An imaging spectroscopy becomes one of the fundamental method of the radial profile study of the light impurities line emission of high temperature plasmas. The application of the spherical dispersion elements (as diffraction grids and a multilayer mirrors) makes it possible an image of the radial profile of the chosen spectral line intensity.

The line spectrum measurements of the light impurities emission in 50 - 200 nm wavelength range at different plasmas equipment (tokamak CASTOR and GOL-3) has been provided by Seya-Namioka spectrometer equipped by spherical diffraction grid and a two dimensional detection system. The especial arrangement of the optical trace has been used for high imaging resolution in plasma radial direction.

The novel diagnostic method can provide the way of impurity transport investigation [1]. It is well known, the transport effects lead to some deviations of the radial distribution of the line emission density from those calculated using pure coronal equilibrium. They can be deduced from chordal measurements of the radial profiles of the spectral line intensity and or intensity ratios of spectral lines of different ionisation stages both measured by chord-integrating spectrometer.