Acquisition of photoelectron diffraction patterns with a two-dimensional wide-angle electron analyzer

Abstract

An efficient and fast way to measure photoelectron diffraction data over the full 2 angular range with high data point density is presented, taking advantage of the massive parallel detection capabilities of modern two-dimensional electron detectors. We introduce generic routines for data binning and for the mapping of the detector signal onto emission angles. X-ray photoelectron diffraction patterns taken from Bi(1 1 1) with the new detection scheme are compared to data sets taken with a conventional hemispherical analyzer equipped with a channeltron detector. As a result, the data acquisition time can be reduced by roughly a factor of ten while obtaining comparable if not superior data quality. The sampling technique is extended to UV-excited angle-resolved photoelectron spectroscopy as illustrated by a mapping of the Fermi surface of Cu (1 1 1 AbstractAn efficient and fast way to measure photoelectron diffraction data over the full 2π angular range with high data point density is presented, taking advantage of the massive parallel detection capabilities of modern two-dimensional electron detectors. We introduce generic routines for data binning and for the mapping of the detector signal onto emission angles. X-ray photoelectron diffraction patterns taken from Bi(111) with the new detection scheme are compared to data sets taken with a conventional hemispherical analyzer equipped with a channeltron detector. As a result, the data acquisition time can be reduced by roughly a factor of ten while obtaining comparable if not superior data quality.The sampling technique is extended to uv-excited angle-resolved photoelectron spectroscopy as illustrated by a mapping of the Fermi surface of Cu(111).

h-BN/Metal-Oxide Interface Grown by Intercalation: A Model System for Nano-Confined Catalysis

“…All XPD patterns, from both experimental and simulated data, were plotted in IgorPRO using custom-made macros. The algorithms behind these plugins are extensively described by Greif et al 55 These data were then exported into ImageJ where a Gaussian blur with a reduced standard deviation (σ r ) of 5.0 was used to interpolate the diffractogram.…”

Light-Matter Interaction at Surfaces in the Spatiotemporal Limit of Macroscopic Models

“…Subsequently, both beams are focused by a toroidal mirror into a first interaction region, where a gas nozzle is placed. An additional toroidal mirror placed after the gas target collects the beams and reimages the first focus into a second interaction region where a surface-science end station, equipped with a hemispherical electron analyzer, is installed [12]. Figure 1 displays a schematic of the sample surface orientation.…”

Surface science at the PEARL beamline of the Swiss Light Source

“…Assuming that the angular dependence of the matrix element can be neglected (e.g. by normalization), instrument coordinates are mapped to sample coordinates by applying a series of rotations to the Cartesian vector k = ðcos ; 0; sin Þ which marks the detection angle in the laboratory frame of reference (Greif et al, 2014). In the sample frame, the emission vector k s becomes, thus…”

“…9(c). Processing of angle-scanned XPD data from a twodimensional electron analyser is more complex than from conventional channeltron-based detectors because the measured angle distribution is modified by additional physical and instrumental effects (Greif et al, 2014). Such effects include the angular dependence of the differential photoionization cross section, the cross section of the illuminated and the analysed volume, as well as angular inhomogeneities of the electron lens and the detector (transmission function).…”