Overview

1
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 Eduardos
  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

2
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)
3
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
CAL opens trigger window
4
Trigger Rate (16 tower data)
Run 135004859 (16 tower data, 942229 events in
1804s)
80000/1800 44 Hz ! (as expected)
Log Scale
Linear Scale
5
Number of Triggered Towers (16 tower data)
Run 135004859
1 Track Events
Only TKR triggers
CAL is not allowed to open the trigger window
for this test run
TKR opens trigger window
6
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