Principal challenges in the study of transactinide elements (Z ≥ 104) are production rates as low as single-atoms per week and shortening half-lives as Z increases. The frontier of transactinide research uses on-line gas adsorption chromatography (GC), such as the Cryo-OnLine Detector (COLD) as the primary method of element identification and chemical investigation. These state-of-the-art GC experiments provide the necessary detection sensitivity for single atoms, while allowing experiments to be performed on radioisotopes with half-lives of ≈ 500 ms. The Superheavy elements Cn (Z = 112) and Fl (Z = 114) can thus be studied. During our experiments, Hg is produced simultaneously in nuclear fusion evaporation reactions for homolog studies of Cn, while acting as a tracer to monitor experimental conditions. At is a by-product of multinucleon-transfer reactions but similarly provides useful data. Recent upgrades in the equipment with the inclusion of mass spectrometry for the gas composition analysis have shown that there is a strong correlation between the composition of unwanted residual trace gases and transport yields of different elements (Fig. 1).<br/>We present the observed influences of impurities in the carrier gas on the chromatographic yield and the importance of accurately knowing potential contaminants in similar experiments. These observations are of high significance as they highlight the importance of tightly controlling the purity of gases used in experiments at the single-atom scale. This knowledge can therefore be used to prevent unwanted side-reactions, or to increase transport yields in the future and has initiated the development of a new experimental setup ‘Trace-gas Reaction Analysis for Chromatography (TRACY)’ designed specifically for this purpose.

Superheavy element chemistry and the residual gas effects on the chromatographic yield of homologs Hg and At

ACS Spring Meeting 2021

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