First boronization in KSTAR: Experiences on carborane

Abstract First boronization was performed in KSTAR tokamak during 2009 campaign in order to reduce oxygen impurities and to lower the power loss due to radiation. We report the results from the experiences on carborane during the first boronization in KSTAR. After the boronization, H 2 O and O 2 level in the vacuum vessel are reduced significantly. The characteristics of the deposited thin films were analyzed by variable angle spectroscopic ellipsometry, XPS, and AES. ∼1.78 × 10 16  cm −2  s −1 of carbon flux on the wall is estimated by using cavity technique.