WorldWideScience

Sample records for neutron multisphere spectrometer

  1. 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

  2. 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, ...

  3. 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

  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. 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...

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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, ...

  12. Neutron reference spectra measurements with the Bonner multi-spheres spectrometer; Medidas de espectros de referencia de neutrons com o espectrometro de multiesferas de Bonner

    Energy Technology Data Exchange (ETDEWEB)

    Lemos Junior, Roberto Mendonca de

    2004-07-01

    This paper aims to define a procedure to use the Bonner Multisphere Spectrometer with a {sup 6}LiI(Eu) detector in order to determine of neutron spectra. It was measured {sup 238}PuBe spectra and same of reference ({sup 241}AmBe, {sup 252}Cf e {sup 252}Cf+D{sub 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 {sup 241}AmBe source was 122 {+-} 4 {mu}Sv/h with 7% of uncertainty and 95% of confidence level. The procedure established in this work was tested with the {sup 238}PuBe spectrum, obtaining an environment dose equivalent rate of 286 {+-} 9 {mu}Sv/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

  13. Upgrade of the PNNL TEPC and Multisphere Spectrometer

    International Nuclear Information System (INIS)

    Scherpelz, Robert I.; Conrady, Matthew M.

    2008-01-01

    The Pacific Northwest National Laboratory (PNNL) has used two types of instruments, the tissue equivalent proportional counter (TEPC) and the multisphere spectrometer for characterizing neutron radiation fields in support of neutron dosimetry at the Hanford site. The US Department of Energy recently issued new requirements for radiation protection standards in 10 CFR 835 which affect the way that neutron dose equivalent rates are evaluated. In response to the new requirements, PNNL has upgraded the analyses used in conjunction with the TEPC and multisphere. The analysis software for the TEPC was modified for this effort, and a new analysis code was selected for the multisphere. These new analysis techniques were implemented and tested with measurement data that had been collected in previous measurements. In order to test the effectiveness of the changes, measurements were taken in PNNL's Low Scatter Room using 252Cf sources in both unmoderated and D2O-moderated configurations that generate well-characterized neutron fields. The instruments were also used at Los Alamos National Laboratory (LANL), in their Neutron Free-in-Air calibration room, also using neutron sources that generate well-characterized neutron fields. The results of the software modifications and the measurements are documented in this report. The TEPC measurements performed at PNNL agreed well with accepted dose equivalent rates using the traditional analysis, agreeing with the accepted value to within 13% for both unmoderated and moderated 252Cf sources. When the new analysis was applied to the TEPC measurement data, the results were high compared to the new accepted value. A similar pattern was seen for TEPC measurements at LANL. Using the traditional analysis method, results for all neutron sources showed good agreement with accepted values, nearly always less than 10%. For the new method of analysis, however, the TEPC responded with higher dose equivalent rates than accepted, by as much as 25

  14. Calibration of a spectrometry multisphere system for neutron fields

    International Nuclear Information System (INIS)

    Carelli, Jorge L.; Cruzate, Juan A.; Papadopulos, Susana B.; Gregori, Beatriz N.; Ciocci Brazzano, Ligia

    2005-01-01

    In this work it is presented the calibration of the neutrons spectrometric system of the Nuclear Regulatory Authority (ARN) in the Institut de Protection et Sure te Nucleaires (Ipn), Labourite dadaist et de Recherche s en Dosimetric Extern e, Cadarache, France. The multisphere system is composed of 9 polyethylene spheres of high density, with a gaseous detector of 3 He and associate electronics. The matrix of energy response to the system neutrons was obtained applying the MCNPX code for the range of energies between thermal and 100 MeV with cross sections taken from library ENDF/B-VI. The neutron spectra of the multisphere system were obtained applying the deconvolution code LOUHI82. The relationship between the theoretical responses and the experiences obtained with the AmBe and 252 Cf sources are also presented in this work [es

  15. Study of reproducibility of measurements with the spectrometer of Bonner multispheres

    International Nuclear Information System (INIS)

    Azevedo, G.A.; Pereira, W.W.; Patrao, K.C.S.; Fonseca, E.S.

    2013-01-01

    This work aims to study the metrological behavior of the Bonner Multisphere Spectrometer (BMS) of the LN / LNMRI / IRD - Laboratorio Metrologia de Neutrons / Laboratorio Nacional de Metrologia e Radiacao Ionizante / Instituto de Radioprotecao e Dosimetria, for measurements in repeatability and reproducibility conditions. Initially, a simulation was done by applying the Monte Carlo method, using the MCNP code and respecting the ISO 8529-1 (2001), using the sources of Californium ( 252 Cf), Americium-Beryllium ( 241 AmBe) and californium in heavy water (Cf + D 2 O), all located at a distance of 100 cm from the neutron detector ( 6 Li (Eu) - crystal scintillator). In this program, the counting of neutrons that are captured by the detector was made. The source is located in the center of a sphere of radius 300 cm. Analyzes the impact of these neutrons in a point of the sphere wall, which in this case acted as a neutron detector and from there, it is estimated the number of neutrons that collide in the whole sphere. The purpose is to obtain the neutron count for different energy bands in a solid field of neutrons, since they have a spectrum ranging from a low to a high energy that can also vary within a particular environment. Wishes to obtain new fields with different sources and moderators materials to be used as new reference fields. Measurements are being conducted for these fields, with the aim of analyzing the variability conditions of the measurement (repeatability and reproducibility) in LEN - Laboratorio de Espectrometria de Neutrons of the LN/LMNRI/IRD. Thus, the spectrometer will be used to improve both the knowledge of the spectrum as the standard of neutrons of the lab, proving that a spectrometry is essential for correct measurement

  16. Multisphere system neutron spectrometry applied to dosimetry for the personnel

    International Nuclear Information System (INIS)

    Allinei, P.G.

    1992-01-01

    Neutron dosimetry is a necessity that must be dealt with in order to ensure efficient monitoring of all personnel regarding radiology safety. Dosimetric variables are difficult to measure for they are dependent on complex functions evolving with the energy of neutrons, which forces us to determine their energetic distribution. We have chosen to use the multisphere system associated to an unfolding code in order to perform neutron spectrometry, our purpose being to determine these dosimetric variables. The initial stage consists in modifying a research code, the code SOHO, in order to adapt it to our needs. The resulting new version was subsequently tested and proven successful by means of computerized simulations. Afterwards, we used reference dosimetric and spectral beams to confirm the position results previously obtained. At the time of this test, the code SOHO yielded results coherent with the theoretical values, and even allowed the quantity of radiation diffused by the laboratory structures to be estimated. The final part of this study consists in applying the previously perfected technique to authentic situations. The results thus obtained are compared to those obtained by conventional methods in order to reveal the interest of neutron spectrometry used for dosimetry of the personnel

  17. FRUIT: An operational tool for multisphere neutron spectrometry in workplaces

    International Nuclear Information System (INIS)

    Bedogni, Roberto; Domingo, Carles; Esposito, Adolfo; Fernandez, Francisco

    2007-01-01

    FRUIT (Frascati Unfolding Interactive Tool) is an unfolding code for Bonner sphere spectrometers (BSS) developed, under the Labview environment, at the INFN-Frascati National Laboratory. It models a generic neutron spectrum as the superposition of up to four components (thermal, epithermal, fast and high energy), fully defined by up to seven positive parameters. Different physical models are available to unfold the sphere counts, covering the majority of the neutron spectra encountered in workplaces. The iterative algorithm uses Monte Carlo methods to vary the parameters and derive the final spectrum as limit of a succession of spectra fulfilling the established convergence criteria. Uncertainties on the final results are evaluated taking into consideration the different sources of uncertainty affecting the input data. Relevant features of FRUIT are (1) a high level of interactivity, allowing the user to follow the convergence process, (2) the possibility to modify the convergence tolerances during the run, allowing a rapid achievement of meaningful solutions and (3) the reduced dependence of the results from the initial hypothesis. This provides a useful instrument for spectrometric measurements in workplaces, where detailed a priori information is usually unavailable. This paper describes the characteristics of the code and presents the results of performance tests over a significant variety of reference and workplace neutron spectra ranging from thermal up to hundreds MeV neutrons

  18. 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)

  19. 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

  20. Measurement of the neutron spectrum in a room with an accelerator Varian 2300C/D Linac using the Bonner multisphere spectrometer; Medicao do espectro de neutrons em uma sala com um acelerador Varian 2300C/D Linav usando o espectrometro de multiesferas de Bonner

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcante, D.B.S., E-mail: cavalcante@ird.gov.b [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica; Fonseca, E.S. da, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lemos Junior, R.M. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil); Batista, D.V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The generated neutron field varies considerably and depends on the beam energy, on the shielding of the accelerator, on the filters for beam homogeneity, and also on the mobile collimators and geometry of irradiation. The estimation of the component relative to the photoneutrons has practical interest for evaluation of the radiological risks for the workers and for the patient as well. Due to the high frequency magnetic field, and to the photon abundance resulting of the escape and scattering at treatment room, those measurements present some difficulties. Measurements of the neutron fields can be made with a Bonner spectrometer. Those system was calibrated with referred neutron standard sources and used for make measurements on a spot of the room where a Variant 2300C/D Linac is installed. The unfolding process used the BUNKI computer code for determination of the neutron spectra at the measurement spot

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Project 252Cf-D2O. The multisphere system of neutron dosimetry and spectrometry (M.S.-N.D.S.). Studies of applications to health physics

    International Nuclear Information System (INIS)

    Zaborowski, H.L.

    1976-10-01

    The project 252 Cf-D 2 O is articulated upon the utilization of a 200μg nominal 252 Cf spontaneous neutron fission source, used bare and under D 2 O spherical moderators, giving leakage neutron spectra experimentally known and/or calculated. This project has for objective the applications of those sources to Health Physics, in dosimetry (calibration of ''rad'' and ''rem-meters'') and in spectrometry, associated with the experimental system of measurements made by the generalization of the BONNER Spheres, known as ''the Multisphere System''. This communication describes the normalization method used and the results obtained leading to the adoption of a reference matrix called ''the Log-Normal Multisphere Matrix'' (LN-MM) giving the energies response functions of the generalized system for all the spheres diameters between 40 and 400 millimeters and for all the energies between 0.4eV and 15MeV [fr

  6. Neutron detection time distributions of multisphere LiI detectors and AB rem meter at a 20 MeV electron linac

    International Nuclear Information System (INIS)

    Liu, J.C.; Rokni, S.; Vylet, V.; Arora, R.; Semones, E.; Justus, A.

    1997-01-01

    Neutron detection time distribution is an important factor for the dead-time correction for moderator type neutron detectors used in pulsed radiation fields. Measurements of the neutron detection time distributions of multisphere LiL detectors (2''3'' , 5'', 8'', 10'' and 12'' in diameter) and an AB rem meter were made inside an ANL 20 MeV electron linac room. Calculations of the neutron detection time distributions were also made using Monte Carlo codes. The first step was to calculate the neutron energy spectra at the target and detector positions, using a coupled EGS4-MORSE code with a giant-resonant photoneutron generation scheme. The calculated detector spectrum was found in agreement with the multisphere measurements. Then, neutrons hitting the detector surface were scored as a function of energy and the travel time in the room using MCNP. Finally, the above neutron fluence as a function of energy and travel time was used as the source term, and the neutrons detected by 6 Li or 10 B in the sensor were scored as a function of detection time for each detector using MCNP. The calculations of the detection time distributions agree with the measurements. The results also show that the detection time distributions of detectors with large moderators depend mainly on the moderator thickness and neutron spectrum. However, for small detectors, the neutron travel time in the field is also crucial. Therefore, all four factors (neutron spectrum, neutron travel time in the field, detector moderator thickness and detector response function) may play inter-related roles in the detection time distribution of moderator type detectors. (Author)

  7. 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.

  8. A diffusion-theoretical method to calculate the neutron flux distribution in multisphere configurations

    International Nuclear Information System (INIS)

    Schuerrer, F.

    1980-01-01

    For characterizing heterogene configurations of pebble-bed reactors the fine structure of the flux distribution as well as the determination of the macroscopic neutronphysical quantities are of interest. When calculating system parameters of Wigner-Seitz-cells the usual codes for neutron spectra calculation always neglect the modulation of the neutron flux by the influence of neighbouring spheres. To judge the error arising from that procedure it is necessary to determinate the flux distribution in the surrounding of a spherical fuel element. In the present paper an approximation method to calculate the flux distribution in the two-sphere model is developed. This method is based on the exactly solvable problem of the flux determination of a point source of neutrons in an infinite medium, which contains a spherical perturbation zone eccentric to the point source. An iteration method allows by superposing secondary fields and alternately satisfying the conditions of continuity on the surface of each of the two fuel elements to advance to continually improving approximations. (orig.) 891 RW/orig. 892 CKA [de

  9. 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

  10. 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)

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.)

  19. 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.

  20. 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.

  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. 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.

  3. 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.

  4. 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)

  5. 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

  6. 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

  7. Neutron Measurements At Hanford's Plutonium Finishing Plant

    International Nuclear Information System (INIS)

    Conrady, Matthew M.; Berg, Randal K.; Scherpelz, Robert I.; Rathbone, Bruce A.

    2009-01-01

    The Pacific Northwest National Laboratory (PNNL) conducted neutron measurements at Hanford's Plutonium Finishing Plant (PFP). The measurements were performed to evaluate the performance of the Hanford Standard Dosimeter (HSD) and the 8816 TLD component of the Hanford Combination Neutron Dosimeter (HCND) in the neutron fields responsible for worker neutron exposures. For this study, TEPC detectors and multisphere spectrometers were used to measure neutron dose equivalent rate, and multispheres were used to measure average neutron energy. Water-filled phantoms holding Hanford dosimeters were positioned at each measurement location. The phantoms were positioned in the same location where a multisphere measurement was taken and TEPCs were also positioned there. Plant survey meters were also used to measure neutron dose rates at all locations. Three measurement locations were chose near the HC-9B glovebox in room 228A of Building 234-5. The multisphere spectrometers measured average neutron energies in the range of 337 to 555 keV at these locations. Personal dose equivalent, Hp(10)n, as measured by the multisphere and TEPC, ranged from 2.7 to 9.7 mrem/h in the three locations. Effective dose assuming a rotational geometry (EROT) was substantially lower than Hp(10), ranging from 1.3 to 3.6 mrem/h. These values were lower than the reported values from dosimeters exposed on a rotating phantom. Effective dose assuming an AP geometry (EAP) was also substantially lower than Hp(10), ranging from 2.3 to 6.5 mrem/h. These values were lower than the reported values from the dosimeters on slab phantoms. Since the effective dose values were lower than reported values from dosimeters, the dosimeters were shown to be conservative estimates of the protection quantities.

  8. 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

  9. 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.)

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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)

  16. 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.)

  17. 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...

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. The multi-sphere technique. 1 - general characteristics and applications; La technique multisphere. 1 - caracteristiques generales et applications

    Energy Technology Data Exchange (ETDEWEB)

    Zaborcwski, H [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1965-07-01

    A study is made of the general characteristics and the applications of the multisphere technique for flux measurements, dosimetry and the spectrometry of neutron sources ranging from thermal, up to 7 MeV neutrons. We give the equations relating to three fluxmeters (proportional long counters) for the measurements of the flux. Other equations have been derived : 1 - for multi-collision rad and rem dosimetry and first collision rad dosimetry; 2 - for the spectrometry and dosimetry of neutrons in five energy bands using a method similar to that used by threshold detectors. (author) [French] Nous etudions les caracteristiques generales et les applications de la technique multisphere pour les mesures de flux, la dosimetrie et la spectrometrie des sources de neutrons depuis les thermiques jusqu'a 7 MeV. Nous donnons les equations relatives a trois fluxmetres (longs compteurs equivalents) pour les mesures en flux. D'autres equations ont ete derivees: 1 - pour la dosimetrie en rad et en rem de multicollision et en rad de premiere collision; 2 - pour la spectrometrie et la dosimetrie des neutrons en cinq bandes energetiques suivant une methode voisine de celle utilisee par detecteurs a seuil. (auteur)

  7. 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)

  8. 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.

  9. 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

  10. 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.

  11. 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)

  12. 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)

  13. 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)

  14. 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

  15. 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

  16. Uncertainties related to numerical methods for neutron spectra unfolding

    International Nuclear Information System (INIS)

    Glodic, S.; Ninkovic, M.; Adarougi, N.A.

    1987-10-01

    One of the often used techniques for neutron detection in radiation protection utilities is the Bonner multisphere spectrometer. Besides its advantages and universal applicability for evaluating integral parameters of neutron fields in health physics practices, the outstanding problems of the method are data analysis and the accuracy of the results. This paper briefly discusses some numerical problems related to neutron spectra unfolding, such as uncertainty of the response matrix as a source of error, and the possibility of real time data reduction using spectrometers. (author)

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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)

  3. 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

  4. 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...

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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...

  10. 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)

  11. 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)

  12. 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

  13. 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...

  14. 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.

  15. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  16. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  17. 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.

  18. 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

  19. 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.

  20. 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)

  1. 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

  2. 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

  3. 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.

  4. Neutron dose and energy spectra measurements at Savannah River Plant

    International Nuclear Information System (INIS)

    Brackenbush, L.W.; Soldat, K.L.; Haggard, D.L.; Faust, L.G.; Tomeraasen, P.L.

    1987-08-01

    Because some workers have a high potential for significant neutron exposure, the Savannah River Plant (SRP) contracted with Pacific Northwest Laboratory (PNL) to verify the accuracy of neutron dosimetry at the plant. Energy spectrum and neutron dose measurements were made at the SRP calibrations laboratory and at several other locations. The energy spectra measurements were made using multisphere or Bonner sphere spectrometers, 3 He spectrometers, and NE-213 liquid scintillator spectrometers. Neutron dose equivalent determinations were made using these instruments and others specifically designed to determine dose equivalent, such as the tissue equivalent proportional counter (TEPC). Survey instruments, such as the Eberline PNR-4, and the thermoluminescent dosimeter (TLD)-albedo and track etch dosimeters (TEDs) were also used. The TEPC, subjectively judged to provide the most accurate estimation of true dose equivalent, was used as the reference for comparison with other devices. 29 refs., 43 figs., 13 tabs

  5. 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.)

  6. 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.,

  7. 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.)

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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)

  13. Neutron and gamma-ray spectra of {sup 239}PuBe and {sup 241}AmBe

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Carrillo, H.R. E-mail: rvega@cantera.reduaz.mx; Manzanares-Acuna, Eduardo; Becerra-Ferreiro, A.M.; Carrillo-Nunez, Aureliano

    2002-08-01

    Neutron and gamma-ray spectra of {sup 239}PuBe and {sup 241}AmBe were measured and their dosimetric features were calculated. Neutron spectra were measured using a multisphere neutron spectrometer with a {sup 6}LiI(Eu) scintillator. The {sup 239}PuBe neutron spectrum was measured in an open environment, while the {sup 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 {sup 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.

  14. 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.

  15. 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)

  16. 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

  17. 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%.

  18. 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.)

  19. 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

  20. 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)

  1. 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

  2. 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)

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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...

  8. 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

  9. 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

  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. 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

  12. 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...

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. 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)

  1. 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)

  2. 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

  3. 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

  4. Neutron spectra produced by moderating an isotopic neutron source

    International Nuclear Information System (INIS)

    Carrillo Nunnez, Aureliano; Vega Carrillo, Hector Rene

    2001-01-01

    A Monte Carlo study has been carried out to determine the neutron spectra produced by an isotopic neutron source inserted in moderating media. Most devices used for radiation protection have a response strongly dependent on neutron energy. ISO recommends several neutron sources and monoenergetic neutron radiations, but actual working situations have broad spectral neutron distributions extending from thermal to MeV energies, for instance, near nuclear power plants, medical applications accelerators and cosmic neutrons. To improve the evaluation of the dosimetric quantities, is recommended to calibrate the radiation protection devices in neutron spectra which are nearly like those met in practice. In order to complete the range of neutron calibrating sources, it seems useful to develop several wide spectral distributions representative of typical spectra down to thermal energies. The aim of this investigation was to use an isotopic neutron source in different moderating media to reproduce some of the neutron fields found in practice. MCNP code has been used during calculations, in these a 239PuBe neutron source was inserted in H2O, D2O and polyethylene moderators. Moderators were modeled as spheres and cylinders of different sizes. In the case of cylindrical geometry the anisotropy of resulting neutron spectra was calculated from 0 to 2 . From neutron spectra dosimetric features were calculated. MCNP calculations were validated by measuring the neutron spectra of a 239PuBe neutron source inserted in a H2O cylindrical moderator. The measurements were carried out with a multisphere neutron spectrometer with a 6LiI(Eu) scintillator. From the measurements the neutron spectrum was unfolded using the BUNKIUT code and the UTA4 response matrix. Some of the moderators with the source produce a neutron spectrum close to spectra found in actual applications, then can be used during the calibration of radiation protection devices

  5. 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)

  6. 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.

  7. 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)

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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)

  13. 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.

  14. 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

  15. 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%

  16. 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...

  17. 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)

  18. 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.

  19. 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

  20. 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...

  1. 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...

  2. 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)

  3. 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.

  4. 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

  5. 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.

  6. 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)

  7. 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.)

  8. 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.

  9. 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.)

  10. 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.

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  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. 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.

  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. 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

  5. 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.)

  6. 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)

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.)

  4. 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.)

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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)

  16. 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.

  17. 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).

  18. 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).

  19. 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).

  20. Measurement of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 high-altitude airplane

    CERN Document Server

    Goldhagen, P E; Kniss, T; Reginatto, M; Singleterry, R C; Van Steveninck, W; Wilson, J W

    2002-01-01

    Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial aircraft flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the atmospheric ionizing radiation (AIR) project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on five flights of a NASA ER-2 high-altitude aircraft. The primary AIR instrument was a highly sensitive extended-energy multisphere neutron spectrometer with lead and steel shells placed within the moderators of two of its 14 detectors to enhance response at high energies. Detector responses were calculated for neutrons and charged hadrons at energies up to 100 GeV using MCNPX. Neutron spectra were unfolded from the measured count rates using the new MAXED code. We have measured the cosmic-ray neutron spectrum (t...

  1. 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

  2. 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.

  3. 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.

  4. 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)

  5. 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

  6. 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

  7. 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

  8. 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.)

  9. 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.

  10. Characteristics of thermal neutron calibration fields using a graphite pile

    International Nuclear Information System (INIS)

    Uchita, Yoshiaki; Saegusa, Jun; Kajimoto, Yoichi; Tanimura, Yoshihiko; Shimizu, Shigeru; Yoshizawa, Michio

    2005-03-01

    The Facility of Radiation Standards of Japan Atomic Energy Research Institute is equipped with thermal neutron fields for calibrating area and personal neutron dosemeters. The fields use moderated neutrons leaked from a graphite pile in which radionuclide sources are placed. In January 2003, we have renewed the pile with some modifications in its size. In accordance with the renewal, we measured and calculated thermal neutron fluence rates, neutron energy distributions and angular distributions of the fields. The thermal neutron fluence rates of the ''inside-pile fields'' and the outside-pile fields'' were determined by the gold foil activation method. The neutron energy distributions of the outside-pile fields were also measured with the Bonner multi-sphere spectrometer system. The contributions of epithermal and fast neutrons to the total dose-equivalents were 9% in the southern outside-pile field and 12% in the western outside-pile field. The personal dose-equivalents, H p,slab (10, α), in the outside-pile fields are evaluated by considering the calculated angular distributions of incoming neutrons. The H p,slab (10, α) was found to be about 40% higher than the value in assuming the unidirectional neutron between the pile and the test point. (author)

  11. 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)

  12. 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.

