Charge Radius Change in the Heavy Tin Isotopes until A = 132 from Laser Spectroscopy

Laser spectroscopy measurements have been carried out on the very neutron-rich tin isotopes with the COMPLIS experimental setup. Using the 5s25p23P0 → 5s25p6s3P1 optical transition, hyperfine spectra of 126-132Sn and 125m, 127m, 129m-131mSn where recorded for the first time. The variation of the mean-square charge radius ( δ〈r2〉) between these nuclei and nuclear moments of the isomers and the odd isotopes were thus measured. An odd-even staggering which inverts at A = 130 is clearly observed. This indicates a small appearance of a plateau on the δ〈r2〉 which has to be confirmed by measuring the isotope shift beyond A = 132.