De Christophe Grojean et Laurent Vacavant Librio
Broché : €3
Vous n’avez rien compris au boson de Higgs ? Alors ce petit livre est peut-être fait pour vous. Il faut saluer en effet le très grand effort des auteurs pour tenter de rendre accessible à tous les concepts qui se cachent derrière l’une des plus grandes découvertes de ces dernières années.
De la relativité au mécanisme qui donne leur masse aux particules, en passant par la physique quantique, cet ouvrage aborde le plus simplement possible les notions qui permettront à chacun d’appréhender le monde complexe des particules ainsi que les lois du Modèle standard. Les nombreuses analogies – souvent drôles – aident à rendre concrets des phénomènes le plus souvent abstraits que seul le formalisme mathématique est en mesure de réellement retranscrire. Vous découvrirez notamment dans cet ouvrage pourquoi le père Noël ne peut être qu’un objet quantique vu son comportement (c’est de saison), ou encore pourquoi la recherche du boson de Higgs revient à chercher un tibia de mammouth dans un immense cimetière d’éléphants !
Bien sûr, les spécialistes et les puristes trouveront certainement des défauts à certaines analogies : nul doute que nous n’avons pas terminé de discuter sur la meilleure manière de présenter simplement le mécanisme de Higgs… L’avantage de ce petit livre, c’est aussi qu’en moins d’une centaine de pages, il aborde les grandes étapes de l’aventure du LHC en les replaçant dans le contexte historique et international. Il rend également compte des stratégies et technologies mises en œuvre dans les expériences ATLAS et CMS pour enregistrer et traiter une quantité de données vraiment phénoménale.
Je recommande donc sans hésitation la lecture de cet ouvrage pour sa concision, sa simplicité et son approche légère qui devrait ravir tous ceux dont la vue d’une simple équation est en mesure de provoquer une indigestion.
By Alan Owens CRC Press
Hardback: £82
Also available as an e-book
Bringing together information scattered across many disciplines, this book summarizes the status of research in compound semiconductor radiation detectors. It examines the properties, growth and characterization of compound semiconductors as well as the fabrication of radiation sensors, with emphasis on the X- and γ-ray regimes. It explores the limitations of compound semiconductors and discusses current efforts to improve spectral performances, pointing to where future discoveries might lie. A resource for the established researcher, this book serves as a comprehensive and illustrated reference on material science, crystal growth, metrology, detector physics and spectroscopy. It can also be used as a textbook for those who are new to the field.
Anyone trying to apply the solid knowledge of quantum field theory to actual LHC physics – in particular to the Higgs sector and certain regimes of QCD – inevitably meets an intricate maze of phenomenological know-how, common lore and intuition, often historically grown, about what works and what does not. These lectures are intended to be a brief but sufficiently detailed primer on LHC physics that will enable graduate students and any newcomer to the field to find their way through the more advanced literature, as well as helping them to start work in this timely and exciting field of research.
Following a resolution unanimously adopted at the 169th session of the CERN Council on 12 December, CERN is set to admit Israel as the organization’s 21st member state. Israeli membership will be effective from the date on which Israel formally notifies UNESCO that it has ratified the CERN Convention. CERN was established under the auspices of UNESCO, and UNESCO remains the depository of the CERN Convention. Israeli has been an associate member of CERN since 2011.
Israel’s formal association with CERN began in 1991, when the country was granted observer status by Council in recognition of the major involvement of Israeli institutions in the OPAL experiment at the Large Electron–Positron collider, accompanied by contributions to the running of the accelerator. Today, Israel is involved with the ATLAS experiment at the LHC and the ALPHA and COMPASS experiments, as well as experiments at the ISOLDE facility. In addition, Israel contributes to the LHC and to the CLIC accelerator design study, and operates a tier-2 centre of the Worldwide LHC Computing Grid. Israel also supports the involvement of Palestinian students at CERN.
Israel’s forthcoming membership of CERN follows a decision taken by Council in 2010 to enlarge the organization’s membership. At the same time, Council established the status of associate membership for countries wishing to have limited participation in CERN’s programme, accompanied by limited benefits of membership. All new applicants for full membership must pass through a period of at least two years as an associate member before Council takes a decision on full membership. A country can also apply for associate membership in its own right.
