G4LindhardSorensenIonModel.cc

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// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4LindhardSorensenIonModel
//
// Author:        Alexander Bagulya & Vladimir Ivanchenko
//
// Creation date: 16.04.2018
//
//
// -------------------------------------------------------------------
//
 
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#include "G4LindhardSorensenIonModel.hh"
#include "Randomize.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4Electron.hh"
#include "G4LossTableManager.hh"
#include "G4EmCorrections.hh"
#include "G4ParticleChangeForLoss.hh"
#include "G4Log.hh"
#include "G4DeltaAngle.hh"
#include "G4LindhardSorensenData.hh"
#include "G4BraggModel.hh"
#include "G4BetheBlochModel.hh"
#include "G4IonICRU73Data.hh"
#include "G4AutoLock.hh"
 
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using namespace std;
 
G4LindhardSorensenData* G4LindhardSorensenIonModel::lsdata = nullptr;
G4IonICRU73Data* G4LindhardSorensenIonModel::fIonData = nullptr;
 
namespace
{
  G4Mutex ionXSMutex = G4MUTEX_INITIALIZER;
}
 
G4LindhardSorensenIonModel::G4LindhardSorensenIonModel(const G4ParticleDefinition*, 
                                                       const G4String& nam)
  : G4VEmModel(nam),
    twoln10(2.0*G4Log(10.0))
{
  theElectron = G4Electron::Electron();
  corr = G4LossTableManager::Instance()->EmCorrections();  
  nist = G4NistManager::Instance();
  fBraggModel = new G4BraggModel();
  fBBModel = new G4BetheBlochModel();
  fElimit = 2.0*CLHEP::MeV;
}
 
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G4LindhardSorensenIonModel::~G4LindhardSorensenIonModel() {
  if(isFirst) {
    delete lsdata;
    delete fIonData;
    lsdata = nullptr;
    fIonData = nullptr;
  }
}
 
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void G4LindhardSorensenIonModel::Initialise(const G4ParticleDefinition* p,
                                            const G4DataVector& ptr)
{
  fBraggModel->Initialise(p, ptr);
  fBBModel->Initialise(p, ptr);
  SetParticle(p);
 
  // always false before the run
  SetDeexcitationFlag(false);
 
  if(nullptr == fParticleChange) {
    fParticleChange = GetParticleChangeForLoss();
    if(UseAngularGeneratorFlag() && nullptr == GetAngularDistribution()) {
      SetAngularDistribution(new G4DeltaAngle());
    }
  }
  if(nullptr == lsdata) { 
    G4AutoLock l(&ionXSMutex);
    if(nullptr == lsdata) { 
      isFirst = true;
      lsdata = new G4LindhardSorensenData();
      fIonData = new G4IonICRU73Data();
    } 
    l.unlock();
  }
  if(isFirst) {
    fIonData->Initialise();
  }
}
 
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G4double 
G4LindhardSorensenIonModel::GetChargeSquareRatio(const G4ParticleDefinition* p,
                                                 const G4Material* mat,
                                                 G4double kinEnergy)
{
  chargeSquare = corr->EffectiveChargeSquareRatio(p, mat, kinEnergy);
  return chargeSquare;
}
 
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G4double 
G4LindhardSorensenIonModel::GetParticleCharge(const G4ParticleDefinition* p,
                                              const G4Material* mat,
                                              G4double kinEnergy)
{
  return corr->GetParticleCharge(p,mat,kinEnergy);
}
 
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void G4LindhardSorensenIonModel::SetupParameters()
{
  mass = particle->GetPDGMass();
  spin = particle->GetPDGSpin();
  charge = particle->GetPDGCharge()*inveplus;
  Zin = G4lrint(std::abs(charge));
  chargeSquare = charge*charge;
  eRatio = CLHEP::electron_mass_c2/mass;
  pRatio = CLHEP::proton_mass_c2/mass;
  const G4double aMag = 
    1./(0.5*CLHEP::eplus*CLHEP::hbar_Planck*CLHEP::c_squared);
  G4double magmom = particle->GetPDGMagneticMoment()*mass*aMag;
  magMoment2 = magmom*magmom - 1.0;
  G4double x = 0.8426*CLHEP::GeV;
  if(spin == 0.0 && mass < GeV) { x = 0.736*CLHEP::GeV; }
  else if (Zin > 1) { x /= nist->GetA27(Zin); }  
 
