P355 – VLS-PGM Dreamline SSRF
Application
Plane grating monochromator (PGM) for soft X-ray synchrotron radiation
Year of delivery
2012
Installation site
Dreamline beamline at synchrotron radiation source SSRF, China
Design Features
-
High-resolution grazing incidence variable line spacing plane grating monochromator (VLS-PGM).
- Spectral range: 20 – 2000 eV.
- Optical elements: one plane mirror and four VLS plane gratings.
-
Gold coated and isolated chin guards at all optical elements.
- Temperature sensors at mirror/gratings holders and at mirror/gratings substrates.
-
Active water cooling of all optical elements.
-
Motion control system with EPICS interface.
- 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
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 (entrance)
1280 mm
Beam offset
20 mm
Number of plane mirrors
1
Plane mirror dimensions
410 mm x 50 mm x 60 mm
Number of gratings
4
Gratings dimensions
120 mm x 40 mm x 50 mm
Support structure
Adjustment ranges
Vertical translation
± 15 mm
Lateral translation
± 15 mm
Longitudinal translation
± 15 mm
Pitch
± 1.5°
Roll
± 1.5°
Yaw
± 1.5°
Plane mirror
Pitch rotation
Range
-0.74° to +12.75°
Resolution (design value)
0.00375 µrad /motor fine step
(1/64, recommended)
0.0097087 µrad /encoder count
Resolution (measured value)
0.50 µrad
Repeatability
0.17 µrad (pitch)
0.10 µrad (roll)
Stability
0.04 µrad
Translation
Range
-22 mm to +17.75 mm
Resolution (design value)
0.03 µrad /motor fine step
(1/512, recommended)
0.05 µm /encoder count
Repeatability
0.16 µrad (pitch)
0.35 µrad (roll)
Gratings
Pitch rotation
Range
-2° to +16.7°
Resolution (design value)
0.00375 µrad /motor fine step
(1/64, recommended)
0.0097087 µrad /encoder count
Resolution (measured value)
0.50 µrad
Repeatability
0.20 µrad (pitch)
0.48 µrad (roll)
Stability
0.02 µrad
Stability (1.5 l /min cooling water)
0.05 µrad
Translation
Range
-8 mm to +181.3 mm
Resolution (design value)
0.03 µrad /motor fine step
(1/512, recommended)
0.05 µm /encoder count
Repeatability
0.12 µrad (pitch)
0.20 µrad (roll)
Performance Test Results
Pitch deviation after pitch change (mirror)
Roll deviation after pitch change (mirror)
Pitch deviation after mirror translation
Roll deviation after mirror translation
Pitch deviation after pitch change (grating)
Roll deviation after pitch change (grating)
Pitch deviation after grating translation
Roll deviation after grating translation
Grating pitch positioning resolution
Grating pitch positioning resolution (1.5 l /min)
Grating pitch deviation (with/without cooling water)
Mirror pitch positioning resolution
