G4LivermoreRayleighModel.cc

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// Author: Sebastien Incerti
//         31 March 2012
//         on base of G4LivermoreRayleighModel
//
 
#include "G4LivermoreRayleighModel.hh"
#include "G4SystemOfUnits.hh"
#include "G4RayleighAngularGenerator.hh"
#include "G4EmParameters.hh"
#include "G4AutoLock.hh"
 
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using namespace std;
namespace { G4Mutex LivermoreRayleighModelMutex = G4MUTEX_INITIALIZER; }
 
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G4PhysicsFreeVector* G4LivermoreRayleighModel::dataCS[] = {nullptr};
 
G4LivermoreRayleighModel::G4LivermoreRayleighModel()
  :G4VEmModel("LivermoreRayleigh"),maxZ(100),isInitialised(false)
{
  fParticleChange = nullptr;
  lowEnergyLimit  = 10 * CLHEP::eV; 
  
  SetAngularDistribution(new G4RayleighAngularGenerator());
  
  verboseLevel= 0;
  // Verbosity scale for debugging purposes:
  // 0 = nothing 
  // 1 = calculation of cross sections, file openings...
  // 2 = entering in methods
 
  if(verboseLevel > 0) 
  {
    G4cout << "G4LivermoreRayleighModel is constructed " << G4endl;
  }
 
}
 
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G4LivermoreRayleighModel::~G4LivermoreRayleighModel()
{
  if(IsMaster())
  {
    for(G4int i = 0; i <= maxZ; ++i)
    {
      if(dataCS[i])
      {
        delete dataCS[i];
        dataCS[i] = nullptr;
      }
    }
  }
}
 
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void G4LivermoreRayleighModel::Initialise(const G4ParticleDefinition* particle,
                      const G4DataVector& cuts)
{
  if (verboseLevel > 1) 
  {
    G4cout << "Calling Initialise() of G4LivermoreRayleighModel." << G4endl
       << "Energy range: "
       << LowEnergyLimit() / eV << " eV - "
       << HighEnergyLimit() / GeV << " GeV"
       << G4endl;
  }
 
  if(IsMaster()) {
    // Initialise element selector
    InitialiseElementSelectors(particle, cuts);
 
    // Access to elements
    char* path = std::getenv("G4LEDATA");
    const G4ElementTable* elemTable = G4Element::GetElementTable();
    size_t numElems                 = (*elemTable).size();
    for(size_t ie = 0; ie < numElems; ++ie)
    {
      const G4Element* elem = (*elemTable)[ie];
      const G4int Z         = std::min(maxZ, elem->GetZasInt());
      if(dataCS[Z] == nullptr)
      {
        ReadData(Z, path);
      }
    }
  }
  if(isInitialised) { return; }
  fParticleChange = GetParticleChangeForGamma();
  isInitialised = true;
}
 
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void G4LivermoreRayleighModel::InitialiseLocal(const G4ParticleDefinition*,
                           G4VEmModel* masterModel)
{
  SetElementSelectors(masterModel->GetElementSelectors());
}
 
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void G4LivermoreRayleighModel::ReadData(size_t Z, const char* path)
{
  if (verboseLevel > 1) 
  {
    G4cout << "Calling ReadData() of G4LivermoreRayleighModel" 
       << G4endl;
  }
 
  if(nullptr != dataCS[Z]) { return; }
  
  const char* datadir = path;
 
  if(datadir == nullptr)
  {
    datadir = std::getenv("G4LEDATA");
    if(datadir == nullptr)
    {
      G4Exception("G4LivermoreRayleighModelModel::ReadData()","em0006",
          FatalException,
          "Environment variable G4LEDATA not defined");
      return;
    }
  }
  dataCS[Z] = new G4PhysicsFreeVector();
    
  std::ostringstream ostCS;
  if(G4EmParameters::Instance()->LivermoreDataDir() == "livermore"){
    ostCS << datadir << "/livermore/rayl/re-cs-" << Z <<".dat";
  }else{
    ostCS << datadir << "/epics2017/rayl/re-cs-" << Z <<".dat";
  }
 
