OpDigiProperties.cc

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//
//  \file OpDigiProperties_service.cc
//

// LArSoft includes
#include "larana/OpticalDetector/OpDigiProperties.h"

// Framework includes
#include "messagefacility/MessageLogger/MessageLogger.h"

// CLHEP includes
#include "CLHEP/Random/RandGauss.h"

// ROOT includes
#include "TF1.h"

// C++ includes
#include <fstream>

namespace opdet {

  //--------------------------------------------------------------------
  OpDigiProperties::OpDigiProperties(fhicl::ParameterSet const& p) : fAnalyticalSPE(0)
  {
    fSampleFreq = p.get<double>("SampleFreq");
    fTimeBegin = p.get<double>("TimeBegin");
    fTimeEnd = p.get<double>("TimeEnd");
    fWaveformFile = p.get<std::string>("WaveformFile");
    fPERescale = p.get<double>("PERescale");

    // PMT properties
    fQE = p.get<double>("QE");
    fDarkRate = p.get<double>("DarkRate");
    fSaturationScale = p.get<optdata::ADC_Count_t>("SaturationScale");

    // Shaper properties
    fUseEmpiricalGain = p.get<bool>("UseEmpiricalGain");
    fHighGainFile = p.get<std::string>("HighGainFile");
    fLowGainFile = p.get<std::string>("LowGainFile");
    fGainSpreadFile = p.get<std::string>("GainSpreadFile");

    fHighGainMean = p.get<double>("HighGainMean");
    fLowGainMean = p.get<double>("LowGainMean");
    fGainSpread = p.get<double>("GainSpread");
    fGainSpread_PMT2PMT = p.get<double>("GainSpread_PMT2PMT");

    // Digitization ped fluc
    fPedFlucRate = p.get<double>("PedFlucRate");
    fPedFlucAmp = p.get<optdata::ADC_Count_t>("PedFlucAmp");
    fADCBaseline = p.get<optdata::ADC_Count_t>("ADCBaseline");
    fADCBaseSpread = p.get<double>("ADCBaseSpread");

    // WF related stuff
    fUseEmpiricalShape = p.get<bool>("UseEmpiricalShape");
    fWFLength = p.get<double>("WFLength");

    fWaveformFile = p.get<std::string>("WaveformFile");
    fChargeNormalized = p.get<bool>("WaveformChargeNormalized", false);

    // Option 2: WF from analytical function
    fWFPowerFactor = p.get<double>("WFPowerFactor");
    fWFTimeConstant = p.get<double>("WFTimeConstant");
    fVoltageAmpForSPE = p.get<double>("VoltageAmpForSPE");

    // Generate the SPE waveform (i.e. fWaveform)
    GenerateWaveform();

    // Fill gain array
    FillGainArray();

    // Fill baseline mean
    FillPedMeanArray();

    // Report
    std::string msg(Form(
      "%-10s ... %-10s ... %-10s ... %-10s\n", "Ch. Number", "Pedestal", "High Gain", "Low Gain"));
    for (unsigned int i = 0; i < fGeometry->NOpChannels(); ++i) {
      msg += Form("%-10d ... %-10d ... %-10g ... %-10g\n",
                  i,
                  fPedMeanArray[i],
                  fHighGainArray[i],
                  fLowGainArray[i]);
    }
    mf::LogInfo(__FUNCTION__) << msg.c_str();
  }

  //--------------------------------------------------------------------
  double OpDigiProperties::GetSPEArea()
  {
    double SPEArea = 0;
    for (size_t i = 0; i != fWaveform.size(); ++i)
      SPEArea += fWaveform.at(i);
    return SPEArea;
  }

  //--------------------------------------------------------------------
  double OpDigiProperties::GetSPEAmplitude()
  {
    double AmpSoFar = 0;
    for (size_t i = 0; i != fWaveform.size(); ++i)
      if (fWaveform.at(i) > AmpSoFar) AmpSoFar = fWaveform.at(i);
    return AmpSoFar;
  }

