WorldWideScience

Sample records for neutron time-of-flight source

  1. Calibration of time of flight detectors using laser-driven neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Mirfayzi, S. R.; Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.; Green, A.; Alejo, A.; Jung, D. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Krygier, A. G.; Freeman, R. R. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Clarke, R. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Fuchs, J.; Vassura, L. [LULI, Ecole Polytechnique, CNRS, Route de Saclay, 91128 Palaiseau Cedex (France); Kleinschmidt, A.; Roth, M. [Institut für Kernphysik, Technische Universität Darmstadt, Schloßgartenstrasse 9, D-64289 Darmstadt,Germany (Germany); Morrison, J. T. [Propulsion Systems Directorate, Air Force Research Lab, Wright Patterson Air Force Base, Ohio 45433 (United States); Najmudin, Z.; Nakamura, H. [Blackett Laboratory, Department of Physics, Imperial College, London SW7 2AZ (United Kingdom); Norreys, P. [Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom); Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Oliver, M. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom); Zepf, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Helmholtz Institut Jena, D-07743 Jena (Germany); Borghesi, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Institute of Physics of the ASCR, ELI-Beamlines Project, Na Slovance 2, 18221 Prague (Czech Republic)

    2015-07-15

    Calibration of three scintillators (EJ232Q, BC422Q, and EJ410) in a time-of-flight arrangement using a laser drive-neutron source is presented. The three plastic scintillator detectors were calibrated with gamma insensitive bubble detector spectrometers, which were absolutely calibrated over a wide range of neutron energies ranging from sub-MeV to 20 MeV. A typical set of data obtained simultaneously by the detectors is shown, measuring the neutron spectrum emitted from a petawatt laser irradiated thin foil.

  2. A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives

    Science.gov (United States)

    Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

    2011-12-01

    AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at ˜10-50 Hz and emits ˜106n/pulse at a peak current of 100 kA. Both sources emit 2.45±0.1 MeV (DD) neutron pulses of ˜25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm3 in volume.

  3. A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert [Alameda Applied Sciences Corporation, 3077 Teagarden Street, San Leandro, CA 94577 (United States); Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin [XIA LLC, 31057 Genstar Road, Hayward, CA 94544 (United States); Lane, Stephen [NSF Center for Biophotonics and School of Medicine, University of California Davis, Sacramento CA, 95817 (United States)

    2011-12-13

    AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at {approx}10-50 Hz and emits {approx}10{sup 6}n/pulse at a peak current of 100 kA. Both sources emit 2.45{+-}0.1 MeV(DD) neutron pulses of {approx}25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm{sup 3} in volume.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-12-30

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-12

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

  6. Concept for a time-of-flight Small Angle Neutron Scattering instrument at the European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Jaksch, S. [ESS Design Update Programme – Germany, Forschungszentrum Jülich GmbH, Jülich (Germany); Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching (Germany); Martin-Rodriguez, D. [ESS Design Update Programme – Germany, Forschungszentrum Jülich GmbH, Jülich (Germany); Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching (Germany); Neutron Optics and Shielding Group, European Spallation Source AB, Lund (Sweden); Ostermann, A. [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) at Heinz Maier-Leibnitz Zentrum, Technische Universität Muünchen, Garching (Germany); Jestin, J. [Laboratoire Léon Brillouin, LLB, CEA—Saclay, Gif sur Yvette cedex (France); Duarte Pinto, S.; Bouwman, W.G. [Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Uher, J. [Amsterdam Scientific Instruments, Amsterdam (Netherlands); Engels, R. [Zentralinstitut für Elektronik (ZEA-2), Forschungszentrum Jülich GmbH, Jülich (Germany); Frielinghaus, H. [ESS Design Update Programme – Germany, Forschungszentrum Jülich GmbH, Jülich (Germany); Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching (Germany)

    2014-10-21

    A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards µm and tens of µm, respectively. Two 1 m{sup 2} area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.

  7. Concept for a Time-of-Flight Small Angle Neutron Scattering Instrument at the European Spallation Source

    CERN Document Server

    Jaksch, S; Ostermann, A; Jestin, J; Pinto, S Duarte; Bouwman, W G; Uher, J; Engels, R; Kemmerling, G; Hanslik, R; Frielinghaus, H

    2014-01-01

    A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards um and tens of um, respectively. Two 1m2 area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.

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

    CERN Document Server

    Novopoltsev, M I

    2010-01-01

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

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

    CERN Multimedia

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

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

  10. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    DEFF Research Database (Denmark)

    Rasmussen, N. G.; Simeoni, G. G.; Lefmann, K.

    2016-01-01

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (a...

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

    Science.gov (United States)

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

    2008-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

  13. Data reduction for time-of-flight small-angle neutron scattering with virtual neutrons

    Science.gov (United States)

    Du, Rong; Tian, Haolai; Zuo, Taisen; Tang, Ming; Yan, Lili; Zhang, Junrong

    2017-09-01

    Small-angle neutron scattering (SANS) is an experimental technique to detect material structures in the nanometer to micrometer range. The solution of the structural model constructed from SANS strongly depends on the accuracy of the reduced data. The time-of-flight (TOF) SANS data are dependent on the wavelength of the pulsed neutron source. Therefore, data reduction must be handled very carefully to transform measured neutron events into neutron scattering intensity. In this study, reduction algorithms for TOF SANS data are developed and optimized using simulated data from a virtual neutron experiment. Each possible effect on the measured data is studied systematically, and suitable corrections are performed to obtain high-quality data. This work will facilitate scientific research and the instrument design at China Spallation Neutron Source.

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

    Science.gov (United States)

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

    2008-10-01

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

  15. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    Science.gov (United States)

    Rasmussen, N. G.; Simeoni, G. G.; Lefmann, K.

    2016-04-01

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (adjustable supermirror curvature) and the compact size (only 0.5 m long). We have simulated the neutron transport across the entire guide system. We present a detailed computer characterization of the existing device, along with the study of the factors mostly influencing the future improvement. We have optimized the simulated prototype as a function of the neutron wavelength, accounting also for all relevant features of a real instrument like the non-reflecting side edges. The results confirm the "chromatic" displacement of the focal point (flux density maximum) at fixed supermirror curvature, and the ability of a variable curvature to keep the focal point at the sample position. Our simulations are in excellent agreement with theoretical predictions and the experimentally measured beam profile. With respect to the possibility of a further upgrade, we find that supermirror coatings with m-values higher than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum.

  16. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, N.G. [Nanoscience Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark); Simeoni, G.G., E-mail: ggsimeoni@outlook.com [Heinz Maier-Leibnitz Zentrum (MLZ) and Physics Department, Technical University of Munich, D-85748 Garching (Germany); Lefmann, K. [Nanoscience Center, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark)

    2016-04-21

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (adjustable supermirror curvature) and the compact size (only 0.5 m long). We have simulated the neutron transport across the entire guide system. We present a detailed computer characterization of the existing device, along with the study of the factors mostly influencing the future improvement. We have optimized the simulated prototype as a function of the neutron wavelength, accounting also for all relevant features of a real instrument like the non-reflecting side edges. The results confirm the “chromatic” displacement of the focal point (flux density maximum) at fixed supermirror curvature, and the ability of a variable curvature to keep the focal point at the sample position. Our simulations are in excellent agreement with theoretical predictions and the experimentally measured beam profile. With respect to the possibility of a further upgrade, we find that supermirror coatings with m-values higher than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum.

  17. A radial collimator for a time-of-flight neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M. B.; Abernathy, D. L. [Quantum Condensed Matter Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Niedziela, J. L.; Loguillo, M. J.; Overbay, M. A. [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-08-15

    We have engineered and installed a radial collimator for use in the scattered beam of a neutron time-of-flight spectrometer at a spallation neutron source. The radial collimator may be used with both thermal and epithermal neutrons, reducing the detected scattering intensity due to material outside of the sample region substantially. The collimator is located inside of the sample chamber of the instrument, which routinely cycles between atmospheric conditions and cryogenic vacuum. The oscillation and support mechanism of the collimator allow it to be removed from use without breaking vacuum. We describe here the design and characterization of this radial collimator.

  18. A radial collimator for a time-of-flight neutron spectrometer

    Science.gov (United States)

    Stone, M. B.; Niedziela, J. L.; Loguillo, M. J.; Overbay, M. A.; Abernathy, D. L.

    2014-08-01

    We have engineered and installed a radial collimator for use in the scattered beam of a neutron time-of-flight spectrometer at a spallation neutron source. The radial collimator may be used with both thermal and epithermal neutrons, reducing the detected scattering intensity due to material outside of the sample region substantially. The collimator is located inside of the sample chamber of the instrument, which routinely cycles between atmospheric conditions and cryogenic vacuum. The oscillation and support mechanism of the collimator allow it to be removed from use without breaking vacuum. We describe here the design and characterization of this radial collimator.

  19. A time-of-flight detector for thermal neutrons from radiotherapy Linacs

    Science.gov (United States)

    Conti, V.; Bartesaghi, G.; Bolognini, D.; Mascagna, V.; Perboni, C.; Prest, M.; Scazzi, S.; Mozzanica, A.; Cappelletti, P.; Frigerio, M.; Gelosa, S.; Monti, A.; Ostinelli, A.; Giannini, G.; Vallazza, E.

    2007-10-01

    Boron Neutron Capture Therapy (BNCT) is a therapeutic technique exploiting the release of dose inside the tumour cell after a fission of a 10B nucleus following the capture of a thermal neutron. BNCT could be the treatment for extended tumors (liver, stomach, lung), radio-resistant ones (melanoma) or tumours surrounded by vital organs (brain). The application of BNCT requires a high thermal neutron flux (>5×108 n cm-2 s-1) with the correct energy spectrum (neutron energy reactors. The INFN PhoNeS (Photo Neutron Source) project is trying to produce such a neutron beam with standard radiotherapy Linacs, maximizing with a dedicated photo-neutron converter the neutrons produced by Giant Dipole Resonance by a high energy ( >8 MeV) photon beam. In this framework, we have developed a real-time detector to measure the thermal neutron time-of -flight to compute the flux and the energy spectrum. Given the pulsed nature of Linac beams, the detector is a single neutron counting system made of a scintillator detecting the photon emitted after the neutron capture by the hydrogen nuclei. The scintillator signal is sampled by a dedicated FPGA clock thus obtaining the exact arrival time of the neutron itself. The paper will present the detector and its electronics, the feasibility measurements with a Varian Clinac 1800/2100CD and comparison with a Monte Carlo simulation.

  20. Understanding inelastically scattered neutrons from water on a time-of-flight small-angle neutron scattering (SANS) instrument

    CERN Document Server

    Doa, Changwoo; Stanley, Christopher; Gallmeier, Franz X; Doucet, Mathieu; Smith, Gregory S

    2013-01-01

    It is generally assumed by most of the small-angle neutron scattering (SANS) user community that a neutrons energy is unchanged during SANS measurements. Here, the scattering from water, specifically light water, was measured on the EQ-SANS instrument, a time-of-flight SANS instrument located at the Spallation Neutron Source of Oak Ridge National Laboratory. A significant inelastic process was observed in the TOF spectra of neutrons scattered from water. Analysis of the TOF spectra from the sample showed that the scattered neutrons have energies consistent with room-temperature thermal energies (~20 meV) regardless of the incident neutron energy. With the aid of Monte Carlo particle transport simulations, we conclude that the thermalization process within the sample results in faster neutrons that arrive at the detector earlier than expected based on the incident neutron energies. This thermalization process impacts the measured SANS intensities in a manner that will ultimately be sample- and temperature-depe...

  1. Neutron Time of Flight Spectrometer for Velocity Selector Calibration

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Small angle neutron spectrometer on China Advanced Research Reactor (CARR) is located at neutron guide hall and is installed on the end of cold neutron guide. Velocity selector which can purify white light neutron beam into monochromatic neutron beam with wavelength

  2. Timing and position response of a block detector for fast neutron time-of-flight imaging

    Science.gov (United States)

    Laubach, M. A.; Hayward, J. P.; Zhang, X.; Cates, J. W.

    2014-11-01

    Our research effort seeks to improve the spatial and timing performance of a block detector made of a pixilated plastic scintillator (EJ-200), first demonstrated as part of Oak Ridge National Laboratory's Advanced Portable Neutron Imaging System. Improvement of the position and time response is necessary to achieve better resolution and contrast in the images of shielded special nuclear material. Time-of-flight is used to differentiate between gamma and different sources of neutrons (e.g., transmission and fission neutrons). Factors limiting the timing and position performance of the neutron detector have been revealed through simulations and measurements. Simulations have suggested that the degradation in the ability to resolve pixels in the neutron detector is due to those interactions occurring near the light guide. The energy deposition within the neutron detector is shown to affect position performance and imaging efficiency. This examination details how energy cuts improve the position performance and degrade the imaging efficiency. Measurements have shown the neutron detector to have a timing resolution of σ=238 ps. The majority of this timing uncertainty is from the depth-of-interaction (DOI) of the neutron which is confirmed by simulations and analytical calculations.

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

    NARCIS (Netherlands)

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

    1993-01-01

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

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

    Science.gov (United States)

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

    2017-02-01

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

  5. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    Energy Technology Data Exchange (ETDEWEB)

    Estrade, Alfredo [National Superconducting Cyclotron Laboratory (NSCL); Matos, M. [Louisiana State University; Schatz, Hendrik [Michigan State University, East Lansing; Amthor, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Bazin, D. [National Superconducting Cyclotron Laboratory (NSCL); Beard, Mary [University of Notre Dame, IN; Becerril, A. [National Superconducting Cyclotron Laboratory (NSCL); Brown, Edward [Michigan State University, East Lansing; Elliot, T [National Superconducting Cyclotron Laboratory (NSCL); Gade, A. [National Superconducting Cyclotron Laboratory (NSCL); Galaviz, D. [National Superconducting Cyclotron Laboratory (NSCL); George, S. [National Superconducting Cyclotron Laboratory (NSCL); Gupta, Sanjib [Indian Institute of Technology, Kanpur; Hix, William Raphael [ORNL; Lau, Rita [National Superconducting Cyclotron Laboratory (NSCL); Moeller, Peter [Los Alamos National Laboratory (LANL); Pereira, J. [National Superconducting Cyclotron Laboratory (NSCL); Portillo, M. [National Superconducting Cyclotron Laboratory (NSCL); Rogers, A. M. [National Superconducting Cyclotron Laboratory (NSCL); Shapira, Dan [ORNL; Smith, E. [Ohio State University; Stolz, A. [Michigan State University, East Lansing; Wallace, M. [Los Alamos National Laboratory (LANL); Wiescher, Michael [University of Notre Dame, IN

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Supercon- ducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the Sc Ni element range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of 61V, 63Cr, 66Mn, and 74Ni were measured for the first time with mass excesses of 30.510(890) MeV, 35.280(650) MeV, 36.900(790) MeV, and 49.210(990) MeV, respectively. With the measurement of the 66Mn mass, the location of the two dominant heat sources in the outer crust of accreting neutron stars, which exhibit so called superbursts, is now experimentally constrained. We find that the location of the 66Fe 66Mn electron capture transition occurs sig- nificantly closer to the surface than previously assumed because our new experimental Q-value is 2.1 MeV smaller than predicted by the FRDM mass model. The results also provide new insights into the structure of neutron-rich nuclei around N = 40.

  6. DNS: Diffuse scattering neutron time-of-flight spectrometer

    Directory of Open Access Journals (Sweden)

    Yixi Su

    2015-08-01

    Full Text Available DNS is a versatile diffuse scattering instrument with polarisation analysis operated by the Jülich Centre for Neutron Science (JCNS, Forschungszentrum Jülich GmbH, outstation at the Heinz Maier-Leibnitz Zentrum (MLZ. Compact design, a large double-focusing PG monochromator and a highly efficient supermirror-based polarizer provide a polarized neutron flux of about 107 n cm-2 s-1. DNS is used for the studies of highly frustrated spin systems, strongly correlated electrons, emergent functional materials and soft condensed matter.

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

    Science.gov (United States)

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

    2016-05-01

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

  8. Time-of-flight mass measurements for nuclear processes in neutron star crusts

    CERN Document Server

    Estrade, A; Schatz, H; Amthor, A M; Bazin, D; Beard, M; Becerril, A; Brown, E F; Cyburt, R; Elliot, T; Gade, A; Galaviz, D; George, S; Gupta, S S; Hix, W R; Lau, R; Lorusso, G; Moller, P; Pereira, J; Portillo, M; Rogers, A M; Shapira, D; Smith, E; Stolz, A; Wallace, M; Wiescher, M

    2011-01-01

    The location of electron capture heat sources in the crust of accreting neutron stars depends on the masses of extremely neutron-rich nuclei. We present first results from a new implementation of the time-of-flight technique to measure nuclear masses of rare isotopes at the National Superconducting Cyclotron Laboratory. The masses of 16 neutron-rich nuclei in the scandium -- nickel range were determined simultaneously, improving the accuracy compared to previous data in 12 cases. The masses of $^{61}${V}, $^{63}${Cr}, $^{66}${Mn}, and $^{74}${Ni} were measured for the first time with mass excesses of $-30.510(890)$ MeV, $-35.280(650)$ MeV, $-36.900(790)$ MeV, and $-49.210(990)$ MeV, respectively. With the measurement of the $^{66}$Mn mass, the locations of the two dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit superbursts are now experimentally constrained. We find that the location of the $^{66}$Fe$\\rightarrow^{66}$Mn electron capture transition occurs signi...

  9. Development and Applications of Time of Flight Neutron Depth Profiling

    Energy Technology Data Exchange (ETDEWEB)

    Bingham Cady; Kenan Unlu

    2005-03-17

    The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. For example, the subtle differences in spatial distribution and composition of many chemical species in the near surface region and across interfacial boundaries can significantly alter the electronic and optical properties of materials. A number of analytical techniques for depth profiling have been developed during the last two decades. neutron Depth Profiling (NDP) is one of the leading analytical techniques. The NDP is a nondestructive near surface technique that utilizes thermal/cold neutron beam to measure the concentration of specific light elements versus their depth in materials. The depth is obtained from the energy loss of protons, alphas or recoil atoms in substrate materials. Since the charged particle energy determination using surface barrier detector is used for NDP, the depth resolution is highly dependent on the detectors an d detection instruments. The depth resolutions of a few tens of nm are achieved with available NDP facilities in the world. However, the performance of NDP needs to be improved in order to obtain a few A depth resolutions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-01

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

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

    CERN Document Server

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

    2011-01-01

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

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

    CERN Document Server

    Dubbers, Dirk

    2016-01-01

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

  13. Time-of-Flight Mass Measurements for Nuclear Processes in Neutron Star Crusts

    Science.gov (United States)

    Estradé, A.; Matoš, M.; Schatz, H.; Amthor, A. M.; Bazin, D.; Beard, M.; Becerril, A.; Brown, E. F.; Cyburt, R.; Elliot, T.; Gade, A.; Galaviz, D.; George, S.; Gupta, S. S.; Hix, W. R.; Lau, R.; Lorusso, G.; Möller, P.; Pereira, J.; Portillo, M.; Rogers, A. M.; Shapira, D.; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, M.

    2011-10-01

    We present results from time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory that are relevant for neutron star crust models. The masses of 16 neutron-rich nuclei in the scandium-nickel range were determined simultaneously, with the masses of V61, Cr63, Mn66, and Ni74 measured for the first time with mass excesses of -30.510(890)MeV, -35.280(650)MeV, -36.900(790)MeV, and -49.210(990)MeV, respectively. With these results the locations of the dominant electron capture heat sources in the outer crust of accreting neutron stars that exhibit super bursts are now experimentally constrained. We find the experimental Q value for the Fe66→Mn66 electron capture to be 2.1 MeV (2.6σ) smaller than predicted, resulting in the transition occurring significantly closer to the neutron star surface.

  14. Background optimization for the neutron time-of-flight spectrometer NEAT

    Energy Technology Data Exchange (ETDEWEB)

    Günther, G., E-mail: gerrit.guenther@helmholtz-berlin.de; Russina, M., E-mail: margarita.russina@helmholtz-berlin.de

    2016-08-21

    The neutron time-of-flight spectrometer NEAT at BER II is currently undergoing a major upgrade where an important aspect is the prevention of parasitic scattering to enhance the signal-to-noise ratio. Here, we discuss the impact of shielding to suppress parasitic scattering from two identified sources of background: the sample environment and detector tubes. By means of Monte Carlo simulations and a modification of the analytical model of Copley et al. [Copley and Cook, 1994], the visibility functions of instrument parts are computed for different shielding configurations. According to three selection criteria, namely suppression of background, transmission and detection limit, the parameters of an oscillating radial collimator are optimized for NEAT's default setup. Moreover, different configurations of detector shielding are discussed to prevent cross-talk within the radial detector system.

  15. Understanding inelastically scattered neutrons from water on a time-of-flight small-angle neutron scattering (SANS) instrument

    Energy Technology Data Exchange (ETDEWEB)

    Do, Changwoo, E-mail: doc1@ornl.gov [Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Heller, William T.; Stanley, Christopher [Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Gallmeier, Franz X. [Instrument and Source Design Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Doucet, Mathieu [Neutron Data Analysis and Visualization Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Smith, Gregory S. [Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2014-02-11

    It is generally assumed by most of the small-angle neutron scattering (SANS) user community that a neutron's energy is unchanged during SANS measurements. Here, the scattering from water, specifically light water, was measured on the EQ-SANS instrument, a time-of-flight (TOF) SANS instrument located at the Spallation Neutron Source of Oak Ridge National Laboratory. A significant inelastic process was observed in the TOF spectra of neutrons scattered from water. Analysis of the TOF spectra from the sample showed that the scattered neutrons have energies consistent with room-temperature thermal energies (∼20 meV) regardless of the incident neutron's energy. With the aid of Monte Carlo particle transport simulations, we conclude that the thermalization process within the sample results in faster neutrons that arrive at the detector earlier than expected based on the incident neutron energies. This thermalization process impacts the measured SANS intensities in a manner that will ultimately be sample- and temperature-dependent, necessitating careful processing of the raw data into the SANS cross-section.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

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

    OpenAIRE

    2012-01-01

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

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  20. MONSTER: a time of flight spectrometer for β-delayed neutron emission measurements

    Science.gov (United States)

    Garcia, A. R.; Martínez, T.; Cano-Ott, D.; Castilla, J.; Guerrero, C.; Marín, J.; Martínez, G.; Mendoza, E.; Ovejero, M. C.; Reillo, E. M.; Santos, C.; Tera, F. J.; Villamarín, D.; Nolte, R.; Agramunt, J.; Algora, A.; Tain, J. L.; Banerjee, K.; Bhattacharya, C.; Pentillä, H.; Rinta-Antila, S.; Gorelov, D.

    2012-05-01

    The knowledge of the β-decay properties of nuclei contributes decisively to our understanding of nuclear phenomena: the β-delayed neutron emission of neutron rich nuclei plays an important role in the nucleosynthesis r-process and constitutes a probe for nuclear structure of very neutron rich nuclei providing information about the high energy part of the full beta strength (Sβ) function. In addition, β-delayed neutrons are essential for the control and safety of nuclear reactors. In order to determine the neutron energy spectra and emission probabilities from neutron precursors a MOdular Neutron time-of-flight SpectromeTER (MONSTER) has been proposed for the DESPEC experiment at the future FAIR facility. The design of MONSTER and status of its construction are reported in this work.

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

    Science.gov (United States)

    Goodman, Charles D.

    1979-01-01

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

  2. Time-of-flight calibration of a 6Li glass epithermal neutron detector

    Science.gov (United States)

    Livingston; Saleh; Block; Brand

    2000-10-01

    The curing of Portland cement concrete involves the conversion of water from a free to a bound state. The process can be monitored nondestructively by measuring the shift in the neutron energy spectrum in the epithermal range (0.025-1 eV). A tuned array of 6Li glass detectors has been constructed with varying efficiencies over the epithermal energy range. To determine the efficiency of each detector as a function of neutron energy, it is necessary to calibrate it against a reference neutron spectrum. This was accomplished using a time-of-flight approach with a pulsed neutron beam produced at the Gaerttner LINAC Laboratory at Rensselaer Polytechnic Institute. With a neutron flight path of 25 m it was possible to determine the neutron detector efficiencies to an energy resolution of 11 microeV. The data showed good agreement with the detector design calculations.

  3. Fast neutron measurements at the nELBE time-of-flight facility

    Directory of Open Access Journals (Sweden)

    Junghansa A. R.

    2015-01-01

    Full Text Available The compact neutron-time-of-flight facility nELBE at the superconducting electron accelerator ELBE of Helmholtz-Zentrum Dresden-Rossendorf has been rebuilt. A new enlarged experimental hall with a flight path of up to 10 m is available for neutron time-of-flight experiments in the fast energy range from about 50 keV to 10 MeV. nELBE is intended to deliver nuclear data of fast neutron nuclear interactions e.g. for the transmutation of nuclear waste and improvement of neutron physical simulations of innovative nuclear systems. The experimental programme consists of transmission measurements of neutron total cross sections, elastic and inelastic scattering cross section measurements, and neutron induced fission cross sections. The inelastic scattering to the first few excited states in 56Fe was investigated by measuring the gamma production cross section with an HPGe detector. The neutron induced fission of 242Pu was studied using fast ionisation chambers with large homogeneous actinide deposits.

  4. Geometry Survey of the Time-of-Flight Neutron-Elastic Scattering (Antonella) Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Oshinowo, Babatunde O. [Fermilab; Izraelevitch, Federico [Buenos Aires U.

    2016-10-17

    The Antonella experiment is a measurement of the ionization efficiency of nuclear recoils in silicon at low energies [1]. It is a neutron elastic scattering experiment motivated by the search for dark matter particles. In this experiment, a proton beam hits a lithium target and neutrons are produced. The neutron shower passes through a collimator that produces a neutron beam. The beam illuminates a silicon detector. With a certain probability, a neutron interacts with a silicon nucleus of the detector producing elastic scattering. After the interaction, a fraction of the neutron energy is transferred to the silicon nucleus which acquires kinetic energy and recoils. This kinetic energy is then dissipated in the detector producing ionization and thermal energy. The ionization produced is measured with the silicon detector electronics. On the other hand, the neutron is scattered out of the beam. A neutron-detector array (made of scintillator bars) registers the neutron arrival time and the scattering angle to reconstruct the kinematics of the neutron-nucleus interaction with the time-of-flight technique [2]. In the reconstruction equations, the energy of the nuclear recoil is a function of the scattering angle with respect to the beam direction, the time-of-flight of the neutron and the geometric distances between components of the setup (neutron-production target, silicon detector, scintillator bars). This paper summarizes the survey of the different components of the experiment that made possible the off-line analysis of the collected data. Measurements were made with the API Radian Laser Tracker and I-360 Probe Wireless. The survey was completed at the University of Notre Dame, Indiana, USA in February 2015.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-10-01

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

  8. Invited article: polarization "down under": the polarized time-of-flight neutron reflectometer PLATYPUS.

    Science.gov (United States)

    Saerbeck, T; Klose, F; Le Brun, A P; Füzi, J; Brule, A; Nelson, A; Holt, S A; James, M

    2012-08-01

    This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

  9. Invited Article: Polarization ``Down Under'': The polarized time-of-flight neutron reflectometer PLATYPUS

    Science.gov (United States)

    Saerbeck, T.; Klose, F.; Le Brun, A. P.; Füzi, J.; Brule, A.; Nelson, A.; Holt, S. A.; James, M.

    2012-08-01

    This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

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

    Science.gov (United States)

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

    2012-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Glebov, V. Yu.; Forrest, C.; Knauer, J. P.; Pruyne, A.; Romanofsky, M.; Sangster, T. C.; Shoup, M. J. III; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States); Caggiano, J. A.; Carman, M. L.; Clancy, T. J.; Hatarik, R.; McNaney, J.; Zaitseva, N. P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2012-10-15

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  13. The Design and Optimization Spectrometer with Double Diagnostics of a Neutron Time-of-Flight Scintillators for Neutron on EAST

    Institute of Scientific and Technical Information of China (English)

    张兴; 袁熙; 谢旭飞; 樊铁栓; 陈金象; 李湘庆

    2012-01-01

    Neutron energy spectrometry diagnosis plays an important role in magnetic con- finement fusion. A new neutron time-of-flight (TOF) spectrometer with double scintillators is designed and optimized for the EAST toknmak. A set of optimM parameters is obtained by Monte Carlo simulation, based on the GEANT4 and ROOT codes. The electronic setup of the measurement system is designed. The count rate capability is increased by introducing a flash ADC. The designed spectrometer with high resolution and efficiency is capable of being applied to fusion neutron diagnostics. Applications in mixed-energy and continuous energy neutron fields can also be considered.

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

    Science.gov (United States)

    Cetiner, Mustafa Sacit

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

  15. Fluence measurement at the neutron time of flight experiment at CERN

    CERN Document Server

    Weiss, Christina; Jericha, Erwin

    At the neutron time of flight facility n_TOF at CERN a new spallation target was installed in 2008. In 2008 and 2009 the commissioning of the new target took place. During the summer 2009 a fission chamber of the Physikalisch Technische Bundesanstalt (PTB) Braunschweig was used for the neutron fluence measurement. The evaluation of the data recorded with this detector is the primary topic of this thesis. Additionally a neutron transmission experiment with air has been performed at the TRIGA Mark II reactor of the Atomic Institute of the Austrian Universities (ATI). The experiment was implemented to clarify a question about the scattering cross section of molecular gas which could not be answered clearly via the literature. This problem came up during the evaluations for n_TOF.

  16. Analysis of the neutron time-of-flight spectra from inertial confinement fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hatarik, R., E-mail: hatarik1@llnl.gov; Sayre, D. B.; Caggiano, J. A.; Phillips, T.; Eckart, M. J.; Bond, E. J.; Cerjan, C.; Grim, G. P.; Hartouni, E. P.; Mcnaney, J. M.; Munro, D. H. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Knauer, J. P. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2015-11-14

    Neutron time-of-flight diagnostics have long been used to characterize the neutron spectrum produced by inertial confinement fusion experiments. The primary diagnostic goals are to extract the d + t → n + α (DT) and d + d → n + {sup 3}He (DD) neutron yields and peak widths, and the amount DT scattering relative to its unscattered yield, also known as the down-scatter ratio (DSR). These quantities are used to infer yield weighted plasma conditions, such as ion temperature (T{sub ion}) and cold fuel areal density. We report on novel methodologies used to determine neutron yield, apparent T{sub ion}, and DSR. These methods invoke a single temperature, static fluid model to describe the neutron peaks from DD and DT reactions and a spline description of the DT spectrum to determine the DSR. Both measurements are performed using a forward modeling technique that includes corrections for line-of-sight attenuation and impulse response of the detection system. These methods produce typical uncertainties for DT T{sub ion} of 250 eV, 7% for DSR, and 9% for the DT neutron yield. For the DD values, the uncertainties are 290 eV for T{sub ion} and 10% for the neutron yield.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  18. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures.

    Science.gov (United States)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A; Steuwer, Axel; Kiyanagi, Ryoji; Tremsin, Anton S; Knudsen, Erik B; Shinohara, Takenao; Willendrup, Peter K; da Silva Fanta, Alice Bastos; Iyengar, Srinivasan; Larsen, Peter M; Hanashima, Takayasu; Moyoshi, Taketo; Kadletz, Peter M; Krooß, Philipp; Niendorf, Thomas; Sales, Morten; Schmahl, Wolfgang W; Schmidt, Søren

    2017-08-25

    The physical properties of polycrystalline materials depend on their microstructure, which is the nano- to centimeter scale arrangement of phases and defects in their interior. Such microstructure depends on the shape, crystallographic phase and orientation, and interfacing of the grains constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure. The reconstruction algorithms have been validated by reconstructing two stacked Co-Ni-Ga single crystals, and by comparison with a grain map obtained by post-mortem electron backscatter diffraction (EBSD).

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

    CERN Document Server

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ghetti, R. E-mail: roberta.ghetti@nuclear.lu.se; Colonna, N.; Helgesson, J.; Avdeichikov, V.; Golubev, P.; Jakobsson, B.; Tagliente, G.; Brandenburg, S.; Kravchuk, V.L.; Wilschut, H.W.; Kopecky, S.; Anderson, E.W.; Nadel-Turonski, P.; Westerberg, L.; Bellini, V.; Sperduto, M.L.; Sutera, C

    2004-01-11

    We present the details of an experiment on light particle interferometry. In particular, we focus on a time-of-flight technique which uses a cyclotron RF signal as a start and a liquid scintillator time signal as a stop, to measure neutron energy in the range of E{sub n}{approx}1.8-150 MeV. This dynamic range (up to 300 ns) is much larger than the beam bunch separation (54 ns) of the AGOR cyclotron (KVI). However, the problem of a short burst period is overcome by using the time information obtained from a fast projectile fragment phoswich detector. The complete analysis procedure to extract the final neutron kinetic energy spectra, is discussed.

  1. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures

    DEFF Research Database (Denmark)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A.

    2017-01-01

    constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND......-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure...... enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time...

  2. Diting: A polarized time-of-flight neutron reflectometer at CMRR reactor in China

    Science.gov (United States)

    Li, Xinxi; Huang, Chaoqiang; Wang, Yan; Chen, Bo; Sun, Guang'ai; Liu, Yaoguang; Gong, Jian; Kang, Wu; Liu, Hangang

    2016-11-01

    A new time-of-flight neutron reflectometer with a polarization option is developed and tested at the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, China. Its scattering geometry is horizontal. The constructed neutron reflectometer is a multipurpose instrument that can be used for the characterization of a stratified microstructure and hidden interfaces of solid thin films. Diting is designed for both magnetic and nonmagnetic multi-layer thin films. Spin polarization and analysis are achieved by transmission magnetized supermirrors. The sample unit is equipped with an electromagnet, which can provide a vertical magnetic field range of 0-1.2 tesla. The available neutron beam is a white beam with wavelength range of 0.15-1.25 nm, which can be cut into different wavelength resolution neutron pulses by a four-disk chopper. A two-dimensional position-sensitive detector is employed to count the specular and off-specular reflected neutron beam. A minimum reflectivity of 10-6 is measured on this instrument.

  3. A 3D profile function suitable for integration of neutron time-of-flight single crystal diffraction peaks

    Science.gov (United States)

    Gutmann, Matthias J.

    2017-03-01

    A 3D profile function is presented suitable to integrate reflections arising in time-of-flight (TOF) single crystal neutron diffraction experiments. In order to account for the large asymmetry of the peak shape in the TOF direction, a 3D Gaussian ellipsoid in the pixel (x, z) and time-of-flight coordinates is convoluted with a rising and falling exponential along the time-of-flight direction. An analytic expression is derived, making it suitable for least-squares fitting. The application of this function in detector space or reciprocal space is straightforward.

  4. AMOR – the time-of-flight neutron reflectometer at SINQ/PSI

    Indian Academy of Sciences (India)

    Mukul Gupta; T Gutberlet; J Stahn; P Keller; D Clemens

    2004-07-01

    The apparatus for multioptional reflectometry (AMOR) at SINQ/PSI is a versatile reflectometer operational in the time-of-flight (TOF) mode (in a wavelength range of 0.15 nm > > 1.3 nm) as well as in the monochromatic ( - 2) mode with both polarized and unpolarized neutrons. AMOR is designed to perform reflectometry measurements in horizontal sample-plane geometry which allows studying both solid–liquid and liquid–liquid interfaces. A pulsed cold neutron beam from the end position of the neutron guide is produced by a dual-chopper system (side-by-side) having two windows at 180° and rotatable with a maximum frequency of 200 Hz. In the TOF mode, the chopper frequency, width of the gating window and the chopper–detector distance can be selected independently providing a wide range of -resolution ( / = 1–10%). Remanent FeCoV/Ti : N supermirrors are used as polarizer/analyzer with a polarization efficiency of ∼ 97%. For the monochromatic wavelength mode, a Ni/Ti multilayer is used as a monochromator, giving ∼ 50% reflectivity at a wavelength of 0.47 nm. In the present work, a detailed description of the instrument and setting-up of the polarization option is described. Results from some of the recent studies with polarized neutrons and measurements on liquid surfaces are presented.

  5. Impulse responses of visible phototubes used in National Ignition Facility neutron time of flight diagnostics

    Science.gov (United States)

    Datte, P. S.; Eckart, M.; Moore, A. S.; Thompson, W.; Vergel de Dios, G.

    2016-11-01

    Neutron-induced visible scintillation in neutron time of flight (NToF) diagnostics at the National Ignition Facility (NIF) is measured with 40 mm single stage micro-channel plate photomultipliers and a 40 mm vacuum photodiode, outside the neutron line of sight. In NIF experiments with 14 MeV neutron yields above Y > 10 × 1015 these tubes are configured to deliver of order 1 nC of charge in the nominally 5 ns NToF into a 50 Ω load. We have examined a number of 40 mm tubes manufactured by Photek Ltd. of St. Leonards on Sea, UK, to determine possible changes in the instrument impulse response as a function of signal charge delivered in 1 ns. Precision NToF measurements at approximately 20 m require that we characterize changes in the impulse response moments to <40 ps for the first central moment and ˜2% rms for the square root of the second central moment with ˜500 ps value. Detailed results are presented for three different diode configurations.

  6. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures

    DEFF Research Database (Denmark)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A.

    2017-01-01

    constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND...... enables studies of samples that can be both larger in size and made of heavier elements. Moreover, ToF 3DND facilitates the use of complicated sample environments. The basic ToF 3DND setup, utilizing an imaging detector with high spatial and temporal resolution, can easily be implemented at a time....... The reconstruction algorithms have been validated by reconstructing two stacked Co-Ni-Ga single crystals, and by comparison with a grain map obtained by post-mortem electron backscatter diffraction (EBSD)....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

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

    Science.gov (United States)

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

    2004-10-15

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

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

    Science.gov (United States)

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

    2016-11-01

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

  10. Preliminary energy-filtering neutron imaging with time-of-flight method on PKUNIFTY: A compact accelerator based neutron imaging facility at Peking University

    Science.gov (United States)

    Wang, Hu; Zou, Yubin; Wen, Weiwei; Lu, Yuanrong; Guo, Zhiyu

    2016-07-01

    Peking University Neutron Imaging Facility (PKUNIFTY) works on an accelerator-based neutron source with a repetition period of 10 ms and pulse duration of 0.4 ms, which has a rather low Cd ratio. To improve the effective Cd ratio and thus improve the detection capability of the facility, energy-filtering neutron imaging was realized with the intensified CCD camera and time-of-flight (TOF) method. Time structure of the pulsed neutron source was firstly simulated with Geant4, and the simulation result was evaluated with experiment. Both simulation and experiment results indicated that fast neutrons and epithermal neutrons were concentrated in the first 0.8 ms of each pulse period; meanwhile in the period of 0.8-2.0 ms only thermal neutrons existed. Based on this result, neutron images with and without energy filtering were acquired respectively, and it showed that detection capability of PKUNIFTY was improved with setting the exposure interval as 0.8-2.0 ms, especially for materials with strong moderating capability.

  11. Preliminary energy-filtering neutron imaging with time-of-flight method on PKUNIFTY: A compact accelerator based neutron imaging facility at Peking University

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hu; Zou, Yubin, E-mail: zouyubin@pku.edu.cn; Wen, Weiwei; Lu, Yuanrong; Guo, Zhiyu

    2016-07-01

    Peking University Neutron Imaging Facility (PKUNIFTY) works on an accelerator–based neutron source with a repetition period of 10 ms and pulse duration of 0.4 ms, which has a rather low Cd ratio. To improve the effective Cd ratio and thus improve the detection capability of the facility, energy-filtering neutron imaging was realized with the intensified CCD camera and time-of-flight (TOF) method. Time structure of the pulsed neutron source was firstly simulated with Geant4, and the simulation result was evaluated with experiment. Both simulation and experiment results indicated that fast neutrons and epithermal neutrons were concentrated in the first 0.8 ms of each pulse period; meanwhile in the period of 0.8–2.0 ms only thermal neutrons existed. Based on this result, neutron images with and without energy filtering were acquired respectively, and it showed that detection capability of PKUNIFTY was improved with setting the exposure interval as 0.8–2.0 ms, especially for materials with strong moderating capability.

  12. Data processing workflow for time of flight polarized neutrons inelastic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Savici, Andrei T [ORNL; Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Garlea, Vasile O [ORNL; Winn, Barry L [ORNL

    2017-01-01

    We discuss the data processing workflow for polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. The effects of the focusing Heusler crystal polarizer and the wide-angle supermirror transmission polarization analyzer are added to the data processing flow of the non-polarized case. The implementation is done using the Mantid software package.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  14. Neutron time-of-flight spectrometer based on HIRFL for studies of spallation reactions related to ADS project

    Institute of Scientific and Technical Information of China (English)

    张苏雅拉吐; 罗飞; 陈志强; 韩瑞; 刘星泉; 林炜平; 刘建立; 石福栋; 任培培; 田国玉

    2015-01-01

    A Neutron Time-of-Flight (NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou (HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production double-differential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established. The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented.

  15. Deuterium-tritium neutron yield measurements with the 4.5 m neutron-time-of-flight detectors at NIF.

    Science.gov (United States)

    Moran, M J; Bond, E J; Clancy, T J; Eckart, M J; Khater, H Y; Glebov, V Yu

    2012-10-01

    The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator∕photodetector neutron-time-of-flight (nTOF) detectors for measuring deuterium-deuterium (DD) and DT neutron yields. The detectors provided consistent neutron yield (Y(n)) measurements from below 10(9) (DD) to nearly 10(15) (DT). The detectors initially demonstrated detector-to-detector Y(n) precisions better than 5%, but lacked in situ absolute calibrations. Recent experiments at NIF now have provided in situ DT yield calibration data that establish the absolute sensitivity of the 4.5 m differential tissue harmonic imaging (DTHI) detector with an accuracy of ± 10% and precision of ± 1%. The 4.5 m nTOF calibration measurements also have helped to establish improved detector impulse response functions and data analysis methods, which have contributed to improving the accuracy of the Y(n) measurements. These advances have also helped to extend the usefulness of nTOF measurements of ion temperature and downscattered neutron ratio (neutron yield 10-12 MeV divided by yield 13-15 MeV) with other nTOF detectors.

