Category: Linac Coherent Light Source (LCLS)

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

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

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

A new world record: LCLS approaches 100,000 pulses per second on the path to a million

A new world record: LCLS approaches 100,000 pulses per second on the path to a million

Experiments running at these higher pulse rates will allow scientists to capture ultrafast processes with greater precision, collect data more efficiently and explore phenomena that were previously out of reach.

Two years after teams at the Department of Energy’s SLAC National Accelerator Laboratory celebrated completion of the Linac Coherent Light Source (LCLS) upgrade project, LCLS-II, the X-ray laser has reached a major milestone: delivering 93 kHz – almost 100,000 pulses per second – a new world record for X-ray free-electron lasers. The achievement marks a critical step toward the machine’s goal of up to 1 million pulses per second, 8,000 times more than the original machine.

Experiments running at these higher pulse rates will allow scientists to capture ultrafast processes with greater precision, collect data more efficiently and explore phenomena that were previously out of reach. 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 energy technologies and medicine.

Read more on the SLAC website

Image: From left, Yuantao Ding, William Colocho and Franz-Josef Decker in SLAC’s accelerator control room during the ramp-up to 93 kHz.

Credit: Olivier Bonin/SLAC National Accelerator Laboratory

Symposium celebrates Claudio Pellegrini, pioneer of SLAC’s X-ray laser

Symposium celebrates Claudio Pellegrini, pioneer of SLAC’s X-ray laser

Leading researchers met at SLAC on Pellegrini’s 90th birthday to honor his ongoing scientific legacy and to explore the future of X-ray free-electron laser science.

Ask anyone about Claudio Pellegrini – distinguished professor emeritus of physics at the University of California, Los Angeles, and adjunct professor of photon science at the Department of Energy’s SLAC National Accelerator Laboratory – and they are quick to share their heartfelt admiration. They describe a gentle giant, widely regarded for his influential work and noble character; a charismatic and curious leader who ushered in a whole new way of doing science; a mentor, friend and someone who has become a father or grandfather figure to many in the accelerator and free-electron laser science community.

On May 9, 2025, on Pellegrini’s 90th birthday, SLAC hosted a special symposium to honor his ongoing scientific legacy. 

Among Pellegrini’s many accomplishments, one moment in time stands out. At a workshop on fourth generation light sources in 1992, he proposed to use SLAC’s historic linear accelerator to build an X-ray free-electron laser. That visionary idea became reality in 2009 when SLAC turned on its Linac Coherent Lightsource (LCLS), the world’s first free-electron laser producing “hard,” or very high-energy, X-rays.

Click through the photo carousel to learn more about the development of the LCLS idea, Pellegrini’s contributions, and what his colleagues had to say about his legacy at the May 9 symposium.

When LCLS came online, it was a revolutionary new facility. With its unprecedented flashes of X-ray light that each only last a few millionths of a billionth of a second and are a billion times brighter than those produced by any previous source, researchers could now do science they could only dream of before. For example, LCLS allowed them to take snapshots of atoms and molecules at work and string them together in molecular movies that reveal chemical reactions and other fundamental ultrafast processes in real time in materials, technology and living things.  

While the goal behind Pellegrini’s proposal was clear from the beginning, it was also apparent that turning it into a working machine would be an extraordinary technological challenge. “It didn’t seem to be impossible, but we certainly needed to do our homework,” Pellegrini remembers. “It took a place like SLAC with its technical capabilities and the collective effort of many talented people in many places to make it happen.” 

Since 2009, similar light sources have been developed around the world. Meanwhile, at SLAC, recent and future upgrades to LCLS ensure that its capabilities keep defining and pushing the frontiers of X-ray science and technology.

The symposium was organized by Uwe Bergmann, Martin L. Perl Endowed Professor of ultrafast X-ray science at the University of Wisconsin, Madison, together with LCLS’s Leilani Conradson, Samira Morton and Brandon Tan.

Read more SLAC website

A new approach allows researchers to catch a photocatalyst in action

A new approach allows researchers to catch a photocatalyst in action

Using SLAC’s X-ray laser, the method revealed atomic motions in a simple catalyst, opening the door to study more complex molecules key to chemical processes in industry and nature.

Catalysts facilitate crucial chemical reactions in nature and industry alike. In a subset of them, catalytic activity is triggered by light. For example, when iron pentacarbonyl – a molecule in which a central iron atom is surrounded by five carbon monoxide groups – is exposed to light, the iron sheds its carbon monoxide groups one after another, creating spots for other molecules to dock on to during a catalytic reaction.  

