From SLAC National Accelerator Lab: “Peering into 36-million-degree plasma with SLAC’s X-ray laser”

From SLAC National Accelerator Lab

October 2, 2018
Ali Sundermier
For commnication
communications@slac.stanford.edu

At the Matter in Extreme Conditions (MEC) instrument at LCLS, the researchers zapped knuckle-shaped samples with a laser to create plasma, then used an X-ray scattering technique to watch it expand and collide. (Matt Beardsley/SLAC National Accelerator Laboratory)

When you hit a piece of metal with a strong enough laser pulse you get a plasma – a hot, ionized gas found in everything from lightning to the sun. Studying it helps scientists understand what’s going on inside stars and could enable new types of particle accelerators for cancer treatment.

Now a team of researchers has used an X-ray laser to measure, for the first time, how a plasma created by a laser blast expands in the hundreds of femtoseconds (quadrillionths of a second) after it’s created. Their technique could eventually reveal tiny instabilities in the plasma that swirl like cream in a cup of coffee.

The experiments at the Department of Energy’s SLAC National Accelerator Laboratory involved scientists from SLAC, German research center Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and other institutions, and was reported in Physical Review X in September.

Blasting cancer cells

Led by scientist Thomas Kluge at HZDR, the researchers have been working to harness the behavior of plasma to create a new type of particle accelerator for proton therapy, an existing cancer treatment that involves blasting tumors with charged particles rather than X-rays. This approach is gentler on the surrounding healthy tissue than traditional radiation therapy.

When solid matter is zapped with a laser the interaction forms a plasma, causing a steady stream of protons to burst out of the back side of the sample. The researchers hope to use the proton streams to storm tumors and obliterate cancer cells. But producing these fast protons in a reliable way requires a better understanding of how plasma changes as it expands.

“Instabilities can arise from the complex streams of electrons and ions moving back and forth in the plasma,” Kluge says. “You probably know one of these instabilities from the mushroom-shaped clouds that form when you drip milk into your morning coffee.”

Hotter than ever

Until now, it was difficult to probe plasma changes directly because they’re so tiny and happen on extremely fast time scales. This work, says Josefine Metzkes-Ng, co-author and junior group leader at HZDR, could only be done at SLAC where the researchers used a high-power, short-pulse optical laser beam to create the plasma and the Linac Coherent Light Source X-ray free-electron laser to probe it.

SLAC/LCLS

At the Matter in Extreme Conditions (MEC) instrument at LCLS, researchers create incredibly hot and dense matter that mimics the extreme conditions in the hearts of stars and planets. Simulations show that the researchers achieved a new temperature record for matter studied with a free-electron laser: 36 million degrees Fahrenheit, almost 10 million degrees hotter than the sun’s core.

The researchers fabricated solid samples that consisted of raised silicon bars, like knuckles sticking out from a fist. They found that in the quadrillionths of seconds after they zapped the sample with intense, short pulses from the optical laser, tiny amounts of plasma stacked up between the knuckles. A special form of scattering that uses X-ray pulses from LCLS allowed them to peer inside the plasma to follow its evolution.

This technique will pave the way for better understanding plasma instabilities, allowing researchers to create proton sources for cancer therapy with relatively small footprints that, unlike conventional accelerators, can be operated within a hospital. It will also be useful in research relevant to fusion energy, other types of novel particle accelerators and laboratory astrophysics.

Speedy cosmic particles

Siegfried Glenzer, director of the High Energy Density Division at SLAC, who helped with the paper, is especially excited about the prospect of using this technique to better understand the astrophysical processes that give cosmic rays – subatomic space particles that plunge into Earth’s atmosphere at almost the speed of light – their extreme energies.

The highest-energy cosmic rays can pack a force comparable to that of a major league fastball hurtling toward a batter at 100 mph, condensed into a single subatomic particle. To accelerate a proton to the same energies as these cosmic rays, scientists would have to build an accelerator that sends particles traveling from Earth to Saturn and back.

Using LCLS, scientists are able to recreate some of the astrophysical processes that may produce these high-energy cosmic rays, such as energetic jets that shoot out from the turbulent hearts of active galaxies. Now the new technique will allow them to directly observe the plasma instabilities that might be responsible for accelerating cosmic rays.

“Cosmic rays are the largest particle accelerators known to mankind,” Glenzer says. “They have a million times higher energy than particles accelerated in the Large Hadron Collider. Recently, astronomers traced a cosmic ray particle to an active galactic nucleus jet. Our goal is to produce these types of jets in the laboratory so we can study the formation of these instabilities and show whether they can accelerate particles to such high energies and, if so, how it happens.”

Flipping the light switch

According to Kluge, “This research has opened the black box of how short-pulse lasers interact with solids, allowing us to directly see a little of what’s going on, which previously could only be simulated with largely unverified atomic models.

“It’s a little like switching on a light,” he says. “Although we have some ideas, we don’t know what we will find, but surely it will help us develop the next generation of laser-based ion accelerators and could shape new applications in astrophysics, medicine and plasma physics. For me as a theorist and simulation guy, the most exciting thing about this project is that I can now lay my simulations aside and look at the real thing.”

The research team also included scientists from Technical University Dresden, European XFEL, University of Siegen, Friedrich Schiller University Jena and Leibniz Institute of Photonic Technology, all in Germany.

LCLS is a DOE Office of Science user facility. Funding was provided by the DOE Office of Science.

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SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

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From Lawrence Berkeley National Lab: “Toward a New Light: Advanced Light Source Upgrade Project Moves Forward”

From Lawrence Berkeley National Lab

September 25, 2018
Glenn Roberts Jr.
geroberts@lbl.gov
(510) 486-5582

VIDEO: Berkeley Lab’s Advanced Light Source takes a next step toward a major upgrade. (Credit: Berkeley Lab)

The Advanced Light Source (ALS), a scientific user facility at the Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab), has received federal approval to proceed with preliminary design, planning and R&D work for a major upgrade project that will boost the brightness of its X-ray beams at least a hundredfold.

LBNL/ALS

The upgrade will give the ALS, which this year celebrates its 25th anniversary, brighter beams with a more ordered structure – like evenly spaced ripples in a pond – that will better reveal nanoscale details in complex chemical reactions and in new materials, expanding the envelope for scientific exploration.

“This upgrade will make it possible for Berkeley Lab to be the leader in soft X-ray research for another 25 years, and for the ALS to remain at the center of this Laboratory for that time,” said Berkeley Lab Director Mike Witherell.

Steve Kevan, ALS Director, added, “The upgrade will transform the ALS. It will expand our scientific frontiers, enabling studies of materials and phenomena that are at the edge of our understanding today. And it will renew the ALS’s innovative spirit, attracting the best researchers from around the world to our facility to conduct their experiments in collaboration with our scientists.”

