X-Treme beamline at SLS: X-ray magnetic circular and linear dichroism at high field and low temperature

X-Treme is a soft X-ray beamline recently built in the Swiss Light Source at the Paul Scherrer Institut in collaboration with Ecole Polytechnique Federale de Lausanne. The beamline is dedicated to polarization-dependent X-ray absorption spectroscopy at high magnetic fields and low temperature. The source is an elliptically polarizing undulator. The end-station has a superconducting 7 T-2 T vector magnet, with sample temperature down to 2 K and is equipped with an in situ sample preparation system for surface science. The beamline commissioning measurements, which show a resolving power of 8000 and a maximum flux at the sample of 4.7 x 10(12) photons s(-1), are presented. Scientific examples showing X-ray magnetic circular and X-ray magnetic linear dichroism measurements are also presented

Droplet-based in situ X-ray absorption spectroscopy cell for studying crystallization processes at the tender X-ray energy range

The understanding of nucleation and crystallization is fundamental in science and technology. In solution, these processes are complex involving multiple transformations from ions and ion pairs through amorphous intermediates to multiple crystalline phases. X-ray absorption spectroscopy (XAS), which is sensitive to liquid, amorphous and crystalline phases offers prospects of demystifying these processes. However, for low Z elements the use of in situ X-ray absorption spectroscopy requires the tender X-ray range, which is often limited by vacuum requirements thereby complicating these measurements. To overcome these challenges, we developed a versatile and user-friendly droplet-based in situ X-ray absorption spectroscopy cell for studying crystallization processes. Time-resolved in situ experiments under ambient conditions are carried out in the cell whilst the cell is mounted in the vacuum chamber of a tender X-ray beamline. By following changes in the Ca K-edge X-ray absorption near edge structure (XANES), we captured in situ the intermediate phases involved during calcium carbonate crystallization from aqueous solutions. In addition, through linear combination fitting it was possible to qualitatively observe the evolution of each phase during the reaction demonstrating the potential of the cell in studying complex multiphase chemical processes.ISSN:2046-206

A new endstation at the Swiss Light Source for ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy measurements of liquid solutions

ISSN:0034-6748ISSN:1089-762