Computer EngineeringFastest Camera

13 August 2019

Heidelberg physicists help develop a high-performance detector to image X-rays

The world’s fastest camera for imaging individual protons in the so-called soft X-ray range has begun operations. It was developed by an international consortium which includes physicists from Heidelberg University. The so-called DSSC detector is being used at the European XFEL research facility in Hamburg. There, ultrashort X-ray flashes are generated in underground tunnels, enabling researchers to see the atomic details of viruses or to film chemical reactions, for example.


In experiments at the XFEL, ultrashort X-ray flashes are fired at the sample being studied. The X-rays diffract off the atoms in the sample, resulting in a distinctive pattern that is recorded by the detector located behind the sample. The DSSC can acquire 4.5 million images per second until the capacity of the 800 internal memory cells is reached. In the intervals between the flashes, the data are then read out via several 10Gb (gigabit) fibre-optic cables, making the DSSC the fastest soft X-ray detector in the world, i.e., for long wavelengths with low energies.

The Heidelberg scientists under the direction of Prof. Dr Peter Fischer at the Institute of Computer Engineering (ZITI) designed major electronic circuits for the main read-out chip, coordinated its overall development, contributed the complex electronic printed circuit board for data read-out, and programmed the so-called FPGA chips that can receive, temporarily store, re-sort, and forward the data at high speed. “We also developed the software for readout and analysis of the large volumes of data and helped in commissioning the finished camera”, explains Prof. Fischer, whose research group has been working on the project for over ten years. “DSSC is an extremely good example for how new scientific knowledge can often only be gained using totally innovative devices whose development demands a great deal of experience, technological know-how, and time. Even in Formula 1, winning requires not only a good driver but especially a top-notch race car”, adds Peter Fischer.

In addition to the Heidelberg researchers, other members of the international consortium that developed the DSSC detector include experts from the German Electron Synchotron (DESY) and European XFEL research centres as well as the University of Bergamo and the Polytechnic University of Milan (Italy). The silicon sensors used were designed and produced at the Semiconductor Laboratory of the Max-Planck-Society in Munich.

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