Progresses in development of the ITER edge Thomson scattering system

ITER周辺トムソン散乱計測装置開発の進展

谷塚 英一; Bassan, M.*; 波多江 仰紀; 石川 正男; 嶋田 恭彦; Vayakis, G.*; Walsh, M.*; Scannell, R.*; Huxford, R.*; Bilkova, P.*; Bohm, P.*; Aftanas, M.*; 伊丹 潔

Yatsuka, Eiichi; Bassan, M.*; Hatae, Takaki; Ishikawa, Masao; Shimada, Takahiko; Vayakis, G.*; Walsh, M.*; Scannell, R.*; Huxford, R.*; Bilkova, P.*; Bohm, P.*; Aftanas, M.*; Itami, Kiyoshi

In ITER, the edge Thomson scattering system (ETS) is one of the primary diagnostic systems for measuring electron temperature and electron density profiles of edge plasma. In order to provide a high throughput of scattered light against a low throughput of neutron and ray from plasma, collection optics with a labyrinthine optical path in the port plug was designed. A combination of in-situ calibration (using two lasers with different wavelengths) and periodic calibration (using a super-continuum light source illuminating shutter rear-plate covered with a diffusive material) would provide accurate measurements in ITER against the degradation of spectral transmissivity due to the harsh radiation environment and sputtering/contamination of the first mirror. Specifications of subsystems were determined from assessments of measurement error. It was confirmed that the ETS will work in ITER with the specifications achieved by present technologies.