Direct measurement of the ${}^7$Be $L/K$ capture ratio in Ta-based superconducting tunnel junctions

S. Fretwell, K. G. Leach, C. Bray +8

We report a high-statistics measurement of the $L/K$ orbital electron capture (EC) ratio in ${}^7$Be embedded in cryogenic Ta. The thin Ta film formed part of a high-resolution super…