  formfact = 2.0*CLHEP::electron_mass_c2/(x*x);
  tlimit = 2.0/formfact;
}
 
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G4double G4LindhardSorensenIonModel::MinEnergyCut(const G4ParticleDefinition*,
                                         const G4MaterialCutsCouple* couple)
{
  return couple->GetMaterial()->GetIonisation()->GetMeanExcitationEnergy();
}
 
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G4double 
G4LindhardSorensenIonModel::ComputeCrossSectionPerElectron(
                                                  const G4ParticleDefinition* p,
                                                  G4double kinEnergy,
                                                  G4double cutEnergy,
                                                  G4double maxKinEnergy)        
{
  // take into account formfactor
  G4double tmax = MaxSecondaryEnergy(p, kinEnergy);
  G4double emax = std::min(tmax, maxKinEnergy);
  G4double escaled = kinEnergy*pRatio;
  G4double cross = (escaled <= fElimit)
    ? fBraggModel->ComputeCrossSectionPerElectron(p,kinEnergy,cutEnergy,emax)
    : fBBModel->ComputeCrossSectionPerElectron(p,kinEnergy,cutEnergy,emax);
  // G4cout << "LS: e= " << kinEnergy << " tmin= " << cutEnergy 
  //        << " tmax= " << maxEnergy << " cross= " << cross << G4endl; 
  return cross;
}
 
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G4double G4LindhardSorensenIonModel::ComputeCrossSectionPerAtom(
                                           const G4ParticleDefinition* p,
                                                 G4double kineticEnergy,
                                                 G4double Z, G4double,
                                                 G4double cutEnergy,
                                                 G4double maxEnergy)
{
  return Z*ComputeCrossSectionPerElectron(p,kineticEnergy,cutEnergy,maxEnergy);
}
 
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G4double G4LindhardSorensenIonModel::CrossSectionPerVolume(
                                           const G4Material* material,
                                           const G4ParticleDefinition* p,
                                                 G4double kineticEnergy,
                                                 G4double cutEnergy,
                                                 G4double maxEnergy)
{
  return material->GetElectronDensity()
    *ComputeCrossSectionPerElectron(p,kineticEnergy,cutEnergy,maxEnergy);
}
 
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G4double 
G4LindhardSorensenIonModel::ComputeDEDXPerVolume(const G4Material* mat,
                                                 const G4ParticleDefinition* p,
                                                 G4double kinEnergy,
                                                 G4double cut)
{
  // formfactor is taken into account in CorrectionsAlongStep(..)
  G4double tmax      = MaxSecondaryEnergy(p, kinEnergy);
  G4double cutEnergy = std::min(std::min(cut,tmax), tlimit);
 
  G4double escaled = kinEnergy*pRatio;
  G4double dedx = (escaled <= fElimit)
    ? fBraggModel->ComputeDEDXPerVolume(mat, p, kinEnergy, cutEnergy)
    : fBBModel->ComputeDEDXPerVolume(mat, p, kinEnergy, cutEnergy);
 
  //G4cout << "E(MeV)=" << kinEnergy/MeV << " dedx=" << dedx 
  //  << "  " << mat->GetName() << " Ecut(MeV)=" << cutEnergy << G4endl;
  return dedx;
}
 
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void G4LindhardSorensenIonModel::CorrectionsAlongStep(
                                 const G4MaterialCutsCouple* couple,
                                 const G4DynamicParticle* dp,
                                 const G4double& length,
                                       G4double& eloss)
{
  // no correction at the last step
  const G4double preKinEnergy = dp->GetKineticEnergy();
  if(eloss >= preKinEnergy) { return; }
 
  const G4ParticleDefinition* p = dp->GetDefinition();
  SetParticle(p);
  const G4Material* mat = couple->GetMaterial();
  const G4double eDensity = mat->GetElectronDensity();
  const G4double e = std::max(preKinEnergy - eloss*0.5, preKinEnergy*0.5);
  const G4double tmax = MaxSecondaryEnergy(p, e);
  const G4double escaled = e*pRatio;
  const G4double tau = e/mass;
  const G4double q2 = corr->EffectiveChargeSquareRatio(p, mat, e);
  const G4int Z = p->GetAtomicNumber();
 
