CoESCA

Coincidence Electron Spectroscopy for Chemical Analysis at UE52-PGM

CoESCA is equipped with two Angle-Resolved Time-Of-Flight spectrometers to measure the 3D angular resolved electron distributions, either independently or in coincidence mode. Shot-to-shot data saving for each of the spectrometers allows for investigating the time evolution of the data and post-processing on slow time scales from minutes to hours. The ArTOFs’ high information rate makes studies of radiation sensitive samples at very low photon flux feasible even in a reasonable acquisition time.

Anwendungsbeispiele:
  • Electronic structure of solids with one-hole (XPS, ARPES) and two-hole (APECS) final state spectroscopies
  • Structural information of surfaces and adsorbates with photoelectron diffraction
  • Enhanced surface sensitivity and spectral filtering possibilities in coincidence mode
CoESCA end-station layout

CoESCA end-station layout


Methods

XPS, UPS, ARPES

Remote access

depends on experiment - please discuss with Instrument Scientist

Beamline data
Energy range 115 - 1600 eV
Energy resolution > 10000 at 400 eV
Flux 1012
Polarisation variable
Focus size (hor. x vert.) 100 μm x 30 μm
Phone +49 30 8062 14692
Weitere Details UE52_PGM CoESCA
Station data
Temperature range ~30 - 1000 K
Pressure range 2 · 10-10 mbar
Detector • Scienta ArTOF10k prototype (30° angular acceptance)
• Scienta ArTOF2-EW (56° angular acceptance)
Manipulators 5 axis heated and cooled manipulator
Sample holder compatibility Omicron-flag-style sample plates
Additional equipment • preparation chamber: sample heating stage (up to 800°C), quartz balance, mass spectrometer and free ports for mounting user provided equipment (e.g. evaporators)
• users-provided preparation chambers may be connected additionally

The COincidence Electron Spectroscopy for Chemical Analysis station is at a plane grating monochromator beamline with a UE-52 undulator. The beamline offers photons in linear polarisation from 110-1900 eV and in elliptical polarisation from 110-1390 eV and can be switched in “one-click” between mutli-bunch and the quasi single bunch PPRE mode (PPRE: pulse-picking by resonant excitation).

The CoESCA station is equipped with two Angle-Resolved Time-Of-Flight spectrometers, one ArTOF 10k prototype with an angular acceptance of 30° and one ArTOF2-EW with a wider angular acceptance of 56°. Thus both spectrometers measure the 3D angular resolved electron distributions. Further they can be operated either independently or in coincidence mode.  The data is saved shot-to-shot for both spectrometers and hence the time evolution of the data can be investigated in post-processing on slow time scales from minutes to hours. The ArTOFs’ high information rate makes studies of radiation sensitive samples at very low photon flux feasible even in a reasonable acquisition time.

The main experimental chamber features a 5-axis sample manipulator, with the possibility to cool or heat the sample (T = 30-1200 K), put up a bias voltage and measure the sample current for basic absorption measurements. The end-station is equipped with sample loading, storing and preparation facilities. The preparation chamber is equipped with a sample heating stage (up to 800°C), a quartz balance, a mass spectrometer and free ports for mounting user provided equipment (e.g. evaporators). Furthermore, the transfer system is ready for additional, users-provided preparation chambers.