抄録
The disintegration rates and photon emission rates were calculated for products of simultaneous fission of 235U with thermal neutrons at the following periods after fission: 1, 3, 7, 14, 30, 50, 100, 200 days and 1, 1.5, 2, 3, 5, 10 years.
Information on tofal chain yields was largely referred to Katcoff (1958). Decay schemes were from Strominger, Hollander and Seaborg (1958). The distribution of independent yields was neglected. The photons were classified into nine energy groups, covering the energy range between 0.0 and 1.6 MeV, which correspond to the photopeaks in Nal (Tl) scintillation spectra. The total disintegration rates and the total photon emission rates also calculated as functions of time after fission.
All the results were tabulated and compared with other published calculations.
Total disintegration rate (total activity): The results induced from the report were slightly larger than calculations of Hunter and Ballou (1951) and of Björnerstedt (1959) over the entire range of decay times.
Percentage contribution of individual radionuclides to total activity: The present results were in good agreement with Björnerstedt's calculations (1957, 1959).
Total photon emission rate (total gamma activity) and group distribution of gamma activities (gamma spectrum): The results induced from the report were in good agreement with the Björnerstedt's calculations (1959) over the entire range of decay times except one day after fission and over the entire energy range except the lowest groups (0.030.05, 0.080.09 MeV) and fifth energy group (0.280.37 MeV).