  13. Response matrix calculation of a Bonner Sphere Spectrometer using ENDF/B-VII libraries

    Energy Technology Data Exchange (ETDEWEB)

    Morató, Sergio; Juste, Belén; Miró, Rafael; Verdú, Gumersindo [Instituto de Seguridad Industrial, Radiofísica y Medioambiental (ISIRYM), Universitat Politècnica de València (Spain); Guardia, Vicent, E-mail: bejusvi@iqn.upv.es [GD Energy Services, Valencia (Spain). Grupo dominguis

    2017-07-01

    The present work is focused on the reconstruction of a neutron spectra using a multisphere spectrometer also called Bonner Spheres System (BSS). To that, the determination of the response detector curves is necessary therefore we have obtained the response matrix of a neutron detector by Monte Carlo (MC) simulation with MCNP6 where the use of unstructured mesh geometries is introduced as a novelty. The aim of these curves was to study the theoretical response of a widespread neutron spectrometer exposed to neutron radiation. A neutron detector device has been used in this work which is formed by a multispheres spectrometer (BSS) that uses 6 high density polyethylene spheres with different diameters. The BSS consists of a set of 0.95 g/cm{sup 3} high density polyethylene spheres. The detector is composed of a lithium iodide 6LiI cylindrical scintillator crystal 4mm x 4mm size LUDLUM Model 42 coupled to a photomultiplier tube. Thermal tables are required to include polyethylene cross section in the simulation. These data are essential to get correct and accurate results in problems involving neutron thermalization. Nowadays available literature present the response matrix calculated with ENDF.B.V cross section libraries (V.Mares et al 1993) or with ENDF.B.VI (R.Vega Carrillo et al 2007). This work uses two novelties to calculate the response matrix. On the one hand the use of unstructured meshes to simulate the geometry of the detector and the Bonner Spheres and on the other hand the use of the updated ENDF.B.VII cross sections libraries. A set of simulations have been performed to obtain the detector response matrix. 29 mono energetic neutron beams between 10 KeV to 20 MeV were used as source for each moderator sphere up to a total of 174 simulations. Each mono energetic source was defined with the same diameter as the moderating sphere used in its corresponding simulation and the spheres were uniformly irradiated from the top of the photomultiplier tube. Some

  14. Evaluation of room-scattered neutrons at the JNC Tokai neutron reference field

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tadayoshi; Tsujimura, Norio [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works; Oyanagi, Katsumi [Japan Radiation Engineering Co., Ltd., Hitachi, Ibaraki (Japan)

    2002-09-01

    Neutron reference fields for calibrating neutron-measuring devices in JNC Tokai Works are produced by using radionuclide neutron sources, {sup 241}Am-Be and {sup 252}Cf sources. The reference field for calibration includes scattered neutrons from the material surrounding sources, wall, floor and ceiling of the irradiation room. It is, therefore, necessary to evaluate the scattered neutrons contribution and their energy spectra at reference points. Spectral measurements were performed with a set of Bonner multi-sphere spectrometers and the reference fields were characterized in terms of spectral composition and the fractions of room-scattered neutrons. In addition, two techniques stated in ISO 10647, the shadow-cone method and the polynomial fit method, for correcting the contributions from the room-scattered neutrons to the readings of neutron survey instruments were compared. It was found that the two methods gave an equivalent result within a deviation of 3.3% at a source-to-detector distance from 50cm to 500cm. (author)

  15. Evaluation of room-scattered neutrons at the JNC Tokai neutron reference field

    International Nuclear Information System (INIS)

    Yoshida, Tadayoshi; Tsujimura, Norio

    2002-01-01

    Neutron reference fields for calibrating neutron-measuring devices in JNC Tokai Works are produced by using radionuclide neutron sources, 241 Am-Be and 252 Cf sources. The reference field for calibration includes scattered neutrons from the material surrounding sources, wall, floor and ceiling of the irradiation room. It is, therefore, necessary to evaluate the scattered neutrons contribution and their energy spectra at reference points. Spectral measurements were performed with a set of Bonner multi-sphere spectrometers and the reference fields were characterized in terms of spectral composition and the fractions of room-scattered neutrons. In addition, two techniques stated in ISO 10647, the shadow-cone method and the polynomial fit method, for correcting the contributions from the room-scattered neutrons to the readings of neutron survey instruments were compared. It was found that the two methods gave an equivalent result within a deviation of 3.3% at a source-to-detector distance from 50cm to 500cm. (author)

  16. 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)

  17. 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)

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. {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.

  5. 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.

  6. 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

  7. 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.

  8. Correlation of Neutron Data Taken at Commercial Nuclear Sites

    Energy Technology Data Exchange (ETDEWEB)

    Rathbun, L. A.; Endres, G. W.R.

    1983-10-01

    In this report, data from neutron measurement and dosimetry studies performed by Pacific Northwest Laboratory, the Environmental Measurements Laboratory, and Rensselaer Polytechnic Institute are examined and compared. The purpose of this data correlation effort is to determine whether useful relationships exist between the actual neutron dose equivalent in a typical commercial nuclear power reactor and various measurement parameters, such as ratios of the response of 9-in. to 3-in. spheres, neutron/gamma ratios, albedo dosimeter response and neutron spectrometer readings. In most neutron radiation fields found in the reactors visited, the response of albedo dosimeters can be brought into reasonable agreement with dose equivalents measured with multispheres, tissue equivalent proportional counters (TEPCs) or remmeters. Because the responses of the remmeters, like the responses of albedo dosimeters, are energy dependent, it is preferable to correct the responses of the albedo dosimeters to agree with dose equivalents measured with either TEPCs or multispheres. If one of these laboratory systems has been used to measure neutron dose equivalents at a specific pressurized water reactor, a calculated average albedo dosimeter correction factor can be used for most locations at that reactor. However, if the measured 9-in. to 3-in. remmeter ratio is greater than 0.20, it is advisable to use a plot of 9-in. to 3-in. remmeter ratios versus albedo dosimeter correction factors to obtain an albedo dosimeter correction factor. Because 9-in. to 3-in. remmeter ratios at boiling water reactors are typically greater than 0.20, the latter approach applies to this type of reactor.

  9. 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.

  10. 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

  11. Study of the environmental neutron spectrum at Zacatecas city

    International Nuclear Information System (INIS)

    Vega C, H.R.

    2003-01-01

    The environmental neutron spectrum has been measured at Zacatecas City in Mexico. Neutron spectrum was unfolded from count rates obtained with a multisphere neutron spectrometer with a Li I(Eu) scintillator. With the spectrum information the ambient dose equivalent and the isotropic effective dose were calculated. A model based upon the geomagnetic latitude and the altitude above sea level, that allows to estimate the neutron fluence rate is proposed, the model results are compared with total neutron fluences measured at several locations worldwide. Environmental neutron spectrum shows peaks at 1 and 100 MeV as well as a relevant amount of low energy neutrons. The neutron fluence rate was 65 ± 3 cm -2 -h -1 , producing 13.7 ± 0.6 n Sv-h -1 due to ambient dose equivalent rate and an isotropic effective dose rate of 14.1 ± 0.6 n Sv-h -1 . Neutron fluence rates predicted with the model are in agreement with those reported in the literature. (Author)

  12. Study of the environmental neutron spectrum at Zacatecas city

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R. [Universidad Autonoma de Zacatecas, Cuerpo Academico de Radiobiologia, A.P. 336, 98000 Zacatecas (Mexico)

    2003-07-01

    The environmental neutron spectrum has been measured at Zacatecas City in Mexico. Neutron spectrum was unfolded from count rates obtained with a multisphere neutron spectrometer with a Li I(Eu) scintillator. With the spectrum information the ambient dose equivalent and the isotropic effective dose were calculated. A model based upon the geomagnetic latitude and the altitude above sea level, that allows to estimate the neutron fluence rate is proposed, the model results are compared with total neutron fluences measured at several locations worldwide. Environmental neutron spectrum shows peaks at 1 and 100 MeV as well as a relevant amount of low energy neutrons. The neutron fluence rate was 65 {+-} 3 cm{sup -2}-h{sup -1}, producing 13.7 {+-} 0.6 n Sv-h{sup -1} due to ambient dose equivalent rate and an isotropic effective dose rate of 14.1 {+-} 0.6 n Sv-h{sup -1}. Neutron fluence rates predicted with the model are in agreement with those reported in the literature. (Author)

  13. 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

  14. 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

  15. 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

  16. 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.

  17. Site-specific calibration of the Hanford personnel neutron dosimeter

    International Nuclear Information System (INIS)

    Endres, A.W.; Brackenbush, L.W.; Baumgartner, W.V.; Rathbone, B.A.

    1994-10-01

    A new personnel dosimetry system, employing a standard Hanford thermoluminescent dosimeter (TLD) and a combination dosimeter with both CR-39 nuclear track and TLD-albedo elements, is being implemented at Hanford. Measurements were made in workplace environments in order to verify the accuracy of the system and establish site-specific factors to account for the differences in dosimeter response between the workplace and calibration laboratory. Neutron measurements were performed using sources at Hanford's Plutonium Finishing Plant under high-scatter conditions to calibrate the new neutron dosimeter design to site-specific neutron spectra. The dosimeter was also calibrated using bare and moderated 252 Cf sources under low-scatter conditions available in the Hanford Calibration Laboratory. Dose equivalent rates in the workplace were calculated from spectrometer measurements using tissue equivalent proportional counter (TEPC) and multisphere spectrometers. The accuracy of the spectrometers was verified by measurements on neutron sources with calibrations directly traceable to the National Institute of Standards and Technology (NIST)

  18. 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)

  19. 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.

  20. 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)

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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%.

  9. 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%.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  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. Altitude variation of cosmic-ray neutrons

    International Nuclear Information System (INIS)

    Nakamura, T.; Uwamino, Y.; Ohkubo, T.; Hara, A.

    1987-01-01

    The altitude variation of the cosmic-ray neutron energy spectrum and the dose equivalent rate was measured at an average geomagnetic latitude of 24 degrees N by using the high-efficiency multi-sphere neutron spectrometer and neutron dose-equivalent counter developed by the authors. The data were obtained from a 2-h flight over Japan on 27 February 1985. The neutron energy spectra measured at sea level and at altitudes of 4880 m and at 11,280 m were compared with the calculated spectra of O'Brien and with other experimental spectra, and they are in moderately good agreement with them. The dose equivalent rate increases according to a quadratic curve up to about 6000 m and then increases linearly between 6000 m and 11,280 m. The dependence of dose equivalent rates at sea level and at an altitude of 12,500 m on geomagnetic latitude also is given by referring to other experimental results

  3. Study on neutron dosimetry in JNC Tokai Works

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, Norio [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works

    2003-03-01

    The author developed the neutron reference calibration fields using a {sup 252}Cf standard source surrounded with PMMA (polymethylmethacrylates) moderators at the Japan Nuclear Cycle Development Institute (JNC), Tokai Works. The moderators are concentric, annular cylinders made of lead-contained PMMA with a thickness of 13.5, 35.0, 59.5 and 77.0mm, and the {sup 252}Cf source is guided to the geometric center of moderators by the pneumatic system. These fields can provide the moderated neutron spectra very similar to those encountered around the globe-boxes of the fabrication process of MOX (PuO{sub 2}-UO{sub 2} mixed oxide) fuel. The neutron energy spectrum at the reference calibration point was evaluated from the calculations by MCNP4B and the measurements by the INS-type Bonner multi-sphere spectrometer and the hydrogen-filled proportional counters. The calculated neutron spectra were in good agreements with the measured ones. These fields were characterized in terms of the neutron fluence rate, spectral composition and ambient dose equivalent rate, and have served for the response-characterization of various neutron survey instruments. (author)

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.)

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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%.

  18. Neutron Dose Measurement Using a Cubic Moderator

    International Nuclear Information System (INIS)

    Sheinfeld, M.; Mazor, T.; Cohen, Y.; Kadmon, Y.; Orion, I.

    2014-01-01

    The Bonner Sphere Spectrometer (BSS), introduced In July 1960 by a research group from Rice University, Texas, is a major approach to neutron spectrum estimation. The BSS, also known as multi-sphere spectrometer, consists of a set of a different diameters polyethylene spheres, carrying a small LiI(Eu) scintillator in their center. What makes this spectrometry method such widely used, is its almost isotropic response, covering an extraordinary wide range of energies, from thermal up to even hundreds of MeVs. One of the most interesting and useful consequences of the above study is the 12'' sphere characteristics, as it turned out that the response curve of its energy dependence, have a similar shape compared with the neutron's dose equivalent as a function of energy. This inexplicable and happy circumstance makes it virtually the only monitoring device capable providing realistic neutron dose estimates over such a wide energy range. However, since the detection mechanism is not strictly related to radiation dose, one can expect substantial errors when applied to widely different source conditions. Although the original design of the BSS included a small 4mmx4mmO 6LiI(Eu) scintillator, other thermal neutron detectors has been used over the years: track detectors, activation foils, BF3 filled proportional counters, etc. In this study we chose a Boron loaded scintillator, EJ-254, as the thermal neutron detector. The neutron capture reaction on the boron has a Q value of 2.78 MeV of which 2.34 MeV is shared by the alpha and lithium particles. The high manufacturing costs, the encasement issue, the installation efficiency and the fabrication complexity, led us to the idea of replacing the sphere with a cubic moderator. This article describes the considerations, as well as the Monte-Carlo simulations done in order to examine the applicability of this idea

  19. Use of the helium-3 proportional counter for neutron spectrometry

    International Nuclear Information System (INIS)

    Vialettes, H.; Le Thanh, P.

    1967-01-01

    Up to now, two methods have been mainly used for neutron spectrometry near nuclear installations: - photographic emulsion spectrometry - the so-called, 'multisphere' technique spectrometry. The first method, which is fairly difficult to apply, has a threshold energy of about 500 keV; this is a big disadvantage for an apparatus which has to be used for spectrometry around nuclear installations where the neutron radiation is very much degraded energetically. The second method does not suffer from this disadvantage but the results which it yields are only approximate. In order to extend the energy range of the neutron spectra studied with sufficient accuracy the use of a helium-3 proportional counter has been considered. This report presents the principles of operation of the helium-3 spectrometer, and the calculation methods which make it possible to take into account the two main effects tending to deform the spectra obtained: - energy absorption by the walls of the counter, - energy loss of the incident neutrons due to elastic collisions with helium-3 nuclei. As an example of the application, the shape of the neutron spectrum emitted by a polonium-lithium source is given; the results obtained are in excellent agreement with theoretical predictions. (authors) [fr

  20. 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

  1. 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

  2. Simulation and optimization of a new focusing polarizing bender for the diffuse neutrons scattering spectrometer DNS at MLZ

    International Nuclear Information System (INIS)

    Nemkovski, K; Ioffe, A; Su, Y; Babcock, E; Schweika, W; Brückel, Th

    2017-01-01

    We present the concept and the results of the simulations of a new polarizer for the diffuse neutron scattering spectrometer DNS at MLZ. The concept of the polarizer is based on the idea of a bender made from the stack of the silicon wafers with a double-side supermirror polarizing coating and absorbing spacers in between. Owing to its compact design, such a system provides more free space for the arrangement of other instrument components. To reduce activation of the polarizer in the high intensity neutron beam of the DNS spectrometer we plan to use the Fe/Si supermirrors instead of currently used FeCoV/Ti:N ones. Using the VITESS simulation package we have performed simulations for horizontally focusing polarizing benders with different geometries in the combination with the double-focusing crystal monochromator of DNS. Neutron transmission and polarization efficiency as well as the effects of the focusing for convergent conventional C-benders and S-benders have been analyzed both for wedge-like and plane-parallel convergent geometries of the channels. The results of these simulations and the advantages/disadvantages of the various configurations are discussed. (paper)

  3. Simulation and optimization of a new focusing polarizing bender for the diffuse neutrons scattering spectrometer DNS at MLZ

    Science.gov (United States)

    Nemkovski, K.; Ioffe, A.; Su, Y.; Babcock, E.; Schweika, W.; Brückel, Th

    2017-06-01

    We present the concept and the results of the simulations of a new polarizer for the diffuse neutron scattering spectrometer DNS at MLZ. The concept of the polarizer is based on the idea of a bender made from the stack of the silicon wafers with a double-side supermirror polarizing coating and absorbing spacers in between. Owing to its compact design, such a system provides more free space for the arrangement of other instrument components. To reduce activation of the polarizer in the high intensity neutron beam of the DNS spectrometer we plan to use the Fe/Si supermirrors instead of currently used FeCoV/Ti:N ones. Using the VITESS simulation package we have performed simulations for horizontally focusing polarizing benders with different geometries in the combination with the double-focusing crystal monochromator of DNS. Neutron transmission and polarization efficiency as well as the effects of the focusing for convergent conventional C-benders and S-benders have been analyzed both for wedge-like and plane-parallel convergent geometries of the channels. The results of these simulations and the advantages/disadvantages of the various configurations are discussed.

  4. The energy spectrum of cosmic-ray induced neutrons measured on an airplane over a wide range of altitude and latitude

    International Nuclear Information System (INIS)

    Goldhagen, P.; Clem, J. M.; Wilson, J. W.

    2004-01-01

    Crews of high-altitude aircraft are exposed to radiation from galactic cosmic rays (GCRs). To help determine such exposures, the Atmospheric Ionizing Radiation Project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on a NASA ER-2 high-altitude airplane. The primary instrument was a sensitive extended-energy multisphere neutron spectrometer. Its detector responses were calculated for energies up to 100 GeV using the radiation transport code MCNPX 2.5.d with improved nuclear models and including the effects of the airplane structure. New calculations of GCR-induced particle spectra in the atmosphere were used to correct for spectrometer counts produced by protons, pions and light nuclear ions. Neutron spectra were unfolded from the corrected measured count rates using the deconvolution code MAXED 3.1. The results for the measured cosmic-ray neutron spectrum (thermal to >10 GeV), total neutron fluence rate, and neutron dose equivalent and effective dose rates, and their dependence on altitude and geomagnetic cut-off agree well with results from recent calculations of GCR-induced neutron spectra. (authors)

  5. Testing a newly developed single-sphere neutron spectrometer in reference monochromatic fields from 147 keV to 14.8 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Gómez-Ros, J.M. [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Pola, A.; Introini, M.V. [Politecnico di Milano - Dipartimento di Energia, Via Ponzio 34/3, 20133 Milano (Italy); Bortot, D. [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Politecnico di Milano - Dipartimento di Energia, Via Ponzio 34/3, 20133 Milano (Italy); Gentile, A.; Esposito, A.; Mazzitelli, G.; Buonomo, B.; Quintieri, L.; Foggetta, L. [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy)

    2013-06-21

    A new neutron spectrometer, designed to simultaneously respond from the thermal domain up to hundreds of MeV neutrons, was designed and built in the framework of the INFN project NESCOFI@BTF. It has been called SP{sup 2} (SPherical SPectrometer) and it consists of 31 thermal neutron detectors embedded in a 25 cm diameter polyethylene sphere with an internal 1 cm thick lead shell. The new spectrometer shows similar performance as the Bonner sphere spectrometer, but has the notable advantage of requiring only one exposure to determine the whole spectrum. The SP{sup 2} response matrix, previously calculated with MCNP, has been experimentally evaluated with monochromatic reference neutron fields from 147 keV to 14.8 MeV at PTB Braunschweig. As suitable thermal neutron detectors, Dysprosium activation foils were adopted at this stage. The results of the experiment confirmed the correctness of the response matrix within an overall uncertainty of ±3%. The next phase of the NESCOFI@BTF project will be the replacement of passive detectors with active counters, thus leading to a real-time spectrometric monitor that is expected to significantly innovate the neutron control task in neutron-producing facilities, such as the beam-lines for industrial irradiation or condensed matter studies.

  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. 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.

  8. Neutron-activation determination of phosphorus and sulfur in molybdenum and tungsten with the help of a beta-spectrometer

    International Nuclear Information System (INIS)

    Usmanova, M.M.; Mukhamedshina, N.M.; Kim, R.D.; Kaganov, L.K.

    1987-01-01

    An instrumental variant of the neutron-activation determination of phosphorus and sulfur in molybdenum and tungsten was developed with the help of a β-spectrometer that makes it possible to discriminate the participation of the 99 Mo and 187 W radioisotopes in the overall activity of the sample. It was shown that simultaneous determination of P and S on the basis of the 32 P radioisotope is feasible if their contents are comparable or are not different by more than 1-1.5 orders of magnitude, and then the maximum relative standard deviation is 0.15

  9. Novel type of neutron polarization analysis using the multianalyzer-equipment of the three-axes spectrometer PUMA

    Science.gov (United States)

    Schwesig, Steffen; Maity, Avishek; Sobolev, Oleg; Ziegler, Fabian; Eckold, Götz

    2018-01-01

    The combination of polarization analysis and multianalyzer system available at the three axes spectrometer PUMA@FRM II allows the simultaneous determination of both spin states of the scattered neutrons and the absolute value of the polarization. The present paper describes the technical details along with the basic formalism used for the precise calibration. Moreover, the performance of this method is illustrated by several test experiments including first polarized inelastic studies of the magnetic excitations of CuO in the multiferroic and the uniaxial antiferromagnetic phases.

  10. Measurement of the electron antineutrino angular correlation coefficient a with the neutron decay spectrometer aSPECT

    International Nuclear Information System (INIS)

    Simson, Martin

    2010-01-01

    This thesis describes measurements with the retardation spectrometer aSPECT at the Institut Laue-Langevin in Grenoble. The goal of the measurement is to determine the angular correlation coefficient a from the form of the proton recoil spectrum in the decay of the free neutron in order to determine a precise value for the ratio of the weak axial vector and vector coupling constants of the nucleon. A big improvement was achieved with the use of a silicon drift detector which was used here for the first time to detect low energetic protons. A saturation effect of the electronics that was only discovered during the analysis of the data from neutron decay proved to be not correctable. The findings from analysis, simulations and test experiments gained in this work should allow a measurement of a with high precision in a future beamtime. (orig.)

  11. Measurement of the electron antineutrino angular correlation coefficient a with the neutron decay spectrometer aSPECT

    Energy Technology Data Exchange (ETDEWEB)

    Simson, Martin

    2010-09-21

    This thesis describes measurements with the retardation spectrometer aSPECT at the Institut Laue-Langevin in Grenoble. The goal of the measurement is to determine the angular correlation coefficient a from the form of the proton recoil spectrum in the decay of the free neutron in order to determine a precise value for the ratio of the weak axial vector and vector coupling constants of the nucleon. A big improvement was achieved with the use of a silicon drift detector which was used here for the first time to detect low energetic protons. A saturation effect of the electronics that was only discovered during the analysis of the data from neutron decay proved to be not correctable. The findings from analysis, simulations and test experiments gained in this work should allow a measurement of a with high precision in a future beamtime. (orig.)

  12. Direct observation of effective temperature of Ta atom in layer compound TaS2 by neutron resonance absorption spectrometer

    International Nuclear Information System (INIS)

    Tokuda, Koji; Kamiyama, Takashi; Kiyanagi, Yoshiaki; Moreh, R.; Ikeda, Susumu

    2001-01-01

    A neutron resonance absorption spectrometer, DOG has been installed at KENS, High Energy Accelerator Research Organization Neutron Source, which enables us to investigate the motions of a particular element by analyzing the line width of resonance absorption spectrum. We measured the temperature dependence of the effective temperature of Ta motion in TaS 2 as well as in Ta metal using DOG. The effective temperatures extracted from the observed absorption spectrum agree well with the calculated values from the phonon density of states of Ta metal over a wide temperature range of 10 to 300 K. We also succeeded in measuring both the angular dependence and the temperature dependence of effective temperatures of Ta in a layer compound TaS 2 . Based on the temperature dependence of the effective temperature, the partial phonon density of states of Ta in TaS 2 was discussed. (author)

  13. Measurement of the electron-antineutrino angular correlation coefficient a in neutron beta decay with the spectrometer aSPECT

    International Nuclear Information System (INIS)

    Petzoldt, G.

    2007-01-01

    In the four beam times we performed at the FRM-II, we were able to show that the spectrometer works in principle and that a determination of a with it is possible. A set of routines has been written for decoding and analyzing the raw data. The routines are written in C using the ROOT libraries and can be easily adapted or expanded. We have found a reliable way to extract the proton count rates from the data by building pulseheight spectra for each measurement, subtracting background measurements from those and fitting the resulting peak with a Gaussian. The background of the measurements was studied in detail. The background caused by electrons from neutron decay is very well understood and conforms quantitatively to our expectation. Due to the spatial resolution of our detector and the time resolution provided by our DAQ electronics, we were able to study correlated electron-proton pairs from one neutron decay event. They form a clearly visible peak in a time- and channel-distance spectrum, which can be shifted in the channel-dimension by varying the voltages applied to the lower and upper E x B electrodes. Performing a pulseheight analysis for both involved particles allowed us to obtain a fairly clean energy spectrum of the background caused by electrons from neutron decay in our detector. Using these correlations for data analysis may be of interest for future neutron decay experiments which use segmented detectors. (orig.)

  14. Measurement of the electron-antineutrino angular correlation coefficient a in neutron beta decay with the spectrometer aSPECT

    Energy Technology Data Exchange (ETDEWEB)

    Petzoldt, G.

