Tokamak T-10 soft X-ray diagnostic

The T-10 soft X-ray imaging system consists of three pin-hole cameras arranged at one torroidal location. The 'vertical' array (θ=90o), the middle camera (θ=+30o) and the 'bottom' camera (θ=-30o) consists of 20, 19, and 19 channels, accordingly. The field of view is r/a<0.7. The spatial resolution and the spatial step are 2-2.5 cm for each array. The detectors are Si surface-barrier diodes arranged in each camera in two or three rows. The system allows to register the emission with intensity 105-109 cm-2c-1 in the photon energy range between 2.5 and 15 keV. For this energy range the soft X-ray spectrum is Maxwellian and the Kα line radiation from Cr, Fe, Ni ions is negligible (less than 10%) in the ohmic stationary stage of the T-10 discharge. The relative calibration of the channels was made by the comparison with the soft X-ray intensity profiles measured with two Si(Li) detectors scanning the plasma in vertical and horizontal directions at the stationary stage of the discharge. Temporal resolution of the system is up to 10 μsec. The local structure of the soft X-ray intensity perturbation is reconstructed by the use of the 2D-tomographic technique based on modified Cormack method. (author) 10 refs., 3 figs., 1 tab