Although this process has been studied extensively with spectroscopy, a method that shows how energy moves around in molecules, key details of how the catalyst’s atoms change structure after being hit by light remain unknown. 

Now, writing in the journal Nature Communications, a team led by researchers at the Department of Energy’s SLAC National Accelerator Laboratory report how they used ultrafast X-rays from the Linac Coherent Light Source (LCLS), combined with recent theoretical advancements, to reveal those atomic motions on a timescale of femtoseconds, millionths of a billionth of a second. The technique could be used to observe speedy atomic motions in more complex catalysts. 

Understanding how energy flows through molecules and how atoms move in real space and time brings us one step closer to controlling chemical reactions, helping us design materials.Adi NatanSLAC Staff Scientist and Principal Investigator at the Stanford PULSE Institute

“Part of the fun is to make tools that will open new doors,” said Adi Natan, principal investigator and staff scientist at the Stanford PULSE Institute, a joint institute of SLAC and Stanford University. “And being able to see how molecular structures evolve with unprecedented detail will allow us to learn something new about the chemistry of molecules.”

Read more on SLAC website

What will it take to bring fusion energy to the US power grid?

What will it take to bring fusion energy to the US power grid?

In this Q&A, Arianna Gleason discusses the technologies needed to make commercialized fusion energy a reality and how SLAC is advancing this energy frontier. 

By Erin Woodward

Arianna Gleason is an award-winning scientist at the Department of Energy’s SLAC National Accelerator Laboratory who studies matter in its most extreme forms – from roiling magma in the center of our planet to the conditions inside the heart of distant stars. During Fusion Energy Week, we caught up with Gleason about the current state of fusion energy research and how SLAC is helping push the field forward. 

What is fusion energy? 

Fusion is at the heart of every star. The tremendous pressure and temperature at the center of a star fuses atoms together, creating many of the elements you see on the periodic table and generating an immense amount of energy. Fusion is exciting, because it could provide unlimited energy to our power grid. We’re trying to replicate fusion energy here on Earth, though it’s a tremendous challenge of science and engineering. 

Have we ever been able to replicate fusion in a lab? 

Fusion has been at the forefront of scientific inquiry for many decades, but it wasn’t until December 2022 that we reached an incredible watershed moment in fusion research. Using a technique called inertial fusion energy, or IFE, researchers at Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) focused 192 individual lasers on a fuel “target” – about the size of a pea – made of deuterium and tritium. These lasers applied a tremendous force onto the target, and it imploded into a burning plasma. The deuterium and tritium atoms fused together, generating helium and a neutron and producing more energy from the reaction than was used to create it. For less than a trillionth of a second, researchers created the center of a star on Earth. After more than 50 years of fusion research, the world finally achieved net energy gain. 

That’s incredible, but – a trillionth of a second? That seems pretty short. 

Very short! The idea is that this process – this burning plasma – can be repeated many times per second, driven by a series of laser shots that create a source of power. Think of it like a car engine: A spark (the laser) ignites the fuel (the fusion fuel target), which only burns for a short time, but repeated cycles of ignition and burning drive sustained power. In the case of inertial fusion energy, this would be the equivalent of a one million horsepower engine.

Right now, the NIF produces one or two shots each day. We’re trying to go from one shot each day to multiple shots each second. If we can orchestrate these implosions multiple times a second, we can generate a continuous flow of power – and do so in a way that is safe, carbon-free and at a scale that meets the long-term energy demands of our world. 

Now that we know fusion is possible on Earth, how far are we from having this unlimited energy source on our national power grid? 

There are numerous barriers we need to overcome before commercialized fusion energy is a reality. As I said before, we need to move from one laser shot each day to something on the order of 10 shots per second. High repetition rate is critical. Beyond that, we need to develop the technology to deliver the fuel targets into the fusion chamber, track their movements and engage them with lasers at the same rate – 10 times per second. The third challenge is designing the targets themselves to ensure they fuse and generate energy every single time. Right now, our understanding of the physics and materials science of these targets is at an early stage – a very low technology readiness level. 

Even more foundationally, we need people. We need to be training up experts at every level – from power plant operators, technicians and electricians to PhDs in science and engineering. These are good jobs that can be domestically sourced. We need to be educating the workforce, at all levels, for power plant design and operation.