    2007-08-29

    In the four beam times we performed at the FRM-II, we were able to show that the spectrometer works in principle and that a determination of a with it is possible. A set of routines has been written for decoding and analyzing the raw data. The routines are written in C using the ROOT libraries and can be easily adapted or expanded. We have found a reliable way to extract the proton count rates from the data by building pulseheight spectra for each measurement, subtracting background measurements from those and fitting the resulting peak with a Gaussian. The background of the measurements was studied in detail. The background caused by electrons from neutron decay is very well understood and conforms quantitatively to our expectation. Due to the spatial resolution of our detector and the time resolution provided by our DAQ electronics, we were able to study correlated electron-proton pairs from one neutron decay event. They form a clearly visible peak in a time- and channel-distance spectrum, which can be shifted in the channel-dimension by varying the voltages applied to the lower and upper E x B electrodes. Performing a pulseheight analysis for both involved particles allowed us to obtain a fairly clean energy spectrum of the background caused by electrons from neutron decay in our detector. Using these correlations for data analysis may be of interest for future neutron decay experiments which use segmented detectors. (orig.)

  15. HYSPEC: A crystal time-of-flight hybrid spectrometer for the spallation neutron source with polarization capabilities

    International Nuclear Information System (INIS)

    Shapiro, S.M.; Zaliznyak, I.A.; Passell, L.; Ghosh, V.J.; Leonhardt, W.J.; Hagen, M.E.

    2006-01-01

    The hybrid spectrometer (HYSPEC) is a unique direct geometry inelastic scattering instrument under construction at the spallation neutron source (SNS). It combines the intensity enhancement features of focusing Bragg crystals with time-of-flight energy analysis. It will be located at beam-line 14B, which views a coupled liquid hydrogen moderator. A neutron beam from the moderator will travel along a curved guide, through a Fermi chopper and will then be focused onto a sample in an external building, 39 m from the source. In this configuration the intensity at the sample position is more than an order of magnitude larger than for other planned inelastic instrument. A movable detector bank 4.5 m from the sample will cover an angular range of 60 deg. in the horizontal plane and 15 deg. in the vertical direction. An important feature of HYSPEC is the ability to do neutron polarization analysis experiments. A Heusler crystal, which polarizes the neutron beam, can be used as the focusing crystal and a series of bender analyzers will analyze the polarization of the scattered beam

  16. Design and development of wide energy neutron REM equivalent spectrometer-dosimeters based on polycarbonates and Cr-39

    International Nuclear Information System (INIS)

    Faermann, S.

    1985-03-01

    This work describes a system composed of a Rem response personnel neutron dosemeter, based on boron radiators and a polycarbonate track detector, for monitoring dose equivalents in the energy range 1 eV to 14 MeV, an electrochemical etching system for revealing damage sites in solid state track etch detectors, a reader for magnifying the etched pits and a microprocessor for evaluating the dose equivalents and their uncertainties. The performance and directional dependence of the dosemeter when exposed to monoenergetic and polyenergetic neutron fields in the epithermal and fast energy regions are discussed. Saturation effects in polycarbonate foils are presented and a comparison is made between the response of polycarbonate and CR-39 foils, used as passive detectors in the dosemeter. A new passive miniature fast neutron spectrometer-dosimeter is also described. The device is based on the detection of proton tracks by electrochemical etching of CR-39 foils covered with thin polyethylene layers of different thicknesses. By means of this device it is possible to assess the fast neutron energy spectrum in 10 energy intervals in the energy range 0.5-15 MeV. Dose equivalents can be determined in the dose equivalent range 20 mRem to 8 Rem, approximately (author)

  17. Use of the helium-3 proportional counter for neutron spectrometry; Utilisation du compteur proportionnel a helium 3 pour la spectrometrie des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Vialettes, H; Le Thanh, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    Up to now, two methods have been mainly used for neutron spectrometry near nuclear installations: - photographic emulsion spectrometry - the so-called, 'multisphere' technique spectrometry. The first method, which is fairly difficult to apply, has a threshold energy of about 500 keV; this is a big disadvantage for an apparatus which has to be used for spectrometry around nuclear installations where the neutron radiation is very much degraded energetically. The second method does not suffer from this disadvantage but the results which it yields are only approximate. In order to extend the energy range of the neutron spectra studied with sufficient accuracy the use of a helium-3 proportional counter has been considered. This report presents the principles of operation of the helium-3 spectrometer, and the calculation methods which make it possible to take into account the two main effects tending to deform the spectra obtained: - energy absorption by the walls of the counter, - energy loss of the incident neutrons due to elastic collisions with helium-3 nuclei. As an example of the application, the shape of the neutron spectrum emitted by a polonium-lithium source is given; the results obtained are in excellent agreement with theoretical predictions. (authors) [French] Jusqu'ici deux methodes ont ete utilisees principalement pour la spectrometrie des neutrons autour des installations nucleaires: - la spectrometrie par emulsions photographiques - la spectrometrie par la technique dite des multispheres. La premiere methode, d'un emploi assez delicat presente un seuil en energie d'environ 500 keV qui est un obstacle serieux a la spectrometrie autour des installations nucleaires ou le rayonnement neutronique est tres degrade en energie. La deuxieme methode ne presente pas cet inconvenient mais les resultats qu'elle permet d'obtenir ne sont qu'approches. Pour etendre la gamme d'energie des spectres de neutrons etudies avec une precision suffisante, l'utilisation du

  18. A method for the determination of detector channel dead time for a neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Adib, M.; Salama, M.; Abd-Kawi, A.; Sadek, S.; Hamouda, I.

    1975-01-01

    A new method is developed to measure the dead time of a detector channel for a neutron time-of-flight spectrometer. The method is based on the simultaneous use of two identical BF 3 detectors but with two different efficiencies, due to their different enrichment in B 10 . The measurements were performed using the T.O.F. spectrometer installed at channel No. 6 of the ET-RR-1 reactor. The main contribution to the dead time was found to be due to the time analyser and the neutron detector used. The analyser dead time has been determined using a square wave pulse generator with frequency of 1 MC/S. For channel widths of 24.4 us, 48.8 ud and 97.6 us, the weighted dead times for statistical pulse distribution were found to be 3.25 us, 1.87 us respectively. The dead time of the detector contributes mostly to the counting losses and its value was found to be (33+-3) us

  19. First test of SP{sup 2}: A novel active neutron spectrometer condensing the functionality of Bonner spheres in a single moderator

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R. [INFN-LNF Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Bortot, D. [Politecnico di Milano—Dipartimento di Energia, Via Ponzio 34/3, 20133 Milano (Italy); INFN—sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Buonomo, B.; Esposito, A. [INFN-LNF Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Gómez-Ros, J.M. [INFN-LNF Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Introini, M.V.; Lorenzoli, M.; Pola, A. [Politecnico di Milano—Dipartimento di Energia, Via Ponzio 34/3, 20133 Milano (Italy); INFN—sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Sacco, D. [INFN-LNF Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); INAIL—DPIA Via di Fontana Candida n.1, 00040 Monteporzio C. (Italy)

    2014-12-11

    The NESCOFI@BTF (2011–2013) international collaboration was established to develop realtime neutron spectrometers to simultaneously cover all energy components of neutron fields, from thermal up to hundreds MeV. This communication concerns a new spherical spectrometer, called SP^2, which condenses the functionality of an Extended Range Bonner Sphere Spectrometer (ERBSS) into a single moderator embedding multiple active thermal neutron detectors. The possibility of achieving the complete spectrometric information in a single exposure constitutes a great advantage compared to the ERBSS. The first experimental test of the instrument, performed with a reference 241Am–Be source in different irradiation geometries, is described. The agreement between observed and simulated response is satisfactory for all tested geometries.

  20. The upgraded cold neutron three-axis spectrometer FLEXX at BER II at HZB

    DEFF Research Database (Denmark)

    Duc Le, Manh; Skoulatos, Markos; Quintero-Castro, Diana Lucía

    2014-01-01

    Larmor labeling is seen as one of the key ingredients in the development of novel neutron instrumentation. FLEXX puts special emphasis on exploiting the neutron resonance spin echo (NRSE) technique for high-resolution spectroscopy on dispersive quasi-particle excitations. This enables unique...

  1. Development of the neutron reference calibration field using a {sup 252}Cf standard source surrounded with PMMA moderators

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, T.; Kanai, K.; Tsujimura, N. [Japan Nuclear Cycle Development Institute, Ibaraki-ken (Japan)

    2002-07-01

    The authors developed the neutron reference calibration fields using a {sup 252} Cf standard source surrounded with PMMA moderators at the Japan Nuclear Cycle Development (JNC), Tokai Works. The moderators are co-axial, hollow cylinders made of lead-contained PMMA with a thickness of 13.5, 35.0, 59.5 and 77.0mm, and the {sup 252} Cf source is guided to the geometric center of moderators by the pneumatic system. These fields can provide the moderated neutron spectra very similar to those encountered around the globe-boxes of the fabrication process of MOX (PuO{sub 2}-UO{sub 2} mixed oxide) fuel. The neutron energy spectrum at the reference calibration point was evaluated from the calculations by MCNP4B and the measurements by the INS-type Bonner multi-sphere spectrometer and the hydrogen-filled proportional counters. The calculated neutron spectra were in good agreements with the measured ones. These fields were characterized in terms of the neutron fluence rate, spectral composition and ambient dose equivalent rate, and have served for the response-characterization of various neutron survey instruments.

  2. Development of the neutron reference calibration field using a 252Cf standard source surrounded with PMMA moderators

    International Nuclear Information System (INIS)

    Yoshida, T.; Kanai, K.; Tsujimura, N.

    2002-01-01

    The authors developed the neutron reference calibration fields using a 252 Cf standard source surrounded with PMMA moderators at the Japan Nuclear Cycle Development (JNC), Tokai Works. The moderators are co-axial, hollow cylinders made of lead-contained PMMA with a thickness of 13.5, 35.0, 59.5 and 77.0mm, and the 252 Cf source is guided to the geometric center of moderators by the pneumatic system. These fields can provide the moderated neutron spectra very similar to those encountered around the globe-boxes of the fabrication process of MOX (PuO 2 -UO 2 mixed oxide) fuel. The neutron energy spectrum at the reference calibration point was evaluated from the calculations by MCNP4B and the measurements by the INS-type Bonner multi-sphere spectrometer and the hydrogen-filled proportional counters. The calculated neutron spectra were in good agreements with the measured ones. These fields were characterized in terms of the neutron fluence rate, spectral composition and ambient dose equivalent rate, and have served for the response-characterization of various neutron survey instruments

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  4. Application of a Bonner sphere spectrometer for determination of the energy spectra of neutrons generated by ≈1 MJ plasma focus

    Czech Academy of Sciences Publication Activity Database

    Králík, M.; Krása, Josef; Velyhan, Andriy; Scholz, M.; Ivanova-Stanik, I.M.; Bienkowska, B.; Miklaszewski, R.; Schmidt, H.; Řezáč, K.; Klír, D.; Kravárik, J.; Kubeš, P.

    2010-01-01

    Roč. 81, č. 11 (2010), 113503/1-113503/5 ISSN 0034-6748 R&D Projects: GA MŠk LA08024 Grant - others:FP-6 EU(XE) RITA-CT2006-26095 Institutional research plan: CEZ:AV0Z10100523 Keywords : plasma focus * fusion DD neutrons * Bonner sphere spectrometer * energy spectra of scattered neutrons * unfolded and calculated spectra Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.598, year: 2010

  5. The vTAS suite: A simulator for classical and multiplexed three-axis neutron spectrometers

    International Nuclear Information System (INIS)

    Boehm, M.; Filhol, A.; Raoul, Y.; Kulda, J.; Schmidt, W.; Schmalzl, K.; Farhi, E.

    2013-01-01

    The vTAS suite provides graphical assistance to prepare and perform inelastic neutron scattering experiments on a TAS instrument, including latest multiplexed instrumental configurations, such as FlatCone, IMPS and UFO. The interactive display allows for flexible translation between instrument positions in real space and neutron scattering conditions represented in reciprocal space. It is a platform independent public domain software tool, available for download from the website of the Institut Laue Langevin (ILL).

  6. Direct mass measurements of neutron-deficient xenon isotopes with the ISOLTRAP mass spectrometer

    International Nuclear Information System (INIS)

    Dilling, J.; Audi, G.; Beck, D.; Bollen, G.; Henry, S.; Herfurth, F.; Kellerbauer, A.; Kluge, H.-J.; Lunney, D.; Moore, R.B.; Scheidenberger, C.; Schwarz, S.; Sikler, G.; Szerypo, J.

    2002-01-01

    The masses of Xe isotopes with 124≥A≥114 have been measured using the ISOLTRAP spectrometer at the on-line mass separator ISOLDE/CERN. A mass resolving power of 500 000 was chosen resulting in an accuracy of δm∼12 keV for all isotopes investigated. Conflicts with existing mass data of several standard deviations were found

  7. Development of Data Acquisition and Measurement Software for Neutron Triple Axis Spectrometer at BATAN-Serpong, Indonesia

    Directory of Open Access Journals (Sweden)

    B Bharoto

    2017-06-01

    Full Text Available The Neutron Scattering Laboratory at the National Nuclear Energy Agency of Indonesia (BATAN possesses several neutron beam instruments for materials science research. One of the instruments is a neutron triple-axis spectrometer (TAS. Due to the malfunction of the main computer, the original main control system had to be replaced with a new one. For this reason, a new data acquisition and measurement software program based on GNU C++ programming language was developed for restoring the spectrometer's functionality. However, using the resulting control system, triple-axis mode experiments were very difficult to perform and their types that can be performed were limited. In order to conduct the experiments more effectively and efficiently, several improvements in both hardware and software have been developed. The Visual Basic programming language was used in developing the data acquisition and measurement software that makes it possible for all motors to move simultaneously, so that the time spent for the experiments is reduced significantly. Also, programmable motor controller cards were used for driving all the 23 motors of the instrument. All the 23 axes can be controlled by clicking the appropriate buttons or inputting text command in the main window of the software's user interface. The software has also been used to perform an elastic experiment, as well as an inelastic experiment for investigating the phenomenon of phonon. The software developed is more user friendly than the older ones, since the spectrometer status and the experiment results can be displayed in real time at the windows, and it also makes experiments more effective and efficient since the experiments can be automated and run without any user intervention until the experiments finish. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso

  8. Measurement of the proton recoil spectrum in neutron beta decay with the spectrometer aSPECT. Study of systematic effects

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Gertrud Emilie

    2012-01-24

    Free neutron decay, n{yields}pe anti {nu}{sub e}, is the simplest nuclear beta decay, well described as a purely left-handed, vector minus axial-vector interaction within the framework of the Standard Model (SM) of elementary particles and fields. Due to its highly precise theoretical description, neutron beta decay data can be used to test certain extensions to the SM. Possible extensions require, e.g., new symmetry concepts like left-right symmetry, new particles, leptoquarks, supersymmetry, or the like. Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the SM in high-energy physics. In this doctoral thesis, a measurement of the proton recoil spectrum with the neutron decay spectrometer aSPECT is described. From the proton spectrum the antineutrinoelectron angular correlation coefficient a can be derived. In our first beam time at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany (2005-2006), background instabilities due to particle trapping and the electronic noise level of the proton detector prevented us from presenting a new value for a. In the latest beam time at the Institut Laue-Langevin (ILL) in Grenoble, France (2007-2008), the trapped particle background has been reduced sufficiently and the electronic noise problem has essentially been solved. For the first time, a silicon drift detector was used. As a result of the data analysis, we identified and fixed a problem in the detector electronics which caused a significant systematic error. The target figure of the latest beam time was a new value for a with a total relative error well below the present literature value of 4 %. A statistical accuracy of about 1.4% was reached, but we could only set upper limits on the correction of the problem in the detector electronics, which are too high to determine a meaningful result. The present

  9. Measurement of the proton recoil spectrum in neutron beta decay with the spectrometer aSPECT. Study of systematic effects

    International Nuclear Information System (INIS)

    Konrad, Gertrud Emilie

    2012-01-01

    Free neutron decay, n→pe anti ν e , is the simplest nuclear beta decay, well described as a purely left-handed, vector minus axial-vector interaction within the framework of the Standard Model (SM) of elementary particles and fields. Due to its highly precise theoretical description, neutron beta decay data can be used to test certain extensions to the SM. Possible extensions require, e.g., new symmetry concepts like left-right symmetry, new particles, leptoquarks, supersymmetry, or the like. Precision measurements of observables in neutron beta decay address important open questions of particle physics and cosmology, and are generally complementary to direct searches for new physics beyond the SM in high-energy physics. In this doctoral thesis, a measurement of the proton recoil spectrum with the neutron decay spectrometer aSPECT is described. From the proton spectrum the antineutrinoelectron angular correlation coefficient a can be derived. In our first beam time at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz in Munich, Germany (2005-2006), background instabilities due to particle trapping and the electronic noise level of the proton detector prevented us from presenting a new value for a. In the latest beam time at the Institut Laue-Langevin (ILL) in Grenoble, France (2007-2008), the trapped particle background has been reduced sufficiently and the electronic noise problem has essentially been solved. For the first time, a silicon drift detector was used. As a result of the data analysis, we identified and fixed a problem in the detector electronics which caused a significant systematic error. The target figure of the latest beam time was a new value for a with a total relative error well below the present literature value of 4 %. A statistical accuracy of about 1.4% was reached, but we could only set upper limits on the correction of the problem in the detector electronics, which are too high to determine a meaningful result. The present doctoral

  10. 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

  11. Direct mass measurements of neutron-deficient xenon isotopes using the ISOLTRAP mass spectrometer

    CERN Document Server

    Dilling, J; Beck, D; Bollen, G; Herfurth, F; Kellerbauer, A G; Kluge, H J; Moore, R B; Scheidenberger, C; Schwarz, S; Sikler, G

    2004-01-01

    The masses of the noble-gas Xe isotopes with 114 $\\leq$ A $\\leq$ 123 have been directly measured for the first time. The experiments were carried out with the ISOLTRAP triple trap spectrometer at the online mass separator ISOLDE/CERN. A mass resolving power of the Penning trap spectrometer of $m/\\Delta m$ of close to a million was chosen resulting in an accuracy of $\\delta m \\leq 13$ keV for all investigated isotopes. Conflicts with existing, indirectly obtained, mass data by several standard deviations were found and are discussed. An atomic mass evaluation has been performed and the results are compared to information from laser spectroscopy experiments and to recent calculations employing an interacting boson model.

  12. Mass spectrometer provided with an optical system for separating neutron particles against charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Reeher, J R; Story, M S; Smith, R D

    1977-03-03

    This invention concerns a mass spectrometer with an ion focusing optical system that efficiently separates the charged and neutral particles. It concerns an apparatus that can be used in ionisation areas operating at relatively high pressure (> 10/sup -2/ Torr). The invention relates more particularly to a mass spectrometer with an inlet device for the samples to be identified, a sample ionisation system for forming charged and neutral particles, a mass analyser and an optical system for focusing the ions formed in the mass analyser. The optics include several conducting components of which at least one has sides formed of grids, in the direction of the axis, towards the analyser the optics forming a potential well along the axis. The selected charged particles are focused in the analyser and the remaining particles can escape by the openings in the conducting grids.

  13. Beta strength distributions in neutron-deficient Kr and Sr isotopes using a total absorption spectrometer

    CERN Document Server

    Maréchal, F

    2003-01-01

    Far from the line of stability, beta -decay studies are often a primary source of information on nuclear structure. The measured beta -strength distribution for a given decay can be used to verify the accuracy of our theoretical description of the parent nucleus ground state and the states populated in the daughter nucleus. Total absorption spectrometers based on large NaI crystals are well suited tools to determine the beta -strength distribution over the whole Q /sub EC/ decay window. The newly built spectrometer TAgS, dedicated to such studies, is presented and its performances and possibilities are discussed in the light of experiments performed at the ISOLDE /CERN mass separator. The resulting information on ground state deformations for the /sup 74/Kr and /sup 76/Sr isotopes are discussed. (22 refs).

  14. Measuring and acquisition unit of the polarized neutron spectrometer SPN-1; Izmeritel`no0nakopitel`nyj modul` spektrometra na polyarizovannykh nejtronakh SPI-1

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravlev, V V; Korneev, D A; Litvinenko, E I; Lyapin, D I

    1996-12-31

    SPN-1 polarized neutron time-of-flight spectrometer operates on IBR-2 reactor in JINR LNF. It is used to investigate into micromagnetism in ferromagnetics and superconductors as well as to investigate into mono and multilayer magnetic and superconducting thin films. 14 refs.; 3 figs.

  15. Design and validation of a single sphere multi-detector neutron spectrometer based on LiF: Mg,Cu,P thermoluminescent dosemeters

    International Nuclear Information System (INIS)

    Gomez-Ros, Jose Maria; Bedogni, Roberto; Moraleda, Montserrat; Romero, Ana; Delgado, Antonio; Esposito, Adolfo

    2010-01-01

    This communication describes a new neutron spectrometer consisting of pairs of 7 Li and 6 Li based thermoluminescent dosemeters (MCP-6, MCP-7) 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 in order to obtain a nearly isotropic response for neutrons in the energy range up to 20 MeV. A partial validation of the calculated response matrix has been performed with the calibrated 241 Am-Be neutron source at the INFN-LNF Laboratory, using the shadow cone technique.

  16. Deep inelastic neutron scattering on {sup 207}Pb and NaHF{sub 2} as a test of a detectors array on the VESUVIO spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Pietropaolo, A. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica and Centro NAST - Nanoscienze and Nanotecnologie and Strumentazione, via della Ricerca Scientifica 1, 00133 Rome (Italy)], E-mail: antonino.pietropaolo@roma2.infn.it; Senesi, R. [Universita degli Studi di Roma Tor Vergata, Dipartimento di Fisica and Centro NAST - Nanoscienze and Nanotecnologie and Strumentazione, via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2008-01-11

    A prototype array of resonance detectors for deep inelastic neutron scattering experiments has been installed on the VESUVIO spectrometer, at the ISIS spallation neutron source. Deep inelastic neutron scattering measurements on a reference lead sample and on NaHF{sub 2} molecular system are presented. Despite on an explorative level, the results obtained for the values of mean kinetic energy are found in good agreement with the theoretical predictions, thus assessing the potential capability of the device for a routine use on the instrument.

  17. Deep inelastic neutron scattering on 207Pb and NaHF 2 as a test of a detectors array on the VESUVIO spectrometer

    Science.gov (United States)

    Pietropaolo, A.; Senesi, R.

    2008-01-01

    A prototype array of resonance detectors for deep inelastic neutron scattering experiments has been installed on the VESUVIO spectrometer, at the ISIS spallation neutron source. Deep inelastic neutron scattering measurements on a reference lead sample and on NaHF 2 molecular system are presented. Despite on an explorative level, the results obtained for the values of mean kinetic energy are found in good agreement with the theoretical predictions, thus assessing the potential capability of the device for a routine use on the instrument.

  18. Deep inelastic neutron scattering on 207Pb and NaHF2 as a test of a detectors array on the VESUVIO spectrometer

    International Nuclear Information System (INIS)

    Pietropaolo, A.; Senesi, R.

    2008-01-01

    A prototype array of resonance detectors for deep inelastic neutron scattering experiments has been installed on the VESUVIO spectrometer, at the ISIS spallation neutron source. Deep inelastic neutron scattering measurements on a reference lead sample and on NaHF 2 molecular system are presented. Despite on an explorative level, the results obtained for the values of mean kinetic energy k > are found in good agreement with the theoretical predictions, thus assessing the potential capability of the device for a routine use on the instrument

  19. Time lens for high-resolution neutron time-of-flight spectrometers

    International Nuclear Information System (INIS)

    Baumann, K.; Gaehler, R.; Grigoriev, P.; Kats, E.I.

    2005-01-01

    We examine in analytic and numeric ways the imaging effects of temporal neutron lenses created by traveling magnetic fields. For fields of parabolic shape we derive the imaging equations, investigate the time magnification, the evolution of the phase-space element, the gain factor, and the effect of finite beam size. The main aberration effects are calculated numerically. The system is technologically feasible and should convert neutron time-of-flight instruments from pinhole to imaging configuration in time, thus enhancing intensity and/or time resolution. Further fields of application for high-resolution spectrometry may be opened

  20. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Middendorf, H.D. [Univ. of Oxford (United Kingdom); Miller, A. [Stirling Univ., Stirling (United Kingdom)

    1994-12-31

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers.

  1. The performance of neutron spectrometers AR a long-pulse spallation source

    International Nuclear Information System (INIS)

    Pynn, R.; Daemen, L.L.

