Summary of the 2010 LHC Performance Workshop in Chamonix

1. Summary of the 2010 LHC Performance Workshop in Chamonix O. Brüning

2. Chamonix Program Overview Discussion of the LHC performance upgrade path Magnet Splice consolidation IR upgrade Collimation upgrade Injector complex upgrade New Taskforces New planning will emerge by mid 2010 Implications for USLARP ‘new laundry’ list from CERN Contents USLARP CM14 April 2010 Oliver Brüning CERN 2

3. 9 Topical Sessions plus one summary session Preconditions for operating at 5 TeV Magnet Splice Consolidation Optimize interventions in cold sectors (lessons from 2008) Safety for personnel underground: He evacuation Access system & radiation monitors Radiation to electronics Future upgrade scenarios for the injector complex LHC upgrade plans for the ‘first long’ shutdown Additional upgrade scenarios http://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=83135 Chamonix Program Overview USLARP CM14 April 2010 Oliver Brüning CERN 3

4. Magnet splices and beam energy: • 3.5 TeV is still OK for 2010 operation. • 5 TeV operation is risky without repairing Cu splices • Normal shutdown period too short for a full repair • Decision to run through 2010-2011 shutdown with goal of • reaching 1 fb-1 and plan for long shutdown (ca. 1 year in 2012) LHC Upgrade Path: Magnet Splices USLARP CM14 April 2010 Oliver Brüning CERN 4

5. Interconnection splices and resistance at warm • A copper stabilizer with no continuity coupled to a superconducting cable badly soldered to the stabilizer poses a real problem (A. Verweij) Good joint Solder wedge bus U-profile bus Solder No solder Bad joint wedge bus U-profile bus A.Siemko , M.Zerlauth TE/MPE

6. Interconnection splice limitations A.Siemko , M.Zerlauth TE/MPE • Superconducting splices measured with excellent accuracy (at cold), copper stabilizer splices are limiting the top energy • Worst Cu-Cu-splice measured: 60±1μΩ , worst known to exist : 53±15μΩ,worst estimated to exist : 90μΩ • Current knowledge of copper stabilizer splices leaves no margin for operation at 3.5TeV • 5TeV running is excluded without major repairs • Two diagnostic methods are under development to further increase our knowledge of interconnection splices and to spot outliers • A low current method that can measure the RRR of the busbars • A high current method (the Thermal Amplifier) that is sensitive to the worst splices in all bus bar segments

7. -What can the LPSL & PS2 offer for the LHC: •  fully explore any capabilities the LHC may have •  robust and reliable injectors and shorter cycle time •  injector parameters suitable for an LHC energy upgrade • -But: can not be ready before 2022 •  existing complex must run until 2025 •  cost of more than 1.2 BCHF • -Implications for running the existing injector complex for • another 15 years  must be done anyway! • -Possible improvements to the existing injector complex •  Above ultimate bunch intensities possible with PSB upgrade & LINAC4 • -Upgrade needs for the SPS (e-cloud; TMCI; RF power) •  must be done anyway! Ultimate limit in the SPS not yet known! • -Other scenarios for an injector complex upgrade (e.g. RCS; FFAG etc) LHC Upgrade Path: Injector Complex USLARP CM14 April 2010 Oliver Brüning CERN 7

8. Summary of Intensity Limitations in the present Injector Complex G. Arduini et. Al. Chamonix Summary, 5th Feb 2010 Paul Collier & Volker Mertens

9. Conclusions I • The session looked at the possible upgrade of the complex with LP-SPL/PS2 and the present limitations and upgrade possibilities for the existing complex. • The outcome here must be put into the context of what the LHC actually wants • (sessions 8 and 9) • Some things are already very clear: • The present injector complex must run with high performance and high reliability for 15-25 years more. • The present bottleneck in the complex is the SPS and this would remain even with SPL/PS2 • A possible upgrade path in the existing complex by increasing the energy of the PS Booster to 2GeV has been identified Consolidation Plan/Risk Analysis to be done Urgently Launch a Task Force to complete studies and propose upgrade projects. Launch a Study/Project to Upgrade the PSB Energy to 2 GeV Paul Collier & Volker Mertens Chamonix Summary, 5th Feb 2010

10. Seven topical presentations: • -Phase1 IR upgrade overview • -Injector complex upgrades (LINAC4 & PSB modifications) •  LINAC4 can deliver above ultimate beams to the SPS • -Optics challenges for the Phase1 IR upgrade • b* not limited by aperture but rather chrom. aberrations & corr. strength • b* = 0.3m to 0.4m with L = 2-3 1034 cm-2 sec-1 • -Hardware challenges tight & ambitious schedule for 2014-15 shutdown • -Planned RF upgrades (too early for most options: 200MHz capture and damper) • -Summary of collimation upgrade plans and needs • -Integration Issues in the tunnel:  very tight space constraints LHC Upgrade Path: First ‘Long Shutdown’ USLARP CM14 April 2010 Oliver Brüning CERN 10

