Structure of Cl38 and the quest for a comprehensive shell model interaction

The higher-spin structure of Cl-38 (N = 21) was investigated following the Mg-26(C-14, pn) reaction at 30 and 37 MeV beam energies. The outgoing protons were detected in an E-Delta E Si telescope placed at 0 degrees close to the target with a Ta beam stopper between the target and telescope. Multiple gamma rays were detected in time coincidence with the protons using an enhanced version of the FSU gamma-detection array. The level scheme was extended up to 8420 keV with a likely spin of 10 h. A new multishell interaction was developed guided by the experimental information. This FSU interaction was built by fitting to the energies of 270 experimental states from C-13 to Ti-51. Calculations using the FSU interaction reproduce observed properties of Cl-38 rather well, including the spectroscopic factors. The interaction has been successfully used to interpret the 1p1h and 2p2h configurations in some nearby nuclei as well.