Slide 1

Frontier High Energy AcceleratorsHermann Schmickler -CERN

Tuesday, 27th September 2011

JOINT ISTC-CERN-JINR SUMMER SCHOOL ON HIGH ENERGY PHYSICS AND ACCELERATOR PHYSICS

1Today: Overview of frontier accelerators the LHC and upgrades Tomorrow:The next possible e+e- linear colliderAccelerator Controls

3TrendsofHEPfacilities

Towards Luminosity frontierTowards Energy frontierCourtesy of M.BiscariEPS-HEP09HadronsX10 /11yHadronsX10 /27yLeptonsX10 /17yLeptonsX10 /33yX10 / 8.5yLuminosity factoriesEnergy frontier 4Present HEP colliders at Energy/Luminosity frontiers5

ProtonsLeptonsB Factoriese-/HadronIons6

LHC/Tevatron lum. = 20LHC/Tevatron energy = 14HL-LHC/LHC luminosity = 5HE-LHC/LHC energy = 2.4 The LHCOverviewParametersCritical ComponentsDipolesInsertionsCollimationBeam Dump

Key featuresProtons and Ions450 GeV to 7 TeVHigh luminosity: Many bunches: 2808 bunches per beamHigh beam currents Small beam size at the interaction pointsTwo rings:Got to keep the beam apart2 in 1 dipole designLEP tunnel: reuse B 8.4 THigh field: Superconducting magnets for the most part with dipoles and lattice quadrupoles working at 1.9 K superfluid helium (30 kTons cold mass; 90 Tons of Helium)

Two high luminosity experimentsTwo more specialised experiments (Ions and b physics) lower luminosityWe want to produce high luminosity at high energy so we can discover the Higgs, supersymmetry and other exciting stuff.

Layout - insertionsPoint 1Atlas, big, high luminosity experimentPoint 2Alice, little less big, heavy ion experimentInjectionPoint 3Momentum cleaningPoint 4RFPoint 5 CMS, another big, high luminosity experimentPoint 6 Beam DumpPoint 7Betatron cleaningPoint 8LHCb, experiment, B physicsinjection

Atlas

CMS

Alice

LHCb

Actors: before beam Cryogenics Vacuum Quench Protection System Magnets Magnet protection system Interlocks Access Technical services: cooling, ventilation, electricity, safety Radiation protection

More-or-less going to assume that this lot is working

Actors: with beamPower convertersRF transverse damper400 MHz (& LFB)CollimatorsTDIBeam DumpKickersBeam InstrumentationMultipole FactoryInterface to cryogenics & vacuumInterface to experimentsControl System

16Lets bend the beamMomentum at collision 7 TeV / cMomentum at injection 450 GeV / cMachine Circumference 26658.883 mRevolution frequency 11.245 kHzSuper-periodicity 1 Lattice Type FODO, 2-in-1 Number of lattice cells per arc 23

Number of dipoles1232Dipole field at 450 GeV 0.535 TDipole field at 7 TeV 8.33 TBending radius 2803.95 mMain Dipole Length 14.3 mConcrete Numbers

1232 magnets to get us round in a circleLHC - dipole

LHC - quadrupole

Two intersecting ellipses, rotated by 90, generate perfect quadrupole fields

The Arc BPM - SSS LayoutFODO optics

Insertion

Clearly we have to collide the beamsAnd then get the beam sizes at the interaction point as small as possible * = 0.5 m = 5 x 10-10 m * = 16 m

Lot of energy out there...High energy, high intensity beam: energy per beam up to 0.35 GJOr 102 kg TNT

Huge amount of energy in the magnetsStored magnetic energy up to 1.29 GJ per sector

Energy has got to be extracted in case of a quench otherwise we end up with scrap metal.

Two very cold, very dark, very small holes...One guy in a Subaru going at 1600 mphOne girl in a Porsche doing 6700 mphBaseline cycle

In the normal operations the LHC will perform a standard cycle which will be more-or-less set in stone.

