Energy Technology Data Exchange (ETDEWEB)

Measurements of neutron and gamma-ray penetrations in an iron shield were performed up to a 60-cm depth in a tightly coupled source shield configuration with the fast-neutron reactor YAYOI as a source. Rates of neutron reactions and gamma-ray dose rates in the iron shield were obtained using activation foils and thermoluminescent dosimeters. Analyses of the experiments were made by using the DOT-III code with coupled neutron and gamma-ray cross sections from ENDF/B-IV and POPOP4 libraries. To obtain the source condition for the iron shield analyses, the calculated spectrum was adjusted to the measured reaction rates at the reactor shield boundary. The calculated neutron and gamma-ray distributions in the iron shield show fairly good agreement with the experiments. The effect of ...

Energy Technology Data Exchange (ETDEWEB)

Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ...

Energy Technology Data Exchange (ETDEWEB)

The themal neutron sensitivities of SEI and Toshiba FD-P10-7 radiophotoluminescent silver activated metaphosphate glass dosimeters have been measured and studied theoretically. The graphite thermal neutron column attached to the AEEW reactor NESTOR was utilised as a source of thermal neutrons with minimal fast neutron and gamma-ray contamination. Both the neutron removal and gamma correction measurement techniques were applied and these gave consistent results. It was found that the thermal neutron sensitivity of the Toshiba dosimeters is comparable to the most neutron intensitive thermoluminescent materials available. Because of their larger size and higher silver concentration, however, SEI dosimeters are an order of magnitude more neutron sensitive. The ...

International Nuclear Information System (INIS)

The registration of secondary cosmic ray neutrons is a convenient tool for the investigation of primary cosmic ray variations and for meteorological effects as well. At present a large network of neutron monitors exists, aiming at studies of cosmic ray variations which are related to interplanetary conditions and geomagnetic activity. At the same time cosmic ray variations may be related to some atmospheric processes. In this connection, using the data from two neutron monitors (a standard and a lead free one), a gamma detector from Moscow station and lead free neutron monitor at BEO Moussala, we studied the correlations between rain flows and neutron flux. In this study we used daily averages on the basis of 10 min data for the neutron flux, corrected for barometric pressure and data from local meteo-stations. The ...

International Nuclear Information System (INIS)

A database has been designed for storing, retrieving and analyzing information about samples, experimental conditions and results obtained by neutron activation analysis and gamma-ray spectrometry. It has been created using Microsoft ACCESS 2002 under a Windows operating system. The database has been designed not only for saving information but also for quality assurance and quality control purposes. The structure of the relational design has been discussed and demonstrated with a new graphical feature of ACCESS 2002 called PIVOTCHART. (author)

Energy Technology Data Exchange (ETDEWEB)

A thermal neutron imaging facility for real-time neutron radiography and computed tomography has recently been developed at the University of Texas TRIGA reactor. Extensive Monte Carlo design calculations were used to determine optimal design parameters of the neutron collimator system to avoid costly trial and error. Thermal neutron flux determined by gold foil activation is 5 {times} 10{sup 6} n/cm{sup 2}{center_dot}s at the primary imaging location with beam size of 22.5 cm in diameter. The collimation ratio can be varied from 125 to 235. The neutron-to-gamma ratio is 7.8 {times} 10{sup 6} n/cm{sup 2}{center_dot}mR. The facility has been tested for radiography and tomography applications and is now fully operational.

International Nuclear Information System (INIS)

When the history of neutrons is considered, three large discoveries are recalled, that is, the discovery of neutrons by Chadwick in 1932, the discovery of the nuclear fission of uranium by Hahn and Strassmann in 1938, and the continuation of chain reaction in nuclear fission by Fermi and others in 1942. In neutron capture reaction, the reaction cross section can become very large. The fields of research, to which neutrons have contributed most as the experimental probe, are neutron activation analysis and neutron diffraction. The development of the prompt gamma ray analyzer at the JRR-3M in Japan Atomic Energy Research Institute is reported. This method eliminates the various defects in ordinary neutron activation analysis. By installing the cold neutron ...

Science.gov (United States)

The induced radioactivity in the construction materials of a Cockcroft-- Walton type neutron generator was measured. Major activation products (/sup 24/ Na, /sup 28/Al, /sup 56/Mn, /sup 64/Cu, /sup 65/Ni, /sup 69m/Zn, /sup 88/Rb /sup 91/Sr /sup 101/Mo, /sup 187/W/ and resulting doses are tabulated. Results show that the highest gamma activities would be observed in the fluorescent bulbs, copper pipe, aluminum lattice rod, and the aluminum pipe clamp. Thermoluminescent dosimeter readings yield the highest doses for the copper pipe tee, copper pipe, and aluminum lattice rod. Results of measuremerts of the neutron and gamma dose profiles of the facility are shown. However the indication is clearly that the tritium target, compared to other components, is the major source of radiation both during and after shutdown. (UK)

Energy Technology Data Exchange (ETDEWEB)

The Albedo Theory was applied in order to develop an one-group algorithm for coupled neutron-gamma shielding calculations. The configuration analyzed consists of multilayered plane systems, where a incident neutron current generates gamma radiation through neutron-gamma reactions. The results obtained by Albedo Method and ANISN code have shown excellent agreement. (author)

Energy Technology Data Exchange (ETDEWEB)

Specific parts of several plants (fruits, leaves, stem, bark and roots) often used as medicines in the Indian Ayurvedic system have been analysed for 20 elements (As, Ba, Br, Ca, Cl, Co, Cr, Cu, Fe, K, Mn, Mo, Na, P, Rb, Sb, Sc, Se, Sr and Zn) by employing instrumental neutron activation analysis (INAA). The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted using high resolution gamma ray spectrometry. Most of the medicinal herbs have been found to be rich in one or more of the elements under study. (Author).

Energy Technology Data Exchange (ETDEWEB)

In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of {sup 6}Li and {sup 7}Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of {sup 6}Li and {sup 7}Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)

International Nuclear Information System (INIS)

The Albedo Theory was applied in order to develop an one-group algorithm for coupled neutron-gamma shielding calculations. The configuration analyzed consists of multilayered plane systems, where a incident neutron current generates gamma radiation through neutron-gamma reactions. The results obtained by Albedo Method and ANISN code have shown excellent agreement. (author)

International Nuclear Information System (INIS)

A multi-group neutron-gamma cross-section library in DTF-IV format is supplemented with electron production matrix to generate a coupled neutron-gamma-electron library. This is realized by estimating the contributions from Compton scattering, pair production and photoelectric effect to the electron production cross-sections. A novel application of this new library, which involves transport of neutrons, gammas and electrons, for estimating the Compton current due to a pulse of radiation in air is discussed.

International Nuclear Information System (INIS)

The coupled neutron-gamma cross section libraries BUGLE-80 and SAILOR are compared, with focus on gamma production and transport and its sensitivity to the thermal component of the neutron flux. In addition, the importance of the prompt versus delayed components of the gamma source is addressed. Although BUGLE-80 shows some discrepancies in the core region, the two libraries demonstrate similar capability in the vicinity of the pressure vessel and beyond. The delayed fission product gammas from the core have little impact on the local gamma fluxes beyond the pressure vessel. Although thermal neutron capture is the dominant component of the gamma source, there is little sensitivity of the gamma source to uncertainties in the thermal neutron cross sections, due to compensating ...

Energy Technology Data Exchange (ETDEWEB)

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

International Nuclear Information System (INIS)

In Japan, cosmetics claiming hormesis effect are available through Internet. Although these cosmetics show the contents, they never mention the minor elements and radioactive sources. The existence of radioisotopes, however, was observed by measurements of the gamma-rays with a HPGe detector. In this study, in order to clarify the contents of trace elements, the hormesis cosmetics including radioactive sources were analyzed using INAA, PGAA and NAA with multiple gamma-ray detection (NAAMG). Nineteen elements were analyzed quantitatively in hormesis cosmetics by INAA, PGAA and NAAMG and 16 elements were detected qualitatively by SEM-EPMA. (author)

International Nuclear Information System (INIS)

Full text: A Large Sample Neutron Activation Analysis (LSNAA) facility is under development at GRR-1 research reactor, NCSR 'Demokritos'. The LSNAA facility design incorporates sample irradiation in the reactor's graphite thermal neutron column and subsequent measurement of the activity induced at a gamma spectroscopy system with gamma ray transmission measurement options included. Monte Carlo neutron and photon transport code MCNP-4C was used to model the facility. Appropriate correction factors accounting for neutron field perturbation during sample irradiation, high purity germanium detector efficiency for the volume source and gamma ray self-absorption within the sample itself were derived. The results of the computations were experimentally verified by activation foil ...

Energy Technology Data Exchange (ETDEWEB)

The neutron capture cross sections of Sr-88 and Y-89 were measured in a quasi-stellar neutron spectrum for kT = 25 keV via the activation method. Relevant systematic uncertainties were determined experimentally by repeated activations under different conditions and with different samples. Gold was used as a cross section standard. The resulting stellar cross sections for kT = 30 keV are 6.13 + or - 0.18 mbarn for Sr-88 and 19.0 + or - 0.6 mbarn for Y-89. The partial cross section Sr-86(n, gamma) Sr-87m was measured to 48.1 + or - 1.2 mbarn. Compared to previous data, the associated uncertainties are reduced by factors of 3 and 5, respectively. The implications for s-process nucleosynthesis around magic neutron number N = 50 are discussed in the light of new information on neutron density and temperature. 38 refs.

Science.gov (United States)

The neutron capture cross sections of Sr-88 and Y-89 were measured in a quasi-stellar neutron spectrum for kT = 25 keV via the activation method. Relevant systematic uncertainties were determined experimentally by repeated activations under different conditions and with different samples. Gold was used as a cross section standard. The resulting stellar cross sections for kT = 30 keV are 6.13 + or - 0.18 mbarn for Sr-88 and 19.0 + or - 0.6 mbarn for Y-89. The partial cross section Sr-86(n, gamma) Sr-87m was measured to 48.1 + or - 1.2 mbarn. Compared to previous data, the associated uncertainties are reduced by factors of 3 and 5, respectively. The implications for s-process nucleosynthesis around magic neutron number N = 50 are discussed in the light of new information on neutron density and temperature.

International Nuclear Information System (INIS)

The National Ignition Facility (NIF) is a proposed Department of Energy facility which will contribute to the resolution of important Defense Program and inertial fusion energy issues for energy production in the future. The NIF will consist of a laser system with 192 independent beamlets transported to a target chamber. The target chamber is a multi-purpose structure that provides the interface between the target and the laser optics. The chamber must be capable of achieving moderate vacuum levels in reasonable times; it must remain dimensionally stable within micron tolerances, provide support for the optics, diagnostics, and target positioner; it must minimize the debris from the x-ray and laser light environments; and it must be capable of supporting external neutron shielding. The chamber must also be fabricated from a low neutron activation material. The fusion reaction in the target gives off ...

Science.gov (United States)

We present the latest developments for the radiation laboratory curriculum at the Department of Physics and Astronomy of Western Kentucky University. During the last decade, the Applied Physics Institute (API) at WKU accumulated various equipment for radiation experimentation. This includes various neutron sources (computer controlled d-t and d-d neutron generators, and isotopic 252 Cf and PuBe sources), the set of gamma sources with various intensities, gamma detectors with various energy resolutions (NaI, BGO, GSO, LaBr and HPGe) and the 2.5-MeV Van de Graaff particle accelerator. XRF and XRD apparatuses are also available for students and members at the API. This equipment is currently used in numerous scientific and teaching activities. Members of the API also developed a set of laboratory activities for undergraduate students taking classes from the physics ...

International Nuclear Information System (INIS)

GRR-1 is a 5MW open pool type research reactor with MTR-type fuel elements cooled and moderated by light water with beryllium reflectors at the two opposing sides of the core. A graphite thermal neutron column is adjusted to one side of the core. Six radial horizontal beam tubes are available, of which three contain in-pile collimators for neutron scattering instruments. The reactor is currently out of operation for inspection and refurbishment purposes. The core has been dismantled and the fuel elements are stored in the used fuel storage tank. The GRR-1 inspection and refurbishment plan involves inspection and eventually replacement of the reactor's primary cooling circuit. The health physics procedures to be implemented during inspection of the main water outlet are divided in three stages: a) pool dose rate survey from pool top, b) pool drainage by decreasing water level in steps and c) inspection of the water main outlet. urpose of the ...

