Category: ESRF

The Long Read: All in a spin

The Long Read: All in a spin

As 2025 marks the International Year of Quantum Technology, the ESRF contributes to the global exploration of quantum phenomena by delving into the mysteries of novel quantum magnets. These materials offer a fascinating window into the fundamental interactions of matter, yet their behaviour remains highly mysterious. To unravel them, ESRF users have had to push the boundaries of an X-ray technique. This article was first published in the March 2025 issue of the ESRFnews magazine, dedicated to quantum technology.

It is one of the most famous experiments in physics. Light illuminates a pair of slits in a wall, generating an array of bright and dark patches on a screen. The British physicist Thomas Young first performed the experiment at the turn of the 19th century to demonstrate that light can interfere with itself, behaving as a wave. Much later, quantum versions of the experiment would demonstrate something far more mysterious: that photons, electrons and other particles can exhibit wave-like interference patterns, but apparently only when no-one is watching. The experiment “has in it the heart of quantum mechanics”, wrote the American physicist and Nobel laureate Richard Feynman. “In reality, it contains the only mystery.”

Today, few scientists doubt the merits of quantum mechanics. It has proved itself through mind-boggling predictive power, not to mention a host of practical applications: semiconductor electronics, lasers, superconducting magnets, quantum cryptography and quantum computing, to name but a few. Yet it is still a subject ripe with puzzles, both in its basic interpretation and in its role in condensed matter, where each material can serve as a quantum playground.

One puzzle is the existence of peculiar types of magnetism, as studied by ESRF users such as Markus Grüninger from the University of Cologne in Germany. Unravelling these phenomena has led Grüninger and his colleagues to shift the boundaries of an X-ray technique – amazingly, in such a way as to recall Young’s famous experiment once again. “Our experiments rely on the excellent beam quality at the ESRF, the outstanding performance of the set-up at beamline ID20, and the fruitful collaboration with the beamline staff,” says Grüninger.

The technique in question is resonant inelastic X-ray scattering (RIXS). This begins with an X-ray photon knocking a tightly bound electron up to a higher atomic energy level. Almost instantaneously an electron from another high energy level relaxes into the resultant hole, releasing a new photon. By measuring the difference in energy between the incoming and outgoing photons, users can learn how the process has changed the solid in collective excitations of electron charge and spin – the latter being the basis of magnetism. The ESRF has helped develop RIXS since the 1990s, and currently offers it at two dedicated, world-leading beamlines: ID32 with soft X-rays, and ID20 with hard X-rays.

Hard X-ray photons can transfer a lot of momentum to a sample. In 2019, an international team led by Grüninger wanted to push ID20’s capabilities, and record an even greater range of momentum transfer than usual. Drawing on theory by Jeroen van den Brink at IFW Dresden in Germany, and making use of new ID20 instrumentation developed by beamline scientists Giulio Monaco (now at the University of Padova in Italy) and Marco Moretti (now at the Polytechnic University of Milan, also in Italy), the team studied the effect of large changes in momentum transfer on the intensity of the outgoing X-rays. Their sample was a crystal of an iridium oxide containing pairs or “dimers” of iridium ions. To their delight, the researchers found an interference pattern, demonstrating that the X-ray photons were exciting electrons at both iridium sites in the dimers at once – similar to light passing through Young’s double-slit, although in this case putting the dimer in an excited state

The experiment marked the beginning of RIXS interferometry, a technique that was predicted as far back as the mid 1990s. By demonstrating that the electrons in the iridium dimers experience a quantum, wave-like delocalization over a quasi-molecular dimer orbital, RIXS interferometry opened the door to the study of materials with novel magnetic properties, which physicists have been trying to understand for decades.

The most familiar type of magnetism – the sort that exists in a common fridge magnet – is ferromagnetism. In metals such as iron, it results from conduction electrons that are delocalized over an entire crystal, with spins able to align parallel to one another, producing a net magnetic moment. This is very different to one type of material with novel magnetism, the Mott insulator. Conduction in this type of material is forbidden due to strong electron repulsion, but it still has magnetism because its spins, while localized on individual ions, can interact with each other. Even more intriguing is the cluster Mott insulator, an emerging new class of material that exhibits what could be called a “local delocalization”. Here, electrons are fully delocalized over a dimer (or another small collection of ions), but they cannot propagate from one dimer to another. This results in local magnetic moments, residing not on individual ions but on quasi-molecular clusters. “In contrast to the usual electron spin, these cluster moments are something that we can tailor, by choosing the ionic species, cluster geometry, electron count, pressure and so on,” says Grüninger.

In 2022, Grüninger and colleagues used their new RIXS interferometry to unambiguously identify a cluster Mott insulator for the first time. The ID20 data could directly reveal the presence of three electron spins delocalized over an iridium dimer, creating a cluster magnetic moment [2] in a compound that is a candidate for a quantum spin liquid. The data also paved the way for a systematic exploration of more complex compounds, for example with trimers [3] or tetramers, rather than dimers. “Our results show that the trimers reside in an unexpected parameter regime that promises non-trivial magnetic moments,” says Grüninger. “They challenge previous views on trimer physics, highlighting the strength of RIXS interferometry.”

