CERN Accelerating science

HL-LHC equipment installed on both sides of the ALICE experiment

Installation of a bypass cryostat at LHC Point 2, where the ALICE experiment is located. These new bypass cryostats have been designed to host a collimator (Image: CERN)

The upgrades performed during Long Shutdown 2 (LS2) will allow the ALICE experiment to operate at higher luminosities than before, starting from the next run of the LHC. A higher luminosity means a higher number of collisions in the detector every instant. Yet, during heavy-ion collisions, which is the speciality of the ALICE experiment, a wider variety of particles are generated than in proton collisions. And some of these particles escape from the detector and fly alongside the beam trajectory. Two additional collimators must therefore be installed around the experiment, one for each exiting beam, to remove the particles deviating from the beam trajectory before they can reach the superconducting magnets. Indeed, particles hitting a magnet cooled down at 1.9 K (-271°C) cause it to heat up, resulting in a loss of its superconducting state.

To host these collimators, two innovative cryostat units have been inserted along the continuous cryostats of the LHC, on both sides of LHC Point 2, where the ALICE experiment is located. These units allow a collimator that has to operate at room temperature to be inserted along the beam lines, while still ensuring continuity of all the other lines of the magnets system: that is why they are called bypass cryostats. This upgrade is part of the High-Luminosity LHC (HL-LHC) project, whose first components have already been put in place in the LHC tunnel during the first part of LS2.

“These new bypass cryostats have been designed to host a TCLD (Target Collimator Long Dispersion suppressor) collimator, while connecting two adjacent cryostats to ensure the continuity of the vacuum, the cryogenic lines and the superconducting electrical cables,” explains Délio Ramos of the TE department, project engineer responsible for the magnet cryostats. The same type of bypass units will be used around LHC Point 7 for the installation of two TCLD collimators: in this case, they will be housed between two new 11-Tesla superconducting dipole magnets, which are among the most innovative equipment to be installed for HL-LHC during LS2.

At the beginning of the year, both the bypass cryostat units have been installed and interconnected and the first collimator has been installed on one side of ALICE; the second one will take up residence later this year. These collimators, which were developed alongside the new bypass cryostats, are much more compact than standard collimators. Nonetheless, a pre-existing 13-metre-long LHC cryostat unit, a so called connection cryostat as it ensures continuity between adjacent magnets, had to be replaced by two new ones, of a new design. These new connection cryostats are shorter (around 5 m long each) so that they can be placed, with the bypass cryostat in between, within the original 13-metre allocated slot.

LHC,High-Luminosity LHC,connection,cryostats,bypass,cmi
This new connection cryostat is around 5 m long. It has been designed to be connected to a bypass cryostat (Image: CERN)

Like every connection cryostat, these new short connection cryostats ensure the continuity of electrical powering, cooling and vacuum in the magnet system, though they do not contain magnets. “As for the previous connection cryostats, the new short ones also have to ensure a beamline support and alignment which guarantee a positioning accuracy of within 0.5 mm over the cryostat’s length,” explains Arnaud Vande Craen, the TE department’s engineer-in-charge of connection cryostats. “We had to develop a smaller version of these connection cryostats fitted with an interface that is compatible with the bypass.” The new short connection cryostats have been developed and manufactured in three years.

This project has been carried out thanks to collaboration between various teams in the Accelerators and Technology sector, which comprises the BE, EN and TE departments.

Originally published on

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EASISchool Grenoble

Cryogenics and its applications took central stage during the EASISchool 2 that was held from the 30th of September to the 4th of October in two CEA sites, Paris-Saclay and Grenoble, France. Advancements in cryogenic technology has handed scientists and engineers the unique tools paving new ways in our study of the Universe but also finding applications that have revolutionized our way of living. Today, cryogenics finds its application in almost all modern accelerators for research in particle physics and in a broad range of domains including medical instruments, rocket and satellite science, electronics,  manufacturing and food industry among others.

EASISchool 2 offered an intensive training program for the early-stage career researchers, following last year’s EASITrain’s summer school on superconductivity. The school provided training at doctoral level for about 40 students and researchers from all over the world. This is what really happened during the EASISchool autumn school. The scientific and technical topics of the school were selected to give the students the capacity to use, develop, and design the cryogenic instruments, needed for both research and industrial applications. The school focused on open R&D topics that offer the opportunity for collaboration between the academia and the industry while offering to EASITrain early-stage researchers a broad exposure to several companies.

