THE SPALLATION OF IRIDIUM WITH PROTONS OF ENERGIES 9–87 MEV

Abstract
Iridium metal has been bombarded with protons varying in energy from 8 to 87 Mev. The spallation products were radiochemically separated and decay characteristics and formation cross sections were determined. It was confirmed that both Pt187 and Pt186 have half-lives of about 3 hr, and a half-life of 13.3 ± 0.2 days was found for Ir189. An isomeric state of Ir186 with half-life 2.0 ± 0.5 hr has been found. Fair agreement was obtained between excitation functions for (p,xn) reactions determined experimentally and those predicted by the Jackson model. The (p,pn) yield at 84 Mev has been compared with that calculated from Monte Carlo cascade data combined with evaporation theory and found to be too high by a factor of 4.