Spectroscopy of low-lying states in odd-odd146Eu

Abstract

Electron capture (EC) decay of ${}^{146}$Gd (${t}_{\frac{1}{2}}=48$ d) to the low lying states of ${}^{146}$Eu has been studied using high-resolution $\ensuremath{\gamma}$-ray spectroscopy. The ${}^{146}$Gd activity was produced by ($\ensuremath{\alpha},2n$) reaction at ${E}_{\ensuremath{\alpha}}=32$ MeV using a 93.8$%$ enriched ${}^{144}$Sm target. The level structure has been considerably modified from the measurement of $\ensuremath{\gamma}$-ray singles, $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidences and decay half lives. Lifetime measurement has been performed for the 3${}^{\ensuremath{-}}$ (114.06 keV) and 2${}^{\ensuremath{-}}$ (229.4 keV) levels of ${}^{146}$Eu using the mirror symmetric centroid difference (MSCD) method with LaBr${}_{3}$ (Ce) detectors. The lifetimes for these two states have been found to be 5.38 $\ifmmode\pm\else\textpm\fi{}$ 2.36 ps and 8.38 $\ifmmode\pm\else\textpm\fi{}$ 2.19 ps respectively. Shell model calculation has been performed using oxbash code in order to interpret the results.