first thoughts on MD Priorities for 2012

Frank Zimmermann, Ralph Assmann, Giulia Papotti 2012 LHC Operation Workshop

Evian, 12-14 December 2012

many thanks for input from Gianluigi Arduini, Philippe Baudrenghien, Chiara Bracco, Roderik Bruce, Oliver Brüning, Florian Burkart, Helmut Burkhardt, Stephane Fartoukh, Werner Herr, John Jowett, Verena Kain, Mike Lamont, Elias Metral, Nicolas Mounet, Lene Norderhaug Drosdal,

Yannis Papaphilippou, Federico Roncarolo, Mariusz Sapinski, Marek Strzelczyk, Rogelio Tomas, Georges Trad, David Valuch, LSWG ++

2011 MD highlightsmany outstanding results• high beam-beam tune shift: 0.034 total in two IPs • high brightness beam: 1 micron beam with 2x1011 ppb• high bunch intensity 2.5x1011 protons; all instrumentation working• 25-ns beams up to 2100 bunches • injection of 288 nominal bunches • tight collimation settings • 0.5 MW beam losses at collimators w/o quench• p-Pb MD: feasibility of mixed beams in LHC• high pile-up of up to 35 events per crossing• ATS optics b* down 40 cm• UFO events much faster than expected from gravity• limiting IR aperture factor ~1.5 bigger than expected documentation in ~30 MD notescoordination w. injectors worked extremely well (Giulia & Giovanni)

MD Results: Bunch Intensity & Emittance

Ralph Assmann, C-MAC 22 August 2011

2011 MD NotesBI MD studies on August 25th 2011, D. Belohrad et al, CERN-ATS-Note-2011-130 MDEnd-of-fill study on collimator tight settings , R. Assmann et al, CERN-ATS-Note-2011-125 MD Optics measurement and correction close to the half integer resonance, R. Calaga et al,CERN-ATS-Note-2011-124 MD. - 2011.Results of long range beam-beam studies and observations during operation in the LHC, Alemany et al, CERN-ATS-Note-2011-120 MDIR1 and IR5 aperture at 3.5 TeV, C. Alabau Pons,,CERN-ATS-Note-2011-110 MDBeam parameters observations during a high pile-up collisions fill, G. Trad et al, CERN-ATS-Note-2011-105 MDLongitudinal Oscillations with Batch Injection in the LHC, T. Argyropoulos et al, CERN-ATS-Note-2011-031 MDDependence of single beam lifetime on bunch length, P. Baudrenghien et al, CERN-ATS-Note-2011-083 MDTight collimator settings with beta* = 1.0 m, R. Assmann et al, CERN-ATS-Note-2011-079 MD.R2E-related MD: slow controlled losses for RadMon/BLM cross-checks , M. Calviani et al, CERN-ATS-Note-2011-070 MDBI MD Studies on June 29th 2011, D,Belohrad et al.CERN-ATS-Note-2011-069 MDQuench Margin at Injection, W. Bartmann et al, CERN-ATS-Note-2011-067 MDMKI UFOs at Injection, T. Baer et al, CERN-ATS-Note-2011-065 MDMD on Injection Quality – Longitudinal and Transverse Parameters , L. Drosdal et al, CERN-ATS-Note-2011-063 MDImproving LHC Collimator Setup Efficiency at 3.5 TeV, Assmann et al, CERN-ATS-Note-2011-062 MDIR3 combined cleaning test at 3.5 TeV, R. Assmann et al, CERN-ATS-Note-2011-061 MD.LHC Transvers Profile Monitors studies (MD on May 6th, 2011), E. Bravin et al, CERN-ATS-Note-2011-049 MD Transverse coupled-bunch instability rise times in the LHC at injection and top energy, N. Mounet et al, CERN-ATS-Note-2011-035 MDHead-on beam-beam tune shifts with high brightness beams in the LHC, R. Alemany et al, CERN-ATS-Note-2011-029 MDTest of luminosity levelling with separated collisions , R. Alemany et al, CERN-ATS-Note-2011-028 MD50 and 75 ns operation in the LHC: Vacuum and Cryogenics observations, G. Arduini et al, CERN-ATS-Note-2011-046 MDBPM Offset Determination by Sinusoidal Quadrupole K-modulation, T. Baer et al, CERN-ATS-Note-2011-043 MDThe Achromatic Telescopic Squeezing (ATS) MD part I, S. Fartoukh et al, CERN-ATS-Note-2011-033 MDSummary of MD on nominal collimator settings, R. Assmann et al, CERN-ATS-Note-2011-036 MDUn-squeeze to 90 m, H. Burkhardt et al, CERN-ATS-Note-2011-032 MDCollimator losses in the DS of IR7 and quench test at 3.5 TeV, R. Assmann et al,CERN-ATS-Note-2011-042 MDStudies of longitudinal single bunch stability, T. Argyropoulos et al, CERN-ATS-Note-2011-041 MDTI8 shielding studies and angular alignment of TDI and TCDQ, W. Bartmann et al, CERN-ATS-Note-2011-040 MD

