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

Abstract

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.

Vacuum Chromatography of Tl on SiO2 at the Single-Atom Level

“…In these two cases, the high kinetic energies of the recoiling evaporation residues allow them to pass through a thin entrance window, closing up the HC containment. The first option, with the projectile beam passing through the HC foil, leads to radiation (damage) enhanced diffusion, , which can severely speed up the thermal release process. For the second case, however, the current catcher setup with its 30 × 48 mm size can provide relatively high efficiencies even with the rather broad product distribution in the focal plane of a preseparator.…”

“…The current experiment combines earlier findings related to the fast thermal release of various elements from solid catcher materials , with gas-phase chromatography studies of thallium species on quartz as well as with the recently established diamond detector technology . This proof-of-principle experiment paves the way toward cleaner and faster SHE experiments that allow access to more short-lived and only moderately volatile SHEs.…”