  //--------------------------------------------------------------------
  double OpDigiProperties::GetSPECumulativeArea()
  {
    double Cumulative = 0, SPEArea = 0;
    for (size_t i = 0; i != fWaveform.size(); ++i) {
      Cumulative += fWaveform.at(i);
      SPEArea += Cumulative;
    }
    return SPEArea;
  }

  //--------------------------------------------------------------------
  double OpDigiProperties::GetSPECumulativeAmplitude()
  {
    double AmpSoFar = 0, Cumulative = 0;
    for (size_t i = 0; i != fWaveform.size(); ++i) {
      Cumulative += fWaveform.at(i);
      if (Cumulative > AmpSoFar) AmpSoFar = Cumulative;
    }
    return AmpSoFar;
  }

  //--------------------------------------------------------------------

  double OpDigiProperties::LowGainMean(optdata::Channel_t ch) const
  {
    return fLowGainArray[ch];
  }

  //--------------------------------------------------------------------
  double OpDigiProperties::HighGainMean(optdata::Channel_t ch) const
  {
    return fHighGainArray[ch];
  }
  //--------------------------------------------------------------------
  double OpDigiProperties::LowGain(optdata::Channel_t ch) const
  {
    return CLHEP::RandGauss::shoot(fLowGainArray[ch], fGainSpreadArray[ch] * fLowGainArray[ch]);
  }
  //--------------------------------------------------------------------
  double OpDigiProperties::HighGain(optdata::Channel_t ch) const
  {
    return CLHEP::RandGauss::shoot(fHighGainArray[ch], fGainSpreadArray[ch] * fHighGainArray[ch]);
  }
  //--------------------------------------------------------------------
  optdata::TimeSlice_t OpDigiProperties::GetTimeSlice(double time_ns)
  {
    if (time_ns / 1.e3 > (fTimeEnd - fTimeBegin))
      return std::numeric_limits<optdata::TimeSlice_t>::max();

    else
      return optdata::TimeSlice_t((time_ns / 1.e3 - fTimeBegin) * fSampleFreq);
  }

  //
  // As far as Kazu is concerned, this function is deprecated.
  // Any comment? --Kazu 08/05/2013
  //
  std::vector<double> OpDigiProperties::WaveformInit(std::string fWaveformFile)
  {
    // Read in waveform vector from text file
    std::ifstream WaveformFile(fWaveformFile.c_str());
    std::string line;

    mf::LogInfo("OpDigiProperties")
      << "OpDigiProperties opening OpDet waveform at " << fWaveformFile.c_str();

    // Read in each line and place into waveform vector
    std::vector<double> PEWaveform;
    if (WaveformFile.is_open()) {
      while (WaveformFile.good()) {
        getline(WaveformFile, line);
        PEWaveform.push_back(fPERescale * strtod(line.c_str(), NULL));
      }
    }
    else
      throw cet::exception("OpDigiProperties") << "No Waveform File: Unable to open file\n";

    WaveformFile.close();
    return (PEWaveform);
  }

  // Fill the array of pedestal mean
  void OpDigiProperties::FillPedMeanArray()
  {
    for (unsigned int i = 0; i < fGeometry->NOpChannels(); ++i)
      fPedMeanArray.push_back((optdata::ADC_Count_t)(
        CLHEP::RandGauss::shoot((double)fADCBaseline, fADCBaseSpread) + 0.5));
  }

  // Fill arrays (std::vector<double>) for PMT gain mean & spread information.
  void OpDigiProperties::FillGainArray()
  {
    if (fUseEmpiricalGain) {
      // Fill fron user's text files.
      mf::LogWarning("OpDigiProperties") << "Using empirical table of gain for each PMT...";
      std::string FullPath;
      cet::search_path sp("FW_SEARCH_PATH");

      if (!sp.find_file(fHighGainFile, FullPath))
        throw cet::exception("OpDigiProperties")
          << "Unable to find high gain spread file in " << sp.to_string() << "\n";

      mf::LogWarning("OpDigiProperties")
        << "OpDigiProperties opening high gain spread file at " << FullPath.c_str();
      std::ifstream HighGainFile(FullPath.c_str());
      if (HighGainFile.is_open()) {
        std::string line;
        while (HighGainFile.good()) {
          getline(HighGainFile, line);
          fHighGainArray.push_back(strtod(line.c_str(), NULL));
        }
      }
      else
        throw cet::exception("OpDigiProperties") << "Unable to open file!\n";