This computer rendering provides a top view of the ALS and shows equipment that will be installed during the ALS-U project. (Credit: Berkeley Lab)

The latest approval by the DOE, known as Critical Decision 1 or CD-1, authorizes the start of engineering and design work to increase the brightness and to more precisely focus the beams of light produced at the ALS that drive a broad range of science experiments. The upgrade project is dubbed ALS-U.

The dozens of beamlines maintained and operated by Berkeley Lab staff and scientists at the ALS conduct experiments simultaneously at all hours, attracting more than 2,000 researchers each year from across the country and around the globe through its role in a network of DOE Office of Science User Facilities.

This upgrade is intended to make the ALS the brightest storage ring-based source of soft X-rays in the world. Soft X-rays have an energy range that is especially useful for observing chemistry in action and for studying a material’s electronic and magnetic properties in microscopic detail.

Click the play button on the full article at bottom left to view a slideshow. This slideshow chronicles the history of the Advanced Light Source and the building that houses it, which was formerly home to a 184-inch cyclotron – another type of particle accelerator. It also shows the science conducted at the ALS and includes computer renderings of new equipment that will be installed as a part of the ALS-U project. (Credit: Berkeley Lab)

The planned upgrade will significantly increase the brightness of the ALS by focusing more light on a smaller spot. X-ray beams that today are about 100 microns (thousandths of an inch) across – smaller than the diameter of a human hair – will be squeezed down to just a few microns after the upgrade.

“That’s very exciting for us,” said Elke Arenholz, a senior staff scientist at the ALS. The upgrade will imbue the X-rays with a property known as “coherence” that will allow scientists to explore more complex and disordered samples with high precision. The high coherence of the soft X-ray light generated by the ALS-U will approach a theoretical limit.

“We can take materials that are more in their natural state, resolve any fluctuations, and look much more closely at the structure of materials, down to the nanoscale,” Arenholz said.

Among the many applications of these more precise beams are smaller-scale explorations of magnetic properties in multilayer data-storage materials, she said, and new observations of battery chemistry and other reactions as they occur. The upgrade should also enable faster data collection, which can allow researchers to speed up their experiments, she noted.

“We will have a lot of very interesting, new data that we couldn’t acquire before,” she said. Analyzing that data and feeding it back into new experiments will also draw upon other Berkeley Lab capabilities, including sample fabrication, complementary study techniques, and theory work at the Lab’s Molecular Foundry; as well as data processing, simulation and analysis work at the Lab’s National Energy Research Scientific Computing Center (NERSC).

William Chueh, an assistant professor of materials science at Stanford University who also heads up the users’ association for researchers who use the ALS or are interested in using the ALS, said that the upgrade will aid his studies by improving the resolution in tracking how charged particles move through batteries and fuel cells, for example.

“I am very excited by the science that the ALS-U project will enable. Such a tool will provide insights and design rules that help us to develop tomorrow’s materials,” Chueh said.

The upgrade project is a massive undertaking that will draw upon most areas at the Lab, said ALS-U Project Director David Robin, requiring the expertise of accelerator physicists, mechanical and electrical engineers, computer scientists, beamline optics and controls specialists, and safety and project management personnel, among a long list.

Berkeley Lab’s pioneering history of innovation and achievements in accelerator science, beginning with Lab founder Ernest Lawrence’s construction of the first cyclotron particle accelerator in 1930, have well-prepared the Lab for this latest project, Robin said.

He noted the historic contribution by the late Klaus Halbach, a Berkeley Lab scientist whose design of compact, powerful magnetic instruments known as permanent magnet insertion devices paved the way for the design of the current ALS and other so-called third-generation light sources of its kind.

An interior view of the Advanced Light Source. (Credit: Berkeley Lab)

The ALS-U project will remove more than 400 tons of equipment associated with the existing ALS storage ring, which is used to circulate electrons at nearly the speed of light to generate the synchrotron radiation that is ultimately emitted as X-rays and other forms of light.

A new magnetic array known as a “multi-bend achromat lattice” will take its place, and a secondary, “accumulator” ring will be added that will enhance beam brightness. Also, several new ALS beamlines are already optimized for the high brightness and coherence of the ALS-U beams, and there are plans for additional beamline upgrades.

This 1940s photograph shows the original building that housed a 184-inch cyclotron and that now contains the ALS. (Credit: Berkeley Lab)

The iconic domed building that houses the ALS – which was designed in the 1930s by Arthur Brown Jr., the architect for San Francisco landmark Coit Tower – will be preserved in the upgrade project. The ALS dome originally housed an accelerator known as the 184-inch cyclotron.

Robin credited the ALS-U project team, with support from all areas of the Lab, in the continuing progress toward the upgrade. “They have done a tremendous job in getting us to the point that we are at today,” he said.

Witherell said, “The fact that we will have this upgraded Advanced Light Source is an enormous vote of confidence in us by the federal government and the taxpayers.”

Berkeley Lab’s ALS, Molecular Foundry, and NERSC are all DOE Office of Science user facilities.

More information:

ALS-U Overview
Transformational X-ray Project Takes a Step Forward, Oct. 3, 2016
A Brief History of the ALS

See the full article here .

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A U.S. Department of Energy National Laboratory Operated by the University of California

From European XFEL: “First European XFEL research results published”

European XFEL

From European XFEL

2018/08/28

High number of X-ray pulses per second reduces time needed for the study of biological structures.

The SPB/SFX instrument at European XFEL. Copyright: European XFEL

Just days before the first anniversary of the start of European XFEL user operation, the first results based on research performed at the facility have been published. In the journal Nature Communications, the scientists, headed by Prof. Ilme Schlichting from Max-Planck-Institute for Medical Research in Heidelberg, Germany, together with colleagues from Rutgers State University of New Jersey, USA, France, DESY and European XFEL, describe their work using the intense X-ray laser beam to determine the 3D structure of several proteins. They demonstrate, for the first time that, under the conditions used at the time of the experiment an increased number of X-ray pulses per second as produced by the European XFEL can be successfully used to determine the structure of biomolecules. As much faster data collection is therefore possible, the time needed for an experiment could be significantly shortened. The detailed determination of the 3D structure of biomolecules is crucial for providing insights into informing the development of novel drugs to treat diseases.

Prof. Ilme Schlichting said: “Our work shows that under the conditions used data can be collected at European XFEL at a rate much faster than has ever been previously possible. As the time and cost of experiments decrease, very soon many more researchers will be able to perform experiments at high repetition rate X-ray lasers. Our results are therefore of interest not only tor the fields of biology and medicine, but also physics, chemistry and other disciplines.”

Prof. Robert Feidenhans’l, managing director of European XFEL: “This fantastic result, published just weeks after the experiment itself, is a reflection of the hard work of many dedicated people. Our users as well as our staff at European XFEL, DESY and our collaborators have all ensured that everything from designing and setting up the experiment, through to data collection and publication works effectively.”

