WorldWideScience

Sample records for ake-02r system neutron

  1. Pulsed neutron porosity logging system

    International Nuclear Information System (INIS)

    An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations and, during the bursts, the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

  2. Neutron imaging system for neutron tomography, radiography, and beam diagnostics

    International Nuclear Information System (INIS)

    A neutron imaging system (NIS) has been recently installed at the University of Texas TRIGA reactor facility. The imaging system establishes new capabilities for beam diagnostics at the Texas Cold Neutron Source (TCNS) for real-time neutron radiography (RTNR) and for neutron computed tomography (NCT) research. The NIS will also be used for other research projects. The system consists of two subsystems as follows: (1) Thomson 9-in. neutron image intensifier (NII) tube sensitive to cold, thermal, and epithermal neutrons, (2) image-processing unit consisting of vidicon camera, two high-resolution monitors, image enhancement and measurement processor, and video printer. The NIS is installed at the cold neutron beam of the TCNS for testing and cold neutron beam diagnostics

  3. Complementary neutron flux monitoring system

    International Nuclear Information System (INIS)

    The present work is an example for that, how with modern technical instruments it is possible to compensate disadvantage and to increase technical resources of the old systems, without a change of given system totally with new one. The system detail design and implementation was possible mostly, due to the international conferences and courses organized by IAEA and technical information provided by the agency. The system acts as a complementary to the existing systems for the reactor core neutron flux monitoring AKNP. The new system extends the measurement range of the original AKNP system approximately by two decades. It allows neutron flux to be monitored during refuelling. The system is permitted for use by Bulgarian Nuclear Safety Authority - CUAEPP. The system also calculates the reactivity and thus allows the operator to monitor the criticality condition very precisely. The system calculates also the period of the reactor and has adjustable setpoints at two levels for alarm and pre-alarm, both for counting rate and period. The system sends the analog signals for the counting rate and for the period as well as digital signals for the alarm and pre-alarm to the refueling machine cabin for on-line control. It also produces sound and blinks (LEDs) if any setpoint is reached. It should be mentioned that the refueling machine panel do not need additional power supply and thus high reliability is achieved. The system automatically stores the data for neutron flux, period, reactivity, alarm and prealarm state and value, reactor kinetic parameters(β,λ and source) on hard disk. The stored data can be reviewed very easy and printed. Depending on the hard disk capacity the storage period can be longer than a year. The old system for neutron flux monitoring during refuelling, which operated with 3 removable neutron fission chambers KNT-54 located next to the reactor core is now obsolete and is decommissioned. This have the significant impact on personnel dose

  4. General Design for CARR Neutron Guide System

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A neutron guide system has been designed and partly installed at the China Advanced Research Reactor (CARR) to transport cold neutrons from the cold neutron source (CNS) to several instruments,which are situated in a separate guide hall of 30 m×60 m.

  5. Improvement of Delayed Neutron Counting System

    Institute of Scientific and Technical Information of China (English)

    YUAN; Guo-jun; XIAO; Cai-jin; YANG; Wei; ZHANG; Gui-ying; JIN; Xiang-chun; WANG; Ping-sheng; NI; Bang-fa

    2012-01-01

    <正>A new delayed neutron counting system, which is good at qualitative and quantitative analysis of fissionable nuclide mixture, will be established at China Advanced Research Reactor (CARR). We use 3 He proportional counters to count the delayed neutrons after the samples irradiated by reactor neutrons, including U3O8-stantard, uranium ore and enriched uranium. Then, the counting efficiency and limit of this system were calculated.

  6. Neutron scanning system for nondestructive testing

    International Nuclear Information System (INIS)

    Presented are the methods of nondestructive testing, based on neutron passing, outlet from the reactor, through the samples. Considered are possibilities of the neutron-spectrometric method of nondestructive sample analysis. Given is a description of half-automatic neutron scanning system, presupposed for investigation of nonirradiated, as well as irradiated samples. Described are the assemblies of the scanning device, mechanical relative aperture selector and crystalline monochromator for the purposes of nondestructive testing by the neutron-spectrometric method within 0.01-50 eV neutron energy range. The scanning device makes it possible to investigate a sample 1200 mm long and up to 15 mm in diameter with longitudinal transmission step of 0.5 mm and 0.1 mm accuracy of the transverse device. The equipment neutron spectra, measured by division chamber on the mechanical selector and the scaning results on the crystalline monochromator are given for illustrating the device operation

  7. Characterization of a neutron-beta counting system with beta-delayed neutron emitters

    OpenAIRE

    Agramunt Ros, Jorge; Taín, J. L.; Gómez Hornillos, María Belén; Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere; Pretel Sánchez, Carme; Riego Pérez, Albert; Tarifeño Saldivia, Ariel Esteban

    2016-01-01

    A new detection system for the measurement of beta-delayed neutron emission probabilities has been characterized using fission products with well known ß-delayed neutron emission properties. The setup consists of BELEN-20, a 4p neutron counter with twenty 3He proportional tubes arranged inside a large polyethylene neutron moderator, a thin Si detector for ß counting and a self-triggering digital data acquisition system. The use of delayed-neutron precursors with different neutron emission win...

  8. Manually controlled neutron-activation system

    Science.gov (United States)

    Johns, R. A.; Carothers, G. A.

    1982-01-01

    A manually controlled neutron activation system, the Manual Reactor Activation System, was designed and built and has been operating at one of the Savannah River Plant's production reactors. With this system, samples can be irradiated for up to 24 hours and pneumatically transferred to a shielded repository for decay until their activity is low enough for them to be handled at a radiobench. The Manual Reactor Activation System was built to provide neutron activation of solid waste forms for the Alternative Waste Forms Leach Testing Program. Neutron activation of the bulk sample prior to leaching permits sensitive multielement radiometric analyses of the leachates.

  9. A digital control system for neutron spectrometers

    DEFF Research Database (Denmark)

    Hansen, Knud Bent; Skaarup, Per

    1968-01-01

    A description is given of the principles of a digital system used to control neutron spectrometers. The system is composed of independent functional units with the control programme stored on punched paper tape or in a computer.......A description is given of the principles of a digital system used to control neutron spectrometers. The system is composed of independent functional units with the control programme stored on punched paper tape or in a computer....

  10. Development of the environmental neutron detection system

    CERN Document Server

    Kume, K

    2003-01-01

    Environmental neutron detection system is proposed. The main goal of this system was set to detect fast and thermal neutrons with the identical detector setup without degraders. A detector setup for the system with a sup 1 sup 0 B doped liquid scintillator, which had been optimized for thermal neutron counting in last year, was developed first. For optimization of for fast neutron counting, density of sup 1 sup 0 B and the size of the detector were fixed by measurement of fast neutrons, with help of the Monte Carlo calculation. In the meantime, possibility of the use of inorganic scintillators in neutron counting were verified, to solve the problem occurring at the long term use of the organic liquid scintillators. The detectors checked were LSO, BaF sub 2 , BGO and GSO. LSO and BaF sub 2 have much more difficulties in neutron counting such as background counting rates and BGO has some unclear signals at neutron measurements. GSO was shown to be the most probable candidate among them at the measurement of neu...

  11. Accelerator system for neutron radiography

    International Nuclear Information System (INIS)

    The field of x-ray radiography is well established for doing non-destructive evaluation of a vast array of components, assemblies, and objects. While x-rays excel in many radiography applications, their effectiveness diminishes rapidly if the objects of interest are surrounded by thick, high-density materials that strongly attenuate photons. Due to the differences in interaction mechanisms, neutron radiography is highly effective in imaging details inside such objects. To obtain a high intensity neutron source suitable for neutron imaging a 9-MeV linear accelerator is being evaluated for putting a deuteron beam into a high-pressure deuterium gas cell. As a windowless aperture is needed to transport the beam into the gas cell, a low-emittance is needed to minimize losses along the high-energy beam transport (HEBT) and the end station. A description of the HEBT, the transport optics into the gas cell, and the requirements for the linac will be presented

  12. DIANE: Advanced system for mobile neutron radiology

    Science.gov (United States)

    Dance, W. E.; Huriet, J. R.; Cluzeau, S.; Mast, H.-U.; Albisu, F.

    1989-04-01

    Development of a new neutron radiology system, DIANE, is underway which will provide a ten-fold improvement in image-acquisition speed over presently operating mobile systems, insuring greater inspection throughput for production applications. Based on a 10 12 n/s sealed-tube (D-T) neutron generator under development by Sodern, on LTV's neutron moderator/collimator and electronic imaging systems and on robotic and safety systems being developed by IABG and Sener, the DIANE concept is that of a complete facility for on-site neutron radiography or radioscopy. The LTV components, which provide film or electronic imaging, including digital processing of 12-bit images, have been demonstrated in three basic systems now operating with Kaman A-711 neutron generators, including one operating in IABG's facilities. Sodern has fabricated a prototype neutron generator tube, the TN 46, for emission of 10 11 n/s over 1000 to 1500 hours, at 250 kV and 2 mA in the ion beam.

  13. A system for fast neutron radiography

    International Nuclear Information System (INIS)

    A system has been designed and a neutron generator installed to perform fast neutron radiography. With this system, objects as small as a coin and as large as a 19 liter container have been radiographed. The neutron source is an MF Physics A-711 neutron generator which produces 3 x 10[sup 10] neutrons/second with an average energy of 14. 5 MeV. The radiography system uses x-ray scintillation screens and film in commercially available light-tight cassettes. The cassettes have been modified to include a thin sheet of plastic to produce protons from the neutron beam through elastic scattering from hydrogen and other low Z materials in the plastic. For film densities from 1.8 to 3.0, exposures range from 1.9 x 10[sup 7] n/cm[sup 2] to 3.8 x 10[sup 8] n/cm[sup 2] depending on the type of screen and film. The optimum source-to-film distance was found to be 150 cm. At this distance, the geometric unsharpness was determined to be approximately 2.2-2.3 mm and the smallest hole that could be resolved in a 1.25 cm thick sample had a diameter of 0.079 cm

  14. Design of a system for neutrons dosimetry

    International Nuclear Information System (INIS)

    At the present time diverse systems of detection of neutrons exist, as proportional counters based on BF3, He3 and spectrometers of Bonner spheres. However, the cost and the complexity of the implementation of these systems put them far from the reach for dosimetric purposes. For these reasons a system of neutrons detection composed by a medium paraffin moderator that forms a 4π (spheres) arrangement and of several couples of thermoluminescent dosimeters TLD 600/TLD 700. The response of the system presents a minor repeatability to 5% in several assays when being irradiated with a 239PuBe source and a deviation of 13.8% in the Tl readings of four different spheres. The calibration factor of the system with regard to the neutrons source which was of 56.2 p Sv/nc also was calculated. These detectors will be used as passive monitors of photoneutrons in a radiotherapy room with lineal accelerator of high energy. (Author)

  15. Spallation neutron source RF cavity bias system

    International Nuclear Information System (INIS)

    The Spallation Neutron Source r.f. cavity bias system is described under the topic headings: bias system, r.f. cavity, cables, d.c. bias power supply, transistor regulator and control system. Calculation of 4 core 300 mm solid aluminium cable inductance, coaxial shunt frequency response and transistor regulator computed frequency response, are discussed in appendices 1-3. (U.K.)

  16. The National Ignition Facility Neutron Imaging System

    International Nuclear Information System (INIS)

    The National Ignition Facility (NIF) is scheduled to begin deuterium-tritium (DT) shots possibly in the next several years. One of the important diagnostics in understanding capsule behavior and to guide changes in Hohlraum illumination, capsule design, and geometry will be neutron imaging of both the primary 14 MeV neutrons and the lower-energy downscattered neutrons in the 6-13 MeV range. The neutron imaging system (NIS) described here, which we are currently building for use on NIF, uses a precisely aligned set of apertures near the target to form the neutron images on a segmented scintillator. The images are recorded on a gated, intensified charge coupled device. Although the aperture set may be as close as 20 cm to the target, the imaging camera system will be located at a distance of 28 m from the target. At 28 m the camera system is outside the NIF building. Because of the distance and shielding, the imager will be able to obtain images with little background noise. The imager will be capable of imaging downscattered neutrons from failed capsules with yields Yn>1014 neutrons. The shielding will also permit the NIS to function at neutron yields >1018, which is in contrast to most other diagnostics that may not work at high neutron yields. The following describes the current NIF NIS design and compares the predicted performance with the NIF specifications that must be satisfied to generate images that can be interpreted to understand results of a particular shot. The current design, including the aperture, scintillator, camera system, and reconstruction methods, is briefly described. System modeling of the existing Omega NIS and comparison with the Omega data that guided the NIF design based on our Omega results is described. We will show NIS model calculations of the expected NIF images based on component evaluations at Omega. We will also compare the calculated NIF input images with those unfolded from the NIS images generated from our NIS numerical modeling

  17. Neutron Scattering Investigations of Correlated Electron Systems and Neutron Instrumentation

    DEFF Research Database (Denmark)

    Holm, Sonja Lindahl

    are a unique probe for studying the atomic and molecular structure and dynamics of materials. Even though neutrons are very expensive to produce, the advantages neutrons provide overshadow the price. As neutrons interact weakly with materials compared to many other probes, e.g. electrons or photons...... section varies through the periodic table in a seemingly random fashion. Neutron scattering offers a unique possibility to study light elements that have relatively high cross sections. The first main topic is on neutron instrumentation for the European Spallation Source (ESS). ESS is currently under...... in the appended published paper. A short summary is given in the main text of the thesis. HEIMDAL will be a multi length scale neutron scattering instrument for the study of structures covering almost nine orders of magnitude from 0.01 nm to 50 mm. The instrument features a variable resolution thermal neutron...

  18. Neutronic parameters characterizing accelerator driven system (ADS)

    International Nuclear Information System (INIS)

    An hybrid system is a reactor where an external source of spallation neutrons is supplied to a subcritical multiplying medium. The neutronic parameters characterising such a system include, in addition to the multiplication factor which measures the sub-criticality level, another physics parameter measuring the 'importance' of the external source. The aim of this thesis is, on the one hand, to investigate basic neutronic phenomena taking place in fast sub- critical media in either steady-state or transient operation, and, on the other hand, to assess the performance of the ERANOS neutronic code package applied to the analysis of such systems. To this aim, the first part of the work is focused on the MUSE program and in particular the MUSE3 experiment, which consists of different sub-critical configurations driven by a 14-MeV neutron source. This study has been pursued in two directions : the first one was the interpretation of the calculation-experiment (C-E) discrepancies which lead to the development of original calculation methods for sensitivity studies ; the second one was the experimental analysis which allowed an extensive neutronic characterization of the sub-critical system. A correlation between the external source importance and some directly measurable parameters (i.e. fission rate) was derived. The second part of the thesis addresses representativity issues between an experimental facility and an actual power reactor. Important conclusions have been drawn with regard to the operation of an ADS. Finally, representativity studies lead to the recommendation that a demonstration reactor should be built before an industrial plant is constructed. (author)

  19. Earth formation pulsed neutron porosity logging system utilizing epithermal neutron and inelastic scattering gamma ray detectors

    International Nuclear Information System (INIS)

    An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector and an inelastic scattering gamma ray detector is moved through a borehole. The detection of inelastic gamma rays provides a measure of the fast neutron population in the vicinity of the detector. repetitive bursts of neutrons irradiate the earth formation and, during the busts, inelastic gamma rays representative of the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. the fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

  20. Performances of some mobile neutron radiography systems

    International Nuclear Information System (INIS)

    Present paper describes shortly three different mobile neutron radiography systems in term of characteristic, performances, flexibility, and their main applications for non destructive testing of materials, devices and structures. Examples of applications in different fields, with particular attention to aeronautics (early corrosion detection, turbine blades quality control inspection) and pyrotechnic devices / specific parts inspection, are presented.(author)

  1. A microprocessor system for a neutron chopper

    International Nuclear Information System (INIS)

    An electronic system with the use of a microprocessor for operation automation, stabilization of speed and phase in the IBR-2 neutron chopper sis described. The root mean square deviation of chopper phase for 5 Hz frequency of reactor operation does not exceed 50 μs

  2. Systems and methods for detecting neutrons

    Science.gov (United States)

    Bross, Alan D.; Mellott, Kerry L.; Pla-Dalmau, Anna

    2005-08-09

    Systems and methods for detecting neutrons. One or more neutron-sensitive scintillators can be configured from a plurality of nano-sized particles, dopants and an extruded plastic material, such as polystyrene. The nano-sized particles can be compounded into the extruded plastic material with at least one dopant that permits the plastic material to scintillate. One or more plastic light collectors can be associated with a neutron-sensitive scintillator, such that the plastic light collector includes a central hole thereof. A wavelength-shifting fiber can then be located within the hole. The wavelength shifting (WLS) fiber absorbs scintillation light having a wavelength thereof and re-emits the light at a longer wavelength.

  3. Development of fast neutron radiography system based on portable neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Chia Jia, E-mail: gei-i-kani@hotmail.com; Nilsuwankosit, Sunchai, E-mail: sunchai.n@chula.ac.th [Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Rd., Patumwan, Bangkok, THAILAND 10330 (Thailand)

    2016-01-22

    Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. The raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons.

  4. Development of fast neutron radiography system based on portable neutron generator

    Science.gov (United States)

    Yi, Chia Jia; Nilsuwankosit, Sunchai

    2016-01-01

    Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. The raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons.

  5. Development of fast neutron radiography system based on portable neutron generator

    International Nuclear Information System (INIS)

    Due to the high installation cost, the safety concern and the immobility of the research reactors, the neutron radiography system based on portable neutron generator is proposed. Since the neutrons generated from a portable neutron generator are mostly the fast neutrons, the system is emphasized on using the fast neutrons for the purpose of conducting the radiography. In order to suppress the influence of X-ray produced by the neutron generator, a combination of a shielding material sandwiched between two identical imaging plates is used. A binary XOR operation is then applied for combining the information from the imaging plates. The raw images obtained confirm that the X-ray really has a large effect and that XOR operation can help enhance the effect of the neutrons

  6. The neutron imaging system fielded at the National Ignition Facility

    International Nuclear Information System (INIS)

    We have fielded a neutron imaging system at the National Ignition Facility to collect images of fusion neutrons produced in the implosion of inertial confinement fusion experiments and scattered neutrons from (n, n') reactions of the source neutrons in the surrounding dense material. A description of the neutron imaging system is presented, including the pinhole array aperture, the line-of-sight collimation, the scintillator-based detection system and the alignment systems and methods. Discussion of the alignment and resolution of the system is presented. We also discuss future improvements to the system hardware. (authors)

  7. The Neutron Imaging System Fielded at the National Ignition Facility

    International Nuclear Information System (INIS)

    We have fielded a neutron imaging system at the National Ignition Facility to collect images of fusion neutrons produced in the implosion of inertial confinement fusion experiments and scattered neutrons from (n, n') reactions of the source neutrons in the surrounding dense material. A description of the neutron imaging system will be presented, including the pinhole array aperture, the line-of-sight collimation, the scintillator-based detection system and the alignment systems and methods. Discussion of the alignment and resolution of the system will be presented. We will also discuss future improvements to the system hardware.

  8. The neutron imaging system fielded at the National Ignition Facility

    Directory of Open Access Journals (Sweden)

    Fittinghoff D.N.

    2013-11-01

    Full Text Available We have fielded a neutron imaging system at the National Ignition Facility to collect images of fusion neutrons produced in the implosion of inertial confinement fusion experiments and scattered neutrons from (n, n′ reactions of the source neutrons in the surrounding dense material. A description of the neutron imaging system is presented, including the pinhole array aperture, the line-of-sight collimation, the scintillator-based detection system and the alignment systems and methods. Discussion of the alignment and resolution of the system is presented. We also discuss future improvements to the system hardware.

  9. Development of the environmental neutron detection system

    CERN Document Server

    Kume, K

    2002-01-01

    Environmental neutron detection system was proposed and developed. The main goal of this system was set to detect fast and thermal neutrons with the identical detectors setup without degraders. This system consists of a sup 1 sup 0 B doped liquid scintillator for n detection and CsI scintillators for simultaneous gamma emission from sup 1 sup 0 B doped in the liquid scintillator after the n capture reaction. The first setup was optimized for the thermal n detection, while the second setup was for the fast n detection. It was shown that the thermal n flux was obtained in the first setup by using the method of the gamma coincidence method with the help of the Monte Carlo calculation. The second setup was designed to improve the detection efficiency for the fast n, and was shown qualitatively that both the pulse shape discrimination and the coincidence methods are efficient. There will be more improvements, particularly for the quantitative discussion.

  10. Development of New Drummed Nuclear Waste Neutron Counting System

    Institute of Scientific and Technical Information of China (English)

    ZHU; Li-qun; XU; Xiao-ming; BAI; Lei; LI; Xin-jun; GU; Shao-gang; HE; Li-xia; WANG; Mian

    2012-01-01

    <正>The development of a new neutron counting system (Fig. 1) for 200 L drummed radioactive waste measurement has been accomplished in this year. This waste neutron counting system is mainly used for solid radioactive waste classification. It is based on the passive neutron counting technique. The amount of radionuclide contained in the waste is

  11. Theory of multiple neutron scattering in multilayer systems

    International Nuclear Information System (INIS)

    Strict dynamic theory is developed for neutron scattering by the multilayer systems (MS) formed by films of different material. The neutron conduction bands with N-1 levels are shown to exist in MS of N bilayers. In the absence of absorption the system of N bilayers is completely transparent for neutrons if the normal component of their kinetic energy equals the energy of a conduction band level. The scattering of neutrons in MS with magnetic films and polarized nuclei is considered

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-01-01

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

  13. Real time neutron image processing system in NRF

    International Nuclear Information System (INIS)

    The neutron radiography facility was installed at the neutron radiography beam tube of the HANARO research reactor. The NRF is used for the nondestructive test to inspect and evaluate the material defect and homogeneity by detecting the transmitted neutron image in the nuclear as well as non-nuclear industry. To analyze the dynamical neutron image effectively and efficiently, the real-time image processing system was developed in background subtraction, normalization, geometry correction and beam uniformity, contrast control, filtering. The image quality test and dimension measurements were performed for the neutron beam purity and sensitivity indication. The NRF beam condition represents the highest beam quality for neutron radiography.

  14. System design considerations for fast-neutron interrogation systems

    Energy Technology Data Exchange (ETDEWEB)

    Micklich, B.J.; Curry, B.P.; Fink, C.L.; Smith, D.L.; Yule, T.J.

    1993-10-01

    Nonintrusive interrogation techniques that employ fast neutrons are of interest because of their sensitivity to light elements such as carbon, nitrogen, and oxygen. The primary requirement of a fast-neutron inspection system is to determine the value of atomic densities, or their ratios, over a volumetric grid superimposed on the object being interrogated. There are a wide variety of fast-neutron techniques that can provide this information. The differences between the various nuclear systems can be considered in light of the trade-offs relative to the performance requirements for each system`s components. Given a set of performance criteria, the operational requirements of the proposed nuclear systems may also differ. For instance, resolution standards will drive scanning times and tomographic requirements, both of which vary for the different approaches. We are modelling a number of the fast-neutron interrogation techniques currently under consideration, to include Fast Neutron Transmission Spectroscopy (FNTS), Pulsed Fast Neutron Analysis (PFNA), and its variant, 14-MeV Associated Particle Imaging (API). The goals of this effort are to determine the component requirements for each technique, identify trade-offs that system performance standards impose upon those component requirements, and assess the relative advantages and disadvantages of the different approaches. In determining the component requirements, we will consider how they are driven by system performance standards, such as image resolution, scanning time, and statistical uncertainty. In considering the trade-offs between system components, we concentrate primarily on those which are common to all approaches, for example: source characteristics versus detector array requirements. We will then use the analysis to propose some figures-of-merit that enable performance comparisons between the various fast-neutron systems under consideration. The status of this ongoing effort is presented.

  15. MPACT Fast Neutron Multiplicity System Design Concepts

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; S. A. Pozzi; J. L. Dolan; M. T. Kinlaw; A. C. Kaplan; M. Flaska; A. Enqvist; J. T. Johnsom; S. M. Watson

    2012-10-01

    This report documents work performed by Idaho National Laboratory and the University of Michigan in fiscal year (FY) 2012 to examine design parameters related to the use of fast-neutron multiplicity counting for assaying plutonium for materials protection, accountancy, and control purposes. This project seeks to develop a new type of neutron-measurement-based plutonium assay instrument suited for assaying advanced fuel cycle materials. Some current-concept advanced fuels contain high concentrations of plutonium; some of these concept fuels also contain other fissionable actinides besides plutonium. Because of these attributes the neutron emission rates of these new fuels may be much higher, and more difficult to interpret, than measurements made of plutonium-only materials. Fast neutron multiplicity analysis is one approach for assaying these advanced nuclear fuels. Studies have been performed to assess the conceptual performance capabilities of a fast-neutron multiplicity counter for assaying plutonium. Comparisons have been made to evaluate the potential improvements and benefits of fast-neutron multiplicity analyses versus traditional thermal-neutron counting systems. Fast-neutron instrumentation, using for example an array of liquid scintillators such as EJ-309, have the potential to either a) significantly reduce assay measurement times versus traditional approaches, for comparable measurement precision values, b) significantly improve assay precision values, for measurement durations comparable to current-generation technology, or c) moderating improve both measurement precision and measurement durations versus current-generation technology. Using the MCNPX-PoliMi Monte Carlo simulation code, studies have been performed to assess the doubles-detection efficiency for a variety of counter layouts of cylindrical liquid scintillator detector cells over one, two, and three rows. Ignoring other considerations, the best detector design is the one with the most

  16. Design of Pre-collimator System for Neutronics Benchmark Experiment

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In order to carry out evaluation of neutron nuclear data, in the last "Five-Year" period, China Institute of Atomic Energy has developed a set of neutron nuclear data benchmarking test system, and used the time-of-flight technique to measure the neutron

  17. Portable system for periodical verification of area monitors for neutrons

    International Nuclear Information System (INIS)

    The Neutrons Laboratory develops a project viewing the construction of a portable test system for verification of functioning conditions of neutron area monitors. This device will allow to the users the verification of the calibration maintenance of his instruments at the use installations, avoiding the use of an inadequate equipment related to his answer to the neutron beam response

  18. The Spallation Neutron Source accelerator system design

    Science.gov (United States)

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

    2014-11-01

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

  19. The Spallation Neutron Source accelerator system design

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-01

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

  20. System Engineering Status and Design Characteristics of Cold Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ki; Jung, H. S.; Wu, S. I.; Ahn, S. H.; Kim, Y. J

    2004-06-15

    This report has been issued as a result of the surveys of foreign state of the arts on cold neutron source, which was a activity of the project, 'Development of Systems for Cold Neutron Source' commenced on July, 2003. Review and analysis for systems characteristics of the foreign cold neutron source will be a good reference for the basic and detail design starting on the July, 2004. Since the cold neutron source adopts liquid hydrogen or deuterium as a moderator and special field of techniques such as cryogenic cooling system, high vacuum and gas handling, etc., the project started with the survey work in order to be familiar with the concept of the cold neutron source. The survey work was proceeded on the foreign cold neutron sources. This report includes characteristics of the several foreign cold neutron sources.

  1. MPACT Fast Neutron Multiplicity System Prototype Development

    Energy Technology Data Exchange (ETDEWEB)

    D.L. Chichester; S.A. Pozzi; J.L. Dolan; M.T. Kinlaw; S.J. Thompson; A.C. Kaplan; M. Flaska; A. Enqvist; J.T. Johnson; S.M. Watson

    2013-09-01

    This document serves as both an FY2103 End-of-Year and End-of-Project report on efforts that resulted in the design of a prototype fast neutron multiplicity counter leveraged upon the findings of previous project efforts. The prototype design includes 32 liquid scintillator detectors with cubic volumes 7.62 cm in dimension configured into 4 stacked rings of 8 detectors. Detector signal collection for the system is handled with a pair of Struck Innovative Systeme 16-channel digitizers controlled by in-house developed software with built-in multiplicity analysis algorithms. Initial testing and familiarization of the currently obtained prototype components is underway, however full prototype construction is required for further optimization. Monte Carlo models of the prototype system were performed to estimate die-away and efficiency values. Analysis of these models resulted in the development of a software package capable of determining the effects of nearest-neighbor rejection methods for elimination of detector cross talk. A parameter study was performed using previously developed analytical methods for the estimation of assay mass variance for use as a figure-of-merit for system performance. A software package was developed to automate these calculations and ensure accuracy. The results of the parameter study show that the prototype fast neutron multiplicity counter design is very nearly optimized under the restraints of the parameter space.

  2. Neutronic analysis of iter cryopump system

    Energy Technology Data Exchange (ETDEWEB)

    Petrizzi, L. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, I-00044 Frascati, Rome (Italy)], E-mail: petrizzi@frascati.enea.it; Loughlin, M.; Martin, A. [ITER Organization, Cadarache, 13108 St. Paul-lez-Durance (France); Moro, F.; Villari, R. [Associazione EURATOM-ENEA sulla Fusione, Via Enrico Fermi 45, I-00044 Frascati, Rome (Italy); Merola, M.; Pearce, R. [ITER Organization, Cadarache, 13108 St. Paul-lez-Durance (France)

    2009-06-15

    The ITER Vacuum Vessel has upper, equatorial and lower port structures. The bottom ports are dedicated to the divertor replacement (five ports) and to vacuum pumping by means of cryopumps (four ports). The latest cryopump port design is more complex as it has a pump with a direct view of the vessel (upper cryopump) and a second pump at the end of a branch port (lower cryopump). 3D neutronic analyses have been performed in order to study the radiation conditions in and around the port system. In detail, nuclear heating on the cryopump has been calculated updating previous analysis performed in 2003 [L. Petrizzi, ITER CTA Detailed Neutronic Analyses, Final Report on contract EFDA/01-633 ENEA ref NE-VV-R-001 April 2003. Also included in Nuclear Analyis Report NAR ITER ref document G 73 DDD 2W 0.2 (v2.0) March 2006]. Calculations have been performed by means of MCNP 5 Monte Carlo code supplied with FENDL 2.1 library. In this work a new 40 deg. model of ITER has been used in which full details of the cryopump system and remote handling ports have been included as well as the updated divertor components. The paper will present the neutronics results. They consist of nuclear heating on cryopump components; a map of dpa and helium production is provided as well. Gamma doses after shutdown have been calculated around the port flange to have an idea of the possible dose to which the eventual operator will be subject and to plan adequately manual operations. The cryopump is located at a distance of almost 5 m from the mouth of the divertor port and it is 3 m long. Calculations of such deep penetration problem are very challenging require special variance reduction techniques with Monte Carlo codes in order to use in an efficient way the computer resources. These will be described.

  3. Neutronic analysis of iter cryopump system

    International Nuclear Information System (INIS)

    The ITER Vacuum Vessel has upper, equatorial and lower port structures. The bottom ports are dedicated to the divertor replacement (five ports) and to vacuum pumping by means of cryopumps (four ports). The latest cryopump port design is more complex as it has a pump with a direct view of the vessel (upper cryopump) and a second pump at the end of a branch port (lower cryopump). 3D neutronic analyses have been performed in order to study the radiation conditions in and around the port system. In detail, nuclear heating on the cryopump has been calculated updating previous analysis performed in 2003 [L. Petrizzi, ITER CTA Detailed Neutronic Analyses, Final Report on contract EFDA/01-633 ENEA ref NE-VV-R-001 April 2003. Also included in Nuclear Analyis Report NAR ITER ref document G 73 DDD 2W 0.2 (v2.0) March 2006]. Calculations have been performed by means of MCNP 5 Monte Carlo code supplied with FENDL 2.1 library. In this work a new 40 deg. model of ITER has been used in which full details of the cryopump system and remote handling ports have been included as well as the updated divertor components. The paper will present the neutronics results. They consist of nuclear heating on cryopump components; a map of dpa and helium production is provided as well. Gamma doses after shutdown have been calculated around the port flange to have an idea of the possible dose to which the eventual operator will be subject and to plan adequately manual operations. The cryopump is located at a distance of almost 5 m from the mouth of the divertor port and it is 3 m long. Calculations of such deep penetration problem are very challenging require special variance reduction techniques with Monte Carlo codes in order to use in an efficient way the computer resources. These will be described.

  4. Development of a new electronic neutron imaging system

    International Nuclear Information System (INIS)

    An electronic neutron imaging camera system was developed for use with thermal, epithermal, and fast neutrons in applications that include nondestructive inspection of explosives, corrosion, turbine blades, electronics, low Z components, etc. The neutron images are expected to provide information to supplement that available from X-ray tests. The primary camera image area was a 30x30 cm field-of-view with a spatial resolution approaching 1.6 line pairs/mm (lp/mm). The camera had a remotely changeable second lens to limit the field-of-view to 7.6x7.6 cm for high spatial resolution (at least 4 lp/mm) thermal neutron imaging, but neutron and light scatter will limit resolution for fast neutrons to about 0.5 lp/mm. Remote focus capability enhanced camera set-up for optimum operation. The 75 dB dynamic range camera system included 6Li-based screens for imaging of thermal and epithermal neutrons and ZnS(Ag)-based screens for fast neutron imaging. The fast optics was input to a Super S-25 Gen II image intensifier, fiber optically coupled to a 1134 (h)x486 (v) frame transfer CCD camera. The camera system was designed to be compatible with a Navy-sponsored accelerator neutron source. The planned neutron source is an RF quadrupole accelerator that will provide a fast neutron flux of 107 n/cm2-s (at a source distance of 1 m) at an energy of about 2.2 MeV and a thermal neutron flux of 106 n/cm2-s at a source L/D ratio of 30. The electronic camera produced good quality real-time images at these neutron levels. On-chip integration could be used to improve image quality for low flux situations. The camera and accelerator combination provided a useful non-reactor neutron inspection system

  5. Code system for fast reactor neutronics analysis

    International Nuclear Information System (INIS)

    A code system for analysis of fast reactor neutronics has been developed for the purpose of handy use and error reduction. The JOINT code produces the input data file to be used in the neutronics calculation code and also prepares the cross section library file with an assigned format. The effective cross sections are saved in the PDS file with an unified format. At the present stage, this code system includes the following codes; SLAROM, ESELEM5, EXPANDA-G for the production of effective cross sections and CITATION-FBR, ANISN-JR, TWOTRAN2, PHENIX, 3DB, MORSE, CIPER and SNPERT. In the course of the development, some utility programs and service programs have been additionaly developed. These are used for access of PDS file, edit of the cross sections and graphic display. Included in this report are a description of input data format of the JOINT and other programs, and of the function of each subroutine and utility programs. The usage of PDS file is also explained. In Appendix A, the input formats are described for the revised version of the CIPER code. (author)

  6. 21 CFR 892.5300 - Medical neutron radiation therapy system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical neutron radiation therapy system. 892.5300 Section 892.5300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... therapy system. (a) Identification. A medical neutron radiation therapy system is a device intended...

  7. Review of Current Neutron Detection Systems for Emergency Response

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, S. [NSTec; Maurer, R. [NSTec; Guss, P. [NSTec; Kruschwitz, C. [NSTec

    2014-09-01

    Neutron detectors are used in a myriad of applications—from safeguarding special nuclear materials (SNM) to determining lattice spacing in soft materials. The transformational changes taking place in neutron detection and imaging techniques in the last few years are largely being driven by the global shortage of helium-3 (3He). This article reviews the status of neutron sensors used specifically for SNM detection in radiological emergency response. These neutron detectors must be highly efficient, be rugged, have fast electronics to measure neutron multiplicity, and be capable of measuring direction of the neutron sources and possibly image them with high spatial resolution. Neutron detection is an indirect physical process: neutrons react with nuclei in materials to initiate the release of one or more charged particles that produce electric signals that can be processed by the detection system. Therefore, neutron detection requires conversion materials as active elements of the detection system; these materials may include boron-10 (10B), lithium-6 (6Li), and gadollinium-157 (157Gd), to name a few, but the number of materials available for neutron detection is limited. However, in recent years, pulse-shape-discriminating plastic scintillators, scintillators made of helium-4 (4He) under high pressure, pillar and trench semiconductor diodes, and exotic semiconductor neutron detectors made from uranium oxide and other materials have widely expanded the parameter space in neutron detection methodology. In this article we will pay special attention to semiconductor-based neutron sensors. Modern micro-fabricated nanotubes covered inside with neutron converter materials and with very high aspect ratios for better charge transport will be discussed.

  8. Coalescence of Magnetized Binary Neutron Star Systems

    Science.gov (United States)

    Motl, Patrick M.; Anderson, Matthew; Lehner, Luis; Liebling, Steven L.; Neilsen, David; Palenzuela, Carlos; Ponce, Marcelo

    2015-01-01

    We present simulations of the merger of binary neutron star systems calculated with full general relativity and incorporating the global magnetic field structure for the stars evolved with resistive magnetohydrodynamics. Our simulation tools have recently been improved to incorporate the effects of neutrino cooling and have been generalized to allow for tabular equations of state to describe the degenerate matter. Of particular interest are possible electromagnetic counterparts to the gravitational radiation that emerges from these systems. We focus on magnetospheric interactions that ultimately tap into the gravitational potential energy of the binary to power a Poynting flux and deposition of energy through Joule heating and magnetic reconnection. We gratefully acknowledge the support of NASA through the Astrophysics Theory Program grant NNX13AH01G.

  9. Nonreciprocal transmission of neutrons through the noncoplanar magnetic system

    OpenAIRE

    Tatarskiy, D. A.; Petrenko, A. V.; S. N. VDOVICHEV; Udalov, O. G.; Nikitenko, Yu. V.; Fraerman, A. A.

    2014-01-01

    We report on observation of the time reversal symmetry breaking in unpolarized neutrons scattering experiment. Neutron transmittivity through the system consisting of two magnetic mirrors placed in an external magnetic field is measured. Time reversal symmetry holds for coplanar magnetic configuration, meaning that transmitted intensity does not change when interchanging neutron source and detector. Contrarily, for noncoplanar magnetic configuration the time reversal symmetry breaks down. In ...

  10. A Monte Carlo comparison of PGNAA system performance using 252Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Science.gov (United States)

    Naqvi, A. A.

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a 252Cf neutron and a 14-MeV neutron-based prompt γ-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a 252Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt γ-ray yields from the 252Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt γ-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the 252Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  11. A Monte Carlo comparison of PGNAA system performance using {sup 252}Cf neutrons, 2.8-MeV neutrons and 14-MeV neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. E-mail: aanaqvi@kfupm.edu.sa

    2003-10-01

    Monte Carlo simulations were carried out to compare performance of a {sup 252}Cf neutron and a 14-MeV neutron-based prompt {gamma}-ray neutron activation analysis (PGNAA) system with that of the 2.8-MeV neutron-based PGNAA system at King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia. Since the energy of neutron beam used in the KFUPM PGNAA system is very close to that produced by a DD neutron generator, performance comparison between a DD and a DT neutron generator-based PGNAA system is highly desired. For the sake of comparison, the calculations were carried out for the PGNAA system with geometry similar to the KFUPM PGNAA system. These calculations were required to determine improvement in performance of the KFUPM PGNAA system if its 2.8-MeV neutron source is replaced by a {sup 252}Cf neutron source or a 14-MeV neutron source. Results of the calculations revealed that the geometry of the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system are not significantly different but the geometry of the 14-MeV neutron-based system is significantly different from that of the 2.8-MeV neutron-based PGNAA system. Accordingly, the prompt {gamma}-ray yields from the {sup 252}Cf neutron and the 2.8-MeV neutron-based PGNAA system is comparable but prompt {gamma}-ray yields from 14-MeV neutron-based PGNAA system are about three times smaller than that from the 2.8-MeV neutron-based PGNAA system. This study has shown that performance of the {sup 252}Cf neutron-based PGNAA system is comparable with that of the 2.8-MeV neutron-based PGNAA system but the performance of the 14-MeV neutron-based PGNAA system is poorer than that of the 2.8-MeV neutron-based PGNAA system.

  12. Development of a high-speed camera system for neutron imaging at a pulsed neutron source

    International Nuclear Information System (INIS)

    A neutron energy resolved imaging system with a time-of-flight technique has been newly developed and installed at Japan Proton Accelerator Research Complex (J-PARC) with the aim to investigate more preciously and rapidly a spatial distribution of several elements and crystals in various kinds of materials or substances. A high-speed video camera (CMOS, 1300 k frame/s) equipped system allows to obtain TOF images consecutively resolved into narrow energy ranges with a single pulsed neutrons while conventional CCD camera imaging system could obtain only one TOF image in an arbitral neutron energy region in the pulsed neutron energy region from 0.01 eV to a few keV. Qualities of the images obtained with the system, such as spatial resolution (defined by modulation transfer function, 0.8 line-pairs/mm at En∼0.01 eV), dependence of the brightness on the neutron energy and measurement errors (∼2%) of the system were examined experimentally and evaluated by comparison with those of conventional imaging system. The results obtained in the experiments show that the system can visualize the neutron energy resolved images within a small error even at high speed.

  13. Development of cold neutron depth profiling system at HANARO

    Science.gov (United States)

    Park, B. G.; Sun, G. M.; Choi, H. D.

    2014-07-01

    A neutron depth profiling (NDP) system has been designed and developed at HANARO, a 30 MW research reactor at the Korea Atomic Energy Research Institute (KAERI). The KAERI-NDP system utilizes cold neutrons that are transported along the CG1 neutron guide from the cold neutron source and it consists of a neutron beam collimator, a target chamber, a beam stopper, and charged particle detectors along with NIM-standard modules for charged particle pulse-height analysis. A 60 cm in diameter stainless steel target chamber was designed to control the positions of the sample and detector. The energy distribution of the cold neutron beam at the end of the neutron guide was calculated by using the Monte Carlo simulation code McStas, and a neutron flux of 1.8×108 n/cm2 s was determined by using the gold foil activation method at the sample position. The performance of the charged particle detection of the KAERI-NDP system was tested by using Standard Reference Materials. The energy loss spectra of alpha particles and Li ions emitted from 10B, which was irradiated by cold neutrons, were measured. The measured peak concentration and the areal density of 10B in the Standard Reference Material are consistent with the reference values within 1% and 3.4%, respectively.

  14. Compact neutron imaging system using axisymmetric mirrors

    Science.gov (United States)

    Khaykovich, Boris; Moncton, David E; Gubarev, Mikhail V; Ramsey, Brian D; Engelhaupt, Darell E

    2014-05-27

    A dispersed release of neutrons is generated from a source. A portion of this dispersed neutron release is reflected by surfaces of a plurality of nested, axisymmetric mirrors in at least an inner mirror layer and an outer mirror layer, wherein the neutrons reflected by the inner mirror layer are incident on at least one mirror surface of the inner mirror layer N times, wherein N is an integer, and wherein neutrons reflected by the outer mirror are incident on a plurality of mirror surfaces of the outer layer N+i times, where i is a positive integer, to redirect the neutrons toward a target. The mirrors can be formed by a periodically reversed pulsed-plating process.

  15. Modeling the National Ignition Facility neutron imaging system

    International Nuclear Information System (INIS)

    Numerical modeling of the neutron imaging system for the National Ignition Facility (NIF), forward from calculated target neutron emission to a camera image, will guide both the reduction of data and the future development of the system. Located 28 m from target chamber center, the system can produce two images at different neutron energies by gating on neutron arrival time. The brighter image, using neutrons near 14 MeV, reflects the size and symmetry of the implosion ''hot spot.'' A second image in scattered neutrons, 10-12 MeV, reflects the size and symmetry of colder, denser fuel, but with only ∼1%-7% of the neutrons. A misalignment of the pinhole assembly up to ±175 μm is covered by a set of 37 subapertures with different pointings. The model includes the variability of the pinhole point spread function across the field of view. Omega experiments provided absolute calibration, scintillator spatial broadening, and the level of residual light in the down-scattered image from the primary neutrons. Application of the model to light decay measurements of EJ399, BC422, BCF99-55, Xylene, DPAC-30, and Liquid A suggests that DPAC-30 and Liquid A would be preferred over the BCF99-55 scintillator chosen for the first NIF system, if they could be fabricated into detectors with sufficient resolution.

  16. SRAC95; general purpose neutronics code system

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, Keisuke; Tsuchihashi, Keichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kaneko, Kunio

    1996-03-01

    SRAC is a general purpose neutronics code system applicable to core analyses of various types of reactors. Since the publication of JAERI-1302 for the revised SRAC in 1986, a number of additions and modifications have been made for nuclear data libraries and programs. Thus, the new version SRAC95 has been completed. The system consists of six kinds of nuclear data libraries(ENDF/B-IV, -V, -VI, JENDL-2, -3.1, -3.2), five modular codes integrated into SRAC95; collision probability calculation module (PIJ) for 16 types of lattice geometries, Sn transport calculation modules(ANISN, TWOTRAN), diffusion calculation modules(TUD, CITATION) and two optional codes for fuel assembly and core burn-up calculations(newly developed ASMBURN, revised COREBN). In this version, many new functions and data are implemented to support nuclear design studies of advanced reactors, especially for burn-up calculations. SRAC95 is available not only on conventional IBM-compatible computers but also on scalar or vector computers with the UNIX operating system. This report is the SRAC95 users manual which contains general description, contents of revisions, input data requirements, detail information on usage, sample input data and list of available libraries. (author).

  17. The synchronous active neutron detection system for spent fuel assay

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, M.M.; Kendall, P.K.

    1994-10-01

    The authors have begun to develop a novel technique for active neutron assay of fissile material in spent nuclear fuel. This approach will exploit the unique operating features of a 14-MeV neutron generator developed by Schlumberger. This generator and a novel detection system will be applied to the direct measurement of the fissile material content in spent fuel in place of the indirect measures used at present. The technique they are investigating is termed synchronous active neutron detection (SAND). It closely follows a method that has been used routinely in other branches of physics to detect very small signals in the presence of large backgrounds. Synchronous detection instruments are widely available commercially and are termed {open_quotes}lock-in{close_quotes} amplifiers. The authors have implemented a digital lock-in amplifier in conjunction with the Schlumberger neutron generator to explore the possibility of synchronous detection with active neutrons. This approach is possible because the Schlumberger system can operate at up to a 50% duty factor, in effect, a square wave of neutron yield. The results to date are preliminary but quite promising. The system is capable of resolving the fissile material contained in a small fraction of the fuel rods in a cold fuel assembly. It also appears to be quite resilient to background neutron interference. The interrogating neutrons appear to be nonthermal and penetrating. Although a significant amount of work remains to fully explore the relevant physics and optimize the instrument design, the underlying concept appears sound.

  18. Development of a new electronic neutron imaging system

    CERN Document Server

    Brenizer, J S; Gibbs, K M; Mengers, P; Stebbings, C T; Polansky, D; Rogerson, D J

    1999-01-01

    An electronic neutron imaging camera system was developed for use with thermal, epithermal, and fast neutrons in applications that include nondestructive inspection of explosives, corrosion, turbine blades, electronics, low Z components, etc. The neutron images are expected to provide information to supplement that available from X-ray tests. The primary camera image area was a 30x30 cm field-of-view with a spatial resolution approaching 1.6 line pairs/mm (lp/mm). The camera had a remotely changeable second lens to limit the field-of-view to 7.6x7.6 cm for high spatial resolution (at least 4 lp/mm) thermal neutron imaging, but neutron and light scatter will limit resolution for fast neutrons to about 0.5 lp/mm. Remote focus capability enhanced camera set-up for optimum operation. The 75 dB dynamic range camera system included sup 6 Li-based screens for imaging of thermal and epithermal neutrons and ZnS(Ag)-based screens for fast neutron imaging. The fast optics was input to a Super S-25 Gen II image intensifi...

  19. Neutron spatial flux profile measurement in compact subcritical system using miniature neutron detectors

    International Nuclear Information System (INIS)

    A zero power multiplying assembly in subcritical regime serves as a benchmark for validating subcritical reactor physics. The utilization of a subcritical assembly for the determination of nuclear parameters in a multiplying medium requires a well-defined neutron flux to carry out the experiments. For this it is necessary to know the neutron flux profile inside a subcritical system. A compact subcritical assembly BRAHMMA has been developed in India. The experimental channels in this assembly are typically less than 8 mm diameter. This requires use of miniature detectors that can be mounted in these experimental channels. In this article we present the thermal neutron flux profile measurement in a compact subcritical system using indigenously developed miniature gas filled neutron detectors. These detectors were specially designed and fabricated considering the restrictive dimensional requirements of the subcritical core. Detectors of non-standard size with various sensitivities, from 0.4 to 0.001 cps/nv were used for neutron flux of interest ranging from 103 to 107 n-cm−2 s−1. A comparison of measured neutron flux using these detectors and simulated Monte Carlo calculations are also presented in this article

  20. SRAC2006: A comprehensive neutronics calculation code system

    International Nuclear Information System (INIS)

    The SRAC is a code system applicable to neutronics analysis of a variety of reactor types. Since the publication of the second version of the users manual (JAERI-1302) in 1986 for the SRAC system, a number of additions and modifications to the functions and the library data have been made to establish a comprehensive neutronics code system. The current system includes major neutron data libraries (JENDL-3.3, JENDL-3.2, ENDF/B-VII, ENDF/B-VI.8, JEFF-3.1, JEF-2.2, etc.), and integrates five elementary codes for neutron transport and diffusion calculation; PIJ based on the collision probability method applicable to 16 kind of lattice models, SN transport codes ANISN(1D) and TWOTRN(2D), diffusion codes TUD(1D) and CITATION(multi-D). The system also includes an auxiliary code COREBN for multi-dimensional core burn-up calculation. (author)

  1. Operation manual for Sandia MA165 neutron generator system

    International Nuclear Information System (INIS)

    The Sandia MA165 Neutron Generator System was designed for use in the Sandia Safeguards Unattended Equipment/Material Pass-Through. As this neutron generator system design evolved, it became simpler to use while it also became more versatile. Two operations which were previously controlled manually by the operator were automated in the new design. Its stand alone characteristic has allowed it to become a versatile laboratory tool. Los Alamos National Scientific Laboratory and Brookhaven National Laboratory are both currently using versions of the MA165 system for their research. Aside from power supplies, the system consists of a neutron generator package and an electronic control chassis. This manual describes, in detail, the neutron generator package, the theory of operation of the electronic control chassis, and instructions for using the MA165 system

  2. Application Research of Developed Drummed Nuclear Waste Neutron Counting System

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The application researches such as variety of factors affecting the measurement, calibrating etc. are need before the drummed nuclear waste neutron counting system (WNC) can be really put into use after installed at the site.

  3. IEC-Based Neutron Generator for Security Inspection System

    International Nuclear Information System (INIS)

    Large nuclear reactors are widely employed for electricity power generation, but small nuclear radiation sources can also be used for a variety of industrial/government applications. In this paper we will discuss the use of a small neutron source based on Inertial Electrostatic Confinement (IEC) of accelerated deuterium ions. There is an urgent need of highly effective detection systems for explosives, especially in airports. While current airport inspection systems are strongly based on X-ray technique, neutron activation including Thermal Neutron Analysis (TNA) and Fast Neutron Analysis (FNA) is powerful in detecting certain types of explosives in luggage and in cargoes. Basic elements present in the explosives can be measured through the (n, n'?) reaction initiated by fast neutrons. Combined with a time-of-flight technique, a complete imaging of key elements, hence of the explosive materials, is obtained. Among the various neutron source generators, the IEC is an ideal candidate to meet the neutron activation analysis requirements. Compared with other accelerators and radioisotopes such as 252Cf, the IEC is simpler, can be switched on or off, and can reliably produce neutrons with minimum maintenance. Theoretical and experimental studies of a spherical IEC have been conducted at the University of Illinois. In a spherical IEC device, 2.54-MeV neutrons of ∼108 n/s via DD reactions over recent years or 14-MeV neutrons of ∼2x1010 n/s via DT reactions can be obtained using an ion gun injection technique. The possibility of the cylindrical IEC in pulsed operation mode combining with pulsed FNA method would also be discussed. In this paper we examine the possibility of using an alternative cylindrical IEC configuration. Such a device was studied earlier at the University of Illinois and it provides a very convenient geometry for security inspection. However, to calculate the neutron yield precisely with this configuration, an understanding of the potential wall

  4. On generating neutron transport tables with the NJOY system

    Energy Technology Data Exchange (ETDEWEB)

    Caldeira, Alexandre D.; Claro, Luiz H., E-mail: alexdc@ieav.cta.br, E-mail: luizhenu@ieav.cta.br [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil)

    2013-07-01

    Incorrect values for the product of the average number of neutrons released per fission and the fission microscopic cross-section were detected in several energy groups of a neutron transport table generated with the most updated version of the NJOY system. It was verified that the problem persists when older versions of this system are utilized. Although this problem exists for, at least, ten years, it is still an open question. (author)

  5. An application of the neutron television fluoroscopic system to neutron computed tomography

    Science.gov (United States)

    Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji

    1984-10-01

    Recently the real-time neutron radiography system of the Kyoto University Reactor (KUR) has been developed and practically applied to penetrating the side plates of the MTR type reactor fuels and investigation of moving objects. In this paper an application of the KUR neutron TV system to neutron computed tomography (NCT) is described. By using the NTV system, projection data can be acquired in a single measurement and simultaneously the projection image can be observed on a CRT monitor. The Fourier-convolution technique is used to produce the reconstructed image and its image has a good enough quality for revealing water in a small hole of 1.5 mm in diameter.

  6. Characterization of a neutron–beta counting system with beta-delayed neutron emitters

    OpenAIRE

    Agramunt, J.; Tain, J.L.; Gómez-Hornillos, M. B.; GARCIA A. R.; Albiol, F; Algora, A.; Caballero-Folch, R.; CALVIÑO F.; Cano-Ott, D.; Cortés, G.; Domingo-Pardo, C.; Eronen, Tommi; Gelletly, W.; Gorelov, Dmitry; Gorlychev, V.

    2016-01-01

    A new detection system for the measurement of beta-delayed neutron emission probabilities has been characterized using fission products with well known β-delayed neutron emission properties. The setup consists of BELEN-20, a 4π neutron counter with twenty 3He proportional tubes arranged inside a large polyethylene neutron moderator, a thin Si detector for β counting and a selftriggering digital data acquisition system. The use of delayed-neutron precursors with different neutron emis...

  7. Application of hydrogel system for neutron attenuation

    CERN Document Server

    Gupta, S C; Gupta, B P

    2000-01-01

    Hydrogel sheets based on poly(vinyl alcohol) (PVA) and poly(vinyl acetate) (PVAc) have been prepared by the technique of acetalization of PVA using formaldehyde and grafting of acrylic acid onto PVAc by gamma irradiation. PVA hydrogel (PVAB) sheets have been prepared in geometrically stable shapes by compression moulding process and characterised for their thermal properties, geometrical stability on water absorption, and neutron shielding efficiency. The effective protection from fast neutrons can be increased by a factor of 18% by swelling the PVAB sheets to 210% in water. The water intake and subsequent retention of water by the sheet can be tailored as per shielding requirements.

  8. An automatic evaluation system for NTA film neutron dosimeters

    CERN Document Server

    Müller, R

    1999-01-01

    At CERN, neutron personal monitoring for over 4000 collaborators is performed with Kodak NTA films, which have been shown to be the most suitable neutron dosimeter in the radiation environment around high-energy accelerators. To overcome the lengthy and strenuous manual scanning process with an optical microscope, an automatic analysis system has been developed. We report on the successful automatic scanning of NTA films irradiated with sup 2 sup 3 sup 8 Pu-Be source neutrons, which results in densely ionised recoil tracks, as well as on the extension of the method to higher energy neutrons causing sparse and fragmentary tracks. The application of the method in routine personal monitoring is discussed. $9 overcome the lengthy and strenuous manual scanning process with an optical microscope, an automatic analysis system has been developed. We report on the successful automatic scanning of NTA films irradiated with /sup 238/Pu-Be source $9 discussed. (10 refs).

  9. Neutronics of fluid fuel system with perfect remixing

    International Nuclear Information System (INIS)

    The neutronics of a homogeneous fluid-fuel nuclear system with perfect remixing implying a uniform distribution of delayed neutron precursors inside the core is studied in this work. A one-group diffusion model is adopted for the neutron balance and an analytical treatment is used throughout the whole analysis. The critical problem is first solved, allowing the determination of a set of eigenfunctions characteristic of the physico-mathematical problem considered. The time-dependent problem is then solved by expanding the neutron flux in terms of these eigenfunctions and the results are compared with those obtained through a standard Helmholtz eigenfunction expansion. The use of these eigenfunctions show to be advantageous, since the asymptotic state of the system can be represented by the fundamental eigenfunction only. (author)

  10. Neutronic predesign tool for fusion power reactors system assessment

    Energy Technology Data Exchange (ETDEWEB)

    Jaboulay, J.-C., E-mail: jean-charles.jaboulay@cea.fr [CEA, DEN, Saclay, DM2S, SERMA, F-91191 Gif-sur-Yvette (France); Li Puma, A. [CEA, DEN, Saclay, DM2S, SERMA, F-91191 Gif-sur-Yvette (France); Martínez Arroyo, J. [ETSEIB, Internship in CEA (Spain)

    2013-10-15

    SYCOMORE, a fusion reactor system code based on a modular approach, is under development at CEA. In this framework, this paper describes a methodology developed to build the neutronic module of SYCOMORE. This neutronic module aims to evaluate main neutronic parameters characterising a fusion reactor (tokamak): tritium breeding ratio, multiplication factor, nuclear heating as a function of the reactor main geometrical parameters (major radius, elongation, etc.), of the radial build, Li enrichment, blanket and shield thickness, etc. It is based on calculations carried out with APOLLO2 and TRIPOLI-4 CEA transport code on simplified 1D and 2D neutronic models. These models are validated versus a more detailed 3D Monte-Carlo model (using TRIPOLI-4). To ease the integration of this neutronic module in SYCOMORE and provide results instantly, a surrogate model that replicates the 1D and 2D neutronic model results was used. Among the different surrogate models types (polynomial interpolation, responses functions, interpolating by Kriging, artificial neural network, etc.) the neural networks were selected for their efficiency and flexibility. The methodology described in this paper to build SYCOMORE neutronic module is devoted to HCLL blanket, but it could be applied to any breeder blanket concept provided that appropriate validation could be carried out.

