragments produced by protons in graphite is achieved via time-of-flight spectrometry. In the setup presented here the primary beam first hits the Start detector and initiates the time-of-flight measurement before it passes through the apertures of two Veto detectors and impinges on the target. Successively, the secondary particles emanating from the target travel a short distance of 70/80 cm through vacuum (0.1 mbar) before they hit one of the 20 Stop detectors which end the time-of-flight measurement and record the energy deposited by the particle. The dissertation at hand describes the underlying detector concept and presents a detailed GEANT4 simulation of the setup which allows to evaluate the detector performance with respect to target fragment identification at a projectile energy of 200 MeV. At first, correlations of time-of-flight and energy deposition are built from simulated data and are subsequently used to reconstruct mass spectra of the detected fragments. Such influences on the detection performance as the target thickness, the residual pressure within the detector chamber, the Veto system

  16. Characterization of biomass burning emissions from cooking fires, peat, crop residue, and other fuels with high-resolution proton-transfer-reaction time-of-flight mass spectrometry

    Science.gov (United States)

    Stockwell, C. E.; Veres, P. R.; Williams, J.; Yokelson, R. J.

    2015-01-01

    We deployed a high-resolution proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) to measure biomass-burning emissions from peat, crop residue, cooking fires, and many other fire types during the fourth Fire Lab at Missoula Experiment (FLAME-4) laboratory campaign. A combination of gas standard calibrations and composition sensitive, mass-dependent calibration curves was applied to quantify gas-phase non-methane organic compounds (NMOCs) observed in the complex mixture of fire emissions. We used several approaches to assign the best identities to most major "exact masses", including many high molecular mass species. Using these methods, approximately 80-96% of the total NMOC mass detected by the PTR-TOF-MS and Fourier transform infrared (FTIR) spectroscopy was positively or tentatively identified for major fuel types. We report data for many rarely measured or previously unmeasured emissions in several compound classes including aromatic hydrocarbons, phenolic compounds, and furans; many of these are suspected secondary organic aerosol precursors. A large set of new emission factors (EFs) for a range of globally significant biomass fuels is presented. Measurements show that oxygenated NMOCs accounted for the largest fraction of emissions of all compound classes. In a brief study of various traditional and advanced cooking methods, the EFs for these emissions groups were greatest for open three-stone cooking in comparison to their more advanced counterparts. Several little-studied nitrogen-containing organic compounds were detected from many fuel types, that together accounted for 0.1-8.7% of the fuel nitrogen, and some may play a role in new particle formation.

  17. Combined Reversed Phase HPLC, Mass Spectrometry, and NMR Spectroscopy for a Fast Separation and Efficient Identification of Phosphatidylcholines

    Directory of Open Access Journals (Sweden)

    Jan Willmann

    2011-01-01

    Full Text Available In respect of the manifold involvement of lipids in biochemical processes, the analysis of intact and underivatised lipids of body fluids as well as cell and tissue extracts is still a challenging task, if detailed molecular information is required. Therefore, the advantage of combined use of high-pressure liquid chromatography (HPLC, mass spectrometry (MS, and nuclear magnetic resonance (NMR spectroscopy will be shown analyzing three different types of extracts of the ubiquitous membrane component phosphatidylcholine. At first, different reversed phase modifications were tested on phosphatidylcholines (PC with the same effective carbon number (ECN for their applicability in lipid analysis. The results were taken to improve the separation of three natural PC extract types and a new reversed phase (RP-HPLC method was developed. The individual species were characterized by one- and two-dimensional NMR and positive or negative ion mode quadrupole time of flight (q-TOF-MS as well as MS/MS techniques. Furthermore, ion suppression effects during electrospray ionisation (ESI, difficulties, limits, and advantages of the individual analytical techniques are addressed.

  18. Fully automatic and precise data analysis developed for time-of-flight mass spectrometry.

    Science.gov (United States)

    Meyer, Stefan; Riedo, Andreas; Neuland, Maike B; Tulej, Marek; Wurz, Peter

    2017-09-01

    Scientific objectives of current and future space missions are focused on the investigation of the origin and evolution of the solar system with the particular emphasis on habitability and signatures of past and present life. For in situ measurements of the chemical composition of solid samples on planetary surfaces, the neutral atmospheric gas and the thermal plasma of planetary atmospheres, the application of mass spectrometers making use of time-of-flight mass analysers is a technique widely used. However, such investigations imply measurements with good statistics and, thus, a large amount of data to be analysed. Therefore, faster and especially robust automated data analysis with enhanced accuracy is required. In this contribution, an automatic data analysis software, which allows fast and precise quantitative data analysis of time-of-flight mass spectrometric data, is presented and discussed in detail. A crucial part of this software is a robust and fast peak finding algorithm with a consecutive numerical integration method allowing precise data analysis. We tested our analysis software with data from different time-of-flight mass spectrometers and different measurement campaigns thereof. The quantitative analysis of isotopes, using automatic data analysis, yields results with an accuracy of isotope ratios up to 100 ppm for a signal-to-noise ratio (SNR) of 10(4) . We show that the accuracy of isotope ratios is in fact proportional to SNR(-1) . Furthermore, we observe that the accuracy of isotope ratios is inversely proportional to the mass resolution. Additionally, we show that the accuracy of isotope ratios is depending on the sample width Ts by Ts(0.5) . Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Use of a large time-compensated scintillation detector in neutron time-of-flight measurements

    Science.gov (United States)

    Goodman, Charles D.

    1979-01-01

    A scintillator for neutron time-of-flight measurements is positioned at a desired angle with respect to the neutron beam, and as a function of the energy thereof, such that the sum of the transit times of the neutrons and photons in the scintillator are substantially independent of the points of scintillations within the scintillator. Extrapolated zero timing is employed rather than the usual constant fraction timing. As a result, a substantially larger scintillator can be employed that substantially increases the data rate and shortens the experiment time.

  20. The time-of-flight method for characterizing the neutron response of liquid organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Iwanowska, J., E-mail: joanna.iwanowska@ncbj.gov.pl [National Centre for Nuclear Research, 05-400 Otwock-Swierk (Poland); Swiderski, L.; Krakowski, T.; Moszynski, M.; Szczesniak, T. [National Centre for Nuclear Research, 05-400 Otwock-Swierk (Poland); Pausch, G. [OncoRay—National Center for Radiation Research in Oncology, Fetscherstr. 74, PF 41, 01307 Dresden (Germany)

    2015-05-01

    The purpose of this work is to present a measurement method for determining the neutron responses of various liquid organic scintillators using a time-of-flight technique in conjunction with a D–T neutron generator. The method is based on fast-neutron scattering on protons in a liquid-scintillator medium and on the acquisition of the neutron response of the medium as a function of the proton-recoil energy. This method can be applied to all scintillators that utilize fast-neutron elastic scattering.

  1. SOI pixel circuits with synchronized TMC for time-of-flight stigmatic imaging mass spectrometry

    CERN Document Server

    Watanabe, Kaori; Fujita, Youichi; Arai, Yasuo; Hazama, Hisanao

    2015-01-01

    We propose SOI pixel circuits with a synchronized time memory cell (TMC) for time-of-flight stigmatic imaging mass spectrometry. The circuits simultaneously detect the position and the fine/coarse flight time of an ion for the MALDI-ToF mass spectrometer. We discuss the circuit design and present the simulation results of a prototype detector comprised of a 32 x 32 pixel array in which each pixel pitch is 40 um and the time resolution is a minimum of 1 ns. The results of transient analysis demonstrate the fully correct synchronous operation at a 100-MHz clock frequency and simultaneous 32-word SRAM writing.

  2. Time of Flight Analysis Using Cosmic Ray Muons in the ATLAS Tile Calorimeter

    CERN Document Server

    Meirose, B

    2007-01-01

    Using cosmic ray muon data recorded during the summer of 2007, we have studied the time-of-flight distributions between back-to-back modules of the ATLAS Tile Calorimeter. The results are in good agreement with the distributions expected from calorimeter geometry, and allow for cross-checks of timing corrections obtained in laser runs. Calorimeter timing is a useful tool to remove non-physics backgrounds, and we introduce new cuts at the cell level which improve the signal-to-noise ratio.

  3. Measure Fly off Velocity of the Ion by Time of Flight Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Primary detector is the charge collector, i.e. Faraday cup to measure fly off velocity of the ion by time of flight method. It is simple and applied set up,When it irradiates on the solid plane targets that laser beam of high power is focused, a thin layer of the high temperature and tight density plasma is produced on the target surface. As this plasma expands in the vacuum, it has of its energy in from of directed kinetic energy of the ion. The ion current signals observed by the charge collector at a large distance will correspond to high

  4. Delayed extraction time-of-flight mass spectrometer with electron impact for PAH studies

    Science.gov (United States)

    Najeeb, P. K.; Kadhane, U.

    2017-03-01

    A time-of-flight (ToF) mass spectrometer with a pulsed electron beam as well as pulsed extraction of the recoil ions, with variable delay is reported. The effectiveness of this technique is highlighted by studying the statistical decay of mono-cations over microsecond time scales. Various details of the design and operation are discussed in the context of electron impact ionization and fragmentation of naphthalene (C10H8). The temporal behavior of acetylene (C2H2) and diacetylene (C4H2) loss is observed and compared with the associated Arrhenius decay constant, internal energy and plasmon excitation energy.

  5. Testing a new NIF neutron time-of-flight detector with a bibenzyl scintillator on OMEGA.

    Science.gov (United States)

    Glebov, V Yu; Forrest, C; Knauer, J P; Pruyne, A; Romanofsky, M; Sangster, T C; Shoup, M J; Stoeckl, C; Caggiano, J A; Carman, M L; Clancy, T J; Hatarik, R; McNaney, J; Zaitseva, N P

    2012-10-01

    A new neutron time-of-flight (nTOF) detector with a bibenzyl crystal as a scintillator has been designed and manufactured for the National Ignition Facility (NIF). This detector will replace a nTOF20-Spec detector with an oxygenated xylene scintillator currently operational on the NIF to improve the areal-density measurements. In addition to areal density, the bibenzyl detector will measure the D-D and D-T neutron yield and the ion temperature of indirect- and direct-drive-implosion experiments. The design of the bibenzyl detector and results of tests on the OMEGA Laser System are presented.

  6. Analysis of ion dynamics and peak shapes for delayed extraction time-of-flight mass spectrometers

    Science.gov (United States)

    Collado, V. M.; Ponciano, C. R.; Fernandez-Lima, F. A.; da Silveira, E. F.

    2004-06-01

    The dependence of time-of-flight (TOF) peak shapes on time-dependent extraction electric fields is studied theoretically. Conditions for time focusing are analyzed both analytically and numerically for double-acceleration-region TOF spectrometers. Expressions for the spectrometer mass resolution and for the critical delay time are deduced. Effects due to a leakage field in the first acceleration region are shown to be relevant under certain conditions. TOF peak shape simulations for the delayed extraction method are performed for emitted ions presenting a Maxwellian initial energy distribution. Calculations are compared to experimental results of Cs+ emission due to CsI laser ablation.

  7. A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

    CERN Document Server

    Ito, Y; Wada, M; Naimi, S; Smorra, C; Sonoda, T; Mita, H; Takamine, A; Okada, K; Ozawa, A; Wollnik, H

    2013-01-01

    A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ~27% for 23Na+ and ~5.1% for 7Li+ has been achieved.

  8. Start Detector for Time-of-Flight Spectrometers of Heavy Charged Particles

    CERN Document Server

    Aleksandrov, A A; Kamanin, D V; Kondratiev, B A; Penionzhkevich, Yu E

    2004-01-01

    Design description of a low gas pressure avalanche counter which is used as a start detector in time-of-flight spectrometers of heavy charged particles is presented. The detector has three-electrode construction with two wire anodes and a metallized cathode between the anodes. Pentane at a pressure of about 4 torr is used as a working gas. The results of the investigations obtained with the help of the sources of $\\alpha$-particles and spontaneous fission fragments of $^{252}{\\rm Cf}$ source are also presented.

  9. A radial collimator for a time-of-flight neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M. B.; Abernathy, D. L. [Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Niedziela, J. L.; Loguillo, M. J.; Overbay, M. A. [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-08-15

    We have engineered and installed a radial collimator for use in the scattered beam of a neutron time-of-flight spectrometer at a spallation neutron source. The radial collimator may be used with both thermal and epithermal neutrons, reducing the detected scattering intensity due to material outside of the sample region substantially. The collimator is located inside of the sample chamber of the instrument, which routinely cycles between atmospheric conditions and cryogenic vacuum. The oscillation and support mechanism of the collimator allow it to be removed from use without breaking vacuum. We describe here the design and characterization of this radial collimator.

  10. A radial collimator for a time-of-flight neutron spectrometer

    Science.gov (United States)

    Stone, M. B.; Niedziela, J. L.; Loguillo, M. J.; Overbay, M. A.; Abernathy, D. L.

    2014-08-01

    We have engineered and installed a radial collimator for use in the scattered beam of a neutron time-of-flight spectrometer at a spallation neutron source. The radial collimator may be used with both thermal and epithermal neutrons, reducing the detected scattering intensity due to material outside of the sample region substantially. The collimator is located inside of the sample chamber of the instrument, which routinely cycles between atmospheric conditions and cryogenic vacuum. The oscillation and support mechanism of the collimator allow it to be removed from use without breaking vacuum. We describe here the design and characterization of this radial collimator.

  11. Calibration of time of flight detectors using laser-driven neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Mirfayzi, S. R.; Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.; Green, A.; Alejo, A.; Jung, D. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Krygier, A. G.; Freeman, R. R. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Clarke, R. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Fuchs, J.; Vassura, L. [LULI, Ecole Polytechnique, CNRS, Route de Saclay, 91128 Palaiseau Cedex (France); Kleinschmidt, A.; Roth, M. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstrasse 9, D-64289 Darmstadt,Germany (Germany); Morrison, J. T. [Propulsion Systems Directorate, Air Force Research Lab, Wright Patterson Air Force Base, Ohio 45433 (United States); Najmudin, Z.; Nakamura, H. [Blackett Laboratory, Department of Physics, Imperial College, London SW7 2AZ (United Kingdom); Norreys, P. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Oliver, M. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Zepf, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Helmholtz Institut Jena, D-07743 Jena (Germany); Borghesi, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Institute of Physics of the ASCR, ELI-Beamlines Project, Na Slovance 2, 18221 Prague (Czech Republic)

    2015-07-15

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

  12. Resolving multipath interference in time-of-flight imaging via modulation frequency diversity and sparse regularization.

    Science.gov (United States)

    Bhandari, Ayush; Kadambi, Achuta; Whyte, Refael; Barsi, Christopher; Feigin, Micha; Dorrington, Adrian; Raskar, Ramesh

    2014-03-15

    Time-of-flight (ToF) cameras calculate depth maps by reconstructing phase shifts of amplitude-modulated signals. For broad illumination of transparent objects, reflections from multiple scene points can illuminate a given pixel, giving rise to an erroneous depth map. We report here a sparsity-regularized solution that separates K interfering components using multiple modulation frequency measurements. The method maps ToF imaging to the general framework of spectral estimation theory and has applications in improving depth profiles and exploiting multiple scattering.

  13. Time-of-Flight Mass Measurements and Their Importance for Nuclear Astrophysics

    Science.gov (United States)

    Matoš, M.; Estrade, A.; Amthor, A. M.; Bazin, D.; Becerril, A.; Elliot, T.; Famiano, M.; Gade, A.; Galaviz, D.; Lorusso, G.; Pereira, J.; Portillo, M.; Rogers, A.; Schatz, H.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.

    2009-03-01

    Atomic masses play an important role in nuclear astrophysics. The lack of experimental values for nuclides of interest has triggered a rapid development of new mass measurement devices around the world, including Time-of-Flight (TOF) mass measurements offering an access to the most exotic nuclides. Recently, the TOF-Brho technique that includes a position measurement for magnetic rigidity correction has been implemented at the NSCL. An experiment with a similar TOF-Brho technique is approved and planned at the next generation radioactive beam facility (RIBF) at RIKEN.

  14. A 3D scanning device for architectural survey based on time-of-flight technology

    Science.gov (United States)

    Fontana, Raffaella; Gambino, Maria Chiara; Gianfrate, Gabriella; Greco, Marinella; Pampaloni, Enrico; Pezzati, Luca

    2004-09-01

    This work is intended to show the results of a few architectural and archaeological surveys realized by means of a 3D scanning device, based on TOF (Time-Of-Flight) technology. The instrument was set up by the Art Diagnostic Group of the National Institute for Applied Optics (INOA) and it is composed by a high precision scanning system equipped with a commercial low-cost distance-meter. This device was projected in order to provide the following characteristics: reliability, good accuracy and compatibility with other systems and it is devoted to applications in Cultural Heritage field.

  15. Stopping power measurements with the Time-of-Flight (ToF) technique

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, Cristiano L., E-mail: fontana@pd.infn.it [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chen, Chien-Hung; Crespillo, Miguel L.; Graham, Joseph T.; Xue, Haizhou [Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Zhang, Yanwen; Weber, William J. [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

    2016-01-01

    A review of measurements of the stopping power of ions in matter is presented along with new measurements of the stopping powers of O, Si, Ti, and Au ions in self-supporting thin foils of SiO{sub 2}, Nb{sub 2}O{sub 5}, and Ta{sub 2}O{sub 5}. A Time-of-Flight system at the Ion Beam Materials Laboratory at the University of Tennessee, Knoxville, was used in transmission geometry in order to reduce experimental uncertainties. The resulting stopping powers show good precision and accuracy and corroborate previously quoted values in the literature. New stopping data are determined.

  16. Solid Phase Microextraction and Miniature Time-of-Flight Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Hiller, j.m.

    1999-01-26

    A miniature mass spectrometer, based on the time-of-flight principle, has been developed for the detection of chemical warfare agent precursor molecules. The instrument, with minor modifications, could fulfill many of the needs for sensing organic molecules in various Defense Programs, including Enhanced Surveillance. The basic footprint of the instrument is about that of a lunch box. The instrument has a mass range to about 300, has parts-per-trillion detection limits, and can return spectra in less than a second. The instrument can also detect permanent gases and is especially sensitive to hydrogen. In volume, the device could be manufactured for under $5000.

  17. High sensitivity probe absorption technique for time-of-flight measurements on cold atoms

    Indian Academy of Sciences (India)

    A K Mohapatra; C S Unnikrishnan

    2006-06-01

    We report on a phase-sensitive probe absorption technique with high sensitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms. We demonstrate the high sensitivity and figure of merit of the simple method by measuring the time-of-flight of atoms moving upwards from a magneto-optical trap released in the gravitational field.

  18. Performance Characteristics of a New Hybrid Triple Quadrupole Time-of-Flight Tandem Mass Spectrometer

    Science.gov (United States)

    Andrews, Genna L.; Simons, Brigitte L.; Young, J. Bryce; Hawkridge, Adam M.; Muddiman, David C.

    2011-01-01

    The TripleTOF 5600 System, a hybrid triple quadrupole time-of-flight mass spectrometer, was evaluated to explore the key figures of merit in generating peptide and protein identifications which included spectral acquisition rates, data quality, proteome coverage, and biological depth. Employing a Saccharomyces cerevisiae tryptic digest, careful consideration of several performance features demonstrated that the speed of the TripleTOF contributed most to the resultant data. The TripleTOF system was operated with 8, 20, and 50 MS/MS events in an effort to compare to other MS technologies and to demonstrate the abilities of the instrument platform. PMID:21619048

  19. Testing a new NIF neutron time-of-flight detector with a bibenzyl scintillator on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Glebov, V. Yu.; Forrest, C.; Knauer, J. P.; Pruyne, A.; Romanofsky, M.; Sangster, T. C.; Shoup, M. J. III; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States); Caggiano, J. A.; Carman, M. L.; Clancy, T. J.; Hatarik, R.; McNaney, J.; Zaitseva, N. P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2012-10-15

    A new neutron time-of-flight (nTOF) detector with a bibenzyl crystal as a scintillator has been designed and manufactured for the National Ignition Facility (NIF). This detector will replace a nTOF20-Spec detector with an oxygenated xylene scintillator currently operational on the NIF to improve the areal-density measurements. In addition to areal density, the bibenzyl detector will measure the D-D and D-T neutron yield and the ion temperature of indirect- and direct-drive-implosion experiments. The design of the bibenzyl detector and results of tests on the OMEGA Laser System are presented.

  20. TORCH - Cherenkov and Time-of-Flight PID Detector for the LHCb Upgrade at CERN

    Science.gov (United States)

    Föhl, K.; Brook, N.; Castillo García, L.; Conneely, T.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Milnes, J.; Piedigrossi, D.; Rademacker, J.; Ros Garcì a, A.; van Dijk, M.

    2016-05-01

    TORCH is a large-area precision time-of-flight detector, based on Cherenkov light production and propagation in a quartz radiator plate, which is read out at its edges. TORCH is proposed for the LHCb experiment at CERN to provide positive particle identification for kaons, and is currently in the Research-and-Development phase. A brief overview of the micro-channel plate photon sensor development, the custom-made electronics, and an introduction to the current test beam activities is given. Optical readout solutions are presented for the potential use of BaBar DIRC bar boxes as part of the TORCH configuration in LHCb.

  1. Tomography of correlation functions for ultracold atoms via time-of-flight images

    OpenAIRE

    ZHANG, WEI; Duan, L.-M.

    2009-01-01

    We propose to utilize density distributions from a series of time-of-flight images of an expanding cloud to reconstruct single-particle correlation functions of trapped ultra-cold atoms. In particular, we show how this technique can be used to detect off-diagonal correlations of atoms in a quasi-one-dimensional trap, where both real- and momentum- space correlations are extracted at a quantitative level. The feasibility of this method is analyzed with specific examples, taking into account fi...

  2. Time-of-flight detection of ultra-cold atoms using resonant frequency modulation imaging.

    Science.gov (United States)

    Hardman, K S; Wigley, P B; Everitt, P J; Manju, P; Kuhn, C C N; Robins, N P

    2016-06-01

    Resonant frequency modulation imaging is used to detect free falling ultra-cold atoms. A theoretical comparison of fluorescence imaging (FI) and frequency modulation imaging (FMI) is made, indicating that for low optical depth clouds, FMI accomplished a higher signal-to-noise ratio under conditions necessary for a 200 μm spatially resolved atom interferometer. A 750 ms time-of-flight measurement reveals near atom shot-noise limited number measurements of 2×106 Bose-condensed Rb87 atoms. The detection system is applied to high precision spinor BEC based atom interferometer.

  3. A 3D profile function suitable for integration of neutron time-of-flight single crystal diffraction peaks

    Science.gov (United States)

    Gutmann, Matthias J.

    2017-03-01

    A 3D profile function is presented suitable to integrate reflections arising in time-of-flight (TOF) single crystal neutron diffraction experiments. In order to account for the large asymmetry of the peak shape in the TOF direction, a 3D Gaussian ellipsoid in the pixel (x, z) and time-of-flight coordinates is convoluted with a rising and falling exponential along the time-of-flight direction. An analytic expression is derived, making it suitable for least-squares fitting. The application of this function in detector space or reciprocal space is straightforward.

  4. Novel time-of-flight fiber dispersion measurement technique using supercontinuum light sources and acousto-optical tunable filters.

    Science.gov (United States)

    Blume, Niels Göran; Wagner, Steven

    2015-07-20

    Long-distance fiber links require precise knowledge of fiber dispersion characteristics. Similar dispersion characteristics are necessary for supercontinuum broadband laser absorption spectroscopy (SCLAS) to allow proper data evaluation and species concentration determination, as well as numerous other applications. In this work, a time-of-flight approach to measuring the dispersion characteristic of fibers with supercontinuum laser light sources (SCLs) and acousto-optical tunable filters (AOTFs) is presented. Broadband emission of the SCL is filtered with a narrowband AOTF and dispersed in time by the fiber under test. By using the wavelength-specific delay, the dispersion characteristic can be calculated. The technique is especially suited for longer fibers and was verified against a state-of-the-art phase-shift-based dispersion measurement system. Advantages of the new approach include solely utilizing SCLAS system components, as well as a high level of automation and wide spectral coverage, ranging from 1100 to 1700 nm in a single measurement setup.

  5. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Directory of Open Access Journals (Sweden)

    T. Dickel

    2015-05-01

    Full Text Available 211Po ions in the ground and isomeric states were produced via 238U projectile fragmentation at 1000 MeV/u. The 211Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC. They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS. The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  6. Microextraction by packed sorbent liquid chromatography with time-of-flight mass spectrometry of triazines employing a molecularly imprinted polymer.

    Science.gov (United States)

    Andrade, Felipe Nascimento; Santos-Neto, Álvaro José; Lanças, Fernando Mauro

    2014-11-01

    Molecularly imprinted polymers for the determination of triazines were synthesized by precipitation using atrazine as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, and 2,2'-azobisisobutrynitrile as initiator. The polymers were characterized by infrared spectroscopy and scanning electron microscopy and packed in a device for microextraction by packed sorbent aiming for the preconcentration/cleanup of herbicides, such as atrazine, simazine, simetryn, ametryn, and terbutryn in corn samples. Liquid chromatography coupled with time-of-flight mass spectrometry was used for the separation and determination of the herbicides. The selectivity coefficient of molecularly imprinted polymers was compared with that of nonimprinted polymer for the binary mixtures of atrazine/propanil and atrazine/picloram, and the values obtained were 15.6 and 2.96, respectively. The analytical curve ranged from 10 to 80 μg/kg (r = 0.989) and the limits of detection and quantification in the corn matrices were 3.3 and 10 μg/kg, respectively. Intra- and interday precisions were Polymer synthesis was successfully applied to the cleanup and preconcentration of triazines from fortified corn samples with 91.1-109.1% of recovery.

  7. Characterizing and classifying water-based lubricants using direct analysis in real time(®)-time of flight mass spectrometry.

    Science.gov (United States)

    Maric, Mark; Bridge, Candice

    2016-09-01

    Lubricant analysis is a relatively recent addition to the examination protocol in sexual assault cases by the forensic science community. Currently, lubricants cannot be unequivocally identified, although their presence can be determined based on the detection of a few chemical components, i.e. polydimethylsiloxane, polyethylene glycol, glycerol or nonoxynol-9. Confirmation of their presence typically requires that an authentic reference sample be submitted and compared to the unknown sample to determine if they potentially came from the same source. In this study, 33 individual personal water-based lubricants were characterized by direct analysis in real time-time of flight mass spectroscopy (DART-TOFMS). The resultant mass spectral data were evaluated using well-established multivariate statistical techniques, such as principal component and linear discriminant analysis. Statistical analysis revealed six different groupings within the data that could be correlated to sub-categories of water-based lubricants that contain additives in the form of anesthetics, sensation enhancers and flavorings. This variability in the personal lubricant sources can be utilized to aid in identifying the specific type of lubricant when only a questioned sample is available.

