An overview of the comprehensive First Mirror Test in JET with ITER-like wall

D. Ivanova, M. Rubel, A. Widdowson, P. Petersson, Jari Likonen, L. Marot, E. Alves, A. Garcia-Carrasco, G. Pintsuk, JET-EFDA Contributors

    Research output: Contribution to journalArticleScientificpeer-review

    36 Citations (Scopus)

    Abstract

    The First Mirror Test in Joint European Torus (JET) with the International Thermonuclear Experimental Reactor-like wall was performed with polycrystalline molybdenum mirrors. Two major types of experiments were done. Using a reciprocating probe system in the main chamber, a short-term exposure was made during a 0.3 h plasma operation in 71 discharges. The impact on reflectivity was negligible. In a long-term experiment lasting 19 h with 13 h of X-point plasma, 20 Mo mirrors were exposed, including four coated with a 1 µm-thick Rh layer. Optical performance of all mirrors exposed in the divertor was degraded by up to 80% because of beryllium, carbon and tungsten co-deposits on surfaces. Total reflectivity of most Mo mirrors facing plasma in the main chamber was only slightly affected in the spectral range 400-1600 nm, while the Rh-coated mirror lost its high original reflectivity by 30%, thus decreasing to the level typical of molybdenum surfaces. Specular reflectivity was decreased most strongly in the 250-400 nm UV range. Surface measurements with x-ray photoelectron spectroscopy and depth profiling with secondary ion mass spectrometry and heavy-ion elastic recoil detection analysis (ERDA) revealed that the very surface region on both types of mirrors had been modified by neutrals, resulting eventually in the composition change: Be, C, D at the level below 1 * 1016 cm-2 mixed with traces of Ni, Fe in the layer 10-30 nm thick. On several exposed mirrors, the original matrix material (Mo) remained as the major constituent of the modified layer. The data obtained in two major phases of the JET operation with carbon and full metal walls are compared. The implications of these results for first mirrors and their maintenance in a reactor-class device are discussed.
    Original languageEnglish
    Article number014011
    JournalPhysica Scripta
    Issue numberT159
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Joint European Torus
    Mirror
    Torus
    mirrors
    Reflectivity
    reflectance
    Plasma
    Reactor
    molybdenum
    Carbon
    chambers
    reactors
    matrix materials
    X-ray Spectroscopy
    carbon
    Mass Spectrometry
    beryllium
    Profiling
    Range of data
    x ray spectroscopy

    Cite this

    Ivanova, D., Rubel, M., Widdowson, A., Petersson, P., Likonen, J., Marot, L., ... Contributors, JET-EFDA. (2014). An overview of the comprehensive First Mirror Test in JET with ITER-like wall. Physica Scripta, (T159), [014011]. https://doi.org/10.1088/0031-8949/2014/T159/014011
    Ivanova, D. ; Rubel, M. ; Widdowson, A. ; Petersson, P. ; Likonen, Jari ; Marot, L. ; Alves, E. ; Garcia-Carrasco, A. ; Pintsuk, G. ; Contributors, JET-EFDA. / An overview of the comprehensive First Mirror Test in JET with ITER-like wall. In: Physica Scripta. 2014 ; No. T159.
    @article{d5fed99888f74060a29fba1ce4f60dc3,
    title = "An overview of the comprehensive First Mirror Test in JET with ITER-like wall",
    abstract = "The First Mirror Test in Joint European Torus (JET) with the International Thermonuclear Experimental Reactor-like wall was performed with polycrystalline molybdenum mirrors. Two major types of experiments were done. Using a reciprocating probe system in the main chamber, a short-term exposure was made during a 0.3 h plasma operation in 71 discharges. The impact on reflectivity was negligible. In a long-term experiment lasting 19 h with 13 h of X-point plasma, 20 Mo mirrors were exposed, including four coated with a 1 µm-thick Rh layer. Optical performance of all mirrors exposed in the divertor was degraded by up to 80{\%} because of beryllium, carbon and tungsten co-deposits on surfaces. Total reflectivity of most Mo mirrors facing plasma in the main chamber was only slightly affected in the spectral range 400-1600 nm, while the Rh-coated mirror lost its high original reflectivity by 30{\%}, thus decreasing to the level typical of molybdenum surfaces. Specular reflectivity was decreased most strongly in the 250-400 nm UV range. Surface measurements with x-ray photoelectron spectroscopy and depth profiling with secondary ion mass spectrometry and heavy-ion elastic recoil detection analysis (ERDA) revealed that the very surface region on both types of mirrors had been modified by neutrals, resulting eventually in the composition change: Be, C, D at the level below 1 * 1016 cm-2 mixed with traces of Ni, Fe in the layer 10-30 nm thick. On several exposed mirrors, the original matrix material (Mo) remained as the major constituent of the modified layer. The data obtained in two major phases of the JET operation with carbon and full metal walls are compared. The implications of these results for first mirrors and their maintenance in a reactor-class device are discussed.",
    author = "D. Ivanova and M. Rubel and A. Widdowson and P. Petersson and Jari Likonen and L. Marot and E. Alves and A. Garcia-Carrasco and G. Pintsuk and JET-EFDA Contributors",
    year = "2014",
    doi = "10.1088/0031-8949/2014/T159/014011",
    language = "English",
    journal = "Physica Scripta",
    issn = "0031-8949",
    publisher = "Institute of Physics IOP",
    number = "T159",