  11. Measurement of anomalous neutron from deuterium/solid system

    International Nuclear Information System (INIS)

    A series of experiments on both D2O electrolysis and thermal cycle of deuterium absorbed Ti Turnings are designed to examine the anomalous phenomena in Deuterium/Solid System. A neutron detector containing 16 BF3 tubes with a detection limit of 0.38 n/s for two hour counting is used for electrolysis experiments. No neutron counting rate statistically higher than detection limit is observed from Fleischmann and Pons type experiments. An HLNCC-II neutron detector equipped with 18 3He tubes and a JSR-11 shift register unit with a detection limit of 0.20 n/s for a two hour run are employed to study the neutron signals in D2 gas experiments. Ten batches of dry fusion samples are tested, among them, seven batches with neutron burst signals occur roughly at the temperature from -100 degrees centigrade to near room temperature. In the first four runs of a typical sample batch, seven neutron bursts are observed with neutron numbers from 15 to 482,which are 3 and 75 times, respectively, higher than the uncertainty of background. However, no bursts happened for H2 dummy samples running in between and afterwards and for sample batch after certain runs

  12. Measurement of anomalous neutron from deuterium/solid system

    International Nuclear Information System (INIS)

    A series of experiments on both D2O electrolysis and thermal cycle of deuterium absorbed Ti Turnings are designed to examine the anomalous phenomena in Deuterium/Solid System. A neutron detector containing 16 BF3 tubes with a detection limit of 0.38 n/s for two hour counting is used for electrolysis experiments. No neutron counting rate statistically higher than detection limit is observed from Fleischmann and Pons type experiments. An HLNCC-II neutron detector equipped with 18 3He tubes and JSR-11 shift register unit with a detection limit of 0.20 n/s for a two hour run are employed to study the neutron signals in D2 gas experiments. Ten batches of dry fusion samples are tested, among them, seven batches with neutron burst signals occur roughly at the temperature from -100 degrees centigrade to near room temperature. In the first four runs of a typical sample batch, seven neutron bursts are observed with neutron numbers from 15 to 482, which are 3 and 75 times, respectively, higher than the uncertainty of background. However, no bursts happened for H2 dummy samples running in-between and afterwards and for sample batch after certain runs

  13. A guide to the AUS modular neutronics code system

    International Nuclear Information System (INIS)

    A general description is given of the AUS modular neutronics code system, which may be used for calculations of a very wide range of fission reactors, fusion blankets and other neutron applications. The present system has cross-section libraries derived from ENDF/B-IV and includes modules which provide for lattice calculations, one-dimensional transport calculations, and one, two, and three-dimensional diffusion calculations, burnup calculations and the flexible editing of results. Details of all system aspects of AUS are provided but the major individual modules are only outlined. Sufficient information is given to enable other modules to be added to the system

  14. Review of neutron radiographic applications in industrial and biological systems

    International Nuclear Information System (INIS)

    Neutron radiography is a non-destructive testing technique and is being used worldwide for the design and the development of reactor fuels for research and power reactors. It is also being used for non-destructive examination of nuclear industrial products. In addition to its explosives and other industrial sectors. In addition to its applications in industrial sectors, the technique is widely used for research and development activities in biological systems. A review of technical applications of neutron radiography in different fields particularly in nuclear fuel management, aerospace industry, explosives and biology is presented. The methodology of neutron radiography is also discussed in detail along with the advantages of the technique. In addition, the potential of the neutron radiography facility at PINSTECH has been described. (author)

  15. Configuration for the WNR data acquisition system for neutron measurements

    International Nuclear Information System (INIS)

    The configuration for a new data acquisition system for the Weapons Neutron Research Facility at the Los Alamos National Laboratory is introduced. The system utilizes a FASTBUS front-end for real-time data collection and DEC computers for the experiment control and analysis. A local area network is used extensively within the overall system. 6 refs., 3 figs

  16. In situ measurements of neutron multiplying systems

    International Nuclear Information System (INIS)

    Historical and recent examples of the application of in situ measurements to provide knowledge for specific operations and general criticality safety guidance are reviewed. The importance of the American National Standard, Safety in Conducting Subcritical Neutron-Multiplication Measurements In Situ, ANSI/ANS-8.6, 1988 is discussed. Examples of possible future applications of in-situ measurements are provided. 4 refs., 4 figs

  17. SPECTRON, a neutron noise measurement system in frequency domain

    International Nuclear Information System (INIS)

    This paper is dedicated to the presentation and validation of SPECTRON, a novel neutron noise measurement system developed at CEA Cadarache. The device is designed for the measurement of the βeff parameter (effective fraction of delayed neutrons) of experimental nuclear reactors using the Cohn-α method. An integrated electronic system is used to record the current from fission chambers. Spectra computed from measurement data are processed by a dedicated software in order to estimate the reactor transfer function and then the effective fraction of delayed neutrons as well as the prompt neutron generation time. After a review of the pile noise measurement method in current mode, the SPECTRON architecture is presented. Then, the validation procedure is described and experimental results are shown, supporting the proper functioning of this new measurement system. It is shown that every technical requirement needed for correct measurement of neutron noise is fulfilled. Measurements performed at MINERVE and EOLE, two experimental nuclear reactors at CEA Cadarache, in real conditions allowed us to validate SPECTRON

  18. SPECTRON, a neutron noise measurement system in frequency domain

    Energy Technology Data Exchange (ETDEWEB)

    Izarra, G. de; Jammes, C., E-mail: christian.jammes@cea.fr; Destouches, C. [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 Saint-Paul-lez-Durance (France); Geslot, B.; Di Salvo, J. [CEA, DEN, DER, Experimental Programs Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France)

    2015-11-15

    This paper is dedicated to the presentation and validation of SPECTRON, a novel neutron noise measurement system developed at CEA Cadarache. The device is designed for the measurement of the β{sub eff} parameter (effective fraction of delayed neutrons) of experimental nuclear reactors using the Cohn-α method. An integrated electronic system is used to record the current from fission chambers. Spectra computed from measurement data are processed by a dedicated software in order to estimate the reactor transfer function and then the effective fraction of delayed neutrons as well as the prompt neutron generation time. After a review of the pile noise measurement method in current mode, the SPECTRON architecture is presented. Then, the validation procedure is described and experimental results are shown, supporting the proper functioning of this new measurement system. It is shown that every technical requirement needed for correct measurement of neutron noise is fulfilled. Measurements performed at MINERVE and EOLE, two experimental nuclear reactors at CEA Cadarache, in real conditions allowed us to validate SPECTRON.

  19. SPECTRON, a neutron noise measurement system in frequency domain.

    Science.gov (United States)

    de Izarra, G; Jammes, C; Geslot, B; Di Salvo, J; Destouches, C

    2015-11-01

    This paper is dedicated to the presentation and validation of SPECTRON, a novel neutron noise measurement system developed at CEA Cadarache. The device is designed for the measurement of the β(eff) parameter (effective fraction of delayed neutrons) of experimental nuclear reactors using the Cohn-α method. An integrated electronic system is used to record the current from fission chambers. Spectra computed from measurement data are processed by a dedicated software in order to estimate the reactor transfer function and then the effective fraction of delayed neutrons as well as the prompt neutron generation time. After a review of the pile noise measurement method in current mode, the SPECTRON architecture is presented. Then, the validation procedure is described and experimental results are shown, supporting the proper functioning of this new measurement system. It is shown that every technical requirement needed for correct measurement of neutron noise is fulfilled. Measurements performed at MINERVE and EOLE, two experimental nuclear reactors at CEA Cadarache, in real conditions allowed us to validate SPECTRON.

  20. Design of a system for neutrons dosimetry; Diseno de un sistema para dosimetria de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Ceron, P.; Rivera, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Paredes G, L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Sanchez, A. [IPN, Escuela Superior de Fisica y Matematicas, Av. Instituto Politecnico Nacional s/n, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico); Vega C, H. R., E-mail: victceronr@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-08-15

    At the present time diverse systems of detection of neutrons exist, as proportional counters based on BF{sub 3}, He{sub 3} and spectrometers of Bonner spheres. However, the cost and the complexity of the implementation of these systems put them far from the reach for dosimetric purposes. For these reasons a system of neutrons detection composed by a medium paraffin moderator that forms a 4π (spheres) arrangement and of several couples of thermoluminescent dosimeters TLD 600/TLD 700. The response of the system presents a minor repeatability to 5% in several assays when being irradiated with a {sup 239}PuBe source and a deviation of 13.8% in the Tl readings of four different spheres. The calibration factor of the system with regard to the neutrons source which was of 56.2 p Sv/nc also was calculated. These detectors will be used as passive monitors of photoneutrons in a radiotherapy room with lineal accelerator of high energy. (Author)

  1. Development of Library Processing System for Neutron Transport Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Song, J. S.; Park, S. Y.; Kim, H. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)] (and others)

    2008-12-15

    A system for library generation was developed for the lattice neutron transport program for pressurized water reactor core analysis. The system extracts multi energy group nuclear data for requested nuclides from ENDF/B whose data are based on continuous energy, generates hydrogen equivalent factor and resonance integral table as functions of temperature and background cross section for resonance nuclides, generates subgroup data for the lattice program to treat resonance exactly as possible, and generates multi-group neutron library file including nuclide depletion data for use of the lattice program.

  2. Development of a system for neutron radiography and tomography

    Science.gov (United States)

    Mühlbauer, Martin J.; Calzada, Elbio; Schillinger, Burkhard

    2005-04-01

    Neutron radiography and tomography are getting more and more popular. Since they use the white thermal neutron spectrum, they are especially feasible even at small neutron sources, where the flux is too low for efficient scattering experiments requiring monochromatization of the beam. High-end tomography systems require the investment of several ten thousand Euros, with the costs often hindering the initiative for a new tomography setup. Based on the experiences gathered at Technische Universitaet Muenchen, we developed a cheaper system based on standard components that cannot compete with the sensitivity of a high-grade system, but is perfectly capable of doing neutron radiography and tomography. The system is meant as a startup construction kit for initiating tomography programs even at small neutron sources. The system is built from scratch, enabling the user to gain an understanding for the influence of each component on the image results. With the experience thus gained, he should be able to design his next and more advanced system by himself. To keep the whole system simple and cheap (the price should reach only a few percent of a high-end system), standard parts are used whenever possible, and all components are designed in such a way that they can be built without special equipment. Public domain and freeware software is used for data processing. Such a system is being built at FRM2 in Garching within the scope of a master thesis. After completion, a website will be installed with descriptions, diagrams and software for building and operating the system. Both hardware and software are discussed.

  3. Development of inverse-planning system for neutron capture therapy

    International Nuclear Information System (INIS)

    To lead proper irradiation condition effectively, Japan Atomic Energy Agency (JAEA) is developing an inverse-planning system for neutron capture therapy (NCT-IPS) based on the JAEA computational dosimetry system (JCDS) for BNCT. The leading methodology of an optimum condition in the NCT-IPS has been applied spatial channel theory with adjoint flux solution of Botzman transport. By analyzing the results obtained from the adjoint flux calculations according to the theory, optimum incident point of the beam against the patient can be found, and neutron spectrum of the beam which can generate ideal distribution of neutron flux around tumor region can be determined. The conceptual design of the NCT-IPS was investigated, and prototype of NCT-IPS with JCDS is being developed. (author)

  4. Analysis of neutron flux measurement systems using statistical functions

    International Nuclear Information System (INIS)

    This work develops an integrated analysis for neutron flux measurement systems using the concepts of cumulants and spectra. Its major contribution is the generalization of Campbell's theorem in the form of spectra in the frequency domain, and its application to the analysis of neutron flux measurement systems. Campbell's theorem, in its generalized form, constitutes an important tool, not only to find the nth-order frequency spectra of the radiation detector, but also in the system analysis. The radiation detector, an ionization chamber for neutrons, is modeled for cylindrical, plane and spherical geometries. The detector current pulses are characterized by a vector of random parameters, and the associated charges, statistical moments and frequency spectra of the resulting current are calculated. A computer program is developed for application of the proposed methodology. In order for the analysis to integrate the associated electronics, the signal processor is studied, considering analog and digital configurations. The analysis is unified by developing the concept of equivalent systems that can be used to describe the cumulants and spectra in analog or digital systems. The noise in the signal processor input stage is analysed in terms of second order spectrum. Mathematical expressions are presented for cumulants and spectra up to fourth order, for important cases of filter positioning relative to detector spectra. Unbiased conventional estimators for cumulants are used, and, to evaluate systems precision and response time, expressions are developed for their variances. Finally, some possibilities for obtaining neutron radiation flux as a function of cumulants are discussed. In summary, this work proposes some analysis tools which make possible important decisions in the design of better neutron flux measurement systems. (author)

  5. Integrity of neutron-absorbing components of LWR fuel systems

    International Nuclear Information System (INIS)

    A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs

  6. Integrity of neutron-absorbing components of LWR fuel systems

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, W.J.; Berting, F.M.

    1991-03-01

    A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs.

  7. Systems for neutronic, thermohydraulic and shielding calculation in personal computers

    International Nuclear Information System (INIS)

    The MTR-PC (Materials Testing Reactors-Personal Computers) system has been developed by the Nuclear Engineering Division of INVAP S.E. with the aim of providing working conditions integrated with personal computers for design and neutronic, thermohydraulic and shielding analysis for reactors employing plate type fuel. (Author)

  8. Reflection of neutrons from fan-like magnetic systems

    OpenAIRE

    Ignatovich, V. K.; Radu, F.

    2009-01-01

    An analytical solution is found for neutron reflection coefficients from magnetic mirrors with fan-like magnetization. The main feature of the reflection curves related to this type of magnetization is pointed out. The results of calculations for some parameters of the system are presented. Time parity and detailed balance violation in the model are discussed.

  9. Multisphere neutron spectrometric system with thermoluminescence dosemeters: sensitive improvement.

    Science.gov (United States)

    Gregori, B; Papadópulos, S; Cruzate, J; Kunst, J J

    2002-01-01

    In this work, a neutron spectrometric system based on a set of moderating spheres with thermoluminescence detectors (TLD) is presented. The system at the Nuclear Regulatory Authority (ARN) Dosimetry Laboratory consists of 12 solid spheres made of high-density polyethylene (p = 0.95 g x cm(-3)), with diameters ranging from 2" to 12" and TLD sensitive to thermal and gamma radiation, namely TLD-600 and TLD-700, located at the centre of the spheres. The neutron response matrix for this Bonner Sphere Spectrometer (BSS) was calculated using the MCNP-IVB code and the library ENDF/B-VI in the energy range between thermal neutrons and 100 MeV. The neutron spectrum was obtained using the LOUH182 unfolding code. The improvement in sensitivity of the system is based on the election of a different heating cycle of the TLD that allows an increase in sensitivity by a factor of 2.6 compared with the standard laboratory treatment. The system response for the calibration with an Am-Be source is presented.

  10. Neutron conversion and cascaded cooling in paramagnetic systems for a high-flux source of very cold neutrons

    Science.gov (United States)

    Zimmer, Oliver

    2016-03-01

    A new neutron-cooling mechanism is proposed with potential benefits for novel intense sources of very cold neutrons with wavelengths >2 nm, and for enhancing the production of ultracold neutrons. It employs inelastic magnetic scattering in weakly absorbing, cold paramagnetic systems. Kinetic energy is removed from the neutron stepwise in constant decrements determined by the Zeeman energy of paramagnetic atoms or ions in an external magnetic field, or by zero-field level splittings in magnetic molecules. The stationary neutron transport equation is analyzed for an infinite, homogeneous medium with Maxwellian neutron sources, using inelastic scattering cross sections derived in an appendix. Nonmagnetic inelastic scattering processes are neglected. The solution therefore still underestimates very cold neutron densities that should be achievable in a real medium. Molecular oxygen with its triplet ground state appears particularly promising, notably as a host in fully deuterated O2-clathrate hydrate. Other possibilities are dry O2-4He van der Waals clusters and O2 intercalated in fcc-C60. For conversion of cold to ultracold neutrons, where an incident neutron imparts only a single energy quantum to the medium, the paramagnetic scattering in the clathrate system is found to be stronger, by more than an order of magnitude, than the single-phonon emission in superfluid helium, when evaluated for an incident neutron spectrum with the optimum temperature for the respective medium. Moreover, the multistep paramagnetic cooling cascade leads to further strong enhancements of very cold neutron densities, e.g., by a factor 14 (57) for an initial neutron temperature of 30 K (100 K ), for the moderator held at about 1.3 K . Due to a favorable Bragg cutoff of the O2 clathrate, the cascade-cooling can take effect in a moderator with linear extensions smaller than a meter.

  11. Development of a Neutron Spectroscopic System Utilizing Compressed Sensing Measurements

    Directory of Open Access Journals (Sweden)

    Vargas Danilo

    2016-01-01

    Full Text Available A new approach to neutron detection capable of gathering spectroscopic information has been demonstrated. The approach relies on an asymmetrical arrangement of materials, geometry, and an ability to change the orientation of the detector with respect to the neutron field. Measurements are used to unfold the energy characteristics of the neutron field using a new theoretical framework of compressed sensing. Recent theoretical results show that the number of multiplexed samples can be lower than the full number of traditional samples while providing the ability to have some super-resolution. Furthermore, the solution approach does not require a priori information or inclusion of physics models. Utilizing the MCNP code, a number of candidate detector geometries and materials were modeled. Simulations were carried out for a number of neutron energies and distributions with preselected orientations for the detector. The resulting matrix (A consists of n rows associated with orientation and m columns associated with energy and distribution where n < m. The library of known responses is used for new measurements Y (n × 1 and the solver is able to determine the system, Y = Ax where x is a sparse vector. Therefore, energy spectrum measurements are a combination of the energy distribution information of the identified elements of A. This approach allows for determination of neutron spectroscopic information using a single detector system with analog multiplexing. The analog multiplexing allows the use of a compressed sensing solution similar to approaches used in other areas of imaging. A single detector assembly provides improved flexibility and is expected to reduce uncertainty associated with current neutron spectroscopy measurement.

  12. Development of a Neutron Spectroscopic System Utilizing Compressed Sensing Measurements

    Science.gov (United States)

    Vargas, Danilo; Cable Kurwitz, R.; Carron, Igor; DePriest, K. Russell

    2016-02-01

    A new approach to neutron detection capable of gathering spectroscopic information has been demonstrated. The approach relies on an asymmetrical arrangement of materials, geometry, and an ability to change the orientation of the detector with respect to the neutron field. Measurements are used to unfold the energy characteristics of the neutron field using a new theoretical framework of compressed sensing. Recent theoretical results show that the number of multiplexed samples can be lower than the full number of traditional samples while providing the ability to have some super-resolution. Furthermore, the solution approach does not require a priori information or inclusion of physics models. Utilizing the MCNP code, a number of candidate detector geometries and materials were modeled. Simulations were carried out for a number of neutron energies and distributions with preselected orientations for the detector. The resulting matrix (A) consists of n rows associated with orientation and m columns associated with energy and distribution where n library of known responses is used for new measurements Y (n × 1) and the solver is able to determine the system, Y = Ax where x is a sparse vector. Therefore, energy spectrum measurements are a combination of the energy distribution information of the identified elements of A. This approach allows for determination of neutron spectroscopic information using a single detector system with analog multiplexing. The analog multiplexing allows the use of a compressed sensing solution similar to approaches used in other areas of imaging. A single detector assembly provides improved flexibility and is expected to reduce uncertainty associated with current neutron spectroscopy measurement.

  13. Data acquisition and instrument control system for neutron spectrometers

    Indian Academy of Sciences (India)

    S S Naik; Ismat Kotwal; R M Chandak; V G Gaonkar

    2004-08-01

    A personal computer (PC)-based data acquisition and instrument control system has been developed for neutron spectrometers in Dhruva reactor hall and Guide Tube laboratory. Efforts have been made to make the system versatile so that it can be used for controlling various neutron spectrometers using single end-on detector in step scan mode. Commercially available PC add-on cards have been used for input–output and timer-counter operations. An interface card and DC motor driver card have been developed indigenously. Software for the system has been written in Visual C++ language using MS Windows operating system. This data acquisition and instrument control system is successfully controlling four spectrometers at Dhruva reactor.

  14. Modelling and control of neutron and synchrotron beamline positioning systems

    Science.gov (United States)

    Nneji, S. O.; Zhang, S. Y.; Kabra, S.; Moat, R. J.; James, J. A.

    2016-03-01

    Measurement of residual stress using neutron or synchrotron diffraction relies on the accurate alignment of the sample in relation to the gauge volume of the instrument. Automatic sample alignment can be achieved using kinematic models of the positioning system provided the relevant kinematic parameters are known, or can be determined, to a suitable accuracy. In this paper, the use of techniques from robotic calibration theory to generate kinematic models of both off-the-shelf and custom-built positioning systems is demonstrated. The approach is illustrated using a positioning system in use on the ENGIN-X instrument at the UK's ISIS pulsed neutron source comprising a traditional XYZΩ table augmented with a triple axis manipulator. Accuracies better than 100 microns were achieved for this compound system. Discussed here in terms of sample positioning systems these methods are entirely applicable to other moving instrument components such as beam shaping jaws and detectors.

  15. Simulation of differential response functions of the neutron technological control system of a solvent vessel from a local source of neutrons

    International Nuclear Information System (INIS)

    In order to forecast the parameters of the neutron process monitoring system, a computer model of the dissolver with the neutron detection blocks has been developed. The results of the computer model verification based on the measurement results of differential response functions of neutron detectors using the fast-neutron source on the RPSK-type dissolver have been presented

  16. Neutron-deuteron system and the photon polarization parameter at thermal neutron energies

    Science.gov (United States)

    Sadeghi, H.

    2007-04-01

    Effective field theory (EFT) is the unique, model independent and systematic low-energy version of QCD for processes involving momenta below the pion mass. A low-energy photonuclear observable in three-body systems, photon polarization parameter at thermal neutron energies is calculated by using pionless EFT up to next-to-next to leading order (NLO2). In order to make a comparative study of this model, we compared our results for photon polarization parameter with the realistic Argonne v18 two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions. Three-body currents give small but significant contributions to some of the observables in the neutron-deuteron radiative capture cross section at thermal neutron energies. In this formalism the three-nucleon forces are needed up to NLO2 for cut-off independent results. Our result converges order by order in low energy expansion and also cut-off independent at this order.

  17. Neutron-Deuteron System and Photon Polarization Parameter at Thermal Neutron Energies

    CERN Document Server

    Sadeghi, H

    2007-01-01

    Effective Field Theory(EFT) is, the unique, model independent and systematic low-energy version of QCD for processes involving momenta below the pion mass. A low-energy photo-nuclear observable in three-body systems, photon polarization parameter at thermal neutron energies is calculated by using pionless EFT up to next-to-next to leading order(N$^2$LO). In order to make a comparative study of this model, we compared our results for photon polarization parameter with the realistic Argonne $v_{18}$ two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions. Three-body currents give small but significant contributions to some of the observables in the neutron-deuteron radiative capture cross section at thermal neutron energies. In this formalism the three-nucleon forces are needed up to N$^2$LO for cut-off independent results. Our result converges order by order in low energy expansion and also cut-off independent at this order.

  18. LANSCE (Los Alamos Neutron Scattering Center) target system performance

    International Nuclear Information System (INIS)

    The authors measured neutron beam fluxes at LANSCE using gold foil activation techniques. They did an extensive computer simulation of the as-built LANSCE Target/Moderator/Reflector/Shield geometry. They used this mockup in a Monte Carlo calculation to predict LANSCE neutronic performance for comparison with measured results. For neutron beam fluxes at 1 eV, the ratio of measured data to calculated varies from ∼0.6-0.9. The computed 1 eV neutron leakage at the moderator surface is 3.9 x 1010 n/eV-sr-s-μA for LANSCE high-intensity water moderators. The corresponding values for the LANSCE high-resolution water moderator and the liquid hydrogen moderator are 3.3 and 2.9 x 1010, respectively. LANSCE predicted moderator intensities (per proton) for a tungsten target are essentially the same as ISIS predicted moderator intensities for a depleted uranium target. The calculated LANSCE steady state unperturbed thermal (E 13 n/cm2-s. The unique LANSCE split-target/flux-trap-moderator system is performing exceedingly well. The system has operated without a target or moderator change for over three years at nominal proton currents of 25 μA of 800-MeV protons. 17 refs., 8 figs., 3 tabs

  19. Neutron-based land mine detection system development

    Energy Technology Data Exchange (ETDEWEB)

    Davis, H.A.; McDonald, T.E. Jr.; Nebel, R.A.; Pickrell, M.M.

    1997-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to examine the feasibility of developing a land mine detection system that can detect nonmetallic (plastic) mines using the detection and analysis of prompt gamma neutron activation analysis (PGNAA). The authors approached this study by first carrying out a review of other nonmetallic land mine detection methods for comparison with the PGNAA concept. They reviewed issues associated with detecting and recording the return gamma signal resulting from neutrons interacting with high explosive in mines and they examined two neutron source technologies that have been under development at Los Alamos for the past several years for possible application to a PGNAA system. A major advantage of the PGNAA approach is it`s ability to discriminate detection speed and need for close proximity. The authors identified approaches to solving these problems through development of improved neutron sources and detection sensors.

  20. Development of the prototype pneumatic transfer system for ITER neutron activation system.

    Science.gov (United States)

    Cheon, M S; Seon, C R; Pak, S; Lee, H G; Bertalot, L

    2012-10-01

    The neutron activation system (NAS) measures neutron fluence at the first wall and the total neutron flux from the ITER plasma, providing evaluation of the fusion power for all operational phases. The pneumatic transfer system (PTS) is one of the key components of the NAS for the proper operation of the system, playing a role of transferring encapsulated samples between the capsule loading machine, irradiation stations, counting stations, and disposal bin. For the validation and the optimization of the design, a prototype of the PTS was developed and capsule transfer tests were performed with the developed system.

  1. Control of pneumatic transfer system for neutron activation analysis

    International Nuclear Information System (INIS)

    Pneumatic transfer system(PTS) is one of the facilities to be used in irradiation of target materials for neutron activation analysis(NAA) in the research reactor. There are two systems the manual and the automatic system in PTS of HANARO research reactor. The pneumatic transfer system consists of many devices, sends and loads the capsules from NAA laboratory into three holes in the reflector tank of reactor and retrieves irradiated capsules after irradiation. This report describes the part's design, control system and the operation procedures. All the algorithm described in the text will be used for maintenance and upgrading

  2. Control of pneumatic transfer system for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H. S.; Chung, Y. S.; Wu, J. S.; Kim, H. K.; Choi, Y. S.; Kim, S. H.; Moon, J. H.; Baek, S. Y

    2000-06-01

    Pneumatic transfer system(PTS) is one of the facilities to be used in irradiation of target materials for neutron activation analysis(NAA) in the research reactor. There are two systems the manual and the automatic system in PTS of HANARO research reactor. The pneumatic transfer system consists of many devices, sends and loads the capsules from NAA laboratory into three holes in the reflector tank of reactor and retrieves irradiated capsules after irradiation. This report describes the part's design, control system and the operation procedures. All the algorithm described in the text will be used for maintenance and upgrading.

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

    International Nuclear Information System (INIS)

    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

  4. Miniature neutron source reactor burnup calculations using IRBURN code system

    International Nuclear Information System (INIS)

    Highlights: ► Fuel consumption of Iranian MNSR during 15 years of operation has been investigated. ► Calculations have been performed by the IRBURN code. Precision and accuracy of the implemented model has been validated. ► Our study shows the consumption rate of MNSR is about 1%. - Abstract: Fuel consumption of Iranian miniature neutron source reactor (MNSR) during 15 years of operation has been investigated. Reactor core neutronic parameters such as flux and power distributions, control rod worth and effective multiplication factor at BOL and after 15 years of irradiation has been calculated. The Monte Carlo-based depletion code system IRBURN has been used for studying the reactor core neutronic parameters as well as the isotopic inventory of the fuel during burnup. The precision and accuracy of the implemented model has been verified via validation the results for neutronic parameters in the MNSR final safety analysis report. The results show that keff decreases from 1.0034 to 0.9897 and the total U-235 consumption in the core is about 13.669 g after 15 years of operational time. Finally, our studying shows the consumption rate of MNSR is about 1%.

  5. Gamma scintillator system using boron carbide for neutron detection

    International Nuclear Information System (INIS)

    A new approach for neutron detection enhancement to scintillator gamma-ray detectors is suggested. By using a scintillator coupled with a boron carbide (B4C) disc, the 478 keV gamma-photon emitted from the excited Li in 94% of the 10B(n,α)7Li interactions was detected. This suggests that the performance of existing gamma detection systems in Homeland security applications can be improved. In this study, a B4C disc (2 in. diameter, 0.125 in. thick) with ∼19.8% 10B was used and coupled with a scintillator gamma-ray detector. In addition, the neutron thermalization moderator was studied in order to be able to increase the neutron sensitivity. An improvement in the detector which is easy to assemble, affordable and efficient was demonstrated. Furthermore, a tailored Monte-Carlo code written in MATLAB was developed for validation of the proposed application through efficiency estimation for thermal neutrons. Validation of the code was accomplished by showing that the MATLAB code results were well correlated to a Monte-Carlo MCNP code results. The measured efficiency of the assembled experimental model was observed to be in agreement with both models calculations

  6. Neutron Transport Methods for Accelerator-Driven Systems

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas Tsoulfanidis; Elmer Lewis

    2005-02-09

    The objective of this project has been to develop computational methods that will enable more effective analysis of Accelerator Driven Systems (ADS). The work is centered at the University of Missouri at Rolla, with a subcontract at Northwestern University, and close cooperation with the Nuclear Engineering Division at Argonne National Laboratory. The work has fallen into three categories. First, the treatment of the source for neutrons originating from the spallation target which drives the neutronics calculations of the ADS. Second, the generalization of the nodal variational method to treat the R-Z geometry configurations frequently needed for scoping calculations in Accelerator Driven Systems. Third, the treatment of void regions within variational nodal methods as needed to treat the accelerator beam tube.

  7. Development of neutron personnel monitoring system based on CR-39 solid state nuclear track detector

    International Nuclear Information System (INIS)

    Personnel neutron monitoring aims at providing a method to evaluate the magnitude of the detrimental effects on the personnel exposed to neutrons. Neutron monitoring is done for a small though growing number of personnel working with neutrons in a wide range of situations. Over the years, many solid state nuclear track detectors (SSNTD) have been tried for neutron personnel monitoring. CR-39 SSNTD is a proton sensitive polymer and offers a lot of promise for neutron personnel monitoring due to its high sensitivity and lower energy threshold for neutron detection. This report presents the mechanism of track formation in this polymer, the development of this neutron personnel monitoring system in our laboratory, its various characteristics and its promise as a routine personnel neutron monitor. (author). 1 tab., 7 figs

  8. Conceptual design of a camera system for neutron imaging in low fusion power tokamaks

    International Nuclear Information System (INIS)

    The basic principles for designing a camera system for neutron imaging in low fusion power tokamaks are illustrated for the case of the HL-2A tokamak device. HL-2A has an approximately circular cross section, with total neutron yields of about 1012 n/s under 1 MW neutral beam injection (NBI) heating. The accuracy in determining the width of the neutron emission profile and the plasma vertical position are chosen as relevant parameters for design optimization. Typical neutron emission profiles and neutron energy spectra are calculated by Monte Carlo method. A reference design is assumed, for which the direct and scattered neutron fluences are assessed and the neutron count profile of the neutron camera is obtained. Three other designs are presented for comparison. The reference design is found to have the best performance for assessing the width of peaked to broadened neutron emission profiles. It also performs well for the assessment of the vertical position

  9. Single neutron star systems evolving with fallback discs

    Science.gov (United States)

    Ertan, Unal; Caliskan, Sirin; Alpar, Mehmet Ali; Benli, Onur; Trümper, Joachim E.

    2016-07-01

    We have investigated the long-term evolution of the young neutron star systems, namely anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs), dim isolated neutron stars (XDINs), and the so-called "high-B radio pulsars" in the frame of the fallback disk disc model. We have shown that the X-ray luminosities and the rotational properties of individual sources in these different populations can be achieved by neutron stars evolving with fallback disks and with conventional dipole magnetic fields of young neutron stars. Presence of small-scale magnetar fields in the higher multi-poles which are likely to be responsible for soft gamma bursts observed from these systems is compatible with the fallback disk model, since the rotational evolution of the star is governed by the interaction between the large-scale dipole field and the disc. The results of our model is self-consistent in that (1) the X-ray luminosity, period and period derivative of individual sources are produced simultaneously, and (2) these results are obtained with very similar set of main disk parameters for all these systems with rather different properties. Our results indicate that all known AXPs, except two sources, are in the accretion phase at present. The 6 XDINs with confirmed period and period derivatives reached their long periods in the accretion epochs in the past. At present, XDINs are evolving in the propeller phase without accretion, but they are still slowing down under effect of the disk torques. For the "high-B radio pulsars", the source properties are obtained in the phases when accretion is not allowed, which is consistent with the radio pulsar property of these sources.

  10. Ultra-stripped supernovae and double neutron star systems

    CERN Document Server

    Tauris, Thomas

    2015-01-01

    The evolution of close-orbit progenitor binaries of double neutron star (DNS) systems leads to supernova (SN) explosions of ultra-stripped stars. The amount of SN ejecta mass is very limited from such, more or less, naked metal cores with envelope masses of only 0.01-0.2 Msun. The combination of little SN ejecta mass and the associated possibility of small NS kicks is quite important for the characteristics of the resulting DNS systems left behind. Here, we discuss theoretical predictions for DNS systems, based on Case BB Roche-lobe overflow prior to ultra-stripped SNe, and briefly compare with observations.

  11. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis

  12. Monitoring of D-T accelerator neutron output in a PGNAA system using silicon carbide detectors

    Science.gov (United States)

    Dulloo, Abdul R.; Ruddy, Frank H.; Seidel, John G.; Petrović, Bojan

    2001-07-01

    Silicon carbide (SiC) detectors are being employed to monitor the neutron output of the D-T accelerator in a pulsed Prompt Gamma Neutron Activation Analysis (PGNAA) system. Detection of the source neutrons relies on energetic neutron reactions in the detector material. Experimental testing has been performed to confirm that the detector response is caused by fast neutrons from the accelerator source. Modeling calculations have also been carried out to provide additional verification. Use of the SiC detectors in the PGNAA system is expected to assist in evaluating system performance as well as ensuring accurate data interpretation and analysis.

  13. Magnetic systems for wide-aperture neutron polarizers and analyzers

    Science.gov (United States)

    Gilev, A. G.; Pleshanov, N. K.; Bazarov, B. A.; Bulkin, A. P.; Schebetov, A. F.; Syromyatnikov, V. G.; Tarnavich, V. V.; Ulyanov, V. A.

    2016-10-01

    Requirements on the field uniformity in neutron polarizers are analyzed in view of the fact that neutron polarizing coatings have been improved during the past decade. The design of magnetic systems that meet new requirements is optimized by numerical simulations. Magnetic systems for wide-aperture multichannel polarizers and analyzers are represented, including (a) the polarizer to be built at channel 4-4‧ of the reactor PIK (Gatchina, Russia) for high-flux experiments with a 100×150 mm2 beam of polarized cold neutrons; (b) the fan analyzer covering a 150×100 mm2 window of the detector at the Magnetism Reflectometer (SNS, ORNL, USA); (c) the polarizer and (d) the fan analyzer covering a 220×110 mm2 window of the detector at the reflectometer NERO, which is transferred to PNPI (Russia) from HZG (Germany). Deviations of the field from the vertical did not exceed 2°. The polarizing efficiency of the analyzer at the Magnetism Reflectometer reached 99%, a record level for wide-aperture supermirror analyzers.

  14. A new compact, high sensitivity neutron imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Caillaud, T.; Landoas, O.; Briat, M.; Rosse, B.; Thfoin, I.; Philippe, F.; Casner, A.; Bourgade, J. L.; Disdier, L. [CEA, DAM, DIF,F-91297 Arpajon (France); Glebov, V. Yu.; Marshall, F. J.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Park, H. S.; Robey, H. F.; Amendt, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2012-10-15

    We have developed a new small neutron imaging system (SNIS) diagnostic for the OMEGA laser facility. The SNIS uses a penumbral coded aperture and has been designed to record images from low yield (10{sup 9}-10{sup 10} neutrons) implosions such as those using deuterium as the fuel. This camera was tested at OMEGA in 2009 on a rugby hohlraum energetics experiment where it recorded an image at a yield of 1.4 Multiplication-Sign 10{sup 10}. The resolution of this image was 54 {mu}m and the camera was located only 4 meters from target chamber centre. We recently improved the instrument by adding a cooled CCD camera. The sensitivity of the new camera has been fully characterized using a linear accelerator and a {sup 60}Co {gamma}-ray source. The calibration showed that the signal-to-noise ratio could be improved by using raw binning detection.

  15. A high power accelerator driver system for spallation neutron sources

    International Nuclear Information System (INIS)

    This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). For several years, the Los Alamos Meson Physics Facility (LAMPF) and the Proton Storage Ring (PSR) have provided a successful driver for the nearly 100-kW Los Alamos Neutron Scattering Center (LANSCE) source. The authors have studied an upgrade to this system. The goal of this effort was to establish a credible design for the accelerator driver of a next-generation source providing 1-MW of beam power. They have explored a limited subset of the possible approaches to a driver and have considered only the low 1-MW beam power. The next-generation source must utilize the optimum technology and may require larger neutron intensities than they now envision

  16. Application of neutron activation analysis system in Xi'an pulsed reactor

    CERN Document Server

    Zhang Wen Shou; Yu Qi

    2002-01-01

    Neutron Activation Analysis System in Xi'an Pulsed Reactor is consist of rabbit fast radiation system and experiment measurement system. The functions of neutron activation analysis are introduced. Based on the radiation system. A set of automatic data handling and experiment simulating system are built. The reliability of data handling and experiment simulating system had been verified by experiment

  17. Coupling CFD code with system code and neutron kinetic code

    International Nuclear Information System (INIS)

    Highlights: • Coupling interface between CFD code Fluent and system code Athlet was created. • Athlet code is internally coupled with neutron kinetic code Dyn3D. • Explicit coupling of overlapped computational domains was used. • A coupled system of Athlet/Dyn3D+Fluent codes was successfully tested on a real case. - Abstract: The aim of this work was to develop the coupling interface between CFD code Fluent and system code Athlet internally coupled with neutron kinetic code Dyn3D. The coupling interface is intended for simulation of complex transients such as Main Steam Line Break scenarios, which cannot be modeled separately first by system and neutron kinetic code and then by CFD code, because of the feedback between the codes. In the first part of this article, the coupling method is described. Explicit coupling of overlapped computational domains is used in this work. The second part of the article presents a demonstration simulation performed by the coupled system of Athlet/Dyn3D and Fluent. The “Opening a Steam Dump to the Atmosphere” test carried out at the Temelin NPP (VVER-1000) was simulated by the coupled system. In this simulation, the primary and secondary circuits were modeled by Athlet, mixing in downcomer and lower plenum was simulated by Fluent and heat generation in the core was calculated by Dyn3D. The results of the simulation with Athlet/Dyn3D+Fluent were compared with the experimental data and the results from a calculation performed with Athlet/Dyn3D without Fluent

  18. CASCADE - a multi-layer Boron-10 neutron detection system

    CERN Document Server

    Köhli, M; Allmendinger, F; Perrevoort, A -K; Schröder, T; Martin, N; Schmidt, C J; Schmidt, U

    2016-01-01

    The globally increased demand for helium-3 along with the limited availability of this gas calls for the development of alternative technologies for the large ESS instrumentation pool. We report on the CASCADE Project - a novel detection system, which has been developed for the purposes of neutron spin echo spectroscopy. It features 2D spatially resolved detection of thermal neutrons at high rates. The CASCADE detector is composed of a stack of solid boron-10 coated Gas Electron Multiplier foils, which serve both as a neutron converter and as an amplifier for the primary ionization deposited in the standard Argon-CO2 counting gas environment. This multi-layer setup efficiently increases the detection efficiency and serves as a helium-3 alternative. It has furthermore been possible to extract the signal of the charge traversing the stack to identify the very thin conversion layer of about 1 micrometer. This allows the precise determination of the time-of-flight, necessary for the application in MIEZE spin echo...

  19. Solution of thermal neutron diffusion equation for the two-component system by perturbation calculation

    International Nuclear Information System (INIS)

    A method of solving the diffusion equation for the th ermal neutron flux in a heterogeneous medium is presented. Perturbation calculation is successfully applied for the cylindrical concentric system after testing this method for the spherical concentric geometry analytically solved by Czubek (1981). The method permits to calculate the t hermal neutron decay constant and the space distribution of the thermal neutron flux in a heterogeneous geom etry. The condition of the constant value of the neutron flux in the inner part of the system has to be m et. This method has an application in the measurement of the thermal neutron absorption cross section, presented by Czubek (1981). (author)

  20. Evaluation of the NDP (neutron diagnostic probe) system

    Energy Technology Data Exchange (ETDEWEB)

    Pentaleri, E.A.; Eisen, Y.Y.

    1990-12-01

    The neutron diagnostic probe (NDP), an explosive detection system developed by Consolidated Controls Corporation and based on the associated-alpha-particle technique, was evaluated. Although many problems were found with the prototype system that make it useless for most practical applications, the NDP system may be considered a successful proof-of-principle for the basic explosive detection system design. In addition to evaluating the design and performance of the present system, models were developed to estimate the performance that might reasonably be expected from full scale systems of different conceptual design. Specific examples involved various types of bulk and sheet explosives contained in a suitcase and a large crate. Also considered were the effects of innocuous materials surrounding explosives in different scenarios, including the deliberate use of shielding materials as a countermeasure to detection. 11 refs., 46 figs., 24 tabs.

  1. Count-loss effect in subcriticality measurement by pulsed neutron source method. (2) Proposal for utilization of neutron detection system operated in current mode

    International Nuclear Information System (INIS)

    It was pointed out in the previous paper that the neutron decay constant determined by the pulsed neutron source method that employs the neutron detection system operated in the pulse mode is expected to be biased owing to the count-loss effect even when the intensity of pulsed neutron source is not high. To avoid this difficulty, by paying attention to the current mode that is inherently free from the count-loss process, the pulsed neutron source method with neutron detection system operated in the current mode was proposed. Using this method, not only the neutron decay constant but also the absolute value of subcriticality are obtained when a proper time constant of neutron detection system is selected. (author)

  2. Transport calculation of thermal and cold neutrons using NMTC/JAERI-MCNP4A code system

    Energy Technology Data Exchange (ETDEWEB)

    Iga, Kiminori [Kyushu Univ., Fukuoka (Japan); Takada, Hiroshi; Nagao, Tadashi

    1998-01-01

    In order to investigate the applicability of the NMTC/JAERI-MCNP4A code system to the neutronics design study in the neutron science research project of JAERI, transport calculations of thermal and cold neutrons are performed with the code system on a spallation neutron source composed of light water cooled tantalum target with a moderator and a reflector system. The following neutronic characteristics are studied in the calculation : the variation of the intensity of neutrons emitted from a light water moderator or a liquid hydrogen with/without the B{sub 4}C decoupler, which are installed to produce sharp pulse, and that dependent on the position of external source neutrons in the tantalum target. The calculated neutron energy spectra are reproduced well by the semi-empirical formula with the parameter values reliable in physical meanings. It is found to be necessary to employ proper importance sampling technique in the statistics. It is confirmed from this work that the NMTC/JAERI-MCNP4A code system is applicable to the neutronics design study of spallation neutron sources proposed for the neutron science research project. (author)

  3. Modeling Mergers of Known Galactic Systems of Binary Neutron Stars

    CERN Document Server

    Feo, Alessandra; Maione, Francesco; Löffler, Frank

    2016-01-01

    We present a study of the merger of six different known galactic systems of binary neutron stars (BNS) of unequal mass with a mass ratio between $0.75$ and $0.99$. Specifically, these systems are J1756-2251, J0737-3039A, J1906+0746, B1534+12, J0453+1559 and B1913+16. We follow the dynamics of the merger from the late stage of the inspiral process up to $\\sim$ 20 ms after the system has merged, either to form a hyper-massive neutron star (NS) or a rotating black hole (BH), using a semi-realistic equation of state (EOS), namely the seven-segment piece-wise polytropic SLy with a thermal component. For the most extreme of these systems ($q=0.75$, J0453+1559), we also investigate the effects of different EOSs: APR4, H4, and MS1. Our numerical simulations are performed using only publicly available open source code such as, the Einstein Toolkit code deployed for the dynamical evolution and the LORENE code for the generation of the initial models. We show results on the gravitational wave signals, spectrogram and fr...

  4. Prompt gamma-ray neutron activation analysis (PGNAA) system by using a 740 GBq 241Am-Be neutron source

    International Nuclear Information System (INIS)

    A PGNAA system consisting of a 740 GBq 241Am-Be neutron source and a gamma spectrometer with a n-type Ge (REGe) detector was installed at Ankara Nuclear Training and Research Center to measure the prompt gamma-rays produced by the interactions of thermal neutrons in the samples for the analysis of light elements such as B, P, S and Cl, and some trace elements with large cross sections (Cd, Hg, Sm, Gd, etc.). In the irradiation system, a 55 cm diameter cylinder tank filled with the water moderator comprises the neutron source placed in a polypropylene tube that was positioned in lead rings (internal diameter - 9 cm and outer diameter - 21 cm) in order to reduce the gamma rays emitted from the source such as 0.0596 MeV (241Am) and 4.43 MeV (0.6 gamma per neutron) from the 9Be(α, n) reaction in the source. The moderator tank was shielded with paraffin in all sides against fast neutrons. The thickness of paraffin at the front side of the tank is 28 cm and 18 cm at other sides. The neutron irradiation system was also shielded by using chevron lead bricks of 18 cm thickness. The background-prominent gamma-rays which is especially the 2.223 MeV gamma ray from the 1H(n, γ) reaction formed in hydrogenous materials used for neutron moderation was reduced remarkably in view of the permissible gamma dose for overall irradiation room. The neutrons thermalized in moderator travel through the hole with 6 cm diameter for the sample irradiation. The detector was shielded with Li2CO3 powder against thermal neutrons to avoid radiation damage and surrounded by additional lead bricks to reduce gamma-background. The measurements are carried out for efficiency calibration of the detector by using the standard source. The characteristics of PGNAA system with the isotopic neutron source and its analysis capability are discussed

  5. The LANSCE (Los Alamos Neutron Scattering Center) target system

    International Nuclear Information System (INIS)

    During the summer of 1985, we replaced the WNR T-shaped target/moderator scheme with the LANSCE split-target/flux-trap-moderator design. The intent of this 'LANSCE upgrade' was to increase (to 12) the number of neutron beam lines serviced simultaneously, and to enhance the target area shielding and target system to accept 200 μA of 800-MeV protons. The four LANSCE moderators consist of three (chilled) water moderators, and a liquid hydrogen (20 K) moderator. The LANSCE target is machinable tungsten

  6. Portable system for periodical verification of area monitors for neutrons; Sistema portatil para verificacao periodica de monitores de area para neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Luciane de R.; Leite, Sandro Passos; Lopes, Ricardo Tadeu, E-mail: rluciane@ird.gov.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Energia Nuclear; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da; Pereira, Walsan W., E-mail: karla@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiacoes Ionizantes (LNMRI). Lab. de Neutrons

    2009-07-01

    The Neutrons Laboratory develops a project viewing the construction of a portable test system for verification of functioning conditions of neutron area monitors. This device will allow to the users the verification of the calibration maintenance of his instruments at the use installations, avoiding the use of an inadequate equipment related to his answer to the neutron beam response

  7. Analyzing the effect of geometric factors on designing neutron radiography system.

    Science.gov (United States)

    Amini, Moharam; Fadaei, Amir Hosein; Gharib, Morteza

    2015-11-01

    Neutron radiography is one of the main applications of research reactors. It is a powerful tool to conduct nondestructive testing of materials. The parameters that affect the quality of a radiographic image must be considered during the design of a neutron radiography system. Hence, this study aims to investigate the effect of geometric factors on the quality of the neutron radiography system. The results show that the performance of the mentioned system can be increased by regulating the geometric factors. PMID:26343340

  8. Neutron Radiography

    OpenAIRE

    Reddy, A. R.; Rao, M. V. N.

    2012-01-01

    The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  9. Neutron Interrogation System For Underwater Threat Detection And Identification

    Science.gov (United States)

    Barzilov, Alexander P.; Novikov, Ivan S.; Womble, Phil C.

    2009-03-01

    Wartime and terrorist activities, training and munitions testing, dumping and accidents have generated significant munitions contamination in the coastal and inland waters in the United States and abroad. Although current methods provide information about the existence of the anomaly (for instance, metal objects) in the sea bottom, they fail to identify the nature of the found objects. Field experience indicates that often in excess of 90% of objects excavated during the course of munitions clean up are found to be non-hazardous items (false alarm). The technology to detect and identify waterborne or underwater threats is also vital for protection of critical infrastructures (ports, dams, locks, refineries, and LNG/LPG). We are proposing a compact neutron interrogation system, which will be used to confirm possible threats by determining the chemical composition of the suspicious underwater object. The system consists of an electronic d-T 14-MeV neutron generator, a gamma detector to detect the gamma signal from the irradiated object and a data acquisition system. The detected signal then is analyzed to quantify the chemical elements of interest and to identify explosives or chemical warfare agents.

  10. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.

    Science.gov (United States)

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively. PMID:26595774

  11. System of adjoint P1 equations for neutron moderation

    International Nuclear Information System (INIS)

    In some applications of perturbation theory, it is necessary know the adjoint neutron flux, which is obtained by the solution of adjoint neutron diffusion equation. However, the multigroup constants used for this are weighted in only the direct neutron flux, from the solution of direct P1 equations. In this work, this procedure is questioned and the adjoint P1 equations are derived by the neutron transport equation, the reversion operators rules and analogies between direct and adjoint parameters. (author)

  12. The monitoring system of a high performance fusion neutron spectrometer

    CERN Document Server

    Tardocchi, M; Ericsson, G; Frenje, J; Kaellne, J; Traneus, E

    2002-01-01

    Neutron emission spectroscopy (NES) diagnosis of high-power fusion plasma has been performed with the magnetic proton recoil (MPR) spectrometer installed at the Joint European Torus tokamak. The MPR is a high performance instrument where the setting of working points to prescribed calibration values is essential. This includes the MPR focal plane detector whose photomultipliers must be monitored for gain stability with respect to short- and long-term drifts as well as transient changes. A special monitoring system was developed for the MPR including a light pulser in the form of light emitting diodes. The monitoring system as part of the MPR focal plane detector is described here as well as the monitoring procedures and applications. Results from the use of the monitoring system are presented illustrating its present capabilities and possibilities for further developments in next step NES diagnostics.

  13. Neutronic analysis of the 1D and 1E banks reflux detection system

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, A.

    1999-12-21

    Two H Canyon neutron monitoring systems for early detection of postulated abnormal reflux conditions in the Second Uranium Cycle 1E and 1D Mixer-Settle Banks have been designed and built. Monte Carlo neutron transport simulations using the general purpose, general geometry, n-particle MCNP code have been performed to model expected response of the monitoring systems to varying conditions.The confirmatory studies documented herein conclude that the 1E and 1D neutron monitoring systems are able to achieve adequate neutron count rates for various neutron source and detector configurations, thereby eliminating excessive integration count time. Neutron count rate sensitivity studies are also performed. Conversely, the transport studies concluded that the neutron count rates are statistically insensitive to nitric acid content in the aqueous region and to the transition region length. These studies conclude that the 1E and 1D neutron monitoring systems are able to predict the postulated reflux conditions for all examined perturbations in the neutron source and detector configurations. In the cases examined, the relative change in the neutron count rates due to postulated transitions from normal {sup 235}U concentration levels to reflux levels remain satisfactory detectable.

  14. Optic fibber data acquisition and transmission system dedicated to a neutron generator

    International Nuclear Information System (INIS)

    Hereby, are presented the design, construction and application of a virtual data acquisition system based on the usage of microcontrollers, optic fibber, and PC. System is aimed to the reestablishment of the communication between the basic modules of a Neutron Generator. The work shows, how the original interface design is upgraded by the automation of the data acquisition, on the Neutron Generator exploitation parameters. The PC usage is being introduced in the Neutron Generator and the precedent is established for further subsystem

  15. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis

    International Nuclear Information System (INIS)

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of 252Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5).

  16. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility

    International Nuclear Information System (INIS)

    The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of 252Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from 252Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom

  17. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis.

    Science.gov (United States)

    Ghassoun, J; Mostacci, D

    2011-08-01

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of (252)Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5). PMID:21129990

  18. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J. [EPRA, Departement de Physique, Faculte des Sciences Semlalia, B.P. 2390, 40000 Marrakech (Morocco)], E-mail: ghassoun@ucam.ac.ma; Chkillou, B.; Jehouani, A. [EPRA, Departement de Physique, Faculte des Sciences Semlalia, B.P. 2390, 40000 Marrakech (Morocco)

    2009-04-15

    The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of {sup 252}Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from {sup 252}Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom.

  19. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ghassoun, J., E-mail: ghassoun@ucam.ac.ma [EPRA, Department of Physics, Faculty of Sciences, Semlalia, P.O. Box 2390, 40000 Marrakech (Morocco); Mostacci, D., E-mail: domiziano.mostacci@mail.ing.unibo.it [University of Bologna, Montecuccolino Laboratory, via dei Colli 16, I-40136 Bologna (Italy)

    2011-08-15

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of {sup 252}Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5).

  20. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility.

    Science.gov (United States)

    Ghassoun, J; Chkillou, B; Jehouani, A

    2009-04-01

    The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of (252)Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from (252)Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom. PMID:19168369

  1. Compact turnkey focussing neutron guide system for inelastic scattering investigations

    Energy Technology Data Exchange (ETDEWEB)

    Brandl, G., E-mail: g.brandl@fz-juelich.de [Heinz Maier-Leibnitz Zentrum (MLZ) and Physik Department E21, Technische Universität München, 85748 Garching, Germany and Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum - MLZ, Forschungszentrum Jülich GmbH, 85748 Garching (Germany); Georgii, R. [Heinz Maier-Leibnitz Zentrum (MLZ) and Physik Department E21, Technische Universität München, 85748 Garching (Germany); Dunsiger, S. R. [Physik Department E21, Technische Universität München, 85748 Garching, Germany and Center for Emergent Materials, Ohio State University, Columbus, Ohio 43210-1117 (United States); Tsurkan, V. [Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86159 Augsburg, Germany and Institute of Applied Physics, Academy of Sciences of Moldova, MD 2028 Chisinau, Republic of Moldova (Germany); Loidl, A. [Experimental Physics V, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86159 Augsburg (Germany); Adams, T.; Pfleiderer, C.; Böni, P. [Physik Department E21, Technische Universität München, 85748 Garching (Germany)

    2015-12-21

    We demonstrate the performance of a compact neutron guide module which boosts the intensity in inelastic neutron scattering experiments by approximately a factor of 40. The module consists of two housings containing truly curved elliptic focussing guide elements, positioned before and after the sample. The advantage of the module lies in the ease with which it may be reproducibly mounted on a spectrometer within a few hours, on the same timescale as conventional sample environments. It is particularly well suited for samples with a volume of a few mm{sup 3}, thus enabling the investigation of materials which to date would have been considered prohibitively small or samples exposed to extreme environments, where there are space constraints. We benchmark the excellent performance of the module by measurements of the structural and magnetic excitations in single crystals of model systems. In particular, we report the phonon dispersion in the simple element lead. We also determine the magnon dispersion in the spinel ZnCr{sub 2}Se{sub 4} (V = 12.5 mm{sup 3}), where strong magnetic diffuse scattering at low temperatures evolves into distinct helical order.

  2. Comptonization and QPO Origins in Accreting Neutron Star Systems

    CERN Document Server

    Lee, H C; Lee, Hyong C.; Miller, Guy S.

    1997-01-01

    We develop a simple, time-dependent Comptonization model to probe the origins of spectral variability in accreting neutron star systems. In the model, soft ``seed photons'' are injected into a corona of hot electrons, where they are Compton upscattered before escaping as hard X-rays. The model describes how the hard X-ray spectrum varies when the properties of either the soft photon source or the Comptonizing medium undergo small oscillations. Observations of the resulting spectral modulations can determine whether the variability is due to (i) oscillations in the injection of seed photons, (ii) oscillations in the coronal electron density, or (iii) oscillations in the coronal energy dissipation rate. Identifying the origin of spectral variability should help clarify how the corona operates and its relation to the accretion disk. It will also help in finding the mechanisms underlying the various quasi-periodic oscillations (QPO) observed in the X-ray outputs of many accreting neutron star and black hole syste...

