Record time resolution

RESEARCH TEAM DEMONSTRATES BEST PUMP–PROBE TIME RESOLUTION REPORTED SO FAR AT X-RAY FREE-ELECTRON LASER FACILITIES

After being illuminated with light, the atoms in materials react within femtoseconds, i.e. quadrillionths of a second. To observe these reactions in real time, the experiment setup used to capture them must operate with femtosecond time resolution too, otherwise the resulting images will be “blurred”. In a proof-of-principle experiment at the European XFEL, a research team has demonstrated a record time resolution of around 15 femtoseconds—the best resolution reported so far in a pump–probe experiment at an X-ray free-electron laser (FEL) facility, while keeping a high spectral resolution. “These results open up the possibility of doing time-resolved experiments with unprecedented time resolution, enabling the observation of ultrafast processes in materials that were not accessible before,” explains Daniel Rivas from European XFEL, principal investigator of the experiment and first author of the publication in the scientific journal Optica, in which the team from European XFEL and the DESY research centre in Hamburg report their results.

One of the goals of experiments at the European XFEL is to record “molecular movies”, i.e. series of snapshots of dynamic processes taken in extremely rapid succession, which reveal the details of chemical reactions or physical changes in materials at high time resolution. Understanding the molecular rearrangement during such reactions is an essential step towards controlling processes in our natural environment, such as radiation damage in biological systems or photochemical and catalytic reactions. One technique to create such movies is pump–probe spectroscopy, where an optical laser pulse (the “pump” pulse) excites a certain process in a sample and the X-ray laser pulses (the “probe” pulses) are used to take a series of snapshots in order to observe how the process evolves in time.

Read more on the European XFEL website

Image: An ultrashort X-ray pulse and an optical laser pulse interact simultaneously with a neon atom. The X-ray pulse removes an electron from the inner electronic shell and, due to the electromagnetic field of the optical laser that is present at the moment of ionization, the outcoming electron is modulated in energy.

Credit: illustratoren.de/TobiasWuestefeld in cooperation with European XFEL

Everyone remembers their 1st day at a light source

Light sources around the world share a common quality. They all have the ability to deliver a ‘wow factor’ when people first step inside. From young, bright eyed, tech-savvy children; scientists embarking on their first experiments; right through to retired visitors who spent their younger years without telephones or TVs. Synchrotron and X-ray Free Electron Lasers (XFELs) deliver science and technology on a grand scale. In this #LightSourceSelfie, Ida, a Phd Student at the ESRF, and Michael, who undertakes experiments at the European XFEL, both recall their first day. The words they use include exciting, overwhelming, exhilarating, busy and fascinating. Michael remembers feeling slightly in the way but, at a certain point, he started to ask questions. From that first day he learnt to, “Always ask questions. You can’t ask enough questions!”

Brilliant people support light source experiments

Academic and industrial researchers have access to world class experimental techniques at light sources around the world. Experimental time on the beamlines is extremely precious and in order to get the most out of this ‘beamtime’ scientists need expert advice and support. Today’s #LightSourceSelfie Monday Montage is a tribute to the brilliant scientists, engineers, computer scientists and other support staff who work at light sources and provide external researchers with the assistance they need to ensure their experiments are successful and they come away with useful data that will advance their scientific studies.

Monday Montage – Brilliant people support light source experiments

World changing science with precious photons

he 3.4 km long European XFEL generates extremely intense X-ray flashes used by researchers from all over the world. The flashes are produced in underground tunnels and they enable scientists to conduct a wide range of experiments including mapping atomic details of viruses, filming chemical reactions, and studying processes in the interior of planets.

Michael Schneider is a physicist at the Max Born Institute in Berlin. He uses synchrotrons and free electron lasers, such as the European XFEL, to study magnetism and magnetic materials. Michael’s fascinating #LightSourceSelfie takes you inside the European XFEL where he recalls the fact that it was large scale facilities themselves that first attracted him to his area of fundamental research. The work is bringing us closer to a new generation of computing devices that work more like the neurons in our brains that the transistors that we currently have in our computers. Michael captures the dedication of his colleagues and the facility teams, along with the type of work that you can get involved with at large scale facilities. He also gives a brilliant overview of the stages involved in conducting research at a light source. Michael is clearly very passionate about his science, but also finds time for some great hobbies too!

An abundance of talents within the light source community

Monday Montage – Talents!

