Operating Instructions for the Cryogenics in the Liquid Argon Detector at CIEMAT; Operacion de la Criogenia del Detector de Argon Liquido del CIEMAT

Energy Technology Data Exchange (ETDEWEB)

Romero, L; Leal, M D; Prado, M del; Ramirez, J L

2009-12-19

Ciemat has wide experience in designing and developing gaseous particle detectors. It has taken part in the building of experiments for CERN accelerators, constructing shares of the muon chambers for L3 experiment in LEP and CMS experiment in LHC. Recently, new concepts for particle detectors have been developed, as a natural evolution from the ones built at Ciemat. These new radiation detectors use liquefied noble gases as active media. A testing system for these kind of liquefied argon detectors has been built at Ciemat, and includes a supporting cryogenic system for the liquefaction and maintenance of the liquid argon needed for operating the detector. This document describes the technical features of this cryogenic system. Besides the documentation of the cryogenic system, this technical report can be of help for the management and upgrading of the detector. As well as an introduction, the report includes the following chapters: The second one is a description of the cryogenics and gas systems. The third chapter shows the controlling electronics. The fourth chapter deals with the important topic that is security, its systems and protocols. The fifth describes the cryogenic operations possible in this equipment. The report is completed with diagrams, schemes, pictures and tables for the easier management of the setup. (Author)

Monitoring of noble gas radioisotopes in nuclear power plant effluents

International Nuclear Information System (INIS)

Kabat, M.J.

1985-01-01

Monitoring of gaseous radionuclides in the effluents of nuclear facilities is an essential requirement in effluent management programs. Since there is no practical way of removing noble gas radioisotopes from air at release pathways, their accurate monitoring is essential for providing appropriate environmental protection. Emitted γ dose-rate is the limiting factor for concentration-time integral of noble gas in gaseous effluents of reactor facilities. The external exposure to the public from a semi-infinite cloud is directly proportional to both the noble gas isotope concentration and the integrated γ energy per disintegration. Both can be directly measured in gaseous effluent pathways with a suitable detector. The capability of NaI(T1), CaF 2 (Eu) and plastic scintillation detectors to measure the γ-Ci.MeV content of noble gas releases was experimentally evaluated. The combination of CaF 2 (Eu) detector in a pressurized through-flow chamber, with a charge integrating scaler well complied with both γ energy response and detection sensitivity requirements. Noble gas source terms and effluent monitoring criteria are discussed, theoretical and experimental results are presented and a practical, on-line noble gas monitoring system is described

Shock Compression of Liquid Noble Gases to Multi-Mbar Pressures

Science.gov (United States)

Root, Seth

2011-10-01

The high pressure - high temperature behavior of noble gases is of considerable interest because of their use in z-pinch liners for fusion studies and for understanding astrophysical and planetary evolution. However, our understanding of the equation of state (EOS) of the noble gases at extreme conditions is limited. A prime example of this is the liquid xenon Hugoniot. Previous EOS models rapidly diverged on the Hugoniot above 1 Mbar because of differences in the treatment of the electronic contribution to the free energy. Similar divergences are observed for krypton EOS. Combining shock compression experiments and density functional theory (DFT) simulations, we can determine the thermo-physical behavior of matter under extreme conditions. The experimental and DFT results have been instrumental to recent developments in planetary astrophysics and inertial confinement fusion. Shock compression experiments are performed using Sandia's Z-Accelerator to determine the Hugoniot of liquid xenon and krypton in the Mbar regime. Under strong pressure, krypton and xenon undergo an insulator to metal transition. In the metallic state, the shock front becomes reflective allowing for a direct measurement of the sample's shock velocity using laser interferometry. The Hugoniot state is determined using a Monte Carlo analysis method that accounts for systematic error in the standards and for correlations. DFT simulations at these extreme conditions show good agreement with the experimental data - demonstrating the attention to detail required for dealing with elements with relativistic core states and d-state electrons. The results from shock compression experiments and DFT simulations are presented for liquid xenon to 840 GPa and for liquid krypton to 800 GPa, decidedly increasing the range of known behavior of both gases. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company

Some remarks on the use of the effective medium approximation for the resistivity calculations in liquid noble metals

International Nuclear Information System (INIS)

Gorecki, J.

1982-09-01

The application of the effective medium approximation (EMA) to the muffin-tin model of liquid metal is considered. The triple correlation function is included in the expression for electrical resistivity. Good agreement with experimental data can be expected for liquid noble metals. (author)

EDO, Doses to Man and Organs from Reactor Operation Noble Gas and Liquid Waste Release

International Nuclear Information System (INIS)

Rodenas Diago, Jose; Serradell Garcia, Vicente

1983-01-01

1 - Description of problem or function: EDO evaluates individual and collective doses to man from atmospheric releases of noble gases and other gaseous effluents. 2 - Method of solution: The dose calculations are carried out by following the guide- lines of USNRC Regulatory Guide 1.109. Radiation exposure for maximum individuals and population are estimated within 30 km from the nuclear plant. This area is divided into 160 circular trapezoids, to which computations are referred. Four age groups, seven organs for internal dose and two for external dose have been considered. Dose calculations are done through 14 pathways, 7 for liquid effluents, one for noble gases, and 6 for the rest of gaseous effluents. 3 - Restrictions on the complexity of the problem: The following are the maximum dimension sizes preset in the code: 73 radionuclides (other than noble gases); 15 noble gases; 160 circular trapezoids; 31 chemical elements; 4 types of aquatic foods; 15 points of exposure for shorelines; 15 trapezoids influenced by each point; 4 terrestrial food pathways; 100 centres of population. Some of these limits can be varied

EDO, Doses to Man and Organs from Reactor Operation Noble Gas and Liquid Waste Release

Energy Technology Data Exchange (ETDEWEB)

Rodenas Diago, Jose; Serradell Garcia, Vicente [Departamento de Ingenieria Nuclear, Escuela Tecnica Superior de Ingenieros Industriales, Universidad Politecnica, Camino de Vera 2/n Apartado 2012, Valencia (Spain)

1983-10-18

1 - Description of problem or function: EDO evaluates individual and collective doses to man from atmospheric releases of noble gases and other gaseous effluents. 2 - Method of solution: The dose calculations are carried out by following the guide- lines of USNRC Regulatory Guide 1.109. Radiation exposure for maximum individuals and population are estimated within 30 km from the nuclear plant. This area is divided into 160 circular trapezoids, to which computations are referred. Four age groups, seven organs for internal dose and two for external dose have been considered. Dose calculations are done through 14 pathways, 7 for liquid effluents, one for noble gases, and 6 for the rest of gaseous effluents. 3 - Restrictions on the complexity of the problem: The following are the maximum dimension sizes preset in the code: 73 radionuclides (other than noble gases); 15 noble gases; 160 circular trapezoids; 31 chemical elements; 4 types of aquatic foods; 15 points of exposure for shorelines; 15 trapezoids influenced by each point; 4 terrestrial food pathways; 100 centres of population. Some of these limits can be varied.

The development of gaseous detectors with solid photocathodes for low temperature applications

CERN Document Server

Periale, L.; Iacobaeus, C.; Francke, T.; Lund-Jensen, B.; Pavlopoulos, N.; Picchi, P.; Pietropaolo, F.

2004-01-01

There are several applications and fundamental research areas which require the detection of VUV light at cryogenic temperatures. For these applications we have developed and successfully tested special designs of gaseous detectors with solid photocathodes able to operate at low temperatures: sealed gaseous detectors with MgF2 windows and windowless detectors. We have experimentally demonstrated, that both primary and secondary (due to the avalanche multiplication inside liquids) scintillation lights could be recorded by photosensitive gaseous detectors. The results of this work may allow one to significantly improve the operation of some noble liquid gas TPCs.

Characterisation of GERDA Phase-I detectors in liquid argon

Energy Technology Data Exchange (ETDEWEB)

Barnabe Heider, Marik; Schoenert, Stefan [Max-Planck-Institut fuer Kernphysik (Germany); Gusev, Konstantin [Russian Research Center, Kurchatov Institute (Russian Federation); Joint Institute for Nuclear Research (Russian Federation)

2009-07-01

GERDA will search for neutrinoless double beta decay in {sup 76}Ge by submerging bare enriched HPGe detectors in liquid argon. In GERDA Phase-I, reprocessed enriched-Ge detectors, which were previously operated by the Heidelberg-Moscow and IGEX collaborations, and reprocessed natural-Ge detectors from Genius-TF, will be redeployed. We have tested the operation and performance of bare HPGe detectors in liquid nitrogen and in liquid argon over more than three years with three non-enriched p-type prototype detectors. The detector handling and mounting procedures have been defined and the Phase-I detector technology, the low-mass assembly and the long-term stability in liquid argon have been tested successfully. The Phase-I detectors were reprocessed by Canberra Semiconductor NV, Olen, according to their standard technology but without the evaporation of a passivation layer. After their reprocessing, the detectors have been mounted in their low-mass holders and their characterisation in liquid argon performed. The leakage current, the counting characteristics and the efficiency of the detectors have been measured. The testing of the detectors was carried out in the liquid argon test stand of the GERDA underground Detector Laboratory (GDL) at LNGS. The detectors are now stored underground under vacuum until their operation in GERDA.

Near-infrared scintillation of liquid argon

Energy Technology Data Exchange (ETDEWEB)

Alexander, T. [Fermilab; Escobar, C. O. [Campinas State U.; Lippincott, W. H. [Fermilab; Rubinov, P. [Fermilab

2016-03-03

Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

Detectors for Particle Radiation

Science.gov (United States)

Kleinknecht, Konrad

1999-01-01

This textbook provides a clear, concise and comprehensive review of the physical principles behind the devices used to detect charged particles and gamma rays, and the construction and performance of these many different types of detectors. Detectors for high-energy particles and radiation are used in many areas of science, especially particle physics and nuclear physics experiments, nuclear medicine, cosmic ray measurements, space sciences and geological exploration. This second edition includes all the latest developments in detector technology, including several new chapters covering micro-strip gas chambers, silicion strip detectors and CCDs, scintillating fibers, shower detectors using noble liquid gases, and compensating calorimeters for hadronic showers. This well-illustrated textbook contains examples from the many areas in science in which these detectors are used. It provides both a coursebook for students in physics, and a useful introduction for researchers in other fields.

Mount makes liquid nitrogen-cooled gamma ray detector portable

Science.gov (United States)

Fessler, T. E.

1966-01-01

Liquid nitrogen-cooled gamma ray detector system is made portable by attaching the detector to a fixture which provides a good thermal conductive path between the detector and the liquid nitrogen in a dewar flask and a low heat leak path between the detector and the external environment.

Overview of the physical-chemical properties of the noble gases

International Nuclear Information System (INIS)

McKinley, C.

1973-01-01

This paper lists the concentrations of noble gases in the atmosphere and the relative abundance of the stable isotopes. Selected physical properties are tabulated; solubilities of noble gases in water and other liquids, and liquid-vapor equilibria data for binary systems containing a noble gas are presented. Adsorption data are tabulated for illustrative conventional adsorbents and are also presented by a Polanyi correlation. Clathration, biochemical effects, and chemical reactivity are highlighted. Analytical procedures are briefly described. Other relatively non-reactive gases present in the atmosphere in trace quantities are mentioned: methane, carbon tetrafluoride, and sulfur hexafluoride.

Leak detector of liquid sodium

International Nuclear Information System (INIS)

Himeno, Yoshiaki.

1975-01-01

Object: To arrange a cable core connected to a leakage current detector on the outer wall of piping for liquid sodium, devices or the like and apply a voltage to said core and outer wall to quickly and securely detect the leakage of liquid sodium. Structure: A cable, which is composed of metal coating formed of metal material (copper, steel, stainless, etc.) which is apt to be corroded by reaction products of liquid sodium with water and oxygen in air, and metal oxide (such as magnesium oxide, beryllium oxide, aluminum oxide) as an electric insulator is arranged on the outer wall of pipes or devices. In the event sodium is leaked from the pipes or devices, said metal coating and the insulator are corroded, and the leakage of sodium is sensed by a leakage current detector through the core in the cable. (Kamimura, M.)

The Successful Operation of Hole-type Gaseous Detectors at Cryogenic Temperatures

CERN Document Server

Pereiale, L.; Iacobaeus, C.; Francke, T.; Lund-Jensen, B.; Pavlopoulos, P.; Picchi, P.; Pietropaolo, F.; Tokanai, F.

2004-01-01

We have demonstrated that hole-type gaseous detectors, GEMs and capillary plates, can operate up to 77 K. For example, a single capillary plate can operate at gains of above 10E3 in the entire temperature interval between 300 until 77 K. The same capillary plate combined with CsI photocathodes could operate perfectly well at gains (depending on gas mixtures) of 100-1000. Obtained results may open new fields of applications for capillary plates as detectors of UV light and charge particles at cryogenic temperatures: noble liquid TPCs, WIMP detectors or LXe scintillating calorimeters and cryogenic PETs.

The Daya Bay antineutrino detector filling system and liquid mass measurement

Science.gov (United States)

Band, H. R.; Cherwinka, J. J.; Draeger, E.; Heeger, K. M.; Hinrichs, P.; Lewis, C. A.; Mattison, H.; McFarlane, M. C.; Webber, D. M.; Wenman, D.; Wang, W.; Wise, T.; Xiao, Q.

2013-09-01

The Daya Bay Reactor Neutrino Experiment has measured the neutrino mixing angle θ13 to world-leading precision. The experiment uses eight antineutrino detectors filled with 20-tons of gadolinium-doped liquid scintillator to detect antineutrinos emitted from the Daya Bay nuclear power plant through the inverse beta decay reaction. The precision measurement of sin22θ13 relies on the relative antineutrino interaction rates between detectors at near (400 m) and far (roughly 1.8 km) distances from the nuclear reactors. The measured interaction rate in each detector is directly proportional to the number of protons in the liquid scintillator target. A precision detector filling system was developed to simultaneously fill the three liquid zones of the antineutrino detectors and measure the relative target mass between detectors to < 0.02%. This paper describes the design, operation, and performance of the system and the resulting precision measurement of the detectors' target liquid masses.

Study of Thermodynamics of Liquid Noble-Metals Alloys Through a Pseudopotential Theory

International Nuclear Information System (INIS)

Vora, Aditya M.

2010-01-01

The Gibbs-Bogoliubov (GB) inequality is applied to investigate the thermodynamic properties of some equiatomic noble metal alloys in liquid phase such as Au-Cu, Ag-Cu, and Ag-Au using well recognized pseudopotential formalism. For description of the structure, well known Percus-Yevick (PY) hard sphere model is used as a reference system. By applying a variation method the best hard core diameters have been found which correspond to minimum free energy. With this procedure the thermodynamic properties such as entropy and heat of mixing have been computed. The influence of local field correction function viz; Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F), and Sarkar et al. (S) is also investigated. The computed results of the excess entropy compares favourably in the case of liquid alloys while the agreement with experiment is poor in the case of heats of mixing. This may be due to the sensitivity of the heats of mixing with the potential parameters and the dielectric function. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Radioactive flow detectors: liquid or solid scintillators

International Nuclear Information System (INIS)

Reich, A.R.

1983-01-01

During the past five years, two schools of thought have emerged producing two different types of radio-HPLC detectors. Based on the naphthalene-in-the-vial principle, manufacturers have developed heterogeneous scintillation detectors. In these detectors the anthracene or naphthalene crystals are replaced by other scintillators. In order to avoid dead space and turbulence, a narrow diameter tube is used, either straight, or more popularly formed into a coil or a 'U' as the cell. To optimize light transmission to the photomultiplier tubes, mirrors are used. Due to limiting factors in this technique the counting efficiency for tritium is below the 10 percent level. The other school of radio-HPLC detectors based their design on classical liquid scintillation counting technology. In a homogeneous detector, the effluent from the HPLC system is mixed with a suitable liquid scintillator before entering the counting cell. The cell design is typically a flat glass or Teflon coil tightly sandwiched between two photomultiplier tubes, making good optical contact without the use of mirrors. Depending on the chromatographic effluent, 3 H efficiencies between 25 to 50 percent, and 14 C counting efficiencies up to 85 percent can be achieved

A New GEM-like Imaging Detector with Electrodes Coated with Resistive Layers

CERN Document Server

Di Mauro, Antonio; Martinengo, Paolo; Napri, Eugenio; Peskov, Vladimir; Periale, Luciano; Picchi, P.; Pietropaolo, Francesco; Rodionov, I.

We have developed and tested several prototypes of GEM-like detectors with electrodes coated with resistive layers: CuO or CrO. These detectors can operate stably at gains close to 10E5 and they are very robust. We discovered that the cathodes of these detectors could be coated by CsI layers and in such a way the detectors gain high efficiency for the UV photons. We also demonstrated that such detectors can operate stably in the cascade mode and high overall gains (~10E6) are reachable. This opens applications in several areas, for example in RICH or in noble liquid TPCs. Results from the first applications of these devices for UV photon detection at room and cryogenic temperatures are given.

First observation of liquid-xenon proportional electroluminescence in THGEM holes

International Nuclear Information System (INIS)

Arazi, L; Itay, R; Landsman, H; Levinson, L; Pasmantirer, B; Rappaport, M L; Vartsky, D; Breskin, A; Coimbra, A E C

2013-01-01

Radiation-induced proportional-electroluminescence UV signals, emitted from the holes of a Thick Gas Electron Multiplier (THGEM) electrode immersed in liquid xenon, were recorded with a PMT for the first time. Significant photon yields were observed with gamma photons and alpha particles using a 0.4 mm thick electrode with 0.3 mm diameter holes; at 2 kV across the THGEM the photon yield was estimated to be ∼ 600 UV photons/electron over 4π. This may pave the way towards the realization of novel single-phase noble-liquid radiation detectors incorporating liquid hole-multipliers (LHM); their concept is presented

Liquid Scintillation Detectors for High Energy Neutrinos

International Nuclear Information System (INIS)

Smith, Stefanie N.; Learned, John G.

2010-01-01

Large open volume (not segmented) liquid scintillation detectors have been generally dedicated to low energy neutrino measurements, in the MeV energy region. We describe the potential employment of large detectors (>1 kiloton) for studies of higher energy neutrino interactions, such as cosmic rays and long-baseline experiments. When considering the physics potential of new large instruments the possibility of doing useful measurements with higher energy neutrino interactions has been overlooked. Here we take into account Fermat's principle, which states that the first light to reach each PMT will follow the shortest path between that PMT and the point of origin. We describe the geometry of this process, and the resulting wavefront, which we are calling the 'Fermat surface', and discuss methods of using this surface to extract directional track information and particle identification. This capability may be demonstrated in the new long-baseline neutrino beam from Jaeri accelerator to the KamLAND detector in Japan. Other exciting applications include the use of Hanohano as a movable long-baseline detector in this same beam, and LENA in Europe for future long-baseline neutrino beams from CERN. Also, this methodology opens up the question as to whether a large liquid scintillator detector should be given consideration for use in a future long-baseline experiment from Fermilab to the DUSEL underground laboratory at Homestake.

Development and first tests of GEM-like detectors with resistive electrodes

CERN Document Server

Peskov, Vladimir; Centro, Sandro; Di Mauro, A; Lund-Jensen, B; Martinengo, P; Nappi, E; Oliveira, R; Pietropaolo, F; Picchi, P; Periale, L; Rodionov, I; Ventura, Sandro

2007-01-01

We have developed and tested several prototypes of GEM-like detectors with electrodes coated with resistive layers or completely made of resistive materials. These detectors can operate stably at gains close to 105. The resistive layers limit the energy of discharges appearing at higher gains thus making the detectors very robust. We demonstrated that the cathodes of some of these detectors could be coated by CsI or SbCs layers to enhance the detection efficiency for the UV and visible photons. We also discovered that such detectors can operate stably in the cascade mode and high overall gains ($~10^{6}$) are reachable. Applications in several areas, for example in RICH or in noble liquid TPCs are therefore possible. The first results from the detection of UV photons at room and cryogenic temperatures will be given.

Detector for the liquid carried over in a gas

International Nuclear Information System (INIS)

Delisle, J.P.; Eperonnat, P.; Lions, N.

1965-01-01

This report describes an optical detector for the detection of a liquid carried over by a gas. The device is sensitive to a cumulated quantity of liquid equal to a few cubic millimetres and is capable of operating an alarm from a distance. The prototype was constructed and tested as detector for the oil leaking in the argon compressed by a diaphragm compressor. A patent for this apparatus under the number: P.V.954.703, has been deposited on 22.11.1963. (authors) [fr

The Liquid Argon Calorimeter system for the SLC Large Detector

International Nuclear Information System (INIS)

Haller, G.M.; Fox, J.D.; Smith, S.R.

1988-09-01

In this paper the physical packaging and the logical organization of the Liquid Argon Calorimeter (LAC) electronics system for the Stanford Linear Collider Large Detector (SLD) at SLAC are described. This system processes signals from approximately 44,000 calorimeter towers and is unusual in that most electronic functions are packaged within the detector itself as opposed to an external electronics support rack. The signal path from the towers in the liquid argon through the vacuum to the outside of the detector is explained. The organization of the control logic, analog electronics, power regulation, analog-to-digital conversion circuits, and fiber optic drivers mounted directly on the detector are described. Redundancy considerations for the electronics and cooling issues are discussed. 12 refs., 5 figs

Liquid nitrogen enhancement of alpha particle tracks in a polycarbonate detector

International Nuclear Information System (INIS)

Pilione, L.J.

1977-01-01

Makrofol-E polycarbonate detectors were exposed to 1 to 3 MeV alpha particles and subsequently immersed in liquid nitrogen for various periods of time. The influence of the liquid nitrogen on the track recording properties of the detector has been found by measuring the track densities and diameters. Track densities increase with immersion time with a maximum gain of approximately 9% after 1200 min in liquid nitrogen. Track enhancement decreases with waiting time between the end of alpha particle exposure and the beginning of liquid nitrogen immersion. Track diameters decrease with time after passage of the particles and this process is accelerated by immersion in liquid nitrogen. (author)

NEST: a comprehensive model for scintillation yield in liquid xenon

Energy Technology Data Exchange (ETDEWEB)

Szydagis, M; Barry, N; Mock, J; Stolp, D; Sweany, M; Tripathi, M; Uvarov, S; Walsh, N; Woods, M [University of California, Davis, One Shields Ave., Davis, CA 95616 (United States); Kazkaz, K, E-mail: mmszydagis@ucdavis.edu [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States)

2011-10-15

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

NEST: a comprehensive model for scintillation yield in liquid xenon

International Nuclear Information System (INIS)

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

2011-01-01

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

The automatic liquid nitrogen filling system for GDA detectors

Indian Academy of Sciences (India)

. Abstract. An indigenously developed automatic liquid nitrogen (LN2) filling system has been installed in gamma detector array (GDA) facility at Nuclear Science Centre. Electro-pneumatic valves are used for filling the liquid nitrogen into the ...

Liquid-Xe detector for contraband detection

Energy Technology Data Exchange (ETDEWEB)

Vartsky, D., E-mail: david.vartsky@weizmann.ac.il [Weizmann Institute of Science, Rehovot 76100 (Israel); Israelashvili, I. [Weizmann Institute of Science, Rehovot 76100 (Israel); Nuclear Research Center of Negev (NRCN), Beer-Sheva 9001 (Israel); Cortesi, M. [National Superconducting Cyclotron Laboratory, East Lansing 48823, MI (United States); Arazi, L.; Coimbra, A.E.; Moleri, L.; Erdal, E.; Bar, D.; Rappaport, M.; Shchemelinin, S. [Weizmann Institute of Science, Rehovot 76100 (Israel); Caspi, E.N. [Nuclear Research Center of Negev (NRCN), Beer-Sheva 9001 (Israel); Aviv, O. [Soreq NRC, Yavne 81800 (Israel); Breskin, A. [Weizmann Institute of Science, Rehovot 76100 (Israel)

2016-07-11

We describe progress made with a liquid-Xe (LXe) detector coupled to a gaseous photomultiplier (GPM), for combined imaging and spectroscopy of fast neutrons and gamma-rays in the MeV range. The purpose of this detector is to enable the detection of hidden explosives and fissile materials in cargo and containers. The expected position resolution is about 2 m and 3.5 mm for fast neutrons and gamma-rays, respectively. Experimental results obtained using an {sup 241}Am source yielded energy and time resolutions of 11% and 1.2 ns RMS, respectively. Initial results obtained with the position-sensitive GPM are presented.

Measuring fast neutrons with large liquid scintillation detector for ultra-low background experiments

Energy Technology Data Exchange (ETDEWEB)

Zhang, C. [Department of Physics, The University of South Dakota, Vermillion, SD 57069 (United States); College of Sciences, China Three Gorges University, Yichang 443002 (China); Mei, D.-M., E-mail: dongming.mei@usd.edu [Department of Physics, The University of South Dakota, Vermillion, SD 57069 (United States); Davis, P.; Woltman, B. [Department of Physics, The University of South Dakota, Vermillion, SD 57069 (United States); Gray, F. [Department of Physics and Computational Science, Regis University, Denver, CO 80221 (United States)

2013-11-21

We developed a 12-liter volume neutron detector filled with the liquid scintillator EJ301 that measures neutrons in an underground laboratory where dark matter and neutrino experiments are located. The detector target is a cylindrical volume coated on the inside with reflective paint (95% reflectivity) that significantly increases the detector's light collection. We demonstrate several calibration techniques using point sources and cosmic-ray muons for energies up to 20 MeV for this large liquid scintillation detector. Neutron–gamma separation using pulse shape discrimination with a few MeV neutrons to hundreds of MeV neutrons is shown for the first time using a large liquid scintillator.

A new liquid xenon scintillation detector for positron emission tomography

International Nuclear Information System (INIS)

Chepel, V.Yu.

1993-01-01

A new positron-sensitive detector of annihilation photons filled with liquid xenon is proposed for positron emission tomography. Simultaneous detection of both liquid xenon scintillation and ionization current produces a time resolution of < 1 ns and a position resolution in the tangential direction of the tomograph ring is ∼ 1 mm and in the radial direction is ∼ 5 mm. The advantages of a tomograph with new detectors are discussed. New algorithms of Compton scattering can be used. (author)

New scintillating media based on liquid crystals for particle detectors

International Nuclear Information System (INIS)

Barnik, M.I.; Yudin, S.G.; Vasil'chenko, V.G.; Golovkin, S.V.; Medvedkov, A.M.; Solovjev, A.S.

2000-01-01

The study results of optical, photoluminiscent and scintillation properties of a liquid crystal 4-pentyl-4'-cyanobiphenyl are presented. The scintillation light output of this liquid crystal is about 35% of crystal anthracene, its main decay time constants are 4 and 14 ns, and the maximum of light emission spectrum is about 400 nm. The light output of a dissolution of green emitting light scintillation dopant R6 in the liquid crystal is about 120% of crystal anthracene. The light output of the frozen dissolution measured at -112 deg. C is about 2.5 times higher as observed at +20 deg. C. In the uniaxially oriented liquid crystal, the predominant intensity direction of emitted light is pointed perpendicular to the liquid crystal director and an appreciable part of the emitted light is elliptically polarized. The possibility to use scintillation properties of liquid crystals is considered both for the improvement of existing particle detector characteristics and for the creation of new gated particle detectors

New scintillating media based on liquid crystals for particle detectors

CERN Document Server

Barnik, M I; Vasilchenko, V G; Golovkin, S V; Medvedkov, A M; Soloviev, A S

2000-01-01

The study results of optical, photoluminiscent and scintillation properties of a liquid crystal 4-pentyl-4'-cyanobiphenyl are presented. The scintillation light output of this liquid crystal is about 35% of crystal anthracene, its main decay time constants are 4 and 14 ns, and the maximum of light emission spectrum is about 400 nm. The light output of a dissolution of green emitting light scintillation dopant R6 in the liquid crystal is about 120% of crystal anthracene. The light output of the frozen dissolution measured at -112 deg. C is about 2.5 times higher as observed at +20 deg. C. In the uniaxially oriented liquid crystal, the predominant intensity direction of emitted light is pointed perpendicular to the liquid crystal director and an appreciable part of the emitted light is elliptically polarized. The possibility to use scintillation properties of liquid crystals is considered both for the improvement of existing particle detector characteristics and for the creation of new gated particle detectors.

An efficient energy response model for liquid scintillator detectors

Science.gov (United States)

Lebanowski, Logan; Wan, Linyan; Ji, Xiangpan; Wang, Zhe; Chen, Shaomin

2018-05-01

Liquid scintillator detectors are playing an increasingly important role in low-energy neutrino experiments. In this article, we describe a generic energy response model of liquid scintillator detectors that provides energy estimations of sub-percent accuracy. This model fits a minimal set of physically-motivated parameters that capture the essential characteristics of scintillator response and that can naturally account for changes in scintillator over time, helping to avoid associated biases or systematic uncertainties. The model employs a one-step calculation and look-up tables, yielding an immediate estimation of energy and an efficient framework for quantifying systematic uncertainties and correlations.

Large-Area Liquid Scintillation Detector Slab

International Nuclear Information System (INIS)

Crouch, M. F.; Gurr, H. S.; Hruschka, A. A.; Jenkins, T. L.; Kropp, W.; Reines, F.; Sobel, H.; Hruschka, A. A.

1966-01-01

A low-cost detector 18' x 2' x 5' has been developed for an underground cosmic ray neutrino experiment. The liquid employed is a high-clarity mineral oil-based mixture, and light is guided to the ends of the detector by total internal reflection at the surface of the Lucite container. Signals from 2 five-inch photomultipliers at each end give energy and event location for single penetrating particles, with relatively good discrimination against natural radioactivity by virtue of the substantial thickness. Data are presented on the response function of the tank, energy resolution, rates and thresholds. A number of modifications that have been tried are also described

Operating the GridPix detector in dark matter search experiments

NARCIS (Netherlands)

Schön, R.; Alfonsi, M.; Hemink, G.; Decowski, M.P.; van Bakel, N.; van der Graaf, H.

2013-01-01

The DARWIN (dark matter WIMP search with noble liquids) design study aims to use liquid argon and liquid xenon targets to look for nuclear recoils due to weakly interacting massive particles (WIMPs). To measure the recoil energy in dual-phase noble gas time projection chambers the combination of

Is the thermodynamic behavior of the noble fluids consistent with the principle of corresponding states?

NARCIS (Netherlands)

Kulinskii, V.L.; Malomuzh, N.P.; Matvejchuk, O.I.

2009-01-01

The applicability of the Principle of Corresponding States (PCS) for the noble fluids is discussed. We give the thermodynamic evidence for the dimerization of the liquid phase in heavy noble gases like argon, krypton etc. which manifests itself in deviations from the PCS. The behavior of the

Particle Detectors: Research and Development at CERN

International Nuclear Information System (INIS)

Fabjan, C. W.

2008-01-01

Over the past 15 years a worldwide Detector R and D Programme has made the LHC experiments possible. These experiments operate at a new level of event rate and detection capabilities. Based on these advances, Detector R and D is continuing at CERN in close collaboration with University and Research Institutes. Several main directions are being pursued for solid-state and gaseous tracking devices, advanced crystal and noble liquid calorimetry, particle identification methods, and advanced signal-processing techniques. This effort is directed towards experiments at even higher collision rates at the LHC, the requirements for the next generation of linear electron-positron colliders and for applications outside particle physics, such as medical diagnostics instrumentation. We shall illustrate this challenging, stimulating and creative programme with examples and show how these developments are taking place in close collaboration between CERN and institutions around the globe

Wide range noble gas radiation monitor

International Nuclear Information System (INIS)

Kuhlman, H.S. III; Wyvill, J.R.

1984-01-01

The present invention contemplates providing a sample system for effluent from a nuclear process wherein the effluent in a first mode passes through a sample chamber whose noble gases are quantitatively detected. The sample of the first mode is continued until the detector count rate reaches a predetermined maximum. The detector establishes a control signal which is applied to terminate the first mode effluent flow to the chamber, evacuate the chamber to a predetermined value of vacuum and connect the effluent into the sample chamber with a predetermined mode of flow rate different from the rate of the first mode to establish a sample concentration in the chamber within the range of the detector. A subsequent predetermined minimum rate will generate a signal to reconnect the sample chamber to the first mode connection and thereby cycle the system back to its first mode of operation

Silicon surface barrier detectors used for liquid hydrogen density measurement

Science.gov (United States)

James, D. T.; Milam, J. K.; Winslett, H. B.

1968-01-01

Multichannel system employing a radioisotope radiation source, strontium-90, radiation detector, and a silicon surface barrier detector, measures the local density of liquid hydrogen at various levels in a storage tank. The instrument contains electronic equipment for collecting the density information, and a data handling system for processing this information.

ABOUT THE POSSIBLE ROLE OF HYDROCARBON LAKES IN THE ORIGIN OF TITAN'S NOBLE GAS ATMOSPHERIC DEPLETION

International Nuclear Information System (INIS)

Cordier, D.; Mousis, O.; Lunine, J. I.; Lebonnois, S.; Lavvas, P.; Lobo, L. Q.; Ferreira, A. G. M.

2010-01-01

An unexpected feature of Titan's atmosphere is the strong depletion in primordial noble gases revealed by the Gas Chromatograph Mass Spectrometer aboard the Huygens probe during its descent on 2005 January 14. Although several plausible explanations have already been formulated, no definitive response to this issue has yet been found. Here, we investigate the possible sequestration of these noble gases in the liquid contained in lakes and wet terrains on Titan and the consequences for their atmospheric abundances. Considering the atmosphere and the liquid existing on the soil as a whole system, we compute the abundance of each noble gas relative to nitrogen. To do so, we make the assumption of thermodynamic equilibrium between the liquid and the atmosphere, the abundances of the different constituents being determined via regular solution theory. We find that xenon's atmospheric depletion can be explained by its dissolution at ambient temperature in the liquid presumably present on Titan's soil. In the cases of argon and krypton, we find that the fractions incorporated in the liquid are negligible, implying that an alternative mechanism must be invoked to explain their atmospheric depletion.

Consistent measurements comparing the drift features of noble gas mixtures

CERN Document Server

Becker, U; Fortunato, E M; Kirchner, J; Rosera, K; Uchida, Y

1999-01-01

We present a consistent set of measurements of electron drift velocities and Lorentz deflection angles for all noble gases with methane and ethane as quenchers in magnetic fields up to 0.8 T. Empirical descriptions are also presented. Details on the World Wide Web allow for guided design and optimization of future detectors.

Exotic species with explicit noble metal-noble gas-noble metal linkages.

Science.gov (United States)

Moreno, Norberto; Restrepo, Albeiro; Hadad, C Z

2018-02-14

We present a study of the isoelectronic Pt 2 Ng 2 F 4 and [Au 2 Ng 2 F 4 ] 2+ species with noble gas atoms (Ng = Kr, Xe, Rn) acting as links bridging the two noble metal atoms. The stability of the species is investigated using several thermodynamic, kinetic and reactivity indicators. The results are compared against [AuXe 4 ] 2+ , which is thermodynamically unstable in the gas phase but is stabilized in the solid state to the point that it has been experimentally detected as [AuXe 4 ](Sb 2 F 11 ) 2 (S. Seidel and K. Seppelt, Science, 2000, 290, 117-118). Our results indicate that improving upon [AuXe 4 ] 2+ , these exotic combinations between the a priori non-reactive noble metals and noble gases lead to metastable species, and, therefore, they have the possibility of existing in the solid state under adequate conditions. Our calculations include accurate energies and geometries at both the CCSD/SDDALL and MP2/SDDALL levels. We offer a detailed description of the nature of the bonding interactions using orbital and density-based analyses. The computational evidence suggests partially covalent and ionic interactions as the stabilization factors.

Development of detection techniques for the Swedish noble gas sampler

International Nuclear Information System (INIS)

Ringbom, A.

1998-11-01

A short review on the radioactive properties of noble gas isotopes relevant for monitoring of nuclear activities is given, together with a brief discussion of the existing systems for detection of radioactive noble gases. A 4π detection system to be used in the automatic version of the Swedish noble gas sampling device is described. Monte Carlo calculations of the total gamma and beta efficiency for different detector designs have been performed, together with estimates of the resulting minimum detectable concentration (MDC). The estimated MDC values for detection of the 133g Xe 81 keV and the 135g Xe 250 keV gamma lines are around 0.3 mBq/m 3 in both cases. This is a factor of three lower than the detection limit required for a sampling station in the Comprehensive Nuclear-Test-Ban Treaty monitoring network. The possibility to modify the system to detect 85 Kr is also discussed

Development of detection techniques for the Swedish noble gas sampler

Energy Technology Data Exchange (ETDEWEB)

Ringbom, A

1998-11-01

A short review on the radioactive properties of noble gas isotopes relevant for monitoring of nuclear activities is given, together with a brief discussion of the existing systems for detection of radioactive noble gases. A 4{pi} detection system to be used in the automatic version of the Swedish noble gas sampling device is described. Monte Carlo calculations of the total gamma and beta efficiency for different detector designs have been performed, together with estimates of the resulting minimum detectable concentration (MDC). The estimated MDC values for detection of the {sup 133g}Xe 81 keV and the {sup 135g}Xe 250 keV gamma lines are around 0.3 mBq/m{sup 3} in both cases. This is a factor of three lower than the detection limit required for a sampling station in the Comprehensive Nuclear-Test-Ban Treaty monitoring network. The possibility to modify the system to detect {sup 85}Kr is also discussed 27 refs, 13 figs, 3 tabs

High purity liquid phase epitaxial gallium arsenide nuclear radiation detector

International Nuclear Information System (INIS)

Alexiev, D.; Butcher, K.S.A.

1991-11-01

Surface barrier radiation detector made from high purity liquid phase epitaxial gallium arsenide wafers have been operated as X- and γ-ray detectors at various operating temperatures. Low energy isotopes are resolved including 241 Am at 40 deg C. and the higher gamma energies of 235 U at -80 deg C. 15 refs., 1 tab., 6 figs

Development of the liquid level meters for the PandaX dark matter detector

International Nuclear Information System (INIS)

Hu Jie; Gong Haowei; Lin Qing; Ni Kaixuan; Wei Yuehuan; Xiao Mengjiao; Xiao Xiang; Zhao Li; Tan Andi

2014-01-01

The two-phase xenon detector is at the frontier of dark matter direct search. This kind of detector uses liquid xenon as the sensitive target and is operated in two-phase (liquid/gas) mode, where the liquid level needs to be monitored and controlled in sub-millimeter precision. In this paper, we present a detailed design and study of two kinds of level meters for the PandaX dark matter detector. The long level meter is used to monitor the overall liquid level while short level meters are used to monitor the inclination of the detector. These level meters are cylindrical capacitors that are custom-made from two concentric metal tubes. Their capacitance values are read out by a universal transducer interface chip and are recorded by the PandaX slow control system. We present the developments that lead to level meters with long-term stability and sub-millimeter precision. Fluctuations (standard deviations) of less than 0.02 mm for the short level meters and less than 0.2 mm for the long level meter were achieved during a few days of test operation. (authors)

Detector for the liquid carried over in a gas; Detecteur d'entrainement de liquide dans un gaz

Energy Technology Data Exchange (ETDEWEB)

Delisle, J P; Eperonnat, P; Lions, N [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

1965-07-01

This report describes an optical detector for the detection of a liquid carried over by a gas. The device is sensitive to a cumulated quantity of liquid equal to a few cubic millimetres and is capable of operating an alarm from a distance. The prototype was constructed and tested as detector for the oil leaking in the argon compressed by a diaphragm compressor. A patent for this apparatus under the number: P.V.954.703, has been deposited on 22.11.1963. (authors) [French] Ce rapport decrit un detecteur optique d'entrainement de liquide dans un gaz, sensible a une quantite cumulee de liquide entraine egale a quelques millimetres cubes. L'appareil peut actionner une alarme a distance. Le prototype a ete construit et essaye comme detecteur de fuites d'huile dans l'argon refoule par un compresseur a membranes. Une demande de brevet a ete deposee pour cet appareil sous le numero: P.V.954.703, le 22.11.1963. (auteur)

Low energy neutrino astronomy with the large liquid-scintillation detector LENA

International Nuclear Information System (INIS)

Undagoitia, T Marrodan; Feilitzsch, F von; Goeger-Neff, M; Hochmuth, K A; Oberauer, L; Potzel, W; Wurm, M

2006-01-01

The detection of low energy neutrinos in a large liquid scintillation detector may provide further important information on astrophysical processes as supernova physics, solar physics and elementary particle physics as well as geophysics. In this contribution, a new project for Low Energy Neutrino Astronomy (LENA) consisting of a 50 kt scintillation detector is presented

Resonance ionization spectroscopy: Counting noble gas atoms

International Nuclear Information System (INIS)

Hurst, G.S.; Payne, M.G.; Chen, C.H.; Willis, R.D.; Lehmann, B.E.; Kramer, S.D.

1981-01-01

The purpose of this paper is to describe new work on the counting of noble gas atoms, using lasers for the selective ionization and detectors for counting individual particles (electrons or positive ions). When positive ions are counted, various kinds of mass analyzers (magnetic, quadrupole, or time-of-flight) can be incorporated to provide A selectivity. We show that a variety of interesting and important applications can be made with atom-counting techniques which are both atomic number (Z) and mass number (A) selective. (orig./FKS)

One parameter model potential for noble metals

International Nuclear Information System (INIS)

Idrees, M.; Khwaja, F.A.; Razmi, M.S.K.

1981-08-01

A phenomenological one parameter model potential which includes s-d hybridization and core-core exchange contributions is proposed for noble metals. A number of interesting properties like liquid metal resistivities, band gaps, thermoelectric powers and ion-ion interaction potentials are calculated for Cu, Ag and Au. The results obtained are in better agreement with experiment than the ones predicted by the other model potentials in the literature. (author)

Cross-Calibration of Secondary Electron Multiplier in Noble Gas Analysis

Science.gov (United States)

Santato, Alessandro; Hamilton, Doug; Deerberg, Michael; Wijbrans, Jan; Kuiper, Klaudia; Bouman, Claudia

2015-04-01

The latest generation of multi-collector noble gas mass spectrometers has decisively improved the precision in isotopic ratio analysis [1, 2] and helped the scientific community to address new questions [3]. Measuring numerous isotopes simultaneously has two significant advantages: firstly, any fluctuations in signal intensity have no effect on the isotope ratio and secondly, the analysis time is reduced. This particular point becomes very important in static vacuum mass spectrometry where during the analysis, the signal intensity decays and at the same time the background increases. However, when multi-collector analysis is utilized, it is necessary to pay special attention to the cross calibration of the detectors. This is a key point in order to have accurate and reproducible isotopic ratios. In isotope ratio mass spectrometry, with regard to the type of detector (i.e. Faraday or Secondary Electron Multiplier, SEM), analytical technique (TIMS, MC-ICP-MS or IRMS) and isotope system of interest, several techniques are currently applied to cross-calibrate the detectors. Specifically, the gain of the Faraday cups is generally stable and only the associated amplifier must be calibrated. For example, on the Thermo Scientific instrument control systems, the 1011 and 1012 ohm amplifiers can easily be calibrated through a fully software controlled procedure by inputting a constant electric signal to each amplifier sequentially [4]. On the other hand, the yield of the SEMs can drift up to 0.2% / hour and other techniques such as peak hopping, standard-sample bracketing and multi-dynamic measurement must be used. Peak hopping allows the detectors to be calibrated by measuring an ion beam of constant intensity across the detectors whereas standard-sample bracketing corrects the drift of the detectors through the analysis of a reference standard of a known isotopic ratio. If at least one isotopic pair of the sample is known, multi-dynamic measurement can be used; in this

Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

Energy Technology Data Exchange (ETDEWEB)

Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, William Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Montana, Missoula, MT (United States)

2015-09-01

This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

Determination of noble metals in geological materials by radiochemical neutron-activation analysis

International Nuclear Information System (INIS)

Ahmad, I.; Ahmad, S.; Morris, D.F.C.

1977-01-01

A method for the determination of platinum, palladium, gold and iridium in geological materials following activation with thermal neutrons is described. Radionuclides formed from the elements are separated by a scheme based largely on liquid-liquid extractions. The procedure has been applied to the analysis of US Geological Survey standard rocks and to studies of the distribution of the noble metals in lateritic nickel ores. (author)

Noble Gases

Science.gov (United States)

Podosek, F. A.

2003-12-01

The noble gases are the group of elements - helium, neon, argon, krypton, xenon - in the rightmost column of the periodic table of the elements, those which have "filled" outermost shells of electrons (two for helium, eight for the others). This configuration of electrons results in a neutral atom that has relatively low electron affinity and relatively high ionization energy. In consequence, in most natural circumstances these elements do not form chemical compounds, whence they are called "noble." Similarly, much more so than other elements in most circumstances, they partition strongly into a gas phase (as monatomic gas), so that they are called the "noble gases" (also, "inert gases"). (It should be noted, of course, that there is a sixth noble gas, radon, but all isotopes of radon are radioactive, with maximum half-life a few days, so that radon occurs in nature only because of recent production in the U-Th decay chains. The factors that govern the distribution of radon isotopes are thus quite different from those for the five gases cited. There are interesting stories about radon, but they are very different from those about the first five noble gases, and are thus outside the scope of this chapter.)In the nuclear fires in which the elements are forged, the creation and destruction of a given nuclear species depends on its nuclear properties, not on whether it will have a filled outermost shell when things cool off and nuclei begin to gather electrons. The numerology of nuclear physics is different from that of chemistry, so that in the cosmos at large there is nothing systematically special about the abundances of the noble gases as compared to other elements. We live in a very nonrepresentative part of the cosmos, however. As is discussed elsewhere in this volume, the outstanding generalization about the geo-/cosmochemistry of the terrestrial planets is that at some point thermodynamic conditions dictated phase separation of solids from gases, and that the

Recovery of noble metals from HLLW using photocatalytic reduction

International Nuclear Information System (INIS)

Nishi, T.; Uetake, N.; Kawamura, F.; Yusa, H.

1987-01-01

In high-level liquid waste (HLLW) from fuel reprocessing plants, noble metals (palladium, rhodium, and ruthenium), which account for ∼ 10 wt% of fission products, exist as ions. These metals are very useful as catalytic material in automobile exhaust systems and other chemical processes, but they are rare in nature, making their recovery from fission products highly desirable. The ions of noble metals in solution have the feature that their reduction potential from ion to metal is relatively high compared with that of other fission product ions, so they can be selectively separated as a metal by a reduction process. The authors think a photoreduction process using a photocatalysts, which functions as photon-electron conversion agent, is suitable for the recovery of noble metals from HLLW for three reasons: (1) this process uses no reduction agents, which usually degrade the nitric acid, so that coprecipitation of other fission products does not occur. (2) The reactions are induced by light, which does not contaminate the reaction system, and in contrast with ordinary photo-redox reactions, the quantum yield is quite high. (3) As the photocatalyst does not change in the reaction, it can be used again and again. The report shows the results of fundamental experiments on the application of photocatalytic reduction to the recovery of noble metal ions in nitric acid solution

ArgonCube: a Modular Approach for Liquid Argon TPC Neutrino Detectors for Near Detector Environments

CERN Document Server

Auger, M; Sinclair, JR

2017-01-01

Liquid Argon Time Projection Chambers (LAr TPCs) are an ideal detector candidate for future neutrino oscillation physics experiments, underground neutrino observatories and proton decay searches. A large international project based on this technology is currently under consideration at the future LBNF/DUNE facility in the United States. That particular endeavor would be on the very large mass scale of 40~kt. Following diverse and long standing R\\&D work conducted over several years, with contributions from international collaborators, we propose a novel LAr TPC based on a fully-modular, innovative design, ArgonCube. ArgonCube will demonstrate that LAr TPCs are a viable detector technology for high-energy and high-multiplicity environments, such as the DUNE near detector. Necessary R\\&D work is proceeding along two main pathways; the first, aimed at the demonstration of modular detector design and the second, at the exploration of new signal readout methods. This two-pronged approach has provided a hig...

The Noble-Abel Stiffened-Gas equation of state

Science.gov (United States)

Le Métayer, Olivier; Saurel, Richard

2016-04-01

Hyperbolic two-phase flow models have shown excellent ability for the resolution of a wide range of applications ranging from interfacial flows to fluid mixtures with several velocities. These models account for waves propagation (acoustic and convective) and consist in hyperbolic systems of partial differential equations. In this context, each phase is compressible and needs an appropriate convex equation of state (EOS). The EOS must be simple enough for intensive computations as well as boundary conditions treatment. It must also be accurate, this being challenging with respect to simplicity. In the present approach, each fluid is governed by a novel EOS named "Noble Abel stiffened gas," this formulation being a significant improvement of the popular "Stiffened Gas (SG)" EOS. It is a combination of the so-called "Noble-Abel" and "stiffened gas" equations of state that adds repulsive effects to the SG formulation. The determination of the various thermodynamic functions and associated coefficients is the aim of this article. We first use thermodynamic considerations to determine the different state functions such as the specific internal energy, enthalpy, and entropy. Then we propose to determine the associated coefficients for a liquid in the presence of its vapor. The EOS parameters are determined from experimental saturation curves. Some examples of liquid-vapor fluids are examined and associated parameters are computed with the help of the present method. Comparisons between analytical and experimental saturation curves show very good agreement for wide ranges of temperature for both liquid and vapor.

Determination of sodium bis(2-ethylhexylsulfosuccinate (AOT surfactant with liquid chromatography: Comparative study of evaporative light scattering detector, ultraviolet detector and conductivity detector

Directory of Open Access Journals (Sweden)

Ho Ryul Ryu

2010-03-01

Full Text Available This work presents comparison of performance of ultraviolet (UV detector, conductivity detector (CD and evaporative light scattering detector (ELSD in terms of quantitative analysis of AOT (sodium bis(2-ethylhexylsulfosuccinate using liquid chromatography. The employed chromatographic condition, including an acetonitrile/water (45:55, v/v isocratic eluent system, is suitable for the three different detectors, and the figures of merits obtained by building up calibration plots are compared. The sensitivities of the detectors are in the order of ELSD ≈ CD >> UV detector. The linear range for quantification of AOT depends on the type of detector: the lower limits are in the order of UV detector (207 ㎍ mL-1 < CD (310 ㎍ mL-1 << ELSD (930 ㎍ mL-1, while the upper limits are 3720 ㎍ mL-1 for all the detectors (the maximum concentration of injected standard solution. The detection limits are 155 ㎍ mL-1 for ELSD, 78 ㎍ mL-1 for UV detector and 13 ㎍ mL-1 for CD, respectively. The figures of merit for each detector could be a guideline in choosing a detector in quantization of AOT. Furthermore, application of the chromatographic method to two commercial products is demonstrated.

Development of membrane cryostats for large liquid argon neutrino detectors

CERN Document Server

Montanari, D; Gendotti, A; Geynisman, M; Hentschel, S; Loew, T; Mladenov, D; Montanari, C; Murphy, S; Nessi, M; Norris, B; Noto, F; Rubbia, A; Sharma, R; Smargianaki, D; Stewart, J; Vignoli, C; Wilson, P; Wu, S

2015-01-01

A new collaboration is being formed to develop a multi-kiloton Long-Baseline neutrino experiment that will be located at the Surf Underground Research Facility (SURF) in Lead, SD. In the present design, the detector will be located inside cryostats filled with 68,400 ton of ultrapure liquid argon (less than 100 parts per trillion of oxygen equivalent contamination). To qualify the membrane technology for future very large-scale and underground implementations, a strong prototyping effort is ongoing: several smaller detectors of growing size with associated cryostats and cryogenic systems will be designed and built at Fermilab and CERN. They will take physics data and test different detector elements, filtration systems, design options and installation procedures. In addition, a 35 ton prototype is already operational at Fermilab and will take data with single-phase detector in early 2016. After the prototyping phase, the multi-kton detector will be constructed. After commissioning, it will detect and study ne...

Optical scattering lengths in large liquid-scintillator neutrino detectors

Energy Technology Data Exchange (ETDEWEB)

Wurm, M.; Feilitzsch, F. von; Goeger-Neff, M.; Hofmann, M.; Lewke, T.; Meindl, Q.; Moellenberg, R.; Oberauer, L.; Potzel, W.; Tippmann, M.; Todor, S.; Winter, J. [Physik-Department E15, Technische Universitaet Muenchen, James-Franck-Str., D-85748 Garching (Germany); Lachenmaier, T.; Traunsteiner, C. [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstr. 2, D-85748 Garching (Germany); Undagoitia, T. Marrodan [Physik-Department E15, Technische Universitaet Muenchen, James-Franck-Str., D-85748 Garching (Germany); Physik-Institut, Universitaet Zuerich, Winterthurstr. 189, CH-8057 Zuerich (Switzerland)

2010-05-15

For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.

Optical scattering lengths in large liquid-scintillator neutrino detectors.

Science.gov (United States)

Wurm, M; von Feilitzsch, F; Göger-Neff, M; Hofmann, M; Lachenmaier, T; Lewke, T; Marrodán Undagoitia, T; Meindl, Q; Möllenberg, R; Oberauer, L; Potzel, W; Tippmann, M; Todor, S; Traunsteiner, C; Winter, J

2010-05-01

For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.

Investigation on n/γ discrimination methods for liquid scintillator detector

International Nuclear Information System (INIS)

Li Kuinian; Li Yang; Zhang Mei; Zhang Zhongbing; Li Binkang; Zhang Xiaodong; Liu Jun; Zhang Xianpeng

2014-01-01

To obtain the n/γ discrimination ability of different digital pulse shape discrimination methods, four methods (rising time method, charge comparison method, pulse gradient analysis and frequency gradient analysis) in americium-beryllium mixed radiation fields were demonstrated. The signals from EJ-301 and BC501A scintillator detectors were digitized using oscilloscope. A comparison was taken among the four discrimination methods. The discrimination results of the four methods in liquid scintillator detectors show that the rising time method is the best and it provides a good choice in real-time n/γ discrimination system. (authors)

Defense by-products production and utilization program: noble metal recovery screening experiments

International Nuclear Information System (INIS)

Hazelton, R.F.; Jensen, G.A.; Raney, P.J.

1986-03-01

Isotopes of the platinum metals (rutheium, rhodium, and palladium) are produced during uranium fuel fission in nuclear reactors. The strategic values of these noble metals warrant considering their recovery from spent fuel should the spent fuel be processed after reactor discharge. A program to evaluate methods for ruthenium, rhodium, and palladium recovery from spent fuel reprocessing liquids was conducted at Pacific Northwest Laboratory (PNL). The purpose of the work reported in this docuent was to evaluate several recovery processes revealed in the patent and technical literature. Beaker-scale screening tests were initiated for three potential recovery processes: precipitation during sugar denitration of nitric acid reprocessing solutions after plutonium-uranium solvent extraction, adsorption using nobe metal selective chelates on active carbon, and reduction forming solid noble metal deposits on an amine-borane reductive resin. Simulated reprocessing plant solutions representing typical nitric acid liquids from defense (PUREX) or commercial fuel reprocessing facilities were formulated and used for evaluation of the three processes. 9 refs., 3 figs., 9 tabs

Development of cryogenic installations for large liquid argon neutrino detectors

CERN Document Server

Adamowski, M; Geynisman, M; Hentschel, S; Montanari, D; Nessi, M; Norris, B

2015-01-01

A proposal for a very large liquid argon (68,000 kg) based neutrino detector is being studied. To validate the design principles and the detector technology, and to gain experience in the development of the cryostats and the cryogenic systems needed for such large experiments, several smaller scale installations will be developed and implemented, at Fermilab and CERN. The cryogenic systems for these installations will be developed, constructed, installed and commissioned by an international engineering team. These installations shall bring the required cooling power under specific conditions to the experiments for the initial cool-down and the long term operation, and shall also guarantee the correct distribution of the cooling power within the cryostats to ensure a homogeneous temperature distribution within the cryostat itself. The cryogenic systems shall also include gaseous and liquid phase argon purification devices to be used to reach and maintain the very stringent purity requirements needed for these...

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air.

Science.gov (United States)

Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

2016-04-08

Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m²/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

Operation of CdZnTe Semiconductor Detectors in Liquid Scintillator for the COBRA Experiment

International Nuclear Information System (INIS)

Oldorf, Christian

2015-08-01

COBRA, the Cadmium-Zinc-Telluride O-neutrino double-Beta Research Apparatus, is an experiment aiming for the measurement of the neutrinoless double beta decay with several isotopes, in particular 116 Cd, 106 Cd and 130 Te. A highly granular large scale experiment with about 400 kg of CdZnTe semiconductor detectors is currently under development. To provide evidence for the neutrinoless double beta decay of 116 Cd, a background rate in the order of 10 -3 counts/keV/kg/a is needed to achieve the required half-life sensitivity of at least 2 . 10 26 years. To reach this target, the detectors have to be operated in a highly pure environment, shielded from external radiation. Liquid scintillator is a promising candidate as a circum fluent replacement for the currently used lacquer. Next to the function as highly pure passivation material, liquid scintillator also acts as a neutron shield and active veto for external gammas. Within this thesis, the design, construction and assembly of a test set-up is described. The operation of four CdZnTe detectors after several years of storage in liquid scintillator is demonstrated. Next to extensive material compatibility tests prior to the assembly, the commissioning of the set-up and the characterization of the detectors are shown. Finally, results concerning the background reduction capability of liquid scintillator and the detection of cosmic muons are presented and compared to a Monte Carlo simulation.

