Journal Article

FZJ-2019-02743

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png On the use of rhodium mirrors for optical diagnostics in ITER

Mertens, P. (Corresponding author)FZJ* ; Boman, R. ; Dickheuer, S.FZJ* ; Krasikov, Y.FZJ* ; Krimmer, A.FZJ* ; Leichtle, D. ; Liegeois, K. ; Linsmeier, C.FZJ* ; Litnovsky, A.FZJ* ; Marchuk, O.Extern*FZJ* ; Rasinski, M.FZJ* ; De Bock, M.

2019
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.fusengdes.2019.04.031

Abstract: The first mirrors of optical diagnostics in ITER are exposed to high radiation and fluxes of particles which escape the plasma, in the order of $10^{20} m^{−2}s^{−1}$. At the position of the mirror, the flux may still reach about $10^{18} m^{−2}s^{−1}$. First mirrors are thus the most vulnerable in-vessel optical components, being subject to erosion, esp. by fast charge-exchange neutrals, or to deposition of impurities at flux rates which can reach 0.05 nm/s. The material selected for the reflecting surface must combine a high optical reflectivity in a wide spectral range and a sufficient resistance to physical sputtering during normal operation and during mirror cleaning discharges, if any is installed. Rhodium ($^{103}Rh$) was identified early as a possible or even promising candidate. It combines several attractive properties, for instance a mass which leads in most cases to low sputtering yields together with an optical reflectance ($\mathscr{R}_{Rh}≈75\%$) which is much higher than of some other options. $\mathscr{R}_{Rh}$is insensitive to large temperature changes. Rhodium is fairly inert and its low oxidation is an appreciable advantage in case of steam ingress events.The core-plasma CXRS diagnostic in ITER (UPP 3) have now turned to Rh as a baseline. The aim is to procure monocrystalline rhodium (SC-Rh) to mitigate the increase of the diffuse reflection with the damage due to physical sputtering.

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Contributing Institute(s):

1. Plasmaphysik (IEK-4)

Research Program(s):

1. 174 - Plasma-Wall-Interaction (POF3-174) (POF3-174)

Appears in the scientific report 2019

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Database coverage:
Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Ebsco Academic Search ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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