CohereX 2026 is a French thematic school dedicated to the use of coherent X-rays produced by third- and fourth-generation synchrotrons and X-ray free-electron laser (XFEL) sources.

In a context marked by the rise of so-called “extremely brilliant” sources and the rapid expansion of XFEL facilities, exploiting X-ray beam coherence opens up unprecedented scientific opportunities. These approaches enable the investigation of structure and dynamics in matter—from metals, semiconductors, and magnetic materials to biological systems and soft matter—across spatial scales ranging from the angstrom to the micrometer and temporal scales from the femtosecond to the second. At the same time, recent upgrades of major international synchrotron facilities, the growing availability of XFEL sources, and rapid advances in detectors, optics, and digital tools (AI, GPU computing) place the community at a pivotal moment in the history of X-ray science.

The primary objective of CohereX 2026 is to provide the next generation of users with a strong foundation of knowledge and practical skills in methods based on coherent X-rays. The school aims to offer a broad and up-to-date overview of coherence-based approaches at synchrotron and XFEL facilities. It seeks to train participants in the associated experimental and computational tools, foster interdisciplinary exchanges among physicists, opticians, chemists, signal-processing specialists, and computational scientists, and contribute to strengthening the structuring of the international community.