Gamma Branching in Kr⁸⁵

Kr⁸⁵ decays directly to the ground state by 0.67-Mev maximum beta emission in greater than 99% of the decay. The fraction of the decay which proceeds through a lower energy beta emission (∼0.16 Mev) followed by a gamma transition of 0.514 Mev has been determined by measurement of the number of 0.513-Mev gamma rays per beta disintegration. This γ/β ratio measured by γ scintillation spectrometry and absolute beta counting techniques was found to be 0.0038 ± 0.0003.