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P378 - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
P378 - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France

P378 – VLS-PGM UPBL7 ESRF

Application

Plane grating monochromator (PGM) for soft X-ray synchrotron radiation

Year of delivery

2014

Installation site

UPBL7 beamline at European Synchrotron Radiation Facility, France

This is the first monochromator built by Bestec with a liquid nitrogen cooling system, which was developed in cooperation with ESRF. At a temperature around 120 K, the expansion coefficient of silicon is close to 0. Therefore, a temperature distribution with strong variation does not lead to a significant deformation of the optical surface.

Design Features

  • High-resolution grazing incidence variable line spacing plane grating monochromator (VLS-PGM).
  • Spectral range: 300 – 2000 eV.
  • Optical elements: one plane mirror and four plane gratings.
  • Temperature sensors at internal mechanics, mirror and gratings holders.
  • Cryogenic cooling (LN2) of the plane mirror.

  • Active water cooling of the gratings.
  • Mechanically decoupled internal mechanics from the vacuum chamber.
  • Motorized precision vertical translation of the internal mechanics.

  • Adjustable support structure.
  • Permanently installed bakeout provisions.

Performance Features

  • Extremly high positioning resolution (minimum incremental motion).
  • High pitch rotation stability and repeatability.
  • Minimized mounting induced deformations.

Outer Dimensions

P378 - Outer dimensions - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France

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)

1394.5 mm

Beam offset

15 mm

Number of plane mirrors

1

Plane mirror dimensions

450 mm x 70 mm x 100 mm

Number of gratings

4

Gratings dimensions

200 mm x 40 mm x 30 mm

Support structure

Adjustment ranges

Vertical translation

± 15 mm

Motorized fine vertical translation

± 1 mm

Lateral translation

± 15 mm

Longitudinal translation

± 15 mm

Pitch

± 1°

Roll

± 1°

Yaw

± 1°

Vertical translation

Range

-1.0 mm to 2.68 mm
(wedge leveler hall side)
-0.8 mm to 2.86 mm
(wedge leveler ring side)

Resolution (design value)

0.03 µrad /motor fine step
(1/64, recommended)
0.05 µm /encoder count

Plane mirror

Pitch rotation

Range

1.32° to -8.55°

Resolution (design value)

0.0036 µrad /motor fine step
(1/64, recommended)
0.0097087 µrad /encoder count

Resolution (measured value)

0.50 µrad

Repeatability

0.40 µrad (pitch)

Long-term stability (4h)

0.01 µrad

Scanning speed

~ 680  µrad/s

Translation

Range

-7.20 mm to +54.58 mm

Resolution (design value)

0.0586 µm /motor fine step
(1/256, recommended)
0.05 µm /encoder count

Repeatability

0.30 µrad (pitch)
0.70 µrad (roll)

Gratings

Pitch rotation

Range

1.15° to -11.32°

Resolution (design value)

0.0036 µrad /motor fine step
(1/64, recommended)
0.0097087 µrad /encoder count

Resolution (measured value)

0.01 µrad

Repeatability

0.08 µrad (pitch)

Long-term stability (4h)

0.008 µrad

Scanning speed

~ 700 µrad

Translation

Range

-10.55 mm to +214.92 mm

Resolution (design value)

0.0586 µm /motor fine step
(1/256, recommended)
0.05 µm /encoder count

Repeatability

0.13 µrad (pitch)
0.17 µrad (roll)

Performance Test Results

Pitch deviation after pitch change (mirror)
P378 - Pitch deviation after pitch change (mirror) - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Pitch deviation after pitch change (grating)
P378 - Pitch deviation after pitch change (grating) - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Pitch deviation after mirror translation
P378 - Pitch deviation after mirror translation - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Roll deviation after mirror translation
P378 - Roll deviation after mirror translation - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Pitch deviation after grating translation
P378 - Pitch deviation after grating translation - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Roll deviation after grating translation
P378 - Roll deviation after grating translation - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Mirror pitch positioning resolution
P378 - Mirror pitch positioning resolution - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch positioning resolution
P378 - Grating pitch positioning resolution - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch positioning resolution
P378 - Grating pitch steps - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch positioning resolution
P378 - Grating pitch 10 nrad steps - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch positioning resolution
(with/without cooling water)
P378 - Grating pitch positioning resolution with cooling water - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch deviation during stabilisation for different cooling water flow rates
P378 - Grating pitch positioning resolution with cooling water - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Mirror pitch long-term stability
P378 - Mirror pitch long-term stability - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch long-term stability
P378 - Grating pitch long-term stability - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Mirror pitch scanning speed
P378 - Mirror pitch scanning speed - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Grating pitch scanning speed
P378 - Grating pitch scanning speed - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France
Residual gas analysis
P378 - Residual gas analysis - Plane grating monochromator (PGM) for soft X-ray synchrotron radiation, UPBL7 beamline at European Synchrotron Radiation Facility, France