Accession Number : AD0125191

Title :   Attainment of Neutron Flux-Spectra from Foil Activiations

Descriptive Note : Master's thesis

Corporate Author : AIR FORCE INSTITUTE OF TECHNOLOGY WRIGHT-PATTERSON AFB OH

Personal Author(s) : Uthe, Jr , Paul M

PDF Url : AD0125191

Report Date : Mar 1957

Pagination or Media Count : 94

Abstract : Several analytical methods are described for obtaining neutron flux-spectra knowledge from foil data. The response functions used are the nuclear reaction characteristics of threshold, fast fission, and resonance type foils. Two previously used methods and two new methods are discussed. The previously used methods are the Trice Method and the Cadmium Difference Method. The Trice Method, applicable in the fast neutron energy region, uses a step function cross section representation. The step function energy threshold is determined by assuming a differential flux function. The Cadmium Difference Method, applicable in the 1/E energy region, uses the resonance activation integrals of resonance type foils as cross section parameters. Although consideration is given to these methods, major interest is focused on two new methods. These methods are called the Polygonal Method and the Polynomial Method. The Polygonal Method uses the cross sections in their true form and represents the flux-energy spectrum by a combination of linear functions of energy. In performing the necessary calculations, difficulty in selecting certain energy parameters is experienced. The Polynomial Method uses the cross sections in their true form and represents the flux-energy spectrum by a weighting function times a polynomial. The degree of the polynomial is one less than the number of different foils used. A digital computer is conveniently used for the required numerical calculations. The result of several test cases using the Polynomial Method indicates that considerable improvement over the Trice Method is achieved.

Descriptors :   *NEUTRON FLUX, *NEUTRON SPECTRUM, *NUCLEAR RADIATION SPECTROSCOPY, DETERMINATION, FOILS(MATERIALS), MATHEMATICAL ANALYSIS, THESES

Subject Categories : Fission Reactor Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE