Transcript ppt

IA Meeting – Dec 9,2005
GLAST LAT Project
Overview
•
Goal
– Study GEM variables in SVAC ntuple
– So far in Italy we have not used the GASU
» Came to SLAC to learn about the GEM variables and how the
trigger works
– Prepare for final LAT data analysis
– Instrument Analysis Workshop 6 (see Eduardo’s talk)
•
Data Runs used for this talk
– 8 tower data (validated run by SVAC)
– Run 135004431
» my reference for this talk
– 16 tower data (test run)
– Run 135004859
» there could be problems here since it is a test run
A. Caliandro
1
IA Meeting – Dec 9,2005
GLAST LAT Project
Number of Triggered Towers
Run 135004431
(8 tower data: 499893 events, 1803 s)
~78000/1803 = 43 Hz
~800/1803 = 0.44 Hz
(Trigger threshold ~ 100 MeV)
A. Caliandro
2
IA Meeting – Dec 9,2005
GLAST LAT Project
Number of towers triggered
Run 135004431
(8 tower data)
Most of the events
occur in 1 or 2
towers
1 Track
Events
Only TKR
triggers
TKR opens
trigger window
A. Caliandro
CAL opens
trigger window
3
IA Meeting – Dec 9,2005
GLAST LAT Project
Trigger Rate (16 tower data)
Run 135004859
(16 tower data, 942229 events in 1804s)
~ 80000/1800 = 44 Hz ! (as expected)
Log Scale
Linear Scale
A. Caliandro
4
IA Meeting – Dec 9,2005
GLAST LAT Project
Number of Triggered Towers (16 tower data)
Run 135004859
1 Track
Events
Only TKR
triggers
TKR opens
trigger window
CAL is not allowed to open the
trigger window for this test run
A. Caliandro
5
IA Meeting – Dec 9,2005
GLAST LAT Project
Summary
• Preliminary Look at Trigger rates for 16 towers
– agree with expectations
• Recommendation
– add this plot to the SVAC reports
• Future
– Plan to study GEM variables when LAT data is available
– will continue developing scripts using existing data
A. Caliandro
6