The scientists studied a mixture of three plant proteins – an enzyme known as urease, concanavalin A, and concanavalin B. At the SPB/SFX instrument (single particles, clusters and biomolecules /serial femtosecond crystallography), a jet of liquid containing a stream of tiny protein crystals was injected into the interaction chamber. The X-ray beam, consisting of series of ultra-short X-ray pulses, was fired at the jet, hitting the crystals. Where X-ray pulses interacted with the crystals, so-called diffraction patterns were captured by the detector situated behind the interaction chamber. With the help of computer algorithms, these images can be used to construct 3D models of the proteins being studied. The scientists were able to collect many thousands of images which were good enough to be able to distinguish between the three proteins, and construct 3D models of the concanavalin A and B proteins. (see also info box ‘experimental challenges’)

___________________________________________
Experimental challenges

When hit by the first pulse of the pulse train, the liquid jet delivering the sample is momentarily blown apart. It was, therefore, feared that the time between the pulses (less than a millionth of a second) would be too short for the jet to recover in time for the next pulse. Another worry was that the first pulse would produce a shockwave, that would travel along the liquid jet with such a force as to affect the crystals before they even entered the X-ray beam. This would therefore prevent subsequent pulses from measuring anything useful. Both of these fears have however been proven to be unfounded for the experimental conditions of this study, demonstrating that the European XFEL can be used at this very high pulse rate.
___________________________________________

Guest scientist Tokushi Sato working at the sample chamber of the SPB/SFX instrument. Copyright: European XFEL

The X-ray laser can generate up to 27 000 pulses per second. However, the X-ray pulses of the European XFEL X-ray beam are organized into short bursts which are separated by longer pauses with no pulses at all. If a burst lasted an entire second, it would deliver more than a million pulses – or 1.1 megahertz. Now, for the first time ever – such a rate of over one million pulses per second, or one megahertz has been reached. No other X-ray facility worldwide currently can provide such a high rate. (see also info box ‘pulse rates explained’)

___________________________________________
Pulse rates explained

At the time this experiment was carried out, European XFEL was generating 500 pulses per second. But the pulses generated by the X-ray laser are not evenly distributed and spaced throughout time. Instead they are concentrated in ten short bursts per second, known as pulse trains. The ten pulse trains with 50 pulses each are separated by a break where no pulses are delivered. Hence the 50 pulses are actually delivered within a much shorter time frame than one second. Within each pulse train, the individual pulses are extremely close together. If the pulse train lasted an entire second, it would therefore deliver more than a million pulses – or 1.1 megahertz. This is the pulse rate. Eventually European XFEL will provide 27 000 pulses a second, at a rate of more than 4 Megahertz.
___________________________________________

Dr. Adrian Mancuso, leading scientist at the SPB/ SFX instrument: “This milestone is the fruit of a lot of hard work by the SPB/SFX team and all European XFEL staff, as well as all of our early users–from more than 35 universities and labs around the world–who assisted with commissioning the SPB/SFX instrument. With these results we could now, for example, use these pulses to produce movies of molecules in motion. If we can kick start a reaction during the first few pulses of a train, we can then use the rest of the pulses to take snapshots of that reaction as it unfolds.”

Currently only five X-ray lasers world-wide produce X-rays with a short wavelength, so-called hard X-rays. Access for experiments is therefore in high demand, and the facilities are generally highly oversubscribed. Shortened experiment time thanks to an increased number of X-ray pulses as described today will enable more and more complex research projects and allow a larger number of scientists access to the brightest X-ray sources in the world.

Acknowledgement: The SFX User Consortium has provided instrumentation and personnel that has enabled this experiment. The SFX User consortium is composed of scientific partners from Germany, Sweden, the United Kingdom, Slovakia, Switzerland, Australia and the United States.

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XFEL Tunnel

XFEL Gun

The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

The outstanding characteristics of the facility are unique worldwide. Started in 2017, it will open up completely new research opportunities for scientists and industrial users.

From Brookhaven National Lab: “Novel X-Ray Optics Boost Imaging Capabilities at NSLS-II”

From Brookhaven National Lab

August 23, 2018
Rebecca Wilkin
rebeccalwilkin@gmail.com

Brookhaven Lab scientists capture high-resolution, 3-D images of thick materials more efficiently than ever before.

NSLS-II scientist Hande Öztürk stands next to the Hard X-ray Nanoprobe (HXN) beamline, where her research team developed the new x-ray imaging technique. No photo credit.

Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new approach to 3-D x-ray imaging that can visualize bulky materials in great detail—an impossible task with conventional imaging methods. The novel technique could help scientists unlock clues about the structural information of countless materials, from batteries to biological systems.

The scientists developed their approach at Brookhaven’s National Synchrotron Light Source II (NSLS-II)—a DOE Office of Science User Facility where scientists use ultra-bright x-rays to reveal details at the nanoscale. The team is located at NSLS-II’s Hard X-ray Nanoprobe (HXN) beamline, an experimental station that uses advanced lenses to offer world-leading resolution, all the way down to 10 nanometers—about one ten-thousandth the diameter of a human hair.

HXN produces remarkably high-resolution images that can provide scientists with a comprehensive view of different material properties in 2-D and 3-D. The beamline also has a unique combination of in situ and operando capabilities—methods of studying materials in real-life operating conditions. However, scientists who use x-ray microscopes have been restricted by the size and thickness of the materials they can study.

“The x-ray imaging community is still facing major challenges in fully exploiting the potential of beamlines like HXN, especially for obtaining high-resolution details from thick samples,” said Yong Chu, lead beamline scientist at HXN. “Obtaining quality, high-resolution images can become challenging when a material is thick—that is, thicker than the x-ray optics’ depth of focus.”

Now, scientists at HXN have developed an efficient approach to studying thick samples without sacrificing the excellent resolution that HXN provides. They describe their approach in a paper published in the journal Optica.

“The ultimate goal of our research is to break the technical barrier imposed on sample thickness and develop a new way of performing 3-D imaging—one that involves mathematically slicing through the sample,” said Xiaojing Huang, a scientist at HXN and a co-author of the paper.

The research team is pictured at the HXN workstation. Standing, from left to right, are Xiaojing Huang, Hanfei Yan, Evgeny Nazaretski, Yong Chu, Mingyuan Ge, and Zhihua Dong. Sitting, from left to right, are Hande Öztürk and Meifeng Lin. Not pictured: Ian Robinson.

The conventional method of obtaining a 3-D image involves collecting and combining a series of 2-D images. To obtain these 2-D images, the scientists typically rotate the sample 180 degrees; however, large samples cannot easily rotate within the limited space of typical x-ray microscopes. This limitation, in addition to the challenge of imaging thick samples, makes it nearly impossible to reconstruct a 3-D image with high resolution.

“Instead of collecting a series of 2-D projections by rotating the sample, we simply ‘slice’ the thick material into a series of thin layers,” said lead author Hande Öztürk. “This slicing process is carried out mathematically without physically modifying the sample.”

Their technique benefits from HXN’s special optics, called Multilayer Laue lenses (MLLs), which are engineered to focus x-rays into a tiny point. These lenses create favorable conditions for studying thinner slices of thick materials, while also reducing the measurement time.

