Properties and structure of 7476Br from the 7476Se(p,n) reaction

Targets of selenium metal enriched to 78.61 percent in 74Se and 86.10 percent in 76Se were bombarded with protons from a 15 MeV FN Tandem Van de Graaff accelerator. Proton energies were 5.8-9.0 MeV. Threshold energies for the 74Se(p,n)74Br and 76Se(p,n)76Br reactions were determined by examining excitation functions obtained with a 3 mm thick (Si(Li)) detector and a 30cc Ge(Li) detector. Verification of the threshold for the 74Se(p,n) reaction were made by analysis of the beam-off gamma-ray spectra of the decay of the residual nuclei. Threshold results were used to deduce 74,76Br mass excesses and these were compared to theoretical predictions. Subsequent to determination of the reaction thresholds, the gamma-ray spectra, taken in 10-25 keV steps up to 700 keV above threshold, were analyzed through threshold behavior and energy sums to construct a level scheme. Two Ge(Li) detectors were used for γ-γ coincidence measurements and the data was analyzed to complete the 74Br and 76Br level schemes. Level schemes were compared to schemes developed through other reactions. (U.S.)