[en] The neutron response function for a stilbene detector over the energy region of 0.5 to 20 MeV was calculated by the stochastic Monte Carlo method. The results of calculation were tested by comparison with the experimental shapes of the single energy lines of 1.2, 2.5, 5, 14.8, and 19 MeV neutrons, and for three stilbene detector specimens 10x10, 20x20, and 45x45 mm in size. Interesting findings were obtained regarding the effect of the neutron incidence angle. The code has been set up so as to enable the effects of the individual factors contributing to the response function to be examined and compared with observed data

[en] Liquid scintillation counting makes it possible to measure radionuclides that cannot be quantified by conventional spectrometry because of lack of or a low gain of gamma and alpha emissions. With respect to the environmental issue, ³H, ⁹⁰Sr, ⁸⁹Sr, and ⁶³Ni are of particular interest. A procedure is proposed for a general determination of the measuring and correction windows. This procedure allows a window to be chosen ensuring a relatively high robustness of measurement of mixed radionuclide solutions. A procedure to establish corrections for the contribution of other emissions in the sample is also described. For the measurement of actual samples, a procedure is proposed where the measuring window is changed in dependence on sample quenching, and the usual causes of quenching are discussed. The problem of measurement of quenched background spectra is also treated

[en] A single-channel transimpedance preamplifier for fast dielectric detectors is described. The main specifications of the preamplifier are: rise time is 1,5 ns; gain is 3,5 mV/μ A (with two section- 210 mV/μ A); r.m.s input noise is 30 n A; power consumption is 22 m W. Depending on supply voltage, the parameters may vary in a wide range. 5 refs

[en] This study was conducted to compare the results of gamma spectrometric analysis using the Scaling Confirmatory Factor Analysis (SCFA) method to that of Genie2K, which uses a more traditional method. Gamma ray spectra had had been acquired for several gamma standard sources, all of which except Co-57 and Eu-152 being single gamma ray emitting nuclides. These standard sources spanned the energy range from 60 keV (Am-241) to 1116 keV (Zn-65). The standard sources were counted at 3 different geometries at 3 different geometries, with source-detector distances of 0, 5, and 15 cm. Using single gamma ray spectra collected at a given counting geometry, and the certificate file, an efficiency calibration was created for that geometry. Three different test spectra, one for each counting geometry, had been created by combining several of the standard source spectra. The efficiency calibrations created for the 3 geometries were loaded into the respective spectrum files. Each test spectrum was analyzed using the standard Genie2K engines; Peak locate, Peak search, Interactive peak fit, Background subs-traction, Efficiency correction, and Nuclide Identification with interference analysis. The results of the various calculation steps were reported. In all 3 test cases, the SCFA method identified all the nuclides correctly. The K-40 activities calculated by the SCFA method were reasonably close to that from Genie2K analysis. In general, the quantitative results of the SCFA method were impressive in all 3 cases. On a positive note, the SCFA method did identify low yield gamma lines in Eu-152, which were not identified by the Genie2K analysis. This substantiates claim that the SCFA is more sensitive than the traditional method of spectrum analysis. (authors)

No abstract available

[en] Construction of the heat radiator capillary model is described. It is aimed for creation of an atomized system which permits the functioning of silicon strip-detectors during a long time (5000 hours) and intensive irradiation (approx 10 Mrad) without any access to it for repair works

[en] During 1994 the test measurements for HERA-B experiment. Monte Carlo simulation by GEANT was used to estimate the total efficiency for the modified trigger and hodoscope counters

[en] Focusing mirrors in 1 or 2 dimensions can be used to increase the intensity in a small-angle instrument while maintaining high resolution. Using the recently added toroidal mirror region type in MCLlB (Monte Carlo library for neutron instrument design), we compare five mirror shares: the ideal ellipsoid the tangent toroid, 8 tangent toroidal segments, 8 tangential cylindrical segments, and 20 tangential cylindrical segments. A small-angle scattering instrument on a spallation source was simulated to study resolution. Comparisons show that the ellipsoid provides superior resolution, but that the 8 tangential toroids are a good compromise. A resolution of 0.00056 Angstrom ^-1(rms), or (-)(+)11% at Q = 0.005 Angstrom ^-1, was achieved in the simulation using neutrons in the wavelength range 4-15 A. The count rate is high because the full area of the moderator is viewed

[en] There is a need in the United States for a state-of-the-art, cold-neutron, crystal backscattering spectrometer (CBS) designed to investigate the structure and dynamics of condensed matter systems by the simultaneous utilization of long wavelength elastic diffraction and high-energy-resolution inelastic scattering. Cold neutron spectroscopy with CBS-type instruments has already made many important contributions to the study of atomic and molecular diffusion in biomaterials, polymers, semiconductors, liquid crystals, superionic conductors and the like. Such instruments have also been invaluable for ultra high resolution investigations of the low-lying quantum tunneling processes that provide direct insight into the dynamical response of solids at the lowest energies. Until relatively recently, however, all such instruments were located at steady-state reactors. This proposal describes HERMES I (High Energy Resolution Machines I) a CBS intended for installation at the LANSCE pulsed neutron facility of Los Alamos National Laboratory. As explained in detail in the main text, the authors propose to construct an updated, high-performance CBS which incorporates neutron techniques developed during the decade since IRIS was built, i.e., improved supermirror technology, a larger area crystal analyzer and high efficiency wire gas detectors. The instrument is designed in such a way as to be readily adaptable to future upgrades. HERMES I, they believe, will substantially expand the range and flexibility of neutron investigations in the United States and open new and potentially fruitful directions for condensed matter exploration. This document describes a implementation plan with a direct cost range between $4.5 to 5.6 M and scheduled duration of 39--45 months for identified alternatives

No abstract available