Capacitive%20coupling%20measurements.

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Capacitive coupling measurements.

• G. Vidal-Sitjes, J. Burguet-Castells,
• J.J. Gomez-Cadenas, A.M. Tornero Lopez.

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Reminder of the model
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Example bidirectional cross-talk
TPC pads, probe, DAQ
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Signal reconstruction phase-lock technique
One sector analyzed 645 alive channels (out of
662)
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Observation

• Huge spread of channels electronic gain
• 2.5 daughter channels per channel
• 79 of parent charge appears in other pads
• 1237 cross-talk relations (all orders)

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Order of the cross-talk signals.
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overall first order relations gt 62 of
cross-talk charge
65 of the parent signal charge
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First order relations
Map of first order relations map of couplings
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Relations relative position
R PHI
ROW
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Number and position of the parents
position of clean channels
325 clean channels
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Fitting the capacities subtracting the XT
signals
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Assessment of the cross-talk effect on the TPC
data with a fast MC simulation.

• G. Vidal-Sitjes, J.J. Gomez-Cadenas.
• With many thanks to Lara Scotchmer and Alexander
  Grossheim

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rF resolution. ANALOG signals.
non equalized
cross-talk
both
s1.8 mm
s0.6 mm
s1.6 mm
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rF resolution. DIGITIZED data (no threshold)
non equalized
cross-talk
both
s1.8 mm
s0.6 mm
s1.5 mm
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Energy resolution. Analog signals.
non equalized
cross-talk
both
s44
s13
s7
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Energy resolution. Digitized data. (no threshold)
non equalized 17
digitization 9
all 40
cross-talk 14
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Summary
rF
analog digital
non-eq. 0.6 mm 0.6 mm
x-talk 1.6 mm 1.5 mm
non-eq.x-talk 1.8 1.8
Energy
analog digital
digitization 9
non-eq. 13 17
x-talk. 7 14
non-eq.x-talk 44 40
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Conclusions

• Capacitive model applied to a full sector.
• Model describes well all data, including
  bidirectional and all orders cross-talk.
• Model fully specified by transfer functions
  (MEASURED) and by capacitances (COMPUTED)
• 92 of cross-talk reduced on this data
• ½ of the channels are clear. Assessment of
  performances without cross-talk ongoing.
• MC result shows that the effect is 1.5 mm in
  resolution and 15 in energy resolution.

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Outlook

• Apply correction algorithm on data and MC and
  compare residuals and energy resolution before
  and after correction.
• Prepare benchmark set of data to compare the
  performances of existing algorithms (resolution,
  minimum bias, speed).
• Choose the best combination of algorithms
  (require/expect close cooperation among different
  groups)