CERN Accelerating science

  Recent progress of the HiLumi project
  by Lucio Rossi (CERN), Agnes Szeberenyi (CERN)

Group photo of the annual meeting participants. Image credit: Claudio Federici, INFN-LNF

A year has already passed since the launch of the High Luminosity LHC Design Study, which is the first step of the larger High Luminosity LHC (HL-LHC) project.

The 2nd Joint HiLumi LHC-LARP Annual Meeting took place on 14-16 November and was hosted by INFN-LNF. The event registered 130 participants, bringing together not only European and US LARP experts but also Japanese and Russian scientists.

The event reviewed the progress of design and R&D of the FP7 HiLumi Work Packages, and of the other HL-LHC WPs as well, and the progress towards a final lay-out of the accelerator upgrade. A dedicated session was organized for young scientists honoured the LARP Toohig fellowship. The plenary talks featured LARP, U.S. DoE and Japanese positions on HL-LHC as well.

The next joint Annual Meeting is planned to take place at Daresbury Laboratory of the Cockcroft Institute in November 2013, while in May 2013 the collaboration will meet at the joint LARP-HiLumi LHC annual meeting in the USA.


  Accelerators in the European Strategy for Particle Physics meeting in Cracow
  by Frank Zimmermann (CERN), Roy Aleksan (CEA)

Open Symposium on the European Strategy for Particle Physics (ESPP2012). Image credit: CERN

From 10 to 12 September 2012 about 500 particle physicists and accelerator experts came together in Cracow, Poland, at an Open Symposium organized by the CERN Council to discuss the future European strategy. The Symposium’s Accelerator Science and Technology Session featured two excellent overview talks, on the energy frontier by Caterina Biscari (INFN-LNF) and on the intensity frontier by Mats Lindroos (ESS, on leave from CERN), which were complemented by a lively discussion.

The smooth operation of the LHC represents a huge success. The measures needed to raise the LHC collision energy up to 13-14 TeV by 2014 are at hand. Work is progressing on the technology for the LHC luminosity upgrade (HL-LHC) around 2020.  Increasing further the collision energy up to 26-33 TeV in the LHC tunnel requires substantial R&D for 16-20 T magnets (HE-LHC). A new 80-km tunnel could allow reaching energies of 80-100 TeV in proton-proton collisions.

Great progress in the SRF development for the ILC makes the construction of a high-energy lepton collider possible. CLIC with two-beam technology could be an alternative if 3 TeV is needed but R&D is still required. A lower-energy CLIC based on klystrons is also proposed. A number of new ideas for circular or gamma-gamma colliders, to study a “Higgs” particle at 125 GeV have also emerged. Much higher energy using leptons requires muon colliders, dielectric RF structures or plasma acceleration, with increasing complexity. High-power proton linacs, such as ESS and IFMIF, are under construction. Neutrino beams will be improved worldwide.

Many R&D topics are common for various accelerators, e.g. high-field magnets, RF structures & RF power sources, particle sources, alignment & stabilization. The conference brought together experts from these areas, highlighting the need to promote further collaborations with other fields of science.

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  New progress for the HiLumi baseline configuration
  by Lucio Rossi (CERN)

Fig1: The U.S. LHC Accelerator Research Program (LARP) consists of four US laboratories, BNL, FNAL, LBNL, and SLAC, who collaborate with CERN on the Large Hadron Collider.

On 3 July, the High Luminosity LHC Parameter and Lay-out Committee (HL-PLC), formed as part of the HiLumi LHC Design Study, selected the maximum possible aperture for the quadrupoles of the inner triplets: 150 mm of coil free bore.

This decision was to get the maximum benefit of the new parameter space by using advanced superconductor Nb3Sn, based on the success of 4-m long, 90 mm aperture LARP quadrupole LQS01b and the 1-m long, 120 mm HQ. This choice was prepared by numerous meetings organized by the Magnets, Accelerator Physics and Performance and Energy deposition work package groups, with participation from CERN, University of Liverpool, US-LARP and KEK.

A recent review of US-LARP (LHC Accelerator Research Program) by DOE-Office of High Energy Physics praised the success of the LARP collaboration that was important in the HiLumi LHC project. In light of the 150 mm aperture size both the Accelerator Physics and the Magnet branches of LARP are readjusting their plans, preparing a construction project for 2015.

Additional progress included a recent meeting dedicated to the lay-out problem of the LHC-Point8 interaction region, especially in the LHCb upgrade era.

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  Illuminating the way from Research to Industry
  by Katherine Chapman (CERN)

Fig 1:Nb3Sn cable needed for the 11tesla superconducting magnets, WP3 of HiLumi. Image credit: CERN
Fig 2: Improving magnet performance (
WP3)  is a key aspect of the High Luminosity LHC upgrade  at CERN (click image to enlarge) Image credit: HiLumi LHC

Euspen’s event in May brought together researchers and industry from around the world, helping to push boundaries in precision engineering. It provided invaluable opportunities for industry to become involved with CERN, including the luminosity upgrade of the LHC.

The two-day event entitled “Precision Engineering at CERN: Future Challenges & Opportunities”, included a number of presentations from keynote speakers and CERN's senior programme managers. The presentation given by Lucio Rossi (HiLumi LHC Project Coordinator) highlighted the precision engineering needed for this advanced upgrade from cryogenic mechanics to equipment and tooling. Industrial expertise in the fields of high vacuum, advanced remote handling and new material development for radiation-hard insulators is vital for this upgrade, which in turn requires infrastructure from civil engineering, electrical engineering and cooling and ventilation.

