P428 – Mirror Unit ESM NSLS-II
Application
Mirror unit (M1) for soft X-ray synchrotron radiation
Year of delivery
2015
Installation site
ESM beamline at the synchrotron radiation source NSLS-II, USA
This mirror unit features a cardanic mount to realize the required degrees of freedom. The challenge was to accomodate all components within the lateral space constrains in the M1 hutch of the ESM beamline at NSLS-II. Special attention was payed to block zero-order and stray light by using several water cooled masks and beam stops.
Design Features
-
In-UHV stacked design for the requested degrees of freedom.
- Spectral range: 15 – 1500 eV.
- Pitch rotation stage motorized and encoded in-UHV.
- Roll rotation guidance system motorized and encoded in-UHV.
- Linear stage for mirror horizontal translation motorized and encoded in-air.
- Temperature sensors at mirror holder, chin guard, baffle slits, entrance mask, exit mask and beam stop.
- Electrode at mirror surface for carbon contamination prevention.
-
Active water cooling of the mirror.
- Water cooled beam-stop, entrance and exit masks.
- Four water cooled, motorized and electrically isolated OFHC baffle blades at the exit flange.
- Permanently installed bakeout provisions.
- Adjustable support structure.
Performance Features
- High positioning resolution (minimum incremental motion).
- High pitch rotation stability and repeatability.
- Minimized mounting induced deformations.
Outer Dimensions
Technical specifications and performance values
General
Vacuum chamber
Chamber type
stadium shaped footprint
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
plane
Mirror dimensions
605 mm x 70 mm x 60 mm
Mirror mechanics
Pitch rotation
Range
± 0.5 mrad
Resolution (design value)
0.036 µrad /motor step
0.0067 µrad /encoder count
Resolution (measured value)
0.10 µrad
Repeatability
0.16 µrad (pitch)
0.15 µrad (roll)
Long-term stability (30 minutes)
with cooling water
0.02 µrad
Roll rotation
Range
± 20 mrad
Resolution (design value)
0.068 µrad /motor step
0.0067 µrad /encoder count
Resolution (measured value)
0.25 µrad
Repeatability
0.17 µrad (pitch)
0.40 µrad (roll)
Long-term stability (30 minutes)
with cooling water
0.04 µrad
Translation
along surface normal
Range
-11.8 mm to +11.7 mm
Resolution (design value)
0.30 µm /motor step
0.05 µm /encoder count
Repeatability
1 µm
Baffle slits
Blades
Material
OFHC
Range
-2 mm to +15 mm
Resolution (design value)
0.10 µm /motor step
(full step at actuator)
Parallelism
≤ 10 µm
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 with cooling water
Mirror roll positioning resolution
Mirror roll long-term stability with cooling water
Residual gas analysis
