CERN Accelerating science

Fermilab achieves 14.5-tesla field for accelerator magnet, setting new world record

A member of the Fermilab magnet team prepares the demonstrator accelerator magnet for testing in March 2020. These tests are an important step toward meeting the requirements of a future hadron collider under discussion in the particle physics community. Photo: Alexander Zlobin

In a June 2020 test, a demonstrator magnet designed and built by the magnet team at the Department of Energy’s Fermilab achieved a 14.5-tesla field strength for an accelerator steering dipole magnet, surpassing their previous record of 14.1 T.

This test is an important step toward addressing the demanding magnet requirements of a future hadron collider under discussion in the particle physics community. If built, such a collider would be four times larger and almost eight times more powerful than the 17-mile-circumference Large Hadron Collider at the European laboratory CERN, which operates at a steering field of 7.8 T. Current future-collider designs estimate the field strength for a steering magnet — the magnet responsible for bending particle beams around a curve — to be up to 16 T.

“Our next goal is to break the ’15-tesla wall’ and advance the maximum field in accelerator steering magnets to 17 T and even above, significantly improve magnet quench performance and optimize cost,” said Fermilab scientist Alexander Zlobin, who leads the magnet project. “Reaching these goals will provide strong foundation for future high-energy colliders.”

Read more about the Fermilab-built future-collider steering magnet.

Originally published by Fermilab.

Daniela Antonio (CERN)
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Demonstrator racetrack dipole magnet produces record peak field

The enhanced Racetrack Model Coil (eRMC) is a magnet consisting of two racetrack (block) coils assembled without midplane gap and featuring a straight section of approximately 750 mm allowing the study of the design and assembly parameters relevant for full-length accelerator magnets. The magnet produced a 16.36 T central field at 1.9 K and a 16.5 T peak field on the coil. This is the highest dipole field ever reached for a magnet of this configuration. The magnet was also tested at 4.5 K and reached a field of 16.3T, corresponding to 98% of the estimated conductor limit at this temperature as measured from witness strands.

The enhanced Racetrack Model Coil (eRMC). (Image: CERN)

The magnet uses Nb3Sn superconducting wires, the superconductor used for the High Luminosity LHC Project (HL-LHC). The same material (Nb3Sn) in an identical cable configuration, was used for FRESCA2, a 100 mm aperture dipole magnet also built with block coils, to be installed in a test facility at CERN. In 2018, FRESCA2 has set a world record field for a bore-free dipole magnet of 14.6 T.

It is worth recalling the result recently achieved with the MDPCT1 magnet at FNAL by the US-MDP (Magnet development Program), a US-DOE program with objectives comparable to the FCC Project Study. MDPCT1, with an aperture of 60 mm, was tested at FNAL in June 2019 and achieved 14.1 T at 4.5K, a world record for a cos-theta model magnet (see previously on Accelerating News).

These results, and the recent advances on Nb3Sn conductors, demonstrate the potential of this technology for a next step hadron collider such as the FCC-hh. In the past year, the FCC 16T magnet development programme has attracted global interest, supported also by the EU-funded EuroCirCol project, allowing to establish a rigorous collaboration to carry on further R&D on the domains of superconducting technologies and mechanical design (see also “Towards 16T magnets for future particle colliders”).

After the success of this test, the next step is to dis-assemble eRMC, and re-assemble it adding an additional racetrack coil in the midplane, opening a cavity of 50 mm diameter. This configuration will reproduce, in its central part, the same coil geometry as that of an accelerator dipole magnet built with block coils. 

Ricardo Torres (University of Liverpool)
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Fermilab achieves 14.5-tesla field for accelerator magnet, setting new world record
15 Jul 2020

Fermilab achieves 14.5-tesla field for accelerator magnet, setting new world record

Fermilab achieved a 14.5-tesla field strength for an accelerator steering dipole magnet, surpassing their previous record of 14.1 T.

HL-LHC superconducting quadrupole successfully tested

The quadrupole magnet being prepared for a test at Brookhaven National Laboratory. (Image: Brookhaven National Laboratory)

 

A quadrupole magnet for the high-luminosity LHC (HL-LHC) has been tested successfully in the US, attaining a conductor peak field of 11.4 T – a record for a focusing magnet ready for installation in an accelerator. The 4.2 m-long, 150-mm-single-aperture device is based on the superconductor niobium tin (Nb3Sn) and is one of several quadrupoles being built by US labs and CERN for the HL-LHC, where they will squeeze the proton beams more tightly within the ATLAS and CMS experiments to produce a higher luminosity. The result follows successful tests carried out last year at CERN of the first accelerator-ready Nb3Sn dipole magnet, and both of these milestones are soon to be followed by tests of other 7.2 m and 4.2 m quadrupole magnets at CERN and the US.

