Threshold reaction cross sections of nickel isotopes, averaged over a U-235 fission neutron spectrum

We have measured, for nickel isotopes, several threshold reaction cross sec tions averaged over a U-235 fission neutron spectrum. The measured reaction s, and corresponding averaged cross sections found, are the following: Ni-6 0(n,p)Co-60m, 1.499 +/- 0.083 mb; Ni-61(n,p)Co-61, 1.632 +/- 0.096 mb; Ni-5 8(n,2n)Ni-57, 4.72 +/- 0.26 mub; Ni-58(n, d+np +pn)Co-57, 275 +/- 15,mub; N i-58(n, p)Co-58g, 74.8 +/- 2.3 mb; and Ni-58 (n, p)(58m) Co, 36.6 +/- 1.2 m b; all referred to the well-known standard of 111 +/- 3 mb for the Ni-58 (n , p)Co58m+g-averaged cross section. The measured cross sections are of inte rest in nuclear engineering for the characterization of the fast neutron co mponent in the energy distribution of reactor neutrons.