K-Electron Capture Branch ofSr87m

Abstract

The existence of a (0.65±0.25)% $K$-electron capture branch in the decay of 2.8-hr ${\mathrm{Sr}}^{87m}$ has been established by means of an "internal source" technique. The low $logft=4.25\mathrm{}$ and small energy release of 115 kev make this $K$ branch especially interesting because it establishes ${\mathrm{Rb}}^{87}$ as a possible low-threshold detector for the inverse neutrino capture reaction, ${\mathrm{Rb}}^{87}+\nu \to {\mathrm{Sr}}^{87m}+e^{-}$, which could be identified by observing the characteristic decay of the ${\mathrm{Sr}}^{87m}$ isomer.