Tag: new device

Rich electronic features of a kagome superconductor

Rich electronic features of a kagome superconductor

The recently discovered layered kagome metals AV3Sb5 (A=K, Rb, Cs) exhibit diverse correlated phenomena, thought to be linked to so-called Van Hove singularities (VHSs) and flat bands in the material. Using a combination of polarization-dependent angle-resolved photoemission spectroscopy (ARPES) and density-functional theory, researchers led by Professor Ming Shi at the Paul Scherrer Institute directly revealed the sublattice properties of 3d-orbital VHSs and flat bands, as well as topologically non-trivial surface states in CsV3Sb5. The research reveals important insights into the material’s electronic structure and provides a basis for understanding correlation phenomena in the metals.

So-called kagome metals, named after the Japanese woven bamboo pattern their structure resembles, feature symmetrical patterns of interlaced, corner-sharing triangles. This unusual lattice geometry and its inherent features lead, in turn, to curious quantum phenomena such as unconventional, or high-temperature, superconductivity.

The potential for devices that might transport electricity without dissipation at room temperature—as well as a thirst for fundamental theoretical understanding—have led researchers to investigate this new class of quantum materials and try to figure out how electrons interact with the kagome lattice to generate such remarkable features.

A recently discovered class of AV3Sb5 kagome metals, where A can be =K, Rb or Cs, was shown, for instance, to feature bulk superconductivity in single crystals at a maximum Tc of 2.5 K at ambient pressure. Researchers suspect that this is a case of unconventional superconductivity, driven by some mechanism other than the phonon exchange that characterizes bonding in the electron-phonon coupled superconducting electron-pairs of conventional superconductivity.

This, as well as other exotic properties observed in the metal, are thought to be connected to its multiple “Van Hove singularities” (VHSs) near the Fermi level. VHSs, associated with the density of states (DOS), or set of different states that electrons may occupy at a particular energy level, can enhance correlation effects when a material is close to or reaches this energy level. If the Fermi level lies in the vicinity of a Van Hove point, the singular DOS determines the physical behavior due to the large number of available low-energy states. In particular, interaction effects get amplified not only in the particle-particle, but also in the particle-hole channels, leading to the notion of competing orders.

Read more on the PSI website

Image: Yong Hu, first author, and Nicholas Clark Plumb, who made the experimental station, at the Surface/Interface Spectroscopy (SIS) beamline of the Swiss Light Source (SLS) (L to R)

Credit: Paul Scherrer Institut / Mahir Dzambegovic

Expanding horizons with a new instrument

Expanding horizons with a new instrument

Work is in full swing to construct the new European XFEL instrument SXP. Manuel Izquierdo, who is the Group Leader for SXP since December 2020, gave insights into how the instrument will expand the European XFEL portfolio, when it is set to begin operations and what his vision is for the instrument at this stage.

How would you describe the SXP instrument?

SXP stands for “Soft X-ray Port”. This name was chosen in keeping with the core idea of the project, that is, to provide the users an FEL beamline where they can temporarily set up their own experiment stations. And, this is what makes the instrument unique: users can bring and operate their own experiment stations. This will allow many techniques and experiments to be implemented. The successful proposals would be those that cannot be performed at the two soft X-ray instruments SCS or SQS. So basically, the idea is that the SXP instrument will expand the portfolio of techniques available to users at European XFEL.

What kind of experiments will be performed at SXP? 

In principle it is up to the user community to suggest. So far, three communities have contributed to the project. One community aims to use European XFEL as a laboratory for astrophysics, atomic physics, and fundamental research investigating highly charged ions. A second community proposed studies on chemical bond activation in biological reactions and inorganic catalysts. The third and biggest community aims to perform time and angle-resolved photoelectron spectroscopy experiments in solids. This technique will allow understanding the atomic structure, chemical, electronic and magnetic properties of materials. The counter part for atoms, molecules and clusters can be done at the SQS instrument.

