Cosmic run analysis for IFR-LST

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Cosmic run analysis for IFR-LST
G. Cibinetto
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Outline

• Type of cosmic runs
• Mapping and mis-mapping
• Occupancy plots
• noisy channels
• dead channels
• Detector optimization
• single rate
• threshold scan
• efficiency plots
• Reconstruction

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Type of cosmic runs

• Beside the conventional BaBar cosmic triggers we
  use a standalone data taking mode triggering on
  each singular hit in the wires of the LSTs
• This way we trigger also on the noise.
• The standalone mode has been used to measure the
  performances and to optimize the detector (single
  rate, threshold scan, search for dead/hot
  channels)

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Hitmaps at the FEC level
view 0 (? wires)
view 1 (z strips)
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Mapping and
masked channels
missing channel
wire n. vs FEC channel layer 5 sxt 1
strip n. vs FEC channel layer 8 sxt 1
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mis-mapping
When one strip is hit in a layer, plot location
of hit strips in adjacent layers
wrongly mapped layer
correctly mapped layer
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Occupancy plots
Noisy FECs
Dead channel
Hot spot in the tube
This noisy channel is due to an hot spot in one
of the tube. The channel is recovering (blue
plot) being under HV.
The 2 hot channels were due to noisy FECs which
have been replaced. The hole is a dead z channel
(the strips got disconnected).
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1D Cluster Reconstruction
Average multiplicity 1.13
Average multiplicity 1.82
strip multiplicity
wire multiplicity
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Detector optimization single rate measurement
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Detector optimization threshold scan
For wire signals
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Detector optimization efficiency measurement
Average layer efficiency is 92.5
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Detector optimization efficiency vs threshold
No efficiency variations as function of the
threshold
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1D Cluster Map (LST Geometry)
Matteo Negrini
Reconstructed 1D cluster positions using new
geometry packages in release 15.7.0
wires
strips
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Summary

• Cosmic runs have been and are very useful for the
  detector optimization and performances
  monitoring.
• The installed detectors perform excellently,
  according to expectations.
• 288 tubes installed ? 1152 R/O channels, all
  working properly !!!
• 1612 z-strips installed and tested, only 5 bad
  channels !!!
• Average layer efficiency is 92.5.
• Noise from electronics is negligible.
• 1D cluster reconstruction using new geometry is
  ready.
• 3D reconstruction used to checked the alignment
  of the layers and to improve the geometry (not
  presented here).
• Next step colliding events.