  16. Deuterium-tritium neutron yield measurements with the 4.5 m neutron-time-of-flight detectors at NIF

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M. J.; Bond, E. J.; Clancy, T. J.; Eckart, M. J.; Khater, H. Y. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Glebov, V. Yu. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2012-10-15

    The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator/photodetector neutron-time-of-flight (nTOF) detectors for measuring deuterium-deuterium (DD) and DT neutron yields. The detectors provided consistent neutron yield (Y{sub n}) measurements from below 10{sup 9} (DD) to nearly 10{sup 15} (DT). The detectors initially demonstrated detector-to-detector Y{sub n} precisions better than 5%, but lacked in situ absolute calibrations. Recent experiments at NIF now have provided in situ DT yield calibration data that establish the absolute sensitivity of the 4.5 m differential tissue harmonic imaging (DTHI) detector with an accuracy of {+-}10% and precision of {+-}1%. The 4.5 m nTOF calibration measurements also have helped to establish improved detector impulse response functions and data analysis methods, which have contributed to improving the accuracy of the Y{sub n} measurements. These advances have also helped to extend the usefulness of nTOF measurements of ion temperature and downscattered neutron ratio (neutron yield 10-12 MeV divided by yield 13-15 MeV) with other nTOF detectors.

  17. A highly efficient neutron time-of-flight detector for inertial confinement fusion experiments

    Science.gov (United States)

    Izumi, N.; Yamaguchi, K.; Yamagajo, T.; Nakano, T.; Kasai, T.; Urano, T.; Azechi, H.; Nakai, S.; Iida, T.

    1999-01-01

    We have developed the highly efficient neutron detector system MANDALA for the inertial-confinement-fusion experiment. The MANDALA system consists of 842 elements plastic scintillation detectors and data acquisition electronics. The detection level is the yield of 1.2×105 for 2.5 MeV and 1×105 for 14.1 MeV neutrons (with 100 detected hits). We have calibrated the intrinsic detection efficiencies of the detector elements using a neutron generator facility. Timing calibration and integrity test of the system were also carried out with a 60Co γ ray source. MANDALA system was applied to the implosion experiments at the GEKKO XII laser facility. The integrity test was carried out by implosion experiments.

  18. The neutron Time-Of-Flight facility, n_TOF, at CERN (I): Technical Description

    CERN Document Server

    n_TOF, Collaboration

    2013-01-01

    The n_TOF facility is a spallation neutron source operating at CERN from 2001. It produces, thanks to the characteristics of the proton driver and of the massive Pb target, a wide energy, very high instantaneous neutron flux, which is employed for neutron-induced reactions measurement. The n TOF facility resumed operation in November 2008, after a 4 years stop due to radioprotection issues connected with the operation of the spallation target. It features a new lead spallation target with a more robust design a more efficient cooling, separate moderator circuit and a target area ventilation system. In this contribution technical details about this facility and its operation will be given, together with future perspective for the performances of the facility.

  19. Application of the Monte Carlo methods and variational procedure for optimizing time-of-flight neutron diffractometer characteristics

    Science.gov (United States)

    Khrushchinsky, A. A.; Kuten, S. A.; Viarenich, K. A.; Speransky, P. A.

    2016-05-01

    Based on variational calculus, a procedure for the optimal approximation of detector surface of the time-of-flight neutron diffractometer has been suggested. The exact solution for a point sample and zero thickness detector has been obtained. Using the shape of the detector surface, an optimized Monte Carlo simulation has been performed for the parameters of the spectrometer depending on the sample size and detector thickness, its azimuthal and Bragg's angular dimensions, and taking into account the neutron absorption in the sample and detector.

  20. Preliminary time-of-flight neutron diffraction study on diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Blum, Marc-Michael [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany); Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, D-80937 Munich (Germany); Koglin, Alexander [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany); Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 (United States); Rüterjans, Heinz [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany); Schoenborn, Benno [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Langan, Paul [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Department of Chemistry, University of Toledo, Toledo, OH 53606 (United States); Chen, Julian C.-H., E-mail: chen@chemie.uni-frankfurt.de [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany)

    2007-01-01

    Diisopropyl fluorophosphatase (DFPase) effectively hydrolyzes a number of organophosphorus nerve agents, including sarin, cyclohexylsarin, soman and tabun. Neutron diffraction data have been collected from DFPase crystals to 2.2 Å resolution in an effort to gain further insight into the mechanism of this enzyme. The enzyme diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris is capable of decontaminating a wide variety of toxic organophosphorus nerve agents. DFPase is structurally related to a number of enzymes, such as the medically important paraoxonase (PON). In order to investigate the reaction mechanism of this phosphotriesterase and to elucidate the protonation state of the active-site residues, large-sized crystals of DFPase have been prepared for neutron diffraction studies. Available H atoms have been exchanged through vapour diffusion against D{sub 2}O-containing mother liquor in the capillary. A neutron data set has been collected to 2.2 Å resolution on a relatively small (0.43 mm{sup 3}) crystal at the spallation source in Los Alamos. The sample size and asymmetric unit requirements for the feasibility of neutron diffraction studies are summarized.

  1. Times of Flight between a Source and a Detector observed from a GPS satelite

    CERN Document Server

    van Elburg, Ronald A J

    2011-01-01

    The Michelson-Morley experiment shows that the experimental outcome of an interference experiment does not depend on the constant velocity of the setup with respect to an inertial frame of reference. From this one can conclude the existence of an invariant velocity of light. However it does not follow from their experiment that a time-of-flight is reference frame independent. In fact the theory of special relativity predicts that the distance between the production location of a particle and the detection location will be changed in all reference frames which have a velocity component parallel to the baseline separating source and detector in a foton time-of-flight experiment. For the OPERA experiment we find that the associated correction is in the order of 32 ns. Because, judging from the information provided, the correction needs to be applied twice in the OPERA experiment the total correction to the final results is in the order of 64 ns. Thus bringing the apparent velocities of neutrino's back to a value...

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

    Science.gov (United States)

    2013-12-01

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

  3. Time-of-flight 3D Neutron Diffraction for Multigrain Crystallography

    DEFF Research Database (Denmark)

    Cereser, Alberto

    detector systems facilitated two versions of ToF 3DND. The first version, restricted to imaging data, enables reconstruction of the position and shape of the individual grains without the use of crystallography. Afterwards, the orientations of the individual grains are indexed. The algorithms for both...... comparison with electron backscatter diffraction (EBSD). In the Iron rod, 107 grains were indexed from the SENJU data. As a comparison, 108 grains were reconstructed from the nearfield data alone. This constitutes roughly 10 times as many grains as previously reported using a continuous neutron source...

  4. The Proton Beams for the New Time-of-Flight Neutron Facility at the CERN-PS

    CERN Document Server

    Cappi, R; Métral, G

    2000-01-01

    The experimental determination of neutron cross sections in fission and capture reactions as a function of the neutron energy is of primary importance in nuclear physics. Recent developments at CERN and elsewhere have shown that many fields of research and development, such as the design of Accelerator-Driven Systems (ADS) for nuclear waste incineration, nuclear astrophysics, fundamental nuclear physics, dosimetry for radiological protection and therapy, would benefit from a better knowledge of neutron cross sections. A neutron facility at the CERN-PS has been proposed with the aim of carrying out a systematic and high resolution study of neutron cross sections through Time-Of-Flight (n-TOF) measurement. The facility requires a high intensity proton beam (about 0.7x1013 particles/bunch) distributed in a short bunch (about 25 ns total length) to produce the neutrons by means of a spallation process in a lead target. To achieve these characteristics, a number of complex beam gymnastics have to be performed. All...

  5. Performance test on PELICAN - a multi-purpose time of flight cold neutron spectrometer

    Science.gov (United States)

    Yu, Dehong; Mole, Richard. A.; Kearley, Gordon J.

    2015-01-01

    Pelican, a direct geometry multi-purpose cold neutron spectrometer has recently been commissioned at the Bragg Institute, ANSTO. The energy resolution and flux at the sample position as a function of neutron wavelength has been evaluated and time focusing at selected energy transfers has also been demonstrated. Several test experiments of quasi-elastic and inelastic neutron scatterings have been performed and these have indicated the realisation of the design specifications and performance of the instrument.

  6. Performance test on PELICAN – a multi-purpose time of flight cold neutron spectrometer

    Directory of Open Access Journals (Sweden)

    Yu Dehong

    2015-01-01

    Full Text Available Pelican, a direct geometry multi-purpose cold neutron spectrometer has recently been commissioned at the Bragg Institute, ANSTO. The energy resolution and flux at the sample position as a function of neutron wavelength has been evaluated and time focusing at selected energy transfers has also been demonstrated. Several test experiments of quasi-elastic and inelastic neutron scatterings have been performed and these have indicated the realisation of the design specifications and performance of the instrument.

  7. Performance test on PELICAN – a multi-purpose time of flight cold neutron spectrometer

    OpenAIRE

    Yu Dehong; Mole Richard. A.; Kearley Gordon J.

    2015-01-01

    Pelican, a direct geometry multi-purpose cold neutron spectrometer has recently been commissioned at the Bragg Institute, ANSTO. The energy resolution and flux at the sample position as a function of neutron wavelength has been evaluated and time focusing at selected energy transfers has also been demonstrated. Several test experiments of quasi-elastic and inelastic neutron scatterings have been performed and these have indicated the realisation of the design specifications and performance of...

  8. Application of a portable 3He-based polarization insert at a time-of-flight neutron reflectometer

    Science.gov (United States)

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

    2017-03-01

    The suitability of a transportable 3He-spin filter as temporary broadband polarizer for a Time-of-Flight neutron reflectometer is demonstrated. A simple two-wavelength method for characterisation of a 3He-spin filter is proposed, which can be applied even if the absolute transmittance of the 3He-spin filter cannot be accurately determined. We demonstrate the data treatment procedure for extracting the spin-up and spin-down neutron reflectivity from measurements obtained with a time dependent 3He polarization. The extraction of a very weak magnetic signal from reflectivity data, measured on the in-situ grown magnetic heterostructure Fe1nm /Cu20nm /Sisubstrate in an externally applied magnetic field of 30 mT is presented and compared to similar measurements on the growth stage Cu20nm /Sisubstrate of the very same sample, which does not yet contain any magnetic material.

  9. A real time scintillating fiber Time of Flight spectrometer for LINAC photoproduced neutrons

    NARCIS (Netherlands)

    Maspero, M; Berra, Alessandro; Conti, Valentina; Giannini, G.; Ostinelli, A.; Prest, M.; Vallazza, E.

    2015-01-01

    The use of high-energy (> 8MeV) LINear ACcelerators (LINACs) for medical cancer treatments causes the photoproduction of secondary neutrons, whose unwanted dose to the patient has to be calculated. The characterization of the neutron spectra is necessary to allow the dosimetric evaluation of the neu

  10. Calculation of the reactor neutron time of flight spectrum by convolution technique

    Institute of Scientific and Technical Information of China (English)

    Cheng Jin-Xing; Ouyang Xiao-Ping; Zheng Yi; Zhang An-Hui; Ouyang Mao-Jie

    2008-01-01

    It is a very complex and tlme-consuming process to simulate the nuclear reactor neutron spectrum from the reactor core to the export channel by applying a Monte Carlo program. This paper presents a new method to calculate the neutron spectrum by using the convolution technique which considers the channel transportation as a linear system and the transportation scattering as the response function. It also applies Monte Carlo Neutron and Photon Transport Code (MCNP) to simulate the response function numerically. With the application of convolution technique to calculate thespectrum distribution from the core to the channel, the process is then much more convenient only with the simple numerical integral numeration. This saves computer time and reduces some trouble in re-writing of the MCNP program.

  11. Design of a north pole Neutron Time-of-Flight (NTOF) system at NIF

    Science.gov (United States)

    Caggiano, J. A.; Barbosa, F.; Clancy, T. J.; Eckart, M. J.; Grim, G.; Hartouni, E. P.; Hatarik, R.; Khater, H.; Lee, A.; Sampson, M.; Sayre, D. B.; Yeamans, C.; Yeoman, M.

    2016-05-01

    A north pole NTOF system for neutron spectroscopy is being implemented at the NIF. The design is centered around a fast scintillator with low mass housing fielded 21.6m from target chamber center at θ=18°,ϕ=304°. The line-of-sight (LOS) features a primary port collimator, two secondary collimators in the intervening concrete floors, and a beam dump with a backscatter shield. Because the detector is being fielded on the roof of the NIF building, diagnostic options such as optical and electrical attenuation are remotely controlled, saving setup time and increasing shot rate. The expected performance of the diagnostic is excellent with high sensitivity to both high-energy reaction-in-flight neutrons as well as lower energy down-scattered neutrons.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    CERN Document Server

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

    2016-01-01

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

  14. Tuning the instrument resolution using chopper and time of flight at the small-angle neutron scattering diffractometer KWS-2.

    Science.gov (United States)

    Radulescu, Aurel; Székely, Noémi Kinga; Polachowski, Stephan; Leyendecker, Marko; Amann, Matthias; Buitenhuis, Johan; Drochner, Matthias; Engels, Ralf; Hanslik, Romuald; Kemmerling, Günter; Lindner, Peter; Papagiannopoulos, Aristeidis; Pipich, Vitaliy; Willner, Lutz; Frielinghaus, Henrich; Richter, Dieter

    2015-12-01

    Following demand from the user community regarding the possibility of improving the experimental resolution, the dedicated high-intensity/extended Q-range SANS diffractometer KWS-2 of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Center in Garching was equipped with a double-disc chopper with a variable opening slit window and time-of-flight (TOF) data acquisition option. The chopper used in concert with a dedicated high-intensity velocity selector enables the tuning at will of the wavelength resolution Δλ/λ within a broad range, from 20% (standard) down to 2%, in a convenient and safe manner following pre-planned or spontaneous decisions during the experiment. The new working mode is described in detail, and its efficiency is demonstrated on several standard samples with known properties and on a completely new crystallizable copolymer system, which were investigated using both the conventional (static) and TOF modes.

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

    Science.gov (United States)

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

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

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

    Science.gov (United States)

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

    2016-10-01

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

  17. Time-of-flight neutron rejection to improve prompt gamma imaging for proton range verification: a simulation study

    Science.gov (United States)

    Biegun, Aleksandra K.; Seravalli, Enrica; Cambraia Lopes, Patrícia; Rinaldi, Ilaria; Pinto, Marco; Oxley, David C.; Dendooven, Peter; Verhaegen, Frank; Parodi, Katia; Crespo, Paulo; Schaart, Dennis R.

    2012-10-01

    Therapeutic proton and heavier ion beams generate prompt gamma photons that may escape from the patient. In principle, this allows for real-time, in situ monitoring of the treatment delivery, in particular, the hadron range within the patient, by imaging the emitted prompt gamma rays. Unfortunately, the neutrons simultaneously created with the prompt photons create a background that may obscure the prompt gamma signal. To enhance the accuracy of proton dose verification by prompt gamma imaging, we therefore propose a time-of-flight (TOF) technique to reject this neutron background, involving a shifting time window to account for the propagation of the protons through the patient. Time-resolved Monte Carlo simulations of the generation and transport of prompt gamma photons and neutrons upon irradiation of a PMMA phantom with 100, 150 and 200 MeV protons were performed using Geant4 (version 9.2.p02) and MCNPX (version 2.7.D). The influence of angular collimation and TOF selection on the prompt gamma and neutron longitudinal profiles is studied. Furthermore, the implications of the proton beam microstructure (characterized by the proton bunch width and repetition period) are investigated. The application of a shifting TOF window having a width of ΔTOFz = 1.0 ns appears to reduce the neutron background by more than 99%. Subsequent application of an energy threshold does not appear to sharpen the distal falloff of the prompt gamma profile but reduces the tail that is observed beyond the proton range. Investigations of the influence of the beam time structure show that TOF rejection of the neutron background is expected to be effective for typical therapeutic proton cyclotrons.

  18. Absolute x-ray and neutron calibration of CVD-diamond-based time-of-flight detectors for the National Ignition Facility

    Science.gov (United States)

    Rosenthal, A.; Kabadi, N. V.; Sio, H.; Rinderknecht, H.; Gatu Johnson, M.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.; Glebov, V.; Forrest, C.; Knauer, J.

    2016-10-01

    The particle-time-of-flight (pTOF) detector at the National Ignition Facility routinely measures proton and neutron nuclear bang-times in inertial confinement fusion (ICF) implosions. The active detector medium in pTOF is a chemical vapor deposition (CVD) diamond biased to 250 - 1500 V. This work discusses an absolute measurement of CVD diamond sensitivity to continuous neutrons and x-rays. Although the impulse response of the detector is regularly measured on a diagnostic timing shot, absolute sensitivity of the detector's response to neutrons and x-rays has not been fully established. X-ray, DD-n, and DT-n sources at the MIT HEDP Accelerator Facility provide continuous sources for testing. CVD diamond detectors are also fielded on OMEGA experiments to measure sensitivity to impulse DT-n. Implications for absolute neutron yield measurements at the NIF using pTOF detectors will be discussed. This work was supported in part by the U.S. DoE and LLNL.

  19. A compact time-of-flight SANS instrument optimised for measurements of small sample volumes at the European Spallation Source

    Science.gov (United States)

    Kynde, Søren; Hewitt Klenø, Kaspar; Nagy, Gergely; Mortensen, Kell; Lefmann, Kim; Kohlbrecher, Joachim; Arleth, Lise

    2014-11-01

    The high flux at European Spallation Source (ESS) will allow for performing experiments with relatively small beam-sizes while maintaining a high intensity of the incoming beam. The pulsed nature of the source makes the facility optimal for time-of-flight small-angle neutron scattering (ToF-SANS). We find that a relatively compact SANS instrument becomes the optimal choice in order to obtain the widest possible q-range in a single setting and the best possible exploitation of the neutrons in each pulse and hence obtaining the highest possible flux at the sample position. The instrument proposed in the present article is optimised for performing fast measurements of small scattering volumes, typically down to 2×2×2 mm3, while covering a broad q-range from about 0.005 1/Å to 0.5 1/Å in a single instrument setting. This q-range corresponds to that available at a typical good BioSAXS instrument and is relevant for a wide set of biomacromolecular samples. A central advantage of covering the whole q-range in a single setting is that each sample has to be loaded only once. This makes it convenient to use the fully automated high-throughput flow-through sample changers commonly applied at modern synchrotron BioSAXS-facilities. The central drawback of choosing a very compact instrument is that the resolution in terms of δλ / λ obtained with the short wavelength neutrons becomes worse than what is usually the standard at state-of-the-art SANS instruments. Our McStas based simulations of the instrument performance for a set of characteristic biomacromolecular samples show that the resulting smearing effects still have relatively minor effects on the obtained data and can be compensated for in the data analysis. However, in cases where a better resolution is required in combination with the large simultaneous q-range characteristic of the instrument, we show that this can be obtained by inserting a set of choppers.

  20. A compact time-of-flight SANS instrument optimised for measurements of small sample volumes at the European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Kynde, Søren, E-mail: kynde@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen (Denmark); Hewitt Klenø, Kaspar [Niels Bohr Institute, University of Copenhagen (Denmark); Nagy, Gergely [SINQ, Paul Scherrer Institute (Switzerland); Mortensen, Kell; Lefmann, Kim [Niels Bohr Institute, University of Copenhagen (Denmark); Kohlbrecher, Joachim, E-mail: Joachim.kohlbrecher@psi.ch [SINQ, Paul Scherrer Institute (Switzerland); Arleth, Lise, E-mail: arleth@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen (Denmark)

    2014-11-11

    The high flux at European Spallation Source (ESS) will allow for performing experiments with relatively small beam-sizes while maintaining a high intensity of the incoming beam. The pulsed nature of the source makes the facility optimal for time-of-flight small-angle neutron scattering (ToF-SANS). We find that a relatively compact SANS instrument becomes the optimal choice in order to obtain the widest possible q-range in a single setting and the best possible exploitation of the neutrons in each pulse and hence obtaining the highest possible flux at the sample position. The instrument proposed in the present article is optimised for performing fast measurements of small scattering volumes, typically down to 2×2×2 mm{sup 3}, while covering a broad q-range from about 0.005 1/Å to 0.5 1/Å in a single instrument setting. This q-range corresponds to that available at a typical good BioSAXS instrument and is relevant for a wide set of biomacromolecular samples. A central advantage of covering the whole q-range in a single setting is that each sample has to be loaded only once. This makes it convenient to use the fully automated high-throughput flow-through sample changers commonly applied at modern synchrotron BioSAXS-facilities. The central drawback of choosing a very compact instrument is that the resolution in terms of δλ/λ obtained with the short wavelength neutrons becomes worse than what is usually the standard at state-of-the-art SANS instruments. Our McStas based simulations of the instrument performance for a set of characteristic biomacromolecular samples show that the resulting smearing effects still have relatively minor effects on the obtained data and can be compensated for in the data analysis. However, in cases where a better resolution is required in combination with the large simultaneous q-range characteristic of the instrument, we show that this can be obtained by inserting a set of choppers.

  1. A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors.

    Science.gov (United States)

    Waugh, C J; Rosenberg, M J; Zylstra, A B; Frenje, J A; Séguin, F H; Petrasso, R D; Glebov, V Yu; Sangster, T C; Stoeckl, C

    2015-05-01

    Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition, comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.

  2. Crystal structures of deuterated sodium molybdate dihydrate and sodium tungstate dihydrate from time-of-flight neutron powder diffraction.

    Science.gov (United States)

    Fortes, A Dominic

    2015-07-01

    Time-of-flight neutron powder diffraction data have been measured from ∼90 mol% deuterated isotopologues of Na2MoO4·2H2O and Na2WO4·2H2O at 295 K to a resolution of sin (θ)/λ = 0.77 Å(-1). The use of neutrons has allowed refinement of structural parameters with a precision that varies by a factor of two from the heaviest to the lightest atoms; this contrasts with the X-ray based refinements where precision may be > 20× poorer for O atoms in the presence of atoms such as Mo and W. The accuracy and precision of inter-atomic distances and angles are in excellent agreement with recent X-ray single-crystal structure refinements whilst also completing our view of the hydrogen-bond geometry to the same degree of statistical certainty. The two structures are isotypic, space-group Pbca, with all atoms occupying general positions, being comprised of edge- and corner-sharing NaO5 and NaO6 polyhedra that form layers parallel with (010) inter-leaved with planes of XO4 (X = Mo, W) tetra-hedra that are linked by chains of water mol-ecules along [100] and [001]. The complete structure is identical with the previously described molybdate [Capitelli et al. (2006 ▸). Asian J. Chem. 18, 2856-2860] but shows that the purported three-centred inter-action involving one of the water mol-ecules in the tungstate [Farrugia (2007 ▸). Acta Cryst. E63, i142] is in fact an ordinary two-centred 'linear' hydrogen bond.

  3. Neutron-emission measurements at a white neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory

    2010-01-01

    Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

  4. Neutron capture cross section measurement of $^{151}Sm$ at the CERN neutron Time of Flight Facility (nTOF)

    CERN Document Server

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

    2004-01-01

    The measurement of **1**5**1Sm(n, gamma)**1**5**2Sm (samarium) cross section showed improved performance of the new spallation neutron facility. It covered a wide energy range with good resolution, high neutron flux, low backgrounds and a favourable duty factor. The samarium cross section was found to be of great importance for characterizing neutron capture nucleosynthesis in asymptotic giant stars. The combination of these features provided a promising basis for a broad experimental program directed towards application in astrophysics and advanced nuclear technologies. (Edited abstract)

  5. LSO background radiation as a transmission source using time of flight.

    Science.gov (United States)

    Rothfuss, Harold; Panin, Vladimir; Moor, Andrew; Young, John; Hong, Inki; Michel, Christian; Hamill, James; Casey, Michael

    2014-09-21

    LSO scintillators (Lu2Sio5:Ce) have a background radiation which originates from the isotope Lu-176 that is present in natural occurring lutetium. The decay that occurs in this isotope is a beta decay that is in coincidence with cascade gamma emissions with energies of 307,202 and 88 keV. The coincidental nature of the beta decay with the gamma emissions allow for separation of emission data originating from a positron annihilation event from transmission type data from the Lu-176 beta decay. By using the time of flight information, and information of the chord length between two LSO pixels in coincidence as a result of a beta emission and emitted gamma, a second time window can be set to observe transmission events simultaneously to emission events. Using the time when the PET scanner is not actively acquiring positron emission data, a continuous blank can be acquired and used to reconstruct a transmission image. With this blank and the measured transmission data, a transmission image can be reconstructed. This reconstructed transmission image can be used to perform emission data corrections such as attenuation correction and scatter corrections or starting images for algorithms that estimate emission and attenuation simultaneously. It is observed that the flux of the background activity is high enough to create useful transmission images with an acquisition time of 10 min.

  6. Time-of-flight mass measurements of neutron-rich chromium isotopes up to N = 40 and implications for the accreted neutron star crust

    CERN Document Server

    Meisel, Z; Ahn, S; Bazin, D; Brown, B A; Browne, J; Carpino, J F; Chung, H; Cyburt, R H; Estradé, A; Famiano, M; Gade, A; Langer, C; Matoš, M; Mittig, W; Montes, F; Morrissey, D J; Pereira, J; Schatz, H; Schatz, J; Scott, M; Shapira, D; Sieja, K; Smith, K; Stevens, J; Tan, W; Tarasov, O; Towers, S; Wimmer, K; Winkelbauer, J R; Yurkon, J; Zegers, R G T

    2016-01-01

    We present the mass excesses of 59-64Cr, obtained from recent time-of-flight nuclear mass measurements at the National Superconducting Cyclotron Laboratory at Michigan State University. The mass of 64Cr is determined for the first time, with an atomic mass excess of -33.48(44) MeV. We find a significantly different two-neutron separation energy S2n trend for neutron-rich isotopes of chromium, removing the previously observed enhancement in binding at N=38. Additionally, we extend the S2n trend for chromium to N=40, revealing behavior consistent with the previously identified island of inversion in this region. We compare our results to state-of-the-art shell-model calculations performed with a modified Lenzi-Nowacki-Poves-Sieja interaction in the fp shell, including the g9/2 and d5/2 orbits for the neutron valence space. We employ our result for the mass of 64Cr in accreted neutron star crust network calculations and find a reduction in the strength and depth of electron-capture heating from the A=64 isobaric...

  7. Considerations about Chopper Configuration at a time-of-flight SANS Instrument at a Spallation Source

    CERN Document Server

    Jaksch, Sebastian

    2016-01-01

    In any neutron scattering experiment the measurement of the position of the scattered neutrons and their respective velocities is necessary. In order to do so, a position sensitive detector as well as a way to determine the velocities is needed. Measuring the velocities can either be done by using only a single wavelength and therefore velocity or by creating pulses, where the start and end time of each pulse is known and registering the time of arrival at the detector, which is the case we want to consider here. This pulse shaping process in neutron scattering instruments is usually done by using a configuration of several choppers. This set of choppers is then used to define both the beginning and the end of the pulse. Additionally there is of course also a selection in phase space determining the final resolution that can be achieved by the instrument. Taking into account the special requirements of a specific instrument, here a small-angle neutron scattering instrument, creates an additional set of restri...

  8. A novel method for modeling the neutron time of flight (nTOF) detector response in current mode to inertial confinement fusion experiments.

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Alan J. [University of New Mexico, Albuquerque, NM; Cooper, Gary Wayne [University of New Mexico, Albuquerque, NM; Ruiz, Carlos L.; Chandler, Gordon Andrew; Fehl, David Lee; Hahn, Kelly Denise; Leeper, Ramon Joe; Smelser, Ruth Marie; Torres, Jose A.

    2013-09-01

    There are several machines in this country that produce short bursts of neutrons for various applications. A few examples are the Zmachine, operated by Sandia National Laboratories in Albuquerque, NM; the OMEGA Laser Facility at the University of Rochester in Rochester, NY; and the National Ignition Facility (NIF) operated by the Department of Energy at Lawrence Livermore National Laboratory in Livermore, California. They all incorporate neutron time of flight (nTOF) detectors which measure neutron yield, and the shapes of the waveforms from these detectors contain germane information about the plasma conditions that produce the neutrons. However, the signals can also be %E2%80%9Cclouded%E2%80%9D by a certain fraction of neutrons that scatter off structural components and also arrive at the detectors, thereby making analysis of the plasma conditions more difficult. These detectors operate in current mode - i.e., they have no discrimination, and all the photomultiplier anode charges are integrated rather than counted individually as they are in single event counting. Up to now, there has not been a method for modeling an nTOF detector operating in current mode. MCNPPoliMiwas developed in 2002 to simulate neutron and gammaray detection in a plastic scintillator, which produces a collision data output table about each neutron and photon interaction occurring within the scintillator; however, the postprocessing code which accompanies MCNPPoliMi assumes a detector operating in singleevent counting mode and not current mode. Therefore, the idea for this work had been born: could a new postprocessing code be written to simulate an nTOF detector operating in current mode? And if so, could this process be used to address such issues as the impact of neutron scattering on the primary signal? Also, could it possibly even identify sources of scattering (i.e., structural materials) that

  9. Determination of stimulants using gas chromatography/high-resolution time-of-flight mass spectrometry and a soft ionization source.

    Science.gov (United States)

    Lopez-Avila, Viorica; Cooley, James; Urdahl, Randall; Thevis, Mario

    2012-12-15

    The aim of this study was to investigate the mass spectral fragmentation of a small set of stimulants in a high-resolution time-of-flight mass spectrometer equipped with a soft ionization source using vacuum ultraviolet (VUV) photons emitted from different plasma gases. It was postulated that the use of a plasma gas such as Xe, which emits photons at a lower energy than Kr or Ar, would lead to softer ionization of the test compounds, and thus to less fragmentation. A set of nine stimulants: cocaine, codeine, nicotine, methadone, phenmetrazine, pentylenetetrazole, niketamide, fencamfamine, and caffeine, was analyzed by gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) in positive ion mode with this soft ionization source, using either Xe, Kr, or Ar as plasma gases. Working solutions of the test compounds at 0.1 to 100 ng/μL were used to establish instrument sensitivity and linearity. All test compounds, except methadone and pentylenetetrazole, exhibited strong molecular ions and no fragmentation with Xe-microplasma photoionization (MPPI). Methadone exhibited significant fragmentation not only with Xe, but also with Kr and Ar, and pentylenetetrazole could not be ionized with Xe, probably because its ionization energy is above 8.44 eV. The Kr- and Ar-MPPI mass spectra of the test compounds showed that the relative intensity of the molecular ion decreased as the photon energy increased. When coupled to a TOF mass spectrometer this soft ionization source has demonstrated signal-to-noise (S/N) ratios from 7 to 730 at 100 pg per injection (depending on the compound), and a dynamic range of three orders of magnitude (100 pg to 100 ng) for some of the test compounds. Copyright © 2012 John Wiley & Sons, Ltd.

  10. Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility

    Science.gov (United States)

    Sayre, D. B.; Barbosa, F.; Caggiano, J. A.; DiPuccio, V. N.; Eckart, M. J.; Grim, G. P.; Hartouni, E. P.; Hatarik, R.; Weber, F. A.

    2016-11-01

    Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures' image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures' edges. The fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at the National Ignition Facility.

  11. Neutron energy and time-of-flight spectra behind the lateral shield of a high energy electron accelerator beam dump 2, Monte Carlo simulations

    CERN Document Server

    Roesler, Stefan; Rokni, Sayed H; Taniguchi, Shingo

    2003-01-01

    Energy spectra of high-energy neutrons and neutron time-of-flight spectra were calculated for the setup of experiment T-454 performed with a NE213 liquid scintillator at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were created by the interaction a 28.7 GeV electron beam in the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shielding. In order to determine the attenuation length of high-energy neutrons additional concrete shielding of various thicknesses was placed outside the existing shielding. The calculations were performed using the FLUKA interaction and transport code. The energy and time-of-flight spectra were recorded for the location of the detector allowing a detailed comparison with the experimental data. A generally good description of the data is achieved adding confidence to the use of FLUKA for the design of shielding for high-energy electron accelerators. (5 refs).

  12. Neutron energy and time-of-flight spectra behind the lateral shield of a high-energy electron accelerator beam dump. Part 2. Monte Carlo simulations

    CERN Document Server

    Roesler, S; Rokni, S H; Taniguchi, S

    2003-01-01

    Energy spectra of high-energy neutrons and neutron time-of-flight spectra were calculated for the setup of experiment T-454 performed with a NE213 liquid scintillator at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were created by the interaction a 28.7 GeV electron beam in the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shielding. In order to determine the attenuation length of high-energy neutrons additional concrete shielding of various thicknesses was placed outside the existing shielding. The calculations were performed using the FLUKA interaction and transport code. The energy and time-of-flight spectra were recorded for the location of the detector allowing a detailed comparison with the experimental data. A generally good description of the data is achieved adding confidence to the use of FLUKA for the design of shielding for high-energy electron accelerators.

  13. Advances in surface ion suppression from RILIS: Towards the Time-of-Flight Laser Ion Source (ToF-LIS)

    CERN Document Server

    Rothe, S; Crepieux, B; Day Goodacre, T; Fedosseev, V N; Giles, T; Marsh, B A; Ramos, J P; Rossel, R E

    2016-01-01

    We present results from the development towards the Time-of-Flight Laser Ion Source (ToF-LIS) aiming for the suppression of isobaric contaminants through fast beam gating. The capability to characterize high resistance ion sources has been successfully demonstrated. A ninefold selectivity gain has been achieved through suppression of surface ionized potassium, while maintaining >90% transmission for laser-ionized gallium using a thin wall graphite ionizer cavity combined with a fast beam gate. Initial results from the investigation of glassy carbon as a potential hot cavity ion source are presented. Power-cycle tests of a newly designed mount for fragile ion source cavities indicates its capability to survive the thermal stress expected during operation in an ISOLDE target unit. Finally, we introduce fast ion beam switching at a rate of 10 kHz using the ISOLDE ion beam switchyard as a new concept for ion beam distribution and conclude by highlighting the potential applications of this ion beam multiplexing te...

  14. Advances in surface ion suppression from RILIS: Towards the Time-of-Flight Laser Ion Source (ToF-LIS)

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, S., E-mail: sebastian.rothe@cern.ch [CERN, Geneva (Switzerland); Catherall, R.; Crepieux, B. [CERN, Geneva (Switzerland); Day Goodacre, T. [CERN, Geneva (Switzerland); School of Physics and Astronomy, The University of Manchester, Manchester (United Kingdom); Fedosseev, V.N.; Giles, T.; Marsh, B.A. [CERN, Geneva (Switzerland); Ramos, J.P. [CERN, Geneva (Switzerland); Laboratory of Powder Technology, EPFL, Lausanne (Switzerland); Rossel, R.E. [CERN, Geneva (Switzerland); Institut für Physik, Johannes Gutenberg-Universität, Mainz (Germany); Faculty of Design, Computer Science and Media, Hochschule RheinMain, Wiesbaden (Germany)

    2016-06-01

    We present results from the development towards the Time-of-Flight Laser Ion Source (ToF-LIS) aiming for the suppression of isobaric contaminants through fast beam gating. The capability to characterize high resistance ion sources has been successfully demonstrated. A ninefold selectivity gain has been achieved through suppression of surface ionized potassium, while maintaining >90% transmission for laser-ionized gallium using a thin wall graphite ionizer cavity combined with a fast beam gate. Initial results from the investigation of glassy carbon as a potential hot cavity ion source are presented. Power-cycle tests of a newly designed mount for fragile ion source cavities indicates its capability to survive the thermal stress expected during operation in an ISOLDE target unit. Finally, we introduce fast ion beam switching at a rate of 10 kHz using the ISOLDE ion beam switchyard as a new concept for ion beam distribution and conclude by highlighting the potential applications of this ion beam multiplexing technique.

  15. Quasi-trapping chemical ionization source based on a commercial VUV lamp for time-of-flight mass spectrometry.

    Science.gov (United States)

    Chen, Ping; Hou, Keyong; Hua, Lei; Xie, Yuanyuan; Zhao, Wuduo; Chen, Wendong; Chen, Chuang; Li, Haiyang

    2014-02-04

    The application of VUV lamp-based single photon ionization (SPI) was limited due to low photon energy and poor photon flux density. In this work, we designed a quasi-trapping chemical ionization (QT-CI) source with a commercial VUV 10.6 eV krypton lamp for time-of-flight mass spectrometry. The three electrode configuration ion source with RF voltage on the second electrode constitutes a quasi-trapping region, which has two features: accelerating the photoelectrons originated from the photoelectric effect with VUV light to trigger the chemical ionization through ion-molecule reaction and increasing the collisions between reactant ion O2(+) and analyte molecules to enhance the efficiency of chemical ionization. Compared to single SPI based on VUV krypton lamp, the QT-CI ion source not only apparently improved the sensitivity (e.g., 12-118 fold enhancement were achieved for 13 molecules, including aromatic hydrocarbon, chlorinated hydrocarbon, hydrogen sulfide, etc.) but also extended the range of ionizable molecules with ionization potential (IP) higher than 10.6 eV, such as propane, dichloroethane, and trichloromethane.

  16. Deuterated-xylene (xylene-d{sub 10}; EJ301D): A new, improved deuterated liquid scintillator for neutron energy measurements without time-of-flight

    Energy Technology Data Exchange (ETDEWEB)

    Becchetti, F.D.; Raymond, R.S.; Torres-Isea, R.O. [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Di Fulvio, A.; Clarke, S.D.; Pozzi, S.A. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Febbraro, M. [Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States)

    2016-06-01

    In conjunction with Eljen Technology, Inc. (Sweetwater,TX) we have designed, constructed, and evaluated a 3 in. ×3 in. deuterated-xylene organic liquid scintillator (C{sub 8}D{sub 10}; EJ301D) as a fast neutron detector. Similar to deuterated benzene (C{sub 6}D{sub 6}; NE230, BC537, and EJ315) this scintillator can provide good pulse-shape discrimination between neutrons and gamma rays, has good timing characteristics, and can provide a light spectrum with peaks corresponding to discrete neutron energy groups up to ca. 20 MeV. Unlike benzene-based detectors, deuterated xylene is less volatile, less toxic, is not known to be carcinogenic, has a higher flashpoint, and hence is much safer for many applications. In addition EJ301D can provide slightly more light output and better PSD than deuterated-benzene scintillators. We show that, as with deuterated-benzene scintillators, the light-response spectra can be unfolded to provide useable neutron energy spectra without need for time-of-flight (ToF). An array of these detectors arranged at many angles close to a reaction target can be much more effective (×10 to ×100 or more) than an array of long-path ToF detectors which must utilize a narrowly-bunched and pulse-selected beam. As we demonstrate using a small Van de Graaff accelerator, measurements can thus be performed when a bunched and pulse-selected beam (as needed for time-of-flight) is not available.

  17. Novel time-of-flight fiber dispersion measurement technique using supercontinuum light sources and acousto-optical tunable filters.

    Science.gov (United States)

    Blume, Niels Göran; Wagner, Steven

    2015-07-20

    Long-distance fiber links require precise knowledge of fiber dispersion characteristics. Similar dispersion characteristics are necessary for supercontinuum broadband laser absorption spectroscopy (SCLAS) to allow proper data evaluation and species concentration determination, as well as numerous other applications. In this work, a time-of-flight approach to measuring the dispersion characteristic of fibers with supercontinuum laser light sources (SCLs) and acousto-optical tunable filters (AOTFs) is presented. Broadband emission of the SCL is filtered with a narrowband AOTF and dispersed in time by the fiber under test. By using the wavelength-specific delay, the dispersion characteristic can be calculated. The technique is especially suited for longer fibers and was verified against a state-of-the-art phase-shift-based dispersion measurement system. Advantages of the new approach include solely utilizing SCLAS system components, as well as a high level of automation and wide spectral coverage, ranging from 1100 to 1700 nm in a single measurement setup.

  18. The high intensity neutron source FRANZ

    CERN Document Server

    Lederer, Claudia

    2014-01-01

    The Frankfurt neutron source of Stern Gerlach Zentrum FRANZ is currently under construction at the University of Frankfurt. At FRANZ, a high intensity neutron beam in the keV energy region will be produced by bombarding a $^7$Li target with a proton beam of several mA. These unprecedented high neutron fluxes will allow a number of neutron induced cross section measurements for the first time. Measurements can be performed by the time-of-flight and by the activation technique.

  19. Non-destructive magneto-strain analysis of YB2Cu3Oy superconducting magnets using neutron diffraction in the time-of-flight mode

    Science.gov (United States)

    Tomita, M.; Muralidhar, M.; Suzuki, K.; Ishihara, A.; Fukumoto, Y.; Osamura, K.; Machiya, S.; Harjo, S.

    2012-09-01

    In general, neutron diffraction allows a non-destructive investigation of bulk samples. In this study, a magneto-strain analysis of the trapped field in YB2Cu3Oy "YBCO" superconducting bulks was carried out at 45 K using neutron diffraction time-of-flight (TOF) method. The TAKUMI TOF neutron diffractometer offers unique advantages, including accommodation of large objectives, control of the experimental set-up using a 4-axial goniometer (XYZθ), and a positional resolution of 0.01 mm allowing an accurate sample positioning. As a result, the lattice strain in the YB2Cu3Oy material could be estimated in both radial and hoop directions by estimating the difference of plane spacing with/without the trapped magnetic field. The results indicate that the samples with a low trapped field values have smaller magnetic strain than those with a high trapped field. Further, the strain in the hoop direction is higher than that in the radial direction. The present results indicate that neutron diffraction measurements are an effective method for evaluating the bulk residual strains in a non-destructive manner.

  20. The Structure of Ta3N5 at 16K by Time-of-Flight Neutron Diffraction

    Science.gov (United States)

    1991-05-30

    Moureu & Hamblet , 1937) . It is reported to have the pseudobrookite (Fe2TiO5) structure. Although the unit cell was originally given as metrically...Neutron Scattering Center, Los Alamos, NM 87545. Moureu, H. & Hamblet , C. H. (1937) . J. Amer. Chem. Soc. 59, 33-40. Mueller, M. H. (1977) . Scripta

  1. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  2. Applications of the associated-particle neutron-time-of-flight interrogation technique - From sheep to unexploded ordnance

    Science.gov (United States)

    Mitra, S.

