LEVELS OF 69GA AND 71GA VIA (N,N'GAMMA) REACTIONS

Differential cross sections for the production of γ rays in the Ga(n,n′γ) reactions have been measured at 90°as a function of incident energy for 0.4≤En≤2.5 MeV. Angular distributions at En=0.650,0.800,1.50,and 1.78 MeV have also been measured. Level schemes and decay schemes including branching ratios have been determined. An earlier scheme for Ga69 is confirmed, and two new levels are found. The level scheme of Ga71 is defined for excitation energies below 2 MeV. From the γ-ray angular distributions and neutron inelastic scattering cross sections, spins have been determined for five levels in each isotope. When these and other measurements are combined, the following excitation energies in keV, spins, and parities result. In Ga69: 319(1/2-), 573(52-), 873(32-), 1027, 1108(≤52) 1334(72), 1527, 1724, and 1893. In Ga71: 390(1/2-), 487(52-), 512(32-), 911(12-,32-), 965(72), 1108(72-), 1474, 1487, 1495(92+), 1700, and 1750. © 1969 The American Physical Society.