P308 – VLS-PGM SXR LCLS SLAC
Application
Plane grating monochromator (PGM) for soft X-ray FEL radiation
Year of delivery
2010
Installation site
Soft X-ray beamline at LCLS, Stanford Linear accelerator Center, USA
This monochromator was the first soft X-ray monochomator delivered to the world’s first X-ray free-electron laser at LCLS at SLAC.
Design Features
-
High-resolution extremely grazing incidence variable line spacing plane grating monochromator (VLS-PGM).
-
XFEL compatible, optimized for very short pulses.
- Spectral range: 500 – 2000 eV.
- Optical elements: one spherical mirror and two VLS plane gratings.
- Four motorized and encoded B4C aperture blades at the entrance flange.
- Adjustable support structure.
Performance Features
- High pitch rotation stability and repeatability.
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)
1340 mm
Beam offset
8 mm
Number mirrors
1 (spherical)
Mirror dimensions
300 mm x 110 mm x 75 mm
Number of gratings
2
Gratings dimensions
220 mm x 50 mm x 23 mm
Support structure
Adjustment ranges
Vertical translation
± 12.5 mm
Transversal translation
± 12.5 mm
Longitudinal translation
± 12.5 mm
Pitch
± 1°
Roll
± 1°
Yaw
± 2°
Spherical mirror
Pitch rotation
Range
0.6° to 1°
Resolution (design value)
0.015 µrad /motor fine step
(1/16, recommended)
0.0484814 µrad /encoder count
Repeatability
0.20 µrad (pitch)
Gratings
Pitch rotation
Range
0.05° to +0.9°
Resolution (design value)
0.015 µrad /motor fine step
(1/16, recommended)
0.0484814 µrad /encoder count
Repeatability
0.19 µrad (pitch)
Translation
Range
100 mm
Resolution (design value)
0.03 µm /motor fine step
(1/512, recomended)
0.05 µm /encoder count
Repeatability
0.19 µrad (pitch)
Aperture unit
Blades
Material
B4C
Range
± 2.5 mm
Resolution
0.04 µm /motor fine step
(1/128, recommended)
0.05 µm /encoder count
Performance Test Results
Pitch repeatability after pitch change (mirror)
Pitch repeatability after pitch change (grating)
Pitch repeatability after grating translation