    2013-04-01

    The associated-particle technique (APT) will be presented for some diverse applications that include on the one hand, analyzing the body composition of live sheep and on the other, identifying the fillers of unexploded ordnance (UXO). What began with proof-of-concept studies using a large laboratory based 14 MeV neutron generator of the "associated-particle" type, soon became possible for the first time to measure total body protein, fat and water simultaneously in live sheep using a compact field deployable associated-particle sealed-tube neutron generator (APSTNG). This non-invasive technique offered the animal physiologist a tool to monitor the growth of an animal in response to new genetic, nutritional and pharmacologic methods for livestock improvement. While measurement of carbon (C), nitrogen (N) and oxygen (O) determined protein, fat and water because of the fixed stoichiometric proportions of these elements in these body components, the unique C/N and C/O ratios of high explosives revealed their identity in UXO. The algorithm that was developed and implemented to extract C, N and O counts from an APT generated gamma-ray spectrum will be presented together with the UXO investigations that involved preliminary proofof-concept studies and modeling with Monte Carlo produced synthetic spectra of 57-155 mm projectiles.

  3. New time-of-flight data for the neutron capture cross-section of {sup 63}Cu

    Energy Technology Data Exchange (ETDEWEB)

    Weigand, M.; Reifarth, R. [Goethe Universitaet, Frankfurt (Germany); Bredeweg, T.A.; Couture, A.; Jandel, M.; O' Donnell, J.M.; Ullmann, J.L. [LANL, Los Alamos (United States)

    2014-07-01

    One of the important questions in nuclear astrophysics is how the observed abundances of elements came to be. Nearly all of the elements beyond the iron peak are either formed by the s- or the r-process in almost equal shares. The precise s-process path depends on stellar parameters like temperature and neutron density, and on nuclear parameters like half-lifes and neutron capture cross-sections (NCS). Thus, there is a big need for experimental data on the involved reactions to calculate their stellar rates to understand s-process nucleosynthesis. The NCS of the copper isotopes influences the isotopic ratios of Zn. Former experiments concerning the NCS of {sup 63}Cu showed large discrepancies. In order to determine the {sup 63}Cu(n,γ) cross-section in the astrophysical energy region, an experiment has been performed using the calorimetric 4π-BaF{sub 2} array DANCE at the Los Alamos National Lab (LANL). The results of the experiment will be presented.

  4. Prototyping and tests for an MRPC-based time-of-flight detector for 1 GeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Yakorev, D. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Aumann, T. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt (Germany); Bemmerer, D., E-mail: d.bemmerer@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Boretzky, K. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Caesar, C. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt (Germany); Ciobanu, M. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Cowan, T.; Elekes, Z. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Elvers, M. [Universitaet zu Koeln (Germany); Gonzalez Diaz, D. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt (Germany); Tsinghua University, Beijing (China); Hannaske, R. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Hehner, J.; Heil, M. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Kempe, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Maroussov, V. [Universitaet zu Koeln (Germany); Nusair, O. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Al Balqa' Applied University, Salt (Jordan); Simon, H. [GSI Helmholtz zentrum fuer Schwerionenforschung, Darmstadt (Germany); Sobiella, M.; Stach, D.; Wagner, A. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); and others

    2011-10-21

    The NeuLAND detector at the R{sup 3}B experiment at the future FAIR facility in Darmstadt aims to detect fast neutrons (0.2-1.0 GeV) with high time and spatial resolutions ({sigma}{sub t}<100ps,{sigma}{sub x,y,z}<1cm). This task can be performed either with a scintillator or based on the multigap resistive plate chamber (MRPC) technology. Here, prototyping and test for an MRPC-based solution are discussed. In order to reach 90% detection efficiency, the final detector must consist of 50 consecutive MRPC stacks. Each stack contains a 4 mm thick anode made of iron converter material, with an additional 4 mm of converter material between two stacks. The secondary charged particles stemming from hadronic interactions of the high energetic neutrons in the converter will be detected in the MRPCs. As part of the ongoing development effort, a number of prototypes for this detector have been developed and built. They have been tested in experiments with a single-electron beam with picosecond resolution at the superconducting linac ELBE (Dresden, Germany). The results of the tests are presented here, and an outlook is given.

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

    Science.gov (United States)

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

    2014-01-28

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

  6. Effect of high current electron beam in a 30 MeV radio frequency linac for neutron-time-of-flight applications

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, B., E-mail: biswaranjan.nayak1@gmail.com; Acharya, S.; Rajawat, R. K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); DasGupta, K. [Accelerator and Pulsed Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Beam Technology Development Group, BARC, Mumbai 400085 (India)

    2016-01-15

    A high power pulsed radio frequency electron linac is designed by BARC, India to accelerate 30 MeV, 10 A, 10 ns beam for neutron-time-of-flight applications. It will be used as a neutron generator and will produce ∼10{sup 12}–10{sup 13} n/s. It is essential to reduce the beam instability caused by space charge effect and the beam cavity interaction. In this paper, the wakefield losses in the accelerating section due to bunch of RMS (Root mean square) length 2 mm (at the gun exit) is analysed. Loss and kick factors are numerically calculated using CST wakefield solver. Both the longitudinal and transverse wake potentials are incorporated in beam dynamics code ELEGANT to find the transverse emittance growth of the beam propagating through the linac. Beam loading effect is examined by means of numerical computation carried out in ASTRA code. Beam break up start current has been estimated at the end of the linac which arises due to deflecting modes excited by the high current beam. At the end, transverse beam dynamics of such high current beam has been analysed.

  7. Glycine zinc sulfate pentahydrate: redetermination at 10 K from time-of-flight neutron Laue diffraction

    Directory of Open Access Journals (Sweden)

    A. Dominic Fortes

    2016-10-01

    Full Text Available Single crystals of glycine zinc sulfate pentahydrate [systematic name: hexaaquazinc tetraaquadiglycinezinc bis(sulfate], [Zn(H2O6][Zn(C2H5NO22(H2O4](SO42, have been grown by isothermal evaporation from aqueous solution at room temperature and characterized by single-crystal neutron diffraction. The unit cell contains two unique ZnO6 octahedra on sites of symmetry -1 and two SO4 tetrahedra with site symmetry 1; the octahedra comprise one [tetraaqua-diglycine zinc]2+ ion (centred on one Zn atom and one [hexaaquazinc]2+ ion (centred on the other Zn atom; the glycine zwitterion, NH3+CH2COO−, adopts a monodentate coordination to the first Zn atom. All other atoms sit on general positions of site symmetry 1. Glycine forms centrosymmetric closed cyclic dimers due to N—H...O hydrogen bonds between the amine and carboxylate groups of adjacent zwitterions and exhibits torsion angles varying from ideal planarity by no more than 1.2°, the smallest values for any known glycine zwitterion not otherwise constrained by a mirror plane. This work confirms the H-atom locations estimated in three earlier single-crystal X-ray diffraction studies with the addition of independently refined fractional coordinates and Uij parameters, which provide accurate internuclear X—H (X = N, O bond lengths and consequently a more accurate and precise depiction of the hydrogen-bond framework.

  8. Validation of Direct Analysis Real Time source/Time-of-Flight Mass Spectrometry for organophosphate quantitation on wafer surface.

    Science.gov (United States)

    Hayeck, Nathalie; Ravier, Sylvain; Gemayel, Rachel; Gligorovski, Sasho; Poulet, Irène; Maalouly, Jacqueline; Wortham, Henri

    2015-11-01

    Microelectronic wafers are exposed to airborne molecular contamination (AMC) during the fabrication process of microelectronic components. The organophosphate compounds belonging to the dopant group are one of the most harmful groups. Once adsorbed on the wafer surface these compounds hardly desorb and could diffuse in the bulk of the wafer and invert the wafer from p-type to n-type. The presence of these compounds on wafer surface could have electrical effect on the microelectronic components. For these reasons, it is of importance to control the amount of these compounds on the surface of the wafer. As a result, a fast quantitative and qualitative analytical method, nondestructive for the wafers, is needed to be able to adjust the process and avoid the loss of an important quantity of processed wafers due to the contamination by organophosphate compounds. Here we developed and validated an analytical method for the determination of organic compounds adsorbed on the surface of microelectronic wafers using the Direct Analysis in Real Time-Time of Flight-Mass Spectrometry (DART-ToF-MS) system. Specifically, the developed methodology concerns the organophosphate group.

  9. Tagging fast neutrons from a 252Cf fission-fragment source

    CERN Document Server

    Scherzinger, Julius; Annand, John; Fissum, Kevin; Hall-Wilton, Richard; Mauritzson, Nicholai; Messi, Francesco; Perrey, Hanno; Rofors, Emil

    2016-01-01

    Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a 252Cf source. Fission fragments detected in a gaseous 4He scintillator detector supply the tag. Neutrons are detected in a NE-213 liquid-scintillator detector. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations.

  10. Use of the generalized spherical harmonic model for describing crystallographic texture in polycrystalline NiTi shape-memory alloy with time-of-flight neutron powder diffraction data

    CERN Document Server

    Sitepu, H; Dreele, R B V

    2002-01-01

    We present a feasibility study to extract quantitative texture and precise crystal structure information of polycrystalline monoclinic NiTi shape-memory alloys from a simultaneous refinement of 52 time-of-flight neutron-diffraction patterns taken in 13 orientations in the diffractometer. The multiple-data-set capabilities and the generalized spherical harmonic texture model of the GSAS program system were employed. (orig.)

  11. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  12. Characterization of a compact filament-driven multicusp ion source for low energy time-of-flight Rutherford backscattering spectrometry application

    Science.gov (United States)

    Dangtip, S.; Junphong, P.; Ano, V.; Lekprasert, B.; Suwannakachorn, D.; Thongnopparat, N.; Vilaithong, T.

    2004-05-01

    Because of the limited pulse height energy resolution of a detector, conventional Rutherford backscattering spectrometry (RBS) requires an energy of the incident α particle to be in the MeV region. At Chiang Mai University we have researched the possibility of utilizing a 280 keV nanosecond pulse of helium ions for RBS applications. We have chosen a compact filament-driven multicusp ion source of 2.6 cm in diameter and 8 cm in length being investigated for the time-of-flight RBS applications. In this article, we present the general ion source performance using helium, nitrogen, and argon for generating the discharge plasma. The general ion source characteristics have been measured and analyzed. The measurements also include the extractable ion current and the ion beam emittance. We have performed beam extraction calculations with a computer simulation code KOBRA. Results of the measurements and calculations will be presented and discussed.

  13. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  14. Development of a novel low-pressure detector with high position and time-of-flight resolution for thermal neutron detection

    CERN Document Server

    Schulz, C

    2000-01-01

    The pulsed high-flux neutron source ESS, in synergy with advanced neutron optics and spectrometers, will require imaging detectors with better resolution and faster response than presently available. Thus in this work, which is part of a project of the Hahn-Meitner-Institut (HMI), a novel neutron detector has been developed. In the central detector plane a composite foil converter ( sup 1 sup 5 sup 7 Gd/CsI) is located, emitting, after neutron capture and subsequent emission of conversion electrons, a detectable cluster of low-energy electrons. In two adjacent low-pressure gas gaps, sandwiched between fourfold segmented micro-strip gas chamber (MSGC) plates on each side, the clusters are pre-amplified in parallel-plate mode and further in the strong alternating fields between the micro-strips. The advanced micro-strip design is made in multilayer technology on a robust glass substrate. Two closely spaced electrode planes are used for two-dimensional position readout. The expected position resolution is 0.1 - ...

  15. The Frankfurt neutron source FRANZ

    Science.gov (United States)

    Alzubaidi, Suha; Bartz, Ulrich; Basten, Markus; Bechtold, Alexander; Chau, Long Phi; Claessens, Christine; Dinter, Hannes; Droba, Martin; Fix, Christopher; Hähnel, Hendrik; Heilmann, Manuel; Hinrichs, Ole; Huneck, Simon; Klump, Batu; Lotz, Marcel; Mäder, Dominik; Meusel, Oliver; Noll, Daniel; Nowottnick, Tobias; Obermayer, Marcus; Payir, Onur; Petry, Nils; Podlech, Holger; Ratzinger, Ulrich; Schempp, Alwin; Schmidt, Stefan; Schneider, Philipp; Seibel, Anja; Schwarz, Malte; Schweizer, Waldemar; Volk, Klaus; Wagner, Christopher; Wiesner, Christoph

    2016-05-01

    A 2MeV proton beam will produce a quasi-Maxwellian neutron spectrum of around 30 keV by the 7Li(p, n)7Be reaction. The experiments are mainly focused on the measurement of differential neutron capture cross sections relevant for the astrophysical s-process in nuclear synthesis. Moreover, proton capture cross sections for the astrophysical p-process can be measured directly with the proton beam. For an efficient time of flight measurement of the neutron energies along the 0.7 m long drift from the Li-target to the sample, 1ns short, intense proton pulses are needed at the target. Additionally, to reach 107 n/cm2/s at the sample, a pulse repetition rate of 250 kHz is intended. After completion and successful running in, FRANZ will become a user facility with internal and external users. The 120 kV injector terminal and the 200mA proton source as well as the low-energy beam transport section and the FRANZ cave have been realized successfully. The 1.9 MV RF accelerator consists of a combined 4-Rod-RFQ/IH-DTL-resonator and is in the RF tuning and power testing phase. The 2 MeV transport and rebuncher section is ready for installation. In a first step FRANZ will offer experimental areas for neutron activation experiments and for proton beam experiments, as mentioned above. From the accelerator physics point of view, FRANZ will be an excellent facility for high current beam investigations and for beam wall interaction studies.

  16. First tests of the applicability of $\\gamma$-ray imaging for background discrimination in time-of-flight neutron capture measurements

    CERN Document Server

    Magán, D L Pérez; Domingo-Pardo, C; Agramunt-Ros, J; Albiol, F; Casanovas, A; González, A; Guerrero, C; Lerendegui-Marco, J; Tarifeño-Saldivia, A

    2016-01-01

    In this work we explore for the first time the applicability of using $\\gamma$-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr$_3$ scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a $^{197}$Au sample have been carried out at n\\_TOF, achieving an enhancement of a factor of 2 in the signal-to-background ratio when selecting only those events coming from the direction of the sample.

  17. First tests of the applicability of γ-ray imaging for background discrimination in time-of-flight neutron capture measurements

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Magán, D.L.; Caballero, L. [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Domingo-Pardo, C., E-mail: domingo@ific.uv.es [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Agramunt-Ros, J.; Albiol, F. [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Casanovas, A. [Institut de Tècniques Energètiques – Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain); González, A. [Institute for Instrumentation in Molecular Imaging, I3M-CSIC 46022 Valencia (Spain); Guerrero, C.; Lerendegui-Marco, J. [Dto. de Física Atómica, Molecular y Nuclear, Universidad de Sevilla, 41012 Sevilla (Spain); Tarifeño-Saldivia, A. [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Institut de Tècniques Energètiques – Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, 08028 Barcelona (Spain)

    2016-07-01

    In this work we explore for the first time the applicability of using γ-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr{sub 3} scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a {sup 197}Au sample have been carried out at n-TOF, achieving an enhancement of a factor of two in the signal-to-background ratio when selecting only those events coming from the direction of the sample.

  18. Data acquisition system for the neutron scattering instruments at the intense pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.; Daly, R.T.; Haumann, J.R.; Hitterman, R.L.; Morgan, C.B.; Ostrowski, G.E.; Worlton, T.G.

    1981-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a major new user-oriented facility which is now coming on line for basic research in neutron scattering and neutron radiation damage. This paper describes the data-acquisition system which will handle data acquisition and instrument control for the time-of-flight neutron-scattering instruments at IPNS. This discussion covers the scientific and operational requirements for this system, and the system architecture that was chosen to satisfy these requirements. It also provides an overview of the current system implementation including brief descriptions of the hardware and software which have been developed.

  19. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  20. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  1. Vacuum ultraviolet lamp based magnetic field enhanced photoelectron ionization and single photon ionization source for online time-of-flight mass spectrometry.

    Science.gov (United States)

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

    2011-12-01

    A magnetic field enhanced photoelectron ionization (MEPEI) source combined with single photon ionization (SPI) was developed for an orthogonal acceleration time-of-flight mass spectrometer (oaTOFMS). A commercial radio frequency (rf) powered vacuum ultraviolet (VUV) lamp was used as SPI light source, and the photoelectrons generated by photoelectric effect were accelerated to induce electron ionization (EI). The MEPEI was obtained by applying a magnetic field of about 800 G with a permanent annular magnet. Compared to a nonmagnetic field photoelectron ionization source, the signal intensities for SO(2), SF(6), O(2), and N(2) in MEPEI were improved more than 2 orders with the photoelectron energy around 20 eV, while most of the characteristics of soft ionization still remained. Simulation with SIMION showed that the sensitivity enhancement in MEPEI was ascribed to the increase of the electron moving path and the improvement of the electrons transmission. The limits of detection for SO(2) and benzene were 750 and 80 ppbv within a detection time of 4 s, respectively. The advantages of the source, including broad range of ionizable compounds, reduced fragments, and good sensitivity with low energy MEPEI, were demonstrated by monitoring pyrolysis products of polyvinyl chloride (PVC) and the intermediate products in discharging of the SF(6) gas inpurity.

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

    Science.gov (United States)

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

    2017-10-01

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

  3. Sequencing of phosphopeptides sulfonated by 4-sulfophenyl isothiocyanate using post-source decay matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    TANG Jianguang; WANG Yongjun; ZHANG Hainan; WANG Chunyu; HU Zhiping; XUE Zhigang; XIA Kun; SHI Xiaoliu

    2006-01-01

    Phosphorylation/dephosphorylation is probably the most common and important reversible post-translational modificaion of proteins. Analyzing the functional effects of phosphorylation is helpful for understanding the biological functions of proteins. Identification of the phosphorylation sites of phosphorylated protein is a prerequisite for research on phosphorylation. In this work, an effective and simple method of identification of protein phosphorylation sites has been developed. Phosphopeptides were selectively enriched with immobilized metal affinity chromatography (IMAC) and subsequently chemically modified by 4-sulfophenyl isothiocyanate, and then the chemically modified phosphopeptides were sequenced with post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI)time-of-flight mass spectrometry for detecting phosphorylation sites. The charge of derivatization by 4-sulfophenyl isothiocyanate introduces a negative sulfonic acid group at the N-terminus of a peptide, and enables the selective detection of only a single series of C-terminal y-type ions. This chemically assisted method greatly simplifies the extremely complex pattern of PSD fragment ions and makes the PSD spectra more easier to be interpreted. The phosphorylation sites of a synthesized model phosphopeptide and human c-myc protein have been successfully identified by this method.Phosphorylation/dephosphorylation is probably the most common and important reversible post-translational modificaion of proteins. Analyzing the functional effects of phosphorylation is helpful for understanding the biological functions of proteins. Identification of the phosphorylation sites of phosphorylated protein is a prerequisite for research on phosphorylation. In this work, an effective and simple method of identification of protein phosphorylation sites has been developed. Phosphopeptides were selectively enriched with immobilized metal affinity chromatography (IMAC) and subsequently chemically

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

    Science.gov (United States)

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

    2011-07-01

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

  5. Analysis methods of neutrons induced resonances in the transmission experiments by time-of-flight and automation of these methods on IBM 7094 II computer; Methode d'analyse des resonances induites par les neutrons dans les experiences de transmission par temps-de-vol et automatisation de ces methodes sur ordinateur IBM-7094 II

    Energy Technology Data Exchange (ETDEWEB)

    Corge, C

    1967-07-01

    The neutron induced resonances analysis aims to determine the neutrons characteristics, leading to the excitation energies, de-excitation probabilities by gamma radiation emission, by neutron emission or by fission, their spin, their parity... This document describes the methods developed, or adapted, the calculation schemes and the algorithms implemented to realize such analysis on a computer, from data obtained during time-of-flight experiments on the linear accelerator of Saclay. (A.L.B.)

  6. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  7. Coded source neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, Philip R [ORNL; Santos-Villalobos, Hector J [ORNL

    2011-01-01

    Coded aperture techniques have been applied to neutron radiography to address limitations in neutron flux and resolution of neutron detectors in a system labeled coded source imaging (CSI). By coding the neutron source, a magnified imaging system is designed with small spot size aperture holes (10 and 100 m) for improved resolution beyond the detector limits and with many holes in the aperture (50% open) to account for flux losses due to the small pinhole size. An introduction to neutron radiography and coded aperture imaging is presented. A system design is developed for a CSI system with a development of equations for limitations on the system based on the coded image requirements and the neutron source characteristics of size and divergence. Simulation has been applied to the design using McStas to provide qualitative measures of performance with simulations of pinhole array objects followed by a quantitative measure through simulation of a tilted edge and calculation of the modulation transfer function (MTF) from the line spread function. MTF results for both 100um and 10um aperture hole diameters show resolutions matching the hole diameters.

  8. Coded source neutron imaging

    Science.gov (United States)

    Bingham, Philip; Santos-Villalobos, Hector; Tobin, Ken

    2011-03-01

    Coded aperture techniques have been applied to neutron radiography to address limitations in neutron flux and resolution of neutron detectors in a system labeled coded source imaging (CSI). By coding the neutron source, a magnified imaging system is designed with small spot size aperture holes (10 and 100μm) for improved resolution beyond the detector limits and with many holes in the aperture (50% open) to account for flux losses due to the small pinhole size. An introduction to neutron radiography and coded aperture imaging is presented. A system design is developed for a CSI system with a development of equations for limitations on the system based on the coded image requirements and the neutron source characteristics of size and divergence. Simulation has been applied to the design using McStas to provide qualitative measures of performance with simulations of pinhole array objects followed by a quantitative measure through simulation of a tilted edge and calculation of the modulation transfer function (MTF) from the line spread function. MTF results for both 100μm and 10μm aperture hole diameters show resolutions matching the hole diameters.

  9. Characterization of high-energy quasi-monoenergetic neutron energy spectra and ambient dose equivalents of 80-389 MeV 7Li(p,n) reactions using a time-of-flight method

    Science.gov (United States)

    Iwamoto, Yosuke; Hagiwara, Masayuki; Satoh, Daiki; Araki, Shouhei; Yashima, Hiroshi; Sato, Tatsuhiko; Masuda, Akihiko; Matsumoto, Tetsuro; Nakao, Noriaki; Shima, Tatsushi; Kin, Tadahiro; Watanabe, Yukinobu; Iwase, Hiroshi; Nakamura, Takashi

    2015-12-01

    We completed a series of measurements on mono-energetic neutron energy spectra of the 7Li(p,n) reaction with 80-389-MeV protons in the 100-m time-of-flight (TOF) tunnel at the Research Center for Nuclear Physics cyclotron facility. For that purpose, we measured neutron energy spectra of the 80-, 100- and 296-MeV proton incident reactions, which had not been investigated in our previous studies. The neutron peak intensity was 0.9-1.1×1010 neutrons/sr/μC in the incident proton energy region of 80-389 MeV, and it was almost independent of the incident proton energy. The contribution of peak intensity of the spectrum to the total intensity integrated with energies above 3 MeV varied between 0.38 and 0.48 in the incident proton energy range of 80-389 MeV. To consider the correction required to derive a response in the peak region from the measured total responses of neutron monitors in the 100-m TOF tunnel, we proposed the subtraction method using energy spectra between 0° and 25°. The normalizing factor k against 25° neutron fluence to equalize it to 0° neutron fluence in the continuum region ranges from 0.74 to 1.02 depending on the incident proton energy and angle measured. Even without the TOF method, the subtraction method with the k factor almost decreases the response in the continuum region of a neutron spectrum against the total response of neutron monitors.

  10. Time-of-flight magnetic resonance angiography for follow-up of coil embolization with enterprise stent intracranial aneurysm: Usefulness of source images

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Dae; Kim, Kang Min; Lee, Woong Jae; Sohn, Chul Ho; Kang, Hyun Seung; Kim, Jeong Eun; Han, Moon Hee [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-02-15

    The aim of this study was to determine the interobserver and intermodality agreement in the interpretation of time-of-flight (TOF) MR angiography (MRA) for the follow-up of coiled intracranial aneurysms with the Enterprise stent. Two experienced neurointerventionists independently reviewed the follow-up MRA studies of 40 consecutive patients with 44 coiled aneurysms. All aneurysms were treated with assistance from the Enterprise stent and the radiologic follow-up intervals were greater than 6 months after the endovascular therapy. Digital subtraction angiography (DSA) served as the reference standard. The degree of aneurysm occlusion was determined by an evaluation of the maximal intensity projection (MIP) and source images (SI) of the TOF MRA. The capability of the TOF MRA to depict the residual flow within the coiled aneurysms and the stented parent arteries was compared with that of the DSA. DSA showed stable occlusions in 25 aneurysms, minor recanalization in 8, and major recanalization in 11. Comparisons between the TOF MRA and conventional angiography showed that the MIP plus SI had almost perfect agreement (κ = 0.892, range 0.767 to 1.000) and had better agreement than with the MIP images only ((κ = 0.598, range 0.370 to 0.826). In-stent stenosis of more than 33% was observed in 5 cases. Both MIP and SI of the MRA showed poor depiction of in-stent stenosis compared with the DSA. TOF MRA seemed to be reliable in screening for aneurysm recurrence after coil embolization with Enterprise stent assistance, especially in the evaluation of the SI, in addition to MIP images in the TOF MRA.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

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

  12. Measurements of the neutron brightness from a phase II solid methane moderator at the LENS neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Shin Yunchang, E-mail: yunchang.shin@yale.ed [Department of Physics, Indiana University Bloomington, IN 47408 (United States); Department of Physics, Yale University, New Haven, CT 06511 (United States); Lavelle, C.M.; Mike Snow, W.; Baxter, David V.; Tong Xin; Yan Haiyang [Department of Physics, Indiana University Bloomington, IN 47408 (United States); Leuschner, Mark [ProCure 420 North Walnut Street Bloomington, IN 47404 (United States)

    2010-08-21

    Measurements of the neutron brightness from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at the Indiana University Cyclotron Facility (IUCF) to characterize the source and to test our new neutron scattering model of phase II solid methane . A time-of-flight method was used to measure the neutron energy spectrum from the moderator in the energy range of 0.1 meV {approx}1eV. Neutrons were counted with a high efficiency {sup 3}He detector. The solid methane in the moderator occupied phase II and the energy spectra were measured at 20 K and 4 K. We tested our newly developed scattering kernels for phase II solid methane by calculating the neutron brightness expected from the methane moderator at the LENS neutron source using MCNP (Monte Carlo N-particle Transport Code). Within the accuracy of our approximate approach, our model correctly predicts the neutron brightness at both temperatures.

  13. Minimizing the background radiation in the new neutron time-of-flight facility at CERN FLUKA Monte Carlo simulations for the optimization of the n_TOF second experimental line

    CERN Document Server

    Bergström, Ida; Elfgren, Erik

    2013-06-11

    At the particle physics laboratory CERN in Geneva, Switzerland, the Neutron Time-of-Flight facility has recently started the construction of a second experimental line. The new neutron beam line will unavoidably induce radiation in both the experimental area and in nearby accessible areas. Computer simulations for the minimization of the background were carried out using the FLUKA Monte Carlo simulation package. The background radiation in the new experimental area needs to be kept to a minimum during measurements. This was studied with focus on the contributions from backscattering in the beam dump. The beam dump was originally designed for shielding the outside area using a block of iron covered in concrete. However, the backscattering was never studied in detail. In this thesis, the fluences (i.e. the flux integrated over time) of neutrons and photons were studied in the experimental area while the beam dump design was modified. An optimized design was obtained by stopping the fast neutrons in a high Z mat...

  14. Characterizing a fast-response, low-afterglow liquid scintillator for neutron time-of-flight diagnostics in fast ignition experiments

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Y., E-mail: abe-y@ile.osaka-u.ac.jp; Hosoda, H.; Arikawa, Y.; Nagai, T.; Kojima, S.; Sakata, S.; Inoue, H.; Iwasa, Y.; Iwano, K.; Yamanoi, K.; Fujioka, S.; Nakai, M.; Sarukura, N.; Shiraga, H.; Norimatsu, T.; Azechi, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2014-11-15

    The characteristics of oxygen-enriched liquid scintillators with very low afterglow are investigated and optimized for application to a single-hit neutron spectrometer for fast ignition experiments. It is found that 1,2,4-trimethylbenzene has better characteristics as a liquid scintillator solvent than the conventional solvent, p-xylene. In addition, a benzophenon-doped BBQ liquid scintillator is shown to demonstrate very rapid time response, and therefore has potential for further use in neutron diagnostics with fast time resolution.

  15. ALICE Time Of Flight Detector

    CERN Multimedia

    Alici, A

    2013-01-01

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

  16. Dynamics in γ-Fe2O3 nanoparticles studied by time-of-flight polarized neutron scattering

    DEFF Research Database (Denmark)

    Kuhn, L.T.; Lefmann, K.; Klausen, S.N.;

    2004-01-01

    The inelastic neutron-scattering signal from magnetic nanoparticles contains information on magnetic dynamics like superparamagnetic relaxation and collective magnetic excitations. Often another, very broad quasi-elastic component is observed in addition. We have studied this quasi-elastic neutro...... of disordered surface spins and vibrations of individual nanoparticles. (C) 2004 Elsevier B.V. All rights reserved....

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

    Science.gov (United States)

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

    2017-08-21

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

  18. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n){sup 4}He and D(d,n){sup 3}He reaction yield and ion temperature on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, C. J., E-mail: cforrest@lle.rochester.edu; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Romanofsky, M. H.; Sangster, T. C.; Shoup, M. J.; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2016-11-15

    Upgraded microchannel-plate–based photomultiplier tubes (MCP-PMT’s) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C{sub 15}H{sub 11}NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT’s, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 10{sup 6}. With these enhancements, the 13.4-m nTOF can measure the D(t,n){sup 4}He and D(d,n){sup 3}He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 10{sup 9} to 1 × 10{sup 14} and the ion temperature with an accuracy approaching 5% for both the D(t,n){sup 4}He and D(d,n){sup 3}He reactions.

  19. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n)(4)He and D(d,n)(3)He reaction yield and ion temperature on OMEGA.

    Science.gov (United States)

    Forrest, C J; Glebov, V Yu; Goncharov, V N; Knauer, J P; Radha, P B; Regan, S P; Romanofsky, M H; Sangster, T C; Shoup, M J; Stoeckl, C

    2016-11-01

    Upgraded microchannel-plate-based photomultiplier tubes (MCP-PMT's) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C15H11NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT's, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 10(6). With these enhancements, the 13.4-m nTOF can measure the D(t,n)(4)He and D(d,n)(3)He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 10(9) to 1 × 10(14) and the ion temperature with an accuracy approaching 5% for both the D(t,n)(4)He and D(d,n)(3)He reactions.

  20. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n)4He and D(d,n)3He reaction yield and ion temperature on OMEGA

    Science.gov (United States)

    Forrest, C. J.; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Romanofsky, M. H.; Sangster, T. C.; Shoup, M. J.; Stoeckl, C.

    2016-11-01

    Upgraded microchannel-plate-based photomultiplier tubes (MCP-PMT's) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C15H11NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT's, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 106. With these enhancements, the 13.4-m nTOF can measure the D(t,n)4He and D(d,n)3He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 109 to 1 × 1014 and the ion temperature with an accuracy approaching 5% for both the D(t,n)4He and D(d,n)3He reactions.

  1. The Neutron Energy Spectrum Study from the Phase II Solid Methane Moderator at the LENS Neutron Source

    OpenAIRE

    Shin, Yunchang; Snow, W. Mike; Lavelle, Christopher M.; Baxter, David V.; Tong, Xin; Yan, Haiyang; Leuschner, Mark

    2007-01-01

    Neutron energy spectrum measurements from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at Indiana University Cyclotron Facility (IUCF) to verify our neutron scattering model of solid methane. The time-of-flight method was used to measure the energy spectrum of the moderator in the energy range of 0.1$meV\\sim$ 1$eV$. Neutrons were counted with a high efficiency $^{3}{He}$ detector. The solid methane moderator was operated in phase II temperature and the ener...

  2. Development of time-of-flight neutron detector with fast-decay and low-afterglow scintillator for fast ignition experiment

    Directory of Open Access Journals (Sweden)

    Nagai T.

    2013-11-01

    Full Text Available A fast-decay and low-afterglow liquid scintillator was developed for the fast ignition experiment at the Institute of Laser Engineering (ILE. The liquid scintillator was coupled to a gated photomultiplier (PMT, and the gating performance under high-intensity γ-rays was experimentally checked. In 2010, a detector with a high detection efficiency of 10−4 was developed and installed in this experiment. The neutron yield in the fast heating experiment was successfully measured using this detector.

  3. FAST NEUTRON SOURCE DETECTION AT LONG DISTANCES USING DOUBLE SCATTER SPECTROMETRY.

    Energy Technology Data Exchange (ETDEWEB)

    FORMAN,L.VANIER,P.WELSH,K.

    2003-08-03

    Fast neutrons can be detected with relatively high efficiency, >15%, using two planes of hydrogenous scintillator detectors where a scatter in the first plane creates a start pulse and scatter in the second plane is separated by time-of-flight. Indeed, the neutron spectrum of the source can be determined as the sum of energy deposited by pulse height in the first added to the energy of the second found by time-of-flight to the second detector. Gamma rays can also create a double scatter by Compton interaction in the first with detection in the second, but these events occur in a single time window because the scattered photons all travel at the speed of light. Thus, gamma ray events can be separated from neutrons by the time-of-flight differences. We have studied this detection system with a Cf-252 source using Bicron 501A organic scintillators and report on the ability to efficiently detect fast neutrons with high neutron/gamma detection ratios. We have further studied cosmic-ray neutron background detection response that is the dominant background in long range detection. We have found that most of the neutrons are excluded from the time-of-flight window because they are either too high in energy, >10 keV, or too low, < 10 keV. Moreover, if the detection planes are position-sensitive, the angular direction of the source can be determined by the ratio of the energy of scattered protons in the first detector relative to the position and energy of the scattered neutron detected in the second. This ability to locate the source in theta is useful, but more importantly increases the signal to noise relative to cosmic-ray produced neutrons that are relatively isotropic. This technique may be used in large arrays to detect neutrons at ranges up to 0.5 kilometer.

  4. In-situ time-of-flight neutron diffraction of ErD2 (beta phase) formation during D2 loading.

    Energy Technology Data Exchange (ETDEWEB)

    Browning, James Frederick (Oak Ridge National Laboratory, Oak Ridge, TN); Llobet, Anna (Los Alamos National Laboratory, Los Alamos, NM); Snow, Clark Sheldon; Rodriguez, Mark Andrew; Wixom, Ryan R.

    2008-06-01

    In an effort to better understand the structural changes occurring during hydrogen loading of erbium target materials, we have performed D{sub 2} loading of erbium metal (powder) with simultaneous neutron diffraction analysis. This experiment tracked the conversion of Er metal to the {alpha} erbium deuteride (solid-solution) phase and then on to the {beta} (fluorite) phase. Complete conversion to ErD{sub 2.0} was accomplished at 10 Torr D{sub 2} pressure with deuterium fully occupying the tetrahedral sites in the fluorite lattice. Increased D{sub 2} pressure (up to 500 Torr at 450 C) revealed {approx}10 % deuterium occupation of the octahedral sites. Subsequent vacuum pumping of the sample at 450 C removed octahedral site occupancy while maintaining tetrahedral deuterium occupancy, thereby yielding stoichiometric ErD{sub 2.0} {beta} phase.

  5. Characterization of the sources and processes of organic and inorganic aerosols in New York City with a high-resolution time-of-flight aerosol mass spectrometer

    Directory of Open Access Journals (Sweden)

    Y.-L. Sun

    2010-10-01

    Full Text Available Submicron aerosol particles (PM1 were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS during the summer 2009 Field Intensive Study at Queens College in New York City. Organic aerosol (OA and sulfate are the two dominant species, accounting for 54% and 24%, respectively, of total PM1 mass on average. The average mass size distribution of OA presents a small mode peaking at ~150 nm (Dva in addition to an accumulation mode (~550 nm that is internally mixed with sulfate, nitrate, and ammonium. The diurnal cycles of sulfate and OA both show pronounced peaks between 01:00–02:00 p.m. EST due to photochemical production. The average (±1σ oxygen-to-carbon (O/C, hydrogen-to-carbon (H/C, and nitrogen-to-carbon (N/C ratios of OA in NYC are 0.36 (±0.09, 1.49 (±0.08, and 0.012(±0.005, respectively, corresponding to an average organic mass-to-carbon (OM/OC ratio of 1.62(±0.11. Positive matrix factorization (PMF of the high resolution mass spectra identified five OA components: a hydrocarbon-like OA (HOA, two types of oxygenated OA (OOA including a low-volatility OOA (LV-OOA and a semi-volatile OOA (SV-OOA, a cooking-emission related OA (COA, and a unique nitrogen-enriched OA (NOA. HOA appears to represent primary OA (POA from urban traffic emissions. It comprises primarily of reduced species (H/C=1.83; O/C=0.06 and shows a mass spectral pattern very similar to those of POA from fossil fuel combustion, and correlates tightly with traffic emission tracers including elemental carbon and NOx. LV-OOA, which is highly oxidized (O/C=0.63 and correlates well with sulfate, appears to be representative for regional, aged secondary OA (SOA. SV-OOA, which is less oxidized (O/C=0.38 and correlates well with non-refractory chloride, likely represents less photo-chemically aged, semi-volatile SOA. COA shows a similar spectral pattern to the reference spectra of POA from

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

    Science.gov (United States)

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

    2017-06-01

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

  7. Glycine zinc sulfate penta­hydrate: redetermination at 10 K from time-of-flight neutron Laue diffraction

    Science.gov (United States)

    Fortes, A. Dominic; Howard, Christopher M.; Wood, Ian G.; Gutmann, Matthias J.

    2016-01-01

    Single crystals of glycine zinc sulfate penta­hydrate [systematic name: hexa­aqua­zinc tetra­aquadiglycinezinc bis­(sulfate)], [Zn(H2O)6][Zn(C2H5NO2)2(H2O)4](SO4)2, have been grown by isothermal evaporation from aqueous solution at room temperature and characterized by single-crystal neutron diffraction. The unit cell contains two unique ZnO6 octa­hedra on sites of symmetry -1 and two SO4 tetra­hedra with site symmetry 1; the octa­hedra comprise one [tetra­aqua-diglycine zinc]2+ ion (centred on one Zn atom) and one [hexa­aqua­zinc]2+ ion (centred on the other Zn atom); the glycine zwitterion, NH3 +CH2COO−, adopts a monodentate coordination to the first Zn atom. All other atoms sit on general positions of site symmetry 1. Glycine forms centrosymmetric closed cyclic dimers due to N—H⋯O hydrogen bonds between the amine and carboxyl­ate groups of adjacent zwitterions and exhibits torsion angles varying from ideal planarity by no more than 1.2°, the smallest values for any known glycine zwitterion not otherwise constrained by a mirror plane. This work confirms the H-atom locations estimated in three earlier single-crystal X-ray diffraction studies with the addition of independently refined fractional coordinates and Uij parameters, which provide accurate inter­nuclear X—H (X = N, O) bond lengths and consequently a more accurate and precise depiction of the hydrogen-bond framework. PMID:27746937

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  9. Neutron imaging of radioactive sources

    Science.gov (United States)

    Hameed, F.; Karimzadeh, S.; Zawisky, M.

    2008-08-01

    Isotopic neutron sources have been available for more than six decades. At the Atomic Institute in Vienna, operating a 250 kW TRIGA reactor, different neutron sources are in use for instrument calibration and fast neutron applications but we have only little information about their construction and densities. The knowledge of source design is essential for a complete MCNP5 modeling of the experiments. Neutron radiography (NR) and neutron tomography (NT) are the best choices for the non-destructive inspection of the source geometry and homogeneity. From the transmission analysis we gain information about the shielding components and the densities of the radio-isotopes in the cores. Three neutron sources, based on (alpha, n) reaction, have been investigated, two 239PuBe sources and one 241AmBe source. In the NR images the internal structure was clearly revealed using high-resolving scintillation and imaging plate detectors. In one source tablet a crack was detected which causes asymmetric neutron emission. The tomography inspection of strong absorbing materials is more challenging due to the low beam intensity of 1.3x105 n/cm2s at our NT instrument, and due to the beam hardening effect which requires an extension of reconstruction software. The tomographic inspection of a PuBe neutron source and appropriate measures for background and beam hardening correction are presented.

  10. Ukraine experimental neutron source facility.

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Y.; Bolshinsky, I.; Nekludov, I.; Karnaukhov, I. (Nuclear Engineering Division); (INL); (Kharkov Institute of Physics and Technology)

    2008-01-01

    Kharkov Institute of Physics and Technology (KIPT) of Ukraine has a plan to construct an experimental neutron source facility. The facility has been developed for producing medical isotopes, training young nuclear professionals, supporting the Ukraine nuclear industry, providing capability for performing reactor physics, material research, and basic science experiments. Argonne National Laboratory (ANL) of USA is collaborating with KIPT on developing this facility. A driven subcritical assembly utilizing the KIPT electron accelerator with a target assembly is used to generate the neutron source. The target assembly utilizes tungsten or uranium for neutron production through photonuclear reactions with 100-KW of electron beam power. The neutron source intensity, spectrum, and spatial distribution have been studied to maximize the neutron yield and satisfy different engineering requirements. The subcritical assembly is designed to obtain the highest possible neutron flux intensity with a subcriticality of 0.98. Low enrichment uranium is used for the fuel material because it enhances the neutron source performance. Safety, reliability, and environmental considerations are included in the facility conceptual design. Horizontal neutron channels are incorporated for performing basic research including cold neutron source. This paper describes the conceptual design and summarizes some of the related analyses.

  11. Some general reflections on {open_quotes}long pulse{close_quotes} neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Inst., Villigen (Switzerland)

    1995-12-31

    A long pulse spallation neutron source (LPSS) having about 20 times more time average thermal flux than its short pulse counterpart (SPSS) at the same proton beam power and featuring a pronounced time structure not available on CW sources (CWNS) of equal time average flux can in principle host instruments typical for both classes of facilities. While the need for additional choppers introduces some restrictions on inverted time of flight techniques typical for SPSS and high incident neutron energies are not easier to use on LPSS than on CWNS, taking advantage of the pulsed nature of the neutron flux can enhance significantly the performance of direct time of flight instruments and of crystal spectrometers or diffractometers. In the paper some of the options are reviewed in a general manner and criteria are discussed which can be used to optimize the performance enhancement.

