%0 Journal Article
%A Mertens, Philippe
%A Boman, Romain
%A Dickheuer, Sven
%A Krasikov, Yury
%A Krimmer, Andreas
%A Leichtle, Dieter
%A Liegeois, Kim
%A Linsmeier, Christian
%A Litnovsky, Andrey
%A Marchuk, Oleksander
%A Rasinski, Marcin
%A De Bock, Maarten
%T On the use of rhodium mirrors for optical diagnostics in ITER
%J Fusion engineering and design
%V 146
%N B
%@ 0920-3796
%C New York, NY [u.a.]
%I Elsevier
%M FZJ-2019-02743
%P 2514-2518
%D 2019
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000488313700241
%R 10.1016/j.fusengdes.2019.04.031
%U https://juser.fz-juelich.de/record/862421