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Sample records for scintillation neutron spectrometer

  1. Neutron spectrometer using NE218 liquid scintillator

    International Nuclear Information System (INIS)

    Dance, J.B.; Francois, P.E.

    1976-01-01

    A neutron spectrometer has been constructed using NE218 liquid scintillator. Discrimination against electron-gamma events was obtained usng a charge-comparison pulse shape discrimination system. The resolution obtained was about 0.25 MeV F.W.H.M. at 2.0 MeV

  2. High-pressure 3He gas scintillation neutron spectrometer

    International Nuclear Information System (INIS)

    Derzon, M.S.; Slaughter, D.R.; Prussin, S.G.

    1985-10-01

    A high-pressure, 3 He-Xe gas scintillation spectrometer has been developed for neutron spectroscopy on D-D fusion plasmas. The spectrometer exhibits an energy resolution of (121 +- 20 keV) keV (FWHM) at 2.5 MeV and an efficiency of (1.9 +- 0.4) x 10 -3 (n/cm 2 ) -1 . The contribution to the resolution (FWHM) from counting statistics is only (22 +- 3 keV) and the remainder is due predominantly to the variation of light collection efficiency with location of neutron events within the active volume of the detector

  3. Fast neutron scintillation spectrometer in a heavy ion accelerator

    International Nuclear Information System (INIS)

    Blinov, M.V.; Gavrilov, B.P.; Ivannikova, L.L.; Kozulin, Eh.M.; Mozhaev, A.N.; Tyurin, G.P.

    1984-01-01

    Scintillation fast neutron spectrometer in a heavy ion accelerator is described in short. The spectrometer is used to measure characteristics of neutrons emitted in heavy ion interaction with different nuclei. Experiment was performed on the base of particle flight from 0.7 up to 2 m. Within the angle range of 0-150 deg. The technique is based on recording of two-dimensional neutron spectra obtained due to combination of the time-of-flight method and the method of recoil proton energy detection. Two measuring channels were used in the spectrometer. Each channel comprise both amplitude and time tracks. Detector on the base microchannel plates (MCP) generated a signal in passing the next ion bunch was used in order to obtain the time mark. Data from the scintillation block are recorded with respect to three parameters: recoil proton amplitude, time of neutron or γ-quantum arrival in respect of MCP-sensor pulse. Apparatus is carried out within the CAMAC standard. The spectrometer calibration within the 1-20 MeV neutron range was conducted in the Van-de-Graaf accelerator, and for higher energies - with the use of lightguides. Spectrometer time resolution for neutron energies of 0.5-50 MeV constituted 1.5-1.8 ns. The above measuring of neutron spectra from 1 /H2C+ 181 Ta and sup(20, 22)Ne+sup(181)Ta reaction have revealed a possibility of the experiment organization in heavy ion accelerators in the presence of strong neutron and γ-fields. Organization of multi-dimensional analysis combining two methods allows one to separate accelerator cycle, a region of the most reliable information, free of a low-energy gamma background and limited both by a dynamic threshold and a region of permissible energy values

  4. Wide-range scintillation spectrometer of fast neutrons

    International Nuclear Information System (INIS)

    Blinov, M.V.; Gavrilov, B.P.; Ivannikova, L.L.; Kozulin, Eh.M.; Mozhaev, A.N.; Saidgareev, V.M.; Tyurin, G.P.

    1984-01-01

    A spectrometer of fast neutrons developed on the base of stilbene crystas and permitting to detect neutrons simultaneously by time-of-flight and recoil protons with analysis of pulse shape in the 0.5-50 MeV energy range is described. The detecting part is performed in the CAMAC standard. The ''Minsk-32'' computer was used for data storage and preliminary processing

  5. An organic scintillator neutron spectrometer suitable for in-phantom studies

    International Nuclear Information System (INIS)

    Harrison, K.G.

    1981-07-01

    A transportable organic scintillator spectrometry system based on a 1 cm high x 1 cm dia. cylindrical stilbene scintillator with a 30 cm light-pipe has been developed for neutron spectrometry inside anthropomorphic phantoms in order to improve knowledge of dose and dose-equivalent distributions in the body. Electronic pulse-shape discrimination is used to discriminate between neutron and gamma-ray events in the scintillator. The spectrometer is shown to give excellent results in the range of neutron energies from 1.5 to 7 MeV when used with an unfolding program based on differentiation of the pulse-height distribution. Below 1 MeV problems are experienced with pulse-shape discrimination, and below 2 MeV there are found to be some shortcomings in the differentiation method for this size of scintillator. Above about 9 MeV more sophisticated unfolding methods are shown to be desirable. Problems of stability of the system, difficulties in the measurement and calculation of the response functions, and disadvantages of using stilbene are discussed. (author)

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

    Science.gov (United States)

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

    2015-03-01

    The use of high-energy (> 8 MeV) 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 neutron beam contamination. The neutron spectrum in a hospital environment is usually measured with integrating detectors such as bubble dosimeters, Thermo Luminescent Dosimeters (TLDs) or Bonner Spheres, which integrate the information over a time interval and an energy one. This paper presents the development of a neutron spectrometer based on the Time of Flight (ToF) technique in order to perform a real time characterization of the neutron contamination. The detector measures the neutron spectrum exploiting the fact that the LINAC beams are pulsed and arranged in bunches with a rate of 100-300 Hz depending on the beam type and energy. The detector consists of boron loaded scintillating fibers readout by a MultiAnode PhotoMultiplier Tube (MAPMT). A detailed description of the detector and the acquisition system together with the results in terms of ToF spectra and number of neutrons with a Varian Clinac iX are presented.

  7. Using the transportable, computer-operated, liquid-scintillator fast-neutron spectrometer system

    International Nuclear Information System (INIS)

    Thorngate, J.H.

    1988-01-01

    When a detailed energy spectrum is needed for radiation-protection measurements from approximately 1 MeV up to several tens of MeV, organic-liquid scintillators make good neutron spectrometers. However, such a spectrometer requires a sophisticated electronics system and a computer to reduce the spectrum from the recorded data. Recently, we added a Nuclear Instrument Module (NIM) multichannel analyzer and a lap-top computer to the NIM electronics we have used for several years. The result is a transportable fast-neutron spectrometer system. The computer was programmed to guide the user through setting up the system, calibrating the spectrometer, measuring the spectrum, and reducing the data. Measurements can be made over three energy ranges, 0.6--2 MeV, 1.1--8 MeV, or 1.6--16 MeV, with the spectrum presented in 0.1-MeV increments. Results can be stored on a disk, presented in a table, and shown in graphical form. 5 refs., 51 figs

  8. A gamma scintillation spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Symbalisty, S

    1952-07-01

    A scintillation type gamma ray spectrometer employing coincidence counting, designed and built at the Physics Department of the University of Western Ontario is described. The spectrometer is composed of two anthracene and photomultiplier radiation detectors, two pulse analyzing channels, a coincidence stage, three scalers and a high voltage stabilized supply. A preliminary experiment to test the operation of the spectrometer was performed and the results of this test are presented. (author)

  9. A large neutron missing mass spectrometer using long plastic scintillators with electronical determination of the neutron interaction point

    International Nuclear Information System (INIS)

    Apel, W.D.; Mueller, H.; Schinzel, D.; Sigurdsson, G.; Staudenmaier, H.M.; Stier, U.

    1975-11-01

    A large acceptance and high efficiency neutron detector is described. The sensitive area and volume of the detector is 3.07 m 2 and 1.03 m 3 respectively. The detector consists of sixteen elements of plastic scintillator, each having the dimensions (16 x 16 x 240) cm 3 . The mean detection efficiency is about 33% for neutrons of 100-500 MeV/c momentum. An interesting feature of this instrument is the accuracy achieved in locating incident particles, which is +-3 cm for charged particles and +-4 cm for neutrons. The accuracy achieved for the time-of-flight measurement is +-1 nsec for fast neutrons. (orig.) [de

  10. Charged particle scintillation mass spectrometer

    International Nuclear Information System (INIS)

    Baranov, P.S.; Zhuravlev, E.E.; Nafikov, A.A.; Osadchi , A.I.; Raevskij, V.G.; Smirnov, P.A.; Cherepnya, S.N.; Yanulis, Yu.P.

    1982-01-01

    A scintillation mass-spectrometer for charged particle identification by the measured values of time-of-flight and energy operating on line with the D-116 computer is described. Original time detectors with 100x100x2 mm 3 and 200x2 mm 2 scintillators located on the 1- or 2 m path length are used in the spectrometer. The 200x200x200 mm 3 scintillation unit is used as a E-counter. Time-of-flight spectra of the detected particles on the 2 m path length obtained in spectrometer test in the beam of charged particles escaping from the carbon target at the angle of 130 deg under 1.2 GeV bremsstrahlung beam of the ''Pakhra'' PIAS synchrotron are presented. Proton and deuteron energy spectra as well as mass spectrum of all the particles detected by the spectrometer are given. Mass resolution obtained on the 2 m path length for π-mesons is +-25%, for protons is +-5%, for deuterons is +-3%

  11. Design of A HPGe-Plastic Scintillator Compton Suppression Spectrometer for Neutron Activation Analysis and Radio environmental Studies

    International Nuclear Information System (INIS)

    Sharshar, T.; Badran, H.; Elnimr, T.

    1998-01-01

    The design of a compton suppression spectrometer consisting of a 10% p-type HPGe detector and an annular anti-Compton shield made of N E-102 A plastic scintillator is described. The height of the guard plastic- scintillation detector was optimized experimentally using a NaI(Ti) ring, consisting of five NaI(Ti) detectors. The annular guard detector is divided to four optically isolated quarters to enhance the light collection. Each quarter of the guard detector was tested and satisfying results are obtained

  12. Neutron crosstalk between liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, J.M., E-mail: verbeke2@llnl.gov; Prasad, M.K., E-mail: prasad1@llnl.gov; Snyderman, N.J., E-mail: snyderman1@llnl.gov

    2015-09-11

    A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction.

  13. Neutron crosstalk between liquid scintillators

    International Nuclear Information System (INIS)

    Verbeke, J.M.; Prasad, M.K.; Snyderman, N.J.

    2015-01-01

    A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction

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

    Energy Technology Data Exchange (ETDEWEB)

    Sayre, D. B., E-mail: sayre4@llnl.gov; Barbosa, F.; Caggiano, J. A.; Eckart, M. J.; Grim, G. P.; Hartouni, E. P.; Hatarik, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); DiPuccio, V. N.; Weber, F. A. [National Security Technologies, Livermore, California 94551 (United States)

    2016-11-15

    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.

  15. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

    2000-01-01

    The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

  16. Prototype Neutron Energy Spectrometer

    International Nuclear Information System (INIS)

    Mitchell, Stephen; Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald

    2010-01-01

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production (ship effect), (a, n) reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  17. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production [ship effect], [a, n] reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  18. Hybrid scintillators for neutron discrimination

    Science.gov (United States)

    Feng, Patrick L; Cordaro, Joseph G; Anstey, Mitchell R; Morales, Alfredo M

    2015-05-12

    A composition capable of producing a unique scintillation response to neutrons and gamma rays, comprising (i) at least one surfactant; (ii) a polar hydrogen-bonding solvent; and (iii) at least one luminophore. A method including combining at least one surfactant, a polar hydrogen-bonding solvent and at least one luminophore in a scintillation cell under vacuum or an inert atmosphere.

  19. Development of Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Lee, J. S.; Seong, B. S. (and others)

    2007-06-15

    Neutron spectrometers which are used in the basic researches such as physics, chemistry and materials science and applied in the industry were developed at the horizontal beam port of HANARO reactor. In addition, the development of core components for neutron scattering and the upgrade of existing facilities are also performed. The vertical neutron reflectometer was fabricated and installed at ST3 beam port. The performance test of the reflectometer was completed and the reflectometer was opened to users. The several core parts and options were added in the polarized neutron spectrometer. The horizontal neutron reflectometer from Brookhaven National Laboratory was moved to HANARO and installed, and the performance of the reflectometer was examined. The HIPD was developed and the performance test was completed. The base shielding for TAS was fabricated. The soller collimator, Cu mosaic monochromator, Si BPC monochromator and position sensitive detector were developed and applied in the neutron spectrometer as part of core component development activities. In addition, the sputtering machine for mirror device are fabricated and the neutron mirror is made using the sputtering machine. The FCD was upgraded and the performance of the FCD are improved over the factor of 10. The integration and upgrade of the neutron detection system were also performed.

  20. Electron volt neutron spectrometers

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Senesi, R.

    2011-01-01

    The advent of pulsed neutron sources has made available intense fluxes of epithermal neutrons (500 meV ≤E≤100 eV ). The possibility to open new investigations on condensed matter with eV neutron scattering techniques, is related to the development of methods, concepts and devices that drive, or are inspired by, emerging studies at this energy scale. Electron volt spectrometers have undergone continuous improvements since the construction of the first prototype instruments, but in the last decade major breakthroughs have been accomplished in terms of resolution and counting statistics, leading, for example, to the direct measurement of the proton 3-D Born–Oppenheimer potential in any material, or to quantitatively probe nuclear quantum effects in hydrogen bonded systems. This paper reports on the most effective methods and concepts for energy analysis and detection, as well as devices for the optimization of electron volt spectrometers for different applications. This is set in the context of the progress made up to date in instrument development. Starting from early stages of development of the technique, particular emphasis will be given to the Vesuvio eV spectrometer at the ISIS neutron source, the first spectrometer where extensive scientific, as well as research and development programmes have been carried out. The potential offered by this type of instrumentation, from single particle excitations to momentum distribution studies, is then put in perspective into the emerging fields of eV spectroscopy applied to cultural heritages and neutron irradiation effects in electronics. - Highlights: ► Neutron spectrometers at eV energies. ► Methods and techniques for eV neutrons counting at spallation sources. ► Scattering, imaging and radiation hardness tests with multi-eV neutrons.

  1. Neutrons detection by scintillation; Detection de neutrons par scintillations

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-01-15

    The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

  2. Neutrons detection by scintillation; Detection de neutrons par scintillations

    Energy Technology Data Exchange (ETDEWEB)

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

    1955-01-15

    The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

  3. Neutron spectrometer for improved SNM search.

    Energy Technology Data Exchange (ETDEWEB)

    Vance, Andrew L.; Aigeldinger, Georg

    2007-03-01

    With the exception of large laboratory devices with very low sensitivities, a neutron spectrometer have not been built for fission neutrons such as those emitted by special nuclear materials (SNM). The goal of this work was to use a technique known as Capture Gated Neutron Spectrometry to develop a solid-state device with this functionality. This required modifications to trans-stilbene, a known solid-state scintillator. To provide a neutron capture signal we added lithium to this material. This unique triggering signal allowed identification of neutrons that lose all of their energy in the detector, eliminating uncertainties that arise due to partial energy depositions. We successfully implemented a capture gated neutron spectrometer and were able to distinguish an SNM like fission spectrum from a spectrum stemming from a benign neutron source.

  4. Scintillating fibre tracking neutron detector

    International Nuclear Information System (INIS)

    Karlsson, Joakim.

    1995-04-01

    A detector for measurements of collimated fluxes of neutrons in the energy range 2-20 MeV is proposed. It utilizes (n.p) elastic scattering in scintillating optical fibres placed in successive orthogonal layers perpendicular to the neutron flux. A test module has been designed, constructed and tested with respect to separation of neutron and gamma events. The pulse height measurements show the feasibility to discriminate between neutron, gamma and background events. Application to measurements of fusion neutrons is considered. 18 refs, 22 figs, 4 tabs

  5. Application of modular neutron spectrometer to measure neutron spectra from fission of 252Cf

    International Nuclear Information System (INIS)

    Szeflinski, Z.; Osuch, S.; Popkiewicz, M.; Wilhelmi, Z.; Zelazny, Z.

    1996-01-01

    The neutron spectrometer MONA (Modular Neutron Array) and its test has been described. The spectrometers consist of eight BC-501A liquid scintillator detectors of BICRON which allow one to distinguish between the pulses from gamma quanta and neutrons using pulse shape discrimination (PSD) method. The electronic equipment for the PSD and the test result using the 252 Cf radioactive source are presented

  6. Detailed investigation of a time-of-flight neutron spectrometer

    International Nuclear Information System (INIS)

    Elevant, T.; Trostell, B.

    1981-02-01

    Properties of a neutron spectrometer and telescope, based on double neutron interaction in hydrogen based scintillators and neutron time-of-flight technique, have been investigated in detail. Theoretical scaling of the resolutions with the flight path length and scattering angle have been confirmed by experimental results. Important parameters in connection with calibration of the spectrometer are discussed and calculated relative resolutions of the ion temperature are shown when applied to a fusion deuterium plasma. (Auth.)

  7. An Advanced Neutron Spectrometer for Future Manned Exploration Missions

    Science.gov (United States)

    Christl, Mark; Apple, Jeffrey A.; Cox, Mark D.; Dietz, Kurtis L.; Dobson, Christopher C.; Gibson, Brian F.; Howard, David E.; Jackson, Amanda C.; Kayatin, Mathew J.; Kuznetsov, Evgeny N.; hide

    2014-01-01

    An Advanced Neutron Spectrometer (ANS) is being developed to support future manned exploration missions. This new instrument uses a refined gate and capture technique that significantly improves the identification of neutrons in mixed radiation fields found in spacecraft, habitats and on planetary surfaces. The new instrument is a composite scintillator comprised of PVT loaded with litium-6 glass scintillators. We will describe the detection concept and show preliminary results from laboratory tests and exposures at particle accelerators

  8. Background characterization in a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Rodriguez Barquero, L.; Los Arcos, J.M.; Jimenez de Mingo, A.

    1995-01-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0 - 20 KeV, 0 - 800 KeV and 0 - 2 MeV, for volume between 2 and 20 mi of three commercial scintillators, Hisafe II, Ultima-Gold and Instagel, and quenching degree in the interval equivalent to 50% - 3% tritium efficiency. This procedure was tested with standard samples of 3H, and led to average discrepancies less than 10% for activity ≥0,6 Bq, against conventional methods for which the discrepancies are twice on average. (Author) 10 refs

  9. Background characterization in a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Rodriguez Barquero, L.; Los arcos, J.M.; Jimenez de Mingo, A.

    1995-01-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0-20 KeV, 0-800 KeV and 0-2 MeV, for volume between 2 and 20 ml of three commercial scintillators, Hisafe II, Ultima-gold and Instagel, and quenching degree in the interval equivalent to 50%-3% tritium efficiency. This procedure was tested with standard samples of ''3 H, and led to average discrepancies less than 10% for activity => 0,6 Bq, against conventional methods for which the discrepancies are twice on average

  10. Neutron spectra measuring by magnetless hadron spectrometer

    International Nuclear Information System (INIS)

    Bayukov, Yu.D.; Buklej, A.E.; Gavrilov, V.B.

    1980-01-01

    The energy resolution, efficiency and background conditions of neutron recording in inclusive nuclear reactions by a magnetless hadron spectrometer (MHS) in the 8-300 MeV energy range. The scheme of apparatus lay-out for measuring neutron recording efficiency is shown. For recording colliding particles with the 3 GeV/c momentum four beam scintillation counters, the latter of which of 30x40 mm dimensions and 1 mm thickness defines the working beam range in the target centre, are used. Targets of the 80 mm diameter made of C and Pb (2.08 g/cm 2 and 3.04 g/cm 2 thickness, respectively) are located at the 45 deg angle in respect to the beam direction. Secondary particles escaping at the 90 deg angle are recorded by two telescopes of the scintillation counters. For neutron and γ quanta recording the special scintillation detector of the 20 cm thickness encircled by an anticoincidence counter is used. The neutron recording efficiency is determined on the basis of comparison of the neutron production differential cross sections of the π +- 12 C 6 → nX reactions and of proton production in isotopically symmetric reactions π +- 12 C 6 → pX. The experimental data are in good agreement with the calculation data [ru

  11. Automatic detection of recoil-proton tracks and background rejection criteria in liquid scintillator-micro-capillary-array fast neutron spectrometer

    Science.gov (United States)

    Mor, Ilan; Vartsky, David; Dangendorf, Volker; Tittelmeier, Kai.; Weierganz, Mathias; Goldberg, Mark Benjamin; Bar, Doron; Brandis, Michal

    2018-06-01

    We describe an analysis procedure for automatic unambiguous detection of fast-neutron-induced recoil proton tracks in a micro-capillary array filled with organic liquid scintillator. The detector is viewed by an intensified CCD camera. This imaging neutron detector possesses the capability to perform high position-resolution (few tens of μm), energy-dispersive transmission-imaging using ns-pulsed beams. However, when operated with CW or DC beams, it also features medium-quality spectroscopic capabilities for incident neutrons in the energy range 2-20 MeV. In addition to the recoil proton events which display a continuous extended track structure, the raw images exhibit complex ion-tracks from nuclear interactions of fast-neutrons in the scintillator, capillaries quartz-matrix and CCD. Moreover, as expected, one also observes a multitude of isolated scintillation spots of varying intensity (henceforth denoted "blobs") that originate from several different sources, such as: fragmented proton tracks, gamma-rays, heavy-ion reactions as well as events and noise that occur in the image-intensifier and CCD. In order to identify the continuous-track recoil proton events and distinguish them from all these background events, a rapid, computerized and automatic track-recognition-procedure was developed. Based on an appropriately weighted analysis of track parameters such as: length, width, area and overall light intensity, the method is capable of distinguishing a single continuous-track recoil proton from typically surrounding several thousands of background events that are found in each CCD frame.

  12. Light response of YAP:Ce and LaBr{sub 3}:Ce scintillators to 4–30 MeV protons for applications to Telescope Proton Recoil neutron spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Cazzaniga, C., E-mail: carlo.cazzaniga@stfc.ac.uk [ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Istituto di Fisica del Plasma “P. Caldirola”, Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano (Italy); Cremona, A. [Istituto di Fisica del Plasma “P. Caldirola”, Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano (Italy); Nocente, M.; Rebai, M.; Rigamonti, D. [Istituto di Fisica del Plasma “P. Caldirola”, Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano (Italy); Università degli Studi di Milano-Bicocca, Dipartimento di Fisica, Piazza della Scienza 3, Milano (Italy); Tardocchi, M. [Istituto di Fisica del Plasma “P. Caldirola”, Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano (Italy); Croci, G. [Istituto di Fisica del Plasma “P. Caldirola”, Associazione EURATOM-ENEA/CNR, Via Cozzi 53, Milano (Italy); Università degli Studi di Milano-Bicocca, Dipartimento di Fisica, Piazza della Scienza 3, Milano (Italy); Ericsson, G. [Department of Physics and Astronomy, EURATOM-VR Association, Uppsala University, Uppsala (Sweden); Fazzi, A. [Department of Energy of the Politecnico di Milano, via Lambruschini 4, I-20156 Milano (Italy); Hjalmarsson, A. [Department of Physics and Astronomy, EURATOM-VR Association, Uppsala University, Uppsala (Sweden); Mazzocco, M.; Strano, E. [Dipartimento di Fisica e Astronomia, Universitá di Padova, and INFN, Sez. di Padova, I-35131 Padova (Italy); and others

    2016-06-01

    The light response of two thin inorganic scintillators based on YAP:Ce and LaBr{sub 3}:Ce crystals has been measured with protons in the 4–8 MeV energy range at the Uppsala tandem accelerator and in the 8–26 MeV energy range at the Legnaro tandem accelerator. The crystals have been calibrated in situ with {sup 137}Cs and {sup 60}Co γ-ray sources. The relative light yields of protons with respect to gammas have been measured and are here reported to be (96±2)% and (80±2)% for YAP:Ce and LaBr{sub 3}:Ce, respectively. The results open up to the development of a Telescope Proton Recoil spectrometer based on either of the two crystals as alternative to a silicon based spectrometer for applications to high neutron fluxes.

  13. Neutron spectrometry with the NE-213 organic scintillator detector

    International Nuclear Information System (INIS)

    Silva, A.A. da.

    1980-12-01

    A neutron spectrometer with the NE-213 organic scintillator detector (5,08cm x 5,08cm) was mounted, tested, and calibrated at the Argonaut Reactor Laboratory of the Instituto de Engenharia Nuclear, to measure and study spectra of available fast neutron sources. The time zero-crossover technique was employed to discriminate the pulse of neutrons and gammas. The neutron spectrum from a 241 Am-Be source was determined experimentally in the range 1,0 MeV to 12,0 MeV and good agreement with other researchers was obtained. (Author) [pt

  14. Borehole instrument for scintillation gamma spectrometer

    International Nuclear Information System (INIS)

    Sinitsyn, A.Ya.; Gabitov, R.M.

    1979-01-01

    Described are a schematic diagram and main specifications of a borehole instrument with autostabilization of energy scale measure by gamma bench-mark of 137 Cs, intended for the application in a logging gamma spectrometer to determine separately the concentrations of nature radioactive elements. The instrument may be connected to the KOBDFM-2 cable of 600 m length. It contains a scintillation counter for gamma quanta consisting of 30x70 mm NaI(Tl) crystal and a FEU-85 photoamplifier, an input conforming stage, a diagram of threshold pulse formation and regulating high-voltage generator. The borehole instrument has been proved under laboratory and field conditions at 10-40 deg C

  15. MONSTER: a TOF Spectrometer for beta-delayed Neutron Spetroscopy

    CERN Document Server

    Martinez, T; Castilla, J; Garcia, A R; Marin, J; Martinez, G; Mendoza, E; Santos, C; Tera, F; Jordan, M D; Rubio, B; Tain, J L; Bhattacharya, C; Banerjee, K; Bhattacharya, S; Roy, P; Meena, J K; Kundu, S; Mukherjee, G; Ghosh, T K; Rana, T K; Pandey, R; Saxena, A; Behera, B; Penttila, H; Jokinen, A; Rinta-Antila, S; Guerrero, C; Ovejero, M C; Villamarin, D; Agramunt, J; Algora, A

    2014-01-01

    Beta-delayed neutron (DN) data, including emission probabilities, P-n, and energy spectrum, play an important role in our understanding of nuclear structure, nuclear astrophysics and nuclear technologies. A MOdular Neutron time-of-flight SpectromeTER (MONSTER) is being built for the measurement of the neutron energy spectra and branching ratios. The TOF spectrometer will consist of one hundred liquid scintillator cells covering a significant solid angle. The MONSTER design has been optimized by using Monte Carlo (MC) techniques. The response function of the MONSTER cell has been characterized with mono-energetic neutron beams and compared to dedicated MC simulations.

  16. Microprocessor-controlled portable neutron spectrometer

    International Nuclear Information System (INIS)

    Hunt, G.F.; Kaifer, R.C.; Slaughter, D.R.; Strout, R.E. II; Rueppel, D.W.

    1979-01-01

    A neutron spectrometer that acquires and unfolds data in the field has been developed for use in the energy range from 1 to 20 MeV. The system includes an NE213 organic scintillation detector, automatic gain stabilization, automatically stabilized pulseshape discrimination, an LSl-11 microprocessor for control and data reduction, and a multichannel analyzer for data acquisition. The system, with the exception of the multichannel analyzer, is mounted in a suitcase 47 by 66 by 23.5 cm. The mass is 23.5 kg

  17. Fast neutron spectrometer with pulse shape discrimination

    International Nuclear Information System (INIS)

    Verbitsky, S.S.

    1978-01-01

    A fast neutron spectrometer with a stilbene single crystal designed to operate at high pulsed count rate has been described. Making use of identification and rejection of events, accompanied by pile-up, allowed to increase permissible count rates by an order of magnitude. The results of energy dependence of signal amplitude and shape relative anisotropy in stilbene in the range 4-10 and 2-8 MeV respectively have been presented. Taking into account anisotropy of the detector-scintillation properties allowed to improve particle discrimination. (Auth.)

  18. Glass scintillator pair for compensation neutron logging

    International Nuclear Information System (INIS)

    Ji Changsong; Li Xuezhi; Yiu Guangduo

    1985-01-01

    Glass scintillator pair types ST 1604 and ST 1605 for compensation of neutron logging is developed. The neutron sensitive material used is multistick lithium glass scintillators 3 and 4 mm in diameter respectively. Thermoneutron detection efficiencies are 50-60% and 100% respectively. The detection efficiency for 60 Co γ ray is lower than 0.3%. The type ST 1604 and ST 1605 may also be used as high sensitive neutron detectors in an intensive γ ray field

  19. Spectrometers for compact neutron sources

    Science.gov (United States)

    Voigt, J.; Böhm, S.; Dabruck, J. P.; Rücker, U.; Gutberlet, T.; Brückel, T.

    2018-03-01

    We discuss the potential for neutron spectrometers at novel accelerator driven compact neutron sources. Such a High Brilliance Source (HBS) relies on low energy nuclear reactions, which enable cryogenic moderators in very close proximity to the target and neutron optics at comparably short distances from the moderator compared to existing sources. While the first effect aims at increasing the phase space density of a moderator, the second allows the extraction of a large phase space volume, which is typically requested for spectrometer applications. We find that competitive spectrometers can be realized if (a) the neutron production rate can be synchronized with the experiment repetition rate and (b) the emission characteristics of the moderator can be matched to the phase space requirements of the experiment. MCNP simulations for protons or deuterons on a Beryllium target with a suitable target/moderator design yield a source brightness, from which we calculate the sample fluxes by phase space considerations for different types of spectrometers. These match closely the figures of todays spectrometers at medium flux sources. Hence we conclude that compact neutron sources might be a viable option for next generation neutron sources.

  20. Liquid scintillation spectrometer survey 155Eu liquid activity

    International Nuclear Information System (INIS)

    Zhang Zuhua

    2002-01-01

    In the countrywide contrasting survey of 155 Eu activity, 155 Eu liquid activity was determined for the first time through using liquid scintillation spectrometer survey 155 Eu β ray. In survey total uncertainty, determining activity accord with determining activity average value of all a wide variety of survey instrument entering into contrasting survey. But using liquid scintillation spectrometer survey, it is simple and save time, is beyond compare for other survey method. It indicate liquid scintillation spectrometer survey β-γ nuclide activity is effective as well

  1. A gamma-ray discriminating neutron scintillator

    International Nuclear Information System (INIS)

    Eschbach, P.A.; Miller, S.D.; Cole, M.C.

    1994-01-01

    A neutron scintillator has been developed at Pacific Northwest Laboratory which responds directly to as little as 10 mrem/hour dose equivalent rate fast neutron fields. The scintillator is composed of CaF 2 :Eu or of NaI grains within a silicone rubber or polystyrene matrix, respectively. Neutrons colliding with the plastic matrix provide knockon protons, which in turn deposit energy within the grains of phosphor to produce pulses of light. Neutron interactions are discriminated from gamma-ray events on the basis of pulse height. Unlike NE-213 liquid scintillators, this solid scintillator requires no pulseshape discrimination and therefore requires less hardware. Neutron events are anywhere from two to three times larger than the gamma-ray exposures are compared to 0.7 MeV gamma-ray exposures. The CaF 2 :Eu/silicone rubber scintillator is nearly optically transparent, and can be made into a very sizable detector (4 cm x 1.5 cm) without degrading pulse height. This CaF 2 :Eu scintillator has been observed to have an absolute efficiency of 0.1% when exposed to 5-MeV accelerator-generated neutrons (where the absolute efficiency is the ratio of observed neutron events divided by the number of fast neutrons striking the detector)

  2. Development of cold neutron spectrometers

    International Nuclear Information System (INIS)

    Lee, Changhee; Lee, C. H.; So, J. Y.; Park, S.; Han, Y. S.; Cho, S. J.; Moon, M. K.; Choi, Y. H.; Sun, G. M.

    2012-03-01

    □ Cold Neutron Triple Axsis Spectrometer (Cold-TAS) Development Ο Fabrication and Installation of the Major Cold-TAS Components Ο Performance Test of the Cold-TAS □ Cold Neutron Time-of-Flight Spectrometer(DC-TOF) Development Ο Fabrication of the Major DC-TOF Components Ο Development DC-TOF Data Reduction Software □ Expected Contribution The two world-class inelastic neutron scattering instruments measure atomic or molecular scale dynamics of meV energy range. This unprecedented measurement capability in the country will enable domestic and international scientists to observe new phenomena in their materials research to obtain world class results. Especially those who work in the fields of magnetic properties of superconductors and multiferroics, molecular dynamics, etc. will get more benefit from these two instruments

  3. Neutron energy response measurement of scintillation detectors

    International Nuclear Information System (INIS)

    Yang Hongqiong; Peng Taiping; Yang Jianlun; Tang Zhengyuan; Yang Gaozhao; Li Linbo; Hu Mengchun; Wang Zhentong; Zhang Jianhua; Li Zhongbao; Wang Lizong

    2004-01-01

    Neutron sensitivities of detectors composed of plastic scintillator ST401, ST1422, ST1423 and phyotomultiplier tube in primary energy range of fission neutron are calibrated by direct current. The energy response curve of the detectors is obtained in this experiment. The experimental result has been compared with the theoretical calculation and they are in agreement within measuring uncertainty. (authors)

  4. Scintillation forward spectrometer of the SPHERE setup

    International Nuclear Information System (INIS)

    Anisimov, Yu.S.; Afanas'ev, S.V.; Bondarev, V.K.

    1991-01-01

    The construction of the forward spectrometer for the 4π SPHERE setup to study multiple production of particles in nucleus-nucleus interactions is described. The measured parameters of the spectrometer detectors are presented. 7 refs.; 14 figs.; 1 tab

  5. Plastic fiber scintillator response to fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Danly, C. R.; Sjue, S.; Wilde, C. H.; Merrill, F. E.; Haight, R. C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-11-15

    The Neutron Imaging System at NIF uses an array of plastic scintillator fibers in conjunction with a time-gated imaging system to form an image of the neutron emission from the imploded capsule. By gating on neutrons that have scattered from the 14.1 MeV DT energy to lower energy ranges, an image of the dense, cold fuel around the hotspot is also obtained. An unmoderated spallation neutron beamline at the Weapons Neutron Research facility at Los Alamos was used in conjunction with a time-gated imaging system to measure the yield of a scintillating fiber array over several energy bands ranging from 1 to 15 MeV. The results and comparison to simulation are presented.

  6. A solenoidal electron spectrometer for a precision measurement of the neutron β-asymmetry with ultracold neutrons

    International Nuclear Information System (INIS)

    Plaster, B.; Carr, R.; Filippone, B.W.; Harrison, D.; Hsiao, J.; Ito, T.M.; Liu, J.; Martin, J.W.; Tipton, B.; Yuan, J.

    2008-01-01

    We describe an electron spectrometer designed for a precision measurement of the neutron β-asymmetry with spin-polarized ultracold neutrons. The spectrometer consists of a 1.0-T solenoidal field with two identical multiwire proportional chamber and plastic scintillator electron detector packages situated within 0.6-T field-expansion regions. Select results from performance studies of the spectrometer with calibration sources are reported

  7. A solenoidal electron spectrometer for a precision measurement of the neutron {beta}-asymmetry with ultracold neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Plaster, B. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States)], E-mail: plaster@pa.uky.edu; Carr, R.; Filippone, B.W. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Harrison, D. [Physics Department, University of Winnipeg, Manitoba, Canada R3B 2E9 (Canada); Hsiao, J. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Ito, T.M. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Liu, J. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Martin, J.W. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Physics Department, University of Winnipeg, Manitoba, R3B 2E9 (Canada); Tipton, B.; Yuan, J. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States)

    2008-10-11

    We describe an electron spectrometer designed for a precision measurement of the neutron {beta}-asymmetry with spin-polarized ultracold neutrons. The spectrometer consists of a 1.0-T solenoidal field with two identical multiwire proportional chamber and plastic scintillator electron detector packages situated within 0.6-T field-expansion regions. Select results from performance studies of the spectrometer with calibration sources are reported.

  8. Neutron measurement by transportable spectrometer

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    Two levels of neutron spectrometry are in regular use at nuclear power plants: some techniques used in the laboratory produce detailed spectra but require specialist operators, while simple instruments used by non-specialists to measure the neutron dose-rate to operators provide little spectral information. The standard portable instruments are therefore of no use when anomalous readings are obtained which require further investigation. AEA Technology at Winfrith has developed a Transportable Neutron Spectrometer (TNS) which is designed to produce reasonable spectra in routine use by staff with no specialist skill in spectroscopy, and high-quality spectra in the hands of skilled staff. The TNS provides a level of information intermediate between those currently available, and is also designed to solve the problem of imperfect dose response which is common in portable dosimeters. The TNS system consists of a power supply, a probe and a signal processing and data acquisition unit. (author)

  9. Polarized epithermal neutron spectrometer at KENS

    International Nuclear Information System (INIS)

    Kohgi, M.

    1983-01-01

    A spectrometer employing a white, epithermal, polarized neutron beam is under construction at KENS. The neutron polarization is achieved by passage through a dynamically polarized proton filter (DPPF). The results of the test experiments show that the DPPF method is promising in obtaining polarized epithermal neutron beam. The basic design of the spectrometer is described

  10. A neutron spectrometer for studying giant resonances with (p,n) reactions in inverse kinematics

    International Nuclear Information System (INIS)

    Stuhl, L.; Krasznahorkay, A.; Csatlós, M.; Algora, A.; Gulyás, J.; Kalinka, G.; Timár, J.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M.A.

    2014-01-01

    A neutron spectrometer, the European Low-Energy Neutron Spectrometer (ELENS), has been constructed to study exotic nuclei in inverse-kinematics experiments. The spectrometer, which consists of plastic scintillator bars, can be operated in the neutron energy range of 100 keV–10 MeV. The neutron energy is determined using the time-of-flight technique, while the position of the neutron detection is deduced from the time-difference information from photomultipliers attached to both ends of each bar. A novel wrapping method has been developed for the plastic scintillators. The array has a larger than 25% detection efficiency for neutrons of approximately 500 keV in kinetic energy and an angular resolution of less than 1°. Details of the design, construction and experimental tests of the spectrometer will be presented

  11. YAP scintillators for resonant detection of epithermal neutrons at pulsed neutron sources

    International Nuclear Information System (INIS)

    Tardocchi, M.; Gorini, G.; Pietropaolo, A.; Andreani, C.; Senesi, R.; Rhodes, N.; Schooneveld, E. M.

    2004-01-01

    Recent studies indicate the resonance detector (RD) technique as an interesting approach for neutron spectroscopy in the electron volt energy region. This work summarizes the results of a series of experiments where RD consisting of YAlO 3 (YAP) scintillators were used to detect scattered neutrons with energy in the range 1-200 eV. The response of YAP scintillators to radiative capture γ emission from a 238 U analyzer foil was characterized in a series of experiments performed on the VESUVIO spectrometer at the ISIS pulsed neutron source. In these experiments a biparametric data acquisition allowed the simultaneous measurements of both neutron time-of-flight and γ pulse height (energy) spectra. The analysis of the γ pulse height and neutron time of flight spectra permitted to identify and distinguish the signal and background components. These measurements showed that a significant improvement in the signal-to-background ratio can be achieved by setting a lower level discrimination on the pulse height at about 600 keV equivalent photon energy. Present results strongly indicate YAP scintillators as the ideal candidate for neutron scattering studies with epithermal neutrons at both very low (<5 deg.) and intermediate scattering angles

  12. LANSA: A large neutron scintillator array for neutron spectroscopy at Nova

    International Nuclear Information System (INIS)

    Nelson, M.B.; Cable, M.D.; Bennett, C.K.; Mant, G.

    1992-01-01

    A very sensitive neutron time-of-flight spectrometer is now in use at Nova. LANSA consists of 960 channels of a neutron sensitive liquid scintillator (10 x lO x lO cm) coupled to a photomultiplier tube followed by a discriminator, TDC and ADC to allow the measurement of neutron arrival time as well as pulse size. LANSA is capable of measuring yields as low as 2.3 x 10 5 DT neutrons (100 detected hits) with resolution of 2.3 ns (170 key for 14 MeV neutrons with 20 m flight path). Shielding and collimation provide background levels low enough to allow measurement of secondary and tertiary reaction neutrons. Details of design, testing, calibration and experimental results will be presented. This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48

  13. COOLC, Ne-213 Liquid Scintillation Detector Neutron Spectra Unfolding

    International Nuclear Information System (INIS)

    1971-01-01

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

  14. Marine radioactivity measurements with liquid scintillation spectrometers

    International Nuclear Information System (INIS)

    Liong Wee Kwong, L.; Povinec, P.P.

    1999-01-01

    Liquid Scintillation Spectrometry (LSS) has now become the most widespread method for quantitative analytical measurement of low levels of β-emitting radionuclides like 3 H and 14 C. The high efficiency resulting from the latest development in LSS makes this technique not only appropriate but also enables direct measurement in environmental samples without excessive preparation. The introduction of several new cocktails based on solvents with a high flashpoint containing surfactants and having a high degree of aqueous sample compatibility has also contributed to the simplification of procedures

  15. Neutron-gamma discrimination of boron loaded plastic scintillator

    International Nuclear Information System (INIS)

    Wang Dong; He Bin; Zhang Quanhu; Wu Chuangxin; Luo Zhonghui

    2010-01-01

    Boron loaded plastic scintillator could detect both fast neutrons thanks to hydrogen and thermal neutrons thanks to 10B. Both reactions have large cross sections, and results in high detection efficiency of incident neutrons. However, similar with other organic scintillators, boron loaded plastic scintillator is sensitive to gamma rays and neutrons. So gamma rays must be rejected from neutrons using their different behavior in the scintillator. In the present research zero crossing method was used to test neutron-gamma discrimination of BC454 boron loaded plastic scintillator. There are three Gaussian peaks in the time spectrum, they are corresponding to gamma rays, fast neutrons and flow neutrons respectively. Conclusion could be made that BC454 could clear discriminate slow neutrons and gamma, but the discrimination performance turns poor as the neutrons' energy becomes larger. (authors)

  16. High intensity TOF spectrometer for cold neutrons

    International Nuclear Information System (INIS)

    Maayouf, R.M.; Abd El-Kawy, A.; Habib, N.; Adib, M.; Hamouda, I.

    1984-01-01

    This work presents a neutron time-of-flight (TOF) spectrometer developed specially for total neutron cross-section measurements at neutron energies below 5 MeV and sample's temperature varying from the liquid nitrogen one and up to 500 0 K. The spectrometer is equipped by remote control unit, designed especially, in order to move the sample in and out of the beam during the experimental measurements. The spectrometer has proved to be useful for transmission measurements at neutron energies below 5 MeV. It has a reasonable energy resolution (4.4%) and high effect to background ratio (11.1) at 5 MeV

  17. Neutron spectrometry with organic scintillation detector

    International Nuclear Information System (INIS)

    Butragueno Casado, J. L.

    1972-01-01

    This work describes a fast neutron spectrometer using a stilbene crystal as head detector with pulse shape discrimination (P.S.D.) to reject gamma background. Tre experimental procedure involves the P.S.D., the measurements to calibrate the spectrometer and the corrections for several factors, mainly the non-linear response of the stilbene. Results of the measurements with the reaction D 2 (d,n)He 3 , and with an Am-Be neutron source are presented. It is also presented the measurement of the spectrum of the fast reactor CCRAl-1. (Author) 17 refs

  18. 1987 calibration of the TFTR neutron spectrometers

    International Nuclear Information System (INIS)

    Barnes, C.W.; Strachan, J.D.; Princeton Univ., NJ

    1989-12-01

    The 3 He neutron spectrometer used for measuring ion temperatures and the NE213 proton recoil spectrometer used for triton burnup measurements were absolutely calibrated with DT and DD neutron generators placed inside the TFTR vacuum vessel. The details of the detector response and calibration are presented. Comparisons are made to the neutron source strengths measured from other calibrated systems. 23 refs., 19 figs., 6 tabs

  19. Scintillation neutron detector with dynamic threshold

    International Nuclear Information System (INIS)

    Kornilov, N.; Massey, T.; Grimes, S.

    2014-01-01

    Scintillation neutron detectors with hydrogen are a common tool for neutron spectroscopy. They provide good time resolution, neutron-gamma discrimination and high efficiency of neutron counting. The real open problems connected with application of these detectors are in the energy range >10 MeV. There are no standard neutron spectra known with high accuracy for this energy range. Therefore, traditional methods for experimental investigation of the efficiency function fail for these neutrons. The Monte Carlo simulation cannot provide reasonable accuracy due to unknown characteristics of the reactions for charged particle production (p, α and so on, light output, reaction cross-sections). The application of fission chamber with fissile material as a neutron detector did not help to solve the problem. We may avoid many problems if we use the traditional neutron detector with non-traditional data analysis. In this report we give main relations, and demonstrate the method for Cf-source. Experimental detector efficiency is compared with MC simulation. (authors)

  20. Study of neutron spectrometers for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Kaellne, Jan

    2005-11-15

    A review is presented of the developments in the field of neutron emission spectrometry (NES) which is of relevance for identifying the role of NES diagnostics on ITER and selecting suitable instrumentation. Neutron spectrometers will be part of the ITER neutron diagnostic complement and this study makes a special effort to examine which performance characteristics the spectrometers should possess to provide the best burning plasma diagnostic information together with neutron cameras and neutron yield monitors. The performance of NES diagnostics is coupled to how much interface space can be provided which has lead to an interest to find compact instruments and their NES capabilities. This study assesses all known spectrometer types of potential interest for ITER and makes a ranking of their performance (as demonstrated or projected), which, in turn, are compared with ITER measurement requirements as a reference; the ratio of diagnostic performance to interface cost for different spectrometers is also discussed for different spectrometer types. The overall result of the study is an assessment of which diagnostic functions neutron measurements can provide in burning plasma fusion experiments on ITER and the role that NES can play depending on the category of instrument installed. Of special note is the result that much higher quality diagnostic information can be obtained from neutron measurements with total yield monitors, profile flux cameras and spectrometers when the synergy in the data is considered in the analysis and interpretation.

  1. Calibration of the neutron scintillation counter threshold

    International Nuclear Information System (INIS)

    Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.

    1978-01-01

    A method for calibrating the threshold of a neutron counter in the form of a 10x10x40 cm plastic scintillator is described. The method is based on the evaluation of the Compton boundary of γ-spectrum from the discrimination curve of counter loading. The results of calibration using 60 Co and 24 Na γ-sources are given. In order to eValuate the Compton edge rapidly, linear extrapolation of the linear part of the discrimination curve towards its intersection with the X axis is recommended. Special measurements have shown that the calibration results do not practically depend on the distance between the cathode of a photomultiplier and the place where collimated γ-radiation of the calibration source reaches the scintillator

  2. Improved Neutron Scintillators Based on Nanomaterials

    International Nuclear Information System (INIS)

    Friesel, Dennis

    2008-01-01

    The development work conducted in this SBIR has so far not supported the premise that using nano-particles in LiFZnS:Ag foils improves their transparency to 420 (or other frequency) light. This conclusion is based solely on the light absorption properties of LiFZnS foils fabricated from nano- and from micro-particles. Furthermore, even for the case of the Gd 2 O 3 foils, the transmission of 420 nm light gained by using nano-particles all but disappears as the foil thickness is increased beyond about 0.2 mm, a practical scintillator thickness. This was not immediately apparent from the preliminary study since no foils thicker than about 0.04 mm were produced. Initially it was believed that the failure to see an improvement by using nano-particles for the LiFZnS foils was caused by the clumping of the particles in Toluene due to the polarity of the ZnS particles. However, we found, much to our surprise, that nano-particle ZnS alone in polystyrene, and in Epoxy, had worse light transmission properties than the micro-particle foils for equivalent thickness and density foils. The neutron detection measurements, while disappointing, are attributable to our inability to procure or fabricate Bulk Doped ZnS nanoparticles. The cause for the failure of nano-particles to improve the scintillation light, and hence improved neutron detection efficiency, is a fundamental one of light scattering within the scintillator. A consequence of PartTec's documentation of this is that several concepts for the fabrication of improved 6 LiFZnS scintillators were formulated that will be the subject of a future SBIR submission.

  3. Light collection and its fluctuation in Cherenkov and scintillation spectrometers

    International Nuclear Information System (INIS)

    Kitaev, D.F.; Samedov, V.V.; Stolyarova, E.L.

    1982-01-01

    The GAMMA program for calculating light collection in the Cherenkov and scintillation counters is described. Together with the shower modelling program the GAMNA program can be used for evaluating the output signal and energy resolution of shower spectrometers. Principle formulae and block diagram of the program are given. Results of test calculations performed on the example of scintillation counters of culindrical and rectangular shapes were considered. Modelling of the radiation polarization envisaged in the program permits to take account of the effect of selective discrimination of photoelectron amplifier photocathode. The program analyzes, for the present situation, calculation errors which permits to plan in advance the calculation with the given accuracy. The program permits to use additional subprograms together with it where it is possible to take account of other peculiarities of light collection, for example, the presence of outer reflectors and focusing elements of light collection systems, particle slowing down in the spectrometer radiator expressed in the change of angle of semiaperture of the Cherenkov radiation cone. It is concluded on the basis of analyzing results of test calculations that the choosen technique and algorithms of light collection coefficient calculation in spectrometer radiators are correct

  4. Field neutron spectrometer using 3He, TEPC, and multisphere detectors

    International Nuclear Information System (INIS)

    Brackenbush, L.W.

    1991-01-01

    Since the last DOE Neutron Dosimetry Workshop, there have been a number of changes in radiation protection standards proposed by national and international advisory bodies. These changes include: increasing quality factors for neutrons by a factor of two, defining quality factors as a function of lineal energy rather than linear energy transfer (see ACCRUE-40; Joint Task Group 1986), and adoption of effective dose equivalent methodologies. In order to determine the effects of these proposed changes, it is necessary to know the neutron energy spectrum in the work place. In response to the possible adoption of these proposals, the Department of Energy (DOE) initiated a program to develop practical neutron spectrometry systems for use by health physicists. One part of this program was the development of a truly portable, battery operated liquid scintillator spectrometer using proprietary electronics developed at Lawrence Livermore National Laboratory (LLNL); this instrument will be described in the following paper. The second part was the development at PNL of a simple transportable spectrometer based on commercially available electronics. This open-quotes field neutron spectrometerclose quotes described in this paper is intended to be used over a range of neutron energies extending from thermal to 20 MeV

  5. A spectrometer filter for semiconductor and scintillation detectors

    International Nuclear Information System (INIS)

    Andronov, O.I.; Brovchenko, V.G.; Evdokimov, S.T.

    1995-01-01

    The paper describes an integrating low-pass filter which takes signals from a delay line. The filter changes triangular pulses into rectangular ones. The energy resolution of a semiconductor detector whose signal is processed by the filter is 15-20% better than using a common RC-filter. The integrator stores a charge due to the scintillation pulse during the integration time without loss. The energy and time resolution of the device with the spectrometer filter is better than with an RC-filter. The energy resolution of a bismuth-germanate detector in recording radiation from 137 Cs is 9.75%

  6. A proposed neutron spectrometer system for JET

    International Nuclear Information System (INIS)

    Elevant, T.; Hellbom, G.; Scheffel, J.; Malmskog, S.

    1979-12-01

    A neutron spectrometer system is proposed primarily for measurements of ion temperature and density and ion beam energy distribution in extended fusion plasmas like e.g. in JET. Three different spectrometers are involved: time of flight, proton recoil and 3 He. Energy resolutions of a few percent both for DD and DT neutrons are provided. Six order of magnitudes in flux ranges will be covered by the system when employing multi-target systems. A neutron collimator and shielding system will be desirable in order to obtain relevant information. Due to the entire differences in energy and fluxes for DD and DT plasmas a flexible collimator-shielding system is recommended

  7. The development of a spectrometer for 14 MeV neutrons from fusion

    International Nuclear Information System (INIS)

    Aronsson, D.

    1991-01-01

    A spectrometer for 14 MeV neutrons, to be used for fusion plasma diagnostics at JET, was developed. The spectrometer utilizes neutron scattering in a polyethylene foil with the detection of the scattered neutron and its associated recoil proton. For the detection of 12 MeV protons we have tested silicon surface barrier detectors, lithium-drifted silicon detectors and high purity germanium detectors. The lithium-drifted detectors were finally selected for use in the spectrometer. The lithium-drifted silicon diodes have also been used for direct spectrometry, utilizing the neutron induced charged particle reactions in silicon. The methods used for the energy calibration and the timing calibration of the diodes, both during the installation of the spectrometer and during operation, are described. The detection of 2 MeV neutrons is done by fast plastic scintillators. Since the neutron generator which was used to test the detectors supplies 14 MeV or 2.5 MeV neutrons only, a neutron energy converter has to be constructed to study the detectors at other neutron energies. In the actual spectrometer an array of scintillation neutron detectors is used. A method of calibrating such an array of detectors with a gamma source was elaborated and is also described here. The result of the calibration is a set of parameters than can be used to determine the high voltage settings and the discriminator levels that are needed to achieve homogeneous sensitivity for all the detectors of the array. The energy scale itself was then calibrated by using gamma sources of various energies. To test the spectrometer as a whole at a neutron generator, a test bed was constructed. A lithium-drifted silicon diode was used to measure the neutron flux and the neutron energy resolution in the test bed. (au)

  8. Scintillator Based Coded-Aperture Imaging for Neutron Detection

    International Nuclear Information System (INIS)

    Hayes, Sean-C.; Gamage, Kelum-A-A.

    2013-06-01

    In this paper we are going to assess the variations of neutron images using a series of Monte Carlo simulations. We are going to study neutron images of the same neutron source with different source locations, using a scintillator based coded-aperture system. The Monte Carlo simulations have been conducted making use of the EJ-426 neutron scintillator detector. This type of detector has a low sensitivity to gamma rays and is therefore of particular use in a system with a source that emits a mixed radiation field. From the use of different source locations, several neutron images have been produced, compared both qualitatively and quantitatively for each case. This allows conclusions to be drawn on how suited the scintillator based coded-aperture neutron imaging system is to detecting various neutron source locations. This type of neutron imaging system can be easily used to identify and locate nuclear materials precisely. (authors)

  9. Proposed 14-MeV neutron spectrometer system for jet

    International Nuclear Information System (INIS)

    Elevant, T.

    1983-09-01

    In order to cover a broad range of neutron spectra and fluxes during D-T operation in JET we propose the use of two different detector techniques neutron induced reactions in a silicon surface barrier detector and neutron-proton elastic scattering in a liquid scintillator. Experimental investigations of 28 Si(n,α) 25 Mg reactions have resulted in resolutions of ΔE(FWHM)/E=0.02 with intrinsic efficiency equal to 10 -4 and a maximum useful countrate equal to 1600 c.p.s. However, due to overlap of adjacent peaks, caused by excited states of 25 Mg, this spectrometer has an operation range limited to FWHM/E=0.04. For broader neutron distributions we propose the use of a conventional liquid scintillator system with a light guide, photomultiplier tube and modified conventional electronics. Experiments have demonstrated a resolution equal to 0.05 and a n/γ separation better than 90percent at total countrates equal to 2times10 5 c.p.s. (author)

  10. Miniature neutron-alpha activation spectrometer

    International Nuclear Information System (INIS)

    Rhodes, Edgar; Goldsten, John; Holloway, James Paul; He, Zhong

    2002-01-01

    We are developing a miniature neutron-alpha activation spectrometer for in-situ analysis of chem-bio samples, including rocks, fines, ices, and drill cores, suitable for a lander or Rover platform for Mars or outer-planet missions. In the neutron-activation mode, penetrating analysis will be performed of the whole sample using a γ spectrometer and in the α-activation mode, the sample surface will be analyzed using Rutherford-backscatter and x-ray spectrometers. Novel in our approach is the development of a switchable radioactive neutron source and a small high-resolution γ detector. The detectors and electronics will benefit from remote unattended operation capabilities resulting from our NEAR XGRS heritage and recent development of a Ge γ detector for MESSENGER. Much of the technology used in this instrument can be adapted to portable or unattended terrestrial applications for detection of explosives, chemical toxins, nuclear weapons, and contraband

  11. A neutron time of flight spectrometer appropriate for D-T plasma diagnostics

    International Nuclear Information System (INIS)

    Elevant, T.

    1984-02-01

    A neutron time-of-flight spectrometer with 2 m flight path for diagnostics of deuterium plasmas in JET is presently under construction. An upgrade of this spectrometer to make it appropriate for 14-MeV neutron spectroscopy is presented here. It is suggested to use backscattering in a deuterium based scintillator. The flight path length is 1-2 m and the efficiency is of the order of 2.10 -5 cm -5 . Results from test of principle are presented with estimates for neutron and gamma backgrounds

  12. Some characteristics of a miniature neutron spectrometer

    International Nuclear Information System (INIS)

    Sekimoto, H.; Oishi, K.; Hojo, K.; Hojo, T.

    1984-01-01

    Some characteristics of an NE213 miniature spherical spectrometer for in-assembly fast-neutron spectrometry were measured. As the bubbling time changed, the pulse-height did not change appreciably, but the n-γ discrimination characteristics changed considerably. As the count rate changed, the pulse-height did not change appreciably, and the change of the n-γ discrimination characteristics was acceptable. The neutron response function was measured to be almost isotropic except for the backward direction. (orig.)

  13. J-NSE: Neutron spin echo spectrometer

    Directory of Open Access Journals (Sweden)

    Olaf Holderer

    2015-08-01

    Full Text Available Neutron Spin-Echo (NSE spectroscopy is well known as the only neutron scattering technique that achieves energy resolution of several neV. By using the spin precession of polarized neutrons in magnetic field one can measure tiny velocity changes of the individual neutron during the scattering process. Contrary to other inelastic neutron scattering techniques, NSE measures the intermediate scattering function S(Q,t in reciprocal space and time directly. The Neutron Spin-Echo spectrometer J-NSE, operated by JCNS, Forschungszentrum Jülich at the Heinz Maier-Leibnitz Zentrum (MLZ in Garching, covers a time range (2 ps to 200 ns on length scales accessible by small angle scattering technique. Along with conventional NSE spectroscopy that allows bulk measurements in transmission mode, J-NSE offers a new possibility - gracing incidence spin echo spectroscopy (GINSENS, developed to be used as "push-button" option in order to resolve the depth dependent near surface dynamics.

  14. Development and Characterization of a High Sensitivity Segmented Fast Neutron Spectrometer (FaNS-2).

    Science.gov (United States)

    Langford, T J; Beise, E J; Breuer, H; Heimbach, C R; Ji, G; Nico, J S

    2016-01-01

    We present the development of a segmented fast neutron spectrometer (FaNS-2) based upon plastic scintillator and 3 He proportional counters. It was designed to measure both the flux and spectrum of fast neutrons in the energy range of few MeV to 1 GeV. FaNS-2 utilizes capture-gated spectroscopy to identify neutron events and reject backgrounds. Neutrons deposit energy in the plastic scintillator before capturing on a 3 He nucleus in the proportional counters. Segmentation improves neutron energy reconstruction while the large volume of scintillator increases sensitivity to low neutron fluxes. A main goal of its design is to study comparatively low neutron fluxes, such as cosmogenic neutrons at the Earth's surface, in an underground environment, or from low-activity neutron sources. In this paper, we present details of its design and construction as well as its characterization with a calibrated 252 Cf source and monoenergetic neutron fields of 2.5 MeV and 14 MeV. Detected monoenergetic neutron spectra are unfolded using a Singular Value Decomposition method, demonstrating a 5% energy resolution at 14 MeV. Finally, we discuss plans for measuring the surface and underground cosmogenic neutron spectra with FaNS-2.

  15. Construction and performance-testing of a scintillation spectrometer

    International Nuclear Information System (INIS)

    Berthier, J.; Locard, P.; Hocquenghem, J.C.; Goin, G.

