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Notes on Predicted Fast Neutron Dose from Thermal Neutron Data in Water

Description: Abstract: "An appropriate method has been applied to predict fast neutron dosimeter data from thermal neutron measurements. Results are compared with actual dosimeter data and it is concluded that the method presented gives a good approximation for fast neutron dose. This is important since in many previous experiments fast neutron dosimeter data had not been taken, but thermal neutron data had been obtained."
Date: 1953
Creator: Stone, Henry E.
Partner: UNT Libraries Government Documents Department

Fast Neutron Interactions with Li⁶ and Li⁷

Description: Abstract: "Measurements have been made of the cross sections for the reactions Id-6(n, dn)He-4 and Li-7(n, tn)He-4 over an incident neutron energy range of 5 - 14 MeV. The energy and angular distributions of all reaction products were determined."
Date: July 18, 1963
Creator: Rosen, Louis
Partner: UNT Libraries Government Documents Department

The Time-Dependent Neutron Flux for a Pulsed Subcritical Assembly

Description: Report discussing a study regarding the time-dependent neutron flux for a pulsed subcritical assembly. From abstract: "A two-group analysis has been applied to the transient behavior of the thermal flux in a subcritical assembly which has been given a short burst of fast neutrons."
Date: April 15, 1957
Creator: Fults, Stanley C.
Partner: UNT Libraries Government Documents Department

Fast Neutron Sensitivity of the CP Meter

Description: Abstract: "The sensitivity to fast neutrons of a CP Meter ionization chamber of the type used for health physics beta and gamma survey measurements has been investigated."
Date: June 10, 1949
Creator: Baker, E. E.; Gydesen, F. R. & Whipple, G. H., Jr.
Partner: UNT Libraries Government Documents Department

Fast Neutron Effects on Du Pont 1290 Film

Description: Abstract: "Fast neutron effects on a widely used x-ray film have been investigated. The neutron flux was provided by the (d, t) reaction of a Cockcroft-Walton accelerator. Integrated exposures to 10-10 n/cm-2 were given the film. It was found that perturbations on film that were pre-exposed to Co-60 gamma rays from 10 to 2000 r were negligible. Simultaneous exposure of neutrons plus gammas also indicated negligible effect on the film insofar as the gamma dose was concerned."
Date: June 13, 1958
Creator: Block, Seymour & Hughes, Lewis
Partner: UNT Libraries Government Documents Department

Analysis of Lid Tank Neutron Data for Lead and Iron

Description: Abstract: An analysis of the lid tank neutron data for Pb-H2O and Fe-H2O is made. "Effective" fast neutron cross sections for the metals are obtained. This is based on the "one collision theory" of shielding. Values are 3.4 barns for Pb and 2.0 barns for Fe. These compare very well with those obtained by Albert and Welton based on other lid tank data and another method of calculation.
Date: January 5, 1951
Creator: Podgor, S.
Partner: UNT Libraries Government Documents Department

MUFT Revision : A Fast Neutron Spectrum Code for the IBM-650

Description: Report documenting the MUFT-R program, which is "designed to solve the fast neutron transport problem for general mixtures of elements and obtain sets of average fast neutron diffusion constants for specified portions of the fast energy spectrum" (p. iii). Includes detailed derivations of utilized equations.
Date: 1962
Creator: Grimesey, Robert A.; Mullen, Frank Edward & Gannon, L. J.
Partner: UNT Libraries Government Documents Department

Directional Stand-off Detection of Fast Neutrons and Gammas Using Angular Scattering Distributions

Description: We have investigated the response of a DoubleScatter Neutron Spectrometer (DSNS) for sources at long distances (gr than 200 meters). We find that an alternative method for analyzing double scatter data avoids some uncertainties introduced by amplitude measurements in plastic scintillators.Time of flight is used to discriminate between gamma and neutron events, and the kinematic distributions of scattering angles are assumed to apply. Non-relativistic neutrons are most likely to scatter at 45°, while gammas with energies greater than 2 MeV are most likely to be forward scattered. The distribution of scattering angles of fission neutrons arriving from a distant point source generates a 45° cone, which can be back-projected to give the source direction. At the same time, the distribution of Compton-scattered gammas has a maximum in the forward direction, and can be made narrower by selecting events that deposit minimal energy in the first scattering event. We have further determined that the shape of spontaneous fission neutron spectra at ranges gr than 110 m is still significantly different from thecosmic ray background.
Date: October 25, 2009
Creator: e., Vanier P.; Dioszegi, I.; Salwen, C. & Forman, L.
Partner: UNT Libraries Government Documents Department

