WorldWideScience

Sample records for prompt neutron generation

  1. Prompt-period measurement of the Annular Core Research Reactor prompt neutron generation time

    International Nuclear Information System (INIS)

    Coats, R.L.; Talley, D.G.; Trowbridge, F.R.

    1994-07-01

    The prompt neutron generation time for the Annular Core Research Reactor was experimentally determined using a prompt-period technique. The resultant value of 25.5 μs agreed well with the analytically determined value of 24 μs. The three different methods of reactivity insertion determination yielded ±5% agreement in the experimental values of the prompt neutron generation time. Discrepancies observed in reactivity insertion values determined by the three methods used (transient rod position, relative delayed critical control rod positions, and relative transient rod and control rod positions) were investigated to a limited extent. Rod-shadowing and low power fuel/coolant heat-up were addressed as possible causes of the discrepancies

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

    Science.gov (United States)

    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 nitrog...

  3. Development of a new deuterium-deuterium (D-D) neutron generator for prompt gamma-ray neutron activation analysis.

    Science.gov (United States)

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    A new deuterium-deuterium (D-D) neutron generator has been developed by Adelphi Technology for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA), and fast neutron radiography. The generator makes an excellent fast, intermediate, and thermal neutron source for laboratories and industrial applications that require the safe production of neutrons, a small footprint, low cost, and small regulatory burden. The generator has three major components: a Radio Frequency Induction Ion Source, a Secondary Electron Shroud, and a Diode Accelerator Structure and Target. Monoenergetic neutrons (2.5MeV) are produced with a yield of 10(10)n/s using 25-50mA of deuterium ion beam current and 125kV of acceleration voltage. The present study characterizes the performance of the neutron generator with respect to neutron yield, neutron production efficiency, and the ionic current as a function of the acceleration voltage at various RF powers. In addition the Monte Carlo N-Particle Transport (MCNP) simulation code was used to optimize the setup with respect to thermal flux and radiation protection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection

    Science.gov (United States)

    Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with...

  5. Prompt neutron emission

    International Nuclear Information System (INIS)

    Sher, R.

    1959-01-01

    It is shown that Ramanna and Rao's tentative conclusion that prompt fission neutrons are emitted (in the fragment system) preferentially in the direction of fragment motion is not necessitated by their angular distribution measurements, which are well explained by the usual assumptions of isotropic emission with a Maxwell (or Maxwell-like) emission spectrum. The energy distribution (Watt spectrum) and the angular distribution, both including the effects of anisotropic emission, are given. (author) [fr

  6. 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). 2010 Elsevier Ltd. All rights reserved.

  7. Study of the prompt gamma ray signal from fissions in special nuclear materials induced using an associated particle neutron generator

    International Nuclear Information System (INIS)

    Koltick, D. S.; Kane, S. Z.

    2009-01-01

    More than 42 million cargo containers entered the United States in 2005. To search for a few kilograms of special nuclear material (SNM) within this vast stream of cargo, an inspection system based on neutron-induced fission followed by the coincident detection of multiple prompt fission gamma rays is investigated using MCNP-Polimi code. The system utilizes two deuterium-tritium (DT) associated particle neutron generators, each capable of 10 9 neutrons/s at 14.1 MeV, with sub-nanosecond timing resolution ZnO:Ga alpha detectors internal to the generator. Because prompt fission signals are approximately 100 times stronger than the delayed signals, the neutron flux is greatly reduced compared to 10 11-12 neutrons/s required for systems based on delayed signals such as the 'nuclear car wash' [4]. In addition the system utilizes 30 cm deep liquid krypton (LKr) noble gas detectors having 94% detection efficiency for 1 MeV gamma rays, high solid angle coverage (∼ 50% of the total solid angle), and sub-nanosecond timing resolution (∼ 600 ps). An algorithm for distinguishing U-235 from U-238 is presented. (authors)

  8. Prompt-gamma neutron activation analysis system design. Effects of D-T versus D-D neutron generator source selection

    International Nuclear Information System (INIS)

    Shypailo, R.J.; Ellis, K.J.

    2008-01-01

    Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with 14.2 MeV neutrons. To compare the performance of these two units in our present PGNA system, we performed Monte Carlo simulations (MCNP-5; Los Alamos National Laboratory) evaluating the nitrogen reactions produced in tissue-equivalent phantoms and the effects of background interference on the gamma-detectors. Monte Carlo response curves showed increased gamma production per unit dose when using the D-D generator, suggesting that it is the more suitable choice for smaller sized subjects. The increased penetration by higher energy neutrons produced by the D-T generator supports its utility when examining larger, especially obese, subjects. A clinical PGNA analysis design incorporating both neutron generator options may be the best choice for a system required to measure a wide range of subject phenotypes. (author)

  9. Prompt fission neutron spectra and average prompt neutron multiplicities

    International Nuclear Information System (INIS)

    Madland, D.G.; Nix, J.R.

    1983-01-01

    We present a new method for calculating the prompt fission neutron spectrum N(E) and average prompt neutron multiplicity anti nu/sub p/ as functions of the fissioning nucleus and its excitation energy. The method is based on standard nuclear evaporation theory and takes into account (1) the motion of the fission fragments, (2) the distribution of fission-fragment residual nuclear temperature, (3) the energy dependence of the cross section sigma/sub c/ for the inverse process of compound-nucleus formation, and (4) the possibility of multiple-chance fission. We use a triangular distribution in residual nuclear temperature based on the Fermi-gas model. This leads to closed expressions for N(E) and anti nu/sub p/ when sigma/sub c/ is assumed constant and readily computed quadratures when the energy dependence of sigma/sub c/ is determined from an optical model. Neutron spectra and average multiplicities calculated with an energy-dependent cross section agree well with experimental data for the neutron-induced fission of 235 U and the spontaneous fission of 252 Cf. For the latter case, there are some significant inconsistencies between the experimental spectra that need to be resolved. 29 references

  10. Prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Goswami, A.

    2003-01-01

    Prompt gamma neutron activation analysis (PGNAA) is a technique for the analysis of elements present in solid, liquid and gaseous samples by measuring the capture gamma rays emitted from the sample during neutron irradiation. The technique is complementary to conventional neutron activation analysis (NAA) as it can be used in number of cases where NAA fails. Though the technique was first used in sixties, the advantage of the technique was first highlighted by Lindstrom and Anderson. PGNAA is increasingly being used as a rapid, instrumental, nondestructive and multielement analysis technique. A monograph and several excellent reviews on this topic have appeared recently. In this review, an attempt has been made to bring out the essential aspects of the technique, experimental arrangement and instrumentation involved, and areas of application. Some of the results will also be presented

  11. Performance characteristics of a prompt gamma-ray activation analysis (PGAA) system equipped with a new compact D-D neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Joon; Song, Byung Chul; Im, Hee-Jung [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Dukjin-dong 150-1, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Jong-Yun [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Dukjin-dong 150-1, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)], E-mail: kjy@kaeri.re.kr

    2009-07-21

    A new prompt gamma-ray activation analysis (PGAA) system equipped with a compact deuterium-deuterium (D-D) neutron generator has been developed for fast detection of explosives and chemical warfare agents. The PGAA system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF)-driven ion source. The ionic current of the compact neutron generator was determined as a function of the acceleration voltage at various RF powers. Monoenergetic neutrons (2.45 MeV) with a neutron yield of >1x10{sup 7} n/s were obtained at a deuterium pressure of 8.0 mTorr, an acceleration voltage of 80 kV, and an RF power of 1.1 kW. The performance of the PGAA system was examined by studying the dependence of a prompt gamma-ray count rate on crucial operating parameters.

  12. Prompt neutron emission; Emission des neutrons prompts de fission

    Energy Technology Data Exchange (ETDEWEB)

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

    1959-07-01

    It is shown that Ramanna and Rao's tentative conclusion that prompt fission neutrons are emitted (in the fragment system) preferentially in the direction of fragment motion is not necessitated by their angular distribution measurements, which are well explained by the usual assumptions of isotropic emission with a Maxwell (or Maxwell-like) emission spectrum. The energy distribution (Watt spectrum) and the angular distribution, both including the effects of anisotropic emission, are given. (author) [French] On montre que la conclusion experimentale de Ramanna et Rao selon laquelle les neutrons prompts de fission sont emis (dans le systeme de reference des fragments) preferentiellement dans la direction du mouvement du fragment, ne decoule pas necessairement de leurs mesures de distribution angulaire. Celles-ci sont bien expliquees par l'hypothese classique de l'emission isotrope et d'un spectre d'emission maxwellien (ou quasi-maxwellien). On donne la distribution en energie (ou spectre de Watt) et la distribution angulaire, comprenant toutes les deux les effets d'emission anisotrope. (auteur)

  13. Pulsed neutron uranium borehole logging with prompt fission neutrons

    International Nuclear Information System (INIS)

    Bivens, H.M.; Smith, G.W.; Jensen, D.H.

    1976-01-01

    The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. The necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy

  14. Estimation of neutron energy distributions from prompt gamma emissions

    Science.gov (United States)

    Panikkath, Priyada; Udupi, Ashwini; Sarkar, P. K.

    2017-11-01

    A technique of estimating the incident neutron energy distribution from emitted prompt gamma intensities from a system exposed to neutrons is presented. The emitted prompt gamma intensities or the measured photo peaks in a gamma detector are related to the incident neutron energy distribution through a convolution of the response of the system generating the prompt gammas to mono-energetic neutrons. Presently, the system studied is a cylinder of high density polyethylene (HDPE) placed inside another cylinder of borated HDPE (BHDPE) having an outer Pb-cover and exposed to neutrons. The emitted five prompt gamma peaks from hydrogen, boron, carbon and lead can be utilized to unfold the incident neutron energy distribution as an under-determined deconvolution problem. Such an under-determined set of equations are solved using the genetic algorithm based Monte Carlo de-convolution code GAMCD. Feasibility of the proposed technique is demonstrated theoretically using the Monte Carlo calculated response matrix and intensities of emitted prompt gammas from the Pb-covered BHDPE-HDPE system in the case of several incident neutron spectra spanning different energy ranges.

  15. Prompt Neutron Lifetime for the NBSR Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, A.L.; Diamond, D.

    2012-06-24

    In preparation for the proposed conversion of the National Institute of Standards and Technology (NIST) research reactor (NBSR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, certain point kinetics parameters must be calculated. We report here values of the prompt neutron lifetime that have been calculated using three independent methods. All three sets of calculations demonstrate that the prompt neutron lifetime is shorter for the LEU fuel when compared to the HEU fuel and longer for the equilibrium end-of-cycle (EOC) condition when compared to the equilibrium startup (SU) condition for both the HEU and LEU fuels.

  16. Radiological Safety Aspects of the new Deuterium-Deuterium (D-D) neutron generator for prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Naceur, Ahmed

    2014-01-01

    This document is a safety and a security report for the new neutron generator the High Intensity Mutli-Purpose DD-110 of the National Center for Nuclear Sciences and Technologies of Tunis (CNSTN). It aims to introduce the standards of the International Atomic Energy Agency (IAEA) to the facility in question. Overall, this report draws its profit from the official safety reports of the IAEA. First, we study the anatomy of the accelerator by breaking it down into various compartments and examining the case of leaks that may arise. Thanks to this part, the reader gets used to the peculiarity of the system, and we can meet and provide procedures for some typical scenarios of mechanical malfunction. Second, we adapt some theoretical concepts related to the quantification of the radioactivity, the thickness of the armoring, the utilization factor, and the quality factor. Thus, we become able to list of types of these radiations, dangers, risks and their sources. We treat the production, the cross section, the interaction with the environment and the separated removal of neutrons, gamma, X-photons, beta particles, and electrons. In addition, we examine the phenomenon of activation of the compartments, the danger samples of activation, the danger associated with the modulation of the pressure and the danger of explosion. In light of this study, we handle mathematically the question of the armoring and the concept of radiation protection. Therefore, we present a practical methodology to implement a monitoring system and a technicality in the interpretation of the measurements. Finally, we discuss the practical aspect by introducing security governance to CNSTN, and establishing a program of general, radiological and specific security.

  17. MADNIX a code to calculate prompt fission neutron spectra and average prompt neutron multiplicities

    International Nuclear Information System (INIS)

    Merchant, A.C.

    1986-03-01

    A code has been written and tested on the CDC Cyber-170 to calculate the prompt fission neutron spectrum, N(E), as a function of both the fissioning nucleus and its excitation energy. In this note a brief description of the underlying physical principles involved and a detailed explanation of the required input data (together with a sample output for the fission of 235 U induced by 14 MeV neutrons) are presented. Weisskopf's standard nuclear evaporation theory provides the basis for the calculation. Two important refinements are that the distribution of fission-fragment residual nuclear temperature and the cooling of the fragments as neutrons are emitted approximately taken into account, and also the energy dependence of the cross section for the inverse process of compound nucleus formation is included. This approach is then used to calculate the average number of prompt neutrons emitted per fission, v-bar p . At high excitation energies, where fission is still possible after neutron emission, the consequences of the competition between first, second and third chance fission on N(E) and v-bar p are calculated. Excellent agreement with all the examples given in the original work of Madland and Nix is obtained. (author) [pt

  18. Prompt neutrons from {sup 236}U fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Boldeman, J W; Musgrove, A.R. de L.; Walsch, R L

    1971-03-01

    Measurements were made of prompt neutron emission in the thermal neutron fission of {sup 235}U. The mean neutron emission per fragment was obtained for particular values of the fragment mass and total kinetic energy. A direct neutron counting method was employed and a comparison made with data from previous experiments of this type. (author)

  19. Prompt gamma-based neutron dosimetry for Am-Be and other workplace neutron spectra

    International Nuclear Information System (INIS)

    Udupi, Ashwini; Panikkath, Priyada; Sarkar, P.K.

    2016-01-01

    A new field-deployable technique for estimating the neutron ambient dose equivalent H*(10) by using the measured prompt gamma intensities emitted from borated high-density polyethylene (BHDPE) and the combination of normal HDPE and BHDPE with different configurations have been evaluated in this work. Monte Carlo simulations using the FLUKA code has been employed to calculate the responses from the prompt gammas emitted due to the monoenergetic neutrons interacting with boron, hydrogen, and carbon nuclei. A suitable linear combination of these prompt gamma responses (dose conversion coefficient (DCC)-estimated) is generated to approximate the International Commission on Radiological Protection provided DCC using the cross-entropy minimization technique. In addition, the shape and configurations of the HDPE and BHDPE combined system are optimized using the FLUKA code simulation results. The proposed method is validated experimentally, as well as theoretically, using different workplace neutron spectra with a satisfactory outcome. (author)

  20. Physical basis for prompt-neutron activation analysis

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1982-01-01

    The technique called prompt ν-ray neutron activation analysis has been applied to rapid materials analysis. The radiation following the neutron radiation capture is prompt in the sense that the nuclear decay time is on the order of 10 - 15 second, and thus the technique is not strictly activation, but should be called radiation neutron capture spectroscopy or neutron capture ν-ray spectroscopy. This paper reviews the following: sources and detectors, theory of radiative capture, nonstatistical capture, giant dipole resonance, fast neutron capture, and thermal neutron capture ν-ray spectra. 14 figures

  1. Lifetime measurement of prompt neutrons using the neutronic noise analysis

    International Nuclear Information System (INIS)

    Ortiz Servin, J.J.

    1992-01-01

    The purpose of this work is to estimate the life of the prompt neutrons, i, of a nuclear reactor utilizing the neutron noise analysis. This technique carry to development of mathematical model that is valid for lower powers reactor. The equation resulting convey to the observation about power spectrum behaviour respect to the frecquency. In this case, the reactor in study is the Triga Mark III of Nuclear Center of Mexico that it was provided of fission chambers for register the neutron fluxes. These fluxes was digitized and storage in computer disc as signals dependents of time, for later apply the Fourier Transformation and obtain the spectras. The spectras measured to different reactor powers were adjusted to the development equation before, using the method of square minimum and so estimate the parameter i. The analysis of results throw a value of 22.73 +/- 0.92 μs. On the other hand, the calculate value to the resolve the kinetic equation of reactor defer in lower than 4 % about the estimate. Of this, it concludes that the model utilized is trusty with a good mistake margin, moreover of that the technique of Neutron Noise analysis demonstrate be competitive (Author)

  2. Source Correlated Prompt Neutron Activation Analysis for Material Identification and Localization

    Science.gov (United States)

    Canion, Bonnie; McConchie, Seth; Landsberger, Sheldon

    2017-07-01

    This paper investigates the energy spectrum of photon signatures from an associated particle imaging deuterium tritium (API-DT) neutron generator interrogating shielded uranium. The goal is to investigate if signatures within the energy spectrum could be used to indirectly characterize shielded uranium when the neutron signature is attenuated. By utilizing the correlated neutron cone associated with each pixel of the API-DT neutron generator, certain materials can be identified and located via source correlated spectrometry of prompt neutron activation gamma rays. An investigation is done to determine if fission neutrons induce a significant enough signature within the prompt neutron-induced gamma-ray energy spectrum in shielding material to be useful for indirect nuclear material characterization. The signature deriving from the induced fission neutrons interacting with the shielding material was slightly elevated in polyethylene-shielding depleted uranium (DU), but was more evident in some characteristic peaks from the aluminum shielding surrounding DU.

  3. PNG-300 a nanosecond pulsed neutron generator

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  4. Applicability of the activation analysis with prompt neutron in medicine

    International Nuclear Information System (INIS)

    Yaghubian-Malhami, R.

    1975-04-01

    The concentrations of boron and cadmium in the human body are of great importance in medicine. The author determined their concentration by prompt neutron activation analysis in aqueous solutions and in urine. The results show that this technique may be used in medical diagnosis. The author discusses the qualities and the applicability of delayed and prompt neutron activation analysis in biology and medicine. (C.R.)

  5. The progress of neutron induced prompt gamma analysis technique in 1988-2002

    International Nuclear Information System (INIS)

    Liu Yuren; Jing Shiwei

    2003-01-01

    The new development of the neutron induced prompt gamma-ray analysis (NIPGA) technology in 1988-2002 are described. The pulse fast-thermal neutron activation analysis method, which utilizes the inelastic reaction and capture reaction jointly is employed to measure the elemental content in the material more efficiently. The lifetime of the neutron generator is more than 10000 h and the capability of HPGe, TeZeCd and MCA (multi-channel analyser) reaches the high level. At the same time, Monte Carlo Library least-square method is used to solve the nonlinearity problem in the PGNAA (Prompt Gamma Neutron Activation Analysis)

  6. A method for prediction of prompt fission neutron spectra

    International Nuclear Information System (INIS)

    Grashin, A.F.; Lepeshkin, M.V.

    1988-01-01

    Three-parameter formula for the prompt-fission-neutron integral spectrum is derived from a thermodynamical model. Two parameters, scission-neutron weight p = 11 % and anisotropy factor for accelerated fragments b = 10 %, are determined from experimental data, the same values being assumed for any type of fission. The thermodynamical theory provides the value of the third parameter, temperature τ, thus prognozing neutron spectrum and average energy with an error about 1 %. (author)

  7. Pulsed neutron generator for logging

    International Nuclear Information System (INIS)

    Thibideau, F.D.

    1977-01-01

    A pulsed neutron generator for uranium logging is described. This generator is one component of a prototype uranium logging probe which is being developed by SLA to detect, and assay, uranium by borehole logging. The logging method is based on the measurement of epithermal neutrons resulting from the prompt fissioning of uranium from a pulsed source of 17.6 MeV neutrons. An objective of the prototype probe was that its diameter not exceed 2.75 inches, which would allow its use in conventional rotary drill holes of 4.75-inch diameter. This restriction limited the generator to a maximum 2.375-inch diameter. The performance requirements for the neutron generator specified that it operate with a nominal output of 5 x 10 6 neutrons/pulse at up to 100 pulses/second for a one-hour period. The development of a neutron generator meeting the preliminary design goals was completed and two prototype models were delivered to SLA. These two generators have been used by SLA to log a number of boreholes in field evaluation of the probe. The results of the field evaluations have led to the recommendation of several changes to improve the probe's operation. Some of these changes will require additional development effort on the neutron generator. It is expected that this work will be performed during 1977. The design and operation of the first prototype neutron generators is described

  8. Pulsed neutron generator

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bykovskii, Yu.A.; Vergun, I.I.; Kozlovskii, K.I.; Kozyrev, Yu.P.; Leonov, R.K.; Simagin, B.I.; Tsybin, A.S.; Shikanov, A.Ie.

    1986-03-01

    The paper describes a new device for generating pulsed neutron fields, utilized in nuclear geophysics for carrying out pulsed neutron logging and activation analysis under field conditions. The invention employs a sealed-off neutron tube with a laser ion source which increases neutron yield to the level of 10 neutrons per second or higher. 2 refs., 1 fig

  9. Neutron generator control system

    International Nuclear Information System (INIS)

    Peelman, H.E.; Bridges, J.R.

    1981-01-01

    A method is described of controlling the neutron output of a neutron generator tube used in neutron well logging. The system operates by monitoring the target beam current and comparing a function of this current with a reference voltage level to develop a control signal used in a series regulator to control the replenisher current of the neutron generator tube. (U.K.)

  10. Calculation of prompt neutron spectra for curium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1997-03-01

    With the aim of checking the existing evaluations contained in JENDL-3.2 and providing new evaluations based on a methodology proposed by the author, a series of calculations of prompt neutron spectra have been undertaken for curium isotopes. Some of the evaluations in JENDL-3.2 was found to be unphysically hard and should be revised. (author)

  11. Prompt gamma cold neutron activation analysis applied to biological materials

    International Nuclear Information System (INIS)

    Rossbach, M.; Hiep, N.T.

    1992-01-01

    Cold neutrons at the external neutron guide laboratory (ELLA) of the KFA Juelich are used to demonstrate their profitable application for multielement characterization of biological materials. The set-up and experimental conditions of the Prompt Gamma Cold Neutron Activation Analysis (PGCNAA) device is described in detail. Results for C, H, N, S, K, B, and Cd using synthetic standards and the 'ratio' technique for calculation are reported for several reference materials and prove the method to be reliable and complementary with respect to the elements being determined by INAA. (orig.)

  12. Correction factor for the experimental prompt neutron decay constant

    International Nuclear Information System (INIS)

    Talamo, Alberto; Gohar, Y.; Sadovich, S.; Kiyavitskaya, H.; Bournos, V.; Fokov, Y.; Routkovskaya, C.

    2013-01-01

    Highlights: • Definition of a spatial correction factor for the experimental prompt neutron decay constant. • Introduction of a MCNP6 calculation methodology to simulate Rossi-alpha distribution for pulsed neutron sources. • Comparison of MCNP6 results with experimental data for count rate, Rossi-alpha, and Feynman-alpha distributions. • Improvement of the comparison between numerical and experimental results by taking into account the dead-time effect. - Abstract: This study introduces a new correction factor to obtain the experimental effective multiplication factor of subcritical assemblies by the point kinetics formulation. The correction factor is defined as the ratio between the MCNP6 prompt neutron decay constant obtained in criticality mode and the one obtained in source mode. The correction factor mainly takes into account the longer neutron lifetime in the reflector region and the effects of the external neutron source. For the YALINA Thermal facility, the comparison between the experimental and computational effective multiplication factors noticeably improves after the application of the correction factor. The accuracy of the MCNP6 computational model of the YALINA Thermal subcritical assembly has been verified by reproducing the neutron count rate, Rossi-α, and Feynman-α distributions obtained from the experimental data

  13. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron.

    Science.gov (United States)

    Fantidis, J G; Nicolaou, G E; Potolias, C; Vordos, N; Bandekas, D V

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources ( 241 Am/Be, 252 Cf, 241 Am/B, and DT neutron generator). Among the different systems the 252 Cf neutron based PGNAA system has the best performance.

  14. Group Representation of the Prompt Fission Neutron Spectrum of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Croft, S.; Miller, K. A. [Safeguards Science and Technology Group (N-1), Nuclear Nonproliferation Division, Los Alamos National Laboratory, Los Alamos(United States)

    2011-12-15

    We review the spectral representation used for the prompt fission neutron spectrum of 252Cf in the International Organization for Standardization document ISO 8529-1. We find corrections to Table A.2, the discrete group structure form, of this report are needed. We describe the approach to generating replacement values and provide a new tabulation.

  15. Nanosecond neutron generator

    International Nuclear Information System (INIS)

    Lobov, S.I.; Pavlovskaya, N.G.; Pukhov, S.P.

    1991-01-01

    High-voltage nanosecond neutron generator for obtaining neutrons in D-T reaction is described. Yield of 6x10 6 neutron/pulse was generated in a sealed gas-filled diode with a target on the cathode by accelerating pulse voltage of approximately 0.5 MV and length at half-height of 0.5 ns and deuterium pressure of 6x10 -2 Torr. Ways of increasing neutron yield and possibilities of creating generators of nanosecond neutron pulses with great service life are considered

  16. Compact neutron generators for environmental recovery applications

    International Nuclear Information System (INIS)

    Leung, K. N.; Firestone, R. B.; Lou, T. P.; Reijonen, J.; Vujic, J. Lj.

    2002-01-01

    New generations of compact neutron sources are being developed at the Lawrence Berkeley National Laboratory (LBNL). The D-D or D-T neutron generators can be used to perform precise elemental analysis by Prompt Gamma-Ray Activation Analysis (PGAA) in place of a nuclear reactor. The neutron generators will be composed of an ion source, from which a 1.5 A deuterium beam will be extracted and accelerated to about 150 keV onto a target loaded with deuterium. Based on the D-D nuclear reaction, the neutron generator will yield approximately 10 12 n/s (10 14 n/s for D-T reaction). With this neutron output, thermal and cold neutron fluxes of 10 7 n/s cm 2 and 6 x 10 6 n/s cm 2 have been estimated using neutron moderators designed by the neutron transport simulation code MCNP. (author)

  17. Determination of prompt neutron decay constant of the AP-600 reactor core

    International Nuclear Information System (INIS)

    Surbakti, T.

    1998-01-01

    Determination of prompt neutron decay constant of the AP-600 reactor core has been performed using combination of two codes WIMS/D4 and Batan-2DIFF. The calculation was done at beginning of cycle and all of control rods pulled out. Cell generation from various kinds of core materials was done with 4 neutron energy group in 1-D transport code (WIMS/D4). The cell is considered for 1/4 fuel assembly in cluster model with square pitch arrange and then, the dimension of its unit cell is calculated. The unit cell consist of a fuel and moderator unit. The unit cell dimension as input data of WIMS/D4 code, called it annulus, is obtained from the equivalent unit cell. Macroscopic cross sections as output was used as input on neutron diffusion code Batan-2DIFF for core calculation as appropriate with three enrichment regions of the fuel of AP-600 core, namely 2, 2.5, and 3%. From result of diffusion code ( Batan-2DIFF) is obtained the value of delayed neutron fraction of 6.932E-03 and average prompt neutron life-time of 26.38 μs, so that the value of prompt neutron decay constant is 262.8 s-1. If it is compared the calculation result with the design value, the deviation are, for the design value of delayed neutron fraction is 7.5E-03, about 8% and the design value of average prompt neutron life time is 19.6 μs, about 34% respectively. The deviation because there are still unknown several core components of AP-600, so it didn't include in calculation yet

  18. Status report on the development of a prompt fission neutron uranium borehole logging technique

    International Nuclear Information System (INIS)

    Smith, G.W.

    1977-05-01

    The prompt fission neutron (PFN) method of direct uranium measurement was studied. The PFN uranium logging technique measures the enhanced epithermal neutron population created by the prompt thermal fission of 235 U to assay uranium mineralization around a borehole. This neutron population exists for several hundred microseconds after a pulsed neutron source produces a burst of high energy (14 MeV) neutrons. A feasibility study established the basic relationship between the uranium concentration and the enhanced epithermal neutron count, and defined the major measurement perturbing factors. Following the feasibility study, development of a PFN prototype field probe was undertaken. A laboratory type neutron generator, the Controlatron, was modified for use in the probe. Field evaluation of the prototype system began in January 1976. Comparisons of neutron logs and natural gamma logs taken during this evaluation period clearly define many disequilibrium conditions as verified by ore grade estimates from core samples. The feasibility of the PFN logging technique to detect uranium in-situ has now been demonstrated

  19. The study of prompt neutron spectra of 238U fission induced by fast neutron

    International Nuclear Information System (INIS)

    Li Anli; Bai Xixiang; Wang Yufeng; Wang Xiaozhong; Men Jiangchen; Huang Shengnian

    1990-01-01

    The measurements of prompt neutron time-of-flight spectra of U fission induced by 11 MeV neutrons were carried out at HI-13 Tandem Van de Graaff Accelerator Laboratory in 1989. The block diagram of the electronics is shown. A fission neutron TOF spectrum for the sixth section of the fission plates and the left detector at low bias is given. The data accumulation time is 60 h

  20. Cylindrical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo [Hercules, CA

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  1. Compact neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  2. Prompt fission neutron spectra and anti νp

    International Nuclear Information System (INIS)

    Madland, D.G.

    Methods used to obtain the evaluated prompt fisson neutron spectrum N(E) and the average prompt neutron multiplicity anti ν/sub p/ are reviewed. The relative influence of experimental data; interpolated, extrapolated, and fitted experimental data; systematics; and nuclear theory are considered for the cases where (a) abundant experimental data exist, (b) some experimental data exist, and (c) no experimental data exist. The Maxwellian and Watt distributions, and the determination of the parameters of these distributions by data fitting, are described and compared to recent new theoretical work on the calculation of N(E). Similarly, various expressions for anti γ/sub p/ that have been obtained by data fitting and systematics are described and compared to recent new theoretical work. Complications in the evaluation of N(E) and anti γ/sub p/ due to the onset of multiple-chance fission and the interrelationships between N(E), anti γΔ/sub p/ and the multiple-chance fission cross section are discussed using the example of the fission of 235 U. Some statistics and comments are given on the evaluations of N(E) and anti γ/sub p/ contained in ENDF/B-V, and a number of concluding recommendations are made for future evaluation work

  3. Neutron capture prompt gamma-ray activation analysis at the NIST cold neutron research facility

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, R M; Zeisler, R; Vincent, D H; Greenberg, R R; Stone, C A; Mackey, E A [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Anderson, D L [Food and Drug Administration, Washington, DC (United States); Clark, D D [Cornell Univ., Ithaca, NY (United States)

    1993-01-01

    An instrument for neutron capture prompt gamma-ray activation analysis (PGAA) has been constructed as part of the Cold Neutron Research Facility at the 20 MW National Institute of Standards and Technology Research Reactor. The neutron fluence rate (thermal equivalent) is 1.5*10[sup 8] n*cm[sup -2]*s[sup -] [sup 1], with negligible fast neutrons and gamma-rays. With compact geometry and hydrogen-free construction, the sensitivity is sevenfold better than an existing thermal instrument. Hydrogen background is thirtyfold lower. (author) 17 refs.; 2 figs.

  4. Partial neutron capture cross sections of actinides using cold neutron prompt gamma activation analysis

    International Nuclear Information System (INIS)

    Genreith, Christoph

    2015-01-01

    Nuclear waste needs to be characterized for its safe handling and storage. In particular long-lived actinides render the waste characterization challenging. The results described in this thesis demonstrate that Prompt Gamma Neutron Activation Analysis (PGAA) with cold neutrons is a reliable tool for the non-destructive analysis of actinides. Nuclear data required for an accurate identification and quantification of actinides was acquired. Therefore, a sample design suitable for accurate and precise measurements of prompt γ-ray energies and partial cross sections of long-lived actinides at existing PGAA facilities was presented. Using the developed sample design the fundamental prompt γ-ray data on 237 Np, 241 Am and 242 Pu were measured. The data were validated by repetitive analysis of different samples at two individual irradiation and counting facilities - the BRR in Budapest and the FRM II in Garching near Munich. Employing cold neutrons, resonance neutron capture by low energetic resonances was avoided during the experiments. This is an improvement over older neutron activation based works at thermal reactor neutron energies. 152 prompt γ-rays of 237 Np were identified, as well as 19 of 241 Am, and 127 prompt γ-rays of 242 Pu. In all cases, both high and lower energetic prompt γ-rays were identified. The most intense line of 237 Np was observed at an energy of E γ =182.82(10) keV associated with a partial capture cross section of σ γ =22.06(39) b. The most intense prompt γ-ray lines of 241 Am and of 242 Pu were observed at E γ =154.72(7) keV with σ γ =72.80(252) b and E γ =287.69(8) keV with σ γ =7.07(12) b, respectively. The measurements described in this thesis provide the first reported quantifications on partial radiative capture cross sections for 237 Np, 241 Am and 242 Pu measured simultaneously over the large energy range from 45 keV to 12 MeV. Detailed uncertainty assessments were performed and the validity of the given uncertainties was

  5. Effective delayed neutron fraction and prompt neutron lifetime of Tehran research reactor mixed-core

    International Nuclear Information System (INIS)

    Lashkari, A.; Khalafi, H.; Kazeminejad, H.

    2013-01-01

    Highlights: ► Kinetic parameters of Tehran research reactor mixed-core have been calculated. ► Burn-up effect on TRR kinetics parameters has been studied. ► Replacement of LEU-CFE with HEU-CFE in the TRR core has been investigated. ► Results of each mixed core were compared to the reference core. ► Calculation of kinetic parameters are necessary for reactivity and power excursion transient analysis. - Abstract: In this work, kinetic parameters of Tehran research reactor (TRR) mixed cores have been calculated. The mixed core configurations are made by replacement of the low enriched uranium control fuel elements with highly enriched uranium control fuel elements in the reference core. The MTR P C package, a nuclear reactor analysis tool, is used to perform the analysis. Simulations were carried out to compute effective delayed neutron fraction and prompt neutron lifetime. Calculation of kinetic parameters is necessary for reactivity and power excursion transient analysis. The results of this research show that effective delayed neutron fraction decreases and prompt neutron lifetime increases with the fuels burn-up. Also, by increasing the number of highly enriched uranium control fuel elements in the reference core, the prompt neutron lifetime increases, but effective delayed neutron fraction does not show any considerable change

  6. Differential and integral characteristics of prompt fission neutrons in the statistical theory

    International Nuclear Information System (INIS)

    Gerasimenko, B.F.; Rubchenya, V.A.

    1989-01-01

    Hauser-Feshbach statistical theory is the most consistent approach to the calculation of both spectra and prompt fission neutrons characteristics. On the basis of this approach a statistical model for calculation of differential prompt fission neutrons characteristics of low energy fission has been proposed and improved in order to take into account the anisotropy effects arising at prompt fission neutrons emission from fragments. 37 refs, 6 figs

  7. Theoretical description of prompt neutron multiplicity and spectra

    International Nuclear Information System (INIS)

    Manailescu, C.

    2013-02-01

    The present work concerns two of successful models used today: PbP (Point by Point) and the Monte-Carlo approaches for providing all quantities characterizing the prompt neutron and gamma-ray emission. Therefore the thesis is structured as described below. The description of the PbP model and of the extended Los Alamos model for higher energies that takes into account the secondary chains and ways is given in Chapter II. In this chapter are detailed also examples of PbP and most probable fragmentation approach calculations for various quantities which characterize prompt emission: multi-parametric matrices [meaning different quantities as a function of fragment and of TKE (Total Kinetic Energy of the fission fragments)], quantities as a function of fragment mass, quantities as a function of the TKE and total average quantities, for different spontaneous and neutron induced fissioning systems. Special care was given to the TXE (Total Excitation Energy) partition between the fully accelerated fission fragments, two partition methods used in the PbP model being discussed in details. In Chapter III is given the description of the Monte Carlo treatment included in the FIFRELIN code. Only those aspects that differ from the PbP treatment are emphasized, namely the treatment of the moment of inertia entering the rotational energy calculation and the TXE partition method based on a mass dependent temperature ratio law. A special attention is given to the latest developments of the code concerning the inclusion of the energy dependent compound nucleus cross-section of the inverse process of neutron evaporation from fragments. In this chapter examples of calculation with the FIFRELIN code for the case of the standard fissioning system 252 Cf (SF) are given. Original results for several plutonium spontaneous fissioning systems ( 236,238,240,242,244 Pu) and one neutron induced fissioning system ( 239 Pu(nth,f)) obtained with both PbP and Monte-Carlo treatments are given in

  8. Utilisation of prompt fission neutron technology in Greenfields uranium exploration

    International Nuclear Information System (INIS)

    Mutz, P.R.

    2007-01-01

    Conventionally, gamma detection technology has been used in uranium exploration programs for the initial detection of uranium as well as for a determination of uranium concentration. Geophysical logging companies use wireline gamma probes to measure uranium within boreholes, and field technicians utilise hand held gamma meters to detect uranium in rock samples, drill cuttings and cores. Borehole geophysical logging equipment typically records the uranium concentration as %eU 3 O8, where e represents an equivalent determination of uranium concentration as opposed to a laboratory assay. This method of uranium determination is an indirect method, as it measures gamma radiation from uranium-238 (U-238) isotope decay chain progeny; principally the bismuth-214 (Bi-214) isotope. Consequently, the uranium determination can be inaccurate due to natural disequilibrium between the U-238 parent and the decay chain progeny. This is especially true in sedimentary hosted uranium deposits, where the uranium and daughter progeny may have been geochemically separated. The gamma detection method for uranium can also be rendered inaccurate by detecting the gamma signature from potassium in clays as well as from thorium; both of which can provide a false (enhanced) eU 3 O8 determination. Prompt Fission Neutron (PFN) technology is a geophysical wireline logging technology used in the same manner as conventional gamma logging. The difference is that PFN provides a direct determination of uranium within a borehole, irrespective of natural disequilibrium or the presence of other radioactive elements. This paper provides a brief description of natural uranium and radioactivity as a basis for explaining the conventional use of gamma radiation detectors for the detection and determination of uranium concentration in exploration boreholes, including the potential pitfalls of this technology. A detailed description of prompt fission neutron technology is also presented, along with a discussion

  9. High energy neutron generator

    International Nuclear Information System (INIS)

    Barjon, R.; Breynat, G.

    1987-01-01

    This patent describes a generator of fast neutrons only slightly contaminated by neutrons of energy less than 15 MeV, comprising a source of charged particles of energy equal to at least 15 MeV, a target made of lithium deuteride, and means for cooling the target. The target comprises at least two elements placed in series in the path of the charged particles and separated from each other, the thickness of each of the elements being selected as a function of the average energy of the charged particles emitted from the source and the energy of the fast neutrons to be generated such that neutrons of energy equal to at least 15 MeV are emitted in the forward direction in response to the bombardment of the target from behind by the charged particles. The target cooling means comprises means for circulating between and around the elements a gas which does not chemically react with lithium deuteride

  10. The intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1966-07-01

    The presentation discusses both the economic and research contexts that would be served by producing neutrons in gram quantities at high intensities by electrical means without uranium-235. The revenue from producing radioisotopes is attractive. The array of techniques introduced by the multipurpose 65 megawatt Intense Neutron Generator project includes liquid metal cooling, superconducting magnets for beam bending and focussing, super-conductors for low-loss high-power radiofrequency systems, efficient devices for producing radiofrequency power, plasma physics developments for producing and accelerating hydrogen, ions at high intensity that are still far out from established practice, a multimegawatt high voltage D.C. generating machine that could have several applications. The research fields served relate principally to materials science through neutron-phonon and other quantum interactions as well as through neutron diffraction. Nuclear physics is served through {mu}-, {pi}- and K-meson production. Isotope production enters many fields of applied research. (author)

  11. The intense neutron generator

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1966-01-01

    The presentation discusses both the economic and research contexts that would be served by producing neutrons in gram quantities at high intensities by electrical means without uranium-235. The revenue from producing radioisotopes is attractive. The array of techniques introduced by the multipurpose 65 megawatt Intense Neutron Generator project includes liquid metal cooling, superconducting magnets for beam bending and focussing, super-conductors for low-loss high-power radiofrequency systems, efficient devices for producing radiofrequency power, plasma physics developments for producing and accelerating hydrogen, ions at high intensity that are still far out from established practice, a multimegawatt high voltage D.C. generating machine that could have several applications. The research fields served relate principally to materials science through neutron-phonon and other quantum interactions as well as through neutron diffraction. Nuclear physics is served through μ-, π- and K-meson production. Isotope production enters many fields of applied research. (author)

  12. {sup 235}U(n,F) prompt fission neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, M.V.; Tetereva, N.A. [Joint Institute of Nuclear and Energy Research, Minsk-Sosny (Belarus); Pronyaev, V.P.; Kagalenko, A.B. [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Capote, R. [International Atomic Energy Agency, Vienna (Austria); Granier, T.; Morillon, B. [CEA, Centre DAM-IIe de France, 91 - Arpajon (France); Hambsch, F.J. [EC-JRC Institute for Reference Materials and Measurements, Geel (Belgium); Sublet, J.C. [CEA Cadarache, 13 - Saint Paul lez Durance (France)

    2009-07-01

    The longstanding problem of inconsistency of integral thermal data testing and differential prompt fission neutron spectra data (PFNS) is mostly due to rather poor fits of differential PFNS data in major data libraries. The measured database is updated by using modern standards including Manhart's evaluation of the spontaneous fission neutron spectra of {sup 252}Cf(sf). That largely removes the inconsistency of older thermal neutron-induced PFNS measurements with newest data of JRC IRMM by Hambsch et al. (2009). A phenomenological approach, developed by Kornilov et al. (1999), for the first-chance fission and extended for the emissive fission domain by Maslov et al. (2005) is calibrated at E{sub th} to predict both the PFNS average energy and PFNS shape up to 20 MeV. The latter is extremely important, since rather close values in fact correspond to quite discrepant spectra shapes, which influences reactor neutronics strongly. The proposed phenomenological representation of the PFNS reproduces both soft and hard energy tails of {sup 235}U(n{sub th},F) PFNS at thermal incident neutron energy E{sub th}. In the first-chance and emissive fission domain evaluated PFNS are consistent with the data by Ethvignot et al. (2005). A compiled MF=5 Endf/B-formatted file of the {sup 235}U(n,F) PFNS largely removes the inconsistencies of the evaluated differential PFNS with integral data benchmarks. Almost perfect fits are attained for available differential PFNS data from E{sub th} up to E{sub n}=14.7 MeV, with few exceptions at E{sub n}=2.9 and E{sub n}=5 MeV. Fast integral critical experiment like GODIVA or Flattop benchmarks might be reproduced almost with the same accuracy as with the PFNS of the major data libraries. That reveals a rather delicate compensation effect, since present and previous PFNS shapes are drastically different from each other. Thermal assemblies benchmarking reveals positive biases in k(eff), which might be attributed to the influence of

  13. Using anisotropies in prompt fission neutron coincidences to assess the neutron multiplication of highly multiplying subcritical plutonium assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.M., E-mail: jonathan_mueller@ncsu.edu; Mattingly, J.

    2016-07-21

    There is a significant and well-known anisotropy between the prompt neutrons emitted from a single fission event; these neutrons are most likely to be observed at angles near 0° or 180° relative to each other. However, the propagation of this anisotropy through different generations of a fission chain reaction has not been previously studied. We have measured this anisotropy in neutron–neutron coincidences from a subcritical highly-multiplying assembly of plutonium metal. The assembly was a 4.5 kg α-phase plutonium metal sphere composed of 94% {sup 239}Pu and 6% {sup 240}Pu by mass. Data were collected using two EJ-309 liquid scintillators and two EJ-299 plastic scintillators. The angular distribution of neutron–neutron coincidences was measured at 90° and 180° and found to be largely isotropic. Simulations were performed using MCNPX-PoliMi of similar plutonium metal spheres of varying sizes and a correlation between the neutron multiplication of the assembly and the anisotropy of neutron–neutron coincidences was observed. In principle, this correlation could be used to assess the neutron multiplication of an unknown assembly.

  14. Spherical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo

    2006-11-21

    A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

  15. Recent improvements in the calculation of prompt fission neutron spectra: Preliminary results

    International Nuclear Information System (INIS)

    Madland, D.G.; LaBauve, R.J.; Nix, J.R.

    1989-01-01

    We consider three topics in the refinement and improvement of our original calculations of prompt fission neutron spectra. These are an improved calculation of the prompt fission neutron spectrum N(E) from the spontaneous fission of 252 Cf, a complete calculation of the prompt fission neutron spectrum matrix N(E,E n ) from the neutron-induced fission of 235 U, at incident neutron energies ranging from 0 to 15 MeV, and an assessment of the scission neutron component of the prompt fission neutron spectrum. Preliminary results will be presented and compared with experimental measurements and an evaluation. A suggestion is made for new integral cross section measurements. (author). 45 refs, 12 figs, 1 tab

  16. Systematic evaluation of prompt neutron spectra in fission

    International Nuclear Information System (INIS)

    Osawa, Takaaki

    1995-01-01

    To create the nuclear data fail JEND-32, the prompt fission neutron spectra X(E) of 233 U, 235 U, 238 U and 239 Pu were reevaluated and some improvement were added to the calculation models. We tried to extend the calculation method of fission spectra of nuclides with poor measurement data in consideration of increasing the importance of nuclear data of minor actinoids. We improved and extended the following five points. (1) On JENDL-3.1, the fission spectra of principal fissible materials had been calculated by the Modland-Nix model which the neutron emissions of fragments were calculated under the approximation of the constant inverse process cross section. In the paper, the spectra were calculated by the use of the inverse process cross section depend on the energy obtained by the calculation of the optical model. The result showed the increase of low energy components and the softening effect of spectra (2) On JENDL-3.1, the all fission processes were assumed to undergo (n,f) reaction. In the paper, they were calculated by the multi-chance fission such as (n, n'f), (n, 2nf) and (n, 3nf) etc. Softening of the spectra (En > 6 MeV) was obtained by this method. (3) The level density parameter (LDP) has been assumed as a = A/C in either case of light fragment (LF) and heavy fragment (HF) in the original Madland-Nix model. But we used LDP based on the Ignatyuk model under consideration of the shell effects of nuclear fragments, hence the neutron spectra of heavy fragments were hardening. (4) Nuclear temperature of both fragments had been assumed to be the same at original model, but now R T = Tm/TmH was derived to calculate them. The ratio of middle/both side components of spectra was changed. (5) Unknown neutron fission spectra of minor actinide were able to the assumed on the basis of Moriyama-Ohnishi model. (S.Y.)

  17. Summary Report of Second Research Coordination Meeting on Prompt Fission Neutron Spectra of Major Actinides

    International Nuclear Information System (INIS)

    Capote Noy, R.

    2013-09-01

    A summary is given of the Second Research Coordination Meeting on Prompt Fission Neutron Spectra of Actinides. Experimental data and modelling methods on prompt fission neutron spectra were reviewed. Extensive technical discussions held on theoretical methods to calculate prompt fission spectra. Detailed coordinated research proposals have been agreed. Summary reports of selected technical presentations at the meeting are given. The resulting work plan of the Coordinated Research Programme is summarized, along with actions and deadlines. (author)

  18. High Intensity, Pulsed, D-D Neutron Generator

    International Nuclear Information System (INIS)

    Williams, D.L.; Vainionpaa, J.H.; Jones, G.; Piestrup, M.A.; Gary, C.K.; Harris, J.L.; Fuller, M.J.; Cremer, J.T.; Ludewigt, Bernhard A.; Kwan, J.W.; Reijonen, J.; Leung, K.-N.; Gough, R.A.

    2008-01-01

    Single ion-beam RF-plasma neutron generators are presented as a laboratory source of intense neutrons. The continuous and pulsed operations of such a neutron generator using the deuterium-deuterium fusion reaction are reported. The neutron beam can be pulsed by switching the RF plasma and/or a gate electrode. These generators are actively vacuum pumped so that a continuous supply of deuterium gas is present for the production of ions and neutrons. This contributes to the generator's long life. These single-beam generators are capable of producing up to 1E10 n/s. Previously, Adelphi and LBNL have demonstrated these generators applications in fast neutron radiography, Prompt Gamma Neutron Activation Analysis (PGNAA) and Neutron Activation Analysis (NAA). Together with an inexpensive compact moderator, these high-output neutron generators extend useful applications to home laboratory operations.

  19. Neutron generation in lightning bolts

    International Nuclear Information System (INIS)

    Shah, G.N.; Razdan, H.; Bhat, C.L.; Ali, Q.M.

    1985-01-01

    To ascertain neutron generation in lightning bolts, the authors have searched for neutrons from individual lightning strokes, for a time-interval comparable with the duration of the lightning stroke. 10 7 -10 10 neutrons per stroke were found, thus providing the first experimental evidence that neutrons are generated in lightning discharges. (U.K.)

  20. Coal stream composition analysis for process control using prompt neutron activation analysis

    International Nuclear Information System (INIS)

    Gozani, T.; Reynolds, G.; Elias, E.; Maung, T.; Bozorgmanesh, H.; Orphan, V.

    1977-01-01

    In this paper we describe early results of a series of laboratory experiments and computer modeling studies designed to provide realistic accuracy limits for the determination of the elemental concentration in coal using prompt neutron activation analysis. The results provide guidance for optimizing the technique for monitoring the quality of coal which is being input to an electric power generating plant. The reported work was performed as the initial phase of an ongoing program to develop a prototype on-line coal analyzer based on the PNAA technique for power plant application

  1. Neutron sensitivity of prompt-response self-powered neutron detectors and the interval rule

    International Nuclear Information System (INIS)

    Molina Avila, J.; Carmolopes, M.

    1989-01-01

    This paper is devoted to the calculation of thermal s th and epithermal s epi sensitivities of cobalt prompt-response Self-Powered Neutron Detectors (SPNDs). The thermal sensitivity was obtained for a Maxwellian neutron field, and the effect of scattering on the self-shielding correction was taken into consideration in the second-collision approximation. The dependence of s th on the emitter radius R was studied in a wide region of R (0.025 to 0.2 cm). The differential and global epithermal sensitivities were calculated using a simple expression for the first-collision neutron absorption probability. Finally, a criterion to evaluate the accuracy of the parameters of the model was established in the form of some Interval Rule which is very sensitive to the radial dependence of the flux perturbation correction and other parameters of the model in both the thermal and epithermal regions

  2. Consultants' meeting on prompt fission neutron spectra of major actinides. Summary report

    International Nuclear Information System (INIS)

    Capote Noy, R.; Maslov, V.; Bauge, E.; Ohsawa, T.; Vorobyev, A.; Chadwick, M.B.; Oberstedt, S.

    2009-01-01

    A Consultants' Meeting on 'Prompt Fission Neutron Spectra of Major Actinides' was held at IAEA Headquarters, Vienna, Austria, to discuss the adequacy and quality of the recommended prompt fission neutron spectra to be found in existing nuclear data applications libraries. These prompt fission neutron spectra were judged to be inadequate, and this problem has proved difficult to resolve by means of theoretical modelling. Major adjustments may be required to ensure the validity of such important data. There is a strong requirement for an international effort to explore and resolve these difficulties and recommend prompt fission neutron spectra and uncertainty covariance matrices for the actinides over the neutron energy range from thermal to 20 MeV. Participants also stressed that there would be a strong need for validation of the resulting data against integral critical assembly and dosimetry data. (author)

  3. Short pulse neutron generator

    Science.gov (United States)

    Elizondo-Decanini, Juan M.

    2016-08-02

    Short pulse neutron generators are described herein. In a general embodiment, the short pulse neutron generator includes a Blumlein structure. The Blumlein structure includes a first conductive plate, a second conductive plate, a third conductive plate, at least one of an inductor or a resistor, a switch, and a dielectric material. The first conductive plate is positioned relative to the second conductive plate such that a gap separates these plates. A vacuum chamber is positioned in the gap, and an ion source is positioned to emit ions in the vacuum chamber. The third conductive plate is electrically grounded, and the switch is operable to electrically connect and disconnect the second conductive plate and the third conductive plate. The at least one of the resistor or the inductor is coupled to the first conductive plate and the second conductive plate.

  4. Prompt neutron spectrum of the spontaneous fission of californium-252

    International Nuclear Information System (INIS)

    Zamyatnin, Yu.S.; Kroshkin, N.I.; Korostylev, V.A.; Nefedov, V.N.; Ryazanov, D.K.; Starostov, B.I.; Semenov, A.F.

    1976-01-01

    The californium-252 spontaneous fission neutron spectrum was measured in the energy range of 0.01 to 10 MeV by the time-of-flight technique using various neutron detectors. The measurements of 252 Cf neutron spectrum at energies of 0.01 to 5 MeV were performed as a function of fission fragment kinetic energy. The mean neutron spectrum energy in the range of 0.7 to 10 MeV was found from the results of measurements. The irregularity in the 252 Cf neutron spectrum in the neutron energy range of less than 0.7 MeV compared to theoretical values is discussed. The mechanism of 252 Cf neutron emission is also discussed on the basis of neutron yield angle measurements. 12 references

  5. Prompt γ-ray data evaluation of thermal-neutron capture for A = 1-25

    International Nuclear Information System (INIS)

    Zhou Chunmei

    1999-01-01

    The method of prompt γ-ray data evaluation for thermal-neutron capture has been briefly presented. The prompt capture γ-ray data of stable nuclei for A = 1 - 25 are evaluated. The evaluated data have been changed into the ENSDF format and the checks of physics and format have been made

  6. Prompt gamma ray diagnostics and enhanced hadron-therapy using neutron-free nuclear reactions

    Science.gov (United States)

    Giuffrida, L.; Margarone, D.; Cirrone, G. A. P.; Picciotto, A.; Cuttone, G.; Korn, G.

    2016-10-01

    We propose a series of simulations about the potential use of Boron isotopes to trigger neutron-free (aneutronic) nuclear reactions in cancer cells through the interaction with an incoming energetic proton beam, thus resulting in the emission of characteristic prompt gamma radiation (429 keV, 718 keV and 1435 keV). Furthermore assuming that the Boron isotopes are absorbed in cancer cells, the three alpha-particles produced in each p-11B aneutronic nuclear fusion reactions can potentially result in the enhancement of the biological dose absorbed in the tumor region since these multi-MeV alpha-particles are stopped inside the single cancer cell, thus allowing to spare the surrounding tissues. Although a similar approach based on the use of 11B nuclei has been proposed in [Yoon et al. Applied Physics Letters 105, 223507 (2014)], our work demonstrate, using Monte Carlo simulations, the crucial importance of the use of 10B nuclei (in a solution containing also 11B) for the generation of prompt gamma-rays, which can be applied to medical imaging. In fact, we demonstrate that the use of 10B nuclei can enhance the intensity of the 718 keV gamma-ray peak more than 30 times compared to the solution containing only 11B nuclei. A detailed explanation of the origin of the different prompt gamma-rays, as well as of their application as real-time diagnostics during a potential cancer treatment, is here discussed.

  7. Facility at CIRUS reactor for thermal neutron induced prompt γ-ray spectroscopic studies

    International Nuclear Information System (INIS)

    Biswas, D.C.; Danu, L.S.; Mukhopadhyay, S.; Kinage, L.A.; Prashanth, P.N.; Goswami, A.; Sahu, A.K.; Shaikh, A.M.; Chatterjee, A.; Choudhury, R.K.; Kailas, S.

    2013-01-01

    A facility for prompt γ-ray spectroscopic studies using thermal neutrons from a radial beam line of Canada India Research Utility Services (CIRUS) reactor, Bhabha Atomic Research Centre (BARC), has been developed. To carry out on-line spectroscopy experiments, two clover germanium detectors were used for the measurement of prompt γ rays. For the first time, the prompt γ–γ coincidence technique has been used to study the thermal neutron induced fission fragment spectroscopy (FFS) in 235 U(n th , f). Using this facility, experiments have also been carried out for on-line γ-ray spectroscopic studies in 113 Cd(n th , γ) reaction

  8. Body composition to climate change studies - the many facets of neutron induced prompt gamma-ray analysis

    International Nuclear Information System (INIS)

    Mitra, S.

    2008-01-01

    In-vivo body composition analysis of humans and animals and in-situ analysis of soil using fast neutron inelastic scattering and thermal neutron capture induced prompt-gamma rays have been described. By measuring carbon (C), nitrogen (N) and oxygen (O), protein, fat and water are determined. C determination in soil has become important for understanding below ground carbon sequestration process in the light of climate change studies. Various neutron sources ranging from radio isotopic to compact 14 MeV neutron generators employing the associated particle neutron time-of-flight technique or micro-second pulsing were implemented. Gamma spectroscopy using recently developed digital multi-channel analyzers has also been described

  9. Body composition to climate change studies - the many facets of neutron induced prompt gamma-ray analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mitra,S.

    2008-11-17

    In-vivo body composition analysis of humans and animals and in-situ analysis of soil using fast neutron inelastic scattering and thermal neutron capture induced prompt-gamma rays have been described. By measuring carbon (C), nitrogen (N) and oxygen (O), protein, fat and water are determined. C determination in soil has become important for understanding below ground carbon sequestration process in the light of climate change studies. Various neutron sources ranging from radio isotopic to compact 14 MeV neutron generators employing the associated particle neutron time-of-flight technique or micro-second pulsing were implemented. Gamma spectroscopy using recently developed digital multi-channel analyzers has also been described.

  10. Prompt neutron energy spectrum for the spontaneous fission of Cf-252

    International Nuclear Information System (INIS)

    Blinov, M.V.; Boykov, G.S.; Vitenko, V.A.

    1985-06-01

    The prompt neutron spectrum for the spontaneous fission of Cf-252 has been measured in 0.01-10 MeV region by the time-of-flight technique using a fast ionization chamber with U-235 layers as the neutron detector. Numerical data for the spectrum are presented, with an error file. (author)

  11. An evaluation of the spontaneous fission prompt neutron spectrum of 252Cf

    International Nuclear Information System (INIS)

    Bojkov, G.S.; Yurevich, V.I.