The first day was devoted to cryogenics in the medical instruments, Magnetic Resonance Imaging (MRI) and proton-therapy, and to accelerator applications with presentations from experts on the challenges for superconducting magnets, and RF cavities. Speakers from CEA-Saclay, Varian Medical Systems, ZANON, Institut de Physique Nucléaire d’Orsay, and Research Instruments presented a broad spectrum of applications and lessons learned in the field. The importance of cryogenics for superconducting magnets not limited to particle physics was in the main focus during the second day. The increase of energy in accelerators over the past decades has led to challenging design of superconducting magnets for both accelerators and the associated detectors with LHC pushing accelerator magnet technology to its limits Superconducting magnets are under construction for the International Thermonuclear Experimental Reactor Programme (ITER) built in Cadarache, France. In both cases cryogenics is essential to reach the desired operating temperatures and maximize the performance of these machines. Moreover, ongoing R&D on high-temperature superconductivity, pulsating heat pipe, LNG transport (Gaztransport & Technigaz), and levitation were discussed. Finally, more innovative applications of cryogenics; from quantum computation (Oxford Instruments) to deep-space missions were covered on the afternoon of the second day. The visits of the world-largest MRI magnet (11.7T) at the Neuro-science laboratory and of the accelerator and cryo-magnetism laboratories at CEA-Saclay perfectly illustrated the school lectures.

The world-largest MRI magnet in its final location at the Neurospin laboratory, CEA Paris-Saclay

In the following days in Grenoble, EASISchool 2 took a deeper look into the space and aerospace applications of cryogenics with presentations from ESA, CEA-Grenoble, CNRS, Absolut System, and Air Liquide on different technologies developed to tackle the specific challenges of the space missions. The Planck mission that offered in 2013 the most precise map of the Cosmic Microwave Background radiation, and the MeteoSat satellite were two of the examples discussed during the sessions. The discussion continued in the afternoon with presentations from Air Liquide, Thales Alenia Space, and Ariane Group. Finally, the school covered large-scale cryogenic refrigeration and liquefaction domains, and finished with an inspiring talk on the management of research and innovation at Air Liquide.


EASISchool 2 participants at the top of the beautiful site of the Bastille summit, Grenoble.

During the school in Grenoble, participants also had a unique chance to visit Air Liquide Advanced Technologies headquarters and take a guided tour in the space application clean room, the turbo-expanders test facility and the large helium liquefier/refrigerator/cryolines construction workshop. Moreover, participants had a chance to visit the Cryogenic Laboratories of CEA-Grenoble, France’s National High Magnetic Field laboratory and the European Synchrotron Radiation Facility in Grenoble, learning about the diverse research programs in condensed and living matter using the world's most intense X-ray source.


Visit to the turbo-expander test bench at Air Liquide Advanced Technologies factory

EASISchool 2 also featured satellite public events including the opening of the public travelling exhibition “The Code of the Universe”, installed for three months at the MINATEC site at Grenoble, France. The photographic exhibition opened on the 18th of September followed by a public lecture of the FCC-ee co-leader, Prof. Alain Blondel (University of Geneva) who discussed the challenges of designing the Future Circular Collider as humanity’s next adventure. The exhibition was also part of the “Grenoble Fête de la Science 2019” giving the opportunity to thousands of visitors to visit it and learn more about the technologies needed to progress in fundamental physics. Moreover, Jakub Tkaczuk, a MSCA EASITrain fellow working in CEA-Grenoble, offered guided visits for local primary and high schools. A public conference “La cryogénie au service des découvertes scientifiques” (Cryogenics for scientific discoveries) concluded this EASITrain animation at the “Grenoble Fête de la Science 2019”.


EASITrain animation around the exhibition “The Code of the Universe” at the French “Fête de la Science 2019”on the 10th and 12th of October 2019 at MINATEC, Grenoble. Jakub Tkaczuk (MSCA Early Stage Researcher) initiated more than 400 students from primary and high schools to discover the superconducting and cryogenic applications.

The scientific and social program of the school offered valuable insights into novel approaches in cryogenics, and valuable networking with experts from different fields. Constructive discussions during the school proved that challenges become manageable from different angles and creative solutions sometimes emerge. Stay tuned for the next EASISchool that will take place in September 2020 in Genova, Italy.