    1966-01-01

    We first describe the realisation of a scintillation spectrometer based on the 'Fast-slow' coincidences technique. The counters use 56 A.V.P. fast photomultipliers. The fast coincidences unit can also be used as time-to- height pulses converter. The resolving time, with two NaI crystals, is about 14 nanoseconds. We show, at the end, the measurements which can be undertaken with our apparatus: β-γ or γ-γ coincidences, 'Sum-spectra', life time measurements, β-γ or γ-γ directional angular correlation measurements (with detection or not of the linear polarization) and we give, for each case, the results of test-measurements. (authors) [fr

  16. Martian Neutron Energy Spectrometer (MANES)

    Science.gov (United States)

    Maurer, R. H.; Roth, D. R.; Kinnison, J. D.; Goldsten, J. O.; Fainchtein, R.; Badhwar, G.

    2000-01-01

    High energy charged particles of extragalactic, galactic, and solar origin collide with spacecraft structures and planetary atmospheres. These primaries create a number of secondary particles inside the structures or on the surfaces of planets to produce a significant radiation environment. This radiation is a threat to long term inhabitants and travelers for interplanetary missions and produces an increased risk of carcinogenesis, central nervous system (CNS) and DNA damage. Charged particles are readily detected; but, neutrons, being electrically neutral, are much more difficult to monitor. These secondary neutrons are reported to contribute 30-60% of the dose equivalent in the Shuttle and MIR station. The Martian atmosphere has an areal density of 37 g/sq cm primarily of carbon dioxide molecules. This shallow atmosphere presents fewer mean free paths to the bombarding cosmic rays and solar particles. The secondary neutrons present at the surface of Mars will have undergone fewer generations of collisions and have higher energies than at sea level on Earth. Albedo neutrons produced by collisions with the Martian surface material will also contribute to the radiation environment. The increased threat of radiation damage to humans on Mars occurs when neutrons of higher mean energy traverse the thin, dry Martian atmosphere and encounter water in the astronaut's body. Water, being hydrogeneous, efficiently moderates the high energy neutrons thereby slowing them as they penetrate deeply into the body. Consequently, greater radiation doses can be deposited in or near critical organs such as the liver or spleen than is the case on Earth. A second significant threat is the possibility of a high energy heavy ion or neutron causing a DNA double strand break in a single strike.

  17. A Time of flight spectrometer for measurements of double differential neutron scattering cross sections

    International Nuclear Information System (INIS)

    Padron, I.; Dominguez, O.; Sarria, P. Sandin, C.

    1996-01-01

    The time -of-Flight neutron spectrometry technique by associated particle method was improved using a D-T neutron generator at Laboratory of Nuclear Analysis. This technique was implemented for double differential cross section measurements and supported by the IAEA Project CUB/01/005. An stilbene scintillation detector (dia=100 mm, length=50 mm) was used as principal neutron detector detector and was situated outside a hole in the concrete wall. This way the fligth path was extended and the scattered neutron cone accurate collimated throught the 2 m concrete wall. For the associated particle α detection a thin plastic NE-102 scint illator was used, as well as, two scintilation detectors and a long counter for the neutron flux monitoring. In this TOF neutron spectrometer (3.40 m flight path) a 1.7 nseg. temporal resolution was obtained

  18. Upgrade of neutron energy spectrometer with single multilayer bonner sphere using onion-like structure

    International Nuclear Information System (INIS)

    Mizukpshi, Tomoaki; Watanabe, Kenichi; Yamazaki, Atsushi; Uritan, Akira; Iguchi, Tetsuo; Ogata, Tomohiro; Muramatsu, Takashi

    2016-01-01

    In order to measure neutron energy spectra, the conventional Bonner Sphere Spectrometers (BSS) are widely used. In this spectrometer, several measurements with different size Bonner spheres are required. Operators should, therefore, place these spheres in several times to a measurement point where radiation dose might be relatively high. In order to reduce this effort, novel neutron energy spectrometer using an onion-like single Bonner sphere was proposed in our group. This Bonner sphere has multiple sensitive spherical shell layers in the single sphere. In this spectrometer, a band-shaped thermal neutron detection medium, which consists of a LiF-ZnS mixed powder scintillator sheet and a wavelength-shifting (WLS) fiber readout, was looped to each sphere at equal angular intervals. Amount of LiF neutron converter is reduced near polar region, where the band-shaped detectors are concentrated, in order to uniform the directional sensitivity. The LiF-ZnS mixed powder has an advantage of extremely high light yield. However, since it is opaque, scintillation photons cannot be collect uniformly. This type of detector shows no characteristic shape in the pulse height spectrum. Subsequently, it is difficult to set the pulse height discrimination level. This issue causes sensitivity fluctuation due to gain instability of photodetectors and/or electric modules. In order to solve this problem, we propose to replace the LiF-ZnS mixed powder into a flexible and Transparent RUbber SheeT type LiCaAlF6 (TRUST LiCAF) scintillator. TRUST LiCAF scintillator can show a peak shape corresponding to neutron absorption events in the pulse height spectrum. We fabricated the prototype detector with five sensitive layers using TRUST LiCAF scintillator and conducted basic experiments to evaluate the directional uniformity of the sensitivity. The fabricated detector shows excellent directional uniformity of the neutron sensitivity

  19. Calibration of an electron volt neutron spectrometer

    International Nuclear Information System (INIS)

    Mayers, J.; Adams, M.A.

    2011-01-01

    The procedure for calibrating the VESUVIO eV neutron spectrometer at the ISIS neutron source is described. VESUVIO is used primarily to measure the momentum distribution n(p) of atoms, by inelastic scattering of very high energy (5-150 eV) neutrons. The results of the calibrations show that measurements of n(p) in atoms with masses lower than 16 amu can be measured with a resolution width ∼25% of the intrinsic peak widths in the current instrument configuration. Some suggestions as to how the instrument resolution could be significantly improved are made.

  20. Extension of the calibration of an NE-213 liquid scintillator based pulse height response spectrometer up to 18 MeV neutron energy and leakage spectrum measurements on bismuth at 8 MeV and 18 MeV neutron energies

    International Nuclear Information System (INIS)

    Fenyvesi, A.; Valastyan, I.; Olah, L.; Csikai, J.; Plompen, A.; Jaime, R.; Loevestam, G.; Semkova, V.

    2011-01-01

    Monoenergetic neutrons were produced at the Van de Graaff accelerator of the EC-JRC-Institute for Reference Materials and Measurements (IRMM, Geel, Belgium). An air-jet cooled D_2-gas target (1.2 bar, ΔE_d = 448 keV) was bombarded with E_d =4976 keV deuterons to produce neutrons up to E_n = 8 MeV energy via the D(d,n)"3He reaction. Higher energy neutrons up to E_n = 18 MeV were produced via the T(d,n)"4He reaction by bombarding a TiT target with E_d =1968 keV deuterons. Pulse height spectra were measured at different neutron energies from E_n = 8 MeV up to E_n = 18 MeV with the NE-213 liquid scintillator based Pulse Height Response Spectrometer (PHRS) of UD-IEP. The energy calibration of the PHRS system has been extended up to E_n = 18 MeV. Pulse height spectra induced by gamma photons have been simulated by the GRESP7 code. Neutron induced pulse height spectra have been simulated by the NRESP7 and MCNP-POLIMI codes. Comparison of the results of measurements and simulations enables the improvement of the parameter set of the function used by us to describe the light output dependence of the resolution of the PHRS system at light outputs of L > 2 light units. Also, it has been shown that the derivation method for unfolding neutron spectra from measured pulse height spectra performs well when relative measurements are done up to E_n = 18 MeV neutron energy. For matrix unfolding purposes, the NRESP7 code has to be preferred to calculate the pulse height response matrix of the PHRS system. Leakage spectra of neutrons behind bismuth slabs of different thicknesses have been measured with the PHRS system by using monoenergetic neutrons. The maximum slab thickness was d = 14 cm. Simulations of the measurements have been carried out with the MCNP-4c code. The necessary nuclear cross-sections were taken from the from the ENDF/B-VII and JEFF.3.1 data libraries. For both libraries, the agreement of measured and simulated neutron spectra is good for the 5 MeV ≤ En ≤ 18 Me

  1. Elpasolite Planetary Ice and Composition Spectrometer (EPICS): A Low-Resource Combined Gamma-Ray and Neutron Spectrometer for Planetary Science

    Science.gov (United States)

    Stonehill, L. C.; Coupland, D. D. S.; Dallmann, N. A.; Feldman, W. C.; Mesick, K.; Nowicki, S.; Storms, S.

    2017-12-01

    The Elpasolite Planetary Ice and Composition Spectrometer (EPICS) is an innovative, low-resource gamma-ray and neutron spectrometer for planetary science missions, enabled by new scintillator and photodetector technologies. Neutrons and gamma rays are produced by cosmic ray interactions with planetary bodies and their subsequent interactions with the near-surface materials produce distinctive energy spectra. Measuring these spectra reveals details of the planetary near-surface composition that are not accessible through any other phenomenology. EPICS will be the first planetary science instrument to fully integrate the neutron and gamma-ray spectrometers. This integration is enabled by the elpasolite family of scintillators that offer gamma-ray spectroscopy energy resolutions as good as 3% FWHM at 662 keV, thermal neutron sensitivity, and the ability to distinguish gamma-ray and neutron signals via pulse shape differences. This new detection technology will significantly reduce size, weight, and power (SWaP) while providing similar neutron performance and improved gamma energy resolution compared to previous scintillator instruments, and the ability to monitor the cosmic-ray source term. EPICS will detect scintillation light with silicon photomultipliers rather than traditional photomultiplier tubes, offering dramatic additional SWaP reduction. EPICS is under development with Los Alamos National Laboratory internal research and development funding. Here we report on the EPICS design, provide an update on the current status of the EPICS development, and discuss the expected sensitivity and performance of EPICS in several potential missions to airless bodies.

  2. Final LDRD report : advanced plastic scintillators for neutron detection.

    Energy Technology Data Exchange (ETDEWEB)

    Vance, Andrew L.; Mascarenhas, Nicholas; O' Bryan, Greg; Mrowka, Stanley

    2010-09-01

    This report summarizes the results of a one-year, feasibility-scale LDRD project that was conducted with the goal of developing new plastic scintillators capable of pulse shape discrimination (PSD) for neutron detection. Copolymers composed of matrix materials such as poly(methyl methacrylate) (PMMA) and blocks containing trans-stilbene (tSB) as the scintillator component were prepared and tested for gamma/neutron response. Block copolymer synthesis utilizing tSBMA proved unsuccessful so random copolymers containing up to 30% tSB were prepared. These copolymers were found to function as scintillators upon exposure to gamma radiation; however, they did not exhibit PSD when exposed to a neutron source. This project, while falling short of its ultimate goal, demonstrated the possible utility of single-component, undoped plastics as scintillators for applications that do not require PSD.

  3. Time dispersion in large plastic scintillation neutron detectors

    International Nuclear Information System (INIS)

    De, A.; Dasgupta, S.S.; Sen, D.

    1993-01-01

    Time dispersion (TD) has been computed for large neutron detectors using plastic scintillators. It has been shown that TD seen by the PM tube does not necessarily increase with incident neutron energy, a result not fully in agreement with the usual finding

  4. A new/old type of neutron spectrometer

    International Nuclear Information System (INIS)

    Vylet, V.; Fasso, A.; Luckau, N.

    1998-01-01

    The proposed portable spectrometer is a large sphere made of a plastic scintillator loaded with boron, possibly enriched with boron 10. The sphere is divided into spherical shells coated with a reflective or opaque material. Each shell is made of two hemispherical shells or smaller segments. Each segment is connected by a light-guide to a photomultiplier or a photodiode. It might be possible to use miniature photomultipliers directly embedded in detector layers. Each shell measures the thermal fluence at a different moderator depth and the set of shell responses can be used to unfold the original neutron spectrum, covering the range of energies from thermal to 20 MeV. (M.D.)

  5. Miniature Neutron-Alpha Activation Spectrometer

    Science.gov (United States)

    Rhodes, E.; Goldsten, J.

    2001-01-01

    We are developing a miniature neutron-alpha activation spectrometer for in situ analysis of samples including rocks, fines, ices, and drill cores, suitable for a lander or Rover platform, that would meet the severe mass, power, and environmental constraints of missions to the outer planets. In the neutron-activation mode, a gamma-ray spectrometer will first perform a penetrating scan of soil, ice, and loose material underfoot (depths to 10 cm or more) to identify appropriate samples. Chosen samples will be analyzed in bulk in neutron-activation mode, and then the sample surfaces will be analyzed in alpha-activation mode using Rutherford backscatter and x-ray spectrometers. The instrument will provide sample composition over a wide range of elements, including rock-forming elements (such as Na, Mg, Si, Fe, and Ca), rare earths (Sm and Eu for example), radioactive elements (K, Th, and U), and light elements present in water, ices, and biological materials (mainly H, C, O, and N). The instrument is expected to have a mass of about l kg and to require less than 1 W power. Additional information is contained in the original extended abstract.

  6. Spectrometer for neutron inelastic scattering investigations of microsamples

    International Nuclear Information System (INIS)

    Balagurov, A.M.; Kozlenko, D.P.; Platonov, S.L.; Savenko, B.N.; Glazkov, V.P.; Krasnikov, Yu.M.; Naumov, I.V.; Pukhov, A.V.; Somenkov, V.A.; Syrykh, G.F.

    1997-01-01

    A new neutron spectrometer for investigation of inelastic neutron scattering on polycrystal microsamples under high pressure in sapphire and diamond anvils cells is described. The spectrometer is operating at the IBR-2 pulsed reactor in JINR. Parameters and methodical peculiarities of the spectrometer and the examples of experimental studies are given. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-10-01

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

  8. Characterizing Scintillator Response with Neutron Time-of-Flight

    Science.gov (United States)

    Palmisano, Kevin; Visca, Hannah; Caves, Louis; Wilkinson, Corey; McClow, Hannah; Padalino, Stephen; Forrest, Chad; Katz, Joe; Sangster, Craig; Regan, Sean

    2017-10-01

    Neutron scintillator diagnostics for ICF can be characterized using the neutron time-of-flight (nTOF) line on Geneseo's 1.7 MV Tandem Pelletron Accelerator. Neutron signals can be differentiated from gamma signals by employing a coincidence method called the associated particle technique (APT). In this measurement, a 2.1 MeV beam of deuterons incident on a deuterated polyethylene target produces neutrons via the d(d,n)3He reaction. A BC-412 plastic scintillator, placed at a scattering angle of 152º, detects 1.76 MeV neutrons in coincidence with the 2.56 MeV 3He ions at an associated angle of 10º. The APT is used to identify the 1.76 MeV neutron while the nTOF line determines its energy. By gating only mono-energetic neutrons, the instrument response function of the scintillator can be determined free from background scattered neutrons and gamma rays. Funded in part by a Grant from the DOE, through the Laboratory for Laser Energetics.

  9. Deuterated scintillators and their application to neutron spectroscopy

    International Nuclear Information System (INIS)

    Febbraro, M.; Lawrence, C.C.; Zhu, H.; Pierson, B.; Torres-Isea, R.O; Becchetti, F.D.; Kolata, J.J.; Riggins, J.

    2015-01-01

    Deuterated scintillators have been used as a tool for neutron spectroscopy without Neutron Time-of-Flight (n-ToF) for more than 30 years. This article will provide a brief historical overview of the technique and current uses of deuterated scintillators in the UM-DSA and DESCANT arrays. Pulse-shape discrimination and spectrum unfolding with the maximum-likelihood expectation maximization algorithm will be discussed. Experimental unfolding and cross section results from measurements of (d,n), ( 3 He,n) and (α,n) reactions are shown

  10. Development of SCINFUL-CG code to calculate response functions of scintillators in various shapes used for neutron measurement

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Akira; Kim, Eunjoo; Yamaguchi, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-10-01

    A Monte Carlo code SCINFUL has been utilized for calculating response functions of organic scintillators for high-energy neutron spectroscopy. However, the applicability of SCINFUL is limited to the calculations for cylindrical NE213 and NE110 scintillators. In the present study, SCINFUL-CG was developed by introducing a geometry specifying function and high-energy neutron cross section data into SCINFUL. The geometry package MARS-CG, the extended version of the CG (Combinatorial Geometry), was programmed into SCINFUL-CG to express various geometries of detectors. Neutron spectra in the regions specified by the CG can be evaluated by the track length estimator. The cross section data of silicon, oxygen and aluminum for neutron transport calculation were incorporated up to 100 MeV using the data of LA150 library. Validity of SCINFUL-CG was examined by comparing calculated results with those by SCINFUL and MCNP and experimental data measured using high-energy neutron fields. SCINFUL-CG can be used for the calculations of the response functions and neutron spectra in the organic scintillators in various shapes. The computer code will be applicable to the designs of high-energy neutron spectrometers and neutron monitors using the organic scintillators. The present report describes the new features of SCINFUL-CG and explains how to use the code. (author)

  11. Performance of Large Neutron Detectors Containing Lithium-Gadolinium-Borate Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Slaughter, David M.; Stuart, Cory R.; Klaass, R. Fred; Merrill, David B. [MSI/Photogenics Division, Orem, Utah (United States)

    2015-07-01

    This paper describes the development and testing of a neutron counter, spectrometer, and dosimeter that is compact, efficient, and accurate. A self-contained neutron detection instrument has wide applications in health physics, scientific research, and programs to detect, monitor, and control strategic nuclear materials (SNM). The 1.3 liter detector head for this instrument is a composite detector with an organic scintillator containing uniformly distributed {sup 6}Li{sub 6}{sup nat}Gd{sup 10}B{sub 3}O{sub 9}:Ce (LGB:Ce) microcrystals. The plastic scintillator acts to slow impinging neutrons and emits light proportional to the energy lost by the neutrons as they moderate in the detector body. Moderating neutrons that have slowed sufficiently capture in one of the Lithium-6, Boron-10, or Gadolinium-157 atoms in the LGB:Ce scintillator, which then releases the capture energy in a characteristic cerium emission pulse. The measured captured pulses indicate the presence of neutrons. When a scintillating fluor is present in the plastic, the light pulse resulting from the neutron moderating in the plastic is paired with the LGB:Ce capture pulse to identify the energy of the neutron. About 2% of the impinging neutrons lose all of their energy in a single collision with the detector. There is a linear relationship between the pulse areas of this group of neutrons and energy. The other 98% of neutrons have a wide range of collision histories within the detector body. When these neutrons are 'binned' into energy groups, each group contains a distribution of pulse areas. This data was used to assist in the unfolding of the neutron spectra. The unfolded spectra were then validated with known spectra, at both neutron emitting isotopes and fission/accelerator facilities. Having validated spectra, the dose equivalent and dose rate are determined by applying standard, regulatory damage coefficients to the measured neutron counts for each energy bin of the spectra. Testing

  12. Response function measurement of plastic scintillator for high energy neutrons

    International Nuclear Information System (INIS)

    Sanami, Toshiya; Ban, Syuichi; Takahashi, Kazutoshi; Takada, Masashi

    2003-01-01

    The response function and detection efficiency of 2''φ x 2''L plastic (PilotU) and NE213 liquid (2''NE213) scintillators, which were used for the measurement of secondary neutrons from high energy electron induced reactions, were measured at Heavy Ion Medical Accelerator in Chiba (HIMAC). High energy neutrons were produced via 400 MeV/n C beam bombardment on a thick graphite target. The detectors were placed at 15 deg with respect to C beam axis, 5 m away from the target. As standard, a 5''φ x 5''L NE213 liquid scintillator (5''NE213) was also placed at same position. Neutron energy was determined by the time-of-flight method with the beam pickup scintillator in front of the target. In front of the detectors, veto scintillators were placed to remove charged particle events. All detector signals were corrected with list mode event by event. We deduce neutron spectrum for each detectors. The efficiency curves for pilotU and 2''NE213 were determined on the bases of 5 N E213 neutron spectrum and its efficiency calculated by CECIL code. (author)

  13. Calibration and intercomparison of neutron moderation spectrometers

    International Nuclear Information System (INIS)

    Rimpler, A.; Hermanska, J.; Prouza, Z.

    1989-01-01

    Results have been reported of comparative measurements of neutron fields from bare PuBe and Cf sources using multisphere (Bonner) spectrometers. The experiments were carried out by the Institute of Biophysics and Nuclear Medicine at Charles University in Prague and the National Board for Atomic Safety and Radiation Protection in Berlin. Both sides agreed upon uniform measuring conditions and calibration factors thus rendering possible the comparability of the dosimetric parameters which have been determined and verified, respectively, to an accuracy of ± 10%. 20 refs., 10 tabs., 2 figs. (author)

  14. Mechanical neutron spectrometer Chopper; Neutronski mehanicki spektrometar (coper)

    Energy Technology Data Exchange (ETDEWEB)

    Maglic, R [Institute of Nuclear Sciences Boris Kidric, Laboratorija za reaktorsku i neutronsku fiziku, Vinca, Beograd (Serbia and Montenegro)

    1961-12-15

    Construction of the neutron chopper was completed in 1961. This report covers both theoretical studies, calculation results and description of practical details related to design and construction of the mechanical neutron spectrometer.

  15. A variety of neutron sensors based on scintillating glass waveguides

    International Nuclear Information System (INIS)

    Bliss, M.; Craig, R.A.

    1995-05-01

    Pacific Northwest Laboratory (PNL) has fabricated cerium-activated, lithium-silicate glass scintillating fiber neutron sensors via a hot-downdraw process. These fibers typically have a transmission length (e -1 length) of greater than 2 meters. The underlying physics of, the properties of, and selected devices incorporating these fibers are described. These fibers constitute an enabling technology for a wide variety of neutron sensors

  16. Large solid-angle spectrometers for studies of double-differential charged-particle and neutron emission cross sections

    International Nuclear Information System (INIS)

    Baba, M.; Matsuyama, S.; Sanami, T.; Soda, D.; Matsuyama, I.; Ohkubo, T.; Iwasaki, S.; Hirakawa, N.

    1995-01-01

    The large solid-angle spectrometer developed for studies of double-differential cross sections of (n, charged particle) and (n, xn') reactions using a gas-filled gridded-ionization chamber and an 80-cm long liquid scintillator is described. The charged particle spectrometer is a twin gas-filled gridded-ionization chamber with solid angle close to 4 π designed to achieve high stopping power and background suppression. The neutron spectrometer is a long NE213 liquid scintillation detector having position sensitivity. It is used as a large single spectrometer or a position sensitive detector covering wide scattering angle. The facility design, performance and examples of application are discussed. The conclusion is made that the facility provides a useful mean for studies in particular for reactions with small cross sections and/or for neutron sources with low intensity. 15 refs., 15 figs

  17. Measuring neutron spectra in radiotherapy using the nested neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Maglieri, Robert, E-mail: robert.maglieri@mail.mcgill.ca; Evans, Michael; Seuntjens, Jan; Kildea, John [Medical Physics Unit, McGill University, Montreal, Quebec H4A 3J1 (Canada); Licea, Angel [Canadian Nuclear Safety Commission, Ottawa, Ontario K1P 5S9 (Canada)

    2015-11-15

    Purpose: Out-of-field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and an occupational risk to personnel during radiotherapy. To quantify neutron production, in-room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation foils and TLDs. In this work, a recently developed active detector, the nested neutron spectrometer (NNS), was tested in radiotherapy bunkers. Methods: The NNS is designed for easy handling and is more practical than the traditional BSS. Operated in current-mode, the problem of pulse pileup due to high dose-rates is overcome by measuring current, similar to an ionization chamber. In a bunker housing a Varian Clinac 21EX, the performance of the NNS was evaluated in terms of reproducibility, linearity, and dose-rate effects. Using a custom maximum-likelihood expectation–maximization algorithm, measured neutron spectra at various locations inside the bunker were then compared to Monte Carlo simulations of an identical setup. In terms of dose, neutron ambient dose equivalents were calculated from the measured spectra and compared to bubble detector neutron dose equivalent measurements. Results: The NNS-measured spectra for neutrons at various locations in a treatment room were found to be consistent with expectations for both relative shape and absolute magnitude. Neutron fluence-rate decreased with distance from the source and the shape of the spectrum changed from a dominant fast neutron peak near the Linac head to a dominant thermal neutron peak in the moderating conditions of the maze. Monte Carlo data and NNS-measured spectra agreed within 30% at all locations except in the maze where the deviation was a maximum of 40%. Neutron ambient dose equivalents calculated from the authors’ measured spectra were consistent (one standard deviation) with bubble detector measurements in the treatment room. Conclusions: The NNS may

  18. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    Energy Technology Data Exchange (ETDEWEB)

    Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Savici, Andrei T [ORNL; Garlea, Vasile O [ORNL; Winn, Barry L [ORNL; Schneelock, John [Brookhaven National Laboratory (BNL); Tranquada, John M. [Brookhaven National Laboratory (BNL); Gu, G. D. [Brookhaven National Laboratory (BNL); Wang, Aifeng [Brookhaven National Laboratory (BNL); Petrovic, C [Brookhaven National Laboratory (BNL)

    2017-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with the full polarization analysis. Examples of the polarized neutron diffraction and the polarized inelastic neutron data obtained on single crystal samples are presented.

  19. Polarized neutron scattering on HYSPEC: the HYbrid SPECtrometer at SNS

    OpenAIRE

    Zaliznyak, Igor A; Savici, Andrei T.; Garlea, V. Ovidiu; Winn, Barry; Filges, Uwe; Schneeloch, John; Tranquada, John M.; Gu, Genda; Wang, Aifeng; Petrovic, Cedomir

    2016-01-01

    We describe some of the first polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. We discuss details of the instrument setup and the experimental procedures in the mode with full polarization analysis. Examples of polarized neutron diffraction and polarized inelastic neutron data obtained on single crystal samples are presented.

  20. Investigation on neutron/gamma discrimination phenomena in plastic scintillators

    International Nuclear Information System (INIS)

    Blanc, Pauline

    2014-01-01

    This PhD topic was born from misunderstandings and incomplete knowledge of the mechanism and relative effectiveness of neutron and gamma-ray (n/γ) discrimination between plastic scintillators compared to liquid scintillators. The shape of the light pulse these materials generate following interaction with an ionizing particle (predominantly recoil protons in the case of neutrons and electrons in the case of gamma-rays) is different in time in a way that depends on the detected particle (nature and energy). It is this fact that enables separation (PSD). The behavior in liquid scintillators has been extensively studied experimentally for practical applications. Only recently has it been shown that a weak separation can also be achieved using specially prepared plastics. The study of this system presents an open field and the understanding of both liquids and plastics with respect to their PSD properties is far from complete. This work is dedicated to exploring the fundamental photophysical phenomena at play in the generation of luminescence emission, following the interaction of ionizing radiation with organic scintillators. For this purpose, firstly a detailed literature review of the state-of-the-art has been conducted extending from 1960 to the present day. Secondly a complete characterization of the main scintillating materials has been conducted to define their fluorescence properties and the characteristics of their scintillation under irradiation. Thirdly a proton beam has been used to simulate recoil protons to quantify under controlled laboratory conditions their specific energy deposition in a plastic scintillator with PSD properties. The fourth part of this thesis is devoted to the study of PSD efficiency of scintillators as a function of their molecular structure. This investigation has led to a plastic scintillator prepared in our laboratory with good PSD properties and a patent submission. Finally, photophysical experiments were performed using a

  1. Development of a Gamma Spectrometer using a Large NaI Scintillator and SiPMs

    International Nuclear Information System (INIS)

    Kim, Chankyu; Yoo, Hyunjun; Kim, Yewon and others

    2014-01-01

    A typical scintillation gamma spectrometer is composed of a NaI(Tl) scintillation crystal and a PM tube. From last years, a Silicon Photomultiplier (SiPM) is being developed and expanding its application area as a substitute of PM tube due to its advantages like low operating voltage, small volume, and cheap production cost, MR compatibility. This approach could make gamma spectrometer smaller, cheaper, easier to use, and these advantage are quite suitable to original purpose of scintillation gamma spectrometer. Gamma spectrometry and gamma spectrometer is used to analyze gamma source in nuclear science, geochemistry, and astrophysics. In this research, gamma spectrometer which uses SiPMs instead of PM tube is proposed. The proposed gamma spectrometer has advantages of low cost, small volume, low operation voltage; but it has disadvantages of performances. To reduce this loss in performances, a light guide of effective structure is required. (Material, reflection type, tapering angle) For design of the light guide, DETECT simulation was performed. And through DETECT simulation, the characteristics of light guide could be prospected. Actual light guide was manufactured on the basis of this simulation result. Using the light guide, gamma spectrometer system was composed and tested. In the test result, gamma spectrometer using SiPM shows degraded energy resolution. The reason of this degradation is being analyzed and the test system is under modification

  2. The VESUVIO electron volt neutron spectrometer

    Science.gov (United States)

    Mayers, J.; Reiter, G.

    2012-04-01

    This paper describes the VESUVIO electron volt neutron spectrometer at the ISIS pulsed neutron source and its data analysis routines. VESUVIO is used primarily for the measurement of proton momentum distributions in condensed matter systems, but can also be used to measure the kinetic energies of heavier masses and bulk in-situ sample compositions. A series of VESUVIO runs on the same zirconium hydride sample over the past two years show that (1) kinetic energies of protons can be measured to an absolute accuracy of ˜1%. (2) Measurements of the proton momentum distribution n(p) are highly reproducible from run to run. This shows that small changes in kinetic energy and the detailed shape of n(p) with parameters such as temperature, pressure and sample composition can be reliably extracted from VESUVIO data. (3) The impulse approximation (IA) is well satisfied on VESUVIO. (4) The small deviations from the IA due to the finite momentum transfer of measurement are well understood. (5) There is an anomaly in the magnitude of the inelastic neutron cross-section of the protons in zirconium hydride, with an observed reduction of 10% ± 0.3% from that given in standard tables. This anomaly is independent of energy transfer to within experimental error. Future instrument developments are discussed. These would allow the measurement of n(p) in other light atoms, D, 3He, 4He, Li, C and O and measurement of eV electronic and magnetic excitations.

  3. The VESUVIO electron volt neutron spectrometer

    International Nuclear Information System (INIS)

    Mayers, J; Reiter, G

    2012-01-01

    This paper describes the VESUVIO electron volt neutron spectrometer at the ISIS pulsed neutron source and its data analysis routines. VESUVIO is used primarily for the measurement of proton momentum distributions in condensed matter systems, but can also be used to measure the kinetic energies of heavier masses and bulk in-situ sample compositions. A series of VESUVIO runs on the same zirconium hydride sample over the past two years show that (1) kinetic energies of protons can be measured to an absolute accuracy of ∼1%. (2) Measurements of the proton momentum distribution n(p) are highly reproducible from run to run. This shows that small changes in kinetic energy and the detailed shape of n(p) with parameters such as temperature, pressure and sample composition can be reliably extracted from VESUVIO data. (3) The impulse approximation (IA) is well satisfied on VESUVIO. (4) The small deviations from the IA due to the finite momentum transfer of measurement are well understood. (5) There is an anomaly in the magnitude of the inelastic neutron cross-section of the protons in zirconium hydride, with an observed reduction of 10% ± 0.3% from that given in standard tables. This anomaly is independent of energy transfer to within experimental error. Future instrument developments are discussed. These would allow the measurement of n(p) in other light atoms, D, 3 He, 4 He, Li, C and O and measurement of eV electronic and magnetic excitations. (paper)

  4. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    Science.gov (United States)

    Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

    2016-11-29

    A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

  5. Suppression background device in neutron detection by a scintillation detector

    International Nuclear Information System (INIS)

    Degtyarev, A.P.; Kozyr', Yu.E.; Prokopets, G.A.

    1980-01-01

    A pulse shape discriminator for suppression of cosmic and gamma background as well as for suppression of intrinsic noises of a photomultiplier is described. Identification of signals of background and neutrons is performed by means of comparison of relative intensity of fast and slow components of scintillator luminescence. Basic discriminator flowsheet which contains integrating and differential RC circuits and time-to-amplitude converter is given. The discriminator provides minimum energy of detected neutrons equal to 500 keV when using a FEhU-36 neutron detector with a stilbene crystal [ru

  6. Red Emitting Phenyl-Polysiloxane Based Scintillators for Neutron Detection

    International Nuclear Information System (INIS)

    Dalla Palma, Matteo; Quaranta, Alberto; Marchi, Tommaso; Gramegna, Fabiana; Cinausero, Marco; Carturan, Sara; Collazuol, Gianmaria

    2013-06-01

    In this work, the performances of new red emitting phenyl- substituted polysiloxane based scintillators are described. Three dyes were dispersed in a phenyl-polysiloxane matrix in order to shift the scintillation wavelength towards the red part of the visible spectrum. PPO, Lumogen Violet (BASF) and Lumogen Red (BASF) were mixed to the starting resins with different wt. % and the analysis of the different samples was performed by means of fluorescence measurements. The scintillation yield to alpha particles at the different dye ratios was monitored by detecting either the full spectrum or the red part of the emitted light. Finally, thin red scintillators with selected compositions were coupled to Avalanche Photodiode sensors, which are usually characterized by higher efficiency in the red part of the spectrum. An increased light output of about 17% has been obtained comparing the red scintillators to standard blue emitting systems. Preliminary results on the detection of fast neutrons with the APD-red scintillator system are also presented. (authors)

  7. Linear position sensitive neutron detector using fiber optic encoded scintillators

    International Nuclear Information System (INIS)

    Davidson, P.L.; Wroe, H.

    1983-01-01

    A linear position sensitive slow neutron detector with 3 mm resolution is described. It uses the fiber optic coding principle in which the resolution elements are separate pieces of lithium loaded glass scintillator each coupled by means of flexible polymer optical fibers to a unique combination of 3 photo multipliers (PM's) out of a bank of 12. A decoder circuit repsponds to a triple coincidence between PM outputs and generates a 12 bit work which identifies the scintillator element which stopped the incident neutron. Some details of the construction and decoding electronics are given together with test results obtained using a laboratory isotope neutron source and a monochomated, collimated neutron beam from a reactor. The count rate in the absence of neutron sources is 2 to 3 c min - 1 per element; the element to element variation in response to a uniform flux is a few percent for 95% of the elements; the resolution as measured by a 1 mm wide prode neutron beam is 3 mm; the relative long term stability is about 0.1% over 3 days and the detection efficiency measured by comparison with an end windowed, high pressure gas counter is about 65% at a neutron wavelength of 0.9A 0

  8. Lithium indium diselenide: A new scintillator for neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lukosi, Eric, E-mail: elukosi@utk.edu [University of Tennessee, Knoxville, TN (United States); Herrera, Elan; Hamm, Daniel; Lee, Kyung-Min [University of Tennessee, Knoxville, TN (United States); Wiggins, Brenden [Y-12 National Security Complex, Oak Ridge, TN (United States); Trtik, Pavel [Paul Scherrer Institut, Villigen CH-5232 (Switzerland); Penumadu, Dayakar; Young, Stephen [University of Tennessee, Knoxville, TN (United States); Santodonato, Louis; Bilheux, Hassina [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Burger, Arnold; Matei, Liviu [Fisk University, Nashville, TN (United States); Stowe, Ashley C. [University of Tennessee, Knoxville, TN (United States); Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-11

    Lithium indium diselenide, {sup 6}LiInSe{sub 2} or LISe, is a newly developed neutron detection material that shows both semiconducting and scintillating properties. This paper reports on the performance of scintillating LISe crystals for its potential use as a converter screen for cold neutron imaging. The spatial resolution of LISe, determined using a 10% threshold of the Modulation Transfer Function (MTF), was found to not scale linearly with thickness. Crystals having a thickness of 450 µm or larger resulted in an average spatial resolution of 67 µm, and the thinner crystals exhibited an increase in spatial resolution down to the Nyquist frequency of the CCD. The highest measured spatial resolution of 198 µm thick LISe (27 µm) outperforms a commercial 50 µm thick ZnS(Cu):{sup 6}LiF scintillation screen by more than a factor of three. For the LISe dimensions considered in this study, it was found that the light yield of LISe did not scale with its thickness. However, absorption measurements indicate that the {sup 6}Li concentration is uniform and the neutron absorption efficiency of LISe as a function of thickness follows general nuclear theory. This suggests that the differences in apparent brightness observed for the LISe samples investigated may be due to a combination of secondary charged particle escape, scintillation light transport in the bulk and across the LISe-air interface, and variations in the activation of the scintillation mechanism. Finally, it was found that the presence of {sup 115}In and its long-lived {sup 116}In activation product did not result in ghosting (memory of past neutron exposure), demonstrating potential of LISe for imaging transient systems.

  9. Development of a BaF2 scintillation spectrometer for evaluation of photon energy spectra in workplaces around nuclear facilities

    International Nuclear Information System (INIS)

    Urabe, Itsumasa; Yoshimoto, Taka-aki; Kobayashi, Katsuhei; Akiyoshi, Tsunekazu; Tsujimoto, Tadashi; Nakashima, Yoshiyuki; Oda, Keiji.

    1997-01-01

    A BaF 2 scintillation spectrometer has been constructed for the determination of photon energy spectra in workplaces around nuclear facilities. Energy absorption spectra by the BaF 2 detector were calculated with the EGS4 Monte Carlo code in the energy region from 0.1 to 100 MeV and a response matrix of the spectrometer was obtained from the energy absorption spectra, of which the energy resolutions were modified to fit to the experimental results. With the irradiation experiments using neutron-capture gamma rays and those from radioactive sources, it became clear that photon energy spectra can be evaluated within an error of about 10% in the energy region 0.1 MeV to a few tens of megaelectronvolts. (author)

  10. Comparison of Americium-Beryllium neutron spectrum obtained using activation foil detectors and NE-213 spectrometer

    International Nuclear Information System (INIS)

    Sunny, Sunil; Subbaiah, K.V.; Selvakumaran, T.S.

    1999-01-01

    Neutron spectrum of Americium - Beryllium (α,n) source is measured with two different spectrometers vis-a-vis activation foils (foil detectors) and NE-213 organic scintillator. Activity induced in the foils is measured with 4π-β-γ sodium iodide detector by integrating counts under photo peak and the saturation activity is found by correcting to elapsed time before counting. The data on calculated activity is fed into the unfolding code, SAND-II to obtain neutron spectrum. In the case of organic scintillator, the pulse height spectrum is obtained using MCA and this is processed with unfolding code DUST in order to get neutron spectrum. The Americium - Beryllium (α,n) neutron spectrum thus obtained by two different methods is compared. It is inferred that the NE-213 scintillator spectrum is in excellent agreement with the values beyond 1MeV. Neutron spectrum obtained by activation foils depends on initial guess spectrum and is found to be in reasonable agreement with NE-213 spectrum. (author)

  11. Neutron Detection with Large Plastic Scintillators for RPM Applications

    International Nuclear Information System (INIS)

    Corre, G.; Boudergui, K.; Sannie, G.; Kondrasovs, V.

    2015-01-01

    Homeland security requests the use Radiation Portal Monitor (RPM). They must be able to detect and differentiate gamma and neutron radiation. Gamma detection is required for illicit transportation of radioactive matter detection. Neutron detection is important to control nonproliferation of enriched material. Manufacturers worldwide propose sensors based on 3 He which give the actual state of art in term of neutron detection. The imminent shortage of 3 He forces manufacturers to find viable alternative. From 10 years sensors providers have the challenge to replace previous 3 He detectors that are known to be the most commonly deployed neutron sensor. As 3 He detectors can only detect neutron, they must be completed with gamma detector. The proposed approach is based on pulse time correlation between adjacent sensors from signal collected by EJ200 plastic scintillators. Results obtained during FP7 Scintilla project test campaigns show the system relevance for replacement of today's 3 He detectors. (authors)

  12. New Organic Scintillators for Neutron Detection

    Science.gov (United States)

    2016-03-01

    gamma rays. For heterogeneous or dense materials such as samples of metals , oxides , and nuclear waste, gamma ray attenuation can be too high to...highly enriched uranium and weapons grade plutonium. Neutrons and gamma rays are two signatures of these materials. Gamma ray detection techniques are... uranium ). Thus, neutron detection is an important component of the overall detection techniques used in identifying SNMs. Important requirements for

  13. MESSENGER E/V/H GRNS 3 NEUTRON SPECTROMETER CDR V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — Abstract ======== This data set consists of the MESSENGER Neutron Spectrometer (NS) calibrated data records (CDRs). The NS experiment is a neutron spectrometer...

  14. A compound parabolic concentrator as an ultracold neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Hickerson, K.P., E-mail: hickerson@gmail.com; Filippone, B.W., E-mail: bradf@caltech.edu

    2013-09-01

    The design principles of nonimaging optics are applied to ultracold neutrons (UCN). In particular a vertical compound parabolic concentrator (CPC) that efficiently redirects UCN vertically into a bounded spatial volume where they have a maximum energy mga that depends only on the initial phase space cross sectional area πa{sup 2} creates a spectrometer which can be applied to neutron lifetime and gravitational quantum state experiments. -- Highlights: • Nonimaging optics is applied to ultracold neutrons. • A novel ultracold neutron spectrometer is discussed. • New uses may include a neutron lifetime experiment.

  15. A compound parabolic concentrator as an ultracold neutron spectrometer

    International Nuclear Information System (INIS)

    Hickerson, K.P.; Filippone, B.W.

    2013-01-01

    The design principles of nonimaging optics are applied to ultracold neutrons (UCN). In particular a vertical compound parabolic concentrator (CPC) that efficiently redirects UCN vertically into a bounded spatial volume where they have a maximum energy mga that depends only on the initial phase space cross sectional area πa 2 creates a spectrometer which can be applied to neutron lifetime and gravitational quantum state experiments. -- Highlights: • Nonimaging optics is applied to ultracold neutrons. • A novel ultracold neutron spectrometer is discussed. • New uses may include a neutron lifetime experiment

  16. Next Generation Neutron Scintillators Based On Semiconductor Nanostructures

    International Nuclear Information System (INIS)

    Wang, Cai-Lin

    2008-01-01

    The results reported here successfully demonstrate the technical feasibility of ZnS QDs/ 6 LiF/polymer composites as thermal neutron scintillators. PartTec has obtained stable ZnS QDs with a quantum yield of 17% induced by UV light, and light pulse decay lifetimes of 10-30 ns induced by both UV and neutrons. These lifetime values are much shorter than those of commercial ZnS microparticle and 6 Li-glass scintillators. Clear pulse height peaks induced by neutron irradiation were seen for PartTec's ZnS nanocomposites. By adjusting the concentrations, particle size and degree of dispersion of ZnS QD/ 6 LiF in a PVA matrix, the light absorption and light yield of films at 420-440 nm can be optimized. PartTec's novel scintillators will replace traditional 6 Li-glass and ZnS/ 6 LiF:Ag scintillators if the PL quantum yield can be improved above 30%, and/or increase the transparency of present nanoscintillators. Time and resources inhibited PartTec's total success in Phase I. For example, bulk doping preparations of ZnS QDs with Ag + , Eu 3+ or Ce 3+ QDs was impractical given those constraints, nor did they permit PartTec to measure systematically the change of PL decay lifetimes in different samples. PartTec will pursue these studies in the current proposal, as well as develop a better capping and dopant along with developing brighter and faster ZnS QD scintillators.

  17. System and plastic scintillator for discrimination of thermal neutron, fast neutron, and gamma radiation

    Science.gov (United States)

    Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.; Glenn, Andrew M.; Martinez, H. Paul; Pawelczak, Iwona A.; Payne, Stephen A.

    2017-05-16

    A scintillator material according to one embodiment includes a polymer matrix; a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 3 wt % or more; and at least one component in the polymer matrix, the component being selected from a group consisting of B, Li, Gd, a B-containing compound, a Li-containing compound and a Gd-containing compound, wherein the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays. A system according to one embodiment includes a scintillator material as disclosed herein and a photodetector for detecting the response of the material to fast neutron, thermal neutron and gamma ray irradiation.

  18. Feasibility of the Precise Energy Calibration for Fast Neutron Spectrometers

    Science.gov (United States)

    Gaganov, V. V.; Usenko, P. L.; Kryzhanovskaja, M. A.

    2017-12-01

    Computational studies aimed at improving the accuracy of measurements performed using neutron generators with a tritium target were performed. A measurement design yielding an extremely narrow peak in the energy spectrum of DT neutrons was found. The presence of such a peak establishes the conditions for precise energy calibration of fast-neutron spectrometers.

  19. Development of triple axis neutron spectrometer (Paper No. 24)

    International Nuclear Information System (INIS)

    Pal, B.C.; Wadhwa, N.R.; Goveas, S.H.

    1987-02-01

    The triple axis neutron spectrometers are the basic instruments intended for use with neutron beams from reactors. Various types of spectrometers, each devoted to different kinds of measurement can be designed and manufactured, once a prototype having all the attributes of a versatile instrument is designed and developed. With the view to achieving self reliance in this field, Central Workshops of Bhabha Atomic Research Centre (BARC), Bombay designed and developed a prototype of triple axis spectrometer meeting the specifications prepared by Nuclear Physics Division of BARC . This spectrometer, with a moving wedge system was successfully manufactured and installed at 'DHRUVA'. Another version of this spectrometer, called the 'Polarised Neutron Spectrometer' was also built and exported to South Korea and installed at Korea Advanced Energy Research Institute, Seoul. This paper deals with basic concept, development of design, engineering of mechanical assemblies, the manufacturing approach and problems encountered during manufacture. (author). 3 figs

  20. Transparent plastic scintillators for neutron detection based on lithium salicylate

    International Nuclear Information System (INIS)

    Mabe, Andrew N.; Glenn, Andrew M.; Carman, M. Leslie; Zaitseva, Natalia P.; Payne, Stephen A.

    2016-01-01

    Transparent plastic scintillators with pulse shape discrimination containing "6Li salicylate have been synthesized by bulk polymerization with a maximum "6Li loading of 0.40 wt%. Photoluminescence and scintillation responses to gamma-rays and neutrons are reported herein. Plastics containing "6Li salicylate exhibit higher light yields and permit a higher loading of "6Li as compared to previously reported plastics based on lithium 3-phenylsalicylate. However, pulse shape discrimination performance is reduced in lithium salicylate plastics due to the requirement of adding more nonaromatic monomers to the polymer matrix as compared to those based on lithium 3-phenylsalicylate. Reduction in light yield and pulse shape discrimination performance in lithium-loaded plastics as compared to pulse shape discrimination plastics without lithium is interpreted in terms of energy transfer interference by the aromatic lithium salts. - Highlights: • Plastic scintillator with 0.4% "6Li loading is reported using lithium salicylate. • Influence of lithium salts on the scintillation mechanism is explored. • New lithium-loaded scintillator provides improved light yield and reduced cost.

  1. Feasibility study of a SiC sandwich neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian, E-mail: caepwujian@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Lei, Jiarong, E-mail: jiarong_lei@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Jiang, Yong; Chen, Yu; Rong, Ru; Zou, Dehui; Fan, Xiaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Chen, Gang; Li, Li; Bai, Song [Nanjing Electronic Devices Institute, Nanjing 210016 (China)

    2013-04-21

    Semiconductor sandwich neutron spectrometers are suitable for in-pile measurements of fast reactor spectra thanks to their compact and relatively simple design. We have assembled and tested a sandwich neutron spectrometer based on 4H-silicon carbide (4H-SiC) Schottky diodes. The SiC diodes detect neutrons via neutron-induced charged particles (tritons and alpha particles) produced by {sup 6}Li(n,α){sup 3}H reaction. {sup 6}LiF neutron converter layers are deposited on the front surface of Schottky diodes by magnetron sputtering. The responses of SiC diodes to charged particles were investigated with an {sup 241}Am alpha source. A sandwich neutron spectrometer was assembled with two SiC Schottky diodes selected based on the charged-particle-response experimental results. The low-energy neutron response of the sandwich spectrometer was measured in the neutron field of the Chinese Fast Burst Reactor-II (CFBR-II). Spectra of alpha particles and tritons from {sup 6}Li(n,α){sup 3}H reaction were obtained with two well-resolved peaks. The energy resolution of the sum spectrum was 8.8%. The primary experimental results confirmed the 4H-SiC sandwich neutron spectrometer's feasibility. -- Highlights: ► Sandwich neutron spectrometer employing 4H-SiC as a detecting material has been developed for the first time. ► {sup 6}LiF neutron converter has been deposited on the surface of 4H-SiC Schottky diode. ► Preliminary testing results obtained with the 4H-SiC sandwich neutron spectrometer are presented.

  2. Technique investigation on large area neutron scintillation detector array

    International Nuclear Information System (INIS)

    Chen Jiabin

    2006-12-01

    The detailed project for developing Large Area Neutron Scintillation Detector Array (LaNSA) to be used for measuring fusion fuel area density on Shenguang III prototype is presented, including experimental principle, detector working principle, electronics system design and the needs for target chamber etc. The detailed parameters for parts are given and the main causes affecting the system function are analyzed. The realization path is introduced. (authors)

  3. Evaluation of 1cm dose equivalent rate using a NaI(Tl) scintilation spectrometer

    International Nuclear Information System (INIS)

    Matsuda, Hideharu

    1990-01-01

    A method for evaluating 1 cm dose equivalent rates from a pulse height distribution obtained by a 76.2mmφ spherical NaI(Tl) scintillation spectrometer was described. Weak leakage radiation from nuclear facilities were also measured and dose equivalent conversion factor and effective energy of leakage radiation were evaluated from 1 cm dose equivalent rate and exposure rate. (author)

  4. Study of the functional characteristics of a NaI(Tl) scintillator gamma spectrometer

    International Nuclear Information System (INIS)

    Jesus Barbosa, S. de.

    1983-01-01

    Functional characteristics (resolution, stability, linearity, counting efficiency) of a NaI(Tl) scintillator gamma spectrometer were studied. Diagrams were plotted and several standard sources ( 241 Am, 109 Cd, 57 Co, 137 Cs, 54 Mn, 22 Na) with gamma energies ranging from 60 to 1275 KeV were used. (C.L.B.) [pt

  5. Polarized neutron spectrometer for inelastic experiments at J-PARC

    Directory of Open Access Journals (Sweden)

    Yokoo Tetsuya

    2015-01-01

    Full Text Available Construction of the newly developed polarization analysis neutron chopper spectrometer (POLANO commenced in the Japan Proton Accelerator Research Complex (J-PARC, Materials and Life Science Experimental Facility (MLF. The POLANO is a direct geometry chopper spectrometer with neutron polarization analysis capability. In the suite of inelastic spectrometers, six instruments are now in operation. POLANO will be the only spectrometer dedicated to polarization analysis experiments. The primary phase of the construction will be completed by 2014 with beam commissioning scheduled for 2015.

  6. Optimization of cocktail volume in estimation of Tritium activity using liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Kumaravel, S.; Narashimha Nath, V.; Prashanth Kumar, M.; Sunil, C.N.; Raghunath, T.; Bera, Utpal; Ramakrishna, V.; Nair, B.S.K.; Ganesh, G.; Tripathi, R.M.

    2016-01-01

    Liquid Scintillation Spectrometers (LSS) are widely used for the estimation of Tritium in Nuclear Industry and Environmental labs to find out the Tritium concentration. The main component used for the detection of tritium is the liquid scintillation cocktail composed of different chemicals. To reduce the radioactive chemical wastes and the cost of liquid scintillation cocktails the use of as small volume of cocktail as possible is required. Typically, 1 ml of the aqueous sample is added with 5 ml of the liquid scintillation cocktail in a 20 ml low potassium glass. In this study, suitability of the combination of I ml aqueous sample with 2.5 ml cocktail in a 7 ml low potassium glass vial using a HIDEX 300 SL TDCR LSS was carried out instead of the other combination

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

    International Nuclear Information System (INIS)

    Goodman, C.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. 3 claims

  8. Analysis of the scintillation mechanism in a pressurized 4He fast neutron detector using pulse shape fitting

    Directory of Open Access Journals (Sweden)

    R.P. Kelley

    2015-03-01

    Full Text Available An empirical investigation of the scintillation mechanism in a pressurized 4He gas fast neutron detector was conducted using pulse shape fitting. Scintillation signals from neutron interactions were measured and averaged to produce a single generic neutron pulse shape from both a 252Cf spontaneous fission source and a (d,d neutron generator. An expression for light output over time was then developed by treating the decay of helium excited states in the same manner as the decay of radioactive isotopes. This pulse shape expression was fitted to the measured neutron pulse shape using a least-squares optimization algorithm, allowing an empirical analysis of the mechanism of scintillation inside the 4He detector. A further understanding of this mechanism in the 4He detector will advance the use of this system as a neutron spectrometer. For 252Cf neutrons, the triplet and singlet time constants were found to be 970 ns and 686 ns, respectively. For neutrons from the (d,d generator, the time constants were found to be 884 ns and 636 ns. Differences were noted in the magnitude of these parameters compared to previously published data, however the general relationships were noted to be the same and checked with expected trends from theory. Of the excited helium states produced from a 252Cf neutron interaction, 76% were found to be born as triplet states, similar to the result from the neutron generator of 71%. The two sources yielded similar pulse shapes despite having very different neutron energy spectra, validating the robustness of the fits across various neutron energies.

  9. Analysis of mean lifetime for capture of neutrons in boron-loaded plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Kamykowski, E.A. (Grumman Corp., Bethpage, NY (USA). Research Center)

    1990-12-20

    The commercial availabiltiy of boron-loaded organic scintillators has led to the development of neutron detectors that operate as ''electronically'' black, totally absorbing spectrometers. The key to the enhanced spectroscopy is the delayed capture of nearly thermalized neutrons by {sup 10}B that can occur within a few microseconds after the energy pulse from prompt proton recoils. Accurate information regarding the mean lifetime is important for correct setting of the timing logic of the detection system to obtain good neutron detection efficiency with a low chance coincidence rate. In this paper we present an analysis of the mean lifetime for neutron capture for the boron-loaded plastic BC454. Measurements of the capture time constant obtained with a 7.62 cm diameter, 10.16 cm long detector are compared with values computed with the time-dependent Monte Carlo neutron transport code MCNP. Additional analyses using MCNP examine the dependence of the mean lifetime on the boron concentration, the detector's dimensions and the incident neutron energy. (orig.).

  10. Experimental research of plastic scintillation detector loaded 6Li neutron energy response

    International Nuclear Information System (INIS)

    Wang Lizong; Zhang Chuanfei; Peng Taiping; Guo Cun; Yang Hongqiong; Zhang Jianhua

    2005-01-01

    A new plastic scintillator, plastic scintillator loaded 6 Li, is brought forward and developed in this paper in order to increase low energy neutron sensitivity. Neutron sensitivity of several plastic scintillation detectors loaded 6 Li new developed in neutron energy range 0.2 MeV-5.0 MeV are calibrated by direct current at serial accelerator. Energy response curves of the detectors are obtained in this experiment. It is shown that this new plastic scintillation detector can increase low energy neutron sensitivity in experimental results. (authors)

  11. A Double Slow Neutron Spectrometer; Spectrometre double pour neutrons lents; Dvojnoj spektrometr medlennykh nejtronov; Espectrometro doble para neutrones lentos

    Energy Technology Data Exchange (ETDEWEB)

    Bondarenko, I I; Liforov, V G; Nikolaev, M N; Orlov, V V; Parfenov, V A; Semenov, V A; Smirnov, V I; Turchin, V F [Fehi, Moscow, SSSR (Russian Federation)

    1963-01-15

    The neutron spectrometer described in the paper is intended for measurements of the angular and energy distribution of monochromatic slow neutrons, inelasticaily scattered by liquid and solid bodies. Experiments of this type permit detailed information to be obtained concerning the dynamics of the atoms in various aggregate states of a substance. The spectromeeter is based on the time-of-flight method. The pulse source of neutrons is the IBR (1) reactor. A mechanical interrupter, rotating synchronously with the disc of the IBR and having a prescribed phase shift, serves as the monochromator. A special phasing system ensures a phasee stability better than 0.5{sup o}. The neutrons scattered by the sample are recorded by a scintillation detector set at a given angle to the neutron beam. The resolving power of the spectrometer is - 15 {mu}s/m. The paper gives a detailed description of the construction of the spectroscope and its characteristics. (author) [French] Le spectrometre neutronique decrit dans le memoire est destine a mesurer la distribution en energie, la distribution angulaire et la diffusion inelastique des neutrons lents monochromatiques dans des liquides et des solides. Les experiences de ce genre permettent d'obtenir des renseignements detailles sur la dynamique des atomes dans de divers etats de la matiere. Le spectrometre est fonde sur la mesure du temps de vol. Comme source puisee de neutrons on a utilise le reacteur IBR-1. Le systeme monochromateur etait constitue par un interrupteur mecanique en rotation synchronisee avec celle du disque du reacteur IBR, avec un dephasage determine. Un dispositif special de dephasage assure la stabilite de la phase a 0,5{sup o} pres. La diffusion des neutrons par l'echantillon est enregistree a l'aide d'un detecteur a scintillations dispose sous un angle determine par rapport au faisceau de neutrons. Le pouvoir de resolution du spectrometre est d'environ 15 {mu}s/m. Les auteurs decrivent en detail la construction du

  12. An improved computer controlled triple-axis neutron spectrometer

    International Nuclear Information System (INIS)

    Cooper, M.J.; Hall, J.W.; Hutchings, M.T.

    1975-07-01

    A description is given of the computer-controlled triple-axis neutron spectrometer installed at the PLUTO reactor at Harwell. The reasons for an nature of recent major improvements are discussed. Following a general description of the spectrometer, details are then given of the new computerised control system, including the functions of the various programs which are now available to the user. (author)

  13. Multichannel analyzer for the neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Vojter, A.P.; Slyisenko, V.Yi.; Doronyin, M.Yi.; Maznij, Yi.O.; Vasil'kevich, O.A.; Golyik, V.V.; Koval'ov, O.M.; Kopachov, V.Yi.; Savchuk, V.G.

    2010-01-01

    New multichannel time-of-flight spectrometer for the measurement of the energy and angular distributions of neutrons from the WWWR-M reactor is considered. This spectrometer has been developed for the replacement of the previous one to increase the number of channels and measurement precision, reduce the time of channel tuning and provide the automatic monitoring during the experiment.

  14. High resolution 14 MeV neutron spectrometer

    International Nuclear Information System (INIS)

    Pillon, M.

    1986-01-01

    A neutron spectrometer, based both on the track position identification and the energy measurement of recoiling protons from a hydrogenous radiator is proposed. The expected performance limits of this spectrometer with regard to energy resolution (deltaE/E), efficiency (epsilon) and counting rate are evaluated in five different configurations. The results show the possibility of deriving an optimized spectrometer design for applications on large fusion devices such as JET and NET with an energy resolution up 1% at 14 MeV

  15. Two-dimensional neutron scintillation detector with optimal gamma discrimination

    International Nuclear Information System (INIS)

    Kanyo, M.; Reinartz, R.; Schelten, J.; Mueller, K.D.

