#SynchroLightAt75 – Operation of the PAL-XFEL in 2020

After the PAL-XFEL was opened to the public in 2017, beamtime for user service has increased every year to provide more opportunities for user experiments. In 2020, 2,819 hours were provided for user beamtime out of the planned 2,910 hours and the beam availability was 96.9%. The provided beamtime of 2,819 hours was a significant increase from 2,409 hours in 2019, as shown in Table 1. To further increase beamtime, the PAL-XFEL has plans for 24-hour operation and simultaneous operation of hard and soft X-ray beamlines in the near future.

YearPlanned BeamtimeProvided BeamtimeAvailability
20182,012 h1,921 h95.5%
20192,503 h2,409 h96.2%
20202,910 h2,819 h96.9%
Table 1. Planned and provided beamtime in 2018, 2019, and 2020

FEL saturation of 0.062 nm (20 keV) was achieved for the first time in PAL-XFEL. The measured FEL energy using the e-loss scan was 408 uJ, the FEL radiation spectrum was 25.3 eV rms (0.127% of the center photon energy), and the FEL pulse duration (FWHM) was 11 fs, which corresponds to 1×1011 photons/pulse. The e-beam energy was 10.4 GeV and the undulator K was 1.4. The undulator gap scan was conducted for 20 undulators to check the FEL saturation as shown in Figure 1. Here, quadratic undulator tapering is applied for the last 6 undulators and the calculated gain length was 3.43 m.

Figure 1. Measurement results of the saturation curve at 20 keV photon energy

Two-color FEL generation with a single electron bunch has been successfully demonstrated for the hard X-ray undulator line, broadening the research capabilities at the PAL-XFEL. Test experiments have been conducted at two photon energies, 9.7 keV and 12.7 keV. A pump pulse is generated with 8 upstream undulators of the self-seeding section and a probe pulse is generated with 12 downstream undulators of the self-seeding section. The photon energies of the pulses can be independently controlled by changing the undulator parameter K and the time delay between two pulses can be controlled from 0 to 120 femtoseconds by using the magnetic chicane installed at the self-seeding section.

Figure 2. Intensity measurement results of two-color FEL generations.

Ultra-bright hard x-ray pulses using the self-seeded FEL were applied to the demonstration of serial femtosecond crystallography (SFX) experiments in 2020. We have consistently improved the spectral purity and peak of the self-seeded FEL using a laser heater and optimized crystal conditions over a hard x-ray range from 3.5 keV to 14.6 keV. The peak brightness for self-seeded hard x-ray pulses was enhanced to almost ten times greater than that of the SASE FEL over hard x-ray ranges. For example, the peak brightness of an x-ray at 9.7 keV is 3.2×1035 photons/(s·mm2·mrad2·0.1%BW), which is the highest peak brightness ever achieved for free-electron laser pulses. Thanks to the ultra-bright x-ray pulse with narrow bandwidth and superior spectral purity, SFX experiment results using the seeded FEL showed better data quality with high resolutions compared with that using the SASE FEL. This work has been published in Nature Photonics (https://doi.org/10.1038/s41566-021-00777-z).

Figure 3. Comparison of measured FEL intensity between SASE and self-seeding FEL.

Karen Appel’s #My1stLight

Karen was a beamline scientist at DESY and is currently a beamline scientist at the European XFEL

My first synchrotron experiment was at beamline L at DORIS at DESY, which at that time just set up the possibility to do micro-focus X-ray fluorescence measurements. The first experiment I was involved in was headed by the group of Prof Schenk at the Institute of Mineralogy of the University of Kiel  and focused on minerals that were formed at high pressures and high temperatures. At that moment, I was a PhD student at the University of Bonn, working on metamorphic rocks and isotope geochemistry of rocks and got involved in the experiment, because I was interested in analytical methods that could be applied to minerals that were formed at high pressures and temperatures. Besides some connections through my earlier studies, my main interest was to learn about this new method of X-ray fluoresence. We investigated the chemical trace element composition (Rare Earth elements) of minerals that were formed during metamorphic processes and commonly show a gradient of the element distribution, which is related to the metamorphic formation process. 

As we were simply providing the samples, we had the chance to have a close look at the instrumentation. Having worked with commercial machines so far, I remember that I was very much impressed by the modular set- up of a beamline and this one-day experience motivated me to apply for a job that was offered from GFZ Potsdam that included a main part in experimental work at beamline L.

