The ALICE Experiment at the CERN LHC
P. Kuijer
for the Alice collaboration
ICHEP 2002
ICHEP, 27-7-2002 P. Kuijer 2
SPS-RHIC-LHC
Hotter, bigger and longer life time at higher energies:
Alice: properties of QGP well above threshold
PbPb central SPS RHIC LHC
dNch/dy 500 700-1500 2000-8000e [GeV/fm3] 2.5 3.5-7.5 15-40
Vf [fm3] 103 7*103 2*104
tQGP [fm/c] <1 1.5-4 1-10
t0 [fm/c] 1? 0.5 <0.2?
tQGP/t0 1 6 30
ICHEP, 27-7-2002 P. Kuijer 3
Observables for Alice• AA Event by event!
– Particle multiplicities: scaling laws pp to AA
– Particle correlations: Flow (eq of state) and HBT (size, lifetime)
– Particle spectra: Kinetic freeze-out temperature + suppression
– Particle yields: Chemical freeze-out temperature + suppression
– Jets: Energy loss of partons in matter
– Direct photons: Yield increases strongly with T
– Heavy quark + quarkonia: pQCD production + modification in medium
• pp and pA– Global pp properties: baseline for AA
– Structure functions in nuclei (shadowing)
• Cosmics– muons around ‘knee’ region
ICHEP, 27-7-2002 P. Kuijer 4
Alice detectors
•Low pT cut-off
•Particle ID
•High granularity tracking
ICHEP, 27-7-2002 P. Kuijer 5
TRD e / PHOS /
TPC + ITS (dE/dx)
/K
/K
/K
K/p
K/p
K/p
e /
e /
HMPID (RICH)
TOF
ALICE uses ~all known methods
P [GeV/c] 0 1 2 3 4 5
P [GeV/c] 1 10 100
•p, K, identified in 2*1.8 units of by tracker (dE/dx) and TOF for 100 MeV/c up to several GeV/c
•e identified from 100 MeV/c to 100 GeV/c by tracker+TOF+TRD
•HMPID extends identification in small acceptance up to 5 GeV/c
•Photons with high resolution in PHOS, counting in PMD
ICHEP, 27-7-2002 P. Kuijer 6
HMPID
TOF
ITS+TPC
TPC
PID performance
ICHEP, 27-7-2002 P. Kuijer 7
SSD
0
50
100
150
200
250
300
350
1999 2000 2001
DAQ
Mass Storage (sust)
Mass Storage (peak)PHOS
• R&D phase finishing
PIX
SDD
0 100 200 300 400 500 600 700-50
0
50
100
150
200filter inputthreshold
0 100 200 300 400 500 600 700-50
0
50
100
150
200Filtered data and fixed threshold
filter outputthreshold
TPC
TOF
ICHEP, 27-7-2002 P. Kuijer 8
•Production phase starting
SSD support
HMPID module
Muon stations 3-4 and 1-2
TPC field cage
TPC RO chamber
Muon magnet yoke
PHOS crystals
ICHEP, 27-7-2002 P. Kuijer 9
• Point 2 ready to receive ALICE
TPC assembly hall taking shape
ICHEP, 27-7-2002 P. Kuijer 10
Alice collaboration
0
200
400
600
800
1000
1200
1990 1992 1994 1996 1998 2000 2002 2004
ALICE Collaboration statistics
LoI
MoU
TP
TRD
UKPORTUGAL
JINR
GERMANY
SWEDEN
CZECH REP.HUNGARYNORWAY
SLOVAKIAPOLANDNETHERLANDS
GREECE
DENMARKFINLAND
SWITZERLAND
RUSSIA CERN
FRANCE
MEXICOCROATIA ROMANIA
CHINA
USAARMENIA
UKRAINE
INDIA
ITALYS. KOREA
77 Institutions, 28 Countries
937 members (63% from CERN MS)
ICHEP, 27-7-2002 P. Kuijer 11
Summary
• Alice is an all-round Heavy Ion experiment– Excellent pT acceptance: 100 MeV/c up to 100 GeV/c
– Good particle ID
– The project is in transition from R&D to production
• The collaboration is still growing
• ALICE is on track for 2007!