    1987-01-01

    An evaluation of the spontaneous fission prompt neutron spectrum of 252 Cf from 1 keV to 20 MeV is described. Variance-covariance matrices for a number of recent experimental data sets were constructed and used to evaluate the neutron spectrum following a Bayesian procedure. The evaluated spectrum is compared with various experimental and theoretical representations. (author)

  12. Use of prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2015-06-11

    The possibility of using measured prompt gamma emissions from polyethylene to estimate neutron ambient dose equivalent is explored theoretically. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of a high density polyethylene cylinder to emit prompt gammas from interaction of neutrons with the nuclei of hydrogen and carbon present in polyethylene. The neutron energy dependent responses of hydrogen and carbon nuclei are combined appropriately to match the energy dependent neutron fluence to ambient dose equivalent conversion coefficients. The proposed method is tested initially with simulated spectra and then validated using experimental measurements with an Am–Be neutron source. Experimental measurements and theoretical simulations have established the feasibility of estimating neutron ambient dose equivalent using measured neutron induced prompt gammas emitted from polyethylene with an overestimation of neutron dose at very low energies. - Highlights: • A new method for estimating H{sup ⁎}(10) using prompt gamma emissions from HDPE. • Linear combination of 2.2 MeV and 4.4 MeV gamma intensities approximates DCC (ICRP). • Feasibility of the method was established theoretically and experimentally. • The response of the present technique is very similar to that of the rem meters.

  13. Evaluation of secondary and prompt fission neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Porodzinskij, Yu.V.; Sukhovitskij, E.Sh. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    A simple model allowing to split neutron emission spectra into reaction partials is suggested. Predicted spectra of (n,n`{gamma}), (n,n`f), etc appear to be much harder than usually evaluated. (author)

  14. Measurements of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections for 238U and 232Th

    International Nuclear Information System (INIS)

    Baba, Mamoru; Itoh, Nobuo; Maeda, Kazuto; Hirakawa, Naohiro; Wakabayashi, Hidetaka.

    1989-10-01

    This report presents the summary of experimental studies of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections of 238 U and 232 Th. The experiments were performed at Tohoku University Fast Neutron Laboratory employing a time-of-flight technique and Dynamitron accelerator as the pulsed neutron generator. From the experiments, we obtained the following data for both nuclei; 1. prompt fission neutron spectrum for 2 MeV neutrons, 2. double-differential neutron inelastic-scattering cross sections for 1.2, 2.0, 4.2, 6.1 and 14.1 MeV incident neutrons. Both in experiments and data processing, cares were taken to obtain reliable data by avoiding systematic uncertainty. The experimental data were compared with those by other experiments, evaluations and model calculations. Through the data comparison, some fundamental problems were found in the experiments by previous authors and the evaluations. The present data will provide useful data base for refinement of the evaluated data and theoretical models. (author)

  15. Uranium borehole logging using delayed or prompt fission neutrons

    International Nuclear Information System (INIS)

    Schulze, G.; Wuerz, H.

    1977-04-01

    The measurement of induced fission neutrons using Cf 252 and 14 MeV neutrons is a sensitive method for an in situ determination of Uranium. Applying this methods requires a unique relation between concentration of Uranium and intensity of induced fission neutrons. A discussion of parameters influencing the determination of concentration is given. A simple method is developed allowing an elemination of the geochemistry of the deposit and of the borehole configuration. Borehole probes using the methods described are of considerable help during the phase of detailed exploration of uranium ore deposits. These on-line tools allow an immediate determination of concentration. Thus avoiding the expensive and time consuming step of core drilling and subsequent chemical analysis. (orig./HP) [de

  16. Simulation of Neutron-Induced Prompt Gamma-ray Spectra Emitted from Fake Tungsten Gold Bar

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. M.; Sum, G. M. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Fake gold bars on the market cannot be identified easily without testing because they have the same appearance as a pure gold bar. A non-destructive monitoring method is needed to avoid the trading of fake gold bars on the market. The ultimate goal of this study is to find a fake gold bar detection method using a PGAA (Prompt Gamma Activation Analysis). Using existing data, the number of neutron capture for gold and tungsten in fake tungsten gold bar was calculated and a Monte Carlo simulation for the prompt neutron-induced gamma-ray spectra was conducted. A simulation for neutron-induced prompt gamma-rays spectra when a neutron beam is irradiated onto pure and fake gold bars was successfully conducted. Through a comparison between the prompt gamma-ray spectra of the pure gold bar and those of the fake gold bar, it was concluded that the observation of prompt high-energy gamma-rays from tungsten or a reduction of prompt gamma-rays from gold can be evidence of a fake gold bar. The possibility for detecting a fake gold bar using a PGAA facility was verified.

  17. Simulation of Neutron-Induced Prompt Gamma-ray Spectra Emitted from Fake Tungsten Gold Bar

    International Nuclear Information System (INIS)

    Lee, K. M.; Sum, G. M.

    2016-01-01

    Fake gold bars on the market cannot be identified easily without testing because they have the same appearance as a pure gold bar. A non-destructive monitoring method is needed to avoid the trading of fake gold bars on the market. The ultimate goal of this study is to find a fake gold bar detection method using a PGAA (Prompt Gamma Activation Analysis). Using existing data, the number of neutron capture for gold and tungsten in fake tungsten gold bar was calculated and a Monte Carlo simulation for the prompt neutron-induced gamma-ray spectra was conducted. A simulation for neutron-induced prompt gamma-rays spectra when a neutron beam is irradiated onto pure and fake gold bars was successfully conducted. Through a comparison between the prompt gamma-ray spectra of the pure gold bar and those of the fake gold bar, it was concluded that the observation of prompt high-energy gamma-rays from tungsten or a reduction of prompt gamma-rays from gold can be evidence of a fake gold bar. The possibility for detecting a fake gold bar using a PGAA facility was verified

  18. A compact mobile neutron generator

    International Nuclear Information System (INIS)

    Zhou Changgeng; Li Yan; Hu Yonghong; Lou Benchao; Wu Chunlei

    2007-06-01

    Through fitting the high voltage terminal from introducing overseas and pulse system et al. from oneself developing together, a compact mobile neutron generator is established. The length and weight of this neutron generator are 2 500 mm and less than 1 t, respectively. It can be expediently moved to the location which is required by experimental people. It is consisted of RF ion source, acceleration tube, high voltage generator, focus device, microsecond pulse system, gas leak system, control system, vacuum system and experimental target. It can produce 150 μA continuous deuterium ion beam current, also can produce the pulse deuterium ion beam current. The pulse widths are 10-100 μs and frequencies 10 Hz, 1 000 Hz, 10 000 Hz. The D-T neutron yields of the neutron generator may arrive 1.5 x 10 10 s -1 . The working principle and the structure of the main parts of this neutron generator are described. (authors)

  19. The 235U prompt fission neutron spectrum measured by the Chi-Nu project at LANSCE

    Directory of Open Access Journals (Sweden)

    Gomez J.A.

    2017-01-01

    Full Text Available The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum for the major actinides. At the Los Alamos Neutron Science Center (LANSCE, fission can be induced with neutrons ranging from 0.7 MeV and above. Using a two arm time-of-flight (TOF technique, the fission neutrons are measured in one of two arrays: a 22-6Li glass array for lower energies, or a 54-liquid scintillator array for outgoing energies of 0.5 MeV and greater. Presented here are the collaboration's preliminary efforts at measuring the 235U PFNS.

  20. Technical Aspect for Operating Portable Prompt Gamma Neutron Activation Analysis (PGNAA) on Terengganu Inscribed Stone

    International Nuclear Information System (INIS)

    Rasif Mohd Zain; Hearie Hassan; Roslan Yahya

    2015-01-01

    Prompt Gamma Neutron Activation analysis (PGNAA) is a type of neutron activation analysis which can determined element with nearly no gamma ray decay after being irradiated by neutron sourced. Thus, element that cannot be determined by the conventional NAA for example H, B, N, Si and Cd, can be determine by PGNAA. This paper focuses on the technical working procedure for operating portable PGNAA in field work. The device is designed as a portable non-destructive investigation tool applying an isotopic neutron source (Cf-252) and a gamma-ray spectroscopy system for in-situ investigation. The studied have been carried out on Terengganu inscribed stone at Terengganu State Museum. (author)

  1. 239Pu prompt fission neutron spectra impact on a set of criticality and experimental reactor benchmarks

    International Nuclear Information System (INIS)

    Peneliau, Y.; Litaize, O.; Archier, P.; De Saint Jean, C.

    2014-01-01

    A large set of nuclear data are investigated to improve the calculation predictions of the new neutron transport simulation codes. With the next generation of nuclear power plants (GEN IV projects), one expects to reduce the calculated uncertainties which are mainly coming from nuclear data and are still very important, before taking into account integral information in the adjustment process. In France, future nuclear power plant concepts will probably use MOX fuel, either in Sodium Fast Reactors or in Gas Cooled Fast Reactors. Consequently, the knowledge of 239 Pu cross sections and other nuclear data is crucial issue in order to reduce these sources of uncertainty. The Prompt Fission Neutron Spectra (PFNS) for 239 Pu are part of these relevant data (an IAEA working group is even dedicated to PFNS) and the work presented here deals with this particular topic. The main international data files (i.e. JEFF-3.1.1, ENDF/B-VII.0, JENDL-4.0, BRC-2009) have been considered and compared with two different spectra, coming from the works of Maslov and Kornilov respectively. The spectra are first compared by calculating their mathematical moments in order to characterize them. Then, a reference calculation using the whole JEFF-3.1.1 evaluation file is performed and compared with another calculation performed with a new evaluation file, in which the data block containing the fission spectra (MF=5, MT=18) is replaced by the investigated spectra (one for each evaluation). A set of benchmarks is used to analyze the effects of PFNS, covering criticality cases and mock-up cases in various neutron flux spectra (thermal, intermediate, and fast flux spectra). Data coming from many ICSBEP experiments are used (PU-SOL-THERM, PU-MET-FAST, PU-MET-INTER and PU-MET-MIXED) and French mock-up experiments are also investigated (EOLE for thermal neutron flux spectrum and MASURCA for fast neutron flux spectrum). This study shows that many experiments and neutron parameters are very sensitive to

  2. Neutron generators at Purnima Lab

    International Nuclear Information System (INIS)

    Patel, Tarun; Sinha, Amar

    2015-01-01

    Neutron sources are in a great demand in many area like research, nuclear waste management, industrial process control, medical and also security. Major sources of neutrons are nuclear reactors, radioisotopes and accelerator based neutron generators. For many field applications, reactors cannot be used due to its large size, complicated system, high cost and also safety issues. Radioisotopes like Pu-Be, Am-Be, Cf, are extensively used for many industrial applications. But they are limited in their use due to their low source strength and also handling difficulties due to radioactivity. They are also not suitable for pulsed neutron applications. In contrast, compact size, pulsed operation, on/off operation etc.of accelerator based neutron generators make them very popular for many applications. Particle accelerators based on different types of neutron generators have been developed around the world. Among these deuteron accelerator based D-D and D-T neutron generators are widely used as they produce mono-energetic fast neutrons and in particular high yield of D-T neutron can be obtained with less than 300 KV of accelerating voltage

  3. Laser neutron generator

    International Nuclear Information System (INIS)

    Anan'in, O.B.; Bespalov, D.F.; Bykovskii, Yu.A.; Kozyrev, Yu.P.; Mints, A.Z.; Riabov, E.V.; Tsybin, A.S.; Cherkasov, Yu.; Shikanov, A.E.

    1986-01-01

    Information is presented concerning devices for producing intense neutrons flows, and may be utilized in nuclear geophysics for carrying out pulsed neutron logging of wells, in studies of the critical characteristics of nuclear reactors, for activation analysis, radiation therapy, defectoscopy, and so on

  4. Determination of protein content in grains by radioactive thermal neutron capture prompt gamma rays analysis

    International Nuclear Information System (INIS)

    Carbonari, A.W.

    1983-01-01

    The radioactive thermal neutron capture prompt gamma rays technique can be used to determinate the nitrogen content in grains without chemical destruction, with good precision and relative rapidity. This determination is based on the detection of prompt gamma rays emitted by the 14 N(n,γ) 15 N reaction product. The samples has been irradiated the tanGencial tube of the IEA-R1 research reator and a pair spectrometer has been used for the detection of the prompt gamma rays. The nitrogen content is determinated in several samples of soybean, commonbean, peas and rice, and the results is compared with typical nitrogen content for each grain. (Autor) [pt

  5. An assessment of prompt neutron reproduction time in a reflector dominated fast critical system: ELECTRA

    International Nuclear Information System (INIS)

    Suvdantsetseg, E.; Wallenius, J.

    2014-01-01

    Highlights: • Prompt neutron reproduction time of ELECTRA is evaluated. • Static and dynamic reproduction times are distinguished for ELECTRA. • Avery-Cohn’s two-region prompt neutron theory is applied. - Abstract: In this paper, an accurate method to evaluate the prompt neutron reproduction time for a reflector dominated fast critical reactor, ELECTRA, is discussed. To adequately handle the problem, explicit time dependent Monte Carlo calculations with MCNP, applying repeated time cut-off technique, are used and compared against the σ∼1/v time dependent absorber method, applying artificial cross-section data in the Monte Carlo code SERPENT. The results show that when a reflector plays a major role in criticality for fast neutron reactor, the two methods predict different physical parameters (Λ=69±2 ns and Λ=83±1 ns for time cut-off and the 1/v method respectively). The reason is explained by applying Avery-Cohn’s two-region prompt neutron model

  6. Use of borated polyethylene to improve low energy response of a prompt gamma based neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Ashwini, U.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2016-05-21

    The feasibility of using a combined sample of borated polyethylene and normal polyethylene to estimate neutron ambient dose equivalent from measured prompt gamma emissions is investigated theoretically to demonstrate improvements in low energy neutron dose response compared to only polyethylene. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of boron, hydrogen and carbon prompt gamma emissions to mono energetic neutrons. The weighted least square method is employed to arrive at the best linear combination of these responses that approximates the ICRP fluence to dose conversion coefficients well in the energy range of 10{sup −8} MeV to 14 MeV. The configuration of the combined system is optimized through FLUKA simulations. The proposed method is validated theoretically with five different workplace neutron spectra with satisfactory outcome. - Highlights: • An improved method is proposed for estimating H⁎(10) using prompt gamma emissions. • A combination of BHDPE and HDPE cylinders is used as a sample. • Linear combination of prompt gamma intensities approximates ICRP-DCC closely. • Feasibility of the method was tested theoretically using workplace neutron spectra.

  7. The 235U Prompt Fission Neutron Spectrum in the BR1 Reactor at SCK•CEN

    Science.gov (United States)

    Wagemans, Jan; Malambu, Edouard; Borms, Luc; Fiorito, Luca

    2016-02-01

    The BR1 research reactor at SCK•CEN has a spherical cavity in the graphite above the reactor core. In this cavity an accurately characterised Maxwellian thermal neutron field is present. Different converters can be loaded in the cavity in order to obtain other types of neutron (and gamma) irradiation fields. Inside the so-called MARK III converter a fast 235U(n,f) prompt fission neutron field can be obtained. With the support of MCNP calculations, irradiations in MARK III can be directly related to the pure 235U(n,f) prompt fission neutron spectrum. For this purpose MARK III spectrum averaged cross sections for the most relevant fluence dosimetry reactions have been determined. A calibration factor for absolute measurements has been determined applying activation dosimetry following ISO/IEC 17025 standards.

  8. The 235U Prompt Fission Neutron Spectrum in the BR1 Reactor at SCK•CEN

    Directory of Open Access Journals (Sweden)

    Wagemans Jan

    2016-01-01

    Full Text Available The BR1 research reactor at SCK•CEN has a spherical cavity in the graphite above the reactor core. In this cavity an accurately characterised Maxwellian thermal neutron field is present. Different converters can be loaded in the cavity in order to obtain other types of neutron (and gamma irradiation fields. Inside the so-called MARK III converter a fast 235U(n,f prompt fission neutron field can be obtained. With the support of MCNP calculations, irradiations in MARK III can be directly related to the pure 235U(n,f prompt fission neutron spectrum. For this purpose MARK III spectrum averaged cross sections for the most relevant fluence dosimetry reactions have been determined. A calibration factor for absolute measurements has been determined applying activation dosimetry following ISO/IEC 17025 standards.

  9. An absolute measurement of 252Cf prompt fission neutron spectrum at low energy range

    International Nuclear Information System (INIS)

    Lajtai, A.; Dyachenko, P.P.; Kutzaeva, L.S.; Kononov, V.N.; Androsenko, P.A.; Androsenko, A.A.

    1983-01-01

    Prompt neutron energy spectrum at low energies (25 keV 252 Cf spontaneous fission has been measured with a time-of-flight technique on a 30 cm flight-path. Ionization chamber and lithium-glass were used as fission fragment and neutron detectors, respectively. Lithium glasses of NE-912 (containing 6 Li) and of NE-913 (containing 7 Li) 45 mm in diameter and 9.5 mm in thickness have been employed alternatively, for the registration of fission neutrons and gammas. For the correct determination of the multiscattering effects - the main difficulty of the low energy neutron spectrum measurements - a special geometry for the neutron detector was used. Special attention was paid also to the determination of the absolute efficiency of the neutron detector. The real response function of the spectrometer was determined by a Monte-Carlo calculation. The scattering material content of the ionization chamber containing a 252 Cf source was minimized. As a result of this measurement a prompt fission neutron spectrum of Maxwell type with a T=1.42 MeV parameter was obtained at this low energy range. We did not find any neutron excess or irregularities over the Maxwellian. (author)

  10. Measurements of prompt gamma-rays from fast-neutron induced fission with the LICORNE directional neutron source

    CERN Document Server

    Wilson, J N; Halipre, P; Oberstedt, S; Oberstedt, A

    2014-01-01

    At the IPN Orsay we have developed a unique, directional, fast neutron source called LICORNE, intended initially to facilitate prompt fission gamma measurements. The ability of the IPN Orsay tandem accelerator to produce intense beams of $^7$Li is exploited to produce quasi-monoenergetic neutrons between 0.5 - 4 MeV using the p($^7$Li,$^7$Be)n inverse reaction. The available fluxes of up to 7 × 10$^7$ neutrons/second/steradian for the thickest hydrogen-rich targets are comparable to similar installations, but with two added advantages: (i) The kinematic focusing produces a natural neutron beam collimation which allows placement of gamma detectors adjacent to the irradiated sample unimpeded by source neutrons. (ii) The background of scattered neutrons in the experimental hall is drastically reduced. The dedicated neutron converter was commissioned in June 2013. Some preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fas...

  11. The 3D tomographic image reconstruction software for prompt-gamma measurement of the boron neutron capture therapy

    International Nuclear Information System (INIS)

    Morozov, Boris; Auterinen, Iiro; Kotiluoto, Petri; Kortesniemi, Mika

    2006-01-01

    A tomographic imaging system based on the spatial distribution measurement of the neutron capture reaction during Boron Neutron Capture Therapy (BNCT) would be very useful for clinical purpose. Using gamma-detectors in a 2D-panel, boron neutron capture and hydrogen neutron capture gamma-rays emitted by the neutron irradiated region can be detected, and an image of the neutron capture events can be reconstructed. A 3D reconstruction software package has been written to support the development of a 3D prompt-gamma tomographic system. The package consists of three independent modules: phantom generation, reconstruction and evaluation modules. The reconstruction modules are based on algebraic approach of the iterative reconstruction algorithm (ART), and on the maximum likelihood estimation method (ML-EM). In addition to that, two subsets of the ART, the simultaneous iterative reconstruction technique (SIRT) and the component averaging algorithms (CAV) have been included to the package employing parallel codes for multiprocessor architecture. All implemented algorithms use two different field functions for the reconstruction of the region. One is traditional voxel function, another is, so called, blob function, smooth spherically symmetric generalized Kaiser-Bessel function. The generation module provides the phantom and projections with background by tracing the prompt gamma-rays for a given scanner geometry. The evaluation module makes statistical comparisons between the generated and reconstructed images, and provides figure-of-merit (FOM) values for the applied reconstruction algorithms. The package has been written in C language and tested under Linux and Windows platforms. The simple graphical user interface (GUI) is used for command execution and visualization purposed. (author)

  12. A novel method to assay special nuclear materials by measuring prompt neutrons from polarized photofission

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.M., E-mail: mueller@tunl.duke.edu [Triangle Universities Nuclear Laboratory, Durham, NC 27710 (United States); Department of Physics, Duke University, Durham, NC 27708 (United States); Ahmed, M.W. [Triangle Universities Nuclear Laboratory, Durham, NC 27710 (United States); Department of Physics, Duke University, Durham, NC 27708 (United States); Department of Mathematics and Physics, North Carolina Central University, Durham, NC 27707 (United States); Weller, H.R. [Triangle Universities Nuclear Laboratory, Durham, NC 27710 (United States); Department of Physics, Duke University, Durham, NC 27708 (United States)

    2014-08-01

    A novel method of measuring the enrichment of special nuclear material is presented. Recent photofission measurements using a linearly polarized γ-ray beam were performed on samples of {sup 232}Th, {sup 233,235,238}U, {sup 237}Np, and {sup 239,240}Pu. Prompt neutron polarization asymmetries, defined to be the difference in the prompt neutron yields parallel and perpendicular to the plane of beam polarization divided by their sum, were measured. It was discovered that the prompt neutron polarization asymmetries differed significantly depending on the sample. Prompt neutrons from photofission of even–even (non-fissile) targets had significant polarization asymmetries (∼0.2 to 0.5), while those from odd-A (generally fissile) targets had polarization asymmetries close to zero. This difference in the polarization asymmetries could be exploited to measure the fissile versus non-fissile content of special nuclear materials, and potentially to detect the presence of fissile material during active interrogation. The proposed technique, its expected performance, and its potential applicability are discussed.

  13. A novel method to assay special nuclear materials by measuring prompt neutrons from polarized photofission

    International Nuclear Information System (INIS)

    Mueller, J.M.; Ahmed, M.W.; Weller, H.R.

    2014-01-01

    A novel method of measuring the enrichment of special nuclear material is presented. Recent photofission measurements using a linearly polarized γ-ray beam were performed on samples of 232 Th, 233,235,238 U, 237 Np, and 239,240 Pu. Prompt neutron polarization asymmetries, defined to be the difference in the prompt neutron yields parallel and perpendicular to the plane of beam polarization divided by their sum, were measured. It was discovered that the prompt neutron polarization asymmetries differed significantly depending on the sample. Prompt neutrons from photofission of even–even (non-fissile) targets had significant polarization asymmetries (∼0.2 to 0.5), while those from odd-A (generally fissile) targets had polarization asymmetries close to zero. This difference in the polarization asymmetries could be exploited to measure the fissile versus non-fissile content of special nuclear materials, and potentially to detect the presence of fissile material during active interrogation. The proposed technique, its expected performance, and its potential applicability are discussed

  14. The measurement of prompt neutron spectrum in spontaneous fission of {sup 244}Cm

    Energy Technology Data Exchange (ETDEWEB)

    Batenkov, O.I.; Boykov, G.S.; Drapchinsky, L.V.; Majorov, M.Ju.; Trenkin, V.A. [V.G. Khlopin Radium Inst., Saint Petersburg (Russian Federation)

    1997-03-01

    Under the Program of Measurements of Prompt Fission Neutron Spectra of Minor Actinides for Transmutation Purposes the integral neutron spectrum in spontaneous fission of {sup 244}Cm has been measured by the time-of-flight method in the energy range of 0.1-15 MeV relative to the standard neutron spectrum in {sup 252}Cf spontaneous fission. Essential attention was paid to revealing of possible systematic errors. It is shown, that the {sup 244}Cm spectrum shape may be well described by using Mannhart evaluation with appropriate parameter of Maxwell temperature T{sub M} = 1.37 MeV. (author)

  15. Prompt gamma-ray analysis using JRR-3M cold and thermal neutron guide beams

    International Nuclear Information System (INIS)

    Yonezawa, C.; Haji Wood, A.K.; Magara, M.; Hoshi, M.; Tachikawa, E.; Sawahata, H.; Ito, Y.

    1993-01-01

    A permanent and stand-alone neutron-induced prompt gamma-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M has been constructed. Neutron flux at the sample positions were 1.4x10 8 and 2.4x10 7 n cm -2 s -1 for the cold and thermal neutrons, respectively. The γ-ray spectrometer is equipped to acquire three modes of spectra simultaneously: single mode, Compton suppression mode and pair mode, in an energy range up to 12 MeV. Owing to the cold neutron guide beam and the low γ-ray background system, analytical sensitivities and detection limits better than those in other PGA systems have been achieved. Analytical sensitivity and detection limit for 73 elements were measured. Boron, Gd, Sm and Cd are the most sensitive elements with detection limits down to 1 to 10 ng. For some elements such as F, Al, V, Eu and Hf, decay γ-rays are more sensitive compared to their respective prompt γ-ray. Analytical sensitivity of several heavy elements through detection of characteristic X-rays was higher than that through the prompt γ-ray detection. Analytical applicability of some sensitive elements such as B, H, Gd and Sm were examined. Isotopic analysis of Ni and Si were also examined. (author)

  16. Refinements in the Los Alamos model of the prompt fission neutron spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Madland, D.G., E-mail: dgm@lanl.gov; Kahler, A.C.

    2017-01-15

    This paper presents a number of refinements to the original Los Alamos model of the prompt fission neutron spectrum and average prompt neutron multiplicity as derived in 1982. The four refinements are due to new measurements of the spectrum and related fission observables many of which were not available in 1982. They are also due to a number of detailed studies and comparisons of the model with previous and present experimental results including not only the differential spectrum, but also integral cross sections measured in the field of the differential spectrum. The four refinements are (a) separate neutron contributions in binary fission, (b) departure from statistical equilibrium at scission, (c) fission-fragment nuclear level-density models, and (d) center-of-mass anisotropy. With these refinements, for the first time, good agreement has been obtained for both differential and integral measurements using the same Los Alamos model spectrum.

  17. Prompt neutron decay constant estimation of RSG-GAS at high power noise experiment

    International Nuclear Information System (INIS)

    Jujuratisbela, U.; Kristedjo; Tukiran; Pinem, S.; Iman, J.; Puryono; Sanjaya, A.; Suwarno

    1998-01-01

    The determination of prompt neutron decay constant (α) of RGS-GAS by using low power noise experiment method at the equilibrium core indicated that the result is not good. The bad result was due to the small ratio of the noise signal to background which was caused by low detector efficiency or contaminated core after long time operation. To solve the problem is tried by using noise experiment technique at high power. The voltage output of neutron detectors at power of 5, 12, and 23 MW were connected to preamplifier and filter then to the Dynamic Signal Analyzer Version-2 and then the power spectral density of each channel of JKT04 and JKT03, the cut off frequency of each channel can be determined by using linear regression technique such that the prompt neutron decay constant can be estimated

  18. Prompt neutron decay constants and subcritical measurements for material control and accountability in SHEBA

    International Nuclear Information System (INIS)

    Sanchez, R.; Jaegers, P.

    1998-01-01

    Rossi-Alpha measurements were performed on the SHEBA assembly to determine the prompt neutron decay constants. These prompt neutron decay constants represent an eigenvalue characteristic of this particular assembly, which can be used to infer the amount of fissile material in the assembly. In addition, subcritical measurements using Rossi-Alpha and the source-jerk techniques were also performed on the SHEBA assembly. These measurements were compared against TWODANT calculations and agreed quite well. The subcritical measurements were also used to obtain a unique signature that represented the amount of material associated with the degree of subcriticality of the SHEBA assembly. Finally, the Feynman variance-to-mean technique in conjunction with TWODANT, were used to determine the effective delayed neutron fraction for the SHEBA assembly

  19. Prompt fission neutron spectra of n + 235U above the (n, nf) fission threshold

    International Nuclear Information System (INIS)

    Shu Nengchuan; Chen Yongjing; Liu Tingjin; Jia Min

    2015-01-01

    Calculations of prompt fission neutron spectra (PFNS) from the 235 U(n, f) reaction were performed with a semi-empirical method for En = 7.0 and 14.7 MeV neutron energies. The total PFNS were obtained as a superposition of (n, xnf) pre-fission neutron spectra and post-fission spectra of neutrons which were evaporated from fission fragments, and these two kinds of spectra were taken as an expression of the evaporation spectrum. The contributions of (n, xnf) fission neutron spectra on the calculated PFNS were discussed. The results show that emission of one or two neutrons in the (n, nf) or (n, 2nf) reactions influences the PFNS shape, and the neutron spectra of the (n, xnf) fission-channel are soft compared with the neutron spectra of the (n, f) fission channel. In addition, analysis of the multiple-chance fission component showed that second-chance fission dominates the PFNS with an incident neutron energy of 14.7 MeV whereas first-chance fission dominates the 7 MeV case. (authors)

  20. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    Science.gov (United States)

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  1. Energy measurement of prompt fission neutrons in 239Pu(n,f) for incident neutron energies from 1 to 200 MeV

    CERN Document Server

    Chatillon, A; Granier, Th; Laurent, B; Taïeb, J; Noda, S; Haight, R C; Devlin, M; Nelson, R O; O’Donnell, J M

    2010-01-01

    Prompt fission neutron spectra in the neutron-induced fission of 239Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Preliminary results are discussed and compared to theoretical model calculation.

  2. Development of neutron induced prompt γ-ray spectroscopy system using 252Cf

    International Nuclear Information System (INIS)

    Park, Yong-Joon; Song, Byung-Chul; Jee, Kwang-Yong

    2003-01-01

    For the design and set-up of neutron induced prompt γ-ray spectroscopy system using 252 Cf neutron source, the effects of shielding and moderator materials have been examined. The 252 Cf source being used for TLD badge calibration in Korea Atomic Energy Research Institute was utilized for this preliminary experiment. The γ-ray background and prompt γ-ray spectrum of the sample containing Cl were measured using HPGe (GMX 69% relative efficiency) located at the inside of the system connected to notebook PC at the outside of the system (about 20 meter distance). The background activities of neutron and γ-rays were measured with neutron survey meter as well as γ-ray survey meters, respectively and the system was designed to minimize the activities. Prompt γ-ray spectrum was measured using γ-γ coincident system for reduce the background and the continuum spectrum. The optimum system was designed and set up using the experimental data obtained

  3. Prompt-gamma spectrometry for the optimization of reactor neutron beams in biomedical research

    International Nuclear Information System (INIS)

    Borisov, G.I.; Komkov, M.M.; Leonov, V.F.

    1988-01-01

    In order to select the optimal spectral composition and size for the reactor neutron beams applied to in vivo analysis and therapy in biomedical research it is necessary to determine the spatial slow-neutron flux distributions produced by the beam in the irradiated object and to calculate or measure the neutron dose equivalents of both the original spectrum and the moderated neutrons. In this study the maximum neutron dose equivalents are found by spectrometry of the prompt-γ emission from the interaction of neutrons with atomic nuclei in the irradiated object. Different spectral distributions were produced by using an unfiltered beam together with filters of quartz, cadmium, 10 B, iron, aluminum, and sulfur. The phantom used was a tank filled with an aqueous solution of urea. Cadmium-containing organs were simulated. For in vivo neutron-activation analysis of human tissues at a depth of 2-5 cm it was found advisable to use neutrons of 20-40 keV mean energy with a beam area of at least 45 cm 2

  4. Cold neutron prompt gamma activation analysis at NIST; A progress report

    Energy Technology Data Exchange (ETDEWEB)

    Paul, R L; Lindstrom, R M [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Div. of Inorganic Analytical Research; Vincent, D H [Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering

    1994-05-01

    An instrument for prompt gamma-ray activation analysis is now in operation at the NIST Cold Neutron Research Facility (CNRF). The cold neutron beam is relatively free of contamination by fast neutrons and reactor gamma rays, and the neutron fluence rate is 1.5 x 10 [sup 8] cm [sup -2] x s [sup -1] (thermal equivalent). As a result of a compact target-detector geometry the sensitivity is better by a factor of as much as seven than that obtained with an existing thermal instrument, and hydrogen background is a factor of 50 lower. This instrument was applied to multielement analysis of the Allende meteorite and other materials. (author) 14 refs.; 2 figs.; 1 tab.

  5. Simultaneous measurement of fission fragments and prompt neutrons for thermal neutron-induced fission of U-235

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Katsuhisa; Yamamoto, Hideki; Kimura, Itsuro; Nakagome, Yoshihiro [Kyoto Univ. (Japan)

    1997-03-01

    Simultaneous measurement of fission fragments and prompt neutrons following the thermal neutron induced fission of U-235 has been performed in order to obtain the neutron multiplicity (v) and its emission energy ({eta}) against the specified mass (m{sup *}) and the total kinetic energy (TKE). The obtained value of -dv/dTKE(m{sup *}) showed a saw-tooth distribution. The average neutron energy <{eta}>(m{sup *}) had a distribution with a reflection symmetry around the half mass division. The measurement also gave the level density parameters of the specified fragment, a(m{sup *}), and this parameters showed a saw-tooth trend too. The analysis by a phenomenological description of this parameters including the shell and collective effects suggested the existence of a collective motion of the fission fragments. (author)

  6. Evaluating the 239Pu Prompt Fission Neutron Spectrum Induced by Thermal to 30 MeV Neutrons

    Directory of Open Access Journals (Sweden)

    Neudecker D.

    2016-01-01

    Full Text Available We present a new evaluation of the 239Pu prompt fission neutron spectrum (PFNS induced by thermal to 30 MeV neutrons. Compared to the ENDF/B-VII.1 evaluation, this one includes recently published experimental data as well as an improved and extended model description to predict PFNS. For instance, the pre-equilibrium neutron emission component to the PFNS is considered and the incident energy dependence of model parameters is parametrized more realistically. Experimental and model parameter uncertainties and covariances are estimated in detail. Also, evaluated covariances are provided between all PFNS at different incident neutron energies. Selected evaluation results and first benchmark calculations using this evaluation are briefly discussed.

  7. Compact Neutron Generators for Medical, Home Land Security, and Planetary Exploration

    CERN Document Server

    Reijonen, Jani

    2005-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0 - 9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration in form of neutron based, sub-surface hydrogen detection systems. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Three main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-c...

  8. Thermoelastic expansion in prompt-critical neutron pulse idealized in a fissile metallic sphere

    International Nuclear Information System (INIS)

    Barroso, D.E.G.; Ribeiro, S.G.

    1985-01-01

    Prompt critical pulses in solid and homogeneous spheres of enriched uranium (93%) and metallic plutonium are studied. The feedback mechanism of the negative inserted reactivity is given by the elastic expansion due to the increase of the temperature in the sphere. Thermomechanical behavior and the capability of the system to become subcritical without a very large increase of energy released in the pulse are analysed. The neutronic and thermoelasticity equations are solved in the time. (M.C.K.) [pt

  9. Measurement of prompt fission gamma-ray spectra in fast neutron-induced fission

    International Nuclear Information System (INIS)

    Laborie, J.M.; Belier, G.; Taieb, J.

    2012-01-01

    Knowledge of prompt fission gamma-ray emission has been of major interest in reactor physics for a few years. Since very few experimental spectra were ever published until now, new measurements would be also valuable to improve our understanding of the fission process. An experimental method is currently being developed to measure the prompt fission gamma-ray spectrum from some tens keV up to 10 MeV at least. The mean multiplicity and total energy could be deduced. In this method, the gamma-rays are measured with a bismuth germanate (BGO) detector which has the advantage to present a high P/T ratio and a high efficiency compared to other gamma-ray detectors. The prompt fission neutrons are rejected by the time of flight technique between the BGO detector and a fission trigger given by a fission chamber or a scintillating active target. Energy and efficiency calibration of the BGO detector were carried out up to 10.76 MeV by means of the Al-27(p, gamma) reaction. First prompt fission gamma-ray spectrum measurements performed for the spontaneous fission of Cf-252 and for 1.7 and 15.6 MeV neutron-induced fission of U-238 at the CEA, DAM, DIF Van de Graaff accelerator, will be presented. (authors)

  10. Pulsed neutron generator for use with pulsed neutron activation techniques

    International Nuclear Information System (INIS)

    Rochau, G.E.

    1980-01-01

    A high-output, transportable, pulsed neutron generator has been developed by Sandia National Laboratories for use with Pulsed Neutron Activation (PNA) techniques. The PNA neutron generator generates > 10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. Each operation of the unit will produce a nominal total neutron output of 1.2 x 10 10 neutrons. The generator has been designed to be easily repaired and modified. The unit requires no additional equipment for operation or measurement of output

  11. The LANL/LLNL Program to Measure Prompt Fission Neutron Spectra at LANSCE

    Science.gov (United States)

    Haight, Robert; Wu, Ching Yen; Lee, Hye Young; Taddeucci, Terry; Mosby, Shea; O'Donnell, John; Fotiades, Nikolaos; Devlin, Mattew; Ullmann, John; Nelson, Ronald; Wender, Stephen; White, Morgan; Solomon, Clell; Neudecker, Denise; Talou, Patrick; Rising, Michael; Bucher, Brian; Buckner, Matthew; Henderson, Roger

    2015-10-01

    Accurate data on the spectrum of neutrons emitted in neutron-induced fission are needed for applications and for a better understanding of the fission process. At LANSCE we have made important progress in understanding systematic uncertainties and in obtaining data for 235U on the low-energy part of the prompt fission neutron spectra (PFNS), a particularly difficult region because down-scattered neutrons go in this direction. We use a double time-of-flight technique to determine energies of incoming and outgoing neutrons. With data acquisition via waveform digitizers, accidental coincidences between fission chamber and neutron detector are measured to high statistical accuracy and then subtracted from measured events. Monte Carlo simulations with high performance computers have proven to be essential in the design to minimize neutron scattering and in calculating detector response. Results from one of three approaches to analyzing the data will be presented. This work is funded by the US Department of Energy, National Nuclear Security Administration and Office of Nuclear Physics.

  12. High efficiency focus neutron generator

    Science.gov (United States)

    Sadeghi, H.; Amrollahi, R.; Zare, M.; Fazelpour, S.

    2017-12-01

    In the present paper, the new idea to increase the neutron yield of plasma focus devices is investigated and the results are presented. Based on many studies, more than 90% of neutrons in plasma focus devices were produced by beam target interactions and only 10% of them were due to thermonuclear reactions. While propounding the new idea, the number of collisions between deuteron ions and deuterium gas atoms were increased remarkably well. The COMSOL Multiphysics 5.2 was used to study the given idea in the known 28 plasma focus devices. In this circumstance, the neutron yield of this system was also obtained and reported. Finally, it was found that in the ENEA device with 1 Hz working frequency, 1.1 × 109 and 1.1 × 1011 neutrons per second were produced by D-D and D-T reactions, respectively. In addition, in the NX2 device with 16 Hz working frequency, 1.34 × 1010 and 1.34 × 1012 neutrons per second were produced by D-D and D-T reactions, respectively. The results show that with regards to the sizes and energy of these devices, they can be used as the efficient neutron generators.

  13. Prompt and delay gamma ray measurements for 'in vivo' neutron activation analysis using a cyclic system

    International Nuclear Information System (INIS)

    Matthews, I.P.

    1979-09-01

    Early attempts at determining the elemental composition of the body by radioactive isotope dilution techniques are reviewed. The development and current status of in-vivo neutron activation analysis and the ways in which it supersedes or supplements certain of the former techniques are outlined. An irradiation facility is described which employs a 5 Ci neutron source and is capable of performing prompt and delay γ-ray measurements as well as cyclic activation. The uniformity of thermal neutron flux in a phantom is demonstrated and the neutron spectrum at a depth in the phantom has been obtained by means of threshold detectors. An examination is made of the possible applications of the Monte Carlo method to the design of irradiation and detection facilities and in yielding information about inaccessible areas. Detection limits for the bulk body elements and trace elements are presented. It is shown that the depth of a region of the body can be determined from a prompt gamma ray spectrum. This technique can be used to correct measurements when it is known that activation and detection is non-uniform. The feasibility of using a C.T. whole body scanner to measure bone demineralisation is explored. (author)

  14. Measurement of prompt neutron spectra from the "2"3"9Pu(n, f ) fission reaction for incident neutron energies from 1 to 200 MeV

    International Nuclear Information System (INIS)

    Chatillon, A.; Belier, G.; Granier, T.; Laurent, B.; Morillon, B.; Taieb, J.; Haight, R.C.; Devlin, M.; Nelson, R.O.; Noda, R.S.; O'Donnell, J.M.

    2014-01-01

    Prompt fission neutron spectra in the neutron-induced fission of "2"3"9Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Mean energies deduced from the prompt fission neutron spectra (PFNS) lead to the observation of the opening of the second chance fission at 7 MeV and to indications for the openings of fission channels of third and fourth chances. Moreover, the general trend of the measured PFNS is well reproduced by the different models. The comparison between data and models presents, however, two discrepancies. First, the prompt neutron mean energy seems constant for neutron energy, at least up to 7 MeV, whereas in the theoretical calculations it is continuously increasing. Second, data disagree with models on the shape of the high energy part of the PFNS, where our data suggest a softer spectrum than the predictions. (authors)

  15. The Sealed Tube Neutron Generator

    International Nuclear Information System (INIS)

    Tunnell, L.N.; Beyerle, A.; Durkee, R.; Headley, G.; Hurley, P.

    1992-01-01

    A Sealed Tube Neutron Generator (STNG) has been designed and tested at Special Technologies Laboratories (STL) in Santa Barbara, California. Unlike similar tubes that have been used for years in other applications, e.g., by the oil well logging industry, the present device was designed primarily to be part of the Associated Particle Imaging (API) system. Consequently, the size and quality of the neutron spot produced by the STNG is of primary importance. Results from initial measurements indicate that performance goals are satisfied

  16. Compact ion source neutron generator

    Science.gov (United States)

    Schenkel, Thomas; Persaud, Arun; Kapadia, Rehan; Javey, Ali; Chang-Hasnain, Constance; Rangelow, Ivo; Kwan, Joe

    2015-10-13

    A neutron generator includes a conductive substrate comprising a plurality of conductive nanostructures with free-standing tips and a source of an atomic species to introduce the atomic species in proximity to the free-standing tips. A target placed apart from the substrate is voltage biased relative to the substrate to ionize and accelerate the ionized atomic species toward the target. The target includes an element capable of a nuclear fusion reaction with the ionized atomic species to produce a one or more neutrons as a reaction by-product.

  17. {sup 252}Cf spontaneous prompt fission neutron spectrum measured at 0 degree and 180 degree relative to the fragment motion

    Energy Technology Data Exchange (ETDEWEB)

    Shanglian, Bao; Jinquan, Liu [Beijing Univ., BJ (China); Batenkov, O I; Blinov, M V; Smirnov, S N [V.G. Khlopin Radium Institute, ST. Petersburg (Russian Federation)

    1994-09-01

    The {sup 252}Cf spontaneous prompt fission neutron spectrum at 0 degree and 180 degree relative to the motion direction of corresponding fission fragments was measured. High angular resolution for fragment measurements and high energy resolution for neutron measurements were obtained using multi-parameter TOF spectrometer. The results showed that there is a symmetric distribution of `forward` and `backward` for low energy in C.M.S. neutrons, which was an evidence of nonequilibrium neutrons existed in fission process.

  18. Source characterization of Purnima Neutron Generator (PNG)

    International Nuclear Information System (INIS)

    Bishnoi, Saroj; Patel, T.; Paul, Ram K.; Sarkar, P.S.; Adhikari, P.S.; Sinha, Amar

    2011-01-01

    The use of 14.1 MeV neutron generators for the applications such as elemental analysis, Accelerated Driven System (ADS) study, fast neutron radiography requires the characterization of neutron source i.e neutron yield (emission rate in n/sec), neutron dose, beam spot size and energy spectrum. In this paper, a series of experiments carried out to characterize this neutron source. The neutron source has been quantified with neutron emission rate, neutron dose at various source strength and beam spot size at target position

  19. Search for sp-interference effect in emission of prompt neutrons of sup 2 sup 3 sup 5 U fission by thermal polarized neutrons

    CERN Document Server

    Danilyan, G V; Pavlov, V S; Fedorov, A V

    2001-01-01

    The results of the experiment for the search of the sp-interference effect in the distribution of the prompt neutrons of the sup 2 sup 3 sup 5 U fission by thermal polarized neutrons are presented. The experiment is carried out on the polarized neutrons beam of the MIFI reactor. The scheme of the installation and the flight time spectrum are presented

  20. Method of assaying uranium with prompt fission and thermal neutron borehole logging adjusted by borehole physical characteristics

    International Nuclear Information System (INIS)

    Barnard, R.W.; Jensen, D.H.

    1982-01-01

    Uranium formations are assayed by prompt fission neutron logging techniques. The uranium in the formation is proportional to the ratio of epithermal counts to thermal or eqithermal dieaway. Various calibration factors enhance the accuracy of the measurement

  1. Prompt-gamma neutron activation analysis for the non-destructive characterization of radioactive wastes; Prompt-Gamma-Neutronen-Aktivierungs-Analyse zur zerstoerungsfreien Charakterisierung radioaktiver Abfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Kettler, John Paul Hermann

    2010-07-01

    In Germany, stringent official regulations govern the handling and final storage of radioactive waste. For this reason, the Federal Government has opted for final storage of radioactive waste with negligible heat generation in deep geological formations. At present the Konrad mine in Salzgitter will be rebuilt as a final disposal, the start of operation is scheduled for 2014. Radioactive waste with negligible heat generation originates from the operation and decommissioning of nuclear power plants, the medical sector or from research establishments. The requirements of the planning approval decision to build up the disposal Konrad, published on the 22{sup nd} of May 2002, obligate the waste producer to consider the limits for chemotoxic substances and to document the waste content. Before the radioactive waste can be stored in the final disposal, it is necessary to characterize the waste composition, relating to the concentration of water polluting substances. In particular for the wastes produced in the year before 1990, the so-called old wastes, there is a lack of documentation. The chemotoxicity of old wastes can mostly only characterized by time consuming and destructive methods. Furthermore these methods produce high costs, which depend on the arrangements to avoid contamination, to comply with the radiation protection and for the conditioning of the wastes. A prototype system, based on the Prompt-Gamma-Neutron-Activation-Analysis (PGNAA) with 14 MeV neutrons, has been developed in this work. This system allows the characterization of large samples, like 25 and 50 l drums. The signature of the element composition is in this processed by gamma-ray spectroscopy. This work was focused, in addition to the feasibility of the system, to the neutron and photon transport in large samples. Therefore the neutron and photon self-absorption in dependence of the sample composition were the main part of interest. Computer simulations (MCNP) and experiments were performed to

  2. Monte Carlo simulation of the neutron-induced prompt γ ray spectroscopy of the CW abandoned by Japan

    International Nuclear Information System (INIS)

    Wang Bairong; Yang Zhongping; Zhang Wenzhong

    2005-01-01

    This paper introduced the principle of identifying the chemical weapon by neutron-induced prompt γ ray, simulated and analyzed the neutron-induced prompt γ ray spectroscopy of chemical weapon abandoned by Japan in the different condition, using the MCNP-4C Monte Carlo program, whereby supply important datum and reference for the aftertime deeper research and disposal of Japan-abandoned chemical weapon. (authors)

  3. The Monte Carlo simulation of the neutron-induced prompt gamma ray spectroscopy of the CW abandoned by Japan

    International Nuclear Information System (INIS)

    Wang Bairong; Yang Zhongping; Zhan Wenzhong

    2003-01-01

    This paper introduced the principle of identifying the chemical weapon abandoned by Japan by neutron-induced prompt gamma ray. Using the MCNP-4C Monte Carlo program, this paper simulated and analyzed the neutron-induced prompt gamma ray spectroscopy of chemical weapon abandoned by Japan, whereby supply important datum and reference for the aftertime deeper research and disposal of Japan-abandoned chemical weapon. (authors)

  4. Prompt Neutron Decay Constant Determination Of Silicide Transition Core Using Noise Method

    International Nuclear Information System (INIS)

    Jujuratisbela, Uju; Yulianto, Yusi Eko; Cahyana

    2001-01-01

    Chairman of BATAN had decided to replace the Oxide fuel element type of RSG-GAS into silicide element type step by step. The replacement will create core transitions. Kinetic characteristic of the transition cores have to be monitored in order to know the deviation of core behavior. For that reason, the kinetic parameters have to be measured. Prompt neutron decay constant (alpha) is one of the kinetic parameters that has to be monitored continuously in the transition cores. In order not to disturb the normal operation of reactor, alpha parameter should be measured by using noise analysis method. The voltage of neutron flux at power of 15 MW is connected to preamplifier and filter then to the Dynamic Signal Analyzer Version-2 and then the auto power spectral density (APSD) was determined by using Fast Fourier transform. From the APSD curve of each channel of JKT03, the cut off frequency of each channel can be determined by using linear regression technique such that the prompt neutron decay constant can be estimated

  5. Fast digitization and discrimination of prompt neutron and photon signals using a novel silicon carbide detector

    International Nuclear Information System (INIS)

    Brandon W. Blackburn; James T. Johnson; Scott M. Watson; David L. Chichester; James L. Jones; Frank H. Ruddy; John G. Seidel; Robert W. Flammang

    2007-01-01

    Current requirements of some Homeland Security active interrogation projects for the detection of Special Nuclear Material (SNM) necessitate the development of faster inspection and acquisition capabilities. In order to do so, fast detectors which can operate during and shortly after intense interrogation radiation flashes are being developed. Novel silicon carbide (SiC) semiconductor Schottky diodes have been utilized as robust neutron and photon detectors in both pulsed photon and pulsed neutron fields and are being integrated into active inspection environments to allow exploitation of both prompt and delayed emissions. These detectors have demonstrated the capability of detecting both photon and neutron events during intense photon flashes typical of an active inspection environment. Beyond the inherent insensitivity of SiC to gamma radiation, fast digitization and processing has demonstrated that pulse shape discrimination (PSD) in combination with amplitude discrimination can further suppress unwanted gamma signals and extract fast neutron signatures. Usable neutron signals have been extracted from mixed radiation fields where the background has exceeded the signals of interest by >1000:1

  6. Monte Carlo calculations and neutron spectrometry in quantitative prompt gamma neutron activation analysis (PGNAA) of bulk samples using an isotopic neutron source

    International Nuclear Information System (INIS)

    Spyrou, N.M.; Awotwi-Pratt, J.B.; Williams, A.M.

    2004-01-01

    An activation analysis facility based on an isotopic neutron source (185 GBq 241 Am/Be) which can perform both prompt and cyclic activation analysis on bulk samples, has been used for more than 20 years in many applications including 'in vivo' activation analysis and the determination of the composition of bio-environmental samples, such as, landfill waste and coal. Although the comparator method is often employed, because of the variety in shape, size and elemental composition of these bulk samples, it is often difficult and time consuming to construct appropriate comparator samples for reference. One of the obvious problems is the distribution and energy of the neutron flux in these bulk and comparator samples. In recent years, it was attempted to adopt the absolute method based on a monostandard and to make calculations using a Monte Carlo code (MCNP4C2) to explore this further. In particular, a model of the irradiation facility has been made using the MCNP4C2 code in order to investigate the factors contributing to the quantitative determination of the elemental concentrations through prompt gamma neutron activation analysis (PGNAA) and most importantly, to estimate how the neutron energy spectrum and neutron dose vary with penetration depth into the sample. This simulation is compared against the scattered and transmitted neutron energy spectra that are experimentally and empirically determined using a portable neutron spectrometry system. (author)

  7. Calculation of thermal neutron self-shielding correction factors for aqueous bulk sample prompt gamma neutron activation analysis using the MCNP code

    International Nuclear Information System (INIS)

    Nasrabadi, M.N.; Jalali, M.; Mohammadi, A.

    2007-01-01

    In this work thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing materials is studied using bulk sample prompt gamma neutron activation analysis (BSPGNAA) with the MCNP code. The code was used to perform three dimensional simulations of a neutron source, neutron detector and sample of various material compositions. The MCNP model was validated against experimental measurements of the neutron flux performed using a BF 3 detector. Simulations were performed to predict thermal neutron self-shielding in aqueous bulk samples containing neutron absorbing solutes. In practice, the MCNP calculations are combined with experimental measurements of the relative thermal neutron flux over the sample's surface, with respect to a reference water sample, to derive the thermal neutron self-shielding within the sample. The proposed methodology can be used for the determination of the elemental concentration of unknown aqueous samples by BSPGNAA where knowledge of the average thermal neutron flux within the sample volume is required

  8. Neutron generator ion source pulser

    International Nuclear Information System (INIS)

    Peelman, H.E.

    1987-01-01

    This patent describes, for use with a pulsed neutron generator in a logging tool lowered in a borehole, a pulsed high voltage source having an output terminal adapted to be connected to pulse neutron generator. The power supply comprises: (a) high voltage supply means; (b) field effect transistor means comprising at least a pair of field effect transistors serially connected between the high voltage supply means and ground; (c) an output terminal between the two transistors of the field effect transistor means, the output terminal adapted to be connected by a conductor to provide pulsed high voltage to a neutron generator; (d) control pulse forming means connected to the gates of the respective two transistors, the pulse forming means forming control pulses selectively switching the transistors off and on in timed sequence to thereby connect the output terminal to the high voltage supply means, and (e) diode means connected to the gates of the transistors to limit gate voltage for operation of the transistors

  9. Study of neutron fields around an intense neutron generator.

    Science.gov (United States)

    Kicka, L; Machrafi, R; Miller, A

    2017-12-01

    Neutron fields in the vicinity of the newly built neutron facility, at the University of Ontario Institute of Technology (UOIT), have been investigated in a series of Monte Carlo simulations and measurements. The facility hosts a P-385 neutron generator based on a deuterium-deuterium fusion reaction. The neutron fluence at different locations around the neutron generator facility has been simulated using MCNPX 2.7E Monte Carlo particle transport program. To characterize neutron fields, three neutron sources were modeled with distributions corresponding to different incident deuteron energies of 90kV, 110kV, and 130kV. Measurements have been carried out to determine the dose rate at locations adjacent to the generator using bubble detectors (BDs). The neutron intensity was evaluated and the total dose rates corresponding to different applied acceleration potentials were estimated at various locations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Performance test results of noninvasive characterization of RCRA surrogate waste by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Propp, W.A.

    1997-11-01

    A performance evaluation to determine the feasibility of using prompt gamma neutron activation analysis (PGNAA) for noninvasive, quantitative assay of mixed waste containers was sponsored by DOE's Office of Technology Development (OTD), the Mixed Waste Focus Area (MWFA), and the Idaho National Engineering and Environmental Laboratory (INEEL). The evaluation was conducted using a surrogate waste, based on Portland cement, that was spiked with three RCRA metals, mercury, cadmium, and lead. The results indicate that PGNAA has potential as a process monitor. However, further development is required to improve its sensitivity to meet regulatory requirements for determination of these RCRA metals

  11. In vivo Prompt Gamma Neutron Activation Analysis Facility for Total Body Nitrogen and Cd

    International Nuclear Information System (INIS)

    Munive, Marco; Revilla, Angel; Solis, Jose L.

    2007-01-01

    A Prompt Gamma Neutron Activation Analysis (PGNAA) system has been designed and constructed to measure the total body nitrogen and Cd for in vivo studies. An aqueous solution of KNO 3 was used as phantom for system calibration. The facility has been used to monitor total body nitrogen (TBN) of mice and found that is related to their diet. Some mice swallowed diluted water with Cl 2 Cd, and the presence of Cd was detected in the animals. The minimum Cd concentration that the system can detect was 20 ppm

  12. Statistical analysis for discrimination of prompt gamma ray peak induced by high energy neutron: Monte Carlo simulation study

    International Nuclear Information System (INIS)

    Do-Kun Yoon; Joo-Young Jung; Tae Suk Suh; Seong-Min Han

    2015-01-01

    The purpose of this research is a statistical analysis for discrimination of prompt gamma ray peak induced by the 14.1 MeV neutron particles from spectra using Monte Carlo simulation. For the simulation, the information of 18 detector materials was used to simulate spectra by the neutron capture reaction. The discrimination of nine prompt gamma ray peaks from the simulation of each detector material was performed. We presented the several comparison indexes of energy resolution performance depending on the detector material using the simulation and statistics for the prompt gamma activation analysis. (author)

  13. Prompt neutron decay constant for the Oak Ridge Research Reactor with 20 wt % 235U enriched fuel

    International Nuclear Information System (INIS)

    Ragan, G.E.; Mihalczo, J.T.

    1986-01-01

    This paper describes measurements of the prompt neutron decay constant at delayed criticality for the Oak Ridge Research Reactor (ORR) using 20 wt % 235 U enriched fuel and compares these measurements with similar measurements using 93.2 wt % 235 U enriched fuel. This reactor parameter is of interest because it affects the transient behavior of the reactor in prompt criticality accident situations. This experiment is part of a program to investigate the differences in the performance of research reactors fueled with highly enriched and low enriched uranium. The prompt neutron decay constants were obtained using noise analysis measurement techniques for a core with newly fabricated, unirradiated fuel elements

  14. Contributions to the prompt neutron activation analysis of industrially used coals and zinc roasting products

    International Nuclear Information System (INIS)

    Dammermann, H.

