(p, xn) and (p, pxn) Reactions of Yttrium-89 with 5-85-MeV Protons

Abstract

Excitation functions for the ($p, \mathrm{xn}$) ($x=1-4\mathrm{}$) and ($p, \mathrm{pxn}$) ($x=1-5\mathrm{}$) reactions of ${\mathrm{Y}}^{89}$ with 5-85 MeV protons have been determined. Isomer ratios have been measured for the ($p, p2n$), ($p, p3n$), and ($p, p4n$) reactions. The cross sections have been compared with the results of a cascade-evaporation calculation based on the recent code by Chen et al. This calculation predicts close to 100% compound-nucleus formation up to bombarding energies of about 35 MeV, and the excellent agreement with experiment attests to the validity of this prediction. A number of discrepancies between experiment and calculation are noted at higher energies. These are due to the fact that the calculation by Chen et al. appears to overestimate the amount of compound-nucleus formation in the energy range of 45-85 MeV.