‘A day in the light’ Videos highlight how scientists use light in experiment

In recognition of the International Day of Light (@IDL2019) on May 16, the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) is highlighting how scientists use light in laboratory experiments. From nanolasers and X-ray beams to artificial photosynthesis and optical electronics, Berkeley Lab researchers tap into light’s many properties to drive a range of innovative R&D.
In the three videos displayed below, you will learn how light drives the science of Berkeley Lab’s Advanced Light Source (ALS), a synchrotron that produces many forms of light beams. These light beams are customized to perform a variety of experimental techniques for dozens of simultaneous experiments conducted by researchers from across the nation and around the world.

> Read more on the Advanced Light Source at Berkley Lab website

Image: Shambhavi Pratap, ALS Doctoral Fellow in Residence and a Ph.D. student at the Technical University of Munich, discusses how she studies thin-film solar energy materials using X-rays at the ALS.
Credit: Marilyn Chung/Berkeley Lab

 

Improving engine performance and fuel efficiency

A study conducted in part at the Canadian Light Source (CLS) at the University of Saskatchewan suggests reformulating lubricating oils for internal combustion engines could significantly improve not only the life of the oil but the life of the engine too.
Dr. Pranesh Aswath with the Department of Materials Science and Engineering at the University of Texas at Arlington and his research colleagues focused on the role soot plays in engine wear, and its effect on the stability of engine oil.
He described the research as “one piece of a broader story we’re trying to write” about how the reformulation of engine oils can reduce emissions, decrease wear and increase the longevity of engines.
Soot is a carbon-based material that results from incomplete combustion of fuel in an internal combustion engine, he explained. The soot ends up in crankcase oil where it is trapped by additives, but that leads to reduced engine efficiency and a breakdown of lubricating oil.

>Read more on the Canadian Light Source website

17 meter long detector chamber delivered to CoSAXS

The experimental techniques used at the CoSAXS beamline will use a huge vacuum vessel with possibilities to accommodate two in-vacuum detectors in the SAXS/WAXS geometry.

A major milestone was reached for the CoSAXS project when this vessel was recently delivered, installed and tested.
The main method that will be used at the CoSAXS beamline is called Small Angle X-ray Scattering (SAXS). By detecting the scattered rays coming from the sample at shallow angles, less than 4° typically, it is possible to learn about the size, shape, and orientation of the small building blocks that make up different samples and how this structure gives these materials their properties. The materials to be studied can come from various sources and in diverse states, for example, plastics from packaging, food and how it is processed or proteins in solution which can be used as drugs.
The “co” in CoSAXS stands for coherence, a quality of the synchrotron light optimized at the MAX IV machine, that loosely could be translated as laser-likeness. In the specific case of X-ray Photon Correlation Spectroscopy (XPCS), it lets the researchers not only measure the structure of the building blocks in the sample but also their dynamics – how they change in time.

>Read more on the MAY IV Laboratory website

Research on sand near Hiroshima shows fallout debris from A-Bomb blast

X-ray studies at Berkeley Lab provide evidence for source of exotic assortment of melt debris

Mario Wannier, a career geologist with expertise in studying tiny marine life, was methodically sorting through particles in samples of beach sand from Japan’s Motoujina Peninsula when he spotted something unexpected: a number of tiny, glassy spheres and other unusual objects.
Wannier, who is now retired, had been comparing biological debris in beach sands from different areas in an effort to gauge the health of local and regional marine ecosystems. The work involved examining each sand particle in a sample under a microscope, and with a fine brush, separating particles of interest from grains of sediment into a tray for further study.

>Read more on the Advanced LIght Source at L. Berkeley Lab website

Image: Researchers collected and studied beach sands from locations near Hiroshima including Japan’s Miyajima Island, home to this torii gate, which at high tide is surrounded by water. The torii and associated Itsukushima Shinto Shrine, near the city of Hiroshima, are popular tourist attractions. The sand samples contained a unique collection of particles, including several that were studied at Berkeley Lab and UC Berkeley.
Credit: Ajay Suresh/Wikimedia Commons

Nanometre gaps can crystallise liquids

X-ray examination shows surprising coexistence of liquid and crystalline form.

Very narrow gaps make liquids crystallise partially. X-ray investigations at DESY show that in gaps just a few molecule diameters wide both, liquid and crystal properties of a material can exist at the same time. The observation of this coexistence is important for all liquids in very small cavities and thus also for the study of friction (tribology). The team led by DESY researchers Milena Lippmann and Oliver Seeck presents the research in The Journal of Physical Chemistry Letters.
It was already known that liquids form atomically thin layers at an interface, such as the bottom or wall of a vessel. At the interface, the liquid is therefore not as disordered as in the volume. A relatively well-ordered layer of molecules of the liquid forms directly on the wall, on top of which a further layer is formed that is somewhat less orderly, on top of which a layer is even less orderly, until after about four to five layers the liquid is disordered.
“Despite this layering, the liquid remains liquid – the chemistry and physics of the layer do not change fundamentally,” explains Seeck. “An interesting situation arises if two smooth interfaces are brought together to a nanometre distance with a liquid between them.” One nanometre is one millionth of a millimetre. This brings the distance into the realm of molecule sizes. Depending on the specific liquid, its molecules can have a diameter of half a nanometre, for example.

>Read more on the PETRA III at DESY website

Image: Experimental set-up: In a diamond anvil cell, liquid is confined to a few nanometres narrow gap (centre). In this environment, layers and crystallisation coexist, as the X-ray investigation has shown.
Credit: DESY, Milena Lippmann

Coherent soft x-ray pulses from an echo-enabled free-electron laser

The free-electron laser (FEL) FERMI is a unique facility, providing users with laser-like pulses in the XUV spectral range. At FERMI, the generation of highly coherent pulses, with tunable spectro-temporal properties, relies on the so-called high-gain harmonic generation (HGHG) technique. In the latter, a (single) infrared seed laser is used to shape the electron-beam properties and trigger the amplification process. Amplification occurs at one selected harmonic, h, of the seed. However, in HGHG, the seed energy required to prepare the electron beam for FEL emission becomes larger and larger for higher harmonics (i.e., shorter FEL wavelengths). For high harmonics, the resulting strong electron-beam energy modulation reduces the FEL gain, limiting the scheme to h<15 (wavelengths of about 10-20 nm) for a single HGHG scheme, or to h of the order of 60-70 (i.e., 4-5 nm), in case of two-stage HGHG. Moreover, at such high h, the sensitivity to the shape of the electron-beam phase space becomes critical and may severely affect the FEL radiation in terms of longitudinal coherence, pulse energy, and shot-to-shot stability. In addition, the HGHG scheme cannot cover the whole harmonic range, as the final harmonic number is a product between the harmonic numbers of the individual stages. Last, but not least, the two-stage setup uses a relatively large portion of the e-beam to accommodate the double seeding process, which makes the implementation double-pulse operation difficult.
The drawbacks of the two-stage HGHG can be overcome by using a recently proposed technique called echo-enabled harmonic generation (EEHG), where the electron-beam is shaped using two seed lasers to enable FEL emission at high harmonics. The method requires a much weaker energy modulation compared to HGHG and is also intrinsically less sensitive to the initial electron-beam imperfections, making it a strong candidate for producing highly stable, nearly fully coherent, and intense FEL pulses, down to soft x-ray wavelengths.

>Read more on the FERMI at Elettra website

Image:  The EEHG scheme together with the e-beam phase space at different stages of the evolution. The 1st seed laser with a wavelength λ1 imprints a sinusoidal energy modulation with an amplitude ΔE<3σE,  σE is the initial uncorrelated energy spread, onto the relativistic e-beam in the 1st modulator. After passing through a strong 1st chicane, the electrons with different energies move relative to each other, resulting in a striated phase space with multiple energy bands. Importantly, the energy spread within a single band is much smaller than σE. The electrons then pass through the 2nd modulator, where their energy is again periodically modulated using a 2nd seed laser with λ2λ1 and ΔE2≈ΔE1. After traversing a weaker 2nd chicane, the e-beam phase space is rotated, transforming the sinusoidal energy modulation into a periodic density modulation, with high-frequency components. As the energy spread within a single band is much smaller than σE, only a moderate ΔE2 is required to reach very high harmonics. The e-beam is then injected into the radiator, tuned to emit light at a high harmonic of the 2nd seed laser.

