CERN Accelerating science

Advancing superconductivity for future magnets

Superconductivity has been instrumental for the realization of large particle accelerators and is a key enabling technology for a future circular proton-proton collider (FCC-hh) reaching energies of 100 TeV.

The alloy Nb-Ti is undoubtedly the most successful practical superconductor, and it has been used in all superconducting particle accelerators and detectors built to date, but the higher magnetic fields required for the High Luminosity LHC (HL-LHC) upgrade and a future circular collider (FCC) call for new materials. An enabling superconducting technology for accelerator magnets beyond 10 tesla is the niobium-tin (Nb3Sn) compound.

Nb3Sn wires suitable for producing the 11 T magnets required for the HL-LHC have been produced in industry, but the high-field magnets proposed for the FCC would require a substantial step forward in performance. In order to achieve this goal, a conductor development programme is under way at CERN.

To address the challenges of this project, a Conductor Development Workshop has bene launched by CERN. Amalia Ballarino, leader of the Superconductor and Superconducting Devices (SCD) section says: “It is the right time to create momentum for the FCC study and to bring together the current participants in our conductor development project to share recent progress and discuss future activities.”

The focus of the conductor development programme is on the development of Nb3Sn multi-filamentary wires able to meet the target non-copper critical current density (Jc) performance of 1,500 A/mm2 at 16 T and at a temperature of 4.2 K (-268.95 °C). CERN is engaged in collaborative conductor development activities with a number of industrial and academic partners to achieve these challenging goals, and the initial phase of the programme will last four years.

Presently, the conductor developed for HL-LHC reaches a performance of about 1,000–1200 A/mm2 at 16 T and 4.2 K, and a significant R&D effort is needed to increase this by 30 to 50% to meet the requirements of 16 T magnets. “The magnets for future higher energy accelerators require fundamental research on superconductors to achieve the targets in performance and cost,” says Ballarino. For the FCC magnets, thousands of tonnes of superconductor will be required. Along with an increase in performance, a more competitive cost is needed, which calls for a wire design suitable for industrial-scale production at a considerably lower cost than the state-of-the-art conductor.

Representatives from five research institutes and seven companies, from the US, Japan, Korea, Russia, China and Europe, travelled to CERN in March 2018 to attend the first Conductor Development Workshop. “Our aim is to open up a space where collaborators can discuss the current status and review different approaches to meet the target performance and cost. The meeting also serves as an invitation to potential new partners interested in joining this effort”. Two new companies attended the workshop to discuss their possible future involvement in the project, namely Luvata and Western Superconducting Technologies (WST).

The workshop started with a plenary session followed by closed meetings during which companies engaged in fruitful discussions.  “Presentations in the plenary session gave a valuable overview of progress and future directions,” observed Simon Hopkins, a CERN expert on superconductivity and scientific secretary of the workshop, “but we recognise the commercial sensitivity of some of these developments. It was essential to provide an environment in which our industrial partners were free to discuss the details openly: both their proposed technical solutions and a realistic assessment of the challenges ahead.”

First Future Circular Collider conductor development workshop (Credit: Athina Papageorgiou-Koufidou).

The early involvement of industry, and their investment in developing new technologies, is crucial for the success of the programme. One of the positive outcomes of this meeting has been that, according to Amalia Ballarino: “Thanks to their commitment to the programme, and with CERN’s support, companies are now investing in a transition to internal tin processes. It was impressive to see achievements after only one year of activity”. Several partners have produced wire with Jc performance close to or exceeding the HL-LHC specification, and all of the companies that attended the workshop had new designs to present, some of which are very innovative.

Cross-sections of prototype Nb3Sn wires developed in collaboration with CERN as part of the FCC conductor development programme.Top: optical micrographs of wires from Kiswire Advanced Technology. Bottom: electron micrographs showing a wire developed by JASTEC in collaboration with KEK. Both show the unreacted wire before the heat treatment to form the Nb3Sn compound from the niobium filaments and tin. (Credit: KAT/JASTEC. The image originally appeared in the CERN Courier, June, 2018). 

The companies already producing Nb3Sn superconducting wire for the programme are Kiswire Advanced Technology Co., Ltd. (KAT); TVEL Fuel Company supported by the Bochvar Institute (JSC VNIINM); and from Japan, Furukawa Electric Co. Ltd. and Japan Superconductor Technology Inc. (JASTEC), coordinated by the Japanese High Energy Accelerator Research Organisation, KEK. Columbus Superconductor SpA will participate in the programme for other superconducting materials.  Arrangements are now being finalised for Luvata and another manufacturer, Bruker EAS, to join the programme; and the participation of our Russian partner, TVEL, has been renewed.

