Gabriele Cosmo
544 lines
21 KiB
C++
544 lines
21 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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// $Id: G4HEProtonInelastic.cc,v 1.8 2002/12/12 19:18:02 gunter Exp $
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// GEANT4 tag $Name: geant4-05-00 $
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//
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//
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#include "globals.hh"
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#include "G4ios.hh"
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//
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// G4 Process: Gheisha High Energy Collision model.
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// This includes the high energy cascading model, the two-body-resonance model
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// and the low energy two-body model. Not included are the low energy stuff like
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// nuclear reactions, nuclear fission without any cascading and all processes for
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// particles at rest.
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// First work done by J.L.Chuma and F.W.Jones, TRIUMF, June 96.
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// H. Fesefeldt, RWTH-Aachen, 23-October-1996
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// Last modified: 29-July-1998.
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#include "G4HEProtonInelastic.hh"
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G4VParticleChange * G4HEProtonInelastic::
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ApplyYourself( const G4Track &aTrack, G4Nucleus &targetNucleus )
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{
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G4HEVector * pv = new G4HEVector[MAXPART];
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theParticleChange.Initialize( aTrack );
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const G4DynamicParticle *aParticle = aTrack.GetDynamicParticle();
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// G4DynamicParticle *originalTarget = targetNucleus.ReturnTargetParticle();
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const G4double A = targetNucleus.GetN();
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const G4double Z = targetNucleus.GetZ();
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G4HEVector incidentParticle(aParticle);
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G4double atomicNumber = Z;
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G4double atomicWeight = A;
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if(verboseLevel > 1)
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G4cout << "Z , A = " << atomicNumber << " " << atomicWeight << G4endl;
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G4int incidentCode = incidentParticle.getCode();
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G4double incidentMass = incidentParticle.getMass();
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G4double incidentTotalEnergy = incidentParticle.getEnergy();
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G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
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G4double incidentKineticEnergy = incidentParticle.getKineticEnergy();
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if(incidentKineticEnergy < 1.)
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{
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G4cout << "GHEProtonInelastic: incident energy < 1 GeV" << G4endl;
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}
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if(verboseLevel > 1)
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{
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G4cout << "G4HEProtonInelastic::ApplyYourself" << G4endl;
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G4cout << "incident particle " << incidentParticle.getName() << " "
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<< "mass " << incidentMass << " "
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<< "kinetic energy " << incidentKineticEnergy
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<< G4endl;
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G4cout << "target material with (A,Z) = ("
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<< atomicWeight << "," << atomicNumber << ")" << G4endl;
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}
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G4double inelasticity = NuclearInelasticity(incidentKineticEnergy,
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atomicWeight, atomicNumber);
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if(verboseLevel > 1)
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G4cout << "nuclear inelasticity = " << inelasticity << G4endl;
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incidentKineticEnergy -= inelasticity;
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G4double excitationEnergyGNP = 0.;
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G4double excitationEnergyDTA = 0.;
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G4double excitation = NuclearExcitation(incidentKineticEnergy,
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atomicWeight, atomicNumber,
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excitationEnergyGNP,
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excitationEnergyDTA);
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if(verboseLevel > 1)
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G4cout << "nuclear excitation = " << excitation << " " << excitationEnergyGNP << " "
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<< excitationEnergyDTA << G4endl;
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incidentKineticEnergy -= excitation;
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incidentTotalEnergy = incidentKineticEnergy + incidentMass;
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incidentTotalMomentum = sqrt( (incidentTotalEnergy-incidentMass)
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*(incidentTotalEnergy+incidentMass));
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G4HEVector targetParticle;
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if(G4UniformRand() < atomicNumber/atomicWeight)
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{
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targetParticle.setDefinition("Proton");
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}
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else
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{
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targetParticle.setDefinition("Neutron");
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}
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G4double targetMass = targetParticle.getMass();
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G4double centerOfMassEnergy = sqrt( incidentMass*incidentMass + targetMass*targetMass
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+ 2.0*targetMass*incidentTotalEnergy);
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G4double availableEnergy = centerOfMassEnergy - targetMass - incidentMass;
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// this was the meaning of inElastic in the
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// original Gheisha stand-alone version.
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// G4bool inElastic = InElasticCrossSectionInFirstInt
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// (availableEnergy, incidentCode, incidentTotalMomentum);
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// by unknown reasons, it has been replaced
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// to the following code in Geant???
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G4bool inElastic = true;
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// if (G4UniformRand() < elasticCrossSection/totalCrossSection) inElastic = false;
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vecLength = 0;
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if(verboseLevel > 1)
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G4cout << "ApplyYourself: CallFirstIntInCascade for particle "
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<< incidentCode << G4endl;
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G4bool successful = false;
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if(inElastic || (!inElastic && atomicWeight < 1.5))
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{
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FirstIntInCasProton(inElastic, availableEnergy, pv, vecLength,
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incidentParticle, targetParticle, atomicWeight);
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if(verboseLevel > 1)
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G4cout << "ApplyYourself::StrangeParticlePairProduction" << G4endl;
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if ((vecLength > 0) && (availableEnergy > 1.))