“This copious harvest comes after significant recent R&D on niobium-tin superconducting magnet technology and is the best answer to the question if HL-LHC is on time: it is,” says HL-LHC project leader Lucio Rossi of CERN. “We should also underline that this full-length, accelerator-ready magnet performance record is a real textbook case for international collaboration in the accelerator domain: since the very beginning the three US labs and CERN teamed up and managed to have a common and very synergic R&D, particularly for the quadrupole magnet that is the cornerstone of the upgrade. This has resulted in substantial savings and improved output.”

The current LHC magnets, which have been tested to a bore field of 8.3 T and are currently operated at 7.7 T at 1.9 K for 6.5 TeV operation, are made from the superconductor niobium-titanium (Nb-Ti). As the transport properties of Nb-Ti are limited for fields beyond 10-11 T at 1.9 K, HL-LHC magnets call for a move to Nb3Sn, which remain superconducting for much higher fields. Although Nb3Sn has been studied for decades and is already in widespread use in solenoids for NMR — not to mention underpinning the large coils, presently being manufactured, that will be used to contain and control the plasma in the ITER fusion experiment – it is more challenging than Nb-Ti to work with: once formed, the Nb3Sn compound becomes brittle and strain sensitive and therefore much harder than niobium-titanium alloy to process into cables to be wound with the accuracy required to achieve the performance and field quality of state-of-the-art accelerator magnets.

Researchers at Fermilab, Brookhaven National Laboratory and Lawrence Berkeley National Laboratory are to provide a total of 16 quadrupole magnets for the interactions regions of the HL-LHC, which is due to operate from 2027. The purpose of a quadrupole magnet is to produce a field gradient in the radial direction with respect to the beam, allowing charged-particle beams to be focused. A test was carried out at Brookhaven in January, when the team operated the 8-tonne quadrupole magnet continuously at a nominal field gradient of around 130 T/m and a temperature of 1.9 K for five hours. Eight longer quadrupole magnets (each providing an equivalent “cold mass” as two US quadrupole magnets) are being produced by CERN.

“We’ve demonstrated that this first quadrupole magnet behaves successfully and according to design, based on the multiyear development effort made possible by DOE investments in this new technology,” said Fermilab’s Giorgio Apollinari, head of the US Accelerator Upgrade Project in a Fermilab press release. “It’s a very cutting-edge magnet,” added Kathleen Amm, who is Brookhaven’s representative for the project.

Dipole tests at CERN

In addition to stronger focusing magnets, the HL-LHC requires new dipole magnets positioned on either side of a collimator to correct off-momentum protons in the high-intensity beam. To gain the required space in the magnetic lattice, Nb3Sn dipole magnets of shorter length and higher field than the current LHC dipole magnets are needed. In July 2019 the CERN magnet group successfully tested a full-length, 5.3-m, 60-mm-twin-aperture dipole magnet – the longest Nb3Sn magnet tested so far – and achieved a nominal bore field of 11.2 T at 1.9 K (corresponding to a conductor peak field of 11.8 T).

“This multi-year effort on Nb3Sn, which we are running together with the US, and our partner laboratories in Europe, is leading to a major breakthrough in accelerator magnet technology, from which CERN, and the whole particle physics community, will profit for the years to come,” says Luca Bottura, head of the CERN magnet group.

The dipole- and quadrupole-magnet milestones also send a positive signal about the viability of future hadron colliders beyond the LHC, which are expected to rely on Nb3Sn magnets with fields of up to 16 T. To this end, CERN and the US labs are achieving impressive results in the performance of Nb3Sn conductor in various demonstrator magnets. In February, the CERN magnet group produced a record field of 16.36 T at 1.9 K (16.5 T conductor peak field) in the centre of a short “enhanced racetrack model coil” demonstrator, with no useful aperture, which was developed in the framework of the Future Circular Collider study. In June 2019, as part of the US Magnet Development Programme, a short “cos-theta” dipole magnet with an aperture of 60 mm reached a bore field of 14.1 T at 4.5 K at Fermilab. Beyond magnets, says Rossi, the HL-LHC is also breaking new ground in superconducting-RF crab cavities, advanced material collimators and 120 kA links based on novel MgB2 superconductors.