    1995-01-01

    At a recent workshop at Lawrence Berkeley National Laboratory members of the international neutron scattering community discussed the performance to be anticipated from neutron scattering instruments installed at a 1 MW long-pulse spallation source (LPSS). Although the report of this workshop is long, its principal conclusions can be easily summarised and almost as easily understood. This article presents such a synthesis for a 60 Hz LPSS with 1 msec proton pulses. We discuss some of the limitations of the workshop conclusions and suggest a simple analysis of the performance differences that might be expected between short- and long-pulse sources both of which exploit coupled moderators

  2. Neutron scattering studies of the dynamics of biopolymer-water systems using pulsed-source spectrometers

    International Nuclear Information System (INIS)

    Middendorf, H.D.; Miller, A.

    1994-01-01

    Energy-resolving neutron scattering techniques provide spatiotemporal data suitable for testing and refining analytical models or computer simulations of a variety of dynamical processes in biomolecular systems. This paper reviews experimental work on hydrated biopolymers at ISIS, the UK Pulsed Neutron Facility. Following an outline of basic concepts and a summary of the new instrumental capabilities, the progress made is illustrated by results from recent experiments in two areas: quasi- elastic scattering from highly hydrated polysaccharide gels (agarose and hyaluronate), and inelastic scattering from vibrational modes of slightly hydrated collagen fibers

  3. Sensitivity of peak positions to flight-path parameters in a deep-inelastic scattering neutron TOF spectrometer

    International Nuclear Information System (INIS)

    Gray, E.MacA.; Chatzidimitriou-Dreismann, C.A.; Blach, T.P.

    2012-01-01

    The effects of small changes in flight-path parameters (primary and secondary flight paths, detector angles), and of displacement of the sample along the beam axis away from its ideal position, are examined for an inelastic time-of-flight (TOF) neutron spectrometer, emphasising the deep-inelastic regime. The aim was to develop a rational basis for deciding what measured shifts in the positions of spectral peaks could be regarded as reliable in the light of the uncertainties in the calibrated flight-path parameters. Uncertainty in the length of the primary or secondary flight path has the least effect on the positions of the peaks of H, D and He, which are dominated by the accuracy of the calibration of the detector angles. This aspect of the calibration of a TOF spectrometer therefore demands close attention to achieve reliable outcomes where the position of the peaks is of significant scientific interest and is discussed in detail. The corresponding sensitivities of the position of peak of the Compton profile, J(y), to flight-path parameters and sample position are also examined, focusing on the comparability across experiments of results for H, D and He. We show that positioning the sample to within a few mm of the ideal position is required to ensure good comparability between experiments if data from detectors at high forward angles are to be reliably interpreted.

  4. Mechanical neutron spectrometer Chopper - Experimental study of the neutron beam topography in the channel C of the 'A' reactor; Neutronski mehanicki spektrometar (coper) - Eksperimentalno odredjivanje topografije neutronskog snopa na kanalu 'C', reaktora 'A'

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-12-15

    The objective of the experiment was to measure the axis of the neutron beam from the reactor channel. The collimator, mechanical spectrometer and detectors are to be placed along this axis. Two points along the channel are determined to be defined as centres of the neutron beam. During this experiments the collimators were placed in the reactor at distance of 100 cm and cross section of 3.5 cm in diameter. BF{sub 3} detectors were used for the experiment.

  5. Neutron spectrometry with Bonner spheres for area monitoring in particle accelerators

    International Nuclear Information System (INIS)

    Bedogni, R.

    2011-01-01

    Selecting the instruments to determine the operational quantities in the neutron fields produced by particle accelerators involves a combination of aspects, which is peculiar to these environments: the energy distribution of the neutron field, the continuous or pulsed time structure of the beam, the presence of other radiations to which the neutron instruments could have significant response and the large variability in the dose rate, which can be observed when moving from areas near the beam line to free-access areas. The use of spectrometric techniques in support of traditional instruments is highly recommended to improve the accuracy of dosimetric evaluations. The multi-sphere or Bonner Sphere Spectrometer (BSS) is certainly the most used device, due to characteristics such as the wide energy range, large variety of active and passive detectors suited for different workplaces, good photon discrimination and the simple signal management. Disadvantages are the poor energy resolution, weight and need to sequentially irradiate the spheres, leading to usually long measurement sessions. Moreover, complex unfolding analyses are needed to obtain the neutron spectra. This work is an overview of the BSS for area monitoring in particle accelerators. (authors)

  6. 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.

  7. Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute

    Energy Technology Data Exchange (ETDEWEB)

    Afach, S.; Fertl, M.; Franke, B., E-mail: beatrice.franke@psi.ch, E-mail: bernhard.lauss@psi.ch; Kirch, K. [Paul Scherrer Institute, Villigen (Switzerland); Institute for Particle Physics, Eidgenössische Technische Hochschule, Zürich (Switzerland); Bison, G.; Burri, F.; Chowdhuri, Z.; Daum, M.; Henneck, R.; Lauss, B., E-mail: beatrice.franke@psi.ch, E-mail: bernhard.lauss@psi.ch; Meier, M.; Schmidt-Wellenburg, P.; Zsigmond, G. [Paul Scherrer Institute, Villigen (Switzerland); Bodek, K.; Zejma, J. [Jagellonian University, Cracow (Poland); Grujic, Z.; Kasprzak, M.; Weis, A. [University of Fribourg (Switzerland); Hélaine, V. [Laboratoire de Physique Corpusculaire, Caen (France); Paul Scherrer Institute, Villigen (Switzerland); Koch, H.-C. [Institut für Physik, Johannes-Gutenberg-Universität, Mainz (Germany); University of Fribourg (Switzerland); and others

    2014-08-28

    The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5 m × 2.5 m × 3 m, disturbances of the magnetic field are attenuated by factors of 5–50 at a bandwidth from 10{sup −3} Hz up to 0.5 Hz, which corresponds to integration times longer than several hundreds of seconds and represent the important timescale for the neutron electric dipole moment measurement. These shielding factors apply to random environmental noise from arbitrary sources. This is achieved via a proportional-integral feedback stabilization system that includes a regularized pseudoinverse matrix of proportionality factors which correlates magnetic field changes at all sensor positions to current changes in the SFC coils.

  8. A passive Bonner sphere spectrometer for in-flight neutron spectrometry

    International Nuclear Information System (INIS)

    Hajek, M.; Berger, T.; Vana, N.

    2003-01-01

    The neutron energy spectrum was measured onboard a series of four return flights between Cologne (Germany) and Washington, DC (USA) during the solar minimum conditions of June/July 1996. This experiment was world-wide the first determination of the neutron spectrum by passive spectrometry methods onboard an aircraft. The project was conducted with the support of the German Airforce which reserved two seat rows in the front of an Airbus A 310-304 for the passive BSS. The count rates were computed according to the Pair Method and unfolded with MAXED. Obtained spectrum shows two relative maxima around 1 and 100 MeV, the second of which cannot be completely assessed by the applied BSS. The agreement between measurement and calculation proved to be excellent

  9. Measuring module of spectrometer of neutron small angle scattering on the IBR pulse reactor

    International Nuclear Information System (INIS)

    Vagov, V.A.; Zhukov, G.P.; Kozlova, E.P.; Korobchenko, M.L.; Namsraj, Yu.; Ostanevich, Yu.M.; Savvateev, A.S.; Salamatin, I.M.; Sirotin, A.P.

    1980-01-01

    Equipment and software for experiments with neutron small angle scattering is described. It is intended for data acquisition, equipment control storage of collected data and their output to network of the Laboratory measuring centre. The set-up equipment includes: 9 neutron detectors with corresponding electronic apparatus, sample exchanging device, communication link, SM-3 type minicomputer of an extended configuration and some units of CAMAC electronic equipment. The software (MUR applied operatio system) is intended for the automatic performance of the given number of cycles of successive uniform runs of a given duration with the sample list at two possible filter positions. Besides, the MUR system contains test, debugging and service software. The software has been designed using the SANPO system means [ru

  10. 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

  11. An improved slow neutron spectrometer at nuclear research reactor et-r r-1. Vol. 2

    Energy Technology Data Exchange (ETDEWEB)

    Abu El-Ela, M A [Reactor and Neutron Physics, Nuclear Research Center, AEA, Cairo (Egypt)

    1996-03-01

    An improved slow neutron selector has been aligned at channel number 6 of the nuclear research reactor ET-R R-1 Inshas. The flight path is 4 meter. The collimator-rotor-collimator system has the dimensions 0.3 x 2.5 x 70 cm with the rotor diameter 16 cm and 3 slits of 0.3 x 2.5 cm cross section. The rotor rotation rate varies between 600 r.p.m. the counting system has one of the best modern high electronic advanced technology time analyzer with minimum dwell time 2 sec, 8192 channels and a double detector inputs of TTL and NEG NIM standard pulses. The analyzer external triggering signals are of TTL standard type. A special design {sup 3} He detector for time of flight spectrometry has been used in the SNS. The reactor bare thermal neutron spectrum has been successfully measured, to show good agreement with the previous data. 6 figs.

  12. Enhancing the performances of a resonance detector spectrometer for deep inelastic neutron scattering measurements

    International Nuclear Information System (INIS)

    Filabozzi, A.; Pace, E.; Pietropaolo, A.

    2012-01-01

    The possibility is explored to sum up neutron Compton profiles at different scattering angles in deep inelastic neutron scattering measurements within the Resonance Detector (RD) configuration to enhance the statistics for a more reliable extraction of the momentum distribution of the constituents in the target. The RD configuration allows to select the energy of the scattered neutrons up to several tens of electron Volt, thus accessing energy and wave vector transfers well above 1 eV and 30 Å −1 , respectively. In the high-q/ω regime, the final state effects could be considered as negligible, as shown in a series of simulations using a Monte Carlo method with different inverse geometry instrument setups. The simulations show that it could be possible to conceive an instrument set up where the RD configuration allows the proper summation of several spectra at different scattering angles, providing a good separation of the proton recoil signal from that of the heavier atoms, thus avoiding the cell subtraction by fitting procedure.

  13. Performance of the second Deep Inelastic Neutron Scatering spectrometer at the Bariloche electron LINAC

    International Nuclear Information System (INIS)

    Palomino, L A Rodríguez; Blostein, J J; Dawidowski, J

    2013-01-01

    We report on the new Deep Inelastic Neutron Scattering detector bank recently implemented at the Bariloche electron LINAC. We show the characterization and calibration process carried out, which comprises the determinarion of the detector bank efficiency, and the evaluation of the performance of the filter difference technique. As part of the benchmarking process, polyethylene spectra were measured and analyzed, and the scattering cross sections for carbon and hydrogen were determined in the process. With the addition of this new detector bank to the existing one, we evaluate the combined capacity of the two banks

  14. Evaluating the BD-100R [Bubble Technology Industries] as a neutron spectrometer through pressure variation

    International Nuclear Information System (INIS)

    White, B.; Ebert, D.; Munno, F.

    1990-01-01

    Other investigators have evaluated the dose response of neutron bubble dosimeters for possible use as personnel monitors for the U.S. Navy in low level radiation fields. In addition to dose measurements, these devices have been modified to measure the neutron energy spectra. These methods tend to be cumbersome, inaccurate, or both and do not use the same devices as employed in the dosimetry. The BD-100R dosimeter used in this work consists of a test tube containing an elastic polymer with interspersed droplets of two types of Freon; Freon-12 and Freon-114. Each superheated liquid droplet is a potential nucleation site. The minimum energy needed to form a bubble from the nucleation site is given by, E = 16πγ 3 (T)/3(ΔP) 2 , where ΔP is the difference between the vapor pressure of the droplet and the applied pressure. Upon reaching a critical radius, a bubble becomes unstable and grows in size. It may be seen from this equation that the energy deposition required for bubble formation is inversely proportional to the square of the pressure difference. The number of bubbles formed continually decreases with increasing applied pressure, until a pressure is reached where no bubbles are formed since the energy transferred can no longer vaporize the Freon. This investigation is intended to demonstrate the determination of an unknown spectrum utilizing the dosimeter response (number of bubbles formed) as a function of the neutron energy (applied pressure). A set of 12 dosimeters was initially exposed outside the East Beam Port (EBP) at the Maryland University Training Reactor (MUTR). The dosimeters were inside a pressure chamber which could accommodate up to 18 dosimeters. The same set of dosimeters were irradiated using a paraffin moderated PuBe source for which the neutron energy spectrum is unknown. There were eight exposures of six dosimeters at varied pressures in the EBP. The average number of bubbles and standard deviation was measured for each pressure. Data

  15. Neutron spectrum measurement inside containment vessel at Kori nuclear power plant unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Han, J. M.; Kim, T. W.; Kim, K. D.; Youn, C. H. [Nuclear Environment Technology Institute, Taejon (Korea, Republic of)

    2003-10-01

    There would be a case for the radiation worker have to work inside of the containment vessel to inspect or repair reactor facilities. In this case, the information about distribution of neutron field is needed to estimate neutron exposure dose of worker. Neutron spectra were measured by BMS(Bonner Multisphere Spectrometer) at 4 points of 6 ft and 20 ft, 2 points of 44 ft, 5 points of 70 ft in containment vessel of Kori unit 1. From the calculation, the following results were obtained. Neutron fluxes of 6 ft were between 2.623 x 10{sup 2} and 2.746 x 10{sup 4} neutron/cm{sup 2}{center_dot}sec, average neutron energies were between 9.209 x 10{sup -6} and 3.377 x 10{sup -2} MeV, equivalent doses of neutron were between 0.025 and 2.675 mSv/hr. Neutron fluxes of 20 ft were between 1.771 x 10{sup 1} and 1.682 x 10{sup 3} neutron/cm{sup 2}{center_dot}sec, average neutron energies were between 6.084 x 10{sup -6} and 2.988 x 10{sup -1} MeV, equivalent doses of neutron were between 0.004 and 0.228 mSv/hr. Neutron fluxes of 44 ft were between 3.367 x 10{sup 2} and 3.483 x 10{sup 2} neutron / cm{sup 2}{center_dot}sec, average neutron energies were between 3.962 x 10{sup -2} and 7.360 x 10{sup -2} MeV, equivalent doses of neutron were between 0.069 and 0.089 mSv/hr. Neutron fluxes of 70 ft were between 4.553 x 10{sup 3} and 1.407 x 10{sup 4} neutron/cm{sup 2}{center_dot}sec, average neutron energies were between 3.668 x 10{sup -4} and 6.764 x 10{sup -2} MeV, equivalent doses of neutron were between 0.449 and 2.660 mSv/hr.

  16. Measurements of fuel and ablator ρR in Symmetry-Capsule implosions with 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.; Séguin, F. H.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bionta, R. M.; Casey, D. T.; Caggiano, J. A.; Hatarik, R.; Khater, H. Y.; Sayre, D. B. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Knauer, J. P.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Herrmann, H. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Kilkenny, J. D. [General Atomics, San Diego, California 92186 (United States)

    2014-11-15

    The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility (NIF) measures the neutron spectrum in the energy range of 4–20 MeV. This paper describes MRS measurements of DT-fuel and CH-ablator ρR in DT gas-filled symmetry-capsule implosions at the NIF. DT-fuel ρR's of 80–140 mg/cm{sup 2} and CH-ablator ρR's of 400–680 mg/cm{sup 2} are inferred from MRS data. The measurements were facilitated by an improved correction of neutron-induced background in the low-energy part of the MRS spectrum. This work demonstrates the accurate utilization of the complete MRS-measured neutron spectrum for diagnosing NIF DT implosions.

  17. Simulations and measurements of the performance of a channeled neutron guide for a time-of-flight spectrometer at the NIST Center for Neutron Research

    International Nuclear Information System (INIS)

    Cook, Jeremy C.; Copley, John R.D.

    2004-01-01

    We describe the identification and analysis of the principal sources of intensity loss within the five-channeled neutron guide tube that was originally installed in the chopper section of the Disk Chopper Spectrometer at the National Institute of Standards and Technology Center for Neutron Research. (The purpose of the five channels was to optimize intensity and resolution in three different modes of operation known as ''resolution modes.'') By combining measurements, Monte Carlo simulations, and analytical calculations, we have developed a model that successfully explains performance losses in the original guide. We have used this model to quantify expected returns in performance using a replacement guide in which the principal contributions to the intensity loss are reduced to the minimum achievable with current technology. We have also estimated the intensity gains that would be achieved if one of the limited number of options were adopted for modifying the original guide in a manner likely to produce such gains. We describe factors that affect the performance of the original guide and compare the measured and predicted performance of the modified guide against predictions for the optimal replacement guide. The simulations indicate that the modified guide (which has three channels rather than the original five) produces greater intensity gains over a large incident wavelength band for the low and medium resolution modes, whereas a high quality replacement guide greatly improves performance in the high resolution mode of operation. Because the low and medium resolution modes are most heavily demanded, we opted to modify the guide rather than replace it. We describe the nature of this modification and present intensity measurements that meet or exceed predictions in all resolution modes with no detectable change in the energy resolution nor increase in the instrumental background

  18. The orphee versatile low-cost multiprocessor system for data acquisition and control of neutron spectrometers

    International Nuclear Information System (INIS)

    Koskas, G.

    1988-01-01

    This paper describes the new data acquisition and control system of the neutron scattering instruments at the ORPHEE research reactor. The existing system has undergone a complete change: the original CAMAC system and minicomputer controlling each experiment have given way to commercial CPU boards and microcomputers like the IBM-PC. The communication links between these two components are the IEEE 488 or RS232 standards. Emphasis is placed on the flexibility and modular nature of such a system which makes a maximum use of commercial products thus guaranteeing reliability and ease of use. A study of the requirements and evolutions, technical as well as philosophical, is detailed to demonstrate the motivation of the choice of the system architecture. A survey of the various hardware and software achievements and finally an overview of future improvements is given

  19. Time-of-flight spectrometer for slow neutrons in use at the reactor in Saclay. Its application for the study of the inelastic diffusion of cold neutrons; L'appareillage de spectrometrie a temps-de-vol pour neutrons lents en service a la pile de Saclay. Son application a l'etude de la diffusion inelastique des neutrons froids

    Energy Technology Data Exchange (ETDEWEB)

    Jacsot, B; Netter, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Galula, M [Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France)

    1955-07-01

    The time-of-flight spectrometers is constituted of a mechanic swivel obturator which absorbs neutrons until energies above 1 KeV, a mechanic filter which allow to retain only high wave length components and a delayed pulses selector with 100 channels. Its main application field is the thermic region where it allowed to measure the inelastic scattering of neutrons using various materials as H{sub 2}O, D{sub 2}O, Be, BeO, etc... (M.P.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-21

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

  1. The Text of the Agreement for conducting under the Auspices of the Agency. A Regional Joint Training and Research Programme using a Neutron Crystal Spectrometer

    International Nuclear Information System (INIS)

    1964-01-01

    On 11 June 1964 the Board of Governors approved an Agreement for conducting, under the auspices of the Agency, a regional joint training and research programme using a neutron crystal spectrometer. The text of that Agreement is reproduced in this document for the information of all Members. The entry into force of the Agreement in accordance with Section 17 thereof, as well as later acceptances by additional Governments, will be notified to Members in addenda to this document

  2. The Text of the Agreement for conducting under the Auspices of the Agency. A Regional Joint Training and Research Programme using a Neutron Crystal Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1964-07-22

    On 11 June 1964 the Board of Governors approved an Agreement for conducting, under the auspices of the Agency, a regional joint training and research programme using a neutron crystal spectrometer. The text of that Agreement is reproduced in this document for the information of all Members. The entry into force of the Agreement in accordance with Section 17 thereof, as well as later acceptances by additional Governments, will be notified to Members in addenda to this document.

  3. Determination of the neutron and photon dose equivalent at work places in nuclear facilities of Sweden. An SSI - EURADOS comparison exercise. Part 2: Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, D. [National Radiological Protection Board, Chilton (United Kingdom); Drake, P. [Vattenfall AB, Vaeroebacka (Sweden); Lindborg, L. [Swedish Radiation Protection Inst., Stockholm (Sweden); Klein, H. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Schmitz, Th. [Forschungszentrum Juelich GmbH, Juelich (Germany); Tichy, M

    1999-06-01

    Various mixed neutron-photon fields at workplaces in the containment of pressurised water reactors and in the vicinity of transport containers with spent fuel elements were investigated with spectrometers and dosimeters. The spectral neutron fluences evaluated from measurements with multisphere systems were recommended to be used for the calculation of dosimetric reference values for comparison with the readings of the dosemeters applied simultaneously. It turned out that most of the moderator based area dosemeters overestimated, while the TEPC systems generally underestimated the ambient dose equivalent (DE) values of the rather soft neutron fields encountered at these workplaces. The discrepancies can, however, be explained on the basis of energy dependent responses of the instruments used. The ambient DE values obtained with recently developed area dosemeters based on superheated drop detectors and with track etch based personal dosemeters on phantoms, however, were in satisfying agreement with the reference data. Sets of personal dosemeters simultaneously irradiated on a phantom allowed to roughly estimate the directional dependence of the neutron fluence. Hence, personal and limiting dose equivalent quantities could also be calculated. The personal and ambient DE values were always conservative estimates of the limiting quantities. Unexpectedly, discrepancies were observed for photon DE data measured with GM counters and TEPC systems. The up to 50 % higher readings of the GM counters may be explained by a considerable contribution of high energy photons to the total photon dose equivalent, but photon spectrometry is necessary for final clarification.

  4. Determination of the neutron and photon dose equivalent at work places in nuclear facilities of Sweden. An SSI - EURADOS comparison exercise. Part 2: Evaluation

    International Nuclear Information System (INIS)

    Bartlett, D.; Drake, P.; Lindborg, L.; Klein, H.; Schmitz, Th.; Tichy, M.

    1999-06-01

    Various mixed neutron-photon fields at workplaces in the containment of pressurised water reactors and in the vicinity of transport containers with spent fuel elements were investigated with spectrometers and dosimeters. The spectral neutron fluences evaluated from measurements with multisphere systems were recommended to be used for the calculation of dosimetric reference values for comparison with the readings of the dosemeters applied simultaneously. It turned out that most of the moderator based area dosemeters overestimated, while the TEPC systems generally underestimated the ambient dose equivalent (DE) values of the rather soft neutron fields encountered at these workplaces. The discrepancies can, however, be explained on the basis of energy dependent responses of the instruments used. The ambient DE values obtained with recently developed area dosemeters based on superheated drop detectors and with track etch based personal dosemeters on phantoms, however, were in satisfying agreement with the reference data. Sets of personal dosemeters simultaneously irradiated on a phantom allowed to roughly estimate the directional dependence of the neutron fluence. Hence, personal and limiting dose equivalent quantities could also be calculated. The personal and ambient DE values were always conservative estimates of the limiting quantities. Unexpectedly, discrepancies were observed for photon DE data measured with GM counters and TEPC systems. The up to 50 % higher readings of the GM counters may be explained by a considerable contribution of high energy photons to the total photon dose equivalent, but photon spectrometry is necessary for final clarification

  5. Experimental assessment of the performance of a proposed lead slowing-down spectrometer at WNR/PSR [Weapons Neutron Research/Proton Storage Ring

    International Nuclear Information System (INIS)

    Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A.; Danon, Y.; Block, R.C.; Slovacek, R.E.; Hoff, R.W.; Lougheed, R.W.

    1990-01-01

    In November 1989, we carried out a measurement of the fission cross section of 247 Cm, 250 Cf, and 254 Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 μg for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs

  6. Experimental assessment of the performance of a proposed lead slowing-down spectrometer at WNR/PSR (Weapons Neutron Research/Proton Storage Ring)

    Energy Technology Data Exchange (ETDEWEB)

    Moore, M.S.; Koehler, P.E.; Michaudon, A.; Schelberg, A. (Los Alamos National Lab., NM (USA)); Danon, Y.; Block, R.C.; Slovacek, R.E. (Rensselaer Polytechnic Inst., Troy, NY (USA)); Hoff, R.W.; Lougheed, R.W. (Lawrence Livermore National Lab., CA (USA))

    1990-01-01

    In November 1989, we carried out a measurement of the fission cross section of {sup 247}Cm, {sup 250}Cf, and {sup 254}Es on the Rensselaer Intense Neutron Source (RINS) at Rensselaer Polytechnic Institute (RPI). In July 1990, we carried out a second measurement, using the same fission chamber and electronics, in beam geometry at the Los Alamos Neutron Scattering Center (LANSCE) facility. Using the relative count rates observed in the two experiments, and the flux-enhancement factors determined by the RPI group for a lead slowing-down spectrometer compared to beam geometry, we can assess the performance of a spectrometer similar to RINS, driven by the Proton Storage Ring (PSR) at the Los Alamos National Laboratory. With such a spectrometer, we find that is is feasible to make measurements with samples of 1 ng for fission 1 {mu}g for capture, and of isotopes with half-lives of tens of minutes. It is important to note that, while a significant amount of information can be obtained from the low resolution RINS measurement, a definitive determination of average properties, including the level density, requires that the resonance structure be resolved. 12 refs., 5 figs., 3 tabs.

