Electron-Induced Preequilibrium Alpha Emission

Abstract

This paper presents energy spectra of $\ensuremath{\alpha}$ particles emitted following the bombardment of $^{27}\mathrm{Al}$, $^{\mathrm{nat}}\mathrm{Ni}$, $^{92}\mathrm{Mo}$, $^{94}\mathrm{Mo}$, and $^{197}\mathrm{Au}$ with 120-MeV electrons, together with $\ensuremath{\alpha}$-particle angular distributions from $^{197}\mathrm{Au}$ and $^{\mathrm{nat}}\mathrm{Ni}$ for ${E}_{\ensuremath{\alpha}}=30 \mathrm{and} 50$ MeV. The data are compared with preequilibrium exciton-model and statistical-model calculations. It is concluded that few-step processes are dominant in the production of $\ensuremath{\alpha}$ particles with energies above 20 MeV.