G4SeltzerBergerModel.cc

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// $Id$
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4SeltzerBergerModel
//
// Author:        Vladimir Ivanchenko use inheritance from Andreas Schaelicke
//                base class implementing ultra relativistic bremsstrahlung
//                model 
//
// Creation date: 04.10.2011
//
// Modifications:
//
// -------------------------------------------------------------------
//
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#include "G4SeltzerBergerModel.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4Gamma.hh"
#include "Randomize.hh"
#include "G4Material.hh"
#include "G4Element.hh"
#include "G4ElementVector.hh"
#include "G4ProductionCutsTable.hh"
#include "G4ParticleChangeForLoss.hh"
#include "G4LossTableManager.hh"
#include "G4ModifiedTsai.hh"
 
#include "G4Physics2DVector.hh"
 
#include "G4ios.hh"
#include <fstream>
#include <iomanip>
 
 
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using namespace std;
 
G4Physics2DVector* G4SeltzerBergerModel::dataSB[101] = {0};
G4double G4SeltzerBergerModel::ylimit[101] = {0.0};
G4double G4SeltzerBergerModel::expnumlim = -12.;
 
G4SeltzerBergerModel::G4SeltzerBergerModel(const G4ParticleDefinition* p,
                       const G4String& nam)
  : G4eBremsstrahlungRelModel(p,nam),useBicubicInterpolation(false)
{
  SetLowEnergyLimit(0.0);
  SetLPMFlag(false);
  nwarn = 0;
}
 
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G4SeltzerBergerModel::~G4SeltzerBergerModel()
{
  for(size_t i=0; i<101; ++i) { 
    if(dataSB[i]) {
      delete dataSB[i]; 
      dataSB[i] = 0;
    } 
  }
}
 
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void G4SeltzerBergerModel::Initialise(const G4ParticleDefinition* p,
                      const G4DataVector& cuts)
{
  // check environment variable
  // Build the complete string identifying the file with the data set
  char* path = getenv("G4LEDATA");
 
  // Access to elements
  const G4ElementTable* theElmTable = G4Element::GetElementTable();
  size_t numOfElm = G4Element::GetNumberOfElements();
  if(numOfElm > 0) {
    for(size_t i=0; i<numOfElm; ++i) {
      G4int Z = G4int(((*theElmTable)[i])->GetZ());
      if(Z < 1)        { Z = 1; }
      else if(Z > 100) { Z = 100; }
      //G4cout << "Z= " << Z << G4endl;
      // Initialisation
      if(!dataSB[Z]) { ReadData(Z, path); }
    }
  }
 
  G4eBremsstrahlungRelModel::Initialise(p, cuts);
}
 
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void G4SeltzerBergerModel::ReadData(size_t Z, const char* path)
{
  //  G4cout << "ReadData Z= " << Z << G4endl;
  // G4cout << "Status for Z= " << dataSB[Z] << G4endl;
  //if(path) { G4cout << path << G4endl; }
  if(dataSB[Z]) { return; }
  const char* datadir = path;
 
  if(!datadir) {
    datadir = getenv("G4LEDATA");
    if(!datadir) {
      G4Exception("G4SeltzerBergerModel::ReadData()","em0006",FatalException,
          "Environment variable G4LEDATA not defined");
      return;
    }
  }
  std::ostringstream ost;
  ost << datadir << "/brem_SB/br" << Z;
  std::ifstream fin(ost.str().c_str());
  if( !fin.is_open()) {
    G4ExceptionDescription ed;
    ed << "Bremsstrahlung data file <" << ost.str().c_str()
       << "> is not opened!" << G4endl;
    G4Exception("G4SeltzerBergerModel::ReadData()","em0003",FatalException,
        ed,"G4LEDATA version should be G4EMLOW6.23 or later.");
    return;
  } 
  //G4cout << "G4SeltzerBergerModel read from <" << ost.str().c_str() 
  //     << ">" << G4endl;
  G4Physics2DVector* v = new G4Physics2DVector();
  const G4double emaxlog = 4*log(10.);
  if(v->Retrieve(fin)) { 
    if(useBicubicInterpolation) { v->SetBicubicInterpolation(true); }
    dataSB[Z] = v; 
    ylimit[Z] = v->Value(0.97, emaxlog);
  } else {
    G4ExceptionDescription ed;
    ed << "Bremsstrahlung data file <" << ost.str().c_str()
       << "> is not retrieved!" << G4endl;
    G4Exception("G4SeltzerBergerModel::ReadData()","em0005",FatalException,
        ed,"G4LEDATA version should be G4EMLOW6.23 or later.");
    delete v;
  }
  // G4cout << dataSB[Z] << G4endl;
}
 
