HLLHC BeamBeam Notes and Plan A Valishev FermilabUS

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HL-LHC Beam-Beam Notes and Plan A. Valishev (Fermilab/US LARP), T. Pieloni (CERN) November 4,

HL-LHC Beam-Beam Notes and Plan A. Valishev (Fermilab/US LARP), T. Pieloni (CERN) November 4, 2013 Acknowledgments: D. Banfi, J. Barranco, S. Fartoukh, D. Shatilov The Hi. Lumi LHC Design Study (a sub-system of HL-LHC) is co-funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. Fermi Research Alliance, LLC operates Fermilab under Contract DE-AC 02 -07 CH 11359 with the US Department of Energy. This work was partially supported by the US LHC Accelerator Research Program (LARP).

Outline • Approach • Tools and methods 30 Oct. 2013 • Work plan and

Outline • Approach • Tools and methods 30 Oct. 2013 • Work plan and issues A. Valishev, HL-LHC beam-beam 2

Approach • Evaluate HL-LHC scenarios and options to identify potential limitations from beam-beam •

Approach • Evaluate HL-LHC scenarios and options to identify potential limitations from beam-beam • Criteria / observables • Dynamical aperture > 6(7? )s • Nominal LHC design based on 7 s (real) • Collimators at 6 s (3. 75 mm) -> 7. 3 s (‘real’ 2. 5 mm) • Simulated emittance growth / luminosity life • Large DA is necessary but not sufficient for successful machine operation • Orbit, Q, Q’ • Same as nominal bunches: DA & Lumi lifetime A. Valishev, HL-LHC beam-beam 30 Oct. 2013 • Bunch-by-bunch (PACMAN) effects 3

Tools • Lifetrac • Six. Track üFull element-by-element lattice ü 6 D weak-strong beam

Tools • Lifetrac • Six. Track üFull element-by-element lattice ü 6 D weak-strong beam • weak-strong beam-beam üWire compensator üFMA, DA, multi-particle ? 6 D ? Crab Cavity ? Wire compensator • DA ? FMA 30 Oct. 2013 üCrab Cavity ü 4 D A. Valishev, HL-LHC beam-beam 4

Tools ? Bunch-by-bunch (PACMAN) effects 30 Oct. 2013 ? TRAIN A. Valishev, HL-LHC beam-beam

Tools ? Bunch-by-bunch (PACMAN) effects 30 Oct. 2013 ? TRAIN A. Valishev, HL-LHC beam-beam 5

Lifetrac/Six. Track without beam-beam slhcv 3. 1 b, 7 Te. V, b*=10 cm, beam-beam

Lifetrac/Six. Track without beam-beam slhcv 3. 1 b, 7 Te. V, b*=10 cm, beam-beam off • emittance 3. 75 mm, Dp/p=2. 7 E-4, 105 turns DA • Sixtrack data provided by • Lifetrac Task 2. 3 M. Giovannozzi • 59 angles • Same seeds • 30 particle pairs for 2 sigma intervals • 90 angles • 22 particle pairs for 2 sigma intervals A. Valishev, HL-LHC beam-beam 30 Oct. 2013 • 60 seeds 6

Lifetrac/Six. Track without beam-beam 105 turns DA: very good agreement Seed #1 Seed #2

Lifetrac/Six. Track without beam-beam 105 turns DA: very good agreement Seed #1 Seed #2 30 Oct. 2013 Agreement based on 10 seed comparison better than 5% A. Valishev, HL-LHC beam-beam 7

Lifetrac/Six. Track without beam-beam 105 turns DA: very good agreement seed #6 seed #4

Lifetrac/Six. Track without beam-beam 105 turns DA: very good agreement seed #6 seed #4 seed #5 seed #7 seed #8 30 Oct. 2013 seed #3 A. Valishev, HL-LHC beam-beam 8

