@misc{oai:repo.qst.go.jp:00079630,
 author = {谷塚, 英一 and 鳥本, 和弘 and 石川, 正男 and 波多江, 仰紀 and Yatsuka, Eiichi and Torimoto, Kazuhiro and Ishikawa, Masao and Hatae, Takaki},
 month = {Sep},
 note = {This paper reports the gamma-ray irradiation effects on optical coatings and polarizers to be used in the ITER edge Thomson scattering system (ETS). Outside a diagnostic port-plug, in the Interspace, a total dose of the order of 1 MGy is expected through 20 years of ITER operation. In this study, gamma-ray irradiation experiments were performed up to 10 MGy. A high peak power laser beam, i.e. a pulse energy of 5 J and a pulse duration of ~4 ns, is needed for a Thomson scattering measurement in ITER. Laser-induced damage threshold (LIDT) of anti-reflection (AR) and high-reflection (HR) coatings at the laser wavelengths after gamma-ray irradiation were investigated. Contrary to expectation, LIDT of AR coating is more likely higher for the irradiated samples at a wavelength of 1064 nm. Regarding HR coatings, LIDT was not noticeably degraded by gamma-ray irradiation. Regarding polarizers, no degradation of transmission and extinction ratio was observed at visible and near infrared wavelength ranges when a wire-grid polarizer substrate is made of fused silica. Since a signal of ETS is almost linearly polarized, a wire-grid polarizer enables to improve signal to noise ratio of electron temperature and density measurements by Thomson scattering in ITER., The 14th International Symposium on Fusion Nuclear Technology},
 title = {Gamma-ray irradiation effects on optical coatings and polarizers for edge Thomson scattering system in ITER},
 year = {2019}
}