Cluster Mott insulators are exciting because of their potential as microscopic, fine-tuned magnets, as well as for their still-unexplored quantum properties. They also have potential to realize quantum “spin liquids”. First predicted by the US physicist and Nobel laureate Philip Anderson back in the 1970s, though experimentally elusive, spin liquids excel by the quantum-driven absence of magnetic order – even at temperatures close to absolute zero – that defines more conventional magnets. They are characterized by a quantum-entangled network of strongly fluctuating spins, driven by competing interactions that cannot be satisfied simultaneously. A simplified example of the situation is three spins on the vertices of a triangle: they may all want to align antiparallel to each other, but this is possible only for a pair of them, not all three simultaneously.   

Read more on ESRF website

A highly stable and effective gold complex proves promising for anticancer treatment

A highly stable and effective gold complex proves promising for anticancer treatment

Chemists have discovered a highly stable gold complex in both model conditions and intracellular environment that triggers mitochondrial damages and hence could be used as an anticancer treatment. They came to the ESRF to characterize the complex on two beamlines. The results are out in Angewandte Chemie International Edition.

In ancient medicine, gold was used in Chinese medicine to treat various ailments. The Egyptians ingested gold for purification, while medieval alchemists sought its elixir for longevity. In the 20th century, gold compounds were developed to treat rheumatoid arthritis, marking transition into modern medicine.

 “The discovery of medicinal properties of platinum complexes has led to the development of novel anticancer metallodrugs with unique mechanisms of action, but toxic side effects and drug resistance from the body are pushing us to study other candidates, and in our case we focus on the design of ‘organogold’ complexes”, explains Hester Blommaert, researcher on beamline BM16 and first author of the publication.

The team, from the Sorbonne University, The Université Grenoble Alpes, the CNRS, the INSERM and the ESRF, has explored seven different gold compounds and used different synchrotron techniques at the ESRF to map how the gold compounds interact with cells. “This is a multidisciplinary team, including chemists, physicists, engineers and biologists”, says Jean-Louis Hazemann, group leader of the FAME-UHD BM16 beamline.

Toxic at low concentrations

“First, the team in Sorbonne University designed and synthesized the gold molecules and found that one of these compounds was very toxic towards cancer cells at low concentration, which is very promising”, explains Olivier Proux, scientist in charge of BM16.

At the ESRF, they used cryo-X-ray fluorescence microscopy on ID16A to pinpoint the precise intracellular location and quantity of gold in whole cells, without any sectioning and without the need for fluorescent dyes, and X-ray absorption spectroscopy on BM16 to gather information about the oxidation state and molecular transformations of gold within the cells. In particular, on BM16 they could solve spectra with a very high resolution for very low concentrations of gold, which is biologically relevant.

Sylvain Bohic, researcher at INSERM and part of the team, explains how the ESRF techniques allowed them to acquire their results: “We aimed to understand the compound’s mechanism of action at the subcellular level and assess its stability under biologically real-life conditions. While these compounds hold great potential against cancer, they cannot advance in drug development without a comprehensive understanding of their behavior within tumor cells, which is crucial for advancing novel chemotherapies. The application of these cutting-edge sensitive synchrotron techniques provided at ESRF is a critical first step toward achieving this goal”.

Read more on ESRF website

A new 100 picosecond time-resolved technique images surface acoustic wave devices

A new 100 picosecond time-resolved technique images surface acoustic wave devices

Beamline ID01 can now study Surface Acoustic Waves (SAW) devices at operando conditions thanks to a new technique called stroboscopic full-field diffraction X-ray microscopy at the ESRF. Their results open the doors to more experiments with these systems and on electronic circuits and devices in general. They are published in Nature Communications.

A Surface Acoustic Wave (SAW) device is an electronic device that uses sound waves traveling along the surface of a material (usually a piezoelectric crystal) to process, filter or transmit signals. Their applications are wide, and include mobile phones, Wi-Fi, GPS, and 5G networks to filter and separate different frequency bands, touchscreens, sensors in the automotive and aviation industry, biosensors. They are also promising devices in nanoscale applications, such as quantum communication.

Because they are highly sensitive, durable, compact and cheap, there is a lot of ongoing research into understanding how to optimise their structure. This needs a deep understanding of energy conversion and loss mechanisms taking place in the device.

In SAW devices, electrical energy is converted into sound waves using interdigital transducers. These are tiny comb-shaped metal electrodes placed on a piezoelectric crystal. One set of electrodes is grounded, while the other receives an alternating voltage, causing the crystal’s surface to strain or deform. This vibration creates an acoustic wave that travels at several kilometers per second. These waves have extremely high frequencies (hundreds of MHz to GHz), far too fast for even the best high-speed cameras to capture.

However, now a team led by ESRF scientists has developed a technique called stroboscopic full-field diffraction x-ray microscopy on beamline ID01, which allows them to study the dynamic strain in SAW devices. “Today the spatial resolution at the ESRF’s ID01 is about 100nm and we have a time resolution in the storage ring of 100 picoseconds: this is practically the speed of sound . This means that we can image sound unblurred”, explains Tobias Schulli, scientist in charge of ID01 and co-corresponding author of the publication.

The experiments showed that there was an unexpected acoustic loss in a resonator device tested. It proved that propagating modes leak elastic energy away from the resonator. The high sensitivity of X-ray diffraction for changes in atomic distances by 1/100 000 together with the high time and spatial resolution available on ID01 represent the only available technique to detect and quantify such phenomena.

