A Study of the 42Ca(p,?)43Sc Reaction

Abstract

The 42Ca(p, y)43SC reaction has been studied below 2·75 MeV proton bombarding energy. Approximately 100 resonances have been identified and located in the range Ep = 2·00-2·75 MeV. Nine resonances at Ep = 1045, 1201, 1299, 1319, 2038, 2471, 2523, 2643 and 2714 keV for the 42Ca(p, y)43SC reaction were investigated with either a 54 or a 120 cm3 Ge(Li) detector. Single spectra were obtained at each of these resonances, and these were used to derive consistent y ray decay schemes and accurate level energies for the resonant and bound levels of 43Sc. Fifty-two bound levels up to an excitation energy of 4·47 MeV were observed, out of which seventeen new levels have been identified at 2·114,2· 796,2' 846,2' 860,2' 875,3 '160,3' 331,3' 374,3 '463,3;504,3' 645, 3'734,3'757,3'860,4'007,4'038 and 4·430 MeV. In addition, new results or results differing from earlier reports have been obtained for the decay properties of levels below 4·47 MeV in 43SC? The strengths of the nine resonances were measured relative to the reported strength at Ep = 2038 keV. The resonance at Ep = 2643 keV was shown for the first time to populate levels of spin> 7/2 via the proton capture reaction. A strong M1 (analogue to anti-analogue) transition from the resonance level to the level at 1· 931 MeV (9/2+) was observed. From measurements of y ray angular distributions, the following spin and parity assignments were made: 9/2+ at 7'514, 7/2+ at 4'371, >7/2 at 4'038 and 7/2 at 3·808 MeV. The resonance level at 7·514 MeV has possibly aT = 3/2 character. The low-lying excited states in 43SC are in reasonable agreement with the theoretical predictions of Johnstone (1968).