P399 – Exit Slit Unit XM BESSY/HZB
Application
Exit slit unit for soft X-ray synchrotron radiation
Year of delivery
2015
Installation site
XM beamline at BESSY, Helmholtz-Zentrum Berlin, Germany
Design Features
- Double slit mechanism – vertically and horizontally defining slits.
-
Motorized and encoded slits opening, symmetric opening, non-linear opening characteristics.
- Hardened stainless steel slit blades.
-
Electrical isolation and gold coating of the horizontally defining slit blades.
- Motorized and encoded slit unit translation along beam axis.
- Motorized and encoded translation of the horizontally defining slit transversal to the beam axis.
- Manual rotation of the vertically defining slit.
- Bias plate coated with fluorescent material.
- Adjustable support structure.
Performance Features
- Precision and slit opening repeatability smaller than 100 nm.
- Parallelism smaller than 0.8 µm over 10 mm edge length.
- Straightness smaller than 0.5 µm over 10 mm edgle length.
- Very small deviation (submicrometer) of the slit opening calibration curve from the theoretical non-linear slit opening function.
Outer Dimensions
Technical specifications and performance values
General
Vacuum chamber
Chamber type
cylindrical, horizontal axis
Main flanges
DN160CF cluster flanges
Material
1.4301
Base pressure
10-10 mbar range
Translation along beam axis
Range
400 mm
Resolution (design value)
0.008 µm /motor fine step
(1/128, recommended)
0.01 µm /encoder count
Support structure
adjustment ranges
Longitudinal
± 10 mm
Vertical
± 10 mm
Lateral
± 10 mm
Horizontally defining slit (HDS)
Slit blades
Material
stainless steel 1.7218 with hardened knife edge and gold coating
Straightness
< 0.15 µm over 10 mm (1σ)
Parallelism
0.01 µm /mm
(10 µm slit opening)
0.006 µm /mm
(25 µm slit opening)
0.03 µm /mm
(50 µm slit opening)
Slit opening
Range
5.8 µm to 8 mm
Repeatability
± 0.03 µm
(up to 350 µm slit opening)
Resolution (design value)
0.003 µm /motor fine step
(1/32, recommended)
0.01 µm /encoder count
Slit translation
transversal to the beam axis
Range
8 mm
Resolution (design value)
0.003 µm /motor fine step
(1/32, recommended)
0.01 µm /encoder count
Vertically defining slit (VDS)
Slit blades
Material
stainless steel 1.7218 with hardened knife edge
Straightness
< 0.25 µm over 10 mm (1σ)
Parallelism
0.07 µm /mm
(10 µm slit opening)
0.04 µm /mm
(25 µm slit opening)
0.02 µm /mm
(50 µm slit opening)
Slit opening
Range
5.5 µm to 9.7 mm
Repeatability
± 0.05 µm
(up to 350 µm slit opening)
Resolution (design value)
0.003 µm /motor fine step
(1/32, recommended)
0.01 µm /encoder count
Slit rotation
Range
± 1° (in air )
± 0.5° (in UHV)
Slit width variation upon slit rotation
0.77 µm (1σ)
Performance Test Results
Slit width calibration (HDS)
Slit opening repeatability (HDS)
Slit blades parallelism (HDS)
Slit blades parallelism (HDS)
Slit blades parallelism (HDS)
Slit width calibration (VDS)
Slit opening repeatability (VDS)
Slit blades parallelism (VDS)
Slit blades parallelism (VDS)
Slit blades parallelism (VDS)
Slit width variation upon slit rotation (VDS)