    1993-01-01

    The gamma sensitivity of a two-dimensional scintillation neutron detector based on position sensitive photomultipliers (Hamamatsu R2387 PM) has been minimized by a digital differential discrimination unit. Since the photomultiplier gain is position-dependent by ±25% a discrimination unit was developed where digital upper and lower discrimination levels are set due to the position-dependent photomultiplier gain obtained from calibration measurements. By this method narrow discriminator windows can be used to reduce the gamma background drastically without effecting the neutron sensitivity of the detector. The new discrimination method and its performance tested by neutron measurements will be described. Experimental results concerning spatial resolution and γ-sensitivity are presented

  16. Calibration of a compact magnetic proton recoil neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianfu, E-mail: zhang_jianfu@163.com [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Ouyang, Xiaoping; Zhang, Xianpeng [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Ruan, Jinlu [Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Zhang, Guoguang [Applied Institute of Nuclear Technology, China Institute of Atomic Energy, Beijing 102413 (China); Zhang, Xiaodong [Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Qiu, Suizheng, E-mail: szqiu@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Liang; Liu, Jinliang; Song, Jiwen; Liu, Linyue; Yang, Shaohua [Northwest Institute of Nuclear Technology, Xi' an 710024 (China)

    2016-04-21

    Magnetic proton recoil (MPR) neutron spectrometer is considered as a powerful instrument to measure deuterium–tritium (DT) neutron spectrum, as it is currently used in inertial confinement fusion facilities and large Tokamak devices. The energy resolution (ER) and neutron detection efficiency (NDE) are the two most important parameters to characterize a neutron spectrometer. In this work, the ER calibration for the MPR spectrometer was performed by using the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), and the NDE calibration was performed by using the neutron generator at CIAE. The specific calibration techniques used in this work and the associated accuracies were discussed in details in this paper. The calibration results were presented along with Monte Carlo simulation results.

  17. Application of MSS-neutron spin echo spectrometer to pulsed neutron sources

    International Nuclear Information System (INIS)

    Tasaki, S.; Ebisawa, T.; Hino, M.; Kawai, T.

    2001-01-01

    A multilayer spin splitter (MSS) is a neutron device that gives phase difference between field-parallel and -antiparallel spin component of a superposing state. Since the phase difference is equivalent to the Larmor precession angle, MSS enables us to construct a new type of neutron spin echo (NSE) spectrometer. The new NSE spectrometer has its properties that 1. since the phase shift is neutron flight path length, the spectrometer can be drastically small, 2. the neutron spin echo time is proportional to the neutron wavelength. (author)

  18. Development of the Brazilian national sheet scintillator converter of neutron

    International Nuclear Information System (INIS)

    Barbosa, Andre Luis Nunes

    2008-03-01

    Both the national domain of the technology for the separation of rare earth elements and the large reserves of these minerals in Brazilian territory, motivated the study of national sheets scintillators converter of neutrons, using a granular mixture Gd 2 O 3 -Zn S:Ag. Three methodologies were used for the manufacture of such sheets, namely: deposition done with a compressed-air gun on a sheet of cellulose type CG3460-3M; fusion of granular mixture with EVA in the mixing chamber and deposition of granular mixture on the substrate of EVA. It was used the flux of the order of 4,46 x 10 5 neutrons thermic/cm 2 .s, coming from the channel irradiation, J-9, of the reactor Argonauta/IEN/CNEN and the radiographic film AA-400 Kodak Industrex. The performances of national scintillator neutrons converter sheets were analyzed and the images obtained with the, demonstrated that the methodologies proposed are technically feasible and can contribute to the reduction of cost of this technique for NDA, but which lack optimization is aimed at increasing the number of photons of light to allow its use in neutrongraphies in Real Time (NRTR). (author)

  19. Evaluation of response matrix of a multisphere neutron spectrometer ...

    Indian Academy of Sciences (India)

    Abstract. Neutron energy responses of water sphere spectrometers (WSS) to 30 MeV have been calculated by means of Monte Carlo calculations, using the computer code MCNP4C with ENDF/. B-VI.0 neutron cross-section. The calculations have been performed for 3He detector (typical SP9) placed inside 2, 3, 5, 8, ...

  20. Superresolution of a compact neutron spectrometer at energies relevant for fusion diagnostics

    International Nuclear Information System (INIS)

    Reginatto, M.; Zimbal, A.

    2011-01-01

    The ability to achieve resolution that is better than the instrument resolution (i.e., superresolution) is well known in optics, where it has been extensively studied. Unfortunately, there are only a handful of theoretical studies concerning superresolution of particle spectrometers, even though experimentalists are familiar with the enhancement of resolution that is achievable when appropriate methods of data analysis are used, such as maximum entropy and Bayesian methods. Knowledge of the superresolution factor is in many cases important. For example, in applications of neutron spectrometry to fusion diagnostics, the temperature of a burning plasma is an important physical parameter which may be inferred from the width of the peak of the neutron energy spectrum, and the ability to determine this width depends on the superresolution factor. Kosarev has derived an absolute limit for resolution enhancement using arguments based on a well known theorem of Shannon. Most calculations of superresolution factors in the literature, however, are based on the assumption of Gaussian, translationally invariant response functions and therefore not directly applicable to neutron spectrometers which typically have response functions not satisfying these requirements. In this work, we develop a procedure that allows us to overcome these difficulties and we derive estimates of superresolution for liquid scintillator spectrometers of a type commonly used for neutron measurements. Theoretical superresolution factors are compared to experimental results.

  1. 4D space access neutron spectrometer 4SEASONS (SIKI)

    International Nuclear Information System (INIS)

    Kajimoto, Ryoichi; Nakamura, Mitsutaka

    2010-01-01

    The 4D Space Access Neutron Spectrometer (4SEASONS) is a high-intensity Fermi-chopper spectrometer. It is intended to provide high counting rate for thermal neutrons with medium resolution (ΔE/E i -6% at E=0) to efficiently collect weak inelastic signals from novel spin and lattice dynamics especially in high-T c superconductors and related materials. To achieve this goal, the spectrometer equips advanced instrumental design such as an elliptic-shaped converging neutron guide coated with high-Q c (m=3-4) supermirror, and long-length (2.5 m) 3 He position sensitive detectors (PSDs) arranged cylindrically inside the vacuum scattering chamber. Furthermore, the spectrometer is ready for multi-incident-energy measurements by the repetition rate multiplication method, which greatly improves the measurement efficiency. (author)

  2. The neutron spin-echo spectrometer: a new high resolution technique in neutron scattering

    International Nuclear Information System (INIS)

    Nicholson, L.K.

    1981-01-01

    The neutron spin-echo (NSE) spectrometer provides the highest energy resolution available in neutron scattering experiments. The article describes the principles behind the first NSE spectrometer (at the Institute Laue-Langevin, Grenoble, France) and, as an example of one of its applications, some recent results on polymer chain dynamics are presented. (author)

  3. Study on calibration of neutron efficiency and relative photo-yield of plastic scintillator

    International Nuclear Information System (INIS)

    Peng Taiping; Zhang Chuanfei; Li Rurong; Zhang Jianhua; Luo Xiaobing; Xia Yijun; Yang Zhihua

    2002-01-01

    A method used for the calibration of neutron efficiency and the relative photo yield of plastic scintillator is studied. T(p, n) and D(d, n) reactions are used as neutron resources. The neutron efficiencies and the relative photo yields of plastic scintillators 1421 (40 mm in diameter and 5 mm in thickness) and determined in the neutron energy range of 0.655-5 MeV

  4. Measurement of the neutron detection efficiency of a 80% absorber-20% scintillating fibers calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); Bini, C., E-mail: cesare.bini@roma1.infn.i [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Via della Vasca Navale, 84 I-00146 Roma (Italy); Corradi, G.; Curceanu, C. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Via della Vasca Navale, 84 I-00146 Roma (Italy); INFN Sezione di Roma Tre, Via della Vasca Navale, 84 I-00146 Roma (Italy); Ferrari, A. [Institute of Safety Research and Institute of Radiation Physics, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden (Germany); Fiore, S. [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Gauzzi, P., E-mail: paolo.gauzzi@roma1.infn.i [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Giovannella, S.; Happacher, F. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); Iliescu, M. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); ' Horia Hulubei' National Institute of Physics and Nuclear Engineering, Str. Atomistilor no. 407, P.O. Box MG-6 Bucharest-Magurele (Romania); Luca, A.; Martini, M.; Miscetti, S. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy)

    2011-01-21

    The neutron detection efficiency of a sampling calorimeter made of 1 mm diameter scintillating fibers embedded in a lead/bismuth structure has been measured at the neutron beam of The Svedberg Laboratory at Uppsala. A significant enhancement of the detection efficiency with respect to a bulk organic scintillator detector with the same thickness is observed.

  5. CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Andreani, C.; D'Angelo, A.; Gorini, G.; Imberti, S.; Pietropaolo, A.; Rhodes, N. J.; Schooneveld, E. M.; Senesi, R.; Tardocchi, M.

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ( 25 meV) to epithermal ( 70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6Li glass, allowing us to measure F(y) up to the fourth 238U absorption energy (Er=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ω>1 eV) and low wavevector (q <10 Å-1) transfers.

  6. CdZnTe γ detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Andreani, C.; Pietropaolo, A.; Senesi, R.; D'Angelo, A.; Gorini, G.; Imberti, S.; Tardocchi, M.; Rhodes, N.J.; Schooneveld, E.M.

    2004-01-01

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal (∝25 meV) to epithermal (∝70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in 238 U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional 6 Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to 6 Li glass, allowing us to measure F(y) up to the fourth 238 U absorption energy (E r =66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy (ℎω>1 eV) and low wavevector (q -1 ) transfers. (orig.)

  7. CdZnTe {gamma} detector for deep inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Andreani, C.; Pietropaolo, A.; Senesi, R. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Tor Vergata (Italy); D' Angelo, A. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione, Roma II (Italy); Gorini, G.; Imberti, S.; Tardocchi, M. [Dipartimento di Fisica G. Occhialini, Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126, Milano (Italy); Istituto Nazionale per la Fisica della Materia, UdR, Milano-Bicocca (Italy); Rhodes, N.J.; Schooneveld, E.M. [Isis Facility, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, Oxfordshire (United Kingdom)

    2004-03-01

    In this paper it is shown that solid-state cadmium-zinc-telluride (CZT) is a promising photon detector for neutron spectroscopy in a wide energy interval, ranging from thermal ({proportional_to}25 meV) to epithermal ({proportional_to}70 eV) neutron energies. In the present study two CZT detectors were tested as part of the inverse-geometry neutron spectrometer VESUVIO operating at the ISIS pulsed neutron source. The response of the CZT detector to photon emission from radiative neutron capture in {sup 238}U was determined by biparametric measurements of neutron time of flight and photon energy. The scattering response function F(y) from a Pb sample has been derived using both CZT and conventional {sup 6}Li-glass scintillator detectors. The former showed both an improved signal to background ratio and higher efficiency as compared to {sup 6}Li glass, allowing us to measure F(y) up to the fourth {sup 238}U absorption energy (E{sub r}=66.02 eV). Due to the small size of CZT detectors, their use is envisaged in arrays, with high spatial resolution, for neutron-scattering studies at high energy ({Dirac_h}{omega}>1 eV) and low wavevector (q <10 A{sup -1}) transfers. (orig.)

  8. Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, R., E-mail: raspberry@lanl.gov; Cutler, T. E.; Danly, C. R.; Espy, M. A.; Goglio, J. H.; Hunter, J. F.; Madden, A. C.; Mayo, D. R.; Merrill, F. E.; Nelson, R. O.; Swift, A. L.; Wilde, C. H.; Zocco, T. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-11-15

    The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight. As a result, there has been increased effort to identify new image collection techniques that improve upon imaging resolution for these next generation neutron imaging systems, such as monolithic deuterated scintillators. This work details measurements performed at the Weapons Neutron Research Facility at Los Alamos National Laboratory that compares the radiographic abilities of the fiber scintillator with a monolithic scintillator, which may be featured in a future short line of sight neutron imaging systems.

  9. Monte Carlo calculation of the photo-fraction R(E) of NaI(Tl) scintillation spectrometer

    CERN Document Server

    Guo Chun Ying; Lin Yuan Ge

    2002-01-01

    The detecting principle of NaI(Tl) scintillation spectrometer is briefly analysed and the photo-fraction of the spectrometer to various point sources is calculated by using the MCNP code. Besides, comparison of the calculated results with experiment data available is made, and the reason why the calculated results are usually higher is also given

  10. Simulation and optimisation of a position sensitive scintillation detector with wavelength shifting fibers for thermal neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Herzkamp, Matthias; Engels, Ralf; Kemmerling, Guenter [ZEA-2, Forschungszentrum Juelich (Germany); Brueckel, Thomas [JCNS, Forschungszentrum Juelich (Germany); Stahl, Achim [III. Physikalisches Institut B, RWTH Aachen (Germany); Waasen, Stefan van [ZEA-2, Forschungszentrum Juelich (Germany); Faculty of Engineering, University of Duisburg-Essen (Germany)

    2015-07-01

    In neutron scattering experiments it is important to have position sensitive large scale detectors for thermal neutrons. A detector based on a neutron scintillator with wave length shifting fibers is a new kind of such a detector. We present the simulation of the detector based on the microscopic structure of the scintillation material of the mentioned detector. It consists of a converter and a scintillation powder bound in a matrix. The converter in our case is lithium fluoride with enriched lithium 6, to convert thermal neutrons into high energetic alpha and triton particles. The scintillation material is silver doped zinc sulfide. We show that pulse height spectra obtained by these scintillators can be be explained by the simple model of randomly distributed spheres of zinc sulfide and lithium fluoride. With this model, it is possible to optimise the mass ratio of zinc sulfide to lithium fluoride with respect to detection efficiency and/or energy deposition in zinc sulfide.

  11. Generation of organic scintillators response function for fast neutrons using the Monte Carlo method

    International Nuclear Information System (INIS)

    Mazzaro, A.C.

    1979-01-01

    A computer program (DALP) in Fortran-4-G language, has been developed using the Monte Carlo method to simulate the experimental techniques leading to the distribution of pulse heights due to monoenergetic neutrons reaching an organic scintillator. The calculation of the pulse height distribution has been done for two different systems: 1) Monoenergetic neutrons from a punctual source reaching the flat face of a cylindrical organic scintillator; 2) Environmental monoenergetic neutrons randomly reaching either the flat or curved face of the cylindrical organic scintillator. The computer program has been developed in order to be applied to the NE-213 liquid organic scintillator, but can be easily adapted to any other kind of organic scintillator. With this program one can determine the pulse height distribution for neutron energies ranging from 15 KeV to 10 MeV. (Author) [pt

  12. Thermal neutron detector and gamma-ray spectrometer utilizing a single material

    Science.gov (United States)

    Stowe, Ashley; Burger, Arnold; Lukosi, Eric

    2017-05-02

    A combined thermal neutron detector and gamma-ray spectrometer system, including: a detection medium including a lithium chalcopyrite crystal operable for detecting thermal neutrons in a semiconductor mode and gamma-rays in a scintillator mode; and a photodetector coupled to the detection medium also operable for detecting the gamma rays. Optionally, the detection medium includes a .sup.6LiInSe.sub.2 crystal. Optionally, the detection medium comprises a compound formed by the process of: melting a Group III element; adding a Group I element to the melted Group III element at a rate that allows the Group I and Group III elements to react thereby providing a single phase I-III compound; and adding a Group VI element to the single phase I-III compound and heating; wherein the Group I element includes lithium.

  13. γ-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Schooneveld, E.M.; Andreani, C.; Senesi, R.

    2009-01-01

    An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

  14. γ-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

    Science.gov (United States)

    Pietropaolo, A.; Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Schooneveld, E. M.; Andreani, C.; Senesi, R.

    2009-09-01

    An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

  15. {gamma}-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Pietropaolo, A. [CNISM Milano-Bicocca, Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: antonino.pietropaolo@mib.infn.it; Perelli Cippo, E. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Gorini, G. [CNISM Milano-Bicocca, Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Tardocchi, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Schooneveld, E.M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0QX OX11 (United Kingdom); Andreani, C.; Senesi, R. [Universia degli Studi di Roma Tor Vergata, Dipartimento di Fisica and NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), via della Ricerca Scientifica 1, 00133 Roma (Italy)

    2009-09-01

    An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

  16. A real-time neutron-gamma discriminator based on the support vector machine method for the time-of-flight neutron spectrometer

    Science.gov (United States)

    Wei, ZHANG; Tongyu, WU; Bowen, ZHENG; Shiping, LI; Yipo, ZHANG; Zejie, YIN

    2018-04-01

    A new neutron-gamma discriminator based on the support vector machine (SVM) method is proposed to improve the performance of the time-of-flight neutron spectrometer. The neutron detector is an EJ-299-33 plastic scintillator with pulse-shape discrimination (PSD) property. The SVM algorithm is implemented in field programmable gate array (FPGA) to carry out the real-time sifting of neutrons in neutron-gamma mixed radiation fields. This study compares the ability of the pulse gradient analysis method and the SVM method. The results show that this SVM discriminator can provide a better discrimination accuracy of 99.1%. The accuracy and performance of the SVM discriminator based on FPGA have been evaluated in the experiments. It can get a figure of merit of 1.30.

  17. Background characterization in a liquid scintillation spectrometer; Caracterizacion del fondo de un espectrometro de centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Barquero, L.; Los Arcos, J.M.; Jimenez de Mingo, A.

    1995-07-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0 - 20 KeV, 0 - 800 KeV and 0 - 2 MeV, for volume between 2 and 20 mi of three commercial scintillators, Hisafe II, Ultima-Gold and Instagel, and quenching degree in the interval equivalent to 50% - 3% tritium efficiency. This procedure was tested with standard samples of 3H, and led to average discrepancies less than 10% for activity {>=}0,6 Bq, against conventional methods for which the discrepancies are twice on average. (Author) 10 refs.

  18. Study on the energy response to neutrons for a new scintillating-fiber-array neutron detector

    CERN Document Server

    Zhang Qi; Wang Qun; Xie Zhong Shen

    2003-01-01

    The energy response of a new scintillating-fiber-array neutron detector to neutrons in the energy range 0.01 MeV<=E sub n<=14 MeV was modeled by combining a simplified Monte Carlo model and the MCNP 4b code. In order to test the model and get the absolute sensitivity of the detector to neutrons, one experiment was carried out for 2.5 and 14 MeV neutrons from T(p,n) sup 3 He and T(d,n) sup 4 He reactions at the Neutron Generator Laboratory at the Institute of Modern Physics, the Chinese Academy of Science. The absolute neutron fluence was obtained with a relative standard uncertainty 4.5% or 2.0% by monitoring the associated protons or sup 4 He particles, respectively. Another experiment was carried out for 0.5, 1.0, 1.5, 2.0, 2.5 MeV neutrons from T(p,n) sup 3 He reaction, and for 3.28, 3.50, 4.83, 5.74 MeV neutrons from D(d,n) sup 3 He reaction on the Model 5SDH-2 accelerator at China Institute of Atomic Energy. The absolute neutron fluence was obtained with a relative standard uncertainty 5.0% by usin...

  19. Calibration of LiBaF sub 3 Ce scintillator for fission spectrum neutrons

    CERN Document Server

    Reeder, P L

    2002-01-01

    The scintillator LiBaF sub 3 doped with small amounts of Ce sup + sup 3 has the ability to distinguish heavy charged particles (p, d, t, or alpha) from beta and/or gamma radiation based on the presence or absence of nanosecond components in the scintillation light output. Since the neutron capture reaction on sup 6 Li produces recoil alphas and tritons, this scintillator also discriminates between neutron induced events and beta or gamma interactions. An experimental technique using a time-tagged sup 2 sup 5 sup 2 Cf source has been used to measure the efficiency of this scintillator for neutron capture, the calibration of neutron capture pulse height, and the pulse height resolution--all as a function of incident neutron energy.

  20. Discrimination methods between neutron and gamma rays for boron loaded plastic scintillators

    CERN Document Server

    Normand, S; Haan, S; Louvel, M

    2002-01-01

    Boron loaded plastic scintillators exhibit interesting properties for neutron detection in nuclear waste management and especially in investigating the amount of fissile materials when enclosed in waste containers. Combining a high thermal neutron efficiency and a low mean neutron lifetime, they are suitable in neutron multiplicity counting. However, due to their high sensitivity to gamma rays, pulse shape discrimination methods need to be developed in order to optimize the passive neutron assay measurement. From the knowledge of their physical properties, it is possible to separate the three kinds of particles that have interacted in the boron loaded plastic scintillator (gamma, fast neutron and thermal neutron). For this purpose, we have developed and compared the two well known discrimination methods (zero crossing and charge comparison) applied for the first time to boron loaded plastic scintillator. The setup for the zero crossing discrimination method and the charge comparison methods is thoroughly expl...

  1. Detection of fast neutrons in a plastic scintillator using digital pulse processing to reject gammas

    International Nuclear Information System (INIS)

    Reeder, P.L.; Peurrung, A.J.; Hansen, R.R.; Stromswold, D.C.; Hensley, W.K.; Hubbard, C.W.

    1999-01-01

    We report on neutron-gamma discrimination in a plastic scintillator based on the time delay inherent in second and third chance neutron scattering. Because of the time delay (∼3 ns) between the first and second scattering of a neutron, calculations of gammas and neutrons in a plastic scintillator predict that a neutron signal should be significantly broader than a pulse from a gamma event. Experimentally, we have used a fast digital oscilloscope coupled to a computer to examine individual pulses from neutron or gamma induced signals in fast scintillators coupled to a fast PMT. Individual neutron-induced signals were consistent with the predictions of our model, but gamma pulses were broader than expected. We present various tests to understand this phenomenon and discuss a way to overcome this problem

  2. Neutron flux measurement with 6Li and 7Li dual glass scintillators by γ compensation method

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Shulan; Zhang Shuheng

    1996-01-01

    Based on the characteristics of 6 Li glass scintillator which is sensitive to both neutron and gamma rays, and 7 Li glass scintillator which is sensitive to gamma rays only, a new method of detecting weak neutron flux under interference of strong gamma radiation has been investigated by means of 6 Li- 7 Li pair glass scintillator gamma compensation method. The result of neutron flux measurement by above-mentioned method with an error of about 1% when the gamma ray interference is up to 18.7% has been obtained

  3. Neutron flux measurement with 6Li and 7Li dual glass scintillators by γ compensation method

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Shulan; Zhang Shuheng

    1998-01-01

    Based on the characteristics of 6 Li glass scintillator which is sensitive to both neutron and gamma rays, and 7 Li glass scintillator which is sensitive to gamma rays only, a new method of detecting weak neutron flux under interference of strong gamma radiation has been investigated by mans of 6 Li- 7 Li dual glass scintillator gamma compensation method. The result of neutron flux measurement by above-mentioned method with an error of about 1% when the gamma ray interference is up to 18.7% has been obtained

  4. Considerations in the design of an improved transportable neutron spectrometer

    CERN Document Server

    Williams, A M; Brushwood, J M; Beeley, P A

    2002-01-01

    The Transportable Neutron Spectrometer (TNS) has been used by the Ministry of Defence for over 15 years to characterise neutron fields in workplace environments and provide local correction factors for both area and personal dosimeters. In light of advances in neutron spectrometry, a programme to evaluate and improve TNS has been initiated. This paper describes TNS, presents its operation in known radioisotope fields and in a reactor environment. Deficiencies in the operation of the instrument are highlighted, together with proposals for updating the response functions and spectrum unfolding methodologies.

  5. Beam-transport optimization for cold-neutron spectrometer

    Directory of Open Access Journals (Sweden)

    Nakajima Kenji

    2015-01-01

    Full Text Available We report the design of the beam-transport system (especially the vertical geometry for a cold-neutron disk-chopper spectrometer AMATERAS at J-PARC. Based on the elliptical shape, which is one of the most effective geometries for a ballistic mirror, the design was optimized to obtain, at the sample position, a neutron beam with high flux without serious degrading in divergence and spacial homogeneity within the boundary conditions required from actual spectrometer construction. The optimum focal point was examined. An ideal elliptical shape was modified to reduce its height without serious loss of transmission. The final result was adapted to the construction requirements of AMATERAS. Although the ideas studied in this paper are considered for the AMATERAS case, they can be useful also to other spectrometers in similar situations.

  6. Determination of phosphorous in cannabis by neutron activation analysis - measurement of 32P Cerenkov radiation by liquid scintillaton spectrometer

    International Nuclear Information System (INIS)

    Shinogi, M.; Mori, I.

    1977-05-01

    Thermal neutron activaton analysis with measurement of 32 P Cerenkov radiation by liquid scintillation spectrometer was used to determine phosphorus in cannabis. After irradiation of the sample, wet ashing was carried out with conc. nitric acid and 70% perchloric acid. The solution in l M perchloric acid transferred to an inorganic ion-exchange column containing acid aluminium oxide and phosphorus was quantitatively eluted with 1M hydrofluoric acid. The 32 P radioactivity of each fraction of the eluate was counted with Cerenkov radiation by a liquid scintillation spectrometer from 2 to 7 weeks after the irradiation. The activity curve decayed with 32 P half-life. The isotope channel ratio technique was applied for the quench correction. The optimal experimental conditions for chemical separation of phosphorus and for measuring the 32 P Cerenkov radiation were also examined. (Author)

  7. Time recording unit for a neutron time of flight spectrometer

    International Nuclear Information System (INIS)

    Puranik, Praful; Ajit Kiran, S.; Chandak, R.M.; Poudel, S.K.; Mukhopadhyay, R.

    2011-01-01

    Here the architecture and design of Time Recording Unit for a Neutron Time of Flight Spectrometer have been described. The Spectrometer would have an array of 50 Nos. of one meter long linear Position Sensitive Detector (PSD) placed vertically around the sample at a distance of 2000 mm. The sample receives periodic pulsed neutron beam coming through a Fermi chopper. The time and zone of detection of a scattered neutron in a PSD gives information of its flight time and path length, which will be used to calculate its energy. A neutron event zone (position) and time detection module for each PSD provides a 2 bit position/zone code and an event timing pulse. The path length assigned to a neutron detected in a zone (Z1, Z2 etc) in the PSD is the mean path length seen by the neutrons detected in that zone of the PSD. A Time recording unit described here receives event zone code and timing pulse for all the 50 detectors, tags a proper time window code to it, before streaming it to computer for calculation of the energy distribution of neutrons scattered from the sample

  8. The measurement of the fluorescence response of plastic scintillator ST1422 to neutron

    International Nuclear Information System (INIS)

    Luo Xiaobing; Xia Yijun; Yang Zhihua; Zhang Chuanfei; Peng Taiping; Li Rurong; Zhang Jianhua

    2004-01-01

    By using the T(p,n) and D(d,n) reactions as neutron resources, the fluorescence response of ST1422 plastic scintillators (40 mm in diameter and 5 mm in thickness) was determined in he neutron energy range of 0.655-5 MeV. The experimental results show a nonlinear response of fluorescence with neutron energy. (authors)

  9. The characteristic calibration of the plastic scintillation detector for neutron diagnostic

    CERN Document Server

    Chen Hong Su

    2002-01-01

    The author presents the characteristic of the plastic scintillation detector used for pulse neutron diagnostic. The detection efficiency and sensitivity of the detector to DT neutron have been calibrated by the K-400 accelerator and by the pulse neutron tube, separately. The detection efficiency from the experiment is in agreement with that from calculation in the range of experimental errors

  10. Neutron spin echo spectrometer at JRR-3M

    International Nuclear Information System (INIS)

    Takeda, Takayoshi; Komura, Shigehiro; Seto, Hideki; Nagai, Michihiro; Kobayashi, Hideki; Yokoi, Eiji; Ebisawa, Tooru; Tasaki, Seiji.

    1993-01-01

    We have designed and have been constructing at C 2-2 cold neutron guide port of JRR-3M, JAERI, a neutron spin echo spectrometer (NSE) which is equipped with two optimized magnets for neutron spin precession, a position sensitive detector (PSD), a converging polarizer and a wide area analyzer. The dynamic range of scattering vector Q covers from 0.01 A -1 to 0.3 A -1 and that of energy E from 30neV to 0.1meV. This spectrometer makes it possible to study a mesoscopic spatial structure of the order of 1-100nm combined with a nanosecond temporal structure of the order of 0.1-100ns corresponding to dynamical behavior of large molecules such as polymer. A test experiment shows that the homogeneity condition of the precession magnet is loosened by means of PSD. (author)

  11. Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

    2015-07-01

    It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

  12. A plastic scintillator-based muon tomography system with an integrated muon spectrometer

    International Nuclear Information System (INIS)

    Anghel, V.; Armitage, J.; Baig, F.; Boniface, K.; Boudjemline, K.; Bueno, J.; Charles, E.; Drouin, P-L.; Erlandson, A.; Gallant, G.; Gazit, R.; Godin, D.; Golovko, V.V.; Howard, C.; Hydomako, R.

    2015-01-01

    A muon scattering tomography system which uses extruded plastic scintillator bars for muon tracking and a dedicated muon spectrometer that measures scattering through steel slabs has been constructed and successfully tested. The atmospheric muon detection efficiency is measured to be 97% per plane on average and the average intrinsic hit resolution is 2.5 mm. In addition to creating a variety of three-dimensional images of objects of interest, a quantitative study has been carried out to investigate the impact of including muon momentum measurements when attempting to detect high-density, high-Z material. As expected, the addition of momentum information improves the performance of the system. For a fixed data-taking time of 60 s and a fixed false positive fraction, the probability to detect a target increases when momentum information is used. This is the first demonstration of the use of muon momentum information from dedicated spectrometer measurements in muon scattering tomography

  13. Portable scintillation gamma-spectrometer for field measurement of radioactivity in extensive objects

    Directory of Open Access Journals (Sweden)

    O. A. Bezshyyko

    2011-12-01

    Full Text Available The portable scintillated gamma-spectrometer for field measurement of radioactivity in the volume objects was designed. The crystal CdWO4 that has weak dependence of light yield from temperature in combination with PMT was applied as the gamma-rays detector. The design of the device provides the possibility for measuring radioactivity of the extensive objects in 4-geometry without background measurements. In this case the value of the efficiency needed for specific activity calculation in close approximation depends only from crystal geometry and density of measuring object and may be set as the device parameter without efficiency calibration procedure during the operation. The spectrometer does not have an auxiliary radio-active source and connecting cables in the composition. The smartphone operated under Windows Mobile is used as the control module. Bluetooth connection provides data exchange between smartphone and measurement head.

  14. Portable scintillation gamma-spectrometer for field measurement of radioactivity in extensive objects

    International Nuclear Information System (INIS)

    Besshejko, O.A.; Vishnevskij, I.N.; Denisenko, R.V.; Malyuk, I.A.; Petrosyan, Eh.E.; Karpenko, S.A.; Prijmak, V.N.

    2011-01-01

    The portable scintillated gamma-spectrometer for field measurement of radioactivity in the volume objects was designed. The crystal CdWO 4 that has weak dependence of light yield from temperature in combination with PMT was applied as the gamma-rays detector. The design of the device provides the possibility for measuring radioactivity of the extensive objects in 4π-geometry without background measurements. In this case the value of the efficiency needed for specific activity calculation in close approximation depends only from crystal geometry and density of measuring object and may be set as the device parameter without efficiency calibration procedure during the operation. The spectrometer does not have an auxiliary radio-active source and connecting cables in the composition. The smartphone operated under Windows Mobile is used as the control module. Bluetooth connection provides data exchange between smartphone and measurement head.

  15. A plastic scintillator-based muon tomography system with an integrated muon spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Anghel, V. [Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Armitage, J. [Department of Physics, Room 3302 Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 (Canada); Baig, F.; Boniface, K. [Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Boudjemline, K. [Department of Physics, Room 3302 Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 (Canada); Bueno, J. [Advanced Applied Physics Solutions Inc., 4004 Wesbrook Mall, Vancouver, Canada V6T 2A3 (Canada); Charles, E. [Canada Border Services Agency, 79 Bentley Avenue, Ottawa, Canada K1A 0L8 (Canada); Drouin, P-L. [Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, Canada K1A 0Z4 (Canada); Erlandson, A., E-mail: Andrew.Erlandson@cnl.ca [Department of Physics, Room 3302 Herzberg Laboratories, Carleton University, 1125 Colonel By Drive, Ottawa, Canada K1S 5B6 (Canada); Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Gallant, G. [Canada Border Services Agency, 79 Bentley Avenue, Ottawa, Canada K1A 0L8 (Canada); Gazit, R. [Advanced Applied Physics Solutions Inc., 4004 Wesbrook Mall, Vancouver, Canada V6T 2A3 (Canada); Godin, D.; Golovko, V.V. [Canadian Nuclear Laboratories Ltd (former Atomic Energy of Canada Ltd), Chalk River Laboratories, Chalk River, Canada K0J 1P0 (Canada); Howard, C. [Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, Canada K1A 0Z4 (Canada); Hydomako, R. [Advanced Applied Physics Solutions Inc., 4004 Wesbrook Mall, Vancouver, Canada V6T 2A3 (Canada); Defence Research and Development Canada, 3701 Carling Avenue, Ottawa, Canada K1A 0Z4 (Canada); and others

    2015-10-21

    A muon scattering tomography system which uses extruded plastic scintillator bars for muon tracking and a dedicated muon spectrometer that measures scattering through steel slabs has been constructed and successfully tested. The atmospheric muon detection efficiency is measured to be 97% per plane on average and the average intrinsic hit resolution is 2.5 mm. In addition to creating a variety of three-dimensional images of objects of interest, a quantitative study has been carried out to investigate the impact of including muon momentum measurements when attempting to detect high-density, high-Z material. As expected, the addition of momentum information improves the performance of the system. For a fixed data-taking time of 60 s and a fixed false positive fraction, the probability to detect a target increases when momentum information is used. This is the first demonstration of the use of muon momentum information from dedicated spectrometer measurements in muon scattering tomography.

  16. A plastic scintillator-based muon tomography system with an integrated muon spectrometer

    Science.gov (United States)

    Anghel, V.; Armitage, J.; Baig, F.; Boniface, K.; Boudjemline, K.; Bueno, J.; Charles, E.; Drouin, P.-L.; Erlandson, A.; Gallant, G.; Gazit, R.; Godin, D.; Golovko, V. V.; Howard, C.; Hydomako, R.; Jewett, C.; Jonkmans, G.; Liu, Z.; Robichaud, A.; Stocki, T. J.; Thompson, M.; Waller, D.

    2015-10-01

    A muon scattering tomography system which uses extruded plastic scintillator bars for muon tracking and a dedicated muon spectrometer that measures scattering through steel slabs has been constructed and successfully tested. The atmospheric muon detection efficiency is measured to be 97% per plane on average and the average intrinsic hit resolution is 2.5 mm. In addition to creating a variety of three-dimensional images of objects of interest, a quantitative study has been carried out to investigate the impact of including muon momentum measurements when attempting to detect high-density, high-Z material. As expected, the addition of momentum information improves the performance of the system. For a fixed data-taking time of 60 s and a fixed false positive fraction, the probability to detect a target increases when momentum information is used. This is the first demonstration of the use of muon momentum information from dedicated spectrometer measurements in muon scattering tomography.

  17. Personnel neutron dose assessment upgrade: Volume 2, Field neutron spectrometer for health physics applications

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Reece, W.D.; Miller, S.D.

    1988-07-01

    Both the (ICRP) and the (NCPR) have recommended an increase in neutron quality factors and the adoption of effective dose equivalent methods. The series of reports entitled Personnel Neutron Dose Assessment Upgrade (PNL-6620) addresses these changes. Volume 1 in this series of reports (Personnel Neutron Dosimetry Assessment) provided guidance on the characteristics, use, and calibration of personnel neutron dosimeters in order to meet the new recommendations. This report, Volume 2: Field Neutron Spectrometer for Health Physics Applications describes the development of a portable field spectrometer which can be set up for use in a few minutes by a single person. The field spectrometer described herein represents a significant advance in improving the accuracy of neutron dose assessment. It permits an immediate analysis of the energy spectral distribution associated with the radiation from which neutron quality factor can be determined. It is now possible to depart from the use of maximum Q by determining and realistically applying a lower Q based on spectral data. The field spectrometer is made up of two modules: a detector module with built-in electronics and an analysis module with a IBM PC/reg sign/-compatible computer to control the data acquisition and analysis of data in the field. The unit is simple enough to allow the operator to perform spectral measurements with minimal training. The instrument is intended for use in steady-state radiation fields with neutrons energies covering the fission spectrum range. The prototype field spectrometer has been field tested in plutonium processing facilities, and has been proven to operate satisfactorily. The prototype field spectrometer uses a 3 He proportional counter to measure the neutron energy spectrum between 50 keV and 5 MeV and a tissue equivalent proportional counter (TEPC) to measure absorbed neutron dose

  18. Prismatic analyzer concept for neutron spectrometers

    DEFF Research Database (Denmark)

    Birk, Jonas O.; Marko, M.; Freeman, P.G.

    2014-01-01

    readily be combined with advanced focussing geometries and with multiplexing instrument designs. We present a combination of simulations and data showing three different energies simultaneously reflected from one analyser. Experiments were performed on a cold triple axis instrument and on a prototype...... inverse geometry Time-of-flight spectrometer installed at PSI, Switzerland, and shows excellent agreement with the predictions. Typical improvements will be 2.0 times finer resolution and a factor of 1.9 in flux gain compared to a focussing Rowland geometry, or of 3.3 times finer resolution and a factor...

  19. A wide-range direction neutron spectrometer

    International Nuclear Information System (INIS)

    Luszik-Bhadra, M.; D'Errico, F.; Hecker, O.; Matzke, M.

    2002-01-01

    A new device is presented which has been developed for measuring the energy and direction of distribution of neutron fluence in fields of broad energy spectra (thermal to 100 MeV) and with a high background of photon, electron and muon radiation. The device was tested in reference fields with different energy and direction distributions of neutron fluence. The direction-integrated fluence spectra agree fairly well with reference spectra. In all cases, the ambient and personal dose equivalent values calculated from measured direction-differential spectra are within 35% of the reference values. Independent measurements of the directional dose equivalent were performed with a directional dose equivalent monitor based on superheated drop detectors

  20. A Time of flight spectrometer for measurements of double differential neutron scattering cross sections; Montaje de un espectrometro por tiempo de vuelo para la medicion de secciones doble diferenciales de dispersion de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Padron, I; Dominguez, O; Sarria, P. Sandin, C. [Centro de Estudios Aplicados al Desarrollo Nuclear (CEADEN), La Habana (Cuba)

    1996-05-01

    The time -of-Flight neutron spectrometry technique by associated particle method was improved using a D-T neutron generator at Laboratory of Nuclear Analysis. This technique was implemented for double differential cross section measurements and supported by the IAEA Project CUB/01/005. An stilbene scintillation detector (dia=100 mm, length=50 mm) was used as principal neutron detector detector and was situated outside a hole in the concrete wall. This way the fligth path was extended and the scattered neutron cone accurate collimated throught the 2 m concrete wall. For the associated particle {alpha} detection a thin plastic NE-102 scint illator was used, as well as, two scintilation detectors and a long counter for the neutron flux monitoring. In this TOF neutron spectrometer (3.40 m flight path) a 1.7 nseg. temporal resolution was obtained.

  1. Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator

    Science.gov (United States)

    Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel. S.; Lee, Seung Wook

    2018-03-01

    We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

  2. An automatic control unit for A neutron diffraction crystal spectrometer

    International Nuclear Information System (INIS)

    Adib, M.; Abbas, Y.; Mostafa, M.; Hamouda, I.

    1982-01-01

    An automatic transistorized unit has been designed and constructed to control the operation of the double axis crystal spectrometer installed in front of one of the horizontal channels of the ET-RR-1 reactor. The function of the automatic unit is to store the diffracted neutrons at a certain angle with respect to the direction of the incident neutron beam in a selected channel of a 1024-multichannel analyzer for a certain preadjusted time period. AT the end of this time period the unit rotates the spectrometer's arm to another angle, selects the next channel of the MCA and provides the measurement of the diffracted neutron for the same time period. Such a sequence is repeated automatically over all angles required for the neutron diffraction pattern of the sample under investigation. As a result, the stored information at the MCA provides the neutron diffraction pattern as a function of channel number, where each channel corresponds to a certain scattering angle. The stored distribution at MCA can be obtained through the analyzer read out unit. The designed automatic unit has the possibility of providing the neutron diffraction pattern using a 6-digit scaler and a printer

  3. Automatic control unit for A neutron diffraction crystal spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Abbas, Y.; Mostafa, M.; Hamouda, I.

    1982-01-01

    An automatic transistorized unit has been designed and constructed to control the operation of the double axis crystal spectrometer installed in front of one of the horizontal channels of the ET-RR-1 reactor. The function of the automatic unit is to store the diffracted neutrons at a certain angle with respect to the direction of the incident neutron beam in a selected channel of a 1024-multichannel analyzer for a certain preadjusted time period. AT the end of this time period the unit rotates the spectrometer's arm to another angle, selects the next channel of the MCA and provides the measurement of the diffracted neutron for the same time period. Such a sequence is repeated automatically over all angles required for the neutron diffraction pattern of the sample under investigation. As a result, the stored information at the MCA provides the neutron diffraction pattern as a function of channel number, where each channel corresponds to a certain scattering angle. The stored distribution at MCA can be obtained through the analyzer read out unit. The designed automatic unit has the possibility of providing the neutron diffraction pattern using a 6-digit scaler and a printer.

  4. Comparison of Cadmium-Zinc-Telluride semiconductor and Yttrium-Aluminum-Perovskite scintillator as photon detectors for epithermal neutron spectroscopy

    International Nuclear Information System (INIS)

    Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Gorini, G.; Imberti, S.; Perelli-Cippo, E.; Senesi, R.; Rhodes, N.; Schooneveld, E.M.

    2006-01-01

    The range of applications of epithermal neutron scattering experiments has been recently extended by the development of the Resonance Detector. In a Resonance Detector, resonant neutron absorption in an analyzer foil results in prompt emission of X- and γ-rays which are detected by a photon counter. Several combinations of analyzer foils and photon detectors have been studied and tested over the years and best results have been obtained with the combination of a natural uranium and (i) Cadmium-Zinc-Telluride (CZT) semiconductor (ii) Yttrium-Aluminum-Perovskite (YAP) scintillators. Here we compare the performance of the CZT semiconductor and YAP scintillator as Resonance Detector units. Two Resonance Detector prototypes made of natural uranium foil viewed by CZT and YAP were tested on the VESUVIO spectrometer at the ISIS spallation neutron source. The results show that both YAP and CZT can be used to detect epithermal neutrons in the energy range from 1 up to 66 eV. It was found that the signal-to-background ratio of the measurement can significantly be improved by raising the lower level discrimination threshold on the γ energy to about 600 keV. The advantages/disadvantages of the choice of a Resonance Detector based on YAP or CZT are discussed together with some potential applications

  5. Design, construction, and calibration of a nonfocusing neutron spectrometer

    International Nuclear Information System (INIS)

    Storey, W.

    1974-12-01

    A fourteen-channel time-resolved neutron spectrometer with associated Faraday cup has been designed and constructed for use in the field. A neutron energy range of 9.5 to 15 MeV is covered. Both instruments detect protons elastically scattered from a thin hydrogenous foil in interaction with the neutron beam, with magnetic analysis of the protons by the spectrometer. The design requirements of small size and weight and 0.6 to 0.7 MeV resolution have been met. Following a description of the instrument and of its geometry, there is a detailed presentation of the design and construction of the instrument. The section on instrument performance is concerned with the comparison between predicted performance based upon computation, in which the magnet is of primary interest, and upon measured performance based upon a calibration experiment, which is given a general description in Appendix A. Software used mainly for signal prediction and unfolding, for both the neutron spectrometer and Faraday cup, is described

  6. Neutron guide shielding for the BIFROST spectrometer at ESS

    DEFF Research Database (Denmark)

    Mantulnikovs, K.; Bertelsen, M.; Cooper-Jensen, C.P.

    2016-01-01

    We report on the study of fast-neutron background for the BIFROST spectrometer at ESS. We investigate the effect of background radiation induced by the interaction of fast neutrons from the source with the material of the neutron guide and devise a reasonable fast, thermal/cold neutron shielding...... solution for the current guide geometry using McStas and MCNPX. We investigate the effectiveness of the steel shielding around the guide by running simulations with three different steel thicknesses. The same approach is used to study the efficiencies of the steel wall a flat cylinder pierced by the guide...... in the middle and the polyethylene layer. The final model presented here has a 3 cm thick steel shielding around the guide, 30 cm of polyethylene around the shielding, two 5 mm thick B4C layers and a steel wall at position Z = 38 m, being 1 m thick and 10 m in radius. The final model finally proves...

  7. Characterization of plastic scintillators for detection of radioactivity: Light yield, Time decay measurements and Neutron/γ Pulse Shape Discrimination

    International Nuclear Information System (INIS)

    Montbarbon, E.; Pansu, R.B.; Hamel, M.; Coulon, R.

    2015-07-01

    Since Helium-3 shortage, organic scintillators play a major role in neutron detection. CEA LIST decided to focus on plastic scintillators. By definition, a plastic scintillator is a radio-luminescent polymer; this means that it emits light after interaction with an ionizing radiation. A platform was developed to characterize lab-made prepared scintillators and to compare them with commercial scintillators. Three physicochemical criteria are determined with this unique platform. (authors)

  8. An active pixels spectrometers for neutronic fields metrology

    International Nuclear Information System (INIS)

    Taforeau, Julien

    2013-01-01

    The fundamental metrology is responsible for the sustainability of the measurement systems and handles to supply the reference standards. Concerning the metrology of ionizing radiations and, in particular the neutron metrology, detectors standards are used to characterize reference fields, in terms of energy and fluence. The dosimeters or particle detectors are calibrated on these reference fields. This thesis presents the development of a neutron spectrometer neutron candidate to the status of primary standard for the characterization of neutron fields in the range from 5 to 20 MeV. The spectrometer uses the recoil proton telescope as detection principle; the CMOS technology, through three sensor positions, is taking advantage to realize the tracking of protons. A Si(Li) detector handles the measure of the residual proton energy. The device simulations, realized under MCNPX, allow to estimate its performances and to validate the neutron energy reconstruction. An essential step of characterization of the telescope elements and in particular of CMOS sensors is also proposed to guarantee the validity of posterior experimental measurements. The tests realized as well in mono-energy fields as in radionuclide source show the very good performances of the system. The quantification of uncertainties indicates an energy estimation with 1.5 % accuracy and a resolution of less than 6 %. The fluence measurement is performed with an uncertainty about 4 to 6%. (author)

  9. Evaluations of the new LiF-scintillator and optional brightness enhancement films for neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Iikura, H., E-mail: Iikura.hiroshi@jaea.go.jp [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki (Japan); Tsutsui, N. [Chichibu Fuji Co., Ltd., Ogano, Chichibu, Saitama 368-0193 (Japan); Nakamura, T.; Katagiri, M.; Kureta, M. [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki (Japan); Kubo, J. [Nissan Motor Co., Ltd., Atsugi, Kanagawa 243-0126 (Japan); Matsubayashi, M. [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki (Japan)

    2011-09-21

    Japan Atomic Energy Agency has developed the neutron scintillator jointly with Chichibu Fuji Co., Ltd. In this study, we evaluated the new ZnS(Ag):Al/{sup 6}Li scintillator developed for neutron imaging. It was confirmed that the brightness increased by about double while maintaining equal performance for the spatial resolution as compared with a conventional scintillator. High frame-rate imaging using a high-speed video camera system and this new scintillator made it possible to image beyond 10 000 frames per second while still having enough brightness. This technique allowed us to obtain a high-frame-rate visualization of oil flow in a running car engine. Furthermore, we devised a technique to increase the light intensity of reception for a camera by adding brightness enhancement films on the output surface of the scintillator. It was confirmed that the spatial resolution degraded more than double, but the brightness increased by about three times.

  10. Characterisation of neutron beam and gamma spectrometer for PGAA

    International Nuclear Information System (INIS)

    Revay, Zs.; Molnar, G.L.

    2001-01-01

    In the second project year great efforts have been devoted in Budapest to the development of methods and procedures for neutron beam characterisation and spectrometer calibration. These are described here to provide recipes for other laboratories. Some illustrative results obtained on the former thermal guide, and partly on the new cold neutron guide are also given. Preliminary results from the benchmark experiments on flux monitors titanium standard and an unknown sample are also reported. New k o factors for elements of highest priority will be measured on the cold beam only in the near future. (author)

  11. The sensitivity calibration of the ultra-fast quench plastic scintillation detector for D-T neutrons

    International Nuclear Information System (INIS)

    Tang Changhuan; Yan Meiqiong; Xie Chaomei

    1998-01-01

    The authors introduce some characteristics of ultra-fast quench plastic scintillation detectors. When the detectors are composed of different scintillators, light guides and microchannel plate photomultiplier tube (MCP-PMT), their sensitivities to D-T neutrons are calibrated by a pulse neutron tube with a neutron pulse width about 10 ns

  12. Characterizing ICF Neutron Scintillation Diagnostics on the nTOF line at SUNY Geneseo

    Science.gov (United States)

    Lawson-Keister, Pat; Padawar-Curry, Jonah; Visca, Hannah; Fletcher, Kurt; Padalino, Stephen; Sangster, T. Craig; Regan, Sean

    2015-11-01

    Neutron scintillator diagnostics for ICF and HEDP can be characterized using the neutron time-of-flight (nTOF) line on Geneseo's 1.7 MV tandem Pelletron accelerator. Neutron signals can be differentiated from gamma signals by employing coincidence methods. A 1.8-MeV beam of deuterons incident on a deuterated polyethylene target produces neutrons via the 2H(d,n)3He reaction. Neutrons emerging at a lab angle of 88° have an energy of 2.96 MeV; the 3He ions associated with these neutrons are detected at a scattering angle of 43° using a surface barrier detector. The time of flight of the neutron can be measured by using the 3He detection as a ``start'' signal and the scintillation detection as a ``stop'' signal. This time of flight requirement is used to identify the 2.96-MeV neutron signals in the scintillator. To measure the light curve produced by these monoenergetic neutrons, two photomultiplier (PMT) tubes are attached to the scintillator. The full aperture PMT establishes the nTOF coincidence. The other PMT is fitted with a pinhole to collect single events. The time between the full aperture PMT signal and the arrival of the signal in the pinhole PMT is used to determine the light curve for the scintillator. This system will enable the neutron response of various scintillators to be compared. Supported in part by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  13. The scintillating fiber focal plane detector for the use of Kaos as a double arm spectrometer

    International Nuclear Information System (INIS)

    Ayerbe Gayoso, Carlos Antonio

    2012-01-01

    The upgrade of the Mainz Mikrotron (MAMI) electron accelerator facility in 2007 which raised the beam energy up to 1.5 GeV, gives the opportunity to study strangeness production channels through electromagnetic process. The Kaon Spectrometer (KAOS) managed by the A1 Collaboration, enables the efficient detection of the kaons associated with strangeness electroproduction. Used as a single arm spectrometer, it can be combined with the existing high-resolution spectrometers for exclusive measurements in the kinematic domain accessible to them. For studying hypernuclear production in the A Z(e,e'K + ) A Λ (Z-1) reaction, the detection of electrons at very forward angles is needed. Therefore, the use of KAOS as a double-arm spectrometer for detection of kaons and the electrons at the same time is mandatory. Thus, the electron arm should be provided with a new detector package, with high counting rate capability and high granularity for a good spatial resolution. To this end, a new state-of-the-art scintillating fiber hodoscope has been developed as an electron detector. The hodoscope is made of two planes with a total of 18432 scintillating double-clad fibers of 0.83 mm diameter. Each plane is formed by 72 modules. Each module is formed from a 60 slanted multi-layer bundle, where 4 fibers of a tilted column are connected to a common read out. The read-out is made with 32 channels of linear array multianode photomultipliers. Signal processing makes use of newly developed double-threshold discriminators. The discriminated signal is sent in parallel to dead-time free time-to-digital modules and to logic modules for triggering purposes. Two fiber modules were tested with a carbon beam at GSI, showing a time resolution of ∝220 ps (FWHM) and a position resolution of ∝270 μm (FWHM) with a detection efficiency ε>99%. The characterization of the spectrometer arm has been achieved through simulations calculating the transfer matrix of track parameters from the fiber

  14. The scintillating fiber focal plane detector for the use of Kaos as a double arm spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ayerbe Gayoso, Carlos Antonio

    2012-05-25

    The upgrade of the Mainz Mikrotron (MAMI) electron accelerator facility in 2007 which raised the beam energy up to 1.5 GeV, gives the opportunity to study strangeness production channels through electromagnetic process. The Kaon Spectrometer (KAOS) managed by the A1 Collaboration, enables the efficient detection of the kaons associated with strangeness electroproduction. Used as a single arm spectrometer, it can be combined with the existing high-resolution spectrometers for exclusive measurements in the kinematic domain accessible to them. For studying hypernuclear production in the {sup A}Z(e,e'K{sup +}){sup A}{sub {lambda}}(Z-1) reaction, the detection of electrons at very forward angles is needed. Therefore, the use of KAOS as a double-arm spectrometer for detection of kaons and the electrons at the same time is mandatory. Thus, the electron arm should be provided with a new detector package, with high counting rate capability and high granularity for a good spatial resolution. To this end, a new state-of-the-art scintillating fiber hodoscope has been developed as an electron detector. The hodoscope is made of two planes with a total of 18432 scintillating double-clad fibers of 0.83 mm diameter. Each plane is formed by 72 modules. Each module is formed from a 60 slanted multi-layer bundle, where 4 fibers of a tilted column are connected to a common read out. The read-out is made with 32 channels of linear array multianode photomultipliers. Signal processing makes use of newly developed double-threshold discriminators. The discriminated signal is sent in parallel to dead-time free time-to-digital modules and to logic modules for triggering purposes. Two fiber modules were tested with a carbon beam at GSI, showing a time resolution of {proportional_to}220 ps (FWHM) and a position resolution of {proportional_to}270 {mu}m (FWHM) with a detection efficiency {epsilon}>99%. The characterization of the spectrometer arm has been achieved through simulations

  15. Time coder for slow neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Grashilin, V.A.; Ofengenden, R.G.

    1988-01-01

    Time coder for slow neutron time-of-flight spectrometer is described. The time coder is of modular structure, is performed in the CAMAC standard and operates on line with DVK-2 computer. The main coder units include supporting generator, timers, time-to-digital converter, memory unit and crate controller. Method for measuring background symmetrically to the effect is proposed for a more correct background accounting. 4 refs.; 1 fig

  16. A PCI time digitizer for the new JET time-of-flight neutron spectrometer

    International Nuclear Information System (INIS)

    Sousa, J.; Batista, A.J.N.; Combo, A.; Pereira, R.; Cruz, N.; Carvalho, P.; Varandas, C.A.F.; Conroy, S.; Ericsson, G.; Kaellne, J.

    2004-01-01

    A PCI time digitizer module with eight independent time-to-digital converter (TDC) channels is being developed for the new time-of-flight spectrometer designed for optimized rate (TOFOR) which diagnoses deuterium plasmas of the EFDA-JET tokamak. The module shall measure with high accuracy the flight-times of 2.5 MeV neutrons in the 100 ns range as given by two groups of scintillation detectors operating at average event rates from the expected 500 kHz up to 5 MHz. The module stores up to 64 million hit-times with a resolution of 0.4 ns and incorporates a digital signal processor and a system-on-chip device which performs the data transfer, the device control/monitoring and may perform statistical, data reduction or control algorithms in real-time

  17. Neutron Detection with a Cryogenic Spectrometer

    CERN Document Server

    Bell, Z W; Cristy, S S; Lamberti, V E

    2003-01-01

    Cryogenic calorimeters are used for x-ray detection because of their exquisite energy resolution and have found application in x-ray astronomy, and the search for dark matter. These devices operate by detecting the heat pulse produced by ionization in an absorber cooled to temperatures below 1 K. Such temperatures are needed to lower the absorber's heat capacity to the point that the deposition of even a few eV results in a measurable temperature excursion. Typical absorbers for dark matter measurements are massive Si or Ge crystals, and, with Ge, have achieved a resolution of 650 eV at 10 keV. Chow, et al., report the measurement of the 60 keV emission from sup 2 sup 4 sup 1 Am with 230 eV resolution using a superconducting tin absorber. Cunningham, et al., also using a superconducting tin absorber, have recently reported a four-fold improvement over Chow. With such results being reported from the x- and gamma-ray world it is natural to examine the possibilities for cryogenic neutron spectroscopy. Such a det...

  18. Methyl salicylate as a medium for radioassay of 36Cl using a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Wiebe, L.I.; Ediss, C.

    1976-01-01

    Methyl salicylate (MS), a high refractive index liquid with wave-shifting properties, has been used as a Cherenkov radiation generating medium for the radioassay of 36 Cl by liquid scintillation (LS) spectrometer. Comparative experiments, using both a standard toluene-based LS fluor and toluene alone, for the measurement of 36 Cl were undertaken. The methyl salicylate medium was found to perform at an intermediate counting efficiency, near that for the LS fluor. In the presence of moderate amounts of nitromethane, the MS was less susceptible to chemical quenching effects than either the fluor or toluene. Counting efficiencies for 36 Cl in MS, toluene and toluene fluor respectively were 82.4, 28.4 and 100.3 percent with a Picker Liquimat 220 LS spectrometer, and 91.6, 54.9 and 100.0 percent with a Searle Mark III LS spectrometer. The addition of nitromethane (11.3 percent of final volume) reduced these efficiencies to 50.5, 10.0 and 15.4 percent, and to 58.8, 12.4 and 19.0 percent, respectively. The data are discussed in relation to observed changes in the pulse height spectra. Chemical quench correction by ESCR and by SCR methods is reported

  19. Upgrade of the compact neutron spectrometer for high flux environments

    Science.gov (United States)

    Osipenko, M.; Bellucci, A.; Ceriale, V.; Corsini, D.; Gariano, G.; Gatti, F.; Girolami, M.; Minutoli, S.; Panza, F.; Pillon, M.; Ripani, M.; Trucchi, D. M.

    2018-03-01

    In this paper new version of the 6Li-based neutron spectrometer for high flux environments is described. The new spectrometer was built with commercial single crystal Chemical Vapour Deposition diamonds of electronic grade. These crystals feature better charge collection as well as higher radiation hardness. New metal contacts approaching ohmic conditions were deposited on the diamonds suppressing build-up of space charge observed in the previous prototypes. New passive preamplification of the signal at detector side was implemented to improve its resolution. This preamplification is based on the RF transformer not sensitive to high neutron flux. The compact mechanical design allowed to reduce detector size to a tube of 1 cm diameter and 13 cm long. The spectrometer was tested in the thermal column of TRIGA reactor and at the DD neutron generator. The test results indicate an energy resolution of 300 keV (FWHM), reduced to 72 keV (RMS) excluding energy loss, and coincidence timing resolution of 160 ps (FWHM). The measured data are in agreement with Geant4 simulations except for larger energy loss tail presumably related to imperfections of metal contacts and glue expansion.

  20. A proton-recoil neutron spectrometer for time-dependent ion temperatures on the National Ignition Facility

    International Nuclear Information System (INIS)

    Murphy, T.J.

    1995-01-01

    Ion temperatures from inertial confinement fusion targets are usually determined by measuring the Doppler broadening of the neutron spectrum using the time-of-flight method. Measurement systems are generally designed so that the contribution of the duration of neutron production (∼100 ps) to the width of the neutron signal is negligible. This precludes the possibility of time-dependent ion temperature. If, however, one could measure the neutron energy and arrival time at a detector independently, then time-dependent neutron spectra could be obtained, and ion temperature information deduced. A concept utilizing a proton-recoil neutron spectrometer has been developed in which recoil protons from a small plastic foil are measured. From the energy, arrival time, and recoil angle of the recoil proton, the birth time and energy of the incident neutron can be deduced. The sensitivity of the system is low, but the higher anticipated neutron yields from the proposed National Ignition Facility may make the technique feasible. Large scintillator arrays currently in use on the Nova facility for neutron spectral measurements consist of ∼1,000 channels and detect between 50 and 500 counts for typical time-integrated data. Time-dependent results would then require about an order of magnitude larger system. Key issues for making this system feasible will be keeping the cost per channel low while allowing adequately time (∼ 50 ps), energy (20 keV), and angular resolution (2 mrad) for each of the proton detectors

  1. Calculation of efficiency of high-energy neutron detection by plastic scintillators

    International Nuclear Information System (INIS)

    Telegin, Yu.N.

