A new technique for in situ measurements of erosion and redeposition in a single discharge
Based on the very different refractive constants of quartz substrates (about 1.5) and of amorphous deposits (above 1.7) collected in the scrape-off layer of TEXTOR, in situ reflectometry has been developed in order to determine the growth rates. Laboratory experiments comparing the light intensities reflected from the rear side of the system glass/deposit to the theoretically calculated reflectivity demonstrate the feasibility of the technique. The optical constants needed are determined ex situ by ellipsometry. For the application to TEXTOR, the Stockholm collector probe system has been equipped with fibre optic light guides which end behind quartz substrates carried by a replaceable graphite head. This arrangement avoids disturbance due to vibration or to observations over long distances.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 196-198 (1992) pp. 1101-1105
Record Number: 199310251 / Last updated on: 1994-11-29
Original language: en
Available languages: en