ARPES-Lab

The Top End Solution for ARPES

The UHV System Concept

The UHV system is a customizable surface analysis solution for highest performance ARPES studies especially developed for the DA30-L analyser. Scienta Omicron has a long tradition of system design and will therefore fully guarantee the performance of the ARPES solution. The system is designed and optimized for best performance with lab or synchrotron based laser, UV and X-ray sources. Scienta Omicron systems are also prepared for multi-technique upgrades with possibilities of adding SPM and MBE capabilities to the system. The system configuration and layout will be developed and upon request updated in collaboration with the customer during the lifetime of the system.

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The DA30-L Analyzer

With the introduction of the DA30 analyser family, the development of the hemispherical analyser takes a quantum leap. Using a new deflector concept (patent pending) these novel analysers can sequentially measure electrons in a full cone of 30 degrees opening angle. This development opens up for band mapping of the full surface Brillouin zone without the need to rotate the sample.


In combination with the available spin detection systems the DA30-L also allows for spin-resolved measurements of the full cone acceptance without sample rotation. This represents a major breakthrough in spin-resolved measurements, since spin-resolved measurements could previously only be recorded for electron emitted parallel to the lens axis, and contributes to a substantial reduction in acquisition times.


The high voltage electronics provides ultra stable conditions for reliable accurate measurements. Electron detection is realised by a modern 2-D low noise digital CCD-MCP detector system with a noise level of < 0.01 cps/channel. Furthermore the analyser is equipped with real time read-out and electronic analyser lens X/Y deflectors for diagnostics and experimental optimisation purposes.

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Analysis Chamber

A stainless steel chamber with single mu-metal liner is the standard choice for state-of-the-art high resolution measurements of kinetic energies typically generated by UV excitation. The chamber will be made of stainless steel grade AISI 316 L (Flanges: AISI 304) and provided with a single mu-metal liner. The guaranteed residual magnetic field in the critical volume around the analysis spot is specified < 0.5 μT. This will be measured and verified before delivery.

For ultra-high resolution at the lowest energies, typical for laser excitation, a stainless steel chamber with double mu-metal liner giving a guaranteed residual magnetic field < 0.1 μT is recommended. This is the preferred choice for high resolution studies of electrons below 10eV kinetic energy and is available as an option.

The chamber offers ports for the DA30-L analyser, excitation sources, e.g. VUV and X-ray sources, charge neutralization, sputter gun, pumps, pressure measurement, viewports, manipulator, and sample transfer. The configuration discussion will be initiated from a Scienta Omicron well accepted standard design.

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Frame

The vacuum system is mounted on a rigid steel frame with ±5mm height-adjustable mounting feet, so that attachment to an adjacent vacuum system is easily possible. The DA30-L analyser can in the design phase be orientated with the energy dispersive plane horizontal or vertical. The bench is optimized for small footprint and prepared for future system upgrades and extensions.

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Analysis Chamber Vacuum System

The design of the chamber and the pumping configuration is optimized for the ARPES-Lab operation. The specified base pressure is <1E-10 mbar. The pumping system consists of:

  • Ion getter pump
  • Titanium sublimation pump
  • Turbomolecular pump
  • Rotary backing pump
  • Pneumatically operated gate valve between turbo pump and UHV chamber
  • Thoriated iridium twin filament ion gauge for pressure measurement
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