High-spin states in the odd-odd nucleus ${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$

The properties of high-spin states in ${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$, including three isomers, have been studied with the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^7{}_{}{}^{}\mathrm{Li}$,$3n$)${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$ reaction. In-beam measurements with Ge(Li) and intrinsic Ge detectors of $\gamma$-ray excitation functions, $\gamma -\gamma$ coincidences, $\gamma$-ray angular distributions, pulsed-beam-$\gamma$ timing, and perturbed angular distributions with an applied magnetic field were made to establish a decay scheme, level energies, $\gamma$-ray multipolarities, spin-parity assignments, isomeric lifetimes, and $g$ factors. High-spin states up to $15\hslash$ were identified as predominantly three proton [${\left(\pi h_{\frac{9}{2}}\right)}^3$ or ${\left(\pi h_{\frac{9}{2}}\right)}^2$ ($\pi i_{\frac{13}{2}}$)] states of the ($N=126\mathrm{}$) ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ nucleus coupled to a neutron in either the $g_{\frac{9}{2}}$, $i_{\frac{11}{2}}$, or $j_{\frac{15}{2}}$ orbitals. The experimental energy levels, $g$ factors, and $B\left(M2\mathrm{}\right)\mathrm{}$ value are compared with shell model calculations.

NUCLEAR REACTIONS ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^7{}_{}{}^{}\mathrm{Li}$,$3n$)${}_{}{}^{212}{}_{}{}^{}\mathrm{At}$ $E=32-44\mathrm{}$ MeV; measured $\gamma$ excitations, $\gamma -\gamma$ coin, $\gamma -W\left(\theta \right)$, pulsed-beam-$\gamma$ timing, perturbed angular distributions; deduced levels, $\gamma$ multipolarities, $J^{\pi }$, $T_{\frac{1}{2}}$, $B\left(E1\mathrm{}\right)\mathrm{}$, $B\left(M2\mathrm{}\right)\mathrm{}$, $g$.