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2018 ALS User Meeting Highlights

2018/10/192018/10/25

Past, present, and future converged at the ALS User Meeting, held October 2–4, 2018. About 480 registrants helped celebrate the 25th anniversary of first light at the ALS and the announcement of CD-1 approval for the ALS Upgrade project (ALS-U), a major federal milestone. Users’ Executive Committee (UEC) Chair Will Chueh kicked things off by acknowledging the organizers—UEC members Jennifer Ciezak-Jenkins, Alex Frañó, and Michael Jacobs—and thanking the ALS for its support. He also explained the organizing principle behind the program: to engage student and young-scientist users and strengthen interactions between users in general. Jeff Neaton, Berkeley Lab’s Associate Laboratory Director for Energy Sciences, then extended an official welcome to attendees. He noted that it’s been an exciting year for the ALS, which gained a new director, Steve Kevan, in addition to CD-1 approval for ALS-U.

Image: Plenary session, Day 1.
Credit: Peter DaSilva/Berkeley Lab

The search for clean hydrogen fuel

2018/10/192018/10/22

The world is transitioning away from fossil fuels and hydrogen is poised to be the replacement.

Two things are needed if we are to make the transition to a low carbon, “hydrogen economy” they are clean and high yielding sources of hydrogen, as well as efficient means of producing and storing energy using hydrogen.

Hydrogen powered cars are the perfect case study for how a hydrogen-fuelled future would look. While they work and show a great deal of promise, the best examples of hydrogen being used in fuel require very clean sources of hydrogen. If the source of hydrogen is mixed with contaminants like carbon monoxide, the efficiency of the fuel goes down and causes downstream problems in the fuel cell.

A team from KTH led by Jonas Weissenrieder is visiting MAX IV this week to try and solve this exact problem, how can we generate clean hydrogen for fuel cells? The team is working on a process to catalyse the oxidation of carbon monoxide, which adversely affects fuel cell performance, to harmless carbon dioxide. The catalysis reaction must be selective, and not affect the hydrogen gas that could be oxidised to water which is not great for running car engines.

Acid-base equilibria: not exactly like you remember in chemistry class

2018/10/18

Work published in the Royal Society of Chemistry with the support of the Helmholtz Association through the Center for Free-Electron Laser Science at DESY, MAX IV Laboratory, Lund University, Sweden, European Research Council (ERC) under the European Union’s Horizon 2020 and the Academy of Finland.

Remember doing titrations in chemistry class? Adding acid drop-by-drop to the beaker and the moment you took your eye off it the solution completely changed colour.
We learned in chemistry that by doing this titration, we were actually affecting an important equilibrium in the beaker between acids and bases. This equilibrium was first described at the turn of the 20th century by American biochemist Lawrence Henderson and modified by Karl Hasselbalch giving us the Henderson-Hasselbalch equation. The discovery and subsequent study of acids and bases using this equation has led to the discovery of many important phenomena in the natural world from as how cells function to how materials are formed.

However, after years of study, an idea arose that questioned the validity of the Henderson-Hasselbalch equation, what happens at the surface? If you have a beaker filled with a dilute acid, what happens at the very top atomic layer? The top layer of a liquid in a beaker is special for many reasons, but if you’re a dissolved molecule, it means that you’re no longer surrounded by water on all sides. For hydrophobic molecules, this means that it is favourable to be at the surface. With this in mind, the scientists took another look at the Henderson-Hasselbalch equilibrium equation and thought that it couldn’t work at the surface. Many studies have measured indicator chemical species, and determined that the Henderson-Hasselbalch equation does not seem to apply at the surface, and concluded that the concentration of hydronium or hydroxide ions, which determines the acidity/basicity, is different at the air-liquid interface than in the bulk.

Defense spending bill extends Air Force research partnership

2018/10/182018/10/30

For the past 10 years, the U.S. Air Force has funded research on high-performance materials at the Cornell High Energy Synchrotron Source (CHESS).

