Advances toward and beyond the proton drip line with recoil-isomer tagging

This paper reviews the past, present and future status of recoil-isomer tagging at the University of Jyvaskyla. The main focus of this research has been to access isomeric states at and beyond the mass,140 proton drip line. Recoil-isomer tagging was first used at the University of Jyvaskyla in 1998 to establish the prompt rotational band built upon a K-pi = 8(-) isomeric state in Gd-138. Since that time a series of experiments have been performed which have studied isomeric states in the N = 77 isotones (63EU77)-E-140, Tb-142(63)77 and Ho-144(67)77, and in the N = 74 K-isomer chain, Gd-138(64)74 and (66DY74)-D-140. These experiments have revealed valuable first information about deformations, single-particle excitation energies and hindrance factors in nuclei at and beyond the proton drip line where little or no information previously existed. The results of the most-recent experiments were discussed. These experiments established new isomeric states in (66DY77)-D-143, (61PM75)-P-136, and Gd-137(64)73 and a further two isomers which are currently unplaced. The paper concludes with a discussion of the future prospects for this research including the increased efficiency of the recoil-isomer tagging technique with a new Multi-Wire Proportional Counter (MWPC) detector which was designed and built at the University of Manchester. The first results from this new setup were shown.