  8. Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption

    Energy Technology Data Exchange (ETDEWEB)

    Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai, E-mail: ajai@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2014-06-15

    The early stage of formation of lithium plasma in a collinear—double pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8 nm and 610.3 nm), and ionic (548.4 nm and 478.8 nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

  9. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Dickel, T. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Plaß, W.R., E-mail: Wolfgang.R.Plass@exp2.physik.uni-giessen.de [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Ayet San Andres, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Ebert, J. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Geissel, H.; Haettner, E. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Hornung, C. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Miskun, I. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Pietri, S.; Purushothaman, S. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); and others

    2015-05-11

    {sup 211}Po ions in the ground and isomeric states were produced via {sup 238}U projectile fragmentation at 1000 MeV/u. The {sup 211}Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC). They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  10. Residue Determination of cis-Epoxiconazole Enantiomers in Fruit and Tea by Ultra Performance Convergence Chromatography Combined with Quadrupole Time-of-Flight Mass Spectrometry%超高效合相色谱-四极杆飞行时间质谱法测定水果和茶叶中手性农药顺式-氟环唑对映体残留

    Institute of Scientific and Technical Information of China (English)

    赵悦臣; 张新忠; 罗逢健; 周利; 陈宗懋; 崔新仪

    2016-01-01

    Abstract A chiral separation and residue determination method for cis-epoxiconazole enantiomers in apple, grape and tea samples was developed and validated by ultra performance convergence chromatography combined with quadrupole time-of-flight mass spectrometry ( UPC2-QTOF/MS) . The Chrial CCA column was used to separate cis-epoxiconazole enantiomers and the chromatography conditions ( mobile phase modifier and proportion, column temperature, automated backpressure regulator, and auxiliary solvent ) were optimized. Samples were extracted by acetonitrile, and respectively purified by Cleanert TPT or Pesti-Carb solid phase extraction ( SPE ) columns, then analyzed by UPC2-QTOF/MS. The optimum conditions were as follows:mobile phase was CO2/isopropanol (95: 5, V/V), flow-rate was 2. 0 mL/min, automated backpressure regulator (ABPR) was 13. 79 MPa, column temperature was 30℃, with a post-column mauxiliary solvent of methanol/water (1:1, V/V) containing 2 mmol/L ammonium formate. The analyte was quantified by matrix external standard method. The results showed that linear range of this method was 0. 01-1. 00 mg/L, and the correlation coefficients were above 0 . 99 . The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 005, 0. 025 and 0. 25 mg/kg) in fruit matrix were 67. 9%-92. 8% with relative standard deviations (RSDs, n=6) less than 10%, and the limit of quantification (LOQ) of enantiomers was 0. 005 mg/kg. The recoveries of cis-epoxiconazole enantiomers at three spiked levels (0. 01, 0. 05 and 0. 5 mg/kg) in black tea were 74 . 1% -84 . 0% with RSDs ( n=6 ) less than 8%, and the LOQ for these two enantiomers was 0. 01 mg/kg. This method is rapid, convenient and reliable, and could meet the requirement of residue analysis.%利用超高效合相色谱-四极杆飞行时间质谱( UPC2-QTOF/MS),建立了顺式-氟环唑在苹果、葡萄和茶叶中的手性对映体拆分与残留分析方法。对合相色谱条件(流动相改性剂及比

  11. An accurate air temperature measurement system based on an envelope pulsed ultrasonic time-of-flight technique.

    Science.gov (United States)

    Huang, Y S; Huang, Y P; Huang, K N; Young, M S

    2007-11-01

    A new microcomputer based air temperature measurement system is presented. An accurate temperature measurement is derived from the measurement of sound velocity by using an ultrasonic time-of-flight (TOF) technique. The study proposes a novel algorithm that combines both amplitude modulation (AM) and phase modulation (PM) to get the TOF measurement. The proposed system uses the AM and PM envelope square waveform (APESW) to reduce the error caused by inertia delay. The APESW ultrasonic driving waveform causes an envelope zero and phase inversion phenomenon in the relative waveform of the receiver. To accurately achieve a TOF measurement, the phase inversion phenomenon was used to sufficiently identify the measurement pulse in the received waveform. Additionally, a counter clock technique was combined to compute the phase shifts of the last incomplete cycle for TOF. The presented system can obtain 0.1% TOF resolution for the period corresponding to the 40 kHz frequency ultrasonic wave. Consequently, with the integration of a humidity compensation algorithm, a highly accurate and high resolution temperature measurement can be achieved using the accurate TOF measurement. Experimental results indicate that the combined standard uncertainty of the temperature measurement is approximately 0.39 degrees C. The main advantages of this system are high resolution measurements, narrow bandwidth requirements, and ease of implementation.

  12. TOFPET 2: A high-performance circuit for PET time-of-flight

    Energy Technology Data Exchange (ETDEWEB)

    Di Francesco, Agostino, E-mail: agodifra@lip.pt [LIP, Lisbon (Portugal); Bugalho, Ricardo [LIP, Lisbon (Portugal); PETsys Electronics, Oeiras (Portugal); Oliveira, Luis [CTS-UNINOVA, DEE FCT-UNL, Caparica (Portugal); Rivetti, Angelo [INFN - sez. Torino (Italy); Rolo, Manuel [LIP, Lisbon (Portugal); INFN - sez. Torino (Italy); Silva, Jose C.; Varela, Joao [LIP, Lisbon (Portugal); PETsys Electronics, Oeiras (Portugal)

    2016-07-11

    We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with (320 pF) capacitance the circuit has 24 (30) dB SNR, 75 (39) ps r.m.s. resolution, and 4 (8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.

  13. A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives

    Science.gov (United States)

    Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

    2011-12-01

    AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at ˜10-50 Hz and emits ˜106n/pulse at a peak current of 100 kA. Both sources emit 2.45±0.1 MeV (DD) neutron pulses of ˜25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm3 in volume.

  14. TOFPET 2: A high-performance circuit for PET time-of-flight

    Science.gov (United States)

    Di Francesco, Agostino; Bugalho, Ricardo; Oliveira, Luis; Rivetti, Angelo; Rolo, Manuel; Silva, Jose C.; Varela, Joao

    2016-07-01

    We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with (320 pF) capacitance the circuit has 24 (30) dB SNR, 75 (39) ps r.m.s. resolution, and 4 (8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.

  15. Times of Flight between a Source and a Detector observed from a GPS satelite

    CERN Document Server

    van Elburg, Ronald A J

    2011-01-01

    The Michelson-Morley experiment shows that the experimental outcome of an interference experiment does not depend on the constant velocity of the setup with respect to an inertial frame of reference. From this one can conclude the existence of an invariant velocity of light. However it does not follow from their experiment that a time-of-flight is reference frame independent. In fact the theory of special relativity predicts that the distance between the production location of a particle and the detection location will be changed in all reference frames which have a velocity component parallel to the baseline separating source and detector in a foton time-of-flight experiment. For the OPERA experiment we find that the associated correction is in the order of 32 ns. Because, judging from the information provided, the correction needs to be applied twice in the OPERA experiment the total correction to the final results is in the order of 64 ns. Thus bringing the apparent velocities of neutrino's back to a value...

  16. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures.

    Science.gov (United States)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A; Steuwer, Axel; Kiyanagi, Ryoji; Tremsin, Anton S; Knudsen, Erik B; Shinohara, Takenao; Willendrup, Peter K; da Silva Fanta, Alice Bastos; Iyengar, Srinivasan; Larsen, Peter M; Hanashima, Takayasu; Moyoshi, Taketo; Kadletz, Peter M; Krooß, Philipp; Niendorf, Thomas; Sales, Morten; Schmahl, Wolfgang W; Schmidt, Søren

    2017-08-25

    The physical properties of polycrystalline materials depend on their microstructure, which is the nano- to centimeter scale arrangement of phases and defects in their interior. Such microstructure depends on the shape, crystallographic phase and orientation, and interfacing of the grains constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure. The reconstruction algorithms have been validated by reconstructing two stacked Co-Ni-Ga single crystals, and by comparison with a grain map obtained by post-mortem electron backscatter diffraction (EBSD).

  17. Fast neutron measurements at the nELBE time-of-flight facility

    Directory of Open Access Journals (Sweden)

    Junghansa A. R.

    2015-01-01

    Full Text Available The compact neutron-time-of-flight facility nELBE at the superconducting electron accelerator ELBE of Helmholtz-Zentrum Dresden-Rossendorf has been rebuilt. A new enlarged experimental hall with a flight path of up to 10 m is available for neutron time-of-flight experiments in the fast energy range from about 50 keV to 10 MeV. nELBE is intended to deliver nuclear data of fast neutron nuclear interactions e.g. for the transmutation of nuclear waste and improvement of neutron physical simulations of innovative nuclear systems. The experimental programme consists of transmission measurements of neutron total cross sections, elastic and inelastic scattering cross section measurements, and neutron induced fission cross sections. The inelastic scattering to the first few excited states in 56Fe was investigated by measuring the gamma production cross section with an HPGe detector. The neutron induced fission of 242Pu was studied using fast ionisation chambers with large homogeneous actinide deposits.

  18. A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert [Alameda Applied Sciences Corporation, 3077 Teagarden Street, San Leandro, CA 94577 (United States); Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin [XIA LLC, 31057 Genstar Road, Hayward, CA 94544 (United States); Lane, Stephen [NSF Center for Biophotonics and School of Medicine, University of California Davis, Sacramento CA, 95817 (United States)

    2011-12-13

    AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at {approx}10-50 Hz and emits {approx}10{sup 6}n/pulse at a peak current of 100 kA. Both sources emit 2.45{+-}0.1 MeV(DD) neutron pulses of {approx}25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm{sup 3} in volume.

  19. Barrel time-of-flight detector for the PANDA experiment at FAIR

    CERN Document Server

    Gruber, L; Marton, J; Orth, H; Suzuki, K

    2015-01-01

    The barrel time-of-flight detector for the PANDA experiment at FAIR is foreseen as a Scintillator Tile (SciTil) Hodoscope based on several thousand small plastic scintillator tiles read-out with directly attached Silicon Photomultipliers (SiPMs). The main tasks of the system are an accurate determination of the time origin of particle tracks to avoid event mixing at high collission rates, relative time-of-flight measurements as well as particle identification in the low momentum regime. The main requirements are the use of a minimum material amount and a time resolution of $\\sigma < 100\\,\\mathrm{ps}$. We have performed extensive optimization studies and prototype tests to prove the feasibility of the SciTil design and finalize the R&D phase. In a 2.7 GeV/c proton beam at Forschungszentrum J\\"ulich a time resolution of about 80 ps has been achieved using SiPMs from KETEK and Hamamatsu with an active area of $3\\times3\\,\\mathrm{mm^2}$. Employing the Digital Photon Counter from Philips a time resolution of...

  20. TORCH: A Large-Area Detector for Precision Time-of-Flight Measurements at LHCb

    CERN Document Server

    Harnew, N

    2012-01-01

    The TORCH (Time Of internally Reflected CHerenkov light) is an innovative high-precision time-of-flight detector which is suitable for large areas, up to tens of square metres, and is being developed for the upgraded LHCb experiment. The TORCH provides a time-of-flight measurement from the imaging of photons emitted in a 1 cm thick quartz radiator, based on the Cherenkov principle. The photons propagate by total internal reflection to the edge of the quartz plane and are then focused onto an array of Micro-Channel Plate (MCP) photon detectors at the periphery of the detector. The goal is to achieve a timing resolution of 15 ps per particle over a flight distance of 10 m. This will allow particle identification in the challenging momentum region up to 20 GeV/c. Commercial MCPs have been tested in the laboratory and demonstrate the required timing precision. An electronics readout system based on the NINO and HPTDC chipset is being developed to evaluate an 8×8 channel TORCH prototype. The simulated performance...

  1. Barrel time-of-flight detector for the PANDA experiment at FAIR

    Science.gov (United States)

    Gruber, L.; Brunner, S. E.; Marton, J.; Orth, H.; Suzuki, K.

    2016-07-01

    The barrel time-of-flight detector for the PANDA experiment at FAIR is foreseen as a Scintillator Tile (SciTil) Hodoscope based on several thousand small plastic scintillator tiles read-out with directly attached Silicon Photomultipliers (SiPMs). The main tasks of the system are an accurate determination of the time origin of particle tracks to avoid event mixing at high collision rates, relative time-of-flight measurements as well as particle identification in the low momentum regime. The main requirements are the use of a minimum material amount and a time resolution of σ < 100 ps. We have performed extensive optimization studies and prototype tests to prove the feasibility of the SciTil design and finalize the R&D phase. In a 2.7 GeV/c proton beam at Forschungszentrum Jülich a time resolution of about 80 ps has been achieved using SiPMs from KETEK and Hamamatsu with an active area of 3 × 3mm2. Employing the Digital Photon Counter from Philips a time resolution of about 30 ps has been reached.

  2. Simulation of a new endcap time of flight system for the BESIII experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ullrich, Matthias; Jifeng, Hu; Kuehn, Wolfgang; Lange, Soeren; Liang, Yutie; Spruck, Bjoern; Werner, Marcel [2. Physikalisches Institut, Universitaet Giessen (Germany); Collaboration: BES III-Collaboration

    2012-07-01

    The BESIII experiment is located at the BEPC II collider in Beijing, China at the Institute for High Energy Physics, commonly known as IHEP. The symmetric e{sup +}e{sup -} experiment optimized for the investigation of {tau} and charm physics has already collected over 220M J/{Psi}, 106M {Psi}(2S), about 1fb{sup -1}{Psi}(3770) and 0.5 fb{sup -1}{Psi}(4040) events. Finishing the next run period in June 2012 the total amount of J/{Psi}/{Psi}(2S) events is expected to be 1 billion/0.7 billion, respectively. The actual endcap time of flight detector has a total time resolution of about 138 ps and is discussed to be replaced by a multigap resistive plate chamber (MRPC) providing a total time resolution of less than 80 ps. We report about the implementation of such type of detector into the BESIII offline software system (BOSS) as replacement of the actual endcap time of flight detector. A detailed simulation code based on Geant4 as well as a full reconstruction code has been implemented and can easily be utilized for event simulation and reconstruction.

  3. Pharmaceutical metabolite profiling using quadrupole/ion mobility spectrometry/time-of-flight mass spectrometry.

    Science.gov (United States)

    Chan, Eric C Y; New, Lee Sun; Yap, Chun Wei; Goh, Lin Tang

    2009-02-01

    The use of hybrid quadrupole ion mobility spectrometry time-of-flight mass spectrometry (Q/IMS/TOFMS) in the metabolite profiling of leflunomide (LEF) and acetaminophen (APAP) is presented. The IMS drift times (T(d)) of the drugs and their metabolites were determined in the IMS/TOFMS experiments and correlated with their exact monoisotopic masses and other in silico generated structural properties, such as connolly molecular area (CMA), connolly solvent-excluded volume (CSEV), principal moments of inertia along the X, Y and Z Cartesian coordinates (MI-X, MI-Y and MI-Z), inverse mobility and collision cross-section (CCS). The correlation of T(d) with these parameters is presented and discussed. IMS/TOF tandem mass spectrometry experiments (MS(2) and MS(3)) were successfully performed on the N-acetyl-p-benzoquinoneimine glutathione (NAPQI-GSH) adduct derived from the in vitro microsomal metabolism of APAP. As comparison, similar experiments were also performed using hybrid triple quadrupole linear ion trap mass spectrometry (QTRAPMS) and quadrupole time-of-flight mass spectrometry (QTOFMS). The abilities to resolve the product ions of the metabolite within the drift tube and fragment the ion mobility resolved product ions in the transfer travelling wave-enabled stacked ring ion guide (TWIG) demonstrated the potential applicability of the Q/IMS/TOFMS technique in pharmaceutical metabolite profiling.

  4. Structural measurements on several alamethicin peptides by the time-of-flight correlation technique

    Science.gov (United States)

    Poppe-Schriemer, N.; Ens, W.; O'Neil, J. D.; Spicer, V.; Standing, K. G.; Westmore, J. B.; Yee, A. A.

    1995-05-01

    Time-of-flight correlation methods have been used to determine the primary structure of the major component in a nonstandard preparation of alamethicins, and to give some sequence information about minor components. The peptide (MW [approximate] 2000 u) is blocked at the N terminus with an acetyl group and has a primary alcohol rather than a carboxyl group at the C terminus, so the usual wet chemical sequencing methods cannot be applied. Upon bombardment with 25 keVI- ions, the peptide, deposited on the surface of a solid target, produces both molecular ions and prompt fragment ions (i.e. ions formed at or very near the surface of the target). After acceleration, these ions may undergo metastable decay as they pass along the flight tube of a reflecting time-of-flight mass spectrometer. Measurement of the correlations between the neutral and charged daughters from these decompositions determines the decay pattern of each ion, which in turn yields definitive information about the sequence of the original peptide. All events are recorded on magnetic tape and analyzed off-line, so a single run on the spectrometer provides information on the decay of every ion produced at the target, i.e. information similar to that obtainable from a complete set of daughter ion scans on a multiple sector or triple quadrupole instrument.

  5. Lanthanum halide scintillators for time-of-flight 3-D pet

    Science.gov (United States)

    Karp, Joel S.; Surti, Suleman

    2008-06-03

    A Lanthanum Halide scintillator (for example LaCl.sub.3 and LaBr.sub.3) with fast decay time and good timing resolution, as well as high light output and good energy resolution, is used in the design of a PET scanner. The PET scanner includes a cavity for accepting a patient and a plurality of PET detector modules arranged in an approximately cylindrical configuration about the cavity. Each PET detector includes a Lanthanum Halide scintillator having a plurality of Lanthanum Halide crystals, a light guide, and a plurality of photomultiplier tubes arranged respectively peripherally around the cavity. The good timing resolution enables a time-of-flight (TOF) PET scanner to be developed that exhibits a reduction in noise propagation during image reconstruction and a gain in the signal-to-noise ratio. Such a PET scanner includes a time stamp circuit that records the time of receipt of gamma rays by respective PET detectors and provides timing data outputs that are provided to a processor that, in turn, calculates time-of-flight (TOF) of gamma rays through a patient in the cavity and uses the TOF of gamma rays in the reconstruction of images of the patient.

  6. Time-of-flight detector applied to mass measurements in Rare-RI Ring

    Energy Technology Data Exchange (ETDEWEB)

    Nagae, D., E-mail: nagae@tac.tsukuba.ac.jp [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Abe, Y. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Okada, S.; Ozawa, A. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Yamaguchi, T. [Department of Physics, Saitama University, Shimo-Okubo 255, Sakura-ku Saitama-shi, 338-8570 (Japan); Suzuki, H.; Moriguchi, T. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Ishibashi, Y. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Fukuoka, S.; Nishikiori, R.; Niwa, T. [Institute of Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Suzuki, T.; Suzaki, F.; Sato, K.; Furuki, H.; Ichihashi, N.; Miyazawa, S. [Department of Physics, Saitama University, Shimo-Okubo 255, Sakura-ku Saitama-shi, 338-8570 (Japan); Yamaguchi, Y.; Uesaka, T.; Wakasugi, M. [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2013-12-15

    Highlights: • We have developed Time-of-flight detectors for the Rare-RI Ring. • Measurements to evaluate a time resolution and a detection efficiency have been performed using alpha particle and heavy ion beams. • Preliminary time resolution is about 130 ps and detection efficiency is about 56% for the heavy ion beams. -- Abstract: A large time-of-flight (TOF) detector has been developed for the Rare-RI Ring. This detector consists of a Multi Channel Plate (MCP) and a carbon foil. Secondary electrons from the carbon foil are transported to the MCP by crossed electric and magnetic fields. In order to cover the beam size of the ring, a large and thin carbon foil (100 mm × 50 mm{sup 2} and 60 μg/cm{sup 2}) is used as a sensitive material. The time resolution of σ≈130 ps, the detection efficiency about 56% and a position dependence of the TOF about 1 ns are obtained. A calculated position dependence of TOF adopting experimental (inhomogeneous) electric field and a homogeneous magnetic field is in agreement with the experimental one. These results suggest that the homogeneity of electric field is important to improve the time resolution in the large size detector.

  7. Constant-momentum acceleration time-of-flight mass spectrometry with energy focusing.

    Science.gov (United States)

    Dennis, Elise A; Ray, Steven J; Gundlach-Graham, Alexander W; Enke, Christie G; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

    2013-12-01

    Fundamental aspects of constant-momentum acceleration time-of-flight mass spectrometry (CMA-TOFMS) are explored as a means to improve mass resolution. By accelerating all ions to the same momentum rather than to the same energy, the effects of the initial ion spatial and energy distributions upon the total ion flight time are decoupled. This decoupling permits the initial spatial distribution of ions in the acceleration region to be optimized independently, and energy focus, including ion turn-around-time error, to be accomplished with a linear-field reflectron. Constant-momentum acceleration also linearly disperses ions across time according to mass-to-charge (m/z) ratio, instead of the quadratic relationship between flight time and m/z found in conventional TOFMS. Here, CMA-TOFMS is shown to achieve simultaneous spatial and energy focusing over a selected portion of the mass spectrum. An orthogonal-acceleration time-of-flight system outfitted with a reduced-pressure DC glow discharge (GD) ionization source is used to demonstrate CMA-TOFMS with atomic ions. The influence of experimental parameters such as the amplitude and width of the time-dependent CMA pulse on mass resolution is investigated, and a useful CMA-TOFMS focusing window of 2 to 18 Da is found for GD-CMA-TOFMS.

  8. TOF plotter—a program to perform routine analysis time-of-flight mass spectral data

    Science.gov (United States)

    Knippel, Brad C.; Padgett, Clifford W.; Marcus, R. Kenneth

    2004-03-01

    The main article discusses the operation and application of the program to mass spectral data files. This laboratory has recently reported the construction and characterization of a linear time-of-flight mass spectrometer (ToF-MS) utilizing a radio frequency glow discharge ionization source. Data acquisition and analysis was performed using a digital oscilloscope and Microsoft Excel, respectively. Presently, no software package is available that is specifically designed for time-of-flight mass spectral analysis that is not instrument dependent. While spreadsheet applications such as Excel offer tremendous utility, they can be cumbersome when repeatedly performing tasks which are too complex or too user intensive for macros to be viable. To address this situation and make data analysis a faster, simpler task, our laboratory has developed a Microsoft Windows-based software program coded in Microsoft Visual Basic. This program enables the user to rapidly perform routine data analysis tasks such as mass calibration, plotting and smoothing on x- y data sets. In addition to a suite of tools for data analysis, a number of calculators are built into the software to simplify routine calculations pertaining to linear ToF-MS. These include mass resolution, ion kinetic energy and single peak identification calculators. A detailed description of the software and its associated functions is presented followed by a characterization of its performance in the analysis of several representative ToF-MS spectra obtained from different GD-ToF-MS systems.

  9. Studying time of flight imaging through scattering media across multiple size scales (Conference Presentation)

    Science.gov (United States)

    Velten, Andreas

    2017-05-01

    Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.

  10. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification of mycobacteria in routine clinical practice

    National Research Council Canada - National Science Library

    El Khéchine, Amel; Couderc, Carine; Flaudrops, Christophe; Raoult, Didier; Drancourt, Michel

    2011-01-01

    .... Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) has previously been proven to effectively identify mycobacteria grown in high-concentration inocula from collections...

  11. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals

    Science.gov (United States)

    Zhang, Y.; Huang, S. L.; Wang, S.; Zhao, W.

    2016-05-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert-Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of <1% and thus can act as a universal time-of-flight extraction method for narrowband Lamb wave detection signals.

  12. Development and fundamental investigation of Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS)

    Energy Technology Data Exchange (ETDEWEB)

    Tarik, Mohamed [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Lotito, Giovanni [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Whitby, James A. [TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Mechanics of Materials and Nanostructures Laboratory, Empa - Materials Science and Technology, Feuerwerkerstr. 39, 3602 Thun (Switzerland); Koch, Joachim [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland); Fuhrer, Katrin; Gonin, Marc [TOFWERK AG, Uttigenstr. 22, 3600 Thun (Switzerland); Michler, Johann [Mechanics of Materials and Nanostructures Laboratory, Empa - Materials Science and Technology, Feuerwerkerstr. 39, 3602 Thun (Switzerland); Bolli, Jean-Luc [Ecole d' ingenieurs de Geneve, 4 Prairie, 1202 Geneva (Switzerland); Guenther, Detlef [ETH Zurich, D-CHAB, Laboratory of inorganic chemistry, Wolfgang-Pauli-Str. 10, 8093 Zurich (Switzerland)], E-mail: guenther@inorg.chem.ethz.ch

    2009-03-15

    Glow Discharge (GD) spectroscopy is a well known and accepted technique for the bulk and surface composition analysis, while laser ablation (LA) provides analysis with high spatial-resolution analysis in LIBS (laser-induced breakdown spectroscopy) or when coupled to inductively coupled plasma spectrometry (ICP-OES or ICP-MS). This work concerns the construction of a Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS) instrument to study the analytical capabilities resulting from the interaction of a laser-generated sample plume with a pulsed glow discharge. Two ablation configurations were studied in detail. In a first approach, the laser-generated plume was introduced directly into the GD, while the second approach generated the plume inside the GD. The ablated material was introduced at different times with respect to the discharge pulse in order to exploit the efficient ionization in the GD plasma. For both LA-GD configurations, direct ablation into the afterglow of the pulsed glow discharge leads to an ion signal enhancement of up to a factor of 7, as compared to the ablation process alone under the same experimental conditions. The LA-GD enhancement was found to occur exclusively in the GD afterglow, with a maximum ablation S/N occurring in a few hundred microseconds after the termination of the glow discharge. The duration of the enhanced signal is about two milliseconds. Both the laser pulse energy and the position of the ablation plume (with respect to the sampling orifice) were found to affect the amount of mass entering the afterglow region and consequently, the enhancement factor of ionization.

  13. Development and fundamental investigation of Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS)

    Science.gov (United States)

    Tarik, Mohamed; Lotito, Giovanni; Whitby, James A.; Koch, Joachim; Fuhrer, Katrin; Gonin, Marc; Michler, Johann; Bolli, Jean-Luc; Günther, Detlef

    2009-03-01

    Glow Discharge (GD) spectroscopy is a well known and accepted technique for the bulk and surface composition analysis, while laser ablation (LA) provides analysis with high spatial-resolution analysis in LIBS (laser-induced breakdown spectroscopy) or when coupled to inductively coupled plasma spectrometry (ICP-OES or ICP-MS). This work concerns the construction of a Laser Ablation Glow Discharge Time-Of-Flight Mass Spectrometry (LA-GD-TOFMS) instrument to study the analytical capabilities resulting from the interaction of a laser-generated sample plume with a pulsed glow discharge. Two ablation configurations were studied in detail. In a first approach, the laser-generated plume was introduced directly into the GD, while the second approach generated the plume inside the GD. The ablated material was introduced at different times with respect to the discharge pulse in order to exploit the efficient ionization in the GD plasma. For both LA-GD configurations, direct ablation into the afterglow of the pulsed glow discharge leads to an ion signal enhancement of up to a factor of 7, as compared to the ablation process alone under the same experimental conditions. The LA-GD enhancement was found to occur exclusively in the GD afterglow, with a maximum ablation S/N occurring in a few hundred microseconds after the termination of the glow discharge. The duration of the enhanced signal is about two milliseconds. Both the laser pulse energy and the position of the ablation plume (with respect to the sampling orifice) were found to affect the amount of mass entering the afterglow region and consequently, the enhancement factor of ionization.

  14. Classification of wheat varieties: Use of two-dimensional gel electrophoresis for varieties that can not be classified by matrix assisted laser desorption/ionization-time of flight-mass spectrometry and an artificial neural network

    DEFF Research Database (Denmark)

    Jacobsen, Susanne; Nesic, Ljiljana; Petersen, Marianne Kjerstine;

    2001-01-01

    Analyzing a gliadin extract by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI- TOF-MS) combined with an artificial neural network (ANN) is a suitable method for identification of wheat varieties. However, the ANN can not distinguish between all different wheat...

  15. Development of grazing incidence devices for space-borne time of flight mass spectrometry

    Science.gov (United States)

    Cadu, A.; Devoto, P.; Louarn, P.; Sauvaud, J.-A.

    2012-04-01

    Time of flight mass spectrometer is widely used to study space plasmas in planetary and solar missions. This space-borne instrument selects ions in function of their energy through an electrostatic analyzer. Particles are then post-accelerated to energies in the range of 20 keV to cross a carbon foil. At the foil exit, electrons are emitted and separated from ion beam in the time of flight section. A first detector (a Micro-Channel Plate or MCP) emits a start signal at electron arrival and a second one emits a stop signal at incident ion end of path. The time difference gives the speed of the particle and its mass can be calculated, knowing its initial energy. However, current instruments suffer from strong limitations. The post acceleration needs very high voltage power supplies which are heavy, have a high power consumption and imply technical constraints for the development. A typical instrument weighs from 5 to 6 kg, includes a 20 kV power supply, consumes a least 5 W and encounters corona effect and electrical breakdown problems. Moreover, despite the particle high energy range, scattering and straggling phenomena in the carbon foil significantly reduce the instrument overall resolution. Some methods, such as electrostatic focus lenses or reflectrons, really improve mass separation but global system efficiency remains very low because of the charge state dependence of such devices. The main purpose of our work is to replace carbon foil by grazing incidence MCP's - also known as MPO's, for Micro Pore Optics - for electron emission. Thus, incident particles would back-scatter onto the channel inner surface with an angle of a few degrees. With this solution, we can decrease dispersion sources and lower the power supplies to post accelerate ions. The result would be a lighter and simpler instrument with a substantial resolution improvement. We have first simulated MPO's behavior with TRIM and MARLOWE Monte-Carlo codes. Energy scattering and output angle computed

  16. Toward Respiratory Assessment Using Depth Measurements from a Time-of-Flight Sensor

    Science.gov (United States)

    Sharp, Charles; Soleimani, Vahid; Hannuna, Sion; Camplani, Massimo; Damen, Dima; Viner, Jason; Mirmehdi, Majid; Dodd, James W.