  12. A drabkin energy filter for experiments at a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Parizzi, A.A.; Klose, F. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Felcher, G.P. [Materials Science Division, Argonne National Laboratory, Argonne, IL (United States)

    2001-03-01

    We present a new approach for dynamic monochromatization of neutrons suitable for time-of-flight experiments at spallation neutron sources. The method requires polarized neutrons and is based on the Drabkin energy filter. In its initial application, this magnetic resonator device, consisting of a polarizer/analyzer system and a wavelength-dependent spin flipper, was proposed for extracting a narrow bandwidth from a broad bandwidth polarized neutron beam. At a spallation neutron source, wavelength is determined by time-of-flight (TOF) from the source to the detector. However, at each instant a spread of wavelengths is recorded due to the non-zero emission time-width of the source/moderator system. Particularly, high-intensity moderators for cold neutrons produce long 'tails' in the intensity/time distribution for all wavelengths, limiting the resolution of the experiments. The Drabkin energy filter can be used to cut the neutron tails for all wavelengths, by drifting the resonance condition in synchronization with the TOF. Calculations show that the method is viable, and that substantial resolution gains are obtainable by application to a TOF neutron reflectometer. (author)

  13. A Drabkin energy filter for experiments at a spallation neutron source.

    Energy Technology Data Exchange (ETDEWEB)

    Parizzi, A. A.; Felcher, G. P.; Klose, F.

    2000-11-21

    We present a new approach for dynamic monochromatization of neutrons suitable for time-of-flight experiments at spallation neutron sources. The method requires polarized neutrons and is based on the Drabkin energy filter. In its initial application, this magnetic resonator device, consisting of a polarizer/analyzer system and a wavelength-dependent spin flipper, was proposed for extracting a narrow bandwidth from a broad bandwidth polarized neutron beam. At a spallation neutron source, wavelength is determined by time-of-flight (TOF) from the source to the detector. However, at each instant a spread of wavelengths is recorded due to the non-zero emission time of the source/moderator system. Particularly, high-intensity moderators for cold neutrons produce long ''tails'' in the intensity/time distribution for all wavelengths, degrading the resolution of the experiments. The Drabkin energy filter can be used to cut the neutron tails for all wavelengths, by drifting the resonance condition in synchronization with the TOF. Calculations show that the method is viable, and that substantial resolution gains are obtained by application to a TOF neutron reflectometer.

  14. Advanced Neutron Source (ANS) Project

    Science.gov (United States)

    Campbell, J. H.

    1992-01-01

    This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I & C Research and Development; Design; and Safety.

  15. Intense pulsed neutron source

    Science.gov (United States)

    The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and 'in press' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

  16. Materials for spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, W.F.; Daemen, L.L. [comps.

    1996-03-01

    The Workshop on Materials for Spallation Neutron Sources at the Los Alamos Neutron Science Center, February 6 to 10, 1995, gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss areas in which work is needed, successful designs and use of materials, and opportunities for further studies. During the first day of the workshop, speakers presented overviews of current spallation neutron sources. During the next 3 days, seven panels allowed speakers to present information on a variety of topics ranging from experimental and theoretical considerations on radiation damage to materials safety issues. An attempt was made to identify specific problems that require attention within the context of spallation neutron sources. This proceedings is a collection of summaries from the overview sessions and the panel presentations.

  17. Miniaturised Time-of-Flight Mass Spectrometer

    Science.gov (United States)

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

    2004-04-01

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

  18. Thulium-169 neutron inelastic scattering cross section measurements via the sup 1 sup 6 sup 9 Tm(n,n'gamma) reaction 25.40.fq; Inelastic neutron scattering; Nuclear reactions 169Tm(n,n'gamma); gamma-branching ratios; Neutron inelastic level cross sections; Compound and direct nuclear interaction; Time-of-flight method; High purity Ge detector

    CERN Document Server

    Ko, Y J; Kegel, G H R; Desimone, D J; Seo, P N; Young, P G

    2000-01-01

    Neutron inelastic scattering from thulium-169 has been studied for states above 100 keV via the (n,n'gamma) reaction at incident energies in the 0.2- to 1.0-MeV range. A high-resolution Ge spectrometer in conjunction with the time-of-flight technique was utilized. Thirty-six gamma-ray transitions from 16 levels were observed. Gamma-ray angular distributions were measured at E sub n =750 keV and excitation functions at 125 degrees were measured in 50 keV steps over the range of incident energies. Differential gamma-ray production cross sections and gamma-ray branching ratios were obtained. Inferred neutron inelastic level cross sections of the four lowest ground-state rotational band (K suppi=1/2 sup +) members are compared to the sum of calculated compound nucleus and direct interaction cross sections. For the remaining levels, measurements are compared to compound nucleus calculations only. The comparison shows generally good agreement particularly near threshold.

  19. Optical polarizing neutron devices designed for pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, M.; Kurahashi, K.; Endoh, Y. [Tohoku Univ, Sendai (Japan); Itoh, S. [National Lab. for High Energy Physics, Tsukuba (Japan)

    1997-09-01

    We have designed two polarizing neutron devices for pulsed cold neutrons. The devices have been tested at the pulsed neutron source at the Booster Synchrotron Utilization Facility of the National Laboratory for High Energy Physics. These two devices proved to have a practical use for experiments to investigate condensed matter physics using pulsed cold polarized neutrons.

  20. Inexpensive Time-of-Flight Velocity Measurements.

    Science.gov (United States)

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

    1979-01-01

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

  1. Material recognition using neutron/gamma interrogation with time tagged fission sources

    Energy Technology Data Exchange (ETDEWEB)

    Hao, X.; Lunardon, M.; Moretto, S.; Stevanato, L.; Viesti, G. [Dipartimento di Fisica dell' Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy); Fabris, D.; Nebbia, G; Pesente, S. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Sajo-Bohus, L. [Universidad Simon-Bolivar, Laboratorio Fisica Nuclear, Apartado 8900, 1080 A. Caracas (Venezuela, Bolivarian Republic of)

    2009-07-01

    Material recognition is studied by measuring simultaneously the transmission of neutron and gamma rays produced by a time-tagged {sup 252}Cf source. The possibility to derive direct signatures to identify light elements (C,N,O) by using the measured transmission versus neutron time of flight is demonstrated. The yield of the transmitted gamma ray as a function of energy in the range 0.1-5.5 MeV provides high precision identification of the atomic number of the sample. A tomography system, currently under construction, is described. (authors)

  2. Neutron resonance transmission spectroscopy with high spatial and energy resolution at the J-PARC pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Shinohara, T.; Kai, T.; Ooi, M. [Japan Atomic Energy Agency, 2–4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kamiyama, T.; Kiyanagi, Y.; Shiota, Y. [Hokkaido University, Kita 13 Nishi 8 Kita-ku, Sapporo-shi, Hokkaido 060-8628 (Japan); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2014-05-11

    The sharp variation of neutron attenuation at certain energies specific to particular nuclides (the lower range being from ∼1 eV up to ∼1 keV), can be exploited for the remote mapping of element and/or isotope distributions, as well as temperature probing, within relatively thick samples. Intense pulsed neutron beam-lines at spallation sources combined with a high spatial, high-timing resolution neutron counting detector, provide a unique opportunity to measure neutron transmission spectra through the time-of-flight technique. We present the results of experiments where spatially resolved neutron resonances were measured, at energies up to 50 keV. These experiments were performed with the intense flux low background NOBORU neutron beamline at the J-PARC neutron source and the high timing resolution (∼20 ns at epithermal neutron energies) and spatial resolution (∼55 µm) neutron counting detector using microchannel plates coupled to a Timepix electronic readout. Simultaneous element-specific imaging was carried out for several materials, at a spatial resolution of ∼150 µm. The high timing resolution of our detector combined with the low background beamline, also enabled characterization of the neutron pulse itself – specifically its pulse width, which varies with neutron energy. The results of our measurements are in good agreement with the predicted results for the double pulse structure of the J-PARC facility, which provides two 100 ns-wide proton pulses separated by 600 ns, broadened by the neutron energy moderation process. Thermal neutron radiography can be conducted simultaneously with resonance transmission spectroscopy, and can reveal the internal structure of the samples. The transmission spectra measured in our experiments demonstrate the feasibility of mapping elemental distributions using this non-destructive technique, for those elements (and in certain cases, specific isotopes), which have resonance energies below a few keV, and with lower

  3. Evaluation of a pulsed glow discharge time-of-flight mass spectrometer as a detector for gas chromatography and the influence of the glow discharge source parameters on the information volume in chemical speciation analysis.

    Science.gov (United States)

    Fliegel, Daniel; Fuhrer, Katrin; Gonin, Marc; Günther, Detlef

    2006-09-01

    The figures of merit of a pulsed glow discharge time-of-flight mass spectrometer (GD-TOFMS) as a detector for gas chromatography (GC) analysis were evaluated. The mass resolution for the GD-TOFMS was determined on FWHM in the high mass range (208Pb+) as high as 5,500. Precision of 400 subsequent analyses was calculated on 63Cu+ to be better than 1% RSD with no significant drift over the time of the analysis. Isotope precision based on the 63Cu+/65Cu+ ratio over 400 analyses was 1.5% RSD. The limits of detection for gaseous analytes (toluene in methanol as solvent) were determined to be as low as several hundred ppb or several hundred pg absolute without using any pre-concentration technique. Furthermore, the different GD source parameters like capillary distance, cathode-anode spacing, and GD source pressure with regards to the accessible elemental, structural, and molecular information were evaluated. It was demonstrated that each of these parameters has severe influence on the ratio of elemental, structural, and parent molecular information in chemical speciation analysis.

  4. Liquid chromatography coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry and post-column addition of metal salt solutions as a powerful tool for the metabolic profiling of Fusarium oxysporum.

    Science.gov (United States)

    Cirigliano, Adriana M; Rodriguez, M Alejandra; Gagliano, M Laura; Bertinetti, Brenda V; Godeas, Alicia M; Cabrera, Gabriela M

    2016-03-25

    Fusarium oxysporum L11 is a non-pathogenic soil-borne fungal strain that yielded an extract that showed antifungal activity against phytopathogens. In this study, reversed-phase high-performance liquid chromatography (RP-HPLC) coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry (API-QTOF-MS) was applied for the comprehensive profiling of the metabolites from the extract. The employed sources were electrospray (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). Post-column addition of metal solutions of Ca, Cu and Zn(II) was also tested using ESI. A total of 137 compounds were identified or tentatively identified by matching their accurate mass signals, suggested molecular formulae and MS/MS analysis with previously reported data. Some compounds were isolated and identified by NMR. The extract was rich in cyclic peptides like cyclosporins, diketopiperazines and sansalvamides, most of which were new, and are reported here for the first time. The use of post-column addition of metals resulted in a useful strategy for the discrimination of compound classes since specific adducts were observed for the different compound families. This technique also allowed the screening for compounds with metal binding properties. Thus, the applied methodology is a useful choice for the metabolic profiling of extracts and also for the selection of metabolites with potential biological activities related to interactions with metal ions.

  5. Source-identifying biomarker ions between environmental and clinical Burkholderia pseudomallei using whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS.

    Directory of Open Access Journals (Sweden)

    Suthamat Niyompanich

    Full Text Available Burkholderia pseudomallei is the causative agent of melioidosis, which is an endemic disease in Northeast Thailand and Northern Australia. Environmental reservoirs, including wet soils and muddy water, serve as the major sources for contributing bacterial infection to both humans and animals. The whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (whole-cell MALDI-TOF MS has recently been applied as a rapid, accurate, and high-throughput tool for clinical diagnosis and microbiological research. In this present study, we employed a whole-cell MALDI-TOF MS approach for assessing its potency in clustering a total of 11 different B. pseudomallei isolates (consisting of 5 environmental and 6 clinical isolates with respect to their origins and to further investigate the source-identifying biomarker ions belonging to each bacterial group. The cluster analysis demonstrated that six out of eleven isolates were grouped correctly to their sources. Our results revealed a total of ten source-identifying biomarker ions, which exhibited statistically significant differences in peak intensity between average environmental and clinical mass spectra using ClinProTools software. Six out of ten mass ions were assigned as environmental-identifying biomarker ions (EIBIs, including, m/z 4,056, 4,214, 5,814, 7,545, 7,895, and 8,112, whereas the remaining four mass ions were defined as clinical-identifying biomarker ions (CIBIs consisting of m/z 3,658, 6,322, 7,035, and 7,984. Hence, our findings represented, for the first time, the source-specific biomarkers of environmental and clinical B. pseudomallei.

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

    Science.gov (United States)

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

    2015-03-01

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

  7. Outline of spallation neutron source engineering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2001-01-01

    Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

  8. The Neutron Energy Spectrum Study from the Phase II Solid Methane Moderator at the LENS Neutron Source

    CERN Document Server

    Shin, Yunchang; Lavelle, Christopher M; Baxter, David V; Tong, Xin; Yan, Haiyang; Leuschner, Mark

    2007-01-01

    Neutron energy spectrum measurements from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at Indiana University Cyclotron Facility (IUCF) to verify our neutron scattering model of solid methane. The time-of-flight method was used to measure the energy spectrum of the moderator in the energy range of 0.1$meV\\sim$ 1$eV$. Neutrons were counted with a high efficiency $^{3}{He}$ detector. The solid methane moderator was operated in phase II temperature and the energy spectra were measured at the temperatures of 20K and 4K. We have also tested our newly-developed scattering kernels for phase II solid methane by calculating the neutron spectral intensity expected from the methane moderator at the LENS neutron source using MCNP (Monte Carlo N-particle Transport Code). Within the expected accuracy of our approximate approach, our model predicts both the neutron spectral intensity and the optimal thickness of the moderator at both temperatures. The predictions are compared to the measur...

  9. Thin Time-Of-Flight PET project

    CERN Multimedia

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

  10. ALICE Time of Flight Construction of MRPCs

    CERN Multimedia

    2003-01-01

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

  11. Compact ultrafast orthogonal acceleration time-of-flight mass spectrometer for on-line gas analysis by electron impact ionization and soft single photon ionization using an electron beam pumped rare gas excimer lamp as VUV-light source.

    Science.gov (United States)

    Mühlberger, F; Saraji-Bozorgzad, M; Gonin, M; Fuhrer, K; Zimmermann, R

    2007-11-01

    Orthogonal acceleration time-of-flight mass spectrometers (oaTOFMS), which are exhibiting a pulsed orthogonal extraction of ion bunches into the TOF mass analyzer from a continuous primary ion beam, are well-suited for continuous ionization methods such as electron impact ionization (EI). Recently an electron beam pumped rare gas excimer lamp (EBEL) was introduced, which emits intensive vacuum UV (VUV) radiation at, e.g., 126 nm (argon excimer) and is well suited as the light source for soft single photon ionization (SPI) of organic molecules. In this paper, a new compact oaTOFMS system which allows switching between SPI, using VUV-light from an EBEL-light source, and conventional EI is described. With the oaTOFMS system, EBEL-SPI and EI mass spectral transients can be recorded at very high repetition rates (up to 100 kHz), enabling high duty cycles and therefore good detection efficiencies. By using a transient recorder card with the capability to perform on-board accumulation of the oaTOF transients, final mass spectra with a dynamic range of 106 can be saved to the hard disk at a rate of 10 Hz. As it is possible to change the ionization modes (EI and SPI) rapidly, a comprehensive monitoring of complex gases with highly dynamic compositions, such as cigarette smoke, is possible. In this context, the EI based mass spectra address the bulk composition (compounds such as water, oxygen, carbon dioxide, etc. in the up to percentage concentration range) as well as some inorganic trace gases such as argon, sulfur dioxide, etc. down to the low ppm level. The EBEL-SPI mass spectra on the other hand are revealing the organic composition down to the lower ppb concentration range.

  12. Neutronic studies of the coupled moderators for spallation neutron sources

    Institute of Scientific and Technical Information of China (English)

    Yin Wen; Liang Jiu-Qing

    2005-01-01

    We investigate the neutronic performance of coupled moderators to be implemented in spallation neutron sources by Monte-Carlo simulation and give the slow neutron spectra for the cold and thermal moderators. CH4 moderator can provide slow neutrons with highly desirable characteristics and will be used in low-power spallation neutron soureces. The slow neutron intensity extracted from different angles has been calculated. The capability of moderation of liquid H2 is lower than H2O and liquid CH4 due to lower atomic number density of hydrogen but we can compensate for this disadvantage by using a premoderator. The H2O premoderator of 2cm thickness can reduce the heat deposition in the cold moderator by about 33% without spoiling the neutron pulse.

  13. PGNAA neutron source moderation setup optimization

    CERN Document Server

    Zhang, Jinzhao

    2013-01-01

    Monte Carlo simulations were carried out to design a prompt {\\gamma}-ray neutron activation analysis (PGNAA) thermal neutron output setup using MCNP5 computer code. In these simulations the moderator materials, reflective materials and structure of the PGNAA 252Cf neutrons of thermal neutron output setup were optimized. Results of the calcuations revealed that the thin layer paraffin and the thick layer of heavy water moderated effect is best for 252Cf neutrons spectrum. The new design compared with the conventional neutron source design, the thermal neutron flux and rate were increased by 3.02 times and 3.27 times. Results indicate that the use of this design should increase the neutron flux of prompt gamma-ray neutron activation analysis significantly.

  14. Development of a new corona discharge based ion source for high resolution time-of-flight chemical ionization mass spectrometer to measure gaseous H2SO4 and aerosol sulfate

    Science.gov (United States)

    Zheng, Jun; Yang, Dongsen; Ma, Yan; Chen, Mindong; Cheng, Jin; Li, Shizheng; Wang, Ming

    2015-10-01

    A new corona discharge (CD) based ion source was developed for a commercial high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) (Aerodyne Research Inc.) to measure both gaseous sulfuric acid (H2SO4) and aerosol sulfate after thermal desorption. Nitrate core ions (NO3-) were used as reagent ions and were generated by a negative discharge in zero air followed by addition of excess nitrogen dioxide (NO2) to convert primary ions and hydroxyl radicals (OH) into NO3- ions and nitric acid (HNO3). The CD-HRToF-CIMS showed no detectable interference from hundreds parts per billion by volume (ppbv) of sulfur dioxide (SO2). Unlike the atmospheric pressure ionization (API) ToF-CIMS, the CD ion source was integrated onto the ion-molecule reaction (IMR) chamber and which made it possible to measure aerosol sulfate by coupling to a filter inlet for gases and aerosols (FIGAERO). Moreover, compared with a quadrupole-based mass spectrometer, the desired HSO4- signal was detected by its exact mass of m/z 96.960, which was well resolved from the potential interferences of HCO3-ṡ(H2O)2 (m/z 97.014) and O-ṡH2OṡHNO3 (m/z 97.002). In this work, using laboratory-generated standards the CD-HRToF-CIMS was demonstrated to be able to detect as low as 3.1 × 105 molecules cm-3 gaseous H2SO4 and 0.5 μg m-3 ammonium sulfate based on 10-s integration time and two times of the baseline noise. The CD ion source had the advantages of low cost and a simple but robust structure. Since the system was non-radioactive and did not require corrosive HNO3 gas, it can be readily field deployed. The CD-HRToF-CIMS can be a powerful tool for both field and laboratory studies of aerosol formation mechanism and the chemical processes that were critical to understand the evolution of aerosols in the atmosphere.

  15. Measurement of neutron diffraction with compact neutron source RANS

    Science.gov (United States)

    Ikeda, Y.; Takamura, M.; Taketani, A.; Sunaga, H.; Otake, Y.; Suzuki, H.; Kumagai, M.; Oba, Y.; Hama, T.

    2016-11-01

    Diffraction is used as a measurement technique for crystal structure. X-rays or electron beam with wavelength that is close to the lattice constant of the crystal is often used for the measurement. They have sensitivity in surface (0.01mm) of heavy metals due to the mean free path for heavy ions. Neutron diffraction has the probe of the internal structure of the heavy metals because it has a longer mean free path than that of the X-rays or the electrons. However, the neutron diffraction measurement is not widely used because large facilities are required in the many neutron sources. RANS (Riken Accelerator-driven Compact Neutron Source) is developed as a neutron source which is usable easily in laboratories and factories. In RANS, fast neutrons are generated by 7MeV protons colliding on a Be target. Some fast neutrons are moderated with polyethylene to thermal neutrons. The thermal neutrons of 10meV which have wavelength of 10nm can be used for the diffraction measurement. In this study, the texture evolution in steels was measured with RANS and the validity of the compact neutron source was proved. The texture of IF steel sheets with the thickness of 1.0mm was measured with 10minutes run. The resolution is 2% and is enough to analyze a evolution in texture due to compression/tensile deformation or a volume fraction of two phases in the steel sample. These results have proven the possibility to use compact neutron source for the analysis of mesoscopic structure of metallic materials.

  16. First flux measurement in a SINQ supermirror neutron guide

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, S.; Schlumpf, N.; Bauer, G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    On Dec. 3, 1996, the Swiss spallation neutron source SINQ was taken into operation and produced its first neutrons successfully. The neutron spectrum within one of the supermirror guides was estimated by a chopper Time-of-Flight method. The result shows a 30% higher neutron intensity at the flux maximum than expected from previous Monte-Carlo simulations. (author) 1 fig., 4 refs.

  17. Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

    Science.gov (United States)

    Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

    VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to μm). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

  18. Observation of Neutron Skyshine from an Accelerator Based Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

    2011-12-13

    A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

  19. Neutron Sources for Standard-Based Testing

    Energy Technology Data Exchange (ETDEWEB)

    Radev, Radoslav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McLean, Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-11-10

    The DHS TC Standards and the consensus ANSI Standards use 252Cf as the neutron source for performance testing because its energy spectrum is similar to the 235U and 239Pu fission sources used in nuclear weapons. An emission rate of 20,000 ± 20% neutrons per second is used for testing of the radiological requirements both in the ANSI standards and the TCS. Determination of the accurate neutron emission rate of the test source is important for maintaining consistency and agreement between testing results obtained at different testing facilities. Several characteristics in the manufacture and the decay of the source need to be understood and accounted for in order to make an accurate measurement of the performance of the neutron detection instrument. Additionally, neutron response characteristics of the particular instrument need to be known and taken into account as well as neutron scattering in the testing environment.

  20. (International Collaboration on Advanced Neutron Sources)

    Energy Technology Data Exchange (ETDEWEB)

    Hayter, J.B.

    1990-11-08

    The International Collaboration on Advanced Neutron Sources was started about a decade ago with the purpose of sharing information throughout the global neutron community. The collaboration has been extremely successful in optimizing the use of resources, and the discussions are open and detailed, with reasons for failure shared as well as reasons for success. Although the meetings have become increasingly oriented toward pulsed neutron sources, many of the neutron instrumentation techniques, such as the development of better monochromators, fast response detectors and various data analysis methods, are highly relevant to the Advanced Neutron Source (ANS). I presented one paper on the ANS, and another on the neutron optical polarizer design work which won a 1989 R D-100 Award. I also gained some valuable design ideas, in particular for the ANS hot source, in discussions with individual researchers from Canada, Western Europe, and Japan.

  1. (International Collaboration on Advanced Neutron Sources)

    Energy Technology Data Exchange (ETDEWEB)

    Hayter, J.B.

    1990-11-08

    The International Collaboration on Advanced Neutron Sources was started about a decade ago with the purpose of sharing information throughout the global neutron community. The collaboration has been extremely successful in optimizing the use of resources, and the discussions are open and detailed, with reasons for failure shared as well as reasons for success. Although the meetings have become increasingly oriented toward pulsed neutron sources, many of the neutron instrumentation techniques, such as the development of better monochromators, fast response detectors and various data analysis methods, are highly relevant to the Advanced Neutron Source (ANS). I presented one paper on the ANS, and another on the neutron optical polarizer design work which won a 1989 R D-100 Award. I also gained some valuable design ideas, in particular for the ANS hot source, in discussions with individual researchers from Canada, Western Europe, and Japan.

  2. Contribution to the study of the interaction of slow neutrons with {sup 235}U using the time-of-flight method; Contribution a l'etude par la methode du temps de vol de l'interaction de neutrons lents avec l'U{sup 235}

    Energy Technology Data Exchange (ETDEWEB)

    Michaudon, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-05-15

    This study concerns the properties of the excited levels of uranium 236 obtained by interaction of slow neutron with uranium 235. The experiments have been carried out at the Saclay linear electron accelerator by use of the time of flight method. In the first part of this paper, we examine the technical and physical conditions which rule the experiments: compromise between resolution and counting rate, time dispersion due to the slowing down of the neutrons and crystalline binding effects. In a second part the experimental results i.e. total, fission and ternary fission cross sections are given. The third part deals with the analysis of these results: the resonance parameters determination ({tau}{sub n}, {tau}{sub {gamma}}, {tau}{sub f}), the study of their statistical distribution and of their correlations. We tried some classifications of the resonances according to their parameters and compared these classifications to each other and to other results. At least the evidence of a cross section correlation with a range smaller than 100 eV seems to be confirmed. (author) [French] Cette etude porte sur les proprietes des niveaux excites de l'Uranium-236 obtenus par l'interaction de neutrons lents avec le {sup 235}U. La technique experimentale est celle de la spectrometrie par temps de vol, les experiences ayant ete realisees aupres de l'accelerateur lineaire d'electrons de Saclay, Dans une premiere partie nous examinons les donnees techniques et physiques conditionnant les experiences: compromis entre resolution et taux de comptage, dispersion en temps due au ralentissement des neutrons, effet des liaisons cristallines. Dans une deuxieme partie sont exposes les resultats experimentaux: sections efficaces totales, de fission et de fission ternaire du {sup 235}U. Une troisieme partie porte sur l'analyse de ces resultats: determination des parametres ({tau}{sub n}, {tau}{sub {gamma}}, {tau}{sub f}), etude de leurs distributions statistiques et

  3. Concentration of the velocity distribution of pulsed neutron beams

    CERN Document Server

    Kitaguchi, Masaaki; Shimizu, Hirohiko M

    2016-01-01

    The velocity of neutrons from a pulsed neutron source is well-defined as a function of their arrival time. Electromagnetic neutron accelerator/decelerator synchronized with the neutron time-of-flight is capable of selectively changing the neutron velocity and concentrating the velocity distribution. Possible enhancement of the neutron intensity at a specific neutron velocity by orders of magnitude is discussed together with an experimental design.

  4. Dose measurements around spallation neutron sources.

    Science.gov (United States)

    Fragopoulou, M; Stoulos, S; Manolopoulou, M; Krivopustov, M; Zamani, M

    2008-01-01

    Neutron dose measurements and calculations around spallation sources appear to be of great importance in shielding research. Two spallation sources were irradiated by high-energy proton beams delivered by the Nuclotron accelerator (JINR), Dubna. Neutrons produced by the spallation sources were measured by using solid-state nuclear track detectors. In addition, neutron dose was calculated after polyethylene and concrete, using a phenomenological model based on empirical relations applied in high-energy physics. The study provides an analytical and experimental neutron benchmark analysis using the transmission factor and a comparison between the experimental results and calculations.

  5. Performance of the prototype LANL solid deuterium ultra-cold neutron source

    CERN Document Server

    Hill, R E; Bowles, T J; Greene, G L; Hogan, G; Lamoreaux, S; Marek, L; Mortenson, R; Morris, C L; Saunders, A; Seestrom, S J; Teasdale, W A; Hoedl, S; Liu, C Y; Smith, D A; Young, A; Filippone, B W; Hua, J; Ito, T; Pasyuk, E A; Geltenbort, P; García, A; Fujikawa, B; Baessler, S; Serebrov, A

    2000-01-01

    A prototype of a solid deuterium (SD sub 2) source of Ultra-Cold Neutrons (UCN) is currently being tested at LANSCE. The source is contained within an assembly consisting of a 4 K polyethylene moderator surrounded by a 77 K beryllium flux trap in which is embedded a spallation target. Time-of-flight measurements have been made of the cold neutron spectrum emerging directly from the flux trap assembly. A comparison is presented of these measurements with results of Monte Carlo (LAHET/MCNP) calculations of the cold neutron fluxes produced in the prototype assembly by a beam of 800 MeV protons incident on the tungsten target. A UCN detector was coupled to the assembly through a guide system with a critical velocity of 8 m/s ( sup 5 sup 8 Ni). The rates and time-of-flight data from this detector are compared with calculated values. Measurements of UCN production as a function of SD sub 2 volume (thickness) are compared with predicted values. The dependence of UCN production on SD sub 2 temperature and proton beam...

  6. Cyclotron-based neutron source for BNCT

    Science.gov (United States)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-01

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation & treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8×109 neutrons/cm2/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  7. Cyclotron-based neutron source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

    2013-04-19

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  8. Neutron scattering instruments for the Spallation Neutron Source (SNS)

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.; Fornek, T. [Argonne National Lab., IL (United States); Herwig, K.W. [Oak Ridge National Lab., TN (United States)

    1998-07-01

    The Spallation Neutron Source (SNS) is a 1 MW pulsed spallation source for neutron scattering planned for construction at Oak Ridge National Laboratory. This facility is being designed as a 5-laboratory collaboration project. This paper addresses the proposed facility layout, the process for selection and construction of neutron scattering instruments at the SNS, the initial planning done on the basis of a reference set of ten instruments, and the plans for research and development (R and D) to support construction of the first ten instruments and to establish the infrastructure to support later development and construction of additional instruments.

  9. Doppler time-of-flight imaging

    KAUST Repository

    Heide, Felix

    2015-07-30

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

  10. The CDF Time of Flight Detector

    Energy Technology Data Exchange (ETDEWEB)

    S. Cabrera et al.

    2004-01-06

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

  11. The TORCH time-of-flight detector

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-11

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

  12. Neutron scattering instrumentation for biology at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Pynn, R. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. In fact, the current generation of pulsed spallation neutron sources, such as LANSCE at Los Alamos and ISIS in the United Kingdom, has demonstrated a capability for small angle scattering (SANS) - a typical cold- neutron application - that was not anticipated five years ago. Although no one has yet built a Laue diffractometer at a pulsed spallation source, calculations show that such an instrument would provide an exceptional capability for protein crystallography at one of the existing high-power spoliation sources. Even more exciting is the prospect of installing such spectrometers either at a next-generation, short-pulse spallation source or at a long-pulse spallation source. A recent Los Alamos study has shown that a one-megawatt, short-pulse source, which is an order of magnitude more powerful than LANSCE, could be built with today`s technology. In Europe, a preconceptual design study for a five-megawatt source is under way. Although such short-pulse sources are likely to be the wave of the future, they may not be necessary for some applications - such as Laue diffraction - which can be performed very well at a long-pulse spoliation source. Recently, it has been argued by Mezei that a facility that combines a short-pulse spallation source similar to LANSCE, with a one-megawatt, long-pulse spallation source would provide a cost-effective solution to the global shortage of neutrons for research. The basis for this assertion as well as the performance of some existing neutron spectrometers at short-pulse sources will be examined in this presentation.

  13. Neutron energy spectra of d(49)-Be and p(41)-Be neutron radiotherapy sources.

    Science.gov (United States)

    Graves, R G; Smathers, J B; Almond, P R; Grant, W H; Otte, V A

    1979-01-01

    Zero-degree neutron energy spectra for the p(41)-Be and d(49)-Be reactions were measured by time-of-flight for neutrons with energies above 1.9 and 1.4 MeV, respectively. Spectral changes resulting from the addition of copper, aluminum, and polyethylene filters to unfiltered beams were determined. Integral yields, average energies, filter material attenuation coefficients, and kerma fractions were computed for these spectra. Calculated spectra for neutron beams filtered by various thicknesses of polyethylene compared favorably with experimental results

  14. Modulating the Neutron Flux from a Mirror Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D D

    2011-09-01

    A 14-MeV neutron source based on a Gas-Dynamic Trap will provide a high flux of 14 MeV neutrons for fusion materials and sub-component testing. In addition to its main goal, the source has potential applications in condensed matter physics and biophysics. In this report, the author considers adding one more capability to the GDT-based neutron source, the modulation of the neutron flux with a desired frequency. The modulation may be an enabling tool for the assessment of the role of non-steady-state effects in fusion devices as well as for high-precision, low-signal basic science experiments favoring the use of the synchronous detection technique. A conclusion is drawn that modulation frequency of up to 1 kHz and modulation amplitude of a few percent is achievable. Limitations on the amplitude of modulations at higher frequencies are discussed.

  15. International workshop on cold neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; West, C.D. (comps.) (Los Alamos National Lab., NM (United States))

    1991-08-01

    The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources.

  16. Development of compact accelerator neutron source

    Directory of Open Access Journals (Sweden)

    Letourneau Alain

    2017-01-01

    Full Text Available There is a worldwide growing interest for small-scale and reduced-cost neutron sources not based on nuclear fission. High-intensity proton or deuteron beams impinging on light materials could be used to produce such neutron sources with intensities or brightness comparable to nuclear reactor for dedicated experiments. To develop such technologies several key technological issues have to be addressed. Among them the neutron production and the maximization of the neutron extraction and transport to the instrument is a key parameter for the design of high-brightness sources adapted for the required application. This issue have to be addressed with validated and predictive Monte-Carlo simulations. In this paper we present preliminary results on the use of Geant4 in the context of Compact Accelerator based Neutron Source (CANS developments.

  17. Fission-neutrons source with fast neutron-emission timing

    Energy Technology Data Exchange (ETDEWEB)

    Rusev, G., E-mail: rusev@lanl.gov; Baramsai, B.; Bond, E.M.; Jandel, M.

    2016-05-01

    A neutron source with fast timing has been built to help with detector-response measurements. The source is based on the neutron emission from the spontaneous fission of {sup 252}Cf. The time is provided by registering the fission fragments in a layer of a thin scintillation film with a signal rise time of 1 ns. The scintillation light output is measured by two silicon photomultipliers with rise time of 0.5 ns. Overall time resolution of the source is 0.3 ns. Design of the source and test measurements using it are described. An example application of the source for determining the neutron/gamma pulse-shape discrimination by a stilbene crystal is given.

  18. Unconventional neutron sources for oil well logging

    Energy Technology Data Exchange (ETDEWEB)

    Frankle, C.M., E-mail: cfrankle@lanl.gov; Dale, G.E.

    2013-09-21

    Americium–Beryllium (AmBe) radiological neutron sources have been widely used in the petroleum industry for well logging purposes. There is strong desire on the part of various governmental and regulatory bodies to find alternate sources due to the high activity and small size of AmBe sources. Other neutron sources are available, both radiological ({sup 252}Cf) and electronic accelerator driven (D–D and D–T). All of these, however, have substantially different neutron energy spectra from AmBe and thus cause significantly different responses in well logging tools. We report on simulations performed using unconventional sources and techniques to attempt to better replicate the porosity and carbon/oxygen ratio responses a well logging tool would see from AmBe neutrons. The AmBe response of these two types of tools is compared to the response from {sup 252}Cf, D–D, D–T, filtered D–T, and T–T sources. -- Highlights: • AmBe sources are widely used for well logging purposes. • Governmental bodies would prefer to minimize AmBe use. • Other neutron sources are available, both radiological and electronic. • Tritium–tritium spectrum neutrons have similar logging tool response to AmBe. • A tritium–tritium neutron generator may be a viable AmBe replacement.

  19. Doppler time-of-flight imaging

    KAUST Repository

    Heidrich, Wolfgang

    2017-02-16

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

  20. The accelerator neutron source for boron neutron capture therapy

    Science.gov (United States)

    Kasatov, D.; Koshkarev, A.; Kuznetsov, A.; Makarov, A.; Ostreinov, Yu; Shchudlo, I.; Sorokin, I.; Sycheva, T.; Taskaev, S.; Zaidi, L.

    2016-11-01

    The accelerator based epithermal neutron source for Boron Neutron Capture Therapy (BNCT) is proposed, created and used in the Budker Institute of Nuclear Physics. In 2014, with the support of the Russian Science Foundation created the BNCT laboratory for the purpose to the end of 2016 get the neutron flux, suitable for BNCT. For getting 3 mA 2.3 MeV proton beam, was created a new type accelerator - tandem accelerator with vacuum isolation. On this moment, we have a stationary proton beam with 2.3 MeV and current 1.75 mA. Generation of neutrons is carried out by dropping proton beam on to lithium target as a result of threshold reaction 7Li(p,n)7Be. Established facility is a unique scientific installation. It provides a generating of neutron flux, including a monochromatic energy neutrons, gamma radiation, alpha-particles and positrons, and may be used by other research groups for carrying out scientific researches. The article describes an accelerator neutron source, presents and discusses the result of experiments and declares future plans.

  1. Advanced Neutron Source (ANS) Project progress report

    Energy Technology Data Exchange (ETDEWEB)

    McBee, M.R.; Chance, C.M. (eds.) (Oak Ridge National Lab., TN (USA)); Selby, D.L.; Harrington, R.M.; Peretz, F.J. (Oak Ridge National Lab., TN (USA))

    1990-04-01

    This report discusses the following topics on the advanced neutron source: quality assurance (QA) program; reactor core development; fuel element specification; corrosion loop tests and analyses; thermal-hydraulic loop tests; reactor control concepts; critical and subcritical experiments; material data, structural tests, and analysis; cold source development; beam tube, guide, and instrument development; hot source development; neutron transport and shielding; I C research and development; facility concepts; design; and safety.

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

    OpenAIRE

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

    2011-01-01

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

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

    OpenAIRE

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

    2011-01-01

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

  4. Modeling a neutron rich nuclei source

    Energy Technology Data Exchange (ETDEWEB)

    Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J. [Institut de Physique Nucleaire, IN2P3/CNRS, 91 - Orsay (France); Mirea, M. [Institute of Physics and Nuclear Engineering, Tandem Lab., Bucharest (Romania)

    2000-07-01

    The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (author000.

  5. Novel Large Area High Resolution Neutron Detector for the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Jeffrey L

    2009-05-22

    Neutron scattering is a powerful technique that is critically important for materials science and structural biology applications. The knowledge gained from past developments has resulted in far-reaching advances in engineering, pharmaceutical and biotechnology industries, to name a few. New facilities for neutron generation at much higher flux, such as the SNS at Oak Ridge, TN, will greatly enhance the capabilities of neutron scattering, with benefits that extend to many fields and include, for example, development of improved drug therapies and materials that are stronger, longer-lasting, and more impact-resistant. In order to fully realize this enhanced potential, however, higher neutron rates must be met with improved detection capabilities, particularly higher count rate capability in large size detectors, while maintaining practicality. We have developed a neutron detector with the technical and economic advantages to accomplish this goal. This new detector has a large sensitive area, offers 3D spatial resolution, high sensitivity and high count rate capability, and it is economical and practical to produce. The proposed detector technology is based on B-10 thin film conversion of neutrons in long straw-like gas detectors. A stack of many such detectors, each 1 meter in length, and 4 mm in diameter, has a stopping power that exceeds that of He-3 gas, contained at practical pressures within an area detector. With simple electronic readout methods, straw detector arrays can provide spatial resolution of 4 mm FWHM or better, and since an array detector of such form consists of several thousand individual elements per square meter, count rates in a 1 m^2 detector can reach 2?10^7 cps. Moreover, each individual event can be timetagged with a time resolution of less than 0.1 ?sec, allowing accurate identification of neutron energy by time of flight. Considering basic elemental cost, this novel neutron imaging detector can be commercially produced economically

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  7. Investigation of Isfahan miniature neutron source reactor (MNSR) for boron neutron capture therapy by MCNP simulation

    OpenAIRE

    S. Z. Kalantari; H Tavakoli; Nami, M.

    2015-01-01

    One of the important neutron sources for Boron Neutron Capture Therapy (BNCT) is a nuclear reactor. It needs a high flux of epithermal neutrons. The optimum conditions of the neutron spectra for BNCT are provided by the International Atomic Energy Agency (IAEA). In this paper, Miniature Neutron Source Reactor (MNSR) as a neutron source for BNCT was investigated. For this purpose, we designed a Beam Shaping Assembly (BSA) for the reactor and the neutron transport from the core of the reactor t...

  8. High Brightness Neutron Source for Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, J. T.; Piestrup, Melvin, A.; Gary, Charles, K.; Harris, Jack, L. Williams, David, J.; Jones, Glenn, E.; Vainionpaa, J. , H.; Fuller, Michael, J.; Rothbart, George, H.; Kwan, J., W.; Ludewigt, B., A.; Gough, R.., A..; Reijonen, Jani; Leung, Ka-Ngo

    2008-12-08

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  9. An Accelerator Neutron Source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Thomas, E

    2006-03-14

    The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.

  10. Future opportunities with pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.D. [Rutherford Appleton Lab., Chilton (United Kingdom)

    1996-05-01

    ISIS is the world`s most powerful pulsed spallation source and in the past ten years has demonstrated the scientific potential of accelerator-driven pulsed neutron sources in fields as diverse as physics, earth sciences, chemistry, materials science, engineering and biology. The Japan Hadron Project gives the opportunity to build on this development and to further realize the potential of neutrons as a microscopic probe of the condensed state. (author)

  11. Performances of Neutron Scattering Spectrometers on a Compact Neutron Source

    CERN Document Server

    Fabrèges, Xavier; Ott, Frédéric; Chauvin, Nicolas; Schwindling, Jérôme; Letourneau, Alain; Marchix, Anthony

    2016-01-01

    There is currently a big effort put into the operation and construction of world class neutron scattering facilities (SNS and SNS-TS2 in the US, J-PARC in Japan, ESS in Europe, CSS in China, PIK in Russia). On the other hand, there exists a network of smaller neutron scattering facilities which play a key role in creating a large neutron scattering community who is able to efficiently use the existing facilities. With the foreseen closure of the ageing nuclear research reactors, especially in Europe there is a risk of seeing a shrinking of the community who would then be able to use efficiently the world class facilities. There is thus a reflection being conducted in several countries for the replacement of smaller research reactors with low energy accelerator based sources. We consider here a reference design for a compact neutron source based on existing accelerator components. We estimate the performances of various types of neutron scattering instruments built around such a source. The results suggest tha...

  12. Advances in time-of-flight PET.

    Science.gov (United States)

    Surti, Suleman; Karp, Joel S

    2016-01-01

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

  13. Advances in time-of-flight PET

    Science.gov (United States)

    Surti, Suleman; Karp, Joel S.