What is SLAC doing to address these challenges? 

SLAC is furthering fusion energy science and technology in several ways, including in partnership with other national labs, universities and private companies. 

One significant opportunity is the challenge of high repetition rates – moving from one laser shot per day to 10 shots every second. SLAC has years of experience on exactly this topic. We are home to the only domestic X-ray free electron laser, the Linac Coherent Light Source (LCLS), and its cutting-edge experimental end stations. We’re leveraging these facilities to build up the capabilities for high-repetition laser-target interactions. 

Read more on SLAC website

New upgrade will supercharge atomic vision of the world’s most powerful X-ray laser

New upgrade will supercharge atomic vision of the world’s most powerful X-ray laser

The high-energy upgrade will keep the U.S. at the forefront of X-ray science and technology, allowing researchers to advance fields such as sustainability, human health and quantum information.

The Department of Energy (DOE) has given the green light for construction to begin on a high-energy upgrade that will further boost the performance of the Linac Coherent Light Source (LCLS), the world’s most powerful X-ray free-electron laser (XFEL) at the DOE’s SLAC National Accelerator Laboratory. When complete, the upgrade will allow scientists to explore atomic-scale processes with unprecedented precision and address fundamental questions in energy storage, catalysis, biology, materials science and quantum physics like never before.

“This high-energy upgrade to LCLS strengthens the lab’s position as a world leader in X-ray and ultrafast science,” said SLAC Lab Director John Sarrao. “With the critical support of the Department of Energy’s Office of Science and our partner labs, the upgrade, when complete, will open new avenues for scientific discovery and innovation. This will continue to attract top talent and foster groundbreaking research across multiple disciplines.”

In 2023, SLAC celebrated completion of the LCLS-II project, taking X-ray science to a whole new level with the addition of a superconducting accelerator, two new magnetic structures, called undulators, to generate soft and hard X-rays from the electron beam, and other major leaps in technology that allow the facility to produce up to a million X-ray pulses per second – 8,000 times more than its predecessor.

The new upgrade project, called LCLS-II-HE, will double the energy of the electron beam coming out of the superconducting electron accelerator, which will more than double the maximum X-ray energy and deliver a 3,000-fold performance increase in average X-ray brightness for “hard,” or high-energy, X-rays. 

“The LCLS-II-HE upgrade will be a transformative advance for the scientific mission of DOE Basic Energy Sciences and the broader scientific community,” said LCLS Director Mike Dunne. “If the LCLS-II upgrade enabled a high-quality movie camera capable of capturing clear and detailed images, the LCLS-II-HE upgrade greatly boosts that camera’s resolution and sensitivity. Scientists will be able to image the atomic-scale motion of materials, chemical systems and biological complexes to address some of the most critical challenges facing our society.”

With favorable Critical Decisions 2 and 3 (CD-2/3) in September 2024, DOE has formally approved construction of the $716M project, representing a significant advancement in X-ray laser technology.

Read more on SLAC website

A novel spray device helps researchers capture fast-moving cell processes

A novel spray device helps researchers capture fast-moving cell processes

Cells are the basic units of life – but many of their fundamental processes happen so fast and at such small length scales that current scientific tools and methods can’t keep up, preventing us from developing a deeper understanding. 

Now, researchers with SLAC National Accelerator Laboratory, Stanford University, Cornell University and other institutions have developed a new approach for watching basic biological processes unfold. The approach, which combines cryogenic electron microscopes with methods developed in X-ray crystallography, could lead to improved medicines and a deeper understanding of cell division, photosynthesis and host-pathogen interactions, among other subjects.

“Many cellular processes happen on a millisecond timescale,” SLAC scientist and paper co-author Pete Dahlberg said. “With our new technique, we can poke a cell and then pick a moment in time that we want to snap a clear image of its response.”

Reimagining a powerful spray tool

For many decades, scientists have relied on imaging techniques known as cryogenic electron microscopy (cryo-EM) and cryogenic electron tomography (cryo-ET) to see inside of cells, proteins, and other organisms and molecules. Both techniques use electron microscopes to capture snapshots of flash-frozen samples, which have revealed cellular structures in extraordinary detail. These approaches involve putting a sample on a thin small disk known as an electron microscopy grid and plunging it into a cryogenic liquid to freeze it very rapidly. This is great at preserving cellular samples in their native state, but the frozen snapshots don’t tell researchers much about dynamics. It is sort of like trying to learn dance moves by taking random images of someone dancing. 