CERN Document Server

beta- and gamma-decay studies of neutron-rich chromium, manganese, cobalt and nickel isotopes including the new isotopes $^{60}$Cr and $^{60g}$Mn

Science.gov (United States)

For abstract, see NSA 26 23, number 56263.

Energy Technology Data Exchange (ETDEWEB)

Safety and environmental assessments have been made of conceptual fusion power plant designs employing silicon carbide composites (SiC/SiC) as the first wall and blanket structure material. These have used similar analysis methods to earlier studies of designs based on vanadium alloy or low-activation martensitic steel, allowing direct comparisons. The very low short-term activation of silicon carbide results in an almost insignificant level of decay heat in postulated loss of coolant accidents, and a lower {gamma}-dose rate on the timescale of relevance to handling for maintenance operations. However on the longer time-scale, of interest in possible recycling operations, decommissioning and waste management, SiC/SiC appears to perform no better than vanadium alloy or low-activation martensitic steel, due in part to the activation of impurities in a realistic composition. ...

International Nuclear Information System (INIS)

Cross-sections for "8"4Sr(n, 2n)"8"3Sr, "8"6Sr(n, 2n)"8"5"mSr, "8"6Sr(n, 2n)"8"5Sr, "8"8Sr(n, 2n)"8"7"mSr, "8"4Sr(n, p)"8"4Rb, "8"6Sr(n, p)"8"6Rb, "8"8Sr(n, p)"8"8Rb and "8"8Sr(n, #alpha#)"8"5"mKr reactions have been measured at neutron energies from 13.5 to 14.6 MeV using activation technique and by means of #gamma#-ray spectrometry. The neutron flux was determined using the monitor reaction "9"3Nb(n, 2n)"9"2"mNb and the neutron energies were measured by the method of cross-section ratios for "9Zr(n, 2n)"8"9Zr to "9"3Nb (n, 2n)"9"2"mNb reactions. The results of present work are compared with data published previously.

International Nuclear Information System (INIS)

In this work, the half-lives of the beta-unstable nuclei "1"0"1Mo and "1"0"1Tc were studied using neutron-irradiated samples of "1"0"0Mo to produce "1"0"1Mo which in its turn generates "1"0"1Tc by beta decay. The gamma activity of each sample was followed for 5 consecutive half-lives in steps of 5 minutes. A total of 22 sources were measured and checked for dead-time influence, and the half-lives were obtained by weighted average. The results are statistically incompatible with the tabulated values.

Science.gov (United States)

The authors develop a procedure for the determination of the Al, Ti, V, Cu, Mn, Mo, and W content of nickel-base alloys by neutron activation analysis. An M-10 microtron with a beryllium target in a paraffin microtron (with a beryllium target) in a paraffin moderator served as the neutron source. In order to evaluate the procedure for quantitative analysis, the authors determined the contents of the above elements in five reference standards, the bulk density of which was 2.94-4.17 g/cm/sup 3/. The difference in the self-absorption of the gammaquanta was assessed by determining the number of gamma-quanta with energies in the range 60-1332 keV that had passed through the RS N4 and N8 which showed the greatest difference in their composition. The results of the determination are presented. The proposed procedure is simple and rapid and can be used to determine the alloying components of nickel-based ...

Energy Technology Data Exchange (ETDEWEB)

The {rvec n} + p {yields} d + {gamma} experiment under construction at LANSCE studies the weak interaction between neutrons and protons. The experiments will measure the directional dependence of the parity-violating {gamma}-ray asymmetry, A{sub {gamma}}, in the polarized cold neutron capture by para-hydrogen. The goal is to measure A{sub {gamma}} with uncertainty of 0.5 x 10{sup -8}, 10% of its predicted value. A{sub {gamma}} primarily isolates the {Delta}I = 1 component of the hadronic weak interaction and thus will determine the long-range weak pion-nucleon coupling constant H{sub {pi}}{sup 1}. The experiment is carefully designed for the LANSCE pulsed spallation neutron source to achieve the proposed statistical precision and to control systematic errors. We discuss the experiment and its status.

International Nuclear Information System (INIS)

The objective of the study is to measure the neutron cross sections for the "5"9 Co (n, 2n) "5"8 Co reaction around the 14 MeV energy region. Neutron activation cross section for almost all the nuclei, mostly in the medium energy region e.g., 7 to 20 MeV are reported in literature. Neutron cross section data around 14 MeV is of immense importance for the design of D + T fusion reactors. The accuracy of the cross section data at this energy region is a requirement for correct prediction of reactor parameters e.g., tritium breeding, nuclear heating, induced activity, etc. In order to perform the experiment, the Co-sample sandwiched in Ni foils was irradiated employing the J-25 Neutron Generator at the AERE, Savar, Dhaka. After irradiation, the counting was done by the activation technique using a high resolution Hp Ge ...

Energy Technology Data Exchange (ETDEWEB)

Neutron and gamma ray energy spectra were measured using an NE-213 scintillator at depths of 7.2, 15.2, and 22.2 cm in a tissue-equivalent phantom which was uniformly irradiated on one face by deuterium--tritium (DT) neutrons. Coupled neutron--gamma ray multigroup discrete-ordinates calculations were performed using semi-infinite slab geometry. These calculations were used to supplement the measured spectra below 1 MeV. Similar calculations were performed to study the perturbation in the phantom due to the detector. The measured and calculated spectra were used to determine the kerma distributions for neutrons and gamma rays at each location. The gamma radiation was determined to contribute more than 10% of the total dose at each depth. The calculated kerma also reveals that a knowledge of the gamma ray spectra below 1 ...

International Nuclear Information System (INIS)

State-of-the-art approaches for the calculation of gamma heating in LMFBR core, blanket and reflector regions have been evaluated, with particular emphasis on coupled neutron-gamma methods/cross section sets. The major source of calculational error was found to be the apparent failure to impose a mass-energy balance on total gamma energy yield from neutron capture and other interactions in the preparation of representative neutron-gamma cross section sets. The applicability of many simplifying assumptions was demonstrated, including: volume-weighted homogenization, insensitivity to the shape of the gamma-source-spectrum, gamma energy deposition equal to gamma energy source more than 10 cm inside large zones of uniform composition, and the negligible effect of bremsstrahlung. A simple one-group method was developed to ...

International Nuclear Information System (INIS)

Sodium is one of the most essential elements needed for metabolic processes amongst human beings. It is consumed in the form of sodium chloride but it is also present in edible plant leaves. Sodium is mostly analyzed by flame photometric method, a destructive and time consuming technique. Sodium has been determined in some green leave vegetables samples-palak, radish, khatta palak (ambat chuka), chaulai leaves, chauli bean covers and its seeds by instrumental neutron activation analysis. The method involves irradiation of samples with thermal neutrons from "2"4"1Am-Be source and counting "2"4Na activity (half life 15 hr) from the reaction "2"3Na(n,#gamma#) "2"4Na. Activity due to 1.37 MeV photopeak was counted with a NaI(Tl) crystal coupled to gamma ray spectrometer. Green leaves of the vegetables were thoroughly washed, dried at constant ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Theoretical assessment on the chromatographic {sup 99m}Tc generator preparation using (n, {gamma}) {sup 99}Mo produced ex-natural molybdenum was carried out. The relationship between the neutron flux for MoO{sub 3} target activation, Mo-content or Mo adsorption capacity of column packing material, {sup 99m}Tc pertechnetate concentration and/or {sup 99m}Tc radioactivity of eluate was established. The reasonably lower limit of neutron flux of reactor and Molybdenum content of column packing material were found out to estimate the production of portable chromatographic generators available for nuclear medicine application. The concentration of {sup 99m}Tc pertechnetate eluate of low {sup 99m}Tc concentration using the column elution technique was also evaluate theoretically and conducted successfully in practice. Three options of {sup 99m}Tc generator using Titanium-Molybdate, Zirconium-Molybdate and ...

Energy Technology Data Exchange (ETDEWEB)

A number of concrete culverts used to retrievably store drummed, dry, radioactive waste at the Savannah River Site (SRS), were suspected of containing ambiguous quantities of transuranic (TRU) nuclides. These culverts were assayed in place for Pu-239 content using thermal and fast neutron counting techniques. High resolution gamma-ray spectroscopy on 17 culverts, having neutron emission rates several times higher than expected, showed characteristic gamma-ray signatures of neutron emitters other than Pu-239 (e.g., Pu-238, Pu/Be, or Am/Be neutron sources). This study confirmed the Pu-239 content of the culverts with anomalous neutron rates and established limits on the Pu-239 mass in each of the 17 suspect culverts by in-field, non-intrusive gamma-ray measurements.

International Nuclear Information System (INIS)

Presented are the investigation results of electrophysical and physico-mechanical properties of KLF-20, Viksint U-4-21, Viksint KT-73, UF-7-21, KG-184, KL-4, KL-16SE-305, VIAT-1 and PPK-21 sealants, irradiated with sources of continuous and pulse #gamma#-radiation, as well as pulse #gamma#-neutron radiation. It is shown that electrophysical and physico-mechanical properties of sealants after irradiation by continuous #gamma#-radiation up to 10"6 doses and pulse gamma-neutron radiation with neutron fluence of 10"1"3 neutron/cm"2 and #gamma#-radiation dose of 10"4R do not practically change. Electric conductivity and tangent of the angle of dielectric losses increase in the process of irradiation. Electric conductivity depends on irradiation type, is proportional to dose rate and does not depend on temperature and pulse duration.

International Nuclear Information System (INIS)

A method and apparatus for nuclear borehole logging, and in particular, neutron porosity logging, uses a neutron source, and a pair of spaced lithium detectors, preferably Li"6I crystal or Li"6 doped glass, to detect neutrons emitted from a borehole formation being logged. The spectrum developed by the lithium detectors is processed to remove the gamma ray background radiation and the hydrogen absorption peak, thus allowing a more accurate neutron count. A Gaussian curve is fitted to the neutron peak of the spectrum, the curve eliminating the hydrogen absorption peak. The area under this Gaussian curve represents the neutron count. (author).

International Nuclear Information System (INIS)

The #gamma#-radiation following thermal neutron capture in "1"0"0Mo has been studied by singles and coincidence measurements. A "1"0"1Mo level scheme has been deduced and is compared with the results of previous (d,p), (n,#gamma#) and "1"0"1Nb decay studies. The existence of the first excited state at 13.51 keV has been confirmed. The present data yield a neutron binding energy of 5398.4 KeV. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

The detection limit of Instrumental Neutron Activation Analysis (INAA), about a few microgram per kg, is not sufficient to determine iridium concentrations in most geological samples. Use of the coincidence counting of the 316 and 468 keV gamma-rays emitted during the decay of {sup 192}Ir, improved the sensitivity (0.01 microgram per kg). The high iridium content of the clay layers from the Cretaceous-Tertiary transition (KTB) has been considered as an evidence of the extra-terrestrial origin of the KTB mass extinction. However some results indicate that a significant part of the iridium content in sediments has a volcanic origin. Radiochemical Neutron Activation Analysis (RNAA) in some KTB samples and in basic and ultra-basic rocks show that, unlike in volcanic products, no PGE (platinoids) fractionation appears in KTB samples. The nearby chondritic PGE pattern supports an ...

International Nuclear Information System (INIS)

Cross sections for (n,2n) (n,p) (n,#alpha#), and (n,d*)"1 reactions have been measured on ruthenium isotopes at the neutron energies of 13.5 to 14.8 MeV using the activation technique in combination with high-resolution gamma-ray spectroscopy. Data are reported for the following reactions: "1"0"4Ru(n,2n)"1"0"3Ru, "9"8Ru(n,2n)"9"7Ru, "9"6Ru(n,2n)"9"5Ru, "9"6Ru(n,p)"9"6Tc"g, "9"6Ru(n,p)"9"6Tc"m, "1"0"4Ru(n,p)"1"0"4Tc, "1"0"2Ru(n,p)"1"0"2Tc"m, "1"0"4Ru(n,#alpha#)"1"0"1Mo, "1"0"2Ru(n,#alpha#)"9"9Mo, "9"6Ru(n,#alpha#)"9"3Mo"m, and "9"6Ru(n,d*)"9"5Tc"m. Results were discussed and compared with the previous works.

