The shape of the intense Au 198 beta spectrum and the K conversion coefficient of the 412-keV transition

Abstract

The intense beta spectrum of Au 198 and the K internal conversion coefficient of the 412-keV transition were measured. The beta spectrum was found to have a non-statistical shape which can be best fitted with a once-forbidden shape factor of the form 1−0.33 W + 0.074 W 2. With this shape factor used to determine the total intensity of the beta spectrum and thereby the intensity of the gamma radiation, the K internal conversion coefficient of the 412-keV transition in Hg 198 is found to be α K = (282 ± 10) × 10 -4. On the basis of a statistical shape for the beta spectrum, a value of 297 × 10 −4 would be obtained.