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Performance of Aerogel Detectors. Yi Qiang for Pentaquark Experiment Collaboration Meeting March 14, 2005. Outline. Geometry and parameters of A1/A2 detectors Amplitude alignment PID performance. Geometry and Parameters. Aerogel index: A1 1.015 A21.055 Radiator area: - PowerPoint PPT Presentation
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Performance of Aerogel Detectors
Yi Qiangfor Pentaquark Experiment
Collaboration Meeting
March 14, 2005
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Outline
Geometry and parameters of A1/A2 detectors
Amplitude alignment
PID performance
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Geometry and Parameters
Aerogel index: A1 1.015 A2 1.055
Radiator area: A1 32X170 cm2
A2 30X192 cm2
Radiator thickness: A1 9 cm A2 5 cm
PMT types: A1 RCA8854 24 PMT
s A2 XP4572B 26 PMT
s
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Detector Configuration
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Amplitude Alignment
Typical single photon spectrum
The Alignment makes: A1 single photon peak = 100 A2 single photon peak = 60
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Sliced A1 sum spectrum after alignment
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Particle ID For index n, the threshold for Cerenkov
Radiation is β > 1/n
n(A1) = 0.015 n(A2) = 0.055
1/ n 1/ n dddd
dlkjdslfkjasdf
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Fit for A1/A2 sum spectra
Function: Poisson distribution convoluted with Gaussian
Fitted Parameters: Average N.P.E: μ Single Photon amplitude deviation: σ
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Puzzle in A1 sum spectra
Unexpected shape in A1 sum
Reason is still under investigation
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Electron A1 sum spectra Comparison of electron and pion A1 su
m spectra at 2.06 GeV/c
From electron spectrum, we have
Max N.P.E(A1) = 3.8
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Momentum Dependence of N.P.E for A1/A2 The average N.P.E is proportional to:
N ~ (1 – 1/β 2n2) Max N.P.E at β = 1
Max N.P.E(A1) = 3.8 Max N.P.E(A2) = 14.5
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
A1 efficiency
Fraction of kaon not firing A1
Using 550 MeV/c pion to simulate kaon condition
Fraction of pion not firing A1
e-μ = e- 3.8 = 2.2 %
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
A2 efficiency
Fraction of kaon not firing A2
e-μ = e- 9 << 1 Contamination from pion and c
ut selection
Pentaquark Experiment Collabration Meeting, JLab
Y.Qiang 2005-03-14
Overall PID performance
Selection of kaonEfficiency: 82%Pion Rejection: 90
Selection of pionEfficiency: 98%Kaon Rejection: 10
Compare to Original Performance (From Lingyan’s homepage)
N.P.E(A1): 8 → 3.8N.P.E(A2): 30 → 14.5
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