2011 MD review:how much time was allocated* per topic

electron cloud: 62 hinjection & inj. protection: 50 hATS optics: 47 hbeam-beam: 40.5 hBI: 40 h collimation: 34 hRF&longit. dynamics: 34 hmagnets incl. quench tests: 31 hb*=1 m (opt+coll): 22 h IR MDs: 18 hnonlinear dynamics: 18 h impedance: 10 (15) h

b*=90 m: 10 hUFO studies: 8 (16) hcollisions tunes at inj. & ramp: 8 hR2E: 8 h1/2 integer tune: 8 hp-Pb feasibility: 8 hTDI vacuum: 8combined ramp & squeeze: 8 hhigh pile up: 7 hADT blow up at injection: 6 hp-p rephasing: 6 hbeam shape: 2 h

*beam may not have been available for all the time

2012 schedule

4 MD blocks of 5 days each,and 2x24 h floating MDs

2012 MD requestsMD requests for 2012 submittedin November & December 2011

76 requests in total

total time requested: 913.5 havailable time: 528 h

distribution of MD requests

Optics MD Requests (106 h)

ATS optics: 16 hTune close to ½ integer: 16 hCompensation of IR nonlinearities: 12 hNonlinear beam dynamics: 12 hMovements IT with beams at injection: 8 hRF cavity nonlinearities: 16 hAperture measurements at 3.5 TeV w ADT blow up:

8 hLHC linear chromaticity: 6 hChromaticity measurement w. longitudinal kick: 8 h

Beam-Beam MD Requests (136 h)

Head-on beam-beam limit w unequal beams: 16 h Beam-beam limit for LR separation: 24 hBeam-beam limit for LR intensity: 8 hLarge Piwinski angle: 16 hTransverse noise & coherent beam-beam: 16 h Beam-beam emittance growth due to transverse

noise: 16 hLR beam-beam with flat beams: 24 hHV passive compensation: 16 h

Collimation MD Requests (120 h)Chromatic aberrations & collimation: 8 hAsynchronous dump in collimation set up: 8 h Scraping scan for beam shape: 8 hCollimation studies with different settings: 24 hScraping with tune excitation: 16 hLoss maps with transverse damper: 8 hCollimation with beta*=40 cm: 8 hFast collimator setup at 3.5 TeV: 8 hProton collimation loss mitigation: 16 hCollimation cleaning eff. on ramp w ADT blow up: 8 hFast beam losses at the collimators: 8 h

ADT MD Requests (18 h)

High pile up: 8 h Luminosity levelling with beta* change: 8 h

Noise properties of ADT with FB on and off: 6 hResidual tune signal in damper signal: 6 hADT Q/Q’ diagnostics compatibility: 6 h

Detector MD Requests (16 h)

Impedance&Inst. MD Requests (110 h)TCBI at flat top and octupole stabilization: 20 hImpedance budget at injection: 6 hMultibunch tune shift at flat top: 8 hMultibunch tune shift at injection: 8 hProbing the single bunch limits in LHC: 6 hLHC transverse impedance: 10 hImpedance and beam heating of long protection devices: 16 hIntensity limitations for 25 ns operation: 24 h Effective longitudinal broadband impedance: 6 hLoss of Landau damping during ramp: 6 h

Emittance Growth MD Requests (38 h)

Source of transverse emittance blow up: 16 hTransverse emittance blow up at injection: 10 hOptimization of ADT in the ramp: 12 h

High beta* MD Requests (16 h)

De-squeeze to beta*=500 m: 8 h Scraping to 1 micron emittance at top energy: 8 h

Quench Threshold MD Requests (56 h)

Quench margin at top energy in DS of IR7 & IR3: 16 hQuench limit investigations with beam at injection at

Q6.L8 & Q4.L6: 16 hWire scanner quench test at flat top for ms losses:

8 hQuench test at injection energy for MQ/MB with horizontal bump: 8 hQuench test at nominal energy at C14R2 with bumps:

8 h

Injection MD Requests (80 h)

Beam losses at injection: 16 hProtection from long devices: 16 hInjection matching & emittance preservation: 16 hLHC transfer line stability: 16 hTransfer and injection of high brightness bunches

with SPS Q20: 16 h

RF MD Requests (68 h)