Moreover, the organizers acknowledged the contribution of the academic partners, who are developing innovative approaches for the characterization of superconducting wires, as well as investigating new materials and processes that could help meet the required targets. Developments include the correlation of microstructures, compositional variations and superconducting properties in TU Wien; research into promising internal oxidation routes in the University of Geneva; the study of phase transformations at TU Bergakademie Freiberg; and conductors based on novel superconductors at CNR-SPIN.

Finally, during the two-day workshop a panel of experts reviewed the conductor programme and offered their invaluable insights during the last session of the workshop. Their recommendations centred on the scope and focus of the programme, encouraging an emphasis on novel approaches to achieve a breakthrough in performance, with the broadest possible participation of industrial partners, underpinned by close long-term partnerships with research institutions. “We fully share the panel’s ambition for developing novel approaches with our industrial partners,” agreed Hopkins. “Improving our understanding of the materials science of Nb3Sn wires is also essential for developing new and optimised processing methods, and we welcome the contribution of new research institutes”. A US research institute, the Applied Superconductivity Center based in the National High Magnetic Field Laboratory (Florida State University) has also joined the programme.


The structure of the FCC Conductor Development Programme, showing the activities (shaded boxes) and partners. A dotted outline and italic text indicate pending participants, whose participation is currently being finalised. (Credit: CERN)

Since the workshop, partners in the conductor development programme have continued to make good progress: the latest results will be presented at the Applied Superconductivity Conference in October 2018 (Seattle, USA), and a second edition of the workshop is planned in 2019.

We are confident that this will result in a new class of high-performance Nb3Sn material suitable not only for accelerator magnets, but also for other large-scale applications such as high field NMR and laboratory solenoids or MRI scanners for medical research.


Top image:  High-performance Nb3Sn cables are being assembled by a Rutherford cabling machine in CERN's superconducting laboratory (Credits: CERN). 

Romain Muller (CERN)
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Science transcends boundaries

For a third year, the European Union (EU) Delegation to Japan, together with EU Member State embassies, European and Japanese research laboratories organized a number of events during the Science Agora 2017, Japan’s largest science fair. Every year, Science Agora offers a unique opportunity for scientists to interact with policymakers and the general public to discuss how science and technology transform our daily lives and occupy a central place in economic growth and societal change.

The key theme of the 2017 Science Agora was “Beyond the Boundaries”. In this regard, international collaboration and geographical diversity are just as important as diversity of disciplines. The FCC study, supported through EC’s H2020 EuroCirCol programme, was presented as an example of how international scientific collaboration transcends different boundaries and could help us address a number of inter-connected global challenges. In total five projects were selected to showcase how collaboration between European and Japanese institutes boosts frontiers in particle physics, sustainable energy sources, the internet of things, nuclear fusion, smart cities and climate change.

EU's "participation in Science Agora is thus driven by our twofold desire to show in a tangible manner some of the best science and innovation which are being developed in Europe, and to demonstrate the diverse ways in which European and Japanese researchers and scientists are cooperating", said EU Ambassador Viorel Isticioaia-Budura.

The opening ceremony of EU's participation to Science Agora 2017 in Tokyo. EU Ambassador to Japan Viorel Isticioaia-Budura (right) and Leonidas Karapiperis, Head of S&T Section, Delegation of the EU to Japan (left) (Image Credits: EU delegation to Japan).

Frank Zimmermann (Deputy FCC-study leader) discussed how the FCC study strengthens the role of global collaboration in science, technology and innovation, leveraging the competencies of experts from different fields and countries. “We are facing a changing reality that not only opens up the opportunity for collaboration, but which actually necessitates the latter, as it becomes increasingly difficult for individual scientists or even individual countries to conduct groundbreaking research on their own. We have witnessed how scientific research has evolved over the past decades, requiring R&D efforts beyond institutes and even countries to develop novel enabling technologies.” International cutting-edge research helps us cross the boundary between the present and the future, and allows us to envisage a much more powerful post-LHC collider.

Moreover, Zimmermann presented the joint efforts with KEK and University of Tokyo in developing a new generation of superconductors that will meet the requirements of the high-field magnets needed for a 100 TeV energy frontier collider. It is key to the success of any high-tech project to involve the entire scientific and engineering community from the very early days onwards.