Read more on ESRF website

Scientists find ways to reduce oil intake in deep fried foods

Scientists find ways to reduce oil intake in deep fried foods

A new 4D imaging system has tracked the process of frying foods at the ESRF, in a quest to make the products absorb less oil and therefore, healthier. Their insights show that it is especially after frying, during the cooling process, that food absorbs oil, and that the amount of oil absorbed depends on the porous structure created during frying. The results are out in Nature Communications.

Fried foods are staple especially in Western diets due to their distinct flavour and sensory characteristics. The frying process causes foods to develop unique textures related to their crispy outside and soft inside.

“People like fried products because of the texture and the taste, but they have been claimed to be an ultra-processed food that we should try to minimise in our diet”, explains Pieter Verboven of KU Leuven in Belgium, corresponding author of the publication. “Still, the final composition is more of a concern than the process itself”, he adds. Therefore, the KU Leuven research team are investigating ways to reduce oil content but preserve texture and taste.

When we fry food, we submerge it into hot oil that is more than 160 °C. This leads to very fast evaporation of water and creates internal pressure in the form of steam, which results in an expanding porous structure. “This process is extremely fast, in the order of seconds, and we don’t have the tools to see what happens in real-time, so we need to come to the ESRF to be able to track the process”, says Verboven.

A fryer on the beamline

The team came to ID19 to carry out high-speed 4D computed tomography on wheat flour dough, a common food material subjected to deep-frying. The experiments took place as the dough was frying in a custom oil fryer and afterwards, during the post-frying cooling, with the aim of investigating the structural deformation and pore formation, as well as oil uptake. “The experiment was extremely complex, as we needed to scan the sample submerged in oil very fast to track all the changes at the microstructural level”, explains Bratislav Lukic, researcher at the ESRF and co-author of the publication, “The fryer was also equipped with sensors and actuators to precisely control the process remotely. Thanks to high flux at high energy of the Extremely Brilliant Source, we were able to reach sub-second scanning times while maintaining microscopic spatial resolution, all that in a very large fryer, which is representative of the process.”

They visualised how the product expands due to steam during the frying process, which hinders the oil from getting inside. At the same time, the physico-chemical changes in starch and gluten structure determine the pore structure. The trick is to control this process well to create the desired texture with a crispy crust and fluffy interior. The team found that oil is absorbed mostly during the cooling of the fried dough and, in smaller percentage, during the frying process itself.

Read more on ESRF website

The gut-brain connection in Alzheimer’s unveiled with X-rays

The gut-brain connection in Alzheimer’s unveiled with X-rays

Scientists led by the Institute of Nanotechnology in Italy, in collaboration with the ESRF, have discovered how X-ray micro- and nano- tomography can provide clues on the processes that link the gut neurons with those in the brain and may trigger Alzheimer’s. The results are out today in Science Advances.

Alzheimer’s disease, the most common type of dementia, is a neurodegenerative disorder characterized by brain alteration including synaptic loss, chronic inflammation and neuronal cell death.

In recent years, scientists have found evidence that the gut and the brain communicate through the neurons placed in both organs. Dysfunction in this axis has been linked to psychiatric and neurological disorders, including Alzheimer’s.

The gut microbiota, which refers to the microorganisms in the intestinal tract, plays a key role in human health and influences brain function, cognition and behaviour. “There are already many studies that support that changes in the gut composition can contribute to Alzheimer’s onset and progression”, explains Alessia Cedola, researcher from the Institute of Nanotechnology in Italy and corresponding author of the article.

In particular, dysbiosis, which is the process by which there is a loss of microbial diversity, induces the prevalence of dangerous bacteria producing toxic metabolites promoting inflammation, and, consequently, the breakage of the gut/brain barriers.

What happens exactly when gut dysbiosis occurs? “The main hypothesis is that changes trigger the escape of bad bacteria from the gut, entering the circulation, reaching the brain and triggering Alzheimer’s, but evidence is still poor”, adds Cedola.

Now scientists have discovered that nano- and micro X-ray phase-contrast tomography (XPCT) is a powerful tool to study structural and morphological alterations in the gut, without tissue manipulation. The team came to the ESRF to scan samples on beamline ID16A. “Thanks to this technique we can image soft biological tissues with excellent sensitivity in 3D, with minimal sample preparation and without contrast agents”, explains Peter Cloetens, scientist in charge of ID16A and co-author of the publication.

The data of the experiments, partially carried out at ANATOMIX at Soleil, showed the changes in cell abundance and organisation in the tissues, as well as structural alteration in different tissues of mice affected with Alzheimer’s. Specifically, it showed relevant alterations in the villi and crypts of the gut, cellular transformations in Paneth and goblet cells, along with the detection of telocytes, neurons, erythrocytes, and mucus secretion by goblet cells within the gut cavity. All these elements, when working correctly, maintain gut health, support digestion, and protect the intestinal lining from damage.

Read more on ESRF website

Image: Nano-XPCT 3D rendering of the longitudinal view of one crypt of SAMR1 mouse. The epithelial layer of the crypt has been rendered in green. The Paneth cells are colored in yellow and the goblet cells in blue. Scale bars, 5 μm.

Credit: A. Cedola

Scientists visualise crucial step in protein production in bacteria

Scientists visualise crucial step in protein production in bacteria

Researchers have visualized for the first time how mRNA is delivered to the ribosome to begin production of proteins. They solved 9 of the structures using the ESRF’s cryo-EM. The results are published in Science.