    2017-01-01

    Introduction: There is increasing interest in technologies that may enable remote monitoring of respiratory disease. Traditional methods for assessing respiratory function such as spirometry can be expensive and require specialist training to perform and interpret. Remote, non-contact tracking of chest wall movement has been explored in the past using structured light, accelerometers and impedance pneumography, but these have often been costly and clinical utility remains to be defined. We present data from a 3-Dimensional time-of-flight camera (found in gaming consoles) used to estimate chest volume during routine spirometry maneuvres. Methods: Patients were recruited from a general respiratory physiology laboratory. Spirometry was performed according to international standards using an unmodified spirometer. A Microsoft Kinect V2 time-of-flight depth sensor was used to reconstruct 3-dimensional models of the subject's thorax to estimate volume-time and flow-time curves following the introduction of a scaling factor to transform measurements to volume estimates. The Bland-Altman method was used to assess agreement of model estimation with simultaneous recordings from the spirometer. Patient characteristics were used to assess predictors of error using regression analysis and to further explore the scaling factors. Results: The chest volume change estimated by the Kinect camera during spirometry tracked respiratory rate accurately and estimated forced vital capacity (FVC) and vital capacity to within ± 150 ml difference. Linear regression including age, gender, height, weight, and pack years of smoking explained 37.0% of the variance in the scaling factor for volume estimation. This technique had a positive predictive value of 0.833 to detect obstructive spirometry. Conclusion: These data illustrate the potential of 3D time-of-flight cameras to remotely monitor respiratory rate. This is not a replacement for conventional spirometry and needs further refinement

  17. Toward Respiratory Assessment Using Depth Measurements from a Time-of-Flight Sensor.

    Science.gov (United States)

    Sharp, Charles; Soleimani, Vahid; Hannuna, Sion; Camplani, Massimo; Damen, Dima; Viner, Jason; Mirmehdi, Majid; Dodd, James W

    2017-01-01

    Introduction: There is increasing interest in technologies that may enable remote monitoring of respiratory disease. Traditional methods for assessing respiratory function such as spirometry can be expensive and require specialist training to perform and interpret. Remote, non-contact tracking of chest wall movement has been explored in the past using structured light, accelerometers and impedance pneumography, but these have often been costly and clinical utility remains to be defined. We present data from a 3-Dimensional time-of-flight camera (found in gaming consoles) used to estimate chest volume during routine spirometry maneuvres. Methods: Patients were recruited from a general respiratory physiology laboratory. Spirometry was performed according to international standards using an unmodified spirometer. A Microsoft Kinect V2 time-of-flight depth sensor was used to reconstruct 3-dimensional models of the subject's thorax to estimate volume-time and flow-time curves following the introduction of a scaling factor to transform measurements to volume estimates. The Bland-Altman method was used to assess agreement of model estimation with simultaneous recordings from the spirometer. Patient characteristics were used to assess predictors of error using regression analysis and to further explore the scaling factors. Results: The chest volume change estimated by the Kinect camera during spirometry tracked respiratory rate accurately and estimated forced vital capacity (FVC) and vital capacity to within ± 150 ml difference. Linear regression including age, gender, height, weight, and pack years of smoking explained 37.0% of the variance in the scaling factor for volume estimation. This technique had a positive predictive value of 0.833 to detect obstructive spirometry. Conclusion: These data illustrate the potential of 3D time-of-flight cameras to remotely monitor respiratory rate. This is not a replacement for conventional spirometry and needs further refinement

  18. Quantitative myocardial blood flow imaging with integrated time-of-flight PET-MR.

    Science.gov (United States)

    Kero, Tanja; Nordström, Jonny; Harms, Hendrik J; Sörensen, Jens; Ahlström, Håkan; Lubberink, Mark

    2017-12-01

    The use of integrated PET-MR offers new opportunities for comprehensive assessment of cardiac morphology and function. However, little is known on the quantitative accuracy of cardiac PET imaging with integrated time-of-flight PET-MR. The aim of the present work was to validate the GE Signa PET-MR scanner for quantitative cardiac PET perfusion imaging. Eleven patients (nine male; mean age 59 years; range 46-74 years) with known or suspected coronary artery disease underwent (15)O-water PET scans at rest and during adenosine-induced hyperaemia on a GE Discovery ST PET-CT and a GE Signa PET-MR scanner. PET-MR images were reconstructed using settings recommended by the manufacturer, including time-of-flight (TOF). Data were analysed semi-automatically using Cardiac VUer software, resulting in both parametric myocardial blood flow (MBF) images and segment-based MBF values. Correlation and agreement between PET-CT-based and PET-MR-based MBF values for all three coronary artery territories were assessed using regression analysis and intra-class correlation coefficients (ICC). In addition to the cardiac PET-MR reconstruction protocol as recommended by the manufacturer, comparisons were made using a PET-CT resolution-matched reconstruction protocol both without and with TOF to assess the effect of time-of-flight and reconstruction parameters on quantitative MBF values. Stress MBF data from one patient was excluded due to movement during the PET-CT scanning. Mean MBF values at rest and stress were (0.92 ± 0.12) and (2.74 ± 1.37) mL/g/min for PET-CT and (0.90 ± 0.23) and (2.65 ± 1.15) mL/g/min for PET-MR (p = 0.33 and p = 0.74). ICC between PET-CT-based and PET-MR-based regional MBF was 0.98. Image quality was improved with PET-MR as compared to PET-CT. ICC between PET-MR-based regional MBF with and without TOF and using different filter and reconstruction settings was 1.00. PET-MR-based MBF values correlated well with PET-CT-based MBF values

  19. Advanced 360o FOV, wide energy range, non-HV, gated time of flight mass spectrometers for Small Satellites and Cubesats

    Science.gov (United States)

    Paschalidis, N.; Jones, S.; Rodriguez, M.; Sittler, E. C., Jr.; Chornay, D. J.; Uribe, P.; Cameron, T.; Nanan, G.

    2015-12-01

    The time of flight technique is widely used for composition analysis of space plasma instruments. The foil - MCP/CEM combination is commonly used for E x TOF mass analysis at the cost of energy threshold, scattering, and direct particle interaction which ultimately affect performance. An alternative method especially effective at low energies is gated time of flight where the start foil is replaced with electric gating. There are several advantages of electric gating, including elimination of heavy HVPS required for pre-reacceleration to overcome foil thresholds, non- destructive interaction with atomic and molecular ions before analysis, and electronic controllability including geometric factor adjustment for flux dynamic range, FOV optimization, electronic filtering of most abundant elements in favor of minor species, and other properties affecting directly the scientific and engineering performance of the instruments. In addition special secondary emission surfaces can be used for triple coincidence when needed. The combination of electric gating and special surfaces works in an extensive energy range from 0 to tens of KeV without the need of start foil/HVPS making thus the use attractive to small satellites and cubesats. Those characteristics will be elaborated in the context of a gated time of flight wide field of view and energy range ion spectrometer combined with a neutral mass spectrometer (WINMS) developed at GSFC. The instrument prototypes have mass resolution adequate to separate N, O, OH, OH2; also static from ram moving H allowing thus separation of outgassing from ambient gases. A first implementation INMS with a mass <600 grams and size <1.5U is the main payload of the EXOCUBE Cubesat mission launched in January 2015 and already produced flight data; a second upgraded implementation is on onboard the GSFC Dellingr 6U CubeSat scheduled for launch in late 2015; and ongoing developments are baselined for other satellite missions.

  20. Fluence measurement at the neutron time of flight experiment at CERN

    CERN Document Server

    Weiss, Christina; Jericha, Erwin

    At the neutron time of flight facility n_TOF at CERN a new spallation target was installed in 2008. In 2008 and 2009 the commissioning of the new target took place. During the summer 2009 a fission chamber of the Physikalisch Technische Bundesanstalt (PTB) Braunschweig was used for the neutron fluence measurement. The evaluation of the data recorded with this detector is the primary topic of this thesis. Additionally a neutron transmission experiment with air has been performed at the TRIGA Mark II reactor of the Atomic Institute of the Austrian Universities (ATI). The experiment was implemented to clarify a question about the scattering cross section of molecular gas which could not be answered clearly via the literature. This problem came up during the evaluations for n_TOF.

  1. Calibration of a neutron time-of-flight multidetector system for an intensity interferometry experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ghetti, R. E-mail: roberta.ghetti@nuclear.lu.se; Colonna, N.; Helgesson, J.; Avdeichikov, V.; Golubev, P.; Jakobsson, B.; Tagliente, G.; Brandenburg, S.; Kravchuk, V.L.; Wilschut, H.W.; Kopecky, S.; Anderson, E.W.; Nadel-Turonski, P.; Westerberg, L.; Bellini, V.; Sperduto, M.L.; Sutera, C

    2004-01-11

    We present the details of an experiment on light particle interferometry. In particular, we focus on a time-of-flight technique which uses a cyclotron RF signal as a start and a liquid scintillator time signal as a stop, to measure neutron energy in the range of E{sub n}{approx}1.8-150 MeV. This dynamic range (up to 300 ns) is much larger than the beam bunch separation (54 ns) of the AGOR cyclotron (KVI). However, the problem of a short burst period is overcome by using the time information obtained from a fast projectile fragment phoswich detector. The complete analysis procedure to extract the final neutron kinetic energy spectra, is discussed.

  2. New high-resolution electrostatic ion mass analyzer using time of flight

    Science.gov (United States)

    Hamilton, D. C.; Gloeckler, G.; Ipavich, F. M.; Lundgren, R. A.; Sheldon, R. B.

    1990-01-01

    The design of a high-resolution ion-mass analyzer is described, which is based on an accurate measurement of the time of flight (TOF) of ions within a region configured to produce a harmonic potential. In this device, the TOF, which is independent of ion energy, is determined from a start pulse from secondary electrons produced when the ion passes through a thin carbon foil at the entrance of the TOF region and at a stop pulse from the ion striking a microchannel plate upon exciting the region. A laboratory prototype instrument called 'VMASS' was built and was tested at the Goddard Space Flight Center electrostatic accelerator, showing a good mass resolution of the instrument. Sensors of the VMASS type will form part of the WIND Solar Wind and Suprathermal Ion experiment, the Soho mission, and the Advanced Composition Explorer.

  3. An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors

    Energy Technology Data Exchange (ETDEWEB)

    Shuai, P. [Research Center for Hadron Physics, National Laboratory of Heavy Ion Accelerator Facility in Lanzhou and University of Science and Technology of China, Hefei 230026 (China); Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Xu, X., E-mail: xuxing@impcas.ac.cn [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhang, Y.H., E-mail: yhzhang@impcas.ac.cn [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Xu, H.S. [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Litvinov, Yu. A. [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt (Germany); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Wang, M. [Key Laboratory of High Precision Nuclear Spectroscopy, Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); and others

    2016-06-01

    Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nuclei with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam separated in-flight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS. Therefore, the momentum measurement in addition to the revolution period of stored ions is crucial to reduce the influence of the momentum spread on the standard deviation of the revolution period, which would lead to a much improved mass resolving power of IMS. One of the proposals to upgrade IMS is that the velocity of secondary ions could be directly measured by using two time-of-flight (double TOF) detectors installed in a straight section of a storage ring. In this paper, we outline the principle of IMS with double TOF detectors and the method to correct the momentum spread of stored ions.

  4. Encrypted Three-dimensional Dynamic Imaging using Snapshot Time-of-flight Compressed Ultrafast Photography.

    Science.gov (United States)

    Liang, Jinyang; Gao, Liang; Hai, Pengfei; Li, Chiye; Wang, Lihong V

    2015-10-27

    Compressed ultrafast photography (CUP), a computational imaging technique, is synchronized with short-pulsed laser illumination to enable dynamic three-dimensional (3D) imaging. By leveraging the time-of-flight (ToF) information of pulsed light backscattered by the object, ToF-CUP can reconstruct a volumetric image from a single camera snapshot. In addition, the approach unites the encryption of depth data with the compressed acquisition of 3D data in a single snapshot measurement, thereby allowing efficient and secure data storage and transmission. We demonstrated high-speed 3D videography of moving objects at up to 75 volumes per second. The ToF-CUP camera was applied to track the 3D position of a live comet goldfish. We have also imaged a moving object obscured by a scattering medium.

  5. ISAC time-of-flight system with laser-based calibration

    Energy Technology Data Exchange (ETDEWEB)

    Verzilov, V.A., E-mail: verzilov@triumf.ca

    2015-06-11

    The time-of-flight (TOF) system is available at the ISAC rare isotope facility to measure the energy of stable and radioactive ion beams in the range of 0.5–22 Mev/u. The system, comprised of three secondary electron emission based monitors, is operated with practically all available beam intensities starting from as low as 10{sup 3} ions per second. Recently the system was equipped with the calibration setup based on a 266 nm ultraviolet laser. Laser light interacting with the TOF monitors generates secondary electrons due to the photoelectric effect and acts as a reference beam traveling at a well- known velocity. After calibration, accuracy of energy measurements improved to be better than 0.1%.

  6. MONSTER: a time of flight spectrometer for β-delayed neutron emission measurements

    Science.gov (United States)

    Garcia, A. R.; Martínez, T.; Cano-Ott, D.; Castilla, J.; Guerrero, C.; Marín, J.; Martínez, G.; Mendoza, E.; Ovejero, M. C.; Reillo, E. M.; Santos, C.; Tera, F. J.; Villamarín, D.; Nolte, R.; Agramunt, J.; Algora, A.; Tain, J. L.; Banerjee, K.; Bhattacharya, C.; Pentillä, H.; Rinta-Antila, S.; Gorelov, D.

    2012-05-01

    The knowledge of the β-decay properties of nuclei contributes decisively to our understanding of nuclear phenomena: the β-delayed neutron emission of neutron rich nuclei plays an important role in the nucleosynthesis r-process and constitutes a probe for nuclear structure of very neutron rich nuclei providing information about the high energy part of the full beta strength (Sβ) function. In addition, β-delayed neutrons are essential for the control and safety of nuclear reactors. In order to determine the neutron energy spectra and emission probabilities from neutron precursors a MOdular Neutron time-of-flight SpectromeTER (MONSTER) has been proposed for the DESPEC experiment at the future FAIR facility. The design of MONSTER and status of its construction are reported in this work.

  7. The MRPC-based ALICE Time-Of-Flight detector: Commissioning and first performance

    Energy Technology Data Exchange (ETDEWEB)

    Akindinov, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Alici, A., E-mail: Andrea.Alici@cern.ch [Sezione INFN, Bologna (Italy); Museo Storico della Fisica e Centro Studi e Ricerche & #x27; Enrico Fermi& #x27; , Roma (Italy); CERN, Geneva (Switzerland); Antonioli, P. [Sezione INFN, Bologna (Italy); Arcelli, S.; Basile, M. [Sezione INFN, Bologna (Italy); Dipartimento di Fisica dell& #x27; Universita, Bologna (Italy); Bellini, F. [Sezione INFN, Bologna (Italy); Caffarri, D. [Sezione INFN, Bologna (Italy); Dipartimento di Fisica dell& #x27; Universita, Bologna (Italy); INFN and University of Padova (Italy); Cara Romeo, G. [Sezione INFN, Bologna (Italy); Cifarelli, L. [Sezione INFN, Bologna (Italy); Dipartimento di Fisica dell& #x27; Universita, Bologna (Italy); Cindolo, F. [Sezione INFN, Bologna (Italy); De Caro, A.; De Gruttola, D.; De Pasquale, S. [Dipartimento di Fisica dell& #x27; Universita and INFN, Salerno (Italy); Doroud, K. [World Laboratory, Geneva (Switzerland); Fusco Girard, M. [Dipartimento di Fisica dell& #x27; Universita and INFN, Salerno (Italy); Guerzoni, B. [Sezione INFN, Bologna (Italy); Dipartimento di Fisica dell& #x27; Universita, Bologna (Italy); Hatzifotiadou, D. [Sezione INFN, Bologna (Italy); Jung, W.W.; Kim, D.W.; Kim, J.S. [Department of Physics, Gangneung-Wonju National University, Gangneung (Korea, Republic of); and others

    2012-01-01

    The ALICE Time-Of-Flight (TOF) detector is a cylindrical array with a total area of about 150 m{sup 2} and more than 153,000 readout channels; it will allow charged hadron separation for momentum up to a few GeV/c. The very good performance required for such a system has been achieved by means of the Multigap Resistive Plate Chamber (MRPC) whose time resolution is better than 50 ps with an overall efficiency close to 100%. The TOF detector is fully installed since April 2008; it has successfully been operated during cosmic ray data taking. The very good stability, noise level and time performance are reported here. The status of the calibration and the first physics results with the TOF detector are given.

  8. High precision electric gate for time-of-flight ion mass spectrometers

    Science.gov (United States)

    Sittler, Edward C. (Inventor)

    2011-01-01

    A time-of-flight mass spectrometer having a chamber with electrodes to generate an electric field in the chamber and electric gating for allowing ions with a predetermined mass and velocity into the electric field. The design uses a row of very thin parallel aligned wires that are pulsed in sequence so the ion can pass through the gap of two parallel plates, which are biased to prevent passage of the ion. This design by itself can provide a high mass resolution capability and a very precise start pulse for an ion mass spectrometer. Furthermore, the ion will only pass through the chamber if it is within a wire diameter of the first wire when it is pulsed and has the right speed so it is near all other wires when they are pulsed.

  9. Time-of-flight expansion of trapped dipolar Fermi gases: from collisionless to hydrodynamic regime

    CERN Document Server

    Veljic, Vladimir; Pelster, Axel

    2016-01-01

    A recent time-of-flight (TOF) expansion experiment with polarized fermionic erbium atoms measured a Fermi surface deformation from a sphere to an ellipsoid due to dipole-dipole interaction, thus confirming previous theoretical predictions. Here we perform a systematic study of the ground-state properties and TOF dynamics for trapped dipolar Fermi gases from the collisionless to the hydrodynamic regime at zero temperature. To this end we solve analytically the underlying Boltzmann-Vlasov equation within the relaxation-time approximation in the vicinity of equilibrium by using a suitable rescaling of the equilibrium distribution. The resulting ordinary differential equations for the respective scaling parameters are then solved numerically for experimentally realistic parameters and relaxation times that correspond to the collisionless, collisional, and hydrodynamic regime. The equations for the collisional regime are first solved in the approximation of a fixed relaxation time, and then this approach is extend...

  10. Figures of Merit for Indirect Time-of-Flight 3D Cameras: Definition and Experimental Evaluation

    Directory of Open Access Journals (Sweden)

    Matteo Perenzoni

    2011-11-01

    Full Text Available Indirect Time-of-Flight (I-TOF cameras can be implemented in a number of ways, each with specific characteristics and performances. In this paper a comprehensive analysis of the implementation possibilities is developed in order to model the main performances with a high level of abstraction. After the extraction of the main characteristics for the high-level model, several figures of merit (FoM are defined with the purpose of obtaining a common metric: noise equivalent distance, correlated and uncorrelated power responsivity, and background light rejection ratio. The obtained FoMs can be employed for the comparison of different implementations of range cameras based on the I-TOF method: specifically, they are applied for several different sensors developed by the authors in order to compare their performances.

  11. Star Time of Flight Readout Electronics, Daq, and Cosmic Ray Test Stand

    Science.gov (United States)

    Schambach, J.; Hoffmann, G.; Kajimoto, K.; Bridges, L.; Eppley, G.; Liu, J.; Llope, B.; Nussbaum, T.; Mesa, C.

    The new Time-of-Flight (TOF) subsystem for STAR at RHIC will have 3840 6-pad Multigap Resistive Plate Chambers (MRPC) distributed over 120 trays. Each tray contains 192 channels and three types of electronics cards: “TINO”, “TDIG” and “TCPU”. Every 30 trays send data to a “THUB” card that interfaces to STAR trigger and transmits data over fiber to a STAR DAQ fiber receiver. TINO contains analog front end electronics based on the CERN/LAA NINO custom IC. TDIG digitizes the data using the CERN HPTDC ASIC. TCPU formats and buffers the digital information. A cosmic ray test system comprised of three plastic scintillators, 4 MRPC modules, and TOF prototype electronics is used to determine the timing resolution to be achieved for the entire TOF system. Overall timing resolution of 80 - 110 ps has been achieved.

  12. Imaging a single atom in a time-of-flight experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrmanek, A; Tuchendler, C; Grangier, P; Sortais, Y R P; Browaeys, A [Laboratoire Charles Fabry, Institut d' Optique, CNRS, Universite de Paris-Sud, Campus Polytechnique, 2 avenue Augustin Fresnel, RD 128, 91127 Palaiseau Cedex (France); Lance, A M, E-mail: yvan.sortais@institutoptique.f [Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD 20899 (United States)

    2010-05-15

    We perform fluorescence imaging of a single {sup 87}Rb atom after its release from an optical dipole trap. The time-of-flight expansion of the atomic spatial density distribution is observed by accumulating many single atom images. The position of the atom is revealed with a spatial resolution close to 1 {mu}m by a single-photon event, induced by a short resonant probe. The expansion yields a measure of the temperature of a single atom, which is in very good agreement with the value obtained by an independent measurement based on a release-and-recapture method. The analysis presented in this paper provides a way of calibrating an imaging system useful for experimental studies involving a few atoms confined in a dipole trap.

  13. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures

    DEFF Research Database (Denmark)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A.

    2017-01-01

    constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND...... enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time....... The reconstruction algorithms have been validated by reconstructing two stacked Co-Ni-Ga single crystals, and by comparison with a grain map obtained by post-mortem electron backscatter diffraction (EBSD)....

  14. Application of time-of-flight secondary ion mass spectrometry to automobile paint analysis.

    Science.gov (United States)

    Lee, Y; Han, S; Yoon, J H; Kim, Y M; Shon, S K; Park, S W

    2001-06-01

    Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides a method of elemental analysis that can distinguish among automotive paint samples of the same or nearly the same color. TOF-SIMS survey spectra were employed to determine the relative abundances of elements in the surface layers of the paint chips. The depth profile of paint samples permitted the analysis of small paint chips, the reproducible results for specific elements, and the identification of each car paint. Seventy-three samples of blue, red, white, and silver automobile paints from the major manufacturers in Korea were investigated using high resolution TOF-SIMS technique. It was found that paints of the same color produced by different manufacturers could be distinguished by this technique. TOF-SIMS is a reliable, nondestructive, and small area analyzing method for characterization of the elemental composition of automotive paint chips.

  15. Real-Time Discrete SPAD Array Readout Architecture for Time of Flight PET

    CERN Document Server

    Tétrault, M -A; Boisvert, A; Thibaudeau, C; Dubois, F; Fontaine, R; Pratte, J -F

    2014-01-01

    Single photon avalanche diode (SPAD) arrays have proven themselves as serious candidates for time of flight positron emission tomography (PET). Discrete readout schemes mitigate the low-noise requirements of analog schemes and offer very fine control over threshold levels and timing pickup strategies. A high optical fill factor is paramount to timing performance in such detectors, and consequently space is limited for closely integrated electronics. Nonetheless, a production, daily used PET scanner must minimize bandwidth usage, data volume, data analysis time and power consumption and therefore requires a real-time readout and data processing architecture as close to the detector as possible. We propose a fully digital, embedded real-time readout architecture for SPAD-based detector. The readout circuit is located directly under the SPAD array instead of within or beside it to remove the fill factor versus circuit capabilities tradeoff. The overall real-time engine reduces transmitted data by a factor of 8 i...

  16. The Time of Flight electronics for the PAMELA experiment in space

    Science.gov (United States)

    Osteria, G.; Russo, S.

    2008-05-01

    PAMELA, a cosmic ray telescope, was launched into space on 15th June 2006 from the Baikonur cosmodrome aboard of a Soyuz-U and it is in continuous data tacking since 11 July 2006. The Time of Flight system of the PAMELA telescope allows both to distinguish electrons to antiprotons up to about 2 GeV and to measure the absolute charge of the particle. In order to perform these goals the requested time resolution for the whole ToF system is σt>200ps. To fulfill the detector requirements the read out electronics is been required to have a time resolution better than 60 ps with wide dynamic range for charge measurements. The peculiarity of the developed electronics arises from the need to obtain such a time resolution operating in a satellite environment, which implies low-power consumption, radiation hardness, redundancy and high reliability.

  17. The Time of Flight electronics for the PAMELA experiment in space

    Energy Technology Data Exchange (ETDEWEB)

    Osteria, G. [INFN sez.di Napoli, 80126 Napoli (Italy); Russo, S. [Dipartimento di Scienze Fisiche Universita' ' Federico II' , 80126 Napoli (Italy)], E-mail: srusso@na.infn.it

    2008-05-15

    PAMELA, a cosmic ray telescope, was launched into space on 15th June 2006 from the Baikonur cosmodrome aboard of a Soyuz-U and it is in continuous data tacking since 11 July 2006. The Time of Flight system of the PAMELA telescope allows both to distinguish electrons to antiprotons up to about 2 GeV and to measure the absolute charge of the particle. In order to perform these goals the requested time resolution for the whole ToF system is {sigma}{sub t}>200ps. To fulfill the detector requirements the read out electronics is been required to have a time resolution better than 60 ps with wide dynamic range for charge measurements. The peculiarity of the developed electronics arises from the need to obtain such a time resolution operating in a satellite environment, which implies low-power consumption, radiation hardness, redundancy and high reliability.

  18. A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Y., E-mail: yito@riken.jp [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Schury, P. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States); Wada, M.; Naimi, S. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Smorra, C. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Sonoda, T. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mita, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Takamine, A. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoyama Gakuin University, 4-4-25 Shibuya, Shibuya-ku, Tokyo 150-8366 (Japan); Okada, K. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan); Ozawa, A. [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Wollnik, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States)

    2013-12-15

    Highlights: • Fast cooling time: 2 ms. • High efficiency: ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +}. • 100% Duty cycle with double trap system. -- Abstract: A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +} has been achieved.

  19. A miniature laser ablation time-of-flight mass spectrometer for in situ planetary exploration

    Science.gov (United States)

    Rohner, Urs; Whitby, James A.; Wurz, Peter

    2003-12-01

    We report the development and testing of a miniature mass spectrometer and ion source intended to be deployed on an airless planetary surface to measure the elemental and isotopic composition of rocks and soils. Our design concentrates at this stage on the proposed BepiColombo mission to the planet Mercury. The mass analyser is an axially symmetric reflectron time-of-flight design. The ion source utilizes a laser induced plasma, which is directly coupled into the mass analyser. Laser ablation gives high spatial resolution, and avoids the need for sample preparation. Our prototype instrument has a demonstrated mass resolution m/Dgrm (FWHM) in excess of 600 and a predicted dynamic range of better than four orders of magnitude. Isotopic fractionation effects are found to be minor. We estimate that a flight instrument would have a mass of 500 g (including all electronics), a volume of 650 cm3 and could operate on 3 W power.

  20. Time-of-flight calibration of a 6Li glass epithermal neutron detector

    Science.gov (United States)

    Livingston; Saleh; Block; Brand

    2000-10-01

    The curing of Portland cement concrete involves the conversion of water from a free to a bound state. The process can be monitored nondestructively by measuring the shift in the neutron energy spectrum in the epithermal range (0.025-1 eV). A tuned array of 6Li glass detectors has been constructed with varying efficiencies over the epithermal energy range. To determine the efficiency of each detector as a function of neutron energy, it is necessary to calibrate it against a reference neutron spectrum. This was accomplished using a time-of-flight approach with a pulsed neutron beam produced at the Gaerttner LINAC Laboratory at Rensselaer Polytechnic Institute. With a neutron flight path of 25 m it was possible to determine the neutron detector efficiencies to an energy resolution of 11 microeV. The data showed good agreement with the detector design calculations.

  1. Digital signal processing for time of flight measurements of muons at sea level

    Energy Technology Data Exchange (ETDEWEB)

    Augusto, C.R.A. [Instituto de Fisica Universidade Federal Fluminense, 24210-130, Niteroi, RJ (Brazil); Navia, C.E., E-mail: navia@if.uff.b [Instituto de Fisica Universidade Federal Fluminense, 24210-130, Niteroi, RJ (Brazil); Lopes do Valle, R.; Silva, T.F. da [Instituto de Fisica Universidade Federal Fluminense, 24210-130, Niteroi, RJ (Brazil)

    2009-12-21

    This paper presents digital signal processing techniques for obtaining high accuracy in time of flight (TOF) measurements of muons at sea level. The Hilbert transformation of the original signal is employed as suitable time signal behavior for extracting the start time of the muon signal. Here we have used the Hilbert transformation incorporated into LabVIEW software and, as a data acquisition system, a two channel Tektronix oscilloscope running at a 2.0 GHz sample rate per channel. The muon TOF in the vertical Tupi telescope, made with two scintillator detectors separated by a distance of 3 m, is determined with an accuracy of some 1.5 ns. In this paper we report this TOF method that allows to obtain the speed, {beta}=v/c, and consequently the rigidity (energy) of an incident particle (muon).

  2. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures

    DEFF Research Database (Denmark)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A.

    2017-01-01

    constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND......-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure...... enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time...