Next steps

Before they can constitute fully operational accelerator magnets which could be installed in the HL-LHC, both these quadrupole magnets and the dipole magnets must be connected in pairs (the longer CERN quadrupole magnets are single units). Each magnet in a pair has the same winding, and differs only in its mechanical interfaces and details of its electrical circuitry. Tests of the remaining halves of the quadrupole- and dipole-magnet pairs were scheduled to take place in the US and at CERN during the coming months, with the dipole magnet pairs to be installed in the LHC tunnel this year. Given the current global situation, this plan will have to be reviewed, which is now the high-priority discussion within the HL-LHC project.

This news appeared first at the CERN Courier

This news was also featured at Fermilab

Igor Syratchev (CERN)
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FCC Week 19: Towards 16T magnets for future particle colliders
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FCC Week 19: Towards 16T magnets for future particle colliders

In past decades, the development of high-field superconducting accelerator magnets received a boost from high-energy physics.

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FCC Week 19: Towards 16T magnets for future particle colliders

 

 

 

 

In the past decades, the development of high-field superconducting accelerator magnets received a strong boost from high-energy physics. The current state-of-the-art are the LHC dipole magnets operating in the LHC at around 8T. Exploring higher energies, up to 100 TeV, requires higher magnetic fields to steer the more energetic hadron beams at a future circular collider (FCC). The goal is to double the field strength compared to the LHC dipole magnets, reaching up to 16 Tesla. This goal can only be achieved with a different superconductor technology compared to the Nb-Ti used in LHC. Currently niobium tin (Nb3Sn) is explored as a viable candidate for reaching this goal. Other superconducting technologies, like High-Temperature Superconductors (HTS), MgB2 and iron-based materials, are also under study: REBCO tapes are being used in HTS development coils, whilst MgB2 and iron-based materials are under investigation as part of the FCC conductor development programme.

The first magnets using the Nb3Sn technology, the so-called 11T dipole magnets and the final focusing magnets are developed for HL-LHC. Designing, manufacturing and operating such high-field accelerator magnets is not a trivial task while it should be noted that the strength of the field is only one of the parameters that inform the design of accelerator magnets. In the case of FCC, more than 5000 dipole superconducting magnets will be needed for the 100 km tunnel. These magnets will have to be powered in series and operate continuously over long time periods. Therefore a reliable and efficient magnet design is key for the sustainable operation of this machine. 

The FCC study explores a number of critical aspects that underlie the design, cost-efficient manufacturing and reliable operation of 16T dipole magnets for future particle colliders. Among them is the improvement of the state-of-the-art Nb3Sn performance towards a target critical current density of 1500 A/mm2 at 16 T and 4.2 K, i.e almost a 50% increase compared to the HL-LHC specifications. Moreover, the industrialisation of such high-performing wire for large scale production and the achievement of a target cost for the Nb3Sn wire andurthermore, the design of cost-effective 16 T dipole magnets with adequate electromagnetic and structural designs as well as the improvement of magnet training.

To meet this goal, the FCC collaboration has launched a rigorous R&D conductor development programme and a R&D magnet programme. The conductor development programme focuses on the development of Nb3Sn wire with a target performance exceeding that of state of the art conductors. The world-wide community, including leading companies and laboratories from Europe, Korea, Japan and Russia, has enthusiastically taken on  the challenge. All collaborators have reached impressive achievements. Unit lengths of Nb3Sn wires with performance at least comparable to that of the HL-LHC conductor have been produced in industry and cabled at CERN. 

Very promising achievements reached in the USA with the production of R&D Nb3Sn wire via new technologies were presented during the FCC week 2019. At Fermilab, multi-filamentary wire produced with the Internal Oxidation process has already exceeded the FCC target critical current density – reaching values of up to about 1600 A/mm2 at 16 T and 4.2 K. Moreover, work at the Applied Superconductivity Centre of Florida State University has demonstrated the beneficial influence in improving the high-field performance of Nb3Sn via Hafnium addition to Nb-Ta.

