LHC Collimation Review 2011

Europe/Zurich
CERN

CERN

Mike Seidel (PSI), Ralph Assmann (CERN)
Description
The "phase 1" of LHC collimation has been fully commissioned, allowing a stored beam energy in the LHC of more than 80 MJ. Its performance has been characterized with beam at 3.5 TeV. This review is considering the present performance, possible limitations in future operation and plans for the upgrade of the system. In particular, it should be reviewed whether the upgrade work in the IR3 dispersion suppressors can be delayed by three years without limiting the LHC performance at 7 TeV.

Review Committee:

Mike Seidel (PSI, chair), Tiziano Camporesi (CERN), Wolfram Fischer (BNL), Brennan Goddard (CERN), Mike Lamont (CERN), Thomas Markiewicz (SLAC), Nikolai Mokhov (FNAL), Andrzej Siemko (CERN), Johannes Wessel (U. Muenster)

Charge:
Review collimation status and upgrade plans. Advise on the following questions:
  1. Are collimation performance and limitations properly analyzed and adequately addressed by upgrade plans?
  2. Can the collimation upgrade in the IR3 dispersion suppressors, presently foreseen for the 2013/4 shutdown, be delayed by three years without limiting LHC performance at 7 TeV?
  3. Have any issues or risks been overlooked that should be addressed in the collimation upgrade plan?
Produce a report, summarizing the recommendations and findings. The committee report is linked as document in the "MATERIAL" section.
document
    • 9:00 AM 9:30 AM
      Executive session (closed) Salle Andersson

      Salle Andersson

      CERN

    • 9:30 AM 12:30 PM
      Presentations: Overview on collimation system and present results Salle Andersson

      Salle Andersson

      CERN

      • 9:30 AM
        Welcome 5m
        Speaker: Dr Ralph Wolfgang Assmann (CERN)
      • 9:35 AM
        Introduction to LHC collimation 20m
        Collimation system description: multi-stage cleaning, different planes, betatron and momentum. Definition of cleaning efficiency. Introduction quench limit. Hierarchy. Limiting physics processes: single-diffractive p scattering, ion fragmentation, ... Comments on hollow e-beam scrapers.
        Speaker: Dr Stefano Redaelli (CERN)
      • 9:55 AM
        Discussion 5m
      • 10:00 AM
        Collimation setup and performance 20m
        How is it adjusted? How does it perform in LHC (loss maps: measurement and simulation). MD results at 3.5TeV and performance reach at 7TeV. Losses in luminosity production (dispersion suppressors). Measurement protons vs ions. Minimum beam lifetime. First SPS results BPM’s in jaws.
        Speaker: Daniel Wollmann (CERN)
        Slides
      • 10:20 AM
        Discussion 5m
      • 10:25 AM
        Coffee Break 25m
      • 10:50 AM
        Radiation to electronics 15m
        Issues with radiation to electronics in LHC, with focus on collimation insertions. IR7 versus IR3 sensitivity. Benefit of moving losses from IR7 to IR3.
        Speaker: Markus Brugger (CERN)
        Slides
      • 11:05 AM
        Discussion 5m
      • 11:10 AM
        Collimation margins and beta* 15m
        Stability of LHC machine (orbit, beta). Required margins for collimation setup. Connection collimation to beta*. What beta* can be achieved? Origins of limitations: protection condition, infrequent collimation setups, machine drifts.
        Speaker: Roderik Bruce (CERN)
        Slides
      • 11:25 AM
        Discussion 5m
      • 11:30 AM
        Beam-machine interaction: simulation benchmarking vs first LHC experience 15m
        FLUKA models and predictions. Comparison between measurements and simulations. Safety margins.
        Speaker: Mr Anton Lechner (Atomic Institute of the Austrian Universities, TU Vienna)
        Slides
      • 11:45 AM
        Discussion 5m
      • 11:50 AM
        Collimator design: phase 1 and beyond 20m
        Short description phase 1 design. Second generation collimators. Improved jaw materials. Collimators for cryogenic regions (warm/cold solution).
        Speaker: Alessandro Dallocchio (CERN)
        Slides
      • 12:10 PM
        Discussion 5m
      • 12:15 PM
        Collimation remote handling 10m
        Highlights from work for collimation remote handling and remote survey. Plans.
        Speaker: Keith Kershaw (CERN)
        Slides
      • 12:25 PM
        Discussion 5m
    • 12:30 PM 2:00 PM
      Lunch 1h 30m
    • 2:00 PM 5:40 PM
      Presentations: Motivation and plans for collimation upgrade (with ATS management) 13/2-005

