Entry-level spin distributions and relative γ -neutron branching ratios of samarium isotopes populated by the (p,t) reaction

Abstract

The spin distribution populated in the $^{150}\mathrm{Sm}(p,t)$ reaction with 25 MeV protons has been investigated using the silicon telescope and high-purity germanium array Hyperion. Angular distributions of outgoing tritons and relative intensities of $\ensuremath{\gamma}$ rays from low-lying levels are used to deduce the initial spin distribution using statistical calculations and are compared with a semiclassical model of the $(p,t)$ reaction. Experimental and theoretical results suggest a peak strength near $4\ensuremath{\hbar}$ when gated on outgoing tritons detected in Hyperion, while the full $4\ensuremath{\pi}$ distribution may peak near $2\ensuremath{\hbar}$. Additionally, the average $\ensuremath{\gamma}$-neutron branching ratio is determined from the data with the aid of one of two new codes presented in this work. The analysis is extended to other recent studies of $^{152,154}\mathrm{Sm}(p,t)$ to form systematics of the spin-dependence of the surrogate method applied to heavy nuclei in the transitional to deformed region.