Category: Swiss Light Source (SLS)

Measuring time at the quantum level

Measuring time at the quantum level

Physicists using the Swiss Light Source SLS have found a way to measure the time involved in quantum events and found it depends on the symmetry of the material.

“The concept of time has troubled philosophers and physicists for thousands of years, and the advent of quantum mechanics has not simplified the problem,” says Hugo Dil, a physicist at Paul Scherrer Institute PSI and professor at EPFL. “The central problem is the general role of time in quantum mechanics, and especially the timescale associated with a quantum transition.”

Quantum events, like tunnelling, or an electron changing its state by absorbing a photon, happen at mind‑bending speeds. Some take only a few tens of attoseconds (10-18 seconds), which is so short that light would not even cross the width of a small virus.

But measuring time intervals this small is notoriously difficult, also because any external timing tool can distort the very thing we want to observe. “Although the 2023 Nobel prize in physics shows we can access such short times, the use of such an external time scale risks to induce artefacts,” says Dil. “This challenge can be resolved by using quantum interference methods, based on the link between accumulated phase and time.”

Measuring quantum time without an external clock

Dil and his team from EPFL have now led research that has developed a way to accurately measure time in quantum events. When electrons absorb a photon and leave a material, they carry information in the form of their spin, which changes depending on how the underlying quantum process unfolds. By reading these tiny changes, the researchers could infer how long the transition takes, without ever using an external clock.

Read more on the PSI website

Image: Quantum events can unfold on attosecond timescales, making them notoriously difficult to measure. Researchers have now devised a way to measure the duration of quantum transitions without relying on an external clock.

Credit: © EPFL 2026/iStock (bymuratdeniz)

X-raying auditory ossicles – a new technique reveals structures in record time

X-raying auditory ossicles – a new technique reveals structures in record time

Scientists at the Paul Scherrer Institute PSI have refined an X-ray diffraction technique for detecting biological structures from nanometres to millimetres – reducing the time needed to make the measurement from around one day to about an hour. This opens up a wide range of possibilities for biomedical research – from analysing bone and tissue structures to supporting the development of new implants.

Biological materials are masterpieces created by nature. Bones, for example, are extremely hard, yet at the same time elastic enough to withstand lateral forces without breaking easily. This combination of properties results from their hierarchical structure as composite materials – they combine materials that have different structures on different scales. Human-made composite materials are similar in the way they are made up. In reinforced concrete, for example, the concrete component, consisting of cement and sand, can withstand high pressure, while a steel mesh provides high tensile strength and transverse stability. 

Until now, examining such biological materials in detail has required the use of several different instruments, such as electron microscopes or classic light microscopes. However, scientists at the PSI Center for Photon Science have now refined an X-ray diffraction technique that was developed at the institute ten years ago, allowing it to be used to characterise materials on scales from nanometres to millimetres simultaneously and much faster than before. A complete scan now only takes about an hour, instead of a whole day.

To demonstrate the efficiency of their method, the researchers used the Swiss Light Source SLS to reveal the alignment of collagen fibres in a human ossicle known as the incus, or anvil. Collagen fibres are thread-like protein structures that provide tensile strength and elasticity to bones. “In doing so, we have taken the leap from a scientific method to a practical technique,” says Christian Appel, postdoctoral researcher and first author of the study. The results have now been published in the journal Small Methods as its cover story. In future, this method could be valuable in areas such as the study of complex tissue, the analysis of bone diseases and the optimisation of implant designs.

Read more on the PSI website

Image: Scientists at PSI were able to observe the local collagen structures in an ossicle by scanning it with an X-ray beam. The different colours of the cylinders indicate how strongly the collagen bundles are spatially aligned in a section measuring 20 by 20 by 20 micrometres.

Credit: © Paul Scherrer Institute PSI/Christian Appel

X-rays bring high-resolution brain mapping within reach

X-rays bring high-resolution brain mapping within reach

Scientists at the Swiss Light Source SLS have succeeded in mapping a piece of brain tissue in 3D at unprecedented resolution using X-rays – non-destructively. The breakthrough overcomes a long-standing technological barrier that had limited the use of X-rays for such studies. With the SLS upgrade now complete, the path lies open to imaging much larger samples of brain tissue at high resolution – and to gaining new understanding of its complex architecture. The study, a collaboration between Paul Scherrer Institute PSI and the Francis Crick Institute in the UK, is published in Nature Methods.

“The brain is one of the most complex biological systems in the world,” says Adrian Wanner, who leads the Structural Neurobiology research group at Paul Scherrer Institute PSI. How neurons are wired together is what his group are trying to unravel – a field known as connectomics. 

He explains: “Take the liver: we know of about 40 cell types. We know how they are arranged. We know their functions. This is not true for the brain. And so, one could ask, what is the difference between the brain and the liver? If we look at a cell body in the brain and the liver, it’s not easy to distinguish the two. They both have a nucleus, an endoplasmic reticulum – they both have the same intercellular machinery, the same molecules, the same types of proteins. This is not the difference. What is really different is how the brain cells are organised and connected.”

Read more on the PSI website

Image: One cubic millimetre of brain tissue contains about 100 000 neurons, connected through some 700 million synapses and 4 kilometres of ‘cabling’. This complex 3D wiring underlies brain function – yet is extraordinarily difficult to study.

Credit: © Adobe Stock

How the cheese-noodle principle could help counter Alzheimer’s

How the cheese-noodle principle could help counter Alzheimer’s

Researchers at the Paul Scherrer Institute PSI have clarified how spermine – a small molecule that regulates many processes in the body’s cells – can guard against diseases such as Alzheimer’s and Parkinson’s: it renders certain proteins harmless by acting a bit like cheese on noodles, making them clump together. This discovery could help combat such diseases. The study has now been published in the journal Nature Communications.

Our life expectancy keeps rising – and as it does, age-related illnesses, including neurodegenerative diseases such as Alzheimer’s and Parkinson’s, become increasingly common. These diseases are caused by accumulations in the brain of harmful protein structures consisting of incorrectly folded amyloid proteins. Their shape is reminiscent of fibres or spaghetti. To date, there is no effective therapy to prevent or eliminate such accumulations.

