Abstract
The cumulative yields of fission products 89 90Kr, 136mI, 137,139Xe, 140Cs, 144La, and l48Ce in thermal neutron-induced fission of 2 3 5 U have been determined using rapid gamma ray spectroscopic method. To obtain the absolute yield of fission products having half-lives between 30 s and 230 s, 12 gamma multi-scaling spectra were collected in periods of 11-min duration after an 11 s irradiation and a 67 s cooling period. Gamma rays and photopeak areas of interest were assigned to the fission products by their energies and half-lives. Fission product activities wert evaluated from spectral data using growth and decay calculation, and fission yields were determined by the total number of fissions in the sample, which was measured directly using track-etch technique. Results of the cumulative fission yields, among which the non-gaseous fission products are reported for the first time, are compared with previous measurements and with recommended yields in recent evaluations. © R. Oldenbourg Verlag, München 1984