Transcript ppt

GLAST LAT Project
Instrument Analysis Meeting, 9 December 2005
TKR to CAL for 16 Towers
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[Review my IA Workshop #4 presentation if you like (14 July 2005).]
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I set out to do my usual TKR extrapolation to CAL study for the 16 tower
real & MC data, to check calibrations, look for problems, etc.
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Gave it 2.5 days, which wasn’t enough, because
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Merit now has Float_t in MC but still Double_t in data, that cost me a
day.
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I didn’t grok that the statistics are too low: e.g. for 423967 MC events,
only 15 to 40 per crystal after my selection of clean, vertical tracks.
Loosening criteria won’t necessarily gain me much.
(423967/16/8 = 2208, which could be enough, but any ACD hit triggers…)
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Data runs 135004857, 59 have 1.88 M events with TKR trigger. I
wind up with
per crystal.
David Smith
1
SLAC SVAC CAL calib at Bordeaux
GLAST LAT Project
Instrument Analysis Meeting, 9 December 2005
The Method
• Extrapolate TKR track to CAL and
predict which crystals get hit.
• Compare energy deposits, position
resolution with Monte Carlo.
• Use Tkr1EndPos, Dir
• Require:
TkrNumTracks == 1
Tkr1KalThetaMs < 0.03
Tkr1NumHits > 15
<2 MeV in adjacent crystals
Track must traverse top & bottom of
crystal (“V == 1”)
• Correct
energy for cosq.
David Smith
2
SLAC SVAC CAL calib at Bordeaux
GLAST LAT Project
Instrument Analysis Meeting, 9 December 2005
A new plot: fraction of events
where expected
energy deposit is absent, per crystal.
If <7 MeV, flag the event. Here, MC w. low stats.
David Smith
3
SLAC SVAC CAL calib at Bordeaux
GLAST LAT Project
Instrument Analysis Meeting, 9 December 2005
Other work in progress…
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Now have the CalTuple in my macros, am making landau’ s in ADC
counts as per NRL request. Aim to add LAC values to that plot.
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Amusing that it’s called CalTuple in MC but CalXtalRecTuple in data.
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Was asked to add histograms to my value versus channel index format,
it’s happening.
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In other words, getting ready for the real, big data taking.
David Smith
4
SLAC SVAC CAL calib at Bordeaux