Helium-induced morphology evolution in tungsten under thermal treatment

Thermal Accommodation of the Helium Isotopes on Clean Tungsten Surfaces

In the last years considerable effort, especially from the theoretical side, has been invested to come to a better understanding of the energy and momentum exchange which takes place upon impact of gas particles on solid surfaces1. The examination of the proposed models is ham­ pered by the fact that reliable experimental data are still scarce, which is mainly due to the very strong influence o...

Morphologies of tungsten nanotendrils grown under helium exposure

Nanotendril "fuzz" will grow under He bombardment under tokamak-relevant conditions on tungsten plasma-facing materials in a magnetic fusion energy device. We have grown tungsten nanotendrils at low (50 eV) and high (12 keV) He bombardment energy, in the range 900-1000 °C, and characterized them using electron microscopy. Low energy tendrils are finer (~22 nm diameter) than high-energy tendrils...

Helium Cooled Tungsten Heat Sinks

Evolution of dopant-induced helium nanoplasmas

Two-component nanoplasmas generated by strong-field ionization of doped helium nanodroplets are studied in a pump–probe experiment using few-cycle laser pulses in combination with molecular dynamics simulations. High yields of helium ions and a pronounced resonance structure in the pump–probe transients which is droplet size dependent reveal the evolution of the dopant-induced helium nanoplasma...

Helium bubble formation in ultrafine and nanocrystalline tungsten under different extreme conditions

We have investigated the effects of helium ion irradiation energy and sample temperature on the performance of grain boundaries as helium sinks in ultrafine grained and nanocrystalline tungsten. Irradiations were performed at displacement and non-displacement energies and at temperatures above and below that required for vacancy migration. Microstructural investigations were performed using Tra...