The partnership has resulted in numerous advances, including a greater understanding of metal fatigue and analysis of the best metals for aircraft.
This partnership was extended with $8 million in funding to CHESS as part of the fiscal year 2019 defense appropriations bill, a $674.4 billion package that President Donald Trump signed into law Oct. 1. The bill passed both the U.S. Senate – supported by New York Sens. Charles Schumer, who is Senate minority leader, and Kirsten Gillibrand – and the U.S. House of Representatives late last month.

“Cornell University is deeply grateful to Leader Schumer and Senator Gillibrand for securing $8 million in additional funding for CHESS,” Cornell President Martha E. Pollack said in a statement. “Maintaining our scientific infrastructure is essential if the U.S. is to keep its competitive advantage in research and development. Over the years, taxpayers have invested more than $1 billion in CHESS, an investment that’s paid off many times over in new discoveries, breakthrough technologies, [science, technology, engineering, math] education and workforce development.”

Image: Matthew Miller, right, associate director of the Cornell High Energy Synchrotron Source (CHESS), watches graduate student Mark Obstalecki prepare a sample for analysis in the F2 hutch at CHESS.

First in situ X-ray Absorption study of liquid battery cells

2018/10/182018/10/25

A greener future depends on better batteries: to move away from fossil fuels, we need rechargeable batteries with higher power and energy density to store intermittent energy from solar and wind. Moreover, these batteries could completely replace fossil fuels in vehicles.

Metal-air batteries seem like the answer, with the highest theoretical ability to pack energy into a small space (a property called energy density) of all current battery types.
“If we can achieve the theoretical energy density of metal air batteries and use them in vehicles, we can have much more driving range and make them more competitive with internal combustion engines that are currently used in cars,” says Mohammad Banis, a Western University researcher whose recent work looked at the charge and discharge cycles of a sodium-air battery in action.

Banis, who works in Andy Xueliang Sun’s clean energy research group at Western, spent a full year stationed at the Canadian Light Source to develop new tools for battery research. Observing the real time behaviour of material during charge cycles of a metal air battery presents a puzzle: the soft X-ray technique used typically requires a vacuum chamber, which makes it particularly difficult to study a liquid system.

Image: Mohammad Banis at a Canadian Light Source beamline where he studies batteries.

Insights into an antibody directed against dengue virus

2018/10/162018/10/19

We are one step further to uncovering a new way to stave off dengue fever thanks to important work carried out at the I02 beamline at Diamond Light Source.

The study, recently published in Nature Immunology, describes how an antibody effectively targets the dengue virus.
Dengue virus affects hundreds of millions of people worldwide and is an untreatable infection. Secondary infections with dengue can lead to a life-threatening form of the disease due to a phenomenon called antibody-dependent enhancement (ADE). Additionally, efforts to develop a vaccine against the virus have been hindered by ADE.

A huge collaborative effort sought to investigate ADE in dengue, and two antibodies were characterised that bound to the envelope protein of the dengue virus. One of the antibodies was found to be a potent neutraliser of the virus, but importantly was unable to promote ADE.

Image: Fab binding in the context of the mature virion. e, Comparison of 2C8 Fab and 3H5 Fab docked onto a E dimer. 2C8 (green) and 3H5 (orange) Fabs were docked onto PDB ID 3J27 by aligning the EDIII potion of the structures. The Fabs are shown as surfaces and the E dimer is displayed in cartoon representation. A side view is of the E dimer on the viral surface is shown. The approximate location of the viral membrane is shown schematically.

Blue phosphorus – mapped and measured for the first time

2018/10/152018/10/19

For the first time an HZB team was able to examine samples of blue phosphorus at BESSY II and confirm via mapping of their electronic band structure that this is actually this exotic phosphorus modification.

