Constantin Wansorra received outstanding presentation award at the HAXPES 2024 conference

The 10th HAXPES conference in Pilsen brought together 120 scientists from all over the world, which enabled fruitful discussions in this rather small and highly-specialized environment.

Changing the photoelectron kinetic energy in hard x-ray photoelectron spectroscopy (HAXPES) and thus their attenuation length, has become a common method in recent years to probe the depth-dependent elemental ratio of materials. This is achieved by variation of the energy of the exciting photons and thus requires a precise knowledge of  excitation-energy-dependent partial photoionization cross sections (PPICS). PPICS generally originate from calculations and vary by orders of magnitude in the commonly-used excitation energy range. This raises the question: to what extent can the calculated values be trusted, and what deviations can be expected at different energies?

Using the wide and gapless energy range of the X-SPEC beamline at the KIT Light Source, Dr. Constantin Wansorra and the IPS spectroscopy group measured PPICS of reference materials and compared them with calculations of different authors. While the measurements agree with the calculations at most photon energies (within expected uncertainties), strong deviations are observed in some energy regions that have to be considered in the evaluation of HAXPES data.