The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.

Status of Task2.2 HL-LHC Optics and Lattice

Bernhard Holzer for the WP2, Task2.2 Team

R. De Maria, S. Fartoukh CERN, Geneva, Switzerland,A. Chancé, B. Dalena, J. Payet, CEA, Gif sur Ivette, France,

A. Bogomyagkov, BINP SB RAS, Novosibirsk, RussiaR. B. Appleby, S. Kelly, M. B. Thomas, The University of Manchester, UK,

L. Thompson, The University of Manchester and the Cockcroft Institute, UK, M. Korostelev, K. M. Hock, A. Wolski, University of Liverpool and Cockcroft Institute, UK,

C. Milardi, INFN, Frascati, Italy,A. Faus-Golfe, J. Resta Lopez, IFIC (CSIC-UV), Valencia, Spain

Luminosity & Beam Optics

Goal: establish & optimise a lattice that is adequate for the luminosity envisaged for the HL-LHCMatch a full set of beam optics that corresponds to the experiment desiderata

Baseline Version: 150mm triplet aperture

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Status: the V1.0 Baseline Optics

/afs/cern.ch/eng/lhc/optics/HLLHCV1.0... which is clearly the 150mm version

for details: MADX sample job (RdM)It contains short cuts ...to the LHC standard optics & lattice (Version V6.503, or called “db5” in the sample job).to the LHC upgrade optics and lattice HLLHCV1.0, or called slhc in the sample job.

D2 Q5

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Status: the V1.0 Lattice

The upgrade lattice used here differs from the LHC standard by:A new triplet with 2 quadrupoles per triplet lens,A s.c. D1 magnet,A shift in D2 by 15m towards the IP, to gain the space needed for the crab cavitiesA shift of the position of the Q5 by 11m towards the arc to optimise the optics flexibility with a change of the type from MQML to a new proposed MQYL typeA small shift of Q4,An additional sextupole in Q10 for IR1&5The 3 crab cavities per side and beam, IR1&5A new Q5 in IR6 of the MQYL typeA new set of corrector package including a5,b5,a6New orbit correctors in the triplet and D2

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The V1.0 Optics

ATS Luminosity base line case:round at βx*=15cm, file=”slhc/opt_round.madx”this is our standard optics, 15cm beta in both planes.the β* in IP2,5 is 10m and 3m respectively (round beams) ATS Luminosity alternatives:round at βx*=10cm, file=”slhc/opt_sround.madx”flat at βx*=30cm, ,βy*=7.5cm file=”slhc/opt_flathv.madx”super flat, βx*=5, βy*=20cm, file=”slhc/opt_sflat.madx”super flat, βx*=20, βy*=5cm, file=”slhc/opt_sflathv.madx”

Injection optics:injection ... version 18m: file=”opt_inj_18m.madx"injection ... version 11m: file=”opt_inj_11m.madx"injection ... version 6m: file=”opt_inj.madx"

Our standard injection case is still the last in the list, resulting in βx,y*= 6m beta in IP1,5. In all injection files the beta at IP2,8 is put to 10m

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The V1.0 Optics

Pre-Squeeze optics:two different versions are available: the final pre-squeeze optics:

file=”opt_presqueeze.madx", referring to βx,y*= 0.44m at IP1,5and a pre-pre-squeeze with βx,y*=3.4m

file=”opt_presqueeze_3400.madx", with ATS phase advances.Then there is a file, that describes the optics at the end of the ramp

it refers to βx,y*=6.0mfile=”opt_endoframp.madx".

Finally the version for ion operation:Ions

Optics with IP15 at βx,y*=0.44m, IP2 and IP8 at βx,y*=50cmfile=”opt_presqueeze_3400.madx"

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Special Remarks: Fringe Fields

nominal LHC, 70mm aperture HL-LHC, 150mm aperture

known, but not yet compensated for in te v1.0 data base optics

improving the hard edge model by adding short lenses tomodel the fringe field effect.

court. Luke, Sam, Mathew

the “ATS Squeece Optics (15cm/15cm/10m/3m)

Serious Optics changes in the matching section ... But no Lattice Changes foreseen so far.

Special Remarks: HL-LHC Optics in IR2 / IR8

IP8

court. A. Bogomyagkov

IP2

Study of additional quadrupoles at Q5 / Q6 / Q7 ...

