Accessing Photodetector Data in LArIATSoft¶
Data from the PMTs and SiPMs are stored as raw::OpDetPulse objects by LArSoft. You can read more about this class here.
There is a well-commented tutorial,
LArIATAnaModule/OpDetExample_module.cc, which goes over the basics of accessing this data, finding hits, and integrating pulses. It uses functions from the custom
OpHitBuilderAlg class, many of which are still being actively developed and improved. Feel free to look through these algorithms in
LArIATRecoAlg/OpHitBuilderAlg.cxx, or use them as templates for new functions that better suit your needs.
To run the program, after building lariatsoft (v05_10_00 or higher), do
lar -c OpDetExample.fcl -s /pnfs/lariat/data/digit/001/162/lariat_digit_r006250_sr0050_20160125T013008.root
This will produce an output file
OpDetExample_histo.root containing some histograms and an averaged waveform of optical hits found in the beam window for subrun 50 in run 6250 (Run 1 pre-digitized data). Some individual waveforms for the specified photodetector will also be saved to the output file in the form of TH1F histograms.
Once you have a good grasp of how everything works, you can create your own analysis module, preferably in a new feature branch separate from
origin/develop, by doing
artmod -A analyzer MyNewModule
You can copy some of the code from
OpDetExample_module.cc to get started, and then build on it from there to do the analysis that you want.