Oleksandr Grebenyuk

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Status of the EMC analysis
Physics capabilities of the electromagnetic
calorimeter Detector design Barrel EMC Endcap
EMC Calibration status MIP Pedestals
correction Towers status Summary
Oleksandr Grebenyuk
Utrecht, 9 September 2003
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Physics issues

• EMC (Barrel and Endcap) designed for the STAR
  spin physics program
• Physics topics for unpolarized pp, pA and AA
  (among others)
• p and ? spectra at large Pt
• Direct photons
• ?-jet correlations
• Single electrons (charm and bottom semileptonic
  decays)
• Di-electrons (J/? and ? decays)
• Global event characteristics (Et spectra)
• Gluon shadowing in pA (open charm, Drell Yan,
  dijets etc)
• EMC is also important for high-Pt level 0 trigger

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The STAR Detector
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EMC front/side view
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Module top/side view
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Module front view
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BEMC Module
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Megatile design
Tile readout
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Shower Maximum Detector
Wire proportional counter - strip read out
detector using gas amplification
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Shower Maximum Detector
Wire proportional counter - strip read out
detector using gas amplification
High spatial resolution for p reconstruction,
direct ? and e identification
1 module 300 strips
Total 120 modules, 36000 readout channels
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Preshower Detector
Integrated into each of the 4800 towers
First 2 scintillating layers 6 mm thick, 2
optical fibers are inserted
BEMC readout channels
Tower 4800
PSD 4800
SMD 36000
Total 45600
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Endcap EMC
Total EEMC
720 towers
0 f 360º
1 ? 2
Readout channels
Tower 720
Preshower 720
SMD 8640
Postshower 720
Total 10800
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Endcap EMC
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Barrel EMC installation
pp run
dAu run
AuAu run
8 full EMC
13 full EMC
50 full EMC
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EMC Calibration
Relative calibration (equalization) towers and
SMD strips, to achieve equal response to the hits
of equal energy
Pedestal correction pedestal runs data, saved
every 12 hours
Minimum Ionizing Particles (MIP)
Absolute calibration
pº measurements
Single electron spectra, using TPC momentum and
dE/dx
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EMC Calibration
Minimum Ionizing Particles (MIP)
High-p hadrons depositing 300 MeV due to
ionization
Cuts Track points to the EMC surface p gt 1
GeV/c 3x3 towers isolation
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EMC Calibration
Pedestals correction
Pedestals are taken every 12 hours and stored
in the STAR Database
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EMC Calibration
Detector status
Time-dependent towers and SMD status tables are
still missing
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Summary and outlook

• EMC gives access to a wide variety of physics
  topics in pp, pA and AA
• Present activity
• Get detailed understanding of the detector
• Provide time-dependent calibrations of the BEMC
• Calibration of SMD (topic not yet very well
  covered in STAR)