Heavy-Ion Meeting Yong Pyong, Korea, February 25-27, 2010 Particle Detectors for Relativistic i Heavy-Ion Collisions Byungsik Hong Korea University it February 25-27, 2010 Heavy-Ion Meeting 1
Introduction Outline - I will skip the physics motivation! - What are the basic ingredients of relativistic heavy-ion collision experiments? - How have they been developed? Principles of Particle Detection - What needs to be measured? - How to measure them? Some Examples - Mostly, RHIC & LHC experiments February 25-27, 2010 Heavy-Ion Meeting 2
Basic Ingredients Relativistic Heavy Ion Collision Experiment Heavy Ions or, essentially, heavy nuclei High-energy accelerators Detectors and most importantly people February 25-27, 2010 Heavy-Ion Meeting 3
Accelerators Many generations of accelerators provided higher and higher energy beam particles for experiments 1929 ¾ of century later CMS LHCb ALICE ATLAS LHC at CERN (1901-1958) (27 km circumference) Ernest Lawrence February 25-27, 2010 Heavy-Ion Meeting 4
HI Accelerators in the meantime BEVALAC(=Bevatron+SuperHILAC) at LBNL Billions of ev Synchrotron (1971-1993) 1 1993) Discovery of antiproton in 1955 by E. Segrè & O. Chamberlain (Nobel Prize in Physics 1959) February 25-27, 2010 Heavy-Ion Meeting 5
HI Accelerators in the meantime AGS (Alternating Gradient Synchrotron) at BNL (1986-1996) Discovery of ν μ in 1962 by L. Lederman, M. Schwartz & J. Steinberger (Nobel Prize in Physics 1988) Discovery of CP violation in 1963 by J. W. Cronin & V. L. Fitch (Nobel Prize in Physics 1980) Discovery of J(/ψ) particle and charm quark in 1974 by S. Ting (Nobel Prize in Physics 1976) February 25-27, 2010 Heavy-Ion Meeting 6
HI Accelerators in the meantime SPS (Super Proton Synchrotron) at CERN (1986-Present) Discovery of W & Z in 1983 by UA1 & UA2 experiments (C. Rubbia & S. Van de Meer: Nobel Prize in Physics in 1984) February 25-27, 2010 Heavy-Ion Meeting 7
HI Accelerators in the meantime SIS18 (Heavy Ion Synchrotron in German) at GSI (1990-Present) GSI at present KaoS February 25-27, 2010 Heavy-Ion Meeting 8
HI Accelerators in the meantime RHIC (Relativistic Heavy Ion Collider) at BNL (2000-Present) STAR February 25-27, 2010 Heavy-Ion Meeting 9
Comparison of Beam Energy Accelerator s NN (GeV) Status SIS18 2A (GSI, Germany) (A = mass number) Running AGS (BNL, USA) 5A Finished SIS300 Plan to run from 8A (GSI, Germany) ~2016 SPS S (CERN, Switzerland) 18A Finish i soon RHIC (BNL, USA) 200A Running from 2000 LHC (CERN, Switzerland) 5500A Plan to start in 2010 February 25-27, 2010 Heavy-Ion Meeting 10
Development of Energy Total center-of-mass energy versus time 1.E+07 1.E+06 LHC LHC Pb sq qrt(s) - 2m 1E 1.E+05 1.E+04 1.E+03 1.E+02 1.E+01 RHIC SPS AGS x 28 x 13 x5.5 55 PS/AGS ISR FNAL SppS TeV Bevalac RHIC LHC SPS S/Pb AGS Si/Au 1.E+00 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Year February 25-27, 2010 Heavy-Ion Meeting 11
Old-Fashioned Detector Tool to measure something Issac Newton (1642-1727) Ernest Rutherford (1871-1937) Eyes Fluorescent (ZnS) Screen February 25-27, 2010 Heavy-Ion Meeting 12
Old-Fashioned Detector Bubble Chamber BEBC: Big European Bubble Chamber February 25-27, 2010 Heavy-Ion Meeting 13
Modern Detector There is a clear limitation in accumulating statistics with old-fashioned detectors. In these days, we want to measure one particle in several hundred millions or billion collision events. We usually use electronics devices to record huge amount of data for a given time. For example, several hundred MB data per second for each LHC experiment First multi-channel electronics detector Multi-wire proportional chamber (MWPC) Invented by G. Charpak in 1968 Nobel Prize in Physics in 1992 February 25-27, 2010 Heavy-Ion Meeting 14
Ionization Detector Principle Number of free electrons at x : n = n0 exp( α x) Multiplication factor : M = n n Condition for ionization process : α x < 0 ( α : Townsend coefficient) = exp( α x ) 20 (Raether limit) February 25-27, 2010 Heavy-Ion Meeting 15
