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View From CERN / Schedule. O. Brüning. Acknowledgment: The whole LHC operation team and in particular the LHC Machine Coordinators (most transparencies taken from the LHC 8:30 meetings): G. Arduini, R. Assmann, B. Holzer, J. Uythoven, J Wenninger, M. Lamont,.
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View From CERN /Schedule O. Brüning Acknowledgment: The whole LHC operation team and in particular the LHC Machine Coordinators (most transparencies taken from the LHC 8:30 meetings): G. Arduini, R. Assmann, B. Holzer, J. Uythoven, J Wenninger, M. Lamont,
Launch of a dedicated study for doubling the beam energy in the LHC HE-LHC • 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) • -LHC High Luminosity project • investigate planning for ONE upgrade by 2018-2020 Upgrade Studies and Taskforces Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 2
High Luminosity LHC Projects: L. Rossi • prepare for operation at 5 1034 cm-2 sec-1 • prepare for integrated luminosity of 3000 fb-1 (200 fb-1 to 300 fb-1 / y) • Ready for implementation by 2020 • LHC Injector Upgrade Project: R. Garoby • remove bottlenecks in the PS and SPS • investigate options for PSB upgrade (energy) • LHC Consolidation Project: S. Baird • have to consolidate existing injector complex for at least 15+ years Linear Collider Project: Steinar Stapnes New Project Structure at CERN as of 2010 Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 3
Pre 2010 Operation Goals! Chamonix 2010: • Two years at 3.5 TeV • 2010: should peak at 1032 cm-2 sec-1 • 2011: ~1 fb-1 at 3.5 TeV • 2012: splice consolidation (and cryo collimator prep.) • 2013: 6.5 TeV - 25% nominal intensity • 2014: 7 TeV – 50% nominal intensity Aggressive M. Lamont @ Chamonix 2010 Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011
LHC protons 2010: mission accomplished 250 bunches with ca. 2.6 1013 ppb L0 > 1032 cm-2 s-1 Emittance in collision < 3 mm Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011
Status LHC Stored Energy @ end 2010 Stored energy reached at 3.5 TeV: 28.0 MJ 80 kg TNT Ralph Assmann USLARP DOE Review, FNAL 1-2 June 2011
Overall LHC efficiency in 2010 65%availability! Great achievement for the first year of operation! W. Venturini USLARP DOE Review, FNAL 1-2 June 2011 7
Physics operations ~30%Stable beams! W. Venturini USLARP DOE Review, FNAL 1-2 June 2011
2010 - records Courtesy Atlas USLARP DOE Review, FNAL 1-2 June 2011
Aperture measured aperture better than expected allows further reduction of b* b* = 1.5m Emittance able to operate the LHC with 50% smaller than nominal beam emittances (aperture & brightness) beam-beam: able to collide beams with larger than nominal beam-beam parameters Summary Operation Experience in 2010: • ability to exceed the luminosity target from Chamonix 2010 • potential for achieving > 5 fb-1 @ 3.5 TeV within 2 years Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 10
Estimated Peak and Integrated Luminosity b* = 1.5m M. Meddahi @ Chamonix 2011 Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011
LHC running in 2012 to benefit from potential for reaching more than 5 fb-1 before first long shut down. Remain at 3.5 TeV beam energy due to unacceptably high risks for machine operation at beam energies above 3.5 TeV Prepare for 18 month long shutdown in 2013 – 2014 Commissioning and operation at 7 TeV in 2015 and 2016 Upgrade LHC in 2017 to be compatible with operation with above nominal beam intensities (LINAC4 & Collimation upgrade) Chamonix 2011 decisions: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 12
[Outcome Chamonix 2011 presented @ LMC 81 - draft] CERN plan for coming years Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011
2011: main goals • Motivation is clear! • 1 fb-1 delivered to each of IP1, IP5 and IP8 at 3.5 TeV • Can probably do better for IP1 and IP5 • It will be a challenge to deliver 1 fb-1 to IP8 • Maximum luminosity : from 2e32 to 3e32 cm-2 s-1 • Luminosity leveling via separation required to get close • Alice • pp run: 5e29 < L < 5e30 cm-2 s-1, leveled by beam separation fast, secure and far-reaching Decided on beta* = 1.5 m in Atlas, CMS; 3 m in LHCb; 10 m in Alice (from Chamonix 2011 discussions) USLARP DOE Review, FNAL 1-2 June 2011
