Rotational Raman scattering of hydrogen for calibrating a Thomson scattering device

The anti-Stokes rotational Raman scattering from hydrogen gas (60–200 Torr at 293 K) is used to calibrate the intensity of the Thomson scattered signal from the JFT-2M tokamak plasma by the incidence of ruby laser light. The normalized sensitivities as well as the Raman constant are obtained by the Raman scattering experiment. The electron temperature and density profiles are calculated with the calibration constant obtained by the Raman scattered light and the LED light; the error of electron density depends on the uncertainty of the differential Raman cross section of hydrogen gas, the gas filling density, the electron temperature, and the photoelectron statistics.