G4InelasticInteraction.cc

Go to the documentation of this file.

//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
// $Id$
//
// Hadronic Process: Inelastic Interaction 
// original by H.P. Wellisch
// modified by J.L. Chuma, TRIUMF, 22-Nov-1996
// Last modified: 27-Mar-1997
// J.P. Wellisch: 23-Apr-97: throw G4HadronicException(__FILE__, __LINE__,  removed
// J.P. Wellisch: 24-Apr-97: correction for SetUpPions
// Modified by J.L. Chuma, 30-Apr-97: added originalTarget to CalculateMomenta
//                                    since TwoBody needed to reset the target particle
// J.L. Chuma, 20-Jun-97: Modified CalculateMomenta to correct the decision process
//                        for whether to use GenerateXandPt or TwoCluster
// J.L. Chuma, 06-Aug-97: added original incident particle, before Fermi motion and
//                        evaporation effects are included, needed for calculating
//                        self absorption and corrections for single particle spectra
// HPW removed misunderstanding of LocalEnergyDeposit, 11.04.98.
// 23-Jan-2009 V.Ivanchenko move constructor and destructor to the body
 
#include "G4InelasticInteraction.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"
#include "G4HadReentrentException.hh"
#include "G4IsoResult.hh"
#include "G4IsoParticleChange.hh"
 
G4IsoParticleChange* G4InelasticInteraction::theIsoResult = 0;
G4IsoParticleChange* G4InelasticInteraction::theOldIsoResult = 0;
 
G4InelasticInteraction::G4InelasticInteraction(const G4String& name) 
 : G4HadronicInteraction(name), isotopeProduction(false), cache(0.0)
{}
  
G4InelasticInteraction::~G4InelasticInteraction()
{}
 
// Pmltpc used in Cascade functions
G4double
G4InelasticInteraction::Pmltpc(G4int npos, G4int nneg, G4int nzero, G4int n,
                               G4double b, G4double c)
{
  const G4double expxu = 82.;       // upper bound for arg. of exp
  const G4double expxl = -expxu;    // lower bound for arg. of exp
  G4double npf = 0.0;
  G4double nmf = 0.0;
  G4double nzf = 0.0;
  G4int i;
  for (i = 2; i <= npos; i++) npf += std::log((G4double)i);
  for (i = 2; i <= nneg; i++) nmf += std::log((G4double)i);
  for (i = 2; i <= nzero; i++) nzf += std::log((G4double)i);
  G4double r = std::min(expxu, std::max(expxl,
                        -(npos-nneg+nzero+b)*(npos-nneg+nzero+b)/(2*c*c*n*n)
                        - npf - nmf - nzf ) );
  return std::exp(r);
}
 
 
G4bool G4InelasticInteraction::MarkLeadingStrangeParticle(
                                 const G4ReactionProduct& currentParticle,
                                 const G4ReactionProduct& targetParticle,
                                 G4ReactionProduct& leadParticle)
{
  // the following was in GenerateXandPt and TwoCluster
  // add a parameter to the GenerateXandPt function telling it about the strange particle
  //
  // assumes that the original particle was a strange particle
  //
  G4bool lead = false;
  if ((currentParticle.GetMass() >= G4KaonPlus::KaonPlus()->GetPDGMass()) &&
      (currentParticle.GetDefinition() != G4Proton::Proton()) &&
      (currentParticle.GetDefinition() != G4Neutron::Neutron()) ) {
      lead = true;
      leadParticle = currentParticle;    // set lead to the incident particle
 
  } else if ((targetParticle.GetMass() >= G4KaonPlus::KaonPlus()->GetPDGMass()) &&
             (targetParticle.GetDefinition() != G4Proton::Proton()) &&
             (targetParticle.GetDefinition() != G4Neutron::Neutron() ) ) {
    lead = true;
    leadParticle = targetParticle;              //   set lead to the target particle
  }
 
  return lead;
}
 
 
void
G4InelasticInteraction::SetUpPions(const G4int npos, const G4int nneg,
                                   const G4int nzero,
                                   G4FastVector<G4ReactionProduct,GHADLISTSIZE>& vec,
                                   G4int& vecLen)
{
  if (npos + nneg + nzero == 0) return;
  G4int i;
  G4ReactionProduct* p;
 
