Irradiation of KU1 and KS-4V substrate SiO2 overcoated Al mirrors

Piedad Martin, Teresa Hernandez, Andrei Goussarov, Eric R. Hodgson, Andrey M. Litnovsky, Mario Di Fino, Francesco Orsitto

    Research outputpeer-review

    1 Scopus citations

    Abstract

    Previous work on overcoated dielectric mirrors identified several radiation problems; UV-visible reflectivity degradation, unreliability of manufacturers coating specifications, and conversion of SiO coatings to SiO2 leading to swelling and cracking, and hence possible corrosion during LOCAs (loss of coolant accident). We report the results obtained for gamma and neutron irradiation of prototype mirrors with KU1 and KS-4V high purity silicas replacing the standard Pyrex substrate to overcome the problem of activation due to high impurity content. To avoid the SiO to SiO2 conversion problem, the Al layer has been overcoated with SiO2. The mirrors show high reflectivity (>80%) down to 200 nm. After gamma irradiation at 170 C in a dry nitrogen atmosphere to 10 MGy, no degradation in reflectivity was observed. They were then neutron irradiated in vacuum at 35 C to 6.8 × 1016 n/cm2 (fast fluence) and reflectivity examined with a specially designed spectrometer system with a remote integrating sphere for hot cell use. Again no degradation in reflectivity was observed.

    Original languageEnglish
    Pages (from-to)1224-1227
    Number of pages4
    Journalfusion engineering and design
    Volume88
    Issue number6-8
    DOIs
    StatePublished - 2013

    ASJC Scopus subject areas

    • Civil and Structural Engineering
    • Nuclear Energy and Engineering
    • Materials Science(all)
    • Mechanical Engineering

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