Beamline Layout

Schematic layout of beamline P22

The photon source is a 2m long spectroscopy undulator U33 in a high-β section which is shared with beamline P23 in a canted undulator scheme. For HAXPES applications, it covers an energy range between 2.4 and 30 keV. All frontend components such as high power slit systems, monitors etc are based on the generic design developed for PETRA III and mounted on four different girders.

U33 undulator of beamline P22

Photon flux of the U33 undulator (spectral Si(111) bandpass)

Beamline front end looking downstream

The first major optical element in the optics hutch is the primary LN2-cooled double Si-crystal monochromator which comprises remotely interchangeable pairs of Si(111) and (311) crystal pairs. This is followed by a double channel-cut (4-bounce) post-monochromator (PM) for higher energy resolution requirements. in addition, the PM vacuum vessel also accommodates a stage with diamond phase plates providing variable left/right circular beam polarization.

High heatload LN2-cooled double crystal monochromator

Beam focusing is realised by horizontally deflecting mirrors, combining a cylindrical - plane mirror pair (inside the optics hutch) for the vertical with a plane elliptical bendable mirror (in the experimental hutch) located close to the experiments for the horizontal. The minimum spot size at the first instrument position is <10x10 µm2 providing about 2x1013 ph/s (Si(111) at 4-6 keV). Additionally, a 1D Be-lens transfocator can be used optionally for horizontal focusing down to about 70x10 µm2 on the sample. For a controlled attenuation of the beam intensity, a precision attenuator with remotely interchangeable high-purity metal foils is installed in the beam path.

Primary mirror systems consisting of a cylindrical mirror followed by a plane mirror. The mirrors are deflecting horizontally and have two coatings, B4C and Pd.

Lens changer for 1D Be compound refractive lenses

X-ray intensity attenuator