  for (i = 0; i < npos; ++i) {
    p = new G4ReactionProduct;
    p->SetDefinition( G4PionPlus::PionPlus() );
    (G4UniformRand() < 0.5) ? p->SetSide( -1 ) : p->SetSide( 1 );
    vec.SetElement( vecLen++, p );
  }
  for (i = npos; i < npos+nneg; ++i) {
    p = new G4ReactionProduct;
    p->SetDefinition( G4PionMinus::PionMinus() );
    (G4UniformRand() < 0.5) ? p->SetSide(-1) : p->SetSide(1);
    vec.SetElement( vecLen++, p );
  }
  for (i = npos+nneg; i < npos+nneg+nzero; ++i) {
    p = new G4ReactionProduct;
    p->SetDefinition( G4PionZero::PionZero() );
    (G4UniformRand() < 0.5) ? p->SetSide(-1) : p->SetSide(1);
    vec.SetElement( vecLen++, p );
  }
}
 
 
void
  G4InelasticInteraction::GetNormalizationConstant(
   const G4double energy,  // MeV,  <0 means annihilation channels
   G4double &n,
   G4double &anpn )
  {
    const G4double expxu =  82.;          // upper bound for arg. of exp
    const G4double expxl = -expxu;        // lower bound for arg. of exp
    const G4int numSec = 60;
    //
    // the only difference between the calculation for annihilation channels
    // and normal is the starting value, iBegin, for the loop below
    //
    G4int iBegin = 1;
    G4double en = energy;
    if( energy < 0.0 )
    {
      iBegin = 2;
      en *= -1.0;
    }
    //
    // number of total particles vs. centre of mass Energy - 2*proton mass
    //
    G4double aleab = std::log(en/GeV);
    n = 3.62567 + aleab*(0.665843 + aleab*(0.336514 + aleab*(0.117712 + 0.0136912*aleab)));
    n -= 2.0;
    //
    // normalization constant for kno-distribution
    //
    anpn = 0.0;
    G4double test, temp;
    for( G4int i=iBegin; i<=numSec; ++i )
    {
      temp = pi*i/(2.0*n*n);
      test = std::exp( std::min( expxu, std::max( expxl, -(pi/4.0)*(i*i)/(n*n) ) ) );
      if( temp < 1.0 )
      {
        if( test >= 1.0e-10 )anpn += temp*test;
      }
      else
        anpn += temp*test;
    }
  }
 
void G4InelasticInteraction::CalculateMomenta(
                    G4FastVector<G4ReactionProduct,GHADLISTSIZE>& vec,
                    G4int& vecLen,
                    const G4HadProjectile* originalIncident,
                    const G4DynamicParticle* originalTarget,
                    G4ReactionProduct& modifiedOriginal,   // Fermi motion and evap. effects included
                    G4Nucleus& targetNucleus,
                    G4ReactionProduct& currentParticle,
                    G4ReactionProduct& targetParticle,
                    G4bool& incidentHasChanged,
                    G4bool& targetHasChanged,
                    G4bool quasiElastic)
{
  cache = 0;
  what = originalIncident->Get4Momentum().vect();
 
  theReactionDynamics.ProduceStrangeParticlePairs(vec, vecLen, modifiedOriginal,
                                                  originalTarget, currentParticle,
                                                  targetParticle, incidentHasChanged,
                                                  targetHasChanged);
 
  if (quasiElastic) {
    theReactionDynamics.TwoBody(vec, vecLen,
                                modifiedOriginal, originalTarget,
                                currentParticle, targetParticle,
                                targetNucleus, targetHasChanged);
    return;
  }
  G4ReactionProduct leadingStrangeParticle;
  G4bool leadFlag = MarkLeadingStrangeParticle(currentParticle,
                                               targetParticle,
                                               leadingStrangeParticle);
 
  // Note: the number of secondaries can be reduced in GenerateXandPt and TwoCluster
  G4bool finishedGenXPt = false;
  G4bool annihilation = false;
    if( originalIncident->GetDefinition()->GetPDGEncoding() < 0 &&
        currentParticle.GetMass() == 0.0 && targetParticle.GetMass() == 0.0 )
    {
      // original was an anti-particle and annihilation has taken place
      annihilation = true;
      G4double ekcor = 1.0;
      G4double ek = originalIncident->GetKineticEnergy();
      G4double ekOrg = ek;
      