    }

    Ivanova, D, Rubel, M, Widdowson, A, Petersson, P, Likonen, J, Marot, L, Alves, E, Garcia-Carrasco, A, Pintsuk, G & Contributors, JET-EFDA 2014, 'An overview of the comprehensive First Mirror Test in JET with ITER-like wall', Physica Scripta, no. T159, 014011. https://doi.org/10.1088/0031-8949/2014/T159/014011

    An overview of the comprehensive First Mirror Test in JET with ITER-like wall. / Ivanova, D.; Rubel, M.; Widdowson, A.; Petersson, P.; Likonen, Jari; Marot, L.; Alves, E.; Garcia-Carrasco, A.; Pintsuk, G.; Contributors, JET-EFDA.

    In: Physica Scripta, No. T159, 014011, 2014.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - An overview of the comprehensive First Mirror Test in JET with ITER-like wall

    AU - Ivanova, D.

    AU - Rubel, M.

    AU - Widdowson, A.

    AU - Petersson, P.

    AU - Likonen, Jari

    AU - Marot, L.

    AU - Alves, E.

    AU - Garcia-Carrasco, A.

    AU - Pintsuk, G.

    AU - Contributors, JET-EFDA

    PY - 2014

    Y1 - 2014

    N2 - The First Mirror Test in Joint European Torus (JET) with the International Thermonuclear Experimental Reactor-like wall was performed with polycrystalline molybdenum mirrors. Two major types of experiments were done. Using a reciprocating probe system in the main chamber, a short-term exposure was made during a 0.3 h plasma operation in 71 discharges. The impact on reflectivity was negligible. In a long-term experiment lasting 19 h with 13 h of X-point plasma, 20 Mo mirrors were exposed, including four coated with a 1 µm-thick Rh layer. Optical performance of all mirrors exposed in the divertor was degraded by up to 80% because of beryllium, carbon and tungsten co-deposits on surfaces. Total reflectivity of most Mo mirrors facing plasma in the main chamber was only slightly affected in the spectral range 400-1600 nm, while the Rh-coated mirror lost its high original reflectivity by 30%, thus decreasing to the level typical of molybdenum surfaces. Specular reflectivity was decreased most strongly in the 250-400 nm UV range. Surface measurements with x-ray photoelectron spectroscopy and depth profiling with secondary ion mass spectrometry and heavy-ion elastic recoil detection analysis (ERDA) revealed that the very surface region on both types of mirrors had been modified by neutrals, resulting eventually in the composition change: Be, C, D at the level below 1 * 1016 cm-2 mixed with traces of Ni, Fe in the layer 10-30 nm thick. On several exposed mirrors, the original matrix material (Mo) remained as the major constituent of the modified layer. The data obtained in two major phases of the JET operation with carbon and full metal walls are compared. The implications of these results for first mirrors and their maintenance in a reactor-class device are discussed.

    AB - The First Mirror Test in Joint European Torus (JET) with the International Thermonuclear Experimental Reactor-like wall was performed with polycrystalline molybdenum mirrors. Two major types of experiments were done. Using a reciprocating probe system in the main chamber, a short-term exposure was made during a 0.3 h plasma operation in 71 discharges. The impact on reflectivity was negligible. In a long-term experiment lasting 19 h with 13 h of X-point plasma, 20 Mo mirrors were exposed, including four coated with a 1 µm-thick Rh layer. Optical performance of all mirrors exposed in the divertor was degraded by up to 80% because of beryllium, carbon and tungsten co-deposits on surfaces. Total reflectivity of most Mo mirrors facing plasma in the main chamber was only slightly affected in the spectral range 400-1600 nm, while the Rh-coated mirror lost its high original reflectivity by 30%, thus decreasing to the level typical of molybdenum surfaces. Specular reflectivity was decreased most strongly in the 250-400 nm UV range. Surface measurements with x-ray photoelectron spectroscopy and depth profiling with secondary ion mass spectrometry and heavy-ion elastic recoil detection analysis (ERDA) revealed that the very surface region on both types of mirrors had been modified by neutrals, resulting eventually in the composition change: Be, C, D at the level below 1 * 1016 cm-2 mixed with traces of Ni, Fe in the layer 10-30 nm thick. On several exposed mirrors, the original matrix material (Mo) remained as the major constituent of the modified layer. The data obtained in two major phases of the JET operation with carbon and full metal walls are compared. The implications of these results for first mirrors and their maintenance in a reactor-class device are discussed.

    U2 - 10.1088/0031-8949/2014/T159/014011

    DO - 10.1088/0031-8949/2014/T159/014011

    M3 - Article

    JO - Physica Scripta

    JF - Physica Scripta

    SN - 0031-8949

    IS - T159

    M1 - 014011

    ER -