source: trunk/source/processes/electromagnetic/lowenergy/src/G4PenelopeComptonModel.cc @ 1168

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//
// $Id: G4PenelopeComptonModel.cc,v 1.4 2009/04/18 18:29:34 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-03-beta-cand-01 $
//
// Author: Luciano Pandola
//
// History:
// --------
// 02 Oct 2008   L Pandola    Migration from process to model 
// 28 Oct 2008   L Pandola    Treat the database data from Penelope according to the 
//                            original model, namely merging levels below 15 eV in 
//                            a single one. Still, it is not fully compliant with the 
//                            original Penelope model, because plasma excitation is not 
//                            considered.
// 22 Nov 2008   L Pandola    Make unit of measurements explicit for binding energies 
//                            that are read from the external files.
// 24 Nov 2008   L Pandola    Find a cleaner way to delete vectors.
// 16 Apr 2009   V Ivanchenko Cleanup initialisation and generation of secondaries:
//                  - apply internal high-energy limit only in constructor 
//                  - do not apply low-energy limit (default is 0)
//                  - do not apply production threshold on level of the model
//

#include "G4PenelopeComptonModel.hh"
#include "G4ParticleDefinition.hh"
#include "G4MaterialCutsCouple.hh"
#include "G4ProductionCutsTable.hh"
#include "G4DynamicParticle.hh"
#include "G4VEMDataSet.hh"
#include "G4PhysicsTable.hh"
#include "G4ElementTable.hh"
#include "G4Element.hh"
#include "G4PhysicsLogVector.hh"
#include "G4PenelopeIntegrator.hh"
#include "G4AtomicTransitionManager.hh"
#include "G4AtomicDeexcitation.hh"
#include "G4AtomicShell.hh"
#include "G4Gamma.hh"
#include "G4Electron.hh"

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....


G4PenelopeComptonModel::G4PenelopeComptonModel(const G4ParticleDefinition*,
                                             const G4String& nam)
  :G4VEmModel(nam),ionizationEnergy(0),hartreeFunction(0),
   occupationNumber(0),isInitialised(false)
{
  fIntrinsicLowEnergyLimit = 100.0*eV;
  fIntrinsicHighEnergyLimit = 100.0*GeV;
  //  SetLowEnergyLimit(fIntrinsicLowEnergyLimit);
  SetHighEnergyLimit(fIntrinsicHighEnergyLimit);
  //
  energyForIntegration = 0.0;
  ZForIntegration = 1;

  fUseAtomicDeexcitation = true;
  verboseLevel= 0;
  // Verbosity scale:
  // 0 = nothing 
  // 1 = warning for energy non-conservation 
  // 2 = details of energy budget
  // 3 = calculation of cross sections, file openings, sampling of atoms
  // 4 = entering in methods

  //These vectors do not change when materials or cut change.
  //Therefore I can read it at the constructor
  ionizationEnergy = new std::map<G4int,G4DataVector*>;
  hartreeFunction  = new std::map<G4int,G4DataVector*>;
  occupationNumber = new std::map<G4int,G4DataVector*>;

  ReadData(); //Read data from file

}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4PenelopeComptonModel::~G4PenelopeComptonModel()
{  
  std::map <G4int,G4DataVector*>::iterator i;
  for (i=ionizationEnergy->begin();i != ionizationEnergy->end();i++)
    if (i->second) delete i->second;
  for (i=hartreeFunction->begin();i != hartreeFunction->end();i++)
    if (i->second) delete i->second;
  for (i=occupationNumber->begin();i != occupationNumber->end();i++)
    if (i->second) delete i->second;


  if (ionizationEnergy)
    delete ionizationEnergy;
  if (hartreeFunction)
    delete hartreeFunction;
  if (occupationNumber)
    delete occupationNumber;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

void G4PenelopeComptonModel::Initialise(const G4ParticleDefinition* particle,
                                        const G4DataVector& cuts)
{
  if (verboseLevel > 3)
    G4cout << "Calling G4PenelopeComptonModel::Initialise()" << G4endl;

