Temperature effect on hydrocarbon deposition on molybdenum mirrors under ITER-relevant long-term plasma operation

TitleTemperature effect on hydrocarbon deposition on molybdenum mirrors under ITER-relevant long-term plasma operation
Publication TypeJournal Article
Year of Publication2009
AuthorsJ. Rapp, G.J van Rooij, A. Litnovsky, L. Marot, G. De Temmerman, J. Westerhout, E. Zoethout
JournalPhysica Scripta
VolumeT138
Pagination4
Date PublishedDec
Type of ArticleProceedings Paper
ISBN Number0031-8949
Accession NumberISI:000273199200068
KeywordsDIAGNOSTIC MIRRORS, divertor, EROSION, EXPOSURE
Abstract

Optical diagnostics in ITER will rely on mirrors near the plasma and the deterioration of the reflectivity is a concern. The effect of temperature on the deposition efficiency of hydrocarbons under long-term operation conditions similar to ITER was investigated in the linear plasma generator Pilot-PSI. Polycrystalline molybdenum mirrors were exposed for 30 min in the background of methane seeded argon plasma at 210, 340 and 490 degrees C. The surface and the optical properties of the mirrors were characterized before and after exposure by reflectivity and polarization measurements and x-ray photoelectron spectroscopy. The 210 degrees C mirror contained 10(-7) m thick deposits, which deteriorated the optical properties. Both the 340 and 490 degrees C mirrors had negligible deposits. Where the 340 degrees C mirror retained its original optical properties, the reflectivity of the 490 degrees C mirror was decreased in the UV-visible and in the near-infrared wavelength region due to carbide formation.

URL<Go to ISI>://000273199200068
Division

Fusion Physics

PID

78389aff34a8bd84e6f16215a88ca05d

Alternate TitlePhys. Scr.

Go back one page.