    1982-01-01

    The construction of an irradiation plant for calibration measurement by means of prompt neutron activation analysis is described. A 5.84 μg and 16.3 μg Cf-252 source serve as neutron sources. Tests have shown an inner centred arrangement to offer the best solution for sources of this strength. The use of the PNAA method for determining sulphur, iron and chloride content in brown coal was tested and calibration curves drawn. The sulphur content of the coal briquettes tested was found to be 0.27% S, the iron content amounting to 0.21% Fe and chloride to 0.06%. These values correlate closely with values obtained from wet chemical industrial analysis. (WI)

  15. The Canadian intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Tunnicliffe, P R

    1967-07-01

    Atomic Energy of Canada Ltd. has proposed construction of an Intense Neutron-Generator. The generator would produce uniquely-intense beams of thermal neutrons for solid-state and low-energy nuclear studies and would yield significant quantities of radioisotopes of both research and commercial value; it would also produce copious sources of mesons and energetic nucleons for use in intermediate-energy nuclear physics and in nuclear-structure studies. The primary neutron source of 10{sup 19}/sec would be generated by bombarding a heavy-element target with a continuous beam of 65 mA of 1 GeV protons. The target of circulating and cooled Pb-Bi eutectic would be surrounded by a tank of heavy water moderator yielding a maximum useful flux of 10{sup 16} thermal neutrons/cm{sup 2}/sec in the region where neutron beams can be extracted. This high-energy spallation process for producing neutrons is nearly four times more efficient in producing neutrons per unit of thermal energy released in the neutron source compared with a fission reactor. Nevertheless, if energy costs for producing the 65 MW proton beam are to be within reason, the machine producing the beam must be efficient. A D.C. machine is in principle ideal but practical achievement of 1 GV is not likely within the time desired. An accelerator where the protons gain energy from radio-frequency fields is the most likely prospect. We have selected a linear accelerator as our reference design and detailed theoretical and experimental studies are in progress. The machine is based on the Los Alamos Meson Physics Facility design reoptimized for continuous rather than pulsed operation. It is approximately one mile long and is expected to achieve nearly 50 percent overall efficiency. There are two major portions, an 'Alvarez' Section operating at 200 MHz accelerating the beam to about 150 MeV, followed by a 'Waveguide' section operating at 800 MHz. Protons are initially injected by an 0.75 MV D.C. accelerator. The Alvarez

  16. Development of high flux thermal neutron generator for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko H., E-mail: hannes@adelphitech.com [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Chen, Allan X.; Piestrup, Melvin A.; Gary, Charles K. [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Jones, Glenn [G& J Jones Enterprice, 7486 Brighton Ct, Dublin, CA 94568 (United States); Pantell, Richard H. [Department of Electrical Engineering, Stanford University, Stanford, CA (United States)

    2015-05-01

    The new model DD110MB neutron generator from Adelphi Technology produces thermal (<0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 10{sup 7} n/cm{sup 2}/s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 10{sup 10} n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques.

  17. The Prompt Gamma Neutron Activation Analysis Facility at ICN-Pitesti

    International Nuclear Information System (INIS)

    Barbos, D.; Paunoiu, C.; Mladin, M.; Cosma, C.

    2008-01-01

    PGNAA is a very widely applicable technique for determining the presence and amount of many elements simultaneously in samples ranging in size from micrograms to many grams. PGNAA is characterized by its capability for nondestructive multi-elemental analysis and its ability to analyse elements that cannot be determined by INAA. By means of this PGNAA method we are able to increase the performance of INAA method. A facility has been developed at Institute for Nuclear Research-Pitesti so that the unique features of prompt gamma-ray neutron activation analysis can be used to measure trace and major elements in samples. The facility is linked at the radial neutron beam tube at ACPR-TRIGA reactor. During the PGNAA-facility is in use the ACPR reactor will be operated in steady-state mode at 250 KW maximum power. The facility consists of a radial beam-port, external sample position with shielding, and induced prompt gamma-ray counting system.Thermal neutron flux with energy lower than cadmium cut-off at the sample position was measured using thin gold foil is: φ scd = 1.10 6 n/cm 2 /s with a cadmium ratio of:80.The gamma-ray detection system consist of an HpGe detector of 16% efficiency (detector model GC1518) with 1.85 keV resolution capability. The HpGe is mounted with its axis at 90 deg. with respect to the incident neutron beam at distance about 200mm from the sample position. To establish the performance capabilities of the facility, irradiation of pure element or sample compound standards were performed to identify the gama-ray energies from each element and their count rates

  18. The Prompt Fission Neutron Spectrum of 235U for Einc 0.7-5.0 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Jaime A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haight, Robert Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Donnell, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lee, Hye Young [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taddeucci, Terry Nicholas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kelly, Keegan John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fotiadis, Nikolaos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Neudecker, Denise [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); White, Morgan Curtis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Talou, Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rising, Michael Evan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solomon, Clell Jeffrey Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wu, Ching-Yen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bucher, Brian Michael [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buckner, Matthew Quinn [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henderson, Roger Alan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-03-23

    The Chi-Nu experiment aims to accurately measure the prompt fission neutron spectrum (PFNS) for the major actinides. At the Los Alamos Neutron Science Center (LANSCE), fission can be induced using the white neutron source. Using a two arm time of flight (T.O.F) technique; Chi-Nu presents a preliminary result of the low energy component of the 235U PFNS measured using an array of 22-Lithium glass scintillators.

  19. Experiment of Neutron Generation by Using Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Kim, Suk Kwon; Park, Chang Su; Jung, Nam Suk; Jung, Hwa Dong; Park, Ji Young; Hwang, Yong Seok; Choi, H.D.

    2005-01-01

    Experiment of neutron generation was performed by using a prototype D-D neutron generator. The characteristics of D-D neutron generation in drive-in target was studied. The increment of neutron yield by increasing ion beam energy was investigated, too

  20. GPU-based prompt gamma ray imaging from boron neutron capture therapy

    International Nuclear Information System (INIS)

    Yoon, Do-Kun; Jung, Joo-Young; Suk Suh, Tae; Jo Hong, Key; Sil Lee, Keum

    2015-01-01

    Purpose: The purpose of this research is to perform the fast reconstruction of a prompt gamma ray image using a graphics processing unit (GPU) computation from boron neutron capture therapy (BNCT) simulations. Methods: To evaluate the accuracy of the reconstructed image, a phantom including four boron uptake regions (BURs) was used in the simulation. After the Monte Carlo simulation of the BNCT, the modified ordered subset expectation maximization reconstruction algorithm using the GPU computation was used to reconstruct the images with fewer projections. The computation times for image reconstruction were compared between the GPU and the central processing unit (CPU). Also, the accuracy of the reconstructed image was evaluated by a receiver operating characteristic (ROC) curve analysis. Results: The image reconstruction time using the GPU was 196 times faster than the conventional reconstruction time using the CPU. For the four BURs, the area under curve values from the ROC curve were 0.6726 (A-region), 0.6890 (B-region), 0.7384 (C-region), and 0.8009 (D-region). Conclusions: The tomographic image using the prompt gamma ray event from the BNCT simulation was acquired using the GPU computation in order to perform a fast reconstruction during treatment. The authors verified the feasibility of the prompt gamma ray image reconstruction using the GPU computation for BNCT simulations

  1. High yield neutron generators using the DD reaction

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, J. H.; Harris, J. L.; Piestrup, M. A.; Gary, C. K.; Williams, D. L.; Apodaca, M. D.; Cremer, J. T. [Adelphi technology, 2003 E. Bayshore Rd. 94061, Redwood City, CA (United States); Ji, Qing; Ludewigt, B. A. [Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Jones, G. [G and J Enterprise, 1258 Quary Ln, Suite F, Pleasanton California 94566 (United States)

    2013-04-19

    A product line of high yield neutron generators has been developed at Adelphi technology inc. The generators use the D-D fusion reaction and are driven by an ion beam supplied by a microwave ion source. Yields of up to 5 Multiplication-Sign 10{sup 9} n/s have been achieved, which are comparable to those obtained using the more efficient D-T reaction. The microwave-driven plasma uses the electron cyclotron resonance (ECR) to produce a high plasma density for high current and high atomic ion species. These generators have an actively pumped vacuum system that allows operation at reduced pressure in the target chamber, increasing the overall system reliability. Since no radioactive tritium is used, the generators can be easily serviced, and components can be easily replaced, providing essentially an unlimited lifetime. Fast neutron source size can be adjusted by selecting the aperture and target geometries according to customer specifications. Pulsed and continuous operation has been demonstrated. Minimum pulse lengths of 50 {mu}s have been achieved. Since the generators are easily serviceable, they offer a long lifetime neutron generator for laboratories and commercial systems requiring continuous operation. Several of the generators have been enclosed in radiation shielding/moderator structures designed for customer specifications. These generators have been proven to be useful for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA) and fast neutron radiography. Thus these generators make excellent fast, epithermal and thermal neutron sources for laboratories and industrial applications that require neutrons with safe operation, small footprint, low cost and small regulatory burden.

  2. Database of prompt gamma rays from slow neutron capture for elemental analysis

    International Nuclear Information System (INIS)

    Firestone, R.B.; Choi, H.D.; Lindstrom, R.M.; Molnar, G.L.; Mughabghab, S.F.; Paviotti-Corcuera, R.; Revay, Zs; Trkov, A.; Zhou, C.M.; Zerkin, V.

    2004-01-01

    The increasing importance of Prompt Gamma-ray Activation Analysis (PGAA) in a broad range of applications is evident, and has been emphasized at many meetings related to this topic (e.g., Technical Consultants' Meeting, Use of neutron beams for low- and medium-flux research reactors: radiography and materials characterizations, IAEA Vienna, 4-7 May 1993, IAEA-TECDOC-837, 1993). Furthermore, an Advisory Group Meeting (AGM) for the Coordination of the Nuclear Structure and Decay Data Evaluators Network has stated that there is a need for a complete and consistent library of cold- and thermal neutron capture gamma ray and cross-section data (AGM held at Budapest,14-18 October 1996, INDC(NDS)-363); this AGM also recommended the organization of an IAEA CRP on the subject. The International Nuclear Data Committee (INDC) is the primary advisory body to the IAEA Nuclear Data Section on their nuclear data programs. At a biennial meeting in 1997, the INDC strongly recommended that the Nuclear Data Section support new measurements and update the database on Neutron-induced Prompt Gamma-ray Activation Analysis (21st INDC meeting, INDC/P(97)-20). As a consequence of the various recommendations, a CRP on ''Development of a Database for Prompt Gamma-ray Neutron Activation Analysis (PGAA)'' was initiated in 1999. Prior to this project, several consultants had defined the scope, objectives and tasks, as approved subsequently by the IAEA. Each CRP participant assumed responsibility for the execution of specific tasks. The results of their and other research work were discussed and approved by the participants in research co-ordination meetings (see Summary reports: INDC(NDS)-411, 2000; INDC(NDS)-424, 2001; and INDC(NDS)-443, 200). PGAA is a non-destructive radioanalytical method, capable of rapid or simultaneous ''in-situ'' multi-element analyses across the entire Periodic Table, from hydrogen to uranium. However, inaccurate and incomplete data were a significant hindrance in the

  3. The secondary neutron sources for generation of particular neutron fluxes

    International Nuclear Information System (INIS)

    Tracz, G.

    2007-07-01

    The foregoing paper presents the doctor's thesis entitled '' The secondary neutron sources for generation of particular neutron fluxes ''. Two secondary neutron sources have been designed, which exploit already existing primary sources emitting neutrons of energies different from the desired ones. The first source is devoted to boron-neutron capture therapy (BNCT). The research reactor MARIA at the Institute of Atomic Energy in Swierk (Poland) is the primary source of the reactor thermal neutrons, while the secondary source should supply epithermal neutrons. The other secondary source is the pulsed source of thermal neutrons that uses fast 14 MeV neutrons from a pulsed generator at the Institute of Nuclear Physics PAN in Krakow (Poland). The physical problems to be solved in the two mentioned cases are different. Namely, in order to devise the BNCT source the initial energy of particles ought to be increased, whilst in the other case the fast neutrons have to be moderated. Slowing down of neutrons is relatively easy since these particles lose energy when they scatter in media; the most effective moderators are the materials which contain light elements (mostly hydrogen). In order to increase the energy of neutrons from thermal to epithermal (the BNCT case) the so-called neutron converter should be exploited. It contains a fissile material, 235 U. The thermal neutrons from the reactor cause fission of uranium and fast neutrons are emitted from the converter. Then fissile neutrons of energy of a few MeV are slowed down to the required epithermal energy range. The design of both secondary sources have been conducted by means of Monte Carlo simulations, which have been carried out using the MCNP code. In the case of the secondary pulsed thermal neutron source, some of the calculated results have been verified experimentally. (author)

  4. Evaluation and measurement of prompt k0-factors to use in prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Goswami, A.; Nair, A.G.C.; Acharya, R.N.; Sudarshan, K.; Scindia, Y.M.; Reddy, A.V.R.; Manohar, S.B.

    2000-01-01

    The determination of experimental k 0 -factors is important due to uncertainties on absolute values of cross sections and prompt gamma-ray intensities. Determination of absolute full-energy peak detection efficiency and elemental sensitivity are required to obtain experimental k 0 -factor

  5. Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Staples, Parrish; Prettyman, Tom; Lestone, John

    1999-01-01

    We have used a Tomographic Gamma Scanner (TGS) to produce tomographic Prompt Gamma-Ray Neutron Activation Imaging of heterogeneous matrices [T.H. Prettyman, R.J. Estep, G.A. Sheppard, Trans. Am. Nucl. Soc. 69 (1993) 183-184]. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. We are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source to sample coupling term. To assist in the determination of the coupling term we have obtained images for a range of samples that are very well characterized; such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. We then compare the measurements to Monte Carlo N-particle calculations. For an accurate quantitative measurement it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes

  6. Measurement of total body chlorine by prompt gamma in vivo neutron activation analysis

    International Nuclear Information System (INIS)

    Beddoe, A.H.; Streat, S.J.; Hill, G.L.

    1987-01-01

    A method of measuring total body chlorine (TBCl) by prompt gamma in vivo neutron activation analysis is described depending on the same NaI(Tl) spectra used for determinations of total body nitrogen. Ratios of chlorine to hydrogen are derived and TBCl determined using a model of body composition depending on measured body weight, total body water (by tritium dilution) and protein (6.25 x nitrogen) as well as estimated body minerals and glycogen. The precision of the method based on scanning an anthropomorphic phantom is approximately 9% (SD), for a patient dose equivalent of less than 0.30 mSv. Spectra collected from 67 normal volunteers (32 male, 35 female) yielded mean values of TBCl of 72 +- 19 (SD) g in males and 53.6 +- 15 g in females, in broad agreement with values reported by workers using delayed gamma methods. Results are presented for two human cadavers analysed by neutron activation and conventional chemical analysis; the ratios of TBCl (neutron activation) to TBCl (chemical) were 0.980 +- 0.028 (SEM) and 0.91 +- 0.09. It is suggested that an improvement in precision will be achieved by increasing the scanning time (thereby increasing the radiation dose equivalent) and by adding two more detectors. (author)

  7. Imaging of heterogeneous materials by prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Staples, P.; Prettyman, T.; Lestone, J.

    1998-01-01

    The authors have used a tomographic gamma scanner (TGS) to produce tomographic prompt gamma-ray neutron activation analysis imaging (PGNAA) of heterogeneous matrices. The TGS was modified by the addition of graphite reflectors that contain isotopic neutron sources for sample interrogation. The authors are in the process of developing the analysis methodology necessary for a quantitative assay of large containers of heterogeneous material. This nondestructive analysis (NDA) technique can be used for material characterization and the determination of neutron assay correction factors. The most difficult question to be answered is the determination of the source-to-sample coupling term. To assist in the determination of the coupling term, the authors have obtained images for a range of sample that are very well characterized, such as, homogenous pseudo one-dimensional samples to three-dimensional heterogeneous samples. They then compare the measurements to MCNP calculations. For an accurate quantitative measurement, it is also necessary to determine the sample gamma-ray self attenuation at higher gamma-ray energies, namely pair production should be incorporated into the analysis codes

  8. Feasibility study of prompt gamma neutron activation for NDT measurement of moisture in stone and brick

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, R. A.; Al-Sheikhly, M. [Materials Science and Engineering Dept., U. of Maryland, College Park MD 20742 (United States); Grissom, C.; Aloiz, E. [Museum Conservation Institute, Smithsonian Institution, Washington DC 20746 (United States); Paul, R. [Chemical Sciences Division, NIST, Gaithersburg MD 20899 (United States)

    2014-02-18

    The conservation of stone and brick architecture or sculpture often involves damage caused by moisture. The feasibility of a NDT method based on prompt gamma neutron activation (PGNA) for measuring the element hydrogen as an indication of water is being evaluated. This includes systematic characterization of the lithology and physical properties of seven building stones and one brick type used in the buildings of the Smithsonian Institution in Washington, D.C. To determine the required dynamic range of the NDT method, moisture-related properties were measured by standard methods. Cold neutron PGNA was also used to determine chemically bound water (CBW) content. The CBW does not damage porous masonry, but creates an H background that defines the minimum level of detection of damaging moisture. The CBW was on the order of 0.5% for all the stones. This rules out the measurement of hygric processes in all of the stones and hydric processed for the stones with fine scale pore-size distributions The upper bound of moisture content, set by porosity through water immersion, was on the order of 5%. The dynamic range is about 10–20. The H count rates were roughly 1–3 cps. Taking into account differences in neutron energies and fluxes and sample volume between cold PGNA and a portable PGNA instrument, it appears that it is feasible to apply PGNA in the field.

  9. Optimization of combined delayed neutron and differential die-away prompt neutron signal detection for characterization of spent nuclear fuel assemblies

    International Nuclear Information System (INIS)

    Blanc, Pauline; Tobin, Stephen J.; Croft, Stephen; Menlove, Howard O.; Swinhoe, M.; Lee, T.

    2010-01-01

    The Next Generation Safeguards Initiative (NGSI) of the U.S. Department of Energy (DOE) has funded multiple laboratories and universities to develop a means to accurately quantify the Plutonium (Pu) mass in spent nuclear fuel assemblies and ways to also detect potential diversion of fuel pins. Delayed Neutron (DN) counting provides a signature somewhat more sensitive to 235 U than Pu while Differential Die-Away (DDA) is complementary in that it has greater sensitivity to Pu. The two methods can, with care, be combined into a single instrument which also provides passive neutron information. Individually the techniques cannot robustly quantify the Pu content but coupled together the information content in the signatures enables Pu quantification separate to the total fissile content. The challenge of merging DN and DDA, prompt neutron (PN) signal, capabilities in the same design is the focus of this paper. Other possibilities also suggest themselves, such as a direct measurement of the reactivity (multiplication) by either the boost in signal obtained during the active interrogation itself or by the extension of the die-away profile. In an early study, conceptual designs have been modeled using a neutron detector comprising fission chambers or 3He proportional counters and a ∼14 MeV neutron Deuterium-Tritium (DT) generator as the interrogation source. Modeling was performed using the radiation transport code Monte Carlo N-Particles eXtended (MCNPX). Building on this foundation, the present paper quantifies the capability of a new design using an array of 3 He detectors together with fission chambers to optimize both DN and PN detections and active characterization, respectively. This new design was created in order to minimize fission in 238 U (a nuisance DN emitter), to use a realistic neutron generator, to reduce the cost and to achieve near spatial interrogation and detection of the DN and PN, important for detection of diversion, all within the constraints of

  10. Critical concentrations of cadmium in human liver and kidney measured by prompt-gamma neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.H.; Vartsky, D.; Yasumura, S.; Zanzi, I.; Ellis, K.J.

    1979-01-01

    Few data exist on Cd metabolism in human beings. In particular, data are needed on the role of parameters such as age, sex, weight, diet, smoking habits, and state of health. Prompt-gamma neutron activation analysis (PGNAA) provides the only currently available means for measuring in vivo levels of liver and kidney Cd. The method employs an 85 Ci, 235 Pu,Be neutron source and a gamma ray detection system consisting of two Ge(Li) detector. The dose delivered to the liver and left kidney is 666 mrem (detection limit is 1.4 μg/g Cd in the liver and 2.0 mg Cd for one kidney). Absolute levels of Cd in the kidney and concentrations of Cd in the liver were measured in vivo in twenty healthy adult males using 238 Pu,Be neutron sources. Organ Cd levels of smokers were significantly elevated above those of nonsmokers. Biological half-time for Cd in the body was estimated to be 15.7 yr. Cigarette smoking was estimated to result in the absorption of 1.9 μg of Cd per pack. No relationship was bound between body stores of Cd (liver and kidney) and Cd or β-microglobulin levels in urine and blood. Currently the above neutron activation facility is being mounted on a 34-ft mobile trailer unit. This unit will be used to monitor levels of Cd in industrial workers. It is anticipated that critically important data, particularly on industrially exposed workers, will provide a better basis for determining critical concentrations and for the setting or revision of standards for industrial and environmental Cd pollution

  11. On-stream analysis of coal by prompt neutron activation analysis

    International Nuclear Information System (INIS)

    Barker, D.

    1981-01-01

    The need for rapid continuous on-stream analysis of coal was recognised in 1975. Analytical systems capable of determining some of the most important compositional properties of coal have been developed. The research programme has produced a series of analysers suitable for on-stream, batch, slurry and laboratory analytical determination of coal. This series of analysers is marketed under the name of 'Nucoalyzer'. The Nucoalyzer - CONAC (Continuous On-line Nuclear Analyzer for Coal) offers real-time, continuous determination of calorific value, percentage ash, percentage moisture, percentage sulphur, boiler fouling and slagging indices. The CONAC model is described in this article. The analytical principle employed in the various Nucoalyzer systems is based on prompt neutron activation analysis

  12. The optimization of gamma spectra processing in prompt gamma neutron activation analysis (PGNAA)

    Energy Technology Data Exchange (ETDEWEB)

    Pinault, Jean-Louis [IAEA Expert, 96 rue du Port David, 45370 Dry (France)], E-mail: jeanlouis_pinault@hotmail.fr; Solis, Jose [Instituto Peruano de Energia Nuclear, Av. Canada No. 1470, San Borja, Lima 41 (Peru)

    2009-04-15

    The uncertainty of the elemental analysis is one of the major factors governing the utility of on-line Prompt Gamma Neutron Activation Analysis (PGNAA) in the blending and sorting of bulk materials. In this paper, a general method applicable to Gamma spectra processing is presented and applied to PGNAA in mineral industry. Based on the Fourier transform of spectra and their de-correlation in the Fourier space (the improvement of the conditioning of the correlation matrix), processing of overlapping of characteristic peaks minimizes the propagation of random errors, which optimizes the accuracy and decreases the detection limits of elemental analyses. In comparison with classical methods based on the linear combinations of relevant regions of spectra the improvement may be considerable, especially when several elements are interfering. The method is applied to four case stories covering both borehole logging and on-line analysis on conveyor belt of raw materials.

  13. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kasviki, K. [Institute of Nuclear Technology and Radiation Protection, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece); Medical Physics Laboratory, Medical School, University of Ioannina, Ioannina 45110 (Greece); Stamatelatos, I.E. [Institute of Nuclear Technology and Radiation Protection, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece)], E-mail: ion@ipta.demokritos.gr; Yannakopoulou, E. [Institute of Physical Chemistry, NCSR ' Demokritos' , Aghia Paraskevi, Attikis 15310 (Greece); Papadopoulou, P. [Institute of Technology of Agricultural Products, NAGREF, Lycovrissi, Attikis 14123 (Greece); Kalef-Ezra, J. [Medical Physics Laboratory, Medical School, University of Ioannina, Ioannina 45110 (Greece)

    2007-10-15

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv.

  14. On the accuracy of protein determination in large biological samples by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Kasviki, K.; Stamatelatos, I.E.; Yannakopoulou, E.; Papadopoulou, P.; Kalef-Ezra, J.

    2007-01-01

    A prompt gamma neutron activation analysis (PGNAA) facility has been developed for the determination of nitrogen and thus total protein in large volume biological samples or the whole body of small animals. In the present work, the accuracy of nitrogen determination by PGNAA in phantoms of known composition as well as in four raw ground meat samples of about 1 kg mass was examined. Dumas combustion and Kjeldahl techniques were also used for the assessment of nitrogen concentration in the meat samples. No statistically significant differences were found between the concentrations assessed by the three techniques. The results of this work demonstrate the applicability of PGNAA for the assessment of total protein in biological samples of 0.25-1.5 kg mass, such as a meat sample or the body of small animal even in vivo with an equivalent radiation dose of about 40 mSv

  15. Elemental analysis of human placenta by neutron irradiation and gamma-ray spectrometry (standard, prompt and fast-neutron)

    International Nuclear Information System (INIS)

    Ward, N.I.

    1987-01-01

    Human placental tissue from 100 hospitalized deliveries were analysed for Ag, Al, As, Au, B, Ba, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, F, Fe, I, Hg, K, La, Mg, Mn, Mo, Na, Ni, Rb, S, Sb, Sc, Se, Sn, Sr, Ti, V, W and Zn using a combination of pre-chemical separation of sodium with hydrated antimony pentoxide and INAA. Boron and Si values were determined using prompt gamma-ray and fast-neutron techniques, respectively. Analysis of NBS-SRM Bovine Liver 1577 and a 'pooled standard' placental tissue for 33 elements showed a good agreement with most coefficients. Only Cd(-) and Zn(+) showed statistically significant correlations with birth weight, gestational age and placental weight. (author) 54 refs.; 3 tables

  16. Nuclear assay of coal. Volume 1. Coal composition by prompt neutron activation analysis: basic experiments. Final report

    International Nuclear Information System (INIS)

    Reynolds, G.; Bozorganesh, H.; Elias, E.; Gozani, T.; Maung, T.; Orphan, V.

    1979-01-01

    Using californium-252 as a source of exciting neutrons, prompt gamma photons emitted by elemental nuclei in the coal have been measured using several detectors, including sodium--iodide and germanium--lithium. Several coal types, including bituminous, subbituminous lignite and anthracite were crushed to various top sizes and analyzed carefully be traditional ASTM wet chemistry techniques at two or three different laboratories. The elements (sulfur, hydrogen, carbon, aluminum, silicon, iron, calcium, sodium, nitrogen, and chlorine) were determined by prompt neutron activations and the quantities compared with those of the wet chemical analyses

  17. Methodology for Quantitative Analysis of Large Liquid Samples with Prompt Gamma Neutron Activation Analysis using Am-Be Source

    International Nuclear Information System (INIS)

    Idiri, Z.; Mazrou, H.; Beddek, S.; Amokrane, A.

    2009-01-01

    An optimized set-up for prompt gamma neutron activation analysis (PGNAA) with Am-Be source is described and used for large liquid samples analysis. A methodology for quantitative analysis is proposed: it consists on normalizing the prompt gamma count rates with thermal neutron flux measurements carried out with He-3 detector and gamma attenuation factors calculated using MCNP-5. The relative and absolute methods are considered. This methodology is then applied to the determination of cadmium in industrial phosphoric acid. The same sample is then analyzed by inductively coupled plasma (ICP) method. Our results are in good agreement with those obtained with ICP method.

  18. Assessing neutron generator output using neutron activation of silicon

    International Nuclear Information System (INIS)

    Kehayias, Pauli M.; Kehayias, Joseph J.

    2007-01-01

    D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the 28 Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10 3 n/s/cm 2 ± 5%, which is consistent with the manufacturer's specifications

  19. Assessing neutron generator output using neutron activation of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Kehayias, Pauli M. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States); Kehayias, Joseph J. [Body Composition Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111 (United States)]. E-mail: joseph.kehayias@tufts.edu

    2007-08-15

    D-T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for neutron activation analysis, to study radiation damage to materials, to monitor the operation of the generator, and to measure radiation exposure. We describe a method for absolute neutron output and flux measurements of low output D-T neutron generators using delayed activation of silicon. We irradiated a series of silicon oxide samples with 14.1 MeV neutrons and counted the resulting gamma rays of the {sup 28}Al nucleus with an efficiency-calibrated detector. To minimize the photon self-absorption effects within the samples, we used a zero-thickness extrapolation technique by repeating the measurement with samples of different thicknesses. The neutron flux measured 26 cm away from the tritium target of a Thermo Electron A-325 D-T generator (Thermo Electron Corporation, Colorado Springs, CO) was 6.2 x 10{sup 3} n/s/cm{sup 2} {+-} 5%, which is consistent with the manufacturer's specifications.

  20. NEUTRON AND PHOTON DOSE MAPPING OF A DD NEUTRON GENERATOR.

    Science.gov (United States)

    Metwally, Walid A; Taqatqa, Osama A; Ballaith, Mohammed M; Chen, Allan X; Piestrup, Melvin A

    2017-11-01

    Neutron generators are an excellent tool that can be effectively utilized in educational institutions for applications such as neutron activation analysis, neutron radiography, and profiling and irradiation effects. For safety purposes, it is imperative that appropriate measures are taken in order to minimize the radiation dose from such devices to the operators, students and the public. This work presents the simulation and measurement results for the neutron and photon dose rates in the vicinity of the neutron generator installed at the University of Sharjah. A very good agreement is found between the simulated and measured dose rates. All of the public dose constraints were found to be met. The occupational dose constraint was also met after imposing a 200 cm no entry zone around the generator room. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Chlorine detection in fly ash concrete using a portable neutron generator.

    Science.gov (United States)

    Naqvi, A A; Kalakada, Zameer; Al-Matouq, Faris A; Maslehuddin, M; Al-Amoudi, O S B

    2012-08-01

    The chlorine concentration in chloride-contaminated FA cement concrete specimens was measured using a portable neutron generator based prompt gamma-ray neutron activation (PGNAA) setup with the neutron generator and the gamma-ray detector placed side-by-side on one side of the concrete sample. The minimum detectable concentration of chlorine in FA cement concrete measured in the present study was comparable with previous results for larger accelerator based PGNAA setup. It shows the successful application of a portable neutron generator in concrete corrosion studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Effect of fission dynamics on the spectra and multiplicities of prompt fission neutrons

    International Nuclear Information System (INIS)

    Nix, J.R.; Madland, D.G.; Sierk, A.J.

    1985-01-01

    With the goal of examining their effect on the spectra and multiplicities of the prompt neutrons emitted in fission, we discuss recent advances in a unified macroscopic-microscopic description of large-amplitude collective nuclear dynamics. The conversion of collective energy into single-particle excitation energy is calculated for a new surface-plus-window dissipation mechanism. By solving the Hamilton equations of motion for initial conditions appropriate to fission, we obtain the average fission-fragment translational kinetic energy and excitation energy. The spectra and multiplicities of the emitted neutrons, which depend critically upon the average excitation energy, are then calculated on the basis of standard nuclear evaporation theory, taking into account the average motion of the fission fragments, the distribution of fission-fragment residual nuclear temperature, the energy dependence of the cross section for the inverse process of compound-nucleus formation, and the possibility of multiple-chance fission. Some illustrative comparisons of our calculations with experimental data are shown

  3. Prompt gamma neutron activation analysis facility at the RA-6 research reactor

    International Nuclear Information System (INIS)

    Sanchez, F. A.; Calzetta, O

    2004-01-01

    A prompt gamma neutron activation activation analysis facility was developed at the 500 kw thermal power RA-6 research reactor of the Bariloche Atomic Center, Argentina.This facility consist of a radial beam port with external positioning of the sample.The gamma radiation is reduced by a bismuth filter placed inside the extraction tube and the beam diameter is limited by a set of two collimators up to 5 cm.The neutron flux at the sample position is 7 10 6 n/cm 2 s with a Cadmium ratio of 20/1.The gamma detector is a 50 % efficiency type p HPGe rounded by a NaI(Tl) for Compton suppressioning.The gamma spectra is measured through 0 to 8.5 MeV.The background have counting rate of 350 cps without sample. In this work is shown the efficiency curve, the calculed sensibilities and the lower detection limits for B, Cd, Sm, Gd, H, Cl, Hg, Eu, Ti, Ag, Au, Mo. The RA-6's PGNAA facility is fully working, although the analytic capacity is under improvement [es

  4. Compact neutron generator development and applications

    International Nuclear Information System (INIS)

    Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami; Lou, Tak-Pui

    2004-01-01

    The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to ∼100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper

  5. Measurement for skyshine of neutron generated by the K-600 neutron generator

    International Nuclear Information System (INIS)

    Zhen Huazhi; Li Guisheng; Wu Jingmin; Li Jianping

    1988-01-01

    The attenuation low of neutron scattering in atmosphere that generated by K-600 neutron generator at IMP was measured in order to evaluate the effect of the neutron generator to surroundings. The attenuation lenth λ = 396m was obtained and this result is in aggreement with the measured data at some laboratories abroad

  6. Compact neutron generator with nanotube ion source

    Science.gov (United States)

    Chepurnov, A. S.; Ionidi, V. Y.; Ivashchuk, O. O.; Kirsanov, M. A.; Kitsyuk, E. P.; Klenin, A. A.; Kubankin, A. S.; Nazhmudinov, R. M.; Nikulin, I. S.; Oleinik, A. N.; Pavlov, A. A.; Shchagin, A. V.; Zhukova, P. N.

    2018-02-01

    In this letter, we report the observation of fast neutrons generated when a positive acceleration potential is applied to an array of orientated carbon nanotubes, which are used as an ion source. The neutrons with energy of 2.45 MeV are generated as a result of D-D fusion reaction. The dependencies of the neutron yield on the value of the applied potential and residual pressure of deuterium are measured. The proposed approach is planned to be used for the development of compact neutron generators.

  7. Use of neutron-capture prompt gamma-ray activation analysis in environmental and energy research

    International Nuclear Information System (INIS)

    Gordon, G.E.

    1980-01-01

    Reactor-based neutron-capture prompt γ-ray activation analysis (PGAA) can be used for several trace elements (e.g., B, Cd, Sm, Gd), but it is mainly a major and minor element method. Among the 15 to 20 elements that can be determined in a particular type of sample, the major elements C, H, N and S can usually be measured in coals and biological samples and the elements of geochemical interest, Na, Al, Si, K, Ca, Ti, Fe and others in rocks, coal and other crustal samples. When used along with instrumental neutron activation analysis (INAA), the combined techniques can be used to analyze for 40 to 50 elements in crustal samples. Suggestions for further development of reactor-based PGAA include: the need to reduce low-energy γ-ray backgrounds for observations of species having intense lines only at low energy, more development of biological and special materials applications, the use of beam choppers to look for very short-lived species, and demonstrations of analyses of samples too large, precious or hazardous to be irradiated inside reactors. The greatest potential for applications of PGAA may be in the use of systems detached from reactors, i.e., those using 252 Cf or other isotopic neutron sources. This may be the only method for elemental analyses of large, inhomogeneous process streams in various industries, power plants, etc. Fluxes comparable to those of external beams from reactors are feasible with the use of mg quantitites of 252 Cf. Practical systems for use on coal have been developed. Many other applications would be possible: field prospecting for valuable ore deposits, studies of nutrients in soil and plants, in situ measurements in remote locations such as planetary surfaces, mines, bore holes, etc

  8. Prompt fissionγ-ray characteristics from neutron-induced fission on 239Pu and the time-dependence of prompt-γray emission

    Science.gov (United States)

    Gatera, Angélique; Göök, Alf; Hambsch, Franz-Josef; Moens, André; Oberstedt, Andreas; Oberstedt, Stephan; Sibbens, Goedele; Vanleeuw, David; Vidali, Marzio

    2018-03-01

    Recent years have seen an increased interest in prompt fission γ-ray (PFG) measurements motivated by a high priority request of the OECD/NEA for high precision data, mainly for the nuclear fuel isotopes 235U and 239Pu. Our group has conducted a PFG measurement campaign using state-of-the-art lanthanum halide detectors for all the main actinides to a precision better than 3%. The experiments were performed in a coincidence setup between a fission trigger and γ-ray detectors. The time-of-flight technique was used to discriminate photons, traveling at the speed of light, and prompt fission neutrons. For a full rejection of all neutrons below 20 MeV, the PFG time window should not be wider than a few nanoseconds. This window includes most PFG, provided that no isomeric states were populated during the de-excitation process. When isomeric states are populated, PFGs can still be emitted up to 1 yus after the instant of fission or later. To study these γ-rays, the detector response to neutrons had to be determined and a correction had to be applied to the γ-ray spectra. The latest results for PFG characteristics from the reaction 239Pu(nth,f) will be presented, together with an analysis of PFGs emitted up to 200 ns after fission in the spontaneous fission of 252Cf as well as for thermal-neutron induced fission on 235U and 239Pu. The results are compared with calculations in the framework of the Hauser-Feshbach Monte Carlo code CGMF and FIFRELIN.

  9. Development of a Portable Fusion Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Byung-Hoon; In, Sang-Ryul; Jin, Jeong-Tae; Chang, Dae-Sik; Jang, Doh-Yun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Cheol Ho [Hanyang Univ., Seoul (Korea, Republic of)

    2015-05-15

    For this purpose commercial ones, fast neutron yield from 10{sup 7} to 10{sup 11}, are supplied by several companies and research groups around the world. But internally the following limits make it difficult to develop the related application systems by domestic companies and/or research groups. - Limited life time - High price - Frequent trouble Not only to remove these limits but also to find out new internal application fields, it is necessary to develop our own domestic neutron generators. With the related technologies earned during fusion related researches, we did start to develop movable neutron generators from small one to big one, which could cover different fusion neutron yields. In this presentation the design and initial experimental results on the developed small neutron generator with a final target of 10{sup 8} n/s of 14 MeV neutrons, will be summarized.

  10. Neutron Generators Developed at LBNL for Homeland Security and Imaging Applications

    International Nuclear Information System (INIS)

    Reijonen, Jani

    2006-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented

  11. Compact Neutron Generators for Medical Home Land Security and Planetary Exploration

    International Nuclear Information System (INIS)

    Reijonen, J.

    2005-01-01

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented

  12. T-odd angular correlations in the emission of prompt gamma rays and neutrons in nuclear fission induced by polarized neutrons

    International Nuclear Information System (INIS)

    Danilyan, G. V.; Klenke, J.; Krakhotin, V. A.; Kopach, Yu. N.; Novitsky, V. V.; Pavlov, V. S.; Shatalov, P. B.

    2011-01-01

    Study of the T-odd three-vector correlation in the emission of prompt neutrons from 235 U fission by polarized cold neutrons has been continued at the facility MEPHISTO of the FRM II reactor (Technical University of Munich). The sought correlation was not found within experimental error of 2.3 × 10 −5 . The upper limit for the asymmetry coefficient has been set to vertical bar D n vertical bar −5 at 99% confidence level, whereas for ternary fission correlation coefficient D α = (170±20) × 10 −5 . This limit casts doubt on a model that explains the three-vector correlation in ternary fission by the Coriolis mechanism. At the same time, five-vector correlation in the emission of prompt fission neutrons has been measured, which describes the rotation of the fissioning nucleus at the moment it breaks (ROT effect). At the angle 22.5° to the fission axis, the correlation coefficient was found to be (1.57 ± 0.20) × 10 −4 , while at the angle of 67.5° it is zero within the experimental uncertainty. The existence of ROT effect in the emission of prompt fission neutrons can be explained by the anisotropy of neutron emission in the rest frame of the fragment (fission fragments are aligned with respect to the axis of deformation of the fissioning nucleus), similar to the mechanism of ROT effect in the emission of prompt γ-rays.

  13. New portable neutron generator for well logging

    International Nuclear Information System (INIS)

    Chicanov, A.E.; Gromov, E. V.; Gulko, V. M.; Izmailov, A. V.

    1994-01-01

    The information about the design, investigation and testing of new well neutron generator for the pulse neutron logging (PNL) is given in this paper. The main physical characteristics of new PNL apparatus are: Neutron flux 2.10 sup 8 n/s ; Pulse frequency>=400 Hz; Diameter= 90 mm; Logging velocity >200 m/h; Number of probes = 2; Resource > 300 h. The generator were provided by gas-filled neutron accelerative tube named NTF-2. The perspective of application and optimization shown PNL apparatus are considered. (author)

  14. Database of prompt gamma rays from slow neutron capture forelemental analysis

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, R.B.; Choi, H.D.; Lindstrom, R.M.; Molnar, G.L.; Mughabghab, S.F.; Paviotti-Corcuera, R.; Revay, Zs; Trkov, A.; Zhou,C.M.; Zerkin, V.

    2004-12-31

    The increasing importance of Prompt Gamma-ray ActivationAnalysis (PGAA) in a broad range of applications is evident, and has beenemphasized at many meetings related to this topic (e.g., TechnicalConsultants' Meeting, Use of neutron beams for low- andmedium-fluxresearch reactors: radiography and materialscharacterizations, IAEA Vienna, 4-7 May 1993, IAEA-TECDOC-837, 1993).Furthermore, an Advisory Group Meeting (AGM) for the Coordination of theNuclear Structure and Decay Data Evaluators Network has stated that thereis a need for a complete and consistent library of cold- and thermalneutron capture gammaray and cross-section data (AGM held at Budapest,14-18 October 1996, INDC(NDS)-363); this AGM also recommended theorganization of an IAEA CRP on the subject. The International NuclearData Committee (INDC) is the primary advisory body to the IAEA NuclearData Section on their nuclear data programmes. At a biennial meeting in1997, the INDC strongly recommended that the Nuclear Data Section supportnew measurements andupdate the database on Neutron-induced PromptGamma-ray Activation Analysis (21st INDC meeting, INDC/P(97)-20). As aconsequence of the various recommendations, a CRP on "Development of aDatabase for Prompt Gamma-ray Neutron Activation Analysis (PGAA)" wasinitiated in 1999. Prior to this project, several consultants had definedthe scope, objectives and tasks, as approved subsequently by the IAEA.Each CRP participant assumed responsibility for the execution of specifictasks. The results of their and other research work were discussed andapproved by the participants in research co-ordination meetings (seeSummary reports: INDC(NDS)-411, 2000; INDC(NDS)-424, 2001; andINDC(NDS)-443, 200). PGAA is a non-destructive radioanalytical method,capable of rapid or simultaneous "in-situ" multi-element analyses acrossthe entire Periodic Table, from hydrogen to uranium. However, inaccurateand incomplete data were a significant hindrance in the qualitative andquantitative

  15. Non destructive multi elemental analysis using prompt gamma neutron activation analysis techniques: Preliminary results for concrete sample

    Energy Technology Data Exchange (ETDEWEB)

    Dahing, Lahasen Normanshah [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia and Malaysian Nuclear Agency (Nuklear Malaysia), Bangi 43000, Kajang (Malaysia); Yahya, Redzuan [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Yahya, Roslan; Hassan, Hearie [Malaysian Nuclear Agency (Nuklear Malaysia), Bangi 43000, Kajang (Malaysia)

    2014-09-03

    In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. The system consists of collimated isotopic neutron source, Cf-252 with HPGe detector and Multichannel Analysis (MCA). Concrete with size of 10×10×10 cm{sup 3} and 15×15×15 cm{sup 3} were analysed as sample. When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively. The results obtained were compared with NAA and XRF techniques as a part of reference and validation. The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed.

  16. The Effects of Student Question-Generation with Online Prompts on Learning

    Science.gov (United States)

    Yu, Fu-Yun; Pan, Kuan-Jung

    2014-01-01

    The focus of this study was to investigate the effects of student-question generation with online prompts on student academic achievement, question-generation performance, learning satisfaction and learning anxiety. This study adopted a quasi-experimental research design. Two classes of eighth grade students (N = 64) from one middle school…

  17. Characteristics of a Portable Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jeong-Tae; Oh, Byung-Hoon; Chang, Dae-Sik; In, Sang-Yeol; Huh, Sung-Ryul; Hong, Kwang-Pyo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Neutron generators can be excellent tools for materials analysis, explosive material detection, nuclear weapon detection, and high quality radiography. D + D : 3He + n (2.5 MeV) D + T : 4He + n (14 MeV) Recent commercial neutron generators, fast neutron yield from 10{sup 7} to 10{sup 11} n/s, are produced by several companies and research groups around the world. But limited life time, high price, and frequent troubles make it difficult to develop related application systems by domestic companies or research groups. To remove such problems, it is necessary to develop our own domestic neutron generators. In this presentation, the design and experimental results on the developed small neutron generator are summarized. Experiments on deuterium beam extraction and fast neutron measurement by injecting deuterium beams on a drive-in target are executed. The stable deuterium beam of the energy higher than 100 keV was achieved by introducing metal cover which reduces the effect of metal-vacuum-insulator triple junction. The neutron flux of 5 n/s is measured by RadEye GN gamma Neutron (Thermo scientific) detector with about 200 mm distance and insertion of 40 mm PE plate between neutron source and the detector. The precise detector calibration is not carried out yet, so more detailed experimental results will be summarized at the presentation.

  18. Characteristics of a Portable Neutron Generator

    International Nuclear Information System (INIS)

    Jin, Jeong-Tae; Oh, Byung-Hoon; Chang, Dae-Sik; In, Sang-Yeol; Huh, Sung-Ryul; Hong, Kwang-Pyo

    2015-01-01

    Neutron generators can be excellent tools for materials analysis, explosive material detection, nuclear weapon detection, and high quality radiography. D + D : 3He + n (2.5 MeV) D + T : 4He + n (14 MeV) Recent commercial neutron generators, fast neutron yield from 10 7 to 10 11 n/s, are produced by several companies and research groups around the world. But limited life time, high price, and frequent troubles make it difficult to develop related application systems by domestic companies or research groups. To remove such problems, it is necessary to develop our own domestic neutron generators. In this presentation, the design and experimental results on the developed small neutron generator are summarized. Experiments on deuterium beam extraction and fast neutron measurement by injecting deuterium beams on a drive-in target are executed. The stable deuterium beam of the energy higher than 100 keV was achieved by introducing metal cover which reduces the effect of metal-vacuum-insulator triple junction. The neutron flux of 5 n/s is measured by RadEye GN gamma Neutron (Thermo scientific) detector with about 200 mm distance and insertion of 40 mm PE plate between neutron source and the detector. The precise detector calibration is not carried out yet, so more detailed experimental results will be summarized at the presentation

  19. Prompt gamma neutron activation analysis of toxic elements in radioactive waste packages

    Energy Technology Data Exchange (ETDEWEB)

    Ma, J.-L. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 St Paul-lez-Durance (France); Carasco, C., E-mail: cedric.carasco@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 St Paul-lez-Durance (France); Perot, B. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 St Paul-lez-Durance (France); Mauerhofer, E.; Kettler, J.; Havenith, A. [Institute of Energy and Climate Research - Nuclear Waste Management and Reactor Safety, Forschungszentrum Juelich GmbH (Germany)

    2012-07-15

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R and D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages. In particular, the amount of toxic elements present in radioactive waste packages must be assessed before they can be accepted in repository facilities in order to avoid pollution of underground water reserves. To this aim, the Nuclear Measurement Laboratory of CEA-Cadarache has started to study the performances of Prompt Gamma Neutron Activation Analysis (PGNAA) for elements showing large capture cross sections such as mercury, cadmium, boron, and chromium. This paper reports a comparison between Monte Carlo calculations performed with the MCNPX computer code using the ENDF/B-VII.0 library and experimental gamma rays measured in the REGAIN PGNAA cell with small samples of nickel, lead, cadmium, arsenic, antimony, chromium, magnesium, zinc, boron, and lithium to verify the validity of a numerical model and gamma-ray production data. The measurement of a {approx}20 kg test sample of concrete containing toxic elements has also been performed, in collaboration with Forschungszentrum Juelich, to validate the model in view of future performance studies for dense and large LL-MA waste packages. - Highlights: Black-Right-Pointing-Pointer Comparison between measurements and MCNP calculation has been performed for a PGNAA system. Black-Right-Pointing-Pointer The system aims at controlling the amount of toxic elements in nuclear waste. Black-Right-Pointing-Pointer Simple samples and a concrete cylinder in which impurities have been added are used. Black-Right-Pointing-Pointer Calculations agree within a factor 2 with measurements. Black-Right-Pointing-Pointer The system can be improved with a better neutron flux monitoring and the use of boron-free graphite.

  20. Neutron Generators for Spent Fuel Assay

    International Nuclear Information System (INIS)

    Ludewigt, Bernhard A.

    2010-01-01

    The Next Generation Safeguards Initiative (NGSI) of the U.S. DOE has initiated a multi-lab/university collaboration to quantify the plutonium (Pu) mass in, and detect the diversion of pins from, spent nuclear fuel (SNF) assemblies with non-destructive assay (NDA). The 14 NDA techniques being studied include several that require an external neutron source: Delayed Neutrons (DN), Differential Die-Away (DDA), Delayed Gammas (DG), and Lead Slowing-Down Spectroscopy (LSDS). This report provides a survey of currently available neutron sources and their underlying technology that may be suitable for NDA of SNF assemblies. The neutron sources considered here fall into two broad categories. The term 'neutron generator' is commonly used for sealed devices that operate at relatively low acceleration voltages of less than 150 kV. Systems that employ an acceleration structure to produce ion beam energies from hundreds of keV to several MeV, and that are pumped down to vacuum during operation, rather than being sealed units, are usually referred to as 'accelerator-driven neutron sources.' Currently available neutron sources and future options are evaluated within the parameter space of the neutron generator/source requirements as currently understood and summarized in section 2. Applicable neutron source technologies are described in section 3. Commercially available neutron generators and other source options that could be made available in the near future with some further development and customization are discussed in sections 4 and 5, respectively. The pros and cons of the various options and possible ways forward are discussed in section 6. Selection of the best approach must take a number of parameters into account including cost, size, lifetime, and power consumption, as well as neutron flux, neutron energy spectrum, and pulse structure that satisfy the requirements of the NDA instrument to be built.

  1. Neutronics activities for next generation devices

    International Nuclear Information System (INIS)

    Gohar, Y.

    1985-01-01

    Neutronic activities for the next generation devices are the subject of this paper. The main activities include TFCX and FPD blanket/shield studies, neutronic aspects of ETR/INTOR critical issues, and neutronics computational modules for the tokamak system code and tandem mirror reactor system code. Trade-off analyses, optimization studies, design problem investigations and computational models development for reactor parametric studies carried out for these activities are summarized

  2. Monte Carlo simulation of the scattered component of neutron capture prompt gamma-ray analyzer responses

    International Nuclear Information System (INIS)

    Jin, Y.; Verghese, K.; Gardner, R.P.

    1986-01-01

    This paper describes a major part of our efforts to simulate the entire spectral response of the neutron capture prompt gamma-ray analyzer for bulk media (or conveyor belt) samples by the Monte Carlo method. This would allow one to use such a model to augment or, in most cases, essentially replace experiments in the calibration and optimum design of these analyzers. In previous work, we simulated the unscattered gamma-ray intensities, but would like to simulate the entire spectral response as we did with the energy-dispersive x-ray fluorescence analyzers. To accomplish this, one must account for the scattered gamma rays as well as the unscattered and one must have available the detector response function to translate the incident gamma-ray spectrum calculated by the Monte Carlo simulation into the detected pulse-height spectrum. We recently completed our work on the germanium detector response function, and the present paper describes our efforts to simulate the entire spectral response by using it with Monte Carlo predicted unscattered and scattered gamma rays

  3. A Preliminary Study on Detecting Fake Gold Bars Using Prompt Gamma Activation Analysis: Simulation of Neutron Transmission in Gold Bar

    International Nuclear Information System (INIS)

    Lee, K. M.; Sun, G. M.

    2016-01-01

    The purpose of this study is to develop fake gold bar detecting method by using Prompt-gamma activation analysis (PGAA) facility at the Korea Atomic Energy Research Institute (KAERI). PGAA is an established nuclear analytical technique for non-destructive determination of elemental and isotopic compositions. For a preliminary study on detecting fake gold bar, Monte Carlo simulation of neutron transmission in gold bar was conducted and the possibility for detecting fake gold bar was confirmed. Under the gold bullion standard, it guaranteed the government would redeem any amount of currency for its value in gold. After the gold bullion standard ended, gold bars have been the target for investment as ever. But it is well known that fake gold bar exist in the gold market. This cannot be identified easily without performing a testing as it has the same appearance as the pure gold bar. In order to avoid the trading of fake gold bar in the market, they should be monitored thoroughly. Although the transmissivity of cold neutrons are low comparing that of thermal neutrons, the slower neutrons are more apt to be absorbed in a target, and can increase the prompt gamma emission rate. Also the flux of both thermal and cold neutron beam is high enough to activate thick target. If the neutron beam is irradiated on the front and the reverse side of gold bar, all insides of it can be detected

  4. A Preliminary Study on Detecting Fake Gold Bars Using Prompt Gamma Activation Analysis: Simulation of Neutron Transmission in Gold Bar

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. M.; Sun, G. M. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    The purpose of this study is to develop fake gold bar detecting method by using Prompt-gamma activation analysis (PGAA) facility at the Korea Atomic Energy Research Institute (KAERI). PGAA is an established nuclear analytical technique for non-destructive determination of elemental and isotopic compositions. For a preliminary study on detecting fake gold bar, Monte Carlo simulation of neutron transmission in gold bar was conducted and the possibility for detecting fake gold bar was confirmed. Under the gold bullion standard, it guaranteed the government would redeem any amount of currency for its value in gold. After the gold bullion standard ended, gold bars have been the target for investment as ever. But it is well known that fake gold bar exist in the gold market. This cannot be identified easily without performing a testing as it has the same appearance as the pure gold bar. In order to avoid the trading of fake gold bar in the market, they should be monitored thoroughly. Although the transmissivity of cold neutrons are low comparing that of thermal neutrons, the slower neutrons are more apt to be absorbed in a target, and can increase the prompt gamma emission rate. Also the flux of both thermal and cold neutron beam is high enough to activate thick target. If the neutron beam is irradiated on the front and the reverse side of gold bar, all insides of it can be detected.

  5. New generation non-stationary portable neutron generators for biophysical applications of Neutron Activation Analysis.

    Science.gov (United States)

    Marchese, N; Cannuli, A; Caccamo, M T; Pace, C

    2017-01-01

    Neutron sources are increasingly employed in a wide range of research fields. For some specific purposes an alternative to existing large-scale neutron scattering facilities, can be offered by the new generation of portable neutron devices. This review reports an overview for such recently available neutron generators mainly addressed to biophysics applications with specific reference to portable non-stationary neutron generators applied in Neutron Activation Analysis (NAA). The review reports a description of a typical portable neutron generator set-up addressed to biophysics applications. New generation portable neutron devices, for some specific applications, can constitute an alternative to existing large-scale neutron scattering facilities. Deuterium-Deuterium pulsed neutron sources able to generate 2.5MeV neutrons, with a neutron yield of 1.0×10 6 n/s, a pulse rate of 250Hz to 20kHz and a duty factor varying from 5% to 100%, when combined with solid-state photon detectors, show that this kind of compact devices allow rapid and user-friendly elemental analysis. "This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo". Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Neutron flux stabilization in the NG-150 neutron generators

    International Nuclear Information System (INIS)

    Kuz'min, L.E.; Makarov, S.A.; Pronman, I.M.

    1986-01-01

    Problem of metal tritium target lifetime increase and neutron flux stabilization in the NG-150 neutron generators is studied. Possibility on neutron flux stabilization using the mass analyzer for low-angle (4 deg and 41 deg) mass separation of a beam in thre components, which fall on a target simultaneously, is confirmed experimentally. Basic generator parameters are: accelerating voltage of 150 kV, total beam current on a target of 1.5 mA, beam current density of 0.3-1.6 mA/cm 2 , beam diameter of 8 mm. The initial neutron flux on the targets of 0.73 mg/cm 2 thick constituted 1.1x10 11 ssup(-1). The neutron flux monitoring was accomplished from recoil proton recording by a plastic scintillator. Flux decrease by more than 5% served as a signel for measuring mass analyzer magnetic field providing beam displacement on a target and restoration of the given flux. The NG-150 generator neutron flux stabilization was attained during 2h

  7. The intense neutron generator study

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1966-07-01

    The study has confirmed that a beam of 65 mA of protons at 1000 MeV, striking a molten lead-bismuth target surrounded by heavy water moderator, would give the desired flux of 10{sup 16} thermal neutrons per cm{sup 2} per second to provide intense beams of neutrons and also to produce radioisotopes. The proton beam passing through a thin auxiliary target would also produce beams of mesons. The design and construction of the ion source, injector, accelerator, target and auxiliaries present challenging technical problems. Moreover, continued development for improved life and economy promises to be rewarding. The high neutron intensity is sought for research in solid and liquid state physics and also for nuclear physics. Participation by universities and industry, both in development and use, is expected to be extensive. (author)

  8. The intense neutron generator study

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1966-01-01

    The study has confirmed that a beam of 65 mA of protons at 1000 MeV, striking a molten lead-bismuth target surrounded by heavy water moderator, would give the desired flux of 10 16 thermal neutrons per cm 2 per second to provide intense beams of neutrons and also to produce radioisotopes. The proton beam passing through a thin auxiliary target would also produce beams of mesons. The design and construction of the ion source, injector, accelerator, target and auxiliaries present challenging technical problems. Moreover, continued development for improved life and economy promises to be rewarding. The high neutron intensity is sought for research in solid and liquid state physics and also for nuclear physics. Participation by universities and industry, both in development and use, is expected to be extensive. (author)

  9. Investigation of Response of Several Neutron Surveymeters by a DT Neutron Generator

    International Nuclear Information System (INIS)

    Kim, Sang In; Jang, In Su; Kim, Jang Lyul; Lee, Jung IL; Kim, Bong Hwan

    2012-01-01

    Several neutron measuring devices were tested under the neutron fields characterized with two distinct kinds of thermal and fast neutron spectrum. These neutron fields were constructed by the mixing of both thermal neutron fields and fast neutron fields. The thermal neutron field was constructed using by a graphite pile with eight AmBe neutron sources. The fast neutron field of 14 MeV was made by a DT neutron generator. In order to change the fraction of fast neutron fluence rate in each neutron fields, a neutron generator was placed in the thermal neutron field at 50 cm and 150 cm from the reference position. The polyethylene neutron collimator was used to make moderated 14 MeV neutron field. These neutron spectra were measured by using a Bonner sphere system with an LiI scintillator, and dosimetric quantities delivered to neutron surveymeters were determined from these measurement results.

  10. Neutron generator tube ion source control

    International Nuclear Information System (INIS)

    Bridges, J.R.

    1982-01-01

    A system is claimed for controlling the output of a neutron generator tube of the deuterium-tritium accelerator type and having an ion source to produce sharply defined pulses of neutrons for well logging use. It comprises: means for inputting a relatively low voltage input control pulse having a leading edge and a trailing edge; means, responsive to the input control pulse, for producing a relatively high voltage ion source voltage pulse after receipt of the input pulse; and means, responsive to the input control pulse, for quenching, after receipt of the input pulse, the ion source control pulse, thereby providing a sharply time defined neutron output from the generator tube

  11. Calibration of A Prompt Gamma Neutron Activation Analysis (PGNAA) Facility: Experience at the Oregon State University TRIGA Reactor

    International Nuclear Information System (INIS)

    Norlida Yussup

    2011-01-01

    A prompt gamma neutron activation analysis (PGNAA) facility at Oregon State University (OSU) TRIGA reactor has been built in year 2008 and been operated since then. PGNAA is a technique used to determine the presence and quantity of trace elements such as boron, hydrogen and carbon which are more difficult to detect with other neutron analysis method. A calibration is essential to ensure the system works as required and the output is valid and reliable. The calibration was carried out by using Standard Reference Material (SRM). Besides, background data was also acquired for comparisons and analysis. The results are analyzed and discussed in this paper. (author)

  12. Prompt neutron fission spectrum mean energies for the fissile nuclides and 252Cf

    International Nuclear Information System (INIS)

    Holden, N.E.