Currently in similar cryo-ET experiments, researchers hand-mix cell samples in order to take images of them in response to a stimuli. But hand-mixing takes time, kind of like mixing pancake batter by hand instead of with an electric mixer, meaning that experimenters can only observe changes in an organism at about ten second intervals – hundreds of times longer than many important processes take. 

“When you hand-mix and freeze cells in cryo-ET experiments, you are often too slow to capture the changes you really care about. That can limit your ability to understand important biological processes,” SLAC researcher and paper co-author Cali Antolini said.

Researchers therefore turned to a spray nozzle device that is often used at X-ray free-electron laser (XFEL) and synchrotron facilities to mix samples for crystallography experiments. The device, known as a mixing injector coupled Gas Dynamic Virtual Nozzle (GDVN), is often used to study molecular movements that occur on extremely short timescales, like femtoseconds after activation with light or on millisecond to second timescales using chemical mixing, at XFELs like SLAC’s Linac Coherent Light Source (LCLS).

Read more on SLAC website

Image: A graphic representation of the spray nozzle device. The sample cells (green) mix with the simulant solution as the cells travel from left to right, out of the spray nozzle.

Credit: Greg Stewart/SLAC National Accelerator Laboratory

Electron bubbles modelled from X-ray laser data

Electron bubbles modelled from X-ray laser data

An international team of scientists uncovers a groundbreaking model for the effects of radiation in water systems

What happens when radiation hits water? This is a question that has an impact every time you get an X-ray at the doctor’s office, given you are mostly made of water. A team of theoretical physicists at DESY has worked on data taken by colleagues from Argonne National Laboratory in the US at the LCLS X-ray laser in California to get a better answer to this question. What they found may settle a controversy in physics about the presence of free electrons in water and how they behave at very short time scales: the electrons, unbound to atoms, become sequestered in bubbles in cage-like structures between individual water molecules. These findings are reported in the Journal of the American Chemical Society.

Free electrons are electrons that are not bound to atoms. In water that comes into contact with radiation, free electrons emerge from the water molecules as they ionise due to the radiation. How the electrons flow between the water molecules in this situation has been a topic of discussion for a longer time.

In their work at LCLS at the SLAC National Accelerator Laboratory, the experimental team, led by Argonne scientist Linda Young, saw odd signatures associated with the water molecules excited by lasers and imaged by the X-ray laser. They found structures among the molecules using X-ray absorption spectroscopy. In order to gain a better understanding of what these results meant, the experiment team turned to theoretical physicists in Hamburg.

A team led by DESY scientist Ludger Inhester of the Center for Free-Electron Laser Science examined the data and began making models from the data in coordination with the experimental team. Together their findings show that the free electrons in the water form bubble structures that are then caged in by water molecules, similar to how chemicals are solvated in water at the molecular level. In particular, the DESY team managed to show the process behind this solvation of electrons in the water and its parameters.

Read more on DESY website

Image: Using the X-ray laser LCLS in California, the experiment team, led by Argonne scientist Linda Young, could image the structures of the water molecules surrounding the electron bubbles. The theory team in Hamburg, led by CFEL senior scientist Ludger Inhester was able to model how the bubble itself behaved using the experiment team’s data.

Credit: DESY/ Arturo Sopena Moros

‘Diamond rain’ on icy planets offers clues into magnetic field mysteries

‘Diamond rain’ on icy planets offers clues into magnetic field mysteries

A new experiment suggests that this exotic precipitation forms at even lower pressures and temperatures than previously thought and could influence the unusual magnetic fields of Neptune and Uranus.

An international team of researchers led by researchers from the Department of Energy’s SLAC National Accelerator Laboratory gained new insights into the formation of diamonds on icy planets such as Neptune and Uranus. Scientists believe that, following their formation, these diamonds would slowly sink deeper into the planetary interior in response to gravitational forces, resulting in a ‘rain’ of precious stones from higher layers. 

The results, published today in Nature Astronomy, suggest that this “diamond rain” forms at even lower pressures and temperatures than previously thought and provide clues into the origin of the complex magnetic fields of Neptune and Uranus. 

“‘Diamond rain’ on icy planets presents us with an intriguing puzzle to solve,” said SLAC scientist Mungo Frost, who led the research. “It provides an internal source of heating and transports carbon deeper into the planet, which could have a significant impact on their properties and composition. It might kick off movements within the conductive ices found on these planets, influencing the generation of their magnetic fields.”

