Validation of the calibration strategy of the DSSC X-ray imager with a pulsed proton beam

The DePFET Sensor with Signal Compression (DSSC) is an ultra-fast, large area X-ray imager presently being developed for the European XFEL. The demanding conditions at XFEL require the qualification of the individual pixel response over the full dynamics with adequate accuracy. We used bunches of mono-energetic protons (n = 1, 2, 3, ... ) as an absolute reference to validate the energy calibration of the DSSC pixel response over the full dynamics, normally achieved by means of electrical pulsing, X-ray reference lines and/or optical injection (e.g. IR laser).