      FullPath = "";
      if (!sp.find_file(fLowGainFile, FullPath))
        throw cet::exception("OpDigiProperties")
          << "Unable to find low gain spread file in " << sp.to_string() << "\n";

      mf::LogWarning("OpDigiProperties")
        << "OpDigiProperties opening low gain spread file at " << FullPath.c_str();
      std::ifstream LowGainFile(FullPath.c_str());
      if (LowGainFile.is_open()) {
        std::string line;
        while (LowGainFile.good()) {
          getline(LowGainFile, line);
          fLowGainArray.push_back(strtod(line.c_str(), NULL));
        }
      }
      else
        throw cet::exception("OpDigiProperties") << "Unable to open file!\n";

      FullPath = "";
      if (!sp.find_file(fGainSpreadFile, FullPath))
        throw cet::exception("OpDigiProperties")
          << "Unable to find low gain spread file in " << sp.to_string() << "\n";

      mf::LogWarning("OpDigiProperties")
        << "OpDigiProperties opening low gain spread file at " << FullPath.c_str();
      std::ifstream GainSpreadFile(FullPath.c_str());
      if (GainSpreadFile.is_open()) {
        std::string line;
        while (GainSpreadFile.good()) {
          getline(GainSpreadFile, line);
          fGainSpreadArray.push_back(strtod(line.c_str(), NULL));
        }
      }
      else
        throw cet::exception("OpDigiProperties") << "Unable to open file!\n";
    }
    else {
      // Generate a set of gake gain mean & spread.
      std::string txt;
      txt += "    Generating gain for each pmt.\n";
      txt += Form("        High gain mean: %g ADC/p.e.\n", fHighGainMean);
      txt += Form("        Low  gain mean: %g ADC/p.e.\n", fLowGainMean);
      txt += Form("        PMT-to-PMT gain spread : %g \n", fGainSpread_PMT2PMT);
      txt += Form("        Intrinsic gain spread  : %g \n", fGainSpread);
      mf::LogWarning("OpDigiProperties") << txt.c_str();
      for (unsigned int i = 0; i < fGeometry->NOpChannels(); ++i) {
        fLowGainArray.push_back(
          CLHEP::RandGauss::shoot(fLowGainMean, fLowGainMean * fGainSpread_PMT2PMT));
        fHighGainArray.push_back(
          CLHEP::RandGauss::shoot(fHighGainMean, fHighGainMean * fGainSpread_PMT2PMT));
        fGainSpreadArray.push_back(fGainSpread);
      }
    }

    //
    // Note:
    // Check for # entries. These exceptions ensures we have enough # of elements.
    // When a user access the elements by a channel number using LowGainMean(Channel_t ch) etc.,
    // those functions do not check if the given channel number is valid or not to keep a high
    // performance of the code. If there's an invalid memory access error in run-time, then
    // it must mean the user provided an invalid channel number and not due to insufficient
    // vector elements filled in this function.
    //
    if (fLowGainArray.size() < fGeometry->NOpChannels())
      throw cet::exception("OpDigiProperties") << "Low gain missing for some channels!\n";
    if (fHighGainArray.size() < fGeometry->NOpChannels())
      throw cet::exception("OpDigiProperties") << "High gain missing for some channels!\n";
    if (fGainSpreadArray.size() < fGeometry->NOpChannels())
      throw cet::exception("OpDigiProperties") << "Gain spread missing for some channels!\n";
  }

  void OpDigiProperties::GenerateWaveform()
  {
    std::string FullPath;

    if (fUseEmpiricalShape) {
      cet::search_path sp("FW_SEARCH_PATH");
      if (!sp.find_file(fWaveformFile, FullPath))

