NEUTRON I-13 2 INTRUDER BAND IN SM-139

The high-spin structure of Sm-139 has been investigated with the (Pd(S ,5n))-Pd-110-S-34 reaction at a beam energy of 159 MeV at the Stony Br ook Tandem/Superconducting LINAC facility. The TESSA3 spectrometer arr ay was used to collect gamma-gamma coincidence data from which an exte nded decoupled band structure has been found. It is proposed that this band is based on the i13/2 (OMEGA = 1/2) neutron intruder orbital. Th e decay pattern, enhanced dynamic moments of inertia, and aligned spin s are consistent with the nui13/2 bands in neighboring odd-neutron nuc lides. Total Routhian surface and cranked shell model calculations rep roduce qualitative features of these nuclides, further supporting the proposed interpretation.