Dismantling a world-record breaking X-ray facility, after nearly 30 years of scientific success, may seem surprising. The European Synchrotron Radiation Facility (ESRF) was placed into standby mode on 10^th December 2018, 30 years after the ESRF convention was first signed, to make way for a revolutionary new synchrotron, the Extremely Brilliant Source (EBS).

The ESRF made history as the world’s first third-generation synchrotron light source, producing X-rays 100 billion times brighter than the X-rays used in hospital radiographic equipment, and providing unrivalled opportunities for scientists in the exploration of materials and living matter. In its lifetime, the scientific output that emerged from ESRF instruments has totalled over 32,000 scientific publications, and it has created four Nobel Prize laureates.

What is a synchrotron?

A synchrotron differs from commonplace, hospital X-ray equipment in that it is an extremely powerful source of radiation. X-rays are produced as high-energy electrons are accelerated around the massive, circular tunnel of the synchrotron. As the moving electrons are made to change direction periodically, they emit X-ray wavelength radiation. They emerge as several thin beams of radiation, which can be directed into instruments that utilise the X-rays in scientific experiments.

The brilliance and quality of the X-rays produced by a synchrotron function like a ‘super-microscope’, which ‘films’ the position and motion of atoms in condensed and living matter, and reveals the structure of matter down to the atomic level. The ESRF has developed non-destructive techniques, and thus can be used to analyse a range of materials without damaging them.

The power of X-rays

Researchers at the ESRF have pioneered some of the most innovative research across a range of fields, including biomedical, materials science, cultural heritage, environmental sciences and physics. The brilliance and quality of the X-ray beams provided by the ESRF have enabled unprecedented structural analysis to be performed in the past few decades. Equally, the demand for experimental time spent with the ESRF equipment has increased year upon year, with thousands of scientists from across the worlds coming to Grenoble to use the state-of-the-art instruments, which operate 24 hours a day, 7 days a week. However, pioneering synchrotron science and pushing the limits of the exploration of matter requires the building of more coherent and brighter synchrotron light source. With EBS, this quest for brilliance and coherence reaches a new step.

The evolution of synchrotrons is commonly described in terms of generations. If the ESRF was the first third-generation synchrotron, EBS will be the world’s first high-energy 4^th generation synchrotron. Due to open in 2020, EBS is a €150 million project, funded by the 22 partner countries of the ESRF. It sets a new standard for synchrotron storage rings, with unique performances increased by a factor 100 in terms of brilliance and coherence compared to third generation standards.

Europe has always been a pioneer in synchrotron science, though other facilities around the world exchange and build on the innovation of others. For example, the Advanced Photon Source (APS) Storage Ring Upgrade under construction at the Argonne National Laboratory in Illinois, USA, features a magnet lattice ( a sequence of magnets, which, repeated many times, nsures the bending of the electron beam) based on that proposed and developed by the ESRF, and implemented in the EBS upgrade.

Though the engineering design and realisation of the APS Storage Ring Upgrade is fully developed at the APS, APS have adopted solutions that are based on the acquired know-how of EBS and MAX IV Laboratory in Lund, Sweden, but in many cases go beyond them (in particular for magnet and vacuum system design).

It is critical that the global scientific community continues to push the boundaries of science and engineering to develop bigger and more capable X-ray sources than ever before, as the demand for experimental time in these facilities is so great. Researchers around the world will have more opportunity to conduct studies using these exceptional instruments, improving the quality of research across all scientific fields.

A creative constructional challenge

The upgrade is an enormous challenge for the engineering, architectural and scientific communities. The logistical complexity of building such a large machine, largely compatible with existing infrastructure at the Grenoble site, and ensuring the components required for its functioning are perfectly aligned, is unprecedented. However, the advantages when the EBS is completed will be unrivalled in the opportunities provided for the world’s researchers. It will provide the most advanced beamlines in the world for analytical experiments, with the brightest X-ray source ever achieved.

The new synchrotron will involve the dismantling of the 844m-circumference storage ring, the structure that generates the X-rays, and replacement with the new EBS lattice, which will enable the more powerful radiation to be generated. It will require the set-up of a pioneering, world-first magnet design developed at ESRF, wherein the 10,000 components must be aligned perfectly to the width of half a human hair in the tunnel. This set-up enables a tighter packing of electrons, increasing the brightness and degree of coherence of the X-rays by two orders of magnitude.

The outcome of this feat of engineering is laser-like properties for the EBS beams. The permanent magnet technology utilised in the machine also results in significantly reduced consumption of electricity. A thousand innovative magnets arranged around the EBS storage ring – nearly twice as many as in the previous storage ring – will be squeezed into the same space inside the accelerator tunnel.

Though the majority of the machine has already been assembled off-site, the removal of the original ESRF equipment and installation of EBS instrumentation is a major task, pushing science and technology to its known limits, bringing X-ray science into research domains and applications that could not have been imagined a few years ago. The aim is to have the beamlines and machine fully operational by 2020.

A brilliant future for synchrotron science

The new EBS beamlines will make it possible to examine complex materials at the atomic level in immense detail, with higher resolution, and faster than ever before. These new instruments will help scientists to address major challenges facing our society, including the development of the next generation of drugs, biomaterials and sustainable resources, and to provide deep insights into the complex mechanisms governing living organisms. They will help elucidate our recent and ancient past, as manifested in historical artefacts and fossils. What’s more, they will provide unique opportunities for applied and innovation-driven research.

EBS will be a powerful new tool for the international scientific community, bringing together researchers from all over the world, and opening the door to new experiments in X-ray science. By pushing the frontiers of accelerator technology, the EBS lattice has inspired other major light sources around the world to exceed their own known limits of science, technology and engineering.

By ESRF

Featured image credit: CANDE/ESRF