Blue phosphorus is an interesting candidate for new optoelectronic devices. The results have been published in Nano Letters.
The element phosphorus can exist in various allotropes and changes its properties with each new form. So far, red, violet, white and black phosphorus have been known. While some phosphorus compounds are essential for life, white phosphorus is poisonous and inflammable and black phosphorus – on the contrary – particularly robust. Now, another allotrope has been identified: In 2014, a team from Michigan State University, USA, performed model calculations to predict that “blue phosphorus” should be also stable. In this form, the phosphorus atoms arrange in a honeycomb structure similar to graphene, however, not completely flat but regularly “buckled”. Model calculations showed that blue phosphorus is not a narrow gap semiconductor like black phosphorus in the bulk but possesses the properties of a semiconductor with a rather large band gap of 2 electron volts. This large gap, which is seven times larger than in bulk black phosphorus, is important for optoelectronic applications.

Image: https://pubs.acs.org/doi/10.1021/acs.nanolett.8b01305

Lattice Coupling conspires in the correlated cuprate high-Tc superconductivity

2018/10/152018/10/25

For the cuprate high temperature superconductivity (high-T_c) research over the past three decades, the biggest challenge is to identify the relevant low energy degrees of freedom that are critical to formulating the correct theoretical model for high-T_c superconductivity. The main difficulty lies in the closeness between various relevant energy scales. For low energy processes that are comparable to the superconducting gap energy ∆_sc, there are the spin exchange energy J, the lattice vibration (phonon) energy Ω_ph, and the van Hove singularity energy E_(π,0). However, anomalous isotope effects on T_c and superfluid density in the cuprates cannot be captured by traditional phonon-mediated superconductivity theories. Historically, a purely electronic Hamiltonian – the Hubbard model – was widely regarded to encapsulate all the core physics of the high-T_c phenomena.

In a recent paper published in Science, scientists from Stanford University and from Stanford Institute for Materials and Energy Sciences (SIMES), in collaboration with material scientists from Japan and theoreticians from Japan, the Netherlands, and Berkeley, reinstated the substantial role of the lattice vibration in the cuprate high-T_c superconductivity – however, in a subtle way that is highly intertwined with the electronic correlations. They finely straddled 18 differently hole-doped high-T_c compound Bi₂Sr₂CaCu₂O_8+δ within 8% change of hole carrier concentration, a doping range where T_c evolves from 47 K to 95 K through a putative quantum critical point, around which the electronic correlation effect experiences a sudden change. Then systematic experiments were carried out using the angle-resolved photoemission spectroscopy (ARPES) facility at SSRL Beam Line 5-4. Here, the high-resolution ARPES end station provided critical information of both the superconducting gap and the electron-lattice coupling.

Image: Intertwined growth of the superconductivity and the electron-phonon coupling tuned by the hole concentration. The red line is an illustration of the T_c in Bi-2212 (T_c^max = 95 K). The blue shade and line represent the single-layer Bi-2201 system, where the coupling to the B1g mode is weak and T max is only 38 K. The yellow ball represents the optimally doped tri-layer Bi-2223 where T_c^max is 108 K. The top-right inset shows the intertwined relation between the pseudogap and the EPC under strong electronic correlation. The Madelung potential and the lattice stacking along the c-axis are schematically depicted for the single- layer, bi-layer and tri-layer systems. The dark grey blocks represent the CuO₂^n- plane, and the light grey blocks represent the charge reservoir layers (Ca²⁺, SrO, BiO⁺). The orange dots mark the CuO₂^n- planes that experience to the first order a non-zero out-of-plane electric field.
Credit: Science, doi: 10.1126/science.aar3394

Finding unusual performance in unconventional battery materials

2018/10/152018/10/18

Even as our electronic devices become ever more sophisticated and versatile, battery technology remains a stubborn bottleneck, preventing the full realization of promising applications such as electric vehicles and power-grid solar energy storage. Among the limitations of current materials are poor ionic and electron transport qualities. While strategies exist to improve these properties, and hence reduce charging times and enhance storage capacity, they are often expensive, difficult to implement on a large scale, and of only limited effectiveness. An alternative solution is the search for new materials with the desired atomic structures and characteristics. This is the strategy of a group of researchers who, utilizing ultra-bright x-rays from the U.S. Department of Energy’s Advanced Photon Source (APS), identified and characterized two niobium tungsten oxide materials that demonstrate much faster charging rates and power output than conventional lithium electrodes. Their work appeared in the journal Nature.

