High-spin level structure of 209Rn

The excited states of 209Rn (Z = 86, N = 123) have been populated by the heavy -ion induced fusion evaporation reaction 198Pt (16O, 5n) 209Rn at a beam energy of 102 MeV. The de -excited gamma rays were detected with the Compton suppressed clover HPGe detectors of the Indian National Gamma Array (INGA) set-up. The high spin spectroscopic study of 209Rn has been carried out up to an excitation energy of 7.9 MeV and spin (55/2) h over bar . Spin -parity assignments of the excited levels have been determined and are confirmed on the basis of the ratio of directional correlation and polarization asymmetry measurement. The possible presence of new isomeric states has been observed and the half-lives have been estimated. A negative parity sequence of M1 transitions has been observed which exhibits the property of magnetic rotation and is interpreted in the framework of semiclassical model calculation. The large basis shell -model calculation has been performed for all the nuclear levels and is found to be in well agreement with the experimental results.