Total Cross Sections of Tritium, Hydrogen, and Helium for Fast Neutrons

Description: Abstract: "By using gaseous samples in neutron transmission experiments the total cross section of tritium has been measured over the energy region from 0.3 to 7.0 Mev and at the following additional energies: 14.1, 18.0, 19.1, and 20.0 Mev. A plot of cross section versus neutron energy shows a broad maximum with the greatest value of 2.5 barns at 3.7 Mev. Cross sections for helium were measured in the energy region from 1 to 3 Mev and for both hydrogen and helium at 14.1 Mev."
Date: October 1952
Creator: Coon, J. H.; Bondelid, R. O. & Phillips, D. D.
Partner: UNT Libraries Government Documents Department

Chemical Engineering Division Fast-Neutron Dosimetry, Annual Report: July 1975-June 1976

Description: One of the objectives of the Dosimetry and Damage Analysis Center is to provide standardized dosimetry technology for materials-study programs within the ERDA Division of Magnetic Fusion Energy. Current efforts have included characterization of neutron environments in terms of fluence and spectral distribution for materials experiments conducted at the Lawrence Livermore Laboratory's (LLL) Rotating Target Neutron Source and at the LLL-Davis Cyclograaff. Environment characterization efforts at Brookhaven National Laboratory's High Flux Beam Reactor and those pertaining to an enriched-uranium converter for the ANL CP-5 reactor are also described. The capability of calculating material radiation damage parameters associated with these neutron environments is demonstrated. Average fission yields determined from two fast-neutron irradiations and one thermal-neutron irradiation are compiled for laboratories participating in the inter-laboratory Reaction Rate program. These results are in excellent agreement with literature values. Progress on the development of boron-10 and lithium-6-loaded liquid scintillation detectors for detecting very low intensity neutrons is presented. Material purification tests and performance tests of scintillation mixtures are described.
Date: 1976?
Creator: Heinrich, R. R.; Greenwood, L. R.; Kennerley, R. J.; Chellew, N. R.; Popek, R. J.; Malewicki, Russell et al.
Partner: UNT Libraries Government Documents Department

Scintillation Spectrometer System for Measuring Fast-Neutron Spectra in Beam Geometry

Description: A high-energy liquid-organic scintillation spectrometer system is described. This spectrometer was developed to measure neutron spectra in extracted beams from zero-power fast reactors. The highly efficient NE-213 scintillation solution was used as the neutron detection medium. Identification and removal of gamma-ray-induced events was accomplished using electronic pulse shape discrimination. Instrumentation used to process the discrete pulses stemming from neutron and gamma-ray interactions, within the scintillation solution, is described in detail. Evaluation of the system's performance is discussed for a gamma-ray discrimination ratio of nominally 1000:1, a total count-rate of 3000 cps, and a dynamic range corresponding to neutron energies from 1 to 10 MeV. Operation above 10 MeV is certainly possible. However, since the neutron flux above 10 MeV was negligible in the radiation fields of interest in this work, the operating characteristics of the spectrometer were not evaluated above 10 MeV. Neutron spectra are reported for extracted beam measurements made on ZPPR assembly 4, phase 2.
Date: May 1977
Creator: Simons, G. G.; Larson, J. M. & Reynolds, R. S.
Partner: UNT Libraries Government Documents Department

A Simple Calibration and Checking Facility for Fast and Slow Neutron Detectors

Description: From introduction: The principal work described below is the development and tests of a slow neutron flux generator based on a generator developed at the University of California (UCRL 8359, W. Patterson, Roger Wallace, "A Method of Calibrating Slow Neutron Detectors"). It is shown that a tolerance flux density of slow neutrons results within a cubical cavity 15 inches on an edge with 4-inch-thick walls of water or paraffin wax when a plutonium-beryllium source emitting about 7 million neutrons per second is placed within the cavity according to a standard procedure. The principle on which the generator is based is that the fast neutrons from the source are slowed to near thermal velocities by scattering from the cavity walls. (Although the principal interest is in the slow flux, a primary fast flux is present at any point depending on the inverse square of the distance from the source.) The variation of slow neutron flux density over the walls of the cavity is unimportant for the calibration of thermal neutron detectors which follow a 1/v or 1/E response law (where v and E are the neutron velocity and energy), so that the detector is sensitive mainly to the slow neutron flux. As stated, the method provides a slow neutron flux density (instead of the neutron density only) so that a calibration for detectors placed within the cavity can be given either in terms of flux density of slow neutrons or, by simple conversion, in terms of dose-rate.
Date: January 28, 1959
Creator: Redmond, A. H.
Partner: UNT Libraries Government Documents Department