Correction factors for γ-ray relative intensities in the 66Ga radioisotope

Abstract

We present here strong evidence that recently published values for the relative intensities of γ-ray lines in the 66 Ga(β + + EC) 66 Zn decay are incorrect at the higher energies (∼ 30% too low at 4.8 MeV). In particular, we find that our current results are consistent with a set of correction factors which were first suggested 20 years ago, but have gone largely ignored until now. Our validation of these little known correction factors will have bearing on experiments which use the 66 Ga radioisotope to extrapolate absolute detector efficiencies to higher energies. In particular, we discuss the conclusions of a recent D(p, γ ) 3 He experiment which will be strongly affected by our current results. The astrophysical S -factor data derived from this D(p, γ ) 3 He experiment are now seen to be systematically too low by ∼ 30%.