Yet a naturally occurring molecule in the body called spermine offers hope. In experiments, researchers led by study leader Jinghui Luo, in the Center for Life Sciences at the Paul Scherrer Institute PSI, have discovered that this substance is capable of extending the life span of small nematode worms, improving their mobility in old age, and strengthening the powerhouses of their cells – the mitochondria. Specifically, the researchers observed how spermine helps the body’s immune system eliminate nerve-damaging accumulations of amyloid proteins. 

The new findings could serve as a basis for developing novel therapies for such diseases.

A central mediator of cellular processes

Spermine is a vital substance for the organism. It belongs to the so-called polyamines, which are relatively small organic molecules. Spermine, first discovered more than 150 years ago, is named after the seminal fluid, as it is found in particularly high concentrations there. But it also occurs in many other cells of the body – especially those that are active and capable of dividing.

Spermine promotes cell mobility and activity and controls numerous processes. Above all, it interacts with the nucleic acids of the genome, regulating the expression of genes and their conversion into proteins. This ensures that cells can properly grow and divide and ultimately die. Spermine is also central to an important cellular process called biomolecular condensation: In this process, certain macromolecules, such as proteins and nucleic acids, segregate and collect within the cell in a droplet-like form, so that important reactions can take place there.

In connection with neurodegenerative diseases such as Alzheimer’s or Parkinson’s, there has previously been evidence that spermine can protect nerve cells and alleviate age-related memory loss. Lacking until now, however, has been a more precise understanding of how spermine intervenes in nerve-damaging processes – understanding that might make it possible to derive medical benefits from it.

Assisting cellular waste removal

Jinghui Luo’s group has now investigated this in more detail. In addition to optical microscopy, the researchers also used the SAXS scattering technique at PSI’s Swiss Light Source SLS to shed light on the molecular dynamics of these processes. The investigations were conducted both in a glass capillary (in vitro) and in a living organism (in vivo). The nematode C. elegans served as a model organism.

Read more on the PSI website

Image: Jinghui Luo is a researcher at the Center for Life Sciences at the Paul Scherrer Institute PSI. He studies accumulations of so-called amyloid proteins, which lead to nerve damage in the brain. His research aims to help mitigate neurodegenerative diseases such as Alzheimer’s and Parkinson’s in the long term.

Credit: © Paul Scherrer Institute PSI/Markus Fischer

Big heart, acute senses key to explosive radiation of early fishes

Big heart, acute senses key to explosive radiation of early fishes

At the Swiss Light Source SLS, X-ray tomographic microscopy of tiny, 400-million-year-old fish shows how anatomy geared toward evading predators equipped it to become the hunter once jaws evolved. 

An international team led by scientists from the Canadian Museum of Nature and the University of Chicago reconstructed the brain, heart, and fins of an extinct fish called Norselaspis glacialis from a tiny fossil the size of a fingernail. They found evidence of change toward a fast-swimming, sensorily attuned lifestyle well before jaws and teeth were invented to better capture food. 

“These are the opening acts for a key episode in our own deep evolutionary history,” said Tetsuto Miyashita, research scientist at the Canadian Museum of Nature and lead author of the new study published in the journal Nature.

Jaws changed everything – but maybe not first

Fish have been around for half a billion years. The earliest species lived close to the seafloor, but when they evolved jaws and teeth, everything changed; by 400 million years ago, jawed fishes dominated the water column. Ultimately, limbed animals – including humans – also originated from this radiation of vertebrates.

It has long been a mystery, however, how this pivotal event occurred. The standard theory holds that jaws evolved first, and other body parts underwent changes to sustain a new predatory lifestyle. “But there is a large data gap beneath this transformation,” said Michael Coates, Professor and Chair of Organismal Biology and Anatomy at the University of Chicago and a senior author of the study. “We’ve been missing snapshots from the fossil record that would help us order the key events; to reconstruct the pattern and direction of change.”

The new study flips the “jaws-first” idea on its head. “We found features in a jawless fish, Norselaspis, that we thought were unique to jawed forms,” said Miyashita, who was formerly a postdoctoral fellow in Coates’ lab in Chicago. “This fossil from the Devonian Period more than 400 million years ago shows that acute senses and a powerful heart evolved well before jaws and teeth.”

But the team also needed a chance encounter and a special tool to gain these insights into the inner workings of Norselaspis.

Synchrotron X-rays reveal ghosts of organs never seen before

The fossil of Norselaspis the team studied is so exquisitely preserved in a fragment of rock that they were able to scan it and see impressions of its heart, blood vessels, brain, nerves, inner ears, and even the tiny muscles that moved the eyeball. The fossil was hidden in one of thousands of sandstone blocks collected during a French paleontological expedition to Spitsbergen, Norway’s Arctic Archipelago, in 1969. 

Sorting through these rocks 40 years later, the study’s co-authors Philippe Janvier and Pierre Gueriau split one open, revealing a perfectly preserved cranium of Norselaspis barely half an inch long. The team took the fossil to Switzerland to scan it with high-energy X-ray beams at the TOMCAT beamline of the Swiss Light Source SLS.

“We used a technique known as X-ray tomographic microscopy,” said Federica Marone, TOMCAT beamline scientist at the SLS. “This allowed us to non-destructively study the 3D details of the fossil at very high resolution, and gain insights that have never been seen before,” 

The result was jaw-dropping. Slice by slice, the X-ray images revealed with astonishing detail delicate bone membranes that enclosed the fish’s organs. These tissue-thin bones capture the ghosts of organs formerly held by the skeleton. 

“Making use of the tiny refraction of the X-ray beam going through the sample, in addition to its commonly used absorption, we have been able to boost the contrast between similar tissues,” explains Marone. “This enabled us to image these tiny bones, only a hundredth of a millimetre wide, which show the imprints of now lost organs.”

