First tests of molybdenum mirrors for ITER diagnostics in DIII-D divertor

D. L. Rudakov*, J. A. Boedo, R. A. Moyer, A. Litnovsky, V. Philipps, P. Wienhold, S. L. Allen, M. E. Fenstermacher, M. Groth, C. J. Lasnier, R. L. Boivin, N. H. Brooks, A. W. Leonard, W. P. West, C. P C Wong, A. G. McLean, P. C. Stangeby, G. De Temmerman, W. R. Wampler, J. G. Watkins

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)

Abstract

Metallic mirrors will be used in ITER for optical diagnostics working in different spectral ranges. Their optical properties will change with time due to erosion, deposition, and particle implantation. First tests of molybdenum mirrors were performed in the DIII-D divertor under deposition-dominated conditions. Two sets of mirrors recessed 2 cm below the divertor floor in the private flux region were exposed to a series of identical, lower-single-null, ELMing (featuring edge localized modes) H-mode discharges with detached plasma conditions in both divertor legs. The first set of mirrors was exposed at ambient temperature, while the second set was preheated to temperatures between 140 and 80 °C. During the exposures mirrors in both sets were additionally heated by radiation from the plasma. The nonheated mirrors exhibited net carbon deposition at a rate of up to 3.7 nms and suffered a significant drop in reflectivity. Net carbon deposition rate on the preheated mirrors was a factor of 30-100 lower and their optical reflectivity in the wave range above 500 nm was essentially preserved.

Original languageEnglish
Article number10F126
Pages (from-to)1-4
Number of pages4
JournalReview of Scientific Instruments
Volume77
Issue number10
DOIs
Publication statusPublished - 2006
MoE publication typeA1 Journal article-refereed

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