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G4double G4SeltzerBergerModel::ComputeDXSectionPerAtom(G4double gammaEnergy)
{
 
  if(gammaEnergy < 0.0 || kinEnergy <= 0.0) { return 0.0; }
  G4double x = gammaEnergy/kinEnergy;
  G4double y = log(kinEnergy/MeV);
  G4int Z = G4int(currentZ);
  //G4cout << "G4SeltzerBergerModel::ComputeDXSectionPerAtom Z= " << Z
  //     << " x= " << x << " y= " << y << " " << dataSB[Z] << G4endl;
  if(!dataSB[Z]) { ReadData(Z); }
  G4double invb2 = totalEnergy*totalEnergy/(kinEnergy*(kinEnergy + 2*particleMass));
  G4double cross = dataSB[Z]->Value(x,y)*invb2*millibarn/bremFactor;
  
  if(!isElectron) {
    G4double invbeta1 = sqrt(invb2);
    G4double e2 = kinEnergy - gammaEnergy;
    if(e2 > 0.0) {
      G4double invbeta2 = (e2 + particleMass)/sqrt(e2*(e2 + 2*particleMass));
      G4double xxx = twopi*fine_structure_const*currentZ*(invbeta1 - invbeta2);
      if(xxx < expnumlim) { cross = 0.0; }
      else { cross *= exp(xxx); }
    } else {
      cross = 0.0;
    }
  }
  
  return cross;
}
 
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void 
G4SeltzerBergerModel::SampleSecondaries(std::vector<G4DynamicParticle*>* vdp, 
                    const G4MaterialCutsCouple* couple,
                    const G4DynamicParticle* dp,
                    G4double cutEnergy,
                    G4double maxEnergy)
{
  G4double kineticEnergy = dp->GetKineticEnergy();
  G4double cut  = std::min(cutEnergy, kineticEnergy);
  G4double emax = std::min(maxEnergy, kineticEnergy);
  if(cut >= emax) { return; }
 
  SetupForMaterial(particle, couple->GetMaterial(), kineticEnergy);
 
  const G4Element* elm = 
    SelectRandomAtom(couple,particle,kineticEnergy,cut,emax);
  SetCurrentElement(elm->GetZ());
  G4int Z = G4int(currentZ);
 
  totalEnergy = kineticEnergy + particleMass;
  densityCorr = densityFactor*totalEnergy*totalEnergy;
  G4double totMomentum = sqrt(kineticEnergy*(totalEnergy + electron_mass_c2));
  /*
  G4cout << "G4SeltzerBergerModel::SampleSecondaries E(MeV)= " 
     << kineticEnergy/MeV
     << " Z= " << Z << " cut(MeV)= " << cut/MeV 
     << " emax(MeV)= " << emax/MeV << " corr= " << densityCorr << G4endl;
  */
  G4double xmin = log(cut*cut + densityCorr);
  G4double xmax = log(emax*emax  + densityCorr);
  G4double y = log(kineticEnergy/MeV);
 
  G4double gammaEnergy, v; 
 
  // majoranta
  G4double x0 = cut/kineticEnergy;
  G4double vmax = dataSB[Z]->Value(x0, y)*1.02;
  //  G4double invbeta1 = 0;
 
  const G4double epeaklimit= 300*MeV; 
  const G4double elowlimit = 10*keV; 
 
