Decay of149Gd and directional correlations of gamma cascades in149Eu

Abstract

Abstract. The decay of 149Gd(9.4 d) to the levels of 149En has been studied using large volume high resolution Ge(Li) and NaI(T1) detectors. 7-7 coincidence and directional correlation experiments have been performed. New 7-rays at energies 131.9, 278.6, 384.7, 415.7, 599.2, 726.5, 734.7, 956.4 and 1,231.1 keV in t49Eu have been observed. Three new levels in 149Eu have been placed at 956.4, 1,082.0 and 1,231.1 keV. Spin-parity assignments have been made to some of the levels in 149Eu. Multipolarity assignments have been made for most of the electromagnetic transitions from the conversion coefficients obtained through the knowledge of our 7-transition intensities and the published conversionelectron intensities. Based on the new y-transitions observed in the singles and coincidence spectra, a revised level scheme has been proposed for 149Eu and compared with previously published level schemes. Radioactivity 149Gd; measured T~/2, E~, Iv, Y7 coin, yT(0), I.C.C., 149Eu deduced levels, J, y-mixing, re. Enriched targets, Ge(Li) detectors.