  3. Beer fingerprinting by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight Mass Spectrometry.

    Science.gov (United States)

    Šedo, Ondrej; Márová, Ivana; Zdráhal, Zbyněk

    2012-11-15

    A method allowing parallel fingerprinting of proteins and maltooligosaccharides directly from untreated beer samples is presented. These two classes of compounds were detected by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight-Mass Spectrometry (MALDI-TOF-MS) analysis of beer mixed with 2,5-dihydroxybenzoic acid solution. The maltooligosaccharide profiles acquired from the MALDI sample spot center were not found characteristic for beers of different source and technology. On the other hand, according to profiles containing protein signals acquired from crystals formed on the border of the MALDI sample spot, we were able to distinguish beer samples of the same brand produced by different breweries. The discriminatory abilities of the method were further examined on a set of 17 lager beers, where the fingerprints containing protein signals enabled resolution of majority of examined brands. We propose MALDI-TOF-MS profiling as a rapid tool for beer brewing technology process monitoring, quality control, and determination of beer authenticity.

  4. Integrated multi-channel receiver for a pulsed time-of-flight laser radar

    Science.gov (United States)

    Jiang, Yan; Liu, Ruqing; Zhu, Jingguo

    2015-04-01

    An integrated multi-channel receiver for a pulsed time-of-flight (TOF) laser rangefinder has been designed in this paper. The receiver chip as an important component of the laser radar device has been implemented in a 0.18um CMOS process. It consists of sixteen channels and every channel includes preamplifier, amplifier stages, high-pass filter and a timing discriminator which contains a timing comparator and a noise comparator. Each signal paths is independent of other channels. Based on the simulations, the bandwidth and transimpedance of the amplifier channel are 652MHz, 99dBΩ. Under the simulation condition of TT corner and 27°C, the propagation delay of the discriminator is 2.15ns and the propagation delay dispersion is 223ps. The power consumption during continuous measurement is 810mW, and the operating temperature range of the device is -10~60°C.

  5. Invited article: polarization "down under": the polarized time-of-flight neutron reflectometer PLATYPUS.

    Science.gov (United States)

    Saerbeck, T; Klose, F; Le Brun, A P; Füzi, J; Brule, A; Nelson, A; Holt, S A; James, M

    2012-08-01

    This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

  6. Invited Article: Polarization ``Down Under'': The polarized time-of-flight neutron reflectometer PLATYPUS

    Science.gov (United States)

    Saerbeck, T.; Klose, F.; Le Brun, A. P.; Füzi, J.; Brule, A.; Nelson, A.; Holt, S. A.; James, M.

    2012-08-01

    This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

  7. Laser ranging by time-of-flight measurement of femtosecond light pulses

    Science.gov (United States)

    Kim, Young-Jin

    2014-04-01

    Time-of-flight (TOF) measurement of femtosecond light pulses was investigated for laser ranging of long distances with sub-micrometer precision in the air. The bandwidth limitation of the photo-detection electronics used in timing femtosecond pulses was overcome by adopting a type-II nonlinear second-harmonic crystal that permits producing the balanced optical cross-correlation signal between two overlapped light pulses. This method offered a sub-femtosecond timing resolution in determining the temporal offset between two pulses through lock-in control of the pulse repetition rate with reference to the atomic clock. The exceptional ranging capability was verified by measuring various distances from 1.5 m to 700 m. This method is found suited for terrestrial land surveying and space missions of formation-flying satellites.

  8. High precision laser ranging by time-of-flight measurement of femtosecond pulses

    Science.gov (United States)

    Lee, Joohyung; Lee, Keunwoo; Lee, Sanghyun; Kim, Seung-Woo; Kim, Young-Jin

    2012-06-01

    Time-of-flight (TOF) measurement of femtosecond light pulses was investigated for laser ranging of long distances with sub-micrometer precision in the air. The bandwidth limitation of the photo-detection electronics used in timing femtosecond pulses was overcome by adopting a type-II nonlinear second-harmonic crystal that permits the production of a balanced optical cross-correlation signal between two overlapping light pulses. This method offered a sub-femtosecond timing resolution in determining the temporal offset between two pulses through lock-in control of the pulse repetition rate with reference to the atomic clock. The exceptional ranging capability was verified by measuring various distances of 1.5, 60 and 700 m. This method is found well suited for future space missions based on formation-flying satellites as well as large-scale industrial applications for land surveying, aircraft manufacturing and shipbuilding.

  9. Background optimization for the neutron time-of-flight spectrometer NEAT

    Energy Technology Data Exchange (ETDEWEB)

    Günther, G., E-mail: gerrit.guenther@helmholtz-berlin.de; Russina, M., E-mail: margarita.russina@helmholtz-berlin.de

    2016-08-21

    The neutron time-of-flight spectrometer NEAT at BER II is currently undergoing a major upgrade where an important aspect is the prevention of parasitic scattering to enhance the signal-to-noise ratio. Here, we discuss the impact of shielding to suppress parasitic scattering from two identified sources of background: the sample environment and detector tubes. By means of Monte Carlo simulations and a modification of the analytical model of Copley et al. [Copley and Cook, 1994], the visibility functions of instrument parts are computed for different shielding configurations. According to three selection criteria, namely suppression of background, transmission and detection limit, the parameters of an oscillating radial collimator are optimized for NEAT's default setup. Moreover, different configurations of detector shielding are discussed to prevent cross-talk within the radial detector system.

  10. Time-of-flight PET data determine the attenuation sinogram up to a constant.

    Science.gov (United States)

    Defrise, Michel; Rezaei, Ahmadreza; Nuyts, Johan

    2012-02-21

    In positron emission tomography (PET), a quantitative reconstruction of the tracer distribution requires accurate attenuation correction. We consider situations where a direct measurement of the attenuation coefficient of the tissues is not available or is unreliable, and where one attempts to estimate the attenuation sinogram directly from the emission data by exploiting the consistency conditions that must be satisfied by the non-attenuated data. We show that in time-of-flight PET, the attenuation sinogram is determined by the emission data except for a constant and that its gradient can be estimated efficiently using a simple analytic algorithm. The stability of the method is illustrated numerically by means of a 2D simulation.

  11. Neutral particle energy analyser based on time of flight technique for EXTRAP-T2R

    Energy Technology Data Exchange (ETDEWEB)

    Cecconello, M. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Fusion Plasma Physics; Costa, S.; Murari, A.; Barzon, A. [Consorzio RFX, Padova (Italy)

    2001-07-01

    An important and not well-understood problem in the Reversed Field Pinch configuration is the anomalous ion heating. In all Ohmically heated RFPs, the ion temperature has been experimentally observed to be higher than can be accounted for by equilibration of energy from an Ohmically heated electron population. The mechanism driving the ions to such high energies is still debated. Different possible explanations have been investigated: kinetic Alfven waves turbulence, MHD relaxation processes and the excitation of an ion electrostatic wave by supra-thermal electrons. The measurement of the ion temperature is important in order to evaluate confinement. Furthermore, measurements can provide information on the mechanism behind the anomalous ion heating. The ion temperature is calculated from the neutral particles energy spectrum obtained by a neutral particles energy analyser based on the time of flight specifically developed for EXTRAP - T2R and here described in detail.

  12. Objective Error Criterion for Evaluation of Mapping Accuracy Based on Sensor Time-of-Flight Measurements

    Directory of Open Access Journals (Sweden)

    Billur Barshan

    2008-12-01

    Full Text Available An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well.

  13. The CDFII Time-Of-Flight Detector and Impact on Beauty Flavor Tagging

    CERN Document Server

    Grozis, C; Stanek, R; Kim, D H; Kim, M S; Kim, Y K; Vermendi, G; Anikeev, K; Bauer, G; Furic, I K; Korn, A J; Kravchenko, I V; Mulhearn, M; Paus, C; Pavlon, S; Sumorok, K; Chen, C; Jones, M; Kononenko, W; Kroll, J; Mayers, G M; Newcomer, M; Oldeman, R G C; Usynin, D; Berg, R V; Bellettini, Giorgio; Cerri, C; Menzione, A; De Cecco, S; Depedis, D; Dionisi, C; Giagu, S; Di Girolamo, A; Rescigno, M; Zanello, L; Cabrera, S; Fernández, J; Gómez, G; Piedra, J; Rodrigo, T; Ruiz, A; Vila, I; Vilar, R; Ahn, M; Kim, B J; Kim, S B; Cho, I; Lee, J; Kaneko, H; Kazama, A; Kim, S; Sato, K; Ukegawa, F; Paus, Ch.

    2002-01-01

    The new CDFII detector incorporates a Time-of-Flight detector (TOF), employing plastic scintillator bars and fine-mesh photomultipliers. Since August 2001 the TOF system has been fully instrumented and integrated into the CDFII data acquisition system. With a design goal of $100 ps$ resolution the TOF system will provide at least two standard deviations separation between $K^{\\pm}$ and $\\pi^{\\pm}$ for momenta $p<1.6 GeV/c$, complementing low momentum particle identification by means of the specific ionization energy loss measured in the drift chamber. We describe the design of the TOF detector and discuss the current status of its calibration and initial performances. Finally we review the expected impact of the TOF detector in the flavor tagging of neutral $B_S$ meson.

  14. Distance Measurement Error in Time-of-Flight Sensors Due to Shot Noise

    Science.gov (United States)

    Illade-Quinteiro, Julio; Brea, Víctor M.; López, Paula; Cabello, Diego; Doménech-Asensi, Gines

    2015-01-01

    Unlike other noise sources, which can be reduced or eliminated by different signal processing techniques, shot noise is an ever-present noise component in any imaging system. In this paper, we present an in-depth study of the impact of shot noise on time-of-flight sensors in terms of the error introduced in the distance estimation. The paper addresses the effect of parameters, such as the size of the photosensor, the background and signal power or the integration time, and the resulting design trade-offs. The study is demonstrated with different numerical examples, which show that, in general, the phase shift determination technique with two background measurements approach is the most suitable for pixel arrays of large resolution. PMID:25723141

  15. Distance Measurement Error in Time-of-Flight Sensors Due to Shot Noise

    Directory of Open Access Journals (Sweden)

    Julio Illade-Quinteiro

    2015-02-01

    Full Text Available Unlike other noise sources, which can be reduced or eliminated by different signal processing techniques, shot noise is an ever-present noise component in any imaging system. In this paper, we present an in-depth study of the impact of shot noise on time-of-flight sensors in terms of the error introduced in the distance estimation. The paper addresses the effect of parameters, such as the size of the photosensor, the background and signal power or the integration time, and the resulting design trade-offs. The study is demonstrated with different numerical examples, which show that, in general, the phase shift determination technique with two background measurements approach is the most suitable for pixel arrays of large resolution.

  16. Heavy ion time-of-flight ERDA of high dose metal implanted germanium

    Energy Technology Data Exchange (ETDEWEB)

    Dytlewski, N.; Evans, P.J.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Bunder, J. [New South Wales Univ., Wollongong, NSW (Australia). Wollongong Univ. Coll

    1996-12-31

    With the thick Ge substrates used in ion implantation, RBS can have difficulty in resolving the mass-depth ambiguities when analysing materials composed of mixtures of elements with nearly equal masses. Additional, and complimentary techniques are thus required. This paper reports the use of heavy ion time-of-flight elastic recoil detection analysis (ToF- ERDA), and conventional RBS in the analysis of Ge(100) implanted with high dose Ti and Cu ions from a MEWA ion source . Heavy ion ToF ERDA has been used to resolve, and profile the implanted transition metal species, and also to study any oxygen incorporation into the sample resulting from the implantation, or subsequential reactions with air or moisture. This work is part of a study on high dose metal ion implantation of medium atomic weight semiconductor materials. 13 refs., 6 figs.

  17. An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors

    CERN Document Server

    Shuai, P; Zhang, Y H; Xu, H S; Litvinov, Yu A; Wang, M; Tu, X L; Blaum, K; Zhou, X H; Yuan, Y J; Yan, X L; Chen, X C; Chen, R J; Fu, C Y; Ge, Z; Huang, W J; Xing, Y M; Zeng, Q

    2016-01-01

    Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nuclei with very short half-lives down to several tens of microseconds, using the cocktail beam separated in-flight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS. Therefore, the momentum measurement in addition to the revolution period of stored ions is crucial to reduce the influence of momentum spread on the standard deviation of the revolution period, which would lead to a much improved mass resolving power of IMS. One of the proposals to upgrade IMS is that the velocity of secondary ions could be directly measured by using two time-of-flight (double TOF) detectors installed in the straight section of storage ring. In this paper, we outline the principle of IMS with double TOF detectors and the method to correct the momentum spread of stored ions.

  18. Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions

    Science.gov (United States)

    Getty, S. A.; Brinckerhoff, W. B.; Cornish, T.; Ecelberger, S. A.; Li, X.; Floyd, M. A. Merrill; Chanover, N.; Uckert, K.; Voelz, D.; Xiao, X.; Tawalbeh, R.; Glenar, D.; Elsila, J. E.; Callahan, M.

    2012-01-01

    Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) is a versatile, low-complexity instrument class that holds significant promise for future landed in situ planetary missions that emphasize compositional analysis of surface materials. Here we describe a 5kg-class instrument that is capable of detecting and analyzing a variety of analytes directly from rock or ice samples. Through laboratory studies of a suite of representative samples, we show that detection and analysis of key mineral composition, small organics, and particularly, higher molecular weight organics are well suited to this instrument design. A mass range exceeding 100,000 Da has recently been demonstrated. We describe recent efforts in instrument prototype development and future directions that will enhance our analytical capabilities targeting organic mixtures on primitive and icy bodies. We present results on a series of standards, simulated mixtures, and meteoritic samples.

  19. TOFwave: reproducibility in biomarker discovery from time-of-flight mass spectrometry data.

    Science.gov (United States)

    Chierici, Marco; Albanese, Davide; Franceschi, Pietro; Furlanello, Cesare

    2012-11-01

    Many are the sources of variability that can affect reproducibility of disease biomarkers from time-of-flight (TOF) Mass Spectrometry (MS) data. Here we present TOFwave, a complete software pipeline for TOF-MS biomarker identification, that limits the impact of parameter tuning along the whole chain of preprocessing and model selection modules. Peak profiles are obtained by a preprocessing based on Continuous Wavelet Transform (CWT), coupled with a machine learning protocol aimed at avoiding selection bias effects. Only two parameters (minimum peak width and a signal to noise cutoff) have to be explicitly set. The TOFwave pipeline is built on top of the mlpy Python package. Examples on Matrix-Assisted Laser Desorption and Ionization (MALDI) TOF datasets are presented. Software prototype, datasets and details to replicate results in this paper can be found at http://mlpy.sf.net/tofwave/.

  20. Data reduction for time-of-flight small-angle neutron scattering with virtual neutrons

    Science.gov (United States)

    Du, Rong; Tian, Haolai; Zuo, Taisen; Tang, Ming; Yan, Lili; Zhang, Junrong

    2017-09-01

    Small-angle neutron scattering (SANS) is an experimental technique to detect material structures in the nanometer to micrometer range. The solution of the structural model constructed from SANS strongly depends on the accuracy of the reduced data. The time-of-flight (TOF) SANS data are dependent on the wavelength of the pulsed neutron source. Therefore, data reduction must be handled very carefully to transform measured neutron events into neutron scattering intensity. In this study, reduction algorithms for TOF SANS data are developed and optimized using simulated data from a virtual neutron experiment. Each possible effect on the measured data is studied systematically, and suitable corrections are performed to obtain high-quality data. This work will facilitate scientific research and the instrument design at China Spallation Neutron Source.

  1. Geometry Survey of the Time-of-Flight Neutron-Elastic Scattering (Antonella) Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Oshinowo, Babatunde O. [Fermilab; Izraelevitch, Federico [Buenos Aires U.

    2016-10-17

    The Antonella experiment is a measurement of the ionization efficiency of nuclear recoils in silicon at low energies [1]. It is a neutron elastic scattering experiment motivated by the search for dark matter particles. In this experiment, a proton beam hits a lithium target and neutrons are produced. The neutron shower passes through a collimator that produces a neutron beam. The beam illuminates a silicon detector. With a certain probability, a neutron interacts with a silicon nucleus of the detector producing elastic scattering. After the interaction, a fraction of the neutron energy is transferred to the silicon nucleus which acquires kinetic energy and recoils. This kinetic energy is then dissipated in the detector producing ionization and thermal energy. The ionization produced is measured with the silicon detector electronics. On the other hand, the neutron is scattered out of the beam. A neutron-detector array (made of scintillator bars) registers the neutron arrival time and the scattering angle to reconstruct the kinematics of the neutron-nucleus interaction with the time-of-flight technique [2]. In the reconstruction equations, the energy of the nuclear recoil is a function of the scattering angle with respect to the beam direction, the time-of-flight of the neutron and the geometric distances between components of the setup (neutron-production target, silicon detector, scintillator bars). This paper summarizes the survey of the different components of the experiment that made possible the off-line analysis of the collected data. Measurements were made with the API Radian Laser Tracker and I-360 Probe Wireless. The survey was completed at the University of Notre Dame, Indiana, USA in February 2015.

  2. Time-frequency energy density precipitation method for time-of-flight extraction of narrowband Lamb wave detection signals.

    Science.gov (United States)

    Zhang, Y; Huang, S L; Wang, S; Zhao, W

    2016-05-01

    The time-of-flight of the Lamb wave provides an important basis for defect evaluation in metal plates and is the input signal for Lamb wave tomographic imaging. However, the time-of-flight can be difficult to acquire because of the Lamb wave dispersion characteristics. This work proposes a time-frequency energy density precipitation method to accurately extract the time-of-flight of narrowband Lamb wave detection signals in metal plates. In the proposed method, a discrete short-time Fourier transform is performed on the narrowband Lamb wave detection signals to obtain the corresponding discrete time-frequency energy density distribution. The energy density values at the center frequency for all discrete time points are then calculated by linear interpolation. Next, the time-domain energy density curve focused on that center frequency is precipitated by least squares fitting of the calculated energy density values. Finally, the peak times of the energy density curve obtained relative to the initial pulse signal are extracted as the time-of-flight for the narrowband Lamb wave detection signals. An experimental platform is established for time-of-flight extraction of narrowband Lamb wave detection signals, and sensitivity analysis of the proposed time-frequency energy density precipitation method is performed in terms of propagation distance, dispersion characteristics, center frequency, and plate thickness. For comparison, the widely used Hilbert-Huang transform method is also implemented for time-of-flight extraction. The results show that the time-frequency energy density precipitation method can accurately extract the time-of-flight with relative error of wave detection signals.

  3. Liquid chromatography coupled with time-of-flight and ion trap mass spectrometry for qualitative analysis of herbal medicines

    Institute of Scientific and Technical Information of China (English)

    Xiao-Fei Chen; Hai-Tang Wu; Guang-Guo Tan; Zhen-Yu Zhu; Yi-Feng Chai

    2011-01-01

    With the expansion of herbal medicine (HM) market, the issue on how to apply up-to- date analytical tools on qualitative analysis of HMs to assure their quality, safety and efficacy has been arousing great attention. Due to its inherent characteristics of accurate mass measurements and multiple stages analysis, the integrated strategy of liquid chromatography (LC) coupled with time-of-flight mass spectrometry (TOF-MS) and ion trap mass spectrometry (IT-MS) is well-suited to be performed as qualitative analysis tool in this field. The purpose of this review is to provide an overview on the potential of this integrated strategy, including the review of general features of LC-IT-MS and LC-TOF-MS, the advantages of their combination, the common procedures for structure elucidation, the potential of LC-hybrid-IT-TOF/MS and also the summary and discussion of the applications of the integrated strategy for HM qualitative analysis (2006-2011). The advantages and future developments of LC coupled with IT and TOF-MS are highlighted.

  4. Ion spectrometer composed of time-of-flight and Thomson parabola spectrometers for simultaneous characterization of laser-driven ions.

    Science.gov (United States)

    Choi, I W; Kim, C M; Sung, J H; Yu, T J; Lee, S K; Kim, I J; Jin, Y-Y; Jeong, T M; Hafz, N; Pae, K H; Noh, Y-C; Ko, D-K; Yogo, A; Pirozhkov, A S; Ogura, K; Orimo, S; Sagisaka, A; Nishiuchi, M; Daito, I; Oishi, Y; Iwashita, Y; Nakamura, S; Nemoto, K; Noda, A; Daido, H; Lee, J

    2009-05-01

    An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), has been developed to measure energy spectra and to analyze species of laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate to compare the independently measured data and to combine advantages of each spectrometer. Real-time and shot-to-shot characterizations have been possible with the TOFS, and species of ions can be analyzed with the TPS. The two spectrometers show very good agreement of maximum proton energy even for a single laser shot. The composite ion spectrometer can provide two complementary spectra measured by TOFS with a large solid angle and TPS with a small one for the same ion source, which are useful to estimate precise total ion number and to investigate fine structure of energy spectrum at high energy depending on the detection position and solid angle. Advantage and comparison to other online measurement system, such as the TPS equipped with microchannel plate, are discussed in terms of overlay of ion species, high-repetition rate operation, detection solid angle, and detector characteristics of imaging plate.

  5. Advances in surface ion suppression from RILIS: Towards the Time-of-Flight Laser Ion Source (ToF-LIS)

    CERN Document Server

    Rothe, S; Crepieux, B; Day Goodacre, T; Fedosseev, V N; Giles, T; Marsh, B A; Ramos, J P; Rossel, R E

    2016-01-01

    We present results from the development towards the Time-of-Flight Laser Ion Source (ToF-LIS) aiming for the suppression of isobaric contaminants through fast beam gating. The capability to characterize high resistance ion sources has been successfully demonstrated. A ninefold selectivity gain has been achieved through suppression of surface ionized potassium, while maintaining >90% transmission for laser-ionized gallium using a thin wall graphite ionizer cavity combined with a fast beam gate. Initial results from the investigation of glassy carbon as a potential hot cavity ion source are presented. Power-cycle tests of a newly designed mount for fragile ion source cavities indicates its capability to survive the thermal stress expected during operation in an ISOLDE target unit. Finally, we introduce fast ion beam switching at a rate of 10 kHz using the ISOLDE ion beam switchyard as a new concept for ion beam distribution and conclude by highlighting the potential applications of this ion beam multiplexing te...

  6. Effect of surface-enhanced laser desorption/ionization time-of-flight mass spectrometry on identifing biomarkers of endometriosis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong; FENG Jie; CHANG Xiao-hong; LI Zhong-xing; WU Xiao-yi; CUI Heng

    2009-01-01

    Background Endometriosis is a common gynecological disease. This study aimed to screen proteins that were expressed differently in patients with endometriosis versus normal controls using proteomic techniques, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS).Methods Protein chip SELDI-TOF-MS combines the advantages of microarray and mass spectrometry, and can screen latent markers in sera of patients with endometriosis. Serum samples from patients and normal volunteers were analyzed by SELDI-TOF-MS.Results After comparing the serum protein spectra of 36 patients with 24 normal controls, 24 differently expressed potential biomarkers (P <0.01) were identified. Using Biomarker Pattern software, we established a tree model of the 60 serum protein spectra. When using the three biomarkers to classify the samples, the sensitivity for diagnosing endometriosis was 91.7%, specificity was 95.8%, and coincidence rate was 93.3%. Then we used serum samples from 12 patients and 8 normal controls to validate the tree model and report the sensitivity for diagnosing endometriosis was 91.7%, specificity was 75%, and coincidence rate was 85%.Conclusions SELDI-TOF-MS may be a useful tool in high-risk population screening for endometriosis. The identification and application of the biomarkers need to further study.

  7. Stopping force of Ti for 6 ⩽ Z ⩽ 29 ions measured by time of flight spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Msimanga, M. [Department of Physics, Tshwane University of Technology, Private X680, Pretoria 0001 (South Africa); Mtshali, C.B. [Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Pineda-Vargas, C.A. [Materials Research Department, iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Cape Town (South Africa)

    2015-04-15

    Accurate stopping force data is of vital importance in ion beam materials analysis using heavy ion beams. The predictive accuracy of theoretical and semi-empirical formulations can only be improved through continual validation of these codes by making available experimental data from a wide range of projectile-target combinations. In this work stopping force measurements of Ti for {sup 12}C, {sup 16}O, {sup 24}Mg, {sup 27}Al and {sup 63}Cu ions were carried out by heavy ion Time-of-Flight Elastic Recoil Detection (ToF-ERD) spectrometry and the results are compared with semi-empirical calculations by Ziegler’s Stopping and Range of Ions in Matter (SRIM-2010) code, and ab initio calculations by Grande and Schiewietz’s Convolution approximation for swift Particles (CasP 5.2) code. Both SRIM and CasP underestimate stopping in the energy range studied. SRIM predictions average within 10% of data and CasP calculations range within 5–25% of data.

  8. New Potential Biomarker for Methasterone Misuse in Human Urine by Liquid Chromatography Quadrupole Time of Flight Mass Spectrometry

    Science.gov (United States)

    Zhang, Jianli; Lu, Jianghai; Wu, Yun; Wang, Xiaobing; Xu, Youxuan; Zhang, Yinong; Wang, Yan

    2016-01-01

    In this study, methasterone urinary metabolic profiles were investigated by liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF-MS) in full scan and targeted MS/MS modes with accurate mass measurement. A healthy male volunteer was asked to take the drug and liquid–liquid extraction was employed to process urine samples. Chromatographic peaks for potential metabolites were hunted out with the theoretical [M − H]− as a target ion in a full scan experiment and actual deprotonated ions were studied in targeted MS/MS experiment. Fifteen metabolites including two new sulfates (S1 and S2), three glucuronide conjugates (G2, G6 and G7), and three free metabolites (M2, M4 and M6) were detected for methasterone. Three metabolites involving G4, G5 and M5 were obtained for the first time in human urine samples. Owing to the absence of helpful fragments to elucidate the steroid ring structure of methasterone phase II metabolites, gas chromatography mass spectrometry (GC-MS) was employed to obtain structural information of the trimethylsilylated phase I metabolite released after enzymatic hydrolysis and the potential structure was inferred using a combined MS method. Metabolite detection times were also analyzed and G2 (18-nor-17β-hydroxymethyl-2α, 17α-dimethyl-androst-13-en-3α-ol-ξ-O-glucuronide) was thought to be new potential biomarker for methasterone misuse which can be detected up to 10 days. PMID:27669235

  9. Readout strategy of an electro-optical coupled PET detector for time-of-flight PET/MRI

    Science.gov (United States)

    Bieniosek, M. F.; Olcott, P. D.; Levin, C. S.

    2013-10-01

    Combining PET with MRI in a single system provides clinicians with complementary molecular and anatomical information. However, existing integrated PET/MRI systems do not have time-of-flight (ToF) PET capabilities. This work describes an MRI-compatible front-end electronic system with ToF capabilities. The approach employs a fast arrival-time pickoff comparator to digitize the timing information, and a laser diode to drive a 10 m fiber-optic cable to optically transmit asynchronous timing information to a photodiode receiver readout system. The FWHM jitter of the comparator and this electo-optical link is 11.5 ps in response to a fast digital pulse. When configured with LYSO scintillation crystals and Hamamatsu MPPC silicon photo-multipliers the comparator and electro-optical link achieved a 511 keV coincidence time resolution of 254.7 ps +/- 8.0 ps FWHM with 3 × 3 × 20 mm3 crystals and 166.5 +/- 2.5 ps FWHM with 3 × 3 × 5 mm3 crystals.

  10. Advances in surface ion suppression from RILIS: Towards the Time-of-Flight Laser Ion Source (ToF-LIS)

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, S., E-mail: sebastian.rothe@cern.ch [CERN, Geneva (Switzerland); Catherall, R.; Crepieux, B. [CERN, Geneva (Switzerland); Day Goodacre, T. [CERN, Geneva (Switzerland); School of Physics and Astronomy, The University of Manchester, Manchester (United Kingdom); Fedosseev, V.N.; Giles, T.; Marsh, B.A. [CERN, Geneva (Switzerland); Ramos, J.P. [CERN, Geneva (Switzerland); Laboratory of Powder Technology, EPFL, Lausanne (Switzerland); Rossel, R.E. [CERN, Geneva (Switzerland); Institut für Physik, Johannes Gutenberg-Universität, Mainz (Germany); Faculty of Design, Computer Science and Media, Hochschule RheinMain, Wiesbaden (Germany)

    2016-06-01

    We present results from the development towards the Time-of-Flight Laser Ion Source (ToF-LIS) aiming for the suppression of isobaric contaminants through fast beam gating. The capability to characterize high resistance ion sources has been successfully demonstrated. A ninefold selectivity gain has been achieved through suppression of surface ionized potassium, while maintaining >90% transmission for laser-ionized gallium using a thin wall graphite ionizer cavity combined with a fast beam gate. Initial results from the investigation of glassy carbon as a potential hot cavity ion source are presented. Power-cycle tests of a newly designed mount for fragile ion source cavities indicates its capability to survive the thermal stress expected during operation in an ISOLDE target unit. Finally, we introduce fast ion beam switching at a rate of 10 kHz using the ISOLDE ion beam switchyard as a new concept for ion beam distribution and conclude by highlighting the potential applications of this ion beam multiplexing technique.

