Currently a joint experimental program is performed on the RUDI injector at the TEXTOR tokamak in a collaboration between the Budker Institute of Nuclear Physics SB RAS and the Research Center Juelich (Forschungszentrum Juelich GmbH). The diagnostic injector RUDI is used for charge-exchange recombination spectroscopy (CXRS) diagnostic at the tokamak TEXTOR. Since the spatial resolution and CXRS signal level depend on diagnostic beam divergence and beam full-energy component current density, respectively, these beam parameters should be controlled to provide stable CXRS measurements. The beam density distribution, the angular divergence and the species composition, can be measured optically by spectroscopic means. The absence of perturbations to the beam investigated is one of the main advantages of optical diagnostics.