Characterization of the OctoIonGuide setup for high-resolution photoionization studies of low-charge atomic ions

This paper describes the design and experimental validation of the OctoIonGuide, a compact setup for high-resolution photoionization studies of low-charge atomic ions with synchrotron radiation. The system integrates an axial ion source, a 40 cm RF octupole ion guide, and a quadrupole mass analyser, providing precise ion transport and mass selection. A proof-of-principle experiment on Xe + ions in the 20–22 eV range demonstrated the ability to resolve Rydberg resonances converging to the Xe 2+ . The recorded spectra showed excellent agreement with reference data, confirming the accuracy and reliability of the setup. The novelty of this work lies in combining these components into a single, integrated platform, offering improved ion handling and compatibility with synchrotron and free-electron laser facilities. The OctoIonGuide represents a versatile tool for studying ionization dynamics relevant to laboratory astrophysics and plasma physics.