Longer timescales

In earlier work conducted at SLAC’s Linac Coherent Light Source (LCLS) X-ray free-electron laser (XFEL), scientists were able to observe “diamond rain” as it formed in high-pressure conditions, confirming the possibility of diamond formation on icy planets, which are primarily composed of water, ammonia, and hydrocarbons. They later discovered that the presence of oxygen makes diamond formation more likely, allowing diamonds to form and grow at a wider range of conditions and throughout more planets.

Previously, the high pressures and temperatures were generated by shock compressing the hydrocarbons with high power lasers, which only allows the conditions to be maintained for a few nanoseconds.  In this new experiment, conducted at the European X-ray free-electron laser in Germany, the team studied the reaction over much longer timescales than other experiments using a different approach.  

Read more on the SLAC website

New AI-driven tool streamlines experiments

New AI-driven tool streamlines experiments

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have demonstrated a new approach to peer deeper into the complex behavior of materials. The team harnessed the power of machine learning to interpret coherent excitations, collective swinging of atomic spins within a system. 

This groundbreaking research, published recently in Nature Communications, could make experiments more efficient, providing real-time guidance to researchers during data collection, and is part of a DOE-funded project led by Howard University including researchers at SLAC and Northeastern University to use machine learning to accelerate research in materials. 

The team created this new data-driven tool using “neural implicit representations,” a machine learning development used in computer vision and across different scientific fields such as medical imaging, particle physics and cryo-electron microscopy. This tool can swiftly and accurately derive unknown parameters from experimental data, automating a procedure that, until now, required significant human intervention.

Peculiar behaviors

Collective excitations help scientists understand the rules of systems, such as magnetic materials, with many parts. When seen at the smallest scales, certain materials show peculiar behaviors, like tiny changes in the patterns of atomic spins. These properties are key for many new technologies, such as advanced spintronics devices that could change how we transfer and store data. 

To study collective excitations, scientists use techniques such as inelastic neutron or X-ray scattering. However, these methods are not only intricate, but also resource-intensive given, for example, the limited availability of neutron sources. 

Machine learning offers a way to address these challenges, although even then there are limitations. Past experiments used machine learning techniques to enhance the accuracy of X-ray and neutron scattering data interpretation. These efforts relied on traditional image-based data representations. But the team’s new approach, using neural implicit representations, takes a different route. 

Read more on SLAC website

LCLS-II ushers in a new era of science

LCLS-II ushers in a new era of science

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

SLAC researchers take important step toward developing cavity-based X-ray laser technology

SLAC researchers take important step toward developing cavity-based X-ray laser technology

Researchers have announced an important step in the development of a next-gen technology for making X-ray free-electron laser pulses brighter and more stable: They used precisely aligned mirrors made of high-quality synthetic diamond to steer X-ray laser pulses around a rectangular racetrack inside a vacuum chamber.

Setups like these are at the heart of cavity-based X-ray free-electron lasers, or CBXFELs, which scientists are designing to make X-ray laser pulses brighter and cleaner – more like regular laser beams are today.

“The successful delivery of a cavity-based X-ray free-electron laser will mark the start of a new generation of X-ray science by providing a huge leap in beam performance,” said Mike Dunne, director of the Linac Coherent Light Source (LCLS) X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory, where the work was carried out.

“There are still many challenges to overcome before we get there,” he said. “But demonstration of this first integrated step is very encouraging, showing that we have the approach and tools needed to sustain high cavity performance.”

The SLAC research team described their work in a paper published in Nature Photonics. Early results were so encouraging, they said, that the lab is already working with DOE’s Argonne National Laboratory, its longtime collaborator on the subject, to design and install the next, bigger version of the experimental cavity system in the LCLS undulator tunnel.

Despite their name, X-ray laser pulses are not yet fully laser-like. They’re created by making accelerated electrons wiggle through sets of magnets called undulators. This forces them to give off X-rays, which are shaped into powerful pulses for probing matter at the atomic scale. At LCLS, pulses arrive 120 times a second, a rate that will soon increase to a million times per second. 

But because of the way X-ray laser pulses are generated, they vary in intensity and contain an unpredictable mix of wavelengths. This creates what scientists call “noise,” which muddles their view of samples they are probing. 

