Decay of neutron-rich Ar 45 and Ar 46

The decay of $^{45}\mathrm{Ar}$ and the previously unreported decay of $^{46}\mathrm{Ar}$ have been studied from sources prepared in the $^{48}\mathrm{Ca}(n,2p,2n)^{45}\mathrm{Ar}$ and $^{48}\mathrm{Ca}(n,2\mathrm{pn})^{46}\mathrm{Ar}$ reactions. The half-lives of $^{45}\mathrm{Ar}$ and $^{46}\mathrm{Ar}$ were measured to be 20.8 and 8.9 sec, respectively. On the basis of results from $\ensuremath{\gamma}$ spectroscopy levels in $^{45}\mathrm{K}$ and $^{46}\mathrm{K}$ are determined. Of 14 $\ensuremath{\gamma}$ rays observed in the decay of $^{45}\mathrm{Ar}$, 13 are placed in a $^{45}\mathrm{K}$ level scheme. The only $\ensuremath{\gamma}$ ray observed in $^{46}\mathrm{Ar}$ decay is one from a ${1}^{+}$ core state in $^{46}\mathrm{K}$ at 1944 keV. The systematics of K nuclei are discussed.