LHC schedule 2011 Q1 & Q2: 11 weeks of p CM16 Today M. Lamont @ LMC 26. May 2011 USLARP DOE Review, FNAL 1-2 June 2011
LHC schedule 2011 Q3 & Q4: 15 weeks of p • Original schedule foresaw long shutdown in 2012 • V2.0: end of run brought forward by 5 days to allow cryogenics enough time to prepare for technical stop M. Lamont @ LMC 26. May 2011 USLARP DOE Review, FNAL 1-2 June 2011
2011 summary M. Lamont March2011 USLARP DOE Review, FNAL 1-2 June 2011
Transfer line and multi bunch injection setup: -Transfer line trajectories more reproducible then in previous year -establish injection with up-to 48 per injection & operation with 200 bunches with 75 ns bunch spacing Optics measurement and validation: -5% beta-beat at 3.5 TeV and aperture: global > 12 s, triplet > 14.5 s Collimation system setup: -achieved setup time of ca. 25min / collimator tank -Leakage to cold elements of ca. 10-4 at 3.5 TeV Performance achievement: -emittance = 2.5 mm in collision (3.75 mm) @ 1.2 1011 ppb -ca.15 MJ stored beam energy -L = 2.5 1032 cm-2 sec-1 with 194 colliding bunches -max fill luminosity: 7.3 pb-1; 28 pb-1 in one week Re-Commissioning with beam: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 18
Optics measurement and validation: -ca. 20% beta-beat at 1.38 TeV Performance achievement: -emittance = 2.5 mm in collision (3.75 mm) @ 1.1 1011 ppb -ca. 80 bunches per beam with 525ns bunch spacing -delivered ca. 34 hours of collisions to Alice (as requested) Observations: -Van der Meer luminosity scans routinely done (no impact on beam) -Beam-beam effects stronger than at 3.5 TeV -Beam lifetimes shorter than at 3.5 TeV (ca. 5h as compared to > 25h) Operation at 1.38 TeV: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 19
Bunch configuration: -Scrubbing done with 50ns bunch spacing -Injection of batches with trains of 12 to 72 bunches -Injection of up to 96 bunches (4*24) and 144 bunches (4*36) from SPS for 75ns and 50ns bunch spacing done as preparation for later operation Signatures for electron cloud activity: -Vacuum pressure in warm regions -He cooling power on beam screens in cold sections -emittance blowup along bunch trains in the LHC -RF phase shift Electron Cloud Scrubbing run: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 20
General Observations during scrubbing run: -Satellite bunches with bunch train injection -Systematic shift in BPM reading as function of bunch pattern -Non-conformities in components (e.g. swapped cable in QPS for S45) Scrubbing setup and observation: -Intensity increase done in steps of 200 bunches: started with 377 bunches per beam reached 1020 bunches per beam at the end of the scrubbing run more than 1014 protons per ring -Vacuum improvements with time constant of ca. 4 hours scrubbing could provide conditions consistent with 50ns operation Electron Scrubbing run: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 21
General Observations: • -UFO rate larger for longer bunch trains • -some abnormal heat loads in some cryo cells (RF contacts?) • -Multi-bunch and head-tail instabilities for operation with large number • of bunches: • operation with damper at all times (Q and Q’ measurement difficult!) • requires very tight control of Q’ during whole operation cycle • (magnet modeling, correction via data base & reproducibility!) • goal: dynamic Q’ correction to 1 unit +/- 1 unit • -first signs of R2E (regular access for QPS; collimator position control) • -observation of vacuum spikes (triplet and injection area) • -No beam-beam limit reached yet (record hadron beam-beam parameter) Performance ramp up: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 22
UFOs – unidentified falling objects • Many sudden local losses have been recorded. • No quench, but preventive dumps • Rise time around of the order 1 ms. • Potential explanation: dust particles falling into beam creating scatter losses and showers propagating downstream • Distributed around the ring – arcs, inner triplets, IRs USLARP DOE Review, FNAL 1-2 June 2011 23
