In-beam gamma-ray spectroscopy of sup(66)Ga: Preliminary results

Abstract

The subject of this work is the experimental study of the odd-odd nucleus 66Ga produced with fusionevaporation reaction. To describe nuclei such as 66Ga, which has valence nucleons in the pf shells, the Large Scale Shell Model has been used with great success [1-6]. Odd-odd nuclei, however, are difficulty to describe theoretically and their experimental study gives new information about the nuclear structure and allows testing models parameterizations. The experimental study was performed using in-beam gamma-ray spectroscopy, where two experiments have been done: the first one with the fusion-evaporation reaction 58Ni(11B, 2pn)66Ga at 44 MeV bombarding energy and a target of about 1,0 mg/cm2 backed with 7,6 mg/cm2 of Pb and the second one with the 51V(19F, p3n)66Ga reaction at 54 MeV bombarding energy and two thin targets of about 400 µg/cm2 . The beam was provided by the 8UD Pelletron TANDEM accelerator of the Universidade de S˜ao Paulo, Brazil. Gamma-ray and evaporated charged particle coincidences were measured with the SACI-PERERE γ-ray spectrometer [7], composed of a 4π-charged particle system consisting of 11 phoswich scintillator ∆E-E telescopes and 4 Compton-suppressed GeHP, two of them with an efficiency of 60% and the other two with an efficiency of 20%. The 58Ni(11B, 2pn)66Ga reaction, however, was performed using only the two 60% GeHP detectors. About 4x106 and 60x106 gamma-gamma events were collected in the 58Ni(11B, 2pn)66Ga and 51V(19F, p3n)66Ga, respectively. Preliminary results have confirmed part of the known level scheme for 66Ga