Our DNA holds the instructions for making proteins, which are essential for the body to function. To use these instructions, a molecular machine called RNA polymerase (RNAP) copies the relevant section of DNA into a short-lived copy called messenger RNA (mRNA). This mRNA carries the instructions to another molecular machine, the ribosome. In bacteria, these two steps happen at the same time, allowing RNAP and the ribosome to cooperate and regulate each other.

A team led by Albert Weixlbaumer at the  Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) in Strasbourg, France, wanted to know how bacterial ribosomes are recruited to mRNAs, while they are still transcribed by RNAP. Using cryo-electron microscopy (cryo-EM), they studied complexes where an mRNA emerging from RNA polymerase (RNAP) was bound to the ribosome’s small subunit.

The team used cryo-EM at the ESRF and at IGBMC to visualize the ribosome-mRNA assemblies at molecular resolution. This enabled them to observe the process in great detail. The cryo-EM experiments at the ESRF provided the structure of 9 of the complexes studied. “Access to high-end cryo-EM instruments is absolutely essential and represents the culmination of our work. It is a real pleasure to work with the scientists at the ESRF, we always feel they are very dedicated to the projects they support and the data quality and amount of date we obtain could not be better”, explains Albert Weixlbaumer, leader of the team and researcher at the IGBMC.

Complementary single-molecule fluorescence co-localization experiments carried out in the lab of Nils Walter (University of Michigan, USA) and in vivo crosslinking followed by mass spectrometry carried out in the lab of Juri Rappsilber (Technical University Berlin, Germany) suggest RNAP and the ribosome cooperate to facilitate recruitment of the small ribosomal subunit to the mRNA.

Intricate machines

“Our research reveals how these molecules work like intricate machines. I am always amazed that it is possible to reconstitute such an intricate and biologically fundamental process in a tube in the laboratory,” says Michael Webster, now a group leader at the John Innes Centre in the UK and one of the lead authors of the study which was published in Science.

“It is particularly exciting to have the opportunity to use powerful imaging techniques to answer questions that researchers have been interested in for a long time,” he adds.

Read more on ESRF website

High-Power Laser Facility probes iron at the Earth’s core conditions

High-Power Laser Facility probes iron at the Earth’s core conditions

probe

Scientists have captured unprecedented detail of how iron behaves under extreme conditions approaching those of the core – advancing our understanding of planetary dynamics. Published in Physical Review Letters, these are the first experimental results from the new High-Power Laser Facility (HPLF) at the ESRF.

At the heart of our planet, Earth’s core comprises two distinct sections: a molten outer core that begins around 2,900 km beneath our feet, and a solid inner core starting around 5,150 km. Iron accounts for roughly 85% of the core by weight, combining with nickel and lighter elements to form alloys.

But uncertainties remain over the melting point of iron and its alloys under the extreme pressures of deep Earth. Debates also persist over how iron’s crystal structure may change with depth, which influences its physical and chemical properties at larger scales.

Shocked to the core

Fresh insights into these questions are revealed in new experimental work by Sofia Balugani, PhD student at the ESRF within the InnovaXN programme, in collaboration with the Ecole Polytechnique (LULI Laboratory, France), the First Light Fusion company (UK), and the HPLF team. The researchers “shocked” a tiny iron target (3.5 μm-thick) by firing it with a laser pulse, reaching a pressure of 240 GPa. By coupling the laser with X-rays, they recorded a bulk temperature measurement of 5,340K, the first of its kind for iron’s melting plateau under such extreme conditions. A melting point of 6200K was extrapolated for the even higher pressures of the inner core boundary (ICB).

“After three years of PhD research, this work fulfills my long-standing interest in planets, allowing me to study materials crucial to planets and their properties under extreme conditions, such as those on Earth,” says Balugani.

The research helps refine models of the Earth’s core’s behaviour. That’s because HPLF is optimised for this type of X-ray absorption experiment, which enabled the team to simultaneously track temperature alongside changes in the local order of iron. The findings rule out a transition in iron’s lattice structure to a high-temperature bcc (body-centred cubic) phase, which is observed in some other metals under shock compression such as copper and gold.

Instead, iron remains in the denser hcp (hexagonal close-packed) phase. The results may interest astrophysicists searching for exoplanets, given the importance of the core in generating a geomagnetic field and driving plate tectonics – both of which are key to supporting habitable conditions on Earth.

Read more on ESRF website

Image: The High-Power Laser Facility at the ESRF.

Credit: S. Candé.

Room-temperature serial crystallography experiments with microsecond pulsed beams

Room-temperature serial crystallography experiments with microsecond pulsed beams

Scientists can now scan thousands of protein crystals at room temperature using X-ray microsecond pulses at the ESRF’s serial crystallography beamline, ID29. This capability is of utmost importance for time-resolved studies and drug discovery research at physiological conditions. The results are published in Communications Chemistry.

Studying macromolecular complexes at room temperature has always been challenging because of X-ray damage to the biological samples. Usually this is mitigated by collecting diffraction data at cryogenic conditions, but under these conditions functional dynamics are hindered.

Serial crystallography can provide an alternative way to collect data at physiological conditions with limited X-ray damage andto visualise functional dynamics that become untrapped. Serial femtosecond crystallography at X-ray free electron lasers (XFELs) allow scientists to decode macromolecular structures by acquiring data of tiny protein crystals at room temperature, outrunning the damage thanks to the extremely short pulses on the femtosecond. The transfer of the same technology to 3rd generation synchrotrons has been often limited to longer exposure time, flux and spatial resolution.

