$γ$-ray Angular Distributions in Single Nucleon Transfer Reactions with Exotic Strontium Isotopes

Abstract

$γ$-ray angular distributions help assign spin and parity to excited energy levels in nuclei. The spectroscopy of $^{94,96}$Sr studied through the single neutron transfer reactions with $^{95}$Sr beam in inverse kinematics [$^{95}$Sr(d,p)$^{96}$Sr; $^{95}$Sr(d,t)$^{94}$Sr] revealed a rich nuclear structure with many excited states. While the spin-parities were assigned to low lying states through techniques like particle angular distributions and angular momentum transfer, those for higher lying states were ambiguous. The goal of this project is to develop the Gamma-ray angular distributions and correlations techniques to assign spin-parity to these states. In this work, the $γ$-ray angular distributions for 815 keV transition from the first excited state to ground state $(2^{+} \rightarrow 0^{+})$ in $^{96}$Sr are measured. The alignment of this state is calculated from these measurements and compared to the theoretically calculated alignment for this state which is determined by coupling the spins of reactants and the orbital angular momentum transfered. The values agree within experimental limits justifying the technique. It is then applied to some other transitions and important results are discussed. Angular correlations cannot be performed with this data since statistics turn out to be limiting factor at the crystal level.