G4SeltzerBergerModel.cc

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// $Id: G4SeltzerBergerModel.cc 98737 2016-08-09 12:51:38Z gcosmo $
//
// -------------------------------------------------------------------
//
// 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 "G4ModifiedTsai.hh"

#include "G4Physics2DVector.hh"
#include "G4Exp.hh"
#include "G4Log.hh"

#include "G4ios.hh"
#include <fstream>
#include <iomanip>

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using namespace std;

G4Physics2DVector* G4SeltzerBergerModel::dataSB[] = {nullptr};
G4double G4SeltzerBergerModel::ylimit[] = {0.0};
G4double G4SeltzerBergerModel::expnumlim = -12.;

G4SeltzerBergerModel::G4SeltzerBergerModel(const G4ParticleDefinition* p,
                                           const G4String& nam)
  : G4eBremsstrahlungRelModel(p,nam),useBicubicInterpolation(false)
{
  SetLowestKinEnergy(1.0*keV);
  SetLowEnergyLimit(LowestKinEnergy());
  SetLPMFlag(false);
  nwarn = 0;
  idx = idy = 0;
}

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G4SeltzerBergerModel::~G4SeltzerBergerModel()
{
  if(IsMaster()) {
    for(size_t i=0; i<101; ++i) { 
      if(dataSB[i]) {
        delete dataSB[i]; 
        dataSB[i] = nullptr;
      } 
    }
  }
}

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void G4SeltzerBergerModel::Initialise(const G4ParticleDefinition* p,
                                      const G4DataVector& cuts)
{
  // Access to elements
  if(IsMaster()) {

    // check environment variable
    // Build the complete string identifying the file with the data set
    char* path = getenv("G4LEDATA");

    const G4ElementTable* theElmTable = G4Element::GetElementTable();
    size_t numOfElm = G4Element::GetNumberOfElements();
    if(numOfElm > 0) {
      for(size_t i=0; i<numOfElm; ++i) {
        G4int Z = G4lrint(((*theElmTable)[i])->GetZ());
        if(Z < 1)        { Z = 1; }
        else if(Z > 100) { Z = 100; }
        //G4cout << "Z= " << Z << G4endl;
        // Initialisation
        if(nullptr == dataSB[Z]) { ReadData(Z, path); }
      }
    }
  }

  G4eBremsstrahlungRelModel::Initialise(p, cuts);
}

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G4String G4SeltzerBergerModel::DirectoryPath() const
{
  return "/brem_SB/br";
}

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void G4SeltzerBergerModel::ReadData(G4int 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 << DirectoryPath() << 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!";
    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();
  if(v->Retrieve(fin)) { 
    if(useBicubicInterpolation) { v->SetBicubicInterpolation(true); }
    dataSB[Z] = v; 
    static const G4double emaxlog = 4*G4Log(10.);
    ylimit[Z] = v->Value(0.97, emaxlog, idx, idy);
  } else {
    G4ExceptionDescription ed;
    ed << "Bremsstrahlung data file <" << ost.str().c_str()
       << "> is not retrieved!";
    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 = G4Log(kinEnergy/MeV);
  G4int Z = G4lrint(currentZ);

  //G4cout << "G4SeltzerBergerModel::ComputeDXSectionPerAtom Z= " << Z
  //         << " x= " << x << " y= " << y << " " << dataSB[Z] << G4endl;
  if(nullptr == dataSB[Z]) { InitialiseForElement(0, Z); }
  /*
    G4ExceptionDescription ed;
    ed << "Bremsstrahlung data for Z= " << Z
       << " are not initialized!";
    G4Exception("G4SeltzerBergerModel::ComputeDXSectionPerAtom()","em0005",
                FatalException, ed,
                "G4LEDATA version should be G4EMLOW6.23 or later.");
  }
  */
  G4double invb2 = 
    totalEnergy*totalEnergy/(kinEnergy*(kinEnergy + 2*particleMass));
  G4double cross = dataSB[Z]->Value(x,y,idx,idy)*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));
      static const G4double alpha = CLHEP::twopi*CLHEP::fine_structure_const; 
      G4double xxx = alpha*currentZ*(invbeta1 - invbeta2);
      if(xxx < expnumlim) { cross = 0.0; }
      else { cross *= G4Exp(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->GetZasInt());