Following this decision, Israel became CERN’s first associate member in 2011, followed by Serbia in 2012. Cyprus and Ukraine will become associate members as soon as their national parliaments ratify the accession agreements. Discussions are still underway with Slovenia regarding membership, and with Brazil, Pakistan, Russia and Turkey, all of which have applied for associate membership. Romania has the status of candidate for accession, having applied for full membership before the new procedures came into effect.
On 29 September, it will be 60 years since CERN – the European Organization for Nuclear Research – came into being as the first scientific pan-European endeavour. Just a few years after the Second World War, 12 European countries joined forces and built what has become the world’s largest particle-physics laboratory. To mark the anniversary, this year CERN will celebrate 60 years of cutting-edge science for peace. In this issue, CERN’s current director-general writes how the organization has fulfilled the vision of its founders to provide for collaboration among European states in pure and fundamental scientific research “with no concern for military requirements” (Viewpoint: A celebration of science for peace). Celebratory events will take place throughout the year in the member states – now numbering 21 – and at CERN. In particular, at the beginning of July a joint event with UNESCO in Paris will mark the anniversary of the initial signing, in 1953, of the convention that was to establish the organization under the auspices of UNESCO a year later. On 29 September, an event at CERN attended by high-level representatives from all of the member states will celebrate – 60 years to the day – the official birth of the organization in 1954.
• For more about 60 years of CERN in this and future issues of CERN Courier, look out for the logo!
After intense preparations and consensus building, the SCOAP3 open-access publishing initiative started on 1 January. With the support of partners in 24 countries, a large proportion of scientific articles in the field of high-energy physics will become open access at no cost for any author: everyone will be able to read them; authors will retain copyright; and generous licences will enable wide re-use of this information. Convened at CERN, this is the largest-scale global open-access initiative ever built, involving an international collaboration of more than 1000 libraries, library consortia and research organizations. SCOAP3 enjoys the support of funding agencies and has been established in co-operation with leading publishers.
Eleven publishers of high-quality international journals are participating in SCOAP3. Elsevier, IOP Publishing and Springer, with their publishing partners, have been working with the network of SCOAP3 national contact points. Reductions in subscription fees for thousands of participating libraries worldwide have been arranged, making funds available for libraries to support SCOAP3.
The objective of SCOAP3 is to grant unrestricted access to articles appearing in scientific journals, which so far have been available to scientists only through certain university libraries, and generally unavailable to the wider public. Open dissemination of preliminary information, in the form of pre-peer-review articles known as preprints, has been the norm in high-energy physics and related disciplines for two decades. SCOAP3 sustainably extends this opportunity to high-quality peer-review service, making the final version of articles available within the open-access tenets of free and unrestricted dissemination of science with intellectual property rights vested in the authors and wide re-use opportunities. In the SCOAP3 model, libraries and funding agencies pool resources that are currently used to subscribe to journals, in co-operation with publishers, and use them to support the peer-review system directly instead.
• Partners in the following countries have formalized their participation in SCOAP3: Austria, Belgium, Canada, China, Denmark, France, Germany, Italy, Japan, Norway, Portugal, Sweden, Switzerland, United Kingdom and the United States of America. Partners in the following countries are completing the final steps to formally join SCOAP3: the Czech Republic, Finland, Greece, Hungary, Korea, the Netherlands, Spain, South Africa and Turkey.
The following publishers and scientific societies are participating in SCOAP3 with 10 high-quality peer-reviewed journals in the field of high-energy physics and related disciplines: the Chinese Academy of Sciences, Deutsche Physikalische Gesellschaft, Elsevier, Hindawi, Institute of Physics Publishing, Jagellonian University, Oxford University Press, Physical Society of Japan, SISSA Medialab, Springer, Società Italiana di Fisica.
When the CERN Council approved the updated European Strategy for Particle Physics at a special meeting in Brussels last May, it recognized the High Luminosity LHC (HL-LHC) project as the top priority for CERN and Europe. A month later, after Council had approved its integration into the CERN Medium Term Plan for 2014–2018, the HL-LHC entered a new phase, as it passed from design study to an approved project.