At the ESRF, thanks to the Extremely Brilliant Source, the ID29 beamline today has a flux density of ( > 1014 ph/s/µm2), three times higher than 3rd generation synchrotron sources. With this, scientists can deliver X-rays in very short pulses, on the microsecond time resolution, and at a very high repetition rate for macromolecular structure determination at room temperature.

Combined with a slightly polychromatic beam, this allows to measure complete reflections and ultimately accurate structure factor from thousands of microcrystals, even from low redundant datasets. This combination minimizes the sample consumption down to only a few microliters of crystal slurry, in contrast to larger amounts that are frequently needed for serial experiments, and allows complete data to be collected in the fraction of the time.

“Our beamline is the first in the world at a high energy 4th generation synchrotron which is designed to use the high flux density to study macromolecules at room temperature, with a microsecond time resolution”, explains Daniele de Sanctis, scientist in charge of ID29 together with Shibom Basu, EMBL scientist. “The technique, called serial microsecond crystallography (SµX), allows researchers to use less sample to achieve comprehensive structural detail of proteins under physiological conditions and also to visualise molecular movies in action on this time domain. Our work initiates a new future of time-resolved serial microsecond crystallography experiments at 4th generation storage rings, that will ultimately complement X-ray free electron laser (XFEL) experiments.”

A versatile sample environment

One specificity of serial crystallography is the set-up. How do scientists deliver a slurry of hundreds to thousands of microcrystals to the beam? This is a constantly evolving field and ID29 can accommodate different kinds of sample delivery methods with its flexible setup. The researchers applied the unique beam of ID29 to different sample delivery methods: fixed target (foils and chips) and  three different types of high viscosity extruders demonstrating how structures obtained do not present any evident sign of radiation damage. The data quality obtained allows to unambiguously identify the electron density map of ligated molecules.

Read more on ESRF website

Image: Daniele De Sanctis, scientist in charge of the ESRF, and Shibom Basu, from the EMBL, on the beamline.

Credit: S. Candé.

Thin ceramics make strong piezoelectrics

Thin ceramics make strong piezoelectrics

Scientists from India and Australia have shown how to boost the electro-mechanical response of piezoelectrics made from ceramics. Published in Nature, their work reveals that the thinness of the ceramics is key to bringing the performance in line with expensive single-crystal ferroelectrics.

Piezoelectrics are materials that deform in response to an electric field. They are important in all sorts of industrial and consumer devices, typically acting as sensors, fine actuators and sound generators. Generally speaking, the bigger the piezoelectric response, the better.

Some of the biggest responses are found in ferroelectrics – that is, materials with a permanent electric polarization – in single crystal form, but these take a lot of time and energy to synthesise. On the other hand, ceramics can easily be processed on a large scale. These are brittle materials composed of many crystal grains, but usually they have less than two-fifths of the piezoelectric response of their counterparts made of single-crystal ferroelectrics.

Groups led by Rajeev Ranjan at the Indian Institute of Science in Bangalore, and John Daniels at the University of New South Wales in Sydney, have been investigating whether the piezoelectric response in ceramics might be limited by the “clamping” of individual crystal grains by their neighbours. If so, then a thinner ceramic ought to perform better, as a bigger portion of its grains would be at the material’s surfaces, where there are fewer neighbouring grains constraining it and therefore, theoretically, more freedom. “What we didn’t know is how deep from the surface the grains can still feel relatively free,” says Ranjan.

To answer that question, they had to come to the ID15A beamline at the ESRF. Here, armed with discs 0.2 to 1 mm thick of a range of ceramic compositions, they could perform high-energy X-ray diffraction to chart the movement of grains at variable depth as they applied an electric field and measured the subsequent deformation, in situ. Observing these dynamics at micron resolution relied on the quality of the focusing optics and the mechanical sample positioning. “High energy x-rays with a planar beam geometry of about 1 x 100 µm2 were necessary to have the depth resolution and sufficient grain sampling. The source and optics of ID15A allowed this unique combination,” says Daniels.

To the researchers’ surprise, the crystal grains were relatively free even 0.1 mm below the surface.  This explained why the discs that were just 0.2 mm thick deformed by as much as 1% in that axis – a threefold improvement on 0.7 mm discs, and comparable to deformations found in expensive single-crystal ferroelectrics. “This is a revelation in the piezoceramic community,” says Ranjan.

Read more on ESRF website

New detoxification pathway for mercury in penguins

New detoxification pathway for mercury in penguins

An international team of scientists led by the ESRF has found that emperor penguins detoxify mercury with both sulphur and selenium, a new pathway for a marine predator. This new detoxification pathway for mercury has been unveiled in a study published in the Journal of Hazardous Materials.

Mercury is considered by WHO as one of the top ten chemicals of major public health concern. Mercury bioaccumulates in organisms along time and biomagnifies in aquatic and terrestrial food webs as the neurotoxic form of methylmercury. Understanding the internal detoxification processes of methylmercury in animals is essential for protecting wildlife and designing treatments against mercury poisoning.

Alain Manceau, ESRF scientist and researcher emeritus at the CNRS, together with his collaborators from the University of La Rochelle and the CNRS (LIENSs and CEBC), the United States Geological Survey, and the University of California Davis, has been studying how animals detoxify mercury for years.