Read more on SLS website

Image: Norselaspis glacialis was a jawless fish from the Devonian period 400 million years ago, which had anatomical features such as a larger heart and sensory organs that allowed later fish to adapt to a predatory lifestyle once jaws evolved.

Credit: Kristen Tietjen, University of Kansas

A bright light for Switzerland: The new Swiss Light Source is inaugurated

A bright light for Switzerland: The new Swiss Light Source is inaugurated

The Swiss Light Source SLS upgrade at the Paul Scherrer Institute PSI will accelerate the path from scientific discovery to practical applications – ones that span healthcare, climate, energy, and future technologies. Present at its inauguration on the 21 August 2025 is Federal Councillor, Guy Parmelin. 

On the 21 August 2025, the Paul Scherrer Institute PSI inaugurated its newly upgraded Swiss Light Source SLS. Around 150 guests from politics, business and science were present to celebrate the achievement, including Federal Councillor Guy Parmelin and Martina Bircher, member of the cantonal government and Head of the Department of Education, Culture and Sport of the Canton of Aargau. 

The new SLS is one of the most ambitious science infrastructure projects in Switzerland – one that will enable experiments that were previously unthinkable. “The SLS was at its inception and is now after its comprehensive upgrade a national infrastructure built for the common good,” said PSI Director Christian Rüegg. “It is a tool for Swiss researchers and industry, and for our international guests to answer questions that matter for the future of people and the planet.”

The SLS is Switzerland’s national synchrotron light source – a huge X-ray microscope shaped like a doughnut. Scientists from all of Switzerland and around the world travel to the SLS to use the light, billions of times brighter than that of a hospital X-ray, to peer deep into proteins, cells and tissues, materials, and molecules with atomic resolution.

At the inauguration event, Christian Rüegg reflected on the visionary construction of the SLS in 2001 – at the time, one of the first national synchrotrons in the world. Now, it is the first national facility in the world to upgrade to the next generation of technology. With light many times more intense than before, it will accelerate the path from scientific discovery to practical applications – ones that span healthcare, climate, energy, and future technologies.

Guy Parmelin described the new SLS as a significant milestone for Switzerland as a centre for research and innovation. He pointed out that the SLS embodies the qualities that define Switzerland: long-term vision, perseverance and innovative strength. The upgrade reinforces the nation’s reputation as a global hub for cutting-edge science and technology and sends a strong and positive signal that Switzerland invests in its future. 

A 288m ring built to the precision of a Swiss watch

An amazing feat of engineering, saving many tens of millions of francs, was to install the new machine within the old building. Central to this is the new storage ring in which electrons whizz round at close to the speed of light, producing X-rays. This ring – with all its custom-made components from magnet systems to vacuum chambers – was painstakingly designed to fit perfectly within the existing building. 

“We built a ring with a 288m circumference to the precision of a Swiss watch – and completed it on schedule like a Swiss train,” said SLS 2.0 project leader Hans Braun. “The upgrade is a masterpiece of science, engineering and planning.” 

The light that it produces may be much more intense, but the upgrade also uses 33% less electricity than before. Such savings stem from state-of the-art engineering choices that make the operation more efficient, plus a new solar panelled roof.

Hans Braun added: “We set our sights high. Our goal was to create a new machine that pushes the boundaries of technology – and we achieved it.” 

A cutting-edge machine for Switzerland

The audience were tempted with some of the scientific offerings that the new machine will bring in a panel discussion entitled ‘Illuminating the Future of Science and Innovation’. Participating were leading voices in science and industry from Switzerland, the UK and Germany. 

Thanks to the upgrade, SLS experiments benefit from light up to 1000 times more intense than before. For some experiments, this will mean that samples that once took days can be imaged in minutes. For others, it will mean accessing tiny details of nature or materials never seen before. In other cases, entirely new research will be possible.

Diverse applications will benefit. Some of the examples discussed include imaging brain tissue at high resolution in 3D – an important development for understanding neurodegenerative diseases such as Alzheimer’s. Imaging computer chips at the nanoscale is driving innovation in the semiconductor industry and is important for national security. Applications that improve the performance of catalysts were also discussed. Of particular importance to Jörg Duschmalé, board member from Roche, was that the SLS upgrade will allow some of the most interesting protein structures to finally be studied and new molecules for medical treatments to be developed.

The celebration of an enormous engineering effort

For those behind the upgrade, the inauguration was a moving occasion: in September 2023, the light was switched off at SLS for just over one year so that the electron storage ring could be dismantled and entirely replaced. Over 4000 tonnes of concrete were removed – and later put back in place. To form the new ring, PSI engineers installed 500 copper vacuum chambers and 1000 high-precision magnet systems – designed and tested on-site, together with countless pipes and tubes, cooling systems, vacuum pumps, and a total of around 500 kilometres of cables. 

Read more on SLS website

X-rays reveal fossil stealth technology

X-rays reveal fossil stealth technology

Using state-of-the-art X-ray microtomography at the Swiss Light Source SLS, operated by the Paul Scherrer Institute PSI, researchers have gained insights into the silent hunting techniques of a giant ichthyosaur – a marine predator that roamed the dimly lit oceans 183 million years ago.

In the twilight of the Jurassic period, a giant ruled the seas: Temnodontosaurus, an ichthyosaur that was more than ten metres long, with eyes the size of footballs. It glided virtually noiselessly through the dark waters – always on the lookout for prey. This marine predator relied on specialised stealth strategies: no eddies, no noise – advancing silently before making a lightning attack.

What may sound like a scene from a wildlife documentary is actually based on the latest scientific findings. An international research team led by Johan Lindgren from Lund University has managed, for the first time, to analyse the soft tissue structures of an exceptionally well-preserved forefin of one of these marine giants. The structure of the forefin suggests an evolutionary adaptation to suppress noise when swimming – comparable to the serrated flight feathers of an owl, which glides through the night almost without a sound. In order to determine the detailed structure of the soft tissue, the Temnodontosaurus’s forefin was sent on a journey – to undergo X-ray tomography at the Swiss Light Source SLS in Villigen.