    1977-01-01

    A computer was used to calculate neutron (5-30O MeV) registration effeciencies with plastic scintillators 2,5,10, 20,30,40 and 50 cm thick. The results are shown in the form of tables. The contributions to efficiency of various processes have been analysed. The calculation results may be used in planning experiments with neutron counters

  2. Time dispersion in large plastic scintillation neutron detector [Paper No.:B3

    International Nuclear Information System (INIS)

    De, A.; Dasgupta, S.S.; Sen, D.

    1993-01-01

    Time dispersion seen by photomultiplier (PM) tube in large plastic scintillation neutron detector and the light collection mechanism by the same have been computed showing that this time dispersion (TD) seen by the PM tube does not necessarily increase with increasing incident neutron energy in contrast to the usual finding that TD increases with increasing energy. (author). 8 refs., 4 figs

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-21

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

  5. Measurement and simulation of neutron detection efficiency in lead-scintillating fiber calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati, INFN (Italy); Bini, C. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Roma (Italy); Curceanu, C. [Laboratori Nazionali di Frascati, INFN (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Ferrari, A. [Fondazione CNAO, Milano (Italy); Fiore, S.; Gauzzi, P. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Giovannella, S., E-mail: simona.giovannella@lnf.infn.i [Laboratori Nazionali di Frascati, INFN (Italy); Happacher, F. [Laboratori Nazionali di Frascati, INFN (Italy); Iliescu, M. [Laboratori Nazionali di Frascati, INFN (Italy); IFIN-HH, Bucharest (Romania); Martini, M. [Laboratori Nazionali di Frascati, INFN (Italy); Dipartimento di Energetica dell' Universita ' La Sapienza' , Roma (Italy); Miscetti, S. [Laboratori Nazionali di Frascati, INFN (Italy); Nguyen, F. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Passeri, A. [INFN Sezione di Roma Tre, Roma (Italy); Prokofiev, A. [Svedberg Laboratory, Uppsala University (Sweden); Sciascia, B. [Laboratori Nazionali di Frascati, INFN (Italy)

    2009-12-15

    The overall detection efficiency to neutrons of a small prototype of the KLOE lead-scintillating fiber calorimeter has been measured at the neutron beam facility of The Svedberg Laboratory, TSL, Uppsala, in the kinetic energy range [5-175] MeV. The measurement of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 30% to 50%. This value largely exceeds the estimated 8-15% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beam line has been performed with the FLUKA Monte Carlo code. First data-MC comparisons are encouraging and allow to disentangle a neutron halo component in the beam.

  6. Measurement and simulation of neutron detection efficiency in lead-scintillating fiber calorimeters

    International Nuclear Information System (INIS)

    Anelli, M.; Bertolucci, S.; Bini, C.; Branchini, P.; Curceanu, C.; De Zorzi, G.; Di Domenico, A.; Di Micco, B.; Ferrari, A.; Fiore, S.; Gauzzi, P.; Giovannella, S.; Happacher, F.; Iliescu, M.; Martini, M.; Miscetti, S.; Nguyen, F.; Passeri, A.; Prokofiev, A.; Sciascia, B.

    2009-01-01

    The overall detection efficiency to neutrons of a small prototype of the KLOE lead-scintillating fiber calorimeter has been measured at the neutron beam facility of The Svedberg Laboratory, TSL, Uppsala, in the kinetic energy range [5-175] MeV. The measurement of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 30% to 50%. This value largely exceeds the estimated 8-15% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beam line has been performed with the FLUKA Monte Carlo code. First data-MC comparisons are encouraging and allow to disentangle a neutron halo component in the beam.

  7. Measurement and simulation of the neutron detection efficiency with a Pb-scintillating fiber calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Anelli, M; Bertolucci, S; Curceanu, C; Giovannella, S; Happacher, F; Iliescu, M; Martini, M; Miscetti, S [Laboratori Nazionali di Frascati, INFN (Italy); Battistoni, G [Sezione INFN di Milano (Italy); Bini, C; Zorzi, G De; Domenico, Adi; Gauzzi, P [Ubiversita degli Studi ' La Sapienza' e Sezine INFN di Roma (Italy); Branchini, P; Micco, B Di; Ngugen, F; Paseri, A [Universita degli di Studi ' Roma Tre' e Sezione INFN di Roma Tre (Italy); Ferrari, A [Fondazione CNAO, Milano (Italy); Prokfiev, A [Svedberg Laboratory, Uppsala University (Sweden); Fiore, S, E-mail: matteo.martino@inf.infn.i

    2009-04-01

    We have measured the overall detection efficiency of a small prototype of the KLOE PB-scintillation fiber calorimeter to neutrons with kinetic energy range [5,175] MeV. The measurement has been done in a dedicated test beam in the neutron beam facility of the Svedberg Laboratory, TSL Uppsala. The measurements of the neutron detection efficiency of a NE110 scintillator provided a reference calibration. At the lowest trigger threshold, the overall calorimeter efficiency ranges from 28% to 33%. This value largely exceeds the estimated {approx}8% expected if the response were proportional only to the scintillator equivalent thickness. A detailed simulation of the calorimeter and of the TSL beam line has been performed with the FLUKA Monte Carlo code. The simulated response of the detector to neutrons is presented together with the first data to Monte Carlo comparison. The results show an overall neutron efficiency of about 35%. The reasons for such an efficiency enhancement, in comparison with the typical scintillator-based neutron counters, are explained, opening the road to a novel neutron detector.

  8. A capture-gated neutron calorimeter using plastic scintillators and 3He drift tubes

    International Nuclear Information System (INIS)

    Wang, Zhehui; Morris, Christopher L.; Spaulding, Randy J.; Bacon, Jeffrey D.; Borozdin, Konstantin N.; Chung, Kiwhan; Clark, Deborah J.; Green, Jesse A.; Greene, Steven J.; Hogan, Gary E.; Jason, Andrew; Lisowski, Paul W.; Makela, Mark F.; Mariam, Fessaha G.; Miyadera, Haruo; Murray, Matthew M.; Saunders, Alexander; Wysocki, Frederick J.; Gray, Frederick E.

    2010-01-01

    A segmented neutron calorimeter using nine 4-inch x 4-inch x 48-inch plastic scintillators and sixteen 2-inch-diameter 48-inch-long 200-mbar- 3 He drift tubes is described. The correlated scintillator and neutron-capture events provide a means for n/γ discrimination, critical to the neutron calorimetry when the γ background is substantial and the γ signals are comparable in amplitude to the neutron signals. A single-cell prototype was constructed and tested. It can distinguish between a 17 N source and a 252 Cf source when the γ and the thermal neutron background are sufficiently small. The design and construction of the nine-cell segmented detector assembly follow the same principle. By recording the signals from individual scintillators, additional γ-subtraction schemes, such as through the time-of-flight between two scintillators, may also be used. The variations of the light outputs from different parts of a scintillator bar are less than 10%.

  9. SCALP: Scintillating ionization chamber for ALPha particle production in neutron induced reactions

    Science.gov (United States)

    Galhaut, B.; Durand, D.; Lecolley, F. R.; Ledoux, X.; Lehaut, G.; Manduci, L.; Mary, P.

    2017-09-01

    The SCALP collaboration has the ambition to build a scintillating ionization chamber in order to study and measure the cross section of the α-particle production in neutron induced reactions. More specifically on 16O and 19F targets. Using the deposited energy (ionization) and the time of flight measurement (scintillation) with a great accuracy, all the nuclear reaction taking part on this project will be identify.

  10. Fission signal detection using helium-4 gas fast neutron scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, J. M., E-mail: lewisj@ufl.edu; Kelley, R. P.; Jordan, K. A. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611 (United States); Murer, D. [Arktis Radiation Detectors Ltd., 8045 Zurich (Switzerland)

    2014-07-07

    We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure {sup 4}He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the {sup 4}He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

  11. Plastic scintillator with effective pulse shape discrimination for neutron and gamma detection

    Science.gov (United States)

    Zaitseva, Natalia P.; Carman, M Leslie; Cherepy, Nerine; Glenn, Andrew M.; Hamel, Sebastien; Payne, Stephen A.; Rupert, Benjamin L.

    2016-04-12

    In one embodiment, a scintillator material includes a polymer matrix; and a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 5 wt % or more; wherein the scintillator material exhibits an optical response signature for neutrons that is different than an optical response signature for gamma rays. In another embodiment, a scintillator material includes a polymer matrix; and a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount greater than 10 wt %.

  12. Highly efficient solid-state neutron scintillators based on hybrid sol-gel nanocomposite materials

    International Nuclear Information System (INIS)

    Kesanli, Banu; Hong, Kunlun; Meyer, Kent; Im, Hee-Jung; Dai, Sheng

    2006-01-01

    This research highlights opportunities in the formulation of neutron scintillators that not only have high scintillation efficiencies but also can be readily cast into two-dimensional detectors. Series of transparent, crack-free monoliths were prepared from hybrid polystyrene-silica nanocomposites in the presence of arene-containing alkoxide precursor through room temperature sol-gel processing. The monoliths also contain lithium-6 salicylate as a target material for neutron-capture reactions and amphiphilic scintillator solution as a fluorescent sensitizer. Polystyrene was functionalized by trimethoxysilyl group in order to enable the covalent incorporation of aromatic functional groups into the inorganic sol-gel matrices for minimizing macroscopic phase segregation and facilitating lithium-6 doping in the sol-gel samples. Neutron and alpha responses of these hybrid polystyrene-silica monoliths were explored

  13. Development of inelastic neutron spectrometer (DC-TOF) and utilization

    International Nuclear Information System (INIS)

    Park, Je Geun; So, J. Y.; Moon, M. K.; Choi, Y. H.; Cho, S. J.; Lee, C. H.; Nam, U. W.; Kim, H. Y.; Kim, H. J.

    2010-08-01

    DC-TOF is an inelastic neutron spectrometer with potentially very wide applications to areas such as physics, chemistry, biology, and material engineering. And it is the most technically challenging and advanced instrument by using high speed choppers rotating up to 20,000 RPM and wide detector of steradian producing data in the order of a few hundred Mbyte. Through this project, we have successfully developed DC-TOF at KAERI with the development of the following key technologies : - Detector Electronics - Data acquisition software - Data reduction software. We believe that DC-TOF will become a workhorse instrument for the wide community of sciences in Korea

  14. Modifications of micro-pulling-down method for the growth of selected Li-containing crystals for neutron scintillator and VUV scintillation crystals

    Science.gov (United States)

    Pejchal, J.; Fujimoto, Y.; Chani, V.; Yanagida, T.; Yokota, Y.; Yoshikawa, A.; Nikl, M.; Beitlerova, A.

    2012-12-01

    To develop new and efficient neutron scintillator, Ti-doped LiAlO2 single crystal was grown by micro-pulling-down method. The X-ray excited radioluminescence spectra and neutron light yield were measured. Positive effect of Mg codoping on the overall scintillation efficiency was found. The BaLu2F8 single crystal was grown by micro-pulling-down method using low temperature gradient at growth interface and applying quenching immediately after growth process.

  15. Design, building and evaluation of a neutron detection device based on boron loaded plastic scintillator

    International Nuclear Information System (INIS)

    Normand, St.

    2001-10-01

    This work focuses on the study, the characterization and the fabrication of Boron-loaded plastic scintillators. Their use in thermal and fast neutron detection devices is also investigated. Fabrication process, especially boron doping, is explained in the first part of this work. Several FTIR, UV-visible and NMR analysis methods were used in order to characterize the material and to check its structure and stoichiometry. Experiences were done using alpha particles and proton beams to measure the scintillation characteristics. Light emission could therefore be completely determined by the Birks semi-empirical relation. In the second part, the whole detector simulation is undergone: interaction between material and radiation, light generation, paths and signal generation. Neutron simulation by MCNP (Monte Carlo N-Particles) is coupled to a light generation and propagation code developed especially during this work. These simulation tools allow us to optimize the detector geometry for neutron detection and to determine the geometry influence to the photon collection efficiency. Neutron detection efficiency and mean lifetime in this scintillator are also simulated. The close fit obtained between experimental measurements and simulations demonstrate the reliability of the method used. The third part deals with the discrimination methods between neutron and gamma, such as analog (zero crossing) and digital (charge comparison) ones. Their performances were explained and compared. The last part of this work reports on few applications where neutron detection is essential and can be improved with the use of boron loaded plastic scintillators. In particular, the cases of doped scintillation fibers, neutron spectrometry devices and more over neutron multiplicity counting devices are presented. (author)

  16. Determination of the Jet Neutron Rate and Fusion Power using the Magnetic Proton Recoil Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoestrand, Henrik

    2003-01-01

    In this thesis a new independent method has been developed to enable precise measurements of neutron yields and rates from fusion plasmas and thereby determining the fusion power and fusion energy. The new method, together with the associated diagnostics, can provide information of great importance to present and future high fusion yield experiments, such as the Joint European Torus (JET) tokamak and the International Thermonuclear Experiment Reactor (ITER). The method has been applied to data from high fusion rate experiments from the tritium campaign at JET. By using the count-rate from the Magnetic Proton Recoil (MPR) neutron spectrometer the number of neutrons in the spectrometer's line of sight has been calculated. To be able to do this, all relevant factors between the plasma and the instrument have been evaluated. The number of neutrons in the MPR line of sight has been related to the total number of produced neutrons in the plasma by using information on the neutron emission profile. The achieved results have been compared with other JET neutron diagnostic data and the agreement is shown to be very good.

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

    International Nuclear Information System (INIS)

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

    2013-06-01

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

  18. Fan analyzer of neutron beam polarization on REMUR spectrometer at IBR-2 pulsed reactor

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ul'yanov, V.A.; Pusenkov, V.M.; Kozhevnikov, S.V.; Jernenkov, K.N.; Pleshanov, N.K.; Peskov, B.G.; Petrenko, A.V.; Proglyado, V.V.; Syromyatnikov, V.G.; Schebetov, A.F.

    2006-01-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation in the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multiplayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 A. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (fan-like polarization analyzer) with a solid angle of neutron detection of 2.2x10 -4 rad. This article describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of its tests on a polarized neutron beam

  19. Neutron-gamma discrimination based on pulse shape discrimination in a Ce:LiCaAlF{sub 6} scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Atsushi, E-mail: a-yamazaki@nucl.nagoya-u.ac.jp [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University (Japan); Watanabe, Kenichi; Uritani, Akira [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University (Japan); Iguchi, Tetsuo [Department of Quantum Engineering, Graduate School of Engineering, Nagoya University (Japan); Kawaguchi, Noriaki [Tokuyama Corporation (Japan); Yanagida, Takayuki; Fujimoto, Yutaka; Yokota, Yuui; Kamada, Kei [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University (Japan); Fukuda, Kentaro; Suyama, Toshihisa [Tokuyama Corporation (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University (Japan)

    2011-10-01

    We demonstrate neutron-gamma discrimination based on a pulse shape discrimination method in a Ce:LiCAF scintillator. We have tried neutron-gamma discrimination using a difference in the pulse shape or the decay time of the scintillation light pulse. The decay time is converted into the rise time through an integrating circuit. A {sup 252}Cf enclosed in a polyethylene container is used as the source of thermal neutrons and prompt gamma-rays. Obvious separation of neutron and gamma-ray events is achieved using the information of the rise time of the scintillation light pulse. In the separated neutron spectrum, the gamma-ray events are effectively suppressed with little loss of neutron events. The pulse shape discrimination is confirmed to be useful to detect neutrons with the Ce:LiCAF scintillator under an intense high-energy gamma-ray condition.

  20. Fast neutron and gamma-ray spectra measurements with a NE-213 spectrometer in the FNG Copper Benchmark Experiment

    International Nuclear Information System (INIS)

    Klix, Axel; Angelone, Maurizio; Fischer, Ulrich; Pillon, Mario

    2016-01-01

    Highlights: • Fast neutron and gamma-ray spectra were measured in a copper assembly irradiated with DT neutrons. • The results were compared with MCNP calculations. • Primary aim was to provide experimental data for checking and validation of nuclear data evaluations of copper. - Abstract: A neutronics benchmark experiment on a pure Copper assembly was performed at the Frascati Neutron Generator. The work aimed at testing of recent nuclear data libraries. This paper focuses on the measurement of fast neutron and gamma-ray flux spectra in the Copper assembly under DT neutron irradiation in two selected positions with a spectrometer based on the organic liquid scintillator NE-213. The measurement results were compared with Monte Carlo radiation transport calculations using MCNP and nuclear data from the JEFF-3.1.1 library. Calculations have been done with Cu data from JEFF-3.1.1, JEFF-3.2, FENDL-3 and ENDF/B-7.0. Discrepancies appear in the intermediate neutron energy range between experiment and calculation. Large discrepancies were observed in the gamma-ray spectra calculated with JEFF-3.2.

  1. Fast neutron and gamma-ray spectra measurements with a NE-213 spectrometer in the FNG Copper Benchmark Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Klix, Axel, E-mail: axel.klix@kit.edu [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Angelone, Maurizio [ENEA Dipartimento Fusione e Tecnologie per la Sicurezza Nucleare, C.R. Frascati, via E. Fermi 45, 00044 Frascati (Italy); Fischer, Ulrich [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pillon, Mario [ENEA Dipartimento Fusione e Tecnologie per la Sicurezza Nucleare, C.R. Frascati, via E. Fermi 45, 00044 Frascati (Italy)

    2016-11-01

    Highlights: • Fast neutron and gamma-ray spectra were measured in a copper assembly irradiated with DT neutrons. • The results were compared with MCNP calculations. • Primary aim was to provide experimental data for checking and validation of nuclear data evaluations of copper. - Abstract: A neutronics benchmark experiment on a pure Copper assembly was performed at the Frascati Neutron Generator. The work aimed at testing of recent nuclear data libraries. This paper focuses on the measurement of fast neutron and gamma-ray flux spectra in the Copper assembly under DT neutron irradiation in two selected positions with a spectrometer based on the organic liquid scintillator NE-213. The measurement results were compared with Monte Carlo radiation transport calculations using MCNP and nuclear data from the JEFF-3.1.1 library. Calculations have been done with Cu data from JEFF-3.1.1, JEFF-3.2, FENDL-3 and ENDF/B-7.0. Discrepancies appear in the intermediate neutron energy range between experiment and calculation. Large discrepancies were observed in the gamma-ray spectra calculated with JEFF-3.2.

  2. Scintillators

    International Nuclear Information System (INIS)

    Cusano, D.A.; Holub, F.F.; Prochazka, S.

    1979-01-01

    Scintillator bodies comprising phosphor materials and having high optical translucency with low light absorption, and methods of making the scintillator bodies, are described. Fabrication methods include (a) a hot-pressing process, (b) cold-pressing followed by sintering, (c) controlled cooling from a melt, and (d) hot-forging. The scintillator bodies that result are easily machined to desired shapes and sizes. Suitable phosphors include BaFCl:Eu, LaOBr:Tb, CsI:Tl, CaWO 4 and CdWO 4 . (U.K.)

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

    International Nuclear Information System (INIS)

    Nakhostin, M

    2013-01-01

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

  4. 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.

  5. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

    2016-08-21

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  6. Sensitive and transportable gadolinium-core plastic scintillator sphere for neutron detection and counting

    International Nuclear Information System (INIS)

    Dumazert, Jonathan; Coulon, Romain; Carrel, Frédérick; Corre, Gwenolé; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-01-01

    Neutron detection forms a critical branch of nuclear-related issues, currently driven by the search for competitive alternative technologies to neutron counters based on the helium-3 isotope. The deployment of plastic scintillators shows a high potential for efficient detectors, safer and more reliable than liquids, more easily scalable and cost-effective than inorganic. In the meantime, natural gadolinium, through its 155 and mostly 157 isotopes, presents an exceptionally high interaction probability with thermal neutrons. This paper introduces a dual system including a metal gadolinium core inserted at the center of a high-scale plastic scintillator sphere. Incident fast neutrons are thermalized by the scintillator shell and then may be captured with a significant probability by gadolinium 155 and 157 nuclei in the core. The deposition of a sufficient fraction of the capture high-energy prompt gamma signature inside the scintillator shell will then allow discrimination from background radiations by energy threshold, and therefore neutron detection. The scaling of the system with the Monte Carlo MCNPX2.7 code was carried out according to a tradeoff between the moderation of incident fast neutrons and the probability of slow neutron capture by a moderate-cost metal gadolinium core. Based on the parameters extracted from simulation, a first laboratory prototype for the assessment of the detection method principle has been synthetized. The robustness and sensitivity of the neutron detection principle are then assessed by counting measurement experiments. Experimental results confirm the potential for a stable, highly sensitive, transportable and cost-efficient neutron detector and orientate future investigation toward promising axes.

  7. Novel methods for measuring afterglow in developmental scintillators for X-ray and neutron detection

    Science.gov (United States)

    Bartle, C. M.; Edgar, A.; Dixie, L.; Varoy, C.; Piltz, R.; Buchanan, S.; Rutherford, K.

    2011-09-01

    In this paper we discuss two novel methods of measuring afterglow in scintillators. One method is designed for X-ray detection and the other for neutron detection applications. In the first method a commercial fan-beam scanner of basic design similar to those seen at airports is used to deliver a typically 12 ms long X-ray pulse to a scintillator by passing the test equipment through the scanner on the conveyor belt. In the second method the thermal neutron beam from a research reactor is incident on the scintillator. The beam is cut-off in about 1 ms using a 10B impregnated aluminum pneumatic shutter, and the afterglow is recorded on a dual range storage oscilloscope to capture both the steady state intensity and the weak decay. We describe these measurement methods and the results obtained for a range of developmental ceramic and glass scintillators, as well as some standard scintillators such as NaI(Tl), LiI(Eu) and the plastic scintillator NE102A. Preliminary modeling of the afterglow is presented.

  8. Novel methods for measuring afterglow in developmental scintillators for X-ray and neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Bartle, C.M., E-mail: m.bartle@gns.cri.nz [National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5040 (New Zealand); Edgar, A.; Dixie, L.; Varoy, C. [School of Chemistry and Physics, Victoria University of Wellington, Wellington 6140 (New Zealand); Piltz, R. [Bragg Institute, ANSTO, PMB 1, Menai NSW 2234 (Australia); Buchanan, S.; Rutherford, K. [School of Chemistry and Physics, Victoria University of Wellington, Wellington 6140 (New Zealand)

    2011-09-21

    In this paper we discuss two novel methods of measuring afterglow in scintillators. One method is designed for X-ray detection and the other for neutron detection applications. In the first method a commercial fan-beam scanner of basic design similar to those seen at airports is used to deliver a typically 12 ms long X-ray pulse to a scintillator by passing the test equipment through the scanner on the conveyor belt. In the second method the thermal neutron beam from a research reactor is incident on the scintillator. The beam is cut-off in about 1 ms using a {sup 10}B impregnated aluminum pneumatic shutter, and the afterglow is recorded on a dual range storage oscilloscope to capture both the steady state intensity and the weak decay. We describe these measurement methods and the results obtained for a range of developmental ceramic and glass scintillators, as well as some standard scintillators such as NaI(Tl), LiI(Eu) and the plastic scintillator NE102A. Preliminary modeling of the afterglow is presented.

  9. Digital pulse shape discrimination between fast neutrons and gamma rays with para-terphenyl scintillator

    Science.gov (United States)

    Chepurnov, A. S.; Kirsanov, M. A.; Klenin, A. A.; Klimanov, S. G.; Kubankin, A. S.

    2017-12-01

    In the presented work, we investigated several digital methods of a discrimination signals from fast neutrons and gamma quanta. The experimental setup consists of a Pu-Be neutron source, a scintillation detector with an organic para-terphenyl monocrystal, and a digitizer (CAEN DT5730, 500 MS/s). Mixed waveform sequences were stored and then separated by pulse shape. Four methods were used for signals separation. Comparison of the traditional and the new methods of Figure of Merit (FOM) calculation is given. FOM = 1.5 was obtained in our setup for the minimum threshold value. A scintillation detector with a para-terphenyl crystal was used to measure neutron yield in the neutron generator with carbon nanotubes.

  10. Device for characterization of fissile materials comprising at least a neutron detector embedded inside a scintillator for gamma radiation detection

    International Nuclear Information System (INIS)

    Bernard, P.; Dherbey, J.R.; Bosser, R.; Berne, R.

    1989-01-01

    Fissile materials, for instance in radioactive wastes, are characterized by measurement of prompt and delayed neutrons and gamma radiation from induced fission by a neutron source. Gamma radiation is detected with a scintillation detector associated to a photomultiplier, the scintillation material is at the same time a moderator for thermalization of fast neutrons emitted by the neutron source and also of neutrons from spontaneous fission, (α, n) reactions and neutrons from induced fission in the fissile material. Preferentially the moderator is made of Altustipe (Plexiglas with anthracene as additive) [fr

  11. Microstructured boron foil scintillating G-GEM detector for neutron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Takeshi, E-mail: fujiwara-t@aist.go.jp [Research Institute for Measurement and Analytical Instrumentation, Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan); Center for Advanced Photonics, Neutron Beam Technology Team, RIKEN, Saitama (Japan); Bautista, Unico [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo (Japan); Philippine Nuclear Research Institute-Department of Science and Technology (PNRI-DOST), Commonwealth Avenue, Diliman, Quezon City (Philippines); Mitsuya, Yuki [Nuclear Professional School, The University of Tokyo, Tokai-mura, Naka-gun, Ibaraki (Japan); Takahashi, Hiroyuki [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo (Japan); Yamada, Norifumi L. [Neutron Science Laboratory, Institute of Material Structure Science, High Energy Accelerator Research Organization (KEK) (Japan); Otake, Yoshie; Taketani, Atsushi [Center for Advanced Photonics, Neutron Beam Technology Team, RIKEN, Saitama (Japan); Uesaka, Mitsuru [Nuclear Professional School, The University of Tokyo, Tokai-mura, Naka-gun, Ibaraki (Japan); Toyokawa, Hiroyuki [Research Institute for Measurement and Analytical Instrumentation, Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan)

    2016-12-01

    In this study, a new simple neutron imaging gaseous detector was successfully developed by combining a micro-structured {sup 10}B foil, a glass gas electron multiplier (G-GEM), and a mirror–lens–charge-coupled device (CCD)–camera system. The neutron imaging system consists of a chamber filled with Ar/CF{sub 4} scintillating gas mixture. Inside this system, the G-GEM is mounted for gas multiplication. The neutron detection in this system is based on the reaction between {sup 10}B and neutrons. A micro-structured {sup 10}B is developed to overcome the issue of low detection efficiency. Secondary electrons excite Ar/CF{sub 4} gas molecules, and high-yield visible photons are emitted from those excited gas molecules during the gas electron multiplication process in the G-GEM holes. These photons are easily detected by a mirror–lens–CCD–camera system. A neutron radiograph is then simply formed. We obtain the neutron images of different materials with a compact accelerator-driven neutron source. We confirm that the new scintillating G-GEM-based neutron imager works properly with low gamma ray sensitivity and exhibits a good performance as a new simple digital neutron imaging device.

  12. Scintillating-fiber imaging detector for 14-MeV neutrons

    International Nuclear Information System (INIS)

    Ress, D.; Lerche, R.A.; Ellis, R.J.; Heaton, G.W.; Nelson, M.B.; Mant, G.; Lehr, D.E.

    1994-01-01

    The authors have created a detector to image the neutrons emitted by imploded inertial-confinement fusion targets. The 14-MeV neutrons, which are produced by deuterium-tritium fusion events in the target, pass through an aperture to create an image on the detector. The neutron radiation is converted to blue light (430 nm) with a 20-cm-square array of plastic scintillating fibers. Each fiber is 10-cm long with a 1-mm-square cross section; approximately 35-thousand fibers make up the array. The resulting blue-light image is reduced and amplified by a sequence of fiber-optic tapers and image intensifiers, then acquired by a CCD camera. The fiber-optic readout system was tested optically for overall throughput the resolution. The authors plan to characterize the scintillator array reusing an ion-beam neutron source as well as DT-fusion neutrons emitted by inertial confinement targets. Characterization experiments will measure the light-production efficiency, spatial resolution, and neutron scattering within the detector. Several neutron images of laser-fusion targets have been obtained with the detector. Several neutron images of laser-fusion targets have been obtained with the detector. They describe the detector and their characterization methods, present characterization results, and give examples of the neutron images

  13. A neutron spin echo spectrometer with two optimal field shape coils for neutron spin precession

    International Nuclear Information System (INIS)

    Takeda, T.; Ebisawa, T.; Tasaki, S.; Ito, Y.; Takahashi, S.; Yoshizawa, H.

    1995-01-01

    We have designed and have been constructing at the C 2-2 cold neutron guide port of JRR-3M, JAERI, a neutron spin echo spectrometer (NSE) which is equipped with two optimal field shape (OFS) coils for neutron spin precession with the maximum field integral of 0.22 T m, an assembly of position sensitive detectors (PSD), a converging polarizer and a wide area analyzer. The dynamic range of scattering vector Q covers from 0.005 A -1 to 0.2 A -1 and that of energy hω from 10 neV to 30 μeV. Performance tests of the OFS coils show that the inhomogeneity of the magnetic field integral in the OFS coils with the spiral coils is so small that the NSE signal amplitude decreases little even for the neutron cross section of 30 mm diameter as the Fourier time t increases up to 25 ns, though the precession coils are close to iron covers of the neighboring neutron guide. This verifies that the OFS precession coils are appropriate for this NSE spectrometer. Another test experiment shows that the homogeneity condition of the precession magnet is loosened by use of PSD. (orig.)

  14. Small angle neutron scattering using a triple axis spectrometer

    International Nuclear Information System (INIS)

    Ahmed, F.U.; Goyal, P.S.; Kamal, L.; Yunus, S.M.; Datta, T.K.; Rahman, M.O.; Azad, A.K.; Begum, S.; Zakaria, A.K.

    1994-01-01

    SANS techniques has been developed on a triple axis neutron spectrometer at TRIGA Mark II (3 MW) research reactor, AERE, Savar, Dhaka, Bangladesh. Double crystal (with very small mosaic spread ∼ 1 min.) diffraction known as Bonse and Hart's method has been employed. Such a device is a useful tool for small angle scattering in the Q range between 10 -5 and 10 -1 Angstroms -1 and for real time experiments at short time scales. Therefore, large objects and large distance interparticle correlations can be easily investigated. The results of SANS' measurements using alumina (A1 2 0 3 ) sample are presented. The radius of gyration has been determined and the data has been fitted to the scattering function of a sphere. 9 refs., 6 figs.,

  15. Charged-particle magnetic-quadrupole spectrometer for neutron induced reactions

    International Nuclear Information System (INIS)

    Haight, R.C.; Grimes, S.M.; Tuckey, B.J.; Anderson, J.D.

    1975-01-01

    A spectrometer has been developed for measuring the charged particle production cross sections and spectra in neutron-induced reactions. The spectrometer consists of a magnetic quadrupole doublet which focuses the charged particles onto a silicon surface barrier detector telescope which is 2 meters or more from the irradiated sample. Collimators, shielding, and the large source-to-detector distance reduce the background enough to use the spectrometer with a 14-MeV neutron source producing 4 . 10 12 n/s. The spectrometer has been used in investigations of proton, deuteron, and alpha particle production by 14-MeV neutrons incident on various materials. Protons with energies as low as 1.1 MeV have been measured. The good resolution of the detectors has also made possible an improved measurement of the neutron- neutron scattering length from the 0 0 proton spectrum from deuteron breakup by 14-MeV neutrons

  16. Determination of workplace neutron spectra at a high energy hadron accelerator using active and passive Bonner sphere spectrometers

    International Nuclear Information System (INIS)

    Bedogni, R.; Esposito, A.; Chiti, M.

    2008-01-01

    In the framework of the 2006 experimental benchmark organized at the GSI (Darmstadt, Germany) by the EC CONRAD network, a neutron dosimetry intercomparison was performed in a workplace field around a carbon target hit by 400 MeV/u 12 C ions. The radiation protection group of the INFN-LNF participated to the intercomparison with a Bonner sphere spectrometer equipped with an active 6 LiI(Eu) scintillator and a set of passive detectors, namely MCP-6s (80mgcm -2 )/MCP-7 TLD pairs from TLD Poland. Both active and passive spectrometers, independently tested and calibrated, were used to determine the field and dosimetric quantities in the measurement point. The FRUIT unfolding code, developed at the INFN-LNF radiation protection group, was used to unfold the raw BSS data. This paper compares the results of the active or passive spectrometers, obtaining a satisfactory agreement in terms of both spectrum shape and value of the integral quantities, as the neutron fluence or the ambient dose equivalent. These results allow qualifying the BSS based on TLD pairs as a reliable passive method to be used around high energy particle accelerators even in low dose rate areas. This is particularly useful in those workplaces where the active instruments could be disturbed by the presence of pulsed fields, large photon fluence or electromagnetic noise

  17. Design, construction and description of a triple axis neutron crystal spectrometer

    International Nuclear Information System (INIS)

    Fulfaro, R.; Vinhas, L.A.; Fuhrmann, C.; Liguori Neto, R.; Parente, C.B.R.

    1977-01-01

    Integrating the neutron inelastic scattering plan in IEA (Sao Paulo, Brazil) it was completely designed and constructed there, a triple axis neutron spectrometer. The details about construction and design of the spectrometer are described. Basic principles about the experimental method which utilizes neutron coherent inelastic scattering in order to determine the relation dispersion between frequency and wave vector of the crystalline vibrations, are presented [pt

  18. Neutron-gamma discrimination via PSD plastic scintillator and SiPMs

    Science.gov (United States)

    Taggart, M. P.; Payne, C.; Sellin, P. J.

    2016-10-01

    The reduction in availability and inevitable increase in cost of traditional neutron detectors based on the 3He neutron capture reaction has resulted in a concerted effort to seek out new techniques and detection media to meet the needs of national nuclear security. Traditionally, the alternative has been provided through pulse shape discrimination (PSD) using liquid scintillators. However, these are not without their own inherent issues, primarily concerning user safety and ongoing maintenance. A potential system devised to separate neutron and gamma ray pulses utilising the PSD technique takes advantage of recent improvements in silicon photomultiplier (SiPM) technology and the development of plastic scintillators exhibiting the PSD phenomena. In this paper we present the current iteration of this ongoing work having achieved a Figure of Merit (FoM) of 1.39 at 1.5 MeVee.

  19. Calibration of the time response functions of a quenched plastic scintillator for neutron time of flight

    CERN Document Server

    Chen, J B; Peng, H S; Tang, C H; Zhang, B H; Ding, Y K; Chen, M; Chen, H S; Li, C G; Wen, T S; Yu, R Z

    2002-01-01

    The time response functions of an ultrafast quenched plastic scintillation detector used to measure neutron time of flight spectra were calibrated by utilizing cosmic rays and implosion neutrons from DT-filled capsules at the Shenguang II laser facility. These sources could be regarded as delta function pulses due to their much narrower time widths than those of the time response functions of the detection system. The results showed that the detector responses to DT neutrons and to cosmic rays were 1.18 and 0.96 ns FWHM, respectively.

  20. The efficient neutron-gamma pulse shape discrimination with small active volume scintillation detector

    International Nuclear Information System (INIS)

    Phan Van Chuan; Nguyen Duc Hoa; Nguyen Xuan Hai; Nguyen Ngoc Anh; Tuong Thi Thu Huong; Nguyen Nhi Dien; Pham Dinh Khang

    2016-01-01

    A small detector with EJ-301 liquid scintillation was manufactured for the study on the neutron-gamma pulse shape discrimination. In this research, four algorithms, including Threshold crossing time (TCT), Pulse gradient analysis (PGA), Charge comparison method (CCM), and Correlation pattern recognition (CPR) were developed and compared in terms of their discrimination effectiveness between neutrons and gamma rays. The figures of merits (FOMs) obtained for 100 ÷ 2000 keVee (keV energy electron equivalent) neutron energy range show the charge comparison method was the most efficient of the four algorithms. (author)

  1. Discriminated neutron and X-ray radiography using multi-color scintillation detector

    International Nuclear Information System (INIS)

    Nittoh, Koichi; Takahara, Takeshi; Yoshida, Tadashi; Tamura, Toshiyuki

    1999-01-01

    A new conversion screen Gd 2 O 2 S:Eu is developed, which emits red light on irradiation by thermal neutrons. By applying this in combination with the currently used Gd 2 O 2 S:Tb, a green-light scintillator, in the radiography under a neutron + X-ray coexisting field, we can easily separate the neutron image and the X-ray image by simple color-image processing. This technique enables a non-destructive and detailed inspection of industrial products composed both of light elements (water, plastics, etc.) and heavy elements (metals), widening the horizon of new applications

  2. Discriminated neutron and X-ray radiography using multi-color scintillation detector

    CERN Document Server

    Nittoh, K; Yoshida, T; Tamura, T

    1999-01-01

    A new conversion screen Gd sub 2 O sub 2 S:Eu is developed, which emits red light on irradiation by thermal neutrons. By applying this in combination with the currently used Gd sub 2 O sub 2 S:Tb, a green-light scintillator, in the radiography under a neutron + X-ray coexisting field, we can easily separate the neutron image and the X-ray image by simple color-image processing. This technique enables a non-destructive and detailed inspection of industrial products composed both of light elements (water, plastics, etc.) and heavy elements (metals), widening the horizon of new applications.

  3. The TOFOR Neutron Spectrometer For High-Performance Measurements of D Plasma Fuel Ion Properties

    International Nuclear Information System (INIS)

    Johnson, M. Gatu; Giacomelli, L.; Hjalmarsson, A.; Weiszflog, M.; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Hellesen, C.; Ronchi, E.; Sjoestrand, H.; Kaellne, J.; Gorini, G.; Tardocch, M.

    2008-01-01

    The impact of scattered neutrons on the total flux reaching the TOFOR spectrometer at JET has been studied to allow for improvement of the data analysis. The scattered neutrons are demonstrated to contribute significantly to the flux. This will have implications for any neutron diagnostic on ITER

  4. Calculation of Multisphere Neutron Spectrometer Response Functions in Energy Range up to 20 MeV

    CERN Document Server

    Martinkovic, J

    2005-01-01

    Multisphere neutron spectrometer is a basic instrument of neutron measurements in the scattered radiation field at charged-particles accelerators for radiation protection and dosimetry purposes. The precise calculation of the spectrometer response functions is a necessary condition of the propriety of neutron spectra unfolding. The results of the response functions calculation for the JINR spectrometer with LiI(Eu) detector (a set of 6 homogeneous and 1 heterogeneous moderators, "bare" detector within cadmium cover and without it) at two geometries of the spectrometer irradiation - in uniform monodirectional and uniform isotropic neutron fields - are given. The calculation was carried out by the code MCNP in the neutron energy range 10$^{-8}$-20 MeV.

  5. Advanced Multilayer Composite Heavy-Oxide Scintillator Detectors for High Efficiency Fast Neutron Detection

    Science.gov (United States)

    Ryzhikov, Vladimir D.; Naydenov, Sergei V.; Pochet, Thierry; Onyshchenko, Gennadiy M.; Piven, Leonid A.; Smith, Craig F.

    2018-01-01

    We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium - designated as ZEBRA - serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron

  6. A gaseous scintillation counter filled with He3 for neutron spectrometry

    International Nuclear Information System (INIS)

    Baldin, S.A.; Matveev, V.V.

    1962-01-01

    The paper describes a gas plant and gaseous scintillation counter, and gives the results of experiments on the recording and spectrometry of neutron beams using a gaseous scintillation counter filled with a mixture of 10% xenene and 90% helium-3 at an overall pressure of 20 ata. Data are given on the design of the gas plant, which makes it possible to operate the counter continuously over long periods of time, as well as providing the required gas mixtures at overall pressures of up to 60 atm and ensuring constant freedom of the gas from contamination. In addition, the paper presents the results of research on the counter's energy resolution and linearity at different energy levels and indicates its efficiency in gamma fields of intensity up to 3 r/h; the possibility of extending the working energy-range of gaseous scintillation counters filled with helium-3 is also considered. (author) [fr

  7. Scintillating-Glass-Fiber neutron sensors, their application and performance for plutonium detection and monitoring

    International Nuclear Information System (INIS)

    Seymour, R.S.; Richardson, B.; Morichi, M.; Bliss, M.; Craig, R.A.; Sunberg, D.S.

    1998-01-01

    Most neutron detection sensors presently employ 3 He gas-filled detectors. Despite their excellent performance and widespread use, there are significant limitations to this technology. A significant alternative neutron sensor utilizing neutron-active material incorporated into a glass scintillator is presented that offers novel commercial sensors not possible or practical with gas tube technology. The scintillating optical fiber permits sensors with a multitude of sizes ranging from devices of a single fiber of 150μm to sensors with tens of thousands of fibers with areas as large as 5m 2 depending on the neutron flux to be measured. A second significant advantage is the use of high-speed electronics that allow a greater dynamic range, not possible with gas detectors. These sensors are flexible, conformable and less sensitive to vibration that optimizes the source-to-detector geometry and provides robust performance in field applications. The glass-fibers are sensitive to both gamma rays and neutrons. However the coincidence electronics are optimized for neutron to gamma ray discrimination allowing very sensitive measurements with a low false-alarm rate. Applications include SNM surveillance, material control and accountability (MC and A), safeguard inspections, Pu health physics / bioassay and environmental characterization. (author)

  8. Neutronic calculations in support of the design of the ITER High Resolution Neutron Spectrometer

    International Nuclear Information System (INIS)

    Moro, F.; Esposito, B.; Marocco, D.; Villari, R.; Petrizzi, L.; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Johnson, M. Gatu; Dapena, M.

    2011-01-01

    This paper presents the results of neutronic calculations performed to address important issues related to the optimization of the ITER HRNS (High resolution Neutron Spectrometer) design, in particular concerning the definition of the collimator and the choice of the detector system. The calculations have been carried out using the MCNP5 Monte Carlo code in a full 3-D geometry. The HRNS collimation system has been included in the latest MCNP ITER 40 o model (Alite-4). The ITER scenario 2 reference DT plasma fusion neutron source peaked at 14.1 MeV with Gaussian energy distribution has been used. Neutron fluxes and energy spectra (>1 MeV) have been evaluated at different positions along the HRNS collimator and at the detector location. The noise-to-signal ratio (i.e. the ratio of collided to uncollided neutrons), the breakdown of the collided spectrum into its components, the dependency on the first wall aperture and the gamma-ray spectra at the detector position have also been analyzed. The impact of the results on the design of the HRNS diagnostic system is discussed.

  9. Response of CsI:Pb Scintillator Crystal to Neutron Radiation

    Science.gov (United States)

    Costa Pereira, Maria da Conceição; Filho, Tufic Madi; Berretta, José Roberto; Náhuel Cárdenas, José Patrício; Iglesias Rodrigues, Antonio Carlos

    2018-01-01

    The helium-3 world crisis requires a development of new methods of neutron detection to replace commonly used 3He proportional counters. In the past decades, great effort was made to developed efficient and fast scintillators to detect radiation. The inorganic scintillator may be an alternative. Inorganic scintillators with much higher density should be selected for optimal neutron detection efficiency taking into consideration the relevant reactions leading to light emission. These detectors should, then, be carefully characterized both experimentally and by means of advanced simulation code. Ideally, the detector should have the capability to separate neutron and gamma induced events either by amplitude or through pulse shape differences. As neutron sources also generate gamma radiation, which can interfere with the measurement, it is necessary that the detector be able to discriminate the presence of such radiation. Considerable progress has been achieved to develop new inorganic scintillators, in particular increasing the light output and decreasing the decay time by optimized doping. Crystals may be found to suit neutron detection. In this report, we will present the results of the study of lead doped cesium iodide crystals (CsI:Pb) grown in our laboratory, using the vertical Bridgman technique. The concentration of the lead doping element (Pb) was studied in the range 5x10-4 M to 10-2 M . The crystals grown were subjected to annealing (heat treatment). In this procedure, vacuum of 10-6 mbar and continuous temperature of 350°C, for 24 hours, were employed. In response to neutron radiation, an AmBe source with energy range of 1 MeV to 12 MeV was used. The activity of the AmBe source was 1Ci Am. The fluency was 2.6 x 106 neutrons/second. The operating voltage of the photomultiplier tube was 1700 V; the accumulation time in the counting process was 600 s and 1800 s. The scintillator crystals used were cut with dimensions of 20 mm diameter and 10 mm height.

  10. Neutron detection in a high gamma-ray background with EJ-301 and EJ-309 liquid scintillators

    International Nuclear Information System (INIS)

    Stevanato, L.; Cester, D.; Nebbia, G.; Viesti, G.

    2012-01-01

    Using a fast digitizer, the neutron–gamma discrimination capability of the new liquid scintillator EJ-309 is compared with that obtained using standard EJ-301. Moreover the capability of both the scintillation detectors to identify a weak neutron source in a high gamma-ray background is demonstrated. The probability of neutron detection is PD=95% at 95% confidence level for a gamma-ray background corresponding to a dose rate of 100 μSv/h.

  11. {sup 6}LiF:ZnS(Ag) Neutrons Scintillator Detector Configuration for Optimal Readout

    Energy Technology Data Exchange (ETDEWEB)

    Osovizky, A. [NIST Center for Neutron Research, Gaithersburg, Maryland (United States); Rotem Industries Ltd, Rotem Industrial Park (Israel); University of Maryland, College park, Maryland (United States); Yehuda-Zada, Y.; Ghelman, M.; Tsai, P.; Thompson, A.K. [Nuclear Research Center Negev, Beer-Sheva (Israel); Pritchard, K.; Ziegler, J.B.; Ibberson, R.M.; Majkrzak, C.F.; Maliszewskyj, N.C. [NIST Center for Neutron Research, Gaithersburg, Maryland (United States)

    2015-07-01

    A Chromatic Analysis Neutron Diffractometer Or Reflectometer (CANDOR) is under development at the NIST Center for Neutron Research (NCNR). The CANDOR neutron sensor will rely on scintillator material for detecting the neutrons scattered by the sample under test. It consists of {sup 6}LiF:ZnS(Ag) scintillator material into which wavelength shifting (WLS) fibers have been embedded. Solid state photo-sensors (silicon photomultipliers) coupled to the WLS fibers are used to detect the light produced by the neutron capture event ({sup 6}Li (n,α) {sup 3}H reaction) and ionization of the ZnS(Ag). This detector configuration has the potential to accomplish the CANDOR performance requirements for efficiency of 90% for 5 A (3.35 meV) neutrons with high gamma rejection (10{sup 7}) along with compact design, affordable cost and materials availability. However this novel design includes challenges for precise neutron detection. The recognizing of the neutron signature versus the noise event produce by gamma event cannot be easy overcome by pulse height discrimination obstacle as can be achieved with {sup 3}He gas tube. Furthermore the selection of silicon photomultipliers (SiPM) as the light sensor maintains the obstacle of dark noise that does not exist when a photomultiplier tube is coupled to the scintillator. A proper selection of SiPM should focus on increasing the output signal and reducing the dark noise in order to optimize the detection sensitivity and to provide a clean signal pulse shape discrimination. The main parameters for evaluation are: - Quantum Efficiency (QE) - matching the SiPM peak QE with the peak transmission wavelength emission of the WLS. - Recovery time - a short recovery time is preferred to minimize the pulse width beyond the intrinsic decay time of the scintillator crystal (improves the gamma rejection based output pulse shape (time)). - Diode dimensions -The dark noise is proportional to the diode active area while the signal is provided by the

  12. Spent Nuclear Fuel Cask and Storage Monitoring with {sup 4}He Scintillation Fast Neutron Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hee jun; Kelley, Ryan P; Jordan, Kelly A [Univ. of Florida, Florida (United States); Lee, Wanno [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chung, Yong Hyun [Yonsei Univ., Wonju (Korea, Republic of)

    2014-10-15

    With this increasing quantity of spent nuclear fuel being stored at nuclear plants across S. Korea, the demand exists for building a long-term disposal facility. However, the Korean government first requires a detailed plan for the monitoring and certification of spent fuel. Several techniques have been developed and applied for the purpose of spent fuel monitoring, including the digital Cerenkov viewing device (DCVD), spent fuel attribute tester (SFAT), and FORK detector. Conventional gamma measurement methods, however, suffer from a lack of nuclear data and interfering background radiation. To date, the primary method of neutron detection for spent fuel monitoring has been through the use of thermal neutron detectors such as {sup 3}He and BF{sub 3} proportional counters. Unfolding the neutron spectrum becomes extremely complicated. In an attempt to overcome these difficulties, a new fast neutron measurement system is currently being developed at the University of Florida. This system is based on the {sup 4}He scintillation detector invented by Arktis Radiation Detectors Ltd. These detectors are a relatively new technological development and take advantage of the high {sup 4}He cross-section for elastic scattering at fast neutron energies, particularly the resonance around 1 MeV. This novel {sup 4}He scintillation neutron detector is characterized by its low electron density, leading to excellent gamma rejection. This detector also has a fast response time on the order of nanoseconds and most importantly, preserves some neutron energy information since no moderator is required. Additionally, these detectors rely on naturally abundant {sup 4}He as the fill gas. This study proposes a new technique using the neutron spectroscopy features of {sup 4}He scintillation detectors to maintain accountability of spent fuel in storage. This research will support spent fuel safeguards and the detection of fissile material, in order to minimize the risk of nuclear proliferation

  13. Neutron spectrometry with organic scintillation detector; Espectrometria de nuetrones con cristales de centelleo organicos

    Energy Technology Data Exchange (ETDEWEB)

    Butragueno Casdo, J L

    1972-07-01

    This work describes a fast neutron spectrometer using a stilbene crystal as head detector with pulse shape discrimination (P.S.D.) to reject gamma background. Tre experimental procedure involves the P.S.D., the measurements to calibrate the spectrometer and the corrections for several factors, mainly the non-linear response of the stilbene. Results of the measurements with the reaction D{sup 2}(d,n)He{sup 3}, and with an Am-Be neutron source are presented. It is also presented the measurement of the spectrum of the fast reactor CCRAl-1. (Author) 17 refs.

  14. Development of a large area thermal neutron detector based on a scintillator

    International Nuclear Information System (INIS)

    Engels, Ralf

    2012-01-01

    In the present work, the development and construction of a detector prototype based on wavelength shifting fiber in combination with a scintillator has been investigated and optimized. This development aims at an alternative for large area neutron detectors based on "3He detectors, which was the main construction in the past. After the study of the components and assemblies, such as: the scintillator, the wavelength-shifting-fibers and available photomultiplier tubes, the construction of the first prototype module begun. The neutron converter was selected as a "6LiF/ZnS scintillator, which produces a big light yield per absorbed neutron. The prototype itself is square and has an edge length of 30 cm in combination with two orthogonal layers of crossed wavelength-shifting-fibers. The top fiber layer, which is closer to the "6LiF/ZnS top scintillator produces the x-coordinates and the lower layer produces the y-coordinates for each event. In the prototype, MSJ-fibers from the company Kuraray were used with 1 mm diameter and spacing in the top layer of 1.5 mm and 1 mm in the lower layer. Due to the orthogonal arrangement of the wires in the two layers, one may identify where the neutron was absorbed in the scintillator and produced the light yield. In order to reduce the light loss of the absorbed photons inside the fibers, a bending radius of greater than 20 mm was used and achieved by warming up the fibers to 80 C during the bending process. The increased temperature reduces the crack formation in the fibers which increases the light loss. At this time it is expected that a photomultiplier from Hamamatsu with 256 individual pixels for readout will be used. This H9500 flat panel photomultiplier has the advantage of readout of all fibers of the prototype in one photomultiplier housing. In combination with integrated readout electronics one can minimize the homogeneity/gain differences of the photocathode pixels, the different light loss in each fiber, and the gain

  15. Development of a two-dimensional imaging detector based on a neutron scintillator with wavelength-shifting fibers

    CERN Document Server

    Sakai, K; Oku, T; Morimoto, K; Shimizu, H M; Tokanai, F; Gorin, A; Manuilov, I V; Ryazantsev, A; Ino, T; Kuroda, K; Suzuki, J

    2002-01-01

    For evaluating neutron optical devices, a two-dimensional (2D) detector based on a neutron scintillator with wavelength-shifting fibers has been developed at RIKEN. We have investigated a ZnS(Ag)+LiF and a Li glass plate as neutron scintillators with the coding technique for realizing the large sensitive area of 50 x 50 mm sup 2. After fabricating the 2D detector, its performance was tested using cold neutrons at JAERI. As a result, a spatial resolution of propor to 1.0 mm was obtained. (orig.)

  16. Monte Carlo simulation of neutron detection efficiency for NE213 scintillation detector

    International Nuclear Information System (INIS)

    Xi Yinyin; Song Yushou; Chen Zhiqiang; Yang Kun; Zhangsu Yalatu; Liu Xingquan

    2013-01-01

    A NE213 liquid scintillation neutron detector was simulated by using the FLUKA code. The light output of the detector was obtained by transforming the secondary particles energy deposition using Birks formula. According to the measurement threshold, detection efficiencies can be calculated by integrating the light output. The light output, central efficiency and the average efficiency as a function of the front surface radius of the detector, were simulated and the results agreed well with experimental results. (authors)

  17. Influence of nuclear cross section data at efficiency calculation of the 3He semiconductor neutron spectrometer

    International Nuclear Information System (INIS)

    Avdic, S.; Pesic, M.

    1992-01-01

    The ORTEC 580 Neutron Spectrometer system contains a detector unit in diode coincidence arrangement for measurement of fast neutron spectrum in the energy range from 1 MeV to 14 MeV. Numerical code HE3 for computation of semiconductor 3 He detector efficiency in a collimated neutron beam is based on analytical method in infinite diode approximation and Monte Carlo method for real spectrometer geometry. Calculations are performed in the first collision approximation in the detector active volume including evaluation of correction factors. Accuracy of relative detector efficiency calculation is improved by using neutron cross section from nuclear library ENDF/B-6. (author)

  18. Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators

    International Nuclear Information System (INIS)

    Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.

    2016-01-01

    The recently developed Cs 2 LiYCl 6 :Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the 6 Li(n,α)t reaction while for the fast neutrons the 35 Cl(n,p) 35 S and 35 Cl(n,α) 32 P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9–3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35 Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7 LiF target. We tested a CLYC detector 6 Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7 Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  19. The polarized neutron spectrometer REMUR at the pulsed reactor IBR-2

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Zhernenkov, K.N.; Kozhevnikov, S.V.; Nikitenko, Yu.V.; Petrenko, A.V.; Lauter, H.J.; Lauter-Pasyuk, V.

    2004-01-01

    At the Laboratory of Neutron Physics (JINR, Dubna) the new polarized neutron spectrometer REMUR has been constructed and commissioned. The spectrometer REMUR is dedicated to investigations of multilayers and surfaces by polarized neutron reflection and of the inhomogeneous state of solids by diffuse small-angle polarized neutron scattering. The spectrometer operates in the neutron wavelength interval 1-10 Angstroem. In the reflectometry mode it allows one to complete polarization analysis and neutron position-sensitive detection within the solid angle of scattering 2.2·10 -4 rad. The spectrometer ensures good statistics of the reflectometric data in the scattering wave vector interval 3·10 -3 - 5·10 -1 Angstroem -1 . In the small-angle scattering mode the spectrometer allows the investigation of neutron scattering processes without spin-flip over the detector's neutron registration solid angle interval from 4·10 -3 to 10 -1 rad and the scattering wave vector interval from 0.006-0.15 to 0.03-0.7 Angstroem -1 , respectively

  20. Neutron/gamma pulse shape discrimination in plastic scintillators: Preparation and characterization of various compositions

    International Nuclear Information System (INIS)

    Blanc, Pauline; Hamel, Matthieu; Dehé-Pittance, Chrystèle; Rocha, Licinio; Pansu, Robert B.; Normand, Stéphane

    2014-01-01

    This work deals with the preparation and evaluation of plastic scintillators for neutron/gamma pulse shape discrimination (PSD). We succeeded in developing a plastic scintillator with good neutron/gamma discrimination properties in the range of what is already being commercialized. Several combinations of primary and secondary fluorophores were implemented in chemically modified polymers. These scintillators were fully characterized by fluorescence spectroscopy and under neutron irradiation. The materials proved to be stable for up to 5 years without any degradation of PSD properties. They were then classified in terms of their PSD capabilities and light yield. Our best candidate, 28.6 wt% of primary fluorophore with a small amount of secondary fluorophore, shows promising PSD results and is particularly suited to industrial development, because its preparation does not involve the use of expensive or exotic compounds. Furthermore, even at the highest prepared concentration, high stability over time was observed. As a proof of concept, one sample with dimensions 109 mm ∅×114 mm height (≈1 L) was prepared

  1. Neutron/gamma pulse shape discrimination in plastic scintillators: Preparation and characterization of various compositions

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, Pauline [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France); Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (CNRS UMR 8531), École Normale Supérieure de Cachan, 61 Avenue du Président Wilson, F-94235 Cachan cedex (France); Hamel, Matthieu, E-mail: matthieu.hamel@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France); Dehé-Pittance, Chrystèle; Rocha, Licinio [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France); Pansu, Robert B. [Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (CNRS UMR 8531), École Normale Supérieure de Cachan, 61 Avenue du Président Wilson, F-94235 Cachan cedex (France); Normand, Stéphane [CEA, LIST, Laboratoire Capteurs et Architectures Électroniques, F-91191 Gif-sur-Yvette (France)

    2014-06-01

    This work deals with the preparation and evaluation of plastic scintillators for neutron/gamma pulse shape discrimination (PSD). We succeeded in developing a plastic scintillator with good neutron/gamma discrimination properties in the range of what is already being commercialized. Several combinations of primary and secondary fluorophores were implemented in chemically modified polymers. These scintillators were fully characterized by fluorescence spectroscopy and under neutron irradiation. The materials proved to be stable for up to 5 years without any degradation of PSD properties. They were then classified in terms of their PSD capabilities and light yield. Our best candidate, 28.6 wt% of primary fluorophore with a small amount of secondary fluorophore, shows promising PSD results and is particularly suited to industrial development, because its preparation does not involve the use of expensive or exotic compounds. Furthermore, even at the highest prepared concentration, high stability over time was observed. As a proof of concept, one sample with dimensions 109 mm ∅×114 mm height (≈1 L) was prepared.

  2. Response of Inorganic Scintillators to Neutrons of 3 and 15 MeV Energy

    CERN Document Server

    Lucchini, M; Pizzichemi, M; Chipaux, R; Jacquot, F; Mazue, H; Wolff, H; Lecoq, P; Auffray, E

    2014-01-01

    In the perspective of the development of future high energy physics experiments, homogeneous calorimeters based on inorganic scintillators can be considered for the detection of hadrons (e.g., calorimeter based on dual-readout technique). Although of high importance in the high energy physics framework as well as for homeland security applications, the response of these inorganic scintillators to neutrons has been only scarcely investigated. This paper presents results obtained using five common scintillating crystals (of size around 2x2x2 cm 3), namely lead tungstate (PbWO4), bismuth germanate (BGO), cerium fluoride (CeF3), Ce-doped lutetium-yttrium orthosilicate (LYSO:Ce) and lutetium aluminum garnet (LuAG:Ce) in a pulsed flux of almost mono-energetic (similar to 3 MeV and similar to 15 MeV) neutrons provided by the Van de Graff accelerator SAMES of CEA Valduc. Energy spectra have been recorded, calibrated and compared with Geant4 simulations computed with different physics models. The neutron detection eff...