To mark this approval, the 3rd joint annual meeting of the HiLumi LHC Design Study and the US LHC Accelerator Research Program (LARP) took place in conjunction with the HL-LHC kick-off meeting. The event was held in November at Daresbury Laboratory in the UK, bringing together more than 160 scientists from countries around the world, including Japan, Russia and the US. Directors of major accelerator laboratories were present as invited speakers.
The kick-off meeting underlined the role of the HL-LHC as a necessary tool for extending physics beyond the LHC. The important roles of CERN and the high-energy physics community were also emphasized. Developing new technologies – for example, magnets with a field 50% above the present LHC technology – opens the way for a future higher-energy machine requiring even higher magnetic fields, such as the recently proposed Future Circular Collider.
Highlights reported by the design-study work-package leaders at the meeting included final parameters for the layout and finalized main layout for the machine; important developments in crab-cavity hardware; a detailed layout for improving collimation; and the assembly and characterization of two 10-m-long MgB2 cables that have been tested up to 5 kA and at 20 K in the superconducting-link configuration.
The HL-LHC project is currently in the design and prototyping phase and should release a Preliminary Design Report in the middle of 2014, with the Technical Design Report for construction at the end of 2015.
Given the broad international collaborations involved in major scientific user facilities, timely formal and informal discussions among leaders of physics societies worldwide contribute to fortifying the scientific case that is needed to justify large, new enterprises. The past year, 2013, proved to be one of focused introspection and planning for major research facilities, conducted by learned societies and by government agencies in Asia, Europe and the US. All three regions developed visions for particle physics and in the US the government developed priorities and plans for a broad spectrum of scientific user facilities.
The Asia-Europe Physics Summit
In July, in Makuhari, Chiba, Japan, the third Asia-Europe Physics Summit (ASEPS3) – a collaboration between the Association of Asia Pacific Physical Societies and the European Physical Society – provided a forum for leaders in the respective physics communities to discuss strengthening the collaboration between Europe and the Asia-Pacific region (Barletta and Cifarelli 2013). These summits have three main goals: to discuss the scientific priorities and the common infrastructure that could be shared between European and Asian countries in various fields of physics research; to establish a framework to increase the level of Euro-Asia collaborations during the next 20 years; and to engage developing countries in a range of physics research. This year’s summit centred on international strategic planning for large research facilities. It also included a significant US perspective in three of the four round-table discussions.
High-energy physics programmes received particular focus
Round Table 1 offered perspectives on the technologies that enable major research facilities, while Round Table 2 looked to the issues of policy and co-operation inherent in the next generation of large facilities. High-energy physics programmes received particular focus in the discussion, where the three regions of Asia, Europe and the US have their own road maps and strategies. This round table clearly provided a special opportunity for a number of leaders and stakeholders to exchange their views. Participants in Round Table 4 discussed training, education and public outreach – in particular the lessons learnt and challenges from large research laboratories. Although the science motivations for major user facilities differ widely, many of the underlying accelerator and detector technologies – as well as issues of policy, international co-operation and training the next generation of technical physicists and engineers – are nonetheless in common.
Because both the update to the European Strategy for Particle Physics and the Technical Design Report for the International Linear Collider (ILC) had been issued by the time of the summit, and because the Snowmass process in the US was well under way, major facilities for particle physics set a primary, although far from exclusive, context for the discussions.
The European Strategy for Particle Physics
In January, a working group of the CERN Council met in Erice to draft an updated strategy for medium and long-term particle physics. That document was remitted to the Council, which formally adopted the recommendations in a special meeting hosted by the European Commission in Brussels in May. As expected, the updated strategy emphasizes the exploitation of the LHC to its full potential across many years through a series of planned upgrades. It also explicitly supports long-term research to “continue to develop novel techniques leading to ambitious future accelerator projects on a global scale” and to “maintain a healthy base in fundamental physics research, in universities and national laboratories”. In a period in which research funding is highly constrained worldwide, these latter points are a strong cautionary note that maintaining “free energy” in national research budgets is essential for innovation.