  InitialiseElementSelectors(particle,cuts);

  if (verboseLevel > 0) {
    G4cout << "Penelope Compton model is initialized " << G4endl
           << "Energy range: "
           << LowEnergyLimit() / keV << " keV - "
           << HighEnergyLimit() / GeV << " GeV"
           << G4endl;
  }

  if(isInitialised) return;
  fParticleChange = GetParticleChangeForGamma();
  isInitialised = true; 
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4PenelopeComptonModel::ComputeCrossSectionPerAtom(
                                       const G4ParticleDefinition*,
                                             G4double energy,
                                             G4double Z, G4double,
                                             G4double, G4double)
{
  // Penelope model to calculate the Compton scattering cross section:
  // D. Brusa et al., Nucl. Instrum. Meth. A 379 (1996) 167
  // 
  // The cross section for Compton scattering is calculated according to the Klein-Nishina 
  // formula for energy > 5 MeV.
  // For E < 5 MeV it is used a parametrization for the differential cross-section dSigma/dOmega,
  // which is integrated numerically in cos(theta), G4PenelopeComptonModel::DifferentialCrossSection().
  // The parametrization includes the J(p) 
  // distribution profiles for the atomic shells, that are tabulated from Hartree-Fock calculations 
  // from F. Biggs et al., At. Data Nucl. Data Tables 16 (1975) 201
  //
  if (verboseLevel > 3)
    G4cout << "Calling ComputeCrossSectionPerAtom() of G4PenelopeComptonModel" << G4endl;

  G4int iZ = (G4int) Z;
  G4double cs=0.0;
  energyForIntegration=energy; 
  ZForIntegration = iZ;
  if (energy< 5*MeV)
    {
      // numerically integrate differential cross section dSigma/dOmega
      G4PenelopeIntegrator<G4PenelopeComptonModel,G4double (G4PenelopeComptonModel::*)(G4double)> 
        theIntegrator;
      cs = theIntegrator.Calculate(this,&G4PenelopeComptonModel::DifferentialCrossSection,-1.0,1.0,1e-05);
    }
  else 
    {
      // use Klein-Nishina formula
      G4double ki=energy/electron_mass_c2;
      G4double ki3=ki*ki;
      G4double ki2=1.0+2*ki;
      G4double ki1=ki3-ki2-1.0;
      G4double t0=1.0/(ki2);
      G4double csl = 0.5*ki3*t0*t0+ki2*t0+ki1*std::log(t0)-(1.0/t0);
      G4int nosc = occupationNumber->find(iZ)->second->size();
      for (G4int i=0;i<nosc;i++)
        {
          G4double ionEnergy = (*(ionizationEnergy->find(iZ)->second))[i];
          G4double tau=(energy-ionEnergy)/energy;
          if (tau > t0)
            {
              G4double csu = 0.5*ki3*tau*tau+ki2*tau+ki1*std::log(tau)-(1.0/tau);
              G4int f = (G4int) (*(occupationNumber->find(iZ)->second))[i];
              cs = cs + f*(csu-csl);
            }
        }
      cs=pi*classic_electr_radius*classic_electr_radius*cs/(ki*ki3);
    }
  
  if (verboseLevel > 2)
    G4cout << "Compton cross Section at " << energy/keV << " keV for Z=" << Z << 
      " = " << cs/barn << " barn" << G4endl;
  return cs;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

void G4PenelopeComptonModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
                                              const G4MaterialCutsCouple* couple,
                                              const G4DynamicParticle* aDynamicGamma,
                                              G4double,
                                              G4double)
{
  
  // Penelope model to sample the Compton scattering final state.
  // D. Brusa et al., Nucl. Instrum. Meth. A 379 (1996) 167
  // The model determines also the original shell from which the electron is expelled, 
  // in order to produce fluorescence de-excitation (from G4DeexcitationManager)
  // 
  // The final state for Compton scattering is calculated according to the Klein-Nishina 
  // formula for energy > 5 MeV. In this case, the Doppler broadening is negligible and 
  // one can assume that the target electron is at rest.
  // For E < 5 MeV it is used the parametrization for the differential cross-section dSigma/dOmega,
  // to sample the scattering angle and the energy of the emerging electron, which is  
  // G4PenelopeComptonModel::DifferentialCrossSection(). The rejection method is 
  // used to sample cos(theta). The efficiency increases monotonically with photon energy and is 
  // nearly independent on the Z; typical values are 35%, 80% and 95% for 1 keV, 1 MeV and 10 MeV, 
  // respectively.
  // The parametrization includes the J(p) distribution profiles for the atomic shells, that are 
  // tabulated 
  // from Hartree-Fock calculations from F. Biggs et al., At. Data Nucl. Data Tables 16 (1975) 201. 
  // Doppler broadening is included.
  //

  if (verboseLevel > 3)
    G4cout << "Calling SampleSecondaries() of G4PenelopeComptonModel" << G4endl;

