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A: Atomphysik

A 5: Neue Aspekte der Atomphysik I

A 5.6: Vortrag

Montag, 22. März 2004, 17:45–18:00, HS 132

Gas phase chemical investigation of new elements produced in Ca-48 induced nuclear fusion reactions: status and perspectives — •Robert Eichler — Labor fuer Radio-und Umweltchemie Paul Scherrer Institut, CH-5232 Villigen, PSI

Recently, at FLNR Dubna, Russia numerous new isotopes of transactinide elements have been discovered in Ca-48 induced nuclear reactions with actinide targets. Their unambiguous identification is complicated, since all measured correlated decay chains end up in an unknown region of nuclei. We present results from gas phase chemical experiments to characterize element 112. The isotope with the mass number 283 is produced in the reaction of Ca-48 and U-238 and decays with a half-live of about 5 min by spontaneous fission (SF). The volatile reaction products are investigated using the IVO (In-situ Volatilisation and On-line Detection) technique, aiming to measure adsorption properties of element 112 with a gold surface. Simultaneously, the elements mercury and radon have been investigated. This procedure allows for a distinction of the behaviour of element 112 between noble gas and metal. The predictions regarding its chemical beahavior are complicated, because of the expected strong relativistic effects in the electron structure of the element, caused by the high nuclear charge. We observed SF decay events, which we tentatively attribute to 112-283. A thermochemical analysis of the chromatographic results allowed for estimation of first thermodynamic data for element 112. Status of the data analysis and prospects for future experiments will be presented.