Kunal Dhirajlal Soni (Universität Basel)
The First Mirrors (FMs) in ITER diagnostic systems would be subject to deposition of material from the first wall (Be and W), which would severely compromise their optical properties. For a restoration, they would be routinely cleaned using RF discharges. The FMs would also be DC-grounded via a RF quarter wavelength filter, which significantly increases the plasma potential (from 30 V to over 100 V). This leads to an increased sputtering of the walls as well as their deposition on the FMs, reducing the plasma cleaning efficiency. In this contribution, we discuss various strategies experimented in ITER relevant mockup, to minimize wall sputtering and enhance plasma cleaning of DC-grounded FMs.
Kunal Dhirajlal Soni (Universität Basel) Rodrigo Antunes (University of Basel) Dr Lucas Moser (ITER Organisation) Dr Pavel Shigin (ITER Organisation) Dr Roger Reichle (ITER Organisation) Mr Roland Steiner (University of Basel) Dr Laurent Marot (University of Basel) Prof. Ernst Meyer (University of Basel)