      const G4double tarmas = originalTarget->GetDefinition()->GetPDGMass();
      if( ek > 1.0*GeV )ekcor = 1./(ek/GeV);
      const G4double atomicWeight = targetNucleus.GetA_asInt();
      ek = 2*tarmas + ek*(1.+ekcor/atomicWeight);
      G4double tkin = targetNucleus.Cinema(ek);
      ek += tkin;
      ekOrg += tkin;
      //      modifiedOriginal.SetKineticEnergy( ekOrg );
      //
      // evaporation --  re-calculate black track energies
      //                 this was Done already just before the cascade
      //
      tkin = targetNucleus.AnnihilationEvaporationEffects(ek, ekOrg);
      ekOrg -= tkin;
      ekOrg = std::max( 0.0001*GeV, ekOrg );
      modifiedOriginal.SetKineticEnergy( ekOrg );
      G4double amas = originalIncident->GetDefinition()->GetPDGMass();
      G4double et = ekOrg + amas;
      G4double p = std::sqrt( std::abs(et*et-amas*amas) );
      G4double pp = modifiedOriginal.GetMomentum().mag();
      if( pp > 0.0 )
      {
        G4ThreeVector momentum = modifiedOriginal.GetMomentum();
        modifiedOriginal.SetMomentum( momentum * (p/pp) );
      }
      if( ekOrg <= 0.0001 )
      {
        modifiedOriginal.SetKineticEnergy( 0.0 );
        modifiedOriginal.SetMomentum( 0.0, 0.0, 0.0 );
      }
    }
    const G4double twsup[] = { 1.0, 0.7, 0.5, 0.3, 0.2, 0.1 };
    G4double rand1 = G4UniformRand();
    G4double rand2 = G4UniformRand();
 
    // Cache current, target, and secondaries
    G4ReactionProduct saveCurrent = currentParticle;
    G4ReactionProduct saveTarget = targetParticle;
    std::vector<G4ReactionProduct> savevec;
    for (G4int i = 0; i < vecLen; i++) savevec.push_back(*vec[i]);
 
    if (annihilation || 
        vecLen >= 6 ||
        ( modifiedOriginal.GetKineticEnergy()/GeV >= 1.0 &&
          ( ( (originalIncident->GetDefinition() == G4KaonPlus::KaonPlus() ||
               originalIncident->GetDefinition() == G4KaonMinus::KaonMinus() ||
               originalIncident->GetDefinition() == G4KaonZeroLong::KaonZeroLong() ||
               originalIncident->GetDefinition() == G4KaonZeroShort::KaonZeroShort() ) 
               &&
           rand1 < 0.5 ) 
        || rand2 > twsup[vecLen] )  )  )
 
      finishedGenXPt =
        theReactionDynamics.GenerateXandPt( vec, vecLen,
                                            modifiedOriginal, originalIncident,
                                            currentParticle, targetParticle,
                                            originalTarget,
                                            targetNucleus, incidentHasChanged,
                                            targetHasChanged, leadFlag,
                                            leadingStrangeParticle );
    if( finishedGenXPt )
    {
      Rotate(vec, vecLen);
      return;
    }
 
    G4bool finishedTwoClu = false;
    if( modifiedOriginal.GetTotalMomentum()/MeV < 1.0 )
    {
      for(G4int i=0; i<vecLen; i++) delete vec[i];
      vecLen = 0;
    }
    else
    {
      // Occaisionally, GenerateXandPt will fail in the annihilation channel.
      // Restore current, target and secondaries to pre-GenerateXandPt state
      // before trying annihilation in TwoCluster
 
      if (!finishedGenXPt && annihilation) {
        currentParticle = saveCurrent;
        targetParticle = saveTarget;
        for (G4int i = 0; i < vecLen; i++) delete vec[i];
        vecLen = 0;
        vec.Initialize( 0 );
        for (G4int i = 0; i < G4int(savevec.size()); i++) {
          G4ReactionProduct* p = new G4ReactionProduct;
          *p = savevec[i];
          vec.SetElement( vecLen++, p );
        }
      }
 
      theReactionDynamics.SuppressChargedPions( vec, vecLen,
                                      modifiedOriginal, currentParticle,
                                      targetParticle, targetNucleus,
                                      incidentHasChanged, targetHasChanged );
      try
      {
      finishedTwoClu = theReactionDynamics.TwoCluster( vec, vecLen,
                                      modifiedOriginal, originalIncident,
                                      currentParticle, targetParticle,
                                      originalTarget,
                                      targetNucleus, incidentHasChanged,
                                      targetHasChanged, leadFlag,
                                      leadingStrangeParticle );
       }
       catch(G4HadReentrentException aC)
       {
         aC.Report(G4cout);
     throw G4HadReentrentException(__FILE__, __LINE__, "Failing to calculate momenta");
       }
    }
 