Noble Gases in Lakes and Ground Waters

OpenAIRE

Kipfer, Rolf; Aeschbach-Hertig, Werner; Peeters, Frank; Stute, Marvin

2002-01-01

In contrast to most other fields of noble gas geochemistry that mostly regard atmospheric noble gases as 'contamination,' air-derived noble gases make up the far largest and hence most important contribution to the noble gas abundance in meteoric waters, such as lakes and ground waters. Atmospheric noble gases enter the meteoric water cycle by gas partitioning during air / water exchange with the atmosphere. In lakes and oceans noble gases are exchanged with the free atmosphere at the surface...

Selective noble gases monitoring

International Nuclear Information System (INIS)

Janecka, S.; Jancik, O.; Kapisovsky, V.; Kubik, I.; Sevecka, S.

1995-01-01

The monitoring of leak releases from ventilation stack of NPP requires a system by several orders more sensitive then currently used radiometer Kalina, designed to cover the range up to a design-based accident. To reach this goal a noble gases monitor with a germanium detector (MPVG) has been developed. It enables nuclide selective monitoring of current value of volume activity of particular nuclides in ventilation stack and daily releases of noble gases (balancing). MPVG can be viewed as a system build of three levels of subsystem: measuring level; control level; presentation level. Measuring level consists of gamma-spectroscopy system and operational parameters monitoring unit (flow rate, temperature, humidity). Control level provides communication between presentation and measuring level, acquisition of operational parameters and power supply. The presentation level of MPVG enables: 1) the measured data storage in predetermined time intervals; 2) the presentation of measured and evaluated values of radiation characteristics. The monitored radionuclides - default set: argon-41, krypton-85m, krypton-87, krypton-88, krypton-89, xenon-131m, xenon-133, xenon-133m, xenon-135, xenon-135m, xenon-137 and xenon-138. The values of volume activities observed at maximum releases have been approximately ten times higher. In that case in balancing some other nuclides exceed corresponding detection limits: 88 Kr(67; 22) Bq/m 3 ; 85m Kr(17; 7) Bq/m 3 ; 135m Xe(7.1; 0.5) Bq/m 3 ; 138 Xe(5.9; 0.9) Bq/m 3 . (J.K.)

Selective noble gases monitoring

Energy Technology Data Exchange (ETDEWEB)

Janecka, S; Jancik, O; Kapisovsky, V; Kubik, I; Sevecka, S [Nuclear Power Plants Research Institute, a.s., Trnava (Slovakia)

1996-12-31

The monitoring of leak releases from ventilation stack of NPP requires a system by several orders more sensitive then currently used radiometer Kalina, designed to cover the range up to a design-based accident. To reach this goal a noble gases monitor with a germanium detector (MPVG) has been developed. It enables nuclide selective monitoring of current value of volume activity of particular nuclides in ventilation stack and daily releases of noble gases (balancing). MPVG can be viewed as a system build of three levels of subsystem: measuring level; control level; presentation level. Measuring level consists of gamma-spectroscopy system and operational parameters monitoring unit (flow rate, temperature, humidity). Control level provides communication between presentation and measuring level, acquisition of operational parameters and power supply. The presentation level of MPVG enables: 1) the measured data storage in predetermined time intervals; 2) the presentation of measured and evaluated values of radiation characteristics. The monitored radionuclides - default set: argon-41, krypton-85m, krypton-87, krypton-88, krypton-89, xenon-131m, xenon-133, xenon-133m, xenon-135, xenon-135m, xenon-137 and xenon-138. The values of volume activities observed at maximum releases have been approximately ten times higher. In that case in balancing some other nuclides exceed corresponding detection limits: {sup 88}Kr(67; 22) Bq/m{sup 3}; {sup 85m}Kr(17; 7) Bq/m{sup 3}; {sup 135m}Xe(7.1; 0.5) Bq/m{sup 3}; {sup 138}Xe(5.9; 0.9) Bq/m{sup 3}. (J.K.).

Performance of a liquid argon preshower detector integrated with an Accordion calorimeter

International Nuclear Information System (INIS)

Aubert, B.; Bazan, A.; Beaugiraud, B.; Colas, J.; Leflour, T.; Maire, M.; Vialle, J.P.; Wingerter-Seez, I.; Zolnierowski, Y.P.; Gordon, H.A.; Radeka, V.; Rahm, D.; Stephani, D.; Bulgakov, N.; Chevalley, J.L.; Fabjan, C.W.; Fournier, D.; Gildemeister, O.; Jenni, P.; Nessi, M.; Nessi-Tedaldi, F.; Pepe, M.; Richter, W.; Soderqvist, J.; Vuillemin, V.; Baze, J.M.; Gosset, L.; Lavocat, P.; Lottin, J.P.; Mansoulie, B.; Meyer, J.P.; Renardy, J.F.; Teiger, J.; Zaccone, H.; Battistoni, G.; Camin, D.V.; Cavalli, D.; Costa, G.; Cravero, A.; Ferrari, A.; Gianotti, F.; Mandelli, L.; Mazzanti, M.; Perini, L.; Pessina, G.; Sciamanna, M.; Auge, E.; Chase, R.; Chollet, J.C.; La Taille, C. de; Fayard, L.; Hrisoho, A.; Jean, P.; Le Meur, G.; Merkel, B.; Noppe, J.M.; Parrour, G.; Petroff, P.; Repellin, J.P.; Schaffer, A.; Seguin, N.; Unal, G.; Fuglesang, C.; Lefebvre, M.

1993-01-01

A prototype liquid argon preshower detector with a strip granularity of 2.5 mm has been tested at the CERN SPS in front of a liquid argon Accordion calorimeter. For charged tracks a signal-to-noise ratio of 9.4 and a space resolution of 340 μm were measured; the rejection power against overlapping photons produced in the decay of 50 GeV π 0 's is larger than 3; the precision on the electromagnetic shower direction, determined together with the calorimeter, is better than 7 mrad above 40 GeV; the calorimeter performance behind the preshower (≅4X 0 ) is fully preserved. These results make such a detector attractive for future operation at the CERN Large Hadron Collider. (orig.)

The ICARUS T600 Liquid Argon Detector Operation in the Underground Gran Sasso Laboratory

CERN Document Server

Vignoli, C

2014-01-01

The ICARUS T600 Module is the largest liquid argon detector (760 t LAr mass) ever realized to study neutrino oscill ations and matter stability in the deep underground Gran Sasso Laboratory. One of t he key elements for the detector performance is the liquid argon purity: residual electronegative compounds in argon have to be kept as low as 0.1 part s per billion all over the detector run. The T600 Module design was finalized by the ICARUS Collaboration after years of R&D studies that brought to the viable and scalable industrial solutions necessary for sized experiments with severe safety prescriptions for the underground operation . We present the T600 Module successful commissioning and the 3-years efficient, stable and continuous operation with extraordinary LAr purity, high performance and zero dead time data taking . This result demonstrates for the first time the feasibility of activation and long-term run in safe conditions of sized cryogenic detectors even in a confined underground location and r...

Noble Gas Leak Detector for Use in the SNS Neutron Electric Dipole Moment Experiment

Science.gov (United States)

Barrow, Chad; Huffman, Paul; Leung, Kent; Korobkina, Ekaterina; White, Christian; nEDM Collaboration Collaboration

2017-09-01

Common practice for leak-checking high vacuum systems uses helium as the probing gas. However, helium may permeate some materials at room temperature, making leak characterization difficult. The experiment to find a permanent electric dipole moment of the neutron (nEDM), to be conducted at Oak Ridge National Laboratories, will employ a large volume of liquid helium housed by such a helium-permeable composite material. It is desirable to construct a leak detector that can employ alternative test gases. The purpose of this experiment is to create a leak detector that can quantify the argon gas flux in a high vacuum environment and interpret this flux as a leak-rate. This apparatus will be used to check the nEDM volumes for leaks at room temperature before cooling down to cryogenic temperatures. Our leak detector uses a residual gas analyzer and a vacuum pumping station to characterize the gas present in an evacuated volume. The introduction of argon gas into the system is interpreted as a leak-rate into the volume. The device has been calibrated with NIST certified calibrated leaks and the machine's sensitivity has been calculated using background gas analysis. As a result of the device construction and software programming, we are able to leak-check composite and polyamide volumes This work was supported in part by the US Department of Energy under Grant No. DE-FG02-97ER41042.

Method to separate fission noble gases from gaseous wastes of a reprocessing plant for nuclear fuel material

International Nuclear Information System (INIS)

Schnez, H.

1977-01-01

In order to avoid the high cost expenditure in the separation of fission noble gases from waste gas of the head end, the following economical method is suggested: The fission noble gases released in the solvent - after grinding and burn-up of the nuclear fuel elements and dissolving in HNO 3 - are purified in a known method and collected in an equalizing tank. From here, the fission noble gas quantity necessary as washing gas is recycled into the solvent, so that a part of the fission noble gas quantity flows in a circuit. The quantity of fission noble gas not required for the above is separated from the circuit, compressed and put into a storage container from where it can be put into gas flashs or be recycled in the gas circuit where necessary. Furthermore, the method involves that to separate krypton, the filtered fission noble gas is compressed, cooled and rectified, whereby the krypton mixture taken from the rectification column is stored under high pressure and the gas part containing xenon, occuring as liquid, is at least partly fed back to the solvent. (HPH) [de

40Ar/39Ar dating of Quaternary volcanic ashes by multi-collection noble gas mass spectrometry: protocols, precision and intercalibration

DEFF Research Database (Denmark)

Storey, Michael; Rivera, Tiffany; Flude, Stephanie

) higher mass resolution allows hydrocarbon interferences to be pseudo resolved for the different argon isotopes; and (iv) multi-collection, allowing more data to be gathered in a fixed time in comparison with single-collector peak-switching measurements. We evaluate (i) protocols for detector inter......The recent availability of commercial high-resolution, multi-collector, noble gas mass spectrometers equipped with ion-counting electron multipliers provides new opportunities for improved precision in 40Ar/39Ar dating. This is particularly true for single crystal dating of Quaternary aged samples...... where potassium-bearing phenocrysts may contain relatively small amounts of radiogenic 40Ar. In 2005, the Quaternary Dating Laboratory, Roskilde University, installed a Nu-Instruments multi-collector Noblesse noble gas mass spectrometer, which is configured with a Faraday detector and three ion...

Cryogenics for Particle Accelerators and Detectors

CERN Document Server

Lebrun, P; Vandoni, Giovanna; Wagner, U

2002-01-01

Cryogenics has become a key ancillary technology of particle accelerators and detectors, contributing to their sustained development over the last fifty years. Conversely, this development has produced new challenges and markets for cryogenics, resulting in a fruitful symbiotic relation which materialized in significant technology transfer and technical progress. This began with the use of liquid hydrogen and deuterium in the targets and bubble chambers of the 1950s, 1960s and 1970s. It developed more recently with increasing amounts of liquefied noble gases - mainly argon, but also krypton and even today xenon - in calorimeters. In parallel with these applications, the availability of practical type II superconductors from the early 1960s triggered the use of superconductivity in large spectrometer magnets - mostly driven by considerations of energy savings - and the corresponding development of helium cryogenics. It is however the generalized application of superconductivity in particle accelerators - RF ac...

Deposition and characterization of noble metal onto surfaces of 304l stainless steel

International Nuclear Information System (INIS)

Contreras R, A.; Arganis J, C. R.; Aguilar T, J. A.; Medina A, A. L.

2010-10-01

Noble metal chemical addition (NMCA) plus hydrogen water chemistry is an industry-wide accepted approach for potential intergranular stress corrosion cracking mitigation of BWR internals components. NMCA is a method of applying noble metal onto BWR internals surfaces using reactor water as the transport medium that causes the deposition of noble metal from the liquid onto surfaces. In this work different platinum concentration solutions were deposited onto pre-oxidized surfaces of 304l steel at 180 C during 48 hr in an autoclave. In order to simulate the zinc water conditions, deposits of Zn and Pt-Zn were also carried out. The solutions used to obtain the deposits were: sodium hexahydroxyplatinate (IV), zinc nitrate hydrate and zinc oxide. The deposits obtained were characterized by scanning electron microscopy and X-ray diffraction. Finally, the electrochemical corrosion potential of pre-oxidized samples with Pt deposit were obtained and compared with the electrochemical corrosion potential of only pre-oxidized samples. (Author)

Noble gases in common rocks and their bearing on noble gas occurrences in the hydrological cycle

International Nuclear Information System (INIS)

Mazor, E.

1978-10-01

The comparison of the noble gases contents in different rocks and in thermal and cold water sources in the French Massif Central was aimed to define the amounts and nature of noble gases contributed by country rocks as opposed to atmospheric noble gases brought in by recharged water. No difference in the noble gas contents was found between waters coming in igneous rocks to those issuing in sedimentary rocks. In both, significant variations in the contents of atmospheric and radiogenic noble gases were found. Radiogenic helium has been found to reveal a positive correlation to the contents of atmospheric Ne, Ar, Kr. This indicates water recharge into the deep part of the systems, mixing with radiogenic He and Ar flushed from igneous and sedimentary rocks and subsequent partial gas loss. Loss of gas is evident from the observed low noble gas contents. These losses have been accompanied by a reversed retention pattern of Ne, Ar, Xc. This reversed retention pattern cannot be an artifact of sampling as well as cannot result by partial steam loss. A similar interpretation for the observed noble gas depletions that agrees with the fact that the observed fractionation patterns are not ''normal'' is given by deuterium and oxygen-18. The stable isotope data seem to exclude partial steam losses

Alphas and surface backgrounds in liquid argon dark matter detectors

Science.gov (United States)

Stanford, Christopher J.

Current observations from astrophysics indicate the presence of dark matter, an invisible form of matter that makes up a large part of the mass of the universe. One of the leading theories for dark matter is that it is made up of Weakly Interacting Massive Particles (WIMPs). One of the ways we try to discover WIMPs is by directly detecting their interaction with regular matter. This can be done using a scintillator such as liquid argon, which gives off light when a particle interacts with it. Liquid argon (LAr) is a favorable means of detecting WIMPs because it has an inherent property that enables a technique called pulse-shape discrimination (PSD). PSD can distinguish a WIMP signal from the constant background of electromagnetic signals from other sources, like gamma rays. However, there are other background signals that PSD is not as capable of rejecting, such as those caused by alpha decays on the interior surfaces of the detector. Radioactive elements that undergo alpha decay are introduced to detector surfaces during construction by radon gas that is naturally present in the air, as well as other means. When these surface isotopes undergo alpha decay, they can produce WIMP-like signals in the detector. We present here two LAr experiments. The first (RaDOSE) discovered a property of an organic compound that led to a technique for rejecting surface alpha decays in LAr detectors with high efficiency. The second (DarkSide-50) is a dark matter experiment operated at LNGS in Italy and is the work of an international collaboration. A detailed look is given into alpha decays and surface backgrounds present in the detector, and projections are made of alpha-related backgrounds for 500 live days of data. The technique developed with RaDOSE is applied to DarkSide-50 to determine its effectiveness in practice. It is projected to suppress the surface background in DarkSide-50 by more than a factor of 1000.

Spillage detector for liquid chromatography systems

Science.gov (United States)

Jarvis, M. J.; Fulton, D. S. (Inventor)

1986-01-01

A spillage detector device for use in conjunction with fractionation of liquid chromatography systems which includes a spillage recieving enclosure beneath the fractionation area is described. A sensing device having a plurality of electrodes of alternating polarity is mounted within the spillage recieving enclosure. Detection circuitry, responsive to conductivity between electrodes, is operatively connected to the sensing device. The detection circuitry feeds into the output circuitry. The output circuit has relaying and switching circuitry directed to a solenoid, an alarm system and a pump. The solenoid is connected to the pliable conduit of the chromatography system. The alarm system comprises an audio alarm and a visual signal. A 115-volt power system interconnected with the pump, the solenoid, the sensing device, and the detection and output circuitry.

Performance and stability tests of bare high purity germanium detectors in liquid argon for the GERDA experiment

Energy Technology Data Exchange (ETDEWEB)

Barnabe Heider, Marik

2009-05-27

GERDA will search for neutrinoless double beta decay of {sup 76}Ge by using a novel approach of bare germanium detectors in liquid argon (LAr). Enriched germanium detectors from the previous Heidelberg-Moscow and IGEX experiments have been reprocessed and will be deployed in GERDA Phase-I. At the center of this thesis project is the study of the performance of bare germanium detectors in cryogenic liquids. Identical detector performance as in vacuum cryostats (2.2 keV FWHM at 1.3 MeV) was achieved in cryogenic liquids with a new low-mass detector assembly and contacts. One major result is the discovery of a radiation induced leakage current (LC) increase when operating bare detectors with standard passivation layers in LAr. Charge collection and build-up on the passivation layer were identified as the origin of the LC increase. It was found that diodes without passivation do not exhibit this feature. Three month-long stable operation in LAr at {proportional_to} 5 pA LC under periodic gamma irradiation demonstrated the suitability of the modi ed detector design. Based on these results, all Phase-I detectors were reprocessed without passivation layer and subsequently successfully characterized in LAr in the GERDA underground Detector Laboratory. The mass loss during the reprocessing was {proportional_to}300 g out of 17.9 kg and the exposure above ground {proportional_to} 5 days. This results in a negligible cosmogenic background increase of {proportional_to} 5.10{sup -4} cts/(keV.kg.y) at {sup 76}Ge Q{sub {beta}}{sub {beta}} for {sup 60}Co and {sup 68}Ge. (orig.)

COOLC, Ne-213 Liquid Scintillation Detector Neutron Spectra Unfolding

International Nuclear Information System (INIS)

1971-01-01

1 - Nature of physical problem solved: COOLC is designed to calculate a neutron energy spectrum from a pulse-height spectrum produced by a detector system using the liquid scintillator NE-213. 2 - Method of solution: The program estimates the counts which would be observed in an ideal detector system having a response which is specified by the user. The solution implicitly takes into account the non-negativity of the desired neutron spectrum. The solution is obtained by finding a nearly optimal combination of slices through the spectrometer response functions such that their sum approximates the response of a channel of the ideal analyzer, and then uses the coefficients so determined to obtain an estimate of the desired neutron spectrum. 3 - Restrictions on the complexity of the problem: There are none noted

Study of sample-detector assemblies for application to in-situ measurement of radioactivity in liquid effluents

International Nuclear Information System (INIS)

Pendharkar, K.A.; Narayanan Kutty, K.; Krishnamony, S.

1991-01-01

This paper describes the experimental investigations carried out on four different types of sample-detector assemblies with a view to determining their detection limits and relative merits for application to in-situ measurement of radioactivity in liquid effluents. The four systems studied were: (1) gamma detection using 11 cm x 8 cm NaI (Tl) scintillation detector inserted in the cavity of a specially designed stainless steel chamber of capacity 15 liters, (2) gamma detection using a metal-walled G.M. counter in a similar manner, (3) beta detection using twin thin-walled G.M. counters immersed in liquid, and (4) end window G.M. counter positioned above the liquid surface in a shallow tray. The design features of an in-line monitor employing a 11 cm x 8 cm NaI (Tl) detector used for the routine monitoring of beta gamma activity concentrations in the low level effluents of the Tarapur Fuel Processing Plant are described. (author). 1 tab

Pulse shape analysis of enriched BEGe detectors in vacuum cryostat and liquid argon

Energy Technology Data Exchange (ETDEWEB)

Wagner, Victoria [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Collaboration: GERDA-Collaboration

2013-07-01

The Gerda experiment searches for the lepton number violating neutrinoless double beta (0νββ) decay of {sup 76}Ge. Germanium diodes of BEGe type (Canberra, Belgium) made from isotopically modified material have been procured for Phase II of Gerda. They will improve the sensitivity of the experiment by additional target mass, improved energy resolution and enhanced pulse shape discrimination (PSD) against background events. The PSD efficiencies of the new enriched BEGe detectors were studied in vacuum cryostats as part of the characterization campaign at the HADES underground laboratory. For a deeper understanding of the pulse shape performance of the enriched BEGe detectors, detailed {sup 241}Am surface scans were performed. Unexpectedly high position-dependence of the pulse shape parameter Amplitude-over-Energy was found for some of the detectors. With further investigation this effect was traced to surface charge effects specific to the operational configuration of the detectors inside the vacuum cryostats. The standard behavior is restored when they are operated in liquid argon in the configuration intended for Gerda Phase II. Finally, five of the enriched BEGe diodes were installed in the Gerda liquid argon cryostat prior to the full upgrade. They show a good performance and are able to reject efficiently multi-site-events as well as β- and α-particles.

A large liquid scintillator detector for a long baseline neutrino oscillation experiment

International Nuclear Information System (INIS)

Border, P.; Cushman, P.; Heller, K.; Maxam, D.; Nelson, J.K.; Ruddick, K.; Rusack, R.; Schwienhorst, R.; Berg, T.; Chase, T.; Hansen, M.; Bower, C.; Hatcher, R.; Heinz, R.; Miller, L.; Mufson, S.

2001-01-01

We present the concept and design of a liquid scintillator detector for a long-baseline neutrino oscillation experiment. Neutrinos interact in 2.5 cm thick steel plates alternating with 2.0 cm thick planes of liquid scintillator. The scintillator is contained in multicell PVC extrusions containing individual 2 cmx3 cm cells up to 8 m long. Readout of the scintillation light is via wavelength-shifting fibers which transport light to pixellated photodetectors at one end of the cells

Line emissions from sonoluminescence in aqueous solutions of halide salts without noble gases

Energy Technology Data Exchange (ETDEWEB)

Liang, Jinfu, E-mail: liang.shi2007@163.com [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001 (China); Chen, Weizhong, E-mail: wzchen@nju.edu.cn [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); Zhou, Chao; Cui, Weicheng; Chen, Zhan [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China)

2015-02-20

Line emissions of trivalent terbium (Tb{sup 3+}) ion were observed from single-bubble sonoluminescence (SL) in an aqueous solution of terbium chloride (TbCl{sub 3}) that contained no noble gas. In addition, sodium (Na) lines were observed in multi-bubble SL in aqueous solutions of various halide salts that contained no noble gas. These observations show that the halide ions, such as Cl{sup −}, Br{sup −}, and I{sup −}, help for line emissions as the noble gases. The intensity of a line emission depends on both the chemical species produced by cavitation bubbles and the temperature of SL bubble that responds to the driving ultrasound pressure. With the increase of driving pressure, some line emissions attached to the continuous spectrum may become increasingly clear, while other line emissions gradually become indistinct. - Highlights: • Line emissions of Tb(III) ions were observed without the presence of noble gases. • The halide ions help to generate a line emission during sonoluminescence. • The intensity of a line emission mainly depends on the bubble's temperature. • The definition of a line emission is related to the temperature of caviation bubble and the kind of host liquid.

Occulting Light Concentrators in Liquid Scintillator Neutrino Detectors

Science.gov (United States)

Buizza Avanzini, Margherita; Cabrera, Anatael; Dusini, Stefano; Grassi, Marco; He, Miao; Wu, Wenjie

2017-09-01

The experimental efforts characterizing the era of precision neutrino physics revolve around collecting high-statistics neutrino samples and attaining an excellent energy and position resolution. Next generation liquid-based neutrino detectors, such as JUNO, HyperKamiokande, etc, share the use of a large target mass, and the need of pushing light collection to the edge for maximal calorimetric information. Achieving high light collection implies considerable costs, especially when considering detector masses of several kt. A traditional strategy to maximize the effective photo-coverage with the minimum number of PMTs relies on Light Concentrators (LC), such as Winston Cones. In this paper, the authors introduce a novel concept called Occulting Light Concentrators (OLC), whereby a traditional LC gets tailored to a conventional PMT, by taking into account its single-photoelectron collection efficiency profile and thus occulting the worst performing portion of the photocathode. Thus, the OLC shape optimization takes into account not only the optical interface of the PMT, but also the maximization of the PMT detection performances. The light collection uniformity across the detector is another advantage of the OLC system. By considering the case of JUNO, we will show OLC capabilities in terms of light collection and energy resolution.

Chromatographic separation of radioactive noble gases from xenon

Science.gov (United States)

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

2018-01-01

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

A liquid scintillator detector for the solar neutrino

Energy Technology Data Exchange (ETDEWEB)

Ranucci, G [Lab. Nazionali del Gran Sasso, Assergi (Italy) Massachusetts Inst. of Technology, Cambridge, MA (United States) Joint Inst. for Nuclear Research, Dubna (USSR) Technical Univ. of Munich, Garching (Germany) Physics Dept., Univ. Genova (Italy) INFN, Genova (Italy) Univ. Hawaii, Honolulu, HI (United States) CCR Euratom, Ispra (Italy) Physics Dept., Univ. Milano (Italy) INFN, Milano (Italy) AT and T Bell Lab., Murray Hill, NJ (United States) Physics Dept., Univ. Pavia (Italy) INFN, Pavia (Italy) Physics Dept., Univ. Perugia (Italy) INFN, Perugia (Italy) Drexel Univ., Philadelphia, PA (United States) Charles Univ., Prague (Czechoslovakia) Czech Technical Univ., Prague (Czechoslovakia); Borex Collaboration

1992-05-01

Results of the three solar neutrino experiments presently running strongly suggest new neutrino physics scenarios to explain the discrepancy between the expected and measured neutrino flux. New experiments are needed to decide among the several theoretical explanations for this that has become known as the solar neutrino problem. This paper describes the unique features of the proposed low energy solar neutrino detector Borexino, that fully exploiting the powerful handless of liquid scintillation spectroscopy on large scale, will probe emerging suggestions on scenarios invoking neutrino mass mixing and magnetic moment. (orig.).

Large underground, liquid based detectors for astro-particle physics in Europe scientific case and prospects

CERN Document Server

Autiero, D; Badertscher, A; Bezrukov, L; Bouchez, J; Bueno, A; Busto, J; Campagne, J -E; Cavata, C; De Bellefon, A; Dumarchez, J; Ebert, J; Enqvist, T; Ereditato, A; Von Feilitzsch, F; Perez, P Fileviez; Goger-Neff, M; Gninenko, S; Gruber, W; Hagner, C; Hess, M; Hochmuth, K A; Kisiel, J; Knecht, L; Kreslo, I; Kudryavtsev, V A; Kuusiniemi, P; Lachenmaier, T; Laffranchi, M; Lefièvre, B; Lightfoot, P K; Lindner, M; Maalampi, J; Maltoni, M; Marchionni, A; Undagoitia, T Marrodan; Meregaglia, A; Messina, M; Mezzetto, M; Mirizzi, A; Mosca, L; Moser, U; Müller, A; Natterer, G; Oberauer, L; Otiougova, P; Patzak, T; Peltoniemi, J; Potzel, W; Pistillo, C; Raffelt, G G; Rondio, E; Roos, M; Rossi, B; Rubbia, André; Savvinov, N; Schwetz, T; Sobczyk, J; Spooner, N J C; Stefan, D; Tonazzo, A; Trzaska, W; Ulbricht, J; Volpe, C; Winter, J; Wurm, M; Zalewska-Bak, A; Zimmermann, R

2007-01-01

This document reports on a series of experimental and theoretical studies conducted to assess the astro-particle physics potential of three future large-scale particle detectors proposed in Europe as next generation underground observatories. The proposed apparatus employ three different and, to some extent, complementary detection techniques: GLACIER (liquid Argon TPC), LENA (liquid scintillator) and MEMPHYS (\\WC), based on the use of large mass of liquids as active detection media. The results of these studies are presented along with a critical discussion of the performance attainable by the three proposed approaches coupled to existing or planned underground laboratories, in relation to open and outstanding physics issues such as the search for matter instability, the detection of astrophysical- and geo-neutrinos and to the possible use of these detectors in future high-intensity neutrino beams.

A liquid-nitrogen monitor for lithium-drifted germanium detectors

International Nuclear Information System (INIS)

Andeweg, A.H.

1977-11-01

An instrument has been developed that makes use of a load cell to monitor the liquid nitrogen in the Dewar flask of a lithium-drifted germaniun detector. The contents are recorded on a chart recorder, and an alarm is sounded when the previously set content has been reached. A signal switches off the high-voltage power supply 30 minutes after the alarm is triggered. The calibration of the load-cell monitor is described in an appendix [af

Dark matter sensitivity of multi-ton liquid xenon detectors

International Nuclear Information System (INIS)

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

2015-01-01

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

The research program of the Liquid Scintillation Detector (LSD) in the Mont Blanc Laboratory

Science.gov (United States)

Dadykin, V. L.; Yakushev, V. F.; Korchagin, P. V.; Korchagin, V. B.; Malgin, A. S.; Ryassny, F. G.; Ryazhskaya, O. G.; Talochkin, V. P.; Zatsepin, G. T.; Badino, G.

1985-01-01

A massive (90 tons) liquid scintillation detector (LSD) has been running since October 1984 in the Mont Blanc Laboratory at a depth of 5,200 hg/sq cm of standard rock. The research program of the experiment covers a variety of topics in particle physics and astrophysics. The performance of the detector, the main fields of research are presented and the preliminary results are discussed.

Radiation detectors

International Nuclear Information System (INIS)

2013-01-01

This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

ZnO nanoneedle/H2O solid-liquid heterojunction-based self-powered ultraviolet detector

Science.gov (United States)

2013-01-01

ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. High photosensitivity, excellent spectral selectivity, and fast photoresponse at zero bias are observed in this UV detector. The self-powered behavior can be well explained by the formation of a space charge layer near the interface of the solid-liquid heterojunction, which results in a built-in potential and makes the solid-liquid heterojunction work in photovoltaic mode. PMID:24103153

Electrical resistivity of noble-metal alloys: Roles of pseudopotential refinements

International Nuclear Information System (INIS)

Mujibar Rahman, S.M.

1983-08-01

The electrical resistivity of liquid noble-metal alloys i.e. CuAu and AgAu is calculated as a function of concentration. The calculations employ transition-metal-pseudopotentials that include nonlocal effects, hybridization and corrections due to orthogonalization hole and use the hard-sphere structure factors; the optimal values of the hard-sphere diameters are being determined by variational calculations. The calculated resistivities are comparable to the experimental values and to the available theoretical results. (author)

Noble gas magnetic resonator

Science.gov (United States)

Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

2014-04-15

Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

Absorption of scintillation light in a 100l liquid xenon γ-ray detector and expected detector performance

International Nuclear Information System (INIS)

Baldini, A.; Bemporad, C.; Cei, F.; Doke, T.; Grassi, M.; Grebenuk, A.A.; Grigoriev, D.N.; Haruyama, T.; Kasami, K.; Kikuchi, J.; Maki, A.; Mashimo, T.; Mihara, S.; Mitsuhashi, T.; Mori, T.; Nicolo, D.; Nishiguchi, H.; Ootani, W.; Ozone, K.; Papa, A.; Pazzi, R.; Ritt, S.; Sawada, R.; Sergiampietri, F.; Signorelli, G.; Suzuki, S.; Terasawa, K.; Yamashita, M.; Yamashita, S.; Yoshimura, T.; Yuri, Yu.

2005-01-01

An 800l liquid xenon scintillation γ-ray detector is being developed for the MEG experiment which will search for μ + ->e + γdecay at the Paul Scherrer Institut. Absorption of scintillation light of xenon by impurities might possibly limit the performance of such a detector. We used a 100l prototype with an active volume of 372x372x496mm 3 to study the scintillation light absorption. We have developed a method to evaluate the light absorption, separately from elastic scattering of light, by measuring cosmic rays and α sources. By using a suitable purification technique, an absorption length longer than 100cm has been achieved. The effects of the light absorption on the energy resolution are estimated by Monte Carlo simulation

Noble gases solubility in water

International Nuclear Information System (INIS)

Crovetto, Rosa; Fernandez Prini, Roberto.

1980-07-01

The available experimental data of solubility of noble gases in water for temperatures smaller than 330 0 C have been critically surveyed. Due to the unique structure of the solvent, the solubility of noble gases in water decreases with temperature passing through a temperature of minimum solubility which is different for each gas, and then increases at higher temperatures. As aresult of the analysis of the experimental data and of the features of the solute-solvent interaction, a generalized equation is proposed which enables thecalculation of Henry's coefficient at different temperatures for all noble gases. (author) [es

Noble gases in nuclear medicine

International Nuclear Information System (INIS)

Calderon, M.; Burdine, J.A.

1973-01-01

Radioactive noble gases have made a significant contribution to diagnostic nuclear medicine. In the area of regional assessment of pulmonary function, 133 Xe has had its greatest clinical impact. Following a breath of 133 Xe gas, pulmonary ventilation can be measured using a scintillation camera or other appropriate radiation detector. If 133 Xe dissolved in saline is injected intravenously, both pulmonary capillary perfusion and ventilation can be measured since 90 percent of the highly insoluble xenon escapes into the alveoli during the first passage through the lungs. Radionuclide pulmonary function tests provide the first qualitative means of assessing lung ventilation and blood flow on a regional basis, and have recently been extended to include quantification of various parameters of lung function by means of a small computer interfaced to the scintillation camera. 133 Xe is also used in the measurement of organ blood flow following injection into a vessel leading into an organ such as the brain, heart kidneys, or muscles

Direct coupling of a liquid chromatograph to a continuous flow hydrogen nuclear magnetic resonance detector for analysis of petroleum and synthetic fuels

International Nuclear Information System (INIS)

Haw, J.F.; Glass, T.E.; Hausler, D.W.; Motell, E.; Dorn, H.C.

1980-01-01

Initial results obtained for a flow 1 H nuclear magnetic resonance (NMR) detector directly coupled to a liquid chromatography unit are described. Results achieved for a model mixture and several jet fuel samples are discussed. Chromatographic separation of alkanes, alkylbenzenes, and substituted naphthalenes present in the jet fuel samples are easily identified with the 1 H NMR detector. Results with our present flow 1 H NMR insert indicate that 5-Hz linewidths are readily obtainable for typical chromatographic flow rates. The limitations and advantages of this liquid chromatography detector are compared with more commonly employed detectors (e.g., refractive index detectors). 11 figures

Recovery and use of fission product noble metals

International Nuclear Information System (INIS)

Jensen, G.A.; Rohmann, C.A.; Perrigo, L.D.

1980-06-01

Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value

Developing Detectors for Scintillation Light in Liquid Argon for DUNE

Energy Technology Data Exchange (ETDEWEB)

Howard, Bruce [Fermilab

2016-12-22

The Deep Underground Neutrino experiment will conduct a broad program of physics research by studying a beam of neutrinos from Fermilab, atmospheric neutrinos, neutrinos from potential supernovae, and potential nucleon decay events. In pursuit of these studies, the experiment will deploy four 10kt fiducial mass liquid argon time projection chambers underground in Lead, South Dakota. Liquid argon time projection chambers allow high-resolution tracking and energy measurements. A precise timing signal is needed to provide the necessary time stamp to localize events in the drift direction. As liquid argon is a natural scintillator, a photon detection system will be deployed to provide such a signal, especially for non-beam events. In the baseline design for the single-phase time projection chamber, the detectors are contained within the anode plane assemblies. The design of two prototypes utilizing wavelength shifters and light guides are presented, and aspects of the research and development program are discussed.

Realization of the low background neutrino detector Double Chooz. From the development of a high-purity liquid and gas handling concept to first neutrino data

Energy Technology Data Exchange (ETDEWEB)

Pfahler, Patrick

2012-12-17

Neutrino physics is one of the most vivid fields in particle physics. Within this field, neutrino oscillations are of special interest as they allow to determine driving oscillation parameters, which are collected as mixing angles in the leptonic mixing matrix. The exact knowledge of these parameters is the main key for the investigation of new physics beyond the currently known Standard Model of particle physics. The Double Chooz experiment is one of three reactor disappearance experiments currently taking data, which recently succeeded to discover a non-zero value for the last neutrino mixing angle {Theta}{sub 13}. As successor of the CHOOZ experiment, Double Chooz will use two detectors with improved design, each of them now composed of four concentrically nested detector vessels each filled with different detector liquid. The integrity of this multi-layered structure and the quality of the used detector liquids are essential for the success of the experiment. Within this frame, the here presented work describes the production of two detector liquids, the filling and handling of the Double Chooz far detector and the installation of all necessary hardware components therefore. In order to meet the strict requirements existing for the detector liquids, all components were individually selected in an extensive material selection process at TUM, which compared samples from different companies for their key properties: density, transparency, light yield and radio purity. Based on these measurements, the composition of muon veto scintillator and buffer liquid were determined. For the production of the detector liquids, a simple surface building close to the far detector site was upgraded into a large-scale storage and mixing facility, which allowed to separately, mix, handle and store 90 m{sup 3} of muon veto scintillator and 110 m{sup 3} of buffer liquid. For the muon veto scintillator, a master-solution composed of 4800 l LAB, 180 kg PPO and 1.8 kg of bis/MSB was

Realization of the low background neutrino detector Double Chooz. From the development of a high-purity liquid and gas handling concept to first neutrino data

International Nuclear Information System (INIS)

Pfahler, Patrick

2012-01-01

Neutrino physics is one of the most vivid fields in particle physics. Within this field, neutrino oscillations are of special interest as they allow to determine driving oscillation parameters, which are collected as mixing angles in the leptonic mixing matrix. The exact knowledge of these parameters is the main key for the investigation of new physics beyond the currently known Standard Model of particle physics. The Double Chooz experiment is one of three reactor disappearance experiments currently taking data, which recently succeeded to discover a non-zero value for the last neutrino mixing angle Θ 13 . As successor of the CHOOZ experiment, Double Chooz will use two detectors with improved design, each of them now composed of four concentrically nested detector vessels each filled with different detector liquid. The integrity of this multi-layered structure and the quality of the used detector liquids are essential for the success of the experiment. Within this frame, the here presented work describes the production of two detector liquids, the filling and handling of the Double Chooz far detector and the installation of all necessary hardware components therefore. In order to meet the strict requirements existing for the detector liquids, all components were individually selected in an extensive material selection process at TUM, which compared samples from different companies for their key properties: density, transparency, light yield and radio purity. Based on these measurements, the composition of muon veto scintillator and buffer liquid were determined. For the production of the detector liquids, a simple surface building close to the far detector site was upgraded into a large-scale storage and mixing facility, which allowed to separately, mix, handle and store 90 m 3 of muon veto scintillator and 110 m 3 of buffer liquid. For the muon veto scintillator, a master-solution composed of 4800 l LAB, 180 kg PPO and 1.8 kg of bis/MSB was produced and

Scintillation trigger system of the liquid argon neutrino detector

International Nuclear Information System (INIS)

Belikov, S.V.; Gurzhiev, S.N.; Gutnikov, Yu.E.; Denisov, A.G.; Kochetkov, V.I.; Matveev, M.Yu.; Mel'nikov, E.A.; Usachev, A.P.

1994-01-01

This paper presents the organization of the Scintillation Trigger System (STS) for the Liquid Argon Neutrino Detector of the Tagged Neutrino Facility. STS is aimed at the effective registration of the needed neutrino interaction type and production of a fast trigger signal with high time resolution. The fast analysis system of analog signal from the trigger scintillation planes for rejection of the trigger signals from background processes is described. Real scintillation trigger planes characteristics obtained on the basis of the presented data acquisition system are shown. 10 refs., 12 figs., 3 tabs

A cryogenic monitor system for the Liquid Argon Calorimeter in the SLD detector

International Nuclear Information System (INIS)

Fox, M.J.; Fox, J.D.

1988-10-01

This paper describes the monitoring electronics system design for the Liquid Argon Calorimeter (LAC) portion of the SLD detector. This system measures temperatures and liquid levels inside the LAC cryostat and transfers the results over a fiber-optic serial link to an external monitoring computer. System requirements, unique design constraints, and detailed analog, digital and software designs are presented. Fault tolerance and the requirement for a single design to work in several different operating environments are discussed. 4 refs., 3 figs., 1 tab

Monitoring gross alpha and beta activity in liquids by using ZnS(Ag) scintillation detectors

Energy Technology Data Exchange (ETDEWEB)

Stevanato, L.; Cester, D.; Filippi, D.; Lunardon, M.; Mistura, G.; Moretto, S.; Viesti, G. [Department of Physics and Astronomy ' Galileo Galilei' , University of Padova, (Italy); Badocco, D.; Pastore, P.; Romanini, F. [Department of Chemical Sciences, University of Padova, (Italy)

2015-07-01

In this work the possibility of monitoring gross alpha and beta activity in liquids using EJ-444 was investigated. Specific tests were carried out to determine the change of the detector properties in water tests. Possible protecting coating is also proposed and tested. Alpha/beta real-time monitoring in liquids is a goal of the EU project TAWARA{sub R}TM. (authors)

Comparison of the tensile bond strength of high-noble, noble, and base metal alloys bonded to enamel.

Science.gov (United States)

Sen, D; Nayir, E; Pamuk, S

2000-11-01

Although the bond strengths of various resin composite luting materials have been reported in the literature, the evaluation of these systems with various cast alloys of different compositions has not been completely clarified. To evaluate the tensile bond strength of sandblasted high-noble, noble, and base metal alloys bonded to etched enamel by 2 different bonding agents of different chemical composition: Panavia-Ex (BIS-GMA) and Super-Bond (4-META acrylic). Flat enamel surfaces were prepared on buccal surfaces of 60 extracted noncarious human incisors. Teeth were divided into 3 groups of 20 each. Twenty circular disks of 5 mm diameter were prepared for casting for each group. Group I was cast with a high-noble, group II with a noble, and group III with a base metal alloy. The surfaces of the disks were sandblasted with 250 microm Al(2)O(3). Ten disks of each group were bonded to exposed enamel surfaces with Super-Bond and 10 disks with Panavia-Ex as recommended by the manufacturer. The tensile bond strength was measured with an Instron universal testing machine with a crosshead speed of 0.5 mm/min until failure occurred. Two-way ANOVA was used to evaluate the results. The differences in bond strengths of Super-Bond and Panavia-Ex with different alloys were not significant. The highest bond strengths were obtained in base metal alloys, followed by noble and high-noble alloys. These results were significant. Panavia-Ex and Super-Bond exhibited comparable tensile bond strengths. For both luting agents, the highest bond strengths were achieved with base metal alloys and the lowest with high-noble alloys.

Gaseous photomultipliers for the readout of scintillators and detection Cherenkov radiation

International Nuclear Information System (INIS)

Peskov, V.; Borovik-Romanov, A.

1993-11-01

The latest achievements in the development of gaseous detectors for registering UV and visible photons are described. Possible modifications of their design for some particular applications such as the readout of crystal scintillators. noble liquids, fibers and for large area Cherenkov detectors are discussed

Charged particle identification with the liquid Xenon calorimeter of the CMD-3 detector

International Nuclear Information System (INIS)

Ivanov, V.L.; Fedotovich, G.V.; Anisenkov, A.V.; Grebenuk, A.A.; Mikhailov, K.Yu.; Kozyrev, A.A.; Shebalin, V.E.; Ruban, A.A.; Bashtovoy, N.S.

2017-01-01

This paper describes a procedure of particle identification with the liquid Xenon calorimeter of the CMD-3 detector currently being developed. The procedure uses the boosted decision tree classification method with specific energy losses of charged particles in the liquid Xenon calorimeter as input variables. The efficiency of the procedure is illustrated by an example of the measurement of the cross section of the process e + e − → K + K − in the center-of-mass energy range from 1.8 to 2.0 GeV.

Low energy neutrino astrophysics with the large liquid-scintillator detector LENA

International Nuclear Information System (INIS)

Wurm, M.; Feilitzsch, F. von; Goeger-Neff, M.; Undagoitia, T. Marrodan; Oberauer, L.; Potzel, W.; Winter, J.

2007-01-01

The large-volume liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) will cover a broad field of physics. Apart from the detection of terrestrial and artificial neutrinos, and the search for proton decay, important contributions can be made to the astrophysics of stars by high-precision spectroscopy of low-energetic solar neutrinos and by the observation of neutrinos emitted by a galactic supernova. Moreover, the detection of the diffuse supernova neutrino background in LENA will offer the opportunity of studying both supernova core-collapse models and the supernova rate on cosmological timescales (z e events in an almost background-free energy window from ∼10 to 25 MeV. The search for such rare low-energetic events takes advantage of the high energy resolution and excellent background rejection possible in the LENA detector

Muonium formation in noble gases and noble gas mixtures

International Nuclear Information System (INIS)

Stambaugh, R.D.; Casperson, D.E.; Crane, T.W.; Hughes, V.W.; Kaspar, H.F.; Souder, P.; Thompson, P.A.; Orth, H.; zu Putlitz, G.; Denison, A.B.

1974-01-01

An experiment is reported to study the behavior of positive muons stopped in He, Ne, and Xe in order to provide a more complete understanding of muonium formation in the noble gases. Free muon and muonium precession are plotted. (U.S.)

Measuring the noble metal and iodine composition of extracted noble metal phase from spent nuclear fuel using instrumental neutron activation analysis

International Nuclear Information System (INIS)

Palomares, R.I.; Dayman, K.J.; Landsberger, S.; Biegalski, S.R.; Soderquist, C.Z.; Casella, A.J.; Brady Raap, M.C.; Schwantes, J.M.

2015-01-01

Masses of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis. Nuclide presence is predicted using fission yield analysis, and radionuclides are identified and the masses quantified using neutron activation analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO 2 fuel dissolved in nitric acid and UO 2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared. - Highlights: • The noble metal phase was chemically extracted from spent nuclear fuel and analyzed non-destructively. • Noble metal phase nuclides and long-lived iodine were identified and quantified using neutron activation analysis. • Activation to shorter-lived radionuclides allowed rapid analysis of long-lived fission products in spent fuel using gamma spectrometry

Pulse-shape discrimination in NE213 liquid scintillator detectors

International Nuclear Information System (INIS)

Cavallaro, M.; Tropea, S.; Agodi, C.; Assié, M.; Azaiez, F.; Boiano, C.; Bondì, M.; Cappuzzello, F.; Carbone, D.; De Napoli, M.; Séréville, N. de; Foti, A.; Linares, R.; Nicolosi, D.; Scarpaci, J.A.

2013-01-01

The 16-channel fast stretcher BaFPro module, originally developed for processing signals of Barium Fluoride scintillators, has been modified to make a high performing analog pulse-shape analysis of signals from the NE213 liquid scintillators of the EDEN neutron detector array. The module produces two Gaussian signals, whose amplitudes are proportional to the height of the fast component of the output light and to the total energy deposited into the scintillator, respectively. An in-beam test has been performed at INFN-LNS (Italy) demonstrating a low detection threshold, a good pulse-shape discrimination even at low energies and a wide dynamic range for the measurement of the neutrons energy.

The CENNS-10 liquid argon detector to measure CEvNS at the Spallation Neutron Source

Science.gov (United States)

Tayloe, R.

2018-04-01

The COHERENT collaboration is deploying a suite of low-energy detectors in a low-background corridor of the ORNL Spallation Neutron Source (SNS) to measure coherent elastic neutrino-nucleus scattering (CEvNS) on an array of nuclear targets employing different detector technologies. A measurement of CEvNS on different nuclei will test the N2-dependence of the CEvNS cross section and further the physics reach of the COHERENT effort. The first step of this program has been realized recently with the observation of CEvNS in a 14.6 kg CsI detector. Operation and deployment of Ge and NaI detectors are also underway. A 22 kg, single-phase, liquid argon detector (CENNS-10) started data-taking in Dec. 2016 and will provide results on CEvNS from a lighter nucleus. Initial results indicate that light output, pulse-shape discrimination, and background suppression are sufficient for a measurement of CEvNS on argon.

Characterization of liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system

Energy Technology Data Exchange (ETDEWEB)

Lombigit, L., E-mail: lojius@nm.gov.my; Yussup, N., E-mail: nolida@nm.gov.my; Ibrahim, Maslina Mohd; Rahman, Nur Aira Abd; Rawi, M. Z. M. [Instrumentation Group, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

2015-04-29

A digital n/γ pulse shape discrimination (PSD) system is currently under development at Instrumentation and Automation Centre, Malaysian Nuclear Agency. This system aims at simultaneous detection of fast neutron and gamma ray in mixed radiations environment. This work reports the system characterization performed on the liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system. The characterization involves measurement of electron light output from the BC-501A detector and energy channels calibration of the pulse height spectra acquired with DPSD system using set of photon reference sources. The main goal of this experiment is to calibrate the ADC channel of our DPSD system, characterized the BC-501 detector and find the position of Compton edge which later could be used as threshold for the n/γ PSD experiment. The detector resolution however is worse as compared to other published data but it is expected as our detector has a smaller active volume.

Characterization of liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system

International Nuclear Information System (INIS)

Lombigit, L.; Yussup, N.; Ibrahim, Maslina Mohd; Rahman, Nur Aira Abd; Rawi, M. Z. M.

2015-01-01

A digital n/γ pulse shape discrimination (PSD) system is currently under development at Instrumentation and Automation Centre, Malaysian Nuclear Agency. This system aims at simultaneous detection of fast neutron and gamma ray in mixed radiations environment. This work reports the system characterization performed on the liquid scintillation detector (BC-501A) and digital pulse shape discrimination (DPSD) system. The characterization involves measurement of electron light output from the BC-501A detector and energy channels calibration of the pulse height spectra acquired with DPSD system using set of photon reference sources. The main goal of this experiment is to calibrate the ADC channel of our DPSD system, characterized the BC-501 detector and find the position of Compton edge which later could be used as threshold for the n/γ PSD experiment. The detector resolution however is worse as compared to other published data but it is expected as our detector has a smaller active volume

Hadron and electron response of uranium/liquid argon calorimeter modules for the D0 detector

International Nuclear Information System (INIS)

Abolins, M.; Astur, R.; Edmunds, D.; Linnemann, J.T.; Mooney, P.; Owen, D.P.; Pi, B.; Pope, B.G.; Weerts, H.; Ahn, S.C.; Demarteau, M.; Forden, G.E.; Good, M.L.; Grannis, P.D.; Guida, J.A.; Heuring, T.; Marx, M.; McCarthy, R.; Ng, K.K.; Paterno, M.; Schamberger, R.D.; Timko, M.; Aronson, S.H.; Featherly, J.; Gibbard, B.G.; Gordon, H.A.; Guida, J.M.; Guryn, W.; Kahn, S.; Protopopescu, S.; Yamin, P.; Bartlett, J.F.; Bross, A.D.; Christenson, J.H.; Cooper, W.E.; Fisk, H.E.; Haggerty, H.; Ito, A.S.; Johnson, M.E.; Jonckheere, A.M.; Merritt, K.W.; Raja, R.; Smith, R.P.; Treadwell, E.; Blazey, G.C.; Borders, J.; Draper, P.; Durston, S.; Ferbel, T.; Hirosky, R.; Kewley, D.; Libonate, S.; Lobkowicz, F.; Franzini, P.; Tuts, P.M.; Gerecht, J.; Kononenko, W.; Selove, W.; Wang, H.; Hadley, N.J.; Hagopian, S.; Linn, S.; Piekarz, H.; Wahl, H.D.; Yousseff, S.; Klopfenstein, C.; Madaras, R.J.; Spadafora, A.L.; Stevenson, M.L.; Wenzel, W.A.; Kotcher, J.; Kourlas, J.; Nemethy, P.; Nesic, D.; Sculli, J.; Martin, H.J.; Zieminski, A.; Roberts, K.; Wimpenny, S.J.; White, A.P.; Womersley, W.J.

1989-01-01

We present the results of tests on two types of uranium/liquid calorimeter modules, one electromagnetic and one hadronic, constructed for the DO detector at the Fermilab Tevatron Collider. For electrons and hardons with energies between 10 and 150 GeV, we present measurements of energy resolution, linearity of response, electromagnetic to hadronic response ratio (e/π), and longitudinal hadronic shower development. We have also investigated the effects of adding small amounts of methane to the liquid argon. (orig.)

Advanced far infrared blocked impurity band detectors based on germanium liquid phase epitaxy

Energy Technology Data Exchange (ETDEWEB)

Olsen, Christopher Sean [Univ. of California, Berkeley, CA (United States)

1998-05-01

This research has shown that epilayers with residual impurity concentrations of 5 x 10¹³ cm^-3 can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as long as pure enough solvents are available. The detectors have responded at proper wavelengths when reversed biased even though the response did not quite reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm^-1 with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.

The Future of Low Temperature Germanium as Dark Matter Detectors

CERN Multimedia

CERN. Geneva

2009-01-01

The Weakly Interactive Massive Particles (WIMPs) represent one of the most attractive candidates for the dark matter in the universe. With the combination of experiments attempting to detect WIMP scattering in the laboratory, of searches for their annihilation in the cosmos and of their potential production at the LHC, the next five years promise to be transformative. I will review the role played so far by low temperature germanium detectors in the direct detection of WIMPs. Because of its high signal to noise ratio, the simultaneous measurement of athermal phonons and ionization is so far the only demonstrated approach with zero-background. I will argue that this technology can be extrapolated to a target mass of the order of a tonne at reasonable cost and can keep playing a leading role, complementary to noble liquid technologies. I will describe in particular GEODM, the proposed Germanium Observatory for Dark Matter at the US Deep Underground Science and Engineering Laboratory (DUSEL).

Noble Gas signatures of Enhanced Oil Recovery

Science.gov (United States)

Barry, P. H.; Kulongoski, J. T.; Tyne, R. L.; Hillegonds, D.; Byrne, D. J.; Landon, M. K.; Ballentine, C. J.

2017-12-01

Noble gases are powerful tracers of fluids from various oil and gas production activities in hydrocarbon reservoirs and nearby groundwater. Non-radiogenic noble gases are introduced into undisturbed oil and natural gas reservoirs through exchange with formation waters [1-3]. Reservoirs with extensive hydraulic fracturing, injection for enhanced oil recovery (EOR), and/or waste disposal also show evidence for a component of noble gases introduced from air [4]. Isotopic and elemental ratios of noble gases can be used to 1) assess the migration history of the injected and formation fluids, and 2) determine the extent of exchange between multiphase fluids in different reservoirs. We present noble gas isotope and abundance data from casing, separator and injectate gases of the Lost Hills and Fruitvale oil fields in the San Joaquin basin, California. Samples were collected as part of the California State Water Resource Control Board's Oil and Gas Regional Groundwater Monitoring Program. Lost Hills (n=7) and Fruitvale (n=2) gases are geochemically distinct and duplicate samples are highly reproducible. Lost Hills casing gas samples were collected from areas where EOR and hydraulic fracturing has occurred in the past several years, and from areas where EOR is absent. The Fruitvale samples were collected from a re-injection port. All samples are radiogenic in their He isotopes, typical of a crustal environment, and show enrichments in heavy noble gases, resulting from preferential adsorption on sediments. Fruitvale samples reflect air-like surface conditions, with higher air-derived noble gas concentrations. Lost Hills gases show a gradation from pristine crustal signatures - indicative of closed-system exchange with formation fluids - to strongly air-contaminated signatures in the EOR region. Pristine samples can be used to determine the extent of hydrocarbon exchange with fluids, whereas samples with excess air can be used to quantify the extent of EOR. Determining noble

A Monte-Carlo code for neutron efficiency calculations for large volume Gd-loaded liquid scintillation detectors

Energy Technology Data Exchange (ETDEWEB)

Trzcinski, A.; Zwieglinski, B. [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Lynen, U. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Pochodzalla, J. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

1998-10-01

This paper reports on a Monte-Carlo program, MSX, developed to evaluate the performance of large-volume, Gd-loaded liquid scintillation detectors used in neutron multiplicity measurements. The results of simulations are presented for the detector intended to count neutrons emitted by the excited target residue in coincidence with the charged products of the projectile fragmentation following relativistic heavy-ion collisions. The latter products could be detected with the ALADIN magnetic spectrometer at GSI-Darmstadt. (orig.) 61 refs.

