High resolution Gamow-Teller strength measurement via β-decay of 65Ge

The β+ decay of 65Ge was studied by β-delayed proton and γ-ray emission. The He-jet technique was used. Altogether 28 proton groups (1.0 MeV<Ep<2.1 MeV) were observed with proton energy resolution of about 10 keV. The proton spectrum apparently consists of discrete proton groups due to a selective population of excited states of 65Ga by Gamow-Teller β+ decay. The total proton branching ratio was measured to be (1.1±0.3)x10-4. Upper limit of log ft values for beta transitions associated with the observed delayed proton groups and γ-rays were calculated and an experimental beta transition strength function was obtained. The single level structure of 65Ga was studied by the 64Zn(p, γ)65Ga resonance reaction in the proton energy range 1.1 MeV<Ep<2.1 MeV with 1.0 keV overall energy resolution and about 170 resonance levels were observed. Angular distribution and resonance decay measurements were done to study the nature of selected single levels and decay properties of low energy levels. The proton binding energy of 65Ga was measured to be Bp=3943.0±1.0 keV. (orig.)