![P392 - Monochromator - Bestec GmbH_02 P392 - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation at ESM beamline at synchrotron radiation source NSLS-II, USA - Bestec GmbH](https://bestec-berlin.de/wp-content/uploads/2015/05/P392-Monochromator-Bestec-GmbH_02-853x1024.png)
P392 – VLS-PGM ESM NSLS-II
Application
Plane grating monochromator (PGM) for soft X-ray synchrotron radiation
Year of delivery
2015
Installation site
ESM beamline at synchrotron radiation source NSLS-II, USA
The long pre-mirror integrated in this monochromator required an adapted design to achieve the requested high repeatability and stability of mirror and grating pitch rotations. Special attention was payed to block zero-order and stray light by using several water cooled masks and beam stops.
Design Features
-
High-resolution grazing incidence variable line spacing plane grating monochromator (VLS-PGM).
- Spectral range: 15 – 1500 eV.
- Optical elements: one plane mirror and four VLS plane gratings.
- Temperature sensors at internal mechanics, mirror and gratings chin guards and mirror body.
-
Active water cooling of all optical elements.
-
Two piezo actuators at the sine-bar rotation mechanisms.
- Four water cooled, motorized and electrically isolated OFHC baffle blades at the exit flange.
-
Water cooled entrance and external zero-order masks and beam stop.
- 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)
1400 mm
Beam offset
40 mm
Number of plane mirrors
1
Plane mirror dimensions
585 mm x 60 mm x 70 mm
Number of gratings
4
Gratings dimensions
190 mm x 40 mm x 40 mm
Support structure
Adjustment ranges
Vertical translation
± 15 mm
Lateral translation
± 15 mm
Longitudinal translation
± 15 mm
Pitch
± 1°
Roll
± 1°
Yaw
± 1°
Mirror mechanics
Pitch rotation
Range
+0.35° to -20.3°
Resolution (design value)
0.0037 µrad /motor fine step
(1/64, recommended)
0.0047961 µrad /count
Repeatability
0.09 µrad (pitch)
0.13 µrad (roll)
Scanning speed
~750 µrad /s
Grating mechanics
Pitch rotation
Range
+0.6° to -26°
Resolution (design value)
0.0037 µrad /motor fine step
(1/64, recommended)
0.0047961 µrad /count
Resolution (measured value)
0.05 µrad
Repeatability
0.08 µrad (pitch)
0.06 µrad (roll)
Stability
0.010 µrad
Stability (1.4 l /min cooling water)
0.014 µrad
Scanning speed
~800 µrad /s
Translation
Range
-22 mm to +224.5 mm
Resolution (design value)
0.04 µm /motor fine step
(1/128, recommended)
0.05 µm /encoder count
Repeatability
0.12 µrad (pitch)
Aperture unit
Blades
Material
OFHC
Range
-2 mm to +15 mm
Resolution
0.10 µm /step (full step)