View into the PETRA III ring tunnel

Components of the particle accelerator PETRA III. In the yellow undulator magnetic structures the particle bunches circulating in the PETRA III beam pipe are forced to lurch. On this lurch course the particle bunches emit the extremely bright X-ray light for experiments in the PETRA III experimental hall “Max von Laue”.

The upgrade of the PETRA II storage ring to PETRA III required the total rebuilding of one-eighth of the ring to provide the electron-beam optics for eight straight sections, each offering space for one 5 m long or two 2 m long insertion devices - so-called "undulator" magnets. 14 beamlines with independently tunable insertion devices are available. The electron energy is 6 GeV, with a beam current of 100 mA.

PETRA III offers an emittance of 1 nmrad which is a so far unrivaled value for storage rings operated at a comparable high particle energy for the production of hard X-rays.