  3. The neutron distribution system of the new ultra-cold neutron source at the FRM II

    Energy Technology Data Exchange (ETDEWEB)

    Wlokka, Stephan; Frei, Andreas [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Techische Universitaet Muenchen, Lichtenbergstrasse 1, D-85747 Garching (Germany); Fierlinger, Peter; Paul, Stephan [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse 1, D-85748 Garching (Germany); Geltenbort, Peter [Institut Laue-Langevin, BP 156, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2013-07-01

    Ultra-cold neutrons (UCN) are neutrons which are totally reflected from a given material surface. Typical energies of UCN are below 300 neV and velocities below 8 m/s. Thus they can be stored in material or magnetic bottles for several hundreds of seconds. As such, UCN are excellent laboratories to study fundamental parameters, e.g. the free neutron lifetime or the electric dipole moment of the neutron. The new UCN source foreseen at the FRM II will deliver high UCN densities to four experimental areas. Hence a mechanism to distribute as many UCN as possible to these areas is needed. We have developed a high efficiency UCN switch for this purpose. This talk reports about a series of measurements conducted with this switch. There have been three types of measurements, testing the transmission, storage and surface properties of the switch.

  4. Stability evaluation and correction of a pulsed neutron generator prompt gamma activation analysis system

    International Nuclear Information System (INIS)

    Source output stability is important for accurate measurement in prompt gamma neutron activation. This is especially true when measuring low-concentration elements such as in vivo nitrogen (∼2.5 % of body weight). We evaluated the stability of the compact DT neutron generator within an in vivo nitrogen measurement system. Review of gamma event/time patterns and data from an auxiliary detector showed significant variations among repeated phantom runs. Neutron generator instability had a significant effect on measurement precision. The neutron generator used in our system must be monitored for output consistency. Adjustments must be made to measurement results to correct for generator instability. (author)

  5. High-yield neutron activation system for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, Cris W.; Murphy, Thomas J.; Oertel, John A.

    2001-01-01

    The most accurate absolutely calibrated measurement of the total yield of neutrons from experiments on the National Ignition Facility will be from activation of threshold nuclear reactions. The high-yield neutron activation system is being designed to provide high-accuracy (similar to the {+-}7% achieved on other fusion experiments) linear measurements over a 9-order-of-magnitude dynamic range from the facility limit of {approx}10{sup 19} neutrons/shot down to a minimum of {approx}3x10{sup 10} neutrons/shot. The system design requirements are presented, and a conceptual design to meet those requirements described.

  6. Detailed Design of Cooling Water System for Cold Neutron Source in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Soo; Choi, Jung Woon; Kim, Y. K.; Wu, S. I.; Lee, Y. S

    2007-04-15

    To make cold neutron, a cryogenic refrigerator is necessary to transform moderator into cryogenic state so, thermal neutron is changed into cold neutron through heat transfer with moderator. A cryogenic refrigerator mainly consists of two apparatus, a helium compressor and a cold box which needs supply of cooling water. Therefore, cooling water system is essential to operate of cryogenic refrigerator normally. This report is mainly focused on the detailed design of the cooling water system for the HANARO cold neutron source, and describes design requirement, calculation, specification of equipment and water treatment method.

  7. Neutron slowing-down time in finite water systems

    International Nuclear Information System (INIS)

    The influence of the size of a moderator system on the neutron slowing-down time has been investigated. The experimental part of the study was performed on six cubes of water with side lengths from 8 to 30 cm. Neutrons generated in pulses of about 1 ns width were slowed down from 14 MeV to 1.457 eV. The detection method used was based on registration of gamma radiation from the main capture resonance of indium. The most probable slowing-down times were found to be 778 +- 23 ns and 898 +- 25 ns for the smallest and for the largest cubes, respectively. The corresponding mean slowing-down times were 1205 +- 42 ns and 1311 +- 42 ns. In a separate measurement series the space dependence of the slowing-down time close to the source was studied. These experiments were supplemented by a theoretical calculation which gave an indication of the space dependence of the slowingdown time in finite systems. The experimental results were compared to the slowing-down times obtained from various theoretical approaches and from Monte Carlo calculations. All the methods show a decrease of the slowing-down time with decreasing size of the moderator. This effect was least pronounced in the experimental results, which can be explained by the fact the measurements are spatially dependent. The agreement between the Monte Carlo results and those obtained using the diffusion approximation or the age-diffusion theory is surprisingly good, especially for large systems. The P1 approximation, on the other hand, leads to an overestimation of the effect of the finite size on the slowing-down time. (author)

  8. Design and construction of a movement mechanical system for a shield detector of a neutron diffractometer

    International Nuclear Information System (INIS)

    We present the design parameters of the mechanical system for a shield movement detector of a neutron diffractometer and the calculations to determine the power required to produce the rotation. The movement of the detection system is an essential part in order to get neutron diffraction spectra of a crystal. (author)

  9. Development of five axis robotic system for an industrial neutron tomography imaging system

    International Nuclear Information System (INIS)

    Tomography is one of the latest techniques in the field of nondestructive testing. X-rays, gamma rays or neutrons are used as an energy source whereas five axis manipulator is designed to move the specimen across the beam. The 5 axis robotic system has been indigenously developed, designed, manufactured and tested to move up to 10 kg payload. Computer is necessary to process and store data and retrieve it for processing. The same computer is used for control of manipulator. Computer aided tomography is carried out for research and industrial use. Neutron beam will be used either for evaluation of organic materials in attenuation based measurements or for evaluation on the basis of neutron activation of materials like nuclear fuels. The paper describes the indigenously developed 5-axis robotic system as a part of a facility built around Kamini reactor at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. (author). 4 figs

  10. Hybridizing Gravitationl Waveforms of Inspiralling Binary Neutron Star Systems

    Science.gov (United States)

    Cullen, Torrey; LIGO Collaboration

    2016-03-01

    Gravitational waves are ripples in space and time and were predicted to be produced by astrophysical systems such as binary neutron stars by Albert Einstein. These are key targets for Laser Interferometer and Gravitational Wave Observatory (LIGO), which uses template waveforms to find weak signals. The simplified template models are known to break down at high frequency, so I wrote code that constructs hybrid waveforms from numerical simulations to accurately cover a large range of frequencies. These hybrid waveforms use Post Newtonian template models at low frequencies and numerical data from simulations at high frequencies. They are constructed by reading in existing Post Newtonian models with the same masses as simulated stars, reading in the numerical data from simulations, and finding the ideal frequency and alignment to ``stitch'' these waveforms together.

  11. A newly developed technique of wireless remote controlled visual inspection system for neutron guides of cold neutron research facilities at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Hyung; Cho, Yeong Garp; Kim, Jong In [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    KAERI developed a neutron guide system for cold neutron research facilities at HANARO from 2003 to 2010. In 2008, the old plug shutter and instruments were removed, and a new plug and primary shutter were installed as the first cold neutron delivery system at HANARO. At the beginning of 2010, all the neutron guides and accessories had been successfully installed as well. The neutron guide system of HANARO consists of the in pile plug assembly with in pile guides, the primary shutter with in shutter guides, the neutron guides in the guide shielding room with secondary shutter, and the neutron guides in the neutron guide hall. Three kinds of glass materials were selected with optimum lengths by considering their lifetime, shielding, maintainability and cost as well. Radiation damage of the guides can occur on the coating and glass by neutron capturing in the glass. It is a big challenge to inspect a guide failure because of the difficult surrounding environment, such as high level radiation, limited working space, and massive hard work for removing and reinstalling the shielding blocks as shown in Fig 1. Therefore, KAERI has developed a wireless remote controlled visual inspection system for neutron guides using an infrared light camera mounted on the vehicle moving in the guide.

  12. Optimization of a single sphere albedo system using 3He counters for the measurement of neutron dose equivalent rates and the field calibration of personnel albedo neutron dosimeters

    International Nuclear Information System (INIS)

    The laboratory type of an active single sphere albedo dosemeter system using three 3He proportional counters in a polyethylene sphere for the measurement of neutron dose equivalent rates and the field calibration of personnel neutron dosemeters was optimized with respect to the detector-moderator combination by means of calibration exposures. One detector is located in the centre of the sphere to measure the neutron dose equivalent rate and the other two detectors near the moderator surface, in order to simulate the response of the albedo neutron detector and the thermal neutron detector. The response of the detectors to neutrons in the range between thermal and 14 MeV neutrons was investigated for various moderator-absorber combinations. Comparison was made between the system response and the response of the passive detector system. After completion the active system could be used for comprehensive neutron field measurements in radiation protection. By means of a microprocessor the linear combination of the three detector readings gives energy independent readings of the neutron dose equivalent rate, the absorbed dose rate and the neutron flux density at particle accelerators and nuclear facilities. (orig./HP)

  13. Compounds for neutron radiation detectors and systems thereof

    Energy Technology Data Exchange (ETDEWEB)

    Payne, Stephen A.; Stoeffl, Wolfgang; Zaitseva, Natalia P.; Cherepy, Nerine J.; Carman, Leslie M.

    2016-08-30

    A composition of matter includes an organic molecule having a composition different than stilbene. The organic molecule is embodied as a crystal, and exhibits: an optical response signature for neutrons; an optical response signature for gamma rays, and performance comparable to or superior to stilbene in terms of distinguishing neutrons from gamma rays. The optical response signature for neutrons is different than the optical response signature for gamma rays.

  14. Development of a Neutron Spectroscopic System Utilizing Compressed Sensing Measurements

    OpenAIRE

    Vargas Danilo; Kurwitz R. Cable; Carron Igor; DePriest K. Russell

    2016-01-01

    A new approach to neutron detection capable of gathering spectroscopic information has been demonstrated. The approach relies on an asymmetrical arrangement of materials, geometry, and an ability to change the orientation of the detector with respect to the neutron field. Measurements are used to unfold the energy characteristics of the neutron field using a new theoretical framework of compressed sensing. Recent theoretical results show that the number of multiplexed samples can be lower tha...

  15. Layered shielding design for an active neutron interrogation system

    Science.gov (United States)

    Whetstone, Zachary D.; Kearfott, Kimberlee J.

    2016-08-01

    The use of source and detector shields in active neutron interrogation can improve detector signal. In simulations, a shielded detector with a source rotated π/3 rad relative to the opening decreased neutron flux roughly three orders of magnitude. Several realistic source and detector shield configurations were simulated. A layered design reduced neutron and secondary photon flux in the detector by approximately one order of magnitude for a deuterium-tritium source. The shield arrangement can be adapted for a portable, modular design.

  16. Formation of double neutron star systems as implied by observations

    Science.gov (United States)

    Beniamini, Paz; Piran, Tsvi

    2016-03-01

    Double Neutron Stars (DNS) have to survive two supernovae (SNe) and still remain bound. This sets strong limits on the nature of the second collapse in these systems. We consider the masses and orbital parameters of the DNS population and constrain the two distributions of mass ejection and kick velocities directly from observations with no a priori assumptions regarding evolutionary models and/or the types of the SNe involved. We show that there is strong evidence for two distinct types of SNe in these systems, where the second collapse in the majority of the observed systems involved small mass ejection (ΔM ≲ 0.5 M⊙) and a corresponding low-kick velocity (vk ≲ 30 km s-1). This formation scenario is compatible, for example, with an electron-capture SN. Only a minority of the systems have formed via the standard SN scenario involving larger mass ejection of ˜2.2 M⊙ and kick velocities of up to 400 km s-1. Due to the typically small kicks in most DNS (which are reflected by rather low proper motion), we predict that most of these systems reside close to the Galactic disc. In particular, this implies that more NS-NS mergers occur close to the Galactic plane. This may have non-trivial implications to the estimated merger rates of DNS and to the rate of LIGO/VIRGO detections.

  17. Detection System for Neutron $\\beta$ Decay Correlations in the UCNB and Nab experiments

    CERN Document Server

    Broussard, L J; Adamek, E R; Baeßler, S; Birge, N; Blatnik, M; Bowman, J D; Brandt, A E; Brown, M; Burkhart, J; Callahan, N B; Clayton, S M; Crawford, C; Cude-Woods, C; Currie, S; Dees, E B; Ding, X; Fomin, N; Frlez, E; Fry, J; Gray, F E; Hasan, S; Hickerson, K P; Hoagland, J; Holley, A T; Ito, T M; Klein, A; Li, H; Liu, C -Y; Makela, M F; McGaughey, P L; Mirabal-Martinez, J; Morris, C L; Ortiz, J D; Pattie, R W; Penttilä, S I; Plaster, B; Počanić, D; Ramsey, J C; Salas-Bacci, A; Salvat, D J; Saunders, A; Seestrom, S J; Sjue, S K L; Sprow, A P; Tang, Z; Vogelaar, R B; Vorndick, B; Wang, Z; Wei, W; Wexler, J; Wilburn, W S; Womack, T L; Young, A R

    2016-01-01

    We describe a detection system designed for precise measurements of angular correlations in neutron $\\beta$ decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for $\\beta$ electron detection with energy thresholds below 10 keV, energy resolution of $\\sim$3 keV FWHM, and rise time of $\\sim$50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of $\\beta$ particles and recoil protons from neutron $\\beta$ decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments, to determine the neutron $\\beta$ decay parameters $B$, $a$, and $b$.

  18. Development of neutron multiplication analysis method for a subcritical system by reaction rate distribution measurement

    International Nuclear Information System (INIS)

    Basic experiments for ADSR are performed in KUCA to study the nuclear characteristics for establishing a new neutron source for research. Usually, nuclear reactors are operated in a critical state. Even though they are operated in an subcritical state, they are a very close to the critical state, and there are no problems to use the effective multiplication factor keff to express the subcriticality, which is obtained by solving the homogeneous neutron balance equation without external source. However, ADSR are operated in a subcritical state, and experiments which are fairly far from critical state may be performed to investigate their nuclear properties. In subcritical systems, the neutron flux distribution produced by an external source depends on the energy and position of the external source, and then the multiplication rate fission neutrons and the effectiveness of the external source should depend on the position of the external source. However, the effective multiplication factor keff cannot take into account the influence of such an effect. For a subcritical system, the neutron multiplication which is defined as the ratio of the total neutrons produced in the system by either fission or external source to those produced by external source only, can be a good measure for the efficiency of the system to produce neutrons with a specific spectrum which is one of the final goals of the 'Neutron Factory' project. Unlike the theoretical neutron multiplication definition, based on one point reactor approximation which depends only on the subcriticality of the system, the method considered in this study takes into account the effect on the neutron source position and energy, which plays an important role in the level of neutron multiplication for a given subcritical system. In this study, the value of neutron multiplication will be evaluated by utilizing the reaction rate distribution of KUCA A-core experiment which is analyzed in a subcritical system combined with

  19. On the definition of neutron lifetimes in multiplying and non-multiplying systems

    International Nuclear Information System (INIS)

    Historically, the term neutron lifetime has been used in the literature to describe a wide variety of different time intervals associated with a neutron's trek through a given system. This duplication of usage of the term neutron lifetime has undoubtedly resulted in some confusion concerning its physical meaning. In hopes of reducing some of this confusion, we suggest in this work that the various time intervals characterizing the life of a neutron be divided into three general categories: (1) neutron lifespans, (2) reaction rate lifetimes, and (3) neutron generation times. In this report, we define these three different time intervals and give deterministic and Monte Carlo transport expressions that can be used to calculate them

  20. Low angle neutron data acquisition system for molecular biology

    International Nuclear Information System (INIS)

    The low angle spectrometer system utilizing a 2-dimensional position sensitive counter was designed to accommodate a variety of experiments in molecular biology requiring good low angle resolution. Biological structures requiring low angle analysis techniques fall into two groups: non-ordered systems (proteins or protein complexes in solution) and ordered systems with large spacings like muscle, collagen, and membranes. For structural investigations into such systems, data are ideally needed to a low scattering angle of 0.20 at 4.5 A or a minimum Q of 0.005 A-1 (Q = theta . 2π/lambda). Depending on the type of structure, data often extend to the high angle region, say 300. Apart from the low angle requirements, the spectrometer has to have good resolution to resolve diffraction peaks from samples with crystal spacings up to 1000 A or even larger. While it is desirable to build a spectrometer to such scattering conditions, given reactor conditions might not permit this and compromises have to be made between flux, resolution and lowest angle. The low angle spectrometer described here was designed to be used at the HFBR neutron beam pipe working at approximately 4.2 A or at the H4 satellite station working at 2.4 A

  1. Formation of Double Neutron Star systems as implied by observations

    CERN Document Server

    Beniamini, Paz

    2015-01-01

    Double Neutron Stars (DNS) have to survive two supernovae and still remain bound. This sets strong limits on the nature of the second collapse in these systems. We consider the masses and orbital parameters of the DNS population and constrain the two distributions of mass ejection and kick velocities directly from observations with no a-priori assumptions regarding evolutionary models and/or the types of the supernovae involved. We show that there is strong evidence for two distinct types of supernovae in these systems, where the second collapse in the majority of the observed systems involved small mass ejection ($\\Delta M\\lesssim 0.5M_{\\odot}$) and a corresponding low-kick velocity ($v_{k}\\lesssim 30 km/sec$). This formation scenario is compatible, for example, with an electron capture supernova. Only a minority of the systems have formed via the standard SN scenario involving larger mass ejection of $\\sim 2.2 M_{\\odot}$ and kick velocities of up to $400$km/sec. Due to the typically small kicks in most DNS ...

  2. Neutron sensors in the SP-100 reactor control system

    International Nuclear Information System (INIS)

    The reference reactor control approach for the mature generic flight system (GFS) utilizes highly reliable and diverse reactor outlet temperature measurements for control and protection. Although system dynamic analyses demonstrated that this approach is satisfactory for various modes of operation (including transients involving failure or degradation of equipment), the use of a neutron monitoring system (NMS) for initial startup and for an early period of power operation has been studied to improve the performance of the reactor control design. Control strategies were developed, simulation analyses were produced, and stability margins were examined. In this updated control approach, the signals from the NMS are used for the initial startup, for restarts, for power range control, and for protection from overpower transients as long as reliable data is available from the NMS. The results show satisfactory performance for the updated controls. If the lifetime of the NMS is shorter than that of the flight system, the reactor control will revert to the reference control approach employing reactor outlet temperature measurements only

  3. Characterization of the Annular Core Research Reactor (ACRR) Neutron Radiography System Imaging Plane

    OpenAIRE

    Kaiser Krista; Chantel Nowlen K.; Russell DePriest K.

    2016-01-01

    The Annular Core Research Reactor (ACRR) at Sandia National Laboratories (SNL) is an epithermal pool-type research reactor licensed up to a thermal power of 2.4 MW. The ACRR facility has a neutron radiography facility that is used for imaging a wide range of items including reactor fuel and neutron generators. The ACRR neutron radiography system has four apertures (65:1, 125:1, 250:1, and 500:1) available to experimenters. The neutron flux and spectrum as well as the gamma dose rate were char...

  4. A neutron Albedo system with time rejection for landmine and IED detection

    Energy Technology Data Exchange (ETDEWEB)

    Kovaltchouk, V.D., E-mail: kovaltchoukv@bubbletech.ca [Bubble Technology Industries, Chalk River, Ontario (Canada); Andrews, H.R.; Clifford, E.T.H. [Bubble Technology Industries, Chalk River, Ontario (Canada); Faust, A.A. [Defense R and D Canada-Suffield, Medicine Hat, Alberta (Canada); Ing, H. [Bubble Technology Industries, Chalk River, Ontario (Canada); McFee, J.E. [Defense R and D Canada-Suffield, Medicine Hat, Alberta (Canada)

    2011-10-01

    A neutron Albedo system has been developed for imaging of buried landmines and improvised explosive devices (IEDs). It involves irradiating the ground with fast neutrons and subsequently detecting the thermalized neutrons that return. A scintillating {sup 6}Li loaded ZnS(Ag) screen with a sensitive area of 40 cmx40 cm is used as a thermal neutron detector. Scintillation light is captured by orthogonal arrays of wavelength-shifting fibers placed on either side of the scintillator surface and then transferred to X and Y multi-pixel PMTs. A timing circuit, used with pulsed neutron sources, records the time when a neutron detection takes place relative to an external synchronization pulse from the pulsed source. Experimental tests of the Albedo system performance have been done in a sand box with a {sup 252}Cf neutron source (no time gating) and with pulsed D-D (2.6 MeV) neutrons from the Defense R and D Ottawa Van de Graaff accelerator (with time gating). Information contained in the time evolution of the thermal neutron field provided improved detection capability and image reconstruction. The detector design is described and experimental results are discussed.

  5. Gain factors with the new supermirror guide system at the Budapest Neutron Centre

    CERN Document Server

    Rosta, L; Revay, Z

    2002-01-01

    In parallel with the installation of a cold-neutron source (CNS) at the 10-MW Budapest Research Reactor, the neutron-guide system has been redesigned and replaced by state of art neutron optical elements. Monte Carlo calculations have been used to determine the optimal conditions for the guide parameters. For the three cold-neutron beams nearly 100 m of new guides were installed; a great part is made of supermirrors. The new in-pile guide system and the individual shutters enable minimal losses at the starting sections. The out-of-pile part was optimized for the experimental stations. The neutron-flux measurements were compared with the simulated values. The combined effect of the CNS and the guide system yields a gain factor in the flux as high as 30-60. (orig.)

  6. Development of the radial neutron camera system for the HL-2A tokamak.

    Science.gov (United States)

    Zhang, Y P; Yang, J W; Liu, Yi; Fan, T S; Luo, X B; Yuan, G L; Zhang, P F; Xie, X F; Song, X Y; Chen, W; Ji, X Q; Li, X; Du, T F; Ge, L J; Fu, B Z; Isobe, M; Song, X M; Shi, Z B; Yang, Q W; Duan, X R

    2016-06-01

    A new radial neutron camera system has been developed and operated recently in the HL-2A tokamak to measure the spatial and time resolved 2.5 MeV D-D fusion neutron, enhancing the understanding of the energetic-ion physics. The camera mainly consists of a multichannel collimator, liquid-scintillation detectors, shielding systems, and a data acquisition system. Measurements of the D-D fusion neutrons using the camera have been successfully performed during the 2015 HL-2A experiment campaign. The measurements show that the distribution of the fusion neutrons in the HL-2A plasma has a peaked profile, suggesting that the neutral beam injection beam ions in the plasma have a peaked distribution. It also suggests that the neutrons are primarily produced from beam-target reactions in the plasma core region. The measurement results from the neutron camera are well consistent with the results of both a standard (235)U fission chamber and NUBEAM neutron calculations. In this paper, the new radial neutron camera system on HL-2A and the first experimental results are described. PMID:27370450

  7. Development of the radial neutron camera system for the HL-2A tokamak

    Science.gov (United States)

    Zhang, Y. P.; Yang, J. W.; Liu, Yi; Fan, T. S.; Luo, X. B.; Yuan, G. L.; Zhang, P. F.; Xie, X. F.; Song, X. Y.; Chen, W.; Ji, X. Q.; Li, X.; Du, T. F.; Ge, L. J.; Fu, B. Z.; Isobe, M.; Song, X. M.; Shi, Z. B.; Yang, Q. W.; Duan, X. R.

    2016-06-01

    A new radial neutron camera system has been developed and operated recently in the HL-2A tokamak to measure the spatial and time resolved 2.5 MeV D-D fusion neutron, enhancing the understanding of the energetic-ion physics. The camera mainly consists of a multichannel collimator, liquid-scintillation detectors, shielding systems, and a data acquisition system. Measurements of the D-D fusion neutrons using the camera have been successfully performed during the 2015 HL-2A experiment campaign. The measurements show that the distribution of the fusion neutrons in the HL-2A plasma has a peaked profile, suggesting that the neutral beam injection beam ions in the plasma have a peaked distribution. It also suggests that the neutrons are primarily produced from beam-target reactions in the plasma core region. The measurement results from the neutron camera are well consistent with the results of both a standard 235U fission chamber and NUBEAM neutron calculations. In this paper, the new radial neutron camera system on HL-2A and the first experimental results are described.

  8. Hot background” of the mobile inelastic neutron scattering system for soil carbon analysis

    Science.gov (United States)

    The problem of gamma spectrum peaks identification arises when conducting soil carbon (and other elements) analysis using the mobile inelastic neutron scattering (MINS) system. Some gamma spectrum peaks could be associated with radioisotopes appearing due to neutron activation of both the MINS syste...

  9. The development of the scanning system of the neutron radiography experimental equipment

    International Nuclear Information System (INIS)

    The neutron radiography experimental equipment includes: the detector, the scanning system, the shielding facility etc. It rotates or moves the sample and adjusts the mutual position of the neutron source, the sample and the detector, and so it improves the image quality. (authors)

  10. Development of the radial neutron camera system for the HL-2A tokamak.

    Science.gov (United States)

    Zhang, Y P; Yang, J W; Liu, Yi; Fan, T S; Luo, X B; Yuan, G L; Zhang, P F; Xie, X F; Song, X Y; Chen, W; Ji, X Q; Li, X; Du, T F; Ge, L J; Fu, B Z; Isobe, M; Song, X M; Shi, Z B; Yang, Q W; Duan, X R

    2016-06-01

    A new radial neutron camera system has been developed and operated recently in the HL-2A tokamak to measure the spatial and time resolved 2.5 MeV D-D fusion neutron, enhancing the understanding of the energetic-ion physics. The camera mainly consists of a multichannel collimator, liquid-scintillation detectors, shielding systems, and a data acquisition system. Measurements of the D-D fusion neutrons using the camera have been successfully performed during the 2015 HL-2A experiment campaign. The measurements show that the distribution of the fusion neutrons in the HL-2A plasma has a peaked profile, suggesting that the neutral beam injection beam ions in the plasma have a peaked distribution. It also suggests that the neutrons are primarily produced from beam-target reactions in the plasma core region. The measurement results from the neutron camera are well consistent with the results of both a standard (235)U fission chamber and NUBEAM neutron calculations. In this paper, the new radial neutron camera system on HL-2A and the first experimental results are described.

  11. Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency-Fusion Neutronics Source

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, K., E-mail: shinohara.koji@jaea.go.jp; Ochiai, K.; Sukegawa, A. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Ishii, K.; Kitajima, S. [Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Miyagi 980-8579 (Japan); Baba, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Sasao, M. [Organization for Research Initiatives and Development, Doshisha University, Kyoto 602-8580 (Japan)

    2014-11-15

    In order to increase the count rate capability of a neutron detection system as a whole, we propose a multi-stage neutron detection system. Experiments to test the effectiveness of this concept were carried out on Fusion Neutronics Source. Comparing four configurations of alignment, it was found that the influence of an anterior stage on a posterior stage was negligible for the pulse height distribution. The two-stage system using 25 mm thickness scintillator was about 1.65 times the count rate capability of a single detector system for d-D neutrons and was about 1.8 times the count rate capability for d-T neutrons. The results suggested that the concept of a multi-stage detection system will work in practice.

  12. Experimental study on anomalous neutron production in deuterium/solid system

    International Nuclear Information System (INIS)

    A series of experiments on both D2O electrolysis and thermal cycle of deuterium absorbed Ti Turnings has been designed to examine the anomalous phenomena in Deuterium/Solid System. A neutron detector containing 16 BF3 tubes with a detection limit of 0.38 n/s for two hour counting was used for electrolysis experiments. No neutron counting rate statistically higher than detection limit was observed from Fleischmann ampersand Pons type experiments. An HLNCC neutron detector equipped with 18 3He tubes and a JSR-11 shift register unit with a detection limit of 0.20 n/s for a two hour run was employed to study the neutron signals in D2 gas experiments. Different material pretreatments were selected to review the changes in frequency and size of the neutron burst production. Experiment sequence was deliberately designed to distinguish the neutron burst from fake signals, e.g. electronic noise pickup, the cosmic rays and other sources of environmental background. Ten batches of dry fusion samples were tested, among them, seven batches with neutron burst signals occurred roughly at the temperature from -100 degree centigrade to near room temperature. In the first four runs of a typical sample batch, seven neutron bursts were observed with neutron numbers from 15 to 482, which are 3 and 75 times, respectively, higher than the uncertainty of background. However, no bursts happened for H2 dummy samples running in-between and afterwards and for sample batch after certain runs

  13. Gamma–neutron imaging system utilizing pulse shape discrimination with CLYC

    International Nuclear Information System (INIS)

    Recently, RMD has investigated the use of CLYC (Cs2LiYCl6:Ce), a new and emerging scintillation material, in a gamma–neutron coded aperture imaging system based on RMD's commercial RadCamTM instrument. CLYC offers efficient thermal neutron detection, fast neutron detection capabilities, excellent pulse shape discrimination (PSD), and gamma-ray energy resolution as good as 4% at 662 keV. PSD improves the isolation of higher energy gammas from thermal neutron interactions (>3 MeV electron equivalent peak), compared to conventional pulse height techniques. The scintillation emission time in CLYC provides the basis for PSD; where neutron interactions result in a slower emission rise and decay components while gamma interactions result in a faster emission components. By creating a population plot based on the ratio of the decay tail compared to the total integral amplitude (PSD ratio), discrimination of gammas, thermal neutrons, and fast neutrons is possible. Previously, we characterized the CLYC-based RadCam system for imaging gammas and neutrons using a layered W-Cd coded aperture mask and employing only pulse height discrimination. In this paper, we present the latest results which investigate gamma-neutron imaging capabilities using PSD. An FPGA system is used to acquire the CLYC–PSPMT last dynode signals, determine a PSD ratio for each event, and compare it to a calibrated PSD cutoff. Each event is assigned either a gamma (low) or neutron (high) flag signal which is then correlated with the imaging information for each event. - Highlights: • The latest results are presented for our CLYC RadCam-2 system which investigate gamma–neutron imaging using pulse shape discrimination. • CLYC RadCam-2 system successfully discriminates gammas, thermal neutrons, and fast neutrons by employing a fully integrated, FPGA-based PSD system. • Imaging of our 252Cf source was possible using both pulse height and pulse shape discrimination with CLYC. • Imaging with

  14. Gamma–neutron imaging system utilizing pulse shape discrimination with CLYC

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, Chad M., E-mail: cwhitney@rmdinc.com; Soundara-Pandian, Lakshmi; Johnson, Erik B.; Vogel, Sam; Vinci, Bob; Squillante, Michael; Glodo, Jarek; Christian, James F.

    2015-06-01

    Recently, RMD has investigated the use of CLYC (Cs{sub 2}LiYCl{sub 6}:Ce), a new and emerging scintillation material, in a gamma–neutron coded aperture imaging system based on RMD's commercial RadCam{sup TM} instrument. CLYC offers efficient thermal neutron detection, fast neutron detection capabilities, excellent pulse shape discrimination (PSD), and gamma-ray energy resolution as good as 4% at 662 keV. PSD improves the isolation of higher energy gammas from thermal neutron interactions (>3 MeV electron equivalent peak), compared to conventional pulse height techniques. The scintillation emission time in CLYC provides the basis for PSD; where neutron interactions result in a slower emission rise and decay components while gamma interactions result in a faster emission components. By creating a population plot based on the ratio of the decay tail compared to the total integral amplitude (PSD ratio), discrimination of gammas, thermal neutrons, and fast neutrons is possible. Previously, we characterized the CLYC-based RadCam system for imaging gammas and neutrons using a layered W-Cd coded aperture mask and employing only pulse height discrimination. In this paper, we present the latest results which investigate gamma-neutron imaging capabilities using PSD. An FPGA system is used to acquire the CLYC–PSPMT last dynode signals, determine a PSD ratio for each event, and compare it to a calibrated PSD cutoff. Each event is assigned either a gamma (low) or neutron (high) flag signal which is then correlated with the imaging information for each event. - Highlights: • The latest results are presented for our CLYC RadCam-2 system which investigate gamma–neutron imaging using pulse shape discrimination. • CLYC RadCam-2 system successfully discriminates gammas, thermal neutrons, and fast neutrons by employing a fully integrated, FPGA-based PSD system. • Imaging of our {sup 252}Cf source was possible using both pulse height and pulse shape discrimination with

  15. Characterization of film-converter screens systems for neutron radiography; Caracterizacao de sistemas filme-conversor para radiografia com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marcos Leandro Garcia

    2002-07-01

    In general a good quality radiography is that one able to furnish high contrast and sharp edge images. Technically 'high contrast' means high capability to discern material thickness and 'sharp edges', high resolution power. In the present work the optimal conditions to obtain neutron radiography images by using the following film-converter screen systems, Kodak-AA/Gd vaporated; Kodak-AA/Gd metallic; Kodak-AA/LiF; Min-R/GdS{sub 2}O{sub 4}, have been determined. The irradiations were performed in a radiographic facility which was designed and constructed by the neutron radiography working group and is installed at the beamhole 08 of the IEA-R1 nuclear research reactor of the IPEN-CNEN/SP. In order to determine such conditions, the start point was to evaluate the neutron exposure interval for which the optical contrast is maximal and so quantify the sensitivity or capability to discern material thickness, as well as the spatial resolution achieved in the radiographic image, for these systems. The best results have been obtained for the Kodak-AA/Gd vaporated system which is able to discern, for example, 0,024 cm of lucite, with a maximal resolution of 22{mu}m. The radiography images presently obtained in IPEN-CNEN/SP have similar quality when compared to the ones from several other research centers, around the world, whose making use of the same film-converter screens systems. (author)

  16. Characterization of the Annular Core Research Reactor (ACRR) Neutron Radiography System Imaging Plane

    Science.gov (United States)

    Kaiser, Krista; Chantel Nowlen, K.; DePriest, K. Russell

    2016-02-01

    The Annular Core Research Reactor (ACRR) at Sandia National Laboratories (SNL) is an epithermal pool-type research reactor licensed up to a thermal power of 2.4 MW. The ACRR facility has a neutron radiography facility that is used for imaging a wide range of items including reactor fuel and neutron generators. The ACRR neutron radiography system has four apertures (65:1, 125:1, 250:1, and 500:1) available to experimenters. The neutron flux and spectrum as well as the gamma dose rate were characterized at the imaging plane for the ACRR's neutron radiography system for the 65:1, 125:1 and 250:1 apertures.

  17. Characterization of the Annular Core Research Reactor (ACRR Neutron Radiography System Imaging Plane

    Directory of Open Access Journals (Sweden)

    Kaiser Krista

    2016-01-01

    Full Text Available The Annular Core Research Reactor (ACRR at Sandia National Laboratories (SNL is an epithermal pool-type research reactor licensed up to a thermal power of 2.4 MW. The ACRR facility has a neutron radiography facility that is used for imaging a wide range of items including reactor fuel and neutron generators. The ACRR neutron radiography system has four apertures (65:1, 125:1, 250:1, and 500:1 available to experimenters. The neutron flux and spectrum as well as the gamma dose rate were characterized at the imaging plane for the ACRR's neutron radiography system for the 65:1, 125:1 and 250:1 apertures.

  18. The STING imaging system based on using neutrons and gammas

    Energy Technology Data Exchange (ETDEWEB)

    Barker, H.B. [SubAtomic Technologies, Inc., 4929 Hidden Meadow Way, Antelope, CA 95843 (United States); Maier, M.R. [SubAtomic Technologies, Inc., 4929 Hidden Meadow Way, Antelope, CA 95843 (United States)]. E-mail: mmaier@SubatomicInc.com

    2005-04-21

    We present a novel method for three-dimensional imaging of contrast agents in different specimens using neutrons. The contrast agent is an element with a high neutron capture cross section-e.g. B{sup 10}. This element emits a {gamma}-ray-478keV in the case of B{sup 10}-upon capturing a neutron. The {gamma}-rays are then imaged with suitable tomographic imaging methods. We present a method of using a shadow mask technique for imaging which needs only one exposure and can yield depth information in addition to the two-dimensional projection.

  19. The STING imaging system based on using neutrons and gammas

    Science.gov (United States)

    Barker, H. B.; Maier, M. R.

    2005-04-01

    We present a novel method for three-dimensional imaging of contrast agents in different specimens using neutrons. The contrast agent is an element with a high neutron capture cross section—e.g. B 10. This element emits a γ-ray—478 keV in the case of B 10—upon capturing a neutron. The γ-rays are then imaged with suitable tomographic imaging methods. We present a method of using a shadow mask technique for imaging which needs only one exposure and can yield depth information in addition to the two-dimensional projection.

  20. Fast Neutron Radiography at an RFQ Accelerator System

    Science.gov (United States)

    Daniels, G. C.; Franklyn, C. B.; Dangendorf, V.; Buffler, A.; Bromberger, B.

    This work introduces the Necsa Radio Frequency Quadrupole (RFQ) accelerator facility and its work concerning fast neutron radiography (FNR). Necsa operates a 4-5 MeV, up to 50 mA deuteron RFQ. The previous deuterium gas target station has been modified to enable producing a white neutron beam employing a solid B4C target. Furthermore, the high energy beam transport (HEBT) section is under adjustment to achieve a longer flight-path and a better focus. This work presents an overview of the facility, the modifications made, and introduces past and ongoing neutron radiography investigations.

  1. Near-barrier fusion of proton- and neutron-halo systems

    Science.gov (United States)

    Aguilera, E. F.

    2016-07-01

    It is shown that the behaviour of the fusion excitation functions for proton-halo and neutron-halo systems presents important differences, especially in the energy region slightly above the barrier. Measurements for 6He, 11Li and 11Be projectiles are discussed to exemplify the behaviour of neutron-halo systems, while experiments with 8B beams illustrate the situation for proton-halo nuclei. With respect to a standard benchmark, neutron- (proton-) halo systems show a fusion suppression (enhancement) above the barrier.

  2. Neutron Radiography

    Directory of Open Access Journals (Sweden)

    A. R. Reddy

    1982-07-01

    Full Text Available The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  3. Brazilian two-component TLD albedo neutron individual monitoring system

    International Nuclear Information System (INIS)

    Since 1983, Instituto de Radioprotecao e Dosimetria, Brazil, uses a TLD one-component albedo neutron monitor, which has a single different calibration factor specifically for each installation type. In order to improve its energy response, a two-component albedo monitor was developed, which measure the thermal neutron component besides the albedo one. The two-component monitor has been calibrated in reference neutron fields: thermal, five accelerator-produced monoenergetic beams (70, 144, 565, 1200 and 5000 keV) and five radionuclide sources (252Cf, 252Cf(D2O), 241Am-Be, 241Am-B and 238Pu-Be) at several distances. Since January 2008, mainly Brazilian workers who handle neutron sources at different distances and moderation, such as in well logging and calibration facilities are using it routinely.

  4. Neutron and photon transport calculations in fusion system. 2

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Satoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1998-03-01

    On the application of MCNP to the neutron and {gamma}-ray transport calculations for fusion reactor system, the wide range design calculation has been carried out in the engineering design activities for the international thermonuclear fusion experimental reactor (ITER) being developed jointly by Japan, USA, EU and Russia. As the objects of shielding calculation for fusion reactors, there are the assessment of dose equivalent rate for living body shielding and the assessment of the nuclear response for the soundness of in-core structures. In the case that the detailed analysis of complicated three-dimensional shapes is required, the assessment using MCNP has been carried out. Also when the nuclear response of peripheral equipment due to the gap streaming between blanket modules is evaluated with good accuracy, the calculation with MCNP has been carried out. The analyses of the shieldings for blanket modules and NBI port are explained, and the examples of the results of analyses are shown. In the blanket modules, there are penetrating holes and continuous gap. In the case of the NBI port, shielding plug cannot be installed. These facts necessitate the MCNP analysis with high accuracy. (K.I.)

  5. Neutron fluence rate measurements in a PGNAA 208-liter drum assay system using silicon carbide detectors

    Energy Technology Data Exchange (ETDEWEB)

    Dulloo, A.R. E-mail: dullooar@westinghouse.com; Ruddy, F.H.; Seidel, J.G.; Lee, S.; Petrovic, B.; McIlwain, M.E

    2004-01-01

    Pulsed prompt gamma neutron activation analysis (PGNAA) is being implemented for the nondestructive assay (NDA) of mercury, cadmium and lead in containers of radioactive waste. A PGNAA prototype system capable of assaying 208-liter (55-gallon) drums has already been built and demonstrated. As part of the evaluation of this system, the thermal neutron fluence rate distribution in a drum containing a combustible waste surrogate was measured during PGNAA runs using a silicon carbide neutron detector. The fast charge-collection time of this detector type enabled the investigation of the neutron kinetics at various locations within the matrix during and between pulses of the system's 14-MeV neutron source. As expected, the response of a SiC detector equipped with a lithium-6 fluoride layer is dominated by thermal neutron-induced events between pulses. The measurement results showed that the thermal neutron fluence rate is relatively uniform over a radial depth of several centimeters in the matrix region that contributes a significant fraction of the prompt gamma radiation incident on the system's photon detector.

  6. Neutron fluence rate measurements in a PGNAA 208-liter drum assay system using silicon carbide detectors

    Science.gov (United States)

    Dulloo, A. R.; Ruddy, F. H.; Seidel, J. G.; Lee, S.; Petrović, B.; McIlwain, M. E.

    2004-01-01

    Pulsed prompt gamma neutron activation analysis (PGNAA) is being implemented for the nondestructive assay (NDA) of mercury, cadmium and lead in containers of radioactive waste. A PGNAA prototype system capable of assaying 208-liter (55-gallon) drums has already been built and demonstrated. As part of the evaluation of this system, the thermal neutron fluence rate distribution in a drum containing a combustible waste surrogate was measured during PGNAA runs using a silicon carbide neutron detector. The fast charge-collection time of this detector type enabled the investigation of the neutron kinetics at various locations within the matrix during and between pulses of the system's 14-MeV neutron source. As expected, the response of a SiC detector equipped with a lithium-6 fluoride layer is dominated by thermal neutron-induced events between pulses. The measurement results showed that the thermal neutron fluence rate is relatively uniform over a radial depth of several centimeters in the matrix region that contributes a significant fraction of the prompt gamma radiation incident on the system's photon detector.

  7. Neutron fluence rate measurements in a PGNAA 208-liter drum assay system using silicon carbide detectors

    International Nuclear Information System (INIS)

    Pulsed prompt gamma neutron activation analysis (PGNAA) is being implemented for the nondestructive assay (NDA) of mercury, cadmium and lead in containers of radioactive waste. A PGNAA prototype system capable of assaying 208-liter (55-gallon) drums has already been built and demonstrated. As part of the evaluation of this system, the thermal neutron fluence rate distribution in a drum containing a combustible waste surrogate was measured during PGNAA runs using a silicon carbide neutron detector. The fast charge-collection time of this detector type enabled the investigation of the neutron kinetics at various locations within the matrix during and between pulses of the system's 14-MeV neutron source. As expected, the response of a SiC detector equipped with a lithium-6 fluoride layer is dominated by thermal neutron-induced events between pulses. The measurement results showed that the thermal neutron fluence rate is relatively uniform over a radial depth of several centimeters in the matrix region that contributes a significant fraction of the prompt gamma radiation incident on the system's photon detector

  8. Development of a modular directional and spectral neutron detection system using solid-state detectors

    International Nuclear Information System (INIS)

    A detection system using room-temperature, microstructured solid-state thermal neutron detectors with very low leakage current has been developed at Rensselaer Polytechnic Institute (RPI) with the ability to provide positional and spectral information about an unknown neutron source. The Directional and Spectral Neutron Detection System (DSNDS) utilizes a set of small-but-scalable, zero-bias solid-state thermal neutron detectors which have demonstrated high thermal neutron efficiency and adequate gamma insensitivity. The DSNDS can gather spectral information about an unknown neutron source with a relatively small number of detectors, simplifying the detector electronics and minimizing cost; however, the DSNDS is modular in design, providing the capability to increase the detection efficiency and angular resolution. The system used in this paper was comprised of a stack of five high-density polyethylene (HDPE) disks with a thickness of 5 cm and a diameter of 30 cm, the middle disk containing 16 detectors positioned as one internal (moderated) and one external (unmoderated) ring of solid-state neutron detectors. These two detector rings provide the ability to determine the directionality of a neutron source. The system gathers spectral information about a neutron source in two ways: by measuring the relative responses of the internal ring of detectors as well as measuring the ratio of the internal-to-external detector responses. Experiments were performed with variable neutron spectra: a 252Cf spontaneous fission neutron source which was HDPE moderated, HDPE reflected, lead (Pb) shielded, and bare in order to benchmark the system for spectral sensitivity. Simulations were performed in order to characterize the neutron spectra corresponding to each of the source configurations and showed agreement with experimental measurements. The DSNDS demonstrates the ability to determine the relative angle of the source and the hardness of the neutron spectrum. By using the

  9. Neutron cross-sections for advanced nuclear systems: the n_TOF project at CERN

    Science.gov (United States)

    Barbagallo, M.; Mastromarco, M.; Colonna, N.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Duran, I.; Dressler, R.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondalaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.; Žugec, P.

    2014-12-01

    The study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n_TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.

  10. Neutron cross-sections for advanced nuclear systems: the n_TOF project at CERN

    Directory of Open Access Journals (Sweden)

    Barbagallo M.

    2014-01-01

    Full Text Available The study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n_TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.

  11. Automatic neutron PSD transmission from a process computer to a timeshare system

    International Nuclear Information System (INIS)

    A method for automatically telephoning, connecting, and transmitting neutron power-spectral density data from a CDC-1700 process control computer to a PDP-10 time-share system is described. Detailed program listings and block diagrams are included

  12. Design Verification Report Neutron Radiography Facility (NRF) TRIGA Fuel Storage Systems

    International Nuclear Information System (INIS)

    This report outlines the methods, procedures, and outputs developed during the Neutron Radiography Facility (NRF) Training, Research and Isotope Production, General Atomics (TRIGA) fuel storage system design and fabrication

  13. Multi-Frame Energy-Selective Imaging System for Fast-Neutron Radiography

    OpenAIRE

    Dangendorf, Volker; Bar, Doron; Bromberger, Benjamin; Feldman, Gennady; Goldberg, Mark B.; Lauck, Ronald; Mor, Ilan; Tittelmeier, Kai; Vartsky, David; Weierganz, Mathias

    2009-01-01

    A new instrument for high resolution imaging of fast-neutrons is presented here. It is designed for energy selective radiography in nanosecond-pulsed broad-energy (1 - 10 MeV) neutron beams. The device presented here is based on hydrogenous scintillator screens and single- or multiple-gated intensified camera systems (ICCD). A key element is a newly developed optical amplifier which generates sufficient light for the high-speed intensified camera system, even from such faint light sources as ...

  14. Determination of Dead Time of Neutron Counting System for Use of Reactor Start up

    Institute of Scientific and Technical Information of China (English)

    ZHAOYu-sen; ZHAOPeng-yu

    2003-01-01

    The dead time is important parameter of neutron counting system for use of reactor start up. It is relative to accurate determination of critical mass and the safety during reactor start up. So, it is important that dear time is measured accurately. There are many methods for measuring the dead time, but they are rare to be suitable for neutron counting system, which has wide variant range.

  15. On-line control and detection system for crystalline neutron for spectrometer

    International Nuclear Information System (INIS)

    On-line control and detection system for the crystalline neutron three-axial spectrometer is described, the system being based on microcomputer ''Ehlektronika-60'' and electron units in KAMAK standard. System software is proefly described. The application of this system permits to speed up measurements 2-3 times in comparison with control systems of HELENA type

  16. Statistical estimation of the performance of a fast-neutron multiplicity system for nuclear material accountancy

    Energy Technology Data Exchange (ETDEWEB)

    Chichester, David L., E-mail: david.chichester@inl.gov [Idaho National Laboratory, 2525 N. Fremont Avenue, Idaho Falls, ID 83415 (United States); Thompson, Scott J.; Kinlaw, Mathew T.; Johnson, James T. [Idaho National Laboratory, 2525 N. Fremont Avenue, Idaho Falls, ID 83415 (United States); Dolan, Jennifer L.; Flaska, Marek; Pozzi, Sara A. [Department of Nuclear Engineering & Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109-2104 (United States)

    2015-06-01

    Statistical analyses have been performed to develop bounding estimates of the expected performance of a conceptual fast-neutron multiplicity system (FNMS) for assaying plutonium. The conceptual FNMS design includes 32 cubic liquid scintillator detectors, measuring 7.62 cm per side, configured into 4 stacked rings of 8 detectors each. Expected response characteristics for the individual FNMS detectors, as well as the response characteristics of the entire FNMS, were determined using Monte Carlo simulations based on prior validation experiments. The results from these simulations were then used to estimate the Pu assay capabilities of the FNMS in terms of counting time, assay mass, and assay mass variance, using assay mass variance as a figure of merit. The analysis results are compared against a commonly used thermal-neutron coincidence counter. The advantages of using a fast-neutron counting system versus a thermal-neutron counting system are significant. Most notably, the time required to perform an assay to an equivalent assay mass variance is greatly reduced with a fast-neutron system, by more than an order of magnitude compared with that of the thermal-neutron system, due to the reduced probability of random summing with the fast system. The improved FNMS performance is especially relevant for assays involving Pu masses of 10 g or more.

  17. Triton burnup measurements in KSTAR using a neutron activation system

    Science.gov (United States)

    Jo, Jungmin; Cheon, MunSeong; Kim, Jun Young; Rhee, T.; Kim, Junghee; Shi, Yue-Jiang; Isobe, M.; Ogawa, K.; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-11-01

    Measurements of the time-integrated triton burnup for deuterium plasma in Korea Superconducting Tokamak Advanced Research (KSTAR) have been performed following the simultaneous detection of the d-d and d-t neutrons. The d-d neutrons were measured using a 3He proportional counter, fission chamber, and activated indium sample, whereas the d-t neutrons were detected using activated silicon and copper samples. The triton burnup ratio from KSTAR discharges is found to be in the range 0.01%-0.50% depending on the plasma conditions. The measured burnup ratio is compared with the prompt loss fraction of tritons calculated with the Lorentz orbit code and the classical slowing-down time. The burnup ratio is found to increase as plasma current and classical slowing-down time increase.

  18. The EURITRACK project: development of a tagged neutron inspection system for cargo containers

    Science.gov (United States)

    Perot, Bertrand; Perret, Gregory; Mariani, Alain; Ma, Jean-Luc; Szabo, Jean-Louis; Mercier, Emmanuel; Sannie, Guillaume; Viesti, Giuseppe; Nebbia, Giancarlo; Pesente, Silvia; Lunardon, Marcello; Formisano, Paola; Moretto, Sandra; Fabris, Daniela; Zenoni, Aldo; Bonomi, Germano; Donzella, Antonietta; Fontana, Andrea; Boghen, Gaia; Valkovic, Vladivoj; Sudac, Darovin; Moszynski, Marek; Batsch, Tadeusz; Gierlik, Michal; Wolski, Dariusz; Klamra, Wlodzimierz; Isaksson, Patrick; Le Tourneur, Philippe; Lhuissier, Miguel; Colonna, Annamaria; Tintori, Carlo; Peerani, Paolo; Sequeira, Vitor; Salvato, Martino

    2006-05-01

    The EURopean Illicit TRAfficing Countermeasures Kit project is part of the 6th European Union Framework Program, and aims at developing a neutron inspection system for detecting threat materials (explosives, drugs, etc.) in cargo containers. Neutron interaction in the container produces specific gamma-rays used to determine the chemical composition of the inspected material. An associated particle sealed tube neutron generator is developed to allow precise location of the interaction point by direction and time-of-flight measurements of the neutrons tagged by alpha-particles. The EURITRACK project consists in developing: a transportable deuterium-tritium neutron generator including a position sensitive alpha detector (8×8 matrix of YAP:Ce crystals coupled to a multi-anode photomultiplier), fast neutron and gamma-ray detectors, front-end electronics to perform coincidence and spectroscopic measurements, and an integrated software which manages neutron generator and detectors positioning, data acquisition and analysis. Hardware components have been developed and tested by the consortium partners. Current status of this work and provisional performances of the system assessed by Monte Carlo calculations are presented.

  19. Power spectral analysis for a subcritical reactor system driven by a pulsed spallation neutron source

    International Nuclear Information System (INIS)

    A series of power spectral analyses for a thermal subcritical reactor system driven by a pulsed spallation neutron source was carried out at Kyoto University Critical Assembly (KUCA), to determine the prompt-neutron decay constant of the Accelerator-Driven System (ADS). High-energy protons (100 MeV) obtained from the fixed field alternating gradient accelerator were injected onto a lead-bismuth target, whereby the spallation neutrons were generated. In the cross-power spectral density between time-sequence signal data of two neutron detectors, many delta-function-like peaks at the integral multiple of pulse repetition frequency could be observed. However, no continuous reactor-noise component could be measured. This is because these detectors have too high count-rate to be placed closely to the core. From the point data of these delta-function-like peaks, the prompt-neutron decay constant could be determined. At a slightly subcritical state, the decay constant was consistent with that obtained by a previous power spectral analysis for a pulsed 14 MeV neutron source and by a pulsed neutron experiment. At another deeply subcritical state, however, the present analysis leads to an underestimate of the decay constant. (author)

  20. Dynamic neutron scattering on incoherent systems using efficient resonance spin flip techniques

    Energy Technology Data Exchange (ETDEWEB)

    Häussler, Wolfgang [Heinz Maier-Leibnitz Zentrum, Technische Universität München, D-85748 Garching, Germany and Physik-Department E21, Technische Universität München, D-85748 Garching (Germany); Kredler, Lukas [Physik-Department E21, Technische Universität München, D-85748 Garching (Germany)

    2014-05-15

    We have performed numerical ray-tracing Monte-Carlo-simulations of incoherent dynamic neutron scattering experiments. We intend to optimize the efficiency of incoherent measurements depending on the fraction of neutrons scattered without and with spin flip at the sample. In addition to conventional spin echo, we have numerically and experimentally studied oscillating intensity techniques. The results point out the advantages of these different spin echo variants and are an important prerequisite for neutron resonance spin echo instruments like RESEDA (FRM II, Munich), to choose the most efficient technique depending on the scattering vector range and the properties of the sample system under study.

  1. The use of neutron generators for the detection of illicit materials in the sea transportation system

    International Nuclear Information System (INIS)

    In today's society acts of terrorism must involve in some stages the illicit trafficking either of explosives, chemical agents and/or nuclear materials. Therefore society must rely on an anti-trafficking infrastructure which encompasses responsible authorities, field personnel and adequate instrumental networks. Modern inspection systems for personnel, parcel, vehicle and cargo, as noninvasive imaging techniques, are based on the use of nuclear analytical methods. The inspection systems make use of penetrating radiation (neutrons, gamma and x-rays) in a scanning geometry, with the detection of radiation either transmitted or produced in the interrogated object. Explosives and chemical agent detection systems are based on the fact that the problem of identification can be reduced to the measurement of elemental concentrations. Different nuclear analytical techniques could be used for this purpose; however the use of neutrons has some specific advantages due to the high penetrability in large payloads. Of special interest is the design and use of a transportable neutron system coupled to a gamma-ray radiographic device for inspecting large containers searching for contraband, explosives, weapons etc. The use of neutron induced reactions for non-destructive bulk elemental analysis is well documented. All neutrons, in particular fast neutrons, are well suited to explore large volume samples because of their high penetration in bulk material. Fast neutrons can be produced efficiently and economically by natural radioactive sources, small accelerators or compact electronic neutron generators, making possible the use of neutron based techniques in field applications. Gamma-rays produced by irradiating the sample with neutrons gives the elemental composition of the material, moreover, knowing the nuclear cross-sections and estimating the absorption factors in the different materials, it is possible to perform a quantitative analysis of elements in the sample even in depth

  2. Fundamental design of systems and facilities for cold neutron source in the Hanaro

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bong Soo; Jeong, H. S.; Kim, Y. K.; Wu, S. I

    2006-01-15

    The CNS(Cold Neutron Source) development project has been carried out as the partial project of the reactor utilization R and D government enterprise since 2003. In the advantage of lower energy and long wave length for the cold neutron, it can be used with the essential tool in order to investigate the structure of protein, amino-acid, DNA, super lightweight composite and advanced materials in the filed of high technology. This report is mainly focused on the basic design of the systems and facilities for the HANARO cold neutron source, performed during the second fiscal project year.

  3. Measurement and simulation of stilbene scintillator response for the KSTAR neutron diagnostic system

    Science.gov (United States)

    Lee, Seung Kyu; Son, Jae Bum; Kang, JeongSoo; Seo, Hee; Won, Byung-Hee; Park, Se-Hwan; Kim, Ho-Dong; Kang, Byoung Hwi; Kim, Gi Dong; Kim, Yong Kyun

    2014-03-01

    The Korea Superconducting Tokamak Advanced Research (KSTAR) project was started in December 1995, and its construction was completed in August 2007. On June 13, 2008, the KSTAR successfully produced its first plasma, and the diagnostic systems played an important role in achieving the first successful plasma operation. In fact, various diagnostic systems are required to protect reactor devices, to the control plasma, and to evaluate the plasma's performance in fusion reactors. One of the most essential tools for control of the burning plasma in fusion reactors may be a neutron diagnostic system to prove the presence of the plasma by measuring the neutrons from fusion reactions directly. The stilbene scintillator has been proposed as a good candidate for a neutron diagnostic system in the KSTAR fusion reactor because the stilbene scintillator is well-known to be an excellent material for detection of fast neutrons in a high gamma-ray background environment. If fast-neutron spectra are to be measured amid a high gamma-ray background, especially-designed electronics are necessary. For instance, a digital charge pulse shape discrimination (PSD) method, utilizing a total-to-partial-charge-ratio analysis, discriminates neutron from gamma-ray signals. Also, a flash analog-to-digital convertor (FADC) with a field-programmable gate array (FPGA) increases the data-transfer rate for real-time evaluation of plasma performance. In the present study, measurements and simulations were performed in order to confirm the stilbene scintillator's response to D-D fusion reaction neutrons. Additionally, the count-rate limit of the neutron diagnostic system was determined by using measurements with a 252Cf source at different distances.

