PETRA III - Facility Information

Brilliant light for DESY users

Aerial view of the three PETRA III experimental halls ‘Ada Yonath’ (left), ‘Max von Laue’ (curved building in the middle) and ‘Paul P. Ewald’ (right, adjacent to the two FLASH halls) in September 2016.

One of the two damping wiggler sections in the PETRA III storage ring

One of the two damping wiggler sections in the PETRA III storage ring.

Figure 4

A view into the ring tunnel within the PETRA III experimental hall, showing a machine girder that carries quadrupole magnets (left). The undulator of this straight section will be mounted in the foreground. Behind it (right part of the picture) some the of granite girders for the beamline frontend components are seen.

PETRA III is the worldwide most brilliant storage ring based X-ray sources for high energy photons providing a brilliance exceeding 1021 ph/(s mm2 mrad2 0.1% BW). It operates at 6 GeV particle energy and provides a horizontal and vertical emittance of 1.2 nmrad x 0.01 nmrad at photon energies between 150 eV and 200 keV depending on the beamline. PETRA III runs at 100 mA beam current in top-up mode keeping the photon flux stable with 1% and provides 5000 h X-ray beam per year for user operation. The vertical beam parameters of PETRA III are close to the diffraction limit and hence are very similar to other high-energy 3rd generation sources. However, today the horizontal emittance of 1.2 nm rad is 3 – 4 times smaller at PETRA III compared to any other high-energy (6 GeV and higher) storage ring in the world, which makes PETRA III a unique synchrotron light source.

The beamlines at PETRA III are distributed over three experimental halls. The largest, 300 m long experimental hall ‘Max von Laue’ covers one octant of the 2304 m long PETRA storage ring on the DESY site. On the 7000 m2 large experimental floor 15 beamlines are operated by DESY, Helmholtz-Zentrum Hereon (formerly HZG), and the European Molecular Biology Laboratory (EMBL) with more than 30 experimental stations which have been optimized for the use of the high brilliance of the PETRA III beam. All beamlines in the PETRA III experimental hall ‘Max von Laue’ are fully operational and open for user proposals since 2013. Some beamlines have even been upgraded since then with additional undulators, optics, experimental setups and/or detectors.

In 2016, two additional experimental halls have been inaugurated: the ‘Paul P. Ewald’ and the ‘Ada Yonath’ halls, located on the northern and eastern side of the experimental hall ‘Max von Laue’. These new halls offer space for 10 more beamlines.

In the PETRA III hall ‘Paul P. Ewald’, two beamlines for X-ray absorption spectroscopy are in user operation, P65 (Applied XAFS) and P64 (Advanced XAFS) for high-flux applications. The high-flux, high-energy wiggler beamline P61 for extreme conditions and engineering materials science research is under construction. It is shared between DESY and Hereon. The large volume press instrument downstream at P61 is already being used in off-line mode for materials synthesis. The beamline is expected to receive first beam in spring 2019. The detailed planning and initial construction of the Anomalous Small Angle Scattering beamline P62 has started. The beamline will be operational in 2020. Construction of the Time-resolved UV Luminescence beamline P66, which is located in a separate experimental hutch outside the P.P. Ewald hall, is also under way.

The PETRA III experimental hall ‘Ada Yonath’ hosts four undulator beamlines. The Chemical Crystallography beamline P24 is in user operation since spring 2018. Beamlines P22 for hard X-ray photoelectron spectroscopy techniques and P23 for in-situ and nano-diffraction will be starting full user operation in September 2018. The Swedish High-energy X-ray Materials Science beamline P21 will receive first beam in September 2018 and start commissioning. Operation for users will begin in 2019.

Due to its preeminant circumference the PETRA III storage ring can host a large number of bending magnets and is therefore ideally suited to be upgraded into a source for ultralow emittance applications: PETRA IV. By employing modern techniques for storage rings (‘multi-bend-achromat technology’) a factor of 50 to 100 better brilliance can be achieved. PETRA IV would be capable of providing beams of hard X-rays with unprecedented coherence properties that can be focused to dimensions in the nanometer-regime enabling groundbreaking studies in a multitude of disciplines.