The width of the 12.291 MeV level of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ was measured by the axial blocking of $\alpha$ particles from the ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$($p$,${\alpha }_0$) resonance at $E_p=731.4\mathrm{}$ keV. The result $\Gamma ={28}_{-6\mathrm{}}^{+13\mathrm{}}$ eV compares very favorably with that obtained from yield measurements but not with a previous planar blocking experiment.

NUCLEAR REACTIONS ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$($p$,${\alpha }_0$)${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, $E=0.731\mathrm{}$ MeV; measured blocking effect. ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ deduced level width. Single crystal thick Al targets. LR 115 cellulose nitrate detectors.

• Received 28 September 1979

DOI:https://doi.org/10.1103/PhysRevC.21.1646