Currently, the usual approach for wringing extra capacity and performance from lithium-ion batteries involves the creation of electrode materials with nanoscale structures, which reduces the diffusion distances for lithium ions. However, this also tends to increase the practical volume of the material and can introduce unwanted additional chemical reactions. Further, when graphite electrodes are pushed to achieve high charging rates, irregular dendrites of lithium can form and grow, leading to short circuits, overheating, and even fires. Measures to prevent these dendrites generally cause a decrease in energy density. These issues seriously limit the use of graphite electrodes for high-rate applications.

Image: Artist’s impression of rapidly flowing lithium through the niobium tungsten oxide structure. This is a detail of the image, please see here for the entire art work.
Credit: Ella Maru Studio

Steering the outcome of photoionization in a molecule

2018/10/152018/10/25

An important step towards the understanding and control of photoinduced fragmentation processes in molecules has been achieved in an experiment on the H₂ molecule taking advantage of the unique properties of the FERMI free-electron laser source in the vacuum ultraviolet (VUV) photon energy range.
Molecular dissociation, i.e., the breaking of a chemical bond, is governed by the coupling of electronic and nuclear motion and, once understood and controlled in large systems, e.g., by utilizing ultrashort light pulses, has the potential to impact tremendously photochemical and biochemical applications. A team of both experimentalists and theoreticians from France (CNRS, Université Paris-Sud, Université de Bordeaux), Spain (Universidad Autónoma de Madrid), Germany (European XFEL), and Italy (Elettra-Sincrotrone Trieste) has demonstrated that the outcome of dissociative (DI) and nondissociative (NDI) photoionization in the simplest of all molecules, H₂, can be controlled exploiting nonlinear two-photon ionization with intense femtosecond pulses in the VUV.
The FERMI seeded free-electron laser is currently the only light source worldwide that provides external users access to bright femtosecond pulses at wavelengths in the VUV up to 100 nm, the energy regime required for studying nonlinear two-photon single-ionization in H₂. The high spectral resolution and precise tunability of the 100-fs pulses provided by FERMI made it possible to selectively excite single vibrational levels in the neutral intermediate B state of H₂ (blue line in Fig. 1). Absorption of a second VUV photon then leads to NDI or DI into the ionic H₂⁺ ground state (green in Fig. 1) or to DI into the first excited H₂⁺2p continuum (orange in Fig. 1). In single-photon single-ionization of H₂, the yield of DI is very low – less than 2%. By contrast, recent ab initiocalculations suggest that the ratio of DI/NDI can be increased significantly in resonance-enhanced two-photon ionization and that it can be controlled by varying the pulse duration between 2 and 10 fs.

>Read more on the Elettra website

Image: (a) Schematic of resonant two-photon ionization viathe B intermediate state (12.51 eV). The grey shaded area shows the Franck-Condon region for one-photon absorption from the H2electronic ground state. The dashed purple arrows visualize the range for the absorption of the second FEL photon. The green (red) horizontal line shows the ionization threshold at 15.43 eV (dissociation limit at 18.08 eV). (b) The experimental photoelectron spectrum shows a clear separation of electrons correlated to NDI and DI. For DI, it is close to the prediction of the Condon-reflection approximation, i.e., the projection of the vibrational wavefunction onto the dissociative 2p continuum state. The infinite-time limit calculation (grey line for the convolution of the contributions from the two first ionization continua) reproduces the main features of the spectrum. The differences between experiment and calculation indicates that at FERMI a timescale between ultrafast dynamics and steady-state excitation is probed.

The coolest high-energy synchrotron experiment

2018/10/122018/10/23

A French team of researchers has created and tested a cryostat where scientists can carry out the coldest experiments in the high-energy range in a synchrotron.