From land animal to silent leviathan

Ichthyosaurs lived on Earth between 250 and 90 million years ago, making them one of the most successful groups of marine tetrapods – four-limbed vertebrates – that we know of. Like modern whales, these ancient aquatic reptiles descended from land-dwelling animals that gradually adapted fully to life in the ocean by developing fins and streamlined, almost dolphin-like bodies.

The new study, published in the journal Nature, describes an almost complete forefin of the largest ocean megapredator during the Early Jurassic. “The wing-like shape of the flippers, the absence of bones at the distal end – the part furthest from the body – the longitudinal skin structures and the distinctly jagged trailing edge indicate that this massive animal had developed means of minimising noise when swimming,” explains Johan Lindgren, the study’s lead author, who specialises in the analysis of fossilised soft tissues in marine reptiles. This means that the ichthyosaur must have moved through the water almost noiselessly. “We have never before seen such sophisticated evolutionary adaptations in a marine animal.”

Although many unusual ichthyosaurs have been found in which the soft tissue has been preserved, even including some with complete body outlines, the known soft parts have so far been restricted to a small group of dolphin-sized species. The new discovery is remarkable in that it represents the first soft tissue of a large ichthyosaur. Also, the structure of the flipper is unlike that of any other known aquatic animal, living or extinct. Its jagged rear edge is reinforced by novel rod-like mineralised structures, which the team refers to as “chondroderms”. The fossilised fin was discovered by chance at a road construction site near Dotternhausen in southern Germany – by fossil collector Georg Göltz, a co-author of the study, who was looking out for other fossils there.

High-tech methods reveal prehistoric stealth technology

To better understand the structures preserved in the fossil, the fin underwent a series of highly sensitive procedures. Synchrotron-based X-ray microtomography at the TOMCAT beamline of the SLS at PSI played a key role. “The high resolution and high contrast of our tomography procedure meant that we were able to visualise the fine internal structure of the chondroderms in three dimensions,” says Federica Marone, a beamline scientist at PSI’s Center for Photon Science. “This imaging technique was crucial to helping us understand the mechanical function of the rod-like reinforcements –particularly their role in minimising noise while swimming.”

Read more on SLS website

Image: This is what the silent Jurassic hunter might have looked like: Temnodontosaurus in action.

Credit: Adobe Stock

Zinc detected in clogged syringes

Zinc detected in clogged syringes

Employees of the technology transfer centre ANAXAM and researchers from the Paul Scherrer Institute PSI used the unique analytical methods available at PSI to look inside pre-filled syringes. They found that, in rare cases, zinc from the needle shield can leach into the drug solution to be injected and possibly contribute to syringe clogging.

The task which the employees of the technology transfer centre ANAXAM set themselves, together with colleagues at the Paul Scherrer Institute PSI, can be likened to looking for a needle in a haystack. They were asked by the pharmaceutical company MSD (a trade name of Merck & Co., Inc., Rahway, N.J., USA) to find out whether tiny amounts of the element zinc can get inside the needles of pre-filled syringes and, if so, where it lodges in the needles.

The background is the observation that, in rare cases, the needles of pre-filled syringes (PFS) can become blocked, for example if the syringes are not stored in a cool enough environment. This phenomenon has been known for some time and has already been studied by ANAXAM. However, what has remained unclear is exactly what triggers the blockage. One suggestion was that zinc from the needle shield – the rubber cap into which the needle is inserted when the syringe is manufactured – could leach into the drug solution to be injected, making it more viscous, which would ultimately lead to blockages. 

To investigate this theory, the team led by ANAXAM has now resorted to sophisticated methods of detection. These allowed them to look inside the blocked hypodermic needles and check whether and where zinc was present. The results have now been published in the journal Pharmaceutical Research. 

Convenient pre-filled syringes

Pre-filled syringes are widely available, practical and easy to use, both for healthcare professionals and for patients. The amount of solution to be injected is precisely measured, which virtually rules out dosing errors, for example. The fact that their needles can become clogged, especially when the solution to be injected is highly concentrated, is a well-known issue in the pharmaceutical industry and has also been raised during licensing applications. There have also been cases of clogged needles which have led to products being recalled. “So Merck was very interested in knowing whether zinc could in fact find its way into the needles and cause the blockage,” says Vlad Novak, project manager at ANAXAM. 

This meant that several questions had to be answered. Is there zinc inside the needle? And if so, where do they come from? What does the inside of a clogged needle look like? And is the zinc also present in the solution being injected, which could ultimately lead to the blockage?

Read more on the PSI website

Image: Employees of the technology transfer centre ANAXAM and researchers at the Paul Scherrer Institute PSI used the unique analytical methods available at PSI’s large research facilities to look inside pre-filled syringes.

Credit: © Adobe Stock

Aluminium made visible

Aluminium made visible

Zeolites are highly porous substances that facilitate numerous reactions in the chemical industry. In collaboration with the J. Heyrovský Institute of Physical Chemistry in Prague, PSI researchers have succeeded for the first time in precisely determining the position of the aluminium atoms in the zeolite lattice – an important step on the path to tailor-made catalysts. The study has now been published in the journal Science.

In cat litter they absorb unpleasant odours; in detergents they soften the water, protecting washing machines; and in refineries they help in the production of petrol – zeolites are used in many different places. We encounter them in our daily lives, and they are the most frequently used catalysts for promoting chemical reactions in industry. 

Their many useful properties stem from their porous, lattice-like structure. Silicon and aluminium atoms are linked by oxygen atoms to form a crystalline framework with numerous small pores and channels. Zeolites can capture molecules from gases or liquids, hold on to them and help to convert them into other molecules. But it is only now that PSI researchers have managed to draw a more precise picture of a zeolite structure: they have located the position within the lattice of the aluminium atoms that trigger the chemical reactions.

