The orange Book: ESRF UPGRADE PROGRAMME PHASE II (2015 - 2022)

The strength of modern X-ray science is its endeavour to provide unique tools and methods to understand and picture how atoms make and evolve the living matter and the materials that both surround us and of which we are constituted. Understanding materials for electronic devices and for storing and producing new forms of renewable and non-polluting energy, and unravelling the mysteries of biological reactions are examples of key challanges for which we need to improve our capacity to design future materials, processes, drugs, etc. These ambitious goals of 21st century science require fundamental understanding and visualisation of the hierarchical static and dynamic organisation of complex and functionalised matter with full continuity from macroscopic objects down to interactions among single atom pairs. Future X-ray science at modern synchrotrons and XFELs will bridge the gap between visible light and electron microscopy, i.e. it will give full access to study changes within heterogeneous atomic assemblies from ~1012 atoms down to only a few atoms; all of this with spatial and temporal resolutions that will be approaching a few atoms in space (nanometre) and inter-atomic motion in time (femtosecond) respectively. Such incredible resolution and range in space and time are made possible by the absolutely impressive and never-ending improvements of brightness, spectral range and degree of spatial and temporal coherence and resolution of accelerator-based X-ray sources. During the last ~50 years peak-brightness has increased up to 22 orders of magnitude when compared to conventional laboratory sources.