Protons from Alpha-Induced Reactions

Abstract

The results of proton energy spectra measured at several angles from 30.5-Mev alpha particle induced reactions on ${\mathrm{Al}}^{27}$, ${\mathrm{V}}^{51}$, ${\mathrm{Co}}^{59}$, ${\mathrm{As}}^{75}$, ${\mathrm{Nb}}^{93}$, ${\mathrm{Rh}}^{103}$, ${\mathrm{In}}^{115}$, and ${\mathrm{Ta}}^{181}$ were analyzed using the statistical model. The analysis yielded the differential cross section $\frac{d^2\sigma }{d\Omega \mathrm{dE}}$ and the relative level density $\omega \mathrm{}\left(E\right)\mathrm{}$ of the residual nucleus as a function of proton and excitation energy of the residual nucleus. The nuclear temperature $\frac{1}{T}\equiv \frac{d\left(\ln \omega \right)}{\mathrm{dE}}$ and the level density parameter $a$ of $\omega =C\exp \left[{\mathrm{}\left(\mathrm{aE}\right)\mathrm{}}^{\frac{1}{2}}\right]$ were obtained. The energy and angular dependence of the spectra are adequately described by the statistical model at back angles, with the indication of the presence of a direct-reaction mechanism contribution at forward angles, which extends to high excitation energies.