Cryo thermochromatography

From this experiment it appears that the interaction of element 112 with an Au or Pd surface is much weaker than for Hg. The obtained enthalpies of adsorption were -A//a°(Hg) > 75 kJ/mol and -A//a°(element 112) < 55 kJ/mol. Such a vastly different chemical behavior as in the present case of element 112 compared to its lighter homologue Hg has not been observed for any of the lighter transactinides so far and might reflect the predicted inertness and enhanced volatility due to relativistic effects. Obviously, in a next step, the enthalpy of adsorption of element 112 on Au surfaces has to be measured experimentally. This can be done with a cryo thermochromatography detector containing Au coated detectors. The temperature in the gradient should start at room temperature and reach down to the adsorption temperature of Rn, which should be still above the temperature of liquid N2. 

In an experimental campaign, the reaction Mg + " Cm was investigated at five different beam energies [88, 89]. For these experiments, performed at GSI, a heated recoil chamber, which was operated at 400 °C, was constructed in order to optimize the rapid formation of tetroxides. Also, the new cryo thermochromatography detector cryo on-line multidetector for physics and chemistry of transactinides (COMPACT), with an improved detection efficiency, was developed. Version 1 had a detection efficiency for a single a particle of 78% and version 2 of 93%. This way, the probabihty to detect all members of a decay chain was significantly improved. In two experiments, a total of 26 decay chains assigned to Hs isotopes were identified. 

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