Particle-Gamma Studies of Transitional Gd Nuclei Via Light-Ion Reactions

Gd nuclei with N $\sim$ 90 are of great interest due to a rapid change from vibrational to rotational character. Numerous experiments that have studied these nuclei were limited to either pure $\gamma$-ray or pure charged-particle studies. Recently, a series of experiments have been carried out at the 88-Inch cyclotron at LBNL, which combine relatively high-efficiency $\gamma$-ray and charged-particle spectroscopy in the same experiment. A beam of 25 MeV protons was incident on enriched $^{154}$Gd, $^{155}$Gd, $^{156}$Gd and $^{158}$Gd targets. Charged particles from the (p,p'), (p,d), and (p,t) reaction channels were detected using a Si-telescope array (STARS) and the coincident gamma-rays (in $^{152-158}$Gd) were detected using the Liberace HPGe clover array. The relatively high particle-gamma efficiency, precise energy resolution (via the $\gamma$ rays), and particle-$\gamma$ angular information provides a precision tool for spectroscopic studies. Preliminary results will be presented. This work was supported in part by the DOE under grant Nos. DE-FG02-05 ER41379 \& DE-FG52-06 NA26206 (UR), DE-AC52 07NA27344 (LLNL), DE-AC02 05CH11231 (LBNL).