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STAR Detector

STAR Detector. Introduction STAR Detector Time Projection Chamber EMC, FPD, RICH Trigger Detectors ZDC, CTB, BBC Generic Characteristics of RHIC Event. 2 concentric rings of 1740 superconducting magnets 3.8 km circumference counter-rotating beams of ions from p to Au.

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STAR Detector

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  1. STAR Detector • Introduction • STAR Detector • Time Projection Chamber • EMC, FPD, RICH • Trigger Detectors • ZDC, CTB, BBC • Generic Characteristics of RHIC Event Zhangbu Xu (BNL) USTC lecture

  2. 2 concentric rings of 1740 superconducting magnets 3.8 km circumference counter-rotating beams of ions from p to Au RHIC @ Brookhaven PHOBOS BRAHMS Relativistic Heavy Ion Collider PHENIX STAR h Long Island Zhangbu Xu (BNL) USTC lecture

  3. RHIC – Runs in 2000 and 2001 17 Aug – 2 Oct Performance (2001)Au + Au snn 200 GeV L [cm-2 s -1 ] > 2 x 1025 (>10% design) * 5 m  2 m # bunches 56  112 Performance (2000)Au + Au snn 130 GeV L [cm-2 s -1 ] ~ 2 x 1025 (10% design) * 5 m # bunches initially 6, later 56 Zhangbu Xu (BNL) USTC lecture

  4. Luminosity Calculation in Collider • Van Der Meer Scan • Absolute Normalization for AA, pp • Scaling pp, pA, AA STAR Preliminary 300m Blue/Yellow Beams Zhangbu Xu (BNL) USTC lecture

  5. The STAR Collaboration Poland:Warsaw University, Warsaw University of Technology Russia: MEPHI – Moscow, LPP/LHE JINR–Dubna, IHEP-Protvino U.S. Labs:Argonne, Berkeley, Brookhaven National Labs U.S. Universities:Arkansas, UC Berkeley, UC Davis, UCLA, Carnegie Mellon, Creighton, Indiana, Kent State, MSU, CCNY, Ohio State, Penn State, Purdue,Rice, Texas A&M, UT Austin, Washington, Wayne State, Yale Brazil: Universidade de Sao Paolo China:IHEP - Beijing, Institute of Modern Physics, Lanzhou IPP – Wuhan, Tsinghua, SINAP, USTC England:University of Birmingham France: SUBATECH – Nantes Institut de Recherches Subatomiques,Strasbourg Germany: Max Planck Institute – Munich University of Frankfurt India: Bhubaneswar, Kolkata, Mumbai , Panjab, Rajasthan Spokesperson: Nu Xu Countries: 13 Institutions: 47 Collaborators: 451 Students: ~50 Zhangbu Xu (BNL) USTC lecture

  6. Time Projection Chamber Magnet Coils Silicon Vertex Tracker TPC Endcap & MWPC FTPCs ZCal ZCal Endcap Calorimeter VertexPositionDetectors Barrel EM Calorimeter Central Trigger Barrel or TOF RICH A TPC is at the heart of STAR at RHIC Zhangbu Xu (BNL) USTC lecture

  7. Largest TPC in the World Zhangbu Xu (BNL) USTC lecture

  8. Gas: P10 ( Ar-CH4 90%-10% ) @ 1 atm Voltage : - 31 kV at the central membrane 148 V/cm over 210 cm drift path 420 CM TPC Gas Volume & Electrostatic Field Cage Self supporting Inner Field Cage:Al on Kapton using Nomex honeycomb; 0.5% rad length Zhangbu Xu (BNL) USTC lecture

  9. 60 cm 190 cm Outer and Inner Sectors of the Pad Plane • 24 sectors (12 on a side) • Large pads good dE/dx resolution in the Outer sector • Small pads for good two track resolution in the inner sector Outer sector 6.2 × 19.5 mm pads 3940 pads Inner sector 2.85 × 11.5 mm pads 1750 pads 70 Millions readout Channels Zhangbu Xu (BNL) USTC lecture

  10. Cartoon of Signal Collection in TPC Zhangbu Xu (BNL) USTC lecture

  11. Pixel Readout of a Pad Plane Sector A cosmic ray + deltaelectron Zhangbu Xu (BNL) USTC lecture

  12. STAR Event @ 200GeV Zhangbu Xu (BNL) USTC lecture

  13. All calculated distortions Before > 200 mm 180 Track Residuals (cm) Inner sector 140 Outer sector 100 Radius (cm) After < 50 mm 60 Distortion scale ± 1.5 mm 20 Track Residuals (cm) -200 -100 0 100 200 Inner sector Outer sector Z (cm) Many Small Effects – B, E, Clock, Twist, CM … Zhangbu Xu (BNL) USTC lecture Hui Long, Steve Trentelange(UCLA), JT (LBNL)

  14. 12 d p 8 K dE/dx (keV/cm)  4 m e 0 Anti - 3He Offline Particle Identification: dE/dx Aihong Tang (Kent State U) dE/dx PID range: ~ 0.7 GeV/c for K/ ~ 1.0 GeV/c for K/p Zhangbu Xu (BNL) USTC lecture

  15. f from K+ K- pairs dn/dm background subtracted m inv dn/dm K+ K- pairs same event dist. mixed event dist. m inv Particle ID via Topology & Combinatorics Secondary vertex: Ks p + p  L p + p X  L + p  W L + K g  e++e- Ks p + + p - f  K + + K- L  p + p - r  p + + p - “kinks” K  +  Zhangbu Xu (BNL) USTC lecture