Q4 / Q5 / Q6 in triplet configuration & add. Q7 ... allows for much larger βs at the Crab Cavities

add. Quad at Q5: no big change

Lattice Optimisation for Crab Cavitiescourt. B. Dalena

* F

F

Provide Space for Crab Installation-> D2 shift

-> optimise latticeQ4,5,6 in “triplet configuration”

-> optimise optics

HL-LHC lattice, V1.0

HL-LHC lattice, Crab Optimised

LHC Standard Lattice

Special Remarks: Optimisation for Crab Cavities

Special Remarks: Optics Transitionsfrom injection to pre-squeeze, court. Maxim

avoid changes in gradient directionrunning at very low / very high gradientszero crossings (except trim quads)strong differences in the two apertures

keep the resulting beta beat as low as possible

all curves checked by magnet experts (Per Hagen / Ezio Todesco)

-> ok

Special Remarks: Optics Transitionsfrom injection to pre-squeeze

Optics Transition 6m -> 44cm in 19 steps

Δβ/β ≤ 3.7 %

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Some Remarks:

... concerning the additional options and efforts that go beyond these baseline optics: Robs and Barbara optimisations, using a triplet like structure in Q4, Q5, Q6 are

modifications on top of the lattice (V1.0) that we refer to here.Especially the option of adding a second Q7 to gain margin for the crab cavity voltage is NOT included in this lattice.

Anton’s optimisation of the IR2 & IR8 optics refer to the study of the phase advance for

ALL the HLLHC IR2 and IR8 optics mentioned here. Maxime’s interpolation optics refer to the HLLHC standard injection to pre-squeeze optics

mentioned here. The fringe field calculations from Rob/Luke/Sam/Mathew et al refer to this lattice and

optics (15cm) but we will need them for fine tuning of any of the optics in the context of the upgrade -> script in MADX. The effect is not rematched yet in V1.0.

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IPAC2013 was defined in task2.2 as a deadline to converge the efforts of the different team colleagues.

Still there might be room for further detailed modifications.

However we would like to freeze the status, including the complete set of optimised beam optics to pass hand over to task 2.3 for field specifications and tolerances.

To be determined:Options to improve crab cavity situation, but require additional hardware (Q7)

Conclusion:

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Magnet LHC SLHC V3.1b HL-LHC V1.0

triplet layout standard machine 140T/m, 150mm

MQXA 22.2...26.2m

MQXB 31.8...34.8m

MQXB 38.3...41.3m

MQXA 46.8...50.2m

MBXW D1 59...83m, 6 magnets

MBRC D2 152.1...157.9m

MQY Q4 167.7...169.6m

MQML Q5 194.0...196.5m

MQML Q6 225.9...228.4m

MQM Q7A 259.6...261.7

MQM Q7B 263.6...265.5

Lattice Modifications: Summary

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Lattice Modifications: SummaryMagnet LHC SLHC V3.1b HL-LHC V1.0

triplet layout standard machine 150T/m, 140mm 140T/m, 150mm

MQXA 22.2...26.2m MQXC 22.2...26.8m MQXC 1 22.2...25mMQXC 2 27.2...29.5m

MQXB 31.8...34.8m MQXD 33.6...37.5m MQXD 34.7...38.7m

MQXB 38.3...41.3m MQXD 42.2...46.0m MQXD 43.5...47.5m

MQXA 46.8...50.2m MQXC 52.5...56.7m MQXC 1 54.1...56.7mMQXC 2 58.9...61.2m

MBXW D1 59...83m, 6 magnets MBXA 68.6...72.8m, 1 magnet MBXA 71.2...76.0m, 1 magnet

MBRC D2 152.1...157.9m MBRD 137.5...142.9m MBRD 137.5...142.9m

MQY Q4 167.7...169.6m MQYY 167.7...169.6m MQYY 167.7...169.6m

MQML Q5 194.0...196.5m MQYL 205.0...207.5m MQYL 205.0...207.5m

MQML Q6 225.9...228.4m MQML 225.9...228.4m MQML 225.9...228.4m

MQM Q7A 259.6...261.7 MQM 259.6...261.7 MQM 259.6...261.7

MQM Q7B 263.6...265.5 MQM 263.6...265.5 MQM 263.6...265.5

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And finally B. Dalena et al:additional Quadrupole to support Q7

... crab cavitiy conditions

Magnet LHC Crab Cavity Story

triplet layout standard machine 170T/m, 120mm

MQXA 22.2...26.2m

MQXB 31.8...34.8m

MQXB 38.3...41.3m

MQXA 46.8...50.2m

MBXW D1 59...83m, 6 magnets

MBRC D2 152.1...157.9m

MQY Q4 167.7...169.6m MQYY ≈ 167.9

MQML Q5 194.0...196.5m MQYL ≈ 193.4m

MQML Q6 225.9...228.4m MQML ≈ 220.3m

MQML7 ≈ 248.9...253.7m

MQM Q7A 259.6...261.7 MQM ≈ 260

MQM Q7B 263.6...265.5 MQM ≈ 263.7

Lattice Modifications: Summary

Lattice & Crab Cavities: Beam Orbit

Standard Bump for Crossing angle & beam separation closes at Q5 ... and leads to (varying) orbit offsets at the crab cavity location.-> bump closure by strong dipole magnet at D2.-> Alternative: transverse cavity positioning feedback following the beam orbits

court. R. DeMaria

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€

Bdl = 6Tm / 1Tm∫

A. Dexter/ E. Jensen Frascati Workshop 2012

strong orbit corrector needed in front of D2 for crossing angle bump & separation bumpfirst estimates:

Lattice & Crab Cavities: Beam Orbit