Charge radii of neutron-deficient ^36,37,38Ca

The mean-square charge radii, <r²>, of neutron-deficient ^36,37,38Ca below the neutron number N = 20 were determined at the BEam COoler and LAser spectroscopy (BECOLA) facility at NSCL/MSU, using the collinear laser spectroscopy technique. The obtained <r²> are in the vicinity of the proton dripline and impose new challenges on state-of-the-art models, as the coupling of pairing correlations to the continuum becomes critical. The overall behavior of the chain of Ca <r²> across N = 20 and 28 will be discussed, together with the newly determined electromagnetic moments of ³⁷Ca.