G4HadronElasticProcess.cc

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// Geant4 Hadron Elastic Scattering Process 
// 
// Created 26 July 2012 V.Ivanchenko from G4WHadronElasticProcess
//  
// Modified:
// 14-Sep-12 M.Kelsey -- Pass subType code to base ctor
 
#include <iostream>
 
#include "G4HadronElasticProcess.hh"
#include "G4SystemOfUnits.hh"
#include "G4Nucleus.hh"
#include "G4ProcessManager.hh"
#include "G4CrossSectionDataStore.hh"
#include "G4ProductionCutsTable.hh"
#include "G4HadronicException.hh"
#include "G4HadronicInteraction.hh"
#include "G4VCrossSectionRatio.hh"
#include "G4PhysicsModelCatalog.hh"
 
G4HadronElasticProcess::G4HadronElasticProcess(const G4String& pName)
  : G4HadronicProcess(pName, fHadronElastic), 
    fDiffraction(nullptr), fDiffractionRatio(nullptr)
{}
 
G4HadronElasticProcess::~G4HadronElasticProcess()
{}
 
void G4HadronElasticProcess::ProcessDescription(std::ostream& outFile) const
{
  outFile << "G4HadronElasticProcess handles the elastic scattering of \n"
      << "hadrons by invoking the following hadronic model(s) and \n"
      << "hadronic cross section(s).\n";
}
 
G4VParticleChange* 
G4HadronElasticProcess::PostStepDoIt(const G4Track& track, 
                     const G4Step&)
{
  theTotalResult->Clear();
  theTotalResult->Initialize(track);
  G4double weight = track.GetWeight();
  theTotalResult->ProposeWeight(weight);
 
  // For elastic scattering, _any_ result is considered an interaction
  theNumberOfInteractionLengthLeft = -1.0;
 
  const G4DynamicParticle* dynParticle = track.GetDynamicParticle();
  G4double kineticEnergy = dynParticle->GetKineticEnergy();
  G4TrackStatus status = track.GetTrackStatus();
  if(kineticEnergy == 0.0 || track.GetTrackStatus() != fAlive) {
    return theTotalResult;
  }
 
  const G4Material* material = track.GetMaterial();
 
  // check only for charged particles
  if(fXSType != fHadNoIntegral) {
    mfpKinEnergy = DBL_MAX;
    G4double xs = aScaleFactor*
      theCrossSectionDataStore->ComputeCrossSection(dynParticle, material);
    if(xs < theLastCrossSection*G4UniformRand()) {
      // No interaction
      return theTotalResult;
    }    
  }
 
  const G4ParticleDefinition* part = dynParticle->GetDefinition();
  G4Nucleus* targNucleus = GetTargetNucleusPointer();
 
  // Select element
  const G4Element* elm = 
    theCrossSectionDataStore->SampleZandA(dynParticle, material, *targNucleus);
 
  // Initialize the hadronic projectile from the track
  G4HadProjectile theProj(track);
  G4HadronicInteraction* hadi = nullptr;
  G4HadFinalState* result = nullptr;
 
  if(nullptr != fDiffraction) {
    G4double ratio = 
      fDiffractionRatio->ComputeRatio(part, kineticEnergy,
                      targNucleus->GetZ_asInt(),
                      targNucleus->GetA_asInt());
    // diffraction is chosen
    if(ratio > 0.0 && G4UniformRand() < ratio) 
    {
      try
    {
      result = fDiffraction->ApplyYourself(theProj, *targNucleus);
    }
      catch(G4HadronicException & aR)
    {
      G4ExceptionDescription ed;
      aR.Report(ed);
      ed << "Call for " << fDiffraction->GetModelName() << G4endl;
      ed << part->GetParticleName() 
         << " off target element " << elm->GetName() << "  Z= " 
         << targNucleus->GetZ_asInt() 
         << "  A= " << targNucleus->GetA_asInt() << G4endl;
      DumpState(track,"ApplyYourself",ed);
      ed << " ApplyYourself failed" << G4endl;
      G4Exception("G4HadronElasticProcess::PostStepDoIt", "had006", 
              FatalException, ed);
    }
      // Check the result for catastrophic energy non-conservation
      result = CheckResult(theProj, *targNucleus, result);
      result->SetTrafoToLab(theProj.GetTrafoToLab());
 
      // The following method of the base class takes care also of setting
      // the creator model ID for the secondaries that are created
      FillResult(result, track);
 
      if (epReportLevel != 0) {
    CheckEnergyMomentumConservation(track, *targNucleus);
      }
      return theTotalResult;
    }
  }      
 
