Reactions of Nickel with Alpha-Particles

Abstract

Excitation functions for the alpha-particle induced reactions on Ni⁵⁸, Ni⁶⁰, Ni⁶¹, Ni⁶² and Ni⁶⁴ have been measured at incident energies up to 40 Mev. The sum of the measured cross sections for Ni⁵⁸ appears to agree with the total reaction cross section calculated from the continuum theory for r₀=1.7×10⁻¹³ cm. The sum almost agrees with the optical-model analysis of reaction cross section for alpha-particles by Igo, but his prediction seems to give a little higher value. In the excitation function for the (α, αn) reaction on Ni⁵⁸, there is a small “knee” immediately after the effective threshold (around 23 Mev). The alpha-particle reactions on Ni⁶⁰ have been compared with the proton reactions on Cu⁶³, the compound nucleus Zn⁶⁴ being the same for two cases. The prediction from the compound nucleus theory seems to hold roughly, and it seems inadequate to discuss strictly whether the discrepancy in energy is significant. The same is observed in the comparison between the alpha-particle reactions on Ni⁶² and the proton reactions on Cu⁶⁵.