Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 1

ÚEF SAV a ALICE

A LARGE ION COLLIDER EXPERIMENT FOR THE LHC - CERN LARGE HADRON COLLIDER

Ladislav Šándor Oddelenie subjadrovej fyzikyÚstav experimentálnej fyziky SAV

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 2

Why heavy ions at high energies ?• QCD prediction on a new state of matter (QGP) formation at high

enough energy density• Experiments at the CERN SPS (√sNN = 17 GeV) – observation of

new collective effects (anomalous J/suppression, strangeness enhancements, dilepton spectra anomalies)

• Experiments at the RHIC in BNL - (√sNN = 200 GeV) confirm SPS results and reveal the presence of other QGP signatures too

Next natural step to higherenergy (√sNN = 5.5 TeV) – building of the dedicated ion experiment for the new CERN accelerating complex LHC

project ALICE

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 3

Why Slovakia in ALICE ?

• Active work of Slovak physicists (both experimentalists and theorists) in heavy-ion physics for about two decades

• Fruitful experience from a number of SPS experiments (NA34-Helios, WA97, NA49, NA57)

• Unique potential of ALICE – the only dedicated heavy-ion experiment at LHC – for A-A, p-A and also p-p physics attracting interest of

qualified teams from Bratislava and Košice to continue working in heavy-ion physics

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 4

Large Hadron Collider

aéroport

Genève 3.8 m diameter circular tunnel circumference of ring – 27 kmburied 50 to 175 m underground

Aerial view with location of experimentshttp://lhc.web.cern.ch/lhc/

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 5

LHC experiments

Slovak participation

Energy of protons – up to 7 TeV per beam. Available energy in p-p reaction is

√s = 14 TeV( 7 x higher wrt Tevatron).

For lead ion (Pb-Pb) collisionsenergy for pair of nucleons is

√sNN = 5.5 TeV

( ~30 x higher wrt RHIC)

Start of LHC operation : late 2009 (data collection for physics at 5 TeV per proton beam starting end of October)

Colliding of two counter rotating proton or heavy-ion beams

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 6

ALICE design philosophy• General Purpose Heavy Ion Detector only one dedicated heavy-ion experiment at LHC (ATLAS/CMS will contribute, but their priority is pp physics) AGS/SPS : several (6-8) special purpose experiments RHIC : 2 large multipurpose, 2 smaller special purpose expts • cover essentially all known observables comprehensive study of hadrons at midrapidity (large acceptance, excellent tracking and particle identification (PID) state-of-art measurement of direct photons (excellent resolution & granularity EM calorimeter) dedicated & complementary systems for di-electrons and di-muons cover the full spectrum from soft (10’s MeV) to hard (100’s GeV)• stay open for changes & surprises

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 7

ALICE experimentMain physics goals: ultrarelativistic nucleus- nucleus collisions in extreme conditions (high pressure and energy density) physics of the QCD vacuum detailed investigation of new state of matter – the Quark-Gluon Plasma general characteristics of p-p interactions in a new energy domain

Difficult experimenting withhigh demands on computing

Total cost: ~150 MCHFSlovak contribution: 0.8 MCHF

Details on ALICE : http://aliceinfo.cern.ch/

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 8

What are we going to cope with

Expected multiplicity in central Pb-Pb: dNch/d ~ 1500 – 6000

in Pb-Pb collisions at LHC ?

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 9

SOUTH AFRICA

UKPORTUGAL

JINR

GERMANY

SWEDEN

CZECH REP.HUNGARYNORWAY

SLOVAKIA

POLANDNETHERLANDS

GREECEDENMARK

FINLAND

SWITZERLAND

RUSSIA CERN

FRANCE

MEXICOCROATIA

ROMANIA

CHINA

USAARMENIA

UKRAINE

INDIA

ITALY

S. KOREA

> 1000 members 90 institutions 30 countries

~ 25 Slovak physicists and engineers

ALICE collaboration

Participating institutes:- Comenius University Bratislava, team leader : B. Sitár contribution to the TPC detector (read-out chambers) and to the DCS – the detector control system- Institute of Exp. Physics SAS, P.J. Šafárik University Košice, team leader : L. Šándor router electronics for the SPD (Silicon Pixel Detector) and contribution to the CTP - the central trigger system, radiation studies

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 10

Inner Tracking System (ITS)

Rout=43.6 cm

Lout=97.6 cm

SPD

SSD

SDD

6 layers, three technologies, material budget < 1% Xo per layerSPD – silicon pixel detector (0.2 m2, 9.8 Mchannels)(0.2 m2, 9.8 Mchannels)SDD – silicon drift detector (1.3 m2, 133 kchannels)SDD – silicon drift detector (1.3 m2, 133 kchannels)SSD – silicon strip detector (4.9 m2, 2.6 Mchannels)SSD – silicon strip detector (4.9 m2, 2.6 Mchannels)

Silicon Pixel Detector

• Two SPD layers at r = 3.9 & 7.6 cm• Structured to 60 staves containing 9.8 M active pixel channels

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 11

SPD readout architectureDCS

Trigger

DAQ

JTAG, CLK, Detector Data

~100m

PCI-MXI-II-VME

VME Router C(ard

one router services 6 halfstavesSPD contains 20 router boards

Košice commitment(J. Bán, M. Krivda)Cost : 6 MSK (240 kCHF)

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 12

Some important dates ...• approval of LHC ............................. 16.12.1994

• approval of ALICE experiment .......... 6.02.1997

• preliminary agreement on the router electronics development in Kosice .... spring 1999 • workshop on ALICE SPD electronics in Kosice, about 20 participants from CERN, Birmingham, Budapest, Italian laboratories, presentation of the SPD router project (J. Bán) ... 22-24 Nov 1999

• green light for the router electronics 24.11.1999

• router production finished .............. august 2006

• installation and integration of routers in ALICE experimental area … summer-autumn 2007

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Inštalácia SPD

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ITS s vákuovou trubicou

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T D Lee, May 2004

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T D Lee, May 2004

Úvod – celoústavný seminár ÚEF , 11.02.2009 L. Šándor 18SQM 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） 1818