Noble magnetic barriers in the ASDEX UG tokamak

Science.gov (United States)

Ali, Halima; Punjabi, Alkesh; Vazquez, Justin

2010-02-01

The second-order perturbation method of creating invariant tori inside chaos in Hamiltonian systems (Ali, H.; Punjabi, A. Plasma Phys. Contr. F. 2007, 49, 1565-1582) is applied to the axially symmetric divertor experiment upgrade (ASDEX UG) tokamak to build noble irrational magnetic barriers inside chaos created by resonant magnetic perturbations (m, n)=(3, 2)+(4, 3), with m and n the poloidal and toroidal mode numbers of the Fourier expansion of the magnetic perturbation. The radial dependence of the Fourier modes is ignored. The modes are considered to be locked and have the same amplitude δ. A symplectic mathematical mapping in magnetic coordinates is used to integrate magnetic field line trajectories in the ASDEX UG. Tori with noble irrational rotational transform are the last ones to be destroyed by perturbation in Hamiltonian systems. For this reason, noble irrational magnetic barriers are built inside chaos, and the strongest noble irrational barrier is identified. Three candidate locations for the strongest noble barrier in ASDEX UG are selected. All three candidate locations are chosen to be roughly midway between the resonant rational surfaces ψ32 and ψ43. ψ is the magnetic coordinate of the flux surface. The three candidate surfaces are the noble irrational surfaces close to the surface with q value that is a mediant of q=3/2 and 4/3, q value of the physical midpoint of the two resonant surfaces, and the q value of the surface where the islands of the two perturbing modes just overlap. These q values of the candidate surfaces are denoted by q MED, q MID, and q OVERLAP. The strongest noble barrier close to q MED has the continued fraction representation (CFR) [1;2,2,1∞] and exists for δ≤2.6599×10-4; the strongest noble barrier close to q MID has CFR [1;2,2,2,1∞] and exists for δ≤4.6311×10-4; and the strongest noble barrier close to q OVERLAP has CFR [1;2,2,6,2,1∞] and exists for δ≤1.367770×10-4. From these results, the strongest

Study of light detection and sensitivity for a ton-scale liquid xenon dark matter detector

International Nuclear Information System (INIS)

Wei, Y; Lin, Q; Xiao, X; Ni, K

2013-01-01

Ton-scale liquid xenon detectors operated in two-phase mode are proposed and being constructed recently to explore the favored parameter space for the Weakly Interacting Massive Particles (WIMPs) dark matter. To achieve a better light collection efficiency while limiting the number of electronics channels compared to the previous generation detectors, large-size photo-multiplier tubes (PMTs) such as the 3-inch-diameter R11410 from Hamamatsu are suggested to replace the 1-inch-square R8520 PMTs. In a two-phase xenon dark matter detector, two PMT arrays on the top and bottom are usually used. In this study, we compare the performance of two different ton-scale liquid xenon detector configurations with the same number of either R11410 (config.1) or R8520 (config.2) for the top PMT array, while both using R11410 PMTs for the bottom array. The self-shielding of liquid xenon suppresses the background from the PMTs and the dominant background is from the pp solar neutrinos in the central fiducial volume. The light collection efficiency for the primary scintillation light is largely affected by the xenon purity and the reflectivity of the reflectors. In the optimistic situation with a 10 m light absorption length and a 95% reflectivity, the light collection efficiency is 43%(34%) for config.1(config.2). In the conservative situation with a 2.5 m light absorption length and a 85% reflectivity, the value is only 18%(13%) for config.1(config.2). The difference between the two configurations is due to the larger PMT coverage on the top for config.1. The slightly different position resolutions for the two configurations have a negligible effect on the sensitivity. Based on the above considerations, we estimate the sensitivity reach of the two detector configurations. Both configurations can reach a sensitivity of 2 ∼ 3 × 10 −47 cm 2 for spin-independent WIMP-nucleon cross section for 100 GeV/c 2 WIMPs after two live-years of operation. The one with R8520 PMTs for the top

Advancing the use of noble gases in fluid inclusions of speleothems as a palaeoclimate proxy. Method and standardization

International Nuclear Information System (INIS)

Papp, L.; Palcsu, L.; Major, Z.; Svingor, E.

2010-01-01

Complete text of publication follows. Continental carbonates are essential archives of the past geological and climatological occurrences. Recently, fluid inclusions of carbonates have got into focus of palaeoclimate research. A new approach using temperature dependent gas solubilities might be a way that uses only physical laws, e.g. the Henry's law of solubility and gas partitioning models. The so-called noble gas temperature (NGT) can be calculated from the measured noble gas concentrations. This report describes how our first advancing steps towards obtaining NGT's from fluid inclusions and tiny water amounts have been preformed. To extract the water inclusions from the carbonate matrix, the most suitable treatment is to crush the carbonate under vacuum. The water released from the inclusions is then collected in a cold finger by freezing. The amount of the liberated water is measured via its vapour pressure in a certain volume (Fig. 1). The liberated dissolved noble gases which were in the fluid inclusions are separated by a cryo system, and then admitted into the static mode noble gas mass spectrometer sequentially. The calibration of the noble gas mass spectrometric measurements is performed by means of well known air aliquots. To check the reliability of the whole measurement procedure standard water samples have to be measured. As for standard samples, first we have prepared air equilibrated water (AEW) in conditioned circumstances. We fill copper capillaries with AEW. Having completed the copper capillary assemblage, the AEW is letting flow through the capillary (Fig. 2). The error of such a water determination is less than 1% in case of 1 μl of liquid water (Fig. 1) that allows us to determine accurate noble gas concentrations. The reproducibility of 40 Ar measurements is better than 0.6 %, while those of neon, krypton and xenon isotopes are 0.6-1.6 %, 0.9-2.2 % and 0.8-2.0 %, respectively. Theoretically, these precisions for noble gas concentrations

Noble-Metal Chalcogenide Nanotubes

Directory of Open Access Journals (Sweden)

Nourdine Zibouche

2014-10-01

Full Text Available We explore the stability and the electronic properties of hypothetical noble-metal chalcogenide nanotubes PtS2, PtSe2, PdS2 and PdSe2 by means of density functional theory calculations. Our findings show that the strain energy decreases inverse quadratically with the tube diameter, as is typical for other nanotubes. Moreover, the strain energy is independent of the tube chirality and converges towards the same value for large diameters. The band-structure calculations show that all noble-metal chalcogenide nanotubes are indirect band gap semiconductors. The corresponding band gaps increase with the nanotube diameter rapidly approaching the respective pristine 2D monolayer limit.

77 FR 70159 - Marble River, LLC v. Noble Clinton Windpark I, LLC, Noble Ellenburg Windpark, LLC, Noble...

Science.gov (United States)

2012-11-23

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL13-20-000] Marble River... Commission's (Commission) Rules of Practice and Procedure, Marble River, LLC (Marble River or Complainant.... (NYISO or Respondent), alleging that Noble failed to pay Marble River for headroom created by common...

The Induction of Noble Rot (Botrytis cinerea Infection during Postharvest Withering Changes the Metabolome of Grapevine Berries (Vitis vinifera L., cv. Garganega

Directory of Open Access Journals (Sweden)

Stefano Negri

2017-06-01

Full Text Available The natural or induced development of noble rot caused by the fungus Botrytis cinerea during the late stages of grapevine (Vitis vinifera L. berry ripening is used in some traditional viticulture areas to produce high-quality wines such as Sauternes and Tokaji. In this research, we wanted to verify if by changing the environmental conditions during post-harvest withering we could induce the noble rot development on harvested berries in order to positively change the wine produced from withered Garganega berries. Therefore, we exposed the berries to postharvest withering under normal or artificially humid conditions, the latter to induce noble rot. The presence of noble rot symptoms was associated with the development of B. cinerea in the berries maintained under humid conditions. The composition of infected and non-infected berries was investigated by untargeted metabolomics using liquid chromatography/mass spectrometry. We also explored the effects of the two withering methods on the abundance of volatile organic compounds in wine by yeast-inoculated micro-fermentation followed by targeted gas chromatography/mass spectrometry. These experiments revealed significant metabolic differences between berries withered under normal and humid conditions, indicating that noble rot affects berry metabolism and composition. As well as well-known botrytization markers, we detected two novel lipids that have not been observed before in berries infected with noble rot. Unraveling the specific metabolic profile of berries infected with noble rot may help to determine the compounds responsible for the organoleptic quality traits of botrytized Garganega wines.

Limits on the release of Rb isotopes from a zeolite based 83mKr calibration source for the XENON project

Czech Academy of Sciences Publication Activity Database

Hannen, V.M.; Aprile, E.; Baudis, L.; Beck, M.; Bokeloh, K.; Ferella, A.D.; Giboni, K.; Lang, R.F.; Lebeda, Ondřej; Ortjohann, H.W.; Schumann, M.; Špalek, Antonín; Vénos, Drahoslav; Weinheimer, C.

2011-01-01

Roč. 6, Oct. (2011), P10013/1-P10013/11 ISSN 1748-0221 R&D Project s: GA MŠk LC07050 Institutional research plan: CEZ:AV0Z10480505 Keywords : noble-liquid detectors * detector alignment * ionization two phase Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.869, year: 2011

Structural energetics of noble metals

International Nuclear Information System (INIS)

Mujibur Rahman, S.M.

1982-06-01

Structural energetics of the noble metals, namely Cu, Ag, and Au are investigated by employing a single-parameter pseudopotential. The calculations show that the lowest energy for all of these metals corresponds to FCC - their observed crystal structure. The one-electron contribution to the free energy is found to dominate the structural prediction for these metals. The present investigation strongly emphasizes that the effects due to band hybridization and core-core exchange play a significant role on the structural stability of the noble metals. (author)

Automated ion-exchange system for the radiochemical separation of the noble metals

International Nuclear Information System (INIS)

Parry, S.J.

1980-01-01

Ion-exchange separation is particularly suitable for mechanisation and automated ion exchange has been applied to the activation analysis of biological and environmental samples. In this work a system has been designed for experimental studies, which can be adapted for different modes of operation. The equipment is based on a large-volume sampler for the automatic presentation of 500 ml of liquid to a sampling probe. The sample is delivered to the ion-exchange column by means of a peristaltic pump. The purpose of this work was to automate a procedure for separating the noble metals from irradiated geological samples, for neutron-activation analysis. The process of digesting the rock sample is carried out manually in 30 min and is not suited to unattended operation. The volume of the resulting liquid sample may be 100 ml and so the manual separation step may take as long as 1.25 h per sample. The reason for automating this part of the procedure is to reduce the separation time for a group of five samples and consequently to improve the sensitivity of the analysis for radionuclides with short half-lives. This paper describes the automatic ion-exchange system and the ways in which it can be used. The mode of operation for the separation of the noble metals is given in detail. The reproducibility of the system has been assessed by repeated measurements on a standard reference matte. (author)

ArgonCube: a novel, fully-modular approach for the realization of large-mass liquid argon TPC neutrino detectors

CERN Document Server

Amsler, C; Asaadi, J; Auger, M; Barbato, F; Bay, F; Bishai, M; Bleiner, D; Borgschulte, A; Bremer, J; Cavus, E; Chen, H; De Geronimo, G; Ereditato, A; Fleming, B; Goldi, D; Hanni, R; Kose, U; Kreslo, I; La Mattina, F; Lanni, F; Lissauer, D; Luthi, M; Lutz, P; Marchionni, A; Mladenov, D; Nessi, M; Noto, F; Palamara, O; Raaf, J L; Radeka, V; Rudolph Von Rohr, Ch; Smargianaki, D; Soderberg, M; Strauss, Th; Weber, M; Yu, B; Zeller, G P; Zeyrek, M; CERN. Geneva. SPS and PS Experiments Committee; SPSC

2015-01-01

The Liquid Argon Time Projection Chamber is a prime candidate detector for future neutrino oscillation physics experiments, underground neutrino observatories and proton decay searches. A large international project based on this technology is currently being considered at the future LBNF facility in the United States on the very large mass scale of 40 kton. In this document, following the long standing R&D work conducted over the last years in several laboratories in Europe and in the United States, we intend to propose a novel Liquid Argon TPC approach based on a fully-modular, innovative design, the ArgonCube. The related R&D work will proceed along two main directions; one aimed at on the assessment of the proposed modular detector design, the other on the exploitation of new signal readout methods. Such a strategy will provide high performance while being cost-effective and robust at the same time. According to our plans, we will firstly realize a detector prototype hosted in a cryostat that is a...

Primordial Noble Gases from Earth's Core

Science.gov (United States)

Wang, K.; Lu, X.; Brodholt, J. P.

2016-12-01

Recent partitioning experiment suggests helium is more compatible in iron melt than in molten silicates at high pressures (> 10 GPa) (1), thus provide the possibility of the core as being the primordial noble gases warehouse that is responsible for the high primordial/radiogenic noble gas isotopic ratios observed in plume-related basalts. However, the possible transportation mechanism of the noble gases from the core to the overlying mantle is still ambiguous, understanding how this process would affect the noble gas isotopic characteristics of the mantle is critical to validate this core reservoir model. As diffusion is a dominant mass transport process that plays an important role in chemical exchange at the core-mantle boundary (CMB), we have determined the diffusion coefficients of helium, neon and argon in major lower mantle minerals, i.e. periclase (MgO), bridgemanite (MgSiO3-Pv) and post-perovskite (MgSiO3-PPv), by first-principles calculation based on density functional theory (DFT). As expected, the diffusion rate of helium is the fastest at the CMB, which is in the range of 3 × 10-10 to 1 × 10-8 m2/s. The neon diffusion is slightly slower, from 5 × 10-10 to 5 × 10-9 m2/s. Argon diffuses slowest at the rate from 1 × 10-10 to 2 × 10-10 m2/s. We have further simulated the evolution of noble gas isotopic ratios in the mantle near the CMB. Considering its close relationship with the mantle plumes and very likely to be the direct source of "hot-spot" basalts, we took a close investigation on the large low-shear-velocity provinces (LLSVPs). Under reasonable assumptions based on our diffusion parameters, the modelling results indicate that LLSVP is capable of generating all the noble gas isotope signals, e.g., 3He/4He = 55 Ra, 3He/22Ne = 3.1, 3He/36Ar = 0.82, 40Ar/36Ar = 9500, that are in good agreement with the observed values in "hot-spot" basalts (2). Therefore, this core-reservior hypothesis is a self-consistent model that can fits in multiple noble gas

Noble gas atoms as chemical impurities in silicon

International Nuclear Information System (INIS)

Tkachev, V.D.; Mudryi, A.V.; Minaev, N.S.

1984-01-01

The behaviour of noble gas atoms implanted in silicon is studied by the luminescence method. The energy position of Moessbauer-type luminescence bands with zero-phonon lines 1.0148, 1.0120, 1.0097, 1.0048 eV and others connected with implanted atoms of neon, helium, argon, krypton, respectively, indicates the formation of deep energy levels in the forbidden gap of silicon. Implantation of the noble gas isotopes confirms their participation in formation processes of the luminescence centers in silicon. The temperature range of existence and the symmetry of defects incorporating the noble gas atoms are found. It is noted that noble gas atoms form impurity complexes with deep energy levels and their behaviour in crystals does not differ from that of main doped or residual technological impurity atoms. (author)

Status of GENIUS-TF-II and TF-III-The long-term stability of naked detectors in liquid nitrogen

Energy Technology Data Exchange (ETDEWEB)

Klapdor-Kleingrothaus, H.V. [Max-Planck-Institut fuer Kernphysik, P.O. Box 10 39 80, D-69029 Heidelberg (Germany)]. E-mail: H.Klapdor@mpi-hd.mpg.de; Krivosheina, I.V. [Max-Planck-Institut fuer Kernphysik, P.O. Box 10 39 80, D-69029 Heidelberg (Germany)

2006-10-15

GENIUS-TF-II is a setup of six naked high purity Ge detectors (15kg) in liquid nitrogen in Gran Sasso. It has been installed in October, 2004-after the first four naked Ge detectors had been installed on May 5, 2003 (GENIUS-TF-I). The GENIUS-Test-Facility (GENIUS-TF) is the first and up to now only setup ever testing the novel technique aiming at extreme background reduction in search for rare decays in particular underground. The goal of GENIUS-TF was to test some key operational parameters of the full GENIUS project proposal in 1997 [H.V. Klapdor-Kleingrothaus, Int. J. Mod. Phys. A 13 (1998) 3953; H.V. Klapdor-Kleingrothaus, J. Hellmig, M. Hirsch, GENIUS-Proposal, 20 November 1997; J. Hellmig and H.V. Klapdor-Kleingrothaus, Z. Phys. A 359 ( 1997) 351 and nucl-ex/9801004; H.V. Klapdor-Kleingrothaus, M. Hirsch, Z. Phys. A 359 (1997) 361; H.V. Klapdor-Kleingrothaus, J. Hellmig, M. Hirsch, J. Phys. G 24 (1998) 483; H.V. Klapdor-Kleingrothaus, CERN Courier, November 1997, pp. 16-18]. Simultaneous physical goal is to search for the annual modulation of the Dark Matter signal [H.V. Klapdor-Kleingrothaus, et al., Nucl. Instr. and Meth. A 481 (2002) 149; C. Tomei, A. Dietz, I. Krivosheina, H.V. Klapdor-Kleingrothaus, Nucl. Instr. and Meth. 508 (2003) 343]. After operation of GENIUS-TF over three years with finally six naked Ge detectors (15kg) in liquid nitrogen in Gran Sasso we realize serious problems for realization of a full-size GENIUS-like experiment: (1) Background from Rn222 diffusing into the setup, on a level far beyond the expectation. (2) Limited long-term stability of naked detectors in liquid nitrogen as result of increasing leakage current. None of the six detectors is running after three years with the nominal leakage current. Three of the six detectors do not work any more at all. The results of our three years of investigation of the long-term stability may cast doubt on the possibility to perform full GENIUS-like projects.

Status of GENIUS-TF-II and TF-III-The long-term stability of naked detectors in liquid nitrogen

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Krivosheina, I.V.

2006-01-01

GENIUS-TF-II is a setup of six naked high purity Ge detectors (15kg) in liquid nitrogen in Gran Sasso. It has been installed in October, 2004-after the first four naked Ge detectors had been installed on May 5, 2003 (GENIUS-TF-I). The GENIUS-Test-Facility (GENIUS-TF) is the first and up to now only setup ever testing the novel technique aiming at extreme background reduction in search for rare decays in particular underground. The goal of GENIUS-TF was to test some key operational parameters of the full GENIUS project proposal in 1997 [H.V. Klapdor-Kleingrothaus, Int. J. Mod. Phys. A 13 (1998) 3953; H.V. Klapdor-Kleingrothaus, J. Hellmig, M. Hirsch, GENIUS-Proposal, 20 November 1997; J. Hellmig and H.V. Klapdor-Kleingrothaus, Z. Phys. A 359 ( 1997) 351 and nucl-ex/9801004; H.V. Klapdor-Kleingrothaus, M. Hirsch, Z. Phys. A 359 (1997) 361; H.V. Klapdor-Kleingrothaus, J. Hellmig, M. Hirsch, J. Phys. G 24 (1998) 483; H.V. Klapdor-Kleingrothaus, CERN Courier, November 1997, pp. 16-18]. Simultaneous physical goal is to search for the annual modulation of the Dark Matter signal [H.V. Klapdor-Kleingrothaus, et al., Nucl. Instr. and Meth. A 481 (2002) 149; C. Tomei, A. Dietz, I. Krivosheina, H.V. Klapdor-Kleingrothaus, Nucl. Instr. and Meth. 508 (2003) 343]. After operation of GENIUS-TF over three years with finally six naked Ge detectors (15kg) in liquid nitrogen in Gran Sasso we realize serious problems for realization of a full-size GENIUS-like experiment: (1) Background from Rn222 diffusing into the setup, on a level far beyond the expectation. (2) Limited long-term stability of naked detectors in liquid nitrogen as result of increasing leakage current. None of the six detectors is running after three years with the nominal leakage current. Three of the six detectors do not work any more at all. The results of our three years of investigation of the long-term stability may cast doubt on the possibility to perform full GENIUS-like projects

LArSoft: toolkit for simulation, reconstruction and analysis of liquid argon TPC neutrino detectors

Science.gov (United States)

Snider, E. L.; Petrillo, G.

2017-10-01

LArSoft is a set of detector-independent software tools for the simulation, reconstruction and analysis of data from liquid argon (LAr) neutrino experiments The common features of LAr time projection chambers (TPCs) enable sharing of algorithm code across detectors of very different size and configuration. LArSoft is currently used in production simulation and reconstruction by the ArgoNeuT, DUNE, LArlAT, MicroBooNE, and SBND experiments. The software suite offers a wide selection of algorithms and utilities, including those for associated photo-detectors and the handling of auxiliary detectors outside the TPCs. Available algorithms cover the full range of simulation and reconstruction, from raw waveforms to high-level reconstructed objects, event topologies and classification. The common code within LArSoft is contributed by adopting experiments, which also provide detector-specific geometry descriptions, and code for the treatment of electronic signals. LArSoft is also a collaboration of experiments, Fermilab and associated software projects which cooperate in setting requirements, priorities, and schedules. In this talk, we outline the general architecture of the software and the interaction with external libraries and detector-specific code. We also describe the dynamics of LArSoft software development between the contributing experiments, the projects supporting the software infrastructure LArSoft relies on, and the core LArSoft support project.

Noble Metal Nanoparticles for Biosensing Applications

Directory of Open Access Journals (Sweden)

Pedro V. Baptista

2012-02-01

Full Text Available In the last decade the use of nanomaterials has been having a great impact in biosensing. In particular, the unique properties of noble metal nanoparticles have allowed for the development of new biosensing platforms with enhanced capabilities in the specific detection of bioanalytes. Noble metal nanoparticles show unique physicochemical properties (such as ease of functionalization via simple chemistry and high surface-to-volume ratios that allied with their unique spectral and optical properties have prompted the development of a plethora of biosensing platforms. Additionally, they also provide an additional or enhanced layer of application for commonly used techniques, such as fluorescence, infrared and Raman spectroscopy. Herein we review the use of noble metal nanoparticles for biosensing strategies—from synthesis and functionalization to integration in molecular diagnostics platforms, with special focus on those that have made their way into the diagnostics laboratory.

Liquid ionization calorimetry: review and preview

International Nuclear Information System (INIS)

Fabjan, C.W.

1995-01-01

The experimental requirements at existing and planned accelerators, and new facilities for underground or space-borne experimentation have stimulated a wide-ranging R and D programme in liquid ionization calorimetry. Precision sampling calorimetry is approaching ''crystal'' energy resolution whilst their rate capabilities will be able to cope with the highest LHC luminosities. (Quasi)-homogeneous noble-liquid calorimeters are under construction or in the planning stage to address some of the most fundamental physics questions. (orig.)

Electrical resistivity of liquid noble metal alloys

International Nuclear Information System (INIS)

Anis Alam, M.; Tomak, M.

1983-08-01

Calculations of the dependence of the electrical resistivity in liquid Ag-Au, Cu-Ag, Cu-Au binary alloys on composition are reported. The structure of the binary alloy is described as a hard sphere system. A one-parameter local pseudopotential, which incorporates s-d hybridization effects phenomenologically, is employed in the resistivity calculation. A reasonable agreement with experimental trends is observed in cases where experimental information is available. (author)

Noble gases recycled into the mantle through cold subduction zones

Science.gov (United States)

Smye, Andrew J.; Jackson, Colin R. M.; Konrad-Schmolke, Matthias; Hesse, Marc A.; Parman, Steve W.; Shuster, David L.; Ballentine, Chris J.

2017-08-01

Subduction of hydrous and carbonated oceanic lithosphere replenishes the mantle volatile inventory. Substantial uncertainties exist on the magnitudes of the recycled volatile fluxes and it is unclear whether Earth surface reservoirs are undergoing net-loss or net-gain of H2O and CO2. Here, we use noble gases as tracers for deep volatile cycling. Specifically, we construct and apply a kinetic model to estimate the effect of subduction zone metamorphism on the elemental composition of noble gases in amphibole - a common constituent of altered oceanic crust. We show that progressive dehydration of the slab leads to the extraction of noble gases, linking noble gas recycling to H2O. Noble gases are strongly fractionated within hot subduction zones, whereas minimal fractionation occurs along colder subduction geotherms. In the context of our modelling, this implies that the mantle heavy noble gas inventory is dominated by the injection of noble gases through cold subduction zones. For cold subduction zones, we estimate a present-day bulk recycling efficiency, past the depth of amphibole breakdown, of 5-35% and 60-80% for 36Ar and H2O bound within oceanic crust, respectively. Given that hotter subduction dominates over geologic history, this result highlights the importance of cooler subduction zones in regassing the mantle and in affecting the modern volatile budget of Earth's interior.

The Borexino Detector

Science.gov (United States)

Montanari, David

2010-04-01

The Borexino detector is a large volume liquid scintillator detector for low energy neutrino spetroscopy currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. Main goal of the experiment is the real-time measurement of sub-MeV solar neutrinos, and particularly of the mono-energetic (862KeV) 7Be electron capture neutrinos, via neutrino-electron scattering in ultra-pure liquid scintillator. We report the description of the detector itself from its construction to the final current configuration. The initial requirements are first presented, then the strategy developed to achieve them: choice of materials and components, purification of the scintillator, cleaning, leak tightness, fluid handling. Every single point is analyzed, particularly the purification plants, that allowed reaching an ultra high pure scintillator and the fluid handling system, a large modular system connecting fluid receiving, purification and fluid delivery processes for every fluid involved. The different phases of the filling follow: from air to water to the final liquid scintillator, mainly focusing on the scintillator filling. The performances of the detector and the results are then presented.

Update on the use of dissolved oxygen addition to monitor the effectiveness of noble metal applications in external manifolds

International Nuclear Information System (INIS)

Varela, J.A.; Huie, H.H.; Seeman, R.A.; Bourne, C.M.; Odell, A.D.

2014-01-01

Electrochemical corrosion potential (ECP) measurements in a Mitigation Monitoring System (MMS) ECP manifold have historically been a primary indicator of the effectiveness of an On-Line NobleChem™ (OLNC) application, with the MMS ECP intended to measure the catalytic effect of noble metal deposited on the ECP manifold surface. In some plants ECP measurements made on untreated surfaces prior to an OLNC application were significantly lower than what would be expected for stainless steel under reactor bulk chemistry conditions. This is due to the consumption and depletion of bulk liquid dissolved oxygen (DO) in the lines supplying reactor water to these external ECP measurement locations. This phenomenon degrades the ability to use these external manifolds to confirm noble metal deposition. Previous papers have described how the injection of an oxygen-rich stream to the MMS supply stream (DO Addition) can be used to re-establish the capability of external ECP measurements to monitor the catalytic behavior of platinum deposited during an OLNC injection. This paper will provide an update of how this method is being successfully used in operating BWRs to monitor OLNC injections. The paper will outline the overall approach used to characterize the catalytic behavior of external ECP manifolds before and after the noble metal application and present plant data collected during DO Additions performed under various conditions. (author)

Liquid scintillators and liquefied rare gases for particle detectors. Background-determination in Double Chooz and scintillation properties of liquid argon

International Nuclear Information System (INIS)

Hofmann, Martin Alexander

2012-01-01

Evidence for physics beyond the well-established standard model of particle physics is found in the sector of neutrino physics, in particular in neutrino oscillations, and in experimental hints requiring the presence of Dark Matter. Neutrino oscillations demand the neutrinos to be massive and at least four additional parameters, three mixing angles and one phase, are introduced. A non-vanishing value for the third mixing angle, θ 13 , has only recently been found, amongst others by the reactor antineutrino disappearance experiment Double Chooz. This experiment detects anti ν e 's by means of the Inverse Beta Decay (IBD), which has a clear signature that can very effectively be discriminated from most of the background. However, some background still survives the selection cuts applied to the data, partly induced by radioactivity. In order to determine the amount of radioimpurities in the detector, germanium spectroscopy measurements and neutron activation analyses have been carried out for various parts of the Double Chooz far detector. A dedicated Monte-Carlo simulation was performed to obtain the singles event rate induced by the identified radioimpurities in the fiducial volume of Double Chooz. In the present thesis, parts from the outer detector systems, as well as components of the inner detector liquids were measured. In sum, a singles rate of less than 0.35 Hz above the antineutrino detection threshold of 0.7 MeV has been found. This is by far below the design goal of Double Chooz of ∝ 20 Hz. The analysis of bismuth-polonium (BiPo) coincidences in the first Double Chooz data allows to directly determine the number of decays from the U- and the Th-decay chain in the active detector parts. Assuming radioactive equilibrium, concentrations of (1.71±0.08).10 -14 (g)/(g) for uranium and (8.16±0.49).10 -14 (g)/(g) for thorium have been found, which are also well below the design goal of Double Chooz (2.10 -13 (g)/(g)). Both gamma spectroscopy measurements and

Liquid scintillators and liquefied rare gases for particle detectors. Background-determination in Double Chooz and scintillation properties of liquid argon

Energy Technology Data Exchange (ETDEWEB)

Hofmann, Martin Alexander

2012-11-27

Evidence for physics beyond the well-established standard model of particle physics is found in the sector of neutrino physics, in particular in neutrino oscillations, and in experimental hints requiring the presence of Dark Matter. Neutrino oscillations demand the neutrinos to be massive and at least four additional parameters, three mixing angles and one phase, are introduced. A non-vanishing value for the third mixing angle, {theta}{sub 13}, has only recently been found, amongst others by the reactor antineutrino disappearance experiment Double Chooz. This experiment detects anti {nu}{sub e}'s by means of the Inverse Beta Decay (IBD), which has a clear signature that can very effectively be discriminated from most of the background. However, some background still survives the selection cuts applied to the data, partly induced by radioactivity. In order to determine the amount of radioimpurities in the detector, germanium spectroscopy measurements and neutron activation analyses have been carried out for various parts of the Double Chooz far detector. A dedicated Monte-Carlo simulation was performed to obtain the singles event rate induced by the identified radioimpurities in the fiducial volume of Double Chooz. In the present thesis, parts from the outer detector systems, as well as components of the inner detector liquids were measured. In sum, a singles rate of less than 0.35 Hz above the antineutrino detection threshold of 0.7 MeV has been found. This is by far below the design goal of Double Chooz of {proportional_to} 20 Hz. The analysis of bismuth-polonium (BiPo) coincidences in the first Double Chooz data allows to directly determine the number of decays from the U- and the Th-decay chain in the active detector parts. Assuming radioactive equilibrium, concentrations of (1.71{+-}0.08).10{sup -14}(g)/(g) for uranium and (8.16{+-}0.49).10{sup -14}(g)/(g) for thorium have been found, which are also well below the design goal of Double Chooz (2.10{sup -13

Magneto-optical Kerr spectroscopy of noble metals

Science.gov (United States)

Uba, L.; Uba, S.; Antonov, V. N.

2017-12-01

Magneto-optical (MO) response of the noble metals Cu, Ag, and Au in the joint experimental and ab initio theoretical study is reported. The magneto-optical polar Kerr effect (MOKE) spectra of the noble-metal films were measured with the high sensitivity in the applied magnetic field of 1.5 T over the photon energy range 0.74-5.8 eV. Complete set of the optical conductivity tensor elements was determined precisely from the MOKE and the optical spectra measured at the same energy points. The importance of the off-diagonal intraband Drude-type transitions is demonstrated explicitly for each noble metal and found to be a substantial contribution to the observed spectra. It is shown that the first-principles calculations using the spin-polarized fully relativistic Dirac linear-muffin-tin-orbital method with the inclusion of correlation effects by GGA+U approach reproduce well the experimental spectra and allow to explain the microscopic origin of the noble metals' magneto-optical response in terms of interband transitions. Although the energy band structures of Cu, Ag, and Au are very similar, there are some distinctive differences in bandwidths and the energy positions of the bands (especially in X and L symmetry points), mainly due to different spin-orbit splitting and differences in the spatial extent of 3 d , 4 d , and 5 d valence wave functions of noble metals. It was found that the small differences in the band positions lead to significant differences in the MO properties of three noble metals. Although the spin-orbit interaction in Au is about six times larger than in Cu, and approximately two times larger than in Ag, the absolute value of Kerr rotation in Au is of the same magnitude as in Cu and one order of magnitude smaller as compared to Ag. The sharp Kerr effect spectral peak in Ag is not due to the electronic interband transitions, but rather to the plasma-edge splitting. The band-by-band decomposition of the Cu, Ag, and Au MO spectra is presented and the

Toxic Compounds Analysis With High Performance Liquid Chromatography Detected By Electro Chemical Detector (Ecd)

OpenAIRE

Hideharu Shintaniq

2014-01-01

The principal area of application of high performance liquid chromatography-electrochemical detector (HPLC-ECD) has been in the analysis of naturally-occurring analytes, such as catecholamines, and pharmaceuticals in biological samples, HPLC-ECD has also applied to the analysis of pesticides and other analytes of interest to the toxicologist. In this paper, toxic area is described. In these, ammatoxins, aromatic amine, nitro-compounds, algal toxins, fungal toxins, pesticides, veterinary drug ...

Daya Bay Antineutrino Detector gas system

Science.gov (United States)

Band, H. R.; Cherwinka, J. J.; Chu, M.-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

2012-11-01

The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experiment. This constant flush also prevents the infiltration of radon or other contaminants into these detecting liquids keeping the internal backgrounds low. Since the Daya Bay antineutrino detectors are immersed in the large water pools of the muon veto system, other gas volumes are needed to protect vital detector cables or gas lines. These volumes are also purged with dry gas. Return gas is monitored for oxygen content and humidity to provide early warning of potentially damaging leaks. The design and performance of the Daya Bay Antineutrino Detector gas system is described.

arXiv Photon detector system performance in the DUNE 35-ton prototype liquid argon time projection chamber

CERN Document Server

Adams, D.L.; Anderson, J.T.; Bagby, L.; Baird, M.; Barr, G.; Barros, N.; Biery, K.; Blake, A.; Blaufuss, E.; Boone, T.; Booth, A.; Brailsford, D.; Buchanan, N.; Chatterjee, A.; Convery, M.; Davies, J.; Dealtry, T.; DeLurgio, P.; Deuerling, G.; Dharmapalan, R.; Djurcic, Z.; Drake, G.; Eberly, B.; Freeman, J.; Glavin, S.; Gomes, R.A.; Goodman, M.C.; Graham, M.; Hahn, A.; Haigh, J.T.; Hartnell, J.; Higuera, A.; Himmel, A.; Insler, J.; Jacobsen, J.; Junk, T.; Kirby, B.; Klein, J.; Kudryavtsev, V.A.; Kutter, T.; Li, Y.; Li, X.; Lin, S.; Martin-Albo, J.; McConkey, N.; Moura, C.A.; Mufson, S.; Nicholls, T.C.; Nowak, J.; Oberling, M.; Paley, J.; Qian, X.; Raaf, J.L.; Rivera, D.; Santucci, G.; Sinev, G.; Spooner, N.J. C.; Stancari, M.; Stancu, I.; Stefan, D.; Stewart, J.; Stock, J.; Strauss, T.; Sulej, R.; Sun, Y.; Thiesse, M.; Thompson, L.F.; Tsai, Y.T.; Wallbank, M.; Warburton, T.K.; Warner, D.; Whittington, D.; Wilson, R.J.; Worcester, M.; Worcester, E.; Yang, T.; Zhang, C.

The 35-ton prototype for the Deep Underground Neutrino Experiment far detector was a single-phase liquid argon time projection chamber with an integrated photon detector system, all situated inside a membrane cryostat. The detector took cosmic-ray data for six weeks during the period of February 1, 2016 to March 12, 2016. The performance of the photon detection system was checked with these data. An installed photon detector was demonstrated to measure the arrival times of cosmic-ray muons with a resolution better than 32 ns, limited by the timing of the trigger system. A measurement of the timing resolution using closely-spaced calibration pulses yielded a resolution of 15 ns for pulses at a level of 6 photo-electrons. Scintillation light from cosmic-ray muons was observed to be attenuated with increasing distance with a characteristic length of $155 \\pm 28$ cm.

Determination of natural in vivo noble-gas concentrations in human blood.

Directory of Open Access Journals (Sweden)

Yama Tomonaga

Full Text Available Although the naturally occurring atmospheric noble gases He, Ne, Ar, Kr, and Xe possess great potential as tracers for studying gas exchange in living beings, no direct analytical technique exists for simultaneously determining the absolute concentrations of these noble gases in body fluids in vivo. In this study, using human blood as an example, the absolute concentrations of all stable atmospheric noble gases were measured simultaneously by combining and adapting two analytical methods recently developed for geochemical research purposes. The partition coefficients determined between blood and air, and between blood plasma and red blood cells, agree with values from the literature. While the noble-gas concentrations in the plasma agree rather well with the expected solubility equilibrium concentrations for air-saturated water, the red blood cells are characterized by a distinct supersaturation pattern, in which the gas excess increases in proportion to the atomic mass of the noble-gas species, indicating adsorption on to the red blood cells. This study shows that the absolute concentrations of noble gases in body fluids can be easily measured using geochemical techniques that rely only on standard materials and equipment, and for which the underlying concepts are already well established in the field of noble-gas geochemistry.

Electric field fluctuations in liquid tellurium alloys a hint to bond character

NARCIS (Netherlands)

Paulick, C.A.; Brinkmann, R.; Elwenspoek, Michael Curt; von Hartrott, M.; Kiehl, M.; Maxim, P.; Quitmann, D.

1985-01-01

Atomic scale electric field fluctuations in liquid tellurium alloys are detected as they induce nuclear spin relaxation rate RQ in noble gas impurity atoms, via quadrupolar interaction. Results for Xe in liquid Ag, Ga, In, Tl, Ge, Sn---Te alloys are discussed, assuming that bonding in these alloys

Noble gas absorption process

International Nuclear Information System (INIS)

Thomas, J.W.

1975-01-01

A method of removing a noble gas from air comprising the use of activated carbon filters in stages in which absorption and desorption steps in succession are conducted in order to increase the capacity of the filters is described. (U.S.)

Stability of Transition-metal Carbides in Liquid Phase Reactions Relevant for Biomass-Based Conversion

NARCIS (Netherlands)

Souza Macêdo, L.; Stellwagen, D.R.; Teixeira da Silva, V.; Bitter, J.H.

2015-01-01

Transition-metal carbides have been employed for biobased conversions aiming to replace the rare noble metals. However, when reactions are in liquid phase, many authors have observed catalyst deactivation. The main routes of deactivation in liquid phase biobased conversions are coke deposition,

Single-laboratory validation of a high-performance liquid chromatographic-diode array detector-fluorescence detector/mass spectrometric method for simultaneous determination of water-soluble vitamins in multivitamin dietary tablets.

Science.gov (United States)

Chen, Pei; Atkinson, Renata; Wolf, Wayne R

2009-01-01

The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 microm, 250 x 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLDIMS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration.

Preparation of bubble damage detectors

International Nuclear Information System (INIS)

Tu Caiqing; Guo Shilun; Wang Yulan; Hao Xiuhong; Chen Changmao; Su Jingling

1997-01-01

Bubble damage detectors have been prepared by using polyacrylamide as detector solid and freon as detector liquid. Tests show that the prepared detectors are sensitive to fast neutrons and have proportionality between bubble number and neutron fluence within a certain range of neutron fluence. Therefore, it can be used as a fast neutron detector and a dosimeter

Daya Bay Antineutrino Detector Gas System

OpenAIRE

Band, H. R.; Cherwinka, J. J.; Chu, M-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

2012-01-01

The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experimen...

Precise 3D track reconstruction algorithm for the ICARUS T600 liquid argon time projection chamber detector

CERN Document Server

Antonello, M

2013-01-01

Liquid Argon Time Projection Chamber (LAr TPC) detectors offer charged particle imaging capability with remarkable spatial resolution. Precise event reconstruction procedures are critical in order to fully exploit the potential of this technology. In this paper we present a new, general approach of three-dimensional reconstruction for the LAr TPC with a practical application to track reconstruction. The efficiency of the method is evaluated on a sample of simulated tracks. We present also the application of the method to the analysis of real data tracks collected during the ICARUS T600 detector operation with the CNGS neutrino beam.

Precise 3D Track Reconstruction Algorithm for the ICARUS T600 Liquid Argon Time Projection Chamber Detector

Directory of Open Access Journals (Sweden)

M. Antonello

2013-01-01

Full Text Available Liquid Argon Time Projection Chamber (LAr TPC detectors offer charged particle imaging capability with remarkable spatial resolution. Precise event reconstruction procedures are critical in order to fully exploit the potential of this technology. In this paper we present a new, general approach to 3D reconstruction for the LAr TPC with a practical application to the track reconstruction. The efficiency of the method is evaluated on a sample of simulated tracks. We present also the application of the method to the analysis of stopping particle tracks collected during the ICARUS T600 detector operation with the CNGS neutrino beam.

Effect of noble gas ion pre-irradiation on deuterium retention in tungsten

NARCIS (Netherlands)

Cheng, L.; Zhao, Z. H.; De Temmerman, G.; Yuan, Y.; Morgan, T. W.; Guo, L. P.; Wang, B.; Zhang, Y.; Wang, B. Y.; Zhang, P.; Cao, X. Z.; Lu, G. H.

2016-01-01

Impurity seeding of noble gases is an effective way of decreasing the heat loads onto the divertor targets in fusion devices. To investigate the effect of noble gases on deuterium retention, tungsten targets have been implanted by different noble gas ions and subsequently exposed to deuterium

Liquid level detector

International Nuclear Information System (INIS)

Dean, A.P.; Pendleton, J.R.

1982-01-01

A device is described for locating the level of the liquid metal in a sodium cooled nuclear reactor by using a movable probe equipped to signal a phase change with null on arrival at the interface between two conductively differing media. (U.K.)

Atomic forces between noble gas atoms, alkali ions, and halogen ions for surface interactions

Science.gov (United States)

Wilson, J. W.; Outlaw, R. A.; Heinbockel, J. H.

1988-01-01

The components of the physical forces between noble gas atoms, alkali ions, and halogen ions are analyzed and a data base developed from analysis of the two-body potential data, the alkali-halide molecular data, and the noble gas crystal and salt crystal data. A satisfactory global fit to this molecular and crystal data is then reproduced by the model to within several percent. Surface potentials are evaluated for noble gas atoms on noble gas surfaces and salt crystal surfaces with surface tension neglected. Within this context, the noble gas surface potentials on noble gas and salt crystals are considered to be accurate to within several percent.

A Monte Carlo Model for Neutron Coincidence Counting with Fast Organic Liquid Scintillation Detectors

International Nuclear Information System (INIS)

Gamage, Kelum A.A.; Joyce, Malcolm J.; Cave, Frank D.

2013-06-01

Neutron coincidence counting is an established, nondestructive method for the qualitative and quantitative analysis of nuclear materials. Several even-numbered nuclei of the actinide isotopes, and especially even-numbered plutonium isotopes, undergo spontaneous fission, resulting in the emission of neutrons which are correlated in time. The characteristics of this i.e. the multiplicity can be used to identify each isotope in question. Similarly, the corresponding characteristics of isotopes that are susceptible to stimulated fission are somewhat isotope-related, and also dependent on the energy of the incident neutron that stimulates the fission event, and this can hence be used to identify and quantify isotopes also. Most of the neutron coincidence counters currently used are based on 3 He gas tubes. In the 3 He-filled gas proportional-counter, the (n, p) reaction is largely responsible for the detection of slow neutrons and hence neutrons have to be slowed down to thermal energies. As a result, moderator and shielding materials are essential components of many systems designed to assess quantities of fissile materials. The use of a moderator, however, extends the die-away time of the detector necessitating a larger coincidence window and, further, 3 He is now in short supply and expensive. In this paper, a simulation based on the Monte Carlo method is described which has been performed using MCNPX 2.6.0, to model the geometry of a sector-shaped liquid scintillation detector in response to coincident neutron events. The detection of neutrons from a mixed-oxide (MOX) fuel pellet using an organic liquid scintillator has been simulated for different thicknesses of scintillators. In this new neutron detector, a layer of lead has been used to reduce the gamma-ray fluence reaching the scintillator. The effect of lead for neutron detection has also been estimated by considering different thicknesses of lead layers. (authors)

First 10 kg of naked Germanium detectors in liquid nitrogen installed in the GENIUS-Test-Facility

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.; Chkvorets, O.; Krivosheina, I.V.; Strecker, H.; Tomei, C.

2003-01-01

The first four naked high-purity Germanium detectors were installed successfully in liquid nitrogen in the GENIUS-Test-Facility in the GRAN SASSO Underground Laboratory on May 5, 2003. This is the first time ever that this novel technique aiming at extreme background reduction in search for rare decays is going to be tested underground. First operational parameters are presented

Analysis of phenolic acids by ionic liquid-in-water microemulsion liquid chromatography coupled with ultraviolet and electrochemical detector.

Science.gov (United States)

Peng, Li-Qing; Cao, Jun; Du, Li-Jing; Zhang, Qi-Dong; Shi, Yu-Tin; Xu, Jing-Jing

2017-05-26

An environmentally friendly ionic liquid-in-water (IL/W) microemulsion was established and applied as mobile phase in microemulsion liquid chromatography (MELC) with ultraviolet (UV) detection or electrochemical detector (ECD) for analysis of phenolic compounds in real samples. The optimal condition of the method was using the best composition of microemulsion (0.2% w/v [HMIM]PF 6 , 1.0% w/v SDS, 3.0% w/v n-butanol, 95.8% v/v water, pH 2.5) with UV detection. The validation results indicated that the method provided high degree of sensitivity, precision and accuracy with the low limit of detections ranged from 17.9-238ng/mL, satisfactory mean recovery values in the range of 80.1-105% and good linearity (r 2 >0.9994). Additionally, this method exhibited high selectivity and resolution for the analytes and was more eco-friendly compared with traditional MELC method. Consequently, the established IL/W MELC method was successfully applied to simultaneously separate and determine target compounds in Danshen sample and its preparation. Copyright © 2017 Elsevier B.V. All rights reserved.

Proposal for a Full-Scale Prototype Single-Phase Liquid Argon Time Projection Chamber and Detector Beam Test at CERN

CERN Document Server

Kutter, T

2015-01-01

The Deep Underground Neutrino Experiment (DUNE) will use a large liquid argon (LAr) detector to measure the CP violating phase, determine the neutrino mass hier- archy and perform precision tests of the three-flavor paradigm in long-baseline neutrino oscillations. The detector will consist of four modules each with a fiducial mass of 10 kt of LAr and due to its unprecedented size will allow sensitive searches for proton decay and the detection and measurement of electron neutrinos from core collapse supernovae [1]. The first 10 kt module will use single-phase LAr detection technique and be itself modular in design. The successful manufacturing, installation and operation of several full-scale detector components in a suitable configuration represents a critical engineering milestone prior to the construction and operation of the first full 10 kt DUNE detector module at the SURF underground site. A charged particle beam test of a prototype detector will provide critical calibration measurements as well as inva...

Steady-state ozone concentration in radiation induced noble gas-oxygen discharges

International Nuclear Information System (INIS)

Elsayed-Ali, H.E.; Miley, G.H.

1985-01-01

Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O 2 and noble gas-O 2 -SF 6 mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10 15 eV.cm -3 .s -1 . The experimental apparatus and proceedure were previously described. The experimentally observed stead-state ozone concentrations in noble gas-O 2 discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O 2 -SF 6 mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF 6 addition. This observation was contrary to only a small increase observed after SF 6 addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O 2 discharges

Filamentous fungi associated with natural infection of noble rot on withered grapes.

Science.gov (United States)

Lorenzini, M; Simonato, B; Favati, F; Bernardi, P; Sbarbati, A; Zapparoli, G

2018-05-02

The effects of noble rot infection of grapes on the characteristics of different types of wine, including Italian passito wine, are well known. Nevertheless, there is still little information on filamentous fungi associated with noble-rotten grapes. In this study, withered Garganega grapes for passito wine production, naturally infected by noble rot, were analyzed and compared to sound grapes. Skin morphology and fungal population on berry surfaces were analyzed. Scanning electron microscopy analysis revealed microcracks, germination conidia and branched hyphae on noble-rotten berries. Penicillium, Aureobasidium and Cladosporium were the most frequent genera present. Analysis of single berries displayed higher heterogeneity of epiphytic fungi in those infected by noble-rot than in sound berries. Penicillium adametzoides, Cladosporium cladospoirioides and Coniochaeta polymorpha were recovered. These, to the best of our knowledge, had never been previously isolated from withered grapes and, for C. polymorpha, from grapevine. This study provided novel data on noble rot mycobiota and suggests that fungi that co-habit with B. cinerea could have an important role on grape and wine quality. Copyright © 2018 Elsevier B.V. All rights reserved.

Ionic liquids in the synthesis of nanoobjects

International Nuclear Information System (INIS)

Tarasova, Natalia P; Smetannikov, Yurii V; Zanin, A A

2010-01-01

Data on the usage of the novel green solvents, ionic liquids, in the synthesis of nanoobjects and their stabilization are considered. The information is structured according to the resulting products of the synthetic processes: nanoparticles of noble metals, nanoparticles of non-metals, nanoparticles of metal oxides and chalcogenides, nanocomposites, and highly dispersed polymers. The conclusion is made that the ionic liquids might determine the structure and the properties of the nanoobjects, thus opening new fundamental and technological horizons in nanochemistry.

Cryogenic system for collecting noble gases from boiling water reactor off-gas

International Nuclear Information System (INIS)

Schmauch, G.E.

1973-01-01

In boiling water reactors, noncondensible gases are expelled from the main condenser. This off-gas stream is composed largely of radiolytic hydrogen and oxygen, air in-leakage, and traces of fission product krypton and xenon. In the Air Products' treatment system, the stoichiometric hydrogen and oxygen are reacted to form water in a catalytic recombiner. The design of the catalytic recombiner is an extension of industrial gas technology developed for purification of argon and helium. The off-gas after the recombiner is processed by cryogenic air-separation technology. The gas is compressed, passed into a reversing heat exchanger where water vapor and carbon dioxide are frozen out, further cooled, and expanded into a distillation column where refrigeration is provided by addition of liquid nitrogen. More than 99.99 percent of the krypton and essentially 100 percent of the xenon entering the column are accumulated in the column bottoms. Every three to six months, the noble-gas concentrate accumulated in the column bottom is removed as liquid, vaporized, diluted with steam, mixed with hydrogen in slight excess of oxygen content, and fed to a small recombiner where all the oxygen reacts to form water. The resulting gas stream, containing from 20 to 40 percent noble gases, is compressed into small storage cylinders for indefinite retention or for decay of all fission gases except krypton-85, followed by subsequent release under controlled conditions and favorable meteorology. This treatment system is based on proven technology that is practiced throughout the industrial gas industry. Only the presence of radioactive materials in the process stream and the application in a nuclear power plant environment are new. Adaptations to meet these new conditions can be made without sacrificing performance, reliability, or safety

EOSN: A TOUGH2 module for noble gases

Energy Technology Data Exchange (ETDEWEB)

Shan, Chao; Pruess, Karsten

2003-03-07

We developed a new fluid property module for TOUGH2, called EOSN, to simulate transport of noble gases in the subsurface. Currently, users may select any of five different noble gases as well as CO2, two at a time. For the three gas components (air and two user-specified noble gases) in EOSN, the Henry's coefficients and the diffusivities in the gas phase are no longer assumed constants, but are temperature dependent. We used the Crovetto et al. (1982) model to estimate Henry's coefficients, and the Reid et al. (1987) correlations to calculate gas phase diffusivities. The new module requires users to provide names of the selected noble gases, which properties are provided internally. There are options for users to specify any (non-zero) molecular weights and half-lives for the gas components. We provide two examples to show applications of TOUGH2IEOSN. While temperature effects are relatively insignificant for one example problem where advection is dominant, they cause almost an order of magnitude difference for the other case where diffusion becomes a dominant process and temperature variations are relatively large. It appears that thermodynamic effects on gas diffusivities and Henry's coefficients can be important for low-permeability porous media and zones with large temperature variations.

EOSN: A TOUGH2 module for noble gases

International Nuclear Information System (INIS)

Shan, Chao; Pruess, Karsten

2003-01-01

We developed a new fluid property module for TOUGH2, called EOSN, to simulate transport of noble gases in the subsurface. Currently, users may select any of five different noble gases as well as CO2, two at a time. For the three gas components (air and two user-specified noble gases) in EOSN, the Henry's coefficients and the diffusivities in the gas phase are no longer assumed constants, but are temperature dependent. We used the Crovetto et al. (1982) model to estimate Henry's coefficients, and the Reid et al. (1987) correlations to calculate gas phase diffusivities. The new module requires users to provide names of the selected noble gases, which properties are provided internally. There are options for users to specify any (non-zero) molecular weights and half-lives for the gas components. We provide two examples to show applications of TOUGH2IEOSN. While temperature effects are relatively insignificant for one example problem where advection is dominant, they cause almost an order of magnitude difference for the other case where diffusion becomes a dominant process and temperature variations are relatively large. It appears that thermodynamic effects on gas diffusivities and Henry's coefficients can be important for low-permeability porous media and zones with large temperature variations

Standardization of heparins by means of high performance liquid chromatography equipped with a low angle laser light scattering detector

NARCIS (Netherlands)

Hennink, W.E.; van den Berg, J.W.A.; Feijen, Jan

1987-01-01

This study shows that HPLC-LALLS (high performance liquid chromatography with a light-scattering detector) is a convenient and reliable method for the characterization of standard heparin samples, provided that polyelectrolyte artefacts are suppressed by a suitable dialysis procedure. The method has

Steady-state ozone concentrations in radiation induced noble gas-oxygen discharges

International Nuclear Information System (INIS)

Elsayed-Ali, H.E.; Miley, G.H.

1985-01-01

Measurements of steady-state ozone concentrations in continuous radiation induced noble gas-O/sub 2/ and noble gas-o/sub 2/-SF/sub 6/ mixtures has been accomplished. The discharges were created through the bombardment of the gases with energetic particles from the boron-10 (n,α) lithium-7 nuclear reaction. Three noble gases were studied, He, Ne, and Ar at partial pressures of few hundred Torr. The dose rates studied were in the order of 10/sup 15/ eV . cm/sup -3/ . s/sup -1/. The experimental apparatus and procedure were previously described. The experimentally observed steady-state ozone concentrations in noble gas-O/sub 2/ discharges were about an order of magnitude lower than that observed for oxygen radiolysis at similar dose rates. These results were physically explained by an enhanced role of negative ionic reactions with ozone causing its destruction. In noble gas-O/sub 2/-SF/sub 6/ mixtures, the steady-state ozone concentrations were found to be significantly higher (3-6 times) than that without the SF/sub 6/ addition. This observation was contrary to only a small increase observed after SF/sub 6/ addition to a few hundred Torr oxygen and is explained by an enhanced rate of electron dissociative attachment of ozone in noble gas-O/sub 2/ discharges

Engineering noble metal nanomaterials for environmental applications

Science.gov (United States)

Li, Jingguo; Zhao, Tingting; Chen, Tiankai; Liu, Yanbiao; Ong, Choon Nam; Xie, Jianping

2015-04-01

Besides being valuable assets in our daily lives, noble metals (namely, gold, silver, and platinum) also feature many intriguing physical and chemical properties when their sizes are reduced to the nano- or even subnano-scale; such assets may significantly increase the values of the noble metals as functional materials for tackling important societal issues related to human health and the environment. Among which, designing/engineering of noble metal nanomaterials (NMNs) to address challenging issues in the environment has attracted recent interest in the community. In general, the use of NMNs for environmental applications is highly dependent on the physical and chemical properties of NMNs. Such properties can be readily controlled by tailoring the attributes of NMNs, including their size, shape, composition, and surface. In this feature article, we discuss recent progress in the rational design and engineering of NMNs with particular focus on their applications in the field of environmental sensing and catalysis. The development of functional NMNs for environmental applications is highly interdisciplinary, which requires concerted efforts from the communities of materials science, chemistry, engineering, and environmental science.

Engineering noble metal nanomaterials for environmental applications.

Science.gov (United States)

Li, Jingguo; Zhao, Tingting; Chen, Tiankai; Liu, Yanbiao; Ong, Choon Nam; Xie, Jianping

2015-05-07

Besides being valuable assets in our daily lives, noble metals (namely, gold, silver, and platinum) also feature many intriguing physical and chemical properties when their sizes are reduced to the nano- or even subnano-scale; such assets may significantly increase the values of the noble metals as functional materials for tackling important societal issues related to human health and the environment. Among which, designing/engineering of noble metal nanomaterials (NMNs) to address challenging issues in the environment has attracted recent interest in the community. In general, the use of NMNs for environmental applications is highly dependent on the physical and chemical properties of NMNs. Such properties can be readily controlled by tailoring the attributes of NMNs, including their size, shape, composition, and surface. In this feature article, we discuss recent progress in the rational design and engineering of NMNs with particular focus on their applications in the field of environmental sensing and catalysis. The development of functional NMNs for environmental applications is highly interdisciplinary, which requires concerted efforts from the communities of materials science, chemistry, engineering, and environmental science.