  // ordinary elastic scattering
  hadi = ChooseHadronicInteraction( theProj, *targNucleus, material, elm );
  if(nullptr == hadi) {
    G4ExceptionDescription ed;
    ed << part->GetParticleName() 
       << " off target element " << elm->GetName() << "  Z= " 
       << targNucleus->GetZ_asInt() << "  A= " 
       << targNucleus->GetA_asInt() << G4endl;
    DumpState(track,"ChooseHadronicInteraction",ed);
    ed << " No HadronicInteraction found out" << G4endl;
    G4Exception("G4HadronElasticProcess::PostStepDoIt", "had005", 
        FatalException, ed);
    return theTotalResult;
  }
 
  size_t idx = track.GetMaterialCutsCouple()->GetIndex();
  G4double tcut = (*(G4ProductionCutsTable::GetProductionCutsTable()
             ->GetEnergyCutsVector(3)))[idx];
  hadi->SetRecoilEnergyThreshold(tcut);
  /*
  if(verboseLevel>1) {
    G4cout << "G4HadronElasticProcess::PostStepDoIt for " 
       << part->GetParticleName()
       << " in " << material->GetName() 
       << " Target Z= " << targNucleus->GetZ_asInt() 
       << " A= " << targNucleus->GetA_asInt() 
       << " Tcut(MeV)= " << tcut << G4endl; 
  }
  */
  result = hadi->ApplyYourself( theProj, *targNucleus);
 
  // Check the result for catastrophic energy non-conservation
  // cannot be applied because is not guranteed that recoil 
  // nucleus is created
  // result = CheckResult(theProj, targNucleus, result);
 
  // directions
  G4ThreeVector indir = track.GetMomentumDirection();
  G4ThreeVector outdir = result->GetMomentumChange();
  /*
  if(verboseLevel>1) {
    G4cout << "Efin= " << result->GetEnergyChange()
       << " de= " << result->GetLocalEnergyDeposit()
       << " nsec= " << result->GetNumberOfSecondaries()
       << " dir= " << outdir
       << G4endl;
  }
  */
  // energies  
  G4double edep = std::max(result->GetLocalEnergyDeposit(), 0.0);
  G4double efinal = std::max(result->GetEnergyChange(), 0.0);
 
  // primary change
  theTotalResult->ProposeEnergy(efinal);
 
  if(efinal > 0.0) {
    outdir.rotateUz(indir);
    theTotalResult->ProposeMomentumDirection(outdir);
  } else {
    if(part->GetProcessManager()->GetAtRestProcessVector()->size() > 0)
         { status = fStopButAlive; }
    else { status = fStopAndKill; }
    theTotalResult->ProposeTrackStatus(status);
  }
  /*
  G4cout << "Efinal= " << efinal << "  TrackStatus= " << status 
     << " time(ns)=" << track.GetGlobalTime()/ns << G4endl;
  */
  theTotalResult->SetNumberOfSecondaries(0);
 
  // recoil
  if(result->GetNumberOfSecondaries() > 0) {
    G4DynamicParticle* p = result->GetSecondary(0)->GetParticle();
 
    if(p->GetKineticEnergy() > tcut) {
      theTotalResult->SetNumberOfSecondaries(1);
      G4ThreeVector pdir = p->GetMomentumDirection();
      // G4cout << "recoil " << pdir << G4endl;
      pdir.rotateUz(indir);
      // G4cout << "recoil rotated " << pdir << G4endl;
      p->SetMomentumDirection(pdir);
 
      // in elastic scattering time and weight are not changed
      G4Track* t = new G4Track(p, track.GetGlobalTime(), 
                   track.GetPosition());
      t->SetWeight(weight);
      t->SetTouchableHandle(track.GetTouchableHandle());
      G4int secID = G4PhysicsModelCatalog::GetModelID( "model_" + hadi->GetModelName() );
      if ( secID > 0 ) t->SetCreatorModelID(secID);
      theTotalResult->AddSecondary(t);
 
    } else {
      edep += p->GetKineticEnergy();
      delete p;
    }
  }
  theTotalResult->ProposeLocalEnergyDeposit(edep);
  theTotalResult->ProposeNonIonizingEnergyDeposit(edep);
  result->Clear();
 
  return theTotalResult;
}
 
void G4HadronElasticProcess::SetLowestEnergy(G4double)
{
  PrintWarning("G4HadronElasticProcess::SetLowestEnergy(..) ");
}
 
void 
G4HadronElasticProcess::SetLowestEnergyNeutron(G4double)
{
  PrintWarning("G4HadronElasticProcess::SetLowestEnergyNeutron(..) ");
}
 
void G4HadronElasticProcess::SetDiffraction(G4HadronicInteraction* hi, 
                        G4VCrossSectionRatio* xsr)
{
  if(hi && xsr) {
    fDiffraction = hi;
    fDiffractionRatio = xsr;
  }
}
 
void G4HadronElasticProcess::PrintWarning(const G4String& tit) const
{
  G4Exception(tit, "had003", JustWarning, 
  " method is obsolete and will be removed in the next release");
}