“Zeolites are extremely important materials, but we still don’t fully understand how they work,” says Jeroen van Bokhoven of PSI’s Center for Energy and Environmental Sciences. Previous methods were able to determine the position of the atoms in the lattice but could not distinguish aluminium from silicon. The aluminium atoms play a particularly important role, however: they form the active sites that allow certain reactions to take place. This is why scientists are particularly interested in locating them. 

The exact position of the aluminium atoms determines how effective the zeolite in question is as a catalyst and for which chemical reactions. Different zeolite structures are used for different reactions. The PSI researchers used their method to investigate the zeolite ZSM-5, a particularly important industrial catalyst with an unusually complex structure. “We reckoned that if we could do this with ZSM-5, the other zeolites wouldn’t be a problem,” says Jeroen van Bokhoven.

The SLS as a large microscope

The question of where exactly the aluminium atoms are located in the zeolite structure has long vexed scientists. “The new method we have developed solves a problem that previously seemed unsolvable,” says Przemyslaw Rzepka, first author of the study. Rzepka, who used to work with Jeroen van Bokhoven at PSI as a postdoc, is now a scientist at the J. Heyrovský Institute of Physical Chemistry in Prague. 

Until now, scientists have used ordinary X-rays to look inside zeolites and learn about the structure of their pores and channels. The X-rays are scattered by the atoms and the resulting diffraction pattern allows conclusions to be drawn about the three-dimensional structure of the material. The problem is that the elements silicon and aluminium are right next to each other in the periodic table, and this means that in experiments using ordinary X-rays they look more or less identical. Spectroscopic methods, on the other hand, rely on the way a material absorbs radiation or alters it. Because aluminium and silicon absorb radiation differently, the two types of atoms can be distinguished – however, such methods cannot determine their positions in space, only the number and type of atoms in a material.

The PSI scientists’ solution was to combine the two techniques. They directed soft X-rays, which have comparatively low energies, at the materials at the Swiss Light Source SLS. “The pattern created when the X-rays are scattered by the material tells us the position of the atoms. We then examine these positions using spectroscopic methods to identify the particular type of atom that is sitting there,” explains Przemyslaw Rzepka. 

This clever combination was made possible by the unique X-ray diffractometer for soft X-rays at the SLS Phoenix beamline. The researchers were able to see, for the first time, a difference between silicon and aluminium atoms and determine the exact location of the active sites where the reaction takes place.

Read more on PSI website

Image: Jeroen van Bokhoven (left) and his team at the Paul Scherrer Institute PSI in Villigen are carrying out research into zeolites. His research group has succeeded for the first time in determining the position of the aluminium atoms that are crucial to the catalytic properties of the materials. This was possible thanks to the Swiss Light Source SLS, where scientist Thomas Huthwelker (right) works.

Credit: Paul Scherrer Institute PSI/Markus Fischer

A superlative milestone

A superlative milestone

PSI spin-off Araris Biotech AG is being acquired by the multinational pharmaceutical company Taiho Pharmaceutical Co., Ltd. The total value of the deal comes to USD 1.14 billion – making Araris the first PSI spin-off to achieve the exclusive unicorn-level!

The deal includes an initial payment  of $400 million and milestone payments of a further $740 million, bringing the total deal size to $1.14 billion. Contract structures like this are typical for the acquisition of companies in the biotech sector. The term ‘unicorn’ is used in the business world to describe something very special: a start-up that has achieved a valuation of over 1 billion US dollars.

With this deal, the start-up Araris, which was spun out of the Paul Scherrer Institute PSI in 2019, will now be fully acquired by Taiho Pharmaceutical Co. The total value of this acquisition confirms the innovative potential of Araris’ therapeutic approach, which aims to improve the efficacy and tolerability of cancer therapies.

Araris Biotech AG develops novel antibody-drug conjugates (ADCs) for the targeted treatment of cancer. The company was founded by Philipp Spycher, building on research carried out at PSI’s Center for Radiopharmaceutical Sciences. Spycher developed a method that allows cytotoxic agents to be bound to antibodies more firmly than before. In this technology, the antibody delivers the drug specifically to the diseased tissue, where it destroys the tumour cells. This work led to several patent applications and PSI’s own funding programme “PSI Founder Fellowship” supported him as he refined his research and developed a business idea. The concept convinced notable investors. Hence, the acquisition is a huge success not only for Araris Biotech AG, but also for PSI.

The technology transfer team at PSI supported Spycher on his journey from “researcher to entrepreneur” and ultimately helped him set up the spin-off Araris Biotech AG. PSI promotes spin-offs and with them the commercialisation of know-how and technologies developed at PSI that benefit society in the form of new products or services. “Spin-off companies are of strategic importance to PSI, because they bring the know-how gathered here to the market very efficiently, increase the visibility of PSI and contribute to strengthening the Swiss economy,” says John Millard, Head of Technology Transfer at PSI. Successful spin-offs also strengthen the innovative power of the Canton of Aargau and create new jobs. 

Read more on PSI website

Image: Araris Biotech AG develops novel antibody-drug conjugates for the targeted treatment of cancer. Shown here: an antibody-drug conjugate attached to two active drugs. The Araris technology allows the two drugs (orange and blue) to be attached to the antibody (turquoise) simultaneously by means of the so-called linker (yellow).

Credit: Araris Biotech AG

Targeted funding of innovation for the energy transition

Targeted funding of innovation for the energy transition

LED lamps have seen rapid advances in recent years. PSI researcher Michael Weinold has been studying how this progress came about. One of the causes is spillover effects. These accelerate innovation and are important for the transformation of the energy system – and they can be deliberately promoted.

How do innovative ideas arise? If we knew the answer, we could produce a stream of new technologies. However for the most part, technological progress cannot be planned or else it follows a surprisingly circuitous path. Light-emitting diodes, or LEDs, are a particularly good example of this.

Michael Weinold is now a PhD student at the Laboratory for Energy Systems Analysis at PSI and the laboratory of the same name at ETH Zurich, working with Professor Russell McKenna. For his master’s thesis at the University of Cambridge and ETH Zurich he studied the rapid development of LEDs. He found that spillover effects were an important factor. In research, this term is used to describe advances or technologies that were originally developed for entirely different industries or products. The effect is particularly striking in the case of LEDs, as Weinold demonstrates in his paper. “Above all, the crucial improvement in the quality of the light is largely due to spillover effects,” says Weinold.

