Recoil ions from the β decay of Sb134 confined in a Paul trap

Abstract

The low-energy recoiling ions from the $\ensuremath{\beta}$ decay of $^{134}\mathrm{Sb}$ were studied by using the Beta-decay Paul Trap. Using this apparatus, singly charged ions were suspended in vacuum at the center of a detector array used to detect emitted $\ensuremath{\beta}$ particles, $\ensuremath{\gamma}$ rays, and recoil ions in coincidence. The recoil ions emerge from the trap with negligible scattering, allowing $\ensuremath{\beta}$-decay properties and the charge-state distribution of the daughter ions to be determined from the $\ensuremath{\beta}$-ion coincidences. First-forbidden $\ensuremath{\beta}$-decay theory predicts a $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\nu}$ correlation coefficient of nearly unity for the ${0}^{\ensuremath{-}}$ to ${0}^{+}$ transition from the ground state of $^{134}\mathrm{Sb}$ to the ground state of $^{134}\mathrm{Te}$. Although this transition was expected to have a nearly 100% branching ratio, an additional 17.2(52)% of the $\ensuremath{\beta}$-decay strength must populate high-lying excited states to obtain an angular correlation consistent with unity. The extracted charge-state distribution of the recoiling ions was compared with existing $\ensuremath{\beta}$-decay results and the average charge state was found to be consistent with the results from lighter nuclei.