The European Synchrotron

In plain words

Imagine you want to know how a new battery material changes while it charges, or how a virus protein grips a human cell. An ordinary microscope cannot help: atoms are thousands of times smaller than the wavelength of visible light. You need light with a much shorter wavelength, and a lot of it. The ESRF is a factory for exactly that kind of light.

Scientists bring their samples to Grenoble, place them in front of an X-ray beam and record how the X-rays are scattered or absorbed. From those patterns they work out where the atoms are and how they move. The machine itself stays in Grenoble; what scientists take home is data.

What it is for

Most of the light the ESRF produces is X-rays with a wavelength of about 0.1 nanometre, roughly the size of an atom. That is what makes it useful: X-rays this short and this bright can show where atoms sit in a crystal, how a material changes under pressure or how a protein is folded.

The work done here ranges from biology, chemistry, materials science and physics to medicine, cultural heritage and quantum science. The ESRF compares its X-rays with those used in hospitals and puts them at a hundred billion times brighter or more. How the machine makes them is explained on From electron gun to beamline.

What has been studied here

The ESRF’s own examples give a sense of the range. When the upgraded source opened in 2020, the ESRF listed projects such as 3D scans of whole human organs at micrometre resolution, mapping the brain down to the level of synapses, tracking lithium atoms inside a battery as it charges, detecting tiny amounts of nanoparticles in soil and performing “virtual autopsies” of mummies without opening their sarcophagi. In April 2020 researchers were already using the new beam to study the SARS-CoV-2 virus.

Palaeontology is a long-running speciality. The ESRF dates the first fossil scans by Paul Tafforeau to 2000, when samples were one or two centimetres across; today a dedicated beamline can take objects up to 2.5 metres tall and weighing around 300 kilograms. Structural biology has always been a large part of the work, and the ESRF counts two 2009 Nobel laureates in chemistry, Ada Yonath and Venki Ramakrishnan, among its users: Ramakrishnan’s group used the facility in its work on the structure of the ribosome, the cell’s protein factory.

Who runs it

The ESRF is an international organisation supported by 19 partner countries: 13 members and 6 scientific associates. France and Germany hold the largest shares; Poland is one of the scientific associates. Poland joined on 26 April 2004, two weeks before it entered the European Union.

More than 9,000 scientists from around the world come to Grenoble each year to run experiments. The beamlines, the experimental stations around the ring, work 24 hours a day, seven days a week; the ESRF’s key figures give 44 of them. The ESRF also reports nearly 2,000 scientific publications a year based on its data, and says that 30% of its public research involves industrial participation.

A short history

The idea is older than the machine. In 1975 the physicist William Garton of Imperial College London wrote to the European Science Foundation urging European collaboration on synchrotron research; expert groups then drew up the specifications in the late 1970s. The research ministers of 11 European countries signed the ESRF Convention in Paris in 1988, creating what the ESRF calls the world’s first third-generation synchrotron. The first electron beam circulated in the storage ring in 1992, when the first users also arrived, and the facility was officially inaugurated in 1994 with 15 beamlines. By 1998 there were 40.

A first upgrade programme, from 2009 to 2015, added 19 new beamlines and a new experimental hall of 8,000 square metres. Then, in 2015, the ESRF launched the Extremely Brilliant Source (EBS), a new storage ring built inside the existing tunnel. The old ring was switched off on 10 December 2018 after 26 years of service; electrons first went round the new one on 28 November 2019, and it opened to users on 25 August 2020. The ESRF calls it the first high-energy fourth-generation synchrotron and says it made the X-ray beams 100 times better in brilliance and coherence. The project cost 150 million euros.

How scientists get beam time

For academic research, time on the beamlines is awarded through peer review. Scientists send in proposals, which are graded by review panels: there are 13 of them, each covering a group of beamlines, and each reviewer gives a mark from 0 to 5.5. Feasibility and safety are checked separately. The standard deadlines are 1 March and 10 September, and decisions follow about three months later. Demand is high: the ESRF received 792 proposals in 1995 and 2,200 in 2024.

Companies can also buy beam time. The ESRF offers them access in confidence and names sectors such as pharmaceuticals, chemistry, cosmetics, food, energy, semiconductors and metallurgy; it says more than 150 clients have used it for confidential research over five years.

Why it matters

A single synchrotron serves thousands of research groups that could never build one themselves. That is the logic of the ESRF: countries pool their money for one very large instrument and share the time on it. The same idea lies behind its neighbour, the neutron source described on Europe’s neutron source, and the two are often used together, as explained on Two ways of seeing atoms.