Lifetrac/Six. Track with beam-beam slhcv 3. 1 b, 7 Te. V, multipole errors off

Lifetrac/Six. Track with beam-beam slhcv 3. 1 b, 7 Te. V, multipole errors off • emittance 2. 5 mm, Dp/p=2. 7 E-4, 106 turns DA • Sixtrack • Lifetrac • 17 angles • 30 particle pairs for 2 sigma intervals • 22 particle pairs for 2 sigma intervals 30 Oct. 2013 • averaging over initial betatron phase A. Valishev, HL-LHC beam-beam 9

Lifetrac/Six. Track with beam-beam 106 turns DA: b*=15 cm, 590 mrad Np=2. 2 E

Lifetrac/Six. Track with beam-beam 106 turns DA: b*=15 cm, 590 mrad Np=2. 2 E 11 Np=2. 8 E 11 30 Oct. 2013 TODO: repeat with Lifetrac without phase averaging, to establish that the difference is not from different DA definition in two codes A. Valishev, HL-LHC beam-beam 10

Lifetrac/Six. Track with beam-beam 106 turns DA: b*=10 cm, 720 mrad Np=2. 8 E

Lifetrac/Six. Track with beam-beam 106 turns DA: b*=10 cm, 720 mrad Np=2. 8 E 11 30 Oct. 2013 Np=2. 2 E 11 A. Valishev, HL-LHC beam-beam 11

Lifetrac/Six. Track with beam-beam 105 turns DA: Np=2. 2 E 11, d=0 b*=10 cm,

Lifetrac/Six. Track with beam-beam 105 turns DA: Np=2. 2 E 11, d=0 b*=10 cm, 720 mrad 30 Oct. 2013 b*=15 cm, 590 mrad A. Valishev, HL-LHC beam-beam 12

Lifetrac/Six. Track with beam-beam 106 turns DA: b*=5/20 cm, 670 mrad Np=2. 8 E

Lifetrac/Six. Track with beam-beam 106 turns DA: b*=5/20 cm, 670 mrad Np=2. 8 E 11 30 Oct. 2013 Np=2. 0 E 11 A. Valishev, HL-LHC beam-beam 13

30 Oct. 2013 105 turns DA: Lifetrac vs. Sixtrack b*=5/20 cm, 670 mrad, Np=2.

30 Oct. 2013 105 turns DA: Lifetrac vs. Sixtrack b*=5/20 cm, 670 mrad, Np=2. 2 E 11, d=0 A. Valishev, HL-LHC beam-beam 14

Lifetrac/Six. Track with beam-beam • Need to understand the in origin of discrepancy between

Lifetrac/Six. Track with beam-beam • Need to understand the in origin of discrepancy between Ltr. /Sx. 4 D/Sx. 6 D • Observation: difference for particles with Dp/p=0 is small – synchrobetatron effects? • TODO 30 Oct. 2013 • More elaborate benchmarking: turn off long-range, etc. A. Valishev, HL-LHC beam-beam 15

Importance of multiparticle simulation: Nominal LHC: DA 30 Oct. 2013 106 turns DA: b*=55

Importance of multiparticle simulation: Nominal LHC: DA 30 Oct. 2013 106 turns DA: b*=55 cm, 285 mrad, Np=1. 12 E 11 DA>7 s - consistent with LHC design A. Valishev, HL-LHC beam-beam 16

Importance of multiparticle simulation: Nominal LHC: FMA Tune spread is ~0. 01, no strong

Importance of multiparticle simulation: Nominal LHC: FMA Tune spread is ~0. 01, no strong resonances. No beam-beam? A. Valishev, HL-LHC beam-beam 30 Oct. 2013 212 turns FMA: b*=55 cm, 285 mrad, Np=1. 12 E 11, d=0 17

Importance of multiparticle simulation: Nominal LHC: FMA for off-momentum particles shows significant synchrobetatron resonances!

