Beta decay of ⁹⁶Ag isomers and delayed proton emission to ⁹⁵Rh levels

Abstract

The decay of the neutron-deficient isotope ⁹⁶Ag was investigated by using a total absorption gamma-ray spectrometer (TAS) [1]. The aim of this study was to clarify the decay characteristics of the ⁹⁶Ag isomers which are predicted by shell-model calculation [2]. Some indication on isomerism in ⁹⁶Ag was obtained in a previous measurement [2], where different half-lives were obtained for β-delayed γ rays (βγ)and β-delayed protons (βp). TAS is well suited for this purpose as it is capable of detecting the whole γ cascade following β decay rather than individual γ transitions. Concerning the βp decay, a coincidence condition between a proton detector and TAS was used. ⁹⁶Ag was produced by fusion-evaporation reactions of a UNILAC with a ⁶⁰Ni target, and separated from other reaction products at the GSI on-line mass separator by using a chemically selective FEBIAD ion source. Our measurements reveal two β-decaying isomers of ⁹⁶Ag with half-lives of 4.35(8) s and 6.9(6) s. For both isomers, the apparent intensities of β decay to low-lying ⁹⁶Pd levels and βp decay to ⁹⁵Rh levels, I _β and I _βp, respectively, were measured as shown in Fig. 1. CRAP