First-principles study of noble gas stability in ThO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Shao, Kuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Han, Han, E-mail: hanhanfudan@gmail.com [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhang, Wei [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Wang, Hui [School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003 (China); Wang, Chang-Ying; Guo, Yong-Liang [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Ren, Cui-Lan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Huai, Ping, E-mail: huaiping@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2017-07-15

The stability of noble gases (He, Ne, Ar, Kr and Xe) in thorium dioxide is studied by means of density functional theory. The computations are performed considering insertion sites of ThO{sub 2}, including the interstitial sites, the thorium vacancies, the oxygen-thorium di-vacancy and three types of Schottky defects. Our results show that there is an approximately linear relation between the energies and the atomic radii. As the size of the noble gas atom increases, the noble gas atoms energetically prefer to incorporate into large vacancy defects rather than into interstitial positions. Moreover, the binding energy of Kr or Xe interstitial in a Schottky defect is larger than the formation energy of a Schottky defect, suggesting the Schottky defects are thermodynamically favorable in the presence of these noble gas atoms. The charged defects are also considered for noble gas atoms trapped in Th and O vacancies.

Detector to detector corrections: a comprehensive experimental study of detector specific correction factors for beam output measurements for small radiotherapy beams

DEFF Research Database (Denmark)

Azangwe, Godfrey; Grochowska, Paulina; Georg, Dietmar

2014-01-01

-doped aluminium oxide (Al2O3:C), organic plastic scintillators, diamond detectors, liquid filled ion chamber, and a range of small volume air filled ionization chambers (volumes ranging from 0.002 cm3 to 0.3 cm3). All detector measurements were corrected for volume averaging effect and compared with dose ratios...... measurements, the authors recommend the use of detectors that require relatively little correction, such as unshielded diodes, diamond detectors or microchambers, and solid state detectors such as alanine, TLD, Al2O3:C, or scintillators....

Charged Particle Identification using the Liquid Xenon Calorimeter of the CMD-3 Detector

CERN Document Server

Akhmetshin, R R; Anisenkov, A V; Aulchenko, V M; Banzarov, V Sh; Bashtovoy, N S; Bondar, A E; Bragin, A V; Eidelman, S I; Epifanov, D A; Epshteyn, L B; Erofeev, A L; Fedotovich, G V; Gayazov, S E; Grebenuk, A A; Gribanov, S S; Grigoriev, D N; Ignatov, F V; Ivanov, V L; Karpov, S V; Kazanin, V F; Korobov, A A; Kovalenko, O A; Kozyrev, A N; Kozyrev, E A; Krokovny, P P; Kuzmenko, A E; Kuzmin, A S; Logashenko, I B; Lukin, P A; Mikhailov, K Yu; Okhapkin, V S; Pestov, Yu N; Popov, A S; Razuvaev, G P; Ruban, A A; Ryskulov, N M; Ryzhenenkov, A E; Shebalin, V E; Shemyakin, D N; Shwartz, B A; Sibidanov, A L; Solodov, E P; Talyshev, A A; Titov, V M; Vorobiov, A I; Yudin, Yu V

2017-01-01

This paper describes a currently being developed procedure of the charged particle identification for CMD-3 detector, installed at the VEPP-2000 collider. The procedure is based on the application of the boosted decision trees classification method, and uses as input variables, among others, the specific energy losses of charged particle in the layers of the liquid Xenon calorimeter. The efficiency of the procedure is demonstrated by an example of the extraction of events of e+e- to K+K- process in the center of mass energy range from 1.8 to 2.0 GeV.

Stanford's big new detector

International Nuclear Information System (INIS)

Anon.

1984-01-01

A detector constructed for the Standford Linear Collider is described. It consists of a central drift chamber in the field of a surrounding superconducting solenoid. Furthermore included are a Cherenkov ring imaging detector for particle identification and a liquid argon calorimeter. (HSI).

Radiolytic model of CN Cofrentes using BWRVIA: analysis of the effectiveness of mitigation in locations of the vessel with application of noble metal son-line; Modelo radiolitico de C. N: Cofrentes utilizando el BWRVIA: analisis de la efectividad de mitigacion en localizaciones de la vasija con aplicacion de metales nobles on-line

Energy Technology Data Exchange (ETDEWEB)

Martin-Serrano Ledesma, C.; Sanchez Zapata, J. D.

2012-07-01

The effectiveness of mitigation is found from two chemical parameters: electrochemical potential (pm-a hydrogen injection) and Molar Ratio (for the application of noble metals). EPRI code exists, the BWRVIA (BWR Vessel Internals Application,) which enables setting model the impact radiolysis of water, the balance of liquid-vapor phase and recirculation have on the chemical variation of these parameters.

Technique for detecting liquid metal leaks

International Nuclear Information System (INIS)

Bauerle, J.E.

1979-01-01

In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector

Recovery of noble metals from fission products

International Nuclear Information System (INIS)

Jenson, G.A.; Platt, A.M.; Mellinger, G.B.; Bjorklund, W.J.

1982-11-01

Scoping studies were started in 1979 to develop a cost-effective, waste-management-compatible process to extract noble metals from fission products. The process, involving the reaction with glassmelting chemicals, a metal oxide (PbO), and a reducing agent (charcoal), was demonstrated for recovering noble metals from simulated high-level waste oxides. The process has now been demonstrated on a laboratory scale (100 g) using irradiated fuels. Recoveries in the recovered lead averaged 80% for Pd, 60% for Rh, and 14% Ru. The resulting glass product was homogeneous in appearance, and the chemical durability was comparable to other waste oxides

Low Energy Neutrino Astronomy in the future large-volume liquid-scintillator detector LENA

International Nuclear Information System (INIS)

Wurm, Michael; Feilitzsch, F V; Goeger-Neff, M; Lewke, T; Undagoitia, T Marrodan; Oberauer, L; Potzel, W; Todor, S; Winter, J

2008-01-01

The recent successes in neutrino physics prove that liquid-scintillator detectors allow to combine high energy resolution, efficient means of background reduction, and a large detection volume. In the planned LENA (Low Energy Neutrino Astronomy) experiment, a target mass of 50 kt will enable the investigation of a variety of terrestrial and astrophysical neutrino sources. The high-statistics spectroscopy of geoneutrinos, solar neutrinos and supernova neutrinos will provide new insights in the heat production processes of Earth and Sun, and the workings of a gravitational collapse. The same measurements will as well investigate neutrino properties as oscillation parameters and mass hierarchy. A first spectroscopic measurement of the low flux of diffuse supernova neutrino background is within the sensitivity of the LENA detector. Finally, a life-time limit of several 1034 years can be set to the proton decay into proton and anti-neutrino, testing the predictions of SUSY theory. The present contribution includes a review of the scientific studies that were performed in the last years as well as a report on currently on-going R and D activities.

Low Energy Neutrino Astronomy in the future large-volume liquid-scintillator detector LENA

Energy Technology Data Exchange (ETDEWEB)

Wurm, Michael; Feilitzsch, F V; Goeger-Neff, M; Lewke, T; Undagoitia, T Marrodan; Oberauer, L; Potzel, W; Todor, S; Winter, J [E15 Chair for Astroparticle Physics, Technische Universitat Miinchen, Physik Department, James-Franck-Str., D-85748 Garching (Germany)

2008-11-01

The recent successes in neutrino physics prove that liquid-scintillator detectors allow to combine high energy resolution, efficient means of background reduction, and a large detection volume. In the planned LENA (Low Energy Neutrino Astronomy) experiment, a target mass of 50 kt will enable the investigation of a variety of terrestrial and astrophysical neutrino sources. The high-statistics spectroscopy of geoneutrinos, solar neutrinos and supernova neutrinos will provide new insights in the heat production processes of Earth and Sun, and the workings of a gravitational collapse. The same measurements will as well investigate neutrino properties as oscillation parameters and mass hierarchy. A first spectroscopic measurement of the low flux of diffuse supernova neutrino background is within the sensitivity of the LENA detector. Finally, a life-time limit of several 1034 years can be set to the proton decay into proton and anti-neutrino, testing the predictions of SUSY theory. The present contribution includes a review of the scientific studies that were performed in the last years as well as a report on currently on-going R and D activities.

Analysis of metalaxyl racemate using high performance liquid chromatography coupled with four kinds of detectors.

Science.gov (United States)

Chen, Tao; Fan, Jun; Gao, Ruiqi; Wang, Tai; Yu, Ying; Zhang, Weiguang

2016-10-07

Chiral stationary phase-high performance liquid chromatography coupled with various detectors has been one of most commonly used methods for analysis and separation of chiral compounds over the past decades. Various detectors exhibit different characteristics in qualitative and quantitative studies under different chromatographic conditions. Herein, a comparative evaluation of HPLC coupled with ultraviolet, optical rotation, refractive index, and evaporative light scattering detectors has been conducted for qualitative and quantitative analyses of metalaxyl racemate. Effects of separation conditions on the peak area ratio between two enantiomers, including sample concentration, column temperature, mobile phase composition, as well as flow rate, have been investigated in detail. In addition, the limits of detection, the limits of quantitation, quantitative range and precision for these two enantiomers by using four detectors have been also studied. As indicated, the chromatographic separation conditions have been slight effects on ultraviolet and refractive index detections and the peak area ratio between two enantiomers remains almost unchanged, but the evaporative light scattering detection has been significantly affected by the above-mentioned chromatographic conditions and the corresponding peak area ratios varied greatly. Moreover, the limits of detection, the limits of quantitation, and the quantitative ranges of two enantiomers with UV detection were remarkably lower by 1-2 magnitudes than the others. Copyright © 2016 Elsevier B.V. All rights reserved.

Activity measurements of radioactive solutions by liquid scintillation counting and pressurized ionization chambers and Monte Carlo simulations of source-detector systems for metrology

International Nuclear Information System (INIS)

Amiot, Marie-Noelle

2013-01-01

The research works 'Activity measurements of radioactive solutions by liquid scintillation and pressurized ionization chambers and Monte Carlo simulations of source-detector systems' was presented for the graduation: 'Habilitation a diriger des recherches'. The common thread of both themes liquid scintillation counting and pressurized ionization chambers lies in the improvement of the techniques of radionuclide activity measurement. Metrology of ionization radiation intervenes in numerous domains, in the research, in the industry including the environment and the health, which are subjects of constant concern for the world population these last years. In this big variety of applications answers a large number of radionuclides of diverse disintegration scheme and under varied physical forms. The presented works realized within the National Laboratory Henri Becquerel have for objective to assure detector calibration traceability and to improve the methods of activity measurements within the framework of research projects and development. The improvement of the primary and secondary activity measurement methods consists in perfecting the accuracy of the measurements in particular by a better knowledge of the parameters influencing the detector yield. The works of development dealing with liquid scintillation counting concern mainly the study of the response of liquid scintillators to low energy electrons as well as their linear absorption coefficients using synchrotron radiation. The research works on pressurized ionization chambers consist of the study of their response to photons and electrons by experimental measurements compared to the simulation of the source-detector system using Monte Carlo codes. Besides, the design of a new type of ionization chamber with variable pressure is presented. This new project was developed to guarantee the precision of the amount of activity injected into the patient within the framework of diagnosis examination

Spill-Detector-and-Shutoff Device

Science.gov (United States)

Jarvis, M. R.; Fulton, D. S.

1985-01-01

Overflow in liquid chromatography systems rapidly detected and stopped. Spill-detector-and-shutoff device incorporated into liquid-chromatography system. When liquid from output nozzle spills on liquid sensor, device automatically shuts off pump and releases solenoid to pinch off flow in tube. Device uses common type of alarm circuit reset manually before normal operation resumes.

Metal-organic frameworks for adsorption and separation of noble gases

Energy Technology Data Exchange (ETDEWEB)

Allendorf, Mark D.; Greathouse, Jeffery A.; Staiger, Chad

2017-05-30

A method including exposing a gas mixture comprising a noble gas to a metal organic framework (MOF), including an organic electron donor and an adsorbent bed operable to adsorb a noble gas from a mixture of gases, the adsorbent bed including a metal organic framework (MOF) including an organic electron donor.

Ab initio theory of noble gas atoms in bcc transition metals.

Science.gov (United States)

Jiang, Chao; Zhang, Yongfeng; Gao, Yipeng; Gan, Jian

2018-06-18

Systematic ab initio calculations based on density functional theory have been performed to gain fundamental understanding of the interactions between noble gas atoms (He, Ne, Ar and Kr) and bcc transition metals in groups 5B (V, Nb and Ta), 6B (Cr, Mo and W) and 8B (Fe). Our charge density analysis indicates that the strong polarization of nearest-neighbor metal atoms by noble gas interstitials is the electronic origin of their high formation energies. Such polarization becomes more significant with an increasing gas atom size and interstitial charge density in the host bcc metal, which explains the similar trend followed by the unrelaxed formation energies of noble gas interstitials. Upon allowing for local relaxation, nearby metal atoms move farther away from gas interstitials in order to decrease polarization, albeit at the expense of increasing the elastic strain energy. Such atomic relaxation is found to play an important role in governing both the energetics and site preference of noble gas atoms in bcc metals. Our most notable finding is that the fully relaxed formation energies of noble gas interstitials are strongly correlated with the elastic shear modulus of the bcc metal, and the physical origin of this unexpected correlation has been elucidated by our theoretical analysis based on the effective-medium theory. The kinetic behavior of noble gas atoms and their interaction with pre-existing vacancies in bcc transition metals have also been discussed in this work.

Diverging effects of isotopic fractionation upon molecular diffusion of noble gases in water: mechanistic insights through ab initio molecular dynamics simulations.

Science.gov (United States)

Pinto de Magalhães, Halua; Brennwald, Matthias S; Kipfer, Rolf

2017-03-22

Atmospheric noble gases are routinely used as natural tracers to analyze gas transfer processes in aquatic systems. Their isotopic ratios can be employed to discriminate between different physical transport mechanisms by comparison to the unfractionated atmospheric isotope composition. In many applications of aquatic systems molecular diffusion was thought to cause a mass dependent fractionation of noble gases and their isotopes according to the square root ratio of their masses. However, recent experiments focusing on isotopic fractionation within a single element challenged this broadly accepted assumption. The determined fractionation factors of Ne, Ar, Kr and Xe isotopes revealed that only Ar follows the prediction of the so-called square root relation, whereas within the Ne, Kr and Xe elements no mass-dependence was found. The reason for this unexpected divergence of Ar is not yet understood. The aim of our computational exercise is to establish the molecular-resolved mechanisms behind molecular diffusion of noble gases in water. We make the hypothesis that weak intermolecular interactions are relevant for the dynamical properties of noble gases dissolved in water. Therefore, we used ab initio molecular dynamics to explicitly account for the electronic degrees of freedom. Depending on the size and polarizability of the hydrophobic particles such as noble gases, their motion in dense and polar liquids like water is subject to different diffusive regimes: the inter-cavity hopping mechanism of small particles (He, Ne) breaks down if a critical particle size achieved. For the case of large particles (Kr, Xe), the motion through the water solvent is governed by mass-independent viscous friction leading to hydrodynamical diffusion. Finally, Ar falls in between the two diffusive regimes, where particle dispersion is propagated at the molecular collision time scale of the surrounding water molecules.

First ECR-Ionized Noble Gas Radioisotopes at ISOLDE

CERN Document Server

Wenander, F; Gaubert, G; Jardin, P; Lettry, Jacques

2004-01-01

The production of light noble gas radioisotopes with high ionization potentials has been hampered by modest ionization efficiencies for standard plasma ion-sources. However, the decay losses are minimal as the lingering time of light noble gases within plasma ion-sources is negligible when compared to its diffusion out of the target material. Previous singly charged ECRIS have shown a higher efficiency but also a lingering time of the order of 1 s and a total weight that prevents remote handling by the ISOLDE robot. The compact MINIMONO efficiently addressed the lingering time and weight issues. In addition, the MINIMONO maintained the high off-line ionization efficiency for light noble gases. This paper describes a standard ISOLDE target unit equipped with a MINIMONO ion-source and the first tests. The ion-source has been tested off-line and equipped with a CaO target for on-line tests. Valuable information was gained about high current (100-500 muA) transport through the ISOLDE mass separators designed for ...

Recent Experimental Advances to Determine (noble) Gases in Waters

Science.gov (United States)

Kipfer, R.; Brennwald, M. S.; Huxol, S.; Mächler, L.; Maden, C.; Vogel, N.; Tomonaga, Y.

2013-12-01

In aquatic systems noble gases, radon, and bio-geochemically conservative transient trace gases (SF6, CFCs) are frequently applied to determine water residence times and to reconstruct past environmental and climatic conditions. Recent experimental breakthroughs now enable ● to apply the well-established concepts of terrestrial noble gas geochemistry in waters to the minute water amounts stored in sediment pore space and in fluid inclusions (A), ● to determine gas exchange processes on the bio-geochemical relevant time scales of minutes - hours (B), and ● to separate diffusive and advective gas transport in soil air (C). A. Noble-gas analysis in water samples (transport in the pore space and identifying the origin of bio- and geogenic fluids in (un) consolidated sediments [1]. Advanced techniques that combine crushing and sieving speleothem samples in ultra-high-vacuum to a specific grain size allow to separate air and water-bearing fluid inclusions and thus enables noble-gas-based reconstruction of environmental conditions from water masses as small as 1mg [2]. B. The coupling of noble gas analysis with approaches of gas chromatography permits combined analysis of noble gases and other gases species (e.g., SF6, CFCs, O2, N2) from a single water sample. The new method substantially improves ground water dating by SF6 and CFCs as excess air is quantified from the same sample and hence can adequately be corrected for [3]. Portable membrane-inlet mass spectrometers enable the quasi-continuous and real-time analysis of noble gases and other dissolved gases directly in the field, allowing, for instance, quantification of O2 turnover rates on small time scales [4]. C. New technical developments perfect 222Rn analysis in water by the synchronous the determination of the short-lived 220Rn. The combined 220,222Rn analysis sheds light on the emanation behaviour of radon by identifying soil water content to be the crucial control of 220Rn occurrence in the environment

Development of a partitioning method for the management of high-level liquid waste

International Nuclear Information System (INIS)

Kubota, M.; Dojiri, S.; Yamaguchi, I.; Morita, Y.; Yamagishi, I.; Kobayashi, T.; Tani, S.

1989-01-01

Fundamental studies especially focused on the separation of neptunium and technetium have been carried out to construct the advanced partitioning process of fractioning elements in a high-level liquid waste into four groups: transuranium elements, technetium-noble metals, strontium-cesium, and other elements. For the separation of neptunium by solvent extraction, DIDPA proved excellent for extracting Np(V), and its extraction rate was accelerated by hydrogen peroxide. Np(V) was found to be also separated quantitatively as precipitate with oxalic acid. For the separation of technetium, the denitration with formic acid was effective in precipitating it along with noble metals, and the adsorption with activated carbon was also effective for quantitative separation. Through these fundamental studies, the advanced partitioning process is presented as the candidate to be examined with an actual high-level liquid waste

Extraction of butyltins from sediments and their determination by liquid chromatography interfaced to inductively coupled plasma atomic emission detector

International Nuclear Information System (INIS)

Rivaro, P.; Frache, R.

2000-01-01

A liquid-liquid extraction of the butyltin compounds from sediment, suitable for their subsequent following determination by high performance liquid chromatography-hydride generation inductively coupled plasma atomic emission detector system, is proposed. Recoveries of 86%, 80% and 42% for tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) respectively were achieved. The relative detection limits of butyltin compounds by this method ranged from 27 to 62 ng of tin per gram of dry sediment. The method was applied to real sediment samples collected in the Venice lagoon (Italy). The results showed that, despite the restrictions on the use of butyltin contained in antifoulting paints, a considerable amount of organotin compounds is still present in Venice sediments [it

Effective Giromagnetic Ratios in Artifical Nuclear Magnetization Pumping of the Noble Gases Mix

Directory of Open Access Journals (Sweden)

Popov E.N.

2015-01-01

Full Text Available Dynamic of the nuclear magnetization of the two noble gases mix was studied in this research. Nuclear magnetization pumped along the induction of external magnetic field. Vector of nuclear magnetization is given a tilt by the week rotational magnetic field, which makes NMR for noble gases. Interaction between the nuclear magnetic moments of the different noble gases adducted to shifts at the frequency of nuclear moments precession in external magnetic field. Effective gyromagnetic ratios of the nuclear of noble gases is defined and it different from the tabulated value. There is theoretical calculation of effective gyromagnetic ratios in this research.

Noble Estate Self-Government in Russia: Between the State and Civil Society

Directory of Open Access Journals (Sweden)

Alexander Yu. Morozov

2016-10-01

Full Text Available This article is devoted to assessing the role of noble self-governance in the history of Russia. According to Boris Mironov, before the Great Reforms of the 1860s, each noble assembly was a part of civil society. This point of view has aroused objections and debate among Russian historians. Morozov analyzed the historiographical aspect of the problem and demonstrated the impact of the socio-political context of their scientific work on Russian historians. In his opinion, from a purely legal point of view, there is reason to conclude that the autonomy of noble assemblies increased in the first half of the 19th century. However, the question of the extent to which these opportunities were realized in practice has been poorly studied. In the literature, there are examples of effective methods of influencing the government at the noble assemblies despite legal restrictions, as well as examples of noble assemblies that did not restrain the arbitrariness of the crown authority, did not protect their members from its abuse, and did not serve as the expression of public opinion. Mironov’s attempt to place in doubt the fact of the widespread presence of absenteeism seems unconvincing to Morozov. However, he agrees with Mironov that after 1861, the nobility really became a part of civil society, because the activity of noble organizations increased substantially in many different directions, including the political. For almost half a century of its history, the noble corporate organization evolved from a traditional institution into a civil one, which retained many features of traditional organization.

Systematic implementation of spectral CT with a photon counting detector for liquid security inspection

Science.gov (United States)

Xu, Xiaofei; Xing, Yuxiang; Wang, Sen; Zhang, Li

2018-06-01

X-ray liquid security inspection system plays an important role in homeland security, while the conventional dual-energy CT (DECT) system may have a big deviation in extracting the atomic number and the electron density of materials in various conditions. Photon counting detectors (PCDs) have the capability of discriminating the incident photons of different energy. The technique becomes more and more mature in nowadays. In this work, we explore the performance of a multi-energy CT imaging system with a PCD for liquid security inspection in material discrimination. We used a maximum-likelihood (ML) decomposition method with scatter correction based on a cross-energy response model (CERM) for PCDs so that to improve the accuracy of atomic number and electronic density imaging. Experimental study was carried to examine the effectiveness and robustness of the proposed system. Our results show that the concentration of different solutions in physical phantoms can be reconstructed accurately, which could improve the material identification compared to current available dual-energy liquid security inspection systems. The CERM-base decomposition and reconstruction method can be easily used to different applications such as medical diagnosis.

Response of Superheated Droplet Detector (SDD) and Bubble Detector (BD) to interrupted irradiations

Energy Technology Data Exchange (ETDEWEB)

Mondal, Prasanna Kumar, E-mail: prasanna_ind_82@yahoo.com; Sarkar, Rupa, E-mail: sarkar_rupa2003@yahoo.com; Chatterjee, Barun Kumar, E-mail: barun_k_chatterjee@yahoo.com

2017-06-11

Superheated droplet detectors (SDD) and bubble detectors (BD) are suspensions of micron-sized superheated liquid droplets in inert medium. The metastable droplets can vaporise upon interaction with ionising radiation generating visible bubbles. In this work, we investigated the response of SDD and BD to interrupted neutron irradiations. We observed that the droplet vaporisation rates for SDD and BD are different in nature. The unusual increase in droplet vaporisation rate observed when the SDD is exposed to neutrons after few minutes of radiation-off period is absent for BD. - Highlights: • Superheated droplet detectors (SDD) and bubble detectors (BD) are suspensions of superheated liquid droplets in inert medium. • The bubble nucleation in superheated droplets can be induced by ionising radiation. • The droplet vaporisation rate for SDD is non-monotonic when it is irradiated periodically to neutrons. • For BD the droplet vaporisation rate decrease monotonically when it is irradiated periodically to neutrons.

The H1 detector

International Nuclear Information System (INIS)

Cozzika, G.

1992-11-01

The H1 detector presently operating at the HERA e-p collider is described. A general overview of the detector is given with particular emphasis on the calorimeters, the main element of which is a liquid Argon calorimeter enclosed within a large radius solenoid. Calorimetry in the proton direction, close to the beam-pipe is provided by a copper-silicon pad hadronic calorimeter. In the electron direction a lead-scintillator electromagnetic calorimeter closes the solid angle between the rear part of the liquid Argon calorimeter and the beam-pipe. An iron limited streamer tube tail catcher using the return yoke of the solenoid as absorber completes the calorimetry of the detector. The hardware triggers derived from the calorimeters are also described and some performance details of the calorimeters are given

Noble Gas Concept Of Operation

Energy Technology Data Exchange (ETDEWEB)

Carrigan, C. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2014-01-20

The intent of this document is to provide the reader with an understanding of a general approach to performing the noble gas component of an On Site Inspection or OSI. The authors of this document recognize that owing to the wide range of scenarios that are possible for carrying out an underground nuclear explosion, the diverse sets of information that might be available to the inspection team initially and the potential range of political and physical constraints imposed during the inspection, a satisfactory prescriptive approach to carrying out the noble gas component of an OSI is unlikely. Rather, the authors intend only to aid the reader in understanding what a reasonable course of actions or responses may be as performed by an inspection team (IT) during a general OSI. If this document helps to inform the intuition of the reader about addressing the challenges resulting from the inevitable deviations from this general scenario, it will have achieved its intent.

A novel method for fission product noble gas sampling

International Nuclear Information System (INIS)

Jain, S.K.; Prakash, Vivek; Singh, G.K.; Vinay, Kr.; Awsthi, A.; Bihari, K.; Joyson, R.; Manu, K.; Gupta, Ashok

2008-01-01

Noble gases occur to some extent in the Earth's atmosphere, but the concentrations of all but argon are exceedingly low. Argon is plentiful, constituting almost 1 % of the air. Fission Product Noble Gases (FPNG) are produced by nuclear fission and large parts of FPNG is produced in Nuclear reactions. FPNG are b-j emitters and contributing significantly in public dose. During normal operation of reactor release of FPNG is negligible but its release increases in case of fuel failure. Xenon, a member of FPNG family helps in identification of fuel failure and its extent in PHWRs. Due to above reasons it becomes necessary to assess the FPNG release during operation of NPPs. Presently used methodology of assessment of FPNG, at almost all power stations is Computer based gamma ray spectrometry. This provides fission product Noble gases nuclide identification through peak search of spectra. The air sample for the same is collected by grab sampling method, which has inherent disadvantages. An alternate method was developed at Rajasthan Atomic Power Station (RAPS) - 3 and 4 for assessment of FPNG, which uses adsorption phenomena for collection of air samples. This report presents details of sampling method for FPNG and noble gases in different systems of Nuclear Power Plant. (author)

CaLIPSO: An novel detector concept for positron annihilation detection

International Nuclear Information System (INIS)

Yvon, D.; Tauzin, G.; Verrecchia, P.; Flouzat, C.; Sharyy, S.; Ramos, E.; Renault, J-Ph.

2013-06-01

The CaLIPSO project focuses on the development of an innovative energetic-photon detector. The detector uses a 'heavy' organometallic liquid: the Trimethyl Bismuth (TMBi), 82% by weight of Bismuth. TMBi efficiently converts through the photo-electric effect photons of energies below 1 MeV. The ionisation signal and light produced in the liquid are both detected. Beyond the measurement of gamma photon energies, this detector will allow locating photon interactions in the detector in three dimensions down to 1 mm 3 and a sub nanosecond timing accuracy. All these desirable properties can be obtained simultaneously with liquid TMBi detector. The optical properties relevant for particle detection are measured. Preliminary results on TMBi ionization properties are shown. (authors)

The Effect of Aqueous Alteration on Primordial Noble Gases in CM Chondrites

Science.gov (United States)

Weimer, D.; Busemann, H.; Alexander, C. M. O'D.; Maden, C.

2017-07-01

We have analyzed 32 CM chondrites for their noble gas contents and isotopic compositions and calculated CRE ages. Correlated effects of parent body aqueous alteration with primordial noble gas contents were detected.

The behavior and effects of the noble metals in the DWPF melter system

International Nuclear Information System (INIS)

Hutson, N.D.; Smith, M.E.

1992-01-01

Fission-product noble metals have caused severe operating problems in numerous worldwide waste vitrification facilities. These dense, highly conductive noble metals have tended to accumulate on the floor of joule-heated glass melters causing electrical distortions which have, in some occurrences, rendered the melter inoperable. A pilot scale vitrification research facility at the U.S. Department of Energy's Savannah River Laboratory has been operated for more than a year with simulated feed streams containing noble metals. In this paper the behavior of these noble metals in the melter system and final glass product and their effects on the scaled DWPF-type melter are discussed

Effective collision frequency of electrons in noble gases

International Nuclear Information System (INIS)

Baille, P.; Chang, J.-S.; Claude, A.; Yau, A.W.; Hobson, R.M.; Ogram, G.L.

1981-01-01

The electron-neutral collision frequency in the noble gases has been calculated using recent numerical results for momentum transfer cross sections by assuming a Maxwellian distribution of electron velocities. In all these gases, except for argon, good agreement is obtained with most previously published experimental and theoretical data. Mean free path, mobilities and diffusion coefficients are also calculated from the resulting effective collision frequencies. The empirical formulae are presented for an electron temperature dependence of the electron-neutral collision frequency for all noble gases up to Tsub(e) < approximately 25.000 K. (author)

Behavior of shut-down dose rate of recirculation piping of BWR under noble metal application

International Nuclear Information System (INIS)

Fuse, Motomasa; Nagase, Makoto; Aizawa, Motohiro; Wada, Yoichi; Ishida, Kazushige; Hosokawa, Hideyuki; Hettiarachchi, Samson; Weber, Christoph

2014-01-01

The cause of shut-down dose rate change of the recirculation piping observed in KKM (Kern Kraftwerk Mühleberg) after application of noble metal injection method is analyzed. The plant experienced the sharp decrease of piping dose rate in the cycle just after the application of noble metal(classic NobleChem TM ) and re-buildup of radioactivity in the subsequent several cycles. After the application of online noble metal injection (online NobleChem TM ), gradual decrease of dose rate has been observed. The presence of a certain amount of noble metal on the iron rich oxide film promotes the dissolution of the oxide under hydrogen addition, resulting in a decrease of deposited noble metal on the oxide film surface as well as of radioactive species in the film. Under the condition of lower amount of noble metal on the surface oxides, the oxidant species, especially hydrogen peroxide, slightly increases facilitating the re-growth of iron rich oxides along with re-buildup of radioactivity. After the application of online noble metal injection during each cycle, gradual dissolution of iron rich oxides and gradual decrease of radioactivity in the oxides proceed to decrease the piping dose rate. In the radioactivity decreasing phase, the presence of zinc is considered to assist the suppression of radioactivity buildup in the oxide film. From the analysis, treating piping surface with platinum after chemical decontamination process is expected to work well for suppression of the piping dose rate. (author)

Optimum filters with time width constraints for liquid argon total-absorption detectors

International Nuclear Information System (INIS)

Gatti, E.; Radeka, V.

1977-10-01

Optimum filter responses are found for triangular current input pulses occurring in liquid argon ionization chambers used as total absorption detectors. The filters considered are subject to the following constraints: finite width of the output pulse having a prescribed ratio to the width of the triangular input current pulse and zero area of a bipolar antisymmetrical pulse or of a three lobe pulse, as required for high event rates. The feasibility of pulse shaping giving an output equal to, or shorter than, the input one is demonstrated. It is shown that the signal-to-noise ratio remains constant for the chamber interelectrode gap which gives an input pulse width (i.e., electron drift time) greater than one third of the required output pulse width

Transverse Position Reconstruction in a Liquid Argon Time Projection Chamber using Principal Component Analysis and Multi-Dimensional Fitting

Science.gov (United States)

Watson, Andrew William

2017-08-01

One of the most enduring questions in modern physics is the dark matter problem. Measurements of galactic rotation curves taken in the middle of the twentieth century suggest that there are large spherical halos of unseen matter permeating and surrounding most galaxies, stretching far beyond their visible extents. Although some of this mass discrepancy can be attributed to sources like primordial black holes or Massive Astrophysical Compact Halo Objects (MACHOs), these theories can only explain a small percentage of this "missing matter". One approach which could account for the entirety of this missing mass is the theory of Weakly Interacting Massive Particles, or "WIMPs". As their name suggests, WIMPs interact only through the weak nuclear force and gravity and are quite massive (100 GeV/c2 to 1 TeV/c2). These particles have very small cross sections ( ≈ 10-39 cm2) with nucleons and therefore interact only very rarely with "normal" baryonic matter. To directly detect a dark matter particle, one needs to overcome this small cross-section barrier. In many experiments, this is achieved by utilizing detectors filled with liquid noble elements, which have excellent particle identification capabilities and are very low-background, allowing potential WIMP signals to be more easily distinguished from detector noise. These experiments also often apply uniform electric fields across their liquid volumes, turning the apparatus into Time Projection Chambers or "TPCs". TPCs can accurately determine the location of an interaction in the liquid volume (often simply called an "event") along the direction of the electric field. In DarkSide-50 ("DS-50" for short), the electric field is aligned antiparallel to the z-axis of the detector, and so the depth of an event can be determined to a considerable degree of accuracy by measuring the time between the first and second scintillation signals ("S1" and "S2"), which are generated at the interaction point itself and in a small gas

Targets Involved in Cardioprotection by the Non-Anesthetic Noble Gas Helium

NARCIS (Netherlands)

Weber, Nina C.; Smit, Kirsten F.; Hollmann, Markus W.; Preckel, Benedikt

2015-01-01

Research data from the past decade indicate that noble gases like xenon and helium exert profound cardioprotection when applied before, during or after organ ischemia. Of all noble gases, especially helium, has gained interest in the past years because it does not have an anesthetic "side effect"

Structural and plasmonic properties of noble metal doped ZnO nanomaterials

Science.gov (United States)

Pathak, Trilok K.; Swart, H. C.; Kroon, R. E.

2018-04-01

Noble metal doped ZnO has been synthesized by the combustion method and the effect of different metals (Ag, Au, Pd) on the structural, morphological, optical, photoluminescence and localized surface plasmon resonance (LSPR) properties has been investigated. X-ray diffraction analysis revealed that the ZnO had a hexagonal wurtzite structure and the crystallite sizes were affected by the doping. The formation of noble metal nanoparticles (NPs) was investigated using transmission electron microscopy and diffuse reflectance spectra. The LSPR of the metallic NPs was predicted using Mie theory calculations. The absorption spectra were calculated using the Kubelka-Munk function and the optical bandgap varied from 3.06 to 3.18 eV for the different doping materials. The experimental results suggest that the origin of enhanced emission was due to direct interaction between the laser photons and the noble material NPs which in turn leads to photoemission transfer of electrons from the noble metals NPs to the conduction band of ZnO.

The Inert and the Noble

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 3. The Inert and the Noble. A G Samuelson. Article-in-a-Box Volume 4 Issue 3 March 1999 pp 3-5 ... Author Affiliations. A G Samuelson1. Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, India.

Scintillators and other particle optical detectors

International Nuclear Information System (INIS)

Chipaux, R.

2011-01-01

The author reports and comments his researcher career in the field of particle optical detectors. He addresses the cases of organic scintillators (scintillating fibers, liquid scintillators), inorganic scintillators (crystals for electromagnetic calorimetry, crystals for solar neutrino spectroscopy), and Cherenkov Effect detectors. He also reports his works on Cd Te detectors and their modelling

Experimental studies and model analysis of noble gas fractionation in porous media

Science.gov (United States)

Ding, Xin; Kennedy, B. Mack.; Evans, William C.; Stonestrom, David A.

2016-01-01

The noble gases, which are chemically inert under normal terrestrial conditions but vary systematically across a wide range of atomic mass and diffusivity, offer a multicomponent approach to investigating gas dynamics in unsaturated soil horizons, including transfer of gas between saturated zones, unsaturated zones, and the atmosphere. To evaluate the degree to which fractionation of noble gases in the presence of an advective–diffusive flux agrees with existing theory, a simple laboratory sand column experiment was conducted. Pure CO2 was injected at the base of the column, providing a series of constant CO2 fluxes through the column. At five fixed sampling depths within the system, samples were collected for CO2 and noble gas analyses, and ambient pressures were measured. Both the advection–diffusion and dusty gas models were used to simulate the behavior of CO2 and noble gases under the experimental conditions, and the simulations were compared with the measured depth-dependent concentration profiles of the gases. Given the relatively high permeability of the sand column (5 ´ 10−11 m2), Knudsen diffusion terms were small, and both the dusty gas model and the advection–diffusion model accurately predicted the concentration profiles of the CO2 and atmospheric noble gases across a range of CO2 flux from ?700 to 10,000 g m−2 d−1. The agreement between predicted and measured gas concentrations demonstrated that, when applied to natural systems, the multi-component capability provided by the noble gases can be exploited to constrain component and total gas fluxes of non-conserved (CO2) and conserved (noble gas) species or attributes of the soil column relevant to gas transport, such as porosity, tortuosity, and gas saturation.

On the methodology of radiochemical neutron activation analysis of noble metals

International Nuclear Information System (INIS)

Chai, C.F.; Ma, S.L.; Mao, X.Y.; Liao, K.N.; Liu, W.C.

1986-01-01

Two different radiochemical procedures were developed: chelate ion resin exchange and amine solvent extraction. Two kinds of new Chinese chelate resins (NANKAI-3926 and BEI-5) and a new long-chain primary amine N 1923 were compared with Srafion NMRR and the tertiary amine N 235 in absorption performance of noble metals, respectively. Influences of various experimental conditions, e.g. sample digestion, acidity, equilibrium time, as well as elution of noble metals, on analytical sensitivity and chemical yield were discussed. Combining with neutron activation, the radiochemical separation procedures developed were used to determine the noble metal contents in the geological samples from Permina/Triassic boundary in South China. (author)

Lunar rock surfaces as detectors of solar processes

International Nuclear Information System (INIS)

Hartung, J.B.; Hunter College, New York, NY)

1980-01-01

Lunar rock surfaces exposed at or just below the lunar surface are considered as detectors of the solar wind, solar flares and solar-derived magnetic fields through their interactions with galactic cosmic rays. The degradation of the solar detector capabilities of lunar surface rocks by meteoroid impact erosion, accreta deposition, loose dust, and sputtering, amorphous layer formation and accelerated diffusion due to solar particles and illumination is discussed, and it is noted that the complex interactions of factors affecting the outer micron of exposed surface material has so far prevented the development of a satisfactory model for a particle detector on the submicron scale. Methods for the determination of surface exposure ages based on the accumulation of light solar wind noble gases, Fe and Mg, impact craters, solar flare tracks, and cosmogenic Kr isotopes are examined, and the systematic variations in the ages determined by the various clocks are discussed. It is concluded that a means of obtaining satisfactory quantitative rate or flux data has not yet been established

Noble Gas Signatures in Groundwater and Rainwater on the Island of Maui, Hawaii - Developing a New Noble Gas Application in Fractured, Volcanic Systems

Science.gov (United States)

Castro, M. C.; Niu, Y.; Warrier, R. B.; Hall, C. M.; Gingerich, S. B.; Scholl, M. A.; Bouvier, L.

2014-12-01

Recent work in the Galapagos Islands suggests that noble gas temperatures (NGTs) in fractured groundwater systems reflect the temperature of the ground surface at the time of infiltration rather than the mean annual air temperature (MAAT) value as commonly assumed in sedimentary systems where NGTs are typically used as indicators of past climate. This suggests that noble gases in fractured areas may record seasonality, and thus, provide information about timing of recharge in addition to location. Calculation of NGTs assumes that rain-derived recharge at the water table is in equilibrium with ground air. Lack of noble gas equilibration with respect to surface conditions, however, was observed in high-altitude springs in the Galapagos Islands and in a rainwater pilot study in Michigan, supporting the NGT seasonality hypothesis. Developing this new NGT application will lead to a better understanding of fractured groundwater flow systems and will contribute to improved water resource management plans. This study, carried out on Maui, Hawaii, is meant to test these hypotheses while improving knowledge of this island's groundwater flow system where limited hydrologic data are available. Here, we present the first results of noble gas analyses from samples collected in springs, groundwater wells and rainwater on northeast Maui. Results show that like most Michigan rainwater samples, rainwater from Maui is in disequilibrium with surface conditions and follows a mass-dependent pattern. Spring samples follow a similar pattern to that of rainwater and suggest that spring water originates directly from rainfall. These findings further support the hypothesis of NGT seasonality. However, while the atmospheric composition of noble gases points to direct supply from rainfall to spring aquifer systems, a direct connection between spring water and deeper aquifer levels or the mantle is apparent from He isotopic ratios which display an almost pure He mantle component in some springs.

Time-dependent behavior of positrons in noble gases

International Nuclear Information System (INIS)

Wadehra, J.M.

1990-01-01

Both equilibrium and nonequilibrium behaviors of positrons in several noble gases are reviewed. Our novel procedure for obtaining the time-dependent behavior of various swarm parameters -- such as the positron drift velocity, average positron energy, positron annihilation rate (or equivalently Z eff ) etc. -- for positrons in pure ambient gases subjected to external electrostatic fields is described. Summaries of time-dependent as well as electric field-dependent results for positron swarms in various noble gases are presented. New time-dependent results for positron swarms in neon are also described in detail. 36 refs., 4 figs., 3 tabs

The prevalent synthesis of one-dimensional noble metal nanostructures based on sulfonated polyaniline at room temperature

International Nuclear Information System (INIS)

Xia Youyi

2011-01-01

We describe a prevalent method of synthesizing one-dimensional (1D) noble metal nanostructures (silver nanobelts and palladium nanowires) by treatment of corresponding noble metal ions only in the presence of the conductive sulfonated polyaniline without using any other reducing agents or energies. The results show that the sulfonated polyaniline provides the dual reductant and “soft template” roles to promoting noble metal ions to form shape-controlled 1D noble metal nanostructures in high yield. The employed approach may also shed some light on the preparation of other noble metal nanostructure by using conductive polymer.

Development of Non-Noble Metal Ni-Based Catalysts for Dehydrogenation of Methylcyclohexane

KAUST Repository

Shaikh Ali, Anaam

2016-01-01

to TOL has only been achieved using the noble Pt-based catalysts. The aim of this study is to develop non-noble, cost-effective metal catalysts that can show excellent catalytic performance, mainly maintaining high TOL selectivity achievable by Pt based

Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xiang; Zhang, Zhenyu [Wuhan University, Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan (China); Liu, Qian; Zheng, Yangheng [University of Chinese Academy of Sciences, School of Physics, Beijing (China); Han, Junbo [Huazhong University of Science and Technology, Wuhan National High Magnetic Field Center, Wuhan (China); Zhang, Xuan; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

2015-11-15

We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments. (orig.)

Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xiang, E-mail: xiangzhou@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Liu, Qian, E-mail: liuqian@ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Han, Junbo [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan (China); Zhang, Zhenyu [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Zhang, Xuan; Ding, Yayun [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China); Zheng, Yangheng [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Zhou, Li; Cao, Jun; Wang, Yifang [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China)

2015-11-21

We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments.

A membrane inlet mass spectrometry system for noble gases at natural abundances in gas and water samples.

Science.gov (United States)

Visser, Ate; Singleton, Michael J; Hillegonds, Darren J; Velsko, Carol A; Moran, Jean E; Esser, Bradley K

2013-11-15

Noble gases dissolved in groundwater can reveal paleotemperatures, recharge conditions, and precise travel times. The collection and analysis of noble gas samples are cumbersome, involving noble gas purification, cryogenic separation and static mass spectrometry. A quicker and more efficient sample analysis method is required for introduced tracer studies and laboratory experiments. A Noble Gas Membrane Inlet Mass Spectrometry (NG-MIMS) system was developed to measure noble gases at natural abundances in gas and water samples. The NG-MIMS system consists of a membrane inlet, a dry-ice water trap, a carbon-dioxide trap, two getters, a gate valve, a turbomolecular pump and a quadrupole mass spectrometer equipped with an electron multiplier. Noble gases isotopes (4)He, (22)Ne, (38)Ar, (84)Kr and (132)Xe are measured every 10 s. The NG-MIMS system can reproduce measurements made on a traditional noble gas mass spectrometer system with precisions of 2%, 8%, 1%, 1% and 3% for He, Ne, Ar, Kr and Xe, respectively. Noble gas concentrations measured in an artificial recharge pond were used to monitor an introduced xenon tracer and to reconstruct temperature variations to within 2 °C. Additional experiments demonstrated the capability to measure noble gases in gas and in water samples, in real time. The NG-MIMS system is capable of providing analyses sufficiently accurate and precise for introduced noble gas tracers at managed aquifer recharge facilities, groundwater fingerprinting based on excess air and noble gas recharge temperature, and field and laboratory studies investigating ebullition and diffusive exchange. Copyright © 2013 John Wiley & Sons, Ltd.

Electromagnetic calorimeter on liquid krypton

International Nuclear Information System (INIS)

Bazzotti, M.; Bianco, G.L.; Lanni, F.; Maggi, B.; Palombo, F.; Sala, A.

1990-01-01

This paper reports on use of noble condensed gases as calorimeter media that is attractive due to the possibility to get not only good energy resolution (like in NaI and CsI calorimeters) but better space resolution for photons. Longitudinal segmentation can provide information for particle identification by dE/dx and also e/π-separation based on longitudinal structure of the shower. The best material for this aim is of course liquid Zenon, but it is impossible to get the necessary amount of it in reasonable time. Therefore, the authors have stopped their choice on the next candidate-liquid Krypton (LKr). Its sufficient amount can be obtained before to the beginning of the experiment

Noble gas separation with the use of inorganic adsorbents

International Nuclear Information System (INIS)

Pence, D.T.; Chou, C.C.; Christian, J.D.; Paplawsky, W.J.

1979-01-01

A noble gas separation process is proposed for application to airborne nuclear fuel reprocessing plant effluents. The process involves the use of inorganic adsorbents for the removal of contaminant gases and noble gas separation through selective adsorption. Water and carbon dioxide are removed with selected zeolites that do not appreciably adsorb the noble gases. Xenon is essentially quantitatively removed with a specially developed adsorbent using conventional adsorption-desorption techniques. Oxygen is removed to low ppM levels by the use of a rapid cycle adsorption technique on a special adsorbent leaving a krypton-nitrogen mixture. Krypton is separated from nitrogen with a special adsorbent operated at about -80 0 C. Because the separation process does not require high pressures and oxygen is readily removed to sufficiently limit ozone formation to insignificant levels, appreciable capital and operating cost savings with this process are possible compared with other proposed processes. In addition, the proposed process is safer to operate

NOBLE - Flexible concept recognition for large-scale biomedical natural language processing.

Science.gov (United States)

Tseytlin, Eugene; Mitchell, Kevin; Legowski, Elizabeth; Corrigan, Julia; Chavan, Girish; Jacobson, Rebecca S

2016-01-14

Natural language processing (NLP) applications are increasingly important in biomedical data analysis, knowledge engineering, and decision support. Concept recognition is an important component task for NLP pipelines, and can be either general-purpose or domain-specific. We describe a novel, flexible, and general-purpose concept recognition component for NLP pipelines, and compare its speed and accuracy against five commonly used alternatives on both a biological and clinical corpus. NOBLE Coder implements a general algorithm for matching terms to concepts from an arbitrary vocabulary set. The system's matching options can be configured individually or in combination to yield specific system behavior for a variety of NLP tasks. The software is open source, freely available, and easily integrated into UIMA or GATE. We benchmarked speed and accuracy of the system against the CRAFT and ShARe corpora as reference standards and compared it to MMTx, MGrep, Concept Mapper, cTAKES Dictionary Lookup Annotator, and cTAKES Fast Dictionary Lookup Annotator. We describe key advantages of the NOBLE Coder system and associated tools, including its greedy algorithm, configurable matching strategies, and multiple terminology input formats. These features provide unique functionality when compared with existing alternatives, including state-of-the-art systems. On two benchmarking tasks, NOBLE's performance exceeded commonly used alternatives, performing almost as well as the most advanced systems. Error analysis revealed differences in error profiles among systems. NOBLE Coder is comparable to other widely used concept recognition systems in terms of accuracy and speed. Advantages of NOBLE Coder include its interactive terminology builder tool, ease of configuration, and adaptability to various domains and tasks. NOBLE provides a term-to-concept matching system suitable for general concept recognition in biomedical NLP pipelines.

The Upgraded D0 detector

Energy Technology Data Exchange (ETDEWEB)

Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, D.L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S.N.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, J.T.; Anderson, S.; /Buenos Aires U. /Rio de Janeiro, CBPF /Sao Paulo, IFT /Alberta U.

2005-07-01

The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

Quality management for noble gas trace analysis; Qualitaetssicherung bei der Edelgasspurenanalyse

Energy Technology Data Exchange (ETDEWEB)

Schmid, S.; Konrad, M.; Kumberg, T.; Schlosser, C. [Bundesamt fuer Strahlenschutz (BfS), Freiburg (Germany); Gohla, H. [Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), Vienna International Centre, Vienna (Austria). Preparatory Commission

2014-01-20

The Federal Office for Radiation Protection operates measurement systems to determine the activity concentrations of Krypton-85 and Xenon-133 in air samples since the early 70s. Certified standards with stable noble gas admixtures are still missing for quality assurance (certified activity concentrations). The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is currently establishing a global noble gas monitoring network for the verification of compliance with the Treaty. In cooperation with CTBTO the BfS currently develops concepts of quality assurance for noble gas measurements. Opportunities for quality assurance without using certified standards are discussed by comparisons between individual laboratories and internal audits. The results from the first CTBTO laboratory intercomparison with synthetic radioxenon samples look very promising.

The DELPHI Detector (DEtector with Lepton Photon and Hadron Identification)

CERN Multimedia

Crawley, B; Munich, K; Mckay, R; Matorras, F; Joram, C; Malychev, V; Behrmann, A; Van dam, P; Drees, J K; Stocchi, A; Adam, W; Booth, P; Bilenki, M; Rosenberg, E I; Morton, G; Rames, J; Hahn, S; Cosme, G; Ventura, L; Marco, J; Tortosa martinez, P; Monge silvestri, R; Moreno, S; Phillips, H; Alekseev, G; Boudinov, E; Martinez rivero, C; Gitarskiy, L; Davenport, M; De clercq, C; Firestone, A; Myagkov, A; Belous, K; Haider, S; Hamilton, K M; Lamsa, J; Rahmani, M H; Malek, A; Hughes, G J; Peralta, L; Carroll, L; Fuster verdu, J A; Cossutti, F; Gorn, L; Yi, J I; Bertrand, D; Myatt, G; Richard, F; Shapkin, M; Hahn, F; Ferrer soria, A; Reinhardt, R; Renton, P; Sekulin, R; Timmermans, J; Baillon, P

2002-01-01

% DELPHI The DELPHI Detector (Detector with Lepton Photon and Hadron Identification) \\\\ \\\\DELPHI is a general purpose detector for physics at LEP on and above the Z$^0$, offering three-dimensional information on curvature and energy deposition with fine spatial granularity as well as identification of leptons and hadrons over most of the solid angle. A superconducting coil provides a 1.2~T solenoidal field of high uniformity. Tracking relies on the silicon vertex detector, the inner detector, the Time Projection Chamber (TPC), the outer detector and forward drift chambers. Electromagnetic showers are measured in the barrel with high granularity by the High Density Projection Chamber (HPC) and in the endcaps by $ 1 ^0 $~x~$ 1 ^0 $ projective towers composed of lead glass as active material and phototriode read-out. Hadron identification is provided mainly by liquid and gas Ring Imaging Counters (RICH). The instrumented magnet yoke serves for hadron calorimetry and as filter for muons, which are identified in t...

Liquid chromatography automatic system with optical activity laser detector and its applications

International Nuclear Information System (INIS)

Fajer, V.; Naranjo, S.; Fernandez, H.; Mora, W.; Cepero, T.; Arista, E.; Mesa, G.; Cossio, G.; Arreche, J.; Fonfria, C.; Rodriguez, C.W.

2009-01-01

A new liquid chromatographic system with polarimetric detection and a computer program allowing the output of chromatograms to a display on line and electronic data storing was designed, built and put to work. The chromatographic system includes the laser polarimetric detector, having a measuring interval of one second, the chromatographic columns, the continuous flux polarimeter tubes of 50 and 100 mm, the programs for data acquisition, processing and storing, and the technical know-how for its most efficiently application. Thirty minutes is all the time needed to obtain a chromatogram by this method which is reasonably shorter than the time required for any other known comparable technique, and offering, besides, lower operation cost. The combination of molecular exclusion liquid chromatography and laser polarimetric detection has turned into a carbohydrate separation and quantification system of basic importance for the evaluation of plants fluids of industrial interest (sugarcane, agave, vegetable extracts, etc.). It is described here the application of this system as an early or complementary indicator of leaf scald -disease that affects sugarcane plants-. Another application on algae extracts gave good results in the separation and identification of biologically active components. The introduction of this system in several research centers in Cuba and abroad has resulted in practical information for the industry. (Author)

Calibration of new measuring systems to detect emissions of radioactive noble gases

International Nuclear Information System (INIS)

Winkelmann, I.; Kreiner, H.J.

1977-12-01

This report describes the calibration of different systems for the integral measurement of radioactive noble gases and the calibration of a measuring chamber for the detection of individual nuclides of radioactive noble gases in the gaseous effluent of nuclear power plants. For these measuring chambers the calibration factors for Kr-85 and Xe-133 are given as well as the detection limits to be obtained with these measuring systems for several radioactive noble gases present in the gaseous effluent at the stack of nuclear power plants. Calibration factors for Kr-85 and Xe-133 and the detection limits of this measuring method for the detections of individual nuclides of radioactive noble gases in air samples are defined taken wirh a high pressure compressor in pressure flasks an measured on a Ge(Li)-semiconductor spectrometer (pressure flask measuring method). A measuring equipment is described and calibrated which allows simultaneous measurement of activity concentration of radioactive noble gases and radioactive aerosols with a sensitivity of 2 x 10 -7 Ci/m 3 for radioactive gases and 1 x 10 -9 Ci/m 3 for radioactive particulates at a background radiation of 1 R/h. This paper is an additional report to our STH-Bericht 3/76, 'Calibration of measuring equipment for monitoring of gaseous effluents from nuclear power plants', which specifies a procedure for the calibration of measuring chambers for monitoring of gaseous radioactive effluents from nuclear power plants /1/. The calibration system used here makes it possible to simultaneously calibrate several noble gas measuring devices. (orig.) [de

Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

Science.gov (United States)

Ray, Siba P.; Liu, Xinghua

2000-01-01

An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

Performance of BEGe detectors for GERDA Phase II

Energy Technology Data Exchange (ETDEWEB)

Lazzaro, Andrea [Physik-Department E15, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration

2015-07-01

After the end of the data-taking for GERDA Phase I, the apparatus has been upgraded to fulfill the requirements of the second phase. Phase II sensitivity will be driven by 30 custom made BEGe detectors. This detectors are now available and can be operated in phaseII configuration in the GERDA cryostat together with the liquid argon scintillation veto. The performances of BEGe detectors in liquid argon are presented in this talk. Besides the spectroscopy capability, the focus will be placed on the expectations in terms of background rejection via pulse shape discrimination (PSD). In particular the main goal the BEGe's pulse shape analysis is to discriminate surface events produced by beta emitters (e.g. {sup 42}K) present in the liquid Ar.

Microfluidic Scintillation Detectors

CERN Multimedia

Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

A rope-net support system for the liquid scintillator detector for the SNO+ experiment

Energy Technology Data Exchange (ETDEWEB)

Bialek, A., E-mail: abialek@snolab.ca [University of Alberta, Edmonton (Canada); Chen, M. [Queen' s University, Kingston (Canada); Cleveland, B. [SNOLAB, Lively (Canada); Gorel, P.; Hallin, A. [University of Alberta, Edmonton (Canada); Harvey, P.J.; Heise, J. [Queen' s University, Kingston (Canada); Kraus, C. [Laurentian University, Sudbury (Canada); Krauss, C.B. [University of Alberta, Edmonton (Canada); Lawson, I. [SNOLAB, Lively (Canada); Ng, C.J.; Pinkney, B. [University of Alberta, Edmonton (Canada); Rogowsky, D.M. [Rogowsky Engineering Ltd, AECOM Canada Ltd (Canada); Sibley, L.; Soluk, R.; Soukup, J. [University of Alberta, Edmonton (Canada); Vázquez-Jáuregui, E. [SNOLAB, Lively (Canada); Laurentian University, Sudbury (Canada)

2016-08-11

The detector for the SNO+ experiment consists of 780 000 kg of liquid scintillator contained in an acrylic vessel that is surrounded by water. A mechanical system has been installed to counteract the 1.25 MN of buoyant force on the acrylic and prevent the vessel from moving. The system is a rope net, designed using a Finite Element Analysis to calculate the amount of stress on the acrylic induced by the ropes, hydrostatic pressures and gravity. A dedicated test was performed to measure strains in the acrylic arising from the complex geometry of the knots in the rope system. The ratio between measured and FEA calculated strains was 1.3.

