Some Neutron Deficient Strontium Isotopes

Abstract

Bombardment of rubidium with protons produced ${\mathrm{Sr}}^{81}$, half-life 29 minutes, ${\mathrm{Sr}}^{82}$, half-life 25 days, and ${\mathrm{Sr}}^{83}$, half-life 38 hours. ${\mathrm{Sr}}^{81}$ and ${\mathrm{Sr}}^{83}$ are assigned on the basis of their positron decay to known ${\mathrm{Rb}}^{81}$ and ${\mathrm{Rb}}^{83}$, respectively. The half-life of ${\mathrm{Rb}}^{83}$ has been redetermined as 83 days, and it has been shown that it decays in part to the 1.8-hour ${\mathrm{Kr}}^{83m}$. ${\mathrm{Sr}}^{82}$ probably decays by electron capture to a short-lived isomer of ${\mathrm{Rb}}^{82}$, which in turn decays by emission of 3.15-Mev positrons. In this case, the mass assignment is based on the energy required to produce the activity in a bombardment, because the known ${\mathrm{Rb}}^{82}$ was not observed as a decay product.