The γ-ray decay properties of low-lying levels of 65Zn via the 65Cu(p, nγ)65Zn reaction

Abstract

They γ-ray decay of 13 low-lying levels of 65Zn has been studied utilizing the 65Cu(p, nγ)65Zn reaction. The decay scheme was obtained from θγ = 90° yield curve measurements and from a neutron-gamma coincidence measurement. Angular distributions γ-rays were measured for seven angles at Ep = 3.5 and 4.0 MeV. Gamma-ray energies, level energies, and branching ratios obtained are compared with recent measurements. Expected angular correlations for possible spin sequences are calculated utilizing Hauser-Feshbach statistical reaction theory. The results, combined with other available evidence, establish the Jπ assignments for the following levels: 768.9 ± 0.1 keV (52−), 864.8 ± 0.2 (72−), 1047.5 ± 0.1 (52−), 1252.9 ± 0.4 (72 and 1343.9 ± 0.1 (52−). Previous assignments are confirmed for the levels 909.8 ± 0.1 keV (32−) and 1369.5 ± 0.2 (52+). Limiting ifJ-values are obtained for the levels of 1577.1 ± 0.2 keV (≦ 52) and 1588.2 ± 0.4 (≦ 72). Gamma-ray multipole mixing ratios are extracted for 19 transitions between low-lying levels and transition strengths calculated where the level lifetimes are assumed to be in the range 10−12 to 10−13 sec.