X-ray laser – Lightsources.org

More than just viscous: researchers examine movement of proteins

2026/08/072026/08/12

Study yields new insights into how proteins navigate crowded cell-like environments

How do proteins find their way through the dense crowd inside a cell? An international research team, including researchers from the University of Siegen, has investigated this question at the world’s largest X-ray laser – the European XFEL. The results of the measurements show that it is not just the viscosity of the environment that is decisive. The way the molecules influence one another also plays an important role – and can even lead to individual proteins initially moving faster than expected under certain conditions. The study has now been published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS).

“Conducting research at European XFEL was a fantastic opportunity and a wonderful experience. As proteins are very small – we’re talking in the nanometre range here – short-wavelength X-rays are well suited to studying them,” says Michelle Dargasz, lead author of the study and a PhD student working with Christian Gutt, Professor of Solid-State Physics at the University of Siegen.

Read more on the European XFEL website

Image: Co-authors Michelle Dargasz (right) and Nimmi Das Anthuparambil at the ‘Materials Imaging and Dynamics’ (MID) instrument at the European XFEL, where the experiments were carried out.

Credit: University of Siegen

Light-controlled beta blockers show promise for new and improved medicines

2026/04/062026/04/23

Researchers used X-ray lasers, including SLAC’s LCLS, to control a modified cardiovascular drug with light and captured snapshots showing how it binds to proteins.

Key takeaways:

Beta blockers bind to protein receptors that are key to fight-or-flight responses, leading to effects such as lowered heart rate and blood pressure.
Using X-ray free-electron lasers at SLAC and in Switzerland, an international team of researchers investigated a beta blocker modified with a light-sensitive bond.
They controlled the drug’s interaction using light and reconstructed X-ray images of the reaction, demonstrating how light could be used to improve medications.

Researchers are illuminating a new route for drug delivery – literally, by controlling drugs with light. Recently, an international team led by the Swiss Paul Scherrer Institute and including researchers from the Department of Energy’s SLAC National Accelerator Laboratory used light to control a modified beta blocker and took X-ray laser snapshots of its interaction with a protein receptor.

Not only did the team demonstrate they could control the beta blocker medicine with light, but they also captured 3D images of the interaction at multiple time points. The images revealed that light can switch the beta blocker between different positions on the receptor, which suggests it may be possible to fine tune the drug’s potency while it’s in the body. The findings, published in the journal Angewandte Chemie, also demonstrate how X-ray lasers like the Linac Coherent Light Source (LCLS) can be harnessed to study medicines at the atomic level. This can aid the design of drugs that precisely target protein receptors and therefore have fewer side effects.

Read more on the SLAC website

Revealing quantum fluctuations in complex molecules

2025/08/072025/08/08

Due to the Heisenberg uncertainty principle of quantum physics, atoms and molecules never come completely to rest, even in their lowest energy state. Researchers at European XFEL in Schenefeld near Hamburg have now been able to directly measure this quantum motion in a complex molecule for the first time. For this, however, as they report in the journal Science, they had to make the molecule explode in the process.

Absolute standstill only exists in classical physics. In the quantum world, even the ground state with the lowest energy is characterised by persistent fluctuations. This is due to a quantum-mechanical principle discovered by Werner Heisenberg a hundred years ago during the development of quantum mechanics. The so-called zero-point fluctuations are a quantum effect that prevents atoms from remaining precisely at a fixed position, even at temperatures near absolute zero. At European XFEL in Schenefeld, researchers have now made the previously invisible directly observable – and the quantum world a bit more tangible.

An international team led by Rebecca Boll from the SQS (Small Quantum Systems) instrument at European XFEL in Schenefeld, Ludger Inhester from the DESY research centre, and Till Jahnke from the Max Planck Institute for Nuclear Physics in Heidelberg, succeeded in visualising the collective trembling of an entire molecule. Using a sophisticated experiment and refined data analysis, they were able to measure the quantum fluctuations of the 2-iodopyridine molecule (C₅H₄IN), which consists of eleven atoms – a milestone in molecular imaging. They describe their work in the renowned journal Science.

The researchers employed a method as spectacular as its name: Coulomb Explosion Imaging. The ultrashort, extremely intense X-ray laser pulses of European XFEL strip numerous electrons from the atoms of individual 2-iodopyridine molecules very rapidly. The remaining atomic cores become positively charged, repelling each other. The result resembles a microscopic big bang: the atomic cores fly apart in an explosion.

Read more on European XFEL website

Image: Visualisation of collective quantum fluctuations of a complex 2-iodopyridine molecule

Credit: European XFEL / Tobias Wüstefeld)

Milestone for novel atomic clock

2023/09/272023/09/28

X-ray laser shows possible route to substantially increased precision time measurement

An international research team has taken a decisive step toward a new generation of atomic clocks. At the European XFEL X-ray laser, the researchers have created a much more precise pulse generator based on the element scandium, which enables an accuracy of one second in 300 billion years – that is about a thousand times more precise than the current standard atomic clock based on caesium. The team presents its success in the journal Nature.

Atomic clocks are currently the world’s most accurate timekeepers. These clocks have used electrons in the atomic shell of chemical elements, such as caesium, as a pulse generator in order to define the time. These electrons can be raised to a higher energy level with microwaves of a known frequency. In the process, they absorb the microwave radiation. An atomic clock shines microwaves at caesium atoms and regulates the frequency of the radiation such that the absorption of the microwaves is maximised; experts call this a resonance. The quartz oscillator that generates the microwaves can be kept so stable with the help of resonance that caesium clocks will be accurate to within one second within 300 million years.