Energy Technology Data Exchange (ETDEWEB)

Energy conservation and local energy deposition are investigated in the context of coupled-particle (i.e., neutrons, gamma rays, and charged particles) transport analysis. For charged particles, the concept of group splitting the 1 = 0 transfer matrix to ensure both particle and energy conservation is introduced. Although these procedures are more complex than those found in the usual neutron or coupled-neutron gamma-ray problem, they yield a consistent approach for the calculation of local energy deposition.

International Nuclear Information System (INIS)

(Jun 1972). United States Woolson, WA Las Vegas, Nev. 18 Jun 1972.

Energy Technology Data Exchange (ETDEWEB)

The X-ray properties of the main sequence Be stars conclude that they are a widely separated binary system containing an accreting neutron star.

Energy Technology Data Exchange (ETDEWEB)

The authors have developed a high-sensitivity real-time neutron radiography (NR) system by the use of the low power reactor of Kinki University. The system was constructed with a high efficiency neutron-photon converter, an image intensifier and a SIT TELEVISION camera. Some digital image processing techniques were applied for improving the quality of the real-time neutron images. By the use of this system, dynamic neutron imaging was performed successfully under the condition of a weak neutron field that was about two orders of magnitude lower than that of the standard NR system. The neutron flux, calculated from the fluctuation of the neutron response of the images, was nearly equal to the value measured by the foil activation method. From this fact, the efficiency for the neutron detection of the ...

Energy Technology Data Exchange (ETDEWEB)

A complete code based on the finite element method (FEM) is used to study the attenuation of gamma rays, of source energy 9 MeV, in simple homogeneous lead and water systems. The results are compared, in tables and graphs, with those produced by a Monte Carlo method of solution. In the comparison, particular attention is paid to the annihilation gamma rays generated by the pair production process, to energy deposition, and to the leakage spectra. A model, multilayer, slab shield, having a fission neutron source impinging on the left-hand face, is also solved by the FEM code, using data from a coupled neutron/gamma ray cross section library. The resulting neutron and gamma ray flux distributions, and the leakage spectra, are shown graphically. (author).

International Nuclear Information System (INIS)

The electromagnetic field due to an air explosion is here studied: neutron and the gamma-rays, generated by neutronic reactions, deposit energy which ionizes atmosphere; recoil electrons are also created by gamma collisions. This data set allows to solve the Maxwell equations which manage the electromagnetic field. The TRIPOLI-2 code studies the coupled neutron-gamma transport in 3D- geometries by the Monte Carlo method. The code has been modified to calculate the photon energy deposited in matter and the recoil electron current created by Compton effect. The method is tested wiht a simple case; then neutron and gamma transport is studied in air kerma, deposited photon energy, electron current are calculated as functions of space and time and the contributions of the different neutronic reactions are separately ...

International Nuclear Information System (INIS)

The High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory is one of the world's most powerful research reactors. In 1996, one year after the demise of the Advanced Neutron Source Project, the U.S. Department of Energy embarked on an aggressive program to upgrade the neutron scattering facilities at the HFIR. These upgrades, which are now in progress, include the installation of larger beam tubes, a high-performance hydrogen cold source, and additional neutron guides and neutron scattering instruments. An extensive analysis effort was performed over the past 4 yr to support the design of the modified beamlines and new user facilities and to assess the impact of the upgrades on the integrity of the existing reactor system. The results of three of these analyses are summarized here. Specifically, results are presented for analyses related to the design of the new cold ...

Energy Technology Data Exchange (ETDEWEB)

The dosimetry for radiotherapy involving neutrons is very complicated, owing to the complexity of secondary radiation components, whose contributions to the total absorbed dose have to be discriminated, owing to the different radiobiological effects. In order to separate thermal neutrons and photons, LiF dosimeters are mostly utilized. containing different percentage of Li, like as TLD-700, TLD-100 and TLD-600, but many problems arise. In the response of TLD-700 exposed to neutron-gamma mixed fields with high neutron flux, the contribution of thermal neutrons to the Tl emission is high. Moreover. TLD-100 and TLD-600 may undergo radiation damage, and great care has to be taken in order to obtain reliable results. Other TLDs showing lower sensitivity to neutrons are proposed and experimented for such high-flux neutron fields. The faced ...

Energy Technology Data Exchange (ETDEWEB)

The field of neutron imaging has a broad scope of applications and has played a pivotal role in visualizing and quantifying hydrogenous masses in metallic matrices. The field continues to expand into new applications with the installation of new neutron imaging facilities. In this scope, a neutron imaging facility for computed tomography and real-time neutron radiography is currently being developed around 2.0 MW TRIGA MARK-II Reactor at Maamora Nuclear Research Centre in Morocco (CENM). The neutron imaging facility consists of a neutron collimator, a real-time neutron imaging system and imaging process systems. In order to reduce the gamma-ray content in the neutron beam, the reactor tangential channel was selected. For power of 250 kW, the corresponding thermal neutron flux ...

Energy Technology Data Exchange (ETDEWEB)

The University of Virginia's real-time neutron radiography facility was characterized by measurement of the total neutron flux, gold/cadmium ratio, neutron/gamma ratio, and the effective collimar length-to-aperture diameter (L/D) ratio. The real-time neutron imaging system and collimator were further characterized by measuring the modulation transfer function (MTF) of the system. The collimator effectiveness was measured by using the MTF to determine the ''unparallelism'' of the neutron beam. The computer-based image processing system allowed rapid calculation of the MTF and the collimator effectiveness. The results of these measurements, using no collimator and a simple tube collimator, demonstrated the method's ability to determine the effective L/D ratio. The MTF measurement scheme provided a fast, reliable, and reproducible ...

Energy Technology Data Exchange (ETDEWEB)

The NPDGamma Experiment measures the parity-violating correlation A{sub {Gamma}Y} between neutron spin and photon momentum in the reaction {rvec n} + p {yields} d + {gamma}. Knowledge of A{sub {Gamma}Y} and other parity-violating observables in few-body nuclear systems will provide constraints for a parameterized description of {Delta}S = 0 parity-violating phenomena free from complications of nuclear structure. The NPDGamma experiment uses a polarized cold pulsed neutron beam, a liquid parahydrogen target, and a cylindrical array of 48 CsI(Tl) scintillation detectors operated in current mode to search for the asymmetry. NPDGamma recently completed the first phase of the program to measure A{sub {Gamma}Y} at the Los Alamos Neutron Science Center with the preliminary result A{sub {Gamma}Y} = (-1.2 {+-} 2.1(stat.) {+-} ...

Energy Technology Data Exchange (ETDEWEB)

The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,..cap alpha..), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,..gamma..) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide.

Energy Technology Data Exchange (ETDEWEB)

Ratio of the fissile isomers and prompt fissions yields has been measured in processes of neutron capture by /sup 241/Am and /sup 243/Am nuclei in the neutron energy interval from 0.2 up to 1.3 MeV. The present data and the previous results suggest that the fission Am isomers are spin structure isomers rather than shape isomers.

International Nuclear Information System (INIS)

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/#gamma# ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time #gamma# spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded #gamma# spectra created by the photopeak-Compton edge ...

Energy Technology Data Exchange (ETDEWEB)

High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPD Gamma experiment, a search for the small parity-violating {gamma}-ray asymmetry A{sub Y} in polarized cold neutron capture on parahydrogen, is one example. For the NPD Gamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared ...

UK PubMed Central (United Kingdom)

Interleukin 12 (IL-12) activates natural killer (NK) and T cells with the secondary synthesis and release of interferon-gamma (IFN-gamma) and other cytokines. IL-12-induced organ alterations are reported...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

We have carried out theoretical calculations for the production of the long-lived isomers {sup 93m}Nb({1/2}{sup {minus}}, 16y), {sup 121m}Sn(11/2{minus}, 55 yr), {sup 166m}Ho(7-, 1200 yr), {sup 184m}Re(8+, 165 d), {sup 186m}Re(8+, 2{times}10{sup 5} yr), {sup 178m}Hf(16+, 31 yr), {sup 179m}Hf(25/2-, 25 d), {sup 192m}Ir(9+, 241 yr), all of which pose potential radiation activation problems in nuclear fusion reactors. We consider (n, 2n), (n,n{prime}), and (n, {gamma}) production modes and compare our results both with experimental data (where available) and systematic. We also investigate the dependence of the isomeric cross section ratio on incident neutron energy for the isomers under consideration. The statistical Hauser-Feshbach plus preequilibrium code GNASH was used for the calculations. Where discrete state experimental information was lacking, rotational band members above the isomeric state, which can be justified ...

International Nuclear Information System (INIS)

A gel-type "9"9Mo-"9"9"mTc generator using Titanium-Molybdate target (TiMo-target) as column packing was developed in Radioisotope Department, the Dalat Nuclear Research Institute [1]. The concentration of trace elements in TiMo-target and radionuclidic purity in "9"9"mTc solution eluted from this type of generator were studied for quality control purpose. The monostandard method in neutron activation analysis has been applied to determine the concentration of trace impurities in titanium-molybdate target. For neutron activation analysis, TiMo samples were irradiated in the different channels of nuclear reactor IVV-9 at a neutron flux of maximum 2.1 x 10"1"3 n.cm"-"2s"-"1. The following chemical element impurities were determined: Na, W, Co, Fe, Zn, Ag, Sb and Cr. The gamma ray emitted nuclides found in "9"9"mTc solution eluted from our "9"9"mTc generator were ...

International Nuclear Information System (INIS)

(1974). Hungary Kolomit'sev, MA Ambardanashvili, TS Dundua, V.Yu. AN

Energy Technology Data Exchange (ETDEWEB)

The accurate prediction of local hot spot during normal operation is important to ensure core thermal margin in a very high temperature gas-cooled reactor because of production of its high temperature output. The active cooling of the reactor core determining local hot spot is strongly affected by core bypass flows through the inter-column gaps between graphite blocks and the cross gaps between two stacked fuel blocks. The bypass gap sizes vary during core life cycle by the thermal expansion at the elevated temperature and the shrinkage/swelling by fast neutron irradiation. This study is to investigate the impacts of the variation of bypass gaps during core life cycle as well as core restraint mechanism on the amount of bypass flow and thus maximum fuel temperature. The core thermo fluid analysis is performed using the GAMMA+ code for the PMR200 block-core design. For the analysis not only are some modeling features, ...

International Nuclear Information System (INIS)

We have measured the neutron capture and fission cross section of "2"3"3U at the neutron time-of-flight facility n-TOF at CERN in the energy range from 1 eV to 1 MeV with high accuracy by using a high performance 4#pi# BaF_2 Total Absorption Calorimeter (TAC) as a detection device. The method, based on the shape analysis of the TAC energy response, allowing to disentangle between #gamma#'s originating from fission and capture will be presented as well as the first very preliminary results. (authors)

CERN Document Server

2009 has been an extraordinary year for gamma-ray pulsar astronomy and 2010 promises to be equally good. Not only have we registered an extraordinary increase in the number of pulsars detected in gamma rays, but we have also witnessed the birth of new sub-families: first of all, the radio-quiet gamma pulsars and later an ever growing number of millisecond pulsars, a real surprise. We started with a sample of 7 gamma-ray emitting neutron stars (6 radio pulsars and Geminga) and now the Fermi-LAT harvest encompasses 24 "Geminga-like" new gamma-ray pulsars, a dozen millisecond pulsars and about thirty radio pulsars. Moreover, radio searches targeted to LAT unidentified sources yielded 18 new radio millisecond pulsars, several of which have been already detected also in gamma rays. Thus, currently the family of gamma-ray ...

International Nuclear Information System (INIS)

The introduction prior to series of papers on the application of neutrons for materials science (MS) in this issue starts with a brief summary of neutron scattering research history in Japan; from the individual activity by Motoharu Kimura at RIKEN early around 1940s to those at present era of world leading neutron science facilities of both JRR3 research reactor and JPARC of the largest proton Accelerator complex in Tokai. Then physical properties of low energy neutrons applied to MS as well as such neutron sources are also reviewed (http://www.jstage.jst.go.jp/browse/jvsj2). (author)

Science.gov (United States)

The experimental work completed thus far in the areas of rapid radiochemical separations and metastable isomeric states is summarized. Activation analyses were made in samples of ore materials and metals using rapid radiochemical separations to isolate short-lived radioactive isotopes such as 3.77-min V/sup 52/ and 14.6-min Mo/sup 101/. The analytical results obtained were compared to the results obtained from standard chemical and instrumental analytical methods and, where possible, to activation analysis results obtained from longer-lived isotopes of the same element. Further work is in progress to improve the procedures, to evaluate the reproducibility and accuracy of the methods, and to evaluate their usefulness on a wide variety of sample matrices. The research on short-lived metastable isomers showed that 1.7-min W/sup 185m/ is not produced in sufficiently high yield for the development of a supplementary ...

