Transcript ppt

GLAST LAT Project
LAT Instrument Analysis Meeting– Jan 20, 2006
GLAST Large Area Telescope:
Gamma-ray Large
Area Space
Telescope
TKR 16-Tower Data
Hiro Tajima (SLAC)
Mustumi Sugizaki (SLAC)
TKR
[email protected]
650-926-3035
Hiro Tajima, TKR 16-tower data
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GLAST LAT Project
LAT Instrument Analysis Meeting– Jan 20, 2006
TKR analysis with 16-tower data
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Run range: 135005345 – 135005524. (B/2, B/30)
Some troubles with track quality cut.
– TkrTrack::getScatter() variable is used to select good quality track.
– It is wildly different with 16-tower data from any previous data.
– Cause is not understood yet.
8-tower data
16-tower data
Hiro Tajima, TKR 16-tower data
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GLAST LAT Project
LAT Instrument Analysis Meeting– Jan 20, 2006
Other differences
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Number of TKR recon clusters used for tracking.
(TkrTrack::numFitHits)
– We tend to have more hits used for 16-tower data.
Layer distribution of TKR recon clusters AFTER cut on
TkrTrack::getScatter()
– Top layer clusters are much enhanced after track quality cut.
8-tower data
16-tower data
Hiro Tajima, TKR 16-tower data
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GLAST LAT Project
LAT Instrument Analysis Meeting– Jan 20, 2006
Mitigation
• Calculate RMS from straight line fit.
– Small difference between 8- and 16-tower data.
– This is currently used.
• TkrTrack::getKalThetaRMS() variable.
– Recommned by Leon.
– Opposite trend from straight line RMS.
Hiro Tajima, TKR 16-tower data
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GLAST LAT Project
LAT Instrument Analysis Meeting– Jan 20, 2006
TOT calibration
• No major change in “charge scale” distribution.
Hiro Tajima, TKR 16-tower data
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GLAST LAT Project
LAT Instrument Analysis Meeting– Jan 20, 2006
Noise Flare
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Noise flare observed in bays 7, 10, 15
– Still within specification.
– Tower average strip occupancy
• 1.4E-6 – 2.0E-6 (typ.)
• 10.0E-6 (bay 7) < 5E-5
• Can be suppressed further
by truncating @16 hits/GTRC
– Layer occupancy
• 1 – 3% < 8%.
Hiro Tajima, TKR 16-tower data
Sugizaki
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