The electron capture to positron branching ratio in the decay of 22Na

Abstract

A new measurement has been made of the electron capture to positron branching ratio (e/β+) in the decay of 22Na to the 1.27 MeV level in 22Ne. The measurement was made using 4πβ–γ coincidence counting with a pressurized 4π-proportional β-detector and efficiency variation techniques. The value of 0.1077 ± 0.0006 obtained for the e/β+ ratio is about 3% larger than other precise values and is compared with recent theoretical estimates.