A y-ray spectraswpic study of the high spin states of the nucleus ' 5' Dy has been performed using the reaction '0RPd(dsCa,4n)'"Dy at a bombarding energy of 205 MeV. Gamma rays were detected using the TESSA) multi-detector array. A set of discrete-line States forming a rotational band has been observed in the data and has been shown to extend up to a spin of around 6Ofi and an excitation energy of about 30MeV. The y-ray energy data is consistent with dynamic moment of inertia P of (85 f 3)h2 MeV-', indicating a large quadrupole deformation. A measurement of the collectivity of the band has been made using the Doppler Shift attenuation method, with the data for the lower spin states yielding a qlladrupole moment of e,,= (J813)e b. This is in excellent agreement with the calculated value of 17.6 e b for a superdeformed shape with a major-to-minor axis ratio of 2 : l . The data for the dynamic moment of inertia are consistent with the calculated high-j configuration for the superdeformed band, and the variation of 9' ' ' with frequency is reproduced by both cranked Nilssan and Woods-Saxon models. The intensity pattern for the band indicates that the superdeformed states are populated with an anomalously high intensity at spins close to the fission limit, suggesting that there is some enhanced population mechanism. The hand is observed to de-excite suddenly at around I = 26h, although the linking transitions between these States and the yrast States have not been Observed. Evidence is presented for the existence of non-yrast superdeformed bands in the p r a y continuum.The intensity of these bands is measured and compared with the results of Monte Carlo simulations. NUCLEAR REACnONS "Pd("Ca,4n) E ("Ca) = 205 MeV; measured E,, I,, y-y coincidence and angular correlations. '''Dy; deduced levels, decays; assigned E,, J and n. Superdeformed band; quadrupole moment. *licmscopic structure, comparison with Nilssan and Woods-Saxon models. Feeding mechanisms. Comparison with results of Monte Carlo simulations.

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High spin states of 175'176pt have been populated in 144Sm(35Cl, pxn) reactions at beam energies of 175-185 MeV. In-beam y-ray spectroscopic techniques using the ESSA30 spectrometer array were adopted. Levels up to spin 26 in 176pt and tentatively up to spin 45/2 in 175pt have been identified. The data are interpreted within the framework of Cranked Shell Model calculations using the deformed Woods-Saxon potential and including monopole pairing.