International Nuclear Information System (INIS)

Instrumental neutron activation analysis is used for simultaneously determination of macrocomponents in ferroelectric materials LLZT. Pb, Zr, Ti have been determined by "2"0"3Pb, "8"9Zr and "4"8Sc nuclides created by fast neutron (14.5 MeV) activation. Application of paraffine as neutron moderator and reflector allows to simultaneously determine lanthanum by "1"4"0La nuclide. It has been shown that zirconium, titanium and lanthanum can be determined with the accuracy of #+-#0.1 mas. % and lead - #+-#0.7 mas. %.

Energy Technology Data Exchange (ETDEWEB)

By using this doping method, silicon semiconductors with extremely uniform dopant distributions can be produced, and this is the dominant advantage of NTD compared with a conventional chemical doping. Good uniformity of a dopant concentration is usually required for high power applications such as thyristor (SCR), IGBT, IGCT and GTO and for special sensors. Achieving an accurate neutron fluence corresponding to a target resistivity as well as a uniform irradiation is the prime target of a neutron irradiation for NTD. Generally, in order to reach an accurate neutron fluence, a real time neutron flux is monitored by a neutron detector such as a Self-powered Neutron Detector(SPND). And, after an irradiation, the total irradiation fluence is confirmed by measuring the absolute activity of a neutron ...

Energy Technology Data Exchange (ETDEWEB)

A 16 l liquid parahydrogen target has been developed for a measurement of the parity-violating {gamma}-asymmetry in the capture of polarized cold neutrons on protons in the {rvec n} + p {yields} d + {gamma} reaction by the NPDGamma collaboration. The target system was carefully designed to meet the stringent requirements on systematic effects for the experiment and also to satisfy hydrogen safety requirements. The target was designed to preserve the neutron polarization during neutron scattering on liquid hydrogen (LH{sub 2}), optimize the statistical sensitivity to the {rvec n} + p {yields} d + {gamma} reaction, minimize backgrounds coming from neutron interaction with the beam windows of the target cryostat, minimize LH{sub 2} density fluctuations which can introduce extra noise in the gamma asymmetry signal, and ...

Energy Technology Data Exchange (ETDEWEB)

The thermal neutron column of the JRR-2 reactor was remodelled in order to install a medical irradiation facility. The design experience and the cource of this remodelling are presented. At first, the thermal neutron flux was lower than expected, and the expected radiation condition was achieved by the following improvements: (1) removal of graphite from the thermal neutron column to increase the neutron flux, (2) twice increase of bismuth shielding and the shift of its position to improve the shielding effect against gamma ray, (3) application of B{sub 4}C rubber on the both surfaces of the shielding door to suppress the secondary gamma ray generation from the structural materials, (4) LiF tiles are applied on the inner face of the neutron beam exit hole to suppress the secondary gamma ray from the beam exit, and (5) ...

International Nuclear Information System (INIS)

The Polarized Gamma-ray Observer (PoGOLite) is a balloon-borne instrument that will measure gamma-ray polarization in the energy range 25-80 keV from astronomical sources such as pulsars, accretion discs and jets from active galactic nuclei. The two additional parameters provided by such observations, polarization angle and degree, will allow these objects to be studied in a new way, providing information about their emission mechanisms and geometries. The instrument measures azimuthal scattering angles of photons within a close packed array of phoswich detector cells (PDCs) based on coincident detection of Compton scattering and photoelectric absorption. Each PDC comprises three different scintillating components and combines photon detection, active collimation and bottom anticoincidence into one single unit. The three parts are viewed by a photomultiplier tube (PMT) and pulse shape discrimination is ...

Energy Technology Data Exchange (ETDEWEB)

An experimental study of the {sup 241}Am incineration in a high-intensity thermal neutron flux was carried out at the high-flux reactor of the Institut Laue-Langevin in Grenoble. The combination of nuclear {gamma}-ray spectroscopy and off-line mass spectrometry methods made possible the measurement of several parameters of the transmutation chain and the first experimental determination of the unknown {sup 242gs}Am thermal neutron capture cross section, which plays an essential role in the {sup 241}Am incineration process. During a 19 days irradiation in a thermal neutron flux of 5.6x10{sup 14} n/(s cm{sup 2}), (46{+-}5)% of the initial {sup 241}Am was transmuted by neutron capture of which (22{+-}8)% was incinerated by nuclear fission. A value of the thermal neutron cross section of {sup 242gs}Am(n,{gamma}) of (330{+-}50) barns was ...

International Nuclear Information System (INIS)

The neutron capture cross sections of the stable molybdenum isotopes have been measured with high energy resolution (#DELTA#E/E < approximately 0.2%), between 3 and 90 keV neutron energy, at the 40 m station of ORELA. Average resonance parameters are extracted for s- and p-wave resonances. The s-wave neutron strength function is close to 0.5x10"-"4 for all isotopes, but the p-wave strength function exhibits a well defined peak near A approximately 95. Both s- and p-wave radiative widths decrease markedly as further neutrons are added to the closed shell. The p-wave radiative widths are generally greater than the s-wave widths showing the presence of non-statistical #gamma#-decay mechanisms. Valence neutron theory fails to explain the magnitude of the p- to s-wave radiative width disparity and doorway state processes are invoked. In particular, the data for ...

Energy Technology Data Exchange (ETDEWEB)

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in ...

Energy Technology Data Exchange (ETDEWEB)

A brief overview if provided of selected reports presented at the International Symposium on Molecular Mechanisms of Radiation- and Chemical Carcinogen-Induced Cell Transformation held at Mackinac Island, Michigan on September 19-23, 1993.

Energy Technology Data Exchange (ETDEWEB)

We present theoretical calculations for the production of the long-lived isomers: {sup 121m}Sn (11/2-, 55 yr), {sup 166m}Ho(7-, 1200 yr), {sup 184m}Re(8+, 165 d), {sup 186m}Re(8+, 2{times}10{sup 5} yr), {sup 178m}Hf(16+, 31 yr), {sup 179m}Hf(25/2-, 25 d), {sup 192m}Ir(9+, 241 yr), all which pose potential radiation activation problems in nuclear fusion reactors if produced in 14-MeV neutron-induced reactions. We consider mainly (n,2n) production modes, but also (n,n{sup {prime}}) and (n,{gamma}) where necessary, and compare our results both with experimental data (where available) and systematics. We also investigate the dependence of the isomeric cross section ratio on incident neutron energy for the isomers under consideration. The statistical Hauser-Feshbach plus preequilibrium code GNASH was used for the calculations. Where discrete state experimental information was lacking, rotational band members ...

International Nuclear Information System (INIS)

IRAN.LIB is a Coupled Neutron-Gamma library which was developed to be used by the ANISN/PC (ccc-0514/02). The library was developed mainly for shielding calculations and it contains 33 elements mostly used as shielding materials, such as concrete. IRAN.LIB is a set of six libraries, each having the same elements but different number of energy groups. In order to use IRAN.LIB by ANISN/PC, this code must be modified. (author).

Energy Technology Data Exchange (ETDEWEB)

The weak interaction between neutrons and protons has never been resolved experimentally. In analogy with the strong NN interaction, the weak NN interaction at low energy can be parametrized in terms of a meson exchange model with parity violating meson-nucleon couplings. Unlike the measured proton-proton weak interaction, the neutron-proton weak interaction is sensitive to the weak pion-nucleon coupling constant H{sub {pi}}{sup 1}. This coupling, which is responsible for the longest-ranged part of the weak NN interaction and is therefore an essential part of any description of weak interactions in nuclei, remains undetermined despite many years of effort. A measurement of the gamma ray directional asymmetry A{sub {gamma}} in the capture of polarized neutrons by parahydrogen has been proposed at Los Alamos National Laboratory. The goal of this experiment is to determine A{sub ...

International Nuclear Information System (INIS)

We have done analysis of elements in the Baltic sea sediment by using gamma spectrometry in neutron activation analysis Goal of the analysis is to determine the rate of morsel elements which is contained in the Baltic sea sediment. Sample of the Baltic sea Sediment (IAEA-SED-1), Standard of Reference Material (SRM) 1646 Estuarine Sediment and Standard Ce, Fe, Sc, and Co are put into vial of capsule rabbit, then irradiated together for 30 minutes in rabbit facility Multi Purpose Reactor at power of 25 MW and then cooled for one week. Next sample, standard, and SRM which have irradiated, each is cut for 30 minutes using gamma spectrometer. Result of analysis of rate of elements Ce, Fe, Sc and Co in the baltic sea sediment successively equal to 141.20 ppm, 5.91 %, 14.88 ppm, and 19.59 ppm. Result of analysis in SRM Estuarine sediment successively equal to 96.60 ppm, 3.21 %, 10.25 ppm, and 9.63 ppm. Result ...

Energy Technology Data Exchange (ETDEWEB)

The neutron detector is cased in a metal envelop and has one detector with a very sensitive fission chamber and a second detector with a fission chamber less sensitive that the first one and a boron coated ionisation chamber for reducing gamma radiation detection.

Energy Technology Data Exchange (ETDEWEB)

We present the results of modeling intended to evaluate the feasibility of using neutrons from induced fission in highly enriched uranium (HEU) as a means of detecting clandestine HEU, even when it is embedded in absorbing surroundings, such as commercial cargo. We characterized radiation from induced fission in HEU, which consisted of delayed neutrons at all energies and prompt neutrons at energies above a threshold. We found that for the candidate detector and for the conditions we considered, a distinctive HEU signature should be detectable, given sufficient detector size, and should be robust over a range of cargo content. In the modeled scenario, an intense neutron source was used to induce fissions in a spherical shell of HEU. To absorb, scatter, and moderate the neutrons, we place one layer of simulated cargo between the source and target and an identical layer between the ...

International Nuclear Information System (INIS)

We conducted (n, #gamma#) and (d, p) reactions leading to "8"7", "8"8", "8"9"Sr in addition to "8"8Sr (d, t) "8"7Sr and 24 keV neutron capture in "8"8Sr. (orig./HSI).

International Nuclear Information System (INIS)

Full text: Semiconductor detectors coated with boron or lithium compounds have been studied for neutron detection for decades but, until recently, have been limited to thermal neutron detection efficiencies of less than 5%. We reported previously on development and simulation studies of perforated detectors whose perforations are filled with neutron-reactive material in order to produce higher detection efficiencies. Incorporation of bare and cadmium-backed detectors into battery-powered devices with low-power electronics enables us to produce compact personal neutron dosimeters that provide LED readout of counts, which can be related approximately to neutron dose. We report here on experimental studies with such compact devices; devices capable of direct readout in dose units are anticipated. The thermal and epithermal neutron flux densities from the tangential ...

Energy Technology Data Exchange (ETDEWEB)

Neutron capture ..gamma..-ray spectra have been measured at 11 average neutron energies from 10 to 530 keV in /sup 88/Sr using a 20 x 15 cm NaI detector with time-of-flight discrimination of background events. The partial radiation widths and the calculated partial valence widths are compared for the strong p-wave resonances at 287 and 321 keV and found to be highly correlated. At these energies, the spectra are dominated by strong transitions to low-lying single particle states, in confirmation of the role of valence capture in the 3p region. However, the data do not support this mechanism at <508> keV.

UK PubMed Central (United Kingdom)

Gamma interferon plays an important role in regulating the functional properties of mononuclear phagocytes. In the present study, the role of activated protein kinases in the mechanism of action of...Full Text Available

International Nuclear Information System (INIS)

The status of neutron activation cross sections for some threshold reactions important for reactor materials dosimetry is reviewed. An attempt is made to understand and explain discrepancies between integral and differential data, using recent available experimental results. The importance of standard and benchmark neutron fields for testing differential data for reactor dosimetry is emphasized and the Interlaboratory Reaction Rate (ILRR) program, as well as a similar program pursued by the IAEA, are briefly described.

Science.gov (United States)

The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the ...

