Angular Distribution of Gamma Rays from Proton Capture inB11

Abstract

The $\gamma$-ray yield at 90° from the bombardment of ${\mathrm{B}}^{11}$ by protons shows resonances for proton energies of 0.67, 1.4, and 2.7 Mev. The angular distributions of the two $\gamma$ rays of high energy, ${\gamma }_0\sim 17$ Mev and ${\gamma }_1\sim 12$ Mev, have been measured at these resonances to obtain evidence concerning the spins and parities of the excited nucleus. The evidence favors 2- for the 0.67-Mev resonance, 1- for that at 1.4 Mev, and 2+ at 2.7 Mev, but these assignments cannot be made with certainty.