  3. Design and validation of a photon insensitive multidetector neutron spectrometer based on Dysprosium activation foils

    International Nuclear Information System (INIS)

    Gómez-Ros, J.M.; Bedogni, R.; Palermo, I.; Esposito, A.; Delgado, A.; Angelone, M.; Pillon, M.

    2011-01-01

    This communication describes a photon insensitive passive neutron spectrometer consisting of Dysprosium (Dy) activation foils located along three perpendicular axes within a single moderating polyethylene sphere. The Monte Carlo code MCNPX 2.6 was used to optimize the spatial arrangement of the detectors and to derive the spectrometer response matrix. Nearly isotropic response in terms of neutron fluence for energies up to 20 MeV was obtained by combining the readings of the detectors located at the same radius value. The spectrometer was calibrated using a previously characterized 14 MeV neutron beam produced in the ENEA Frascati Neutron Generator (FNG). The overall uncertainty of the spectrometer response matrix at 14 MeV, assessed on the basis of this experiment, was ±3%.

  4. Bis(pinacolato)diboron as an additive for the detection of thermal neutrons in plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Mahl, Adam [Department of Physics and the Nuclear Science and Engineering Center (NuSEC), Colorado School of Mines, Golden, CO 80401 (United States); Yemam, Henok A.; Stuntz, John [Department of Chemistry and Geochemistry and the Materials Science Program Colorado School of Mines, Golden, CO 80401 (United States); Remedes, Tyler [Department of Physics and the Nuclear Science and Engineering Center (NuSEC), Colorado School of Mines, Golden, CO 80401 (United States); Sellinger, Alan [Department of Chemistry and Geochemistry and the Materials Science Program Colorado School of Mines, Golden, CO 80401 (United States); Greife, Uwe, E-mail: ugreife@mines.edu [Department of Physics and the Nuclear Science and Engineering Center (NuSEC), Colorado School of Mines, Golden, CO 80401 (United States)

    2016-04-21

    A readily available and inexpensive boron compound was tested as an additive for the detection of thermal neutrons in plastic scintillators. Bis(pinacolato)diboron (B{sub 2}Pin{sub 2}) was determined to be a compatible boron source (8.51 wt% boron, 1.70 wt% {sup 10}B) in poly(vinyltoluene) based matrices. Plastic scintillator blends of 1–20 wt% 2,5-diphenyloxazole (PPO), 0.1 wt% 1,4-bis(5-phenyloxazol-2-yl) benzene (POPOP) and 1–15 wt% B{sub 2}Pin{sub 2} were prepared that provided optical clarity, good mechanical properties, and the capability of thermal neutron detection. Independent of B{sub 2}Pin{sub 2} concentration, strong {sup 10}B neutron capture signals around 90 keV{sub ee} were observed at essentially constant light output. Increasing PPO concentration allowed for the use of pulse shape discrimination (PSD) in both fast and thermal neutron detection. High PPO concentrations appear to cause additional alpha quenching that affected the {sup 10}B neutron capture signal. Aging effects after storage in air for several months were observed, which led to degradation of performance and in some samples of mechanical stability.

  5. A directional fast neutron detector using scintillating fibers and an intensified CCD camera system

    International Nuclear Information System (INIS)

    Holslin, Daniel; Armstrong, A.W.; Hagan, William; Shreve, David; Smith, Scott

    1994-01-01

    We have been developing and testing a scintillating fiber detector (SFD) for use as a fast neutron sensor which can discriminate against neutrons entering at angles non-parallel to the fiber axis (''directionality''). The detector/convertor component is a fiber bundle constructed of plastic scintillating fibers each measuring 10 cm long and either 0.3 mm or 0.5 mm in diameter. Extensive Monte Carlo simulations were made to optimize the bundle response to a range of fast neutron energies and to intense fluxes of high energy gamma-rays. The bundle is coupled to a set of gamma-ray insenitive electro-optic intensifiers whose output is viewed by a CCD camera directly coupled to the intensifiers. Two types of CCD cameras were utilized: 1) a standard, interline RS-170 camera with electronic shuttering and 2) a high-speed (up to 850 frame/s) field-transfer camera. Measurements of the neutron detection efficiency and directionality were made using 14 MeV neutrons, and the response to gamma-rays was performed using intense fluxes from radioisotopic sources (up to 20 R/h). Recently, the detector was constructed and tested using a large 10 cm by 10 cm square fiber bundle coupled to a 10 cm diameter GEN I intensifier tube. We present a description of the various detector systems and report the results of experimental tests. ((orig.))

  6. Bis(pinacolato)diboron as an additive for the detection of thermal neutrons in plastic scintillators

    International Nuclear Information System (INIS)

    Mahl, Adam; Yemam, Henok A.; Stuntz, John; Remedes, Tyler; Sellinger, Alan; Greife, Uwe

    2016-01-01

    A readily available and inexpensive boron compound was tested as an additive for the detection of thermal neutrons in plastic scintillators. Bis(pinacolato)diboron (B_2Pin_2) was determined to be a compatible boron source (8.51 wt% boron, 1.70 wt% "1"0B) in poly(vinyltoluene) based matrices. Plastic scintillator blends of 1–20 wt% 2,5-diphenyloxazole (PPO), 0.1 wt% 1,4-bis(5-phenyloxazol-2-yl) benzene (POPOP) and 1–15 wt% B_2Pin_2 were prepared that provided optical clarity, good mechanical properties, and the capability of thermal neutron detection. Independent of B_2Pin_2 concentration, strong "1"0B neutron capture signals around 90 keV_e_e were observed at essentially constant light output. Increasing PPO concentration allowed for the use of pulse shape discrimination (PSD) in both fast and thermal neutron detection. High PPO concentrations appear to cause additional alpha quenching that affected the "1"0B neutron capture signal. Aging effects after storage in air for several months were observed, which led to degradation of performance and in some samples of mechanical stability.

  7. Digital discrimination of neutrons and γ-rays in liquid scintillators using pulse gradient analysis

    International Nuclear Information System (INIS)

    D'Mellow, B.; Aspinall, M.D.; Mackin, R.O.; Joyce, M.J.; Peyton, A.J.

    2007-01-01

    A method for the digital discrimination of neutrons and γ-rays in mixed radiation fields is described. Pulses in the time domain, arising from the interaction of photons and neutrons in a liquid scintillator, have been produced using an accepted empirical model and from experimental measurements with an americium-beryllium source. Neutrons and γ-rays have been successfully discriminated in both of these data sets in the digital domain. The digital discrimination method described in this paper is simple and exploits samples early in the life of the pulse. It is thus compatible with current embedded system technologies, offers a degree of immunity to pulse pile-up and heralds a real-time means for neutron/γ discrimination that is fundamental to many potential industrial applications

  8. Characterization of a scintillating lithium glass ultra-cold neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, B.; Rebenitsch, L.A.; Hansen-Romu, S.; Mammei, R.; Martin, J.W. [University of Winnipeg, Department of Physics, Winnipeg (Canada); Lauss, B. [Paul Scherrer Institute, Laboratory for Particle Physics, Villigen (Switzerland); Lindner, T. [TRIUMF, Vancouver (Canada); University of Winnipeg, Department of Physics, Winnipeg (Canada); Pierre, E. [TRIUMF, Vancouver (Canada); Osaka University, Research Centre for Nuclear Physics, Osaka (Japan)

    2017-01-15

    A {sup 6}Li-glass-based scintillation detector developed for the TRIUMF neutron electric dipole moment experiment was characterized using the ultra-cold neutron source at the Paul Scherrer Institute (PSI). The data acquisition system for this detector was demonstrated to perform well at rejecting backgrounds. An estimate of the absolute efficiency of background rejection of 99.7±0.1% is made. For variable ultra-cold neutron rate (varying from < 1 kHz to approx. 100 kHz per channel) and background rate seen at the Paul Scherrer Institute, we estimate that the absolute detector efficiency is 89.7{sup +1.3}{sub -1.9}%. Finally a comparison with a commercial Cascade detector was performed for a specific setup at the West-2 beamline of the ultra-cold neutron source at PSI. (orig.)

  9. Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

    International Nuclear Information System (INIS)

    Andriashin, A.V.; Devkin, B.V.; Lychagin, A.A.; Minko, J.V.; Mironov, A.N.; Nesterenko, V.S.; Sztaricskai, T.; Petoe, G.; Vasvary, L.

    1986-01-01

    A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra from (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (Auth.)

  10. Time-of-flight spectrometer for the measurement of gamma correlated neutron spectra

    International Nuclear Information System (INIS)

    Andryashin, A.V.; Devlein, B.V.; Lychagin, A.A.; Minko, Y.V.; Mironov, A.N.; Nesterenko, V.S.

    1986-01-01

    A time-of-flight spectrometer for the measurement of gamma correlated neutron spectra form (n,xnγ) reactions is described. The operation and the main parameters are discussed. The resolution in the neutron channel is 2.2 ns/m at the 150 keV neutron energy threshold. A simultaneous measurement of the time-of-flight and amplitude distributions makes it possible to study gamma correlated neutron spectra as well as the prompt gamma spectra in coincidence with selected energy neutrons. In order to test the spectrometer, measurements of the neutron spectrum in coincidence with the 846 keV gamma line of 56 Fe were carried out at an incident neutron energy of 14.1 MeV. (author). 3 figs., 6 refs

  11. EXPERIMENTAL AND MONTE CARLO INVESTIGATIONS OF BCF-12 SMALL‑AREA PLASTIC SCINTILLATION DETECTORS FOR NEUTRON PINHOLE CAMERA.

    Science.gov (United States)

    Bielecki, J; Drozdowicz, K; Dworak, D; Igielski, A; Janik, W; Kulinska, A; Marciniak, L; Scholz, M; Turzanski, M; Wiacek, U; Woznicka, U; Wójcik-Gargula, A

    2017-12-11

    Plastic organic scintillators such as the blue-emitting BCF-12 are versatile and inexpensive tools. Recently, BCF-12 scintillators have been foreseen for investigation of the spatial distribution of neutrons emitted from dense magnetized plasma. For this purpose, small-area (5 mm × 5 mm) detectors based on BCF-12 scintillation rods and Hamamatsu photomultiplier tubes were designed and constructed at the Institute of Nuclear Physics. They will be located inside the neutron pinhole camera of the PF-24 plasma focus device. Two different geometrical layouts and approaches to the construction of the scintillation element were tested. The aim of this work was to determine the efficiency of the detectors. For this purpose, the experimental investigations using a neutron generator and a Pu-Be source were combined with Monte Carlo computations using the Geant4 code. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Performance of 2000CA/LL and 2260XL liquid scintillation spectrometers for low-level tritium and carbon-14 analyses

    International Nuclear Information System (INIS)

    Rozanski, K.; Stichler, W.; Schwarz, P.

    1991-01-01

    The performance of two commercially available liquid scintillation spectrometers for low-level counting of 3 H and 14 C has been investigated. Two models of new technology Tri-Carb spectrometers from the Packard Instrument Company were tested: the 2000CA/LL and 2260XL. The measurements revealed a superior 3 H performance of the 2000CA/LL equipment owing to its substantially higher counting efficiency. Results for 14 C are less conclusive and depend on the configuration of the counting parameters selected. A comparison of three commercially available scintillation cocktails for tritium assay in water samples revealed a superior performance for PicoFluor LLT. (Author)

  13. A quantitative PGNAA study for use in aqueous solution measurements using Am–Be neutron source and BGO scintillation detector

    Energy Technology Data Exchange (ETDEWEB)

    Ghal-Eh, N., E-mail: ghal-eh@du.ac.ir [School of Physics, Damghan University, P.O. Box 36716-41167, Damghan (Iran, Islamic Republic of); Ahmadi, P. [School of Physics, Damghan University, P.O. Box 36716-41167, Damghan (Iran, Islamic Republic of); Doost-Mohammadi, V. [Nuclear Science and Technology Research Center, AEOI, P.O. Box 11365-8486, Tehran (Iran, Islamic Republic of)

    2016-02-01

    A prompt gamma neutron activation analysis (PGNAA) system including an Am–Be neutron source and BGO scintillation detector are used for quantitative analysis of bulk samples. Both Monte Carlo-simulated and experimental data are considered as input data libraries for two different procedures based on neural network and least squares methods. The results confirm the feasibility and precision of the proposed methods.

  14. Polarisation analysis of elastic neutron scattering using a filter spectrometer on a pulsed source

    International Nuclear Information System (INIS)

    Mayers, J.; Williams, W.G.

    1981-05-01

    The experimental and theoretical aspects of the polarisation analysis technique in elastic neutron scattering are described. An outline design is presented for a filter polarisation analysis spectrometer on the Rutherford Laboratory Spallation Neutron Source and estimates made of its expected count rates and resolution. (author)

  15. Experiments at the time-of-flight neutron spectrometer GNEIS in Gatchina

    International Nuclear Information System (INIS)

    Shcherbakov, O.A.

    1990-01-01

    A brief description of the Gatchina neutron time-of-flight spectrometer GNEIS at the 1 GeV proton synchrocyclotron and its main characteristics are given. Some results of the nuclear fission experiments and neutron cross section measurements are presented not only to illustrate the facility performance but to outline the basic directions of the researches as well. 28 refs.; 10 figs

  16. Measurement of fast neutron spectra inside reactors with a Li{sup 6} semiconductor counter spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ajdacic, V S; Lalovic, B I; Petrovic, B P [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1963-12-15

    The possibility of using the Li{sup 6} semiconductor counter spectrometer for measuring fast neutron spectra inside reactors has been investigated in details and some solutions of the difficulties associated with the high interference of thermal neutrons in well-moderated reactors are suggested and checked experimentally (author)

  17. Direct mass measurements of light neutron-rich nuclei using fast recoil spectrometers

    International Nuclear Information System (INIS)

    Vieira, D.J.; Wouters, J.M.

    1987-01-01

    Extensive new mass measurement capabilities have evolved with the development of recoil spectrometers. In the Z = 3 to 9 neutron-rich region alone, 12 neutron-rich nuclei have been determined for the first time by the fast-recoil direct mass measurement method. A recent experiment using the TOFI spectrometer illustrates this technique. A systematic investigation of nuclei that lie along or near the neutron-drip line has provided a valuable first glimpse into the nuclear structure of such nuclei. No evidence for a large single-particle energy gap at N = 14 is observed; however, a change in the two-neutron separation model calculations, and is interpreted in terms of the smaller 1s/sub 1/2/ - 1s/sub 1/2/ interaction compared to that of the 0d/sub 5/2/ - 0d/sub 5/2/ neutron-neutron interaction. 18 refs., 7 figs., 1 tab

  18. Development of the Brazilian national sheet scintillator converter of neutron; Desenvolvimento de uma tela cintiladora nacional conversora de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Andre Luis Nunes

    2008-03-15

    Both the national domain of the technology for the separation of rare earth elements and the large reserves of these minerals in Brazilian territory, motivated the study of national sheets scintillators converter of neutrons, using a granular mixture Gd{sub 2}O{sub 3}-Zn S:Ag. Three methodologies were used for the manufacture of such sheets, namely: deposition done with a compressed-air gun on a sheet of cellulose type CG3460-3M; fusion of granular mixture with EVA in the mixing chamber and deposition of granular mixture on the substrate of EVA. It was used the flux of the order of 4,46 x 10{sup 5} neutrons thermic/cm{sup 2}.s, coming from the channel irradiation, J-9, of the reactor Argonauta/IEN/CNEN and the radiographic film AA-400 Kodak Industrex. The performances of national scintillator neutrons converter sheets were analyzed and the images obtained with the, demonstrated that the methodologies proposed are technically feasible and can contribute to the reduction of cost of this technique for NDA, but which lack optimization is aimed at increasing the number of photons of light to allow its use in neutrongraphies in Real Time (NRTR). (author)

  19. Bismuth- and lithium-loaded plastic scintillators for gamma and neutron detection

    International Nuclear Information System (INIS)

    Cherepy, Nerine J.; Sanner, Robert D.; Beck, Patrick R.; Swanberg, Erik L.; Tillotson, Thomas M.; Payne, Stephen A.; Hurlbut, Charles R.

    2015-01-01

    Transparent plastic scintillators based on polyvinyltoluene (PVT) have been fabricated with high loading of bismuth carboxylates for gamma spectroscopy, and with lithium carboxylates for neutron detection. When activated with a combination of standard fluors, 2,5-diphenyloxazole (PPO) and tetraphenylbutadiene (TPB), gamma light yields with 15 wt% bismuth tripivalate of 5000 Ph/MeV are measured. A PVT plastic formulation including 30 wt% lithium pivalate and 30 wt% PPO offers both pulse shape discrimination, and a neutron capture peak at ~400 keVee. In another configuration, a bismuth-loaded PVT plastic is coated with ZnS( 6 Li) paint, permitting simultaneous gamma and neutron detection via pulse shape discrimination with a figure-of-merit of 3.8, while offering gamma spectroscopy with energy resolution of R(662 keV)=15%

  20. A compact neutron spectrometer for characterizing inertial confinement fusion implosions at OMEGA and the NIF

    Energy Technology Data Exchange (ETDEWEB)

    Zylstra, A. B., E-mail: zylstra@mit.edu; Gatu Johnson, M.; Frenje, J. A.; Séguin, F. H.; Rinderknecht, H. G.; Rosenberg, M. J.; Sio, H. W.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); McCluskey, M.; Mastrosimone, D.; Glebov, V. Yu.; Forrest, C.; Stoeckl, C.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2014-06-15

    A compact spectrometer for measurements of the primary deuterium-tritium neutron spectrum has been designed and implemented on the OMEGA laser facility [T. Boehly et al., Opt. Commun. 133, 495 (1997)]. This instrument uses the recoil spectrometry technique, where neutrons produced in an implosion elastically scatter protons in a plastic foil, which are subsequently detected by a proton spectrometer. This diagnostic is currently capable of measuring the yield to ∼±10% accuracy, and mean neutron energy to ∼±50 keV precision. As these compact spectrometers can be readily placed at several locations around an implosion, effects of residual fuel bulk flows during burn can be measured. Future improvements to reduce the neutron energy uncertainty to ±15−20 keV are discussed, which will enable measurements of fuel velocities to an accuracy of ∼±25−40 km/s.

  1. A compact neutron spectrometer for characterizing inertial confinement fusion implosions at OMEGA and the NIF.

    Science.gov (United States)

    Zylstra, A B; Gatu Johnson, M; Frenje, J A; Séguin, F H; Rinderknecht, H G; Rosenberg, M J; Sio, H W; Li, C K; Petrasso, R D; McCluskey, M; Mastrosimone, D; Glebov, V Yu; Forrest, C; Stoeckl, C; Sangster, T C

    2014-06-01

    A compact spectrometer for measurements of the primary deuterium-tritium neutron spectrum has been designed and implemented on the OMEGA laser facility [T. Boehly et al., Opt. Commun. 133, 495 (1997)]. This instrument uses the recoil spectrometry technique, where neutrons produced in an implosion elastically scatter protons in a plastic foil, which are subsequently detected by a proton spectrometer. This diagnostic is currently capable of measuring the yield to ~±10% accuracy, and mean neutron energy to ~±50 keV precision. As these compact spectrometers can be readily placed at several locations around an implosion, effects of residual fuel bulk flows during burn can be measured. Future improvements to reduce the neutron energy uncertainty to ±15-20 keV are discussed, which will enable measurements of fuel velocities to an accuracy of ~±25-40 km/s.

  2. Neutron guide shielding for the BIFROST spectrometer at ESS

    OpenAIRE

    Mantulnikovs, K.; Bertelsen, M.; Cooper-Jensen, Carsten P.; Lefmann, K.; Klinkby, E. B.

    2016-01-01

    We report on the study of fast-neutron background for the BIFROST spectrometerat ESS. We investigate the effect of background radiation induced by the interaction of fast neutrons from the source with the material of the neutron guide and devise a reasonable fast, thermal/cold neutron shielding solution for the current guide geometry using McStas and MCNPX. We investigate the effectiveness of the steel shielding around the guide by running simulations with three different steel thicknesses. T...

  3. Passive neutron coincidence counting with plastic scintillators for the characterization of radioactive waste drums

    Energy Technology Data Exchange (ETDEWEB)

    Deyglun, C.; Simony, B.; Perot, B.; Carasco, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Saurel, N.; Colas, S. [CEA, DAM, Valduc, F-21120 Is-sur-Tille (France); Collot, J. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Grenoble Alpes, CNRS/IN2P3, Grenoble (France)

    2015-07-01

    The quantification of radioactive material is essential in the fields of safeguards, criticality control of nuclear processes, dismantling of nuclear facilities and components, or radioactive waste characterization. The Nuclear Measurement Laboratory (LMN) of CEA is involved in the development of time-correlated neutron detection techniques using plastic scintillators. Usually, 3He proportional counters are used for passive neutron coincidence counting owing to their high thermal neutron capture efficiency and gamma insensitivity. However, the global {sup 3}He shortage in the past few years has made these detectors extremely expensive. In addition, contrary to {sup 3}He counters for which a few tens of microseconds are needed to thermalize fast neutrons, in view to maximize the {sup 3}He(n,p){sup 3}H capture cross section, plastic scintillators are based on elastic scattering and therefore the light signal is formed within a few nanoseconds, correlated pulses being detected within a few dozen- or hundred nanoseconds. This time span reflects fission particles time of flight, which allows reducing accordingly the duration of the coincidence gate and thus the rate of random coincidences, which may totally blind fission coincidences when using {sup 3}He counters in case of a high (α,n) reaction rate. However, plastic scintillators are very sensitive to gamma rays, requiring the use of a thick metallic shield to reduce the corresponding background. Cross talk between detectors is also a major issue, which consists on the detection of one particle by several detectors due to elastic or inelastic scattering, leading to true but undesired coincidences. Data analysis algorithms are tested to minimize cross-talk in simultaneously activated detectors. The distinction between useful fission coincidences and the correlated background due to cross-talk, (α,n) and induced (n,2n) or (n,n'γ) reactions, is achieved by measuring 3-fold coincidences. The performances of a

  4. Bertram Brockhouse, the Triple-axis Spectrometer, and Neutron Spectroscopy

    Science.gov (United States)

    Neutron Spectroscopy Resources with Additional Information Bertram Brockhouse Courtesy of McMaster was awarded the 1994 Nobel Prize in Physics for his development of neutron spectroscopy. Bert Physicist, Dies, The New York Times, October 16, 2003 1994: Development of Neutron Spectroscopy, Brookhaven

  5. Neutron detector based on Particles of {sup 6}Li glass scintillator dispersed in organic lightguide matrix

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, K.D., E-mail: ianakiev@lanl.gov; Hehlen, M.P.; Swinhoe, M.T.; Favalli, A.; Iliev, M.L.; Lin, T.C.; Bennett, B.L.; Barker, M.T.

    2015-06-01

    Most {sup 3}He replacement neutron detector technologies today have overlapping neutron–gamma pulse-height distributions, which limits their usefulness and performance. Different techniques are used to mitigate this shortcoming, including Pulse Shape Discrimination (PSD) or threshold settings that suppress all gammas as well as much of the neutrons. As a result, count rates are limited and dead times are high when PSD is used, and the detection efficiency for neutron events is reduced due to the high threshold. This is a problem in most applications where the neutron–gamma separation of {sup 3}He detectors had been essential. This challenge is especially severe for neutron coincidence and multiplicity measurements that have numerous conflicting requirements such as high detection efficiency, short die-away time, short dead time, and high stability. {sup 6}Li-glass scintillators have excellent light output and a single peak distribution, but they are difficult to implement because of their gamma sensitivity. The idea of reducing the gamma sensitivity of {sup 6}Li-glass scintillators by embedding small glass particles in an organic light-guide medium was first presented by L.M. Bollinger in the early 60s but, to the best of our knowledge, has never been reduced to practice. We present a proof of principle detector design and experimental data that develop this concept to a large-area neutron detector. This is achieved by using a multi-component optical medium ({sup 6}Li glass particles attached to a glass supporting structure and a mineral oil light guide) which matches the indices of refraction and minimizes the absorption of the 395 nm scintillator light. The detector design comprises a 10 in. long tube with dual end readout with about 3% volume density of {sup 6}Li glass particles installed. The presented experimental data with various neutron and gamma sources show the desired wide gap between the neutron and gamma pulse height distributions, resulting in a

  6. Warhead verification as inverse problem: Applications of neutron spectrum unfolding from organic-scintillator measurements

    Science.gov (United States)

    Lawrence, Chris C.; Febbraro, Michael; Flaska, Marek; Pozzi, Sara A.; Becchetti, F. D.

    2016-08-01

    Verification of future warhead-dismantlement treaties will require detection of certain warhead attributes without the disclosure of sensitive design information, and this presents an unusual measurement challenge. Neutron spectroscopy—commonly eschewed as an ill-posed inverse problem—may hold special advantages for warhead verification by virtue of its insensitivity to certain neutron-source parameters like plutonium isotopics. In this article, we investigate the usefulness of unfolded neutron spectra obtained from organic-scintillator data for verifying a particular treaty-relevant warhead attribute: the presence of high-explosive and neutron-reflecting materials. Toward this end, several improvements on current unfolding capabilities are demonstrated: deuterated detectors are shown to have superior response-matrix condition to that of standard hydrogen-base scintintillators; a novel data-discretization scheme is proposed which removes important detector nonlinearities; and a technique is described for re-parameterizing the unfolding problem in order to constrain the parameter space of solutions sought, sidestepping the inverse problem altogether. These improvements are demonstrated with trial measurements and verified using accelerator-based time-of-flight calculation of reference spectra. Then, a demonstration is presented in which the elemental compositions of low-Z neutron-attenuating materials are estimated to within 10%. These techniques could have direct application in verifying the presence of high-explosive materials in a neutron-emitting test item, as well as other for treaty verification challenges.

  7. A neutron multiplicity analysis method for uranium samples with liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hao, E-mail: zhouhao_ciae@126.com [China Institute of Atomic Energy, P.O.BOX 275-8, Beijing 102413 (China); Lin, Hongtao [Xi' an Reasearch Institute of High-tech, Xi' an, Shaanxi 710025 (China); Liu, Guorong; Li, Jinghuai; Liang, Qinglei; Zhao, Yonggang [China Institute of Atomic Energy, P.O.BOX 275-8, Beijing 102413 (China)

    2015-10-11

    A new neutron multiplicity analysis method for uranium samples with liquid scintillators is introduced. An active well-type fast neutron multiplicity counter has been built, which consists of four BC501A liquid scintillators, a n/γdiscrimination module MPD-4, a multi-stop time to digital convertor MCS6A, and two Am–Li sources. A mathematical model is built to symbolize the detection processes of fission neutrons. Based on this model, equations in the form of R=F*P*Q*T could be achieved, where F indicates the induced fission rate by interrogation sources, P indicates the transfer matrix determined by multiplication process, Q indicates the transfer matrix determined by detection efficiency, T indicates the transfer matrix determined by signal recording process and crosstalk in the counter. Unknown parameters about the item are determined by the solutions of the equations. A {sup 252}Cf source and some low enriched uranium items have been measured. The feasibility of the method is proven by its application to the data analysis of the experiments.

  8. Eu and Rb co-doped LiCaAlF6 scintillators for neutron detection

    International Nuclear Information System (INIS)

    Yamaji, Akihiro; Yanagida, Takayuki; Kawaguchi, Noriaki; Yokota, Yuui; Fujimoto, Yutaka; Kurosawa, Shunsuke; Pejchal, Jan; Watanabe, Kenichi; Yamazaki, Atsushi; Yoshikawa, Akira

    2013-01-01

    Eu and Rb co-doped LiCaAlF 6 (LiCAF) single crystals with different dopant concentrations were grown by the micro-pulling-down method for neutron detection. Their transmittance spectra showed strong absorption bands at 200–220 and 290–350 nm, and under 241 Am alpha-ray excitation, their radioluminescence spectra exhibited an intense emission peak at 373 nm that was attributed to the Eu 2+ 5d–4f transition. These results were consistent with those for the Rb-free Eu:LiCAF. The highest light yield among the grown crystals was 36,000 ph/n, which was 20% greater than that of the Rb-free crystal. In addition, the neutron-excited scintillation decay times were 650–750 ns slower than that of the Rb-free Eu:LiCAF. -- Highlights: •Eu and Rb co-doped LiCaAlF 6 crystals were grown by the micro-pulling down method. •Transmittance, photoluminescence and radioluminescence spectra were measured. •The light yields and scintillation decays were evaluated under 252 Cf neutron irradiation

  9. The determination of neutron energy spectra of radioisotope sources

    International Nuclear Information System (INIS)

    Lutkin, J.E.

    1975-08-01

    The neutron energy spectrum of a 241 Am-Be radioisotope neutron source has been determined by use of a time of flight neutron spectrometer; this spectrometer not being subject to the same uncertainties as a scintillation spectrometer. Neutron spectra have been determined using a scintillation spectrometer with which the effects of instrumental uncertainties, particularly the pulse shape discrimination have been assessed. In the course of the development of the time flight spectrometer a zero crossover pulse shape discrimination system was developed in order to reduce the unwanted background. Using this system a quantitative survey of pulse shape discrimination with experimental and commercial liquid and plastic organic scintillators were carried out. In addition the pulse shape discrimination properties of inorganic scintillators were also examined. (author)

  10. A new small-angle neutron scattering spectrometer at China Mianyang research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Mei, E-mail: pm740509@163.com; Sun, Liangwei; Chen, Liang; Sun, Guangai; Chen, Bo; Xie, Chaomei; Xia, Qingzhong; Yan, Guanyun; Tian, Qiang; Huang, Chaoqiang; Pang, Beibei; Zhang, Ying; Wang, Yun; Liu, Yaoguang; Kang, Wu; Gong, Jian

    2016-02-21

    A new pinhole small-angle neutron scattering (SANS) spectrometer, installed at the cold neutron source of the 20 MW China Mianyang Research Reactor (CMRR) in the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, has been put into use since 2014. The spectrometer is equipped with a multi-blade mechanical velocity selector, a multi-beam collimation system, and a two-dimensional He-3 position sensitive neutron detector. The q-range of the spectrometer covers from 0.01 nm{sup −1} to 5.0 nm{sup −1}. In this paper, the design and characteristics of the SANS spectrometer are described. The q-resolution calculations, together with calibration measurements of silver behenate and a dispersion of nearly monodisperse poly-methyl-methacrylate nanoparticles indicate that our SANS spectrometer has a good performance and is now in routine service. - Highlights: • A new SANS spectrometer has been put into use since 2014 in China. • One MBR selector possesses a higher resolution compared with traditional selector is used. • The spectrometer has a good performance and is now in routinely service.

  11. Neutron Signal and Noise Separation of the {sup 6}Li-ZnS(Ag) scintillator (BC702) Using Flash ADC

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kye, Y. U. [POSTECH, Pohang (Korea, Republic of); Cho, M. H.; Namkung, W. [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Kim, G. N. [Kyungpook National Univ., Daegu (Korea, Republic of); Lee, M. W. [Dongnam Inst. of radiological and Medical Science, Daejeon (Korea, Republic of)

    2013-10-15

    This study will apply to nuclear data experiments and improve the quality of nuclear data measured at PNF. We also briefly discuss the future plan to apply our research to different kinds of neutron detectors. The parameters to separate the neutron signals and noises of the {sup 6}Li.ZnS(Ag) scintillator are determined through the upper processes. Three kinds of noise are determined by the parameters as shown in figure.5. The signals at the green (pedestal), red (gamma flash), and blue (gamma flash with big signal area) region are subtracted from the total amount of the counted signals. These algorithms will be applied to next neutron TOF experiments. Two additional neutron detectors will be introduced for neutron TOF experiment. These will measure the neutron flux to get the normalization factor. We will also conduct signal and noise separation of these neutron detectors. Neutron total cross-sections have been measured by using the time-of-flight (TOF) method at Pohang Neutron Facility (PNF). A {sup 6}Li.ZnS(Ag) scintillator BC702 from Bicron (Newbury, OH) with a diameter of 127 mm and a thickness of 6.35 mm mounted on an EMI-93090 photomultiplier was used as a detector for the neutron TOF spectrum measurement. This detector is sensitive to thermal and epithermal neutrons and insensitive to gamma radiation. However, it is required to more accurately separate neutron signal and noise. In the present work, we studied neutron signal and noise separation of the BC702 scintillator to measure the accurate neutron TOF data.

  12. Neutron-gamma discrimination employing pattern recognition of the signal from liquid scintillator

    International Nuclear Information System (INIS)

    Kamada, Kohji; Enokido, Uhji; Ogawa, Seiji

    1999-01-01

    A pattern recognition method was applied to the neutron-gamma discrimination of the pulses from the liquid scintillator, NE-213. The circuit for the discrimination is composed of A/D converter, fast SCA, memory control circuit, two digital delay lines and two buffer memories. All components are packed on a small circuit board and are installed into a personal computer. Experiments using a weak 252 Cf n-γ source were undertaken to test the feasibility of the circuit. The circuit is of very easy adjustment and, at the same time, of very economical price when compared with usual discrimination circuits, such as the TAC system

  13. Neutron-gamma discrimination employing pattern recognition of the signal from liquid scintillator

    CERN Document Server

    Kamada, K; Ogawa, S

    1999-01-01

    A pattern recognition method was applied to the neutron-gamma discrimination of the pulses from the liquid scintillator, NE-213. The circuit for the discrimination is composed of A/D converter, fast SCA, memory control circuit, two digital delay lines and two buffer memories. All components are packed on a small circuit board and are installed into a personal computer. Experiments using a weak sup 2 sup 5 sup 2 Cf n-gamma source were undertaken to test the feasibility of the circuit. The circuit is of very easy adjustment and, at the same time, of very economical price when compared with usual discrimination circuits, such as the TAC system.

  14. DETECTORS AND EXPERIMENTAL METHODS: Studies of a scintillator-bar detector for a neutron wall at an external target facility

    Science.gov (United States)

    Yu, Yu-Hong; Xu, Hua-Gen; Xu, Hu-Shan; Zhan, Wen-Long; Sun, Zhi-Yu; Guo, Zhong-Yan; Hu, Zheng-Guo; Wang, Jian-Song; Chen, Jun-Ling; Zheng, Chuan

    2009-07-01

    To achieve a better time resolution of a scintillator-bar detector for a neutron wall at the external target facility of HIRFL-CSR, we have carried out a detailed study of the photomultiplier, the wrapping material and the coupling media. The timing properties of a scintillator-bar detector have been studied in detail with cosmic rays using a high and low level signal coincidence. A time resolution of 80 ps has been achieved in the center of the scintillator-bar detector.

  15. A fan analyzer of neutron beam polarization on the spectrometer REMUR at the pulsed reactor IBR-2

    International Nuclear Information System (INIS)

    Ul'yanov, V.A.; Pusenkov, V.M.; Pleshanov, N.K.

    2004-01-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation at the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multilayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 Angstroem. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (the fan-like polarization analyzer) with a solid angle of polarized neutron detection of 2.2·10 -4 rad. This paper describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of the fan tests on a polarized neutron beam

  16. Superconducting Gamma/Neutron Spectrometer Task 1 Completion Report Evaluation of Candidate Neutron-Sensitive Materials

    CERN Document Server

    Bell, Z W

    2002-01-01

    A review of the scientific literature regarding boron- and lithium-containing compounds was completed. Information such as Debye temperature, heat capacity, superconductivity properties, physical and chemical characteristics, commercial availability, and recipes for synthesis was accumulated and evaluated to develop a list of neutron-sensitive materials likely to perform properly in the spectrometer. The best candidate borides appear to be MgB sub 2 (a superconductor with T sub c = 39 K), B sub 6 Si, B sub 4 C, and elemental boron; all are commercially available. Among the lithium compounds are LiH, LiAl, Li sub 1 sub 2 Si sub 7 , and Li sub 7 Sn sub 2. These materials have or are expected to have high Debye temperatures and sufficiently low heat capacities at 100 mK to produce a useful signal. The responses of sup 1 sup 0 B and sup 6 Li to a fission neutron spectrum were also estimated. These demonstrated that the contribution of scattering events is no more than 3% in a boron-based system and 1.5% in a lith...

  17. Systematic determination of the JET absolute neutron yield using the MPR spectrometer

    International Nuclear Information System (INIS)

    Kronborg-Pettersson, N.

    2003-04-01

    This thesis describes the first high-statistics systematic analysis of JET neutron yield and rate measurements obtained by using data acquired with the Magnetic Proton Recoil (MPR) neutron spectrometer. The neutron yield and rate were determined by using the count-rate from the MPR neutron spectrometer together with neutron profile information from other neutron diagnostic systems. This has previously been done manually for a few pulses. To be able to do this in a more systematic way a part of the neutron spectrum evaluation code was extracted and put into a separate custom-made program and modifications were done to extract sets of MPR data automatically. The codes have been used for analysis of a large set of pulses from the deuterium-tritium campaign at JET in 1997. Several results were obtained, the most significant of which was the clear improvement seen when neutron profile corrections were applied. Neutron yield-rates derived from MPR count-rate are shown to be in excellent agreement with other JET neutron diagnostic data

  18. Systematic determination of the JET absolute neutron yield using the MPR spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kronborg-Pettersson, N

    2003-04-01

    This thesis describes the first high-statistics systematic analysis of JET neutron yield and rate measurements obtained by using data acquired with the Magnetic Proton Recoil (MPR) neutron spectrometer. The neutron yield and rate were determined by using the count-rate from the MPR neutron spectrometer together with neutron profile information from other neutron diagnostic systems. This has previously been done manually for a few pulses. To be able to do this in a more systematic way a part of the neutron spectrum evaluation code was extracted and put into a separate custom-made program and modifications were done to extract sets of MPR data automatically. The codes have been used for analysis of a large set of pulses from the deuterium-tritium campaign at JET in 1997. Several results were obtained, the most significant of which was the clear improvement seen when neutron profile corrections were applied. Neutron yield-rates derived from MPR count-rate are shown to be in excellent agreement with other JET neutron diagnostic data.

  19. Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Andreani, C.; Colognesi, D.; Degiorgi, E.; Filabozzi, A.; Nardone, M.; Pace, E.; Pietropaolo, A.; Senesi, R.

    2003-01-01

    The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH 2 samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing 6 Li-glass neutron detectors and NaI γ detectors revealing the γ-ray cascade from the (n,γ) reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both 6 Li-glass neutron detector and γ detector configurations

  20. Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Andreani, C.; Colognesi, D.; Degiorgi, E.; Filabozzi, A.; Nardone, M.; Pace, E.; Pietropaolo, A.; Senesi, R.

    2003-02-01

    The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH 2 samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing 6Li-glass neutron detectors and NaI γ detectors revealing the γ-ray cascade from the ( n,γ) reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both 6Li-glass neutron detector and γ detector configurations.

  1. Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Andreani, C.; Colognesi, D.; Degiorgi, E.; Filabozzi, A.; Nardone, M.; Pace, E.; Pietropaolo, A. E-mail: antonino.pietropaolo@roma2.infn.it; Senesi, R

    2003-02-01

    The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH{sub 2} samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing {sup 6}Li-glass neutron detectors and NaI {gamma} detectors revealing the {gamma}-ray cascade from the (n,{gamma}) reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both {sup 6}Li-glass neutron detector and {gamma} detector configurations.

  2. Fast neutron tomography with real-time pulse-shape discrimination in organic scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Malcolm J., E-mail: m.joyce@lancaster.ac.uk [Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW (United Kingdom); Agar, Stewart [Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW (United Kingdom); Aspinall, Michael D. [Hybrid Instruments Ltd., Gordon Manley Building, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YW (United Kingdom); Beaumont, Jonathan S.; Colley, Edmund; Colling, Miriam; Dykes, Joseph; Kardasopoulos, Phoevos; Mitton, Katie [Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW (United Kingdom)

    2016-10-21

    A fast neutron tomography system based on the use of real-time pulse-shape discrimination in 7 organic liquid scintillation detectors is described. The system has been tested with a californium-252 source of dose rate 163 μSv/h at 1 m and neutron emission rate of 1.5×10{sup 7} per second into 4π and a maximum acquisition time of 2 h, to characterize two 100×100×100 mm{sup 3} concrete samples. The first of these was a solid sample and the second has a vertical, cylindrical void. The experimental data, supported by simulations with both Monte Carlo methods and MATLAB®, indicate that the presence of the internal cylindrical void, corners and inhomogeneities in the samples can be discerned. The potential for fast neutron assay of this type with the capability to probe hydrogenous features in large low-Z samples is discussed. Neutron tomography of bulk porous samples is achieved that combines effective penetration not possible with thermal neutrons in the absence of beam hardening.

  3. The use of vanadium as a scattering standard for pulsed source neutron spectrometers

    International Nuclear Information System (INIS)

    Mayers, J.

    1983-06-01

    The Gaussian approximation for multiphonon cross-sections has been used in a calculation of the variation of vanadium cross-sections with incident neutron energy. The results show that vanadium behaves as an elastic scatterer to within a few percent on pulsed neutron spectrometers with incident neutron energies up to 1 eV. There is a calculated anisotropy in the scattering of 8%. It is found that the scattering properties of vanadium at 77K and 293K differ by a maximum of 1% except for neutron energies < 15 meV. (author)

  4. 7Li neutron-induced elastic scattering cross section measurement using a slowing-down spectrometer

    Directory of Open Access Journals (Sweden)

    Heusch M.

    2010-10-01

    Full Text Available A new integral measurement of the 7Li neutron induced elastic scattering cross section was determined in a wide neutron energy range. The measurement was performed on the LPSC-PEREN experimental facility using a heterogeneous graphite-LiF slowing-down time spectrometer coupled with an intense pulsed neutron generator (GENEPI-2. This method allows the measurement of the integral elastic scattering cross section in a slowing-down neutron spectrum. A Bayesian approach coupled to Monte Carlo calculations was applied to extract naturalC, 19F and 7Li elastic scattering cross sections.

  5. Response of LET spectrometer based on track etching at some neutron sources

    International Nuclear Information System (INIS)

    Spurny, Frantisek; Brabcova, Katerina; Jadrnickova, Iva

    2008-01-01

    There is still need to develop upgrade, and test further methods able to characterise the external exposure to neutrons. This contribution presents further results obtained with the goal to enlarge and upgrade the possibility of neutron dosimetry and microdosimetry with a LET spectrometer based on the chemically etched track detectors (TED). As TED we have used several types of polyallyldiglycolcarbonates (PADC). The PADC detectors have been exposed in: high energy neutron beams at iThemba facility, Cape Town, South Africa, and in monoenergetic neutron beams at JRC Geel, Belgium. The studies have been performed in the frame of the ESA supported project DOBIES. (author)

  6. Design study of a time-of-flight neutron spectrometer for JT-60U

    International Nuclear Information System (INIS)

    Elevant, T.; Hoek, M.; Nishitani, Takeo.

    1993-06-01

    A time-of-flight neutron spectrometer is proposed for measurements of neutron energy spectra from deuterium-deuterium reactions in JT-60U tokamak plasmas. The sensitivity of the instrument is 2 · 10 -2 cm 2 , energy resolution is 4.5 % (FWHM) and maximum useful count-rate is 6 kHz. Analysis of neutron energy spectra will provide information on central ion temperatures larger than ∼ 4 keV with an accuracy of ± 10 %, and neutron source fraction from reactions between thermal ions with an accuracy of ± 15 %. The minimum time required for data acquisition is 0.1 s. (author)

  7. Modifications of micro-pulling-down method for the growth of selected Li-containing crystals for neutron scintillator and VUV scintillation crystals

    Czech Academy of Sciences Publication Activity Database

    Pejchal, Jan; Fujimoto, Y.; Chani, V.; Yanagida, T.; Yokota, Y.; Yoshikawa, A.; Nikl, Martin; Beitlerová, Alena

    2012-01-01

    Roč. 360, SI (2012), 127–130 ISSN 0022-0248 R&D Projects: GA MŠk(CZ) 1M06002 Grant - others:AVČR(CZ) M100100910 Institutional research plan: CEZ:AV0Z10100521 Keywords : Ti-doping * micro-pulling-down * barium lutetium fluoride * lithium aluminate * neutron scintillator Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.552, year: 2012

  8. Scintillation response of CsI: Tl crystal under neutron, gamma, alpha particles and beta excitations

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceicao Costa; Madi Filho, Tufic; Lopes, Valdir Maciel; Berretta, Jose Roberto; Cardenas, Jose Patricio Nahuel, E-mail: macoper@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Among the converters of X and gamma radiation in light photons, known as scintillators, the one which is the most efficient emits photons with a wavelength near 400 nm. Particularly, among them, the cesium iodine doped with thallium (CsI:Tl) crystal is that which matches better between the light emission spectrum (peak at 540 nm) and the quantum sensitivity curve of the photodiodes and CCD (Charge Coupled Device). This explains the renewed interest in using this crystal as scintillator. Although the CsI:Tl crystal is commercially available, its local development would give the possibility to obtain it in different geometric configurations and coupling. Moreover, there is a special interest in studying new conditions that will alter the properties of this crystal in order to achieve a optimal level of its functional characteristics. Having an efficient national scintillator with low cost is a strategic opportunity to study the response of a detector applied to different types of radiation. The crystal of cesium iodide activated with thallium (CsI:Tl) has a high gamma detection efficiency per unit volume. In this paper, the CsI:Tl crystal, grown by the vertical Bridgman technique in evacuated silica ampoules and with the purpose of use as radiation detectors, is described. To evaluate the scintillator, measures of the thallium distribution in the crystal volume were taken, with overall efficiency score. The scintillator response was studied through gamma radiation from sources of {sup 137}Cs, {sup 60}Co, {sup 22}Na, {sup 54}Mn, {sup 131}I and {sup 99m}Tc; the beta radiation from source of {sup 90}Sr/{sup 90}Y, alpha particles from {sup 241}Am source and the scintillator response to neutrons from Am/Be source. The energetic resolution for {sup 137}Cs gamma rays (662 keV) was 10%. The results showed the validity of using the CsI:Tl crystal developed in our laboratory, in many applications in the area of radiation detectors. (author)

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

    International Nuclear Information System (INIS)

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

    2002-01-01

    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

  10. 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

  11. Measuring the emulsion stability in Cherenkov radiation with insignificant modification of a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Wiechen, A.; Lorenzen, P.Ch.; Reimerdes, E.H.

    1984-01-01

    A method is described by which the stability of emulsions can be measured by a modified liquid scintillation counter. The 226 Ra external standard source of a commercially available equipment, fixed in the measuring position, is used for the production of Cherenkov radiation in a sample of an emulsion. This Cherenkov radiation is absorbed by the sample due to its turbidity. The turbidity of emulsions follows a typical course with time designated as creaming-up-curve. These curves can be registered automatically in digital form. (author)

  12. Q resolution calculation of small angle neutron scattering spectrometer and analysis of form factor

    International Nuclear Information System (INIS)

    Chen Liang; Peng Mei; Wang Yan; Sun Liangwei; Chen Bo

    2011-01-01

    The calculational methods of Small Angle Neutron Scattering (SANS) spectrometer Q resolution function and its correlative Q standard difference were introduced. The effects of Q standard difference were analysed with the geometry lay out of spectrometer and the spread of neutron wavelength. The one dimension Q resolution Gaussian function were analysed. The form factor curve of ideal solid sphere and two different instrument arrangement parameter was convoluted respectively and the different smearing curve of form factor was obtained. The combination of using the Q resolution function to more accurately analysis SANS data. (authors)

  13. A multi-analyzer crystal spectrometer (MAX) for pulsed neutron sources

    International Nuclear Information System (INIS)

    Tajima, K.; Ishikawa, Y.; Kanai, K.; Windsor, C.G.; Tomiyoshi, S.

    1982-03-01

    The paper describes the principle and initial performance of a multi-analyzer crystal spectrometer (MAX) recently installed at the KENS spallation neutron source at Tsukuba. The spectrometer is able to make time of flight scans along a desired direction in reciprocal space, covering a wide range of the energy transfers corresponding to the fifteen analyzer crystals. The constant Q or constant E modes of operation can be performed. The spectrometer is particularly suited for studying collective excitations such as phonons and magnons to high energy transfers using single crystal samples. (author)

  14. The upgraded cold neutron triple-axis spectrometer FLEXX – enhanced capabilities by new instrumental options

    Directory of Open Access Journals (Sweden)

    Habicht Klaus

    2015-01-01

    Full Text Available The upgrade of the cold neutron triple axis spectrometer FLEXX, a work-horse instrument for inelastic neutron scattering matching the sample environment capabilities at Helmholtz-Zentrum Berlin, has been successfully accomplished. Experiments confirmed an order of magnitude gain in flux now allowing for intensity demanding options to be fully exploited at FLEXX. In this article, we describe the layout and design of two newly available FLEXX instrument options in detail. The new Heusler analyzer gives an increase of the detected polarized neutron flux due to its superior focusing properties, significantly improving the feasibility of future polarized and neutron resonance spin echo experiments. The MultiFLEXX option provides simultaneous access to large regions in wavevector and energy space for inelastic excitations thus adding mapping capabilities to the spectrometer.

  15. The new JET 2.5-MeV neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Elevant, T.; Belle, P.v.; Grosshoeg, G.; Hoek, M.; Jarvis, O.N.; Olsson, M.; Sadler, G.

    1992-01-01

    A major upgrade of the JET 2.5-MeV neutron time-of-flight spectrometer has been completed. The improvement has permitted ion temperature measurements for Maxwellian deuterium plasmas with T i >4 keV to be obtained in 0.5-s intervals. By combining observations of neutron and x-ray energy spectra with studies of γ-ray emission from reactions between fast deuterons and impurities, the effects of ICRF heating on the deuterium energy distribution have been studied. The time evolution of neutron energy spectra from deuterium-beam heated deuterium plasmas is illustrated and a method for evaluating the ion temperature from such sequences is indicated. Furthermore, the spectrometer has shown stable performance during high neutron fluxes

  16. Measurements of double differential charged particle emission cross sections and development of a wide range charged particles spectrometer for ten`s MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Nauchi, Yasushi; Baba, Mamoru; Kiyosumi, Takehide [Tohoku Univ., Sendai (Japan). Faculty of Engineering] [and others

    1997-03-01

    We measured (n,xp), (n,xd) cross sections of C and Al for En=64.3 MeV neutrons at the {sup 7}Li(p,n) neutron sources facility at TIARA (Takasaki Establishment, JAERI) by using a conventional SSD-NaI telescope placed in the air. They show characteristic energy and angular dependence in high energy regions. In order to extend the measurements to low energy protons and {alpha} particles, a new spectrometer consisting of low pressure gas counters and BaF{sub 2} scintillators is now under development. A low threshold for low energy {alpha} particles will be achieved by using the gas counters. The particle identification over a wide energy range will be achieved by combining the {Delta}E-E method for low energy particles with the pulse shape discrimination (PSD) method of BaF{sub 2} for high energy particles. (author)

  17. The triple-axis neutron spectrometer KANDI III and measurement of phonons in copper

    International Nuclear Information System (INIS)

    Melamud, M.; Pinto, H.; Shaked, H.

    1976-12-01

    The acoustic phonon dispersion relations of copper were measured using the recently installed triple-axis neutron spectrometer KANDI III. A description of KANDI III and its peripherals is given in this work. The theory of dispersion relations and their measurement using neutron inelastic diffraction are briefly discussed. Raw data and results for copper are presented and compared with the data and results found in the literature

  18. Spectrometry using the PTB neutron multisphere spectrometer (NEMUS) at flight altitudes and at ground level

    CERN Document Server

    Wiegel, B; Matzke, M; Schrewe, U J; Wittstock, J

    2002-01-01

    Bonner sphere measurements are presented for flights at altitudes of up to 12 km and geomagnetic latitudes between 26 deg.N and 86 deg.N and compared with results obtained by several survey meters. As an example of the natural neutron background near sea level, results from a recent longterm measurement campaign performed at the PTB site using an extended spectrometer are presented. The dependence of neutron fluence and ambient dose equivalent on the atmospheric pressure is demonstrated.

  19. Thermal neutron spectra measurements in IEAR-1 Reactor, by using a crystal spectrometer

    International Nuclear Information System (INIS)

    Fulfaro, R.; Figueiredo Neto, A.M.; Stasiulevicius, E.; Vinhas, L.A.

    1975-01-01

    The thermal neutron spectrum of the IEN Argonauta reactor has been measured in the wavelength from 0.7 to 1.9A, using a neutron crystal spectrometer. An aluminium single crystal, in transmission, was used as monochromator. The aluminium crystal reflectivity employed in the analysis of the data was calculated for the first five permitted orders. An effective absorption coefficient of the crystal was used to perform the calculations instead of the macroscopic cross section of the element

  20. High energy resolution characteristics on 14MeV neutron spectrometer for fusion experimental reactor

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, Tetsuo [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.; Takada, Eiji; Nakazawa, Masaharu

    1996-10-01

    A 14MeV neutron spectrometer suitable for an ITER-like fusion experimental reactor is now under development on the basis of a recoil proton counter telescope principle in oblique scattering geometry. To verify its high energy resolution characteristics, preliminary experiments are made for a prototypical detector system. The comparison results show reasonably good agreement and demonstrate the possibility of energy resolution of 2.5% in full width at half maximum for 14MeV neutron spectrometry. (author)

  1. Measuring the absolute DT neutron yield using the Magnetic Recoil Spectrometer at OMEGA and the NIF

    Energy Technology Data Exchange (ETDEWEB)

    Mackinnon, A; Casey, D; Frenje, J A; Johnson, M G; Seguin, F H; Li, C K; Petrasso, R D; Glebov, V Y; Katz, J; Knauer, J; Meyerhofer, D; Sangster, T; Bionta, R; Bleuel, D; Hachett, S P; Hartouni, E; Lepape, S; Mckernan, M; Moran, M; Yeamans, C

    2012-05-03

    A Magnetic Recoil Spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion (ICF) implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

  2. First results of Minimum Fisher Regularisation as unfolding method for JET NE213 liquid scintillator neutron spectrometry

    International Nuclear Information System (INIS)

    Mlynar, Jan; Adams, John M.; Bertalot, Luciano; Conroy, Sean

    2005-01-01

    At JET, the NE213 liquid scintillator is being validated as a diagnostic tool for spectral measurements of neutrons emitted from the plasma. Neutron spectra have to be unfolded from the measured pulse-height spectra, which is an ill-conditioned problem. Therefore, use of two independent unfolding methods allows for less ambiguity on the interpretation of the data. In parallel to the routine algorithm MAXED based on the Maximum Entropy method, the Minimum Fisher Regularisation (MFR) method has been introduced at JET. The MFR method, known from two-dimensional tomography applications, has proved to provide a new transparent tool to validate the JET neutron spectra measured with the NE213 liquid scintillators. In this article, the MFR method applicable to spectra unfolding is briefly explained. After a mention of MFR tests on phantom spectra experimental neutron spectra are presented that were obtained by applying MFR to NE213 data in selected JET experiments. The results tend to confirm MAXED observations

  3. Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker

    Directory of Open Access Journals (Sweden)

    Jakubek J.

    2012-10-01

    Full Text Available We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 × 15 × 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile using light-guides. An alternative readout geometry was designed in an effort to increase the fraction of scintillation light detected by the SiPMs. The new prototype uses a larger SiPM array to cover the entire top face of the tile. This paper details the comparative performance of the two prototype designs. A deuterium-tritium (DT fast-neutron source was used to compare the relative light collection efficiency of the two designs. A collimated UV light source was scanned across the detector face to map the uniformity. The new prototype was found to have 9.5 times better light collection efficiency over the original design. Both prototypes exhibit spatial non-uniformity in their response. Methods of correcting this non-uniformity are discussed.

  4. Fusion Power Measurement Using a Combined Neutron Spectrometer-Camera System at ITER

    International Nuclear Information System (INIS)

    Sjoestrand, Henrik; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Johnson, M. Gatu; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Ronchi, E.; Weiszflog, M.; Kaellne, J.

    2008-01-01

    A central task for fusion plasma diagnostics is to measure the 2.5 and 14 MeV neutron emission rate in order to determine the fusion power. A new method for determining the neutron yield has been developed at JET. It makes use of the magnetic proton recoil neutron spectrometer and a neutron camera and provides the neutron yield with small systematic errors. At ITER a similar system could operate if a high-resolution, high-performance neutron spectrometer similar to the MPR was installed. In this paper, we present how such system could be implemented and how well it would perform under different assumption of plasma scenarios and diagnostic capabilities. It is found that the systematic uncertainty for using such a system as an absolute calibration reference is as low as 3% and hence it would be an excellent candidate for the calibration of neutron monitors such as fission chambers. It is also shown that the system could provide a 1 ms time resolved estimation of the neutron rate with a total uncertainty of 5%

  5. Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Groitl, Felix; Kure, Mathias

    2016-01-01

    A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2 theta-segments) each containing five vertically scattering analyzers (energy channels...... to the energy resolution of a standard cTAS. The dispersion relation of the antiferromagnetic excitations in MnF2 has been mapped out by performing constant energy transfer maps. These results show that the tested setup is virtually spurion free. In addition, focusing effects due to (mis...

  6. New perspectives for undoped CaF2 scintillator as a threshold activation neutron detector

    Science.gov (United States)

    Sibczynski, Pawel; Dziedzic, Andrzej; Grodzicki, Krystian; Iwanowska-Hanke, Joanna; Moszyński, Marek; Swiderski, Lukasz; Syntfeld-Każuch, Agnieszka; Wolski, Dariusz; Carrel, Frédérick; Grabowski, Amélie; Hamel, Matthieu; Laine, Frederic; Sari, Adrien; Iovene, Alessandro; Tintori, Carlo; Fontana, Cristiano; Pino, Felix

    2018-01-01

    In this paper we present the prompt photofission neutron detection performance of undoped CaF2 scintillator using Threshold Activation Detection (TAD). The study is carried out in the frame of C-BORD Horizon 2020 project, during which an efficient toolbox for high volume freight non-intrusive inspection (NII) is under development. Technologies for radiation monitoring are the part of the project. Particularly, detection of various radiological threats on country borders plays an important significant role in Homeland Security applications. Detection of illegal transfer of Special Nuclear Material (SNM) - 235U, 233U and 239Pu - is particular due to the potential use for production of nuclear weapon as well as radiological dispersal device (RDD) V known also as a "dirty bomb". This technique relies on activation of 19F nuclei in the scintillator medium by fast neutrons and registration of high-energy β particles and γ-rays from the decay of reaction products. The radiation from SNM is detected after irradiation in order to avoid detector blinding. Despite the low 19F(n,α)16N or 19F(n,p)19O reaction cross-section, the method could be a good solution for detection of shielded nuclear material. Results obtained with the CaF2 detector were compared with the previous study done for BaF2 and 3He detector. These experimental results were obtained using 252Cf source and 9 MeV Varian Linatron M9 linear accelerator (LINAC). Finally, performance of the prompt neutron detection system based on CaF2 will be validated at Rotterdam Seaport during field trails in 2018.

  7. New perspectives for undoped CaF2 scintillator as a threshold activation neutron detector

    Directory of Open Access Journals (Sweden)

    Sibczynski Pawel

    2018-01-01

    Full Text Available In this paper we present the prompt photofission neutron detection performance of undoped CaF2 scintillator using Threshold Activation Detection (TAD. The study is carried out in the frame of C-BORD Horizon 2020 project, during which an efficient toolbox for high volume freight non-intrusive inspection (NII is under development. Technologies for radiation monitoring are the part of the project. Particularly, detection of various radiological threats on country borders plays an important significant role in Homeland Security applications. Detection of illegal transfer of Special Nuclear Material (SNM - 235U, 233U and 239Pu - is particular due to the potential use for production of nuclear weapon as well as radiological dispersal device (RDD V known also as a “dirty bomb”. This technique relies on activation of 19F nuclei in the scintillator medium by fast neutrons and registration of high-energy β particles and γ-rays from the decay of reaction products. The radiation from SNM is detected after irradiation in order to avoid detector blinding. Despite the low 19F(n,α16N or 19F(n,p19O reaction cross-section, the method could be a good solution for detection of shielded nuclear material. Results obtained with the CaF2 detector were compared with the previous study done for BaF2 and 3He detector. These experimental results were obtained using 252Cf source and 9 MeV Varian Linatron M9 linear accelerator (LINAC. Finally, performance of the prompt neutron detection system based on CaF2 will be validated at Rotterdam Seaport during field trails in 2018.

