Cross-sections for the formation of Sb and Sc isotopes by irradiation of Y, La, Ta, and Au with 18·2 GeV protons

Abstract

The cross-sections have been measured for several Sb and Sc isotopes produced by irradiation of yttrium (Sc only), lanthanum, tantalum, and gold with 18·2 GeV protons. The shapes of the yield distribution curves for both Sb and Sc isotopes vary with the target element. If the previously known yield distributions with uranium as targets are decomposed into a “spallation” part and a fission part, the former will in both cases be about equal to the distribution with gold or tantalum as the target, whilst in shape the fission part closely resembles the distributions obtained when uranium is irradiated with 570–590 MeV protons. From the variation in shape of the distribution curves with target, this procedure of decomposition seems less justified for the scandium isotopes than for antimony isotopes. The high spin to low spin isomeric yield ratios of the 44Sc isomers were also determined, and show a very definite increase with mass difference between target and product.