Electron Measurement in the ALICE

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Electron Measurementin the ALICE
DongHoonLee, J.H.Kang, B.S.Chang, Y.I.Kwon,
M.G.Song, M.W.Kim
for ALICE collaboration
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FROM http//aliceinfo.cern.ch
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TRD(Transition Radiation Detector)
?lt0.9, 45lt?lt135 18 supermodules in F
sector 6 Radial layers 5 z-longitudinal
stack ? total 540 chambers ? 750m² active
area ? 28m³ of gas In total 1.18 million
read-out channels
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• TRD ????

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Charged particle Identification by
ALICEaccording to particle momentum.
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What is the transition radiation?
Transition radiation is emitted whenever a
charged particle crosses an
interface between two media with
different dielectric functions.
- L.Durand, Phys.
Rev. D 11, 89(1975)
Predicted Ginzburg Frank, 1946 Observed
Goldsmith Jelly, 1959(optical) Its
sizeable(X-rays) for relativistic particles.
Bremsstrahlung
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TRD working principle
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From ALICE Physics Performance Report
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(No Transcript)
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1 Event signals of Electron and Pion
purse height
electron
t
0
3µs
purse height
Pion
t
0
3µs
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e/p-Separation(Likelihood method)
Pion efficiency as a function of number of layers
for a momentum of 2GeV/c
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Neural Network

• Neural-Network
• A simple modeling of the biological neuron system
• Being used in various fields for data analysis
  and classification
• Examples
• Image analysis
• Financial movements prediction
• Sales forecast
• In particle physics

Weight of connection
x1
Output
UNIT
y
Inputs
xn
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Performance of Neural Network
90 electron efficiency, 6 layers
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Summary

• ALICE can detect electron in a wide momentum
  range.
• TRD plays a key role.
• TRD covers a large acceptance, full f with
  ?lt0.9
• TRD gets additional pulse from Transition
  Radiation useful in pattern recognition.
• Neural Net based approach can improve electron
  identification.