A new digital method for high precision neutron-gamma discrimination with liquid scintillation detectors

International Nuclear Information System (INIS)

Nakhostin, M

2013-01-01

A new pulse-shape discrimination algorithm for neutron and gamma (n/γ) discrimination with liquid scintillation detectors has been developed, leading to a considerable improvement of n/γ separation quality. The method is based on triangular pulse shaping which offers a high sensitivity to the shape of input pulses, as well as, excellent noise filtering characteristics. A clear separation of neutrons and γ-rays down to a scintillation light yield of about 65 keVee (electron equivalent energy) with a dynamic range of 45:1 was achieved. The method can potentially operate at high counting rates and is well suited for real-time measurements.

Liquid chromatography detection unit, system, and method

Science.gov (United States)

Derenzo, Stephen E.; Moses, William W.

2015-10-27

An embodiment of a liquid chromatography detection unit includes a fluid channel and a radiation detector. The radiation detector is operable to image a distribution of a radiolabeled compound as the distribution travels along the fluid channel. An embodiment of a liquid chromatography system includes an injector, a separation column, and a radiation detector. The injector is operable to inject a sample that includes a radiolabeled compound into a solvent stream. The position sensitive radiation detector is operable to image a distribution of the radiolabeled compound as the distribution travels along a fluid channel. An embodiment of a method of liquid chromatography includes injecting a sample that comprises radiolabeled compounds into a solvent. The radiolabeled compounds are then separated. A position sensitive radiation detector is employed to image distributions of the radiolabeled compounds as the radiolabeled compounds travel along a fluid channel.

Possible solar noble-gas component in Hawaiian basalts

Energy Technology Data Exchange (ETDEWEB)

Honda, Masahiko; McDougall, I.; Patterson, D.B.; Doulgeris, A. (Australian National Univ., Canberra (Australia). Research School of Earth Sciences); Clague, D.A. (Geological Survey, Menlo Park, CA (USA))

1991-01-10

The noble-gas elemental and isotopic composition in the Earth is significantly different from that of the present atmosphere, and provides an important clue to the origin and history of the Earth and its atmosphere. Possible candidates for the noble-gas composition of the primordial Earth include a solar-like component, a planetary-like component (as observed in primitive meteorites) and a component similar in composition to the present atmosphere. In an attempt to identify the contributions of such components, we have measured isotope ratios of helium and neon in fresh basaltic glasses dredged from Loihi seamount and the East Rift Zone of Kilauea. We find a systematic enrichment in {sup 20}Ne and {sup 21}Ne relative to {sup 22}Ne, compared with atmospheric neon. The helium and neon isotope signatures observed in our samples can be explained by mixing of solar, present atmospheric, radiogenic and nucleogenic components. These data suggest that the noble-gas isotopic composition of the mantle source of the Hawaiian plume is different from that of the present atmosphere, and that it includes a significant solar-like component. We infer that this component was acquired during the formation of the Earth. (author).

Method of processing radioactive liquid wastes

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, Y; Kikuchi, M; Funabashi, K; Yusa, H; Horiuchi, S

1978-12-21

Purpose: To decrease the volume of radioactive liquid wastes essentially consisting of sodium hydroxide and boric acid. Method: The concentration ratio of sodium hydroxide to boric acid by weight in radioactive liquid wastes essentially consisting of sodium hydroxide and boric acid is adjusted in the range of 0.28 - 0.4 by means of a pH detector and a sodium concentration detector. Thereafter, the radioactive liquid wastes are dried into powder and then discharged.

Investigation of n{sup +} surface events in HPGe detectors for liquid argon background rejection in GERDA

Energy Technology Data Exchange (ETDEWEB)

Lehnert, Bjoern [TU-Dresden, Dresden (Germany); Collaboration: GERDA-Collaboration

2015-07-01

The GERDA experiment is searching for neutrinoless double beta decay (0νββ) in {sup 76}Ge using an array of germanium detectors immersed in liquid argon (LAr). Phase II of the experiment aims to improve the background level by a factor 10 in order to reach 10{sup -3} counts / (kg.keV.yr). A strong suppression technique is required to suppress the intrinsic LAr background of {sup 42}Ar/{sup 42}K. 30 newly produced p-type Broad Energy Germanium (BEGe) detectors will be deployed in Phase II. The n{sup +} electrode of the GERDA BEGe detectors is covering 96-98 % of the surface and is between 0.5 and 1.2 mm thick. Betas from the {sup 42}K decay can penetrated the detector surface and deposit energies within the 0νββ region. Experiences from GERDA Phase I show that these surface events are the dominate background component without suppression. Energy depositions inside the n{sup +} layer create pulse shapes that are slower than those from interactions in the bulk. This talk presents a rejection technique for those events. The signal development inside the n{sup +} layer is modeled and applied in Geant4 Monte Carlo simulations. The simulations are compared with data for {sup 241}Am and {sup 90}Sr calibration source measurements. The suppression capabilities are extrapolated for {sup 42}K in GERDA Phase II.

Isotopic mass-dependence of noble gas diffusion coefficients inwater

Energy Technology Data Exchange (ETDEWEB)

Bourg, I.C.; Sposito, G.

2007-06-25

Noble gas isotopes are used extensively as tracers inhydrologic and paleoclimatic studies. These applications requireknowledge of the isotopic mass (m) dependence of noble gas diffusioncoefficients in water (D), which has not been measured but is estimatedusing experimental D-values for the major isotopes along with an untestedrelationship from kinetic theory, D prop m-0.5. We applied moleculardynamics methods to determine the mass dependence of D for four noblegases at 298 K, finding that D prop m-beta with beta<0.2, whichrefutes the kinetic theory model underlying all currentapplications.

Highly stable noble-metal nanoparticles in tetraalkylphosphonium ionic liquids for in situ catalysis.

Science.gov (United States)

Banerjee, Abhinandan; Theron, Robin; Scott, Robert W J

2012-01-09

Gold and palladium nanoparticles were prepared by lithium borohydride reduction of the metal salt precursors in tetraalkylphosphonium halide ionic liquids in the absence of any organic solvents or external nanoparticle stabilizers. These colloidal suspensions remained stable and showed no nanoparticle agglomeration over many months. A combination of electrostatic interactions between the coordinatively unsaturated metal nanoparticle surface and the ionic-liquid anions, bolstered by steric protection offered by the bulky alkylated phosphonium cations, is likely to be the reason behind such stabilization. The halide anion strongly absorbs to the nanoparticle surface, leading to exceptional nanoparticle stability in halide ionic liquids; other tetraalkylphosphonium ionic liquids with non-coordinating anions, such as tosylate and hexafluorophosphate, show considerably lower affinities towards the stabilization of nanoparticles. Palladium nanoparticles stabilized in the tetraalkylphosphonium halide ionic liquid were stable, efficient, and recyclable catalysts for a variety of hydrogenation reactions at ambient pressures with sustained activity. Aerial oxidation of the metal nanoparticles occurred over time and was readily reversed by re-reduction of oxidized metal salts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Noble Gas Release Signal as a Precursor to Fracture

Science.gov (United States)

Bauer, S. J.; Lee, H.; Gardner, W. P.

2017-12-01

We present empirical results of rock strain, microfracturing, acoustic emissions, and noble gas release from laboratory triaxial experiments for a granite, basalt, shale and bedded rock salt. Noble gases are released and measured real-time during deformation using mass spectrometry. The gas release represents a precursive signal to macrofracture. Gas release is associated with increased acoustic emissions indicating that microfracturing is required to release gas and create pathways for the gas to be sensed. The gas released depends on initial gas content, pore structure and its evolution during deformation, the deformation amount, matrix permeability, deformation style and the stress/strain history. Gases are released from inter and intracrystalline sites; release rate increases as strain and microfracturing increases. The gas composition depends on lithology, geologic history and age, fluids present, and radioisotope concentrations that affect radiogenic noble gas isotope (e.g. 4He,40Ar) production. Noble gas emission and its relationship to crustal processes such as seismicity and volcanism, tectonic velocities, qualitative estimates of deep permeability, age dating of groundwater, and a signature of nuclear weapon detonation. Our result show that mechanical deformation of crustal materials is an important process controlling gas release from rocks and minerals, and should be considered in techniques which utilize gas release and/or accumulation. We propose using noble gas release to signal rock deformation in boreholes, mines and waste repositories. We postulate each rock exhibits a gas release signature which is microstructure, stress, strain, and/or permanent deformation dependent. Calibration of such relationships, for example relating gas release per rock unit volume to strain may be used to quantify rock deformation and develop predictive models.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and

Determination of Imidacloprid and metabolites by liquid chromatography with an electrochemical detector and post column photochemical reactor

Energy Technology Data Exchange (ETDEWEB)

Rancan, M. [Consiglio per la Ricerca e la Sperimentazione in Agricoltura (CRA), Istituto Nazionale di Apicoltura, Via di Saliceto 80, I-40128 Bologna (Italy)]. E-mail: mrancan@inapicoltura.org; Sabatini, A.G. [Consiglio per la Ricerca e la Sperimentazione in Agricoltura (CRA), Istituto Nazionale di Apicoltura, Via di Saliceto 80, I-40128 Bologna (Italy); Achilli, G. [Euroservice s.r.l., Piazza Maggiolini 3A, I-20015 Parabiago, Milan (Italy); Galletti, G.C. [Dipartimento di Chimica ' G.Ciamician' , University of Bologna, Via F. Selmi 2, I-40126 Bologna (Italy)

2006-01-05

A procedure for the determination of Imidacloprid and its main metabolites was set up by means of liquid chromatography with an electrochemical detector and post-column photochemical reactor (LC-h{nu}-ED). Sample clean-up was developed for bees, filter paper and maize leaves. Chromatographic conditions were based on a reversed-phase C-18 column operated by phosphate buffer 50 mM/CH{sub 3}CN (80/20, v/v) at pH 2.9. Detection of Imidacloprid and its metabolites was performed at a potential of 800 mV after photoactivation at 254 nm. Compared to conventional techniques such as gas chromatography/mass spectrometry (GC/MS) or LC coupled to other detectors, the present method allows simultaneous trace-level determination of both Imidacloprid (0.6 ng ml{sup -1}) and its main metabolites (2.4 ng ml{sup -1})

Determination of Imidacloprid and metabolites by liquid chromatography with an electrochemical detector and post column photochemical reactor

International Nuclear Information System (INIS)

Rancan, M.; Sabatini, A.G.; Achilli, G.; Galletti, G.C.

2006-01-01

A procedure for the determination of Imidacloprid and its main metabolites was set up by means of liquid chromatography with an electrochemical detector and post-column photochemical reactor (LC-hν-ED). Sample clean-up was developed for bees, filter paper and maize leaves. Chromatographic conditions were based on a reversed-phase C-18 column operated by phosphate buffer 50 mM/CH 3 CN (80/20, v/v) at pH 2.9. Detection of Imidacloprid and its metabolites was performed at a potential of 800 mV after photoactivation at 254 nm. Compared to conventional techniques such as gas chromatography/mass spectrometry (GC/MS) or LC coupled to other detectors, the present method allows simultaneous trace-level determination of both Imidacloprid (0.6 ng ml -1 ) and its main metabolites (2.4 ng ml -1 )

Reflectance dependence of polytetrafluoroethylene on thickness for xenon scintillation light

Energy Technology Data Exchange (ETDEWEB)

Haefner, J.; Neff, A.; Arthurs, M.; Batista, E.; Morton, D.; Okunawo, M.; Pushkin, K.; Sander, A. [Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Stephenson, S. [Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); University of California Davis, Department of Physics, One Shields Ave., Davis, CA 95616 (United States); Wang, Y. [Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States); Lorenzon, W., E-mail: lorenzon@umich.edu [Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1040 (United States)

2017-06-01

Many rare event searches including dark matter direct detection and neutrinoless double beta decay experiments take advantage of the high VUV reflective surfaces made from polytetrafluoroethylene (PTFE) reflector materials to achieve high light collection efficiency in their detectors. As the detectors have grown in size over the past decade, there has also been an increased need for ever thinner detector walls without significant loss in reflectance to reduce dead volumes around active noble liquids, outgassing, and potential backgrounds. We report on the experimental results to measure the dependence of the reflectance on thickness of two PTFE samples at wavelengths near 178 nm. No change in reflectance was observed as the wall thickness of a cylindrically shaped PTFE vessel immersed in liquid xenon was varied between 1 mm to 9.5 mm.

Liquid argon as an electron/photon detector in the energy range of 50 MeV to 2 GeV: a Monte Carlo investigation

International Nuclear Information System (INIS)

Goodman, M.S.; Denis, G.; Hall, M.; Karpovsky, A.; Wilson, R.; Gabriel, T.A.; Bishop, B.L.

1980-12-01

Monte Carlo techniques which have been used to study the characteristics of a proposed electron/photon detector based on the total absorption of electromagnetic showers in liquid argon have been investigated. The energy range studied was 50 MeV to 2 GeV. Results are presented on the energy and angular resolution predicted for the device, along with the detailed predictions of the transverse and longitudinal shower distributions. Comparisons are made with other photon detectors, and possible applications are discussed

Noble gas control room accident filtration system for severe accident conditions (N-CRAFT)

International Nuclear Information System (INIS)

Hill, Axel; Stiepani, Cristoph; Drechsler, Michael

2015-01-01

Severe accidents might cause the release of airborne radioactive substances to the environment of the NPP either due to containment leakages or due to intentional filtered containment venting. In the latter case aerosols and iodine are retained, however noble gases are not retainable by the FCVS or by conventional air filtration systems like HEPA filters and iodine absorbers. Radioactive noble gases nevertheless dominate the activity release depending on the venting procedure and the weather conditions. To prevent unacceptable contamination of the control room atmosphere by noble gases, AREVA GmbH has developed a noble gas control room accident filtration system (CRAFT) which can supply purified fresh air to the control room without time limitation. The retention process is based on dynamic adsorption of noble gases on activated carbon. The system consists of delay lines (carbon columns) which are operated by a continuous and simultaneous adsorption and desorption process. CRAFT allows minimization of the dose rate inside the control room and ensures low radiation exposure to the staff by maintaining the control room environment suitable for prolonged occupancy throughout the duration of the accident. CRAFT consists of a proven modular design either transportable or permanently installed. (author)

Noble gas enrichment studies at JET

International Nuclear Information System (INIS)

Groth, M.; Andrew, P.; Fundamenski, W.; Guo, H.Y.; Hillis, D.L.; Hogan, J.T.; Horton, L.D.; Matthews, G.F.; Meigs, A.G.; Morgan, P.M.; Stamp, M.F.; Hellermann, M. von

2001-01-01

Adequate helium exhaust has been achieved in reactor-relevant ELMy H-mode plasmas in JET performed in the MKII AP and MKII GB divertor geometry. The divertor-characteristic quantities of noble gas compression and enrichment have been experimentally inferred from Charge Exchange Recombination Spectroscopy measurements in the core plasma, and from spectroscopic analysis of a Penning gauge discharge in the exhaust gas. The retention of helium was found to be satisfactory for a next-step device, with enrichment factors exceeding 0.1. The helium enrichment decreases with increasing core plasma density, while the neon enrichment has the opposite behaviour. Analytic and numerical analyses of these plasmas using the divertor impurity code package DIVIMP/NIMBUS support the explanation that the enrichment of noble gases depends significantly on the penetration depth of the impurity neutrals with respect to the fuel atoms. Changes of the divertor plasma configuration and divertor geometry have no effect on the enrichment

Probing the interaction of noble gases with pristine and nitrogen-doped graphene through Raman spectroscopy

Science.gov (United States)

Cunha, Renato; Perea-López, Néstor; Elías, Ana Laura; Fujisawa, Kazunori; Carozo, Victor; Feng, Simin; Lv, Ruitao; dos Santos, Maria Cristina; Terrones, Mauricio; Araujo, Paulo T.

2018-05-01

The interactions of adsorbates with graphene have received increasing attention due to its importance in the development of applications involving graphene-based coatings. Here, we present a study of the adsorption of noble gases on pristine and nitrogen-doped graphene. Single-layer graphene samples were synthesized by chemical vapor deposition (CVD) and transferred to transmission electron microscopy (TEM) grids. Several noble gases were allowed to adsorb on the suspended graphene substrate at very low temperatures. Raman spectra show distinct frequency blue shifts in both the 2D and G bands, which are induced by gas adsorption onto high quality single layer graphene (1LG). These shifts, which we associate with compressive biaxial strain in the graphene layers induced by the noble gases, are negligible for nitrogen-doped graphene. Additionally, a thermal depinning transition, which is related to the desorption of a noble gas layer from the graphene surface at low temperatures (ranging from 20 to 35 K), was also observed at different transition temperatures for different noble gases. These transition temperatures were found to be 25 K for argon and 35 K for xenon. Moreover, we were able to obtain values for the compressive biaxial strain in graphene induced by the adsorbed layer of noble gases, using Raman spectroscopy. Ab initio calculations confirmed the correlation between the noble gas-induced strain and the changes in the Raman features observed.

Polarization of stable and radioactive noble gas nuclei by spin exchange with laser pumped alkali atoms

International Nuclear Information System (INIS)

Calaprice, F.; Happer, W.; Schreiber, D.

1984-01-01

The nuclei of noble gases can be strongly polarized by spin exchange with sufficiently dense optically pumped alkali vapors. Only a small fraction of the spin angular momentum of the alkali atoms is transferred to the nuclear spin of the noble gas. Most of the spin angular momentum is lost to translational angular momentum of the alkali and noble gas atoms about each other. For heavy noble gases most of the angular momentum transfer occurs in alkali-noble-gas van der Waals molecules. The transfer efficiency depends on the formation and breakup rates of the van der Waals molecules in the ambient gas. Experimental methods to measure the spin transfer efficiencies have been developed. Nuclei of radioactive noble gases have been polarized by these methods, and the polarization has been detected by observing the anisotropy of the radioactive decay products. Very precise measurements of the magnetic moments of the radioactive nuclei have been made. 12 references, 9 figures

Neutron and photon spectrometry with liquid scintillation detectors in mixed fields

CERN Document Server

Klein, H

2002-01-01

Liquid scintillation detectors of type NE213 or BC501A are well suited and routinely used for spectrometry in mixed n-gamma-fields. Neutron- and photon-induced pulse height spectra may be simultaneously recorded making use of the n/gamma-discrimination capability based on pulse shape analysis. The light output functions for the detected secondary charged particles, i.e. electrons, positrons, protons and other charged reaction products, and the pulse height resolution function must carefully be determined. This can be done experimentally, in part via an iterative procedure by comparison with calculations. The response functions can then be reliably calculated by Monte Carlo simulations. Photon response functions calculated with the PHRESP code, which was developed on the basis of the EGS4+PRESTA program package, are in very good agreement with calibrations up to 17 MeV, both in shape and absolute scale. Similarly, neutron response functions calculated with the NRESP7 code well describe the pulse height spectra...

Capillary detectors

International Nuclear Information System (INIS)

Konijn, J.; Winter, K.; Vilain, P.; Wilquet, G.; Fabre, J.P.; Kozarenko, E.; Kreslo, I.; Goldberg, J.; Hoepfner, K.; Bay, A.; Currat, C.; Koppenburg, P.; Frekers, D.; Wolff, T.; Buontempo, S.; Ereditato, A.; Frenkel, A.; Liberti, B.; Martellotti, G.; Penso, G.; Ekimov, A.; Golovkin, S.; Govorun, V.; Medvedkov, A.; Vasil'chenko, V.

1998-01-01

The option for a microvertex detector using glass capillary arrays filled with liquid scintillator is presented. The status of capillary layers development and possible read-out techniques for high rate environment are reported. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Column Liquid Chromatography.

Science.gov (United States)

Majors, Ronald E.; And Others

1984-01-01

Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

Near transferable phenomenological n-body potentials for noble metals.

Science.gov (United States)

Pontikis, Vassilis; Baldinozzi, Gianguido; Luneville, Laurence; Simeone, David

2017-09-06

We present a semi-empirical model of cohesion in noble metals with suitable parameters reproducing a selected set of experimental properties of perfect and defective lattices in noble metals. It consists of two short-range, n-body terms accounting respectively for attractive and repulsive interactions, the former deriving from the second moment approximation of the tight-binding scheme and the latter from the gas approximation of the kinetic energy of electrons. The stability of the face centred cubic versus the hexagonal compact stacking is obtained via a long-range, pairwise function of customary use with ionic pseudo-potentials. Lattice dynamics, molecular statics, molecular dynamics and nudged elastic band calculations show that, unlike previous potentials, this cohesion model reproduces and predicts quite accurately thermodynamic properties in noble metals. In particular, computed surface energies, largely underestimated by existing empirical cohesion models, compare favourably with measured values, whereas predicted unstable stacking-fault energy profiles fit almost perfectly ab initio evaluations from the literature. All together the results suggest that this semi-empirical model is nearly transferable.

Lithium germanium detectors reactivation

International Nuclear Information System (INIS)

Nicolai, J.A.; Marti, G.V.; Riso, J.M.; Gimenez, C.R.

1981-01-01

A convenient method to regenerate the characteristics of damaged Ge(li) detectors, that has been applied in the authors' laboratory, is described. The procedure consists in warming-up the crystal in its cryostat to temperatures between 10 deg C and 30 deg C above room temperature, in order to clean its surface. Subsequent cooling down to liquid nitrogen temperature, followed by one or more clean-up drifting processes, are applied to the crystals. This paper summarizes the results obtained with several detectors; this method was applied successfully to 15 detectors more. (author) [es

Experience from operating germanium detectors in GERDA

Science.gov (United States)

Palioselitis, Dimitrios; GERDA Collaboration

2015-05-01

Phase I of the Germanium Detector Array (GERDA) experiment, searching for the neutrinoless double beta (0νββ) decay of 76Ge, was completed in September 2013. The most competitive half-life lower limit for the 0νββ decay of 76Ge was set (T-0ν1/2 > 2.1 · 1025 yr at 90% C.L.). GERDA operates bare Ge diodes immersed in liquid argon. During Phase I, mainly refurbished semi-coaxial high purity Ge detectors from previous experiments were used. The experience gained with handling and operating bare Ge diodes in liquid argon, as well as the stability and performance of the detectors during GERDA Phase I are presented. Thirty additional new enriched BEGe-type detectors were produced and will be used in Phase II. A subgroup of these detectors has already been used successfully in GERDA Phase I. The present paper gives an overview of the production chain of the new germanium detectors, the steps taken to minimise the exposure to cosmic radiation during manufacturing, and the first results of characterisation measurements in vacuum cryostats.

Analysis of the physical atomic forces between noble gas atoms, alkali ions and halogen ions

Science.gov (United States)

Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

1986-01-01

The physical forces between atoms and molecules are important in a number of processes of practical importance, including line broadening in radiative processes, gas and crystal properties, adhesion, and thin films. The components of the physical forces between noble gas atoms, alkali ions, and halogen ions are analyzed and a data base for the dispersion forces is developed from the literature based on evaluations with the harmonic oscillator dispersion model for higher order coefficients. The Zener model of the repulsive core is used in the context of the recent asymptotic wave functions of Handler and Smith; and an effective ionization potential within the Handler and Smith wave functions is defined to analyze the two body potential data of Waldman and Gordon, the alkali-halide molecular data, and the noble gas crystal and salt crystal data. A satisfactory global fit to this molecular and crystal data is then reproduced by the model to within several percent. Surface potentials are evaluated for noble gas atoms on noble gas and salt crystal surfaces with surface tension neglected. Within this context, the noble gas surface potentials on noble gas and salt crystals are considered to be accurate to within several percent.

Helium Isotopes and Noble Gas Abundances of Cave Dripping Water in Three Caves in East Asia

Science.gov (United States)

Chen, A. T.; Shen, C. C.; Tan, M.; Li, T.; Uemura, R.; Asami, R.

2015-12-01

Paleo-temperature recorded in nature archives is a critical parameter to understand climate change in the past. With advantages of unique inert chemical characteristics and sensitive solubilities with temperature, dissolved noble gases in speleothem inclusion water were recently proposed to retrieve terrestrial temperature history. In order to accurately apply this newly-developed speleothem noble gas temperature (NGT) as a reliable proxy, a fundamental issue about behaviors of noble gases in the karst should be first clarified. In this study, we measured noble gas contents in air and dripping water to evaluate any ratio deviation between noble gases. Cave dripping water samples was collected from three selected caves, Shihua Cave in northern China, Furong Cave in southwestern, and Gyukusen Cave in an island located in the western Pacific. For these caves are characterized by a thorough mixing and long-term storage of waters in a karst aquifer by the absence of seasonal oxygen isotope shifts. Ratios of dripping water noble gases are statistically insignificant from air data. Helium isotopic ratios in the dripping water samples match air value. The results indicate that elemental and isotopic signatures of noble gases from air can be frankly preserved in the epikarst and support the fidelity of NGT techniques.

The predicted effectiveness of noble metal treatment at the Chinshan boiling water reactor

International Nuclear Information System (INIS)

Yeh Tsungkuang; Chu Fang; Chang Ching; Huang Chiashen

2000-01-01

The technique of noble metal treatment (NMT) available in a form of noble metal cooling (NMC) or noble metal chemical addition (NMCA), was introduced to enhance effectiveness of hydrogen water chemistry. Since it is technically difficult to gain access to an entire primary heat transport circuit (PHTC) of a BWR and monitor variation on electrochemical corrosion potential (ECP), a question whether the NMC technology is indeed effective for lowering the ECP of every location in a BWR is not still well understood at the moment. Then, computer modeling is so far the best tool to help investigate effectiveness of the NMT along PHCT of the BWR. Here was discussed on how the computer model was calibrated by using measured chemistry data obtained from No. 2 unit (BWR) in the Kuosheng Plant. The effect of noble metal treatment coupled with hydrogen water chemistry has been quantitatively molded, on a base of two different sets of ECD enhancement data. It was predicted that No. 1 unit in the Chinshan could be protected by noble metal treatment with lower [H 2 ] FW . In the case of competitive enhancing factors for the ECDs of oxygen reduction, hydrogen peroxide reduction, and hydrogen oxidation reactions, HWC had always to be present for noble metal treatment to be effective for protecting a reactor. Otherwise, according to a model calculation based upon the results from Kim's work, the ECP might instead be increased due to the enhanced reduction reaction rate of oxygen and hydrogen peroxide, especially in the near core regions. (G.K.)

Oxidation behaviour of noble-metal inclusions in used UO2 nuclear fuel

International Nuclear Information System (INIS)

McEachern, R.

1997-07-01

The literature on the chemistry of the noble-metal (Mo-Rh-Ru-Pd-Tc) inclusions found in used nuclear fuel has been reviewed. The Mo-Ru-Pd phase diagram is reasonably well understood, and the pseudoternary Mo-(Tc+Ru)-Rh+Pd) system can be used to qualitatively understand the phase chemistry of the noble-metal inclusions. The kinetics of the oxidation reaction are not particularly well understood, but they are of limited applicability to understanding the properties of used fuel. In contrast, it is important to determine the thermodynamic activity of molybdenum in noble-metal inclusions, so that analysis of their molybdenum content can be used as a probe of the local oxygen potential of the used fuel. (author)

The interpretation of ellipsometric measurements of ion bombardment of noble gases on semiconductor surfaces

NARCIS (Netherlands)

Holtslag, A.H.M.; Slager, U.C.; van Silfhout, Arend

1985-01-01

Low energy noble gas ion bombardment and thermal desorption studies were carried out on Si(111) and analysed, in situ, using spectroscopic ellipsometry. The amorphous layer thickness and implanted noble gas fraction were calculated.

Demonstration of Key Elements of a Dual Phase Argon Detection System Suitable for Measurement of Coherent Neutrino-Nucleus Scattering

International Nuclear Information System (INIS)

Adam, B; Celeste, W; Christian, H; Wolfgang, S; Norman, M

2007-01-01

This feasibility study sought to demonstrate several necessary steps in a research program whose ultimate goal is to detect coherent scattering of reactor antineutrinos in dual-phase noble liquid detectors. By constructing and operating a Argon gas-phase drift and scintillation test-bed, the study confirmed important expectations about sensitivity of these detectors, and thereby met the goals set forth in our original proposal. This work has resulted in a successful Lab-Wide LDRD for design and deployment of a coherent scatter detector at a nuclear reactor, and strong interest by DOE Office of Science. In recent years, researchers at LLNL and elsewhere have converged on a design approach for a new generation of very low noise, low background particle detectors known as two-phase noble liquid/noble gas ionization detectors. This versatile class of detector can be used to detect coherent neutrino scattering-an as yet unmeasured prediction of the Standard Model of particle physics. Using the dual phase technology, our group would be the first to verify the existence of this process. Its (non)detection would (refute)validate central tenets of the Standard Model. The existence of this process is also important in astrophysics, where coherent neutrino scattering is assumed to play an important role in energy transport within nascent neutron stars. The potential scientific impact after discovery of coherent neutrino-nuclear scattering is large. This phenomenon is flavor-blind (equal cross-sections of interaction for all three neutrino types), raising the possibility that coherent scatter detectors could be used as total flux monitors in future neutrino oscillation experiments. Such a detector could also be used to measure the flavor-blind neutrino spectrum from the next nearby (d ∼ 10kpc) type Ia supernova explosion. The predicted number of events [integrated over explosion time] for a proposed dual-phase argon coherent neutrino scattering detector is 10000 nuclear

Calibration method of liquid zone controller using the ex-core detector signal of CANDU 6 reactor

International Nuclear Information System (INIS)

Park, D.H.; Lee, E.K.; Shin, H.C.; Bae, S.M.; Hong, S.Y.

2013-01-01

Highlights: ► We developed a new LZC calibration method and measurement system. ► Photo-neutron effect, reactor core size, and detector position were evaluated and tested. ► We applied the new method and system to Wolsong NPP Unit 1. ► The LZC calibration test was well completed, and the requirement of the test was satisfied. - Abstract: The Phase-B test (low-power reactor physics test) is one of the commissioning tests for Canada Deuterium Uranium (CANDU) reactors that ensures the safe and reliable operation of the core during the design lifetime. The Phase-B test, which includes the approach to the first criticality at low reactor powers, is performed to verify the feasibility of the reactor’s physics design and to ensure the integrity of the control and protection facilities. The commissioning testing of pressurized heavy water moderated reactors (PHWRs) is usually performed only once (at the initial commissioning after construction). The large-scale facilities of the Wolsong nuclear power plant (NPP) Unit 1 have been gradually improved since May 2009 to extend its lifetime. The refurbishment was completed in April 2011 – then this NPP has been in operation again. We discusses the new methodology and measurement system that uses an ex-core detector signal for liquid zone controller (LZC) calibration of the Phase-B test instead of conventional methods. The inverse kinetic equation in the reactivity calculator is modified to treat the 17 delayed neutron groups including 11 photo-neutron fractions. The signal acquisition resolution of the reactivity calculator was enhanced and installed reactivity calculating module by each channel. The ex-core detector was confirmed to be applicable to a large reactor core, such as the CANDU 6 by comparison with the in-core flux detector signal. A preliminary test was performed in Wolsong NPP Unit 2 to verify the robustness of the reactivity calculator. This test convincingly demonstrated that the reactivity calculator

The GAP-TPC

International Nuclear Information System (INIS)

Rossi, B.; Anastasio, A.; Boiano, A.; Cocco, A.G.; Meo, P. Di; Vanzanella, A.; Catalanotti, S.; Covone, G.; Longo, G.; Walker, S.; Fiorillo, G.; Wang, H.; Wang, Y.

2016-01-01

Several experiments have been conducted worldwide, with the goal of observing low-energy nuclear recoils induced by WIMPs scattering off target nuclei in ultra-sensitive, low-background detectors. In the last few decades noble liquid detectors designed to search for dark matter in the form of WIMPs have been extremely successful in improving their sensitivities and setting the best limits. One of the crucial problems to be faced for the development of large size (multi ton-scale) liquid argon experiments is the lack of reliable and low background cryogenic PMTs: their intrinsic radioactivity, cost, and borderline performance at 87 K rule them out as a possible candidate for photosensors. We propose a brand new concept of liquid argon-based detector for direct dark matter search: the Geiger-mode Avalanche Photodiode Time Projection Chamber (GAP-TPC) optimized in terms of residual radioactivity of the photosensors, energy and spatial resolution, light and charge collection efficiency

Radiation detectors laboratory

International Nuclear Information System (INIS)

Ramirez J, F.J.

1996-01-01

The National Institute for Nuclear Research has established a Radiation detector laboratory that has the possibility of providing to the consultants on the handling and applications of the nuclear radiation detectors. It has special equipment to repair the radiation detectors used in spectroscopy as the hyper pure Germanium for gamma radiation and the Lithium-silica for X-rays. There are different facilities in the laboratory that can become useful for other institutions that use radiation detectors. This laboratory was created to satisfy consultant services, training and repairing of the radiation detectors both in national and regional levels for Latin America. The laboratory has the following sections: Nuclear Electronic Instrumentation; where there are all kind of instruments for the measurement and characterization of detectors like multichannel analyzers of pulse height, personal computers, amplifiers and nuclear pulse preamplifiers, nuclear pulses generator, aleatories, computer programs for radiation spectra analysis, etc. High vacuum; there is a vacuum escape measurer, two high vacuum pumps to restore the vacuum of detectors, so the corresponding measurers and the necessary tools. Detectors cleaning; there is an anaerobic chamber for the detectors handling at inert atmosphere, a smoke extraction bell for cleaning with the detector solvents. Cryogenic; there are vessels and tools for handling liquid nitrogen which is used for cooling the detectors when they required it. (Author)

The end of a noble narrative?

DEFF Research Database (Denmark)

Manners, Ian James; Murray, Philomena

2015-01-01

of the forerunner to the current EU we ask if this noble narrative of war and peace, which is at the heart of European integration, at an end. We argue that this principled account is likely to remain just one of several narratives of European integration, but with its reputation somewhat tarnished. Fresh...

Leak detector for a steam generator in FBR type reactors

International Nuclear Information System (INIS)

Miyaji, Nobuyoshi.

1979-01-01

Purpose: To facilitate maintenance for liquid leak detectors such as exchange of nickel membrane sensors during operation in a sodium-cooled fbr type reactor. Constitution: A pipeway capable of supplying a cover gas such as argon into the cylinder of a hydrogen detector containing a nickel membrane sensor is provided in a liquid leak detector constituting a part of a by-pass loop. The pipeway is also adapted to be evacuated. A pipeway and a small sodium tank for drain use are provided on the side of the by-pass loop near valves. Then, after closing the inlet and outlet valves to disconnect the by-pass loop from the sodium main pipeway, the cover gas is supplied to drive liquid sodium to the drain tank. After the drain of the liquid sodium, the sensor can be replaced. (Ikeda, J.)

Detectors for the superconducting super collider, design concepts, and simulation

Energy Technology Data Exchange (ETDEWEB)

Gabriel, T.A.

1989-06-01

The physics of compensation calorimetry is reviewed in the light of the needs of the Superconducting Super Collider (SSC) detectors. The four major detector types: liquid argon, scintillator, room temperature liquids, and silicon, are analyzed with respect to some of their strengths and weaknesses. Finally, general comments are presented which reflect the reliability of simulation code systems.

Detectors for the superconducting super collider, design concepts, and simulation

International Nuclear Information System (INIS)

Gabriel, T.A.

1989-06-01

The physics of compensation calorimetry is reviewed in the light of the needs of the Superconducting Super Collider (SSC) detectors. The four major detector types: liquid argon, scintillator, room temperature liquids, and silicon, are analyzed with respect to some of their strengths and weaknesses. Finally, general comments are presented which reflect the reliability of simulation code systems

The desorption behaviour of implanted noble gases at low energy on silicon surfaces

NARCIS (Netherlands)

Holtslag, A.H.M.; van Silfhout, Arend

1987-01-01

Under UHV conditions, clean crystalline Si(111) surfaces have been bombarded mass-selectively at room temperature with noble gas ions, Ne+, Ar+, Kr+, at normal incidence. By means of stepwise heating up to 1050 K the activation energies and desorbed doses of the noble gases have been straight

X-ray light valve (XLV): a novel detectors' technology for digital mammography

Science.gov (United States)

Marcovici, Sorin; Sukhovatkin, Vlad; Oakham, Peter

2014-03-01

A novel method, based on X-ray Light Valve (XLV) technology, is proposed for making good image quality yet inexpensive flat panel detectors for digital mammography. The digital mammography markets, particularly in the developing countries, demand quality machines at substantially lower prices than the ones available today. Continuous pressure is applied on x-ray detectors' manufacturers to reduce the flat panel detectors' prices. XLV presents a unique opportunity to achieve the needed price - performance characteristics for direct conversion, x-ray detectors. The XLV based detectors combine the proven, superior, spatial resolution of a-Se with the simplicity and low cost of liquid crystals and optical scanning. The x-ray quanta absorbed by a 200 μm a-Se produce electron - hole pairs that move under an electric field to the top and bottom of a-Se layer. This 2D charge distribution creates at the interface with the liquid crystals a continuous (analog) charge image corresponding to the impinging radiation's information. Under the influence of local electrical charges next to them, the liquid crystals twist proportionally to the charges and vary their light reflectivity. A scanning light source illuminates the liquid crystals while an associated, pixilated photo-detector, having a 42 μm pixel size, captures the light reflected by the liquid crystals and converts it in16 bit words that are transmitted to the machine for image processing and display. The paper will describe a novel XLV, 25 cm x 30 cm, flat panel detector structure and its underlying physics as well as its preliminary performance measured on several engineering prototypes. In particular, the paper will present the results of measuring XLV detectors' DQE, MTF, dynamic range, low contrast resolution and dynamic behavior. Finally, the paper will introduce the new, low cost, XLV detector based, digital mammography machine under development at XLV Diagnostics Inc.

Noble gas signatures in the Island of Maui, Hawaii: Characterizing groundwater sources in fractured systems

Science.gov (United States)

Niu, Yi; Castro, M. Clara; Hall, Chris M.; Gingerich, Stephen B.; Scholl, Martha A.; Warrier, Rohit B.

2017-01-01

Uneven distribution of rainfall and freshwater scarcity in populated areas in the Island of Maui, Hawaii, renders water resources management a challenge in this complex and ill-defined hydrological system. A previous study in the Galapagos Islands suggests that noble gas temperatures (NGTs) record seasonality in that fractured, rapid infiltration groundwater system rather than the commonly observed mean annual air temperature (MAAT) in sedimentary systems where infiltration is slower thus, providing information on recharge sources and potential flow paths. Here we report noble gas results from the basal aquifer, springs, and rainwater in Maui to explore the potential for noble gases in characterizing this type of complex fractured hydrologic systems. Most samples display a mass-dependent depletion pattern with respect to surface conditions consistent with previous observations both in the Galapagos Islands and Michigan rainwater. Basal aquifer and rainwater noble gas patterns are similar and suggest direct, fast recharge from precipitation to the basal aquifer. In contrast, multiple springs, representative of perched aquifers, display highly variable noble gas concentrations suggesting recharge from a variety of sources. The distinct noble gas patterns for the basal aquifer and springs suggest that basal and perched aquifers are separate entities. Maui rainwater displays high apparent NGTs, incompatible with surface conditions, pointing either to an origin at high altitudes with the presence of ice or an ice-like source of undetermined origin. Overall, noble gas signatures in Maui reflect the source of recharge rather than the expected altitude/temperature relationship commonly observed in sedimentary systems.

A TPC-like readout method for high precision muon-tracking using GEM-detectors

Energy Technology Data Exchange (ETDEWEB)

Flierl, Bernhard; Biebel, Otmar; Bortfeldt, Jonathan; Hertenberger, Ralf; Klitzner, Felix; Loesel, Philipp; Mueller, Ralph [Ludwig-Maximilians-Universitaet Muenchen (Germany); Zibell, Andre [Julius-Maximilians-Universitaet Wuerzburg (Germany)

2016-07-01

Gaseous electron multiplier (GEM) detectors are well suited for tracking of charged particles. Three dimensional tracking in a single layer can be achieved by application of a time-projection-chamber like readout mode (μTPC), if the drift time of the electrons is measured and the position dependence of the arrival time is used to calculate the inclination angle of the track. To optimize the tracking capabilities for ion tracks drift gas mixtures with low drift velocity have been investigated by measuring tracks of cosmic muons in a compact setup of four GEM-detectors of 100 x 100 x 6 mm{sup 3} active volume each and an angular acceptance of -25 to 25 . The setup consists of three detectors with two-dimensional strip readout layers of 0.4 mm pitch and one detector with a single strip readout layer of 0.25 mm pitch. All strips are readout by APV25 frontend boards and the amplification stage in the detectors consists of three GEM-foils. Tracks are reconstructed by the μTPC-method in one of the detectors and are then compared to the prediction from the other three detectors defined by the center of charge in every detector. We report our study of Argon and Helium based noble gas mixtures with carbon-dioxide as quencher.

Noble gases as cardioprotectants - translatability and mechanism

NARCIS (Netherlands)

Smit, Kirsten F.; Weber, Nina C.; Hollmann, Markus W.; Preckel, Benedikt

2015-01-01

Several noble gases, although classified as inert substances, exert a tissue-protective effect in different experimental models when applied before organ ischaemia as an early or late preconditioning stimulus, after ischaemia as a post-conditioning stimulus or when given in combination before,

A programmable logic controller-based system for the recirculation of liquid C6F14 in the ALICE high momentum particle identification detector at the Large Hadron Collider

International Nuclear Information System (INIS)

Sgura, I.; Cataldo, G. de; Franco, A.; Pastore, C.; Volpe, G.

2012-01-01

The aim of this paper is to present the design and the implementation of the Control System (CS) for the recirculation of liquid Perfluorohexane (C 6 F 14 ) for the ALICE High Momentum Particle Identification detector (HMPID). The HMPID is a detector of the ALICE experiment at the CERN Large Hadron Collider (LHC). It uses liquid C 6 F 14 as Cherenkov radiator medium in twenty-one quartz vessels for the measurement of the charged particles velocity. The primary task of the Liquid Circulation System (LCS) is to ensure the highest transparency of C 6 F 14 to the ultraviolet light. In order to provide safe long term operation a Programmable Logic Controller-based CS has been implemented. CS provides both automatic and manual operating modes, remotely or locally. Its finite state machine design minimizes the possible operator errors and provides a hierarchical control structure allowing the operation and monitoring down to a single radiator vessel. LCS is protected against unsafe working conditions by both active and passive measures. The passive ones are intrinsically guaranteed whereas the active ones are ensured via the control software running in the PLC. The human interface and data archiving are provided via PVSS, the Supervisory Control And Data Acquisition (SCADA) framework which integrates the full detector control. LCS under CS control proved to meet all designed requirements thus enabling HMPID detector to successfully collect data since the very beginning of LHC operation. (authors)

Methods of detecting tritium in gases and liquids

Energy Technology Data Exchange (ETDEWEB)

Petr, I

1977-07-01

Tritium mainly occurs in gases in two chemical forms, i.e., as water vapour (HTO) or elemental hydrogen (HT). Two methods for tritium gas measuring are described. The first consists in the use of an ionization chamber or a proportional counter with the sample sucked in through a filter to the detector working volume. The second consists in the separation of tritium (in the form of HTO) from the gas sample by sorption on silica gel or on molecular sieves and its detection using a liquid or a plastic scintillation detector. Tritium in the form of HT and gaseous organic tritium compounds are determined using the same measuring method after oxidation of the gaseous samples to HTO by burning. A description is given of detectors and measuring methods. Tritium in liquids mainly occurs in the form of tritiated water (HTO). The most commonly used method of tritium detection in liquids is the application of liquid scintillation detectors in which the sample is dissolved or suspended and measured with two photomultipliers in time-coincidence connection. The main advantage of liquid scintillators is the possibility to achieve the 4..pi.. measurement geometry. The methods of calibration and of checking the stability of a measuring system with liquid scintillators are described as are the applications of plastic scintillators in measuring tritium in liquids. Plastic scintillators are less costly in operation and show a more rapid response but their sensitivity is lower. The threshold values of activity are shown in dependence on the detector applied, the chemical form of tritium and the sampling method.

Separation of Asphaltenes by Polarity using Liquid-Liquid Extraction

DEFF Research Database (Denmark)

Andersen, Simon Ivar

1997-01-01

In order to investigate the nature of petroleum asphaltenes in terms of polarity a process was developed using initial liquid-liquid extraction of the oil phase followed by precipitation of the asphaltenes using n-heptane. The liquid-liquid extraction was performed using toluene-methanol mixtures...... phase. The asphaltenes were analysed using FTir, Elemental analysis, and HPLC-SEC with a diode array detector. With increasing content of toluene in the methanol the molecular weight distribution of the asphaltenes significantly move to higher molecular weights. The content of nitrogen and sulfur...

Experience from operating germanium detectors in GERDA

International Nuclear Information System (INIS)

Palioselitis, Dimitrios

2015-01-01

Phase I of the Germanium Detector Array (GERDA) experiment, searching for the neutrinoless double beta (0νββ) decay of 76 Ge, was completed in September 2013. The most competitive half-life lower limit for the 0νββ decay of 76 Ge was set (T- 0ν 1/2 > 2.1 · 10 25 yr at 90% C.L.). GERDA operates bare Ge diodes immersed in liquid argon. During Phase I, mainly refurbished semi-coaxial high purity Ge detectors from previous experiments were used. The experience gained with handling and operating bare Ge diodes in liquid argon, as well as the stability and performance of the detectors during GERDA Phase I are presented. Thirty additional new enriched BEGe-type detectors were produced and will be used in Phase II. A subgroup of these detectors has already been used successfully in GERDA Phase I. The present paper gives an overview of the production chain of the new germanium detectors, the steps taken to minimise the exposure to cosmic radiation during manufacturing, and the first results of characterisation measurements in vacuum cryostats. (paper)

Noble Liquid (Xenon or Krypton) Totally Active Calorimetry

CERN Multimedia

2002-01-01

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

Cucurbit[6]uril: A Possible Host for Noble Gas Atoms.

Science.gov (United States)

Pan, Sudip; Mandal, Subhajit; Chattaraj, Pratim K

2015-08-27

Density functional and ab initio molecular dynamics studies are carried out to investigate the stability of noble gas encapsulated cucurbit[6]uril (CB[6]) systems. Interaction energy, dissociation energy and dissociation enthalpy are calculated to understand the efficacy of CB[6] in encapsulating noble gas atoms. CB[6] could encapsulate up to three Ne atoms having dissociation energy (zero-point energy corrected) in the range of 3.4-4.1 kcal/mol, whereas due to larger size, only one Ar or Kr atom encapsulated analogues would be viable. The dissociation energy value for the second Ar atom is only 1.0 kcal/mol. On the other hand, the same for the second Kr is -0.5 kcal/mol, implying the instability of the system. The noble gas dissociation processes are endothermic in nature, which increases gradually along Ne to Kr. Kr encapsulated analogue is found to be viable at room temperature. However, low temperature is needed for Ne and Ar encapsulated analogues. The temperature-pressure phase diagram highlights the region in which association and dissociation processes of Kr@CB[6] would be favorable. At ambient temperature and pressure, CB[6] may be used as an effective noble gas carrier. Wiberg bond indices, noncovalent interaction indices, electron density, and energy decomposition analyses are used to explore the nature of interaction between noble gas atoms and CB[6]. Dispersion interaction is found to be the most important term in the attraction energy. Ne and Ar atoms in one Ng entrapped analogue are found to stay inside the cavity of CB[6] throughout the simulation at 298 K. However, during simulation Ng2 units in Ng2@CB[6] flip toward the open faces of CB[6]. After 1 ps, one Ne atom of Ne3@CB[6] almost reaches the open face keeping other two Ne atoms inside. At lower temperature (77 K), all the Ng atoms in Ngn@CB[6] remain well inside the cavity of CB[6] throughout the simulation time (1 ps).

Noble gas encapsulation into carbon nanotubes: Predictions from analytical model and DFT studies

Energy Technology Data Exchange (ETDEWEB)

Balasubramani, Sree Ganesh; Singh, Devendra; Swathi, R. S., E-mail: swathi@iisertvm.ac.in [School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Kerala 695016 (India)

2014-11-14

The energetics for the interaction of the noble gas atoms with the carbon nanotubes (CNTs) are investigated using an analytical model and density functional theory calculations. Encapsulation of the noble gas atoms, He, Ne, Ar, Kr, and Xe into CNTs of various chiralities is studied in detail using an analytical model, developed earlier by Hill and co-workers. The constrained motion of the noble gas atoms along the axes of the CNTs as well as the off-axis motion are discussed. Analyses of the forces, interaction energies, acceptance and suction energies for the encapsulation enable us to predict the optimal CNTs that can encapsulate each of the noble gas atoms. We find that CNTs of radii 2.98 − 4.20 Å (chiral indices, (5,4), (6,4), (9,1), (6,6), and (9,3)) can efficiently encapsulate the He, Ne, Ar, Kr, and Xe atoms, respectively. Endohedral adsorption of all the noble gas atoms is preferred over exohedral adsorption on various CNTs. The results obtained using the analytical model are subsequently compared with the calculations performed with the dispersion-including density functional theory at the M06 − 2X level using a triple-zeta basis set and good qualitative agreement is found. The analytical model is however found to be computationally cheap as the equations can be numerically programmed and the results obtained in comparatively very less time.

Results of low energy background measurements with the Liquid Scintillation Detector (LSD) of the Mont Blanc Laboratory

Science.gov (United States)

Aglietta, M.; Badino, G.; Bologna, G. F.; Castagnoli, C.; Fulgione, W.; Galeotti, P.; Saavedra, O.; Trinchero, G. C.; Vernetto, S.; Dadykin, V. L.

1985-01-01

The 90 tons liquid scintillation detector (LSD) is fully running since October 1984, at a depth of 5,200 hg/sq cm of standard rock underground. The main goal is to search for neutrino bursts from collapsing stars. The experiment is very sensitive to detect low energy particles and has a very good signature to gamma-rays from (n,p) reaction which follows the upsilon e + p yields n + e sup + neutrino capture. The analysis of data is presented and the preliminary results on low energy measurements are discussed.

Results of low energy background measurements with the liquid scintillation detector (LSD) of the Mont Blanc Laboratory

International Nuclear Information System (INIS)

Aglietta, M.; Badino, G.; Bologna, G.F.

1985-01-01

The 90 tons liquid scintillation detector (LSD) has been fully running since October 1984 at a depth of 5,200 hg/sq cm of standard rock underground. The main goal is to search for neutrino bursts from collapsing stars. The experiment is very sensitive to detect low energy particles and has a very good signature to gamma rays from (n,p) reactions which follows the upsilon e + p yields n + e sup + neutrino capture. The analysis of data is presented and the preliminary results on low energy measurements are discussed. 1 ref

Noble Metal/Ceramic Composites in Flame Processes

DEFF Research Database (Denmark)

Schultz, Heiko; Madler, Lutz; Strobel, Reto

conditions influence the resulting noble metal particles size in those systems [1]. For every specific application the particle size and the metal/metal oxide interaction affect the performance of these nano-composite materials [2]. Recently, aerosol processes have been successfully used to produce platinum...

Detectors for the Superconducting Super Collider, design concepts, and simulation

International Nuclear Information System (INIS)

Gabriel, T.A.

1989-01-01

The physics of compensation calorimetry is reviewed in the light of the need of the Superconducting Super Collider (SSC) detectors. The four major detector types: liquid argon, scintillator, room temperature liquids, and silicon, are analyzed with respect to some of their strengths and weaknesses. Finally, general comments are presented which reflect the reliability of simulation code systems. 29 refs., 20 figs., 6 tabs

NOBLE METAL CHEMISTRY AND HYDROGEN GENERATION DURING SIMULATED DWPF MELTER FEED PREPARATION

Energy Technology Data Exchange (ETDEWEB)

Koopman, D

2008-06-25

Simulations of the Defense Waste Processing Facility (DWPF) Chemical Processing Cell vessels were performed with the primary purpose of producing melter feeds for the beaded frit program plus obtaining samples of simulated slurries containing high concentrations of noble metals for off-site analytical studies for the hydrogen program. Eight pairs of 22-L simulations were performed of the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles. These sixteen simulations did not contain mercury. Six pairs were trimmed with a single noble metal (Ag, Pd, Rh, or Ru). One pair had all four noble metals, and one pair had no noble metals. One supporting 4-L simulation was completed with Ru and Hg. Several other 4-L supporting tests with mercury have not yet been performed. This report covers the calculations performed on SRNL analytical and process data related to the noble metals and hydrogen generation. It was originally envisioned as a supporting document for the off-site analytical studies. Significant new findings were made, and many previous hypotheses and findings were given additional support as summarized below. The timing of hydrogen generation events was reproduced very well within each of the eight pairs of runs, e.g. the onset of hydrogen, peak in hydrogen, etc. occurred at nearly identical times. Peak generation rates and total SRAT masses of CO{sub 2} and oxides of nitrogen were reproduced well. Comparable measures for hydrogen were reproduced with more variability, but still reasonably well. The extent of the reproducibility of the results validates the conclusions that were drawn from the data.

Developmental and Metabolic Plasticity of White-Skinned Grape Berries in Response to Botrytis cinerea during Noble Rot1[OPEN

Science.gov (United States)

Collins, Thomas S.; Vicente, Ariel R.; Doyle, Carolyn L.; Ye, Zirou; Allen, Greg; Heymann, Hildegarde

2015-01-01

Noble rot results from exceptional infections of ripe grape (Vitis vinifera) berries by Botrytis cinerea. Unlike bunch rot, noble rot promotes favorable changes in grape berries and the accumulation of secondary metabolites that enhance wine grape composition. Noble rot-infected berries of cv Sémillon, a white-skinned variety, were collected over 3 years from a commercial vineyard at the same time that fruit were harvested for botrytized wine production. Using an integrated transcriptomics and metabolomics approach, we demonstrate that noble rot alters the metabolism of cv Sémillon berries by inducing biotic and abiotic stress responses as well as ripening processes. During noble rot, B. cinerea induced the expression of key regulators of ripening-associated pathways, some of which are distinctive to the normal ripening of red-skinned cultivars. Enhancement of phenylpropanoid metabolism, characterized by a restricted flux in white-skinned berries, was a common outcome of noble rot and red-skinned berry ripening. Transcript and metabolite analyses together with enzymatic assays determined that the biosynthesis of anthocyanins is a consistent hallmark of noble rot in cv Sémillon berries. The biosynthesis of terpenes and fatty acid aroma precursors also increased during noble rot. We finally characterized the impact of noble rot in botrytized wines. Altogether, the results of this work demonstrated that noble rot causes a major reprogramming of berry development and metabolism. This desirable interaction between a fruit and a fungus stimulates pathways otherwise inactive in white-skinned berries, leading to a greater accumulation of compounds involved in the unique flavor and aroma of botrytized wines. PMID:26450706

New C$_{6}$D$_{6}$ detectors: reduced neutron sensitivity and improved safety

CERN Document Server

Mastinu, Pierfrancesco; Berthoumieux, Eric; Cano-Ott, Daniel; Gramegna, F; Guerrero, Carlos; Massimi, Cristian; Milazzo, Paolo Maria; Mingrone, Federica; Praena, Javier; Prete, G; García, Aczel Regino

2013-01-01

During the 2011 data measurement campaign at n_TOF, the liquid scintillator detectors developed at FZK-Karlsruhe (hereafter named K6D6, [1]) and used with success along 10 years have shown ageing problems, mainly related to liquid leakage. The mould used to produce the carbon fiber structure, containing the liquid and the detection elements, was not available anymore and the technician involved in its construction was retired. Once decided to proceed to the production of new detectors (L6D6 in the following) two major items have been identified: - The detector setup must be able to work in the new class A experimental area (safety requirements advise to avoid the use of the old K6D6 in this area). - If possible, it is useful to reduce the neutron sensitivity, with the aim to have a liquid scintillator detector with very low neutron sensitivity (improving the already high performing K6D6). [1] R.Plag et al., NIM A496 (2003) 425

SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

International Nuclear Information System (INIS)

Muthukumaran, M; Manigandan, D; Murali, V; Chitra, S; Ganapathy, K; Vikraman, S

2016-01-01

Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volume of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.

SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

Energy Technology Data Exchange (ETDEWEB)

Muthukumaran, M [Apollo Speciality Hospitals, Chennai, Tamil Nadu (India); Manigandan, D [Fortis Cancer Institute, Mohali, Punjab (India); Murali, V; Chitra, S; Ganapathy, K [Apollo Speciality Hospital, Chennai, Tamil Nadu (India); Vikraman, S [Jaypee Hospital – Radiation Onology, Noida, UTTAR PRADESH (India)

2016-06-15

Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volume of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.

Christian Values and Noble Ideas of Rank and their Consequences on Symbolic Acts

Directory of Open Access Journals (Sweden)

Gerd ALTHOFF

2007-12-01

Full Text Available In the Middle Ages a Christian system of values met the values of a noble warrior society. Although these two systems had completely different conceptions of norms, they adapted from each other certain values and symbolic forms to express these values.The development of this adaptation is depicted by treating the Christian values misericordia, humilitas and clementia. In which way did the noble warrior society take up these values and how did these norms possibly change?Misericordia, for example, became an essential part of noble behaviour, but the fundamental idea of Christian misericordia was changed. Helping the poor was often motivated by the nobles’ will to prove his mercy, not by personal compassion.Although the value of humilitas implied a sharp contrast to the values of honor and rank, one can find forms of expression, which revealed a noble’s or ruler’s humility. With his humble behaviour one proved one’s qualification and legitimacy. Humility was expressed with symbolic forms of expression like walking barefoot and in penitential clothes or making footfalls. Similarly, these forms were used in inner-secular communication to acknowledge the existing order of rank.The ritual of deditio combines the values humilitas and clementia. The author describes this ritual as a pre-arranged stage-play, in which the one’s humility granted the other’s clemency. These ‘stage-plays’ had only little in common with the original Christian virtues, but this way several elements of the Christian virtue system influenced the noble behaviour pattern.En la edad media el sistema de valores cristiano confluye con el de una sociedad noble guerrera. Aunque ambos sistemas tuvieron dos concepciones de normas completamente diferentes, sin embargo, cada uno de ellos adapto ciertos valores y sus expresiones simbólicas del otro.El desarrollo de esta adaptación es descrito a través de los valores cristianos de misericordia, humilitas y clementia �

Organ protection by the noble gas helium

NARCIS (Netherlands)

Smit, K.F.

2017-01-01

The aims of this thesis were to investigate whether helium induces preconditioning in humans, and to elucidate the mechanisms behind this possible protection. First, we collected data regarding organ protective effects of noble gases in general, and of helium in particular (chapters 1-3). In chapter

Commissioning the SNO+ Detector

Science.gov (United States)

Caden, E.; Coulter, I.; SNO+ Collaboration

2017-09-01

SNO+ is a multipurpose liquid scintillator neutrino experiment based at SNOLAB in Sudbury, Ontario, Canada. The experiment’s main physics goal is a search for neutrinoless double beta decay in Tellurium-130, but SNO+ will also study low energy solar neutrinos, geo- and reactor-antineutrinos, among other topics. We are reusing much of the hardware from the original SNO experiment, but significant work has taken place to transform the heavy water detector into a liquid scintillator detector. We present upgrades and improvements to the read-out electronics and trigger system to handle the higher data rates expected by a scintillator experiment. We show the successful installation and testing of a hold-down rope net for the acrylic vessel to counter-act the buoyancy of organic liquid scintillator. We also describe the new scintillator process plant and cover gas systems that have been constructed to achieve the purification necessary to meet our physics goals. We are currently commissioning the experiment with ultra-pure water in preparation for filling with scintillator in early 2017 and present the current status of this work.

The efficacy of noble metal alloy urinary catheters in reducing catheter-associated urinary tract infection

Directory of Open Access Journals (Sweden)

Alanood Ahmed Aljohi

2016-01-01

Results: A 90% relative risk reduction in the rate of CAUTI was observed with the noble metal alloy catheter compared to the standard catheter (10 vs. 1 cases, P = 0.006. When considering both catheter-associated asymptomatic bacteriuria and CAUTI, the relative risk reduction was 83% (12 vs. 2 cases, P = 0.005. In addition to CAUTI, the risk of acquiring secondary bacteremia was lower (100% for the patients using noble metal alloy catheters (3 cases in the standard group vs. 0 case in the noble metal alloy catheter group, P = 0.24. No adverse events related to any of the used catheters were recorded. Conclusion: Results from this study revealed that noble metal alloy catheters are safe to use and significantly reduce CAUTI rate in ICU patients after 3 days of use.

Electronic spectral detection in liquid chromatography

Energy Technology Data Exchange (ETDEWEB)

Biggs, Wilton R. [ChevronTexaco Chemical Co., P. O. Box 1627, Richmond, CA 94802 (United States); Fetzer, John C. [Fetzpahs Consulting, 1283 Santa Fe St., Hercules, CA 94547 (United States)

2002-07-01

The use of absorbance and fluorescence spectrometers as liquid chromatography detectors is described. These detectors offer sensitive detection that can also identify the peaks in a chromatogram. Many examples, mainly from the separation of polycyclic aromatic hydrocarbons, are given that show the selectivity and usefulness of these detectors. (orig.)

Natural Death and the Noble Savage.

Science.gov (United States)

Walter, Tony

1995-01-01

The belief that dying and grieving are natural processes is widely held in modern bereavement care. Examines four assumption often made in this connection: (1) most primitive cultures deal with death in an accepting way; (2) this way is different than our own; (3) it is a good and noble way; and (4) traditional societies see death as natural. (JBJ)

Ethanol concentration in 56 refillable electronic cigarettes liquid formulations determined by headspace gas chromatography with flame ionization detector (HS-GC-FID).

Science.gov (United States)

Poklis, Justin L; Wolf, Carl E; Peace, Michelle R

2017-10-01

Personal battery-powered vaporizers or electronic cigarettes were developed as an alternative to traditional cigarettes. The modern electronic cigarettes were patented in 2004 by Hon Lik in China. In May 2016, the US Food and Drug Administration (FDA) imposed regulatory statutes on e-cigarettes and their liquid formulations (e-liquids); prior to that, they were unregulated. E-liquids are typically composed of propylene glycol and/or glycerin, flavouring component(s), and active ingredient(s), such as nicotine. Fifty-six commercially available e-liquids, purchased from various sources, contained a variety of flavours and active ingredients. A headspace gas chromatography with flame ionization detector (HS-GC-FID) method was used to analyze these e-liquids for volatiles content. Only one of the e-liquids listed ethanol as a component. The chromatographic separation of volatiles was performed on a Restek BAC-1 column. A linear calibration was generated for ethanol with limits of detection and quantification (LOD/LOQ) of 0.05 mg/mL. Ethanol concentrations in the 56 e-liquids ranged from none detected to 206 mg/mL. The ethanol determined in these products may have been used in flavourants or a solvent; the reason for inclusion cannot be fully ascertained. The implications of vaporizing ethanol as an e-liquid component are unknown. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of halogens on interactions between a reduced TiO{sub 2} (110) surface and noble metal atoms: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Tada, Kohei, E-mail: k-tada@aist.go.jp [Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043 (Japan); Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka, 563-8577 (Japan); Koga, Hiroaki [Element Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo Ohara, Nishikyo, Kyoto, 615-8245 (Japan); Hayashi, Akihide; Kondo, Yudai; Kawakami, Takashi; Yamanaka, Shusuke [Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043 (Japan); Okumura, Mitsutaka [Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka, 560-0043 (Japan); Element Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo Ohara, Nishikyo, Kyoto, 615-8245 (Japan)

2017-07-31

Highlights: • We investigated the halogen effect on the interactions of noble metals with TiO{sub 2}. • Halogen atoms inhibit electron transfer from TiO{sub 2} to noble metals. • Iodine stabilizes the adsorption of noble metals especially for Ag and Cu. • Electron transfer from the TiO{sub 2} is effective in anchoring Au and Pt atoms. • Covalent interaction with the support is effective in anchoring Ag and Cu atoms. - Abstract: Using DFT calculation, we investigate the effects of halogens on the interactions between rutile TiO{sub 2} (110) and noble metal atoms (Au, Ag, Cu, Pt, and Pd). Fluorine, chlorine, and bromine atoms occupy the oxygen defect sites of TiO{sub 2}, decreasing the stability of noble metal atoms on the surface. This decrease occurs because the halogens inhibit electron transfer from TiO{sub 2} to the noble metal atoms; the electron transfer from reduced TiO{sub 2} to the noble metal atom stabilizes the noble metal atom adsorption. In contrast, iodine strengthens the interactions between TiO{sub 2} and some noble metal atoms, namely Ag and Cu. This stabilization occurs because of the covalent interaction between iodine-doped TiO{sub 2} and the noble metal atom. Therefore, the stabilization is explained well by chemical hardness. This result suggests that iodine-doping of a TiO{sub 2} surface would be an effective method for the preparation of highly stabilized noble metal clusters.

Mantle Noble Gas Contents Controlled by Subduction of Serpentinite

Science.gov (United States)

Krantz, J. A.; Parman, S. W.; Kelley, S. P.; Smye, A.; Jackson, C.

2017-12-01

Geochemical analyses of exhumed subduction zone material1, well gases2, MORB, and OIBs3 indicate that noble gases are being recycled from the surface of the earth into the mantle. However, the path taken by these noble gases is unclear. To estimate the distribution and quantity of Ar, Kr, and Xe in subducting slabs, a model consisting of layers of sediments, altered oceanic crust (AOC), and serpentinite (hydrously altered mantle) has been developed. The noble gas contents of sediments and AOC were calculated using the least air-like and most gas-rich analyses from natural systems4,5, while serpentinite was modelled using both data from natural systems1 and experimentally determined solubilities. Layer thicknesses were assessed over a range of values: 1 to 12 km of sediments, 5 to 9 km of AOC, and 1 to 30 km of serpentinite. In all cases, the serpentinite layer contains at least an order of magnitude more Ar and Kr than the other layers. For realistic layer thicknesses (1 km of sediments, 6 km of AOC, and 3 km of serpentinite), Xe is distributed roughly equally between the three layers. By incorporating global subduction rates6, fluxes of the heavy noble gases into the mantle have been calculated as 4 · 1012 mol/Ma for 36Ar, 6 · 1011 mol/Ma for 84Kr, and 8 · 109 mol/Ma for 130Xe. These fluxes are equivalent to the total 84Kr and 130Xe contents of the depleted and bulk mantle over 1 and 10 Ma7. Similarly, the flux of 36Ar is equivalent over 1 and 100 Ma. Since the Kr and Xe have not been completely overprinted by recycling, the large majority of subducted noble gases must escape in the subduction zone. However, even the small amounts that are subducted deeper have affected the mantle as measured in both MORB and OIBs. 1. Kendrick, M.A. et al., Nature Geoscience, 4, 807-812, 2011 2. Holland, G. and Ballentine, C.J., Nature, 441, 186-191, 2006 3. Parai, R. and Mukhopadhyay, S., G3, 16, 719-735, 2015 4. Matsuda, J. and Nagao, K., Geochemical Journal, 20, 71-80, 1986

Solid polymer electrolyte composite membrane comprising a porous support and a solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide

Science.gov (United States)

Liu, Han; Mittelsteadt, Cortney K; Norman, Timothy J; Griffith, Arthur E; LaConti, Anthony B

2015-02-24

A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a thin, rigid, dimensionally-stable, non-electrically-conducting support, the support having a plurality of cylindrical, straight-through pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores are unevenly distributed, with some or no pores located along the periphery and more pores located centrally. The pores are completely filled with a solid polymer electrolyte, the solid polymer electrolyte including a dispersed reduced noble metal or noble metal oxide. The solid polymer electrolyte may also be deposited over the top and/or bottom surfaces of the support.

Synthesis of Zeolite Materials for Noble Gas Separation

International Nuclear Information System (INIS)

Achey, R.; Rivera, O.; Wellons, M.; Hunter, D.

2017-01-01

Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.

Synthesis of Zeolite Materials for Noble Gas Separation

Energy Technology Data Exchange (ETDEWEB)

Achey, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rivera, O. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wellons, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hunter, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-10-02

Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.

Preparation and Heat-Treatment of DWPF Simulants With and Without Co-Precipitated Noble Metals

International Nuclear Information System (INIS)

Koopman, David C.:Eibling, Russel E

2005-01-01

The Savannah River National Laboratory is in the process of investigating factors suspected of impacting catalytic hydrogen generation in the Chemical Process Cell of the Defense Waste Processing Facility, DWPF. Noble metal catalyzed hydrogen generation in simulation work constrains the allowable acid addition operating window in DWPF. This constraint potentially impacts washing strategies during sludge batch preparation. It can also influence decisions related to the addition of secondary waste streams to a sludge batch. Noble metals have historically been added as trim chemicals to process simulations. The present study investigated the potential conservatism that might be present from adding the catalytic species as trim chemicals to the final sludge simulant versus co-precipitating the noble metals into the insoluble sludge solids matrix. Parallel preparations of two sludge simulants targeting the composition of Sludge Batch 3 were performed in order to evaluate the impact of the form of noble metals. Identical steps were used except that one simulant had dissolved palladium, rhodium, and ruthenium present during the precipitation of the insoluble solids. Noble metals were trimmed into the other stimulant prior to process tests. Portions of both sludge simulants were held at 97 C for about eight hours to qualitatively simulate the effects of long term storage on particle morphology and speciation. The simulants were used as feeds for Sludge Receipt and Adjustment Tank, SRAT, process simulations. The following conclusions were drawn from the simulant preparation work: (1) The first preparation of a waste slurry simulant with co-precipitated noble metals was successful, based on the data obtained. It appears that 99+% of the noble metals were retained in the simulant. (2) Better control of carbonate, hydroxide, and post-wash trim chemical additions is needed before the new method of simulant preparation will be as reproducible as the old method. (3) The two new

Noble metal behavior during melting of simulated high-level nuclear waste glass feeds

International Nuclear Information System (INIS)

Anderson, L.D.; Dennis, T.; Elliott, M.L.; Hrma, P.

1994-01-01

Noble metals and their oxides can settle in waste glass melters and cause electrical shorting. Simulate waste feeds from Hanford, Savannah River, and Kernforschungszentrum Karlsruhe were heat treated for 1 hour in a gradient furnace at temperatures ranging from approximately 600 degrees C to 1000 degrees C and examined by electron microscopy to determine shapes, sizes, and distribution of noble metal particles as a function of temperature. Individual noble metal particles and agglomerates of rhodium (Rh), ruthenium (RuO 2 ), and palladium (Pd), as well as their alloys, were seen. The majority of particles and agglomerates were generally less than 10 μm; however, large agglomerations (up to 1 mm) were found in the German feed. 5 refs., 6 figs., 2 tabs

Report of the general purpose detector group

International Nuclear Information System (INIS)

Barbaro-Galtieri, A.; Bartel, W.; Bulos, F.; Cool, R.; Hanson, G.; Koetz, U.; Kottahaus, R.; Loken, S.; Luke, D.; Rothenberg, A.

1975-01-01

A general purpose detector for PEP is described. The main components of this detector are a l meter radius, 15 kilogauss superconducting solenoidal magnet with drift chambers to detect and measure the momentum of charged particles, a liquid argon neutral detector and hadron calorimeter, and a system of Cherenkov and time-of-flight counters for identification of charged hadrons. A major consideration in the design of this detector was that it be flexible: the magnet coil and drift chambers form a core around which various apparatus for specialized detection can be placed

A Scintillator Purification System for the Borexino Solar Neutrino Detector

OpenAIRE

Benziger, J.; Cadonati, L.; Calaprice, F.; Chen, M.; Corsi, A.; Dalnoki-Veress, F.; Fernholz, R.; Ford, R.; Galbiati, C.; Goretti, A.; Harding, E.; Ianni, Aldo; Ianni, Andrea; Kidner, S.; Leung, M.

2007-01-01

Purification of the 278 tons of liquid scintillator and 889 tons of buffer shielding for the Borexino solar neutrino detector was performed with a system that combined distillation, water extraction, gas stripping and filtration. The purification of the scintillator achieved unprecedented low backgrounds for the large scale liquid scintillation detector. This paper describes the principles of operation, design, construction and commissioning of the purification system, and reviews the require...

Polymer-noble metal nanocomposites: Review

CSIR Research Space (South Africa)

Folarin, OM

2011-09-01

Full Text Available because of their multi-functionality, ease of process-ability, potential for large-scale manufacturing, significantly lighter than metals, ease of synthesis when compared to the oxide/noble metal multi-layers (Gass et al., 2006; Lee et al., 2003.... their easy aggregation arising from their high surface free energy (Lee et al., 2006). In the design of nanocomposites, one must consider the properties of the polymer matrix as well as the stability of the nanoparticles and more importantly...

Techniques for the quantitative analysis of fission-product noble metals

International Nuclear Information System (INIS)

Lautensleger, A.W.; Hara, F.T.

1982-08-01

Analytical procedures for the determination of ruthenium, rhodium, and palladium in precursor waste, solvent metal, and final glass waste forms have been developed. Two procedures for the analysis of noble metals in the calcine and glass waste forms are described in this report. The first is a fast and simple technique that combines inductively coupled argon plasma atomic emission spectrometry (ICP) and x-ray fluorescence techniques and can only be used on nonradioactive materials. The second procedure is based on a noble metal separation step, followed by an analysis using ICP. This second method is more complicated than the first, but it will work on radioactive materials. Also described is a procedure for the ICP analysis of noble metals in the solvent metal matrix. The only solvent metal addressed in this procedure is lead, but with minor changes the procedure could be applied to any of the solvent metals being considered in the Pacific Northwest Laboratory (PNL) extraction process. A brief explanation of atomic spectroscopy and the ICP analytical process, as well as of certain aspects of ICP performance (interelement spectral line interferences and certain matrix effects) is given

Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing.

Science.gov (United States)

Chen, Chen; Tang, Yongan; Vlahovic, Branislav; Yan, Fei

2017-12-01

The integration of different noble metal nanostructures, which exhibit desirable plasmonic and/or electrocatalytic properties, with electrospun polymer nanofibers, which display unique mechanical and thermodynamic properties, yields novel hybrid nanoscale systems of synergistic properties and functions. This review summarizes recent advances on how to incorporate noble metal nanoparticles into electrospun polymer nanofibers and illustrates how such integration paves the way towards chemical sensing applications with improved sensitivity, stability, flexibility, compatibility, and selectivity. It is expected that further development of this field will eventually make a wide impact on many areas of research.

Noble gas control room accident filtration system for severe accident conditions N-CRAFT. System design

International Nuclear Information System (INIS)

Hill, Axel

2014-01-01

Severe accidents might cause the release of airborne radioactive substances to the environment of the NPP. This can either be due to leakages of the containment or due to a filtered containment venting in order to ensure the overall integrity of the containment. During the containment venting process aerosols and iodine can be retained by the FCVS which prevents long term ground contamination. Noble gases are not retainable by the FCVS. From this it follows that a large amount of radioactive noble gases (e.g. xenon, krypton) might be present in the nearby environment of the plant dominating the activity release, depending on the venting procedure and the weather conditions. Accident management measures are necessary in case of severe accidents and the prolonged stay of staff inside the main control room (MCR) or emergency response center (ERC) is essential. Therefore, the in leakage and contamination of the MRC and ERC with airborne activity has to be prevented. The radiation exposure of the crises team needs to be minimized. The entrance of noble gases cannot be sufficiently prevented by the conventional air filtration systems such as HEPA filters and iodine absorbers. With the objective to prevent an unacceptable contamination of the MCR/ERC atmosphere by noble gases AREVA GmbH has developed a noble gas retention system. The noble gas control room accident filtration system CRAFT is designed for this case and provides supply of fresh air to the MCR/ERC without time limitation. The retention process of the system is based on the dynamic adsorption of noble gases on activated carbon. The system consists of delay lines (carbon columns) which are operated by a continuous and simultaneous adsorption and desorption process. These cycles ensure a periodic load and flushing of the delay lines retaining the noble gases from entering the MCR. CRAFT allows a minimization of the dose rate inside MCR/ERC and ensures a low radiation exposure to the staff on shift maintaining

Background reduction at low energies with BEGe detector operated in liquid argon using the GERDA-LArGe facility

Energy Technology Data Exchange (ETDEWEB)

Budjas, Dusan [Physik-Department E15, Technische Universitaet Muenchen (Germany); Collaboration: GERDA-Collaboration

2014-07-01

LArGe is a low background test facility used for proving innovative approaches to background reduction in support of the neutrinoless double beta decay experiment Gerda. These approaches include an anti-Compton veto using scintillation light detection from liquid argon, as well as a novel pulse shape discrimination method exploiting the characteristic electrical field distribution inside BEGe detectors. The latter technique can identify single-site events (typical for double beta decays) and efficiently reject multi-site events (typical for backgrounds from gamma-ray interactions), as well as different types of background events from detector surfaces. While the main focus of the LArGe facility is to assist with reaching the goal of Gerda - improving the sensitivity for {sup 76}Ge neutrinoless double beta decay search, reducing the background at low energies and lowering the energy threshold is also of interest. In particular such efforts can be potentially relevant for search of dark matter or low energy neutrino interactions. In this talk I present the experimental measurement of the low energy region with a BEGe detector operated in LArGe with the application of powerful background suppression methods. The performance will be compared to that of some dedicated dark matter detection experiments.

Application of liquid metals for the extraction of solid metals

International Nuclear Information System (INIS)

Borgstedt, H.U.

1996-01-01

Liquid metals dissolve several solid metals in considerable amounts at moderate temperatures. The dissolution processes may be based upon simple physical solubility, formation of intermetallic phases. Even chemical reactions are often observed in which non-metallic elements might be involved. Thus, the capacity to dissolve metals and chemical properties of the liquid metals play a role in these processes. Besides the solubility also chemical properties and thermochemical data are of importance. The dissolution of metals in liquid metals can be applied to separate the solutes from other metals or non-metallic phases. Relatively noble metals can be chemically reduced by the liquid phases. Such solution processes can be applied in the extractive metallurgy, for instance to extract metals from metallic waste. The recycling of metals is of high economical and ecological importance. Examples of possible processes are discussed. (author)

First 10 kg of naked germanium detectors installed in liquid nitrogen in GENIUS Test-Facility in GRAN-SASSO

Energy Technology Data Exchange (ETDEWEB)

Klapdor-Kleingrothaus, H.V. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

2004-07-01

The GENIUS Test Facility has come into operation in Gran Sasso on May 5, 2003 with its first ten kg of naked Ge detectors in liquid nitrogen. This is the first time that this novel technique for extreme background reduction in search for rare decays is applied under the background conditions of an underground laboratory. GENIUS-TF has the potential to check the DAMA evidence for cold dark matter by modulation, and possibly, to improve the accuracy of the recently observed first signal for neutrinoless double beta decay. (orig.)

First 10 kg of naked germanium detectors installed in liquid nitrogen in GENIUS Test-Facility in GRAN-SASSO

International Nuclear Information System (INIS)

Klapdor-Kleingrothaus, H.V.

2004-01-01

The GENIUS Test Facility has come into operation in Gran Sasso on May 5, 2003 with its first ten kg of naked Ge detectors in liquid nitrogen. This is the first time that this novel technique for extreme background reduction in search for rare decays is applied under the background conditions of an underground laboratory. GENIUS-TF has the potential to check the DAMA evidence for cold dark matter by modulation, and possibly, to improve the accuracy of the recently observed first signal for neutrinoless double beta decay. (orig.)

Characterization of a glass GEM for sealed detectors application and reduction of charging-up effects

CERN Document Server

Erdal, Eran

2014-01-01

Apart from high energy physics experiments, there has been a great effort in recent years to incorporate MPGDs in many other applications i.e. medical treatments and imaging and home land security. However, MPGDs (as most gaseous detectors) are normally operated under a constant flushing of the gas. Their use thus turns them expensive since they rely on a constant gas supply and a suitable infrastructure, but most important is the loss of their portability. These reasons have pushed the community to search for other solutions, aiming for the development of sealed detectors. The demands for such is to be made out of low outgassing rate materials and possibly the use of only noble gas to avoid aging due to chemical activity of the ionized gas of the avalanche. The default material for GEM detectors - Polyimide (Kapton), is not suitable for a sealed detector because of its high outgassing rate, thus calling for new solutions. Moreover, GEMs, being essentially made out of an insulating material, pose a problem in...

Computer-aided design and construction of an antineutrino detector

International Nuclear Information System (INIS)

Stutz, A.

1989-01-01

The Bugey group is setting-up a new detector for another neutrino oscillation experiment. This thesis reports on the different steps concerning its realisation. Light yield, light transmission and pulse shape discrimination properties of NE 320 a new liquid scintillator loaded with 0.15% of Lithium 6 allow to realise a large volume detector (3 x 600 l) with an order of magnitude increase in sensitivity. The benefit of the neutron capture on Lithium 6 has been conserved owing to the segmentation of the whole detector volume in 98 cells and to energy resolution and pulse shape discrimination properties of the liquid. The efficiency is expected to be 0.5 and the essential component of the background is the natural activity of the scintillator. This makes this detector the most performant for neutrino oscillation experiment at reactor [fr

Measurements of the proton light output function of the organic liquid scintillator NE213 in several detectors

Energy Technology Data Exchange (ETDEWEB)

Hawkes, N.P.; Adams, J.M.; Bond, D.S.; Croft, S; Jarvis, O.N. E-mail: onj@jet.uk; Watkins, N

2002-01-01

When using an organic liquid scintillator such as NE213 for neutron spectrometry, the light output as a function of proton energy is needed in order to unfold the neutron spectrum from the scintillator's pulse height distribution. We have measured this function for several detectors over the range 1.5-16 MeV approximately, using monoenergetic neutrons from the Harwell 5 MV Van de Graaff accelerator. Results were obtained for a wide variety of sizes and shapes of the scintillator cell, and were found to be essentially in agreement within errors. The results were also compared with those of several other workers (amongst whom there is considerable disagreement). Below 10 MeV, there is excellent agreement with one worker and moderate or poor agreement with others; above 10 MeV, agreement is moderate in all cases. We conclude that workers wishing to unfold neutron spectra from NE213 pulse height distributions would be advised to make measurements with their own particular detector configuration, rather than use published functions.

Intentions of fast noble gas ions with clean and with oxidized monocrystalline copper surfaces

International Nuclear Information System (INIS)

Wit, A.G.J. de.

1979-01-01

The thesis reports investigations concerning the distorted shape of the energy distribution of scattered noble gas ions, and investigations of angular distributions of these ions where a quantitative interpretation is less hampered by preferential neutralization. Low energy noble gas ion scattering is used to study the interactions between oxygen gas and Cu(110) surfaces. (Auth.)

Comparison of various stopping gases for 3He-based position sensitive neutron detectors

International Nuclear Information System (INIS)

Doumas, A.; Smith, G.C.

2012-01-01

A range of solid state, scintillator and gas based detectors are being developed for use at the next generation of high flux neutron facilities. Since gas detectors are expected to continue to play a key role in future specific thermal neutron experiments, a comparison of the performance characteristics of prospective stopping gases is beneficial. Gas detectors typically utilize the reaction 3 He(n,p)t to detect thermal neutrons; the 3 He gas is used in a mixture containing a particular stopping gas in order to maintain relatively short ranges for the proton and triton pair emitted from the n- 3 He reaction. Common stopping gases include hydrocarbons (e.g. propane), carbon tetrafluoride, and noble gases such as argon and xenon. For this study, we utilized the Monte Carlo simulation code “Stopping and Range of Ions in Matter” to analyze the expected behavior of argon, xenon, carbon dioxide, difluoroethane and octafluoropropane as stopping gases for thermal neutron detectors. We also compare these findings to our previously analyzed performance of propane, butane and carbon tetrafluoride. A discussion of these gases includes their behavior in terms of proton and triton range, ionization distribution and straggle.

Comparison of various stopping gases for 3He-based position sensitive neutron detectors

Science.gov (United States)

Doumas, A.; Smith, G. C.

2012-05-01

A range of solid state, scintillator and gas based detectors are being developed for use at the next generation of high flux neutron facilities. Since gas detectors are expected to continue to play a key role in future specific thermal neutron experiments, a comparison of the performance characteristics of prospective stopping gases is beneficial. Gas detectors typically utilize the reaction 3He(n,p)t to detect thermal neutrons; the 3He gas is used in a mixture containing a particular stopping gas in order to maintain relatively short ranges for the proton and triton pair emitted from the n-3He reaction. Common stopping gases include hydrocarbons (e.g. propane), carbon tetrafluoride, and noble gases such as argon and xenon. For this study, we utilized the Monte Carlo simulation code "Stopping and Range of Ions in Matter" to analyze the expected behavior of argon, xenon, carbon dioxide, difluoroethane and octafluoropropane as stopping gases for thermal neutron detectors. We also compare these findings to our previously analyzed performance of propane, butane and carbon tetrafluoride. A discussion of these gases includes their behavior in terms of proton and triton range, ionization distribution and straggle.

A Detector for (n,gamma) Cross Section Measurements

Energy Technology Data Exchange (ETDEWEB)

Hellstroem, J; Beshai, S

1971-09-15

A new detector to be used for determining total (n,gamma) cross sections has been developed in this laboratory. The detector is a large liquid scintillator of approximately 4pi geometry. When used in an experiment the overall time resolution was found to be 10 ns

Noble metal catalysts in the production of biofuels

Energy Technology Data Exchange (ETDEWEB)

Gutierrez, A.

2013-11-01

The energy demand is increasing in the world together with the need to ensure energy security and the desire to decrease greenhouse gas emissions. While several renewable alternatives are available for the production of electricity, e.g. solar energy, wind power, and hydrogen, biomass is the only renewable source that can meet the demand for carbon-based liquid fuels and chemicals. The technology applied in the conversion of biomass depends on the type and complexity of the biomass, and the desired fuel. Hydrogen and hydrogen-rich mixtures (synthesis gas) are promising energy sources as they are more efficient and cleaner than existing fuels, especially when they are used in fuel cells. Hydrotreatment is a catalytic process that can be used in the conversion of biomass or biomass-derived liquids into fuels. In autothermal reforming (ATR), catalysts are used in the production of hydrogen-rich mixtures from conventional fuels or bio-fuels. The different nature of biomass and biomass-derived liquids and mineral oil makes the use of catalysts developed for the petroleum industry challenging. This requires the improvement of available catalysts and the development of new ones. To overcome the limitations of conventional hydrotreatment and ATR catalysts, zirconia-supported mono- and bimetallic rhodium, palladium, and platinum catalysts were developed and tested in the upgrading of model compounds for wood-based pyrolysis oil and in the production of hydrogen, using model compounds for gasoline and diesel. Catalysts were also tested in the ATR of ethanol. For comparative purposes commercial catalysts were tested and the results obtained with model compounds were compared with those obtained with real feedstocks (hydrotreatmet tests with wood-based pyrolysis oil and ATR tests with NExBTL renewable diesel). Noble metal catalysts were active and selective in the hydrotreatment of guaiacol used as the model compound for the lignin fraction of wood-based pyrolysis oil and wood

The effects of Basel III liquidity regulations on banks’ profitability

Directory of Open Access Journals (Sweden)

Tafirei Mashamba

2018-05-01

Full Text Available The new Basel III Liquidity Coverage Ratio standard which encourages banks to maintain a diversified pool of high-quality liquid assets against their short-term expected net cash outflows although it appears to be noble from a theoretic perspective it may weigh down banks’ performance because liquid assets earn low returns. It is against this background that this study sought to evaluate the impact of the new Basel III liquidity regulations on the profitability of banks in emerging market economies. A sample of 40 banks operating in 11 emerging markets over the period 2011 to 2016 was used in the study. For estimation, system Generalized Method of Moments (GMM estimator was employed. Surprisingly, empirical results demonstrated that regulatory pressure stemming from Liquidity Coverage Ratio requirement increased instead of diminishing the profitability of banks in emerging markets. The plausible explanation given for this evidence was that banks in emerging markets managed their liquidity in a manner that is consistent with Liquidity Coverage Ratio rule hence the regulation had no detrimental effects on banks in emerging economies.

Cherenkov Water Detectors in Particle Physics and Cosmic Rays

Science.gov (United States)

Petrukhin, A. A.; Yashin, I. I.

2017-12-01

Among various types of Cherenkov detectors (solid, liquid and gaseous) created for different studies, the most impressive development was gained by water detectors: from the first detector with a volume of several liters in which the Cherenkov radiation was discovered, to the IceCube detector with a volume of one cubic kilometer. The review of the development of Cherenkov water detectors for various purposes and having different locations - ground-based, underground and underwater-is presented in the paper. The prospects of their further development are also discussed.

A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

KAUST Repository

Jin, Zhao; Xiao, Manda; Bao, Zhihong; Wang, Peng; Wang, Jianfang

2012-01-01

Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

KAUST Repository

Jin, Zhao

2012-04-26

Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and characterisation of superheated drop detectors

International Nuclear Information System (INIS)

Krishnamoorthy, P.

1989-01-01

Basic mechanism of bubble nucleation in superheated drops with respect to minimum energy of radiation and temperature is discussed. Experimental details and techniques for the preparation of Superheated Drop Detectors (SDDs) is explained. For the sample preparation, homogeneous composition of polymer (Morarfloc) and glycerine was used as the host medium and three different refrigerants Mafron-21, Mafron-12 and Mafron-11/12 (50:50) were chosen as the sensitive liquids. A pressure reactor developed at Health and Safety Laboratory is used for dispersing the sensitive liquid drops in the homogeneous composition under pressure. Some of the imporatant detector characteristics were studied. (author). 26 refs., 9 figs., 1 tab

Properties and application of noble metal catalysts for heterogeneous catalytic hydrogenations

Energy Technology Data Exchange (ETDEWEB)

Horn, G; Frohning, C D; Cornils, B [Ruhrchemie A.G., Oberhausen (Germany, F.R.)

1976-07-01

The special properties of the six platinum group elements - ruthenium, rhodium, palladium, osmium, iridium, platinum - make them useful as active metals for catalytic reactions. Especially valuable is their property of favouring a single reaction even when the possibility of a number of parallel reactions exists under certain reaction conditions. This selectivity of the noble metal catalyst may be directed or enhanced through appropriate choise of the metal, the reaction conditions, the duration of the reaction, the amount of hydrogen etc. Even the physical state of the catalyst - supported or unsupported - is of influence when using noble metal catalysts as described in this report.

Fluorescence emissions from mixtures of Hg with the noble gases

International Nuclear Information System (INIS)

Woodworth, J.R.

1977-01-01

Fluorescence emissions from mixtures of Hg with high pressure Xe, Kr, and Ar (approx.1 torr Hg, 10 3 --10 4 torr noble gas) have been studied using a short-pulse relativistic electron beam as an excitation source. Hg--noble gas molecular bands were observed on the red sides of the Hg lines (1849 and 2537 A) as well as on the red sides of the Hg visible lines (7 3 S 1 →6 3 P 0 , 1 , 2 ). Temporal histories and production efficiencies of the molecular emissions were determined and a model was formulated for the time histories of the HgXe 2600 A bands. Possible applications to high power laser systems are discussed

Vitrification of noble metals containing NCAW simulant with an engineering scale melter (ESM): Campaign report

Energy Technology Data Exchange (ETDEWEB)

Grunewald, W.; Roth, G.; Tobie, W.; Weisenburger, S.; Weiss, K.; Elliott, M.; Eyler, L.L.

1996-03-01

ESM has been designed as a 10th-scale model of the DWPF-type melter, currently the reference melter for nitrification of Hanford double shell tankwaste. ESM and related equipment have been integrated to the existing mockup vitrification plant VA-WAK at KfK. On June 2-July 10, 1992, a shakedown test using 2.61 m{sup 3} of NCAW (neutralized current acid waste) simulant without noble metals was performed. On July 11-Aug. 30, 1992, 14.23 m{sup 3} of the same simulant with nominal concentrations of Ru, Rh, and Pd were vitrified. Objective was to investigate the behavior of such a melter with respect to discharge of noble metals with routine glass pouring via glass overflow. Results indicate an accumulation of noble metals in the bottom area of the flat-bottomed ESM. About 65 wt% of the noble metals fed to the melter could be drained out, whereas 35 wt% accumulated in the melter, based on analysis of glass samples from glass pouring stream in to the canisters. After the melter was drained at the end of the campaign through a bottom drain valve, glass samples were taken from the residual bottom layer. The samples had significantly increased noble metals content (factor of 20-45 to target loading). They showed also a significant decrease of the specific electric resistance compared to bulk glass (factor of 10). A decrease of 10- 15% of the resistance between he power electrodes could be seen at the run end, but the total amount of noble metals accumulated was not yet sufficient enough to disturb the Joule heating of the glass tank severely.

On the applicability of nearly free electron model for resistivity calculations in liquid metals

International Nuclear Information System (INIS)

Gorecki, J.; Popielawski, J.

1982-09-01

The calculations of resistivity based on the nearly free electron model are presented for many noble and transition liquid metals. The triple ion correlation is included in resistivity formula according to SCQCA approximation. Two different methods for describing the conduction band are used. The problem of applicability of the nearly free electron model for different metals is discussed. (author)

Partitioning of krypton-85 in liquid scintillation cocktail

International Nuclear Information System (INIS)

Hohorst, F.A.; Sherlock, M.A.

1994-12-01

Krypton is one of the noble gases. As such, it forms compounds only with exceptionally strong oxidizing agents. The concentration of krypton in air is 1.139 parts per million by volume. In general, its behavior is best described as that of an ideal gas. Krypton-85 is the longest lived of the common radioactive noble gases with a half life of 10.72 years. Gamma radiation at 513.990 keV has an intensity of only 0.434%. Most decay is β - emission with a maximum energy of 687.0 keV and an average energy of 251.4 keV. The analytical chemistry of krypton-85 is driven by these factors. High concentrations may be gamma counted directly. Low levels are typically determined by more sensitive techniques such as liquid scintillation counting (LSC) where detection limits on the order of 1 picocurie (pCi) are routinely achieved. For a 5 standard cubic centimeter (scc) sample, this represents a concentration of 0.2 pCi/scc, well below the DOE Air Immersion Derived Concentration Guideline (G) of 3 pCi/scc. As a gas, krypton in a sealed LSC vial distributes itself between the liquid phase and the gas phase. Some past work has used gamma counting at levels many orders of magnitude greater than those now achievable by LSC to study the distribution of krypton. This effect is of interest in the analytical chemistry of krypton-85 because geometrical considerations influence how much of the material in the gas phase decays generating particles which then impact the liquid phase where they may be counted

Noble metal behavior during melting of simulated high-level nuclear waste glass feeds

International Nuclear Information System (INIS)

Anderson, L.D.; Dennis, T.; Elliott, M.L.; Hrma, P.

1993-04-01

Noble metals and their oxides can settle in waste glass melters and cause electrical shorting. Simulated waste feeds from Hanford, Savannah River, and Germany were heat treated for 1 hour in a gradient furnace at temperatures ranging from approximately 600 degrees C--1000 degrees C and examined by electron microscopy to determine shapes, sizes, and distribution of noble metal particles as a function of temperature. Individual noble metal particles and agglomerates of rhodium (Rh), ruthenium (RuO 2 ), and palladium (Pd), as well as their alloys, were seen. the majority of particles and agglomerates were generally less than 10 microns; however, large agglomerations (up to 1 mm) were found in the German feed. Detailed particle distribution and characterization was performed for a Hanford waste to provide input to computer modeling of particle settling in the melter

Calibration factor determination for solid nuclear track detectors CR-39 type exposed to Rn-222

International Nuclear Information System (INIS)

Cazula, Camila Dias; Campos, Marcia Pires de; Mazzilli, Barbara Paci

2014-01-01

In the detection method with solid nuclear track detector, when a heavy particle rests on the detector surface, causes a breakdown in their molecular structure forming a trace. One of the typical applications of these detectors is the measurement of the concentration of Rn -222 in air, a noble radioactive gas, part of the U-238 series, emitting alpha particles and important in epidemiological studies to protect individuals from natural radiation. To determine the concentration of Rn -222 in the air in a room is necessary to know the density of lines (traces / cm 2 ) on the detector surface, the exposure time and the calibration factor. The determination of the calibration factor for CR-39 detectors was taken from the exposure of these to a known concentration of Rn-222. Therefore, the detectors were placed inside a cell of Lucas adapted and subsequently exposed to a concentration of Rn-222 15 kBq / m 3 , by means of the apparatus RN-150 Pylon Electronics Incorporation, which has a source of Ra-226 and releases known concentrations of Rn-222. Six calibration factor determinations were performed, the average value obtained was 0.0534 ±0.0021 (traces / cm 2 per Bq / m 3 day). The results are consistent with literature values for the same type of detector and showed good reproducibility

ArCLight—A Compact Dielectric Large-Area Photon Detector

Directory of Open Access Journals (Sweden)

Martin Auger

2018-02-01

Full Text Available ArgonCube Light readout system (ArCLight is a novel device for detecting scintillation light over large areas with Photon Detection Efficiency (PDE of the order of a few percent. Its robust technological design allows for efficient use in large-volume particle detectors, such as Liquid Argon Time Projection Chambers (LArTPCs or liquid scintillator detectors. Due to its dielectric structure it can be placed inside volumes with high electric field. It could potentially replace vacuum PhotoMultiplier Tubes (PMTs in applications where high PDE is not required. The photon detection efficiency for a 10 × 10 cm2 detector prototype was measured to be in the range of 0.8% to 2.2% across the active area.

Growth responses of Neurospora crassa to increased partial pressures of the noble gases and nitrogen.

Science.gov (United States)

Buchheit, R G; Schreiner, H R; Doebbler, G F

1966-02-01

Buchheit, R. G. (Union Carbide Corp., Tonawanda, N.Y.), H. R. Schreiner, and G. F. Doebbler. Growth responses of Neurospora crassa to increased partial pressures of the noble gases and nitrogen. J. Bacteriol. 91:622-627. 1966.-Growth rate of the fungus Neurospora crassa depends in part on the nature of metabolically "inert gas" present in its environment. At high partial pressures, the noble gas elements (helium, neon, argon, krypton, and xenon) inhibit growth in the order: Xe > Kr> Ar > Ne > He. Nitrogen (N(2)) closely resembles He in inhibitory effectiveness. Partial pressures required for 50% inhibition of growth were: Xe (0.8 atm), Kr (1.6 atm), Ar (3.8 atm), Ne (35 atm), and He ( approximately 300 atm). With respect to inhibition of growth, the noble gases and N(2) differ qualitatively and quantitatively from the order of effectiveness found with other biological effects, i.e., narcosis, inhibition of insect development, depression of O(2)-dependent radiation sensitivity, and effects on tissue-slice glycolysis and respiration. Partial pressures giving 50% inhibition of N. crassa growth parallel various physical properties (i.e., solubilities, solubility ratios, etc.) of the noble gases. Linear correlation of 50% inhibition pressures to the polarizability and of the logarithm of pressure to the first and second ionization potentials suggests the involvement of weak intermolecular interactions or charge-transfer in the biological activity of the noble gases.

Photoelectron spectrometer for attosecond spectroscopy of liquids and gases

Energy Technology Data Exchange (ETDEWEB)

Jordan, I.; Huppert, M.; Wörner, H. J., E-mail: hwoerner@ethz.ch [Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich (Switzerland); Brown, M. A. [Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, 8093 Zurich (Switzerland); Bokhoven, J. A. van [Institute for Chemical and Bioengineering, ETH Zurich, Vladimir-Prelog-Weg 1, 8093 Zurich (Switzerland); Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institute, 5232 Villigen (Switzerland)

2015-12-15

A new apparatus for attosecond time-resolved photoelectron spectroscopy of liquids and gases is described. It combines a liquid microjet source with a magnetic-bottle photoelectron spectrometer and an actively stabilized attosecond beamline. The photoelectron spectrometer permits venting and pumping of the interaction chamber without affecting the low pressure in the flight tube. This pressure separation has been realized through a sliding skimmer plate, which effectively seals the flight tube in its closed position and functions as a differential pumping stage in its open position. A high-harmonic photon spectrometer, attached to the photoelectron spectrometer, exit port is used to acquire photon spectra for calibration purposes. Attosecond pulse trains have been used to record photoelectron spectra of noble gases, water in the gas and liquid states as well as solvated species. RABBIT scans demonstrate the attosecond resolution of this setup.

Photoelectron spectrometer for attosecond spectroscopy of liquids and gases

International Nuclear Information System (INIS)

Jordan, I.; Huppert, M.; Wörner, H. J.; Brown, M. A.; Bokhoven, J. A. van

2015-01-01

A new apparatus for attosecond time-resolved photoelectron spectroscopy of liquids and gases is described. It combines a liquid microjet source with a magnetic-bottle photoelectron spectrometer and an actively stabilized attosecond beamline. The photoelectron spectrometer permits venting and pumping of the interaction chamber without affecting the low pressure in the flight tube. This pressure separation has been realized through a sliding skimmer plate, which effectively seals the flight tube in its closed position and functions as a differential pumping stage in its open position. A high-harmonic photon spectrometer, attached to the photoelectron spectrometer, exit port is used to acquire photon spectra for calibration purposes. Attosecond pulse trains have been used to record photoelectron spectra of noble gases, water in the gas and liquid states as well as solvated species. RABBIT scans demonstrate the attosecond resolution of this setup

Photoelectron spectrometer for attosecond spectroscopy of liquids and gases

Science.gov (United States)

Jordan, I.; Huppert, M.; Brown, M. A.; van Bokhoven, J. A.; Wörner, H. J.

2015-12-01

A new apparatus for attosecond time-resolved photoelectron spectroscopy of liquids and gases is described. It combines a liquid microjet source with a magnetic-bottle photoelectron spectrometer and an actively stabilized attosecond beamline. The photoelectron spectrometer permits venting and pumping of the interaction chamber without affecting the low pressure in the flight tube. This pressure separation has been realized through a sliding skimmer plate, which effectively seals the flight tube in its closed position and functions as a differential pumping stage in its open position. A high-harmonic photon spectrometer, attached to the photoelectron spectrometer, exit port is used to acquire photon spectra for calibration purposes. Attosecond pulse trains have been used to record photoelectron spectra of noble gases, water in the gas and liquid states as well as solvated species. RABBIT scans demonstrate the attosecond resolution of this setup.

Non-noble metal based electro-catalyst compositions for proton exchange membrane based water electrolysis and methods of making

Science.gov (United States)

Kumta, Prashant N.; Kadakia, Karan Sandeep; Datta, Moni Kanchan; Velikokhatnyi, Oleg

2017-02-07

The invention provides electro-catalyst compositions for an anode electrode of a proton exchange membrane-based water electrolysis system. The compositions include a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof, and a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, cooper oxide, zirconium oxide, nickel oxide and mixtures thereof. Further, the non-noble metal component can include a dopant. The dopant can be at least one element selected from Groups III, V, VI and VII of the Periodic Table. The compositions can be prepared using a surfactant approach or a sol gel approach. Further, the compositions are prepared using noble metal and non-noble metal precursors. Furthermore, a thin film containing the compositions can be deposited onto a substrate to form the anode electrode.

Tracing enhanced oil recovery signatures in casing gases from the Lost Hills oil field using noble gases

Science.gov (United States)

Barry, Peter H.; Kulongoski, Justin; Landon, Matthew K.; Tyne, R.L.; Gillespie, Janice; Stephens, Michael; Hillegonds, D.J.; Byrne, D.J.; Ballentine, C.J.

2018-01-01

Enhanced oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however the environmental impacts of such practices remain poorly understood. EOR is particularly prevalent in oil fields throughout California where water resources are in high demand and disposal of high volumes of produced water may affect groundwater quality. Consequently, it is essential to better understand the fate of injected (EOR) fluids in California and other subsurface petroleum systems, as well as any potential effect on nearby aquifer systems. Noble gases can be used as tracers to understand hydrocarbon generation, migration, and storage conditions, as well as the relative proportions of oil and water present in the subsurface. In addition, a noble gas signature diagnostic of injected (EOR) fluids can be readily identified. We report noble gas isotope and concentration data in casing gases from oil production wells in the Lost Hills oil field, northwest of Bakersfield, California, and injectate gas data from the Fruitvale oil field, located within the city of Bakersfield. Casing and injectate gas data are used to: 1) establish pristine hydrocarbon noble-gas signatures and the processes controlling noble gas distributions, 2) characterize the noble gas signature of injectate fluids, 3) trace injectate fluids in the subsurface, and 4) construct a model to estimate EOR efficiency. Noble gas results range from pristine to significantly modified by EOR, and can be best explained using a solubility exchange model between oil and connate/formation fluids, followed by gas exsolution upon production. This model is sensitive to oil-water interaction during hydrocarbon expulsion, migration, and storage at reservoir conditions, as well as any subsequent modification by EOR.

Recovery of Mercury From Contaminated Liquid Wastes

International Nuclear Information System (INIS)

1998-01-01

The Base Contract program emphasized the manufacture and testing of superior sorbents for mercury removal, testing of the sorption process at a DOE site, and determination of the regeneration conditions in the laboratory. During this project, ADA Technologies, Inc. demonstrated the following key elements of a successful regenerable mercury sorption process: (1) sorbents that have a high capacity for dissolved, ionic mercury; (2) removal of ionic mercury at greater than 99% efficiency; and (3) thermal regeneration of the spent sorbent. ADA's process is based on the highly efficient and selective sorption of mercury by noble metals. Contaminated liquid flows through two packed columns that contain microporous sorbent particles on which a noble metal has been finely dispersed. A third column is held in reserve. When the sorbent is loaded with mercury to the point of breakthrough at the outlet of the second column, the first column is taken off-line and the flow of contaminated liquid is switched to the second and third columns. The spent column is regenerated by heating. A small flow of purge gas carries the desorbed mercury to a capture unit where the liquid mercury is recovered. Laboratory-scale tests with mercuric chloride solutions demonstrated the sorbents' ability to remove mercury from contaminated wastewater. Isotherms on surrogate wastes from DOE's Y-12 Plant in Oak Ridge, Tennessee showed greater than 99.9% mercury removal. Laboratory- and pilot-scale tests on actual Y-12 Plant wastes were also successful. Mercury concentrations were reduced to less than 1 ppt from a starting concentration of 1,000 ppt. The treatment objective was 50 ppt. The sorption unit showed 10 ppt discharge after six months. Laboratory-scale tests demonstrated the feasibility of sorbent regeneration. Results show that sorption behavior is not affected after four cycles

Comparison of various stopping gases for {sup 3}He-based position sensitive neutron detectors

Energy Technology Data Exchange (ETDEWEB)

Doumas, A. [United States Merchant Marine Academy, Steamboat Road, Kings Point, NY 11024 (United States); Smith, G.C., E-mail: gsmith@bnl.gov [Instrumentation Division, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2012-05-21

A range of solid state, scintillator and gas based detectors are being developed for use at the next generation of high flux neutron facilities. Since gas detectors are expected to continue to play a key role in future specific thermal neutron experiments, a comparison of the performance characteristics of prospective stopping gases is beneficial. Gas detectors typically utilize the reaction {sup 3}He(n,p)t to detect thermal neutrons; the {sup 3}He gas is used in a mixture containing a particular stopping gas in order to maintain relatively short ranges for the proton and triton pair emitted from the n-{sup 3}He reaction. Common stopping gases include hydrocarbons (e.g. propane), carbon tetrafluoride, and noble gases such as argon and xenon. For this study, we utilized the Monte Carlo simulation code 'Stopping and Range of Ions in Matter' to analyze the expected behavior of argon, xenon, carbon dioxide, difluoroethane and octafluoropropane as stopping gases for thermal neutron detectors. We also compare these findings to our previously analyzed performance of propane, butane and carbon tetrafluoride. A discussion of these gases includes their behavior in terms of proton and triton range, ionization distribution and straggle.

Paleotemperatures derived from noble gases dissolved in groundwater and in relation to soil temperature

International Nuclear Information System (INIS)

Stute, M.; Sonntag, C.

1992-01-01

Measurements of He, Ne, Ar, Kr and Xe dissolved in groundwater at two sites (Bocholt, Germany, and the Great Hungarian Plain) were taken to prove the reliability of noble gas temperatures as indicators of paleotemperatures. Noble gas temperatures of groundwater of Holocene age were found to reflect the annual mean soil temperature in the recharge are with an accuracy close to the precision of measurement (1σ approx. ±0.5 deg. C). Noble gas temperature data demonstrate the influence of vegetation cover on the soil temperature in the infiltration area. Groundwater formed in forests at the Bocholt site shows noble gas temperatures that are 2.2 deg. C lower than the groundwater formed in fields or meadows. The temperature data obtained from groundwater of the Great Hungarian Plain for the last glaciation are ≥ 8.6 deg. C lower than data from recent groundwater for maximum glaciation (approx. 18,000 years ago) and 4.7 ± 1 deg. C lower for the preceding interstadial (approx. 28,000-35,000 years ago). These data permit independent reconstruction of paleoclimatic conditions. (author). 19 refs, 3 figs, 1 tab

The Role of Noble Metal Addition Methods on BWR Shut Down Dose Rates

International Nuclear Information System (INIS)

Cowan, Robert L.; Garcia Susan, E.

2012-09-01

Noble metal addition technology was developed for the BWR as a means of establishing low electrochemical corrosion potentials (ECP) on structural materials to mitigate intergranular stress corrosion cracking (IGSCC). When the reactor water molar ratio of H 2 / (O 2 +H 2 O 2 ) is > 2 on noble metal treated surfaces, the resulting ECP is near -500 mV (SHE), well into the mitigation range. This ratio can be achieved in most areas of the reactor with feedwater hydrogen additions in the range of 0.2 mg/kg, a condition that does not increase the radiation level in the main steam, a side effect of conventional hydrogen water chemistry (HWC). The resulting low ECP on the surface of stainless steel piping and components results in a change in form of the stable corrosion film to a spinel structure. Since it is the 60 Co incorporated into the corrosion film that is the primary source term of shutdown dose rates in BWRs, the structure and composition of the film can have a large influence in the resulting dose rates. The results of the first generation of noble metal technology, noble metal chemical addition (NMCA), showed that the reactor water ratio of 60 Co (s)/Zn (s) was a key parameter in determining shut down dose rate values. This paper will review that history and provide mechanistic understanding of how initial post NMCA dose rates are established and change with time. On-line noble metal chemical addition (OLNC) is the second generation of noble metal technology. The method utilizes the on-line injection of dilute Na 2 Pt (OH) 6 into the feedwater over a period of approximately 10 days. The first application of OLNC occurred at a European reactor in July of 2005 and to date over 20 BWRs have applied the technology, with many more applications scheduled. It is expected that OLNC will become the de facto standard because it eliminates 60 hours of outage application time and it addresses the crack flanking concerns that can arise under certain conditions. Because both

Lepton detector workshop summary

International Nuclear Information System (INIS)

Imlay, R.; Iwata, S.; Jacobs, S.

1976-01-01

A discussion is given of the initial detector design, focusing on the cost estimates and on the inner detector modules. With regard to inner modules, the rate problem was examined for the closest elements, and the question whether one should use argon or lead-liquid scintillator calorimeters was discussed. New designs which involved major modifications to the lepton detector are considered. The major motivations for alternative designs were twofold. One was that the original detector looked quite expensive, and a study of the tradeoff of money versus physics had not really been done yet. The second point was that, since the physics region to be explored was totally new ground, one would like to leave as many options open as possible and build a detector that was as flexible as possible. A scaled-down version of the original design, which was strongly favored by this study, appears to save an appreciable amount of money with a small decrease in the initial physics scope. The more modular designs seem quite attractive, but not enough time was spent to demonstrate feasibility

Large volume cryogenic silicon detectors

International Nuclear Information System (INIS)

Braggio, C.; Boscardin, M.; Bressi, G.; Carugno, G.; Corti, D.; Galeazzi, G.; Zorzi, N.

2009-01-01

We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm 3 , cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

Nanophosphor composite scintillator with a liquid matrix

Science.gov (United States)

McKigney, Edward Allen; Burrell, Anthony Keiran; Bennett, Bryan L.; Cooke, David Wayne; Ott, Kevin Curtis; Bacrania, Minesh Kantilal; Del Sesto, Rico Emilio; Gilbertson, Robert David; Muenchausen, Ross Edward; McCleskey, Thomas Mark

2010-03-16

An improved nanophosphor scintillator liquid comprises nanophosphor particles in a liquid matrix. The nanophosphor particles are optionally surface modified with an organic ligand. The surface modified nanophosphor particle is essentially surface charge neutral, thereby preventing agglomeration of the nanophosphor particles during dispersion in a liquid scintillator matrix. The improved nanophosphor scintillator liquid may be used in any conventional liquid scintillator application, including in a radiation detector.

