DA20

Compact ARPES Analyser with Patented Deflection Capability

At a glance

  • 20° degrees full cone acceptance without sample rotation
  • Fast and patented electronic deflection (WO2013/133739)
  • Matrix element effects are avoided by keeping sample fixed
  • Ensures same spot size and shape for all k//
  • Manipulator requirements are reduced

The DA20 provides ARPES as well as XPS and UPS while maintaining a compact footprint. The DA20 includes the ground-breaking and patented deflection technology that was previously only available in the larger DA30 enabling full cone ARPES measurements without sample rotation. 

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Deflector Concept

Traditional ARPES analysers have an angular mode which is restricted to the angular dispersive θx direction, resulting in a 2D image of intensity for angle θx and energy E on the 2-D detector. In such a set-up, obtaining full cone measurements requires the sample to be physically rotated to probe the θy angular space. This physical movement can introduce multiple artifacts into the ARPES measurement. First order issues include measuring different areas of the sample as the sample is moved. Matrix effects are also introduced as incident and exit angles are changed, affecting angle dependent electron escape.

Our analysers overcome these limits by using an internal deflection mode for the θy direction. With this deflection mode, the lens system projects individual slices of θx on to the analyser slit for a given θy angle. Hence, the detector of hemispherical analyser measures slices of θx vs E spectra. Recording these individual slices while changing the θy deflector angle builds a cube of reliable data containing intensity for all θx, θy, E values.

The deflection mode enables the DA20 to obtain these full cone measurements with an opening angle of up to ± 10 degrees while avoiding sample rotation, making it an ideal workhorse for ARPES measurements.

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