Energy Technology Data Exchange (ETDEWEB)

Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was used to determine the concentrations of As, Ca, Co, Cr, Cu, Eu, Fe, K, La, Mg, Mn, Mo, Na, Pr, Sb, Se, Th, U, V and Z, in 82 leaf samples belonging to two cultivars of pigeonpea (Cajanus cajan (L.) Millsp). Pigeonpea, an easy cultivation legume species, probably originated from Africa and adapted to brazilian conditions, is a very promising and unconventional source of food, mainly to the grain production intended for human feeding, and that even can be used in flour products. It is an excellent proteic supplement for ruminants, due to its large potential of forage production and its high nutritive value, or in addition it can be used in the recuperation of exhausting soils either by means of its utilization as green manure or by taking free Nitrogen from the atmosphere to produce nitrates which can be utilized by the plants. However, in ...

Energy Technology Data Exchange (ETDEWEB)

An analyser for detecting explosives has at least one neutron source and a plurality of gamma ray detectors. An article to be analysed is moved adjacent the source and detectors and is subjected to neutrons which generate gamma rays from any nitrogen in the article. The gamma rays are detected and analysed to determine the nitrogen concentration within the article. In order to achieve an area of uniform detection there are a plurality of detectors equidistant both from the or each source and from the article to be analysed. In order to avoid a decrease in sensitivity away from the source(s) and detectors there may be a second opposing array of source(s) and detectors on the opposite side of the article. For greatest uniformity of detection, a source in one array opposes a detector in the other array and vice versa. Transmission of radiation from the analyser is kept at safe levels ...

Energy Technology Data Exchange (ETDEWEB)

For heavy-ion beam driven inertial fusion ''liquid-protected'' reactor designs such as HYLIFE-II, a mixture of molten salts made of F{sup 10}, Li{sup -6}, Li{sup 7} and Be{sup 9} (called flibe) allows small chambers and final-focus magnets closer to the target with superconducting coils suffering higher radiation damage, though they can stand only a certain amount of energy deposited before quenching. This work has been primarily focusing on verifying that total energy deposited by fusion neutrons and induced gamma rays remain under such limit values and the final purpose is the optimization of the shielding of the magnetic lens system from the points of view of the geometrical configuration and of the physical nature of the materials adopted. The system is analyzed in terms of six geometrical models going from simplified up to much more realistic representations of a system of 192 beam lines, each focused by ...

Energy Technology Data Exchange (ETDEWEB)

Some crops of important nutritive requirements have been collected from farmlands located in Bitsichi an old tin mining town in north central region of Nigeria. The food crops were analyzed in order to determine trace element concentrations level using Neutron Activation Analysis (NAA). The activity concentrations due to natural radionuclides in the food samples and soil samples collected within the root zone of the crops were also determined using gamma-ray spectrometry (GRS). The NAA results obtained showed higher concentration of Potassium among the essential elements in all the crops. Calcium concentration in both maize and Guinea corn was below detection limit and also Zn in Green beans, sweet potato and cassava. The trace elements; Sc, Hf, Sm, and Th, were below detection limit in all the crops except in Green beans. Rubidium (Rb) and lanthanum (La) were below detection limits only in Cabbage. The ...

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the major activities and accomplishments of the Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Radiotherapy Research Program for calendar year 2001. Applications of supportive research and development, as well as technology deployment in the fields of chemistry, radiation physics and dosimetry, and neutron source design and demonstration are described. Contributions in the fields of physics and biophysics include development of advanced patient treatment planning software, feasibility studies of accelerator neutron source technology for Neutron Capture Therapy (NCT), and completion of major modifications to the research reactor at Washington State University to produce an epithermal-neutron beam for NCT research applications.

International Nuclear Information System (INIS)

We have developed a new type personal dosemeter by using a B-10 doped silicon p-n junction detector with a polyethylene radiator and a polyethylene moderator. The purpose of this study was to develop a real time neutron dosemeter with a nearly flat response in the energy range from thermal to 15 MeV and low angular dependence to the incident neutron direction. The neutron response of the dosemeter was obtained with the Monte Carlo calculation and the monoenergetic neutron experiment in a free air field and also under a condition attached on a phantom.

Energy Technology Data Exchange (ETDEWEB)

The neutron capture cross-section of {sup 234}U has been measured for energies from thermal up to the keV region in the neutron time-of-flight facility n-TOF, based on a spallation source located at CERN. A 4{pi} BaF{sub 2} array composed of 40 crystals, placed at a distance of 184.9 m from the neutron source, was employed as a total absorption calorimeter (TAC) for detection of the prompt {gamma}-ray cascade from capture events in the sample. This text describes the experimental setup, all necessary steps followed during the data analysis procedure. Results are presented in the form of R-matrix resonance parameters from fits with the SAMMY code and compared to the evaluated data of Endf in the relevant energy region, indicating the good performance of the n-TOF facility and the TAC. (authors)

International Nuclear Information System (INIS)

A computer-based beam dosimetry measurement system for boron neutron capture therapy provides accurate, sensitive, and rapid readout and recording of all beam dose components, epithermal and thermal neutron flux, and gamma-ray dose rate. This dosimetric system includes input from the characterization of the epithermal neutron beam developed at the Massachusetts Institute of Technology, actual BPA pharmacokinetic data from a specific human subject being irradiated, output of MacNCTPLAN, a treatment planning system developed by the authors group, and input from the five on-line beam detectors. The purpose of this system and associated readout systems is to ensure that the desired dose is delivered to the subject within acceptable dose tolerances, e.g., #+-#5% of the target dose, and that any perturbations in the neutron beam that may occur during irradiation can be rapidly evaluated ...

International Nuclear Information System (INIS)

Neutron resonance interactions with "1"0"0Mo were studied at a time-of-flight facility. The transmission of two oxide samples (97.4% "1"0"0Mo) was measured at a 78.20 m flight path and the neutron capture cross section was measured at 40.12 m. Resonance analyses yielded parameters of 124 resonances. Capture #gamma#-ray spectra from 11 resolved resonances were measured with a Ge(Li) detector at a 10.45 m flight path. In contrast to neighboring nuclei, partial radiation widths of strong p-wave resonances are not in agreement with valence model predictions.

International Nuclear Information System (INIS)

Low-lying nuclear energy levels in "1"1"0In and "1"1"2In were determined from de-excitation #gamma#-rays produced with "1"0"7Ag(#alpha#,n#gamma#)-"1"1"0In, "1"0"8Pd("6Li,4n#gamma#)"1"1"0In, "1"0"9Ag(#alpha#,n#gamma#)"1"1"2In and "1"1"0Pd("6Li,4n#gamma#)"1"1"2In reactions. In addition, the "1"1"4In energy level structure was investigated with the "1"1"0Pd("7Li,3n#gamma#)"1"1"4In reaction. Properties of de-excitation #gamma#-rays were determined from #gamma#-#gamma# coincidence, excitation, and angular distribution measurements conducted with Ge(Li) and Ge(intr.) #gamma#-ray detectors. A sequence of intraconnected levels in each of "1"1"0,"1"1"2,"1"1"4In were assigned to the (#pi#g"-"1/sub 9/2/, #nu#h/sub 11/2/) configuration. For the "1"1"0,"1"1"2,"1"1"4In energy level schemes a model calculation has ...

International Nuclear Information System (INIS)

A new software for neutron activation analysis was designed, built and implemented on a desktop computer using Visual Basic 6.0 program. The construction of this data analyzer computer program is described. The new software deals with peak reports resulting from Gammaplus software with minimum interference from the user in order to save time, manpower and minimize human errors. Its ability to find the concentrations of chemical elements within samples is proven to be fast, reliable and user friendly. (author)

International Nuclear Information System (INIS)

This paper presents the results obtained in the gamma scanning of two fuel pins from the bent subassembly of the fast breeder test reactor (FBTR) using a segmented gamma scanning system employing segment correlation developed for the assay of glove box solid waste. In addition to the actinide profiles, the paper also discusses the fission products and clad activation product profiles and tries to correlate the experimental values of the latter with computed values. (author). 4 refs., 1 fig., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to ...

Energy Technology Data Exchange (ETDEWEB)

Applying a total energy absorption {gamma}-ray detector composed of 12 bricks (5x5 cm{sup 2}, 7.5 cm thick) of Bi{sub 4}Ge{sub 3}O{sub 12}(BGO) scintillators, the absolute measurement of capture cross sections for Au and Sb has been made in an energy region between 0.01 eV and 10 eV using the linac time-of-flight method. Incident thermal neutron flux was absolutely determined by using the BGO detection system with a Sm sample. To extend the neutron flux measurement from the thermal neutron region to higher neutron energy, the {sup 10}B(n, {alpha} {gamma}) reaction was applied. Absolute capture yield for the relevant capture sample was obtained by the saturated capture yield at a large resonance of the sample. Gold was selected to investigate the application of the BGO detection system to the absolute measurement of the capture cross sections, since the {sup ...

International Nuclear Information System (INIS)

Shielding calculations for neutron-gamma radiation are usually done by using the full Theory of Transport or the Monte Carlo Techniques. After some works based on the Albedo Method, the shielding calculations for neutron-gamma radiation have a reliable tool with great didactical value which shows its clarity and simplicity for the resolution of cases that involve neutrons and photon shielding in nonmultiplying media. The excellent results of these works have motivated the elaboration and the development of this study that will be presented in this dissertation. The balance of a neutronic current entering a shield of two layers considering the coupling neutron-gamma will be determined by the Albedo Method. The shield will be composed of a layer of iron and another one of manganese with 10 cm of thickness each. The arrays of the materials coefficients will be obtained from the ANISN ...

International Nuclear Information System (INIS)

The Cs-137 radioactivity of a neutron-irradiated nuclear fuel sample has been measured by means of a micro-gamma scanning system which is associated with a high purity Ge detector. Subsequently the burn-up has been calculated from the Cs-137 radioactivity data and then compared with the values from the theoretical computation and chemical anaylsis. The burn-up value obtained with the gamma-scanning system seems to be reasonably agreeable with that of the chemical anaylsis provided that the statistical error in the experiments is taken into account. It is revealed that the burn-up data from the theoretical approach is slightly higher than those of micro-gamma scanning and chemical analysis methods. (Author).

International Nuclear Information System (INIS)

The modeling methods used to compute the neutron-induced activation of target and near-target materials in the NIF facility are presented. A detailed space and energy description of the neutron environment in the different materials is provided. A new capability has been developed to treat in a general way the activation of debris produced in an operational regime of yield and no-yield experiments. First calculations are addressed to analyze the activity of the debris into the target chamber. The contribution of the different components to activity, interior dose rates, and waste disposal rating (WDR) is determined. The importance of the activation coming from primary irradiation in the target, and from secondary irradiation in debris deposited onto the first wall is assessed. Finally, waste hazards of the activated ...

International Nuclear Information System (INIS)

Prompt fission neutron energy spectra for "2"3"5U and "2"3"9Pu have been measured for fission neutron energies greater than the energy of the incident neutrons inducing fission. The measurements were undertaken to investigate the shape dependence of the fission neutron spectra upon both the incident neutron energy and the mass of the nucleus undergoing fission. Measurements were made for both nuclides at incident neutron energies of 0.50, 1.50, 2.50 and 3.50 MeV. The data are presented either as relative yields or as ratios of measured spectra to that of "2"3"5U at 0.50 MeV. Incident neutrons were produced by the "7Li(p,n)"7Be reaction using a pulsed, bunched proton beam from the 5.5 MV Van de Graaff accelerator at the University of Massachusetts Lowell Radiation Laboratory. Fission neutrons were detected by a thin ...

International Nuclear Information System (INIS)

In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at CEA/DSM with objectives to determine optimal conditions for transmutation and incineration of minor actinides (MA) in high intensity neutron fluxes. Our experimental tools based on alpha- and gamma-spectroscopy of the samples and the development of micro fission chambers could gather either microscopic information on nuclear reactions (total or partial cross sections for neutron capture and/or fission reactions) or macroscopic information on transmutation and incineration potentials. Neutron capture cross sections of selected actinides ("2"4"1Am, "2"4"2Am, "2"4"2Pu, "2"3"7Np) have already been measured at ILL, showing some discrepancies when compared to evaluated data libraries but in overall good agreement with recent data. The studies and possibilities offer by the MEGAPIE project to assess ...