  std::ifstream finCS(ostCS.str().c_str());
  
  if( !finCS .is_open() ) 
  {
    G4ExceptionDescription ed;
    ed << "G4LivermoreRayleighModel data file <" << ostCS.str().c_str()
       << "> is not opened!" << G4endl;
    G4Exception("G4LivermoreRayleighModel::ReadData()","em0003",FatalException,
        ed,"G4LEDATA version should be G4EMLOW6.27 or later.");
    return;
  } 
  else 
  {
    if(verboseLevel > 3) { 
      G4cout << "File " << ostCS.str() 
         << " is opened by G4LivermoreRayleighModel" << G4endl;
    }
    dataCS[Z]->Retrieve(finCS, true);
  } 
}
 
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G4double G4LivermoreRayleighModel::ComputeCrossSectionPerAtom(
                                       const G4ParticleDefinition*,
                                             G4double GammaEnergy,
                                             G4double Z, G4double,
                                             G4double, G4double)
{
  if (verboseLevel > 1) 
  {
    G4cout << "G4LivermoreRayleighModel::ComputeCrossSectionPerAtom()" 
       << G4endl;
  }
 
  if(GammaEnergy < lowEnergyLimit) { return 0.0; }
  
  G4double xs = 0.0;
  G4int intZ = G4lrint(Z);
  if(intZ < 1 || intZ > maxZ) { return xs; }
 
  G4PhysicsFreeVector* pv = dataCS[intZ];
 
  // if element was not initialised
  // do initialisation safely for MT mode
  if(nullptr == pv) { 
    InitialiseForElement(0, intZ);
    pv = dataCS[intZ];
    if(nullptr == pv) { return xs; }
  }
 
  G4int n = pv->GetVectorLength() - 1;
  G4double e = GammaEnergy/MeV;
  if(e >= pv->Energy(n)) {
    xs = (*pv)[n]/(e*e);  
  } else if(e >= pv->Energy(0)) {
    xs = pv->Value(e)/(e*e);  
  }
 
  if(verboseLevel > 1)
  {
    G4cout  <<  "****** DEBUG: tcs value for Z=" << Z << " at energy (MeV)=" 
        << e << G4endl;
    G4cout  <<  "  cs (Geant4 internal unit)=" << xs << G4endl;
    G4cout  <<  "    -> first E*E*cs value in CS data file (iu) =" << (*pv)[0] 
        << G4endl;
    G4cout  <<  "    -> last  E*E*cs value in CS data file (iu) =" << (*pv)[n] 
        << G4endl;
    G4cout  <<  "*********************************************************" 
        << G4endl;
  }
  return xs;
}
 
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void G4LivermoreRayleighModel::SampleSecondaries(
                          std::vector<G4DynamicParticle*>*,
              const G4MaterialCutsCouple* couple,
              const G4DynamicParticle* aDynamicGamma,
              G4double, G4double)
{
  if (verboseLevel > 1) {
    G4cout << "Calling SampleSecondaries() of G4LivermoreRayleighModel" 
       << G4endl;
  }
  G4double photonEnergy0 = aDynamicGamma->GetKineticEnergy();
  
  // Select randomly one element in the current material
  const G4ParticleDefinition* particle =  aDynamicGamma->GetDefinition();
  const G4Element* elm = SelectRandomAtom(couple,particle,photonEnergy0);
  G4int Z = G4lrint(elm->GetZ());
 
  // Sample the angle of the scattered photon  
  G4ThreeVector photonDirection = 
    GetAngularDistribution()->SampleDirection(aDynamicGamma, 
                          photonEnergy0, 
                          Z, couple->GetMaterial());
  fParticleChange->ProposeMomentumDirection(photonDirection);
}
 
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void 
G4LivermoreRayleighModel::InitialiseForElement(const G4ParticleDefinition*, 
                           G4int Z)
{
  G4AutoLock l(&LivermoreRayleighModelMutex);
  if(nullptr == dataCS[Z]) { ReadData(Z); }
  l.unlock();
}
 
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