In contribution to the FCC Conductor Development Programme, the Applied Superconductivity group at the University of Geneva has demonstrated that a combination of high upper critical field and enhanced critical current density can be obtained by grain refining in Ta-doped Nb3Sn with internally oxidised Zr. With a record-high value of 28.8 T at 4.2 K, the upper critical field of the samples based on Nb-Ta-Zr alloys even surpasses the values of industrial state-of-the art Nb3Sn conductors. Moreover, under the EuroCirCol conductor programme, the effect of the transverse load on the performance of Nb3Sn cables and wires was quantified following a successful collaboration with the Universities of Geneva and Twente. The effect becomes more relevant in higher fields and the results will inform the design of the final magnets.

“The enthusiasm of the world-wide superconductors’ community and the achievements are impressive”, says Amalia Ballarino, leader of the conductor activity at CERN. “The FCC conductor development targets are very challenging. The demonstration of the possibility of reaching the target critical current density in development Nb3Sn wires is a milestone in the history of Nb3Sn conductor and a reassuring achievement for the FCC magnet development programme”.     

The magnet programme includes three main activities covering the required R&D on superconducting cable, magnet cross section, iron yoke, collars and the magnet structure. Key components of the programme are CERN’s magnet development programme beyond HL-LHC  (which sets a milestone for the FCC high-field magnets), an ongoing R&D effort involving a network of academic institutes and industrial partners firmly supported by the EU-funded  Horizon 2020 EuroCirCol project, the FCC Conductor Development Programme and connection with other programmes taking place around the world, with first and foremost the US Magnet Development Programme as well as partners from Russia and Asia. These programmes have attracted partners, both from the academia and industry, who collaborate to tackle the complex challenges for the more powerful magnets needed for an energy-frontier collider. More innovative and better-integrated activities between academia and industry led to a cost optimised magnet design and the availability of different conductor options. The outcome of this joint effort is documented in the FCC Conceptual Design Report (CDR) and was extensively discussed during the 2019 FCC week. 

The FCC CDR included design and cost models for the magnets, based on the results of the EU supported EuroCirCol WP5. These showed that several different design options have the potential, to deliver 16 T in a reliable and cost-efficient way, once properly developed.

The efforts focused on the integration of the electromechanical characteristics of the conductor. Nb3Sn is a brittle material, which can crack easily, so specific care and attention are required  starting from the initial design phase on the electromechanical properties. The magnet design was treated as one integrated task including the structural, the magnetic and the magnet protection design. All collaborators used the same set of parameters for their simulations. Davide Tommasini (leader of the FCC magnet R&D) stresses that: “The impact of the programme in the relevant community has been extremely important. A considerable effort has been made, by all parties, in cultivating an environment in which information is openly shared throughout the whole duration of the programme”.

To this end, EuroCirCol WP5 has organised about 40 collaboration video-meetings and around 30 topical meetings, many of them with the enlarged participation of the US laboratories engaged in the US MDP. A number of national research laboratories including CEA (France), CIEMAT (Spain), INFN (Italy) and CHART (Switzerland) have recently signed agreements in the framework of the CERN FCC 16T programme with the aim of manufacturing around 1 m long prototypes of the designs developed within EuroCirCol, as a step towards building full scale models. The Swiss Chart-II roadmap for applied superconductivity is also planning significant contributions towards the high-field magnets required for FCC. CERN is coordinating these efforts through an international high-field magnet forum. Daniel Schoerling, the coordinator of the high-field magnet forum, states that ‘this forum shall continue providing a platform for the different institutes, as successfully cultivated during the EuroCirCol programme.’ 

An eRMC magnet structure was assembled at CERN using instrumented aluminium dummy coils and its mechanical structure has been characterised at cryogenic temperature. Moreover, three superconducting Nb3Sn coils are produced and ready for assembly for the first cold powering tests scheduled for the end of this year. 

Finally, the recent success of the test of the US MDP cosine-theta dipole, which achieved its target of 14T was announced during the FCC week 2019. Daniel Schoerling, coordinator of the International High-Field Magnet Forum, and some other key speakers highlighted in their talks the importance of the MDP 15 T dipole program and how the latest results that considerably strengthen the FCC Design Report.

Following this successful test, the magnet pre-stress will be increased in order to reach its design limit of 15 T. This result, obtained on a very early stage of a tailored R&D for high-field accelerator magnets, puts future closer in time. This project was initiated four years ago at Fermilab by Alexander Zlobin and the Fermilab Supeconducting Magnet team, in response to the P5 and HEPAP Accelerator R&D subpanel recommendations. In June 2016, after the Office of High Energy Physics at US-DOE created MDP to integrate accelerator magnet R&D in the United States and coordinate it with the international effort, this project became a key task of the MDP. A year later this effort received support also by the EuroCirCol program, making it a truly International endeavor. The next step of this project is to re-assemble the magnet with higher coil pre-load to achieve its design goal of 15 T.

