the lhc startup

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

SQM 2008 中国·北京 · 清华大学 2008 年 10 月安飞德意大利国家核物理学院（帕多瓦）

33

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 ……


44

55

ALICE

ATLAS

CMS

LHCb


66

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


77


88

ATLASATLAS


99

CMSCMS


1010

Cosmics (ATLAS)Cosmics (ATLAS)


1111

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)


1212

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)


1313

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)


1414


1515

16

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%)

SQM 2008 中国 · 北京 · 清华大学 2008 年 10 月安飞德

意大利国家核物理学院（帕多瓦）

ALICE TPCALICE TPC


1717

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


1818

Extraction tests: 14-15 JuneExtraction tests: 14-15 June


1919

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 ! !


2020

Optics: measured vs theoreticalOptics: measured vs theoretical

kick response (histo = measured, points = model)kick response (histo = measured, points = model)


2121

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)


2222

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)


2323

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


2424

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)


2525

run 58338run 58338event 27event 27

Beam-halo event in ATLASBeam-halo event in ATLAS

2626SQM 2008 SQM 2008 中国中国 ··北京北京 · · 清华大学清华大学 20082008 年年 1010 月安飞德意大利国家核物理学院（帕多月安飞德意大利国家核物理学院（帕多瓦）瓦）

Trigger TimingTrigger Timing

Measurements of relative arrival times of trigger signals Measurements of relative arrival times of trigger signals


2727

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


2828

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


2929

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


3030

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 ……


3131

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


3232

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” ??? ……


3333

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 !


3434

谢谢 !


3535


3636

the lhc startup

Documents