Contents I. Introduction
Our consortium is developing the DSSC (DEPFET Sensor with Signal Compression) [1]: a high speed focal plane detector system for the new Eurpean XFEL (X-ray Free Electron Laser) in Hamburg [2], [3]. The instrument will be able to record X-ray images with a maximum frame rate of 4.5 MHz and to achieve a high dynamic range. This will allow coping with the very demanding pulse time structure of European XFEL. The machine will provide macro-bunches with a repetition rate of 10Hz. Every macro-bunch is composed of X-ray pulses with a temporal distance of 220 ns (Fig. 1). Our detector will be able to acquire images every 220 ns obtaining a frame rate of 4.5 MHz and high dynamic range at the same time. The number of stored frames per macro-bunch will be at least 640 with the possibility to discard bad frames thanks to an external trigger. The key properties of the system are summarized in Tab. I. Some of the reported parameters depend on the different operating conditions offered by the DSSC and are discussed in more details in Section V. X-ray bunch structure at the European XFEL. The XFEL machine generates macro-bunches with a repetition rate of 10Hz. Every macro-bunch is composed of a train of 2700 X-ray pulses with a temporal distance of 220 ns. The DSSC will be able to acquire an image every 220 ns and to store the acquired data in the focal plane. During the 99.4 ms time gap between two macro-bunches the data are sent off the focal plane.
