Observation of signature inversion in odd-odd Ir-178

High spin states in Ir-178 have been studied via the Sm-152(P-31,5n gamma)Ir-178 reaction through excitation functions, X-gamma and gamma-gamma -t coincidence measurements. According to the band structure characteristics and the measured intraband B(M1)/B(E2) ratios, two rotational bands are identified and assigned to be associated with the pih(9/2)x nui(13/2) and pih(11/2)x nui(13/2) configurations, respectively. Both bands show the signature inversion feature.