Observations of He platelets during He ion irradiation in 3C SiC

In situ Observation of Microstructure Evolution in 4H-SiC under 3.5keV He Irradiation

4H-SiC was irradiated with 3.5 keV He ions using the MIAMI facility at University of Huddersfield. The evolution of microstructure and gas bubbles during the irradiation at 700°C, 800°C and 900°C was observed by in situ transmission electron microscopy. Under irradiation, isolated bubbles and bubble discs formed in the SiC matrix. Bubble discs lying on {0001} and {10-10} crystal planes were beg...

A Re-evalua[ion of [he Sokes Drif in [he Polar Summer Mesosphere

The Stokes drift argument put forth by Coy et al. (1986) to explain the monthly mean downward vertical velocities observed in the summer polar mesosphere by radars is critically re-exanfined. The size of the effect is quite sensitive to the choice of gravity wave wavenumber and phase speed. We reproduce the Coy et al. (1986) result for a monochromatic gravity wave and then generalize to a Garre...

Experimental and simulation-based investigation of He, Ne and Ar irradiation of polymers for ion microscopy

Secondary ion mass spectrometry (SIMS) on the helium ion microscope (HIM) promises higher lateral resolution than on classical SIMS instruments. However, full advantage of this new technique can only be obtained when the interaction of He(+) or Ne(+) primary ions with the sample is fully controlled. In this work we investigate how He(+) and Ne(+) bombardment influences roughness formation and p...

Effect of high-flux, low-energy He+ ion irradiation on Ta as a plasma-facing material

The goal of this work is to assess Ta as a potential plasma-facing material for future fusion reactors in terms of its response to high-flux, low-energy He+ ion irradiation. Ta samples were irradiated with 100 eV He+ ions at various fluences up to 3.5 × 1025 ions m-2 while simultaneously heated at constant temperatures in the range 823-1223 K. SEM studies show that irradiated Ta surfaces underg...

Autoionization of He and Autodetachment of He- following Bombardment by H+, H2+, He+, and He Atoms