  G4double photonEnergy0 = aDynamicGamma->GetKineticEnergy();

  if (photonEnergy0 <= fIntrinsicLowEnergyLimit)
    {
      fParticleChange->ProposeTrackStatus(fStopAndKill);
      fParticleChange->SetProposedKineticEnergy(0.);
      fParticleChange->ProposeLocalEnergyDeposit(photonEnergy0);
      return ;
    }

  G4ParticleMomentum photonDirection0 = aDynamicGamma->GetMomentumDirection();

  // Select randomly one element in the current material
  if (verboseLevel > 2)
    G4cout << "Going to select element in " << couple->GetMaterial()->GetName() << G4endl;
  // atom can be selected effitiantly if element selectors are initialised 
  const G4Element* anElement = 
    SelectRandomAtom(couple,G4Gamma::GammaDefinition(),photonEnergy0);
  G4int Z = (G4int) anElement->GetZ();
  if (verboseLevel > 2)
    G4cout << "Selected " << anElement->GetName() << G4endl;

  const G4int nmax = 64;
  G4double rn[nmax],pac[nmax];
  
  G4double ki,ki1,ki2,ki3,taumin,a1,a2;
  G4double tau,TST;
  G4double S=0.0;
  G4double epsilon,cosTheta;
  G4double harFunc = 0.0;
  G4int occupNb= 0;
  G4double ionEnergy=0.0;
  G4int nosc = occupationNumber->find(Z)->second->size();
  G4int iosc = nosc;
  ki = photonEnergy0/electron_mass_c2;
  ki2 = 2*ki+1.0;
  ki3 = ki*ki;
  ki1 = ki3-ki2-1.0;
  taumin = 1.0/ki2;
  a1 = std::log(ki2);
  a2 = a1+2.0*ki*(1.0+ki)/(ki2*ki2);
  //If the incoming photon is above 5 MeV, the quicker approach based on the 
  //pure Klein-Nishina formula is used
  if (photonEnergy0 > 5*MeV)
    {
      do{
        do{
          if ((a2*G4UniformRand()) < a1)
            {
              tau = std::pow(taumin,G4UniformRand());
            }
          else
            {
              tau = std::sqrt(1.0+G4UniformRand()*(taumin*taumin-1.0));
            }
          //rejection function
          TST = (1+tau*(ki1+tau*(ki2+tau*ki3)))/(ki3*tau*(1.0+tau*tau));
        }while (G4UniformRand()> TST);
        epsilon=tau;
        cosTheta = 1.0 - (1.0-tau)/(ki*tau);
        //Target shell electrons
        TST = Z*G4UniformRand();
        iosc = nosc;
        S=0.0;
        for (G4int j=0;j<nosc;j++)
          {
            occupNb = (G4int) (*(occupationNumber->find(Z)->second))[j];
            S = S + occupNb;
            if (S > TST) iosc = j;
            if (S > TST) break; 
          }
        ionEnergy = (*(ionizationEnergy->find(Z)->second))[iosc];
      }while((epsilon*photonEnergy0-photonEnergy0+ionEnergy) >0);
    }
  else //photonEnergy0 < 5 MeV
    {
      //Incoherent scattering function for theta=PI
      G4double s0=0.0;
      G4double pzomc=0.0,rni=0.0;
      G4double aux=0.0;
      for (G4int i=0;i<nosc;i++){
        ionEnergy = (*(ionizationEnergy->find(Z)->second))[i];
        if (photonEnergy0 > ionEnergy)
          {
            G4double aux = photonEnergy0*(photonEnergy0-ionEnergy)*2.0;
            harFunc = (*(hartreeFunction->find(Z)->second))[i]/fine_structure_const;
            occupNb = (G4int) (*(occupationNumber->find(Z)->second))[i];
            pzomc = harFunc*(aux-electron_mass_c2*ionEnergy)/
               (electron_mass_c2*std::sqrt(2.0*aux+ionEnergy*ionEnergy));
            if (pzomc > 0) 
              {
                rni = 1.0-0.5*std::exp(0.5-(std::sqrt(0.5)+std::sqrt(2.0)*pzomc)*
                                       (std::sqrt(0.5)+std::sqrt(2.0)*pzomc));
              }
            else
              {
                rni = 0.5*std::exp(0.5-(std::sqrt(0.5)-std::sqrt(2.0)*pzomc)*
                                   (std::sqrt(0.5)-std::sqrt(2.0)*pzomc));
              }
            s0 = s0 + occupNb*rni;
          }
      }
      
