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Precision Slit Unit

Precision slit units open symmetrically and feature exceptional blade parallelism and straightness at a wide opening range. They are designed and built using well-proven modules and principles combining ultra-high precision and repeatability with a robust design for reliable operation. Each unit is custom-tailored according to the requirements at the specific installation site.


The nonlinear characteristic of the symmetrically opening slit mechanism allows for setting small slit openings with highest accuracy, whereas bigger openings are set very fast.


  • Double slit mechanism.
  • Longitudinal travel of the unit along beam direction.
  • Transversal slit translation.
  • Tunable slit orientation (rotation around beam axis).
  • Slit blade materials: OFHC, W, Mo, B4C, Au coating.
  • Blade cooling.
  • Ellectrically isolation of blades.
  • Motion control system.

Performance parameters

Performance parameter values for individual projects may well exceed the values listed below.

Slit blades

Edge straightness

< 0.1 µm /mm (OFHC)


< 0.1 µm /mm

Slit opening


0 – 10 mm


< 0.1 µm

Slit rotation


± 1°

Spurious slit opening

< ± 0.5 µm

Transversal translation


± 5 mm

Spurious slit opening

< ± 0.2 µm

Longitudinal translation


< 1000 mm


0.05 µm

Performance Test Results

Slit width calibration
Slit opening repeatability
Slit blades parallelism
Slit blades straightness


Slit units are essential components of monochromator beamlines at synchrotron radiation sources. They serve as wavelength selector for the energy-dispersed radiation and as beam shapers for intermediate foci.


Selected Projects