Importance of multiparticle simulation: Nominal LHC: FMA for off-momentum particles shows significant synchrobetatron resonances! A. Valishev, HL-LHC beam-beam 30 Oct. 2013 212 turns FMA: b*=55 cm, 285 mrad, Np=1. 12 E 11, d=2 s 18

Importance of multiparticle simulation: Nominal LHC: multiparticle 5 106 turns, 10, 000 particles: b*=55

Importance of multiparticle simulation: Nominal LHC: multiparticle 5 106 turns, 10, 000 particles: b*=55 cm, 285 mrad, Np=1. 12 E 11 * probably overestimated by a factor 2 due to constant strong beam A. Valishev, HL-LHC beam-beam 30 Oct. 2013 t. L=1. 8 hours !!!* 19

Multiparticle simulation: 2012 LHC 5 106 turns, 10, 000 particles: b*=60 cm, 285 mrad,

Multiparticle simulation: 2012 LHC 5 106 turns, 10, 000 particles: b*=60 cm, 285 mrad, Np=1. 6 E 11, 50 ns spacing, 4 Te. V * probably underestimated by a factor 2 due to constant strong beam A. Valishev, HL-LHC beam-beam 30 Oct. 2013 t. L=36 hours - OK* 20

Work plan • Code consolidation • Old Baseline (b*=15 cm, q=590 mrad, leveling with

Work plan • Code consolidation • Old Baseline (b*=15 cm, q=590 mrad, leveling with CC) • Baseline HL-LHC (round optics, q=590 mrad, CC fully on, leveling with b*) • Plan B (Flat optics, BBLR, leveling with b*) 30 Oct. 2013 • Plan B with Crab Kiss A. Valishev, HL-LHC beam-beam 21

Work plan: code consolidation / development • Six. Track/Lifetrac • create simplified test case:

Work plan: code consolidation / development • Six. Track/Lifetrac • create simplified test case: turn off all long-range, perform intensity scan • verify CC in Six. Track • verify BB wire in Six. Track • Simulations vs. Run 1 data • collect data for a number of “good” high luminosity fills in 2012 • luminosity, intensity, bunch length, transverse emittances for b 1 & b 2 • calculate non-luminous luminosity, intensity and emittance lifetimes • subtract IBS, gas lifetimes from actual data • simulate DA and luminosity evolution for these fills 30 Oct. 2013 • bunch-by-bunch orbits • fix the code A. Valishev, HL-LHC beam-beam 22

Work plan: Old Baseline • Simulate: DA, Luminosity lifetime • Break points along fill

Work plan: Old Baseline • Simulate: DA, Luminosity lifetime • Break points along fill 1 Np=2. 2 E 11, crab off ü DA ok ü Lumi lifetime NOT OK : 12. 5 hours 2 Np=? ? , crab=50% ? DA ? Lumi lifetime 3 Np=0. 95 E 11, crab=100% 30 Oct. 2013 ? DA ? Lumi lifetime A. Valishev, HL-LHC beam-beam 23

Work plan: Baseline • Simulate: DA, Luminosity lifetime • Break points along fill 1

Work plan: Baseline • Simulate: DA, Luminosity lifetime • Break points along fill 1 Np=2. 2 E 11, b*=70 m ü DA ok with b*=40 m ü Lumi lifetime ok 2 Np=? ? , b*=? ? DA ? Lumi lifetime 3 Np=0. 95 E 11, b*=15 cm 30 Oct. 2013 ü DA ok ? Lumi lifetime A. Valishev, HL-LHC beam-beam 24

Work plan: Plan B • So far for this option we only established the

Work plan: Plan B • So far for this option we only established the minimum required crossing angle without bb wire to achieve DA • Need to implement and optimize bb wire • Leveling with b*, keeping constant b 1/b 2 ratio 30 Oct. 2013 • Need a number of break-points along fill A. Valishev, HL-LHC beam-beam 25

Work plan: Plan B with Crab Kiss • First results were obtained with CK

Work plan: Plan B with Crab Kiss • First results were obtained with CK in crossing plane • Need to implement CC in parallel sep. plane in flat optics • Leveling with b*, keeping constant b 1/b 2 ratio or CK? 30 Oct. 2013 • Need a number of break-points along fill A. Valishev, HL-LHC beam-beam 26