Frank Zimmermann (CERN) presenting the scope of the study for a Future Circular Collider and highlighting aspects of the collaboration with Japanese research institutes and universities.

The European Union’s participation in the Science Agora also included lively demonstrations of superconductors, a video illustration of the FCC collider, poster presentations, and small tokens for the young visitors! This event offered the opportunity for European and Japanese researchers to present their joint projects and, conversely, to listen to the voices of the general public, including Japanese high-school, middle-school and primary-school students fascinated by science. This next generation will eventually provide the researchers to work on the proposed future accelerator complex. At the Agora, the participating scientists also shared their original motivation and the questions they are trying to address through their research, thereby inspiring many young students who were curious about a researcher’s life.

The stand of the EU delegation in the Science Agora 2017 giving information about a number of EC supported projects.

The FCC study along with the other collaborative projects that were presented at the Science Agora 2017 are helping to expand the area of world-leading scientific and technological collaboration between Japan and Europe – an area that will create growth and that will offer to young people, from around the world, the space to dream, to aspire and to develop.

Cristian Pira, Oscar Azzolini, Giorgio Keppel, Silvia Martin, Fabrizio Stivanello
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Physics of Star Wars: Science or Fiction?

Light sabres, hyper speed and droids – how do they all connect with the latest accelerator research? With the imminent launch of “The Last Jedi”, Professor Carsten Welsch, Head of Physics at the University of Liverpool and Head of Communication for the Cockcroft Institute, has explored the “Physics of Star Wars” in an event on 27th November designed to introduce cutting-edge accelerator science to hundreds of secondary school children, undergraduate and PhD students, as well as university staff.

The day started with a lecture which first presented iconic scenes from the movies to then explain what is possible with current technology and what remains fiction. For example, a lightsabre, as shown in the film, wouldn’t be possible according to the laws of physics, but there are many exciting applications using lasers. There is a link to advances in lasers and laser acceleration being studied by an international collaboration within the EuPRAXIA project. This programme is developing the world’s first plasma accelerator with industry beam quality. It uses a high intensity laser pulse to drive an electron beam and accelerate this to high energies. Applications in science or industry that are close to a light sabre include for example 3D printing of metals and laser cutting.

Professor Welsch said: “In the very first movie from 1977, the rebels have used proton torpedoes that make the Death Star explode as their lasers wouldn’t penetrate the shields. I linked that to our use of ‘proton torpedoes’ in cancer therapy. Within the pan-European OMA project we are using proton beams to target something that is hidden very deep inside the body and very difficult to target and destroy.”

 OMA Fellow Jacinta Yab explaining the use of ‘proton torpedoes’ in cancer therapy (Image credit: QUASAR Group)

 The light and dark side of the Force in Star Wars was an ideal opportunity to talk about matter and antimatter interactions which are currently being explored at CERN’s AD and ELENA storage rings, as well as within the brand-new Marie Sklodowska-Curie research network AVA. Finally, participants learned about how high energy colliders, such as the LHC, its high luminosity upgrade or a potential Future Circular Collider (FCC) as it is being studied within the EuroCirCol project, can provide fantastic opportunities to study the force(s).

High school students participating in hands-on activities during ‘Physics of Star Wars’ event. (Image credit: QUASAR Group)

After the lecture, all participants were given the opportunity to understand the science behind Star Wars through numerous hands-on activities in the university’s award-winning Central Teaching Laboratory. This included laser graffiti, augmented reality experiments with Star Wars droids and virtual accelerators using AcceleratAR, and even two full-scale planetariums which fully immersed participants into the world of Star Wars, deflecting charged particle beams using Helmholtz coils.

Professor Welsch and members of his QUASAR Group had the kind permission of Lucasfilm to use film excerpts; these were complemented by Lego Star Wars models, a real cantina as found in the movies, storm troopers and even Darth Vader himself! Many photographs from the exciting day can be found on Twitter at

Lucasfilm had no involvement in the preparation or delivery of the event which was organised only by staff and students from the University of Liverpool.


Header image: Prof Carsten Welsch presenting the ‘Physics of Star Wars’ (Image credit: QUASAR Group)

Panagiotis Charitos (CERN)
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European and Japanese collaboration in the framework of the FCC study was highlighted during Science Agora 2017

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