Compact ARPES Analyser with Deflection Capability
- 20° 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 deflection technology that was previously only available in the larger DA30-L analyser models, enabling full cone ARPES measurements without sample rotation. This allows electronic band structure mapping of the surface Brillouin zone without changing measurement geometry, eliminating matrix element effects, and simplifying the interpretation of results dramatically.
The DA20 analyser is a highly flexible state-of-the-art analyser optimised for quick high-resolution PES measurements using a 135 mm mean radius hemispherical electron analyser. It is designed for high throughput and compact foot print. It is well suited for XPS and UPS measurements and additionally offers advanced ARPES measurement capability.
Traditional ARPES analysers have an angular mode which is restricted to the angular dispersive θx direction. The detector records a 2D image of intensity for angle θx vs energy E. In such a setup, obtaining full cone measurements requires the sample to be physically rotated to probe the θy angular space. This physical movement can introduce multiple artefacts into the ARPES measurement.
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, and E values.
The deflection mode enables the DA20 to obtain these full cone measurements with an opening angle of up to ± 10° while avoiding sample rotation, making it an ideal workhorse for ARPES measurements.
The DA20(R) comes with transmission as well as angular lens modes and is mechanically fully prepared for the ground-breaking and proven deflection capabilities with which Scienta Omicron has revolutionised ARPES measurements. The HV electronics and software necessary for the deflection mode can be upgraded at customer site, without removing the analyser from the system, and without breaking vacuum. Hence, this option presents an easy path to gain future access to the DA20 deflector capability.
The deflection feature is a big advantage as it allows to keep the sample in a fixed position and instead uses the deflectors to change the angular range in θy projected on to the analyser slit. This ensures the same position of the sample is probed during the whole measurement. In addition, keeping the experimental geometry fixed throughout the measurement sequence avoids matrix element effects which are caused by variations in ionisation cross section for different photon to sample angles. This allows to acquire higher quality data using the faster and more precise electronic deflection compared with mechanical sample movement. Another advantage, for some samples, is that decreased rotation requirements allow manipulators with fewer degrees of freedom to be used. This ultimately allows for lower sample temperatures to be reached.
< 3 meV FWHM
0.5 eV – 1 500 eV
3 eV – 1 500 eV
For full specifications and more information about product options, please do not hesitate to contact your local sales representative.
3 eV – 200 eV
< 10-5 mbar
NW 100 CF
Compact XPS/UPS/ARPES Analyser with Patented Deflection
The DA20 is a compact analyser for high energy resolution measurements required in XPS and ARPES applications. In addition, the analyser is capable of measuring a full cone of ± 10 degrees opening angle without sample movement making it ideally suited for ARPES.