Angular correlation and lifetime measurements inNe22

Abstract

Particle-$\ensuremath{\gamma}$ angular correlations have been measured for a number of states above 7.3 MeV in $^{22}\mathrm{Ne}$ using the $^{18}\mathrm{O}(^{7}\mathrm{Li},t\ensuremath{\gamma})^{22}\mathrm{Ne}$ reaction with the tritons observed at 0\ifmmode^\circ\else\textdegree\fi{}. New information on the spins and parities of several states in $^{22}\mathrm{Ne}$ was obtained. In addition, by demonstrating that the $^{22}\mathrm{Ne}$ nuclei were strongly aligned, these measurements provide support for a direct $\ensuremath{\alpha}$-particle transfer mechanism for the $^{18}\mathrm{O}(^{7}\mathrm{Li},t)^{22}\mathrm{Ne}$ reaction. Angular correlation and lifetime measurements employing the $^{19}\mathrm{F}(\ensuremath{\alpha},p\ensuremath{\gamma})^{22}\mathrm{Ne}$ reaction have also been performed for a number of states in $^{22}\mathrm{Ne}$, including several closely spaced doublets on which previous information is incomplete or inconsistent. Lifetimes were measured by the Doppler-shift attenuation method. The results are compared with recent large basis shell model calculations.NUCLEAR REACTIONS $^{18}\mathrm{O}(^{7}\mathrm{Li},t\ensuremath{\gamma})$, $E=12.0$ MeV; $^{19}\mathrm{F}(\ensuremath{\alpha},p\ensuremath{\gamma})$, $E=12.0, 15.0, 18.5, 19.0$ MeV; measured $t\ensuremath{-}\ensuremath{\gamma}$, $p\ensuremath{-}\ensuremath{\gamma}$ angular correlations, Doppler-shift attenuation. $^{22}\mathrm{Ne}$ deduced levels, $\ensuremath{\tau}$, $J$, $\ensuremath{\pi}$, $B(\ensuremath{\Lambda})$.