Energy Technology Data Exchange (ETDEWEB)

The neutron transmutation doping (NTD) method was applied to the initially p-type silicon in order to extend the NTD applications at HANARO. The relationship between the irradiation neutron fluence and the final resistivity of the initially p-type silicon material was investigated. The proportional constant between the neutron fluence and the resistivity was determined to be 2.3473x10{sup 19} n {omega} cm{sup -1}. The deviation of the final resistivity from the target for almost all the irradiation results of the initially p-type silicon ingots was at a range from -5% to 2%. In addition, the burn-up effect of the boron impurities, the residual {sup 32}P activity and the effect of the compensation characteristics for the initially p-type silicon were studied. Conclusively, the practical methodology to perform the neutron transmutation doping of the initially p-type silicon ingot was ...

International Nuclear Information System (INIS)

We describe in a comprehensive fashion the Los Alamos second-generation system for passive and active neutron assays of drum-size containers. The developmental history of this 7-year project is presented with emphasis on the pulsed active neutron technique (differential dieaway), which has achieved milligram levels of assay sensitivity for both plutonium and uranium wastes. We describe in detail the matrix effects for both passive and active neutron assays. We present in a thorough fashion our novel approach to achieving comprehensive corrections for these matrix effects using measurements made during the assays. We develop a matrix correction formalism based on separate neutron absorption and moderator indices determined from these measurements. These are presented as a series of analytic functions fitted to the data. Absolute calibrations ...

International Nuclear Information System (INIS)

The #gamma#-ray spectrum emitted after thermal neutron capture in "8"7Sr was studied at the ILL high flux reactor with pair- and intrinsic Ge-spectrometers. 661 transitions were assigned to the reaction "8"7Sr(n,#gamma#)"8"8Sr and 205 of them were placed into a "8"8Sr level scheme of 47 levels. This represents 88% of the observed intensity. The level energies were determined with a precision of better than 22 ppm; the neutron binding energy was determined as 11 112.69 (22) keV. To aid the analysis high resolution particle spectra of the reaction "8"7Sr(d,p)"8"8Sr were measured at 20 MeV deuteron energy with the Munich Q3D spectrometer. 85 states were observed with this reaction. The data helped to establish newly found levels and to differentiate between primary and secondary transitions in the (n,#gamma#) data. The observed level densities and primary transition strengths are ...

Energy Technology Data Exchange (ETDEWEB)

The flux of cosmic ray antiprotons with kinetic energies between /approximately/1 and 15 GeV is /approximately/5 times greater than the flux predicted on the basis of the leaky-box model. This excess is attributed to secondary antineutron production in compact sources. Because the antineutrons are not confined by the magnetic field of the compact source, they leave the interaction site, decay in interstellar space and account for the apparent excess cosmic ray antiproton flux. The escape and decay of neutrons produced in association with the antineutrons is a source of cosmic ray protons. Observations of the angular variation of the intensity and spectral shape of 100 MeV ..gamma..-rays produced by neutron-decay protons in the reaction p + p ..-->.. ..pi../sup 0/ ..-->.. 2..gamma.. could reveal compact-source cosmic ray production sites. COS-B observations of spectral hardening near point sources, ...

International Nuclear Information System (INIS)

This paper consists the radiation streaming analysis of Horizontal Flux Unit (HFU) penetrations in Calandria Vault of 540 MWe PHWR. There are total 7 HFU penetrations on west wall of calandria vault. As these penetrations are in accessible area, a detailed analysis has been carried out to find the neutron and gamma dose rates around these penetrations when reactor is operating. Analysis has been carried out Using the computer code MCNP and DOT-III. Based on the predictions at HFU penetrations, shielding arrangement was recommended. Neutron and gamma dose rate higher than estimated were observed at TAPS-4. This was because of installed shield not being similar to recommended one due to site conditions. Subsequently semi-empirical calculations using measured data were carried out by MCNP to further augment the existing shield taking into consideration the space limitations at site. (author)

Energy Technology Data Exchange (ETDEWEB)

The mass and charge distributions in an unseparated mix of fission product nuclei from thermal-neutron fission of /sup 242m/Am were studied through semiconductor gamma-ray spectrometry. Samples of the fissionable material under study were irradiated in a vertical irradiation tube of the MIFI IRT research reactor. Following irradiation, measurements were made on aperture-calibrated semiconductor detectors. For broader identification of fission fragment nuclides three experiments were conducted that differed substantially in irradiation duration. The spectrum of gamma radiation from the mix of fission products and the time dependences of count rate at total absorption peaks were analyzed on SM-4 and Iskra-226 computers. The values of yields obtained were compared with data of investigations conducted earlier with other experimental methods, and also with the results of calculations.

Energy Technology Data Exchange (ETDEWEB)

Neutron capture cross sections of actinides are of great relevance for the Transmutation of Nuclear Waste in Accelerator Driven Systems (ADS) and Generation-IV reactors. The neutron capture cross sections of {sup 237}Np and {sup 240}Pu in the range of 1 eV to 2 keV were measured at the n-TOF facility with a Total Absorption Calorimeter. The data have been analyzed with the SAMMY code. The corresponding covariance matrices have been generated. The final cross sections are presented and compared to the previously existing ones.The n-TOF {sup 237}Np {sigma}(n,{gamma}) is in agreement with the evaluated data files below 300 eV and its is lower by 10 to 15% up to 2 keV. This discrepancy with the evaluated data files is also observed in the capture cross section derived from the transmission measurements of Gressier et al. In the case of the {sup 240}Pu {sigma}(n,{gamma}), the n-TOF ...

Energy Technology Data Exchange (ETDEWEB)

High energy physics facilities must monitor the radiation doses received by their personnel. This monitoring can only be effective if the radiation detection devices can be calibrated with a good degree of accuracy. Radiation fields are usually composed of several types of radiation, including gamma rays, beta radiation, neutrons, etc. The neutron detection instruments respond not only to the neutrons coming directly from the source but also those scattered from the floor, walls, and ceiling. The amount of neutron scattering varies from site to site depending on the construction materials and layout of the building. The purpose of this study was to determine the scattered neutron fraction in the central volume of the calibration mezzanine of the Radiation Physics Calibration Facility (RPCF) at the Fermi National Accelerator Laboratory (Fermilab). At Fermilab, ...

International Nuclear Information System (INIS)

We examined the effect of the trophic protein, nerve growth factor (NGF), on cultures of fetal rat neostriatum and basal forebrain-medial septal area (BF-MS) to define its role in brain development. Treatment of cultures with NGF resulted in an increase in the specific activity of the cholinergic enzyme choline acetyltransferase (CAT) in both brain areas. CAT was immunocytochemically localized to neurons. In the BF-MS, NGF treatment elicited a marked increase in staining intensity and an apparent increase in the number of CAT-positive neurons. Moreover, treatment of BF-MS cultures with NGF increased the activity of acetylcholinesterase, suggesting that the cholinergic neuron as a whole was affected. To begin defining mechanisms of action of NGF in the BF-MS, we detected NGF receptors by two independent methods. Receptors were localized to two different cellular populations: neuron-like cells, and non-neuron-like cells. Dissociation studies with ...

Energy Technology Data Exchange (ETDEWEB)

Red mud, and red mud activated by dissolution in hydrochloric acid and reprecipitation with ammonia, were tested as catalysts for the hydrogenation of an anthracene oil in a trickle-bed reactor. Conversion data were determined for the different polyaromatic compounds in the anthracene oil. Red mud shows appreciable catalytic activity, which is enhanced by the activation. Although both red mud and activated red mud are less active than a commercial Ni-Mo/[gamma]-alumina hydrotreating catalyst, the difference in activity is smaller when conversion to hydroaromatics instead of total conversion of reactants is considered. 20 refs., 8 figs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

A three-dimensional, continuous-energy, coupled neutron-gamma Monte Carlo model of the advanced neutron source (ANS) final preconceptual reference core design has been developed using MCNP Version 3b. This model contains the reactor core with control rods, the heavy-water reflector tank with shutdown rods and representative beam tubes, and the outer light-water poor. Eighty homogenized fuel zones per fuel element are used to represent the radical and axial {sup 235}U fuel grading. This model is the most sophisticated, physically accurate reactor physics model of the ANS currently available. The purpose of this summary is to demonstrate the MCNP methods and applications for the ANS.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

A series of experiments is to be made during the acceptance test program of the Fast Flux Test Facility (FFTF) to measure the gamma ray characteristics of the Fast Test Reactor (FTR) and to establish the performance characteristics of the reactor shield. These measurements are a part of the FFTF Reactor Characterization Program (RCP). Detailed plans have been developed for these experiments. During the initial phase of the Characteristics Program, which will be carried out in the In-Reactor Thimble (IRT), both active and passive measurement methods will be employed to obtain as much information concerning the gamma ray environment as is practical. More limited active gamma ray measurements also will be made in the Vibration Open Test Assembly (VOTA).

International Nuclear Information System (INIS)

An easy and simple method for gamma assay of large multi-gamma lines samples was introduced in this work. This method performs the assay using point source calibration. The correction factors for volume and self-attenuation are experimentally deduced from the spectra of different thicknesses samples utilizing the following two simple well known facts: large and small samples of the same homogenous material have identical specific activities; the self-attenuation of gamma line decreases as its energy increases. The method was successfully applied to naturally occurring radioactive material (NORM) large samples. This method does not require complicated mathematical procedures. Neither sample matrix data nor detector unit composition is needed.

International Nuclear Information System (INIS)

In clinical applications, it is very important to accurately determine the range of a proton beam in a patient. Recently, a prototype prompt-gamma scanning system, called a prompt-gamma scanner (PGS), has been constructed at Hanyang University in Korea with the collaboration of the Korean national cancer center (NCC), based on a series of Monte Carlo simulations. The PGS system is composed of a prompt-gamma collimator, a CsI(Tl) scintillation detector, a multi-channel analyzer (MCA), a precision movement system, and an integrated readout system. The prompt-gamma collimator is designed to effectively shield high-energy neutrons from the proton beam passage and subsequent capture gammas. The PGS system can be used to scan the distribution of the prompt gammas in the patient from the proton beam passage. The distribution of the prompt ...

International Nuclear Information System (INIS)

A LIXI (Light Intensifier X-ray Image) device has been employed in a real-time neutron radiography system. The LIXI is coupled to a video camera and the real-time images can be observed in a TV monitor, and processed in a computer. In order to get the real-time system operational, the neutron radiography facility installed at the IEA-R1 m nuclear research reactor of the IPEN-CNEN/S P has been optimized. The most important improvements were the neutron/gamma ratio, the effective energy of the neutron beam, decrease of the scattered radiation at the irradiation position, and the additional shielding of the video camera. Several one-frame as well as computer processed images are presented. The overall Modulation Transfer Function for the real-time system was obtained from the resolution parameter p = 0:44 +- 0:04 mm; the system sensitivity, evaluated for a Perspex step wedge, was determined and the average ...

International Nuclear Information System (INIS)

Excited states in the T_z=(1/2) nucleus "8"5Mo have been observed for the first time with the reaction "5"8Ni("3"2S,#alpha#n#gamma#) at 105 MeV. #gamma#-ray transitions in this nucleus have been assigned unambiguously by combining the information from the GASP #gamma#-ray array, the ISIS silicon ball, and the n-Ring neutron detector. Two band structures have been observed in this nucleus; they continue the smooth evolution of the known bands from the lighter N=43 isotones and have been tentatively assigned spins and parity on this basis. After reaching a maximum of collectivity at "8"3Zr, the trend with increasing mass is reversed, showing a smaller collectivity at "8"5Mo. The rotational behavior of the observed bands is discussed on the basis of the projected shell model calculations.

Energy Technology Data Exchange (ETDEWEB)

The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of [sup 87]Mo are studied in detail and explained by the evolution of the [gamma]-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N [>=] 47 for the spherical shape of the Mo isotopes. (orig.)

International Nuclear Information System (INIS)

An explicite PN solution of the multi-dimensional homogeneous neutron transport equation is given by expanding the angular flux into a series of geometry-independent spherical harmonics operators. An algorithm is developed for representing the spherical harmonic operators in orthogonal curvilinear coordinates. The general formulae are applied to two-dimensional spherical geometry; detailed P3 formulae are given. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The HEU and LEU fuel elements used in the ORR whole-core demonstration were gamma-scanned to determine the axial distribution of the {sup 140}La and {sup 137}Cs activities. Analysis of this data is now complete. From the {sup 140}La activity distributions cycle-averaged powers were determined while the {sup 137}Cs data provided a measure of the final {sup 235}U burnup in the fuel elements. A method for calculating correction factors for activity gradients transverse to the fuel element axis is presented and is applied to the first mixed core used in the demonstration during the gradual transition to an all LEU core. Results based on the gamma-scanning of the LEU fuel followers are also presented. Improved burnup calculations against which the experimental results are to be compared are now in progress. 7 refs., 21 figs., 3 tabs.