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EASIschool '18: A summer to remember

Visiting new places, learning amazing things, experiencing different cultures and meeting interesting people from around the world: these are perhaps the right ingredients for a great summer. It’s also how one would summarize the first EASIschool that took place this summer in Vienna.

From the 30th of August to 14th of September, the MSCA H2020 EASITrain programme brought together young researchers for an intensive summer meeting! It was the culmination of the first year's activities, bringing students together from different research centres and industries for a shared experience in Vienna. The school encompassed a wide variety of engaging academic disciplines and outdoor activities.

With a comprehensive curriculum developed in coordination with all beneficiaries,, the first week offered to students the knowledge and resources to understand the inner workings of superconductivity. World-class experts covered a wide range of topics from the fundamental of superconductivity to novel characterization and manufacturing techniques, developments in high-temperature superconducting materials and possible applications outside particle physics. Students got a deep theoretical understanding and at the same time were invited to think of ways to deploy large-scale applications. Industrializing these technologies is key for future large-scale research infrastructures and could unlock their transformative potential for society.

Participants of the first EASIschool after their visit to MedAustron where they learned more about the applications that superconductivity can have outside HEP (Credit: Mattia Ortino). 

The second week of the school focused on a project management training as young researchers should learn how to skillfully coordinate and manage future projects. Managing the interaction between different stakeholder groups, ensuring adequate financing and resources and conceiving a realistic timeplan along with a detailed risk analysis are among the key factors for the success of a project. Experts from TU Wien, CERN and the Economic University of Vienna discussed these aspects and offered a hand-on training to the students. In addition, during an intense one-day media training, students learned about the key concepts and methodologies of storytelling; narrating their personal stories and motivation to join EASITrain turned out to be a moving experience that brought them closer and strengthen the team spirit of EASITrainers!

After the one-day media training in Terra Matter Factual Studios (Credit: © Terra Mater Factual Studios/Florian Wieser)

EASISchool also offered a rich and diverse social programme that included a visit to the Atominstitut and MedAustron; an ion-therapy centre that exemplifies the knowledge transfer from CERN to its member states. The highlight was a public discussion on the 8th of September with the student’s participation on “Forschung? Was geht mich das an!” an event co-organized with HEPHY, the Austrian Academy of Sciences and Vienna’s Natural History museum (

Alice Moros and Mattias Ortino, two of the MSCA EASITrain ERCs in front of the World Wide Würstelstand with Rolf Heuer during the public event “Research: What is there for me”? (Credit: Bill Lorenz)

Group photo before the public event that was jointly organized by CERN, EuroCirCol and EASITrain H2020 programmes, NHM and OAW/HEPHY. From left to right: Dr. Michael Benedikt (CERN, FCC study project leader), Olivera Böhm (Head of UNIQA Group Corporate Business), Christian Köberl (Generaldirektor Naturhistorisches Museum Wien), Georg Bednorz (Nobelpreis Physik 1987). Reinhold Mitterlehner (Wissenschaftsminister a.D., Präsident der ÖFG), Birgit Denk (Moderator), Alice Moros (EASITrain researcher), Wolfang Burtcher (Deputy Director, EC DG Research and Innovation), Gregor Weihs (Univ.-Prof., Vizepräsident des FWF) and Johannes Gutleber (CERN, Head FCC study office).

Speakers included among others, Nobel Prize Winner on high-temperature superconductivity “Georg Bednorz” and CERN’s former Director General “Rolf Heuer” and Alice Moros one of the ERCs. The event coincided with the opening of the travelling photographic exhibition “CODE of the Universe” in front of the NHM as part of the “Be OPEN: Science and Society” festival in Vienna.

The travelling photographic exhibition "Code of the Universe" opened in front of Vienna's Natural History Museum. 

Looking back, the first EASISchool was a big success! It offered an outstandingly diverse programme covering: the scientific foundations of superconductors, economic and technological aspects of innovation and a number of outreach and communication activities to explain the benefits of fundamental research to a wider audience. Participants learned from the experiences of their peers, absorbed the knowledge their tutors had to offer and made new long-standing friends broadening their networks! Could you think of a better way to spend your summer?


Watch a trailer of the webcast of this event: 


You can find the detailed programme of EASISchool:

More information about the photographic exhibition “CODE of the Universe”:
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