Accession Number : AD0621119

Title :   THE THERMAL NEUTRON SPECTRUM IN A FINITEMASS MEDIUM.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s) : Sims,Ernest Park

Report Date : AUG 1965

Pagination or Media Count : 132

Abstract : The distribution of neutrons at thermal energies in a monatomic Maxwellian gas is determined. Spectra are found in various mass media and for varying amounts of absorption by numerically solving Corngold's higher-order gas equation; a result that is new. From the spectra obtained the average neutron velocity is found and the thermal diffusion length squared is calculated. Using this method and a neutron age from a moments method calculation, the migration area in selected real nuclides is determined. The deviations from Maxwellian of the thermal neutron spectra are used to determine the energy at which a neutron becomes thermal. This effective thermal transition energy, E*, is found for media of various mass with varying amounts of absorption. The neutron thermal spectrum is found to be generally non-Maxwellian for values of the absorption parameter greater than 0.01.

Descriptors :   (*THERMAL NEUTRONS, NEUTRON SPECTRUM), (*NEUTRON SPECTRUM, THERMAL NEUTRONS), GASES, NEUTRON TRANSPORT THEORY, NEUTRON FLUX, NEUTRON AGE, ENERGY, GASES, COMPUTER PROGRAMMING

Distribution Statement : APPROVED FOR PUBLIC RELEASE