New material also reveals new quasiparticles

Researchers at PSI have investigated a novel crystalline material that exhibits electronic properties that have never been seen before.

It is a crystal of aluminum and platinum atoms arranged in a special way. In the symmetrically repeating unit cells of this crystal, individual atoms were offset from each other in such a way that they – as connected in the mind’s eye – followed the shape of a spiral staircase. This resulted in novel properties of electronic behaviour for the crystal as a whole, including so-called Rarita-Schwinger fermions in its interior and very long and quadruple topological Fermi arcs on its surface. The researchers have now published their results in the journal Nature Physics.

Researchers at the Paul Scherrer Institute PSI have found a new kind of quasiparticle. Quasiparticles are states in material that behave in a certain way like actual elementary particles. The two physicists William Rarita and Julian Schwinger had predicted this type of quasiparticles in 1941, which came to be known as Rarita-Schwinger fermions. Exactly these have now been detected experimentally for the first time – thanks in part to measurements at the Swiss Synchrotron Light Source SLS at PSI. “As far as we know, we are – simultaneously with three other research groups – among the first to see Rarita-Schwinger fermions”, says Niels Schröter, a researcher at PSI and first author of the new study.

>Read more on the Swiss Light Source at PSI website.

Image: Niels Schröter (left) and Vladimir Strocov at their experimental station in the Swiss Light Source SLS at PSI.
Credit: Paul Scherrer Institute/Mahir Dzambegovic

Taiwan-Germany experimental facility

National Synchrotron Radiation Research Center (NSRRC) announces that a new, state-of-the-art experimental facility – TPS 45A Submicron Soft X-ray Spectroscopy Beamline, is officially opened. As one of the beamlines at the Taiwan Photon Source (TPS), it delivers soft X-ray with high brilliance, low emittance, and ultra-high spectra resolution, which is ideal for studying and developing novel materials, such as superconducting, nano and magnetic materials.
The ceremony was addressed by Deputy Minister Yu-Chin Hsu of the Ministry of Science and Technology (MOST), Director Gwo-Huei Luo of NSRRC, Chien-Te Chen (member of the NSRRC Board of Director), Director Liu Hao Tjeng of Max Planck Institute for Chemical Physics of Solids (MPI CPfS), Vice President Chii-dong Ho of Tamkang University (TKU), Director Thomas Prinz of German Institute Taipei (DIT), and Peilan Tung of German Academic Exchange Service (DAAD).

>Read more on the NSRRC website

Image: Grand opening, ribbon cutting ceremony.

New approach for solving protein structures from tiny crystals

Technique opens door for studies of countless hard-to-crystallize proteins involved in health and disease

Using x-rays to reveal the atomic-scale 3-D structures of proteins has led to countless advances in understanding how these molecules work in bacteria, viruses, plants, and humans—and has guided the development of precision drugs to combat diseases such as cancer and AIDS. But many proteins can’t be grown into crystals large enough for their atomic arrangements to be deciphered. To tackle this challenge, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and colleagues at Columbia University have developed a new approach for solving protein structures from tiny crystals.

The method relies on unique sample-handling, signal-extraction, and data-assembly approaches, and a beamline capable of focusing intense x-rays at Brookhaven’s National Synchrotron Light Source II (NSLS-II)—a DOE Office of Science user facility—to a millionth-of-a-meter spot, about one-fiftieth the width of a human hair.

>Read more on the NSLS-II at Brookhaven Lab website

Image: Wuxian Shi, Martin Fuchs, Sean McSweeney, Babak Andi, and Qun Liu at the FMX beamline at Brookhaven Lab’s National Synchrotron Light Source II, which was used to determine a protein structure from thousands of tiny crystals.