Michael Weinold’s research was conducted during his time as a visiting researcher at the Cambridge Centre for Environment, Energy and Natural Resource Governance (C-EENRG), in collaboration with Sergey Kolesnikov and Laura Diaz Anadon at the University of Cambridge. The work was part of a larger research project funded by the Alfred P. Sloan Foundation at the University of Cambridge, Harvard University and the University of Minnesota. The project set out to understand how innovation occurs in the energy system and how this process can be specifically accelerated by investing in fundamental research so as to reduce the energy consumption and emissions of new technologies.

Chance and targeted promotion

For decades, LEDs led a niche existence as red indicator lights on electrical appliances. That was until 1992, when Shuji Nakamura and his team came up with the first blue LED, the basis for today’s white LEDs and hence LED lighting in general. The scientists were awarded the Nobel Prize in Physics in 2014 for their work. Since then, there have been rapid improvements in production costs, efficiency and, above all, light quality. The cool LED light of the early days has given way to a pleasantly warm light, whereby the colour of the light can now be freely adjusted.

An example of a spillover effect for LEDs is indium tin oxide (ITO), a material that conducts electricity but is also transparent to light. It has long been used in the aviation industry to heat cockpit windows and so prevent ice from forming. Conductive and transparent – that was exactly what the developers of LEDs needed, and so ITO quickly found its way into their products.

“The great thing about spillover is that it’s free,” says Weinold, because the technology has already been developed and can often be used straight away in other areas. A spillover is often helped by chance. LEDs generate white light from blue light, which is converted by a thin phosphor coating. However, in the early days of LEDs, the only available phosphors produced a cool white light. It was not until a chance conversation between two professors at a conference that the door was opened for a spillover in phosphors. Since then, LEDs have also been able to produce a pleasant warm white light.

The catch is that if spillovers are not to be left to chance, researchers need to know exactly what they are looking for. For example, as long as the fundamental physical effects taking place in a diode are not fully understood, it is not possible to look for specific solutions that will produce higher efficiencies.

According to Weinold, this leads to an insight which ought to be of great interest particularly to those funding research. In order to accelerate the development of new technologies through spillover effects, it is necessary to specifically promote fundamental research. Ideally in those areas where physical or chemical mechanisms are not yet fully understood. Weinold explains: “Once the fundamental principles of a new technology have been properly studied, spillover effects are almost inevitable.”

The future of LEDs

It will be interesting to see how LEDs continue to evolve – if they do at all. In his research, Weinold found that almost all the physical processes involved in generating light with LEDs have come close to their theoretical maximum efficiency in recent years. The development of conventional LEDs could therefore slow down considerably over the coming years.

Nobel Prize winner Shuji Nakamura seems to have anticipated this. He has abandoned the development of conventional LEDs and is now conducting research into laser LEDs, a field in which considerable gains in efficiency are still expected. And major manufacturers such as Osram and Philips are focusing on developing special applications such as micro-LEDs for VR headsets. On the other hand, certain processes in LEDs have already achieved efficiencies of over 100 percent thanks to quantum mechanical effects. So further surprises should not be ruled out.

Read more on PSI website

Image: Spillover effects have led to rapid advances in the technology used for white light LEDs. Specifically funding fundamental research could increase similar effects in other areas, thereby accelerating innovative solutions for transforming the energy system. Michael Weinold from PSI has investigated how such spillover effects can be promoted.

Credit: Paul Scherrer Institute PSI/Mahir Dzambegovic

A faster route to green hydrogen

A faster route to green hydrogen

Acidic conditions are a challenge. If you want to produce hydrogen by electrolysis and use a low-cost catalyst such as cobalt, the process doesn’t function as well if the aqueous environment is acidic – working in alkaline conditions is easier. Researchers at the Paul Scherrer Institute PSI have now discovered the reason for this: the surface of the catalyst changes with the pH value of the environment. Their study, published in the journal Nature Chemistry, provides important clues to enable efficient and cost-effective production of hydrogen for the energy transition in the future.

The simplest and most environmentally friendly method for producing hydrogen is electrolysis: with an electric current, water (H2O) is split into its components, hydrogen (H2 ) and oxygen (O2). Oxygen is produced at the positive pole, the anode; hydrogen is produced at the negative pole, the cathode. Water splitting can be carried out in an alkaline environment (pH>7), an acidic one (pH<7), or a neutral one (pH=7). Different types of electrolysers operate at different pH values, that is, in different aqueous environments.

In splitting water, the formation of oxygen is the step that requires the most energy, effectively the bottleneck of the reaction. To make it possible to do this more efficiently and cost-effectively, catalysts such as the metal cobalt are used. However, electrolysis with cobalt only works satisfactorily in an alkaline environment; the reason for this was previously unknown.

A PSI research group in the Center for Energy and Environmental Sciences have now found out the cause: depending on the pH value, the catalyst’s surface changes. In acidic conditions, active sites where oxygen can be produced require more energy to form – as a result, electrolysis becomes slow and uneconomical. “We assume that this is the case not only with cobalt, but also with other metals that likewise perform less well in acidic conditions – such as manganese, iron, and nickel,” says Jinzhen Huang, a postdoctoral researcher in Emiliana Fabbri’s and Thomas Schmidt’s research group and first author of the study.

Cobalt as a low-cost alternative

At present, the noble metals iridium and ruthenium are usually used as catalysts for splitting water. Their activity changes only slightly depending on the pH value and therefore also work well in acidic environments. However, cobalt and other so-called transition metals are significantly cheaper and more abundant on Earth, which makes them particularly attractive for large-scale applications. “Replacing the noble metals with cobalt and other lower-cost metals is a major challenge,” Emiliana Fabbri explains. “Our findings are important steps on the way to that goal.”