    2016-01-01

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

  14. Initial characterization of the Cornell Cold Neutron Source

    Science.gov (United States)

    Spern, Stuart Alan

    1998-06-01

    A device to moderate reactor spectrum neutrons to subthermal energies and filter out photons and higher energy neutrons has been designed, constructed and tested at Ward Laboratory, Cornell University. The Cornell Cold Neutron Source, which houses a chamber containing an organic moderator (mesitylene), the cryogenic cooling apparatus, and the first three one-meter long neutron guide elements, is physically inserted into a beamport in the reactor biological shield. The remaining 10 guide elements, which act as the filter, are mounted on a horizontal I-beam, and surrounded with suitable radiation shielding. The elements are horizontally displaced from the beamport axis in a combination curved/straight layout to eliminate directly transmitted radiation. The guide penetrates the reactor bay wall, terminating in a dedicated room to provide a location for low background experiments. Out-of-reactor bench thermal tests were conducted on the cryorefrigerator itself, then on a shortened version of the cryogenic cooling apparatus, and finally on the full scale system using heaters to simulate reactor induced nuclear heating in upstream cryogenic components. Temperature results, measured by silicon diodes, were close to predicted values. In-reactor tests were conducted to benchmark thermal performance, and to ascertain reliability of temperature and flux measurement systems. Type E thermocouples were selected for temperature measurement in the hostile reactor environment; although they depart from standard output at cryogenic temperatures due to inhomogeneities in the wire, crucial thermocouples located on the moderator chamber are calibrated against the in situ gas thermometer formed with the chamber as the sense bulb and a canister of known volume as the gas reservoir. In- reactor trials demonstrated reproducibility of thermocouple results. Moderator temperatures of 11 K at zero reactor power up to 28.5 K at 500 kW were obtained. Time-of-flight measurements were taken at 10

  15. Compact Neutron Sources for Energy and Security

    Science.gov (United States)

    Uesaka, Mitsuru; Kobayashi, Hitoshi

    We choose nuclear data and nuclear material inspection for energy application, and nondestructive testing of explosive and hidden nuclear materials for security application. Low energy (˜100keV) electrostatic accelerators of deuterium are commercially available for nondestructive testing. For nuclear data measurement, electrostatic ion accelerators and L-band (1.428GHz) and S-band (2.856GHz) electron linear accelerators (linacs) are used for the neutron source. Compact or mobile X-band (9.3, 11.424GHz) electron linac neutron sources are under development. A compact proton linac neutron source is used for nondestructive testing, especially water in solids. Several efforts for more neutron intensity using proton and deuteron accelerators are also introduced.

  16. Status of the Neutron Imaging and Diffraction Instrument IMAT

    Science.gov (United States)

    Kockelmann, Winfried; Burca, Genoveva; Kelleher, Joe F.; Kabra, Saurabh; Zhang, Shu-Yan; Rhodes, Nigel J.; Schooneveld, Erik M.; Sykora, Jeff; Pooley, Daniel E.; Nightingale, Jim B.; Aliotta, Francesco; Ponterio, Rosa C.; Salvato, Gabriele; Tresoldi, Dario; Vasi, Cirino; McPhate, Jason B.; Tremsin, Anton S.

    A cold neutron imaging and diffraction instrument, IMAT, is currently being constructed at the ISIS second target station. IMAT will capitalize on time-of-flight transmission and diffraction techniques available at a pulsed neutron source. Analytical techniques will include neutron radiography, neutron tomography, energy-selective neutron imaging, and spatially resolved diffraction scans for residual strain and texture determination. Commissioning of the instrument will start in 2015, with time-resolving imaging detectors and two diffraction detector prototype modules. IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

  17. Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

    CERN Document Server

    Matsumoto, T

    2003-01-01

    Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

  18. The Nanoscale Ordered MAterials Diffractometer NOMAD at the Spallation Neutron Source SNS

    Energy Technology Data Exchange (ETDEWEB)

    Feygenson, Mikhail [ORNL; Carruth, John William [ORNL; Hoffmann, Ron [ORNL; Chipley, Kenneth King [ORNL; Neuefeind, Joerg C [ORNL

    2012-01-01

    The Nanoscale Ordered Materials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair dist ribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals. Due to a large neutron flux provided by the Spallation Neutron Source SNS and a large detector coverage neutron count-rates exceed comparable instruments by one to two orders of magnitude. This is achieved while maintaining a relatively high momentum transfer resolution of a $\\delta Q/Q \\sim 0.8\\%$ FWHM (typical), and an achievable $\\delta Q/Q$ of 0.24\\% FWHM (best). The real space resolution is related to the maximum momentum transfer; A maximum momentum transfer of 50\\AA$^{-1}$ can be achieved routinely and the maximum momentum transfer given by the detector configuration and the incident neutron spectrum is 125 \\AA$^{-1}$. High stability of the source and the detector allow small contrast isotope experiments to be performed. A detailed description of the instrument is given and the results of experiments with standard samples are discussed.

  19. The Nanoscale Ordered MAterials Diffractometer NOMAD at the Spallation Neutron Source SNS

    Energy Technology Data Exchange (ETDEWEB)

    Neuefeind, Joerg, E-mail: neuefeindjc@ornl.gov [Neutron Scattering Science Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6475 (United States); Feygenson, Mikhail; Carruth, John; Hoffmann, Ron; Chipley, Kenneth K. [Neutron Scattering Science Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6475 (United States)

    2012-09-15

    The Nanoscale Ordered MAterials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair distribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals. Due to a large neutron flux provided by the Spallation Neutron Source SNS and a large detector coverage neutron count-rates exceed comparable instruments by one to two orders of magnitude. This is achieved while maintaining a relatively high momentum transfer resolution of a {delta}Q/Q{approx}0.8% FWHM (typical), and a possible {delta}Q/Qof0.24% FWHM (best). The real space resolution is related to the maximum momentum transfer; a maximum momentum transfer of 50 Angstrom-Sign {sup -1} can be obtained routinely and the maximum momentum transfer given by the detector configuration and the incident neutron spectrum is 125 Angstrom-Sign {sup -1}. High stability of the source and the detector allow small contrast isotope experiments to be performed. A detailed description of the instrument is given and the results of experiments with standard samples are discussed.

  20. The Nanoscale Ordered MAterials Diffractometer NOMAD at the Spallation Neutron Source SNS

    Science.gov (United States)

    Neuefeind, Jörg; Feygenson, Mikhail; Carruth, John; Hoffmann, Ron; Chipley, Kenneth K.

    2012-09-01

    The Nanoscale Ordered MAterials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair distribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals. Due to a large neutron flux provided by the Spallation Neutron Source SNS and a large detector coverage neutron count-rates exceed comparable instruments by one to two orders of magnitude. This is achieved while maintaining a relatively high momentum transfer resolution of a δQ/Q ˜0.8% FWHM (typical), and a possible δQ/Q of 0.24% FWHM (best). The real space resolution is related to the maximum momentum transfer; a maximum momentum transfer of 50 Å-1 can be obtained routinely and the maximum momentum transfer given by the detector configuration and the incident neutron spectrum is 125 Å. High stability of the source and the detector allow small contrast isotope experiments to be performed. A detailed description of the instrument is given and the results of experiments with standard samples are discussed.

  1. Iterative Reconstruction of Coded Source Neutron Radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Bingham, Philip R [ORNL; Gregor, Jens [University of Tennessee, Knoxville (UTK)

    2012-01-01

    Use of a coded source facilitates high-resolution neutron imaging but requires that the radiographic data be deconvolved. In this paper, we compare direct deconvolution with two different iterative algorithms, namely, one based on direct deconvolution embedded in an MLE-like framework and one based on a geometric model of the neutron beam and a least squares formulation of the inverse imaging problem.

  2. Concrete enclosure to shield a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Villagrana M, L. E.; Rivera P, E.; De Leon M, H. A.; Soto B, T. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: emmanuelvillagrana@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico)

    2012-10-15

    In the aim to design a shielding for a {sup 239}PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and the ambient dose equivalent were calculated at several distances ranging from 5 up to 150 cm, these calculations were repeated including air, and a 1 x 1 x 1 m{sup 3} enclosure that was shielded with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10{sup -8} up 0.5 MeV were the same regardless the distance from the source showing the room-return effect, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes -softer- as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated. (Author)

  3. 10 CFR 39.55 - Tritium neutron generator target sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in a...

  4. Iterative Reconstruction of Coded Source Neutron Radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Bingham, Philip R [ORNL; Gregor, Jens [University of Tennessee, Knoxville (UTK)

    2013-01-01

    Use of a coded source facilitates high-resolution neutron imaging through magnifications but requires that the radiographic data be deconvolved. A comparison of direct deconvolution with two different iterative algorithms has been performed. One iterative algorithm is based on a maximum likelihood estimation (MLE)-like framework and the second is based on a geometric model of the neutron beam within a least squares formulation of the inverse imaging problem. Simulated data for both uniform and Gaussian shaped source distributions was used for testing to understand the impact of non-uniformities present in neutron beam distributions on the reconstructed images. Results indicate that the model based reconstruction method will match resolution and improve on contrast over convolution methods in the presence of non-uniform sources. Additionally, the model based iterative algorithm provides direct calculation of quantitative transmission values while the convolution based methods must be normalized base on known values.

  5. Development of cold neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Oong; Cho, M. S.; Park, K. N. and others

    1999-05-01

    The purpose of this study is to develop the CNS facility in Hanaro to extend the scope of the neutron utilization and to carry out the works impossible by thermal neutrons. According to the project schedule, the establishment of the CNS concept and the basic design are performed in the phase 1, and the elementary technologies for basic design will be developed in the phase 2. Finally in the phase 3, the design of CNS will be completed, and the fabrication, the installation will be ended and then the development plan of spectrometers will be decided to establish the foothold to carry out the basic researches. This study is aimed to produce the design data and utilize them in the future basic and detail design, which include the estimation and the measurement of the heat load, the code development for the design of the in pile assembly and the heat removal system, the measurement of the shape of the CN hole, the performance test of thermosiphon and the concept of the general layout of the whole system etc.. (author)

  6. Pulse processing routines for neutron time-of-flight data

    CERN Document Server

    Žugec, P; Guerrero, C; Gunsing, F; Vlachoudis, V; Sabate-Gilarte, M; Stamatopoulos, A; Wright, T; Lerendegui-Marco, J; Mingrone, F; Ryan, J A; Warren, S G; Tsinganis, A; Barbagallo, M

    2016-01-01

    A pulse shape analysis framework is described, which was developed for n_TOF-Phase3, the third phase in the operation of the n_TOF facility at CERN. The most notable feature of this new framework is the adoption of generic pulse shape analysis routines, characterized by a minimal number of explicit assumptions about the nature of pulses. The aim of these routines is to be applicable to a wide variety of detectors, thus facilitating the introduction of the new detectors or types of detectors into the analysis framework. The operational details of the routines are suited to the specific requirements of particular detectors by adjusting the set of external input parameters. Pulse recognition, baseline calculation and the pulse shape fitting procedure are described. Special emphasis is put on their computational efficiency, since the most basic implementations of these conceptually simple methods are often computationally inefficient.

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

    Science.gov (United States)

    Schwarz, Sebastian; Sjostrom, Marten; Olsson, Roger

    2014-01-01

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

  8. Sweden to host a new neutron source

    CERN Document Server

    Anaïs Schaeffer

    2012-01-01

    The first European neutron source, currently under development, should commence operations by the end of this decade. Its aim: to produce beams of neutrons that can penetrate into the heart of matter without damaging it and reveal its secrets.   An artist's impression of what the ESS should look like in 2019. At the southern end of Sweden, a town called Lund is preparing for the arrival of the world's most powerful neutron source: the European Spallation Source (ESS). Construction is scheduled to start at the beginning of next year, and the facility is expected to become operational by 2019, when it will produce its first neutron beams. “The ESS is the result of an idea that began 20 years ago!” underlines Mats Lindroos, in charge of the ESS Accelerator Division. “Today, 17 European countries support the project, including Sweden, Denmark and Norway, who together account for 50% of the construction funding.” The ESS, whose design is al...

  9. Neutron energy spectra of sup 2 sup 5 sup 2 Cf, Am-Be source and of the D(d,n) sup 3 He reaction

    CERN Document Server

    Sang Tae Park

    2003-01-01

    The neutron energy spectrum of the following sources were measured using a fast neutron spectrometer with the NE-213 liquid scintillator: sup 2 sup 5 sup 2 Cf, Am-Be and D(d,n) sup 3 He reaction from a 3 MeV Pelletron accelerator in Tokyo Institute of Technology. The measured proton recoil pulse height data of sup 2 sup 5 sup 2 Cf, Am-Be and D(d,n) sup 3 He were unfolded using the mathematical program to obtain the neutron energy spectrum. The sup 2 sup 5 sup 2 Cf and Am-Be neutron energy spectra were measured and the results obtained showed a good agreement with the spectra usually published in the literature. The neutron energy spectrum from D(d,n) sup 3 He was measured and the results obtained also showed a good agreement with the calculation by time of flight (TOF) methods. (author)

  10. Material selection for spallation neutron source windows

    Energy Technology Data Exchange (ETDEWEB)

    Sordo, F. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain); Abanades, A. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain)], E-mail: abanades@etsii.upm.es; Lafuente, A.; Martinez-Val, J.M. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain); Perlado, M. [Instituto de Fusion Nuclear (DENIM)/ETSII/Universidad Politecnica, Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain)

    2009-11-15

    High performance neutron sources are being proposed for many scientific and industrial applications, ranging from material studies, hybrid reactors and transmutation of nuclear wastes. In the case of transmutation of nuclear wastes, accelerator driven systems (ADS) are considered as one of the main technical options for such purpose. In ADS a high performance spallation neutron source becomes an essential element for its operation and control. This spallation source must fulfil very challenging nuclear and thermo-mechanical requirements, because of the high neutron rates needed in ADS. The material selection for this key component becomes of paramount importance, particularly the source window that separates the vacuum accelerator tube from the spallation material where the accelerated protons impinge. In this paper, an integral analysis of spallation sources is done, taking as a reference the projects in this field proposal in the framework of European projects. Our analysis and calculations show that titanium and vanadium alloys are more suitable than steel as structural material for an industrial ADS beam window, mostly due to its irradiation damage resistance.

  11. Calibration of an EJ309 liquid scintillator using an AmBe neutron source

    Science.gov (United States)

    Bai, Huaiyong; Wang, Zhimin; Zhang, Luyu; Lu, Yi; Jiang, Haoyu; Chen, Jinxiang; Zhang, Guohui

    2017-08-01

    As the light output function of the EJ309 liquid scintillator is nonlinear with respect to the energy of the recoil proton and it is difficult to be predicted, it need to be measured. In the present work, an EJ309 liquid scintillator, 5.1 cm in diameter and 5.1 cm in length, is calibrated with an AmBe neutron source using the time-of-flight method. A Monte Carlo simulation is performed to improve the accuracy of the measured light output function. The obtained light output function is presented and it is compared with existing measurements. The energy resolution of the EJ309 Liquid scintillator is also illustrated.

  12. Synchrotron based spallation neutron source concepts

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.

    1998-07-01

    During the past 20 years, rapid-cycling synchrotrons (RCS) have been used very productively to generate short-pulse thermal neutron beams for neutron scattering research by materials science communities in Japan (KENS), the UK (ISIS) and the US (IPNS). The most powerful source in existence, ISIS in the UK, delivers a 160-kW proton beam to a neutron-generating target. Several recently proposed facilities require proton beams in the MW range to produce intense short-pulse neutron beams. In some proposals, a linear accelerator provides the beam power and an accumulator ring compresses the pulse length to the required {approx} 1 {micro}s. In others, RCS technology provides the bulk of the beam power and compresses the pulse length. Some synchrotron-based proposals achieve the desired beam power by combining two or more synchrotrons of the same energy, and others propose a combination of lower and higher energy synchrotrons. This paper presents the rationale for using RCS technology, and a discussion of the advantages and disadvantages of synchrotron-based spallation sources.

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

    DEFF Research Database (Denmark)

    Zhou, Weiguo; Lyu, Congyi; Jiang, Xin

    2017-01-01

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

  14. Low dimensional neutron moderators for enhanced source brightness

    DEFF Research Database (Denmark)

    Mezei, Ferenc; Zanini, Luca; Takibayev, Alan;

    2014-01-01

    In a recent numerical optimization study we have found that liquid para-hydrogen coupled cold neutron moderators deliver 3–5 times higher cold neutron brightness at a spallation neutron source if they take the form of a flat, quasi 2-dimensional disc, in contrast to the conventional more voluminous...... for cold neutrons. This model leads to the conclusions that the optimal shape for high brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and these low dimensional moderators can also deliver much enhanced cold neutron brightness in fission reactor neutron sources, compared...

  15. INJECTION CHOICE FOR SPALLATION NEUTRON SOURCE RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; BRODOWSKI,J.; FEDOTOV,A.; GARDNER,C.; LEE,Y.Y.; RAPARIA,D.; DANILOV,V.; HOLMES,J.; PRIOR,C.; REES,G.; MACHIDA,S.

    2001-06-18

    Injection is key in the low-loss design of high-intensity proton facilities like the Spallation Neutron Source (SNS). During the design of both the accumulator and the rapid-cycling-synchrotron version of the SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's low-loss design criteria. This paper presents issues and considerations pertaining to the final choice of the SNS injection systems.

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

    Science.gov (United States)

    Mikkelson, D.; Worlton, T.

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

  17. Linac-driven spallation-neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Jason, A.J.

    1995-05-01

    Strong interest has arisen in accelerator-driven spallation-neutron sources that surpass existing facilities (such as ISIS at Rutherford or LANSCE at Los Alamos) by more than an order of magnitude in beam power delivered to the spallation target. The approach chosen by Los Alamos (as well as the European Spallation Source) provides the full beam energy by acceleration in a linac as opposed to primary acceleration in a synchrotron or other circular device. Two modes of neutron production are visualized for the source. A short-pulse mode produces 1 MW of beam power (at 60 pps) in pulses, of length less than 1 ms, by compression of the linac macropulse through multi-turn injection in an accumulator ring. A long-pulse mode produces a similar beam power with 1-ms-long pulses directly applied to a target. This latter mode rivals the performance of existing reactor facilities to very low neutron energies. Combination with the short-pulse mode addresses virtually all applications.

  18. The spallation neutron source: New opportunities

    Indian Academy of Sciences (India)

    Ian S Anderson

    2008-11-01

    The spallation neutron source (SNS) facility became operational in the spring of 2006, and is now well on its way to become the world-leading facility for neutron scattering. Furthermore, the SNS and the HFIR reactor facility, newly outfitted with a brilliant cold source and guide hall, were brought together within a single Neutron Sciences Directorate at ORNL providing the opportunity to develop science and instrumentation programs which take advantage of the unique characteristics of each source. SNS and HFIR will both operate as scientific user facilities. Access to these facilities is being managed under an integrated proposal system, which also includes the Center for Nanophase Materials Sciences (CNMS) and the electron microscopes in the Shared Research Equipment (SHARE) program. Presently, SNS has three instruments operating in the user program and seven more will begin operations in 2008. When complete, the facility will accommodate 25 instruments enabling researchers from the United States and abroad to study materials science that forms the basis for new technologies in telecommunications, manufacturing, transportation, information technology, biotechnology, and health.

  19. Neutron proton crystallography station (PCS)

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Zoe [Los Alamos National Laboratory; Kovalevsky, Andrey [Los Alamos National Laboratory; Johnson, Hannah [Los Alamos National Laboratory; Mustyakimov, Marat [Los Alamos National Laboratory

    2009-01-01

    The PCS (Protein Crystallography Station) at Los Alamos Neutron Science Center (LANSCE) is a unique facility in the USA that is designed and optimized for detecting and collecting neutron diffraction data from macromolecular crystals. PCS utilizes the 20 Hz spallation neutron source at LANSCE to enable time-of-flight measurements using 0.6-7.0 {angstrom} neutrons. This increases the neutron flux on the sample by using a wavelength range that is optimal for studying macromolecular crystal structures. The diagram below show a schematic of PCS and photos of the detector and instrument cave.

  20. Mixed clusters from the coexpansion of C2F6 and n2 in a pulsed, supersonic expansion cluster ion source and beam deflection time-of-flight mass spectrometer: A first application

    Science.gov (United States)

    Thompson, Steven D.

    The following topics are discussed: (1) cluster ion genesis; (2) cluster ion detection; (3) Ion source; (4) pulse valve; (5) e-gun; (6) Ion optics; (7) a first order model; and (8) a modified Bakker's model.

  1. Neutron Source from Laser Plasma Acceleration

    Science.gov (United States)

    Jiao, Xuejing; Shaw, Joseph; McCary, Eddie; Downer, Mike; Hegelich, Bjorn

    2016-10-01

    Laser driven electron beams and ion beams were utilized to produce neutron sources via different mechanism. On the Texas Petawatt laser, deuterized plastic, gold and DLC foil targets of varying thickness were shot with 150 J , 150 fs laser pulses at a peak intensity of 2 ×1021W /cm2 . Ions were accelerated by either target normal sheath acceleration or Breakout Afterburner acceleration. Neutrons were produced via the 9Be(d,n) and 9Be(p,n) reactions when accelerated ions impinged on a Beryllium converter as well as by deuteron breakup reactions. We observed 2 ×1010 neutron per shot in average, corresponding to 5 ×1018n /s . The efficiencies for different targets are comparable. In another experiment, 38fs , 0.3 J UT3 laser pulse interacted with mixed gas target. Electrons with energy 40MeV were produced via laser wakefield acceleration. Neutron flux of 2 ×106 per shot was generated through bremsstrahlung and subsequent photoneutron reactions on a Copper converter.

  2. Advanced Neutron Source: Plant Design Requirements

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

  3. Advanced Neutron Source: Plant Design Requirements

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

  4. Spallation neutron source and other high intensity froton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  5. Neutron diffractometers for structural biology at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Schoenborn, B.P.; Pitcher, E. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Spallation neutron sources are ideal for diffraction studies of proteins and oriented molecular complexes. With spoliation neutrons and their time dependent wavelength structure, it is easy to electronically select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved snapshots. This optimized data quality with best peak-to-background ratios and provides adequate spatial and energy resolution to eliminate peak overlaps. The application of this concept will use choppers to select the desired Laue wavelength spectrum and employ focusing optics and large cylindrical {sup 3}He detectors to optimize data collection rates. Such a diffractometer will cover a Laue wavelength range from 1 to 5{Angstrom} with a flight path length of 10m and an energy resolution of 0.25{Angstrom}. Moderator concepts for maximal flux distribution within this energy range will be discussed using calculated flux profiles. Since the energy resolution required for such timed data collection in this super Laue techniques is not very high, the use of a linac only (LAMPF) spoliation target is an exciting possibility with an order of magnitude increase in flux.

  6. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    Science.gov (United States)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  7. Overview of the conceptual design of the future VENUS beamline at the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Bilheux, Hassina Z [ORNL; Herwig, Kenneth W [ORNL; Keener, Wylie S [ORNL; Davis, Larry E [ORNL

    2015-01-01

    VENUS will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to m). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beamline 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS

  8. New sources and instrumentation for neutrons in biology

    DEFF Research Database (Denmark)

    Teixeira, S. C. M.; Zaccai, G.; Ankner, J.

    2008-01-01

    Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.......Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed....

  9. New sources and instrumentation for neutrons in biology

    DEFF Research Database (Denmark)

    Teixeira, S. C. M.; Zaccai, G.; Ankner, J.;

    2008-01-01

    Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.......Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed....

  10. Using MCNP in the design of neutron sources and neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Hergenreder, Daniel F.; Lecot, Carlos A.; Lovotti, Osvaldo P. [INVAP S.A., San Carlos de Bariloche (Argentina). Nuclear Projects Department. Nuclear Engineering Division

    2002-07-01

    The calculation methodology used to design cold, thermal and hot neutron sources and their associated neutron beam transport systems is presented. The design goal is to evaluate the performance of the neutron sources, their beam tubes and neutron guides at specific experimental locations in the reactor hall as well as in the neutron hall. The Monte Carlo method is a unique and powerful tool to transport neutrons. Its use in a bootstrap scheme appears to be an appropriate solution for this type of system. The proper use of MCNP as the main tool leads to a fast and reliable method to perform calculations in a relatively short time with low statistical errors. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-06-07

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

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

    Science.gov (United States)

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

    2008-06-01

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

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

    Science.gov (United States)

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

    2008-06-07

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

  14. Physics and technology of spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.

    1998-08-01

    Next to fission and fusion, spallation is an efficient process for releasing neutrons from nuclei. Unlike the other two reactions, it is an endothermal process and can, therefore, not be used per se in energy generation. In order to sustain a spallation reaction, an energetic beam of particles, most commonly protons, must be supplied onto a heavy target. Spallation can, however, play an important role as a source of neutrons whose flux can be easily controlled via the driving beam. Up to a few GeV of energy, the neutron production is roughly proportional to the beam power. Although sophisticated Monte Carlo codes exist to compute all aspects of a spallation facility, many features can be understood on the basis of simple physics arguments. Technically a spallation facility is very demanding, not only because a reliable and economic accelerator of high power is needed to drive the reaction, but also, and in particular, because high levels of radiation and heat are generated in the target which are difficult to cope with. Radiation effects in a spallation environment are different from those commonly encountered in a reactor and are probably even more temperature dependent than the latter because of the high gas production rate. A commonly favored solution is the use of molten heavy metal targets. While radiation damage is not a problem in this case, except for the container, a number of other issues are discussed. (author)

  15. Detection, identification, and occurrence of thiotetronic acids in drinking water from underground sources by electrospray ionization-high field asymmetric waveform ion mobility spectrometry-quadrupole time-of-flight-mass spectrometry.

    Science.gov (United States)

    Lyczko, Jadwiga; Beach, Daniel; Gabryelski, Wojciech

    2015-10-01

    This paper demonstrates that electrospray ionization (ESI) with differential ion mobility spectroscopy (FAIMS) and "soft" mass spectrometry (MS) provide unique analytical capabilities that led to the discovery of sulfur-containing polar congeners of thiotetronic acid (TA) in drinking water from underground sources in Canada and the United States. Polar TAs accumulate in underground aquifers and appear to be the most abundant class of organic compounds in bottled water but cannot be detected by conventional mass spectrometry methods. We show that normally stable TAs are converted into very reactive ions in ESI which have to be analyzed using special conditions in ESI-FAIMS-MS to avoid extensive dissociation and ion/molecule reactions. De novo identification of 10 TAs was accomplished by the comparative tandem mass spectrometry analysis of authentic TA derivatives from groundwater samples and synthetic TA analogues prepared for this study. We present highlights of gas phase ion chemistry of polar TAs to explain their unique properties and reactivity. TA derivatives were originally isolated from soil bacteria and are of interest in the pharmaceutical industry due to their potent activity against a broad spectrum of pathogenic bacteria and negligible toxicity to mammals. We suspect that TAs are natural disinfection agents protecting groundwater from bacterial contamination, but these compound undergo modifications or decompose during an ozonation water treatment.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-12-31

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

  17. ALICE EXPERIMENT Time of Flight Multigap Resistive Plate Chambers

    CERN Multimedia

    2003-01-01

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

  18. Time-of-flight imaging of invisibility cloaks

    CERN Document Server

    Halimeh, Jad C

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-12-31

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

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

    NARCIS (Netherlands)

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

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

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

    Energy Technology Data Exchange (ETDEWEB)

    S. Majewski; A. Margaryan; L. Tang

    2005-08-05

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

  2. Field ion source development for neutron generators

    Science.gov (United States)

    Bargsten Johnson, B.; Schwoebel, P. R.; Holland, C. E.; Resnick, P. J.; Hertz, K. L.; Chichester, D. L.

    2012-01-01

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption (˜20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with ˜10,000 tip arrays have achieved deuterium ion currents of ˜50 nA. Neutron production by field ionization has yielded ˜10 2 n/s from ˜1 mm 2 of array area using the deuterium-deuterium fusion reaction at 90 kV.

  3. Field ion source development for neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Bargsten Johnson, B. [University of New Mexico, Albuquerque, NM 87131 (United States); Schwoebel, P.R., E-mail: schwoebel@chtm.unm.edu [University of New Mexico, Albuquerque, NM 87131 (United States); Holland, C.E. [SRI International, Menlo Park, CA 94025 (United States); Resnick, P.J. [Sandia National Laboratories, Albuquerque, NM 87123 (United States); Hertz, K.L. [Sandia National Laboratories, Livermore, CA 94551 (United States); Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2012-01-21

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

  4. Field Ion Source Development for Neutron Generators

    Energy Technology Data Exchange (ETDEWEB)

    B. Bargsten Johnson; P. R. Schwoebel; C. E. Holland; P. J. Resnick; K. L. Hertz; D. L. Chichester

    2012-01-01

    An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

  5. European Spallation Source and Neutron Science

    Science.gov (United States)

    Yeck, James

    2014-03-01

    International collaborations in large-scale scientific projects can link Sciences and Society. Following this goal, the European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries. Scandinavia is providing 50 percent of the construction cost whilst the other member states are providing financial support mainly via in-kind contribution from institutes, laboratories or industries of the given countries. Scientists and engineers from 35 different countries are members of the workforce in Lund who participate in its design and construction. The ESS will enable new opportunities for researchers in fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics by producing very high flux neutrons to study condensed matter physics, chemistry, biology, nuclear physics and materials science. The ESS will be up to 30 times brighter than today's leading facilities and neutron sources. A tungsten target and a 5 MW long pulse proton accelerator, composed mainly of superconducting Radio-Frequency components, are used to achieve these goals.

  6. Fission, spallation or fusion-based neutron sources

    Indian Academy of Sciences (India)

    Kurt N Clausen

    2008-10-01

    In this paper the most promising technology for high power neutron sources is briefly discussed. The conclusion is that the route to high power neutron sources in the foreseeable future is spallation – short or long pulse or even CW – all of these sources will have areas in which they excel.

  7. A capture-gated neutron spectrometer for characterization of neutron sources and their shields

    Energy Technology Data Exchange (ETDEWEB)

    Holm, Philip, E-mail: philip.holm@stuk.fi; Peräjärvi, Kari; Ristkari, Samu; Siiskonen, Teemu; Toivonen, Harri

    2014-07-01

    A portable capture-gated neutron spectrometer was designed and built. The spectrometer consists of a boron-loaded scintillator. Data acquisition is performed in list-mode. {sup 252}Cf and AmBe sources and various neutron and gamma shields were used to characterize the response of the device. It is shown that both the unfolded capture-gated neutron spectrum and the singles spectrum up to 5 MeV should be utilized. Source identification is then possible and important information is revealed regarding the surroundings of the source. The detector's discrimination of neutrons from photons is relatively good; specifically, one out of 10{sup 5} photons is misclassified as a neutron and, more importantly, this misclassification rate can be calculated precisely for different measurement environments and can be taken into account in setting alarm limits for neutron detection. The source and source shield identification capabilities of the detector make it an interesting asset for security applications.

  8. UCN Source at an External Beam of Thermal Neutrons

    Directory of Open Access Journals (Sweden)

    E. V. Lychagin

    2015-01-01

    Full Text Available We propose a new method for production of ultracold neutrons (UCNs in superfluid helium. The principal idea consists in installing a helium UCN source into an external beam of thermal or cold neutrons and in surrounding this source with a solid methane moderator/reflector cooled down to ~4 K. The moderator plays the role of an external source of cold neutrons needed to produce UCNs. The flux of accumulated neutrons could exceed the flux of incident neutrons due to their numerous reflections from methane; also the source size could be significantly larger than the incident beam diameter. We provide preliminary calculations of cooling of neutrons. These calculations show that such a source being installed at an intense source of thermal or cold neutrons like the ILL or PIK reactor or the ESS spallation source could provide the UCN density 105 cm−3, the production rate 107 UCN/s−1. Main advantages of such an UCN source include its low radiative and thermal load, relatively low cost, and convenient accessibility for any maintenance. We have carried out an experiment on cooling of thermal neutrons in a methane cavity. The data confirm the results of our calculations of the spectrum and flux of neutrons in the methane cavity.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-12-11

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

  10. The Spallation Neutron Source accelerator system design

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, S., E-mail: stuarth@fnal.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Abraham, W. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Aleksandrov, A. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Allen, C. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Alonso, J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Anderson, D. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Arenius, D. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Arthur, T. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Assadi, S. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Ayers, J.; Bach, P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Badea, V. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Battle, R. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Beebe-Wang, J. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); and others

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ∼100 high-power RF power systems, a 2 K cryogenic plant, ∼400 DC and pulsed power supply systems, ∼400 beam diagnostic devices and a distributed control system handling ∼100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  11. The Spallation Neutron Source accelerator system design

    Science.gov (United States)

    Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  12. Cryogenic System for the Spallation Neutron Source

    Science.gov (United States)

    Arenius, D.; Chronis, W.; Creel, J.; Dixon, K.; Ganni, V.; Knudsen, P.

    2004-06-01

    The Spallation Neutron Source (SNS) is a neutron-scattering facility being built at Oak Ridge, TN for the US Department of Energy. The SNS accelerator linac consists of superconducting radio-frequency (SRF) cavities in cryostats (cryomodules). The linac cryomodules are cooled to 2.1 K by a 2300 watt cryogenic refrigeration system. As an SNS partner laboratory, Jefferson Lab is responsible for the installed integrated cryogenic system design for the SNS linac accelerator consisting of major subsystem equipment engineered and procured from industry. Jefferson Lab's work included developing the major vendor subsystem equipment procurement specifications, equipment procurement, and the integrated system engineering support of the field installation and commissioning. The major cryogenic system components include liquid nitrogen storage, gaseous helium storage, cryogen distribution transfer line system, 2.1-K cold box consisting of four stages of cold compressors, 4.5-K cold box, warm helium compressors with its associated oil removal, gas management, helium purification, gas impurity monitoring systems, and the supportive utilities of electrical power, cooling water and instrument air. The system overview, project organization, the important aspects, and the capabilities of the cryogenic system are described.

  13. PREFACE: Neutrino physics at spallation neutron sources

    Science.gov (United States)

    Avignone, F. T.; Chatterjee, L.; Efremenko, Y. V.; Strayer, M.

    2003-11-01

    Unique because of their super-light masses and tiny interaction cross sections, neutrinos combine fundamental physics on the scale of the miniscule with macroscopic physics on the scale of the cosmos. Starting from the ignition of the primal p-p chain of stellar and solar fusion reactions that signal star-birth, these elementary leptons (neutrinos) are also critical players in the life-cycles and explosive deaths of massive stars and the production and disbursement of heavy elements. Stepping beyond their importance in solar, stellar and supernova astrophysics, neutrino interactions and properties influence the evolution, dynamics and symmetries of the cosmos as a whole. Further, they serve as valuable probes of its material content at various levels of structure from atoms and nuclei to valence and sea quarks. In the light of the multitude of physics phenomena that neutrinos influence, it is imperative to enhance our understanding of neutrino interactions and properties to the maximum. This is accentuated by the recent evidence of finite neutrino mass and flavour mixing between generations that reverberates on the plethora of physics that neutrinos influence. Laboratory experiments using intense neutrino fluxes would allow precision measurements and determination of important neutrino reaction rates. These can then complement atmospheric, solar and reactor experiments that have enriched so valuably our understanding of the neutrino and its repertoire of physics applications. In particular, intermediate energy neutrino experiments can provide critical information on stellar and solar astrophysical processes, along with advancing our knowledge of nuclear structure, sub-nuclear physics and fundamental symmetries. So where should we look for such intense neutrino sources? Spallation neutron facilities by their design are sources of intense neutrino pulses that are produced as a by-product of neutron spallation. These neutrino sources could serve as unique laboratories

  14. Studies and modeling of cold neutron sources; Etude et modelisation des sources froides de neutron

    Energy Technology Data Exchange (ETDEWEB)

    Campioni, G

    2004-11-15

    With the purpose of updating knowledge in the fields of cold neutron sources, the work of this thesis has been run according to the 3 following axes. First, the gathering of specific information forming the materials of this work. This set of knowledge covers the following fields: cold neutron, cross-sections for the different cold moderators, flux slowing down, different measurements of the cold flux and finally, issues in the thermal analysis of the problem. Secondly, the study and development of suitable computation tools. After an analysis of the problem, several tools have been planed, implemented and tested in the 3-dimensional radiation transport code Tripoli-4. In particular, a module of uncoupling, integrated in the official version of Tripoli-4, can perform Monte-Carlo parametric studies with a spare factor of Cpu time fetching 50 times. A module of coupling, simulating neutron guides, has also been developed and implemented in the Monte-Carlo code McStas. Thirdly, achieving a complete study for the validation of the installed calculation chain. These studies focus on 3 cold sources currently functioning: SP1 from Orphee reactor and 2 other sources (SFH and SFV) from the HFR at the Laue Langevin Institute. These studies give examples of problems and methods for the design of future cold sources.

  15. Spectrometry and dosimetry of a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Ramirez G, J.; Hernandez V, R.; Chacon R, A. [Universidad Autonoma de Zacatecas, 98068 Zacatecas (Mexico)]. e-mail: fermineutron@yahoo.com

    2007-07-01

    Using Monte Carlo methods the spectrum, dose equivalent and ambient dose equivalent of a {sup 239}PuBe at several distances has been determined. Spectrum and both doses, at 100 cm, were determined-experimentally using a Bonner sphere spectrometer. These quantities were obtained by unfolding the spectrometer count rates using artificial neural networks. The dose equivalent, based in the ICRP 21 criteria, was measured with the area neutron dosemeter Eberline model NRI), at 100, 200 and 300 cm. All measurements were carried out in an open space to avoid the room return. With these results it was found that this source has a yield of 8.41E(6) n/s. (Author)

  16. Electronic neutron sources for compensated porosity well logging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A. X.; Antolak, A. J.; Leung, K. -N.

    2012-08-01

    The viability of replacing Americium–Beryllium (Am–Be) radiological neutron sources in compensated porosity nuclear well logging tools with D–T or D–D accelerator-driven neutron sources is explored. The analysis consisted of developing a model for a typical well-logging borehole configuration and computing the helium-3 detector response to varying formation porosities using three different neutron sources (Am–Be, D–D, and D–T). The results indicate that, when normalized to the same source intensity, the use of a D–D neutron source has greater sensitivity for measuring the formation porosity than either an Am–Be or D–T source. The results of the study provide operational requirements that enable compensated porosity well logging with a compact, low power D–D neutron generator, which the current state-of-the-art indicates is technically achievable.

  17. Electronic neutron sources for compensated porosity well logging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A.X., E-mail: axchen@sandia.gov [Sandia National Laboratories, Livermore, CA 94550 (United States); Antolak, A.J.; Leung, K.-N. [Sandia National Laboratories, Livermore, CA 94550 (United States)

    2012-08-21

    The viability of replacing Americium-Beryllium (Am-Be) radiological neutron sources in compensated porosity nuclear well logging tools with D-T or D-D accelerator-driven neutron sources is explored. The analysis consisted of developing a model for a typical well-logging borehole configuration and computing the helium-3 detector response to varying formation porosities using three different neutron sources (Am-Be, D-D, and D-T). The results indicate that, when normalized to the same source intensity, the use of a D-D neutron source has greater sensitivity for measuring the formation porosity than either an Am-Be or D-T source. The results of the study provide operational requirements that enable compensated porosity well logging with a compact, low power D-D neutron generator, which the current state-of-the-art indicates is technically achievable.

  18. Neutron activation analysis: Modelling studies to improve the neutron flux of Americium-Beryllium source

    Energy Technology Data Exchange (ETDEWEB)

    Didi, Abdessamad; Dadouch, Ahmed; Tajmouati, Jaouad; Bekkouri, Hassane [Advanced Technology and Integration System, Dept. of Physics, Faculty of Science Dhar Mehraz, University Sidi Mohamed Ben Abdellah, Fez (Morocco); Jai, Otman [Laboratory of Radiation and Nuclear Systems, Dept. of Physics, Faculty of Sciences, Tetouan (Morocco)

    2017-06-15

    Americium–beryllium (Am-Be; n, γ) is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences. It is a mobile source of neutron activity (20 Ci), yielding a small thermal neutron flux that is water moderated. The aim of this study is to develop a model to increase the neutron thermal flux of a source such as Am-Be. This study achieved multiple advantageous results: primarily, it will help us perform neutron activation analysis. Next, it will give us the opportunity to produce radio-elements with short half-lives. Am-Be single and multisource (5 sources) experiments were performed within an irradiation facility with a paraffin moderator. The resulting models mainly increase the thermal neutron flux compared to the traditional method with water moderator.

  19. The ANTARES recoil time-of-flight spectrometer

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

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

    KAUST Repository

    Shrestha, Shikhar

    2016-07-11

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-31

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

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

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

    CERN Document Server

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

    2002-01-01

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

  4. Neutron calibration sources in the Daya Bay experiment

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J., E-mail: jianglai.liu@sjtu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Carr, R. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Dwyer, D.A. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gu, W.Q. [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Li, G.S., E-mail: lgs1029@sjtu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); McKeown, R.D. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Department of Physics, College of William and Mary, Williamsburg, VA (United States); Qian, X. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Brookhaven National Laboratory, Upton, NY (United States); Tsang, R.H.M. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Wu, F.F. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Zhang, C. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Brookhaven National Laboratory, Upton, NY (United States)

    2015-10-11

    We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. The design characteristics have been validated in the Daya Bay anti-neutrino detector.

  5. Neutron Calibration Sources in the Daya Bay Experiment

    CERN Document Server

    Liu, J; Dwyer, D A; Gu, W Q; Li, G S; McKeown, R D; Qian, X; Tsang, R H M; Wu, F F; Zhang, C

    2015-01-01

    We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. The design characteristics have been validated in the Daya Bay anti-neutrino detector.

  6. Nondiffractive applications of neutrons at the spallation source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    The paper delivers an overview about experiments with neutrons from the spallation source SINQ which are not especially devoted to neutron scattering. A total of six experimental facilities are under construction using thermal as well as cold neutrons. Starting with some general considerations about the interaction of neutrons with matter, the principles, boundary conditions and the experimental set up of these experiments are described briefly. Some more details are given for the neutron radiography facility NEUTRA as the author`s special interest and research field. (author) 7 figs., 2 tabs., 9 refs.

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

    CERN Document Server

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

    2014-01-01

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

  8. Continuous time of flight measurements in a Lissajous configuration

    Science.gov (United States)

    Dobos, G.; Hárs, G.