  G4double res = 0.0;
  if(escaled <= fElimit) {
    // data from ICRU73 or ICRU90
    if(Z > 2 && Z <= 80) {
      res = fIonData->GetDEDX(mat, Z, escaled, G4Log(escaled));
      /*
    G4cout << "  GetDEDX for Z=" << Z << " in " << mat->GetName()
    << " Escaled=" << escaled << " E=" 
    << e << " dEdx=" << res << G4endl;
      */
    }
    if(res > 0.0) {
      auto pcuts = couple->GetProductionCuts();
      G4double cut = (nullptr == pcuts) ? tmax : pcuts->GetProductionCut(1);
      if(cut < tmax) {
    const G4double x = cut/tmax;
    res += (G4Log(x)*(tau + 1.)*(tau + 1.)/(tau * (tau + 2.0)) + 1.0 - x) 
      *q2*CLHEP::twopi_mc2_rcl2*eDensity;
      }
      res *= length;
    } else {
      // simplified correction
      res = eloss*q2/chargeSquare;
    }
  } else {
    // Lindhard-Sorensen model
    const G4double gam = tau + 1.0;
    const G4double beta2 = tau * (tau+2.0)/(gam*gam);
    G4double deltaL0 = 2.0*corr->BarkasCorrection(p, mat, e)*(charge-1.)/charge;
    G4double deltaL = lsdata->GetDeltaL(Zin, gam); 
 
    res = eloss + 
      CLHEP::twopi_mc2_rcl2*q2*eDensity*(deltaL+deltaL0)*length/beta2;
    /*   
    G4cout << "  E(GeV)=" << preKinEnergy/GeV << " eloss(MeV)=" << eloss
       << " L= " << eloss*beta2/(twopi_mc2_rcl2*q2*eDensity*length)
       << " dL0= " << deltaL0
       << " dL= " << deltaL << " dE(MeV)=" << res - eloss << G4endl;
    */
  }
  if(res > preKinEnergy || 2*res < eloss) { res = eloss; }
  /*
  G4cout << "  G4LindhardSorensenIonModel::CorrectionsAlongStep: E(GeV)=" 
         << preKinEnergy/GeV << " eloss(MeV)=" << eloss 
     << " res(MeV)=" << res << G4endl;
  */
  eloss = res;
}
 
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void G4LindhardSorensenIonModel::SampleSecondaries(
                      std::vector<G4DynamicParticle*>* vdp,
                                          const G4MaterialCutsCouple* couple,
                                          const G4DynamicParticle* dp,
                                          G4double cut,
                                          G4double maxEnergy)
{
  G4double kineticEnergy = dp->GetKineticEnergy();
  // take into account formfactor
  const G4double tmax = MaxSecondaryEnergy(dp->GetDefinition(), kineticEnergy);
  const G4double minKinEnergy = std::min(cut, tmax);
  const G4double maxKinEnergy = std::min(maxEnergy, tmax);
  if(minKinEnergy >= maxKinEnergy) { return; }
 
  //G4cout << "G4LindhardSorensenIonModel::SampleSecondaries Emin= " 
  // << minKinEnergy << " Emax= " << maxKinEnergy << G4endl;
 
  G4double totEnergy = kineticEnergy + mass;
  G4double etot2 = totEnergy*totEnergy;
  G4double beta2 = kineticEnergy*(kineticEnergy + 2.0*mass)/etot2;
 
  G4double deltaKinEnergy, f; 
  G4double f1 = 0.0;
  G4double fmax = 1.0;
  if( 0.0 < spin ) { fmax += 0.5*maxKinEnergy*maxKinEnergy/etot2; }
 
  CLHEP::HepRandomEngine* rndmEngineMod = G4Random::getTheEngine();
  G4double rndm[2];
 