Our #LightSourceSelfies campaign has uncovered a wealth of talents among staff and users at light source facilities around the world. From skating to sculpting and painting to perennials, this Monday Montage illustrates the many hobbies and interests that those in our community enjoy in their spare time. With contributions from the ESRF, SESAME, LCLS and the European XFEL, this montage highlights the variety of activities that help people maintain a healthy work/life balance.

X-ray laser reveals how radiation damage arises

DOUBLE BOMBARDMENT EXPOSES THE DETAILED DYNAMICS OF HOW WATER MOLECULES BREAK APART

An international research team has used the SQS instrument at the European XFEL to gain new insights into how radiation damage occurs in biological tissue. The study reveals in detail how water molecules are broken apart by high-energy radiation, creating potentially hazardous electrically charged ions, which can go on to trigger harmful reactions in the organism. The team led by Maria Novella Piancastelli and Renaud Guillemin from the Sorbonne in Paris, Ludger Inhester from DESY and Till Jahnke from European XFEL presents its observations and analyses in the scientific journal Physical Review X.

Since water is present in every known organism, the so-called photolysis of water is often the starting point for radiation damage. “However, the chain of reactions that can be triggered in the body by high-energy radiation is still not fully understood,” explains Inhester. “For example, even just observing the formation of individual ions and radicals in water when high-energy radiation is absorbed is already very difficult.”

Read more on the XFEL website

Image: After the absorption of an X-ray photon, the water molecule can bend up so far that after only about ten femtoseconds (quadrillionths of a second) both hydrogen atoms (grey) are facing each other, with the oxygen atom (red) in the middle. This motion can be studied by absorbing a second X-ray photon.

Credit: DESY, Ludger Inhester

Uniting science to address climate change

Key leaders and researchers from major US and European big science laboratories, namely EIROforum (Europe’s eight largest intergovernmental scientific research organisations, including CERN, EMBL, ESA, ESO, ESRF, EUROfusion, European XFEL and ILL) and the US Department of Energy’s seventeen National Laboratories (Ames, Argonne, Brookhaven, Fermi, Idaho, Jefferson, Los Alamos, Lawrence Berkeley, Lawrence Livermore, NETL, NREL, Oak Ridge, Pacific Northwest, PPPL, SLAC, Sandia and Savannah River), met by videoconference ahead of the United Nations Framework Convention on Climate Change Conference of Parties (COP26).

Sharing the same values, and convinced that science performs best through collaboration, the EIROforum’s directors and NLDC (comprised of directors from the US National Laboratories) affirmed their common commitment to unite science towards a sustainable and resilient global society and economy:

  • By stepping up their scientific collaboration on carbon-neutral energy and climate change
  • By sharing best practices to improve the climate sustainability and carbon footprint of Europe’s and US’s big science facilities
  • By sharing knowledge and fostering public engagement on clean energy and climate change research

Read more on the ESRF website

Image: COP26

Credit: ESRF

An X-ray view of carbon

New measurement method promises spectacular insights into the interior of planets

At the heart of planets, extreme states are to be found: temperatures of thousands of degrees, pressures a million times greater than atmospheric pressure. They can therefore only be explored directly to a limited extent – which is why the expert community is trying to use sophisticated experiments to recreate equivalent extreme conditions. An international research team including the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has adapted an established measurement method to these extreme conditions and tested it successfully: Using the light flashes of the world’s strongest X-ray laser the team managed to take a closer look at the important element, carbon, along with its chemical properties. As reported in the journal Physics of Plasmas (DOI: 10.1063/5.0048150), the method now has the potential to deliver new insights into the interior of planets both within and outside of our solar system.

The heat is unimaginable, the pressure huge: The conditions in the interior of Jupiter or Saturn ensure that the matter found there exhibits an unusual state: It is as dense as a metal but, at the same time, electrically charged like a plasma. “We refer to this state as warm dense matter,” explains Dominik Kraus, physicist at HZDR and professor at the University of Rostock. “It is a transitional state between solid state and plasma that is found in the interior of planets, although it can occur briefly on Earth, too, for example during meteor impacts.” Examining this state of matter in any detail in the lab is a complicated process involving, for example, firing strong laser flashes at a sample, and, for the blink of an eye, heating and condensing it.