      //Sampling tau
      G4double cdt1;
      do
        {
          if ((G4UniformRand()*a2) < a1)
            {
              tau = std::pow(taumin,G4UniformRand());
            }
          else
            {
              tau = std::sqrt(1.0+G4UniformRand()*(taumin*taumin-1.0));
            }
          cdt1 = (1.0-tau)/(ki*tau);
          S=0.0;
          //Incoherent scattering function
          for (G4int i=0;i<nosc;i++){
            ionEnergy = (*(ionizationEnergy->find(Z)->second))[i];
            if (photonEnergy0 > ionEnergy) //sum only on excitable levels
              {
                aux = photonEnergy0*(photonEnergy0-ionEnergy)*cdt1;
                harFunc = (*(hartreeFunction->find(Z)->second))[i]/fine_structure_const;
                occupNb = (G4int) (*(occupationNumber->find(Z)->second))[i];
                pzomc = harFunc*(aux-electron_mass_c2*ionEnergy)/
                  (electron_mass_c2*std::sqrt(2.0*aux+ionEnergy*ionEnergy));
                if (pzomc > 0) 
                  {
                    rn[i] = 1.0-0.5*std::exp(0.5-(std::sqrt(0.5)+std::sqrt(2.0)*pzomc)*
                                             (std::sqrt(0.5)+std::sqrt(2.0)*pzomc));
                  }
                else
                  {
                    rn[i] = 0.5*std::exp(0.5-(std::sqrt(0.5)-std::sqrt(2.0)*pzomc)*
                                         (std::sqrt(0.5)-std::sqrt(2.0)*pzomc));
                  }
                S = S + occupNb*rn[i];
                pac[i] = S;
              }
            else
              {
                pac[i] = S-(1e-06);
              }
          }
          //Rejection function
          TST = S*(1.0+tau*(ki1+tau*(ki2+tau*ki3)))/(ki3*tau*(1.0+tau*tau));  
        }while ((G4UniformRand()*s0) > TST);
      //Target electron shell
      cosTheta = 1.0 - cdt1;
      G4double fpzmax=0.0,fpz=0.0;
      G4double A=0.0;
      do
        {
          do
            {
              TST =S*G4UniformRand();
              iosc=nosc;
              for (G4int i=0;i<nosc;i++){
                if (pac[i]>TST) iosc = i;
                if (pac[i]>TST) break; 
              }
              A = G4UniformRand()*rn[iosc];
              harFunc = (*(hartreeFunction->find(Z)->second))[iosc]/fine_structure_const;
              occupNb = (G4int) (*(occupationNumber->find(Z)->second))[iosc];
              if (A < 0.5) {
                pzomc = (std::sqrt(0.5)-std::sqrt(0.5-std::log(2.0*A)))/
                  (std::sqrt(2.0)*harFunc);
              }
              else
                {
                  pzomc = (std::sqrt(0.5-std::log(2.0-2.0*A))-std::sqrt(0.5))/
                    (std::sqrt(2.0)*harFunc);
                }
            } while (pzomc < -1);
          // F(EP) rejection
          G4double XQC = 1.0+tau*(tau-2.0*cosTheta);
          G4double AF = std::sqrt(XQC)*(1.0+tau*(tau-cosTheta)/XQC);
          if (AF > 0) {
            fpzmax = 1.0+AF*0.2;
          }
          else
            {
              fpzmax = 1.0-AF*0.2;
            }
          fpz = 1.0+AF*std::max(std::min(pzomc,0.2),-0.2);
        }while ((fpzmax*G4UniformRand())>fpz);
  
      //Energy of the scattered photon
      G4double T = pzomc*pzomc;
      G4double b1 = 1.0-T*tau*tau;
      G4double b2 = 1.0-T*tau*cosTheta;
      if (pzomc > 0.0)
        {
          epsilon = (tau/b1)*(b2+std::sqrt(std::abs(b2*b2-b1*(1.0-T))));
        }
      else
        {
          epsilon = (tau/b1)*(b2-std::sqrt(std::abs(b2*b2-b1*(1.0-T))));
        }
    }
  

