G4VEmModel.cc

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// $Id$
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4VEmModel
//
// Author:        Vladimir Ivanchenko
//
// Creation date: 25.07.2005
//
// Modifications:
// 25.10.2005 Set default highLimit=100.TeV (V.Ivanchenko)
// 06.02.2006 add method ComputeMeanFreePath() (mma)
// 16.02.2009 Move implementations of virtual methods to source (VI)
//
//
// Class Description:
//
// Abstract interface to energy loss models

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

#include "G4VEmModel.hh"
#include "G4LossTableManager.hh"
#include "G4ProductionCutsTable.hh"
#include "G4ParticleChangeForLoss.hh"
#include "G4ParticleChangeForGamma.hh"

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G4VEmModel::G4VEmModel(const G4String& nam):
  flucModel(0),anglModel(0), name(nam), lowLimit(0.1*CLHEP::keV), 
  highLimit(100.0*CLHEP::TeV),eMinActive(0.0),eMaxActive(DBL_MAX),
  polarAngleLimit(CLHEP::pi),secondaryThreshold(DBL_MAX),
  theLPMflag(false),flagDeexcitation(false),flagForceBuildTable(false),
  pParticleChange(0),xSectionTable(0),theDensityFactor(0),theDensityIdx(0),
  fCurrentCouple(0),fCurrentElement(0),
  nsec(5) 
{
  xsec.resize(nsec);
  nSelectors = 0;
  G4LossTableManager::Instance()->Register(this);
}

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G4VEmModel::~G4VEmModel()
{
  G4LossTableManager::Instance()->DeRegister(this);
  G4int n = elmSelectors.size();
  if(n > 0) {
    for(G4int i=0; i<n; ++i) { 
      delete elmSelectors[i]; 
    }
  }
  delete anglModel;
  if(xSectionTable) { 
    xSectionTable->clearAndDestroy(); 
    delete xSectionTable;
  }
}

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G4ParticleChangeForLoss* G4VEmModel::GetParticleChangeForLoss()
{
  G4ParticleChangeForLoss* p = 0;
  if (pParticleChange) {
    p = static_cast<G4ParticleChangeForLoss*>(pParticleChange);
  } else {
    p = new G4ParticleChangeForLoss();
    pParticleChange = p;
  }
  return p;
}

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G4ParticleChangeForGamma* G4VEmModel::GetParticleChangeForGamma()
{
  G4ParticleChangeForGamma* p = 0;
  if (pParticleChange) {
    p = static_cast<G4ParticleChangeForGamma*>(pParticleChange);
  } else {
    p = new G4ParticleChangeForGamma();
    pParticleChange = p;
  }
  return p;
}

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void G4VEmModel::InitialiseElementSelectors(const G4ParticleDefinition* p, 
                                            const G4DataVector& cuts)
{
  // initialise before run
  G4LossTableManager* man = G4LossTableManager::Instance();

  // using spline for element selectors should be investigated in details
  // because small number of points may provide biased results
  // large number of points requires significant increase of memory
  //G4bool spline = man->SplineFlag();
  G4bool spline = false;

  //G4cout << "IES: for " << GetName() << " Emin(MeV)= " << lowLimit/MeV 
  //     << " Emax(MeV)= " << highLimit/MeV << G4endl;

  // two times less bins because probability functon is normalized 
  // so correspondingly is more smooth
  G4int nbins = G4int(man->GetNumberOfBinsPerDecade()
                      * std::log10(highLimit/lowLimit) / 6.0);
  if(nbins < 5) { nbins = 5; }

  G4ProductionCutsTable* theCoupleTable=
    G4ProductionCutsTable::GetProductionCutsTable();
  G4int numOfCouples = theCoupleTable->GetTableSize();

  // prepare vector
  if(numOfCouples > nSelectors) { 
    elmSelectors.resize(numOfCouples,0); 
    nSelectors = numOfCouples;
  }

  // initialise vector
  for(G4int i=0; i<numOfCouples; ++i) {
    fCurrentCouple = theCoupleTable->GetMaterialCutsCouple(i);
    const G4Material* material = fCurrentCouple->GetMaterial();
    G4int idx = fCurrentCouple->GetIndex();

    // selector already exist check if should be deleted
    G4bool create = true;
    if(elmSelectors[i]) {
      if(material == elmSelectors[i]->GetMaterial()) { create = false; }
      else { delete elmSelectors[i]; }
    }
    if(create) {
      elmSelectors[i] = new G4EmElementSelector(this,material,nbins,
                                                lowLimit,highLimit,spline);
    }
    elmSelectors[i]->Initialise(p, cuts[idx]);
    //elmSelectors[i]->Dump(p);
  } 
}