UK PubMed Central (United Kingdom)

Fasting plasma concentrations of magnesium were measured by neutron activation analysis in 30 non-diabetics and 87 diabetics (55 non-insulin-treated, 32 insulin treated). Plasma concentrations of magnesium...Full Text Available

International Nuclear Information System (INIS)

The aim of the present is to consider the influence of pr equilibrium processes on the activation cross-sections of "2"7 Al(n,p) "2"7 Mg, "5"1 V(n,p) "5"1"m Ti, "8"8 Sr(n,p) "8"8"m Rb, "9"4 Zr(n,p) "9"4"m Y and "9"7"Mo(n,p) "9"7"m Nb in the neutron energy range 13 to 15 MeV. Comparison with recent measurements is given for all considered isotopes. 2 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

TiH{sub 2} and TiD{sub 2} thick targets were bombarded with 100 to 200 keV protons or deuterons. Evidence for nuclear reactions was obtained by means of a surface barrier particle detector. Deuteron irradiation of TiD{sub 2} produced these observations: copious {approx}2.5 MeV neutrons and {approx}3 MeV protons from direct D-D reactions; gamma rays from p,{gamma} and n,{gamma} reactions; {approx}14 MeV protons from the secondary d({sup 3}He, p){alpha} reaction; and a signal between {approx}6-12 MeV that Kasagi et al. has tentatively identified as protons from the fusion of three deuterium nuclei. However, this signal has in it a strong interference signal from either neutrons or gamma rays that directly deposit energy in the detector. This interference spectra was measured by placing a thick absorber in front of the detector that stops up to 20 MeV protons, but ...

International Nuclear Information System (INIS)

The primary E1, M1 and E2 #gamma#-radiation in "8"7","8"8","8"9Sr observed after thermal neutron capture was compared with the predictions of single particle and giant resonance models. The nuclei feature a wide range of neutron binding energies between 6.3 and 11.1 MeV, which makes a 5.5 MeV spectrum of primary transition energies available for investigation. The (n, #gamma#) reaction was used to estimate the parameters of the spin-flip M1 giant resonance in strontium. The total energy weighted M1 strength of this resonance exceeds the results of shell model and random phase approximation calculations for "9"0Zr by a factor of 3-4. The E1 strengths were found to agree with the established giant dipole resonance model. The few data on primary E2 transitions do not allow to differentiate between the giant quadrupole resonance and the single particle models. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Dipole and quadrupole excitations in the semimagic N{sup .} = 50 nucleus {sup 88}Sr were investigated at the superconducting electron linear accelerator ELBE with bremsstrahlung produced at electron energies of 9.0, 13.2, and 16.0 MeV. About 160 {gamma} transitions were identified up to 12 MeV. By using polarized photons linear polarizations of about 50 {gamma} transitions were measured. In the energy range of 6 - 12 MeV there is only one M1 transition while all other transitions have E1 character. Statistical methods were applied in order to filter out inelastic transitions and to correct the intensities of the ground-state transitions for their branching ratios. The photoabsorption cross section obtained in this way provides information about the extension of the Giant Dipole Resonance towards energies below the neutron-separation energy. The experimental results are compared with existing data beyond the ...

Energy Technology Data Exchange (ETDEWEB)

Inactivation of aflatoxin B1 was studied by using gamma radiation and hydrogen peroxide. A 100-krad dose of gamma radiation was sufficient to inactivate 50 micrograms of aflatoxin B1 in the presence of 5% hydrogen peroxide, and 400 krad was required for total degradation of 100 micrograms of aflatoxin in the same system. Degradation of aflatoxin B1 was confirmed by high-pressure liquid chromatographic and thin-layer chromatographic analysis. Ames microsomal mutagenicity test showed loss of aflatoxin activity. This method of detoxification also reduces the toxin levels effectively in artificially contaminated groundnuts.

International Nuclear Information System (INIS)

The IGC-30 HPGe detector with MCA 'CANBERRA-10 PLUS' allows to determine surface contamination of areas of any type with a minimum error in radius 8-10 m, at a 'uniform' contamination. A modification of the CANBERRA hardware and software is described allowing determination of both the activity of a possible 'radioactive spot' and the activity of the whole observed surface. (author).

International Nuclear Information System (INIS)

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at "8"8Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in "8"7Sr and "8"9Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic?) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,#gamma#) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to "8"8Sr(d,t)"8"7Sr ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes activation measurements of the neutrons from fusion plasmas. We are primarily interested in two narrow bands of neutron energies around 2.5 and 14 MeV. The d-d reaction has two branches with nearly equal probability, one generating a 0.8 MeV {sup 3}He nucleus and a 2.45 MeV neutron, the other a 1 MeV triton and a 3 MeV proton. The d-t fusion generates a 3.5 MeV alpha particle and a 14 MeV neutron. The triton burnup can be defined as the ratio of triton removal rate to triton generation rate. The burnup depends on how well the tritons are confined in the plasma during their slowing down to energies that make d-t fusion probable. It is important to study the tritons as they have similar kinematics to the 3.5 MeV alpha particles in a d-t plasma. Threshold reactions make a distinction between 2.5 and 14 MeV neutrons possible. For calculating the ...

International Nuclear Information System (INIS)

The report describes the studies carried out to design a non-destructive system for the radiological characterization of packages containing LLW and MLW. This technique is applied for quantitative and qualitative gamma emitters determination in packages with homogeneous and heterogeneous matrices as well as the development of a maximum activity points location system. Development involves also the automatization for its industrial use.

Energy Technology Data Exchange (ETDEWEB)

The functional interaction between the peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) and its coactivator PGC-1{alpha} is crucial for the normal physiology of PPAR{gamma} and its pharmacological response to antidiabetic treatment with rosiglitazone. Here we report the crystal structure of the PPAR{gamma} ligand-binding domain bound to rosiglitazone and to a large PGC-1{alpha} fragment that contains two LXXLL-related motifs. The structure reveals critical contacts mediated through the first LXXLL motif of PGC-1{alpha} and the PPAR{gamma} coactivator binding site. Through a combination of biochemical and structural studies, we demonstrate that the first LXXLL motif is the most potent among all nuclear receptor coactivator motifs tested, and only this motif of the two LXXLL-related motifs in PGC-1{alpha} is capable of binding to ...

International Nuclear Information System (INIS)

Tritium is produced in large quantities at heavy water nuclear power reactors via the neutron activation reaction "2H(n,#gamma#)"3H. At Wolsung nuclear power plant which has a CANDU reactor, the tritium concentrations in coolant and in moderator systems are 1.5 Ci/Kg-D_2O and 35 Ci/kg-D_2O, respectively, after 12 years of operation. The airborne tritium concentration in main access area is normally less than 5 MPCa except short-term peaks. The average tritium concentrations in main access controlled areas are normally less than 100 MPCa. Tritium is mainly present in the air of workplace of CANDU reactors as a tritiated water vapour. Airborne tritiated water vapour enters the workers body via inhalation and absorption through skin and can result in a significant dose. The occupational doses from tritium at Wolsung NPP have been maintained below 1 man-Sv per year so far. The tritium contribution to the total plant man-Sv ...

UK PubMed Central (United Kingdom)

Zinc modulates the activity of glutamic acid decarboxylase, the rate limiting enzyme in the synthesis of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter. Low cerebrospinal...Full Text Available

International Nuclear Information System (INIS)

Results reported are for single dose exposures and refer to "6"0Co-#gamma#-irradiation. The RBE determined by V79 cell survival and based on the Do ratio was found to be 1.70#+-#0.4 ranging from 1.5 to 1.8. In the case of the regeneration of mouse jejunal crypts the RBE was calculated at ten cell curvival and was found to be 1.68. The maximum acute mouse skin reaction at a skin score of 2.0 was found to be 2.1 while the average skin reaction was 1.7. Growth retardation of Vicia faba bean roots measured at the level of 50% indicated an average RBE of 3.0 and a range of 2.7 to 3.7. The OER obtained for V79 cell survival was found to be 1.7 to 1.8. Comparison is made with the RBE and OER measurements for the neutron facilities at Clatterbridge, Fermilab and Louvain-la-Neuve which produce neutrons by the same nuclear reaction and whose physical specifications closely resemeble those of the Faure neutrons. ...

International Nuclear Information System (INIS)

Polymer sealing parts are widely used in various branches of engineering as detachable joints that operate at normal and cryogenic temperatures. They are also used in nuclear-power engineering to seal pumps, pipelines, etc., where they operate at 600-650 K under a neutron fluence of around 10"1"6 cm"-"2 (E #>=# 0.18 MeV) and concomitant #gamma#-irradiation of about 10"6 R. The fluoroplastic-based materials currently used degrade when irradiated in water at 320-360 K with a neutron fluence of 10"1"5 cm"-"2 (thermal neutrons) or 10"1"4 cm"-"2 (fast neutrons), and a concomitant #gamma#-irradiation dose of 2 x 10"6 R. The strength of these fluoroplastics decreases markedly after #gamma#-irradiation (from a cobalt source) at room temperature at doses above 10"6 R. For this reason, flexible and swelling graphites are finding ever increasing ...

Energy Technology Data Exchange (ETDEWEB)

The effective fraction of delayed photoneutrons ({beta}{sup ph}) has been theoretically defined and experimentally determined in various different configurations of the LWR-PROTEUS critical facility. The peculiarity lies in the fact that the reactor has D{sub 2}O in only one of the four fuelled zones, thus D({gamma},n)H reactions take place mainly in this region. The work is divided into three parts. The first part is devoted to the description of the LWR-PROTEUS facility and to the measurements of {beta}{sup ph}. These experimental values are derived from standard inverse-kinetics analysis of neutron flux decay experiments for each of seven different configurations, with nine additional groups of neutron precursors to account for photoneutron effects. In the second part, the coupled neutron and gamma Boltzmann equations are reduced to exact point kinetics equations using the photon ...

Energy Technology Data Exchange (ETDEWEB)

The security of ports and transportation is of utmost importance for the development of economy and the security of a nation. Among the necessary actions to ensure the security of ports and borders, the inspection of containers is one of the most time consuming and expensive procedures. Potential threats are the illegal traffic of radioactive materials that could be employed for the construction of weapons, as uranium and plutonium. New techniques for the inspections of containers should be fast, allow the detection and identification of dangerous materials, and be non-invasive, to reduce costs and delays. We propose to build a large surface photon and neutron detector based on plastic scintillator to identify the presence of fissile or fertile material inside a container. The detector consists of scintillator bars, wrapped in thin foils of reflecting material containing gadolinium for neutron capture and arranged in planes separated by ...

Energy Technology Data Exchange (ETDEWEB)

The detection efficiency of gamma scanning system in irradiated materials examination facility has been measured. Gamma-ray sources used in this experiment are Cs-Co standard sources a PWR spent fuel rod in which {sup 134}Cs and {sup 154}Eu peaks are clearly identified in the energy region of 500 to 1,600 keV. The distance between source and detector is about 1.6 m. A slit type collimator with 3 mm-width window and 30 mm-thick lead block are installed between source and detector. The detector is a HPGe detector. This equipment is mainly used in gamma scanning of irradiated nuclear fuel. The measured detection efficiency seems to be 1.89 x 10{sup -6} % for 1 MeV gamma-ray. With these results the activities of unknown sources could be measured. This results are expected to be used in the measurement of the absolute distribution of gamma emitting nuclides in ...

Energy Technology Data Exchange (ETDEWEB)

Diffuse {gamma}-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse {gamma}-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse {gamma}-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30{sup o} and 110{sup o} and between 136{sup o} and 216{sup o} and for Galactic latitudes between -10{sup o} and 10{sup o} are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region (l {element_of} [65{sup o}, ...

Energy Technology Data Exchange (ETDEWEB)

Tetracycline in solution of benzyl alcohol was used as an extracting agent to separate uranium from interfering elements in the determination of uranium and of isotopic ratio sup(235)U/sup(238)U by neutron activation analysis. Separation gives a recovery of 97% for uranium and the interferences from matrices of pitchblende and monazite are eliminated.

