Estimation of the spallation-residue angular momentum in p+Ta, Re reactions

Yields and cross-sections for the radioactive isotope production have been determined via gamma-activity measurements after irradiation of the Ta and Re targets by protons with energies from 100 to 660 MeV. Mass distribution of the reaction products contains two wide peaks corresponding to the spallation and fission product nuclei, respectively. High-spin Hf and Lu isomers are among the detected nuclides. The spallation-residue angular momentum I has been estimated basing on the determined isomer-to-ground state ratio sigma sub m /sigma sub g versus I. Nonzero value of spin I should increase the probability of fission. The measured fission-to-spallation ratio is indeed higher than that predicted by the Monte Carlo code simulation without angular momentum in account