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G4double G4VEmModel::ComputeDEDXPerVolume(const G4Material*,
                                          const G4ParticleDefinition*,
                                          G4double,G4double)
{
  return 0.0;
}

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G4double G4VEmModel::CrossSectionPerVolume(const G4Material* material,
                                           const G4ParticleDefinition* p,
                                           G4double ekin,
                                           G4double emin,
                                           G4double emax)
{
  SetupForMaterial(p, material, ekin);
  G4double cross = 0.0;
  const G4ElementVector* theElementVector = material->GetElementVector();
  const G4double* theAtomNumDensityVector = material->GetVecNbOfAtomsPerVolume();
  G4int nelm = material->GetNumberOfElements(); 
  if(nelm > nsec) {
    xsec.resize(nelm);
    nsec = nelm;
  }
  for (G4int i=0; i<nelm; i++) {
    cross += theAtomNumDensityVector[i]*
      ComputeCrossSectionPerAtom(p,(*theElementVector)[i],ekin,emin,emax);
    xsec[i] = cross;
  }
  return cross;
}

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void G4VEmModel::StartTracking(G4Track*)
{}

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const G4Element* G4VEmModel::SelectRandomAtom(const G4Material* material,
                                              const G4ParticleDefinition* pd,
                                              G4double kinEnergy,
                                              G4double tcut,
                                              G4double tmax)
{
  const G4ElementVector* theElementVector = material->GetElementVector();
  G4int n = material->GetNumberOfElements() - 1;
  fCurrentElement = (*theElementVector)[n];
  if (n > 0) {
    G4double x = G4UniformRand()*
                 G4VEmModel::CrossSectionPerVolume(material,pd,kinEnergy,tcut,tmax);
    for(G4int i=0; i<n; ++i) {
      if (x <= xsec[i]) {
        fCurrentElement = (*theElementVector)[i];
        break;
      }
    }
  }
  return fCurrentElement;
}

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G4double G4VEmModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
                                                G4double, G4double, G4double,
                                                G4double, G4double)
{
  return 0.0;
}

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void G4VEmModel::DefineForRegion(const G4Region*) 
{}

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G4double G4VEmModel::ChargeSquareRatio(const G4Track& track)
{
  return GetChargeSquareRatio(track.GetParticleDefinition(), 
                              track.GetMaterial(), track.GetKineticEnergy());
}

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G4double G4VEmModel::GetChargeSquareRatio(const G4ParticleDefinition* p,
                                          const G4Material*, G4double)
{
  G4double q = p->GetPDGCharge()/CLHEP::eplus;
  return q*q;
}

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G4double G4VEmModel::GetParticleCharge(const G4ParticleDefinition* p,
                                       const G4Material*, G4double)
{
  return p->GetPDGCharge();
}

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void G4VEmModel::CorrectionsAlongStep(const G4MaterialCutsCouple*,
                                      const G4DynamicParticle*,
                                      G4double&,G4double&,G4double)
{}

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G4double G4VEmModel::Value(const G4MaterialCutsCouple* couple,
                           const G4ParticleDefinition* p, G4double e)
{
  fCurrentCouple = couple;
  return e*e*CrossSectionPerVolume(couple->GetMaterial(),p,e,0.0,DBL_MAX);
}

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G4double G4VEmModel::MinPrimaryEnergy(const G4Material*,
                                      const G4ParticleDefinition*)
{
  return 0.0;
}

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G4double G4VEmModel::MaxSecondaryEnergy(const G4ParticleDefinition*,
                                        G4double kineticEnergy)
{
  return kineticEnergy;
}

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void G4VEmModel::SetupForMaterial(const G4ParticleDefinition*,
                                  const G4Material*, G4double)
{}

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void 
G4VEmModel::SetParticleChange(G4VParticleChange* p, G4VEmFluctuationModel* f)
{
  if(p && pParticleChange != p) { pParticleChange = p; }
  flucModel = f;
}

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void G4VEmModel::SetCrossSectionTable(G4PhysicsTable* p)
{
  if(p != xSectionTable) {
    if(xSectionTable) { 
      xSectionTable->clearAndDestroy(); 
      delete xSectionTable;
    }
    xSectionTable = p;
  }
}

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