Later, as a postdoc, my experiences led me into the van Gogh experiment, where we used the polychromatic mode at beamline L and were able to detect the elemental distributions of a van Gogh painting. Now I am working at the High Energy Density Science instrument at the European XFEL, studying extreme states of matter, allowing me to work as a beamline scientist and also pursue my own scientific interests.

Image (above): Karen and her colleague working at the experimental station at the beamline L of DORIS III.

Credit: DESY

Image: DE: Die Experimentierstation HED (High Energy Density Science) dient der Erforschung von Materie unter extremen Druck- und Temperaturbedingungen oder sehr starken elektromagnetischen Feldern. Zu den wissenschaftlichen Anwendungen gehört die Untersuchung von Zuständen, wie sie im Inneren astrophysikalischer Objekte wie Exoplaneten bestehen, von Phasenzuständen unter extremem Druck, von Plasmen mit hoher Dichte oder von Phasenübergängen komplexer Feststoffe unter dem Einfluss starker Magnetfelder. EN: The HED experiment station will be used to study matter under extreme conditions of pressure, temperature, or electromagnetic fields. Scientific applications will be studies of matter occurring inside astrophysical objects such as exoplanets, of new extreme-pressure phases and solid-density plasmas, and of phase transitions of complex solids in high magnetic fields.

Credit: European XFEL / Jan Hosan

Lightsources.org virtual symposium recording

Lightsources.org was delighted to welcome over 500 attendees to our live virtual symposium to mark the 75th Anniversary of the first direct observation of synchrotron light in a laboratory. The event, which was chaired by Sandra Ribeiro, Chair of lightsources.org and Communications Advisor for the Canadian Light Source, was held on the 28th April 2022 and you can watch the recording via the YouTube link below.

We received some lovely feedback after the live event, including this comment from Jeffrey T Collins at the Advanced Photon Source, Argonne National Laboratory in Illinois.

 “I have worked at the Advanced Photon Source for over 32 years and I learned many things during this event that I never knew before.  It was quite informative.  I look forward to re-watching the entire event.”

Jeffrey T Collins, Mechanical Engineering & Design Group Leader at Argonne National Laboratory

The symposium began with a historical introduction from Roland Pease, freelance science broadcaster who has been an enthusiastic support of light sources for many years.

Roland’s talk was followed by experts from the field giving talks on their perspectives of synchrotron light related achievements that have been made since the 1st laboratory observation on the 24th April 1947.

Speakers were:

• Nobel Laureate Prof. Ada Yonath (Weizmann Institute of Science)

• Prof. Sir Richard Catlow (University College London)

• Prof. Henry Chapman (DESY)

• Dr Paul Tafforeau (ESRF)

• Dr Gihan Kamel (SESAME and member of the AfLS Executive Committee).

There followed a panel discussion with special guests who all made huge contributions to the development of the field. Our special guests were:

Herman Winick – Prof. of Applied Physics (Research) Emeritus at SLAC)

Ian Munro – Initiator of synchrotron radiation research at Daresbury Laboratory ,Warrington UK in 1970

Giorgio Margaritondo – one of the pioneers in the use of synchrotron radiation and free electron lasers

Gerd Materlik – former CEO of Diamond Light Source, the UK’s synchrotron science facility

Lightsources.org is hugely grateful to all the speakers, special guests and attendees who contributed to this event and made it such a special anniversary celebration for the light source community.

If you have any feedback or memories to share, please do contact Silvana Westbury, Project Manager, at webmaster@lightsources.org

For news, jobs, events and proposal deadlines, please visit the homepage

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!

How to get chloride ions into the cell

For the first time, a molecular movie has captured in detail the process of an anion transported across the cell membrane by a light-fueled protein pump. Publishing in Science, the researchers utilized the unique synergy of a Free Electron Laser (SwissFEL) and synchrotron light source (SLS) offered by PSI to unravel the mystery of how light energy initiates the pumping process − and how nature made sure there is no anion leakage back outside.

Many bacteria and unicellular algae have light-driven pumps in their cell membranes: proteins that change shape when exposed to photons such that they can transport charged atoms in or out of the cell. Thanks to these pumps, their unicellular owners can adjust to the environment’s pH value or salinity.

One such bacteria is Nonlabens marinus, first discovered in 2012 in the Pacific Ocean. Among others, it possesses a rhodopsin protein in its cell membrane which transports chloride anions from outside the cell to its inside. Just like in the human eye, a retinal molecule bound to the protein isomerizes when exposed to light. This isomerization starts the pumping process. Researchers now gained detailed insight into how the chloride pump in Nonlabens marinus works.

