Electromagnetic properties of /sup 230/Th studied by Coulomb excitation

The Coulomb excitation of /sup 230/Th by 135 MeV /sup 32/S ions was studied using the particle-gamma coincidence technique. Scattered projectiles were detected within an angular range of 30/sup 0/< or =THETA< or =172/sup 0/, and the impact-parameter dependence of the gamma-ray intensities was measured. Excitation of the ground-state rotational band was observed up to the 10/sup +/ state, while the ..beta..- and ..gamma..-vibrational bands were seen up to the 4/sup +/ and 8/sup +/ states, respectively. Levels belonging to the K/sup ..pi../ = 0/sup -/ and 1/sup -/ octupole vibrational bands were also identified. From the scattering-angle dependent gamma-ray intensities E2 transition matrix elements within the ground band and interband matrix elements connecting levels of the ..gamma.. band with the ground band are deduced. Gamma-ray branching ratios for transitions from the ..gamma..- and octupole-vibrational bands to ground-band levels are also determined. Both transition matrix elements and branching ratios are compared with nuclear-model predictions.