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The γ-ray spectra arising from the decay of 41-day 148Pmm and 5-day 148Pmg produced by the irradiation of 2.6-year 147Pm in a thermal reactor neutron flux have been measured with a Ge(Li) detector. The absolute probabilities for γ-ray emission were determined from an analysis of the spectra and used to construct an improved decay scheme for the two isomers and to obtain their production cross sections. The 147Pm thermal neutron cross sections obtained after making a small correction for epithermal capture are 84 ± 10 b and 72.4 ± 3.0 b for the production of the 148Pmg and 148Pmm activities respectively, in good agreement with the results of Fenner and Large, but significantly smaller than other recent measurements.

Fission yields of 135I and 140Ba have been measured relative to the yields from 235U for samples of different fissile materials irradiated in the NRU reactor in a flux of 2.7 × 1014 neutrons/cm2 sec for 24 hours. The relative 135I contents of the samples were determined from the reactivity effect of the daughter 135Xe in the Chalk River Pool Test Reactor using a pile oscillator. The relative concentrations of 140Ba were determined by gamma-ray counting of the daughter 140La. The fractional yields, normalized to 0.0625 for both fission products in 235U fission, are:[Formula: see text]In the fission of 233U and 239Pu the cumulative yields to 135I and 140Ba are approximately 20% and 7% less than the mass-spectrometrically-measured cumulative yields to 135Cs and 140Ce respectively. The differences are attributed to direct formation of 135Xe and 140La.