Synchrotron techniques allow geologists to study the surface of Mars

State-of-the-art imaging uncovers the exciting life history of an unusual Mars meteorite

With human and sample-return missions to Mars still on the drawing board, geologists wishing to study the red planet rely on robotic helpers to collect and analyse samples. Earlier this year we said goodbye to NASA’s Opportunity rover, but Insight landed in November 2018, and several space agencies have Mars rover missions on their books for the next few years. But while we’re working on ways to bring samples back from Mars, geologists can study Martian meteorites that have been delivered to us by the forces at play in the Solar System. Earth is bombarded by tonnes of extraterrestrial material every day. Most of it comes from Jupiter Family Comets and the asteroid belt, and much of it burns up in the atmosphere or lands in the oceans, but meteorites from the Moon and Mars do make it to Earth’s surface. In research published in Geochimica et Cosmochimica Acta, scientists used a battery of synchrotron techniques to investigate a very unusual Martian meteorite, whose eventful life story offers some insights to the geological history of Mars.

>Read more on the Diamond Light Source website

Image: BSE image with locations for XANES/XRD and XRF map.

New materials for the reduction of vehicle pollution

Research develops nanostructured material with high oxygen storage and release capacity for the improvement of catalytic converters

Complete combustion of both fossil and biofuels generates carbon dioxide (CO2) and water as final products. However, incomplete combustion of these substances can occur in automobile engines, generating important pollutants such as carbon monoxide (CO), hydrocarbons, and nitrogen oxides (such as NO and NO2).
To reduce the emission of these toxic substances, an equipment called a catalytic converter is used in the exhaust of vehicles. Materials called catalysts promote and accelerate chemical reactions without being consumed during the process. They retain on their surface the reactant molecules, weakening the bonds between the atoms and causing the pollutants to be converted into less harmful gases.
The action of the catalytic converter happens in three stages. The first stage converts the nitrogen oxides into nitrogen (N2) and oxygen (O2) gases. The second stage breaks down bonds of unburnt hydrocarbons and carbon monoxide, turning them into CO2. Finally, the third stage has an oxygen sensor to regulate the intake of air and fuel to the engine, so that the amount of oxygen is always close to the most efficient for the different reactions.

>Read more on the Brazilian Light Laboratory (LNLS) website

New lens system for brighter, sharper diffraction images

Researchers from Brookhaven Lab designed, implemented, and applied a new and improved focusing system for electron diffraction measurements.

To design and improve energy storage materials, smart devices, and many more technologies, researchers need to understand their hidden structure and chemistry. Advanced research techniques, such as ultra-fast electron diffraction imaging can reveal that information. Now, a group of researchers from the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new and improved version of electron diffraction at Brookhaven’s Accelerator Test Facility (ATF)—a DOE Office of Science User Facility that offers advanced and unique experimental instrumentation for studying particle acceleration to researchers from all around the world. The researchers published their findings in Scientific Reports, an open-access journal by Nature Research.
Advancing a research technique such as ultra-fast electron diffraction will help future generations of materials scientists to investigate materials and chemical reactions with new precision. Many interesting changes in materials happen extremely quickly and in small spaces, so improved research techniques are necessary to study them for future applications. This new and improved version of electron diffraction offers a stepping stone for improving various electron beam-related research techniques and existing instrumentation.

>Read more on the NSLS-II at Brookhaven Lab website

Image: Mikhail Fedurin, Timur Shaftan, Victor Smalyuk, Xi Yang, Junjie Li, Lewis Doom, Lihua Yu, and Yimei Zhu are the Brookhaven team of scientists that realized and demonstrated the new lens system for as ultra-fast electron diffraction imaging.

New beamline for electron bunch diagnostics

A new diagnostic beamline connected directly to the MAX IV linear accelerator is under construction.

