@article{oai:repo.qst.go.jp:00082391,
 author = {Eiichi, Yatsuka and Torimoto, Kazuhiro and Masao, Ishikawa and Takaki, Hatae and Eiichi, Yatsuka and Torimoto, Kazuhiro and Masao, Ishikawa and Takaki, Hatae},
 journal = {fusion engineering and design},
 month = {Jun},
 note = {This paper reports the gamma-ray irradiation effects on optical coatings and polarizers to be used in the ITERedge Thomson scattering system (ETS). Outside a diagnostic port-plug, in the Interspace, a total dose of the orderof 1 MGy is expected through 20 years of ITER operation. In this study, gamma-ray irradiation experiments wereperformed 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-re-flection (AR) and high-reflection (HR) coatings at the laser wavelengths after gamma-ray irradiation were in-vestigated. LIDT of AR coating for 0° injections was more likely higher for the irradiated samples at a wavelengthof 1064 nm. Regarding HR coatings, LIDT was not noticeably degraded by gamma-ray irradiation. Regardingpolarizers, no degradation of transmission and extinction ratio was observed at visible and near infrared wa-velength ranges when a wire-grid polarizer substrate is made of fused silica. Since a signal of ETS is almostlinearly polarized, a wire-grid polarizer enables to improve signal to noise ratio of electron temperature anddensity measurements by Thomson scattering in ITER.},
 title = {Gamma-ray irradiation effects on optical coatings and polarizers for edge Thomson scattering system in ITER},
 volume = {160},
 year = {2020}
}