Study of theAl27(α, Be7)Na24Reaction from Threshold to 41 MeV

Abstract

Excitation functions for the formation of ${\mathrm{Na}}^{24}$, ${\mathrm{Be}}^7$, and ${\mathrm{Na}}^{22}$ in the interaction of ${\mathrm{Al}}^{27}$ with alpha particles have been measured from threshold to 41 MeV. The cross sections at 41.2 MeV are 0.33, 0.14, and 8.0 mb, respectively, and the excitation functions exhibit a sharp rise with bombarding energy. The recoil properties of the above nuclides have been investigated by means of thick-target integral range measurements at 40 MeV. The results for ${\mathrm{Be}}^7$ are consistent with approximately equal contributions from direct interaction and evaporation processes while the results for ${\mathrm{Na}}^{24}$ and ${\mathrm{Na}}^{22}$ indicate that these nuclides are primarily formed through processes involving compound-nucleus formation. It is concluded that at 40 MeV approximately 60% of the yield of ${\mathrm{Na}}^{24}$ may be attributed to the ($\alpha , \alpha {\mathrm{He}}^3$) reaction.