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O: Fachverband Oberflächenphysik

O 92: Poster Session - Ultrafast Electron Dynamics at Surface and Interfaces II

O 92.7: Poster

Mittwoch, 18. März 2020, 18:15–20:00, P2/1OG

Momentum Microscope vs. Hemispherical analyzer - a quantitative comparison of electron analyzer performance for time-resolved ARPES experiments — Julian Maklar, Tommaso Pincelli, Samuel Beaulieu, Shuo Dong, Maciej Dendzik, Martin Wolf, Ralph Ernstorfer, and •Laurenz Rettig — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

For angle-resolved photoelectron spectroscopy (ARPES), an important element is the employed electron analyzer. While hemispherical analyzers with angle-dispersing electron lenses have been the working horse for decades, recently time-of-flight based momentum microscopes have shown a huge improvement in parallel detection efficiency, allowing for simultaneous detection of multiple Brillouin zones without the need to rearrange the sample geometry. However, one drawback of such instruments, in particular in time-resolved studies, arises from the large energy and momentum range covered simultaneously, which in combination with detection limitations of delay-line detectors can severely reduce the effective detection rate for selected energy-momentum regions compared to conventional hemispherical analyzers. Additionally, the high electron energies employed in the more complex electron lens system designs impose new constraints in terms of space charge. Using our XUV time-resolved ARPES system hosting both a hemispherical analyzer (SPECS Phoibos 150) and a momentum microscope (SPECS Metis 1000) in one experimental setup, we quantitatively compare the advantages and disadvantages of both types of analyzers for various kinds of trARPES experiments.