“HXN’s unique MLLs have a high focusing efficiency, so we can spend much less time collecting the signal we need,” said Hanfei Yan, a scientist at HXN and a co-author of the paper.

By combining the MLL optics and the multi-slice approach, the HXN scientists were able to visualize two layers of nanoparticles separated by only 10 microns—about one tenth the diameter of a human hair—and with a resolution 100 times smaller. Additionally, the method significantly cut down the time needed to obtain a single image.

“This development provides an exciting opportunity to perform 3-D imaging on samples that are very difficult to image with conventional methods—for example, a battery with a complicated electrochemical cell,” said Chu. He added that this approach could be very useful for a wide variety of future research applications.

This study was supported by Brookhaven Lab’s Laboratory Directed Research and Development program. Operations at NSLS-II are supported by DOE’s Office of Science.

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BNL NSLS-II

BNL NSLS II

BNL RHIC Campus

BNL/RHIC Star Detector

BNL RHIC PHENIX

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

From SLAC National Accelerator Lab: “How SLAC’s ‘electronics artists’ enable cutting-edge science”

From SLAC National Accelerator Lab

August 23, 2018
Manuel Gnida

A team of electrical designers develops specialized microchips for a broad range of scientific applications, including X-ray science and particle physics.

When Angelo Dragone talks about designing microchips for cutting-edge scientific applications at the Department of Energy’s SLAC National Accelerator Laboratory, it becomes immediately clear that it’s at least as much of an art form as it is research and engineering. Similar to the way painters follow an inspiration, carefully choose colors and place brush stroke after brush stroke on canvas, he says, electrical designers use their creative minds to develop the layout of a chip, draw electrical components and connect them to build complex circuitry.

This illustration shows the layout of an application-specific integrated circuit, or ASIC, at an imaginary art exhibition. Members of the Integrated Circuits Department of SLAC’s Technology Innovation Directorate artfully design ASICs for a wide range of scientific experiments. (Greg Stewart/SLAC National Accelerator Laboratory)

A production wafer of ASICs for an ePix10k X-ray camera. ASICs are cut from the wafer and assembled on carrier boards. (Dawn Harmer/SLAC National Accelerator Laboratory)

Dragone leads a team of 12 design engineers who develop application-specific integrated circuits, or ASICs, for X-ray science, particle physics and other research areas at SLAC. Their custom chips are tailored to extract meaningful features from signals collected in the lab’s experiments and turn them into digital signals that can be further analyzed.

Like the CPU in your computer at home, ASICs process information and are extremely complex, with a 100 million transistors combined on a single chip, Dragone says. “However, while commercial integrated circuits are designed to be good at many things for broad use in all kinds of applications, ASICs are optimized to excel in a specific application.”

For SLAC applications this means, for example, that they perform well under harsh conditions, such as extreme temperatures at the South Pole and in space, as well as high levels of radiation in particle physics experiments. In addition, ultra-low-noise ASICs are designed to process signals that are extremely faint.

Pietro Caragiulo, a senior member of Dragone’s team, says, “Every chip we make is specific to the particular environment in which it’s used. That makes our jobs very challenging and exciting at the same time.”

From fundamental physics to self-driving cars

Most of the team’s ASICs are for SLAC’s core research areas in photon science and particle physics. First and foremost, ASICs are the heart of the ePix series of high-performance X-ray cameras that take snapshots of materials’ atomic fabric with the Linac Coherent Light Source (LCLS) X-ray laser.

SLAC/LCLS

“In a way, these ASICs play the same role in processing image information as the chip in your cell phone camera, but they operate under conditions that are way beyond the specifications of off-the-shelf technology,” Caragiulo says. They are, for instance, sensitive enough to detect single X-ray photons, which is crucial when analyzing very weak signals. They also have extremely high spatial resolution and are extremely fast, allowing researchers to make movies of atomic processes and study chemistry, biology and materials science like never before.

The engineers are now working on a new camera version for the LCLS-II upgrade of the X-ray laser, which will boost the machine’s frame rate from 120 to a million images per second and will pave the way for unprecedented studies that aim to develop transformative technologies, such as next-generation electronics, drugs and energy solutions.

SLAC/LCLS II projected view

“X-ray cameras are the eyes of the machine, and all their functionality is implemented in ASICs,” Caragiulo says. “However, there is no camera in the world right now that is able to handle information at LCLS-II rates.”

Exposed head of an ePix10k camera with prototype ASIC/sensors chips for X-ray science at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser. (Dawn Harmer/SLAC National Accelerator Laboratory)

In addition to X-ray applications at LCLS and the lab’s Stanford Synchrotron Radiation Lightsource (SSRL), ASICs are key components of particle physics experiments, such as the next-generation neutrino experiments nEXO and DUNE. The team is working on chips that will handle the data readout.

SLAC SSRL PEP collider map

SLAC/SSRL

FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA

SURF DUNE LBNF Caverns at Sanford Lab

“The particular challenge here is that these experiments operate at very low temperatures,” says Bojan Markovic, another senior member of Dragone’s team. nEXO will run at minus 170 degrees Fahrenheit and DUNE at an even chillier minus 300 degrees, which is far below the temperature specifications of commercial chips.

Other challenges in particle physics include exposure to high particle radiation, for instance in the ATLAS detector at the Large Hadron Collider (LHC) at CERN in Europe.

CERN/ATLAS detector

“In the case of ATLAS we also want ASICs that support a large number of pixels to obtain the highest possible spatial resolution, which is needed to determine where exactly a particle interaction occurred in the detector,” Markovic says.

SLAC’s ASICs can also be found in space. The Large Area Telescope on NASA’s Fermi Gamma-ray Space Telescope – a sensitive “eye” for the most energetic light in the universe – has 16,000 chips in nine different designs on board where they have been performing flawlessly for the past 10 years.

NASA/Fermi LAT

NASA/Fermi Gamma Ray Space Telescope

“We’re also expanding into areas that are beyond the research SLAC has traditionally been doing,” says Dragone whose Integrated Circuits Department is part of the Advanced Instrumentation for Research Division within the Technology Innovation Directorate that uses the lab’s core capabilities to foster technological advances. The design engineers are working with young companies to test their chips in a wide range of applications, including 3D sensing, the detection of explosives and driverless cars.

Members of the Integrated Circuits Department. From left: Faisal Abu-Nimeh, Camillo Tamma, Bojan Markovic, Angelo Dragone, Aseem Gupta, Aldo Pena Perez, Hussein Ali and Pietro Caragiulo. Not in the photo: Dieter Freytag, Lorenzo Rota and Umanath Kamath. (Dawn Harmer/SLAC National Accelerator Laboratory)

A creative process

But how exactly does the team develop a highly complex microchip and create its particular properties?

It all starts with a discussion in which scientists explain their needs for a particular experiment. “Our job as creative designers is to come up with novel architectures that provide the best solutions,” Dragone says.