The introduction of a cavity has been proposed to overcome this problem, adopting the approach used by conventional optical lasers. Cavities increase the coherence of lasers ­by preferentially selecting light of a single wavelength whose peaks and troughs line up with each other. ­But the mirrors that bounce light around in regular laser cavities won’t work for X-ray laser pulses – all you would get would be a smoking hole in your mirror where the X-rays drilled through. 

The idea of using crystals – and, more recently, synthetic diamond crystals – as mirrors to smooth and help amplify X-ray pulses inside a cavity has been around for a long time, said Diling Zhu, who led the experimental team with fellow SLAC scientist Gabriel Marcus.

Read more on SLAC website

Image: A top-down view of one of the cavity vacuum chambers. Two diamond mirrors can be seen in the upper and lower left corners, each one mounted on four motors that control its angle and position. At upper right, the precision diamond grating that brings X-ray pulses into the chamber is mounted on a screen holder. 

Credit: Diling Zhu/SLAC National Accelerator Laboratory

Elusive missing step in the final act of photosynthesis

Elusive missing step in the final act of photosynthesis

After decades of effort and help from SLAC’s X-ray laser, scientists have finally seen the process by which nature creates the oxygen we breathe.

Photosynthesis plays a crucial role in shaping and sustaining life on Earth, yet many aspects of the process remain a mystery. One such mystery is how Photosystem II, a protein complex in plants, algae and cyanobacteria, harvests energy from sunlight and uses it to split water, producing the oxygen we breathe. Now researchers from the Department of Energy’s SLAC National Accelerator Laboratory and Lawrence Berkeley National Laboratory, together with collaborators from Uppsala University, Humboldt University, and other institutions have succeeded in cracking a key secret of Photosystem II.

Using SLAC’s Linac Coherent Light Source (LCLS) and the SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, they captured for the first time in atomic detail what happens in the final moments leading up to the release of breathable oxygen. The data reveal an intermediate reaction step that had not been observed before.

Find out more on the SLAC website

New SLAC-Stanford Battery Center targets roadblocks to a sustainable energy transition

New SLAC-Stanford Battery Center targets roadblocks to a sustainable energy transition

The center at SLAC aims to bridge the gaps between discovering, manufacturing and deploying innovative energy storage solutions. 

The Department of Energy’s SLAC National Accelerator Laboratory and Stanford University today announced the launch of a new joint battery center at SLAC. It will bring together the resources and expertise of the national lab, the university and Silicon Valley to accelerate the deployment of batteries and other energy storage solutions as part of the energy transition that’s essential for addressing climate change.

A key part of this transition will be to decarbonize the world’s transportation systems and electric grids ­– to power them without fossil fuels. To do so, society will need to develop the capacity to store several hundred terawatt-hours of sustainably generated energy. Only about 1% of that capacity is in place today.

Filling the enormous gap between what we have and what we need is one of the biggest challenges in energy research and development. It will require that experts in chemistry, materials science, engineering and a host of other fields join forces to make batteries safer, more efficient and less costly and manufacture them more sustainably from earth-abundant materials, all on a global scale. 

The SLAC-Stanford Battery Center will address that challenge. It will serve as the nexus for battery research at the lab and the university, bringing together large numbers of faculty, staff scientists, students and postdoctoral researchers from SLAC and Stanford for research, education and workforce training. 

 “We’re excited to launch this center and to work with our partners on tackling one of today’s most pressing global issues,” said interim SLAC Director Stephen Streiffer. “The center will leverage the combined strengths of Stanford and SLAC, including experts and industry partners from a wide variety of disciplines, and provide access to the lab’s world-class scientific facilities. All of these are important to move novel energy storage technologies out of the lab and into widespread use.”

Expert research with unique tools

Research and development at the center will span a vast range of systems – from understanding chemical reactions that store energy in electrodes to designing battery materials at the nanoscale, making and testing devices, improving manufacturing processes and finding ways to scale up those processes so they can become part of everyday life. 

“It’s not enough to make a game-changing battery material in small amounts,” said Jagjit Nanda, a SLAC distinguished scientist, Stanford adjunct professor and executive director of the new center, whose background includes decades of battery research at DOE’s Oak Ridge National Laboratory. “We have to understand the manufacturing science needed to make it in larger quantities on a massive scale without compromising on performance.”

Longstanding collaborations between SLAC and Stanford researchers have already produced many important insights into how batteries work and how to make them smaller, lighter, safer and more powerful. These studies have used machine learning to quickly identify the most promising battery materials from hundreds made in the lab, and measured the properties of those materials and the nanoscale details of battery operation at the lab’s synchrotron X-ray facility. SLAC’s X-ray free-electron laser is available, as well, for fundamental studies of energy-related materials and processes. 