  // sampling without nuclear size effect
  do {
    rndmEngineMod->flatArray(2, rndm);
    deltaKinEnergy = minKinEnergy*maxKinEnergy
                    /(minKinEnergy*(1.0 - rndm[0]) + maxKinEnergy*rndm[0]);
 
    f = 1.0 - beta2*deltaKinEnergy/tmax;
    if( 0.0 < spin ) {
      f1 = 0.5*deltaKinEnergy*deltaKinEnergy/etot2;
      f += f1;
    }
 
    // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
  } while( fmax*rndm[1] > f);
 
  // projectile formfactor - suppresion of high energy
  // delta-electron production at high energy
  
  G4double x = formfact*deltaKinEnergy;
  if(x > 1.e-6) {
 
    G4double x1 = 1.0 + x;
    G4double grej  = 1.0/(x1*x1);
    if( 0.0 < spin ) {
      G4double x2 = 0.5*electron_mass_c2*deltaKinEnergy/(mass*mass);
      grej *= (1.0 + magMoment2*(x2 - f1/f)/(1.0 + x2));
    }
    if(grej > 1.1) {
      G4cout << "### G4LindhardSorensenIonModel WARNING: grej= " << grej
             << "  " << dp->GetDefinition()->GetParticleName()
             << " Ekin(MeV)= " <<  kineticEnergy
             << " delEkin(MeV)= " << deltaKinEnergy
             << G4endl;
    }
    if(rndmEngineMod->flat() > grej) { return; }
  }
 
  G4ThreeVector deltaDirection;
 
  if(UseAngularGeneratorFlag()) {
 
    const G4Material* mat =  couple->GetMaterial();
    G4int Z = SelectRandomAtomNumber(mat);
 
    deltaDirection = 
      GetAngularDistribution()->SampleDirection(dp, deltaKinEnergy, Z, mat);
 
  } else {
 
    G4double deltaMomentum =
      std::sqrt(deltaKinEnergy * (deltaKinEnergy + 2.0*electron_mass_c2));
    G4double cost = deltaKinEnergy * (totEnergy + electron_mass_c2) /
      (deltaMomentum * dp->GetTotalMomentum());
    cost = std::min(cost, 1.0);
    G4double sint = std::sqrt((1.0 - cost)*(1.0 + cost));
 
    G4double phi = CLHEP::twopi*rndmEngineMod->flat();
 
    deltaDirection.set(sint*std::cos(phi),sint*std::sin(phi), cost) ;
    deltaDirection.rotateUz(dp->GetMomentumDirection());
  }  
  /*
    G4cout << "### G4LindhardSorensenIonModel " 
           << dp->GetDefinition()->GetParticleName()
           << " Ekin(MeV)= " <<  kineticEnergy
           << " delEkin(MeV)= " << deltaKinEnergy
           << " tmin(MeV)= " << minKinEnergy
           << " tmax(MeV)= " << maxKinEnergy
           << " dir= " << dp->GetMomentumDirection()
           << " dirDelta= " << deltaDirection
           << G4endl;
  */
  // create G4DynamicParticle object for delta ray
  auto delta = new G4DynamicParticle(theElectron,deltaDirection,deltaKinEnergy);
 
  vdp->push_back(delta);
 
  // Change kinematics of primary particle
  kineticEnergy -= deltaKinEnergy;
  G4ThreeVector finalP = dp->GetMomentum() - delta->GetMomentum();
  finalP = finalP.unit();
  
  fParticleChange->SetProposedKineticEnergy(kineticEnergy);
  fParticleChange->SetProposedMomentumDirection(finalP);
}
 
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G4double 
G4LindhardSorensenIonModel::MaxSecondaryEnergy(const G4ParticleDefinition* pd,
                                               G4double kinEnergy) 
{
  // here particle type is checked for any method
  SetParticle(pd);
  G4double tau  = kinEnergy/mass;
  return 2.0*CLHEP::electron_mass_c2*tau*(tau + 2.) /
    (1. + 2.0*(tau + 1.)*eRatio + eRatio*eRatio);
}
 
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