    1985-01-01

    The international standard for a neutron spectrum is that produced from the spontaneous fission of 252 Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, 233 U, 235 U, 239 Pu, and 241 Pu are of interest from the standpoint of nuclear reactors. The average neutron energies of these spectra are tabulated. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Also tabulated are the measurements of the ratio of mean energies for pairs of fission neutron spectra. 75 refs., 9 tabs

  13. Development of a database for prompt γ-ray neutron activation analysis: Summary report of the third research coordination meeting

    International Nuclear Information System (INIS)

    Lindstrom, Richard M.; Firestone, Richard B.; Paviotti-Corcuera, R.

    2003-01-01

    The main discussions and conclusions from the Third Co-ordination Meeting on the Development of a Database for Prompt Gamma-ray Neutron Activation Analysis are summarized in this report. All results were reviewed in detail, and the final version of the TECDOC and the corresponding software were agreed upon and approved for preparation. Actions were formulated with the aim of completing the final version of the TECDOC and associated software by May 2003

  14. Development of a database for prompt γ-ray neutron activation analysis. Summary report of the second research coordination meeting

    International Nuclear Information System (INIS)

    Lone, M.A.; Mughabghab, S.F.; Paviotti-Corcuera, R.

    2001-06-01

    This report summarizes the presentations, recommendations and conclusions of the Second Research Co-ordination Meeting on Development of a Database for Prompt γ-ray Neutron Activation Analysis. The purpose of this meeting was to review results achieved on the development of the database, discuss further developments and planning of the products ol this CRP. Actions to be taken were agreed upon with the aim to complete the project by the end of 2002. (author)

  15. Development of a database for prompt γ-ray neutron activation analysis. Summary report of the third research coordination meeting

    International Nuclear Information System (INIS)

    Lindstorm, Richard M.; Firestone, Richard B.; Paviotti-Corcuera, R.

    2003-04-01

    The main discussions and conclusions from the Third Co-ordination Meeting on the Development of a Database for Prompt γ-ray Neutron Activation Analysis are summarised in this report. All results were reviewed in detail, and the final version of the TECDOC and the corresponding software were agreed upon and approved for preparation. Actions were formulated with the aim of completing the final version of the TECDOC and associated software by May 2003. (author)

  16. Reevaluation of the average prompt neutron emission multiplicity (nubar) values from fission of uranium and transuranium nuclides

    International Nuclear Information System (INIS)

    Holden, N.E.; Zucker, M.S.

    1984-01-01

    In response to a need of the safeguards community, we have begun an evaluation effort to upgrade the recommended values of the prompt neutron emission multiplicity distribution, P/sub nu/ and its average value, nubar. This paper will report on progress achieved thus far. The evaluation of the uranium, plutonium, americium and curium nuclide's nubar values will be presented. The recommended values will be given and discussed. 61 references

  17. Delayed neutron fraction and prompt decay constant measurement in the MINERVE reactor using the PSI instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Perret, Gregory [Paul Scherrer Institute, Villigen, 5232, (Switzerland)

    2015-07-01

    The critical decay constant (B/A), delayed neutron fraction (B) and generation time (A) of the Minerve reactor were measured by the Paul Scherrer Institut (PSI) and the Commissariat a l'Energie Atomique (CEA) in September 2014 using the Feynman-alpha and Power Spectral Density neutron noise measurement techniques. Three slightly subcritical configuration were measured using two 1-g {sup 235}U fission chambers. This paper reports on the results obtained by PSI in the near critical configuration (-2g). The most reliable and precise results were obtained with the Cross-Power Spectral Density technique: B = 708.4±9.2 pcm, B/A = 79.0±0.6 s{sup -1} and A 89.7±1.4 micros. Predictions of the same kinetic parameters were obtained with MCNP5-v1.6 and the JEFF-3.1 and ENDF/B-VII.1 nuclear data libraries. On average the predictions for B and B/A overestimate the experimental results by 5% and 11%, respectively. The discrepancy is suspected to come from either a corruption of the data or from the inadequacy of the point kinetic equations to interpret the measurements in the Minerve driven system. (authors)

  18. 10 CFR 39.55 - Tritium neutron generator target sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  19. Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

    Science.gov (United States)

    Neudecker, Denise; Talou, Patrick; Kahler, Albert C.; White, Morgan C.; Kawano, Toshihiko

    2017-09-01

    We present an evaluation of the 235U prompt fission neutron spectrum (PFNS) induced by thermal to 20-MeV neutrons. Experimental data and associated covariances were analyzed in detail. The incident energy dependence of the PFNS was modeled with an extended Los Alamos model combined with the Hauser-Feshbach and the exciton models. These models describe prompt fission, pre-fission compound nucleus and pre-equilibrium neutron emissions. The evaluated PFNS agree well with the experimental data included in this evaluation, preliminary data of the LANL and LLNL Chi-Nu measurement and recent evaluations by Capote et al. and Rising et al. However, they are softer than the ENDF/B-VII.1 (VII.1) and JENDL-4.0 PFNS for incident neutron energies up to 2 MeV. Simulated effective multiplication factors keff of the Godiva and Flattop-25 critical assemblies are further from the measured keff if the current data are used within VII.1 compared to using only VII.1 data. However, if this work is used with ENDF/B-VIII.0β2 data, simulated values of keff agree well with the measured ones.

  20. Neutron generator instrumentation at the Department 2350 Neutron Generator Test Facility

    International Nuclear Information System (INIS)

    Bryant, T.C.; Mowrer, G.R.

    1979-06-01

    The computer and waveform digitizing capability at the test facility has allowed several changes in the techniques used to test neutron generators. These changes include methods used to calibrate the instrumentation and changes in the operation of the test facility. These changes have increased the efficiency of the test facility as well as increasing both timing and amplitude accuracy of neutron generator waveforms

  1. Status of prompt gamma neutron activation analysis (PGAA) at TRR-1/M1 (Thai Research Reactor-1/Modified 1)

    International Nuclear Information System (INIS)

    Asvavijnijkulchai, Chanchai; Dharmavanij, Wanchai; Siangsanan, Pariwat; Ratanathongchai, Wichian; Chongkum, Somporn

    1999-01-01

    The first prompt gamma activation analysis (PGAA) was designed, constructed and installed at a 6 inch diameter neutron beam port of the Thai Research Reactor-1/Modified 1 (TRR-1/M1) since 1989. Beam characteristic were made by Gd foil irradiation, X-ray film exposing and densitometry scanning consequently. The thermal neutron flux at sample position was measured by Au foil activation, and was about 1 x 10 7 n.cm 2 .sec -1 at 700 kW operating power. The experiments have been conducted successfully. In 1998, the PGAA facility has been developed for the reactor operating power at 1.2 MW. The new PGAA system, e.g., beam shutter, gamma collimator and biological shields have been designed to reduce the leakage of neutrons and gamma radiation to the acceptance levels in accordance with the International Commission on Radiation Protection Publication 60 (ICRP 60). The construction and installation will be completed in April 1999. (author)

  2. The statistical model calculation of prompt neutron spectra from spontaneous fission of {sup 244}Cm and {sup 246}Cm

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimenko, B.F. [V.G. Khlopin Radium Inst., Saint Peterburg (Russian Federation)

    1997-03-01

    The calculations of integral spectra of prompt neutrons of spontaneous fission of {sup 244}Cm and {sup 246}Cm were carried out. The calculations were done by the Statistical Computer Code Complex SCOFIN applying the Hauser-Feschbach method as applied to the description of the de-excitation of excited fission fragments by means of neutron emission. The emission of dipole gamma-quanta from these fragments was considered as a competing process. The average excitation energy of a fragment was calculated by two-spheroidal model of tangent fragments. The density of levels in an excited fragment was calculated by the Fermi-gas model. The quite satisfactory agreement was reached between theoretical and experimental results obtained in frames of Project measurements. The calculated values of average multiplicities of neutron number were 2,746 for {sup 244}Cm and 2,927 for {sup 246}Cm that was in a good accordance with published experimental figures. (author)

  3. Vertical distribution of elements in non-polluted estuarine sediments determined by neutron induced prompt gamma-ray and instrumental neutron activation analyses

    International Nuclear Information System (INIS)

    Kuno, A.; Sampei, K.; Matsuo, M.; Sawahata, H.

    1999-01-01

    Neutron induced prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA) have been applied to the sediments collected from the Yasaka River estuary in Oita Prefecture, Japan. The vertical distribution of 33 elements in the sediments has been determined and compared with that in more polluted estuarine sediments. While the S content increased with increasing depth because of a sulphide accumulation under reducing condition, the increase in sulphide-forming elements such as Ag, Cd, Co and Zn was not observed in the deeper section of the Yasaka River estuarine sediments. (author)

  4. Production of 14 MeV neutrons from D-D neutron generators

    International Nuclear Information System (INIS)

    Cecil, F.E.; Nieschmidt, E.B.

    1986-01-01

    The production of 14 MeV neutrons from a D-D neutron generator resulting from tritium buildup from the d(d,p)t reaction in the target is discussed. The effect of the 14 MeV neutrons on fast neutron activation analysis with D-D neutron generators is evaluated. (orig.)

  5. Fast neutron activation analysis by means of low voltage neutron generator

    Directory of Open Access Journals (Sweden)

    M.E. Medhat

    Full Text Available A description of D-T neutron generator (NG is presented. This machine can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. Procedure of neutron flux determination and efficiency calculation is described. Examples of testing some Egyptian natural cosmetics are given. Keywords: Neutron generator, Fast neutron activation analysis, Elemental analysis

  6. Engineering design of a neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Daniel M.; Campos, Tarcísio P.R. de, E-mail: dmcoelho.eng@gmail.com, E-mail: tprcampos@pq.cnpq.br [Universidade Federal de Minas Gerais (NRI/UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear. Nucleo de Radiações Ionizantes

    2017-07-01

    This paper presents an engineering design of a neutron generator (NG). In order to analyze and choose the materials and the appropriate geometry, previous studies of NRI Group (Nucleus for Ionizing Radiation at UFMG - NRI/UFMG) were considered and a model was developed for the simulation of these systems. The efficiency of a neutron generator is measured by the neutron flux. Among the modeling and simulation methods, was employed open software sources for the transmuting cell, aiming to evaluate resonant cavity and for complementary physical analysis. In addition, the titanium target was compared designed based in other studies of NRI Group. Deuterium plasma with a density close to 10{sup 10} particles/cm³, was proposed with a frequency of 0.898 GHz and an approximate wavelength of 110 μm, using a radio frequency antenna up to 2.45 GHz. This compact system includes a hydrogen-isotopes fusor, moderator, reflector and shield. Neutron reflection minimized the neutron escape, increasing the final flux. A insulation material is required to enclose the device. As a conclusion, the investigated nuclear and electromagnetic features of NG have demonstrated that such generator shall have a notable potential for radioisotope generation applied to medical diagnosis. The designs presented will be used to build a 3D model in the NRI laboratory and then a prototype with the selected materials. (author)

  7. Digitizing and analysis of neutron generator waveforms

    International Nuclear Information System (INIS)

    Bryant, T.C.

    1977-11-01

    All neutron generator waveforms from units tested at the SLA neutron generator test site are digitized and the digitized data stored in the CDC 6600 tape library for display and analysis using the CDC 6600 computer. The digitizing equipment consists mainly of seven Biomation Model 8100 transient recorders, Digital Equipment Corporation PDP 11/20 computer, RK05 disk, seven-track magnetic tape transport, and appropriate DEC and SLA controllers and interfaces. The PDP 11/20 computer is programmed in BASIC with assembly language drivers. In addition to digitizing waveforms, this equipment is used for other functions such as the automated testing of multiple-operation electronic neutron generators. Although other types of analysis have been done, the largest use of the digitized data has been for various types of graphical displays using the CDC 6600 and either the SD4020 or DX4460 plotters

  8. Plasma driven neutron/gamma generator

    Science.gov (United States)

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  9. Gas target neutron generator studies

    International Nuclear Information System (INIS)

    Chatoorgoon, V.

    1978-01-01

    The need for an intense neutron source for the study of radiation damage on materials has resulted in the proposal of various solid, liquid, and gas targets. Among the gas targets proposed have been the transonic gas target, two types of hypersonic gas target, and the subsonic gas target (SGT). It has been suggested that heat deposition in a subsonic channel might create a gas density step which would constitute an attractive gas target type. The first part of the present study examines this aspect of the SGT and shows that gas density gradients are indeed formed by heat deposition in subsonic flow. The variation of beam voltage, gas density, gas pressure, and gas temperature within the channel have been calculated as functions of the system parameters: beam voltage, beam current, channel diameter, stagnation tank temperature and pressure. The analysis is applicable to any beam particle and target gas. For the case of T + on D 2 , which is relevant to the fusion application, the 14 MeV neutron profiles are presented as a function of system parameters. It is found that the SGT is compatible with concentrated intense source operation. The possibility of instability was investigated in detail using a non-linear analysis which made it possible to follow the complete time development of the SGT. It was found that the SGT is stable against all small perturbations and certain types of large perturbations. It appears that the SGT is the most advantageous type of gas target, operating at a lower mass flow and less severe stagnation tank conditions than the other types. The second part of the thesis examines a problem associated with the straight hypersonic target, the deuterium spill into the tritium port. The regime of practical operation for this target is established. (auth)

  10. Neutron generator (HIRRAC) and dosimetry study.

    Science.gov (United States)

    Endo, S; Hoshi, M; Takada, J; Tauchi, H; Matsuura, S; Takeoka, S; Kitagawa, K; Suga, S; Komatsu, K

    1999-12-01

    Dosimetry studies have been made for neutrons from a neutron generator at Hiroshima University (HIRRAC) which is designed for radiobiological research. Neutrons in an energy range from 0.07 to 2.7 MeV are available for biological irradiations. The produced neutron energies were measured and evaluated by a 3He-gas proportional counter. Energy spread was made certain to be small enough for radiobiological studies. Dose evaluations were performed by two different methods, namely use of tissue equivalent paired ionization chambers and activation of method with indium foils. Moreover, energy deposition spectra in small targets of tissue equivalent materials, so-called lineal energy spectrum, were also measured and are discussed. Specifications for biological irradiation are presented in terms of monoenergetic beam conditions, dose rates and deposited energy spectra.

  11. Neutron generator based on adiabatic trap

    International Nuclear Information System (INIS)

    Golovin, I.N.; Zhil'tsov, V.A.; Panov, D.A.; Skovoroda, A.A.; Shatalov, G.E.; Shcherbakov, A.G.

    1988-01-01

    A possibility of 14 MeV neutron generator (NG) production on the basis of axial-symmetric adiabatic trap with MHD cusped armature for the testing of materials and elements of the DT reactor first wall and blanket structure is discussed. General requirements to NG are formulated. It is shown that the NG variant discussed meets the requirements formulated. Approximate calculation of the NG parameters has shown that total energy consumption by the generator does not exceed 220 MW at neutron flux specific capacity of 2.5 MW/m 2 and radiation test area of 5-6 m 2

  12. Spatial and temporal mapping of 10B distrubtion in vivo using nuclear reactor-based prompt gamma neutron activation analysis and image reconstruction techniques. Final Report

    International Nuclear Information System (INIS)

    Jacquelyn Yanch

    2006-01-01

    This project involved the development of a method for in vivo prompt gamma neutron activation analysis for the investigation of Boron-10 distribution in a rabbit knee. The overall objective of this work was a robust approach for rapid screening of new 10 B-labelled compounds to determine their suitability for use in the treatment of rheumatoid arthritis via Boron Neutron Capture Synovectomy (BNCS). For BNCS it is essential to obtain a compound showing high uptake levels in the synovium and long residence time in the joints. Previously the in vivo uptake behavior of potential compounds was evaluated in the arthritic knee joints of rabbits via extensive dissection studies. These studies are very labor-intensive and involve sacrificing large numbers of animals. An in vivo 10 B screening approach was developed to provide initial evaluation of potential compounds. Only those compounds showing positive uptake and retention characteristics will be evaluated further via dissection studies. No further studies will be performed with compounds showing rapid clearance and/or low synovial uptake. Two approaches to in vivo screening were investigated using both simulation methods and experimentation. Both make use of neutron beams generated at the MIT Research Reactor. The first, Transmission Computed Tomography (TCT) was developed and tested but was eventually rejected due to very limited spatial resolution using existing reactor beams. The second, in vivo prompt gamma neutron activation analysis (IVPGNAA) was much more promising. IVPGNAA was developed using computer simulation and physical measurement coupled with image reconstruction techniques. The method was tested in arthritic New Zealand rabbits previously injected intra-articularly with three boron labeled compounds and shown to be effective in providing information regarding uptake level and residence time of 10 B in the joint

  13. Differential and integral comparisons of three representations of the prompt neutron spectrum for the spontaneous fission of 252Cf

    International Nuclear Information System (INIS)

    Madland, D.G.; LaBauve, R.J.; Nix, J.R.

    1984-01-01

    Because of their importance as neutron standards, we present comparisons of measured and calculated prompt fission neutron spectra N(E) and average prompt neutron multiplicities anti nu/sub p/ for the spontaneous fission of 252 Cf. In particular, we test three representations of N(E) against recent experimental measurements of the differential spectrum and threshold integral cross sections. These representations are the Maxwellian spectrum, the NBS spectrum, and the Los Alamos spectrum of Madland and Nix. For the Maxwellian spectrum, we obtain the value of the Maxwellian temperature T/sub M/ by a least-squares adjustment to the experimental differential spectrum of Poenitz and Tamura. For the Los Alamos spectrum, a similar least-squares adjustment determines the nuclear level-density parameter a, which is the single unknown parameter that appears. The NBS spectrum has been previously constructed by adjustments to eight differential spectra measured during the period 1965 to 1974. Among these three representations, we find that the Los Alamos spectrum best reproduces both the differential and integral measurements, assuming ENDF/B-V cross sections in the calculation of the latter. Although the NBS spectrum reproduces the integral measurements fairly well, it fails to satisfactorily reproduce the new differential measurement, and the Maxwellian spectrum fails to satisfactorily reproduce the integral measurements. Additionally, we calculate a value of anti nu/sub p/ from the Los Alamos theory that is within approximately 1% of experiment. 25 references

  14. Energies and Yields of Prompt Gamma Rays from Fragments in Slow-Neutron Induced Fission of 235U

    Energy Technology Data Exchange (ETDEWEB)

    Albinsson, H [Chalmers Univ. of Technology, Goeteborg (SE)

    1971-04-15

    Measurements were made on the gamma radiation emitted from fission fragments in slow-neutron induced fission of 235U. The fragments were detected with solid state detectors of the surface barrier type and the gamma radiation with a Nal(Tl) scintillator. Mass selection was used so that the gamma radiation could be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. In this way it was possible to select various collimator settings and let gamma radiation of different half-lives be enhanced. Gamma-ray energy spectra from these time components were then recorded as function of mass. The spectrum shape differed greatly depending on the half-life of the radiation and the fragment from which it was emitted. The results of the present measurements were discussed in the light of existing fission models, and comparisons were made with prompt gamma-ray and neutron data from other fission experiments

  15. Development of a database for prompt γ-ray neutron activation analysis. Summary report of the first research coordination meeting

    International Nuclear Information System (INIS)

    Paviotti-Corcuera, R.; Lindstrom, R.M.

    2000-02-01

    This report summarizes the presentations, recommendations and conclusions of the First Research Co-ordination Meeting on Development of a Database for Prompt γ-ray Neutron Activation Analysis. Neutron-capture Prompt γ-ray Activation Analysis (PGAA) is a non-destructive radioanalytical method, capable of rapid or in-situ simultaneous multielement analysis of many elements of the Periodic Table, from hydrogen to uranium, in the same sample. Inaccuracy and incompleteness of the data available for use in PGAA are a significant handicap in the qualitative and quantitative analysis of capture-gamma spectra. The goal of this CRP is to replace the twenty-year-old data from a single laboratory with something fundamentally new: an evaluated database which includes a combination of evaluated nuclear physics data, physical theory, and recent measurements. The resulting database will be comparable in quality with that for radioactive decay. In addition, more accurate values of neutron capture cross-sections and γ-ray intensities that result from this database will improve the accuracy of radiation shielding calculations. (author)

  16. Energies and Yields of Prompt Gamma Rays from Fragments in Slow-Neutron Induced Fission of 235U

    International Nuclear Information System (INIS)

    Albinsson, H.

    1971-04-01

    Measurements were made on the gamma radiation emitted from fission fragments in slow-neutron induced fission of 235 U. The fragments were detected with solid state detectors of the surface barrier type and the gamma radiation with a Nal(Tl) scintillator. Mass selection was used so that the gamma radiation could be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. In this way it was possible to select various collimator settings and let gamma radiation of different half-lives be enhanced. Gamma-ray energy spectra from these time components were then recorded as function of mass. The spectrum shape differed greatly depending on the half-life of the radiation and the fragment from which it was emitted. The results of the present measurements were discussed in the light of existing fission models, and comparisons were made with prompt gamma-ray and neutron data from other fission experiments

  17. Effects of sample and spectrum characteristics on cold and thermal neutron prompt gamma activation analysis in environmental studies of plants

    International Nuclear Information System (INIS)

    Robinson, L.; Zhao, L.

    2009-01-01

    Previous studies including the development of methods for the determination of carbon, nitrogen, and phosphorus in cattail using cold neutron prompt gamma activation (CNPGAA) and thermal neutron prompt gamma activation analysis (TNPGAA); evaluation of the precision and accuracy of these methods through the analysis of Standard Reference Materials (SRMs); and comparison of the sensitivity of CNPGAA to TNPGAA have been done in the CNPGAA and TNPGAA facilities at the National Institute of Standards and Technology (NIST). This paper integrates the findings from all of these prior studies and presents recommendations for the application of CNPGAA and TNPGAA in environmental studies of plants based on synergistic considerations of the effects of neutron energy, matrix factors such as chlorine content, Compton scattering, hydrogen content, sample thickness, and spectral interferences from Cl on the determination of C, N, and P. This paper also provides a new approach that simulates a sensitivity curve for an element of interest (S), which is a function of hydrogen content (X) and sample thickness (Y) as follows: S = aX + bY + c (where a, b, and c are constants). This approach has provided more accurate results from the analysis of SRMs than traditional methods and an opportunity to use models to optimize experimental conditions. (author)

  18. Secondary electron ion source neutron generator

    Science.gov (United States)

    Brainard, John P.; McCollister, Daryl R.

    1998-01-01

    A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

  19. Production of a pulseable fission-like neutron flux using a monoenergetic 14 MeV neutron generator and a depleted uranium reflector

    Science.gov (United States)

    Koltick, D.; McConchie, S.; Sword, E.

    2008-04-01

    The design and performance of a pulseable neutron source utilizing a D-T neutron generator and a depleted uranium reflector are presented. Approximately half the generator's 14 MeV neutron flux is used to produce a fission-like neutron spectrum similar to 252Cf. For every 14 MeV neutron entering the reflector, more than one fission-like neutron is reflected back across the surface of the reflector. Because delayed neutron production is more than two orders of magnitude below the prompt neutron production, the source takes full advantage of the generator's pulsed mode capability. Applications include all elemental characterization systems using neutron-induced gamma-ray spectroscopy. The source simultaneously emits 14 MeV neutrons optimal to excite fast neutron-induced gamma-ray signals, such as from carbon and oxygen, and fission-like neutrons optimal to induce neutron capture gamma-ray signals, such as from hydrogen, nitrogen, and chlorine. Experiments were performed, which compare well to Monte Carlo simulations, showing that the uranium reflector enhances capture signals by up to a factor of 15 compared to the absence of a reflector.

  20. The Prompt Fission Neutron Spectrum: From Experiment to the Evaluated Data and its Impact on Critical Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Rising, Michael Evan [Los Alamos National Laboratory

    2015-06-10

    After a brief introduction concerning nuclear data, prompt fission neutron spectrum (PFNS) evaluations and the limited PFNS covariance data in the ENDF/B-VII library, and the important fact that cross section uncertainties ~ PFNS uncertainties, the author presents background information on the PFNS (experimental data, theoretical models, data evaluation, uncertainty quantification) and discusses the impact on certain well-known critical assemblies with regard to integral quantities, sensitivity analysis, and uncertainty propagation. He sketches recent and ongoing research and concludes with some final thoughts.

  1. Utilization of a pulsed D-T neutron generator

    International Nuclear Information System (INIS)

    Vilaithong, T.; Singkarat, S.; Tippawan, U.

    2000-01-01

    In the past two decades the IAEA has supported the establishment of neutron laboratories in many developing countries by providing small D-T neutron generators. The neutron generator is basically a low energy (100-400 keV) ion accelerator capable of producing a continuous beam of deuterons with a current in the range between 1-2.5 mA. These neutron generators are primarily intended to be used for fast neutron activation analysis. This paper describes the utilization of a 14 MeV neutron generator in continuous and pulsed beam modes in applied neutron physics program at Chiang Mai University. (author)

  2. Analysis of marine samples by neutron-induced prompt gamma-ray technique and ICP-MS

    International Nuclear Information System (INIS)

    Yonezawa, C.; Matsue, H.; McKay, K.; Povinec, P.

    2001-01-01

    Multi-element and isotopic analyses of oils and marine environmental samples were carried out to estimate a contamination source using a 'finger printing' method. Elemental analyses were carried out using neutron-induced prompt gamma-ray analysis (PGA), instrumental neutron activation analysis (INAA) at the Japan Atomic Institute, Tokai-mura, Japan (JAERI) and ICP-MS in the IAEA Marine Environment Laboratory, Monaco (MEL). Fifteen elements including light elements, H, B, N, Si and Ca, which cannot be determined by INAA and ICP-MS, were determined by PGA. A total of 47 elements were determined in the present study. The potential of PGA for the determination of isotopic ratios was tested by measuring 34 S/ 32 S ratios in oils. The evaluation of historical records of marine environmental conditions using annual bands in coral samples was also investigated. (author)

  3. Development of multielement neutron-capture prompt γ-rays activation analysis method

    International Nuclear Information System (INIS)

    Liu Yuren; Xie Yali; Zhao Yunzhi; Liu Jiping; Meng Bonian

    1998-01-01

    The relationship between content of the measured elements and area of typical peaks of prompt γ-rays is presented. The root-mean square errors on both the regression value of instrumentation analysis and chemical analysis for some common elements are lower than 0.5wt%. Function of the slowing body was found and analysis sensitivity was enhanced obviously in the iron ore analysis. The FWHM of the spectrometer for the H prompt γ-ray peak (2.223 MeV) is 3 keV

  4. Characterization of Deuteron-Deuteron Neutron Generators

    Science.gov (United States)

    Waltz, Cory Scott

    A facility based on a next-generation, high-flux D-D neutron generator (HFNG) was commissioned at the University of California Berkeley. The characterization of the HFNG is presented in the following study. The current generator design produces near mono-energetic 2.45 MeV neutrons at outputs of 108 n/s. Calculations provided show that future conditioning at higher currents and voltages will allow for a production rate over 1010 n/s. Characteristics that effect the operational stability include the suppression of the target-emitted back streaming electrons, target sputtering and cooling, and ion beam optics. Suppression of secondary electrons resulting from the deuterium beam striking the target was achieved via the implementation of an electrostatic shroud with a voltage offset of greater than -400 V relative to the target. Ion beam optics analysis resulted in the creation of a defocussing extraction nozzle, allowing for cooler target temperatures and a more compact design. To calculate the target temperatures, a finite difference method (FDM) solver incorporating the additional heat removal effects of subcooled boiling was developed. Validation of the energy balance results from the finite difference method calculations showed the iterative solver converged to heat removal results within about 3% of the expected value. Testing of the extraction nozzle at 1.43 mA and 100 kV determined that overheating of the target did not occur as the measured neutron flux of the generator was near predicted values. Many factors, including the target stopping power, deuterium atomic species, and target loading ratio, affect the flux distribution of the HFNG neutron generator. A detailed analysis to understand these factors effects is presented. Comparison of the calculated flux of the neutron generator using deuteron depth implantation data, neutron flux distribution data, and deuterium atomic species data matched the experimentally calculated flux determined from indium foil

  5. Measuring hydrogen by cold-neutron prompt-gamma activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, R M; Paul, R L; Greenberg, R R [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Div. of Inorganic Analytical Research; Vincent, D H [Michigan Univ., Ann Arbor, MI (United States). Dept. of Nuclear Engineering

    1994-05-01

    By irradiating with cold neutrons and avoiding hydrogenous materials of construction, a PGAA instrument was developed at the Cold Neutron Research Facility at NIST with hydrogen detection limits in the microgram range in many materials. Quantities of 5-10 [mu]g H/g are presently measurable in gram-sized samples of silicon or quartz, and of order 0.01 wt % can be quantitatively measured in complex silicate rocks. (author) 19 refs.; 1 fig.; 1 tab.

  6. Study on Neutron Generation by Using Modified Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In-Jung; Kim, Suk-Kwon; Park, Chang-Su; Jung, Nam-Suk; Jung, Hwa-Dong; Chung, Kyoung-Jae; Hwang, Yong-Seok; Choi, H. D.

    2006-01-01

    The effects of Ti target thickness and deuteron beam energy on neutron generation in the modified prototype DD neutron generator were studied. Three kinds of Ti targets with the thickness of 10 μm, 40 μm and 1 mm were used. Deuteron beam energy was varied from 45 keV to 65 keV. The effects of target thickness and deuteron beam energy were evaluated for every set of experimental run and the results were discussed

  7. Survey of Neutron Generators for Active Interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Moss, Calvin Elroy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, William L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sundby, Gary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johnson, James P. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-05-02

    Some of these commercially available generators meet all of the requirements in Table 1, but there are other concerns. Most generators containing SF6 will be required to have the SF6 gas removed for shipping because of DOT regulations. However, Thermo Fisher has a DOT exemption. The P211 and B211 from Thermo Fisher meet the requirements listed in Table 1, but they are old designs and are no longer offered for sale. Also, they require 15 minutes or more of warmup before neutron output is available, and they lack a modern digital control. The nGen-300C from Starfire Industries is interesting because it is a portable system, but it uses the DD reaction for 2.5 MeV neutrons, which are not as penetrating as the 14 MeV neutrons from the DT reaction. The MP 320 from Thermo Fisher is another portable system, but the minimum pulse rate is 250 Hz, which is too fast for measurement of delayed neutrons and re-interrogation by delayed neutrons between pulses. The Genie 16 from Sodern (from France) probably meets the requirements, but the required power is probably too high for battery operation. The generators from Russia and China may be difficult to purchase, and service may not be available. The power required by some of these generators is low enough that batteries can be used. The portable units, nGen-300C and the MP320, could easily be operated with batteries. Other generators with low power requirements, as specified in the above vendors list, could possibly be operated with reason size batteries. The batteries do not need to be internal to the generator, but can be in a separate package. The availability of high capacity lithium batteries with sophisticated safety circuits makes battery operation more possible now than when lead acid batteries were used. The best path forward probably requires working with vendors of the existing systems. If Starfire Industries could be persuaded to put tritium in their nGen-300C generator, possibly in collaboration with a national

  8. TU-FG-BRB-07: GPU-Based Prompt Gamma Ray Imaging From Boron Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S; Suh, T; Yoon, D; Jung, J; Shin, H; Kim, M [The catholic university of Korea, Seoul (Korea, Republic of)

    2016-06-15

    Purpose: The purpose of this research is to perform the fast reconstruction of a prompt gamma ray image using a graphics processing unit (GPU) computation from boron neutron capture therapy (BNCT) simulations. Methods: To evaluate the accuracy of the reconstructed image, a phantom including four boron uptake regions (BURs) was used in the simulation. After the Monte Carlo simulation of the BNCT, the modified ordered subset expectation maximization reconstruction algorithm using the GPU computation was used to reconstruct the images with fewer projections. The computation times for image reconstruction were compared between the GPU and the central processing unit (CPU). Also, the accuracy of the reconstructed image was evaluated by a receiver operating characteristic (ROC) curve analysis. Results: The image reconstruction time using the GPU was 196 times faster than the conventional reconstruction time using the CPU. For the four BURs, the area under curve values from the ROC curve were 0.6726 (A-region), 0.6890 (B-region), 0.7384 (C-region), and 0.8009 (D-region). Conclusion: The tomographic image using the prompt gamma ray event from the BNCT simulation was acquired using the GPU computation in order to perform a fast reconstruction during treatment. The authors verified the feasibility of the prompt gamma ray reconstruction using the GPU computation for BNCT simulations.

  9. Feasibility of using prompt neutron capture gamma rays to detect mercury

    International Nuclear Information System (INIS)

    Bell, Z.W.

    1993-10-01

    This report describes a study to determine the feasibility to use neutrons to probe hidden spaces within buildings for the presence of mercury. The study was performed in four phases: First a search of the scientific literature was performed to ascertain the behavior of mercury subsequent to the capture of a thermal or near-thermal neutron. Second, a Monte Carlo investigation (using the code MCNP) of the effects of neutrons on materials expected to be found near and/or surrounding the mercury was undertaken. Third, a Monte Carlo study of the shielding and beam forming properties of various configurations of moderator material was started. Lastly, a Monte Carlo analysis of a likely field situation involving mercury behind 1 inch and 2 inch thicknesses of concrete was performed

  10. X-Ray Measurements Of A Thermo Scientific P385 DD Neutron Generator

    International Nuclear Information System (INIS)

    Wharton, C. J.; Seabury, E. H.; Chichester, D. L.; Caffrey, A. J.; Simpson, J.; Lemchak, M.

    2011-01-01

    Idaho National Laboratory is experimenting with electrical neutron generators, as potential replacements for californium-252 radioisotopic neutron sources in its PINS prompt gamma-ray neutron activation analysis (PGNAA) system for the identification of military chemical warfare agents and explosives. In addition to neutron output, we have recently measured the x-ray output of the Thermo Scientific P385 deuterium-deuterium neutron generator. X rays are a normal byproduct from neutron generators, but depending on their intensity and energy, x rays can interfere with gamma rays from the object under test, increase gamma-spectrometer dead time, and reduce PGNAA system throughput. The P385 x-ray energy spectrum was measured with a high-purity germanium (HPGe) detector, and a broad peak is evident at about 70 keV. To identify the source of the x rays within the neutron generator assembly, it was scanned by collimated scintillation detectors along its long axis. At the strongest x-ray emission points, the generator also was rotated 60 deg. between measurements. The scans show the primary source of x-ray emission from the P385 neutron generator is an area 60 mm from the neutron production target, in the vicinity of the ion source. Rotation of the neutron generator did not significantly alter the x-ray count rate, and its x-ray emission appears to be axially symmetric. A thin lead shield, 3.2 mm (1/8 inch) thick, reduced the 70-keV generator x rays to negligible levels.

  11. Determination of boron in borosilicate glasses by neutron capture prompt gamma-ray activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Jr, J E; Lindstrom, R M

    1987-01-01

    Major levels of boron in borosilicate glasses were determined nondestructively by neutron activation analysis. The effects of neutron self-shielding by boron (1 to 8% by weight) are examined. Results of the analysis of a series of glasses with increasing boron composition are 1.150 +- .005% and 7.766 +- .035% for the low and high members of the series. Once analyzed, the glasses are useful as secondary standards for alpha track counting, and also ion and electron microprobe analyses of glasses. 12 refs.; 3 tables.

  12. Neutron generator power supply modeling in EMMA

    International Nuclear Information System (INIS)

    Robinson, A.C.; Farnsworth, A.V.; Montgomery, S.T.; Peery, J.S.; Merewether, K.O.

    1996-01-01

    Sandia National Laboratories has prime responsibility for neutron generator design and manufacturing, and is committed to developing predictive tools for modeling neutron generator performance. An important aspect of understanding component performance is explosively driven ferroelectric power supply modeling. EMMA (ElectroMechanical Modeling in ALEGRA) is a three dimensional compile time version of Sandia's ALEGRA code. The code is built on top of the general ALEGRA framework for parallel shock-physics computations but also includes additional capability for modeling the electric potential field in dielectrics. The overall package includes shock propagation due to explosive detonation, depoling of ferroelectric ceramics, electric field calculation and coupling with a general lumped element circuit equation system. The AZTEC parallel iterative solver is used to solve for the electric potential. The DASPK differential algebraic equation package is used to solve the circuit equation system. Sample calculations are described

  13. Status of prompt gamma neutron activation analysis (PGAA) at TRR-1/M1 (Thai Research Reactor-1/Modified 1)

    Energy Technology Data Exchange (ETDEWEB)

    Asvavijnijkulchai, Chanchai; Dharmavanij, Wanchai; Siangsanan, Pariwat; Ratanathongchai, Wichian; Chongkum, Somporn [Physics Division, Office of Atomic Energy for Peace, Vibhavadi Rangsit Road, Chatuchak, Bangkok (Thailand)

    1999-08-01

    The first prompt gamma activation analysis (PGAA) was designed, constructed and installed at a 6 inch diameter neutron beam port of the Thai Research Reactor-1/Modified 1 (TRR-1/M1) since 1989. Beam characteristic were made by Gd foil irradiation, X-ray film exposing and densitometry scanning consequently. The thermal neutron flux at sample position was measured by Au foil activation, and was about 1 x 10{sup 7} n.cm{sup 2}.sec{sup -1} at 700 kW operating power. The experiments have been conducted successfully. In 1998, the PGAA facility has been developed for the reactor operating power at 1.2 MW. The new PGAA system, e.g., beam shutter, gamma collimator and biological shields have been designed to reduce the leakage of neutrons and gamma radiation to the acceptance levels in accordance with the International Commission on Radiation Protection Publication 60 (ICRP 60). The construction and installation will be completed in April 1999. (author)

  14. Development of a D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Jung, Hwa Dong; Park, Chang Su; Jung, Nam Suk; Jung, Soon Wook; Hwang, Y. S.; Choi, H. D.

    2007-01-01

    To enhance neutron yield, the ion source of the D-D neutron generator is replaced by a large current helicon plasma ion source. Current and energy of deuteron beam are increased, and hence neutron yield is enhanced. The maximum neutron yield is 2x10 8 n/s

  15. Proposed Brookhaven accelerator-based neutron generator

    International Nuclear Information System (INIS)

    Grand, P.; Batchelor, K.; Chasman, R.; Rheaume, R.

    1976-01-01

    The d-Li Neutron Source concept, which includes a high-current dueteron linac, is an outgrowth of attempts made to use the BNL, 200-MeV proton linac BLIP facility to do radiation damage studies. It included a 100 mA, 30-MeV deuteron linear accelerator and a fast-flowing liquid lithium jet as the target. The latest design is not very different, except that the current is now 200 mA and the linac energy has been raised to 35 MeV. Both parameters, were changed to optimize the effectiveness of the facility with respect to flux, experimental volume and match to 14 MeV neutron-radiation-damage effects. The proposed Brookhaven Accelerator-based Neutron Generator is described with particular emphasis on the linear accelerator. The proposed facility is a practical and efficient way of producing the intense, high energy neutron beams needed for CTR material studies. The accelerator and liquid-metal technologies are well proven, state-of-the-art technologies. The fact that no new technology is required guarantees the possibility of meeting construction schedules, and more importantly, guarantees a high level of operational reliability

  16. Neutron PSDs for the next generation of spallation neutron sources

    CERN Document Server

    Eijk, C W

    2002-01-01

    A review of R and D for neutron PSDs to be used at anticipated new spallation neutron sources: the Time-of-Flight system facility, European Spallation Source, Spallation Neutron Source and Neutron Arena, is presented. The gas-filled detectors, scintillation detectors and hybrid systems are emphasized.

  17. Neutron generators and their uses in research and applied fields. Vol. 1

    Energy Technology Data Exchange (ETDEWEB)

    Asfour, F I [Division of Basic Nuclear Sciences, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt)

    1996-03-01

    The development of the low voltage neutron generators (NGS) has contributed considerably to the scope of nuclear research and the economical application of nuclear methods. Such simple instruments are used to produce 14 MeV and 3 MeV neutrons via the 3{sup H}(d,n)4{sup H}e and 2{sup H}(d,n)3{sup H}e reactions,respectively. The neutrons are very widely used and are inexpensive, easy to install and operate, therefore, in addition to nuclear physicists, there are a number of groups of scientists who use low voltage accelerators as tools for pure and applied research, service and education. The aim of this work is to review shortly those problems and methods of science and technology where the neutrons produced in the D-T and D-D reactions play the main role. A wide range of experiments with the detection of neutrons and charged particles is available including the study of shielding and the generator technology itself. N.G. are recently widely used for the determination of neutron data needed for fast reactor and thermonuclear devices. The principles and techniques of the possible uses of neutron generators in technology and research are summarized. The review is devoted to:- Give a short review of the most important operational characteristics of the neutron generators and the necessary instruments needed for application. Outline the main applications of the neutron generators in neutron activation and prompt radiation analysis in various fields(metallurgy, chemistry, biology, meteoritic and lunar studies, geology and mining, etc...) fast neutron therapy, and radiation effects. 2 figs.

  18. Design of a facility by neutron activation by spectrometry of prompt gamma

    International Nuclear Information System (INIS)

    Oliver, R.; Benites L, S.; Montoya Z, M.

    1993-01-01

    We show the basic design of the facility of PGNAA that we will install in the hall of the peruvian reactor RP-10. The thermal neutron flux (without a gamma filter) will be 2,0 x 10 8 n/cm -2 s -1 at 10 MW of power. The ratio of gamma exposition without gamma filter will be 29 kR/h. (authors). 8 refs., 2 figs

  19. Feasibility study of application of Prompt Gamma Neutron Activation Analysis (PGNAA) method in TRIGA IPR-R1 reactor

    International Nuclear Information System (INIS)

    Guerra, Bruno Teixeira

    2016-01-01

    The TRIGA Mark I IPR-R1 research reactor is located at Nuclear Technology Development Centre (CDTN), Brazilian Commission for Nuclear Energy (CNEN), in Belo Horizonte, Brazil. The reactor operates at 100 kW but the core configuration allows the increasing of the power up to 250 kW. It has been applied research, training and radioisotopes production. The establishment of the Prompt Gamma Neutron Activation Analysis (PGNAA) method at the TRIGA IPR-R1 reactor will significantly increase the types of matrices analysed as well as the number of chemical elements. Additionally it will complement the neutron activation analysis. This work presents a proposed design of a PGNAA facility to be installed at the TRIGA IPR-R1. The proposed design is based on a tube as a neutron guide from the reactor core, inside the reactor pool, 6 m below the room’s level where shall be located the rack containing the set sample/detector/shielding. Thus, the aim of this study is to verify the feasibility to establish the PGNAA method in IPR-R1 through theoretical study applying the Monte Carlo code. The feasibility of establishing the PGAA method at the IPR-R1 installations was evaluated through of the calculations of neutron flux, radioactive capture reaction rates and detection limits for some isotopes. According to the obtained results, it can be concluded that is possible to establish the PGAA method at the IPR-R1 reactor, even with some restrictions in its theoretical design calculated by MCNP. (author)

  20. Modeling Taylor series approximations for prompt neutron kinetics with lab view simulations

    International Nuclear Information System (INIS)

    Adzri, E. P.

    2012-09-01

    The reactor point kinetics equations have been subjected to intense research in an effort to find simple yet accurate numerical solutions methods. The equations are very stiff numerically, meaning that there is a wide variation in the decay constants, so that using a particular time step in the numerical solution may provide sufficient accuracy for the group, but not for another. Several solutions techniques have been presented on the point kinetics equations with varying degrees of complexity. These include Power Series Solutions, CORE, PCA, Genapol and Taylor series methods. In this research, algorithms were developed based on the first and second order Taylor series expansion and simulated in LabVIEW to solve the Reactor Point Kinetics equations using block diagram nodes implemented within stacked sequences. The algorithms developed were fast,accurate and simple to code. Several reactivity insertions were used to simulate the change in neutron population with time. The LabVIEW- Taylor series solutions were compared with other solution techniques such as Power Series Solutions, CORE, PCA, Genapol and McMahon and Pierson's Taylor series approximation. The results of LabVIEW-Taylor series technique used by McMahon and Pearson The LabVIEW-implemented techniques were found to agree very well with these other methods. At 1x10 -8 s the neutron population was 1.000220 neutrons / cm 3 , at 1 x 10 -2 s it was 2.007681 neutrons / cm 3 and at 1x10 -1 s it was 2.075317 neutrons / cm 3 ; same results reported by Genapol for a fast reactor, it produced good and accurate results and compared very favorably with other methods found in the literature. Using much smaller time steps to the order or 10 -8 s commensurate with fast reactor parameters also produced very satisfactory results, indicating that the LabVIEW-based Taylor series technique is suitable for simulating the kinetics of fast reactors as well as thermal reactors. Algorithms developed that included second order terms

  1. Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

    International Nuclear Information System (INIS)

    English, G.A.; Firestone, R.B.; Perry, D.L.; Reijonen, J.P.; Ka-Ngo Leung; Garabedian, G.F.; Molnar, G.L.; Revay, Zs.

    2008-01-01

    Without quality historical records that provide the composition of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclear-analytical methods, most importantly, gamma-spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, prompt gamma activation analysis (PGAA) provides a 'single-shot' in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents. Additionally, neutron activation analysis (NAA) using short-lived activation products complements PGAA and is especially useful when NAA activation surpasses the PGAA in elemental sensitivity. (author)

  2. Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

    International Nuclear Information System (INIS)

    Firestone, Richard B; English, G.A.; Firestone, R.B.; Perry, D.L.; Reijonen, J.P.; Leung, Ka-Ngo; Garabedian, G.F.; Molnar, G.L.; Revay, Zs.

    2008-01-01

    Without quality historical records that provide the composition of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclear-analytical methods, most importantly, gamma-spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, prompt gamma activation analysis (PGAA) provides a 'single-shot' in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents.1-3. Additionally, neutron activation analysis (NAA) using short-lived activation products complements PGAA and is especially useful when NAA activation surpasses the PGAA in elemental sensitivity

  3. D-D neutron generator development at LBNL.

    Science.gov (United States)

    Reijonen, J; Gicquel, F; Hahto, S K; King, M; Lou, T-P; Leung, K-N

    2005-01-01

    The plasma and ion source technology group in Lawrence Berkeley National Laboratory is developing advanced, next generation D-D neutron generators. There are three distinctive developments, which are discussed in this presentation, namely, multi-stage, accelerator-based axial neutron generator, high-output co-axial neutron generator and point source neutron generator. These generators employ RF-induction discharge to produce deuterium ions. The distinctive feature of RF-discharge is its capability to generate high atomic hydrogen species, high current densities and stable and long-life operation. The axial neutron generator is designed for applications that require fast pulsing together with medium to high D-D neutron output. The co-axial neutron generator is aimed for high neutron output with cw or pulsed operation, using either the D-D or D-T fusion reaction. The point source neutron generator is a new concept, utilizing a toroidal-shaped plasma generator. The beam is extracted from multiple apertures and focus to the target tube, which is located at the middle of the generator. This will generate a point source of D-D, T-T or D-T neutrons with high output flux. The latest development together with measured data will be discussed in this article.

  4. 50 mm Diameter digital DC/pulse neutron generator for subcritical reactor test

    International Nuclear Information System (INIS)

    Li Gang; Zhang Zhongshuai; Chi Qian; Liu Linmao

    2012-01-01

    A 50 mm diameter digital DC/pulse neutron generator was developed with 25 mm ceramic drive-in target neutron tube. It was applied in the subcritical reactor test of China Institute of Atomic Energy (CIAE). The generator can produce neutron in three modes: DC, pulse and multiple pulse. The maximum neutron yield of the generator is 1 × 10 8 n/s, while the maximum pulse frequency is 10 kHz, and the minimum pulse width is 10 μs. As a remote controlled generator, it is small in volume, easy to be connected and controlled. The tested results indicate that penning ion source has the feature of delay time in glow discharge, and it is easier for glow discharge to happen when switching the DC voltage of penning ion source into pulse. According to these two characteristics, the generator has been modified. This improved generator can be used in many other areas including Prompt Gamma Neutron Activation Analysis (PGNAA), neutron testing and experiment.

  5. 50 mm Diameter digital DC/pulse neutron generator for subcritical reactor test

    Energy Technology Data Exchange (ETDEWEB)

    Li Gang; Zhang Zhongshuai [Northeast Normal University, Changchun 130024 (China); Chi Qian [Guang Hua College of Chang Chun University, Changchun 130117 (China); Liu Linmao, E-mail: ll888@nenu.edu.cn [Northeast Normal University, Changchun 130024 (China)

    2012-11-01

    A 50 mm diameter digital DC/pulse neutron generator was developed with 25 mm ceramic drive-in target neutron tube. It was applied in the subcritical reactor test of China Institute of Atomic Energy (CIAE). The generator can produce neutron in three modes: DC, pulse and multiple pulse. The maximum neutron yield of the generator is 1 Multiplication-Sign 10{sup 8} n/s, while the maximum pulse frequency is 10 kHz, and the minimum pulse width is 10 {mu}s. As a remote controlled generator, it is small in volume, easy to be connected and controlled. The tested results indicate that penning ion source has the feature of delay time in glow discharge, and it is easier for glow discharge to happen when switching the DC voltage of penning ion source into pulse. According to these two characteristics, the generator has been modified. This improved generator can be used in many other areas including Prompt Gamma Neutron Activation Analysis (PGNAA), neutron testing and experiment.

  6. Overview of the Division 2351 Neutron Generator Test Facility waveform digitizing system. [Explosively activated neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, T.C. Jr.

    1978-02-01

    All neutron generator waveforms from units tested at the SLA neutron generator test site are digitized and the digitized data stored in the CDC 6600 tape library for display and analysis using the CDC 6600 computer. The digitizing equipment consists mainly of seven Biomation Model 8100 transient recorders, Digital Equipment Corporation PDP 11/20 computer, RK05 disk, seven-track magnetic tape transport, and appropriate DEC and SLA controllers and interfaces. The PDP 11/20 computer is programmed in BASIC with assembly language drivers. In addition to digitizing waveforms, this equipment is used for other functions such as the automated testing of multiple-operation electronic neutron generators. Although other types of analysis have been done, the largest use of the digitized data has been for various types of graphical displays using the CDC 6600 and either the SD4020 or DX4460 plotters.

  7. Criticality experiments: analysis, evaluation, and programs. 8. Prompt Neutron Decay Constants in Uranium Diluted with Matrix Material Systems

    International Nuclear Information System (INIS)

    Sanchez, Rene; Loaiza, David; Brunson, Glenn

    2001-01-01

    Rossi-Alpha measurements were performed on uranium diluted with matrix material systems to determine the prompt neutron decay constants. These constants represent an eigenvalue characteristic of these particular critical assemblies, which can be experimentally measured by the Rossi-Alpha or pulse neutron source techniques and calculated by a deterministic or Monte Carlo method. In the measurements presented in this paper, highly enriched foils diluted in various X/ 235 U ratios with polyethylene and SiO 2 , and polyethylene and aluminum were assembled to a high multiplication, and the prompt neutron decay constants were obtained by the Rossi-Alpha technique. The uranium diluted with matrix material experiments were fueled with highly enriched uranium foils. The average dimensions of the bare foils were 22.86 cm squared and 0.00762 cm thick. The foils were laminated with plastic sheets to reduce the amount of airborne contamination. Each foil weighed ∼70 g. The diluent material consisted of SiO 2 , or 6061 aluminum plates, which were embedded into polyethylene plates. The SiO 2 and aluminum plates were 22.86 cm square and 0.64 cm thick. The polyethylene plates were 39.12 cm square and 1.91 cm thick. Each polyethylene plate had a central recess whose dimensions were 22.86 cm by 22.86 cm by 0.64 cm deep and was used to accommodate the SiO 2 , or aluminum plates as well as the uranium foils. There were eight 39.12-cm-squared by 2.54-cm-thick high density polyethylene plates that form the top and bottom reflectors (four at the top and four at the bottom). Also, one of the polyethylene plates located in the center of the assembly had holes drilled in a radial direction to accommodate neutron detectors. Four 3 He detectors were placed in this plate. The 3 He detectors were 1.27 cm in diameter and ∼15 cm long. Rossi-Alpha measurements were performed at several subcritical separations for both experiments. The data were collected with a type I time analyzer (PATRM

  8. Study of general digital DC/pulse neutron generator

    International Nuclear Information System (INIS)

    Li Gang; Liu Zheng; Li Wensheng; Liu Hanlin; Liu Linmao

    2014-01-01

    Preliminary experimental results of digital DC/pulse neutron generator based on a ceramic drive-in target neutron tube for explosives detection are presented. The generator is a portable and on-off neutron source, and it can be controlled by remote PC. The generator can produce DC neutrons, pulse neutrons and multiple pulse neutrons. The maximum neutron yield is about 2 × 10"8 n/s, the minimum pulse width is 10 μs and the maximum pulse frequency is 10 kHz. Neutron yield and time-spectrum is measured in China Academy of Engineering Physics. The generator is suitable for explosive detection with PFTNA technology, and it can be used in other areas such as reactor measurements and on-line industrial test systems. (authors)

  9. Measurements of fission cross-sections and of neutron production rates; Mesures de sections efficaces de fission et du nombre de neutrons prompts emis par fission

    Energy Technology Data Exchange (ETDEWEB)

    Billaud, P; Clair, C; Gaudin, M; Genin, R; Joly, R; Leroy, J L; Michaudon, A; Ouvry, J; Signarbieux, C; Vendryes, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    a) Measurements of neutron induced fission cross-sections in the low energy region. The variation of the fission cross sections of several fissile isotopes has been measured and analysed, for neutron energies below 0,025 eV. The monochromator was a crystal spectrometer used in conjunction with a mechanical velocity selector removing higher order Bragg reflections. The fissile material was laid down on the plates of a fission chamber by painting technic. An ionization chamber, having its plates coated with thin {sup 10}B layers, was used as the neutron flux monitor. b) Measurement of the fission cross section of {sup 235}U. We intend to measure the variation of the neutron induced fission cross section of {sup 235}U over the neutron energy range from 1 keV by the time of flight method. The neutron source is the uranium target of a pulsed 28 MeV electron linear accelerator. The detector is a large fission chamber, with parallel plates, containing about 10 g of {sup 235}U (20 deposits of 25 cm diameter). The relative fission data were corrected for the neutron spectrum measured with a set of BF{sub 3} proportional counters. c) Mean number {nu} of neutrons emitted in neutron induced fission. We measured the value of {nu} for several fissile isotopes in the case of fission induced by 14 MeV neutrons. The 14 MeV neutrons were produced by D (t, n) {alpha} reaction by means of a 300 kV Cockcroft Walton generator. (author)Fren. [French] a) Mesures de sectionficaces de fission a basse energie. Nous avons mesure et analyse la variation de la section efficace de fission de divers isotopes fissiles pour des neutrons d'energie inferieure a 0,025 eV. Le monochromateur est constitue par un spectrometre a cristal auquel est associe un selecteur mecanique destine a eliminer les diffractions de Bragg d'ordre superieur au premier. Le materiau fissile est contenu dans une chambre a fission sous forme de depots realises par peinture; une chambre d'ionisation a depots minces de B{sub 10

  10. Method and apparatus for generating neutrons

    International Nuclear Information System (INIS)

    Cranberg, L.

    1978-01-01

    An apparatus and method for generating high-energy neutrons are disclosed. Neutron emissive target material is deposited on one or more surfaces on a rotatable, hollow, toroidal target support. The surfaces are bombarded by beams of ions of generally rectangular cross section, so that when the bombarded surfaces are viewed end-wise, a compact, generally square source of neutrons is provided, such as is required for collimation. A combination of molecular and atomic ions emitted from at least one conventional accelerator are passed through a magnetic field for the purpose of separating the ions into one homogeneous group of atomic and one homogeneous group of molecular ions before the ions are allowed to impinge on the target surfaces. One accelerator directs ions to each target surface as the target rotates. Coolant is directed through a cavity within the toroidal support for the purpose of cooling the target support and target material. A refrigerated surface is placed in close proximity to the target surface to condense vapors which might prove harmful to the target and for thermally cooling said target

  11. Neutron generator tube ion source control apparatus

    International Nuclear Information System (INIS)

    Bridges, J.R.

    1982-01-01

    A pulsed neutron well logging system includes a neutron generator tube of the deuterium-tritium accelerator type and an ion source control apparatus providing extremely sharply time-defined neutron pulses. A low voltage control pulse supplied to an input by timing circuits turns a power FET on via a buffer-driver whereby a 2000 volt pulse is produced in the secondary of a pulse transformer and applied to the ion source of the tube. A rapid fall in this ion source control pulse is ensured by a quenching circuit wherein a one-shot responds to the falling edge of the control pulse and produces a 3 microsecond delay to compensate for the propagation delay. A second one-shot is triggered by the falling edge of the output of the first one-shot and gives an 8 microsecond pulse to turn on the power FET which, via an isolation transformer turns on a series-connected transistor to ground the secondary of the pulse transformer and the ion source. (author)

  12. 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.

  13. Application of the Monte Carlo technique to the study of radiation transport in a prompt gamma in vivo neutron activation system

    International Nuclear Information System (INIS)

    Chan, A.A.; Beddoe, A.H.

    1985-01-01

    A Monte Carlo code (MORSE-SGC) from the Radiation Shielding Information Centre at Oak Ridge National Laboratory, USA, has been adapted and used to model radiation transport in the Auckland prompt gamma in vivo neutron activation analysis facility. Preliminary results are presented for the slow neutron flux in an anthropomorphic phantom which are in broad agreement with those obtained by measurement via activation foils. Since experimental optimization is not logistically feasible and since theoretical optimization of neutron activation facilities has not previously been attempted, it is hoped that the Monte Carlo calculations can be used to provide a basis for improved system design

  14. Indoor Fast Neutron Generator for Biophysical and Electronic Applications

    Science.gov (United States)

    Cannuli, A.; Caccamo, M. T.; Marchese, N.; Tomarchio, E. A.; Pace, C.; Magazù, S.