    2017-01-01

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

  9. New Techniques in Neutron Scattering

    DEFF Research Database (Denmark)

    Birk, Jonas Okkels

    Neutron scattering is an important experimental technique in amongst others solid state physics, biophysics, and engineering. This year construction of European Spallation Source (ESS) was commenced in Lund, Sweeden. The facility will use a new long pulsed source principle to obtain higher...... potential performance than any existing facility, however in order to use this pulse structure optimally many existing neutron scattering instruments will need to be redesigned. This defense will concentrate on the design and optimization of the inverse time-of-flight cold neutron spectrometer CAMEA...

  10. Extracting source parameters from beam monitors on a chopper spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Abernathy, Douglas L [ORNL; Niedziela, Jennifer L [ORNL; Stone, Matthew B [ORNL

    2015-01-01

    The intensity distributions of beam monitors in direct-geometry time-of-flight neutron spectrometers provide important information about the instrument resolution. For short-pulse spallation neutron sources in particular, the asymmetry of the source pulse may be extracted and compared to Monte Carlo source simulations. An explicit formula using a Gaussian-convolved Ikeda-Carpenter distribution is given and compared to data from the ARCS instrument at the Spallation Neutron Source.

  11. Monte-Carlo simulations of elastically backscattered neutrons from hidden explosives using three different neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    ElAgib, I. [College of Science, King Saud University, P.O. Box 2455 (Saudi Arabia)], E-mail: elagib@ksu.edu.sa; Elsheikh, N. [College of Applied and Industrial Science, University of Juba, Khartoum, P.O. Box 321 (Sudan); AlSewaidan, H. [College of Science, King Saud University, P.O. Box 2455 (Saudi Arabia); Habbani, F. [Faculty of Science, Physics Department, University of Khartoum, Khartoum, P.O. Box 321 (Sudan)

    2009-01-15

    Calculations of elastically backscattered (EBS) neutrons from hidden explosives buried in soil were performed using Monte-Carlo N-particle transport code MCNP5. Three different neutron sources were used in the study. The study re-examines the performance of the neutron backscattering methods in providing identification of hidden explosives through their chemical composition. The EBS neutron energy spectra of fast and slow neutrons of the major constituent elements in soil and an explosive material in form of TNT have shown definite structures that can be used for the identification of a buried landmine.

  12. A clean, bright, and versatile source of neutron decay products

    CERN Document Server

    Dubbers, D; Baessler, S; Maerkisch, B; Schumann, M; Soldner, T; Zimmer, O

    2007-01-01

    We present a case study on a new type of cold neutron beam station for the investigation of angular correlations in the beta-decay of free neutrons. With this beam station, called PERC, the 'active decay volume' lies inside the neutron guide, and the charged neutron decay products are magnetically guided towards the end of the neutron guide. Hence, the guide delivers at its exit a beam of decay electrons and protons, under well-defined and precisely variable conditions, which can be well separated from the cold neutron beam. In this way a general-purpose source of neutron decay products is obtained which can be used for various different experiments in neutron decay correlation spectroscopy. A gain in phase space density of several orders of magnitude can be achieved with PERC, as compared to existing neutron decay spectrometers. Neutron beam related background is separately measurable in PERC, and magnetic mirror effects on the charged neutron decay products and edge effects in the active neutron beam volume...

  13. Fuel cycle for a fusion neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Ananyev, S. S., E-mail: Ananyev-SS@nrcki.ru; Spitsyn, A. V., E-mail: spitsyn-av@nrcki.ru; Kuteev, B. V., E-mail: Kuteev-BV@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)

    2015-12-15

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion–fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium–tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m{sup 3}Pa/s, and temperature of reactor elements up to 650°C). The deuterium–tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  14. Fuel cycle for a fusion neutron source

    Science.gov (United States)

    Ananyev, S. S.; Spitsyn, A. V.; Kuteev, B. V.

    2015-12-01

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion-fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium-tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m3Pa/s, and temperature of reactor elements up to 650°C). The deuterium-tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  15. Fundamental neutron physics at a 1 MW long pulse spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Greene, G.L.

    1995-12-31

    Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research.

  16. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde, Raymond Keegan

    2008-07-01

    The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

  17. The European scene regarding spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Institut, Villigen (Austria)

    1996-06-01

    In Europe, a short pulse spallation neutron source, ISIS, has been operating for over 10 years, working its way up to a beam power level of 200 kW. A continuous source, SINQ, designed for a beam power of up to 1 MW, is scheduled to start operating at the end of 1996, and a detailed feasibility study has been completed for a 410 kW short pulse source, AUSTRON. Each of these sources seems to have settled for a target concept which is at or near the limits of its feasibility: The ISIS depleted uranium plate targets, heavy water cooled and Zircaloy clad, have so far not shown satisfactory service time and operation is likely to continue with a Ta-plate target, which, in the past has been used successfully for the equivalent of one full-beam-year before it was taken out of service due to degrading thermal properties. SINQ will initially use a rod target, made of Zircaloy only, but plans exist to move on to clad lead rods as quickly as possible. Apart from the not yet explored effect of hydrogen and helium production, there are also concerns about the generation of 7-Be in the cooling water from the spallation of oxygen, which might result in undesirably high radioactivity in the cooling plant room. A Liquid metal target, also under investigation for SINQ, would not only reduce this problem to a level of about 10 %, but would also minimize the risk of radiolytic corrosion in the beam interaction zone. Base on similar arguments, AUSTRON has been designed for edge cooled targets, but thermal and stress analyses show, that this concept is not feasible at higher power levels.

  18. REM meter for pulsed sources of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Thorngate, J.E.; Hunt, G.F.; Rueppel, D.W.

    1980-08-13

    A rem meter was constructed specifically for measuring neutrons produced by fusion experiments for which the source pulses last 10 ms or longer. The detector is a /sup 6/Li glass scintillator, 25.4 mm in diameter and 3.2 mm thick, surrounded by 11.5 cm of polyethylene. This detector has a sensitivity of 8.5 x 10/sup 4/ counts/mrem. The signals from this fast scintillator are shaped using a shorted delay line to produce pulses that are only 10 ns long so that dose equivalent rates up to 12 mrem/s can be measured with less than a 1% counting loss. The associated electronic circuits store detector counts only when the count rate exceeds a preset level. When the count rate returns to background, a conversion from counts to dose equivalent is made and the results are displayed. As a means of recording the number of source pulses that have occurred, a second display shows how many times the preset count rate has been exceeded. Accumulation of detector counts and readouts can also be controlled manually. The unit will display the integrated dose equilavent up to 200 mrem in 0.01 mrem steps. A pulse-height discriminator rejects gamma-ray interactions below 1 MeV, and the detector size limits the response above that energy. The instrument can be operated from an ac line or will run on rechargeable batteries for up to 12 hours.

  19. Production, Distribution, and Applications of Californium-252 Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial

  20. rf improvements for Spallation Neutron Source H-ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yoon W [ORNL; Fuja, Raymond E [ORNL; Goulding, Richard Howell [ORNL; Hardek, Thomas W [ORNL; Lee, Sung-Woo [ORNL; McCarthy, Mike [ORNL; Piller, Chip [ORNL; Shin, Ki [ORNL; Stockli, Martin P [ORNL; Welton, Robert F [ORNL

    2010-01-01

    The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering 38 mA H beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride AlN plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier. 2010 American Institute of Physics.

  1. Fissile mass estimation by pulsed neutron source interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Israelashvili, I., E-mail: israelashvili@gmail.com [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Dubi, C.; Ettedgui, H.; Ocherashvili, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Beck, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Roesgen, E.; Crochmore, J.M. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Ridnik, T.; Yaar, I. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel)

    2015-06-11

    Passive methods for detecting correlated neutrons from spontaneous fissions (e.g. multiplicity and SVM) are widely used for fissile mass estimations. These methods can be used for fissile materials that emit a significant amount of fission neutrons (like plutonium). Active interrogation, in which fissions are induced in the tested material by an external continuous source or by a pulsed neutron source, has the potential advantages of fast measurement, alongside independence of the spontaneous fissions of the tested fissile material, thus enabling uranium measurement. Until recently, using the multiplicity method, for uranium mass estimation, was possible only for active interrogation made with continues neutron source. Pulsed active neutron interrogation measurements were analyzed with techniques, e.g. differential die away analysis (DDA), which ignore or implicitly include the multiplicity effect (self-induced fission chains). Recently, both, the multiplicity and the SVM techniques, were theoretically extended for analyzing active fissile mass measurements, made by a pulsed neutron source. In this study the SVM technique for pulsed neutron source is experimentally examined, for the first time. The measurements were conducted at the PUNITA facility of the Joint Research Centre in Ispra, Italy. First promising results, of mass estimation by the SVM technique using a pulsed neutron source, are presented.

  2. Neutron spectra and dosimetric features of isotopic neutron sources: a review

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Martinez O, S. A., E-mail: fermineutron@yahoo.com [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia)

    2015-10-15

    A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of {sup 24}NaBe, {sup 24}NaD{sub 2}O, {sup 116}InBe, {sup 140}LaBe, {sup 238}PuLi, {sup 239}PuBe, {sup 241}AmB, {sup 241}AmBe, {sup 241}AmF, {sup 241}AmLi, {sup 242}CmBe, {sup 210}PoBe, {sup 226}RaBe, {sup 252}Cf and {sup 252}Cf/D{sub 2}O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

  3. Commissioning of the upgraded ultracold neutron source at Los Alamos Neutron Science Center

    Science.gov (United States)

    Pattie, Robert; LANL-UCN Team Team

    2016-09-01

    The spallation-driven solid-deuterium ultracold neutron (UCN) source at Los Alamos Neutron Science Center (LANSCE) has provided a facility for precision measurements of fundamental symmetries via the decay observables from neutron beta decay for nearly a decade. In preparation for a new room temperature neutron electric dipole moment (nEDM) experiment and to increase the statistical sensitivity of all experiments using the source an effort to upgrade the existing source has been carried out during 2016. This upgrade includes installing a redesigned cold neutron moderator and with optimized UCN converter geometries, improved coupling and nickel-phosphorus coating of the UCN transport system through the biological shielding, optimization of beam timing structure, and increase of the proton beam current. We will present the result of the commissioning run of the new source.

  4. Advanced Neutron Source (ANS) Project Progress report, FY 1991

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.H. (ed.) (Oak Ridge National Lab., TN (United States)); Selby, D.L.; Harrington, R.M. (Oak Ridge National Lab., TN (United States)); Thompson, P.B. (Martin Marietta Energy Systems, Inc., (United States). Engineering Division)

    1992-01-01

    This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I C Research and Development; Design; and Safety.

  5. Advanced Neutron Source (ANS) Project Progress report, FY 1991

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.H. [ed.] [Oak Ridge National Lab., TN (United States); Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., (United States). Engineering Division

    1992-01-01

    This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I & C Research and Development; Design; and Safety.

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

    CERN Document Server

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

    2004-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-05-05

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

  8. Bakelite chambers for time-of-flight measurements

    CERN Document Server

    Cwiok, M; Górski, M; Królikowski, J

    1999-01-01

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

  9. An orientable time of flight detector for cosmic rays

    CERN Document Server

    Iori, M

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-09-01

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

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

    CERN Document Server

    Hansard, Miles; Choi, Ouk; Horaud, Radu

    2012-01-01

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

  12. Correction of Errors in Time of Flight Cameras

    OpenAIRE

    Jiménez Cabello, David

    2015-01-01

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

  13. Physical design of positronium time of flight spectroscopy apparatus

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

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

    KAUST Repository

    Su, Shuochen

    2016-12-13

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

  15. Time of Flight Transients in the Dipolar Glass Model

    OpenAIRE

    2013-01-01

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

  16. Characterization of the radiation background at the Spallation Neutron Source

    Science.gov (United States)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.; Hall-Wilton, Richard J.; Bentley, Phillip M.

    2016-09-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.

  17. Inertial electrostatic confinement I(IEC) neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Nebel, R.A.; Barnes, D.C.; Caramana, E.J.; Janssen, R.D.; Nystrom, W.D.; Tiouririne, T.N.; Trent, B.C. [Los Alamos National Lab., NM (United States); Miley, G.H.; Javedani, J. [Illinois Univ., Urbana, IL (United States)

    1995-12-01

    Inertial Electrostatic Confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P.T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams. Gridded IEC systems have demonstrated neutron yields as high as 2*10 [10]. neutrons/sec in steady state. These systems have considerable potential as small, inexpensive, portable neutron sources for assaying applications. Neutron tomography is also a potential application. This paper discusses the IEC concept and how it can be adapted to a steady-state assaying source and an intense pulsed neutron source. Theoretical modeling and experimental results are presented.

  18. On the limit of neutron fluxes in the fission-based pulsed neutron sources

    Science.gov (United States)

    Aksenov, V. L.; Ananiev, V. D.; Komyshev, G. G.; Rogov, A. D.; Shabalin, E. P.

    2017-09-01

    The upper limit of the density of the thermal neutron flux from pulsed sources based on the fission reaction is established. Three types of sources for research on ejected beams are considered: a multiplying target of the proton accelerator (a booster), a booster with the reactivity modulation (a superbooster), and a pulsing reactor. Comparison with other high-flux sources is carried out. The investigation has been performed at the Frank Laboratory of Neutron Physics of JINR.

  19. Ultra-bright laser-driven neutron source

    Science.gov (United States)

    Roth, M.; Favalli, A.; Bagnoud, V.; Bridgewater, J.; Deppert, O.; Devlin, M.; Falk, K.; Fernndez, J.; Gautier, D.; Guler, N.; Henzlova, D.; Hornung, J.; Iliev, M.; Ianakiev, K.; Kleinschmidt, A.; Koehler, K.; Palaniyappan, S.; Poth, P.; Schaumann, G.; Swinhoe, M.; Taddeucci, T.; Tebartz, A.; Wagner, Florian; Wurden, G.

    2015-11-01

    Short-pulse laser-driven neutron sources have become a topic of interest since their brightness and yield have recently increased by orders of magnitude. Using novel target designs, high contrast - high power lasers and compact converter/moderator setups, these neutron sources have finally reached intensities that make many interesting applications possible. We present the results of two experimental campaigns on the GSI PHELIX and the LANL Trident lasers from 2015. We have produced an unprecedented neutron flux, mapped the spatial distribution of the neutron production as well as its energy spectra and ultimately used the beam for first applications to show the prospect of these new compact sources. We also made measurements for the conversion of energetic neutrons into short epithermal and thermal neutron pulses in order to evaluate further applications in dense plasma research. The results address a large community as it paves the way to use short pulse lasers as a neutron source. This can open up neutron research to a broad academic community including material science, biology, medicine and high energy density physics to universities and therefore can complement large scale facilities like reactors or particle accelerators.

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

  1. Isotopic characterization and thermal neutron flux determination of a PuBe neutron source.

    Science.gov (United States)

    Purty, Ravi Ankit; Akanchha; Prasad, Shikha

    2017-07-01

    The Indian Institute of Technology Kanpur (IIT Kanpur) possesses a PuBe neutron source facility with an initial activity of 5 Ci, dated September 1966 (nearly 50 years ago). An understanding of the present activity and the rate of its change will allow implementation of proper radiological safety procedures and future radiological safety planning. Knowing the absolute neutron flux will help us in future neutron activation studies. These details are also important to ensure proper security precautions. In our work, we attempt to identify the isotopic composition to determine the rate of change of the source and the absolute thermal neutron flux of plutonium beryllium (PuBe) sample at IIT Kanpur. We have used gamma-ray spectroscopy for determining the isotopic composition of the PuBe neutron source. After utilizing gamma-ray spectroscopy it is found that the source is composed of (239)Pu and a small amount of (241)Am is present as an impurity. The mass ratio of (241)Am to (239)Pu is found to be approximately 18.1µg/g with an uncertainty of 1.39%. Delayed gamma neutron activation analysis (DGNAA) is used to determine the thermal neutron flux of the same PuBe neutron source using copper, cobalt, nickel and cadmium samples. The average thermal neutron flux as calculated from DGNAA is approximately 1.27×10(3)n/(cm(2)-s) at 1cm above the PuBe neutron source. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Neutron shielding for a {sup 252} Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M. [Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Eduardo Gallego, Alfredo Lorente [Depto. de Ingenieria Nuclear, ETS Ingenieros Industriales, Universidad Politecnica de Madrid, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain)]. e-mail: fermineutron@yahoo.com

    2006-07-01

    To determine the neutron shielding features of water-extended polyester a Monte Carlo study was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through inelastic collisions and absorption reactions. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide production induced by neutron activation must be considered. In this investigation the Monte Carlo method was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source. During calculations a detailed model for the {sup 252}Cf and the shield was utilized. To compare the shielding features of water extended polyester, the calculations were also made for the bare {sup 252}Cf in vacuum, air and the shield filled with water. For all cases the calculated neutron spectra was utilized to determine the ambient equivalent neutron dose at four sites around the shielding. In the case of water extended polyester and water shielding the calculations were extended to include the prompt gamma rays produced during neutron interactions, with this information the Kerma in air was calculated at the same locations where the ambient equivalent neutron dose was determined. (Author)

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

    Science.gov (United States)

    Reiter, Moritz Pascal; Titan Collaboration

    2016-09-01

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

  4. The ALICE Time of Flight Readout System AFRO

    CERN Document Server

    Kluge, A

    1999-01-01

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

  5. LENS-a pulsed neutron source for education and research

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, David V. [Physics Department, Indiana University, Bloomington, IN 47405 (United States)]. E-mail: baxterd@indiana.edu; Cameron, J.M. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Leuschner, M.B. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Meyer, H.O. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Nann, H. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Snow, W.M. [Physics Department, Indiana University, Bloomington, IN 47405 (United States)

    2005-04-21

    At the Indiana University Cyclotron Facility construction of a new source of cold neutrons has begun. Neutrons are generated by stopping 13 MeV protons in a beryllium target, located at the center of a moderator structure. Cold neutrons are emitted from a slab of frozen methane. Three beam lines deliver neutrons for scattering experiments, radiography and moderator studies. The purpose of the project is to develop a low-cost, small-scale facility, suitable for a university or an industrial setting, to provide a testing ground of instrumentation destined for use at a larger facility, to improve awareness of the use of neutron probes in a wide range of applications, and to offer a training opportunity for future neutron physicists.

  6. Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

    Science.gov (United States)

    Ikeda, Yoshimasa; Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki; Kumagai, Masayoshi; Oba, Yojiro; Otake, Yoshie; Suzuki, Hiroshi

    2016-10-01

    A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

  7. Compact, energy EFFICIENT neutron source: enabling technology for various applications

    Energy Technology Data Exchange (ETDEWEB)

    Hershcovitch, A.; Roser, T.

    2009-12-01

    A novel neutron source comprising of a deuterium beam (energy of about 100 KeV) injected into a tube filled with tritium gas and/or tritium plasma that generates D-T fusion reactions, whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles, is described. At the opposite end of the tube, the energy of deuterium ions that did not interact is recovered. Beryllium walls of proper thickness can be utilized to absorb 14 MeV neutrons and release 2-3 low energy neutrons. Each ion source and tube forms a module. Larger systems can be formed from multiple units. Unlike currently proposed methods, where accelerator-based neutron sources are very expensive, large, and require large amounts of power for operation, this neutron source is compact, inexpensive, easy to test and to scale up. Among possible applications for this neutron source concept are sub-critical nuclear breeder reactors and transmutation of radioactive waste.

  8. Conceptual design of an RFQ accelerator-based neutron source for boron neutron-capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wangler, T.P.; Stovall, J.E.; Bhatia, T.S.; Wang, C.K.; Blue, T.E.; Gahbauer, R.A.

    1989-01-01

    We present a conceptual design of a low-energy neutron generator for treatment of brain tumors by boron neutron capture theory (BNCT). The concept is based on a 2.5-MeV proton beam from a radio-frequency quadrupole (RFQ) linac, and the neutrons are produced by the /sup 7/Li(p,n)/sup 7/Be reaction. A liquid lithium target and modulator assembly are designed to provide a high flux of epithermal neutrons. The patient is administered a tumor-specific /sup 10/Be-enriched compound and is irradiated by the neutrons to create a highly localized dose from the reaction /sup 10/B(n,..cap alpha..)/sup 7/Li. An RFQ accelerator-based neutron source for BNCT is compact, which makes it practical to site the facility within a hospital. 11 refs., 5 figs., 1 tab.

  9. An overview of an accelerator-based neutron spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.S.

    1996-06-01

    An overview of the feasibility study of a 1-MW pulsed spallation source is presented. The machine delivers 1 MW of proton beam power to spallation targets where slow neutrons are produced. The slow neutrons can be used for isotope production, materials irradiation, and neutron scattering research. The neutron source facility is based on a rapid cycling synchrotron (RCS) and consists of a 400-MeV linac, a 30-Hz RCS that accelerates the 400-MeV beam to 2 GeV, and two neutron-generating target stations. The RCS accelerates an average proton beam current of 0.5 mA, corresponding to 1.04 x 10{sup 14} protons per pulse. This intensity is about two times higher than that of existing machines. A key feature of this accelerator system design is that beam losses are minimized from injection to extraction, reducing activation to levels consistent with hands-on maintenance.

  10. Characteristics of the WNR: a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

    1982-01-01

    The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented.

  11. Advanced Neutron Source radiological design criteria

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, J.L.

    1995-08-01

    The operation of the proposed Advanced Neutron Source (ANS) facility will present a variety of radiological protection problems. Because it is desired to design and operate the ANS according to the applicable licensing standards of the Nuclear Regulatory Commission (NRC), it must be demonstrated that the ANS radiological design basis is consistent not only with state and Department of Energy (DOE) and other usual federal regulations, but also, so far as is practicable, with NRC regulations and with recommendations of such organizations as the Institute of Nuclear Power Operations (INPO) and the Electric Power Research Institute (EPRI). Also, the ANS radiological design basis is in general to be consistent with the recommendations of authoritative professional and scientific organizations, specifically the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP). As regards radiological protection, the principal goals of DOE regulations and guidance are to keep occupational doses ALARA [as low as (is) reasonably achievable], given the current state of technology, costs, and operations requirements; to control and monitor contained and released radioactivity during normal operation to keep public doses and releases to the environment ALARA; and to limit doses to workers and the public during accident conditions. Meeting these general design objectives requires that principles of dose reduction and of radioactivity control by employed in the design, operation, modification, and decommissioning of the ANS. The purpose of this document is to provide basic radiological criteria for incorporating these principles into the design of the ANS. Operations, modification, and decommissioning will be covered only as they are affected by design.

  12. Lithium neutron producing target for BINP accelerator-based neutron source.

    Science.gov (United States)

    Bayanov, B; Belov, V; Kindyuk, V; Oparin, E; Taskaev, S

    2004-11-01

    Pilot innovative accelerator-based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. One of the main elements of the facility is lithium target, that produces neutrons via threshold (7)Li(p,n)(7)Be reaction at 25 kW proton beam with energies 1.915 or 2.5 MeV. In the present report, the results of experiments on neutron producing target prototype are presented, the results of calculations of hydraulic resistance for heat carrier flow and lithium layer temperature are shown. Calculation showed that the lithium target could run up to 10 mA proton beam before melting. Choice of target variant is substantiated. Program of immediate necessary experiments is described. Target design for neutron source constructed at BINP is presented. Manufacturing the neutron producing target up to the end of 2004 and obtaining a neutron beam on BINP accelerator-based neutron source are planned during 2005.

  13. Lithium neutron producing target for BINP accelerator-based neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Bayanov, B.; Belov, V.; Kindyuk, V.; Oparin, E.; Taskaev, S. E-mail: taskaev@inp.nsk.su

    2004-11-01

    Pilot innovative accelerator-based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. One of the main elements of the facility is lithium target, that produces neutrons via threshold {sup 7}Li(p,n){sup 7}Be reaction at 25 kW proton beam with energies 1.915 or 2.5 MeV. In the present report, the results of experiments on neutron producing target prototype are presented, the results of calculations of hydraulic resistance for heat carrier flow and lithium layer temperature are shown. Calculation showed that the lithium target could run up to 10 mA proton beam before melting. Choice of target variant is substantiated. Program of immediate necessary experiments is described. Target design for neutron source constructed at BINP is presented. Manufacturing the neutron producing target up to the end of 2004 and obtaining a neutron beam on BINP accelerator-based neutron source are planned during 2005.

  14. Investigation of Isfahan miniature neutron source reactor (MNSR for boron neutron capture therapy by MCNP simulation

    Directory of Open Access Journals (Sweden)

    S.Z Kalantari

    2015-01-01

    Full Text Available One of the important neutron sources for Boron Neutron Capture Therapy (BNCT is a nuclear reactor. It needs a high flux of epithermal neutrons. The optimum conditions of the neutron spectra for BNCT are provided by the International Atomic Energy Agency (IAEA. In this paper, Miniature Neutron Source Reactor (MNSR as a neutron source for BNCT was investigated. For this purpose, we designed a Beam Shaping Assembly (BSA for the reactor and the neutron transport from the core of the reactor to the output windows of BSA was simulated by MCNPX code. To optimize the BSA performance, two sets of parameters should be evaluated, in-air and in-phantom parameters. For evaluating in-phantom parameters, a Snyder head phantom was used and biological dose rate and dose-depth curve were calculated in brain normal and tumor tissues. Our calculations showed that the neutron flux of the MNSR reactor can be used for BNCT, and the designed BSA in optimum conditions had a good therapeutic characteristic for BNCT.

  15. An ultra-cold neutron source at the MLNSC

    Energy Technology Data Exchange (ETDEWEB)

    Bowles, T.J.; Brun, T.; Hill, R.; Morris, C.; Seestrom, S.J. [Los Alamos National Lab., NM (United States); Crow, L. [Univ. of Rhode Island, Kingston, RI (United States); Serebrov, A. [Petersburg Nuclear Physics Inst. (Russian Federation)

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have carried out the research and development of an Ultra-Cold Neutron (UCN) source at the Manuel Lujan Neutron Scattering Center (MLNSC). A first generation source was constructed to test the feasibility of a rotor source. The source performed well with an UCN production rate reasonably consistent with that expected. This source can now provide the basis for further development work directed at using UCN in fundamental physics research as well as possible applications in materials science.

  16. Optimal Neutron Source and Beam Shaping Assembly for Boron Neutron Capture Therapy

    CERN Document Server

    Vujic, J L; Greenspan, E; Guess, S; Karni, Y; Kastenber, W E; Kim, L; Leung, K N; Regev, D; Verbeke, J M; Waldron, W L; Zhu, Y

    2003-01-01

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  17. Neutron activation analysis: Modelling studies to improve the neutron flux of Americium–Beryllium source

    National Research Council Canada - National Science Library

    Abdessamad Didi; Ahmed Dadouch; Otman Jaï; Jaouad Tajmouati; Hassane El Bekkouri

    2017-01-01

    Americium–beryllium (Am-Be; n, γ) is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences...

  18. Optimal Neutron Source & Beam Shaping Assembly for Boron Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    J. Vujic; E. Greenspan; W.E. Kastenber; Y. Karni; D. Regev; J.M. Verbeke, K.N. Leung; D. Chivers; S. Guess; L. Kim; W. Waldron; Y. Zhu

    2003-04-30

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  19. Design and demonstration of a quasi-monoenergetic neutron source

    CERN Document Server

    Joshi, T H; Mozin, V; Norman, E B; Sorensen, P; Foxe, M; Bench, G; Bernstein, A

    2014-01-01

    The design of a neutron source capable of producing 24 and 70 keV neutron beams with narrow energy spread is presented. The source exploits near-threshold kinematics of the $^{7}$Li(p,n)$^{7}$Be reaction while taking advantage of the interference `notches' found in the scattering cross-sections of iron. The design was implemented and characterized at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory. Alternative filters such as vanadium and manganese are also explored and the possibility of studying the response of different materials to low-energy nuclear recoils using the resultant neutron beams is discussed.

  20. An intense 14 MeV neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Su Tongling; Sun Biehe; Yang Baotai; Piao Yubo; Shui Yongqing; Chen Kefan; Wang Xuezhi; Yang Cheng; Niu Zhanqi; Liu Yanton; Pan Minshen; Hong Zhongti; Chen Qin (Lanzhou Univ., GS (China). Inst. of Nuclear Research)

    1990-02-15

    A 3x10{sup 12} n/s source of 14 MeV neutrons is described in this paper. The neutrons are produced by the T(d,n){sup 4}He reaction under a 30 mA, 300 keV deuteron beam bombarding a water-cooled, rotating titanium-tritide target. The size of the beam spot on the target is 1.8 cm, and at the distance of closest approach to the source a neutron flux of 5x10{sup 11} n/cm{sup 2} s is obtained. (orig.).

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

    Science.gov (United States)

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

    2014-02-11

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

  2. Secondary neutron source modelling using MCNPX and ALEPH codes

    Science.gov (United States)

    Trakas, Christos; Kerkar, Nordine

    2014-06-01

    Monitoring the subcritical state and divergence of reactors requires the presence of neutron sources. But mainly secondary neutrons from these sources feed the ex-core detectors (SRD, Source Range Detector) whose counting rate is correlated with the level of the subcriticality of reactor. In cycle 1, primary neutrons are provided by sources activated outside of the reactor (e.g. Cf252); part of this source can be used for the divergence of cycle 2 (not systematic). A second family of neutron sources is used for the second cycle: the spontaneous neutrons of actinides produced after irradiation of fuel in the first cycle. Both families of sources are not sufficient to efficiently monitor the divergence of the second cycles and following ones, in most reactors. Secondary sources cluster (SSC) fulfil this role. In the present case, the SSC [Sb, Be], after activation in the first cycle (production of Sb124, unstable), produces in subsequent cycles a photo-neutron source by gamma (from Sb124)-neutron (on Be9) reaction. This paper presents the model of the process between irradiation in cycle 1 and cycle 2 results for SRD counting rate at the beginning of cycle 2, using the MCNPX code and the depletion chain ALEPH-V1 (coupling of MCNPX and ORIGEN codes). The results of this simulation are compared with two experimental results of the PWR 1450 MWe-N4 reactors. A good agreement is observed between these results and the simulations. The subcriticality of the reactors is about at -15,000 pcm. Discrepancies on the SRD counting rate between calculations and measurements are in the order of 10%, lower than the combined uncertainty of measurements and code simulation. This comparison validates the AREVA methodology, which allows having an SRD counting rate best-estimate for cycles 2 and next ones and optimizing the position of the SSC, depending on the geographic location of sources, main parameter for optimal monitoring of subcritical states.

  3. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Science.gov (United States)

    Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

    2014-12-01

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  4. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga.vadim@gmail.com [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Izotov, I.; Golubev, S.; Razin, S. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Sidorov, A. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Maslennikova, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State Medical Academy, 10/1 Minina Sq., 603005 Nizhny Novgorod (Russian Federation); Volovecky, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Tarvainen, O. [University of Jyvaskyla, Department of Physics, PO Box 35 (YFL), 40500 Jyväskylä (Finland)

    2014-12-21

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D–D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm{sup 2} is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·10{sup 10} cm{sup −2}/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  5. 实时直接分析离子源-飞行时间质谱法快速筛查安非他明类物质%Rapid Screening of Amphetamines by Time-of-Flight Mass Spectrometry Coupled with Direct Analysis in Real Time Ion Source

    Institute of Scientific and Technical Information of China (English)

    连茹; 吴忠平; 吕小宝; 汪蓉; 倪春芳; 张玉荣

    2016-01-01

    A method for rapid screening of 8 amphetamines in drug samples was developed based on time of flight mass spectrometry (TOF-MS)coupled with direct analysis in real time (DART)ion source.Ion source temperature of 400 ℃,grid voltage of 200 V and the injection rate of 0.4 mm·s-1 were adopted in DART,and positive ion mode and orificel voltages of 30,60 V were adopted in TOF-MS for analysis of the 8 amphetamines.A screening database of accurate relative molecular mass of informative precursor ions and fragment ions was established for the rapid qualitative analysis of the 8 amphetamines in drug samples.The detection limits of the 8 amphetamines ranged from 0.05 to 0.1 mg·L-1 .The fragmentation regularity of the 8 amphetamines in DART ion source was analysized.%采用实时直接分析(DART)离子源结合飞行时间质谱法(TOF-MS),提出了一种快速筛查毒品检材中安非他明类物质的方法。DART 离子源温度400℃,栅极电压200 V,进样速率0.4 mm·s-1。飞行时间质谱中选择正离子模式,孔1电压为30 V 和60 V,分析8种安非他明类物质。通过得到的具有精确相对分子质量的准分子离子峰和两个以上的碎片离子峰建立筛查数据库,对检材中的安非他明类物质进行快速定性分析。8种安非他明类物质的检出限在0.05~0.1 mg·L-1之间。并分析了8种安非他明类物质在 DART 离子源下的裂解规律。

  6. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values.

  7. Time-of-Flight Cameras in Computer Graphics

    DEFF Research Database (Denmark)

    Kolb, Andreas; Barth, Erhardt; Koch, Reinhard

    2010-01-01

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

  8. Time-of-Flight Sensors in Computer Graphics

    DEFF Research Database (Denmark)

    Kolb, Andreas; Barth, Erhardt; Koch, Reinhard

    2009-01-01

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

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

    Science.gov (United States)

    Terra, Osama; Hussein, Hatem

    2016-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

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

    Science.gov (United States)

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

    2015-08-01

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

  12. Time Of Flight Detectors: From phototubes to SiPM

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

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

    CERN Document Server

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

    2015-01-01

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

  15. DUNBID, the Delft University neutron backscattering imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Bom, V.R. [Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)]. E-mail: vb@iri.tudelft.nl; Eijk, C.W.E. van [Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Ali, M.A. [Atomic Energy Authority, Nuclear Research Center, Reactor and Neutron Physics Department, P.O. Box 13759, Abu Zabal, Cairo (Egypt)

    2005-12-01

    In the search for low-metallic land mines, the neutron backscattering technique may be applied if the soil is sufficiently dry. An advantage of this method is the speed of detection: the scanning speed may be made comparable to that of a metal detector. A two-dimensional position sensitive detector is tested to obtain an image of the back scattered thermal neutron radiation. Results of experiments using a radionuclide neutron source are presented. The on-mine to no-mine signal ratio can be improved by the application of a window on the neutron time-of-flight. Results using a pulsed neutron generator are also presented.

  16. Systematic neutron guide misalignment for an accelerator-driven spallation neutron source

    Science.gov (United States)

    Zendler, C.; Bentley, P. M.

    2016-08-01

    The European Spallation Source (ESS) is a long pulse spallation neutron source that is currently under construction in Lund, Sweden. A considerable fraction of the 22 planned instruments extend as far as 75-150 m from the source. In such long beam lines, misalignment between neutron guide segments can decrease the neutron transmission significantly. In addition to a random misalignment from installation tolerances, the ground on which ESS is built can be expected to sink with time, and thus shift the neutron guide segments further away from the ideal alignment axis in a systematic way. These systematic errors are correlated to the ground structure, position of buildings and shielding installation. Since the largest deformation is expected close to the target, even short instruments might be noticeably affected. In this study, the effect of this systematic misalignment on short and long ESS beam lines is analyzed, and a possible mitigation by overillumination of subsequent guide sections investigated.

  17. Neutron beam line design of a white neutron source at CSNS

    Science.gov (United States)

    Jing, Hantao; Zhang, Liying; Tang, Jingyu; Ruan, Xichao; Ning, Changjun; Yu, Yongji; Wang, Pengcheng; Li, Qiang; Ren, Jie; Tang, Hongqing; Wang, Xiangqi

    2017-09-01

    China Spallation Neutron Source (CSNS), which is under construction, is a large scientific facility dedicated mainly for multi-disciplinary research on material characterization using neutron scattering techniques. The CSNS Phase-I accelerator will deliver a proton beam with an energy of 1.6 GeV and a pulse repetition rate of 25 Hz to a tungsten target, and the beam power is 100 kW. A white neutron source using the back-streaming neutrons through the incoming proton beam channel was proposed and is under construction. The back-streaming neutrons which are very intense and have good time structure are very suitable for nuclear data measurements. The white neutron source includes an 80-m neutron beam line, two experimental halls, and also six different types of spectrometers. The physics design of the beam line is presented in this paper, which includes beam optics and beam characterization simulations, with the emphasis on obtaining extremely low background. The first-batch experiments on nuclear data measurements are expected to be conducted in late 2017.

  18. Neutron production by neutral beam sources

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V.; Ruby, L.

    1979-11-01

    Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments.

  19. Neutron dosimetry, moderated energy spectrum, and neutron capture therapy for californium-252 medical sources

    Science.gov (United States)

    Rivard, Mark Joseph

    Examination of neutron dosimetry for 252Cf has been conducted using calculative and experimental means. Monte Carlo N-Particle (MCNP) transport code was used in a distributed computing environment as a parallel virtual machine (PVM) to determine the absorbed neutron dose and neutron energy spectrum from 252Cf in a variety of clinically relevant materials. Herein, a Maxwellian spectrum was used to model the 252Cf neutron emissions within these materials. 252Cf mixed-field dosimetry of Applicator Tube (AT) type sources was measured using 1.0 and 0.05 cm3 tissue-equivalent ion chambers and a miniature GM counter. A dosimetry protocol was formulated similar that of ICRU 45. The 252Cf AT neutron dosimetry was determined in the cylindrical coordinate system formalism recommended by the AAPM Task Group 43. These results demonstrated the overwhelming dependence of dosimetry on the source geometry factor as there was no significant neutron attenuation within the source or encapsulation. Gold foils and TLDs were used to measure the thermal flux in the vicinity of 252Cf AT sources to compare with the results calculated using MCNP. As the fast neutron energy spectrum did not markedly changed at increasing distances from the AT source, neutron dosimetry results obtained with paired ion chambers using fixed sensitivity factors agreed well with MCNP results and those in the literature. Calculations of moderated 252Cf neutron energy spectrum with various loadings of 10B and 157Gd were performed, in addition to analysis of neutron capture therapy dosimetry with these isotopes. Radiological concerns such as personnel exposure and shielding of 252Cf emissions were examined. Feasibility of a high specific-activity 252Cf HDR source was investigated through radiochemical and metallurgical studies using stand-ins such as Tb, Gd and 249Cf. Issues such as capsule burst strength due to helium production for a variety of proposed HDR sources were addressed. A recommended 252Cf source

  20. New Techniques in Neutron Scattering

    DEFF Research Database (Denmark)

    Birk, Jonas Okkels

    . The instrument is ideally suited for solid state experiments with extreme sample environments such as large pressures and strong magnetic fields. CAMEA combines the time-of-flight technique to determine the energy of the incoming neutrons with a complex multiplex backend that will analyse and detect......Neutron scattering is an important experimental technique in amongst others solid state physics, biophysics, and engineering. This year construction of European Spallation Source (ESS) was commenced in Lund, Sweeden. The facility will use a new long pulsed source principle to obtain higher...

  1. Status report on the Low Energy Neutron Source for 2015

    Science.gov (United States)

    Baxter, D. V.; Rinckel, T.

    2016-11-01

    The Low Energy Neutron Source at Indiana University first produced cold neutrons in April of 2005. Ten years after first reaching this milestone, the facility has three instruments in operation on its cold target station, and a second target station is devoted to thermal and fast neutron physics offers capabilities in radiation effects research (single-event effects in electronics) and radiography. Key elements in our success over these last ten years have been the diversity of activities we have been able maintain (which often involves using each of our instruments for multiple different activities), the close relationship we have developed with a number of major sources, and the focus we have had on innovation in neutron instrumentation. In this presentation, we will introduce some of the highlights from our most recent activities, provide an update on some of our technical challenges, and describe some of our ideas for the future.

  2. Research for the concept of Hanaro cold neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chang Oong; Cho, M. S.; Lee, M. W.; Sohn, J. M.; Park, K. N.; Park, S. H.; Yang, S. Y.; Kang, S. H.; Yang, S. H.; Chang, J. H.; Lee, Y. W.; Chang, C. I.; Cho, Y. S.

    1997-09-01

    This report consists of two parts, one is the conceptual design performed on the collaboration work with PNPI Russia and another is review of Hanaro CNS conceptual design report by Technicatome France, both of which are contained at vol. I and vol. II. representatively. In the vol. I, the analysis for the status of technology development, the technical characteristics of CNS is included, and the conceptual design of Hanaro cold neutron source is contained to establish the concept suitable to Hanaro. The cold neutron experimental facilities, first of all, have been selected to propose the future direction of physics concerning properties of the matter at Korea. And neutron guide tubes, the experimental hall and cold neutron source appropriate to these devices have been selected and design has been reviewed in view of securing safety and installing at Hanaro. (author). 38 refs., 49 tabs., 17 figs.

  3. Characterization of nuclear sources via two-neutron intensity interferometry

    CERN Document Server

    Ghetti, R; Helgesson, J; De Filippo, E; Tagliente, G; Anzalone, A; Bellini, V; Carlén, L; Cavallaro, S; Celano, L; D'Erasmo, G; Di Santo, D; Fiore, E M; Fokin, A; Geraci, M; Jakobsson, B; Kuznetsov, A; Lanzanò, G; Mahboub, D; Murin, Yu A; Maartensson, J; Pagano, A; Palazzolo, F; Palomba, M; Pantaleo, A; Paticchio, V; Potenza, R; Riera, G; Siwek, A; Sperduto, M L; Sutera, C; Urrata, M; Westerberg, L

    1999-01-01

    The neutron energy spectrum and the two-neutron correlation function have been measured for the E/A=45 MeV Ni + Al reaction in order to assess the space-time characteristics of the neutron emitting source. When comparing the data to a statistical model, the kinetic energy spectra, the integrated correlation function as well as the longitudinal correlation function are reproduced by one single source. However, only the inclusion of a short-lived pre-equilibrium component can account for the stronger correlation exhibited by neutron pairs emitted with high total momentum. The correlation function from events defined as peripheral by constraints on the highest charge of the projectile-like fragment does show a significantly weaker correlation than the minimum bias sample.

  4. Research opportunities with compact accelerator-driven neutron sources

    Science.gov (United States)

    Anderson, I. S.; Andreani, C.; Carpenter, J. M.; Festa, G.; Gorini, G.; Loong, C.-K.; Senesi, R.

    2016-10-01

    Since the discovery of the neutron in 1932 neutron beams have been used in a very broad range of applications, As an aging fleet of nuclear reactor sources is retired the use of compact accelerator-driven neutron sources (CANS) is becoming more prevalent. CANS are playing a significant and expanding role in research and development in science and engineering, as well as in education and training. In the realm of multidisciplinary applications, CANS offer opportunities over a wide range of technical utilization, from interrogation of civil structures to medical therapy to cultural heritage study. This paper aims to provide the first comprehensive overview of the history, current status of operation, and ongoing development of CANS worldwide. The basic physics and engineering regarding neutron production by accelerators, target-moderator systems, and beam line instrumentation are introduced, followed by an extensive discussion of various evolving applications currently exploited at CANS.

