Speaker
Description
Understanding photoinduced structural and electronic dynamics in chemical and biological systems requires experimental tools with femtosecond time resolution and sensitivity at the atomic scale. In this context, we describe the Alvra instrument at the Swiss X-ray free-electron laser (SwissFEL), which was developed to address these challenges by combining time-resolved X-ray spectroscopy and scattering techniques.
Alvra operates on the hard X-ray ARAMIS beamline and is primarily used to investigate ultrafast structural and electronic processes in photochemical and photobiological systems. It provides access to photon energies between 2 and 15 keV and integrates, within a single experimental environment, spectroscopic methods such as X-ray absorption (XAS), X-ray emission (XES), and resonant inelastic X-ray scattering (RIXS), together with structural techniques like X-ray solution scattering (XSS) and serial femtosecond crystallography (SFX). The setup is organized into two endstations, Prime and Flex, which together support experiments on liquids, crystalline samples, and solid-state systems, as well as user-built configurations.
One of the key aspects of Alvra is its ability to carry out time-resolved XES and RIXS in the tender X-ray regime, which is still not widely available at other XFEL facilities. In addition, advanced optical laser systems and shot-to-shot timing diagnostics enable pump probe experiments with temporal resolutions below 35 fs, under well-controlled conditions.
Since the beginning of user operation in 2019, a broad range of chemistry and biology experiments have been performed in Alvra. These studies have helped to understand the evolution of the transient electronic states and structural dynamics. As the user base grows and new methods are developed, the instrument continues to evolve in response to experimental needs.
| Scientific Topics | Chemistry |
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