Possible deformed states in 115In and 117In

Abstract

Levels and transitions in 115In and 117In have been studied from the beta decay of 2.3 d 115gCd and 2.5 h 117gCd. Using a Ge(Li) detector and a double focussing beta spectrometer, energies, intensities, conversion coefficients and multipolarities were obtained for the following transitions (energies in keV and multipolarities are given): 115In: 35.63 (97.0% M1 + 3.0% E2), 231.47 (E1), 260.80 (M1), 267, 336.23 (M4+< 5% E5), 492.14 (96% E1 + 4% M2), 527.70 (E1). 117In: 71.0, 89.80 (E2+< 20% M1), 273.32 (M1, E2), 315.27 (M4+<7% E2), 344.29 (E1), 434.12 (E1). Using the delayed coincidence technique, half-lives were measured for two levels in 115In and for three levels in 117In. Energies, spins, parities and half-lives are given for the following levels: 115In: 597.03, 3 2 − ; 828.39, 3 2 + , 5.4 ns; 863.95, 1 2 + or 3 2 + , 1.1 ns. 117In: 588.59, 3 2 − ; 0.20 ns; 659.56, 3 2 + , 58.7 ns; 749.37, 1 2 + or 3 2 + , 4.3 ns. Reduced transition probabilities are given for several transitions in both nuclei. The E2 transition rates between the two excited positive parity states in both nuclei were found to be about 100 s.p.u. indicating a possible deformation of these states. The energy spacing and transition rates between these states can be well accounted for within the Nilsson model assuming the states to form a K = 1 2 + rotational band. A deformation δ of about 0.20 is obtained for both nuclei.