Accession Number : AD0612994

Title :   THERMAL NEUTRON SPECT+A NEAR ABSORBERS.

Descriptive Note : Revised ed.,

Corporate Author : ATOMIC ENERGY OF CANADA LTD CHALK RIVER (ONTARIO)

Personal Author(s) : Bigham,C. B.

Report Date : 04 AUG 1964

Pagination or Media Count : 8

Abstract : The perturbation in a thermal neutron spectrum near an absorber immersed in a moderator has been studied using activation techniques. The results show two separate effects for pure thermal spectra, a 'transmission hardening' depending on the energy variation of the absorber cross section and a 'boundary effect' depending on the energy variation of the moderator scattering cross section. These results are in agreement with energy-dependent Milne problem calculations for a mass one, free-gas moderator and with another experimental result when a third 'source hardening' effect in reactor spectra is considered. (Author)

Descriptors :   (*THERMAL NEUTRONS, NEUTRON SPECTRUM), (*NEUTRON SPECTRUM, NEUTRON ABSORBERS), REACTOR MODERATORS, PERTURBATION THEORY, GRAPHITE, BORON, CADMIUM, ACRYLIC RESINS

Distribution Statement : APPROVED FOR PUBLIC RELEASE