  11. New potential biomarkers for mesterolone misuse in human urine by liquid chromatography quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Lu, Jianghai; Fernández-Álvarez, María; Yang, Sheng; He, Genye; Xu, Youxuan; Aguilera, Rodigo

    2015-01-01

    In this paper, mesterolone metabolic profiles were investigated carefully. Mesterolone was administered to one healthy male volunteer. Urinary extracts were analyzed by liquid chromatography quadruple time-of-flight mass spectrometry (LC-QTOFMS) for the first time. Liquid-liquid extraction was applied to processing urine samples, and dilute-shoot analyses of intact metabolites were also presented. In LC-QTOFMS analysis, chromatographic peaks for potential metabolites were hunt down by using the theoretical [M-H](-) as target ions in full scan experiment, and their actual deprotonated ions were analyzed in targeted MS/MS mode. Ten metabolites including seven new sulfate and three glucuronide conjugates were found for mesterolone. Because of no useful fragment ion for structural elucidation, gas chromatography-mass spectrometry instrumentation was employed to obtain structural details of the trimethylsilylated phase I metabolite released after solvolysis. Thus, their potential structures were proposed particularly by a combined MS approach. All the metabolites were also evaluated in terms of how long they could be detected, and S1 (1α-methyl-5α-androst-3-one-17β-sulfate) together with S2 (1α-methyl-5α-androst-17-one-3β-sulfate) was detected up to 9 days after oral administration, which could be the new potential biomarkers for mesterolone misuse.

  12. Probing orientation of immobilized humanized anti-lysozyme variable fragment by time-of-flight secondary-ion mass spectrometry.

    Science.gov (United States)

    Baio, J E; Cheng, Fang; Ratner, Daniel M; Stayton, Patrick S; Castner, David G

    2011-04-01

    As methods to orient proteins are conceived, techniques must also be developed that provide an accurate characterization of immobilized protein orientation. In this study, X-ray photoelectron spectroscopy (XPS), surface plasmon resonance (SPR), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to probe the orientation of a surface immobilized variant of the humanized anti-lysozyme variable fragment (HuLys Fv, 26 kDa). This protein contained both a hexahistidine tag and a cysteine residue, introduced at opposite ends of the HuLys Fv, for immobilization onto nitrilotriacetic acid (NTA) and maleimide oligo(ethylene glycol) (MEG)-terminated substrates, respectively. The thiol group on the cysteine residue selectively binds to the MEG groups, while the his-tag selectively binds to the Ni-loaded NTA groups. XPS was used to monitor protein coverage on both surfaces by following the change in the nitrogen atomic %. SPR results showed a 10-fold difference in lysozyme binding between the two different HuLys Fv orientations. The ToF-SIMS data provided a clear differentiation between the two samples due to the intensity differences of secondary ions originating from asymmetrically located amino acids in HuLys Fv (histidine: 81, 82, and 110 m/z; phenylalanine: 120 and 131 m/z). An intensity ratio of the secondary ion peaks from the histidine and phenylalanine residues at either end of the protein was then calculated directly from the ToF-SIMS data. The 45% change in this ratio, observed between the NTA and MEG substrates with similar HuLys Fv surface coverages, indicates that the HuLys Fv fragment has opposite orientations on two different surfaces.

  13. Identification of molecules in graphite furnace by laser ionization time-of-flight mass spectrometry: sulfur and chlorine containing compounds

    CSIR Research Space (South Africa)

    Raseleka, RM

    2004-01-01

    Full Text Available sulfate, chlo- rides of sodium, potassium, caesium, magnesium, calcium and strontium were vaporized in the graphite furnace. The vapors Fig. 1 UV absorption spectra of MgSO4,H2SO4 and sulfur powder. :10.1039/b400792a J. Anal. At. Spectrom., 2004, 19, 899... acquisition stages are 5 and 6. Fig. 2 (a) Electrothermal vaporizer coupled to a time of flight mass spectrometer. (b). Reflectron type time of flight mass spectrometer. 900 J. Anal. At. Spectrom., 2004, 19, 899?905 of the laser (10 Hz), the signals shown...

  14. Development of a picosecond time-of-flight system in the ATLAS experiment

    CERN Document Server

    Grabas, Hervé

    In this thesis, we present a study of the sensitivity to Beyond Standard Model physics brought by the design and installation of picosecond time-of-flight detectors in the forward region of the ATLAS experiment at the LHC. The first part of the thesis present a study of the sensitivity to the quartic gauge anomalous coupling between the photon and the W boson, using exclusive WW pair production in ATLAS. The event selection is built considering the semi-leptonic decay of WW pair and the presence of the AFP detector in ATLAS. The second part gives a description of large area picosecond photo-detectors design and time reconstruction algorithms with a special care given to signal sampling and processing for precision timing.The third part presents the design of SamPic: a custom picosecond readout integrated circuit. At the end, its first results are reported, and in particular a world-class 5ps timing precision in measuring the delay between two fast pulses.

  15. Switching Transient Generation in Surface Interrogation Scanning Electrochemical Microscopy and Time-of-Flight Techniques.

    Science.gov (United States)

    Ahn, Hyun S; Bard, Allen J

    2015-12-15

    In surface interrogation scanning electrochemical microscopy (SI-SECM), fine and accurate control of the delay time between substrate generation and tip interrogation (tdelay) is crucial because tdelay defines the decay time of the reactive intermediate. In previous applications of the SI-SECM, the resolution in the control of tdelay has been limited to several hundreds of milliseconds due to the slow switching of the bipotentiostat. In this work, we have improved the time resolution of tdelay control up to ca. 1 μs, enhancing the SI-SECM to be competitive in the time domain with the decay of many reactive intermediates. The rapid switching SI-SECM has been implemented in a substrate generation-tip collection time-of-flight (SG-TC TOF) experiment of a solution redox mediator, and the results obtained from the experiment exhibited good agreement with that obtained from digital simulation. The reaction rate constant of surface Co(IV) on oxygen-evolving catalyst film, which was inaccessible thus far due to the lack of tdelay control, has been measured by the rapid switching SI-SECM.

  16. Development of a Portable Single Photon Ionization-Photoelectron Ionization Time-of-Flight Mass Spectrometer

    Directory of Open Access Journals (Sweden)

    Yunguang Huang

    2015-01-01

    Full Text Available A vacuum ultraviolet lamp based single photon ionization- (SPI- photoelectron ionization (PEI portable reflecting time-of-flight mass spectrometer (TOFMS was designed for online monitoring gas samples. It has a dual mode ionization source: SPI for analyte with ionization energy (IE below 10.6 eV and PEI for IE higher than 10.6 eV. Two kinds of sampling inlets, a capillary inlet and a membrane inlet, are utilized for high concentration and trace volatile organic compounds, respectively. A mass resolution of 1100 at m/z 64 has been obtained with a total size of 40 × 31 × 29 cm, the weight is 27 kg, and the power consumption is only 70 W. A mixture of benzene, toluene, and xylene (BTX, SO2, and discharging products of SF6 were used to test its performance, and the result showed that the limit of quantitation for BTX is as low as 5 ppbv (S/N = 10 : 1 with linear dynamic ranges greater than four orders of magnitude. The portable TOFMS was also evaluated by analyzing volatile organic compounds from wine and decomposition products of SF6 inside of a gas-insulated switchgear.

  17. Particle identification with the ALICE Time-Of-Flight detector at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Alici, A., E-mail: alici@bo.infn.it [Centro Fermi - Centro Studi e Ricerche e Museo Storico della Fisica “Enrico Fermi”, Rome (Italy); Sezione INFN, Bologna (Italy)

    2014-12-01

    High performance Particle Identification system (PID) is a distinguishing characteristic of the ALICE experiment at the CERN Large Hadron Collider (LHC). Charged particles in the intermediate momentum range are identified in ALICE by the Time-Of-Flight (TOF) detector. The TOF exploits the Multi-gap Resistive Plate Chamber (MRPC) technology, capable of an intrinsic time resolution at the level of few tens of ps with an overall efficiency close to 100% and a large operation plateau. The full system is made of 1593 MRPC chambers with a total area of 141 m{sup 2}, covering the pseudorapidity interval [−0.9,+0.9] and the full azimuthal angle. The ALICE TOF system has shown very stable operation during the first 3 years of collisions at the LHC. In this paper a summary of the system performance as well as main results with data from collisions will be reported. - Highlights: • We report the performance of large area, small granularity ALICE TOF system based on MRPC technology. • Description and performance of PID analysis with the TOF are reported. • A non-exhaustive list of physics analyses, where the TOF PID is used, is given.

  18. A laser diode based system for calibration of fast time-of-flight detectors

    CERN Document Server

    Bonesini, M; deBari, A; Rossella, M

    2016-01-01

    A system based on commercially available items, such as a laser diode, emitting in the visible range $\\sim 400$ nm,and multimode fiber patches, fused fiber splitters and optical switches may be assembled,for time calibration of multi-channels time-of-flight (TOF) detectors with photomultipliers' (PMTs') readout. As available laser diode sources have unfortunately limited peak power, the main experimental problem is the tight light power budget of such a system. In addition, while the technology for fused fiber splitters is common in the Telecom wavelength range ($\\lambda \\sim 850, 1300-1500$ nm), it is not easily available in the visible one. Therefore, extensive laboratory tests had to be done on purpose, to qualify the used optical components, and a full scale timing calibration prototype was built. Obtained results show that with such a system, a calibration resolution ($\\sigma$) in the range 20-30 ps may be within reach. Therefore, fast multi-channels TOF detectors, with timing resolutions in the range 50...

  19. Timing and position response of a block detector for fast neutron time-of-flight imaging

    Science.gov (United States)

    Laubach, M. A.; Hayward, J. P.; Zhang, X.; Cates, J. W.

    2014-11-01

    Our research effort seeks to improve the spatial and timing performance of a block detector made of a pixilated plastic scintillator (EJ-200), first demonstrated as part of Oak Ridge National Laboratory's Advanced Portable Neutron Imaging System. Improvement of the position and time response is necessary to achieve better resolution and contrast in the images of shielded special nuclear material. Time-of-flight is used to differentiate between gamma and different sources of neutrons (e.g., transmission and fission neutrons). Factors limiting the timing and position performance of the neutron detector have been revealed through simulations and measurements. Simulations have suggested that the degradation in the ability to resolve pixels in the neutron detector is due to those interactions occurring near the light guide. The energy deposition within the neutron detector is shown to affect position performance and imaging efficiency. This examination details how energy cuts improve the position performance and degrade the imaging efficiency. Measurements have shown the neutron detector to have a timing resolution of σ=238 ps. The majority of this timing uncertainty is from the depth-of-interaction (DOI) of the neutron which is confirmed by simulations and analytical calculations.

  20. Analysis of the neutron time-of-flight spectra from inertial confinement fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hatarik, R., E-mail: hatarik1@llnl.gov; Sayre, D. B.; Caggiano, J. A.; Phillips, T.; Eckart, M. J.; Bond, E. J.; Cerjan, C.; Grim, G. P.; Hartouni, E. P.; Mcnaney, J. M.; Munro, D. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Knauer, J. P. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2015-11-14

    Neutron time-of-flight diagnostics have long been used to characterize the neutron spectrum produced by inertial confinement fusion experiments. The primary diagnostic goals are to extract the d + t → n + α (DT) and d + d → n + {sup 3}He (DD) neutron yields and peak widths, and the amount DT scattering relative to its unscattered yield, also known as the down-scatter ratio (DSR). These quantities are used to infer yield weighted plasma conditions, such as ion temperature (T{sub ion}) and cold fuel areal density. We report on novel methodologies used to determine neutron yield, apparent T{sub ion}, and DSR. These methods invoke a single temperature, static fluid model to describe the neutron peaks from DD and DT reactions and a spline description of the DT spectrum to determine the DSR. Both measurements are performed using a forward modeling technique that includes corrections for line-of-sight attenuation and impulse response of the detection system. These methods produce typical uncertainties for DT T{sub ion} of 250 eV, 7% for DSR, and 9% for the DT neutron yield. For the DD values, the uncertainties are 290 eV for T{sub ion} and 10% for the neutron yield.

  1. The Large-Area Time-Of-Flight (TOF) Upgrade for the STAR Detector

    Science.gov (United States)

    Llope, W. J.

    2009-03-01

    The STAR experiment at RHIC concentrates on the tracking of charged hadrons via ionization in gas- and silicon-based detectors, and the detection of electrons and photons via calorimetry, in a wide and azimuthally complete acceptance that's unique at RHIC. STAR's ability to directly identify the tracked charged hadrons is however limited to low momenta. Approximately half of the charged particles in the event at higher momenta cannot be directly identified, which hampers the physics reach of STAR in a number of key areas. To address this blind spot, STAR is presently constructing a large-area (˜50 m2) Time-Of-Flight (TOF) system. This system is based on Multi-gap Resistive Plate Chambers (MRPCs). Prototype TOF systems based on this technology were operated in STAR during RHIC Runs 3 through 6, and the first 5 final-system trays were operated in the recent RHIC Run 8. A new "start detector" for this system has also been constructed and operated in STAR. The performance of these detectors in STAR, and an update on the status of the construction of the full system, is discussed.

  2. Quantification of sterol lipids in plants by quadrupole time-of-flight mass spectrometry

    Science.gov (United States)

    Wewer, Vera; Dombrink, Isabel; vom Dorp, Katharina; Dörmann, Peter

    2011-01-01

    Glycerolipids, sphingolipids, and sterol lipids constitute the major lipid classes in plants. Sterol lipids are composed of free and conjugated sterols, i.e., sterol esters, sterol glycosides, and acylated sterol glycosides. Sterol lipids play crucial roles during adaption to abiotic stresses and plant-pathogen interactions. Presently, no comprehensive method for sterol lipid quantification in plants is available. We used nanospray ionization quadrupole-time-of-flight mass spectrometry (Q-TOF MS) to resolve and identify the molecular species of all four sterol lipid classes from Arabidopsis thaliana. Free sterols were derivatized with chlorobetainyl chloride. Sterol esters, sterol glycosides, and acylated sterol glycosides were ionized as ammonium adducts. Quantification of molecular species was achieved in the positive mode after fragmentation in the presence of internal standards. The amounts of sterol lipids quantified by Q-TOF MS/MS were validated by comparison with results obtained with TLC/GC. Quantification of sterol lipids from leaves and roots of phosphate-deprived A. thaliana plants revealed changes in the amounts and molecular species composition. The Q-TOF method is far more sensitive than GC or HPLC. Therefore, Q-TOF MS/MS provides a comprehensive strategy for sterol lipid quantification that can be adapted to other tandem mass spectrometers. PMID:21382968

  3. Time of flight MR angiography using 2DFT-fast spoiled GRASS technique

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Hideshi; Matsushita, Masaki (Osaka Teishin Hospital (Japan)); Murakami, Takamichi (and others)

    1994-01-01

    MR angiography using a fast spoiled GRASS (FSPGR) technique was performed in 24 patients with portal hypertension and seven normal subjects on a 1.5-T MR unit (GE Signa). The results were compared to those for conventional 2D time-of-flight MR angiography obtained with a spoiled GRASS (SPGR) technique (40/12/25, TR/TE/flip angle). Twenty five to 30 sections were obtained by FSPGR (8.1/3.1/30 TR/TE/flip angel) within a 25-30 second single breath-hold technique. SPGR images were obtained with repeated breath-holds within 20-30 seconds. The projection MR angiography was reconstructed from these images with maximum intensity projection technique. Signal-to-noise ratios for FSPGR images that were measured on the vessel and the liver were significantly superior to those for SPGR images (P<0.01). Anatomical details such as portal veins or other vessel were better delineated with FSPGR than with SPGR. MR angiography using a FSPGR is useful in evaluating the portal veins and collateral vessels in patients with portal hypertention. (author).

  4. AMOR – the time-of-flight neutron reflectometer at SINQ/PSI

    Indian Academy of Sciences (India)

    Mukul Gupta; T Gutberlet; J Stahn; P Keller; D Clemens

    2004-07-01

    The apparatus for multioptional reflectometry (AMOR) at SINQ/PSI is a versatile reflectometer operational in the time-of-flight (TOF) mode (in a wavelength range of 0.15 nm > > 1.3 nm) as well as in the monochromatic ( - 2) mode with both polarized and unpolarized neutrons. AMOR is designed to perform reflectometry measurements in horizontal sample-plane geometry which allows studying both solid–liquid and liquid–liquid interfaces. A pulsed cold neutron beam from the end position of the neutron guide is produced by a dual-chopper system (side-by-side) having two windows at 180° and rotatable with a maximum frequency of 200 Hz. In the TOF mode, the chopper frequency, width of the gating window and the chopper–detector distance can be selected independently providing a wide range of -resolution ( / = 1–10%). Remanent FeCoV/Ti : N supermirrors are used as polarizer/analyzer with a polarization efficiency of ∼ 97%. For the monochromatic wavelength mode, a Ni/Ti multilayer is used as a monochromator, giving ∼ 50% reflectivity at a wavelength of 0.47 nm. In the present work, a detailed description of the instrument and setting-up of the polarization option is described. Results from some of the recent studies with polarized neutrons and measurements on liquid surfaces are presented.

  5. Impulse responses of visible phototubes used in National Ignition Facility neutron time of flight diagnostics

    Science.gov (United States)

    Datte, P. S.; Eckart, M.; Moore, A. S.; Thompson, W.; Vergel de Dios, G.

    2016-11-01

    Neutron-induced visible scintillation in neutron time of flight (NToF) diagnostics at the National Ignition Facility (NIF) is measured with 40 mm single stage micro-channel plate photomultipliers and a 40 mm vacuum photodiode, outside the neutron line of sight. In NIF experiments with 14 MeV neutron yields above Y > 10 × 1015 these tubes are configured to deliver of order 1 nC of charge in the nominally 5 ns NToF into a 50 Ω load. We have examined a number of 40 mm tubes manufactured by Photek Ltd. of St. Leonards on Sea, UK, to determine possible changes in the instrument impulse response as a function of signal charge delivered in 1 ns. Precision NToF measurements at approximately 20 m require that we characterize changes in the impulse response moments to <40 ps for the first central moment and ˜2% rms for the square root of the second central moment with ˜500 ps value. Detailed results are presented for three different diode configurations.

  6. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    Energy Technology Data Exchange (ETDEWEB)

    Estrade, Alfredo [National Superconducting Cyclotron Laboratory (NSCL); Matos, M. [Louisiana State University; Schatz, Hendrik [Michigan State University, East Lansing; Amthor, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Bazin, D. [National Superconducting Cyclotron Laboratory (NSCL); Beard, Mary [University of Notre Dame, IN; Becerril, A. [National Superconducting Cyclotron Laboratory (NSCL); Brown, Edward [Michigan State University, East Lansing; Elliot, T [National Superconducting Cyclotron Laboratory (NSCL); Gade, A. [National Superconducting Cyclotron Laboratory (NSCL); Galaviz, D. [National Superconducting Cyclotron Laboratory (NSCL); George, S. [National Superconducting Cyclotron Laboratory (NSCL); Gupta, Sanjib [Indian Institute of Technology, Kanpur; Hix, William Raphael [ORNL; Lau, Rita [National Superconducting Cyclotron Laboratory (NSCL); Moeller, Peter [Los Alamos National Laboratory (LANL); Pereira, J. [National Superconducting Cyclotron Laboratory (NSCL); Portillo, M. [National Superconducting Cyclotron Laboratory (NSCL); Rogers, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Shapira, Dan [ORNL; Smith, E. [Ohio State University; Stolz, A. [Michigan State University, East Lansing; Wallace, M. [Los Alamos National Laboratory (LANL); Wiescher, Michael [University of Notre Dame, IN

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Supercon- ducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the Sc Ni element range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of 61V, 63Cr, 66Mn, and 74Ni were measured for the first time with mass excesses of 30.510(890) MeV, 35.280(650) MeV, 36.900(790) MeV, and 49.210(990) MeV, respectively. With the measurement of the 66Mn mass, the location of the two dominant heat sources in the outer crust of accreting neutron stars, which exhibit so called superbursts, is now experimentally constrained. We find that the location of the 66Fe 66Mn electron capture transition occurs sig- nificantly closer to the surface than previously assumed because our new experimental Q-value is 2.1 MeV smaller than predicted by the FRDM mass model. The results also provide new insights into the structure of neutron-rich nuclei around N = 40.

  7. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    CERN Document Server

    Estrade, A; Schatz, H; Amthor, A M; Bazin, D; Beard, M; Becerril, A; Brown, E F; Cyburt, R; Elliot, T; Gade, A; Galaviz, D; George, S; Gupta, S S; Hix, W R; Lau, R; Lorusso, G; Moller, P; Pereira, J; Portillo, M; Rogers, A M; Shapira, D; Smith, E; Stolz, A; Wallace, M; Wiescher, M

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Superconducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the scandium -- nickel range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of $^{61}${V}, $^{63}${Cr}, $^{66}${Mn}, and $^{74}${Ni} were measured for the first time with mass excesses of $-30.510(890)$ MeV, $-35.280(650)$ MeV, $-36.900(790)$ MeV, and $-49.210(990)$ MeV, respectively. With the measurement of the $^{66}$Mn mass, the locations of the two dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit superbursts are now experimentally constrained. We find that the location of the $^{66}$Fe$\\rightarrow^{66}$Mn electron capture transition occurs signi...

  8. Simultaneous reconstruction of activity and attenuation in time-of-flight PET.

    Science.gov (United States)

    Rezaei, Ahmadreza; Defrise, Michel; Bal, Girish; Michel, Christian; Conti, Maurizio; Watson, Charles; Nuyts, Johan

    2012-12-01

    In positron emission tomography (PET) and single photon emission tomography (SPECT), attenuation correction is necessary for quantitative reconstruction of the tracer distribution. Previously, several attempts have been made to estimate the attenuation coefficients from emission data only. These attempts had limited success, because the problem does not have a unique solution, and severe and persistent "cross-talk" between the estimated activity and attenuation distributions was observed. In this paper, we show that the availability of time-of-flight (TOF) information eliminates the cross-talk problem by destroying symmetries in the associated Fisher information matrix. We propose a maximum-a-posteriori reconstruction algorithm for jointly estimating the attenuation and activity distributions from TOF PET data. The performance of the algorithm is studied with 2-D simulations, and further illustrated with phantom experiments and with a patient scan. The estimated attenuation image is robust to noise, and does not suffer from the cross-talk that was observed in non-TOF PET. However, some constraining is still mandatory, because the TOF data determine the attenuation sinogram only up to a constant offset.

  9. Defocus Deblurring and Superresolution for Time-of-Flight Depth Cameras

    KAUST Repository

    Xiao, Lei

    2015-06-07

    Continuous-wave time-of-flight (ToF) cameras show great promise as low-cost depth image sensors in mobile applications. However, they also suffer from several challenges, including limited illumination intensity, which mandates the use of large numerical aperture lenses, and thus results in a shallow depth of field, making it difficult to capture scenes with large variations in depth. Another shortcoming is the limited spatial resolution of currently available ToF sensors. In this paper we analyze the image formation model for blurred ToF images. By directly working with raw sensor measurements but regularizing the recovered depth and amplitude images, we are able to simultaneously deblur and super-resolve the output of ToF cameras. Our method outperforms existing methods on both synthetic and real datasets. In the future our algorithm should extend easily to cameras that do not follow the cosine model of continuous-wave sensors, as well as to multi-frequency or multi-phase imaging employed in more recent ToF cameras.

  10. Depth Errors Analysis and Correction for Time-of-Flight (ToF) Cameras.

    Science.gov (United States)

    He, Ying; Liang, Bin; Zou, Yu; He, Jin; Yang, Jun

    2017-01-05

    Time-of-Flight (ToF) cameras, a technology which has developed rapidly in recent years, are 3D imaging sensors providing a depth image as well as an amplitude image with a high frame rate. As a ToF camera is limited by the imaging conditions and external environment, its captured data are always subject to certain errors. This paper analyzes the influence of typical external distractions including material, color, distance, lighting, etc. on the depth error of ToF cameras. Our experiments indicated that factors such as lighting, color, material, and distance could cause different influences on the depth error of ToF cameras. However, since the forms of errors are uncertain, it's difficult to summarize them in a unified law. To further improve the measurement accuracy, this paper proposes an error correction method based on Particle Filter-Support Vector Machine (PF-SVM). Moreover, the experiment results showed that this method can effectively reduce the depth error of ToF cameras to 4.6 mm within its full measurement range (0.5-5 m).

  11. High Performance Bilinear Differential Preamplifier for BESIII Time-of-Flight System

    Institute of Scientific and Technical Information of China (English)

    Lee Yusheng; Xian Ze; An Qi

    2005-01-01

    A time-of-flight (TOF) detector has been used in the BESⅢ experiment to provide charged particle identification. In this paper, we present a novel high performance differential amplifier, which has been designed for amplifying the signals from the detectors. The preamplifier can amplify differential signals, which can help to eliminate the common mode pickup, and increase the signal-to-noise ratio (SNR). Bilinear gain is one of the features of this preamplifier, which greatly increases the dynamic range and avoids the dead time of the preamplifier. In order to describe the bilinear gain, a 4-parameter function is developed. And this 4-parameter function can also be used in the calibration of the time walk caused by the amplitude due to the bilinear gain. The preamplifier has a gain about 10 V/V with a small signal and about 1.0 V/V with a large signal. The rise time of the preamp is less than 2 ns.

  12. Experimental evaluation of a simple lesion detection task with time-of-flight PET

    Energy Technology Data Exchange (ETDEWEB)

    Surti, S; Karp, J S [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States)], E-mail: surti@mail.med.upenn.edu, E-mail: joelkarp@mail.med.upenn.edu

    2009-01-21

    A new generation of high-performance, time-of-flight (TOF) PET scanners have recently been developed. In earlier works, the gain with TOF information was derived as a reduction of noise in the reconstructed image, or essentially a gain in scanner sensitivity. These derivations were applicable to analytical reconstruction techniques and 2D PET imaging. In this work, we evaluate the gain measured in the clinically relevant task of lesion detection with TOF information in fully 3D PET scanners using iterative reconstruction algorithms. We performed measurements in a fully 3D TOF PET scanner using spherical lesions in uniform, cylindrical phantom. Lesion detectability was estimated for 10 mm diameter lesions using a non-prewhitening matched filter signal-to-noise-ratio (NPW SNR) as the metric. Our results show that the use of TOF information leads to increased lesion detectability, which is achieved with less number of iterations of the reconstruction algorithm. These phantom results indicate that clinically, TOF PET will allow reduced scan times and improved lesion detectability, especially in large patients.

  13. Diffuse mirrors: 3D reconstruction from diffuse indirect illumination using inexpensive time-of-flight sensors

    KAUST Repository

    Heide, Felix

    2014-06-01

    The functional difference between a diffuse wall and a mirror is well understood: one scatters back into all directions, and the other one preserves the directionality of reflected light. The temporal structure of the light, however, is left intact by both: assuming simple surface reflection, photons that arrive first are reflected first. In this paper, we exploit this insight to recover objects outside the line of sight from second-order diffuse reflections, effectively turning walls into mirrors. We formulate the reconstruction task as a linear inverse problem on the transient response of a scene, which we acquire using an affordable setup consisting of a modulated light source and a time-of-flight image sensor. By exploiting sparsity in the reconstruction domain, we achieve resolutions in the order of a few centimeters for object shape (depth and laterally) and albedo. Our method is robust to ambient light and works for large room-sized scenes. It is drastically faster and less expensive than previous approaches using femtosecond lasers and streak cameras, and does not require any moving parts.