  4. Calculations to support JET neutron yield calibration: Modelling of the JET remote handling system

    Energy Technology Data Exchange (ETDEWEB)

    Snoj, Luka, E-mail: luka.snoj@ijs.si [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); EURATOM-MHEST Association, Reactor Physics Division, Jožef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Lengar, Igor; Čufar, Aljaž [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); EURATOM-MHEST Association, Reactor Physics Division, Jožef Stefan Institute, Jamova Cesta 39, SI-1000 Ljubljana (Slovenia); Syme, Brian; Popovichev, Sergey [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB, OXON (United Kingdom); Conroy, Sean [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); EURATOM-VR Association, Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Meredith, Lewis [JET-EFDA, Culham Science Centre, OX14 3DB Abingdon (United Kingdom); EURATOM-CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB, OXON (United Kingdom)

    2013-08-15

    Highlights: ► We model JET remote handling system in MCNP. ► We examine the effect of JET remote handling system on neutron monitor response. ► The integral effect of JET RH system on neutron monitors is less than 5%. -- Abstract: After the coated CFC wall to ITER-Like Wall (Beryllium/Tungsten/Carbon) transition in 2010–2011, confirmation of the neutron yield calibration will be ensured by direct measurements using a calibrated {sup 252}Cf neutron source deployed by the in-vessel remote handling boom and Mascot manipulator inside the JET vacuum vessel. Neutronic calculations are required to calculate the effects of the JET remote handling (RH) system on the neutron monitors. We developed a simplified geometrical computational model of the JET remote handling system in MCNP. In parallel we developed a script that translates the RH movement data to transformations of individual geometrical parts of the RH model in MCNP. After that a benchmarking of the model was performed to verify and validate the accordance of the target positions of source and RH system with the ones from our model. In the last phase we placed the JET RH system in the simplified MCNP model of the JET tokamak and studied its effect on neutron monitor response for some example source positions and boom configurations. As the correction factors due to presence of the JET RH system can potentially be significant in cases when the boom is blocking a port close to the detector under investigation, we have chosen boom configurations so that this is avoided in the vast majority of the source locations. Examples are given.

  5. Single-crystal neutron diffraction studies of hydrogen-bonded systems: Two recent examples from IPNS

    Energy Technology Data Exchange (ETDEWEB)

    Koetzle, Thomas F. [IPNS Division, Argonne National Laboratory, Argonne, IL 60439 (United States)], E-mail: tkoetzle@anl.gov; Piccoli, Paula M.B.; Schultz, Arthur J. [IPNS Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2009-02-21

    Beginning with work in the 1950s at the first generation of research reactors, studies of hydrogen-bonded systems have been a prime application for single-crystal neutron diffraction. The range of systems studied was extended in the 1960s and 1970s, with the advent of high flux reactor sources, and beginning around 1980 studies at pulsed neutron sources have made increasingly important contributions. Recently at the Argonne Intense Pulsed Neutron Source (IPNS), working with collaborators, we completed two studies of hydrogen-bonded systems that will serve to illustrate topics of current interest. In the first study, on andrographolide, an active diterpenoid natural product, our neutron diffraction results definitively characterize the hydrogen-bonding interactions. The second IPNS study is on tetraacetylethane (TAE), a {beta}-diketone enol system with a very short, strong intramolecular O-H...O hydrogen bond. At IPNS, we have determined the neutron crystal structure of TAE at five temperatures between 20 and 298 K to investigate changes in the structure with temperature and to probe for disorder. Despite the successes illustrated by the two examples presented here and by many other studies, at present applications of single-crystal neutron diffraction continue to be extremely flux limited and constrained by the requirement for mm-size crystals for many problems. These limitations are being addressed through the realization of powerful instruments at a new generation of pulsed neutron sources, including in the USA the TOPAZ and MaNDi single-crystal diffractometers that are under development at the Spallation Neutron Source (SNS)

  6. Single-crystal neutron diffraction studies of hydrogen-bonded systems: Two recent examples from IPNS

    International Nuclear Information System (INIS)

    Beginning with work in the 1950s at the first generation of research reactors, studies of hydrogen-bonded systems have been a prime application for single-crystal neutron diffraction. The range of systems studied was extended in the 1960s and 1970s, with the advent of high flux reactor sources, and beginning around 1980 studies at pulsed neutron sources have made increasingly important contributions. Recently at the Argonne Intense Pulsed Neutron Source (IPNS), working with collaborators, we completed two studies of hydrogen-bonded systems that will serve to illustrate topics of current interest. In the first study, on andrographolide, an active diterpenoid natural product, our neutron diffraction results definitively characterize the hydrogen-bonding interactions. The second IPNS study is on tetraacetylethane (TAE), a β-diketone enol system with a very short, strong intramolecular O-H...O hydrogen bond. At IPNS, we have determined the neutron crystal structure of TAE at five temperatures between 20 and 298 K to investigate changes in the structure with temperature and to probe for disorder. Despite the successes illustrated by the two examples presented here and by many other studies, at present applications of single-crystal neutron diffraction continue to be extremely flux limited and constrained by the requirement for mm-size crystals for many problems. These limitations are being addressed through the realization of powerful instruments at a new generation of pulsed neutron sources, including in the USA the TOPAZ and MaNDi single-crystal diffractometers that are under development at the Spallation Neutron Source (SNS).

  7. Single-crystal neutron diffraction studies of hydrogen-bonded systems: Two recent examples from IPNS

    Science.gov (United States)

    Koetzle, Thomas F.; Piccoli, Paula M. B.; Schultz, Arthur J.

    2009-02-01

    Beginning with work in the 1950s at the first generation of research reactors, studies of hydrogen-bonded systems have been a prime application for single-crystal neutron diffraction. The range of systems studied was extended in the 1960s and 1970s, with the advent of high flux reactor sources, and beginning around 1980 studies at pulsed neutron sources have made increasingly important contributions. Recently at the Argonne Intense Pulsed Neutron Source (IPNS), working with collaborators, we completed two studies of hydrogen-bonded systems that will serve to illustrate topics of current interest. In the first study, on andrographolide, an active diterpenoid natural product, our neutron diffraction results definitively characterize the hydrogen-bonding interactions. The second IPNS study is on tetraacetylethane (TAE), a β-diketone enol system with a very short, strong intramolecular O-H⋯O hydrogen bond. At IPNS, we have determined the neutron crystal structure of TAE at five temperatures between 20 and 298 K to investigate changes in the structure with temperature and to probe for disorder. Despite the successes illustrated by the two examples presented here and by many other studies, at present applications of single-crystal neutron diffraction continue to be extremely flux limited and constrained by the requirement for mm-size crystals for many problems. These limitations are being addressed through the realization of powerful instruments at a new generation of pulsed neutron sources, including in the USA the TOPAZ and MaNDi single-crystal diffractometers that are under development at the Spallation Neutron Source (SNS).

  8. Spectroscopic neutron radiography for a cargo scanning system

    Science.gov (United States)

    Rahon, Jill; Danagoulian, Areg; MacDonald, Thomas D.; Hartwig, Zachary S.; Lanza, Richard C.

    2016-06-01

    Detection of cross-border smuggling of illicit materials and contraband is a challenge that requires rapid, low-dose, and efficient radiographic technology. The work we describe here is derived from a technique which uses monoenergetic gamma rays from low energy nuclear reactions, such as 11B(d,nγ)12C, to perform radiographic analysis of shipping containers. Transmission ratios of multiple monoenergetic gamma lines resulting from several gamma producing nuclear reactions can be employed to detect materials of high atomic number (Z), the details of which will be described in a separate paper. Inherent in this particular nuclear reaction is the production of fast neutrons which could enable neutron radiography and further characterization of the effective-Z of the cargo, especially within the range of lower Z. Previous research efforts focused on the use of total neutron counts in combination with X-ray radiography to characterize the hydrogenous content of the cargo. We present a technique of performing transmitted neutron spectral analysis to reconstruct the effective Z and potentially the density of the cargo. This is made possible by the large differences in the energy dependence of neutron scattering cross-sections between hydrogenous materials and those of higher Z. These dependencies result in harder transmission spectra for hydrogenous cargoes than those of non-hydrogenous cargoes. Such observed differences can then be used to classify the cargo based on its hydrogenous content. The studies presented in this paper demonstrate that such techniques are feasible and can provide a contribution to cargo security, especially when used in concert with gamma radiography.

  9. Results of two Albedo systems in a Brazilian neutron individual monitoring comparison

    International Nuclear Information System (INIS)

    In 2012, the Brazilian National Metrology Laboratory sponsored the First Brazilian National Comparison of Measurements with Neutron Individual Monitors. The Thermoluminescent Dosimetry Laboratory of the Institute of Radioprotection and Dosimetry IRD/CNEN-RJ participated in it with its two albedo systems: one-component and two-component albedo monitors. The one component is composed by two capsules in a belt and each capsule has a pair of TLD for albedo neutron detection. The two-component consists of one capsule in a belt with two pairs of TLD: one pair for the measurement of the incident neutrons and the other for albedo neutrons. This paper presents the results of both systems in that comparison. The irradiation of the monitors was performed in four different values of Hp(10,0 deg) in a traceable 241Am-Be ISO standard reference neutron field. For both systems, it was observed that the evaluated dose values are very close to the reference dose values which each monitor has been undergone. Considering the mean values, the two-component albedo monitor has performance a little bit better than the one-component one but the results of both systems are statistically equal. For both systems, the responses are close to 1 and inside the trumpet curves. Thus, the results of two systems confirm their good accuracy and reproducibility in the tested neutron field and indicate that are able to evaluate the occupational neutron doses. This work confirms the importance of the inter-laboratory comparison programs to verification of the reliability of individual monitoring systems. (author)

  10. Results of two Albedo systems in a Brazilian neutron individual monitoring comparison

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Everton R.; Martins, Marcelo M.; Mauricio, Claudia L.P.; Freitas, Bruno M., E-mail: everton@ird.gov.br, E-mail: marcelo@ird.gov.br, E-mail: claudia@ird.gov.br, E-mail: brunofreitas@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Dosimetria

    2013-07-01

    In 2012, the Brazilian National Metrology Laboratory sponsored the First Brazilian National Comparison of Measurements with Neutron Individual Monitors. The Thermoluminescent Dosimetry Laboratory of the Institute of Radioprotection and Dosimetry IRD/CNEN-RJ participated in it with its two albedo systems: one-component and two-component albedo monitors. The one component is composed by two capsules in a belt and each capsule has a pair of TLD for albedo neutron detection. The two-component consists of one capsule in a belt with two pairs of TLD: one pair for the measurement of the incident neutrons and the other for albedo neutrons. This paper presents the results of both systems in that comparison. The irradiation of the monitors was performed in four different values of H{sub p}(10,0 deg) in a traceable {sup 241}Am-Be ISO standard reference neutron field. For both systems, it was observed that the evaluated dose values are very close to the reference dose values which each monitor has been undergone. Considering the mean values, the two-component albedo monitor has performance a little bit better than the one-component one but the results of both systems are statistically equal. For both systems, the responses are close to 1 and inside the trumpet curves. Thus, the results of two systems confirm their good accuracy and reproducibility in the tested neutron field and indicate that are able to evaluate the occupational neutron doses. This work confirms the importance of the inter-laboratory comparison programs to verification of the reliability of individual monitoring systems. (author)

  11. Dual-particle imaging system based on simultaneous detection of photon and neutron collision events

    International Nuclear Information System (INIS)

    A dual-particle imaging (DPI) system capable of simultaneously detecting and imaging fast neutrons and photons has been designed and built. Imaging fast neutrons and photons simultaneously is particularly desirable for nuclear nonproliferation and/or safeguards applications because typical sources of interest (special nuclear material) emit both particle types. The DPI system consists of three detection planes: the first two planes consist of organic-liquid scintillators and the third plane consists of NaI(Tl) inorganic scintillators. Pulse shape discrimination technique(s) may be used for the liquid scintillators to differentiate neutron and photon pulses whereas the NaI(Tl) scintillators are highly insensitive to neutrons. A prototype DPI system was set up using a digital data acquisition system as a proof of concept. Initial measurements showed potential for use of the DPI system with special nuclear material. The DPI system has efficiencies of the order of 10−4 correlated counts per incident particles for both neutron and photon correlated counts, with simple-backprojection images displaying peaks within a few degrees of the source location. This uncertainty is expected to decrease with more extensive data interpretation

  12. Feasibility study of a hybrid subcritical fission system driven by Plasma-Focus fusion neutrons

    International Nuclear Information System (INIS)

    Highlights: • A model of a subcritical cascade driven by a Plasma Focus device is presented. • Optimum parameters to achieve given levels of neutron amplification are produced. • Monte Carlo calculations for spherical shells of enriched Uranium were performed. • Break-even conditions can be achieved with Plasma Focus of tens of kJ. - Abstract: A feasibility analysis of a hybrid fusion–fission system consisting of a two-stage spherical subcritical cascade driven by a Plasma Focus device is presented. The analysis is based on the one-group neutron diffusion equation, which was appropriately cast to assess the neutronic amplification of a spherical configuration. A design chart was produced to estimate the optimum dimensions of the fissile shells required to achieve different levels of neutron amplification. It is found that cascades driven by Plasma Focus of tens of kJ are feasible. The results were corroborated by means of Monte Carlo calculations

  13. Effect of shell structure on neutron multiplicity of fissioning systems 220,222,224Th nuclei

    Directory of Open Access Journals (Sweden)

    Goyal Savi

    2015-01-01

    Full Text Available The pre- and post-scission neutron multiplicities have been extracted for the 220,222,224Th nuclei for the excitation energy range of 40 MeV to 64 MeV using the National Array of Neutron Detectors (NAND. The Th isotopes are populated from the fusion reaction of 16O+204,206,208Pb systems in order to investigate the dynamics of fusion-fission reactions using the neutron multiplicity as a probe. The theoretical calculations were performed using the Bohr-Wheeler fission width as well as the dissipative dynamical fission width from Kramers prescription. It is observed that the Bohr-Wheeler fission width underestimates the pre-scission yields to a large extent. A large amount of dissipation is required in the Kramers width to fit the observed pre-scission neutron multiplicities.

  14. Generation of high-energy neutrons with the 300-ps-laser system PALS

    Institute of Scientific and Technical Information of China (English)

    J.Krsa; D.Klír; A.Velyhan; E.Krousky; M.Pfeifer; K.Rez; J.Cikhardt; K.Turek; J.Ullschmied; K.Jungwirth

    2014-01-01

    The laser system PALS,as a driver of a broad-beam ion source,delivered deuterons which generated neutrons with energies higher than 14 Me V through the 7Li(d,n)8 Be reaction.Deuterons with sub-Me V energy were accelerated from the front surface of a massive CD2 target in the backward direction with respect to the laser beam vector.Simultaneously,neutrons were emitted from the primary CD2 target and a secondary Li F catcher.The total maximum measured neutron yield from 2D(d,n)3He,7Li(d,n)8Be,12C(d,n)13N reactions was ~3.5(±0.5) × 108 neutrons/shot.

  15. Automatic pneumatic source-control system for positioning gamma and neutron calibration sources

    International Nuclear Information System (INIS)

    A microcomputer-based source-control system was developed to move gamma and neutron calibration sources into position for sample irradiation. In addition to monitoring interlocks and system status, the computer calculates for gamma sources the time required for a requested exposure at a specified distance. All system use data is stored, and monthly reports are generated

  16. System of adjoint P1 equations for neutron moderation; Sistema de equacoes P1 adjuntas para a moderacao de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Aquilino Senra; Silva, Fernando Carvalho da; Cardoso, Carlos Eduardo Santos [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear

    2000-07-01

    In some applications of perturbation theory, it is necessary know the adjoint neutron flux, which is obtained by the solution of adjoint neutron diffusion equation. However, the multigroup constants used for this are weighted in only the direct neutron flux, from the solution of direct P1 equations. In this work, this procedure is questioned and the adjoint P1 equations are derived by the neutron transport equation, the reversion operators rules and analogies between direct and adjoint parameters. (author)

  17. Scintillation spectrometer system for measuring fast-neutron spectra in beam geometry

    Energy Technology Data Exchange (ETDEWEB)

    Simons, G G; Larson, J M; Reynolds, R S

    1977-05-01

    A high-energy liquid-organic scintillation spectrometer system is described. This spectrometer was developed to measure neutron spectra in extracted beams from zero-power fast reactors. The highly efficient NE-213 scintillation solution was used as the neutron detection medium. Identification and removal of gamma-ray-induced events was accomplished using electronic pulse shape discrimination. Instrumentation used to process the discrete pulses stemming from neutron and gamma-ray interactions, within the scintillation solution, is described in detail. Evaluation of the system's performance is discussed for a gamma-ray discrimination ratio of nominally 1000:1, a total countrate of 3000 cps, and a dynamic range corresponding to neutron energies from 1 to 10 MeV. Operation above 10 MeV is certainly possible. However, since the neutron flux above 10 MeV was negligible in the radiation fields of interest in this work, the operating characteristics of the spectrometer were not evaluated above 10 MeV. Neutron spectra are reported for extracted beam measurements made on ZPPR assembly 4, phase 2.

  18. Conceptual study of advanced PWR core design. Development of advanced PWR core neutronics analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyo; Kim, Seung Cho; Kim, Taek Kyum; Cho, Jin Young; Lee, Hyun Cheol; Lee, Jung Hun; Jung, Gu Young [Seoul National University, Seoul (Korea, Republic of)

    1995-08-01

    The neutronics design system of the advanced PWR consists of (i) hexagonal cell and fuel assembly code for generation of homogenized few-group cross sections and (ii) global core neutronics analysis code for computations of steady-state pin-wise or assembly-wise core power distribution, core reactivity with fuel burnup, control rod worth and reactivity coefficients, transient core power, etc.. The major research target of the first year is to establish the numerical method and solution of multi-group diffusion equations for neutronics code development. Specifically, the following studies are planned; (i) Formulation of various numerical methods such as finite element method(FEM), analytical nodal method(ANM), analytic function expansion nodal(AFEN) method, polynomial expansion nodal(PEN) method that can be applicable for the hexagonal core geometry. (ii) Comparative evaluation of the numerical effectiveness of these methods based on numerical solutions to various hexagonal core neutronics benchmark problems. Results are follows: (i) Formulation of numerical solutions to multi-group diffusion equations based on numerical methods. (ii) Numerical computations by above methods for the hexagonal neutronics benchmark problems such as -VVER-1000 Problem Without Reflector -VVER-440 Problem I With Reflector -Modified IAEA PWR Problem Without Reflector -Modified IAEA PWR Problem With Reflector -ANL Large Heavy Water Reactor Problem -Small HTGR Problem -VVER-440 Problem II With Reactor (iii) Comparative evaluation on the numerical effectiveness of various numerical methods. (iv) Development of HEXFEM code, a multi-dimensional hexagonal core neutronics analysis code based on FEM. In the target year of this research, the spatial neutronics analysis code for hexagonal core geometry(called NEMSNAP-H temporarily) will be completed. Combination of NEMSNAP-H with hexagonal cell and assembly code will then equip us with hexagonal core neutronics design system. (Abstract Truncated)

  19. Development and characterization of two-component albedo based neutron individual monitoring system using thermoluminescent detectors

    International Nuclear Information System (INIS)

    A TLD-albedo based two-component neutron individual monitoring system was developed and characterized in this work. The monitor consists of a black plastic holder, an incident neutron boron loaded shield, a moderator polyethylene body (to increase its response), two pairs of TLD-600 and TLD-700 (one pair to each component) and an adjustable belt. This monitoring system was calibrated in thermal neutron fields and in 70 keV, 144 keV, 565 keV, 1.2 MeV and 5 MeV monoenergetic neutron fields. In addition, it was calibrated in 252Cf(D2O), 252Cf, 241Am-B, 241Am-Be and 238Pu-Be source fields. For the latter, the lower detection levels are, respectively, 0.009 mSv, 0.06 mSv, 0.12 mSv, 0.09 mSv and 0.08 mSv. The participation in an international intercomparison sponsored by IAEA with simulated workplace fields validated the system. The monitoring system was successfully characterized in the ISO 21909 standard and in an IRD - the Brazilian Institute for Radioprotection and Dosimetry - technical regulation draft. Nowadays, the neutron individual system is in use by IRD for whole body individual monitoring of five institutions, which comprehend several activities. (author)

  20. Dynamic linear calibration method for a wide range neutron flux monitor system in ITER

    International Nuclear Information System (INIS)

    As a key part of the diagnosis system in the International Thermonuclear Experimental Reactor (ITER), the neutron flux monitor (NFM), which measures the neutron intensity of the fusion reaction, is a Counting-Campbelling system with a large dynamic counting range. A dynamic linear calibration method is proposed in this paper to solve the problem of cross-over between the different counting and Campbelling channels, and improve the accuracy of the cross-calibration for long-term operation. The experimental results show that the NFM system with the dynamic linear calibration system can obtain the neutron flux of the fusion reactor in real time and realize the seamless measurement area connection between the two channels. (authors)

  1. Grazing incidence polarized neutron scattering in reflection geometry from nanolayered spintronic systems

    Indian Academy of Sciences (India)

    Amitesh Paul

    2012-01-01

    This review summarizes recent experimental investigations using neutron scattering on layered nanomagnetic systems (accentuating my contribution), which have applications in spintronics also. Polarized neutron investigations of such artificially structured materials are basically done to understand the interplay between structure and magnetism confined within the nanometer scale that can be additionally depth-resolved. Details of the identification of buried domains and their nature of lateral and vertical correlations within the systems are important. A particularly interesting aspect that has emerged over the years is the capability to measure polarized neutron scattering in directions parallel and perpendicular to the applied field direction (which is also the quantization axis for neutron polarizations). This was added with the capability of measuring in specular as well as in off-specular geometry. Distorted wave Born approximation (DWBA) theory for neutrons has proved to be a remarkable development in the quantitative analysis of the scattering data measured simultaneously for specular and off-specular modes within the same framework. In particular, the depth and lateral distribution of the ferromagnetic spins relative to the interface within interlayercoupled or exchange-coupled system has been extensive. For example, twisted magnetization state at interlayer coupled interfaces or intricacies of symmetric and asymmetric magnetization reversals along with suppression of training effect in exchange coupled system was microscopically identified using neutron scattering only. The investigation on the distribution of magnetic species within dilute ferromagnetic semiconductor superlattices, with low angle neutron scattering, has played a crucial role both from practical and fundamental research points of view.

  2. Monte Carlo analysis of accelerator-driven systems studies on spallation neutron yield and energy gain

    CERN Document Server

    Hashemi-Nezhad, S R; Westmeier, W; Bamblevski, V P; Krivopustov, M I; Kulakov, B A; Sosnin, A N; Wan, J S; Odoj, R

    2001-01-01

    The neutron yield in the interaction of protons with lead and uranium targets has been studied using the LAHET code system. The dependence of the neutron multiplicity on target dimensions and proton energy has been calculated and the dependence of the energy amplification on the proton energy has been investigated in an accelerator-driven system of a given effective multiplication coefficient. Some of the results are compared with experimental findings and with similar calculations by the DCM/CEM code of Dubna and the FLUKA code system used in CERN. (14 refs).

  3. Development of the JAERI computational dosimetry system (JCDS) for boron neutron capture therapy. Cooperative research

    CERN Document Server

    Kumada, H; Matsumura, A; Nakagawa, Y; Nose, T; Torii, Y; Uchiyama, J; Yamamoto, K; Yamamoto, T

    2003-01-01

    The Neutron Beam Facility at JRR-4 enables us to carry out boron neutron capture therapy with epithermal neutron beam. In order to make treatment plans for performing the epithermal neutron beam BNCT, it is necessary to estimate radiation doses in a patient's head in advance. The JAERI Computational Dosimetry System (JCDS), which can estimate distributions of radiation doses in a patient's head by simulating in order to support the treatment planning for epithermal neutron beam BNCT, was developed. JCDS is a software that creates a 3-dimentional head model of a patient by using CT and MRI images, and that generates a input data file automatically for calculation of neutron flux and gamma-ray dose distributions in the brain with the Monte Carlo code MCNP, and that displays these dose distributions on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By using CT data and MRI data which are medical images, a detail three-dimensional model of patient's head is...

  4. Time-dependent thermal neutron field in two-region bounded systems

    International Nuclear Information System (INIS)

    A set of solutions of the time-dependent diffusion equation for two-region bounded systems in spherical and cylindrical geometries is presented. Two types of solutions are given for each geometry: the general solution and a solution for the case where the spatial distribution of the thermal neutron flux is constant inside the inner region. These solutions provide the theoretical background for the development of a new method of measuring the thermal neutron macroscopic absorption cross section. The theoretical description of the method worked out for small samples is in good agreement with the experimental results presented. The principles of measuring the neutron transport cross section using small samples and mathematical solutions are described. The possibility of applying a sinusoidally modulated neutron source is presented. Special attention is paid to proper averaging of the thermal neutron diffusion parameters and to the problem of boundary effects. The so-called thermal neutron average dynamic parameters have been used. Results obtained from the modified diffusion theory compare satisfactorily with those obtained form the one-speed transport and P3 theory approximations. (au) (56 refs.)

  5. Radiation damage and waste management options for the sombrero final focus system and neutron dumps

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, S.; Latkowski, J.F.; Meier, W.R. [Lawrence Livermore National Lab., CA (United States); Reyes, S. [Escuela Tecnica Superior de Ingenieros Industriales, Universidad Nacional de Educacion a Distancia and Instituto de Fusion Nuclear, Dept. Ingenieria Energetica, Bilbao (Spain)

    2000-07-01

    Previous studies of the safety and environmental aspects of the SOMBRERO inertial fusion energy (IFE) power plant design did not completely address the issues associated with the final focus system. While past work calculated neutron fluences for a grazing incidence metal mirror (GIMM) and a final focus mirror, scattering off of the final optical component was not included, and thus, fluences in the final focus mirror were significantly underestimated. In addition, past work did not consider neutron-induced gamma-rays. Finally, power plant lifetime waste volumes may have been underestimated as neutron activation of the neutron dumps and building structure were not addressed. In the present work, a modified version of the SOMBRERO target building is presented where a significantly larger open solid-angle fraction (5%) is used to enhance beam smoothing of a diode-pumped solid-state laser (DPSSL). The GIMMs are replaced with transmissive fused silica wedges and have been included in three-dimensional neutron and photon transport calculations. This work shows that a power plant with a large open solid-angle fraction, needed for beam smoothing with a DPSSL, is acceptable from tritium breeding, and neutron activation points-of-view. (authors)

  6. Neutron dosimetry in containment of a pressurized water reactor utilizing the Panasonic UD-802 dosimetry system

    International Nuclear Information System (INIS)

    The Panasonic UD-802 dosimeter was evaluated as a potential neutron dosimeter for use in containment of a PWR. The Panasonic UD-802 dosimeter, although designed as a beta and gamma dosimeter, is also sensitive to neutrons. UD-802 dosimeters were mounted on polyethylene phantoms and irradiated to known doses at selected locations in containment. The known neutron dose equivalents were determined based on remmeter dose rate measurements and stay times. The thermoluminescent response of the dosimeters and the known neutron dose equivalents were used to obtain a calibration factor at each location. The average calibration factor was 3.7 (unit of dosimeter response per mrem) and all calibration factors were within +-30% of this mean value. The dosimeter distance from the phantom was found to have minimal effect on the response but the system was directionally dependent, necessitating a correction in the calibration factor. The minimum significant dosimeter response was determined independent of any calibration factor. The minimum significant response of the UD-802 to neutrons is a function of the corresponding gamma exposure rate. It is concluded that the Panasonic UD-802 dosimeter can be used for neutron dosimetry in PWR containment

  7. Implementation of the neutron noise technique for subcritical reactors using a new data acquisition system

    International Nuclear Information System (INIS)

    A new data acquisition system was designed and programmed for nuclear kinetics parameter estimations in subcritical reactors. The system allows using any of the neutron noise techniques, since it could store the whole information available in the neutron detection system. The α Rossi, α Feynman and spectral analysis methods were performed in order to estimate the prompt neutron decay constant (and hence the reactivity). The measurements were done in the nuclear research reactor RA-1, where introducing the control rods, different reactivity levels where reached (until -7 dollars). With the three methods used, agreement was found between the estimations and the reference reactivities in each level, even when the detector efficiency was low. All the measurements were performed with a high gamma flux, although the results were found to be satisfactory. (author)

  8. Development on New Style of Drummed Nuclear Waste Neutron Counting System

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Designing a new style of drummed nuclear waste neutron counting system (WNC) was carried out in 2011. 3He proportional tubes are used as detector in this system. According to the limited quantity of 3He tubes, Monte Carlo method is used for

  9. A prototype vector magnetic field monitoring system for a neutron electric dipole moment experiment

    CERN Document Server

    Nouri, N; Brown, M A; Carr, R; Filippone, B; Osthelder, C; Plaster, B; Slutsky, S; Swank, C

    2015-01-01

    We present results from a first demonstration of a magnetic field monitoring system for a neutron electric dipole moment experiment. The system is designed to reconstruct the vector components of the magnetic field in the interior measurement region solely from exterior measurements.

  10. Fissile analysis of Hanford waste using Californium Multiplier/Delayed Neutron Counter system

    International Nuclear Information System (INIS)

    Measurement of low-level (10 ng/g or lower) fissile material (mainly plutonium) in Hanford waste and process samples is becoming increasingly important. A system has been designed consisting of a Californium Multiplier (CFX) and a Delayed Neutron Counter (DNC) to characterize these samples. This report describes hardware and analytical capability of the CFX/DNC system

  11. A novel type epithermal neutron radiography detecting and imaging system

    CERN Document Server

    Balasko, M; Svab, E; Eoerdoegh, I

    1999-01-01

    The transfer technique is widely used for epithermal neutron radiography (ENR) for making images upon the object to be investigated. We propose to use instead of the photosensitive film a gamma sensitive scintillation screen (NaCe single crystal), that is monitored by a computer controlled low light level TV camera. The exposure time has been reduced to a duration of only a short fraction of that needed for the conventional transfer process. The presented ENR images consist of electronic signals that are handled by an advanced image processing and analyzing program, the Iman 1.4 version, using a task oriented video grabber.

  12. Penumbral imaging and numerical evaluation of large area source neutron imaging system

    Institute of Scientific and Technical Information of China (English)

    WU YueLei; HU HuaSi; ZHANG BoPing; LI LinBo; CHEN Da; SHAN Qing; ZHU Jie

    2009-01-01

    The fusion neutron penumbral imaging system Monte Carlo model was established. The transfer func-tions of the two discrete units in the neutron source were obtained in two situations: Imaging in geo-metrical near-optical and real situation. The spatial resolutions of the imaging system in two situations were evaluated and compared. The penumbral images of four units in the source were obtained by means of 2-dimensional (2D) convolution and Monte Carlo simulation. The penumbral images were reconstructed with the same method of filter. The same results were confirmed. The encoding essence of penumbral imaging was revealed. With MCNP(Monte Carlo N-particle) simulation, the neutron pen-umbral images of the large area source (200 μm×200 μm) on scintillation fiber array were obtained. The improved Wiener filter method was used to reconstruct the penumbral image and the source image was obtained. The results agree with the preset neutron source image. The feasibility of the neutron imaging system was verified.

  13. PGNAA system preliminary design and measurement of In-Hospital Neutron Irradiator for boron concentration measurement.

    Science.gov (United States)

    Zhang, Zizhu; Chong, Yizheng; Chen, Xinru; Jin, Congjun; Yang, Lijun; Liu, Tong

    2015-12-01

    A prompt gamma neutron activation analysis (PGNAA) system has been recently developed at the 30-kW research reactor In-Hospital Neutron Irradiator (IHNI) in Beijing. Neutrons from the specially designed thermal neutron beam were used. The thermal flux of this beam is 3.08×10(6) cm(-2) s(-1) at a full reactor power of 30 kW. The PGNAA system consists of an n-type high-purity germanium (HPGe) detector of 40% efficiency, a digital spectrometer, and a shielding part. For both the detector shielding part and the neutron beam shielding part, the inner layer is composed of (6)Li2CO3 powder and the outer layer lead. The boron-10 sensitivity of the PGNAA system is approximately 2.5 cps/ppm. Two calibration curves were produced for the 1-10 ppm and 10-50 ppm samples. The measurement results of the control samples were in accordance with the inductively coupled plasma atomic emission spectroscopy (ICP-AES) results. PMID:26242556

  14. Penumbral imaging and numerical evaluation of large area source neutron imaging system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The fusion neutron penumbral imaging system Monte Carlo model was established. The transfer functions of the two discrete units in the neutron source were obtained in two situations:Imaging in geometrical near-optical and real situation. The spatial resolutions of the imaging system in two situations were evaluated and compared. The penumbral images of four units in the source were obtained by means of 2-dimensional (2D) convolution and Monte Carlo simulation. The penumbral images were reconstructed with the same method of filter. The same results were confirmed. The encoding essence of penumbral imaging was revealed. With MCNP(Monte Carlo N-particle) simulation,the neutron penumbral images of the large area source (200 μm×200 μm) on scintillation fiber array were obtained. The improved Wiener filter method was used to reconstruct the penumbral image and the source image was obtained. The results agree with the preset neutron source image. The feasibility of the neutron imaging system was verified.

  15. Neutronic study of an innovative natural uranium–thorium based fusion–fission hybrid energy system

    International Nuclear Information System (INIS)

    Highlights: • An innovative fusion-fission hybrid reactor blanket design is presented. • The blanket adopts seed–blanket concept to improve overall neutron economy. • The blanket is designed with two types of modules, i.e. uranium and thorium module. • The reactor could reach multi operating system purpose. - Abstract: An innovative design for a water cooled fusion–fission hybrid reactor (FFHR), aiming at efficiently utilizing natural uranium and thorium resources, is presented. The major objective is to study the feasibility of this concept balanced with multi-purposes, including energy gain, tritium breeding and 233U breeding. In order to improve overall neutron economy of the system, the fission blanket is designed with two types of modules, i.e. the natural uranium modules (U-modules) and thorium modules (Th-modules), which are alternately arranged in the toroidal and poloidal directions of the blanket. This innovative design is based on a simple intuition of neutron distribution: with the alternate geometrical arrangement, energy multiplication by uranium fission, tritium breeding and 233U breeding are performed separately in different sub-zones in the blanket. The uranium modules which has excellent neutron economy under the combined neutron spectrum, plays the dominant role in the energy production, neutron multiplication and tritium breeding. Excess neutrons produced by the uranium modules are then used to drive the thorium modules (which have poor neutron economy) to breed 233U fuel. Therefore, it creates a new free dimension to realize the blanket’s balanced design. The COUPLE code developed by INET of Tsinghua University is used to simulate the neutronic behavior in the blanket. The simulated results show that with the volumetric ratio of thorium modules about 0.4, the balanced design for multi purposes is achievable, with energy multiplication M ⩾ 9, tritium breeding ratio TBR ⩾ 1.05, and at the end of the five years refueling cycle

  16. On formation of the asymptotic spectrum of delayed neutron emitters in measuring the VVER-1000 scram system effectiveness

    Science.gov (United States)

    Shishkov, L. K.; Zizin, M. N.

    2014-12-01

    The process of formation of an asymptotic distribution of the neutron flux density in the reactor systems after introducing different negative reactivities is considered. The impact of two factors after the reactivity introduction is evaluated: (1) nonuniformity of perturbation of core properties, on one hand, and (2) a sharp reduction in the density of prompt neutrons, which prevents the appearance of new delayed neutron emitters distributed in accordance with the "new" prompt neutron distribution, on the other hand. The results of calculations show that the errors of measuring the scram system effectiveness using the method of inverse solution of the kinetics equation are caused by the fact that, after the negative reactivity insertion, the sources of prompt and delayed neutrons have different spatial distributions. In the case of high negative reactivities, this difference remains while the system still has neutrons, which can be measured.

  17. FOCUS, Neutron Transport System for Complex Geometry Reactor Core and Shielding Problems by Monte-Carlo

    International Nuclear Information System (INIS)

    1 - Description of problem or function: FOCUS enables the calculation of any quantity related to neutron transport in reactor or shielding problems, but was especially designed to calculate differential quantities, such as point values at one or more of the space, energy, direction and time variables of quantities like neutron flux, detector response, reaction rate, etc. or averages of such quantities over a small volume of the phase space. Different types of problems can be treated: systems with a fixed neutron source which may be a mono-directional source located out- side the system, and Eigen function problems in which the neutron source distribution is given by the (unknown) fundamental mode Eigen function distribution. Using Monte Carlo methods complex 3- dimensional geometries and detailed cross section information can be treated. Cross section data are derived from ENDF/B, with anisotropic scattering and discrete or continuous inelastic scattering taken into account. Energy is treated as a continuous variable and time dependence may also be included. 2 - Method of solution: A transformed form of the adjoint Boltzmann equation in integral representation is solved for the space, energy, direction and time variables by Monte Carlo methods. Adjoint particles are defined with properties in some respects contrary to those of neutrons. Adjoint particle histories are constructed from which estimates are obtained of the desired quantity. Adjoint cross sections are defined with which the nuclide and reaction type are selected in a collision. The energy after a collision is selected from adjoint energy distributions calculated together with the adjoint cross sections in advance of the actual Monte Carlo calculation. For multiplying systems successive generations of adjoint particles are obtained which will die out for subcritical systems with a fixed neutron source and will be kept approximately stationary for Eigen function problems. Completely arbitrary problems can

  18. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N.N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  19. Monte Carlo simulation of the neutron guide system for the SNS engineering diffractometer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.L.; Lee, W.T. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2001-03-01

    VULCAN, the SNS engineering diffractometer, is designed to tackle a broad range of engineering problems, from residual stress distribution in components to materials response under loading. In VULCAN, neutrons are delivered to the sample position via a series of straight and curved neutron guides. An interchangeable guide-collimator system is planned in the incident beam path, allowing the instrument to be optimally configured for individual experiments with different intensity-resolution requirements. To achieve maximum data rate and large d-spacing coverage, detectors are employed continuously from 60deg to 150deg in the horizontal scattering plane and -30deg to 30deg in the vertical plane. To enable simultaneous small angle scattering measurements for characterization of the microstructure, the instrument is also equipped with a position sensitive area detector. Monte Carlo simulation indicates that the proposed neutron guide system is able to deliver the desired intensity and resolution. (author)

  20. Multi-Frame Energy-Selective Imaging System for Fast-Neutron Radiography

    CERN Document Server

    Dangendorf, Volker; Bromberger, Benjamin; Feldman, Gennady; Goldberg, Mark B; Lauck, Ronald; Mor, Ilan; Tittelmeier, Kai; Vartsky, David; Weierganz, Mathias

    2009-01-01

    A new instrument for high resolution imaging of fast-neutrons is presented here. It is designed for energy selective radiography in nanosecond-pulsed broad-energy (1 - 10 MeV) neutron beams. The device presented here is based on hydrogenous scintillator screens and single- or multiple-gated intensified camera systems (ICCD). A key element is a newly developed optical amplifier which generates sufficient light for the high-speed intensified camera system, even from such faint light sources as fast plastic and liquid scintillators. Utilizing the Time-of-Flight (TOF) method, the detector incorporating the above components is capable of simultaneously taking up to 8 images, each at a different neutron energy.

  1. Multi-Frame Energy-Selective Imaging System for Fast-Neutron Radiography

    Science.gov (United States)

    Dangendorf, Volker; Bar, Doron; Bromberger, Benjamin; Feldman, Gennady; Goldberg, Mark Benjamin; Lauck, Ronald; Mor, Ilan; Tittelmeier, Kai; Vartsky, David; Weierganz, Mathias

    2009-06-01

    A new instrument for high resolution imaging of fast-neutrons is presented here. It is designed for energy selective radiography in nanosecond-pulsed broad-energy (1 - 10 MeV) neutron beams. The device presented here is based on hydrogenous scintillator screens and single- or multiple-gated intensified camera systems (ICCD). A key element is a newly developed optical amplifier which generates sufficient light for the high-speed intensified camera system, even from such faint light sources as fast plastic and liquid scintillators. Utilizing the Time-of-Flight (TOF) method, the detector incorporating the above components is capable of simultaneously taking up to 8 images, each at a different neutron energy.

  2. COLLI-PTB, Neutron Fluence Spectra for 3-D Collimator System by Monte-Carlo

    International Nuclear Information System (INIS)

    1 - Description of program or function: For optimizing collimator systems (shieldings) for fast neutrons with energies between 10 KeV and 20 MeV. Only elastic and inelastic neutron scattering processes are involved. Isotropic angular distribution for inelastic scattering in the center of mass system is assumed. 2 - Method of solution: The Monte Carlo method with importance sampling technique, splitting and Russian Roulette is used. The neutron attenuation and scattering kinematics is taken into account. 3 - Restrictions on the complexity of the problem: Energy range from 10 KeV to 20 MeV. For the output spectra any bin width is possible. The output spectra are confined to 40 equidistant channels

  3. Radiological risks from irradiation of cargo contents with EURITRACK neutron inspection systems

    International Nuclear Information System (INIS)

    The radiological risk for the population related to the neutron irradiation of cargo containers with a tagged neutron inspection system has been studied. Two possible effects on the public health have been assessed: the modification of the nutritional and organoleptic properties of the irradiated materials, in particular foodstuff, and the neutron activation of consumer products (i.e. food and pharmaceuticals). The result of this study is that irradiation of food and foodstuff, pharmaceutical and medical devices in container cargoes would neither modify the properties of the irradiated material nor produce effective doses of concern for public health. Furthermore, the dose received by possible stowaways present inside the container during the inspection is less than the annual effective dose limit defined by European Legislation for the public. - Highlights: ► Neutron irradiation of cargo containers implies a radiological risk. ► The risk is about the modification of food properties and the products activation. ► Assessment is made about the EURITRACK neutron irradiation system. ► Results show that the EURITRACK scanning is not dangerous for the population.

  4. Present status of fast neutron personnel dosimetry system based on CR-39 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Neutron sources are of different types depending upon the method of production such as nuclear reactors, particle accelerators and laboratory sources. Neutron sources depending upon their energy, flux, size etc. are used for variety of applications in basic and applied sciences, neutron scattering experiments and in industry such as oil well - digging, coal mining and processing, ore processing etc. Personnel working in nuclear installations such as reactors, accelerators, spent fuel processing plants, nuclear fuel cycle operations and those working in various industries such as oil refining, oil well-digging, coal mining and processing, ore processing, etc. need to be monitored for neutron exposures, if any. Neutron monitoring is especially necessary in view of the fact that the radiation weighting factor for neutron is much higher than gamma rays and also it varies with energy. Radiological Physics and Advisory Division is involved in monitoring of personnel working in neutron fields. Around 2100 workers from 70 institutions (DAE and Non-DAE) are monitored on a quarterly basis. Neutron personnel monitoring, carried out in the country is based on Solid State Nuclear Track Detection (SSNTD) technique. In this technique, neutrons interact with hydrogen in CR-39 polymer to produce recoil protons. These protons create damages in the polymer, which are enlarged and appear as tracks when subjected to electrochemical etching (ECE). These tracks are counted in an optical system to evaluate the neutron dose. The neutron dosimetry system based on SSNTD has undergone a significant development, since it was started in 1990. The development includes upgradation of image analysis system for counting tracks, introduction of chemical etching (CE) at elevated temperatures for evaluation of dose equivalents above 10 mSv and use of carbon laser for cutting of CR-39 detectors. The entire dose evaluation process has been standardized, which includes calibration and performance tests

  5. Performance analysis of a neutron and X-ray combined computed tomography system

    International Nuclear Information System (INIS)

    A novel neutron and X-ray combined computed tomography system (NXCT) has been developed at the Missouri University of Science and Technology. It is believed that it will provide a superior method for non-destructive testing and evaluation. The system is housed within the Missouri University of Science and Technology Reactor (MSTR) and is the first such imaging platform and synthesis method to be developed. The system utilizes neutrons obtained directly from the reactor core and X-rays from an X-ray generator. Characterization of the newly developed digital imaging system is imperative to the performance evaluation, as well as for describing the associated parameters. The preliminary evaluation of the NXCT system was performed in terms of image uniformity, linearity and spatial resolution. Additionally, the correlation between the applied beam intensity, the resulting image quality, and the system sensitivity was investigated. The combined neutron/X-ray digital imaging system was evaluated in terms of performance parameters and results are detailed. The Modulation Transfer Function (MTF) of the X-ray imaging module was calculated using the Edge method. The spatial frequency at 10% of the MTF was found to be 8 l p/mm, which is in agreement with the value of 8.5 l p/mm determined from the square wave response method. The highest detective quantum efficiency of the X-ray imaging module was found to be 0.53. Furthermore, the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE) spectrum for the neutron imaging module was also evaluated in a similar way as the X-ray imaging module. In order to improve the image quality of the neutron imaging module, a pin-hole mask phantom was used to correct the geometrical non-linearity of the delay line anode readout. The non-linearity correction of the delay line anode readout has been shown through the corrected images of perforated cadmium strip and electroformed phantom

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

    International Nuclear Information System (INIS)

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

  7. Neutron interferometer as a device for illustrating the strange behavior of quantum systems

    International Nuclear Information System (INIS)

    The neutron interferometer is a unique instrument that allows one to construct a neutron wave packet of macroscopic size, divide it into two components separated by centimeters, and then coherently recombine them. A number of experiments clearly showing the difference between quantum and classical theory have been performed with it, which are suitable for presentation in elementary quantum courses. This article presents a simple mathematical model of the interferometer, which can be used to illustrate clearly many of the surprising features of quantum systems. For example, one can describe an experiment to determine which component beam the neutron takes (an analog of the two-slit electron experiment). One can then trace in detail the loss of coherence of the wave function, rather than merely invoke the usual ''handwaving'' uncertainty arguments. The author discusses the effect of gravity on the neutron beam [the classic COW (Colella, Overhauser, and Werner) experiment], including a simple analysis in an accelerated reference frame, and its relation to the equivalence principle, the red shift, and the twin paradox. Also described are the effect of rotation of the neutron by 3600 to change its phase, the effect on the wave function of measuring the absence of the particle from a beam (''Dicke's paradox''), and a realizable version of Wheeler's ''delayed-choice'' experiments, as well as their relation to the problem of ''Schroedinger's cat.'' The treatment is suitable for bright undergraduates and first-year graduate students

  8. Mercury as a target material for pulsed (fast) spallation neutron sources systems

    International Nuclear Information System (INIS)

    For spallation neutron systems which are not adversely affected by the high thermal absorption cross section, mercury seems to be a good target material because it is liquid at ambient temperatures, shows good compatibility with low nickel content steels, has a high neutron yield, is easy to purify and has no truly long lived isotopes. Its performance in an engineered target for pulsed spallation sources is expected to be superior to that of its solid competitors Ta and W and equivalent to that of Pb or Pb-Bi but at much less overall technical effort. (author) 5 figs., 5 tabs., 11 refs

  9. Measurements of neutron cross sections for advanced nuclear energy systems at n_TOF (CERN

    Directory of Open Access Journals (Sweden)

    Barbagallo M.

    2014-03-01

    Full Text Available The n_TOF facility operates at CERN with the aim of addressing the request of high accuracy nuclear data for advanced nuclear energy systems as well as for nuclear astrophysics. Thanks to the features of the neutron beam, important results have been obtained on neutron induced fission and capture cross sections of U, Pu and minor actinides. Recently the construction of another beam line has started; the new line will be complementary to the first one, allowing to further extend the experimental program foreseen for next measurement campaigns.

  10. Some neutron absorbing elements and devices for fast nuclear reactors regulation systems

    International Nuclear Information System (INIS)

    It is shown that performed technological, physical-mechanical and radiation tests clearly indicate the prospects of using Neutron Absorbing Elements (NAE) based on B-10 and some rare-earth compounds during the creation of highly effective Control and Safety System (CSS) rods for fast neutron nuclear energetic reactors. Particular attention was paid to the development of new and upgrading of existing computing and real technologies for designing and preparing the optimizing NAE items characterized by all physical and strength properties for obtaining desirable operational parameters of CSS rods on their base

  11. POW3D-Neutron diffusion module of the AUS system. A user`s manual

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, B.V.; Pollard, J.P.; Barry, J.M.

    1996-11-01

    POW3D is a three-dimensional neutron diffusion module of the AUS modular neutronics code system. It performs eigenvalue, source of feedback-free kinetics calculations. The module includes general criticality search options and extensive editing facilities including perturbation calculations. Output options include flux or reaction rate plot files. The code permits selection from one of a variety of different solution methods (MINI, ICCG or SLOR) for inner iterations with region re balance to enhance convergence. A MINI accelerated Gauss-Siedel method is used for upscatter iterations with group rebalance to enhance a convergence. Chebyshev source extrapolation is applied for outer iterations. A detailed index is included.

  12. 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.

  13. The application of a NaI(Tl) detector system for measuring neutrons with capturing method

    International Nuclear Information System (INIS)

    The NaI(Tl) detector and the lead-shielding chamber used to measure neutron with capturing method were introduced. The detector system was applied in the experiment. The γ rays from the capturing foils was measured. The performance of the capturing detector was studied

  14. AUS98 - The 1998 version of the AUS modular neutronic code system

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, G.S.; Harrington, B.V

    1998-07-01

    AUS is a neutronics code system which may be used for calculations of a wide range of fission reactors, fusion blankets and other neutron applications. The present version, AUS98, has a nuclear cross section library based on ENDF/B-VI and includes modules which provide for reactor lattice calculations, one-dimensional transport calculations, multi-dimensional diffusion calculations, cell and whole reactor burnup calculations, and flexible editing of results. Calculations of multi-region resonance shielding, coupled neutron and photon transport, energy deposition, fission product inventory and neutron diffusion are combined within the one code system. The major changes from the previous AUS publications are the inclusion of a cross-section library based on ENDF/B-VI, the addition of the MICBURN module for controlling whole reactor burnup calculations, and changes to the system as a consequence of moving from IBM main-frame computers to UNIX workstations This report gives details of all system aspects of AUS and all modules except the POW3D multi-dimensional diffusion module refs., tabs.

  15. Research of the system response of neutron double scatter imaging for MLEM reconstruction

    International Nuclear Information System (INIS)

    A Maximum Likelihood image reconstruction technique has been applied to neutron scatter imaging. The response function of the imaging system can be obtained by Monte Carlo simulation, which is very time-consuming if the number of image pixels and particles is large. In this work, to improve time efficiency, an analytical approach based on the probability of neutron interaction and transport in the detector is developed to calculate the system response function. The response function was applied to calculate the relative efficiency of the neutron scatter imaging system as a function of the incident neutron energy. The calculated results agreed with simulations by the MCNP5 software. Then the maximum likelihood expectation maximization (MLEM) reconstruction method with the system response function was used to reconstruct data simulated by Monte Carlo method. The results showed that there was good consistency between the reconstruction position and true position. Compared with back-projection reconstruction, the improvement in image quality was obvious, and the locations could be discerned easily for multiple radiation point sources

  16. Design and layout decision for refueling system of advanced fast neutron reactors

    International Nuclear Information System (INIS)

    Describes fast neutron reactor refueling features, BN-1200 power unit general data, its refueling system design concepts, individual refueling equipment purpose and designs, and required experimental studies to create it. Refueling equipment characteristics for BN-800 and BN-1200 reactors are compared. (author)

  17. Radiological risks from irradiation of cargo contents with EURITRACK neutron inspection systems

    Science.gov (United States)

    Giroletti, E.; Bonomi, G.; Donzella, A.; Viesti, G.; Zenoni, A.

    2012-07-01

    The radiological risk for the population related to the neutron irradiation of cargo containers with a tagged neutron inspection system has been studied. Two possible effects on the public health have been assessed: the modification of the nutritional and organoleptic properties of the irradiated materials, in particular foodstuff, and the neutron activation of consumer products (i.e. food and pharmaceuticals). The result of this study is that irradiation of food and foodstuff, pharmaceutical and medical devices in container cargoes would neither modify the properties of the irradiated material nor produce effective doses of concern for public health. Furthermore, the dose received by possible stowaways present inside the container during the inspection is less than the annual effective dose limit defined by European Legislation for the public.

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

    Science.gov (United States)

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

    2016-05-01

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

  19. Acceleration of criticality analysis solution convergence by matrix eigenvector for a system with weak neutron interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Yasushi; Takada, Tomoyuki; Kuroishi, Takeshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kadotani, Hiroyuki [Shizuoka Sangyo Univ., Iwata, Shizuoka (Japan)

    2003-03-01

    In the case of Monte Carlo calculation to obtain a neutron multiplication factor for a system of weak neutron interaction, there might be some problems concerning convergence of the solution. Concerning this difficulty in the computer code calculations, theoretical derivation was made from the general neutron transport equation and consideration was given for acceleration of solution convergence by using the matrix eigenvector in this report. Accordingly, matrix eigenvector calculation scheme was incorporated together with procedure to make acceleration of convergence into the continuous energy Monte Carlo code MCNP. Furthermore, effectiveness of acceleration of solution convergence by matrix eigenvector was ascertained with the results obtained by applying to the two OECD/NEA criticality analysis benchmark problems. (author)

  20. Analysis of a measured neutron background below 6 MeV for fast-neutron imaging systems

    International Nuclear Information System (INIS)

    Detailed and accurate information on the neutron background is relevant for many applications that involve radiation detection, both for non-coincidence and coincidence countings. In particular, for the purpose of developing advanced neutron-detection techniques for nuclear non-proliferation and nuclear safeguards, the energy-dependent, ground-level, neutron-background information is needed. There are only a few previous studies available about the neutron background below 10 MeV, which is a typical neutron energy range of interest for nuclear non-proliferation and nuclear-safeguards applications. Thus, there is a potential for further investigation in this energy range. In this paper, neutron-background measurement results using organic-liquid scintillation detectors are described and discussed, with a direct application in optimization simulations of a fast-neutron imager based on liquid scintillators. The measurement was performed in summer 2011 in Ann Arbor, Michigan, USA, and the measurement setup consisted of several EJ-309 liquid scintillators and a fast waveform digitizer. The average neutron flux below 6 MeV was measured to be approximately 4e−4 counts/cm2/s. In addition, the relationship between the neutron-background count rate and various environmental quantities, such as humidity, at Earth's ground level was investigated and the results did not reveal any straightforward dependences. The measured pulse height distribution (PHD) was unfolded to determine the energy spectrum of the background neutrons. The unfolded neutron-background spectrum was implemented to a previously-created MCNPX-PoliMi model of the neutron-scatter camera and simple-backprojection images of the background neutrons were acquired. Furthermore, a simulated PHD was obtained with the MCNPX-PoliMi code using the “Cosmic-Ray Shower Library” (CRY) source sub-routine which returns various types of radiation, including neutrons and photons at a surface, and accounts for solar cycle

  1. Design, testing and optimization of a neutron radiography system based on a Deuterium-Deuterium (D-D) neutron generator

    International Nuclear Information System (INIS)

    Simulations show that significant improvement in imaging performance can be achieved through collimator design for thermal and fast neutron radiography with a laboratory neutron generator. The radiography facility used in the measurements and simulations employs a fully high-voltage-shielded, axial D–D neutron generator with a radio frequency driven ion source. The maximum yield of such generators is about 1010 fast neutrons per seconds (E = 2.45 MeV). Both fast and thermal neutron images were acquired with the generator and a Charge Coupled Devices camera. To shorten the imaging time and decrease the noise from gamma radiation, various collimator designs were proposed and simulated using Monte Carlo N-Particle Transport Code (MCNPX 2.7.0). Design considerations included the choice of material, thickness, position and aperture for the collimator. The simulation results and optimal configurations are presented. (author)

  2. Development of the JAERI computational dosimetry system (JCDS) for boron neutron capture therapy. Cooperative research

    Energy Technology Data Exchange (ETDEWEB)

    Kumada, Hiroaki; Yamamoto, Kazuyoshi; Torii, Yoshiya; Uchiyama, Junzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Matsumura, Akira; Yamamoto, Tetsuya; Nose, Tadao [Tsukuba Univ., Tsukuba, Ibaraki (Japan); Nakagawa, Yoshinobu [National Sanatorium Kagawa-Children' s Hospital, Kagawa (Japan); Kageji, Teruyoshi [Tokushima Univ., Tokushima (Japan)

    2003-03-01

    The Neutron Beam Facility at JRR-4 enables us to carry out boron neutron capture therapy with epithermal neutron beam. In order to make treatment plans for performing the epithermal neutron beam BNCT, it is necessary to estimate radiation doses in a patient's head in advance. The JAERI Computational Dosimetry System (JCDS), which can estimate distributions of radiation doses in a patient's head by simulating in order to support the treatment planning for epithermal neutron beam BNCT, was developed. JCDS is a software that creates a 3-dimentional head model of a patient by using CT and MRI images, and that generates a input data file automatically for calculation of neutron flux and gamma-ray dose distributions in the brain with the Monte Carlo code MCNP, and that displays these dose distributions on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By using CT data and MRI data which are medical images, a detail three-dimensional model of patient's head is able to be made easily. The three-dimensional head image is editable to simulate the state of a head after its surgical processes such as skin flap opening and bone removal in the BNCT with craniotomy that are being performed in Japan. JCDS can provide information for the Patient Setting System which can support to set the patient to an actual irradiation position swiftly and accurately. This report describes basic design of JCDS and functions in several processing, calculation methods, characteristics and performance of JCDS. (author)

  3. 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

  4. High Speed Data Acquisition System for Three-Dimensional X-Ray and Neutron Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Davis, A.W.; Claytor, T.N.; Sheats, M.J.