  5. Comparison of ultracold neutron sources for fundamental physics measurements

    CERN Document Server

    Bison, G; Kirch, K; Lauss, B; Ries, D; Schmidt-Wellenburg, P; Zsigmond, G; Brenner, T; Geltenbort, P; Jenke, T; Zimmer, O; Beck, M; Heil, W; Kahlenberg, J; Karch, J; Ross, K; Eberhardt, K; Geppert, C; Karpuk, S; Reich, T; Siemensen, C; Sobolev, Y; Trautmann, N

    2016-01-01

    Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.

  6. Target station shielding issues at the spallation neutron source.

    Science.gov (United States)

    Ferguson, P D; Gallmeier, F X; Iverson, E B; Popova, I I

    2005-01-01

    Recent spallation neutron source shielding activities in support of the neutron beam shutters and the hot cell walls are presented. Existing neutron beam shutters can be replaced with concrete at low power or with concrete and steel at approximately 500 kW of beam power. Potential voids in the hot cell walls are analysed to determine the impact on dose rates as a function of void size. A change in the type of shielding work is noted as the project moved from the early design stages as a 'green field' site to the current stage as a construction project nearing completion, where issues to be addressed are approaching retrofit-type analyses.

  7. Enhanced Performance Neutron Scattering Spectroscopy by Use of Correlation Techniques

    CERN Document Server

    Mezei, F; Migliardo, F; Magazù, S

    2016-01-01

    Neutron correlation spectroscopy can exceed direct spectroscopy in the incoming beam intensity by up to two orders of magnitude at the same energy resolution. However, the propagation of the counting noise in the correlation algorithm of data reduction is disadvantageous for the lowest intensity parts of the observed spectrum. To mitigate this effect at pulsed neutron sources we propose two dimensional time-of-flight recording of each neutron detection event: with respect to both the neutron source pulses and to the rotation phase of the pseudo-random beam modulation statistical chopper. We have identified a formulation of the data reduction algorithm by matching the data processing time channel width to the inherent time resolution of this chopper, which makes the reconstruction of the direct time-of-flight spectra exact and independent of all other contributions to instrumental resolution. Two ways are proposed for most flexible choice of intensity vs. resolution without changing the statistical chopper or ...

  8. Plans for an Ultra Cold Neutron source at Los Alamos

    Energy Technology Data Exchange (ETDEWEB)

    Seestrom, S.J.; Bowles, T.J.; Hill, R.; Greene, G.L. [Los Alamos National Lab., NM (United States)

    1996-08-01

    Ultra Cold Neutrons (UCN) can be produced at spallation sources using a variety of techniques. To date the technique used has been to Bragg scatter and Doppler shift cold neutrons into UCN from a moving crystal. This is particularly applicable to short-pulse spallation sources. We are presently constructing a UCN source at LANSCE using method. In addition, large gains in UCN density should be possible using cryogenic UCN sources. Research is under way at Gatchina to demonstrate technical feasibility of be a frozen deuterium source. If successful, a source of this type could be implemented at future spallation source, such as the long pulse source being planned at Los Alamos, with a UCN density that may be two orders of magnitude higher than that presently available at reactors. (author)

  9. Fission reactor neutron sources for neutron capture therapy--a critical review.

    Science.gov (United States)

    Harling, Otto K; Riley, Kent J

    2003-01-01

    The status of fission reactor-based neutron beams for neutron capture therapy (NCT) is reviewed critically. Epithermal neutron beams, which are favored for treatment of deep-seated tumors, have been constructed or are under construction at a number of reactors worldwide. Some of the most recently constructed epithermal neutron beams approach the theoretical optimum for beam purity. Of these higher quality beams, at least one is suitable for use in high through-put routine therapy. It is concluded that reactor-based epithermal neutron beams with near optimum characteristics are currently available and more can be constructed at existing reactors. Suitable reactors include relatively low power reactors using the core directly as a source of neutrons or a fission converter if core neutrons are difficult to access. Thermal neutron beams for NCT studies with small animals or for shallow tumor treatments, with near optimum properties have been available at reactors for many years. Additional high quality thermal beams can also be constructed at existing reactors or at new, small reactors. Furthermore, it should be possible to design and construct new low power reactors specifically for NCT, which meet all requirements for routine therapy and which are based on proven and highly safe reactor technology.

  10. Neutron Radiographic Inspection of Industrial Components using Kamini Neutron Source Facility

    Science.gov (United States)

    Raghu, N.; Anandaraj, V.; Kasiviswanathan, K. V.; Kalyanasundaram, P.

    2008-03-01

    Kamini (Kalpakkam Mini) reactor is a U233 fuelled, demineralised light water moderated and cooled, beryllium oxide reflected, low power (30 kW) nuclear research reactor. This reactor functions as a neutron source with a flux of 1012 n/cm2 s-1 at core centre with facilitates for carrying out neutron radiography, neutron activation analysis and neutron shielding experiments. There are two beam tubes for neutron radiography. The length/diameter ratio of the collimators is about 160 and the aperture size is 220 mm×70 mm. Flux at the outer end of the beam tube is ˜106-107 n/cm2 s. The north end beam tube is for radiography of inactive object while the south side beam tube is for radiography of radioactive objects. The availability of high neutron flux coupled with good collimated beam provides high quality radiographs with short exposure time. The reactor being a unique national facility for neutron radiography has been utilized in the examination of irradiated components, aero engine turbine blades, riveted plates, automobile chain links and for various types of pyro devices used in the space programme. In this paper, an overview of the salient features of this reactor facility for neutron radiography and our experience in the inspection of a variety of industrial components will be given.

  11. Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.

    Science.gov (United States)

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and

  12. Irradiation facilities at the spallation neutron source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Ledermann, J.; Aebersold, H.; Kuehne, G.; Kohlik, K. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Four independent experiments for sample irradiation are under construction and in preparation for operational tests at the spallation source SINQ. Three of them are located inside a thermal beam port with end positions inside or near the moderator tank. The other experiment will be established at the end position of a super mirror lined neutron guide for applications with cold neutrons. (author) 3 figs., 1 tab., 6 refs.

  13. Pulsed neutron source based on accelerator-subcritical-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Okamoto, Hiromi; Shirai, Toshiyuki [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

    1997-03-01

    A new pulsed neutron source which consists of a 300MeV proton linac and a nuclear fuel subcritical assembly is proposed. The proton linac produces pulsed spallation neutrons, which are multipied by the subcritical assembly. A prototype proton linac that accelerates protons up to 7MeV has been developed and a high energy section of a DAW structure is studied with a power model. Halo formations in high intensity beam are also being studied. (author)

  14. Time-correlated neutron analysis of a multiplying HEU source

    Energy Technology Data Exchange (ETDEWEB)

    Miller, E.C., E-mail: Eric.Miller@jhuapl.edu [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Kalter, J.M.; Lavelle, C.M. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Watson, S.M.; Kinlaw, M.T.; Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID (United States); Noonan, W.A. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States)

    2015-06-01

    The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated {sup 3}He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

  15. STUDY ON MODERATIORS OF SMALL—SIZE NEUTRON RADIOGRAPHY INSTALLATIONS WITH NEUTRON TUBE AS SOURCE

    Institute of Scientific and Technical Information of China (English)

    马维超; 吴执中; 等

    1995-01-01

    Calculation of moderator analogues for 14 MeV neutrons as source were made at a IBM/PC AT computer using TAMAKER-ANISN program and 46 groups(25 neutron groups,21 photon groups) UW cross section data.The intensifying effect of lead and natural uranium for moderating 14 MeV neutrons is confirmed.Adopting proper structure of the moderator,the intensifying factor M( times) may be larger than 3.Using lead and naural uranium in sub-critical assemblies (or cell boosters),with 14 Me neutrons as source,with the same dimension as that of abouve,the intensifying effect is also confirmed.With a proper structure of sub-critical assembly,the intensifying factor M may be close to or even larger than(1-k)-1 where k is the effective multiplication factor.

  16. High Intensity Accelerator and Neutron Source in China

    Science.gov (United States)

    Guan, Xialing; Wei, J.; Loong, Chun

    2011-06-01

    High intensity Accelerator is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. The R/D activities of the technology of High intensity accelerator are also developed in China for some year, and have some good facilities around China. This paper will reports the status of some high intensity accelerators and neutron source in China, which including ADS/RFQ; CARR; CSNS; PKUNIFTY & CPHS. This paper will emphatically report the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China.

  17. Method to determine the strength of a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Chacon R, A.; Mercado, G.A. [UAZ, A.P. 336, 98000 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Depto. Ingenieria Nuclear, Universidad Politecnica de Madrid, (Spain)

    2006-07-01

    The use of a gamma-ray spectrometer with a 3 {phi} x 3 NaI(Tl) detector, with a moderator sphere has been studied in the aim to measure the neutron fluence rate and to determine the source strength. Moderators with a large amount of hydrogen are able to slowdown and thermalize neutrons; once thermalized there is a probability that thermal neutron to be captured by hydrogen producing 2.22 MeV prompt gamma-ray. The pulse-height spectrum collected in a multicharmel analyzer shows a photopeak around 2.22 MeV whose net area is proportional to total neutron fluence rate and to the neutron source strength. The characteristics of this system were determined by a Monte Carlo study using the MCNP 4C code, where a detailed model of the Nal(Tl) was utilized. As moderators 3, 5, and 10 inches-diameter spheres where utilized and the response was calculated for monoenergetic and isotopic neutrons sources. (Author)

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

    Science.gov (United States)

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

    2007-01-01

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

  19. BNL ACTIVITIES IN ADVANCED NEUTRON SOURCE DEVELOPMENT: PAST AND PRESENT

    Energy Technology Data Exchange (ETDEWEB)

    HASTINGS,J.B.; LUDEWIG,H.; MONTANEZ,P.; TODOSOW,M.; SMITH,G.C.; LARESE,J.Z.

    1998-06-14

    Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In the sections below the authors discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

  20. BNL Activities in Advanced Neutron Source Development: Past and Present

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; Ludewig, H.; Montanez, P.; Todosow, M.; Smith, G.C.; Larese, J.Z.

    1998-06-14

    Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In this report we discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

  1. Optimization of an accelerator-based epithermal neutron source for neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kononov, O.E.; Kononov, V.N.; Bokhovko, M.V.; Korobeynikov, V.V.; Soloviev, A.N.; Chu, W.T.

    2004-02-20

    A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the 7Li(p,n)7Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine. Results of calculation were experimentally tested and are in good agreement with measurements.

  2. Proton Transfer Time-of-Flight Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-01

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

  3. Proposed STAR Time of Flight Readout Electronics and DAQ

    Science.gov (United States)

    Schambach, Joachim

    2006-04-01

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

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

    Science.gov (United States)

    Berretti, Mirko

    2017-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Karp, Joel (University of Pennsylvania)

    2004-09-29

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

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

    Science.gov (United States)

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

    2015-02-01

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

  7. Instrumentation for time of-flight position emission tomography

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-15

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

  8. Constant-momentum acceleration time-of-flight mass spectrometry with energy focusing.

    Science.gov (United States)

    Dennis, Elise A; Ray, Steven J; Gundlach-Graham, Alexander W; Enke, Christie G; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

    2013-12-01

    Fundamental aspects of constant-momentum acceleration time-of-flight mass spectrometry (CMA-TOFMS) are explored as a means to improve mass resolution. By accelerating all ions to the same momentum rather than to the same energy, the effects of the initial ion spatial and energy distributions upon the total ion flight time are decoupled. This decoupling permits the initial spatial distribution of ions in the acceleration region to be optimized independently, and energy focus, including ion turn-around-time error, to be accomplished with a linear-field reflectron. Constant-momentum acceleration also linearly disperses ions across time according to mass-to-charge (m/z) ratio, instead of the quadratic relationship between flight time and m/z found in conventional TOFMS. Here, CMA-TOFMS is shown to achieve simultaneous spatial and energy focusing over a selected portion of the mass spectrum. An orthogonal-acceleration time-of-flight system outfitted with a reduced-pressure DC glow discharge (GD) ionization source is used to demonstrate CMA-TOFMS with atomic ions. The influence of experimental parameters such as the amplitude and width of the time-dependent CMA pulse on mass resolution is investigated, and a useful CMA-TOFMS focusing window of 2 to 18 Da is found for GD-CMA-TOFMS.

  9. TOF plotter—a program to perform routine analysis time-of-flight mass spectral data

    Science.gov (United States)

    Knippel, Brad C.; Padgett, Clifford W.; Marcus, R. Kenneth

    2004-03-01

    The main article discusses the operation and application of the program to mass spectral data files. This laboratory has recently reported the construction and characterization of a linear time-of-flight mass spectrometer (ToF-MS) utilizing a radio frequency glow discharge ionization source. Data acquisition and analysis was performed using a digital oscilloscope and Microsoft Excel, respectively. Presently, no software package is available that is specifically designed for time-of-flight mass spectral analysis that is not instrument dependent. While spreadsheet applications such as Excel offer tremendous utility, they can be cumbersome when repeatedly performing tasks which are too complex or too user intensive for macros to be viable. To address this situation and make data analysis a faster, simpler task, our laboratory has developed a Microsoft Windows-based software program coded in Microsoft Visual Basic. This program enables the user to rapidly perform routine data analysis tasks such as mass calibration, plotting and smoothing on x- y data sets. In addition to a suite of tools for data analysis, a number of calculators are built into the software to simplify routine calculations pertaining to linear ToF-MS. These include mass resolution, ion kinetic energy and single peak identification calculators. A detailed description of the software and its associated functions is presented followed by a characterization of its performance in the analysis of several representative ToF-MS spectra obtained from different GD-ToF-MS systems.

  10. Optimizing moderator dimensions for neutron scattering at the spallation neutron source.

    Science.gov (United States)

    Zhao, J K; Robertson, J L; Herwig, Kenneth W; Gallmeier, Franz X; Riemer, Bernard W

    2013-12-01

    In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter).

  11. The Spallation Neutron Source Beam Commissioning and Initial Operations

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Stuart [Argonne National Lab. (ANL), Argonne, IL (United States); Aleksandrov, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Assadi, Saeed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bartoski, Dirk [University of Texas, Houston, TX (United States). Anderson Cancer Center; Blokland, Willem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Casagrande, F. [Michigan State Univ., East Lansing, MI (United States); Campisi, I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chu, C. [Michigan State Univ., East Lansing, MI (United States); Cousineau, Sarah M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crofford, Mark T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Danilov, Viatcheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deibele, Craig E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dodson, George W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feshenko, A. [Inst. for Nuclear Research (INR), Moscow (Russian Federation); Galambos, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Han, Baoxi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hardek, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Howell, Matthew P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jeon, D. [Inst. for Basic Science, Daejeon (Korea); Kang, Yoon W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasemir, Kay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kravchuk, L. [Institute for Nuclear Research (INR), Moscow (Russian Federation); Long, Cary D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McManamy, T. [McManamy Consulting, Inc., Middlesex, MA (United States); Pelaia, II, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Piller, Chip [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Plum, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pogge, James R. [Tennessee Technological Univ., Cookeville, TN (United States); Purcell, John David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shea, T. [European Spallation Source, Lund (Sweden); Shishlo, Andrei P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sibley, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stockli, Martin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stout, D. [Michigan State Univ., East Lansing, MI (United States); Tanke, E. [European Spallation Source, Lund (Sweden); Welton, Robert F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Y. [Michigan State Univ., East Lansing, MI (United States); Zhukov, Alexander P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

  12. Influence of the neutron transport tube on neutron resonance densitometry

    Directory of Open Access Journals (Sweden)

    Kitatani Fumito

    2017-01-01

    Full Text Available Neutron Resonance Densitometry (NRD is a non-destructive assay technique of nuclear materials in particle-like debris that contains various materials. An aim of NRD is to quantify nuclear materials in a melting fuel of Fukusima Daiichi plant, spent nuclear fuel and annihilation disposal fuel etc. NRD consists of two techniques of Neutron Resonance Transmission Analysis (NRTA and Neutron Resonance Capture Analysis (NRCA or Prompt Gamma-ray Analysis (PGA. A density of nuclear material isotopes is decided with NRTA. The materials absorbing a neutron in a wide energy range such as boron in a sample are identified by NRCA/PGA. The information of NRCA/PGA is used in NRTA analysis to quantify nuclear material isotopes. A neutron time of flight (TOF method is used in NRD measurements. A facility, consisting of a neutron source, a neutron flight path, and a detector is required. A short flight path and a strong neutron source are needed to downsize such a facility and put NRD into practical use. A neutron transport tube covers a flight path to prevent noises. In order to investigate the effect of neutron transport tube and pulse width of a neutron source, we carried out NRTA experiments with a 2-m short neutron transport tube constructed at Kyoto University Research Reactor Institute - Linear Accelerator (KURRI-LINAC, and impacts of shield of neutron transport tube and influence of pulse width of a neutron source were examined. A shield of the neutron transport tube reduced a background and had a good influence on the measurement. The resonance dips of 183W at 27 eV was successfully observed with a pulse width of a neutron source less than 2 μs.

  13. Evaluation of thermal neutron irradiation field using a cyclotron-based neutron source for alpha autoradiography.

    Science.gov (United States)

    Tanaka, H; Sakurai, Y; Suzuki, M; Masunaga, S; Mitsumoto, T; Kinashi, Y; Kondo, N; Narabayashi, M; Nakagawa, Y; Watanabe, T; Fujimoto, N; Maruhashi, A; Ono, K

    2014-06-01

    It is important to measure the microdistribution of (10)B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of (10)B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×10(9) (cm(-2)s(-1)) and an area of 40mm in diameter. In this paper, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500mg/kg of boronophenyl-alanine.

  14. Simulations towards optimization of a neutron/anti-neutron oscillation experiment at the European Spallation Source

    Science.gov (United States)

    Frost, Matthew; Kamyshkov, Yuri; Castellanos, Luis; Klinkby, Esben; US NNbar Collaboration

    2015-04-01

    The observation of Neutron/Anti-neutron oscillation would prove the existence of Baryon Number Violation (BNV), and thus an explanation for the dominance of matter over anti-matter in the universe. The latest experiments have shown the oscillation time to be greater than 8.6 x 107 seconds, whereas current theoretical predictions suggest times on the order of 108 to 109 seconds. A neutron oscillation experiment proposed at the European Spallation Source (ESS) would provide sensitivity of more than 1000 times previous experiments performed, thus providing a result well-suited to confirm or deny current theory. A conceptual design of the proposed experiment will be presented, as well as the optimization of key experiment components using Monte-Carlo simulation methods, including the McStas neutron ray-trace simulation package. This work is supported by the Organized Research Units Program funded by The University of Tennessee, Knoxville Office of Research and Engagement.

  15. The neutron distribution system of the new ultra-cold neutron source at the FRM II

    Energy Technology Data Exchange (ETDEWEB)

    Wlokka, Stephan; Frei, Andreas [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Techische Universitaet Muenchen, Lichtenbergstrasse 1, D-85747 Garching (Germany); Fierlinger, Peter; Paul, Stephan [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse 1, D-85748 Garching (Germany); Geltenbort, Peter [Institut Laue-Langevin, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2013-07-01

    Ultra-cold neutrons (UCN) are neutrons which are totally reflected from a given material surface. Typical energies of UCN are below 300 neV and velocities below 8 m/s. Thus they can be stored in material or magnetic bottles for several hundreds of seconds. As such, UCN are excellent laboratories to study fundamental parameters, e.g. the free neutron lifetime or the electric dipole moment of the neutron. The new UCN source foreseen at the FRM II will deliver high UCN densities to four experimental areas. Hence a mechanism to distribute as many UCN as possible to these areas is needed. We have developed a high efficiency UCN switch for this purpose. This talk reports about a series of measurements conducted with this switch. There have been three types of measurements, testing the transmission, storage and surface properties of the switch.

  16. A miniature laser ablation time-of-flight mass spectrometer for in situ planetary exploration

    Science.gov (United States)

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

    2003-12-01

    We report the development and testing of a miniature mass spectrometer and ion source intended to be deployed on an airless planetary surface to measure the elemental and isotopic composition of rocks and soils. Our design concentrates at this stage on the proposed BepiColombo mission to the planet Mercury. The mass analyser is an axially symmetric reflectron time-of-flight design. The ion source utilizes a laser induced plasma, which is directly coupled into the mass analyser. Laser ablation gives high spatial resolution, and avoids the need for sample preparation. Our prototype instrument has a demonstrated mass resolution m/Dgrm (FWHM) in excess of 600 and a predicted dynamic range of better than four orders of magnitude. Isotopic fractionation effects are found to be minor. We estimate that a flight instrument would have a mass of 500 g (including all electronics), a volume of 650 cm3 and could operate on 3 W power.

  17. Thick beryllium target as an epithermal neutron source for neutron capture therapy.

    Science.gov (United States)

    Wang, C K; Moore, B R

    1994-10-01

    Accelerator-based intense epithermal neutron sources for Neutron Capture Therapy (NCT) have been considered as an alternative to nuclear reactors. Lithium (Li) has generally received the widest attention for this application, since the threshold energy is low and neutron yield is high. Because of the poor thermal and chemical properties of Li and the need for heat removal in the target, the design of Li targets has been quite difficult. Beryllium (Be) has been thought of as an alternative target because of its good thermal and chemical properties and reasonable neutron yield. However, in order to have a neutron yield comparable to that of a thick Li target bombarded with 2.5 MeV protons, the proton energy required for a thick Be target must be approaching 4 MeV. Consequently, the neutrons emitted are more energetic. In addition, a significant amount of high-energy gamma rays, which is undesirable, will occur when Be is bombarded with low-energy protons. Regardless of the more energetic neutrons and additional gamma rays, in this paper it is shown that it is possible to develop a high-quality and high-intensity epithermal neutron beam based on a thick Be target for NCT treatment. For a fixed proton current, the optimal Be-target-based beam (with 4-MeV protons) can produce a neutron beam, with both quality and intensity slightly better than those produced by the optimal Li-target-based beam (with 2.5-MeV protons). The single-session NCT treatment time for the optimal Be-target-based beam is estimated to be 88 min for a proton current of 50 mA.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Neutron imaging with the short-pulse laser driven neutron source at the Trident laser facility

    Science.gov (United States)

    Guler, N.; Volegov, P.; Favalli, A.; Merrill, F. E.; Falk, K.; Jung, D.; Tybo, J. L.; Wilde, C. H.; Croft, S.; Danly, C.; Deppert, O.; Devlin, M.; Fernandez, J.; Gautier, D. C.; Geissel, M.; Haight, R.; Hamilton, C. E.; Hegelich, B. M.; Henzlova, D.; Johnson, R. P.; Schaumann, G.; Schoenberg, K.; Schollmeier, M.; Shimada, T.; Swinhoe, M. T.; Taddeucci, T.; Wender, S. A.; Wurden, G. A.; Roth, M.

    2016-10-01

    Emerging approaches to short-pulse laser-driven neutron production offer a possible gateway to compact, low cost, and intense broad spectrum sources for a wide variety of applications. They are based on energetic ions, driven by an intense short-pulse laser, interacting with a converter material to produce neutrons via breakup and nuclear reactions. Recent experiments performed with the high-contrast laser at the Trident laser facility of Los Alamos National Laboratory have demonstrated a laser-driven ion acceleration mechanism operating in the regime of relativistic transparency, featuring a volumetric laser-plasma interaction. This mechanism is distinct from previously studied ones that accelerate ions at the laser-target surface. The Trident experiments produced an intense beam of deuterons with an energy distribution extending above 100 MeV. This deuteron beam, when directed at a beryllium converter, produces a forward-directed neutron beam with ˜5 × 109 n/sr, in a single laser shot, primarily due to deuteron breakup. The neutron beam has a pulse duration on the order of a few nanoseconds with an energy distribution extending from a few hundreds of keV to almost 80 MeV. For the experiments on neutron-source spot-size measurements, our gated neutron imager was setup to select neutrons in the energy range of 2.5-35 MeV. The spot size of neutron emission at the converter was measured by two different imaging techniques, using a knife-edge and a penumbral aperture, in two different experimental campaigns. The neutron-source spot size is measured ˜1 mm for both experiments. The measurements and analysis reported here give a spatial characterization for this type of neutron source for the first time. In addition, the forward modeling performed provides an empirical estimate of the spatial characteristics of the deuteron ion-beam. These experimental observations, taken together, provide essential yet unique data to benchmark and verify theoretical work into the

  19. Recent developments in time-of-flight PET

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-02-16

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

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

    Science.gov (United States)

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

    2016-12-01

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

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

    Science.gov (United States)

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

    2011-10-01

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

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

    Science.gov (United States)

    Herrero, Federico

    2013-01-01

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

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

    Science.gov (United States)

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

    2006-01-01

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

  4. The Prompt Fission Neutron Spectrum of 235U for Einc 0.7-5.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Jaime A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haight, Robert Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Donnell, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lee, Hye Young [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taddeucci, Terry Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kelly, Keegan John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fotiadis, Nikolaos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Neudecker, Denise [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); White, Morgan Curtis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Talou, Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solomon, Clell Jeffrey Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wu, Ching-Yen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bucher, Brian Michael [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buckner, Matthew Quinn [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henderson, Roger Alan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-03-23

    The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum (PFNS) for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced using the white neutron source. Using a two arm time of flight (T.O.F) technique; Chi-Nu presents a preliminary result of the low energy component of the 235U PFNS measured using an array of 22-Lithium glass scintillators.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-03

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

  6. Electron Accelerator Shielding Design of KIPT Neutron Source Facility

    Directory of Open Access Journals (Sweden)

    Zhaopeng Zhong

    2016-06-01

    Full Text Available The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both

  7. Electron accelerator shielding design of KIPT neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhao Peng; Gohar, Yousry [Argonne National Laboratory, Argonne (United States)

    2016-06-15

    The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose

  8. High Flux Isotope Reactor cold neutron source reference design concept

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

    1998-05-01

    In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

  9. A liquid hydrocarbon deuteron source for neutron generators

    Science.gov (United States)

    Schwoebel, P. R.

    2017-06-01

    Experimental studies of a deuteron spark source for neutron generators using hydrogen isotope fusion reactions are reported. The ion source uses a spark discharge between electrodes coated with a deuterated hydrocarbon liquid, here Santovac 5, to inhibit permanent electrode erosion and extend the lifetime of high-output neutron generator spark ion sources. Thompson parabola mass spectra show that principally hydrogen and deuterium ions are extracted from the ion source. Hydrogen is the chief residual gas phase species produced due to source operation in a stainless-steel vacuum chamber. The prominent features of the optical emission spectra of the discharge are C+ lines, the hydrogen Balmer Hα-line, and the C2 Swan bands. Operation of the ion source was studied in a conventional laboratory neutron generator. The source delivered an average deuteron current of ˜0.5 A nominal to the target in a 5 μs duration pulse at 1 Hz with target voltages of -80 to -100 kV. The thickness of the hydrocarbon liquid in the spark gap and the consistency thereof from spark to spark influences the deuteron yield and plays a role in determining the beam-focusing characteristics through the applied voltage necessary to break down the spark gap. Higher breakdown voltages result in larger ion beam spots on the target and vice-versa. Because the liquid self-heals and thereby inhibits permanent electrode erosion, the liquid-based source provides long life, with 104 pulses to date, and without clear evidence that, in principle, the lifetime could not be much longer. Initial experiments suggest that an alternative cylindrical target-type generator design can extract approximately 10 times the deuteron current from the source. Preliminary data using the deuterated source liquid as a neutron-producing target are also presented.

  10. Development of nuclear design criteria for neutron spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Sordo, F.; Abanades, A. [E.T.S. Industriales, Madrid Polytechnic University, UPM, J.Gutierrez Abascal, 2 -28006 Madrid (Spain)

    2008-07-01

    Spallation neutron sources allow obtaining high neutronic flux for many scientific and industrial applications. In recent years, several proposals have been made about its use, notably the European Spallation Source (ESS), the Japanese Spallation Source (JSNS) and the projects of Accelerator-Driven Subcritical reactors (ADS), particularly in the framework of EURATOM programs. Given their interest, it seems necessary to establish adequate design basis for guiding the engineering analysis and construction projects of this kind of installations. In this sense, all works done so far seek to obtain particular solutions to a particular design, but there has not been any general development to set up an engineering methodology in this field. In the integral design of a spallation source, all relevant physical processes that may influence its behaviour must be taken into account. Neutronic aspects (emitted neutrons and their spectrum, generation performance..), thermomechanical (energy deposition, cooling conditions, stress distribution..), radiological (spallation waste activity, activation reactions and residual heat) and material properties alteration due to irradiation (atomic displacements and gas generation) must all be considered. After analysing in a systematic manner the different options available in scientific literature, the main objective of this thesis was established as making a significant contribution to determine the limiting factors of the main aspects of spallation sources, its application range and the criteria for choosing optimal materials. To achieve this goal, a series of general simulations have been completed, covering all the relevant physical processes in the neutronic and thermal-mechanical field. Finally, the obtained criteria have been applied to the particular case of the design of the spallation source of subcritical reactors PDX-ADS and XT-ADS. These two designs, developed under the European R and D Framework Program, represent nowadays

  11. Measurement of ultracold neutrons produced by using Doppler-shifted Bragg reflection at a pulsed-neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Brun, T.O.; Carpenter, J.M.; Krohn, V.E.; Ringo, G.R.; Cronin, J.W.; Dombeck, T.W.; Lynn, J.W.; Werner, S.A.

    1979-01-01

    Ultracold neutrons (UCN) have been produced at the Argonne pulsed-neutron source by the Doppler shift of 400-m/s neutrons Bragg reflected from a moving crystal. The peak density of UCN produced at the crystal exceeds 0.1 n/cm/sup 3/.

  12. Material issues relating to high power spallation neutron sources

    Science.gov (United States)

    Futakawa, M.

    2015-02-01

    Innovative researches using neutrons are being performed at the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), in which a mercury target system is installed for MW-class pulse spallation neutron sources. In order to produce neutrons by the spallation reaction, proton beams are injected into the mercury target. At the moment, when the intense proton beam hits the target, pressure waves are generated in mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel, leading to negative pressure that may cause cavitation along the vessel wall, i.e. on the interface between liquid and solid metals. On the other hand, the structural materials are subjected to irradiation damage due to protons and neutrons, very high cycle fatigue damages and so-called "liquid metal embrittlement". That is, the structural materials must be said to be exposed to the extremely severe environments. In the paper, research and development relating to the material issues in the high power spallation neutron sources that has been performed so far at J-PARC is summarized.

  13. Concept of DT fuel cycle for a fusion neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Anan' ev, S.; Spitsyn, A.V.; Kuteev, B.V.; Cherkez, D.I. [NRC Kurchatov Institute, Moscow (Russian Federation); Shirnin, P.N.; Kazakovsky, N.T. [FSUE RFNC - VNIIEF, Sarov (Russian Federation)

    2015-03-15

    A concept of DT-fusion neutron source (FNS) with the neutron yield higher than 10{sup 18} neutrons per second is under design in Russia. Such a FNS is of interest for many applications: 1) basic and applied research (neutron scattering, etc); 2) testing the structural materials for fusion reactors; 3) control of sub-critical nuclear systems and 4) nuclear waste processing (including transmutation of minor actinides). This paper describes the fuel cycle concept of a compact fusion neutron source based on a small spherical tokamak (FNS-ST) with a MW range of DT fusion power and considers the key physics issues of this device. The major and minor radii are ∼0.5 and ∼0.3 m, magnetic field ∼1.5 T, heating power less than 15 MW and plasma current 1-2 MA. The system provides the fuel mixture with equal fractions of D and T (D:T = 1:1) for all FNS technology systems. (authors)

  14. Study on induced radioactivity of China Spallation Neutron Source

    Institute of Scientific and Technical Information of China (English)

    吴青彪; 王庆斌; 吴靖民; 马忠剑

    2011-01-01

    China Spallation Neutron Source (CSNS) is the first High Energy Intense Proton Accelerator planned to be constructed in China during the State Eleventh Five-Year Plan period, whose induced radioactivity is very important for occupational disease hazard as

  15. Intense neutron source: high-voltage power supply specifications

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, A.A.

    1980-08-01

    This report explains the need for and sets forth the electrical, mechanical and safety specifications for a high-voltage power supply to be used with the intense neutron source. It contains sufficient information for a supplier to bid on such a power supply.

  16. Opportunities for Neutrino Physics at the Spallation Neutron Source (SNS)

    CERN Document Server

    Efremenko, Yu

    2008-01-01

    In this paper we discuss opportunities for a neutrino program at the Spallation Neutrons Source (SNS) being commissioning at ORNL. Possible investigations can include study of neutrino-nuclear cross sections in the energy rage important for supernova dynamics and neutrino nucleosynthesis, search for neutrino-nucleus coherent scattering, and various tests of the standard model of electro-weak interactions.

  17. Benchmarking Geant4 for spallation neutron source calculations

    Science.gov (United States)

    DiJulio, Douglas D.; Batkov, Konstantin; Stenander, John; Cherkashyna, Nataliia; Bentley, Phillip M.

    2016-09-01

    Geant4 is becoming increasingly used for radiation transport simulations of spallation neutron sources and related components. Historically, the code has seen little usage in this field and it is of general interest to investigate the suitability of Geant4 for such applications. For this purpose, we carried out Geant4 calculations based on simple spallation source geometries and also with the the European Spallation Source Technical Design Report target and moderator configuration. The results are compared to calculations performed with the Monte Carlo N- Particle extended code. The comparisons are carried out over the full spallation neutron source energy spectrum, from sub-eV energies up to thousands of MeV. Our preliminary results reveal that there is generally good agreement between the simulations using both codes. Additionally, we have also implemented a general weight-window generator for Geant4 based applications and present some results of the method applied to the ESS target model.

  18. Upgrades to the ultracold neutron source at the Los Alamos Neutron Science Center

    Science.gov (United States)

    Pattie, Robert; LANL-nEDM Collaboration

    2015-10-01

    The spallation-driven solid deutrium-based ultracold neutron (UCN) source at the Los Alamos Neutron Science Center (LANSCE) has provided a facility for precision measurements of fundamental symmetries via the decay observables from neutron beta decay for nearly a decade. In preparation for a new room temperature neutron electric dipole moment (nEDM) experiment and to increase the statistical sensitivity of all experiments using the source an effort to increase the UCN output is underway. The ultimate goal is to provide a density of 100 UCN/cc or greater in the nEDM storage cell. This upgrade includes redesign of the cold neutron moderator and UCN converter geometries, improved coupling and coating of the UCN transport system through the biological shielding, optimization of beam timing structure, and increase of the proton beam current. We will present the results of the MCNP and UCN transport simulations that led to the new design, which will be installed spring 2016, and UCN guide tests performed at LANSCE and the Institut Laue-Langevin to study the UCN transport properties of a new nickel-based guide coating.

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

    Indian Academy of Sciences (India)

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

    2000-04-01

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

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

    CERN Document Server

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

    2014-01-01

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

  1. Beer fingerprinting by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight Mass Spectrometry.

    Science.gov (United States)

    Šedo, Ondrej; Márová, Ivana; Zdráhal, Zbyněk

    2012-11-15

    A method allowing parallel fingerprinting of proteins and maltooligosaccharides directly from untreated beer samples is presented. These two classes of compounds were detected by Matrix-Assisted Laser Desorption-Ionisation-Time of Flight-Mass Spectrometry (MALDI-TOF-MS) analysis of beer mixed with 2,5-dihydroxybenzoic acid solution. The maltooligosaccharide profiles acquired from the MALDI sample spot center were not found characteristic for beers of different source and technology. On the other hand, according to profiles containing protein signals acquired from crystals formed on the border of the MALDI sample spot, we were able to distinguish beer samples of the same brand produced by different breweries. The discriminatory abilities of the method were further examined on a set of 17 lager beers, where the fingerprints containing protein signals enabled resolution of majority of examined brands. We propose MALDI-TOF-MS profiling as a rapid tool for beer brewing technology process monitoring, quality control, and determination of beer authenticity.

  2. Distance Measurement Error in Time-of-Flight Sensors Due to Shot Noise

    Science.gov (United States)

    Illade-Quinteiro, Julio; Brea, Víctor M.; López, Paula; Cabello, Diego; Doménech-Asensi, Gines

    2015-01-01

    Unlike other noise sources, which can be reduced or eliminated by different signal processing techniques, shot noise is an ever-present noise component in any imaging system. In this paper, we present an in-depth study of the impact of shot noise on time-of-flight sensors in terms of the error introduced in the distance estimation. The paper addresses the effect of parameters, such as the size of the photosensor, the background and signal power or the integration time, and the resulting design trade-offs. The study is demonstrated with different numerical examples, which show that, in general, the phase shift determination technique with two background measurements approach is the most suitable for pixel arrays of large resolution. PMID:25723141

  3. Distance Measurement Error in Time-of-Flight Sensors Due to Shot Noise

    Directory of Open Access Journals (Sweden)

    Julio Illade-Quinteiro

    2015-02-01

    Full Text Available Unlike other noise sources, which can be reduced or eliminated by different signal processing techniques, shot noise is an ever-present noise component in any imaging system. In this paper, we present an in-depth study of the impact of shot noise on time-of-flight sensors in terms of the error introduced in the distance estimation. The paper addresses the effect of parameters, such as the size of the photosensor, the background and signal power or the integration time, and the resulting design trade-offs. The study is demonstrated with different numerical examples, which show that, in general, the phase shift determination technique with two background measurements approach is the most suitable for pixel arrays of large resolution.

  4. Heavy ion time-of-flight ERDA of high dose metal implanted germanium

    Energy Technology Data Exchange (ETDEWEB)

    Dytlewski, N.; Evans, P.J.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Bunder, J. [New South Wales Univ., Wollongong, NSW (Australia). Wollongong Univ. Coll

    1996-12-31

    With the thick Ge substrates used in ion implantation, RBS can have difficulty in resolving the mass-depth ambiguities when analysing materials composed of mixtures of elements with nearly equal masses. Additional, and complimentary techniques are thus required. This paper reports the use of heavy ion time-of-flight elastic recoil detection analysis (ToF- ERDA), and conventional RBS in the analysis of Ge(100) implanted with high dose Ti and Cu ions from a MEWA ion source . Heavy ion ToF ERDA has been used to resolve, and profile the implanted transition metal species, and also to study any oxygen incorporation into the sample resulting from the implantation, or subsequential reactions with air or moisture. This work is part of a study on high dose metal ion implantation of medium atomic weight semiconductor materials. 13 refs., 6 figs.

  5. TOFwave: reproducibility in biomarker discovery from time-of-flight mass spectrometry data.

    Science.gov (United States)

    Chierici, Marco; Albanese, Davide; Franceschi, Pietro; Furlanello, Cesare

    2012-11-01

    Many are the sources of variability that can affect reproducibility of disease biomarkers from time-of-flight (TOF) Mass Spectrometry (MS) data. Here we present TOFwave, a complete software pipeline for TOF-MS biomarker identification, that limits the impact of parameter tuning along the whole chain of preprocessing and model selection modules. Peak profiles are obtained by a preprocessing based on Continuous Wavelet Transform (CWT), coupled with a machine learning protocol aimed at avoiding selection bias effects. Only two parameters (minimum peak width and a signal to noise cutoff) have to be explicitly set. The TOFwave pipeline is built on top of the mlpy Python package. Examples on Matrix-Assisted Laser Desorption and Ionization (MALDI) TOF datasets are presented. Software prototype, datasets and details to replicate results in this paper can be found at http://mlpy.sf.net/tofwave/.

  6. A Proposal for a Next Generation European Neutron Source

    Science.gov (United States)

    Andersen, K. H.; Carlile, C. J.

    2016-09-01

    We argue that it is not too early to begin the planning process for a next generation neutron source for Europe, even as the European Spallation Source is being constructed. We put forward three main arguments. Firstly, nowadays the period between the first scientific concept of a new facility being proposed and its actual realisation is approaching half a century. We show evidence for this. Secondly, there is a straightforward development of the short pulse/long pulse spallation concepts that will deliver gains in neutron brightness of more than a factor 30 over what the ESS will soon deliver and provide the optimum balance between resolution and intensity. We describe our concept, which is a spallation source where the proton pulse length is matched to the moderating time of slow neutrons. Thirdly, when we look at our colleagues in astronomy and high energy physics, we see that they have a totally different, more global and more ambitious approach to the coming generations of large facilities. We argue that it is time for the neutron community not simply to rest upon its laurels and take what is given but to be proactive..

  7. Measurement of neutron flux and beam divergence at the cold neutron guide system of the new Munich research reactor FRM-II

    Science.gov (United States)

    Zeitelhack, K.; Schanzer, C.; Kastenmüller, A.; Röhrmoser, A.; Daniel, C.; Franke, J.; Gutsmiedl, E.; Kudryashov, V.; Maier, D.; Päthe, D.; Petry, W.; Schöffel, T.; Schreckenbach, K.; Urban, A.; Wildgruber, U.

    2006-05-01

    A sophisticated neutron guide system has been installed at the new Munich neutron source FRM-II to transport neutrons from the D 2 cold neutron source to several instruments, which are situated in a separate neutron guide hall. The guide system takes advantage of supermirror coatings and includes a worldwide unique "twisted" guide for a desired phase space transformation of the neutron beam. During the initial reactor commissioning in summer 2004, the integral and differential neutron flux as well as the distribution of beam divergence at the exit of two representative and the twisted neutron guide were measured using time-of-flight spectroscopy and gold-foil activation. The experimental results can be compared to extensive simulation calculations based on MCNP and McStas. The investigated guides fulfill the expectations of providing high neutron fluxes and reveal good quality with respect to the reflective coatings and the installation precision.

