P511 – Mirror Unit M1 ELISA BESSY HZB
Application
Mirror unit (M1) for soft X-ray synchrotron radiation
Year of delivery
2024
Installation site
ELISA beamline at BESSY II, Helmholtz-Zentrum Berlin, Germany
Design Features
-
Constant-strut-length hexapod mechanism.
- Six degrees of freedom and selectable rotation center.
- Spectral range: 50 – 3000 eV.
- Optical elements: one collimating mirror.
-
Actively water cooled cooper absorbers at both long sides of the mirror.
- Electrode at mirror surface for carbon contamination prevention.
- Temperature sensors at internal mechanics and at the mirror.
-
Four motorized, encoded and water cooled OFHC blades at the chamber entrance flange; fluorescence coating of all blades.
- Mechanically decoupled internal mechanics from the vacuum chamber.
- Internal mechanics directly connected to the adjustable support structure underneath.
- Adjustable support structure.
- Permanently installed bakeout provisions.
Performance Features
- High step resolution.
- High pitch rotation stability and repeatability.
- Minimized mounting induced deformations.
Outer Dimensions
Technical specifications and performance values
General
Vacuum chamber
Chamber type
cylindrical, vertical axis
Main flanges
at the top
Material
1.4404 (C < 0.02%)
Base pressure
10-10 mbar range
Optical design parameters
Beam height
1400 mm
Number of mirrors
1
Surface shape
toroidal
Mirror dimensions
1000 mm x 100 mm x 80 mm
Actuator drives for hexapod axes
Resolution (design value)
0.00157 µm /motor fine step
(1/128, recommended)
0.005 µm /encoder count
Mirror mechanics
Pitch rotation
Range
± 18 mrad
Resolution (calculated value)
0.103 µrad
Resolution (measured value)
0.10 µrad
Repeatability
< 0.50 µrad
Roll rotation
Range
± 10 mrad
Resolution (calculated value)
1.55 µrad
Resolution (measured value)
0.10 µrad
Repeatability
< 0.50 µrad
Yaw rotation
Range
± 10 mrad
Resolution (calculated value)
0.115 µrad
Vertical translation
Range
± 12 mm
Resolution (calculated value)
5 nm
Translation
along surface normal
Range
± 12 mm
Resolution (calculated value)
39.7 nm /step
Resolution (measured value)
1 µm
Repeatability upon translation
0.50 µm
Translation along surface
Range
± 12 mm
Resolution (calculated value)
34 nm
Aperture unit
Blades
Material
OFHC
Translation range / blade
30 mm
Resolution (design value)
0.00157 µm /motor fine step
(1/64, recommended)
0.05 µm /encoder count
Resolution (measured value)
0.50 µm
Repeatability
< 1 µm
Performance Test Results
Pitch deviation after pitch change
Roll deviation after pitch change
Pitch deviation after pitch change
Roll deviation after pitch change
Pitch deviation after pitch change
Roll deviation after pitch change
Pitch deviation after roll change
Roll deviation after roll change
Pitch deviation after roll change
Roll deviation after roll change
Pitch deviation after roll change
Roll deviation after roll change
Mirror pitch positioning resolution
Mirror roll positioning resolution
Position deviation after mirror transversal translation
Mirror transversal translation positioning resolution
Blade position deviation after blade translation
Blade translation positioning resolution
Residual gas analysis