Back in 2021, they unveiled that apex predators, such as seabirds like giant petrels, and marine mammals like pilot whales, detoxify methylmercury through a sequence of reactions involving reduced selenium in the form of a prominent selenoprotein. Since mercury is ultimately detoxified as nontoxic mercury selenide, it has diminished toxicological consequences as long as there is sufficient selenium, because mercury selenide is chemically inert.

“We knew the mechanism that animals that are exposed to large quantities of mercury use; now we wanted to find out what happens with animals that are lower in the food chain, such as penguins”, Manceau explains. Emperor penguins feed mostly on Antarctic silver fish and squid, which contain methylmercury, albeit not in large quantities. Because of this, penguins are less contaminated with mercury than toothed whales, giant petrels, and other predators higher in the food web.

The scientists, who used X-ray absorption spectroscopy, identified, for the first time, a second demethylation pathway of toxic methylmercury. In Emperor penguins, the toxic mercury is partially detoxified using the same chemical pathway as giant petrels, but theses penguins have also developed a second mechanism whereby their body forms a Hg-dithiolate complex. This complex binds to cysteine amino acids in enzymes, altering their function. This demethylation pathway had never been observed before in animals, only in bacteria.  

Read more on ESRF website

Image: A baby penguin.

Credit: Yves Cherel. 

Scientists visualise the paths controlling heart performance

Scientists visualise the paths controlling heart performance

Scientists have found the role of two proteins in the functioning of the heart. The results could help better design targeted strategies to treat certain cardiomyopathies. The results are out in PNAS.

The heart works using tiny muscle filaments, and two main steps control how they interact: first calcium signals cause changes in the thin filament (actin), allowing it to connect with myosin motors. Then myosin motors on the thick filament switch from “off” (inactive) to “on” (active), so they can pull on actin and create force and shortening. The thick filament can sense how much force is needed and adjust how many motors to turn on, but scientists are still figuring out exactly how this works.

Cardiomyopathies take place when these mechanisms regulating the contraction-relaxation cycle of the heart malfunction. This is due to mutations in the contractile proteins (myosin and actin) but also in accessory proteins (Myosin-binding protein-C and titin). Broadly, MyBP-C and titin ensure together that the heart contracts effectively while maintaining responsiveness to changes in demand.

A team from the University of Firenze (Italy) used small-angle X-ray diffraction at the ESRF’s ID02 beamline back in 2017 and showed that, during muscle contraction, myosin motors move outward from the thick filament, enabling interaction with actin based on the load, which in the cardiac ventricle is the arterial pressure against which blood must be pumped (Reconditi et al. PNAS 2017). Evidence from other laboratories also suggested that thick filament activation is modulated by regulatory domains in the myosin motor itself and by accessory proteins like MyBP-C and titin. However, their specific function in cardiac performance was not known in detail.

Now the same team has found the role that MyBP-C and titin play in the functioning of the heart, at beamline ID02. “The beamline ID02 is ideal thanks to its camera length, so we can have the detector closer or further to the samples in a range from 0.5 to 31 m. This lets us explore the contractile proteins as well as the sarcomere, the unit cell of muscle, which is crucial for our research”, says Massimo Reconditi, scientist at the University of Firenze and corresponding author of the paper. “With EBS, thanks to its low divergence, we can observe on the same diffraction pattern a high number of reflections together with their fine structure”, he adds. 

Read more on ESRF website

Image: Theyencheri Narayanan, scientist in charge of ID02, on the beamline.

Credit: S. Candé. 

Scientists reveal pore formation dynamics in copper laser welding

Scientists reveal pore formation dynamics in copper laser welding

Scientists from academia and industry have identified four ways in which pores form in copper laser welding, thanks to in-situ X-ray imaging experiments at the ESRF combined with multi-physics simulation. The results provide clues for optimisation of the manufacturing of copper components through this method. The results are out in the International Journal of Machine Tools and Manufacture.

Copper is widely used for components in electric vehicles, energy storage or electronic devices because of it is excellent electrical and thermal conductivity. However, these same properties—high thermal conductivity and low infrared light absorption—pose challenges for traditional welding techniques, often leading to inconsistent results or defects.

The technique of laser beam welding overcomes some of these difficulties by delivering high-intensity, focused energy that rapidly heats and melts copper, enabling deep, narrow welds with minimal heat-affected zones. Its high processing speed and ability to be finely tuned for different material thicknesses and conditions make it ideal for modern manufacturing demands.

However, defects such as pores still happen, especially microscopic pores. Now scientists led by Technische Universität Ilmenau and TU Wien, and with the collaboration of the company COHERENT, leader in laser solutions and photonics technologies, and the ESRF, have unveiled the dynamics behind pore formation.

The findings show that pore formation is driven by four different mechanisms: bulging, spiking, upwelling waves at the keyhole rear wall and melt pool ejections. In particular, bulging takes place at the rear keyhole wall due to dynamic melt flow; spiking occurs when rapid keyhole penetration causes detachment and solidification at the tip; pores travel due to chaotic vapor flows and bulges in the melt pool and finally, depression pores are linked to melt pool ejection and dynamic keyhole pressure.

A special laser beam shape, called a concentric core-ring profile, was also analysed and found to help make the welding process more stable and reduce defects like pores.

The team used high-speed synchrotron X-ray imaging at beamline ID19, where they acquired 20,000 images per second to identify the processes in pore formation during laser beam welding.

