Performance of Aerogel Detectors Yi Qiang for Pentaquark Experiment Collaboration Meeting March 14, 2005
Dec 31, 2015
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
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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
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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