Continuum studies in Gd nuclei by particle-$\gamma $ coincidences

An experiment was carried out at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory to study Gd isotopes in the vicinity of the N=90 transitional region. A 25 MeV proton beam was incident on $^{158/155/154}$Gd targets and used to populate states in $^{152-158}$Gd by (p,p'), (p,d) and (p,t) reactions. The exit channel is selected by gating on charged particles using the STARS Si-Telescope array, which also gives the excitation energy of the residual nucleus. Coincident $\gamma $ information is obtained using the LIBERACE Clover array. Particle-$\gamma $ coincidences provide a powerful tool for probing the residual nucleus [1]. For example, particles in coincidence with a specific $\gamma $ ray produce a spectrum representing all levels populated in the nucleus that subsequently decay into the state from which the $\gamma $ ray originates. Results will be presented that give an insight into the population distribution of the high level density region above the pair gap in the even-even Gd nuclei via light ion reactions. [1] J. M. Allmond et al. Phys.Rev.C 81, 064316 (2010) Work supported in part via DOE grant numbers DE-FG02-05 ER41379 {\&} DE-FG52-06 NA26206(University of Richmond), DE-AC52 07NA27344(LLNL) and DE-AC02 05CH11231(LBNL).