  7. Experimental test of a newly developed single-moderator, multi-detector, directional neutron spectrometer in reference monochromatic fields from 144 keV to 16.5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Gómez-Ros, J.M. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Pola, A.; Bortot, D. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria 16, 20133 Milano (Italy); Gentile, A. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Introini, M.V. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria 16, 20133 Milano (Italy); Buonomo, B. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Lorenzoli, M. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria 16, 20133 Milano (Italy); Mazzitelli, M. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Sacco, D. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); INAIL – DPIA, Via di Fontana Candida n.1, 00040 Monteporzio Catone (Italy)

    2015-05-11

    A new directional neutron spectrometer called CYSP (CYlindrical SPectrometer) was developed within the NESCOFI@BTF (2011–2013) collaboration. The device, composed by seven active thermal neutron detectors located along the axis of a cylindrical moderator, was designed to simultaneously respond from the thermal domain up to hundreds of MeV neutrons. The new spectrometer condenses the performance of the Bonner Sphere Spectrometer in a single moderator; thus requiring only one exposure to determine the whole spectrum. The CYSP response matrix, determined with MCNP, has been experimentally evaluated with monochromatic reference neutron fields from 144 keV to 16.5 MeV, plus a {sup 252}Cf source, available at NPL (Teddington, UK). The results of the experiment confirmed the correctness of the response matrix within an overall uncertainty of ±2.5%. The new active spectrometer CYSP offers an innovative option for real-time monitoring of directional neutron fields as those produced in neutron beam-lines.

  8. Study of neutron spectra using sources of {sup 241}AmBE and {sup 238}PuBe moderated in water; Estudo de espectros neutrônicos com fontes de {sup 241}AmBE e {sup 238}PuBe moderados em água

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Angela S.; Silva, Fellipe S.; Patrão, Karla C.S.; Fonseca, Evaldo S. da; Pereira, Walsan W., E-mail: angela.souzagon@gmail.com [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Metrologia de Neutrons; Fundação Técnico-Educacional Souza Marques (FTESM), Rio de Janeiro, RJ (Brazil)

    2017-11-01

    Recent works demonstrate the increasing importance of characterizing the spectrum of neutron sources for various energies. The main objective of this study is to make the understanding of the interaction of neutrons as close as possible to the reality in which the workers act, thus allowing to act directly in the area of radioprotection. In this way, neutron fluence determination of the {sup 241}AmBe source of 0.6 TBq (16 Ci) and {sup 238} PuBe 1.8 TBq (50 Ci) free in the air and inserted in aluminium spheres of 16 cm and 20.5 cm filled with distilled water. The measurements were carried out in the low scattering laboratory of the Laboratory of Neutron Metrology, in order to obtain a more realistic spectrum. Spectrum determination is based on measurement using the Bonner multisphere spectrometer containing readings with the ball-free detector and covered with polyethylene spheres having diameters of: 5,08 cm (2″), 7,62 cm (3″), 12,70 cm (5″), 20,32 cm (8″), 25,40 cm (10″) e 30,48 cm (12″). The aim is to characterize a new moderate spectrum in water using the sources of {sup 238}PuBe and {sup 241}AmBe that may represent realistic fields in the radioprotection area useful for testing, calibration and irradiation of individual and area monitors for neutrons.

  9. Neutron total cross-section of hydrogenous and deuterated 1- and 2-propanol and n-butanol measured using the VESUVIO spectrometer

    Science.gov (United States)

    Rodríguez Palomino, L. A.; Dawidowski, J.; Márquez Damián, J. I.; Cuello, G. J.; Romanelli, G.; Krzystyniak, M.

    2017-10-01

    This work presents the total cross sections of a set of normal and deuterated alcohols (hydrogenous 1- and 2-propanol and n-butanol, 1-propanol(OD) and fully deuterated 2-propanol and n-butanol), measured at spectrometer VESUVIO (ISIS spallation neutron source, United Kingdom). Granada's Synthetic Model was applied to describe those systems and a satisfactory agreement with the measured total cross section was achieved in the range of energies from 10-3 to 100 eV. The input parameters of the model were determined from the essential features of the vibrational spectra of the atoms that compose the systems, which were studied using Molecular Dynamics.

  10. 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)

  11. Testing measurements at horizontal channels of the MARIA reactor performed using neutron spectrometers; Pomiary testowe przy kanalach poziomych reaktora MARIA wykonane przy uzyciu spektrometrow neutronow

    Energy Technology Data Exchange (ETDEWEB)

    Murasik, A. [Institute of Atomic Energy, Otwock-Swierk (Poland)

    1997-12-31

    By means of neutron diffraction, using the standard polycrystalline sample of Al{sub 2}O{sub 3}, measurements on three (of four spectrometers) already installed in the front of horizontal channels of MARIA reactor have been performed. Basing on these experiments as well as on activation measurements carried out earlier, the fluxes of monoenergetic neutrons have been estimated. These experiments allowed to determine (for a given geometry and kind of monochromators chosen) the resolution efficiency of instruments and high order contamination in the reflected beam. With the help of polycrystalline vanadium and TbBr{sub 3} sample, the possibility of studies using the inelastic scattering process have been tested. (author) 7 refs, 15 figs, 7 tabs

  12. 2005 annual report of MEXT specially promoted research, 'Development of the 4D Space Access Neutron Spectrometer (4SEASONS) and elucidation of the Mechanism of Oxide High-Tc superconductivity'

    International Nuclear Information System (INIS)

    Arai, Masatoshi; Kajimoto, Ryoichi; Nakajima, Kenji; Shamoto, Shin'ichi; Soyama, Kazuhiko; Nakamura, Mitsutaka; Aizawa, Kazuya; Asaoka, Hidehito; Kodama, Katsuaki; Inamura, Yasuhiro; Imai, Yoshinori; Yokoo, Tetsuya; Ino, Takashi; Yamada, Kazuyoshi; Fujita, Masaki; Ohoyama, Kenji; Hiraka, Haruhiro

    2006-11-01

    A research project entitled 'Development of the 4D Space Access Neutron Spectrometer (4SEASONS) and Elucidation of the Mechanism of Oxide High-T c Superconductivity' has started in 2005 (repr. by M. Arai). It is supported by MEXT, Grant-in-Aid for Specially Promoted Research and is going to last until fiscal 2009. The goal of the project is to elucidate the mechanism of oxide high-T c superconductivity by neutron scattering technique. For this purpose, we will develop an inelastic neutron scattering instrument 4SEASONS (4d SpacE AccesS neutrON Spectrometer) for the spallation neutron source in Japan Proton Accelerator Research Complex (J-PARC). The instrument will have 100 times higher performance than existing world-class instruments, and will enable detailed observation of anomalous magnetic excitations and phonons in a four-dimensional momentum-energy space. This report summarizes the progress in the research project in fiscal 2005. (author)

  13. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    International Nuclear Information System (INIS)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-01-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E o and 90 o with respect to the beam-line. Here the ERBSS of UAB (Universidad Autonoma de Barcelona-Grup de Fisica de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were exposed to characterize the 'forward' and 'sideward' proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and calibrated, is important for guaranteeing the robustness of the measured spectra and estimating their overall uncertainties.

  14. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    International Nuclear Information System (INIS)

    Bedogni, R.; Amgarou, K.; Domingo, C.; Russo, S.; Cirrone, G.A.P.; Pelliccioni, M.; Esposito, A.; Pola, A.; Introini, M.V.; Gentile, A.

    2012-01-01

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. The ERBSSs of UAB (Universidad Autónoma de Barcelona-Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  15. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Amgarou, K.; Domingo, C. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Russo, S.; Cirrone, G.A.P. [Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali dei Sud, Via S. Sofia 62, 95125 Catania (Italy); Pelliccioni, M.; Esposito, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy); Pola, A.; Introini, M.V. [Politecnico di Milano, CESNEF, Dipartimento di Energia, via Ponzio 34/3, 20133 Milano (Italy); Gentile, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati (Italy)

    2012-07-21

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0 Degree-Sign and 90 Degree-Sign with respect to the beam-line. The ERBSSs of UAB (Universidad Autonoma de Barcelona-Grup de Fisica de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  16. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Science.gov (United States)

    Bedogni, R.; Amgarou, K.; Domingo, C.; Russo, S.; Cirrone, G. A. P.; Pelliccioni, M.; Esposito, A.; Pola, A.; Introini, M. V.; Gentile, A.

    2012-07-01

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. The ERBSSs of UAB (Universidad Autónoma de Barcelona-Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  17. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  18. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  19. Evaluation of neutron dosimetry techniques for well-logging operations

    International Nuclear Information System (INIS)

    Cummings, F.M.; Haggard, D.L.; Endres, G.W.R.

    1985-07-01

    Neutron dose and energy spectral measurements from 241 AmBe and a 14 MeV neutron generator were performed at a well-logging laboratory. The measurement technique included the tissue equivalent proportional counter, multisphere, two types of remmeters and five types of personnel neutron dosimeters. Several source configurations were used to attempt to relate data to field situations. The results of the measurements indicated that the thermoluminescent albedo dosimeter was the most appropriate personnel neutron dosimeter, and that the most appropriate calibration source would be the source normally employed in the field with the calibration source being used in the unmoderated configuration. 7 refs., 35 figs., 14 tabs

  20. Development and Analysis of Volume Multi-Sphere Method Model Generation using Electric Field Fitting

    Science.gov (United States)

    Ingram, G. J.

    Electrostatic modeling of spacecraft has wide-reaching applications such as detumbling space debris in the Geosynchronous Earth Orbit regime before docking, servicing and tugging space debris to graveyard orbits, and Lorentz augmented orbits. The viability of electrostatic actuation control applications relies on faster-than-realtime characterization of the electrostatic interaction. The Volume Multi-Sphere Method (VMSM) seeks the optimal placement and radii of a small number of equipotential spheres to accurately model the electrostatic force and torque on a conducting space object. Current VMSM models tuned using force and torque comparisons with commercially available finite element software are subject to the modeled probe size and numerical errors of the software. This work first investigates fitting of VMSM models to Surface-MSM (SMSM) generated electrical field data, removing modeling dependence on probe geometry while significantly increasing performance and speed. A proposed electric field matching cost function is compared to a force and torque cost function, the inclusion of a self-capacitance constraint is explored and 4 degree-of-freedom VMSM models generated using electric field matching are investigated. The resulting E-field based VMSM development framework is illustrated on a box-shaped hub with a single solar panel, and convergence properties of select models are qualitatively analyzed. Despite the complex non-symmetric spacecraft geometry, elegantly simple 2-sphere VMSM solutions provide force and torque fits within a few percent.

  1. Optimisation of a collimator array for a multi-detector time-of-flight spectrometer for fast neutrons

    International Nuclear Information System (INIS)

    Schlegel-Bickmann, D.

    1979-01-01

    A Monte Carlo program has been developed which calculates the neutron background due to the interaction between incident neutrons and the collimator fan near the detector in dependence of geometry and material parameters. The position of the neutron source with regard to the collimators may be chosen at random. The program is also suitable for other three-dimensional transport problems of fast neutrons in the energy range between 0.5 and 20 MeV. The modular structure makes it easy to adapt it to highly specific problems. (orig.) 891 HP 892 MB [de

  2. First records of thermal neutrons with the spectrometer for time of flight (TOF) in the RP-10 Nuclear Reactor

    International Nuclear Information System (INIS)

    Munive, M.; Baltuano, O; Soto, C; Ravello, Y

    2002-01-01

    To obtain the first spectrum of an emergent beam of neutrons of a nuclear reactor is the main parameter of the characterization in the use of this reactor; one of ways to get this spectrum is for the technique of time of flight, TOF, which registers the time that a neutron need to cover a certain distance, associating this time then to the kinetic energy of the neutron. The kinetic study of the beam of neutrons is carried out on neutron pulses that are generated by a revolving choke called Chopper; and the analysis in the time of the detected pulses is carried out for a system MCS. Using this technique it is achieved the record of the spectra in energy, or in wavelength , of the irradiation facilities No 2 and 4, and of the exit N o 5 of the thermal column of the Nuclear Reactor RP-10 of the Nuclear Center Oscar de la Guerra RACSO, Peru (au)

  3. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Science.gov (United States)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-10-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to ECATANA) of INFN—LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. Here the ERBSS of UAB (Universidad Autónoma de Barcelona— Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati) were exposed to characterize the "forward" and "sideward" proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and calibrated, is important for guaranteeing the robustness of the measured spectra and estimating their overall uncertainties.

  4. Measurement of the angular correlation coefficient a between electron and antineutrino in neutron β-decay with the spectrometer aSPECT

    International Nuclear Information System (INIS)

    Maisonobe, Romain

    2014-01-01

    Neutron β-decay is parametrized by several measurable correlation coefficients which are used to determine parameters of the Standard Model and to search for new physics. The aim of the retardation spectrometer aSPECT is to measure the electron-antineutrino angular correlation coefficient a with an unprecedented accuracy of well below 1%. The coefficient is extracted from a high precision measurement of the proton energy spectrum. A central point of this PhD thesis is the analysis of the background, motivated by the observations of discharges during the beam time of 2011, and an earlier indication for a dependence on the retardation potential. During this thesis, several measurements were conducted off-line, without ionizing particles from neutron decay. An 'internal' background (X-rays and ions) was identified. It has an influence of 10 -5 to 10 -4 on Δa/a depending on the vacuum level (∼10 -9 mbar) and the spectrometer settings. Within the analysis of the data from the beam time in 2013, a model was built to correct for backgrounds present in neutron decay experiment, taking into account its time dependence. The correction is about 3% on the coefficient for standard settings and vacuum but it can reach 7% for unfavorable settings. To reduce the background, a drift electric field was applied close to the maximum of the retardation potential. Additional measurements performed during this beam time included tests of systematics, in particular the edge effect (beam profile) and different electrode settings. In order to obtain the final result, the analysis has to be extended by including the different corrections and by comparing with simulations of the systematic effects. (author)

  5. Characterization of neutron spectra using sources of {sup 241}AmBe, {sup 238}PuBe e {sup 252}Cf moderated in water; Caracterização de espectros neutrônicos com fontes de {sup 241}AmBe, {sup 238}PuBe e {sup 252}Cf moderados em água

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, A.S.; Silva, F.S.; Patrão, K.C.S.; Fonseca, E.S. da; Pereira, W.W., E-mail: angela.souzagon@gmail.com [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratório de Metrologia de Nêutrons

    2017-07-01

    Recent studies have demonstrated the importance of characterizing the spectrum of neutron sources for various energies in order to make the understanding of neutron interaction closer to reality they work with. This work presents the determination of neutron energy flux from the source of {sup 241}AmBe (0.6 TBq), {sup 238}PuBe (1.8 TBq) and {sup 252}Cf (120 μg) free in the air and inserted into spheres of various diameters containing distilled water. The determination of the spectrum is based on the measurement and simulation by the Monte Carlo computational method, using the sources under study, with the Bonner multisphere spectrometer containing readings with the detector without sphere and covered with polyethylene balls of diameters: 5,08 cm (2 ″), 7.62 cm (3″), 12.70 cm (5 ″), 20.32 cm (8 ″), 25.40 cm (10 ″) and 30.48 cm (12 ″). It is sought to characterize a new moderate spectrum in water using the sources of {sup 241}AmBe, {sup 238}PuBe and {sup 252}Cf that may be useful for testing, calibration and irradiation of individual and area monitors for neutrons.

  6. Measuring the energies and multiplicities of prompt gamma-ray emissions from neutron-induced fission of $^{235}$U using the STEFF spectrometer

    CERN Document Server

    AUTHOR|(CDS)2093036; Smith, Alastair Gavin; Wright, Tobias James

    Following a NEA high priority nuclear data request, an experimental campaign to measure the prompt $\\gamma$-ray emissions from $^{235}$U has been performed. This has used the STEFF spectrometer at the new Experimental Area 2 (EAR2) within the neutron timeof-flight facility (n_TOF), a white neutron source facility at CERN with energies from thermal to approximately 1 GeV. Prior to the experimental campaign, STEFF has been optimised for the environment of EAR2. The experimental hall features a high background $\\gamma$-ray rate, due to the nature of the spallation neutron source. Thus an investigation into reduction of the background $\\gamma$-ray rate, encountered by the NaI(Tl) detector array of STEFF, has been carried out. This has been via simulations using the simulation package FLUKA. Various materials and shielding geometries have been investigated but the effects determined to be insufficient in reducing the background rate by a meaningful amount. The NaI(Tl) detectors have been modified to improve their ...

  7. A fast neutron spectrometer based on an electrochemically etched CR-39 detector with degrader and front radiator

    International Nuclear Information System (INIS)

    Matiullah; Durrani, S.A.

    1987-01-01

    In addition to having promising applications for the development of a fast-neutron dosemeter, electrochemically etched (ECE) CR-39 detectors also offer the possibility of energy-selective fast-neutron detection. This property stems basically from the fact that, to produce 'sparkable' trails in the polymeric detector subjected to ECE, the charged particle resulting from a neutron interaction must fall within a definite 'energy window'. The lower and upper limits of proton energies that can yield ECE spots in CR-39 have been experimentally determined to be ∼ 50 keV and ∼ 2.2 MeV under our processing conditions. To accomplish our objective, we have developed a technique based on ECE spot-density measurements in CR-39 detectors placed in conjuction with judiciously chosen thicknesses of a polyethylene radiator and a lead degrader. The optimum thicknesses of the radiator and the degrader, for a given neutron energy, are determined by computer calculations. (author)

  8. Multi-sphere unit cell model to calculate the effective thermal conductivity in pebble bed reactors

    International Nuclear Information System (INIS)

    Van Antwerpen, W.; Rousseau, P.G.; Du Toit, C.G.

    2010-01-01

    A proper understanding of the mechanisms of heat transfer, fluid flow and pressure drop through a packed bed of spheres is of utmost importance in the design of a high temperature Pebble Bed Reactor (PBR). While the gas flows predominantly in the axial direction through the bed, the total effective thermal conductivity is a lumped parameter that characterises the total heat transfer in the radial direction through the packed bed. The study of the effective thermal conductivity is important because it forms an intricate part of the self-acting decay heat removal chain, which is directly related to the PBR safety case. The effective thermal conductivity is the summation of various heat transport phenomena. These are the enhanced thermal conductivity due to turbulent mixing as the fluid passes through the voids between pebbles, heat transfer due to the movement of the solid spheres and thermal conduction and thermal radiation between the spheres in a stagnant fluid environment. In this study, the conduction and radiation between the spheres are investigated. Firstly, existing correlations for the effective thermal conductivity are investigated, with particular attention given to its applicability in the near-wall region. Several phenomena in particular are examined namely: conduction through the spheres, conduction through the contact area between the spheres, conduction through the gas phase and radiation between solid surfaces. A new approach to simulate the effective thermal conductivity for randomly packed beds is then presented, namely the so-called Multi-sphere Unit Cell Model. The model is validated by comparing the results with that obtained in experiments. (authors)

  9. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, the neutron polarization analyzer DNS, the neutron spin-echo spectrometer J-NSE, the small-angle neutron diffractometers KWS-1/-2, the very-small-angle neutron diffractometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  10. Measurements of neutron spectrum from uranium converter

    International Nuclear Information System (INIS)

    Ninkovic, M.; Sotic, O.; Marinkovic, S.

    1978-01-01

    The procedure for determination of energetic distribution of neutrons by the multisphere technique is given. The theoretical basis and features of the method are explained. The spectral distribution of neutrons emerging from the neutron converter constructed at the bare reactor assembly RB, has been determined applying the existing computer programme and literature data for the energetic dependence functions of spheres of various diameters. The obtained spectral distribution has a specific maximum in the domain of fast neutrons, justifying thus the reacton for the construction of the converter. The neutron spectrum data obtained and given in this report are very important for the use of the converter in neutron dosimetry and radiation protection, as well as in the radiobiology, shielding, reactor physics etc. (author)

  11. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Amgarou, K. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Domingo, C. [Grup de Recerca en Radiacions Ionitzants, Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Esposito, A.; Gentile, A.; Carinci, G. [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Russo, S. [INFN-Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, via S. Sofia 44, 95123 Catania (Italy)

    2011-10-21

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E<20 MeV if only polyethylene spheres are used, but can be extended to hundreds of MeV by including metal-loaded spheres (extended range BSS, indicated with ERBSS). With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, an ERBSS experiment was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0{sup o} and 90{sup o} with respect to the beam-line. Here the ERBSS of UAB (Universidad Autonoma de Barcelona-Grup de Fisica de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were exposed to characterize the 'forward' and 'sideward' proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and

  12. A System for the Automatic Control and the Elaboration of Information from a Neutron Spectrometer Utilizing a Numerical Calculator. UN COMPLESSO PER IL COMANDO AUTOMATICO E L'ELABORAZIONE DELLE INFORMAZIONI DI UNO SPETTROMETRO PER NEUTRONI UTILIZZANTE UN CALCOLATORE NUMERICO

    Energy Technology Data Exchange (ETDEWEB)

    de Agostino, E; Turko, B

    1963-06-01

    A fully automatized control system for neutron spectromcters is described. The system works with a 1620 type IBM data processing system, which prepares the instructions for spectrometer operation on punched tape. The measured data and all necessary instructions are printed out and punched on tape, ready for final treatment by the data processing system. (auth)

  13. The electron antineutrino angular correlation coefficient a in free neutron decay. Testing the standard model with the aSPECT-spectrometer

    International Nuclear Information System (INIS)

    Borg, Michael

    2011-01-01

    The β-decay of free neutrons is a strongly over-determined process in the Standard Model (SM) of Particle Physics and is described by a multitude of observables. Some of those observables are sensitive to physics beyond the SM. For example, the correlation coefficients of the involved particles belong to them. The spectrometer aSPECT was designed to measure precisely the shape of the proton energy spectrum and to extract from it the electron anti-neutrino angular correlation coefficient a. A first test period (2005/2006) showed the ''proof-of-principles''. The limiting influence of uncontrollable background conditions in the spectrometer made it impossible to extract a reliable value for the coefficient a (published in 2008). A second measurement cycle (2007/2008) aimed to under-run the relative accuracy of previous experiments (δa)/(a)=5%. I performed the analysis of the data taken there which is the emphasis of this doctoral thesis. A central point are background studies. The systematic impact of background on a was reduced to (δa (syst.) )/(a)=0.61 %. The statistical accuracy of the analyzed measurements is (δa (stat.) )/(a)∼1.4 %. Besides, saturation effects of the detector electronics were investigated which were initially observed. These turned out not to be correctable on a sufficient level. An applicable idea how to avoid the saturation effects is discussed in the last chapter. (orig.)

  14. 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

  15. Neutron beam instruments at Harwell

    International Nuclear Information System (INIS)

    Baston, A.H.; Harris, D.H.C.

    1978-11-01

    A list and brief descriptions are given of the neutron beam facilities for U.K. scientists at Harwell and in academic institutions, available under an agreement between the Science Research Council and AERE (Harwell). The list falls under the following headings: reactor instruments (single crystal diffractometers, powder diffractometers, triple axis spectrometers, time-of-flight cold neutron twin rotor spectrometer, beryllium filter spectrometer, MARX spectrometer, Harwell small-angle scattering spectrometer); LINAC instruments (total scattering spectrometer, back scattering spectrometer, active sample spectrometer, inelastic rotor spectrometer, constant Q spectrometer); ancillary equipment (cryostats, superconducting magnets, electromagnets, furnaces). (U.K.)

