The nuclear-resonance-scattering station at the PETRA II undulator beamline

PETRA II, a 12 GeV accelerator at DESY, Hamburg, is used to produce synchrotron radiation (SR) for experiments in the hard X-ray regime when it is not running as injector for HERA. The beam from an undulator is split by a diamond crystal in Laue geometry to feed two experimental stations, one of which is now dedicated for nuclear resonance experiments. The X-ray energy may be chosen in the range from 5 to 55 keV covering all isotopes already observed with SR and many interesting candidates for new resonances. Tuning may be performed by optimising the magnetic gap and the storage ring energy. In particular, the opportunities for timing experiments are unique due to a very flexible filling mode of the storage ring. The flux at the sample position is comparable to undulator beams at ESRF. The second beamline covers higher energies up to some 300 keV and may also be used for nuclear resonance experiments. This revised version was published online in August 2006 with corrections to the Cover Date.