Fig 1.  15 T dipole demonstrator MDPCT1 with project leader A.V. Zlobin and 15 T project team (Fermilab).

In addition to the baseline design of the cosine-theta coil type, other design options have been studied in detail and will be experimentally tested in the coming years. The elaboration of the FCC conceptual electro-magnetic designs for the other arc and interaction region magnets largely profited from the long-standing tradition of collaboration at CERN. Most of the involved institutes had already been  responsible for the design and procurement of similar magnet types for LHC and HL-LHC, and also took on the responsibility for magnet types with similar functions for the FCC study. They contributed in a great collaborative spirit to the development of the challenging arc and interaction magnets for FCC (see Fig. 2), as presented in the CDR. 

Fig 2. Electromagnetic baseline designs of the FCC arc and interaction region magnets. The institute taking the lead in the design is indicated in brackets.

Two examples of this collaborative effort for the design of the ‘other’ magnets is the finalisation of a comprehensive design optimisation for the arc quadrupole magnets performed under the lead of CEA. To validate this design, the first winding trials are currently performed by CEA. Another example is the conceptual design established by FNAL for low-luminosity (LL) and high-luminosity (HL) quadrupole triplet magnets with large apertures and gradients. FNAL is continuing their efforts with work on the structural and thermal design, and on a quench protection study. 

The above results prove the value of a strong R&D programme for the successful but also sustainable operation of post-LHC frontier colliders. The FCC collaboration provides a platform for creativity and innovation to flourish in collaboration with research centres and industrial partners from all over the globe. Coordinated R&D efforts can lead towards better technological capabilities for future accelerators that will push further the energy and intensity frontiers in particle physics while they can pave the way for new products and innovation processes.

 
 
 
Panagiotis Charitos
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The RCSM in MgB2 successfully tested at INFN-LASA

In September, the Superconducting Magnet Team at INFN-LASA completed the assembly and test of the so called “Round Coil Superferric Magnet” (RCSM) corrector. This  unconventional magnet creates the desired multipole field through a three dimensional shaping of the iron, excited by simple round coils. The RCSM realised at LASA is also particularly innovative  for using a coil of MgB2 (Magnesium di-Boride based superconductor). The MgB2 superconductor, which is prone to degradation if it is wound with relatively low curvature radius, has demonstrated now to be a practicable option in accelerator magnets with this kind of configuration.

Figure 1: Assembly of the MgB2 superconducting coils in the iron pole and yoke.

G. Volpini (INFN) and E. Todesco (CERN) had considered the RCSMas a possible option for the high order corrector magnets of the interaction regions of the HL-LHC, to be installed in 2025.. However, computations showed that, due to the necessity to increase efficiency in terms of longitudinal space available for the corrector-package, the classical superferric option with Nb-Ti and standard two dimensional iron shaping was preferred. Nonetheless, the MgB2 RCSM prototype magnet has remained in the development line to explore the manufacturing aspects of this design, and to have a MgB2 magnet available for high energy accelerators, a prima for this technology. Last year a single coil conductor, wound with MgB2 produced by Columbus Superconductors (Genova), was tested in LASA without the iron yoke, and the outcome  was reported in Accelerator News 24.

Now an entire module of the magnet, composed of poles, yoke and a single round coil, has been completed, and the test demonstrated the feasibility of this kind of technology. The magnet, cooled at 4.2 K with liquid helium, reached without any training quench the design current (“ultimate current”, 161 A) and demonstrated to be able to operate stable for one hour at the ultimate current. The coil was then energised to larger currents to investigate the limiting current, which resulted 236 A, corresponding to the 78% of the intersection of the load line with the critical current for virgin, not-degraded, conductor (the theoretical limit, in practice never reached in real magnet). It is notable that this current limit has been reached without intermediate quench (no training).

