CROSS-SECTIONS AND SPECTRA FOR (N,XP) AND (N,X-ALPHA) REACTIONS ON NI-58 AND NI-60 AT ENERGIES OF 9.4 AND 11 MEV

Cross sections and spectra for (n,xp) and (n,x alpha ) reactions on **5**8Ni and **6**0Ni at energies of 9. 4 and 11 MeV and for **5**8Ni at 8 MeV have been measured. This energy range spans the threshold for the (n,n prime p) reaction. Based on comparison of Hauser-Feshbach calculations with the measured spectra, this reaction provides a large fraction of the proton spectrum at 11 MeV for **5**8Ni. Both (n,xp) and (n,x alpha ) processes appear to be due largely to compound nuclear processes. Comparison of the measurements obtained here and those previously published at 15 MeV with calculations allows us to infer information about the nuclear level densities. Cross sections for (n,d) reactions are sufficiently small that only upper limits can be derived for them.