Beyond the focus on the LHC, the strategy recommends being open to engaging in particle-physics projects outside of the European region. In particular, it welcomes the initiative from the Japanese high-energy-physics community to host the ILC in Japan and “looks forward to a proposal from Japan to discuss a possible participation”. That sentiment resonated strongly with many participants in the 2013 Community Summer Study in the US, especially in the study groups on the energy-frontier study and accelerator capabilities. In September, the Asia-Pacific High Energy Physics Panel and the Asian Committee for Future Accelerators issued a statement that “the International Linear Collider (ILC) is the most promising electron positron collider to achieve the objectives of next-generation physics.”
The 2013 US Community Summer Study
In the spring of 2012, the Division of Particles and Fields of the American Physical Society (APS) commissioned an independent, bottom-up study that would give voice to the aspirations of the US particle-physics community for the future of high-energy physics. The idea of such a non-governmental study was welcomed by the relevant offices of both the US Department of Energy (DOE) and the National Science Foundation (NSF). The APS study explicitly avoided prioritizing proposed projects and experiments in favour of providing a broad perspective of opportunities in particle physics that would serve as a major input to an official DOE/NSF Particle Physics Project Prioritization Panel (P5). The study was broadly structured into nine working groups along the lines of the “physics frontiers” – energy, intensity and cosmic – introduced in the 2008 P5 report and augmented with studies of particle theory, accelerator capabilities, underground laboratories, instrumentation, computing and outreach. In turn, the two conveners of each working group divided their respective studies into several sub-studies, each with three conveners, generally.
Beginning with a three-day organizational meeting in October 2012 and culminating in a nine-day session at the end of July/beginning of August 2013 – “Snowmass on the Mississippi” – the 2013 Community Summer Study involved nearly 1000 physicists from the US plus many participants from Europe and Asia. Roughly 30 small workshops were held in 2013 to prepare for the “Snowmass” session at the University of Minnesota, which was attended by several hundred physicists.
Snowmass activities connected with the energy frontier were strongly influenced by the discovery of a Higgs boson at the LHC. Not surprisingly, the scientific opportunities offered by the LHC and its series of planned upgrades received considerable attention. The study welcomed the initiative for the ILC in Japan, noting that the ILC is technically ready to proceed to construction. One idea that gained considerable momentum during the Snowmass process was the renewed interest in a very large hadron collider with an energy reach well beyond the LHC.
The conclusions of each of the nine working groups are presented in a summary report, which defines the most important questions for particle physics and identifies the most promising opportunities to address them in several strategic physics themes:
• Probe the highest possible energies and distance scales with the existing and upgraded LHC and reach for even higher precision with a lepton collider. Study the properties of the Higgs boson in full detail.
• Develop technologies for the long-term future to build multi-tera-electron-volt lepton colliders and 100 TeV hadron colliders.
• Execute a programme with the US as host that provides precision tests of the neutrino sector with an underground detector. Search for new physics in quark and lepton decays in conjunction with precision measurements of electric dipole and anomalous magnetic moments.
• Identify the particles that make up dark matter through complementary experiments deep underground, on the Earth’s surface and in space, and determine the properties of the dark sector.
• Map the evolution of the universe to reveal the origin of cosmic inflation, unravel the mystery of dark energy and determine the ultimate fate of the cosmos.
The study further identifies and recommends opportunities for investment in new enabling technologies of accelerators, instrumentation and computation. It recognizes the need for theoretical work, both in support of experimental projects and to explore unifying frameworks. It calls for new investments in physics education and identifies the need for an expanded, co-ordinated communication and outreach effort.
Summary
Although the activities of 2013 on possible perspectives and scenarios for major science facilities were neither a worldwide physics summit nor a worldwide physics study, they served to open the door for extensive engagement by physicists to build a compelling science case for major research facilities in Asia, Europe and the US. They identified ways to increase the scientific return on society’s investment and to spread the benefits of forefront physics research to developing countries.
During the meetings in 2013, it became clear that a possible future picture could be construction of the ILC in Japan and a long baseline neutrino programme in the US, while Europe exploits the LHC and prepares for the next machine at the energy frontier, which can be defined only after LHC data obtained at 14 TeV in the centre of mass have been analysed. Therefore, despite highly constrained research budgets worldwide, future prospects look bright and promising. They represent today’s challenge for the next generation(s) of scientists in a knowledge-based society.
