Surface barrier detectors at 16-18 angles measured simultaneously the differential cross sections for the reactions ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$($\alpha$,${\alpha }_0{\alpha }_1{\alpha }_2{\alpha }_3{\alpha }_4{\alpha }_5$)${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ in the bombarding energy range from 14.6 to 20.4 MeV and in steps of 10 keV. For $E_{\alpha }>18\mathrm{}$ MeV peak fitting techniques separated the yields of ${\alpha }_1$ ($Q=-6.05\mathrm{}$ MeV) from ${\alpha }_2$ ($Q=-6.13\mathrm{}$ MeV). The target was a differentially pumped windowless gas target of high purity ${\mathrm{O}}_2$. A total of 25 levels in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ ($16<\mathrm{}{E}_x<21\mathrm{}$ MeV) were analyzed by writing the reaction amplitude for spinless positive-parity particles as a nonresonant term which varies linearly with energy plus a sum over only resonant partial waves. Inelastic scattering angular distributions were expanded in terms of Legendre polynomials for $E_{\alpha }>18\mathrm{}$ MeV.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$($\alpha$,${\alpha }_0{\alpha }_1{\alpha }_2{\alpha }_3{\alpha }_4{\alpha }_5$)${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, $14.6<~E_{\alpha }<~20.4$ MeV, $\Delta E_{\alpha }=10\mathrm{}$ keV; measured $\sigma (E,\theta )$ at 18 angles. Deduced ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ level parameters $J$, $\pi$, ${\Gamma }_{{\alpha }_0}$, ${\Gamma }_{{\alpha }_1}$, $\Gamma$, $E_R$. ${\mathrm{O}}_2$ gas target.

• Received 18 June 1979

DOI:https://doi.org/10.1103/PhysRevC.20.1648