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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.; Mullin, Frank Edward & Gannon, L. J.
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

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

Fast Neutron Imaging Systems

Description: 3-dimensional position-sensitive solid state detectors. In particular, extensive investigation had been carried out on 3-D CdZnTe detectors for detection of fission neutrons.
Date: October 11, 2006
Creator: He, Zhong
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

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

Handheld Device for Simultaneous Monitoring of Fast Neutrons and Gamma Rays

Description: Currently at the INEEL, a handheld device is being developed to measure fast neutrons and gamma rays using a single detector instead of a previous two detector system. The handheld detection system presented here uses a single 1/2 inch (diameter) by 1/2 inch (long) liquid scintillator detector (BC501). This means the detection system can be made smaller, lighter, less expensive, and is expected to be more sensitive than the original system. A smaller and lighter device makes it possible to be used in several applications such as customs inspection, border security, environmental radiation monitoring, and so on. The use of only one detector requires that the neutrons and gamma rays be distinguished by the shape of their pulses in the detector. Two methods of pulse shape discrimination (PSD) are: presented here, charge integration and crossover timing. Figures of merit were calculated for both methods for a threshold energy range of 50 to 600 keV. Results show that the crossover method gives much better PSD for electron energy of 100 keV and lower, whereas the charge integration method leads to better separation above 100 keV. However, the neutrons and gamma rays are totally separated for energies of 100 keV and above in both techniques. We are currently designing a miniaturized electronic system to be incorporated in the handheld device.
Date: November 1, 2001
Creator: Aryaeinejad, Rahmat; Reber, Edward Lawrence & Spencer, David Frazer
Partner: UNT Libraries Government Documents Department


Description: The program was written for the Philco-2000 computer to provide a nuclear design computing tool equivalent to the IBM-704 computer program MUFT-4 and to provide a set of routines for a future spatial multigroup program, P/sub 3/ MG-1. In addition to the features of its 704 predecessor, MUFT-5 provides a more complete isotopic edit, an optional blackness coefficient edit, and the use of a complete P/sub i/->i>s library. The resultant program is found to be easier to use because of the simplicity of running several problems, more valuable because of the many additional results that are edited, and more economical because of the changes made in programming. (auth)
Date: February 1, 1961
Creator: Bohl, H. Jr. & Hemphill, A.P.
Partner: UNT Libraries Government Documents Department


Description: To one whose responsibility it is to make evaluations of the degree of hazard existing in the radiation field of a nuclear accelerator or a nuclear reactor, the valid estimate of the contribution of neutrons to such a field is of considerable importance. The degree of difficulty of such a measurement depends strongly upon the information desired - whether (1) simply the presence of 'slow' and 'fast' neutrons in significant numbers is in question, or (2) a measure of flux densities within known energy intervals is required, or (3) a direct estimate of the specific rate of energy absorption due to neutron-produced effects in a given medium is desired. The importance of securing trustworthy estimates of the neutron field can be appreciated by recalling that the biological damage due to a given amount of ionization produced in biological tissue by effects due to neutrons is estimated to be several times the damage due to a similar amount of ionization produced by X-rays or gamma rays. This 'relative biological effectiveness' must be evaluated by carefully controlled animal experiments. Its value appears to range from about 2.5 for slow neutrons to abount 10 for fast and high energy neutrons. Of course the value obtained may also be a function of the particular biological variable under observations, and from some experiments a value as high as 20 for fast neutrons may be indicated.
Date: January 11, 1952
Creator: Moyer, B.J.
Partner: UNT Libraries Government Documents Department

2000 KILOWATT SODIUM TEST FACILITY. Project Description and Progress Reports, June 30, 1958 through September 30, 1959

Description: The design and construction work completed on the 2000-kw Sodium Teat Facility during the period from April 1958 to Oct. 1959 is described. The purpose of the facility project in to test models of equipment components which are to be used in a moltsn plutonium, sodiumcooled fast reactor. (D. L.C.)
Date: March 1, 1961
Creator: Whinery, L.A.
Partner: UNT Libraries Government Documents Department


Description: An analysis of the EGCR core structure was made to determine the lateral deflections (bowing) of the graphite columns resulting from shrinkage caused by fast-neutron irradiation, the life expectancy of each column due to restraints imposed on the bowing, and the reaction forces induced in the supporting structures. Based on currently avallable data for EGCR type graphite shrinkage and assuming experimental loop operation, a maximum bowing potential of 3.61 in. was calculated for an interior column. It was found that strains equivalent to the rupture strains observed from tensile tests could be expected after 4 to 6 years of full-power operation. Over half of the columns will reach these strains before the 20-yr reactor design life is reached. (auth)
Date: April 14, 1961
Creator: Moore, S.E. & Shaw, W.A.
Partner: UNT Libraries Government Documents Department