Calibration of the non-linear system response of a prototype set-up of the DSSC detector for the European XFEL

The DSSC (DEPFET Sensor with Signal Compression) is a new instrument with non-linear compression of the input signal in the sensor and with parallel signal processing (filtering, linear amplification, and digitization) for all pixels. The DSSC will serve as 2d imaging detector at the European X-ray Free Electron Laser (XFEL.EU) currently under construction in Hamburg, Germany. The DSSC design goal is to achieve at the same time single photon detection and high dynamic range of about 104 photons, both for photon energies down to 0.5 keY and read-out speeds up to 4.5 MHz. Realization of this goal requires an accurate calibration of the non-linear system response (NLSR) over the full dynamic range of the detector. We present our strategy for calibrating the NLSR, for each of the 1024 × 1024 DSSC pixels, in the laboratory. The feasibility of our calibration strategy is demonstrated experimentally by calibrating the NLSR of a DSSC prototype set-up consisting of a prototype DEPFET sensor with non-linear signal compression connected to a prototype read-out ASIC.