G4LivermoreGammaConversionModel.cc

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//
// Author: Sebastien Incerti
//         22 January 2012
//         on base of G4LivermoreGammaConversionModel (original version)
//         and G4LivermoreRayleighModel (MT version)
//
// Modifications: Zhuxin Li@CENBG
//                11 March 2020
//                derives from G4PairProductionRelModel               
// -------------------------------------------------------------------
 
#include "G4LivermoreGammaConversionModel.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 G4LivermoreGammaConversionModel::lowEnergyLimit = 2.*CLHEP::electron_mass_c2;
G4int G4LivermoreGammaConversionModel::verboseLevel = 0;
constexpr G4int G4LivermoreGammaConversionModel::maxZ; 
G4LPhysicsFreeVector* G4LivermoreGammaConversionModel::data[] = {nullptr};
 
G4LivermoreGammaConversionModel::G4LivermoreGammaConversionModel
(const G4ParticleDefinition* p, const G4String& nam)
: G4PairProductionRelModel(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 << "G4LivermoreGammaConversionModel is constructed " << G4endl;
  }
}
 
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G4LivermoreGammaConversionModel::~G4LivermoreGammaConversionModel()
{
  if(IsMaster()) {
    for(G4int i=0; i<maxZ; ++i) {
      if(data[i]) { 
    delete data[i];
    data[i] = nullptr;
      }
    }
  }
}
 
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void G4LivermoreGammaConversionModel::Initialise(
                                const G4ParticleDefinition* particle,
                const G4DataVector& cuts)
{ G4PairProductionRelModel::Initialise(particle, cuts);
  if (verboseLevel > 1) 
  {
    G4cout << "Calling Initialise() of G4LivermoreGammaConversionModel." 
       << 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::min((*theElementVector)[j]->GetZasInt(), maxZ);
        if(!data[Z]) { ReadData(Z, path); }
      }
    }
  }
}
 
 
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void G4LivermoreGammaConversionModel::ReadData(size_t Z, const char* path)
{
  if (verboseLevel > 1) 
  {
    G4cout << "Calling ReadData() of G4LivermoreGammaConversionModel" 
       << G4endl;
  }
 
  if(data[Z]) { return; }
  
  const char* datadir = path;
 
  if(!datadir) 
  {
    datadir = std::getenv("G4LEDATA");
    if(!datadir) 
    {
      G4Exception("G4LivermoreGammaConversionModel::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 << "G4LivermoreGammaConversionModel data file <" << ost.str().c_str()
       << "> is not opened!" << G4endl;
    G4Exception("G4LivermoreGammaConversionModel::ReadData()",
        "em0003",FatalException,
        ed,"G4LEDATA version should be G4EMLOW6.27 or later.");
    return;
  }   
  else 
  {
    
    if(verboseLevel > 1) { G4cout << "File " << ost.str() 
         << " is opened by G4LivermoreGammaConversionModel" << 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 G4LivermoreGammaConversionModel::ComputeCrossSectionPerAtom(
           const G4ParticleDefinition* particle,
       G4double GammaEnergy, G4double Z, G4double, G4double, G4double)
{
  if (verboseLevel > 1) 
  {
    G4cout << "G4LivermoreGammaConversionModel::ComputeCrossSectionPerAtom() Z= " 
       << Z << G4endl;
  }
 
  if (GammaEnergy < lowEnergyLimit) { return 0.0; } 
 
  G4double xs = 0.0;
  
  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 LivermoreGammaConversionModelMutex = G4MUTEX_INITIALIZER; }
 
void G4LivermoreGammaConversionModel::InitialiseForElement(
                      const G4ParticleDefinition*, 
                      G4int Z)
{
  G4AutoLock l(&LivermoreGammaConversionModelMutex);
  //  G4cout << "G4LivermoreGammaConversionModel::InitialiseForElement Z= " 
  //   << Z << G4endl;
  if(!data[Z]) { ReadData(Z); }
  l.unlock();
}
 
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