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 worldwide one of the 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 1.3 nmrad x 0.01 nmrad at photon energies between 150 eV and 200 keV depending on the beamline. PETRA III runs at 120 mA beam current in top-up mode in continuous mode (with 16ns bunch separation) and 100 mA in timing mode (with 192 ns bunch separation). The storage ring operations in top-up mode with 1% stability of photon flux 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. The horizontal emittance of 1.3 nm rad in both operation modes enables experiments with hight coherent X-ray flux on the sample at sub-nmicrometer focusing.

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 11 more beamlines.

In the PETRA III hall ‘Paul P. Ewald’, 4 beamlines beamlines are operated by DESY and Hereon. A 5th beamline for catalysis reseach applying XAFS, powder diffraction and SAXS measurments, is under development in close cooperation with Max-Planck Institutions. Furthermore, the beamline P66 for Time-resolved UV Luminescence is in user operation and is located outside the building in a separate experimental hutch between the ‘Paul P. Ewald' hall and the 'Max von Laue' hall.

The PETRA III experimental hall ‘Ada Yonath’ hosts 5 undulator beamlines operated by DESY, two of them in close cooperations with the CeXS, the Center for X-rays in Swedish Materials Science.

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.