ElectronTransport.cxx

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// Copyright 2019-2020 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.
 
 
#include "TPCSimulation/ElectronTransport.h"
#include "TPCBase/CDBInterface.h"
 
#include <cmath>
 
using namespace o2::tpc;
using namespace o2::math_utils;
 
ElectronTransport::ElectronTransport() : mRandomGaus(), mRandomFlat(RandomRing<>::RandomType::Flat)
{
  updateParameters();
}
 
void ElectronTransport::updateParameters(float vdrift)
{
  mGasParam = &(ParameterGas::Instance());
  mDetParam = &(ParameterDetector::Instance());
  mVDrift = vdrift > 0 ? vdrift : mGasParam->DriftV;
}
 
GlobalPosition3D ElectronTransport::getElectronDrift(GlobalPosition3D posEle, float& driftTime)
{
  float driftl = mDetParam->TPClength - std::abs(posEle.Z());
  if (driftl < 0.01) {
    driftl = 0.01;
  }
  driftl = std::sqrt(driftl);
  const float sigT = driftl * mGasParam->DiffT;
  const float sigL = driftl * mGasParam->DiffL;
 
  GlobalPosition3D posEleDiffusion((mRandomGaus.getNextValue() * sigT) + posEle.X(),
                                   (mRandomGaus.getNextValue() * sigT) + posEle.Y(),
                                   (mRandomGaus.getNextValue() * sigL) + posEle.Z());
 
 
  if (posEle.Z() / posEleDiffusion.Z() < 0.f) {
    driftTime = getDriftTime(posEleDiffusion.Z(), -1.f);
    posEleDiffusion.SetZ(posEle.Z());
 
  } else {
    driftTime = getDriftTime(posEleDiffusion.Z());
  }
 
  return posEleDiffusion;
}
 
bool ElectronTransport::isCompletelyOutOfSectorCoarseElectronDrift(GlobalPosition3D posEle, const Sector& sector) const
{
  float driftl = mDetParam->TPClength - std::abs(posEle.Z());
  if (driftl < 0.01) {
    driftl = 0.01;
  }
  driftl = std::sqrt(driftl);
 
  const float threeSigmaT = 3.f * driftl * mGasParam->DiffT;
 
  auto& mapper = Mapper::instance();
  return mapper.isOutOfSector(posEle, sector, threeSigmaT);
}