  16. In-beam test of the Boron-10 Multi-Grid neutron detector at the IN6 time-of-flight spectrometer at the ILL

    Energy Technology Data Exchange (ETDEWEB)

    Birch, J; Hultman, L; Höglund, C [Linköping University, Thin Film Physics Division, IFM, SE-581 83 Linköping (Sweden); Buffet, J-C; Clergeau, J-F; Correa, J; Van Esch, P; Ferraton, M; Guerard, B; Halbwachs, J; Khaplanov, A; Koza, M; Piscitelli, F; Zbiri, M [Institute Laue Langevin, Rue Jules Horowitz, FR-38000 Grenoble (France); Hall-Wilton, R [European Spallation Source ESS AB, P.O Box 176, SE-221 00 Lund (Sweden)

    2014-07-24

    A neutron detector concept based on solid layers of boron carbide enriched in {sup 10}B has been in development for the last few years as an alternative for {sup 3}He by collaboration between the ILL, ESS and Linköping University. This Multi-Grid detector uses layers of aluminum substrates coated with {sup 10}B{sub 4}C on both sides that are traversed by the incoming neutrons. Detection is achieved using a gas counter readout principle. By segmenting the substrate and using multiple anode wires, the detector is made inherently position sensitive. This development is aimed primarily at neutron scattering instruments with large detector areas, such as time-of-flight chopper spectrometers. The most recent prototype has been built to be interchangeable with the {sup 3}He detectors of IN6 at ILL. The {sup 10}B detector has an active area of 32 x 48cm{sup 2}. It was installed at the IN6 instrument and operated for several weeks, collecting data in parallel with the regularly scheduled experiments, thus providing the first side-by-side comparison with the conventional {sup 3}He detectors. Results include an efficiency comparison, assessment of the in-detector scattering contribution, sensitivity to gamma-rays and the signal-to-noise ratio in time-of-flight spectra. The good expected performance has been confirmed with the exception of an unexpected background count rate. This has been identified as natural alpha activity in aluminum. New convertor substrates are under study to eliminate this source of background.

  17. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2014-01-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  18. Development of a 'chronotron' for time of flight fast neutron spectrometer; Realisation d'un chronotron pour spectrometre a neutrons rapides par temps de vol

    Energy Technology Data Exchange (ETDEWEB)

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

    1958-10-15

    A chronotron using storage circuits of a 100 channels amplitude analyser has been developed in order to measure the time of flight of fast neutrons. A time dilatation is obtained by a distribution of 20 6BN6 tubes. The width at half maximum of prompt coincidences curve is 1,6.10{sup -9} s for {beta}-{gamma} coincidences from An{sup 198} and 2.10{sup -9} s for n-{alpha} coincidences from (d, t) reaction. (author) [French] En vue de realiser un spectrometre a neutrons rapides par temps de vol, un chronotron utilisant les circuits d'enregistrement d'un selecteur d'amplitude de 100 canaux a ete construit. Une dilatation du temps est obtenue a l'aide d'une distribution de 20 lampes 6BN6. La largeur a mi-hauteur de la courbe de resolution est 1,6.10{sup -9} s pour les coincidences {beta}-{gamma} de Au{sup 198} et 2.10{sup -9} s pour les coincidences n-{alpha} de la reaction (d, t). (auteur)

  19. Direct mass and lifetime measurements of neutron-rich nuclei up to A∼100 using the TOFI spectrometer at LAMPF

    International Nuclear Information System (INIS)

    Lind, V.G.

    1993-01-01

    This project was directed toward the study of neutron-rich nuclei using the experimental facilities at LAMPF, which is a part of LANL. The principal results of the investigation include the discovery of many new isotopes along with a measurement of their masses and in particular those nuclides in the Z = 7--19 and 14 --26 regions of the chart of the nuclides.Thirty-four new nuclides were detected and studied with their masses being measured with relatively high accuracy, and an additional twenty-six that were previously known and measured were remeasured to an improved accuracy. Besides providing new information about the mass surface in new and extended redons of the chart of the nuclides, this investigation enabled properties and previously unknown structure of some of the nuclei to be determined such as nuclear deformation among some of the nuclides. Also a study of the neutron pairing gaps and the proton pairing gaps among these nuclides was made. Other developments also achieved included instrument (TOFI) improvements and upgrades and theoretical investigations into the masses of the hadrons

  20. Construction of a time-of-flight neutron spectrometer for reaction angles 000 and study of the reaction 65Cu(p,xn) 65Zn for Esub(p)=26.7 MeV

    International Nuclear Information System (INIS)

    Holler, Y.

    1984-01-01

    At the Hamburg Isochronous Cyclotron a novel time-of-flight neutron spectrometer was designed, constructed, and tested by means of a for the planned application typical nuclear reaction. The apparature was optimized for the measurement of continuous, structure-deficient neutron spectra in a wide angular range at a reproducible, as low as possible scattering neutron background. Such a facility is fitted to the strengths of the Hamburg cyclotron and allows to study questions on the precompound emission and on the inelastic projectile ( 3 He) breakup. The final test was performed with the reaction 65 Cu(p,xn) 65 Zn at Esub(p)=26.7 MeV for which already comparable data over a smaller angular range were present. In the analysis of the measurement results performed regarding the precompound effects the hybrid-exciton model calculations let recognize essential deviations at high neutron energies in the range of the extreme reaction angles. (orig./HSI) [de

  1. A powerful modular versatile and low cost multiprocessor system for data acquisition and control of neutron spectrometers

    International Nuclear Information System (INIS)

    Koskas, G.

    1987-04-01

    This paper describes the new data acquisition and control systems of the neutron scattering instruments at the ORPHEE research reactor. The existing system has undergone a complete change: the original CAMAC system and minicomputer controlling each experiment have given way to commercial CPU boards and microcomputers like the IBM PC. The communication links between these 2 components are the IEEE 488 or RS 232 standards. Emphasis is placed on flexibility and modular nature of such a system which makes a maximum use of commercial products thus guaranteeing reliability and ease of use. A study of the requirements and evolutions, technical as well as philosophical, is detailed in order to demonstrate the motivation of the choice of the system architecture. A survey of the various hardware and software achievements and finally an overview on the future improvements is given [fr

  2. Monolithic spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rajic, Slobodan (Knoxville, TN); Egert, Charles M. (Oak Ridge, TN); Kahl, William K. (Knoxville, TN); Snyder, Jr., William B. (Knoxville, TN); Evans, III, Boyd M. (Oak Ridge, TN); Marlar, Troy A. (Knoxville, TN); Cunningham, Joseph P. (Oak Ridge, TN)

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  3. Application of the multisphere technique. Calibration and use of a modified Multiple Probe Detector

    International Nuclear Information System (INIS)

    Lalande, R.

    1966-11-01

    The study concerns the search for a portable, compact device with a great autonomy of operation, able to carry out precise measurements of fast neutrons in exclusion zones. A DSM-type multi-probe detector, which is self-contained and fully transistorized, have been studied; it includes a storage battery with a 30 hour autonomy and a buffering capability, a pulse amplifier, an integrator (sensitivity 4 c / s - 200 c / s - 2000 c / s), a totalizer to carry out counting on 5 mm, and a SNR fast neutron probe equipped with its preamplifier. Slightly modified, this device perfectly fulfills the operating conditions. Designed to precisely define the relationship between the flow and the dose intensity, it allows to calibrate any type of fast neutrons detector (e.g. BF 3 or unmodified DSM) that will respond correctly and will provide routine monitoring at a facility

  4. Neutron optics using transverse field neutron spin echo method

    International Nuclear Information System (INIS)

    Achiwa, Norio; Hino, Masahiro; Yamauchi, Yoshihiro; Takakura, Hiroyuki; Tasaki, Seiji; Akiyoshi, Tsunekazu; Ebisawa, Toru.

    1993-01-01

    A neutron spin echo (NSE) spectrometer with perpendicular magnetic field to the neutron scattering plane, using an iron yoke type electro-magnet has been developed. A combination of cold neutron guider, supermirror neutron polarizer of double reflection type and supermirror neutron analyser was adopted for the spectrometer. The first application of the NSE spectrometer to neutron optics by passing Larmor precessing neutrons through gas, solid and liquid materials of several different lengths which are inserted in one of the precession field have been examined. Preliminary NSE spectra of this sample geometry are discussed. (author)

  5. Contribution to the study of 14 MeV neutron scattering by {sup 12}C using a time-of-flight spectrometer (1963); Contribution a l'etude de la diffusion des neutrons de 14 MeV par {sup 12}C, a l'aide d'un spectrometre a temps de vol (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, P [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1963-07-15

    Experimental measurements of 14 MeV fast neutrons scattering by {sup 12}C by time-flight spectrometer, with a 1.7 n. sec over-all resolution. The excitation of the 7.65 MeV level is observed. (author) [French] Etude experimentate de la diffusion par {sup 12}C des neutrons rapides de 14 MeV a l'aide d'un spectrometre de resolution totale de 17 n/s. Observation de l'excitation du niveau 0+ de 7,65 MeV. (auteur)

  6. 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.

  7. Correlation spectrometer

    Science.gov (United States)

    Sinclair, Michael B [Albuquerque, NM; Pfeifer, Kent B [Los Lunas, NM; Flemming, Jeb H [Albuquerque, NM; Jones, Gary D [Tijeras, NM; Tigges, Chris P [Albuquerque, NM

    2010-04-13

    A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

  8. Multidimensional spectrometer

    Science.gov (United States)

    Zanni, Martin Thomas; Damrauer, Niels H.

    2010-07-20

    A multidimensional spectrometer for the infrared, visible, and ultraviolet regions of the electromagnetic spectrum, and a method for making multidimensional spectroscopic measurements in the infrared, visible, and ultraviolet regions of the electromagnetic spectrum. The multidimensional spectrometer facilitates measurements of inter- and intra-molecular interactions.

  9. UCN gravitational spectrometer

    International Nuclear Information System (INIS)

    Kawabata, Yuji

    1988-01-01

    Concept design is carried out of two types of ultra cold neutron scallering equipment using the fall-focusing principle. One of the systems comprises a vertical gravitational spectrometer and the other includes a horizontal gravitation analyzer. A study is made of their performance and the following results are obtained. Fall-focusing type ultra cold neutron scattering equipment can achieve a high accuracy for measurement of energy and momentum. Compared with conventional neutron scattering systems, this type of equipment can use neutron very efficiently because scattered neutrons within a larger solid angle can be used. The maximum solid angle is nearly 4π and 2π for the vertical and horizontal type, respectively. Another feature is that the size of equipment can be reduced. In the present concept design, the equipment is spherical with a diameter of about 1 m, as compared with NESSIE which is 6.7 m in length and 4.85 m in height with about the same accuracy. Two horizontal analyzers and a vertical spectroscope are proposed. They are suitable for angle-dependent non-elastic scattering in the neutron velocity range of 6∼15 m/s, pure elastic scattering in the range of 4∼7 m/s, or angle-integration non-elastic scattering in the range of 4∼15 m/s. (N.K.)

  10. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  11. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  12. Evaluation of the ROTAX spectrometer

    International Nuclear Information System (INIS)

    Tietze-Jaensch, H.; Schmidt, W.; Geick, R.

    1997-01-01

    After installation of the new-type rotating crystal analyser spectrometer ROTAX at ISIS, we report on practical experience and describe its current status. The rotating analyser technique works feasibly and reliably and provides an ultimate scan flexibility on a pulsed time-of-flight neutron spectrometer. The spinning analyser achieves a mulitplex advantage factor of ca. 50 without compromising the resolution of the instrument. Despite these instrument merits its individual beam position at ISIS has only an unsatisfactorily weak flux, thus hindering this instrument yet to become fully competitive with other high-performance neutron spectrometers based at high-flux reactors. However, we strongly recommend a ROTAX-type instrument to be emphasized when the instrumentation suite of the future European spallation source ESS will come under scrutiny. (orig.)

  13. Neutron wave optics studied with ultracold neutrons

    International Nuclear Information System (INIS)

    Steyerl, A.

    1984-01-01

    The author discusses experiments demonstrating or utilizing the wave properties of neutrons with wavelengths of about 100 nm. In particular the 'UCN gravity diffractometer' and the gravity spectrometer NESSIE (Neutronen-Schwerkraft-Spectrometrie) are illustrated. (Auth.)

  14. The Philippine spectrometer

    International Nuclear Information System (INIS)

    Juliano, J.O.

    1965-01-01

    A notable project for international collaboration, in which participants from Indonesia, Korea, Thailand, China and the Philippines are working together, has been launched in the Philippines with Indian assistance under the aegis of the Agency. This is a regional training and research programme using a neutron crystal spectrometer, which has been established since January 1965 at the Philippine Atomic Research Centre in Diliman, Quezon City, Philippines. It is called the IPA Project after the signatories to a five year trilateral agreement, namely, the Government of India,the Republic of the Philippines, and the International Atomic Energy Agency. The programme is administered by a Joint Committee composed of one representative each of the Philippines, India and the Agency. The objective of this cooperative venture is to establish a research centre on neutron diffraction in which scientists and technicians from any Member State of IAEA in South Asia, South-East Asia and Pacific, or Far East regions could come to participate in research and training. Studies in solid state physics, such a s the structure determination of alloys and organic crystals, studies on the orientation of magnetic moments in the lattice of magnetic substances, and other problems based on elastic and inelastic scattering of neutrons are undertaken. There are a number of research reactors in this region where neutron spectrometers can be utilized and the recent establishment of this cooperative international research and training programme has been a timely one for this area of the world. Indeed, a number of other countries have shown a strong growing interest in the development of the project

  15. BIS-2 spectrometer for search and investigation of narrow resonances

    International Nuclear Information System (INIS)

    Aleev, A.N.; Aref'ev, V.A.; Balandin, V.P.

    1989-01-01

    The configuration and main characteristics of the BIS-2 spectrometer are described. The spectrometer was intended to search for and to investigate charmed particles and narrow resonances produced in neutron-nucleus interactions. It was placed on a neutron beam of the Serpukhov accelerator. The Monte-Carlo simulated and experimentally measured characteristics of individual elements and the spectrometer as a whole are described. A brief review of the principal results based on the analysis of more than 10 7 neutron-nucleus interactions registered by means of the BIS-2 spectrometer is given. 34 refs.; 8 figs.; 5 tabs

  16. HISS spectrometer

    International Nuclear Information System (INIS)

    Greiner, D.E.

    1984-11-01

    This talk describes the Heavy Ion Spectrometer System (HISS) facility at the Lawrence Berkeley Laboratory's Bevalac. Three completed experiments and their results are illustrated. The second half of the talk is a detailed discussion of the response of drift chambers to heavy ions. The limitations of trajectory measurement over a large range in incident particle charge are presented

  17. Spectrometer gun

    Science.gov (United States)

    Waechter, David A.; Wolf, Michael A.; Umbarger, C. John

    1985-01-01

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  18. Improving neutron spectrometer performances through spatial and focusing effects: Investigation of spatial correlation focusing influence on the resolution in diffraction and phonon scattering experiments

    International Nuclear Information System (INIS)

    Popovici, M.

    1986-09-01

    A consistent treatment of the optics of three-axis spectrometers with curved perfect crystals, the gradient of lattice spacing accounted for, is presented. The mosaic crystal case is treated within the same computational scheme. From the computational point of view, the perfect crystals case is not the zero mosaic spread limit of the mosaic crystals case. The estimation of the residual line-widths in conditions of reciprocal-space focusing allows the discussion of the possibilities and limitations of using spatial correlation effects for improving spectrometer performances. A computer programme is presented which makes it possible to calculate both analytically and numerically the optimal arrangements and the deviations of the optimal parameter values. The optimization of parameters not involved in the analytically expressed reciprocal-space focusing conditions is also possible with this programme. The experimental results presented in this paper show that both the line-widths and the absolute intensities can also be described with reasonable accuracy for the perfect curved crystals case. It is shown experimentally that even at low-flux reactors one can obtain with the aid of perfect curved crystals good resolutions at measurable intensities which are generally higher than those obtainable in conventional spectrometers with flat mosaic crystals

  19. Triple axis spectrometers

    International Nuclear Information System (INIS)

    Clausen, K.N.

    1997-01-01

    Conventional triple-axis neutron spectroscopy was developed by Brockhouse over thirty years ago' and remains today a versatile and powerful tool for probing the dynamics of condensed matter. The original design of the triple axis spectrometer is technically simple and probes momentum and energy space on a point-by-point basis. This ability to systematically probe the scattering function in a way which only requires a few angles to be moved under computer control and where the observed data in general can be analysed using a pencil and graph paper or a simple fitting routine, has been essential for the success of the method. These constraints were quite reasonable at the time the technique was developed. Advances in computer based data acquisition, neutron beam optics, and position sensitive area detectors have been gradually implemented on many triple axis spectrometer spectrometers, but the full potential of this has not been fully exploited yet. Further improvement in terms of efficiency (beyond point by point inspection) and increased sensitivity (use of focusing optics whenever the problem allows it) could easily be up to a factor of 10-20 over present instruments for many problems at a cost which is negligible compared to that of increasing the flux of the source. The real cost will be in complexity - finding the optimal set-up for a given scan and interpreting the data as the they are taken. On-line transformation of the data for an appropriate display in Q, ω space and analysis tools will be equally important for this task, and the success of these new ideas will crucially depend on how well we solve these problems. (author)

  20. Neutron dosimetry at the intense neutron source (INS)

    International Nuclear Information System (INIS)

    Dierckx, R.

    1977-01-01

    The neutron monitoring consists of two parts: the spectral characterization and the fluence determination. The experimental measurements are combined with theoretical calculations. The following methods are proposed for determining the spectra: a telescope (np) spectrometer, a telescope 6 Li(nα)T spectrometer, spectrometers needing unfolding, time-of-flight technique, and multiple foil technique

  1. The Spectrometer

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2012-01-01

    In the fall of 1999 I was shown an Ocean Optics spectrometer-in-the-computer at St. Patricks College at Maynooth, Ireland, and thought that I had seen heaven. Of course, it could not resolve the sodium D-lines (I had done that many years before with a homemade wire diffraction grating), and I began to realize that inside was some familiar old…

  2. The response of a Bonner Sphere spectrometer to charged hadrons

    OpenAIRE

    Agosteo, S; Dimovasili, E; Fassò, A; Silari, M

    2004-01-01

    Bonner sphere spectrometers (BSSs) are employed in neutron spectrometry and dosimetry since many years. Recent developments have seen the addition to a conventional BSS of one or more detectors (moderator plus thermal neutron counter) specifically designed to improve the overall response of the spectrometer to neutrons above 10 MeV. These additional detectors employ a shell of material with a high mass number (such as lead) within the polyethylene moderator, in order to slow down high-energy ...

  3. Reactor neutron dosimetry

    International Nuclear Information System (INIS)

    Najzer, M.; Pauko, M.; Glumac, B.; Acquah, I.N.; Moskon, F.

    1977-01-01

    An analysis of requirements and possibilities for experimental neutron spectrum determination during the reactor pressure vessel surveil lance programme is given. Fast neutron spectrum and neutron dose rate were measured in the Fast neutron irradiation facility of our TRIGA reactor. It was shown that the facility can be used for calibration of neutron dosimeters and for irradiation of samples sensitive to neutron radiation. The investigation of the unfolding algorithm ITER was continued. Based on this investigations are two specialized unfolding program packages ITERAD and ITERGS written this year. They are able to unfold data from activation detectors and NaI(T1) gamma spectrometer respectively

  4. 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.

  5. A systematic approach to personnel neutron monitoring

    International Nuclear Information System (INIS)

    Griffith, R.V.; Hankins, D.E.

    1980-01-01

    In selection, calibration and interpretation of personnel neutron dosimeters used in radiation protection, adequate attention is often not given to matching the characteristics of the dosimeter with the quality of the neutron field. A particular concern is the use of albedo detectors which have little energy response similarity to the neutron dose equivalent conversion curve. At the Lawrence Livermore Laboratory we have developed a system for dosimeter calibration and neutron field characterization using Bonner spheres and remmeters. Rapid surveys of the work area with detectors in 3-in and 9-in polyethylene spheres establish a qualitative estimate of spectral variation found in the facility. We also use this data to determine the appropriate albedo dosimeter calibration factors. At several locations representing the spectral range, multisphere spectra measure-ments are made and the spectrum weighted dose equivalent rates calculated. These rates are compared with survey instrument results to establish correction factors for the relative over- or under-response expected from these instruments, particularly in highly moderated neutron fields where remmeters overrespond. We also use the spectral information to determine the appropriateness of dosimeters considered for future use. This technique has been applied at power reactors to provide information valuable to selection of proper personnel dosimeters. We find that the spectral range is sufficiently narrow that albedo detectors can be used with confidence. On the other hand, most of the dose occurs at energies below the effective threshold NTA film. (author)

  6. 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

  7. Evaluation of HOPG mounting possibilities for multiplexing spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Groitl, Felix, E-mail: felix.groitl@psi.ch [Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Bartkowiak, Marek [Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen (Switzerland); Bergmann, Ryan M. [Division Large Research Facilities, Paul Scherrer Institut, 5232 Villigen (Switzerland); Birk, Jonas Okkels [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Department of Physics, Technical University of Denmark (DTU), 2800 Kgs. Lyngby (Denmark); Markó, Márton [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Wigner Research Centre for Physics, Neutron Spectroscopy Department, 1525 Budapest (Hungary); Bollhalder, Alex; Graf, Dieter [Laboratory for Scientific Developments and Novel Materials, Paul Scherrer Institut, 5232 Villigen (Switzerland); Niedermayer, Christof [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Rüegg, Christian [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Department of Quantum Matter Physics, University of Geneva, 1211 Geneva (Switzerland); Rønnow, Henrik M. [Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne, 1015 Lausanne (Switzerland); Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark)

    2017-06-21

    Four different methods for mounting HOPG analyzer crystals on Si holders have been evaluated in the design process of the new multiplexing spectrometer CAMEA. Contrary to neutron optics used in standard spectrometers, the new instrument concept employs a series of analyzer segments behind each other where the neutrons have to pass through the bonding compound of the different analyzer crystals. The different methods, namely screws, shellac, indium soldering and clips, have been evaluated with regards to background, transmission, cooling, activation and handling. The results presented here will give valuable input for future CAMEA-type spectrometers currently planned and designed at various neutron sources.

  8. Evaluation of HOPG mounting possibilities for multiplexing spectrometers

    International Nuclear Information System (INIS)

    Groitl, Felix; Bartkowiak, Marek; Bergmann, Ryan M.; Birk, Jonas Okkels; Markó, Márton; Bollhalder, Alex; Graf, Dieter; Niedermayer, Christof; Rüegg, Christian; Rønnow, Henrik M.

    2017-01-01

    Four different methods for mounting HOPG analyzer crystals on Si holders have been evaluated in the design process of the new multiplexing spectrometer CAMEA. Contrary to neutron optics used in standard spectrometers, the new instrument concept employs a series of analyzer segments behind each other where the neutrons have to pass through the bonding compound of the different analyzer crystals. The different methods, namely screws, shellac, indium soldering and clips, have been evaluated with regards to background, transmission, cooling, activation and handling. The results presented here will give valuable input for future CAMEA-type spectrometers currently planned and designed at various neutron sources.

  9. The high-resolution time-of-flight spectrometer TOFTOF

    Energy Technology Data Exchange (ETDEWEB)

    Unruh, Tobias [Technische Universitaet Muenchen, Forschungsneutronenquelle Heinz Maier-Leibnitz FRM II and Physik Department E13, Lichtenbergstr. 1, 85747 Garching (Germany)], E-mail: Tobias.Unruh@frm2.tum.de; Neuhaus, Juergen; Petry, Winfried [Technische Universitaet Muenchen, Forschungsneutronenquelle Heinz Maier-Leibnitz FRM II and Physik Department E13, Lichtenbergstr. 1, 85747 Garching (Germany)

    2007-10-11

    The TOFTOF spectrometer is a multi-disc chopper time-of-flight spectrometer for cold neutrons at the research neutron source Heinz Maier-Leibnitz (FRM II). After five reactor cycles of routine operation the characteristics of the instrument are reported in this article. The spectrometer features an excellent signal to background ratio due to its remote position in the neutron guide hall, an elaborated shielding concept and an s-shaped curved primary neutron guide which acts i.a. as a neutron velocity filter. The spectrometer is fed with neutrons from the undermoderated cold neutron source of the FRM II leading to a total neutron flux of {approx}10{sup 10}n/cm{sup 2}/s in the continuous white beam at the sample position distributed over a continuous and particularly broad wavelength spectrum. A high energy resolution is achieved by the use of high speed chopper discs made of carbon-fiber-reinforced plastic. In the combination of intensity, resolution and signal to background ratio the spectrometer offers new scientific prospects in the fields of inelastic and quasielastic neutron scattering.