    2018-05-01

    This study focuses the attention on an indoor fast neutron generator for biophysical and electronic applications. More specifically, the findings obtained by several simulations with the MCNP Monte Carlo code, necessary for the realization of a shield for indoor measurements, are presented. Furthermore, an evaluation of the neutron spectrum modification caused by the shielding is reported. Fast neutron generators are a valid and interesting available source of neutrons, increasingly employed in a wide range of research fields, such as science and engineering. The employed portable pulsed neutron source is a MP320 Thermo Scientific neutron generator, able to generate 2.5 MeV neutrons with a neutron yield of 2.0 x 106 n/s, a pulse rate of 250 Hz to 20 KHz and a duty factor varying from 5% to 100%. The neutron generator, based on Deuterium-Deuterium nuclear fusion reactions, is employed in conjunction with a solid-state photon detector, made of n-type high-purity germanium (PINS-GMX by ORTEC) and it is mainly addressed to biophysical and electronic studies. The present study showed a proposal for the realization of a shield necessary for indoor applications for MP320 neutron generator, with a particular analysis of the transport of neutrons simulated with Monte Carlo code and described the two main lines of research in which the source will be used.

  15. Pulsed neutron generator for mass flow measurement using the pulsed neutron activation technique

    International Nuclear Information System (INIS)

    Rochau, G.E.; Hornsby, D.R.; Mareda, J.F.; Riggan, W.C.

    1980-01-01

    A high-output, transportable neutron generator has been developed to measure mass flow velocities in reactor safety tests using the Pulsed Neutron Activation (PNA) Technique. The PNA generator produces >10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. The Millisecond Pulse (MSP) Neutron Tube, developed for this application, has an expected operational life of 1000 pulses, and it limits the generator pulse repetition rate to 12 pulses/minute. A semiconductor neutron detector is included in the generator package to monitor the neutron output. The control unit, which can be operated manually or remotely, also contains a digital display with a BCD output for the neutron monitor information. The digital logic of the unit controls the safety interlocks and rejects transient signals which could accidently fire the generator

  16. Nitrogen Detection in Bulk Samples Using a D-D Reaction-Based Portable Neutron Generator

    Directory of Open Access Journals (Sweden)

    A. A. Naqvi

    2013-01-01

    Full Text Available Nitrogen concentration was measured via 2.52 MeV nitrogen gamma ray from melamine, caffeine, urea, and disperse orange bulk samples using a newly designed D-D portable neutron generator-based prompt gamma ray setup. Inspite of low flux of thermal neutrons produced by D-D reaction-based portable neutron generator and interference of 2.52 MeV gamma rays from nitrogen in bulk samples with 2.50 MeV gamma ray from bismuth in BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays indicates satisfactory performance of the setup for detection of nitrogen in bulk samples.

  17. Yield of Prompt Gamma Radiation in Slow-Neutron Induced Fission of 235U as a Function of the Total Fragment Kinetic Energy

    Energy Technology Data Exchange (ETDEWEB)

    Albinsson, H [Chalmers Univ. of Technology, Goeteborg (SE)

    1971-07-01

    Fission gamma radiation yields as functions of the total fragment kinetic energy were obtained for 235U thermal-neutron induced fission. The fragments were detected with silicon surface-barrier detectors and the gamma radiation with a Nal(Tl) scintillator. In some of the measurements mass selection was used so that the gamma radiation could also be measured as a function of fragment mass. Time discrimination between the fission gammas and the prompt neutrons released in the fission process was employed to reduce the background. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fission fragments. Fission-neutron and gamma-ray data of previous experiments were used for comparisons of the yields, and estimates were made of the variation of the prompt gamma-ray energy with the total fragment kinetic energy

  18. Prompt fission neutron spectra from fission induced by 1 to 8 MeV neutrons on 235U and 239Pu using the double time-of-flight technique

    International Nuclear Information System (INIS)

    Noda, S.; Haight, R. C.; Nelson, R. O.; Devlin, M.; O'Donnell, J. M.; Chatillon, A.; Granier, T.; Belier, G.; Taieb, J.; Kawano, T.; Talou, P.

    2011-01-01

    Prompt fission neutron spectra from 235 U and 239 Pu were measured for incident neutron energies from 1 to 200 MeV at the Weapons Neutron Research facility (WNR) of the Los Alamos Neutron Science Center, and the experimental data were analyzed with the Los Alamos model for the incident neutron energies of 1-8 MeV. A CEA multiple-foil fission chamber containing deposits of 100 mg 235 U and 90 mg 239 Pu detected fission events. Outgoing neutrons were detected by the Fast Neutron-Induced γ-Ray Observer array of 20 liquid organic scintillators. A double time-of-flight technique was used to deduce the neutron incident energies from the spallation target and the outgoing energies from the fission chamber. These data were used for testing the Los Alamos model, and the total kinetic energy parameters were optimized to obtain a best fit to the data. The prompt fission neutron spectra were also compared with the Evaluated Nuclear Data File (ENDF/B-VII.0). We calculate average energies from both experimental and calculated fission neutron spectra.

  19. Development of compact D-D neutron generator

    International Nuclear Information System (INIS)

    Das, Basanta Kumar; Das, Rashmita; Shyam, Anurag

    2011-12-01

    In recent years, due to specific features of compact neutron generators, their demand in elemental analysis and detection of the illicit materials has been increased in scientific community. Compact is size, controlled operation and radiation safety like features of neutron generator is suitable for research work with illicit materials. An accelerator based neutron generator can be operated in steady mode as well as in pulse mode. The main embodiment of this type of generator includes ion source, ion acceleration system and target. We are developing such type of neutron generator. This consists of one-in-house developed penning ion source, a single electrode acceleration gap and one deuterated titanium target or virgin titanium target. In this report, we will discuss various physics and technical issues related to the important components of this generator, operation of the generator and neutron detection. (author)

  20. Generation of laser-induced fast neutron and its application

    International Nuclear Information System (INIS)

    Cha, Hyung Ki; Lee, S.; Kwon, D.; Nam, S.; Park, S.; Rhee, Y.; Jung, Y.; Lee, K.; Cha, Y.; Kwon, S.; Lim, C.; Han, J.; Park, S.; Chung, C.

    2012-04-01

    The supply of high-efficiency neutron source is still problematic even though a fast neutron source is being accepted increasingly for industrial applications. Radioisotopes and a neutron tube are typically being used, but their neutron flux, lifetime, and price are the limiting factors for more diverse applications. As ultra high power, short pulse laser technologies have been developed, a neutron source generated via laser induced nuclear reaction comes to the fore. The laser induced neutron source has a high peak flux in comparison to the traditional neutron source and is like a point source with its diameter less than 1 mm. These properties can be utilized effectively for the analysis of pulsed fast neutron activation or the studies of a fast neutron material damage and/or recover. The purpose of R and D here is to develop a robust neutron source with a yield of 107 neutrons/s during 1st R and D stage ('07 ∼ '09) and to construct a stable laser neutron source in longer operation and to demonstrate its usefulness for a neutron activation analysis of explosive materials and a neutron impact analysis of crystalline in the second R and D stage ('10 ∼ '11)

  1. Fusion neutron detector calibration using a table-top laser generated plasma neutron source

    International Nuclear Information System (INIS)

    Hartke, R.; Symes, D.R.; Buersgens, F.; Ruggles, L.E.; Porter, J.L.; Ditmire, T.

    2005-01-01

    Using a high intensity, femtosecond laser driven neutron source, a high-sensitivity neutron detector was calibrated. This detector is designed for observing fusion neutrons at the Z accelerator in Sandia National Laboratories. Nuclear fusion from laser driven deuterium cluster explosions was used to generate a clean source of nearly monoenergetic 2.45 MeV neutrons at a well-defined time. This source can run at 10 Hz and was used to build up a clean pulse-height spectrum on scintillating neutron detectors giving a very accurate calibration for neutron yields at 2.45 MeV

  2. Monitoring of blood-10B concentration for boron neutron capture therapy using prompt gamma-ray analysis

    International Nuclear Information System (INIS)

    Raaijmakers, C.P.J.; Konijnenberg, M.W.; Dewit, L.; Mijnheer, B.J.; Haritz, D.; Huiskamp, R.; Philipp, K.; Siefert, A.; Stecher-Rasmussen, F.

    1995-01-01

    The aim of the present study was to monitor the blood- 10 B concentration of laboratory dogs receiving boron neutron capture therapy, in order to obtain optimal agreement between prescribed and actual dose. A prompt gamma-ray analysis system was developed for this purpose at the High Flux Reactor in Petten. The technique was compared with inductively coupled plasma-atomic emission spectrometry and showed good agreement. A substantial variation in 10 B clearance pattern after administration of borocaptate sodium was found between the different dogs. Consequently, the irradiation commencement was adjusted to the individually determined boron elimination curve. Mean blood- 10 B concentratios during irradiation of 25.8±2.2 μg/g (1 SD, n=18) and 49.3±5.3 μg/g (1 SD, n=17) were obtained for intended concentrations of 25 μg/g and 50 μg/g, respectively. These variations are a factor of two smaller than irradiations performed at a uniform post-infusion irradiation starting time. Such a careful bolld- 10 B monitoring procedure is a prerequisite for accurately obtaining such steep dose-response curves as observed during the dog study. (orig.)

  3. Pulsed thermal neutron source at the fast neutron generator.

    Science.gov (United States)

    Tracz, Grzegorz; Drozdowicz, Krzysztof; Gabańska, Barbara; Krynicka, Ewa

    2009-06-01

    A small pulsed thermal neutron source has been designed based on results of the MCNP simulations of the thermalization of 14 MeV neutrons in a cluster-moderator which consists of small moderating cells decoupled by an absorber. Optimum dimensions of the single cell and of the whole cluster have been selected, considering the thermal neutron intensity and the short decay time of the thermal neutron flux. The source has been built and the test experiments have been performed. To ensure the response is not due to the choice of target for the experiments, calculations have been done to demonstrate the response is valid regardless of the thermalization properties of the target.

  4. Neutron multiplication in lead in the experiments with neutron generators

    International Nuclear Information System (INIS)

    Markovskij, D.V.

    1989-01-01

    A calculational analysis of neutron multiplication in lead, including the estimates of multiplication limits for the standard ENDF/BIV data set and the effects of various changes in the data themselves is performed. 10 refs, 5 figs

  5. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Science.gov (United States)

    Čufar, Aljaž; Batistoni, Paola; Conroy, Sean; Ghani, Zamir; Lengar, Igor; Milocco, Alberto; Packer, Lee; Pillon, Mario; Popovichev, Sergey; Snoj, Luka; JET Contributors

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium-tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle-energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  6. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Čufar, Aljaž, E-mail: aljaz.cufar@ijs.si [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Conroy, Sean [Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Ghani, Zamir [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Lengar, Igor [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Milocco, Alberto; Packer, Lee [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Pillon, Mario [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Snoj, Luka [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium–tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle–energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  7. Development of a sealed-accelerator-tube neutron generator

    Science.gov (United States)

    Verbeke; Leung; Vujic

    2000-10-01

    Sealed-accelerator-tube neutron generators are being developed in Lawrence Berkeley National Laboratory (LBNL) for applications ranging from neutron radiography to boron neutron capture therapy and neutron activation analysis. The new generation of high-output neutron generators is based on the D-T fusion reaction, producing 14.1-MeV neutrons. The main components of the neutron tube--the ion source, the accelerator and the target--are all housed in a sealed metal container without external pumping. Thick-target neutron yield computations are performed in this paper to estimate the neutron yield of titanium and scandium targets. With an average deuteron beam current of 1 A and an energy of 120 keV, a time-averaged neutron production of approximately 10(14) n/s can be estimated for a tritiated target, for both pulsed and cw operations. In mixed deuteron/triton beam operation, a beam current of 2 A at 150 keV is required for the same neutron output. Recent experimental results on ion sources and accelerator columns are presented and discussed.

  8. Analysis of the neutron generation from a D-Li neutron source

    International Nuclear Information System (INIS)

    Gomes, I.

    1994-02-01

    The study of the neutron generation from the D-Li reaction is an important issue to define the optimum combination of the intervening parameters during the design phase of a D-Li neutron source irradiation facility. The major players in defining the neutron yield from the D-Li reaction are the deuteron incident energy and the beam current, provided that the lithium target is thick enough to stop all incident deuterons. The incident deuteron energy also plays a role on the angular distribution of the generated neutrons, on the energy distribution of the generated neutrons, and on the maximum possible energy of the neutrons. The D-Li reaction produces neutrons with energies ranging from eV's to several MeV's. The angular distribution of these neutrons is dependent on the energy of both, incident deuterons and generated neutrons. The deuterons lose energy interacting with the lithium target material in such a way that the energy of the deuterons inside the lithium target varies from the incident deuteron energy to essentially zero. The first part of this study focuses in analyzing the neutron generation rate from the D-Li reaction as a function of the intervening parameters, in defining the source term, in terms of the energy and angular distributions of the generated neutrons, and finally in providing some insights of the impact of varying input parameters on the generation rate and correlated distributions. In the second part an analytical description of the Monte Carlo sampling procedure of the neutron from the D-Li reaction is provided with the aim at further Monte Carlo transport of the D-Li neutrons

  9. Design and Fabrication of Titanium Target for Portable Neutron Generator

    International Nuclear Information System (INIS)

    Lee, Cheol Ho; Oh, Byunghoon; Chang, Daesik; Jang, Dohyun; In Sang Yeol; Park, Jaewon; Hong, Kwangpyo

    2014-01-01

    For the neutron generator to produce a neutron flux of the above order, a target that produces fast neutrons in the generator plays an important role, and the target is used and applied to develop the generator due to its simplicity and inexpensive. Making suitable targets for neutron production, especially mono-energy neutrons, has always been of interest. These targets have been used for neutron production reaction studies, calibration of detectors, and neutron therapy. Different studies have been carried out on deuterium and tritium for making solid targets to produce mono-energy neutron from D-D and D-T reactions. A lot of investigations have been carried out on solid target properties such as lifetime, thermal stability, neutron yield, and energy. Vaporized zirconium and titanium layers on a high thermal conductivity substrate (Cu, Mo, Ag) have been used as deuterium and tritium absorbing metals. The density of titanium is smaller than zirconium and the range of charged particles in the titanium targets is more than that in zirconium targets. Thus, titanium targets have more neutron yield than zirconium targets in a low energy beam and titanium is usually used to make a target. The titanium target was designed and simulated to determine the suitable thickness of the target. As a result of the simulation, the target was fabricated to generate fast neutrons by the reaction. The thickness of the target was measured using a profiler. The thickness of the two targets is 2.108 and 2.190 μm. The target will be applied to produce neutrons in a neutron generator

  10. The intensive DT neutron generator of TU Dresden

    Science.gov (United States)

    Klix, Axel; DÖring, Toralf; Domula, Alexander; Zuber, Kai

    2018-01-01

    TU Dresden operates an accelerator-based intensive DT neutron generator. Experimental activities comprise investigation into material activation and decay, neutron and photon transport in matter and R&D work on radiation detectors for harsh environments. The intense DT neutron generator is capable to produce a maximum of 1012 n/s. The neutron source is a solid-type water-cooled tritium target based on a titanium matrix on a copper carrier. The neutron yield at a typical deuteron beam current of 1 mA is of the order of 1011 n/s in 4Π. A pneumatic sample transport system is available for short-time irradiations and connected to wo high-purity germanium detector spectrometers for the measurement of induced activities. The overall design of the experimental hall with the neutron generator allows a flexible setup of experiments including the possibility of investigating larger structures and cooled samples or samples at high temperatures.

  11. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel—Design concept and experimental demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Henzlova, D., E-mail: henzlova@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Menlove, H.O.; Rael, C.D.; Trellue, H.R.; Tobin, S.J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong [Korea Atomic Energy Research Institute, Daejeong (Korea, Republic of)

    2016-01-11

    This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

  12. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel—Design concept and experimental demonstration

    International Nuclear Information System (INIS)

    Henzlova, D.; Menlove, H.O.; Rael, C.D.; Trellue, H.R.; Tobin, S.J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

    2016-01-01

    This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

  13. Evaluation of the {sup 239}Pu prompt fission neutron spectrum induced by neutrons of 500 keV and associated covariances

    Energy Technology Data Exchange (ETDEWEB)

    Neudecker, D., E-mail: dneudecker@lanl.gov [Theoretical Division, Los Alamos National Laboratory, P.O. Box 1663, MS-B283, NM 87545 (United States); Talou, P., E-mail: talou@lanl.gov [Theoretical Division, Los Alamos National Laboratory, P.O. Box 1663, MS-B283, NM 87545 (United States); Kawano, T., E-mail: kawano@lanl.gov [Theoretical Division, Los Alamos National Laboratory, P.O. Box 1663, MS-B283, NM 87545 (United States); Smith, D.L., E-mail: donaldlarnedsmith@gmail.com [Nuclear Engineering Division, Argonne National Laboratory, 1710 Avenida del Mundo #1506, Coronado, CA 92118 (United States); Capote, R., E-mail: r.capotenoy@iaea.org [Nuclear Data Section, International Atomic Energy Agency Vienna, Vienna International Centre, P.O. Box 100, A-1400 Vienna (Austria); Rising, M.E., E-mail: mrising@lanl.gov [X-Division, Los Alamos National Laboratory, P.O. Box 1663, MS-F663, NM 87545 (United States); Kahler, A.C., E-mail: akahler@lanl.gov [Theoretical Division, Los Alamos National Laboratory, P.O. Box 1663, MS-B283, NM 87545 (United States)

    2015-08-11

    We present evaluations of the prompt fission neutron spectrum (PFNS) of {sup 239}Pu induced by 500 keV neutrons, and associated covariances. In a previous evaluation by Talou et al. (2010), surprisingly low evaluated uncertainties were obtained, partly due to simplifying assumptions in the quantification of uncertainties from experiment and model. Therefore, special emphasis is placed here on a thorough uncertainty quantification of experimental data and of the Los Alamos model predicted values entering the evaluation. In addition, the Los Alamos model was extended and an evaluation technique was employed that takes into account the qualitative differences between normalized model predicted values and experimental shape data. These improvements lead to changes in the evaluated PFNS and overall larger evaluated uncertainties than in the previous work. However, these evaluated uncertainties are still smaller than those obtained in a statistical analysis using experimental information only, due to strong model correlations. Hence, suggestions to estimate model defect uncertainties are presented, which lead to more reasonable evaluated uncertainties. The calculated k{sub eff} of selected criticality benchmarks obtained with these new evaluations agree with each other within their uncertainties despite the different approaches to estimate model defect uncertainties. The k{sub eff} one standard deviations overlap with some of those obtained using ENDF/B-VII.1, albeit their mean values are further away from unity. Spectral indexes for the Jezebel critical assembly calculated with the newly evaluated PFNS agree with the experimental data for selected (n,γ) and (n,f) reactions, and show improvements for high-energy threshold (n,2n) reactions compared to ENDF/B-VII.1.

  14. Utilization of low voltage D-T neutron generators in neutron physics studies

    Energy Technology Data Exchange (ETDEWEB)

    Singkarat, S.

    1995-08-01

    In a small nuclear laboratory of a developing country a low voltage D-T neutron generator can be a very useful scientific apparatus. Such machines have been used successfully for more than 40 years in teaching and scientific research. The original continuous mode 150-kV D-T neutron generator has been modified to have also a capability of producing 2-ns pulsed neutrons. Together with a carefully designed 10 m long flight path collimator and shielding of a 25 cm diameter {center_dot} 10 cm thick BC-501 neutron detector, the pulsing system was successfully used for measuring the double differential cross-section (DDX) of natural iron for 14.1-MeV neutron from the angle of 30 deg to 150 deg in 10 deg steps. In order to extend the utility of the generator, two methods for converting the almost monoenergetic 14-MeV neutrons to monoenergetic neutrons of lower energy were proposed and tested. The first method uses a pulsed neutron generator and the second method uses an ordinary continuous mode generator. The latter method was successfully used to measure the scintillation light output of a 1.4 cm diameter spherical NE-213 scintillation detector. The neutron generator has also been used in the continuous search for improved neutron detection techniques. There is a proposal, based on Monte Carlo calculations, of using a scintillation fiber for a fast neutron spectrometer. Due to the slender shape of the fiber, the pattern of produced light gives a peak in the pulse height spectrum instead of the well-known rectangular-like distribution, when the fiber is bombarded end-on by a beam of 14-MeV neutrons. Experimental investigations were undertaken. Detailed investigations on the light transportation property of a short fiber were performed. The predicted peak has not yet been found but the fiber detector may be developed as a directional discrimination fast neutron detector. 18 refs.

  15. The Design of a Prompt Gamma Neutron Activation Analysis Beam for BNCT Purpose at the TRIGA Mark II Reactor in Pavia

    Energy Technology Data Exchange (ETDEWEB)

    Stella, S.; Bazani, A.; Ballarini, F.; Bortolussi, S.; Protti, N.; Altieri, S. [Department of Nuclear and Theoretical Physics, University of Pavia (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Section of Pavia (Italy); Bruschi, P. [Department of Nuclear and Theoretical Physics, University of Pavia (Italy)

    2011-07-01

    In preclinical and clinical Boron Neutron Capture Therapy studies the knowledge of the amount of {sup 10}B in blood and tissues is very important. The boron concentration measurements method used in Pavia (Italy) is based on the charged particles spectrometry of thin tissue cuts irradiated in the Thermal Column of the TRIGA reactor of the University. In order to perform measurements in biological liquids such as blood and urine, or in other tissue that cannot be cut in slices, a Prompt Gamma Neutron Activation Analysis (PGNAA) facility is being designed, which measures {sup 10}B concentration detecting the prompt gamma from boron nuclear capture reaction. At the TRIGA reactor in Pavia, there are four horizontal channels, potentially available for PGNAA. The choice of the suitable channel, and the design of its configuration, were achieved using the Monte Carlo neutron transport code MCNP4c2. To perform the simulations, an input code already validated, describing the reactor structure and the neutron source, was used. The calculations were implemented applying non-analog techniques for the neutron transport, that are necessary to obtain a sufficient statistic in every positions along the channel and especially at its end. The selection of the channel for PGNAA installation was carried out by comparing the simulated fluxes obtained in the different channels at the present configuration. The channel shielded by the core reflector was chosen, because the graphite lowers the fast component of the neutrons, with no need to insert additional material in the facility. The thermal flux at its end is 1.7 x 10{sup 8} n/cm{sup 2} s with thermal-to-total neutron flux ratio around 0.8. Subsequently a bismuth block for gamma radiation shielding and blocks of single crystal sapphire as filter for fast neutron component were inserted in the channel. Other components of the facility that are under study are a collimator and the beam catcher. (author)

  16. Mechanism of neutron generation in Z-pinches

    International Nuclear Information System (INIS)

    Vikhrev, V.V.

    1986-01-01

    The review of experimental and theoretical investigations in a mechanism of neutron generation in Z-pinches is presented. Special attention is paid to the thermonuclear mechanism of neutron generation occuring due to the formation of high-temperature plasma regions in Z-pinch sausage-type instabilities. This mechanism is shown to be predominant in charges with the neutron yield more than 10 9 per a charge. Experimental data, which are considered to be contradicting to thermonuclear nature of neutron radiation, are explained

  17. Development of an experimental device based on the digitalization of the signal and dedicated to the characterization of fission fragments and prompt neutrons

    International Nuclear Information System (INIS)

    Varapai, N.

    2006-12-01

    The present work demonstrates the application of the digital technique for nuclear measurements. This new technique is based on the digitalization of the signals from the detectors and has several advantages. This technique allows us to extract the maximum amount of information contained in the signal shape. In the case of an ionization chamber this signal contains the necessary information on the particle kinetic energy, emission angle and mass. This method has been implemented for measurements of promptly emitted fission neutrons in coincidence with fission fragments from 252 Cf(sf). A double Frisch-grid ionization chamber is used as fission fragment detector. The promptly emitted neutrons are detected by a NE213 liquid scintillation detector. This work displays how delicate analysis of the digitalized signals permitted us to infer the mass and kinetic energy distributions of the fission fragments as well as the neutron energy spectrum and multiplicity. The outline of this thesis is as follows: Chapter 2 gives an overview of the experimental tools used in this work. Chapter 3 explains the analysis procedure of the digitalized anode signal from an ionization chamber. Chapter 4 gives a detailed explanation of the analysis procedure of the digitalized signal from a neutron detector. In Chapter 5 the analysis procedure of the fission fragment events in coincidence with neutrons is given

  18. Measurement of (n,xn) reaction cross-sections using prompt {gamma} spectroscopy at neutron beams with high instantaneous flux; Mesure de sections efficaces de reaction (n,xn) par spectroscopie {gamma} prompte aupres d'un faisceau a tres haut flux instantane

    Energy Technology Data Exchange (ETDEWEB)

    Lukic, S

    2004-10-15

    The work presented in this thesis is situated in the context of the GEDEON program of neutron cross-section measurements. This program is motivated by the perspectives recently opened by projects of nuclear waste treatment and energy production. There is an obvious lack of experimental data on (n,xn) reactions in the databases, especially in the case of very radioactive isotopes. An important technique to measure cross-sections of these reactions is the prompt {gamma}-ray spectroscopy at white pulsed neutron beams with very high instantaneous flux. In this work, inelastic scattering and (n,xn) reactions cross-section measurements were performed on a lead sample from threshold to 20 MeV by prompt {gamma}-ray spectroscopy at the white neutron beam generated by GELINA facility in Geel, Belgium. Digital methods were developed to treat HPGe CLOVER detector signals and separate {gamma}-rays induced by the fastest neutrons from those belonging to the flash. Partial cross-sections for the production of several transitions in natural lead were measured and analyzed using theoretical calculations in order to separate the contributions of different reactions leading to the same residual isotope. Total cross-sections of the reactions in question were estimated. The results were compared to the TALYSS code theoretical calculations, as well as to other experimental results. This experiment has served to validate the method and it opens the way to measure (n,xn) reactions cross-sections with high instantaneous neutron flux on actinides, particularly the U{sup 233}(n,2n) reaction which is important for the thorium cycle. (author)

  19. Radiological safety aspects of the operation of neutron generators

    International Nuclear Information System (INIS)

    Boggs, R.F.

    1976-01-01

    The purpose of the manual is to provide some basic guidelines to persons with a minimum of training in radiological health or health physics, on some safety aspects of the operation of sealed-tube and Cockcroft-Walton type neutron generators. The manual does not state rules or regulations but presents a description of the most likely hazards. It is relevant to those relatively compact neutron generators which usually operate at less than 150-200 kV for the purpose of producing 14-MeV neutrons. The scope is limited to basic discussions of hazards and measurement techniques. Separate chapters are devoted to the characteristics and use of neutron generators; radiation hazards and safety considerations; radiation monitoring and interpretation of measurements; and requirements for an effective safety programme. Two appendices deal with non-radiation hazards and safety considerations, and with a neutron generator laboratory, respectively. An extensive list of bibliographic references is included

  20. Performance test results of noninvasive characterization of Resource Conservation and Recovery Act surrogate waste by prompt gamma neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, R.J.; Streier, G.G.

    1997-03-01

    During FY-96, a performance test was carried out with funding from the Mixed Waste Focus Area (MWFA) of the Department of Energy (DOE) to determine the noninvasive elemental assay capabilities of commercial companies for Resource Conservation and Recovery Act (RCRA) metals present in 8-gal drums containing surrogate waste. Commercial companies were required to be experienced in the use of prompt gamma neutron activation analysis (PGNAA) techniques and to have a prototype assay system with which to conduct the test assays. Potential participants were identified through responses to a call for proposals advertised in the Commerce Business Daily and through personal contacts. Six companies were originally identified. Two of these six were willing and able to participate in the performance test, as described in the test plan, with some subsidizing from the DOE MWFA. The tests were conducted with surrogate sludge waste because (1) a large volume of this type of waste awaits final disposition and (2) sludge tends to be somewhat homogeneous. The surrogate concentrations of the above RCRA metals ranged from {approximately} 300 ppm to {approximately} 20,000 ppm. The lower limit was chosen as an estimate of the expected sensitivity of detection required by noninvasive, pretreatment elemental assay systems to be of value for operational and compliance purposes and to still be achievable with state-of-the-art methods of analysis. The upper limit of {approximately} 20,000 ppm was chosen because it is the opinion of the author that assay above this concentration level is within current state-of-the-art methods for most RCRA constituents. This report is organized into three parts: Part 1, Test Plan to Evaluate the Technical Status of Noninvasive Elemental Assay Techniques for Hazardous Waste; Part 2, Participants` Results; and Part 3, Evaluation of and Comments on Participants` Results.

  1. Performance test results of noninvasive characterization of Resource Conservation and Recovery Act surrogate waste by prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Gehrke, R.J.; Streier, G.G.

    1997-03-01

    During FY-96, a performance test was carried out with funding from the Mixed Waste Focus Area (MWFA) of the Department of Energy (DOE) to determine the noninvasive elemental assay capabilities of commercial companies for Resource Conservation and Recovery Act (RCRA) metals present in 8-gal drums containing surrogate waste. Commercial companies were required to be experienced in the use of prompt gamma neutron activation analysis (PGNAA) techniques and to have a prototype assay system with which to conduct the test assays. Potential participants were identified through responses to a call for proposals advertised in the Commerce Business Daily and through personal contacts. Six companies were originally identified. Two of these six were willing and able to participate in the performance test, as described in the test plan, with some subsidizing from the DOE MWFA. The tests were conducted with surrogate sludge waste because (1) a large volume of this type of waste awaits final disposition and (2) sludge tends to be somewhat homogeneous. The surrogate concentrations of the above RCRA metals ranged from ∼ 300 ppm to ∼ 20,000 ppm. The lower limit was chosen as an estimate of the expected sensitivity of detection required by noninvasive, pretreatment elemental assay systems to be of value for operational and compliance purposes and to still be achievable with state-of-the-art methods of analysis. The upper limit of ∼ 20,000 ppm was chosen because it is the opinion of the author that assay above this concentration level is within current state-of-the-art methods for most RCRA constituents. This report is organized into three parts: Part 1, Test Plan to Evaluate the Technical Status of Noninvasive Elemental Assay Techniques for Hazardous Waste; Part 2, Participants' Results; and Part 3, Evaluation of and Comments on Participants' Results

  2. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    Langford, O.M.; Peelman, H.E.

    1980-01-01

    A gas filled neutron tube in a nuclear well logging tool has a target an ion source voltage and a replenisher connected to ground. A negative high voltage is applied to the target by a power supply also providing a target current corresponding to the neutron output of the neutron generator tube. A constant current source provides a constant current. A network receiving the target current and the constant current provides a portion of the constant current as a replenisher current which is applied to the replenisher in a neutron generating tube. The network controls the magnitude of the replenisher current in accordance with the target current so as to control the neutron output of the neutron generating tube. (auth)

  3. Production of radionuclides by 14 MeV neutron generator

    International Nuclear Information System (INIS)

    Alfassi, Z.B.

    1983-01-01

    Due to the short half-lives of these nuclides they have to be produced in situ or at least not far from the place of use. The cost of 14 MeV neutron generators have been compared with the typical middle-sized cyclotrons and it was found that the capital costs are much lower in the case of neutron generators. This is the main reason for the availability of 14 MeV neutron generators in many scientific institutes compared to the scarcity of cyclotrons. Lately, the use of 14 MeV neutrons for cancer therapy was studied in several medical centers. A number of hospitals and cancer research centers have high intensity 14 MeV neutron generators for this purpose. The advantages of using short-lived in-house produced radionuclides suggest the use of the available 14 MeV neutron generators for biological studies and in medical diagnosis. 14 MeV neutron generators can be used to produce some of the medically useful radionuclides, such as /sup 18/F, /sup 80/Br, /sup 199m/Hg, and others. However, the amount required for medicine can only be prepared by the new high intensity neutron generators, used for neutron therapy and not by the smaller ones, commonly used in university laboratories (--10/sup 11/ n/sec). On the other hand, these relatively small neutron generators can be used for the preparation of radionuclides for biological studies. They facilitate the study of metabolism of elements for which radionuclides cannot be usually purchased due to short half-lives or the high price of the long-lived ones, such as /sup 34m/Cl, /sup 18/F, /sup 28,29/Al, /sup 27/Mg, and others. An example is the work done on the fate of Al and Mg in rats using /sup 28/Al and /sup 27/Mg./sup 13/

  4. Fission multipliers for D-D/D-T neutron generators

    International Nuclear Information System (INIS)

    Lou, T.P.; Vujic, J.L.; Koivunoro, H.; Reijonen, J.; Leung, K.-N.

    2003-01-01

    A compact D-D/D-T fusion based neutron generator is being designed at the Lawrence Berkeley National Laboratory to have a potential yield of 10 12 D-D n/s and 10 14 D-T n/s. Because of its high neutron yield and compact size (∼20 cm in diameter by 4 cm long), this neutron generator design will be suitable for many applications. However, some applications required higher flux available from nuclear reactors and spallation neutron sources operated with GeV proton beams. In this study, a subcritical fission multiplier with k eff of 0.98 is coupled with the compact neutron generators in order to increase the neutron flux output. We have chosen two applications to show the gain in flux due to the use of fission multipliers--in-core irradiation and out-of-core irradiation. For the in-core irradiation, we have shown that a gain of ∼25 can be achieved in a positron production system using D-T generator. For the out-of-core irradiation, a gain of ∼17 times is obtained in Boron Neutron Capture Therapy (BNCT) using a D-D neutron generator. The total number of fission neutrons generated by a source neutron in a fission multiplier with k eff is ∼50. For the out-of-core irradiation, the theoretical maximum net multiplication is ∼30 due to the absorption of neutrons in the fuel. A discussion of the achievable multiplication and the theoretical multiplication will be presented in this paper

  5. Generation of laser-induced fast neutron and its application

    International Nuclear Information System (INIS)

    Cha, Hyung Ki; Kwon, D. H.; Nam, S. M.

    2010-04-01

    The supply of high-efficiency neutron source is still problematic even though a fast neutron source is being accepted increasingly for industrial applications. Radioisotopes and a neutron tube are typically being used, but their neutron flux, lifetime, and price are the limiting factors for more diverse applications. As ultra high power, short pulse laser technologies have been developed, a neutron source generated via laser induced nuclear reaction comes to the fore. The laser induced neutron source has a high peak flux in comparison to the traditional neutron source and is like a point source with its diameter less than 1 mm. These properties can be utilized effectively for the analysis of pulsed fast neutron activation or the studies of a fast neutron material damage and/or recover. The purpose of R and D here is to develop a robust neutron source with a yield of 10 7 neutrons/s, and to carry out a preliminary research for application study in the next research stage

  6. Research and development activities of a neutron generator facility

    International Nuclear Information System (INIS)

    Darsono Sudjatmoko; Pramudita Anggraita; Sukarman Aminjoyo

    2000-01-01

    The neutron generator facility at YNRC is used for elemental analysis, nuclear data measurement and education. In nuclear data measurement the focus is on re-evaluating the existing scattered nuclear activation cross-section to obtain systematic data for nuclear reactions such as (n,p), (n,α), and (n,2n). In elemental analysis it is used for analyzing the Nitrogen (N), Phosphor (P) and Potassium (K) contents in chemical and natural fertilizers (compost), protein in rice, soybean, and corn and pollution level in rivers. The neutron generator is also used for education and training of BATAN staff and university students. The facility can also produce neutron generator components. (author)

  7. Generating energy dependent neutron flux maps for effective ...

    African Journals Online (AJOL)

    For activation analysis and irradiation scheme of miniature neutron source reactor, designers or engineers usually require information on thermal neutron flux levels and other energy group flux levels (such as fast, resonance and epithermal). A methodology for readily generating such flux maps and flux profiles for any ...

  8. Research possibilities with an intense neutron generator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.

    1966-01-01

    As the title suggests this paper will depart somewhat from the general topic of this session and will be concerned more with applications of accelerators than with accelerators them elves. The particular application of interest at our laboratory concerns the use of a high current intermediate energy proton accelerator as the basis for a versatile intense neutron source. Chalk River's entry into the intermediate energy accelerator field with neutron production as the primary motivation is somewhat unusual. Although neutron production is also being explored by other laboratories interested in intermediate energy accelerators, e.g., Oak Ridge National Laboratory and Los Alamos Scientific Laboratory, it has not been the major motivation. Our initial motivation was in fact the production of thermal neutrons and this interest has remained foremost in our ING program. We are currently writing a proposal for this project. Our target is to have a proton beam in 1973. (author)

  9. Research possibilities with an intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G A

    1966-07-01

    As the title suggests this paper will depart somewhat from the general topic of this session and will be concerned more with applications of accelerators than with accelerators them elves. The particular application of interest at our laboratory concerns the use of a high current intermediate energy proton accelerator as the basis for a versatile intense neutron source. Chalk River's entry into the intermediate energy accelerator field with neutron production as the primary motivation is somewhat unusual. Although neutron production is also being explored by other laboratories interested in intermediate energy accelerators, e.g., Oak Ridge National Laboratory and Los Alamos Scientific Laboratory, it has not been the major motivation. Our initial motivation was in fact the production of thermal neutrons and this interest has remained foremost in our ING program. We are currently writing a proposal for this project. Our target is to have a proton beam in 1973. (author)

  10. Note: Coincidence measurements of 3He and neutrons from a compact D-D neutron generator

    Science.gov (United States)

    Ji, Q.; Lin, C.-J.; Tindall, C.; Garcia-Sciveres, M.; Schenkel, T.; Ludewigt, B. A.

    2017-05-01

    Tagging of neutrons (2.45 MeV) with their associated 3He particles from deuterium-deuterium (D-D) fusion reactions has been demonstrated in a compact neutron generator setup enabled by a high brightness, microwave-driven ion source with a high fraction of deuterons. Energy spectra with well separated peaks of the D-D fusion reaction products, 3He, tritons, and protons, were measured with a silicon PIN diode. The neutrons were detected using a liquid scintillator detector with pulse shape discrimination. By correlating the 3He detection events with the neutron detection in time, we demonstrated the tagging of emitted neutrons with 3He particles detected with a Si PIN diode detector mounted inside the neutron generator vacuum vessel.

  11. Development of a technique using MCNPX code for determination of nitrogen content of explosive materials using prompt gamma neutron activation analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Nasrabadi, M.N., E-mail: mnnasrabadi@ast.ui.ac.ir [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Bakhshi, F.; Jalali, M.; Mohammadi, A. [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2011-12-11

    Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma 10.8 MeV following radioactive neutron capture by {sup 14}N nuclei. We aimed to study the feasibility of using field-portable prompt gamma neutron activation analysis (PGNAA) along with improved nuclear equipment to detect and identify explosives, illicit substances or landmines. A {sup 252}Cf radio-isotopic source was embedded in a cylinder made of high-density polyethylene (HDPE) and the cylinder was then placed in another cylindrical container filled with water. Measurements were performed on high nitrogen content compounds such as melamine (C{sub 3}H{sub 6}N{sub 6}). Melamine powder in a HDPE bottle was placed underneath the vessel containing water and the neutron source. Gamma rays were detected using two NaI(Tl) crystals. The results were simulated with MCNP4c code calculations. The theoretical calculations and experimental measurements were in good agreement indicating that this method can be used for detection of explosives and illicit drugs.

  12. The neutron production rate measurement of an indigenously developed compact D-D neutron generator

    Directory of Open Access Journals (Sweden)

    Das Basanta Kumar

    2013-01-01

    Full Text Available One electrostatic accelerator based compact neutron generator was developed. The deuterium ions generated by the ion source were accelerated by one accelerating gap after the extraction from the ion source and bombarded to a target. Two different types of targets, the drive - in titanium target and the deuteriated titanium target were used. The neutron generator was operated at the ion source discharge potential at +Ve 1 kV that generates the deuterium ion current of 200 mA at the target while accelerated through a negative potential of 80 kV in the vacuum at 1.3×10-2 Pa filled with deuterium gas. A comparative study for the neutron yield with both the targets was carried out. The neutron flux measurement was done by the bubble detectors purchased from Bubble Technology Industries. The number of bubbles formed in the detector is the direct measurement of the total energy deposited in the detector. By counting the number of bubbles the total dose was estimated. With the help of the ICRP-74 neutron flux to dose equivalent rate conversion factors and the solid angle covered by the detector, the total neutron flux was calculated. In this presentation the operation of the generator, neutron detection by bubble detector and estimation of neutron flux has been discussed.

  13. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Parallel theoretical study of the two components of the prompt fission neutrons: Dynamically released at scission and evaporated from fully accelerated fragments

    Directory of Open Access Journals (Sweden)

    Carjan Nicolae

    2017-01-01

    Full Text Available Prompt fission neutrons (PFN angular and energy distributions for the reaction 235U(nth,f are calculated as a function of the mass asymmetry of the fission fragments using two extreme assumptions: 1 PFN are released during the neck rupture due to the diabatic coupling between the neutron degree of freedom and the rapidly changing neutron-nucleus potential. These unbound neutrons are faster than the separation of the nascent fragments and most of them leave the fissioning system in few 10−21 sec. i.e., at the begining of the acceleration phase. Surrounding the fissioning nucleus by a sphere one can calculate the radial component of the neutron current density. Its time integral gives the angular distribution with respect to the fission axis. The average energy of each emitted neutron is also calculated using the unbound part of each neutron wave packet. The distribution of these average energies gives the general trends of the PFN spectrum: the slope, the range and the average value. 2 PFN are evaporated from fully accelerated, fully equilibrated fission fragments. To follow the de-excitation of these fragments via neutron and γ-ray sequential emissions, a Monte Carlo sampling of the initial conditions and a Hauser-Feshbach statistical approach is used. Recording at each step the emission probability, the energy and the angle of each evaporated neutron one can construct the PFN energy and the PFN angular distribution in the laboratory system. The predictions of these two methods are finally compared with recent experimental results obtained for a given fragment mass ratio.

  15. Portable Neutron Generator with 9-Section Silicon $\\alpha $-Detector

    CERN Document Server

    Bystritsky, V M; Kadyshevskij, V G; Khasaev, T O; Kobzev, A P; Presnyakov, Yu K; Rogov,Yu N; Ryzhkov, V I; Sapozhnikov, M G; Sissakian, A N; Slepnev, V M; Zamyatin, N I

    2006-01-01

    The characteristics of the portable neutron generator with a built-in $\\alpha $-detector are presented. Based on the "tagged" neutron method (TNM) the generator ~is being used for identification of ~the hidden chemical compounds. One of the special features of such generators compared to generators traditionally used and produced in industry is that the generator is a source of monoenergetic "tagged" 14.1 MeV neutrons produced in the binary nuclear reaction $d+t \\to \\alpha $ (3.5 MeV) $+n$ (14.1~MeV). Unambiguous information about the time and direction of the neutron emitted from the target can be obtained by recording an $\\alpha $ particle by the multi-pixel $\\alpha $-detector placed inside the neutron tube. The study of the "tagged" neutron method (TNM) shows that the use of the ($\\alpha $--$\\gamma $) coincidence reduces the gamma background induced by scattered neutrons by a factor of more than 200, which allows the detection and identification of small quantities of explosives, drugs, and toxic agents. T...

  16. Sample dependent response of a LaCl{sub 3}:Ce detector in prompt gamma neutron activation analysis of bulk hydrocarbon samples

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A.; Khiari, F.Z. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Isab, A.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Khateeb-ur-Rehman,; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2013-08-11

    The response of a LaCl{sub 3}:Ce detector has been found to depend upon the hydrogen content of bulk samples in prompt gamma analysis using 14 MeV neutron inelastic scattering. The moderation of 14 MeV neutrons from hydrogen in the bulk sample produces thermal neutrons around the sample which ultimately excite chlorine capture gamma rays in the LaCl{sub 3}:Ce detector material. Interference of 6.11 MeV chlorine gamma rays from the detector itself with 6.13 MeV oxygen gamma rays from the bulk samples makes the intensity of the 6.13 MeV oxygen gamma ray peak relatively insensitive to variations in oxygen concentration. The strong dependence of the 1.95 MeV doublet chlorine gamma ray yield on hydrogen content of the bulk samples confirms fast neutron moderation from hydrogen in the bulk samples as a major source of production of thermal neutrons and chlorine gamma rays in the LaCl{sub 3}:Ce detector material. Despite their poor oxygen detection capabilities, these detectors have nonetheless excellent detection capabilities for hydrogen and carbon in benzene, butyl alcohol, propanol, propanic acid, and formic acid bulk samples using 14 MeV neutron inelastic scattering.

  17. Design of small ECR ion source for neutron generator

    International Nuclear Information System (INIS)

    Zhou Changgeng; Lou Benchao; Zu Xiulan; Yang Haisu; Xiong Riheng

    2003-01-01

    The principles, structures and characteristics of small ECR (Electron Cyclotron Resonance) ion source used in the neutron generator are introduced. The processes of the design and key technique and innovations are described. (authors)

  18. A single-beam deuteron compact accelerator for neutron generation

    International Nuclear Information System (INIS)

    Araujo, Wagner Leite; Campos, Tarcisio Passos Ribeiro de

    2011-01-01

    Portable neutron generators are devices composed by small size accelerators that produce neutrons through fusion between hydrogen isotopes. These reactions are characterized by appreciable cross section at energies at the tens of keV, which enables device portability. The project baselines follow the same physical and engineering principles of any other particle accelerators. The generator consists of a gas reservoir, apparatus for ion production, few electrodes to accelerate and focus the ion beam, and a metal hydride target where fusion reactions occur. Neutron generator applications include geophysical measurements, indus- trial process control, environmental, research, nation's security and mechanical structure analysis.This article presents a design of a compact accelerator for d-d neutron generators, describing the physical theory applied to the deuteron extraction system, and simulating the ion beam transport in the accelerator. (author)

  19. Elemental analysis using temporal gating of a pulsed neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, Sudeep

    2018-02-20

    Technologies related to determining elemental composition of a sample that comprises fissile material are described herein. In a general embodiment, a pulsed neutron generator periodically emits bursts of neutrons, and is synchronized with an analyzer circuit. The bursts of neutrons are used to interrogate the sample, and the sample outputs gamma rays based upon the neutrons impacting the sample. A detector outputs pulses based upon the gamma rays impinging upon the material of the detector, and the analyzer circuit assigns the pulses to temporally-based bins based upon the analyzer circuit being synchronized with the pulsed neutron generator. A computing device outputs data that is indicative of elemental composition of the sample based upon the binned pulses.

  20. Development of a compact D-D neutron generator

    Science.gov (United States)

    Huang, Z.-W.; Wang, J.-R.; Wei, Z.; Lu, X.-L.; Ma, Z.-W.; Ran, J.-L.; Zhang, Z.-M.; Yao, Z.-E.; Zhang, Y.

    2018-01-01

    A compact D-D neutron generator was developed at Lanzhou University, China. A duoplasmatron ion source was used to produce a higher-current deuteron beam. The deuteron beam could be accelerated up to 150 keV by a single accelerating gap, and bombarded on a pure molybdenum drive-in target to produce D-D fast neutron. A bias voltage between the target and the extraction-accelerating electrode was produced by a resistance to suppress the secondary electron from the target. The neutron generator has been operated for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 1.0-4.0 mA. EJ410 scintillator detector system was used to measure the fast neutron yields. D-D neutron yield could reach 2.48×108 n/s under the deuteron beam of 3 mA and 150 keV.

  1. A neutron dynamic therapy with a boron tracedrug UTX-51 using a compact neutron generator.

    Science.gov (United States)

    Hori, Hitoshi; Tada, Ryu; Uto, Yoshihiro; Nakata, Eiji; Morii, Takashi; Masuda, Kai

    2014-08-01

    We are developing a neutron dynamic therapy (NDT) with boron tracedrugs for a new mechanical-clearance treatment of pathotoxic misfolded, aggregated, and self-propagating prion-associated disease proteins. We present a compact neutron generator-based NDT using a boron tracedrug UTX-51. Our NDT is based on the weak thermal neutron-bombarded destructive action of UTX-51 on bovine serum albumin (BSA) using the neutron beams produced from a compact inertial electrostatic confinement fusion (IECF) neutron generator. BSA as an NDT molecular target was subjected to thermal neutron irradiation for eight hours using a compact neutron generator. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis pattern showed no protein band when 2 nmoles of BSA were irradiated with more than 100 nmoles of UTX-51, while BSA was not affected when irradiated without UTX-51. For the first time, we have succeeded in the molecular destruction of a prion-disease model protein, BSA, by NDT with a boron tracedrug, UTX-51, using a compact neutron generator. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  2. Target injection and engagement for neutron generation at 1 Hz

    International Nuclear Information System (INIS)

    Komeda, Osamu; Mori, Yoshitaka; Nishimura, Yasuhiko

    2013-01-01

    Target injection is a key technology to realizing inertial fusion energy. Here we present the first demonstration of target injection and neutron generation. We injected more than 600 spherical deuterated polystyrene (C 8 D 8 ) bead targets during 10 minutes at 1 Hz. After the targets fell for a distance of 18 cm, we applied the synchronized laser-diode-pumped ultra-intense laser HAMA and successfully generated neutrons repeatedly. The result is a step toward fusion power and also suggests possible industrial neutron sources. (author)

  3. Monte Carlo simulation of moderator and reflector in coal analyzer based on a D-T neutron generator.

    Science.gov (United States)

    Shan, Qing; Chu, Shengnan; Jia, Wenbao

    2015-11-01

    Coal is one of the most popular fuels in the world. The use of coal not only produces carbon dioxide, but also contributes to the environmental pollution by heavy metals. In prompt gamma-ray neutron activation analysis (PGNAA)-based coal analyzer, the characteristic gamma rays of C and O are mainly induced by fast neutrons, whereas thermal neutrons can be used to induce the characteristic gamma rays of H, Si, and heavy metals. Therefore, appropriate thermal and fast neutrons are beneficial in improving the measurement accuracy of heavy metals, and ensure that the measurement accuracy of main elements meets the requirements of the industry. Once the required yield of the deuterium-tritium (d-T) neutron generator is determined, appropriate thermal and fast neutrons can be obtained by optimizing the neutron source term. In this article, the Monte Carlo N-Particle (MCNP) Transport Code and Evaluated Nuclear Data File (ENDF) database are used to optimize the neutron source term in PGNAA-based coal analyzer, including the material and shape of the moderator and neutron reflector. The optimized targets include two points: (1) the ratio of the thermal to fast neutron is 1:1 and (2) the total neutron flux from the optimized neutron source in the sample increases at least 100% when compared with the initial one. The simulation results show that, the total neutron flux in the sample increases 102%, 102%, 85%, 72%, and 62% with Pb, Bi, Nb, W, and Be reflectors, respectively. Maximum optimization of the targets is achieved when the moderator is a 3-cm-thick lead layer coupled with a 3-cm-thick high-density polyethylene (HDPE) layer, and the neutron reflector is a 27-cm-thick hemispherical lead layer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Utilization of low voltage D-T neutron generators in neutron physics studies

    International Nuclear Information System (INIS)

    Singkarat, S.

    1995-01-01

    In a small nuclear laboratory of a developing country a low voltage D-T neutron generator can be a very useful scientific apparatus. Such machines have been used successfully for more than 40 years in teaching and scientific research. The original continuous mode 150-kV D-T neutron generator has been modified to have also a capability of producing 2-ns pulsed neutrons. Together with a carefully designed 10 m long flight path collimator and shielding of a 25 cm diameter · 10 cm thick BC-501 neutron detector, the pulsing system was successfully used for measuring the double differential cross-section (DDX) of natural iron for 14.1-MeV neutron from the angle of 30 deg to 150 deg in 10 deg steps. In order to extend the utility of the generator, two methods for converting the almost monoenergetic 14-MeV neutrons to monoenergetic neutrons of lower energy were proposed and tested. Both designs used the neutron-proton interaction at a circular surface-of-revolution made of hydrocarbon materials. The first design is for a pulsed neutron generator and the second design is for an ordinary continuous mode generator. The latter method was successfully used to measure the scintillation light output of a 1.4 cm diameter spherical NE-213 scintillation detector. The neutron generator has also been used in the continuous search for improved neutron detection techniques. There is a proposal, based on Monte Carlo calculations, of using a scintillation fiber for a fast neutron spectrometer. Due to the slender shape of the fiber, the pattern of produced light gives a peak in the pulse height spectrum instead of the well-known rectangular-like distribution, when the fiber is bombarded end-on by a beam of 14-MeV neutrons. Experimental investigations were undertaken. Detailed investigations on the light transportation property of a short fiber were performed. The predicted peak has not yet been found but the fiber detector may be developed as a directional discrimination fast neutron

  5. Pulsed White Spectrum Neutron Generator for Explosive Detection

    International Nuclear Information System (INIS)

    King, Michael J.; Miller, Gill T.; Reijonen, Jani; Ji, Qing; Andresen, Nord; Gicquel, Frederic; Kavlas, Taneli; Leung, Ka-Ngo; Kwan, Joe

    2008-01-01

    Successful explosive material detection in luggage and similar sized containers is a critical issue in securing the safety of all airline passengers. Tensor Technology Inc. has recently developed a methodology that will detect explosive compounds with pulsed fast neutron transmission spectroscopy. In this scheme, tritium beams will be used to generate neutrons with a broad energy spectrum as governed by the T(t,2n)4He fission reaction that produces 0-9 MeV neutrons. Lawrence Berkeley National Laboratory (LBNL), in collaboration with Tensor Technology Inc., has designed and fabricated a pulsed white-spectrum neutron source for this application. The specifications of the neutron source are demanding and stringent due to the requirements of high yield and fast pulsing neutron emission, and sealed tube, tritium operation. In a unique co-axial geometry, the ion source uses ten parallel rf induction antennas to externally couple power into a toroidal discharge chamber. There are 20 ion beam extraction slits and 3 concentric electrode rings to shape and accelerate the ion beam into a titanium cone target. Fast neutron pulses are created by using a set of parallel-plate deflectors switching between +-1500 volts and deflecting the ion beams across a narrow slit. The generator is expected to achieve 5 ns neutron pulses at tritium ion beam energies between 80-120 kV. First experiments demonstrated ion source operation and successful beam pulsing

  6. Neutron excess generation by fusion neutron source for self-consistency of nuclear energy system

    International Nuclear Information System (INIS)

    Saito, Masaki; Artisyuk, V.; Chmelev, A.

    1999-01-01

    The present day fission energy technology faces with the problem of transmutation of dangerous radionuclides that requires neutron excess generation. Nuclear energy system based on fission reactors needs fuel breeding and, therefore, suffers from lack of neutron excess to apply large-scale transmutation option including elimination of fission products. Fusion neutron source (FNS) was proposed to improve neutron balance in the nuclear energy system. Energy associated with the performance of FNS should be small enough to keep the position of neutron excess generator, thus, leaving the role of dominant energy producers to fission reactors. The present paper deals with development of general methodology to estimate the effect of neutron excess generation by FNS on the performance of nuclear energy system as a whole. Multiplication of fusion neutrons in both non-fissionable and fissionable multipliers was considered. Based on the present methodology it was concluded that neutron self-consistency with respect to fuel breeding and transmutation of fission products can be attained with small fraction of energy associated with innovated fusion facilities. (author)

  7. Effect of sample moisture and bulk density on performance of the 241Am-Be source based prompt gamma rays neutron activation analysis setup. A Monte Carlo study

    International Nuclear Information System (INIS)

    Almisned, Ghada

    2010-01-01

    Monte Carlo simulations were carried out using the dependence of gamma ray yield on the bulk density and moisture content for five different lengths of Portland cement samples in a thermal neutron capture based Prompt Gamma ray Neutron Activation Analysis (PGNAA) setup for source inside moderator geometry using an 241 Am-Be neutron source. In this study, yields of 1.94 and 6.42 MeV prompt gamma rays from calcium in the five Portland cement samples were calculated as a function of sample bulk density and moisture content. The study showed a strong dependence of the 1.94 and 6.42 MeV gamma ray yield upon the sample bulk density but a weaker dependence upon sample moisture content. For an order of magnitude increase in the sample bulk density, an order of magnitude increase in the gamma rays yield was observed, i.e., a one-to-one correspondence. In case of gamma ray yield dependence upon sample moisture content, an order of magnitude increase in the moisture content of the sample resulted in about 16-17% increase in the yield of 1.94 and 6.42 MeV gamma rays from calcium. (author)

  8. Prompt neutron emission from fragments in spontaneous fission of {sup 244,248}Cm and {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Vorobyev, A. S.; Shcherbakov, O. A. [Petersburg Nuclear Physics Institute, Gatchina, Leningrad district, 188300 (Russian Federation); Dushin, V. N.; Jakovlev, V. A.; Kalinin, V. A.; Petrov, B. F. [V.G. Khlopin Radium Institute, St. Petersburg, 194021 (Russian Federation); Hambsch, F.J [EC-JRC-Institute for Reference Materials and Measurements Retieseweg 111, B-2440 Geel (Belgium); Laptev, A. B. [Petersburg Nuclear Physics Institute, Gatchina, Leningrad district, 188300 (Russian Federation); Japan Nuclear Cycle Development Institute, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

    2005-07-01

    Neutrons emitted in fission were measured separately for each complementary fragment in correlation with fission fragment energies. Two high efficiency Gd-loaded liquid scintillator tanks were used for neutron registration. Fission fragment energies were measured using a twin Frisch gridded ionization chamber with a pin-hole collimator. The neutron multiplicity distributions were obtained for each value of the fission fragment mass and energy and corrected for neutron registration efficiency, background and pile-up. The dependencies of these distributions on fragment mass and energy for different energy and mass bins, as well as the mass and energy distribution of the fission fragments are presented and discussed. (authors)

  9. Characterization of a deuterium-deuterium plasma fusion neutron generator

    Science.gov (United States)

    Lang, R. F.; Pienaar, J.; Hogenbirk, E.; Masson, D.; Nolte, R.; Zimbal, A.; Röttger, S.; Benabderrahmane, M. L.; Bruno, G.

