Toroidal charge exchange recombination spectroscopy on EAST

A toroidal charge exchange recombination spectroscopy (CXRS) diagnostic, on the basis of a heating neutral beam injector (NBI), is constructed on EAST tokamak. Simulation of Spectra (SOS) code is used to design and evaluate the diagnostic performance. 30 spatial channels work simultaneously in recent experiment, which covers a radial region from 1.55m to 2.30m in the cross section. The CXRS has a radial resolution of 1–3.5cm from core to edge. The acquisition time is typically 10ms, limited by the poor photon statistics. The diagnostic can observe not only the normal C5+ emission line at 529.1nm but also any interested wavelength in the range of 400–700nm. In this work, a brief overview on the R&D and the instrument performance for the toroidal CXRS diagnostic is described, together with first results.