The experiment was very challenging, with 12 engineers to install the laser welding instrument, which contained two lasers and an ESRF in-house developed gas nozzle. Alexander Rack, scientist in charge of the beamline ID19, explains the complexity of the set-up: “This is among the most demanding experiments done so far: we had to install dedicated power lines to feed the big laser needed for welding. Experiments with sample environments are core expertise of ESRF, and thanks to our experience with complex set-ups such as furnaces, gas launchers or high-pressure cells; we are perfectly adapted for this study”. He adds: “The white undulator light with the new EBS is bright enough to shine light through 3 mm of steel while welding, and we were able to take high-speed X-ray movies with microseconds exposure time”.

They then compared these results with multi-physics modeling simulations. This physics-based model, closely aligned with experimental data, allows researchers to validate elusive phenomena with unprecedented accuracy.

Read more on ESRF website

Image: Leander Schmidt, from Technische Universität Ilmenau, during the experiment on ID19.

Credit: S. Candé.

The secrets of fossil teeth

The secrets of fossil teeth

Compared to the great apes, humans have an exceptionally long childhood, during which parents, grandparents and other adults contribute to their physical and cognitive development. This is a key developmental period for acquiring all the cognitive skills needed in the complex social environment of a human group. The current consensus is that the very long growth of modern humans has evolved as a consequence of the increase in brain volume, since such an organ requires significant energy resources to grow.

However, the ‘big brain – long childhood’ hypothesis may need to be revised, as shown by an international team of researchers in the journal Nature, based on an analysis of the dental growth of an exceptional fossil.

The research team, made up of scientists from the University of Zurich (Switzerland), the ESRF and the Georgian National Museum (Georgia), used synchrotron imaging to study the dental development of a near-adult fossil of early Homo from the Dmanisi site in Georgia, dated to around 1.77 million years ago.

Teeth are the key

“Childhood and cognition do not fossilise, so we have to rely on indirect information. Teeth are ideal because they fossilise well and produce daily rings, in the same way that trees produce annual rings, which record their development”, explains Christoph Zollikofer from the University of Zurich and first author of the publication. “Dental development is strongly correlated with the development of the rest of the body, including brain development. Access to the details of a fossil hominid’s dental growth therefore provides a great deal of information about its general growth”, adds Paul Tafforeau, scientist at the ESRF and co- author of the study.

18 years of research

The project was launched in 2005, following the initial success of non-destructive analyses of dental microstructures using phase contrast synchrotron tomography at the ESRF. This technique enabled scientists to create virtual microscopic slices through the teeth of this fossil. The exceptional quality of preservation of the growth structures in this specimen has made it possible to reconstruct all the phases of its dental growth, from birth to death, with unprecedented precision. In a way, the scientists have virtually regrown the teeth of this hominid.

This project took almost 18 years from its initial conception in 2005 to the finalisation of the results in 2023. The scientists scanned the teeth for the first time in 2006, and the first results on the fossil’s age at death were obtained in 2007. “We expected to find either dental development typical of early hominids, close to that of the great apes, or dental development close to that of modern humans. When we obtained the first results, we couldn’t believe what we saw, because it was something different that implied faster molar crown growth than in any other fossil hominin or living great ape”, explains Paul Tafforeau.

Over the following few years, five series of experiments and four complete analyses using different approaches were carried out as technical advances were made in dental synchrotron imaging. With the results all pointing in the same direction, and potentially having a strong impact on the ‘big brain – long childhood’ hypothesis, the scientists had to think outside the box to understand this fossil. “It’s been a slow maturation, both technically and intellectually, to finally arrive at the hypothesis we are publishing today”

Read more on ESRF website

A new extinct species of coelacanth discovered thanks to the ESRF

A new extinct species of coelacanth discovered thanks to the ESRF

Scientists from the Natural History Museum (MHNG) and the University of Geneva (UNIGE) have discovered a new species of coelacanth, a fish considered to be a living fossil that only had two species known until now. This finding was possible thanks to the experiments done at the ESRF. The work is out in the journal PlosOne.

Fossilisation is a process that allows the preservation of plants and animals in rocks for
hundreds of millions of years. During this period, geological upheavals often deteriorate
fossils and paleontologists put great deal of effort and imagination into reconstructing
organisms as they were when they were alive.

A team of paleontologists from the MHNG and UNIGE, in collaboration with researchers from the Senckenberg Research Institute, Natural History Museum in Frankfurt am Main (Germany) and the ESRF, have just published a paper that shows the discovery of some 240-million-year-old coelacanth fossils, which show extremely detailed characteristics of of their preserved skeleton that had never been observed before.

Coelacanths are fish of which there are only two current species and which, with a few
exceptions, evolved slowly over more than 400 million years. The fossils studied by
the international team were discovered in clay nodules from the Middle Triassic period in Lorraine (France), near Saverne. The specimens, about fifteen centimetres long, are
preserved in three dimensions.

Some specimens were analysed at the ESRF in Grenoble. After hundreds of hours of work consisting of virtually individualising the bones of the skeleton by computer, the team obtained virtual 3D models of the fossils that can be easily studied. 

The results enabled the team to reconstruct the skeleton of these fish with a level of detail never obtained before for this type of fossil.

