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// $Id: G4VAtomDeexcitation.cc,v 1.3 2010/11/04 12:55:09 vnivanch Exp $
// GEANT4 tag $Name: emutils-V09-03-23 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class class file
//
//
// File name:     G4VAtomDeexcitation
//
// Author:        Alfonso Mantero & Vladimir Ivanchenko
//
// Creation date: 21.04.2010
//
// Modifications:
//
// Class Description:
//
// Abstract interface to energy loss models

// -------------------------------------------------------------------
//

#include "G4VAtomDeexcitation.hh"
#include "G4ParticleDefinition.hh"
#include "G4DynamicParticle.hh"
#include "G4Step.hh"
#include "G4Region.hh"
#include "G4RegionStore.hh"
#include "G4MaterialCutsCouple.hh"
#include "G4MaterialCutsCouple.hh"
#include "G4Material.hh"
#include "G4Element.hh"
#include "G4ElementVector.hh"
#include "Randomize.hh"
#include "G4VParticleChange.hh"

G4VAtomDeexcitation::G4VAtomDeexcitation(const G4String& modname, 
					 const G4String& pname) 
  : verbose(1), name(modname), namePIXE(pname)
{
  activeZ.resize(93, false);
  vdyn.reserve(5);
  secVect.reserve(5);
  theCoupleTable = 0;
}

G4VAtomDeexcitation::~G4VAtomDeexcitation()
{}

void G4VAtomDeexcitation::InitialiseAtomicDeexcitation()
{
  // Define list of couples
  theCoupleTable = G4ProductionCutsTable::GetProductionCutsTable();
  size_t numOfCouples = theCoupleTable->GetTableSize();
  activeDeexcitationMedia.resize(numOfCouples, false);

  // Define list of regions
  G4RegionStore* regionStore = G4RegionStore::GetInstance();
  size_t nRegions = regionStore->size();

  // There is no active regions
  if(0 == nRegions) { return; }

  if(0 < verbose) {
    G4cout << "### ================ Deexcitation model " << name 
	   << " is activated for regions:" << G4endl;  
  }

  // Identify active media
  for(size_t j=0; j<nRegions; ++j) {
    const G4Region* reg = regionStore->GetRegion(activeRegions[j], false);
    const G4ProductionCuts* rpcuts = reg->GetProductionCuts();
    if(0 < verbose) {
      G4cout << "###                   " << activeRegions[j] << G4endl;  
    }
  
    for(size_t i=0; i<numOfCouples; ++i) {
      if( !activeDeexcitationMedia[i] ) {

	const G4MaterialCutsCouple* couple =
	  theCoupleTable->GetMaterialCutsCouple(i);
	if (couple->GetProductionCuts() == rpcuts) {
	  activeDeexcitationMedia[i] = true;
          const G4Material* mat = couple->GetMaterial();
	  const G4ElementVector* theElementVector = 
	    mat->GetElementVector();
          G4int Z = (G4int)((*theElementVector)[i])->GetZ();
          activeZ[Z] = true;
	}
      }
    }
  }

  if(0 < verbose) {
    G4cout << "### ================ PIXE model " << namePIXE 
	   << G4endl;  
  }

  // Initialise derived class
  InitialiseForNewRun();
}

void 
G4VAtomDeexcitation::SetDeexcitationActiveRegion(const G4String& rname)
{
  G4String s = rname;
  if(s == "" || s == "world" || s == "World" || s == "WORLD") {
    s = "DefaultRegionForTheWorld";
  }
  size_t n = activeRegions.size();
  if(n > 0) {
    for(size_t i=0; i<n; ++i) { if(s == activeRegions[i]) { return; } }
  }
  activeRegions.push_back(s);
}

void 
G4VAtomDeexcitation::AlongStepDeexcitation(G4VParticleChange* pParticleChange,
					   const G4Step& step, 
					   G4double& eLoss,
                                           G4int coupleIndex)
{
  if(!CheckDeexcitationActiveRegion(coupleIndex) || eLoss == 0.0) { return; }

  // step parameters
  const G4StepPoint* preStep = step.GetPreStepPoint();
  G4ThreeVector prePos = preStep->GetPosition();
  G4ThreeVector delta = step.GetPostStepPoint()->GetPosition() - prePos;
  G4double preTime = preStep->GetGlobalTime();
  G4double dt = step.GetPostStepPoint()->GetGlobalTime() - preTime;
  G4double truelength = step.GetStepLength();

  // particle parameters
  const G4Track* track = step.GetTrack();
  const G4ParticleDefinition* part = track->GetDefinition();
  G4double ekin = preStep->GetKineticEnergy() - 0.5*eLoss;

  // media parameters
  G4double gCut = (*theCoupleTable->GetEnergyCutsVector(coupleIndex))[0];
  G4double eCut = (*theCoupleTable->GetEnergyCutsVector(coupleIndex))[1];
  const G4Material* material = preStep->GetMaterial();
  const G4ElementVector* theElementVector = material->GetElementVector();
  const G4double* theAtomNumDensityVector = material->GetVecNbOfAtomsPerVolume();
  G4int nelm = material->GetNumberOfElements();

  // loop over deexcitations
  for(G4int i=0; i<nelm; ++i) {
    G4int Z = G4int((*theElementVector)[i]->GetZ());
    if(Z > 5) {
      G4double x = truelength*theAtomNumDensityVector[i];
      if(x > 0.0) {
	for(G4int ii=0; ii<9; ++ii) {
          G4AtomicShellEnumerator as = G4AtomicShellEnumerator(ii);
	  const G4AtomicShell* shell = GetAtomicShell(Z, as);
	  if(gCut < shell->BindingEnergy()) {
	    G4double mfp = 
	      GetShellIonisationCrossSectionPerAtom(part, Z, as, ekin); 

	    // mfp is mean free path in units of step size
	    if(mfp > 0.0) {
	      mfp = 1.0/(x*mfp);
	      G4double stot = 0.0;

	      // sample ionisation points
	      do {
		stot -= mfp*std::log(G4UniformRand());
		if( stot > 1.0) { break; }

		// sample deexcitation
		vdyn.clear();
		GenerateParticles(&vdyn, shell, Z, gCut, eCut); 
		G4int nsec = vdyn.size();
                if(nsec > 0) {
		  secVect.clear();
                  G4ThreeVector r = prePos  + stot*delta;
                  G4double time   = preTime + stot*dt;
                  for(G4int j=0; j<nsec; ++j) {
                    G4DynamicParticle* dp = vdyn[j];
                    G4double e = dp->GetKineticEnergy();

		    // save new secondary if there is enough energy
                    if(e <= eLoss) {
		      G4Track* t = new G4Track(dp, time, r);
		      secVect.push_back(t); 
                      eLoss -= e;
		    } else {
                      delete dp;
		    }                   
		  }
		}
	      } while ( stot < 1.0 && eLoss > 0.0);
	    }
	  }
	}
      } 
    }
  }
  G4int nsec = secVect.size(); 
  if(nsec > 0) {
    G4int secondariesBefore = pParticleChange->GetNumberOfSecondaries();
    pParticleChange->SetNumberOfSecondaries(nsec+secondariesBefore);
    for(G4int j=0; j<nsec; ++j) {
      pParticleChange->AddSecondary(secVect[j]);
    }
  }
}