It will enable time-resolved characterization of primarily the ultrashort electron bunches for the FemtoMAX beamline but will also be useful for other time-resolved experiments. The design of the highly specialized beamline components is to a large part done in-house.
Head up and tail down
The linear accelerator accelerates electrons up to high energies. Short bunches containing 109 electrons are delivered from the linear accelerator to make X-ray pulses for the FemtoMAX beamline. The duration of the bunches is in the femtosecond (10-15 s) regime to enable high temporal-resolution measurements at the beamline. The short duration makes the bunches very challenging to characterize with time resolution as conventional detection devices are too slow.
In the new setup, two so-called transverse deflecting cavities (TDC) will make the acquisition of time-resolved data possible. They will in principle add an electromagnetic field that deflects the head of the electron bunch upwards and the tail down so that the first electrons hitting the beam profile analyzer will end up at the top of the screen and the last ones will end up at the bottom. The resulting streak gives a time-resolved measurement of the shape of the bunch but the method will also be used to characterize for example how emittance and energy vary as a function of time.
– Today we rely on calculations and relative measurements for the bunch length delivered to FemtoMAX says project leader Erik Mansten, the TDC is a way for us to verify what we deliver. It also helps us preparing the linac for a possible free electron laser in the future.

>Read more on the MAX IV website

Image: These copper disks are going to become transverse deflecting cavities for the new diagnostic beamline.

Researchers create the first maps of two melatonin receptors essential for sleep

A better understanding of how these receptors work could enable scientists to design better therapeutics for sleep disorders, cancer and Type 2 diabetes.

An international team of researchers used an X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory to create the first detailed maps of two melatonin receptors that tell our bodies when to go to sleep or wake up, and guide other biological processes. A better understanding of how they work could enable researchers to design better drugs to combat sleep disorders, cancer and Type 2 diabetes. Their findings were published in two papers today in Nature.

The team, led by the University of Southern California, used X-rays from SLAC’s Linac Coherent Light Source (LCLS) to map the receptors, MT1 and MT2, bound to four different compounds that activate them: an insomnia drug, a drug that mixes melatonin with the antidepressant serotonin, and two melatonin analogs.

>Read more on the LCLS at SLAC website

Image: The researchers showed that both melatonin receptors contain narrow channels embedded in the cell’s fatty membranes. These channels only allow melatonin, which can exist happily in both water and fat, to pass through, preventing serotonin, which has a similar structure but is only happy in watery environments, from binding to the receptor. They also uncovered how some much larger compounds only target MT1 despite the structural similarities between the two receptors.
Credit: Greg Stewart/SLAC National Accelerator Laboratory


Superconductor exhibits “glassy” electronic phase

The study provides valuable insight into the nature of collective electron behaviors and how they relate to high-temperature superconductivity.

At extremely low temperatures, superconductors conduct electricity without resistance, a characteristic that’s already being used in cryogenically cooled power lines and quantum-computer prototypes. To apply this characteristic more widely, however, it’s necessary to raise the temperature at which materials become superconducting. Unfortunately, the exact mechanism by which this happens remains unclear.

Recently, scientists found that electrons in cuprate superconductors can self-organize into charge-density waves—periodic modulations in electron density that hinder the flow of electrons. As this effect is antagonistic to superconductivity, tremendous effort has been devoted to fully characterizing this charge-order phase and its interplay with high-temperature superconductivity.

>Read more on the Advanced Light Source at L. Berkeley Lab website

Image: At low doping levels, the charge correlations in the copper–oxide plane possess full rotational symmetry (Cinf) in reciprocal space (left), in marked contrast to all previous reports of bond-oriented charge order in cuprates. In real space (right), this corresponds to a “glassy” state with an apparent tendency to periodic ordering, but without any preference in orientation (scale bar ~5 unit cells).

Catalyst renders nerve agents harmless

Scientists used a multimodal approach to understand how a catalyst decomposes nerve agents in real-life environments

A team of scientists including researchers at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory has studied a catalyst that decomposes nerve agents, eliminating their harmful and lethal effects. The research was published Friday, April 19, in the Journal of Physical Chemistry Letters.

“Our work is part of an ongoing, multiagency effort to protect soldiers and civilians from chemical warfare agents (CWAs),” said Anatoly Frenkel, a physicist with a joint appointment at Brookhaven Lab and Stony Brook University and the lead author on the paper. “The research requires us to understand molecular interactions on a very small scale, and to develop special characterization methods that are capable of observing those interactions. It is a very complex set of problems that also has a very immediate societal impact.”

>Read more on the National Synchrotron Light Source-II website

Image: Lead author Anatoly Frenkel is shown at NSLS-II’s X-ray Powder Diffraction beamline, where part of the research was conducted.