the lhc startup
DESCRIPTION
The LHC Startup. Federico Antinori INFN, Padova , Italy and CERN, Geneva, Switzerland. Since you asked…. So: what happened on 19 Sept ?. 19 September, ~ 11:30: large helium leak in sector 34 helium escaped in the tunnel insulation vacuum broken beam vacuum broken (up to sector valves) - PowerPoint PPT PresentationTRANSCRIPT
TheThe LHC StartupLHC Startup
Federico AntinoriFederico Antinori
INFN, Padova, ItalyINFN, Padova, Italy
andand
CERN, Geneva, SwitzerlandCERN, Geneva, Switzerland
Since you asked…Since you asked…
So: what happenedSo: what happened on 19 Sept?on 19 Sept?
19 September, ~ 11:30: large helium leak in sector 3419 September, ~ 11:30: large helium leak in sector 34 helium escaped in the tunnelhelium escaped in the tunnel insulation vacuum brokeninsulation vacuum broken beam vacuum broken (up to sector valves)beam vacuum broken (up to sector valves)
probably due to electrical fault probably due to electrical fault resistive splice in interconnect?resistive splice in interconnect?
to be sure, have to wait for interconnect to be opened (at room to be sure, have to wait for interconnect to be opened (at room T)T)
magnets in sector 34 were being commissioned to 5 TeVmagnets in sector 34 were being commissioned to 5 TeV all other (7) sectors had been commissioned to 5 TeV (and above) all other (7) sectors had been commissioned to 5 TeV (and above)
without problemswithout problems
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When will beam resume?When will beam resume?
clear that recovery of sector 34 will take until into the winter clear that recovery of sector 34 will take until into the winter shutdownshutdown
LHC operations are planned to restart in springLHC operations are planned to restart in spring precise planning being worked outprecise planning being worked out
experiments now going into shutdown modeexperiments now going into shutdown mode repairsrepairs improvementsimprovements additional installationsadditional installations ……
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ALICE
ATLAS
CMS
LHCb
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Large Hadron Collider (LHC)Large Hadron Collider (LHC)
about 100 m undergroundabout 100 m underground 27 km circumference27 km circumference
11245 orbits per second 11245 orbits per second pp collisions up to √s = 14 TeVpp collisions up to √s = 14 TeV Pb-Pb collisions up to Pb-Pb collisions up to √s√sNNNN = = 5.5 TeV5.5 TeV
ALICEALICE
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ATLASATLAS
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CMSCMS
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Cosmics (ATLAS)Cosmics (ATLAS)
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Alignment of the ALICE ITSAlignment of the ALICE ITS
2200 volumes 2200 volumes 13k degrees of freedom 13k degrees of freedom Millepede, “hierarchical” alignmentMillepede, “hierarchical” alignment
~ 50 k cosmic events (SPD trigger ~ 0.1 Hz)~ 50 k cosmic events (SPD trigger ~ 0.1 Hz)
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Hit distribution in the 6 layers of the ITS
Distance between Distance between upper and lower upper and lower track segmentstrack segments
= 56 µm= 56 µm (40 µm in simulation (40 µm in simulation
with no misalignment) with no misalignment)
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after alignment
before alignment
after alignment
before alignment
Distance between hit Distance between hit and track in the and track in the overlap regionoverlap region
= 22µm= 22µm (15 µm µm in simulation (15 µm µm in simulation
with no with no misalignment)misalignment)
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Particle shower in the endcapParticle shower in the endcap
ShowerShower
Cosmics showers/interactions in the TRT with solenoid on
Fully commissioned and inside ATLAS partition since long
(Xe is in since few days results shown are with Ar/CO2/O2; 70/27/3%)
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ALICE TPCALICE TPC
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Cosmics Laser Krypton
ExB
vdrift
Particles in the LHCParticles in the LHC
first signs of life…first signs of life… 14-15 June14-15 June extraction in TI2 and dumpextraction in TI2 and dump
injection tests injection tests 1)1) 8-11 August8-11 August
first injection in LHC (beam 1)first injection in LHC (beam 1)
2)2) 22-24 August22-24 August first injection of beam 2first injection of beam 2
3)3) 5-7 September5-7 September
circulating beamscirculating beams 10 September10 September
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Extraction tests: 14-15 JuneExtraction tests: 14-15 June
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14 June 15 June
ALICE Pixels
beam extracted from beam extracted from the SPS and dumped in the SPS and dumped in the transfer linethe transfer line
muons make it all the muons make it all the way to ALICEway to ALICE
08.08.0808.08.08 :: First Injection in LHCFirst Injection in LHC ! !
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Optics: measured vs theoreticalOptics: measured vs theoretical
kick response (histo = measured, points = model)kick response (histo = measured, points = model)
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First injection in the LHC!First injection in the LHC!
