Upgrade of poloidal and tangential x-ray imaging crystal spectrometers on EAST tokamak

The Poloidal and Tangential X-ray imaging Crystal Spectrometers (PXCS and TXCS) were developed on Experimental Advanced Superconducting Tokamak (EAST) to provide spatially and temporally resolved plasmas ion temperature (T_i), electron temperature (T_e) and rotation velocity (poloidal- and toroidal-, V_p and V_t) profiles. Each spectrometer consisted of a spherically curved crystal and a CMOS pixelated X-ray Detector. Both spectrometers have recently been upgraded to enhance their measurement capabilities and stabilities. A He-like argon crystal (2d=4.913Å) is deployed on the TXCS and a double-crystal assembly including a He-like argon (2d=4.913Å) crystal and a Ne-like xenon (2d=6.686Å) crystal is deployed on the PXCS. To obtain the optimal spatial resolution, the distance from the crystal to the detector and to the plasma center are modified. Meanwhile, the projection angle of the TXCS sightline to the major radial direction is increased from ~ 22.5º to ~ 29.5ºin order to view the plasma with more tangential component. The XCS server is moved from the EAST tokamak hall to an outside lab to avoid harsh electromagnetic environment and thus enhance stability. Finally, the experimental results from the upgraded XCS systems are presented. New spectral lines of Zinc-like, Copper like and Gallium-like tungsten are identified, which are diffracted by the He-like argon crystal. High-quality He-like argon and Ne-like xenon spectra are observed simultaneously on one detector for measurements of plasmas with wide temperature ranges. Comparison of the Ti- and Vt- profiles measured by TXCS with those measured by charge exchange recombination spectroscopy (CXRS) shows that the results are in well agreement, verifying the reliability of the upgrade of the spectrometers.