SLAC and Stanford also pioneered the use of cryogenic electron microscopy (cryo-EM), a technique developed to image biology in atomic detail, to get the first clear look at finger-like growths that can degrade lithium-ion batteries and set them on fire. This technique has also been used to probe squishy layers that build up on electrodes and must be carefully managed, in research performed at the Stanford Institute for Materials and Energy Sciences (SIMES).

Nanda said the center will also focus on making energy storage more sustainable, for instance by choosing materials that are abundant, easy to recycle and can be extracted in a way that’s less costly and produces fewer emissions.

Read more on the SLAC website

Artificial intelligence deciphers detector “clouds” to accelerate materials research

Artificial intelligence deciphers detector “clouds” to accelerate materials research

A machine learning algorithm automatically extracts information to speed up – and extend – the study of materials with X-ray pulse pairs.

X-rays can be used like a superfast, atomic-resolution camera, and if researchers shoot a pair of X-ray pulses just moments apart, they get atomic-resolution snapshots of a system at two points in time. Comparing these snapshots shows how a material fluctuates within a tiny fraction of a second, which could help scientists design future generations of super-fast computers, communications, and other technologies.

Resolving the information in these X-ray snapshots, however, is difficult and time intensive, so Joshua Turner, a lead scientist at the Department of Energy’s SLAC National Accelerator Center and Stanford University, and ten other researchers turned to artificial intelligence to automate the process. Their machine learning-aided method, published October 17 in Structural Dynamics, accelerates this X-ray probing technique, and extends it to previously inaccessible materials.

“The most exciting thing to me is that we can now access a different range of measurements, which we couldn’t before,” Turner said.

Handling the blob

When studying materials using this two-pulse technique, the X-rays scatter off a material and are usually detected one photon at a time. A detector measures these scattered photons, which are used to produce a speckle pattern – a blotchy image that represents the precise configuration of the sample at one instant in time. Researchers compare the speckle patterns from each pair of pulses to calculate fluctuations in the sample.

“However, every photon creates an explosion of electrical charge on the detector,” Turner said. “If there are too many photons, these charge clouds merge together to create an unrecognizable blob.” This cloud of noise means the researchers must collect tons of scattering data to yield a clear understanding of the speckle pattern.

“You need a lot of data to work out what’s happening in the system,” said Sathya Chitturi, a Ph.D. student at Stanford University who led this work. He is advised by Turner and coauthor Mike Dunne, director of the Linac Coherent Light Source (LCLS) X-ray laser at SLAC. 

Read more on the SLAC website

Image: A speckle pattern typical of the sort seen at LCLS’s detectors

Credit: Courtesy Joshua Turner

Researchers resolve decades-long debate about shock-compressed silicon with unprecedented detail

Researchers resolve decades-long debate about shock-compressed silicon with unprecedented detail

They saw how the material finds a path to contorting and flexing to avoid being irreversibly crushed.

BY ALI SUNDERMIER

Silicon, an element abundant in Earth’s crust, is currently the most widely used semiconductor material and is important in fields like engineering, geophysics and plasma physics. But despite decades of studies, how the material transforms when hit with powerful shockwaves has been a topic of longstanding debate.

“One might assume that because we have already studied silicon in so many ways there is nothing left to discover,” said Silvia Pandolfi, a researcher at the Department of Energy’s SLAC National Accelerator Laboratory. “But there are still some important aspects of its behavior that are not clear.”

Now, researchers at SLAC have finally put this controversy to rest, providing the first direct, high-fidelity view of how a single silicon crystal deforms during shock compression on nanosecond timescales. To do so, they studied the crystal with X-rays from SLAC’s Linac Coherent Light Source (LCLS) X-ray laser. The team published their results in Nature Communications on September 21st. What they learned could lead to more accurate models that better predict what will happen to certain materials in extreme conditions.

“This is a great example of an experiment that’s necessary to better understand certain materials,” said SLAC scientist Arianna Gleason, who was the principal investigator. “You have to start simple, with single crystals, to know what you’re tracking and understand it in really detailed ways before you can build up complexity to give way to, say, the next semiconductor of the 21st Century that will allow the electronics industry to continue the remarkable progress seen in the past 50 years.”

Read more on the SLAC website