Following the presentations at the Open Symposium in Cracow in September 2012 and a great deal of work by the European Strategy Group for Particle Physics, the update to the 2006 European Strategy for Particle Physics was published in 2013 and adopted at a special European Strategy Session of CERN Council in Brussels on 30 May (CERN Courier July/August 2013 p9). In developing its vision for the future, the updated strategy took full account of the massively important discovery of a Higgs boson at the LHC in 2012 and of the global research landscape. For the programme at CERN, it contains the clear message: “Europe’s top priority should be the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with a view to collecting ten times more data than in the initial design, by around 2030. This upgrade programme will also provide further exciting opportunities for the study of flavour physics and the quark–gluon plasma.”
The priority given to the high-luminosity upgrade, dubbed the High-Luminosity LHC (HL-LHC), underlines the importance of the ongoing machine and detector developments for this facility, including supporting studies on performance and physics reach. Indeed, there has been highly active R&D in the required accelerator and detector technologies, following the recommendations of the 2006 strategy document. Much of this work has been conducted within the four large LHC experimental collaborations or – for the accelerator complex – within the framework of the EU-funded HiLumi LHC Design Study (CERN Courier March 2012 p19).
A three-day forum
With the recent update of the European Strategy, the HL-LHC project is expanding rapidly and the idea of an HL-LHC Experiments Workshop sponsored by the European Committee for Future Accelerators (ECFA) was conceived to offer a forum for the experimental collaborations to share results, explore synergies and to strengthen links with the machine and theoretical communities. After a concerted effort, colleagues in theory, the four big LHC collaborations and the accelerator community – co-ordinated through eight preparatory groups – organized three intensive days of workshop at the Centre des Congrès, Aix-les-Bains, on 1–3 October.
After an opening on behalf of ECFA by its chair Manfred Krammer, CERN’s Frédérick Bordry presented the latest plans for the accelerator upgrade. The ALICE, ATLAS, CMS and LHCb collaborations then gave overviews of their strategy to follow the planned increase in machine luminosity. This will proceed with staged upgrades, installed across a decade during end-of-year technical stops and two long access periods (long shutdowns) required for the major modifications. Many of the detailed plans are already documented in reports to CERN’s LHC Committee (LHCC) and more are in advanced stages of preparation. To round off the first morning, CERN’s director-general, Rolf Heuer, gave the laboratory’s perspective on the HL-LHC programme, underlining planning for the next 20 years at the LHC and the thinking on future directions, taking CERN forward to its centenary celebrations in 2054.
The HL-LHC is designed to deliver in every year of operation 10 times the number of collisions collected at the LHC to date
The experimental collaborations presented many updates to the studies on physics’ prospects that were documented at the Cracow Open Symposium and at the “Snowmass” meeting in Minneapolis in summer 2013, based on a better understanding of the expected experimental performance. This was complemented with a broad theoretical survey of the rich physics programme at the energy frontier offered by the HL-LHC facility. The extremely high number of collisions to be recorded in a year at the HL-LHC provides the opportunity to look for rare processes, study systems with high mass and make high-precision measurements.
The HL-LHC is designed to deliver in every year of operation 10 times the number of collisions collected at the LHC to date, yielding 10 times more data by the end of HL-LHC operation than the LHC is expected to have delivered by around 2022. This gives unprecedented sensitivity in measurements of a range of properties of the newly found Higgs boson, as well as in searches for new high-mass particles, and allows precision studies of a variety of fundamental particles and processes. In addition, should the 13–14 TeV running this decade lead to further discoveries of new particles, the HL-LHC will be essential to measure their properties.
Discussion then focused on areas where the machine and experiment teams need to work most closely: beam parameters, instrumentation and interfaces, shutdown planning and radiation protection. There were presentations of exciting new ideas that might allow the inherent problem of high-luminosity operation – the huge number of interactions every bunch crossing – to be mitigated by extending the interaction region along the beam direction.