    2018-01-01

    We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14 . 1 MeV neutrons from deuterium-tritium fusion is found at a level of 3 . 5%, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage V 3 . 32 ± 0 . 14 and current I 0 . 97 ± 0 . 01. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.

  10. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    Langford, O.M.; Peelman, H.E.

    1978-01-01

    Means and method are described for energizing and regulating a neutron generator tube having a target, an ion source and a replenisher. It providing a negative high voltage to the target and monitoring the target current. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordence with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current

  11. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    1977-01-01

    A means and method for energizing and regulating a neutron generator tube is described. It has a target, an ion source and a replenisher. A negative high voltage is applied to the target and the target current monitored. A constant current from a constant current source is divided into a shunt current and a replenisher current in accordance with the target current. The replenisher current is applied to the replenisher in a neutron generator tube so as to control the neutron output in accordance with the target current. (C.F.)

  12. Spectral fluence of neutrons generated by radiotherapeutic Linacs

    International Nuclear Information System (INIS)

    Kralik, Miloslav; Solc, Jaroslav; Smoldasova, Jana; Vondracek, Vladimir; Farkasova, Estera; Ticha, Ivana

    2015-01-01

    Spectral fluences of neutrons generated in the heads of the radiotherapeutic linacs Varian Clinac 2100 C/D and Siemens ARTISTE were measured by means of the Bonner spheres spectrometer whose active detector of thermal neutrons was replaced by an activation detector, i.e. a tablet made of pure manganese. Measurements with different collimator settings reveal an interesting dependence of neutron fluence on the area defined by the collimator jaws. The determined neutron spectral fluences were used to derive ambient dose equivalent rate along the treatment coach. To clarify at which components of the linac neutrons are mainly created, the measurements were complemented with MCNPX calculations based on a realistic model of the Varian Clinac. (authors)

  13. Determination of boron in ceramic reference materials by prompt gamma activation analysis using focused neutron guided beam of JRR-3M

    International Nuclear Information System (INIS)

    Miura, T.; Kuroiwa, T.; Chiba, K.; Matsue, H.

    2008-01-01

    Prompt gamma activation analysis using a focused thermal neutron guided beam at JAEA JRR-3M was applied to the determination of B in ceramic certified reference materials (BAM CRM S-003 Silicon Carbide Powder and NMIJ CRM 8004-a Silicon Nitride Powder). Cl and Si were used as internal standards to obtain linear calibration curves of B. The analytical result of B in BAM CRM S-003 was in good agreement with the certified value. The relative expanded measurement uncertainties (k = 2) were 4.8% for BAM CRM S-003 and 4.9% for NMIJ CRM 8004-a. (author)

  14. Modification of Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Kim, Suk Kwon; Park, Chang Su; Jung, Nam Suk; Jung, Hwa Dong; Park, Ji Young; Hwang, Yong Seok; Choi, H. D.

    2005-01-01

    The prototype D-D neutron generator was modified in order to enhance the neutron yield. The distance from ion source to target was reduced to increase the ion beam current at target position. Thick Ti target was replaced by thin Ti target which was vacuum-deposited on Cu substrate in order to enhance the target cooling. Performance of the modified device was tested

  15. On generating neutron transport tables with the NJOY system

    International Nuclear Information System (INIS)

    Caldeira, Alexandre D.; Claro, Luiz H.

    2013-01-01

    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)

  16. Evaluation of spatial sensitivity of a prompt gamma neutron activation analysis facility for the in vivo determination of nitrogen in small animals

    International Nuclear Information System (INIS)

    Kasviki, K.; Ioannina University; Stamatelatos, I.E.; Kalef-Ezra, J.

    2007-01-01

    We investigated the spatial dependence of the sensitivity of nitrogen measurement with a prompt gamma neutron activation analysis (PGNAA) system for small animals and developed an analysis procedure that permits the reduction of systematic errors due to that dependence. The analysis procedure is based on neutron and photon transport calculations performed using the MCNP code in order to evaluate the sensitivity of the PGNAA facility. The system can be calibrated experimentally using a small number of phantoms of known size and composition. The calculation approach can then be used to predict responses for animal body sizes and shapes relatively to those experimentally determined and to include the effect of tissue inhomogeneities. Our calculations were verified by experimental measurements performed for a set of cylindrical inhomogeneous phantoms. The calculated to experimental ratios observed were within 6%. (author)

  17. Development of an experimental device based on the digitalization of the signal and dedicated to the characterization of fission fragments and prompt neutrons; Developpement d'un dispositif experimental base sur la digitalisation des signaux et dedie a la caracterisation des fragments de fission et des neutrons prompts emis

    Energy Technology Data Exchange (ETDEWEB)

    Varapai, N

    2006-12-15

    The present work demonstrates the application of the digital technique for nuclear measurements. This new technique is based on the digitalization of the signals from the detectors and has several advantages. This technique allows us to extract the maximum amount of information contained in the signal shape. In the case of an ionization chamber this signal contains the necessary information on the particle kinetic energy, emission angle and mass. This method has been implemented for measurements of promptly emitted fission neutrons in coincidence with fission fragments from {sup 252}Cf(sf). A double Frisch-grid ionization chamber is used as fission fragment detector. The promptly emitted neutrons are detected by a NE213 liquid scintillation detector. This work displays how delicate analysis of the digitalized signals permitted us to infer the mass and kinetic energy distributions of the fission fragments as well as the neutron energy spectrum and multiplicity. The outline of this thesis is as follows: Chapter 2 gives an overview of the experimental tools used in this work. Chapter 3 explains the analysis procedure of the digitalized anode signal from an ionization chamber. Chapter 4 gives a detailed explanation of the analysis procedure of the digitalized signal from a neutron detector. In Chapter 5 the analysis procedure of the fission fragment events in coincidence with neutrons is given.

  18. The intensive DT neutron generator of TU Dresden

    Directory of Open Access Journals (Sweden)

    Klix Axel

    2018-01-01

    Full Text Available TU Dresden operates an accelerator-based intensive DT neutron generator. Experimental activities comprise investigation into material activation and decay, neutron and photon transport in matter and R&D work on radiation detectors for harsh environments. The intense DT neutron generator is capable to produce a maximum of 1012 n/s. The neutron source is a solid-type water-cooled tritium target based on a titanium matrix on a copper carrier. The neutron yield at a typical deuteron beam current of 1 mA is of the order of 1011 n/s in 4Π. A pneumatic sample transport system is available for short-time irradiations and connected to wo high-purity germanium detector spectrometers for the measurement of induced activities. The overall design of the experimental hall with the neutron generator allows a flexible setup of experiments including the possibility of investigating larger structures and cooled samples or samples at high temperatures.

  19. Monte Carlo simulation of explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator.

    Science.gov (United States)

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    An explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator has been simulated using the Monte Carlo N-Particle Transport Code (MCNP5). Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma emission (10.82MeV) following radiative neutron capture by (14)N nuclei. The explosive detection system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF) driven ion source and nominal yield of about 10(10) fast neutrons per second (E=2.5MeV). Polyethylene and paraffin were used as moderators with borated polyethylene and lead as neutron and gamma ray shielding, respectively. The shape and the thickness of the moderators and shields are optimized to produce the highest thermal neutron flux at the position of the explosive and the minimum total dose at the outer surfaces of the explosive detection system walls. In addition, simulation of the response functions of NaI, BGO, and LaBr3-based γ-ray detectors to different explosives is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Online monitoring of fast neutron (DT/DD) at Purnima neutron generator

    International Nuclear Information System (INIS)

    Bishnoi, S.; Patel, T.; Shukla, M.; Adhikari, P.S.; Sinha, A.

    2012-01-01

    A neutron generator (NG) at Purnima Labs, BARC has been developed for DT accelerator driven zero power subcritical (ADSS) system. Subcritical core of ADSS will be coupled to the NG for benchmarking experiments. Kinetic parameters of ADSS such as K-source, flux, power etc depends on this external neutron source strength injected to the core. However the neutron emission rate of NG does not remain stable throughout its operation. In view of this a reliable, precise and online monitoring of NG's neutron emission rate is required. An online neutron monitoring system based on associated particle method has been designed, developed and installed at NG. The monitoring unit consists of an ion implanted planar silicon detector, placed inside the drift tube of NG at an angle with respect to D + beam direction. A series of experiments were carried out with increasing neutron yield to optimize the position of detector such that it has sufficient counting statistics and minimum pileup. A complementary calibration procedure for validating these results based on activation technique was also carried out with standard Cu foil. The reaction rate monitored with online monitor and foil activation technique were compared, their variations with the predicted (theoretical) results were within 16%. This paper deals with the development and performance of online neutron monitoring system for DT and DD neutrons

  1. Spatial distribution of neutron flux for the A-711 neutron generator

    International Nuclear Information System (INIS)

    Essiet, A. E.; Owolabi, S. A.; Adesanmi, C. A.; Balogun, F. A.

    1996-01-01

    The spatial distribution of neutron flux for the Kaman sciences A-711 neutron generator recently installed at the Centre for Energy Research and Development (CERD), Ile-Ife Nigeria has been determined. At an operational tube current of 2.0 mA and high voltage power supply (HVPS) of 158 kV, the neutron flux increases from 1.608 ± 0.021*10 8 n/cm 2 s at the top of the irradiated plastic vial to 2.640 ± 0.022*10 8 n/cm 2 s at the centre, and then decreases to 1.943 ± 0.02* 8 n/cm 2 s at the bottom. The flux density is strongly dependent on the diameter of deuteron at the tritium target, and within this range a source strength of 10 8 n/s has been measured for the A-711 neutron generator

  2. Calculation of Spectra of Neutrons and Charged Particles Produced in a Target of a Neutron Generator

    Science.gov (United States)

    Gaganov, V. V.

    2017-12-01

    An algorithm for calculating the spectra of neutrons and associated charged particles produced in the target of a neutron generator is detailed. The products of four nuclear reactions 3H( d, n)4He, 2H( d, n)3He, 2H( d, p)3H, and 3He( d, p)4He are analyzed. The results of calculations are presented in the form of neutron spectra for several emission angles and spectra of associated charged particles emitted at an angle of 180° for a deuteron initial energy of 0.13 MeV.

  3. Means and method for controlling the neutron output of a neutron generator tube

    International Nuclear Information System (INIS)

    1980-01-01

    A specification is given for an energizing and regulating circuit for a gas filled neutron generator tube consisting of a target, an ion source and a replenisher, the circuit consisting of a power supply to provide a negative high voltage to the target and a target current corresponding to the neutron output of the tube, a constant current source, and control means connected to the power supply and to the constant current source, the control means being responsive to the target current to provide a portion of the constant current to the replenisher substantially to regulate the neutron output of the tube. (author)

  4. Neutron lifetime and generation time by KENO IV

    International Nuclear Information System (INIS)

    Hayashi, Masatoshi

    1991-01-01

    It is believed that Monte Carlo method is suitable to the calculation of neutron lifetime and generation time with reference to the life cycle viewpoint. This paper illustrates that those times obtained by Monte Carlo method are quite different from the results by perturbation method. The neutron lifetime and the generation time for bare and reflected reactors were investigated by the Monte Carlo program, KENO IV. the Monte Carlo procedure is based on tracking and recording the life history of neutrons in a realistic fashion in a fissionable system with minimum nuclear and geometric approximations. The KENO IV provides the multiplication factor, neutron lifetime and generation time simultaneously. The thermal spherical reactors for both bare and reflected reactors were studied using the KENO IV. The reflected reactor is surrounded with 30 cm thick light water. The atomic densities in the regions and the calculated results of the multiplication factor, neutron lifetime and generation time are given. The different definitions of these times between the Monte Carlo method and perturbation theory caused the difference of the results. (K.I.)

  5. The shielding of a 14 MeV neutron generator

    International Nuclear Information System (INIS)

    Brighton, D.R.

    1976-10-01

    The concrete masonry shield for a 14 MeV neutron generator was designed using data supplied by the manufacturer. Subsequent radiation surveys outside the shield showed doses higher than expected. Calculations indicated the sensitivity of dose transmission factors to concrete composition. The observed dose transmission factor agreed with that of Broerse but not with that of Hacke and Prudhomme. Measurements and calculations delineated the contribution that neutrons, scattered from the upper wall that supports the laboratory roof, made to the dose in adjoining areas. In redesigning the shield a compromise was made between additional cost and restrictions on the generator's duty cycle, which is automatically controlled to ensure personnel safety. (Author)

  6. Sustaining knowledge in the neutron generator community and benchmarking study.

    Energy Technology Data Exchange (ETDEWEB)

    Barrentine, Tameka C.; Kennedy, Bryan C.; Saba, Anthony W.; Turgeon, Jennifer L.; Schneider, Julia Teresa; Stubblefield, William Anthony; Baldonado, Esther

    2008-03-01

    In 2004, the Responsive Neutron Generator Product Deployment department embarked upon a partnership with the Systems Engineering and Analysis knowledge management (KM) team to develop knowledge management systems for the neutron generator (NG) community. This partnership continues today. The most recent challenge was to improve the current KM system (KMS) development approach by identifying a process that will allow staff members to capture knowledge as they learn it. This 'as-you-go' approach will lead to a sustainable KM process for the NG community. This paper presents a historical overview of NG KMSs, as well as research conducted to move toward sustainable KM.

  7. Beam splitting to improve target life in neutron generators

    International Nuclear Information System (INIS)

    Farrell, J.P.

    1976-01-01

    In a neutron generator in which a tritium-titanium target is bombarded by a deuterium ion beam, the target half-life is increased by separating the beam with a weak magnetic field to provide three separate beams of atomic, diatomic, and triatomic deuterium ions which all strike the target at different adjacent locations. Beam separation in this manner eliminates the problem of one type ion impairing the neutron generating efficiency of other type ions, thereby effecting more efficient utilization of the target material

  8. ITEP Subcritical Neutron Generator driven by charged particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shvedov, O.V.; Chuvilo, I.V.; Vasiliev, V.V. [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation)] [and others

    1995-10-01

    A research facility prototype including a combination of a linear accelerator, a neutron generating target, a nuclear safety ensuring and means of its attainment for Subcritical Neutron Generator are considered. The scheme of the multiplying is shown. The assembly will be mounted in the body of the partly dismantled ITEP HWR. Requirements for subcritical assembly are worked out and their feasibility within the framework of the heavy-water blanket is shown. The facility`s application as a full-scale model of more powerful installations of this kind and for fundamental experimental research has been investigated.

  9. A Dosimetry Study of Deuterium-Deuterium Neutron Generator-based In Vivo Neutron Activation Analysis.

    Science.gov (United States)

    Sowers, Daniel; Liu, Yingzi; Mostafaei, Farshad; Blake, Scott; Nie, Linda H

    2015-12-01

    A neutron irradiation cavity for in vivo neutron activation analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator that produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 × 10(8) ± 30% s(-1). A moderator/reflector/shielding [5 cm high density polyethylene (HDPE), 5.3 cm graphite and 5.7 cm borated (HDPE)] assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeters (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and the photon dose was measured by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10-min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 ± 0.8 mSv for neutrons and 4.2 ± 0.2 mSv for photons for 10 min; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population.

  10. The intense neutron generator and future factory type ion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1968-07-01

    A neutron factory is likely to sell its product in the form of isotopes. To ay neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scale for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising. (author)

  11. The intense neutron generator and future factory type ion accelerators

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1968-01-01

    A neutron factory is likely to sell its product in the form of isotopes. To ay neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scale for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising. (author)

  12. Multi detector input and function generator for polarized neutron experiments

    International Nuclear Information System (INIS)

    De Blois, J.; Beunes, A.J.H.; Ende, P. v.d.; Osterholt, E.A.; Rekveldt, M.T.; Schipper, M.N.; Velthuis, S.G.E. te

    1998-01-01

    In this paper a VME module is described for static or stroboscopic measurements with a neutron scattering instrument, consisting essentially of a series of up to 64 3 He neutron detectors around a sample environment. Each detector is provided with an amplifier and a discriminator to separate the neutrons from noise. To reduce the wiring, the discriminator outputs are connected to the module by coding boxes. Two 16-inputs to one-output coding boxes generate serial output codes on a fiber optic connection. This basically fast connection reduces the dead time introduced by the coding, and the influence of environmental noise. With stroboscopic measurements a periodic function is used to affect the sample surrounded by a field coil. Each detected neutron is labeled with a data label containing the detector number and the time of detection with respect to a time reference. The data time base can be programmed on a linear or a nonlinear scale. An external source or an attribute of the periodic function may generate the time reference pulse. A 12-bit DAC connected to the output of an 8 K, 16-bits memory, where the pattern of the current has been stored before, generates the function. The function memory is scanned by the programmable function time base. Attributes are set by the four remaining bits of the memory. One separate detector input connects a monitor detector in the neutron beam with a 32-bit counter/timer that provides measuring on a preset count, preset time or preset frame. (orig.)

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

    CERN Document Server

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

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

  14. Nuclear data and measurements series: Ratio of the prompt-fission-neutron spectrum of plutonium 239 to that of uranium 235

    International Nuclear Information System (INIS)

    Sugimoto, M.; Smith, A.B.; Guenther, P.T.

    1986-09-01

    The prompt-fission-neutron spectrum resulting from 239 Pu fission induced by 0.55 MeV incident neutrons is measured from 1.0 to 10.0 MeV relative to that of 235 U fission induced by the same incident-energy neutrons. The measurements employ the time-of-flight technique. Energy-dependent ratios of the two spectra are deduced from the measured values over the energy range 1.0 to 10.0 MeV. The experimentally-derived ratio results are compared with those calculated from ENDF/B-V, revision-2, and with results of recent microscopic measurements. Using the ENDF/B-V 235 U Watt parameters for the 235 U spectrum, the experimental measurements imply a ratio of average fission-spectrum energies of 239 Pu/ 235 U = 1.045 +- 0.003, compared to the value 1.046 calculated from ENDF/B-V, revision 2. 12 refs., 2 figs., 2 tabs

  15. Neutron radiation characteristics of the IVth generation reactor spent fuel

    Science.gov (United States)

    Bedenko, Sergey; Shamanin, Igor; Grachev, Victor; Knyshev, Vladimir; Ukrainets, Olesya; Zorkin, Andrey

    2018-03-01

    Exploitation of nuclear power plants as well as construction of new generation reactors lead to great accumulation of spent fuel in interim storage facilities at nuclear power plants, and in spent fuel «wet» and «dry» long-term storages. Consequently, handling the fuel needs more attention. The paper is focused on the creation of an efficient computational model used for developing the procedures and regulations of spent nuclear fuel handling in nuclear fuel cycle of the new generation reactor. A Thorium High-temperature Gas-Cooled Reactor Unit (HGTRU, Russia) was used as an object for numerical research. Fuel isotopic composition of HGTRU was calculated using the verified code of the MCU-5 program. The analysis of alpha emitters and neutron radiation sources was made. The neutron yield resulting from (α,n)-reactions and at spontaneous fission was calculated. In this work it has been shown that contribution of (α,n)-neutrons is insignificant in case of such (Th,Pu)-fuel composition and HGTRU operation mode, and integral neutron yield can be approximated by the Watt spectral function. Spectral and standardized neutron distributions were achieved by approximation of the list of high-precision nuclear data. The distribution functions were prepared in group and continuous form for further use in calculations according to MNCP, MCU, and SCALE.

  16. Radiation protection aspects of a high flux, fast neutron generator

    International Nuclear Information System (INIS)

    DeLuca, P.M.; Torti, R.P.; Chenevert, G.M.; Tesmer, J.R.; Kelsey, C.A.

    1976-01-01

    During the development and operation of a gas target, DT neutron generator for use in cancer therapy, two radiation hazards were routinely encountered - personnel exposure to neutrons and to tritium. The principal hazard was irradiation by fast neutrons. By assembling the source below ground level, adding shielding and the use of a controlled access, key identification interlock, the neutron hazard has been reduced. With the present source strength of 2 x 10 12 n/sec, an average neutron dose rate in the control room of 20 mrem/hr was measured- a level compatible with a limited run schedule. The second hazard was exposure to tritium in both gaseous and solid forms. A target inventory of 90 Ci, and overall inventory of 500 Ci, and the need to modify and repair the generator present significant potential hazard due to tritium exposure. The use of protective gloves, wipe tests, urine assays, continuous room air monitoring, and equipment decontamination minimized personnel exposure and effectively confined contamination. The dose due to tritium has been ∼ 0.5 rem/year and negligible spread of contamination has occurred

  17. Prompt nuclear analysis bibliography 1976

    International Nuclear Information System (INIS)

    Bird, J.R.; Campbell, B.L.; Cawley, R.J.

    1978-05-01

    A prompt nuclear analysis bibliography published in 1974 has been updated to include literature up to the end of 1976. The number of publications has more than doubled since mid-1973. The bibliography is now operated as a computer file and searches can be made on key words and parameters. Tables of references are given for each of the categories: backscattering, ion-ion, ion-gamma, ion-neutron, neutron-gamma, neutron-neutron and gamma-ray-induced reactions

  18. Proton Neutron Gamma-X Detection (PNGXD): An introduction to contrast agent detection during proton therapy via prompt gamma neutron activation

    Science.gov (United States)

    Gräfe, James L.

    2017-09-01

    Proton therapy is an alternative external beam cancer treatment modality to the conventional linear accelerator-based X-ray radiotherapy. An inherent by-product of proton-nuclear interactions is the production of secondary neutrons. These neutrons have long been thought of as a secondary contaminant, nuisance, and source of secondary cancer risk. In this paper, a method is proposed to use these neutrons to identify and localize the presence of the tumor through neutron capture reactions with the gadolinium-based MRI contrast agent. This could provide better confidence in tumor targeting by acting as an additional quality assurance tool of tumor position during treatment. This effectively results in a neutron induced nuclear medicine scan. Gadolinium (Gd), is an ideal candidate for this novel nuclear contrast imaging procedure due to its unique nuclear properties and its widespread use as a contrast agent in MRI. Gd has one of the largest thermal neutron capture cross sections of all the stable nuclides, and the gadolinium-based contrast agents localize in leaky tissues and tumors. Initial characteristics of this novel concept were explored using the Monte Carlo code MCNP6. The number of neutron capture reactions per Gy of proton dose was found to be approximately 50,000 neutron captures/Gy, for a 8 cm3 tumor containing 300 ppm Gd at 8 cm depth with a simple simulation designed to represent the active delivery method. Using the passive method it is estimated that this number can be up to an order of magnitude higher. The thermal neutron distribution was found to not be localized within the spread out Bragg peak (SOBP) for this geometrical configuration and therefore would not allow for the identification of a geometric miss of the tumor by the proton SOBP. However, this potential method combined with nuclear medicine imaging and fused with online CBCT and prior MRI or CT imaging could help to identify tumor position during treatment. More computational and

  19. Elemental Characterization of Single-Wall Carbon Nanotube Certified Reference Material by Neutron and Prompt gamma Activation Analysis

    Czech Academy of Sciences Publication Activity Database

    Kučera, Jan; Bennett, J. W.; Oflaz, R.; Paul, R. L.; De Nadai Fernandes, E. A.; Kubešová, Marie; Bacchi, M. A.; Stopic, A. J.; Sturgeon, R. E.; Grinberg, P.

    2015-01-01

    Roč. 87, č. 7 (2015), s. 3699-3705 ISSN 0003-2700 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : Neutron Activation Analyses * nanotechnology * Carbon nanotubes * Chemical activation * Single-walled carbon nanotubes (SWCN) Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 5.886, year: 2015

  20. Manual for troubleshooting and upgrading of neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-01

    This manual is intended to assist operators in troubleshooting and upgrading of neutron generators. It is directed particularly to operators and technicians in less experienced laboratories and therefore the descriptions of the principles and techniques of these machines are operator oriented. In addition to a discussion of the main characteristics of neutron generators, detailed information is given on the function of particular commercial units, on common problems related to specific components of accelerators, and on methods of troubleshooting and repair. Detailed schematic and circuit diagrams are provided to help operators in the development and improvement of the generators. The problems treated in the Manual have been collected during several IAEA missions in developing countries. 125 refs, 161 figs, 22 tabs.

  1. Manual for troubleshooting and upgrading of neutron generators

    International Nuclear Information System (INIS)

    1996-11-01

    This manual is intended to assist operators in troubleshooting and upgrading of neutron generators. It is directed particularly to operators and technicians in less experienced laboratories and therefore the descriptions of the principles and techniques of these machines are operator oriented. In addition to a discussion of the main characteristics of neutron generators, detailed information is given on the function of particular commercial units, on common problems related to specific components of accelerators, and on methods of troubleshooting and repair. Detailed schematic and circuit diagrams are provided to help operators in the development and improvement of the generators. The problems treated in the Manual have been collected during several IAEA missions in developing countries. 125 refs, 161 figs, 22 tabs

  2. Neutron monitor generated data distributions in quantum variational Monte Carlo

    Science.gov (United States)

    Kussainov, A. S.; Pya, N.

    2016-08-01

    We have assessed the potential applications of the neutron monitor hardware as random number generator for normal and uniform distributions. The data tables from the acquisition channels with no extreme changes in the signal level were chosen as the retrospective model. The stochastic component was extracted by fitting the raw data with splines and then subtracting the fit. Scaling the extracted data to zero mean and variance of one is sufficient to obtain a stable standard normal random variate. Distributions under consideration pass all available normality tests. Inverse transform sampling is suggested to use as a source of the uniform random numbers. Variational Monte Carlo method for quantum harmonic oscillator was used to test the quality of our random numbers. If the data delivery rate is of importance and the conventional one minute resolution neutron count is insufficient, we could always settle for an efficient seed generator to feed into the faster algorithmic random number generator or create a buffer.

  3. Pathways to agility in the production of neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Stoltz, R.E. [Sandia National Labs., Livermore, CA (United States); Beavis, L.C.; Cutchen, J.T.; Garcia, P.; Gurule, G.A.; Harris, R.N.; McKey, P.C.; Williams, D.W. [Sandia National Labs., Albuquerque, NM (United States)

    1994-02-01

    This report is the result of a study team commissioned to explore pathways for increased agility in the manufacture of neutron generators. As a part of Sandia`s new responsibility for generator production, the goal of the study was to identify opportunities to reduce costs and increase flexibility in the manufacturing operation. Four parallel approaches (or pathways) were recommended: (1) Know the goal, (2) Use design leverage effectively, (3) Value simplicity, and (4) Configure for flexibility. Agility in neutron generator production can be enhanced if all of these pathways are followed. The key role of the workforce in achieving agility was also noted, with emphasis on ownership, continuous learning, and a supportive environment.

  4. Current Status and Progress of Developing a D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In-Jung; Jung, Hwa-Dong; Park, Chang-Su; Jung, Nam-Suk; Chung, Kyoung-Jae; Hwang, Yong-Seok; Choi, H. D.

    2006-01-01

    The research to develop a D-D neutron generator was begun in 2001. A prototype device was built in 2004, and partly modified in 2005. By using the modified prototype D-D neutron generator, neutron generation runs were performed, and the characteristics of D-D neutron generation was investigated. The final goal of maximum neutron yield is 10 8 n/s, while a yield of 6.5x10 7 n/s has been achieved. Here, the results of neutron generation runs performed by using the modified prototype device are summarized, and the feature of a new ion source to be tested in weeks is briefly described

  5. A Proposal for a Next Generation European Neutron Source

    International Nuclear Information System (INIS)

    Andersen, K.H.; Carlile, C.J.

    2016-01-01

    We argue that it is not too early to begin the planning process for a next generation neutron source for Europe, even as the European Spallation Source is being constructed. We put forward three main arguments. Firstly, nowadays the period between the first scientific concept of a new facility being proposed and its actual realisation is approaching half a century. We show evidence for this. Secondly, there is a straightforward development of the short pulse/long pulse spallation concepts that will deliver gains in neutron brightness of more than a factor 30 over what the ESS will soon deliver and provide the optimum balance between resolution and intensity. We describe our concept, which is a spallation source where the proton pulse length is matched to the moderating time of slow neutrons. Thirdly, when we look at our colleagues in astronomy and high energy physics, we see that they have a totally different, more global and more ambitious approach to the coming generations of large facilities. We argue that it is time for the neutron community not simply to rest upon its laurels and take what is given but to be proactive.. (paper)

  6. The first IEC fusion industrial neutron generator and developments

    Science.gov (United States)

    Sved, John

    1999-06-01

    Inertial Electrostatic Confinement fusion grade plasma containment has been sporadically researched since the early 1960's. In the 1990's the work of G. H. Miley and his team at the University of Illinios, Fusion Studies Laboratory, Champaign-Urbana has stimulated a collaboration with industry. The development and test program for the first industrial IEC neutron generator has progressed to the point where an endurance test is under way to demonstrate at least 10,000 hours of operational life of the sealed chamber device without servicing. The market entry goals of steady 107 D-D n/s CW output with an air-cooled system have been achieved. DASA has invested in the development of the industrial product and the continuing basic research at the UI-FSL. The complete DASA FusionStar IEC-PS1 point source neutron generator set is described with emphasis on the interfaces to user NAA systems. The next product developments are pulsed neutron operations and higher fusion reaction rates of up to 1010 by means of affordable add-ons to the basic IEC-PS system. The production engineering experience gained will next be applied to a more challenging line source variant of the IEC. Beyond neutron and proton sources, several other IEC applications are being developed.

  7. Shielding evaluation of neutron generator hall by Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pujala, U.; Selvakumaran, T.S.; Baskaran, R.; Venkatraman, B. [Radiological Safety Division, Indira Gandhi Center for Atomic Research, Kalpakkam (India); Thilagam, L.; Mohapatra, D.K., E-mail: swathythila2@yahoo.com [Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam (India)

    2017-04-01

    A shielded hall was constructed for accommodating a D-D, D-T or D-Be based pulsed neutron generator (NG) with 4π yield of 10{sup 9} n/s. The neutron shield design of the facility was optimized using NCRP-51 methodology such that the total dose rates outside the hall areas are well below the regulatory limit for full occupancy criterion (1 μSv/h). However, the total dose rates at roof top, cooling room trench exit and labyrinth exit were found to be above this limit for the optimized design. Hence, additional neutron shielding arrangements were proposed for cooling room trench and labyrinth exits. The roof top was made inaccessible. The present study is an attempt to evaluate the neutron and associated capture gamma transport through the bulk shields for the complete geometry and materials of the NG-Hall using Monte Carlo (MC) codes MCNP and FLUKA. The neutron source terms of D-D, D-T and D-Be reactions are considered in the simulations. The effect of additional shielding proposed has been demonstrated through the simulations carried out with the consideration of the additional shielding for D-Be neutron source term. The results MC simulations using two different codes are found to be consistent with each other for neutron dose rate estimates. However, deviation up to 28% is noted between these two codes at few locations for capture gamma dose rate estimates. Overall, the dose rates estimated by MC simulations including additional shields shows that all the locations surrounding the hall satisfy the full occupancy criteria for all three types of sources. Additionally, the dose rates due to direct transmission of primary neutrons estimated by FLUKA are compared with the values calculated using the formula given in NCRP-51 which shows deviations up to 50% with each other. The details of MC simulations and NCRP-51 methodology for the estimation of primary neutron dose rate along with the results are presented in this paper. (author)

  8. In-Situ Compositional Analysis and Provenance Study of the Historic Terengganu Stone (“Batu Bersurat Piagam Terengganu”) Using Neutron-Induced Prompt Gamma-Ray Techniques

    International Nuclear Information System (INIS)

    Abdullah, J.; Yahya, R.; Dahing, N. S.; Shaari, M. R.; Mahmood, A. A.; Hassan, H.; Jamaluddin, T. A.; Abdullah, M. Y.; Mahmud, N. A.; Mosorov, V.

    2018-01-01

    Terengganu inscribed stone is the oldest artifact with Jawi writing on it. It is a most treasured heritage for the history of Malaysian civilisation. The artifact proves that the Kingdom of Terengganu exist earlier than 1326 or 1386. It was accidentally discovered near Tersat River at Kampong Buluh, Kuala Berang, Terengganu, Malaysia by a gold & tin trader after a flash flood hit Kuala Berang in 1902.The inscription turned out to be a proclamation issued by the ''Sri Paduka Tuan'' of Terengganu. The significant is the date on the first face of the inscription, which is given as the year 1303 AD. This project focuses on the development of in-situ compositional analysis and provenance study of the Inscribed Terengganu Stone using Neutron-Induced Prompt Gamma-Ray Techniques (NIPGAT). To date, a lot of studies have been carried out by historians and archaeologists about the content of the inscription, but no scientific investigation about the material composition and its provenance has been performed. In this project, an instrumental analysis NIPGAT was designed as a portable non-destructive investigation tool employing an isotopic neutron source (Cf-252) and a gamma-ray spectroscopy system for in-situ investigation of the Inscribed Stone. (author)

  9. Neutron induced prompt gamma-ray technique for investigation the moisture and soluble salt problem in the historical building

    International Nuclear Information System (INIS)

    Lahasen Norman Shah Dahing; Ismail Mustapha; Jaafar Abdullah; Susan Maria Sipaun

    2006-01-01

    The degradation of some building materials such as brick and mortar is a major problem for the preservation of monuments or historic structures, especially where it is desirable to preserve the original fabric of the building. Such degradation often arises from the presence of contaminants in the constituent materials. In building materials, water is a major course of deterioration, both by acting as a solvent for various building materials components and by exerting stresses on the structure during thermal cycle. The soluble salts, notably chlorides, damage the structure either by periodically dissolving and recrystallising within the pores or by promoting corrosion. Knowledge of the presence and distribution of contaminants is needed for effective treatment and preservation. However, most of techniques have been use to evaluate the deterioration of historic building and structure is generally limited to visual observation and destructive tests of core samples. Some non-destructive testing (NDT) methods like electrical conductivity technique and ultrasonic testing, can identify cracks and voids, but cannot provide any information on the possible causes of these problems. To overcome this limitation, a new method, called n eutron-induced prompt gamma-ray technique (NIPGAT) has being developed at MINT for preservation of monuments and historic buildings. This method is useful for analytical techniques for identification both qualitative and quantitative multi-element analysis of major, minor and trace element of present in the sample. For many elements and applications, this technique offers high sensitivity, accuracy and reliability compare to other conventional method. (Author)

  10. Superpower proton linear accelerators for neutron generators and electronuclear facilities

    International Nuclear Information System (INIS)

    Lazarev, N.V.; Kozodaev, A.M.

    2000-01-01

    The report is a review of projects on the superpower proton linear accelerators (SPLA) for neutron generators (NG) and electronuclear facilities, proposed in the recent years. The beam average output capacity in these projects reaches 100 MW. The basic parameters of certain operating NGs, as well as some projected NGs will the SPLA drivers are presented. The problems on application of superconducting resonators in the SPLA as well as the issues of the SPLA reliability and costs are discussed [ru

  11. A liquid hydrocarbon deuteron source for neutron generators

    Science.gov (United States)

    Schwoebel, P. R.

    2017-06-01

    Experimental studies of a deuteron spark source for neutron generators using hydrogen isotope fusion reactions are reported. The ion source uses a spark discharge between electrodes coated with a deuterated hydrocarbon liquid, here Santovac 5, to inhibit permanent electrode erosion and extend the lifetime of high-output neutron generator spark ion sources. Thompson parabola mass spectra show that principally hydrogen and deuterium ions are extracted from the ion source. Hydrogen is the chief residual gas phase species produced due to source operation in a stainless-steel vacuum chamber. The prominent features of the optical emission spectra of the discharge are C+ lines, the hydrogen Balmer Hα-line, and the C2 Swan bands. Operation of the ion source was studied in a conventional laboratory neutron generator. The source delivered an average deuteron current of ˜0.5 A nominal to the target in a 5 μs duration pulse at 1 Hz with target voltages of -80 to -100 kV. The thickness of the hydrocarbon liquid in the spark gap and the consistency thereof from spark to spark influences the deuteron yield and plays a role in determining the beam-focusing characteristics through the applied voltage necessary to break down the spark gap. Higher breakdown voltages result in larger ion beam spots on the target and vice-versa. Because the liquid self-heals and thereby inhibits permanent electrode erosion, the liquid-based source provides long life, with 104 pulses to date, and without clear evidence that, in principle, the lifetime could not be much longer. Initial experiments suggest that an alternative cylindrical target-type generator design can extract approximately 10 times the deuteron current from the source. Preliminary data using the deuterated source liquid as a neutron-producing target are also presented.

  12. The neutrons generator becomes miniature; Le generateur de neutrons se miniaturise

    Energy Technology Data Exchange (ETDEWEB)

    Boulben, A

    2005-05-01

    A mini neutrons generator has been designed by researchers of the California university of Los Angeles which does not need any high voltage power supply ar any radioactive element. The system comprises a tubular vacuum chamber of few tenths of cm filled up with gaseous deuterium at very low pressure (0.7 Pa) and an erbium deuteride (ErD{sub 3}) screen. A lithium tantalate (LiTaO{sub 3}) pyroelectric crystal and a tungsten electrode are used to ionize and accelerate the gaseous deuterium with a minimum energy need. The collision of deuterium ions with the screen generates a maximum flow rate of about a thousand neutrons per second. Short paper. (J.S.)

  13. An intense neutron generator based on a proton accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G A; Milton, J C.D.; Vogt, E W

    1964-07-01

    A study has been made of the demand for a neutron facility with a thermal flux of {>=} 10{sup 16} n cm{sup -2} sec{sup -1} and of possible methods of producing such fluxes with existing or presently developing technology. Experimental projects proposed by neutron users requiring high fluxes call for neutrons of all energies from thermal to 100 MeV with both continuous-wave and pulsed output. Consideration of the heat generated in the source per useful neutron liberated shows that the (p,xn) reaction with 400 1000 MeV bombarding energies and heavy element targets (e.g. bismuth, lead) is capable of greater specific source strength than other possible methods realizable within the time scale. A preliminary parameter optimization carried through for the accelerator currently promising greatest economy (the separated orbit cyclotron or S.O.C.), reveals that a facility delivering a proton beam of about 65 mA at about 1 BeV would satisfy the flux requirement with a neutron cost significantly more favourable than that projected for a high flux reactor. It is suggested that a proton storage ring providing post-acceleration pulsing of the proton beam should be developed for the facility. With this elaboration, and by taking advantage of the intrinsic microscopic pulse structure provided by the radio frequency duty cycle, a very versatile source may be devised capable of producing multiple beams of continuous and pulsed neutrons with a wide range of energies and pulse widths. The source promises to be of great value for high flux irradiations and as a pilot facility for advanced reactor technology. The proposed proton accelerator also constitutes a meson source capable of producing beams of {pi} and {mu} mesons and of neutrinos orders of magnitude more intense than those of any accelerator presently in use. These beams, which can be produced simultaneously with the neutron beams, open vast areas of new research in fundamental nuclear structure, elementary particle physics

  14. An intense neutron generator based on a proton accelerator

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Milton, J.C.D.; Vogt, E.W.

    1964-01-01

    A study has been made of the demand for a neutron facility with a thermal flux of ≥ 10 16 n cm -2 sec -1 and of possible methods of producing such fluxes with existing or presently developing technology. Experimental projects proposed by neutron users requiring high fluxes call for neutrons of all energies from thermal to 100 MeV with both continuous-wave and pulsed output. Consideration of the heat generated in the source per useful neutron liberated shows that the (p,xn) reaction with 400 1000 MeV bombarding energies and heavy element targets (e.g. bismuth, lead) is capable of greater specific source strength than other possible methods realizable within the time scale. A preliminary parameter optimization carried through for the accelerator currently promising greatest economy (the separated orbit cyclotron or S.O.C.), reveals that a facility delivering a proton beam of about 65 mA at about 1 BeV would satisfy the flux requirement with a neutron cost significantly more favourable than that projected for a high flux reactor. It is suggested that a proton storage ring providing post-acceleration pulsing of the proton beam should be developed for the facility. With this elaboration, and by taking advantage of the intrinsic microscopic pulse structure provided by the radio frequency duty cycle, a very versatile source may be devised capable of producing multiple beams of continuous and pulsed neutrons with a wide range of energies and pulse widths. The source promises to be of great value for high flux irradiations and as a pilot facility for advanced reactor technology. The proposed proton accelerator also constitutes a meson source capable of producing beams of π and μ mesons and of neutrinos orders of magnitude more intense than those of any accelerator presently in use. These beams, which can be produced simultaneously with the neutron beams, open vast areas of new research in fundamental nuclear structure, elementary particle physics, and perhaps also in

  15. Evaluation of an in vivo prompt gamma neutron activation facility for body composition studies in critically ill intensive care patients: results on 41 normals

    International Nuclear Information System (INIS)

    Beddoe, A.H.; Streat, S.J.; Hill, G.L.

    1984-01-01

    A programme of metabolic and nutritional research is being undertaken in critically ill patients requiring intensive care. Central to this research is the measurement of the three nutritionally important compartments of body composition, protein, fat, and water by a combination of tritium dilution and prompt gamma in vivo neutron activation analysis (IVNAA). In this paper a calibration technique is presented that enables absolute estimates of total body nitrogen (TBN) to be made using prompt gamma IVNAA in critically ill patients with gross abnormalities in body composition, especially in their state of hydration. This technique, which is independent of skinfold anthropometry and does not make a priori assumptions about the ratios of major body compartments, has been applied to 41 normal volunteers and the derived values for nitrogen compared with values obtained by applying three currently used calibration methods to the same experimental data. The empirical equations relate TBN in normal people to age, height, weight and sex. The mean ratios of experimental to predicted TBN (with SEMs) are 1.013 +/- 0.017 and 1.002 +/- 0.014, respectively. Mean values of the ratio of TBN to fat-free mass (0.0340 +/- 0.0004) and of total body water to fat-free mass (0.716 +/- 0.002) agree closely with values reported elsewhere for normals by a variety of techniques including chemical analysis. Finally, TBN results based on the four different calibration methods are presented for five surgical patients, demonstrating the importance of the calibration method on estimates of TBN in patients with abnormal body composition. It is concluded that this technique will provide accurate estimates of the total body content of protein, water, and fat in intensive care patients

  16. Timing reference generators and chopper controllers for neutron sources

    International Nuclear Information System (INIS)

    Nelson, R.; Merl, R.; Rose, C.

    2001-01-01

    Due to AC-power-grid frequency fluctuations, the designers for accelerator-based spallation-neutron facilities have worked to optimize the competing and contrasting demands of accelerator and neutron chopper performance. Powerful new simulation techniques have enabled the modeling of the timing systems that integrate chopper controllers and chopper hardware. For the first time, we are able to quantitatively access the tradeoffs between these two constraints and design or upgrade a facility to optimize total system performance. Thus, at LANSCE, we now operate multiple chopper systems and the accelerator as simple slaves to a single master-timing-reference generator. For the SNS we recommend a similar system that is somewhat less tightly coupled to the power grid. (author)

  17. Activation analysis with neutron generators using short-lived radionuclides

    International Nuclear Information System (INIS)

    Salma, I.

    1993-01-01

    The short half-life involves a number of important differences in production, transportation and measurement of radionuclides, and in counting statistics as compared with those in traditional activation analysis. Experiments were performed to investigate the analytical possibilities and prospective utilization of short-lived radionuclides produced by 14-MeV neutron irradiation. A rapid pneumatic transfer system for use with neutron generators was installed and applied for detecting radionuclides with a half-life from 300 ms to 30 s. The transport time for samples with a total mass of 1-4 g is between 130 and 160 ms for pressurized air of 0.1-0.4 MPa. 11 elements were studied by the conventional activation method using both a typical pneumatic transport system (run time 3 s) and the fast pneumatic transport facility. The effect of the cyclic activation technique on the elemental sensitivities was also investigated. (orig.)

  18. Point-by-point model description of average prompt neutron data as a function of total kinetic energy of fission fragments

    International Nuclear Information System (INIS)

    Tudora, A.

    2013-01-01

    The experimental data of average prompt neutron multiplicity as a function of total kinetic energy of fragments <ν>(TKE) exhibit, especially in the case of 252 Cf(SF), different slopes dTKE/dν and different behaviours at low TKE values. The Point-by-Point (PbP) model can describe these different behaviours. The higher slope dTKE/dν and the flattening of <ν> at low TKE exhibited by a part of experimental data sets is very well reproduced when the PbP multi-parametric matrix ν(A,TKE) is averaged over a double distribution Y(A,TKE). The lower slope and the almost linear behaviour over the entire TKE range exhibited by other data sets is well described when the same matrix ν(A,TKE) is averaged over a single distribution Y(A). In the case of average prompt neutron energy in SCM as a function of TKE, different dTKE/dε slopes are also obtained by averaging the same PbP matrix ε(A,TKE) over Y(A,TKE) and over Y(A). The results are exemplified for 3 fissioning systems benefiting of experimental data as a function of TKE: 252 Cf(SF), 235 U(n th ,f) and 239 Pu(n th ,f). In the case of 234 U(n,f) for the first time it was possible to calculate <ν>(TKE) and <ε>(TKE) at many incident energies by averaging the PbP multi-parametric matrices over the experimental Y(A,TKE) distributions recently measured at IRMM for 14 incident energies in the range 0.3- 5 MeV. The results revealed that the slope dTKE/dν does not vary with the incident energy and the flattening of <ν> at low TKE values is more pronounced at low incident energies. The average model parameters dependences on TKE resulted from the PbP treatment allow the use of the most probable fragmentation approach, having the great advantage to provide results at many TKE values in a very short computing time compared to PbP and Monte Carlo treatments. (author)

  19. A simple method for correcting the neutron self-shielding effect of matrix and improving the analytical response in prompt gamma-ray neutron activation analysis

    International Nuclear Information System (INIS)

    Sudarshan, K.; Tripathi, R.; Nair, A.G.C.; Acharya, R.; Reddy, A.V.R.; Goswami, A.

    2005-01-01

    A simple method using an internal standard is proposed to correct for the self-shielding effect of B, Cd and Gd in a matrix. This would increase the linear dynamic range of PGNAA in analyzing samples containing these elements. The method is validated by analyzing synthetic samples containing large amounts of B, Cd, Hg and Gd, the elements having high neutron absorption cross-section, in aqueous solutions and solid forms. A simple Monte-Carlo simulation to find the extent of self-shielding in the matrix is presented. The method is applied to the analysis of titanium boride alloy containing large amount of boron. The satisfactory results obtained showed the efficacy of the method of correcting for the self-shielding effects in the sample

  20. Monte Carlo efficiency calibration of a neutron generator-based total-body irradiator

    International Nuclear Information System (INIS)

    Shypailo, R.J.; Ellis, K.J.

    2009-01-01

    Many body composition measurement systems are calibrated against a single-sized reference phantom. Prompt-gamma neutron activation (PGNA) provides the only direct measure of total body nitrogen (TBN), an index of the body's lean tissue mass. In PGNA systems, body size influences neutron flux attenuation, induced gamma signal distribution, and counting efficiency. Thus, calibration based on a single-sized phantom could result in inaccurate TBN values. We used Monte Carlo simulations (MCNP-5; Los Alamos National Laboratory) in order to map a system's response to the range of body weights (65-160 kg) and body fat distributions (25-60%) in obese humans. Calibration curves were constructed to derive body-size correction factors relative to a standard reference phantom, providing customized adjustments to account for differences in body habitus of obese adults. The use of MCNP-generated calibration curves should allow for a better estimate of the true changes in lean tissue mass that many occur during intervention programs focused only on weight loss. (author)

  1. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, P., E-mail: peter.andersson@physics.uu.se; Andersson-Sunden, E.; Sjöstrand, H.; Jacobsson-Svärd, S. [Department of Physics and Astronomy, Division of Applied Nuclear Physics, Uppsala University, Lägerhyddsgatan 1, 751 20 Uppsala (Sweden)

    2014-08-01

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm{sup −1}, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

  2. Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator.

    Science.gov (United States)

    Andersson, P; Andersson-Sunden, E; Sjöstrand, H; Jacobsson-Svärd, S

    2014-08-01

    In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful

  3. Materials-based process tolerances for neutron generator encapsulation

    International Nuclear Information System (INIS)

    Berry, Ryan S.; Adolf, Douglas Brian; Stavig, Mark Edwin

    2007-01-01

    Variations in the neutron generator encapsulation process can affect functionality. However, instead of following the historical path in which the effects of process variations are assessed directly through functional tests, this study examines how material properties key to generator functionality correlate with process variations. The results of this type of investigation will be applicable to all generators and can provide insight on the most profitable paths to process and material improvements. Surprisingly, the results at this point imply that the process is quite robust, and many of the current process tolerances are perhaps overly restrictive. The good news lies in the fact that our current process ensures reproducible material properties. The bad new lies in the fact that it would be difficult to solve functional problems by changes in the process

  4. Materials-based process tolerances for neutron generator encapsulation.

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Ryan S.; Adolf, Douglas Brian; Stavig, Mark Edwin

    2007-10-01

    Variations in the neutron generator encapsulation process can affect functionality. However, instead of following the historical path in which the effects of process variations are assessed directly through functional tests, this study examines how material properties key to generator functionality correlate with process variations. The results of this type of investigation will be applicable to all generators and can provide insight on the most profitable paths to process and material improvements. Surprisingly, the results at this point imply that the process is quite robust, and many of the current process tolerances are perhaps overly restrictive. The good news lies in the fact that our current process ensures reproducible material properties. The bad new lies in the fact that it would be difficult to solve functional problems by changes in the process.

  5. Proposal for an accelerator-based neutron generator

    International Nuclear Information System (INIS)

    Grand, P.

    1975-07-01

    An Accelerator-based Neutron Generator is described that consists of a 30-MeV deuteron linear accelerator using a flowing liquid lithium target. With a continuous deuteron current of 100 milliamperes, a source intensity of more than 10 16 neutrons per second will be produced. The neutrons will be emitted in a roughly collimated beam. The proposed facility can be divided into two areas: the 30-MeV linear accelerator and the multiple-target experimental area. The 30-MeV accelerator will consist of eight rf accelerating cavities in a single vacuum tank, each cavity being powered by its own rf power amplifier operating at 50 MHz. To shield the beam bunches from the rf field when it is in the decelerating direction, 66 ''drift tubes'' will be included; the drift-tube structures will include quadrupole magnets which will keep the beam focused. The accelerator will produce a continuous beam of 100 milliamperes. Beam power will thus be 3.0 megawatts; total power including rf losses in the accelerating cavities will be 4.5 megawatts. The injectors for the linear accelerator will be two 500-kV dc accelerators, one for injection of D + ions and the other for D - ions. They can be used simultaneously or one can serve as a spare in case of breakdown or maintenance of the other. (U.S.)

  6. Mercury and gold concentrations of highly polluted environmental samples determined using prompt gamma-ray analysis and instrument neutron activation analysis

    Science.gov (United States)

    Osawa, Takahito; Hatsukawa, Yuichi; Appel, Peter W. U.; Matsue, Hideaki

    2011-04-01

    The authors have established a method of determining mercury and gold in severely polluted environmental samples using prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA). Since large amounts of mercury are constantly being released into the environment by small-scale gold mining in many developing countries, the mercury concentration in tailings and water has to be determined to mitigate environmental pollution. Cold-vapor atomic absorption analysis, the most pervasive method of mercury analysis, is not suitable because tailings and water around mining facilities have extremely high mercury concentrations. On the other hand, PGA can determine high mercury concentrations in polluted samples as it has an appropriate level of sensitivity. Moreover, gold concentrations can be determined sequentially by using INAA after PGA. In conclusion, the analytical procedure established in this work using PGA and INAA is the best way to evaluate the degree of pollution and the tailing resource value. This method will significantly contribute to mitigating problems in the global environment.

  7. Mercury and gold concentrations of highly polluted environmental samples determined using prompt gamma-ray analysis and instrument neutron activation analysis

    International Nuclear Information System (INIS)

    Osawa, Takahito; Hatsukawa, Yuichi; Appel, Peter W.U.; Matsue, Hideaki

    2011-01-01

    The authors have established a method of determining mercury and gold in severely polluted environmental samples using prompt gamma-ray analysis (PGA) and instrumental neutron activation analysis (INAA). Since large amounts of mercury are constantly being released into the environment by small-scale gold mining in many developing countries, the mercury concentration in tailings and water has to be determined to mitigate environmental pollution. Cold-vapor atomic absorption analysis, the most pervasive method of mercury analysis, is not suitable because tailings and water around mining facilities have extremely high mercury concentrations. On the other hand, PGA can determine high mercury concentrations in polluted samples as it has an appropriate level of sensitivity. Moreover, gold concentrations can be determined sequentially by using INAA after PGA. In conclusion, the analytical procedure established in this work using PGA and INAA is the best way to evaluate the degree of pollution and the tailing resource value. This method will significantly contribute to mitigating problems in the global environment.

  8. Metal impurities profile in a 450kg multi-crystalline silicon ingot by Cold Neutron Prompt Gamma-ray Activation Analysis

    International Nuclear Information System (INIS)

    Baek, Hani; Sun, Gwang Min; Kim, Ji seok; Oh, Mok; Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Baek, Sung Yeol; Tuan, Hoang Sy Minh

    2014-01-01

    Metal impurities are harmful to multi-crystalline silicon solar cells. They reduce solar cell conversion efficiencies through increased carrier recombination. They are present as isolated point-like impurities or precipitates. This work is to study the concentration profiles of some metal impurities of the directionally solidified 450kg multi-crystalline silicon ingot grown for solar cell production. The concentration of such impurities are generally below 10 15 cm -3 , and as such cannot be detected by physical techniques such as secondary-ion-mass spectroscopy(SIMS). So, we have tried to apply Cold Neutron - Prompt Gamma ray Activation Analysis(CN-PGAA) at the HANARO reactor research. The impurity concentrations of Au, Mn, Pt, Mo of a photovoltaic grade multi-crystalline silicon ingot appear by segregation from the liquid to the solid phase in the central region of the ingot during the crystallization. In the impurities concentration of the bottom region is higher than middle region due to the solid state diffusion. Towards the top region the segregation impurities diffused, during cooling process

  9. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    International Nuclear Information System (INIS)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric; Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt; Audouin, Laurent; Tassan-Got, Laurent; Aumann, Thomas; Casarejos, Enrique; Farget, Fanny; Rodriguez-Tajes, Carme; Heinz, Andreas; Jurado, Beatriz; Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut

    2015-01-01

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  10. Studies on fission with ALADIN. Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Julie-Fiona; Taieb, Julien; Chatillon, Audrey; Belier, Gilbert; Boutoux, Guillaume; Ebran, Adeline; Gorbinet, Thomas; Grente, Lucie; Laurent, Benoit; Pellereau, Eric [CEA DAM Bruyeres-le-Chatel, Arpajon (France); Alvarez-Pol, Hector; Ayyad, Yassid; Benlliure, Jose; Cortina Gil, Dolores; Caamano, Manuel; Fernandez Dominguez, Beatriz; Paradela, Carlos; Ramos, Diego; Rodriguez-Sanchez, Jose-Luis; Vargas, Jossitt [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Audouin, Laurent; Tassan-Got, Laurent [CNRS/IN2P3, IPNO, Orsay (France); Aumann, Thomas [Technische Universitaet Darmstadt, Darmstadt (Germany); Casarejos, Enrique [Universidad de Vigo, Vigo (Spain); Farget, Fanny; Rodriguez-Tajes, Carme [CNRS/IN2P3, GANIL, Caen (France); Heinz, Andreas [Chalmers University of Technology, Gothenburg (Sweden); Jurado, Beatriz [CNRS/IN2P3, CENBG, Gradignan (France); Kelic-Heil, Aleksandra; Kurz, Nikolaus; Nociforo, Chiara; Pietri, Stephane; Rossi, Dominic; Schmidt, Karl-Heinz; Simon, Haik; Voss, Bernd; Weick, Helmut [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2015-12-15

    A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism. (orig.)

  11. A test-type hyper-thermal neutron generator for neutron capture therapy - estimation of neutron energy spectrum by simulation calculations and TOF experiments

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Tooru; Kobayashi, Katsuhei

    1999-01-01

    In order to clarify the irradiation characteristics of hyper-thermal neutrons and the feasibility of a hyper-thermal neutron irradiation field for neutron capture therapy, a 'test-type' hyper-thermal neutron generator was designed and made. Graphite of 6 cm thickness and 21 cm diameter was selected as the high temperature scatterer. The scatterer is heated up to 1200 deg. C maximum using molybdenum heaters. The radiation heat is shielded by reflectors of molybdenum and stainless steel. The temperature is measured using three R-type thermo-couples and controlled by a program controller. The total thickness of the generator is designed to be as thin as possible, 20 cm in maximum, in the standing point of the neutron beam intensity. The thermal stability, controllability and safety of the generator at high temperature employment were confirmed by the heating tests. As one of the experiments for the characteristics estimation, the neutron energy spectrum dependent on the scatterer temperature was measured by the TOF (time of flight) method using the LINAC neutron generator. The estimations by simulation calculations were also performed. From the experiment and calculation results, it was confirmed that the neutron temperature shifted higher as the scatterer temperature was higher. The prospect of the feasibility of the 'hyper-thermal neutron irradiation field for NCT' was opened from the estimation results of the generator characteristics by the simulation calculations and experiments

  12. Monte Carlo Simulation on Compensated Neutron Porosity Logging in LWD With D-T Pulsed Neutron Generator

    International Nuclear Information System (INIS)

    Zhang Feng; Hou Shuang; Jin Xiuyun

    2010-01-01

    The process of neutron interaction induced by D-T pulsed neutron generator and 241 Am-Be source was simulated by using Monte Carlo method. It is concluded that the thermal neutron count descend exponentially as the spacing increasing. The smaller porosity was, the smaller the differences between the two sources were. When the porosity reached 40%, the ratio of thermal neutron count generated by D-T pulsed neutron source was much larger than that generated by 241 Am-Be neutron source, and its distribution range was wider. The near spacing selected was 20-30 cm, and that of far spacing was about 60-70 cm. The detection depth by using D-T pulsed neutron source was almost unchanged under condition of the same sapcing, and the sensitivity of measurement to the formation porosity decreases. The results showed that it can not only guarantee the statistic of count, but also improve detection sensitivity and depth at the same time of increasing spacing. Therefore, 241 Am-Be neutron source can be replaced by D-T neutron tube in LWD tool. (authors)

  13. Trial production of hyper-thermal neutron generator for Neutron Capture Therapy (NCT) and its radiation properties

    International Nuclear Information System (INIS)

    Sakurai, Yoshinori; Kobayashi, Toru

    1999-01-01

    In NCT, it was at first important to give a cancer portion to radiation dose required for its recovery. By finding out that whole cross-section of water comprising of a living body decreased monotonously with increase of neutron energy from about 100 barn against thermal neutron, became about 40 barn at about 0.5 eV and kept constant to 40 barn till at about 100 eV, application of thermal neutron shifted to higher temperature side, called Hyper thermal neutron, to NCT is proposed. The Hyper thermal neutron radiation can be expected to have similar controllability to that of the thermal neutron radiation. In 1977 fiscal year, a trial Hyper thermal neutron generator was produced on a base of up-to-date investigation results. As a part of property evaluation of the generator, evaluation of energy spectra in the Hyper thermal neutron generated at LINAC by TOF was conducted to confirm shift of the spectra to high temperature side. And, a Fantom experiment at KUR heavy water neutron radiation facility was also conducted to confirm effect of improvement in deep portion dose distribution. (G.K.)

