OLGA II, an on-line gas chemistry apparatus for applications in heavy element research

Summary. The chemistry of superheavy elements -or transactinides from their position in the Periodic Table -is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators ("pre-separator") are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table.

Section: Techniques and Instruments For Gas-phase Chemistrymentioning

confidence: 99%

“…Isothermal gas-adsorption chromatography experiments at the GSI [108,211] used the OLGA [147] and Cl 2 , saturated with SOCl 2 , and traces of O 2 as reactive gases to study the formation and volatility of the presumably formed dioxide dichlorides. Break-through curves, measured for Mo, W, and Sg compounds between about 150 and 300…”

Section: Gas-phase Chemistrymentioning

confidence: 99%

Chemistry of superheavy elements

Schädel

2012

“…Recently, element 112 was investigated in a gas phase chemistry experiment in its elemental state [3]. Single atoms of these elements were either transported to a chemistry setup with a gas-jet, i.e., attached to aerosol particles that are suspended in rapidly flowing carrier gas [4][5][6][7][8] or as volatile species after thermalization in a gas mixture containing the reactive component [9,10]. Element 112 was transported in its volatile elemental state [3].…”

Section: Gas Phase Chemistry With Transactinidesmentioning

confidence: 99%

Gas chemical investigation of hafnium and zirconium complexes with hexafluoroacetylacetone using preseparated short-lived radioisotopes

Düllmann

Gregorich²,

Pang

et al. 2009

Zirconium / Hafnium / Hexafluoroacetylacetonates / Thermochromatography / Isothermal gas chromatogaphy / Physical preseparation Summary. Volatile metal complexes of the group 4 elements Zr and Hf with hexafluoroacetylacetonate (hfa) have been studied using short-lived radioisotopes of the metals. The new technique of physical preseparation has been employed where reaction products from heavy-ion induced fusion reactions are isolated in a physical recoil separator -the Berkeley Gas-filled Separator in our work -and made available for chemistry experiments. Formation and decomposition of M(hfa) 4 (M = Zr, Hf) has been observed and the interaction strength with a fluorinated ethylene propylene (FEP) Teflon surface has been studied. From the results of isothermal chromatography experiments, an adsorption enthalpy of −ΔH a = (57 ± 3) kJ/mol was deduced. In optimization experiments, the time for formation of the complex and its transport to a counting setup installed outside of the irradiation cave was minimized and values of roughly one minute have been reached. The half-life of 165 Hf , for which conflicting values appear in the literature, was measured to be (73.9 ± 0.8) s. Provided that samples suitable for α-spectroscopy can be prepared, the investigation of rutherfordium (Rf), the transactinide member of group 4, appears possible. In the future, based on the studies presented here, it appears possible to investigate short-lived single atoms produced with low rates (e.g., transactinide isotopes) in completely new chemical systems, e.g., as metal complexes with organic ligands as used here or as organometallic compounds.

“…applying the on-line gas chemistry apparatus OLGA [1][2][3][4] was used to investigate the gas phase chemistry of superheavy elements (SHE) E104 (Rf), E105 (Db), E106 (Sg), and E107 (Bh). For the investigation of volatile species of Hs the cryo-thermochromatography method was developed [5].…”

Section: Introductionmentioning

confidence: 99%

Prediction of the thermal release of transactinide elements (112 ≤Z≤ 116) from metals

Wittwer¹,

Dressler

Eichler³

et al. 2013

Summary. Metallic catcher foils have been investigated on their thermal release capabilities for future superheavy element studies. These catcher materials shall serve as connection between production and chemical investigation of superheavy elements (SHE) at vacuum conditions. The diffusion constants and activation energies of diffusion have been extrapolated for various catcher materials using an atomic volume based model. Release rates can now be estimated for predefined experimental conditions using the determined diffusion values. The potential release behavior of the volatile SHE Cn (E112), E113, Fl (E114), E115, and Lv (E116) from polycrystalline, metallic foils of Ni, Y, Zr, Nb, Mo, Hf, Ta, and W is predicted. Example calculations showed that Zr is the best suited material in terms of on-line release efficiency and long-term operation stability. If higher temperatures up to 2773 K are applicable, tungsten is suggested to be the material of choice for such experiments.