This “pile-up” of interactions, the high data rates and the level of integrated radiation doses, will be the major experimental challenges for operation in the HL-LHC’s beam conditions. For the workshop, the areas of detector-upgrade preparations were split into those relating to tracking, calorimetry, muon systems, read-out electronics and triggering, data acquisition, offline software and computing. Each topic was covered in a dedicated session, where joint presentations across the four big experiments addressed the motivation, requirements and conceptual designs for upgrades, as well as the ongoing R&D programmes to provide efficient and cost-effective technical solutions.
For HL-LHC operation, major activities in ATLAS and CMS are related to the replacement of the tracker, owing to the high number of tracks per bunch crossing, the read-out bandwidth limitations and the integrated radiation levels that go far beyond the capabilities of available technologies at the time of their original construction. The much higher data rates also motivate a number of upgrades to other parts of the experiments, especially to their read-out electronics. In particular, the complexity of the collision events will complicate greatly the ability of the vital on-detector data-reduction (triggering) to retain only those events that are interesting to physics. Many improvements are aimed at refining this online selection. The detector, electronics, trigger and data-acquisition upgrades in ATLAS and CMS have been designed to optimize the physics acceptance, especially for the key decay channels of the Higgs boson, including those rare decays that can be reached only at the HL-LHC.
The rich programmes in flavour and heavy-ion physics were discussed from the perspective of all four experiments, but the focus for upgrades was on the dedicated experiments, LHCb and ALICE, which are designed to optimize their sensitivity to these areas of physics. Detector upgrades will extend that sensitivity and allow a greatly increased number of collisions to be recorded, improving the statistical precision for measurements and studies of rare processes significantly. These upgrades do not rely on implementing the HL-LHC machine upgrades and so can be undertaken earlier to bring these improvements sooner.
There were a number of closing presentations emphasizing the key themes from the workshop, which were formulated in a short report to ECFA at its meeting on 21–22 November. This report reflects the interest of those organizing the sessions in seeing more specialist follow-up meetings and a similar plenary meeting, possibly in autumn 2014.
The organizers would like to thank all those who contributed to the work of the preparatory groups, the speakers and chairs, the conference support from CERN and particularly the ATLAS and CMS secretariats. The success of the event was a great testament to the enthusiasm of the 326 registered participants and the many more researchers worldwide working on R&D towards this major further step in the LHC’s unique adventure at the high-energy frontier.
The EuCARD project for accelerator R&D came to an end on 31 July 2013, more than four years after starting on 1 April 2009. The project’s focus has been generic and targeted R&D for frontier accelerators in the fields of particle physics, nuclear physics and synchrotron radiation applications. Many accelerator infrastructures or projects were involved, including the upgrades for the LHC at CERN; the Facility for Antiproton and Ion Research (FAIR); the European free-electron laser project, XFEL, and FLASH at DESY; and the studies for the Compact Linear Collider (CLIC) and International Linear Collider (ILC).
A framework for collaborative R&D finds its justifications in the extreme technological challenges, the synergies between projects or studies and the complementary competences of laboratories, universities and institutes. R&D naturally precedes the design stage but is not confined to it. It continues during the lifetime of the accelerator to allow the large infrastructures to remain at the forefront of research and make the best use of society’s significant investments.
The EuCARD project was initiated by the European Steering Group on Accelerator R&D (ESGARD) as successor to the Coordinated Accelerator Research in Europe (CARE) project, which ran under FP6 from 2004 to 2008. Its total cost was €36 million, with €10 million covered by a European Union Seventh Framework Programme (FP7) grant. The remaining €26 million came through matching funds from the 38 EuCARD partners, who represent most of the European accelerator laboratories, as well as a large number of universities and specialized institutes. CERN provided co-ordination and project management. The project’s work was organized around three poles: scientific networks, open access to facilities and collaborative research activities.
Following CARE, the EuCARD networks have consolidated their positions as recognized platforms for the international exchange of ideas and experts – from Europe, Japan, the US, and beyond. Providing support for accelerator centres, they organized more than 50 topical workshops on diverse themes, from electron-cloud mitigation, through RF test stations, crab cavities and so on, to long-term visions of future developments.
