Polarization of the Gamma Rays in theF19(p, αγ)O16Reaction

Abstract

The polarizations of the 6.13-, 6.9-, and 7.1-Mev gamma rays from the ${\mathrm{F}}^{19}(p, \alpha ){\mathrm{O}}^{16*}\left(\gamma \right){\mathrm{O}}^{16}$, $E_p=0.87\mathrm{}$ Mev, reaction have been observed using the photodisintegration of the deuteron to detect polarization. Range measurements on the photoprotons separated the 6.13-Mev gamma ray from the other two, which were only slightly resolved. Knowing the relative intensities of the 6.9- and 7.1-Mev gamma rays and their unresolved angular distribution coefficient, it is possible, nevertheless, to deduce the separate polarizations from the observed total polarization. Polarization ratios, $\frac{I\left(0\mathrm{}°\right)}{I\left(90\mathrm{}°\right)}$, of 0.9±0.1, 1.9±0.3, and 0.4±0.3 were obtained for the 6.13-, 6.9-, and 7.1-Mev gamma rays, respectively, emitted at 90° to the proton beam. These values are in good agreement with the polarizations expected for the assignment of a $2^{-}$ state in ${\mathrm{Ne}}^{20}$ and $3^{-}$, $2^{+}$, and $1^{-}$ states in ${\mathrm{O}}^{16}$ as deduced by Seed and French from directional correlation measurements on this reaction.