Alpha-particle and gamma-ray emission probabilities in the decay of 242Pu

Abstract

The α-particle emission probabilities in the decay of 242Pu were measured using a surface-barrier detector in connection with a small magnet which eliminated most of the conversion electrons. The γ-ray emission probabilities were deduced from the γ-ray emission rates, measured with calibrated high-purity-Ge detectors, and the 242Pu disintegration rates, determined by α-particle counting in well-defined solid angles. For some of the sources they were also calculated from the 242Pu content measured by mass-spectrometric isotope dilution. The results obtained are: P α 0 = 0.7645 ± 0.0017, P α45 = 0.2352 ± 0.0017, P α148 = (2.90 ± 0.14)10 −4, P α307 = (8.6 ± 0.7)10 −6, P γ45 = (3.72 ± 0.07)10 −4, P γ103 = (2.63 ± 0.09)10 −5, P γ159 = (2.98 ± 0.20)10 −6. These results yield a consistent set of data with uncertainties being considerably smaller than those previously adopted.