Go Big! ESRF – The European Synchrotron Radiation Facility
What is ESRF and who are the people that work there?
The European Synchrotron Radiation Facility (ESRF) is a state-of-the-art high-energy, 4th generation X-ray source capable of precisely probing atomic positions and electronic states in matter. X-rays provided by the ESRF are 10 trillion times brighter than laboratory or medical X-ray sources, allowing for faster measurements (down to milliseconds) with greater resolution and highly focused X-ray beams (down to nanometers). Moreover the X-ray radiation can probe trace elements at greater dilution levels (few parts per million), and study matter contained in complex or heavily absorbing matrixes, and/or at extreme conditions like those in planetary interiors (500 GPa and 6000 K). These characteristics are very advantageous for the investigation of geomaterials and therefore synchrotron X-ray radiation has become an important tool in fundamental and applied Earth sciences, as well as many other scientific disciplines.
Based in Grenoble, France, the ESRF is supported by 13 Members and 6 Scientific Associate countries, which makes it a unique place for international collaboration. The ESRF is a user facility providing support for researchers interested in using X-ray radiation for their research. Access is provided through proposals that are selected through a review process and specific panels. In this way, the ESRF ensures the success of more than 1000 experiments each year involving a combination of permanent scientists and technicians, as well as temporary staff including, trainees, PhDs, postdocs, junior and visiting scientists. At the same time, the ESRF is fostering scientific collaborations with universities through master and PhD thesis programs.
Three main X-ray probe techniques, amongst others are utilised at the ESRF: X-ray spectroscopy, diffraction and tomography. Put simply, the diffraction phenomena allows the reconstruction of the position of atoms, and thus the atomic structure of crystals, glasses or liquids by measuring the diffraction angles of photons. Spectroscopic methods in turn are highly element selective, and are used to either probe spatial and temporal concentration changes of elements (e.g., in-situ partitioning or dissolution experiments), or to probe the local atomic environment of an element of interest and its electronic structure using the X-ray absorption phenomena. Finally, X-ray tomography is used to monitor the sample’s morphology (grain boundaries, cracks, fluid or air inclusions) in 3D volumes upon variable external conditions (pressure, temperature, stress).
Spectroscopy
How is it used in geochemistry
X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF) present excellent probe techniques to study geomaterials, due to their element-selectivity, high sensitivity to concentration changes, and ability to characterize ordered and disordered structural environments. These techniques have been used widely to elucidate the valence of minor elements and their structural incorporation mechanism in synthetic and natural samples. They have also been applied to quantify concentrations of highly diluted elements in chemically complex heterogeneous samples or during reactions (e.g. partitioning, and dissolution). A wide range of elements can be studied, at ambient or extreme conditions, using optimised devices and down to very low-concentration levels (ppm); specialised detectors allow resolution of the weak signal of one trace element in very complex sample environments.
How are the samples prepared
Samples can be natural pieces of rocks of several mm mounted on a holder, powders pressed into pellets or synthetic samples. For studies under extreme conditions samples can be very small, as little as micrometer sized. Here a fluid can be analysed together with a solid phase.
How long does it take
This depends of the experiment and concentration of the element of interest, measurements can take several hours down to 1 second.
Diffraction
How is it used in geochemistry
X-ray diffraction (XRD) is a very common technique for investigating the structure (hence the phases) of materials. Thanks to synchrotron radiation, high-resolution diffractograms can be recorded, both in time (e.g., phase transitions during heating, or application of pressure, or during different gas flows), space (e.g., mapping of samples), and reciprocal space (allowing for a better identification of phases for complex systems, as the peaks are better resolved compared to standard lab XRD instruments). Different techniques are available, from simple mapping of the sample to more complex reconstruction of the phases and grain boundaries in 3D e.g., X-ray diffraction computed tomography (XRD-CT), 3D-XRD, and Dark-field X-ray microscopy (DFXM).
How are the samples prepared
The advantage of using X-ray radiation is its tunability in terms of energy. High-energy X-rays have a high penetration through matter, allowing for the measurement of “big” samples in air (e.g., a piece of rock) or in specific sample holders, especially for pressure (e.g., diamond anvils) or gas flow measurements (e.g., capillaries).
