Optics Hutch

Schematic view of the optics hutch of sector 7 (fully equipped).

Foreseen lens changer in the optics hutch of P10.

The Optics Hutch (OH) is situated 33-46 m from the middle of the straight section.  There is still some space available at the beginning of the optics hutch, which is reserved for a high heat load flat mirror to enable pink beam operation of the beamline.  The standard PETRA III high heat load monochromator is the next major component.  It is located at ~38 m and cooled by liquid nitrogen.  Currently it is equipped with an independent Si(111) crystal pair (3.7-30.0keV) and a Si(111) channelcut (5.0-17.0keV).  The channelcut design offers a much higher angular stability of the beam at the price of reduced energy ranges and energy dependent exit offsets.

Next is a pair of flat (R > 100km) horizontally reflecting mirrors.  The mirrors are coated with a Rhodium and a Platinum stripe to match the cutoff energy for higher energies to the experimental conditions.  The mirrors are followed by the bremsstrahlung shield (often termed beamstop) in the optics hutch.  Basically, the beamstop is a water-cooled Densimet collimator with holes for the pink beam (4mm diameter) and the monochromatic beam (4x11mm2).  Both beams need to be offset from the white beam position by a minimum of 20mm.  A girder with several optical elements has been installed after the beamstop.  Finally, it is planned to install a vertical focusing system at the end of the optics hutch to match the vertical and horizontal transverse coherence length at the experiment.

Site note: Currently the lowest reachable energy (~3.8keV) of the beamline is given by the minimum gap of the undulator of 9.8mm.

A lens changer is foreseen for the optics hutch of sector 7. The lens changer will be equipped with vertical focusing (1D) Beryllium lenses. A total of 6 different lens stacks will allow to match the horizontal and vertical transverse coherence length at a 2nd lens changer in the experimental hutch. This focusing scheme maximizes the available coherent flux for the experiment.

The 6 stacks will be equipped with the following lenses:
1) 8x 0.5mm
2) 4x 0.5mm
3) 2x 0.5mm
4) 1x 0.5mm
5) 2x 1.5mm
6) 1x 1.5mm