  8. Measurement of the muon-induced neutron yield in liquid scintillator and stainless steel at LNGS with the LVD experiment

    International Nuclear Information System (INIS)

    Persiani, R.; Garbini, M.; Sartorelli, G.; Selvi, M.

    2013-01-01

    We describe the measurement of the muon-induced neutron yield in liquid scintillator and stainless steel (SS) at the Gran Sasso National Laboratory (LNGS), with the LVD experiment. The Large Volume Detector (LVD) is located in Hall A of the LNGS and is made of 1000 t of liquid scintillator and 1000 t of SS. Using an independent measurement to evaluate the background and with the support of a full Monte Carlo simulation based on Geant4, we measured a neutron yield of (2.9±0.6)×10 −4 and (1.5±0.3)×10 −3 in liquid scintillator and in stainless steel, respectively

  9. Combined proton-recoil and neutron time-of-flight spectrometer for 14 MeV neutrons

    International Nuclear Information System (INIS)

    Grosshoeg, G.; Aronsson, D.; Arvidsson, E.; Beimer, K.-H.; Pekkari, L.-O.; Rydz, R.; Sjoestrand, N.G.

    1983-05-01

    The main effort put into this work is the foundation of a reliable physical basis for a 12-16 MeV neutron-spectrometer at JET. The essential problem is the amount of scatterer that can be incorporated without losing resolution. We have found two possible methods, the use of a pure hydrogen scatterer and the use of a polyethylene foil scatterer. The pure hydrogen solution gives a very complicated spectrometer with large detectors. The polyethylene solution is limited by the thickness and the width of the foil. We judge the solution with the polyethylene foil to be the most promising one for a reliable spectrometer. However, a large foil area is needed. This gives a spectrometer design with an annular foil, an annular neutron detection system, and a central proton-detector. An efficiency of 10 - 6 counts/s per n/cm 2 ,s at the foil can be obtained with a resolution in the order of 100 keV for 14 MeV neutrons. Following the General Requirements given in the contract of this work, we concluded that an instrument with the desired properties can be made. The instruments is able to give useful information about the plasma from plasma temperatures of about 5 keV. (Authors)

  10. Measurement of neutron detection efficiency between 22 and 174 MeV using two different kinds of Pb-scintillating fiber sampling calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati, INFN (Italy); Bini, C. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Roma (Italy); Corradi, G.; Curceanu, C. [Laboratori Nazionali di Frascati, INFN (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Ferrari, A. [Fondazione CNAO, Milano (Italy); Fiore, S.; Gauzzi, P. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Giovannella, S.; Happacher, F. [Laboratori Nazionali di Frascati, INFN (Italy); Iliescu, M. [Laboratori Nazionali di Frascati, INFN (Italy); IFIN-HH, Bucharest (Romania); Luca, A.; Martini, M. [Laboratori Nazionali di Frascati, INFN (Italy); Miscetti, S., E-mail: stefano.miscetti@lnf.infn.i [Laboratori Nazionali di Frascati, INFN (Italy); Nguyen, F. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Passeri, A. [INFN Sezione di Roma Tre, Roma (Italy)

    2010-05-21

    We exposed a prototype of the lead-scintillating fiber KLOE calorimeter to neutron beam of 21, 46 and 174 MeV at The Svedberg Laboratory, Uppsala, to study its neutron detection efficiency. This has been found larger than what expected considering the scintillator thickness of the prototype. We show preliminary measurement carried out with a different prototype with a larger lead/fiber ratio, which proves the relevance of passive material to neutron detection efficiency in this kind of calorimeters.

  11. Development of the unfolding procedures in fast neutron scintillation spectrometry; Razvoj unfolding procedura u scintilacionoj spektrometriji brzih neutrona

    Energy Technology Data Exchange (ETDEWEB)

    Marinkovic, P [Elektrotehnicki fakultet, Belgrade (Yugoslavia)

    1988-07-01

    Two unfolding procedures have been developed for obtaining fast neutron spectrum from proton-recoil spectrum assigned for spectrometry with organic scintillators. First is the method of differentiation of proton-recoil spectrum, and the second is the method based on solution of integral equation of Fredholm of first kind. (author)

  12. Basic Design Report of DC-TOF Inelastic Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    So, Ji Yong; Park, Je Geun; Moon, Myung Kook; Cho, Sang Jin; Choi, Yung Hyun; Lee, Chang Hee

    2006-04-15

    We made Basic designs of neutron guide, choppers, and detectors in order to optimize the design parameters of DC-TOF to be built in the HANARO Cold Neutron Guide Hall. In addition, we calculated the expected performance of DC-TOF using Monte Carlo simulations and evaluated the properties of neutron beam. Based on the results we obtained, we have compared the expected performance of the DC-TOF with those of existing instruments overseas. In conclusion, we believe that we will be able to construct the DC-TOF at HANARO as one of the best instruments of its kinds and it will become an invaluable instrument to researchers in the related field.

  13. Computer-controlled neutron time-of-flight spectrometer. Part II

    International Nuclear Information System (INIS)

    Merriman, S.H.

    1979-12-01

    A time-of-flight spectrometer for neutron inelastic scattering research has been interfaced to a PDP-15/30 computer. The computer is used for experimental data acquisition and analysis and for apparatus control. This report was prepared to summarize the functions of the computer and to act as a users' guide to the software system

  14. Simulations of chopper jitter at the LET neutron spectrometer at the ISIS TS2

    DEFF Research Database (Denmark)

    Klenø, Kaspar Hewitt; Lefmann, Kim; Willendrup, Peter Kjær

    2014-01-01

    The effect of uncertainty in chopper phasing (jitter) has been investigated for the high-resolution time-of-flight spectrometer LET at the ISIS second target station. The investigation is carried out using virtual experiments, with the neutron simulation package McStas, where the chopper jitter i...

  15. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Lefmann, Kim; Abrahamsen, Asger Bech

    2006-01-01

    Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator...

  16. Two-dimensional thermometry by using neutron resonance absorption spectrometer DOG

    International Nuclear Information System (INIS)

    Kamiyama, T.; Noda, H.; Kiyanagi, Y.; Ikeda, S.

    2001-01-01

    We applied the neutron resonance absorption spectroscopy to thermometry of a bulk object. The measurement was done by using the neutron resonance absorption spectrometer, DOG, installed at KENS, High Energy Accelerator Research Organization Neutron Source, which enables us to investigate effective temperature of a particular element by analyzing line width of resonance absorption spectrum. The effective temperature becomes consistence with the sample temperature above room temperature. For the analysis we applied the computed tomography method to reconstruct the temperature distribution on the object cross section. The results and the calculated distribution by the heat conducting equation are well agreed on the temperature difference inside the object. (author)

  17. PNPI differential EDM spectrometer and latest results of measurements of the neutron electric dipole moment

    Energy Technology Data Exchange (ETDEWEB)

    Serebrov, A. P., E-mail: serebrov@pnpi.spb.ru; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M. [National Research Center Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation); Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Geltenbort, P.; Ivanov, S. N.; Zimmer, O. [Institut Max von Laue–Paul Langevin (France)

    2015-12-15

    In this work, the double chamber magnetic resonance spectrometer of the Petersburg Nuclear Physics Institute (PNPI) designed to measure the neutron electric dipole moment (EDM) is briefly described. A method for long storage of polarized ultracold neutrons in a resonance space with a superposed electric field collinear to the leading magnetic field is used. The results of the measurements carried out on the ILL reactor (Grenoble, France) are interpreted as the upper limit of the value of neutron EDM vertical bar d{sub n} vertical bar < 5.5 × 10{sup –26}e cm at the 90% confidence level.

  18. Simulation report for neutron guide and spectrometer layout at HANARO

    International Nuclear Information System (INIS)

    Cho, S. J.; Cho, Y. G.; Ryu, J. S.; Seong, B. S.; Lee, C. H.; Shin, J. W.

    2006-01-01

    A project called 'infrastructure construction for cold neutron research and utilization technique development' was launched in KAERI in July 2003, in order to raise a domestic basic science with an international level and elevate a international competitiveness for the bio-, nano- and informatics technology area. At the end of this project, 3 new instruments and 3 instruments to be moved will be installed in the guide hall. In order to accomplish this project until 2008, guide simulation should be performed for an effective use of expensive neutron to meet the requirements such as wavelengths and type of instruments, experimental space, interferences with other instruments

  19. 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.

  20. Cold-neutron multi-chopper spectrometer for MLF, J-PARC

    International Nuclear Information System (INIS)

    Nakajima, Kenji; Kajimoto, Ryoich; Nakamura, Mistutaka; Arai, Masatoshi; Sato, Taku J.; Osakabe, Toyotaka; Matsuda, Masaaki; Metoki, Naoto; Kakurai, Kazuhisa; Itoh, Shinichi

    2005-01-01

    We are planning to construct a cold-neutron multi-chopper spectrometer for a new spallation neutron source at Materials and Life Science Facility (MLF) at J-PARC, which is dedicated to investigation of low energy excitations and quasi-elastic excitations in the field of solid state physics, chemistry, materials science, soft matter science and biomaterial science. The planned spectrometer will be installed at a H 2 -coupled moderator and will be equipped with a pulse-shaping disk-chopper in addition to a monochromating disk-chopper, and realizes both high-energy resolution (ΔE/E i ≥1%) and high-intensity (one order of magnitude higher than the present state-of-the-art chopper spectrometers)

  1. Neutron time-of-flight counters and spectrometers for diagnostics of burning fusion plasmas

    International Nuclear Information System (INIS)

    Elevant, T.; Olsson, M.

    1991-02-01

    Experiment with burning fusion plasmas in tokamaks will place particular requirements on neutron measurements from radiation resistance-, physics-, burn control- and reliability considerations. The possibility to meet these needs by measurements of neutron fluxes and energy spectra by means of time-of-flight techniques are described. Reference counters and spectrometers are proposed and characterized with respect to efficiency, count-rate capabilities, energy resolution and tolerable neutron and γ-radiation background levels. The instruments can be used in a neutron camera and are capable to operate in collimated neutron fluxes up to levels corresponding to full nuclear output power in the next generation of experiments. Energy resolutions of the spectrometers enables determination of ion temperatures from 3 (keV) through analysis of the Doppler broadening. Primarily, the instruments are aimed for studies of 14 (MeV) neutrons produced in (d,t)-plasmas but can, after minor modifications, be used for analysis of 2.45 (MeV) neutrons produced in (d,d)-plasma. (au) (33 refs.)

  2. Fast Neutron Detection Using Pixelated CdZnTe Spectrometers

    Science.gov (United States)

    Streicher, Michael; Goodman, David; Zhu, Yuefeng; Brown, Steven; Kiff, Scott; He, Zhong

    2017-07-01

    Fast neutrons are an important signature of special nuclear materials (SNMs). They have a low natural background rate and readily penetrate high atomic number materials that easily shield gamma-ray signatures. Therefore, they provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the small signals from these recoils. In this paper, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9-keV X-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.

  3. MAXED, a computer code for the deconvolution of multisphere neutron spectrometer data using the maximum entropy method

    International Nuclear Information System (INIS)

    Reginatto, M.; Goldhagen, P.

    1998-06-01

    The problem of analyzing data from a multisphere neutron spectrometer to infer the energy spectrum of the incident neutrons is discussed. The main features of the code MAXED, a computer program developed to apply the maximum entropy principle to the deconvolution (unfolding) of multisphere neutron spectrometer data, are described, and the use of the code is illustrated with an example. A user's guide for the code MAXED is included in an appendix. The code is available from the authors upon request

  4. The spectrometer PERKEO III and the decay of free neutrons; Das Spektrometer PERKEO III und der Zerfall des freien Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Maerkisch, B.M.

    2006-10-18

    The Standard Model of particle physics describes neutron decay with three parameters. In contrast to that, a multitude of observables are accessible experimentally. With precision measurements sensitive tests of the Standard Model are thus possible. The neutron decay spectrometer PERKEO III was designed and built as part of this work. It will replace its predecessor PERKEO II, which has reached its systematical and statistical limits. With the new instrument measurements with continuous and pulsed neutron beams become feasible. This either provides an increase in statistics of up to two orders of magnitude, or eliminates the two major instrument specific sources of systematical corrections. In our first measurement in winter 2006/2007, the available event rate will be used to determine weak magnetism from the electron asymmetry A. Previously, this value was not statistically accessible in neutron decay. Systematics are analyzed with the help of our measurement with PERKEO II. For this measurement PERKEO III will be installed at the neutron guide H113 at the Institute Laue-Langevin, Grenoble. The neutron beam from this guide is characterized and a model is given, which allows the rapid calculation of beam profiles and absolute event rates from such a beam. In preparation of a future neutron decay instrument the reflective properties of two non-magnetic neutron mirrors were measured. (orig.)

  5. Design Principle of A Small Angle Neutron Scattering Spectrometer. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Ashry, A [Dept. of Physics, Faculty of Education, Ain Shams University, Cairo (Egypt)

    1996-03-01

    The design principle of a small angle neutron scattering (SANS) spectrometer is based on producing monochromatic neutron bursts using two phased rotors. The rotors have a number of slots to achieve the highly available intensity of monoenergetic neutrons at the required resolution. The design principle was applied to improve the performance of the pulsed monochromatic double rotor system at ET-RR-1 to operate as SANS spectrometer. It is shown that for rotors having 19 slots each with radius of curvature 96.8 cm, the intensity gain factor is 13. The proposed SANS spectrometer could cover the neutron wavelength range from 2 A{sup {omicron}} up to 6 A{sup {omicron}} through small angles of scattering from 5 x 10{sup -3} rad. to 0.1 rad. i.e, the scattering wavevector transfer between 0.6 A{sup {omicron}-1} and 0.01 A{sup {omicron}-1}. The maximum neutron flux density on the specimen is 5 x 10{sup 5} n cm{sup -2} s{sup -1}. 8 figs.

  6. A neutron spectrometer based on temperature variations in superheated drop compositions

    CERN Document Server

    Apfel, R E

    2002-01-01

    The response of superheated drop detectors (SDDs) to neutron radiation varies in a self-consistent manner with variations in temperature and pressure, making such compositions suitable for neutron spectrometry. The advantage of this approach is that the response functions of candidate materials versus energy as the temperature or pressure is varied are nested and have distinct thresholds, with no thermal neutron response. These characteristics permit unfolding without the uncertainties associated with other spectrometry techniques, where multiple solutions are possible, thus requiring an initial guess of the spectrum. A spectrometer was developed based on the well-established technology for acoustic sensing of bubble events interfaced with a proportional-integral-derivative temperature controller. The active monitor for neutrons, called REMbrandt sup T sup M , was used as the platform for controlling temperature on a SDD probe and for data acquisition, thereby automating the process of measuring the neutron e...

  7. Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

    Directory of Open Access Journals (Sweden)

    Ersez Tunay

    2017-01-01

    Full Text Available The shielding for the neutron high-resolution backscattering spectrometer (EMU located at the OPAL reactor (ANSTO was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

  8. Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

    Science.gov (United States)

    Ersez, Tunay; Esposto, Fernando; Souza, Nicolas R. de

    2017-09-01

    The shielding for the neutron high-resolution backscattering spectrometer (EMU) located at the OPAL reactor (ANSTO) was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

  9. Resolution of the VESUVIO spectrometer for High-energy Inelastic Neutron Scattering experiments

    Science.gov (United States)

    Imberti, S.; Andreani, C.; Garbuio, V.; Gorini, G.; Pietropaolo, A.; Senesi, R.; Tardocchi, M.

    2005-11-01

    New perspectives for epithermal neutron spectroscopy have been opened up as a result of the development of the Resonance Detector and its use on inverse geometry time-of-flight spectrometers at spallation sources. A special application of the Resonance Detector is the Very Low Angle Detector Bank (VLAD) for the VESUVIO spectrometer at ISIS, operating in the angular range 1∘500 meV, a regime so far inaccessible to experimental studies on condensed matter systems. The HINS measurements complement the Deep Inelastic Neutron Scattering (DINS) measurements performed on VESUVIO in the high wavevector q(20 Å-11 eV), where the short-time single-particle dynamics can be sampled. This paper will revise the main components of the resolution for HINS measurements of VESUVIO. Instrument performances and examples of applications for neutron scattering processes at high energy and at low wavevector transfer are discussed.

  10. A multi-detector neutron spectrometer with nearly isotropic response for environmental and workplace monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Ros, J.M., E-mail: jm.gomezros@ciemat.e [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Bedogni, R. [INFN-LNF Frascati National Laboratory-U.F. Fisica Sanitaria, via E. Fermi n. 40, 00044 Frascati (Italy); Moraleda, M.; Delgado, A.; Romero, A. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Esposito, A. [INFN-LNF Frascati National Laboratory-U.F. Fisica Sanitaria, via E. Fermi n. 40, 00044 Frascati (Italy)

    2010-01-21

    This communication describes an improved design for a neutron spectrometer consisting of {sup 6}Li thermoluminescent dosemeters located at selected positions within a single moderating polyethylene sphere. The spatial arrangement of the dosemeters has been designed using the MCNPX Monte Carlo code to calculate the response matrix for 56 log-equidistant energies from 10{sup -9} to 100 MeV, looking for a configuration that permits to obtain a nearly isotropic response for neutrons in the energy range from thermal to 20 MeV. The feasibility of the proposed spectrometer and the isotropy of its response have been evaluated by simulating exposures to different reference and workplace neutron fields. The FRUIT code has been used for unfolding purposes. The results of the simulations as well as the experimental tests confirm the suitability of the prototype for environmental and workplace monitoring applications.

  11. Single-sphere multiple-detector neutron spectrometer. Final report on Phase 1

    International Nuclear Information System (INIS)

    Sinclair, F.; Stern, I.; Hahn, R.W.; Entine, G.

    1987-07-01

    To address the problem of accurate, timely estimates of the neutron spectral flux, researchers are developing a monitoring instrument based on a single moderating sphere with a large number of independent sensors. Such a single-sphere spectrometer would allow easy measurement of quality factors. This is made possible by the recent development of a novel digital sensor which detects radiation induced errors in a dynamic random-access memory. During Phase I of the SBIR program, researchers constructed a first prototype of the single-sphere spectrometer, measured its response in a neutron flux from an isotopic Am-Be source in several geometries, and compared these with the results of Monte Carlo simulations of neutron transport. The preliminary results show that the approach is feasible and relatively straightforward

  12. Tests of the space gamma spectrometer prototype at the JINR experimental facility with different types of neutron generators

    Science.gov (United States)

    Litvak, M. L.; Vostrukhin, A. A.; Golovin, D. V.; Dubasov, P. V.; Zontikov, A. O.; Kozyrev, A. S.; Krylov, A. R.; Krylov, V. A.; Mitrofanov, I. G.; Mokrousov, M. I.; Repkin, A. N.; Timoshenko, G. N.; Udovichenko, K. V.; Shvetsov, V. N.

    2017-07-01

    The results of the tests of the HPGe gamma spectrometer performed with a planetary soil model and different types of pulse neutron generators are presented. All measurements have been performed at the experimental nuclear planetary science facility (Joint Institute for Nuclear Research) for the physical calibration of active gamma and neutron spectrometers. The aim of the study is to model a space experiment on determining the elemental composition of Martian planetary matter by neutron-induced gamma spectroscopy. The advantages and disadvantages of a gas-filled neutron generator in comparison with a vacuum-tube neutron generator are examined.

  13. Pulse Shape Analysis and Discrimination for Silicon-Photomultipliers in Helium-4 Gas Scintillation Neutron Detector

    Science.gov (United States)

    Barker, Cathleen; Zhu, Ting; Rolison, Lucas; Kiff, Scott; Jordan, Kelly; Enqvist, Andreas

    2018-01-01

    Using natural helium (helium-4), the Arktis 180-bar pressurized gas scintillator is capable of detecting and distinguishing fast neutrons and gammas. The detector has a unique design of three optically separated segments in which 12 silicon-photomultiplier (SiPM) pairs are positioned equilaterally across the detector to allow for them to be fully immersed in the helium-4 gas volume; consequently, no additional optical interfaces are necessary. The SiPM signals were amplified, shaped, and readout by an analog board; a 250 MHz, 14-bit digitizer was used to examine the output pulses from each SiPMpair channel. The SiPM over-voltage had to be adjusted in order to reduce pulse clipping and negative overshoot, which was observed for events with high scintillation production. Pulse shaped discrimination (PSD) was conducted by evaluating three different parameters: time over threshold (TOT), pulse amplitude, and pulse integral. In order to differentiate high and low energy events, a 30ns gate window was implemented to group pulses from two SiPM channels or more for the calculation of TOT. It was demonstrated that pulses from a single SiPM channel within the 30ns window corresponded to low-energy gamma events while groups of pulses from two-channels or more were most likely neutron events. Due to gamma pulses having lower pulse amplitude, the percentage of measured gamma also depends on the threshold value in TOT calculations. Similarly, the threshold values were varied for the optimal PSD methods of using pulse amplitude and pulse area parameters. Helium-4 detectors equipped with SiPMs are excellent for in-the-field radiation measurement of nuclear spent fuel casks. With optimized PSD methods, the goal of developing a fuel cask content monitoring and inspection system based on these helium-4 detectors will be achieved.

  14. Study of the response of a lithium yttrium borate scintillator based neutron rem counter by Monte Carlo radiation transport simulations

    Science.gov (United States)

    Sunil, C.; Tyagi, Mohit; Biju, K.; Shanbhag, A. A.; Bandyopadhyay, T.

    2015-12-01

    The scarcity and the high cost of 3He has spurred the use of various detectors for neutron monitoring. A new lithium yttrium borate scintillator developed in BARC has been studied for its use in a neutron rem counter. The scintillator is made of natural lithium and boron, and the yield of reaction products that will generate a signal in a real time detector has been studied by FLUKA Monte Carlo radiation transport code. A 2 cm lead introduced to enhance the gamma rejection shows no appreciable change in the shape of the fluence response or in the yield of reaction products. The fluence response when normalized at the average energy of an Am-Be neutron source shows promise of being used as rem counter.

  15. Study of the response of a lithium yttrium borate scintillator based neutron rem counter by Monte Carlo radiation transport simulations

    Energy Technology Data Exchange (ETDEWEB)

    Sunil, C., E-mail: csunil11@gmail.com [Accelerator Radiation Safety Section, Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tyagi, Mohit [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Biju, K.; Shanbhag, A.A.; Bandyopadhyay, T. [Accelerator Radiation Safety Section, Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2015-12-11

    The scarcity and the high cost of {sup 3}He has spurred the use of various detectors for neutron monitoring. A new lithium yttrium borate scintillator developed in BARC has been studied for its use in a neutron rem counter. The scintillator is made of natural lithium and boron, and the yield of reaction products that will generate a signal in a real time detector has been studied by FLUKA Monte Carlo radiation transport code. A 2 cm lead introduced to enhance the gamma rejection shows no appreciable change in the shape of the fluence response or in the yield of reaction products. The fluence response when normalized at the average energy of an Am–Be neutron source shows promise of being used as rem counter.

  16. Detailed characterisation of the incident neutron beam on the TOSCA spectrometer

    Science.gov (United States)

    Pinna, Roberto S.; Rudić, Svemir; Capstick, Matthew J.; McPhail, David J.; Pooley, Daniel E.; Howells, Gareth D.; Gorini, Giuseppe; Fernandez-Alonso, Felix

    2017-10-01

    We report a detailed characterisation of the incident neutron beam on the TOSCA spectrometer. A bespoke time-of-flight neutron monitor has been designed, constructed and used to perform extensive spatially resolved measurements of the absolute neutron flux and its underlying time structure at the instrument sample position. The obtained data give a quantitative understanding of the current instrument beyond neutronic simulations and provide a baseline in order to assess the performance of the upgraded instrument. At an average proton current-on-target of 153 μA (ISIS Target Station 1; at the time of measurements) we have found that the wavelength-integrated neutron flux (from 0.28 Å to 4.65 Å) at the position of the TOSCA instrument sample (spatially averaged across the 3 × 3cm2 surface centred around (0,0) position) is approximately 1 . 2 × 106 neutrons cm-2s-1, while the whole beam has a homogeneous distribution across the 3 . 0 × 3 . 5cm2 sample surface. The spectra reproduced the well-known shape of the neutrons moderated by the room temperature water moderator and exhibit a neutron flux of 7 . 3 × 105 neutrons cm-2s-1Å-1 at 1 Å.

  17. Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device.

    Science.gov (United States)

    Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A; Garty, Guy; Harken, Andrew; Brenner, David J

    2015-09-11

    A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n) 3 He and D(d,n) 3 He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9 Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima.

  18. Bayesian and maximum entropy methods for fusion diagnostic measurements with compact neutron spectrometers

    International Nuclear Information System (INIS)

    Reginatto, Marcel; Zimbal, Andreas

    2008-01-01

    In applications of neutron spectrometry to fusion diagnostics, it is advantageous to use methods of data analysis which can extract information from the spectrum that is directly related to the parameters of interest that describe the plasma. We present here methods of data analysis which were developed with this goal in mind, and which were applied to spectrometric measurements made with an organic liquid scintillation detector (type NE213). In our approach, we combine Bayesian parameter estimation methods and unfolding methods based on the maximum entropy principle. This two-step method allows us to optimize the analysis of the data depending on the type of information that we want to extract from the measurements. To illustrate these methods, we analyze neutron measurements made at the PTB accelerator under controlled conditions, using accelerator-produced neutron beams. Although the methods have been chosen with a specific application in mind, they are general enough to be useful for many other types of measurements

  19. Use and imaging performance of CMOS flat panel imager with LiF/ZnS(Ag) and Gadox scintillation screens for neutron radiography

    Science.gov (United States)

    Cha, B. K.; kim, J. Y.; Kim, T. J.; Sim, C.; Cho, G.; Lee, D. H.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2011-01-01

    In digital neutron radiography system, a thermal neutron imaging detector based on neutron-sensitive scintillating screens with CMOS(complementary metal oxide semiconductor) flat panel imager is introduced for non-destructive testing (NDT) application. Recently, large area CMOS APS (active-pixel sensor) in conjunction with scintillation films has been widely used in many digital X-ray imaging applications. Instead of typical imaging detectors such as image plates, cooled-CCD cameras and amorphous silicon flat panel detectors in combination with scintillation screens, we tried to apply a scintillator-based CMOS APS to neutron imaging detection systems for high resolution neutron radiography. In this work, two major Gd2O2S:Tb and 6LiF/ZnS:Ag scintillation screens with various thickness were fabricated by a screen printing method. These neutron converter screens consist of a dispersion of Gd2O2S:Tb and 6LiF/ZnS:Ag scintillating particles in acrylic binder. These scintillating screens coupled-CMOS flat panel imager with 25x50mm2 active area and 48μm pixel pitch was used for neutron radiography. Thermal neutron flux with 6x106n/cm2/s was utilized at the NRF facility of HANARO in KAERI. The neutron imaging characterization of the used detector was investigated in terms of relative light output, linearity and spatial resolution in detail. The experimental results of scintillating screen-based CMOS flat panel detectors demonstrate possibility of high sensitive and high spatial resolution imaging in neutron radiography system.

  20. Studies on a modular high-energy photon spectrometer of pure CsI scintillators

    International Nuclear Information System (INIS)

    Kopyto, D.

    1994-04-01

    Aim of the present thesis is the optimization of components for the construction of a high-energy photon spectrometer of pure CsI for the detection of the neutral pseudoscalar mesons π 0 , η, and η' at COSY. These mesons are distinguished by their decay into two γ quanta and can therefore be detected by means of a photon spectrometer. A concept of a 2-arm shower counter of pure CsI is presented. Conclusions on the energy resolution of such a calorimeter shall yield a test module, which is constructed of 5.5 CsI(pure) pyramide trunk, each of which possesses a length of 30 cm and an angular acceptance of 6 .6 . The geometry of the moduls is formed in such a way that its extension to a 2-arm shower counter is possible at any time. Hitherto 14 by teflon foils wrapped up crystals for the test module were tested. Their energy resolution varies at 0.66 MeV between 20 and 25 % FWHM. Furthermore a method was found, which allows to trim the position dependence to the required values. So for the position dependence of a crystal even a value of 1.1 % could be reached. The energy resolution amounted thereby to 22 % FWHM. A measurement of the energy resolution with 20 MeV protons yielded a value of 7 %. For the energy calibration of the single detector elements in a dynamic range between 1 MeV and 12 GeV with low-energy γ sources the charge response function of the photoelectron multiplier to be applied in the test module was determined in dependence on the light intensity. The measurement resulted that the photomultiplier at 40 MeV (related to a CsI(pure) reference crystal with an about twofold so high efficiency of the detectable light in comparison to the long pyramide trunks) deviates by 4 % and at 300 MeV by 38 % from the linear behaviour, while it at 500 MeV shows a deviation of 50 %

  1. Response matrix of a multisphere neutron spectrometer with an 3 He proportional counter

    International Nuclear Information System (INIS)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A.

    2005-01-01

    The response matrix of a Bonner sphere spectrometer was calculated by use of the MCNP code. As thermal neutron counter, the spectrometer has a 3.2 cm-diameter 3 He-filled proportional counter which is located at the center of a set of polyethylene spheres. The response was calculated for 0, 3, 5, 6, 8, 10, 12, and 16 inches-diameter polyethylene spheres for neutrons whose energy goes from 10 -9 to 20 MeV. The response matrix was compared with a set of responses measured with several monoenergetic neutron sources. In this comparison the calculated matrix agrees with the experimental results. The matrix was also compared with the response matrix calculated for the PTB C spectrometer. Even though that calculation was carried out using a detailed model to describe the proportional counter; both matrices do agree, but small differences are observed in the bare case because of the difference in the model used during calculations. Other differences are in some spheres for 14.8 and 20 MeV neutrons, probably due to the differences in the cross sections used during both calculations. (Author) 28 refs., 1 tab., 6 figs

  2. The thin-foil magnetic proton recoil neutron spectrometer MPRu at JET

    International Nuclear Information System (INIS)

    Andersson Sunden, E.; Sjoestrand, H.; Conroy, S.; Ericsson, G.; Gatu Johnson, M.; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Ronchi, E.; Weiszflog, M.; Kaellne, J.; Gorini, G.; Tardocchi, M.; Combo, A.; Cruz, N.; Batista, A.; Pereira, R.; Fortuna, R.; Sousa, J.; Popovichev, S.

    2009-01-01

    Neutrons are produced in fusion energy experiments with both deuterium (D) and deuterium-tritium (DT) plasmas. Neutron spectroscopy is a valuable tool in the study of the underlying fuel ion populations. The magnetic proton recoil neutron spectrometer, originally installed at JET in 1996 for 14-MeV neutron measurements, has been upgraded, with the main aim of improving its signal-to-background ratio (S/B), making measurements of the 2.5-MeV neutron emission in D plasmas possible. The upgrade includes a new focal-plane detector, based on the phoswich technique and consequently less sensitive to background, and a new custom-designed digital data acquisition system based on transient recorder cards. Results from JET show that the upgraded MPRu can measure 2.5-MeV neutrons with S/B=5, an improvement by a factor of 50 compared with the original MPR. S/B of 2.8x10 4 in future DT experiments is estimated. The performance of the MPRu is exemplified with results from recent D plasma operations at JET, concerning both measurements with Ohmic, ion cyclotron resonance (ICRH) and neutral beam injection (NBI) plasma heating, as well as measurements of tritium burn-up neutrons. The upgraded instrument allows for 2.5-MeV neutron emission and deuterium ion temperature measurements in plasmas with low levels of tritium, a feature necessary for the ITER experiment.

  3. Neutron spectrometer for DD/DT burning ratio measurement in fusion experimental reactor

    International Nuclear Information System (INIS)

    Asai, Keisuke; Naoi, Norihiro; Iguchi, Tetsuo; Watanabe, Kenichi; Kawarabayashi, Jun; Nishitani, Takeo

    2006-01-01

    The most feasible fuels for a fusion reactor are D (Deuterium) and T (Tritium). DD and/or DT fusion reaction or nuclear burning reaction provides two kinds of neutrons, DD neutron and DT neutron, respectively. DD/DT burning ratio, which can be estimated by DD/DT neutron ratio in the burning plasma, is essential for burn control, alpha particle emission rate monitoring and tritium fuel cycle estimation. Here we propose a new neutron spectrometer for the absolute DD/DT burning ratio measurement. The system consists of a Proton Recoil Telescope (PRT) and a Time-of-Flight (TOF) technique. We have conducted preliminary experiments with a prototype detector and a DT neutron beam (φ20 mm) at the Fusion Neutronics Source, Japan Atomic Energy Agency (JAEA), to assess its basic performance. The detection efficiency obtained by the experiment is consistent with the calculation results in PRT, and sufficient energy resolution for the DD/DT neutron discrimination has been achieved in PRT and TOF. The validity of the Monte Carlo calculation has also been confirmed by comparing the experimental results with the calculation results. The design consideration of this system for use in ITER (International Thermonuclear Experimental Reactor) has shown that this system is capable of monitoring the line-integrated DD/DT burning ratio for the plasma core line of sight with the required measurement accuracy of 20% in the upper 4 decades of the ITER operation (fusion power: 100 kW-700 MW). (author)

  4. A remotely triggered fast neutron detection instrument based on a plastic organic scintillator

    Science.gov (United States)

    Jones, A. R.; Aspinall, M. D.; Joyce, M. J.

    2018-02-01

    A detector system for the characterization of radiation fields of both fast neutrons and γ rays is described comprising of a gated photomultiplier tube (PMT), an EJ299-33 solid organic scintillator detector, and an external trigger circuit. The objective of this development was to conceive a means by which the PMT in such a system can be actuated remotely during the high-intensity bursts of pulsed γ-ray contamination that can arise during active interrogation procedures. The system is used to detect neutrons and γ rays using established pulse-shape discrimination (PSD) techniques. The gating circuit enables the PMT to be switched off remotely. This is compatible with use during intense radiation transients to avoid saturation and the disruption of the operation of the PMT during the burst. Data are presented in the form of pulse-height spectra and PSD scatter plots for the system triggered with a strobed light source. These confirm that the gain of the system and the throughput for both triggered and un-triggered scenarios are as expected, given the duty cycle of the stimulating radiation. This demonstrates that the triggering function does not perturb the system response of the detector.

  5. Neutron and photon spectrometry with liquid scintillation detectors in mixed fields

    CERN Document Server

    Klein, H

    2002-01-01

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

  6. Ce and Eu-doped LiSrAlF6 scintillators for neutron detectors

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Kawaguchi, Noriaki; Fujimoto, Yutaka; Yokota, Yuui; Yamazaki, Atsushi; Watanabe, Kenichi; Kamada, Kei; Yoshikawa, Akira; Chani, Valery

    2011-01-01

    Ce 1%, Eu 1%, and Eu 2%-doped LiSrAlF 6 (LiSAF) single crystals were grown by the micro-pulling-down method for thermal neutron applications. The crystals were transparent, 2.0 mm in diameter and 20–40 mm in length. Neither visible inclusions nor cracks were observed. Their transmittance spectra were measured. The strong absorption lines were observed at 200, 240, and 300 nm for Ce:LiSAF due to Ce 3+ 4f–5d transition. In Eu:LiSAF, 200 (4f–5d) and 300 (4f–4f) nm absorption lines were detected. The samples demonstrated strong emission peaks at 300 nm (Ce:LiSAF) and 370 nm (Eu:LiSAFs) when they were irradiated with 241 Am α-rays simulating the α-particles from the 6 Li(n, α) reaction. Thermal neutron responses were examined under 252 Cf irradiation. The absolute light yield of Ce, Eu 1%, and Eu 2% crystals were 3400, 18000, and 30000 ph/n, respectively. Main components of the scintillation decay time of Ce, Eu 1%, and Eu 2%-doped LiSAFs were 63, 1293, and 1205 ns.

  7. 4π-spectrometer technique for measurements of secondary neutron average number in nuclear fission by 252Cf neutrons

    International Nuclear Information System (INIS)

    Vasil'ev, Yu.A.; Barashkov, Yu.A.; Golovanov, O.A.; Sidorov, L.V.

    1977-01-01

    A method for determining the average number of secondary neutrons anti ν produced in nuclear fission by the neutrons of the 252 Cf fission spectra by means of a 4π time-of-flight spectrometer is described. Layers of 252 Cf and an isotope studied are placed close to each other; if the isotope layer density is 1 mg/cm 2 probability of its fission is about 10 -5 per one spontaneous fission of californium. Fission fragments of 252 Cf and the isotope investigated have been detected by two surface-barrier counters with an efficiency close to 100%. The layers and the counters are situated in a measuring chamber placed in the center of the 4π time-of-flight spectrometer. The latter is utilized as a neutron counter because of its fast response. The method has been verified by carrying out measurements for 235 U and 239 Pu. A comparison of the experimental and calculated results shows that the method suggested can apply to determine the number of secondary neutrons in fission of isotopes that have not been investigated yet

  8. Neutron-Gamma Pulse Shape Discrimination With Ne-213 Liquid Scintillator By Using Digital Signal Processing Combined With Similarity Method

    International Nuclear Information System (INIS)

    Mardiyanto

    2008-01-01

    Neutron-Gamma Pulse Shape Discrimination with a NE-213 Liquid Scintillator by Using Digital Signal Processing Combined with Similarity Method. Measurement of mixed neutron-gamma radiation is difficult because a nuclear detector is usually sensitive to both radiations. A new attempt of neutron-gamma pulse shape discrimination for a NE-213 liquid scintillator is presented by using digital signal processing combined with an off-line similarity method. The output pulse shapes are digitized with a high speed digital oscilloscope. The n-γ discrimination is done by calculating the index of each pulse shape, which is determined by the similarity method, and then fusing it with its corresponding pulse height. Preliminary results demonstrate good separation of neutron and gamma-ray signals from a NE-213 scintillator with a simple digital system. The results were better than those with a conventional rise time method. Figure of Merit is used to determine the quality of discrimination. The figure of merit of the discrimination using digital signal processing combined with off-line similarity method are 1.9; 1.7; 1.1; 1.1; and 0.8; on the other hand by using conventional method the rise time are 0.9; 0.9; 0.9; 0.7; and 0.4 for the equivalent electron energy of 800; 278; 139; 69; and 30 keV. (author)

  9. A fast, high light output scintillator for gamma ray and neutron detection. Fifth Semi-Annual Report

    International Nuclear Information System (INIS)

    Entine, Gerald; Kanai, S.; Shah, M.S.; Leonard Cirignano, M.S.; Jarek Glodo; Van Loef, Edgar V.

    2003-01-01

    In view of the attractive properties of RbGd2Br7:Ce for gamma-ray and thermal neutron detection, and the lack of larger volume crystals, the goal of the Phase I project was to perform a rigorous investigation of the crystal growth of this exciting material and explore its capabilities for gamma-ray and thermal neutron detection. The Phase I research was very successful. All technical objectives were met and in many cases exceeded expectations. We were able to produce large (>1 cm3) RbGd2Br7:Ce crystals with excellent scintillation properties and demonstrated the possibility to detect thermal neutrons. As far as we are aware, our Phase I experiment was the first to demonstrate thermal neutron detection with RbGd2Br7:Ce. Clearly, the feasibility of the proposed research was adequately proven. The Phase II research builds on the successful results obtained during Phase I. Phase II will initially focus on optimizing the RbGd2Br7:Ce growth process to produce high quality, larger volume RbGd2Br7:Ce crystals. We will continue to use the versatile Bridgman technique. During this process, crystal growth parameters will be adjusted for optimal growth conditions. Our goal is to produce high quality RbGd2Br7:Ce crystals of size 1 inch x 1 inch x 1 inch (∼16 cm3). We will work on packaging aspects that allow efficient light collection and prevent crystal degradation. We will study and measure emission spectra, light yield, scintillation decay, energy and time resolution. The effects of variation in Ce concentration on the scintillation properties of RbGd2Br7:Ce will be examined in detail. Comprehensive gamma-ray spectroscopic and imaging studies will be conducted. Also, optimization of RbGd2Br7:Ce for thermal neutron detection will be addressed. Our initial studies will determine the optimal geometry of the RbGd2Br7:Ce crystals for neutron detection. For thermal neutron detection experiments, we will produce large area, thin samples in order to minimize gamma-ray sensitivity

  10. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    Science.gov (United States)

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  11. Development of new neutron spin echo spectrometer using multi-layer film spin splitter

    International Nuclear Information System (INIS)

    Tasaki, Seiji; Ebisawa, Toru; Hino, Masahiro; Achiwa, Norio

    2001-01-01

    Neutron spin echo spectrometry is a method using neutron Larmor precession motion in magnetic field, for the measurement of velocity change before and after quasi-elastic scattering of neutron by a sample, such as macromolecules, with high accuracy. The neutron spin echo spectrometer is an interferometer in quantum mechanics, which a neutron is arranged with a parallel or an antiparallel state against magnetic field direction. Intensities of neutron interaction with matters are measured by the superposition of the both spin state components. The contrast losses of interference fringes caused from velocity diversion of incident neutrons are protected by spin echo method, in which a phase shift between the parallel and anti-parallel state neutrons is reduced by reversion of the spin state on the way of neutron path. Neutron beam of high intensity can be measured with a high energy resolution. Strong magnetic field is usually needed to introduce the phase shift between the both spin state components. A multi-layer film spin splitter (MSS) is developed for introducing the phase shift instead of the strong magnetic fields. The MSS consists of three layers, non-magnetic mirror of Ni/Ti, gap layer of Ti (∼1 μm), and magnetic mirror of Permalloy/Ge. Surface roughness of the gap layer leads to diversions of the phase shift, because that the fluctuation of thickness of gap layer is proportional to the phase shift. Characteristics of the MSS are tested as follow: (1) reflectivity of polarized neutron, (2) function check of the MSS, (3) uniformity check of the gap layer, (4) evaluation of the gap layer-thickness. (Suetake, M.)

  12. Simulation of optical configurations and signal processing methods in Anger-type neutron-position scintillation detector

    International Nuclear Information System (INIS)

    Roche, C.T.; Strauss, M.G.; Brenner, R.

    1984-01-01

    The spatial linearity and resolution of Anger-type neutron-position scintillation detectors are studied using a semi-empirical model. Detector optics with either an air gap or optical grease between the scintillator and the dispersive light guide are considered. Three signal processing methods which truncate signals from PMT's distant from the scintillation are compared with the linear resistive weighting method. Air gap optics yields a 15% improvement in spatial resolution and 50% reduction in differential and integral nonlinearity relative to grease coupled optics, using linear processing. Using signal truncation instead of linear processing improves the resolution 15-20% for the air gap and 20-30% for the grease coupling case. Thus, the initial discrepancy in the resolution between the two optics nearly vanished, however the linearity of the grease coupled system is still significantly poorer

  13. A neutron spectrometer based on the combination of time-of-flight and Larmor modulation

    International Nuclear Information System (INIS)

    Mulder, F.M.; Kreuger, R.; Grigoriev, S.V.; Kraan, W.H.; Rekveldt, M.Th.; Van Well, A.A.

    1999-01-01

    A study on the feasibility of neutron beam instrumentation that applies Larmor modulation for incoming, and time-of-flight for scattered wavelength determination (or vice versa) is currently under way at IRI. The instrument resulting from this combination can in principle measure quasi elastic and inelastic scattering with a flexible resolution and dynamic range. An important difference with current spectrometers is that there is no selection of neutron wavelengths for either the incoming beam (direct geometry) or scattered beam (inverted geometry). Therefore much of the available flux is used and there is no a priory selection of the energy transfer range and resolution. This instrument will be mainly applicable for quasi-elastic scattering and complex line shapes that are extended over a broad range in energy transfer. Line shapes can be measured directly in Fourier space, which is often advantageous. Due to signal to noise considerations, this instrument will be less suitable for the determination of weak, discrete energy transfer signals. A requirement for the Larmor modulator is that it can work with a white neutron beam. This can be realised for neutrons having a wavelength above ∼ 0.1 nm by use of 'adiabatic resonance π flippers'. This type of instrument may be applied at the future ESS pulsed neutron source in order to complement current spectrometers. (author)

  14. A portable and wide energy range semiconductor-based neutron spectrometer

    International Nuclear Information System (INIS)

    Hoshor, C.B.; Oakes, T.M.; Myers, E.R.; Rogers, B.J.; Currie, J.E.; Young, S.M.; Crow, J.A.; Scott, P.R.; Miller, W.H.; Bellinger, S.L.; Sobering, T.J.; Fronk, R.G.; Shultis, J.K.; McGregor, D.S.; Caruso, A.N.

    2015-01-01

    Hand-held instruments that can be used to passively detect and identify sources of neutron radiation—either bare or obscured by neutron moderating and/or absorbing material(s)—in real time are of interest in a variety of nuclear non-proliferation and health physics applications. Such an instrument must provide a means to high intrinsic detection efficiency and energy-sensitive measurements of free neutron fields, for neutrons ranging from thermal energies to the top end of the evaporation spectrum. To address and overcome the challenges inherent to the aforementioned applications, four solid-state moderating-type neutron spectrometers of varying cost, weight, and complexity have been designed, fabricated, and tested. The motivation of this work is to introduce these novel human-portable instruments by discussing the fundamental theory of their operation, investigating and analyzing the principal considerations for optimal instrument design, and evaluating the capability of each of the four fabricated spectrometers to meet the application needs.

  15. A portable and wide energy range semiconductor-based neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Hoshor, C.B. [Department of Physics, University of Missouri, Kansas City, MO (United States); Oakes, T.M. [Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO (United States); Myers, E.R.; Rogers, B.J.; Currie, J.E.; Young, S.M.; Crow, J.A.; Scott, P.R. [Department of Physics, University of Missouri, Kansas City, MO (United States); Miller, W.H. [Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO (United States); Missouri University Research Reactor, Columbia, MO (United States); Bellinger, S.L. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Sobering, T.J. [Electronics Design Laboratory, Kansas State University, Manhattan, KS (United States); Fronk, R.G.; Shultis, J.K.; McGregor, D.S. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Caruso, A.N., E-mail: carusoan@umkc.edu [Department of Physics, University of Missouri, Kansas City, MO (United States)

    2015-12-11

    Hand-held instruments that can be used to passively detect and identify sources of neutron radiation—either bare or obscured by neutron moderating and/or absorbing material(s)—in real time are of interest in a variety of nuclear non-proliferation and health physics applications. Such an instrument must provide a means to high intrinsic detection efficiency and energy-sensitive measurements of free neutron fields, for neutrons ranging from thermal energies to the top end of the evaporation spectrum. To address and overcome the challenges inherent to the aforementioned applications, four solid-state moderating-type neutron spectrometers of varying cost, weight, and complexity have been designed, fabricated, and tested. The motivation of this work is to introduce these novel human-portable instruments by discussing the fundamental theory of their operation, investigating and analyzing the principal considerations for optimal instrument design, and evaluating the capability of each of the four fabricated spectrometers to meet the application needs.

  16. Development and evaluation of the Combined Ion and Neutron Spectrometer (CINS)

    International Nuclear Information System (INIS)

    Zeitlin, C.; Maurer, R.; Roth, D.; Goldsten, J.; Grey, M.

    2009-01-01

    The Combined Ion and Neutron Spectrometer, CINS, is designed to measure the charged and neutral particles that contribute to the radiation dose and dose equivalent received by humans in spaceflight. As the depth of shielding increases, either onboard a spacecraft or in a surface habitat, the relative contribution of neutrons increases significantly, so that obtaining accurate neutron spectra becomes a critical part of any dosimetric measurements. The spectrometer system consists of high- and medium-energy neutron detectors along with a charged-particle detector telescope based on a standard silicon stack concept. The present version of the design is intended for ground-based use at particle accelerators; future iterations of the design can easily be streamlined to reduce volume, mass, and power consumption to create an instrument package suitable for spaceflight. The detector components have been tested separately using high-energy heavy ion beams at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory and neutron beams at the Radiological Research Accelerator Facility operated by Columbia University. Here, we review the progress made in fabricating the hardware, report the results of several test runs, and discuss the remaining steps necessary to combine the separate components into an integrated system. A custom data acquisition system built for CINS is described in an accompanying article.

  17. The multiple disk chopper neutron time-of-flight spectrometer at NIST

    International Nuclear Information System (INIS)

    Altorfer, F.B.; Cook, J.C.; Copley, J.R.D.

    1995-01-01

    A highly versatile multiple disk chopper neutron time-of-flight spectrometer is being installed at the Cold Neutron Research Facility of the National institute of Standards and Technology. This new instrument will fill an important gap in the portfolio of neutron inelastic scattering spectrometers in North America. It will be used for a wide variety of experiments such as studies of magnetic and vibrational excitations, tunneling spectroscopy, and quasielastic neutron scattering investigations of local and translational diffusion. The instrument uses disk choppers to monochromate and pulse the incident beam, and the energy changes of scattered neutrons are determined from their times-of-flight to a large array of detectors. The disks and the guide have been designed to make the instrument readily adaptable to the specific performance requirements of experimenters. The authors present important aspects of the design, as well as estimated values of the flux at the sample and the energy resolution for elastic scattering. The instrument should be operational in 1996

  18. Improved performances of 36 m small-angle neutron scattering spectrometer BATAN in Serpong Indonesia

    International Nuclear Information System (INIS)

    Putra, Edy Giri Rachman; Bharoto; Santoso, Eddy; Ikram, Abarrul

    2009-01-01

    SMARTer, a 36 m small-angle neutron scattering (SANS) spectrometer owned by the National Nuclear Energy Agency of Indonesia (BATAN) was installed at the Neutron Scattering Laboratory (NSL) in Serpong, Indonesia. Lots of works on replacing, upgrading and improving the control system, experimental methods, data collection and reduction in the last two years have been carried out to optimize the performance of SMARTer. Some standard samples such as silver behenate, monodisperse polystyrene nanoparticle, porous silica and block copolymer PS-PEP film were measured for the inter-laboratory comparison.

  19. Virtual design of the neutron guide for the TOF spectrometer NEAT

    International Nuclear Information System (INIS)

    Izaola, Zunbeltz; Russina, Margarita

    2010-01-01

    We present the results of a virtual design study based on Monte-Carlo neutron ray tracing techniques for the neutron guide of the time of flight (TOF) spectrometer NEAT. We studied several configurations with linearly or elliptically tapered compressors with different degrees of focusing and different guide coatings. The calculations were performed and crosschecked using two software packages which produced similar results. The geometrical arrangement of selected guide components was optimised with the Particle Swarm Optimisation algorithm. The results of the Monte Carlo simulations confirm an expected intensity gain factor of approximately 5, that can be achieved by the optimal configuration.

  20. Virtual design of the neutron guide for the TOF spectrometer NEAT

    Science.gov (United States)

    Izaola, Zunbeltz; Russina, Margarita

    2010-11-01

    We present the results of a virtual design study based on Monte-Carlo neutron ray tracing techniques for the neutron guide of the time of flight (TOF) spectrometer NEAT. We studied several configurations with linearly or elliptically tapered compressors with different degrees of focusing and different guide coatings. The calculations were performed and crosschecked using two software packages which produced similar results. The geometrical arrangement of selected guide components was optimised with the Particle Swarm Optimisation algorithm. The results of the Monte Carlo simulations confirm an expected intensity gain factor of approximately 5, that can be achieved by the optimal configuration.

  1. Design and experimental tests of a novel neutron spin analyzer for wide angle spin echo spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Fouquet, Peter; Farago, Bela; Andersen, Ken H.; Bentley, Phillip M.; Pastrello, Gilles; Sutton, Iain; Thaveron, Eric; Thomas, Frederic [Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France); Moskvin, Evgeny [Helmholtzzentrum Berlin, Glienicker Strasse 100, D-14109 Berlin (Germany); Pappas, Catherine [Helmholtzzentrum Berlin, Glienicker Strasse 100, D-14109 Berlin (Germany); Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

    2009-09-15

    This paper describes the design and experimental tests of a novel neutron spin analyzer optimized for wide angle spin echo spectrometers. The new design is based on nonremanent magnetic supermirrors, which are magnetized by vertical magnetic fields created by NdFeB high field permanent magnets. The solution presented here gives stable performance at moderate costs in contrast to designs invoking remanent supermirrors. In the experimental part of this paper we demonstrate that the new design performs well in terms of polarization, transmission, and that high quality neutron spin echo spectra can be measured.

  2. The very low angle detector for high-energy inelastic neutron scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Senesi, R.; Rhodes, N.J.; Schooneveld, E.M.

    2008-01-01

    The Very Low Angle Detector (VLAD) bank has been installed on the VESUVIO spectrometer at the ISIS spallation neutron source. The new device allows for high-energy inelastic neutron scattering measurements, at energies above 1 eV, maintaining the wave vector transfer lower than 10A -1 . This opens a still unexplored region of the kinematical (q,ω) space, enabling new and challenging experimental investigations in condensed matter. This paper describes the main instrumental features of the VLAD device, including instrument design, detector response, and calibration procedure

  3. The very low angle detector for high-energy inelastic neutron scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Perelli Cippo, E.; Gorini, G.; Tardocchi, M. [Dipartimento di Fisica ' G. Occhialini' , Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Pietropaolo, A. [Dipartimento di Fisica ' G. Occhialini' , CNISM-Universita degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); NAST Center - Nanoscienze-Nanotecnologie-Strumentazione, Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: antonino.pietropaolo@mib.infn.it; Andreani, C.; Senesi, R. [Dipartimento di Fisica and Centro NAST - Nanoscienze-Nanotecnologie-Strumentazione, Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Rhodes, N.J.; Schooneveld, E.M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0QX OX11 (United Kingdom)

    2008-05-01

    The Very Low Angle Detector (VLAD) bank has been installed on the VESUVIO spectrometer at the ISIS spallation neutron source. The new device allows for high-energy inelastic neutron scattering measurements, at energies above 1 eV, maintaining the wave vector transfer lower than 10A{sup -1}. This opens a still unexplored region of the kinematical (q,{omega}) space, enabling new and challenging experimental investigations in condensed matter. This paper describes the main instrumental features of the VLAD device, including instrument design, detector response, and calibration procedure.

  4. The very low angle detector for high-energy inelastic neutron scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Senesi, R.; Rhodes, N. J.; Schooneveld, E. M.

    2008-05-01

    The Very Low Angle Detector (VLAD) bank has been installed on the VESUVIO spectrometer at the ISIS spallation neutron source. The new device allows for high-energy inelastic neutron scattering measurements, at energies above 1 eV, maintaining the wave vector transfer lower than 10Å-1. This opens a still unexplored region of the kinematical (q, ω) space, enabling new and challenging experimental investigations in condensed matter. This paper describes the main instrumental features of the VLAD device, including instrument design, detector response, and calibration procedure.

  5. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    International Nuclear Information System (INIS)

    Bahl, C.R.H.; Lefmann, K.; Abrahamsen, A.B.; Ronnow, H.M.; Saxild, F.; Jensen, T.B.S.; Udby, L.; Andersen, N.H.; Christensen, N.B.; Jakobsen, H.S.; Larsen, T.; Haefliger, P.S.; Streule, S.; Niedermayer, Ch.

    2006-01-01

    Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging mode and the traditional monochromatic focussing mode

  6. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, C.R.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark) and Department of Physics, Technical University of Denmark, DK-2800 Lyngby (Denmark)]. E-mail: christian.bahl@risoe.dk; Lefmann, K. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)]. E-mail: kim.lefmann@risoe.dk; Abrahamsen, A.B. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Ronnow, H.M. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Saxild, F. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Jensen, T.B.S. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Udby, L. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Andersen, N.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Christensen, N.B. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Jakobsen, H.S. [Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Larsen, T. [Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Haefliger, P.S. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Streule, S.; Niedermayer, Ch. [Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

    2006-05-15

    Recently a monochromatic multiple data taking mode has been demonstrated for diffraction experiments using a RITA type cold neutron spectrometer with a multi-bladed analyser and a position-sensitive detector. Here, we show how this mode can be used in combination with a flexible radial collimator to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging mode and the traditional monochromatic focussing mode.

  7. A time-of-flight spectrometer for neutron diffraction under high pressure or at high temperature

    International Nuclear Information System (INIS)

    Roult, G.; Buevoz, J.L.

    1975-01-01

    For high pressure neutron diffraction studies (40 kilobars) the sample is placed in a very thick cell. In order to allow the neutron beam to go through the cell loosing as little intensity as possible, the inner part is kept solid while the external part has some windows facing the incident and reflected beam. The window dimensions are small (a few millimeters wide and a few centimeters long). There are two alternatives: to have the window either in a perpendicular plane or in a plane parallel to the axis. In the first case a fixed wavelength spectrometer can be used but the sample is small and the contribution of the cell to the diffraction pattern is relatively great. In the second case samples can be something like ten times greater and the cell contribution can be eliminated but a fixed wavelength spectrometer cannot be used. Thus the time-of-flight method is very convenient. The second alternative was chosen

  8. Periodic magnetic field as a polarized and focusing thermal neutron spectrometer and monochromator

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, J. T.; Williams, D. L.; Fuller, M. J.; Gary, C. K.; Piestrup, M. A. [Adelphi Technology, Inc., 2003 East Bayshore Rd., Redwood City, California 94063 (United States); Pantell, R. H.; Feinstein, J. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Flocchini, R. G.; Boussoufi, M.; Egbert, H. P.; Kloh, M. D.; Walker, R. B. [Davis McClellan Nuclear Radiation Center, University of California, McClellan, California 95652 (United States)

    2010-01-15

    A novel periodic magnetic field (PMF) optic is shown to act as a prism, lens, and polarizer for neutrons and particles with a magnetic dipole moment. The PMF has a two-dimensional field in the axial direction of neutron propagation. The PMF alternating magnetic field polarity provides strong gradients that cause separation of neutrons by wavelength axially and by spin state transversely. The spin-up neutrons exit the PMF with their magnetic spins aligned parallel to the PMF magnetic field, and are deflected upward and line focus at a fixed vertical height, proportional to the PMF period, at a downstream focal distance that increases with neutron energy. The PMF has no attenuation by absorption or scatter, as with material prisms or crystal monochromators. Embodiments of the PMF include neutron spectrometer or monochromator, and applications include neutron small angle scattering, crystallography, residual stress analysis, cross section measurements, and reflectometry. Presented are theory, experimental results, computer simulation, applications of the PMF, and comparison of its performance to Stern-Gerlach gradient devices and compound material and magnetic refractive prisms.

  9. Periodic magnetic field as a polarized and focusing thermal neutron spectrometer and monochromator.

    Science.gov (United States)

    Cremer, J T; Williams, D L; Fuller, M J; Gary, C K; Piestrup, M A; Pantell, R H; Feinstein, J; Flocchini, R G; Boussoufi, M; Egbert, H P; Kloh, M D; Walker, R B

    2010-01-01

    A novel periodic magnetic field (PMF) optic is shown to act as a prism, lens, and polarizer for neutrons and particles with a magnetic dipole moment. The PMF has a two-dimensional field in the axial direction of neutron propagation. The PMF alternating magnetic field polarity provides strong gradients that cause separation of neutrons by wavelength axially and by spin state transversely. The spin-up neutrons exit the PMF with their magnetic spins aligned parallel to the PMF magnetic field, and are deflected upward and line focus at a fixed vertical height, proportional to the PMF period, at a downstream focal distance that increases with neutron energy. The PMF has no attenuation by absorption or scatter, as with material prisms or crystal monochromators. Embodiments of the PMF include neutron spectrometer or monochromator, and applications include neutron small angle scattering, crystallography, residual stress analysis, cross section measurements, and reflectometry. Presented are theory, experimental results, computer simulation, applications of the PMF, and comparison of its performance to Stern-Gerlach gradient devices and compound material and magnetic refractive prisms.

