Isomeric yield ratios of 44Sc produced by the 14N bombardment of 32S and 31P

Abstract

Thick targets of red phosphorus and zinc sulphide were bombarded with 27·5 MeV 14N ions accelerated in the Oak Ridge 63 in. Cyclotron. Cross sections, as a function of the bombarding energy, were measured for the production of 43Sc, 44 m Sc, and 44 g Sc from 31P and 32S. The irradiated materials were γ-counted, and the radioactive products were identified by their characteristic γ-rays and half-lives. From the cross sections, the isomeric yield ratios of 44m Sc 44g Sc were found. For 31P the isomer ratio varied from 0·68 at 23·5 MeV to 1·68 at 27·0 MeV, while for 32S it varied from 0·12 at 20·5 MeV to 1·15 at 27·0 MeV. This increase in the ratio for both reactions is consistent with a compound nucleus formation mechanism for 44Sc at all energies considered. Accordingly, the higher ratio in the phosphorus reaction than in the sulphur reaction may be attributed to the smaller amount of angular momentum taken off by the single proton emitted from the 31P reaction than by the two protons emitted in the 32S case.