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P489 – RIXS Monochromator SSRF
Application
Spherical grating monochromator (SGM) for soft X-ray synchrotron radiation
Year of delivery
2022
Installation site
Dreamline beamline at synchrotron radiation source SSRF, China
Design Features
- Grating unit for high resolution soft X-ray spectrometer.
- Spectral range: 250 – 1700 eV.
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Very compact design for integration into the RIXS system.
- Very short vertical distance between bottom interface plate and grating axis.
- Optical elements: three spherical gratings.
- Temperature sensors at internal mechanics and gratings’ chin guards.
- Motorized and encoded vertical translation of the internal mechanics for compensation of spurious height and roll variation upon scattering angle change.
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Motion control system with EPICS interface, EtherCAT, fast encoder readout suitable for on-the-fly measurements.
- Mechanically decoupled internal mechanics from the vacuum chamber.
- Internal mechanics directly connected to the adjustable support structure underneath.
- Permanently installed bakeout provisions.
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
rectangular footprint
Main flanges
at the top
Material
1.4404 (C < 0.02%)
Base pressure
10-10 mbar range
Optical design parameters
Beam height (entrance)
1320 mm
Number of gratings
3
Gratings dimensions
180 mm x 50 mm x 50 mm
Grating mechanics
Pitch rotation
Range
-8.30° to +1.06°
Resolution (design value)
0.0048 µrad /motor fine step
(1/128, recommended)
0.00146 µrad /encoder count
Resolution (measured value)
0.05 µrad
Abolute accuracy
0.50 µrad
Repeatability
0.20 µrad (pitch)
0.17 µrad (roll)
Long-term stability (> 1h)
0.037 µrad
Translation (grating exchange)
Range
-90.05 mm to +90.04 mm
Resolution (design value)
0.078 µm /motor fine step
(1/128, recommended)
0.05 µm /encoder count
Resolution (measured value)
5 µm
Repeatability
0.14 µrad (pitch)
0.12 µrad (roll)
Translation (grating height)
Range
-3.37 mm to +3.39 mm
(wedge leveler 1)
-3.35 mm to +3.36 mm
(wedge leveler 2)
Resolution (design value)
0.20 µm /motor step (at actuator)
0.02 µm /motor step
(at wedge leveler)
0.05 µm /encoder count
Resolution (measured value)
0.20 µm
Long-term stability (ca. 1h)
0.01 µm