Read more on the European XFEL website

Image: Panorama view of the SASE3 beamline, which feeds SQS and SCS, and will now include SXP

Credit: Photograph by Dirk Nolle (Copyright: DESY)

SESAME: the doors are closed, but open for science

SESAME: the doors are closed, but open for science

Quarantine and curfew are affecting many activities in Jordan and abroad, but although SESAME’s doors have been closed since March 18th, the staff have been anything but inactive, devoting a great deal of their time at home to science and work.

With two new papers just published in the past few weeks, Messaoud Harfouche, the XAFS/XRF Beamline Scientist, keeps himself busy helping more users obtain results from the data taken at the beamline. “During these weeks, I am dealing with six projects at the same time, two from Egypt, two from Pakistan, one from Iran, and one from Jordan” he says. Given the difficulty of XAFS analysis and the complexity of some software packages, the degree of involvement in each project may vary from suggesting the best path in data analysis to full collaboration, implying result interpretation and participation in drafting a scientific paper. “Moreover”, continues Messaoud, “my own research projects were also in my drawer, waiting to be worked out. With willpower and a little perseverance, curfew may turn out to be very beneficial”.

On another front, scientists from synchrotron radiation laboratories in different points in Europe (ELETTRA in Italy, ESRF in France and SOLARIS in Poland) and SESAME in Jordan are collaborating at a distance on raytracing simulations for the Technical Design Report (TDR) of SESAME’s BEATS (BEAmline for Tomography at SESAME) beamline which is approaching finalization, and from their respective homes Matteo Altissimo (ELETTRA), Alexander Rack (ESRF), Tomasz Kolodziaj (SOLARIS), and Gianluca Iori (SESAME) are constantly in touch with each other. In parallel, from their homes, too, team members of SESAME’s technical sector have been collaborating in the final design of the front end and experimental station of the beamline. BEATS is SESAME’s hard X-ray tomography beamline that is expected to come on stream in 2022.

>Read more on the SESAME website

Picture: As in the case of thousands of researchers worldwide, computer screens and notebooks are currently the main tools for the work of SESAME’s staff.

Super laser delivered to European XFEL

Super laser delivered to European XFEL

High Energy laser will enable study of exoplanet interiors.

A keenly awaited piece of high-tech equipment has been delivered to European XFEL. The high repetition rate, high-energy laser, DiPOLE 100-X, was developed in the UK by scientists and engineers at the Science and Technology Facilities Council’s Central Laser Facility (CFL) as part of the UK contribution to the facility. This unique laser, developed within the framework of the HiBEF user consortium, will be used at the instrument for High-Energy Density (HED) science at European XFEL to generate extreme temperatures and pressures in materials. The atomic structure and dynamics of these extreme states of materials can then be studied using the extremely bright and intense X-ray pulses produced by the European XFEL. This experimental set-up will enable scientists to create conditions similar to the interior of exoplanets with temperatures of up to 10,000°C, and pressures of up to 10,000 tons per square centimeter – similar to the weight of 2000 adult elephants concentrated onto the surface of a postage stamp!

>Read more on the European XFEL website

Image: The HED instrument at European XFEL.
Credit: European XFEL/Jan Hosan

New detector accelerates protein crystallography

New detector accelerates protein crystallography

In Feburary a new detector was installed at one of the three MX beamlines at HZB.

Compared to the old detector the new one is better, faster and more sensitive. It allows to acquire complete data sets of complex proteins within a very short time.

Proteins consist of thousands of building blocks that can form complex architectures with folded or entangled regions. However, their shape plays a decisive role in the function of the protein in the organism. Using macromolecular crystallography at BESSY II, it is possible to decipher the architecture of protein molecules. For this purpose, tiny protein crystals are irradiated with X-ray light from the synchrotron source BESSY II. From the obtained diffraction patterns, the morphology of the molecules can be calculated.

>Read more on the BESSY II at HZB website

Image: 60s on the new detector were sufficient to obtain the electron density of the PETase enzyme.
Credit: HZB

Welcome back users!

Welcome back users!

This month marks the official start of user operation at CHESS and all three partner programs: The NSF funded CHEXS, as well as MacCHESS supported by NIH and NYSTAR, and the Materials Solutions Network at CHESS, or MSN-C, funded by the Air Force Research Lab (AFRL), all welcomed users to new hutches and beamlines. 