  8. Measurement of neutron flux and beam divergence at the cold neutron guide system of the new Munich research reactor FRM-II

    Energy Technology Data Exchange (ETDEWEB)

    Zeitelhack, K. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany)]. E-mail: karl.zeitelhack@frm2.tum.de; Schanzer, C. [Physik-Department E21, TU Muenchen, D-85747 Garching (Germany); Kastenmueller, A. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Roehrmoser, A. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Daniel, C. [Physik-Department E22, TU Muenchen, D-85747 Garching (Germany); Franke, J. [Max-Planck-Institut fuer Metallforschung, D-70569 Stuttgart (Germany); Gutsmiedl, E. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Kudryashov, V. [GKSS Forschungszentrum GmbH, D-21502 Geesthacht (Germany); Maier, D. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Paethe, D. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Petry, W. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Schoeffel, T. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Schreckenbach, K. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Urban, A. [ZWE FRM-II, TU Muenchen, D-85747 Garching (Germany); Wildgruber, U. [Max-Planck-Institut fuer Metallforschung, D-70569 Stuttgart (Germany)

    2006-05-10

    A sophisticated neutron guide system has been installed at the new Munich neutron source FRM-II to transport neutrons from the D{sub 2} cold neutron source to several instruments, which are situated in a separate neutron guide hall. The guide system takes advantage of supermirror coatings and includes a worldwide unique 'twisted' guide for a desired phase space transformation of the neutron beam. During the initial reactor commissioning in summer 2004, the integral and differential neutron flux as well as the distribution of beam divergence at the exit of two representative and the twisted neutron guide were measured using time-of-flight spectroscopy and gold-foil activation. The experimental results can be compared to extensive simulation calculations based on MCNP and McStas. The investigated guides fulfill the expectations of providing high neutron fluxes and reveal good quality with respect to the reflective coatings and the installation precision.

  9. Rectification of the OPAL Cold Neutron Source Cryogenic System

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Weijian [Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2013-07-01

    The Cold Neutron Source (CNS) at ANSTO's OPAL Reactor had experienced repeated outages since 2009 due to failures in the cryogenic system. An extensive root cause analysis was initiated in May 2012, led by an ANSTO team that also involved knowledgeable external experts. At the conclusion of the investigation, a set of recommendations was released to address the identified contributing causes. A rectification program was established to implement the solutions. Cryogenic operation of the CNS, providing end users with cold neutrons, successfully returned to service in July 2013. Thanks to the unique stand-by operation mode of the CNS, irradiation activities at the reactor, as well as thermal neutron availability, had not been affected during the year-long investigation/rectification process. Some technical and operational aspects of the investigation, testing and engineering modifications are discussed in this presentation.

  10. Development of grazing incidence devices for space-borne time of flight mass spectrometry

    Science.gov (United States)

    Cadu, A.; Devoto, P.; Louarn, P.; Sauvaud, J.-A.

    2012-04-01

    Time of flight mass spectrometer is widely used to study space plasmas in planetary and solar missions. This space-borne instrument selects ions in function of their energy through an electrostatic analyzer. Particles are then post-accelerated to energies in the range of 20 keV to cross a carbon foil. At the foil exit, electrons are emitted and separated from ion beam in the time of flight section. A first detector (a Micro-Channel Plate or MCP) emits a start signal at electron arrival and a second one emits a stop signal at incident ion end of path. The time difference gives the speed of the particle and its mass can be calculated, knowing its initial energy. However, current instruments suffer from strong limitations. The post acceleration needs very high voltage power supplies which are heavy, have a high power consumption and imply technical constraints for the development. A typical instrument weighs from 5 to 6 kg, includes a 20 kV power supply, consumes a least 5 W and encounters corona effect and electrical breakdown problems. Moreover, despite the particle high energy range, scattering and straggling phenomena in the carbon foil significantly reduce the instrument overall resolution. Some methods, such as electrostatic focus lenses or reflectrons, really improve mass separation but global system efficiency remains very low because of the charge state dependence of such devices. The main purpose of our work is to replace carbon foil by grazing incidence MCP's - also known as MPO's, for Micro Pore Optics - for electron emission. Thus, incident particles would back-scatter onto the channel inner surface with an angle of a few degrees. With this solution, we can decrease dispersion sources and lower the power supplies to post accelerate ions. The result would be a lighter and simpler instrument with a substantial resolution improvement. We have first simulated MPO's behavior with TRIM and MARLOWE Monte-Carlo codes. Energy scattering and output angle computed

  11. Measuring and monitoring KIPT Neutron Source Facility Reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yan [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States); Zhong, Zhaopeng [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-08-01

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on developing and constructing a neutron source facility at Kharkov, Ukraine. The facility consists of an accelerator-driven subcritical system. The accelerator has a 100 kW electron beam using 100 MeV electrons. The subcritical assembly has keff less than 0.98. To ensure the safe operation of this neutron source facility, the reactivity of the subcritical core has to be accurately determined and continuously monitored. A technique which combines the area-ratio method and the flux-to-current ratio method is purposed to determine the reactivity of the KIPT subcritical assembly at various conditions. In particular, the area-ratio method can determine the absolute reactivity of the subcritical assembly in units of dollars by performing pulsed-neutron experiments. It provides reference reactivities for the flux-to-current ratio method to track and monitor the reactivity deviations from the reference state while the facility is at other operation modes. Monte Carlo simulations are performed to simulate both methods using the numerical model of the KIPT subcritical assembly. It is found that the reactivities obtained from both the area-ratio method and the flux-to-current ratio method are spatially dependent on the neutron detector locations and types. Numerical simulations also suggest optimal neutron detector locations to minimize the spatial effects in the flux-to-current ratio method. The spatial correction factors are calculated using Monte Carlo methods for both measuring methods at the selected neutron detector locations. Monte Carlo simulations are also performed to verify the accuracy of the flux-to-current ratio method in monitoring the reactivity swing during a fuel burnup cycle.

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

    CERN Document Server

    Schury, P; Wada, M; Wollnik, H

    2013-01-01

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

  13. Crystal timing offset calibration method for time of flight PET scanners

    Science.gov (United States)

    Ye, Jinghan; Song, Xiyun

    2016-03-01

    In time-of-flight (TOF) positron emission tomography (PET), precise calibration of the timing offset of each crystal of a PET scanner is essential. Conventionally this calibration requires a specially designed tool just for this purpose. In this study a method that uses a planar source to measure the crystal timing offsets (CTO) is developed. The method uses list mode acquisitions of a planar source placed at multiple orientations inside the PET scanner field-of-view (FOV). The placement of the planar source in each acquisition is automatically figured out from the measured data, so that a fixture for exactly placing the source is not required. The expected coincidence time difference for each detected list mode event can be found from the planar source placement and the detector geometry. A deviation of the measured time difference from the expected one is due to CTO of the two crystals. The least squared solution of the CTO is found iteratively using the list mode events. The effectiveness of the crystal timing calibration method is evidenced using phantom images generated by placing back each list mode event into the image space with the timing offset applied to each event. The zigzagged outlines of the phantoms in the images become smooth after the crystal timing calibration is applied. In conclusion, a crystal timing calibration method is developed. The method uses multiple list mode acquisitions of a planar source to find the least squared solution of crystal timing offsets.

  14. Neutron activation analysis: Modelling studies to improve the neutron flux of Americium–Beryllium source

    Directory of Open Access Journals (Sweden)

    Abdessamad Didi

    2017-06-01

    Full Text Available Americium–beryllium (Am-Be; n, γ is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences. It is a mobile source of neutron activity (20 Ci, yielding a small thermal neutron flux that is water moderated. The aim of this study is to develop a model to increase the neutron thermal flux of a source such as Am-Be. This study achieved multiple advantageous results: primarily, it will help us perform neutron activation analysis. Next, it will give us the opportunity to produce radio-elements with short half-lives. Am-Be single and multisource (5 sources experiments were performed within an irradiation facility with a paraffin moderator. The resulting models mainly increase the thermal neutron flux compared to the traditional method with water moderator.

  15. Measurement of uranium and plutonium in solid waste by passive photon or neutron counting and isotopic neutron source interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Crane, T.W.

    1980-03-01

    A summary of the status and applicability of nondestructive assay (NDA) techniques for the measurement of uranium and plutonium in 55-gal barrels of solid waste is reported. The NDA techniques reviewed include passive gamma-ray and x-ray counting with scintillator, solid state, and proportional gas photon detectors, passive neutron counting, and active neutron interrogation with neutron and gamma-ray counting. The active neutron interrogation methods are limited to those employing isotopic neutron sources. Three generic neutron sources (alpha-n, photoneutron, and /sup 252/Cf) are considered. The neutron detectors reviewed for both prompt and delayed fission neutron detection with the above sources include thermal (/sup 3/He, /sup 10/BF/sub 3/) and recoil (/sup 4/He, CH/sub 4/) proportional gas detectors and liquid and plastic scintillator detectors. The instrument found to be best suited for low-level measurements (< 10 nCi/g) is the /sup 252/Cf Shuffler. The measurement technique consists of passive neutron counting followed by cyclic activation using a /sup 252/Cf source and delayed neutron counting with the source withdrawn. It is recommended that a waste assay station composed of a /sup 252/Cf Shuffler, a gamma-ray scanner, and a screening station be tested and evaluated at a nuclear waste site. 34 figures, 15 tables.

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

    Science.gov (United States)

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

    2014-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

  18. Design of a High Intensity Neutron Source for Neutron-Induced Fission Yield Studies

    CERN Document Server

    Lantz, M; Jokinen, A; Kolhinen, V S; Mattera, A; Penttilä, H; Pomp, S; Rakopoulos, V; Rinta-Antila, S; Solders, A

    2013-01-01

    The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyv\\"askyl\\"a, has been supplied with a new cyclotron which will provide protons of the order of 100 {\\mu}A with up to 30 MeV energy, or deuterons with half the energy and intensity. This makes it an ideal place for measurements of neutron-induced fission products from various actinides, in view of proposed future nuclear fuel cycles. The groups at Uppsala University and University of Jyv\\"askyl\\"a are working on the design of a neutron converter that will be used as neutron source in fission yield studies. The design is based on simulations with Monte Carlo codes and a benchmark measurement that was recently performed at The Svedberg Laboratory in Uppsala. In order to obtain a competitive count rate the fission targets will be placed very close to the neutron converter. The goal is to have a flexible design that will enable the use of neutron fields with different energy distributions. In the present paper, some co...

  19. Neutrons production on the IPHI accelerator for the validation of the design of the compact neutron source SONATE

    CERN Document Server

    Menelle, Alain; Prunes, Fabien; Homatter, Benoit; Annighöfer, Burkhard; Porcher, Florence; Chauvin, Nicolas; Schwindling, Jérôme; Letourneau, Alain; Marchix, Anthony; Tran, Ngoc-Hoang

    2016-01-01

    We aim at building an accelerator based compact neutron source which would provide a thermal neutron flux on the order of 4E12 n.s-1.cm-2.sr-1. Such brilliance would put compact neutron sources on par with existing medium flux neutron research reactors. We performed the first neutron production tests on the IPHI proton accelerator at Saclay. The neutron fluxes were measured using gold foil activation and 3He detectors. The measured fluxes were compared with MCNP and GEANT4 Monte Carlo simulations in which the whole experimental setup was modelled. There is a good agreement between the experimental measurements and the Monte-Carlo simulations. The available modelling tools will allow us to optimize the whole Target Moderator Reflector assembly together with the neutron scattering spectrometer geometries.

  20. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    Science.gov (United States)

    Schooneveld, E. M.; Pietropaolo, A.; Andreani, C.; Perelli Cippo, E.; Rhodes, N. J.; Senesi, R.; Tardocchi, M.; Gorini, G.

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  1. Energy-dispersive study of the interactions of fast neutrons with matter

    CERN Document Server

    Altstadt, E; Eckert, S; Freiesleben, H; Galindo, V; Grosse, E; Naumann, B; Weiss, F P

    2003-01-01

    The construction and the first use of a compact time-of-flight system for the energy-dispersive study of the interaction of fast neutrons with materials are content of a network project of the Research Center Rossendorf, to which also the Technical University Dresden contributes in the framework of a common DFG project. The planned time-of-flight experiments with pulsed neutrons will be performed at the radiation source ELBE. First results on the development of a neutron-production target are presented. By means of radiation-transport and finite-element programs the distributions of the energy deposition of the used pulsed electron beam of the radiation source ELBE and the temperature in the neutron radiator as well as the expected particle spectra and fluxes at the measurement place were calculated. Considerations on the development of a beam catcher are discussed.

  2. A transportable neutron radiography system based on a SbBe neutron source

    Science.gov (United States)

    Fantidis, J. G.; Nicolaou, G. E.; Tsagas, N. F.

    2009-07-01

    A transportable neutron radiography system, incorporating a SbBe neutron source, has been simulated using the MCNPX code. Design provisions have allowed two radiography systems to be utilised using the same SbBe neutron source. In this respect, neutron radiographies can be carried out using the photoneutrons produced when the 124Sb is surrounded by the Be target. Alternatively, γ-radiography can be utilised with the photons from the 124Sb with the target removed. Appropriate collimators were simulated for each of the radiography modes. Apart from Be, the materials considered were compatible with the European Union Directive on 'Restriction of Hazardous Substances' (RoHS) 2002/95/EC, hence excluding the use of cadmium and lead. Bismuth was chosen as the material for γ-radiation shielding and the proposed system allowed a maximum activity of the 124Sb up to 1.85×1013 Bq. The system simulated allows different object sizes to be studied with a wide range of radiography parameters.

  3. Material recognition with a 252Cf source

    CERN Document Server

    Fabris, Daniela; Lunardon, Marcello; Moretto, Sandra; Nebbia, Giancarlo; Pesente, Silvia; Stevanato , Luca; Viesti, Giuseppe; Sajo-Bohusb, Laszlo

    2010-01-01

    Material recognition is studied by measuring simultaneously the transmission of neutron and gamma rays produced by a time-tagged 252Cf source. Light elements (C,N,O) are identified by using the measured transmission versus neutron time of flight. The yield of the transmitted gamma ray as a function of energy provides high precision identification of the atomic number of the sample up to Z=83 . A tomography system, currently under construction, is described.

  4. Characterization of a Be(p,xn) neutron source for fission yields measurements

    CERN Document Server

    Mattera, A; Hjalmarsson, A; Lantz, M; Pomp, S; Rakopoulos, V; Solders, A; Valldor-Blücher, J; Gorelov, D; Penttilä, H; Rinta-Antila, S; Prokofiev, A V; Passoth, E; Bedogni, R; Gentile, A; Bortot, D; Esposito, A; Introini, M V; Pola, A

    2013-01-01

    We report on measurements performed at The Svedberg Laboratory (TSL) to characterize a proton-neutron converter for independent fission yield studies at the IGISOL-JYFLTRAP facility (Jyv\\"askyl\\"a, Finland). A 30 MeV proton beam impinged on a 5 mm water-cooled Beryllium target. Two independent experimental techniques have been used to measure the neutron spectrum: a Time of Flight (TOF) system used to estimate the high-energy contribution, and a Bonner Sphere Spectrometer able to provide precise results from thermal energies up to 20 MeV. An overlap between the energy regions covered by the two systems will permit a cross-check of the results from the different techniques. In this paper, the measurement and analysis techniques will be presented together with some preliminary results.

  5. Time-Reversal Invariance Violation in Neutron Scattering at Spallation Neutron Sources

    Science.gov (United States)

    Gudkov, Vladimir

    2014-09-01

    The Time Reversal Invariant Violating (TRIV) effects in neutron transmission through a nuclei target are discussed. We explore the possibility to search TRIV at new high flux Spallation Neutron Sources using two important advantages of neutron nuclei interactions: the possibility of an enhancement of T-violating observables by many orders of magnitude, and the relatively large number of the nuclear targets, which provides the assurance of avoiding possible ``accidental'' cancelations of TRI-violating effects due to unknown structural factors related to the strong interactions. This include the absence of final state interactions for a set of specific observables, the possibility to avoid of false asymmetries arising from combinations of time-reversal-invariant interactions and asymmetries in real experiment, and the comparison of expected results with existing limits on neutron, nuclear and atomic electric dipole moments (EDMs). It is shown that TRIV observables are complementary to the EDM experiments and have potential for essential improving of the current limits on the TRIV interactions. The Time Reversal Invariant Violating (TRIV) effects in neutron transmission through a nuclei target are discussed. We explore the possibility to search TRIV at new high flux Spallation Neutron Sources using two important advantages of neutron nuclei interactions: the possibility of an enhancement of T-violating observables by many orders of magnitude, and the relatively large number of the nuclear targets, which provides the assurance of avoiding possible ``accidental'' cancelations of TRI-violating effects due to unknown structural factors related to the strong interactions. This include the absence of final state interactions for a set of specific observables, the possibility to avoid of false asymmetries arising from combinations of time-reversal-invariant interactions and asymmetries in real experiment, and the comparison of expected results with existing limits on neutron

  6. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  7. Initial thermal characterization of the Cornell cold neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Spern, S.A.; Atwood, A.G.; Clark, D.D.; Hossain, T.Z. [Cornell Univ., Ithaca, NY (United States)

    1995-12-31

    The completed full-scale Cornell cold neutron source, an integral component of the Cornell cold neutron beam facility, has undergone testing prior to its insertion (and consequent activation) in the Cornell 500-kW TRIGA reactor. The source consists of an organic moderator (mesitylene) contained within an aluminum chamber, which is cooled by conduction through a 99.999+ pure 1.90-cm-diam copper rod 267 cm long, coupled to the second (4-W capacity), cooler stage of a helium cryorefrigerator. Approximately 18 h is required to achieve equilibrium chamber temperatures. To lower the radiational T 4 load on the second stage, the chamber and rod are surrounded by an active heat shield, consisting of 99.99+ pure copper (oxygen-free high conductivity) coupled to the first 60-W capacity stage of the cryorefrigerator. Other components include the associated mesitylene handling system (MHS) and vacuum system.

  8. China Experimental Fast Reactor(CEFR)——Criterion of Criticality for Reactor With External Neutron Source

    Institute of Scientific and Technical Information of China (English)

    ZHAOYu-sen

    2003-01-01

    There is a neutron source with 109 s-1 neutrons in core of CEFR during start up test and operation of CEFR. For judging the criticality of reactor with external neutron source and near criticality, it is important that the neutron level changes in core with time must be understood after introducing positive reactivity to core with external neutron source.

  9. Analysis of fuel management in the KIPT neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhong Zhaopeng, E-mail: zzhong@anl.gov [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Gohar, Yousry; Talamo, Alberto [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2011-05-15

    Research highlights: > Fuel management of KIPT ADS was analyzed. > Core arrangement was shuffled in stage wise. > New fuel assemblies was added into core periodically. > Beryllium reflector could also be utilized to increase the fuel life. - Abstract: Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of an experimental neutron source facility consisting of an electron accelerator driven sub-critical assembly. The neutron source driving the sub-critical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The sub-critical assembly surrounding the target is fueled with low enriched WWR-M2 type hexagonal fuel assemblies. The U-235 enrichment of the fuel material is <20%. The facility will be utilized for basic and applied research, producing medical isotopes, and training young specialists. With the 100 KW electron beam power, the total thermal power of the facility is {approx}360 kW including the fission power of {approx}260 kW. The burnup of the fissile materials and the buildup of fission products continuously reduce the system reactivity during the operation, decrease the neutron flux level, and consequently impact the facility performance. To preserve the neutron flux level during the operation, the fuel assemblies should be added and shuffled for compensating the lost reactivity caused by burnup. Beryllium reflector could also be utilized to increase the fuel life time in the sub-critical core. This paper studies the fuel cycles and shuffling schemes of the fuel assemblies of the sub-critical assembly to preserve the system reactivity and the neutron flux level during the operation.

  10. Obsidian sources characterized by neutron-activation analysis.

    Science.gov (United States)

    Gordus, A A; Wright, G A; Griffin, J B

    1968-07-26

    Concentrations of elements such as manganese, scandium, lanthanum, rubidium, samarium, barium, and zirconium in obsidian samples from different flows show ranges of 1000 percent or more, whereas the variation in element content in obsidian samples from a single flow appears to be less than 40 percent. Neutron-activation analysis of these elements, as well as of sodium and iron, provides a means of identifying the geologic source of an archeological artifact of obsidian.

  11. Electron Accelerator Shielding Design of KIPT Neutron Source Facility

    OpenAIRE

    Zhaopeng Zhong; Yousry Gohar

    2016-01-01

    The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nu...

  12. Actinide/beryllium neutron sources with reduced dispersion characteristics

    Science.gov (United States)

    Schulte, Louis D.

    2012-08-14

    Neutron source comprising a composite, said composite comprising crystals comprising BeO and AmBe.sub.13, and an excess of beryllium, wherein the crystals have an average size of less than 2 microns; the size distribution of the crystals is less than 2 microns; and the beryllium is present in a 7-fold to a 75-fold excess by weight of the amount of AmBe.sub.13; and methods of making thereof.

  13. General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy

    Science.gov (United States)

    Bosko, Andrey

    This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular among nuclear pharmacies and clinics in many countries; it is compact and reliable; it produces protons with energies high enough to produce neutrons with appropriate energy and fluence rate for BNCT and it does not require significant changes in design to provide neutrons. In particular, the standard PETtrace 18O target is considered. The cyclotron efficiency may be significantly increased if unused neutrons produced during radioisotopes production could be utilized for other medical modalities such as BNCT at the same time. The resulting dose from the radiation emitted from the target is evaluated using the Monte Carlo radiation transport code MCNP at several depths in a brain phantom for different scattering geometries. Four different moderating materials of various thicknesses were considered: light water, carbon, heavy water, arid Fluental(TM). The fluence rate tally was used to calculate photon and neutron dose, by applying fluence rate-to-dose conversion factors. Fifteen different geometries were considered and a 30-cm thick heavy water moderator was chosen as the most suitable for BNCT with the GE PETtrace cyclotron. According to the Brookhaven Medical Research Reactor (BMRR) protocol, the maximum dose to the normal brain is set to 12.5 RBEGy, which for the conditions of using a heavy water moderator, assuming a 60 muA beam current, would be reached with a treatment time of 258 min. Results showed that using a PETtrace cyclotron in this configuration provides a therapeutic ratio of about 2.4 for depths up to 4 cm inside a brain phantom. Further increase of beam current proposed by GE should significantly improve the beam quality or the treatment time and allow treating tumors at greater depths.

  14. Oak Ridge Spallation Neutron Source (ORSNS) target station design integration

    Energy Technology Data Exchange (ETDEWEB)

    McManamy, T.; Booth, R.; Cleaves, J.; Gabriel, T. [and others

    1996-06-01

    The conceptual design for a 1- to 3-MW short pulse spallation source with a liquid mercury target has been started recently. The design tools and methods being developed to define requirements, integrate the work, and provide early cost guidance will be presented with a summary of the current target station design status. The initial design point was selected with performance and cost estimate projections by a systems code. This code was developed recently using cost estimates from the Brookhaven Pulsed Spallation Neutron Source study and experience from the Advanced Neutron Source Project`s conceptual design. It will be updated and improved as the design develops. Performance was characterized by a simplified figure of merit based on a ratio of neutron production to costs. A work breakdown structure was developed, with simplified systems diagrams used to define interfaces and system responsibilities. A risk assessment method was used to identify potential problems, to identify required research and development (R&D), and to aid contingency development. Preliminary 3-D models of the target station are being used to develop remote maintenance concepts and to estimate costs.

  15. Colliding Neutron Stars as the Source of Heavy Elements

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Where do the heavy elements the chemical elements beyond iron in our universe come from? One of the primary candidate sources is the merger of two neutron stars, but recent observations have cast doubt on this model. Can neutron-star mergers really be responsible?Elements from Collisions?Periodic table showing the origin of each chemical element. Those produced by the r-process are shaded orange and attributed to supernovae in this image; though supernovae are one proposed source of r-process elements, an alternative source is the merger of two neutron stars. [Cmglee]When a binary-neutron-star system inspirals and the two neutron stars smash into each other, a shower of neutrons are released. These neutrons are thought to bombard the surrounding atoms, rapidly producing heavy elements in what is known as r-process nucleosynthesis.So could these mergers be responsible for producing the majority of the universes heavy r-process elements? Proponents of this model argue that its supported by observations. The overall amount of heavy r-process material in the Milky Way, for instance, is consistent with the expected ejection amounts from mergers, based both on predicted merger rates for neutron stars in the galaxy, and on the observed rates of soft gamma-ray bursts (which are thought to accompany double-neutron-star mergers).Challenges from Ultra-Faint DwarfsRecently, however, r-process elements have been observed in ultra-faint dwarf satellite galaxies. This discovery raises two major challenges to the merger model for heavy-element production:When neutron stars are born during a core-collapse supernova, mass is ejected, providing the stars with asymmetric natal kicks. During the second collapse in a double-neutron-star binary, wouldnt the kick exceed the low escape velocity of an ultra-faint dwarf, ejecting the binary before it could merge and enrich the galaxy?Ultra-faint dwarfs have very old stellar populations and the observation of r-process elements in these stars

  16. Advanced Neutron Source: Plant Design Requirements. Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

  17. Advanced Neutron Source: Plant Design Requirements. Revision 4

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

  18. Methods for lipid nanostructure investigation at neutron and synchrotron sources

    Science.gov (United States)

    Kiselev, M. A.

    2011-03-01

    A lipid membrane is a main component of biological membranes. Contemporary bionanotechnologies use phospholipids and ceramides as basic components of drugs and cosmetic preparations. Phospholipids-based nanoparticles are used as drug carriers. Effective development of bionanotechnologies in Russia calls for creation of physical methods to diagnose the particle nanostructure which would be promising for application in pharmacology. Radiation with wavelengths of 1-10 Å is an adequate instrument for detecting the nanostructure of lipid bi- and monolayers. The review deals with methods that apply neutron scattering and synchrotron radiation for studying nanostructures of lipid membranes, phospholipid nanoparticles, and phospholipid monolayers on a water surface by techniques of diffraction, small-angle scattering, and reflectometry. The importance of the mutually complementary application of neutron and synchrotron radiation for solving urgent problems of membrane biophysics, microbiology, dermapharmacology, and bionanotechnologies is demonstrated by particular examples of studies of phospholipid membranes and ceramide-based membranes. The efficiency of development and application of new methods for solving urgent problems of biophysics is shown. The review is written on the basis of results obtained over the period of 1999-2010 at the Joint Institute for Nuclear Research (JINR) Laboratory of Neutron Physics in collaboration with the Pharmaceutical Departments of universities of France (Paris-Sud, Chatenay Malabry) and Germany (Martin Luther University, Halle). The experiments were performed at various European and Russian neutron and synchrotron sources.

  19. Characterization of compact accelerator DD neutron source for in situ calibration experiment on neutron measurement at LHD

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Yasunari; Iguchi, Tetsuo; Ogata, Tomohiro; Umemura, Norihiro; Asai, Keisuke; Kawarabayashi, Jun [Nagoya Univ., Nagoya, Aichi (Japan); Sasao, Mamiko [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2003-07-01

    A compact Cockcroft-Walton type accelerator DD neutron source has been developed for in situ calibration experiments on neutron measurements at LHD. The equipment mainly consists of three parts; a deuterium (D) reservoir/ion source, a self-loaded deuterium target and a 100 kV high voltage power supply, all of which are contained in a compact cylindrical stainless steel (SUS) tube of 70 mm in diameter and 780 mm in length. About one hour steady operation was performed under the acceleration voltage of 80 keV and the ion beam current of {approx}60 {mu}A, corresponding to the DD neutron yield of around 10{sup 5} n/s. The neutron emission profile and energy spectrum were measured with an NE213 scintillator and a {sup 3}He gas proportional counter. Preliminary neutronic calculations with a Monte Carlo neutron transport code MCNP' were also executed for simulating the in situ calibration experiment for neutron detectors that will be installed on LHD. Through the experiments and the calculations, it is shown that the present DD neutron source is valid for in situ calibration on threshold type detectors used for neutron emission profile monitoring and neutron spectrometry at DD plasma experiments. (author)

  20. Plant model of KIPT neutron source facility simulator

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yan [Argonne National Lab. (ANL), Argonne, IL (United States); Wei, Thomas Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Grelle, Austin L. [Argonne National Lab. (ANL), Argonne, IL (United States); Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-02-01

    Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine are collaborating on constructing a neutron source facility at KIPT, Kharkov, Ukraine. The facility has 100-kW electron beam driving a subcritical assembly (SCA). The electron beam interacts with a natural uranium target or a tungsten target to generate neutrons, and deposits its power in the target zone. The total fission power generated in SCA is about 300 kW. Two primary cooling loops are designed to remove 100-kW and 300-kW from the target zone and the SCA, respectively. A secondary cooling system is coupled with the primary cooling system to dispose of the generated heat outside the facility buildings to the atmosphere. In addition, the electron accelerator has a low efficiency for generating the electron beam, which uses another secondary cooling loop to remove the generated heat from the accelerator primary cooling loop. One of the main functions the KIPT neutron source facility is to train young nuclear specialists; therefore, ANL has developed the KIPT Neutron Source Facility Simulator for this function. In this simulator, a Plant Control System and a Plant Protection System were developed to perform proper control and to provide automatic protection against unsafe and improper operation of the facility during the steady-state and the transient states using a facility plant model. This report focuses on describing the physics of the plant model and provides several test cases to demonstrate its capabilities. The plant facility model uses the PYTHON script language. It is consistent with the computer language of the plant control system. It is easy to integrate with the simulator without an additional interface, and it is able to simulate the transients of the cooling systems with system control variables changing on real-time.

  1. Neutron sources and its dosimetric characteristics; Fuentes de neutrones y sus caracteristicas dosimetricas

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A. [Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico); Gallego D, E.; Lorente F, A. [Universidad Politecnica de Madrid, C/Jose Gutierrez Abascal 2, E-28006 Madrid (Spain)

    2005-07-01

    By means of Monte Carlo methods the spectra of the produced neutrons {sup 252} Cf, {sup 252} Cf/D{sub 2}O, {sup 241} Am Be, {sup 239} Pu Be, {sup 140} La Be, {sup 239} Pu{sup 18}O{sub 2} and {sup 226} Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H{sup *}(10), H{sub p,sIab} (10, 0{sup 0}), E{sub AP} and E{sub ISO}. During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of {sup 239} Pu Be and {sup 241} Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

  2. Design Optimization and the path towards a 2 MW Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; J. Wei; W. Weng; S. Zhang; J. Billen; S. Kurennoy; S. Nath; J. Stovall; H. Takeda; L. Young; R. Keller; J. Staples; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; D. Jeon; S. Kim; R. Kustom; E. Tanke; W. Wan; R. Sundelin

    2001-08-01

    The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source.

  3. Tomsk Polytechnic University cyclotron as a source for neutron based cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lisin, V. A. [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation); Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 (Russian Federation); Bogdanov, A. V.; Golovkov, V. M.; Sukhikh, L. G.; Verigin, D. A., E-mail: verigin@tpu.ru [Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 (Russian Federation); Musabaeva, L. I. [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation)

    2014-02-15

    In this paper we present our cyclotron based neutron source with average energy 6.3 MeV generated during the 13.6 MeV deuterons interactions with beryllium target, neutron field dosimetry, and dosimetry of attendant gamma fields. We also present application of our neutron source for cancer treatment.

  4. Fission neutron spectra measurements at LANSCE - status and plans

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory; Noda, Shusaku [Los Alamos National Laboratory; Nelson, Ronald O [Los Alamos National Laboratory; O' Donnell, John M [Los Alamos National Laboratory; Devlin, Matt [Los Alamos National Laboratory; Chatillon, Audrey [CEA-FRANCE; Granier, Thierry [CEA-FRANCE; Taieb, Julien [CEA-FRANCE; Laurent, Benoit [CEA-FRANCE; Belier, Gilbert [CEA-FRANCE; Becker, John A [LLNL; Wu, Ching - Yen [LLNL

    2009-01-01

    A program to measure fission neutron spectra from neutron-induced fission of actinides is underway at the Los Alamos Neutron Science Center (LANSCE) in a collaboration among the CEA laboratory at Bruyeres-le-Chatel, Lawrence Livermore National Laboratory and Los Alamos National Laboratory. The spallation source of fast neutrons at LANSCE is used to provide incident neutron energies from less than 1 MeV to 100 MeV or higher. The fission events take place in a gas-ionization fission chamber, and the time of flight from the neutron source to that chamber gives the energy of the incident neutron. Outgoing neutrons are detected by an array of organic liquid scintillator neutron detectors, and their energies are deduced from the time of flight from the fission chamber to the neutron detector. Measurements have been made of the fission neutrons from fission of {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. The range of outgoing energies measured so far is from 1 MeV to approximately 8 MeV. These partial spectra and average fission neutron energies are compared with evaluated data and with models of fission neutron emission. Results to date will be presented and a discussion of uncertainties will be given in this presentation. Future plans are to make significant improvements in the fission chambers, neutron detectors, signal processing, data acquisition and the experimental environment to provide high fidelity data including mea urements of fission neutrons below 1 MeV and improvements in the data above 8 MeV.

  5. Modeling of water radiolysis at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Daemen, L.L.; Kanner, G.S.; Lillard, R.S.; Butt, D.P.; Brun, T.O.; Sommer, W.F.

    1998-12-01

    In spallation neutron sources neutrons are produced when a beam of high-energy particles (e.g., 1 GeV protons) collides with a (water-cooled) heavy metal target such as tungsten. The resulting spallation reactions produce a complex radiation environment (which differs from typical conditions at fission and fusion reactors) leading to the radiolysis of water molecules. Most water radiolysis products are short-lived but extremely reactive. When formed in the vicinity of the target surface they can react with metal atoms, thereby contributing to target corrosion. The authors will describe the results of calculations and experiments performed at Los Alamos to determine the impact on target corrosion of water radiolysis in the spallation radiation environment. The computational methodology relies on the use of the Los Alamos radiation transport code, LAHET, to determine the radiation environment, and the AEA code, FACSIMILE, to model reaction-diffusion processes.

  6. A SEARCH FOR POINT SOURCES OF EeV NEUTRONS

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, P.; Andringa, S. [LIP and Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Aglietta, M. [Istituto di Fisica dello Spazio Interplanetario (INAF), Universita di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Albuquerque, I. F. M. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Allard, D. [Laboratoire AstroParticule et Cosmologie (APC), Universite Paris 7, CNRS-IN2P3, Paris (France); Allekotte, I. [Centro Atomico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Facultad Regional Buenos Aires, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Alvarez Castillo, J. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico); Alvarez-Muniz, J. [Universidad de Santiago de Compostela (Spain); Alves Batista, R. [IFGW, Universidade Estadual de Campinas, Campinas, SP (Brazil); Ambrosio, M.; Aramo, C. [Universita di Napoli ' Federico II' and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Antici' c, T. [Rudjer Boskovi' c Institute, 10000 Zagreb (Croatia); Arganda, E. [IFLP, Universidad Nacional de La Plata and CONICET, La Plata (Argentina); Collaboration: Pierre Auger Collaboration; and others

    2012-12-01

    A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from -90 Degree-Sign to +15 Degree-Sign in declination using four different energy ranges above 1 EeV (10{sup 18} eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.

  7. Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aymond, F. [Univ. of Texas at Austin, TX (United States); Bridgewater, Jon S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deppert, O. [Technische Universitat Darmstadt (Germany); Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Falk, Katerina [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fernandez, Juan Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gautier, Donald Cort [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gonzales, Manuel A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goodsell, Alison Victoria [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Guler, Nevzat [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hamilton, Christopher Eric [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hegelich, Bjorn Manuel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henzlova, Daniela [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ianakiev, Kiril Dimitrov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Iliev, Metodi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Randall Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jung, Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kleinschmidt, Annika [Technische Universitat Darmstadt (Germany); Koehler, Katrina Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pomerantz, Ishay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roth, Markus [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Santi, Peter Angelo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shimada, Tsutomu [Los Alamos National Laboratory; Swinhoe, Martyn Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taddeucci, Terry Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wurden, Glen Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Palaniyappan, Sasikumar [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); McCary, E. [Univ. of Texas at Austin, TX (United States)

    2015-01-28

    Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

  8. Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source

    CERN Document Server

    Hannaske, Roland; Beyer, Roland; Junghans, Arnd; Bemmerer, Daniel; Birgersson, Evert; Ferrari, Anna; Grosse, Eckart; Kempe, Mathias; Kögler, Toni; Marta, Michele; Massarczyk, Ralph; Matic, Andrija; Schramm, Georg; Schwengner, Ronald; Wagner, Andreas

    2014-01-01

    Neutron total cross sections of 197 Au and nat Ta have been measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV with a statistical uncertainty of up to 2 % and a total systematic uncertainty of 1 %. This facility is optimized for the fast neutron energy range and combines an excellent t ime structure of the neutron pulses (electron bunch width 5 ps) with a short flight path of 7 m. Because of the low instantaneous neutron flux transmission measurements of neutron total cross sections are possible, that exhibit very different beam and back ground conditions than found at other neutron sources.

  9. Neutron total cross section measurements of gold and tantalum at the nELBE photoneutron source

    CERN Document Server

    Hannaske, Roland; Beyer, Roland; Junghans, Arnd; Bemmerer, Daniel; Birgersson, Evert; Ferrari, Anna; Grosse, Eckart; Kempe, Mathias; Kögler, Toni; Marta, Michele; Massarczyk, Ralph; Matic, Andrija; Schramm, Georg; Schwengner, Ronald; Wagner, Andreas

    2013-01-01

    Neutron total cross sections of $^{197}$Au and $^\\text{nat}$Ta have been measured at the nELBE photoneutron source in the energy range from 0.1 - 10 MeV with a statistical uncertainty of up to 2 % and a total systematic uncertainty of 1 %. This facility is optimized for the fast neutron energy range and combines an excellent time structure of the neutron pulses (electron bunch width 5 ps) with a short flight path of 7 m. Because of the low instantaneous neutron flux transmission measurements of neutron total cross sections are possible, that exhibit very different beam and background conditions than found at other neutron sources.

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

    Data.gov (United States)

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

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

    Science.gov (United States)

    Pluciński, Jerzy

    2006-02-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  13. Neutron imaging data processing using the Mantid framework

    Science.gov (United States)

    Pouzols, Federico M.; Draper, Nicholas; Nagella, Sri; Yang, Erica; Sajid, Ahmed; Ross, Derek; Ritchie, Brian; Hill, John; Burca, Genoveva; Minniti, Triestino; Moreton-Smith, Christopher; Kockelmann, Winfried

    2016-09-01

    Several imaging instruments are currently being constructed at neutron sources around the world. The Mantid software project provides an extensible framework that supports high-performance computing for data manipulation, analysis and visualisation of scientific data. At ISIS, IMAT (Imaging and Materials Science & Engineering) will offer unique time-of-flight neutron imaging techniques which impose several software requirements to control the data reduction and analysis. Here we outline the extensions currently being added to Mantid to provide specific support for neutron imaging requirements.

  14. Event-based processing of neutron scattering data

    Science.gov (United States)

    Peterson, Peter F.; Campbell, Stuart I.; Reuter, Michael A.; Taylor, Russell J.; Zikovsky, Janik

    2015-12-01

    Many of the world's time-of-flight spallation neutrons sources are migrating to recording individual neutron events. This provides for new opportunities in data processing, the least of which is to filter the events based on correlating them with logs of sample environment and other ancillary equipment. This paper will describe techniques for processing neutron scattering data acquired in event mode which preserve event information all the way to a final spectrum, including any necessary corrections or normalizations. This results in smaller final uncertainties compared to traditional methods, while significantly reducing processing time and memory requirements in typical experiments. Results with traditional histogramming techniques will be shown for comparison.

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

    Science.gov (United States)

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

    2004-05-01

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

  16. Validation of a qualitative screening method for pesticides in fruits and vegetables by gas chromatography quadrupole-time of flight mass spectrometry with atmospheric pressure chemical ionization

    NARCIS (Netherlands)

    Portoles, T.; Mol, J.G.J.; Sancho, J.V.; Lopez, F.J.; Hernandez, F.

    2014-01-01

    A wide-scope screening method was developed for the detection of pesticides in fruit and vegetables. The method was based on gas chromatography coupled to a hybrid quadrupole time-of-flight mass spectrometer with an atmospheric pressure chemical ionization source (GC-(APCI)QTOF MS). A non-target acq

  17. Monte Carlo simulation of neutron scattering instruments

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, P.A.

    1995-12-31

    A library of Monte Carlo subroutines has been developed for the purpose of design of neutron scattering instruments. Using small-angle scattering as an example, the philosophy and structure of the library are described and the programs are used to compare instruments at continuous wave (CW) and long-pulse spallation source (LPSS) neutron facilities. The Monte Carlo results give a count-rate gain of a factor between 2 and 4 using time-of-flight analysis. This is comparable to scaling arguments based on the ratio of wavelength bandwidth to resolution width.

  18. Linear electric field time-of-flight ion mass spectrometer

    Science.gov (United States)

    Funsten, Herbert O.; Feldman, William C.

    2008-06-10

    A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

  19. Effect of Fusion Neutron Source Numerical Models on Neutron Wall Loading in a D-D Tokamak Device

    Institute of Scientific and Technical Information of China (English)

    陈义学; 吴宜灿

    2003-01-01

    Effect of various spatial and energy distributions of fusion neutron source on the calculation of neutron wall loading of Tokamak D-D fusion device has been investigated by means of the 3-D Monte Carlo code MCNP. A realistic Monte Carlo source model was developed based on the accurate representation of the spatial distribution and energy spectrum of fusion neutrons to solve the complicated problem of tokamak fusion neutron source modelling. The results show that those simplified source models will introduce significant uncertainties. For accurate estimation of the key nuclear responses of the tokamak design and analyses, the use of the realistic source is recommended. In addition, the accumulation of tritium produced during D-D plasma operation should be carefully considered.

  20. Lithium target for accelerator based BNCT neutron source: Influence by the proton irradiation on lithium

    Science.gov (United States)

    Fujii, R.; Imahori, Y.; Nakakmura, M.; Takada, M.; Kamada, S.; Hamano, T.; Hoshi, M.; Sato, H.; Itami, J.; Abe, Y.; Fuse, M.

    2012-12-01

    The neutron source for Boron Neutron Capture Therapy (BNCT) is in the transition stage from nuclear reactor to accelerator based neutron source. Generation of low energy neutron can be achieved by 7Li (p, n) 7Be reaction using accelerator based neutron source. Development of small-scale and safe neutron source is within reach. The melting point of lithium that is used for the target is low, and durability is questioned for an extended use at a high current proton beam. In order to test its durability, we have irradiated lithium with proton beam at the same level as the actual current density, and found no deterioration after 3 hours of continuous irradiation. As a result, it is suggested that lithium target can withstand proton irradiation at high current, confirming suitability as accelerator based neutron source for BNCT.