P412 – Mirror Unit PINK EMIL BESSY
Application
Mirror unit (M2) for hard X-ray synchrotron radiation
Year of delivery
2016
Installation site
EMIL hard X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany
This hard X-ray switching mirror unit is part of the combined hard and soft X-ray EMIL beamlines at BESSY. It features an optimized design of the constant-strut-length hexapod mechanism used for the first Bestec hexapod (see project P377). The mirror switching is realized by a vertical movement. The vacuum chamber accomodates not only the actual beam but also the passing soft X-ray beams of the neighbouring branches.
Design Features
-
Constant-strut-length hexapod mechanism.
- Six degrees of freedom and selectable rotation center.
- Spectral range: 3 – 9.5 keV.
- Optical elements: three focusing mirrors.
-
Active side water cooling of all mirrors.
- Electrode at mirrors surfaces for carbon contamination prevention.
- Temperature sensors at mirrors chin guards.
- Four water cooled, motorized OFHC aperture blades at the entrance flange.
- Permanently installed bakeout provisions.
- Adjustable support structure.
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
Material
1.4404 (C < 0.02%)
Base pressure
10-10 mbar range
Optical design parameters
Beam height
1400 mm / 1420 mm
Number of mirrors
3
Surface shape
cylindrical
Mirror dimensions
120 x 46(26) x 40(8) mm3
(T-Profile)
Actuator drives for hexapod axes
Resolution (design value)
0.004 µm /motor fine step
(1/128, recommended)
0.005 µm /encoder count
Mirror mechanics
Pitch rotation
Range
± 8 mrad
Resolution (measured value)
0.05 µrad
Repeatability
0.09 µrad (pitch)
0.06 µrad (roll)
Long-term stability (30 minutes)
0.05 µrad
Roll rotation
Range
± 20 mrad
Resolution
0.05 µrad
Repeatability
0.07 µrad (pitch)
0.06 µrad (roll)
Yaw rotation
Range
± 8 mrad
Resolution
0.05 µrad
Vertical translation (switch)
Range
± 60 mm
Horizotal translation
Range
± 5 mm
Aperture unit
Blades
Material
OFHC (water cooled)
Stroke
50 mm
Resolution
15 µm /motor step
(full step at actuator)
4.125 µm /motor step
(full step at blade)
Performance Test Results
Pitch deviation after pitch change
Roll deviation after pitch change
Pitch deviation after roll change
Roll deviation after roll change
Mirror pitch positioning resolution
Mirror pitch long-term stability