  10. Relative light yield and temporal response of a stilbene-doped bibenzyl organic scintillator for neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J. A.; Goldblum, B. L., E-mail: bethany@nuc.berkeley.edu; Brickner, N. M.; Daub, B. H.; Kaufman, G. S.; Bibber, K. van; Vujic, J. [Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States); Bernstein, L. A.; Bleuel, D. L.; Caggiano, J. A.; Hatarik, R.; Phillips, T. W.; Zaitseva, N. P. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Wender, S. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-05-21

    The neutron time-of-flight (nTOF) diagnostics used to characterize implosions at the National Ignition Facility (NIF) has necessitated the development of novel scintillators that exhibit a rapid temporal response and high light yield. One such material, a bibenzyl-stilbene mixed single-crystal organic scintillator grown in a 99.5:0.5 ratio in solution, has become the standard scintillator used for nTOF diagnostics at NIF. The prompt fluorescence lifetime and relative light yield as a function of proton energy were determined to calibrate this material as a neutron detector. The temporal evolution of the intensity of the prompt fluorescent response was modeled using first-order reaction kinetics and the prompt fluorescence decay constant was determined to be 2.46 ± 0.01 (fit) ± 0.13 (systematic) ns. The relative response of the bibenzyl-stilbene mixed crystal generated by recoiling protons was measured, and results were analyzed using Birks' relation to quantify the non-radiative quenching of excitation energy in the scintillator.

  11. Optimal shape of a cold-neutron triple-axis spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lefmann, K., E-mail: lefmann@fys.ku.d [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); European Spallation Source, University of Lund, St. Algatan 4, Lund (Sweden); Filges, U. [Laboratory for Development and Methods, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Treue, F. [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); Kirkensgard, J.J.K. [Institute of Nature and Models, Roskilde University (Denmark); Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen (Denmark); Plesner, B. [Institute of Nature and Models, Roskilde University (Denmark); Hansen, K.S. [Institute of Nature and Models, Roskilde University (Denmark); Mid-Greenland High School, Nuuk, Greenland (Denmark); Kleno, K.H. [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); European Spallation Source, University of Lund, St. Algatan 4, Lund (Sweden)

    2011-04-01

    We have performed a McStas optimization of the primary spectrometer for a generic 40 m long, cold-neutron triple-axis spectrometer with a doubly focusing monochromator. The optimal design contains an elliptically focusing guide, a virtual source point before a low-grade PG monochromator, and non-equidistant focusing at the monochromator. The flux at 5 meV shows a gain factor 12 over the 'classical' design with a straight 12x3cm{sup 2}, m=2 guide and a vertically focusing PG monochromator. In addition, the energy resolution was found to be improved. This unexpectedly large design improvement agrees with the Liouville theorem and can be understood as the product of many smaller gain factors, combined with a more optimal utilization of the beam divergence within the guide. Our results may be relevant for a possible upgrade of a number of cold-neutron triple-axis spectrometers-and for a possible triple-axis spectrometer at the European Spallation Source.

  12. DETEC, a Subprogram for Simulation of the Fast-Neutron Detection Process in a Hydro-Carbonous Plastic Scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, B; Aspelund, O

    1966-07-15

    A description is given of the subprogram DETEC, which for energies below 5 MeV simulates the detection process of a fast-neutron within a large cylindrical plastic scintillator. DETEC has been coded in FORTRAN IV, and consists of a subroutine and a BLOCK-DATA subprogram. The latter is in its present form adapted to the dimensions 5 cm diam. x 8 cm of the scintillating materials NE102 and NE102A. The character of DETEC as a subprogram is manifest through the requirement of a main routine for generation of the following input parameters: 1. fast-neutron position; 2. direction; 3. energy; 4. entrance time; 5. input weight (all referred to the detector surface), and 6. the discriminator threshold. When these are provided, the virtues of DETEC are recording of the detected weight and the time elapsed prior to the detection event. The merits of DETEC are finally demonstrated in two typical applications.

  13. DETEC, a Subprogram for Simulation of the Fast-Neutron Detection Process in a Hydro-Carbonous Plastic Scintillator

    International Nuclear Information System (INIS)

    Gustafsson, B.; Aspelund, O.

    1966-07-01

    A description is given of the subprogram DETEC, which for energies below 5 MeV simulates the detection process of a fast-neutron within a large cylindrical plastic scintillator. DETEC has been coded in FORTRAN IV, and consists of a subroutine and a BLOCK-DATA subprogram. The latter is in its present form adapted to the dimensions 5 cm diam. x 8 cm of the scintillating materials NE102 and NE102A. The character of DETEC as a subprogram is manifest through the requirement of a main routine for generation of the following input parameters: 1. fast-neutron position; 2. direction; 3. energy; 4. entrance time; 5. input weight (all referred to the detector surface), and 6. the discriminator threshold. When these are provided, the virtues of DETEC are recording of the detected weight and the time elapsed prior to the detection event. The merits of DETEC are finally demonstrated in two typical applications

  14. Multiple scattering effects in fast neutron polarization experiments using high-pressure helium-xenon gas scintillators as analyzers

    International Nuclear Information System (INIS)

    Tornow, W.; Mertens, G.

    1977-01-01

    In order to study multiple scattering effects both in the gas and particularly in the solid materials of high-pressure gas scintillators, two asymmetry experiments have been performed by scattering of 15.6 MeV polarized neutrons from helium contained in stainless steel vessels of different wall thicknesses. A monte Carlo computer code taking into account the polarization dependence of the differential scattering cross sections has been written to simulate the experiments and to calculate corrections for multiple scattering on helium, xenon and the gas containment materials. Besides the asymmetries for the various scattering processes involved, the code yields time-of-flight spectra of the scattered neutrons and pulse height spectra of the helium recoil nuclei in the gas scintillator. The agreement between experimental results and Monte Carlo calculations is satisfactory. (Auth.)

  15. Synthetic neutron camera and spectrometer in JET based on AFSI-ASCOT simulations

    Science.gov (United States)

    Sirén, P.; Varje, J.; Weisen, H.; Koskela, T.; contributors, JET

    2017-09-01

    The ASCOT Fusion Source Integrator (AFSI) has been used to calculate neutron production rates and spectra corresponding to the JET 19-channel neutron camera (KN3) and the time-of-flight spectrometer (TOFOR) as ideal diagnostics, without detector-related effects. AFSI calculates fusion product distributions in 4D, based on Monte Carlo integration from arbitrary reactant distribution functions. The distribution functions were calculated by the ASCOT Monte Carlo particle orbit following code for thermal, NBI and ICRH particle reactions. Fusion cross-sections were defined based on the Bosch-Hale model and both DD and DT reactions have been included. Neutrons generated by AFSI-ASCOT simulations have already been applied as a neutron source of the Serpent neutron transport code in ITER studies. Additionally, AFSI has been selected to be a main tool as the fusion product generator in the complete analysis calculation chain: ASCOT - AFSI - SERPENT (neutron and gamma transport Monte Carlo code) - APROS (system and power plant modelling code), which encompasses the plasma as an energy source, heat deposition in plant structures as well as cooling and balance-of-plant in DEMO applications and other reactor relevant analyses. This conference paper presents the first results and validation of the AFSI DD fusion model for different auxiliary heating scenarios (NBI, ICRH) with very different fast particle distribution functions. Both calculated quantities (production rates and spectra) have been compared with experimental data from KN3 and synthetic spectrometer data from ControlRoom code. No unexplained differences have been observed. In future work, AFSI will be extended for synthetic gamma diagnostics and additionally, AFSI will be used as part of the neutron transport calculation chain to model real diagnostics instead of ideal synthetic diagnostics for quantitative benchmarking.

  16. Design and construction of a fast (neutron) spectrometer for magnetic confinement fusion studies

    International Nuclear Information System (INIS)

    Lagattu, A.

    1980-09-01

    Neutron emission in conjunction with the 'Tokamak' devices studied in order to carry out controlled fusion is done at present on a short time scale (a few hundred milliseconds). Obtaining spectrometric information on this emission made it necessary to design sufficiently fast equipment to adapt to this situation. The basis of the equipment selected is conventional: NE213 liquid scintillator in conjunction with a fast photomultiplier. A commercialized fast neutron gamma discriminator (approximately 210 5 S -1 ) was used. The data acquisition and processing system was specially made for this occasion. This assembly, so designed and constructed, was tested on a particle accelerator and on the TFR Tokamak. In the best conditions a spectrum of 60 milliseconds was produced. Hence several spectra can be recorded during an experiment. The rejection of gamma radiations by the discriminator exceeds 99% in such conditions [fr

  17. Fast collimated neutron flux measurement using stilbene scintillator and flashy analog-to-digital converter in JT-60U

    International Nuclear Information System (INIS)

    Ishikawa, M.; Itoga, T.; Okuji, T.; Nakhostin, M.; Shinohara, K.; Hayashi, T.; Sukegawa, A.; Baba, M.; Nishitani, T.

    2006-01-01

    A line-integrated neutron emission profile is routinely measured using the radial neutron collimator system in JT-60U tokamak. Stilbene neuron detectors (SNDs), which combine a stilbene organic crystal scintillation detector (SD) with an analog neutron-gamma pulse shape discrimination (PSD) circuit, have been used to measure collimated neutron flux. Although the SND has many advantages as a neutron detector, the maximum count rate is limited up to ∼1x10 5 counts/s due to the analog PSD circuit. To overcome this issue, a digital signal processing system (DSPS) using a flash analog-to-digital converter (Acqiris DC252, 8 GHz, 10 bits) has been developed at Cyclotron and Radioisotope Center in Tohoku University. In this system anode signals from photomultiplier of the SD are directory stored and digitized. Then, the PSD between neutrons and gamma rays is performed using software. The DSPS has been installed in the vertical neutron collimator system in JT-60U and applied to deuterium experiments. It is confirmed that the PSD is sufficiently performed and collimated neutron flux is successfully measured with count rate up to ∼5x10 5 counts/s without the effect of pileup of detected pulses. The performance of the DSPS as a neutron detector, which supersedes the SND, is demonstrated

  18. An in-beam Compton-suppressed Ge spectrometer for nondestructive neutron activation analysis

    International Nuclear Information System (INIS)

    Zaghloul, R.; Abd El-Haleam, A.; Mostafa, M.; Gantner, E.; Ache, H.J.

    1993-04-01

    A high-efficiency compton background suppressed gamma-ray spectrometer by anti-coincidence counting with a NaI(Tl)-shield around a central HPGe-detector for in-beam prompt gamma-ray neutron activation analysis (AC-PGNAA) using a Cf-252 neutron source has been designed and built to provide simultaneous anti-coincidence spectrometry of natural, industrial and environmental samples. The spectrometer consists of a high-purity germanium detector as the main detector and a large volume cylindrical NaI(Tl) detector as a guard detector. The assembly has the ability to measure instantaneously, simultaneously and nondestructively bulk samples up to about 50 cm 3 . Major constituent elements in several rocks and minerals such as H, B, N, Na, Mg, Al, Si, Cl, K, Ca, P, S, Ti, Fe, Sm, Nd, Mn and Gd can be determined, while oxygen cannot be measured due to its small capture cross section (0.27 mb). Several important minor and trace elements such as B, Cd and Hg beside the low residual activity, rare earths and short-lived isotopes could be detected. The sensitivity of the AC-PGNAA technique is limited by the available neutron flux at the target matrix and the neutron absorption cross section of the elements of interest. PGNAA has the advantage to estimate the constituent elements which are difficult to be measured through the delayed gamm-ray measurements such as B, Bi, C, H, P, Tl, Be, Cl and S in industrial and reference materials and those elements which are transformed into other stable isotopes when undergoing neutron capture. The design of the spectrometer assembly, its properties and performance are described

  19. First Results of Minimum Fisher Regularisation as Unfolding Method for JET NE213 Liquid Scintillator Neutron Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Mlynář, Jan; Adams, J. M.; Bertalot, L.; Conroy, S.

    2005-01-01

    Roč. 74, 1-4 (2005), s. 781-786 ISSN 0920-3796. [Symposium on Fusion Technology - SOFT/23rd./. Benátky, 20.9.2004-24.9.2004] Institutional research plan: CEZ:AV0Z20430508 Keywords : Tokamak * fusion * neutron diagnostic * spectrum unfolding * scintillator regularisation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.981, year: 2005 http://soft2004.igi.cnr.it/

  20. Europium and sodium co-doped LiCaAlF.sub.6./sub. scintillator for neutron detection

    Czech Academy of Sciences Publication Activity Database

    Yanagida, T.; Yamaji, A.; Kawaguchi, N.; Fujimoto, Y.; Fukuda, K.; Kurosawa, S.; Yamazaki, A.; Watanabe, K.; Futami, Y.; Yokota, Y.; Uritani, A.; Iguchi, T.; Yoshikawa, A.; Nikl, Martin

    2011-01-01

    Roč. 4, č. 10 (2011), 106401/1-106401/3 ISSN 1882-0778 Grant - others:GA AV ČR(CZ) M100100910 Institutional research plan: CEZ:AV0Z10100521 Keywords : fluoride * single crystal * scintillator * neutron detection * Eu 2+ center Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.013, year: 2011 http://apex.jsap.jp/link?APEX/4/106401/

  1. Growth and radioluminescence of metal elements doped LiCaAlF.sub.6./sub. single crystals for neutron scintillator

    Czech Academy of Sciences Publication Activity Database

    Tanaka, Ch.; Yokota, Y.; Kurosawa, S.; Yamaji, A.; Jarý, Vítězslav; Babin, Vladimir; Pejchal, Jan; Ohashi, Y.; Kamada, K.; Nikl, Martin; Yoshikawa, A.

    2016-01-01

    Roč. 90, Jul (2016), s. 170-173 ISSN 1350-4487. [International Conference on Luminescent Detectors and Transformers of Ionizing Radiation (LUMDETR). Tartu (Estonsko), 20.09.2015-25.09.2015] R&D Projects: GA MŠk(CZ) LH14266 Institutional support: RVO:68378271 Keywords : neutron scintillator * LiCaAlF 6 * Pb2+ * single crystal Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.442, year: 2016

  2. Scintillation Counters

    Science.gov (United States)

    Bell, Zane W.

    Scintillators find wide use in radiation detection as the detecting medium for gamma/X-rays, and charged and neutral particles. Since the first notice in 1895 by Roentgen of the production of light by X-rays on a barium platinocyanide screen, and Thomas Edison's work over the following 2 years resulting in the discovery of calcium tungstate as a superior fluoroscopy screen, much research and experimentation have been undertaken to discover and elucidate the properties of new scintillators. Scintillators with high density and high atomic number are prized for the detection of gamma rays above 1 MeV; lower atomic number, lower-density materials find use for detecting beta particles and heavy charged particles; hydrogenous scintillators find use in fast-neutron detection; and boron-, lithium-, and gadolinium-containing scintillators are used for slow-neutron detection. This chapter provides the practitioner with an overview of the general characteristics of scintillators, including the variation of probability of interaction with density and atomic number, the characteristics of the light pulse, a list and characteristics of commonly available scintillators and their approximate cost, and recommendations regarding the choice of material for a few specific applications. This chapter does not pretend to present an exhaustive list of scintillators and applications.

  3. Discrimination of neutrons and γ-rays in liquid scintillators based of fuzzy c-means clustering

    International Nuclear Information System (INIS)

    Luo Xiaoliang; Liu Guofu; Yang Jun

    2011-01-01

    A novel method based on fuzzy c-means (FCM) clustering for the discrimination of neutrons and γ-rays in liquid scintillators was presented. The neutrons and γ-rays in the environment were firstly acquired by the portable real-time n-γ discriminator and then discriminated using fuzzy c-means clustering and pulse gradient analysis, respectively. By comparing the results with each other, it is shown that the discrimination results of the fuzzy c-means clustering are consistent with those of the pulse gradient analysis. The decrease in uncertainty and the improvement in discrimination performance of the fuzzy c-means clustering were also observed. (authors)

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

    Science.gov (United States)

    Cetiner, Mustafa Sacit

    electric field accelerates and then decelerates the emitted secondary electron beam, the magnetic field steers the beam away from the source and focuses it onto the electron microchannel plate detector. The initial momentum distribution of the electron beam is observed to have profound effect on the electron transport time. Hence, the CEM field spectrometer measurements suffer more from spectral broadening at similar operating parameters. The CEM field spectrometer measurements were obtained with a 210Po alpha source at the Penn State Radiation Science and Engineering Center, University Park, PA. Although the PEM field spectrometer suffers less from electron transport time dispersion, the CEM field spectrometer is more suited for application to neutron depth profiling. The multiple small-diameter apertures used in the PEM field configuration considerably reduces the geometric efficiency of the spectrometer. Most of the neutron depth profiling measurements, where isotropic emission of charged particles is observed, have relatively low count rates; hence, high detection efficiency is essential.

  5. Resolution of the VESUVIO spectrometer for High-energy Inelastic Neutron Scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Imberti, S. [Universita degli Studi di Roma Tre, Dipartimento di Fisica ' E.Amaldi' , Rome (Italy) and CNR-INFM, Rome (Italy)]. E-mail: silvia.imberti@roma2.infn.it; Andreani, C. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Garbuio, V. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Gorini, G. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G.Occhialini' , Milan (Italy); CNR-INFM, Milan (Italy); Pietropaolo, A. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Senesi, R. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica, Roma 60133 (Italy); CNR-INFM, Rome (Italy); Tardocchi, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G.Occhialini' , Milan (Italy); CNR-INFM, Milan (Italy)

    2005-11-01

    New perspectives for epithermal neutron spectroscopy have been opened up as a result of the development of the Resonance Detector and its use on inverse geometry time-of-flight spectrometers at spallation sources. A special application of the Resonance Detector is the Very Low Angle Detector Bank (VLAD) for the VESUVIO spectrometer at ISIS, operating in the angular range 1 deg. <2{theta}<5 deg. This equipment allows High-energy Inelastic Neutron Scattering (HINS) measurements to be performed in the (q,{omega}) kinematical region at low wavevector (q<10A{sup -1}) and high energy (unlimited) transfer -bar {omega}>500meV, a regime so far inaccessible to experimental studies on condensed matter systems. The HINS measurements complement the Deep Inelastic Neutron Scattering (DINS) measurements performed on VESUVIO in the high wavevector q(20A{sup -1}1eV), where the short-time single-particle dynamics can be sampled. This paper will revise the main components of the resolution for HINS measurements of VESUVIO. Instrument performances and examples of applications for neutron scattering processes at high energy and at low wavevector transfer are discussed.

  6. Time-of-flight small-angle scattering spectrometers on pulsed neutron sources

    International Nuclear Information System (INIS)

    Ostanevich, Yu.M.

    1987-01-01

    The operation principles, constructions, advantages and shortcomings of known time-of-flight small angle neutron scattering (TOF SANS) spectrometers built up with pulsed neutron sources are reviewed. The most important characteristics of TOF SANS apparatuses are rather a high luminosity and the possibility for the measurement in an extremely wide range of scattering vector at a single exposure. This is achieved by simultaneous employment of white beam, TOF technique for wave length-scan and the commonly known angle-scan. However, the electronic equipment, data-matching programs, and the measurement procedure, necessary for accurate normalization of experimental data and their transformation into absolute cross-section scale, they all become more complex, as compared with those for SANS apparatuses operating on steady-state neutron sources, where only angle-scan is used

  7. Calculation of background effects on the VESUVIO eV neutron spectrometer

    International Nuclear Information System (INIS)

    Mayers, J

    2011-01-01

    The VESUVIO spectrometer at the ISIS pulsed neutron source measures the momentum distribution n(p) of atoms by 'neutron Compton scattering' (NCS). Measurements of n(p) provide a unique window into the quantum behaviour of atomic nuclei in condensed matter systems. The VESUVIO 6 Li-doped neutron detectors at forward scattering angles were replaced in February 2008 by yttrium aluminium perovskite (YAP)-doped γ-ray detectors. This paper compares the performance of the two detection systems. It is shown that the YAP detectors provide a much superior resolution and general performance, but suffer from a sample-dependent gamma background. This report details how this background can be calculated and data corrected. Calculation is compared with data for two different instrument geometries. Corrected and uncorrected data are also compared for the current instrument geometry. Some indications of how the gamma background can be reduced are also given

  8. Calculation of background effects on the VESUVIO eV neutron spectrometer

    Science.gov (United States)

    Mayers, J.

    2011-01-01

    The VESUVIO spectrometer at the ISIS pulsed neutron source measures the momentum distribution n(p) of atoms by 'neutron Compton scattering' (NCS). Measurements of n(p) provide a unique window into the quantum behaviour of atomic nuclei in condensed matter systems. The VESUVIO 6Li-doped neutron detectors at forward scattering angles were replaced in February 2008 by yttrium aluminium perovskite (YAP)-doped γ-ray detectors. This paper compares the performance of the two detection systems. It is shown that the YAP detectors provide a much superior resolution and general performance, but suffer from a sample-dependent gamma background. This report details how this background can be calculated and data corrected. Calculation is compared with data for two different instrument geometries. Corrected and uncorrected data are also compared for the current instrument geometry. Some indications of how the gamma background can be reduced are also given.

  9. High flux polarized neutrons triple-axis spectrometer: 2T (LLB-Saclay)

    International Nuclear Information System (INIS)

    Bourges, Ph.; Hennion, B.; Sidis, Y.; Boutrouille, Ph.; Baroni, P.

    1999-01-01

    A description of the performance of the newly designed thermal beam triple-axis spectrometer, 2T at LLB (Saclay) is given. The beam tube will be increased to 50 x 120 mm 2 (HxV) before the monochromator. A gain of about a factor 2 on the neutron flux at the monitor position is expected after this operation, scheduled on April/May 1999. Polarized neutrons beam option will be installed on this triple axis. The polarization is obtained using high quality heusler crystals recently grown at ILL. The size of both heusler monochromator and analyzer have been chosen to fully cover the beam size. The monochromator (analyzer) will be equipped with a vertical (horizontal) curvature. The flux of the polarized beam on the detector is then expected to be 5 times better than IN20 at ILL (best existing polarized neutrons triple-axis on thermal beam) with incident energy upto 75 MeV. (author)

  10. Novel discrimination parameters for neutron-gamma discrimination with liquid scintillation detectors using wavelet transform

    International Nuclear Information System (INIS)

    Singh, H.; Singh, S.

    2015-01-01

    It has been observed that the discrimination performance of the wavelet transform method strongly depends on definition of discrimination parameters. These parameters are usually obtained from a combination of scaling functions at different scales, which represents the energy density of the wavelet coefficients. In this paper, the discrete wavelet transform (DWT) at minimum possible values of scale was investigated. Novel pulse shape discrimination parameters have been proposed for neutron and gamma discrimination in a mixed radiation field and tested with modeled pulses. The performance of these parameters was also validated in terms of quality of discrimination using experimental data of mixed events from an AmBe source collected with BC501 liquid scintillation detector. The quality of discrimination was evaluated by calculating a figure of merit (FOM) with all parameters under same experimental and simulation conditions. The FOM obtained with the proposed novel parameters was also compared with the charge comparison method. The proposed parameters exhibit better FOM as compared to the charge comparison method when high levels of noise are present in the data

  11. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    International Nuclear Information System (INIS)

    Bedogni, R.; Gómez-Ros, J.M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

    2012-01-01

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  12. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    Science.gov (United States)

    Bedogni, R.; Gómez-Ros, J. M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

    2012-08-01

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  13. Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); Gomez-Ros, J.M. [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Perez, L. [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); Angelone, M. [ENEA C.R. Frascati, C.P. 65, 00044 Frascati (Italy); Tana, L. [A.O. Universitaria Pisana-Ospedale S. Chiara, Via Bonanno Pisano, Pisa (Italy)

    2012-08-21

    A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

  14. A novel fast-neutron tomography system based on a plastic scintillator array and a compact D–D neutron generator

    International Nuclear Information System (INIS)

    Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

    2016-01-01

    Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1 cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D–T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D–D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2 mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a

  15. Development and performance test of small angle neutron spectrometer at HANARO

    International Nuclear Information System (INIS)

    Han, Young Soo; Seong, Baek Seok; Lee, Chang Hee; Lee, Jeong Soo; Hong, Kwang Pyo; Choi, Byung Hoon; Choi, Young Hyun; Shin, Eun Joo; Park, Kook Nam

    2004-12-01

    The construction of Small Angle Neutron Spectrometer(SANS) at the CN beam port in HANARO was completed and has been opened to users in July 2001. the 2-D PSD (two dimensional position sensitive detector), the NVS (neutron velocity selector), the detector chamber rotation system, the detector horizontal moving system, the stepping motors, the beam shutter and the attenuator were fully tested and installed. The performance test of all the components was also completed. Wavelengths and resolutions of the neutron beam monochromatized by the NVS were calibrated using both the time-of-flight method and the diffraction measurement on standard material, the silver behenate. The relationship between the selector speed U[rpm] and the neutron wavelength λ[A] was obtained as λ[A]=0.11077+107171/U[rpm]. The controllers for the sample environments, the beam shutter and the stepping motors were constructed and its control programs for those controllers were also developed. The Beam test for the SANS has been finished and the characteristics of neutron beam was analyzed. The experimental methods of SANS and its data treatment method were established. The performance test of the HANARO SANS compared with that of foreign SANS's. shows that the HANARO SANS is quite well comparable with foreign SANS facilities

  16. Distinguishing new science from calibration effects in the electron-volt neutron spectrometer VESUVIO at ISIS

    Energy Technology Data Exchange (ETDEWEB)

    Chatzidimitriou-Dreismann, C.A., E-mail: dreismann@chem.tu-berlin.de [Institute of Chemistry (Sekr. C2), Technical University of Berlin, D-10623 Berlin (Germany); Gray, E. MacA., E-mail: e.gray@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane 4111 (Australia); Blach, T.P., E-mail: t.blach@griffith.edu.au [Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane 4111 (Australia)

    2012-06-01

    The 'standard' procedure for calibrating the Vesuvio eV neutron spectrometer at the ISIS neutron source, forming the basis for data analysis over at least the last decade, was recently documented in considerable detail by the instrument's scientists. Additionally, we recently derived analytic expressions of the sensitivity of recoil peak positions with respect to fight-path parameters and presented neutron-proton scattering results that together called into question the validity of the 'standard' calibration. These investigations should contribute significantly to the assessment of the experimental results obtained with Vesuvio. Here we present new results of neutron-deuteron scattering from D{sub 2} in the backscattering angular range ({theta}>90 Degree-Sign ) which are accompanied by a striking energy increase that violates the Impulse Approximation, thus leading unequivocally the following dilemma: (A) either the 'standard' calibration is correct and then the experimental results represent a novel quantum dynamical effect of D which stands in blatant contradiction of conventional theoretical expectations; (B) or the present 'standard' calibration procedure is seriously deficient and leads to artificial outcomes. For Case (A), we allude to the topic of attosecond quantum dynamical phenomena and our recent neutron scattering experiments from H{sub 2} molecules. For Case (B), some suggestions as to how the 'standard' calibration could be considerably improved are made.

  17. Distinguishing new science from calibration effects in the electron-volt neutron spectrometer VESUVIO at ISIS

    Science.gov (United States)

    Chatzidimitriou-Dreismann, C. A.; Gray, E. MacA.; Blach, T. P.

    2012-06-01

    The "standard" procedure for calibrating the Vesuvio eV neutron spectrometer at the ISIS neutron source, forming the basis for data analysis over at least the last decade, was recently documented in considerable detail by the instrument's scientists. Additionally, we recently derived analytic expressions of the sensitivity of recoil peak positions with respect to fight-path parameters and presented neutron-proton scattering results that together called into question the validity of the "standard" calibration. These investigations should contribute significantly to the assessment of the experimental results obtained with Vesuvio. Here we present new results of neutron-deuteron scattering from D2 in the backscattering angular range (θ>90°) which are accompanied by a striking energy increase that violates the Impulse Approximation, thus leading unequivocally the following dilemma: (A) either the "standard" calibration is correct and then the experimental results represent a novel quantum dynamical effect of D which stands in blatant contradiction of conventional theoretical expectations; (B) or the present "standard" calibration procedure is seriously deficient and leads to artificial outcomes. For Case (A), we allude to the topic of attosecond quantum dynamical phenomena and our recent neutron scattering experiments from H2 molecules. For Case (B), some suggestions as to how the "standard" calibration could be considerably improved are made.

  18. Mounting and testing of a 'sandwich' type neutron spectrometer with semiconductor detectors and 6Li

    International Nuclear Information System (INIS)

    Fabro, M.A.

    1973-01-01

    Commercial surface barrier detectors (Si(Au)) were used to construct the spectrometer; the 6 LiF was evaporated by vacuum onto a film of Formvar and afterwards over the surface of one of the detectors, with a 6 LiF thickness of 0,2 μm (50 μg/cm 2 ) and 1,5 μm(400 μg/cm 2 ) respectively. Tests were made with slow neutrons and with neutrons from the reactions D(d,n) 3 He (2,65 MeV) and T(d,n) 4 He (14 MeV). The energy resolution for thermal neutrons was about 200 keV (FWHM) for the sum (E sub(t) + E sub(α)) and about 7 keV (FWHM) for the difference (E sub(t) - E sub(α)) with an evaluated efficiency of 5,5x10 -4 , for the sum. For the 2,65 MeV neutrons, the energy resolution was about 240 keV (FWHM) and an evaluated efficiency of 2,1 x 10 -7 . It was not possible to detect 14 MeV neutrons [pt

  19. Resolution of the VESUVIO spectrometer for High-energy Inelastic Neutron Scattering experiments

    International Nuclear Information System (INIS)

    Imberti, S.; Andreani, C.; Garbuio, V.; Gorini, G.; Pietropaolo, A.; Senesi, R.; Tardocchi, M.

    2005-01-01

    New perspectives for epithermal neutron spectroscopy have been opened up as a result of the development of the Resonance Detector and its use on inverse geometry time-of-flight spectrometers at spallation sources. A special application of the Resonance Detector is the Very Low Angle Detector Bank (VLAD) for the VESUVIO spectrometer at ISIS, operating in the angular range 1 deg. -1 ) and high energy (unlimited) transfer -bar ω>500meV, a regime so far inaccessible to experimental studies on condensed matter systems. The HINS measurements complement the Deep Inelastic Neutron Scattering (DINS) measurements performed on VESUVIO in the high wavevector q(20A -1 -1 ) and high energy transfer (-bar ω>1eV), where the short-time single-particle dynamics can be sampled. This paper will revise the main components of the resolution for HINS measurements of VESUVIO. Instrument performances and examples of applications for neutron scattering processes at high energy and at low wavevector transfer are discussed

  20. The performance of neutron scattering spectrometers at a long-pulse spallation source

    International Nuclear Information System (INIS)

    Pynn, R.

    1995-01-01

    The first conclusion the author wants to draw is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons

  1. Optimized design of the chopper disks and the neutron guide in a disk chopper neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Copley, J.R.D.

    1990-01-01

    We consider important aspects of the performance of a disk chopper neutron time-of-flight spectrometer. The intensity at the sample position, and the contributions of the choppers to the resolution of the instrument, are evaluated as a function of the widths of the slots in the chopper disks and the width of the neutron guide between the disks. We find that there is an optimum choice of the ratios of these widths and that this choice depends on a single parameter which, for elastic scattering, is a simple ratio of distances. When pairs of counter-rotating disks are employed, the widths of the slots can be modified by grossly changing the phase relationship between the members of a chopper pair. If the slot widths are changed, the width of the guide should also be altered in order to maintain the spectrometer in an optimized state. This change in the guide width may be effectively achieved using an arrangement of nested guides. Resolution and intensity calculations demonstrate the important gains which may be realized using this approach. (orig.)

  2. Portable scintillation gamma-spectrometer for field measurement of radioactivity in extensive objects; Portativnyj stsintillyatsionnyj gamma-spektrometr dlya izmereniya radioaktivnosti ob''emnykh sred v polevykh usloviyakh

    Energy Technology Data Exchange (ETDEWEB)

    Besshejko, O. A. [Taras Shevchenko National University of Kyiv, Kyiv (Ukraine); Vishnevskij, I. N.; Denisenko, R. V.; Malyuk, I. A.; Petrosyan, Eh. E. [Institute for Nuclear Research, Kyiv (Ukraine); Karpenko, S. A.; Prijmak, V. N. [Ukrainian Association for Valves Industry, Dnepropetrovsk (Ukraine)

    2011-07-01

    The portable scintillated gamma-spectrometer for field measurement of radioactivity in the volume objects was designed. The crystal CdWO{sub 4} that has weak dependence of light yield from temperature in combination with PMT was applied as the gamma-rays detector. The design of the device provides the possibility for measuring radioactivity of the extensive objects in 4{pi}-geometry without background measurements. In this case the value of the efficiency needed for specific activity calculation in close approximation depends only from crystal geometry and density of measuring object and may be set as the device parameter without efficiency calibration procedure during the operation. The spectrometer does not have an auxiliary radio-active source and connecting cables in the composition. The smartphone operated under Windows Mobile is used as the control module. Bluetooth connection provides data exchange between smartphone and measurement head.

  3. spectrometer

    Directory of Open Access Journals (Sweden)

    J. K. Hedelius

    2016-08-01

    Full Text Available Bruker™ EM27/SUN instruments are commercial mobile solar-viewing near-IR spectrometers. They show promise for expanding the global density of atmospheric column measurements of greenhouse gases and are being marketed for such applications. They have been shown to measure the same variations of atmospheric gases within a day as the high-resolution spectrometers of the Total Carbon Column Observing Network (TCCON. However, there is little known about the long-term precision and uncertainty budgets of EM27/SUN measurements. In this study, which includes a comparison of 186 measurement days spanning 11 months, we note that atmospheric variations of Xgas within a single day are well captured by these low-resolution instruments, but over several months, the measurements drift noticeably. We present comparisons between EM27/SUN instruments and the TCCON using GGG as the retrieval algorithm. In addition, we perform several tests to evaluate the robustness of the performance and determine the largest sources of errors from these spectrometers. We include comparisons of XCO2, XCH4, XCO, and XN2O. Specifically we note EM27/SUN biases for January 2015 of 0.03, 0.75, –0.12, and 2.43 % for XCO2, XCH4, XCO, and XN2O respectively, with 1σ running precisions of 0.08 and 0.06 % for XCO2 and XCH4 from measurements in Pasadena. We also identify significant error caused by nonlinear sensitivity when using an extended spectral range detector used to measure CO and N2O.

  4. Neutron detection and multiplicity counting using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array

    International Nuclear Information System (INIS)

    Miller, M.C.

    1998-03-01

    Neutron detection and multiplicity counting has been investigated using a boron-loaded plastic scintillator/bismuth germanate phoswich detector array. Boron-loaded plastic combines neutron moderation (H) and detection ( 10 B) at the molecular level, thereby physically coupling increasing detection efficiency and decreasing die-away time with detector volume. Both of these characteristics address a fundamental limitation of thermal-neutron multiplicity counters, where 3 He proportional counters are embedded in a polyethylene matrix. Separation of the phoswich response into its plastic scintillator and bismuth germanate components was accomplished on a pulse-by-pulse basis using custom integrator and timing circuits. In addition, a custom time-tag module was used to provide a time for each detector event. Analysis of the combined energy and time event stream was performed by calibrating each detector's response and filtering based on the presence of a simultaneous energy deposition corresponding to the 10 B(n,alpha) reaction products in the plastic scintillator (93 keV ee ) and the accompanying neutron-capture gamma ray in the bismuth germanate (478 keV). Time-correlation analysis was subsequently performed on the filtered event stream to obtain shift-register-type singles and doubles count rates. Proof-of-principle measurements were conducted with a variety of gamma-ray and neutron sources including 137 Cs, 54 Mn, AmLi, and 252 Cf. Results of this study indicate that a neutron-capture probability of ∼10% and a die-away time of ∼10 micros are possible with a 4-detector array with a detector volume of 1600 cm 3 . Simulations were performed that indicate neutron-capture probabilities on the order of 50% and die-away times of less than 4 micros are realistically achievable. While further study will be required for practical application of such a detection system, the results obtained in this investigation are encouraging and may lead to a new class of high

  5. Upgrading of the triple axis neutron spectrometer TKSN-400 installed at Pakistan research reactor-1

    International Nuclear Information System (INIS)

    Bashir, J; Khan, R.T.A.; Khan, M.M.; Iqbal, N.; Waheed, A.; Hussain, A.; Khan, A.U.; Zaman, Q.

    2000-01-01

    The triple axis neutron spectrometer TKSN-400 installed at 10MW Pakistan Research Reactor has been upgraded. The upgrading included the development of a multi-counter assembly, a PC based spectrometer control and data acquisition system. The multi-counter assembly consists of an embankment of 8 pairs of /sup 3/He counter and 40' collimator. This system is more auspicious than the original arrangement because each of the collimator/counter pair is virtually identical, permitting automatic addition of the intensities and consequently a single high resolution profile as obtained with single counter machine. With these modifications, it has now become possible to measure the complete diffraction pattern in about 24 hours. Finally, the results obtained from the latest system are compared with the results reported in literature. (author)

  6. The upgrade of the cold neutron three-axis spectrometer IN12 at the ILL

    Energy Technology Data Exchange (ETDEWEB)

    Schmalzl, K., E-mail: schmalzl@ill.fr [Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at ILL, BP 156, 38042 Grenoble (France); Schmidt, W. [Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at ILL, BP 156, 38042 Grenoble (France); Raymond, S. [Université Grenoble Alpes and CEA Grenoble, INAC MEM, 38054 Grenoble (France); Feilbach, H. [Forschungszentrum Jülich, Peter Grünberg Institut PGI 6, D-52425 Jülich (Germany); Mounier, C. [Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9 (France); Vettard, B. [Université Grenoble Alpes and CEA Grenoble, INAC MEM, 38054 Grenoble (France); Brückel, T. [Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany)

    2016-05-21

    After nearly 40 years of successful operation the cold three-axis spectrometer IN12 at the Institut Laue-Langevin, Grenoble, France, has been relocated to a new position and the primary spectrometer has been upgraded. Latest modern optical components are employed. A new guide in combination with a virtual source concept and a double focusing monochromator guarantee highest flux. With its high unpolarized and polarized neutron flux IN12 allows for demanding experiments. A velocity selector in the guide ensures a clean beam and a very low background. A gain in flux of about an order of magnitude at the sample position has been achieved compared to the previous instrument and IN12's wavelength range now extends far into the warmish region.

  7. PRISMA - a spectrometer for the measurement of coherent excitations on a pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Andreani, C.; Cilloco, F.; Petrillo, C.; Sacchetti, F.; Windsor, C.G.

    1986-04-01

    The measurement of nuclear and magnetic excitation spectra from single crystal samples remains central to condensed matter physics. The requirements in terms of the range and resolution of the scattering vector Q and energy transfer h/2πω are reviewed and typical experiments with a well defined cross-section are chosen. The performance and limitations of existing instruments are reviewed. A design for a new spectrometer, PRISMA, to be installed on the UK spallation neutron source, ISIS, is presented. Its performance for chosen experiments is given in terms of the Q and h/2πω range covered in a single scan, the resolution and the count rate. (author)

  8. Development of gamma-ray-suppression type of small-sized neutron detector based on a 6Li-glass scintillator

    International Nuclear Information System (INIS)

    Matsumoto, T.; Harano, H.; Shimoyama, T.; Kudo, K.; Uritani, A.

    2005-01-01

    A small-sized thermal neutron detector based on a 6 Li-glass scintillator and a plastic optical fiber was developed for measurement of a dose distribution of thermal neutrons in a thermal neutron standard field. A contribution of gamma rays can not be neglected in the neutron measurement with this detector, although the 6 Li-glass scintillator can be distinguishable for the neutrons and the gamma rays by difference of each pulse height. Moreover, to reduce an uncertainty of neutron counts caused by the gamma ray background around a discrimination level, we suggested a gamma-ray-suppression type of small-sized thermal neutron detector with a 6 Li-glass scintillator, a hollow CsI(Tl) scintillator and plastic optical fibers. The detector can reject signals due to the gamma rays with an anti-coincidence method. In the present paper, we evaluated an ability of a gamma-ray suppression of the detector using the EGS4 electron-photon transport Monte-Carlo code with the PRESTA routine. As the results, the sufficient gamma-ray suppression effect was shown. (author)

  9. BUMS--Bonner sphere Unfolding Made Simple an HTML based multisphere neutron spectrometer unfolding package

    CERN Document Server

    Sweezy, J; Veinot, K

    2002-01-01

    A new multisphere neutron spectrometer unfolding package, Bonner sphere Unfolding Made Simple (BUMS) has been developed that uses an HTML interface to simplify data input and code execution for the novice and the advanced user. This new unfolding package combines the unfolding algorithms contained in other popular unfolding codes under one easy to use interface. The interface makes use of web browsing software to provide a graphical user interface to the unfolding algorithms. BUMS integrates the SPUNIT, BON, MAXIET, and SAND-II unfolding algorithms into a single package. This package also includes a library of 14 response matrices, 58 starting spectra, and 24 dose and detector responses. BUMS has several improvements beyond the addition of unfolding algorithms. It has the ability to search for the most appropriate starting spectra. Also, plots of the unfolded neutron spectra are automatically generated. The BUMS package runs via a web server and may be accessed by any computer with access to the Internet at h...

  10. The principle,technology and applications of the neutron triple-axis spectrometer

    International Nuclear Information System (INIS)

    Li Shiliang; Dai Pengcheng

    2011-01-01

    As a subatomic particle, the neutron has unique properties which allow it to play an important and irreplaceable role in many research fields. Based on the principle of momentum and energy conservation, a neutron triple-axis spectrometer (TAS) can measure the elastic and inelastic scattering of a system to obtain structural and dynamical information. The TAS was given its name for its three major parts: the monochromator, sample holder, and analyzer, each of which can rotate independently. Because of the important role that the TAS plays in physics, especially in condensed matter physics, the Institute of Physics of the Chinese Academy of Sciences has decided to collaborate with the China Institute of Atomic Energy to build a modern TAS in the newly-built Chinese Research Reactor. This paper will describe the principle, technology and applications of the TAS. (authors)

  11. The Magnetic Recoil Spectrometer for time-resolved neutron measurements (MRSt) at the NIF

    Science.gov (United States)

    Parker, C. E.; Frenje, J. A.; Wink, C. W.; Gatu Johnson, M.; Lahmann, B.; Li, C. K.; Seguin, F. H.; Petrasso, R. D.; Hilsabeck, T. J.; Kilkenny, J. D.; Bionta, R.; Casey, D. T.; Khater, H. Y.; Forrest, C. J.; Glebov, V. Yu.; Sorce, C.; Hares, J. D.; Siegmund, O. H. W.

    2017-10-01

    The next-generation Magnetic Recoil Spectrometer, called MRSt, will provide time-resolved measurements of the DT-neutron spectrum. These measurements will provide critical information about the time evolution of the fuel assembly, hot-spot formation, and nuclear burn in Inertial Confinement Fusion (ICF) implosions at the National Ignition Facility (NIF). The neutron spectrum in the energy range 12-16 MeV will be measured with high accuracy ( 5%), unprecedented energy resolution ( 100 keV) and, for the first time ever, time resolution ( 20 ps). An overview of the physics motivation, conceptual design for meeting these performance requirements, and the status of the offline tests for critical components will be presented. This work was supported in part by the U.S. DOE, LLNL, and LLE.

  12. Total cross section measurement of radioactive isotopes with a thin beam neutron spectrometer

    International Nuclear Information System (INIS)

    Razbudej, V.F.; Vertebnyj, V.P.; Padun, G.S.; Muravitskij, A.V.

    1975-01-01

    The method for measuring the neutron total cross sections of radioactive isotopes by a time-of-flight spectrometer with a narrow (0.17 mm in diameter) beam of thermal neutrons is described. The distinguishing feature of this method is the use of capillary samples with a small amount of substance (0.05-1.0 mg). The energy range is 0.01-0.3 eV. The total cross sections of irradiated samples of sub(153)Eu and sub(151)Eu are measured. From them are obtained the cross sections of sub(152)Eu (Tsub(1/2)=12.4 g) and of sub(154)E (Tsub(1/2)=8.6 yr); they equal 11400+-1400 and 1530+-190 barn at E=0.0253 eV. The cross section of the sub(152)Eu absorption for the thermal spectrum (T=333 K) is determined by the activation method; it is 8900+-1200 barn

  13. The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF

    International Nuclear Information System (INIS)

    Casey, D. T.; Frenje, J. A.; Gatu Johnson, M.; Séguin, F. H.; Li, C. K.; Petrasso, R. D.; Glebov, V. Yu.; Katz, J.; Magoon, J.; Meyerhofer, D. D.; Sangster, T. C.; Shoup, M.; Ulreich, J.; Ashabranner, R. C.; Bionta, R. M.; Carpenter, A. C.; Felker, B.; Khater, H. Y.; LePape, S.; MacKinnon, A.

    2013-01-01

    The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, ion-temperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describes ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.

  14. The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF.

    Science.gov (United States)

    Casey, D T; Frenje, J A; Johnson, M Gatu; Séguin, F H; Li, C K; Petrasso, R D; Glebov, V Yu; Katz, J; Magoon, J; Meyerhofer, D D; Sangster, T C; Shoup, M; Ulreich, J; Ashabranner, R C; Bionta, R M; Carpenter, A C; Felker, B; Khater, H Y; LePape, S; MacKinnon, A; McKernan, M A; Moran, M; Rygg, J R; Yeoman, M F; Zacharias, R; Leeper, R J; Fletcher, K; Farrell, M; Jasion, D; Kilkenny, J; Paguio, R

    2013-04-01

    The neutron spectrum produced by deuterium-tritium (DT) inertial confinement fusion implosions contains a wealth of information about implosion performance including the DT yield, ion-temperature, and areal-density. The Magnetic Recoil Spectrometer (MRS) has been used at both the OMEGA laser facility and the National Ignition Facility (NIF) to measure the absolute neutron spectrum from 3 to 30 MeV at OMEGA and 3 to 36 MeV at the NIF. These measurements have been used to diagnose the performance of cryogenic target implosions to unprecedented accuracy. Interpretation of MRS data requires a detailed understanding of the MRS response and background. This paper describes ab initio characterization of the system involving Monte Carlo simulations of the MRS response in addition to the commission experiments for in situ calibration of the systems on OMEGA and the NIF.

  15. The monochromatic imaging mode of a RITA-type neutron spectrometer

    International Nuclear Information System (INIS)

    Bahl, C.R.H.; Andersen, P.; Klausen, S.N.; Lefmann, K.

    2004-01-01

    The imaging monochromatic mode of a neutron spectrometer with a multi-bladed RITA analyser system is so far unexplored. We present analytical calculations that define the mode. It is shown that the mode can be realised for PG (0 0 2) analyser crystals, from incident energies of about 3.2 meV and up, allowing the important cases of 3.7, 5.0 and 13.7 meV. Due to beam divergence, the neutron rays from neighbouring analyser blades are found to overlap slightly. Hence, the optimal use of the monochromatic imaging mode would be found by employing an adjustable radial collimator to limit the spread of the ray from each analyser blade

  16. The monochromatic imaging mode of a RITA-type neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, C.R.H. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark) and Department of Physics, Technical University of Denmark, DK-2800 Lyngby (Denmark)]. E-mail: christian.bahl@risoe.dk; Andersen, P. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Niels Bohr Institute for Astronomy, Physics and Geophysics, University of Copenhagen, DK-2100 Copenhagen (Denmark); Klausen, S.N. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Lefmann, K. [Department of Materials Research, Riso National Laboratory, Building 227, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

    2004-12-01

    The imaging monochromatic mode of a neutron spectrometer with a multi-bladed RITA analyser system is so far unexplored. We present analytical calculations that define the mode. It is shown that the mode can be realised for PG (0 0 2) analyser crystals, from incident energies of about 3.2 meV and up, allowing the important cases of 3.7, 5.0 and 13.7 meV. Due to beam divergence, the neutron rays from neighbouring analyser blades are found to overlap slightly. Hence, the optimal use of the monochromatic imaging mode would be found by employing an adjustable radial collimator to limit the spread of the ray from each analyser blade.

  17. The sensitivity of LaBr{sub 3}:Ce scintillation detectors to low energy neutrons: Measurement and Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tain, J.L., E-mail: tain@ific.uv.es [Instituto de Física Corpuscular, CSIC–Universidad de Valencia, Apdo. Correos 22085, E-46071 Valencia (Spain); Agramunt, J.; Algora, A. [Instituto de Física Corpuscular, CSIC–Universidad de Valencia, Apdo. Correos 22085, E-46071 Valencia (Spain); Aprahamian, A. [University of Notre Dame, Department of Physics, IN 46556, Notre Dame (United States); Cano-Ott, D. [Centro de Investigaciones Energéticas Medioambientales y Tecnológicas, E-28040 Madrid (Spain); Fraile, L.M. [Universidad Complutense, Grupo de Fisica Nuclear, CEI Moncloa, E-28040 Madrid (Spain); Guerrero, C. [CERN, Geneva (Switzerland); Jordan, M.D. [Instituto de Física Corpuscular, CSIC–Universidad de Valencia, Apdo. Correos 22085, E-46071 Valencia (Spain); Mach, H. [University of Notre Dame, Department of Physics, IN 46556, Notre Dame (United States); Universidad Complutense, Grupo de Fisica Nuclear, CEI Moncloa, E-28040 Madrid (Spain); Martinez, T.; Mendoza, E. [Centro de Investigaciones Energéticas Medioambientales y Tecnológicas, E-28040 Madrid (Spain); Mosconi, M.; Nolte, R. [Physikalisch-Technische Bundesanstalt, D-38116 Braunschweig (Germany)

    2015-02-21

    The neutron sensitivity of a cylindrical ⊘1.5 in.×1.5 in. LaBr{sub 3}:Ce scintillation detector was measured using quasi-monoenergetic neutron beams in the energy range from 40 keV to 2.5 MeV. In this energy range the detector is sensitive to γ-rays generated in neutron inelastic and capture processes. The experimental energy response was compared with Monte Carlo simulations performed with the Geant4 simulation toolkit using the so-called High Precision Neutron Models. These models rely on relevant information stored in evaluated nuclear data libraries. The performance of the Geant4 Neutron Data Library as well as several standard nuclear data libraries was investigated. In the latter case this was made possible by the use of a conversion tool that allowed the direct use of the data from other libraries in Geant4. Overall it was found that there was good agreement with experiment for some of the neutron data bases like ENDF/B-VII.0 or JENDL-3.3 but not with the others such as ENDF/B-VI.8 or JEFF-3.1.

  18. Multi-Grid detector for neutron spectroscopy: results obtained on time-of-flight spectrometer CNCS

    Science.gov (United States)

    Anastasopoulos, M.; Bebb, R.; Berry, K.; Birch, J.; Bryś, T.; Buffet, J.-C.; Clergeau, J.-F.; Deen, P. P.; Ehlers, G.; van Esch, P.; Everett, S. M.; Guerard, B.; Hall-Wilton, R.; Herwig, K.; Hultman, L.; Höglund, C.; Iruretagoiena, I.; Issa, F.; Jensen, J.; Khaplanov, A.; Kirstein, O.; Lopez Higuera, I.; Piscitelli, F.; Robinson, L.; Schmidt, S.; Stefanescu, I.

    2017-04-01

    The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.

  19. The performance of neutron scattering spectrometers at a long-pulse spallation source

    International Nuclear Information System (INIS)

    Pynn, R.

    1997-01-01

    In this document the author considers the performance of a long pulse spallation source for those neutron scattering experiments that are usually performed with a monochromatic beam at a continuous wave (CW) source such as a nuclear reactor. The first conclusion drawn is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons

  20. NEMUS--the PTB Neutron Multisphere Spectrometer Bonner spheres and more

    CERN Document Server

    Wiegel, B

    2002-01-01

    The original Bonner sphere spectrometer as it is used and characterized by PTB consists of 12 polyethylene spheres with diameters from 7.62 cm (3'') to 45.72 cm (18'') and a sup 3 He-filled spherical proportional counter used as a central thermal-neutron-sensitive detector and as a bare or cadmium-shielded bare detector. In this paper, a set of four new spheres made of polyethylene with copper or lead inlets is introduced. All spheres are less than 18 kg in mass and their responses to high energy neutrons increase with energy as a result of the increasing (n,xn) cross-sections of copper and lead. The fluence response matrix was calculated up to 10 GeV using an extended neutron cross-section library (LA150) and the MCNP(X) Monte Carlo code. Calibration measurements with neutron energies up to 60 MeV were used to compare the calculated response functions to measured values. For measurements outside the laboratory, a miniaturized, battery-powered electronic set-up was developed. This system with the additional, ...

  1. First Magnon of BATAN’s Neutron Triple-Axis Spectrometer

    Directory of Open Access Journals (Sweden)

    I. Sumirat

    2016-08-01

    Full Text Available The National Nuclear Energy Agency of Indonesia (BATAN has one dedicated spectrometer for inelastic neutron scattering experiments. The instrument is a thermal neutron triple-axis spectrometer known as SN1. SN1 was installed in 1992 in the experimental hall of G. A. Siwabessy Research Reactor, Serpong, Banten. Malfunctions of the hardware and software have prevented the instrument from performing inelastic scattering measurements since 1996. The 2011-2015 five years project has been initiated to revitalize and optimize the SN1. The project serves as a preparation for the utilization of SN1 for the investigation of lattice dynamics, spin wave and magnetic excitations in condensed matters that will be started in 2016. In 2013, SN1 has successfully been repaired and was able to measure phonon dispersion relation of available single crystals, i.e., Cu, pyrolytic graphite (PG, Ge, and Al. In 2015, the first experiment on magnetic excitation to investigate magnon dispersion relation of a known Fe single crystal has been carried out. Standard methods of inelastic scattering measurements, i.e., a constant-energy transfer hω with either fixed final neutron energy Ef = 14.7 meV or fixed incoming neutron energy Ei = 30.59 meV, and a constant momentum transfer Q with fixed incoming neutron energy Ei = 30.59 meV, were applied to measure the low-energy magnetic excitations. For fixed Ef measurement, a 5-cm thick PG filter was set between the sample and the analyzer to eliminate λ/n harmonics. To limit the energy and momentum spreads of the beam, collimations of 40 minutes were applied before and after the sample. The spin waves were measured along the three principal symmetry directions of [00ζ], [ζζ0], and [ζζζ]. The measured magnons were compared to values in reference and were found to be in a good agreement with them. With such accomplishments, we are convinced that SN1 is now ready for its inelastic scattering application and will become one of

  2. Neutron reference spectra measurements with the Bonner multi-spheres spectrometer

    International Nuclear Information System (INIS)

    Lemos Junior, Roberto Mendonca de

    2004-01-01

    This paper aims to define a procedure to use the Bonner Multisphere Spectrometer with a 6 LiI(Eu) detector in order to determine of neutron spectra. It was measured 238 PuBe spectra and same of reference ( 241 AmBe, 252 Cf e 252 Cf+D 2 O) published in ISO 8529-1 (2001) Norm. The data were processed by a computer program (BUNKI), which presents the results in neutrons energy fluency. Each input parameter of the program was studied in order to establish their influence in the adjustment result. The environment dose equivalent rate obtained placing the detector 1 m from the 241 AmBe source was 122 ± 4 μSv/h with 7% of uncertainty and 95% of confidence level. The procedure established in this work was tested with the 238 PuBe spectrum, obtaining an environment dose equivalent rate of 286 ± 9 μSv/h, 8% lower than the value measured experimentally used as reference. Through this procedure will be possible to measure neutron spectra in different work places where neutrons sources are used. Knowing these spectra, it will be possible to evaluate which area monitors, are more suitable, as well as, to study better the response of individual neutron monitors, as for instance, to obtain a conversion coefficient more appropriate to the albedo dosimeter used in different work places. As the measurements need a long time to be accomplished, the work optimization is fundamental to reduce the exposing time of the Bonner spectrometer operator. For this reason, an important parameter examined in this paper was the possibility of reducing the number of spheres used during the measurement without changing the final result. Considering the radiation protection standards, this parameter has a huge importance when the measurements are performed in work places where the neutron fluency and gamma rate offer risks to the operator's health, as for instance, in nuclear centrals. Studying this parameter, it was possible to conclude that removing the 20,32 cm diameter sphere it will be

  3. First magnon of BATAN's neutron triple-axis spectrometer

    International Nuclear Information System (INIS)

    I Sumirat

    2016-01-01

    The National Nuclear Energy Agency of Indonesia (BATAN) has one dedicated spectrometer for inelastic neutron scattering experiments. The instrument is a thermal neutron triple-axis spectrometer known as SN1. SN1 was installed in 1992 in the experimental hall of G. A. Siwabessy Research Reactor, Serpong, Banten. Malfunctions of the hardware and software have prevented the instrument from performing inelastic scattering measurements since 1996. The 2011-2015 five years project has been initiated to revitalize and optimize the SN1. The project serves as a preparation for the utilization of SN1 for the investigation of lattice dynamics, spin wave and magnetic excitations in condensed matters that will be started in 2016. In 2013, SN1 has successfully been repaired and was able to measure phonon dispersion relation of available single crystals, i.e., Cu, pyrolytic graphite (PG), Ge, and Al. In 2015, the first experiment on magnetic excitation to investigate magnon dispersion relation of a known Fe single crystal has been carried out. Standard methods of inelastic scattering measurements, i.e., a constant-energy transfer hω with either fixed final neutron energy E f = 14.7 MeV or fixed incoming neutron energy E i = 30.59 MeV, and a constant momentum transfer Q with fixed incoming neutron energy E i = 30.59 MeV, were applied to measure the low-energy magnetic excitations. For fixed E f measurement, a 5-cm thick PG filter was set between the sample and the analyzer to eliminate λ/n harmonics. To limit the energy and momentum spreads of the beam, collimations of 40 minutes were applied before and after the sample. The spin waves were measured along the three principal symmetry directions of [00ζ], [ζζ0], and [ζζζ] . The measured magnons were compared to values in reference and were found to be in a good agreement with them. With such accomplishments, we are convinced that SN1 is now ready for its inelastic scattering application and will become one of BATAN

  4. Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF{sub 6} neutron scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Kenichi, E-mail: k-watanabe@nucl.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Yamazaki, Takuya; Sugimoto, Dai; Yamazaki, Atsushi; Uritani, Akira; Iguchi, Tetsuo [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Fukuda, Kentaro; Ishidu, Sumito [Tokuyama Corporation, Shunan 745-8648 (Japan); Yanagida, Takayuki; Fujimoto, Yutaka [Kyushu Institute of Technology, Kita-kyushu 808-0196 (Japan)

    2015-06-01

    As an alternative to the standard {sup 3}He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST) Eu doped LiCaAlF{sub 6} (Eu:LiCAF) scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to readout scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUST Eu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm{sup 3} was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron absolute detection efficiency is evaluated to be 8.8×10{sup −7} and 9×10{sup −3} cps/ng Cf (2 m) for the TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm{sup 3}.