A photocopy of a drawing lies on the table of the control cabin of beamline ID12. It shows a cryostat and its heart: a spring-like metal tube and other components. Next to the drawing, lots of scribbles in different colours and on different dates, proof that this creation has been many years in the making. Steps away from the table, the real thing makes its appearance in the experimental hutch. Its majestic presence gives the beamline a new touch. It is the Très Basses Temperatures for miliKelvin (TBT-mK) cryostat.
Philippe Sainctavit, from the Institut de minéralogie, de physique des matériaux et de cosmochimie, together with Jean-Paul Kappler and Loïc Joly, from the Institut de Physique et Chimie des Matériaux de Strasbourg and synchrotron SOLEIL, are the fathers of this invention. “We started working on this project 20 years ago, and this is the third version of the machine”, explains Kappler. The team has installed the machine on ID12 for their experiments in magnetism. “Because this is quite a particular piece of equipment, we needed a very strong understanding with the beamline staff. Thanks to the fact that we were all in the same wavelength, the installation, which lasted 5 weeks spread throughout the year, went very smoothly. We could not have done this without the strong collaboration with the ID12 staff, namely Andrei Rogalev, Fabrice Wilhelm and Pascal Voisin”, explains Sainctavit.

A guide to central nervous system tomography

2018/10/122018/10/19

In-depth investigations on I13 to optimise soft tissue synchrotron X-ray microtomography

The Bradbury Lab at King’s College London, headed by Professor Elizabeth Bradbury, investigates damage to the central nervous system (CNS), and how the body responds to it. The traditional way of investigating soft tissue samples such as those of the central nervous system is 2D histology, in which slices are taken, stained and imaged. However, this process has limitations – slice thickness has a lower limit and measurements within cut slices are subject to inaccuracies arising from mechanical processing distortions. The group sent PhD student (now Dr) Merrick Strotton to the Diamond-Manchester Imaging Branchline I13-2 to investigate whether X-ray microtomography (a nominally non-destructive technique for taking a series of 2D images and turning them into a 3D volume) could avoid these issues. It wasn’t clear how to achieve the best possible results, and so alongside the biomedical studies, Dr Strotton worked with Diamond’s Dr Andrew Bodey on a series of methodological investigations on how to optimise imaging for soft tissue samples, the first results of which have recently been published in Scientific Reports.

Image: Segmentation of the low thoracic-high lumbar (T13-L1) level spinal cord sample from background, white & grey matter from spinal cord and vasculature from spinal cord with SuRVoS.
Credit: https://www.nature.com/articles/s41598-018-30520-8#Sec10

Samtack uses ALBA Synchrotron light for improving food packaging

2018/10/112018/10/19

Thanks to the CALIPSOplus European project, Samtack company is analysing at ALBA nanoparticles contained in a new food packaging system that will prevent food oxidation and extend its lifetime.

We all expect to purchase high quality and fresh food that, even if it has been kept for few days in the supermarket shelf, it still maintains its optimum safety and quality such as well as flavor. Different ambient conditions can modify food quality: moisture can affect the crispness of the product, oxygen can oxidize food with large fat components (e.g. potato chips) and change its taste, while light can degrade vitamins from milk or even remove the aromatic and volatile components from ground coffee and off-taste. Hence, different barriers are required to protect food from moisture, oxygen or light and that’s the point where packaging plays a key role. Packaging acts as a barrier and extends the product’s shelf life while contributing to diminish the amount of food that is thrown away and avoiding overproduction of food.

Samtack, founded in 1988 and based in Esparreguera (Barcelona), is a manufacturer of glues and adhesives specialized in the sector of graphic arts and packaging. Samtack has developed a new flexible multilayer system, in collaboration with the University of Zaragoza and the Complutense University of Madrid, that contains Selenium nanoparticles and is capable to increase food shelf life.

