Determination of effective charges in the lower $pf$ shell

Recently, the use of the standard effective charges, $e_p=1.5$ and $e_n=0.5$, has been called into question, and the noncanonical values of $e_p=1.15$ and $e_n=0.8$ have been suggested for the upper $fp$ shell\footnote{R.~du~Rietz \textit{et~al.}, Phys. Rev. Lett. \textbf{93}, 222501 (2004)}. $^{50}$Ca is ideally situated for determining the $e_n$ effective charge due to its closed $\pi(sd)$ shell. The results of the measurement of the \mbox{B(E2; 0$_{1}^{+}\rightarrow2_{1}^{+}$)} transition rate in $^{50}$Ca, which is proportional to $e_n^2$, via intermediate-energy Coulomb excitation at the National Superconducting Cyclotron Laboratory will be reported. In this experiment, $\gamma$ rays were observed using the high-efficiency NaI APEX Array in conjunction with particle identification by the S800 Spectrograph.