Core-excitations in 209Po

The properties of high spin states in Po have been investigated using the Hg (Be,4n) Po reaction at a bombarding energy of 62 MeV. Decay properties for states in Po up to an excitation energy of 8392 keV and spins up to J = (47/2) have been deduced. The mean life of the level at 4266 keV was determined as 172(5) ns and a limit of < 15 ns was determined for that at 5504 keV. The level scheme is compared with predictions of multi-particle shell model calculations. The lowest core excited state is confirmed to be the 31/2- state at 4266 keV. Another core excited state lies at 5356 keV, while above 5.5 MeV the yrast line is exclusively composed of such excitations