Measurement of thickness of film deposited on the plasma-facing wall in the QUEST tokamak by colorimetry

Z. Wang, K. Hanada, N. Yoshida, T. Shimoji, M. Miyamoto, Y. Oya, H. Zushi, H. Idei, K. Nakamura, A. Fujisawa, Y. Nagashima, M. Hasegawa, S. Kawasaki, A. Higashijima, H. Nakashima, T. Nagata, A. Kawaguchi, T. Fujiwara, K. Araki, O. MitaraiA. Fukuyama, Y. Takase, K. Matsumoto

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8 Citations (Scopus)


After several experimental campaigns in the Kyushu University Experiment with Steady-state Spherical Tokamak (QUEST), the originally stainless steel plasma-facing wall (PFW) becomes completely covered with a deposited film composed of mixture materials, such as iron, chromium, carbon, and tungsten. In this work, an innovative colorimetry-based method was developed to measure the thickness of the deposited film on the actual QUEST wall. Because the optical constants of the deposited film on the PFW were position-dependent and the extinction coefficient k1 was about 1.0-2.0, which made the probing light not penetrate through some thick deposited films, the colorimetry method developed can only provide a rough value range of thickness of the metal-containing film deposited on the actual PFW in QUEST. However, the use of colorimetry is of great benefit to large-area inspections and to radioactive materials in future fusion devices that will be strictly prohibited from being taken out of the limited area.

Original languageEnglish
Article number093502
JournalReview of Scientific Instruments
Issue number9
Publication statusPublished - Sept 1 2017

All Science Journal Classification (ASJC) codes

  • Instrumentation


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