Presentation on theme: "Highlights from the Large Hadron Collider"— Presentation transcript:
1 Highlights from the Large Hadron Collider Physics at the TerascaleThe LHC: brief overview and statusThe LHC experiments: brief overview and statusJos EngelenCERN
2 Standard Model and Beyond(?) x8gaugeHThe Higgs sector – ‘the unknown’The Supersymmetric world?One supersymmetric partner for each ‘standard’ particle –the Higgs sector becomes slightly more complicated: 5 supersymmetricHiggs bosons
3 The ‘Standard Model’is a wonderful model for describing the fundamentalparticles and fields and their interactions, it provides aquantitative description of all experimental results so far, but:the model invokes a mechanism for dealing with mass: it is anempirical fact that certain field particles (W, Z bosons) carry mass,incorporating this in the theory is highly non-trivial – it requiresthe introduction of a new field (Higgs field) and correspondingparticle (‘the Higgs’): this particle has never been foundby an experiment it will be at the LHCthe model would ‘go wrong’ at high energy without the Higgsparticle (or other ‘new physics’)‘unification of forces’ at very high energy could be revealed bya new trend setting in at LHC energy: ‘supersymmetry’
4 ‘The Terascale’ Based on ‘extrapolations’ from our present understanding and on quite general theoreticalinsights we expect the ‘new physics’ to manifestitself at an energy around or below1 Tera-electronVolt = electronVolt, i.e.at the Terascaleaccessible at the LHC for the first time(and only at the LHC for years to come!)
5 Quark Gluon Plasma The LHC will also provide Pb Pb collisions at TeVallowing unique contributions to the studyof a quark gluon plasma
6 Accelerator and Experiments Undergroundcircular tunnel27 km circum-ference; 100 munderground4 caverns forexperiments ()xCMSBDxxRF*xLHCbALICEATLAS
7 Accelerator Collisions of 7,000 GeV on 7,000 GeV protons (for reference: proton mass = 1 GeV)Luminosity 1034 cm-2s-1(collision rate normalized to cross section)Innovations: ‘2 in 1’ superconducting 8.3 T dipoles(operating temperature 1.9K)focusing s.c. quadrupolesChallenges: collimation (350 MJ stored energy perbeam, can melt 800 kg of copper)and furthermore the mere size of thesystem, e.g. more than 33,000 tonnesof ‘cold mass’, 27 km of cryogenicdistribution line, etc.
8 Accelerator complexBiggest ring = 27 km circumference(1959)
10 Van streng tot kabelNiTi filamenten, 7(geproduceerd viaextrusie)
11 In the tunnel Magnet inter- connect Quality control and Quality assurance
12 Magnet Interconnect6 superconducting bus bars 13 kA for B, QD, QF quadrupole20 superconducting bus bars 600 A for corrector magnets (minimise dipole field harmonics)To be connected:Beam tubesPipes for heliumCryostatThermal shieldsVacuum vesselSuperconductingcables13 kA Protection diode42 sc bus bars 600 A for corrector magnets (chromaticity, tune, etc….)+ 12 sc bus bars for 6 kA (special quadrupoles)
13 In the tunnel Jumper connecting cryogenic distribution line and magnets(once every~100 m)(early photo,tunnel practicallyempty)
14 In the tunnel Beam delivery towards interaction point Current distributionusingHigh TemperatureSupercondutorcurrent leads
15 LHC Status Installation complete Hardware commissioning cryogenic distribution lineinjection linessc dipoles and quadrupoles; interconnectinner triplets preparing beams for collisionRF stations (sc) for acceleration 450 GeV 7000 GeVbeam dumpscollimationbeam instrumentationHardware commissioningcool-down completepressure testspowering testsCommissioning with beamcirculating beamsColliding beamsRestart Spring 2009
16 Start of Operations The Large Hadron Collider project saw a wonderful start of operations on September 10, 2008:LINAC, Booster, PS, SPS were accelerating beam to450 GeV for injection into the LHCThe injection lines (TI8, TI2) transported the beamto the LHCThe injection kickers sent the beam(s) into the LHCCirculating beams, in both apertures, were establishedfor the first time, with the whole world looking overour shoulders, in a matter of hoursThe LHC experiments were ready and operational asplanned and recorded beam related (timing!) dataimmediatelyThe Worldwide LHC Computing Grid was up and running
17 Start of Operations During the days following September 10 some unreliable (‘old’) elements of the electricalinfrastructure (transformers) had to be repaired/replaced,but the preparations for collisions continued, one othervery important milestone was passed easily, not becauseit was easy but because of excellent preparations:the RF system captured the beamthe road to first beam-beam collisions was now fully open
18 Final Hardware Commissioning The magnets in Sector (‘Octant’) 34 had not beencommissioned yet to full current for operationat 5 TeV (i.e. commissioning to 5.5 TeV)The 7 other octants of the LHC had been commissionedto 5 TeV (and well above) without problemsOn September 19 (around 11:18) an incident occurred,leading to a large Helium leak in sector 34 – cold Heliumescaped into the tunnel, the insulation vacuum was broken(up to vacuum barriers), the beam vacuum was broken(up to sector valves)
19 Recovery Sector 34It is now clear that recovery of Sector 34 will takeuntil (‘into’) the planned (and obligatory) Wintershutdown – LHC operations will restart Spring 2009.A precise planning is being worked out.The nature of the incident has been understood– it is due to an electricalfault (resistive splice in interconnect)The loss of the insulation vacuum lead to some collateraldamage – the logistics of the repair program are beingworked out.Very importantly: diagnostic tools are being designed toavoid such problems in the future
20 Schedule of Experiments The experiments will now go into ‘long shutdown’ mode,to be ready again in early Spring 2009: a more precisedate will be agreed with them as soon as this is possibleMost experiments have identified a useful and/or necessaryprogram of work of 4 – 5 months: repairs, refurbishments,improvements, additional installation workEverybody involved in the LHC project is as motivated asever (or more motivated than ever) to overcome thistemporary setback! Everybody has reacted professionallyand with determination.