Louise Debefve stands outside a hutch on the experimental floor of the Cornell High Energy Synchrotron Source, CHESS. She is preparing the experimental equipment for some of the first data to be collected at CHESS since the completion of the CHESS-U upgrade. The platinum samples that she is about to study at the new beamlines will provide insights into the catalytic function of the element, enabling for example the generation of cleaner energy powering everything from cars to laptops.

But for now, Louise is happy to just be using the X-rays again, a familiar occurrence for the former graduate student, who spent years developing her research of catalysts through the use of X-rays at SSRL. As a postdoc at CHESS, Louise initially found herself right in the middle of the feverish construction of the upgrade, with no X-rays available for research.

>Read more on the CHESS website

Image: Louise Debefve, right, works with Chris Pollock and Ken Finkelstein at the new PIPOXS station.

Simulating earthquakes and meteorite impacts in the lab

Simulating earthquakes and meteorite impacts in the lab

New device squeezes samples with 1.6 billion atmospheres per second.

A new super-fast high-pressure device at DESY’s X-ray light source PETRA III allows scientists to simulate and study earthquakes and meteorite impacts more realistically in the lab. The new-generation dynamic diamond anvil cell (dDAC), developed by scientists from Lawrence Livermore National Laboratory (LLNL), DESY, the European Synchrotron Radiation Source ESRF, and the universities of Oxford, Bayreuth and Frankfurt/Main, compresses samples faster than any similar device before. The instrument can turn up the pressure at a record rate of 1.6 billion atmospheres per second (160 terapascals per second, TPa/s) and can be used for a wide range of dynamic high-pressure studies. The developers present their new device, that has already proven its capabilities in various materials experiments, in the journal Review of Scientific Instruments.
“For more than half a century the diamond anvil cell or DAC has been the primary tool to create static high pressures to study the physics and chemistry of materials under those extreme conditions, for example to explore the physical properties of materials at the center of the Earth at 3.5 million atmospheres,” said lead author Zsolt Jenei from LLNL. To simulate fast dynamic processes like earthquakes and asteroid impacts more realistically with high compression rates in the lab, Jenei’s team, in collaboration with DESY scientists, now developed a new generation of dynamically driven diamond anvil cell (dDAC), inspired by the pioneering original LLNL design, and coupled it with the new fast X-ray diffraction setup of the Extreme Conditions Beamline P02.2 at PETRA III.

>Read more on the PETRA III at DESY website

Image: Artist’s impression of a meteorite impact.
Credit: NASA

17 meter long detector chamber delivered to CoSAXS

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

New beamline for electron bunch diagnostics

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.

SESAME hosts BEATS kick-off meeting

SESAME hosts BEATS kick-off meeting

The kick-off meeting of the BEAmline for Tomography at SESAME (BEATS) project, was held in Allan, Jordan and hosted by SESAME on the 12th and 13th March 2019. BEATS is an EU funded project with the objective to design, procure, construct and commission a facility for hard X-ray full-field tomography at the SESAME synchrotron. The European grant is worth 6 million euros and will span a four-year period from beginning 2019 to end 2022 and is funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement n°822535.

>Read more on the SESAME website

ESRF installs first components of new Extremely Brilliant Source

ESRF installs first components of new Extremely Brilliant Source

The ESRF’s new Extremely Brilliant Source (EBS) is officially entering a new stage.

This week, the first components for the EBS – the world’s first, high-energy fourth-generation synchrotron light source – have been installed in its storage ring tunnel: a new milestone in the history of the European Synchrotron.
The first Extremely Brilliant Source girders have been installed in the ESRF’s storage ring tunnel. “It’s a great moment for all the teams,” said Pantaleo Raimondi, ESRF accelerator & source director. “Seeing the first girders installed on time is testament to the expertise, hard work and commitment of all involved for more than four years. EBS represents a great leap forward in progress and innovation for the new generation of synchrotrons.”

