Positive pion production from the bombardment ofBe9with 200, 225, and 250 MeV polarized protons

The analyzing power angular distributions $A_y\left(\theta \right)$ for the ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$ as well as the ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}_{3.37}^{}{}_{}{}^{}$* state transitions from the ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$($\overrightarrow{p}$,${\pi }^{+}$)${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ reaction are reported as a function of incident proton energy from 200 to 250 MeV. Instead of the dramatic dependence on energy characterizing the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($\overrightarrow{p}$,${\pi }^{+}$)${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ reaction, the analyzing power for the present reaction shows little variation with energy. At energies above 200 MeV the analyzing power angular distributions exhibited by the ($\overrightarrow{p}$,${\pi }^{+}$) reactions on ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ are markedly different, unlike the earlier observations at 200 MeV where the distribution was essentially the same.