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P408 - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
P408 - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH

P408 – Mirror Unit SISSY_soft EMIL BESSY

Application

Mirror unit (M4) for soft X-ray synchrotron radiation

Year of delivery

2015

Installation site

EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany

This soft X-ray split mirror unit is part of the combined hard and soft X-ray EMIL beamlines at BESSY. It features an optimized design of the constant-strut-length hexapod mechanism used for the first Bestec hexapod  (see project P377). The mirror splitting is realized by a vertical movement. The vacuum chamber accomodates not only the actual beam but also the passing hard X-ray beam of the neighbouring branch.

Design Features

  • Constant-strut-length hexapod mechanism.

  • Six degrees of freedom and selectable rotation center.
  • Spectral range: 80 – 2000 eV.
  • Optical elements: two focusing mirrors.
  • Electrodes at mirrors surfaces for carbon contamination prevention.
  • Provisions for RF oxygen plasma cleaning of the optical surfaces.

  • Provisions for measuring the photocurrent at each mirror.
  • Beam diagnostic unit at the exit flange.
  • Permanently installed bakeout provisions.
  • Adjustable support structure.

Performance Features

  • High positioning resolution (minimum incremental motion).
  • High stability and repeatability for all degrees of freedom.
  • Minimized mounting induced deformations.

Outer Dimensions

P408 - Outer dimensions - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH

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

1420 mm

Number of mirrors

2 (3 mirror slots)

Surface shape

ellipsoidal

Mirror dimensions

420 x 50(40) x 40(5) mm3

Actuator drives for hexapod axes

Resolution (design value)

0.004 µm /motor fine step
(1/128, recommended)
0.005 µm /encoder count

Mirror mechanics

Pitch rotation

Range

± 8 mrad

Resolution (measured value)

0.05 µrad

Repeatability

0.13 µrad (pitch)

0.20 µrad (roll)

Long-term stability (1h)

0.05 µrad

Roll rotation

Range

± 10 mrad

Resolution

0.05 µrad

Repeatability

0.08 µrad (pitch)

0.30 µrad (roll)

Long-term stability (1h)

0.04 µrad

Yaw rotation

Range

± 8 mrad

Resolution

0.05 µrad

Long-term stability (1h)

0.04 µrad

Vertical translation (switch)

Range

± 75 mm

Horizontal translation

Range

± 5 mm

Aperture unit

Blades (manual)

Material

OFHC

Stroke

25 mm, 50 mm

Spindle pitch

1 mm

Performance Test Results

Pitch deviation after pitch change
P408 - Pitch deviation after pitch change - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Roll deviation after pitch change
P408 - Roll deviation after pitch change - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Pitch deviation after roll change
P408 - Pitch deviation after roll change - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Roll deviation after roll change
P408 - Roll deviation after roll change - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Mirror pitch positioning resolution
P408 - Mirror pitch positioning - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Mirror pitch long-term stability
P408 - Mirror pitch stability - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Mirror roll long-term stability
P408 - Mirror roll stability - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Mirror yaw long-term stability
P408 - Mirror yaw stability - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH
Residual gas analysis
P408 - Residual gas analysis - Mirror unit (M4) for soft X-ray synchrotron radiation at EMIL soft X-ray beamline at BESSY, Helmholtz-Zentrum Berlin, Germany - Bestec GmbH