On the production and chemical separation of Hs (element 108)

Chemical separation of Hs provides an excellent tool to study the formation reactions and nuclear structure of nuclei close to the deformed nuclear shells at Z=108 and N=162 due to a high overall efficiency and a very high purification factor. Here we report on results of a recent Hs chemistry experiments performed at GSI Darmstadt. Hs atoms were produced in the nuclear reaction 248Cm(26Mg, xn)274-xHs. Simultaneously, short-lived Os isotopes were produced for a comparative study. Recoil products were thermalized in He/O2 (10% of O2) gas mixture and volatile Hs and Os tetroxides were formed and transported with the gas flow within a few seconds to the detection system COMPACT (Cryo On-line Multidetector for Physics And Chemistry of Transactinides). Volatile species were adsorbed in the thermochromatographic channel consisting of 2 x 32 PIPS detectors and kept at temperatures from +20 degree C to -140 degree C. The comparative study of the volatility of Hs and Os tetroxides confirmed the previously observed lower volatility of HsO4. From the detected decay chains new data on the nuclear structure of nuclei close to Z=108 and N=162 were deduced.