Impurity ion radiation intensity has been studied in the GAMMA 10 plasma using both a collisional-radiative model (CR-model) and spectroscopic measurements. We have constructed absolutely calibrated soft X-ray, vacuum ultraviolet, ultraviolet and visible spectrographs for plasma diagnostics. Steady state CR-model calculation for carbon ions is used to obtain the carbon ion emissivities in the plasma. The CR-model calculation results of carbon ion radiation intensities are comparable to the results obtained by the impurity ion spectroscopy. Moreover, plasma rotation measurements are carried out in order to obtain radial electric potential profiles.