First measurement of electron temperature from signal ratios in a double-pass Thomson scattering system

This paper presents an experimental demonstration to determine electron temperature ( T e ) with unknown spectral sensitivity (transmissivity) in a Thomson scattering system. In this method, a double-pass scattering configuration is used and the scattered lights from each pass (with different scattering angles) are measured separately. T e can be determined from the ratio of the signal intensities without knowing a real chromatic dependence in the sensitivity. Note that the wavelength range for each spectral channel must be known. This method was applied to the TST-2 Thomson scattering system. As a result, T e measured from the ratio ( T e,r ) and T e measured from a standard method ( T e,s ) showed a good agreement with 〈| T e,r − T e,s |/ T e,s 〉 = 7.3%.