CoESCA
Coincidence Electron Spectroscopy for Chemical Analysis /UE52
The Coincidence ESCA instrument is installed at the UE52 undulator, featuring a plane-grating monochromator which delivers soft X-ray radiation with variable polarization. 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 multi-bunch and the quasi single bunch PPRE mode (PPRE: pulse-picking by resonant excitation).
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.
Selected Applications:- 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
Methods
ARPES, XPS, XPD, LEED, XPD, XMCD, NEXAFS, Mass Spectrometry
Remote access
depends on experiment - please discuss with Instrument Scientist
| Instrument data | |
|---|---|
| Phone (~49 30 8062-) | 14692 |
| Beam availability | 12h/d |
| Source | UE52 (Elliptical Undulator) |
| Monochromator | PGM |
| Energy range (at experiment) | tbd |
| Energy resolution | > 10000 at 400 eV |
| Flux | 1012ph/s |
| Polarisation | variable |
| Focus size (hor. x vert.) | 200 μm x 100 μm |
| Temperature range | ~30 - 1000 K |
| Pressure range | 2 · 10-10 mbar |
| Detector | Two Scienta ArTOF2-EW (60° angular acceptance) |
| Manipulators | 5 axis heated and cooled manipulator |
| Sample holder compatibility | Omicron-flag-style sample plates |
| Additional equipment |
|
| Additional information | Detaisl beamline UE52-PGM CoESCA |
The CoESCA station is equipped with two ArTOF2-EW (SCIENTA OMICRON) spectrometers, with a wide angular acceptance up to 60° (full cone). 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, user-provided preparation chambers.