Crucial to the accuracy of an atomic clock is the width of the resonance used. Current caesium atomic clocks already use a very narrow resonance; strontium atomic clocks achieve a higher accuracy with only one second in 15 billion years. Further improvement is practically impossible to achieve with this method of electron excitation. Therefore, teams around the world have been working for several years on the concept of a “nuclear” clock, which uses transitions in the atomic nucleus as the pulse generator rather than in the atomic shell. Nuclear resonances are much more acute than the resonances of electrons in the atomic shell, but also much harder to excite.

At the European XFEL the team could now excite a promising transition in the nucleus of the element scandium, which is readily available as a high-purity metal foil or as the compound scandium dioxide This resonance requires X-rays with an energy of 12.4 kiloelectronvolts (keV, which is about 10,000 times the energy of visible light) and has a width of only 1.4 femtoelectronvolts (feV). This is 1.4 quadrillionths of an electronvolt, which is only about one tenth of a trillionth of the excitation energy (10^-19). This makes an accuracy of 1:10,000,000,000,000 possible. “This corresponds to one second in 300 billion years,” says DESY researcher Ralf Röhlsberger, who works at the Helmholtz Institute Jena, a joint facility of the GSI Helmholtz Centre for Heavy Ion Research, the Helmholtz Zentrum Dresden-Rossendorf (HZDR), and DESY.

Read more on the DESY website

Image: An artist’s rendition of the scandium nuclear clock: scientists used the X-ray pulses of the European XFEL to excite in the atomic nucleus of scandium the sort of processes that can generate a clock signal – at an unprecedented precision of one second in 300 billion years.

Credit: European XFEL/Helmholtz Institute Jena, Tobias Wüstefeld/Ralf Röhlsberger

LCLS-II ushers in a new era of science

2023/09/182023/09/19

SLAC fires up the world’s most powerful X-ray laser

With up to a million X-ray flashes per second, 8,000 times more than its predecessor, it transforms the ability of scientists to explore atomic-scale, ultrafast phenomena that are key to a broad range of applications, from quantum materials to clean energy technologies and medicine.

The newly upgraded Linac Coherent Light Source (LCLS) X-ray free-electron laser (XFEL) at the Department of Energy’s SLAC National Accelerator Laboratory successfully produced its first X-rays, and researchers around the world are already lined up to kick off an ambitious science program.

The upgrade, called LCLS-II, creates unparalleled capabilities that will usher in a new era in research with X-rays. Scientists will be able to examine the details of quantum materials with unprecedented resolution to drive new forms of computing and communications; reveal unpredictable and fleeting chemical events to teach us how to create more sustainable industries and clean energy technologies; study how biological molecules carry out life’s functions to develop new types of pharmaceuticals; and study the world on the fastest timescales to open up entirely new fields of scientific investigation.

“This achievement marks the culmination of over a decade of work,” said LCLS-II Project Director Greg Hays. “It shows that all the different elements of LCLS-II are working in harmony to produce X-ray laser light in an entirely new mode of operation.”

Reaching “first light” is the result of a series of key milestones that started in 2010 with the vision of upgrading the original LCLS and blossomed into a multi-year ($1.1 billion) upgrade project involving thousands of scientists, engineers, and technicians across DOE, as well as numerous institutional partners.

“For more than 60 years, SLAC has built and operated powerful tools that help scientists answer fundamental questions about the world around us. This milestone ensures our leadership in the field of X-ray science and propels us forward to future innovations,” said Stephen Streiffer, SLAC’s interim laboratory director. “It’s all thanks to the amazing efforts of all parts of our laboratory in collaboration with the wider project team.”

Read more on the SLAC website

Image: The newly upgraded Linac Coherent Light Source (LCLS) X-ray free-electron laser (XFEL) at the Department of Energy’s SLAC National Accelerator Laboratory successfully produced its first X-rays. The upgrade, called LCLS-II, creates unparalleled capabilities that will usher in a new era in research with X-rays.

Credit: Greg Stewart/SLAC National Accelerator Laboratory

Secrets of skyrmions revealed

2021/10/142021/10/14

Why skyrmions could have a lot in common with glass and high-temperature superconductors

Spawned by the spins of electrons in magnetic materials, these tiny whirlpools behave like independent particles and could be the future of computing. Experiments with SLAC’s X-ray laser are revealing their secrets.

Scientists have known for a long time that magnetism is created by the spins of electrons lining up in certain ways. But about a decade ago, they discovered another astonishing layer of complexity in magnetic materials: Under the right conditions, these spins can form little vortexes or whirlpools that act like particles and move around independently of the atoms that spawned them.

The tiny whirlpools are called skyrmions, named after Tony Skyrme, the British physicist who predicted their existence in 1962. Their small size and sturdy nature – like knots that are hard to undo – have given rise to a rapidly expanding field devoted to understanding them better and exploiting their strange qualities.

“These objects represent some of the most sophisticated forms of magnetic order that we know about,” said Josh Turner, a staff scientist at the Department of Energy’s SLAC National Accelerator Laboratory and principal investigator with the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC.