Structure of Rubidium and Strontium Nuclides of Mass 90 and 91

Abstract

<p>The level structures of 90,91Rb and 90,91Sr, as populated in beta decay, have been investigated using Ge(Li) and NaI(Tl) gamma ray and plastic beta ray spectrometers, and standard spectroscopic techniques. Beta-gamma and gamma-gamma coincidence experiments have been used to establish twelve levels in 90Rb, four levels in 91Rb and to determine the ground state Q-values for the decay of both 90Kr and 91Kr. Thirty-one levels have been proposed in 90Sr and eighteen in 91Sr on the basis of gamma-gamma coincidence experiments only. The lifetime of the first excited state in 91Sr has also been measured.</p>