  10. The high-resolution time-of-flight spectrometer TOFTOF

    Science.gov (United States)

    Unruh, Tobias; Neuhaus, Jürgen; Petry, Winfried

    2007-10-01

    The TOFTOF spectrometer is a multi-disc chopper time-of-flight spectrometer for cold neutrons at the research neutron source Heinz Maier-Leibnitz (FRM II). After five reactor cycles of routine operation the characteristics of the instrument are reported in this article. The spectrometer features an excellent signal to background ratio due to its remote position in the neutron guide hall, an elaborated shielding concept and an s-shaped curved primary neutron guide which acts i.a. as a neutron velocity filter. The spectrometer is fed with neutrons from the undermoderated cold neutron source of the FRM II leading to a total neutron flux of ˜1010n/cm2/s in the continuous white beam at the sample position distributed over a continuous and particularly broad wavelength spectrum. A high energy resolution is achieved by the use of high speed chopper discs made of carbon-fiber-reinforced plastic. In the combination of intensity, resolution and signal to background ratio the spectrometer offers new scientific prospects in the fields of inelastic and quasielastic neutron scattering.

  11. Realization of two light particle correlation experiments: behaviour to very low relative momenta (measurement with a magnetic spectrometer) and influence of the violence of reaction on the emission sources (measured by the neutron detector ORION

    International Nuclear Information System (INIS)

    Sezac, L.

    1993-01-01

    The correlation measurements between light particles emitted during heavy ion collisions allow to estimate the time-space extension of the emitting sources. This report about the preliminaries of two correlation experiments is split into two parts. The first one describes a test experiment, performed to study the feasibility of a correlation experiment at very low relative momenta with the help of a magnetic spectrometer. The results will allow to determine the still unknown relative effects from the final state interaction and the combination of both Coulomb interaction and quantum statistics. A correlation study without experimental selection of the impact parameter gives unclear answers about the sizes and the temporal characteristics of the emitting systems. The second part analyses the sources of the alpha particles detected in the reaction chamber of the multidetector ORION used as a violence of the reaction filter. The results show that it is possible to consider as a good filter a fast information called 'prompt peak' (correlated to the neutron multiplicity detected with ORION). Under such conditions a study of two particle correlations from equilibrated systems with a reasonable statistics becomes thinkable. The results obtained allow to characterize the emitting sources (speed, intensity, temperature) as a function of the violence of the reaction for the system 208 Pb + 93 Nb at 29 MeV/u. (author)

  12. Mass measurements on neutron-deficient nuclides at SHIPTRAP and commissioning of a cryogenic narrow-band FT-ICR mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer Garcia, R.

    2007-07-01

    The dissertation presented here deals with high-precision Penning trap mass spectrometry on short-lived radionuclides. Owed to the ability of revealing all nucleonic interactions, mass measurements far off the line of {beta}-stability are expected to bring new insight to the current knowledge of nuclear properties and serve to test the predictive power of mass models and formulas. In nuclear astrophysics, atomic masses are fundamental parameters for the understanding of the synthesis of nuclei in the stellar environments. This thesis presents ten mass values of radionuclides around A=90 interspersed in the predicted rp-process pathway. Six of them have been experimentally determined for the first time. The measurements have been carried out at the Penning-trap mass spectrometer SHIPTRAP using the destructive time-of-flight ion-cyclotron-resonance (TOF-ICR) detection technique. Given the limited performance of the TOF-ICR detection when trying to investigate heavy/superheavy species with small production cross sections ({sigma} <1 {mu}b), a new detection system is found to be necessary. Thus, the second part of this thesis deals with the commissioning of a cryogenic double-Penning trap system for the application of a highly-sensitive, narrow-band Fourier-transform ion-cyclotron-resonance (FT-ICR) detection technique. With the non-destructive FT-ICR detection method a single singly-charged trapped ion will provide the required information to determine its mass. First off-line tests of a new detector system based on a channeltron with an attached conversion dynode, of a cryogenic pumping barrier, to guarantee ultra-high vacuum conditions during mass determination, and of the detection electronics for the required single-ion sensitivity are reported. (orig.)

  13. Small angle spectrometers: Summary

    International Nuclear Information System (INIS)

    Courant, E.; Foley, K.J.; Schlein, P.E.

    1986-01-01

    Aspects of experiments at small angles at the Superconducting Super Collider are considered. Topics summarized include a small angle spectrometer, a high contingency spectrometer, dipole and toroid spectrometers, and magnet choices

  14. The VESUVIO Spectrometer Now and When?

    International Nuclear Information System (INIS)

    Seel, A G; Krzystyniak, M; Fernandez-Alonso, F

    2014-01-01

    The current layout and mechanics of the VESUVIO spectrometer are presented in light of spectroscopic measurements using electron-volt neutrons. A brief background to the theoretical framework of deep inelastic neutron scattering is presented, with focus on data collection and instrumental design. The current capabilities and research themes for VESUVIO are discussed, and possible future instrumental developments highlighted which will enhance the instrument's ability to meet scientific inquiry and expectation

  15. The VESUVIO Spectrometer Now and When?

    Science.gov (United States)

    Seel, A. G.; Krzystyniak, M.; Fernandez-Alonso, F.

    2014-12-01

    The current layout and mechanics of the VESUVIO spectrometer are presented in light of spectroscopic measurements using electron-volt neutrons. A brief background to the theoretical framework of deep inelastic neutron scattering is presented, with focus on data collection and instrumental design. The current capabilities and research themes for VESUVIO are discussed, and possible future instrumental developments highlighted which will enhance the instrument's ability to meet scientific inquiry and expectation.

  16. Smartphone Spectrometers

    Science.gov (United States)

    Willmott, Jon R.; Mims, Forrest M.; Parisi, Alfio V.

    2018-01-01

    Smartphones are playing an increasing role in the sciences, owing to the ubiquitous proliferation of these devices, their relatively low cost, increasing processing power and their suitability for integrated data acquisition and processing in a ‘lab in a phone’ capacity. There is furthermore the potential to deploy these units as nodes within Internet of Things architectures, enabling massive networked data capture. Hitherto, considerable attention has been focused on imaging applications of these devices. However, within just the last few years, another possibility has emerged: to use smartphones as a means of capturing spectra, mostly by coupling various classes of fore-optics to these units with data capture achieved using the smartphone camera. These highly novel approaches have the potential to become widely adopted across a broad range of scientific e.g., biomedical, chemical and agricultural application areas. In this review, we detail the exciting recent development of smartphone spectrometer hardware, in addition to covering applications to which these units have been deployed, hitherto. The paper also points forward to the potentially highly influential impacts that such units could have on the sciences in the coming decades. PMID:29342899

  17. Smartphone Spectrometers

    Directory of Open Access Journals (Sweden)

    Andrew J.S. McGonigle

    2018-01-01

    Full Text Available Smartphones are playing an increasing role in the sciences, owing to the ubiquitous proliferation of these devices, their relatively low cost, increasing processing power and their suitability for integrated data acquisition and processing in a ‘lab in a phone’ capacity. There is furthermore the potential to deploy these units as nodes within Internet of Things architectures, enabling massive networked data capture. Hitherto, considerable attention has been focused on imaging applications of these devices. However, within just the last few years, another possibility has emerged: to use smartphones as a means of capturing spectra, mostly by coupling various classes of fore-optics to these units with data capture achieved using the smartphone camera. These highly novel approaches have the potential to become widely adopted across a broad range of scientific e.g., biomedical, chemical and agricultural application areas. In this review, we detail the exciting recent development of smartphone spectrometer hardware, in addition to covering applications to which these units have been deployed, hitherto. The paper also points forward to the potentially highly influential impacts that such units could have on the sciences in the coming decades.

  18. Evaluation of HOPG mounting possibilities for multiplexing spectrometers

    DEFF Research Database (Denmark)

    Groitl, Felix; Bartkowiak, Marek; Bergmann, Ryan M.

    2017-01-01

    Four different methods for mounting HOPG analyzer crystals on Si holders have been evaluated in the design process of the new multiplexing spectrometer CAMEA. Contrary to neutron optics used in standard spectrometers, the new instrument concept employs a series of analyzer segments behind each...

  19. Tests of a prototype resonance filter spectrometer at WNR

    International Nuclear Information System (INIS)

    Newport, R.J.; Seeger, P.A.; Williams, W.G.

    1984-11-01

    Data gained during a series of developmental experiments using the SNS test resonance filter spectrometer at the WNR pulsed neutron facility, Los Alamos, are presented and discussed. The operational experience obtained during the period of these studies has provided some insight into the desirable characteristics and possible limitations of any future spectrometer design and this information is considered in some detail. (author)

  20. SMARTS - a spectrometer for strain measurement in engineering materials

    Energy Technology Data Exchange (ETDEWEB)

    Bourke, M.A.M. [MS H805, Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Dunand, D.C. [Department of Materials Science and Engineering, Northwestern University, Cook Hall, Evanston, IL, 60208 (United States); Ustundag, E. [Department of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States)

    2002-07-01

    A new spectrometer called SMARTS (Spectrometer for Materials Research at Temperature and Stress) has been commissioned at the Los Alamos neutron science center and entered the user program in August of 2002. Its design maximizes capability and throughput for measurements of (a) residual macrostrain in engineering components and (b) in situ loading. This paper describes some aspects of the instrument. (orig.)

  1. SMARTS - a spectrometer for strain measurement in engineering materials

    CERN Document Server

    Bourke, M A M; Ustundag, E

    2002-01-01

    A new spectrometer called SMARTS (Spectrometer for Materials Research at Temperature and Stress) has been commissioned at the Los Alamos neutron science center and entered the user program in August of 2002. Its design maximizes capability and throughput for measurements of (a) residual macrostrain in engineering components and (b) in situ loading. This paper describes some aspects of the instrument. (orig.)

  2. Triple-axis spectrometer DruechaL

    International Nuclear Information System (INIS)

    Buehrer, W.; Keller, P.

    1996-01-01

    DruechaL is a triple-axis spectrometer located at a cold guide. The characteristics of guide and instrument allow the use of a broad spectral range of neutrons. The resolution in momentum and energy transfer can be tuned to match the experimental requirements by using either collimators or focusing systems (monochromator, antitrumpet, analyser). (author) figs., tabs., refs

  3. Triple-axis spectrometer DruechaL

    Energy Technology Data Exchange (ETDEWEB)

    Buehrer, W; Keller, P [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    DruechaL is a triple-axis spectrometer located at a cold guide. The characteristics of guide and instrument allow the use of a broad spectral range of neutrons. The resolution in momentum and energy transfer can be tuned to match the experimental requirements by using either collimators or focusing systems (monochromator, antitrumpet, analyser). (author) figs., tabs., refs.

  4. Status of neutron complex of INR RAS

    Energy Technology Data Exchange (ETDEWEB)

    Grachev, M I; Koptelov, E A; Kravchuk, L V; Matveev, V A; Perekrestenko, A D; Sidorkin, S F [Institute for Nuclear Research of Russian Academy of Sciences, Prospekt, Moscow (Russian Federation); Stavissky, Y Y

    2001-03-01

    The neutron complex of INR RAS consists of two sources of neutrons, beam stop, lead slowing down spectrometer and solid state spectrometers. The description of objects and their condition, the program of planned researches, co-operation with other institutes of the Moscow Region, progress reached for last two years are introduced in the article. (author)

  5. Status of neutron complex of INR RAS

    International Nuclear Information System (INIS)

    Grachev, M.I.; Koptelov, E.A.; Kravchuk, L.V.; Matveev, V.A.; Perekrestenko, A.D.; Sidorkin, S.F.; Stavissky, Y.Y.

    2001-01-01

    The neutron complex of INR RAS consists of two sources of neutrons, beam stop, lead slowing down spectrometer and solid state spectrometers. The description of objects and their condition, the program of planned researches, co-operation with other institutes of the Moscow Region, progress reached for last two years are introduced in the article. (author)

  6. Polarized triple-axis spectrometer TASP

    Energy Technology Data Exchange (ETDEWEB)

    Boeni, P; Keller, P [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    The polarized triple-axis spectrometer TASP at SINQ has been optimized for measuring magnetic cross sections in condensed matter. The neutrons are polarized or analyzed either by means of benders or Heusler monochromators. The beam divergence, i.e. the intensity, and the spectral range of the neutrons is rather large because of the supermirror coatings of the feeding neutron guide. The intensity can be further increased at the sample position by means of a focussing monochromator and a focussing anti-trumpet. The end position of TASP allows the tailoring of the neutron beam already before the monochromator and to scatter neutrons over very wide ranges of angles. (author) 6 figs., 1 tab., 8 refs.

  7. RITA-type triple axis spectrometers

    International Nuclear Information System (INIS)

    Roennow, H.M.

    2001-01-01

    The RITA spectrometer at Risoe National Laboratory was the first to incorporate a complete re-thinking of the neutron-path from source, through detector to analysis. Since then, other RITA-type spectrometers such as SPINS at NIST, RITA-II at PSI have been built, and several new spectrometers around the world are adapting the same philosophy. The main novelty of RITA was the introduction of a single back-end tank featuring both an analyser block with multiple individually turnable analyser blades and a 2D position sensitive detector. Several new triple-axis spectrometers are presently being built at existing and future sources, and almost all of them have learnt from the experience with RITA. (R.P.)

  8. The development for small scale soft X-ray spectrometer

    International Nuclear Information System (INIS)

    Sun Kexu; Jiang Shaoen; Yi Rongqing; Cui Yanli

    2004-12-01

    For the development of small-scale soft X-ray spectrometer, first, some small-scale soft X-ray detection elements are developed, it is included GaAs irradiated with neutron, GaAs irradiated with proton, multi-layer mirror, plane mirror and small scale X-ray diode et al. Soft X-ray spectrometers built of multi-layer mirror-GaAs (with neutron irradiation), and plane mirror-small-scale XRD, and plane mirror-GaAs (with proton irradiation) are prepared. These spectrometers are examined in Shen Guang-II laser facility, and some external estimation are given. (authors)

  9. Current status of neutron scattering in Thailand

    International Nuclear Information System (INIS)

    Ampornrat, Pantip

    2000-01-01

    The neutron scattering experiments in Thailand have been done continuously since the start up of the reactor. In 1977, Thai research reactor was modified into TRIGA MARK III core. After that, the neutron spectrometer was installed again under a development program. Installation of upgrading spectrometer was delayed because of some problems involving the neutron intensity and instruments. However, these problems were solved and the setup is almost completed. The paper reports the current status of neutron spectrometer, the problems and plans for the experiments. (author)

  10. Insight on agglomerates of gold nanoparticles in glass based on surface plasmon resonance spectrum: study by multi-spheres T-matrix method

    Science.gov (United States)

    Avakyan, L. A.; Heinz, M.; Skidanenko, A. V.; Yablunovski, K. A.; Ihlemann, J.; Meinertz, J.; Patzig, C.; Dubiel, M.; Bugaev, L. A.

    2018-01-01

    The formation of a localized surface plasmon resonance (SPR) spectrum of randomly distributed gold nanoparticles in the surface layer of silicate float glass, generated and implanted by UV ArF-excimer laser irradiation of a thin gold layer sputter-coated on the glass surface, was studied by the T-matrix method, which enables particle agglomeration to be taken into account. The experimental technique used is promising for the production of submicron patterns of plasmonic nanoparticles (given by laser masks or gratings) without damage to the glass surface. Analysis of the applicability of the multi-spheres T-matrix (MSTM) method to the studied material was performed through calculations of SPR characteristics for differently arranged and structured gold nanoparticles (gold nanoparticles in solution, particles pairs, and core-shell silver-gold nanoparticles) for which either experimental data or results of the modeling by other methods are available. For the studied gold nanoparticles in glass, it was revealed that the theoretical description of their SPR spectrum requires consideration of the plasmon coupling between particles, which can be done effectively by MSTM calculations. The obtained statistical distributions over particle sizes and over interparticle distances demonstrated the saturation behavior with respect to the number of particles under consideration, which enabled us to determine the effective aggregate of particles, sufficient to form the SPR spectrum. The suggested technique for the fitting of an experimental SPR spectrum of gold nanoparticles in glass by varying the geometrical parameters of the particles aggregate in the recurring calculations of spectrum by MSTM method enabled us to determine statistical characteristics of the aggregate: the average distance between particles, average size, and size distribution of the particles. The fitting strategy of the SPR spectrum presented here can be applied to nanoparticles of any nature and in various

  11. Neutron scattering in Indonesia. Country report

    Energy Technology Data Exchange (ETDEWEB)

    Ikram, Abarrul [Neutron Scattering Laboratory, R and D Center for Materials Science and Technology, National Nuclear Energy Agency, Serpong (Indonesia)

    2000-10-01

    Neutron scattering in Indonesia is still alienated due to some reasons and conditions which are discussed. The reactor and its latest operation mode are also described. The neutron beam facilities which include one diffractometer for residual stress measurement, one diffractometer for single crystal structural determination and texture measurement, one high resolution powder diffractometer, one neutron radiography facility, one triple axis spectrometer, one small angle neutron scattering spectrometer and one high resolution small angle neutron scattering spectrometer were presented briefly together with improvements of neutron intensities at some spectrometers in connection with the setting of main beam shutter position. Special attention is given for four instruments mostly related to this workshop. Their performances and problems faced in the past 9 months are presented as well as the future plan for refurbishment and development. (author)

  12. Associated Particle Tagging (APT) in Magnetic Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, David V.; Baciak, James E.; Stave, Sean C.; Chichester, David; Dale, Daniel; Kim, Yujong; Harmon, Frank

    2012-10-16

    Summary In Brief The Associated Particle Tagging (APT) project, a collaboration of Pacific Northwest National Laboratory (PNNL), Idaho National Laboratory (INL) and the Idaho State University (ISU)/Idaho Accelerator Center (IAC), has completed an exploratory study to assess the role of magnetic spectrometers as the linchpin technology in next-generation tagged-neutron and tagged-photon active interrogation (AI). The computational study considered two principle concepts: (1) the application of a solenoidal alpha-particle spectrometer to a next-generation, large-emittance neutron generator for use in the associated particle imaging technique, and (2) the application of tagged photon beams to the detection of fissile material via active interrogation. In both cases, a magnetic spectrometer momentum-analyzes charged particles (in the neutron case, alpha particles accompanying neutron generation in the D-T reaction; in the tagged photon case, post-bremsstrahlung electrons) to define kinematic properties of the relevant neutral interrogation probe particle (i.e. neutron or photon). The main conclusions of the study can be briefly summarized as follows: Neutron generator: • For the solenoidal spectrometer concept, magnetic field strengths of order 1 Tesla or greater are required to keep the transverse size of the spectrometer smaller than 1 meter. The notional magnetic spectrometer design evaluated in this feasibility study uses a 5-T magnetic field and a borehole radius of 18 cm. • The design shows a potential for 4.5 Sr tagged neutron solid angle, a factor of 4.5 larger than achievable with current API neutron-generator designs. • The potential angular resolution for such a tagged neutron beam can be less than 0.5o for modest Si-detector position resolution (3 mm). Further improvement in angular resolution can be made by using Si-detectors with better position resolution. • The report documents several features of a notional generator design incorporating the

  13. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 77; Issue 4. Issue front cover thumbnail. Volume 77, Issue 4. October 2011, pages 599-764. pp 599-609 Research Articles. Evaluation of response matrix of a multisphere neutron spectrometer with water moderator · Rahim Khabaz Hashem Miri Hakimabad.

  14. Proceedings of the international workshop on new opportunities in single crystal spectroscopy with neutrons

    International Nuclear Information System (INIS)

    Fuezi, J.; Rosta, L.

    2001-08-01

    The Conference Proceedings contains 19 papers on neutron scattering research facilities, neutron sources, scattering spectrometers, detectors, and use of neutron scattering in solid state research. 14 papers were indexed and abstracted for the INIS database. (R.P.)

  15. VERITAS: Versatile Triple-Axis Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il

    2006-04-15

    Korea Atomic Energy Research Institute is planning to build a cold neutron triple-axis spectrometer at HANARO, the 30 MW research reactor. The spectrometer is expected to be completed in 2008 with the following configuration from the upstream to the downstream. Guide Supermirror m = 2, In-pile Straight Section, {approx} 5 m Curved Guide, {approx} 26 m w/ R 1500 m Straight Guide before the Instrument, {approx} 40 m Filters PG and Be Neutron Velocity Selector (Future) Monochromators Vertically Focusing Monochromators PG(002) and Heusler(111) Doubly Focusing Monochromators (Future) Monochromator-Sample Distance 2 m Collimation C1 Soller Collimators, 20', 40' 80'Beam Height at the Sample Table 1.5 m Sample-Analyzer Distance 1.0 m Collimation C2 Soller Collimators, 20', 40', 80' Radial Collimator Analyzers Horizontally Focusing Analyzers w/ Fixed Vertical Focusing PG(002) and Heusler(111) Analyzer-Detector Distance 0.5 m Detectors 5 cm Tube Detector 25 cm wide Position Sensitive Detector Once completed, the neutron flux at sample is expected to surpass that of SPINS at NCNR, making this instrument one of the most powerful 2nd generation cold neutron triple-axis spectrometers in the world.

  16. VERITAS: Versatile Triple-Axis Spectrometer

    International Nuclear Information System (INIS)

    Park, Sung Il

    2006-04-01

    Korea Atomic Energy Research Institute is planning to build a cold neutron triple-axis spectrometer at HANARO, the 30 MW research reactor. The spectrometer is expected to be completed in 2008 with the following configuration from the upstream to the downstream. Guide Supermirror m = 2, In-pile Straight Section, ∼ 5 m Curved Guide, ∼ 26 m w/ R 1500 m Straight Guide before the Instrument, ∼ 40 m Filters PG and Be Neutron Velocity Selector (Future) Monochromators Vertically Focusing Monochromators PG(002) and Heusler(111) Doubly Focusing Monochromators (Future) Monochromator-Sample Distance 2 m Collimation C1 Soller Collimators, 20', 40' 80'Beam Height at the Sample Table 1.5 m Sample-Analyzer Distance 1.0 m Collimation C2 Soller Collimators, 20', 40', 80' Radial Collimator Analyzers Horizontally Focusing Analyzers w/ Fixed Vertical Focusing PG(002) and Heusler(111) Analyzer-Detector Distance 0.5 m Detectors 5 cm Tube Detector 25 cm wide Position Sensitive Detector Once completed, the neutron flux at sample is expected to surpass that of SPINS at NCNR, making this instrument one of the most powerful 2nd generation cold neutron triple-axis spectrometers in the world

  17. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  18. Resolution function in neutron diffractometry

    International Nuclear Information System (INIS)

    Popa, N.

    1987-01-01

    The resolution function in the neutron diffractometry is defined, on base of generalizing the resolution formerly formulated for the double axis neutron spectrometer. A polemical discussion is raised concerning an approach to this function existent in literature. The actual approach is concretized for the DN-2 time-of-flight diffractometer installed at the IBR-2 reactor

  19. High-precision spectrometer for studies of ion-induced and spontaneous fission dynamics

    International Nuclear Information System (INIS)

    Batenkov, O.; Elmgren, K.; Majorov, M.; Blomgren, J.; Conde, H.; Hultqvist, S.; Olsson, N.; Rahm, J.; Ramstroem, E.; Smirnov, S.; Veshikov, A.

    1997-01-01

    A spectrometer has been designed and built to investigate the dynamics of spontaneous and ion-induced fission processes. It consists of 8 neutron detectors surrounding a low mass scattering chamber containing the fissionable targets and two fission fragment telescopes. The spectrometer measures neutron spectra, and energy and angular correlations of neutrons, as well as kinetic energy, mass, and relative angle of fission fragments. A 252 Cf fission reference source is used for calibration. (orig.)

  20. Neutron guides and scientific neutron equipment at CILAS/GMI

    International Nuclear Information System (INIS)

    Gautier-Picard, P.

    2003-01-01

    CILAS company is the world's leading supplier of complete neutron guides systems. The neutron optics with multilayer coatings produced by CILAS have become an international standard for neutron beam transportation in the modern research institutes. During the last 30 years, CILAS designed, produced and installed more than 5000 meters of guides in many European, American and Asian countries. To reinforce its leadership and presence in neutron research, CILAS acquired the company Grenoble Modular Instruments (GMI), a leading company in high precision mechanics, engineering and manufacturing of spectrometers and scientific equipment for neutron and synchrotron research. (author)

  1. The Triple Axis and SPINS Spectrometers.

    Science.gov (United States)

    Trevino, S F

    1993-01-01

    In this paper are described the triple axis and spin polarized inelastic neutron scattering (SPINS) spectrometers which are installed at the NIST Cold Neutron Research Facility (CNRF). The general principle of operation of these two instruments is described in sufficient detail to allow the reader to make an informed decision as to their usefulness for his needs. However, it is the intention of the staff at the CNRF to provide the expert resources for their efficient use in any given situation. Thus, this work is not intended as a user manual but rather as a guide into the range of applicability of the two instruments.

