---

The instrumentation required for Photoemission Electron Microscopy (PEEM) and its variant using X-ray excitation (XPEEM), Angle-Resolved Photoelectron Spectroscopy (ARPES) and Resonant Inelastic X-ray Spectroscopy (RIXS) is usually completely different. PEEM and XPEEM use imaging microscope columns, ARPES uses electron spectrometers, primarily hemispherical ones, whereas RIXS requires high-resolution
X-ray spectrometers with long optical paths to achieve the desired resolution. In a special time-of-flight photoelectron microscope, we combined in one electron column similar to a PEEM, photoelectron momentum microscopy (MM) [1] – imaging of the backfocal plane of the objective lens, a powerful ARPES approach – with the concept of PAXRIXS [2]. Here, the RIXS photon spectrum is ‘translated’ into a photoelectron spectrum using an ultrathin converter foil. In this configuration, the microscope operates in XPEEM mode, capturing real-space (Gaussian) images of the converter foil, which has a diameter of several millimeters.
The position at which a RIXS photon hit the converter is a measure for the momentum transfer.
The setup thus combines four operating modes: Real-space imaging using UV excitation (for checking the probing region), XPEEM for checking the chemical composition (with resolution down to the 100nm range),
k-imaging for ARPES (with performance comparable to conventional ARPES) and XPEEM at a core level of
the converter foil for capturing the RIXS spectrum and band dispersion. Switching between the modes can be done without moving the sample, thus keeping the probing spot fixed. In the MM mode with removed converter, the distance between the sample and extractor electrode is large (typically 14 mm). For RIXS,
the converter foil is moved between the sample and the extractor, and fields-of-view of several mm are imaged – far beyond usual fields-of-view in PEEM or XPEEM. This is facilitated by a novel type of front lens which enables various operating modes [3]. Ultrathin Au, Ag, and Pt converter foils provide energy resolutions between 20 meV and 400 meV.

[1] Medjanik et al., Nat. Mater 16, 615 (2017);
[2] Dakovski et al., J. Synchrotron Radiat. 24 (2017) 1180;
[3] Tkach et al., Ultramic.276 (2025) 114167.

---