      13/2-005

      CERN

      90
      Show room on map
      • 2:00 PM
        Expectations from Review 5m
        Speaker: Steve Myers (CERN)
      • 2:05 PM
        Collimation project upgrade plan and questions 25m
        Outline of collimation upgrade plan. What is planned when and why? What are the questions arising for this upgrade plan?
        Speaker: Dr Ralph Assmann (CERN)
        Slides
      • 2:30 PM
        Discussion 5m
      • 2:35 PM
        Dispersion-suppressor upgrade IR3 15m
        Foreseen work in IR3 for first long shutdown? Short description. Planning aspects.
        Speaker: Vittorio Parma (CERN)
        Slides
      • 2:50 PM
        Discussion 5m
      • 2:55 PM
        Proton beam performance with and without IR3 upgrade 15m
        What is lost when not doing the IR3 upgrade? Gain from DS collimators. Performance reach without (see also morning presentation) and with dispersion suppressor collimators for protons.
        Speaker: Adriana Rossi (CERN)
        Slides
      • 3:10 PM
        Discussion 5m
      • 3:15 PM
        Ion beam performance with and without IR3 upgrade 15m
        Ion performance reach without and with dispersion-suppressor collimators in IR3. Other ion limitations (IR2, ...). Possible impact from delay of IR3 work on IR2 upgrade of dispersion suppressors.
        Speaker: Giulia Bellodi (CERN)
      • 3:30 PM
        Coffee Break 20m
      • 3:50 PM
        Energy deposition with and without IR3 upgrade 15m
        Predicted energy deposition with and without IR3 dispersion suppressor collimators. Gain from collimators. Performance reach from comparing peak heat deposition with quench limit. Comparison with MD results.
        Speaker: Dr Vittorio Boccone (CERN)
        Slides
      • 4:05 PM
        Discussion 5m
      • 4:10 PM
        Impedance without IR3 upgrade 15m
        Impedance from tight collimation settings as achieved in MD. Will the beams be stable with impedance, taking into account stabilization from transverse damper and octupoles?
        Speaker: Nicolas Mounet (Ecole Polytechnique Federale de Lausanne (EPFL)-Unknown-Unknown)
        Slides
      • 4:25 PM
        Discussion 5m
      • 4:30 PM
        Outcome Risk Review for IR3 Work 20m
        Conclusions from May review in EN/TE departments. Technical feasibility? Major risks? Any show-stoppers identified?
        Speaker: Philippe Lebrun (CERN)
        Slides
      • 4:50 PM
        Discussion 5m
      • 4:55 PM
        Activation issues in dispersion suppressors 15m
        Expected activation levels. Are additional limits expected on work in dispersion suppressors during later shutdowns?
        Speaker: Stefan Roesler (CERN)
        Slides
      • 5:10 PM
        Discussion 5m
      • 5:15 PM
        Radiation damage in dispersion-suppressor magnets 15m
        Can the radiation dose on unprotected magnets in the dispersion suppressors be accepted? What is the radiation hardness and can unacceptable damage to magnets be excluded, for protons and ions?
        Speaker: Dr Davide Tommasini (CERN)
        Slides
      • 5:30 PM
        Discussion 5m
    • 5:40 PM 5:50 PM
      Break 10m
    • 5:50 PM 6:50 PM
      Executive session (closed) 13/2-005

      13/2-005

      CERN

      90
      Show room on map
    • 8:00 PM 10:00 PM
      Review Dinner 2h
    • 9:00 AM 10:30 AM
      Discussion of review committee with ATS and project management (closed) 13/2-005

      13/2-005

      CERN

      90
      Show room on map
      slides
    • 10:30 AM 12:30 PM
      Review committee followup and discussions 13/2-005

      13/2-005

      CERN

      90
      Show room on map
      slides
    • 12:30 PM 2:00 PM
      Lunch 1h 30m
    • 2:00 PM 5:00 PM
      Review committee followup and discussions 13/2-005

      13/2-005

      CERN

      90
      Show room on map
    • 5:00 PM 6:30 PM
      Summary and conclusion (with ATS management) 13/2-005

      13/2-005

      CERN

      90
      Show room on map
      slides