How long does it take
The acquisition time highly depends on the technique. A single diffractogram can be measured in few milliseconds, making high throughput measurements possible (hundreds of samples per hour can be screened automatically); 2D mapping of a sample can be performed in a few minutes; 3D scans can take several tens of minutes (depending on the technique and the sample size and geometry).
Tomography
How is it used in geochemistry
At the ESRF, X-ray tomography provides unprecedented insights into geochemical processes by detailed imaging of 3D volumes of rock and their time mineralisation, from a few tens of microns to submicron scales. With some limitations samples can also be imaged to a few tens of nanometers. Researchers can visualize pore networks, mineral reactions, and deformation mechanisms in situ, under simulated Earth conditions with scans spanning a fraction of a second to a few minutes depending on resolution needs.
How are the samples prepared
Samples are often prepared as cylindrical cores, and can be prepared by the users, onsite or with our facilitators. Extreme pressure and temperature can be reached using specific sample holders available at the beamlines (e.g., diamond anvil cells). With the CHRONOS project, the experiment time can extend from a few days to over a year to observe gradual geochemical changes. Whether investigating carbon sequestration, mineral trapping, or fluid-rock interactions, X-ray tomography offers an unparalleled toolset for research.
How long does it take
Depending on the sample size and the resolution required, scans can take from a fraction of a second to a few minutes.
I’m hooked…where can I learn more about synchrotrons?
There are several online resources to learn more about synchrotrons:
- https://www.my-mooc.com/fr/mooc/synchrotrons-and-x-ray-free-electron-lasers-techniques-and-applications
- https://www.wayforlight.eu/synchrotrons
- https://lightsources.org/what-is-a-light-source/
There are also training courses, such as Hercules (Higher European Research Course for Users of Large Experimental Systems). This is an annual, five-week course coordinated by the Université Grenoble Alpes. The school provides training for students, postdoctoral and senior scientists from European and non-European universities and laboratories. There is a competitive application process that opens in August each year.
Who uses ESRF? Can I apply for access?
Access is open to anyone with a compelling scientific question, whether from academia or industry. Researchers can apply for beamtime through standard proposals twice a year, which undergo peer review to allocate access based on scientific merit. For long-term studies, BAG projects (Block Allocation Group) allow collaborative teams to secure recurring beamtime over multiple cycles. For example, the CHRONOS project specifically focuses on long-term scanning needs, enabling the study of slow, dynamic processes, such as geochemical reactions over weeks or months.
The CHRONOS project at ESRF is a specialized access mode designed for long-term in situ synchrotron experiments. Its mission is to capture slow processes in real time by enabling continuous X-ray imaging over extended periods. The principle relies on automated, scheduled scans that allow researchers to track dynamic changes in materials under controlled conditions with implications for numerous scientific and industrial fields. In geosciences, it enhances our understanding of fault mechanics, fluid-rock interactions, and carbon sequestration. By bridging timescales and automating data collection, CHRONOS advances synchrotron techniques and opens new possibilities for studying time-dependent natural and manufactured systems.
What support is provided by the staff at ESRF?
Peer-reviewed proposals give access to the ESRF free of charges. Industrial experiments need to be discussed with the Business Development Office (BDO), who will also provide a quotation for the beamtime access: https://www.esrf.fr/Industry
If you are from an institution from a member country of the ESRF, you might be eligible for reimbursement of your travel, accommodation and meals for the duration of the experiments. Please check the details here: https://www.esrf.fr/UsersAndScience/UserGuide/FinancialAssistance
Which beamline is the correct one for me?
Are you wondering which beamline might be suitable for your specific question and/or project. Visit the “Find a Beamline” page on the ESRF website where you will find descriptions of each of the 46 beamlines, also information on the different research groups, and a beamline search tool: https://www.esrf.fr/home/UsersAndScience/find-a-beamline.html
Is there a central contact office?
If you want to submit a proposal, you are strongly encouraged to contact the beamline staff in advance to obtain specific information about the beamline, the feasibility of the measurement, and support in the proposal writing.
Central enquiries: https://www.esrf.fr/UsersAndScience/UserGuide/Contacts
Contact information for individual beamline scientists can be found on the webpages of their respective beamlines.
Contribution by Marta Mirolo and Benoit Cordonnier, with the support of Angelika Rosa, Ilya Kupenko, and Marco Di Michiel. Edited by the EAG Communications Committee.