After the requirements have been defined, the designers break the task down into smaller blocks. In the typical experimental scenario, a sensor detects a signal (like a particle passing through the detector) from which the ASIC extracts certain features (like the deposited charge or the time of the event) and converts them into digital signals which are then acquired and transported by an electronics board into a computer for analysis. The extraction block in the middle differs most from project to project and requires frequent modifications.

Once the team has an idea for how they want to do these modifications, they use dedicated computer systems to design the electronic circuits blocks, carefully choosing components to balance size, power, speed, noise, cost, lifetime and other specifications. Circuit by circuit, they draw the entire chip – an intricate three-dimensional layout of millions of electronic components and connections between them – and keep validating the design through simulations along the way.

Left: Three ASICs for an ePix10k X-ray camera mounted on a carrier board. One ASIC has a prototype sensor bonded on top for tests with X-rays. Right: Zooming into an ASIC reveals its intricate three-dimensional network of 100 million transistors and the connections between them. (Greg Stewart/SLAC National Accelerator Laboratory)

“The way we lay everything out is key to giving an ASIC certain properties,” Markovic says. “For example, the mechanical or electrical shielding we put around the ASIC components prepares the chip for high radiation levels.”

The layout is sent to a foundry that fabricates a small-scale prototype, which is then tested at SLAC. Depending on the outcome of the tests, the layout is either modified or used to produce the final ASIC. Last but not least, Dragone’s team works with other groups in SLAC’s Technology Innovation Directorate that mate the ASICs with sensors and electronics boards.

“The time it takes from the initial discussion to having a functional chip varies with the complexity of the ASIC and depends on whether we’re modifying an existing design or building a completely new one,” Caragiulo says. “The entire process can take a couple of years, with three or four designers working on it.”

For the next few years, the main driver of ASICs development at SLAC is LCLS-II, which demands X-ray cameras that can snap images at unprecedented rates. Neutrino experiments and particle physics applications at the LHC will remain another focus, in addition to a continuing effort to expand into new fields and to work with start-ups.

The future for ASICs is bright, Dragone says. “We’re seeing a general trend to more and more complex experiments, and we need to put more and more complexity into our integrated circuits,” he says. “ASICs really make these experiments possible, and future generations of experiments will always need them.”

See the full article here .

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SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From Lawrence Berkeley National Lab: “Infrared Beams Show Cell Types in a Different Light”

From Lawrence Berkeley National Lab

August 23, 2018

Glenn Robert Jr.
geroberts@lbl.gov
(510) 486-5582

Berkeley Lab scientists developing new system to identify cell differences.

From left to right: Aris Polyzos, Edward Barnard, and Lila Lovergne, pictured here at Berkeley Lab’s Advanced Light Source, are part of a research team that is developing a cell-identification technique based on infrared imaging and machine learning. (Credit: Marilyn Chung/Berkeley Lab)

By shining highly focused infrared light on living cells, scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) hope to unmask individual cell identities, and to diagnose whether the cells are diseased or healthy.

They will use their technique to produce detailed, color-based maps of individual cells and collections of cells – in microscopic and eventually nanoscale detail – that will be analyzed using machine-learning techniques to automatically sort out cell characteristics.

Using microscopic color maps to unlock cell identity

Their focus is on developing a rapid way to easily identify cell types, and features within cells, to aid in biological and medical research by providing a way to probe living cells in their native environment without harming the cells or requiring obtrusive cell-labeling techniques.

“This is totally noninvasive,” said Cynthia McMurray, a biochemist and senior scientist in Berkeley Lab’s Molecular Biophysics and Integrated Bioimaging Division who is leading this new imaging effort with Michael Martin, a physicist and senior staff scientist at Berkeley Lab’s Advanced Light Source (ALS).

LBNL/ALS

The ALS has dozens of beamlines that produce beams of intensely focused light, from infrared to X-rays, for a broad range of experiments.

“We’re looking at the signatures that define what a cell is. We’re interested in cell identity and what determines it,” McMurray said. “I’ve been involved in looking at tissue and the differences in diseased and normal states for a long time, and what I realized is that we could use these infrared beamlines at the ALS to come up with signatures for these cells.”

Researchers also plan to use the technique to identify and decipher the molecular properties of microbes and plants.

A goal of the infrared-imaging research, which builds on Berkeley Lab’s strengths in neuroscience, infrared imaging, computation, visualization, engineering, and machine learning, is to find out whether a cell’s specialization is imposed by its environment or whether it is part of the cell’s inherent identity, she said.

The research could help light a path toward controlling the specialization of cells, for example.

To verify that the technique works, the team is comparing their infrared-based images side-by-side with images captured using a more conventional imaging technique known as immunofluorescence.

Already, through unpublished research the team has found differences in the same types of brain cells taken from different locations in the brain. “On the surface they don’t look any different, but if you probe it with infrared light, something about them is different,” she said. The imaging technique can be used to show the location and variety of cell types and cell signatures present in tissue samples. “We are very interested in the interactivity of cells.”

Initiative targets disease

Long-term goals for the research are to understand disease progression at a cellular level, and to explore how stem cells transform into other cell types. “We want to watch cells differentiate. What allows cells to make the choice to be something else?” she said.

Berkeley Lab scientists received a round of seed money through the philanthropic Chan Zuckerberg Initiative DAF (CZI), an advised fund of Silicon Valley Community Foundation, to support their effort, dubbed “spectral phenotyping.”

An Aug. 8 news article in the journal Science highlighted their work and that of a larger research project called the Human Cell Atlas that aims to provide “a unique ID card for each cell type,” as well as a 3D map of how cells form tissues, and new insights into disease.

The Chan Zuckerberg Initiative, launched by Facebook founder Mark Zuckerberg and Priscilla Chan, a pediatrician and philanthropist who is married to Zuckerberg, has three focus areas: science, education, and justice and opportunity. The stated goal of the science focus is to support interdisciplinary teams in developing “science and technology that will help make it possible to cure, prevent, or manage all diseases by the end of the century.”

A key to the infrared-imaging technique, McMurray said, is that it allows cells to exist in their native environment, and doesn’t require any labels or special prepping that could damage or otherwise alter the cells.

A global focus

Martin, who is part of the infrared-based cell-imaging research, noted that the properties of infrared light produced at the ALS are rare among the world’s research institutions, and its possible applications in cell identification are largely unexplored.

The detectors at one of the ALS infrared beamlines are capable of scanning across 1,000 wavelengths for each pixel of the detector – the pixel is the smallest unit of the image – so the cell imaging can generate a large volume of data.

In designing computer algorithms to sort out cells’ differences, Martin said, “It’s not just about picking one feature. We think it’s more powerful to ask broader questions: What’s the whole suite of differences?”

By looking across a wide range of infrared wavelengths in each cell image, “Hopefully we’ll find something much deeper,” he said.

