Ever since the particle accelerator HERA came to its scheduled end at DESY, the pre-accelerator PETRA has been available again for other tasks and assignments. To this end, the facility has been completely re-equipped to become the world’s brightest storage ring X-ray source.

So, it ideally complements the experimental options and choices at the European X-ray Laser XFEL, which is still being built. To refit PETRA, the 2.3 kilometre long storage ring was completely modernised and a new experiment hall equipped with 30 measuring stations was built over 300 metres in length. “This involved the world’s longest, continuous concrete slab being poured beneath the hall to guarantee the very best conditions for the experiments,” says Dr. Hermann Franz, who coordinated the redevelopment project.

PETRA III delivers X-rays of a particular high brilliance. Very many photons are precision packaged to create a highly intensive light beam. This means that the atomic structure of extremely small material probes can also be examined. That is important for biologists who study complex molecules that do not form larger crystals. With the new light source, the biologists can already explain on the basis of tiny protein crystals how atoms arrange themselves spatially. And so they can, for example, develop new drugs that are applied exactly where pathogens attack. The brilliant X-ray source also opens up new opportunities for materials scientists.

Particularly energy rich photons with a strong penetration capacity are needed to examine welding seams or to study material fatigue on tools. The PETRA storage ring can generate radiation of up to 100 kilo electron volts with a high brightness and hence is a lamp that provides a greater insight. “Now that all the dry runs have been successfully completed, the colleagues are looking forward expectantlyto the first real experiments in order to throw an even sharper insight into the nanocosm,” says Franz.