Imaging x-ray crystal spectrometers for KSTAR

Two x-ray imaging crystal spectrometers are presently designed for the KSTAR tokamak. The instruments will provide temporally and spatially resolved spectra of heliumlike argon (or krypton) from a large cross section of the plasma. The spectral data will be used for profile measurements—both within and perpendicular to the horizontal midplane of KSTAR—of the ion and electron temperatures, the rotation velocity, and the ionization equilibrium. Each spectrometer will consist of a spherically bent quartz crystal and large area two-dimensional position-sensitive multiwire proportional counter. The article presents the design for the KSTAR x-ray imaging crystal spectrometers, and the fabrication and initial test results from the large area two-dimensional multiwire proportional counter.