C++ Stand-alone library for Merging, Digitizing, and Triggering hits of photomultiplier tubes (PMTs) based on WCSim. A Python interface is optionally provided, requiring pre-installation of pybind11.

The library provides C++ classes that manage three tasks:

• Merging true hits (simulated photoelectrons by WCSim) of an events with those of any number of events
  • Intrinsic dark noise can be added during this stage
• Digitizing true hits
  • Timing and charge of a digitized hit is simulated by a simple model used in WCSim
  • The library is capable of accomodating alternative models
  • Parameters describing PMT charcteristics such as timing resolution can be varied
  • Digitized hits by PMT afterpusing can be added
• Triggering digitized hits
  • A simple algorithm that counts number of digitized hits falling in a sliding time winodw
  • Selectable trigger window and thershold

For details, check doc/MDT.md.

Simple runtime procedures. First set up your ROOT and WCSIM:

source your_thisroot.sh
source your_this_wcsim.sh # or just export WCSIM_BUILD_DIR

Then set up the MDT environment.

source envMDT.sh
cd $MDTROOT/cpp; make clean; make all
cd $MDTROOT/app/utilities/WCRootData; make clean; make all
cd $MDTROOT/app/application; make clean; make all
cd $MDTROOT
# edit variables properly in run_test_mdt4wcte.sh
bash run_test_mdt4wcte.sh

Essentially the same usage but with OD support.

# edit variables properly in run_test_mdt4iwcd.sh
bash run_test_mdt4iwcd.sh

Example usage

$MDTROOT/app/application/appGenPileUpSpill $MDTROOT/example/genPileUpConfig.txt

The application generates pile-up events by combining ID neutrino interaction events and beam background events in a spill.

Input variables are:

• ListIDNuIntFiles,ListBeamBkgFiles: list of WCSim output files for the ID and background events
• OutFileNamePrefix: output file name will be something like "OutFileNamePrefix".00000.root
• MDTParFile: MDT config file
• InitialSeed: Random seed
• IDNuIntRate,BeamBkgRate: Mean number of ID and background events per spill. In each spill, the actual number of interactions are drawn from a Poisson distribution, and interaction timing according to the bunch structure (see BeamTiming class under app/utilities/WCRootData/)
• UseOD: Process OD hits
• NumOfSpillsSavedPerFile, TotalNumOfSpills: output spill setup

Turn on waveform simulation in the parameter file by < DigitizerType_PMTType = 1 >.

For each true hit, a digitized waveform is simulated by sampling the single PE pulse (defined by the < WaveformFile > parameter) every 8 ns with 0.1 resolution. If there is another PE arriving within the hit integration window, the waveforms are added.

To do pulse fitting, the hit finding algorithm here is implemented to calculate the digitized time and charge.

Optionally, the waveform and digi TQ pulls of the first pulse of each PMT in each event can be saved by setting < SaveWaveform = 1 >. To read the pulses,

// open the file and get the digitzed waveform tree
TTree* wcsimDigiWFTree = (TTree*)f->Get("wcsimDigiWFTree");
TClonesArray *arr = new TClonesArray("TH1F");
wcsimDigiWFTree->GetBranch("wcsimrootevent_waveform")->SetAutoDelete(kFALSE);
wcsimDigiWFTree->SetBranchAddress("wcsimrootevent_waveform",&arr);
// In each event, each array index corresponds to PMTId-1 (from 0 to nPMTs-1)
wcsimDigiWFTree->GetEntry(0); // EvtId
TH1F* h = (TH1F*)arr->At(0); // PMTId-1
// Time and charge pulls of digitized hits
TTree* WCSimDigiPulls = (TTree*)f->Get("WCSimDigiPulls");
WCSimDigiPulls->Scan("PullT:TrueT:PullQ:TrueQ:EvtId:PMTId","PullT>-99"); // Pull==-99 means no digi hit for this PMT in this event