  if (finishedTwoClu) {
    Rotate(vec, vecLen);
    return;
  }
 
  theReactionDynamics.TwoBody(vec, vecLen, modifiedOriginal, originalTarget,
                              currentParticle, targetParticle,
                              targetNucleus, targetHasChanged);
}
 
 
void G4InelasticInteraction::Rotate(
   G4FastVector<G4ReactionProduct,GHADLISTSIZE>& vec, G4int& vecLen)
{
  G4double rotation = 2.*pi*G4UniformRand();
  cache = rotation;
  G4int i;
  for (i = 0; i < vecLen; ++i) {
    G4ThreeVector momentum = vec[i]->GetMomentum();
    momentum = momentum.rotate(rotation, what);
    vec[i]->SetMomentum(momentum);
  }
}      
 
 
void G4InelasticInteraction::SetUpChange(
   G4FastVector<G4ReactionProduct,GHADLISTSIZE>& vec,
   G4int& vecLen,
   G4ReactionProduct& currentParticle,
   G4ReactionProduct& targetParticle,
   G4bool& incidentHasChanged)
{
  theParticleChange.Clear();
  G4ParticleDefinition* aKaonZL = G4KaonZeroLong::KaonZeroLong();
  G4ParticleDefinition* aKaonZS = G4KaonZeroShort::KaonZeroShort();
  G4int i;
  if (currentParticle.GetDefinition() == aKaonZL) {
    if (G4UniformRand() <= 0.5) {
      currentParticle.SetDefinition(aKaonZS);
      incidentHasChanged = true;
    }
  } else if (currentParticle.GetDefinition() == aKaonZS) {
    if (G4UniformRand() > 0.5) {
      currentParticle.SetDefinition(aKaonZL);
      incidentHasChanged = true;
    }
  }
 
  if (targetParticle.GetDefinition() == aKaonZL) {
    if (G4UniformRand() <= 0.5) targetParticle.SetDefinition(aKaonZS);
  } else if (targetParticle.GetDefinition() == aKaonZS) {
    if (G4UniformRand() > 0.5 ) targetParticle.SetDefinition(aKaonZL);
  }
 
  for (i = 0; i < vecLen; ++i) {
    if (vec[i]->GetDefinition() == aKaonZL) {
      if( G4UniformRand() <= 0.5) vec[i]->SetDefinition(aKaonZS);
    } else if (vec[i]->GetDefinition() == aKaonZS) {
      if (G4UniformRand() > 0.5) vec[i]->SetDefinition(aKaonZL);
    }
  }
 
  if (incidentHasChanged) {
    G4DynamicParticle* p0 = new G4DynamicParticle;
    p0->SetDefinition( currentParticle.GetDefinition() );
    p0->SetMomentum( currentParticle.GetMomentum() );
    theParticleChange.AddSecondary( p0 );
    theParticleChange.SetStatusChange( stopAndKill );
    theParticleChange.SetEnergyChange( 0.0 );
  } else {
    G4double p = currentParticle.GetMomentum().mag()/MeV;
    G4ThreeVector pvec = currentParticle.GetMomentum();
    if (p > DBL_MIN)
      theParticleChange.SetMomentumChange(pvec.x()/p, pvec.y()/p, pvec.z()/p);
    else
      theParticleChange.SetMomentumChange(1.0, 0.0, 0.0);
 
    G4double aE = currentParticle.GetKineticEnergy();
    if (std::fabs(aE) < .1*eV) aE = .1*eV;
    theParticleChange.SetEnergyChange(aE);
  }
 
  if (targetParticle.GetMass() > 0.0) {
    // targetParticle can be eliminated in TwoBody
    G4DynamicParticle* p1 = new G4DynamicParticle;
    p1->SetDefinition(targetParticle.GetDefinition() );
    G4ThreeVector momentum = targetParticle.GetMomentum();
    momentum = momentum.rotate(cache, what);
    p1->SetMomentum(momentum);
    theParticleChange.AddSecondary(p1);
  }
 