21 The successful start-up The behaviorof the beams was excellent and understood
26 The RF cavities and transverse dampers Preparation for BeamRF synchronization in place – clocks and timing now going from SR4 to all users. Recent successful dry run tests with all users and OP group, including basic software.Procedures for beam commissioning well defined.Longitudinal diagnostics in good shape to study and commission first beams….Fibre-optics signal distribution from RF in SR4 to Experiments, BT & BI equipment and to CCC.40 MHz bunch clocks, revolution frequencies,40 MHz 7TeV reference. Injection & dump kicker pulsesCourtesy Edmond Ciapala
29 08 08 08 Friday 15:20 Beam on to TI2 TED MSI etc pulsing Cycle LHC Sector 23OPBeam down TI2 first shotFriday 19:00TI2 TED out, beam to TDI, kickers offGive Alice 20 minute warning before taking TED outINJBeam on TDI after correction end TI2Friday 21:00Kickers on, time in, position checksResolve timing issuesInteresting collaboration between timing and RFFriday 21:40TDI out - threading - momentum matching - beam to IR3Jorg & teamBeam to IR3 first shot. Tweak SPS.Courtesy Roger Bailey
32 Dispersion 2-3The trajectory of the off-momentum (1 per mil) beam. On the farleft is the end of TI2 where there are no measurements. It goesthrough LSS2 and Alice with practically zero dispersion. In the arcthere is a slight mismatch which is of no consequence and LSS3 itperfectly maps the large dispersion bump from positive to negativethat is designed to stop uncaptured particles (which will be lost as thefield rises since they are not accelerated) on the collimators.The vertical dispersion (bottom) is zero as it should be.
41 Injection tests SPD hits versus bunch intensity (beam through ALICE) FMD event display(1 bunch through ALICE, > hits)FMD hits versus SPD hits(beam through ALICE)SPD/SSD, Sunday, 15.6Dump on TED
42 Luminosity monitor (V0) Double turn, beam 1 back at point 2 !Single turn
43 Auto-correlation for SPD trigger, with multi-turn correlations Beam pick-upT0SPDV0Auto-correlation for SPD trigger,with multi-turn correlations(3564 bunch crossings)Trigger timing (before alignment) versus bunch numbersingle shotfor SPD, V0, beam-pickup BPTX, T0 triggers
44 First interactions 12th September Circulating beam 2stray particle causing an interaction in the ITSITS tracks on
45 Krypton Gain Calibration TPCParticleIdentificationKrypton Gain CalibrationMomentumResolution24/10/ rd RRB J. Schukraft
46 LHCb Spectrometer OT Muon System Magnet RICH1 VELO RICH2 TT Calo. System
47 LHCb sees tracks from the LHC injection tests SPD (provided trigger)TED eventsLHCb sees tracks from the LHC injection testsMuon chambersVELO(Run 30933, Event 14)Silicon tracker
48 Beam1 induced OT tracks originating close to the beam pipe
49 ATLAS 45 m 24 m 7000 Tons Status of ATLAS ATLAS superimposed to the 5 floors of building 4024 m7000 TonsStatus of ATLASLHCC, 24-Sep-2008, PJ
50 Very first beam-splash event seen in ATLAS (as seen online in the ATLAS Control Room) on 10-Sep-2008 at 10:19
51 A busy beam-halo event with tracks bent in the Toroids from the start-up day (offline)
52 TRT in the run 22-25 August (a cosmic shower) Barrel-tracksShower
54 Calorimeters: Collimators Closed Energy in ECAL (EE-, EB, EE+)ECAL: Splash events provided a source for overall internal synchronization.Crystals were time aligned to within 1ns !
55 WLCGSince CCRC08 in May the experiments have continued to run work at very high levels on the grid infrastructure and continued to keep data transfers running at a level consistent with that expected in data taking. WLCG has seen cosmic data and also the first “events” from LHCb during the second injection test, and data sets from all 4 experiments on Wednesday 9/10. The transfer rates all summer have been in excess of 1 GB/s more or less continuously with higher peaks (the data taking rate is 650 MB/s, twice that for safety). This, and the continuous high rate of job submission has been driven by experiment functional testing, and more and more detector-driven stress tests.
56 ConclusionsThe LHC experiments have followedthe remarkable performance of theLHC machine with an equally remarkableperformance:the detectors work with real beam!
57 ConclusionsRecovery of Sector 34 has the highest priorityStart-up in Spring 2009 is now the targetAnd then: a two phased approach to SLHC
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