The networks originally included neutrino facilities, accelerators and colliders (performance and RF technologies). Later, another network was launched on laser-plasma acceleration, with the primary goal of federating the many European research teams around a common road map. The ambitious objective was to collaborate on a transition from the demonstration of the plasma-wakefield concept to operational accelerators. The network bridges the gap between accelerator, laser and plasma communities and after a successful start is now funded fully in EuCARD’s successor – EuCARD-2.
A main objective and result of the neutrino networks was to contribute to the update to the European Strategy for Particle Physics by allowing the community to discuss strategies and prepare summary documents, one of which was submitted to the update process. The community acknowledges the conclusions of the updated strategy, which recognizes the need to re-establish an accelerator-based programme at CERN.
A major outcome of the accelerator networks is an ambitious vision for future facilities for high-energy physics, from the LHC luminosity and energy upgrades through unconventional lepton and photon colliders to hadron colliders in the 100 TeV range (figure 1). This effort, which included helping to define key R&D areas for the coming decades, has the potential to guide debates on the future of frontier accelerators at a European level.
Transnational access
Two test facilities were open in EuCARD to transnational access: HiRadMat at CERN’s Super Proton Synchrotron (SPS) and MICE at the Rutherford Appleton Laboratory (RAL). The European Commission funding of these activities was dedicated mostly to the support of visits and research by new users.
HiRadMat – the High Irradiation to Materials facility – was constructed at CERN in 2011 to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator components can be tested (figure 2). During the duration of EuCARD, nine user projects and 19 users were supported via transnational access (HiRadMat@SPS). When the SPS restarts in autumn 2014, the facility will be open to transnational access in the framework of EuCARD-2. Several communities have already expressed interest.
The UK’s Science and Technology Facilities Council (STFC) provided transnational access to a specialized precision beamline at the Muon Ionization Cooling Experiment (MICE) at the ISIS facility at RAL. A total of 19 researchers from eight institutes were supported for 131 visits during EuCARD’s lifetime.
Joint research activities had the lion’s share in EuCARD, with 87% of the total budget, about 50 objectives that led to concrete results and as many reports containing scientific results. Many of the developments are described in the EuCARD Final Report, soon to be published as a EuCARD monograph. Here are a few highlights.
Under EuCARD, R&D was initiated in Europe for the first time on high-field Nb3Sn magnets (figure 3) and on high-temperature superconducting (HTS) yttrium barium copper oxide (YBCO) inserts. Together, these initiatives are ushering in the era of magnets with fields in the 20 T range. After overcoming many challenges with these delicate superconductors – such as the high strains, insulation and required resistance to radiation – the work is well advanced, with the final results expected in two years. Success will open the door to a new generation of accelerators at the energy frontier, including the energy upgrade of the LHC. In the nearer future, it will allow the upgrade of CERN’s FRESCA test station for superconducting cables, which is used also by the ITER fusion project, for example. Other possible application areas could be nuclear magnetic resonance and magnetic resonance imaging.
The HTS electrical-link demonstrator at CERN is fully operational. It will allow energy-efficient remote powering of magnets. This will have a positive impact on the LHC upgrade, allowing powering away from radiation areas. The principle, studied in collaboration with industry, may also find applications in the energy domain.
Studies of new robust materials for beam collimation have pointed to metal–diamond or metal–graphite composites that offer promising solutions when increasing the energy or power of accelerator beams. The use of HiRadMat was instrumental in the characterization of these novel, more robust materials. The “smart” LHC collimator and the cryo-catcher for FAIR (figure 4) were designed, built and successfully tested with beams.
EuCARD’s contribution to linear colliders is deeply integrated in the CLIC and ILC studies. Significant progress was made in the ultra-precise assembly and integration of RF modules, thermal stabilization, ultra-precise phase control to 20 fs and beam control. The active mechanical stabilization of magnets to a fraction of a nanometre is especially impressive, as are the highly sophisticated simulations of RF breakdowns, which show new microscopic mechanisms and offer directions for mitigation. The study of an innovative compact crab cavity also gave momentum to this R&D line, going well beyond the original plans with the fabrication of a bulk-niobium superconducting unit. This is now part of the baseline LHC luminosity upgrade project.
