Cumulative yields in the photofission of 232Th and 238U in the symmetric region

Abstract

Fission mass yields for molybdenum-99, ruthenium-103 and -105, palladium-109 and -112, silver-111, cadmium-115, and tin-121 and -125 in the 25 MeV bremsstrahlung beam fission of thorium-232 and uranium-238 have been determined using radiochemical methods. The mass–yield curve for thorium-232 shows a pronounced third peak in the symmetric region, contrary to the results of Hiller and Martin with 69 MeV brehmsstrahlung. In the case of uranium-238, the curve is flat between mass numbers 111 to 121 in contrast to the 14 MeV neutron fission of the nuclide which shows a valley in this region.