To improve infrared cell-identification to tens-of-nanometers resolution, researchers plan to adapt a synchrotron infrared nanospectroscopy (SINS) system, shown above. The system incorporates highly focused infrared light produced by the Advanced Light Source (integral to “rapid-scan FTIR” or Fourier-transform infrared spectroscopy) and a technique known as atomic force microscopy (AFM). (Credit: Berkeley Lab)

here are plans to use a new, higher-resolution infrared beamline at the ALS that could resolve cell features down to tens of nanometers (billionths of a meter), he also noted, and to develop a way to flow living cells through the infrared beam for high-throughput imaging.

While the properties of infrared light produced at the ALS are relatively unique, Martin and McMurray said it’s their hope that the cell-imaging data they generate will prove useful for researchers working with lower-power infrared-imaging tools, too.

The team’s proposal to the Chan Zuckerberg Initiative outlines a plan to develop a complete, push-button system that ultimately could be used by the broader research community.

“We want to bring all of this together to develop something that is open to the rest of the world,” Martin said.

See the full article here .

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A U.S. Department of Energy National Laboratory Operated by the University of California

From Brookhaven National Lab: “High-Caliber Research Launches NSLS-II Beamline into Operations”

From Brookhaven National Lab

August 2, 2018
Stephanie Kossman
skossman@bnl.gov

Pratt & Whitney conduct the first experiments at a new National Synchrotron Light Source II beamline.

Bruce Ravel is the lead scientist at the Beamline for Materials Measurement (BMM), a new, state-of-the-art experimental station at NSLS-II. BMM was constructed and is operated by the National Institute of Standards and Technology (NIST).

A new experimental station (beamline) has begun operations at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Brookhaven National Laboratory. Called the Beamline for Materials Measurement (BMM), it offers scientists state-of-the-art technology for using a classic synchrotron technique: x-ray absorption spectroscopy.

“There are critical questions in all areas of science that can be solved using x-ray absorption spectroscopy, from energy sciences and catalysis to geochemistry and materials science,” said Bruce Ravel, a physicist at the National Institute of Standards and Technology (NIST), which constructed and operates BMM through a partnership with NSLS-II.

X-ray absorption spectroscopy is a research technique that was developed in the 1980s and, since then, has been at the forefront of scientific discovery.

“The reason we’ve used this technique for 40 years and the reason why NIST built the BMM beamline is because it adds a great value to the scientific community,” Ravel explained.

The first group of researchers to conduct experiments at BMM came from jet engine manufacturer Pratt & Whitney. Senior Engineer Chris Pelliccione and colleagues used BMM to study the chemistry of jet engines.

Pratt & Whitney Senior Engineer Chris Pelliccione (left) with NIST’s Bruce Ravel (right) at BMM’s workstation.

“We investigated the ceramic thermal barrier coatings used in jet engines,” Pelliccione said. “Due to the extreme temperature and pressure that these components operate in, the data from this investigation will help us design for durability. Our experiment at BMM was designed to understand some of the chemical interactions in more detail for today’s programs as well as tomorrow’s new breakthroughs.”

Coupling BMM’s advanced design with NSLS-II’s ultra-bright x-ray light, the scientists at Pratt & Whitney were able to determine the spatial distribution of chemical interactions in the coating.

The Beamline for Materials Measurement (BMM) at the National Synchrotron Light Source II.

“We needed a beamline with a small focused beam size and high flux to obtain the quality of data we were interested in,” Pelliccione said. “BMM offers both of these capabilities and our measurements were very successful. We were able to extract valuable information about the coatings that is not easily accessible through other research techniques.”

Pratt & Whitney conducted its experiments at BMM during the final “commissioning” stage of the beamline, and the high-caliber research launched BMM into general operations.

“We hope to take advantage of the fantastic beamlines that are already up and running at NSLS-II, as well as those that are coming online soon,” Pelliccione concluded.

Ravel added, “It was incredibly gratifying to send Pratt & Whitney home with such valuable data. It is a very important part of NIST’s mission to work with companies and to promote U.S. innovation and industrial competitiveness.”

More about NIST and NSLS-II

NSLS-II is one of the world’s newest and most advanced synchrotron light sources. NSLS-II currently has 26 beamlines in operations and three in commissioning and construction phases. The facility has space for an additional 30 beamlines to be constructed. With the goal of “seeing” detailed views of chemical reactions, NSLS-II partnered with NIST to develop and operate three beamlines—SST-1, SST -2 and BMM—at NSLS-II.

See the full article here .

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BNL RHIC Campus

BNL/RHIC Star Detector

BNL RHIC PHENIX

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

From Brookhaven Lab: “New Magnetic Materials Overcome Key Barrier to Spintronic Devices”

From Brookhaven National Lab

August 1, 2018
Justin Eure
justin.eure@gmail.com

Custom-engineered structure enables unprecedented control and efficiency in otherwise impervious antiferromagnetic materials.

Brookhaven scientists Derek Meyers (left) and Mark Dean (right) using their x-ray diffractometer to characterize the atomic structure of the samples for the experiment.

Consider the classic, permanent magnet: it both clings to the refrigerator and drives data storage in most devices. But another kind of impervious magnetism hides deep within many materials—a phenomenon called antiferromagnetism (AFM)—and is nearly imperceptible beyond the atomic scale.

Now, a team of scientists just developed an unprecedented material that cracks open this hermetic magnetism, confirming a decades-old theory and creating new engineering possibilities. The team, led by the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and the University of Tennessee, designed AFM materials with spin—the quantum mechanism behind all magnetism—that can be easily controlled with minimal energy.

“Material synthesis finally caught up to theory, and we found a way around the most prohibitive quantum quirks of exploiting antiferromagnetism,” said Brookhaven Lab physicist and study corresponding author Mark Dean. “This work dives deeper into the underpinnings of magnetism and creates new possibilities for spin-based technologies.”

The results, published this summer in Nature Physics, could dramatically enhance the emerging field of spintronics, where information is coded into the directional spin of electrons.

“The real surprise was just how well this synthetic material functioned right out of the gate,” said coauthor and Brookhaven Lab scientist Derek Meyers. “Not only can we manipulate this remarkable spin, but we can do it with extreme efficiency.”

Twisting electron spins

The spin orientation of electrons within atoms and can be visualized as simple arrows pointing in well-defined directions.

“In ferromagnets, these spins are all aligned,” said University of Tennessee professor and corresponding author Jian Liu. “They all point up or down, creating an external magnetic effect—like refrigerator magnets—that can be flipped when an external field is applied.”

This flipping process powers the writing of digital information on most data storage devices, among other things.

“Antiferromagnets are much stranger,” Meyers said. “Every arrow points in the opposite direction of its nearest neighbor, alternating up-down-up-down across the material. And it stays synchronized, such that one flip reverses all the others. That means, essentially, they all cancel each other out.”

This perfect balance makes AFM spin notoriously impervious to manipulation, requiring too much energy to make the process useful. So the scientists introduced a little imperfection.

“If we tilt, or cant, the spins, we create asymmetry and make the material more susceptible to influence,” Dean said. “External magnets can couple with the spin. But prior to this work, there was a built-in compromise to this approach.”