Multi-Wire Proportional Chamber Electric Field Lines in MWPC We can get more accurate position information by using the arrival time and drift velocity of electrons Drift Chamber February 25-27, 2010 Heavy-Ion Meeting 16
Time Projection Chamber ALICE TPC Total volume = 88 m 3 Length = 5 m Diameter = 5.6 m # of channels = 570k Drift gas (Ne:CO 2 :N 2 =86:9:5) February HV 25-27, membrane 2010 (25 μm) Heavy-Ion Meeting Field Cage 17
Time Projection Chamber V/cm) de/dx (kev STAR Momentum (GeV/c) Lines: Bethe-Bloch Equation February 25-27, 2010 Heavy-Ion Meeting 18
Scintillation Detector & PMT Scintillation plastic or crystal Photomultiplier Tube (PMT) February 25-27, 2010 Heavy-Ion Meeting 19
Scintillation Material February 25-27, 2010 Heavy-Ion Meeting 20
Semiconductor Detector Band Structure For doped semiconductor n-type (As, P, Sb, etc.) p-type (Ga, B, In, etc.) February 25-27, 2010 Heavy-Ion Meeting 21
Semiconductor Detector pn-junction Inversed bias increases the depleted volume Depletion region = Effective volume for the particle detection Maximum inversed voltage, V max, determined by ρ of semiconductor February 25-27, 2010 Heavy-Ion Meeting 22
CMS Silicon Tracker Largest Si detector ever built (66M Si Pixels+11M Si Strips) February 25-27, 2010 Heavy-Ion Meeting 23
CMS Silicon Tracker February 25-27, 2010 Heavy-Ion Meeting 24
CMS Silicon Tracker Ready for installation February 25-27, 2010 Heavy-Ion Meeting 25
Calorimeter Apparatus to measure the energy of particles Classification by Function - Electromagnetic(EM) Calorimeter - Hadronic(HD) Calorimeter Classification by Structure - Homogeneous Calorimeter - Sampling Calorimeter PHENIX FOCAL (Forward Calorimeter) EM Calorimeters HD Calorimeters π 0 /γ identifier (strip-pixels) Si sensors pads tungsten February 25-27, 2010 Heavy-Ion Meeting 26
Principles of Particle Detection Click the above figure February 25-27, 2010 Heavy-Ion Meeting 27
FOPI Detector @ SIS18 Forward Drift Chamber Multigap RPC ToF Backward Plastic ToF Forward Plastic ToF Beam Mid-rapidity idit Drift Chamber Superconducting Magnet February 25-27, 2010 Heavy-Ion Meeting 28
PHENIX Detector @ RHIC February 25-27, 2010 Heavy-Ion Meeting 29
PHENIX Upgrade FVTX Si Endcaps FOCAL Forward Calorimeter VTX Si Barrel RPC3 RPC1 RPC3 February 25-27, 2010 Heavy-Ion Meeting 30
STAR Detector @ RHIC February 25-27, 2010 Heavy-Ion Meeting 31
ALICE @ LHC Size: 16ⅹ16ⅹ26 m 3 Weight: 10,000 tons 23-27 February, 2010 APCTP 2010 YongPyong 32
ATLAS Detector @ LHC An Excellent Calorimetry A large acceptance Inner Tracker A hermetic Muon Spectrometer 23-27 February, 2010 APCTP 2010 YongPyong 33
CMS Detector @ LHC Superconducting Coil (4 T) CALORIMETERS ECAL 76k scintillating PbWO 4 crystals HCAL Plastic scintillator/ Brass Sandwich Steel YOKE TRACKER Pixels (66M Ch.) Silicon Microstrips (9.6M Ch.) 220 m 2 of silicon sensors Level-1 Trigger Output Up to 100 khz Directly feeds HLT CPU farm Weight: 12,500 tons Diameter: 15 m Length: 22 m MUON BARREL Drift Tube Chambers Resistive Plate Chambers MUON ENDCAPS Cathode Strip Chambers Resistive Plate Chambers
ATLAS vs. CMS ATLAS is twice as big, but CMS is twice as heavy six-story building ATLAS (2 Tesla) CMS (4 Tesla) 23-27 February, 2010 APCTP 2010 YongPyong 35
ATLAS vs. CMS Different technologies but close acceptances possibility to cross-check ATLAS Inner Det. ( η <2.5) ECAL ( η <3.2) HCAL ( η <3.2) HF (3.2< η <5) Muon ( η <2.7) Lucid (5.5< η <6) ZDC ( η >8) Castor HF Inner detector ECAL, PbWO4 0.0174x0.0174 HCAL (sampling) 0.087x0.087087 0 087 (HB) 0.087->0.17 (HE) HF Castor CMS Inner Det. ( η <2.5) ECAL ( η <3) HCAL ( η <3) HF (3< η <5) Muon ( η <2.4) Castor (5< η <6.7) ZDC ( η >8) 23-27 February, 2010 APCTP 2010 YongPyong 36 Muon Spectrometer
KRIB Multipurpose Spectrometer @ KoRIA February 25-27, 2010 Heavy-Ion Meeting 37
Summary Incredible technological advances for the last ~100 years or so - Accelerators - Detectors Al lot of applications i of the particle detectors Many dedicated di d experts are (and will be) needed. Future is extremely bright! February 25-27, 2010 Heavy-Ion Meeting 38