Isomerism in 96Ag and non-yrast levels in 96Pd and 95Rh, studied in β decay

Abstract

The β decay of 96Ag ( Z=47, N=49) was investigated by measuring positrons, X rays as well as β-delayed protons and γ rays. The γ radiation was studied by means of germanium detectors and a NaI total-absorption spectrometer. Two β-decaying isomers in 96Ag were established with half-lives of 4.40(6) and 6.9(6) s and tentative spin–parity assignments of (8 +) and (2 +), respectively. For both isomers, the intensities of β transitions to low-lying levels of 96Pd ( Z=46, N=50) and β-delayed proton decays to levels in 95Rh ( Z=45, N=50) were measured. Several new 96Pd levels were firmly established. The level energies, their γ decays and the Gamow–Teller decay of 96Ag are compared to shell-model predictions. A new low-lying level in 95Rh was found at 680 keV excitation energy. Through a comparison with low-lying states of N=50 isotones, this level is interpreted as the first excited 7/2 + state built on the proton 9/2 + ground state. The assignments of further excited states in 95Rh are discussed.