Compound-nucleus contribution to (α, α') reactions in Ni, Zn, and Sn

A clean separation of compound nucleus from noncompound nucleus processes in (α, α') reactions is made for 18-MeV α-particles on Ni, Zn, and Sn. Experimental results agree well with both Weisskopf and Hauser-Feshbach theory using Gilbert-Cameron level densities. In addition, a surprising theoretical prediction in the case of Ni is dramatically confirmed by experiment. NUCLEAR REACTIONS ^58,60,62Ni(α, α'), ^64,66Zn(α, α'), ¹¹²Sn(α, α'), E=18 MeV; measured d²σdΩdE, deduced compound-nucleus contribution to cross section, compared with calculations from Weisskopf, Hauser-Feshbach statistical theory.