Simultaneous deorientation and lifetime measurement in98Ru using the recoil distance Doppler shift method in inverse Coulomb excitation

Abstract

We measured the lifetimes of the ${2}_{1,2}^{+}$ and ${4}_{1}^{+}$ states in ${}^{98}$Ru in order to reduce their uncertainties and resolve the discrepancies in the literature for the lifetime of the ${4}_{1}^{+}$ state. Coulomb excitation in inverse kinematics was used to populate excited states in ${}^{98}$Ru, and the recoil distance doppler shift (RDDS) method was employed using the nNew Yale plunger device (NYPD). This technique combined with inverse Coulomb excitation requires several corrections due to relativistic and deorientation effects but yields high precision lifetimes. The determined ${B}_{4/2}=B({4}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})/B({2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})=1.86(16)$ agrees well with the vibrational limit. In order to analyze the data, a new method for the deorientation correction of RDDS data was developed using the perturbation of experimental angular correlations. The simultaneous measurement of deorientation and lifetime of a given state and its application are discussed. The method is suitable for radioactive beam experiments.