The materials science X-ray beamline BL8 at the DELTA storage ring

Abstract

The hard X-ray beamline BL8 at the superconducting asymmetric wiggler at the 1.5 GeV Dortmund Electron Accelerator DELTA is described. This beamline is dedicated to X-ray studies in the spectral range from approximately 1 keV to approximately 25 keV photon energy. The monochromator as well as the other optical components of the beamline are optimized accordingly. The endstation comprises a six-axis diffractometer that is capable of carrying heavy loads related to non-ambient sample environments such as, for example, ultrahigh-vacuum systems, high-pressure cells or liquid-helium cryostats. X-ray absorption spectra from several reference compounds illustrate the performance. Besides transmission measurements, fluorescence detection for dilute sample systems as well as surface-sensitive reflection-mode experiments have been performed. The results show that high-quality EXAFS data can be obtained in the quick-scanning EXAFS mode within a few seconds of acquisition time, enabling time-resolved in situ experiments using standard beamline equipment that is permanently available. The performance of the new beamline, especially in terms of the photon flux and energy resolution, is competitive with other insertion-device beamlines worldwide, and several sophisticated experiments including surface-sensitive EXAFS experiments are feasible.

X‐Ray Near‐Edge Absorption Study of Temperature‐Induced Low‐Spin‐to‐High‐Spin Change in Metallo‐Supramolecular Assemblies

“…[22] For Fe(phen) 2 (NCS) 2 , the XANES measurements were acquired in transmission mode using N 2 -and Ar-filled ionization chambers as detector. For energy calibration, a metallic iron foil was measured as reference simultaneously to each sample scan.…”

“…The collection of the XANES spectra at the iron K edge (7112 eV) was performed on the material science X-ray beamline BL8 at the 1.5 GeV DELTA storage ring (Dortmund) using a Si(111) double crystal monochromator. [22] For Fe(phen) 2 (NCS) 2 , the XANES measurements were acquired in transmission mode using N 2 -and Ar-filled ionization chambers as detector. For energy calibration, a metallic iron foil was measured as reference simultaneously to each sample scan.…”

“…Secondly, this compound is one of the most widely investigated iron SCO complexes, which makes it a good candidate as a test material in the newly built beamline at DELTA synchrotron. [22] 2. Results Figure 1 shows the XANES profiles, at the iron K edge, of LS and HS PAC containing 2 (a) and 6 (b) amphiphilic molecules below and above the thermally induced LS to HS change.…”

Operando XAS Techniques: Past, Present, and Future

“…Time-resolved data can be obtained by either quick EXAFS (QEXAFS) or by energy dispersive XAS (EDXAS), both needing a dedicated beamline setup with specific additional components. Quick EXAFS (taken in seconds up to minutes depending on scan rate and applied monochromator setup) has been reported [105], but even the high speeds possible on the super-XAS beamline at the Swiss Light Source, as reported by Frahm et al [106] are still too slow for most shortlived intermediates. Tada et al [107] have reported operando time-resolved results on a Pt/C cathode in a fuel cell using a "time-gated" QEXAFS (TG-QEXAFS) procedure giving a time resolution of 1 s. Figure 17.14 shows a schematic of how the QEXAFS and potentiostat system were synchronized with a trigger signal sent from the potentiostat to the QEXAFS system allowing the data to be taken in 1-s intervals and effectively "splicing" together 15 different spectra.…”

Analysis of engine motor oils by X-ray absorption and X-ray fluorescence spectroscopies

“…All the X‐ray experiments have been performed at the materials science beamline BL8 at the DELTA storage ring (Dortmund, Germany) operating with 1.5 GeV electrons and 80–130 mA of stored current. A double crystal monochromator with two flat Si(111) crystals and an energy resolution of about ΔE/E ≈ 1.3 × 10 −4 was used.…”