  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 = G4Log(cut*cut + densityCorr);
  G4double xmax = G4Log(emax*emax  + densityCorr);
  G4double y = G4Log(kineticEnergy/MeV);

  G4double gammaEnergy, v; 

  // majoranta
  G4double x0 = cut/kineticEnergy;
  G4double vmax;
  if(currentZ <= 92) {
    vmax = dataSB[currentZ]->Value(x0, y, idx, idy)*1.02;
  } else {
    idx = idy = 0;
    vmax = dataSB[currentZ]->Value(x0, y, idx, idy)*1.2;
  }

  static const G4double epeaklimit= 300*CLHEP::MeV; 
  static const G4double elowlimit = 20*CLHEP::keV; 

  // majoranta corrected for e-
  if(isElectron && x0 < 0.97 && 
     ((kineticEnergy > epeaklimit) || (kineticEnergy < elowlimit))) {
    G4double ylim = std::min(ylimit[currentZ],1.1*dataSB[currentZ]->Value(0.97,y,idx,idy));
    if(ylim > vmax) { vmax = ylim; }
  }
  if(x0 < 0.05) { vmax *= 1.2; }

  //G4cout<<"y= "<<y<<" xmin= "<<xmin<<" xmax= "<<xmax
  //<<" vmax= "<<vmax<<G4endl;
  static const G4int ncountmax = 100;
  CLHEP::HepRandomEngine* rndmEngine = G4Random::getTheEngine();
  G4double rndm[2];

  for(G4int nn=0; nn<ncountmax; ++nn) {
    rndmEngine->flatArray(2, rndm);
    G4double x = G4Exp(xmin + rndm[0]*(xmax - xmin)) - densityCorr;
    if(x < 0.0) { x = 0.0; }
    gammaEnergy = sqrt(x);
    G4double x1 = gammaEnergy/kineticEnergy;
    v = dataSB[currentZ]->Value(x1, y, idx, idy);

    // 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 *= G4Exp(xxx); }
    }
   
    if (v > 1.05*vmax && nwarn < 5) {
      ++nwarn;
      G4ExceptionDescription ed;
      ed << "### G4SeltzerBergerModel Warning: Majoranta exceeded! "
         << v << " > " << vmax << " by " << v/vmax
         << " Niter= " << nn 
         << " Egamma(MeV)= " << gammaEnergy
         << " Ee(MeV)= " << kineticEnergy
         << " Z= " << currentZ << "  " << particle->GetParticleName();
     
      if ( 20 == nwarn ) {
        ed << "\n ### G4SeltzerBergerModel Warnings stopped";
      }
      G4Exception("G4SeltzerBergerModel::SampleScattering","em0044",
                  JustWarning, ed,"");

    }
    if(v >= vmax*rndm[1]) { break; }
  }

  //
  // angles of the emitted gamma. ( Z - axis along the parent particle)
  // use general interface
  //

  G4ThreeVector gammaDirection = 
    GetAngularDistribution()->SampleDirection(dp, totalEnergy-gammaEnergy,
                                              currentZ, 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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#include "G4AutoLock.hh"
namespace { G4Mutex SeltzerBergerModelMutex = G4MUTEX_INITIALIZER; }
void G4SeltzerBergerModel::InitialiseForElement(const G4ParticleDefinition*, 
                                                G4int Z)
{
  G4AutoLock l(&SeltzerBergerModelMutex);
  // G4cout << "G4SeltzerBergerModel::InitialiseForElement Z= " << Z << G4endl;
  if(nullptr == dataSB[Z]) { ReadData(Z); }
}

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