Calibration of soft-X-ray spectrometer for measurements of electron temperature from plasma bremsstrahlung spectra in the FT-2 tokamak

A soft X-ray spectrometer based on a silicon drift detector is installed in the FT-2 tokamak for measurements of bremsstrahlung spectra at output count rates of 3 $\cdot$ 10$^6$ s$^{-1}$ and energy resolution of $<$ 150 eV. The spectrometer is developed for measurements of fast dynamic of the distribution function of high energy electrons. It could be used for measurements of electron temperature from the spectral shape in the low energy range. Spectral calibration of the spectrometer and determination of thickness of beryllium window of the detector are performed for this goal. Obtained results are used for modelling bremsstrahlung spectra and their comparison to that measured in FT-2 plasma.