Ga71andGa73levels as observed in the (t,p) reaction

A study of the ($t$,$p$) reaction on the two stable Ga isotopes has been performed. The reaction protons were analyzed in a quadrupole-dipole-dipole-dipole spectrometer with a resulting energy resolution approximately 18 keV. Levels up to about 3 MeV excitation energy in ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ga}$ and 2.75 MeV in ${}_{}{}^{73}{}_{}{}^{}\mathrm{Ga}$ were measured with 11 new levels observed in the first case and 18 in the second. The angular distributions have been compared to pure distributions observed in the ${}_{}{}^{72,74}{}_{}{}^{}\mathrm{Ge}$($t$,$p$) reactions at the same energy and found to correspond mostly to pure angular momentum ($L$) transfer although mixing of $L$'s is allowed. A number of new spins assignments are made for Ga levels and the results are used to discuss the spin of ${}_{}{}^{73}{}_{}{}^{}\mathrm{Zn}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$. The striking splitting of the $L=0\mathrm{}$ strength in three approximately equal components, observed in ${}_{}{}^{73}{}_{}{}^{}\mathrm{Ga}$, strongly supports a transition in nuclear deformation between $N=40\mathrm{} \mathrm{and} 42$.