  //Ok, the kinematics has been calculated.
  G4double sinTheta = std::sqrt(1-cosTheta*cosTheta);
  G4double phi = twopi * G4UniformRand() ;
  G4double dirx = sinTheta * std::cos(phi);
  G4double diry = sinTheta * std::sin(phi);
  G4double dirz = cosTheta ;

  // Update G4VParticleChange for the scattered photon
  G4ThreeVector photonDirection1(dirx,diry,dirz);
  photonDirection1.rotateUz(photonDirection0);
  fParticleChange->ProposeMomentumDirection(photonDirection1) ;
  G4double photonEnergy1 = epsilon * photonEnergy0;

  if (photonEnergy1 > 0.)
  {
    fParticleChange->SetProposedKineticEnergy(photonEnergy1) ;
  }
  else
  {
    fParticleChange->SetProposedKineticEnergy(0.) ;
    fParticleChange->ProposeTrackStatus(fStopAndKill);
  }
  
  //Create scattered electron
  G4double diffEnergy = photonEnergy0*(1-epsilon);
  ionEnergy = (*(ionizationEnergy->find(Z)->second))[iosc];
  G4double Q2 = 
    photonEnergy0*photonEnergy0+photonEnergy1*(photonEnergy1-2.0*photonEnergy0*cosTheta);
  G4double cosThetaE; //scattering angle for the electron
  if (Q2 > 1.0e-12)
    {
      cosThetaE = (photonEnergy0-photonEnergy1*cosTheta)/std::sqrt(Q2);
    }
  else
    {
      cosThetaE = 1.0;
    }
  G4double sinThetaE = std::sqrt(1-cosThetaE*cosThetaE);

  //initialize here, then check photons created by Atomic-Deexcitation, and the final state e-
  std::vector<G4DynamicParticle*>* photonVector=0;

  const G4AtomicTransitionManager* transitionManager = G4AtomicTransitionManager::Instance();
  const G4AtomicShell* shell = transitionManager->Shell(Z,iosc);
  G4double bindingEnergy = shell->BindingEnergy();
  G4int shellId = shell->ShellId();
  G4double ionEnergyInPenelopeDatabase = ionEnergy;
  //protection against energy non-conservation
  ionEnergy = std::max(bindingEnergy,ionEnergyInPenelopeDatabase);  

  //subtract the excitation energy. If not emitted by fluorescence
  //the ionization energy is deposited as local energy deposition
  G4double eKineticEnergy = diffEnergy - ionEnergy; 
  G4double localEnergyDeposit = ionEnergy; 
  G4double energyInFluorescence = 0.; //testing purposes only

  if (eKineticEnergy < 0) 
    {
      //It means that there was some problem/mismatch between the two databases. 
      //Try to make it work
      //In this case available Energy (diffEnergy) < ionEnergy
      //Full residual energy is deposited locally
      localEnergyDeposit = diffEnergy;
      eKineticEnergy = 0.0;
    }
     
  //the local energy deposit is what remains: part of this may be spent for fluorescence.
  if(DeexcitationFlag() && Z > 5) {

    const G4ProductionCutsTable* theCoupleTable=
      G4ProductionCutsTable::GetProductionCutsTable();

    size_t index = couple->GetIndex();
    G4double cutg = (*(theCoupleTable->GetEnergyCutsVector(0)))[index];
    G4double cute = (*(theCoupleTable->GetEnergyCutsVector(1)))[index];

    // Generation of fluorescence
    // Data in EADL are available only for Z > 5
    // Protection to avoid generating photons in the unphysical case of
    // shell binding energy > photon energy
    if (localEnergyDeposit > cutg || localEnergyDeposit > cute)
      { 
        G4DynamicParticle* aPhoton;
        G4AtomicDeexcitation deexcitationManager;
        deexcitationManager.SetCutForSecondaryPhotons(cutg);
        deexcitationManager.SetCutForAugerElectrons(cute);
        deexcitationManager.ActivateAugerElectronProduction(false);
      
