THE N=83 NUCLEUS DY-149 FROM GAMOW-TELLER DECAY OF ITS 11 2- AND 1/2+HO-149 PARENTS/

A high-sensitivity gamma-spectroscopic study of the 149Ho pih11/2 and pis1/2 beta-decays using mass separated sources has located dominant O + --> 1+ GT decay strength associated with decay of paired h11/2 proto ns, leading to 3 qp-states in the 149Dy daughter nucleus. In their gam ma-decay low-lying 149Dy levels characteristic of an N = 83 nucleus ar e excited. They include the vf7/2, vP3/2, vh9/2 and vp1/2 single parti cle- and the vs1/2(-1) and vd3/2(-1) two-particle one-hole states, as well as the vf7/2 x 3- and vf7/2 x 2+ particle-phonon multiplets. A sy nopsis is given of these excitations in the N = 83 isotones from Nd-14 3 to 153Yb. The 149Dy GT decay strength is discussed in terms of the T b-147(82) and Dy-148(82) decays. The strength function results are als o compared with independent 149Ho 11/2- decay data from the literature based on total gamma-ray absorption measurements.