Plasma and Fusion Research

Volume 18, 2405014 (2023)

Regular Articles

Progress of Gamma Ray Irradiation Experiments on ITER Diagnostics from JADA
Sin-iti KITAZAWA, Eiichi YATSUKA, Masao ISHIKAWA, Tomohiko USHIKI, Toshihiro OIKAWA, Hiroaki OGAWA, Ryota IMAZAWA, Kunpei NOJIRI, Takanori KIKUCHI, Tomohiro YOKOZUKA, Hidetoshi MURAKAMI, Kosuke SHIMIZU, Tatsuo SUGIE, Kazuhiro TORIMOTO, Moriyoshi INAMINE, Shigehiro KONO and Yoshihiko NUNOYA
Naka Fusion Institute, National Institutes for Quantum Science and Technology (QST), Naka 311-0193, Japan
(Received 28 December 2022 / Accepted 5 February 2023 / Published 10 March 2023)


The Japan domestic agency (JADA) is responsible for procuring five diagnostic systems for ITER: the microfission chamber (MFC), poloidal polarimeter (PoPola), edge Thomson scattering (ETS), divertor impurity monitor (DIM), and divertor infrared thermography (IRTh) systems. Components of these systems that will be installed in high radiation zones must undergo radiation resistance tests to ensure reliability. The JADA diagnostic group has been conducting gamma ray irradiation experiments on diagnostic components at QST since 2018. The MFC is a neutron diagnostic system that uses uranium fission chambers, the mineral-insulated cables of which were evaluated for corrosion resistance. In-situ observations of the MFC preamplifier have been launched. The PoPola provides the plasma current profile by detecting the polarizations of far-infrared laser beams at their inlets and outlets. Irradiation tests confirmed the durability of PoPola piezo actuators. The ETS is a laser-aided diagnostic to measure electron temperature and density in plasmas from scattered spectra. Laser-induced damages to the optical elements caused by irradiation were investigated. The DIM is a spectroscopic system having a wavelength range of 200 nm to 1000 nm. The effects of irradiation on optical devices, metal mirrors, and radiation-resistant optical fibers were investigated. The IRTh is an infrared thermography system to observe the surface temperature of the divertor. The optical elements and electrical devices of the IRTh have undergone irradiation experiments. The progress of the gamma ray irradiation experiments on the ITER diagnostic systems from JADA are reported.


ITER, diagnostic system, gamma ray, MFC, PoPola, ETS, DIM, IRTh

DOI: 10.1585/pfr.18.2405014


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