Sputtering of tungsten by oxygen at temperatures up to 1900 K

W erosion due to low energy O+ and D+ impact

“…The sputtering yields for these oxidised W targets were very small, %2 · 10 À4 W/D þ , but significantly higher than observed without the addition of O 2 . Above the threshold energy, the addition of O 2 appeared to reduce the sputtering yield, which is similar to the results of Hechtl et al [2,3] for O þ sputtering of W.…”

“…These experiments were performed in three different accelerator systems, and produced sputtering yields that varied by as much as an order of magnitude, apparently due to variations in the surface composition. The results from experiments with tungsten at 1900 K were in good agreement with their TRIM.SP calculations [3] for physical sputtering of a clean W surface by O þ . At lower temperatures, the calculations were made to match the data by increasing the oxygen content of the surface.…”

“…The resultant sputtering yield is 1.0 (±0.2) W atoms removed per incident O þ , which is in good agreement with TRIM 2000 [9] calculations for a surface containing about 5 at.% oxygen. However, this value is somewhat larger than the value of 0.69 calculated by Hechtl et al [3] for pure W (using TRIM.SP, a modified version of TRIM, by Aratari and Eckstein [10]). The difference is attributed to different stopping powers: TRIM 2000 uses newer data.…”

“…Tungsten sputtering by oxygen was measured by Hechtl et al [2,3] as a function of target temperature and ion energy, using mass-loss measurements. These experiments were performed in three different accelerator systems, and produced sputtering yields that varied by as much as an order of magnitude, apparently due to variations in the surface composition.…”

Plasma-material interactions in current tokamaks and their implications for next step fusion reactors

“…However, the enhanced erosion due to WO 3 appears to be a small effect that could not be observed during oxygen ion sputtering even at temperatures of up to 1900 K [312]. Sputtering by hydrogen isotopes near the sputtering threshold energy results in such small yield values, that the additional release of oxide molecules during simultaneous impact of hydrogen and oxygen can be observed [313].…”