readFT0hits.C

// Copyright 2019-2025 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.

#if !defined(__CLING__) || defined(__ROOTCLING__)

#include "DataFormatsFIT/Triggers.h"
#include "DataFormatsFT0/Digit.h"
#include "DataFormatsFT0/HitType.h"
#include "SimulationDataFormat/MCEventHeader.h"
#include <TFile.h>
#include <TH1F.h>
#include <TH2F.h>
#include <TTree.h>
#include "DetectorsCommonDataFormats/DetID.h"
#include "DetectorsCommonDataFormats/DetectorNameConf.h"

#endif

void readFT0hits()
{

  // Create histograms
  TDirectory* cwd = gDirectory;
  gDirectory = 0x0;

  TH2F* hMultHit =
    new TH2F("hMultHits", "photons Hits ", 220, 0, 220, 500, 0, 5000);
  TH2F* hTimeHitA = new TH2F("hTimeAhit", "Time Hits", 220, 0, 220, 500, -1, 1);
  TH2F* hTimeHitC = new TH2F("hTimeChit", "Time Hits", 220, 0, 220, 200, -1, 1);
  TH2F* hMultDig =
    new TH2F("hMultDig", "amplitude  ", 220, 0, 220, 500, 0, 1000);
  TH2F* hPel = new TH2F("hPelDig", "N p.e. ", 220, 0, 220, 500, 0, 10000);
  TH2F* hXYA = new TH2F("hXYA", "X vs Y A side", 400, -20, 20, 400, -20, 20);
  TH2F* hXYC = new TH2F("hXYC", "X vs Y C side", 400, -20, 20, 400, -20, 20);
  TH1F* hZA = new TH1F("hZA", "Z A side", 200, 330, 340);
  TH1F* hZC = new TH1F("hZC", "Z C side", 200, -90, -80);

  gDirectory = cwd;

  using namespace o2::detectors;
  TFile* fhit = new TFile(o2::base::DetectorNameConf::getHitsFileName(DetID::FT0, "o2sim").c_str());
  TTree* hitTree = (TTree*)fhit->Get("o2sim");

  o2::dataformats::MCEventHeader* mcHeader = nullptr;
  /*  if (!hitTree->GetBranch("MCEventHeader.")) {
    LOG(fatal) << "Did not find MC event header in the input header file." <<
    FairLogger::endl;
    }*/
  hitTree->SetBranchAddress("MCEventHeader.", &mcHeader);

  std::vector<o2::ft0::HitType>* hitArray = nullptr;
  hitTree->SetBranchAddress("FT0Hit", &hitArray);
  Int_t nevH = hitTree->GetEntries(); // hits are stored as one event per entry
  // std::cout << "Found " << nevH << " events with hits " << std::endl;

  Double_t hit_time[240];
  Int_t countE[240];
  // Event ------------------------- LOOP
  for (Int_t ievent = 0; ievent < nevH; ievent++) {
    hitTree->GetEntry(ievent);
    ///* std::cout<<ievent<<" b"<<mcHeader->GetB()<<std::endl;
    for (int ii = 0; ii < 240; ii++) {
      countE[ii] = 0;
      hit_time[ii] = 0;
    }
    for (auto& hit : *hitArray) {
      Int_t detID = hit.GetDetectorID();
      hit_time[detID] = hit.GetTime();
      hTimeHitA->Fill(detID, hit_time[detID] - 11.04);
      hTimeHitC->Fill(detID, hit_time[detID] - 2.91);
      countE[detID]++;
      if (detID < 96) {
        hXYA->Fill(hit.GetX(), hit.GetY());
        hZA->Fill(hit.GetZ());
      } else {
        hXYC->Fill(hit.GetX(), hit.GetY());
        hZC->Fill(hit.GetZ());
      }
    }
    for (int ii = 0; ii < 220; ii++) {
      if (countE[ii] > 100) {
        hMultHit->Fill(ii, countE[ii]);
      }
    }
  }
  TFile* Hfile = new TFile("ft0_hits_pp.root", "RECREATE");
  printf("Writting histograms to root file \n");
  Hfile->cd();
  // Create a canvas, set the view range, show histograms
  //  TCanvas *c1 = new TCanvas("c1","Alice T0 Time ",400,10,600,600);
  hTimeHitA->Scale(1. / 250.);
  hTimeHitC->Scale(1. / 250.);
  hTimeHitA->Write();
  hTimeHitC->Write();
  hMultHit->Write();
  hXYA->Write();
  hXYC->Write();
  hZA->Write();
  hZC->Write();
} // end of macro