Measured Thermal-Neutron Cross Section for the ⁵⁹Ni(n, α)⁵⁶Fe Reaction

Deviations from normal mechanical properties observed in stainless steel irradiated by neutrons have been attributed to the production of helium in neutron reactions with nickel. A measurement of the thermal-neutron cross section for the ⁵⁹Ni(n,α)⁵⁶Fe reaction has been made in which the alpha-particle emission was determined by a silicon surface-barrier particle spectrometer. The 2200 m/sec cross section obtained is 18.0±1.6 b. This value disagrees with 13.7 ± 0.6 b reported earlier by Eiland and Kirouac.