  14. Feasibility study of application of Prompt Gamma Neutron Activation Analysis (PGNAA) method in TRIGA IPR-R1 reactor; Estudo da viabilidade de aplicação do método Prompt Gamma Neutron Activation Analysis (PGNAA) no reator TRIGA IPR-R1

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Bruno Teixeira

    2016-07-01

    The TRIGA Mark I IPR-R1 research reactor is located at Nuclear Technology Development Centre (CDTN), Brazilian Commission for Nuclear Energy (CNEN), in Belo Horizonte, Brazil. The reactor operates at 100 kW but the core configuration allows the increasing of the power up to 250 kW. It has been applied research, training and radioisotopes production. The establishment of the Prompt Gamma Neutron Activation Analysis (PGNAA) method at the TRIGA IPR-R1 reactor will significantly increase the types of matrices analysed as well as the number of chemical elements. Additionally it will complement the neutron activation analysis. This work presents a proposed design of a PGNAA facility to be installed at the TRIGA IPR-R1. The proposed design is based on a tube as a neutron guide from the reactor core, inside the reactor pool, 6 m below the room’s level where shall be located the rack containing the set sample/detector/shielding. Thus, the aim of this study is to verify the feasibility to establish the PGNAA method in IPR-R1 through theoretical study applying the Monte Carlo code. The feasibility of establishing the PGAA method at the IPR-R1 installations was evaluated through of the calculations of neutron flux, radioactive capture reaction rates and detection limits for some isotopes. According to the obtained results, it can be concluded that is possible to establish the PGAA method at the IPR-R1 reactor, even with some restrictions in its theoretical design calculated by MCNP. (author)

  15. Neutron source investigations in support of the cross section program at the Argonne Fast-Neutron Generator

    International Nuclear Information System (INIS)

    Meadows, J.W.; Smith, D.L.

    1980-05-01

    Experimental methods related to the production of neutrons for cross section studies at the Argonne Fast-Neutron Generator are reviewed. Target assemblies commonly employed in these measurements are described, and some of the relevant physical properties of the neutron source reactions are discussed. Various measurements have been performed to ascertain knowledge about these source reaction that is required for cross section data analysis purposes. Some results from these studies are presented, and a few specific examples of neutron-source-related corrections to cross section data are provided. 16 figures, 3 tables

  16. First PGAA and NAA experimental results from a compact high intensity D-D neutron generator

    International Nuclear Information System (INIS)

    Reijonen, J.; Leung, K.-N.; Firestone, R.B.; English, J.A.; Perry, D.L.; Smith, A.; Gicquel, F.; Sun, M.; Bandong, B.; Garabedian, G.; Revay, Zs.; Szentmiklosi, L.; Molnar, G.

    2003-01-01

    Various types of neutron generator systems have been designed and tested at the Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory. These generators are based on a D-D fusion reaction. These high power D-D neutron generators can provide neutron fluxes in excess of the current state of the art D-T neutron generators, without the use of pre-loaded targets or radioactive tritium gas. Safe and reliable long-life operations are the typical features of these D-D generators. All of the neutron generators developed in the Plasma and Ion Source Technology Group are utilizing powerful RF-induction discharge to generate the deuterium plasma. One of the advantages of using the RF-induction discharge is it's ability to generate high fraction of atomic ions from molecular gases, and the ability to generate high plasma densities for high extractable ion current from relatively small discharge volume

  17. Compact D-D/D-T neutron generators and their applications

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Tak Pui [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    Neutron generators based on the 2H(d,n)3He and 3H(d,n)4He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >109 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 1014 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 105 n/cm2s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and

  18. Compact D-D/D-T neutron generators and their applications

    International Nuclear Information System (INIS)

    Lou, Tak Pui

    2003-01-01

    Neutron generators based on the 2 H(d,n) 3 He and 3 H(d,n) 4 He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >10 9 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 10 14 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 10 5 n/cm 2 s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and Boron Neutron Capture Therapy (BNCT). The neutron flux required for positron

  19. Performance of a tagged neutron inspection system (TNIS) based on portable sealed generators

    International Nuclear Information System (INIS)

    Nebbia, G.; Pesente, S.; Lunardon, M.; Viesti, G.; LeTourneur, P.; Heuveline, F.; Mangeard, M.; Tcheng, C.

    2004-01-01

    A portable sealed neutron generator has been modified to produce 14MeV tagged neutron beams with an embedded YAP:Ce scintillation detector. The system has been tested by detecting the coincident gamma-rays produced in the irradiation of a graphite sample by means of a standard NaI(Tl) scintillator. Time resolution of about δt=4-5ns (FWHM) has been measured. The sealed neutron tube has been operated up to 10 7 neutron/s. Possible applications in non-destructive assays and future developments of the Tagged Neutron Inspection System concept are discussed

  20. The space distribution of neutrons generated in massive lead target by relativistic nuclear beam

    International Nuclear Information System (INIS)

    Chultem, D.; Damdinsuren, Ts.; Enkh-Gin, L.; Lomova, L.; Perelygin, V.; Tolstov, K.

    1993-01-01

    The present paper is devoted to implementation of solid state nuclear track detectors in the research of the neutron generation in extended lead spallation target. Measured neutrons space distribution inside the lead target and neutron distribution in the thick water moderator are assessed. (Author)

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

    International Nuclear Information System (INIS)

    Ledo Pereda, Luis Miguel; Vergara Limon, Sergio; Arteche Diaz, Raul

    2009-01-01

    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

  2. Neutron generators with size scalability, ease of fabrication and multiple ion source functionalities

    Science.gov (United States)

    Elizondo-Decanini, Juan M

    2014-11-18

    A neutron generator is provided with a flat, rectilinear geometry and surface mounted metallizations. This construction provides scalability and ease of fabrication, and permits multiple ion source functionalities.

  3. Generation of neutron scattering cross sections for silicon dioxide

    International Nuclear Information System (INIS)

    Ramos, R; Marquez Damian, J.I; Granada, J.R.; Cantargi, F

    2009-01-01

    A set of neutron scattering cross sections for silicon and oxygen bound in silicon dioxide were generated and validated. The cross sections were generated in the ACE format for MCNP using the nuclear data processing system NJOY, and the validation was done with published experimental data. This cross section library was applied to the calculation of five critical configurations published in the benchmark Critical Experiments with Heterogeneous Compositions of Highly Enriched Uranium, Silicon Dioxide and Polyethylene. The original calculations did not use the thermal scattering libraries generated in this work and presented significant differences with the experimental results. For this reason, the newly generated library was added to the input and the multiplication factor for each configuration was recomputed. The utilization of the thermal scattering libraries did not result in an improvement of the computational results. Based on this we conclude that integral experiments to validate this type of thermal cross sections need to be designed with a higher influence of thermal scattering in the measured result, and the experiments have to be performed under more controlled conditions. [es

  4. Fusion neutron generation by high-repetitive target injection

    International Nuclear Information System (INIS)

    Kitagawa, Yoneyoshi

    2015-01-01

    Pellet injection and repetitive laser illumination are key technologies for realizing inertial fusion energy. The Graduate School for the Creation of New Photonics Industries, Hamamatsu Photonics K. K. and Toyota Motor Corporation demonstrate the pellet injection, counter laser beams' engagement and neutron generation. Deuterated polystyrene (CD) bead pellets, after free-falling for a distance of 18 cm at 1 Hz, are successfully engaged by two counter laser beams from a diode-pumped, ultra-intense laser HAMA. The laser energy, pulse duration, wavelength and the intensity are 0.63 J per beam, 104 fs, 811 nm and 4.7 x 10 18 W/cm 2 , respectively. The irradiated pellets produce D (D, n) 3 He-reacted neutrons with a maximum yield of 9.5 x 10 4 /4π sr/shot. A straight channel with 10 μm-diameter is found through the beads. The pellet size is 1 mm. The results indicate potentially useful technologies for the next step in realizing inertial fusion energy. The results are reviewed as well as some oversea activities. (author)

  5. Tritium contamination and monitoring at Frascati Neutron Generator

    Energy Technology Data Exchange (ETDEWEB)

    Lucci, F.; Sandri, S.; Ianni, A. [ENEA, Frascati (Italy). Dipartimento Ambiente; Vasselli, R. [ANPA, Roma (Italy); Pillon, M.; Bettinali, L. [ENEA, Frascati (Italy). Dipartimento Energia

    1994-11-01

    The Frascati Neutron Generator (FGN) is a specialised 300 keV, 3 mA direct electrostatic deuteron accelerator which produces about 5-10{sup 1}1 14 MeV neutrons per second by D-T reactions on a tritium-titanium fixed target. This paper concerns the tritium contamination control and monitoring aspects after some months of testing and a preliminary period of operation of the plant. The tritium monitoring system is composed of both on-line and off-line devices to control the tritium concentration in the atmosphere measured from different parts of the plant: vacuum exhaust clean up (VECU) system, stack, etc. The on-line devices are three flux monitors, that sample continuosly the air from up to eight different points in the plant. The passive sampling system is designed to select the chemical form of tritium and to collect respectively HTO and HT in two different cartridges filled with an appropriate drying material. The response of the on-line tritium monitor system are exposed and discussed: some measurements performed with atmosphere dehumidifying apparatus of this system are described and the relevant results are analysed.

  6. Tritium contamination and monitoring at Frascati Neutron Generator

    International Nuclear Information System (INIS)

    Lucci, F.; Sandri, S.; Ianni, A.; Pillon, M.; Bettinali, L.

    1994-11-01

    The Frascati Neutron Generator (FGN) is a specialised 300 keV, 3 mA direct electrostatic deuteron accelerator which produces about 5-10 1 1 14 MeV neutrons per second by D-T reactions on a tritium-titanium fixed target. This paper concerns the tritium contamination control and monitoring aspects after some months of testing and a preliminary period of operation of the plant. The tritium monitoring system is composed of both on-line and off-line devices to control the tritium concentration in the atmosphere measured from different parts of the plant: vacuum exhaust clean up (VECU) system, stack, etc. The on-line devices are three flux monitors, that sample continuosly the air from up to eight different points in the plant. The passive sampling system is designed to select the chemical form of tritium and to collect respectively HTO and HT in two different cartridges filled with an appropriate drying material. The response of the on-line tritium monitor system are exposed and discussed: some measurements performed with atmosphere dehumidifying apparatus of this system are described and the relevant results are analysed

  7. Calculating the energy spectrum of neutrons from tritium target of the NG-150 type generator

    International Nuclear Information System (INIS)

    Bortash, A.I.; Kuznetsov, V.S.

    1987-01-01

    Calculation procedure of neutron spectra yielding from the NG-150 generator target chamber with regard to deutron moderation is suggested. Using the suggested procedure, neutron spectra for different escape angles formed in the tritium target are calculated. The spectrum of neutrons scattered in cooling water is calculated. The mean energy of neutrons escaping at the angle of 0 deg equalling 14.5 MeV is obtained

  8. Design of auto-control high-voltage control system of pulsed neutron generator

    International Nuclear Information System (INIS)

    Lv Juntao

    2008-01-01

    It is difficult to produce multiple anode controlling time sequences under different logging mode for the high-voltage control system of the conventional pulsed neutron generator. It is also difficult realize sequential control among anode high-voltage, filament power supply and target voltage to make neutron yield stable. To these problems, an auto-control high-voltage system of neutron pulsed generator was designed. It not only can achieve anode high-voltage double blast time sequences, which can measure multiple neutron blast time sequences such as Σ, activated spectrum, etc. under inelastic scattering mode, but also can realize neutron generator real-time measurement of multi-state parameters and auto-control such as target voltage pulse width modulation (PWM), filament current, anode current, etc., there by it can produce stable neutron yield and realize stable and accurate measurement of the pulsed neutron full spectral loging tool. (authors)

  9. Calibration Of A 14 MeV Neutron Generator With Reference To NBS-1

    International Nuclear Information System (INIS)

    Heimbach, Craig R.

    2011-01-01

    NBS-1 is the US national neutron reference source. It has a neutron emission rate (June 1961) of 1.257x10 6 n/s 1,2,3 with an uncertainty of 0.85%(k = 1). Neutron emission-rate calibrations performed at the National Institute of Standards and Technology (NIST) are made in comparison to this source, either directly or indirectly. To calibrate a commercial 14 MeV neutron generator, NIST performed a set of comparison measurements to evaluate the neutron output relative to NBS-1. The neutron output of the generator was determined with an uncertainty of about 7%(k = 1). The 15-hour half-life of one of the reactions used also makes possible off-site measurements. Consideration is given to similar calibrations for a 2.5 MeV neutron generator.

  10. CIAE 600 kV ns pulse neutron generator

    International Nuclear Information System (INIS)

    Shen Guanren; Guan Xialing; Chen Hongtao

    2001-01-01

    The overall composition of CIAE 600 kV ns Pulse Neutron Generator (CPNG) are introduced, and its characteristic, main technological performance and application were also given. CPNG consists of high voltage power supply with highest output voltage 600 kV, direct current 15 mA, stability and ripple ≤0.1%, 2214 mm x 1604 mm x 1504 mm stainless steel high voltage electrode, built in head equipment uniform field accelerating tube, ns pulsed installation, turbomolecular vacuum pump system and drift pipes at 0 degree and 45 degree. Its characteristics are: (1) high current beam; (2) high current beam ns pulsed installation made use of low energy for chopper and high energy for buncher; (3) compactly laid out and simple in structure

  11. The AECL study for an intense neutron - generator (technical details)

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G A; Tunnicliffe, P R

    1966-07-01

    The AECL study for an intense neutron-generator has been in progress for two years. Recently the scientific and technical details and the conceptual designs were compiled in a report supporting proposals addressed to AECL's Board of Directors for further work. The compilation is being issued in this form to permit further discussion of the technical aspects. However readers are asked to appreciate that it was written primarily for an AECL audience, and specifically that those chapters giving tentative information about costs, the rate of investment and similar items have been omitted or modified, many references have been made to interim internal reports in order to complete the local documentation, but these references do not imply that the reports themselves can be made generally available. (author)

  12. The AECL study for an intense neutron - generator (technical details)

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, G.A.; Tunnicliffe, P.R

    1966-07-01

    The AECL study for an intense neutron-generator has been in progress for two years. Recently the scientific and technical details and the conceptual designs were compiled in a report supporting proposals addressed to AECL's Board of Directors for further work. The compilation is being issued in this form to permit further discussion of the technical aspects. However readers are asked to appreciate that it was written primarily for an AECL audience, and specifically that those chapters giving tentative information about costs, the rate of investment and similar items have been omitted or modified, many references have been made to interim internal reports in order to complete the local documentation, but these references do not imply that the reports themselves can be made generally available. (author)

  13. The AECL study for an intense neutron - generator (technical details)

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Tunnicliffe, P.R.

    1966-01-01

    The AECL study for an intense neutron-generator has been in progress for two years. Recently the scientific and technical details and the conceptual designs were compiled in a report supporting proposals addressed to AECL's Board of Directors for further work. The compilation is being issued in this form to permit further discussion of the technical aspects. However readers are asked to appreciate that it was written primarily for an AECL audience, and specifically that those chapters giving tentative information about costs, the rate of investment and similar items have been omitted or modified, many references have been made to interim internal reports in order to complete the local documentation, but these references do not imply that the reports themselves can be made generally available. (author)

  14. Determination of the emission rate for the 14 MeV neutron generator with the use of radio-yttrium

    OpenAIRE

    Laszynska Ewa; Jednorog Slawomir; Ziolkowski Adam; Gierlik Michal; Rzadkiewicz Jacek

    2015-01-01

    The neutron emission rate is a crucial parameter for most of the radiation sources that emit neutrons. In the case of large fusion devices the determination of this parameter is necessary for a proper assessment of the power release and the prediction for the neutron budget. The 14 MeV neutron generator will be used for calibration of neutron diagnostics at JET and ITER facilities. The stability of the neutron generator working parameters like emission and angular homogeneity affects the accu...

  15. Analysis of the Neutron Generator and Target for the LSDTS System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Je; Lee, Yong Deok; Song, Jae Hoon; Song, Kee Chan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-11-15

    A preliminary analysis was performed based on the literatures and the patents for the neutron generators and targets for the lead slowing down time spectrometer (LSDTS) system. It was found that local neutron generator did not exhibit enough neutron intensity such as 1E+12 n/s, which is a minimum requirement for the LSDTS system to overcome curium backgrounds. However, a neutron generator implemented with an electron accelerator may provide a higher intensity around 1E+13 n/s and it is required to investigate further including a detail analysis. In addition to the neutron generator, a study on target was performed with the Monte Carlo simulation. In the study, an optimal design of target was suggested to provide a high neutron yield and a better thermal resistance. The suggested target consists several cylindrical plates with a certain cooling gap, which have increasing thickness and increasing radius.

  16. A neutron monitor for D-T neutron generator in the PGNAA-based online measurement system

    Science.gov (United States)

    Shan, Qing; Shengnan, Chu; Yongsheng, Ling; Pingkun, Cai; Wenbao, Jia

    2017-06-01

    A new type of neutron detector, which consists of polyethylene, an EJ200 plastic scintillator and fused silica, was proposed and optimized by the GEANT4 Monte Carlo simulation toolkit in our previous studies. The calculation method was also described for calculating the neutron flux in the preset condition. This paper reports the manufacturing of the prototype detector. Experiments are conducted to validate the feasibility of this detector. A D-T neutron generator and a 60Co gamma-ray source are used in the experiments. The designed detector and a He-3 proportional counter are simultaneously used to monitor the yield of the D-T neutron generator. A more universal calculation method is developed to enable the application of this detector to common conditions. The experimental results show that the performance of the designed detector is comparable to that of the He-3 proportional counter. The relative deviations between their normalized counts are less than 5%.

  17. A High Intensity Multi-Purpose D-D Neutron Generator for Nuclear Engineering Laboratories

    International Nuclear Information System (INIS)

    Ka-Ngo Leung; Jasmina L. Vujic; Edward C. Morse; Per F. Peterson

    2005-01-01

    This NEER project involves the design, construction and testing of a low-cost high intensity D-D neutron generator for teaching nuclear engineering students in a laboratory environment without radioisotopes or a nuclear reactor. The neutron generator was designed, fabricated and tested at Lawrence Berkeley National Laboratory (LBNL)

  18. Survey of neutron spectra generated by the fission of heavy nuclei induced by fast neutrons

    International Nuclear Information System (INIS)

    Lovchikova, G.N.; Trufanov, A.M.

    1997-01-01

    A review of neutron fission spectra measurements is presented. This review and the results of this analysis was performed with the participation of the authors. It is shown that there is a need for additional measurements of the energy and angular distributions of secondary neutrons in order to improve the understanding of the neutron emission mechanism in fission. (author). 21 refs, 6 figs

  19. Next generation neutron scattering at Neutron Science Center project in JAERI

    International Nuclear Information System (INIS)

    Yamada, Yasusada; Watanabe, Noboru; Niimura, Nobuo; Morii, Yukio; Katano, Susumu; Aizawa, Kazuya; Suzuki, Jun-ichi; Koizumi, Satoshi; Osakabe, Toyotaka.

    1997-01-01

    Japan Atomic Energy Research Institute (JAERI) has promoted neutron scattering researches by means of research reactors in Tokai Research Establishment, and proposes 'Neutron Science Research Center' to develop the future prospect of the Tokai Research Establishment. The scientific fields which will be expected to progress by the neutron scattering experiments carried out at the proposed facility in the Center are surveyed. (author)

  20. Results and plans on the development of a pulsed neutron generator

    International Nuclear Information System (INIS)

    Sztaricskai, T.; Vasvary, L.; Petoe, G.

    1976-01-01

    Using the vacuum system of an old van de Graaff machine a new pulsed neutron generator has been developed. The block diagram, the scheme of generators arrangement and the electrode system of the ion bunching parts are shown

  1. Feasibility study on medical isotope production using a compact neutron generator.

    Science.gov (United States)

    Leung, Ka-Ngo; Leung, James K; Melville, Graeme

    2018-07-01

    Compact neutron generators can provide high flux of neutrons with energies ranging from thermal (0.025 eV) to 14 MeV. Recent measurements demonstrated high neutron yields from the D- 7 Li fusion reaction at an interaction energy of 500 keV. Using the D- 7 Li reaction and applying new advancements in high flux neutron generator technology along with the commercial availability of high voltage DC power supplies enables the production of useful quantities of radioisotopes for medical applications. Using the known neutron reaction cross-sections, it has been estimated that hundreds-to-thousands MBq (or tens-to-hundreds mCi) of 99 Mo, 225 Ac, 64 Cu and 67 Cu can be obtained from a compact high flux neutron generator. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Use of a high repetition rate neutron generator for in vivo body composition measurements via neutron inelastic scattering

    International Nuclear Information System (INIS)

    Kehayias, J.J.; Ellis, K.J.; Cohn, S.H.; Weinlein, J.H.

    1986-01-01

    A small D-T neutron generator with a high pulse rate is used for the in vivo measurement of body carbon, oxygen and hydrogen. The core of the neutron generator is a 13 cm-long Zetatron tube pulsed at a rate of 10 kHz delivering 10 3 to 10 4 neutrons per pulse. A target-current feedback system regulates the source of the accelerator to assure constant neutron output. Carbon is measured by detecting the 4.44 MeV γ-rays from inelastic scattering. The short half-life of the 4.44 MeV state of carbon requires detection of the γ-rays during the 10 μs neutron pulse. Generators with low pulsing rate were found inappropriate for carbon measurements because of their low duty-cycle (high neutron output during the pulse). In vivo measurements were performed with normal volunteers using a scanning bed facility for a dose less than 25 mrem. This technique offers medical as well as general bulk analysis applications. 8 refs., 5 figs

  3. Generation of neutron standing waves at total reflection of polarized neutrons

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Nikitenko, Yu.V.; Kozhevnikov, S.V.; Radu, F.; Kruijs, R.; Rekveldt, M.Th.

    1999-01-01

    The regime of neutron standing waves at reflection of polarized thermal neutrons from the structure glass/Cu (1000 A Angstrom)/Ti (2000 A Angstrom)/Co (60 A Angstrom)/Ti (300 A Angstrom) in a magnetic field directed at an angle to the sample plane is realized. The intensity of neutrons with a particular spin projection on the external magnetic field direction appears to be a periodic function of the neutron wavelength and the glancing angle of the reflected beam. It is shown that the neutron standing wave regime can be a very sensitive method for the determination of changes in the spatial position of magnetic noncollinear layers. (author)

  4. A D-D/D-T fusion reaction based neutron generator system for liver tumor BNCT

    International Nuclear Information System (INIS)

    Koivunoro, H.; Lou, T.P.; Leung, K. N.; Reijonen, J.

    2003-01-01

    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 10 B(n,α) 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

  5. IEC-based neutron generator for security inspection system

    International Nuclear Information System (INIS)

    Miley, G.H.; Wu, L.; Kim, H.J.

    2005-01-01

    Use of a combined X-ray and neutron source for security inspections based on Inertial Electrostatic Confinement (IEC) fusion is discussed. Current inspection systems typically use X-ray techniques, but thermal neutron analysis (TNA) and fast neutron analysis (FNA), allow expanded detection of certain types of explosives. The integrated unit proposed here uses three separate IEC sources producing 14 and 2.45 MeV neutrons plus soft X-rays. This combination allows multiple detection methods with the composite signal analysis being done by a fuzzy logic system, significantly reducing false signals. (author)

  6. NEUTRON GENERATOR FACILITY AT SFU: GEANT4 DOSE RATE PREDICTION AND VERIFICATION.

    Science.gov (United States)

    Williams, J; Chester, A; Domingo, T; Rizwan, U; Starosta, K; Voss, P

    2016-11-01

    Detailed dose rate maps for a neutron generator facility at Simon Fraser University were produced via the GEANT4 Monte Carlo framework. Predicted neutron dose rates throughout the facility were compared with radiation survey measurements made during the facility commissioning process. When accounting for thermal neutrons, the prediction and measurement agree within a factor of 2 or better in most survey locations, and within 10 % inside the vault housing the neutron generator. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Prompt γ energy spectrum by associated particle technique

    International Nuclear Information System (INIS)

    An Li; He Tie; Guo Haiping; Yang Jian; Zheng Pu; Wang Xinhua; Chen Yuan; Mou Yunfeng; Zhu Chuanxin; Yang Xiaofei

    2010-01-01

    The basic principle of associated alpha particle technique and the measurement system were introduced. The characteristic prompt gamma-rays coming from water, graphite, liquid nitrogen, ammonium nitrate, melamine and simulated samples induced by D-T neutron from generator were gained by single alpha particle detector and gamma-ray detector. The complex gamma-ray spectra were deconvolved. The element ratio between the experiment and chemic molecular formula is agreement in 10%. (authors)

  8. Report of the advisory group meeting on optimal use of accelerator-based neutron generators

    International Nuclear Information System (INIS)

    1998-01-01

    During the past 20 to 25 years, the IAEA has provided a number of laboratories in the developing member states with neutron generators. These neutron generators were originally supplied for the primary purpose of neutron activation analysis. In order to promote the optimal use of these machines, a meeting was held in 1996, resulting in a technical document manual for the upgrading and troubleshooting of neutron generators. The present meeting is a follow-up to that earlier meeting. There are several reasons why some neutron generators are not fully utilized. These include lack of infrastructure, such as an appropriate shielded building and loss of adequately trained technical and academic personnel. Much of the equipment is old and lacking spare parts, and in a few cases there is a critical lack of locally available knowledge and experience in accelerator technology. The report contains recommendations for dealing with these obstacles

  9. Heat generation and temperature-rise in ordinary concrete due to capture of thermal neutrons

    International Nuclear Information System (INIS)

    Abdo, E.A.; Amin, E.

    1997-01-01

    The aim of this work is the evaluation of the heat generation and temperature-rise in local ordinary concrete as a biological shield due to capture of total thermal and reactor thermal neutrons. The total thermal neutron fluxes were measured and calculated. The channel number 2 of the ETRR-1 reactor was used in the measurements as a neutron source. Computer code ANISN (VAX version) and neutron multigroup cross-section library EURLiB-4 was used in the calculations. The heat generation and temperature-rise in local ordinary concrete were evaluated and calculated. The results were displayed in curves to show the distribution of thermal neutron fluxes and heat generation as well as temperature-rise with the shield thickness. The results showed that, the heat generation as well as the temperature-rise have their maximum values in the first layers of the shield thickness. 4 figs., 12 refs

  10. Neutron generator production mission in a national laboratory.

    Energy Technology Data Exchange (ETDEWEB)

    Pope, Larry E.

    2007-08-01

    In the late 1980's the Department of Energy (DOE) faced a future budget shortfall. By the spring of 1991, the DOE had decided to manage this problem by closing three production plants and moving production capabilities to other existing DOE sites. As part of these closings, the mission assignment for fabrication of War Reserve (WR) neutron generators (NGs) was transferred from the Pinellas Plant (PP) in Florida to Sandia National Laboratories, New Mexico (SNL/NM). The DOE directive called for the last WR NG to be fabricated at the PP before the end of September 1994 and the first WR NG to be in bonded stores at SNL/NM by October 1999. Sandia National Laboratories successfully managed three significant changes to project scope and schedule and completed their portion of the Reconfiguration Project on time and within budget. The PP was closed in October 1995. War Reserve NGs produced at SNL/NM were in bonded stores by October 1999. The costs of the move were recovered in just less than five years of NG production at SNL/NM, and the annual savings today (in 1995 dollars) is $47 million.

  11. Descartes: a new generation system for neutronic calculations

    International Nuclear Information System (INIS)

    Calvin, Ch.

    2005-01-01

    Descartes is a common project between CEA, Framatome and EDF for the development of a new generation system for neutronic calculations. The main objectives which have leaded the design of the platform are the following: - flexible: from best-estimate calculations to industrial design; - open: easy coupling with other disciplines (thermo mechanics, thermal hydraulics); - enlarged scope: criticality, shielding, all types of reactors; - robust: well known behavior in its field of application; - safe: qualified and uncertainties assessment; and - User-friendly: user interface, databases; Descartes is based on the object oriented method using UML design and programmed in C++ and the Python interpreted script language. We will present in this paper the general architecture of the platform and the internal data model used which allows the definition of common exchange structures between solvers and the different modules which can be used either for lattice or core calculations. In a second time we will present a short description of the main solvers implemented within the Descartes platform. We will conclude with some first results of industrial PWR calculations. (author)

  12. FLaapLUC: A pipeline for the generation of prompt alerts on transient Fermi-LAT γ-ray sources

    Science.gov (United States)

    Lenain, J.-P.

    2018-01-01

    The large majority of high energy sources detected with Fermi-LAT are blazars, which are known to be very variable sources. High cadence long-term monitoring simultaneously at different wavelengths being prohibitive, the study of their transient activities can help shedding light on our understanding of these objects. The early detection of such potentially fast transient events is the key for triggering follow-up observations at other wavelengths. A Python tool, FLaapLUC, built on top of the Science Tools provided by the Fermi Science Support Center and the Fermi-LAT collaboration, has been developed using a simple aperture photometry approach. This tool can effectively detect relative flux variations in a set of predefined sources and alert potential users. Such alerts can then be used to trigger target of opportunity observations with other facilities. It is shown that FLaapLUC is an efficient tool to reveal transient events in Fermi-LAT data, providing quick results which can be used to promptly organise follow-up observations. Results from this simple aperture photometry method are also compared to full likelihood analyses. The FLaapLUC package is made available on GitHub and is open to contributions by the community.

  13. Calculation of the importance-weighted neutron generation time using MCNIC method

    International Nuclear Information System (INIS)

    Feghhi, S.A.H.; Shahriari, M.; Afarideh, H.

    2008-01-01

    In advanced nuclear power systems, such as ADS, the need for reliable kinetics parameters is of considerable importance because of the lower value for β eff due to the large amount of transuranic elements loaded in the core of those systems. All reactor kinetic parameters are weighted quantities. In other words each neutron with a given position and energy is weighted with its importance. Neutron generation time as an important kinetic parameter, in all nuclear power systems has a significant role in the analysis of fast transients. The difference between non-weighted neutron generation time; Λ; standard in most Monte Carlo codes; and the weighted one Λ + can be quite significant depending on the type of the system. In previous work, based on the physical concept of neutron importance, a new method; MCNIC; using the MCNP code has been introduced for the calculation of neutron importance in fissionable assemblies for all criticality states. In the present work the applicability of MCNIC method has been extended for the calculation of the importance-weighted neutron generation time. The influence of reflector thickness on importance-weighted neutron generation time has been investigated by the development of an auxiliary code, IWLA, for a hypothetic assembly. The results of these calculations were compared with the non-weighted neutron generation times calculated using the Monte Carlo code MCNP. The difference between the importance-weighted and non-weighted quantity is more significant in a reflected system and increases with reflector thickness

  14. The applicability of detailed process for neutron resonance absorption to neutronics analyses in LWR next generation fuels to extend burnup

    International Nuclear Information System (INIS)

    Kameyama, Takanori; Nauchi, Yasushi

    2004-01-01

    Neutronics analyses with detail processing for neutron resonance absorption in LWR next generation UOX and MOX fuels to extend burnup were performed based on the neutronic transport and burnup calculation. In the detailed processing, ultra-fine energy nuclear library and collision probabilities between neutron and U, Pu nuclides (actinide nuclides) are utilized for two-dimension geometry. In the usual simple processing (narrow resonance approximation), shielding factors and compensation equations for neutron resonance absorption are utilized. The results with detailed and simple processing were compared to clarify where the detailed processing is needed. The two processing caused difference of neutron multiplication factor by 0.5% at the beginning of irradiation, while the difference became smaller as burnup increased and was not significant at high burnup. The nuclide compositions of the fuel rods for main actinide nuclides were little different besides Cm isotopes by the processing, since the neutron absorption rate of 244 Cm became different. The detail processing is needed to evaluate the neutron emission rate in spent fuels. In the fuel assemblies, the distributions of rod power rates were not different within 0.5%, and the peak rates of fuel rod were almost the same by the two processing at the beginning of irradiation when the peak rate is the largest during the irradiation. The simple processing is also satisfied for safety evaluation based on the peak rate of rod power. The difference of local power densities in fuel pellets became larger as burnup increased, since the neutron absorption rate of 238 U in the peripheral region of pellets were significantly different by the two processing. The detail processing is needed to evaluate the fuel behavior at high burnup. (author)

  15. EXPERIMENTAL ANALYSES OF SPALLATION NEUTRONS GENERATED BY 100 MEV PROTONS AT THE KYOTO UNIVERSITY CRITICAL ASSEMBLY

    Directory of Open Access Journals (Sweden)

    CHEOL HO PYEON

    2013-02-01

    Full Text Available Neutron spectrum analyses of spallation neutrons are conducted in the accelerator-driven system (ADS facility at the Kyoto University Critical Assembly (KUCA. High-energy protons (100 MeV obtained from the fixed field alternating gradient accelerator are injected onto a tungsten target, whereby the spallation neutrons are generated. For neutronic characteristics of spallation neutrons, the reaction rates and the continuous energy distribution of spallation neutrons are measured by the foil activation method and by an organic liquid scintillator, respectively. Numerical calculations are executed by MCNPX with JENDL/HE-2007 and ENDF/B-VI libraries to evaluate the reaction rates of activation foils (bismuth and indium set at the target and the continuous energy distribution of spallation neutrons set in front of the target. For the reaction rates by the foil activation method, the C/E values between the experiments and the calculations are found around a relative difference of 10%, except for some reactions. For continuous energy distribution by the organic liquid scintillator, the spallation neutrons are observed up to 45 MeV. From these results, the neutron spectrum information on the spallation neutrons generated at the target are attained successfully in injecting 100 MeV protons onto the tungsten target.

  16. A D-D neutron generator using a titanium drive-in target

    International Nuclear Information System (INIS)

    Kim, I.J.; Jung, N.S.; Jung, H.D.; Hwang, Y.S.; Choi, H.D.

    2008-01-01

    A D-D neutron generator was developed with an intensity of 10 8 n/s. A helicon plasma ion source was used to produce a large current deuteron beam, and neutrons were generated by irradiating the deuteron beam on a titanium drive-in target made of commercial pure titanium. The neutron generator was test-run for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 0.8-8 mA and the beam could be accelerated up to 97.5 keV. The maximum neutron generation rate in the test-runs was 1.9 x 10 8 n/s, which was achieved by irradiating a 7.6 mA deuteron beam at 94.0 keV on a 0.5 mm-thick target. The operation of the neutron generator was fairly stable, such that the neutron generation rate was not altered by high voltage breakdowns during the test-runs. Neutron generation efficiency was rated as low as 10% when compared to an ideal case of irradiating a 100% monatomic deuteron beam on a perfect TiD 2 target. Factors causing the low efficiency were suggested and discussed

  17. Prompt gamma-ray analysis of chlorine in superpozz cement concrete

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Kalakada, Zameer [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Ur-Rehman, Khateeb [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2012-11-21

    The chlorine concentration in Superpozz (SPZ) cement concrete was analyzed using a newly designed prompt gamma-ray neutron activation (PGNAA) setup utilizing a portable neutron generator. The setup, which mainly consists of a neutron source along with its moderator placed side by side with a shielded gamma-ray detector, allows determining chloride concentration in a concrete structure from one side. The setup has been tested through chlorine detection in chloride-contaminated Superpozz (SPZ) cement concrete specimens using 6.11 and 2.86{+-}3.10 MeV chlorine prompt gamma-rays. The optimum 0.032{+-}0.012 wt% value of Minimum Detectable Concentration (MDC) of chlorine in SPZ cement concrete measured in this study shows a successful application of a portable neutron generator in chloride analysis of concrete structure for corrosion studies.

  18. Calculation of the neutron importance and weighted neutron generation time using MCNIC method in accelerator driven subcritical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hassanzadeh, M. [Nuclear Science and Technology Research Institute, AEOI, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Feghhi, S.A.H., E-mail: a_feghhi@sbu.ac.ir [Department of Radiation Application, Shahid Beheshti University, G.C., Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Khalafi, H. [Nuclear Science and Technology Research Institute, AEOI, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2013-09-15

    Highlights: • All reactor kinetic parameters are importance weighted quantities. • MCNIC method has been developed for calculating neutron importance in ADSRs. • Mean generation time has been calculated in spallation driven systems. -- Abstract: The difference between non-weighted neutron generation time (Λ) and the weighted one (Λ{sup †}) can be quite significant depending on the type of the system. In the present work, we will focus on developing MCNIC method for calculation of the neutron importance (Φ{sup †}) and importance weighted neutron generation time (Λ{sup †}) in accelerator driven systems (ADS). Two hypothetic bare and graphite reflected spallation source driven system have been considered as illustrative examples for this means. The results of this method have been compared with those obtained by MCNPX code. According to the results, the relative difference between Λ and Λ{sup †} is within 36% and 24,840% in bare and reflected illustrative examples respectively. The difference is quite significant in reflected systems and increases with reflector thickness. In Conclusion, this method may be used for better estimation of kinetic parameters rather than the MCNPX code because of using neutron importance function.

  19. Calculation of the neutron importance and weighted neutron generation time using MCNIC method in accelerator driven subcritical reactors

    International Nuclear Information System (INIS)

    Hassanzadeh, M.; Feghhi, S.A.H.; Khalafi, H.

    2013-01-01

    Highlights: • All reactor kinetic parameters are importance weighted quantities. • MCNIC method has been developed for calculating neutron importance in ADSRs. • Mean generation time has been calculated in spallation driven systems. -- Abstract: The difference between non-weighted neutron generation time (Λ) and the weighted one (Λ † ) can be quite significant depending on the type of the system. In the present work, we will focus on developing MCNIC method for calculation of the neutron importance (Φ † ) and importance weighted neutron generation time (Λ † ) in accelerator driven systems (ADS). Two hypothetic bare and graphite reflected spallation source driven system have been considered as illustrative examples for this means. The results of this method have been compared with those obtained by MCNPX code. According to the results, the relative difference between Λ and Λ † is within 36% and 24,840% in bare and reflected illustrative examples respectively. The difference is quite significant in reflected systems and increases with reflector thickness. In Conclusion, this method may be used for better estimation of kinetic parameters rather than the MCNPX code because of using neutron importance function

  20. DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

    OpenAIRE

    Sunardi, Sunardi; Muryono, Muryono

    2010-01-01

    Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec).  At this research condition of neutron generator was set at...

  1. NGI-9 pulsed neutron generator with a fluence to 1010 n/s

    International Nuclear Information System (INIS)

    Allakhverdov, A.Sh.; Ogarkin, V.I.; Silicheva, G.P.; Timofeev, Yu.I.

    1975-01-01

    A neutron pulse generator with 14 MeV energy used for the activation analysis, is described. Its functional diagram and the technical characteristics are presented. The studies of the generator that resulted in determination of the effect of the accelerating voltage amplitude, the delay in the ion source firing with respect to the pulse of the accelerating voltage, the amount of operating ion sources and the energy imparted to them on the neutron flux magnitude are conducted. It is confirmed by the studies that the neutron generator operating in the nominal regime makes it possible to obtain a neutron flux of 5x10 9 -10 10 neutr./s. The dependence of the neutron flux variation on the frequency of pulse sequence for various ion sources is shown

  2. Instrumentation system for pulsed neutron generator. Pt. 1. Electronic control and data acquisition

    International Nuclear Information System (INIS)

    Burda, J.; Igielski, A.; Janik, W.; Kosik, M.; Kurowski, A.; Zaleski, T.

    1997-01-01

    The paper presents an electronic instrumentation system which is successfully applied for pulsed neutron generator and measurements. In the paper there are described in details all modernized parts of the system as well as new designed and applied ones. The set of diagrams is enclosed. An important part of the system has been designed and built in the Neutron Transport Physics Laboratory. (author)

  3. Generation of neutron cross sections library for the Thermos code of the Fuel management System (FMS)

    International Nuclear Information System (INIS)

    Alonso V, G.; Viais J, J.

    1990-10-01

    There is developed a method to generate the library of neutron cross sections for the Thermos code by means of the database ENDF-B/IV and the NJOY code. The obtained results are compared with the version previous of the library of neutron cross sections which was processed using the version ENDF-B/III. (Author)

  4. Neutron production and ion beam generation in plasma focus devices

    International Nuclear Information System (INIS)

    Steinmetz, K.

    1980-01-01

    Concerning the physical processes leading to neutron emission, a clearer situation has been achieved compared to the state at the start of this work. The general discussion will realize that the whole experimental data cannot be described consistently by the predictions of either the beam-target model or the quasi-thermonuclear fusion model, although many questions about the neutron production properties have been solved. In particular the neutron fluence anisotropy is found to be a property basically related to the existence of fast ions escaping axially out of the pinch region. The requirements to explain broad radial neutron energy spectra, long emission times, and energetic but not spatial emission anisotropies suggest a kind of particle trapping in the main source region. (orig./HT)

  5. Simulation and preliminary experimental results for an active neutron counter using a neutron generator for a fissile material accounting

    International Nuclear Information System (INIS)

    Ahn, Seong-Kyu; Lee, Tae-Hoon; Shin, Hee-Sung; Kim, Ho-Dong

    2009-01-01

    An active neutron coincidence counter using a neutron generator as an interrogation source has been suggested. Because of the high energy of the interrogation neutron source, 2.5 MeV, the induced fission rate is strongly affected by the moderator design. MCNPX simulation has been performed to evaluate the performance achieved with these moderators. The side- and bottom-moderator are significantly important to thermalize neutrons to induce fission. Based on the simulation results, the moderators are designed to be adapted to the experimental system. Their preliminary performance has been tested by using natural uranium oxide powder samples. For a sample of up to 3.5 kg, which contains 21.7 g of 235 U, 2.64 cps/g- 235 U coincidence events have been measured. Mean background error was 9.57 cps and the resultant coincidence error was 13.8 cps. The experimental result shows the current status of an active counting using a neutron generator which still has some challenges to overcome. However, the controllability of an interrogation source makes this system more applicable for a variety of combinations with other non-destructive methods like a passive coincidence counting especially under a harsh environment such as a hot cell. More precise experimental setup and tests with higher enriched samples will be followed to develop a system to apply it to an active measurement for the safeguards of a spent fuel treatment process.

  6. Optimization of Shielding- Collimator Parameters for ING-27 Neutron Generator Using MCNP5

    Directory of Open Access Journals (Sweden)

    Hegazy Aya Hamdy

    2018-01-01

    Full Text Available Neutron generators are now used in various fields. They produce only fast neutrons; D-D neutron generator produces 2.45 MeV neutrons and D-T produces 14.1 MeV neutrons. In order to optimize shielding-collimator parameters to achieve higher neutron flux at the investigated sample (The signal with lower neutron and gamma rays flux at the area of the detectors, design iterations are widely used. This work was applied to ROMASHA setup, TANGRA project, FLNP, Joint Institute for Nuclear Research. The studied parameters were; (1 shielding-collimator material, (2 Distance between the shielding-collimator assembly first plate and center of the neutron beam, and (3 thickness of collimator sheets. MCNP5 was used to simulate ROMASHA setup after it was validated on the experimental results of irradiation of Carbon-12 sample for one hour to detect its 4.44 MeV characteristic gamma line. The ratio between the signal and total neutron flux that enters each detector was calculated and plotted, concluding that the optimum shielding-collimator assembly is Tungsten of 5 cm thickness for each plate, and a distance of 2.3 cm. Also, the ratio between the signal and total gamma rays flux was calculated and plotted for each detector, leading to the previous conclusion but the distance was 1 cm.

  7. Development of High Intensity D-T fusion NEutron Generator (HINEG)

    Science.gov (United States)

    Wu, Yican; Liu, Chao; Song, Gang; Wang, Yongfeng; Li, Taosheng; Jiang, Jieqiong; Song, Yong; Ji, Xiang

    2017-09-01

    A high intensity D-T fusion neutron generator (HINEG) is keenly needed for the research and development (R&D) of nuclear technology and safety of the advanced nuclear energy system, especially for the radiation protection and shielding. The R&D of HINEG includes two phases: HINEG-I and HINEG-II. HINEG-I is designed to have both the steady beam and pulsed beam. The neutron yield of the steady beam is up to 1012 n/s. The width of pulse neutron beam is less than 1.5 ns. HINEG-I is used for the basic neutronics study, such as measurement of nuclear data, validation of neutronics methods and software, validation of radiation protection and so on. HINEG-II aims to generate a high neutron yield of 1013 n/s neutrons by adopting high speed rotating tritium target system integrated with jet/spray array enhanced cooling techniques, and can further upgrade to obtain neutron yield of 1014 1015n/s by using of accelerators-array in a later stage. HINEG-II can be used for fundamentals research of nuclear technology including mechanism of materials radiation damage and neutronics performance of components, radiation shielding as well as other nuclear technology applications.

  8. Optimization of Shielding- Collimator Parameters for ING-27 Neutron Generator Using MCNP5

    Science.gov (United States)

    Hegazy, Aya Hamdy; Skoy, V. R.; Hossny, K.

    2018-04-01

    Neutron generators are now used in various fields. They produce only fast neutrons; D-D neutron generator produces 2.45 MeV neutrons and D-T produces 14.1 MeV neutrons. In order to optimize shielding-collimator parameters to achieve higher neutron flux at the investigated sample (The signal) with lower neutron and gamma rays flux at the area of the detectors, design iterations are widely used. This work was applied to ROMASHA setup, TANGRA project, FLNP, Joint Institute for Nuclear Research. The studied parameters were; (1) shielding-collimator material, (2) Distance between the shielding-collimator assembly first plate and center of the neutron beam, and (3) thickness of collimator sheets. MCNP5 was used to simulate ROMASHA setup after it was validated on the experimental results of irradiation of Carbon-12 sample for one hour to detect its 4.44 MeV characteristic gamma line. The ratio between the signal and total neutron flux that enters each detector was calculated and plotted, concluding that the optimum shielding-collimator assembly is Tungsten of 5 cm thickness for each plate, and a distance of 2.3 cm. Also, the ratio between the signal and total gamma rays flux was calculated and plotted for each detector, leading to the previous conclusion but the distance was 1 cm.

  9. Development of High Intensity D-T fusion NEutron Generator (HINEG

    Directory of Open Access Journals (Sweden)

    Wu Yican

    2017-01-01

    Full Text Available A high intensity D-T fusion neutron generator (HINEG is keenly needed for the research and development (R&D of nuclear technology and safety of the advanced nuclear energy system, especially for the radiation protection and shielding. The R&D of HINEG includes two phases: HINEG-I and HINEG-II. HINEG-I is designed to have both the steady beam and pulsed beam. The neutron yield of the steady beam is up to 1012 n/s. The width of pulse neutron beam is less than 1.5 ns. HINEG-I is used for the basic neutronics study, such as measurement of nuclear data, validation of neutronics methods and software, validation of radiation protection and so on. HINEG-II aims to generate a high neutron yield of 1013 n/s neutrons by adopting high speed rotating tritium target system integrated with jet/spray array enhanced cooling techniques, and can further upgrade to obtain neutron yield of 1014~1015n/s by using of accelerators-array in a later stage. HINEG-II can be used for fundamentals research of nuclear technology including mechanism of materials radiation damage and neutronics performance of components, radiation shielding as well as other nuclear technology applications.

  10. Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

    International Nuclear Information System (INIS)

    Rhodes, E.; Peters, C.W.

    1991-01-01

    With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, can detect nuclear warheads by their characteristic strong gamma-ray absorption, or can count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. 5 refs., 12 figs

  11. Measurement of the average number of prompt neutrons emitted per fission of 235U relative to 252Cf for the energy region 500 eV to 10 MeV

    International Nuclear Information System (INIS)

    Gwin, R.; Spencer, R.R.; Ingle, R.W.; Todd, J.H.; Weaver, H.

    1980-01-01

    The average number of prompt neutrons emitted per fission ν/sub p/-bar(E), was measured for 235 U relative to ν/sub p/-bar for the spontaneous fission of 252 Cf over the neutron energy range from 500 eV to 10 MeV. The samples of 235 U and 252 Cf were contained in fission chambers located in the center of a large liquid scintillator. Fission neutrons were detected by the large liquid scintillator. The present values of ν/sub p/-bar(E) for 235 U are about 0.8% larger than those measured by Boldeman. In earlier work with the present system, it was noted that Boldeman's value of ν/sub p/-bar(E) for thermal energy neutrons was about 0.8% lower than obtained at ORELA. It is suggested that the thickness of the fission foil used in Boldeman's experiment may cause some of the discrepancy between his and the present values of ν/sub p/-bar(E). For the energy region up to 700 keV, the present values of ν/sub p/-bar(E) for 235 U agree, within the uncertainty, with those given in ENDF/B-V. Above 1 MeV the present results for ν/sub p/-bar(E) range about the ENDF/B-V values with differences up to 1.3%. 6 figures, 1 table

  12. Design and investigations of a DD compact neutron generator in head radiotherapy

    International Nuclear Information System (INIS)

    Araujo, Wagner; Campos, Tarcisio Passos Ribeiro

    2013-01-01

    Neutron generators are device-based particle accelerators for producing neutrons through fusion reactions between hydrogen isotopes. Such devices may enable noninvasive treatments of head and neck tumors, which represent about one hundred twenty-nine thousand cases per year around the world. The present paper shows electromagnetic and nuclear simulations of a neutron generator coupled to collimator and evaluations of radiation dose in an analytical head phantom irradiated by the device. The results provide the generator design and the operation parameter in order to achieve prescribed tumor dose. Also, dose distribution in organs of head is presented, being suitable to surrounding brain tumors close to the skull. As conclusion, there is a visibility of neutron generator applied to brain tumor radiation therapy. (author)

  13. Onset of collectivity in neutron-rich Sr and Kr isotopes: Prompt spectroscopy after Coulomb excitation at REX-ISOLDE, CERN

    Directory of Open Access Journals (Sweden)

    Clément E.

    2013-12-01

    Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N = 60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

  14. Symposium on CIAE 600 kV ns pulse neutron generator

    International Nuclear Information System (INIS)

    Shen Guanren

    2001-01-01

    CIAE 600 kV ns Pulse Neutron Generator was built by China National Nuclear Corporation, which is an important facility mainly used for experimental researches of nuclear reactions induced by 14 MeV neutrons, experimental measurements of energy spectra of secondary neutrons and charged particles and macro-checking experiments of evaluated neutron database and dosimetry researches of neutrons and γ rays. It is the first home made one, but the fourth similar facility in the world. Six articles are included in this symposium. The articles details the general structure, radio frequency ion source, high current beam ns pulsed system, etc. The main technical problems resolved during development are discussed. And attentions and experiences in the generator adjustments are introduced

  15. A study on measurement of neutrons generated in radiation therapy – Measurement of neurons in CR-39 detection method

    International Nuclear Information System (INIS)

    Park, Cheol-Soo; Cho, Jae-Hwan; Lee, Hae-Kag; Lee, Sun-Yeob; Jang, Hyon-Chol; Dong, Kyung-Rae; Chung, Woon-Kwan; Jin, Lee; Moon, Deog-Hwan; Lee, Kwang-Sung; Yang, Nam-Oh; Cho, Moo-Seong

    2013-01-01

    Highlights: ► To measure the neutrons generated in a linear accelerator. ► Both fast neutrons and thermal neutrons produced an increase in the dose of neutrons generated with increasing irradiation dose. ► The generation of neutrons increased when a wedge filter was used. ► When the SRS cone that required a high dose was used, more neutrons were detected. -- Abstract: The CR-39 [diethylene glycol bis-(allylcarbonate)] neuron detection method was used to measure the dose of neutrons generated in X-ray (photon) therapy conducted in a linear accelerator, and to use high-energy photons as part of the clinical applications to examine the problems associated with the dose for patients caused by the generation of neutrons from high-energy photons used for cancer therapy. According to the experimental results, 0.35 mSv, 0.65 mSv 1.82 mSv of fast neutrons on average were generated from 1 Gy, 2 Gy and 5 Gy of photon irradiation, respectively, whereas 0.26 mSv, 0.56 mSv and 1.23 mSv of thermal neutrons were generated. Both fast neutrons and thermal neutrons produced an increase in the dose of neutrons generated with increasing irradiation dose. With in regard to the dose generated within and around the irradiation area of the photon rays, it was confirmed that more neutrons were generated within the irradiation area. A wedge filer was used to measure the generation of neutrons. According to the measurement results, the generation of neutrons increased when a wedge filter was used. When the SRS cone that required a high dose was used, more neutrons were detected than those in the previous experiment. When fast neutrons were used, 2.85 mSv neutrons on average were generated from 5 Gy of photon irradiation. When thermal neutrons were used, 1.37 mSv neutrons on average were generated from 5 Gy of photon irradiation. Overall, approximately 1.6 times and 1.12 times more fast and thermal neutrons, respectively, were generated than in the case of a general treatment with 5 Gy

  16. Measurements of the prompt neutron spectra in 233U, 235U, 239Pu thermal neutron fission in the energy range of 0.01-5 MeV and in 252Cf spontaneous fission in the energy range of 0.01-10 MeV

    International Nuclear Information System (INIS)

    Starostov, B.I.; Semenov, A.F.; Nefedov, V.N.

    1978-01-01

    The measurement results on the prompt neutron spectra in 233 U, 235 U, 239 Pu thermal neutron fission in the energy range of 0.01-5 MeV and in 252 Cf spontaneous fission in the energy range of 0.01-10 MeV are presented. The time-of-flight method was used. The exceeding of the spectra over the Maxwell distributions is observed at E 252 Cf neutron fission spectra. The spectra analysis was performed after normalization of the spectra and corresponding Maxwell distributions for one and the same area. In the range of 0.05-0.22 MeV the yield of 235 U + nsub(t) fission neutrons is approximately 8 and approximately 15 % greater than the yield of 252 Cf and 239 Pu + nsub(t) fission neutrons, respectively. In the range of 0.3-1.2 MeV the yield of 235 U + nsub(t) fission neutrons is 8 % greater than the fission neutron yield in case of 239 Pu + nsub(t) fission. The 235 U + nsub(t) and 233 U + nsub(t) fission neutron spectra do not differ from one another in the 0.05-0.6 MeV range

  17. Analysis of a shield design for a DT neutron generator test facility.

    Science.gov (United States)

    Chichester, D L; Pierce, G D

    2007-10-01

    Independent numerical simulations have been performed using the MCNP5 and SCALE5 radiation transport codes to evaluate the effectiveness of a concrete facility designed to shield personnel from neutron radiation emitted from DT neutron generators. The analysis considered radiation source terms of 14.1 MeV monoenergetic neutrons located at three discrete locations within the two test vaults in the facility, calculating neutron and photon dose rates at 44 locations around the facility using both codes. In addition, dose rate contours were established throughout the facility using the MCNP5 mesh tally feature. Neutron dose rates calculated outside of the facility are predicted to be below 0.01 mrem/h at all locations when all neutron generator source terms are operating within the facility. Similarly, the neutron dose rate in one empty test vault when the adjacent test vault is being utilized is also less then 0.01 mrem/h. For most calculation locations outside the facility the photon dose rates were less then the neutron dose rates by a factor of 10 or more.

  18. The applied research program of the High Flux Neutron Generator at the National Nuclear Center, Havana

    International Nuclear Information System (INIS)

    Perez, G.; Martin, G.; Ceballos, C.; Padron, I.; Shtejer, K.; Perez, N.; Guibert, R.; Ledo, L.M.; Cruz Inclan, Carlos

    2001-01-01

    The Havana High Flux Neutron Generator facility is an intense neutron source based on a 20 mA duoplasmatron ion source and a 250 kV high voltage power supply. It has been installed in the Neutron Generator Laboratory at the Center of Applied Technologies and Nuclear Research in 1997. This paper deal outlined the future applied program to be carried out in this facility in the next years. The Applied Research Program consists on install two nuclear analytic techniques: the PELAN technique which uses the neutron generator in the pulse mode and the Low Energy PIXE technique which uses the same facility as a low energy proton accelerator for PIXE analysis. (author)

  19. Nanotubes based neutron generator for calibration of neutrino and dark matter detectors

    Science.gov (United States)

    Chepurnov, A. S.; Ionidi, V. Y.; Kirsanov, M. A.; Kitsyuk, E. P.; Klenin, A. A.; Kubankin, A. S.; Oleinik, A. N.; Pavlov, A. A.; Shchagin, A. V.

    2017-12-01

    The compact 2.45 MeV fast neutron generator with a reduced supply voltage for calibration of low-background neutrino and dark matter detectors was tested. The generator is based on an array of carbon nanotubes. Neutron generation is carried out by applying a high voltage in the range of +10 to + 25 kV to a nanotube array, which cause an ionization of deuterium molecules with the following acceleration of ions in the direction of the grounded target covered by a deuterated polyethylene film. The d(d,n)3He nuclear reaction happens as the result of ions collisions with the target. The dependences of the neutron yield as functions of the applied voltage were obtained for two different types of carbon nanotubes array. It is shown that the type of nanotubes array does not influence significantly on the neutron yield.

