Speaker
Description
The DSSC (DEPFET Sensor with Signal Compression) is a large-area, ultra-fast (4.5 MHz), soft X-ray (0.25 - 6 keV) camera developed for operation at the European X-ray Free Electron Laser. The pixel design features low-noise DEPFET technology with a modified doping profile that induces a signal-dependent gain, extending the detector's dynamic range. The full camera comprises 16 front-end modules, each containing 512$\times$128 hexagonal pixels of side length 136 $\mu$m, built on 725 $\mu$m high-resistivity depleted silicon. Previous studies of a single DSSC module have demonstrated low noise ($<$10 e$^{-}$) and high dynamic range (10$^{4}$). For future user operation, all 16 modules of the full 1-megapixel camera must be extensively characterised. Calibration data have been collected at the European XFEL to explore the full dynamic range of the DSSC for various gain configurations. Using PulXar, a laboratory X-ray source that mimics the timing structure of the European XFEL, the low-intensity, linear region of the detector response has been measured. For the high-intensity, non-linear region, the DSSC was installed at one of the European XFEL beamlines. Initial results show stable and uniform performance across all modules of the camera. Measurements of noise and gain are presented, and camera assembly, facility integration, and user operation are discussed.