Odd Proton States in 165Tm, 167Tm, 169Tm, and 171Tm

Proton states in the odd mass isotopes 165 Tm, 167 Tm, 169 Tm, and 171 Tm have been studied using ( 3 He, d) and (α, t) reactions with 24 MeV 3 He and 27 MeV 4 He beams. The reaction products were analyzed with a magnetic spectrograph and detected with photographic emulsions, giving a resolution (FWHM) of 16–18 keV. The proton transfer l values were determined from ( 3 He, d) angular distributions and from the ratios of ( 3 He, d) and (α, t) cross sections. Nuclear structure factors, extracted using DWBA cross sections, were compared to those predicted by the Nilsson model with pairing corrections and Coriolis coupling included. Most of the previous assignments for low lying proton states have been confirmed, and several new ones were made. It is shown that the energy systematics of the intrinsic proton states cannot be attributed to variations in the quadrupole deformation, ε 2 , but can be explained by a small monotonic variation in the hexadecapole deformation, ε 4 .