UFO rates versus intensity T. Baer G. Arduini @ 8:30 Meeting end April 2011 24 USLARP DOE Review, FNAL 1-2 June 2011
Performance achievement: -emittance = 2.5 mm in collision (3.75 mm) @ 1.1 <-> 1.3 1011 ppb -more than 80 MJ stored beam energy per ring; -L > 1.25 1033 cm-2 sec-1 with beam life time > 25 h in collision 1092 bunches per ring and 1042 colliding bunches in IR1 and IR5 -max fill luminosity: ca 38 pb-1 / fill; ca. 165 pb-1 in one week -total delivered integrated luminosity: > 500 pb-1 L = 2 1033 cm-2 sec-1 & 200 pb-1 / week within reach for rest of the year Performance ramp up: Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 25
Intensity ramp-up after Technical Stop • Several good fills with 1042 bunches • Suffered from several Cryogenic problems after technical stop • Focus on luminosity production during this week: • > 200 pb-1 / week within reach total of 2 to 3 fb-1 in reach for the year • Next step to 1200 bunches • requires 144 bunches/injection (new setup) • Last step for intensity ramp up: 1380 bunches per beam well on track for Chamonix 2011 goals! USLARP DOE Review, FNAL 1-2 June 2011
Several vital studies for LHC performance upgrade: -Collimation studies review @ CERN in June (rotatable collimator jaws, crystal collimation, hollow e-lens) tests of rotatable collimator prototypes are planned in the SPS and the CERN HiRadMat facility -Beam instrumentation (AC dipole, L, SLM, Schottky) AC dipole was the key ingredient for achieving optics corrections to 10% level SLM established as key tool for beam diagnostics during ramp (only means for measuring beam size at all energies and bunch by bunch & abort gap monitor) -LL-RF vital tool for controlled beam blow-up during ramp (IBS) USLARP –CERN Collaboration Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 27
Several vital studies for LHC performance upgrade: -Broad band feedback as means against e-cloud (SPS upgrade) very efficient setup with combined simulation and feedback studies; this is a very promising and attractive (manageable intervention) remedy for e-cloud effect in SPS -CRAB cavity development as key ingredient to HL-LHC All HL-LHC scenarios rely on CRAB cavities for luminosity leveling -Beam dynamic studies (beam-beam, optics ) USLARP is a vital partner in the High Lumi Design study (beam-beam, optics & lattice, simulations, e-cloud, parameter optimization) USLARP –CERN Collaboration Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 28
Several options for future contributions for LHC hardware upgrades -electron cloud feedback system -collimation etc ( see Lucio Rossi’s presentation) Toohig fellowship and Long Term Visitor program: -Very much appreciated by CERN -Very effective integration into the LHC operation -Very attractive synergies between existing (US) expertise and LHC needs (e.g. AC dipole and optics measurements; Schottky, Collimation) USLARP –CERN Collaboration Oliver Brüning BE-ABP USLARP DOE Review, FNAL 1-2 June 2011 29
Conclusions: an excellent start in 2011! on the back of excellent availability, great machine performance Number of issues – SEEs being probably the one with the potential to hit availability… USLARP DOE Review, FNAL 1-2 June 2011
Assumed beam parameters for Physics Malika Meddahi
cooling & e- heat for 25 ns spacing L. Tavian, 2005 H. Maury Cuna, 2009 “ultimate” nominal spare cooling capacity at zero luminosity (=total-SR -impedance) ACES 2011 Workshop, CERN, March 2011 e-cloud heat load for SEY=1.3 spare cooling capacity for 0.55 m b* Oliver Brüning BE-ABP going above Nb=1.7x1011 & ultimate luminosity requires dedicated IR cryo plants; limit then becomes Nb~2.3x1011
cooling & e- heat for 50 ns spacing L. Tavian, 2005 H. Maury Cuna, 2009 spare cooling capacity at zero luminosity (=total-SR -impedance) (longer flat bunches) spare cooling capacity for 0.25 m b* ACES 2011 Workshop, CERN, March 2011 e-cloud heat load for SEY=1.5! Oliver Brüning BE-ABP going above Nb=2.3x1011 & ultimate luminosity requires dedicated IR cryo plants; limit then becomes Nb~5.0x1011