Study of the energy levels of Ga69 using nuclear photoexcitation

Elastic and inelastic scattering of monochromatic photons were used for studying nuclear energy levels in Ga69; the photons were produced by thermal neutron capture in copper and vanadium. The decay of one resonance at 7306 keV excited by the copper γ source and another resonance at 6874 keV excited by the vanadium γ source were studied in detail and 30 low-lying levels were observed from the ground state up to 3.4 MeV, 17 of which are believed to be new levels in Ga69. The angular distribution of some elastic and inelastic lines were measured and the following spin determinations were made (keV, Jπ): 320, 12-, (32-); 574, 52-; 872, 32-; 1488, 32-, 72-; 1525 (1/2, 32); 1891, 32- (1978), (1/2, 32); 2457, 32; 2484, 52; (2565), (1/2, 32); 2660, 32; 3051, (32, 72); 3076, 52; 3318, (72); 6874, 12(+) and 7306, 52+, where parentheses denote uncertain Jπ assignments. The parity of the 7306-keV level was directly determined using a Compton polarimeter. The total radiative width of the 7306-keV level was measured and found to be Γ=0.105±0.020 eV. For the 6874-keV level, a positive correlation coefficient was obtained, ρ=0.69, between the (γ,γ′) and (d,n) transition strengths leading to the same final states in Ga69. The levels of Ga69 are compared with recent theoretical calculations.