  2. A large angle cold neutron bender using sequential garland reflections for pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Ebisawa, T.; Tasaki, S. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Soyama, K.; Suzuki, J. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    We discuss a basic structure and performance of a new cold neutron bender using sequential garland reflections, in order to bend a neutron beam with large divergence by large angle. Using this bender for a pulsed neutron source we could not only avoid the frame overlap for cold neutrons but also install a plural spectrometers at a cold guide and obtain polarized neutron beams if necessary. (author)

  3. A large angle cold neutron bender using sequential garland reflections for pulsed neutron source

    International Nuclear Information System (INIS)

    Ebisawa, T.; Tasaki, S.; Soyama, K.; Suzuki, J.

    2001-01-01

    We discuss a basic structure and performance of a new cold neutron bender using sequential garland reflections, in order to bend a neutron beam with large divergence by large angle. Using this bender for a pulsed neutron source we could not only avoid the frame overlap for cold neutrons but also install a plural spectrometers at a cold guide and obtain polarized neutron beams if necessary. (author)

  4. Spherical grating spectrometers

    Science.gov (United States)

    O'Donoghue, Darragh; Clemens, J. Christopher

    2014-07-01

    We describe designs for spectrometers employing convex dispersers. The Offner spectrometer was the first such instrument; it has almost exclusively been employed on satellite platforms, and has had little impact on ground-based instruments. We have learned how to fabricate curved Volume Phase Holographic (VPH) gratings and, in contrast to the planar gratings of traditional spectrometers, describe how such devices can be used in optical/infrared spectrometers designed specifically for curved diffraction gratings. Volume Phase Holographic gratings are highly efficient compared to conventional surface relief gratings; they have become the disperser of choice in optical / NIR spectrometers. The advantage of spectrometers with curved VPH dispersers is the very small number of optical elements used (the simplest comprising a grating and a spherical mirror), as well as illumination of mirrors off axis, resulting in greater efficiency and reduction in size. We describe a "Half Offner" spectrometer, an even simpler version of the Offner spectrometer. We present an entirely novel design, the Spherical Transmission Grating Spectrometer (STGS), and discuss exemplary applications, including a design for a double-beam spectrometer without any requirement for a dichroic. This paradigm change in spectrometer design offers an alternative to all-refractive astronomical spectrometer designs, using expensive, fragile lens elements fabricated from CaF2 or even more exotic materials. The unobscured mirror layout avoids a major drawback of the previous generation of catadioptric spectrometer designs. We describe laboratory measurements of the efficiency and image quality of a curved VPH grating in a STGS design, demonstrating, simultaneously, efficiency comparable to planar VPH gratings along with good image quality. The stage is now set for construction of a prototype instrument with impressive performance.

  5. Using multi spherical spectrometry for determination of dosimetric characteristics of mixed neutron and gamma radiation fields of fission sources

    International Nuclear Information System (INIS)

    Fyulep, M.; Nikodemova, D.; Grabovtsova, A.; Galan, P.; Trousil, J.

    1977-01-01

    Possibilities of the application of multispherical spectrometry in personnel dosimetry of neutrons (n) and gamma radiation (γ) are considered. Studies were made to elucidate a possibility of using albedo dosemeters to increase the sensitivity of personnel dosemeters. Determined were the dose due to the (n,γ) reaction in a human body, absorbed dose and dose equivalent. The effect of (n,γ) dose on the reading of personnel gamma dosemeter was considered. It is shown that the above effect on the dosemeter readings for frontal irradiation by a broad neutron beam in everyday personnel dosimetry near 252 Cf sources may be neglected. Only in the case of strongly slowed-down fission spectrum the effect of the (n,γ) reaction is considerable. The application of albedo dosemeter is expedient to take into account the corrections of personnel dosemeter readings [ru

  6. An intense transmission spectrometer for ISIS

    International Nuclear Information System (INIS)

    Newport, R.J.; Howells, W.S.

    1986-07-01

    The report seeks to outline a design for an intense transmission spectrometer (ITS) suitable for installation on the pulsed neutron source ISIS. The performance of the instrument is evaluated and several examples of the areas of science made accessible are discussed. It is shown that the proposed design will represent a scientifically valuable and cost-effective addition to the present suite of ISIS instruments. (author)

  7. 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)

  8. Resolution of a triple axis spectrometer

    DEFF Research Database (Denmark)

    Nielsen, Mourits; Bjerrum Møller, Hans

    1969-01-01

    A new method for obtaining the resolution function for a triple-axis neutron spectrometer is described, involving a combination of direct measurement and analytical calculation. All factors which contribute to the finite resolution of the instrument may be taken into account, and Gaussian...... or experimentally determined probability distributions may be used. The application to the study of the dispersion relation for excitations in a crystal is outlined...

  9. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  10. Bonner sphere spectrometer for characterization of BNCT beam

    Energy Technology Data Exchange (ETDEWEB)

    Marek, Milan, E-mail: mam@nri.cz [Nuclear Research Institute Rez, Husinec 130, 25068 Husinec-Rez (Czech Republic); Viererbl, Ladislav [Nuclear Research Institute Rez, Husinec 130, 25068 Husinec-Rez (Czech Republic)

    2011-12-15

    The characterization of the epithermal beam is performed by different dosimetry techniques that give information on neutron flux as well as neutron and photon doses. One of the possible methods is based on the measurement of thermal neutrons in a moderation environment, which enables the evaluation of neutron flux in a group structure and also neutron dose. The advantage of such a spectrometer consists of the fact that 90% response intervals of the spheres continuously cover the epithermal part of the neutron energy range. The method has been applied to characterize the epithermal neutron beams at several research centers in USA, Finland, the Netherlands and Czech Republic. The comparison of the MIT FCB, HFR HB11, VTT FiR, and LVR-15 beam parameters is presented in this paper.

  11. The SPEDE spectrometer

    Science.gov (United States)

    Papadakis, P.; Cox, D. M.; O'Neill, G. G.; Borge, M. J. G.; Butler, P. A.; Gaffney, L. P.; Greenlees, P. T.; Herzberg, R.-D.; Illana, A.; Joss, D. T.; Konki, J.; Kröll, T.; Ojala, J.; Page, R. D.; Rahkila, P.; Ranttila, K.; Thornhill, J.; Tuunanen, J.; Van Duppen, P.; Warr, N.; Pakarinen, J.

    2018-03-01

    The electron spectrometer, SPEDE, has been developed and will be employed in conjunction with the Miniball spectrometer at the HIE-ISOLDE facility, CERN. SPEDE allows for direct measurement of internal conversion electrons emitted in-flight, without employing magnetic fields to transport or momentum filter the electrons. Together with the Miniball spectrometer, it enables simultaneous observation of γ rays and conversion electrons in Coulomb excitation experiments using radioactive ion beams.

  12. 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)

  13. The VERDI fission fragment spectrometer

    Directory of Open Access Journals (Sweden)

    Frégeau M.O.

    2013-12-01

    Full Text Available The VERDI time-of-flight spectrometer is dedicated to measurements of fission product yields and of prompt neutron emission data. Pre-neutron fission-fragment masses will be determined by the double time-of-flight (TOF technique. For this purpose an excellent time resolution is required. The time of flight of the fragments will be measured by electrostatic mirrors located near the target and the time signal coming from silicon detectors located at 50 cm on both sides of the target. This configuration, where the stop detector will provide us simultaneously with the kinetic energy of the fragment and timing information, significantly limits energy straggling in comparison to legacy experimental setup where a thin foil was usually used as a stop detector. In order to improve timing resolution, neutron transmutation doped silicon will be used. The high resistivity homogeneity of this material should significantly improve resolution in comparison to standard silicon detectors. Post-neutron fission fragment masses are obtained form the time-of-flight and the energy signal in the silicon detector. As an intermediary step a diamond detector will also be used as start detector located very close to the target. Previous tests have shown that poly-crystalline chemical vapour deposition (pCVD diamonds provides a coincidence time resolution of 150 ps not allowing complete separation between very low-energy fission fragments, alpha particles and noise. New results from using artificial single-crystal diamonds (sCVD show similar time resolution as from pCVD diamonds but also sufficiently good energy resolution.

  14. Different spectra with the same neutron source

    International Nuclear Information System (INIS)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A.; Mercado, G. A.

    2010-01-01

    Using as source term the spectrum of a 239 Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239 Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  15. Simulated workplace neutron fields

    International Nuclear Information System (INIS)

    Lacoste, V.; Taylor, G.; Rottger, S.

    2011-01-01

    The use of simulated workplace neutron fields, which aim at replicating radiation fields at practical workplaces, is an alternative solution for the calibration of neutron dosemeters. They offer more appropriate calibration coefficients when the mean fluence-to-dose equivalent conversion coefficients of the simulated and practical fields are comparable. Intensive Monte Carlo modelling work has become quite indispensable for the design and/or the characterization of the produced mixed neutron/photon fields, and the use of Bonner sphere systems and proton recoil spectrometers is also mandatory for a reliable experimental determination of the neutron fluence energy distribution over the whole energy range. The establishment of a calibration capability with a simulated workplace neutron field is not an easy task; to date only few facilities are available as standard calibration fields. (authors)

  16. UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

    CERN Document Server

    Bondarenko, I V; Cimmino, A; Geltenbort, P; Frank, A I; Hoghoj, P; Klein, A G; Masalovich, S V; Nosov, V G

    2000-01-01

    A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress.

  17. UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

    International Nuclear Information System (INIS)

    Bondarenko, I.V.; Balashov, S.N.; Cimmino, A.; Geltenbort, P.; Frank, A.I.; Hoghoj, P.; Klein, A.G.; Masalovich, S.V.; Nosov, V.G.

    2000-01-01

    A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress

  18. Large acceptance spectrometers for invariant mass spectroscopy of exotic nuclei and future developments

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T.; Kondo, Y.

    2016-06-01

    Large acceptance spectrometers at in-flight RI separators have played significant roles in investigating the structure of exotic nuclei. Such spectrometers are in particular useful for probing unbound states of exotic nuclei, using invariant mass spectroscopy with reactions at intermediate and high energies. We discuss here the key characteristic features of such spectrometers, by introducing the recently commissioned SAMURAI facility at the RIBF, RIKEN. We also investigate the issue of cross talk in the detection of multiple neutrons, which has become crucial for exploring further unbound states and nuclei beyond the neutron drip line. Finally we discuss future perspectives for large acceptance spectrometers at the new-generation RI-beam facilities.

  19. Further development of a track detector as the spectrometer of linear energy transfer

    International Nuclear Information System (INIS)

    Spurny, F.; Bednar, J.; Vlcek, B.; Botollier-Depois, J.F.

    1998-01-01

    Track revealing in a track etch detector is a phenomenon related to the linear energy transfer (LET) of the particle registered. The measurements of track parameters permit to determine the LET corresponding to each revealed track, i.e. LET spectrum. We have recently developed a spectrometer of LET based on the chemically etched polyallyldiglycolcarbonate (PADC). In this contribution the results obtained with such spectrometer in some neutron fields are presented, analyzed and discussed. Several radionuclide neutron sources have been used, LET spectrometer has been also exposed in high energy neutron reference fields at CERN and JINR Dubna, and on board aircraft. (author)

  20. The new double energy-velocity spectrometer VERDI

    Science.gov (United States)

    Jansson, Kaj; Frégeau, Marc Olivier; Al-Adili, Ali; Göök, Alf; Gustavsson, Cecilia; Hambsch, Franz-Josef; Oberstedt, Stephan; Pomp, Stephan

    2017-09-01

    VERDI (VElocity foR Direct particle Identification) is a fission-fragment spectrometer recently put into operation at JRC-Geel. It allows measuring the kinetic energy and velocity of both fission fragments simultaneously. The velocity provides information about the pre-neutron mass of each fission fragment when isotropic prompt-neutron emission from the fragments is assumed. The kinetic energy, in combination with the velocity, provides the post-neutron mass. From the difference between pre- and post-neutron masses, the number of neutrons emitted by each fragment can be determined. Multiplicity as a function of fragment mass and total kinetic energy is one important ingredient, essential for understanding the sharing of excitation energy between fission fragments at scission, and may be used to benchmark nuclear de-excitation models. The VERDI spectrometer design is a compromise between geometrical efficiency and mass resolution. The spectrometer consists of an electron detector located close to the target and two arrays of silicon detectors, each located 50 cm away from the target. In the present configuration pre-neutron and post-neutron mass distributions are in good agreement with reference data were obtained. Our latest measurements performed with spontaneously fissioning 252Cf is presented along with the developed calibration procedure to obtain pulse height defect and plasma delay time corrections.

  1. Current status of neutron scattering in Thailand

    International Nuclear Information System (INIS)

    Ampornrat, Pantip

    1999-01-01

    Thailand's neutron spectrometer has been installed soon after the startup of the reactor. The neutron scattering experiments have been done continuously, although there were some problems involving the neutron intensity and instruments. Development program has been planned for better experimental result. This paper reports the past and present status of neutron scattering equipment and experiments in Thailand. In addition, installation of a HRPD (High Resolution Powder Diffraction) system is included within the scope of the Ongkharak Nuclear Research Center project. (author)

  2. Mass spectrometers in medicine

    International Nuclear Information System (INIS)

    Bushman, J.A.

    1975-01-01

    This paper describes how the mass spectrometer enables true lung function, namely the exchange of gases between the environment and the organism, to be measured. This has greatly improved the understanding of respiratory disease and the latest generation of respiratory mass spectrometers will do much to increase the application of the technique. (author)

  3. The Omicron Spectrometer

    CERN Document Server

    Allardyce, B W

    1976-01-01

    It is intended to build a spectrometer with a large solid angle and a large momentum acceptance at the reconstructed synchrocyclotron at CERN. This spectrometer will have an energy resolution of about 1 MeV for particles with momenta up to about 400 MeV/c.

  4. Applications of Bonner sphere detectors in neutron field dosimetry

    International Nuclear Information System (INIS)

    Awschalom, M.; Sanna, R.S.

    1983-09-01

    The theory of neutron moderation and spectroscopy are briefly reviewed, and moderators that are useful for Bonner sphere spectrometers are discussed. The choice of the neutron detector for a Bonner sphere spectrometer is examined. Spectral deconvolution methods are briefly reviewed, including derivative, parametric, quadrature, and Monte Carlo methods. Calibration is then discussed

  5. A Novel Detector for High Neutron Flux Measurements

    International Nuclear Information System (INIS)

    Singo, T. D.; Wyngaardt, S. M.; Papka, P.; Dobson, R. T.

    2010-01-01

    Measuring alpha particles from a neutron induced break-up reaction with a mass spectrometer can be an excellent tool for detecting neutrons in a high neutron flux environment. Break-up reactions of 6 Li and 12 C can be used in the detection of slow and fast neutrons, respectively. A high neutron flux detection system that integrates the neutron energy sensitive material and helium mass spectrometer has been developed. The description of the detector configuration is given and it is soon to be tested at iThemba LABS, South Africa.

  6. Measurement and analysis of leakage neutron energy spectra around the Kinki University Reactor, UTR-KINKI

    CERN Document Server

    Ogawa, Y; Sagawa, H; Tsujimoto, T

    2002-01-01

    The highly sensitive cylindrical multi-moderator type neutron spectrometer was constructed for measurement of low level environmental neutrons. This neutron spectrometer was applied for the determination of leakage neutron energy spectra around the Kinki University Reactor. The analysis of the leakage neutron energy spectra was performed by MCNP Monte Carlo code. From the obtained results, the agreement between the MCNP predictions and the experimentally determined values is fairly good, which indicates the MCNP model is correctly simulating the UTR-KINKI.

  7. Opening the terahertz window on the OSIRIS spectrometer

    Directory of Open Access Journals (Sweden)

    Demmel F.

    2015-01-01

    Full Text Available A cooled and mechanically retractable beryllium filter has been installed and commissioned on the low-energy OSIRIS spectrometer at ISIS. This instrument development extends the energy-transfer range of the spectrometer up to ca. 20 meV (∼ 5 THz, leading to an excellent resolution at THz frequencies and substantial gains in detected flux relative to existing capabilities on the neighbouring IRIS spectrometer. Herein, we provide a concise account of this new capability for high-resolution neutron spectroscopy in the THz domain, as well as outline a number of ongoing and potential scientific opportunities in condensed-matter physics, chemistry, and materials science.

  8. PNG-300 a nanosecond pulsed neutron generator

    International Nuclear Information System (INIS)

    Sztaricskai, T.; Vasvary, L.; Petoe, G.C.; Devkin, B.V.

    1985-01-01

    The design and operation of a nanosecond-pulse neutron generator is reported. It was constructed for the measurement of prompt neutron and gamma radiation in experimental studies of fast neutron reactions by time of flight techniques. The acceleration voltage is 300 kV and the total resolution of the generator-neutron spectrometer system is 2 ns. The ion-optical system, the vacuum system and the control of the neutron generator is described in detail. The equipment was used for prompt neutron and gamma radiation induced in construction materials. (R.P.)

  9. VESUVIO--the double difference inverse geometry spectrometer at ISIS

    International Nuclear Information System (INIS)

    Mayers, J.; Tomkinson, J.; Abdul-Redah, T.; Stirling, W.G.; Andreani, C.; Senesi, R.; Nardone, M.; Colognesi, D.; Degiorgi, E.

    2004-01-01

    The VESUVIO spectrometer at the ISIS pulsed neutron source performs inelastic neutron scattering at high-energy and wave vector transfers, employing gold and uranium resonant foils. A factor of two improvement in the instrumental resolution has been achieved by making use of the double filter difference method. Experimental results are presented for measurements on polycrystalline Pb, which indicate that accurate measurements of single-particle momentum distribution n(p) in quantum fluids are now possible at eV energy transfers

  10. VESUVIO--the double difference inverse geometry spectrometer at ISIS

    Energy Technology Data Exchange (ETDEWEB)

    Mayers, J.; Tomkinson, J.; Abdul-Redah, T.; Stirling, W.G.; Andreani, C.; Senesi, R.; Nardone, M.; Colognesi, D.; Degiorgi, E

    2004-07-15

    The VESUVIO spectrometer at the ISIS pulsed neutron source performs inelastic neutron scattering at high-energy and wave vector transfers, employing gold and uranium resonant foils. A factor of two improvement in the instrumental resolution has been achieved by making use of the double filter difference method. Experimental results are presented for measurements on polycrystalline Pb, which indicate that accurate measurements of single-particle momentum distribution n(p) in quantum fluids are now possible at eV energy transfers.

  11. VESUVIO-the double difference inverse geometry spectrometer at ISIS

    Science.gov (United States)

    Mayers, J.; Tomkinson, J.; Abdul-Redah, T.; Stirling, W. G.; Andreani, C.; Senesi, R.; Nardone, M.; Colognesi, D.; Degiorgi, E.

    2004-07-01

    The VESUVIO spectrometer at the ISIS pulsed neutron source performs inelastic neutron scattering at high-energy and wave vector transfers, employing gold and uranium resonant foils. A factor of two improvement in the instrumental resolution has been achieved by making use of the double filter difference method. Experimental results are presented for measurements on polycrystalline Pb, which indicate that accurate measurements of single-particle momentum distribution n(p) in quantum fluids are now possible at eV energy transfers.

  12. The SAGE spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Pakarinen, J.; Papadakis, P. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Sorri, J.; Greenlees, P.T.; Jones, P.; Julin, R.; Konki, J.; Rahkila, P.; Sandzelius, M. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Cresswell, J.R.; Mistry, A.; Page, R.D.; Parr, E.; Sampson, J.; Seddon, D.A.; Thornhill, J.; Wells, D. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Coleman-Smith, P.J.; Lazarus, I.H.; Letts, S.C.; Pucknell, V.F.E.; Simpson, J. [STFC Daresbury Laboratory, Warrington (United Kingdom)

    2014-03-15

    The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of γ-rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and γ-rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyvaeskylae and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method. (orig.)

  13. The SAGE spectrometer

    International Nuclear Information System (INIS)

    Pakarinen, J.; Papadakis, P.; Sorri, J.; Greenlees, P.T.; Jones, P.; Julin, R.; Konki, J.; Rahkila, P.; Sandzelius, M.; Herzberg, R.D.; Butler, P.A.; Cox, D.M.; Cresswell, J.R.; Mistry, A.; Page, R.D.; Parr, E.; Sampson, J.; Seddon, D.A.; Thornhill, J.; Wells, D.; Coleman-Smith, P.J.; Lazarus, I.H.; Letts, S.C.; Pucknell, V.F.E.; Simpson, J.

    2014-01-01

    The SAGE spectrometer has been constructed for in-beam nuclear structure studies. SAGE combines a Ge-detector array and an electron spectrometer for detection of γ-rays and internal conversion electrons, respectively, and allows simultaneous observation of both electrons and γ-rays emitted from excited nuclei. SAGE is set up in the Accelerator Laboratory of the University of Jyvaeskylae and works in conjunction with the RITU gas-filled recoil separator and the GREAT focal-plane spectrometer allowing the use of the recoil-decay tagging method. (orig.)

  14. The MEG positron spectrometer

    International Nuclear Information System (INIS)

    Nishiguchi, Hajime

    2007-01-01

    We have been developing an innovative spectrometer for the MEG experiment at the Paul Scherrer Institute (PSI) in Switzerland. This experiment searches for a lepton flavour violating decay μ + →e + γ with a sensitivity of 10 -13 in order to explore the region predicted by supersymmetric extensions of the standard model. The MEG positron spectrometer consists of a specially designed superconducting solenoidal magnet with a highly graded field, an ultimate low-mass drift chamber system, and a precise time measuring counter system. This innovative positron spectrometer is described here focusing on the drift chamber system

  15. Experimental technique of small angle neutron scattering

    International Nuclear Information System (INIS)

    Xia Qingzhong; Chen Bo

    2006-03-01

    The main parts of Small Angle Neutron Scattering (SANS) spectrometer, and their function and different parameters are introduced from experimental aspect. Detailed information is also introduced for SANS spectrometer 'Membrana-2'. Based on practical experiments, the fundamental requirements and working condition for SANS experiments, including sample preparation, detector calibration, standard sample selection and data preliminary process are described. (authors)

  16. Condensed matter and materials research using neutron diffraction and spectroscopy: reactor and pulsed neutron sources

    International Nuclear Information System (INIS)

    Bisanti, Paola; Lovesey, S.W.

    1987-05-01

    The paper provides a short, and partial view of the neutron scattering technique applied to condensed matter and materials research. Reactor and accelerator-based neutron spectrometers are discussed, together with examples of research projects that illustrate the puissance and modern applications of neutron scattering. Some examples are chosen to show the range of facilities available at the medium flux reactor operated by Casaccia ENEA, Roma and the advanced, pulsed spallation neutron source at the Rutherford Appleton Laboratory, Oxfordshire. (author)

  17. Neutron resonance spins of 159Tb from experiments with polarized neutrons and polarized nuclei

    International Nuclear Information System (INIS)

    Alfimenkov, V.P.; Ivanenko, A.I.; Lason', L.; Mareev, Yu.D.; Ovchinnikov, O.N.; Pikel'ner, L.B.; Sharapov, Eh.I.

    1976-01-01

    Spins of 27 neutron resonances of 159 Tb with energies up to 114 eV have been measured using polarized neutrons and nuclei beams in the modernized time-of-flight spectrometer of the IBR-30 pulse reator. The direct measurements of the terbium resonances spins performed using polarized neutrons reaffirm the conclusion that there are no unstationary effects in the behaviour of 159 Tb neutron resonances in the energy range

  18. Digital positron annihilation spectrometer

    International Nuclear Information System (INIS)

    Cheng Bin; Weng Huimin; Han Rongdian; Ye Bangjiao

    2010-01-01

    With the high speed development of digital signal process, the technique of the digitization and processing of signals was applied in the domain of a broad class of nuclear technique. The development of digital positron lifetime spectrometer (DPLS) is more promising than the conventional positron lifetime spectrometer equipped with nuclear instrument modules. And digital lifetime spectrometer has many advantages, such as low noise, long term stability, flexible online or offline digital processing, simple setup, low expense, easy to setting, and more physical information. Digital constant fraction discrimination is for timing. And a new method of optimizing energy windows setting for digital positron lifetime spectrometer is also developed employing the simulated annealing for the convenient use. The time resolution is 220ps and the count rate is 200cps. (authors)

  19. Micro Plasma Spectrometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this IRAD project is to develop a preliminary design elements of miniature electron and ion plasma spectrometers and supporting electronics, focusing...

  20. Fourier Transform Spectrometer System

    Science.gov (United States)

    Campbell, Joel F. (Inventor)

    2014-01-01

    A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.