In other work on superconducting RF, the strategy for fabrication and processing of cavities for proton linacs should set a new higher standard for accelerating gradients. This is of relevance for all proton linacs, for example for the European Spallation Source and accelerator-driven systems. Progress has been made on the delicate process of sputtering a thin film of niobium onto a copper RF cavity, but full validation remains to be done. Experts believe that this technique – pioneered for phase 2 of CERN’s Large Electron-Positron collider – could reach much higher gradients, well in excess of the performance of bulk niobium, which has reached close to its theoretical limit. High-performance cavities also require higher-performance RF couplers to feed them. The R&D on an automatic cleaning machine is a step forward, needing a demonstrator, and promises to decrease significantly the cost and duration of the processing of couplers for large accelerators.
In the field of diagnostics and control, FLASH is benefiting from an upgraded modular low-level RF, with the novelty that it is based on a commercial telecommunication standard. Already being commissioned, it provides a significant gain in field stability. Such a control system could be used by the XFEL or adapted for the ILC.
EuCARD also set aside about 10% of its budget for joint research studies on unconventional concepts, such as crab-waist crossing, diagnostics for the nonscaling fixed-field alternating gradient machine EMMA at Daresbury Laboratory, and emittance measurements for the widely diverging beams of laser-plasma accelerators. This could lead to interesting contributions to the field.
Making an impact
By co-funding scientific research, the European Union (EU) aims to strengthen the collaboration between European institutes and universities, to implement the well-known adage “union is strength”. Therefore each project must evaluate its impact on a progressive integration of effort.
EuCARD’s main impact has probably been to encourage scientists at accelerator centres to adapt to collaborative working methods that involve distributed work and decision making. Challenges are, in a first phase, the minimization of overheads as a result of collaborative working methods requiring more reporting, for example; and in a second phase, to make best use of the added potential of collaborative work. Like CARE and other European projects, EuCARD has provided invaluable hands-on experience in this context to its members – inspired by the organization of the particle-physics community, but adapted to the field of accelerators with its different boundary conditions.
Beyond this qualitative impact, EuCARD’s legacy will include a series of scientific monographs on accelerator sciences. In addition, a quarterly newsletter, Accelerating News, created by EuCARD, was extended to all EU accelerator projects and beyond, and now reaches more than 1100 subscribers. Both will continue serving the community via EuCARD-2 and the TIARA project.
The project has contributed to the birth of other FP7 ventures, such as HiLumi-LHC
Other impact has been at the EU policy level, where accelerator R&D was ranked highly in a survey among EU project co-ordinators. The project has contributed to the birth of other FP7 ventures, such as HiLumi-LHC, and allowed stronger co-operation via networks with laboratories in the US and with KEK in Japan, the latter now being a full member of HiLumi-LHC. EuCARD also established a bridge with the FP7 project ICAN, with its focus on high-power high-repetition-rate lasers potentially suitable for laser acceleration.
Experience with EuCARD has enabled the concept for Enhanced European Coordination for Accelerator R&D – EuCARD-2 – to be defined in ESGARD. This next phase of co-ordinated accelerator R&D started on 1 May. It will run for four years with a total budget of €23.4 million and provide a framework for 40 research institutes across the world. EuCARD-2 has networks on innovation, energy efficiency, accelerator applications, extreme beams, low-emittance rings, and novel accelerators. HiRadMat@SPS will continue to provide access for new users, as will the Ionisation Cooling Test Facility – ICTF@RAL. The R&D activities will address the technological limits of current machines with regard to magnetic fields, RF gradients and technologies, and collimator materials. There will also be dedicated activity on plasma-wakefield acceleration as an alternative to current approaches.
To provide the best experiences, we use technologies like cookies to store and/or access device information. Consenting to these technologies will allow us to process data such as browsing behavior or unique IDs on this site. Not consenting or withdrawing consent, may adversely affect certain features and functions.
Functional
Always active
The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network.
Preferences
The technical storage or access is necessary for the legitimate purpose of storing preferences that are not requested by the subscriber or user.
Statistics
The technical storage or access that is used exclusively for statistical purposes.The technical storage or access that is used exclusively for anonymous statistical purposes. Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you.
Marketing
The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes.