  5. Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF6 neutron scintillator

    International Nuclear Information System (INIS)

    Watanabe, Kenichi; Yamazaki, Takuya; Sugimoto, Dai; Yamazaki, Atsushi; Uritani, Akira; Iguchi, Tetsuo; Fukuda, Kentaro; Ishidu, Sumito; Yanagida, Takayuki; Fujimoto, Yutaka

    2015-01-01

    As an alternative to the standard 3 He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST) Eu doped LiCaAlF 6 (Eu:LiCAF) scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to readout scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUST Eu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm 3 was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron absolute detection efficiency is evaluated to be 8.8×10 −7 and 9×10 −3 cps/ng Cf (2 m) for the TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm 3

  6. A prototype fully digital data acquisition system upgrade for the TOFOR neutron spectrometer at JET

    Energy Technology Data Exchange (ETDEWEB)

    Skiba, Mateusz, E-mail: mateusz.skiba@physics.uu.se [Department of Physics and Astronomy, Uppsala University (Sweden); Ericsson, Göran; Hjalmarsson, Anders; Hellesen, Carl; Conroy, Sean; Andersson-Sundén, Erik; Eriksson, Jacob [Department of Physics and Astronomy, Uppsala University (Sweden); JET Contributors [EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

    2016-10-11

    A prototype of a fully digital data acquisition system upgrade for the TOFOR time-of-flight fusion neutron spectrometer at JET has been implemented and evaluated. The core of the system is composed of five fast PXIe waveform digitisers (1 GSPS, 12 bits) with large internal fast memory (1 GB). Due to the complexity and high requirements on timing precision of the spectrometer, the design and implementation of such a system poses numerous technical challenges, in particular regarding time alignment and synchronisation of signal paths and digitiser modules. These issues and their solutions, as pertaining to the TOFOR spectrometer, are presented in detail in the present paper. As a final assessment of the ability of the new data acquisition system to reproduce the capabilities of the original TOFOR system, a thorough comparison of results produced using both systems is presented. The comparison with TOFOR has been performed with satisfying results. Two immediate advantages of the new data acquisition system are significantly improved triggering dead time (from about 70 ns to 10 ns) and the ability to adjust the triggering thresholds as needed during the analysis step. The enhanced spectroscopic capabilities of the new data acquisition system will be reported on in future publications.

  7. High-pressure {sup 3}He-Xe gas scintillators for simultaneous detection of neutrons and gamma rays over a large energy range

    Energy Technology Data Exchange (ETDEWEB)

    Tornow, W., E-mail: tornow@tunl.duke.edu [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Esterline, J.H. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Leckey, C.A. [Department of Physics, The College of William and Mary, Williamsburg, VA 23187 (United States); Weisel, G.J. [Department of Physics, Penn State Altoona, Altoona, PA 16601 (United States)

    2011-08-11

    We report on features of high-pressure {sup 3}He-Xe gas scintillators which have not been sufficiently addressed in the past. Such gas scintillators can be used not only for the efficient detection of low-energy neutrons but at the same time for the detection and identification of {gamma}-rays as well. Furthermore, {sup 3}He-Xe gas scintillators are also very convenient detectors for fast neutrons in the 1-10 MeV energy range and for high-energy {gamma}-rays in the 7-15 MeV energy range. Due to their linear pulse-height response and self calibration via the {sup 3}He(n,p){sup 3}H reaction, neutron and {gamma}-ray energies can easily be determined in this high-energy regime.

  8. High-pressure 3He-Xe gas scintillators for simultaneous detection of neutrons and gamma rays over a large energy range

    International Nuclear Information System (INIS)

    Tornow, W.; Esterline, J.H.; Leckey, C.A.; Weisel, G.J.

    2011-01-01

    We report on features of high-pressure 3 He-Xe gas scintillators which have not been sufficiently addressed in the past. Such gas scintillators can be used not only for the efficient detection of low-energy neutrons but at the same time for the detection and identification of γ-rays as well. Furthermore, 3 He-Xe gas scintillators are also very convenient detectors for fast neutrons in the 1-10 MeV energy range and for high-energy γ-rays in the 7-15 MeV energy range. Due to their linear pulse-height response and self calibration via the 3 He(n,p) 3 H reaction, neutron and γ-ray energies can easily be determined in this high-energy regime.

  9. Some features and results of thermal neutron background measurements with the [ZnS(Ag)+{sup 6}LiF] scintillation detector

    Energy Technology Data Exchange (ETDEWEB)

    Kuzminov, V.V.; Alekseenko, V.V.; Barabanov, I.R.; Etezov, R.A.; Gangapshev, A.M.; Gavrilyuk, Yu.M.; Gezhaev, A.M.; Kazalov, V.V. [Institute for Nuclear Research, 117312 Moscow (Russian Federation); Khokonov, A.Kh. [Kh.M. Berbekov Kabardino-Balkarian State University, 360004 (Russian Federation); Panasenko, S.I. [V.N. Karazin Kharkiv National University, 61022 Kharkiv (Ukraine); Ratkevich, S.S., E-mail: ssratk@gmail.com [V.N. Karazin Kharkiv National University, 61022 Kharkiv (Ukraine)

    2017-01-01

    Features of a thermal neutron test detector with thin scintillator [ZnS(Ag)+{sup 6}LiF] are described. Background of the detector and its registration efficiency were defined as a result of measurements. The thermal neutron flux at different locations, and for different conditions around the Baksan Neutrino Observatory are reported. - Highlights: • This paper describes tests of a thermal neutron detector based on a thin scintillator ZnS(Ag) with {sup 6}LiF. • The results are a measurement of the background neutron flux from the detector and the detector's efficiency. • The thermal neutron flux at different locations, and for different conditions around the Baksan Neutrino Observatory are reported.

  10. Neutron/gamma discrimination employing the power spectrum analysis of the signal from the liquid scintillator BC501A

    International Nuclear Information System (INIS)

    Luo, X.L.; Wang, Y.K; Yang, J.; Liu, G.; Lin, C.B.; Hu, Q.Q.; Peng, J.X.

    2013-01-01

    A digital method for the discrimination of neutron and γ-ray events based on analyzing the power spectra of the signals from a BC501A liquid scintillator detector was presented and investigated in this paper. In order to evaluate the feasibility of this novel pulse shape discrimination method, a 5GSample/s 8-bit oscilloscope was used to acquire waveforms for n/γ discrimination. Furthermore, the performance of this novel n/γ discrimination method was compared with that of a widely used method called the reference-pulses method which averaged a large number of neutron and γ-ray pulses to obtain the reference-pulse as the criterion for n/γ discrimination. The results showed that the proposed method performed well over the reference-pulses method, which was verified by the considerable decrease in the error rate of n/γ discrimination and the improvement of the Figure of Merit

  11. Distinguishing new science from calibration effects in the electron-volt neutron spectrometer VESUVIO at ISIS

    International Nuclear Information System (INIS)

    Chatzidimitriou-Dreismann, C.A.; Gray, E. MacA.; Blach, T.P.

    2012-01-01

    The “standard” procedure for calibrating the Vesuvio eV neutron spectrometer at the ISIS neutron source, forming the basis for data analysis over at least the last decade, was recently documented in considerable detail by the instrument's scientists. Additionally, we recently derived analytic expressions of the sensitivity of recoil peak positions with respect to fight-path parameters and presented neutron–proton scattering results that together called into question the validity of the “standard” calibration. These investigations should contribute significantly to the assessment of the experimental results obtained with Vesuvio. Here we present new results of neutron–deuteron scattering from D 2 in the backscattering angular range (θ>90°) which are accompanied by a striking energy increase that violates the Impulse Approximation, thus leading unequivocally the following dilemma: (A) either the “standard” calibration is correct and then the experimental results represent a novel quantum dynamical effect of D which stands in blatant contradiction of conventional theoretical expectations; (B) or the present “standard” calibration procedure is seriously deficient and leads to artificial outcomes. For Case (A), we allude to the topic of attosecond quantum dynamical phenomena and our recent neutron scattering experiments from H 2 molecules. For Case (B), some suggestions as to how the “standard” calibration could be considerably improved are made.

  12. Experimental verification of a new neutron spectrometer for environmental dosimetry and area; Verficiacion experimental de un nuevo espectrometro de neutrones para dosimetria ambiental y de area

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Ros, J. M.; Romero, A.; Begogini, R.; Esposito, A.; Moraleda, M.; Lagares, J. I.; Sansaloni, F.; Arce, P.; Llop, J.

    2011-07-01

    In this communication, we present experimental results with a new neutron spectrometer, developed jointly by the Radiation Dosimetry Unit of CIEMAT Unita di Fisica and INFN-LNF Sanitary (Italy), consisting of a polyethylene moderating sphere detectors thermal neutrons (paired thermoluminescent dosimeters and activation foils) located in different positions. The device configuration and distribution of dosimeters are designed to elicit a response in a nearly isotropic up to 20 MeV energy range. (Author)

  13. Measuring the absolute deuterium-tritium neutron yield using the magnetic recoil spectrometer at OMEGA and the NIF.

    Science.gov (United States)

    Casey, D T; Frenje, J A; Gatu Johnson, M; Séguin, F H; Li, C K; Petrasso, R D; Glebov, V Yu; Katz, J; Knauer, J P; Meyerhofer, D D; Sangster, T C; Bionta, R M; Bleuel, D L; Döppner, T; Glenzer, S; Hartouni, E; Hatchett, S P; Le Pape, S; Ma, T; MacKinnon, A; McKernan, M A; Moran, M; Moses, E; Park, H-S; Ralph, J; Remington, B A; Smalyuk, V; Yeamans, C B; Kline, J; Kyrala, G; Chandler, G A; Leeper, R J; Ruiz, C L; Cooper, G W; Nelson, A J; Fletcher, K; Kilkenny, J; Farrell, M; Jasion, D; Paguio, R

    2012-10-01

    A magnetic recoil spectrometer (MRS) has been installed and extensively used on OMEGA and the National Ignition Facility (NIF) for measurements of the absolute neutron spectrum from inertial confinement fusion implosions. From the neutron spectrum measured with the MRS, many critical implosion parameters are determined including the primary DT neutron yield, the ion temperature, and the down-scattered neutron yield. As the MRS detection efficiency is determined from first principles, the absolute DT neutron yield is obtained without cross-calibration to other techniques. The MRS primary DT neutron measurements at OMEGA and the NIF are shown to be in excellent agreement with previously established yield diagnostics on OMEGA, and with the newly commissioned nuclear activation diagnostics on the NIF.

  14. Desktop calculator-assisted liquid scintillation spectrometry of 3H and 14C with special consideration of low level activities and spectrometer instability

    International Nuclear Information System (INIS)

    Jordan, P.; May, K.

    1977-01-01

    For the liquid scintillation measurement of 3 H and 14 C in single- and dual-labelled samples with the same spectrometer settings, which are desirable for routine work, the lower discriminator level of the 14 C channel has to be set down to a value for which the tritium crosstalk α amounts to about 15%. Under these conditions, the short time variations of α are important for the overall attainable precision. A simple method for the automatic computation of drift corrections based on the continuous measurement of a standard sample is presented. Furthermore, for low activities an appreciable improvement of the precision may be achieved by systemetic re-use of the glass vials together with the cumulated measurements of their individual backgrounds. The precision of low activity measurements is also enhanced by correction of background counting rates for quenching

  15. Observations of celestial X-ray sources above 20 keV with the high-energy scintillation spectrometer on board OSO-8

    International Nuclear Information System (INIS)

    Crannell, C.J.; Dennis, B.R.; Dolan, J.F.; Frost, K.J.; Orwig, L.E.; Maurer, G.S.

    1977-01-01

    High-energy x-ray spectra of the Crab Nebula, Cyg XR-1, and Cen A have been determined from observations with the scintillation spectrometer on board the OSO-8 satellite, launched in June, 1975. Each of these sources was observed over two periods of 8 days or more, enabling a search for day-to-day and year-to-year variations in the spectral and temporal characteristics of the x-ray emission. No variation in the light curve of the Crab pulsar has been found from observations which span a 15-day period in March 1976, with demonstrable phase stability. Transitions associated with the binary phase of Cyg XR-1 and a large change in the emission from Cen A are reported

  16. A novel fast-neutron tomography system based on a plastic scintillator array and a compact D-D neutron generator.

    Science.gov (United States)

    Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

    2016-01-01

    Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion

  17. Independent measuring station for the GNEJS neutron spectrometer information and measurement system

    International Nuclear Information System (INIS)

    Gorokhov, I.S.; Laptev, A.B.; Marchenkov, V.V.; Tubol'tsev, Yu.V.; Fokin, E.Yu.; Shcherbakov, O.A.

    1984-01-01

    An independent measuring station (IMS) being a part of the information and measuring system of the neutron time-of-flight spectrometer is described. IMS represents the time (time-to-amplitude or time-to-angular) module analyzer assembled on the base of one or several CAMAC crates. The station permits to perform time measurements as well as the time measurements with amplitude weighing in an independent mode with subseqUent data transmission the central PDP-11/05 computer. The station processor unit is an independent controller. The software consists of the programming langUage of the controller from local terminal and programs ensuring measuring and shaping the spectra with their output on TV display devic. communication with the computer and dialogue with the operator

  18. Neutron-damaged GaAs detectors for use in a Compton spectrometer

    International Nuclear Information System (INIS)

    Kammeraad, J.E.; Sale, K.E.; Wang, C.L.; Baltrusaitis, R.M.

    1992-01-01

    Detectors made of GaAs are being studies for use on the focal plane of a Compton spectrometer which measures 1-MeV to 25-MeV gamma rays with high energy resolution (1% or 100 keV, whichever is greater) and 200-ps time resolution. The detectors are GaAs chips that have been neutron-damaged to improve the time response. The detectors will be used to measure fast transient signals in the current mode. The properties of various GaAs detector configurations are being studied by bombarding sample detectors with short pulses of 4-MeV to 16-MeV electrons at the Linac Facility at EG ampersand G Energy Measurements, Inc., Santa Barbara Operations. Measurements of detector sensitivity and impulse response versus detector bias, thickness, and electron beam energy and intensity have been performed and are presented. 5 refs

  19. Choppers to optimise the repetition rate multiplication technique on a direct geometry neutron chopper spectrometer

    International Nuclear Information System (INIS)

    Vickery, A.; Deen, P. P.

    2014-01-01

    In recent years the use of repetition rate multiplication (RRM) on direct geometry neutron spectrometers has been established and is the common mode of operation on a growing number of instruments. However, the chopper configurations are not ideally optimised for RRM with a resultant 100 fold flux difference across a broad wavelength band. This paper presents chopper configurations that will produce a relative constant (RC) energy resolution and a relative variable (RV) energy resolution for optimised use of RRM. The RC configuration provides an almost uniform ΔE/E for all incident wavelengths and enables an efficient use of time as the entire dynamic range is probed with equivalent statistics, ideal for single shot measurements of transient phenomena. The RV energy configuration provides an almost uniform opening time at the sample for all incident wavelengths with three orders of magnitude in time resolution probed for a single European Spallation Source (ESS) period, which is ideal to probe complex relaxational behaviour. These two chopper configurations have been simulated for the Versatile Optimal Resolution direct geometry spectrometer, VOR, that will be built at ESS

  20. High-sensitive spectrometer of fast neutrons and the results of fast neutron background flux measurements at the gallium-germanium solar neutrino experiment (SAGE)

    International Nuclear Information System (INIS)

    Abdurashitov, D.N.; Gavrin, V.N.; Kalikhov, A.V.; Matushko, V.L.; Shikhin, A.A.; Yants, V.E.; Zaborskaya, O.S.

    2001-01-01

    The principle of operation, design, registration system and main characteristics of a fast neutron spectrometer are described. The spectrometer is intended for direct measurements of ultra-low fluxes of fast neutrons. It is sensitive to neutron fluxes of 10 -7 cm -2 · s -1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11 ± 0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5 ± 2.1) · 10 -7 cm -2 · s -1 in the range of 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4600 meters of water equivalent was measured to be (7.3 ± 2.4) · 10 -7 cm -2 · s -1 in the interval 1.0 -11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be 2.3 · 10 -7 cm -2 · s -1 in 1.0 - 11.0 MeV energy range

  1. High-sensitive spectrometer of fast neutrons and the results of fast neutron background flux measurements at the Gallium-Germanium Solar Neutrino Experiment

    CERN Document Server

    Abdurashitov, J N; Kalikhov, A V; Matushko, V L; Shikhin, A A; Yants, V E; Zaborskaia, O S

    2002-01-01

    The principle of operation, design, registration system and main characteristics of a fast neutron spectrometer are described. The spectrometer is intended for direct measurements of ultra low fluxes of fast neutrons. It is sensitive to neutron fluxes of 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11+-0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5+-2.1)x10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4600 m of water equivalent was measured to be (7.3+-2.4)x10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be <2.3x10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in 1.0-11.0 MeV energy range.

  2. Characterization of the neutron field at the ISIS-VESUVIO facility by means of a bonner sphere spectrometer

    International Nuclear Information System (INIS)

    Bedogni, Roberto; Esposito, Adolfo; Andreani, Carla; Senesi, Roberto; De Pascale, Maria Pia; Picozza, Piergiorgio; Pietropaolo, Antonino; Gorini, Giuseppe; Frost, Christopher D.; Ansell, Stewart

    2009-01-01

    One of the more actual and promising fields of applied neutron physics is the investigation of the malfunctions induced by high-energy neutrons naturally present in the atmosphere in electronic devices, called single event effects (SEE). These studies are of primary importance for the design of devices that have to fulfill high reliability requirements and those that are likely to be exposed to enhanced levels of cosmic rays background, e.g. in aerospace and avionic applications. Particle accelerators-driven neutron sources constitute valuable irradiation facilities for these purposes as they provide an opportunity for accelerated testing of the effects of these naturally occurring neutrons, provided the neutron spectrum is comparable with the atmospheric one and the neutron fields are known with high accuracy. The latter can be achieved through the use of appropriate radiation transport codes and neutron spectrometry techniques. In view of the design and construction of CHIPIR, a dedicated beam line for SEE studies at the ISIS pulsed neutron source second target station (UK) ((http://ts-2.isis.rl.ac.uk/instruments/phase2/index.htm)), a spectrometric characterization was performed on the VESUVIO beamline (Senesi et al.,2000). The spectrometric technique was the bonner sphere spectrometer (BSS), widely used to determine neutron spectra and dose quantities around high-energy accelerators. The experimental campaign provided a complete spectrometric investigation of the VESUVIO neutron beam, allowing the integral quantities (total fluence rate, fraction of fluence in given energy intervals) to be estimated with uncertainties lower than 10%.

  3. Characterization of the neutron field at the ISIS-VESUVIO facility by means of a bonner sphere spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, Roberto; Esposito, Adolfo [INFN-LNF Via E. Fermi n. 40-00044 Frascati (RM) (Italy); Andreani, Carla [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica e Centro NAST, Via R. Scientifica 1, 00133 Roma (Italy); Senesi, Roberto, E-mail: roberto.senesi@roma2.infn.i [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica e Centro NAST, Via R. Scientifica 1, 00133 Roma (Italy); De Pascale, Maria Pia; Picozza, Piergiorgio [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica e Centro NAST, Via R. Scientifica 1, 00133 Roma (Italy); Pietropaolo, Antonino; Gorini, Giuseppe [CNISM and Universita degli Studi di Milano Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Frost, Christopher D. [INFN-LNF Via E. Fermi n. 40-00044 Frascati (RM) (Italy); Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica e Centro NAST, Via R. Scientifica 1, 00133 Roma (Italy); CNISM and Universita degli Studi di Milano Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); STFC Rutherford Appleton Laboratory, ISIS Facility, Harwell Science and Innovation Campus, Didcot, Oxon, OX11 0QX (United Kingdom); Ansell, Stewart [STFC Rutherford Appleton Laboratory, ISIS Facility, Harwell Science and Innovation Campus, Didcot, Oxon, OX11 0QX (United Kingdom)

    2009-12-21

    One of the more actual and promising fields of applied neutron physics is the investigation of the malfunctions induced by high-energy neutrons naturally present in the atmosphere in electronic devices, called single event effects (SEE). These studies are of primary importance for the design of devices that have to fulfill high reliability requirements and those that are likely to be exposed to enhanced levels of cosmic rays background, e.g. in aerospace and avionic applications. Particle accelerators-driven neutron sources constitute valuable irradiation facilities for these purposes as they provide an opportunity for accelerated testing of the effects of these naturally occurring neutrons, provided the neutron spectrum is comparable with the atmospheric one and the neutron fields are known with high accuracy. The latter can be achieved through the use of appropriate radiation transport codes and neutron spectrometry techniques. In view of the design and construction of CHIPIR, a dedicated beam line for SEE studies at the ISIS pulsed neutron source second target station (UK) ((http://ts-2.isis.rl.ac.uk/instruments/phase2/index.htm)), a spectrometric characterization was performed on the VESUVIO beamline (Senesi et al.,2000). The spectrometric technique was the bonner sphere spectrometer (BSS), widely used to determine neutron spectra and dose quantities around high-energy accelerators. The experimental campaign provided a complete spectrometric investigation of the VESUVIO neutron beam, allowing the integral quantities (total fluence rate, fraction of fluence in given energy intervals) to be estimated with uncertainties lower than 10%.

  4. The use of fast and thermal neutron detectors based on oxide scintillators in inspection systems for prevention of illegal transportation of radioactive substances

    International Nuclear Information System (INIS)

    Ryzhikov, V. D.; Grinyov, B. V.; Piven, L. A.; Pochet, T.; Onyshchenko, G. M.; Lysetska, O. K.; Nagornaya, L. L.

    2009-01-01

    We present results of our studies aimed at practical application of an efficient method for detection of fast and thermal neutrons, which uses the process of inelastic scattering on atom nuclei present in inorganic scintillators. Due to energy transformation in inelastic scattering, the main fraction of gamma-radiation energy falls into the low-energy range (below 0.3 MeV). Detection in this range ensures efficiency that reaches up to 70% (as compared with 1% using conventional LiI(E)-techniques) and depends on the effective atomic number of the scintillator. The most evident practical application field for this method is inspection systems for prevention of illegal transportation of radioactive substances. Especially promising is the creation of a small-sized neutron detector for portable radioactive materials detection systems using the 'scintillator-avalanche photodiode' technology

  5. 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...... 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....

  6. Single crystal spectrometer FOX at KENS

    International Nuclear Information System (INIS)

    Takahashi, M.

    2001-01-01

    Single crystal spectrometer FOX installed at H1 thermal neutron line on KENS has been renewed recently for the measurement of very weak scattering. We have installed a multidetector system of 36 linearly placed 3 He detectors with collimators instead of former four-circle diffractometer and scintillator detectors. Though the system is quite simple, a large two-dimensional reciprocal space is observed effectively with high S/N rate on new FOX. (author)

  7. Simulation for developing new pulse neutron spectrometers I. Creation of new McStas components of moderators of JSNS

    CERN Document Server

    Tamura, I; Arai, M; Harada, M; Maekawa, F; Shibata, K; Soyama, K

    2003-01-01

    Moderators components of the McStas code have been created for the design of JSNS instruments. Three cryogenic moderators are adopted in JSNS, one is coupled H sub 2 moderators for high intensity experiments and other two are decoupled H sub 2 with poisoned or unpoisoned for high resolution moderators. Since the characteristics of neutron beams generated from moderators make influence on the performance of pulse neutron spectrometers, it is important to perform the Monte Carlo simulation with neutron source component written precisely. The neutron spectrum and time structure were calculated using NMTC/JAERI97 and MCNP4a codes. The simulation parameters, which describe the pulse shape over entire spectrum as a function of time, are optimized. In this paper, the creation of neutron source components for port No.16 viewed to coupled H sub 2 moderator and for port No.11 viewed to decoupled H sub 2 moderator of JSNS are reported.

  8. The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF)

    Energy Technology Data Exchange (ETDEWEB)

    Frenje, J. A., E-mail: jfrenje@psfc.mit.edu; Wink, C. W.; Gatu Johnson, M.; Li, C. K.; Séguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hilsabeck, T. J.; Kilkenny, J. D. [General Atomics, San Diego, California 92186 (United States); Bell, P.; Bionta, R.; Cerjan, C. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (T{sub i}), yield (Y{sub n}), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10{sup 16}. At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.

  9. The magnetic recoil spectrometer (MRSt) for time-resolved measurements of the neutron spectrum at the National Ignition Facility (NIF).

    Science.gov (United States)

    Frenje, J A; Hilsabeck, T J; Wink, C W; Bell, P; Bionta, R; Cerjan, C; Gatu Johnson, M; Kilkenny, J D; Li, C K; Séguin, F H; Petrasso, R D

    2016-11-01

    The next-generation magnetic recoil spectrometer for time-resolved measurements of the neutron spectrum has been conceptually designed for the National Ignition Facility. This spectrometer, called MRSt, represents a paradigm shift in our thinking about neutron spectrometry for inertial confinement fusion applications, as it will provide simultaneously information about the burn history and time evolution of areal density (ρR), apparent ion temperature (T i ), yield (Y n ), and macroscopic flows during burn. From this type of data, an assessment of the evolution of the fuel assembly, hotspot, and alpha heating can be made. According to simulations, the MRSt will provide accurate data with a time resolution of ∼20 ps and energy resolution of ∼100 keV for total neutron yields above ∼10 16 . At lower yields, the diagnostic will be operated at a higher-efficiency, lower-energy-resolution mode to provide a time resolution of ∼20 ps.

  10. Spin exchange optical pumping based polarized 3He filling station for the Hybrid Spectrometer at the Spallation Neutron Source.

    Science.gov (United States)

    Jiang, C Y; Tong, X; Brown, D R; Culbertson, H; Graves-Brook, M K; Hagen, M E; Kadron, B; Lee, W T; Robertson, J L; Winn, B

    2013-06-01

    The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60° horizontal and 15° vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized (3)He filling station based on the spin exchange optical pumping method. It is designed to supply polarized (3)He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the (3)He pressure with respect to the scattered neutron energies. The depolarized (3)He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

  11. BUMS--Bonner sphere Unfolding Made Simple: an HTML based multisphere neutron spectrometer unfolding package

    International Nuclear Information System (INIS)

    Sweezy, Jeremy; Hertel, Nolan; Veinot, Ken

    2002-01-01

    A new multisphere neutron spectrometer unfolding package, Bonner sphere Unfolding Made Simple (BUMS) has been developed that uses an HTML interface to simplify data input and code execution for the novice and the advanced user. This new unfolding package combines the unfolding algorithms contained in other popular unfolding codes under one easy to use interface. The interface makes use of web browsing software to provide a graphical user interface to the unfolding algorithms. BUMS integrates the SPUNIT, BON, MAXIET, and SAND-II unfolding algorithms into a single package. This package also includes a library of 14 response matrices, 58 starting spectra, and 24 dose and detector responses. BUMS has several improvements beyond the addition of unfolding algorithms. It has the ability to search for the most appropriate starting spectra. Also, plots of the unfolded neutron spectra are automatically generated. The BUMS package runs via a web server and may be accessed by any computer with access to the Internet at http://nukeisit.gatech.edu/bums

  12. Constant-q data representation in Neutron Compton scattering on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Senesi, R.; Pietropaolo, A.; Andreani, C.

    2008-01-01

    Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,ω). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved

  13. Constant-q data representation in Neutron Compton scattering on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Senesi, R. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy); Centro NAST, Nanoscienze and Nanotecnologie and Strumentazione, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: roberto.senesi@roma2.infn.it; Pietropaolo, A.; Andreani, C. [Dipartimento di Fisica, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy); Centro NAST, Nanoscienze and Nanotecnologie and Strumentazione, Universita degli Studi di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Roma (Italy)

    2008-09-01

    Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,{omega}). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved.

  14. Constant- q data representation in Neutron Compton scattering on the VESUVIO spectrometer

    Science.gov (United States)

    Senesi, R.; Pietropaolo, A.; Andreani, C.

    2008-09-01

    Standard data analysis on the VESUVIO spectrometer at ISIS is carried out within the Impulse Approximation framework, making use of the West scaling variable y. The experiments are performed using the time-of-flight technique with the detectors positioned at constant scattering angles. Line shape analysis is routinely performed in the y-scaling framework, using two different (and equivalent) approaches: (1) fitting the parameters of the recoil peaks directly to fixed-angle time-of-flight spectra; (2) transforming the time-of-flight spectra into fixed-angle y spectra, referred to as the Neutron Compton Profiles, and then fitting the line shape parameters. The present work shows that scattering signals from different fixed-angle detectors can be collected and rebinned to obtain Neutron Compton Profiles at constant wave vector transfer, q, allowing for a suitable interpretation of data in terms of the dynamical structure factor, S(q,ω). The current limits of applicability of such a procedure are discussed in terms of the available q-range and relative uncertainties for the VESUVIO experimental set up and of the main approximations involved.

  15. A new three-tier architecture design for multi-sphere neutron spectrometer with the FLUKA code

    Science.gov (United States)

    Huang, Hong; Yang, Jian-Bo; Tuo, Xian-Guo; Liu, Zhi; Wang, Qi-Biao; Wang, Xu

    2016-07-01

    The current commercially, available Bonner sphere neutron spectrometer (BSS) has high sensitivity to neutrons below 20 MeV, which causes it to be poorly placed to measure neutrons ranging from a few MeV to 100 MeV. The paper added moderator layers and the auxiliary material layer upon 3He proportional counters with FLUKA code, with a view to improve. The results showed that the responsive peaks to neutrons below 20 MeV gradually shift to higher energy region and decrease slightly with the increasing moderator thickness. On the contrary, the response for neutrons above 20 MeV was always very low until we embed auxiliary materials such as copper (Cu), lead (Pb), tungsten (W) into moderator layers. This paper chose the most suitable auxiliary material Pb to design a three-tier architecture multi-sphere neutron spectrometer (NBSS). Through calculating and comparing, the NBSS was advantageous in terms of response for 5-100 MeV and the highest response was 35.2 times the response of polyethylene (PE) ball with the same PE thickness.

  16. Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Abernathy, D. L.; Stone, M. B.; Loguillo, M. J.; Lucas, M. S.; Delaire, O.; Tang, X.; Lin, J. Y. Y.; Fultz, B.

    2012-01-01

    The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of 3 He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.

  17. Neutron and gamma-ray spectra of 239PuBe and 241AmBe

    International Nuclear Information System (INIS)

    Vega-Carrillo, H.R.; Manzanares-Acuna, Eduardo; Becerra-Ferreiro, A.M.; Carrillo-Nunez, Aureliano

    2002-01-01

    Neutron and gamma-ray spectra of 239 PuBe and 241 AmBe were measured and their dosimetric features were calculated. Neutron spectra were measured using a multisphere neutron spectrometer with a 6 LiI(Eu) scintillator. The 239 PuBe neutron spectrum was measured in an open environment, while the 241 AmBe neutron spectrum was measured in a closed environment. Gamma-ray spectra were measured using a NaI(Tl) scintillator using the same experimental conditions for both sources. The effect of measuring conditions for the 241 AmBe neutron spectrum indicates the presence of epithermal and thermal neutrons. The low-resolution neutron spectra obtained with the multisphere spectrometer allows one to calculate the dosimetric features of neutron sources. At 100 cm both sources produce approximately the same count rate as that of the 4.4 MeV gamma-ray per unit of alpha emitter activity

  18. Systems and methods for neutron detection using scintillator nano-materials

    Science.gov (United States)

    Letant, Sonia Edith; Wang, Tzu-Fang

    2016-03-08

    In one embodiment, a neutron detector includes a three dimensional matrix, having nanocomposite materials and a substantially transparent film material for suspending the nanocomposite materials, a detector coupled to the three dimensional matrix adapted for detecting a change in the nanocomposite materials, and an analyzer coupled to the detector adapted for analyzing the change detected by the detector. In another embodiment, a method for detecting neutrons includes receiving radiation from a source, converting neutrons in the radiation into alpha particles using converter material, converting the alpha particles into photons using quantum dot emitters, detecting the photons, and analyzing the photons to determine neutrons in the radiation.

  19. An application of CCD read-out technique to neutron distribution measurement using the self-activation method with a CsI scintillator plate

    International Nuclear Information System (INIS)

    Nohtomi, Akihiro; Kurihara, Ryosuke; Kinoshita, Hiroyuki; Honda, Soichiro; Tokunaga, Masaaki; Uno, Heita; Shinsho, Kiyomitsu; Wakabayashi, Genichiro; Koba, Yusuke; Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Ohga, Saiji

    2016-01-01

    In our previous paper, the self-activation of an NaI scintillator had been successfully utilized for detecting photo-neutrons around a high-energy X-ray radiotherapy machine; individual optical pulses from the self-activated scintillator are read-out by photo sensors such as a photomultiplier tube (PMT). In the present work, preliminary observations have been performed in order to apply a direct CCD read-out technique to the self-activation method with a CsI scintillator plate using a Pu-Be source and a 10-MV linac. In conclusion, it has been revealed that the CCD read-out technique is applicable to neutron measurement around a high-energy X-ray radiotherapy machine with the self-activation of a CsI plate. Such application may provide a possibility of novel method for simple neutron dose-distribution measurement. - Highlights: • Preliminary observations have been performed by a CCD for the CsI self-activation method. • It has been revealed that the CCD read-out technique is applicable to neutron measurement. • Such application may provide a novel method for simple neutron distribution measurement.

  20. An application of CCD read-out technique to neutron distribution measurement using the self-activation method with a CsI scintillator plate

    Energy Technology Data Exchange (ETDEWEB)

    Nohtomi, Akihiro, E-mail: nohtomi@hs.med.kyushu-u.ac.jp [Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Kurihara, Ryosuke; Kinoshita, Hiroyuki; Honda, Soichiro; Tokunaga, Masaaki; Uno, Heita [Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Shinsho, Kiyomitsu [Graduate School of Human Sciences, Tokyo Metropolitan University, 7-2-10 Higashi-oku, Arakawa-ku, Tokyo 116-8551 (Japan); Wakabayashi, Genichiro [Atomic Energy Research Institute, Kinki University, 3-4-1 Kowakae, Higashiosaka-shi, Osaka 577-8502 (Japan); Koba, Yusuke [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko [Department of Radiology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Ohga, Saiji [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan)

    2016-10-01

    In our previous paper, the self-activation of an NaI scintillator had been successfully utilized for detecting photo-neutrons around a high-energy X-ray radiotherapy machine; individual optical pulses from the self-activated scintillator are read-out by photo sensors such as a photomultiplier tube (PMT). In the present work, preliminary observations have been performed in order to apply a direct CCD read-out technique to the self-activation method with a CsI scintillator plate using a Pu-Be source and a 10-MV linac. In conclusion, it has been revealed that the CCD read-out technique is applicable to neutron measurement around a high-energy X-ray radiotherapy machine with the self-activation of a CsI plate. Such application may provide a possibility of novel method for simple neutron dose-distribution measurement. - Highlights: • Preliminary observations have been performed by a CCD for the CsI self-activation method. • It has been revealed that the CCD read-out technique is applicable to neutron measurement. • Such application may provide a novel method for simple neutron distribution measurement.

  1. 'aspect' - a new spectrometer for the measurement of the angular correlation coefficient a in neutron beta decay

    CERN Document Server

    Zimmer, O; Grinten, M G D; Heil, W; Glück, F

    2000-01-01

    The combination of the coefficient a of the antineutrino/electron angular correlation with the beta asymmetry of the neutron provides a sensitive test for scalar and tensor contributions to the electroweak Lagrangian, as well as for right-handed currents. A method is given for measuring a with high sensitivity from the proton recoil spectrum. The method is based on a magnetic spectrometer with electrostatic retardation potentials such as used for searches of the neutrino mass in tritium beta decay. The spectrometer can also be used for similar studies using radioactive nuclei.

  2. Light output response of EJ-309 liquid organic scintillator to 2.86-3.95 MeV carbon recoil ions due to neutron elastic and inelastic scatter

    Science.gov (United States)

    Norsworthy, Mark A.; Ruch, Marc L.; Hamel, Michael C.; Clarke, Shaun D.; Hausladen, Paul A.; Pozzi, Sara A.

    2018-03-01

    We present the first measurements of energy-dependent light output from carbon recoils in the liquid organic scintillator EJ-309. For this measurement, neutrons were produced by an associated particle deuterium-tritium generator and scattered by a volume of EJ-309 scintillator into stop detectors positioned at four fixed angles. Carbon recoils in the scintillator were isolated using triple coincidence among the associated particle detector, scatter detector, and stop detectors. The kinematics of elastic and inelastic scatter allowed data collection at eight specific carbon recoil energies between 2.86 and 3.95 MeV. We found the light output caused by carbon recoils in this energy range to be approximately 1.14% of that caused by electrons of the same energy, which is comparable to the values reported for other liquid organic scintillators. A comparison of the number of scattered neutrons at each angle to a Monte Carlo N-Particle eXtended simulation indicates that the ENDF/B-VII.1 evaluation of differential cross sections for 14.1 MeV neutrons on carbon has discrepancies with the experiment as large as 55%, whereas those reported in the JENDL-4.0u evaluation agree with experiment.

  3. Measurement and simulation of neutron response function of organic liquid scintillator detector

    International Nuclear Information System (INIS)

    Gohil, M.; Banerjee, K.; Bhattacharya, S.; Bhattacharya, C.; Kundu, S.; Rana, T.K.; Mukherjee, G.; Meena, J.K.; Pandey, R.; Pai, H.; Ghosh, T.K.; Dey, A.; Mukhopadhyay, S.; Pandit, D.; Pal, S.; Banerjee, S.R.; Bandhopadhyay, T.

    2012-01-01

    Response functions of monoenergetic neutrons at various energies, corresponding to a measured neutron energy spectrum have been extracted. The experimental response functions for neutron energies in the range of ∼2-20 MeV have been compared with the respective GEANT4 predictions. It has been found that, there is some discrepancy between the experimental and the GEANT4 simulated neutron response functions at lower pulse height regions, which increases with the increase of neutron energy. This might be due to the incompleteness of the physics processes used in the present GEANT4 simulations. In particular, higher order reaction processes which become more significant at higher energies should be properly taken into account in the calculation of response function.

  4. The Efficiency of the BC-720 Scintillator in a High-Energy (20--800 MeV) Accelerator Neutron Field

    Energy Technology Data Exchange (ETDEWEB)

    Miles, Leslie H. [Univ. of Missouri, Columbia, MO (United States)

    2005-12-01

    High-energy neutron doses (>20 MeV) are of little importance to most radiation workers. However, space and flight crews, and people working around medical and scientific accelerators receive over half of their radiation dose from high-energy neutrons. Unfortunately, neutrons are difficult to measure, and no suitable dosimetry has yet been developed to measure this radiation. In this paper, basic high-energy neutron interactions, characteristics of high-energy neutron environments, present neutron dosimetry, and quantities used in neutron dosimetry are discussed before looking into the potential of the BC-720 scintillator to improve dosimetry. This research utilized 800 MeV protons impinging upon the WNR Facility spallation neutron source at Los Alamos National Laboratory. Time-of-flight methods and a U-238 Fission Chamber were used to aid evaluation of the efficiency of the BC-720. Results showed that the efficiency is finite over the 20–650 MeV energy region studied, although it decreases by a factor of ten between 40 and 100 MeV. This limits the use of this dosimeter to measure doses at sitespecific locations. It also encourages modifications to use this dosimeter for any unknown neutron field. As such, this dosimeter has the potential for a small, lightweight, real-time dose measurement, which could impact neutron dosimetry in all high-energy neutron environments.

  5. Design and construction of a triple-axis crystal neutron spectrometer and performance testing by means of measurements of dispersion relations in copper

    International Nuclear Information System (INIS)

    Fuhrmann, C.

    1979-01-01

    The Triple-Axis Crystal Neutron Spectrometer is the best instrument for the study of lattice dynamics, when the neutron inelastic scattering technique is used. Design, construction and operation of a triple-axis crystal neutron spectrometer, whose construction was recently finished at IEA are described. The design principles employed are directed to mechanical simplicity, facility of construction and flexibility in operation, with no adapted components to industrial applications were used in the construction. The operational characteristics of the spectrometer, such as the neutron wavelenght of the incoming beam and the resolution have been determined. With the purpose to check the performance of IEA Triple-Axis Crystal Neutron Spectrometer, dispersion relation curves for copper, at room temperature, have been measured. The frequency of phonons propagating along three major symmetry directions have been determined. The measurements were carried out operating the Triple-Axis Spectrometer in the 'sup(→)Q-constant' mode. An excelent agreement could be observed between the results obtained in the present experiment and the data for copper presented in the literature. This comparison indicates that the IEA Triple-Axis Crystal Neutron Spectrometer is in good operational conditions and is able to perform original experiments. Details on the experimental procedures for the case of a Triple-Axis Spectrometer operating in 'sup(→)Q-constant' mode are also presented. (Author) [pt

  6. Neutronics analysis for the ITER core imaging X-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Serikov, Arkady, E-mail: arkady.serikov@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Fischer, Ulrich [Karlsruhe Institute of Technology (KIT), Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Suarez, Alejandro; Barnsley, Robin; Bertalot, Luciano; O’Connor, Richard; Thenevin, Raphaël; Udintsev, Victor S. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2016-11-01

    Highlights: • Proposed substantial radiation shielding design improvements of the CIXS system. • Radiation protection of the CIXS Port Interspace (PI) to provide personnel access. • The SDDR at PI was reduced by 100× from 2 mSv/h to 20 microSv/h. • A screen plate as a temporary shield at the CIXS maintenance period has been proposed. • The shadow effect created by a screen plate reduces SDDR by 9×. - Abstract: This paper presents new results of the MCNP neutronics analysis for the core imaging X-ray spectrometer (CIXS) system of the ITER Equatorial Port Plug #17 (EPP#17). Substantial radiation shielding design improvements of the CIXS system have been suggested as the outcomes of this analysis. These suggested improvements allow reaching two major goals: (1) radiation protection of the CIXS Port Interspace (PI) to provide personnel access for maintenance of the vacuum extension flange; (2) reduction of the neutron and gamma loads on the detectors to reduce the need for maintenance itself. By implementing the improvements in our models such as filling void spaces around the CIXS beams with boron carbide and inserting the tungsten collimators in the narrowed beam channel, we were able to reduce the Shut-Down Dose Rate (SDDR) in the PI by 100× from 2 mSv/h in the original CIXS design to 20 microSv/h. In case of non-changed MCNP geometry, the D1S method was applied in calculations of SDDR. To allow the maintenance access to the flange, a part of shielding was removed, therefore the R2Smesh methodology was applied instead of D1S. During the maintenance access of CIXS from the PI side, a screen plate was proposed to introduce behind which a worker receives much less SDDR.

  7. Development of precise measurement method of neutron energy for plasma temperature diagnostics in thermonuclear fusion

    International Nuclear Information System (INIS)

    Mori, Chizuo; Gotoh, Junichi; Uritani, Akira; Miyahara, Hiroshi; Ikeda, Yuichiro; Kasugai, Yoshimi; Kaneko, Junichi

    1998-01-01

    There are many types of fast neutron spectrometers for plasma temperature diagnostics, 28 Si(n,α) 25 Mg reaction giving the energy resolution of 2.2% for 14 MeV neutrons, the 12 C(n,α) 9 Be reaction giving the resolution of 2.15%. These detectors, however suffer from radiation damage, which demands to exchange the detector to a new one in every a few month depending on the usage. Recoil proton method has also been developed by using liquid scintillator or plastic scintillator, as a neutron-to-proton converter in front of a Si-detector, which is called counter telescope type, giving a resolution of 4.0%. This type of spectrometer can reduce radiation damage by placing Si-detector at outside Neutron beam. The scintillator can measure the lost energy of protons in the converter (i.e. the scintillator) and the measured energy loss can be used for improving the energy resolution. However, the energy resolution of organic scintillator itself is generally not so good. We proposed to use a proportional counter with CH 4 as counting gas and also as a neutron-proton converter, which has far better energy resolution than plastic scintillators, although the time resolution of counting in proportional counters is generally inferior to that in organic scintillation counters. The characteristics of the new spectrometer were experimentally studied and also were simulated with analytical calculation. (author)

  8. High-resolution measurements of the DT neutron spectrum using new CD foils in the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Gatu Johnson, M., E-mail: gatu@psfc.mit.edu; Frenje, J. A.; Li, C. K.; Petrasso, R. D.; Séguin, F. H. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bionta, R. M.; Casey, D. T.; Eckart, M. J.; Grim, G. P.; Hartouni, E. P.; Hatarik, R.; Sayre, D. B.; Skulina, K.; Yeamans, C. B. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Farrell, M. P.; Hoppe, M.; Kilkenny, J. D.; Reynolds, H. G.; Schoff, M. E. [General Atomics, San Diego, California 92186 (United States)

    2016-11-15

    The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility measures the DT neutron spectrum from cryogenically layered inertial confinement fusion implosions. Yield, areal density, apparent ion temperature, and directional fluid flow are inferred from the MRS data. This paper describes recent advances in MRS measurements of the primary peak using new, thinner, reduced-area deuterated plastic (CD) conversion foils. The new foils allow operation of MRS at yields 2 orders of magnitude higher than previously possible, at a resolution down to ∼200 keV FWHM.

  9. The 2.5-MeV neutron time-of-flight spectrometer TOFOR for experiments at JET

    International Nuclear Information System (INIS)

    Gatu Johnson, M.; Giacomelli, L.; Hjalmarsson, A.

    2007-08-01

    A time-of-flight (TOF) spectrometer for measurement of the 2.5-MeV neutron emission from fusion plasmas has been developed and put into use at the JET tokamak. It has been optimized for operation at high rates (TOFOR) for the purpose of performing advanced neutron emission spectroscopy (NES) diagnosis of deuterium plasmas with a focus on the fuel ion motional states for different auxiliary heating scenarios. This requires operation over a large dynamic range including high rates of >100 kHz with a maximum value of 0.5 MHz for the TOFOR design. This paper describes the design principles and their technical realization. The performance is illustrated with recent neutron time-of-flight spectra recorded for plasmas subjected to different heating scenarios. A data acquisition rate of 39 kHz has been achieved at about a tenth of the expected neutron yield limit of JET, giving a projected maximum of 400 kHz at peak JET plasma yield. This means that the count rate capability for NES diagnosis of D plasmas has been improved more than an order of magnitude. Another important performance factor is the spectrometer bandwidth where data have been acquired and analyzed successfully with a response function for neutrons over the energy range 1 to >5 MeV. The implications of instrumental advancement represented by TOFOR are discussed

  10. The 2.5-MeV neutron time-of-flight spectrometer TOFOR for experiments at JET

    International Nuclear Information System (INIS)

    Gatu Johnson, M.; Giacomelli, L.; Hjalmarsson, A.; Kaellne, J.; Weiszflog, M.; Andersson Sunden, E.; Conroy, S.; Ericsson, G.; Hellesen, C.; Ronchi, E.; Sjoestrand, H.; Gorini, G.; Tardocchi, M.; Combo, A.; Cruz, N.; Sousa, J.; Popovichev, S.

    2008-01-01

    A time-of-flight (TOF) spectrometer for measurement of the 2.5-MeV neutron emission from fusion plasmas has been developed and put into use at the JET tokamak. It has been optimized for operation at high rates (TOFOR) for the purpose of performing advanced neutron emission spectroscopy (NES) diagnosis of deuterium plasmas with a focus on the fuel ion motional states for different auxiliary heating scenarios. This requires operation over a large dynamic range, including high rates of >100 kHz with a maximum value of 0.5 MHz for the TOFOR design. This paper describes the design principles and their technical realization. The performance is illustrated with recent neutron TOF spectra recorded for plasmas subjected to different heating scenarios. A true event count rate of 39 kHz has been achieved at about a tenth of the expected neutron yield limit of JET, giving a projected maximum of 400 kHz at peak JET plasma yield. This means that the count rate capability for NES diagnosis of D plasmas has been improved more than an order of magnitude. Another important performance factor is the spectrometer bandwidth, where data have been acquired and analyzed successfully with a response function for neutrons over the energy range 1 to >5 MeV. The implications of instrumental advancement represented by TOFOR are discussed

  11. The 2.5-MeV neutron time-of-flight spectrometer TOFOR for experiments at JET

    Energy Technology Data Exchange (ETDEWEB)

    Gatu Johnson, M.; Giacomelli, L.; Hjalmarsson, A. (and others)

    2007-08-15

    A time-of-flight (TOF) spectrometer for measurement of the 2.5-MeV neutron emission from fusion plasmas has been developed and put into use at the JET tokamak. It has been optimized for operation at high rates (TOFOR) for the purpose of performing advanced neutron emission spectroscopy (NES) diagnosis of deuterium plasmas with a focus on the fuel ion motional states for different auxiliary heating scenarios. This requires operation over a large dynamic range including high rates of >100 kHz with a maximum value of 0.5 MHz for the TOFOR design. This paper describes the design principles and their technical realization. The performance is illustrated with recent neutron time-of-flight spectra recorded for plasmas subjected to different heating scenarios. A data acquisition rate of 39 kHz has been achieved at about a tenth of the expected neutron yield limit of JET, giving a projected maximum of 400 kHz at peak JET plasma yield. This means that the count rate capability for NES diagnosis of D plasmas has been improved more than an order of magnitude. Another important performance factor is the spectrometer bandwidth where data have been acquired and analyzed successfully with a response function for neutrons over the energy range 1 to >5 MeV. The implications of instrumental advancement represented by TOFOR are discussed.

  12. New components for the neutron spectrometer SV5c at the 10H channel of the research reactor FRJ2

    International Nuclear Information System (INIS)

    Stockmeyer, R.

    1991-02-01

    The following new components have been installed at the neutron time-of-flight spectrometer SV5c: 1. Monochromator with devices for tilting and rotating 10 crystal. The fine-adjustment of the crystal orientation can be done with a computer program which maximizes the neutron intensity at the sample position. 2. 128 x 512 multi-channel time-of-flight electronic 3. Computerized equipment for measuring thermal properties of a sample (adsorption isotherm, sample transmission) 4. Data aquisition, data handling and experiment control software coded in ASYST. (orig.)

  13. Neutron spectrometry for D-T plasmas in JET, using a tandem annular-radiator proton-recoil spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Hawkes, N.P.; Bond, D.S.; Kiptily, V.; Jarvis, O.N. E-mail: onj@jet.uk; Conroy, S.W

    2002-01-01

    A selection of the 14-MeV neutron spectra obtained at the JET Joint Undertaking tokamak during the deuterium-tritium operating campaign in 1997 are presented and analyzed. While several neutron spectrometers were operational during this campaign, the present paper is concerned solely with one: the tandem annular-radiator proton-recoil spectrometer (or proton recoil telescope, for brevity). During neutral beam heating with combined d- and t-beams, analysis of the spectra can define the core fuel composition (D:T) ratio. The spectra are sensitive to the population balance of the fast ions streaming in directions parallel and opposite to that of the injected beams. During ICRF heating of minority deuterium in bulk tritium plasmas, the spectra provide measurements of the effective temperature of the fast-deuteron energy tail and of its relative strength, which vary with the deuterium concentration. This information contributes to the overall understanding of the fusion performance of the various operating scenarios.

  14. A Comprehensive Study on Gamma Rays and Fast Neutron Sensing Properties of GAGOC and CMO Scintillators for Shielding Radiation Applications

    Directory of Open Access Journals (Sweden)

    Shams A. M. Issa

    2017-01-01

    Full Text Available The WinXCom program has been used to calculate the mass attenuation coefficients (μm, effective atomic numbers (Zeff, effective electron densities (Nel, half-value layer (HVL, and mean free path (MFP in the energy range 1 keV–100 GeV for Gd3Al2Ga3O12Ce (GAGOC and CaMoO4 (CMO scintillator materials. The geometrical progression (G-P method has been used to compute the exposure buildup factors (EBF and gamma ray energy absorption (EABF in the photon energy range 0.015–15 MeV and up to a 40 penetration depth (mfp. In addition, the values of the removal cross section for a fast neutron ∑R have been calculated. The computed data observes that GAGOC showed excellent γ-rays and neutrons sensing a response in the broad energy range. This work could be useful for nuclear radiation sensors, detectors, nuclear medicine applications (medical imaging and mammography, nuclear engineering, and space technology.

  15. Data recording programme for a time-of-flight neutron spectrometer

    International Nuclear Information System (INIS)

    Smit, J.G.

    1975-04-01

    A modular program was written for the acquisition of the measurement data of a rotating crystal neutron spectrometer in a PDP-11/20 computer (16 K core memory). The modules are subroutines called by the higher-order FORTRAN programs. This program, which is carried out under the version 08/02 disk operating system, collects the data of a maximum number of 7 detectors in the core memory via interrupts in the on line mode. The detectors are connected to a time-of-flight unit which assigns the time and the detector number to the signals (minimum width of time channel 0.5 μs). From the T.O.F. unit the signals are passed on to the computer via a CAMAC input register and the CA-11 a branch driver manufactured by DEC. All the measurement data can be graphically displayed on a Tektronix visual display unit (keyboard interrupt). Relevant data are stored on disk and passed on to the central computer (S 4004) for further processing at the end of the experiment. (orig./RF) [de

  16. Response matrix of an extended range Bonner sphere spectrometer for the characterization of collimated neutron beams

    International Nuclear Information System (INIS)

    Bedogni, R.; Esposito, A.; Gomez-Ros, J.M.

    2010-01-01

    Accelerator-based neutron beams are becoming popular tools for material testing, radiation hardness and soft errors studies. The characterization of these beams in terms of dosimetric and spectrometric quantities is a challenging task, mainly due to their wide energy interval (from thermal up to hundreds MeV) and, in certain facilities like VESUVIO - ISIS (RAL, UK), to their small dimension (few cm in radius). Extended Range Bonner Sphere Spectrometers (ERBSS) would be a valuable tool, due to their wide energy range, good photon discrimination and possibility to choose among different central detectors according to the intensity, photon component and time structure of the field. Nevertheless, the non-uniform irradiation of the spheres could lead to important systematic errors. With the aim of bringing the advantages of ERBSS into the characterization of collimated beams, a dedicated study was performed using the VESUVIO spallation-based collimated beam at ISIS (Rutherford Appleton Laboratory, Oxford). Here a 3.21 cm radius collimated beam was characterized using a Dysprosium activation foil-based ERBSS whose response matrix was recalculated for this specific beam diameter. Besides the results of the experimental campaign, this paper presents the calculation of the response matrix and its dependence on the beam dimension.

  17. Shape difference between scintillation pulses due to γ rays and to neutrons

    International Nuclear Information System (INIS)

    Cambou, Francis; Ambrosino, Georges

    1960-01-01

    A simple method is described which allows to clearly show the shape differences between γ ray- and neutron-induced pulses. In the neutrons case the intensity of the slow component is 2.4 times higher than in the γ ray case. Reprint of a paper published in Comptes rendus des seances de l'Academie des Sciences, t. 250, p. 1034-1036, sitting of 8 February 1960 [fr

  18. The multianalyser system of the three axes neutron spectrometer PUMA: Pilot experiments with the innovative multiplex technique

    Energy Technology Data Exchange (ETDEWEB)

    Sobolev, Oleg; Hoffmann, Ron; Gibhardt, Holger [Institute for Physical Chemistry, Georg-August-University of Göttingen, Tammannstr. 6, D-37077 Göttingen (Germany); Jünke, Norbert [Forschungs-Neutronenquelle Heinz-Maier-Leibnitz, Technical University of Munich, Lichtenbergstr. 1, D-85748 Garching (Germany); Knorr, Andreas; Meyer, Volker [Institute for Physical Chemistry, Georg-August-University of Göttingen, Tammannstr. 6, D-37077 Göttingen (Germany); Eckold, Götz, E-mail: geckold@gwdg.de [Institute for Physical Chemistry, Georg-August-University of Göttingen, Tammannstr. 6, D-37077 Göttingen (Germany)

    2015-02-01

    A new type of multiplex technique for three axes neutron spectrometers has been realized and successfully commissioned at the PUMA spectrometer at FRM II. Consisting of eleven analyser-detector channels which can be configured individually, this technique is especially suitable for kinetic experiments where a single excitation spectrum is recorded as a function of time without the need to move the spectrometer. On a time-scale of seconds an entire spectrum can be recorded thus allowing users to monitor changes during fast kinetic processes in single shot experiments without the need for stroboscopic techniques. Moreover, the multianalyser system provides an efficient and rapid tool for mapping excitations in (Q,ω)-space. The results of pilot experiments demonstrate the performance of this new technique and a user-friendly software is presented which assists users during their experiments.

  19. Characterization of the neutron field at the ISIS-VESUVIO facility by means of a bonner sphere spectrometer

    Science.gov (United States)

    Bedogni, Roberto; Esposito, Adolfo; Andreani, Carla; Senesi, Roberto; De Pascale, Maria Pia; Picozza, Piergiorgio; Pietropaolo, Antonino; Gorini, Giuseppe; Frost, Christopher D.; Ansell, Stewart

    2009-12-01

    One of the more actual and promising fields of applied neutron physics is the investigation of the malfunctions induced by high-energy neutrons naturally present in the atmosphere in electronic devices, called single event effects (SEE). These studies are of primary importance for the design of devices that have to fulfill high reliability requirements and those that are likely to be exposed to enhanced levels of cosmic rays background, e.g. in aerospace and avionic applications. Particle accelerators-driven neutron sources constitute valuable irradiation facilities for these purposes as they provide an opportunity for accelerated testing of the effects of these naturally occurring neutrons, provided the neutron spectrum is comparable with the atmospheric one and the neutron fields are known with high accuracy. The latter can be achieved through the use of appropriate radiation transport codes and neutron spectrometry techniques. In view of the design and construction of CHIPIR, a dedicated beam line for SEE studies at the ISIS pulsed neutron source second target station (UK) [1] ( http://ts-2.isis.rl.ac.uk/instruments/phase2/index.htm), a spectrometric characterization was performed on the VESUVIO beamline [2] (Senesi et al.,2000). The spectrometric technique was the bonner sphere spectrometer (BSS), widely used to determine neutron spectra and dose quantities around high-energy accelerators. The experimental campaign provided a complete spectrometric investigation of the VESUVIO neutron beam, allowing the integral quantities (total fluence rate, fraction of fluence in given energy intervals) to be estimated with uncertainties lower than 10%.

  20. Conceptual design and optimization of a plastic scintillator array for 2D tomography using a compact D-D fast neutron generator.

    Science.gov (United States)

    Adams, Robert; Zboray, Robert; Cortesi, Marco; Prasser, Horst-Michael

    2014-04-01

    A conceptual design optimization of a fast neutron tomography system was performed. The system is based on a compact deuterium-deuterium fast neutron generator and an arc-shaped array of individual neutron detectors. The array functions as a position sensitive one-dimensional detector allowing tomographic reconstruction of a two-dimensional cross section of an object up to 10 cm across. Each individual detector is to be optically isolated and consists of a plastic scintillator and a Silicon Photomultiplier for measuring light produced by recoil protons. A deterministic geometry-based model and a series of Monte Carlo simulations were used to optimize the design geometry parameters affecting the reconstructed image resolution. From this, it is expected that with an array of 100 detectors a reconstructed image resolution of ~1.5mm can be obtained. Other simulations were performed in order to optimize the scintillator depth (length along the neutron path) such that the best ratio of direct to scattered neutron counts is achieved. This resulted in a depth of 6-8 cm and an expected detection efficiency of 33-37%. Based on current operational capabilities of a prototype neutron generator being developed at the Paul Scherrer Institute, planned implementation of this detector array design should allow reconstructed tomograms to be obtained with exposure times on the order of a few hours. Copyright © 2014 Elsevier Ltd. All rights reserved.