  // majoranta corrected for e-
  if(isElectron && x0 < 0.97 && 
     ((kineticEnergy > epeaklimit) || (kineticEnergy < elowlimit))) {
    G4double ylim = std::min(ylimit[Z],1.1*dataSB[Z]->Value(0.97, y)); 
    if(ylim > vmax) { vmax = ylim; }
  }
  if(x0 < 0.05) { vmax *= 1.2; }
 
  //G4cout<<"y= "<<y<<" xmin= "<<xmin<<" xmax= "<<xmax<<" vmax= "<<vmax<<G4endl;
  //  G4int ncount = 0;
  do {
    //++ncount;
    G4double x = exp(xmin + G4UniformRand()*(xmax - xmin)) - densityCorr;
    if(x < 0.0) { x = 0.0; }
    gammaEnergy = sqrt(x);
    G4double x1 = gammaEnergy/kineticEnergy;
    v = dataSB[Z]->Value(x1, y);
 
    // correction for positrons        
    if(!isElectron) {
      G4double e1 = kineticEnergy - cut;
      G4double invbeta1 = (e1 + particleMass)/sqrt(e1*(e1 + 2*particleMass));
      G4double e2 = kineticEnergy - gammaEnergy;
      G4double invbeta2 = (e2 + particleMass)/sqrt(e2*(e2 + 2*particleMass));
      G4double xxx = twopi*fine_structure_const*currentZ*(invbeta1 - invbeta2); 
 
      if(xxx < expnumlim) { v = 0.0; }
      else { v *= exp(xxx); }
    }
   
    if (v > 1.05*vmax && nwarn < 20) {
      ++nwarn;
      G4cout << "### G4SeltzerBergerModel Warning: Majoranta exceeded! "
         << v << " > " << vmax << " by " << v/vmax
         << " Egamma(MeV)= " << gammaEnergy
         << " Ee(MeV)= " << kineticEnergy
         << " Z= " << Z << "  " << particle->GetParticleName()
    //<< " ncount= " << ncount
         << G4endl;
     
      if ( 20 == nwarn ) {
    G4cout << "### G4SeltzerBergerModel Warnings will not be printed anymore"
           << G4endl;
      }
    }
  } while (v < vmax*G4UniformRand());
 
  //
  // angles of the emitted gamma. ( Z - axis along the parent particle)
  // use general interface
  //
 
  G4ThreeVector gammaDirection = 
    GetAngularDistribution()->SampleDirection(dp, totalEnergy-gammaEnergy,
                          Z, couple->GetMaterial());
 
  // create G4DynamicParticle object for the Gamma
  G4DynamicParticle* gamma = 
    new G4DynamicParticle(theGamma,gammaDirection,gammaEnergy);
  vdp->push_back(gamma);
  
  G4ThreeVector direction = (totMomentum*dp->GetMomentumDirection()
                 - gammaEnergy*gammaDirection).unit();
 
  /*
  G4cout << "### G4SBModel: v= "
     << " Eg(MeV)= " << gammaEnergy
     << " Ee(MeV)= " << kineticEnergy
     << " DirE " << direction << " DirG " << gammaDirection
     << G4endl;
  */
  // energy of primary
  G4double finalE = kineticEnergy - gammaEnergy;
 
  // stop tracking and create new secondary instead of primary
  if(gammaEnergy > SecondaryThreshold()) {
    fParticleChange->ProposeTrackStatus(fStopAndKill);
    fParticleChange->SetProposedKineticEnergy(0.0);
    G4DynamicParticle* el = 
      new G4DynamicParticle(const_cast<G4ParticleDefinition*>(particle),
                direction, finalE);
    vdp->push_back(el);
 
    // continue tracking
  } else {
    fParticleChange->SetProposedMomentumDirection(direction);
    fParticleChange->SetProposedKineticEnergy(finalE);
  }
}
 
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