geant4/source/processes/electromagnetic/lowenergy/src/G4LivermoreGammaConversion5DModel.cc

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// Author: Zhuxin Li@CENBG
//         11 March 2020
//         on the base of G4LivermoreGammaConversionModel 
//         derives from G4BetheHeitler5DModel              
// -------------------------------------------------------------------

#include "G4LivermoreGammaConversion5DModel.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4EmParameters.hh"
#include "G4ParticleChangeForGamma.hh"
#include "G4LPhysicsFreeVector.hh"
#include "G4PhysicsLogVector.hh"
#include "G4ProductionCutsTable.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4Exp.hh"

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G4double G4LivermoreGammaConversion5DModel::lowEnergyLimit = 2.*CLHEP::electron_mass_c2;
G4int G4LivermoreGammaConversion5DModel::verboseLevel = 0;
constexpr G4int G4LivermoreGammaConversion5DModel::maxZ;
G4LPhysicsFreeVector* G4LivermoreGammaConversion5DModel::data[] = {nullptr};

G4LivermoreGammaConversion5DModel::G4LivermoreGammaConversion5DModel(const G4ParticleDefinition* p, 
const G4String& nam)
: G4BetheHeitler5DModel(p, nam), fParticleChange(nullptr)
{
  // Verbosity scale for debugging purposes:
  // 0 = nothing 
  // 1 = calculation of cross sections, file openings...
  // 2 = entering in methods
  if(verboseLevel > 0) 
  {
    G4cout << "G4LivermoreGammaConversion5DModel is constructed " << G4endl;
  }
}

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G4LivermoreGammaConversion5DModel::~G4LivermoreGammaConversion5DModel()
{
  if(IsMaster()) {
    for(G4int i=0; i<maxZ; ++i) {
      if(data[i]) { 
	      delete data[i];
	      data[i] = nullptr;
      }
    }
  }
}

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void 
G4LivermoreGammaConversion5DModel::Initialise( const G4ParticleDefinition* particle,
				                                     const G4DataVector& cuts)
{
 G4BetheHeitler5DModel::Initialise(particle, cuts);
   
  if (verboseLevel > 1) 
  {
    G4cout << "Calling Initialise() of G4LivermoreGammaConversion5DModel." 
	   << G4endl
	   << "Energy range: "
	   << LowEnergyLimit() / MeV << " MeV - "
	   << HighEnergyLimit() / GeV << " GeV isMater: " << IsMaster() 
	   << G4endl;
  }

  if(!fParticleChange) {
    fParticleChange = GetParticleChangeForGamma();
  }

  if(IsMaster()) 
  {
    // Initialise element selector
    InitialiseElementSelectors(particle, cuts);
    // Access to elements
    char* path = std::getenv("G4LEDATA");
    G4ProductionCutsTable* theCoupleTable =
       G4ProductionCutsTable::GetProductionCutsTable();
    G4int numOfCouples = theCoupleTable->GetTableSize();
    for(G4int i=0; i<numOfCouples; ++i) 
    {
      const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple(i);
      SetCurrentCouple(couple);
      const G4Material* mat = couple->GetMaterial();
      const G4ElementVector* theElementVector = mat->GetElementVector();
      G4int nelm = mat->GetNumberOfElements();
      for (G4int j=0; j<nelm; ++j) 
      {
        G4int Z = std::max(1, std::min((*theElementVector)[j]->GetZasInt(), maxZ));
        if(!data[Z]) { ReadData(Z, path); }
      }
    }
  }
}

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void G4LivermoreGammaConversion5DModel::ReadData(size_t Z, const char* path)
{
  if (verboseLevel > 1) 
  {
    G4cout << "Calling ReadData() of G4LivermoreGammaConversion5DModel" 
	   << G4endl;
  }
  
  if(data[Z]) { return; }
  const char* datadir = path;
  if(!datadir) 
  {
    datadir = std::getenv("G4LEDATA");
    if(!datadir) 
    {
      G4Exception("G4LivermoreGammaConversion5DModel::ReadData()",
		  "em0006",FatalException,
		  "Environment variable G4LEDATA not defined");
      return;
    }
  }
  data[Z] = new G4LPhysicsFreeVector();
  std::ostringstream ost;
  ost << datadir << "/epics2017/pair/pp-cs-" << Z <<".dat";
  std::ifstream fin(ost.str().c_str());
  
  if( !fin.is_open()) 
  {
    G4ExceptionDescription ed;
    ed << "G4LivermoreGammaConversion5DModel data file <" << ost.str().c_str()
       << "> is not opened!" << G4endl;
    G4Exception("G4LivermoreGammaConversion5DModel::ReadData()",
		"em0003",FatalException,
		ed,"G4LEDATA version should be G4EMLOW6.27 or later.");
    return;
  }   
  else 
  {
    if(verboseLevel > 1) { G4cout << "File " << ost.str() 
	     << " is opened by G4LivermoreGammaConversion5DModel" << G4endl;} 
    data[Z]->Retrieve(fin, true);
  } 
  // Activation of linear interpolation   
  data[Z]->SetSpline(false); // EPICS2017 has more points -> linear is fine
}

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G4double 
G4LivermoreGammaConversion5DModel::ComputeCrossSectionPerAtom(
   const G4ParticleDefinition* particle, G4double GammaEnergy, G4double Z, 
   G4double, G4double, G4double)
{
  if (verboseLevel > 1) 
  {
    G4cout << "G4LivermoreGammaConversion5DModel::ComputeCrossSectionPerAtom() Z= " 
	   << Z << G4endl;
  }
  G4double xs = 0.0;
  if (GammaEnergy < lowEnergyLimit) { return xs; } 
  
  G4int intZ = std::max(1, std::min(G4lrint(Z), maxZ));
  G4LPhysicsFreeVector* pv = data[intZ];
  // if element was not initialised
  // do initialisation safely for MT mode
  if(!pv) 
  {
    InitialiseForElement(particle, intZ);
    pv = data[intZ];
    if(!pv) { return xs; }
  }
  // x-section is taken from the table
  xs = pv->Value(GammaEnergy); 
  if(verboseLevel > 0)
  {
    G4cout  <<  "*** Gamma conversion xs for Z=" << Z << " at energy E(MeV)=" 
	    << GammaEnergy/MeV <<  "  cs=" << xs/millibarn << " mb" << G4endl;
  }
  return xs;
}

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#include "G4AutoLock.hh"
namespace { G4Mutex LivermoreGammaConversion5DModelMutex = G4MUTEX_INITIALIZER; }

void G4LivermoreGammaConversion5DModel::InitialiseForElement(
				      const G4ParticleDefinition*, 
				      G4int Z)
{
  G4AutoLock l(&LivermoreGammaConversion5DModelMutex);
  //  G4cout << "G4LivermoreGammaConversion5DModel::InitialiseForElement Z= " 
  //   << Z << G4endl;
  if(!data[Z]) { ReadData(Z); }
  l.unlock();
}

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