        throw cet::exception("OpDigiProperties")
          << "Unable to find PMT waveform file in " << sp.to_string() << "\n";

      fWaveform = GenEmpiricalWF(FullPath);
    }
    else
      fWaveform = GenAnalyticalWF();
  }

  std::vector<double> OpDigiProperties::GenEmpiricalWF(std::string fWaveformFile)
  {
    // Read in waveform vector from text file
    std::ifstream WaveformFile(fWaveformFile.c_str());
    std::string line;

    mf::LogWarning("OpDigiProperties")
      << "OpDigiProperties opening OpDet waveform at " << fWaveformFile.c_str();

    // Read in each line and place into waveform vector
    std::vector<double> PEWaveform;
    if (WaveformFile.is_open()) {
      double MaxAmp = 0;
      double Charge = 0;
      int NSample = 0;
      while (WaveformFile.good() && NSample < int(fWFLength * fSampleFreq)) {
        getline(WaveformFile, line);
        double Amp = strtod(line.c_str(), NULL);
        PEWaveform.push_back(Amp);
        if (Amp > MaxAmp) MaxAmp = Amp;
        NSample++;
        Charge += Amp;
      }
      // rescale
      if (MaxAmp <= 0)
        throw cet::exception("OpDigiProperties_module") << "Waveform amplitude <=0!\n";
      if (!fChargeNormalized)
        for (unsigned short i = 0; i < PEWaveform.size(); i++) {
          PEWaveform[i] = PEWaveform[i] / MaxAmp;
        }
      else
        for (unsigned short i = 0; i < PEWaveform.size(); i++) {
          PEWaveform[i] = PEWaveform[i] / Charge;
        }
    }
    else
      throw cet::exception("No Waveform File") << "Unable to open file\n";

    WaveformFile.close();
    return (PEWaveform);
  }

  std::vector<double> OpDigiProperties::GenAnalyticalWF()
  {
    mf::LogWarning("OpDigiProperties")
      << "    OpDigiProperties using analytical function for WF generation.";
    //
    // Generate waveform from analytical form
    //
    if (!fAnalyticalSPE) { // Create analytical function if not yet created
      fAnalyticalSPE = new TF1("_analyticalSPE",
                               "10^(22)*x^[1]*[0]*exp(-x/[2])/TMath::Factorial([1])",
                               0,
                               fWFLength * 2);            // x is time in micro-seconds
      fAnalyticalSPE->SetParameter(0, fVoltageAmpForSPE); // voltage amplitude for s.p.e.
      fAnalyticalSPE->SetParameter(1, fWFPowerFactor);    // power factor (no unit)
      fAnalyticalSPE->SetParameter(2, fWFTimeConstant);   // time constant in us
    }
    //
    // Define a waveform vector
    //
    // Size of WF = time width [us] * frequency [MHz]
    std::vector<double> PEWaveform(int(fWFLength * fSampleFreq), 0.0);
    double SamplingDuration = 1. / fSampleFreq; // in micro seconds
    double MaxAmp = 0;
    double Charge = 0;
    for (unsigned short i = 0; i < PEWaveform.size(); ++i) {
      double Value = fAnalyticalSPE->Integral(i * SamplingDuration, (i + 1) * SamplingDuration) /
                     SamplingDuration;
      PEWaveform[i] = Value;
      if (PEWaveform[i] > MaxAmp) MaxAmp = PEWaveform[i];
      Charge += Value;
    }

    // rescale
    if (MaxAmp <= 0) throw cet::exception("OpDigiProperties_module") << "Waveform amplitude <=0!\n";

    if (!fChargeNormalized) {
      for (unsigned short i = 0; i < PEWaveform.size(); i++) {
        PEWaveform[i] = PEWaveform[i] / MaxAmp;
        if (PEWaveform[i] < 1.e-4) PEWaveform[i] = 0;
      }
    }
    else
      for (unsigned short i = 0; i < PEWaveform.size(); i++) {
        PEWaveform[i] = PEWaveform[i] / Charge;
      }

    return PEWaveform;
  }

} // namespace