Properties of the 612 keV Resonance in the 27Al(p,γ)28Si Reaction

Abstract

Gamma rays from the resonance at Ep = 612 keV in the 27Al(p,γ)28Si reaction have been studied using a 40 cm3 Ge(Li) counter. Doppler shift measurements on the primary gamma ray show (85 ± 3)% of the expected full shift, indicating a lifetime of 13 ± 3 fs for the resonance level. A good parameterless fit to the 12angular correlation coefficients obtained by Heyligers suggests a spin of 5 for the resonance as an alternative to the previously considered values of 2, 3, and 4. A weak 2% decay from the 12 174 keV resonance level to the 3+ level at 8586 keV has been observed, and the E2/M1 mixing ratio for the decay from the 6276 keV, 3+ level to the 4617 keV, 4+ level has been obtained. A Q value for the 27Al(p,γ)28Si reaction of 11 584.1 ± 1.5 keV has been measured.