While the canted spin can “feel” magnetic fields, the directional freedom is lost—the spins can no longer change direction.

Gears in a quantum clock

Imagine adjacent electrons as gears in a clock: the teeth all fit together to move in tandem and preserve precise relationships. Tilting the spin realigns those gears, almost as if they abruptly began to rotate in opposite directions and locked in place. How, then, to set those gears back in motion?

“We followed a long-standing theory to create an unprecedented material that both cants the spin and keeps it free to rotate, which we would call preserving isotropy,” said first author Lin Hao of the University of Tennessee. “To do this, we designed a structure that cancels out those competing anisotropies, or directional asymmetries.”

In a way, they built another gear into their antiferromagnetic clock. The extra gear slots in between the jammed electron spins, giving them a balance and space that would never naturally occur. The “gear” is actually a hidden symmetry called SU(2), a mathematical term describing the isotropic freedom.

Layered crystalline lattice

“The extreme sophistication of two-dimensional materials synthesis made this possible,” Liu said. “We grew a crystalline lattice with fully customized geometries to prevent the spins from locking—this is engineering with almost quantum precision.”

The team used pulsed laser deposition to create a lattice composed of strontium, iridium, titanium, and oxygen. In this way, atomically thin layers could be stacked in different configurations to induce artificial and much desired properties.

In this work, the team exploited special “gearing” properties of the iridium oxide layers in which the spins can be tilted, but remain free to respond to an applied magnetic field.

The collaboration turned to the Advanced Photon Source (APS)—a DOE Office of Science User Facility at DOE’s Argonne National Laboratory—to confirm the crystal structure of the material. Using advanced resonant x-ray diffraction, the scientists revealed details of both the lattice and the electron configuration.

ANL/APS

“Because of the precision possible at the APS, we were able to see the fruits of the difficult synthesis process,” Meyers said. “We saw the precise layered structure we wanted, but the real test was in the magnetic function.”

Again turning to APS, the team used x-ray scattering to measure the antiferromagnetic order, the alignment of the spins within the material.

“We were pleased to see our canted spins retain the freedom of motion we expected,” Dean said. “It’s rare and thrilling to see things come together so seamlessly. And crucially, we proved that manipulating that AFM spin required very little energy—a must for spintronic applications.”

Toward superior storage

Traditional magnetic devices have an intrinsic limit: packed too closely together, ferromagnetic materials affect each other. This translates into a functional cap on data density beyond which the spins become corrupted. However, AFM materials—or discrete AFM crystals in this instance—exert no external influence.

“We can, in theory, pack much more information into devices by manipulating antiferromagnetic spin,” Dean said. “That’s part of the promise of spintronics.”

The combination of low energy input—think efficient writing of data—and density make the new material an ideal candidate for investment.

“The obstacle right now has to do with scale,” Liu said. “This is a first-of-its-kind material, so no industrial-scale process exists. But this is how it starts, and the demand for this kind of functionality might rapidly move this innovation into applications.”

Additional collaborating institutions include Charles University in Prague.

See the full article here .

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BNL RHIC Campus

BNL/RHIC Star Detector

BNL RHIC PHENIX

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

From European XFEL: “Third light source generates first X-ray light”

European XFEL

From European XFEL

All three light sources, SASE 1,2 and 3, are now operational and have been successfully run in parallel for the first time. Copyright: DESY/European XFEL.

European XFEL starts operation of its third light source, exactly a year after the first X-ray light was generated in the European XFEL tunnels.

DESY European XFEL

The third light source will provide light for the MID (Materials Imaging and Dynamics) and HED (High Energy Density Science) instruments scheduled to start user operation in 2019.

The MID instrument at European XFEL, currently under construction

All three light sources, successfully run in parallel for the first time on the anniversary of European XFEL’s first light, will eventually provide X-rays for at least six instruments. At any one time, three of these six instruments can simultaneously receive X-ray beam for experiments. “The operation of the third light source, and the generation of light from all sources in parallel, are important steps towards our goal of achieving user operation on all six instruments” said European XFEL Managing Director Robert Feidenhans’l. “I congratulate and thank all those involved in this significant accomplishment. It was a tremendous achievement to get all three light sources to generate light within the space of one year.”

XFEL Undulator

To generate flashes of X-ray light, electrons are first accelerated to near the speed of light before they are moved through long rows of magnets called undulators. The alternating magnetic fields of these magnets force the electrons on a slalom course, causing the electrons to emit light at each turn. Over the length of the undulator, the produced light interacts back on the electron bunch, thereby producing a particularly intense light. This light accumulates into intensive X-ray flashes. This process is known as ‘self-amplified spontaneous emission’, or SASE. European XFEL has three SASE light sources. The first one, SASE 1, taken into operation at the beginning of May 2017, provides intense X-ray light to the instruments SPB/SFX (Single Particles, Clusters and Biomolecules and Serial Femtosecond Crystallography) and FXE (Femtosecond X-ray Experiments), the first instruments available for experiments and operational since September 2017. The second light source, SASE 3, was successfully taken into operation in February 2018 and will provide light for the instruments SQS (Small Quantum Systems) and SCS (Spectroscopy and Coherent Scattering), scheduled to start user operation in November 2018. SASE 1 and SASE 3 can be run simultaneously – high speed electrons first generate X-ray light in SASE 1, before being used a second time to produce X-ray light of a longer wavelength in SASE 3. Now, exactly a year after the first laser light was generated in the European XFEL tunnels, the third light source, SASE 2, is operational. SASE 2 will generate X-ray light for the MID (Materials Imaging and Dynamics) and HED (High Energy Density Science) instruments scheduled to start user operation in 2019. The MID instrument will be used to, for example, understand how glass forms on an atomic level, and for the study of cells and viruses with a range of imaging techniques. The HED instrument will enable the investigation of matter under extreme conditions such as that inside exoplanets, and to investigate how solids react in high magnetic fields.

DESY and European XFEL staff and scientists have worked hard over the last year to ensure the timely start of operation of all three light sources, and have also continually improved the parameters of the X-ray beam and instruments. Since the first users arrived in September 2017, the number of X-ray pulses available for experiments has been increased from 300 to 3000 per second for the next experiments, scheduled from August to October 2018. At full capacity, the European XFEL is expected to produce 27,000 pulses per second and DESY and European XFEL teams are working towards achieving this rate in test conditions during the next few months. In addition, the construction and commissioning of the remaining four instruments continues this year. Once MID and HED start operation in 2019, European XFEL will have a total of six experiment stations available for users, running from the three light sources.

Graphic showing the layout of the European XFEL tunnels, three SASE undulators and the instruments. Copyright: European XFEL

Since the start of user operation in September 2017, European XFEL has hosted over 500 researchers in international and interdisciplinary teams for experiments on the first two instruments. SPB/SFX and FXE share the X-ray beam generated in SASE1, each using the beam for alternate 12 hours per day during an experiment. Each user group generally has five days of beamtime. For the next round of experiments due to start in August, 61 proposals were received from which twelve experiments, six per instrument (SPB/SFX and FXE), will be granted.

