Pass8 tag calorimeter ghost with trigger diagnostic information

This page presents an attempt to use the trigger TEM diagnostic information to recognize calorimeter ghost signal.
Pass 8 Recon & Analysis Upgrades Weekly Meeting Agenda

Summary

Information available

• The TEM trigger diagnostic information provides trigger information on CalLo and CalHi per each layer end.
• From Sasha:

  The code example for accessing CAL diagnostic info I can recommend you is the algorithm from calibGenCAL package used for trigger thresholds measurement:
  /afs/slac/g/glast/users/chehtman/calibGenCAL_analysis/calibGenCAL/calibGenCAL-05-06-00/src/lib/Algs/LPATrigAlg.cxx
  The method
  LPATrigAlg::fillTrigBitArray()
  just extracts CAL trigger bits from a digi file and puts them into some local structure.

• As a reminder, CalLo is at 100 MeV and CalHi at 1 GeV.

Analysis

• Starting from Sasha's example, I wrote a piece of code that does the following:

1. open digi, recon, merit and relation files

2. reads digi to create two arrays of layer end trigger bits [tower][layer][face] , one for CalLo and one for CalHi

3. open recon and loop on clusters, then for each cluter
   1. open the corresponding crystal collection
   2. check if any crystal end has more than 100 MeV (or whatever other threshold)
   3. if any, then look if the corresponding layer end has a trigger bit set
   4. if not so, fill in a map of missing trigger bits and add 1 to a so called "cal ghost number"
4. for each cluster, the higher the ghost number, the higher the probability that it's a ghost... but it looks like that aobve 2, they're all ghosts.

• Basic version of the code: tagghosts.C

Ghost number and cluster classification