  14. Shock tube/time-of-flight mass spectrometer for high temperature kinetic studies.

    Science.gov (United States)

    Tranter, Robert S; Giri, Binod R; Kiefer, John H

    2007-03-01

    A shock tube (ST) with online, time-of-flight mass spectrometric (TOF-MS) detection has been constructed for the study of elementary reactions at high temperature. The ST and TOF-MS are coupled by a differentially pumped molecular beam sampling interface, which ensures that the samples entering the TOF-MS are not contaminated by gases drawn from the cold end wall thermal boundary layer in the ST. Additionally, the interface allows a large range of postshock pressures to be used in the shock tube while maintaining high vacuum in the TOF-MS. The apparatus and the details of the sampling system are described along with an analysis in which cooling of the sampled gases and minimization of thermal boundary layer effects are discussed. The accuracy of kinetic measurements made with the apparatus has been tested by investigating the thermal unimolecular dissociation of cyclohexene to ethylene and 1,3-butadiene, a well characterized reaction for which considerable literature data that are in good agreement exist. The experiments were performed at nominal reflected shock wave pressures of 600 and 1300 Torr, and temperatures ranging from 1260 to 1430 K. The rate coefficients obtained are compared with the earlier shock tube studies and are found to be in very good agreement. As expected no significant difference is observed in the rate constant between pressures of 600 and 1300 Torr.

  15. Towards self-triggered digitization and data readout in the CBM time-of-flight system

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Christian; Herrmann, Norbert [Physikalisches Institut und Fakultaet fuer Physik und Astronomie, Ruprecht-Karls-Universitaet Heidelberg, 69120 Heidelberg (Germany); Collaboration: CBM-Collaboration

    2015-07-01

    The design goal of the future Compressed Baryonic Matter (CBM) experiment is to measure rare probes of dense strongly interacting matter with an unprecedented accuracy. Target interaction rates of up to 10 MHz for heavy systems like Au+Au and the need to identify experimental signatures of probes like multi-strange hyperons in the online data stream place challenging demands on the experiment's data acquisition system. Each detector subsystem in CBM implements a self-triggered digitization and readout chain fitted to the respective front-end electronics sending continuous data streams to a high-performance computing farm called the First-Level Event Selector (FLES). Here, events are reconstructed online to identify the physically most interesting ones as only a fraction of the enormous data rate (up to 1 TB/s) can be stored permanently for later offline analysis. The time-of-flight (TOF) wall of CBM is composed of high-resolution timing multi-gap resistive plate chambers (MRPCs) which are estimated to deliver signal rates of up to 500 kHz per electronics channel. Prototypical readout schemes currently under test which are able to transport this high payload are presented, and an outline towards inclusion in the FLES network is given.

  16. Depth Errors Analysis and Correction for Time-of-Flight (ToF) Cameras

    Science.gov (United States)

    He, Ying; Liang, Bin; Zou, Yu; He, Jin; Yang, Jun

    2017-01-01

    Time-of-Flight (ToF) cameras, a technology which has developed rapidly in recent years, are 3D imaging sensors providing a depth image as well as an amplitude image with a high frame rate. As a ToF camera is limited by the imaging conditions and external environment, its captured data are always subject to certain errors. This paper analyzes the influence of typical external distractions including material, color, distance, lighting, etc. on the depth error of ToF cameras. Our experiments indicated that factors such as lighting, color, material, and distance could cause different influences on the depth error of ToF cameras. However, since the forms of errors are uncertain, it’s difficult to summarize them in a unified law. To further improve the measurement accuracy, this paper proposes an error correction method based on Particle Filter-Support Vector Machine (PF-SVM). Moreover, the experiment results showed that this method can effectively reduce the depth error of ToF cameras to 4.6 mm within its full measurement range (0.5–5 m). PMID:28067767

  17. Liquid chromatography quadrupole time-of-flight mass spectrometry selective determination of ochratoxin A in wine.

    Science.gov (United States)

    Rodríguez-Cabo, T; Rodríguez, I; Ramil, M; Cela, R

    2016-05-15

    The performance of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for ochratoxin A (OTA) determination in wine is evaluated for the first time. Sample preparation was optimized to obtain quantitative recoveries at the same time that the efficiency of electrospray ionization (ESI) remained unaltered between sample extracts and calibration standards. Under final conditions, samples (20 mL) were concentrated using a reversed-phase solid-phase extraction (SPE) cartridge, followed by OTA elution with 1 mL of ethyl acetate. The absolute recoveries of the method, established against calibration standards, were 91-121% and 90-113% (without and with internal standard correction, respectively), for wines fortified at 3 concentration levels. The attained LOQ (0.05 ng mL(-1)) remained below the maximum permitted OTA concentration (2 ng mL(-1)) in dry wines. The method was applied to different samples, with OTA being found in some dessert wines at concentrations below 1 ng mL(-1). The ethyl ester of OTA (OTC) could be identified in the same wine samples from its accurate full product ion spectra.

  18. A time-of-flight detector for thermal neutrons from radiotherapy Linacs

    Science.gov (United States)

    Conti, V.; Bartesaghi, G.; Bolognini, D.; Mascagna, V.; Perboni, C.; Prest, M.; Scazzi, S.; Mozzanica, A.; Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A.; Giannini, G.; Vallazza, E.

    2007-10-01

    Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a 10B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (>5×108 n cm-2 s-1) with the correct energy spectrum (neutron energy reactors. The INFN PhoNeS (Photo Neutron Source) project is trying to produce such a neutron beam with standard radiotherapy Linacs, maximizing with a dedicated photo-neutron converter the neutrons produced by Giant Dipole Resonance by a high energy ( >8 MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation.

  19. Photo-Detectors for Time of Flight Positron Emission Tomography (ToF-PET

    Directory of Open Access Journals (Sweden)

    Craig S. Levin

    2010-11-01

    Full Text Available We present the most recent advances in photo-detector design employed in time of flight positron emission tomography (ToF-PET. PET is a molecular imaging modality that collects pairs of coincident (temporally correlated annihilation photons emitted from the patient body. The annihilation photon detector typically comprises a scintillation crystal coupled to a fast photo-detector. ToF information provides better localization of the annihilation event along the line formed by each detector pair, resulting in an overall improvement in signal to noise ratio (SNR of the reconstructed image. Apart from the demand for high luminosity and fast decay time of the scintillation crystal, proper design and selection of the photo-detector and methods for arrival time pick-off are a prerequisite for achieving excellent time resolution required for ToF-PET. We review the two types of photo-detectors used in ToF-PET: photomultiplier tubes (PMTs and silicon photo-multipliers (SiPMs with a special focus on SiPMs.

  20. A laser diode based system for calibration of fast time-of-flight detectors

    Science.gov (United States)

    Bertoni, R.; Bonesini, M.; de Bari, A.; Rossella, M.

    2016-05-01

    A system based on commercially available items, such as a laser diode, emitting in the visible range ~ 400 nm, and multimode fiber patches, fused fiber splitters and optical switches may be assembled, for time calibration of multi-channels time-of-flight (TOF) detectors with photomultipliers' (PMTs') readout. As available laser diode sources have unfortunately limited peak power, the main experimental problem is the tight light power budget of such a system. In addition, while the technology for fused fiber splitters is common in the Telecom wavelength range (λ ~ 850, 1300-1500 nm), it is not easily available in the visible one. Therefore, extensive laboratory tests had to be done on purpose, to qualify the used optical components, and a full scale timing calibration prototype was built. Obtained results show that with such a system, a calibration resolution (σ) in the range 20-30 ps may be within reach. Therefore, fast multi-channels TOF detectors, with timing resolutions in the range 50-100 ps, may be easily calibrated in time. Results on tested optical components may be of interest also for time calibration of different light detection systems based on PMTs, as the ones used for detection of the vacuum ultraviolet scintillation light emitted by ionizing particles in large LAr TPCs.

  1. Time-of-Flight Mass Measurements for Nuclear Processes in Neutron Star Crusts

    Science.gov (United States)

    Estradé, A.; Matoš, M.; Schatz, H.; Amthor, A. M.; Bazin, D.; Beard, M.; Becerril, A.; Brown, E. F.; Cyburt, R.; Elliot, T.; Gade, A.; Galaviz, D.; George, S.; Gupta, S. S.; Hix, W. R.; Lau, R.; Lorusso, G.; Möller, P.; Pereira, J.; Portillo, M.; Rogers, A. M.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, M.

    2011-10-01

    We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of V61, Cr63, Mn66, and Ni74 measured for the first time with mass excesses of -30.510(890)MeV, -35.280(650)MeV, -36.900(790)MeV, and -49.210(990)MeV, respectively. With these results the locations of the dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit super bursts are now experimentally constrained. We find the experimental Q value for the Fe66→Mn66 electron capture to be 2.1 MeV (2.6σ) smaller than predicted, resulting in the transition occurring significantly closer to the neutron star surface.

  2. A 3D Scanning Device for Architectural Relieves Based on Time-Of-Flight Technology

    Science.gov (United States)

    Gambino, M. C.; Fontana, R.; Gianfrate, G.; Greco, M.; Marras, L.; Materazzi, M.; Pampaloni, E.; Pezzati, L.

    In this work we present the results of some architectural and archaeological relieves realized by means of a Time-Of-Flight (TOF) laser scanner developed by the Art Diagnostic Group of Istituto Nazionale di Ottica Applicata — INOA (the National Institute of Applied Optics). The instrument is composed of a commercial distance meter mounted on a high precision scanning system, and is equipped with a tripod for total-stations. The device was projected in order to have the following characteristics: reliability, good accuracy and compatibility to other systems. For Cultural Heritage applications it is important to integrate the data acquired with different instruments, but a problem met with many commercial systems is the lack of compatibility with classic survey methodologies. Moreover, superimposition of results from different techniques is possible only if the output is metrically correct. Up to now, the realization of accurate 3D models of buildings was a prerogative of the photogrammetric devices, but the recent progress in opto-electronic technology and 3D software of analysis made possible the production of accurate 3D models. Laser scanning has the main advantage of allowing the acquisition of dense data sampling with high accuracy and high speed.

  3. Photo-Detectors for Time of Flight Positron Emission Tomography (ToF-PET)

    Science.gov (United States)

    Spanoudaki, Virginia Ch.; Levin⋆, Craig S.

    2010-01-01

    We present the most recent advances in photo-detector design employed in time of flight positron emission tomography (ToF-PET). PET is a molecular imaging modality that collects pairs of coincident (temporally correlated) annihilation photons emitted from the patient body. The annihilation photon detector typically comprises a scintillation crystal coupled to a fast photo-detector. ToF information provides better localization of the annihilation event along the line formed by each detector pair, resulting in an overall improvement in signal to noise ratio (SNR) of the reconstructed image. Apart from the demand for high luminosity and fast decay time of the scintillation crystal, proper design and selection of the photo-detector and methods for arrival time pick-off are a prerequisite for achieving excellent time resolution required for ToF-PET. We review the two types of photo-detectors used in ToF-PET: photomultiplier tubes (PMTs) and silicon photo-multipliers (SiPMs) with a special focus on SiPMs. PMID:22163482

  4. LSO background radiation as a transmission source using time of flight.

    Science.gov (United States)

    Rothfuss, Harold; Panin, Vladimir; Moor, Andrew; Young, John; Hong, Inki; Michel, Christian; Hamill, James; Casey, Michael

    2014-09-21

    LSO scintillators (Lu2Sio5:Ce) have a background radiation which originates from the isotope Lu-176 that is present in natural occurring lutetium. The decay that occurs in this isotope is a beta decay that is in coincidence with cascade gamma emissions with energies of 307,202 and 88 keV. The coincidental nature of the beta decay with the gamma emissions allow for separation of emission data originating from a positron annihilation event from transmission type data from the Lu-176 beta decay. By using the time of flight information, and information of the chord length between two LSO pixels in coincidence as a result of a beta emission and emitted gamma, a second time window can be set to observe transmission events simultaneously to emission events. Using the time when the PET scanner is not actively acquiring positron emission data, a continuous blank can be acquired and used to reconstruct a transmission image. With this blank and the measured transmission data, a transmission image can be reconstructed. This reconstructed transmission image can be used to perform emission data corrections such as attenuation correction and scatter corrections or starting images for algorithms that estimate emission and attenuation simultaneously. It is observed that the flux of the background activity is high enough to create useful transmission images with an acquisition time of 10 min.

  5. Crystal timing offset calibration method for time of flight PET scanners

    Science.gov (United States)

    Ye, Jinghan; Song, Xiyun

    2016-03-01

    In time-of-flight (TOF) positron emission tomography (PET), precise calibration of the timing offset of each crystal of a PET scanner is essential. Conventionally this calibration requires a specially designed tool just for this purpose. In this study a method that uses a planar source to measure the crystal timing offsets (CTO) is developed. The method uses list mode acquisitions of a planar source placed at multiple orientations inside the PET scanner field-of-view (FOV). The placement of the planar source in each acquisition is automatically figured out from the measured data, so that a fixture for exactly placing the source is not required. The expected coincidence time difference for each detected list mode event can be found from the planar source placement and the detector geometry. A deviation of the measured time difference from the expected one is due to CTO of the two crystals. The least squared solution of the CTO is found iteratively using the list mode events. The effectiveness of the crystal timing calibration method is evidenced using phantom images generated by placing back each list mode event into the image space with the timing offset applied to each event. The zigzagged outlines of the phantoms in the images become smooth after the crystal timing calibration is applied. In conclusion, a crystal timing calibration method is developed. The method uses multiple list mode acquisitions of a planar source to find the least squared solution of crystal timing offsets.

  6. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams

    Energy Technology Data Exchange (ETDEWEB)

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M.; Kong, Wei, E-mail: wei.kong@oregonstate.edu [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)

    2015-08-15

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He{sub 2}{sup +} and He{sub 4}{sup +}, which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl{sub 4} doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He){sub n}C{sup +}, (He){sub n}Cl{sup +}, and (He){sub n}CCl{sup +}. Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  7. Photo-detectors for time of flight positron emission tomography (ToF-PET).

    Science.gov (United States)

    Spanoudaki, Virginia Ch; Levin, Craig S

    2010-01-01

    We present the most recent advances in photo-detector design employed in time of flight positron emission tomography (ToF-PET). PET is a molecular imaging modality that collects pairs of coincident (temporally correlated) annihilation photons emitted from the patient body. The annihilation photon detector typically comprises a scintillation crystal coupled to a fast photo-detector. ToF information provides better localization of the annihilation event along the line formed by each detector pair, resulting in an overall improvement in signal to noise ratio (SNR) of the reconstructed image. Apart from the demand for high luminosity and fast decay time of the scintillation crystal, proper design and selection of the photo-detector and methods for arrival time pick-off are a prerequisite for achieving excellent time resolution required for ToF-PET. We review the two types of photo-detectors used in ToF-PET: photomultiplier tubes (PMTs) and silicon photo-multipliers (SiPMs) with a special focus on SiPMs.

  8. Development of a portable time-of-flight membrane inlet mass spectrometer for environmental analysis

    Science.gov (United States)

    White, A. J.; Blamire, M. G.; Corlett, C. A.; Griffiths, B. W.; Martin, D. M.; Spencer, S. B.; Mullock, S. J.

    1998-02-01

    The benefits of on-site analysis of environmental pollutants are well known, with such techniques increasing sample throughput and reducing the overall cost of pollution level monitoring. This article describes a transportable time-of-flight (TOF) mass spectrometer, based upon a converging, annular TOF (CAT) arrangement. The instrument, the transportable CAT or T-CAT is battery powered and self-contained. The vacuum chamber is never vented and is kept at a very low pressure, even during analysis. Sample gases are admitted to the mass spectrometer via a membrane inlet system. Data collection and analysis are accomplished via a portable PC. The T-CAT is capable of detection limits approaching those of more conventional, nonportable design. The device shows reasonable linearity over wide concentration ranges. Initial results indicate that the T-CAT will be capable of use in a wide range of applications, particularly for environmental monitoring. This article describes the features of the T-CAT, and presents initial results from the membrane inlet/T-CAT system.

  9. Tandem Mass Spectrometry on a Miniaturized Laser Desorption Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Li, Xiang; Cornish, Timothy; Getty, Stephanie A.; Brinckerhoff, William B.

    2016-01-01

    Tandem mass spectrometry (MSMS) is a powerful and widely-used technique for identifying the molecular structure of organic constituents of a complex sample. Application of MSMS to the study of unknown planetary samples on a remote space mission would contribute to our understanding of the origin, evolution, and distribution of extraterrestrial organics in our solar system. Here we report on the realization of MSMS on a miniaturized laser desorption time-of-flight mass spectrometer (LD-TOF-MS), which is one of the most promising instrument types for future planetary missions. This achievement relies on two critical components: a curved-field reflectron and a pulsed-pin ion gate. These enable use of the complementary post-source decay (PSD) and laser-assisted collision induced dissociation (L-CID) MSMS methods on diverse measurement targets with only modest investment in instrument resources such as volume and weight. MSMS spectra of selected molecular targets in various organic standards exhibit excellent agreement when compared with results from a commercial, laboratory-scale TOF instrument, demonstrating the potential of this powerful technique in space and planetary environments.

  10. Plastic scintillation detectors for precision time-of-flight measurements of relativistic heavy ions

    CERN Document Server

    Lin, Wen-Jian; Sun, Bao-Hua; He, Liu-Chun; Lin, Wei-Ping; Liu, Chuan-Ye; Tanihata, Isao; Terashima, Satoru; Tian, Yi; Wang, Feng; Wang, Meng; Zhang, Guang-Xin; Zhang, Xue-Heng; Zhu, Li-Hua; Duan, Li-Min; Hu, Rong-Jiang; Liu, Zhong; Lu, Chen-Gui; Ren, Pei-Pei; Sheng, Li-Na; Sun, Zhi-Yu; Wang, Shi-Tao; Wang, Tao-Feng; Xu, Zhi-Guo; Yan, Duo; Yue, Ke; Zheng, Yong

    2016-01-01

    Plastic scintillation detectors for Time-of-Flight (TOF) measurements are almost essential for event-by-event identification of relativistic rare isotopes. In this work, a pair of plastic scintillation detectors of 50 $\\times$ 50 $\\times$ 3$^{t}$ mm$^3$ and 80 $\\times$ 100 $\\times$ 3$^{t}$ mm$^3$ have been set up at the external target facility (ETF), Institute of Modern Physics. Their time, energy and position responses are measured with $^{18}$O primary beam at 400 MeV/nucleon. After the off-line walk-effect and position corrections, the time resolution of the two detectors are determined to be 27 ps ($\\sigma$) and 36 ps ($\\sigma$), respectively. Both detectors have nearly the same energy resolution of 3$\\%$ ($\\sigma$) and position resolution of 2 mm ($\\sigma$). The detectors have been used successfully in nuclear reaction cross section measurements, and will be be employed for upgrading RIBLL2 beam line at IMP as well as for the high energy branch at HIAF.

  11. Advances in quantitative hepcidin measurements by time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Dorine W Swinkels

    Full Text Available Assays for the detection of the iron regulatory hormone hepcidin in plasma or urine have not yet been widely available, whereas quantitative comparisons between hepcidin levels in these different matrices were thus far even impossible due to technical restrictions. To circumvent these limitations, we here describe several advances in time-of flight mass spectrometry (TOF MS, the most important of which concerned spiking of a synthetic hepcidin analogue as internal standard into serum and urine samples. This serves both as a control for experimental variation, such as recovery and matrix-dependent ionization and ion suppression, and at the same time allows value assignment to the measured hepcidin peak intensities. The assay improvements were clinically evaluated using samples from various patients groups and its relevance was further underscored by the significant correlation of serum hepcidin levels with serum iron indices in healthy individuals. Most importantly, this approach allowed kinetic studies as illustrated by the paired analyses of serum and urine samples, showing that more than 97% of the freely filtered serum hepcidin can be reabsorbed in the kidney. Thus, the here reported advances in TOF MS-based hepcidin measurements represent critical steps in the accurate quantification of hepcidin in various body fluids and pave the way for clinical studies on the kinetic behavior of hepcidin in both healthy and diseased states.

  12. Use of optical fibers in the pulsed time-of-flight laser rangefinding technique

    Science.gov (United States)

    Nissilae, Seppo M.; Kostamovaara, Juha T.; Myllylae, Risto A.

    1990-08-01

    The problems associated with the fibres used in pulsed time-of-flight rangefinders were studied, and particularly errors due to the transit time disturbances of step and graded index fibres as a function of fibre length, input numerical aperture and temperature. The cladding modes and leaky modes ofa fibre can affect the transit time oflight pulses under suitable conditions, so that fibres become sensitive to environmental effects. The effect of temperature is smaller and more linear for acryl-coated fibres than for nylon-coated ones. The main reason for the non-linear effect of temperature on a nylon fibre is the non-linear Young's modulus of nylon as a function of temperature. The increasing transit time of hard clad silica (HCS) fibres at lower temperatures (below +20°C), contrary to glass fibres, can be explained by the different thermal coefficient of the core and cladding, leading to increased non-homogenities on the core-cladding interface.

  13. Characterization studies of Silicon Photomultipliers and crystals matrices for a novel time of flight PET detector

    CERN Document Server

    Auffray, Etiennette; Cortinovis, Daniele; Doroud, Katayoun; Garutti, Erika; Lecoq, Paul; Liu, Zheng; Martinez, Rosana; Paganoni, Marco; Pizzichemi, Marco; Silenzi, Alessandro; Xu, Chen; Zvolský, Milan

    2015-01-01

    This paper describes the characterization of crystal matrices and silicon photomultiplier arrays for a novel Positron Emission Tomography (PET) detector, namely the external plate of the EndoTOFPET-US system. The EndoTOFPET-US collaboration aims to integrate Time-Of-Flight PET with ultrasound endoscopy in a novel multimodal device, capable to support the development of new biomarkers for prostate and pancreatic tumors. The detector consists in two parts: a PET head mounted on an ultrasound probe and an external PET plate. The challenging goal of 1 mm spatial resolution for the PET image requires a detector with small crystal size, and therefore high channel density: 4096 LYSO crystals individually readout by Silicon Photomultipliers (SiPM) make up the external plate. The quality and properties of these components must be assessed before the assembly. The dark count rate, gain, breakdown voltage and correlated noise of the SiPMs are measured, while the LYSO crystals are evaluated in terms of light yield and en...

  14. Monoacylglycerol Analysis Using MS/MSALL Quadruple Time of Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Fei Gao

    2016-08-01

    Full Text Available Monoacylglycerols (MAGs are structural and bioactive metabolites critical for biological function. Development of facile tools for measuring MAG are essential to understand its role in different diseases and various pathways. A data-independent acquisition method, MS/MSALL, using electrospray ionization (ESI coupled quadrupole time of flight mass spectrometry (MS, was utilized for the structural identification and quantitative analysis of individual MAG molecular species. Compared with other acylglycerols, diacylglycerols (DAG and triacylglycerols (TAG, MAG characteristically presented as a dominant protonated ion, [M + H]+, and under low collision energy as fatty acid-like fragments due to the neutral loss of the glycerol head group. At low concentrations (<10 pmol/µL, where lipid-lipid interactions are rare, there was a strong linear correlation between ion abundance and MAG concentration. Moreover, using the MS/MSALL method the major MAG species from human plasma and mouse brown and white adipose tissues were quantified in less than 6 min. Collectively, these results demonstrate that MS/MSALL analysis of MAG is an enabling strategy for the direct identification and quantitative analysis of low level MAG species from biological samples with high throughput and sensitivity.

  15. Depth Errors Analysis and Correction for Time-of-Flight (ToF Cameras

    Directory of Open Access Journals (Sweden)

    Ying He

    2017-01-01

    Full Text Available Time-of-Flight (ToF cameras, a technology which has developed rapidly in recent years, are 3D imaging sensors providing a depth image as well as an amplitude image with a high frame rate. As a ToF camera is limited by the imaging conditions and external environment, its captured data are always subject to certain errors. This paper analyzes the influence of typical external distractions including material, color, distance, lighting, etc. on the depth error of ToF cameras. Our experiments indicated that factors such as lighting, color, material, and distance could cause different influences on the depth error of ToF cameras. However, since the forms of errors are uncertain, it’s difficult to summarize them in a unified law. To further improve the measurement accuracy, this paper proposes an error correction method based on Particle Filter-Support Vector Machine (PF-SVM. Moreover, the experiment results showed that this method can effectively reduce the depth error of ToF cameras to 4.6 mm within its full measurement range (0.5–5 m.

  16. Development of position-sensitive time-of-flight spectrometer for fission fragment research

    CERN Document Server

    Arnold, C W; Meierbachtol, K; Bredeweg, T; Jandel, M; Jorgenson, H J; Laptev, A; Rusev, G; Shields, D W; White, M; Blakeley, R E; Mader, D M; Hecht, A A

    2014-01-01

    A position-sensitive, high-resolution time-of-flight detector for fission fragments has been developed. The SPectrometer for Ion DEterminiation in fission Research (SPIDER) is a $2E-2v$ spectrometer designed to measure the mass of light fission fragments to a single mass unit. The time pick-off detector pairs to be used in SPIDER have been tested with $\\alpha$-particles from $^{229}$Th and its decay chain and $\\alpha$-particles and spontaneous fission fragments from $^{252}$Cf. Each detector module is comprised of a thin electron conversion foil, electrostatic mirror, microchannel plates, and delay-line anodes. Particle trajectories on the order of 700 mm are determined accurately to within 0.7 mm. Flight times on the order of 70 ns were measured with 200 ps resolution FWHM. Computed particle velocities are accurate to within 0.06 mm/ns corresponding to precision of 0.5%. An ionization chamber capable of 400 keV energy resolution coupled with the velocity measurements described here will pave the way for mode...

  17. Exploiting sparsity in time-of-flight range acquisition using a single time-resolved sensor.

    Science.gov (United States)

    Kirmani, Ahmed; Colaço, Andrea; Wong, Franco N C; Goyal, Vivek K

    2011-10-24

    Range acquisition systems such as light detection and ranging (LIDAR) and time-of-flight (TOF) cameras operate by measuring the time difference of arrival between a transmitted pulse and the scene reflection. We introduce the design of a range acquisition system for acquiring depth maps of piecewise-planar scenes with high spatial resolution using a single, omnidirectional, time-resolved photodetector and no scanning components. In our experiment, we reconstructed 64 × 64-pixel depth maps of scenes comprising two to four planar shapes using only 205 spatially-patterned, femtosecond illuminations of the scene. The reconstruction uses parametric signal modeling to recover a set of depths present in the scene. Then, a convex optimization that exploits sparsity of the Laplacian of the depth map of a typical scene determines correspondences between spatial positions and depths. In contrast with 2D laser scanning used in LIDAR systems and low-resolution 2D sensor arrays used in TOF cameras, our experiment demonstrates that it is possible to build a non-scanning range acquisition system with high spatial resolution using only a standard, low-cost photodetector and a spatial light modulator.

  18. Diting: A polarized time-of-flight neutron reflectometer at CMRR reactor in China

    Science.gov (United States)

    Li, Xinxi; Huang, Chaoqiang; Wang, Yan; Chen, Bo; Sun, Guang'ai; Liu, Yaoguang; Gong, Jian; Kang, Wu; Liu, Hangang

    2016-11-01

    A new time-of-flight neutron reflectometer with a polarization option is developed and tested at the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, China. Its scattering geometry is horizontal. The constructed neutron reflectometer is a multipurpose instrument that can be used for the characterization of a stratified microstructure and hidden interfaces of solid thin films. Diting is designed for both magnetic and nonmagnetic multi-layer thin films. Spin polarization and analysis are achieved by transmission magnetized supermirrors. The sample unit is equipped with an electromagnet, which can provide a vertical magnetic field range of 0-1.2 tesla. The available neutron beam is a white beam with wavelength range of 0.15-1.25 nm, which can be cut into different wavelength resolution neutron pulses by a four-disk chopper. A two-dimensional position-sensitive detector is employed to count the specular and off-specular reflected neutron beam. A minimum reflectivity of 10-6 is measured on this instrument.

  19. Gas-phase pesticide measurement using iodide ionization time-of-flight mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. Murschell

    2017-06-01

    Full Text Available Volatilization and subsequent processing in the atmosphere are an important environmental pathway for the transport and chemical fate of pesticides. However, these processes remain a particularly poorly understood component of pesticide lifecycles due to analytical challenges in measuring pesticides in the atmosphere. Most pesticide measurements require long (hours to days sampling times coupled with offline analysis, inhibiting observation of meteorologically driven events or investigation of rapid oxidation chemistry. Here, we present chemical ionization time-of-flight mass spectrometry with iodide reagent ions as a fast and sensitive measurement of four current-use pesticides. These semi-volatile pesticides were calibrated with injections of solutions onto a filter and subsequently volatilized to generate gas-phase analytes. Trifluralin and atrazine are detected as iodide–molecule adducts, while permethrin and metolachlor are detected as adducts between iodide and fragments of the parent analyte molecule. Limits of detection (1 s are 0.37, 0.67, 0.56, and 1.1 µg m−3 for gas-phase trifluralin, metolachlor, atrazine, and permethrin, respectively. The sensitivities of trifluralin and metolachlor depend on relative humidity, changing as much as 70 and 59, respectively, as relative humidity of the sample air varies from 0 to 80 %. This measurement approach is thus appropriate for laboratory experiments and potentially near-source field measurements.

