SSD beamtest analysis Stphane Plumeri Institut de Recherches Subatomiques IReS, Strasbourg

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SSD beamtest analysis Stéphane Plumeri
Institut de Recherches Subatomiques (IReS),
Strasbourg
ALICE collaboration

• ITS week 20 23 October 2003

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Outlook

• StripTracking software
• Noise, pedestal and common mode shift
• Signal and signal to noise ratio
• Cluster shape
• Charge matching
• Conclusion

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StripTracking software

• Authored by Dirk Meier at CERN (1997)
• and modified by J. Baudot, C. Suire and S.Plumeri
  (IReS)
• for STAR and ALICE SSD beamtests.
• StripTracking is a C program linked with root
  libraries
• StripTracking can
• Measure noise and pedestal
• Find hits
• Correlate hits on each side

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Noise
ITCs modules Module 3 357 e- P side 573 e-
N side Module 4 365 e- P side 573 e- N side
Canberras modules Module 1 440 e- P side
1458 e- N side Module 2 415 e- P side 1369 e-
N side
For each module V 45V
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Pedestal
Pedestal mean value of charge over the run
2100 2200 ADC counts for all modules Nearly the
same for N and P side
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Common mode shift
Standard deviation of cms distribution over
events, with
Seems to increase with distance from power supply
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Signal
Charge in clusters (threshold seed strip S/Ngt5
neighboors S/Ngt3 )
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Signal
Charge in clusters (Correlation between two sides
and geometrical cut)
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Signal to noise ratio
Problem on canberras module N side
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Cluster shape
Bad results on canberras N side
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Charge matching
Default on ITCs module maybe due to noisy
strips ?
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Conclusion

• Good modules performances
• But
• Origin of high cms?
• Too much noise on N side of canberras module
• Next step Tracking