Download presentation_clic_pequegnot_4sept_v1

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Desy TestBeam
Anne-Laure Pequegnot
Mathieu Benoit
sommaire
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Desy test beam analysis progress:
Alignment of the Timepix detector
Wednesday 4th September
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Outline
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Introduction
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Technical details
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Progress
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Conclusion
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INTRODUCTION
TELESCOPE
All the plots in the following are for the run 48:
 energy: 4.4 GeV
 TOT mode
 frequency: 96 MHz
 voltage: 15 Volts
 sensor: 50 μm thickness, 20 μm edge
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TECHNICAL DETAILS
SUMMARIZE FROM LAST TIMES
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oWe aligned tracks to DUT with the 3-step-alignment method:
 find the rotation (min RMS) and fix it ;
 find the X-translation (mean → 0) and fix it ;
 find the Y-translation (mean → 0) and fix it.
o We use the tracks to predict the particle position on the DUT
o Charged particles fire pixels when they go through the DUT and we used 4 different
methods to reconstruct the hits :
 Q-weighted centroid: pixels center mean weighted by their energy
 Digital centroid: geometrical center of the firing pixels
 MaxTOT: center of the pixel with the highest energy
 EtaCorrection: based on the Q-weighted, using a non-linear charge sharing distribution
o In the following, residuals: difference between charged particle positions in the DUT
predicted by the EUDET telescope and the one measured from the hit pixels.
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TECHNICAL DETAILS
SUMMURIZE: ETA CORRECTION
reality
100 %
Q-weighted centroid:
linear charge sharing
between pixels
50 %
Pixel 1
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The η function describes the charge sharing distribution.
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80.5
Pixel 2
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PROGRESS
ETA CORRECTIONS AND CLUSTER TOPOLOGIES
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 We have several cluster topologies:
Size 1 (1x1)
Size 2 (1x2)
Size 2 (2x1)
Size 2 (2x2)
Size 3 (2x2)
Size 4 (2x2)
Asymetry: small angle
around X axis?
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Ex: size 3 (3x3)
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PROGRESS
HIT PROBABILITY: TRACKS
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PROGRESS
ENERGY SPECTRUM
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Energy calibration
effect (TOT)
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PROGRESS
ETA CORRECTIONS AND CLUSTER TOPOLOGIES
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Recall:
X residuals = Xtrack – Xtimepix
Y residuals = Ytrack – Ytimepix
Size 2 (1x2)
Size 2 (2x1)
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Size 2 (2x2)
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PROGRESS
ETA CORRECTIONS AND CLUSTER TOPOLOGIES
Recall:
X residuals = Xtrack – Xtimepix
Y residuals = Ytrack – Ytimepix
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Size 4 (2x2)
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PROGRESS
ETA CORRECTIONS
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QWeighted
EtaCorrection
σ dut= 10.6 μm
No more X-Y
asymetry
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Improvement of the Timepix
resolution
σ tel= 3 μm
σ dut= 2.7 μm
No more X-Y
asymetry
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CONCLUSION
PLANS FOR THE FUTUR
 Understand the results for the other cluster sizes
 Study the other runs
 Write my summer student report
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sommaire
Backup
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BACKUP
SIGMA OPTIMIZATION
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 We wrote an algorithm who gives us the σ value of the charge sharing corresponding to
the best hits energy resolution (σ of the residuals)
 Plots for the cluster size 2 (2x1 and 1x2)
Recall:
X residuals = Xtrack – Xtimepix
Y residuals = Ytrack – Ytimepix
 We can clearly see an assymetry between X and Y residuals: sensor angle? beam angle?
 Using the mean of σx and σy for the moment.
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RESULTS FROM RUN 131
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 We have several cluster topologies:
Size 1 (1x1)
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Size 2 (1x2)
Size 2 (2x1)
Size 2 (2x2)
Size 3 (2x2)
Size 4 (2x2)
Ex: size 3 (3x3)
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BACKUP
RESULTS FROM RUN 131
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 We implemented the eta corrections for the following cluster topologies:
Size 2 (1x2)
Size 2 (2x1)
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Size 2 (2x2)
Not yet understood: work in progress
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BACKUP
RESULTS FROM RUN 131
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 General results:
σ = 15.5 μm
σ = 14.7 μm
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σ = 12.3 μm
σ = 11.3 μm