Figure 2: A module of the RCSM assembled and ready to be tested

“We are very happy for this result,” says Massimo Sorbi from INFN-LASA. “This success is the coronation of a long story which started in 2014 by our dear Giovanni Volpini, and we are happy to remember him on this coincidentally  3 years after his departure. After Giovanni, many young researchers and technicians at LASA worked on this exciting project, and I can say that the result we have obtained now is the success of the team. Now that the general functionality of the magnet has been proved, we want to continue with the realisation of additional modules, in order to characterise a complete system from the point of view of magnetic field quality, that is another important assessment that needs to be explored experimentally”.

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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). 

Panos Charitos
Groundbreaking for the HL-LHC civil engineering work
26 Jun 2018

Groundbreaking for the HL-LHC civil engineering work

Civil works have begun on the ATLAS and CMS sites to build new underground structures for the High-Luminosity LHC.

Frederick Savary (CERN)
Full length prototype of an 11T dipole magnet
27 Jun 2018

Full length prototype of an 11T dipole magnet

The construction of the 5.5-m long 11T dipole prototype was completed in May this year after several years of intense work.

Amy Bilton (CERN)
ATS-KT Innovation Days
10 Dec 2018

ATS-KT Innovation Days

The Accelerator and Technology sector (ATS) and the Knowledge Transfer (KT) group jointly hosted the first ATS-KT Innovation Day.

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 (https://forschung.web.cern.ch/).

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:
https://indico.cern.ch/event/663949/timetable/

More information about the photographic exhibition “CODE of the Universe”: cern.ch/cofeoftheuniverse
Isabel Bejar Alonso & Francisco Sanchez Galan (CERN)
A new JTT shielding adapting ATLAS to Hilumi configuration
20 Mar 2019

A new JTT shielding adapting ATLAS to Hilumi configuration

A report/word from HL-LHC Collider-Experiment Interface Work Package

Mike Barnes (CERN)
First workshop on Pulse Power for Kicker Systems held at CERN
28 Jun 2018

First workshop on Pulse Power for Kicker Systems held at CERN

The PULPOKS 2018 workshop brought more than 40 participants to discuss the latest developments in the field of pulsed power for particle accelerators

David Carbajo Perez (CERN)
Installation of the TDIS unit for the High-Luminosity LHC
24 Jul 2020

Installation of the TDIS unit for the High-Luminosity LHC

Nearly one year after the start of the assembly activities the first 3-module-device Target Dump Injection Segmented (TDIS) unit is ready to be installed.

A big step towards the superconducting magnets of the future

Last April, the FRESCA2 dipole magnet reached a field of 14.6T. This field value sets a new world record for dipole magnets with a free aperture, and breaks the old record established in 2008 of 13.8T by LBNL with the HD2 dipole magnet.

The development of magnets with fields beyond 10T started in Europe in 2004 with the FP6-CARE-NED project where the basic technologies were developed and specifically the Nb3Sn conductor which is the workhorse for the HL-LHC 11 T magnet, the LHC luminosity upgrade programme and baseline option for the more powerful 16T magnets for the Future Circular Collider study.

“FRESCA2 has already played an important role in the development of the new magnets for the High Luminosity LHC and will soon help develop the next generation of magnets." says Gijs de Rijk, head of the FRESCA2 programme.

The FRESCA2 dipole magnet design and construction was started in the framework of the FP7-EuCARD-HFM project in 2009 and has been co-financed by HL-LHC. The FRESCA2 magnet is much larger than a LHC magnet, measuring 1.5 m in length and 1 m in diameter. This allows the magnet to have a large aperture, measuring 10 centimetres, so that it can house the cables being tested, as well the sensors to monitor their behaviour. 

The FRESCA2 magnet before the start of the tests. (Image: Maximilien Brice/CERN). 

The magnet is the outcome of a successful collaborative effort between CERN and CEA-Saclay. The technology developments for FRESCA2 were essential for the new Nb3Sn magnets of HL-LHC. Formed by the superconducting niobium-tin compound and cooled to 1.9 kelvin (-271°C), it had already reached a field of 13.3 teslas in August 2017. Then, with a modification of the mechanical pre-stressing, it started a new series of tests in April before reaching its record intensity.

FRESCA2 will also be used to test coils formed from high-temperature superconductors. The goal is to test not only the maximum electrical current but also study in depth the effects of so high magnetic fields and the behaviour of the coil. Results from these measurements feed current efforts to design high-field magnets for future energy-frontier colliders. 

