In-situ calibration of the spectral transmissivity of Thomson scattering measurements

トムソン散乱計測における分光透過率その場較正法

谷塚 英一

Yatsuka, Eiichi

Calibration of the spectral transmissivity is one of the most crusial issues for the Thomson scattering system in ITER plasmas. However, since the vacuum vessel will be radioactivated, it is very hard to calibrate by conventional methods that uses a known light source at the measurement point. In addition, the calibration needs to be carried out frequently because the deterioration of the transmissivity will occur due to the neutron and -ray irradiation. Availability of the - calibration method by injecting 2 lasers has been investigated. It depends on the combination of the spectrometor, wavelengths of the 2 lasers, electron temperature and electron density at the calibration. If we assume the edge Thomson scattering system in ITER, the ruby laser is promising, and 1.5 keV of and of is enough to calibrate the spectral transmissivity.