8 August 20088 August 2008 ALICE SPD (pixel) and V0 ALICE SPD (pixel) and V0
(scintillator) switched on (scintillator) switched on during first phase (upstream during first phase (upstream dump)dump) pilot bunches: ~ 5 10pilot bunches: ~ 5 1099 protons protons
Trigger: ≥ 10 hits on layer 2Trigger: ≥ 10 hits on layer 2 32 events triggered 32 events triggered
Run 51403 (16:53 to 18:05)Run 51403 (16:53 to 18:05)
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multiplicity
SPDSPD
V0 vs SPDV0 vs SPD
ADC vs multiplicity
Δt
Background studiesBackground studies bunches of 2 10bunches of 2 1099 protons injected through ALICE from TI2 protons injected through ALICE from TI2
all beam screens in all beam screens in ~ 100 particles per cm ~ 100 particles per cm22 in ALICE (inner region) in ALICE (inner region) LHC ring screens out, injection line screens in LHC ring screens out, injection line screens in 1-2 part. per cm 1-2 part. per cm22
all screens out all screens out no detectable background (SPD triggers: only cosmics) no detectable background (SPD triggers: only cosmics)
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10 September: circulating beams!10 September: circulating beams!
beam 1: 1beam 1: 1stst complete orbit ~ 10:30 complete orbit ~ 10:30
beam 2: 1beam 2: 1st st complete orbit ~ 15:00complete orbit ~ 15:00
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first signals from ALICEfirst signals from ALICE
11 September: RF capture11 September: RF capture(Physics data!)(Physics data!)
11 September, ~ 22:35 first capture11 September, ~ 22:35 first capture beam 2 kept in orbit for over 10 minutes! beam 2 kept in orbit for over 10 minutes!
series of injections with tens of mins RF capture during series of injections with tens of mins RF capture during nightnight in ALICE: 673 events in totalin ALICE: 673 events in total
first data for Physics (beam 2 background)first data for Physics (beam 2 background)
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run 58338run 58338event 27event 27
Beam-halo event in ATLASBeam-halo event in ATLAS
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Trigger TimingTrigger Timing
Measurements of relative arrival times of trigger signals Measurements of relative arrival times of trigger signals
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ALICEALICEATLASATLAS
Beam-halo in CMS CalorimetersBeam-halo in CMS Calorimeters
Correlation between hadronic Correlation between hadronic and electromagnetic energyand electromagnetic energy
Crystals were time-aligned to ~ Crystals were time-aligned to ~ nsns
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Next: first collisions (2009)Next: first collisions (2009)
e.g.: 2 on 2 bunches with one delayed bunch per beame.g.: 2 on 2 bunches with one delayed bunch per beam
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delayed by 75ns
with this scheme, for each with this scheme, for each orbit, each experiment sees:orbit, each experiment sees: 1 beam-beam encounter1 beam-beam encounter 1 beam-gas encounter1 beam-gas encounter 1 gas-beam encounter1 gas-beam encounter
First collisions @ 900 GeVFirst collisions @ 900 GeV 1 beam-beam bc per orbit1 beam-beam bc per orbit * = 10 m* = 10 m beam size = 280 µm (beam size = 280 µm ()) L ~ several 10L ~ several 102727 cm cm-2-2 s s-1-1
rate per bc ~ a few %rate per bc ~ a few % MB rate ~ a few 100 HzMB rate ~ a few 100 Hz
First PhysicsFirst Physics
average multiplicityaverage multiplicity multiplicity distributionmultiplicity distribution
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10 TeV|| < 0.9
ppTT distribution distribution
ppTT distr. vs mult’y distr. vs mult’y
ppTT distr. for identified distr. for identified particlesparticles
strangeness productionstrangeness production baryon transportbaryon transport ……
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CDF, Phys. Rev. D65 (2002) 072005
charged multiplicity
<p
T>
(G
eV/c
)
Before long: hard physicsBefore long: hard physics
e.g.: e.g.: DD00 K K--++
forfor LL > 10> 102828 cm cm-2-2ss-1-1
(1 bc per orbit @ 10 (1 bc per orbit @ 10 TeV)TeV)
~ 3 10~ 3 1077 events/day events/day
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High multiplicity pp!High multiplicity pp!
As soon as As soon as LL ~ 10 ~ 103030 cm-2s-1 cm-2s-1
high multiplicity trigger!high multiplicity trigger! e.g.: 10 x mean e.g.: 10 x mean dNch/dy ~ 50 dNch/dy ~ 50 ~ semi-central Cu-Cu @ RHIC ! ~ semi-central Cu-Cu @ RHIC !
““heavy-ion physics” in pp ? heavy-ion physics” in pp ? strangeness enhancement ?strangeness enhancement ? transverse flow ?transverse flow ? HBT ?HBT ? v2 ??v2 ?? ““Rcp” ???Rcp” ??? ……
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Phobos Cu-Cu
ConclusionsConclusions
2008 was a crucial year for LHC2008 was a crucial year for LHC completion of installationscompletion of installations checkout/commissioning of machinecheckout/commissioning of machine commissioning of experimentscommissioning of experiments
individual subdetectorsindividual subdetectors system-level operationsystem-level operation organization of human operationsorganization of human operations
first beams !first beams ! background studiesbackground studies timingtiming calibrationscalibrations machine opticsmachine optics
looking forward to continuing the adventure after the looking forward to continuing the adventure after the winter shutdown !winter shutdown !
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谢谢 !
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