A g-factor measurement of the $4^+$ state in $^{76}$Ge

The $^{70-76}$Ge isotopes are transitional nuclei with $E_4^+/E_2^+$ ratios varying from 2.07 to 2.51. The systematic studies of g factors of $2^+_1$ and $4^+_1$ excited states provide an understanding of the microscopic structure of these nuclei since the g factors are very sensitive to the proton and neutron contributions to the wave functions. The measured results can be compared to the predictions of either shell model calculations or collective vibrational excitations. The measured g factors of $2^+_1$ in Ge nuclei, as well as in neighboring Zr and Se nuclei show reasonable agreement with $Z/A$, a signature of collective behavior. However, in this region the g factors of the $4^+_1$ states are somewhat larger than $Z/A$, albeit with large error bars. In this work, the first measurement of the g factor of the excited $4^+_1$ state of $^{76}$Ge using the Transient Field (TF) technique will be presented. The $4^+_1$ state of $^{76}$Ge was populated by Coulomb excitation on a C target of a beam of $^{76}$Ge (190-230 MeV) in inverse kinematics. Work supported by the U.S. National Science Foundation and U.S.D.O.E under grant DE-FG02-91ER-40609.