Read more on the HZDR website

Image: High-resolution spectroscopy will enable unique insights into chemistry happening deep inside planets

Credit: HZDR / U. Lehmann

Insights into coronavirus proteins using SAXS

A collaboration led by researchers from the European Molecular Biology Laboratory (EMBL) used small angle X-ray scattering (SAXS) at the European XFEL and obtained interesting data on samples containing coronavirus spike proteins including proteins of the isolated receptor biding domain. The results can, for example, help investigate how antibodies bind to the virus. This gives researchers a new tool that may improve understanding of our bodies’ immune response to coronavirus and help to develop medical strategies to overcome COVID-19

SAXS is a powerful technique as it allows researchers to gain insights into protein shape and function at the micro- and nanoscales. The technique has proven to be extremely useful in investigating macromolecular structures such as proteins, especially because it removes the need to crystallize these samples. This means researchers can study the sample in its native form under physiological conditions under which biological reactions occur.

Read more on the European XFEL website

Image: Seen here, the instrument SPB/SFX, where the SAXS experiment was carried out. Using this instrument researchers can study the three-dimensional structures of biological objects. Examples are biological molecules including crystals of macromolecules and macromolecular complexes as well as viruses, organelles, and cells.

Credit: European XFEL / Jan Hosan

Beaming in on Coronavirus details

User operation resumed at European XFEL end of March, and the first experiments to receive beamtime are those being carried out at the Single Particles, Clusters, and Biomolecules & Serial Femtosecond Crystallography (SPB/SFX) instrument. They will focus on getting deeper insights into the Coronavirus, and, if successful, can lead to a better understanding of the structure of key Coronavirus proteins. New information about the shapes of these proteins, which the virus needs to copy itself, will aid scientists in their quest to find ways to fight COVID.

“Three user collaborations have proposed experiments that will use two distinct approaches to study the Coronavirus. Two collaborations lead by scientists from DESY and Diamond Light Source will look at the structure and binding of ligands to the proteases of the Coronavirus,” says Adrian Mancuso, leading scientist at the SPB/SFX instrument. A ligand is a molecule that binds another specific molecule or atom. Some ligands deliver a signal during the binding process and can be thought of as signaling molecules, which interact with proteins in target cells called receptors. At the European XFEL, scientists can potentially observe the process of these ligands attaching to proteins at atomic resolution, however, first an ordered crystal of the relevant protein is required. “XFELs are uniquely positioned to watch how irreversible processes in proteins—such as binding of potential drug candidates—happen,” explains Mancuso.

Read more on the European XFEL website

Image: A shot from the control hutch showing one of the first COVID-related beamtimes at SPB/SFX

Credit: European XFEL

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)

A clear path to better insights into biomolecules

An international team of scientists, led by Kartik Ayyer from the Max Planck Institute for the Structure and Dynamics of Matter, Germany, has obtained some of the sharpest possible 3D images of gold nanoparticles, and the results lay the foundation for getting high resolution images of macromolecules. The study was carried out at European XFEL’s Single Particles, Clusters, and Biomolecules & Serial Femtosecond Crystallography (SPB/SFX) instrument and the results have been published in Optica.

Carbohydrates, lipids, proteins, and nucleic acids, all of which populate our cells and are vital for life, are macromolecules. A key to understanding how these macromolecules work lies in learning the details about their structure. The team used gold nanoparticles, which acted as a substitute for biomolecules, measured 10 million diffraction patterns and used them to generate 3D images with record-breaking resolution. Gold particles scatter much more X-rays than bio-samples and so make good test specimens. They are able to provide lot more data and this is good for fine-tuning methods that can then be used on biomolecules.

Read more on the European XFEL website

Image: Illustration of 3D diffraction pattern of octahedral nanoparticles obtained by combining many snapshots after structural selection.

Credit: Kartik Ayyer and Joerg Harms, Max Planck Institute for the Structure and Dynamics of Matter

Controlling tiny magnetic swirls

Research on skyrmions may lead to more effective data storage

Skyrmions, commonly imagined as tiny magnetic swirls, are nanoscale magnetic quasi-particles that have recently become a hot topic because of their potential in the development of faster and more effective data storage devices.

For the first time, an international group of scientists, with lead scientists from the Massachusetts Institute of Technology, US, and the Max-Born-Institut in Berlin  have successfully been able to observe the formation of skyrmions in a magnetic material by using ultrashort laser pulses in a magnetic material, shedding light into the microscopic process and its time period. The X-ray pulses of the European XFEL’s revealed the creation of tiny skyrmion structures on nanometer length scales at a speed which is faster than previously thought possible. The results have been published in Nature Materials.

