P438 – Mirror Unit SIX NSLS-II
Application
Mirror unit (M4) for soft X-ray synchrotron radiation
Year of delivery
2016
Installation site
SIX beamline at the synchrotron radiation source NSLS-II, USA
This soft X-ray deflecting mirror unit is part of the SIX beamline, dedicated to high resolution soft X-ray scattering experiments. Energy resolution and pointing stability are here of crucial importance. It features an adapted constant-strut-length mechanism accounting for space constraints due to the proximity to the experimental station of the resonant innelastic X-ray scattering spectrometer (RIXS).
Design Features
-
Constant-strut-length hexapod mechanism.
- Six degrees of freedom and selectable rotation center.
- Spectral range: 150 – 2000 eV.
- Optical elements: one focusing mirror.
- Electrode at mirror surface.
- Temperature sensors at mirror holder and chin guard.
-
Four motorized and electrically isolated OFHC baffle 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
1419.25 mm
Number of mirrors
1
Surface shape
ellipsoidal
Mirror dimensions
280 mm x 45 mm x 50 mm
Actuator drives for hexapod axes
Resolution (design value)
0.003 µm /motor fine step
(1/32, recommended)
0.005 µm /encoder count
Mirror mechanics
Pitch rotation
Range
± 5 mrad
Resolution (measured value)
0.05 µrad
Repeatability
0.14 µrad (pitch)
0.16 µrad (roll)
Long-term stability (> 3o minutes)
0.13 µrad
Roll rotation
Range
± 35 mrad
Resolution (measured value)
0.25 µrad
Repeatability
0.30 µrad (pitch)
0.20 µrad (roll)
Lang-term stability (> 30 minutes)
0.08 µrad
Yaw rotation
Range
± 10 mrad
Long-term stability (> 30 minutes)
0.09 µrad
Lateral translation
Range
± 5 mm
Repeatability
0.32 µrad (pitch)
0.33 µrad (roll)
Long-term stability (> 30 minutes)
0.002 µm
Longitudinal translation
Range
± 5 mm
Long-term stability (> 30 minutes)
0.008 µm
Vertical translation
Range
± 5 mm
Long-term stability (> 30 minutes)
0.007 µm
Baffle slits
Material
OFHC
Range
± 15 mm
Resolution (design value)
0.10 µm /motor step
(full step at actuator)
0.05 µm /encoder count
Performance Test Results
Pitch deviation after pitch change
Roll deviation after pitch change
Pitch deviation after roll change
Roll deviation after roll change
Pitch deviation after mirror translation
Roll deviation after mirror translation
Mirror pitch long-term stability
Mirror roll long-term stability
Mirror yaw long-term stability
Mirror lateral position long-term stability
Mirror longitudinal position long-term stability
Mirror vertical position long-term stability
Mirror pitch positioning resolution
Mirror roll positioning resolution
Residual gas analysis
