%0 Journal Article
%A Schönhense, G.
%A Medjanik, K.
%A Fedchenko, O.
%A Zymakova, Anna
%A Chernov, S.
%A Kutnyakhov, Dmytro
%A Vasilyev, D.
%A Babenkov, S.
%A Elmers, H. J.
%A Baumgärtel, P.
%A Goslawski, P.
%A Öhrwall, G.
%A Grunske, T.
%A Kauerhof, T.
%A von Volkmann, K.
%A Kallmayer, M.
%A Ellguth, M.
%A Oelsner, A.
%T Time-of-flight photoelectron momentum microscopy with 80–500 MHz photon sources: electron-optical pulse picker or bandpass pre-filter
%J Journal of synchrotron radiation
%V 28
%N 6
%@ 0909-0495
%C [S.l.]
%I Wiley-Blackwell
%M PUBDB-2021-05248
%P 1891 - 1908
%D 2021
%X The small time gaps of synchrotron radiation in conventional multi-bunch mode (100-500 MHz) or laser-based sources with high pulse rate (similar to 80 MHz) are prohibitive for time-of-flight (ToF) based photoelectron spectroscopy. Detectors with time resolution in the 100ps range yield only 20-100 resolved time slices within the small time gap. Here we present two techniques of implementing efficient ToF recording at sources with high repetition rate. A fast electron-optical beam blanking unit with GHz bandwidth, integrated in a photoelectron momentum microscope, allows electron-optical 'pulse-picking' with any desired repetition period. Aberration-free momentum distributions have been recorded at reduced pulse periods of 5 MHz (at MAXII) and 1.25 MHz (at BESSYII). The approach is compared with two alternative solutions: a bandpass pre-filter (here a hemispherical analyzer) or a parasitic four-bunch island-orbit pulse train, coexisting with the multi-bunch pattern on the main orbit. Chopping in the time domain or bandpass pre-selection in the energy domain can both enable efficient ToF spectroscopy and photoelectron momentum microscopy at 100-500 MHz synchrotrons, highly repetitive lasers or cavity-enhanced high-harmonic sources. The high photon flux of a UV-laser (80 MHz, <1 meV bandwidth) facilitates momentum microscopy with an energy resolution of 4.2 meV and an analyzed region-of-interest (ROI) down to < 800 nm. In this novel approach to `sub-mu m-ARPES' the ROI is defined by a small field aperture in an intermediate Gaussian image, regardless of the size of the photon spot.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 34738944
%U <Go to ISI:>//WOS:000715906300024
%R 10.1107/S1600577521010511
%U https://bib-pubdb1.desy.de/record/472792