    1999-07-01

    Computed tomography for nondestructive evaluation applications has been limited by system cost, resolution, and time requirements for three-dimensional data sets. FlashCT (Flat panel Amorphous Silicon High-Resolution Computed Tomography) is a system developed at Los Alamos National Laboratory to address these three problems. Developed around a flat panel amorphous silicon detector array, FlashCT is suitable for low to medium energy x-ray and neutron computed tomography at 127-micron resolution. Overall system size is small, allowing rapid transportation to a variety of radiographic sources. System control software was developed in LabVIEW for Windows NT to allow multithreading of data acquisition, data correction, and staging motor control. The system control software simplifies data collection and allows fully automated control of the data acquisition process, leading toward remote or unattended operation. The first generation of the FlashCT Data Acquisition System was completed in Au gust 1998, and since that time the system has been tested using x-ray sources ranging in energy from 60 kV to 20MV. The system has also been used to collect data for thermal neutron computed tomography at Los Alamos Neutron Science Center (LANSCE). System improvements have been proposed to provide faster data collection and greater dynamic range during data collection.

  5. Assessment of the reliability of neutronic parameters of Ghana Research Reactor-1 control systems

    Energy Technology Data Exchange (ETDEWEB)

    Amponsah-Abu, E.O., E-mail: edwardabu2002@yahoo.com [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG. 80, Legon-Accra (Ghana); Gbadago, J.K. [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG. 80, Legon-Accra (Ghana); Akaho, E.H.K.; Akoto-Bamford, S. [School of Nuclear and Allied Sciences, University of Ghana (Ghana); Gyamfi, K.; Asamoah, M.; Baidoo, I.K. [National Nuclear Research Institute, Ghana Atomic Energy Commission, P.O. Box LG. 80, Legon-Accra (Ghana)

    2015-01-15

    Highlights: • The reliability of neutronics parameters of GHARR-I was assessed. • The reactor was operated at different power levels of 5–30 kW. • The pre-set flux was compared with the flux in the inner irradiation site. • Decrease in the core reactivity caused difference in flux on the meters and site. • Neutronic parameters become reliable when operation is done at reactivity of 4 mk. - Abstract: The Ghana Research Reactor-1 (GHARR-1) has been in operation for the past 19 years using a Micro-Computer Closed Loop System (MCCLS) and Control Console (CC) as the control systems. The two control systems were each coupled separately with a micro-fission chamber to measure the current pulses of the neutron fluxes in the core at excess reactivity of 4 mk. The MCCLS and CC meter readings at a pre-set flux of 5.0 × 10{sup 11} n/cm{sup 2} s were 6.42 × 10{sup 11} n/cm{sup 2} s and 5.0 × 10{sup 11} n/cm{sup 2} s respectively. Due to ageing and obsolescence, the MCCLS and some components that control the sensitivity and the reading mechanism of the meters were replaced. One of the fission chambers was also removed and the two control systems were coupled to one fission chamber. The reliability of the neutronic parameters of the control systems was assessed after the replacement. The results showed that when the reactor is operated at different power levels of 5–30 kW using one micro-fission chamber, the pre-set neutron fluxes at the control systems is 1.6 times the neutron fluxes obtained using a flux monitor at the inner irradiation site two of the reactor. The average percentage deviations of the obtained fluxes from the pre-set values of 1.67 × 10{sup 11}–1.0 × 10{sup 12} n/cm{sup 2} s were 36.5%. This compares very well with the decrease in core excess reactivity of 36.3% of the nominal value of 4 mk, after operating the reactor at critical neutron flux of 1.0 × 10{sup 9} n/cm{sup 2} s.

  6. Gadolinium-doped water cerenkov-based neutron and high energy gamma-ray detector and radiation portal monitoring system

    Science.gov (United States)

    Dazeley, Steven A; Svoboda, Robert C; Bernstein, Adam; Bowden, Nathaniel

    2013-02-12

    A water Cerenkov-based neutron and high energy gamma ray detector and radiation portal monitoring system using water doped with a Gadolinium (Gd)-based compound as the Cerenkov radiator. An optically opaque enclosure is provided surrounding a detection chamber filled with the Cerenkov radiator, and photomultipliers are optically connected to the detect Cerenkov radiation generated by the Cerenkov radiator from incident high energy gamma rays or gamma rays induced by neutron capture on the Gd of incident neutrons from a fission source. The PMT signals are then used to determine time correlations indicative of neutron multiplicity events characteristic of a fission source.

  7. Optimization of a Light Collection System for use in the Neutron Lifetime Project

    Science.gov (United States)

    Taylor, C.; O'Shaughnessy, C.; Mumm, P.; Thompson, A.; Huffman, P.

    2007-10-01

    The Ultracold Neutron (UCN) Lifetime Project is an ongoing experiment with the objective of improving the average measurement of the neutron beta-decay lifetime. A more accurate measurement may increase our understanding of the electroweak interaction and improve astrophysical/cosmological theories on Big Bang nucleosynthesis. The current apparatus uses 0.89 nm cold neutrons to produce UCN through inelastic collisions with superfluid 4He in the superthermal process. The lifetime of the UCN is measured by detection of scintillation light from superfluid 4He created by electrons produced in neutron decay. Competing criteria of high detection efficiency outside of the apparatus and minimum heating of the experimental cell has led to the design of an acrylic light collection system. Initial designs were based on previous generations of the apparatus. ANSYS was used to optimize the cooling system for the light guide by checking simulated end conditions based on width of contact area, number of contact points, and location on the guide itself. SolidWorks and AutoCAD were used for design. The current system is in the production process.

  8. Impact of the layout of the ITER Radial Neutron Camera in-port system on the measurement of the neutron emissivity profile

    International Nuclear Information System (INIS)

    Highlights: ► MCNP ITER model ‘Alite-4′ has been updated with the new Port Plug structure (three vertical drawers). ► Two different layouts for the Radial Neutron Camera (RNC) in-vessel system have been considered. ► The impact of both layouts on the RNC diagnostic performance has been assessed. ► The analysis provides useful information for a proper integration of the RNC in the EPP1. -- Abstract: The Radial Neutron Camera (RNC), located in the ITER Equatorial Port Plug 1 (EPP1), is designed to provide the neutron emissivity profile through the measurement of the neutron flux along several collimated channels. The present design of the RNC is based on collimating structures: an ex-port system viewing the plasma core and an in-port system composed by two detector cassettes viewing the upper and lower plasma edges. A design of the EPP1 in which the diagnostics are installed in three completely independent vertical drawers is under study. In this frame, space optimization and integration issues suggest two possible solutions for the layout of the in-port RNC cassettes: the first one in which both cassettes are located in a side drawer; the second one in which the two cassettes lie in the central drawer, on opposite sides of the ex-port RNC cut-out. This paper describes the work performed to assess the impact of the two different in-port system layouts on the capability of the RNC to measure the neutron emissivity profile by means of MCNP and diagnostic performance calculations. The results of the analysis provide guidelines for the integration of the RNC into the EPP1 showing that the proximity of the in-port cassettes to the ex-port cut-out strongly increases the amount of uncollimated and scattered neutrons at the detector positions, thus reducing the diagnostic measurement capability

  9. Impact of the layout of the ITER Radial Neutron Camera in-port system on the measurement of the neutron emissivity profile

    Energy Technology Data Exchange (ETDEWEB)

    Marocco, D. [Associazione EURATOM-ENEA sulla Fusione ENEA C.R. Frascati, Via E. Fermi, 45, 00044 Frascati (Roma) (Italy); Moro, F., E-mail: fabio.moro@enea.it [Associazione EURATOM-ENEA sulla Fusione ENEA C.R. Frascati, Via E. Fermi, 45, 00044 Frascati (Roma) (Italy); Esposito, B.; Brolatti, G.; Villari, R. [Associazione EURATOM-ENEA sulla Fusione ENEA C.R. Frascati, Via E. Fermi, 45, 00044 Frascati (Roma) (Italy); Salasca, S.; Cantone, B. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2013-10-15

    Highlights: ► MCNP ITER model ‘Alite-4′ has been updated with the new Port Plug structure (three vertical drawers). ► Two different layouts for the Radial Neutron Camera (RNC) in-vessel system have been considered. ► The impact of both layouts on the RNC diagnostic performance has been assessed. ► The analysis provides useful information for a proper integration of the RNC in the EPP1. -- Abstract: The Radial Neutron Camera (RNC), located in the ITER Equatorial Port Plug 1 (EPP1), is designed to provide the neutron emissivity profile through the measurement of the neutron flux along several collimated channels. The present design of the RNC is based on collimating structures: an ex-port system viewing the plasma core and an in-port system composed by two detector cassettes viewing the upper and lower plasma edges. A design of the EPP1 in which the diagnostics are installed in three completely independent vertical drawers is under study. In this frame, space optimization and integration issues suggest two possible solutions for the layout of the in-port RNC cassettes: the first one in which both cassettes are located in a side drawer; the second one in which the two cassettes lie in the central drawer, on opposite sides of the ex-port RNC cut-out. This paper describes the work performed to assess the impact of the two different in-port system layouts on the capability of the RNC to measure the neutron emissivity profile by means of MCNP and diagnostic performance calculations. The results of the analysis provide guidelines for the integration of the RNC into the EPP1 showing that the proximity of the in-port cassettes to the ex-port cut-out strongly increases the amount of uncollimated and scattered neutrons at the detector positions, thus reducing the diagnostic measurement capability.

  10. Influence of Deformation on Light Particles as a Probe of Nuclear Dissipation for a Neutron-Deficient 178Pb System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Using a diffusion model we investigate deformation effects on the sensitivity of different light particles to nuclear dissipation for a rather neutron-deficient 178pb system. Calculations show that deformation significantly increases the sensitivity of neutron emission to dissipation strength, and that this effect becomes stronger with increasing deformation.

  11. Multidetector system for nanosecond tagged neutron technology based on hardware selection of events

    Science.gov (United States)

    Karetnikov, M. D.; Korotkov, S. A.; Khasaev, T. O.

    2016-09-01

    At the T( d, n)He4 reaction a neutron is accompanied by an associated alpha-particle emitted in the opposite direction. A time and a direction of the neutron escape can be determined by measuring a time and coordinates of the alpha particle at the position-sensitive alpha-detector. The nanosecond tagged neutron technology (NTNT) based on this principle has great potentialities for various applications, e.g., for remote detection of explosives. A spectrum of gamma-rays emitted at the interaction of tagged neutrons with nuclei of chemical elements allows identify a chemical composition of an irradiated object. For practical realization of NTNT, a time resolution of recording the alpha-gamma coincidences should be close to 1 ns. The total intensity of signals can exceed 1 × 106 1/s from all gamma-detectors and 7 × 106 1/s from the alpha-detector. The processing of such stream of data without losses and distortion of information is one of challenging problems of NTNT. Several models of analog DAQ system based on hardware selection of events were devised and their characteristics are examined. The comparison with the digital DAQ systems demonstrated that the analog DAQ provides better timing parameters, lower power consumption, and higher maximum rate of useful events.

  12. SBNCT plan: A 3-dimensional treatment planning system for boron neutron capture therapy

    International Nuclear Information System (INIS)

    The need for accurate and comprehensive 3-dimensional treatment planning for boron neutron capture therapy (BNCT) has been debated for the past several years. Although many argue against the need for elaborate and expensive treatment planning programs which mimic conventional radiotherapy planning systems, it is clear that in order to realize significant gains over conventional fractionated radiation therapy, patients must be treated to the edge of normal tissue tolerance. Just how close to this edge is dictated by the uncertainties in dosimetry. Hence the focus of BNCT planning is the determination of dose distribution throughout normal tissue volumes. Although precise geometric manipulation of the epithermal neutron beam is not achievable, the following variables play an important role in BNCT optimization: patient orientation, dose fractionation, number of fields, megawatt-minutes per fraction, use of surface bolus, and use of collimation. Other variables which are not as easily adjustable and would not, therefore, be part of treatment planning optimization, include external patient contour, internal patient heterogeneities, boron compound distributions, and RBE's. The boron neutron capture therapy planning system developed at SUNY Stony Brook (SBNCT-Plan) was designed as an interactive graphic tool to assist the radiation oncologist in generating the optimum plan for a neutron capture treatment

  13. Neutron chopper development at LANSCE

    International Nuclear Information System (INIS)

    Progress is reported on neutron chopper systems for the Los Alamos Neutron Scattering Center pulsed spallation neutron source. This includes the development of 600+ Hz active magnetic bearing neutron chopper and a high speed control system designed to operate with the Proton Storage Ring to phase the chopper to the neutron source. 5 refs., 3 figs

  14. Systems guide to MCNP (Monte Carlo Neutron and Photon Transport Code)

    International Nuclear Information System (INIS)

    The subject of this report is the implementation of the Los Alamos National Laboratory Monte Carlo Neutron and Photon Transport Code - Version 3 (MCNP) on the different types of computer systems, especially the IBM MVS system. The report supplements the documentation of the RSIC computer code package CCC-200/MCNP. Details of the procedure to follow in executing MCNP on the IBM computers, either in batch mode or interactive mode, are provided

  15. Accelerator system of neutron spallation source for nuclear energy technology development

    International Nuclear Information System (INIS)

    High intensity proton accelerators are at present and developed for applications in neutron spallation sources. The advantages of this source are better safety factor, easy in controlling and spent fuel free. A study of conceptual design of required accelerator system has been carried out. Considering the required proton beam and feasibility in the development stages, a stepped linac system is an adequate choice for now

  16. Input data requirements for special processors in the computation system containing the VENTURE neutronics code

    International Nuclear Information System (INIS)

    User input data requirements are presented for certain special processors in a nuclear reactor computation system. These processors generally read data in formatted form and generate binary interface data files. Some data processing is done to convert from the user oriented form to the interface file forms. The VENTURE diffusion theory neutronics code and other computation modules in this system use the interface data files which are generated

  17. The merging of white dwarf and neutron star systems: gravitational radiation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Berro, Enrique [Departament de Fisica Aplicada, Escola Politecnica Superior de Castelldefels, Universitat Politecnica de Catalunya, Avda. del Canal OlImpic s/n, 08860 Castelldefels (Spain); Pedemonte, Alba G [Departament de Fisica Aplicada, Escola Politecnica Superior de Castelldefels, Universitat Politecnica de Catalunya, Avda. del Canal OlImpic s/n, 08860 Castelldefels (Spain); GarcIa-Senz, Domingo [Departament de Fisica i Enginyeria Nuclear, Facultat de Informatica de Barcelona, Universitat Politecnica de Catalunya, c/ Jordi Girona Salgado, s/n, 08034, Barcelona (Spain); Loren-Aguilar, Pablo [Institut de Ciencies de l' Espai, CSIC, Facultat de Ciencies, Campus UAB, 08193 Bellaterra (Spain); Isern, Jordi [Institut de Ciencies de l' Espai, CSIC, Facultat de Ciencies, Campus UAB, 08193 Bellaterra (Spain); Lobo, Jose A [Institut de Ciencies de l' Espai, CSIC, Facultat de Ciencies, Campus UAB, 08193 Bellaterra (Spain)

    2007-05-15

    We have computed the gravitational wave emission arising from the coalescence of binary systems composed of a white dwarf and a neutron star. In order to do so, we have followed the evolution of such systems using a Smoothed Particle Hydrodynamics code. Here we present some of the results obtained so far, paying special attention to the detectability of the emitted gravitational waves. Within this context, we show which could be the impact of individual merging episodes for LISA.

  18. A digital data acquisition system for a time of flight neutron diffuse scattering instrument

    International Nuclear Information System (INIS)

    Full text. We describe the design of a digital data acquisition system built for acquiring and storing the information produced by a neutron diffuse scattering apparatus. This instrument is based on the analysis of pulsed subthermal neutron which are scattered by a solid or liquid sample, measured as function of the scattered neutron wavelength and momentum direction. The time of flight neutron intensities on 14 different angular detector positions and two fission chambers must be analyzed simultaneously for each neutron burst. A PC controlled data acquisition board system was built based on two parallel multiscannning units, each with its own add-one counting unit, and a common base time generator. The unit plugs onto the ISA bus through an interface card. Two separate counting units were designed, to avoid possible access competition between low counting rate counters at off-axis positions and the higher rate frontal 0 deg and beam monitoring counters. the first unit contains logic for 14 independent and simultaneous multi scaling inputs, with 128 time channels and dwell time per channel of 5, 10 or 20 microseconds. Sweep trigger is synchronized with an electric signal from a coil sensing the rotor. The second unit contains logic for four additional multi scalers using the same external synchronizing signal, similar in all others details to the previously described multi scalers. Basic control routines for the acquisitions were written in C and a program for spectrum display and user interface was written in C++ for a Windows 3.1 OS. A block diagram of the system is presented

  19. Integrated system for production of neutronics and photonics calculational constants. Neutron-induced interactions: index of experimental data

    Energy Technology Data Exchange (ETDEWEB)

    MacGregor, M.H.; Cullen, D.E.; Howerton, R.J.; Perkins, S.T.

    1976-07-04

    Indexes to the neutron-induced interaction data in the Experimental Cross Section Information Library (ECSIL) as of July 4, 1976 are tabulated. The tabulation has two arrangements: isotope (ZA) order and reaction-number order.

  20. Development and demonstration of in-situ SEOP 3He spin filter system for neutron spin analyzer on the SHARAKU polarized neutron reflectometer at J-PARC

    International Nuclear Information System (INIS)

    A new neutron reflectometer, SHARAKU, with a vertical sample-plane geometry was installed at beam line 17 at J-PARC Materials and Life Science Facility. Although a polarizing supermirror was previously installed as a neutron spin analyzer on SHARAKU, a 3He spin filter is advantageous because it can cover a large solid angle. An in-situ SEOP 3He spin filter system using a new compact laser unit has been developed for the analyzer. In this paper, we report a successful off-specular measurement with the new compact in-situ SEOP analyzer at SHARAKU.

  1. Validation of neutronic methods applied to the analysis of fast subcritical systems. The MUSE-2 experiments

    International Nuclear Information System (INIS)

    In the framework of the French SPIN program devoted to the separation and the transmutation of radioactive wastes, the CEA has launched the ISAAC program to investigate the potential of accelerator-driven systems and to provide an experimental validation of the physics characteristics of these systems. The neutronics of the subcritical core needs experimental validation. This can be done by decoupling the problem of the neutron source from the problem of the subcritical medium. Experiments with a well known external source placed in a subcritical medium have been performed in the MASURCA facility. The results confirm the high accuracy achievable with such experiments and the good quality of the ERANOS code system predictions. (author)

  2. Validation of neutronic methods applied to the analysis of fast subcritical systems. The MUSE-2 experiments

    Energy Technology Data Exchange (ETDEWEB)

    Soule, R.; Salvatores, M.; Jacqmin, R.; Martini, M.; Lebrat, J.F.; Bertrand, P. [CEA Centre d`Etudes de Cadarache, Service de Physique des Reacteurs et du Cycle, 13 - Saint-Paul-lez-Durance (France); Broccoli, U.; Peluso, V.

    1997-12-31

    In the framework of the French SPIN program devoted to the separation and the transmutation of radioactive wastes, the CEA has launched the ISAAC program to investigate the potential of accelerator-driven systems and to provide an experimental validation of the physics characteristics of these systems. The neutronics of the subcritical core needs experimental validation. This can be done by decoupling the problem of the neutron source from the problem of the subcritical medium. Experiments with a well known external source placed in a subcritical medium have been performed in the MASURCA facility. The results confirm the high accuracy achievable with such experiments and the good quality of the ERANOS code system predictions. (author)

  3. Gamma compensated pulsed ionization chamber wide range neutron/reactor power measurement system

    International Nuclear Information System (INIS)

    An improved method and system of pulsed mode operation of ionization chambers is described in which a single sensor system with gamma compensation is provided by sampling, squaring, automatic gate selector, and differential amplifier circuit means, employed in relation to chambers sensitized to neutron plus gamma and gamma only to subtract out the gamma component, wherein squaring functions circuits, a supplemental high performance pulse rate system, and operational and display mode selection and sampling gate circuits are utilized to provide automatic wide range linear measurement capability for neutron flux and reactor power. Neon is employed as an additive in the ionization chambers to provide independence of ionized gas kinetics temperature effects, and the pulsed mode of operation provide independence of high temperature insulator leakage effects. (auth)

  4. Development of a neutron measurement system in unified non-destructive assay for the PRIDE facility

    Science.gov (United States)

    Seo, Hee; Park, Se-Hwan; Won, Byung-Hee; Ahn, Seong-Kyu; Shin, Hee-Sung; Na, Sang-Ho; Song, Dae-Yong; Kim, Ho-Dong; Lee, Seung Kyu

    2013-12-01

    The Korea Atomic Energy Research Institute (KAERI) has made an effort to develop pyroprocessing technology to resolve an on-going problem in Korea, i.e., the management of spent nuclear fuels. To this end, a test-bed facility for pyroprocessing, called PRIDE (PyRoprocessing Integrated inactive DEmonstration facility), is being constructed at KAERI. The main objective of PRIDE is to evaluate the performance of the unit processes, remote operation, maintenance, and proliferation resistance. In addition, integrating all unit processes into a one-step process is also one of the main goals. PRIDE can also provide a good opportunity to test safeguards instrumentations for a pyroprocessing facility such as nuclear material accounting devices, surveillance systems, radiation monitoring systems, and process monitoring systems. In the present study, a non-destructive assay (NDA) system for the testing of nuclear material accountancy of PRIDE was designed by integrating three different NDA techniques, i.e., neutron, gamma-ray, and mass measurements. The developed neutron detection module consists of 56 3He tubes and 16 AMPTEK A111 signal processing circuits. The amplifiers were matched in terms of the gain and showed good uniformity after a gain-matching procedure (%RSD=0.37%). The axial and the radial efficiency distributions within the cavity were then measured using a 252Cf neutron source and were compared with the MCNPX calculation results. The measured efficiency distributions showed excellent agreement with the calculations, which confirmed the accuracy of the MCNPX model of the system.

  5. The hypertext information system on pulsed neutron sources and scientific investigations based on these sources

    International Nuclear Information System (INIS)

    The work on the creation of the hypertext information system has been performed on the basis of the web-server of the Frank Laboratory of Neutron Physics, JINR. The initial project proposed the creation of HTML information resources and did not consider the usage of any database for the information management. During the project implementation it became obvious that the system should have well defined structured informational model and it might be helpful to imply the relational database as a part of the system. The ORACLE server at the Laboratory of Computing Techniques and Automation (LCTA) of the JINR has been used for this task. Now we have a set of ORACLE tables designed using CASE tools for the informational model of the system, structured information about neutron sources, neutron instruments, printed publications and URL addresses. We have also the web interface to these tables using free ware gateway ORALINK installed on our Pentium PC with Windows NT and some tools to administer database and view pictures stored in the tables. We took into account NeXuS specifications while tried to design the informational model of the system, and we continue to work on its creation

  6. Linearity improvement on wide-range log signal of neutron measurement system for HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ki [KAERI, Taejon (Korea, Republic of); Tuetken, Jeffrey S. [GAMMA-METRICS, CA (United States)

    1998-07-01

    This paper discusses engineering activities for improving the linearity characteristics of the Log Power signal from the neutron measurement system for HANARO. The neutron measurement system for HANARO, uses a fission chamber based detector which covers 10.3 decade range from 10{sup -8} percent full power (FP) up to 200 percent FP. The Log Power signal is designed to control the reactor at low power levels where most of the reactor physics tests are carried out . Therefore, the linearity characteristics of the Log Power signal is the major factor for accurate reactor power control. During the commissioning of the neutron measurement system, it was found that the linearity characteristics of the Log Power signal, especially near 10{sup -}2 percent FP, were not accurate enough for controlling the reactor during physics testing. Analysis of the system behavior with the manufacturer, GAMMA-METRICS, determined that the system was not operating per the design characteristics established from previous installations. The linearity data, which were taken as the reactor was increased in power, were sent to the engineering group and a follow-up measures based on the analysis were then fed back to the field. Through step by step trouble-shooting activities, which included minor circuit changes and alignment procedure changes, the linearity characteristics have been successfully improved and now exceed minimum performance requirements. This paper discusses the trouble-shooting techniques applied, the changes in the linearity characteristics, special circumstances in the HANARO application, and the final resolution. (author)

  7. Linearity improvement on wide-range log signal of neutron measurement system for HANARO

    International Nuclear Information System (INIS)

    This paper discusses engineering activities for improving the linearity characteristics of the Log Power signal from the neutron measurement system for HANARO. This neutron measurement system uses a fission chamber based detector which covers 10.3 decade-wide range from 10-8% full power(FP) up to 200%FP, The Log Power signal is designed to control the reactor at low power levels where most of the reactor physics tests are carried out. Therefore, the linearity characteristics of the Log Power signal is the major factor for accurate reactor power control. During the commissioning of the neutron measurement system, it was found that the linearity characteristics of the Log Power signal, especially near 10-2%FP, were not accurate enough for controlling the reactor during physics testing. Analysis of the system linearity data directly measured with reactor operating determined that the system was not operating per the design characteristics established from previous installations. The linearity data, which were taken as the reactor was increased in power, were sent to manufacturer's engineering group and a follow-up measures based on the analysis were then fed back to the field. Through step by step trouble-shooting activities, which included minor circuit modifications and alignment procedure changes, the linearity characteristics have been successfully improved and now exceed minimum performance requirements. This paper discusses the trouble-shooting techniques applied, the changes in the linearity characteristics, special circumstances in the HANARO application and the final resolution. (author)

  8. Irradiation Effects for the Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System

    Energy Technology Data Exchange (ETDEWEB)

    Slater, C.O.

    2001-02-02

    At the request of Safety and Ecology Corporation of Tennessee, radiation effects of the proposed Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System have been examined. First, fissile cargo were examined to determine if a significant neutron signal would be observable during interrogation. Results indicated that ample multiplication would be seen for near critical bare targets. The water-reflected sphere showed relatively little multiplication. By implication, a fissile target shielded by hydrogenous cargo might not be detectable by neutron interrogation, particularly if reliance is placed on the neutron signal. The cargo may be detectable if use can be made of the ample increase in the photon signal. Second, dose rates were calculated at various locations within and just outside the facility building. These results showed that some dose rates may be higher than the target dose rate of 0.05 mrem/h. However, with limited exposure time, the total dose may be well below the allowed total dose. Lastly, estimates were made of the activation of structures and typical cargo. Most cargo will not be exposed long enough to be activated to levels of concern. On the other hand, portions of the structure may experience buildup of some radionuclides to levels of concern.

  9. Computed neutron response of spherical moderator-detector systems for radiation protection monitoring

    International Nuclear Information System (INIS)

    Neutrons of energies below 500 keV are important from the point of view of radiation protection of personnel working around reactors. However, as no neutron sources are available at lower energies, no measured values of neutron energy response are available between thermal and 0.5 MeV (but for Sb-Be source at 24 keV). The response functions in this range are, therefore, arrived at theoretically. After giving a comprehensive review of the work done in the field of response of moderated neutron detectors, a Monte Carlo method developed for this purpose is described and used to calculate energy response functions of the two spherical moderator-detector systems, namely, one using a central BF3 counter and the other using 6LiI(Eu) scintillator of 0.490 dia crystal. The polythene sphere diameter ranged from 2'' to 12''. The results obtained follow the trend predicted by other calculations and experiments, but are a definite improvement over them, because the most recent data on cross sections and angular distribution are used and the opacity of the detector i.e. the presence and size of the detector within the moderator is taken into account in the present calculations. The reasons for the discrepancies in the present results and those obtained earlier by other methods are discussed. The response of the Leake counter arrived at by the present method agrees very well with experimental calibration. (M.G.B.)

  10. Neutron cross-sections for advanced nuclear systems. The nTOF project at CERN

    International Nuclear Information System (INIS)

    In 2012, nuclear energy continued to play an important role in global electricity production. Despite a small reduction of the total generating nuclear power capacity after the accident at the Fukushima Daiichi nuclear power plant, a significant growth, between 35% and 100% by 2030, is foreseen in the use of nuclear energy worldwide. The knowledge of a wide variety of nuclear processes is a fundamental prerequisite in nuclear technology, as well as in other field of fundamental and applied Nuclear Physics. In particular, neutron-induced reactions play a key role in the operation of present nuclear reactors as well as in the design of future ones aiming at minimizing nuclear waste, such as Generation-IV reactors, ADS or reactors based on Th/U fuel cycle. The cross sections of a large number of neutron-induced reactions are requested with high accuracy to improve safety and efficiency of current reactors, and for the design of future generation systems. Since 2001 nTOF, an innovative neutron Time-Of-Flight facility, has been operating at CERN with the aim of addressing the needs of nuclear data for basic and applied nuclear Physics. An extensive program on both neutron induced fission and capture reactions has been carried out so far. Thanks to the well suited features of the nTOF neutron beam, such as the high instantaneous neutron flux, the high resolution and the wide energy range covered, from thermal to a few GeV, coupled with state-of-the-art detectors and data acquisition system, it has been possible to collect high accuracy and high resolution neutron cross-section data on a variety of isotopes, many of which radioactive. In particular, important results for nuclear technologies have been obtained on isotopes of U, Pu and minor actinides with long half life. Recently the construction of a new, high-flux measuring station has started. A 25 times higher fluence relative to the existing experimental area will allow to measure isotopes with short half life, as

  11. A neutron booster for spallation sources—application to accelerator driven systems and isotope production

    Science.gov (United States)

    Galy, J.; Magill, J.; Van Dam, H.; Valko, J.

    2002-06-01

    One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the μm-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology—for example in the design neutron amplifiers for medical applications and "fast" islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module could be developed for spallation targets foreseen in the MYRRHA (L. Van Den Durpel, H. Aı̈t Abderrahim, P. D'hondt, G. Minsart, J.L. Bellefontaine, S. Bodart, B. Ponsard, F. Vermeersch, W. Wacquier. A prototype accelerator driven system in Belgium: the Myrrha project, Technical Committee Meeting on Feasibility and Motivation for Hybrid concepts for Nuclear Energy generation and Transmutation, Madrid, Spain, September 17-19, 1997 [1]). or MEGAPIE (M. Salvatores, G.S. Bauer, G. Heusener. The MEGAPIE initiative: executive outline and status as per November 1999, MPO-1-GB-6/0_GB, 1999 [2]) projects. With a neutron multiplication factor of the booster unit in the range 10-20 (i.e. with a keff of 0.9-0.95), considerably less powerful accelerators would be required to obtain the desired neutron flux. Instead of the powerful accelerators with proton energies of 1 GeV and currents of 10 mA foreseen for accelerator driven systems, similar neutron fluxes can be obtained

  12. Stability Measurements for Alignment of the NIF Neutron Imaging System Pinhole Array

    International Nuclear Information System (INIS)

    The alignment system for the National Ignition Facility's neutron imaging system has been commissioned and measurements of the relative stability of the 90-315 DIM, the front and the back of the neutron imaging pinhole array and an exploding pusher target have been made using the 90-135 and the 90-258 opposite port alignment systems. Additionally, a laser beam shot from the neutron-imaging Annex and reflected from a mirror at the back of the pinhole array was used to monitor the pointing of the pinhole. Over a twelve hour period, the relative stability of these parts was found to be within ∼ ±18 (micro)m rms even when using manual methods for tracking the position of the objects. For highly visible features, use of basic particle tracking techniques found that the front of the pinhole array was stable relative to the 90-135 opposite port alignment camera to within ±3.4 (micro)m rms. Reregistration, however, of the opposite port alignment systems themselves using the target alignment sensor was found to change the expected position of target chamber center by up to 194 (micro)m.

  13. Design progress of cryogenic hydrogen system for China Spallation Neutron Source

    Science.gov (United States)

    Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K.

    2014-01-01

    China Spallation Neutron Source (CSNS) is a large proton accelerator research facility with 100 kW beam power. Construction started in October 2011 and is expected to last 6.5 years. The cryogenic hydrogen circulation is cooled by a helium refrigerator with cooling capacity of 2200 W at 20 K and provides supercritical hydrogen to neutron moderating system. Important progresses of CSNS cryogenic system were concluded as follows. Firstly, process design of cryogenic system has been completed including helium refrigerator, hydrogen loop, gas distribution, and safety interlock. Secondly, an accumulator prototype was designed to mitigate pressure fluctuation caused by dynamic heat load from neutron moderation. Performance test of the accumulator has been carried out at room and liquid nitrogen temperature. Results show the accumulator with welding bellows regulates hydrogen pressure well. Parameters of key equipment have been identified. The contract for the helium refrigerator has been signed. Mechanical design of the hydrogen cold box has been completed, and the hydrogen pump, ortho-para hydrogen convertor, helium-hydrogen heat exchanger, hydrogen heater, and cryogenic valves are in procurement. Finally, Hydrogen safety interlock has been finished as well, including the logic of gas distribution, vacuum, hydrogen leakage and ventilation. Generally, design and construction of CSNS cryogenic system is conducted as expected.

  14. Neutron tomography

    International Nuclear Information System (INIS)

    In this paper a survey is given of recent developments in selected areas of neutron tomography, within the context of several applications Argonne is involved in, including high penetration of reactor-fuel bundles in thick containers (involving TREAT and NRAD facilities), dual-energy hydrogen imaging (performed at IPNS), dynamic coarse-resolution emission tomography of rector fuel under test (a proposed modification to the TREAT hodoscope), and an associated-particle system that uses neutron flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays

  15. Performance tests on PNL's transportable neutron/gamma waste waste assay system

    International Nuclear Information System (INIS)

    Battelle Pacific Northwest Laboratory, in conjunction with Canberra Industries, has implemented a 55-gallon drum waste assay system. The single system unit consists of a combined segmented gamma assay system and a neutron assay system. The unit is designed to function either in the laboratory or in a mobile trailer. The system is on wheels and can be moved through standard double doors. The gamma system uses an HPGe detector with a Se-75 source for transmission corrections. The neutron detector uses 40 He-3 detectors connected to a JSR-12 neutron coincidence counter. The system's software is unique and is interactive with the user; it features a menu driven operator screen from which all functions regarding operations and calibrations can be selected. Single or combined assays with various setups, including containers smaller than 55 gallons, may be performed. The software and analysis is designed for unknown waste contents, but allows input of waste stream information prior to assay. The system was originally designed for safeguards' MC ampersand A requirements and has enough sensitivity to determine whether a drum is TRU or LLW in one assay pass. Typical counting times are approximately 1800 seconds for a dual pass. Preliminary testing of the system with the available Pu standards has shown the system will perform to the required levels stated in the Data Quality Objectives of the WIPP Performance Demonstration program. An overall study of the system is underway to determine the lower limit of detection (LLD) for different isotopes, to best utilize the combined assay results, and to apply the appropriate data corrections for more complete answers, such as corrections for the end effects. Results from these developments will be presented at the conference

  16. An automated neutron dosimetry system based on the chemical etch of CR-39

    International Nuclear Information System (INIS)

    The dosimetric characteristics of two types of personal neutron dosemeter have recently been extensively assessed. The effects of exposure to various extreme environments have also been studied. Both types of dosemeter utilise chemically etched elements which are read in an automated reader, the Autoscan 60, which uses an edge illumination system to increase the pit image size. One type of dosemeter contains three elements in a pyramid structure. The other uses one or two elements in a planar structure. The results indicate that both types of dosemeter can be used to assess accurately the personal dose from neutrons in a range of harsh environments. Formal approval for the operational use of the system has been received. (author)

  17. Cf-252 based neutron radiography using real-time image processing system

    International Nuclear Information System (INIS)

    For compact Cf-252 based neutron radiography, a real-time image processing system by particle counting technique has been developed. The electronic imaging system consists of a supersensitive imaging camera, a real-time corrector, a real-time binary converter, a real-time calculator for centroid, a display monitor and a computer. Three types of accumulated NR image; ordinary, binary and centroid images, can be observed during a measurement. Accumulated NR images were taken by the centroid mode, the binary mode and ordinary mode using of Cf-252 neutron source and those images were compared. The centroid mode presented the sharpest image and its statistical characteristics followed the Poisson distribution, while the ordinary mode showed the smoothest image as the averaging effect by particle bright spots with distributed brightness was most dominant. (author)

  18. Neutronic and burnup studies of accelerator-driven systems dedicated to nuclear waste transmutation

    OpenAIRE

    Tucek, Kamil

    2004-01-01

    Partitioning and transmutation of plutonium, americium, and curium is inevitable if the radiotoxic inventory of spent nuclear fuel is to be reduced by more than a factor of 100. But, admixing minor actinides into the fuel severely degrades system safety parameters, particularly coolant void reactivity, Doppler effect, and (effective) delayed neutron fractions. The incineration process is therefore envisioned to be carried out in dedicated, accelerator-driven sub-critical reactors (ADS). Howev...

  19. Software development of the mechanical vibration monitoring system of the CNA I reactor internals by neutron noise technique

    International Nuclear Information System (INIS)

    The neutron noise analysis technique is an important predictive maintenance tool for early detection of failures such as sensor malfunctions and incipient mechanical problems located in the reactor internals. This technique was applied successfully in Argentina since 1987. The FER-GAEN group dependent of the CNEA developed the measuring system to detect anomalies as early as possible. The magnitude of interest in this analysis is the fluctuating component of the neutron flux known as 'neutron noise'. In order to improve and facilitate the analysis, a new software code was developed for the data acquisition of the neutron noise signals and neutron spectra estimation in the frequency domain. The RMS values related with the internals vibrations are calculated from these spectra and are chronologically displayed, in order to detect any anomalous vibration or incipient detector malfunction as early as possible. (author)

  20. Use of a spherical albedo system for correcting the readings of albedo dosimeters in JINR phasotron neutron radiation fields

    Science.gov (United States)

    Mokrov, Yu. V.; Morozova, S. V.

    2014-03-01

    Results of calibrating a spherical albedo system in the radiation fields of a Pu-Be radionuclide neutron source are presented. It is shown that it can be used for correcting the readings of the DVGN-01 albedo dosimeter. The results of measurements with the system in JINR phasotron neutron fields for the purpose of correcting the DVGN-01 readings in these fields are given. The values of the correction factors for DVGN-01 albedo dosimeters when used in personnel neutron dosimetry (PD) on the JINR phasotron are determined.

  1. Neutronics Analysis of the ITER In-Vessel Viewing System

    CERN Document Server

    Turner, Andrew; Puiu, Adrian

    2013-01-01

    The In-Vessel Viewing System (IVVS) in ITER consists of six identical units which are deployed between pulses or during shutdown, to perform visual examination and metrology of plasma facing components. The system is housed in dedicated ports at B1 level, with deployment at the level between the divertor cassettes and the lowermost outboard blanket modules. Boron carbide shielding blocks are envisaged to protect the sensitive components of the IVVS from damage during operations, and personnel from radiation fields. In order to progress the design of the IVVS beyond the pre-conceptual stage, analyses were conducted using MCNP to determine the acceptability of a series of different shielding configurations.

  2. Neutron CT with a multi-detector system leading to drastical reduction of the measuring time

    International Nuclear Information System (INIS)

    By means of numerical simulation methods and their verification with measurements it could be shown that such a detector system can be realized for a line beam and 1-2 detectors per cm. With the maximum available beam width of the fast neutron field at the FRM approximately 20 detectors can be used leading to a reduction of the measuring time to 0,5 - 1 hour. A multi detector system for a line beam of thermal neutrons was constructed, tested and used for CT-measurements. This detector system for the measurement of thinner layers with better spatial resolution could be realized. The electronic discrimination between neutrons and gamma rays has been improved. This discrimination was used in all CT-measurements to get transmission values of both kinds of radiation and to reconstruct to complementary CT-images. The use of a polyenergetic radiation causes spectral shifts in the transmission spectrum leading to artifacts in the reconstructed CT-image. The transmission values must be spectral corrected before image reconstruction, because the image artifacts complicate the image evaluation or make it impossible. A new energy selective procedure for the online spectral correction was developed. This method is based on the concept to measure additionally to the integral transmission value his pulse height spectrum and to do the correction depending on the changes in this pulse height spectrum. (orig./HP)

  3. Training courses on the use of neutron detection systems carried out on the ISIS research reactor

    International Nuclear Information System (INIS)

    Training courses on the use of the neutron detection systems for the control of the nuclear reactors are carried out by the National Institute for Nuclear Science using the ISIS research reactor. The study and the comprehension of the operation of these systems are facilitated by the use a research reactor in order to observe the electronic signals in real conditions. Thus, ISIS reactor offers a wide range of neutron fluxes and the level of power can be easily set to any value from zero to nominal power (700 kW). Different kinds of detectors (counters, ionization chambers), which operate in the different modes of detection (pulse, current and Campbelling) can be placed in the periphery of the core for the courses. The electronic signal can be analyzed at each step of the detection process. One goal of the courses is to understand the role of each component of the detection system: detector, cable and each electronic module. A comparison with the nuclear instrumentation used by the instrumentation and control of ISIS reactor is also made. This comparison is very useful to understand the role of the neutron instrumentation in terms of safety, availability, reliability and maintainability. (authors)

  4. Some existing Experimental Facilities for Fast Neutron Systems at KIT

    International Nuclear Information System (INIS)

    An overview is given of: • Liquid Metal Loops at the Karlsruhe Liquid Metal Laboratory (KALLA) of KIT; • THESYS: Technologies for HEavy metal SYStems; • Thermal Hydraulic experiments in THESYS; • THEADES: THErmalhydraulics and Ads DESign; • Thermal Hydraulic experiments in THEADES; • CORRIDA: CORRosion In Dynamic lead Alloys; • Experimental stagnant facilities at KALLA; • INR Liquid metal research

  5. The Measurement of Reactivity In Multiregion Subcritical Systems by the Pulsed Neutron Technique

    International Nuclear Information System (INIS)

    The prompt decay of a thermalized burst of neutrons in a multiregion subcritical system is examined using a two-group diffusion theory. It is shown that a relationship can be established between the prompt decay constant of the fundamental mode and the effective multiplication factor of the system in terms of two parameters, defined, for the purposes of this paper, as the reactor response coefficient and the prompt decay correction and which depend to a large extent on the spatial flux patterns within the system. For the uniform bare system, the response coefficient can be identified with the mean neutron lifetime in the system; for a multiregion system it represents a compound of the lifetimes in each region weighted by perturbation type integrals. The second parameter, the decay correction, can have no physical meaning in that it arises from an attempt to relate the two scales of reactivity involved; that is the scale using the prompt decay constant and the scale derived using the effective multiplication factor. The properties of these parameters are examined here with reference to an enriched uranium graphitemoderated reactor consisting of uniform core and reflector and it is shown that the two parameters are not uniquely defined by the reactivity of the system but depend on the method chosen to make the system subcritical. Two sets of measurements are treated by the theory. In one, the Windscale Advanced Gas-Cooled Reactor was shut down by a uniform poison. In the other the reactivity of a core in the zero-energy reactor HERO was varied by altering the loaded radius. The neutron pulse measurements are all shown to be in good agreement with more conventional methods of reactivity determination. Some discussion of the experimental techniques and the difficulties encountered in the graphite-moderated systems is presented. (author)

  6. Development of a high spatial resolution neutron imaging system and performance evaluation

    Science.gov (United States)

    Cao, Lei

    The combination of a scintillation screen and a charged coupled device (CCD) camera is a digitized neutron imaging technology that has been widely employed for research and industry application. The maximum of spatial resolution of scintillation screens is in the range of 100 mum and creates a bottleneck for the further improvement of the overall system resolution. In this investigation, a neutron sensitive micro-channel plate (MCP) detector with pore pitch of 11.4 mum is combined with a cooled CCD camera with a pixel size of 6.8 mum to provide a high spatial resolution neutron imaging system. The optical path includes a high reflection front surface mirror for keeping the camera out of neutron beam and a macro lens for achieving the maximum magnification that could be achieved. All components are assembled into an aluminum light tight box with heavy radiation shielding to protect the camera as well as to provide a dark working condition. Particularly, a remote controlled stepper motor is also integrated into the system to provide on-line focusing ability. The best focus is guaranteed through use of an algorithm instead of perceptual observation. An evaluation routine not previously utilized in the field of neutron radiography is developed in this study. Routines like this were never previously required due to the lower resolution of other systems. Use of the augulation technique to obtain presampled MTF addresses the problem of aliasing associated with digital sampling. The determined MTF agrees well with the visual inspection of imaging a testing target. Other detector/camera combinations may be integrated into the system and their performances are also compared. The best resolution achieved by the system at the TRIGA Mark II reactor at the University of Texas at Austin is 16.2 lp/mm, which is equivalent to a minimum resolvable spacing of 30 mum. The noise performance of the device is evaluated in terms of the noise power spectrum (NPS) and the detective quantum

  7. Neutron-Induced Failures in Semiconductor Devices

    Energy Technology Data Exchange (ETDEWEB)

    Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-06

    This slide presentation explores single event effect, environmental neutron flux, system response, the Los Alamos Neutron Science Center (LANSCE) neutron testing facility, examples of SEE measurements, and recent interest in thermal neutrons.

  8. Gamma-ray and neutron area monitoring system of linear IFMIF prototype accelerator building

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroki, E-mail: takahashi.hiroki@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori (Japan); Kojima, Toshiyuki; Narita, Takahiro; Tsutsumi, Kazuyoshi; Maebara, Sunao [Japan Atomic Energy Agency (JAEA), Rokkasho, Aomori (Japan); Sakaki, Hironao [JAEA, Kizugawa, Kyoto (Japan); Nishiyama, Koichi [IFMIF/EVEDA Project Team, Rokkasho, Aomori (Japan)

    2013-10-15

    Highlights: • Area monitoring system and control system are needed for LIPAc radiation management. • To secure the radiation safety, these systems are linked with two kinds of data path. • Hardwired data paths are adopted to realize the fast transfer of interlock signals. • Dual LAN and shared memory are adopted to the reliable transfer of monitoring data. • Data transfers without unnecessary load are designed and configured for these systems. -- Abstract: The linear IFMIF prototype accelerator (LIPAc) produces deuteron beam with 1 MW power. Since huge number of neutrons occur from such a high power beam, therefore, it is important for the radiation management to design a high reliability area monitoring system for gamma-rays and neutrons. To obtain the valuable operation data of the high-power deuteron beam at LIPAc, it is important to link and record the beam operation data and the area monitoring data. We realize the reliable data transfer to provide the area monitoring data to the accelerator control system which needs a high reliability using the shared-memory data link method. This paper describes the area monitoring system in the LIPAc building and the data-link between this system and the LIPAc control system.

  9. Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

    OpenAIRE

    Bromberger, B.; Bar, D.; Brandis, M.; Dangendorf, V.; Goldberg, M B; Kaufmann, F.; Mor, I.; Nolte, R.; SCHMIEDEL M.; Tittelmeier, K.; Vartsky, D.; H. Wershofen

    2012-01-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and ga...

  10. An automated microcomputer-controlled system for neutron activation and gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    An automated instrumental neutron activation analysis (INAA) system has been constructed at the SLOWPOKE-2 reactor at the Royal Military College of Canada (RMC). Its pneumatic transfer system is controlled by an Apple IIe computer, linked in turn to an MS-DOS-compatible microcomputer which controls data acquisition. Custom software has been created for these computers and for off-line spectral analysis using programs that incorporate either peak boundary or Gaussian peak fitting methods of analysis. This system provides the gamut of INAA techniques for the analyst. The design and performance of the hardware and software are discussed. (orig.)

  11. An automated microcomputer-controlled system for neutron activation and gamma-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Edward, J.B.; Bennett, L.G.I. (Royal Military Coll. of Canada, Kingston, ON (Canada). SLOWPOKE-2 Facility Royal Military Coll. of Canada, Kingston, ON (Canada). Dept. of Chemistry and Chemical Engineering); Beeley, P.A. (Royal Military Coll. of Canada, Kingston, ON (Canada). SLOWPOKE-2 Facility Queen' s Univ., Kingston, Ontario (Canada). Dept. of Chemistry); Anderson, A.; Burbidge, G.A. (Royal Military Coll. of Canada, Kingston, ON (Canada). SLOWPOKE-2 Facility Nordion International, Inc., Kanata, ON (Canada))

    1990-12-20

    An automated instrumental neutron activation analysis (INAA) system has been constructed at the SLOWPOKE-2 reactor at the Royal Military College of Canada (RMC). Its pneumatic transfer system is controlled by an Apple IIe computer, linked in turn to an MS-DOS-compatible microcomputer which controls data acquisition. Custom software has been created for these computers and for off-line spectral analysis using programs that incorporate either peak boundary or Gaussian peak fitting methods of analysis. This system provides the gamut of INAA techniques for the analyst. The design and performance of the hardware and software are discussed. (orig.).

  12. A novel fast-neutron tomography system based on a plastic scintillator array and a compact D-D neutron generator.

    Science.gov (United States)

    Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

    2016-01-01

    Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D-T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D-D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a discussion

  13. Pneumatic sample-transfer system for use with the Lawrence Livermore National Laboratory rotating target neutron source (RTNS-I)

    International Nuclear Information System (INIS)

    A pneumatic sample-transfer system is needed to be able to rapidly retrieve samples irradiated with 14-MeV neutrons at the Rotating Target Neutron Source (RTNS-I). The rabbit system, already in place for many years, has been refurbished with modern system components controlled by an LSI-11 minicomputer. Samples can now be counted three seconds after an irradiation. There are many uses for this expanded 14-MeV neutron activation capability. Several fission products difficult to isolate from mixed fission fragments can be produced instead through (n,p) or (n,α) reactions with stable isotopes. Mass-separated samples of Nd, Mo, and Se, for example, can be irradiated to produce Pr, Nb, and As radionuclides sufficient for decay scheme studies. The system may also be used for multielement fast-neutron activation analysis because the neutron flux is greater than 2 x 1011 n/cm2-sec. Single element analyses of Si and O are also possible. Finally, measurements of fast-neutron cross sections producing short-lived activation products can be performed with this system. A description of the rabbit system and instructions for its use are presented in this report

  14. A neutron booster for spallation sources--application to accelerator driven systems and isotope production

    CERN Document Server

    Galy, J; Van Dam, H; Valko, J

    2002-01-01

    One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the mu m-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology--for example in the design neutron amplifiers for medical applications and 'fast' islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module cou...

  15. FURNACE 2. Toroidal geometry neutronic program system method. Description and users manual

    Energy Technology Data Exchange (ETDEWEB)

    Verschuur, K.A.

    1995-10-01

    FURNACE2 is a 3-dimensional neutron/photon-transport program system for toroidal geometries. It uses ray-tracing and double-differential reflection-and transmission-coefficients and flux-kernels to calculate the angular-flux spectra inside the torus of a fusion-reactor. FURNACE2 is an extended version of FURNACE, developed for application to the neutron-diagnostics at JET, which was supported financially by JET. It is used at JET to calculate the foil-activation for the KN2 diagnostics, the angular-fluxes on the lines of sight of the KN3 profile monitors, and general background fluxes and activation of the vessel. The program is used along with MCNP, combining the advantages of each of the programs and for mutual checks. (orig.).

  16. Development of a neutron tomography system using a low flux reactor

    International Nuclear Information System (INIS)

    A neutron tomography instrument was designed and developed at the Royal Military College (RMC) of Canada with Queen's University to enhance these institutions' non-destructive evaluation capabilities. The neutron imaging system was built around a Safe Low-Power C(K)ritical Experiment (SLOWPOKE-2) nuclear research reactor. The low power and physical geometry of the reactor required that a novel design be developed to facilitate tomography. A unique rotisserie style rotary stage and clamping apparatus was developed. Furthermore, the low flux at the image plane (3x104 n cm-2 s-1), necessitated that the image acquisition and reconstruction processes be optimized. Tomographs of numerous samples were obtained using the new tomography instrument at RMC.

  17. A Feasibility Study on the Inspection System Development of Underground Cavities Using Neutron Source

    International Nuclear Information System (INIS)

    The detection efficiency using the gravimetry method is significantly low; therefore, it requires large surveying time. The magnetometry method detects the cavities by the magnitude of the magnetic field. However, the magnetometry method is problematical in urban areas due to pipes and electrical installations. GPR is the method that uses high frequency electromagnetic wave. This method is widely used for the inspection; however, the detection accuracy of sinkholes can be low in specific soil types. In this study, to verify the feasibility of the neutron source-based inspection system to detect the cavity detection, the Monte Carlo simulation was performed using neutron source. The analysis shows that the detection of the cavity with the given condition is possible when the diameter of cavity is over 100 cm. However, the detection efficiency can be enough increased if some optimization strategies for the inspection are developed. Also, it is expected that the proposed inspection method can detect the expected locations of the cavities

  18. A Feasibility Study on the Inspection System Development of Underground Cavities Using Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Che Wook; Kim, Song Hyun; Kim, Do Hyun; Shin, Chang Ho [Hanyang University, Seoul (Korea, Republic of)

    2015-05-15

    The detection efficiency using the gravimetry method is significantly low; therefore, it requires large surveying time. The magnetometry method detects the cavities by the magnitude of the magnetic field. However, the magnetometry method is problematical in urban areas due to pipes and electrical installations. GPR is the method that uses high frequency electromagnetic wave. This method is widely used for the inspection; however, the detection accuracy of sinkholes can be low in specific soil types. In this study, to verify the feasibility of the neutron source-based inspection system to detect the cavity detection, the Monte Carlo simulation was performed using neutron source. The analysis shows that the detection of the cavity with the given condition is possible when the diameter of cavity is over 100 cm. However, the detection efficiency can be enough increased if some optimization strategies for the inspection are developed. Also, it is expected that the proposed inspection method can detect the expected locations of the cavities.

  19. User's manual of a supporting system for treatment planning in boron neutron capture therapy. JAERI computational dosimetry system

    CERN Document Server

    Kumada, H

    2002-01-01

    A boron neutron capture therapy (BNCT) with epithermal neutron beam is expected to treat effectively for malignant tumor that is located deeply in the brain. It is indispensable to estimate preliminarily the irradiation dose in the brain of a patient in order to perform the epithermal neutron beam BNCT. Thus, the JAERI Computational Dosimetry System (JCDS), which can calculate the dose distributions in the brain, has been developed. JCDS is a software that creates a 3-dimensional head model of a patient by using CT and MRI images and that generates a input data file automatically for calculation neutron flux and gamma-ray dose distribution in the brain by the Monte Carlo code: MCNP, and that displays the dose distribution on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By treating CT data and MRI data which are medical images, a detail three-dimensional model of patient's head is able to be made easily. The three-dimensional head image is editable to ...

  20. Spallation Neutron Source Accelerator Facility Target Safety and Non-safety Control Systems

    International Nuclear Information System (INIS)

    The Spallation Neutron Source (SNS) is a proton accelerator facility that generates neutrons for scientific researchers by spallation of neutrons from a mercury target. The SNS became operational on April 28, 2006, with first beam on target at approximately 200 W. The SNS accelerator, target, and conventional facilities controls are integrated by standardized hardware and software throughout the facility and were designed and fabricated to SNS conventions to ensure compatibility of systems with Experimental Physics Integrated Control System (EPICS). ControlLogix Programmable Logic Controllers (PLCs) interface to instruments and actuators, and EPICS performs the high-level integration of the PLCs such that all operator control can be accomplished from the Central Control room using EPICS graphical screens that pass process variables to and from the PLCs. Three active safety systems were designed to industry standards ISA S84.01 and IEEE 603 to meet the desired reliability for these safety systems. The safety systems protect facility workers and the environment from mercury vapor, mercury radiation, and proton beam radiation. The facility operators operated many of the systems prior to beam on target and developed the operating procedures. The safety and non-safety control systems were tested extensively prior to beam on target. This testing was crucial to identify wiring and software errors and failed components, the result of which was few problems during operation with beam on target. The SNS has continued beam on target since April to increase beam power, check out the scientific instruments, and continue testing the operation of facility subsystems

  1. A 10 tesla cryomagnetic system for neutron scattering experiments

    Science.gov (United States)

    Claudet, G.; Gravil, B.; Rossat-Mignod, J.; Burgess, S.

    A cryomagnetic system is described in which the first main component is a cryostat providing variable temperatures and the second a superconducting coil. The cryostat enables the coil to operate at either 4.2 K or 2.16 K, and allows a sample of diameter 10 mm, height 10 mm, to be brought to temperatures varying from 1.5 K to 300 K. The magnet is an asymmetrical split coil with a vertical magnetic axis. Aluminium windows provide access vertically over 15°, horizontally over 340° to a bore of useful diameter 32 mm. The superconducting magnet is wound from multifilamentary NbTi and Nb 3Sn wires and provides a central field of 8.7 T at 4.2 K and 10 T at 2.16 K.

