Simple Nuclear Reactions ofGa69andGa71with High-Energy Protons

Excitation functions in the energy range of 0.5-2.9 Bev have been measured for several ($p, \mathrm{xn}$), ($p, \mathrm{pxn}$), and ($p, 3pxn$) reactions of ${\mathrm{Ga}}^{69}$ and ${\mathrm{Ga}}^{71}$. The cross-section for the ($p, \mathrm{pn}$) reactions are about 57 mb at 2.9 Bev and 69 mb at 0.5 Bev. The cross sections for the ($p, \mathrm{pxn}$) reactions decrease monotonically as $x$ increases and are some 30-250 times larger than the isobaric ($p, \mathrm{xn}$) reaction cross sections. The results are compared with Monte Carlo cascade and evaporation calculations. Good agreement is obtained at 0.5 Bev except in the case of the ($p, \mathrm{pn}$) reaction. In the Bev region the agreement is less widespread. The ($p, \mathrm{pn}$) cross-sections are compared with a calculation that takes the effects of shell structure and a diffuse nuclear surface into account. Some preliminary conclusions about the availability of the $1f_{\frac{7}{2}}$ shell for ($p, \mathrm{pn}$) reactions in this mass region are drawn on the basis of this comparison.