γ-ray linear polarization measurements following heavy-ion bombardment of2s−1dshell nuclei

As part of a program utilizing the fusion-evaporation reaction to study high-spin states in $A\simeq 40$ nuclei, linear polarization measurements were made on the $\gamma$ rays emitted following fusion of the six projectile-target combinations: ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ + ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ + ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, and ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ + ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$. All beam energies were 40 MeV except the last, which was 45 MeV. The linear polarization of about 50 $\gamma$ rays from the highly aligned states were measured in each experiment using a two-crystal Ge(Li) Compton polarimeter. The results are tabulated. As an example of the application of these results, the polarization data in conjunction with previous $\gamma -\gamma$ coincidence and $\gamma$-ray angular distribution measurements suggest $E2\mathrm{}$ character for the $\gamma$ cascades between the ${}_{}{}^{41}{}_{}{}^{}\mathrm{K}$ levels at 4983, 4275, 2762, and 1294 keV and thus support the spin-parity sequence $\frac{19}{2^{-}}$, $\frac{15}{2^{-}}$, $\frac{11}{2^{-}}$, and $\frac{7}{2^{-}}$ for these states. Applications to the spectroscopy of other levels in ${}_{}{}^{41}{}_{}{}^{}\mathrm{K}$,