  2. A 10 tesla cryomagnetic system for neutron scattering experiments

    International Nuclear Information System (INIS)

    A cryomagnetic system is described in which the first main component is a cryostat providing variable temperatures and the second a superconducting coil. The cryostat enables the coil to operate at either 4.2 K or 2.16 K, and allows a sample of diameter 10 mm, height 10 mm, to be brought to temperatures varying from 1.5 K to 300 K. The magnet is an asymmetrical split coil with a vertical magnetic axis. Aluminium windows provide access vertically over 150, horizontally over 3400 to a bore of useful diameter 32 mm. The superconducting magnet is wound from multifilamentary NbTi and Nb3Sn wires and provides a central field of 8.7 T at 4.2 K and 10 T at 2.16 K. (author)

  3. Design calculations of an epithermal neutron beam and development of a treatment planning system for the renovation of thor for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Tsing Hua University was recently granted by National Science Council a five-year project to renovate its Open-Pool reactor (THOR) for boron neutron capture therapy. With this support, the whole graphite blocks in the original thermal column region can be removed for redesigning and constructing a better epithermal neutron beam. THOR is a 1 MW research reactor. The cross section area of the core facing the thermal column is 60 cm x 50 cm. By using 60 cm FLUENTAL plus 10 cm Pb, with cross section area of 70 cm x 60 cm and surrounded by 6 cm thick PbF2 reflector, the epithermal neutron flux at the filter/moderator exit can reach ∼8.5 x 109 n/cm2/s. When the collimator is added, the epithermal neutron beam intensity at the beam exit is reduced to 3 x 109 n/cm2/sec, but is still six times higher than the previous beam. Facing the clinical trials scheduled 3 and half years from now, a preliminary version of treatment planning system is developed. It includes a pre-processor to read CT scan and post-processors to display dose distributions. (author)

  4. Development and characterization of a high yield transportable pulsed neutron source with efficient and compact pulsed power system

    Science.gov (United States)

    Verma, Rishi; Mishra, Ekansh; Dhang, Prosenjit; Sagar, Karuna; Meena, Manraj; Shyam, Anurag

    2016-09-01

    The results of characterization experiments carried out on a newly developed dense plasma focus device based intense pulsed neutron source with efficient and compact pulsed power system are reported. Its high current sealed pseudospark switch based low inductance capacitor bank with maximum stored energy of ˜10 kJ is segregated into four modules of ˜2.5 kJ each and it cumulatively delivers peak current in the range of 400 kA-600 kA (corresponding to charging voltage range of 14 kV-18 kV) in a quarter time period of ˜2 μs. The neutron yield performance of this device has been optimized by discretely varying deuterium filling gas pressure in the range of 6 mbar-11 mbar at ˜17 kV/550 kA discharge. At ˜7 kJ/8.5 mbar operation, the average neutron yield has been measured to be in the order of ˜4 × 109 neutrons/pulse which is the highest ever reported neutron yield from a plasma focus device with the same stored energy. The average forward to radial anisotropy in neutron yield is found to be ˜2. The entire system is contained on a moveable trolley having dimensions 1.5 m × 1 m × 0.7 m and its operation and control (up to the distance of 25 m) are facilitated through optically isolated handheld remote console. The overall compactness of this system provides minimum proximity to small as well as large samples for irradiation. The major intended application objective of this high neutron yield dense plasma focus device development is to explore the feasibility of active neutron interrogation experiments by utilization of intense pulsed neutron sources.

  5. A neutron activation system for Ho, HoZr and Sm brachytherapy seeds for breast radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Wagner L., E-mail: wagner.leite@ifmg.edu.br [Instituto Federal de Minas Gerais (IFMG), Congonhas, MG (Brazil). Departamento de Fisica; Campos, Tarcisio P.R., E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2015-07-01

    This paper addresses a device designed for transmuting nuclides by means of neutron capture reactions. The device is composed by a neutron generator based on d-d reactions, a neutron moderator and a reflection system, enclosed by a radiation shield. The project was modeled on the CST electromagnetic code. Afterwards, a nuclear investigation was carried out by MCNP5 code, where the final activities of a large set of 0.5 x 1.8 mm cylindrical, biodegradable and biocompatible, Ho-165 (Ho and HoZr) and Sm-152 breast brachytherapy seeds were evaluated, considering the neutron capture reactions. The accelerator-head equipotential profiles and the optical beam of deuterons with its energy map were presented. The neutronic evaluation allowed estimating a neutron yield of 10{sup 13} n s{sup -1}. From the seed's group, an individual Ho-166 seed reached activity of 100 MBq in 58 h operation time. Moreover, Sm-153 seed reached 120 MBq during a period of 64 h of operation. The system shows to be able to provide the neutron activation of brachytherapy seeds with suitable individual specific activity able for controlling breast tumors. (author)

  6. Monte Carlo modelling of fast neutron scattering by various compounds in view of elaboration of a single shot inspection system

    International Nuclear Information System (INIS)

    Modern, portable or transportable neutron generators, based on the Plasma-Focus principle, are capable to produce a flash of the very intense (up to 109 of 2.45 MeV neutrons from D-D and up to 1011 of 14 MeV neutrons per shot from D-T reactions) and very short neutron pulses (∼ 10 ns). Taking advantage of these capabilities it is possible to determine the elemental content of unknown samples from information existing in a field of scattered neutrons. It allows proposing an alternative approach to the detection of explosives and other illicit materials. The time-of-flight method can be involved in the identification procedure due to the short neutron pulse duration. It is expected that a single shot inspection system can be elaborated on the basis of the proposed method, limited in time only by computer data processing. Results of the Monte Carlo simulations of the scattered neutron field from several compounds (explosives and everyday use materials) are presented in the paper. The MCNP5 code has been used to get info on the angular and energy distributions of neutrons scattered by the above mentioned compounds assuming the initial neutron energy equal to 2.45 MeV (D-D). A new input has been elaborated that allows modeling not only a spectrum of the neutrons scattered at different angles but also their time history from the moment of generation up to detection. Such an approach allows getting approximate signals as registered by hypothetic scintillator+photomultipler probes placed at various distances from the scattering object, demonstrating a principal capability of the method to identify an elemental content of the inspected objects. (author)

  7. 8-channel system for neutron-nuclear investigations by time-of-flight method

    International Nuclear Information System (INIS)

    In connection with commissioning of the IREN pulsed resonance neutron source, new electronics and appropriate software are developed for registration of time-of-flight spectra with small width of the channel (10 ns). The hardware-software system is intended for research of the IREN neutron beam characteristics, properties of new detectors, and also for performance of precision experiments under conditions of low intensity or registration of rare events. The time encoder is the key element of the system hardware. It is developed on the basis of the Cypress-technologies. The unit can measure time intervals for signals intensity up to 105 for each of eight inputs. Using a USB interface provides system mobility. The TOF System Software includes the control program, driver software layer, data sorting program and data processing utilities and other units, performed as executable applications. The interprocess communication between units is provided by network and/or by specially designed interface based on the mechanism of named files mapped into memory. This method provides fastest possible communication between processes. The developed methods of integrating the executable components into a system provide a distributed system, improve the reusing of the software and provide the ability to assemble the system by the user

  8. Basic neutronics. Neutrons migration

    International Nuclear Information System (INIS)

    This article presents the basic neutronics necessary for the understanding of the operation of the different types of nuclear reactors: 1 - introduction to neutronics: principle of fission chain reactions, fast neutron reactors and thermal neutron reactors, capture, neutron status, variations with the reactor lattices; 2 - Boltzmann equation: neutrons population, neutrons migration, characterization of neutrons population and reactions, integral form of the Boltzmann equation, integral-differential form, equivalence between the two forms; 3 - reactor kinetics: fast neutrons and delayed neutrons, kinetic equations in punctual model, Nordheim equation, reactivity jumps, reactivity ramp; 4 - diffusion equation: local neutron status, Fick's law, diffusion equation, initial, boundary and interface conditions, nuclei in infinite and homogenous medium, some examples of solutions, developments in Eigenmodes; 5 - one-group theory: equation of the 'one-group - diffusion' theory, critical condition of the naked and homogenous reactor, critical condition of a reactor with reflectors, generalizations; 6 - neutrons moderation: different moderation mechanisms, elastic shock laws, moderation equation, some examples of solutions; 7 - resonance absorption of neutrons: advantage of the discontinuous moderation character, advantage of an heterogenous disposition, classical formula of the anti-trap factor in homogenous and heterogenous situation; 8 - neutrons thermalization: notions of thermalization mechanisms, thermalization equation, Maxwell spectrum, real spectrum, classical formula of the thermal utilisation factor, classical formula of the reproduction factor, moderation optimum. (J.S.)

  9. Sustainable thorium nuclear fuel cycles: A comparison of intermediate and fast neutron spectrum systems

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.R., E-mail: nbrown@bnl.gov [Brookhaven National Laboratory, Upton, NY (United States); Powers, J.J. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Feng, B.; Heidet, F.; Stauff, N.E.; Zhang, G. [Argonne National Laboratory, Argonne, IL (United States); Todosow, M. [Brookhaven National Laboratory, Upton, NY (United States); Worrall, A.; Gehin, J.C. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Kim, T.K.; Taiwo, T.A. [Argonne National Laboratory, Argonne, IL (United States)

    2015-08-15

    Highlights: • Comparison of intermediate and fast spectrum thorium-fueled reactors. • Variety of reactor technology options enables self-sustaining thorium fuel cycles. • Fuel cycle analyses indicate similar performance for fast and intermediate systems. • Reproduction factor plays a significant role in breeding and burn-up performance. - Abstract: This paper presents analyses of possible reactor representations of a nuclear fuel cycle with continuous recycling of thorium and produced uranium (mostly U-233) with thorium-only feed. The analysis was performed in the context of a U.S. Department of Energy effort to develop a compendium of informative nuclear fuel cycle performance data. The objective of this paper is to determine whether intermediate spectrum systems, having a majority of fission events occurring with incident neutron energies between 1 eV and 10{sup 5} eV, perform as well as fast spectrum systems in this fuel cycle. The intermediate spectrum options analyzed include tight lattice heavy or light water-cooled reactors, continuously refueled molten salt reactors, and a sodium-cooled reactor with hydride fuel. All options were modeled in reactor physics codes to calculate their lattice physics, spectrum characteristics, and fuel compositions over time. Based on these results, detailed metrics were calculated to compare the fuel cycle performance. These metrics include waste management and resource utilization, and are binned to accommodate uncertainties. The performance of the intermediate systems for this self-sustaining thorium fuel cycle was similar to a representative fast spectrum system. However, the number of fission neutrons emitted per neutron absorbed limits performance in intermediate spectrum systems.

  10. Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Kevin James [Univ. of California, Berkeley, CA (United States)

    2010-04-08

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 μm of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles

  11. 3D neutronic codes coupled with thermal-hydraulic system codes for PWR, and BWR and VVER reactors

    Energy Technology Data Exchange (ETDEWEB)

    Langenbuch, S.; Velkov, K. [GRS, Garching (Germany); Lizorkin, M. [Kurchatov-Institute, Moscow (Russian Federation)] [and others

    1997-07-01

    This paper describes the objectives of code development for coupling 3D neutronics codes with thermal-hydraulic system codes. The present status of coupling ATHLET with three 3D neutronics codes for VVER- and LWR-reactors is presented. After describing the basic features of the 3D neutronic codes BIPR-8 from Kurchatov-Institute, DYN3D from Research Center Rossendorf and QUABOX/CUBBOX from GRS, first applications of coupled codes for different transient and accident scenarios are presented. The need of further investigations is discussed.

  12. INDRA: a program system for calculating the neutronics and photonics characteristics of a fusion reactor blanket

    International Nuclear Information System (INIS)

    INDRA is a program system for calculating the neutronics and photonics characteristics of fusion reactor blankets. It incorporates a total of 19 different codes and 5 large data libraries. 10 of the codes are available from the code distribution organizations. Some of them, however, have been slightly modified in order to permit a convenient transfer of information from one program module to the next. The remaining 9 programs have been prepared by the authors to complete the system with respect to flexibility and to facilitate the handling of the results. (orig./WBU)

  13. Studies of light neutron-excess systems from bounds to continuum

    Directory of Open Access Journals (Sweden)

    Ito Makoto

    2011-10-01

    Full Text Available The generalized two-center cluster model (GTCM, which can handle various single particle config urations in general two center systems, is applied to the light neutron-rich system, 12Be= α+α+4N. We discuss the change of the neutrons’ configuratio around two α-cores as a variation of an excitation energy. We show that the covalent, ionic and atomic configuration appear in the unbound region above the α+8Heg.s. particledecay threshold. The GTCM calculation is also applied to even Be isotopes, and the systematics on the structural changes from bound region to continuum is discussed.

  14. The evolution of naked helium stars with a neutron-star companion in close binary systems

    OpenAIRE

    Dewi, J D M; Pols, O. R; Savonije, G.J.; Heuvel, E.P.J. van den

    2002-01-01

    The evolution of helium stars with masses of 1.5 - 6.7 M_sun in binary systems with a 1.4 M_sun neutron-star companion is presented. Such systems are assumed to be the remnants of Be/X-ray binaries with B-star masses in the range of 8 - 20 M_sun which underwent a case B or case C mass transfer and survived the common-envelope and spiral-in process. The orbital period is chosen such that the helium star fills its Roche lobe before the ignition of carbon in the centre. We distinguish case BA (i...

  15. System of Modelling and Calculation Analysis of Neutron- Physical Experiments at Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Moiseyev, A.V. [SSC RF - IPPE, 1 Bondarenko Square, Obninsk, Kaluga Region 249033 (Russian Federation)

    2008-07-01

    There is an actual task on storage, processing and analysis of the unique experimental data received on power fast reactors for their subsequent use in projects of fast reactors of new (4.) generation. For modeling and carrying out analysis of experiments the integrated computing system MODEXSYS has been developed. In this system the mechanism for consecutive calculation of a fast reactor states with the detailed description of its components is created. The system includes the database describing fast reactor states, results of neutron-physical characteristics measurements at fast reactor, calculation and benchmark models of experiments and calculation results. In system convenient search means and the special graphics shell are provided. It has Interfaces for processing of calculation results and their analysis. MODEXSYS system has been applied for analysis of three types of experiments at fast reactor: k{sub eff}, control rod worth and energy release distribution. The most important results of this analysis are described. Application of MODEXSYS system will raise accuracy and reliability of forecasting of fast reactors neutron-physical characteristics; for BN-600 reactor recommended level of accuracy is resulted. (authors)

  16. Mobile neutron/gamma waste assay system for characterization of waste containing transuranics, uranium, and fission/activation products

    International Nuclear Information System (INIS)

    A new integrated neutron/gamma assay system has been built for measuring 55-gallon drums at Pacific Northwest Laboratory. The system is unique because it allows simultaneous measurement of neutrons and gamma-rays. This technique also allows measurement of transuranics (TRU), uranium, and fission/activation products, screening for shielded Special Nuclear Material prior to disposal, and critically determinations prior to transportation. The new system is positioned on a platform with rollers and installed inside a trailer or large van to allow transportation of the system to the waste site instead of movement of the drums to the scanner. The ability to move the system to the waste drums is particularly useful for drum retrieval programs common to all DOE sites and minimizes transportation problems on the site. For longer campaigns, the system can be moved into a facility. The mobile system consists of two separate subsystems: a passive Segmented Gamma Scanner (SGS) and a open-quotes clam-shellclose quotes passive neutron counter. The SGS with high purity germanium detector and 75Se transmission source simultaneously scan the height of the drum allowing identification of unshieled open-quotes hot spotsclose quotes in the drum or segments where the matrix is too dense for the transmission source to penetrate. Dense segments can flag shielding material that could be used to hide plutonium or uranium during the gamma analysis. The passive nuetron counter with JSR-12N Neutron Coincidence Analyzer measures the coincident neutrons from the spontaneous fission of even isotopes of plutonium. Because high-density shielding produces minimal absorption of neutrons, compared to gamma rays, the passive neutron portion of the system can detect shielded SNM. Measurements to evaluate the performance of the system are still underway at Pacific Northwest Laboratory

  17. Monitoring method for neutron flux for a spallation target in an accelerator driven sub-critical system

    Science.gov (United States)

    Zhao, Qiang, He, Zhi-Yong; Yang, Lei; Zhang, Xue-Ying; Cui, Wen-Juan; Chen, Zhi-Qiang; Xu, Hu-Shan

    2016-07-01

    In this paper, we study a monitoring method for neutron flux for the spallation target used in an accelerator driven sub-critical (ADS) system, where a spallation target located vertically at the centre of a sub-critical core is bombarded vertically by high-energy protons from an accelerator. First, by considering the characteristics in the spatial variation of neutron flux from the spallation target, we propose a multi-point measurement technique, i.e. the spallation neutron flux should be measured at multiple vertical locations. To explain why the flux should be measured at multiple locations, we have studied neutron production from a tungsten target bombarded by a 250 MeV-proton beam with Geant4-based Monte Carlo simulations. The simulation results indicate that the neutron flux at the central location is up to three orders of magnitude higher than the flux at lower locations. Secondly, we have developed an effective technique in order to measure the spallation neutron flux with a fission chamber (FC), by establishing the relation between the fission rate measured by FC and the spallation neutron flux. Since this relation is linear for a FC, a constant calibration factor is used to derive the neutron flux from the measured fission rate. This calibration factor can be extracted from the energy spectra of spallation neutrons. Finally, we have evaluated the proposed calibration method for a FC in the environment of an ADS system. The results indicate that the proposed method functions very well. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03010000 and XDA03030000) and the National Natural Science Foundation of China(91426301).

  18. Characterization of the neutron irradiation system for use in the Low-Dose-Rate Irradiation Facility at Sandia National Laboratories.

    Energy Technology Data Exchange (ETDEWEB)

    Franco, Manuel,

    2014-08-01

    The objective of this work was to characterize the neutron irradiation system consisting of americium-241 beryllium (241AmBe) neutron sources placed in a polyethylene shielding for use at Sandia National Laboratories (SNL) Low Dose Rate Irradiation Facility (LDRIF). With a total activity of 0.3 TBq (9 Ci), the source consisted of three recycled 241AmBe sources of different activities that had been combined into a single source. The source in its polyethylene shielding will be used in neutron irradiation testing of components. The characterization of the source-shielding system was necessary to evaluate the radiation environment for future experiments. Characterization of the source was also necessary because the documentation for the three component sources and their relative alignment within the Special Form Capsule (SFC) was inadequate. The system consisting of the source and shielding was modeled using Monte Carlo N-Particle transport code (MCNP). The model was validated by benchmarking it against measurements using multiple techniques. To characterize the radiation fields over the full spatial geometry of the irradiation system, it was necessary to use a number of instruments of varying sensitivities. First, the computed photon radiography assisted in determining orientation of the component sources. With the capsule properly oriented inside the shielding, the neutron spectra were measured using a variety of techniques. A N-probe Microspec and a neutron Bubble Dosimeter Spectrometer (BDS) set were used to characterize the neutron spectra/field in several locations. In the third technique, neutron foil activation was used to ascertain the neutron spectra. A high purity germanium (HPGe) detector was used to characterize the photon spectrum. The experimentally measured spectra and the MCNP results compared well. Once the MCNP model was validated to an adequate level of confidence, parametric analyses was performed on the model to optimize for potential

  19. The measurement of the presampled MTF of a high spatial resolution neutron imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Raymond Lei [Nuclear Engineering Teaching Lab, University of Texas at Austin, Austin, TX (United States)], E-mail: rcao@nist.gov; Biegalski, Steven R. [Nuclear Engineering Teaching Lab, University of Texas at Austin, Austin, TX (United States)

    2007-11-21

    A high spatial resolution neutron imaging device was developed at the Mark II TRIGA reactor at University of Texas at Austin. As the modulation transfer function (MTF) is recognized as a well-established parameter for evaluation of imaging system resolution, the aliasing associated with digital sampling adds complexity to its measurement. Aliasing is especially problematic when using a high spatial resolution micro-channel plate (MCP) neutron detector that has a pixel grid size similar to that of a CCD array. To compensate for the aliasing an angulated edge method was used to evaluate the neutron imaging facility, overcoming aliasing by obtaining an oversampled edge spread function (ESF). Baseline correction was applied to the ESF to remove the noticeable trends and the LSF was multiplied by Hann window to obtain a smoothed version of presampled MTF. The computing procedure is confirmed by visual inspection of a testing phantom; in addition, it is confirmed by comparison to the MTF measurement of a scintillation screen with a known MTF curve.

  20. Three-dimensional neutron source models for toroidal fusion energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Slaybaugh, R.N. [Fusion Technology Institute, University of Wisconsin, 1500 Engineering Dr., Madison, WI 53706 (United States)], E-mail: slaybaugh@wisc.edu; Wilson, P.P.H. [Fusion Technology Institute, University of Wisconsin, 1500 Engineering Dr., Madison, WI 53706 (United States)], E-mail: wilsonp@engr.wisc.edu; El-Guebaly, L.A.; Marriott, E.P. [Fusion Technology Institute, University of Wisconsin, 1500 Engineering Dr., Madison, WI 53706 (United States)

    2009-06-15

    Developments in computer architecture and neutronics code capabilities have enabled high-resolution analysis of complex 3D geometries. Thus, accurately modeling 3D source distributions has become important for nuclear analyses. In this work two methods are described which generate and sample such 3D sources based directly on the plasma parameters of a fusion device and which facilitate the ability to update the neutron source following changes to the plasma physics configuration. The cylindrical mesh method is for toroidally symmetric machines and utilizes data in a standard file format which represents the poloidal magnetic flux on an R-Z grid. The conformal hexahedral mesh method takes plasma physics data generated in an idealized toroidal coordinate system and uses a Jacobian transformation and a functional expansion to generate the source. This work describes each methodology and associated test cases. The cylindrical mesh method was applied to ARIES-RS and the conformal hexahedral mesh method was applied to a uniform torus and ARIES-CS. The results of the test cases indicate that these improved source definitions can have important effects on pertinent engineering parameters, such as neutron wall loading, and should therefore be used for high-resolution nuclear analyses of all toroidal devices.

  1. The measurement of the presampled MTF of a high spatial resolution neutron imaging system

    Science.gov (United States)

    Cao, Raymond Lei.; Biegalski, Steven R.

    2007-11-01

    A high spatial resolution neutron imaging device was developed at the Mark II TRIGA reactor at The University of Texas at Austin. As the modulation transfer function (MTF) is recognized as a well-established parameter for evaluation of imaging system resolution, the aliasing associated with digital sampling adds complexity to its measurement. Aliasing is especially problematic when using a high spatial resolution micro-channel plate (MCP) neutron detector that has a pixel grid size similar to that of a CCD array. To compensate for the aliasing an angulated edge method was used to evaluate the neutron imaging facility, overcoming aliasing by obtaining an oversampled edge spread function (ESF). Baseline correction was applied to the ESF to remove the noticeable trends and the LSF was multiplied by Hann window to obtain a smoothed version of presampled MTF. The computing procedure is confirmed by visual inspection of a testing phantom; in addition, it is confirmed by comparison to the MTF measurement of a scintillation screen with a known MTF curve.

  2. Development of the large neutron imaging system for inertial confinement fusion experiments.

    Science.gov (United States)

    Caillaud, T; Landoas, O; Briat, M; Kime, S; Rossé, B; Thfoin, I; Bourgade, J L; Disdier, L; Glebov, V Yu; Marshall, F J; Sangster, T C

    2012-03-01

    Inertial confinement fusion (ICF) requires a high resolution (~10 μm) neutron imaging system to observe deuterium and tritium (DT) core implosion asymmetries. A new large (150 mm entrance diameter: scaled for Laser MégaJoule [P. A. Holstein, F. Chaland, C. Charpin, J. M. Dufour, H. Dumont, J. Giorla, L. Hallo, S. Laffite, G. Malinie, Y. Saillard, G. Schurtz, M. Vandenboomgaerde, and F. Wagon, Laser and Particle Beams 17, 403 (1999)]) neutron imaging detector has been developed for such ICF experiments. The detector has been fully characterized using a linear accelerator and a (60)Co γ-ray source. A penumbral aperture was used to observe DT-gas-filled target implosions performed on the OMEGA laser facility. [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)] Neutron core images of 14 MeV with a resolution of 15 μm were obtained and are compared to x-ray images of comparable resolution.

  3. Development of the large neutron imaging system for inertial confinement fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Caillaud, T.; Landoas, O.; Briat, M.; Kime, S.; Rosse, B.; Thfoin, I.; Bourgade, J. L.; Disdier, L. [CEA, DAM, DIF, F-91297 Arpajon (France); Glebov, V. Yu.; Marshall, F. J.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

    2012-03-15

    Inertial confinement fusion (ICF) requires a high resolution ({approx}10 {mu}m) neutron imaging system to observe deuterium and tritium (DT) core implosion asymmetries. A new large (150 mm entrance diameter: scaled for Laser MegaJoule [P. A. Holstein, F. Chaland, C. Charpin, J. M. Dufour, H. Dumont, J. Giorla, L. Hallo, S. Laffite, G. Malinie, Y. Saillard, G. Schurtz, M. Vandenboomgaerde, and F. Wagon, Laser and Particle Beams 17, 403 (1999)]) neutron imaging detector has been developed for such ICF experiments. The detector has been fully characterized using a linear accelerator and a {sup 60}Co {gamma}-ray source. A penumbral aperture was used to observe DT-gas-filled target implosions performed on the OMEGA laser facility. [T. R. Boehly, D. L. Brown, R. S. Craxton, R. L. Keck, J. P. Knauer, J. H. Kelly, T. J. Kessler, S. A. Kumpan, S. J. Loucks, S. A. Letzring, F. J. Marshall, R. L. McCrory, S. F. B. Morse, W. Seka, J. M. Soures, and C. P. Verdon, Opt. Commun. 133, 495 (1997)] Neutron core images of 14 MeV with a resolution of 15 {mu}m were obtained and are compared to x-ray images of comparable resolution.

  4. Design and development of an in-line sputtering system and process development of thin film multilayer neutron supermirrors

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, A.; Sampathkumar, R.; Kumar, Ajaya; Bhattacharyya, D.; Sahoo, N. K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lagoo, K. D.; Veerapur, R. D.; Padmanabhan, M.; Puri, R. K. [Division of Remote Handling and Robotics, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Bhattacharya, Debarati; Singh, Surendra; Basu, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2014-12-15

    Neutron supermirrors and supermirror polarizers are thin film multilayer based devices which are used for reflecting and polarizing neutrons in various neutron based experiments. In the present communication, the in-house development of a 9 m long in-line dc sputtering system has been described which is suitable for deposition of neutron supermirrors on large size (1500 mm × 150 mm) substrates and in large numbers. The optimisation process of deposition of Co and Ti thin film, Co/Ti periodic multilayers, and a-periodic supermirrors have also been described. The system has been used to deposit thin film multilayer supermirror polarizers which show high reflectivity up to a reasonably large critical wavevector transfer of ∼0.06 Å{sup −1} (corresponding to m = 2.5, i.e., 2.5 times critical wavevector transfer of natural Ni). The computer code for designing these supermirrors has also been developed in-house.

  5. Numerical study of point spread function of a fast neutron radiography system based on scintillating-fiber array

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ For a scintillating-fiber array fast-neutron radiography system, a point-spread- function computing model was introduced, and the simulation code was developed. The results of calculation show that fast-neutron radiographs vary with the size of fast neutron sources, the size of fiber cross-section and the imaging geometry. The results suggest that the following qualifications are helpful for a good point spread function: The cross-section of scintillating fibers not greater than 200μm×200μm, the size of neutron source as small as a few millimeters, the distance between the source and the scintillating fiber array greater than 1 m, and inspected samples placed as close as possible to the array. The results give suggestions not only to experiment considerations but also to the estimation of spatial resolution for a specific system.

  6. Numerical study of point spread function of a fast neutron radiography system based on scintillating-fiber array

    Institute of Scientific and Technical Information of China (English)

    ZHANG; FaQiang

    2007-01-01

    For a scintillating-fiber array fast-neutron radiography system, a point-spread- function computing model was introduced, and the simulation code was developed. The results of calculation show that fast-neutron radiographs vary with the size of fast neutron sources, the size of fiber cross-section and the imaging geometry. The results suggest that the following qualifications are helpful for a good point spread function: The cross-section of scintillating fibers not greater than 200μm×200μm, the size of neutron source as small as a few millimeters, the distance between the source and the scintillating fiber array greater than 1 m, and inspected samples placed as close as possible to the array. The results give suggestions not only to experiment considerations but also to the estimation of spatial resolution for a specific system.……

  7. Design and development of an in-line sputtering system and process development of thin film multilayer neutron supermirrors

    International Nuclear Information System (INIS)

    Neutron supermirrors and supermirror polarizers are thin film multilayer based devices which are used for reflecting and polarizing neutrons in various neutron based experiments. In the present communication, the in-house development of a 9 m long in-line dc sputtering system has been described which is suitable for deposition of neutron supermirrors on large size (1500 mm × 150 mm) substrates and in large numbers. The optimisation process of deposition of Co and Ti thin film, Co/Ti periodic multilayers, and a-periodic supermirrors have also been described. The system has been used to deposit thin film multilayer supermirror polarizers which show high reflectivity up to a reasonably large critical wavevector transfer of ∼0.06 Å−1 (corresponding to m = 2.5, i.e., 2.5 times critical wavevector transfer of natural Ni). The computer code for designing these supermirrors has also been developed in-house

  8. Monte Carlo studies of accelerator driven systems: energy and spatial distribution of neutrons in multiplying and non-multiplying media

    International Nuclear Information System (INIS)

    The LAHET code system is used to study the behaviour of the spallation neutrons resulting from the interaction of 2.5 GeV/c protons with a massive lead target within a large (∼32 m3) lead and graphite moderating environments. The spatial and energy distribution of the neutrons with presence and absence of a fissile material in Accelerator Driven Systems (ADS) are investigated. It is shown that the energy spectra of the neutrons in graphite and lead moderators are very different and such difference is expected to result in noticeable differences in the nuclear waste transmutation abilities of the ADSs that use graphite and lead for neutron moderation and storage

  9. Tests of a new CCD-camera based neutron radiography detector system at the reactor stations in Munich and Vienna

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Pleinert, H. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schillinger, B. [Technische Univ. Muenchen (Germany); Koerner, S. [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria)

    1997-09-01

    The performance of the new neutron radiography detector designed at PSI with a cooled high sensitive CCD-camera was investigated under real neutronic conditions at three beam ports of two reactor stations. Different converter screens were applied for which the sensitivity and the modulation transfer function (MTF) could be obtained. The results are very encouraging concerning the utilization of this detector system as standard tool at the radiography stations at the spallation source SINQ. (author) 3 figs., 5 refs.

  10. Static and Dynamic Performance of Newly Developed ITER Relevant Insulation Systems after Neutron Irradiation

    Science.gov (United States)

    Prokopec, R.; Humer, K.; Fillunger, H.; Maix, R. K.; Weber, H. W.

    2006-03-01

    Fiber reinforced plastics will be used as insulation systems for the superconducting magnet coils of ITER. The fast neutron and gamma radiation environment present at the magnet location will lead to serious material degradation, particularly of the insulation. For this reason, advanced radiation-hard resin systems are of special interest. In this study various R-glass fiber / Kapton reinforced DGEBA epoxy and cyanate ester composites fabricated by the vacuum pressure impregnation method were investigated. All systems were irradiated at ambient temperature (340 K) in the TRIGA reactor (Vienna) to a fast neutron fluence of 1×1022 m-2 (E>0.1 MeV). Short-beam shear and static tensile tests were carried out at 77 K prior to and after irradiation. In addition, tension-tension fatigue measurements were used in order to assess the mechanical performance of the insulation systems under the pulsed operation conditions of ITER. For the cyanate ester based system the influence of interleaving Kapton layers on the static and dynamic material behavior was investigated as well.

  11. Hunting for Gravitational Waves with Massive Gravitons from Inspiralling Double Neutron Star Systems with Pulsar Clocks

    CERN Document Server

    Wang, Joan Jing

    2014-01-01

    Pulsars, especially millisecond pulsars, are intrinsically very stable celestial clocks, and their great pulse period stability open up a wide range of potential applications to astronomical phenomena, such as a natural detector for very low frequency ($10^{-7}-10^{-9}$ Hz) gravitational waves (GWs) background from supermassive black hole binaries. Double neutron star (DNS) binary systems, containing one or two radio pulsars, lose orbital energy by gravitational radiation, which leads to the orbital shrink. As a result, two neutron stars get closer and closer, during which it contributes to the emission of high frequency GWs of $1-10^4$ Hz. In this paper, we investigate the frequency shift of pulse signal for radio pulsars in DNS system that is induced by the emission of GWs from the system. We point out that the pulse frequency shift of radio signal in these systems can be a potential tool to hunt for the high-frequency GWs, with massive gravitons, from DNS systems, which resorts to a temporal shift of gravi...

  12. Development of a framework for the neutronics analysis system for next generation (Contract research)

    International Nuclear Information System (INIS)

    In JAEA, authors has been promoting the development of an object-oriented next-generation neutronics analysis system in order to reflect the latest methods and models of reactor analysis to basic designs and operations of fast reactors in the efficient and effective way. A purpose of the developing system is to effectively realize requirements that has been difficult to manage in the conventional systems, such as change of analysis targets and change of analysis modeling levels. For the realization of the requirements, the authors adopted the two-layer model which consists of a control layer written in the Python as an object-oriented scripting language and a solver layer in the C++ as a system programming language. After having studied the principle on the two-layer model in the next-generation neutronics analysis system, the authors designed and implemented a library that enabled transparent transfer of data objects between the two layers. In each layer, appropriate numerical library was used for better performance. In the present library, a model proxy was implemented to exchange internal data that is represented in different ways in each layer. With this mechanism of the model proxy, it confirmed that data exchange between the layers can be performed easily and effectively. (author)

  13. Mathematical simulation of a portable system for neutron survey meter test

    International Nuclear Information System (INIS)

    The expansion of prospection activity for oil and natural gas in the Rio de Janeiro State brought an increasing use of neutron area monitors by this sector and consequently an increase in demand for calibration of such instruments. There is a need to ensure the traceability and reliability in calibration conditions, which often are lost due to the transport, operation and manipulation, in addition to some defects. The Laboratory of Neutrons (LN), integrating the National Laboratory for Metrology of Ionizing Radiation (LNMRI/IRD), is developing a portable system for testing of area monitors, which may be carried out by the users of the instruments in places where they are used. The first phase of this project consists in the simulation of the geometry of the system, using computational code, based on method of Monte Carlo, MCNP5. In this simulation, the rates of ambient dose equivalent were defined to sensitize area monitors. The modeling of the source of AmBe 20.35 GBq (550 mCi) was also made in a block of polyethylene to define the thickness of the system. The definition of the geometry of the system and discussions for the use of this system in the field are also presented additionally. (author)

  14. Detector Development for Neutron Imaging System for Radioactive-Waste Analysis (NISRA) with 14 MeV Neutrons

    OpenAIRE

    Schumann, Manuel; Engels, Ralf; Frank, M.; Furletova, Julia; Havenith, Andreas; Kemmerling, Günter; Kettler, John; Mauerhofer, Eric; Schitthelm, Oliver; Vasques, R

    2014-01-01

    Radioactive waste has to undergo a process of quality checking in order to check its conformance with national regulations prior to its transport, intermediate storage and final disposal. Within the quality checking of radioactive waste packages non-destructive assays are required to characterize their radiotoxic and chemotoxic contents. In a cooperation framework Forschungszentrum Jülich, RWTH Aachen University and the Siemens AG are studying the feasibility of a compact Neutron Imaging Syst...

  15. Development of a system for simultaneously generating triple extreme conditions for neutron scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ichimura, Shigeju [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    We have developed new system available for controlling sample environment during the neutron scattering experiments. The system can simultaneously generate triple extreme conditions of low temperature, high magnetic field and high pressure. The system consists of : (1) a liquid-helium cryostat which enables the sample temperature range of 1.7 K to 200 K, (2) a superconducting magnet providing a vertical field up to 5 Tesla with antisymmetric split-coil geometry for polarized-beam experiments, and (3) a non-magnetic clamping high-pressure cell designed with the aim of generating hydrostatic pressure up to 2.5 Gpa. In the workshop, we will report the outline of the system and some results of performance tests using the system at JRR-3M of JAERI. (author)

  16. The Design Performance of the Integrated Spallation Neutron Source Vacuum Control System

    CERN Document Server

    Tang, Johnny Y; Ladd, Peter; Williams, Derrick

    2005-01-01

    The Spallation Neutron Source vacuum control systems have been developed within a collaboration of Lawrence Berkeley National Laboratory(LBNL), Los Alamos National Laboratory(LANL), Thomas Jefferson National Accelerator Facility(TJNAF), and Brookhaven National Laboratory(BNL). Each participating lab is responsible for a different section of the machine. Although a great deal of effort has been made to standardize vacuum instrumentation components and the global control system interfaces, the varied requirements of the different sections of the machine made horizontal integration of the individual vacuum control systems both interesting and challenging. To support commissioning, the SNS control system team and the vacuum group developed a set of test strategies and the interlock schemes that allowed horizontal vacuum system integration to be effectively achieved. The design of the vacuum control interlock scheme developed will be presented together with the results of performance measurements made on these sch...

  17. Microdosimetric studies using a Filtered Fast Neutron Irradiation System of research reactor to application in radiation biology

    International Nuclear Information System (INIS)

    In this work, microdosimetric measurements were performed using a Wall-less Tissue Equivalent Proportional Counter - TEPC with spherical cavity with an inner diameter of 1.27 cm. The TEPC was tilled with pure propane gas, C3H8 at 5.6 kPa (42 Torr) pressure, which is equivalent to 1.3 μm in diameter of unit density tissue. The microdosimetric measurement device was irradiated with fast neutron radiation from Texas A and M University Nuclear Science Center research reactor, in College Station, Texas. The fast neutron beams were emitted with three different power values, 0.5, 1.0 and 2.0 kW. during 1h for both high gain and low gain, totalizing two hours for each power with 0.0083 Gy/min of dose rate. The neutron was filtered using the heavily filtered fast neutron irradiation system (FNIS). from Nuclear Science Center, to obtain a decrease of neutron radiation contamination by gamma ray and so, to gain the neutron microdosimetric spectra as. frequency distribution of lineal energy, dose distribution of lineal energy with good precision, and another quantities as frequency-mean of lineal energy, dose- mean of lineal energy, absorbed dose, equivalent dose and average quality factor of fast neutron. The obtained results were satisfactory, with the neutron microdosimetric spectra showing a gamma ray contamination under 5 %, especially to dose distribution of lineal energy. The results obtained in this work were in agreement when compared with another results from scientific literature, which used another procedure to reduce the neutron contamination by gamma ray. (author)

  18. Experience operating the J-PARC cryogenic hydrogen system for a spallation neutron source

    International Nuclear Information System (INIS)

    At J-PARC, 3 GeV protons with a power of 1 MW are injected onto a mercury target at a repetition rate of 25 Hz, producing fast neutrons via a spallation reaction. The high-energy neutrons are slowed down to thermal and/or cold neutrons in hydrogen moderators, to which supercritical hydrogen is supplied at 1.5 MPa and below 20 K. The nuclear heating is estimated to be 3.75 kW for a proton beam power of 1 MW. The pulsed cold neutron is suitable for crystal and magnetic structural analyses because it has a narrow full-width-half-maximum of approximately 100 μs and a short tail. We developed a cryogenic hydrogen system in which supercritical para-hydrogen circulates at 190 g/s and have operated it since 2008. It has the largest flow rate in the world and can reduce the moderator temperature fluctuation below 3 K. So far, we encountered several problems, although long-lasting operation for more than three months has been carried out. For example, the Great East Japan Earthquake was experienced in March 2011. The interlocking system was able to shutdown the cryogenic hydrogen system automatically as expected. In this study, we describe the operation characteristics and our experiences with the J-PARC cryogenic hydrogen system. The proton beam power was gradually increased to 500 kW in 2015. The trial of 600-kW proton beam operation was successfully achieved in April 2015. It was confirmed that the heater and accumulator developed can mitigate the pressure rise caused by the sudden heat load at the moderators when the proton beams are turned on and off. The dynamic behavior in the hydrogen loop can be also simulated using our simulation code. The pressure rise for a 1-MW proton beam is predicted to be below the allowable pressure rise of 0.1 MPa. We believe that the pressure control system is effective for use with 1-MW proton beam operation. (author)

  19. Monte-Carlo simulations of neutron-induced activation in a Fast-Neutron and Gamma-Based Cargo Inspection System

    Science.gov (United States)

    Bromberger, B.; Bar, D.; Brandis, M.; Dangendorf, V.; Goldberg, M. B.; Kaufmann, F.; Mor, I.; Nolte, R.; Schmiedel, M.; Tittelmeier, K.; Vartsky, D.; Wershofen, H.

    2012-03-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. The induced activity was determined by analyzing the gamma spectra. Based on the calculated radioactive inventory in the container, the dose levels due to the induced gamma radiation were calculated at several distances from the container and in relevant time windows after the irradiation, in order to evaluate the radiation exposure of the cargo handling staff, air crew and passengers during flight. The possibility of remanent long-lived radioactive inventory after cargo is delivered to the client is also of concern and was evaluated.

  20. Two dimensional neutron transport calculation system for plate-reactors: experimental design and qualification with SILOE

    International Nuclear Information System (INIS)

    The main objective of this work is to create a neutronic calculations system for the SILOE-SILOETTE reactors, adaptable to other types of plate reactors. The author presents the methodology and the development of the APOLLO 1D (99 gr.) calculations for the creation of cross sections libraries. After a recall of the Discrete Ordinate Method (DOT), the method accuracy is studied in order to optimize the spatial discretization of the calculations; calculations of DOT 3.5 and of SILOETTE core are conducted and their convergence and costs are examined. DOT calculations of SILOETTE and experimental tests results are then compared

  1. A new method to determine in situ the transmission of a neutron-guide system at a reactor source

    CERN Document Server

    Haan, V O D; Gommers, R M; Labohm, F; Well, A A V; De Leege, P F A; Schebetov, A; Pusenkov, V

    2002-01-01

    In this paper, a description of a new method to determine the transmission of neutron guides after they are installed in a beam-tube at a reactor source is given. The method is based on activation measurements of gold foils at the entrance of the beam-tube and at the exit of the neutron guides compared to Monte-Carlo calculations. In this method, a quality factor is defined as the ratio between the actual transmission and the theoretical maximum attainable transmission. This method is used to determine the quality of an optimised neutron-guide system developed for beam-tube R2 of the HOR. The HOR is a pool-type nuclear research reactor at the Interfaculty Reactor Institute of the Delft University of Technology. It is shown that the quality factors of the newly installed neutron guides are between 0.49 and 0.63.

  2. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering

    Science.gov (United States)

    Benedetto, Antonio; Kearley, Gordon J.

    2016-01-01

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics. PMID:27703184

  3. Cryostat system for investigation on new neutron moderator materials at reactor TRIGA PUSPATI

    Energy Technology Data Exchange (ETDEWEB)

    Dris, Zakaria bin, E-mail: zakariadris@gmail.com [College of Graduate Studies, Universiti Tenaga Nasional (UNITEN), Putrajaya Campus, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor (Malaysia); Centre for Nuclear Energy, Universiti Tenaga Nasional (UNITEN), Putrajaya Campus, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor (Malaysia); Mohamed, Abdul Aziz bin; Hamid, Nasri A. [Centre for Nuclear Energy, Universiti Tenaga Nasional (UNITEN), Putrajaya Campus, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor (Malaysia); Azman, Azraf; Ahmad, Megat Harun Al Rashid Megat; Jamro, Rafhayudi; Yazid, Hafizal [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2016-01-22

    A simple continuous flow (SCF) cryostat was designed to investigate the neutron moderation of alumina in high temperature co-ceramic (HTCC) and polymeric materials such as Teflon under TRIGA neutron environment using a reflected neutron beam from a monochromator. Cooling of the cryostat will be carried out using liquid nitrogen. The cryostat will be built with an aluminum holder for moderator within stainless steel cylinder pipe. A copper thermocouple will be used as the temperature sensor to monitor the moderator temperature inside the cryostat holder. Initial measurements of neutron spectrum after neutron passing through the moderating materials have been carried out using a neutron spectrometer.

  4. Cryostat system for investigation on new neutron moderator materials at reactor TRIGA PUSPATI

    Science.gov (United States)

    Dris, Zakaria bin; Mohamed, Abdul Aziz bin; Hamid, Nasri A.; Azman, Azraf; Ahmad, Megat Harun Al Rashid Megat; Jamro, Rafhayudi; Yazid, Hafizal

    2016-01-01

    A simple continuous flow (SCF) cryostat was designed to investigate the neutron moderation of alumina in high temperature co-ceramic (HTCC) and polymeric materials such as Teflon under TRIGA neutron environment using a reflected neutron beam from a monochromator. Cooling of the cryostat will be carried out using liquid nitrogen. The cryostat will be built with an aluminum holder for moderator within stainless steel cylinder pipe. A copper thermocouple will be used as the temperature sensor to monitor the moderator temperature inside the cryostat holder. Initial measurements of neutron spectrum after neutron passing through the moderating materials have been carried out using a neutron spectrometer.

  5. Neutron measurements in the Vandellòs II nuclear power plant with a Bonner sphere system.

    Science.gov (United States)

    Fernández, F; Bakali, M; Tomás, M; Muller, H; Pochat, J L

    2004-01-01

    In some Spanish nuclear power plants of pressurised water reactor (PWR) type, albedo thermoluminescence dosemeters are used for personal dosimetry while survey meters, based on a thermal-neutron detector inside a cylindrical or spherical moderator, are used for dose rate assessment in routine monitoring. The response of both systems is highly dependent on the energy of the existing neutron fields. They are usually calibrated by means of ISO neutron sources with energy distributions quite different from those encountered at these installations. Spectrometric measurements with a Bonner sphere system (BSS) allow us to determine the reference dosimetric values. The UAB group, under request from the National Coordinated Research Action, was in charge of characterising the neutron fields and evaluating the response of personal dosemeters at several measurement points inside the containment building of the Catalan Nuclear Power Plant Vandellòs II. The neutron fields were characterised at five places using the UAB-BSS and a home made unfolding code called MITOM. The results obtained confirm the presence of low-energy components in the neutron field in most of the selected points. Moreover, we have found no influence of the nuclear fuel burning on the shape of the spectrum.

  6. Dynamic neutron depolarization system for the investigation of time dependent magnetic effects

    International Nuclear Information System (INIS)

    To study magnetic after-effects in ferro- and superparamagnetic materials within a range of about 100 μs - 10s a so-called dynamic neutron depolarization system has been developed that is currently installed at the polarized beam facility of the TRIGA Mark II reactor, Vienna. It allows to measure the time dependence of the polarization change of an initially fully polarized neutron beam on its transmission through a sample exposed to a pulsed magnetic field. A split-pair coil mounted directly on the nitrogen shield of a specially designed helium/nitrogen bath cryostat can be energized up to a maximal induction of 0.25T at a slope of about 103 Ts-1. Sample temperatures in the ranges of 4.2-15K and 77-120K can be established. In order to minimize eddy currents the coil suspension as well as the sample holder are sliced radially. The maximal repetition frequency of the field pulses is 100 Hz which is the upper limit of the multiscaler system we use for a synchronized registration of the beam polarization. First measurements are dealing with the superparamagnetic system Cu-1%Co where single domain cobalt precipitations are expected to give rise to relaxation phenomena well observable with this method. (author)

  7. Formation of the Double Neutron Star System PSR J1930$-$1852

    CERN Document Server

    Shao, Yong

    2015-01-01

    The spin period (185 ms) and period derivative ($1.8\\times10^{-17}\\,\\rm s\\,s^{-1}$) of the double neutron star (DNS) system PSR J1930$-$1852 recently discovered indicate that the pulsar was mildly recycled through the process of Roche-lobe overflow. This system has the longest orbital period (45 days) of the known DNS systems, and can be formed from a helium star-NS binary if the initial mass of the helium star was $ \\lesssim 4.0M_{\\odot} $; otherwise the helium star would never fill its Roche-lobe \\citep{t15}. At the moment of the supernova explosion, the mass of the helium star was $ \\lesssim3.0M_{\\odot} $. We find that the probability distribution of the velocity kick imparted to the new-born neutron star has a maximum at about $30 \\,\\rm km\\,s^{-1}$ (and a tail up to $ 260 \\,\\rm km\\,s^{-1}$), indicating that this NS most probably received a low kick velocity at birth.

  8. A fast large-area position-sensitive time-of-flight neutron detection system

    International Nuclear Information System (INIS)

    A new position-sensitive time-of-flight neutron detection and histograming system has been developed for use at the Intense Pulsed Neutron Source. Spatial resolution of roughly 1 cm x 1 cm and time-of-flight resolution of ∼1 μsec are combined in a detection system which can ultimately be expanded to cover several square meters of active detector area. This system is based on the use of arrays of cylindrical one-dimensional position-sensitive proportional counters, and is capable of collecting the x-y-t data and sorting them into histograms at time-averaged data rates up to ∼300,000 events/sec over the full detector area and with instantaneous data rates up to more than fifty times that. Numerous hardware features have been incorporated to facilitate initial tuning of the position encoding, absolute calibration of the encoded positions, and automatic testing for drifts. 7 refs., 11 figs., 1 tabs

  9. Formation of the Double Neutron Star System PSR J1930-1852

    Science.gov (United States)

    Shao, Yong; Li, Xiang-Dong

    2016-01-01

    The spin period (185 ms) and period derivative (1.8× {10}-17 {{s}} {{{s}}}-1) of the recently discovered double neutron star (DNS) system PSR J1930-1852 indicate that the pulsar was mildly recycled through the process of Roche-lobe overflow. This system has the longest orbital period (45 days) of the known DNS systems, and can be formed from a helium star-NS binary if the initial mass of the helium star was ≲ 4.0{M}⊙ ; otherwise, the helium star would never fill its Roche-lobe. At the moment of the supernova explosion, the mass of the helium star was ≲ 3.0{M}⊙ . We find that the probability distribution of the velocity kick imparted to the new-born neutron star has a maximum at about 30 {km} {{{s}}}-1 (and a tail up to 260 {km} {{{s}}}-1), indicating that this NS probably received a low kick velocity at birth.

  10. A neutron monitoring system for evaluating nuclear safety at the Chernobyl Unit 4 fuel debris

    International Nuclear Information System (INIS)

    The remains of the nuclear fuel that was severely damaged in the 1986 Chernobyl unit 4 accident lie in large masses in the premises under the reactor. The fuel debris exists in the form of dusts, chunks, and lavas, and the quantities are substantial--some rooms contain several tons of fuel. Since there is a possibility of water entering these rooms, there is an obvious concern over criticality safety. Incidents of increased neutron count rates have been noted in the vicinity of nuclear fuel debris. Pacific Northwest National Laboratory (PNNL), under a program funded by the US Department of Energy, responded to this safety concern by assembling a new monitoring system to characterize the radiation environment in the vicinity of major fuel deposits. The new monitoring system will measure the gamma and neutron radiation fields in several locations. The measurement data can be tracked over time to determine the characteristics of the radiation fields and better understand the nuclear safety conditions in the vicinity of the fuel. The monitoring system was designed to provide information that will allow a better interpretation of any future events

  11. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion

    International Nuclear Information System (INIS)

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF

  12. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion.

    Science.gov (United States)

    Simpson, R; Christensen, K; Danly, C; Fatherley, V E; Fittinghoff, D; Grim, G P; Izumi, N; Jedlovec, D; Merrill, F E; Skulina, K; Volegov, P; Wilde, C

    2015-12-01

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF. PMID:26724078

  13. Demonstration of a time-integrated short line of sight neutron imaging system for inertial confinement fusion

    Science.gov (United States)

    Simpson, R.; Christensen, K.; Danly, C.; Fatherley, V. E.; Fittinghoff, D.; Grim, G. P.; Izumi, N.; Jedlovec, D.; Merrill, F. E.; Skulina, K.; Volegov, P.; Wilde, C.

    2015-12-01

    The Neutron Imaging System (NIS) is an important diagnostic for understanding implosions of deuterium-tritium capsules at the National Ignition Facility. While the detectors for the existing system must be positioned 28 m from the source to produce sufficient imaging magnification and resolution, recent testing of a new short line of sight neutron imaging system has shown sufficient resolution to allow reconstruction of the source image with quality similar to that of the existing NIS on a 11.6 m line of sight. The new system used the existing pinhole aperture array and a stack of detectors composed of 2 mm thick high-density polyethylene converter material followed by an image plate. In these detectors, neutrons enter the converter material and interact with protons, which recoil and deposit energy within the thin active layer of the image plate through ionization losses. The described system produces time-integrated images for all neutron energies passing through the pinhole. We present details of the measurement scheme for this novel technique to produce energy-integrated neutron images as well as source reconstruction results from recent experiments at NIF.

  14. Neutron monitoring for radiological protection

    International Nuclear Information System (INIS)

    Neutron monitoring is a subject of increasing general interest and considerable attention is being paid to the development of improved techniques and methods for neutron monitoring. The Agency, therefore, considered it important to prepare a guide on the subject of neutron monitoring for radiation protection purposes. The present Manual is intended for those persons or authorities in Member States, particularly developing countries, who are responsible for the organization of neutron monitoring programmes and practical neutron monitoring. This Manual consequently, deals with topics such as neutron dosimetry, sources of neutrons and neutron detection as well as field instruments and operational systems used in this context

  15. An accelerator-based neutron microbeam system for studies of radiation effects

    OpenAIRE

    Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A.; Bigelow, Alan W.; Akselrod, Mark S.; Sykora, Jeff G.; Brenner, David J.

    2010-01-01

    A novel neutron microbeam is being developed at the Radiological Research Accelerator Facility (RARAF) of Columbia University. The RARAF microbeam facility has been used for studies of radiation bystander effects in mammalian cells for many years. Now a prototype neutron microbeam is being developed that can be used for bystander effect studies. The neutron microbeam design here is based on the existing charged particle microbeam technology at the RARAF. The principle of the neutron microbeam...

  16. A compact DD neutron generator–based NAA system to quantify manganese (Mn) in bone in vivo

    International Nuclear Information System (INIS)

    A deuterium-deuterium (DD) neutron generator–based neutron activation analysis (NAA) system has been developed to quantify metals, including manganese (Mn), in bone in vivo. A DD neutron generator with a flux of up to 3*109 neutrons s−1 was set up in our lab for this purpose. Optimized settings, including moderator, reflector, and shielding material and thickness, were selected based on Monte Carlo (MC) simulations conducted in our previous work. Hand phantoms doped with different Mn concentrations were irradiated using the optimized DD neutron generator irradiation system. The Mn characteristic γ-rays were collected by an HPGe detector system with 100% relative efficiency. The calibration line of the Mn/calcium (Ca) count ratio versus bone Mn concentration was obtained (R2 = 0.99) using the hand phantoms. The detection limit (DL) was calculated to be about 1.05 μg g−1 dry bone (ppm) with an equivalent dose of 85.4 mSv to the hand. The DL can be reduced to 0.74 ppm by using two 100% HPGe detectors. The whole body effective dose delivered to the irradiated subject was calculated to be about 17 μSv. Given the average normal bone Mn concentration of 1 ppm in the general population, this system is promising for in vivo bone Mn quantification in humans. (paper)

  17. On the Integration of a Readout System Dedicated for Neutron Discrimination in Harsh Environment

    Directory of Open Access Journals (Sweden)

    Krit S. Ben

    2016-01-01

    Full Text Available New insights related to the integration of a readout system dedicated for the detection and discrimination of neutrons are presented here. This study takes place in the framework of the I_SMART European project. This system will have to work later in a harsh environment in terms of temperature and radiations, what makes not only the development of specifications for operation and reliability of the components necessary but also the investigation of margins for the interplay of the system. Implementation of the analog conditioning chain at transistor level (AMS (Analog/Mixed Signal 0.35μm CMOS technology is investigated here where electrical performances have been validated at SPICE-level simulations using “Spectre” simulator (SPICE-based under Cadence DFII.

  18. Practical application of passive safety features for the advanced neutron source cooling system

    International Nuclear Information System (INIS)

    The results of a conceptual design study leading to the definition of a reference design for the Advanced Neutron Source (ANS) heavy water cooling system are presented. The objective of this study was to define a cooling system that not only met the ANS goals for operating parameters, reliability, availability, and maintainability, but also used inherent, passive, and diverse features and characteristics to satisfy the ANS internal events core melt goal of -5/yr. The approach taken in this study was to define a cooling system configuration having the minimum basic components and characteristics to satisfy the requirements for normal operation, and then to add only those features necessary to meet the requirements for all emergency design-basis events

  19. A tomography system at the thermal neutron column of the ENEA Casaccia TRIGA reactor

    CERN Document Server

    Rosa, R; Santoro, E; Massari, R; Sangiovanni, G; Storelli, L

    2002-01-01

    The developed system is intended for use at a collimated thermal neutron beam with a flux of about 10 sup 6 n/cm sup 2 s. The system works with a cooled CCD array (192 x 165 pixels) and an intensifier for light from a NE426 scintillator with traditional optical coupling. A fine mechanical regulation system allows an accurate positioning of the tomographer, also ensuring the alignment of the CCD array with the rotation and translation axes. The acquisition of 200 projections is carried out in about 30 min with a reconstruction time (40 min max) depending on the reconstruction-matrix order. Radiography and tomography of significant objects are illustrated. The reconstruction algorithm, including spatial and temporal inhomogeneity corrections and filters, was tested with good results for projections up to 512 x 512 pixels. (orig.)

  20. A tomography system at the thermal neutron column of the ENEA Casaccia TRIGA reactor

    International Nuclear Information System (INIS)

    The developed system is intended for use at a collimated thermal neutron beam with a flux of about 106 n/cm2 s. The system works with a cooled CCD array (192 x 165 pixels) and an intensifier for light from a NE426 scintillator with traditional optical coupling. A fine mechanical regulation system allows an accurate positioning of the tomographer, also ensuring the alignment of the CCD array with the rotation and translation axes. The acquisition of 200 projections is carried out in about 30 min with a reconstruction time (40 min max) depending on the reconstruction-matrix order. Radiography and tomography of significant objects are illustrated. The reconstruction algorithm, including spatial and temporal inhomogeneity corrections and filters, was tested with good results for projections up to 512 x 512 pixels. (orig.)

