New beta-delayed proton precursors in the rare-earth region near the proton drip line - art. no. 061302

The beta-delayed proton precursors Nd-125, Pm-128, Sm-129,Gd-137, and Dy-13 9 near the proton drip line were produced by the irradiation of Mo-92, Ru-9 6, and Cd-106 with an Ar-36 beam, and definitely identified for the first t ime using proton-gamma coincidence in combination with a He-jet tape transp ort system. Their half-lives were determined to be 0.60(15) s, 1.0(3) s, 0. 55(10) a, 2.2(2) a, and 0.6(2) a, respectively. The measured energy spectra of beta-delayed protons and estimated proton branching ratios to the final states in "daughter" nuclei were fitted by a statistical model calculation , and then the spins and parities of Nd-125, Sm-129, Gd-137, and Dy-139 wer e preliminarily assigned as 5/2(+/-), 1/2(+)(or 3/2(+)), 7/2(+/-), and 7/2( +), respectively. The agreement between the spin-parity assignments and the predicted Nilsson diagrams indirectly indicates that the ground states of Nd-125, Sm-129, Gd-137, and Dy-139 are highly deformed with beta(2) similar to 0.3. [S0556-2813(99)50112-X].