Decay studies of neutron-deficient nuclei near the Z=64 subshell: Dy141, Tb141, Gdg+m141, and Eum141

The and delayed proton decays of mass separated A=141 isotopes with Z=6366 were investigated with an on-line mass separator. Branching ratios have been redetermined for the total decay of the 2.7(3) s, (11/2- isomer Eum141 at 96.5 keV (13-2+4%), and for the direct feeding of the 1.58 keV (3/2+ level of Sm141 in the decay of 40-s Eug141 [73(5)%]. Detailed decay schemes have been constructed for the decays of the (11/2- isomer Gdm141 [11(2) isomeric transition] and the (1/2+ ground state, Gdg141. Half-lives of 24.5(5) s and 14(4) s, respectively, have been determined for these isomers. A delayed proton branch of 0.03(1)% was identified in the decay of Gdg141. A detailed decay scheme was also constructed for 3.5(2)-s Tb141 and a J=(5/2- was assigned to its ground state, at variance with the systematics of heavier, odd-mass Tb isotopes. All -ray assignments to the various isotopes are based on x and coincidences and on half-life measurements. A 0.9(2)-s half-life for Dy141 was determined from its delayed proton decay. All spin assignments proposed in this paper are discussed in terms of Nilsson level diagrams and nuclear shapes.