Development of x-ray imaging diagnostics on Experimental Advanced Superconducting Tokamak using Timepix3 detector.

An x-ray imaging diagnostic system using the Timepix3 detector has recently been developed and installed on the Experimental Advanced Superconducting Tokamak (EAST). The diagnostic system measures the temporal evolution, spatial distribution, and energy spectrum of x-ray signals during plasma discharge with a 16° diagonal field of view, spatial resolution of 4 mm, and broad spectral-energy response range (5-200 keV). Equipped with event-driven capability, the Timepix3 detector captures the coordinates, energy, and arrival time of each photon event with a temporal resolution of 1.56 ns. Herein, the energy resolution and spatial resolution performances of the detector were tested in counting and time-over-threshold modes. The energy resolution of the detector in both modes was within 5 keV. The temporal resolution of the detector and the temporal evolution of x-ray signals were analyzed during plasma discharge experiments on the EAST, harnessing the event-driven capability of the detector for latter analysis. Furthermore, the detector-measured signals were compared with conventional diagnostic signals, confirming the reliability of the Timepix3 detector. Overall, this paper presents the parameter testing results and preliminary experimental diagnostic outcomes.