Harold Stevenson Wilson
We have examined the a+ decays of eight ls-Od shell nuclei (26Si, 30P, 30S, 31S, 33Cl, 34Cl, 35Ar and 38Ca) by measuring the relative intensities of daughter γ rays with a large-volume high-resolution Ge (Li) detector. This work revealed the existence of seven previously unreported branches to excited states and established new limits for twenty-seven others. For 31S, 33Cl and 35Ar, as well as for 25Al, measurements of the absolute intensities of the excited state branches were made by normalizing γ-ray intensities to the intensity of 511-keV positron-annihilation radiation. Precise measurements of the half-lives of 26Si, 30S and 38Ca were also made and, combined with the results of the CVC theory, this provided an absolute normalization for the γ-ray intensities in these nuclei. In each case, the experimentally determined Gamow-Teller strengths are compared to the results of recent large-basis shell-model calculations. A general comparison of experimental and shell-model Gamow-Teller strengths for 1s-Od shell nuclei is made.