Strategy for calibrating the non-linear gain 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 design goal is to achieve at the same time single photon detection and high dynamic range, both for photon energies down to 0.5 keV and read-out speeds up to 4.5 MHz. Realization of this goal requires an accurate calibration of the non-linear system gain (NLSG), i.e. of the non-linear dependence of the digital DSSC output signal on the input signal charge generated by incident photons, over the full dynamic range of the detector. We present an overview of our basic strategy for calibrating the NLSG. The feasibility of our calibration strategy is demonstrated using our system simulation package, which is briefly described. Finally, we demonstrate the DSSC capabilities by simulating the measurement of a T4 virus diffraction image as recorded at the Linac Coherent Light Source.