Utilizing angular distributions to measure the spin imparted to the continuum region of Gd nuclei by light-ion transfer reactions

Historically it has proven extremely difficult to probe the properties of low-spin highly-excited states far above the yrast line in the bound quasi-continuum. We present the first measurement of the initial spin distribution of this region, following (p,d) and (p,t) reactions on $^{154}$Gd and $^{158}$Gd targets. The 25 MeV proton beam was provided by the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. A silicon telescope array, STARS, was used to detect light ions. We find that the spin transferred increases with excitation energy. Between 3 and 8 MeV, assuming a single dominant angular momentum transfer component, the measured angular distribution for the (p,d) reactions are well reproduced by DWBA calculations for $\Delta$L=4$\hbar$ transfer, whilst the (p,t) reactions are better characterized by $\Delta$L=5$\hbar$. A weighted combination of DWBA calculations, agrees excellently with experimental angular distributions.