International Nuclear Information System (INIS)

New standardization techniques of samples in multielement instrumental neutron-activation analysis (INAA) of biological materials (BM) are considered. New methodical developments of sample preparation techniques, BM tableting, creation of comparison standards and standardization of packing material are suggested. Correlated data on concentration of different elements in standard specimens-comparison standards are presented for mass INAA, that is: for phenol-formaldehyde resin-base and human blood-base synthetic standards. 7 refs.; 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

The Helium and Lead Observatory (HALO) is a supernova neutrino detector under development for construction at SNOLAB. It is intended to fulfill a niche as a long term, low cost, high livetime, and low maintenance, dedicated supernova detector. It will be constructed from 80 tonnes of lead, from the decommissioning of the Deep River Cosmic Ray Station, and instrumented with approximately 384 meters of {sup 3}He neutron detectors from the final phase of the SNO experiment. Charged- and Neutral-Current neutrino interactions in lead expel neutrons from the lead nuclei making a burst of detected neutrons the signature for the detection of a supernova. Existing neutrino detectors are mostly of the water Cerenkov and liquid scintillator types, which are primarily sensitive to electron anti-neutrinos via charged-current interactions on the hydrogen nuclei in these materials. By contrast, the large neutron ...

International Nuclear Information System (INIS)

The production of three vector bosons in #gamma# #gamma# collisions studying the reactions #gamma# + #gamma# #-># W"+ + W"- + Z"0 and #gamma# + #gamma# #-># W"+ + W"- + #gamma#. 12 refs., 4 figs., 2 tabs.

Science.gov (United States)

The neutron-rich Mn isotopes from A=59 to 63 have been studied through multi-nucleon transfer reactions by bombarding a {sup 238}U target with a beam of {sup 70}Zn at an energy of E{sub lab}=460 MeV. Prompt {gamma} rays measured by the CLARA array have been identified unambiguously for each nucleus, using coincidence relationships with ions detected in the high-acceptance magnetic spectrometer PRISMA. The new data extends the knowledge of the low-lying level structure of Mn isotopes, which is discussed in terms of the systematics of the region. Results are compared with large-scale shell-model calculations using different effective interactions and valence spaces.

International Nuclear Information System (INIS)

An imaging position sensitive detector for charged particles, neutrons, X-and gamma rays has been developed. The novel feature of this scintillation imaging radiation detector is its ability to detect individual nuclear particle scintillations with a h igh degree of spatial resolution. The key elements of this detector system are a high gain, low noise image intensifier tube, a CCD camera and commercially available image processing hardware and software. This detector system is highly effective for applications such as low fluence and real time neutron radiography, mapping of radioactive contamination in nuclear reactor fuel rods, X-ray diffraction imaging, high speed autoradiography and in general position sensitive detection of nuclear radiation. Results of some of the exploratory experiments carried out using this detector system are presented in this paper. (orig.).

International Nuclear Information System (INIS)

The use of chemically selective laser ionization combined with beta-delayed neutron counting at ISOLDE has permitted identification and half-life measurements for "6"1Mn up through "6"9Mn. The 14(4)-ms half life for "6"9Mn is one of the shortest determined for any nuclide beyond the sd shell. Gamma-ray singles and coincidence spectra have been determined for the decays of "6"4","6"6Mn to levels of "6"4","6"6Fe, revealing strong deformation and vanishing of the N=40 subshell in the Fe isotopes.

International Nuclear Information System (INIS)

The use of chemically selective laser ionization combined with #beta# -delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms "6"1Mn up through 14-ms "6"9Mn . The measured half-lives are found to be significantly longer near N=40 than the values calculated with a quasiparticle random-phase-approximation shell model. Gamma-ray singles and coincidence spectroscopy has been performed for "6"4","6"6Mn decays to levels of "6"4","6"6Fe , revealing a significant drop in the energy of the first 2"+ state in these nuclides that suggests an unanticipated increase in collectivity near N=40 . copyright 1999 The American Physical Society.

Energy Technology Data Exchange (ETDEWEB)

It is planned to bulk-heat a unit cell of a fusion reactor solid-breeder blanket in a fission reactor to study thermo-mechanical and thermal-hydraulic properties of fusion blankets. This study investigates the neutronic feasibility of using the Power Burst Facility (PBF) for this purpose. Heating rates were calculated for a Li/sub 2/O experiment placed in the PBF test space. The ANISN code and a 56-group coupled neutron-gamma library based on FLUNG and VITAMIN C were used to compute the heating rates. The results show that an average heating rate level of 1-3 W/cc can be produced in PBF with a local power profile that should be typical of a fusion blanket unit cell.

International Nuclear Information System (INIS)

The final product of the radwaste conditioning process must satisfy certain requirments and physico-chemical properties in order to assure its safe long-term behaviour. Of course, the foreseen quality assurance and quality control should be conducted by means of non-destructive techniques. This work presents an over-view of various applicable non-destructive methods of analysis, showing their fields of investigation in testing waste packages, together with some arising practical problems. The most promising methods, such as eddy current testing, ultrasonic testing, #gamma#-scanning, #gamma#-spectroscopy, neutron counting and computerized tomography, are treated more deeply and some applications are presented. Particular attention is devoted to the development of a device based on computerized tomography; its essential components are reported and some design problems are also discussed.

International Nuclear Information System (INIS)

The thermal-neutron capture cross section (#sigma#_0_,_g) and the resonance integral (I_0_,_g) leading to the ground state of "2"4"2Am were measured by an activation method for neutron capture by "2"4"1Am. A method with gadolinium, which was similar to the cadmium difference method, was used to measure the cross section #sigma#_0_,_g with attention to resonances of "2"4"1Am. Americium chloride samples containing "2"4"1Am radioisotope were irradiated for 68 h in the long-irradiation plug of the Kyoto University Research Reactor, KUR. Wires of Co/Al and Au/Al alloys were used as monitors to determine thermal-neutron fluxes and epithermal Westcott's indexes at the irradiation positions. An #alpha#-ray spectrometer was used to measure the activity ratios of "2"4"2Cm to "2"4"1Am. On the basis of Westcott's convention, the #sigma#_0_,_g and I_0_,_g values were determined as 628#+-#22 b ...

Energy Technology Data Exchange (ETDEWEB)

Two methods for measuring indoor radon concentrations using activated charcoal have been tested. The first method is the well-known technique with direct gamma-measurements on the exposed canister after the sampling period. The other method uses a thermoluminescence dosemeter placed in the charcoal canister, giving an integrated value of the radon concentration.

Energy Technology Data Exchange (ETDEWEB)

From their genesis by weathering and sedimentation, bauxites, the principal aluminium ores, contain appreciable amounts of uranium and thorium. High resolution gamma spectrometry with a high purity germanium detector was used for an analysis of four industrially used bauxites from Gondama, Sierra Leone; Boke, Guinea; Weipa, Queensland, Australia; Gove, Northern Territory, Australia. Significant differences in uranium to thorium ratios and in activities of the uranium and thorium daughters were observed for the four bauxites. It was found that the bauxite from Gondama, Sierra Leone has an activity of only 10% compared with the others. Red mud tailings from such a bauxite may well be used as an additive to bricks, which is now illegal for normal red mud from more active bauxites. (author).

Energy Technology Data Exchange (ETDEWEB)

This paper is concerned with the validation of the 3D deterministic neutral-particle transport theory code EVENT for shielding applications. The code is based on the finite element-spherical harmonics (FE-P{sub N}) method which has been extensively developed over the last decade. A general multi-group, anisotropic scattering formalism enables the code to address realistic steady state and time dependent, multi-dimensional coupled neutron/gamma radiation transport problems involving high scattering and deep penetration alike. The powerful geometrical flexibility and competitive computational effort makes the code an attractive tool for shielding applications. In recognition of this, EVENT is currently in the process of being adopted by the UK nuclear industry. The theory behind EVENT is described and its numerical implementation is outlined. Numerical results obtained by the code are compared with predictions of the Monte Carlo code MCBEND and also with the results ...

International Nuclear Information System (INIS)

I have analyzed reduced neutron widths (#GAMMA#_n"0) for the subset of 1245 resonances in the nuclear data ensemble (NDE) for which they have been reported. Random matrix theory (RMT) predicts for the Gaussian orthogonal ensemble (GOE) that these widths should follow a #chi#"2 distribution having one degree of freedom (#nu# = 1) - the Porter Thomas (PT) distribution. Using the maximum-likelihood (ML) technique, I have determined that the #GAMMA#_n"0 values in the NDE are best described by a #chi#"2 distribution having #nu# =0.801 #+-# 0.052, which is 3.8 standard deviations smaller than predicted by RMT. I show that this striking disagreement is most likely due to the inclusion of significant p-wave contamination to the supposedly pure s-wave NDE. Furthermore, when an energy-dependent threshold is used to remove the p-wave contamination, ML analysis yields #nu# = 1.217 #+-# 0.092 for the remaining data, still in poor ...

Energy Technology Data Exchange (ETDEWEB)

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

Energy Technology Data Exchange (ETDEWEB)

The general usefulness of neutron activation analysis (NAA) for samples containing the platinum group elements (PGE) and Au, either as major or trace constituents, is discussed. Charged particle activation is shown to be a viable or complementary alternative. Proton (6-10 MeV) and alpha particle (9-15 MeV) beams, produced in a tandem Van de Graaff accelerator, have been established to be the most effective choice. By taking advantage of the Coulomb barrier effect and the fact that many charged particle induced reactions have relatively large threshold values, the same instrumental technique can be applied, with minor modifications, to a wide range of materials.

International Nuclear Information System (INIS)

A computational procedure is proposed to perform uncertainty analysis for the calculation of the isotopic inventory and radiological quantities obtained as a linear function of it, due to uncertainties in the activation cross sections. The method is applied to determine the uncertainty of the calculated shallow burial index (SBI) from activated type 304 stainless steel (SS) in the most neutron-exposed zone of the HYLIFE-II vessel structure. Results are obtained by means of an element-by-element study. Some other types of steel are also investigated for comparison purposes. The SS304 is confirmed to be the most promising steel option. 16 refs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

In order to evaluate the effects of radioactivity on active vegetal substances, samples of Fennel (Foeniculum vulgare Miller., fructus), Guarana (Paulinia cupana, Kunth, semen), Gingko (gingko biloba, L., folium), and Kawa-Kawa (Piper methysticum G. Forst, rhizoma), were treated with scaling doses (0 to 25 KGy) of gamma radiation (Co{sup 60}). The 'blind test' methodology was used. The active substances from each sample were analysed by qualitative and quantitative methods after radiation. There were no significant differences seen between the control sample (0 KGy) and the irradiated samples. Microbe contamination was significantly reduced, about 10000 CFU/g, with the initial 5 KGy dose. It was concluded that gamma radiation can be used as an alternative procedure to reduce microbiologic contamination in medicinal plants. Before this procedure can be extended to other medicinal ...

International Nuclear Information System (INIS)

In this experiment, we measured the detection efficiency of gamma-scanning system of Irradiated Materials Examination Facility (IMEF) in Korea Atomic Energy Research Institute(KAERI) for the spent PWR fuel and activity known sources with high activity. We measured the absolute detection efficiency of gamma scanning system of IMEF to the "1"3"7Cs-source with 10.4 GBq and "6"0Co source with 25.9 GBq High-activity sources as standard sources, and a fuel burned in the KORI -1 reactor of the Kori Nuclear power plant. In analyzing, we used three peeks those were the 661.64 keV peak form "1"3"7 Cs 1173.23 and 1332.51 keV"6"0 Co sources, and 14 peaks of "1"3"4Cs and "1"5"4Eu on the spent fuel gamma spectrum which are in the energy range from 500 to 1,600 keV. We find second order equations for detection efficiency by using our experimental results. The equation show ...

Energy Technology Data Exchange (ETDEWEB)

Solving a coupled set of differential equations formed by a Fokker-Planck equation and a set of master equations, we can calculate the number of 'prefission' particles (n,p,a), which are emitted from a hot, rotating compound nucleus. Furthermore we get their energy spectrum and their angular momentum distribution. Our results depend sensitively on the friction parameter {gamma}, the inertia M and the fission potential. Comparing the results with experimental data, we may learn something about these quantities. The investigations have been made for {sup 187}Ir and {sup 185}Os. (orig.).