Gamma-ray spectroscopy of89Nb

Abstract

The structure of the N=48 nucleus S9Nb has been studied using in-beam y-ray spectroscopy following a number of reactions. Several levels with spins between 15/2 and 25/2 are identified. The results are discussed in terms of the shell model.

Shell model studies in89Nb

“…Where more than one decay mode is available for a level, the branching ratios for that level decay are obtained with respect to one of the decay channels with a branching ratio = 1.0 (not shown). The dashed levels correspond to our predictions for the states of unidentified spins at 2.7282 MeV and 2.5237 MeV reported by Diana et al in reference [4] (21/2---,21/2+))=12.1 is obtained in the decay of the 21/2 state. This rules out the observed dipole transition involving this level.…”

“…IV. Diana et al [4], and Fields et al [11], had suggested the possibilities of shell model structures, respectively, for the levels in S9Nb, and for some of the low-lying levels in svy. The latter suggestion came about because of the failure of the quasiparticle-phonon study of Krishan and Sen [8] on avy.…”

“…There is a need to explain the considerable experimental data [1][2][3][4] that have become available on the nucleus 89Nb in recent years. In the general, nuclei near the strong N= 50 shell closure and the Z=38 subshell closure have been fairly well described in terms of the nuclear shell model scheme [5][6][7].…”

Multiplet structure and core-related effects on transition rates in87Y and neighbouringA? 90 nuclei

“…Seniority-three 21/2 + isomers were earlier observed in neighbouring nuclei with N = 50 [6], N = 49 [7][8][9] and N=48 [10]. It seems to be of interest to extend this systematics also to 87y.…”

High-spin states in89Nb,88Zr and88Nb with a shell-model description of theN=48 andN=47 nuclei

“…In these studies, only a few low-lying states have been assigned J~ values. More recently, states in SgNb have been studied by Diana et al [8] using the 9~ 2n7), 9~ p3nT) and s9y(3He, 3ny) reactions. They have identified and assigned d ~ values to several higher-lying levels.…”