Nanoparticles of noble metals in the supergene zone

Science.gov (United States)

Zhmodik, S. M.; Kalinin, Yu. A.; Roslyakov, N. A.; Mironov, A. G.; Mikhlin, Yu. L.; Belyanin, D. K.; Nemirovskaya, N. A.; Spiridonov, A. M.; Nesterenko, G. V.; Airiyants, E. V.; Moroz, T. N.; Bul'bak, T. A.

2012-04-01

Formation of noble metal nanoparticles is related to various geological processes in the supergene zone. Dispersed mineral phases appear during weathering of rocks with active participation of microorganisms, formation of soil, in aqueous medium and atmosphere. Invisible gold and other noble metals are incorporated into oxides, hydroxides, and sulfides, as well as in dispersed organic and inorganic carbonic matter. Sulfide minerals that occur in bedrocks and ores unaltered by exogenic processes and in cementation zone are among the main concentrators of noble metal nanoparticles. The ability of gold particles to disaggregate is well-known and creates problems in technological and analytical practice. When Au and PGE nanoparticles and clusters occur, these problems are augmented because of their unusual reactions and physicochemical properties. The studied gold, magnetite, titanomagnetite and pyrite microspherules from cementation zone and clay minerals of laterites in Republic of Guinea widen the knowledge of their abundance and inferred formation conditions, in particular, in the contemporary supergene zone. Morphology and composition of micrometer-sized Au mineral spherules were studied with SEM and laser microprobe. The newly formed segregations of secondary gold on the surface of its residual grains were also an object of investigation. The character of such overgrowths is the most indicative for nanoparticles. The newly formed Au particles provide evidence for redistribution of ultradispersed gold during weathering. There are serious prerequisites to state that microorganisms substantially control unusual nano-sized microspherical morphology of gold particles in the supergene zone. This is supported by experiments indicating active absorption of gold by microorganisms and direct evidence for participation of Ralstonia metallidurans bacteria in the formation of peculiar corroded bacteriomorphic surface of gold grains. In addition, the areas enriched in carbon

The Behavior and Effects of the Noble Metals in the DWPF Melter System

International Nuclear Information System (INIS)

Smith, M.E.; Bickford, D.F.

1997-01-01

Governments worldwide have committed to stabilization of high-level nuclear waste (HLW) by vitrification to a durable glass form for permanent disposal. All of these nuclear wastes contain the fission-product noble metals: ruthenium, rhodium, and palladium. SRS wastes also contain natural silver from iodine scrubbers. Closely associated with the noble metals are the fission products selenium and tellurium which are chemical analogs of sulfur and which combine with noble metals to influence their behavior and properties. Experience has shown that these melt insoluble metals and their compounds tend to settle to the floor of Joule-heated ceramic melters. In fact, almost all of the major research and production facilities have experienced some operational problem which can be associated with the presence of dense accumulations of these relatively conductive metals and/or their compounds. In most cases, these deposits have led to a loss of production capability, in some cases, to the point that melter operation could not continue. HLW nuclear waste vitrification facilities in the United States are the Department of Energy's Defense Waste Processing Facility (DWPF) at the Savannah River Site, the planned Hanford Waste Vitrification Plant (HWVP) at the Hanford Site and the operating West Valley Demonstration Project (WVDP) at West Valley, NY. The Integrated DWPF Melter System (IDMS) is a vitrification test facility at the Savannah River Technology Center (SRTC). It was designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas treatment systems. An extensive noble metals testing program was begun in 1990. The objectives of this task were to explore the effects of the noble metals on the DWPF melter feed preparation and waste vitrification processes. This report focuses on the vitrification portion of the test program

Compendium of Instrumentation Whitepapers on Frontier Physics Needs for Snowmass 2013

Energy Technology Data Exchange (ETDEWEB)

Lipton, R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

2013-01-01

Contents of collection of whitepapers include: Operation of Collider Experiments at High Luminosity; Level 1 Track Triggers at HL-LHC; Tracking and Vertex Detectors for a Muon Collider; Triggers for hadron colliders at the energy frontier; ATLAS Upgrade Instrumentation; Instrumentation for the Energy Frontier; Particle Flow Calorimetry for CMS; Noble Liquid Calorimeters; Hadronic dual-readout calorimetry for high energy colliders; Another Detector for the International Linear Collider; e+e- Linear Colliders Detector Requirements and Limitations; Electromagnetic Calorimetry in Project X Experiments The Project X Physics Study; Intensity Frontier Instrumentation; Project X Physics Study Calorimetry Report; Project X Physics Study Tracking Report; The LHCb Upgrade; Neutrino Detectors Working Group Summary; Advanced Water Cherenkov R&D for WATCHMAN; Liquid Argon Time Projection Chamber (LArTPC); Liquid Scintillator Instrumentation for Physics Frontiers; A readout architecture for 100,000 pixel Microwave Kinetic In- ductance Detector array; Instrumentation for New Measurements of the Cosmic Microwave Background polarization; Future Atmospheric and Water Cherenkov ?-ray Detectors; Dark Energy; Can Columnar Recombination Provide Directional Sensitivity in WIMP Search?; Instrumentation Needs for Detection of Ultra-high Energy Neu- trinos; Low Background Materials for Direct Detection of Dark Matter; Physics Motivation for WIMP Dark Matter Directional Detection; Solid Xenon R&D at Fermilab; Ultra High Energy Neutrinos; Instrumentation Frontier: Direct Detection of WIMPs; nEXO detector R&D; Large Arrays of Air Cherenkov Detectors; and Applications of Laser Interferometry in Fundamental Physics Experiments.

Noble metal abundances in komatiite suites from Alexo, Ontario and Gorgona Island, Colombia

Science.gov (United States)

Brügmann, G. E.; Arndt, N. T.; Hofmann, A. W.; Tobschall, H. J.

1987-08-01

The distribution of the chalcophile and siderophile metals Cu, Ni, Au, Pd, Ir, Os and Ru in an Archaean komatiite flow from Alexo, Ontario and in a Phanerozoic komatiitic suite of Gorgona Island, Colombia, provides new information about the geochemical behaviour of these elements. Copper, Au and Pd behave as incompatible elements during the crystallization of these ultramafic magmas. In contrast, Ni, Ir, Os and Ru concentrations systematically decrease with decreasing MgO contents, a pattern characteristic of compatible elements. These trends are most probably controlled by olivine crystallization, which implies that Ir, Os and Ru are compatible in olivine. Calculated partition coefficients for Ir, Os and Ru between olivine and the melt are about 1.8. Compared to primitive mantle, parental komatiitic liquids are enriched in (incompatible) Cu, Au and Pd and depleted in (compatible) Ir, Os and Ru. Within both Archaean and Phanerozoic komatiites, noble metal ratios such as Au/Pd, Ir/Os, Os/Ru and Ru/Ir and ratios of lithophile and siderophile elements such as Ti/Pd, Ti/Au are constant and similar to primitive mantle values. This implies that Au and Pd are moderately incompatible elements and that there has been no significant fractionation of siderophile and lithophile elements since the Archaean. Platinum-group element abundances of normal MORB are highly variable and always much lower than in komatiites, because MORB magma is saturated with sulfur and a variable but minor amount of sulfide segregated during mantle melting or during the ascent of magma to the surface. Sulfide deposits associated with komatiites display similar chalcophile element patterns to those of komatiites. Noble metal ratios such as Pd/Ir, Au/Ir, Pd/Os and Pd/Ru can be used to determine the composition of the host komatiite at the time of sulfide segregation.

Aroma compounds and characteristics of noble-rot wines of Chardonnay grapes artificially botrytized in the vineyard.

Science.gov (United States)

Wang, Xing-Jie; Tao, Yong-Sheng; Wu, Yun; An, Rong-Yan; Yue, Zhuo-Ya

2017-07-01

Aroma characteristics and their impact volatile components of noble-rot wines elaborated from artificial botrytized Chardonnay grapes, obtained by spraying Botrytis cinerea suspension in Yuquan vineyard, Ningxia, China, were explored in this work. Dry white wine made from normal-harvested grapes and sweet wine produced from delay-harvested grapes were compared. Wine aromas were analysed by trained sensory panelists, and aroma compounds were determined by SPME-GC-MS. Results indicated that esters, fatty acids, thiols, lactones, volatile phenols and 2-nonanone increased markedly in noble-rot wines. In addition to typical aromas of noble-rot wines, artificial noble-rot wines were found to contain significant cream and dry apricot attributes. Partial Least-Squares Regression models of aroma characteristics against aroma components revealed that non-fermentative odorants were the primary contributor to dry apricot attribute, especially, thiols, C13-norisoprenoids, lactones, terpenols and phenolic acid derivatives, while cream attribute was dependent on both fermentative and non-fermentative volatile components. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of Hydrophilic Sulfur-Containing Adsorbents for Noble Metals Having Thiocarbonyl Group Based on a Methacrylate Bearing Dithiocarbonate Moieties

Directory of Open Access Journals (Sweden)

Haruki Kinemuchi

2018-01-01

Full Text Available Novel hydrophilic sulfur-containing adsorbents for noble metals were prepared by the radical terpolymerization of a methacrylate bearing dithiocarbonate moieties (DTCMMA, hydrophilic monomers, and a cross-linker. The resulting adsorbents efficiently and selectively adsorbed noble metals (Au, Ag, and Pd from various multielement aqueous solutions at room temperature owing to the thiocarbonyl group having high affinity toward noble metals. The metal adsorption by the adsorbents was proceeded by simple mixing followed by filtration. The noble metal selectivity of the adsorbent obtained from DTCMMA and N-isopropylacrylamide was higher than that of the adsorbent obtained from DTCMMA and N,N-dimethylacrylamide due to the lower nonspecific adsorption.

Analytical equation of state with three-body forces: Application to noble gases

International Nuclear Information System (INIS)

Río, Fernando del; Díaz-Herrera, Enrique; Guzmán, Orlando; Moreno-Razo, José Antonio; Ramos, J. Eloy

2013-01-01

We developed an explicit equation of state (EOS) for small non polar molecules by means of an effective two-body potential. The average effect of three-body forces was incorporated as a perturbation, which results in rescaled values for the parameters of the two-body potential. These values replace the original ones in the EOS corresponding to the two-body interaction. We applied this procedure to the heavier noble gases and used a modified Kihara function with an effective Axilrod-Teller-Muto (ATM) term to represent the two- and three-body forces. We also performed molecular dynamics simulations with two- and three-body forces. There was good agreement between predicted, simulated, and experimental thermodynamic properties of neon, argon, krypton, and xenon, up to twice the critical density and up to five times the critical temperature. In order to achieve 1% accuracy of the pressure at liquid densities, the EOS must incorporate the effect of ATM forces. The ATM factor in the rescaled two-body energy is most important at temperatures around and lower than the critical one. Nonetheless, the rescaling of two-body diameter cannot be neglected at liquid-like densities even at high temperature. This methodology can be extended straightforwardly to deal with other two- and three-body potentials. It could also be used for other nonpolar substances where a spherical two-body potential is still a reasonable coarse-grain approximation

Noble Gases in the Hamlet Meteorite (LL4)

Science.gov (United States)

Amari, S.; Sabe, Y.; Shiraishi, T.; Matsuda, J.

2014-09-01

We analyzed noble gases in a bulk sample and an HF-HCl residue of Hamlet (LL4). The Xe composition of the residue shows that no diamond is contained in the residue. The 20Ne/22Ne ratio of Hamlet Ne-Q has been determined to be 11.0 ± 0.5.

Detectors for rare events

International Nuclear Information System (INIS)

Charpak, G.

1984-01-01

This chapter discusses the possibility of combining the advantages of photographic data retrieval with the flexibility of operation of conventional gaseous or liquid detectors operated with electronic data retrieval. Possible applications of the proposed detectors to such problems as nucleon decay, neutrinoelectron interaction, and the search for magnetic monopoles are examined. Topics considered include the photography of ionization patterns, the photography of ionization tracks with the multistep avalanche chambers, and exploiting the stimulated scintillation light. Two processes which give rise to the emission of light when ionizing electrons interact in gases under the influence of an electric field are described

Large volume cryogenic silicon detectors

Energy Technology Data Exchange (ETDEWEB)

Braggio, C. [Dipartimento di Fisica, Universita di Padova, via Marzolo 8, 35131 Padova (Italy); Boscardin, M. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy); Bressi, G. [INFN sez. di Pavia, via Bassi 6, 27100 Pavia (Italy); Carugno, G.; Corti, D. [INFN sez. di Padova, via Marzolo 8, 35131 Padova (Italy); Galeazzi, G. [INFN lab. naz. Legnaro, viale dell' Universita 2, 35020 Legnaro (Italy); Zorzi, N. [Fondazione Bruno Kessler (FBK), via Sommarive 18, I-38100 Povo (Italy)

2009-12-15

We present preliminary measurements for the development of a large volume silicon detector to detect low energy and low rate energy depositions. The tested detector is a one cm-thick silicon PIN diode with an active volume of 31 cm{sup 3}, cooled to the liquid helium temperature to obtain depletion from thermally-generated free carriers. A thorough study has been done to show that effects of charge trapping during drift disappears at a bias field value of the order of 100V/cm.

Orion, a high efficiency 4π neutron detector

International Nuclear Information System (INIS)

Crema, E.; Piasecki, E.; Wang, X.M.; Doubre, H.; Galin, J.; Guerreau, D.; Pouthas, J.; Saint-Laurent, F.

1990-01-01

In intermediate energy heavy ion collisions the multiplicity of emitted neutrons is strongly connected to energy dissipation and to impact parameter. We present the 4π detector ORION, a high efficiency liquid scintillator detector which permits to get information on the multiplicity of neutrons measured event-wise and on the spatial distribution of these neutrons [fr

TiO2 structures doped with noble metals and/or graphene oxide to improve the photocatalytic degradation of dichloroacetic acid.

Science.gov (United States)

Ribao, Paula; Rivero, Maria J; Ortiz, Inmaculada

2017-05-01

Noble metals have been used to improve the photocatalytic activity of TiO 2 . Noble metal nanoparticles prevent charge recombination, facilitating electron transport due to the equilibration of the Fermi levels. Furthermore, noble metal nanoparticles show an absorption band in the visible region due to a high localized surface plasmon resonance (LSPR) effect, which contributes to additional electron movements. Moreover, systems based on graphene, titanium dioxide, and noble metals have been used, considering that graphene sheets can carry charges, thereby reducing electron-hole recombination, and can be used as substrates of atomic thickness. In this work, TiO 2 -based nanocomposites were prepared by blending TiO 2 with noble metals (Pt and Ag) and/or graphene oxide (GO). The nanocomposites were mainly characterized via transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR), Raman spectroscopy, and photocurrent analysis. Here, the photocatalytic performance of the composites was analyzed via oxidizing dichloroacetic acid (DCA) model solutions. The influence of the noble metal load on the composite and the ability of the graphene sheets to improve the photocatalytic activity were studied, and the composites doped with different noble metals were compared. The results indicated that the platinum structures show the best photocatalytic degradation, and, although the presence of graphene oxide in the composites is supposed to enhance their photocatalytic performance, graphene oxide does not always improve the photocatalytic process. Graphical abstract It is a schematic diagram. Where NM is Noble Metal and LSPR means Localized Surface Plasmon Resonance.

Integrated DWPF Melter System (IDMS) campaign report: The first two noble metals operations

International Nuclear Information System (INIS)

Hutson, N.D.; Zamecnik, J.R.; Smith, M.E.; Miller, D.H.; Ritter, J.A.

1991-01-01

The Integrated DWPF Melter System (IDMS) is designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas systems. The facility is the first pilot-scale melter system capable of processing mercury, and flowsheet levels of halides and noble metals. In order to characterize the processing of noble metals (Pd, Rh, Ru, and Ag) on a large scale, the IDMS will be operated batchstyle for at least nine feed preparation cycles. The first two of these operations are complete. The major observation to date occurred during the second run when significant amounts of hydrogen were evolved during the feed preparation cycle. The runs were conducted between June 7, 1990 and March 8, 1991. This time period included nearly six months of ''fix-up'' time when forced air purges were installed on the SRAT MFT and other feed preparation vessels to allow continued noble metals experimentation

Biomimetic Synthesis of Gelatin Polypeptide-Assisted Noble-Metal Nanoparticles and Their Interaction Study

Science.gov (United States)

Liu, Ying; Liu, Xiaoheng; Wang, Xin

2011-12-01

Herein, the generation of gold, silver, and silver-gold (Ag-Au) bimetallic nanoparticles was carried out in collagen (gelatin) solution. It first showed that the major ingredient in gelatin polypeptide, glutamic acid, acted as reducing agent to biomimetically synthesize noble metal nanoparticles at 80°C. The size of nanoparticles can be controlled not only by the mass ratio of gelatin to gold ion but also by pH of gelatin solution. Interaction between noble-metal nanoparticles and polypeptide has been investigated by TEM, UV-visible, fluorescence spectroscopy, and HNMR. This study testified that the degradation of gelatin protein could not alter the morphology of nanoparticles, but it made nanoparticles aggregated clusters array (opposing three-dimensional α-helix folding structure) into isolated nanoparticles stabilized by gelatin residues. This is a promising merit of gelatin to apply in the synthesis of nanoparticles. Therefore, gelatin protein is an excellent template for biomimetic synthesis of noble metal/bimetallic nanoparticle growth to form nanometer-sized device.

CsI calorimeter of the CMD-3 detector

International Nuclear Information System (INIS)

Aulchenko, V.M.; Bondar, A.E.; Erofeev, A.L.; Kovalenko, O.A.; Kozyrev, A.N.; Kuzmin, A.S.; Logashenko, I.B.; Razuvaev, G.P.; Ruban, A.A.; Shebalin, V.E.; Shwartz, B.A.; Talyshev, A.A.; Titov, V.M.; Yudin, Yu.V.; Epifanov, D.A.

2015-01-01

The VEPP-2000 e + e − collider has been operated at Budker Institute of Nuclear Physics since 2010. The experiments are performed with two detectors CMD-3 and SND. The calorimetry at the CMD-3 detector is based on three subsystems, two coaxial barrel calorimeters—Liquid Xenon Calorimeter and crystal CsI calorimeter, and endcap calorimeter with BGO crystals. This paper describes the CsI calorimeter of the CMD-3 detector. The calorimeter design, its electronics and calibration procedures are discussed

Element distribution and noble gas isotopic abundances in lunar meteorite Allan Hills A81005

International Nuclear Information System (INIS)

Kraehenbuehl, U.; Eugster, O.; Niedermann, S.

1986-01-01

Antarctic meteorite ALLAN HILLS A81005, an anorthositic breccia, is recognized to be of lunar origin. The noble gases in this meteorite were analyzed and found to be solar-wind implanted gases, whose absolute and relative concentrations are quite similar to those in lunar regolith samples. A sample of this meteorite was obtained for the analysis of the noble gas isotopes, including Kr(81), and for the determination of the elemental abundances. In order to better determine the volume derived from the surface correlated gases, grain size fractions were prepared. The results of the instrumental measurements of the gamma radiation are listed. From the amounts of cosmic ray produced noble gases and respective production rates, the lunar surface residence times were calculated. It was concluded that the lunar surface time is about half a billion years

Performance of the electronics for the Liquid Argon Calorimeter system of the SLC large detector

International Nuclear Information System (INIS)

Vella, E.; Abt, I.; Haller, G.M.; Honma, A.

1988-10-01

Results of performance tests on electronics for the Liquid Argon Calorimeter (LAC) for the SLD experiment at SLAC are presented. The behavior of a sub-unit called a ''tophat,'' which processes 720 detector signals, is described. The electronics consists of charge sensitive preamplifiers, analog memories, A/D converters, and associated control and readout circuitry. An internal charge injection system is used to calibrate the overall response of the devices. Linearity is better than 1% of 0--28 pC charge at the input of the amplifiers. Noise (expressed as equivalent input charge) is less than 3000 electrons at a shaping time of 4 μs, with a slope of 2600 e/sup /minus///nF. Crosstalk to adjacent channels is less than 0.5%. The power consumption at a duty cycle of 13% is 61 W. 3 refs., 7 figs

Detector LENS as a new tool for solar neutrino spectroscopy

International Nuclear Information System (INIS)

Kornoukhov, V.N.

2001-01-01

LENS detector is a low-threshold, electron-flavor specific detector for real time measurement of the solar neutrino spectrum at low energies. It is expected that 20 tons of Yb used as a neutrino target should give several hundred events per year. The basic method for implementation of the LENS detector is scintillator technique, namely a liquid scintillator doped (up to 10% in mass) with natural Yb

Shock Compression Response of the Light Noble Gases: Neon and Helium

Science.gov (United States)

Root, Seth; Shulenburger, Luke; Cochrane, Kyle; Lopez, Andrew; Shelton, Keegan; Villalva, Jose; Mattsson, Thomas

2015-06-01

Understanding material behavior at extreme conditions is important to a wide range of processes in planetary astrophysics and inertial confinement fusion. Modeling the high pressure - high temperature processes requires robust equations of state (EOS). For many materials, EOS models have been developed using low-pressure Hugoniot data. Assumptions are made to extrapolate the EOS models to Mbar pressure regimes, leading to different model behavior at extreme conditions. In this work, we examine the high pressure response of the light noble gases: neon and helium in the multi-Mbar regime. We perform a series of shock compression experiments using Sandia's Z-Machine on cryogenically cooled liquids of Ne (26 K) and He (2.2 K) to measure the Hugoniot and reshock states. In parallel, we use density functional theory methods to calculate the Hugoniot and reshock states. The experiments validated the DFT simulations and the combined experimental and simulation results are used to assess the EOS models. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Securities Administration under Contract No. DE-AC04-94AL85000.

Visual detection of gas shows from coal core and cuttings using liquid leak detector

Energy Technology Data Exchange (ETDEWEB)

Barker, C.E. [United States Geological Survey, Denver, CO (United States)

2006-09-15

Coal core descriptions are difficult to obtain, as they must be obtained immediately after the core is retrieved and before the core is closed in a canister. This paper described a method of marking gas shows on a core surface by coating the core with a water-based liquid leak detector and photographing the subsequent foam developed on the core surface while the core is still in the core tray. Coals from a borehole at the Yukon Flats Basin in Alaska and the Maverick Basin in Texas were used to illustrate the method. Drilling mud and debris were removed from the coal samples before the leak detector solution was applied onto the core surfaces. A white froth or dripping foam developed rapidly at gas shows on the sample surfaces. A hand-held lens and a binocular microscope were used to magnify the foaming action. It was noted that foaming was not continuous across the core surface, but was restricted to localized points along the surface. It was suggested that the localized point foaming may have resulted from the coring process. However, the same tendency toward point gas show across the sample surface was found in some hard, well-indurated samples that still had undisturbed bedding and other sedimentary structures. It was concluded that gas shows marked as separate foam centres may indicate a real condition of local permeability paths. Results suggested that the new gas show detection method could be used in core selection studies to reduce the costs of exploration programs. 6 refs., 4 figs.

Cryogenic Tracking Detectors

CERN Multimedia

Luukka, P R; Tuominen, E M; Mikuz, M

2002-01-01

The recent advances in Si and diamond detector technology give hope of a simple solution to the radiation hardness problem for vertex trackers at the LHC. In particular, we have recently demonstrated that operating a heavily irradiated Si detector at liquid nitrogen (LN$_2$) temperature results in significant recovery of Charge Collection Efficiency (CCE). Among other potential benefits of operation at cryogenic temperatures are the use of large low-resistivity wafers, simple processing, higher and faster electrical signal because of higher mobility and drift velocity of carriers, and lower noise of the readout circuit. A substantial reduction in sensor cost could result The first goal of the approved extension of the RD39 program is to demonstrate that irradiation at low temperature in situ during operation does not affect the results obtained so far by cooling detectors which were irradiated at room temperature. In particular we shall concentrate on processes and materials that could significantly reduce th...

Noble gas studies in vapor-growth diamonds: Comparison with shock-produced diamonds and the origin of diamonds in ureilites

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Junichi; Fukunaga, Kazuya; Ito, Keisuke (Kobe Univ. (Japan))

1991-07-01

The authors synthesized vapor-trowth diamonds by two kinds of Chemical Vapor Deposition (CVD) using microwave (MWCVD) and hot filament (HFCVD) ionization of gases, and examined elemental abundances and isotopic compositions of the noble gases trapped in the diamonds. It is remarkable that strong differences existed in the noble gas concentrations in the two kinds of CVD diamonds: large amounts of noble gases were trapped in the MWCVD diamonds, but not in the HFCVD diamonds. The heavy noble gases (Ar to Xe) in the MWCVD diamonds were highly fractionated compared with those in the ambient atmosphere, and are in good agreement with the calculated fractionation patterns for plasma at an electron temperature of 7,000-9,000 K. These results strongly suggest that the trapping mechanism of noble gases in CVD diamonds is ion implantation during diamond growth. The degrees of fractionation of heavy noble gases were also in good agreement with those in ureilites. The vapor-growth hypothesis is discussed in comparison with the impact-shock hypothesis as a better model for the origin of diamonds in ureilites. The diamond (and graphite, amorphous carbon, too) may have been deposited on early condensates such as Re, Ir, W, etc. This model explains the chemical features of vein material in ureilites; the refractory siderophile elements are enriched in carbon and noble gases and low in normal siderophiles. The vapor-growth model is also compatible with the oxygen isotopic data of ureilites which suggests that nebular processes are primarily responsible for the composition of ureilites.

Recent advances with a hybrid micro-pattern gas detector operated in low pressure H2 and He, for AT-TPC applications

Directory of Open Access Journals (Sweden)

Cortesi Marco

2018-01-01

Full Text Available In view of a possible application as a charge-particle track readout for an Active-Target Time Projection Chamber (AT-TPC, the operational properties and performances of a hybrid Micro-Pattern Gaseous Detector (MPGD were investigated in pure low-pressure Hydrogen (H2 and Helium (He. The detector consists of a MICROMEsh GAseous Structure (MICROMEGAS coupled to a two-cascade THick Gaseous Electron Multiplier (THGEM as a pre-amplification stage. This study reports the effective gain dependence of the hybrid-MPGD at relevant pressure (in the range of 200-760 torr for different detector arrangements. The results of this work are relevant in the field of avalanche mechanism in low-pressure, low-mass noble gases, in particularly for applications of MPGD end-cap readout for active-target Time Projection Chambers (TPC in the field of nuclear physics and nuclear astrophysics.

An amplifier for VUV photomultiplier operating in cryogenic environment

International Nuclear Information System (INIS)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S.; Di Giovanni, A.; D'Inzeo, M.; Franchi, G.; Pazos Clemens, L.

2016-01-01

We present the characterisation of an amplifier potentially interesting for noble liquid detectors. The design has been conceived considering the requirements of low power consumption (less than 30 mW), low noise, amplification factor of 10 at 100 MHz and use of commercial components. The amplifier has been integrated onto an electronic board with a voltage divider to operate an Hamamatsu R11410 photomultiplier tube (used in XENON1T, Aprile et al. (2014) [1] dark matter experiment).

An amplifier for VUV photomultiplier operating in cryogenic environment

Energy Technology Data Exchange (ETDEWEB)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Di Giovanni, A., E-mail: adriano.digiovanni@nyu.edu [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); D' Inzeo, M.; Franchi, G. [Age Scientific srl – Capezzano Pianore (Italy); Pazos Clemens, L. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates)

2016-07-11

We present the characterisation of an amplifier potentially interesting for noble liquid detectors. The design has been conceived considering the requirements of low power consumption (less than 30 mW), low noise, amplification factor of 10 at 100 MHz and use of commercial components. The amplifier has been integrated onto an electronic board with a voltage divider to operate an Hamamatsu R11410 photomultiplier tube (used in XENON1T, Aprile et al. (2014) [1] dark matter experiment).

Noble Gases as tracers of fluid migration in the Haynesville shale and overlying strata

Science.gov (United States)

Byrne, D. J.; Barry, P. H.; Lawson, M.; Ballentine, C. J.

2017-12-01

Noble gases are ideal tracers of physical processes and fluid provenance in crustal systems. Due to their inert nature, they are unaffected by chemical alteration, redox, or biological phenomena that fractionate other geochemical tracers. Noble gas analysis has been used to quantify fluid provenance, interactions, and ages in petroleum systems [1,2], but the effects of hydrocarbon migration on noble gas signatures have not been directly observed. The Haynesville Shale (East Texas & Louisiana), is exploited commercially for unconventional shale gas, but also acts as the source-rock for overlying conventional reservoirs. We present noble gas isotope and abundance data in samples collected from 9 natural gas wells sourced from the Haynesville Shale, as well as 21 from reservoirs in the overlying Cotton Valley (n=7), Travis Peak (n=9), and James (n=5) groups. Using a stratigraphic model, we observe systematic changes in the noble gas signatures as the fluids migrate from the Haynesville source rock to the overlying conventional accumulations. Helium isotope ratios (3He/4He) are strongly radiogenic in the Haynesville and stratigraphically older conventional reservoirs, with the younger reservoirs showing evidence of a mantle helium input. Argon isotope ratios (40Ar/36Ar) are strongly correlated with high 3He/4He, suggesting a similar provenance for radiogenic 40Ar and mantle 3He. Concentrations of groundwater-derived 36Ar are consistently higher in the conventional reservoirs than in the Haynesville shale, reflecting the greater interaction with groundwater during migration. However, 20Ne/36Ar ratios are not significantly different, suggesting that solubility-dependent partitioning is not simply dependent on vertical or horizontal migration distance. Krypton and xenon abundances are higher than expected for groundwater in all samples, a phenomenon that has been observed in many other hydrocarbon accumulations [3]. The excess Xe/Kr ratio is highest in the Haynesville

Optical Properties and Immunoassay Applications of Noble Metal Nanoparticles

International Nuclear Information System (INIS)

Zhu, S.; Zhou, W.

2010-01-01

Noble metal, especially gold (Au) and silver (Ag) nanoparticles exhibit unique and tunable optical properties on account of their surface plasmon resonance (SPR). In this paper, we mainly discussed the theory background of the enhanced optical properties of noble metal nanoparticles. Mie theory, transfer matrix method, discrete dipole approximation (DDA) method, and finite-difference time domain (FDTD) method applied brute-force computational methods for different nanoparticles optical properties. Some important nanostructure fabrication technologies such as nanosphere lithography (NSL) and focused ion beam (FIB) are also introduced in this paper. Moreover, these fabricated nanostructures are used in the plasmonic sensing fields. The binding signal between the antibody and antigen, amyloid-derived diffusible ligands (ADDLs)-potential Alzheimer's disease (AD) biomarkers, and staphylococcal enterotoxin B (SEB) in nano-Moore per liter (nM) concentration level are detected by our designed nanobiosensor. They have many potential applications in the biosensor, environment protection, food security, and medicine safety for health, and so forth, fields.

Optical Properties and Immunoassay Applications of Noble Metal Nanoparticles

Directory of Open Access Journals (Sweden)

Shaoli Zhu

2010-01-01

Full Text Available Noble metal, especially gold (Au and silver (Ag nanoparticles exhibit unique and tunable optical properties on account of their surface plasmon resonance (SPR. In this paper, we mainly discussed the theory background of the enhanced optical properties of noble metal nanoparticles. Mie theory, transfer matrix method, discrete dipole approximation (DDA method, and finite-difference time domain (FDTD method applied brute-force computational methods for different nanoparticles optical properties. Some important nanostructure fabrication technologies such as nanosphere lithography (NSL and focused ion beam (FIB are also introduced in this paper. Moreover, these fabricated nanostructures are used in the plasmonic sensing fields. The binding signal between the antibody and antigen, amyloid-derived diffusible ligands (ADDLs-potential Alzheimer's disease (AD biomarkers, and staphylococcal enterotixn B (SEB in nano-Moore per liter (nM concentration level are detected by our designed nanobiosensor. They have many potential applications in the biosensor, environment protection, food security, and medicine safety for health, and so forth, fields.

Flameless atomic absorption determination of noble metals after extraction by mixture of di-2-ethylhexyldithiophosphoric acid and n-octylaniline

International Nuclear Information System (INIS)

Yukhin, Yu.M.; Udalova, T.A.; Tsimbalist, V.G.; AN SSSR, Novosibirsk. Inst. Geologii i Geofiziki)

1985-01-01

A possibility of using the mixture of di-2-ethylhexyl dithiophosphoric acid (D2EHDTPA) and p-octylaniline (OA) (extractants of acid and basic character) for extraction atomic absorption determination of noble metals is studied. The mixture of D2EHDTPA with OA is shown to extract noble metals from hydrochloric acid solutions with distribution factors > 10 3 . An extraction atomic absorption method for determination of noble metals in copperbearing materials is suggested. The minimum determined contents of noble metals at the initial sample equal to 100 for gold, silver, platinum, palladium, rhodium and ruthenium make up (g/t) 0.0005, 0.0001, 0.015, 0.005, 0.002 and 0.015 respectively. Relative standard deviation constitutes Ssub(r)<0.2

Quantification of maltol in Korean ginseng (Panax ginseng) products by high-performance liquid chromatography-diode array detector

Science.gov (United States)

Jeong, Hyun Cheol; Hong, Hee-Do; Kim, Young-Chan; Rhee, Young Kyoung; Choi, Sang Yoon; Kim, Kyung-Tack; Kim, Sung Soo; Lee, Young-Chul; Cho, Chang-Won

2015-01-01

Background: Maltol, as a type of phenolic compounds, is produced by the browning reaction during the high-temperature treatment of ginseng. Thus, maltol can be used as a marker for the quality control of various ginseng products manufactured by high-temperature treatment including red ginseng. For the quantification of maltol in Korean ginseng products, an effective high-performance liquid chromatography-diode array detector (HPLC-DAD) method was developed. Materials and Methods: The HPLC-DAD method for maltol quantification coupled with a liquid-liquid extraction (LLE) method was developed and validated in terms of linearity, precision, and accuracy. An HPLC separation was performed on a C18 column. Results: The LLE methods and HPLC running conditions for maltol quantification were optimized. The calibration curve of the maltol exhibited good linearity (R2 = 1.00). The limit of detection value of maltol was 0.26 μg/mL, and the limit of quantification value was 0.79 μg/mL. The relative standard deviations (RSDs) of the data of the intra- and inter-day experiments were <1.27% and 0.61%, respectively. The results of the recovery test were 101.35–101.75% with an RSD value of 0.21–1.65%. The developed method was applied successfully to quantify the maltol in three ginseng products manufactured by different methods. Conclusion: The results of validation demonstrated that the proposed HPLC-DAD method was useful for the quantification of maltol in various ginseng products. PMID:26246746

A high-resolution detector based on liquid-core scintillating fibres with readout via an electron-bombarded charge-coupled device

International Nuclear Information System (INIS)

Cianfarani, C.; Duane, A.; Fabre, J.P.; Frenkel, A.; Golovkin, S.V.; Gorin, A.M.; Harrison, K.; Kozarenko, E.N.; Kushnirenko, A.E.; Ladygin, E.A.; Martellotti, G.; Medvedkov, A.M.; Nass, P.A.; Obudovski, V.P.; Penso, G.; Petukhov, Yu.P.; Siegmund, W.P.; Tyukov, V.E.; Vasilchenko, V.G.

1994-01-01

This paper is a presentation of results from tests in a 5 GeV/c hadron beam of detectors based on liquid-core scintillating fibres, each fibre consisting of a glass capillary filled with organic liquid scintillator. Fibre readout was performed via an Electron-Bombarded Charge-Coupled Device (EBCCD) image tube, a novel instrument that combines the functions of a high-gain, gated image intensifier and a Charge-Coupled Device. Using 1-methylnaphthalene doped with 3 g/l of R45 as liquid scintillator, the attenuation lengths obtained for light propagation over distances greater than 16 cm were 1.5 m in fibres of 20 μm core and 1.0 m in fibres of 16 μm core. For particles that crossed the fibres of 20 μm core at distances of ∼1.8 cm and ∼95 cm from the fibres' readout ends, the recorded hit densities were 5.3 mm -1 and 2.5 mm -1 respectively. Using 1-methylnaphthalene doped with 3.6 g/l of R39 as liquid scintillator and fibres of 75 μm core, the hit density obtained for particles that crossed the fibres at a distance of ∼1.8 cm from their readout ends was 8.5 mm -1 . With a specially designed bundle of tapered fibres, having core diameters that smoothly increase from 16 μm to 75 μm, a spatial precision of 6 μm was measured. (orig.)

The role of noble metals in electric melting of nuclear waste glass

International Nuclear Information System (INIS)

Roth, G.; Weisenburger, S.

1990-01-01

Electrical melting of nuclear waste glass in ceramic melters applies Joule heating, with the molten glass acting as the conductive medium. The local energy release inside the melt relieves from the restriction of external heat addition, allowing to scale up the melter to industrial units. Certainly, that principle makes the melter operation susceptible for changes of the electrical properties of the glass melt. Hence, the melt properties are required to be locally uniform and constant with time. Temporary fluctuations in the feed composition, however, are usually attenuated by the high retention times being in the order of a day and more. More essential for the melter operation are segregation effects occurring systematically. This behaviour can be observed in the case of the so-called noble metal elements Ruthenium, Palladium and Rhodium, belonging to the Platinum metal group. The subject of this paper is to describe the behaviour of the noble metals in electric melting and the problems they can contribute to. The discussion is based on detailed knowledge gained from PAMELA's LEWC processing and from large-scale vitrification of commercial-like waste simulate at INE/KfK. Finally, ways are indicated to solve the noble metal problem technically

Electron--noble-gas spin-flip scattering at low energy

International Nuclear Information System (INIS)

Walker, T.G.; Bonin, K.; Happer, W.

1987-01-01

The spin-exchange rates and spin-relaxation rates for thermal electrons colliding with noble-gas atoms are calculated using the orthogonalized-plane-wave approximation and via partial-wave analysis. The two techniques give similar results and are in order-of-magnitude agreement with the experimental rate in Ar

Noble gas atmospheric monitoring for international safeguards at reprocessing plants

International Nuclear Information System (INIS)

Nakhleh, C.W.; Poths, J.; Stanbro, W.D.; Perry, R.T. Jr.; Wilson, W.B.; Fearey, B.L.

1997-01-01

The use of environmental sampling is a major component of the improvements of International Atomic Energy Agency safeguards being carried out under Program 93+2. Nonradioactive noble gas isotopic measurements in the effluent stream of large reprocessing facilities may provide useful confirmatory information on the burnup and reactor type of the spent fuel undergoing reprocessing. The authors have taken and analyzed stack samples at an operating facility. The data show clear fission signals. The authors are currently applying a maximum-likelihood estimation procedure to determine the fuel burnup from these data. They anticipate that the general features involved in the table noble gas problem--selection of appropriate signals, measurement of those signals under realistic conditions, and inverse calculation of parameters of interest from the environmental data--will be present in all environmental sampling problems. These methods should therefore be widely applicable

Modeling impurity-assisted chain creation in noble-metal break junctions

International Nuclear Information System (INIS)

Di Napoli, S; Thiess, A; Blügel, S; Mokrousov, Y

2012-01-01

In this work we present the generalization of the model for chain formation in break junctions, introduced by Thiess et al (2008 Nano Lett. 8 2144), to zigzag transition-metal chains with s and p impurities. We apply this extended model to study the producibility trends for noble-metal chains with impurities, often present in break junction experiments, namely, Cu, Ag and Au chains with H, C, O and N adatoms. Providing the material-specific parameters for our model from systematic full-potential linearized augmented plane-wave first-principles calculations, we find that the presence of such impurities crucially affects the binding properties of the noble-metal chains. We reveal that both the impurity-induced bond strengthening and the formation of zigzag bonds can lead to a significantly enhanced probability for chain formation in break junctions. (paper)

Characterisation and radiolysis of modified lithium orthosilicate pebbles with noble metal impurities

DEFF Research Database (Denmark)

Tamulevičius, Sigitas; Zariņš, A.; Valtenbergs, O.

2017-01-01

Modified lithium orthosilicate (Li4SiO4) pebbles with additions of titanium dioxide (TiO2) are suggested as an alternative tritium breeding ceramic for the European solid breeder test blanket module. The noble metals – platinum (Pt), gold (Au) and rhodium (Rh), can be introduced into the modified...... Li4SiO4 pebbles during the melt-based process, due to the corrosion of Pt-Rh and Pt-Au alloy crucible components. In this study, the surface microstructure, chemical and phase composition of the modified Li4SiO4 pebbles with different contents of the noble metals was analysed. The influence...

Light-controlled relaxation of the rat penile corpus cavernosum using NOBL-1, a novel nitric oxide releaser

Directory of Open Access Journals (Sweden)

Yuji Hotta

2016-05-01

Full Text Available Purpose: To investigate whether relaxation of the rat penile corpus cavernosum could be controlled with NOBL-1, a novel, lightcontrollable nitric oxide (NO releaser. Materials and Methods: Fifteen-week-old male Wistar-ST rats were used. The penile corpus cavernosum was prepared and used in an isometric tension study. After noradrenaline (10−5 M achieved precontraction, the penile corpus cavernosum was irradiated by light (470–500 nm with and without NOBL-1 (10−6 M. In addition, we noted rats’ responses to light with vardenafil (10−6 M, a phosphodiesterase-5 (PDE-5 inhibitor. Next, responses to light in the presence of a guanylate cyclase inhibitor, ODQ (1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (10−5 M, were measured. All measurements were performed in pretreated L-NAME (10−4 M conditions to inhibit endogenous NO production. Results: Corpus cavernosal smooth muscle, precontracted with noradrenaline, was unchanged by light irradiation in the absence of NOBL-1. However, in the presence of NOBL-1, corpus cavernosal smooth muscle, precontracted with noradrenaline, relaxed in response to light irradiation. After blue light irradiation ceased, tension returned. In addition, the light response was obviously enhanced in the presence of a PDE-5 inhibitor. Conclusions: This study showed that rat corpus cavernosal smooth muscle relaxation can be light-controlled using NOBL-1, a novel, light sensitive NO releaser. Though further in vivo studies are needed to investigate possible usefulness, NOBL-1 may be prove to be a useful tool for erectile dysfunction therapy, specifically in the field of penile rehabilitation.

Radon daughter plate-out onto Teflon

Science.gov (United States)

Morrison, E. S.; Frels, T.; Miller, E. H.; Schnee, R. W.; Street, J.

2018-01-01

Radiopure materials for detector components in rare event searches may be contaminated after manufacturing with long-lived 210Pb produced by the decay of atmospheric radon. Charged radon daughters deposited on the surface or implanted in the bulk of detector materials have the potential to cause noticeable backgrounds within dark matter regions of interest. Understanding the mechanics governing these background signals is therefore a paramount concern in dark matter experiments in order to distinguish a real signal from internal detector backgrounds. Teflon (i.e. PTFE) is a specific material of interest because it makes up the walls of the inner detector of many liquid noble detectors such as the LUX-ZEPLIN experiment. The rate of radon daughter plate-out onto Teflon can be orders of magnitude larger than the plate-out rate onto other materials. Mitigation of plate-out onto Teflon and steel by proximity to other materials is demonstrated.

Non-noble metal fuel cell catalysts

CERN Document Server

Chen, Zhongwei; Zhang, Jiujun

2014-01-01

Written and edited by a group of top scientists and engineers in the field of fuel cell catalysts from both industry and academia, this book provides a complete overview of this hot topic. It covers the synthesis, characterization, activity validation and modeling of different non-noble metal and metalfree electrocatalysts for the reduction of oxygen, as well as their integration into acid or alkaline polymer exchange membrane (PEM) fuel cells and their performance validation, while also discussing those factors that will drive fuel cell commercialization. With its well-structured app

Noble gases and the early history of the Earth: Inappropriate paradigms and assumptions inhibit research and communication

Science.gov (United States)

Huss, G. R.; Alexander, E. C., Jr.

1985-01-01

The development of models as tracers of nobel gases through the Earth's evolution is discussed. A new set of paradigms embodying present knowledge was developed. Several important areas for future research are: (1) measurement of the elemental and isotopic compositions of the five noble gases in a large number of terrestrial materials, thus better defining the composition and distribution of terrestrial noble gases; (2) determinations of relative diffusive behavior, chemical behavior, and the distribution between solid and melt of noble gases under mantle conditions are urgently needed; (3) disequilibrium behavior in the nebula needs investigation, and the behavior of plasmas and possible cryotrapping on cold nebular solids are considered.

Electron shell contributions to gamma-ray spectra of positron annihilation in noble gases

Energy Technology Data Exchange (ETDEWEB)

Wang, Feng; Selvam, Lalitha [Centre for Molecular Simulation, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122 (Australia); Gribakin, Gleb F [Department of Applied Mathematics and Theoretical Physics, Queen' s University Belfast BT7 1NN (United Kingdom); Surko, Clifford M, E-mail: fwang@swin.edu.a [Physics Department, University of California, San Diego, La Jolla, CA 92093-0319 (United States)

2010-08-28

Gamma-ray positron annihilation spectra of the noble gases are simulated using computational chemistry tools for the bound electron wavefunctions and plane-wave approximation for the low-energy positron. The present annihilation line shapes, i.e. the full width at half maximum, {Delta}{epsilon}, of the {gamma}-ray annihilation spectra for He and Ar (valence) agree well with available independent atomic calculations using a different algorithm. For other noble gases they achieve moderate agreement with the experimental measurements. It is found that the contributions of various atomic electron shells to the spectra depend significantly on their principal quantum number n and orbital angular momentum quantum number l. The present study further reveals that the outermost ns electrons of the noble gases exhibit spectral line shapes in close agreement with those measured, indicating (as expected) that the measurements are not due to a simple sum over the momentum densities for all atomic electrons. The robust nature of the present approach makes it possible for us to proceed to more complex molecular systems using the tools of modern computational chemistry.

Gamma radiation detectors for safeguards applications

International Nuclear Information System (INIS)

Carchon, R.; Moeslinger, M.; Bourva, L.; Bass, C.; Zendel, M.

2007-01-01

The IAEA uses extensively a variety of gamma radiation detectors to verify nuclear material. These detectors are part of standardized spectrometry systems: germanium detectors for High-Resolution Gamma Spectrometry (HRGS); Cadmium Zinc Telluride (CZT) detectors for Room Temperature Gamma Spectrometry (RTGS); and NaI(Tl) detectors for Low Resolution Gamma Spectrometry (LRGS). HRGS with high-purity Germanium (HpGe) detectors cooled by liquid nitrogen is widely used in nuclear safeguards to verify the isotopic composition of plutonium or uranium in non-irradiated material. Alternative cooling systems have been evaluated and electrically cooled HpGe detectors show a potential added value, especially for unattended measurements. The spectrometric performance of CZT detectors, their robustness and simplicity are key to the successful verification of irradiated materials. Further development, such as limiting the charge trapping effects in CZT to provide improved sensitivity and energy resolution are discussed. NaI(Tl) detectors have many applications-specifically in hand-held radioisotope identification devices (RID) which are used to detect the presence of radioactive material where a lower resolution is sufficient, as they benefit from a generally higher sensitivity. The Agency is also continuously involved in the review and evaluation of new and emerging technologies in the field of radiation detection such as: Peltier-cooled CdTe detectors; semiconductor detectors operating at room temperature such as HgI 2 and GaAs; and, scintillator detectors using glass fibres or LaBr 3 . A final conclusion, proposing recommendations for future action, is made

Percutaneous coronary intervention versus coronary artery bypass grafting: where are we after NOBLE and EXCEL?

Science.gov (United States)

Fortier, Jacqueline H; Shaw, Richard E; Glineur, David; Grau, Juan B

2017-11-01

The publication of the NOBLE and EXCEL trials, with seemingly conflicting results, brought into question whether percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) is better for low-risk patients with left main coronary artery stenosis (LMCAS). This review appraises the methods and results of NOBLE and EXCEL, contextualizes them within the literature, and determines how they may affect clinical practice. We appraised the trials and describe differences in methodology and results. NOBLE recruited primarily isolated LMCAS, and found that CABG was superior to PCI. EXCEL's population included patients LMCAS in the context of multivessel CAD, and found PCI and CABG were comparable. Both trials enrolled young patients with few comorbidities, and there was more protocol-mandated consistency in the procedural techniques and medical therapy of patients receiving PCI. The generalizability of these trials is limited by the use of young, healthy patients at highly skilled centres that rarely reflect typical clinical practice. If these studies are to maintain relevance, trialists must address the lack of protocolization of surgical interventions and inconsistent medical therapies. Unfortunately, the limitations of NOBLE and EXCEL mean that we are no closer to answering the question of what is the optimal treatment for patients with LMCAS.

Determining random counts in liquid scintillation counting

International Nuclear Information System (INIS)

Horrocks, D.L.

1979-01-01

During measurements involving coincidence counting techniques, errors can arise due to the detection of chance or random coincidences in the multiple detectors used. A method and the electronic circuits necessary are here described for eliminating this source of error in liquid scintillation detectors used in coincidence counting. (UK)

(Liquid + liquid) equilibria of (water + linalool + limonene) ternary system at T = (298.15, 308.15, and 318.15) K

International Nuclear Information System (INIS)

Gramajo de Doz, Monica B.; Cases, Alicia M.; Solimo, Horacio N.

2008-01-01

(Liquid + liquid) equilibrium (LLE) data for {water (1) + linalool (2) + limonene (3)} ternary system at T = (298.15, 308.15, and 318.15 ± 0.05) K are reported. The organic chemicals were quantified by gas chromatography using a flame ionisation detector while water was quantified using a thermal conductivity detector. The effect of the temperature on (liquid + liquid) equilibrium is determined and discussed. Experimental data for the ternary mixture are compared with values calculated by the NRTL and UNIQUAC equations, and predicted by means of the UNIFAC group contribution method. It is found that the UNIQUAC and NRTL models provide a good correlation of the solubility curve at these three temperatures, while comparing the calculated values with the experimental ones, the best fit is obtained with the NRTL model. Finally, the UNIFAC model provides poor results, since it predicts a greater heterogeneous region than experimentally observed

Liquid Level Sensing System

Science.gov (United States)

Korman, Valentin (Inventor); Wiley, John T. (Inventor); Duffell, Amanda G. (Inventor)

2014-01-01

A liquid level sensing system includes waveguides disposed in a liquid and distributed along a path with a gap between adjacent waveguides. A source introduces electromagnetic energy into the waveguides at a first end of the path. A portion of the electromagnetic energy exits the waveguides at a second end of the path. A detector measures the portion of the electromagnetic energy exiting the second end of the path.

Noble gas confinement for reactor fuel melting accidents

International Nuclear Information System (INIS)

Monson, P.R.

1984-01-01

In the unlikely event of a fuel melting accident, radioactive material would be released into the reactor room. This radioactive material would consist of particulate matter, iodine, tritium, and the noble gases krypton and xenon. In the case of reactors with containment domes the gases would be contained for subsequent cleanup. For reactors without contaiment the particulates and the iodine can be effectively removed with HEPA and carbon filters of current technology; however, noble gases cannot be easily removed and would be released to the atmosphere. In either case, it would be highly desirable to have a system that could be brought online to treat this contaminated air to minimize the population dose. A low temperature adsorption system has been developed at the Savannah River Laboratory to remove the airborne radioactive material from such a fuel melting accident. Over two dozen materials have been tested in extensive laboratory studies, and hydrogen mordenite and silver mordenite were found to be the most promising adsorbents. A full-scale conceptual design has also been developed. Results of the laboratory studies and the conceptual design are discussed along with plans for further development of this concept

Noble gas confinement for reactor fuel melting accidents

International Nuclear Information System (INIS)

Monson, P.R.

1985-01-01

In the unlikely event of a fuel melting accident radioactive material would be released into the reactor room. This radioactive material would consist of particulate matter, iodine, tritium, and the noble gases krypton and xenon. In the case of reactors with containment domes, the gases would be contained for subsequent cleanup. For reactors without containment the particulates and the iodine can be effectively removed with HEPA and carbon filters of current technology; however, noble gases cannot be easily removed and would be released to the atmosphere. In either case, it would be highly desirable to have a system that could be brought online to treat this contaminated air to minimize the population dose. A low temperature adsorption system has been developed at the Savannah River Laboratory to remove the airborne radioactive material from such a fuel melting accident. Over two dozen materials have been tested in extensive laboratory studies, and hydrogen mordensite and silver mordenite were found to be the most promising absorbents. A full-scale conceptual design has also been developed. Results of the laboratory studies and the conceptual design will be discussed along with plans for further development of this concept

Isotopic and noble gas geochemistry in geothermal research

Energy Technology Data Exchange (ETDEWEB)

Kennedy, B.M.; DePaolo, D.J. [Lawrence Berkeley National Lab., CA (United States)

1997-12-31

The objective of this program is to provide, through isotopic analyses of fluids, fluid inclusions, and rocks and minerals coupled with improved methods for geochemical data analysis, needed information regarding sources of geothermal heat and fluids, the spatial distribution of fluid types, subsurface flow, water-rock reaction paths and rates, and the temporal evolution of geothermal systems. Isotopic studies of geothermal fluids have previously been limited to the light stable isotopes of H, C, and O. However, other isotopic systems such as the noble gases (He, Ne, Ar, Kr and Xe) and reactive elements (e.g. B, N, S, Sr and Pb) are complementary and may even be more important in some geothermal systems. The chemistry and isotopic composition of a fluid moving through the crust will change in space and time in response to varying chemical and physical parameters or by mixing with additional fluids. The chemically inert noble gases often see through these variations, making them excellent tracers for heat and fluid sources. Whereas, the isotopic compositions of reactive elements are useful tools in characterizing water-rock interaction and modeling the movement of fluids through a geothermal reservoir.

Liquid-liquid extraction in flow analysis: A critical review

Energy Technology Data Exchange (ETDEWEB)

Silvestre, Cristina I.C.; Santos, Joao L.M. [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Lima, Jose L.F.C., E-mail: limajlfc@ff.up.pt [REQUIMTE, Servico de Quimica-Fisica, Faculdade de Farmacia, Universidade do Porto, R. Anibal Cunha, 164, 4099-030 Porto (Portugal); Zagatto, Elias A.G. [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, P.O. Box 96, Piracicaba 13400-970 (Brazil)

2009-10-12

Liquid-liquid extractions (LLE) are a common sample pre-treatment in many analytical applications. This review aims at providing a critical overview of the distinct automated continuous flow-based approaches that were developed for liquid-liquid extraction with the purpose of pre-concentration and/or separation of multiple analytes, such as ultra-trace metal and metalloid species, phenolic compounds, surfactants, pharmaceuticals, etc., hyphenated with many detection technique such as UV/vis spectrophotometry, atomic spectrometric detection systems and luminescent detectors, including distinct extraction strategies and applications like single and multiple extraction schemes, wetting film extraction, supported liquid membrane extraction, back extraction, closed-loop systems and the utilisation of zone sampling, chromatomembranes and iterative reversal techniques. The analytical performance of the developed flow-based LLE methods and the influence of flow manifold components such as the segmenter, extraction coil and phase separator, is emphasised and object of discussion. An overall presentation of each system components, selectivity, advantages and shortcomings is carried out and exemplified with selected applications.

An experimental investigation of a liquid cooling scheme for the low dropout voltage regulators of the multiplicity and vertex detector

International Nuclear Information System (INIS)

Bernardin, J.D.; Bosze, E.

1997-10-01

This report presents a summary of an experimental investigation of a liquid cooling system for the low dropout voltage regulators in the multiplicity and vertex detector (MVD), a device used to determine and characterize the collision location of two accelerated heavy ions. The coolant temperatures and flow rates as well as the voltage regulator operating temperatures were used to assess and optimize the performance of the proposed cooling system, identify potential assembly problems and system limitations, and provide the necessary information for designing and sizing the final MVD cooling system components. The MVD is part of the PHENIX experiment at Brookhaven RHIC

Cashew nut shell liquid resin used as matrix for compound materials

International Nuclear Information System (INIS)

Abreu, Hamilton Ferreira Gomes de; Nogueira, Ricardo Emilio Ferreira Quevedo

1996-01-01

Cashew nut shell liquid resin a by product of cashew processing industry is a naturally occurring phenol of low cost and are used in Brazil as fuel in the industrial production of cashew nut or as a structural material when associated with coconut fiber or rice shell. A high measured Tg points to noble applications. This paper presents some properties of LCC resin and concludes that it has good perspectives as a composite matrice to work at elevated temperatures. (author)

Noble gases in ten stone meteorites from Antarctica

International Nuclear Information System (INIS)

Weber, H.W.; Schultz, L.

1980-01-01

The concentrations and isotopic composition of noble gases have been determined in all ten stone meteorites recovered in Antarctica during 1976-1977 by a U.S.-Japanese expedition. From a comparison of spallogenic and radiogenic gas components it is concluded that the chondrites Mt. Baldr (a) and Mt. Baldr (b) belong to the same fall but that all other stone meteorites are individual finds. (orig.)