11. Observations from discussion: • -IR Phase 1 upgrade would be implemented when LHC has reached • an integrated luminosity of at best 50fb-1 compared to a triplet • lifetime of ca. 300fb-1 to 600fb-1 for existing magnets •  tribute to the delays in the LHC startup (September 2008 & 2012 stop) • -Phase1 IR upgrade plan foresees magnet installation long before • LHC injector complex could deliver above ultimate intensities • Limited by SPS  address SPS limitations first • and before remaining HC components are compatible with ultimate • beam intensities e.g. collimation system & cryo upgrade • -How much can be done in one long shutdown (competing resources) • and how many long shutdowns are acceptable LHC Upgrade Path: First ‘Long Shutdown’ USLARP CM14 April 2010 Oliver Brüning CERN 11

12. Timing and cost in machine availability • Overall shut down planning required for the next years before Phase 1 upgrade implementation! • Planning with other required interventions (e.g. splice consolidation). • How can we assure that we can plan for sufficient running time • between the various required shutdowns? • How many and what interventions can be made in parallel? • Resource requirements for total interventions? • How quickly do we think can we reach nominal and ultimate beam • parameters (when do we need to be ready with Phase 1)? • Best timing and earliest practical implementation date for Phase 1? • Shall we revise the scope of the Phase 1 upgrade if we change the • installation date (e.g. allow for modification in the MS)?

13. Summary of LHC Intensity Limits (7 TeV) R. Assman @ Chamonix 2010 R. Assmann Ideal scenario: no imperfections included! Note: Some assumptions and conditions apply… LMC: R. Assmann

14. Future Upgrade Scenarios “Phase 2” • Luminosity Optimization and Levelling • For LHC high luminosities, the luminosity lifetime becomes comparable with the turn round time.. Low efficiency • Preliminary estimates show that the useful integrated luminosity is greater with • a peak luminosity of 5x1034 cm-2 s-1 and luminosity levelling • than with 1035 and a luminosity lifetime of a few hours • Luminosity Levelling by • Beta*, crossing angle, crab cavities, and bunch length • Detector people have also said that their detector upgrade would be much more complicated and expensive for a peak luminosity of 1035 due to • Pile up events • Radiation effects Steve Myers @ Chamonix 2010

15. Conclusions • The Luminosity Targets set by the detectors are: • 3000fb-1 (on tape) by the end of the life of the LHC • → 250-300fb-1 per year in the second decade of running the LHC • The Upgrades needed to attack these goals are • SPS performance improvements to remove the bottleneck • Aggressive consolidation of the existing injector chain for availability reasons • Performance improvement of the injector chain to allow phase 2 luminosities • a newly defined sLHC which involves • luminosity levelling at ~5-6x 1034cm-2s-1 (crab cavities etc…) • At least one major upgrade of the high luminosity insertions Steve Myers @ Chamonix 2010

16. The Chamonix 2010 discussions led to five new task forces: • -Planning for a long shut down in 2012 for splice consolidation • -Long term consolidation planning for the injector complex • -SPS upgrade task force • accelerated program for SPS upgrade • -PSB upgrade and its implications for the PS (e.g. radiation etc) • -IR upgrade task force •  investigate planning for ONE IR upgrade by 2018-2020 Task Forces USLARP CM14 April 2010 Oliver Brüning CERN 16

17. PS2 & SPL studies: -Conceptual design report will be finished by end 2010 -Focus will then shift to SPS upgrade studies and PSB  very strong interest at CERN to redirect USLARP contribution to PSB and SPS studies! Phase 1 upgrade studies: -conceptual design report will be finished by end 2010  APUL contribution put in ‘hibernation mode’  formulation of a ‘new’ IR upgrade following CERN MAC and council meeting (June-July) Implications for USLARP USLARP CM14 April 2010 Oliver Brüning CERN 17

18. CERN’s support needs for refocused upgrade path: • Superconducting magnets (decision 2013 – ready 2018-20) • CRAB cavities • Superconducting links (removal from PC from tunnel; R2E) • Phase 2 collimator • SPS related upgrades (coating; groves; feedback) • Hollow electron lens as primary scraper • Support for the upgrade studies for the PSB • Projected best performance evolution in the LHC: • pay tribute to delays in the LHC startup (September 2008 & 2012 stop) • 2 years of running at lower energy • limitations for operating with above ultimate bunch intensities Conclusions from Chamonix 2010 USLARP CM14 April 2010 Oliver Brüning CERN 18