InverseαDecay via the ReactionPb208(O16,C12)Po212

Abstract

We have measured the reaction ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ at $E_{{}_{}{}^{16}{}_{}{}^{}\mathrm{O}}=93\mathrm{}$ MeV; the peak cross sections leading to the ground and first excited states of ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ are 750 and 1750 nb/sr, respectively. The reaction mechanism appears to be direct and excellent distorted-wave Born-approximation fits to the data yield a spectroscopic ratio of $\frac{S(0.727\mathrm{} \mathrm{MeV}, 2^{+})}{S(\mathrm{g}.\mathrm{s}.\mathrm{})}=0.64\mathrm{}\pm 0.13$ in good agreement with the value 0.61±0.24 derived from ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ $\alpha$ decay. Preliminary attempts at obtaining absolute α widths yield ${{\gamma }_{\alpha }}^2\left({}_{}{}^{212}{}_{}{}^{}\mathrm{Po}\right(\mathrm{g}.\mathrm{s}.\mathrm{}\left)\right)\sim 1.4$ keV from both $\alpha$ decay and the transfer reaction.