  20. Sensitivity estimation in time-of-flight list-mode positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Herraiz, J. L. [Madrid-MIT M+Visión Consortium, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 and Grupo de Física Nuclear, Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid 28040 (Spain); Sitek, A., E-mail: sarkadiu@gmail.com [Center for Advanced Medical Imaging Sciences, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

    2015-11-15

    Purpose: An accurate quantification of the images in positron emission tomography (PET) requires knowing the actual sensitivity at each voxel, which represents the probability that a positron emitted in that voxel is finally detected as a coincidence of two gamma rays in a pair of detectors in the PET scanner. This sensitivity depends on the characteristics of the acquisition, as it is affected by the attenuation of the annihilation gamma rays in the body, and possible variations of the sensitivity of the scanner detectors. In this work, the authors propose a new approach to handle time-of-flight (TOF) list-mode PET data, which allows performing either or both, a self-attenuation correction, and self-normalization correction based on emission data only. Methods: The authors derive the theory using a fully Bayesian statistical model of complete data. The authors perform an initial evaluation of algorithms derived from that theory and proposed in this work using numerical 2D list-mode simulations with different TOF resolutions and total number of detected coincidences. Effects of randoms and scatter are not simulated. Results: The authors found that proposed algorithms successfully correct for unknown attenuation and scanner normalization for simulated 2D list-mode TOF-PET data. Conclusions: A new method is presented that can be used for corrections for attenuation and normalization (sensitivity) using TOF list-mode data.

  1. Facile time-of-flight methods for characterizing pulsed superfluid helium droplet beams.

    Science.gov (United States)

    He, Yunteng; Zhang, Jie; Li, Yang; Freund, William M; Kong, Wei

    2015-08-01

    We present two facile time-of-flight (TOF) methods of detecting superfluid helium droplets and droplets with neutral dopants. Without an electron gun and with only a heated filament and pulsed electrodes, the electron impact ionization TOF mass spectrometer can resolve ionized helium clusters such as He2(+) and He4(+), which are signatures of superfluid helium droplets. Without ionizing any helium atoms, multiphoton non-resonant laser ionization of CCl4 doped in superfluid helium droplets at 266 nm generates complex cluster ions of dopant fragments with helium atoms, including (He)(n)C(+), (He)(n)Cl(+), and (He)(n)CCl(+). Using both methods, we have characterized our cryogenic pulsed valve—the Even-Lavie valve. We have observed a primary pulse with larger helium droplets traveling at a slower speed and a rebound pulse with smaller droplets at a faster speed. In addition, the pickup efficiency of dopant is higher for the primary pulse when the nozzle temperature is higher than 13 K, and the total time duration of the doped droplet pulse is only on the order of 20 μs. These results stress the importance of fast and easy characterization of the droplet beam for sensitive measurements such as electron diffraction of doped droplets.

  2. Strong overtones and combination bands in ultraviolet resonance Raman spectroscopy.

    Science.gov (United States)

    Efremov, Evtim V; Ariese, Freek; Mank, Arjan J G; Gooijer, Cees

    2006-05-01

    Ultraviolet resonance Raman spectroscopy is carried out using a continuous wave frequency-doubled argon ion laser operated at 229, 244, and 257 nm in order to characterize the overtones and combination bands for several classes of organic compounds in liquid solutions. Contrary to what is generally anticipated, for molecules such as pyrene and anthracene, strong overtones and combination bands can show up; it is demonstrated that their intensity depends critically on the applied laser wavelength. If the excitation wavelength corresponds with a purely electronic transition--this applies to a good approximation for 244-nm excitation in the case of pyrene and for 257-nm excitation in the case of anthracene--mostly fundamental vibrations (up to 1700 cm(-1)) are observed. Overtones and combination bands are detected but are rather weak. However, if the laser overlaps with the vibronic region--as holds for 229- and 257-nm excitation for pyrene and 244-nm excitation for anthracene--very strong bands are found in the region 1700-3400 cm(-1). As illustrated for pyrene at 257 nm, all these bands can be assigned to first overtones or binary combinations of fundamental vibrations. Their intensity distribution can roughly be simulated by multiplying the relative intensities of the fundamental bands. Significant bands can also be found in the region 3400-5000 cm(-1), corresponding with second overtones and ternary combinations. It is shown that these findings are not restricted to planar and rigid molecules with high symmetry. Substituted pyrenes exhibit similar effects, and relatively strong overtones are also observed for adenosine monophosphate and for abietic acid. The reasons for these observations are discussed, as well as the potential applicability for analytical purposes.

  3. An iodide-adduct high-resolution time-of-flight chemical-ionization mass spectrometer: application to atmospheric inorganic and organic compounds.

    Science.gov (United States)

    Lee, Ben H; Lopez-Hilfiker, Felipe D; Mohr, Claudia; Kurtén, Theo; Worsnop, Douglas R; Thornton, Joel A

    2014-06-03

    A high-resolution time-of-flight chemical-ionization mass spectrometer (HR-ToF-CIMS) using Iodide-adducts has been characterized and deployed in several laboratory and field studies to measure a suite of organic and inorganic atmospheric species. The large negative mass defect of Iodide, combined with soft ionization and the high mass-accuracy (5500) of the time-of-flight mass spectrometer, provides an additional degree of separation and allows for the determination of elemental compositions for the vast majority of detected ions. Laboratory characterization reveals Iodide-adduct ionization generally exhibits increasing sensitivity toward more polar or acidic volatile organic compounds. Simultaneous retrieval of a wide range of mass-to-charge ratios (m/Q from 25 to 625 Th) at a high frequency (>1 Hz) provides a comprehensive view of atmospheric oxidative chemistry, particularly when sampling rapidly evolving plumes from fast moving platforms like an aircraft. We present the sampling protocol, detection limits and observations from the first aircraft deployment for an instrument of this type, which took place aboard the NOAA WP-3D aircraft during the Southeast Nexus (SENEX) 2013 field campaign.

  4. Detection of an extended human volatome with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Michael Phillips

    Full Text Available BACKGROUND: Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOF MS has been proposed as a powerful new tool for multidimensional analysis of complex chemical mixtures. We investigated GCxGC-TOF MS as a new method for identifying volatile organic compounds (VOCs in normal human breath. METHODS: Samples of alveolar breath VOCs and ambient room air VOC were collected with a breath collection apparatus (BCA onto separate sorbent traps from 34 normal healthy volunteers (mean age = 40 yr, SD = 17 yr, male/female = 19/15. VOCs were separated on two serial capillary columns separated by a cryogenic modulator, and detected with TOF MS. The first and second dimension columns were non-polar and polar respectively. RESULTS: BCA collection combined with GC×GC-TOF MS analysis identified approximately 2000 different VOCs in samples of human breath, many of which have not been previously reported. The 50 VOCs with the highest alveolar gradients (abundance in breath minus abundance in ambient room air mostly comprised benzene derivatives, acetone, methylated derivatives of alkanes, and isoprene. CONCLUSIONS: Collection and analysis of breath VOCs with the BCA-GC×GC-TOF MS system extended the size of the detectable human volatile metabolome, the volatome, by an order of magnitude compared to previous reports employing one-dimensional GC-MS. The size of the human volatome has been under-estimated in the past due to coelution of VOCs in one-dimensional GC analytical systems.

  5. Uptake of Ra during the recrystallization of barite: a microscopic and time of flight-secondary ion mass spectrometry study.

    Science.gov (United States)

    Klinkenberg, Martina; Brandt, Felix; Breuer, Uwe; Bosbach, Dirk

    2014-06-17

    A combined macroscopic and microanalytical approach was applied on two distinct barite samples from Ra uptake batch experiments using time of flight-secondary ion mass spectrometry (ToF-SIMS) and detailed scanning electron microscopy (SEM) investigations. The experiments were set up at near to equilibrium conditions to distinguish between two possible scenarios for the uptake of Ra by already existent barite: (1) formation of a Ba1-xRaxSO4 solid solution surface layer on the barite or (2) a complete recrystallization, leading to homogeneous Ba1-xRaxSO4 crystals. It could be clearly shown that Ra uptake in all barite particles analyzed within this study is not limited to the surface but extends to the entire solid. For most grains a homogeneous distribution of Ra could be determined, indicating a complete recrystallization of barite into a Ba1-xRaxSO4 solid solution. The maxima of the Ra/Ba intensity ratio distribution histograms calculated from ToF-SIMS are identical with the expected Ra/Ba ratios calculated from mass balance assuming a complete recrystallization. In addition, the role of Ra during the recrystallization of barite was examined via detailed SEM investigations. Depending on the type of barite used, an additional coarsening effect or a strong formation of oriented aggregates was observed compared to blank samples without Ra. In conclusion, the addition of Ra to a barite at close to equilibrium conditions has a major impact on the system leading to a fast re-equilibration of the solid to a Ba1-xRaxSO4 solid solution and visible effects on the particle size distribution, even at room temperature.

  6. Identification of beer-spoilage bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Wieme, Anneleen D; Spitaels, Freek; Aerts, Maarten; De Bruyne, Katrien; Van Landschoot, Anita; Vandamme, Peter

    2014-08-18

    Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-spoilage bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid bacteria (AAB) and lactic acid bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-spoilage bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of spoilage bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Multicapillary gas chromatography coupled to inductively coupled plasma-time-of-flight mass spectrometry for rapid mercury speciation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jitaru, Petru; Goenaga Infante, Heidi; Adams, Freddy C

    2003-08-11

    A simple, rapid and accurate method on the basis of multicapillary gas chromatography (MCGC) combined with inductively coupled plasma-time-of-flight mass spectrometry (ICP-TOFMS) was developed for speciation analysis of methylmercury (MeHg{sup +}) and inorganic mercury (Hg{sup 2+}). The potential of the ICP-TOFMS for transient multi-isotope detection of very short signals (peak width of 0.4 s at half peak height) was evaluated. Two injection systems (purge-and-trap (PTI) and split (SI) injections) were compared in terms of species separation resolution and transient signal profile. Using purge-and-trap injection, after in situ derivatization of the ionic mercury species with sodium tetraethylborate, a baseline separation of MeHg{sup +} and Hg{sup 2+} was achieved within a chromatographic run of <35 s. To correct for matrix-induced ion signal variation and instrumental drift, propylmercury (PrHg{sup +}) was used as internal standard. Detection limits of 16 and 257 fg g{sup -1} for MeHg{sup +} (as Hg) and Hg{sup 2+}, respectively, were achieved. The analytical precision (R.S.D. (%)) for 10 successive injections of a standard mixture containing 10 pg MeHg{sup +} (as Hg) and Hg{sup 2+} was 1.2% for MeHg{sup +} and 4.1% for Hg{sup 2+}. The method was validated by analysis of two biological certified reference materials (CRM): a dogfish muscle (DORM-2) and a freeze-dried tuna fish (CRM 464)

  8. Characterization and quantitative analysis of surfactants in textile wastewater by liquid chromatography/quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    González, Susana; Petrović, Mira; Radetic, Maja; Jovancic, Petar; Ilic, Vesna; Barceló, Damià

    2008-05-01

    A method based on the application of ultra-performance liquid chromatography (UPLC) coupled to hybrid quadrupole-time-of-flight mass spectrometry (QqTOF-MS) with an electrospray (ESI) interface has been developed for the screening and confirmation of several anionic and non-ionic surfactants: linear alkylbenzenesulfonates (LAS), alkylsulfate (AS), alkylethersulfate (AES), dihexyl sulfosuccinate (DHSS), alcohol ethoxylates (AEOs), coconut diethanolamide (CDEA), nonylphenol ethoxylates (NPEOs), and their degradation products (nonylphenol carboxylate (NPEC), octylphenol carboxylate (OPEC), 4-nonylphenol (NP), 4-octylphenol (OP) and NPEO sulfate (NPEO-SO4). The developed methodology permits reliable quantification combined with a high accuracy confirmation based on the accurate mass of the (de)protonated molecules in the TOFMS mode. For further confirmation of the identity of the detected compounds the QqTOF mode was used. Accurate masses of product ions obtained by performing collision-induced dissociation (CID) of the (de)protonated molecules of parent compounds were matched with the ions obtained for a standard solution. The method was applied for the quantitative analysis and high accuracy confirmation of surfactants in complex mixtures in effluents from the textile industry. Positive identification of the target compounds was based on accurate mass measurement of the base peak, at least one product ion and the LC retention time of the analyte compared with that of a standard. The most frequently surfactants found in these textile effluents were NPEO and NPEO-SO4 in concentrations ranging from 0.93 to 5.68 mg/L for NPEO and 0.06 to 4.30 mg/L for NPEO-SO4. AEOs were also identified.

  9. Rapid identification of polymer additives by atmospheric solid analysis probe with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Du, Zhenxia; Zhang, Yun; Li, Ailin; Lv, Surong

    2014-10-15

    A method using an atmospheric solid analysis probe (ASAP) combined with quadrupole time-of-flight mass spectrometry (QTOFMS) assisted by a pre-built MS library was found to be efficient in fast and direct analysis of additives for polymers. By this method, sample pretreatment could be eliminated from the additives identification process. Some crucial parameters, such as desolvation gas temperature, corona current, sample cone voltage and collision energy, should be optimized. A MS library of 100 polymer additives, including phenols (Irganox 1010, Irganox 1076), hydroxyl phenyl benzotriazole derivatives (Tinuvin 326, Tinuvin 327, Tinuvin 328), hindered amines (Tinuvin 944, Tinuvin 770) and plasticizers, was built based on the optimized conditions. To verify the application of the MS library, the ASAP-QTOFMS method was applied to identify complex additives, a simulated polypropylene (PP) sample and a real polymethylmethacrylate (PMMA) sample purchased from a local market. By searching the exact mass, and comparing the MS and MS/MS spectra of samples with standards in the MS library, complex additives such as Irganox GX 2921, as well as additives in PP and PMMA samples, could be identified quickly and easily. The determination of mass accuracy increased the confidence of peak identification as well. Moreover, the results also provided information of the characterization for PP and PMMA polymers. A rapid identification method has been developed for polymer additives by ASAP-QTOFMS. A MS library of 100 polymer additives was built by this method. Using ASAP-QTOFMS assisted by the pre-built MS library, polymer additives can be quickly identified. This method was found to be a promising tool in the rapid analysis of additives in polymers and polymer matrices. Copyright © 2014 John Wiley & Sons, Ltd.

  10. Zoom-TOFMS: addition of a constant-momentum-acceleration "zoom" mode to time-of-flight mass spectrometry.

    Science.gov (United States)

    Dennis, Elise A; Gundlach-Graham, Alexander W; Ray, Steven J; Enke, Christie G; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

    2014-11-01

    In this study, we demonstrate the performance of a new mass spectrometry concept called zoom time-of-flight mass spectrometry (zoom-TOFMS). In our zoom-TOFMS instrument, we combine two complementary types of TOFMS: conventional, constant-energy acceleration (CEA) TOFMS and constant-momentum acceleration (CMA) TOFMS to provide complete mass-spectral coverage as well as enhanced resolution and duty factor for a narrow, targeted mass region, respectively. Alternation between CEA- and CMA-TOFMS requires only that electrostatic instrument settings (i.e., reflectron and ion optics) and ion acceleration conditions be changed. The prototype zoom-TOFMS instrument has orthogonal-acceleration geometry, a total field-free distance of 43 cm, and a direct-current glow-discharge ionization source. Experimental results demonstrate that the CMA-TOFMS "zoom" mode offers resolution enhancement of 1.6 times over single-stage acceleration CEA-TOFMS. For the atomic mass range studied here, the maximum resolving power at full-width half-maximum observed for CEA-TOFMS was 1,610 and for CMA-TOFMS the maximum was 2,550. No difference in signal-to-noise (S/N) ratio was observed between the operating modes of zoom-TOFMS when both were operated at equivalent repetition rates. For a 10-kHz repetition rate, S/N values for CEA-TOFMS varied from 45 to 990 and from 67 to 10,000 for CMA-TOFMS. This resolution improvement is the result of a linear TOF-to-mass scale and the energy-focusing capability of CMA-TOFMS. Use of CMA also allows ions outside a given m/z range to be rejected by simple ion-energy barriers to provide a substantial improvement in duty factor.

  11. Results of the ALICE time-of-flight detector from the 2009 cosmic-ray data taking

    Energy Technology Data Exchange (ETDEWEB)

    Akindinov, A.; Kiselev, S.; Malkevich, D.; Nedosekin, A.; Ryabinin, M.; Voloshin, K. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Alici, A.; Preghenella, R. [Sezione INFN, Bologna (Italy); Museo Storico della Fisica e Centro Studi e Ricerche ' ' Enrico Fermi' ' , Roma (Italy); Antonioli, P.; Cara Romeo, G.; Cindolo, F.; Hatzifotiadou, D.; Laurenti, G.; Margotti, A.; Nania, R.; Pesci, A.; Pinazza, O.; Scapparone, E.; Williams, M.C.S. [Sezione INFN, Bologna (Italy); Arcelli, S.; Basile, M.; Bellini, F.; Cifarelli, L.; Guerzoni, B.; Scioli, G.; Silenzi, A. [Dipartimento di Fisica dell' Universita, Bologna (Italy); Sezione INFN, Bologna (Italy); Caffarri, D. [Dipartimento di Fisica dell' Universita, Bologna (Italy); Sezione INFN, Bologna (Italy); INFN, Padova (Italy); University of Padova, Padova (Italy); De Caro, A.; De Gruttola, D.; De Pasquale, S.; Fusco Girard, M.; Pagano, P. [Dipartimento di Fisica dell' Universita Salerno (Italy); INFN, Salerno (Italy); Doroud, K.; Seo, J. [World Laboratory, Geneva (Switzerland); Jung, W.W.; Kim, D.W.; Kim, J.S.; Lee, K.; Lee, S.C. [Gangneung-Wonju National University, Department of Physics, Gangneung (Korea); Noferini, F. [Sezione INFN, Bologna (Italy); INFN-CNAF, Bologna (Italy); Zampolli, C. [INFN-CNAF, Bologna (Italy); CERN, Geneva (Switzerland)

    2010-08-15

    The Time-Of-Flight detector (TOF) of the ALICE experiment at the CERN LHC is based on Multi-gap Resistive Plate Chambers (MRPCs). The TOF detector consists of 152928 readout channels covering a total area of 141 m{sup 2}. In this paper the results of the calibration with cosmic-ray data collected during 2009 are presented. (orig.)

  12. Performance of matrix-assisted laser desorption-time of flight mass spectrometry for identification of clinical yeast isolates

    DEFF Research Database (Denmark)

    Rosenvinge, Flemming S; Dzajic, Esad; Knudsen, Elisa;

    2013-01-01

    Accurate and fast yeast identification is important when treating patients with invasive fungal disease as susceptibility to antifungal agents is highly species related. Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS) provides a powerful tool with a clear potential...

  13. Application of matrix-assisted laser desorption/ionization to on-line aerosol time-of-flight mass spectrometry

    NARCIS (Netherlands)

    Stowers, M.A.; Wuijckhuijse, A.L. van; Marijnissen, J.C.M.; Scarlett, B.; Baar, B.L.M. van; Kientz, Ch.E.

    2000-01-01

    Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of- flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated wi

  14. Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

    DEFF Research Database (Denmark)

    Bache, Nicolai; Rand, Kasper Dyrberg; Roepstorff, Peter;

    2008-01-01

    have now measured the level of hydrogen scrambling in a deprotonated, selectively labeled peptide using MALDI tandem time-of-flight mass spectrometry. Our results conclusively show that hydrogen scrambling is prevalent in the deprotonated peptide upon collisional activation. The amide hydrogens ((1)H...

  15. Highly sensitive on-site detection of drugs adulterated in botanical dietary supplements using thin layer chromatography combined with dynamic surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Fang, Fang; Qi, Yunpeng; Lu, Feng; Yang, Liangbao

    2016-01-01

    The phenomenon of botanical dietary supplements (BDS) doped with illegal adulterants has become a serious problem all over the world, which could cause great threat to human's health. Therefore, it is of great value to identify BDS. Herein, we put forward a highly sensitive method for on-site detection of antitussive and antiasthmatic drugs adulterated in BDS using thin layer chromatography (TLC) combined with dynamic surface enhanced Raman spectroscopy (DSERS). Adulterants in BDS were separated on a TLC plate and located under UV illumination. Then DSERS detection was performed using a portable Raman spectrometer with 50% glycerol silver colloid serving as DSERS active substrate. Here, the effects of different solvents on detection efficacy were evaluated using phenformin hydrochloride (PHE) as a probe. It was shown that 50% glycerol resulted in higher SERS enhancement and relatively higher stability. Moreover, practical application of this novel TLC-DSERS method was demonstrated with rapid analysis of real BDS samples and one sample adulterated with benproperine phosphate (BEN) was found. Furthermore, the obtained result was verified by ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF/MS). The sensitivity of the TLC-DSERS technique is 1-2 orders of magnitude higher than that of TLC-SERS technique. The results turned out that this combined method would have good prospects for on-site and sensitive detection of adulterated BDS. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. An FPGA Wave Union TDC for Time-of-Flight Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; /Fermilab

    2009-01-01

    An 18-channel time-of-flight (TOF) grade time-to-digit converter (TDC) has been implemented in a low cost FPGA device. The TDC has the following unique features. (1) The time recording structures of the TDC is based on the 'wave union TDC' we developed in our previous work. A leading edge of the input hit launches a bit pattern, or wave union into the delay chain-register array structure which yields two usable measurements. The two measurements effectively sub-divide timing bins for each other especially the 'ultra-wide bins' caused by the FPGA logic array block (LAB) structure and improves measurement precision both in terms of maximum bin width and RMS resolution. A coarser measurement on input signal trailing edge is also provided for time-over-threshold (TOT) applications. (2) The TDC supports advanced timing reference distribution schemes that are superior to conventional common start/stop schemes. The TDC has 16 regular measurement channels plus two channels for timing reference. The timing reference is established with multiple measurements rather than single shot common start/stop. An advanced scheme, the mean-timing approach even eliminates needs of high quality timing distribution media. (3) The ASIC-like encapsulation of the FPGA TDC significantly shorten the learning curve for potential users while maintain certain flexibility for various applications. Necessary digital post-processing functions including semicontinuous automatic calibration, data buffer, data link jam prevention logic etc. are integrated into the firmware to provide a turn-key solution for users.

  17. Time-of-flight secondary neutral & ion mass spectrometry using swift heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Breuer, L.; Meinerzhagen, F. [Universität Duisburg-Essen, Fakultät für Physik, D-47048 Duisburg (Germany); Bender, M.; Severin, D. [Gesellschaft für Schwerionenforschung GSI, D-64291 Darmstadt (Germany); Wucher, A., E-mail: andreas.wucher@uni-due.de [Universität Duisburg-Essen, Fakultät für Physik, D-47048 Duisburg (Germany)

    2015-12-15

    We report on a new time-of-flight (TOF) spectrometer designed to investigate sputtering phenomena induced by swift heavy ions in the electronic stopping regime. In this experiment, particular emphasis is put on the detection of secondary ions along with their emitted neutral counterparts in order to examine the ionization efficiency of the sputtered material. For the detection of neutral species, the system is equipped with a pulsed VUV laser for post-ionization of sputtered neutral atoms and molecules via single photon ionization at a wavelength of 157 nm (corresponding to 7.9 eV photon energy). For alignment purposes and in order to facilitate comparison to nuclear sputtering conditions, the system also includes a 5 keV Ar{sup +} ion beam directed to the same sample area. The instrument has been added to the M1-branch beam line at the German accelerator facility in Darmstadt (GSI) and was tested with 4.8 MeV/u Au{sup 26+} ions impinging onto various samples including metals, salts and organic films. It is found that secondary ion and neutral spectra obtained under both bombardment conditions can be acquired in an interleaved manner throughout a single accelerator pulse cycle, thus making efficient use of valuable beam time. In addition, the keV ion beam can be intermittently switched to dc mode between subsequent data acquisition windows and accelerator pulses in order to ensure reproducible surface conditions. For the case of a dynamically sputter cleaned metal surface, comparison of secondary ion and neutral signals obtained under otherwise identical instrumental conditions reveals a nearly identical ionization probability of atoms emitted under electronic and nuclear sputtering conditions.

  18. Determination of glycated and acetylated hemoglobins in cord blood by time-of-flight mass spectrometry.

    Science.gov (United States)

    Dupont, Félix O; Gagnon, René; Ardilouze, Jean-Luc; Auray-Blais, Christiane

    2011-07-01

    The characterization of cord blood hemoglobin at the molecular level is a daunting challenge because hemoglobin F (HbF) and hemoglobin A (HbA) coexist in neonatal blood. We developed and validated a method using electrospray time-of-flight mass spectrometry (ES-TOF-MS) that measures, in a single analysis, relative levels of glycated and acetylated hemoglobin and allows the calculation of relative proportions of HbA, HbF(0), and HbF(1) in cord blood. Specific sections of acquired spectra were deconvoluted using a maximum entropy-based approach to true mass scale spectra. Mass precisions were less than 3 ppm with similar accuracies. Intra-interday precisions for α- and γ-chain glycation levels were 2.10%/3.72% and 2.75%/6.79%, respectively. The linearity of the α-chain glycation response was excellent (r(2) = 0.9990). We performed sample analysis on 39 cord blood specimens and found that the glycated α- and γ-chain levels were 2.27 ± 0.21% and 2.38 ± 0.29%, respectively, while the acetylated (G)γ and (A)γ-chain levels were 8.48 ± 0.53% and 7.14 ± 0.74%, respectively. We observed three types of HbF distinguishable by the intensities of γ-chain variants. Two-thirds of cord blood specimens were classified as HbF(I) with an intensity ratio (G)γ/(A)γ of 1.90 ± 0.12. For HbF(II) type (10/39 neonates), the intensity ratio of (G)γ/(A)γ was 3.71 ± 0.28. For three neonates with HbF(III), no (A)γ-chain was detected.

  19. Mass spectra and time-of-flight distributions of helium cluster beams

    Energy Technology Data Exchange (ETDEWEB)

    Buchenau, H.; Knuth, E.L.; Northby, J.; Toennies, J.P.; Winkler, C. (Max-Planck-Institut fuer Stroemungsforschung, Bunsenstrasse 10, D-3400 Goettingen, Federal Republic of Germany (DE))

    1990-06-01

    Liquid helium clusters are produced by expanding gaseous {sup 4} He into a vacuum from a cold source with temperatures between 5 and 20 K at stagnation pressures from {ital P}{sub 0} =8 to 20 bar and are studied by time-of-flight (TOF) and mass spectrometry. At low temperatures, {ital T}{sub 0} {lt}12 K, the mass spectra show several anomalies which can be attributed to pick-up of residual gases. At {ital T}{sub 0} {lt}10K, there is evidence for a very intense peak at {ital m}=16 amu which is attributed to He{sup +}{sub 4} . Depending on the temperatures, the TOF spectra reveal ions with three different velocities. These TOF observations are analyzed using isentropic lines in the known phase diagram of {sup 4} He, which take into account deviations from ideal gas behavior. Three qualitatively different expansion regimes are identified: (I) the expansion proceeds through a region on the high temperature side of the critical point, (II) the expansion passes through or near the critical point, and (III) the expansion passes through a region on the low temperature side of the critical point. The mass spectra, peak velocities and speed ratios, when analyzed with the aid of the phase diagram, indicate that (a) two of the TOF peaks are due to clusters, (b) the fastest cluster peak is due to clusters formed by condensation of gas phase atoms, and (c) the slowest cluster peak is due to either separation into two phases (regime II) or disintegration of a liquid phase (regime III). Measured conversions of initial enthalpy into free jet kinetic energy suggest that the cluster temperature undergoes a sharp drop to a very low temperature approaching 0 K at {ital T}{sub 0} {lt}6.5 K where the expansion isentrope intersects the liquid--vapor line upstream from the source orifice.

  20. Investigation of isovaline enantiomeric excesses in CM meteorites using liquid chromatography time of flight mass spectrometry

    Science.gov (United States)

    Glavin, Daniel P.; Dworkin, Jason P.