Tritium labeling of amino acids and peptides with liquid and solid tritium

International Nuclear Information System (INIS)

Peng, C.T.; Hua, R.L.; Souers, P.C.; Coronado, P.R.

1988-01-01

Amino acids and peptides were labeled with liquid and solid tritium at 21 K and 9 K. At these low temperatures radiation degradation is minimal, and tritium incorporation increases with tritium concentration and exposure time. Ring saturation in L-phenyl-alanine does not occur. Peptide linkage in oligopeptides is stable toward tritium. Deiodination in 3-iodotyrosine and 3,5-diiodotyrosine occurs readily and proceeds in steps by losing one iodine atom at a time. Nickel and noble metal supported catalysts when used as supports for dispersion of the substrate promote tritium labeling at 21 K. Our study shows that both liquid and solid tritium are potentially useful agents for labeling peptides and proteins. 11 refs., 1 fig., 3 tabs

Tritium labeling of amino acids and peptides with liquid and solid tritium

International Nuclear Information System (INIS)

Souers, P.C.; Coronado, P.R.; Peng, C.T.; Hua, R.L.

1988-01-01

Amino acids and peptides were labeled with liquid and solid tritium at 21/degree/K and 9/degree/K. At these low temperatures radiation degradation is minimal, and tritium incorporation increases with tritium concentration and exposure time. Ring saturation in L-phenylalanine does not occur. Peptide linkage in oligopeptides is stable toward tritium. Deiodination in 3-iodotyrosine and 3,5-diiodotyrosine occurs readily and proceeds in steps by losing one iodine atom at a time. Nickel and noble metal supported catalysts when used as supports for dispersion of the substrate promote tritium labeling at 21 K. Our study shows that both liquid and solid tritiums are potentially useful agents for labeling peptides and proteins

Attosecond Time Delay in Photoionization of Noble-Gas and Halogen Atoms

Directory of Open Access Journals (Sweden)

Liang-Wen Pi

2018-02-01

Full Text Available Ultrafast processes are now accessible on the attosecond time scale due to the availability of ultrashort XUV laser pulses. Noble-gas and halogen atoms remain important targets due to their giant dipole resonance and Cooper minimum. Here, we calculate photoionization cross section, asymmetry parameter and Wigner time delay using the time-dependent local-density approximation (TDLDA, which includes the electron correlation effects. Our results are consistent with experimental data and other theoretical calculations. The asymmetry parameter provides an extra layer of access to the phase information of the photoionization processes. We find that halogen atoms bear a strong resemblance on cross section, asymmetry parameter and time delay to their noble-gas neighbors. Our predicted time delay should provide a guidance for future experiments on those atoms and related molecules.

OPTICALLY BASED CHARGE INJECTION SYSTEM FOR IONIZATION DETECTORS

International Nuclear Information System (INIS)

CHEN, H.; CITTERIO, M.; LANNI, F.; LEITE, M.A.L.; RADEKA, V.; RESCIA, S.; TAKAI, H.

2001-01-01

An optically coupled charge injection system for ionization based radiation detectors which allows a test charge to be injected without the creation of ground loops has been developed. An ionization like signal from an external source is brought into the detector through an optical fiber and injected into the electrodes by means of a photodiode. As an application example, crosstalk measurements on a liquid Argon electromagnetic calorimeter readout electrodes were performed

Volatile elements - water, carbon, nitrogen, noble gases - on Earth

Science.gov (United States)

Marty, B.

2017-12-01

Understanding the origin and evolution of life-bearing volatile elements (water, carbon, nitrogen) on Earth is a fruitful and debated area of research. In his pioneering work, W.W. Rubey inferred that the terrestrial atmosphere and the oceans formed from degassing of the mantle through geological periods of time. Early works on noble gas isotopes were consistent with this view and proposed a catastrophic event of mantle degassing early in Earth's history. We now have evidence, mainly from noble gas isotopes, that several cosmochemical sources contributed water and other volatiles at different stages of Earth's accretion. Potential contributors include the protosolar nebula gas that equilibrated with magma oceans, inner solar system bodies now represented by chondrites, and comets. Stable isotope ratios suggest volatiles where primarily sourced by planetary bodies from the inner solar system. However, recent measurements by the European Space Agency Rosetta probe on the coma of Comet 67P/Churyumov-Gerasimenko permit to set quantitative constraints on the cometary contribution to the surface of our planet. The surface and mantle reservoirs volatile elements exchanged volatile elements through time, with rates that are still uncertain. Some mantle regions remained isolated from whole mantle convection within the first tens to hundreds million years after start of solar system formation. These regions, now sampled by some mantle plumes (e.g., Iceland, Eifel) preserved their volatile load, as indicated by extinct and extant radioactivity systems. The abundance of volatile elements in the mantle is still not well known. Different approaches, such as high pressure experimental petrology, noble gas geochemistry, modelling, resulted in somewhat contrasted estimates, varying over one order of magnitude for water. Comparative planetology, that is, the study of volatiles on the Moon, Venus, Mars, Vesta, will shed light on the sources and strengths of these elements in the

A review of noble gas geochemistry in relation to early Earth history

Science.gov (United States)

Kurz, M. D.

1985-01-01

One of the most fundamental noble gas constraints on early Earth history is derived from isotopic differences in (129)Xe/(130)Xe between various terrestrial materials. The short half life (17 m.y.) of extinct (129I, parent of (129)Xe, means that these differences must have been produced within the first 100 m.y. after terrestrial accretion. The identification of large anomalies in (129)Xe/(130)Xe in mid ocean ridge basalts (MORB), with respect to atmospheric xenon, suggests that the atmosphere and upper mantle have remained separate since that time. This alone is a very strong argument for early catastrophic degassing, which would be consistent with an early fractionation resulting in core formation. However, noble gas isotopic systematics of oceanic basalts show that the mantle cannot necessarily be regarded as a homogeneous system, since there are significant variations in (3)He/(4)He, (40)Ar/(36)Ar, and (129)Xe/(130)Xe. Therefore, the early degassing cannot be considered to have acted on the whole mantle. The specific mechanisms of degassing, in particular the thickness and growth of the early crust, is an important variable in understanding present day noble gas inventories. Another constraint can be obtained from rocks that are thought to be derived from near the lithosphere asthenosphere boundary: ultramafic xenoliths.

High efficiency scintillation detectors

International Nuclear Information System (INIS)

Noakes, J.E.

1976-01-01

A scintillation counter consisting of a scintillation detector, usually a crystal scintillator optically coupled to a photomultiplier tube which converts photons to electrical pulses is described. The photomultiplier pulses are measured to provide information on impinging radiation. In inorganic crystal scintillation detectors to achieve maximum density, optical transparency and uniform activation, it has been necessary heretofore to prepare the scintillator as a single crystal. Crystal pieces fail to give a single composite response. Means are provided herein for obtaining such a response with crystal pieces, such means comprising the combination of crystal pieces and liquid or solid organic scintillator matrices having a cyclic molecular structure favorable to fluorescence. 8 claims, 6 drawing figures

Evaluating analytical ionization quenching correction models for 3D liquid organic scintillator detector

Science.gov (United States)

Alsanea, F.; Beddar, S.

2017-05-01

Proton therapy offers dosimetric advantage over conventional photon therapy due to the finite range of the proton beam, which improves dose conformity. However, one of the main challenges of proton beam therapy is verification of the complex treatment plans delivered to a patient. Thus, 3D measurements are needed to verify the complex dose distribution. A 3D organic scintillator detector is capable of such measurements. However, organic scintillators exhibit a non-linear relation to the ionization density called ionization quenching. The ionization quenching phenomenon in organic scintillators must be accounted for to obtain accurate dose measurements. We investigated the energy deposition by secondary electrons (EDSE) model to explain ionization quenching in 3D liquid organic scintillator when exposed to proton beams. The EDSE model was applied to volumetric scintillation measurement of proton pencil beam with energies of 85.6, 100.9, 144.9 and 161.9 MeV. The quenching parameter in EDSE model ρq was determined by plotting the total light output vs the initial energy of the ion. The results were compared to the Birks semi-empirical formula of scintillation light emission.

Modification of titanium electrodes by a noble metal deposit

Energy Technology Data Exchange (ETDEWEB)

Devilliers, D.; Mahe, E. [Pierre et Marie Curie Univ., Paris (France). Laboratoire LI2C, UMR CNRS

2008-07-01

Titanium is commonly used as a substrate for dimensionally stable anodes (DSAs) because it is corrosion-resistant in acid media and because a passive titanium oxide (TiO2) film can be formed on the surface. This paper reported on a study in which titanium substrates were first covered by anodization with a TiO2 layer. The electrochemical properties of the Ti/TiO2 electrodes were investigated. The modification of the substrates by cathodic electrodeposition of a noble metal was described. The reactivity of the Ti/TiO2/Pt structures were illustrated by impedance spectroscopy experiments. The impedance studies performed with Ti/ TiO2 electrodes in the presence of a redox couple in solution (Fe3+/Fe2+ system in sulphuric acid) showed that the electronic transfer is very slow. It was concluded that the deposition of a noble metal coating on Ti/TiO2 substrates leads to modified titanium electrodes that exhibit electrocatalytic behaviour versus specific electrochemical reactions. 1 ref., 3 figs.

A new water-based liquid scintillator and potential applications

Energy Technology Data Exchange (ETDEWEB)

Yeh, M., E-mail: yeh@bnl.gov [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Hans, S.; Beriguete, W.; Rosero, R.; Hu, L.; Hahn, R.L. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Diwan, M.V.; Jaffe, D.E.; Kettell, S.H.; Littenberg, L. [Physics Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2011-12-21

In this paper we describe a new type of scintillating liquid based on water. We describe the concept, preparation, and properties of this liquid, and how it could be used for a very large, but economical detector. The applications of such a detector range from fundamental physics such as nucleon decay and neutrino physics to physics with broader application such as neutron detection. We briefly describe the scientific requirements of these applications, and how they can be satisfied by the new material.

Beta-induced fluorescence detection in liquid chromatography

International Nuclear Information System (INIS)

Malcolme-Lawes, D.J.; Massey, S.; Warwick, P.

1981-01-01

A theoretical analysis of beta-induced fluorescence is used to determine the factors which influence the sensitivity of the technique as applied to liquid chromatography. Equations are presented for detector response and for signal-to-noise ratios and the theoretical response for a typical detector is compared with experimentally determined values. (author)

Study of the material photon and electron background and the liquid argon detector veto efficiency of the CDEX-10 experiment

International Nuclear Information System (INIS)

Su Jian; Zeng Zhi; Ma Hao

2015-01-01

The China Dark Matter Experiment (CDEX) is located at the China Jinping Underground Laboratory (CJPL) and aims to directly detect the weakly interacting massive particles (WIMP) flux with high sensitivity in the low mass region. Here we present a study of the predicted photon and electron backgrounds including the background contribution of the structure materials of the germanium detector, the passive shielding materials, and the intrinsic radioactivity of the liquid argon that serves as an anti-Compton active shielding detector. A detailed geometry is modeled and the background contribution has been simulated based on the measured radioactivities of all possible components within the GEANT4 program. Then the photon and electron background level in the energy region of interest (< 10 -2 events·kg 1 ·day -1 ·keV -1 (cpkkd)) is predicted based on Monte Carlo simulations. The simulated result is consistent with the design goal of the CDEX-10 experiment, 0.1cpkkd, which shows that the active and passive shield design of CDEX-10 is effective and feasible. (authors)

Precolumn derivatization followed by liquid chromatographic separation and determination of tramiprosate in rat plasma by fluorescence detector: application to pharmacokinetics.

Science.gov (United States)

Rao, R Nageswara; Maurya, Pawan K; Shinde, Dhananjay D; Khalid, Sara

2011-05-15

Alzheimer disease (AD) is characterized pathologically by extracellular amyloid deposits composed of amyloid β (Aβ) protein. A simple and rapid method using HPLC with fluorescence detector was developed and validated for determination of tramiprosate in rat plasma. Pre-column derivatization of the deproteinized rat plasma was carried out using o-phthaldialdehyde (OPA) as a fluorescent reagent in presence of 3-mercaptopropionic acid. The liquid chromatographic separation was achieved on a Kromasil C18 column using methanol:acetonitrile: 20 mM phosphate buffer pH 7.5 (8.0:17.5:74.5 v/v/v) as a mobile phase in an isocratic elution mode. The eluents were monitored by a fluorescence detector set at 330 and 450 nm of excitation and emission wavelength respectively. Vigabatrin was used as an internal standard. The method was linear within the range 30.0-1000.0 ng/mL. Design of experiments (DOE) was used to evaluate the robustness of the method. The developed method was applied to study the pharmacokinetics of tramiprosate in rats. Copyright © 2011. Published by Elsevier B.V.

Novel discrimination parameters for neutron-gamma discrimination with liquid scintillation detectors using wavelet transform

International Nuclear Information System (INIS)

Singh, H.; Singh, S.

2015-01-01

It has been observed that the discrimination performance of the wavelet transform method strongly depends on definition of discrimination parameters. These parameters are usually obtained from a combination of scaling functions at different scales, which represents the energy density of the wavelet coefficients. In this paper, the discrete wavelet transform (DWT) at minimum possible values of scale was investigated. Novel pulse shape discrimination parameters have been proposed for neutron and gamma discrimination in a mixed radiation field and tested with modeled pulses. The performance of these parameters was also validated in terms of quality of discrimination using experimental data of mixed events from an AmBe source collected with BC501 liquid scintillation detector. The quality of discrimination was evaluated by calculating a figure of merit (FOM) with all parameters under same experimental and simulation conditions. The FOM obtained with the proposed novel parameters was also compared with the charge comparison method. The proposed parameters exhibit better FOM as compared to the charge comparison method when high levels of noise are present in the data

High performance liquid chromatography in pharmaceutical analyses

Directory of Open Access Journals (Sweden)

Branko Nikolin

2004-05-01

Full Text Available In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatographyreplaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography(HPLC analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1 Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or

High perfomance liquid chromatography in pharmaceutical analyses.

Science.gov (United States)

Nikolin, Branko; Imamović, Belma; Medanhodzić-Vuk, Saira; Sober, Miroslav

2004-05-01

In testing the pre-sale procedure the marketing of drugs and their control in the last ten years, high performance liquid chromatography replaced numerous spectroscopic methods and gas chromatography in the quantitative and qualitative analysis. In the first period of HPLC application it was thought that it would become a complementary method of gas chromatography, however, today it has nearly completely replaced gas chromatography in pharmaceutical analysis. The application of the liquid mobile phase with the possibility of transformation of mobilized polarity during chromatography and all other modifications of mobile phase depending upon the characteristics of substance which are being tested, is a great advantage in the process of separation in comparison to other methods. The greater choice of stationary phase is the next factor which enables realization of good separation. The separation line is connected to specific and sensitive detector systems, spectrafluorimeter, diode detector, electrochemical detector as other hyphernated systems HPLC-MS and HPLC-NMR, are the basic elements on which is based such wide and effective application of the HPLC method. The purpose high performance liquid chromatography (HPLC) analysis of any drugs is to confirm the identity of a drug and provide quantitative results and also to monitor the progress of the therapy of a disease.1) Measuring presented on the Fig. 1. is chromatogram obtained for the plasma of depressed patients 12 h before oral administration of dexamethasone. It may also be used to further our understanding of the normal and disease process in the human body trough biomedical and therapeutically research during investigation before of the drugs registration. The analyses of drugs and metabolites in biological fluids, particularly plasma, serum or urine is one of the most demanding but one of the most common uses of high performance of liquid chromatography. Blood, plasma or serum contains numerous endogenous

Development of intelligent photomultipliers for the JUNO detector

Energy Technology Data Exchange (ETDEWEB)

Lenz, Florian; Meloni, Marta; Soiron, Michael; Stahl, Achim; Steinmann, Jochen; Wiebusch, Christopher [III. Physikalisches Institut B, RWTH Aachen University, 52056 Aachen (Germany)

2016-07-01

The JUNO experiment will be a 20kt liquid scintillator neutrino detector near Kaiping, China, 50km from two nuclear power plants. Its main goal is the determination of the neutrino mass hierarchy from a precise measurement of the energy spectrum of neutrinos. Due to the detector size it is not possible to digitize the signal outside the detector cavern. Therefore FPGAs with a low-level reconstruction combined with a fast ADC mounted on the base will convert the PMTs into intelligent sensors. Advantages and disadvantages of this design are be discussed,and first measurements are shown.

Preliminary investigation of a technique to separate fission noble metals from fission-product mixtures

International Nuclear Information System (INIS)

Mellinger, G.B.; Jensen, G.A.

1982-08-01

A variation of the gold-ore fire assay technique was examined as a method for recovering Pd, Rh and Ru from fission products. The mixture of fission product oxides is combined with glass-forming chemicals, a metal oxide such as PbO (scavenging agent), and a reducing agent such as charcoal. When this mixture is melted, a metal button is formed which extracts the noble metals. The remainder cools to form a glass for nuclear waste storage. Recovery depended only on reduction of the scavenger oxide to metal. When such reduction was achieved, no difference in noble metal recovery efficiency was found among the scavengers studied (PbO, SnO, CuO, Bi 2 O 3 , Sb 2 O 3 ). Not all reducing agents studied, however, were able to reduce all scavenger oxides to metal. Only graphite would reduce SnO and CuO and allow noble metal recovery. The scavenger oxides Sb 2 O 3 , Bi 2 O 3 , and PbO, however, were reduced by all of the reducing agents tested. Similar noble metal recovery was found with each. Lead oxide was found to be the most promising of the potential scavengers. It was reduced by all of the reducing agents tested, and its higher density may facilitate the separation. Use of lead oxide also appeared to have no deterimental effect on the glass quality. Charcoal was identified as the preferred reducing agent. As long as a separable metal phase was formed in the melt, noble metal recovery was not dependent on the amount of reducing agent and scavenger oxide. High glass viscosities inhibited separation of the molten scavenger, while low viscosities allowed volatile loss of RuO 4 . A viscosity of approx. 20 poise at the processing temperature offered a good compromise between scavenger separation and Ru recovery. Glasses in which PbO was used as the scavenging agent were homogeneous in appearance. Resistance to leaching was close to that of certain waste glasses reported in the literature. 12 figures. 7 tables

Reverse phase high performance liquid chromatographic method development based on ultravioletvisible detector for the analysis of 1-hydroxypyrene (PAH biomarker) in human urine.

Science.gov (United States)

Kamal, Atif; Gulfraz, Mohammad; Anwar, Mohammad Asad; Malik, Riffat Naseem

2015-01-01

1-hydroxypyrene is an important biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs), which appears in the urine of exposed human subjects. In developing countries, where advanced instruments are not available, the importance of this biomarker demands convenient and sensitive methods for determination purposes. This study aimed at developing a methodology to quantify 1-hydroxypyrene (a biomarker of PAHs exposure) based on the UV-visible detector in the reverse phase high pressure liquid chromatography (HPLC). A 20 μl injection of sample was used for manual injection into the HPLC Shimadzu, equipped with the SPD-20 A UV-visible detector, the LC-20AT pump and the DGU-20A5 degasser. The C-18 column was used for the purpose of the analysis. The method showed a good linearity (the range: R2 = 0.979-0.989), and high detectability up to the nmol level. The average retention was 6.37, with the accuracy of 2%, and the percentage of recovery remained 108%. The overall performance of this method was comparable (in terms of detection sensitivity) and relatively better than previously reported studies using the HPLC system equipped with the UV-detector. This method is suitable and reliable for the detection/quantification of the 1-OHP in human urine samples, using the UV-detector, however, it is less sensitive as compared to the results of a florescence detector. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Two-phase Cryogenic Avalanche Detector with electroluminescence gap operated in argon doped with nitrogen

Energy Technology Data Exchange (ETDEWEB)

Bondar, A.; Buzulutskov, A. [Budker Institute of Nuclear Physics SB RAS, Lavrentiev avenue 11, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation); Dolgov, A. [Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation); Nosov, V.; Shekhtman, L.; Shemyakina, E.; Sokolov, A. [Budker Institute of Nuclear Physics SB RAS, Lavrentiev avenue 11, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogov street 2, 630090 Novosibirsk (Russian Federation)

2017-02-11

A two-phase Cryogenic Avalanche Detector (CRAD) with electroluminescence (EL) gap, operated in argon doped with a minor (49±7 ppm) admixture of nitrogen, has been studied. The EL gap was optically read out using cryogenic PMTs located on the perimeter of the gap. We present the results of the measurements of the N{sub 2} content, detector sensitivity to X-ray-induced signals, EL gap yield and electron lifetime in the liquid. The detector sensitivity, at a drift field in liquid Ar of 0.6 kV/cm, was measured to be 9 and 16 photoelectrons recorded at the PMTs per keV of deposited energy at 23 and 88 keV respectively. Such two-phase detectors, with enhanced sensitivity to the S2 (ionization-induced) signal, are relevant in the field of argon detectors for dark matter search and low energy neutrino detection.

Noble metals in cretaceous/tertiary sediments from El Kef

International Nuclear Information System (INIS)

Kuslys, M.; Kraehenbuehl, U.

1983-01-01

Sediments from El Kef, Tunisia, were analysed by RNAA for Au, Ir and Os. All three elements show a 10-20 fold enrichment at the Cretaceous/Tertiary boundary. This enrichment must be the result of the addition of material with a high concentration of noble metals. It is plausible that this exotic material has an extra-terrestrial origin. (orig.)

Noble metals in Cretaceous/Tertiary sediments from El Kef

International Nuclear Information System (INIS)

Kuslys, M.; Kraehenbuehl, U.

1983-01-01

Sediments from El Kef, Tunisia, were analysed by RNAA for Au, Ir and Os. All three elements show a 10-20 fold enrichment at the Cretaceous/Tertiary boundary. This enrichment must be the result of the addition of material with a high concentration of noble metals. It is plausible that this exotic material has an extraterrestrial origin. (orig.)

Rational design of binder-free noble metal/metal oxide arrays with nanocauliflower structure for wide linear range nonenzymatic glucose detection

KAUST Repository

Li, Zhenzhen; Xin, Yanmei; Zhang, Zhonghai; Wu, Hongjun; Wang, Peng

2015-01-01

One-dimensional nanocomposites of metal-oxide and noble metal were expected to present superior performance for nonenzymatic glucose detection due to its good conductivity and high catalytic activity inherited from noble metal and metal oxide

Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

Science.gov (United States)

A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

Interaction between Nafion ionomer and noble metal catalyst for PEMFCs

DEFF Research Database (Denmark)

Andersen, Shuang Ma

The implement of polymer impregnation in electrode structure (catalyst layer) decreasing the noble metal catalyst loading by a factor of ten , , is one of the essential mile stones in the evolution of Proton Exchange Membrane Fuel Cells’ development among the application of catalyst support and e...

Not so Noble-Radon in the Environment and Associated Health ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 7. Radon: Not so Noble-Radon in the Environment and Associated Health Problems. Deepanjan Majumdar. General Article Volume 5 Issue 7 July 2000 pp 44-55. Fulltext. Click here to view fulltext PDF. Permanent link:

Scintillating fiber detector development for the SSC: Annual progress report

International Nuclear Information System (INIS)

Ruchti, R.C.

1989-01-01

During the past year, considerable effort has been applied to the development of scintillating fiber detectors in several areas: new scintillation liquids and studies of their fluorescence properties; new fluorescent dyes based on non-intramolecular proton transfer; new dyes based on intramolecular proton transfer; incorporation of these new dyes in plastic (polystyrene) and liquid scintillation solutions; development of small cross section glass capillaries for the containment of liquid scintillators; studies of waveguide characteristics; studies of image intensifier phosphor screen characteristics; initial steps to form a collaboration to study and develop appropriate new properties of the Solid State Photomultiplier; construction of a new laboratory at Notre Dame to enhance our capabilities for further measurements and studies; and organization of and execution of a Workshop on Scintillating Fiber Detector Development for the SSC, held at Fermilab, November 14--16, 1988

Radiative response on massive noble gas injection for Runaway suppression in disruptive plasmas

International Nuclear Information System (INIS)

Reiter, Bernhard

2010-01-01

The most direct way to avoid the formation of a relativistic electron beam under the influence of an electric field in a highly conducting plasma, is to increase the electron density to a value, where the retarding collisional force balances the accelerating one. In a disruptive tokamak plasma, rapid cooling induces a high electric field, which could easily violate the force balance and push electrons into the relativistic regime. Such relativistic electrons, the so-called runaways, accumulate many MeV's and can cause substantial damage when they hit the wall. This thesis is based on the principle of rapidly fueling the plasma for holding the force balance even under the influence of high electric fields typical for disruptions. The method of injecting high amounts of noble gas particles into the plasma from a close distance is put into practice in the ASDEX Upgrade fusion test facility. In the framework of this thesis, a multi-channel photometer system based on 144 AXUV detectors in a toroidal stereo measurement setup was built. It kept its promise to provide new insights into the transport mechanisms in a disruptive plasma under the influence of strong radiative interaction dynamics between injected matter and the hot plasma.

MO-A-BRD-01: An Investigation of the Dynamic Response of a Novel Acousto-Optic Liquid Crystal Detector for Full-Field Transmission Ultrasound Breast Imaging

International Nuclear Information System (INIS)

Rosenfield, J.R.; La Riviere, P.J.; Sandhu, J.S.

2014-01-01

Purpose: To characterize the dynamic response of a novel acousto-optic (AO) liquid crystal detector for high-resolution transmission ultrasound breast imaging. Transient and steady-state lesion contrast were investigated to identify optimal transducer settings for our prototype imaging system consistent with the FDA limits of 1 W/cm 2 and 50 J/cm 2 on the incident acoustic intensity and the transmitted acoustic energy flux density. Methods: We have developed a full-field transmission ultrasound breast imaging system that uses monochromatic plane-wave illumination to acquire projection images of the compressed breast. The acoustic intensity transmitted through the breast is converted into a visual image by a proprietary liquid crystal detector operating on the basis of the AO effect. The dynamic response of the AO detector in the absence of an imaged breast was recorded by a CCD camera as a function of the acoustic field intensity and the detector exposure time. Additionally, a stereotactic needle biopsy breast phantom was used to investigate the change in opaque lesion contrast with increasing exposure time for a range of incident acoustic field intensities. Results: Using transducer voltages between 0.3 V and 0.8 V and exposure times of 3 minutes, a unique one-to-one mapping of incident acoustic intensity to steady-state optical brightness in the AO detector was observed. A transfer curve mapping acoustic intensity to steady-state optical brightness shows a high-contrast region analogous to the linear portion of the Hurter-Driffield curves of radiography. Using transducer voltages between 1 V and 1.75 V and exposure times of 90 s, the lesion contrast study demonstrated increasing lesion contrast with increasing breast exposure time and acoustic field intensity. Lesion-to-background contrast on the order of 0.80 was observed. Conclusion: Maximal lesion contrast in our prototype system can be obtained using the highest acoustic field intensity and the longest breast

Mitochondrial cytochrome oxidase I gene analysis indicates a restricted genetic background in Finnish noble crayfish (Astacus astacus stocks

Directory of Open Access Journals (Sweden)

Makkonen J.

2015-01-01

Full Text Available The IUCN Red List indexes the noble crayfish (Astacus astacus as vulnerable, with a declining population trend. The main threats to the species are the crayfish plague caused by the oomycete Aphanomyces astaci and the introduced North American crayfish that act as the carriers of this disease. In Finland, the noble crayfish is considered as a native species, which original distribution area covers the southern part of the country, but the species distribution has been dispersed to cover almost the whole country. The aim of this study was to survey the genetic diversity among the Finnish noble crayfish populations. The mitochondrial cytochrome oxidase I (COI-gene was sequenced from 742 individuals representing 59 populations from Finland and Estonia. As a result, only a single haplotype was found. Based on these results, the genetic diversity of noble crayfish in its Northern distribution range is remarkably low. The observed lack of variation can result from several mechanisms including small size of the founder population and the intense spreading of the species by manmade stockings. The restricted diversity can also be caused by eradication of the original populations due to crayfish plague epidemics and spreading of the invasive crayfish species carrying the crayfish plague. It is also possible that all contemporary Finnish noble crayfish populations originate from stockings with no variation in respect to COI-gene.

DARWIN: towards the ultimate dark matter detector

Science.gov (United States)

Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Amsler, C.; Aprile, E.; Arazi, L.; Arneodo, F.; Barrow, P.; Baudis, L.; Benabderrahmane, M. L.; Berger, T.; Beskers, B.; Breskin, A.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; Diglio, S.; Drexlin, G.; Duchovni, E.; Erdal, E.; Eurin, G.; Ferella, A.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Di Gangi, P.; Di Giovanni, A.; Galloway, M.; Garbini, M.; Geis, C.; Glueck, F.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hannen, V.; Hogenbirk, E.; Howlett, J.; Hilk, D.; Hils, C.; James, A.; Kaminsky, B.; Kazama, S.; Kilminster, B.; Kish, A.; Krauss, L. M.; Landsman, H.; Lang, R. F.; Lin, Q.; Linde, F. L.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morå, K. D.; Morteau, E.; Murra, M.; Naganoma, J.; Newstead, J. L.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; de Perio, P.; Persiani, R.; Piastra, F.; Piro, M. C.; Plante, G.; Rauch, L.; Reichard, S.; Rizzo, A.; Rupp, N.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schumann, M.; Schreiner, J.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Silva, M. C.; Simgen, H.; Sissol, P.; von Sivers, M.; Thers, D.; Thurn, J.; Tiseni, A.; Trotta, R.; Tunnell, C. D.; Valerius, K.; Vargas, M. A.; Wang, H.; Wei, Y.; Weinheimer, C.; Wester, T.; Wulf, J.; Zhang, Y.; Zhu, T.; Zuber, K.

2016-11-01

DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment for the direct detection of dark matter using a multi-ton liquid xenon time projection chamber at its core. Its primary goal will be to explore the experimentally accessible parameter space for Weakly Interacting Massive Particles (WIMPs) in a wide mass-range, until neutrino interactions with the target become an irreducible background. The prompt scintillation light and the charge signals induced by particle interactions in the xenon will be observed by VUV sensitive, ultra-low background photosensors. Besides its excellent sensitivity to WIMPs above a mass of 5 GeV/c2, such a detector with its large mass, low-energy threshold and ultra-low background level will also be sensitive to other rare interactions. It will search for solar axions, galactic axion-like particles and the neutrinoless double-beta decay of 136Xe, as well as measure the low-energy solar neutrino flux with detect galactic supernovae. We present the concept of the DARWIN detector and discuss its physics reach, the main sources of backgrounds and the ongoing detector design and R&D efforts.

DARWIN: towards the ultimate dark matter detector

Energy Technology Data Exchange (ETDEWEB)

Aalbers, J.; Breur, P.A.; Brown, A. [Nikhef and the University of Amsterdam, Amsterdam (Netherlands); Agostini, F. [Department of Physics and Astrophysics, University of Bologna and INFN-Bologna, Bologna (Italy); Alfonsi, M.; Beskers, B. [Institut für Physik and Exzellenzcluster PRISMA, Johannes Gutenberg-Universität Mainz, Mainz (Germany); Amaro, F.D. [Department of Physics, University of Coimbra, Coimbra (Portugal); Amsler, C. [Albert Einstein Center for Fundamental Physics, Universität Bern, Bern (Switzerland); Aprile, E. [Physics Department, Columbia University, New York, NY (United States); Arazi, L.; Breskin, A.; Budnik, R. [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot (Israel); Arneodo, F.; Benabderrahmane, M.L. [New York University Abu Dhabi (United Arab Emirates); Barrow, P.; Baudis, L. [Physik-Institut, Universität Zürich, Zürich (Switzerland); Berger, T.; Brown, E. [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY (United States); Bruenner, S. [Max-Planck-Institut für Kernphysik, Heidelberg (Germany); Bruno, G., E-mail: lior.arazi@weizmann.ac.il, E-mail: laura.baudis@physik.uzh.ch, E-mail: amos.breskin@weizmann.ac.il, E-mail: decowski@nikhef.nl, E-mail: marc.schumann@lhep.unibe.ch [INFN-Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, L' Aquila (Italy); and others

2016-11-01

DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment for the direct detection of dark matter using a multi-ton liquid xenon time projection chamber at its core. Its primary goal will be to explore the experimentally accessible parameter space for Weakly Interacting Massive Particles (WIMPs) in a wide mass-range, until neutrino interactions with the target become an irreducible background. The prompt scintillation light and the charge signals induced by particle interactions in the xenon will be observed by VUV sensitive, ultra-low background photosensors. Besides its excellent sensitivity to WIMPs above a mass of 5 GeV/ c {sup 2}, such a detector with its large mass, low-energy threshold and ultra-low background level will also be sensitive to other rare interactions. It will search for solar axions, galactic axion-like particles and the neutrinoless double-beta decay of {sup 136}Xe, as well as measure the low-energy solar neutrino flux with < 1% precision, observe coherent neutrino-nucleus interactions, and detect galactic supernovae. We present the concept of the DARWIN detector and discuss its physics reach, the main sources of backgrounds and the ongoing detector design and R and D efforts.

Liquid metal-to-gas leak-detection instruments

International Nuclear Information System (INIS)

Matlin, E.; Witherspoon, J.E.; Johnson, J.L.

1982-01-01

It is desirable for liquid-metal-cooled reactors that small liquid metal-to-gas leaks be reliably detected. Testing has been performed on a number of detection systems to evaluate their sensitivity, response time, and performance characteristics. This testing has been scheduled in three phases. The first phase was aimed at screening out the least suitable detectors and optimizing the performance of the most promising. In the second phase, candidates were tested in a 1500 ft 3 walk-in type enclosure in which leaks were simulated on 24-in. and 3-in. piping. In the third phase of testing, selected type detectors were tested in the 1500-ft 3 enclosure with Clinch River Breeder Reactor Plant (CRBRP) pipe insulation configurations and detector tubing configuration with cell gas recirculation simulated. Endurance testing of detection equipment was also performed as part of this effort. Test results have been shown that aerosol-type detectors will reliably detect leaks as small as a few grams per hour when sampling pipe insulation annuli

SISAK liquid-liquid extraction experiments with preseparated {sup 257}Rf

Energy Technology Data Exchange (ETDEWEB)

Omtvedt, Jon Petter; Alstad, J.; Breivik, H. [University of Oslo, Department of Chemistry, Oslo (NO)] (and others)

2002-06-01

The SISAK liquid-liquid extraction system was used to extract 4.0-s {sup 257}Rf. The {sup 257}Rf was produced in the reaction {sup 208}Pb({sup 50}Ti, 1n){sup 257}Rf with 237-MeV beam energy on target, separated in the Berkeley Gas-filled Separator (BGS) and transferred to a gas jet using the Recoil Transfer Chamber (RTC). The activity delivered by the gas jet was dissolved in 6-M HNO{sub 3} and Rf was extracted into 0.25-M dibutyl-phosphoric acid in toluene. This was the first time a transactinide, i.e., an element with Z{>=}104, was extracted and unequivocally identified by the SISAK system. Thus, this pilot experiment demonstrates that the fast liquid-liquid extraction system SISAK, in combination with liquid-scintillation detectors, can be used for investigating the chemical properties of the transactinides. The extraction result is in accordance with the behaviour shown by the Rf group IV homologues Zr and Hf. (author)

The preparation of primary standard solutions for each of the noble metals

International Nuclear Information System (INIS)

Mallett, R.C.; Wall, G.J.; Jones, E.A.; Royal, S.J.

1977-01-01

A revised method for the preparation of primary standard solutions for each of the noble metals is described. It is now recommended that standard noble-metal solutions should be made from the pure metals and not from salts as previously described. Metals should have a certified purity of 99,95 per cent or better, and the purity should be confirmed by analysis, the techniques of emission spectography or spark-source mass spectrography being used. After the metals have been dissolved, the solutions are made up to volume and the metal content of the standard solutions is checked. For most instrumental techniques for which the standards are intended, the check analysis should be within 0,3 per cent of the certified value

Visible light active TiO2 films prepared by electron beam deposition of noble metals

International Nuclear Information System (INIS)

Hou Xinggang; Ma Jun; Liu Andong; Li Dejun; Huang Meidong; Deng Xiangyun

2010-01-01

TiO 2 films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO 2 films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO 2 is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO 2 films by this method is affected by the concentration of impregnating solution.

Photosensitive Gaseous Detectors for Cryogenic Temperature Applications

CERN Document Server

Periale, L; Iacobaeus, C; Lund-Jensen, B; Picchi, P; Pietropaolo, F

2007-01-01

There are several proposals and projects today for building LXe Time Projection Chambers (TPCs) for dark matter search. An important element of these TPCs are the photomultipliers operating either inside LXe or in vapors above the liquid. We have recently demonstrated that photosensitive gaseous detectors (wire type and hole-type) can operate perfectly well until temperatures of LN2. In this paper results of systematic studies of operation of the photosensitive version of these detectors (combined with reflective or semi-transparent CsI photocathodes) in the temperature interval of 300-150 K are presented. In particular, it was demonstrated that both sealed and flushed by a gas detectors could operate at a quite stable fashion in a year/time scale. Obtained results, in particular the long-term stability of photosensitive gaseous detectors, strongly indicate that they can be cheap and simple alternatives to photomultipliers or avalanche solid-state detectors in LXe TPC applications.

Organic liquid scintillation detectors for on-the-fly neutron/gamma alarming and radionuclide identification in a pedestrian radiation portal monitor

Science.gov (United States)

Paff, Marc Gerrit; Ruch, Marc L.; Poitrasson-Riviere, Alexis; Sagadevan, Athena; Clarke, Shaun D.; Pozzi, Sara

2015-07-01

We present new experimental results from a radiation portal monitor based on the use of organic liquid scintillators. The system was tested as part of a 3He-free radiation portal monitor testing campaign at the European Commission's Joint Research Centre in Ispra, Italy, in February 2014. The radiation portal monitor was subjected to a wide range of test conditions described in ANSI N42.35, including a variety of gamma-ray sources and a 20,000 n/s 252Cf source. A false alarm test tested whether radiation portal monitors ever alarmed in the presence of only natural background. The University of Michigan Detection for Nuclear Nonproliferation Group's system triggered zero false alarms in 2739 trials. It consistently alarmed on a variety of gamma-ray sources travelling at 1.2 m/s at a 70 cm source to detector distance. The neutron source was detected at speeds up to 3 m/s and in configurations with up to 8 cm of high density polyethylene shielding. The success of on-the-fly radionuclide identification varied with the gamma-ray source measured as well as with which of two radionuclide identification methods was used. Both methods used a least squares comparison between the measured pulse height distributions to library spectra to pick the best match. The methods varied in how the pulse height distributions were modified prior to the least squares comparison. Correct identification rates were as high as 100% for highly enriched uranium, but as low as 50% for 241Am. Both radionuclide identification algorithms produced mixed results, but the concept of using liquid scintillation detectors for gamma-ray and neutron alarming in radiation portal monitor was validated.

Final results for the neutron detector efficiencies

International Nuclear Information System (INIS)

Zhou Zuying; Tang Hongqing; Qi Bujia; Du Yanfeng; Zhou Chenwei; Xia Haihong; Chen Zemin; Chen Zhenpeng; Chen Yingtang

1998-01-01

Final results for neutron detector efficiencies of a liquid organic scintillator are presented. The comparisons of efficiency results to calculations with discrimination against γ-rays and without n-γ discrimination are shown out and discussed. The measured relative neutron detection efficiency of a liquid organic scintillator with the PSD constraint active is in good agreement with SCINFUL calculations from 9 to 40 Mev and NEFF7 calculations from 9 to 20 Mev, the upper limit of the latter code

Performance evaluation of a biodiesel fuelled transportation engine retrofitted with a non-noble metal catalysed diesel oxidation catalyst for controlling unregulated emissions.

Science.gov (United States)

Shukla, Pravesh Chandra; Gupta, Tarun; Agarwal, Avinash Kumar

2018-02-15

In present study, engine exhaust was sampled for measurement and analysis of unregulated emissions from a four cylinder transportation diesel engine using a state-of-the-art FTIR (Fourier transform infrared spectroscopy) emission analyzer. Test fuels used were Karanja biodiesel blend (B20) and baseline mineral diesel. Real-time emission measurements were performed for raw exhaust as well as exhaust sampled downstream of the two in-house prepared non-noble metal based diesel oxidation catalysts (DOCs) and a baseline commercial DOC based on noble metals. Two prepared non-noble metal based DOCs were based on Co-Ce mixed oxide and Lanthanum based perovskite catalysts. Perovskite based DOC performed superior compared to Co-Ce mixed oxide catalyst based DOC. Commercial noble metal based DOC was found to be the most effective in reducing unregulated hydrocarbon emissions in the engine exhaust, followed by the two in-house prepared non-noble metal based DOCs. Copyright © 2017 Elsevier B.V. All rights reserved.

Scintillating liquid xenon calorimeter for precise electron/photon/jet physics at high energy high luminosity hadron colliders

International Nuclear Information System (INIS)

Chen, M.; Luckey, D.; Pelly, D.; Shotkin, S.; Sumorok, K.; Wadsworth, B.; Yan, X.J.; You, C.; Zhang, X.; Chen, E.G.; Gaudreau, M.P.J.; Montgomery, D.B.; Sullivan, J.D.; Bolozdynya, A.; Chernyshev, V.; Goritchev, P.; Khovansky, V.; Kouchenkov, A.; Kovalenko, A.; Lebedenko, V.; Vinogradov, V.A.; Epstein, V.; Zeldovich, S.; Krasnokutsky, R.; Shuvalov, R.; Aprile, E.; Mukherjee, R.; Suzuki, M.; Moulsen, M.; Sugimoto, S.; Okada, K.; Fujino, T.; Matsuda, T.; Miyajima, M.; Doke, T.; Kikuchi, J.; Hitachi, A.; Kashiwagi, T.; Nagasawa, Y.; Ichinose, H.; Ishida, N.; Nakasugi, T.; Ito, T.; Masuda, K.; Shibamura, E.; Wallraff, W.; Vivargent, M.; Mutterer, M.; Chen, H.S.; Tang, H.W.; Tung, K.L.; Ding, H.L.; Takahashi, T.

1990-01-01

The authors use αs well as e, π, p, d and heavy ion beams to test prototype scintillating liquid xenon detectors, with large UV photodiodes and fast amplifiers submersed directly in liquid xenon. The data show very large photoelectron yields (10 7 /GeV) and high energy resolution (σ(E)/E 1.6 GeV). The α spectra are stable over long term and can be used to calibrate the detectors. Full size liquid xenon detectors have been constructed, to study cosmic μ's and heavy ions. The authors report the progress on the design and construction of the 5 x 5 and 11 x 11 cell liquid xenon detectors which will be tested in high energy beams to determine the e/π ratio. The authors describe the design and the unique properties of the proposed scintillating LXe calorimeter for the SSC

Simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation by ultra-high performance liquid chromatography coupled with nano quantity analyte detector

OpenAIRE

Honggen Zhang; Zhenyu Wang; Oscar Liu

2016-01-01

A novel method for simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation was developed using ultra-high performance liquid chromatography coupled with a nano quantitation analytical detector (UHPLC–NQAD). All components in kolliphor HS15 and miglyol 812 were well separated on an Acquity BEH C18 column. Mobile phase A was 0.1% trifluoroacetic acid (TFA) in water and mobile phase B was acetonitrile. A gradient elution sequence was programed initially with 60%...

Behaviour of quadrupole mass spectrometer towards noble gases

International Nuclear Information System (INIS)

Hasibullah

1980-01-01

This paper describes a quadrupole mass spectrometric set-up for noble gas analysis with its potential application to material accountancy at the input accountability tank of a reprocessing facility. Linear dependence of ion source pressure on the inlet pressure was considered to be practicable criterion for the functionality of the instrument. Short term and long term sensitivity variations have also been discussed. No memory effect was observed under the experimental conditions. (author)

Detectors and flux instrumentation for future neutrino facilities

CERN Document Server

Abe, T.; Andreopoulos, C.; Ankowski, A.; Badertscher, A.; Battistoni, G.; Blondel, A.; Bouchez, J.; Bross, A.; Bueno, A.; Camilleri, L.; Campagne, Jean-Eric; Cazes, A.; Cervera-Villanueva, A.; De Lellis, G.; Di Capua, F.; Ellis, Malcolm; Ereditato, A.; Esposito, L.S.; Fukushima, C.; Gschwendtner, E.; Gomez-Cadenas, J.J.; Iwasaki, M.; Kaneyuki, K.; Karadzhov, Y.; Kashikhin, V.; Kawai, Y.; Komatsu, M.; Kozlovskaya, E.; Kudenko, Y.; Kusaka, A.; Kyushima, H.; Longhin, A.; Marchionni, A.; Marotta, A.; McGrew, C.; Menary, S.; Meregaglia, A.; Mezzeto, M.; Migliozzi, P.; Mondal, N.K.; Montanari, C.; Nakadaira, T.; Nakamura, M.; Nakumo, H.; Nakayama, H.; Nelson, J.; Nowak, J.; Ogawa, S.; Peltoniemi, J.; Pla-Dalmau, A.; Ragazzi, S.; Rubbia, A.; Sanchez, F.; Sarkamo, J.; Sato, O.; Selvi, M.; Shibuya, H.; Shozawa, M.; Sobczyk, J.; Soler, F.J.P.; Strolin, Paolo Emilio; Suyama, M.; Tanak, M.; Terranova, F.; Tsenov, R.; Uchida, Y.; Weber, A.; Zlobin, A.

2009-01-01

This report summarises the conclusions from the detector group of the International Scoping Study of a future Neutrino Factory and Super-Beam neutrino facility. The baseline detector options for each possible neutrino beam are defined as follows: 1. A very massive (Megaton) water Cherenkov detector is the baseline option for a sub-GeV Beta Beam and Super Beam facility. 2. There are a number of possibilities for either a Beta Beam or Super Beam (SB) medium energy facility between 1-5 GeV. These include a totally active scintillating detector (TASD), a liquid argon TPC or a water Cherenkov detector. 3. A 100 kton magnetized iron neutrino detector (MIND) is the baseline to detect the wrong sign muon final states (golden channel) at a high energy (20-50 GeV) neutrino factory from muon decay. A 10 kton hybrid neutrino magnetic emulsion cloud chamber detector for wrong sign tau detection (silver channel) is a possible complement to MIND, if one needs to resolve degeneracies that appear in the $\\delta$-$\\theta_{13}$...

The thermodynamics of pyrochemical processes for liquid metal reactor fuel cycles

International Nuclear Information System (INIS)

Johnson, I.

1987-01-01

The thermodynamic basis for pyrochemical processes for the recovery and purification of fuel for the liquid metal reactor fuel cycle is described. These processes involve the transport of the uranium and plutonium from one liquid alloy to another through a molten salt. The processes discussed use liquid alloys of cadmium, zinc, and magnesium and molten chloride salts. The oxidation-reduction steps are done either chemically by the use of an auxiliary redox couple or electrochemically by the use of an external electrical supply. The same basic thermodynamics apply to both the salt transport and the electrotransport processes. Large deviations from ideal solution behavior of the actinides and lanthanides in the liquid alloys have a major influence on the solubilities and the performance of both the salt transport and electrotransport processes. Separation of plutonium and uranium from each other and decontamination from the more noble fission product elements can be achieved using both transport processes. The thermodynamic analysis is used to make process design computations for different process conditions

Chemical reactivity of the compressed noble gas atoms and their ...

Indian Academy of Sciences (India)

Attempts are made to gain insights into the effect of confinement of noble gas atoms on their various reactivity indices. Systems become harder, less polarizable and difficult to excite as the compression increases. Ionization also causes similar effects. A quantum fluid density functional technique is adopted in order to study ...

The Origin of Noble Gas Isotopic Heterogeneity in Icelandic Basalts

Science.gov (United States)

Dixon, E. T.; Honda, M.; McDougall, I.

2001-01-01

Two models for generation of heterogeneous He, Ne and Ar isotopic ratios in Icelandic basalts are evaluated using a mixing model and the observed noble gas elemental ratios in Icelandic basalts,Ocean island Basalt (OIBs) and Mid-Ocean Ridge Basalt (MORBs). Additional information is contained in the original extended abstract.

Cryogenic method for measuring nuclides and fission gases

Science.gov (United States)

Perdue, P.T.; Haywood, F.F.

1980-05-02

A cryogenic method is provided for determining airborne gases and particulates from which gamma rays are emitted. A special dewar counting vessel is filled with the contents of the sampling flask which is immersed in liquid nitrogen. A vertically placed sodium-iodide or germanium-lithium gamma-ray detector is used. The device and method are of particular use in measuring and identifying the radioactive noble gases including emissions from coal-fired power plants, as well as fission gases released or escaping from nuclear power plants.

Preliminary results on bubble detector as personal neutron dosemeter

International Nuclear Information System (INIS)

Ponraju, D.; Krishnan, H.; Viswanathan, S.; Indira, R.

2011-01-01

The bubble detector is demonstrated as one of the best suitable neutron detectors for neutron dose rate measurements in the presence of high-intense gamma fields. Immobilisation of a volatile liquid in a superheated state and achieving uniform distribution of tiny superheated droplets were a practical challenge. A compact and reusable bubble detector with high neutron sensitivity has been developed at the Indira Gandhi Centre for Atomic Research by immobilising the superheated droplets in a suitable polymer matrix. Two types of bubble detectors have been successfully developed, one by incorporating isobutane for measuring fast neutron and another by incorporating Freon-12 for both fast and thermal neutron. The performance of the detector has been tested using 5 Ci Am-Be neutron source and the results are described. (authors)

Development of supported noble metal catalyst for U(VI) to U(IV) reduction

International Nuclear Information System (INIS)

Tyagi, Deepak; Varma, Salil; Bhattacharyya, K.; Tripathi, A.K.; Bharadwaj, S.R.; Jain, V.K.; Sahu, Avinash; Vincent, Tessy; Jagatap, B.N.; Wattal, P.K.

2015-01-01

Uranium-plutonium separation is an essential step in the PUREX process employed in spent nuclear fuel reprocessing. This partitioning in the PUREX process is achieved by selective reduction of Pu(IV) to Pu(III) using uranous nitrate as reductant and hydrazine as stabilizer. Currently in our Indian reprocessing plants, the requirement of uranous nitrate is met by electrolytic reduction of uranyl nitrate. This process, however, suffers from a major drawback of incomplete reduction with a maximum conversion of ~ 60%. Catalytic reduction of U(VI) to U(IV) is being considered as one of the promising alternatives to the electro-reduction process due to fast kinetics and near total conversion. Various catalysts involving noble metals like platinum (Adams catalyst, Pt/Al 2 O 3 , Pt/SiO 2 etc.) have been reported for the reduction. Sustained activity and stability of the catalyst under harsh reaction conditions are still the issues that need to be resolved. We present here the results on zirconia supported noble metal catalyst that is developed in BARC for reduction of uranyl nitrate to uranous nitrate. Supported noble metal catalysts with varying metal loadings (0.5 - 2 wt%) were prepared via support precipitation and noble metal impregnation. The green catalysts were reduced either by chemical reduction using hydrazine hydrate or by heating in hydrogen flow or combination of both the steps. These catalysts were characterized by various techniques such as, XRD, SEM, TEM, N 2 adsorption and H 2 chemisorption. Performance of these catalysts was evaluated for U(VI) to U(IV) reduction with uranyl nitrate feed using hydrazine as reductant. The results with the most active catalyst are named as 'BARC-CAT', which was developed in our lab. (author)

Search for the solar pp-neutrinos with an upgrade of CTF detector

International Nuclear Information System (INIS)

Smirnov, O.Yu.; Zajmidoroga, O.A.; Derbin, A.V.

2001-01-01

A possibility to use ultrapure liquid organic scintillator as a low energy solar neutrino detector is discussed. The detector with an active volume of 10 tons and 4π coverage will count 1.8 pp-neutrinos and 5.4 7 Be neutrinos per day with an energy threshold of 170 keV for the recoil electrons. The evaluation of the detector sensitivity and backgrounds is based on the results obtained by the Borexino collaboration with the Counting Test Facility (CTF). The detector can be build at the Italian Gran Sasso underground laboratory as an upgrade of the CTF detector using already developed technologies

Hydration of the Atlantis Massif: Halogen, Noble Gas and In-Situ δ18O Constraints

Science.gov (United States)

Williams, M. J.; Kendrick, M. A.; Rubatto, D.

2017-12-01

A combination of halogen (Cl, Br, I), noble gases (He, Ne, Ar, Kr and Xe) and in situ oxygen isotope analysis have been utilized to investigate the fluid-mobile element record of hydration and alteration processes at the Atlantis Massif (30°N on the Mid-Atlantic Ridge). The sample suite investigated includes serpentinite, talc-amphibole ± chlorite schist and hydrated gabbro recovered by seafloor drilling undertaken at sites on a transect across the Atlantis Massif during IODP Expedition 357. Serpentine mesh and veins analysed in-situ by SHRIMP SI exhibit δ18O from 6‰ down to ≈0‰, suggesting serpentinization temperatures of 150 to >280°C and water/rock ratios >5. Differences of 1.5-2.5‰ are observed between adjacent generations of serpentine, but the δ18O range is similar at each investigated drilling site. Halogen and noble gas abundances in serpentinites, talc-amphibole schist and hydrated gabbro have been measured by noble gas mass spectrometry of both irradiated and non-irradiated samples. Serpentinites contain low abundances of halogens and noble gases (e.g. 70-430 ppm Cl, 4.7-12.2 x 10-14 mol/g 36Ar) relative to other seafloor serpentinites. The samples have systematically different Br/Cl and I/Cl ratios related to their mineralogy. Serpentinites retain mantle-like Br/Cl with a wide variation in I/Cl that stretches toward seawater values. Talc-amphibole schists exhibit depletion of Br and I relative to Cl with increasing Cl abundances, suggesting tremolite exerts strong control on halogen abundance ratios. Serpentinites show no evidence of interaction with halogen-rich sedimentary pore fluids. Iodine abundances are variable across serpentinites, and are decoupled from Br and Cl; iodine enrichment (up to 530 ppb) is observed within relatively oxidised and clay-bearing samples. Serpentinized harzburgites exhibit distinct depletion of Kr and Xe relative to atmospheric 36Ar in seawater. Oxygen isotope compositions and low abundances of both halogens

A fence line noble gas monitoring system for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Grasty, R.L.; Hovgaard, J.; LaMarre, J.R

2001-07-01

A noble gas monitoring system has been installed at Ontario Power Generations' Pickering Nuclear Generating Station (PNGS) near Toronto, Canada. This monitoring system allows a direct measure of air kerma from external radiation instead of calculating this based on plant emission data and meteorological models. This has resulted in a reduction in the reported effective dose from external radiation by a factor of at least ten. The system consists of nine self-contained units, each with a 7.6 cm x 7.6 cm (3 inch x 3 inch) NaI(Tl) detector that is calibrated for air kerma. The 512-channel gamma ray spectral information is downloaded daily from each unit to a central computer where the data are stored and processed. A spectral stripping procedure is used to remove natural background variations from the spectral windows used to monitor xenon-133 ({sup 133}Xe), xenon-135 ({sup 135}Xe), argon-41 ({sup 41}Ar), and skyshine radiation from the use of radiography sources. Typical monthly minimum detection limits in air kerma are 0.3 nGy for {sup 133}Xe, 0.7 nGy for {sup 135}Xe, 3 nGy for {sup 41}Ar and 2 nGy for skyshine radiation. Based on 9 months of continuous operation, the annualised air kerma due to {sup 133}Xe, {sup 135}Xe and {sup 41}Ar and skyshine radiation were 7 nGy, 8 nGy, 26 nGy and 107 nGy respectively. (author)

The 4π neutron detector CARMEN

Energy Technology Data Exchange (ETDEWEB)

Ledoux, X., E-mail: Xavier.ledoux@ganil.fr [CEA/DAM/DIF, F-91297 Arpajon (France); GANIL, CEA/DRF-CNRS/IN2P3, Caen, F-14076 France (France); Laborie, J.-M.; Pras, P.; Lantuéjoul-Thfoin, I.; Varignon, C. [CEA/DAM/DIF, F-91297 Arpajon (France)

2017-02-01

CARMEN is a 4π neutron detector filled with a gadolinium-loaded liquid scintillator built to measure neutron multiplicity distributions. It is used to study fission and (n,xn) reactions. In addition to neutron multiplicity measurements, CARMEN can be used to measure neutron energy spectra with the time-of-flight technique, thanks to the time properties of the prompt signal. The detector, detection technique and efficiency determination are presented in detail. Two examples are also presented: the measurement of {sup 252}Cf spontaneous fission neutron multiplicity probability distribution and the measurement of the neutron energy spectrum emitted by an Am-Be radioactive source.