Longitudinal blow up studies: 16 hRF feedback optimization with circulating beam: 4 hCommissioning of longitudinal damper: 16 hLongitudinal stability for batch: 16 hVoltage modulation to minimize klystron power:

16 h

Ion MD Requests (40 h)Ion collimation loss mitigation: 16 h Proton lead intensity limit: 16 h Commissioning of p-Pb rephasing using p: 8 h

BI MDs: 36 hUFO MDs: 8 hOperational development MD: 48 hSensitivity of QPS thresholds to FB systems: 8 hCombined ramp & Squeeze: 8 h

Other MD Requests (108 h)

EOF MD Requests (>2.5 h)Halo scraping: 0.5 hTCBI at flat top and injection: 1 hSingle bunch parameter evolution: ?Automatic K modulation for beta*: 1 h

Chromaticity decay at flat top: 3 h

SOF MD Requests (3 h)

MPS classes• class A: setup beams

– automatically approved• class B: unsafe beams with physics conditions, any energy

• (no changes of optics or orbit)

– to be approved on a case by case by rMPP (“quick approval”)• class C : unsafe beams and changes of orbit/optics

– safe and controlled machine conditions must first be established with Setup Beams

– approval with EDMS document including:• responsibilities to establish and validate new beam conditions (eventually including

orbit/optics changes)• detailed description of the steps during the MD• the steps and responsibilities to re-establish and validate nominal conditions after the MD

• class D: unsafe beams involving new ‘machine territory’ – drastic changes of the optics, WP…– downgraded to Setup Beam unless full failure analysis is performed, in which

case the MD is moved to class C

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#requests

2012 main MD themes

[time in hours]

these MDsshould comeearly

Theme 1: pushing performance in 2012• beam transfer

- injection lines, transfer stability, injection protection• BI MDs• operational efficiency

- combined ramp & squeeze• emittance growth at injection and ramp• emittance growth in collision

- beam-beam & noise- collisions without ADT or different ADT gains

• p-Pb MDs- p-Pb feasibility- p-Pb phasing with protons- ATS IBS studies (no MD request)

Theme 2: preparing for 2014/15• 6.5 TeV energy

- quench margin; combined ramp & squeeze; BI limits

- collimation: nominal 6.5/7-TeV settings• high pile up

- ATS optics, collimation w b*=40 cm & low emittance• 25 ns (after scrubbing)

- (electron cloud, UFOs) - long-range beam-beam effects - maximum current (vacuum, cryo, impedance)- RF & longitudinal dynamics MDs

• shorter bunches - heating, vacuum, loss of Landau damping

• high beta* optics- maximum b*, injection w. b*=200 m, ATS de-

squeeze

Theme 3: towards maximum luminosity• SPS Q20 optics

- transfer and injection matching• ATS optics

- enhanced Landau damping- (beam-beam limit for ATS)- effect on IBS rates

• collimation MDs- maximum acceptable chromatic aberrations- halo diffusion control by tune mod., loss mitigation

• beam-beam limits & optimization- HV passive compensation- half integer tune, flat beams- large Piwinski angle

• alternative leveling methods

possible improvements for 2012

• more EOF MDs• SOF MDs• make use of intensity increase

we assume that there will be no operational development

what is MD, what is commissioning?

1. example: 90 m optics – feasibility shown in MD; commissioning for physics run done in physics time

2. example: high pile up – first test and feasibility in MD; data taking in physics time

flexibility from everybody helped to accomplish major goals

now:

what is the preliminary view on most important topics?

most important – preparing for 6.5 TeV• BI with potential hardware improvement

- BPM stability for b*=0.55 m & nominal collimation- resolve BSRT systematics at 4 TeV in view of 6.5 TeV

• RF- klystron power issues, voltage modulation for transient b.l.- transverse damper ultimate performance

• OP - feedback stabilization of orbit in squeeze

• Collimation- settings with nominal 1-s retraction, impedance

• Quench limits - relevant BLM thresholds at different energies

• Heating - understand HOM, longitudinal spectrum

• Injection- fast & accurate steering of transfer line

most important – preparing for 6.5 TeV• 50 ns or 25 ns?

- high pile up limit- bunch intensity & emittance growth limits- electron cloud- crossing angle & LR beam-beam separation

• High beta optics- limits with present hardware

• Nonlinear dynamics limits- required specification for 11-T dipoles- required specification for crab cavities

most important – new hardware

outlook• the lists & thoughts presented here are

meant as a basis for discussion• iteration in January• final 2012 MD priorities will be summarized

in Chamonix for approval

any feedback is welcome - please send comments to Giulia, Ralph and/or Frank!

MD Priorities 2012together we will straighten them out