Cross Sections for Formation ofNa22from Aluminum and Magnesium Bombarded with Protons

Cross sections for formation of ${\mathrm{Na}}^{22}$ from proton bombardment of aluminum and magnesium have been determined for the energy range from thresholds to 32 Mev. The ${\mathrm{Al}}^{27}(p, p\alpha n){\mathrm{Na}}^{22}$ reaction has a threshold of 25 Mev and the cross section for the reaction rises to a value of 2.5 millibarn at 32 Mev. The cross section for the production of ${\mathrm{Na}}^{22}$ from magnesium has a value of 0.25 millibarn at 10 Mev, rises through a maximum of 9 millibarns at 17 Mev, drops to a minimum of 5 millibarns at 23 Mev and then rises to a value of 19 millibarns at 32 Mev.