Accession Number : AD0424445

Title :   HEAVY MASS YIELDS IN THE SLOW NEUTRON FISSION OF U233,

Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Personal Author(s) : Bunney,L. R. ; Scadden,E. M.

Report Date : 12 SEP 1963

Pagination or Media Count : 21

Abstract : The chain yields of masses 157, 159 and 161 in the thermal neutron fission of U233 were determined by radiochemical methods. The last radioactive member of the mass chain was isolated and its activity measured relative to Mo-99. With this ratio and pertinent data from the thermal neutron fission of U-235, the mass chain yield was calculated. The chain yields are: mass-157 (15.4 hr - Eu-157) -.00635%, mass-159 (18.5 hr - Gd-159)-.000905% and mass-161 (6.9 d - Tb-161)-.000117%. These yields are higher than was to be expected from analogy with the relative yields from thermal neutron fission of U-235 and U-238. A possible explanation is given. The chain yields of masses 91, 141, 143, 144, 147, 149, 151 and 153 in the thermal neutron fission of U-233 and U-235 were also determined. The values, when compared to the literature values for the chain yields, provided an estimate of the accuracy of the radiochemical measurement. It is estimated to be = 10%. A new value has been calculated for the chain yield of mass-157 in the thermal neutron fission of U-235. An improved value was obtained for the chain yield of mass-156 in the thermal neutron fission of U-233. (Author)

Descriptors :   (*URANIUM, RADIOACTIVE ISOTOPES), (*FISSION PRODUCTS, THERMAL NEUTRONS), (*RADIOACTIVE ISOTOPES, URANIUM), ALUMINUM, FOILS(MATERIALS), RADIOCHEMISTRY, RARE EARTH ELEMENTS, MOLYBDENUM, RADIOACTIVE DECAY, CHEMICAL ANALYSIS

Distribution Statement : APPROVED FOR PUBLIC RELEASE