Read more on PSI website

Image: Close-up of a glass vial containing a cobalt-based catalyst powder, captured in the lab at the Paul Scherrer Institute PSI. Researchers at the PSI Center for Energy and Environmental Sciences have discovered why this catalyst performs more efficiently in alkaline environments during hydrogen production.

Credit: Paul Scherrer Institute PSI/Mahir Dzambegovic

Creating circuit diagrams of the brain

Creating circuit diagrams of the brain

Adrian Wanner aims to map the brain’s architecture. Doing this will allow us to better understand neurodegenerative diseases like Alzheimer’s.

Do you know this situation? You are standing in the kitchen and suddenly don’t remember why you went in there in the first place. Working memory is at fault here. It is supposed to keep information available for us for a period of several minutes. “If it isn’t working properly, it can lead to situations just like this one, where you forget whatever it was you wanted to do,” explains Adrian Wanner, a neurobiologist at the Laboratory of Nanoscale Biology at the PSI Center for Life Sciences (CLS).

In everyday life, situations like this might be unpleasant, but tend to be ultimately harmless. For some people, however, they may indicate a more serious underlying issue, as Adrian Wanner explains: “In the case of Alzheimer’s, working memory is often the first thing to be affected. Long before pathological changes like protein deposits in the brain become clearly visible, patients experience this type of forgetfulness.” Understanding working memory and its structure in detail could thus contribute to better comprehension of the terminal illness Alzheimer’s.

Activity maps and circuit diagrams

In order to reconstruct what exactly happens when the working memory keeps information available, Wanner uses two methods. “First, we create activity maps of brain cells,” the neurobiologist explains. “In these diagrams, the neurons that are activated by a particular action light up in colour.” 

The researchers then try to find out how the individual neurons in this area are linked. “It’s like a circuit diagram for a computer,” says Wanner – but with biological synapses instead of electrical connections. Most brain regions and functions have not yet been mapped by way of such a circuit diagram that describes how information is processed: “Does information go directly from point A to point B to point C or are there cross connections or feedback loops in between that move it a step back?” 

There are various, often conflicting theories on which paths the brain activates when it processes and then stores information. Adrian Wanner wants to use empirical data to determine which model best reflects reality. He wants to observe which neurons are active during tasks for which working memory is important. He then maps the way in which these neurons are interlinked to create a detailed circuit diagram. “This way, we can track exactly what is happening in the brain at this point in time.”

The working memory at work

For his research, Adrian Wanner works with mice. “In terms of structure and function, their brains are similar to those of humans’,” he explains. “This is why they can also develop forms of dementia and we can analyse how healthy animals differ from sick ones.”

In order to analyse a mouse’s working memory, the neurobiologist sets it a task where the mouse has to remember information for a few seconds. First, the mouse learns how to move around in a virtual environment, similar to a computer game. To do this, the animal watches a screen and runs along a virtual corridor. At the beginning of the corridor, the mouse is shown a specific pattern, for example a checkerboard pattern. It must then remember this pattern. 

After a few metres, the corridor forks into a left-hand and a right-hand path. Once the mouse arrives at this point, a pattern is displayed at each path, a line pattern on the right and a checkerboard pattern on the left, for instance. Now, the mouse has to recall: “Aha! There was also a checkerboard pattern at the beginning of the corridor.” If it turns left at the virtual fork, it receives a real reward in the form of food. “It is precisely during this period, when the mouse is no longer looking at the pattern and is running along the corridor, that it must keep the information available – its working memory is active.”

While the mouse is playing this memory game, Wanner and his team are imaging the activity in its brain. By comparing these images to circuit diagrams of the brain, they can determine the rules according to which the neurons are linked in order to keep this piece of information in working memory. “In fact, brain activity differs depending on the pattern that we show the mouse. A checkerboard pattern causes different cells to activate in a different sequence than a line pattern.”

Read more on PSI website

Image: Tiny section of a mouse brain: a few dozen nerve cells with their synapses are shown, and thus only a fraction of the 100 000 cells that cavort in a cubic millimetre of brain.

Credit: MICrONs Consortium et al.

SLS 2.0: How to start up a particle accelerator

SLS 2.0: How to start up a particle accelerator

The upgrade of the Swiss Light Source SLS, one of the large research facilities of the Paul Scherrer Institute PSI, is moving ahead: the electrons are back now in the completely new electron storage ring. A report from the SLS control room.

To switch on a large machine, just pressing a button is usually not enough. And the Swiss Light Source SLS is quite a remarkable machine: an accelerator-based large research facility that will soon resume producing high-intensity X-ray light for around 20 experiment stations at the Paul Scherrer Institute PSI. Thanks to the SLS 2.0 upgrade and a significantly slimmer electron beam, this light will be many times brighter and thus will enable better research than ever before. Now it is the beginning of 2025, and the facility is being awakened from its 15-month sleep. Step by carefully considered step.

“We tested the linear accelerator and the booster before Christmas and got them running again fairly quickly, which was encouraging,” says Jonas Kallestrup. He is an accelerator physicist who did his PhD at SLS, then worked at the Diamond Light Source in the United Kingdom for a few years and is now back at PSI since 2022. His main responsibility here is for the booster he mentioned: after the linear accelerator, this is the part of SLS that brings the electrons up to nearly the speed of light. From there they have to be brought into the electron storage ring. And from here, it gets exciting.

That’s because the electron storage ring, with a circumference of 288 metres, is brand new. As part of the SLS 2.0 upgrade project, it was replaced starting in October 2023. This means: a new vacuum tube within which the electrons can speed around almost undisturbed; a new, sophisticated arrangement of around 1,000 high-performance magnets along the ring, surrounding the vacuum tube to keep the electrons on their precise course; and new associated pipes and tubes, cooling systems, vacuum pumps, and a total of around 500 kilometres of cables to connect everything.

A landscape of number columns and diagrams

Kallestrup is part of the commissioning team, which these days is working with great concentration in the PSI control room in the building next to the SLS. Five to ten people typically sit here, some of whom were already part of the team when SLS was first commissioned in 2001. Eighteen large computer screens, each with a dozen application windows, are set up in a semicircle. Together they show a neatly arranged landscape of number columns and diagrams, enabling the team to keep an eye on the relevant parameters of SLS.

Masamitsu Aiba wrote his master’s thesis on particle accelerators 25 years ago. He later worked at CERN, and in 2009 he came to PSI. Now his specialty is injecting the electrons into the ring. “We’re about to see if all the new components fit together as precisely as we planned and calculated beforehand.” Aiba was himself involved in these detailed calculations – preparations for the renovation began several years ago.

On Tuesday, 14 January, the team succeeds in introducing the electrons into the first part of the storage ring. The particles do not get very far at first; which isn’t the first goal anyway. “It would be useless if we sent the electrons to do a full round once, but it was a bad round,” Aiba explains. The particles are so fast that, when SLS is operating, they fly through the entire ring a million times every second – even the smallest disturbance is noticeable. Actually storing the electrons in the ring only works if the first and therefore all subsequent rounds are as perfect as possible.

On his screens, Aiba can see exactly when the beam is not advancing well enough, and which magnet then needs to be adjusted and how. “Then we switch the machine off and confer with the people from the metrology group. They go into the accelerator tunnel and correct the magnets.” This part of the process is completely analogue, as screwdrivers are used to fine-tune individual permanent magnets until they are even better adjusted.

These new high-performance magnets are a crucial part of project SLS 2.0: the total number of magnets has been significantly increased; but where previously only electromagnets were installed, a large number of permanent magnets are now also in use. This makes the SLS a facility that is unique in the world and saves 60 percent energy compared to before. In addition, the permanent magnets reduce the noise that can affect the electron beam. All in all, the upgrade makes the electron beam 40 times better than before.

From a quarter of a lap to a million

On Wednesday, 15 January, the electrons are making it through the first quarter of the ring. One of the software windows on the second screen from the right displays a graphic with a row of 130 green dots, like pearls on a string. They show the measured values of the so-called beam position monitors, which register the position and intensity of the electron beam along the ring. The first 30 or so points have moved up, while all those behind them are still on the zero line – indicating how far the beam is getting so far. To make it farther, a few technical adjustments are now required.

Read more on PSI website

Image: Jonas Kallestrup, Masamitsu Aiba, and Felix Armborst (from left) in the PSI control room. They are part of the commissioning team that has now brought electrons back into the electron storage ring of the synchrotron as part of the SLS 2.0 upgrade project.

Credit: Paul Scherrer Institute PSI/Markus Fischer

A new dimension of complexity for layered magnetic materials

A new dimension of complexity for layered magnetic materials

When it comes to layered quantum materials, current understanding only scratches the surface; so demonstrates a new study from the Paul Scherrer Institute PSI. Using advanced X-ray spectroscopy at the Swiss Light Source SLS, researchers uncovered magnetic phenomena driven by unexpected interactions between the layers of a kagome ferromagnet made from iron and tin. This discovery challenges assumptions about layered alloys of common metals, providing a starting point for developing new magnetoelectric devices and rare-earth-free motors. 

Patterns are everything. With quantum materials, it’s not just what they’re made of but how their atoms or molecules are organised that gives rise to the exotic properties that excite researchers with their promise for future technologies. 

Graphene showed this to the world: arranged into single layers of a hexagonal lattice, common-or-garden carbon atoms could exhibit extraordinary electronic properties. Research over the last decade has since been dedicated to discovering whether other two-dimensional arrays of atoms, either alone or stacked into a three-dimensional material, can reveal similarly novel behaviours.

The kagome lattice, which takes its name from a type of Japanese basket woven in corner sharing triangles, is another two-dimensional pattern that has excited researchers with its ability to host exotic quantum states, ranging from superconductivity to unconventional magnetism. 

Yet until now, research has focused on electronic and magnetic properties in two-dimensions of the material. The latest results in Fe3Sn2 – a ferromagnetic material made of iron and tin atoms arranged into the intricate kagome pattern – change that.

Read more on the PSI website

Image: The kagome ferromagnet, Fe3Sn2 hosts spin waves – magnetic ripples arising from collective excitations of electron spins (shown here as golden arrows). The new findings reveal that the spin-waves are influenced by unexpected interactions between the layers in the material.

Credit: ©Wenliang Zhang / Paul Scherrer Institute PSI

New protective coating can improve battery performance

New protective coating can improve battery performance

A research team at the Paul Scherrer Institute PSI has developed a new sustainable process that can be used to improve the electrochemical performance of lithium-ion batteries. Initial tests of high-voltage batteries modified in this way have been successful. This method could be used to make lithium-ion batteries, for example those for electric vehicles, significantly more efficient.

Lithium-ion batteries are considered a key technology for decarbonisation. Therefore, researchers around the world are working to continuously improve their performance, for example by increasing their energy density. “One way to achieve this is to increase the operating voltage,” says Mario El Kazzi from the Center for Energy and Environmental Sciences at Paul Scherrer Institute PSI. “If the voltage increases, the energy density also increases.”

However, there is a problem: At operating voltages above 4.3 volts, strong chemical and electrochemical degradation processes take place at the transition between the cathode, the positive pole, and the electrolyte, the conductive medium. The surface of the cathode materials gets severely damaged by the release of oxygen, dissolution of transition metals, and structural reconstruction – which in turn results in a continuous increase in cell resistance and a decrease in capacity. This is why commercial battery cells, such as those used in electric cars, have so far only run at a maximum of 4.3 volts.

To solve this problem, El Kazzi and his team have developed a new method to stabilise the surface of the cathode by coating it with a thin, uniform protective layer. The researchers report on their discovery in a study published in the scientific journal ChemSusChem (Wiley).

Read more on PSI website

Image: Mario El Kazzi and his team have developed a cathode surface coating that enables operating voltages of up to 4.8 volts.

Credit: Paul Scherrer Institute PSI/Mahir Dzambegovic