  1. A study on the excore neutron flux monitoring system for the wide range measurement

    International Nuclear Information System (INIS)

    This paper describes a study in which only one kind of neutron detector were used in the advanced ENFMS. The conceptual design was performed for overall system with unified fission chamber. The system consists of detector, junction box, wide-range amplifier and signal processing device. Also the requirements of 10CFR50 App. R were considered in design. On the other hand, through computer simulation, the characteristics of pulse-count mode and MSV mode was scrutinized and each noise withstanding capability was analyzed. The results say that 3rd moment has the more stable characteristics to background noise than MSV method. Also, to remain the integrity of information against noise, during installation and operation, the overall system of KSNP was analyzed from a view of noise. By administration for the cause of noise and noise-coupling paths, through the full understanding of noise characteristics, the transfer of the noise source can be minimized. (Author)

  2. Establishment of experimental system for 99Mo/99mTc production by neutron activation method

    International Nuclear Information System (INIS)

    The research and development (R and D) on the production of 99Mo/99mTc by neutron activation method ((n, γ) method) using JMTR has been carried out in the Neutron Irradiation and Testing Reactor Center. The specific radioactivity of 99Mo by (n, γ) method is extremely low compared with that by fission method ((n,f) method), and as a result, the radioactive concentration of the obtained 99mTc solution is also low. Focusing on the solvent extraction method with methyl ethyl ketone (MEK) as the recovery method of 99mTc from 99Mo produced by (n, γ) method to solve the problem, we have developed the 99Mo/99mTc separation/extraction/concentration devices, and we have carried out the performance tests with the devices. In this report, in order to establish an experimental system for 99Mo/99mTc production, the R and D results of the system are summarized on the improvement of the devices for high-recovery rate of 99mTc, on the dissolution of the pellets, which is the high-density molybdenum trioxide (MoO3) pellets irradiated in Kyoto University Research Reactor (KUR), on the production of 99mTc, and on the inspection of the recovered 99mTc solutions. (author)

  3. Reconstruction of neutron spectra using neural networks starting from the Bonner spheres spectrometric system

    International Nuclear Information System (INIS)

    The artificial neural networks (RN) have been used successfully to solve a wide variety of problems. However to determine an appropriate set of values of the structural parameters and of learning of these, it continues being even a difficult task. Contrary to previous works, here a set of neural networks is designed to reconstruct neutron spectra starting from the counting rates coming from the detectors of the Bonner spheres system, using a systematic and experimental strategy for the robust design of multilayer neural networks of the feed forward type of inverse propagation. The robust design is formulated as a design problem of Taguchi parameters. It was selected a set of 53 neutron spectra, compiled by the International Atomic Energy Agency, the counting rates were calculated that would take place in a Bonner spheres system, the set was arranged according to the wave form of those spectra. With these data and applying the Taguchi methodology to determine the best parameters of the network topology, it was trained and it proved the same one with the spectra. (Author)

  4. Computer-controlled, chemical separation system for use with neutron-activated samples

    International Nuclear Information System (INIS)

    Neutron activation analysis has proven to be a sensitive technique for the quantitative determination of metals in the parts-per-billion range. While sodium and potassium salt concentrations in sea water and biological materials are on the order of 10,000 ppm, the levels of trace metals range from 1 ppm to 0.1 ppb. The high concentrations and high activities of the salts in these matrices greatly reduce the ability to measure short half-life isotopes such as 2.3 min. 28Al, 3.8 min. 52V and 5.1 min. 66Cu. Post-irradiation separation is often the method of choice for such samples. However, when performed manually this technique is awkward, slow and unsafe. The Basic Automated Separation System (BASS) is a computer-controlled, chemical separation system for use in post-irradiation separations of neutron activated samples. It allows irradiation and separation of high-activated samples without user-intervention

  5. Pulsar J0453+1559: A Double Neutron Star System with a Large Mass Asymmetry

    CERN Document Server

    Martinez, J G; Freire, P C C; Deneva, J S; Jenet, F A; McLaughlin, M A; Bagchi, M; Bates, S D; Ridolfi, A

    2015-01-01

    To understand the nature of supernovae and neutron star (NS) formation, as well as binary stellar evolution and their interactions, it is important to probe the distribution of NS masses. Until now, all double NS (DNS) systems have been measured to have a mass ratio close to unity (q $\\geq$ 0.91). Here we report the measurement of the individual masses of the 4.07-day binary pulsar J0453+1559 from measurements of the rate of advance of periastron and Shapiro delay: The mass of the pulsar is 1.559(5) $M_{\\odot}$ and that of its companion is 1.174(4) $M_{\\odot}$; q = 0.75. If this companion is also a neutron star (NS), as indicated by the orbital eccentricity of the system (e=0.11), then its mass is the smallest precisely measured for any such object. The pulsar has a spin period of 45.7 ms and a spin derivative of 1.8616(7) x$10^-19$; from these we derive a characteristic age of ~ 4.1 x $10^9$ years and a magnetic field of ~ 2.9 x $10^9$ G,i.e, this pulsar was mildly recycled by accretion of matter from the pr...

  6. A ferro-deformation at the open quantum system with protons, Z = 8, neutrons, N = 20: 28O

    CERN Document Server

    Moon, Chang-Bum

    2016-01-01

    We offer a possibility that the nuclear system with protons, Z = 8 has a large deformation at neutrons, N = 20; 28O that is beyond the neutron drip line. According to our previous works [arXiv: 1604.05013, 1604.02786, 1604.01017], it is expected that the ferro-deformation would occur at Z = 8, N = 20 through a shape phase transition at N = 18 out of N =16. The shape transition can be explained in terms of isospin dependent spin-orbital interactions between neutrons in the d3/2 orbital and protons in the d5/2 orbital, by yielding both the neutron and the proton pseudo-shell configurations built on each combined subshells. We argue that such a large deformation at N = 18 would be responsible for the 26O to be unbound, leading to a ground state neutron emitter. The ferro-deformation is mapped on the nuclear chart such that is around the following critical proton, neutron coordinates, (Z, N); (64, 104), (40, 64), (20, 40), (8, 20). This configuration depicts a beautiful pattern coming from a harmonious order in t...

  7. Spin-up/spin-down of neutron star in Be-X-ray binary system GX 304-1

    Science.gov (United States)

    Postnov, K. A.; Mironov, A. I.; Lutovinov, A. A.; Shakura, N. I.; Kochetkova, A. Yu.; Tsygankov, S. S.

    2015-01-01

    We analyse spin-up/spin-down of the neutron star in Be-X-ray binary system GX 304-1 observed by Swift/X-ray telescope (XRT) and Fermi/gamma-ray burst monitor (GBM) instruments in the period of the source activity from 2010 April to 2013 January and discuss possible mechanisms of angular momentum transfer to/from the neutron star. We argue that the neutron star spin-down at quiescent states of the source with an X-ray luminosity of Lx ˜ 1034 erg s-1 between a series of Type I outbursts and spin-up during the outbursts can be explained by quasi-spherical settling accretion on to the neutron star. The outbursts occur near the neutron star periastron passages, where the density is enhanced due to the presence of an equatorial Be-disc tilted to the orbital plane. We also propose an explanation to the counterintuitive smaller spin-up rate observed at higher luminosity in a double-peak Type I outburst due to lower value of the specific angular momentum of matter captured from the quasi-spherical wind from the Be-star by the neutron star moving in an elliptical orbit with eccentricity e ≳ 0.5.

  8. Process and system for detecting and pre-locating a clad failure in a fast neutron nuclear reactor

    International Nuclear Information System (INIS)

    The invention relates to a process and system for detecting and pre-locating a clad failure in the fuel assembly of a fast nuclear reactor cooled by a liquid metal (generally sodium) by counting the delayed neutrons emitted by the fission products escaping from the failed assembly and taken up by the liquid metal. The invention makes it possible considerably to increase sensitivity in the detection of the neutron coming from the fission products. To this effect the process consists in performing a direct measurement of the delayed neutrons in the reactor coolant flow, inside the vessel itself containing this coolant. The measurement device has at least one detector for the neutrons emitted by the fission products carried in the coolant flow as a result of the failed fuel element. This detector is inserted inside the vessel in the coolant flow in an area protected from the neutrons emerging from the core by the coolant volume itself and by structures immersed in the annular space between the core and vessel. Preferably, the neutron detector is formed of a U-235 fission chamber, fitted inside a thimble immersed in the coolant

  9. Monitoring method of neutron flux for the spallation target used in an accelerator driven sub-critical systems

    CERN Document Server

    Zhao, Qiang; Yang, Lei; Zhang, Xueying; Cui, Wenjuan; Chen, Zhiqiang; Xu, Hushan

    2015-01-01

    In this paper, we study the monitoring method of neutron flux for the spallation target used in an accelerator driven sub-critical (ADS) system, where the spallation target located vertically at the centre of a sub-critical core is bombarded vertically by the high-energy protons from an accelerator. First, by considering the characteristics in the spatial variation of neutron flux from the spallation target, we propose the following multi-point measurement technique, i.e. the spallation neutron flux should be measured at multiple vertical locations. To explain why the flux should be measured at multiple locations, we have studied the neutron production from tungsten target bombarded by a 250 MeV-proton beam with the Geant4-based Monte Carlo simulations. The simulation results have indicated that the neutron flux at the central location is up to three orders of magnitude higher than the flux at the lower locations. Secondly, we have developed an effective technique in order to measure the spallation neutron fl...

  10. Investigation of Effects of Neutron Irradiation on Tantalum Alloys for Radioisotope Power System Applications

    International Nuclear Information System (INIS)

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for space nuclear power systems such as Radioisotopic Thermoelectric Generators (RTG) since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. A number of tantalum alloys have been developed over the years to increase high-temperature strength (Ta-10%W) and to reduce creep strain (T-111). These tantalum alloys have demonstrated sufficient high-temperature toughness to survive the increasing high pressures of the RTG's operating environment resulting from the alpha decay of the 238-plutonium dioxide fuel. However, 238-plutonium is also a powerful neutron source. Therefore, the RTG operating environment produces large amounts of 3-helium and neutron displacement damage over the 30 year life of the RTG. The literature to date shows that there has been very little work focused on the mechanical properties of irradiated tantalum and tantalum alloys and none at the fluence levels associated with a RTG operating environment. The minimum, reactor related, work that has been reported shows that these alloys tend to follow trends seen in the behavior of other BCC alloys under irradiation. An understanding of these mechanisms is important for the confident extrapolation of mechanical-property trends to the higher doses and gas levels corresponding to actual service lifetimes. When comparing the radiation effects between samples of Ta-10%W and T-111 (Ta-8%W-2%Hf) subjected to identical neutron fluences and environmental conditions at temperatures <0.3Tm (∼700 deg. C), evidence suggests the possibility that T-111 will exhibit higher levels of internal damage accumulation and degradation of mechanical properties compared to Ta-10%W

  11. Investigation of Effects of Neutron Irradiation on Tantalum Alloys for Radioisotope Power System Applications

    Science.gov (United States)

    Barklay, Chadwick D.; Kramer, Daniel P.; Talnagi, Joseph

    2007-01-01

    Tantalum alloys have been used by the U.S. Department of Energy as structural alloys for space nuclear power systems such as Radioisotopic Thermoelectric Generators (RTG) since the 1960s. Tantalum alloys are attractive for high temperature structural applications due to their high melting point, excellent formability, good thermal conductivity, good ductility (even at low temperatures), corrosion resistance, and weldability. A number of tantalum alloys have been developed over the years to increase high-temperature strength (Ta-10%W) and to reduce creep strain (T-111). These tantalum alloys have demonstrated sufficient high-temperature toughness to survive the increasing high pressures of the RTG's operating environment resulting from the alpha decay of the 238-plutonium dioxide fuel. However, 238-plutonium is also a powerful neutron source. Therefore, the RTG operating environment produces large amounts of 3-helium and neutron displacement damage over the 30 year life of the RTG. The literature to date shows that there has been very little work focused on the mechanical properties of irradiated tantalum and tantalum alloys and none at the fluence levels associated with a RTG operating environment. The minimum, reactor related, work that has been reported shows that these alloys tend to follow trends seen in the behavior of other BCC alloys under irradiation. An understanding of these mechanisms is important for the confident extrapolation of mechanical-property trends to the higher doses and gas levels corresponding to actual service lifetimes. When comparing the radiation effects between samples of Ta-10%W and T-111 (Ta-8%W-2%Hf) subjected to identical neutron fluences and environmental conditions at temperatures <0.3Tm (˜700 °C), evidence suggests the possibility that T-111 will exhibit higher levels of internal damage accumulation and degradation of mechanical properties compared to Ta-10%W.

  12. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    Energy Technology Data Exchange (ETDEWEB)

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  13. Optimum design of a moderator system based on dose calculation for an accelerator driven Boron Neutron Capture Therapy.

    Science.gov (United States)

    Inoue, R; Hiraga, F; Kiyanagi, Y

    2014-06-01

    An accelerator based BNCT has been desired because of its therapeutic convenience. However, optimal design of a neutron moderator system is still one of the issues. Therefore, detailed studies on materials consisting of the moderator system are necessary to obtain the optimal condition. In this study, the epithermal neutron flux and the RBE dose have been calculated as the indicators to look for optimal materials for the filter and the moderator. As a result, it was found that a combination of MgF2 moderator with Fe filter gave best performance, and the moderator system gave a dose ratio greater than 3 and an epithermal neutron flux over 1.0×10(9)cm(-2)s(-1).

  14. Neutron Repulsion

    CERN Document Server

    Manuel, Oliver K

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  15. CARMEN-SYSTEM, Programs System for Thermal Neutron Diffusion and Burnup with Feedback

    International Nuclear Information System (INIS)

    1 - Description of problem or function: CARMEN is a system of programs developed for the neutronic calculation of PWR cycles. It includes the whole chain of analysis from cell calculations to core calculations with burnup. The core calculations are based on diffusion theory with cross sections depending on the relevant space-dependent feedback effects which are present at each moment along the cycles. The diffusion calculations are in one, two or three dimensions and in two energy groups. The feedback effects which are treated locally are: burnup, water density, power density and fission products. In order to study in detail these parameters the core should be divided into as many zones as different cross section sets are expected to be required in order to reproduce reality correctly. A relevant difference in any feedback parameter between zones produces different cross section sets for the corresponding zones. CARMEN is also capable to perform the following calculations: - Multiplication factor by burnup step with fixed boron concentration - Buckling and control rod insertion - Buckling search by burnup step - Boron search by burnup step - Control rod insertion search by burnup step. 2 - Method of solution: The cell code (LEOPARD-TRACA) generates the fuel assembly cross sections versus burnup. This is the basic library to be used in the CARMEN code proper. With a planar distribution guess for power density, water density and fluxes, the macroscopic cross sections by zone are calculated by CARMEN, and then a diffusion calculation is done in the whole geometry. With the distribution of power density, heat accumulated in the coolant and the thermal and fast fluxes determined in the diffusion calculation, CARMEN calculates the values of the most relevant parameters that influence the macroscopic cross sections by zone: burnup, water density, effective fuel temperature and fission product concentrations. If these parameters by zone are different from the reference

  16. Application of DSPs in Data Acquisition Systems for Neutron Scattering Experiments at the IBR—2 Pulsed Reactor

    Institute of Scientific and Technical Information of China (English)

    V.Butenko; B.Gebauer; 等

    2001-01-01

    DSPs are widely used in data acquisition systems on neutron spectrometers at the IBR-2 pulsed reactor.In this report several electronic blocks,based on the DSP of the TMS 320CXXXX family by the TI firm and intended to solve different tasks in DAQ systems,are described.

  17. Application of HVJ envelope system to boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) has been used clinically for the treatment of malignant tumors. Two drugs, p-boronophenylalanine (BPA) and sulfhydral borane (BSH), have been used as boron delivery agents. These drugs seem to be taken up preferentially in solid tumors, but it is uncertain whether therapeutic quantities of boron atoms are taken up by micro-invasive or distant tumor cells. High accumulation and high selective delivery of boron into tumor tissues are the most important requirements to achieve efficient BNCT for malignant tumor. The HVJ envelope (HVJ-E) vector system is a novel fusion-mediated gene delivery system based on inactivated hemagglutinating virus of Japan (HVJ; Sendai virus). Although we developed this vector system for gene transfer, it can also deliver proteins, synthetic oligonucleotides, and drugs. HVJ-liposome, which is liposome fused with HVJ-E, has higher boron trapping efficiency than HVJ-E alone. We report the boron delivery into cultured cells with HVJ-liposome systems. The cellular 10B concentration after 60 min incubation with HVJ-E containing BSH was 24.9 μg/g cell pellet for BHK-21 cells (baby hamster kidney cells) and 19.4 μg/g cell pellet for SCC VII cells (murine squamous cell carcinoma). These concentrations are higher than that of 60 min incubated cells with BSH containing (100μg 10B/ml) medium. These results indicate the HVJ-E fused with tumor cell membrane and rapidly delivered boron agents, and that the HVJ-E-mediated delivery system could be applicable to BNCT. Plans are underway to begin neutron radiation experiments in vivo and in vitro. (author)

  18. Neutronic Analysis on Coolant Options in a Hybrid Reactor System for High Level Waste Transmutation

    International Nuclear Information System (INIS)

    A fusion-fission hybrid reactor (FFHR) which is a combination of plasma fusion tokamak as a fast neutron source and a fission reactor as of fusion blanket is another potential candidate. In FFHR, fusion plasma machine can supply high neutron-rich and energetic 14.1MeV (D, T) neutrons compared to other options. Therefore it has better capability in HLW incineration. While, it has lower requirements compared to pure fusion. Much smaller-sized tokamak can be achievable in a near term because it needs relatively low plasma condition. FFHR has also higher safety potential than fast reactors just as ADSR because it is subcritical reactor system. FFHR proposed up to this time has many design concepts depending on the design purpose. FFHR may also satisfy many design requirement such as energy multiplication, tritium production, radiation shielding for magnets, fissile breeding for self-sustain ability also waste transmutation. Many types of fuel compositions and coolant options have been studied. Effect of choices for fuel and coolant was studied for the transmutation purpose FFHR by our team. In this study LiPb coolant was better than pure Li coolant both for neutron multiplication and tritium breeding. However, performance of waste transmutation was reduced with increased neutron absorption at coolant caused by tritium breeding. Also, LiPb as metal coolant has a problem of massive MHD pressure drop in coolant channels. Therefore, in a previous study, waste transmutation performance was evaluated with light water coolant option which may be a realistic choice. In this study, a neutronic analysis was done for the various coolant options with a detailed computation. One of solutions suggested is to use the pressure tubes inside of first wall and second wall In this work, performance of radioactive waste transmutation was compared with various coolant options. On the whole, keff increases with all coolants except for FLiBe, therefore required fusion power is decreased. In

  19. MCNP6 model of the University of Washington clinical neutron therapy system (CNTS)

    Science.gov (United States)

    Moffitt, Gregory B.; Stewart, Robert D.; Sandison, George A.; Goorley, John T.; Argento, David C.; Jevremovic, Tatjana

    2016-01-01

    A MCNP6 dosimetry model is presented for the Clinical Neutron Therapy System (CNTS) at the University of Washington. In the CNTS, fast neutrons are generated by a 50.5 MeV proton beam incident on a 10.5 mm thick Be target. The production, scattering and absorption of neutrons, photons, and other particles are explicitly tracked throughout the key components of the CNTS, including the target, primary collimator, flattening filter, monitor unit ionization chamber, and multi-leaf collimator. Simulations of the open field tissue maximum ratio (TMR), percentage depth dose profiles, and lateral dose profiles in a 40 cm  ×  40 cm  ×  40 cm water phantom are in good agreement with ionization chamber measurements. For a nominal 10  ×  10 field, the measured and calculated TMR values for depths of 1.5 cm, 5 cm, 10 cm, and 20 cm (compared to the dose at 1.7 cm) are within 0.22%, 2.23%, 4.30%, and 6.27%, respectively. For the three field sizes studied, 2.8 cm  ×  2.8 cm, 10.4 cm  ×  10.3 cm, and 28.8 cm  ×  28.8 cm, a gamma test comparing the measured and simulated percent depth dose curves have pass rates of 96.4%, 100.0%, and 78.6% (depth from 1.5 to 15 cm), respectively, using a 3% or 3 mm agreement criterion. At a representative depth of 10 cm, simulated lateral dose profiles have in-field (⩾10% of central axis dose) pass rates of 89.7% (2.8 cm  ×  2.8 cm), 89.6% (10.4 cm  ×  10.3 cm), and 100.0% (28.8 cm  ×  28.8 cm) using a 3% and 3 mm criterion. The MCNP6 model of the CNTS meets the minimum requirements for use as a quality assurance tool for treatment planning and provides useful insights and information to aid in the advancement of fast neutron therapy.

  20. Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Kevin James [Univ. of California, Berkeley, CA (United States)

    2010-04-08

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 μm of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles

  1. A comparison of different neutron spectroscopy systems at the reactor facility VENUS

    CERN Document Server

    Vanhavere, F; Chartier, J L; Itie, C; Rosenstock, W; Koeble, T; D'Errico, F

    2002-01-01

    The VENUS facility is a zero-power research reactor mainly devoted to studies on LWR fuels. Localised high-neutron rates were found around the reactor, with a neutron/gamma dose equivalent rate ratio as high as three. Therefore, a study of the neutron dosimetry around the reactor was started some years ago. During this study, several methods of neutron spectroscopy were employed and a study of individual and ambient dosemeters was performed. A first spectrometric measurement was done with the IPSN multisphere spectrometer in three positions around the reactor. Secondly, the ROSPEC spectrometer from the Fraunhofer Institut was used. The spectra were also measured with the bubble interactive neutron spectrometer. These measurements were compared with a numerical simulation of the neutron field made with the code TRIPOLI-3. Dosimetric measurements were made with three types of personal neutron dosemeters: an albedo type, a track etch detector and a bubble detector.

  2. Integrated system for production of neutronics and photonics calculational constants. Major neutron-induced interactions (Z > 55): graphical, experimental data

    International Nuclear Information System (INIS)

    This report (vol. 7) presents graphs of major neutron-induced interaction cross sections in the Experimental Cross Section Information Library (ECSIL) as of July 4, 1976. It consists primarily of interactions where a single data set contains enough points to show cross section behavior. In contrast, vol. 8 of this UCRL-50400 series consists of interactions where more than one data set is needed to show cross section behavior. Thus, you can find the total, elastic, capture, and fission cross sections (along with the parameters ν bar, α, and eta) in vol. 7 and all other reactions in vol. 8. Data are plotted with associated cross section error bars (when given) and compared with the Evaluated Nuclear Data Library (ENDL) as of July 4, 1976. The plots are arranged in ascending order of atomic number (Z) and atomic weight (A). Part A contains the plots for Z = 1 to 55; Part B contains the plots for Z is greater than 55

  3. Integrated system for production of neutronics and photonics calculational constants. Supplemental neutron-induced interactions (Z > 35): graphical, experimental data

    International Nuclear Information System (INIS)

    This report (vol. 8) presents graphs of supplemental neutron-induced cross sections in the Experimental Cross Section Information Library (ECSIL) as of July 4, 1976. It consists of interactions where more than one data set is needed to show cross-section behavior. In contrast, vol. 7 of this UCRL-50400 series consists primarily of interactions where a single data set contains enough points to show cross-section behavior. Vol. 7 contains total, elastic, capture, and fission cross sections (along with the parameters anti ν, α, and eta). Volume 8 contains all other reactions. Data are plotted with associated cross-section error bars (when given) and compared with the Evaluated Nuclear Data Library (ENDL) as of July 4, 1976. The plots are arranged in ascending order of atomic number (Z) and atomic weight (A). Part A contains the plots for Z = 1 to 35; Part B contains the plots for Z greater than 35

  4. Data acquisition and experiment control system for a large area neutron detector

    International Nuclear Information System (INIS)

    The system consists of a data input subsystem, a display subsystem and a spectrometer control subsystem. The data input subsystem consists of a two-dimensional analog-to-digital converter with the analog section remote from the rest of the system. The analog-to-digital converter clock runs at 100 MHz. There can be up to 1024 channels in each dimension for a maximum array size of approx. 1 million words. Arrays of this size may be easily handled by a multiport memory with 6.71 x 107 words of address space. The read/increment/write time for data in this array is 2.5 μsec per event. The display and neutron spectrometer subsystem are also briefly described

  5. Project and construction of a pneumatic system for the transference of samples to a neutron generator

    International Nuclear Information System (INIS)

    A prototype of a system for the transport of irradiated samples to and from a neutron generator, was constructed, using compressed air as propeller agent. Compressed air was injected through electrically driven values. The sample, transported by the pressure wave, was inserted into a PVC tube 50m long and weighing 23.0 g. The first tests were carried out in order to determine the times needed to transport the above-mentioned PVC support along a PVC tube of 3m length and 3/4 diameter for different air pressures applied; it was verified that for pressures between 3.0 and 8.0 kgf/cm2, transport times were always smaller than 2 seconds. These results showed the viability of constructing a definitive system, already projected. (C.L.B.)

  6. Review and Assessment of Neutron Cross Section and Nubar Covariances for Advanced Reactor Systems

    Energy Technology Data Exchange (ETDEWEB)

    Maslov,V.M.; Oblozinsky, P.; Herman, M.

    2008-12-01

    In January 2007, the National Nuclear Data Center (NNDC) produced a set of preliminary neutron covariance data for the international project 'Nuclear Data Needs for Advanced Reactor Systems'. The project was sponsored by the OECD Nuclear Energy Agency (NEA), Paris, under the Subgroup 26 of the International Working Party on Evaluation Cooperation (WPEC). These preliminary covariances are described in two recent BNL reports. The NNDC used a simplified version of the method developed by BNL and LANL that combines the recent Atlas of Neutron Resonances, the nuclear reaction model code EMPIRE and the Bayesian code KALMAN with the experimental data used as guidance. There are numerous issues involved in these estimates of covariances and it was decided to perform an independent review and assessment of these results so that better covariances can be produced for the revised version in future. Reviewed and assessed are uncertainties for fission, capture, elastic scattering, inelastic scattering and (n,2n) cross sections as well as prompt nubars for 15 minor actinides ({sup 233,234,236}U, {sup 237}Np, {sup 238,240,241,242}Pu, {sup 241,242m,243}Am and {sup 242,243,244,245}Cm) and 4 major actinides ({sup 232}Th, {sup 235,238}U and {sup 239}Pu). We examined available evaluations, performed comparison with experimental data, taken into account uncertainties in model parameterization and made use state-of-the-art nuclear reaction theory to produce the uncertainty assessment.

  7. A prototype fully digital data acquisition system upgrade for the TOFOR neutron spectrometer at JET

    Science.gov (United States)

    Skiba, Mateusz; Ericsson, Göran; Hjalmarsson, Anders; Hellesen, Carl; Conroy, Sean; Andersson-Sundén, Erik; Eriksson, Jacob; JET Contributors

    2016-10-01

    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.

  8. Feasibility studies on explosive detection and homeland security applications using a neutron and x-ray combined computed tomography system

    Science.gov (United States)

    Sinha, V.; Srivastava, A.; Lee, H. K.; Liu, X.

    2013-05-01

    The successful creation and operation of a neutron and X-ray combined computed tomography (NXCT) system has been demonstrated by researchers at the Missouri University of Science and Technology. The NXCT system has numerous applications in the field of material characterization and object identification in materials with a mixture of atomic numbers represented. Presently, the feasibility studies have been performed for explosive detection and homeland security applications, particularly in concealed material detection and determination of the light atomic number materials. These materials cannot be detected using traditional X-ray imaging. The new system has the capability to provide complete structural and compositional information due to the complementary nature of X-ray and neutron interactions with materials. The design of the NXCT system facilitates simultaneous and instantaneous imaging operation, promising enhanced detection capabilities of explosive materials, low atomic number materials and illicit materials for homeland security applications. In addition, a sample positioning system allowing the user to remotely and automatically manipulate the sample makes the system viable for commercial applications. Several explosives and weapon simulants have been imaged and the results are provided. The fusion algorithms which combine the data from the neutron and X-ray imaging produce superior images. This paper is a compete overview of the NXCT system for feasibility studies of explosive detection and homeland security applications. The design of the system, operation, algorithm development, and detection schemes are provided. This is the first combined neutron and X-ray computed tomography system in operation. Furthermore, the method of fusing neutron and X-ray images together is a new approach which provides high contrast images of the desired object. The system could serve as a standardized tool in nondestructive testing of many applications, especially in

  9. Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System

    CERN Document Server

    Bromberger, B; Brandis, M; Dangendorf, V; Goldberg, M B; Kaufmann, F; Mor, I; Nolte, R; Schmiedel, M; Tittelmeier, K; Vartsky, D; Wershofen, H

    2012-01-01

    An air cargo inspection system combining two nuclear reaction based techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy Gamma Radiography is currently being developed. This system is expected to allow detection of standard and improvised explosives as well as special nuclear materials. An important aspect for the applicability of nuclear techniques in an airport inspection facility is the inventory and lifetimes of radioactive isotopes produced by the neutron and gamma radiation inside the cargo, as well as the dose delivered by these isotopes to people in contact with the cargo during and following the interrogation procedure. Using MCNPX and CINDER90 we have calculated the activation levels for several typical inspection scenarios. One example is the activation of various metal samples embedded in a cotton-filled container. To validate the simulation results, a benchmark experiment was performed, in which metal samples were activated by fast-neutrons in a water-filled glass jar. T...

  10. Neutron Scintillators for Downscattered Neutron Imaging

    International Nuclear Information System (INIS)

    Images of neutron emission from Inertial Confinement Fusion (ICF) (D,T) targets reveal the internal structure of the target during the fusion burn. 14-MeV neutrons provide images which show the size and shape of the region where (D,T) fusion is most intense. Images based on ''downscattered'' neutrons with energies from 5 to 10 MeV emphasize the distribution of deuterium and tritium fuel within the compressed target. The downscattered images are difficult to record because the lower energy neutrons are detected with less efficiency than the much more intense pulse of 14-MeV neutrons which precedes them at the detector. The success of downscattered neutron imaging will depend on the scintillation decay times and the sensitivities to lower-energy neutrons of the scintillator materials that are used in the detectors. A time-correlated photon counting system measured the decay of neutron-induced scintillation for times as long as several hundred ns. Accelerators at the University of California, Berkeley, and the Lawrence Livermore National Laboratory provided stable 14-MeV neutron sources for the measurements. Measurements of scintillator decay characteristics indicate that some commercially available scintillators should be suitable for recording both 14-MeV and downscattered neutron images of compressed ICF targets

  11. Design and development of a neutron/X-ray combined computed tomography system at Missouri S and T

    International Nuclear Information System (INIS)

    A new method for non-destructive analysis has been developed using a combined neutron/X-ray imaging system at the Missouri Science and Technology Reactor (MSTR). The interactions of neutrons and X-ray photons with matter produce differing characteristic information, resulting in distinctly different visual images. In order to obtain a more comprehensive picture of the structural and compositional data for a desired object, a prototype imaging system has been designed which utilizes neutron and X-ray imaging simultaneously without obstructing the beam geometry for each imaging mechanism. The current system is optimized for the imaging of small to medium sized objects of 0.5-50 mm. This new imaging capability in place at the MSTR promises great advances in the field of non-destructive testing, especially for nuclear engineering, nuclear medical science, and material science research. In an imaging object, a range of atomic number values and thermal cross-sections may be present. Where multiple materials having similar atomic number and differing thermal cross-section or vice versa may be present, exclusive neutron or X-ray analysis may exhibit shortcomings in distinguishing interfaces. However, fusing the neutron image and X-ray image into a combined image offers the strengths of both and may provide a superior method of analysis. In this paper, a novel combined X-ray and neutron imaging system will be introduced for superior analysis of certain imaging objects. Design details of experimental set-up and examples of preliminary imaging tests from individual modality will be detailed. (author)

  12. Design and initial 1D radiography tests of the FANTOM mobile fast-neutron radiography and tomography system

    International Nuclear Information System (INIS)

    The FANTOM system is a tabletop sized fast-neutron radiography and tomography system newly developed at the Applied Nuclear Physics Division of Uppsala University. The main purpose of the system is to provide time-averaged steam-and-water distribution measurement capability inside the metallic structures of two-phase test loops for light water reactor thermal–hydraulic studies using a portable fusion neutron generator. The FANTOM system provides a set of 1D neutron transmission data, which may be inserted into tomographic reconstruction algorithms to achieve a 2D mapping of the steam-and-water distribution. In this paper, the selected design of FANTOM is described and motivated. The detector concept is based on plastic scintillator elements, separated for spatial resolution. Analysis of pulse heights on an event-to-event basis is used for energy discrimination. Although the concept allows for close stacking of a large number of detector elements, this demonstrator is equipped with only three elements in the detector and one additional element for monitoring the yield from the neutron generator. The first measured projections on test objects of known configurations are presented. These were collected using a Sodern Genie 16 neutron generator with an isotropic yield of about 1E8 neutrons per second, and allowed for characterization of the instrument's capabilities. At an energy threshold of 10 MeV, the detector offered a count rate of about 500 cps per detector element. The performance in terms of spatial resolution was validated by fitting a Gaussian Line Spread Function to the experimental data, a procedure that revealed a spatial unsharpness in good agreement with the predicted FWHM of 0.5 mm

  13. Design and initial 1D radiography tests of the FANTOM mobile fast-neutron radiography and tomography system

    Science.gov (United States)

    Andersson, P.; Valldor-Blücher, J.; Andersson Sundén, E.; Sjöstrand, H.; Jacobsson-Svärd, S.

    2014-08-01

    The FANTOM system is a tabletop sized fast-neutron radiography and tomography system newly developed at the Applied Nuclear Physics Division of Uppsala University. The main purpose of the system is to provide time-averaged steam-and-water distribution measurement capability inside the metallic structures of two-phase test loops for light water reactor thermal-hydraulic studies using a portable fusion neutron generator. The FANTOM system provides a set of 1D neutron transmission data, which may be inserted into tomographic reconstruction algorithms to achieve a 2D mapping of the steam-and-water distribution. In this paper, the selected design of FANTOM is described and motivated. The detector concept is based on plastic scintillator elements, separated for spatial resolution. Analysis of pulse heights on an event-to-event basis is used for energy discrimination. Although the concept allows for close stacking of a large number of detector elements, this demonstrator is equipped with only three elements in the detector and one additional element for monitoring the yield from the neutron generator. The first measured projections on test objects of known configurations are presented. These were collected using a Sodern Genie 16 neutron generator with an isotropic yield of about 1E8 neutrons per second, and allowed for characterization of the instrument's capabilities. At an energy threshold of 10 MeV, the detector offered a count rate of about 500 cps per detector element. The performance in terms of spatial resolution was validated by fitting a Gaussian Line Spread Function to the experimental data, a procedure that revealed a spatial unsharpness in good agreement with the predicted FWHM of 0.5 mm.

  14. Simulation of complete neutron scattering experiments: from model systems to liquid germanium; Simulation complete d'une experience de diffusion de neutrons: des systemes modeles au germanium liquide

    Energy Technology Data Exchange (ETDEWEB)

    Hugouvieux, V

    2004-11-15

    In this thesis, both theoretical and experimental studies of liquids are done. Neutron scattering enables structural and dynamical properties of liquids to be investigated. On the theoretical side, molecular dynamics simulations are of great interest since they give positions and velocities of the atoms and the forces acting on each of them. They also enable spatial and temporal correlations to be computed and these quantities are also available from neutron scattering experiments. Consequently, the comparison can be made between results from molecular dynamics simulations and from neutron scattering experiments, in order to improve our understanding of the structure and dynamics of liquids. However, since extracting reliable data from a neutron scattering experiment is difficult, we propose to simulate the experiment as a whole, including both instrument and sample, in order to gain understanding and to evaluate the impact of the different parasitic contributions (absorption, multiple scattering associated with elastic and inelastic scattering, instrument resolution). This approach, in which the sample is described by its structure and dynamics as computed from molecular dynamics simulations, is presented and tested on isotropic model systems. Then liquid germanium is investigated by inelastic neutron scattering and both classical and ab initio molecular dynamics simulations. This enables us to simulate the experiment we performed and to evaluate the influence of the contributions from the instrument and from the sample on the detected signal. (author)

  15. On The Deign And Construction Of A Radiation Shielding System For Development Of Neutron Beams Based On The Horizontal Channel No.2 Of Dalat Reactor

    International Nuclear Information System (INIS)

    An optimal structural system of filtered neutron beam and radiation shielding has been designed and calculated using the Monte-Carlo code MCNP5. The system was constructed and installed into the horizontal channel No. 2 of the Dalat reactor. The neutron beam is applied for experimental studies on nuclear physics, nuclear data measurements, and personal training. (author)

  16. Neutronic studies for the optimization of shield wall penetrations for laser IFE systems

    Energy Technology Data Exchange (ETDEWEB)

    Lafuente, A., E-mail: Lafuentemazu2@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Latkowski, J.F.; Kramer, K.J.; Dunne, A.M. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer We provide insight on the impact of wall shield penetrations for IFE systems. Black-Right-Pointing-Pointer We establish guidelines for the selection of different variables linked to the pinhole's design. Black-Right-Pointing-Pointer We identify the requirements to enable manual maintenance during operation and propose the use of non-aligned double shield walls with pinholes. - Abstract: Building upon the inertial confinement fusion (ICF) technology developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), a laser-driven inertial fusion energy (LIFE) power plant is being designed. In this pre-conceptual design, the final optic is exposed to a variety of threats originating from the fusion target. These include prompt neutron and gamma fluxes, x-ray and ionic emissions. While x-rays and ions are stopped by the low-density chamber fill gas (6 {mu}g/cc xenon), neutrons and gamma-rays are not significantly attenuated. In order to limit the consequences of such threats onto the penultimate optic and the rest of the laser systems, a shielding wall stands between the target chamber area and the laser bay. An optical telescope arrangement allows for the laser beam propagation from the penultimate to the final optic, through a pinhole in the shielding wall. These pinholes attenuate the neutron flux and reduce effective dose rates such that laser bay maintenance can be performed by humans. An optimum design of this laser pinhole requires a good understanding of the different design trade-offs that exist between shielding performance and survivability of the laser optical elements and are outlined in this work. This paper provides insight on the impact and influence of the pinholes on the radiation doses in the laser bay, which is located on the opposite side of the concrete shielding wall. After addressing the difficulties of evaluating shields containing penetrations, it establishes a

  17. ACCELERATOR SYSTEMS MODIFICATIONS FOR A SECOND TARGET STATION AT THE OAK RIDGE SPALLATION NEUTRON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, John D [ORNL; Kim, Sang-Ho [ORNL; Plum, Michael A [ORNL

    2014-01-01

    A second target station is planned for the Oak Ridge Spallation Neutron Source. The ion source will be upgraded to increase the peak current from 38 to 49 mA, additional superconducting RF cavities will be added to the linac to increase the H beam energy from 938 to 1300 MeV, and the accumulator ring will receive modifications to the injection and extraction systems to accommodate the higher beam energy. After pulse compression in the storage ring one sixth of the beam pulses (10 out of 60 Hz) will be diverted to the second target by kicker and septum magnets added to the existing Ring to Target Beam Transport (RTBT) line. No further modifications will be made to the RTBT so that when the kicker and septum magnets are turned off the original beam transport lattice will be unaffected. In this paper we will discuss these and other planned modifications and upgrades to the accelerator facility.

  18. High Mass X-ray Binaries: Progenitors of double neutron star systems

    CERN Document Server

    Chaty, Sylvain

    2015-01-01

    In this review I briefly describe the nature of the three kinds of High-Mass X-ray Binaries (HMXBs), accreting through: (i) Be circumstellar disc, (ii) supergiant stellar wind, and (iii) Roche lobe filling supergiants. A previously unknown population of HMXBs hosting supergiant stars has been revealed in the last years, with multi-wavelength campaigns including high energy (INTEGRAL, Swift, XMM, Chandra) and optical/infrared (mainly ESO) observations. This population is divided between obscured supergiant HMXBs, and supergiant fast X-ray transients (SFXTs), characterized by short and intense X-ray flares. I discuss the characteristics of these types of supergiant HMXBs, propose a scenario describing the properties of these high-energy sources, and finally show how the observations can constrain the accretion models (e.g. clumpy winds, magneto-centrifugal barrier, transitory accretion disc, etc). Because they are the likely progenitors of Luminous Blue Variables (LBVs), and also of double neutron star systems,...

  19. Spin-up/spin-down of neutron star in Be-X-ray binary system GX 304-1

    CERN Document Server

    Postnov, K A; Lutovinov, A A; Shakura, N I; Kochetkova, A Yu; Tsygankov, S S

    2014-01-01

    We analyze spin-up/spin-down of the neutron star in Be X-ray binary system GX\\,304-1 observed by \\textit{Swift}/XRT and \\textit{Fermi}/GBM instruments in the period of the source activity from April 2010 to January 2013 and discuss possible mechanisms of angular momentum transfer to/from the neutron star. We argue that the neutron star spin-down at quiescent states of the source with an X-ray luminosity of $L_x\\sim 10^{34}$~erg s$^{-1}$ between a series of Type I outbursts and spin-up during the outbursts can be explained by quasi-spherical settling accretion onto the neutron star. The outbursts occur near the neutron star periastron passages where the density is enhanced due to the presence of an equatorial Be-disc tilted to the orbital plane. We also propose an explanation to the counterintuitive smaller spin-up rate observed at higher luminosity in a double-peak Type I outburst due to lower value of the specific angular momentum of matter captured from the quasi-spherical wind from the Be-star by the neutr...

  20. Neutron cross-sections above 20 MeV for design and modeling of accelerator driven systems

    Science.gov (United States)

    Blomgren, J.

    2007-02-01

    One of the outstanding new developments in the field of partitioning and transmutation (P{&}T) concerns accelerator-driven systems (ADS) which consist of a combination of a high-power, high-energy accelerator, a spallation target for neutron production and a sub-critical reactor core. The development of the commercial critical reactors of today motivated a large effort on nuclear data up to about 20 MeV, and presently several million data points can be found in various data libraries. At higher energies, data are scarce or even non-existent. With the development of nuclear techniques based on neutrons at higher energies, nowadays there is a need also for higher-energy nuclear data. To provide alternative to this lack of data, a wide program on neutron-induced data related to ADS for P{&}T is running at the 20-180 MeV neutron beam facility at `The Svedberg Laboratory' (TSL), Uppsala. The programme encompasses studies of elastic scattering, inelastic neutron production, i.e., (n, xn') reactions, light-ion production, fission and production of heavy residues. Recent results are presented and future program of development is outlined.

  1. Construction and testing of a neutron and gamma spectrometry system using pulse shape discrimination with an organic scintillator

    Science.gov (United States)

    Pope, Robert S.

    1993-03-01

    The goal of this thesis was to construct and test a neutron detector to measure the energy spectrum of 1 to 14-MeV neutrons in the presence of gammas. A spectrometer based on the process of pulse shape discrimination (PSD) was constructed, in which the scintillator NE-213 was used. The primary neutron/gamma sources used were 78-mCi and 4.7-Ci Pu-239Be sources, while 4.7-micro-Ci and 97.6-micro-Ci Na-22 gamma sources were used for energy calibration and additional testing of the detector. Proton recoil spectra and Compton electron spectra were unfolded with the neutron and gamma unfolding code FORIST to generate the incident neutron and gamma spectra, respectively. FORIST, which was written for a CDC computer, was modified to run on a VAX 6420. The experimental spectra were compared to those in the literature. The locations of the peaks in the Pu-239Be spectrum agreed with the literature to within 8.3%, the Pu-239Be gamma spectrum agreed to within 0.7%, while the Na-22 gamma spectrum agreed exactly. Uncertainties in the detection system and unfolding procedure are on the order of 5-10%. This thesis is intended to be a summary of the relevant literature and a user's guide to the PSD spectrometer.

  2. Neutron cross-sections above 20 MeV for design and modeling of accelerator driven systems

    Indian Academy of Sciences (India)

    J Blomgren

    2007-02-01

    One of the outstanding new developments in the field of partitioning and transmutation (P&T) concerns accelerator-driven systems (ADS) which consist of a combination of a high-power, high-energy accelerator, a spallation target for neutron production and a sub-critical reactor core. The development of the commercial critical reactors of today motivated a large effort on nuclear data up to about 20 MeV, and presently several million data points can be found in various data libraries. At higher energies, data are scarce or even non-existent. With the development of nuclear techniques based on neutrons at higher energies, nowadays there is a need also for higher-energy nuclear data. To provide alternative to this lack of data, a wide program on neutron-induced data related to ADS for P&T is running at the 20–180 MeV neutron beam facility at `The Svedberg Laboratory' (TSL), Uppsala. The programme encompasses studies of elastic scattering, inelastic neutron production, i.e., (, ′) reactions, light-ion production, fission and production of heavy residues. Recent results are presented and future program of development is outlined.

  3. Neutron scattering studies of bio-polymer-water systems: solvent mobility and collective excitations

    Energy Technology Data Exchange (ETDEWEB)

    Middendorf, H.D. [Oxford Univ. (United Kingdom). Clarendon Lab.

    1995-12-31

    The understanding of bio-polymer-water interactions at the molecular level depends crucially on a good characterization of dissipative processes and on accurate model parameters derived from experiments. The fundamental interest of this study is the coupling between hard and soft degrees of freedom, the dynamics of hydrogen-bonded molecular components and the effect of hydration on collective modes. The experiments and results discussed in this paper demonstrate how neutron scattering provides new insights into the dynamics of hydrated biomolecules. The ability to do diffraction-cum-spectroscopy over a large Q,{omega}-range corresponding to the space and time scales of bio-polymer-water interactions opens new ways which can be exploited for testing and refining theoretical models and simulations. Outstanding assets of neutron techniques in this context are the capability to probe diffusive as well as cooperative processes over scale lengths from about 1 to a few angstroms, together with the possibility of varying scattering contrast between the constituents of a heterogeneous system. Two systems are considered: a globular, slightly hydrated protein (phycocyanin) and a highly hydrated network of polysaccharide fibers. The phycocyanin results draw attention to the fact that the energy landscape of a hydrated biomolecule is very complex. Some of the concepts and models used in theoretical work will need to be refined substantially in order to accommodate data from experimental techniques capable of providing genuine spatio-temporal information. The characterization of hydration phenomena by two or three discrete relaxation times is too simplistic and the two-state models are inadequate to describe protein hydration. (J.S.). 39 refs., 10 figs.

  4. Neutron scattering studies of bio-polymer-water systems: solvent mobility and collective excitations

    International Nuclear Information System (INIS)

    The understanding of bio-polymer-water interactions at the molecular level depends crucially on a good characterization of dissipative processes and on accurate model parameters derived from experiments. The fundamental interest of this study is the coupling between hard and soft degrees of freedom, the dynamics of hydrogen-bonded molecular components and the effect of hydration on collective modes. The experiments and results discussed in this paper demonstrate how neutron scattering provides new insights into the dynamics of hydrated biomolecules. The ability to do diffraction-cum-spectroscopy over a large Q,ω-range corresponding to the space and time scales of bio-polymer-water interactions opens new ways which can be exploited for testing and refining theoretical models and simulations. Outstanding assets of neutron techniques in this context are the capability to probe diffusive as well as cooperative processes over scale lengths from about 1 to a few angstroms, together with the possibility of varying scattering contrast between the constituents of a heterogeneous system. Two systems are considered: a globular, slightly hydrated protein (phycocyanin) and a highly hydrated network of polysaccharide fibers. The phycocyanin results draw attention to the fact that the energy landscape of a hydrated biomolecule is very complex. Some of the concepts and models used in theoretical work will need to be refined substantially in order to accommodate data from experimental techniques capable of providing genuine spatio-temporal information. The characterization of hydration phenomena by two or three discrete relaxation times is too simplistic and the two-state models are inadequate to describe protein hydration. (J.S.). 39 refs., 10 figs

  5. The data acquisition system of the neutron time-of-flight facility nTOF at CERN

    CERN Document Server

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

    2005-01-01

    The n_TOF facility at CERN has been designed for the measurement of neutron capture, fission and (n, multiplied by n) cross-sections with high accuracy. This requires a flexible and - due to the high instantaneous neutron flux - almost dead time free data acquisition system. A scalable and versatile data solution has been designed based on 8-bit flash-ADCs with sampling rates up to 2 GHz and 8 Mbyte memory buffer. The software is written in C and C++ and is running on PCs equipped with RedHat Linux.

  6. Analysis and databasing software for integrated tomographic gamma scanner (TGS) and passive-active neutron (PAN) assay systems

    International Nuclear Information System (INIS)

    The CTEN-FIT program, written for Windows 9x/NT in C++,performs databasing and analysis of combined thermal/epithermal neutron (CTEN) passive and active neutron assay data and integrates that with isotopics results and gamma-ray data from methods such as tomographic gamma scanning (TGS). The binary database is reflected in a companion Excel database that allows extensive customization via Visual Basic for Applications macros. Automated analysis options make the analysis of the data transparent to the assay system operator. Various record browsers and information displays simplify record keeping tasks

  7. Development of an ultra-high-speed scanning neutron tomography system for high-quality and four-dimensional visualizations

    International Nuclear Information System (INIS)

    A new neutron tomography imaging system was developed in order to realize high-quality three-dimensional (3D) and four-dimensional (4D) visualizations by fusing the high-frame-rate neutron radiography and computed tomography (CT) techniques. The fundamental idea is that the object is revolved with high rotating speed and the neutron radiography images are recorded with a high-speed video camera and an image intensifier, and then the consecutive images are processed by a 3D CT technique. The 4D dynamic images of the sand flow in the sandglasses could be visualized clearly. This new technique has also an advantage in that it can reduce radio-activation of the object materials remarkably.

  8. Systems and methods for neutron detection using scintillator nano-materials

    Science.gov (United States)

    Letant, Sonia Edith; Wang, Tzu-Fang

    2016-03-08

    In one embodiment, a neutron detector includes a three dimensional matrix, having nanocomposite materials and a substantially transparent film material for suspending the nanocomposite materials, a detector coupled to the three dimensional matrix adapted for detecting a change in the nanocomposite materials, and an analyzer coupled to the detector adapted for analyzing the change detected by the detector. In another embodiment, a method for detecting neutrons includes receiving radiation from a source, converting neutrons in the radiation into alpha particles using converter material, converting the alpha particles into photons using quantum dot emitters, detecting the photons, and analyzing the photons to determine neutrons in the radiation.

  9. Laser Inertial Fusion-based Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    OpenAIRE

    Kramer, Kevin James

    2010-01-01

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by ...

  10. Design of a γ-ray analysis system for determination of boron in a patient's head, during neutron irradiation

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) is a new radiation therapy in which thermal neutron capture by 10B is used for the selective destruction of a cancer tumour. At the High Flux Reactor (HFR) in Petten, Netherlands, a therapy facility is built for the neutron irradiations. In first instance, patients with a brain tumour will be treated. The doses delivered to the tumour and to the healthy tissue depend on the thermal neutron fluence and on the boron concentrations in these regions. Yet, both concentrations change in time after the administration of the tumour-seeking boron compound. An accurate determination of the patient's dose requires the knowledge of these time dependent concentrations during the therapy. For this reason, a γ-ray telescope system, together with a reconstruction tool, are developed. Two HPGe-detectors measure the 478 keV prompt γ-rays which are emitted at the boron neutron capture reaction, in a large background of γ-rays and neutrons. By using the detectors in a telescope configuration, only γ-rays emitted by a small specific region are detected. The best shielding of the detectors is obtained by performing the measurements through a small hole in the iron roof. A reconstruction tool is developed to calculate absolute boron concentrations using the measured boron γ-ray detection rates. Besides the boron γ-rays, a large component of 2.2 MeV γ-rays emitted at thermal neutron capture in hydrogen is measured. Since the hydrogen distribution is almost homogeneous over the head, this component can serve as a measure of the total number of thermal neutrons in the observed volume. By using the hydrogen γ-line for normalisation of the boron concentration, the reconstruction tool eliminates the greater part of the influence of the inhomogeneity of the thermal neutron distribution. MCNP calculations are used as a tool for the optimisation of the detector configuration. Experiments on a head phantom with 5 ppm 10B in healthy tissue and 62 ppm in

  11. A D-D/D-T fusion reaction based neutron generator system for liver tumor BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Koivunoro, H.; Lou, T.P.; Leung, K. N.; Reijonen, J.

    2003-04-02

    Boron-neutron capture therapy (BNCT) is an experimental radiation treatment modality used for highly malignant tumor treatments. Prior to irradiation with low energetic neutrons, a 10B compound is located selectively in the tumor cells. The effect of the treatment is based on the high LET radiation released in the {sup 10}B(n,{alpha}){sup 7}Li reaction with thermal neutrons. BNCT has been used experimentally for brain tumor and melanoma treatments. Lately applications of other severe tumor type treatments have been introduced. Results have shown that liver tumors can also be treated by BNCT. At Lawrence Berkeley National Laboratory, various compact neutron generators based on D-D or D-T fusion reactions are being developed. The earlier theoretical studies of the D-D or D-T fusion reaction based neutron generators have shown that the optimal moderator and reflector configuration for brain tumor BNCT can be created. In this work, the applicability of 2.5 MeV neutrons for liver tumor BNCT application was studied. The optimal neutron energy for external liver treatments is not known. Neutron beams of different energies (1eV < E < 100 keV) were simulated and the dose distribution in the liver was calculated with the MCNP simulation code. In order to obtain the optimal neutron energy spectrum with the D-D neutrons, various moderator designs were performed using MCNP simulations. In this article the neutron spectrum and the optimized beam shaping assembly for liver tumor treatments is presented.

  12. Neutronic Studies in Support of Accelerator-Driven Systems: The MUSE Experiments in the MASURCA Facility

    International Nuclear Information System (INIS)

    The MUSE program (multiplication with an external source) is in progress at the MASURCA critical facility at the Cadarache Research Center of the Commissariat a l'Energie Atomique in France. The program is dedicated to the physics studies of accelerator-driven systems in support of transmutation studies of minor actinides and long-lived fission products. It began in 1995 with the coupling of a Cf source in MASURCA and was followed by a commercial (d,T) source. In 2001, a specially constructed (d,D)/(d,T) neutron generator (GENEPI) was placed in MASURCA and the MUSE-4 program commenced.We describe the first phases of the MUSE-4 program, with data presented that were obtained up to about the summer of 2002. We present some results from the 'reference' configuration, which can operate at critical. We present traverses of measured fission reaction rates, with comparison to calculations. Also in the reference configuration, we performed activation foil measurements and present these results compared to calculations.Because a major objective of the MUSE program is to test and qualify methods of subcritical reactivity measurement, we have devoted a major portion of our studies to this area. We have used classical methods (rod drop, source multiplication) to attempt to measure the subcritical level. In these early phases we studied core configurations of around keff = 0.995. Deeper subcriticality (keff = 0.96) was achieved by inserting a safety rod.In addition to the methods mentioned above, we have devoted a lot of effort to pulse neutron source, fluctuation (Rossi-α and Feynman-α), and transfer function methods (e.g., cross-power spectral density). We present our preliminary results of all the methods, with some discussion regarding cross comparison

  13. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, R.E.

    1996-09-30

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution`s concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the `Poisoned Tube Tank` because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service.

  14. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    International Nuclear Information System (INIS)

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution's concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the 'Poisoned Tube Tank' because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service

  15. Control system for the Spallation Neutron Source H- source test facility Allison scanner

    International Nuclear Information System (INIS)

    Spallation Neutron Source is currently in progress of a multiyear plan to ramp ion beam power to the initial design power of 1.4 MW. Key to reaching this goal is understanding and improving the operation of the H- ion source. An Allison scanner was installed on the ion source in the test facility to support this improvement. This paper will discuss the hardware and the software control system of the installed Allison scanner. The hardware for the system consists of several parts. The heart of the system is the scanner head, complete with associated bias plates, slits, and signal detector. There are two analog controlled high voltage power supplies to bias the plates in the head, and a motor with associated controller to position the head in the beam. A multifunction data acquisition card reads the signals from the signal detector, as well as supplies the analog voltage control for the power supplies. To synchronize data acquisition with the source, the same timing signal that is used to trigger the source itself is used to trigger data acquisition. Finally, there is an industrial personal computer to control the rest of the hardware. Control software was developed using National Instruments LABVIEW, and consists of two parts: a data acquisition program to control the hardware and a stand alone application for offline user data analysis.