At the atomic level, magnetic materials resemble a sea of magnetic spins in either an ‘up’ or ‘down’ orientation. These spins are linked to each other so that a single spin change will affect the orientation of other spins. Skyrmions are tiny swirl-like structures where the center spin is oppositely aligned to the spins located at its boundary with a twisted spin configuration in between. These complex spin structures are very stable and small, making them interesting candidates for future spintronic devices. Spintronics exploits both the spin and the charge of electrons that could lower energy consumption in future memory devices and data storages.

Read more on the European XFEL website

Image: A laser pulse transforms a uniform magnetization (magnetization down everywhere) to a skyrmion swirl where the magnetization in the center points up. This transformation changes the so-called topology of the system.

Credit: B. Pfau, Max Born Institute

Accurate temperature snapshots

The first high energy density experiments pave way for future research

What does it take to accurately measure the temperature of a material which remains in a stable condition for just a fleeting nanosecond (one millionth of a second)? Consider using the high energy density (HED) instrument at European XFEL. And this is what an international team of researchers, with lead researchers from SLAC National Accelerator Laboratory, US, Oxford University, UK, and European XFEL, have done. Establishing methods to accurately measure temperatures in rapidly-evolving, transient systems is important for diverse purposes such as developing materials for spacecraft thermal shields, which face extreme changes in temperature and pressure when re-entering the Earth’s atmosphere, or in the study of the interior of giant planets such as Jupiter, Saturn, Uranus and Neptune. 

Read more on the European XFEL website

Image: Ulf Zastrau, Group Leader HED at the Experiment Station. Copyright: Jan Scholzel

First megahertz rate timing jitter observed

A report published today in the Journal Optica demonstrates accurate synchronisation of optical and X-ray lasers crucial for pump-probe experiments at XFEL. These snapshots taken during a reaction are stitched together to make molecular movies.

One of the ultimate goals for scientists using state-of-the-art X-ray free-electron lasers such as European XFEL is to be able to film the details of chemical and biological reactions. By stitching together a series of snapshots taken at different time intervals during a reaction, a molecular movie can be made of the process. So called pump-probe experiments use a precisely synchronised optical laser to trigger a reaction (the ‘pump’), while the X-ray laser takes a snapshot of the molecular structure at defined times during the reaction (the ‘probe’).

European XFEL now generates the ultrafast and ultra-intense light pulses needed to capture these processes that occur on extremely short timescales. The pulses of X-ray light generated by European XFEL are each less than a few millionths of a billionth of a second, or a few femtoseconds – fast enough to capture the series of events in a biological or chemical reaction. An accurate synchronization of the X-ray and optical laser pulses at these timescales is, however, challenging. Furthermore, tiny variations in the alignment and path travelled by the laser pulses caused, for example, by fluctuations in air pressure, or expansion in the electrical cables, have a relatively large impact on the accuracy of this experimental set-up. This variation is known as ‘timing jitter’. For pump-probe experiments to be successful, the jitter must be kept to a minimum, and be accurately characterized so that scientists can take it into account when assessing their data.

Read more on the European XFEL website

Image : The XPB/SFX instrument at European XFEL.

Credit: European XFEL / Jan Hosan

Day of Light: 60th anniversary of the laser

The invention of the laser 60 years ago has transformed science and everyday life.

Sixty years after the first laser was operated on 16 May 1960 by Theodore Maiman at Hughes Research Laboratories in California, lasers have revolutionized everyday life as well as science. Lasers are also fundamental for research at the European XFEL. A public event on the European XFEL campus planned to celebrate this anniversary has been postponed to a later date.

When the world’s biggest X-ray laser and one of the planet’s brightest light sources, the European XFEL, started operation in 2017, it was the culmination of several decades of scientific progress in laser and X-ray laser technology. Lasers operating in the visible wavelength range were invented in the 1960s. In these lasers, radiation is generated from electron transitions in atoms or molecules. The light emitted is then continuously amplified between mirrors. This makes it comparatively easy to produce high-quality laser light, and many applications now shape our everyday lives. Examples range from impressive light installations, to high precision surgical instruments, broadband telecommunication, components in the electrical devices we carry in our pockets, and the laser pointer we use during presentations.

Read more on the XFEL website

Image: The optical laser system for pump-probe experiments in the laser lab.

Credit: European XFEL / Jan Hosan