High-spin results for ${}_{}{}^{155}{}_{}{}^{}\mathrm{Tb}$

High-spin states in ${}_{}{}^{155}{}_{}{}^{}\mathrm{Tb}$ have been identified via the weak p4n exit channel of the ${}_{}{}^{36}{}_{}{}^{}\mathrm{S}$ + ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$ reaction using the Gammasphere array. The π${\mathit{h}}_{11/2}$ yrast band has been established up to ${\mathit{I}}^{\mathrm{\pi }}$ = 67/$2^{\mathrm{-}}$ filling an important gap in the N = 90 high-spin systematics. The variation of the first ${\mathit{i}}_{13/2}$ neutron backbend as a function of proton number for N = 90 isotones and trends regarding the phenomenon of signature splitting and signature inversion in the odd-Z nuclei are discussed. © 1996 The American Physical Society.