>Read more on the ALBA website

SwissFEL makes protein structures visible

2018/10/102018/10/18

Successful pilot experiment on biomolecules at the newest large research facility of PSI

For the development of new medicinal agents, accurate knowledge of biological processes in the body is a prerequisite. Here proteins play a crucial role. At the Paul Scherrer Institute PSI, the X-ray free-electron laser SwissFEL has now, for the first time, directed its strong light onto protein crystals and made their structures visible. The special characteristics of the X-ray laser enable completely novel experiments in which scientists can watch how proteins move and change their shape. The new method, which in Switzerland is only possible at PSI, will in the future aid in the discovery of new drugs.

Less than two years after the X-ray free-electron laser SwissFEL started operations, PSI researchers, together with the Swiss company leadXpro, have successfully completed their first experiment using it to study biological molecules. With that, they have achieved another milestone before this new PSI large research facility becomes available for experiments, at the beginning of 2019, to all users from academia and industry. SwissFEL is one of only five facilities worldwide in which researchers can investigate biological processes in proteins or protein complexes with high-energy X-ray laser light.

>Read more on the SwissFEL website

Image: Michael Hennig (left) and Karol Nass at the experiment station in SwissFEL where their pilot experiment was conducted.
Credit: Paul Scherrer Institute/Mahir Dzambegovic

Light at the end of the last tunnel

2018/10/102018/10/26

X-rays reach instruments HED and MID

During the afternoon and evening hours of Friday 5 October, the DESY accelerator team and the European XFEL photon commissioning team worked together to guide the first X-ray light through the last of the facility’s initial three X-ray beamlines, SASE2, and towards the last of the currently planned European XFEL instruments, the High Energy Density (HED) and Materials Imaging and Dynamics (MID) instruments.

At about midday on Friday, the X-ray light entered the photon tunnel leading to the SASE 2 instruments. To get there, the beam had to pass through a 12 mm horizontal aperture of the shutter collimator about 264 m from the source. In order to make this possible, alignment and vacuum system experts from the DESY accelerator group worked together during the last few months to precisely align the undulator section that generates X-ray laser light from accelerated electrons. This work was based on data obtained during the initial commissioning done in May 2018.

>Read more on the European XFEL website

Image: Screenshot of the first light.

Research on ancient teeth reveals complexity of human evolution

2018/10/092018/10/10

Fossil records enable a detailed reconstruction of our planet’s history and of the evolution of our species. In particular, teeth are a sort of biological archive that record in their structures (enamel, dentine and pulp chamber) the different phases of the human evolution. An international team of researchers led by Clément Zanolli from the Université Toulouse III Paul Sabatier (France) has characterized human dental remains from Fontana Ranuccio (Latium) and Visogliano (Friuli-Venezia Giulia), Italy through a comparative high-resolution endostructural analysis based on microfocus X-ray microtomography (mCT) scanning and detailed morphological analyses. We examined the shape and arrangement of tooth tissues (see Fig. 1) and compared them with teeth of other human species (see Fig. 2).

With an age of around 450,000 years before present, the analysed dental remains from the sites of Fontana Ranuccio, located 50 km south-east of Rome, and Visogliano, located 18 km north-west of Trieste, are part of a very short list of fossil human remains from Middle Pleistocene Europe and are among the oldest human remains on the Italian Peninsula.
From the data obtained through X-ray μ-CT measurements performed at the TomoLab station of Elettra and at the Multidisciplinary Laboratory of the ‘Abdus Salam’ International Centre for Theoretical Physics in Trieste (Italy), we found that the teeth of both sites share similarities with Neanderthals but they are distinct from modern humans. This study adds to an emerging picture of complex human evolution in Middle Pleistocene Eurasia. The investigated fossil teeth show that Neanderthal dental features had evolved by around 450,000 years ago.

Image: Volume rendering of the Fontana Ranuccio (FR1R and FR2) and Visogliano (Vis. 1-Vis. 6) tooth specimens. The enamel is represented in blue while the dentine in yellow. All specimens were imaged by X-ray μCT at the Tomolab station of Elettra and at the Multidisciplinary Laboratory of the ICTP.
Credit: doi: 10.1371/journal.pone.0189773