Enrichment of the Superheavy Element Rg in Natural Au

TL;DR

This study demonstrates the enrichment of the superheavy element Rg in natural gold through high-temperature vacuum heating, supporting the existence of long-lived isomeric states in 261Rg.

Contribution

It presents a novel method to enrich Rg in gold and provides evidence for long-lived super- or hyperdeformed isomeric states in 261Rg.

Findings

Rg enrichment was achieved by heating Au in vacuum at high temperature.

The abundance of Rg was enriched by three to four orders of magnitude.

Long-lived isomeric states in 261Rg are supported by experimental evidence.

Abstract

Based on the observation of the long-lived isotopes 261Rg and 265Rg (Z = 111, t(1/2) >= 10^(8) y) in natural Au, an experiment was performed to enrich Rg in 99.999% Au. 16 mg of Au were heated in vacuum for two weeks at a temperature of 1127 deg. C (63 deg. C above the melting point of Au). The content of 197Au and 261Rg in the residue was studied with high resolution inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). The residue of Au was 3x10^(-6) of its original quantity. The recovery of Rg was a few percent. The abundance of Rg compared to Au in the enriched solution was about 2x10^(-6), which is a three to four orders of magnitude enrichment. It is concluded that the evaporation rate of Rg from an Au matrix in vacuum at 63 deg. C above the Au melting point is lower than that of Au. This experiment reinforces our first observation of Rg in a terrestrial material. As before it is concluded that a long-lived isomeric state exists in 261Rg and that it probably belongs to a new class of isomeric states, namely high spin super- or hyperdeformed isomeric states.