At less than 1% of nominal intensity LHC enters new territory.There is no easy start-up for collimation!

The LHC Challenge for CollimationHigh stored beam energy~ 350 MJ/beam(melt 500 kg Cu, required for 1034 cm-2 s-1 luminosity)

Small spot sizes at high energy200 mm (at coll.)(small 7 TeV emittance, no large beta in restricted space)

Large transverse energy density1 GJ/mm2(beam is destructive, 3 orders beyond Tevatron/HERA)

High required cleaning efficiency99.998 % (~ 10-5)(clean lost protons to avoid SC magnet quenches)

Collimation close to beam6-7 s(available mechanical aperture is at ~10 s)

Small collimator gap~ 3 mm (at 7 TeV)(impedance problem, tight tolerances: ~ 10 mm)

Activation of collimation insertions~ 1-15 mSv/h(good reliability required, very restricted access)

Big system60 coll / 2 insertions

Basic Collimation

Beam core Primary beam halo to 6 generated by non-linearities (beam-beam) noise Secondary beam halo 6 to 8 generated by primary collimator Tertiary beam halo: > 8 generated by secondary halo harmless lossesCollimatorsTwo warm LHC insertions dedicated to cleaning:

IR3Momentum cleaning1 primary6 secondary

IR7Betatron cleaning4 primary16 secondary

Two-stage collimation system54 movable collimators for high efficiency cleaning, two jaws each + other absorbers for high amplitude protectionStrategy:

Primary collimators are closest.

Secondary collimators are next.

Absorbers for protection just outside secondary halo before cold aperture.

Relies on good know-ledge and control of orbit around the ring!Recent timeline 2008Accelerator completeRing cold and under vacuumSeptember 10th 2008First beams around made it to GoogleSeptember 19th 2008The incident2008 200914 months of major repairs and consolidationNew Quench Protection System for online monitoring and protection of all joints.However

Magnet Interconnection

Dipole busbar

Melted by arc33To go to 7 TeV per beam

Everywhere

Splice consolidation is required - options under examination

To conclude on this issueSplice issues not fully resolvedTo be 100% sure that we can go safely to 7 TeV per beam - eradication of joint issue requires a complete warm-up and long shutdown (2013).The LHC beam energy will be limited to 3.5 TeV in 2010/2011/2012

New Quench Protection System fully deployed and tested All magnet circuits qualified for 3.5 TeVMain bends and quads to 6000 A and looking good so far

In the meantimeBeam dumpBeam dumping systems working very wellSystematic and very thorough testing and set-up in progress

Kickers sweep bunches to dilute intensity on dumpBeam InstrumentationBeam Position MonitorsExcellent performance Very stable orbit (V drift ~ 15m/h)Beam Loss MonitorsBLMs correctly removes the BEAM PERMIT signal if measurements are over threshold. Almost no reliability issues observed.Profile monitorsSynchrotron light, wire-scanners operational

Base-Band-Tune (BBQ) system was a work horse from day one giving tune, chromaticity, coupling, feedback.

The enabler excellentMachine Protection SystemMission critical backboneBeam Interlock SystemSafe Machine ParametersPlus inputs to/from other systems (e.g. timing, BCT)Multitude of user inputsIn additions the beam drives a subtle interplay of:Beam dump system, Collimation, protection devices, RFInstrumentation (BLMs, BCT, BPMs)ApertureOpticsProvides the mechanism to dump the beam in around 3 turns if anything out there decides its had enoughAbsolutely, absolutely criticalRamp

Energy: 450 to 3500 GeV Main bend current: 760 to 5850 A Ramp rate: 2 A/s Length: 47 minutes7 e9450 GeV3.5 TeVHL-LHC LHC modifications

Booster energy upgrade1.4 2 GeV, ~2015Linac4, ~2015SPS enhancements(anti e-cloud coating,RF, impedance), 2012-2021IR upgrade(detectors,low-b quads,crab cavities, etc) ~2020-2140HE-LHC LHC modifications