The magnet was tested to the nominal operating field, and achieved 13.3T in August 2017 after a very rapid training of 5 quenches. As a second step, the mechanical preload was increased and the magnet was retested in April 2018 to explore the ultimate operating limit. In this configuration FRESCA2 reached a maximum bore field of 14.6T at a temperature of 1.9K with additional 6 training quenches. The tests are currently being performed in the new purposely built test cryostat of the SM18 cryogenic test station at CERN.

This result is a major milestone in the progression towards high field accelerator magnets beyond HL-LHC. The future of FRESCA2 is to provide background fields for tests of cables and small coils, a new facility that will provide unique test capabilities.

Ricardo Torres (University of Liverpool)
How fundamental science is changing our world
27 Mar 2019

How fundamental science is changing our world

Global FCC study discussed benefits of discovery science to society and industry at Symposium “Particle Colliders – Accelerating Innovation”

Federico Carra (CERN)
A novel composite for HL-LHC collimators
12 Jul 2019

A novel composite for HL-LHC collimators

During the LS2, the LHC collimation system will be upgraded with new primary collimators for halo cleaning and in the dispersion suppression region.

Nadia Pastrone, Daniel Schulte (Muon Collider Group)
Towards a strategic plan for future muon colliders
10 Dec 2019

Towards a strategic plan for future muon colliders

In the context of the European Strategy Update on Particle Physics, a working group was been appointed in 2017 by the CERN Directorate to review the status of muon collider activities.

A new step towards successful MgB2 superconducting coils

On 7th March the INFN-LASA laboratory completed the construction and successfully tested a superconducting coil in MgB2 (Magnesium di-Boride based conductor) to be used in a high order corrector magnet. Development of MgB2 coils for a Round Coil Superferric Magnet corrector was launched in the framework of the HL-LHC project IR magnets. This design, proposed in the 70s by Russian scientists, allows to create any multipole with the same round coil through a three dimensional shaping of the iron; the low curvature radius of the coil allows using MgB2 superconductor. 

Application of this design to the HL-LHC high order correctors started in 2014 by our late lamented Giovanni Volpini with CERN support. Computations showed that this option had a lower efficiency in terms of longitudinal space, and therefore the classical superferric option with Nb-Ti and standard two dimensional iron shaping was retained; INFN-LASA built three correctors based on this design in the past two years, and two more types are being built in collaboration with industry. Nonetheless, the MgB2 RCSM prototype magnet has remained in the development line to explore the manufacturing aspects of this design, and to have a MgB2 corrector available for high energy accelerators, a prima for this technology.

A single coil, wound with conductor produced by Columbus Superconductors (Genova), was tested in LASA without the iron yoke; this coil is the active part of the RCSM magnet, which will be assembled and tested in September 2019. The coil, cooled at 4.2 K with liquid helium, reached without any training quench the specification current (“ultimate current”, 160 A), passing also the stability test of one hour at the ultimate current. The coil was then energized to larger currents to investigate the limiting current, which resulted in 243 A; this is 73% of the intersection of the load line with the critical current for virgin, not-degraded, conductor. It should be noted that this current limit was reached without intermediate quench (no training).


Image Credit: INFN/LASA

“The test result is beyond our expectations,” says Massimo Sorbi from INFN-LASA. “MgB2 virgin conductors are very prone to degradation when they are wound and manipulated with even better procedures used for the other common superconductor magnets based on NbTi. Our cryogenic test was also complemented with the measurement of the thermal contraction of coil (literature is lacking of this data regarding MgB2 coils), which will enable a better design of the mechanical structure for the final magnet.” “This is a relevant technological spin-off of the HL LHC project”, says Ezio Todesco, in charge of HL-LHC IR magnets, “enabled by the synergy between INFN-LASA and CERN”.


Image Credit: INFN/LASA

Mohammed Shahzad (University of Strathclyde)
Laser-wakefield accelerators for High-energy coherent Terahertz radiation
26 Jun 2018

Laser-wakefield accelerators for High-energy coherent Terahertz radiation

Paper just published in New Journal of Physics describes a promising pathway to more efficient radiation sources

Panagiotis Charitos (CERN)
Discussing the next step for circular colliders
12 Dec 2017

Discussing the next step for circular colliders

The 2018 Future Circular Collider collaboration meeting will take place in Amsterdam, the Netherlands (9-13 April 2018).

Isabel Bejar Alonso (CERN)
QUACO Phase-3 starts now
10 Dec 2018

QUACO Phase-3 starts now

Following the competitive tender for phase-3, only two solutions could be awarded a work order. Three were evaluated and considered promising.