The study was led by Przemyslaw Nogly, once a postdoc at PSI and now an Ambizione Fellow and Group Leader at ETH Zürich, in close collaboration with the ALVRA team at SwissFEL and the MX team at the SLS. It is one of the first studies to fully combine experimental capabilities at these large-scale research facilities, bridging the gap in time resolution to record a full molecular movie of a protein at work. Slower dynamics in the millisecond-range were investigated via time-resolved serial crystallography at SLS while faster, up to picosecond, events were captured at SwissFEL – then both sets of data were put together.

Read more the PSI website

Image: Photoactive chloride pumping through the cell membrane captured by time-resolved serial crystallography: Chloride ions (green spheres) are transported across the cell membrane by the NmHR chloride pump (pink).

Credit: Guillaume Gotthard, Sandra Mous

Advancing materials science with the help of biology and a dash of dish soap

High-speed X-ray free-electron lasers have unlocked the crystal structures of small molecules relevant to chemistry and materials science, proving a new method that could advance semiconductor and solar cell development.

Compounds that form tiny crystals hold secrets that could advance renewable energy generation and semiconductor development. Revealing the arrangement of their atoms has already allowed for breakthroughs in materials science and solar cells. However, existing techniques for determining these structures can damage sensitive microcrystals.

Now scientists have a new tool in their tool belts: a system for investigating microcrystals by the thousands with ultrafast pulses from an X-ray free-electron laser (XFEL), which can collect structural information before damage sets in. This approach, developed over the past decade to study proteins and other large biological molecules at the Department of Energy’s SLAC National Accelerator Laboratory, has now been applied for the first time to small molecules that are of interest to chemistry and materials science.

Researchers from the University of Connecticut, SLAC, DOE’s Lawrence Berkeley National Laboratory and other institutions developed the new process, called small molecule serial femtosecond X-ray crystallography or smSFX, to determine the structures of three compounds that form microcrystal powders, including two that were previously unknown. The experiments took place at SLAC’s Linac Coherent Light Source (LCLS) XFEL and the SACLA XFEL in Japan.

Read more on the SLAC website

Image: Artist’s rendition of the X-ray beam illuminating a solution of powdered metal-organic materials called chalcogenolates.

Credit: Ella Maru Studios

Science that just can’t wait until morning!

We know by now that coffee ranks highly on the list of things that help get light source users through their night shifts. This #LightSourceSelfie also include insights on positive thinking that can provide a much needed boost to get you through to the morning. These insights are brought to you from staff scientists at LCLS and NSLS-II in the USA and Diamond in the UK.

That 1st light source experiment: The best way to understand is to experience!

Sae Hwan Chun, beamline scientist and condensed matter physicist at the PAL XFEL

Sae Hwan Chun is a beamline scientist and condensed matter physicist at the PAL XFEL is South Korea, one of the seven XFEL facilities in the Lightsources.org collaboration. Sae Hwan is able to research ultra-fast and dynamic phenomena in condensed matter by using the femtosecond X-ray pulses that XFELs generate.

In his #LightSourceSelfie, recalling his first synchrotron experiment at the Advanced Photon Source (APS), Sae Hwan said, “I thought that I understood how to do the experiment, but actually doing it was a completely different matter. It was like even though you pass a written exam for a driving license your mind goes blind to when you actually drive a car for the first time. This first day gave me a lesson that you should experience something if you want to understand it.”

Collaboration: a watchword for the light source community

Scientists Nina Perry and Nina Vyas, from Diamond Light Source (https://diamond.ac.uk – the UK’s synchrotron), along with SaeHwan Chun, scientist at the PAL-XFEL (https://pal.postech.ac.kr/paleng/ – the Free Electron Laser in South Korea) talk about a theme that is common to all light sources around the world, and indeed to science and all its associated disciplines. Cooperation and collaboration, and their benefits for scientists’ wellbeing as well as the science, are highlighted in this #LightSourceSelfie video.

Nina Perry & Ninya Vyas, on Beamline B24 at Diamond Light Source, the UK’s synchrotron science facility

Beginning your light source journey

Scientists who use synchrotrons such as the Advanced Light Source in California and CHESS at Cornell University, along with staff scientists at Free Electron Lasers in South Korea (the PAL-XFEL) and California (LCLS at SLAC), reflect on how they felt the first time they used a light source facility to conduct research experiments.  The expertise available from the staff scientists who work on the beamlines is also highlighted in this #LightSourceSelfie video.