The Study Of The Odd-Proton Nucleus Ta-169 At High-Spin

The level structure of 169Ta has been studied using the reactions (Gd(F,5n))-Gd-155-F-19, E = 85.5-100 MeV and (Sn(V,4n))-Sn-122-V-51, E = 223 MeV. Four rotational bands of 169Ta have been identified with assignments 1/2-[541], 9/2-[514], 5/2+[402], 1/2+[41 1 ] and a decoupled band was identified but not assigned to any configuration. Different configurations are observed to have different band-crossing frequencies and these differences are consistent with configuration-dependent deformation driving effects. The crossing frequency of the band based on the 1/2-[541] configuration is deduced to be 0.305 MeV/HBAR which is delayed by about 55 keV in comparison with the yeast bands of its even neighbours. The first band crossings of 169Ta are attributed to the alignment of a pair Of i13/2 quasineutrons, while the second band crossings may correspond to h11/2 two-quasiproton alignment. The deformation driving effects of quasiparticle orbitals, B(Ml)/B(E2) values of the 9/2-[514] and 5/2+[402] bands and the band crossings in 169Ta are discussed. [GRAPHICS]