  G4DynamicParticle* p;
  for (i = 0; i < vecLen; ++i) {
    p = new G4DynamicParticle(vec[i]->GetDefinition(), vec[i]->GetMomentum() );
    theParticleChange.AddSecondary( p );
    delete vec[i];
  }
}
 
 
G4IsoParticleChange* G4InelasticInteraction::GetIsotopeProductionInfo() 
{ 
  G4IsoParticleChange* anIsoResult = theIsoResult;
  if(theIsoResult) theOldIsoResult = theIsoResult;
  theIsoResult = 0;
  return anIsoResult;
}
 
 
void
G4InelasticInteraction::DoIsotopeCounting(const G4HadProjectile* theProjectile,
                                          const G4Nucleus& aNucleus)
{
  delete theOldIsoResult;
  theOldIsoResult = 0;
  delete theIsoResult;
  theIsoResult = new G4IsoParticleChange;
  G4IsoResult* anIsoResult = 0;
  G4int nModels = theProductionModels.size();
  if (nModels > 0) {
    for (G4int i = 0; i < nModels; i++) {
      anIsoResult = theProductionModels[i]->GetIsotope(theProjectile, aNucleus);
      if (anIsoResult) break;  // accept first result
    }
    if (!anIsoResult) anIsoResult = ExtractResidualNucleus(aNucleus);
  } else {
    // No production models active, use default iso production
    anIsoResult = ExtractResidualNucleus(aNucleus);
  }
 
/*
  G4cout << " contents of anIsoResult (from ExtractResidualNucleus) " << G4endl;
  G4cout << " original projectile: "
         << theProjectile->GetDefinition()->GetParticleName() << G4endl;
  G4cout << " mother nucleus: "
         << anIsoResult->GetMotherNucleus().GetA_asInt() << ","
         << anIsoResult->GetMotherNucleus().GetZ_asInt() << G4endl;
  G4cout << " extracted nucleus = " << anIsoResult->GetIsotope() << G4endl;
  G4cout << " end contents of anIsoResult " << G4endl;
*/
  // Add all info explicitly and add typename from model called.
  theIsoResult->SetIsotope(anIsoResult->GetIsotope());
  theIsoResult->SetProductionTime(theProjectile->GetGlobalTime() );
  theIsoResult->SetParentParticle(theProjectile->GetDefinition() );
  theIsoResult->SetMotherNucleus(anIsoResult->GetMotherNucleus());
  theIsoResult->SetProducer(this->GetModelName() );
 
  delete anIsoResult;
 
  // If isotope production is enabled the GetIsotopeProductionInfo() 
  // method must be called or else a memory leak will result
  //
  // The following code will fix the memory leak, but remove the 
  // isotope information:
  //
  //  if(theIsoResult) {
  //    delete theIsoResult;
  //    theIsoResult = 0;
  //  }
}
 
 
G4IsoResult*
G4InelasticInteraction::ExtractResidualNucleus(const G4Nucleus& aNucleus)
{
  G4double A = aNucleus.GetA_asInt();
  G4double Z = aNucleus.GetZ_asInt();
  G4double bufferA = 0;
  G4double bufferZ = 0;
 
  // Loop over theParticleChange, decrement A, Z accordingly, and
  // cache the largest fragment
  for (G4int i = 0; i < theParticleChange.GetNumberOfSecondaries(); ++i) {
    G4HadSecondary* aSecTrack = theParticleChange.GetSecondary(i);
    const G4ParticleDefinition* part = aSecTrack->GetParticle()->GetParticleDefinition();
    G4double Q = part->GetPDGCharge()/eplus;
    G4double BN = part->GetBaryonNumber();
    if (bufferA < BN) {
      bufferA = BN;
      bufferZ = Q;
    }
    Z -= Q;
    A -= BN;
  }
 
  // if the fragment was part of the final state, it is 
  // assumed to be the heaviest secondary.
  if (A < 0.1) {
    A = bufferA;
    Z = bufferZ;
  }
 
  // Prepare the IsoResult
  std::ostringstream ost1;
  ost1 << Z << "_" << A;
  G4String biff = ost1.str();
  G4IsoResult* theResult = new G4IsoResult(biff, aNucleus);
 
  return theResult;
}
 
const std::pair<G4double, G4double> G4InelasticInteraction::GetFatalEnergyCheckLevels() const
{
    // max energy non-conservation is mass of heavy nucleus
    return std::pair<G4double, G4double>(5*perCent,250*GeV);
}