P373 – VLS-PGM BL5 SSRL
Application
Large angle plane grating monochromator (PGM) for soft X-ray synchrotron radiation
Year of delivery
2013
Installation site
BL5 beamline at synchrotron radiation source SSRL, USA
Design Features
-
High-resolution large-angle grazing incidence variable line spacing plane grating monochromator (VLS-PGM).
- Spectral range: 25 – 200 eV.
- Optical elements: one plane mirror and three VLS plane gratings.
- Temperature sensors at internal mechanics, at mirror and gratings chin guards, at mirror and grating substrates.
-
Active water cooling of the mirror, passive cooling of the gratings.
- Four indirectly cooled OFHC aperture blades at the PGM exit flange; motorized and encoded independent translation of the vertically defining blades.
-
Water cooled zero-order stop.
-
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)
1071 mm
Beam offset
25 mm
Number of plane mirrors
1
Plane mirror dimensions
280 mm x 50 mm x 50 mm
Number of gratings
1
Gratings dimensions
60 mm x 30 mm x 23 mm
100 mm x 30 mm x 23 mm
150 mm x 30 mm x 23 mm
Support structure
Adjustment ranges
Vertical translation
± 10 mm
Lateral translation
± 10 mm
Longitudinal translation
± 10 mm
Pitch
± 1°
Roll
± 1°
Yaw
± 1°
Plane mirror
Pitch rotation
Range
-1.17° to +27.35°
Resolution (design value)
0.004 µrad /motor fine step
(1/64, recommended)
0.0097087 µrad /encoder count
Resolution (measured value)
0.10 µrad
Repeatability
0.21 µrad (pitch)
0.18 µrad (roll)
Long-term stability (>10h)
0.03 µrad
Stability (2 l /min cooling water)
<0.05 µrad
Translation
Range
55 mm
Resolution (design value)
0.03 µm /motor fine step
(1/512, recommended)
0.05 µm /encoder count
Repeatability
0.20 µrad (pitch)
0.18 µrad (roll)
Gratings
Pitch rotation
Range
-1.16° to +31.32°
Resolution (design value)
0.004 µrad /motor fine step
(1/64, recommended)
0.0097087 µrad /encoder count
Resolution (measured value)
0.10 µrad
Repeatability
0.15 µrad (pitch)
0.25 µrad (roll)
Long-term stability (>2h)
0.04 µrad
Stability (2 l /min cooling water)
< 0.065 µrad
Translation
Range
159.15 mm
Resolution (design value)
0.02 µm /motor fine step
(1/512, recommended)
0.05 µm /encoder count
Repeatability
0.13 µrad (pitch)
0.24 µrad (roll)
Aperture unit
Blades
Material
OFHC
Range
-5 mm to + 10 mm
Resolution (design value)
10 µm /step (full step)
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 positioning resolution (2 l /min)
Grating pitch positioning resolution
Grating pitch positioning resolution (2 l /min)
Mirror pitch positioning resolution
Grating pitch positioning resolution
Mirror pitch long-term stability
Grating pitch long-term stability
Residual gas analysis