  20. Monte Carlo simulations of a D-T neutron generator shielding for landmine detection

    International Nuclear Information System (INIS)

    Reda, A.M.

    2011-01-01

    Shielding for a D-T sealed neutron generator has been designed using the MCNP5 Monte Carlo radiation transport code. The neutron generator will be used in field for the detection of explosives, landmines, drugs and other 'threat' materials. The optimization of the detection of buried objects was started by studying the signal-to-noise ratio for different geometric conditions. - Highlights: → A landmine detection system based on neutron fast/slow analysis has been designed. → Shielding for a D-T sealed neutron generator tube has been designed using Monte Carlo radiation transport code. → Detection of buried objects was started by studying the signal-to-noise ratio for different geometric conditions. → The signal-to-background ratio optimized at one position for all depths.

  1. Applications of neutrons for laboratory and industrial activation analysis problems

    International Nuclear Information System (INIS)

    Szabo, Elek; Bakos, Laszlo

    1986-01-01

    This chapter presents some particular applications and case studies of neutrons in activation analysis for research and industrial development purposes. The reactor neutrons have been applied in Hungarian laboratories for semiconductor research, for analysis of geological (lunar) samples, and for a special comparator measurement of samples. Some industrial applications of neutron generator and sealed sources for analytical problems are presented. Finally, prompt neutron activation analysis is outlined briefly. (R.P.)

  2. Development and characterization of a D-D fast neutron generator for imaging applications.

    Science.gov (United States)

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

    2015-02-01

    The experimental characterization of a pulsed D-D fast neutron generator designed for fan-beam tomography applications is presented. Using Monte Carlo simulations the response of an LB6411 neutron probe was related to the neutron generator output. The yield was measured to be up to ∼10(7) neutrons/s. An aluminum block was moved stepwise between the source and a BC400 plastic scintillator detector in order to measure an edge response. This edge response was related to the neutron emitting spot size using Monte Carlo simulations and a simplified geometry-based model. The experimentally determined spot size of 2.2 mm agreed well with the simulated value of 1.5 mm. The time-dependence of pulsed output for various operating conditions was also measured. The neutron generator was found to satisfy design requirements for a planned fast neutron tomography arrangement based on a plastic scintillator detector array which is expected to be capable of producing 2D tomograms with a resolution of ∼1.5 mm. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

    Directory of Open Access Journals (Sweden)

    Sunardi Sunardi

    2010-06-01

    Full Text Available Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec.  At this research condition of neutron generator was set at current 1 mA that produced neutron flux about 5,47.107 n/cm2.s and  experimental result shown that the limit detection for the elements N, P, K, Si, Al, Fe, Cu, Cd are  2,44 ppm, 1,88 ppm, 2,15 ppm, 1,44 ppm, 1,26 ppm, 1,35 ppm, 1,05 ppm, 2,99 ppm, respectively.  The data  indicate that the limit detection or sensitivity of appliance of neutron generator to analyze the element is very good, which is feasible to get accreditation AANC laboratory using neutron generator.   Keywords: limit detection, AANC, neutron generator

  4. Loss of the associated α-particles in the tagged neutron generators

    Energy Technology Data Exchange (ETDEWEB)

    Sudac, D.; Nad, K.; Obhodas, J. [Institute Ruder Boskovic, P.O. Box 180, 10002 Zagreb (Croatia); Bystritsky, V.M. [Joint Institute for Nuclear Research, Moscow region, Dubna 141 980 (Russian Federation); Valkovic, V., E-mail: valkovic@irb.hr [Kvinticka 62, 10000 Zagreb (Croatia)

    2015-09-01

    The reported loss of α-particles in the 14 MeV tagged neutron generators has been investigated using two neutron generators equipped with α-particle counters and two neutron detectors. One neutron detector was put right in the middle of the tagged neutron cone and another one was put outside the cone. By measuring the difference between double (neutron–neutron) and triple (α-neutron-neutron) coincidences it is possible to deduce the α-particle loss since the number of triple coincidences should be equal to the number of double coincidences. In all measurements performed a deficit of triple with respect to double coincidences has been observed. This deficit was smallest for the threshold of α-particle Constant Fraction Discriminator (αCFD) being 0 and maximum allowed voltage of α-particle detector being −1.7 kV. The smallest measured deficit value was equal to 13±1%. From the observed results it was concluded that the deficit was due to a number of non-detected α-particles that loose sufficient quantity of energy while traveling to the detector because of collisions with particles present in the neutron tube and/or in the tritium target. These α-particles will not be detected as they fall under the threshold of αCFD discriminator. Magnetic fields present in the system worsen the situation since they are forcing α-particles to travel larger distances because of toroidal movement and undergoing additional collisions. Tagged neutron technique has many kind of applications and it is particularly important for high accuracy nuclear cross-sections measurements when α-particles losses must be carefully assessed.

  5. New perspectives from new generations of neutron sources

    Science.gov (United States)

    Mezei, Ferenc

    2007-09-01

    Since the early 1950s the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advance—primarily achieved by improving the scattering instruments—the maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the USA (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. To cite this article: F. Mezei, C. R. Physique 8 (2007).

  6. New perspectives from new generations of neutron sources

    International Nuclear Information System (INIS)

    Mezei, F.

    2007-01-01

    Since the early fifties the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advance - primarily achieved by improving the scattering instruments - the maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the Usa (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. (author)

  7. Calibration of a D-T neutron generator

    International Nuclear Information System (INIS)

    Ito, Tadayuki

    1980-01-01

    The energy and production rate of neutrons from a thick target are discussed. The production rate of D-T neutrons is estimated by counting alpha particles with a silicon detector. In this case, it is necessary to evaluate a correction factor from the energy of deuteron, the reaction cross section, the stopping power of target materials and others. The factor was calculated and is shown in a figure. The energy spectrum of emitted neutrons is also estimated, where the atomic ratio of T and Ti is taken as a parameter. The shape of the spectrum is determined by the reaction cross section, and is not dependent on the ratio T/Ti. The errors due to competitive reactions, such as D(d, n) and D(d, p), are negligible. It is necessary for mutual comparison to take care of the target thickness, the acceleration voltage of D beam, the alpha-detector position, and the gain fluctuation of electronic circuits. (Kato, T.)

  8. Tests of the space gamma spectrometer prototype at the JINR experimental facility with different types of neutron generators

    Science.gov (United States)

    Litvak, M. L.; Vostrukhin, A. A.; Golovin, D. V.; Dubasov, P. V.; Zontikov, A. O.; Kozyrev, A. S.; Krylov, A. R.; Krylov, V. A.; Mitrofanov, I. G.; Mokrousov, M. I.; Repkin, A. N.; Timoshenko, G. N.; Udovichenko, K. V.; Shvetsov, V. N.

    2017-07-01

    The results of the tests of the HPGe gamma spectrometer performed with a planetary soil model and different types of pulse neutron generators are presented. All measurements have been performed at the experimental nuclear planetary science facility (Joint Institute for Nuclear Research) for the physical calibration of active gamma and neutron spectrometers. The aim of the study is to model a space experiment on determining the elemental composition of Martian planetary matter by neutron-induced gamma spectroscopy. The advantages and disadvantages of a gas-filled neutron generator in comparison with a vacuum-tube neutron generator are examined.

  9. Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

    Science.gov (United States)

    Skalyga, V; Izotov, I; Golubev, S; Razin, S; Sidorov, A; Maslennikova, A; Volovecky, A; Kalvas, T; Koivisto, H; Tarvainen, O

    2015-12-01

    BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for. A so-called high current quasi-gasdynamic ECR ion source with plasma heating by millimeter wave gyrotron radiation is suggested to be used in a scheme of D-D neutron generator in the present work. Ion source of that type was developed in the Institute of Applied Physics of Russian Academy of Sciences (Nizhny Novgorod, Russia). It can produce deuteron ion beams with current density up to 700-800 mA/cm(2). Generation of the neutron flux with density at the level of 7-8·10(10) s(-1) cm(-2) at the target surface could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV. Estimations show that it is enough for formation of epithermal neutron flux with density higher than 10(9) s(-1) cm(-2) suitable for BNCT. Important advantage of described approach is absence of Tritium in the scheme. First experiments performed in pulsed regime with 300 mA, 45 kV deuteron beam directed to D2O target demonstrated 10(9) s(-1) neutron flux. This value corresponds to theoretical estimations and proofs prospects of neutron generator development based on high current quasi-gasdynamic ECR ion source. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Determination of the emission rate for the 14 MeV neutron generator with the use of radio-yttrium

    Directory of Open Access Journals (Sweden)

    Laszynska Ewa

    2015-06-01

    Full Text Available The neutron emission rate is a crucial parameter for most of the radiation sources that emit neutrons. In the case of large fusion devices the determination of this parameter is necessary for a proper assessment of the power release and the prediction for the neutron budget. The 14 MeV neutron generator will be used for calibration of neutron diagnostics at JET and ITER facilities. The stability of the neutron generator working parameters like emission and angular homogeneity affects the accuracy of calibration other neutron diagnostics. The aim of our experiment was to confirm the usefulness of yttrium activation method for monitoring of the neutron generator SODERN Model: GENIE 16. The reaction rate induced by neutrons inside the yttrium sample was indirectly measured by activation of the yttrium sample, and then by means of the γ-spectrometry method. The pre-calibrated HPGe detector was used to determine the yttrium radioactivity. The emissivity of neutron generator calculated on the basis of the measured radioactivity was compared with the value resulting from its electrical settings, and both of these values were found to be consistent. This allowed for a positive verification of the reaction cross section that was used to determine the reaction rate (6.45 × 10−21 reactions per second and the neutron emission rate (1.04 × 108 n·s−1. Our study confirms usefulness of the yttrium activation method for monitoring of the neutron generator.

  11. Design of analytical instrumentation with D-T sealed neutron generators

    International Nuclear Information System (INIS)

    Qiao Yahua; Wu Jizong; Zheng Weiming; Liu Quanwei; Zhang Min

    2008-01-01

    Analytical instrumentation with D-T sealed neutron generators source activation, The 14 MeV D-T sealed neutron tube with 10 9 n · s -1 neutron yield is used as generator source. The optimal structure of moderator and shield was achieved by MC computing.The instrumentation's configuration is showed. The instrumentation is made up of the SMY-DT50.8-2.1 sealed neutron tube and the high-voltage power supply system, which center is the sealed neutron generators. 6 cm Pb and 20 cm polythene is chosen as moderator, Pb, polythene and 10 cm boron-PE was chosen as shield .The sample box is far the source from 9 cm, the measurement system were made up of HPGe detector and the sample transforming system. After moderator and shield, the thermal neutron fluence rate at the point of sample is 0.93 × 10 6 n · s -1 cm -2 , which is accorded with design demand, and the laboratory and surroundings reaches the safety standard of the dose levels. (authors)

  12. Next Generation Neutron Scintillators Based On Semiconductor Nanostructures

    International Nuclear Information System (INIS)

    Wang, Cai-Lin

    2008-01-01

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

  13. A compact neutron generator using a field ionization source.

    Science.gov (United States)

    Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali; Schenkel, Thomas

    2012-02-01

    Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-fibers promise the high field-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of field emitters with a density up to 10(6) tips∕cm(2) and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.

  14. Experimental subcritical facility driven by D-D/D-T neutron generator at BARC, India

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Amar, E-mail: image@barc.gov.in; Roy, Tushar; Kashyap, Yogesh; Ray, Nirmal; Shukla, Mayank; Patel, Tarun; Bajpai, Shefali; Sarkar, P.S.; Bishnoi, Saroj

    2015-05-01

    Highlights: •Experimental subcritical facility BRAHMMA coupled to D-D/D-T neutron generator. •Preliminary results of PNS experiments reported. •Feynman-alpha noise measurements explored with continuous source. -- Abstract: The paper presents design of an experimental subcritical assembly driven by D-D/D-T neutron and preliminary experimental measurements. The system has been developed for investigating the static and dynamic neutronic properties of accelerator driven sub-critical systems. This system is modular in design and it is first in the series of subcritical assemblies being designed. The subcritical core consists of natural uranium fuel with high density polyethylene as moderator and beryllium oxide as reflector. The fuel is embedded in high density polyethylene moderator matrix. Estimated k{sub eff} of the system is ∼0.89. One of the unique features of subcritical core is the use of Beryllium oxide (BeO) as reflector and HDPE as moderator making the assembly a compact modular system. The subcritical core is coupled to Purnima Neutron Generator which works in D-D and D-T mode with both DC and pulsed operation. It has facility for online source strength monitoring using neutron tagging and programmable source modulation. Preliminary experiments have been carried out for spatial flux measurement and reactivity estimation using pulsed neutron source (PNS) techniques with D-D neutrons. Further experiments are being planned to measure the reactivity and other kinetic parameters using noise methods. This facility would also be used for carrying out studies on effect of source importance and measurement of source multiplication factor k{sub s} and external neutron source efficiency φ{sup ∗} in great details. Experiments with D-T neutrons are also underway.

  15. Calculation of neutron spectra produced in neutron generator target: Code testing.

    Science.gov (United States)

    Gaganov, V V

    2018-03-01

    DT-neutron spectra calculated using the SRIANG code was benchmarked against the results obtained by widely used Monte Carlo codes: PROFIL, SHORIN, TARGET, ENEA-JSI, MCUNED, DDT and NEUSDESC. The comparison of the spectra obtained by different codes confirmed the correctness of SRIANG calculations. The cross-checking of the compared spectra revealed some systematic features and possible errors of analysed codes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

    Science.gov (United States)

    Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

    2017-04-01

    We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

  17. Sealed operation of a rf driven ion source for a compact neutron generator to be used for associated particle imaging.

    Science.gov (United States)

    Wu, Y; Hurley, J P; Ji, Q; Kwan, J W; Leung, K N

    2010-02-01

    We present the recent development of a prototype compact neutron generator to be used in conjunction with the method of associated particle imaging for the purpose of active neutron interrogation. In this paper, the performance and device specifications of these compact generators that employ rf driven ion sources will be discussed. Initial measurements of the generator performance include a beam spot size of 1 mm in diameter and a neutron yield of 2x10(5) n/s with air cooling.

  18. Overview of the Division 2351 Neutron Generator Test Facility waveform digitizing system

    International Nuclear Information System (INIS)

    Bryant, T.C. Jr.

    1978-02-01

    All neutron generator waveforms from units tested at the SLA neutron generator test site are digitized and the digitized data stored in the CDC 6600 tape library for display and analysis using the CDC 6600 computer. The digitizing equipment consists mainly of seven Biomation Model 8100 transient recorders, Digital Equipment Corporation PDP 11/20 computer, RK05 disk, seven-track magnetic tape transport, and appropriate DEC and SLA controllers and interfaces. The PDP 11/20 computer is programmed in BASIC with assembly language drivers. In addition to digitizing waveforms, this equipment is used for other functions such as the automated testing of multiple-operation electronic neutron generators. Although other types of analysis have been done, the largest use of the digitized data has been for various types of graphical displays using the CDC 6600 and either the SD4020 or DX4460 plotters

  19. Perspectives of development of linac-driver for the ITEP neutron generator

    International Nuclear Information System (INIS)

    Kozodaev, A.M.; Vengrov, R.M.; Drozdovskij, A.A.; Kolomiets, A.A.; Orlov, Yu.G.; Raskopin, A.M.; Skachkov, V.S.; Shvedov, O.V.

    1999-01-01

    The perspectives of developing the experimental accelerator-driven neutron generator being made in ITEP are discussed. The ITEP ADS neutron generator consists of the target-blanket assembly and the linear proton accelerator Istra-36. It is projected to introduce superconducting sections in the composition of the neutron generator linac-driven. The application of superconducting resonators allows to increase the particle energy up to 53 MeV at the average beam current 500 μA. The variants of raising the average current up to 5 mA by increasing the HF-system power are considered. The application of magnetohard materials permits to decrease the cost of the bend magnet and its dimensions. To improve the radiation situation it is proposed to use the graphite absorbers of particles [ru

  20. New generation of cryogen free advanced superconducting magnets for neutron scattering experiments

    International Nuclear Information System (INIS)

    Kirichek, O; Adroja, D T; Manuel, P; Bewley, R I; Brown, J; Kouzmenko, G; Wotherspoon, R

    2012-01-01

    Recent advances in superconducting technology and cryocooler refrigeration have resulted in a new generation of advanced superconducting magnets for neutron beam applications. These magnets have outstanding parameters such as high homogeneity and stability at highest magnetic fields possible, a reasonably small stray field, low neutron scattering background and larger exposure to neutron detectors. At the same time the pulse tube refrigeration technology provides a complete re-condensing regime which allows to minimise the requirements for cryogens without introducing additional noise and mechanical vibrations. The magnets can be used with dilution refrigerator insert which expands the temperature range from 20mK to 300K. Here we are going to present design, test results and the operational data of the 14T magnet for neutron diffraction and the 9T wide angle chopper magnet for neutron spectroscopy developed by Oxford Instruments in collaboration with ISIS neutron source. First scientific results obtained from the neutron scattering experiments with these magnets are also going to be discussed.

  1. Laser driven compression and neutron generation with spherical shell targets

    International Nuclear Information System (INIS)

    Campbell, P.M.; Hammerling, P.; Johnson, R.R.; Kubis, J.J.; Mayer, F.J.

    1977-01-01

    Laser-driven implosion experiments using DT-gas-filled spherical glass-shell targets are described. Neutron yields to 5 x 10 7 are produced from implosions of small ( -- 55 μm-diameter) targets spherically illuminated with an on-target laser power of 0.4 terawatt. Nuclear reaction product diagnostics, X-ray pinhole photographs, fast-ion spectra and X-ray measurements are used in conjunction with hydrodynamic computer code simulations to investigate the implosion phenomenology as well as the target corona evolution. Simulations using completely classical effects are not able to describe the full range of experimental data. Electron or radiation preheating may be required to explain some implosion measurements. (auth.)

  2. Flux gain for a next-generation neutron reflectometer resulting from improved supermirror performance

    CERN Document Server

    Rehm, C

    2002-01-01

    Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror neutron guides with very high critical angles for total reflection. In this contribution, we will discuss how the performance of a modern neutron-scattering instrument depends on the efficiency of these supermirrors. We summarize current limitations of supermirror coatings and outline ideas for enhancing their performance, particularly for improving the reflec...

  3. The intense neutron generator INGE-1 at the Technical University of Dresden

    International Nuclear Information System (INIS)

    Bittner, M.; Meisner, A.; Paffrath, E.; Schwiers, H.; Seeliger, D.

    1989-01-01

    The INGE-1 neutron generator developed for intergal 14 MeV neutron experiments is described. The accelerator produces steady d + ion beam in the current range of 1-10 mA with 120-240 keV energies at the target position. The beam is produced with a combined duoplasmatron focalization system on high voltage. A 30 keV beam is accelerated on final energy by a two-gap acceleration tube. The estimations conducted show that the generator maximum strength can reach up to 2x10 12 s -1 at 10 mA beam current and 220 keV energy. 4 refs

  4. Measurements of neutron-induced capture and fission reactions on $^{235}$ U: cross sections and ${\\alpha}$ ratios, photon strength functions and prompt ${\\gamma}$-ray from fission

    CERN Multimedia

    We propose to measure the neutron-induced capture cross section of the fissile isotope $^{235}$U using a fission tagging set-up. This new set-up has been tested successfully in 2010 and combines the n_TOF 4${\\pi}$ Total Absorption Calorimeter (TAC) with MicroMegas (MGAS) fission detectors. It has been proven that such a combination of detectors allows distinguishing with very good reliability the electromagnetic cascades from the capture reactions from dominant ${\\gamma}$-ray background coming from the fission reactions. The accurate discrimination of the fission background is the main challenge in the neutron capture cross section measurements of fissile isotopes. The main results from the measurement will be the associated capture cross section and ${\\alpha}$ ratio in the resolved (0.3-2250 eV) and unresolved (2.25-30 keV) resonance regions. According to the international benchmarks and as it is mentioned in the NEA High Priority Request List (HPRL), the 235U(n,${\\gamma}$) cross section is of utmost impo...

  5. The neutron and gamma-ray dose characterization using the Monte Carlo method to study the feasibility of the Prompt Gamma Activation Analysis technique at IPR-R1 TRIGA reactor in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Bruno T.; Soares, Alexandre L.; Grynberg, Suely E.; Menezes, Maria Angela B.C., E-mail: brunoteixeiraguerra@yahoo.com.br, E-mail: menezes@cdtn.br, E-mail: asleal@cdtn.br, E-mail: seg@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The IPR-R1 is a reactor type TRIGA, Mark-I model, manufactured by the General Atomic Company and installed at Nuclear Technology Development Centre (CDTN) of Brazilian Nuclear Energy Commission (CNEN), in Belo Horizonte, Brazil. It is a light water moderated and cooled, graphite-reflected, open-pool type research reactor. IPR-R1 works at 100 kW but it will be briefly licensed to operate at 250 kW. It presents low power, low pressure, for application in research, training and radioisotopes production. The fuel is an alloy of zirconium hydride and uranium enriched at 20% in {sup 235}U. The Implementation of the PGNAA (Prompt Gamma Neutron Activation Analysis) Technical at the TRIGA IPR-R1 research reactor of the CDTN will significantly increase in the types of matrices analyzable. A project is underway in order to implement this technique in CDTN. In order of verified the feasibility of the PGNAA at the TRIGA reactor, the MCNP (Monte Carlo N-Particle) method is used to theoretical calculations. This paper presents the results of a preliminary study of the neutron and gamma-ray dose in the room where the reactor is located, in case of implementation of this technique in the IPR-R1. (author)

  6. The neutron and gamma-ray dose characterization using the Monte Carlo method to study the feasibility of the Prompt Gamma Activation Analysis technique at IPR-R1 TRIGA reactor in Brazil

    International Nuclear Information System (INIS)

    Guerra, Bruno T.; Soares, Alexandre L.; Grynberg, Suely E.; Menezes, Maria Angela B.C.

    2013-01-01

    The IPR-R1 is a reactor type TRIGA, Mark-I model, manufactured by the General Atomic Company and installed at Nuclear Technology Development Centre (CDTN) of Brazilian Nuclear Energy Commission (CNEN), in Belo Horizonte, Brazil. It is a light water moderated and cooled, graphite-reflected, open-pool type research reactor. IPR-R1 works at 100 kW but it will be briefly licensed to operate at 250 kW. It presents low power, low pressure, for application in research, training and radioisotopes production. The fuel is an alloy of zirconium hydride and uranium enriched at 20% in 235 U. The Implementation of the PGNAA (Prompt Gamma Neutron Activation Analysis) Technical at the TRIGA IPR-R1 research reactor of the CDTN will significantly increase in the types of matrices analyzable. A project is underway in order to implement this technique in CDTN. In order of verified the feasibility of the PGNAA at the TRIGA reactor, the MCNP (Monte Carlo N-Particle) method is used to theoretical calculations. This paper presents the results of a preliminary study of the neutron and gamma-ray dose in the room where the reactor is located, in case of implementation of this technique in the IPR-R1. (author)

  7. High-Flux Neutron Generator Facility for Geochronology and Nuclear Physics Research

    Science.gov (United States)

    Waltz, Cory; HFNG Collaboration

    2015-04-01

    A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being commissioned at UC Berkeley. The generator is designed to produce monoenergetic 2.45 MeV neutrons at outputs exceeding 1011 n/s. The HFNG is designed around two RF-driven multi-cusp ion sources that straddle a titanium-coated copper target. D + ions, accelerated up to 150 keV from the ion sources, self-load the target and drive neutron generation through the d(d,n)3 He fusion reaction. A well-integrated cooling system is capable of handling beam power reaching 120 kW impinging on the target. The unique design of the HFNG target permits experimental samples to be placed inside the target volume, allowing the samples to receive the highest neutron flux (1011 cm-2 s-1) possible from the generator. In addition, external beams of neutrons will be available simultaneously, ranging from thermal to 2.45 MeV. Achieving the highest neutron yields required carefully designed schemes to mitigate back-streaming of high energy electrons liberated from the cathode target by deuteron bombardment. The proposed science program is focused on pioneering advances in the 40 Ar/39 Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science, and education. An end goal is to become a user facility for researchers. This work is supported by NSF Grant No. EAR-0960138, U.S. DOE LBNL Contract No. DE-AC02-05CH11231, U.S. DOE LLNL Contract No. DE-AC52-07NA27344, and UC Office of the President Award 12-LR-238745.

  8. Utilization of a sealed-tube neutron generator for training and research

    International Nuclear Information System (INIS)

    Jonah, S.A.

    2000-01-01

    The development of a program in nuclear science and technology in Nigeria began in 1976 with the establishment of two research centers, namely, the Centre for Energy Research and Training, (CERT), Zaria and the Centre for Energy Research and Development (CERD), Ile-Ife. The choice of Neutron Activation Analysis (NAA) technique as a very effective method of training scientists in basic and applied nuclear research led to the purchase of two KAMAN A-711 Neutron Generators for the two research centers. At CERT, the neutron generator (code named ZARABUNG-1) was successfully installed and the first 14 MeV neutrons were produced through the technical assistance of the International Atomic Energy Agency (IAEA) in 1988. In 1991, a new tube-head was purchased and installed due to the expiration of the old tube. Following the completion of its permanent site, the neutron generator was re-located from the old site and re-installed at the permanent site of CERT in 1995. (author)

  9. A novel design of beam shaping assembly to use D-T neutron generator for BNCT.

    Science.gov (United States)

    Kasesaz, Yaser; Karimi, Marjan

    2016-12-01

    In order to use 14.1MeV neutrons produced by d-T neutron generators, two special and novel Beam Shaping Assemblies (BSA), including multi-layer and hexagonal lattice have been suggested and the effect of them has been investigated by MCNP4C Monte Carlo code. The results show that the proposed BSA can provide the qualified epithermal neutron beam for BNCT. The final epithermal neutron flux is about 6e9 n/cm2.s. The final proposed BSA has some different advantages: 1) it consists of usual and well-known materials (Pb, Al, Fluental and Cd); 2) it has a simple geometry; 3) it does not need any additional gamma filter; 4) it can provide high flux of epithermal neutrons. As this type of neutron source is under development in the world, it seems that they can be used clinically in a hospital considering the proposed BSA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Staged Z-pinch Experiments at the 1MA Zebra pulsed-power generator: Neutron measurements

    Science.gov (United States)

    Ruskov, Emil; Darling, T.; Glebov, V.; Wessel, F. J.; Anderson, A.; Beg, F.; Conti, F.; Covington, A.; Dutra, E.; Narkis, J.; Rahman, H.; Ross, M.; Valenzuela, J.

    2017-10-01

    We report on neutron measurements from the latest Staged Z-pinch experiments at the 1MA Zebra pulsed-power generator. In these experiments a hollow shell of argon or krypton gas liner, injected between the 1 cm anode-cathode gap, compresses a deuterium plasma target of varying density. Axial magnetic field Bz neutron Time of Flight (nTOF) detectors are augmented with a large area ( 1400 cm2) liquid scintillator detector to which fast gatedPhotek photomultipliers are attached. Sample data from these neutron diagnostics systems is presented. Consistently high neutron yields YDD >109 are measured, with highest yield of 2.6 ×109 . A pair of horizontally and vertically placed plastic scintillator nTOFs suggest isotropic i.e. thermonuclear origin of the neutrons produced. nTOF data from the liquid scintillator detector was cross-calibrated with the silver activation detector, and can be used for accurate calculation of the neutron yield. Funded by the Advanced Research Projects Agency - Energy, under Grant Number DE-AR0000569.

  11. Sustaining knowledge in the neutron generator community and benchmarking study. Phase II.

    Energy Technology Data Exchange (ETDEWEB)

    Huff, Tameka B.; Stubblefield, William Anthony; Cole, Benjamin Holland, II; Baldonado, Esther

    2010-08-01

    This report documents the second phase of work under the Sustainable Knowledge Management (SKM) project for the Neutron Generator organization at Sandia National Laboratories. Previous work under this project is documented in SAND2008-1777, Sustaining Knowledge in the Neutron Generator Community and Benchmarking Study. Knowledge management (KM) systems are necessary to preserve critical knowledge within organizations. A successful KM program should focus on people and the process for sharing, capturing, and applying knowledge. The Neutron Generator organization is developing KM systems to ensure knowledge is not lost. A benchmarking study involving site visits to outside industry plus additional resource research was conducted during this phase of the SKM project. The findings presented in this report are recommendations for making an SKM program successful. The recommendations are activities that promote sharing, capturing, and applying knowledge. The benchmarking effort, including the site visits to Toyota and Halliburton, provided valuable information on how the SEA KM team could incorporate a KM solution for not just the neutron generators (NG) community but the entire laboratory. The laboratory needs a KM program that allows members of the workforce to access, share, analyze, manage, and apply knowledge. KM activities, such as communities of practice (COP) and sharing best practices, provide a solution towards creating an enabling environment for KM. As more and more people leave organizations through retirement and job transfer, the need to preserve knowledge is essential. Creating an environment for the effective use of knowledge is vital to achieving the laboratory's mission.

  12. Sustaining knowledge in the neutron generator community and benchmarking study. Phase II

    International Nuclear Information System (INIS)

    Huff, Tameka B.; Stubblefield, William Anthony; Cole, Benjamin Holland II; Baldonado, Esther

    2010-01-01

    This report documents the second phase of work under the Sustainable Knowledge Management (SKM) project for the Neutron Generator organization at Sandia National Laboratories. Previous work under this project is documented in SAND2008-1777, Sustaining Knowledge in the Neutron Generator Community and Benchmarking Study. Knowledge management (KM) systems are necessary to preserve critical knowledge within organizations. A successful KM program should focus on people and the process for sharing, capturing, and applying knowledge. The Neutron Generator organization is developing KM systems to ensure knowledge is not lost. A benchmarking study involving site visits to outside industry plus additional resource research was conducted during this phase of the SKM project. The findings presented in this report are recommendations for making an SKM program successful. The recommendations are activities that promote sharing, capturing, and applying knowledge. The benchmarking effort, including the site visits to Toyota and Halliburton, provided valuable information on how the SEA KM team could incorporate a KM solution for not just the neutron generators (NG) community but the entire laboratory. The laboratory needs a KM program that allows members of the workforce to access, share, analyze, manage, and apply knowledge. KM activities, such as communities of practice (COP) and sharing best practices, provide a solution towards creating an enabling environment for KM. As more and more people leave organizations through retirement and job transfer, the need to preserve knowledge is essential. Creating an environment for the effective use of knowledge is vital to achieving the laboratory's mission.

  13. Use of a pulsed neutron generator for in vivo measurement of body carbon

    International Nuclear Information System (INIS)

    Kehayias, J.J.; Ellis, K.J.; Cohn, S.H.; Yasumura, S.

    1986-01-01

    The measurement of total body fat is of importance in studies of nutritional assessment, dietary regimens, and for the management of obesity. In the past, fat has been determined either by anthropometric methods, which introduce high uncertainties, or by model-dependent estimation of fat-free tissue. The validity, however, of the different models in disease is questionable. Total body carbon measurements provide a more direct evaluation of body fat both in normal subjects and in patients. The authors present here a facility for carbon measurements without the use of a major accelerator. The same facility can be used for the measurement of other major body elements and for the evaluation of the body's compartments. Carbon is measured in vivo through neutron inelastic scattering, by detecting the 4.44 MeV gamma rays. A miniature (10 cm long) 14 MeV D-T neutron generator is used. The short half-life of the 4.44 MeV state of carbon requires detection of the gamma rays simultaneously with the 10 μs neutron pulse. Generators with low pulsing rate were found inappropriate for carbon measurement because of their low duty-cycle (high neutron output during pulse). The detection system consists of NaI(T1) detectors and fast electronics for handling the high even rate during the neutron pulse. A description of the facility and an evaluation of the technique will be presented

  14. SU-E-J-100: Reconstruction of Prompt Gamma Ray Three Dimensional SPECT Image From Boron Neutron Capture Therapy(BNCT)

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, D; Jung, J; Suh, T [The Catholic University of Korea, College of medicine, Department of biomedical engineering (Korea, Republic of)

    2014-06-01

    Purpose: Purpose of paper is to confirm the feasibility of acquisition of three dimensional single photon emission computed tomography (SPECT) image from boron neutron capture therapy (BNCT) using Monte Carlo simulation. Methods: In case of simulation, the pixelated SPECT detector, collimator and phantom were simulated using Monte Carlo n particle extended (MCNPX) simulation tool. A thermal neutron source (<1 eV) was used to react with the boron uptake region (BUR) in the phantom. Each geometry had a spherical pattern, and three different BURs (A, B and C region, density: 2.08 g/cm3) were located in the middle of the brain phantom. The data from 128 projections for each sorting process were used to achieve image reconstruction. The ordered subset expectation maximization (OSEM) reconstruction algorithm was used to obtain a tomographic image with eight subsets and five iterations. The receiver operating characteristic (ROC) curve analysis was used to evaluate the geometric accuracy of reconstructed image. Results: The OSEM image was compared with the original phantom pattern image. The area under the curve (AUC) was calculated as the gross area under each ROC curve. The three calculated AUC values were 0.738 (A region), 0.623 (B region), and 0.817 (C region). The differences between length of centers of two boron regions and distance of maximum count points were 0.3 cm, 1.6 cm and 1.4 cm. Conclusion: The possibility of extracting a 3D BNCT SPECT image was confirmed using the Monte Carlo simulation and OSEM algorithm. The prospects for obtaining an actual BNCT SPECT image were estimated from the quality of the simulated image and the simulation conditions. When multiple tumor region should be treated using the BNCT, a reasonable model to determine how many useful images can be obtained from the SPECT could be provided to the BNCT facilities. This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research

  15. Production of neutron-rich nuclei in fission induced by neutrons generated by the p+ sup 1 sup 3 C reaction at 55 MeV

    CERN Document Server

    Stroe, L; Andrighetto, A; Tecchio, L B; Dendooven, P; Huikari, J; Pentillä, H; Peraejaervi, K; Wang, Y

    2003-01-01

    Cross-sections for the production of neutron-rich nuclei obtained by neutron-induced fission of natural uranium have been measured. The neutrons were generated by bombarding a sup 1 sup 3 C target with 55 MeV protons. The results, position of the maximum in the (Z, A)-plane, width and magnitude, are very comparable with those where the neutrons are generated by bombardment of natural sup 1 sup 2 C graphite with 50 MeV deuterons. Depending on the geometry of the converter/target assembly the isotope yields, however, are a factor of 2-3 lower due to less efficient production of neutrons per primary projectile, especially at small forward angles. (orig.)

  16. Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

    Science.gov (United States)

    Bowman, Charles D.

    1992-01-01

    Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

  17. Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

    Science.gov (United States)

    Bowman, C.D.

    1992-11-03

    Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

  18. Copper benchmark experiment at the Frascati Neutron Generator for nuclear data validation

    Energy Technology Data Exchange (ETDEWEB)

    Angelone, M., E-mail: maurizio.angelone@enea.it; Flammini, D.; Loreti, S.; Moro, F.; Pillon, M.; Villari, R.

    2016-11-01

    Highlights: • A benchmark experiment was performed using pure copper with 14 MeV neutrons. • The experiment was performed at the Frascati Neutron Generator (FNG). • Activation foils, thermoluminescent dosimeters and scintillators were used to measure reactions rates (RR), nuclear heating and neutron spectra. • The paper presents the RR measurements and the post analysis using MCNP5 and JEFF-3.1.1, JEFF-3.2 and FENDL-3.1 libraries. • C/Es are presented showing the need for deep revision of Cu cross sections. - Abstract: A neutronics benchmark experiment on a pure Copper block (dimensions 60 × 70 × 60 cm{sup 3}), aimed at testing and validating the recent nuclear data libraries for fusion applications, was performed at the 14-MeV Frascati Neutron Generator (FNG) as part of a F4E specific grant (F4E-FPA-395-01) assigned to the European Consortium on Nuclear Data and Experimental Techniques. The relevant neutronics quantities (e.g., reaction rates, neutron flux spectra, doses, etc.) were measured using different experimental techniques and the results were compared to the calculated quantities using fusion relevant nuclear data libraries. This paper focuses on the analyses carried-out by ENEA through the activation foils techniques. {sup 197}Au(n,γ){sup 198}Au, {sup 186}W(n,γ){sup 187}W, {sup 115}In(n,n′){sup 115}In, {sup 58}Ni(n,p){sup 58}Co, {sup 27}Al(n,α){sup 24}Na, {sup 93}Nb(n,2n){sup 92}Nb{sup m} activation reactions were used. The foils were placed at eight different positions along the Cu block and irradiated with 14 MeV neutrons. Activation measurements were performed by means of High Purity Germanium (HPGe) detector. Detailed simulation of the experiment was carried-out using MCNP5 Monte Carlo code and the European JEFF-3.1.1 and 3.2 nuclear cross-sections data files for neutron transport and IRDFF-v1.05 library for the reaction rates in activation foils. The calculated reaction rates (C) were compared to the experimental quantities (E) and

  19. Pulsed neutron generator system for astrobiological and geochemical exploration of planetary bodies

    International Nuclear Information System (INIS)

    Akkurt, Hatice; Groves, Joel L.; Trombka, Jacob; Starr, Richard; Evans, Larry; Floyd, Samuel; Hoover, Richard; Lim, Lucy; McClanahan, Timothy; James, Ralph; McCoy, Timothy; Schweitzer, Jeffrey

    2005-01-01

    A pulsed neutron/gamma-ray detection system for use on rovers to survey the elemental concentrations of Martian and Lunar surface and subsurface materials is evaluated. A robotic survey system combining a pulsed neutron generator (PNG) and detectors (gamma ray and neutron) can measure the major constituents to a depth of about 30 cm. Scanning mode measurements can give the major elemental concentrations while the rover is moving; analyzing mode measurements can give a detailed elemental analysis of the adjacent material when the rover is stationary. A detailed map of the subsurface elemental concentrations will provide invaluable information relevant to some of the most fundamental astrobiological questions including the presence of water, biogenic activity, life habitability and deposition processes

  20. Prompt radiation detectors to monitor target conditions

    DEFF Research Database (Denmark)

    Barnhart, T. E.; Engle, J. W.; Valdovinos, H. F.

    2012-01-01

    Lessons learned by basic scientists in the study of experimental nuclear physics can often go unnoticed by cyclotron operator’s intent on meeting a demanding schedule of tracer production. Prompt neutrons and gammas are the signature that the desired reaction is occurring, providing a robust meas...

  1. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-06-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  2. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    International Nuclear Information System (INIS)

    Talamo, Alberto; Gohar, Yousry

    2016-01-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  3. Large area imaging of hydrogenous materials using fast neutrons from a DD fusion generator

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, J.T., E-mail: ted@adelphitech.com [Adelphi Technology Inc., 2003 East Bayshore Road, Redwood City, California 94063 (United States); Williams, D.L.; Gary, C.K.; Piestrup, M.A.; Faber, D.R.; Fuller, M.J.; Vainionpaa, J.H.; Apodaca, M. [Adelphi Technology Inc., 2003 East Bayshore Road, Redwood City, California 94063 (United States); Pantell, R.H.; Feinstein, J. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2012-05-21

    A small-laboratory fast-neutron generator and a large area detector were used to image hydrogen-bearing materials. The overall image resolution of 2.5 mm was determined by a knife-edge measurement. Contact images of objects were obtained in 5-50 min exposures by placing them close to a plastic scintillator at distances of 1.5 to 3.2 m from the neutron source. The generator produces 10{sup 9} n/s from the DD fusion reaction at a small target. The combination of the DD-fusion generator and electronic camera permits both small laboratory and field-portable imaging of hydrogen-rich materials embedded in high density materials.

  4. High-fidelity MCNP modeling of a D-T neutron generator for active interrogation of special nuclear material

    International Nuclear Information System (INIS)

    Katalenich, Jeff; Flaska, Marek; Pozzi, Sara A.; Hartman, Michael R.

    2011-01-01

    Fast and robust methods for interrogation of special nuclear material (SNM) are of interest to many agencies and institutions in the United States. It is well known that passive interrogation methods are typically sufficient for plutonium identification because of a relatively high neutron production rate from 240 Pu . On the other hand, identification of shielded uranium requires active methods using neutron or photon sources . Deuterium-deuterium (2.45 MeV) and deuterium-tritium (14.1 MeV) neutron-generator sources have been previously tested and proven to be relatively reliable instruments for active interrogation of nuclear materials . In addition, the newest generators of this type are small enough for applications requiring portable interrogation systems. Active interrogation techniques using high-energy neutrons are being investigated as a method to detect hidden SNM in shielded containers . Due to the thickness of some containers, penetrating radiation such as high-energy neutrons can provide a potential means of probing shielded SNM. In an effort to develop the capability to assess the signal seen from various forms of shielded nuclear materials, University of Michigan Neutron Science Laboratory's D-T neutron generator and its shielding were accurately modeled in MCNP. The generator, while operating at nominal power, produces approximately 1x10 10 neutrons/s, a source intensity which requires a large amount of shielding to minimize the dose rates around the generator. For this reason, the existing shielding completely encompasses the generator and does not include beam ports. Therefore, several MCNP simulations were performed to estimate the yield of uncollided 14.1-MeV neutrons from the generator for active interrogation experiments. Beam port diameters of 5, 10, 15, 20, and 25 cm were modeled to assess the resulting neutron fluxes. The neutron flux outside the beam ports was estimated to be approximately 2x10 4 n/cm 2 s.

  5. Design of the Next Generation Target at the Lujan Neutron Scattering Center, LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Ferres, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); National Graduate School of Engineering and Research Center (ENSICAEN), Caen (France)

    2016-08-03

    Los Alamos National Laboratory (LANL) supports scientific research in many diverse fields such as biology, chemistry, and nuclear science. The Laboratory was established in 1943 during the Second World War to develop nuclear weapons. Today, LANL is one of the largest laboratories dedicated to nuclear defense and operates an 800 MeV proton linear accelerator for basic and applied research including: production of high- and low-energy neutrons beams, isotope production for medical applications and proton radiography. This accelerator is located at the Los Alamos Neutron Science Center (LANSCE). The work performed involved the redesign of the target for the low-energy neutron source at the Lujan Neutron Scattering Center, which is one of the facilities built around the accelerator. The redesign of the target involves modeling various arrangements of the moderator-reflector-shield for the next generation neutron production target. This is done using Monte Carlo N-Particle eXtended (MCNPX), and ROOT analysis framework, a C++ based-software, to analyze the results.

  6. Experimental characterization of the neutron spectra generated by a high-energy clinical LINAC

    Energy Technology Data Exchange (ETDEWEB)

    Amgarou, K., E-mail: khalil.amgarou@uab.e [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Metrologie et de Dosimetrie des Neutrons, F-13115 Saint Paul-Lez-Durance (France); Lacoste, V.; Martin, A. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Laboratoire de Metrologie et de Dosimetrie des Neutrons, F-13115 Saint Paul-Lez-Durance (France)

    2011-02-11

    The production of unwanted neutrons by electron linear accelerators (LINACs) has attracted a special attention since the early 50s. The renewed interest in this topic during the last years is due mainly to the increased use of such machines in radiotherapy. Specially, in most of developing countries where many old teletherapy irradiators, based on {sup 60}Co and {sup 137}Cs radioactive sources, are being replaced with new LINAC units. The main objective of this work is to report the results of an experimental characterization of the neutron spectra generated by a high-energy clinical LINAC. Measurements were carried out, considering four irradiation configurations, by means of our recently developed passive Bonner sphere spectrometer (BSS) using pure gold activation foils as central detectors. This system offers the possibility to measure neutrons over a wide energy range (from thermal up to a few MeV) at pulsed, intense and complex mixed n-{gamma} fields. A two-step unfolding method that combines the NUBAY and MAXED codes was applied to derive the final neutron spectra as well as their associated integral quantities (in terms of total neutron fluence and ambient dose equivalent rates) and fluence-averaged energies.

  7. Uncertainty and sensitivity analysis in the neutronic parameters generation for BWR and PWR coupled thermal-hydraulic–neutronic simulations

    International Nuclear Information System (INIS)

    Ánchel, F.; Barrachina, T.; Miró, R.; Verdú, G.; Juanas, J.; Macián-Juan, R.

    2012-01-01

    Highlights: ► Best-estimate codes are affected by the uncertainty in the methods and the models. ► Influence of the uncertainty in the macroscopic cross-sections in a BWR and PWR RIA accidents analysis. ► The fast diffusion coefficient, the scattering cross section and both fission cross sections are the most influential factors. ► The absorption cross sections very little influence. ► Using a normal pdf the results are more “conservative” comparing the power peak reached with uncertainty quantified with a uniform pdf. - Abstract: The Best Estimate analysis consists of a coupled thermal-hydraulic and neutronic description of the nuclear system's behavior; uncertainties from both aspects should be included and jointly propagated. This paper presents a study of the influence of the uncertainty in the macroscopic neutronic information that describes a three-dimensional core model on the most relevant results of the simulation of a Reactivity Induced Accident (RIA). The analyses of a BWR-RIA and a PWR-RIA have been carried out with a three-dimensional thermal-hydraulic and neutronic model for the coupled system TRACE-PARCS and RELAP-PARCS. The cross section information has been generated by the SIMTAB methodology based on the joint use of CASMO-SIMULATE. The statistically based methodology performs a Monte-Carlo kind of sampling of the uncertainty in the macroscopic cross sections. The size of the sampling is determined by the characteristics of the tolerance intervals by applying the Noether–Wilks formulas. A number of simulations equal to the sample size have been carried out in which the cross sections used by PARCS are directly modified with uncertainty, and non-parametric statistical methods are applied to the resulting sample of the values of the output variables to determine their intervals of tolerance.

  8. Computational modeling of the axial-cylindrical inertial electrostatic confinement fusion neutron generator

    Science.gov (United States)

    Bromley, Blair Patrick

    2001-12-01

    The axial-cylindrical Inertial Electrostatic Confinement fusion neutron generator (IEC C-Device) is a high- voltage, low-pressure glow discharge device that produces neutrons from the deuterium-deuterium fusion reaction. Such a neutron source has potential applications for neutron activation analysis and capture therapies for cancer treatment. The IEC C-Device operating with deuterium fuel is modeled with the CHIMP computer code developed and written completely by the author to predict the fusion neutron generation rate and the plasma physics behavior using fundamental first principles. The CHIMP code is a time-dependent, spatially two-dimensional (r,z), particle-in-cell, Monte-Carlo-Collision (PIC-MCC) direct simulation model. The effects of secondary electron emission due to ion and electron impact on the metal electrodes and the glass walls and charge build-up on the glass wall are included. Either monatomic or molecular ions and electrons are modeled in a monatomic or molecular background neutral deuterium gas. CHIMP code predictions are compared against experimental results for the C-Device operating between 10 and 30 kV of anode voltage, between 10 and 40 mA of electrode current, and between 0.29 and 1.1 milliTorr of deuterium gas pressure. A calibration factor for the pressure accounts for the calibration of the ionization pressure gauge in the experiment, and an estimated pressure drop between the main chamber of the C-Device and the pressure gauge that is downstream of the exhaust port. Upgraded versions of the CHIMP code which have modifications to the algorithms for the boundary conditions, and which include charge exchange processes, and the contribution of fast neutrals to the neutron generation rate are also tested against several experimental data points. Although the CHIMP code gives predictions for the neutron generation rate that exhibit the same near-linear trends with current found in the experiment, it is apparent that at least five types of

  9. Proceedings of the 14. International Symposium on the Interaction of Fast Neutrons with Nuclei - Neutron Generators and Application - organized by the Technical University of Dresden

    International Nuclear Information System (INIS)

    Seeliger, D.; Jahn, U.

    1985-07-01

    The symposium was devoted to current problems of intense fast neutron sources, especially 14 MeV DT-neutron generators, and their broad spectrum of application in nuclear physics. 56 participants from 12 countries and the IAEA demonstrate the high interest on this selected topics. The submitted contributions can be divided into two general parts. The first one gives a review about the different possibilities of the technical and technological solution in development, the present status of operation and also the problems connected with the use of intense neutron sources. Various experimental arrangements for neutron spectroscopy, determination of nuclear data and theoretical aspects are the content of the second part. The participation in this meeting of designer and operators on the one hand and users of neutron sources on the other hand was a good choice and stimulated productive discussions during the conference. (author)

  10. About the possibility of using the field of the portable neutron generator for treatment of oncological diseases

    International Nuclear Information System (INIS)

    Stoyanov, A.Ph.; Dovbnya, A.N.; Tsymbal, V.A.

    2017-01-01

    The possibility of using a portable neutron generator (PNG) for the treatment of oncological diseases is being considered. It has been shown that when using PNG as a neutron source, it is possible to ensure sufficient therapeutic impact on sick cells, with minimal damage to healthy cells. It's about applying PNG in a brachytherapy tumor. It is important to note that the presence of a narrow ion- pipe- needle allows a neutron source to be placed close to the tumor, and thus to increase therapeutic influence. Numerical estimates of the density of neutrons and the consumed dose when using PNG for brachytherapy performed, it is shown that, for a short period of time (approx 1 minute), sufficient dose of radiation for therapy is absorbed. The calculations of the neutron field and absorbed dose are accomplished through a computer program developed by the authors based on the Monte Carlo method, designed to simulate the generation, movement, braking and absorption of neutrons.

  11. Procedure and apparatus for the examination of underground formations with a neutron generator

    International Nuclear Information System (INIS)

    Culver, R.B.

    1978-01-01

    A pulsed neutron generator in a well logging instrument, pulsed at a clock frequency of 20 KHz is described. Inelastic scatter gamma rays are detected during a first time interval coinciding with the neutron source being on and capture gamma rays are measured during a second interval subsequent to the end of each neutron burst. Only a single detected pulse, assuming detection occurs, is transmitted during each of the two detection intervals. Sync pulses are generated in the well logging instrument scaled down to a frequency of 200 Hz for transmission to the earth's surface. At the earth's surface, the scaled-down sync pulses are applied to a phase locked loop system for regenerating the sync pulses to the same frequency as that of the clock frequency used to pulse the neutron source and to open the detection gates in the borehole instrument. The regenerated sync pulses are used in the surface instrumentation to route the pulses occurring in the inelastic interval into one section of a multichannel analyzer memory and the pulses occurring in the capture interval into another section of the multichannel analyzer. The use of memory address decoders, subtractors and ratio circuits enables both a carbon/oxygen ratio and a silicon/calcium ratio to be struck substantially free of background radiation. (Auth.)

  12. Multi Elemental Study Using Prompt Gamma Technique

    International Nuclear Information System (INIS)

    Normanshah Dahing; Muhamad Samudi Yasir; Normanshah Dahing; Hanafi Ithnin; Mohd Fitri Abdul Rahman; Hearie Hassan

    2016-01-01

    In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. The system consists of collimated isotopic neutron source, Cf-252 with HPGe detector and Multichannel Analysis (MCA). Concrete with size of 10x10x10 cm 3 and 15x15x15 cm 3 were analysed as sample. When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively. The results obtained were compared with computer simulation, NAA and XRF as a part of reference and validation. The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed. (author)

  13. Research on determine the absolute neutron output of distributed pulse generators

    International Nuclear Information System (INIS)

    Li Bojun; Tang Zhangkui; Wang Dong; Yang Gaozhao; Peng Taiping

    2009-01-01

    In order to determine the absolute neutron output of distributed pulse generators, we deduced equivalent length to deal with experimental data, according to the different layout and weighting of multiple pulse generators. The deposited energy in scintillation crystal and the integral flux which drilling through crystal interface was simulated by MCNP code. The result shows the simulated proportion of different distributed pulse generators is approximately agreed with experimental data. The validity of the equivalent length model was proved by the consistent results between calculation and experimental data. (authors)

  14. A continuously self regenerating high-flux neutron-generator facility

    Science.gov (United States)

    Rogers, A. M.; Becker, T. A.; Bernstein, L. A.; van Bibber, K.; Bleuel, D. L.; Chen, A. X.; Daub, B. H.; Goldblum, B. L.; Firestone, R. B.; Leung, K.-N.; Renne, P. R.; Waltz, C.

    2013-10-01

    A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being constructed at UC Berkeley. The current generator, designed around two RF-driven multicusp deuterium ion sources, is capable of producing a neutron output of >1011 n/s. A specially designed titanium-coated copper target located between the ion sources accelerates D+ ions up to 150 keV, generating 2.45 MeV neutrons through the d(d,3He)n fusion reaction. Deuterium in the target is self loaded and regenerating through ion implantation, enabling stable and continuous long-term operation. The proposed science program is focused on pioneering advances in the 40Ar/39Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science research including statistical model studies of radiative-strength functions and level densities, and education. An overview of the facility and its unique capabilities as well as first measurements from the HFNG commissioning will be presented. Work supported by NSF Grant No. EAR-0960138, U.S. DOE LBL Contract No. DE-AC02-05CH11231, and U.S. DOE LLNL Contract No. DE-AC52-07NA27344.

  15. Prompt Gamma Ray Spectroscopy for process monitoring

    International Nuclear Information System (INIS)

    Zoller, W.H.; Holmes, J.L.

    1991-01-01

    Prompt Gamma Ray Spectroscopy (PGRS) is a very powerful analytical technique able to measure many metallic, contamination problem elements. The technique involves measurement of gamma rays that are emitted by nuclei upon capturing a neutron. This method is sensitive not only to the target element but also to the particular isotope of that element. PGRS is capable of measuring dissolved metal ions in a flowing system. In the field, isotopic neutron sources are used to produce the desired neutron flux ( 252 Cf can produce neutron flux of the order of 10 8 neutrons/cm 2 --sec.). Due to high penetrating power of gamma radiation, high efficiency gamma ray detectors can be placed in an appropriate geometry to maximize sensitivity, providing real-time monitoring with low detection level capabilities

  16. A Compact Self-Driven Liquid Lithium Loop for Industrial Neutron Generation

    Science.gov (United States)

    Stemmley, Steven; Szott, Matt; Kalathiparambil, Kishor; Ahn, Chisung; Jurczyk, Brian; Ruzic, David

    2017-10-01

    A compact, closed liquid lithium loop has been developed at the University of Illinois to test and utilize the Li-7(d,n) reaction. The liquid metal loop is housed in a stainless steel trench module with embedded heating and cooling. The system was designed to handle large heat and particle fluxes for use in neutron generators as well as fusion devices, solely operating via thermo-electric MHD. The objectives of this project are two-fold, 1) produce a high energy, MeV-level, neutron source and 2) provide a self-healing, low Z, low recycling plasma facing component. The flowing volume will keep a fresh, clean, lithium surface allowing Li-7(d,n) reactions to occur as well as deuterium adsorption in the fluid, increasing the overall neutron output. Expected yields of this system are 107 n/s for 13.5 MeV neutrons and 108 n/s for 2.45 MeV neutrons. Previous work has shown that using a tapered trench design prevents dry out and allows for an increase in velocity of the fluid at the particle strike point. For heat fluxes on the order of 10's MW/m2, COMSOL models have shown that high enough velocities ( 70 cm/s) are attainable to prevent significant lithium evaporation. Future work will be aimed at addressing wettability issues of lithium in the trenches, experimentally determine the velocities required to prevent dry out, and determine the neutron output of the system. The preliminary results and discussion will be presented. DOE SBIR project DE-SC0013861.

  17. Activation analysis course experiments with a 14-MeV neutron generator

    International Nuclear Information System (INIS)

    Miller, D.A.; Miller, G.E.

    1976-01-01

    The use of a 14 MeV neutron generator system in the radiochemistry teaching program of the Chemistry Department of the University of California at Irvine is described. Several different types of experiment are outlined to indicate the broad applicability of such a system to an instructional program in Chemistry. The program has encompassed instruction of undergraduates, graduate students and a Summer Institute Workshop for College Professors

  18. Finite fission chain length and symmetry around prompt-criticality

    International Nuclear Information System (INIS)

    Xie Qilin; Yin Yanpeng; Gao Hui; Huang Po; Fang Xiaoqiang

    2012-01-01

    Probability distribution of finite fission chain length was derived by assuming that all neutrons behave identically. Finite fission chain length was also calculated using a zero-dimension Monte-Carlo method based on point kinetics. Then symmetry of finite fission chain length probability distribution around prompt-criticality was deduced, which helps understanding the emission rate of delayed neutrons and initiation of fission chain in super-prompt-critical system. (authors)

  19. Flux Gain for Next-Generation Neutron-Scattering Instruments Resulting From Improved Supermirror Performance

    International Nuclear Information System (INIS)

    Rehm, C.

    2001-01-01

    Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror (SM) neutron guides with very high critical angles for total reflection. In this contribution, they discuss how the performance of modern neutron scattering instruments depends on the efficiency of these supermirrors. They outline ideas for enhancing the performance of the SM coatings, particularly for improving the reflectivity at the position of the critical wave vector transfer. A simulation program has been developed which allows different approaches for SM designs to be studied. Possible instrument performance gains are calculated for the example of the SNS reflectometer

  20. The Benchmark experiment on stainless steel bulk shielding at the Frascati neutron generator

    International Nuclear Information System (INIS)

    Batistoni, P.; Angelone, M.; Martone, M.; Pillon, M.; Rado, V.

    1994-11-01

    In the framework of the European Technology Program for NET/ITER, ENEA (Italian Agency for New Technologies, Energy and Environment) - Frascati and CEA (Commissariat a L'Energie Atomique) - Cadarache collaborated on a Bulk Shield Benchmark Experiment using the 14-MeV Frascati Neutron Generator (FNG). The aim of the experiment was to obtain accurate experimental data for improving the nuclear database and methods used in shielding designs, through a rigorous analysis of the results. The experiment consisted of the irradiation of a stainless steel block by 14-MeV neutrons. The neutron reaction rates at different depths inside the block were measured by fission chambers and activation foils characterized by different energy response ranges. The experimental results have been compared with numerical results calculated using both S N and Monte Carlo transport codes and as transport cross section library the European Fusion File (EFF). In particular, the present report describes the experimental and numerical activity, including neutron measurements and Monte Carlo calculations, carried out by the ENEA Italian Agency for New Technologies, Energy and Environment) team