  16. Response of EBR-II's delayed neutron monitoring systems during sinusoidal reactivity-oscillation experiments

    International Nuclear Information System (INIS)

    Multifrequency reactivity-oscillation experiments were recently performed during operation with an exposed fission source in Experimental Breeder Reactor II (EBR-II). The purpose of these experiments was to evaluate the response characteristics of EBR-II's delayed neutron (DN) monitoring systems under a broad range of transient power and transient temperature conditions. A secondary objective was to verify that EBR-II's fission product source (FPS) capsules, which are being supplied to foreign reactors for calibration of their fission product monitoring systems, are pure recoil sources - i.e., that the fission product release rate is directly proportional to the product of the fission rate and surface area under both steady-state and transient temperature conditions. A detailed analysis of the results from these experiments has demonstrated that (a) EBR-II's DN monitoring systems are very sensitive and have excellent counting statistics; (b) they are highly linear with respect to power variations and are unaffected by concomitant variations in DND temperature; and (c) they can accurately follow transient release rate variations over a broad frequency range

  17. Plutonium waste crib logging using the prompt fission neutron uranium logging system

    International Nuclear Information System (INIS)

    Sandia Laboratories' Uranium Logging Project has demonstrated their prompt fission neutron (PFN) logging system at the Hanford, WA, site for Rockwell-Hanford Operations (RHO). The dates of the demonstration were July 31 through August 2, 1979. The purpose was to show RHO the capabilities of the system for measuring plutonium concentration. An underground effluent disposal crib associated with their processing facilities was used as the test site. The performance criterion was to be able to detect a 10 nCi/g concentration of plutonium. Six test wells penetrating the crib were logged, as were three other wells. The PFN tool was able to maintain a good signal-to-noise ratio even under the most extreme conditions of high count rate and high background. The wells at the center of the crib indicated very high concentrations of plutonium, while those at the periphery indicated much less. Concentrations estimated to be lower than 10 nCi/g were detected. Comparisons with core data were not made. The technique used to obtain physical samples for analysis did not follow uranium-exploration coring practice so comparisons were not possible. The data interpretation model used was originally developed for uranium and was modified to calculate plutonium concentration. Results indicated that the operation of a PFN logging system by RHO personnel would provide a suitable technique for monitoring transuranic waste storage sites

  18. Recent advances in neutron tomography

    International Nuclear Information System (INIS)

    Neutron imaging has been shown to be an excellent imaging tool for many nondestructive evaluation applications. Significantly improved contrast over X-ray images is possible for materials commonly found in engineering assemblies. The major limitations have been the neutron source and detection. A low cost, position sensitive neutron tomography detector system has been designed and built based on an electro-optical detector system using a LiF-ZnS scintillator screen and a cooled charge coupled device. This detector system can be used for neutron radiography as well as two and three-dimensional neutron tomography. Calculated performance of the system predicted near-quantum efficiency for position sensitive neutron detection. Experimental data was recently taken using this system at McClellan Air Force Base, Air Logistics Center, Sacramento, CA. With increased availability of low cost neutron sources and advanced image processing, neutron tomography will become an increasingly important nondestructive imaging method

  19. The future underwater Neutron Imaging System of the Jules Horowitz MTR: An equipment improving the scientific quality of irradiation programs

    International Nuclear Information System (INIS)

    Standard NDE techniques used in support to the irradiation process on fuels and materials in a Material Test Reactor (MTR) comprise i) photonic imaging: gamma scanning and gamma tomography, X-ray imaging and X-ray tomography, and ii) neutron imaging: neutron radiography. Due to different interactions of photons and neutrons with matter, these examinations means are not sensitive to the same chemical elements or isotopes and consequently don't reveal the same details and don't provide the same information. Two identical underwater photonic imaging benches, coupling gamma scanning and X-tomography, will be installed respectively in the reactor pool and in the storage pool of the JHR, capable of welcoming and checking an irradiation device containing the experimental sample. An underwater neutron imaging bench will be also implanted in the reactor pool and will gamma-X tomography bench in hot cell in air will check samples after dismounting from the sample holder. As a complement of a previous paper more focussed on photonic imaging benches and presented at the IGORR 13 conference, this paper presents in details the Neutron Imaging System (NIS) of the JHR. After a reviewing of the scientific information for nuclear fuel programs specifically gained thanks to this bench, the scientific needs in the fuel domain will be developed (sample geometries, specification of performances...). After that, the characteristics and the integration issues of the system in the reactor pool will be detailed. A focus will be carried out on the design of a performing detection system. Simulation of images obtained on objects reproducing real sample configurations will be shown. Finally, other aspects linked to the bench operation and planning will conclude the paper

  20. An autocorrelation method to detect periodic gravitational waves from neutron stars in binary systems

    Science.gov (United States)

    Viceré, Andrea; Yvert, Michel

    2016-08-01

    Rotating, non-axisymmetric neutron stars are expected to emit continuous gravitational waves at a nearly stable frequency. Nowadays about 2500 pulsars have been detected, thanks to their beamed electromagnetic emission, and many more of these objects should exist, whose electromagnetic beam does not include Earth and cannot be detected. The gravitational emission is not beamed, and could be accessible to gravitational observatories, even though no detection as been claimed yet. About half of the pulsars predicted to possibly emit gravitational waves in the frequency range accessible to ground-based interferometers belongs to binary systems; this is an additional complication, because the frequencies of these pulsars are Doppler-shifted due to their orbital motion, and an optimal detection strategy would require a computing power far beyond the present capabilities. We present here an approach which allows searching all-sky for such sources, over a broad range of frequencies, orbital periods and binary system eccentricities, reaching sensitivities potentially good enough to provide candidates for more sophisticated hierarchical detection methods. We test this new technique using real data taken during the first science run of Virgo, and estimating the sensitivity to a set of simulated pulsar signals.

  1. Development of response transforms from comparative study of commercial pulsed neutron capture logging systems

    International Nuclear Information System (INIS)

    The absence of a common calibration facility to ascertain the accuracy of commercial pulsed neutron capture logging systems, coupled with the desire for more accurate saturation determination from time-lapse logs, prompted Saudi Aramco to carry out this paper. Three generations of Schlumberger's Thermal Decay Time (TDT) logging devices, viz., TDT-K, TDT-M, and TDT-P along with Atlas Wireline PDK-100 system were run in an Aramco well. The wellbore - 8-1/2 inch with 7-inch casting - penetrated clean sand, shaly sand, and shale streaks sequence as exhibited by the open hole natural gamma ray log. Initially, the well bore fluid was diesel. The fluid was then changed to brines of 42-kppm and 176-kppm NaCl, respectively. Three repeat passes at a logging speed of 900 ft/hr were obtained by each device for each of the three borehole liquids. In the case of PDK-100, a second set of log runs was obtained at 1800 ft/hr

  2. Neutron drops radii probed by the neutron skin thickness of nuclei

    OpenAIRE

    Zhao, P. W.; Gandolfi, S

    2016-01-01

    Multi-neutron systems are crucial to understand the physics of neutron-rich nuclei and neutron stars. Neutron drops, neutrons confined in an external field, are investigated systematically in both non-relativistic and relativistic density functional theories and with ab initio calculations. We demonstrate a strong linear correlation, which is universal in the realm of mean-field models, between the root-mean-square (rms) radii of neutron drops and the neutron skin thickness of Pb-208 and Ca-4...

  3. Development and characterization of two-component albedo based neutron individual monitoring system using thermoluminescent detectors; Desenvolvimento e caracterizacao de um sistema de monitoracao individual de neutrons tipo albedo de duas componentes usando detectores termoluminescentes

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Marcelo Marques

    2008-07-01

    A TLD-albedo based two-component neutron individual monitoring system was developed and characterized in this work. The monitor consists of a black plastic holder, an incident neutron boron loaded shield, a moderator polyethylene body (to increase its response), two pairs of TLD-600 and TLD-700 (one pair to each component) and an adjustable belt. This monitoring system was calibrated in thermal neutron fields and in 70 keV, 144 keV, 565 keV, 1.2 MeV and 5 MeV monoenergetic neutron fields. In addition, it was calibrated in {sup 252C}f(D{sub 2}O), {sup 252}Cf, {sup 241}Am-B, {sup 241}Am-Be and {sup 238}Pu-Be source fields. For the latter, the lower detection levels are, respectively, 0.009 mSv, 0.06 mSv, 0.12 mSv, 0.09 mSv and 0.08 mSv. The participation in an international intercomparison sponsored by IAEA with simulated workplace fields validated the system. The monitoring system was successfully characterized in the ISO 21909 standard and in an IRD - the Brazilian Institute for Radioprotection and Dosimetry - technical regulation draft. Nowadays, the neutron individual system is in use by IRD for whole body individual monitoring of five institutions, which comprehend several activities. (author)

  4. Role of neutron and proton system in spin cut off parameter and entropy of {sup 89,90}Y

    Energy Technology Data Exchange (ETDEWEB)

    Rahmatinejad, A. [Department of Physics, Faculty of Science, University of Zanjan, Zanjan (Iran, Islamic Republic of); Razavi, R., E-mail: rrazavin@ihu.ac.ir [Physics Department, Faculty of Science, Imam Hossein Comprehensive University, Tehran (Iran, Islamic Republic of); Kakavand, T. [Department of Physics, Faculty of Science, Imam Khomeini International University, Qazvin (Iran, Islamic Republic of)

    2015-09-15

    The nuclear level densities, entropies and spin cut off parameters have been determined in {sup 89,90}Y nuclei using the BCS model with inclusion of pairing interaction. The results have a good agreement with the recent experimental data on the level densities measured by the Oslo group. In addition, the entropy excess of {sup 90}Y compared to {sup 89}Y as a function of temperature has been extracted. Also, the role of neutron and proton systems in the entropy excess as well as the spin cut off excess have been investigated using the entropy excess ratio and spin cut off excess ratio introduced in our previous publication. The role of the neutron system at low temperatures, the temperatures below critical temperature, in the semi-magic nucleus {sup 89}Y is similar compared to the closed shell proton system in the tin isotopes.

  5. Role of neutron and proton system in spin cut off parameter and entropy of 89,90Y

    Science.gov (United States)

    Rahmatinejad, A.; Razavi, R.; Kakavand, T.

    2015-09-01

    The nuclear level densities, entropies and spin cut off parameters have been determined in 89,90Y nuclei using the BCS model with inclusion of pairing interaction. The results have a good agreement with the recent experimental data on the level densities measured by the Oslo group. In addition, the entropy excess of 90Y compared to 89Y as a function of temperature has been extracted. Also, the role of neutron and proton systems in the entropy excess as well as the spin cut off excess have been investigated using the entropy excess ratio and spin cut off excess ratio introduced in our previous publication. The role of the neutron system at low temperatures, the temperatures below critical temperature, in the semi-magic nucleus 89Y is similar compared to the closed shell proton system in the tin isotopes.

  6. Polysiloxane based neutron detectors

    OpenAIRE

    Dalla Palma, Matteo

    2016-01-01

    In the last decade, neutron detection has been attracting the attention of the scientific community for different reasons. On one side, the increase in the price of 3He, employed in the most efficient and the most widely used neutron detectors. On the other side, the harmfulness of traditional xylene based liquid scintillators, used in extremely large volumes for the detection of fast neutrons. Finally, the demand for most compact and rough systems pushed by the increased popularity of neutro...

  7. Simulation Research on Neutron Guide System CNGC for China Advanced Research Reactor

    Institute of Scientific and Technical Information of China (English)

    WEI; Guo-hai; HAN; Song-bai; HE; Lin-feng; WANG; Yu; WANG; Hong-li; LIU; Yun-tao; CHEN; Dong-feng; ZHAO; Zhi-xiang

    2012-01-01

    <正>The out-pile section of the neutron guide CNGC at CARR (China Advanced Research Reactor) was designed by Monte Carlo simulation with VITESS. The out-pile section of CNGC will be spitted to CNGC-S and CNGC-N, the cold neutron imaging facility and small angle neutron scattering facility will be installed at the end of guides respectively. XRD patterns of Bi1-xLaxFe1-yScyO3 were shown in Fig. 1.

  8. Los Alamos second-generation system for passive and active neutron assays of drum-size containers

    International Nuclear Information System (INIS)

    We describe in a comprehensive fashion the Los Alamos second-generation system for passive and active neutron assays of drum-size containers. The developmental history of this 7-year project is presented with emphasis on the pulsed active neutron technique (differential dieaway), which has achieved milligram levels of assay sensitivity for both plutonium and uranium wastes. We describe in detail the matrix effects for both passive and active neutron assays. We present in a thorough fashion our novel approach to achieving comprehensive corrections for these matrix effects using measurements made during the assays. We develop a matrix correction formalism based on separate neutron absorption and moderator indices determined from these measurements. These are presented as a series of analytic functions fitted to the data. Absolute calibrations and calibration standards are discussed, as is a practical means (pink drum measurements) of achieving routine calibration verification at all implementation sites. We present our overall assay algorithm, integrating absolute calibrations with matrix corrections. We also present a systematic error formalism that is based on the matrix response data. Finally, we outline a strategy for the verification of our entire assay formalism. This is based on measurements with a set of salted waste matrix drums combined with systematic assay intercomparisons of well-characterized transuranic wastes

  9. Standard specification for boron-Based neutron absorbing material systems for use in nuclear spent fuel storage racks

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This specification defines criteria for boron-based neutron absorbing material systems used in racks in a pool environment for storage of nuclear light water reactor (LWR) spent-fuel assemblies or disassembled components to maintain sub-criticality in the storage rack system. 1.2 Boron-based neutron absorbing material systems normally consist of metallic boron or a chemical compound containing boron (for example, boron carbide, B4C) supported by a matrix of aluminum, steel, or other materials. 1.3 In a boron-based absorber, neutron absorption occurs primarily by the boron-10 isotope that is present in natural boron to the extent of 18.3 ± 0.2 % by weight (depending upon the geological origin of the boron). Boron, enriched in boron-10 could also be used. 1.4 The materials systems described herein shall be functional – that is always be capable to maintain a B10 areal density such that subcriticality Keff <0.95 or Keff <0.98 or Keff < 1.0 depending on the design specification for the service...

  10. Neutron scattering for investigation into the connection between phonons and diffusion in metallic systems

    International Nuclear Information System (INIS)

    For examining the connection between the diffusion systematics and the lattice dynamics of the body-centered cubic metals, the temperature dependence of the self-diffusion (radiotracer technique) and the phonon dispersion (neutron scattering) have been measured in selected systems. In continuation of previous studies, the goal of the examinations reported was to put the earlier developed phonon-related diffusion model on a broader experimental basis, in order to perform verifying analyses. The phonon dispersion of the group 5 metal Nb has been measured up to high temperatures. In contrast to the values measured for the group 4 (β-Zr) and group 6 (Cr) metals, the dispersion in Nb revealed an only very weak temperature dependence. The exceptional case of the bcc β-Tl has been examined by measuring the diffusion and the dispersion in the β-T83In17 alloy. Significant deviations from the conditions in the bcc transition metals have been found. Self-diffusion has been measured for the first time in Ba and β-Sc. Their diffusion systematics correlate with electron configuration. The influence of the d-electron concentration on the diffusion systematics has been measured in Ti-Mo and Hf-Nb alloys, the results backing the predictions of the phonon-related diffusion model. (orig.)

  11. Quasielastic neutron scattering study of large amplitude motions in molecular systems

    Energy Technology Data Exchange (ETDEWEB)

    Bee, M. [Univ. J. Fourier - Grenoble 1, Lab. de Spectrometrie Physique, Saint-Martin d`Heres (France)

    1996-12-31

    This lecture aims at giving some illustrations of the use of Incoherent Quasielastic Neutron Scattering in the investigation of motions of atoms or molecules in phases with dynamical disorder. The general incoherent scattering function is first recalled. Then the Elastic Incoherent Structure Factor is introduced. It is shown how its determination permits to deduce a particular dynamical model. Long-range translational diffusion is illustrated by some experiments carried out with liquids or with different chemical species intercalated in porous media. Examples of rotational motions are provided by solid phases where an orientational disorder of the molecules exists. The jump model is the most commonly used and yields simple scattering laws which can be easily handled. Highly disordered crystals require a description in terms of the isotropic rotational diffusion model. Many of the present studies are concerned with rather complicated systems. Considerable help is obtained either by using selectively deuterated samples or by carrying out measurements with semi-oriented samples. (author) 5 figs., 14 refs.

  12. Determination of zinc concentration in female reproductive system by instrumental neutron activation

    International Nuclear Information System (INIS)

    Non-surgical female sterilization through the transcervical insertion of quinacrine pellets was considered a definitive, low-cost, safe and effective contraceptive method. The zinc, present in both uterus and Fallopian tubes, inhibit the quinacrine efficiency. The addition of copper increases the efficacy of quinacrine, reducing the risk of pregnancy due to the failure to obstruct the Fallopian tubes. The copper neutralized the deleterious effect of the zinc and so the treatment efficacy is increased. In order to obtain a mapping to study the zinc content in the female reproductive system, samples of both uterus and Fallopian tubes were analyzed by instrumental neutron activation. The results show that, on average, the obtained zinc concentrations in tubes (89 μg-g-1) is lower than in the uterus (118 μg-g-1), confirming results obtained by other authors. These results will support a research project about non-surgical female sterilization of the 'Faculdade de Medicina da Universidade Federal de Minas Gerais' (Medical School of Federal University of Minas Gerais). The used methodology and obtained results are here reported. (author)

  13. Neutronic / thermal-hydraulic coupling with the code system Trace / Parcs

    International Nuclear Information System (INIS)

    The developed models for Parcs and Trace codes corresponding for the cycle 15 of the Unit 1 of the Laguna Verde nuclear power plant are described. The first focused to the neutronic simulation and the second to thermal hydraulics. The model developed for Parcs consists of a core of 444 fuel assemblies wrapped in a radial reflective layer and two layers, a superior and another inferior, of axial reflector. The core consists of 27 total axial planes. The model for Trace includes the vessel and its internal components as well as various safety systems. The coupling between the two codes is through two maps that allow its intercommunication. Both codes are used in coupled form performing a dynamic simulation that allows obtaining acceptably a stable state from which is carried out the closure of all the main steam isolation valves (MSIVs) followed by the performance of safety relief valves (SRVs) and ECCS. The results for the power and reactivities introduced by the moderator density, the fuel temperature and total temperature are shown. Data are also provided like: the behavior of the pressure in the steam dome, the water level in the downcomer, the flow through the MSIVs and SRVs. The results are explained for the power, the pressure in the steam dome and the water level in the downcomer which show agreement with the actions of the MSIVs, SRVs and ECCS. (Author)

  14. Determination of zinc concentration in female reproductive system by instrumental neutron activation

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Fernando Ramos de, E-mail: framosc@oi.com.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Oliveira, Arno Heeren de, E-mail: heeren@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Medicina. Dept. de Ginecologia e Obstetricia; Ferreira, Claudia R.C.; Ferreira, Ricardo Alberto Neto; Menezes, Maria Angela de B.C., E-mail: claudia@medicina.ufmg.b, E-mail: ranf@cdtn.b, E-mail: menezes@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2009-07-01

    Non-surgical female sterilization through the transcervical insertion of quinacrine pellets was considered a definitive, low-cost, safe and effective contraceptive method. The zinc, present in both uterus and Fallopian tubes, inhibit the quinacrine efficiency. The addition of copper increases the efficacy of quinacrine, reducing the risk of pregnancy due to the failure to obstruct the Fallopian tubes. The copper neutralized the deleterious effect of the zinc and so the treatment efficacy is increased. In order to obtain a mapping to study the zinc content in the female reproductive system, samples of both uterus and Fallopian tubes were analyzed by instrumental neutron activation. The results show that, on average, the obtained zinc concentrations in tubes (89 mug-g{sup -1}) is lower than in the uterus (118 mug-g{sup -1}), confirming results obtained by other authors. These results will support a research project about non-surgical female sterilization of the 'Faculdade de Medicina da Universidade Federal de Minas Gerais' (Medical School of Federal University of Minas Gerais). The used methodology and obtained results are here reported. (author)

  15. Neutron Monitoring Systems for the Characterisation of Nuclear Fuel and Waste - Methodology and Applications - 12055

    International Nuclear Information System (INIS)

    The most characteristic behaviour of nuclear fuel or waste contaminated by fission material or isotopes resulting from fissile processes is the emission of neutrons. At the same time because of the high penetration of the material by neutrons, they are an ideal probe for measurement by non-destructive assay. The detection and data analysis in this case is quite different compared to methods using gamma measuring techniques. Neutron detection monitors have been in routine operation for a long time, showing their excellent detection capabilities. The neutron monitors designed for different applications have demonstrated their capabilities during daily operation in the field of burned up fuel elements and for nuclear waste with alpha activity. Lately the data analysis was refined and the quality of the results was improved by using MCNP calculations. Last but not least the layout and the calibration of neutron monitors are nowadays unfeasible without support by MCNP simulations. In the field of non-destructive assay the neutron monitors are undisputed. (authors)

  16. A Fusion Neutron Source Driven Sub-Critical Nuclear Energy System: A Way for Early Application of Fusion Technology

    Institute of Scientific and Technical Information of China (English)

    吴宜灿

    2001-01-01

    This paper proposes a sub-critical nuclear energy system driven by fusion neutron source, FDS, which can be used to transmute long-lived radioactive wastes and to produce fissile nuclear fuel as a way for early application of fusion technology. The necessity and feasibility to develop that system in China are illustrated on the basis of prediction of the demand of energy source in the first half of the 21th century, the status of current fission energy supply and the progress in fusion technology in the vorld. The characteristics of fusion neutron driver and the potential for transmutation of long-lived nuclear wastes and breeding of fissile nuclear fuel in a blanket are analyzed. A scenario of development steps is proposed.``

  17. Reshaping of computational system for dosimetry in neutron and photons radiotherapy based in stochastic methods - SISCODES

    International Nuclear Information System (INIS)

    This work shows the remodeling of the Computer System for Dosimetry of Neutrons and Photons in Radiotherapy Based on Stochastic Methods . SISCODES. The initial description and status, the alterations and expansions (proposed and concluded), and the latest system development status are shown. The SISCODES is a system that allows the execution of a 3D computational planning in radiation therapy, based on MCNP5 nuclear particle transport code. The SISCODES provides tools to build a patient's voxels model, to define a treatment planning, to simulate this planning, and to view the results of the simulation. The SISCODES implements a database of tissues, sources and nuclear data and an interface to access then. The graphical SISCODES modules were rewritten or were implemented using C++ language and GTKmm library. Studies about dose deviations were performed simulating a homogeneous water phantom as analogue of the human body in radiotherapy planning and a heterogeneous voxel phantom, pointing out possible dose miscalculations. The Soft-RT and PROPLAN computer codes that do interface with SISCODES are described. A set of voxels models created on the SISCODES are presented with its respective sizes and resolutions. To demonstrate the use of SISCODES, examples of radiation therapy and dosimetry simulations for prostate and heart are shown. Three protocols were simulated on the heart voxel model: Sm-153 filled balloon and P-32 stent, to prevent angioplasty restenosis; and Tl-201 myocardial perfusion, to imaging. Teletherapy with 6MV and 15MV beams were simulated to the prostate, and brachytherapy with I-125 seeds. The results of these simulations are shown on isodose curves and on dose-volume histograms. The SISCODES shows to be a useful tool for research of new radiation therapy treatments and, in future, can also be useful in medical practice. At the end, future improvements are proposed. I hope this work can contribute to develop more effective radiation therapy

  18. Remodeling and Characterization of Pneumatic Transfer System (PTS no.3) of HANARO Research Reactor for Neutron Activation Analysis

    International Nuclear Information System (INIS)

    A pneumatic transfer system (PTS) is one of the facilities to be used in an irradiation of a target material for an instrumental neutron activation analysis (INAA) in a research reactor. This technical report describes for the irradiation test and the characteristics and removing, remodelling of the reinstalled PTS no.3 in NAA no.3 irradiation hole at HANARO for user information and the reactor management

  19. Small angle neutron scattering study of U(VI) third phase formation in HNO3/DHDECMP–-dodecane system

    Indian Academy of Sciences (India)

    K V Lohithakshan; V K Aswal; S K Aggarwal

    2008-11-01

    Small angle neutron scattering studies (SANS) were carried out to understand the formation of third phase in DHDECMP–dodecane–UO2(NO3)2/HNO3 system. It was observed that third phase formation takes place due to the formation of UO2(NO3)2. DHDECMP reverse micelles in the dodecane phase. SANS data obtained were interpreted with particle interaction model using Baxter sticky spheres model.

  20. Benchmarking of the WIMSD/CITATION deterministic code system for the neutronic calculations of TRIGA Mark-III research reactors

    International Nuclear Information System (INIS)

    Highlights: • Benchmark study performed for the neutronic calculations of TRIGA research reactors. • WIMSD-5B/CITATION is the utilized code system along with the WIMSD-IAEA-69 library. • The studied condensed spectra are five and seven energy groups spectra. • Analyzed: lattice parameters, reactivities, CR worth, flux and power distribution. • The lattice and neutronic parameters showed the accuracy of both condensed spectra. - Abstract: The objective of this paper is to assess the suitability and accuracy of the deterministic diffusion method for the neutronic calculations of the TRIGA Mark-III research reactors using the WIMSD/CITATION code system in proposed condensed energy spectra of five and seven energy groups with one and three thermal groups respectively. The utilized cell transport calculations code and core diffusion calculations code are the WIMSD-5B and the CITVAP v3.1 codes respectively, along with the WIMSD-IAEA-69 nuclear data library. Firstly, the assessment goes through analyzing the integral parameters – keff, ρ238, δ235, δ238, and C* – of the TRX and BAPL benchmark lattices and comparison with experimental and previous reference results using other ENDLs at the full energy spectra which show good agreement with the references at both spectra. Secondly, evaluation of the 3D nuclear characteristics of three different cores of the TRR-1/M1 TRIGA Mark-III Thai research reactor at the condensed energy spectra. The results include the excess reactivities of the cores and the worth of selected control rods which were compared with reference Monte Carlo results and experimental values. The results show good agreement with the references at both energy spectra and the better accuracy are attainable in the five energy groups spectrum. The results also include neutron flux distributions which are evaluated for future comparisons with other calculational techniques even they are comparable to reactors and fuels of the same type. The

  1. Experimental study on neutronics in bombardment of thick targets by high energy proton beams for accelerator-driven sub-critical system

    International Nuclear Information System (INIS)

    The experimental study on neutronics in the target region of accelerator-driven sub-critical system is carried out by using the high energy accelerator in Joint Institute for Nuclear Research, Dubna, Russia. The experiments with targets U(Pb), Pb and Hg bombarded by 0.533, 1.0, 3.7 and 7.4 GeV proton beams show that the neutron yield ratio of U(Pb) to Hg and Pb to Hg targets is (2.10 +- 0.10) and (1.76 +- 0.33), respectively. Hg target is disadvantageous to U(Pb) and Pb targets to get more neutrons. Neutron yield drops along 20 cm thick targets as the thickness penetrated by protons increases. The lower the energy of protons, the steeper the neutron yield drops. In order to get more uniform field of neutrons in the targets, the energy of protons from accelerators should not be lower than 1 GeV. The spectra of secondary neutrons produced by different energies of protons are similar, but the proportion of neutrons with higher energy gradually increases as the proton energy increases

  2. 小型中子源高能中子照相装置准直屏蔽系统设计%Conception Design of Shielding Collimator System for High Energy Neutron Radiography with Minitype Neutron Source

    Institute of Scientific and Technical Information of China (English)

    吴洋; 窦海峰; 唐彬; 霍合勇

    2013-01-01

    Shielding collimator system is necessary in the neutron radiography installation; this issue gives the conception design of shielding collimator system for FNR about high energy neutron source by MCNP.Preliminarily ascertain the material component and dimension,confirm the neutron flux at imaging position,imaging distance,imaging field range of the FNP installation in theory.%准直屏蔽系统是中子照相装置的必要设备.本文采用蒙特卡洛中子输运程序(MCNP)等软件对高能中子准直屏蔽系统进行理论设计,初步确定了其材料构成和外观尺寸,从理论上确定了装置包括成像处注量率、成像距离及相应视场等关键参数.

  3. Coupling of a System Analysis with a Neutronics Analysis for Conceptual Study of Fusion- Driven Transmutation Reactor

    International Nuclear Information System (INIS)

    A compact tokamak reactor concept as a 14 MeV neutron source is desirable from an economic viewpoint for a fusion-driven transmutation reactor. For the optimal design of a reactor, a radial build of reactor components has to be determined by considering the plasma physics and engineering constraints which interrelate various reactor components. In a transmutation reactor, design of blanket and shield play a key role in determining the size of a reactor; the blanket should produce enough tritium for tritium self-sufficiency, the transmutation rate of waste has to be maximized, and the shield should provide sufficient protection for the superconducting toroidal field (TF) coil. To determine the radial build of the blanket and the shield, not only a radiation transport analysis but also a burn-up calculation were coupled with the system analysis and it allowed the self-consistent determination of the design parameters of a transmutation reactor. For neutronic optimization of the blanket and the shield, the quantities such as the tritium breeding ratio (TBR), nuclear heating, radiation damage to the toroidal field coil have to be calculated and burn-up rates of Li, actinides and fission products have to be calculated. Thus the neutronic analysis need to be coupled in the system analysis. In most of the previous system studies, neutronic calculation and plasma analysis are performed separately, so blanket and shield size was determined independently from the reactor size. In this work, to account for the interrelation of blanket and shield with the other components of a reactor system, we coupled the system analysis with one-dimensional neutronic calculation to determine the reactor parameters in self consistent manner. LAR (Low Aspect Ratio) tokamak plasma has the potential of high β operation with high bootstrap current fractions. In the LAR tokamak reactor, the radial build of TF coil(TFC) and the shield play a key role in determining the size of a reactor since it

  4. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  5. Conversion factors from counts to chemical ratios for the EURITRACK tagged neutron inspection system

    Energy Technology Data Exchange (ETDEWEB)

    El Kanawati, W. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Perot, B., E-mail: bertrand.perot@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Carasco, C.; Eleon, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Valkovic, V. [A.C.T.d.o.o., Prilesje 4, 10000 Zagreb (Croatia); Sudac, D.; Obhodas, J. [Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia)

    2011-10-21

    The EURopean Illicit TRAfficking Countermeasures Kit (EURITRACK) uses 14 MeV neutrons produced by the {sup 3}H(d,n){sup 4}H fusion reaction to detect explosives and narcotics in cargo containers. Reactions induced by fast neutrons produce gamma rays, which are detected in coincidence with the associated alpha particle to determine the neutron direction. In addition, the neutron path length is obtained from a time-of-flight measurement, thus allowing the origin of the gamma rays inside the container to be determined. Information concerning the chemical composition of the target material is obtained from the analysis of the energy spectrum. The carbon, oxygen, and nitrogen relative count contributions must be converted to chemical proportions to distinguish illicit and benign organic materials. An extensive set of conversion factors based on Monte Carlo numerical simulations has been calculated, taking into account neutron slowing down and photon attenuation in the cargo materials. An experimental validation of the method is presented by comparing the measured chemical fractions of known materials, in the form of bare samples or hidden in a cargo container, to their real chemical composition. Examples of application to real cargo containers are also reported, as well as simulated data with explosives and illicit drugs.

  6. Dependence of RBE and OER on neutron energy for damage to mammalian cells and plant systems

    International Nuclear Information System (INIS)

    The picture is complicated by the fact that some experiments are performed with monoenergetic neutrons, while others are performed with cyclotron-produced or fission neutrons which involves a wide energy range; it is then an arbitrary decision to use mean, maximum, modal energy etc. However, these difficulties aside, a clear picture emerges. The most biologically effective neutrons have an energy of about 340 keV. RBE falls off below this energy because many of the recoil protons have an energy less than 100 keV, necessary for the maximum proton LET at their Bragg peak. Above 340 keV, RBE falls off because the neutrons produce recoil protons of higher and higher energy which are relatively sparsely ionizing. This process is mitigated to some extent above about 8 MeV by the increasing importance of spallation products. Thus, the variation of both OER and RBE with neutron energy are reasonably well documented and tolerably well understood in terms of the basic physics of energy deposition

  7. Improvement on the calculation of D2O moderated critical systems with new thermal neutron scattering libraries

    International Nuclear Information System (INIS)

    Highlights: • We analize the performance of neutron scattering libraries for D and O in D2O for nuclear criticality calculations. • We calculated 65 ICSBEP benchmark cases from 8 heavy water moderated thermal systems using MCNP5. • A significant improvement is found when our library is combined with the ROSFOND-2010 evaluation for deuterium. • In 48 of the 65 benchmark cases we obtained a C/E ratio closer to 1.0. • The percentage of benchmark cases calculated within 1-sigma increases from 42% to 82%, compared to ENDF/B-VII calculations. - Abstract: To improve the evaluations in thermal sublibraries, we developed a set of thermal neutron scattering cross sections (scattering kernels) for the deuterium and oxygen bound in heavy water in the ENDF-6 format. These new libraries are based on molecular dynamics simulations and recent experimental data, and result in an improvement of the calculation of single neutron scattering quantities. In this work, we show how the use of this new set of cross sections also improves the calculation of thermal critical systems moderated and/or reflected with heavy water. The use of the new thermal scattering library for heavy water, combined with the ROSFOND-2010 evaluation of the deuterium cross sections, results in an improvement of the C/E ratio in 48 out of 65 benchmark cases calculated with the Monte Carlo code MCNP5, in comparison with the existing library based on the ENDF/B-VII evaluation

  8. Estimation of subcriticality and fuel concentration by using 'pattern matching' of neutron flux distribution under non uniformed system

    International Nuclear Information System (INIS)

    In nuclear fuel reprocessing plants, monitoring the spatial profile of neutron flux to infer subcriticality and distribution of fuel concentration using detectors such as PSPC, is very beneficial in sight of criticality safety. In this paper a method of subcriticality and fuel concentration estimation which is supposed to use under non-uniformed system is proposed. Its basic concept is the pattern matching between measured neutron flux distribution and beforehand calculated one. In any kind of subcriticality estimation, we can regard that measured neutron counts put any kind of black box, and then this black box outputs subcriticality. We proposed the use of artificial neural network or 'pattern matching' as black box which have no theoretical clear base. These method are wholly based on the calculated value as recently advancement of computer code accuracy for criticality safety. The most difference between indirect bias estimation method and our method is that our new approach target are the unknown non-uniform system. (J.P.N.)

  9. NE-213-scintillator-based neutron detection system for diagnostic measurements of energy spectra for neutrons having energies greater than or equal to 0.8 MeV created during plasma operations at the Princeton Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    A system for making diagnostic measurements of the energy spectra of greater than or equal to 0.8-MeV neutrons produced during plasma operations of the Princeton Tokamak Fusion Test Reactor (TFTR) has been fabricated and tested and is presently in operation in the TFTR Test Cell Basement. The system consists of two separate detectors, each made up of cells containing liquid NE-213 scintillator attached permanently to RCA-8850 photomultiplier tubes. Pulses obtained from each photomultiplier system are amplified and electronically analyzed to identify and separate those pulses due to neutron-induced events in the detector from those due to photon-induced events in the detector. Signals from each detector are routed to two separate Analog-to-Digital Converters, and the resulting digitized information, representing: (1) the raw neutron-spectrum data; and (2) the raw photon-spectrum data, are transmited to the CICADA data-acquisition computer system of the TFTR. Software programs have been installed on the CICADA system to analyze the raw data to provide moderate-resolution recreations of the energy spectrum of the neutron and photon fluences incident on the detector during the operation of the TFTR. A complete description of, as well as the operation of, the hardware and software is given in this report

  10. THERMAL NEUTRON BACKSCATTER IMAGING.

    Energy Technology Data Exchange (ETDEWEB)

    VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

    2004-10-16

    Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

  11. Parameterising root system growth models using 2D neutron radiography images

    Science.gov (United States)

    Schnepf, Andrea; Felderer, Bernd; Vontobel, Peter; Leitner, Daniel

    2013-04-01

    Root architecture is a key factor for plant acquisition of water and nutrients from soil. In particular in view of a second green revolution where the below ground parts of agricultural crops are important, it is essential to characterise and quantify root architecture and its effect on plant resource acquisition. Mathematical models can help to understand the processes occurring in the soil-plant system, they can be used to quantify the effect of root and rhizosphere traits on resource acquisition and the response to environmental conditions. In order to do so, root architectural models are coupled with a model of water and solute transport in soil. However, dynamic root architectural models are difficult to parameterise. Novel imaging techniques such as x-ray computed tomography, neutron radiography and magnetic resonance imaging enable the in situ visualisation of plant root systems. Therefore, these images facilitate the parameterisation of dynamic root architecture models. These imaging techniques are capable of producing 3D or 2D images. Moreover, 2D images are also available in the form of hand drawings or from images of standard cameras. While full 3D imaging tools are still limited in resolutions, 2D techniques are a more accurate and less expensive option for observing roots in their environment. However, analysis of 2D images has additional difficulties compared to the 3D case, because of overlapping roots. We present a novel algorithm for the parameterisation of root system growth models based on 2D images of root system. The algorithm analyses dynamic image data. These are a series of 2D images of the root system at different points in time. Image data has already been adjusted for missing links and artefacts and segmentation was performed by applying a matched filter response. From this time series of binary 2D images, we parameterise the dynamic root architecture model in the following way: First, a morphological skeleton is derived from the binary

  12. Coupled moderator neutronics

    International Nuclear Information System (INIS)

    Optimizing the neutronic performance of a coupled-moderator system for a Long-Pulse Spallation Source is a new and challenging area for the spallation target-system designer. For optimal performance of a neutron source, it is essential to have good communication with instrument scientists to obtain proper design criteria and continued interaction with mechanical, thermal-hydraulic, and materials engineers to attain a practical design. A good comprehension of the basics of coupled-moderator neutronics will aid in the proper design of a target system for a Long-Pulse Spallation Source

  13. Laser inertial fusion-based energy: Neutronic design aspects of a hybrid fusion-fission nuclear energy system

    Science.gov (United States)

    Kramer, Kevin James

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 mum of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb 83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles having a packing fraction of 20% in 2 cm diameter fuel pebbles. The fission blanket is cooled by

  14. Complementary system for monitoring and control of neutron flux during a fuel outage and during reactor start up stage

    International Nuclear Information System (INIS)

    The present work is an example for that, how with modern technical instruments is possible to compensate disadvantage and to increase technical resources of the old systems, without a change of given system totally with new one. The system detail design and implementation was possible mostly, due to the international conferences and courses organised by IAEA and technical information provided by the agency. The designed system plays a role of complementary system to the in-situ operational systems for monitoring and control of the reactor core neutron flux, allowing its measurement and control during a fuel outage and during reactor start up stage. Additionally, the system recalculates the reactivity in beta units and according to its value the reactor criticality fixed up reactivity is defined. (author)

  15. Ferro-deformation at the nuclear system with protons, Z = 20 and neutrons, N = 40: 60Ca

    CERN Document Server

    Moon, Chang-Bum

    2016-01-01

    We present a possibility that the system with Z = 20, N = 40, 60Ca, has a large deformation, even though it has both proton and neutron magic numbers, symbolizing a spherical nucleus. This large deformation corresponds to the so-called ferro-deformation that occurs at the particular critical points over the nuclear chart. By comparisons with the ferra-deformation at the critical point Z = 40, N = 64 [arXiv:1604.02786], we draw a conclusion that shape phase transitions should occur at Z = 18 or 20 when N = 36 to 38, which leads to a ferro-deformation at the critical points of Z = 18 or 20, N = 40; 58Ar, 60Ca. We explain the shape phase transition in terms of isospin dependent spin-orbital interactions between neutrons in the f5/2 orbital and protons in the f7/2 orbital. We find a universal behavior over the nuclear chart for yielding the ferro-deformation such that; Z = 64, N = 104, Z = 40, N = 64, and Z = 20, N = 40, respectively. This feature is linked to concept of the neutron(n)-proton(p)interaction in spi...

  16. Development of a hybrid MSGC detector for thermal neutron imaging with a MHz data acquisition and histogramming system

    CERN Document Server

    Gebauer, B; Richter, G; Levchanovsky, F V; Nikiforov, A

    2001-01-01

    For thermal neutron imaging at the next generation of high-flux pulsed neutron sources a large area and fourfold segmented, hybrid, low-pressure, two-dimensional position sensitive, microstrip gas chamber detector, fabricated in a multilayer technology on glass substrates, is presently being developed, which utilizes a thin composite sup 1 sup 5 sup 7 Gd/CsI neutron converter. The present article focusses on the readout scheme and the data acquisition (DAQ) system. For position encoding, interpolating and fast multihit delay line based electronics is applied with up to eightfold sub-segmentation per geometrical detector segment. All signals, i.e. position, time-of-flight and pulse-height signals, are fed into deadtime-less 8-channel multihit TDC chips with 120 ps LSB via constant fraction and time-over-threshold discriminators, respectively. The multihit capability is utilized to raise the count rate limit in combination with a sum check algorithm for disentangling pulses from different events. The first vers...

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  18. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); King, Michael; Rossi, Paolo (Sandia National Laboratories, Albuquerque, NM); McDaniel, Floyd Del (Sandia National Laboratories, Albuquerque, NM); Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM); Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  19. Detecting binary neutron star systems with spin in advanced gravitational-wave detectors

    CERN Document Server

    Brown, Duncan A; Lundgren, Andrew; Nitz, Alexander H

    2012-01-01

    The detection of gravitational waves from binary neutron stars is a major goal of the gravitational-wave observatories Advanced LIGO and Advanced Virgo. Previous searches for binary neutron stars with LIGO and Virgo neglected the component stars' angular momentum (spin). We demonstrate that neglecting spin in matched-filter searches causes advanced detectors to lose more than 3% of the possible signal-to-noise ratio for 59% (6%) of sources, assuming that neutron star dimensionless spins, $cJ/GM^2$, are uniformly distributed with magnitudes between 0 and 0.4 (0.05) and that the neutron stars have isotropically distributed spin orientations. We present a new method of constructing filter banks for advanced-detector searches, which can create template banks of signals with non-zero spins that are (anti-)aligned with the orbital angular momentum. We show that this search loses more than 3% of the maximium signal-to-noise for only 9% (0.2%) of BNS sources with dimensionless spins between 0 and 0.4 (0.05) and isotr...

  20. Los Alamos neutron science user facility - control system risk mitigation & updates

    Energy Technology Data Exchange (ETDEWEB)

    Pieck, Martin [Los Alamos National Laboratory

    2011-01-05

    LANSCE User Facility is seeing continuing support and investments. The investment will sustain reliable facility operations well into the next decade. As a result, the LANSCE User Facility will continue to be a premier Neutron Science Facility at the Los Alamos National Laboratory.

  1. The interpretation of coherent quasielastic neutron scattering experiments on lattice gases and similar systems

    International Nuclear Information System (INIS)

    By examining the physical significance of the chemical of Fick's law diffusion coefficient as compared to the tracer or Einstein equivalent, the role of the chemical potential in the interpretation of coherent quasielastic neutron scattering is emphasised. This approach has been successfully applied to the case of NbDx but has a wide variety of other possible applications. (orig.)

  2. Gamma Scintillator System Enhancement for Neutron Detection using Boron Carbide for Homeland Security

    International Nuclear Information System (INIS)

    An efficient and low cost 10B based thermal neutron detector as a replacement for 3He based neutron detectors is suggested. The detection is based on an enhancement to a scintillator gamma-rays detector. 3He supply for neutron detectors is gradually become harder to obtain(1) since the commercial production of this isotope has been practically ended. The 10B(n, )7Li interaction is characterized with two energetic ion and a 478 keV gamma photon which is emitted from the excited 7Li in 94% of the interactions(2). A tailored Monte-Carlo code for the detector model was written in MATLAB in order to assess the detector's efficiency. The simulation model is based on ENDF/B-VII.0(3) libraries for neutrons cross sections, and XCOM(4) database for gamma absorption coefficients. By varying the B4C thickness, optimal efficiency was obtained both for natural occurring 10B compound with atomic abundance of 19.8% as well as for boron-10 enriched to 96%

  3. SU-C-204-05: Simulations of a Portal Imaging System for Conformal and Intensity Modulated Fast Neutron Therapy

    International Nuclear Information System (INIS)

    Purpose: The University of Washington Medical Center offers neutron therapy for the palliative and definitive treatment of selected cancers. In vivo field verification has the potential to improve the safe and effective delivery of neutron therapy. We propose a portal imaging method that relies on the creation of positron emitting isotopes (11C and 15O) through (n, 2n) reactions with a PMMA plate placed below the patient. After field delivery, the plate is retrieved from the vault and imaged using a reader that detects annihilation photons. The spatial pattern of activity produced in the PMMA plate provides information to reconstruct the neutron fluence map needed to confirm treatment delivery. Methods: We used MCNP to simulate the accumulation of 11C activity in a slab of PMMA 2 mm thick, and GATE was used to simulate the sensitivity and spatial resolution of a prototype imaging system. BGO crystal thicknesses of 1 cm, 2 cm and 3 cm were simulated with detector separations of 2 cm. Crystal pitches of 2 mm and 4 mm were evaluated. Back-projection of the events was used to create a planar image. The spatial resolution was taken to be the FWHM of the reconstructed point source image. Results: The system sensitivity for a point source in the center of the field of view was found to range from 58% for 1 cm thick BGO with 2 mm crystal pitch to 74% for the 3 cm thick BGO crystals with 4 mm crystal pitch. The spatial resolution at the center of the field of view was found to be 1.5 mm for the system with 2 mm crystal pitch and 2.8 mm for the system with the 4 mm crystal pitch. Conclusion: BGO crystals with 4 mm crystal pitch and 3 cm length would offer the best sensitivity reader

  4. A flag-based algorithm and associated neutron interrogation system for the detection of explosives in sea–land cargo containers

    International Nuclear Information System (INIS)

    Recent efforts in the simulation of sea–land cargo containers in active neutron interrogation scenarios resulted in the identification of several flags indicating the presence of conventional explosives. These flags, defined by specific mathematical manipulations of the neutron and photon spectra, have been combined into a detection algorithm for screening cargo containers at international borders and seaports. The detection algorithm's steps include classifying the cargo type, identifying containers filled with explosives, triggering in the presence of concealed explosives, and minimizing the number of false positives due to cargo heterogeneity. The algorithm has been implemented in a system that includes both neutron and photon detectors. This system will take about 10 min to scan a container and cost approximately $1M to construct. Dose calculations resulted in estimates of less than 0.5 mSv for a person hidden in the container, and an operator annual dose of less than 0.9 mSv. - Highlights: • Monte Carlo model of explosives screening in cargo containers using fast neutrons. • Monte Carlo model also explores neutron detector response. • Development of an explosives detection algorithm using active neutron interrogation. • Implementation of the algorithm, including equipment, infrastructure, cost and dose. • System will cost ~1M USD and an entire container may be scanned in ~10 min

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

    International Nuclear Information System (INIS)

    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

  6. Neutron Capture and Neutron Halos

    OpenAIRE

    A.Mengoni; Otsuka, T; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Ishihara, M.

    1996-01-01

    The connection between the neutron halo observed in light neutron rich nuclei and the neutron radiative capture process is outlined. We show how nuclear structure information such as spectroscopic factors and external components of the radial wave function of loosely bound states can be derived from the neutron capture cross section. The link between the direct radiative capture and the Coulomb dissociation process is elucidated.

  7. The Probability Distribution of Binary Pulsar Coalescence Rates. I. Double Neutron Star Systems in the Galactic Field

    OpenAIRE

    Kim, C.; Kalogera, V.; Lorimer, D.R.

    2002-01-01

    Estimates of the Galactic coalescence rate (R) of close binaries with two neutron stars (NS-NS) are known to be uncertain by large factors (about two orders of magnitude) mainly due to the small number of systems detected as binary radio pulsars. We present an analysis method that allows us to estimate the Galactic NS-NS coalescence rate using the current observed sample and, importantly, to assign a statistical significance to these estimates and to calculate the allowed ranges of values at ...

  8. MCNP simulations of fast neutron scattering by various elements and their compounds in view of elaboration of a single shot inspection system

    International Nuclear Information System (INIS)

    Plasma-focus device is intended to be used in a single shot inspection system for a detection of hidden explosives. Fast neutrons emitted during a short, intense pulse are scattered by the investigated object. Unfolding of the elemental content of unknown bulk sample should be possible from the recorded energy spectrum of the scattered neutrons. The time-of-flight detection technique can be involved in the identification procedure. Numerical Monte Carlo simulations of fast (2.45 and 14 MeV) neutron scattering by various elements and their combinations have been performed. Examples of results obtained using the MCNP code are presented in the paper in the form of the scattered neutron energy and TOF spectra registered by a hypothetic detector at 1 m distance. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-01-11

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

  10. Development of Neutron Guides in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yeong Garp; Shin, Jin Won; Cho, Sang-Jin; Oh, Jong-Myeong; Ryu, Jeong Soo; Seong, Baek-Seok; Kim, Hak-Sung; Lee, Jung-Hee; Kim, Min-Jin; Kim, Hyun-Jun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    The cold neutron guide systems, as a part of the cold neutron research facilities in HANARO, have been being developed since 2003. Until early 2008, the beam port assigned for the cold neutron (CN) has been used for an 8-m SANS instrument without a neutron guide. All the hardware for the CN beam line will be replaced with a completely new system composed of neutron guides, an in-pile plug, a primary shutter, shielding blocks, and vacuum systems. This paper summarizes the technical status of the development for the cold neutron guide and the related systems that are mostly ready for an installation from 2008.

  11. Neutronics analyses for fast spectrum nuclear systems and scenario studies for advanced nuclear fuel cycles

    OpenAIRE

    Grasso, Giacomo

    2010-01-01

    The present PhD thesis summarizes the three-years study about the neutronic investigation of a new concept nuclear reactor aiming at the optimization and the sustainable management of nuclear fuel in a possible European scenario. A new generation nuclear reactor for the nuclear reinassance is indeed desired by the actual industrialized world, both for the solution of the energetic question arising from the continuously growing energy demand together with the corresponding reduction of oil ava...

  12. Characterization of conformational properties of protein/trehalose/water system by neutron scattering

    CERN Document Server

    Brandt, A; Mangione, A; Migliardo, F; Vertessy, B G

    2002-01-01

    In this contribution we report results of a small-angle neutron scattering (SANS) investigation of dUTPase/D sub 2 O solutions. Data were collected by the V4 spectrometer at the BENSC facility (Berlin, Germany). The results allow us to characterize the conformational properties of the protein in solution as a function of temperature and in the presence of trehalose, a disaccharide with a noticeable bioprotective action. (orig.)

  13. Developing plan and pre-conceptual design of target system for JAERI`s high intensity neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Hino, Ryutaro; Kaminaga, Masanori; Haga, Katsuhiro; Ishikura, Syuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakamura, Fumito; Uchida, Shoji

    1997-11-01

    This paper presents an outline of developing plan of a target system and topics obtained by a pre-conceptual design, which aims to establish a technology base of the target system and to make clear a system concept. In the plan, two types of target - solid and mercury targets - are to be developed for a neutron scattering facility. Information obtained through the development shall be applied to designs of an irradiation and a transmutation facilities. Through the pre-conceptual design, system arrangement, scale etc. were made clear: total weight will be 12000 ton, and 26 beam lines with beam shutters will be equipped for 4 moderators. Engineering problems were also made clear through the design; high flux heat removal, dynamic stress caused by thermal shock and pressure wave, loop technology for the mercury target and a slurry moderator consisting of methane pellets and liquefied hydrogen. We are now constructing new test apparatuses and arranging computer codes for solving these problems. (author)

  14. Characterization of hydrogen storage materials and systems with photons and neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Pranzas, P. Klaus; Boesenberg, Ulrike; Karimi, Fahim; Muenning, Martin; Metz, Oliver; Minella, Christian Bonatto; Schmitz, Heinz-Werner; Beckmann, Felix; Bormann, Ruediger; Klassen, Thomas; Dornheim, Martin; Schreyer, Andreas [Helmholtz-Zentrum Geesthacht (Germany). Centre for Materials and Coastal Research; Vainio, Ulla; Zajac, Dariusz; Welter, Edmund [HASYLAB/DESY, Hamburg (Germany); Jensen, Torben R. [Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, University of Aarhus (Denmark); Cerenius, Yngve [MAX-lab, Lund University (Sweden)

    2011-08-15

    Complex hydrides are very promising candidates for future light-weight solid state hydrogen storage materials. The present work illustrates detailed characterization of such novel hydride materials on different size scales by the use of synchrotron radiation and neutrons. The comprehensive analysis of such data leads to a deep understanding of the ongoing processes and mechanisms. The reaction pathways during hydrogen desorption and absorption are identified by in situ X-ray diffraction (XRD). Function and size of additive phases are estimated using X-ray absorption spectroscopy (XAS) and anomalous small-angle X-ray scattering (ASAXS). The structure of the metal hydride matrix is characterized using (ultra) small-angle neutron scattering (SANS/USANS). The hydrogen distribution in tanks filled with metal hydride material is studied with neutron computerized tomography (NCT). The results obtained by the different analysis methods are summarized in a final structural model. The complementary information obtained by these different methods is essential for the understanding of the various sorption processes in light metal hydrides and hydrogen storage tanks. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Neutron spectrum adjustment using reaction rate data acquired with a liquid dosimetry system

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L. [Argonne National Lab., IL (United States); Ikeda, Y.; Uno, Y.; Maekawa, F. [JAERI, Tokai (Japan)

    1997-08-01

    A dosimetry technique based on neutron activation of circulating water with dissolved salts is discussed. The neutron source was the FNS accelerator at JAERI, Tokai, Japan. Yttrium chloride hexahydrate (YCl{sub 3{center_dot}}6H{sub 2}O) was the salt (264.9 grams dissolved in 16.094 liters of water). Gamma-ray yields were measured with an intrinsic Ge detector. The following reactions were examined: (1) {sup 16}O(n,p){sup 16}N (E{sub thresh} = 10.245 MeV, t{sub 1/2} = 7.13 sec, E{sub {gamma}} = 6.129 MeV); (2) {sup 37}Cl(n,p){sup 37}S (E{sub thresh} = 4.194 MeV, t{sub 1/2} = 5.05 min, E{sub {gamma}} = 3.104 MeV); (3) {sup 89}Y(n,n{prime}){sup 89m}Y (E{sub thresh} = 0.919 MeV, t{sub 1/2} = 16.06 sec, E{sub {gamma}} = 0.909 MeV). This paper describes use of the generalized least-squares (GLS) method to adjust the neutron spectrum.

  16. Mechanochemical synthesis in the Li-Mg-N-D system under deuterium gas: a neutron diffraction study.

    Science.gov (United States)

    Li, Z; Zhang, J; Latroche, M; Wang, S; Jiang, L; Du, J; Cuevas, F

    2016-09-14

    The Mg(NH2)2/2LiH mixture is considered as one of the most valuable reversible hydrogen storage systems for feeding PEM fuel cells. In this paper, we investigate the mechanochemical synthesis in the Li-Mg-N-H system under deuterium gas, using Li3N and Mg as reactants, and the structural and sorption properties of the intermediate and final products mainly by means of neutron powder diffraction. Mechanochemistry leads to the end formation of amorphous Mg(ND2)2, which crystallizes upon heating above 425 K. During synthesis, a novel cation-mixed nitride/imide phase of simplified composition Li3MgN2D has been unveiled as the intermediate phase. It crystallizes in the cubic disordered anti-fluorite type structure (S.G. Fm3[combining macron]m) with a lattice parameter of 4.996 Å at room temperature. Deuterium absorption in this compound occurs through an original solid solution type mechanism ending with the imide compound β-Li2MgN2D2. The conjoint use of mechanochemistry under deuterium gas and in situ neutron diffraction techniques offers new avenues for better characterization of the efficient hydrogen storage materials. In particular, this work highlights the unexpected role of intermediate nitride/imide phases in the Li-Mg-N-H system.

  17. Novel neutron focusing mirrors for compact neutron sources

    OpenAIRE

    Gubarev, M. V.; Zavlin, V. E.; Katz, R.; Resta, G.; Robertson, L; Crow, L.; Ramsey, B. D.; Khaykovich, Boris; Liu, DaZhi; Moncton, David E.

    2012-01-01

    We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. A system containing four nested Ni mirror pairs was implemented and tested by focusing a polychromatic neutron beam at the MIT Reactor and conducting an imaging experiment at HFIR. The major advantage of the Wolter mirrors is the possibility of nesting for large angular c...

  18. Magnetic non-collinear neutron wave resonator

    CERN Document Server

    Khaidukov, Yu N

    2009-01-01

    The expression are received for amplitude of neutron reflection from layered magnetic non-collinear structure (neutron wave resonator (NWR)). It is showed the magnetic non-collinear NWR is characterized by the system of pairs of resonances for the spin flipped neutrons. The conditions are defined at which amplifying of spin-flipped neutron flux in wave resonator is multiple increased in comparison with amplifying of neutron absorption.

  19. Development of a fast neutron imaging system for investigating two-phase flows in nuclear thermal–hydraulic phenomena: A status report

    International Nuclear Information System (INIS)

    Highlights: • Development of a novel fast neutron imaging system for two-phase flows in fuel bundles. • Novel D–D fusion neutron generator with small emitting spot for imaging. • Dedicated fast neutron imaging detector based on plastic scintillator and SiPM. • Novel proton recoil converter coupled with THGEM readout as imaging detector. - Abstract: The present paper gives an overview of the status of an ongoing project aiming at the development of a fast neutron imaging system for investigating two-phase flows primarily in the context of nuclear fuel bundle development. Other potential subjects for investigations include steam explosions for severe accident research and liquid metal two-phase flows for Gen IV reactor systems. The project is carried out in the form of a feasibility study that should enable estimation of the ultimate imaging capabilities achievable. The imaging system used in the feasibility study consists of a compact, deuterium–deuterium fusion based neutron generator and dedicated imaging detectors. For the latter two promising concepts are developed in parallel: one is based on an array of plastic scintillators coupled with silicon photomultipliers, the other on a special multi-foil recoil proton converter coupled to a position sensitive charge readout using a micro pattern gas detector

  20. Simultaneous observations of a pair of kilohertz QPOs and a plausible 1860 Hz QPO from an accreting neutron star system

    CERN Document Server

    Bhattacharyya, Sudip

    2009-01-01

    We report an indication (3.22 sigma) of ~ 1860 Hz quasi-periodic oscillations from a neutron star low-mass X-ray binary 4U 1636-536. If confirmed, this will be by far the highest frequency feature observed from an accreting neutron star system, and hence could be very useful to understand such systems. This plausible timing feature was observed simultaneously with lower (~ 585 Hz) and upper (~ 904 Hz) kilohertz quasi-periodic oscillations. The two kilohertz quasi-periodic oscillation frequencies had the ratio of ~ 1.5, and the frequency of the alleged ~ 1860 Hz feature was close to the triple and the double of these frequencies. This can be useful to constrain the models of all the three features. In particular, the ~ 1860 Hz feature could be (1) from a new and heretofore unknown class of quasi-periodic oscillations, or (2) the first observed overtone of lower or upper kilohertz quasi-periodic oscillations. Finally we note that, although the relatively low significance of the ~ 1860 Hz feature argues for caut...