A next call for user proposals for experiment time, now at all six instruments, will open shortly.

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XFEL Tunnel

XFEL Gun

The Hamburg area will soon boast a research facility of superlatives: The European XFEL will generate ultrashort X-ray flashes—27 000 times per second and with a brilliance that is a billion times higher than that of the best conventional X-ray radiation sources.

The outstanding characteristics of the facility are unique worldwide. Started in 2017, it will open up completely new research opportunities for scientists and industrial users.

From SLAC Lab: “X-Ray Experiment Confirms Theoretical Model for Making New Materials”

From SLAC Lab

July 2, 2018
Glennda Chui

In an experiment at SLAC, scientists loaded ingredients for making a material into a thin glass tube and used X-rays (top left) to observe the phases it went through as it was forming (shown in bubbles). The experiment verified theoretical predictions made by scientists at Berkeley Lab with the help of supercomputers (right). (Greg Stewart/SLAC National Accelerator Laboratory)

By observing changes in materials as they’re being synthesized, scientists hope to learn how they form and come up with recipes for making the materials they need for next-gen energy technologies.

Over the last decade, scientists have used supercomputers and advanced simulation software to predict hundreds of new materials with exciting properties for next-generation energy technologies.

Now they need to figure out how to make them.

To predict the best recipe for making a material, they first need a better understanding of how it forms, including all the intermediate phases it goes through along the way – some of which may be useful in their own right.

Now experiments at the Department of Energy’s SLAC National Accelerator Laboratory have confirmed the predictive power of a new computational approach to materials synthesis. Researchers say that this approach, developed at the DOE’s Lawrence Berkeley National Laboratory, could streamline the creation of novel materials for solar cells, batteries and other sustainable technologies.

“In the last 10 years, computational scientists have gotten really good at predicting the properties of new materials, but not so good at telling experimentalists like me how to make them,” said Michael Toney, a distinguished staff scientist at SLAC. “The theoretical framework developed at Berkeley Lab can help guide us in thinking about ways to synthesize and test these promising materials.”

This team described their findings June 29 in Nature Communications.

Metastable Materials

“Most theoretical approaches are great for predicting the endpoints of a reaction – what chemicals you start with, and what material you get at the end,” said study co-author Laura Schelhas, an associate staff scientist with SLAC’s Applied Energy Program. “But other interesting materials that form along the reaction pathway are often overlooked.”

These intermediate materials are said to exist in a state of metastability.

“Materials always want to be in their lowest-energy phase or ground state,” Schelhas explained. “Materials in a metastable state are higher in energy and will eventually transition to the more stable ground state. A diamond, for example, is a metastable state of carbon that will revert to its ground state, graphite, over millions of years.”

During synthesis, materials can crystallize into a series of metastable phases – some lasting only a few minutes, others persisting for hours. Some of these phases have properties that are potentially useful for technological applications. Others may block the formation of a material you want to make. Scientists want to isolate the useful phases and avoid creating the undesirable ones.

Co-authors Wenhao Sun and Gerbrand Ceder at Berkeley Lab and Daniil Kitchaev of the Massachusetts Institute of Technology recently developed a theoretical model to predict which metastable phases a material will form during synthesis.

“The key insight is to consider influences other than temperature and pressure that can affect a material’s formation,” Sun said. “For example, at a very small scale, surface energy is important, and impurities that materials take up from the surrounding environment can stabilize some types of crystalline structures. We developed a theory to quantify how these factors govern the formation of metastable phases, and then worked with SLAC to design an experiment to test it.”

The experiment, conducted at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), focused on manganese oxide, a compound whose formation can involve a variety of metastable crystalline structures. Some of these metastable structures are useful for battery applications or catalysis.

SLAC/SSRL

Schematic representation of remnant metastability in a crystallization pathway. a Free-energy of three phases (supersaturated solution (gray), M (green), S (blue)) as a function of the surface-area-to-volume ratio, 1/R (R is a particle radius). The gray line corresponds to the free-energy of a supersaturated solution, green is a metastable phase M that is size-stabilized by a low surface energy (given by the slope), and blue is the bulk equilibrium phase S, with high surface energy. b Phase diagram in the 1/R axis created from the projection of lowest free-energy phases. c A multistage crystallization pathway (red arrow in a ) proceeds downhill in energy, but phase transformations are limited by nucleation. Crystal growth of M prior to the induction of S means M can grow into a size-regime where phase M is metastable. S will then nucleate, and quickly grow by consuming M via dissolution-reprecipitation. The characteristic length scale of size-driven phase transitions lies in the 2 nm–50 nm range. Nature Communications

“Although manganese oxide has been widely studied, we still don’t have a good understanding of how to make specific metastable phases of the material,” Toney said. “Figuring out why certain recipes favor certain metastable structures will help us predict recipes for synthesizing not just this material, but others as well.”

Theory vs. Experiment

Sun and Schelhas designed an experiment to carefully manipulate a single ingredient in a recipe for making manganese oxide and track its effect on the formation of metastable crystals.

SLAC scientists led by postdoctoral researcher Bor-Rong Chen used powerful X-ray beams at SSRL to observe the chemical reaction as it happened.

“It’s pretty simple,” Schelhas said. “We load up manganese salts and other reaction materials into a small glass capillary, seal it and heat it. Then we shoot X-rays through the capillary while the reaction is occurring and watch the signal that reflects off the crystals. That signal allows us to determine the atomic structure of each metastable phase as it forms.”

At first, the metastable phases identified by X-ray diffraction didn’t seem to match the theoretical predictions, Chen said.

“We worked with the theorists at Berkeley Lab to retool the model,” she said, “and arrived at some explanations for why certain metastable phases might be skipped in a reaction, or why they might persist longer than we anticipated.”

To continue developing their understanding of synthesis, the researchers plan to conduct experiments on more complicated materials.

“This work marks only the initial steps in a much longer journey towards a predictive theory of materials synthesis,” Sun said. “Our goal is to build a powerful toolkit to design recipes for making exactly the materials we want.”

The team also found that they could stop the reaction at the point where a metastable material has formed, which will make it possible to test those materials for desirable properties in future studies, Schelhas said.

“We’re starting to push science into a new space in terms of understanding how you go about synthesis,” she added. “Predictive models have the potential to profoundly alter the way that materials design is done. That could greatly speed up the adoption of more advanced materials in areas like photovoltaics, batteries, thermoelectrics and a whole host of other sustainable technologies.”

Other co-authors of the study are from the Colorado School of Mines and the DOE’s National Renewable Energy Laboratory.

SSRL is a DOE Office of Science user facility. Funding for this work came from the Center for Next Generation of Materials Design, an Energy Frontier Research Center led by DOE’s National Renewable Energy Laboratory and funded by the DOE Office of Science.

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SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.