P513 – PGM FEL-II SHINE
Application
Plane grating monochromator (PGM) for soft X-ray radiation
Year of delivery
to be delivered 2025
Installation site
FEL-II beamline at SHINE, Shanghai, China
The relatively long optical elements required a customized design for the internal mechanics to achieve ultimate stability and repeatability. The stadium-shaped footprint of the vacuum chamber, which accommodate the longer optics, allows for reduced mass and higher eigenfrequencies compared to a rectangular chamber. Mounting-induced deformation of the optical components is minimized by implementing a bottom cooling system.
Design Features
- Plane grating monochromator.
- Spectral range: 200 – 2000 eV.
- Optical elements: one plane mirror and three plane gratings.
-
Electrode at mirror surface for carbon contamination prevention.
- Temperature sensors at internal mechanics, mirror and gratings .
-
Active water bottom cooling of all optical elements.
- EtherCAT based motion control system, synchronized encoder readout, software with server-client architecture, TCP-IP protocol, EPICS interface.
- Mechanically decoupled internal mechanics from the vacuum chamber.
- Internal mechanics directly connected to the adjustable support structure underneath.
- Adjustable support structure.
- Permanently installed bakeout provisions.
Performance Features
- High positioning resolution.
- 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 (entrance)
1300 mm
Beam offset
20 mm
Number of plane mirrors
1
Plane mirror dimensions
800 mm x 50 mm
Number of gratings
3
Gratings dimensions
320 mm x 30 mm
Support structure
Adjustment ranges
Vertical translation
± 10 mm
Horizontal translation
± 10 mm
Pitch
± 1.5°
Roll
± 1.5°
Yaw
± 1.5°
Plane mirror
Pitch rotation
Range
-0.50° to +5.30°
Resolution (design value)
0.00263 µrad /motor fine step
(1/128, recommended)
0.001463 µrad /encoder count
Resolution (measured value)
0.05 µrad
Repeatability
0.11 µrad (pitch)
0.10 µrad (roll)
Long-term stability (> 1.5 h)
0.062 µrad
Long-term stability (> 30 min)
1.25 l/min water flow rate
0.072 µrad
Long-term stability (5 h)
1.25 l/min water flow rate
0.043 µrad
(measured with low noise incremental encoder)
Translation
Range
-41.80 mm to +35.80 mm
Resolution (design value)
0.0129 µm /motor fine step
(1/64, recommended)
0.05 µm /encoder count
Repeatability
0.11µrad (pitch)
0.12 µrad (roll)
Gratings
Pitch rotation
Range
-0.65° to +7.10°
Resolution (design value)
0.00263 µrad /motor fine step
(1/128, recommended)
0.001463 µrad /encoder count
Resolution (measured value)
0.05 µrad
Repeatability
0.08 µrad (pitch)
0.03 µrad (roll)
Long-term stability (> 1.5 h)
0.035 µrad
Long-term stability (30 min)
1.25 l/min water flow rate
0.036 µrad
Translation
Range
-85.20 mm to +85.30 mm
Resolution (design value)
0.0129 µm /motor fine step
(1/64, recommended)
0.05 µm /encoder count
Repeatability
0.08 µrad (pitch)
0.11 µrad (roll)
Performance Test Results
Pitch deviation after pitch change (mirror)
Roll deviation after pitch change (mirror)
Pitch deviation after pitch change (grating)
Roll deviation after pitch change (grating)
Pitch deviation after mirror translation
Roll deviation after mirror translation
Pitch deviation after grating translation
Roll deviation after grating translation
Mirror pitch positioning resolution
Mirror pitch step width
Grating pitch positioning resolution
Grating pitch step width
Mirror pitch long-term stability
Grating pitch long-term stability
Mirror pitch long-term stability
(1.25 l/min water flow rate)
Grating pitch long-term stability
(1.25 l/min water flow rate)
Mirror pitch long-term stability
(1.25 l/min water flow rate)
Residual gas analysis