2-GeV BoosterLinac4SPS+,1.3 TeV, 2030-33HE-LHC 2030-3341IssuesHigh Luminosity LHCHigh energy LHCSuper-Cond. quadrupoles15 T for low beta @IRfor IR and RingSuper-Conducting dipoles20 T (Nb3Sbn, HTS)Fast cycling SC magnetsFor 1.3 TeV injectorMini beta operationChromatic correction and large aperture of matching sectionCryogenic handling of SR heat loadCrab cavitiesNovel compact design compatible with machine protectionMachine protection (500 MJ beam power)Collimation with high effic, & reliability, low impedanceCryogenic handling of SR heat loadLuminosity levelingControl qc , Vcrab or b*Control emittancesDynamic vacuumSynchrotron radiation42LHC upgrade issues and R&D

Super-ConductinHIGH FIELD MAGNETSHL-LHC:L = 5 1034LHC upgradesHE-LHC: Ecm = 33 TeVLow b quads(15T)Dipoles (20T)

15 to 24 T Possible Super-conductors: Nb3Sn existing up to 17-18 T High Temperature SC : Bi-2212 (existing) or YBCO (small tapes only)

Promising but lots of R&DHigh Field Super-Conducting magnet R&D43

Chart18.337398.337840.4329190.43211440.5331266.73131125640.5331457.11489300520.57226277372370.44187956560.67080291973856.2468418740.835036496441100.92462139515848.07529453241.06358751317848.07529453241.73024954719848.07529453242.814778716710848.07529453243114124.26866809825.72852211287.18837612747.91830313478.32992700738.33

Preinjection plateauRamp downStart rampInjectionBeam dumpPhysicsPreparePhysicsTime [s]MB currentB [T]

Sheet1B MBcurrent MBenergyKQFMQMMQYInjection plateau0alpha0.0000060893current rate end snapback0.6current at injection739-30008.33114127current variation during snapback20-26018.33114127parabolic segment duration3.42E+02-15200.4326000.3650.0089570.00653140.0045236current at end exp4.11E+03-9200.4326000.365b at end exp3-9000.5337390.4513.44current to field scaling factor1.37E+0300.5337390.4513.449.86.79max current rate101005.72E-017840.482983348514.4310.527.29current rate end parablolic3.08E+002006.71E-019190.56576364316.912.338.54exp time constant inverse2.43E-033008.35E-0111440.703730800421.0315.3310.623.42E+029.25E-011.27E+030.7789880923.2716.9711.75exp duration4.84E+024001.06E+001.46E+030.895728897226.7619.5113.526001.73E+002.37E+031.455769466943.4931.7221.978002.81E+003.86E+032.366846299170.7151.5635.718.26E+023.00E+004.11E+032.522444529975.3654.9538.0610004.27E+005.85E+033.5882103429107.278.1754.1412005.73E+007.85E+034.8145850762143.84104.8972.6514007.19E+009.85E+036.0409598095180.48131.6191.1515007.92E+001.08E+046.6541471761198.8144.97100.41.56E+038.33E+00114126.9999386813209.13152.5105.6220008.33114127krcs1krcs20.6363-1.481238.7716811207-555.7454969983714.2261507672-8644.929953302200.4326002000.43260012818.331141221818.331141223620.43260032620.43260032820.53373942820.533739

Sheet1

MBMQMQMMQYTime[s]B [T]B2 [T/m]Quad gradients in ramp

Sheet2

Preinjection plateauRamp downStart rampInjectionBeam dumpPhysicsPreparePhysicsTime [s]MB currentB [T]

Sheet3

TimeMB currentMB field

Ramp down( 18 Mins

Pre-Injection Plateau15 Mins

Injection( 15 Mins

Ramp( 28 Mins

Squeeze( 5 Mins

Prepare Physics( 10 Mins

Physics10 - 20 Hrs