Toward charge radii measurements of neutron-deficient Ca

The charge radii, $\langle r^{2} \rangle$, of $_{20}$Ca isotopes serve as an important reference for the size and shape of neighboring nuclides, since this element has two naturally-occurring isotopes at the $N=20$ and 28 neutron shell closures. An experiment has been approved to measure $\langle r^{2} \rangle$ of Ca for neutron-deficient isotopes across $N = 20$. The $\langle r^{2} \rangle$ of $_{18}$Ar and $_{19}$K isotopes show a disappearance of the shell-closure signature at $N = 20$. The aim of this measurement is to gain a microscopic understanding of this abnormal behavior. Current developments at the BEam COoling and LAser spectroscopy (BECOLA) facility at NSCL/MSU in preparation for this measurement include offline production and spectroscopy of stable Ca$^{+}$ and simulations of a new photon detection system.