Low lying spectroscopy of odd-odd ${}^{146}$Eu

Abstract

Electron Capture (EC) decay of ${}^{146}$Gd($t_{1/2}$ = 48d) to the low lying states of ${}^{146}$Eu has been studied using high-resolution ${\hat{I}}^3$ ray spectroscopy. The ${}^{146}$Gd activity was produced by ($\hat{I}\pm$, 2n) reaction at E${}_{\hat{I}}\pm$ = 32 MeV using 93.8% enriched ${}^{144}$Sm target. The level structure has been considerably modified from the measurement of ${\hat{I}}^3$ ray singles, ${\hat{I}}^3{\hat{I}}^3$ coincidences and decay half lives. Lifetime measurement has been performed for the 3${}^{-}$ (114.06 keV) and 2${}^{-}$ (229.4 keV) levels of ${}^{146}$Eu using Mirror Symmetric Centroid Difference (MSCD) method with LaBr${}_3$ (Ce) detectors. The lifetimes for these two states have been found to be 5.38 $\pm$ 2.36 ps and 8.38 $\pm$ 2.19 ps respectively. Shell model calculation has been performed using OXBASH code in order to interpret the results.

9 pages, 11 figures