        photonVector = deexcitationManager.GenerateParticles(Z,shellId);
        if(photonVector) 
          {
            size_t nPhotons = photonVector->size();
            for (size_t k=0; k<nPhotons; k++)
              {
                aPhoton = (*photonVector)[k];
                if (aPhoton)
                  {
                    G4double itsEnergy = aPhoton->GetKineticEnergy();
                    if (itsEnergy <= localEnergyDeposit)
                      {
                        localEnergyDeposit -= itsEnergy;
                        if (aPhoton->GetDefinition() == G4Gamma::Gamma()) 
                          energyInFluorescence += itsEnergy;;
                        fvect->push_back(aPhoton);                  
                      }
                    else
                      {
                        delete aPhoton;
                        (*photonVector)[k]=0;
                      }
                  }
              }
            delete photonVector;
          }
      }
  }

  //Produce explicitely the electron only if its proposed kinetic energy is 
  //above the cut, otherwise add local energy deposition
  G4DynamicParticle* electron = 0;
  //  if (eKineticEnergy > cutE) // VI: may be consistency problem if cut is applied here
  if (eKineticEnergy > 0.0)
    {
      G4double xEl = sinThetaE * std::cos(phi+pi); 
      G4double yEl = sinThetaE * std::sin(phi+pi);
      G4double zEl = cosThetaE;
      G4ThreeVector eDirection(xEl,yEl,zEl); //electron direction
      eDirection.rotateUz(photonDirection0);
      electron = new G4DynamicParticle (G4Electron::Electron(),
                                        eDirection,eKineticEnergy) ;
      fvect->push_back(electron);
    }
  else
    {
      localEnergyDeposit += eKineticEnergy;
    }

  if (localEnergyDeposit < 0)
    {
      G4cout << "WARNING-" 
             << "G4PenelopeComptonModel::SampleSecondaries - Negative energy deposit"
             << G4endl;
      localEnergyDeposit=0.;
    }
  fParticleChange->ProposeLocalEnergyDeposit(localEnergyDeposit);
  
  G4double electronEnergy = 0.;
  if (verboseLevel > 1)
    {
      G4cout << "-----------------------------------------------------------" << G4endl;
      G4cout << "Energy balance from G4PenelopeCompton" << G4endl;
      G4cout << "Incoming photon energy: " << photonEnergy0/keV << " keV" << G4endl;
      G4cout << "-----------------------------------------------------------" << G4endl;
      G4cout << "Scattered photon: " << photonEnergy1/keV << " keV" << G4endl;
      if (electron)
        electronEnergy = eKineticEnergy;
      G4cout << "Scattered electron " << electronEnergy/keV << " keV" << G4endl;
      G4cout << "Fluorescence: " << energyInFluorescence/keV << " keV" << G4endl;
      G4cout << "Local energy deposit " << localEnergyDeposit/keV << " keV" << G4endl;
      G4cout << "Total final state: " << (photonEnergy1+electronEnergy+energyInFluorescence+
                                          localEnergyDeposit)/keV << 
        " keV" << G4endl;
      G4cout << "-----------------------------------------------------------" << G4endl;
    }
  if (verboseLevel > 0)
    {
      G4double energyDiff = std::fabs(photonEnergy1+
                                      electronEnergy+energyInFluorescence+
                                      localEnergyDeposit-photonEnergy0);
      if (energyDiff > 0.05*keV)
        G4cout << "Warning from G4PenelopeCompton: problem with energy conservation: " << 
          (photonEnergy1+electronEnergy+energyInFluorescence+localEnergyDeposit)/keV << 
          " keV (final) vs. " << 
          photonEnergy0/keV << " keV (initial)" << G4endl;
    }
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

void G4PenelopeComptonModel::ReadData()
{
  char* path = getenv("G4LEDATA");
  if (!path)
    {
      G4String excep = "G4PenelopeComptonModel - G4LEDATA environment variable not set!";
      G4Exception(excep);
    }
  G4String pathString(path);
  G4String pathFile = pathString + "/penelope/compton-pen.dat";
  std::ifstream file(pathFile);
  
  if (!file.is_open())
    {
      G4String excep = "G4PenelopeComptonModel - data file " + pathFile + " not found!";
      G4Exception(excep);
    }

