P490 – Mirror Unit M1 MIFO PTB
Application
Mirror unit (M1) for soft X-ray synchrotron radiation
Year of delivery
2021
Installation site
MIFO beamline at National Metrology Institute (PTB) of Germany
The hexapod units for the MIFO beamline of the PTB at BESSY feature the lastest updates of the hexapod design for compact size, straightforward alignment and calibration at reliably excellent performance.
Design Features
-
Constant-strut-length hexapod mechanism.
- Six degrees of freedom and selectable rotation center.
- Spectral range: 1.5 – 10 keV.
- Optical elements: one focusing mirror.
- Active water cooling of the mirror.
- Electrode at mirror surface for carbon contamination prevention.
- Temperature sensor at internal mechanics.
- Mechanically decoupled internal mechanics from the vacuum chamber.
- Internal mechanics directly connected to the adjustable support structure underneath.
-
EtherCAT based motion control system, synchronized encoder readout (suitable for on-the-fly measurements), software with server-client architecture, TCP-IP protocol, EPICS interface.
- Adjustable support structure.
- Permanently installed bakeout provisions.
Performance Features
- High positioning resolution (minimum incremental motion).
- High stability and repeatability for all degrees of freedom.
- Minimized mounting induced deformations.
Outer Dimensions
Technical specifications and performance values
General
Vacuum chamber
Chamber type
cylindrical, vertical axis
Main flanges
at the top, flat polished, COF
Material
1.4404 (C < 0.02%)
Base pressure
10-10 mbar range
Optical design parameters
Beam height
1400 mm
Number of mirrors
1
Substrate shape
toroidal
Mirror dimensions
1000 mm x 75 mm x 80 mm
Actuator drives for hexapod axes
Resolution (design value)
0.00157 µm /motor fine step
(1/128, recommended)
0.001 µm /encoder count
Mirror mechanics
Pitch rotation
Range
± 3.1 mrad
Resolution (calculated value)
0.033 µrad
Repeatability
0.15 µrad (pitch)
0.01 µrad (roll)
Long-term stability (> 12h)
0.14 µrad
Roll rotation
Range
± 2.1°
Resolution (calculated value)
0.30 µrad
Repeatability
0.30 µrad (pitch)
0.22 µrad (roll)
Long-term stability (> 12h)
0.13 µrad
Yaw rotation
Range
± 2.1°
Resolution (calculated value)
0.036 µrad
Translation (meridional)
Range
± 3 mm
Resolution (calculated value)
10.3 nm
Repeatability
0.002 µm (translation)
Translation
along surface normal
Range
-4 mm to 6 mm
Resolution (calculated value)
11.4 nm
Translation (sagittal)
Range
-11 mm to 23 mm
Resolution (calculated value)
1.56 nm
Repeatability
0.002 µm (translation)
Performance Test Results
Pitch deviation after pitch change
Parasitic roll after pitch change
Roll deviation after roll change
Parasitic pitch after roll change
Meridional deviation after mirror translation
Sagittal deviation after mirror translation
Mirror pitch long-term stability
Mirror roll long-term stability
Residual gas analysis
