Accession Number : AD0611265

Title :   THE EFFECT OF NEUTRONS WITH ENERGIES ABOVE 6 MEV ON FISSION FOIL DATA,

Corporate Author : ARMY NUCLEAR DEFENSE LAB EDGEWOOD ARSENAL MD

Personal Author(s) : Kappes,Jean ; McNeilly,John H.

Report Date : OCT 1964

Pagination or Media Count : 24

Abstract : The report describes a calculational correction to neutron-flux measurements that were made using fission foil detectors exposed to a radiation environment in which approximately 7.5 percent of all neutrons had an energy greater than 6 MeV. This investigation has shown that in many cases it will be necessary to correct the fission foil results because of the increased cross section at high neutron energies. In the particular example presented, where 7.5 percent of the total number of neutrons had energies greater than 6 MeV, the correction for U238 ranged between 21.9 and 27.3 percent and was marginal for Np237 (7.2 to 10.6 percent). Although corrections existed for the remaining foils, they were all within the quoted experimental error of =10 percent for the threshold detector system. The investigation describes an approach to the solution of the problem posed by high energy neutrons on threshold detector results, and emphasizes the fact that the problem must be considered in all future applications of this measurement technique. (Author)

Descriptors :   (*NEUTRON DETECTORS, FOILS(MATERIALS)), (*NEUTRON FLUX, MEASUREMENT), FISSION PRODUCTS, NUCLEAR CROSS SECTIONS, URANIUM, NEPTUNIUM, CALIBRATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE