Excitation Functions for Spallation Products and Fission Isomers inNp237(He4,xn)241−xAm Reactions

Cross sections as a function of energy (19-46 MeV) have been measured for the following products from the reactions of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ with ${}_{}{}^{237}{}_{}{}^{}\mathrm{Np}$: ${}_{}{}^{237g}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{238g}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{238m}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{239g}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{239m}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{240g}{}_{}{}^{}\mathrm{Am}$. The prompt fission and total reaction cross sections have also been determined from 19 to 23 MeV. Isomer ratios as a function of excitation energy are presented for several fission isomers.