Evaluation of in-situ coated boron film in JT-60U

In JT-60 Upgrade (JT-60U), in-situ boron coating of the first wall (boronization) using decarborane has been performed in order to reduce plasma impurities. The evaluation of the properties of the coated boron film produced by boronization, such as the film thickness and its uniformity along the toroidal direction and the atomic composition in the film including hydrogen concentration has been carried out. For this purpose two sets of portable sample stage system, by which probe sample can be inserted into the same level as the first wall surface, have been made and attached to the upper ports of the JT-60U vacuum vessel which are toroidally separated by 180 degrees each other. The present report describes the newly-developed portable sample stage system, its application to JT-60U boronization session and the evaluation results of the properties of the coated boron film. (author)