Given the need for collaboration between science, engineering and industry in the high luminosity upgrade, an Industry information event is planned in spring 2013, in partnership with the TIARA-PP and EuCARD projects. This will focus on superconducting magnets, superconducting radio frequency and cryotechnology, as well as new materials and surfaces. Events like these enhance opportunities for collaboration between science and industry, and create a platform for discussion. Click below to read more about Euspen’s event.

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  LARP’s role in the luminosity upgrade
  by Kate Kahle (CERN)

 Candidates for the LARP Toohig fellowship were evaluated at the May meeting. The Toohig fellowship is named after the late Dr. Timothy Toohig, a physicist and Jesuit priest. Image credit: LARP

What part can US researchers play in the high luminosity upgrade of the LHC? This was one of the key points of the May meeting between the HiLumi LHC project and the US LHC Accelerator Research Program (LARP), which took place in Fermilab, Chicago.

For almost ten years, LARP laboratories (BNL, FNAL, LBNL and SLAC) have been collaborating with CERN in connection with the Large Hadron Collider. Now, with the HiLumi LHC design study underway, the time has come to plan US contribution in concrete terms for the upgrade itself.

LARP has a strong basis in magnet R&D and accelerator physics. For magnets, the move now is to shift from R&D to pre-production prototypes. For accelerator physics, as well as retaining beam-beam studies, there is a growing interest for LARP to participate in crab cavity work.

The May meeting also provided an opportunity to evaluate candidates for the LARP Toohig fellowship. This prestigious opportunity allows post-doctorate researchers to work on LHC activities, dividing their time between CERN and LARP laboratories. Of the four excellent candidates that presented at the May meeting, Silvia Verdu Andres was selected. A second fellowship will be allocated shortly, joining the current Toohig fellows are John Cesaratto (SLAC), Valentina Previtali (FNAL) and Simone White (BNL).

LARP and HiLumi LHC collaborations will continue to be developed, notably with the next joint meeting in Frascati, Italy in November. Presentations from the May meeting are available online.

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  Why do we need a High Luminosity LHC?
  by Kate Kahle (CERN)

Work Packages of the HiLumi LHC FP7 Design Study (WP1-WP6) within the High-Luminosity (HL-LHC) project (click image to enlarge). Image credit: HiLumi LHC

The Large Hadron Collider (LHC) is set to remain the most powerful accelerator in the world for at least two decades. But beyond the run in 2019–2021, halving the statistical error in the measurements will require more than 10 years of running – unless the nominal luminosity is increased by a considerable amount.

To maintain scientific progress and exploit its full capacity, the LHC needs a major upgrade after 2020. The aim is to increase its luminosity by a factor of 5–10 beyond the original design value and provide 3000 fb–1 in 10 to 12 years.

From a physics perspective, operating at a higher luminosity has three main purposes: to perform more accurate measurements on the new particles discovered at the LHC; to observe rare processes that occur at rates below the current sensitivity, whether predicted by the Standard Model or by the new physics scenarios unveiled by the LHC; and to extend exploration of the energy frontier, to increase the discovery reach with rare events in which most of the proton momentum is concentrated in a single quark or gluon.

This has led to the High-Luminosity LHC (HL-LHC) project, which relies on innovative technologies such as cutting-edge 12 T superconducting magnets with large aperture, compact and ultraprecise superconducting cavities for beam rotation, new types of collimators and 300-m long, high-power superconducting links with almost zero energy dissipation. The most technically challenging aspects require CERN to form strong external collaborations, which is why part of the HL-LHC project is grouped under the FP7 HiLumi LHC Design Study. [Edited extract from the CERN Courier]


  Upgrading together, HL-LHC and LIU
  by Kate Kahle (CERN)

The Linac4 accelerator tunnel. Linac4 is the first step of the LHC Injector Upgrade (LIU) project.
Image credit: CERN

On 30 March, participants from the High Luminosity LHC upgrade project (HL-LHC) and the LHC Injector Upgrade project (LIU) held a joint meeting aimed at converging on a set of achievable beam characteristics. After a welcome from Steve Myers, CERN Director of Accelerators and Technology, Mike Lamont gave a summary of the 1st combined meeting held in June 2011.

A talk by Verena Kain describing the transverse emittance blow-up and beam loss presently measured between injection and collision in the LHC itself. Oliver Bruning, deputy project coordinator of HL-LHC, then gave an update of the required beam characteristics at injection energy and Stephane Fartoukh spoke of a micro-batch filling scheme for pacman cancellations. HL-LHC talks concluded with new ideas from Frank Zimmermann including pile-up levelling versus luminosity levelling schemes and the potential gains and losses in performance.

LHC Injector Upgrade talks began with an analysis of the 2011 injector performance by Giovanni Rumolo, after which Brennan Goddard provided an update of achievable beam characteristics at injection. Roland Garoby, head of the LIU upgrade, commented on the means to bridge the gap between the HL-LHC requirements and the potential of the injectors.

In a question and answer session in the afternoon, discussions included the pros and cons of 25 and 50 nanosecond bunch spacing, and of overlapping LIU and LHC beam parameters. A summary will soon be linked to the agenda but for now all presentations are available online.