    2003-01-01

    The enantiomeric abundances of the alpha-dialkyl amino acid isovaline were measured in the CM2 meteorites Murchison and LEW 90500 using a new liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS) technique coupled with OPA/NAC derivatization and UV fluorescence detection. Previous analyses of Murchison have shown that L-enantiomeric excesses of isovaline range from 0 to 15.2% with significant variation between meteorite fragments [1]. For this study, hot water extracts of interior fragments (> 2 cm from fusion crust) of the Murchison (USNM 6650.2, mass 6 g) and LEW 90500 (split 69, parent 1, mass 5 g) carbonaceous meteorites were analyzed. Enantiomeric excesses were measured using the single ion LC-ToF-MS trace for the OPA/NAC derivative of isovaline at d z 393.15 (Fig. 1). L-isovaline excesses in these meteorite samples ranged from 18.9 to 20.5% for Murchison and -0.5 to 3.0% for LEW 90500. The measured values for Murchison are the largest enantiomeric excesses for isovaline reported to date. The enantiomeric excesses of L-isovaline cannot be the result of interference from other C5 amino acid isomers present in the meteorites or terrestrial contamination from the landing site environments. The L-isovaline excesses in Murchison are inconsistent with the synthesis of all of the isovaline by the Strecker-cyanohydrin pathway on the CM meteorite parent body. The mechanism(s) for the formation of the enantiomeric asymmetry in isovaline in Murchison are currently unknown and it is not clear how the asymmetry of alpha-dialkyl amino acids could be transferred to the a-hydrogen protein amino acids common in all life on Earth today.

  1. Development of analytically capable time-of-flight mass spectrometer with continuous ion introduction

    Science.gov (United States)

    Hárs, György; Dobos, Gábor

    2010-03-01

    The present article describes the results and findings explored in the course of the development of the analytically capable prototype of continuous time-of-flight (CTOF) mass spectrometer. Currently marketed pulsed TOF (PTOF) instruments use ion introduction with a 10 ns or so pulse width, followed by a waiting period roughly 100 μs. Accordingly, the sample is under excitation in 10-4 part of the total measuring time. This very low duty cycle severely limits the sensitivity of the PTOF method. A possible approach to deal with this problem is to use linear sinusoidal dual modulation technique (CTOF) as described in this article. This way the sensitivity of the method is increased, due to the 50% duty cycle of the excitation. All other types of TOF spectrometer use secondary electron multiplier (SEM) for detection, which unfortunately discriminates in amplification in favor of the lighter ions. This discrimination effect is especially undesirable in a mass spectrometric method, which targets high mass range. In CTOF method, SEM is replaced with Faraday cup detector, thus eliminating the mass discrimination effect. Omitting SEM is made possible by the high ion intensity and the very slow ion detection with some hundred hertz detection bandwidth. The electrometer electronics of the Faraday cup detector operates with amplification 1010 V/A. The primary ion beam is highly monoenergetic due to the construction of the ion gun, which made possible to omit any electrostatic mirror configuration for bunching the ions. The measurement is controlled by a personal computer and the intelligent signal generator Type Tabor WW 2571, which uses the direct digital synthesis technique for making arbitrary wave forms. The data are collected by a Labjack interface board, and the fast Fourier transformation is performed by the software. Noble gas mixture has been used to test the analytical capabilities of the prototype setup. Measurement presented proves the results of the mathematical

  2. Development of analytically capable time-of-flight mass spectrometer with continuous ion introduction.

    Science.gov (United States)

    Hárs, György; Dobos, Gábor

    2010-03-01

    The present article describes the results and findings explored in the course of the development of the analytically capable prototype of continuous time-of-flight (CTOF) mass spectrometer. Currently marketed pulsed TOF (PTOF) instruments use ion introduction with a 10 ns or so pulse width, followed by a waiting period roughly 100 micros. Accordingly, the sample is under excitation in 10(-4) part of the total measuring time. This very low duty cycle severely limits the sensitivity of the PTOF method. A possible approach to deal with this problem is to use linear sinusoidal dual modulation technique (CTOF) as described in this article. This way the sensitivity of the method is increased, due to the 50% duty cycle of the excitation. All other types of TOF spectrometer use secondary electron multiplier (SEM) for detection, which unfortunately discriminates in amplification in favor of the lighter ions. This discrimination effect is especially undesirable in a mass spectrometric method, which targets high mass range. In CTOF method, SEM is replaced with Faraday cup detector, thus eliminating the mass discrimination effect. Omitting SEM is made possible by the high ion intensity and the very slow ion detection with some hundred hertz detection bandwidth. The electrometer electronics of the Faraday cup detector operates with amplification 10(10) V/A. The primary ion beam is highly monoenergetic due to the construction of the ion gun, which made possible to omit any electrostatic mirror configuration for bunching the ions. The measurement is controlled by a personal computer and the intelligent signal generator Type Tabor WW 2571, which uses the direct digital synthesis technique for making arbitrary wave forms. The data are collected by a Labjack interface board, and the fast Fourier transformation is performed by the software. Noble gas mixture has been used to test the analytical capabilities of the prototype setup. Measurement presented proves the results of the

  3. Implementation of Ion/Ion Reactions in a Quadrupole/Time-of-Flight Tandem Mass Spectrometer

    Science.gov (United States)

    Xia, Yu; Chrisman, Paul A.; Erickson, David E.; Liu, Jian; Liang, Xiaorong; Londry, Frank A.; Yang, Min J.; McLuckey, Scott A.

    2008-01-01

    A commercial quadrupole/time-of-flight (QqTOF) tandem mass spectrometer has been adapted for ion/ion reaction studies. To enable mutual storage of oppositely charged ions in a linear ion trap, the oscillating quadrupole field of the second quadrupole of the system (Q2) serves to store ions in the radial dimension while auxiliary RF is superposed on the end lenses of Q2 during the reaction period to create barriers in the axial dimension. A pulsed dual electrospray (ESI) source is directly coupled to the instrument interface for the purpose of proton transfer reactions. Singly and doubly charged protein ions as high in mass as 66 kDa are readily formed and observed after proton transfer reactions. For the modified instrument, the mass resolving power is about 8000 for a wide m/z range and the mass accuracy is ~20 ppm for external calibration and ~5 ppm for internal calibration after ion/ion reactions. Parallel ion parking is demonstrated with a six-component protein mixture, which shows the potential application of reducing spectral complexity and concentrating certain charge states. The current system has high flexibility with respect to defining MSn experiments involving collision-induced dissociation (CID) and ion/ion reactions. Protein precursor and CID product masses can be determined with good accuracy, providing an attractive platform for top-down proteomics. Electron transfer dissociation (ETD) ion/ion reactions are implemented by using a pulsed nano-ESI/atmospheric pressure chemical ionization (APCI) dual source for ionization. The reaction between protonated peptide ions and radical anions of 1,3-dinitrobenzene formed exclusively c- and z- type fragment ions. PMID:16771545

  4. Time-of-flight camera technique for augmented reality in computer-assisted interventions

    Science.gov (United States)

    Mersmann, Sven; Müller, Michael; Seitel, Alexander; Arnegger, Florian; Tetzlaff, Ralf; Dinkel, Julien; Baumhauer, Matthias; Schmied, Bruno; Meinzer, Hans-Peter; Maier-Hein, Lena

    2011-03-01

    Augmented reality (AR) for enhancement of intra-operative images is gaining increasing interest in the field of navigated medical interventions. In this context, various imaging modalities such as ultrasound (US), C-Arm computed tomography (CT) and endoscopic images have been applied to acquire intra-operative information about the patient's anatomy. The aim of this paper was to evaluate the potential of the novel Time-of-Flight (ToF) camera technique as means for markerless intra-operative registration. For this purpose, ToF range data and corresponding CT images were acquired from a set of explanted non-transplantable human and porcine organs equipped with a set of marker that served as targets. Based on a rigid matching of the surfaces generated from the ToF images with the organ surfaces generated from the CT data, the targets extracted from the planning images were superimposed on the 2D ToF intensity images, and the target visualization error (TVE) was computed as quality measure. Color video data of the same organs were further used to assess the TVE of a previously proposed marker-based registration method. The ToF-based registration showed promising accuracy yielding a mean TVE of 2.5+/-1.1 mm compared to 0.7+/-0.4 mm with the marker-based approach. Furthermore, the target registration error (TRE) was assessed to determine the anisotropy in the localization error of ToF image data. The TRE was 8.9+/- 4.7 mm on average indicating a high localization error in the viewing direction of the camera. Nevertheless, the young ToF technique may become a valuable means for intra-operative surface acquisition. Future work should focus on the calibration of systematic distance errors.

  5. A high-resolution time-of-flight spectrometer for fission fragments and ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosev, Krasimir Milchev

    2007-07-01

    For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ({sup 226}Ra,{sup 222}Rn,{sup 210}Po,{sup 218}Po,{sup 214}Po) {alpha}-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a {sup 238}U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

  6. In-home hierarchical posture classification with a time-of-flight 3D sensor.

    Science.gov (United States)

    Diraco, Giovanni; Leone, Alessandro; Siciliano, Pietro

    2014-01-01

    A non-invasive technique for posture classification suitable to be used in several in-home scenarios is proposed and preliminary validation results are presented. 3D point cloud sequences were acquired using a single time-of-flight sensor working in a privacy preserving modality and they were processed with a low power embedded PC. In order to satisfy different application requirements (e.g. covered distance range, processing speed and discrimination capabilities), a twofold discrimination approach was investigated in which features were hierarchically arranged from coarse to fine by exploiting both topological and volumetric representations. The topological representation encoded the intrinsic topology of the body's shape using a skeleton-based structure, thus guaranteeing invariance to scale, rotations and postural changes and achieving a high level of detail with a moderate computational cost. On the other hand, using the volumetric representation features were described in terms of 3D cylindrical histograms working within a wider range of distances in a faster way and also guaranteeing good invariance properties. The discrimination capabilities were evaluated in four different real-home scenarios related with the fields of ambient assisted living and homecare, namely "dangerous event detection", "anomalous behaviour detection", "activities recognition" and "natural human-ambient interaction". For each mentioned scenario, the discrimination capabilities were evaluated in terms of invariance to viewpoint changes, representation capabilities and classification performance, achieving promising results. The two feature representation approaches exhibited complementary characteristics showing high reliability with classification rates greater than 97%. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Multi-Wavelength Laser Transmitter for the Two-Step Laser Time-of-Flight Mass Spectrometer

    Science.gov (United States)

    Yu, Anthony W.; Li, Steven X.; Fahey, Molly E.; Grubisic, Andrej; Farcy, Benjamin J.; Uckert, Kyle; Li, Xiang; Getty, Stephanie

    2017-01-01

    Missions to diverse Outer Solar System bodies will require investigations that can detect a wide range of organics in complex mixtures, determine the structure of selected molecules, and provide powerful insights into their origin and evolution. Previous studies from remote spectroscopy of the Outer Solar System showed a diverse population of macromolecular species that are likely to include aromatic and conjugated hydrocarbons with varying degrees of methylation and nitrile incorporation. In situ exploration of Titan's upper atmosphere via mass and plasma spectrometry has revealed a complex mixture of organics. Similar material is expected on the Ice Giants, their moons, and other Outer Solar System bodies, where it may subsequently be deposited onto surface ices. It is evident that the detection of organics on other planetary surfaces provides insight into the chemical and geological evolution of a Solar System body of interest and can inform our understanding of its potential habitability. We have developed a prototype two-step laser desorption/ionization time-of-flight mass spectrometer (L2MS) instrument by exploiting the resonance-enhanced desorption of analyte. We have successfully demonstrated the ability of the L2MS to detect hydrocarbons in organically-doped analog minerals, including cryogenic Ocean World-relevant ices and mixtures. The L2MS instrument operates by generating a neutral plume of desorbed analyte with an IR desorption laser pulse, followed at a delay by a ultraviolet (UV) laser pulse, ionizing the plume. Desorption of the analyte, including trace organic species, may be enhanced by selecting the wavelength of the IR desorption laser to coincide with IR absorption features associated with vibration transitions of minerals or organic functional groups. In this effort, a preliminary laser developed for the instrument uses a breadboard mid-infrared (MIR) desorption laser operating at a discrete 3.475 µm wavelength, and a breadboard UV

  8. A unified Fourier theory for time-of-flight PET data

    Science.gov (United States)

    Li, Yusheng; Matej, Samuel; Metzler, Scott D.

    2016-01-01

    Fully 3D time-of-flight (TOF) PET scanners offer the potential of previously unachievable image quality in clinical PET imaging. TOF measurements add another degree of redundancy for cylindrical PET scanners and make photon-limited TOF-PET imaging more robust than non-TOF PET imaging. The data space for 3D TOF-PET data is five-dimensional with two degrees of redundancy. Previously, consistency equations were used to characterize the redundancy of TOF-PET data. In this paper, we first derive two Fourier consistency equations and Fourier-John equation for 3D TOF PET based on the generalized projection-slice theorem; the three partial differential equations (PDEs) are the dual of the sinogram consistency equations and John’s equation. We then solve the three PDEs using the method of characteristics. The two degrees of entangled redundancy of the TOF-PET data can be explicitly elicited and exploited by the solutions of the PDEs along the characteristic curves, which gives a complete understanding of the rich structure of the 3D x-ray transform with TOF measurement. Fourier rebinning equations and other mapping equations among different types of PET data are special cases of the general solutions. We also obtain new Fourier rebinning and consistency equations (FORCEs) from other special cases of the general solutions, and thus we obtain a complete scheme to convert among different types of PET data: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF data. The new FORCEs can be used as new Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. Further, we give a geometric interpretation of the general solutions—the two families of characteristic curves can be obtained by respectively changing the azimuthal and co-polar angles of the biorthogonal coordinates in Fourier space. We conclude the unified Fourier theory by showing that the Fourier consistency equations

  9. Bismuth germanate coupled to near ultraviolet silicon photomultipliers for time-of-flight PET.

    Science.gov (United States)

    Kwon, Sun Il; Gola, Alberto; Ferri, Alessandro; Piemonte, Claudio; Cherry, Simon R

    2016-09-21

    Bismuth germanate (BGO) was a very attractive scintillator in early-generation positron emission tomography (PET) scanners. However, the major disadvantages of BGO are lower light yield and longer rise and decay time compared to currently popular scintillators such as LSO and LYSO. This results in poorer coincidence timing resolution and it has generally been assumed that BGO is not a suitable scintillator for time-of-flight (TOF) PET applications. However, when a 511 keV photon interacts in a scintillator, a number of Cerenkov photons are produced promptly by energetic electrons released by photoelectric or Compton interactions. If these prompt photons can be captured, they could provide a better timing trigger for PET. Since BGO has a high refractive index (increasing the Cerenkov light yield) and excellent optical transparency down to 320 nm (Cerenkov light yield is higher at shorter wavelengths), we hypothesized that the coincidence timing resolution of BGO can be significantly improved by efficient detection of the Cerenkov photons. However, since the number of Cerenkov photons is far less than the number of scintillation photons, and they are more abundant in the UV and blue part of the spectrum, photosensors need to have high UV/blue sensitivity, fast temporal response, and very low noise in order to trigger on the faint Cerenkov signal. In this respect, NUV-HD silicon photomultipliers (SiPMs) (FBK, Trento, Italy) are an excellent fit for our approach. In this study, coincidence events were measured using BGO crystals coupled with NUV-HD SiPMs. The existence and influence of Cerenkov photons on the timing measurements were studied using different configurations to exploit the directionality of the Cerenkov emissions. Coincidence resolving time values (FWHM) of ~270 ps from 2  ×  3  ×  2 mm(3) BGO crystals and ~560 ps from 3  ×  3  ×  20 mm(3) BGO crystals were obtained. To our knowledge, these are the best

  10. Bismuth germanate coupled to near ultraviolet silicon photomultipliers for time-of-flight PET

    Science.gov (United States)

    Kwon, Sun Il; Gola, Alberto; Ferri, Alessandro; Piemonte, Claudio; Cherry, Simon R.

    2016-09-01

    Bismuth germanate (BGO) was a very attractive scintillator in early-generation positron emission tomography (PET) scanners. However, the major disadvantages of BGO are lower light yield and longer rise and decay time compared to currently popular scintillators such as LSO and LYSO. This results in poorer coincidence timing resolution and it has generally been assumed that BGO is not a suitable scintillator for time-of-flight (TOF) PET applications. However, when a 511 keV photon interacts in a scintillator, a number of Cerenkov photons are produced promptly by energetic electrons released by photoelectric or Compton interactions. If these prompt photons can be captured, they could provide a better timing trigger for PET. Since BGO has a high refractive index (increasing the Cerenkov light yield) and excellent optical transparency down to 320 nm (Cerenkov light yield is higher at shorter wavelengths), we hypothesized that the coincidence timing resolution of BGO can be significantly improved by efficient detection of the Cerenkov photons. However, since the number of Cerenkov photons is far less than the number of scintillation photons, and they are more abundant in the UV and blue part of the spectrum, photosensors need to have high UV/blue sensitivity, fast temporal response, and very low noise in order to trigger on the faint Cerenkov signal. In this respect, NUV-HD silicon photomultipliers (SiPMs) (FBK, Trento, Italy) are an excellent fit for our approach. In this study, coincidence events were measured using BGO crystals coupled with NUV-HD SiPMs. The existence and influence of Cerenkov photons on the timing measurements were studied using different configurations to exploit the directionality of the Cerenkov emissions. Coincidence resolving time values (FWHM) of ~270 ps from 2  ×  3  ×  2 mm3 BGO crystals and ~560 ps from 3  ×  3  ×  20 mm3 BGO crystals were obtained. To our knowledge, these are the best

  11. Time-of-flight mass spectrometry of laser exploding foil initiated PETN samples

    Science.gov (United States)

    Fajardo, Mario E.; Molek, Christopher D.; Fossum, Emily C.

    2017-01-01

    We report the results of time-of-flight mass spectrometry (TOFMS) measurements of the gaseous products of thin-film pentaerythritol tetranitrate [PETN, C(CH2NO3)4] samples reacting in vacuo. The PETN sample spots are produced by masked physical vapor deposition [A.S. Tappan, et al., AIP Conf. Proc. 1426, 677 (2012)] onto a first-surface aluminum mirror. A pulsed laser beam imaged through the soda lime glass mirror substrate converts the aluminum layer into a high-temperature high-pressure plasma which initiates chemical reactions in the overlying PETN sample. We had previously proposed [E.C. Fossum, et al., AIP Conf. Proc. 1426, 235 (2012)] to exploit differences in gaseous product chemical identities and molecular velocities to provide a chemically-based diagnostic for distinguishing between "detonation-like" and deflagration responses. Briefly: we expect in-vacuum detonations to produce hyperthermal (v˜10 km/s) thermodynamically-stable products such as N2, CO2, and H2O, and for deflagrations to produce mostly reaction intermediates, such as NO and NO2, with much slower molecular velocities - consistent with the expansion-quenched thermal decomposition of PETN. We observe primarily slow reaction intermediates (NO2, CH2NO3) at low laser pulse energies, the appearance of NO at intermediate laser pulse energies, and the appearance of hyperthemal CO/N2 at mass 28 amu at the highest laser pulse energies. However, these results are somewhat ambiguous, as the NO, NO2, and CH2NO3 intermediates persist and all species become hyperthermal at the higher laser pulse energies. Also, the purported CO/N2 signal at 28 amu may be contaminated by silicon ablated from the glass mirror substrate. We plan to mitigate these problems in future experiments by adopting the "Buelow" sample configuration which employs an intermediate foil barrier to shield the energetic material from the laser and the laser driven plasma [S.J. Buelow, et al., AIP Conf. Proc. 706, 1377 (2003)].

  12. A unified Fourier theory for time-of-flight PET data.

    Science.gov (United States)

    Li, Yusheng; Matej, Samuel; Metzler, Scott D

    2016-01-21

    Fully 3D time-of-flight (TOF) PET scanners offer the potential of previously unachievable image quality in clinical PET imaging. TOF measurements add another degree of redundancy for cylindrical PET scanners and make photon-limited TOF-PET imaging more robust than non-TOF PET imaging. The data space for 3D TOF-PET data is five-dimensional with two degrees of redundancy. Previously, consistency equations were used to characterize the redundancy of TOF-PET data. In this paper, we first derive two Fourier consistency equations and Fourier-John equation for 3D TOF PET based on the generalized projection-slice theorem; the three partial differential equations (PDEs) are the dual of the sinogram consistency equations and John's equation. We then solve the three PDEs using the method of characteristics. The two degrees of entangled redundancy of the TOF-PET data can be explicitly elicited and exploited by the solutions of the PDEs along the characteristic curves, which gives a complete understanding of the rich structure of the 3D x-ray transform with TOF measurement. Fourier rebinning equations and other mapping equations among different types of PET data are special cases of the general solutions. We also obtain new Fourier rebinning and consistency equations (FORCEs) from other special cases of the general solutions, and thus we obtain a complete scheme to convert among different types of PET data: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF data. The new FORCEs can be used as new Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. Further, we give a geometric interpretation of the general solutions--the two families of characteristic curves can be obtained by respectively changing the azimuthal and co-polar angles of the biorthogonal coordinates in Fourier space. We conclude the unified Fourier theory by showing that the Fourier consistency equations are

  13. A highly segmented. Delta. E-time-of-flight wall as forward detector of the 4. pi. -system for charged particles at the SIS/ESR accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Gobbi, A.; Augustinski, G.; Bock, R.; Charity, R.J.; Fan, Z.G.; Freifelder, R.; Grigorian, Y.; Hildenbrand, K.D.; Jeong, S.C.; Marquardt, M.; Reisdorf, W.; Schuell, D.; Sodan, U.; Tanaka, M.H.; Teh, K.M.; Weinert, J.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)); Alard, J.P.; Bastid, N.; Boussange, S.; Crouau, M.; Daudon, F.; Dupieux, P.; Fayard, C.; Fraysse, L.; Jorio, M.; Mayade, S.; Mo

    1992-05-01

    At the SIS/ESR accelerator facility at GSI in Darmstadt the 4{pi}-detector system FOPI is under construction at present. It is designed for the investigation of central collisions of heavy ions in the energy range up to 2xA GeV. As phase I of this detector a forward wall has been built and used in various experiments. It comprises a total number of 764 scintillators with an additional shell of 188 thin {Delta}E-detectors in front of it and covers the full azimuth of the polar angles from 1{sup 0} to 30{sup 0}. The velocity and the nuclear charge of the fragments are determined by a combined time of flight and {Delta}E measurement. (orig.).

  14. Profiling the indole alkaloids in yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Sun, Jianghao; Baker, Andrew; Chen, Pei

    2011-09-30

    An ultra-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry (UPLC/IM-QTOF-MS) method was developed for profiling the indole alkaloids in yohimbe bark. Many indole alkaloids with the yohimbine or ajmalicine core structure, plus methylated, oxidized and reduced species, were characterized. Common fragments and mass differences are described. It was shown that the use of IMS could provide another molecular descriptor, i.e. molecular shape by rotationally averaged collision cross-section; this is of great value for identification of constituents when reference materials are usually not available. Using the combination of high resolution (~40000) accurate mass measurement with time-aligned parallel (TAP) fragmentation, MS(E) (where E represents collision energy), ion mobility mass spectrometry (IMS) and UPLC chromatography, a total 55 indole alkaloids were characterized and a few new indole alkaloids are reported for the first time.

  15. High Spatial Resolution Time-of-Flight Secondary Ion Mass Spectrometry for the Masses: A Novel Orthogonal ToF FIB-SIMS Instrument with In Situ AFM

    Directory of Open Access Journals (Sweden)

    James A. Whitby

    2012-01-01

    Full Text Available We describe the design and performance of an orthogonal time-of-flight (TOF secondary ion mass spectrometer that can be retrofitted to existing focused ion beam (FIB instruments. In particular, a simple interface has been developed for FIB/SEM instruments from the manufacturer Tescan. Orthogonal extraction to the mass analyser obviates the need to pulse the primary ion beam and does not require the use of monoisotopic gallium to preserve mass resolution. The high-duty cycle and reasonable collection efficiency of the new instrument combined with the high spatial resolution of a gallium liquid metal ion source allow chemical observation of features smaller than 50 nm. We have also demonstrated the integration of a scanning probe microscope (SPM operated as an atomic force microscope (AFM within the FIB/SEM-SIMS chamber. This provides roughness information, and will also allow true three dimensional chemical images to be reconstructed from SIMS measurements.

  16. Identification of metabolites of Radix Paeoniae Alba extract in rat bile, plasma and urine by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Zheng-Wei Chen; Ling Tong; Shu-Ming Li; Dong-Xiang Li; Ying Zhang; Shui-Ping Zhou; Yong-Hong Zhu; He Sun

    2014-01-01

    Ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF/MS) was developed to identify the absorbed parent components and metabolites in rat bile, plasma and urine after oral administration of Radix Paeoniae Alba extract (RPAE). A total of 65 compounds were detected in rat bile, plasma and urine samples, including 11 parent compounds and 54 metabolites. The results indicated that glucuronidation, hydroxylation and methylation were the major metabolic pathways of the components of RPAE. Furthermore, the results of this work demonstrated that UPLC-Q-TOF/MS combined with MetaboLynx™ software and mass defect filtering (MDF) could provide unique high throughput capabilities for drug metabolism study, with excellent MS mass accuracy and enhanced MSE data acquisition. With the MSE technique, both precursor and fragment mass spectra can be simultaneously acquired by alternating between high and low collision energy during a single chromatographic run.

  17. Determination of emerging contaminants in wastewater utilizing comprehensive two-dimensional gas-chromatography coupled with time-of-flight mass spectrometry.

    Science.gov (United States)

    Prebihalo, Sarah; Brockman, Adrienne; Cochran, Jack; Dorman, Frank L

    2015-11-06

    An analytical method for identification of emerging contaminants of concern, such as pesticides and organohalogens has been developed and utilized for true discovery-based analysis. In order to achieve the level of sensitivity and selectivity necessary for detecting compounds in complex samples, comprehensive gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) was utilized to analyze wastewater samples obtained from the Pennsylvania State University wastewater treatment facility (WWTF). Determination of emerging contaminants through a process of combining samples which represent "normal background" and comparing this to new samples was developed. Results show the presence of halogenated benzotriazoles in wastewater samples as well as soil samples from Pennsylvania State University agricultural fields. The trace levels of chlorinated benzotriazoles observed in the monitoring wells present on the property indicate likely environmental degradation of the chlorinated benzotriazoles. Preliminary investigation of environmental fate of the substituted benzotriazoles indicates their likely degradation into phenol; an Environmental Protection Agency (USEPA) priority pollutant.

  18. Chemical and biological differentiation of three human breast cancer cell types using time-of-flight secondary ion mass spectrometry (TOF-SIMS)

    Energy Technology Data Exchange (ETDEWEB)

    Kulp, K S; Berman, E F; Knize, M G; Shattuck, D L; Nelson, E J; Wu, L; Montgomery, J L; Felton, J S; Wu, K J

    2006-01-09

    We use Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) to image and classify individual cells based on their characteristic mass spectra. Using statistical data reduction on the large data sets generated during TOF-SIMS analysis, similar biological materials can be differentiated based on a combination of small changes in protein expression, metabolic activity and cell structure. We apply this powerful technique to image and differentiate three carcinoma-derived human breast cancer cell lines (MCF-7, T47D and MDA-MB-231). In homogenized cells, we show the ability to differentiate the cell types as well as cellular compartments (cytosol, nuclear and membrane). These studies illustrate the capacity of TOF-SIMS to characterize individual cells by chemical composition, which could ultimately be applied to detect and identify single aberrant cells within a normal cell population. Ultimately, we anticipate characterizing rare chemical changes that may provide clues to single cell progression within carcinogenic and metastatic pathways.

  19. A Four-Gap Glass-RPC Time-of-Flight Array with 90 ps Time Resolution

    CERN Document Server

    Akindinov, A; Formenti, F; Golovine, V; Klempt, W; Kluge, A; Martemyanov, A N; Martinengo, P; Pinhão, J; Smirnitsky, A V; Spegel, M; Szymanski, P; Zalipska, J

    2001-01-01

    In this paper, we describe the performance of a prototype developed in the context of the ALICE time-of-flight research and development system. The detector module consists of a 32-channel array of 3 x 3 cm2 glass resistive plate chamber (RPC) cells, each of which has four accurately space gaps of 0.3 mm thickness arranged as a pair of double-gap resisitive plate chambers. Operated with a nonflammable gas mixture at atmospheric pressure, the system achieved a time resolution of 90 ps at 98% efficiency with good uniformity and moderate crosstalk. This result shows the feasibility of large-area high-resolution time-of-flight systems based on RPCs at affordable cost.

  20. Calibration of matrix-assisted laser desorption/ionization time-of-flight peptide mass fingerprinting spectra

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter

    2007-01-01

    This chapter describes a number of aspects important for calibration of matrix-assisted laser desorption/ionization time-of-flight spectra prior to peptide mass fingerprinting searches. Both multipoint internal calibration and mass defect-based calibration is illustrated. The chapter describes ho...... potential internal calibrants, like tryptic autodigest peptides and keratin-related peptides, can be identified and used for high-precision calibration. Furthermore, the construction of project/user-specific lists of potential calibrants is illustrated....