  16. TPC Photon Conversion X-Raying Reaction&TPC Material 1-3% Efficiency Zhangbu Xu (BNL) USTC lecture

  17. Electromagnetic Calorimeter Leading Particle Zhangbu Xu (BNL) USTC lecture

  18. Proton Spin BEMC, EEMC, FPD Zhangbu Xu (BNL) USTC lecture

  19. Zero Degree Calorimeter Paddles/BBC ZDC ZDC Au Au Paddles/BBC Central Multiplicity Detectors Zhangbu Xu (BNL) USTC lecture

  20. … with nuclear excitation AuAu -> Au*Au*r0 5% Central STAR Calibration&Vertexing Zhangbu Xu (BNL) USTC lecture

  21. CTB&BBC Zhangbu Xu (BNL) USTC lecture

  22. Trigger Timing • Heart beat: RHIC Clock • Event Trigger: ZDC, CTB • L0 Decision: 1.5s • L1, L2: 2ms • TPC Readout: 2K • L3 Online Analysis: 1/100 s • DAQ Rate: • 1 Hz central event (2000) • 6Hz (2001) • >20Hz (2002) • Data Rate per week: 3.6M (30% Eff, 2002) Zhangbu Xu (BNL) USTC lecture

  23. Data Formats RAW DATA • Raw Data: • Bank Structure • Word: ADC, TIME • Final Data: • ROOT BASED • TTree • Track Parameters DST: TTree in ROOT Zhangbu Xu (BNL) USTC lecture

  24. Woods-Saxon distribution Overlap Integral #collisions A #interacting nucleons Geometry Zhangbu Xu (BNL) USTC lecture

  25. Mapping with Data Zhangbu Xu (BNL) USTC lecture

  26. Centrality and Participants HIJING1.35 Glauber Model Zhangbu Xu (BNL) USTC lecture

  27. Paddles/BBC ZDC ZDC Au Au Paddles/BBC Central Multiplicity Detectors 5% Central Paddle signal (a.u.) STAR Geometry from Experiments Zhangbu Xu (BNL) USTC lecture

  28. Differential Cross Section Exponential Boltzmann Gaussian Lorentz Invariant Yield per event Zhangbu Xu (BNL) USTC lecture

  29. Summary • Largest TPC works well • There are many exciting results • Additional Capability (MRPC TOF) • Come and Join STAR • Hardware • Analysis Zhangbu Xu (BNL) USTC lecture

  30. Preliminary sNN = 200 GeV 130 GeV nucl-ex/0206011 Preliminary sNN = 200 GeV Charged hadron pt spectra Zhangbu Xu (BNL) USTC lecture

  31. Multiplicity &<pT> Zhangbu Xu (BNL) USTC lecture

  32. p-, K-, p Spectra pp  uncorrected for trigger bias and vertex finding efficiency 200 GeVCentral Au+AuPreliminary • p+p: same slope • AA: different slope p- K- p Zhangbu Xu (BNL) USTC lecture

  33. Model Predictions I: ColorGlassCondensate • Qs2 ~ s(xGA(x, Qs2))/(RA2) • dNch/d/(RA2)  Qs2/ s • dNch/d/Npart  1/ s Gluon Saturation Relevant Scale:Qs2dNch/d/(RA2) Zhangbu Xu (BNL) USTC lecture

  34. hard soft Model Predictions II: “Soft”+”Hard” dNch/d = (1/2) Npartnssoft + nhNbinjet/in hard minijet contribution Npart: # wound incoming Nucleons Nbin: # Interactions of Incoming Nucleons p0 Zhangbu Xu (BNL) USTC lecture

  35. Gluon Saturation: Multiplicity D. Kharzeev, et al., nucl-th/0108006 Multiplicity Comparison: centrality and pseudorapidity dependence Model assumes: gluons from initial state directly hadrons Zhangbu Xu (BNL) USTC lecture

  36. Gluon Saturation: pT Spectra Nucl-th/0108048 pT spectra comparison: beam energy and centrality dependenceWorks well the <pT> should also reflect the gluon momentum Qs. Saturation model: J. Schaffner-Bielich, et al. nucl-th/0108048 D. Kharzeev, et al. hep-ph/0111315 Zhangbu Xu (BNL) USTC lecture

  37. Gluon SaturationThermalization? A.H. Mueller QM02 A different view on the consequences of gluon saturation Zhangbu Xu (BNL) USTC lecture

  38. Universal Particle Production? OPAL e+e- PLB94 Universalor not?? PHOBOS QM02 M. Szczekowski PRD 44 (1991) R577 Zhangbu Xu (BNL) USTC lecture

  39. C6F14 Quartz CH4 STAR Ring Imaging Cherenkov Detector • PID for Kaon/Pion/Proton • 1-3 GeV/c for K/ • 1.5-5 GeV/c for p/anti-p • C6F14 Liquid Radiator • CsI Photo Cathode • MWPC with 16,000 Pads Zhangbu Xu (BNL) USTC lecture

  40. GAS System Liquid PreTrigger HV RICH TRG RICH Detector SLOW Control DB Readout STAR TRIGGER RICH DAQ STAR DAQ DATA RCF ONLINE RICH ONLINE Trigger Scheme (RICH) Zhangbu Xu (BNL) USTC lecture

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