Measurement of Hard X-Rays on KSTAR

Hard X-ray (HXR) emission from KSTAR superconducting Tokamak has been measured during discharges which includes ECH assisted start up. Since the HXR signal indicates energetic electrons we can assume that runaway electrons are being generated. On KSTAR two tangentially arranged NaI(Tl) detectors are installed to measure the HXR intensity and energy in the forward and backward directions, respectively. We investigate the HXR emission trends in KSTAR tokamak and how the ECH heating source affects the generation of runway electrons.