Read more on ESRF website

Trapping and storing carbon dioxide underground

Trapping and storing carbon dioxide underground

A team led by the University of Oslo in Norway, in collaboration with the University of Maryland in USA, is investigating how to massively store carbon dioxide (CO2) underground by copying nature. Through a chemical reaction, carbon dioxide can be trapped naturally inside the Earth’s subsurface and stored as solid minerals, called carbonates. The researchers are now carrying out experiments at the ESRF with the aim to accelerate such a process.

Carbon dioxide levels in the atmosphere are higher than ever, mainly due to the burning of fossil fuels and other anthropogenic activities. This, in turn, increases global temperatures and impacts sea levels and the ocean ecosystems.

A potential solution to this crisis would be to trap and store CO2 underground as solid minerals, which is a natural process that occurs over long periods thanks to the reaction of CO2 with rocks in the Earth’s crust and mantle.

Scientists have been studying the injection of CO2 in the subsurface for years. For example, in Sleipner, in the North Sea, millions of tons of carbon dioxide have been injected into a sandstone geological reservoir in the past fifteen years, where CO2 is stored in liquid form. CO2 can also be stored in solid form through mineralization processes, minimising the risk of leakage. Small-scale ongoing projects, such as Carbfix in Iceland, show promising results but questions of efficiency remain.

“The natural process is very effective but too slow, so we wonder whether we could somehow accelerate it so that large quantities of CO2 could be injected underground, without leakage”, explains François Renard, director of the Njord Centre at the University of Oslo and ESRF user.

The natural process

Atmospheric CO2 and water from precipitations naturally react with rocks present at the Earth’s surface – this process is called weathering. Some of these rocks have been produced by volcanic activity (basalts in Iceland) or were exhumed to the Earth’s surface from the mantle (peridotites). When reacting with CO2 and water, they may dissolve partially over geological time scales, liberating magnesium, iron, and calcium ions that can bind with carbon dioxide, in a process called mineral carbonation, which converts CO2 into minerals. The end product is a calcium, iron or magnesium carbonate, which are stable minerals that effectively trap carbon dioxide into a solid form.

Renard and his team are focusing on storing CO2 in basaltic and peridotite rocks, rich in magnesium and calcium, as they are the most efficient environments for it due to their high reactivity. They make up about 70% of the Earth’s surface and are responsible for 1/3 of the trapping of CO2 from the atmosphere through weathering. Estimates suggest that mid-ocean ridges worldwide can store up to 100,000 Gt of CO2. This is more than 2000 times the annual global emissions of CO2.

Once in the basaltic or peridotite rocks, the CO2 quickly reacts with the divalent cations (Ca2+, Mg2+, and Fe2+) from dissolving minerals in the rock and form carbonate minerals. In comparison, it might take several tens of thousands of years for significant amounts of CO2 to mineralize in a sandstone reservoir. After it becomes a mineral, the carbon will not move over geological timescales.

Carbonation at the ESRF

The team is focused on studying how basalts and peridotites can host large quantities of flows of carbon dioxide mixed with water, which will react with the rock to produce carbonate minerals. 

Read more on ESRF website

TexTOM: bringing crystallographic texture analysis to the third dimension

TexTOM: bringing crystallographic texture analysis to the third dimension

Texture tomography (TexTOM) is a cutting-edge 3D crystallographic texture-analysis tool for polycrystalline materials, now available at beamlines ID13 and ID15A, with future expansions planned for additional beamlines. TexTOM offers rapid, quantitative texture analysis with enhanced spatial resolution, making it ideal for complex materials like biominerals, deformed metals, and technical alloys. This technique enables in-situ and operando studies, expanding the possibilities for real-time texture investigations.

Crystallographic texture plays a crucial role in determining the mechanical, electronic, magnetic, and optical properties of polycrystalline materials. Existing techniques, such as 3D X-ray diffraction (3DXRD) [1] and dark-field X-ray microscopy [2], are effective for analyzing well-aligned, narrow structures in technical materials. However, they are limited in their ability to provide comprehensive quantitative texture information in 3D analysis for broader more complex textures, which are typically found in biomaterials, biominerals, or deformed technical materials.

While wide-angle X-ray scattering (WAXS) tensor tomography [3] (derived from small-angle X-ray scattering tensor tomography [4,5,6]) has facilitated more detailed 3D orientation analysis, it lacks a fully quantitative approach due to its reliance on a reciprocal space model of single Bragg reflections. In contrast, typical diffraction patterns contain multiple crystalline reflections, whose intensity and distribution offer valuable additional information. 

TexTOM is a new tool developed by Tilman Grünewald’s group at the Institut Fresnel, Marseille, in collaboration with beamlines ID13 and ID15A, designed to fill the gap in 3D crystallographic texture analysis. The technique utilizes a hyperspherical harmonics [7] approach to model local orientation distribution functions (ODF), enabling the description of crystallographic texture in 3D. By incorporating prior knowledge of crystal symmetry, TexTOM reduces the data required compared to WAXS tensor tomography, thereby accelerating the measurement process and minimizing sample exposure. 

Read more on ESRF website

Image: Fig. 1: Texture tomography (TexTOM). a) Data collection involves raster-scanning a sample through a focused X-ray beam at multiple rotation and tilt angles, capturing a 2D diffraction pattern at each scan point. b) Selected diffractlets form the basis for structural reconstruction. c) Successful reconstruction of a silica biomorph, where a full orientation distribution is determined for each voxel, allowing detailed analysis.