  G4int k1,test,test1;
  G4double a1,a2;
  G4int Z=1,nLevels=0;

  if (!ionizationEnergy || !hartreeFunction || !occupationNumber)
    {
      G4String excep = "G4PenelopeComptonModel: problem with reading data from file";
      G4Exception(excep);
    }

  do{
    G4double harOfElectronsBelowThreshold = 0;
    G4int nbOfElectronsBelowThreshold = 0;
    G4DataVector* occVector = new G4DataVector;
    G4DataVector* harVector = new G4DataVector;
    G4DataVector* bindingEVector = new G4DataVector;
    file >> Z >> nLevels;
    for (G4int h=0;h<nLevels;h++)
      {
        file >> k1 >> a1 >> a2;
        //Make explicit unit of measurements for ionisation energy, which is MeV
        a1 *= MeV; 
        if (a1 > 15*eV)
          {
            occVector->push_back((G4double) k1);
            bindingEVector->push_back(a1);
            harVector->push_back(a2);
          }
        else
          {
            nbOfElectronsBelowThreshold += k1;
            harOfElectronsBelowThreshold += k1*a2;
          }
      }
    //Add the "final" level
    if (nbOfElectronsBelowThreshold)
      {
        occVector->push_back(nbOfElectronsBelowThreshold);
        bindingEVector->push_back(0*eV);
        G4double averageHartree = 
          harOfElectronsBelowThreshold/((G4double) nbOfElectronsBelowThreshold);
        harVector->push_back(averageHartree);
      }
    //Ok, done for element Z
    occupationNumber->insert(std::make_pair(Z,occVector));
    ionizationEnergy->insert(std::make_pair(Z,bindingEVector));
    hartreeFunction->insert(std::make_pair(Z,harVector));
    file >> test >> test1; //-1 -1 close the data for each Z
    if (test > 0) {
      G4String excep = "G4PenelopeComptonModel - data file corrupted!";
      G4Exception(excep);
    }
  }while (test != -2); //the very last Z is closed with -2 instead of -1
  file.close();
  if (verboseLevel > 2)
    {
      G4cout << "Data from G4PenelopeComptonModel read " << G4endl;
    }
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

G4double G4PenelopeComptonModel::DifferentialCrossSection(G4double cosTheta)
{
  //
  // Penelope model for the Compton scattering differential cross section 
  // dSigma/dOmega.
  // D. Brusa et al., Nucl. Instrum. Meth. A 379 (1996) 167
  // The parametrization includes the J(p) distribution profiles for the atomic shells, 
  // that are tabulated from Hartree-Fock calculations 
  // from F. Biggs et al., At. Data Nucl. Data Tables 16 (1975) 201
  //
  const G4double k2 = std::sqrt(2.0);
  const G4double k1 = std::sqrt(0.5);
  const G4double k12 = 0.5;
  G4double cdt1 = 1.0-cosTheta;
  G4double energy = energyForIntegration;
  G4int Z = ZForIntegration;
  //energy of Compton line;
  G4double EOEC = 1.0+(energy/electron_mass_c2)*cdt1; 
  G4double ECOE = 1.0/EOEC;
  //Incoherent scattering function (analytical profile)
  G4double sia = 0.0;
  G4int nosc = occupationNumber->find(Z)->second->size();
  for (G4int i=0;i<nosc;i++){
    G4double ionEnergy = (*(ionizationEnergy->find(Z)->second))[i];
    //Sum only of those shells for which E>Eion
    if (energy > ionEnergy)
      {
        G4double aux = energy * (energy-ionEnergy)*cdt1;
        G4double Pzimax = 
          (aux - electron_mass_c2*ionEnergy)/(electron_mass_c2*std::sqrt(2*aux+ionEnergy*ionEnergy));
        G4double harFunc = (*(hartreeFunction->find(Z)->second))[i]/fine_structure_const;
        G4int occupNb = (G4int) (*(occupationNumber->find(Z)->second))[i];
        G4double x = harFunc*Pzimax;
        G4double siap = 0;
        if (x > 0) 
          {
            siap = 1.0-0.5*std::exp(k12-(k1+k2*x)*(k1+k2*x));
          }
        else
          {
            siap = 0.5*std::exp(k12-(k1-k2*x)*(k1-k2*x));
          }
        sia = sia + occupNb*siap; //sum of all contributions;
      }
  }
  G4double XKN = EOEC+ECOE-1+cosTheta*cosTheta;
  G4double diffCS = pi*classic_electr_radius*classic_electr_radius*ECOE*ECOE*XKN*sia;
  return diffCS;
}