The start of installation is a key milestone in the facility’s 150M€ pioneering upgrade programme to replace its third-generation source with a revolutionary and award-winning machine that will boost the performance of its generated X-ray beams by 100, giving scientists new research opportunities in fields such as health, energy, the environment, industry and nanotechnologies. The EBS lattice has already been adopted by other synchrotrons around the world, and 18 upgrades following EBS’s example are planned, including in the United States, in Japan and in China.

>Read more on the European Synchrotron website

Image: The first 12-tonne EBS girder is lowered into the storage ring tunnel.

Project Director Dave Robin announces ALS-U project beamlines

Project Director Dave Robin announces ALS-U project beamlines

Over the past year, a process involving ALS and ALS-U staff, the ALS user community, and external advisory committees has been ongoing to select the insertion-device beamlines that will be built and upgraded within the scope of the ALS-U Project. These beamlines will join existing ALS beamlines to form the full complement of capabilities that will be available at the upgraded ALS in several years. I am delighted to inform you that the selection process is now complete and to announce the result.

The ALS-U Project will build two new beamlines

  • a soft x-ray beamline in Sector 10, dubbed “FLEXON,” whose high-brightness coherent flux and multiple complementary techniques will probe the roles of multiscale heterogeneity in quantum materials; and
  • a tender x-ray beamline in Sector 8, whose coherent scattering and scanning spectromicroscopy capabilities will address challenges at the frontiers of diverse scientific areas, ranging from soft condensed matter and biomaterials to energy science and Earth and environmental sciences.

>Read more on the Advanced Light Source website

Image: ALS-U Project Director Dave Robin.

Construction starts on new Cryo-EM center

Construction starts on new Cryo-EM center

Called the Laboratory of BioMolecular Structure, the new cryo-electron microscope center will offer world-leading imaging capabilities for life sciences research.

Today, the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory broke ground on the Laboratory of BioMolecular Structure (LBMS), a state-of-the-art research center for life science imaging. At the heart of the center will be two new NY-State-funded cryo-electron microscopes (cryo-EM) specialized for studying biomaterials, such as complex protein structures.

“Cryo-electron microscopy is a rapidly-advancing imaging technique that is posting impressive results on a weekly basis,” said LBMS Director Sean McSweeney. “The mission of LBMS is to advance the scientific understanding of key biological processes and fundamental molecular structures.”

“Throughout my career, I have worked hard to make our region of the State a high-tech hub, bringing together the talents and expertise of scientists and facilities across Long Island.  I am pleased to have played a part in the creation of the new cryo-EM center, which will add to the incredible facilities at Brookhaven National Lab and enable our scientific community to lead the way in world-class imaging research and discovery,” said NY State Senator Ken LaValle.

>Read more on the NSLS-II at BNL website

Image: New York State Senator Ken LaValle joined leaders of Empire State Development and Brookhaven Lab for the LBMS groundbreaking ceremony. Pictured from left to right are Jim Misewich (Associate Laboratory Director for Energy and Photon Sciences, Brookhaven Lab), Erik Johnson (NSLS-II Deputy for Construction), Sean McSweeney (LBMS Director and NSLS-II Structural Biology Program Manager), Robert Gordon (DOE-Brookhaven Site Office Manager), Ken LaValle, Cara Longworth (Regional Director, Empire State Development), Danah Alexander (Senior Project Manager, Empire State Development), and John Hill (NSLS-II Director).

PHELIX beamline – undulator installation and hutch construction

PHELIX beamline – undulator installation and hutch construction

The PHELIX beamline construction continues. In October 2018 the light source for the beamline – an undulator – was installed in the storage ring. In November construction of the an optical hutch ended.

The hutch will protect people from radiation hazards. In the near future it will house the first optical components of the beamline.
The next planned steps are the installation of the front-end, i.e. the part of the beamline situated in the storage ring tunnel after the source (January 2019), the installation of the beamline with optical components for X-rays (February-March 2019) and the installation of the end-station (May-June 2019).

The PHELIX beamline will use soft X-rays. Its end station will enable a wide range of spectroscopic and absorption studies characterized by different surface sensitivity. In addition to collecting standard high-resolution spectra, it will allow, for example, to map the band structure in three dimensions and to detect electron spin in three dimensions. Users will, therefore, be able to conduct research on new materials, thin films and multilayers systems, catalysts and biomaterials, surface of bulk compounds, spin polarized surface states, as well as chemical reactions taking place on the surface.

>Read more on the SOLARIS website

Image credit: Agata Chrześcijanek

SESAME host to delegation from Helmholtz Association of German research centres

SESAME host to delegation from Helmholtz Association of German research centres

On 25th October, SESAME was host to a delegation from the Helmholtz Association of German Research Centres consisting of 43 persons. It was headed by Professor Otmar Wiestler, President of the Association.
The visiting delegation was shown round SESAME’s experimental hall and was able to see at first hand two of the Phase I beamlines that are already in operation, namely the XAFS/XRF (X-ray absorption fine structure/X-ray fluorescence) spectroscopy and IR (infrared) spectromicroscopy beamlines, as well as a further two Phase I beamlines, the MS (materials science) and MX (Macromolecular crystallography) beamlines, that are under construction and are expected to come on stream in two-three years.

During the visit, Otmar Wiestler informed SESAME that five research centres of the Helmholtz Association will be taking part in construction of a soft X-ray beamline for SESAME under the leadership of DESY (Deutsches Elektronen-Synchrotron). This is another of SESAME’s Phase I beamlines. The five research centres – DESY, FZJ (Forschungszentrum Jülich), HZB (Helmholtz-Zentrum Berlin), HZDR (Helmholtz-Zentrum Dresden-Rossendorf), and KIT (Karlsruher Institut für Technologie) – will be constructing a complete undulator beamline with monochromator and refocussing optics and a small chamber to conduct absorption and fluorescence yield experiments. The capital value of this work would be of the order of €3.5 million.
Given that the European Union has very recently informed SESAME that it will be providing €6 million for construction of its tomography beamline, SESAME will have six of its seven Phase I beamlines in operation relatively soon.

>Read more on the Synchrotron light for Experimental Science and Applications in the Middle East (SESAME) website

Image: (from left to right) Rolf Heuer, President SESAME Council, Otmar Wiestler, President Helmholtz Association, Khaled Toukan, SESAME Director, Walid Zidan, SESAME Administrative Director, and Rene Röspel, Member of the Bundestag and Vice-Chairman of the Science Committee of the Bundestag.
Credit: DESY

World record: Fastest 3D tomographic images at BESSY II

World record: Fastest 3D tomographic images at BESSY II

An HZB team has developed an ingenious precision rotary table at the EDDI beamline at BESSY II and combined it with particularly fast optics.

This enabled them to document the formation of pores in grains of metal during foaming processes at 25 tomographic images per second – a world record.

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends on the highest precision: Any tumbling around the rotation axis or even minimal deviations in the rotation speed would prevent the reliable calculation of the 3D tomography. While commercially available solutions costing several hundred thousand euros allow up to 20 tomographic images per second, the Berlin physicists were able to develop a significantly cheaper solution that is even faster. ”My two doctoral students at the Technische Universität Berlin produced the specimen holders themselves on the lathe”, says Garcia-Moreno, who not only enjoys working out solutions to tricky technical problems, but possesses a lot of craftsman skill himself as well. Additional components were produced in the HZB workshop. In addition, Garcia-Moreno and his colleague Dr. Catalina Jimenez had already developed specialized optics for the fast CMOS camera during the preliminary stages of this work that allows even for simultaneous diffraction. This makes it possible to record approximately 2000 projections per second, from which a total of 25 three-dimensional tomographic images can be created.

>Read more on the BESSY II at Helmholtz-Zentrum Berlin (HZB) website

Image: Experimental setup is composed of a fast-rotation stage, an IR heating lamp (temperature up to 800 °C), a BN crucible transparent to X-rays, a 200-μm thick LuAG:Ce scintillator, a white-beam optical system, and a PCO Dimax CMOS camera. The incident (red) and transmitted (green) X-ray beams as well as the light path from the scintillator to the camera (blue) are shown.
Credit: HZB