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StrangeParticlePairProduction( availableEnergy, centerOfMassEnergy,
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pv, vecLength,
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incidentParticle, targetParticle);
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HighEnergyCascading( successful, pv, vecLength,
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excitationEnergyGNP, excitationEnergyDTA,
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incidentParticle, targetParticle,
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atomicWeight, atomicNumber);
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if (!successful)
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HighEnergyClusterProduction( successful, pv, vecLength,
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excitationEnergyGNP, excitationEnergyDTA,
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incidentParticle, targetParticle,
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atomicWeight, atomicNumber);
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if (!successful)
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MediumEnergyCascading( successful, pv, vecLength,
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excitationEnergyGNP, excitationEnergyDTA,
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incidentParticle, targetParticle,
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atomicWeight, atomicNumber);
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if (!successful)
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MediumEnergyClusterProduction( successful, pv, vecLength,
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excitationEnergyGNP, excitationEnergyDTA,
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incidentParticle, targetParticle,
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atomicWeight, atomicNumber);
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if (!successful)
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QuasiElasticScattering( successful, pv, vecLength,
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excitationEnergyGNP, excitationEnergyDTA,
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incidentParticle, targetParticle,
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atomicWeight, atomicNumber);
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}
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if (!successful)
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{
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ElasticScattering( successful, pv, vecLength,
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incidentParticle,
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atomicWeight, atomicNumber);
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}
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if (!successful)
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{
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G4cout << "GHEInelasticInteraction::ApplyYourself fails to produce final state particles" << G4endl;
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}
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FillParticleChange(pv, vecLength);
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delete [] pv;
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theParticleChange.SetStatusChange(fStopAndKill);
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return & theParticleChange;
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}
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void
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G4HEProtonInelastic::FirstIntInCasProton( G4bool &inElastic,
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const G4double availableEnergy,
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G4HEVector pv[],
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G4int &vecLen,
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G4HEVector incidentParticle,
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G4HEVector targetParticle,
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const G4double atomicWeight)
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// Proton undergoes interaction with nucleon within a nucleus. Check if it is
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// energetically possible to produce pions/kaons. In not, assume nuclear excitation
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// occurs and input particle is degraded in energy. No other particles are produced.
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// If reaction is possible, find the correct number of pions/protons/neutrons
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// produced using an interpolation to multiplicity data. Replace some pions or
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// protons/neutrons by kaons or strange baryons according to the average
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// multiplicity per inelastic reaction.
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{
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static const G4double expxu = log(MAXFLOAT); // upper bound for arg. of exp
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static const G4double expxl = -expxu; // lower bound for arg. of exp
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static const G4double protb = 0.7;
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static const G4double neutb = 0.35;
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static const G4double c = 1.25;
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static const G4int numMul = 1200;
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static const G4int numSec = 60;
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G4int neutronCode = Neutron.getCode();
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G4int protonCode = Proton.getCode();
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G4double pionMass = PionPlus.getMass();
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G4int targetCode = targetParticle.getCode();
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// G4double incidentMass = incidentParticle.getMass();
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// G4double incidentEnergy = incidentParticle.getEnergy();
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G4double incidentTotalMomentum = incidentParticle.getTotalMomentum();
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static G4bool first = true;
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static G4double protmul[numMul], protnorm[numSec]; // proton constants
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static G4double neutmul[numMul], neutnorm[numSec]; // neutron constants
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// misc. local variables
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// np = number of pi+, nm = number of pi-, nz = number of pi0
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G4int i, counter, nt, np, nm, nz;
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if( first )
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{ // compute normalization constants, this will only be done once
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first = false;
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for( i=0; i<numMul; i++ )protmul[i] = 0.0;
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for( i=0; i<numSec; i++ )protnorm[i] = 0.0;
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counter = -1;
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for( np=0; np<(numSec/3); np++ )
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{
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for( nm=Imax(0,np-2); nm<=np; nm++ )
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{
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for( nz=0; nz<numSec/3; nz++ )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( (nt>0) && (nt<=numSec) )
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{
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protmul[counter] = pmltpc(np,nm,nz,nt,protb,c)
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/(Factorial(2-np+nm)*Factorial(np-nm)) ;
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protnorm[nt-1] += protmul[counter];
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}
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}
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}
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}
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}
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for( i=0; i<numMul; i++ )neutmul[i] = 0.0;
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for( i=0; i<numSec; i++ )neutnorm[i] = 0.0;
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counter = -1;
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for( np=0; np<numSec/3; np++ )
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{
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for( nm=Imax(0,np-1); nm<=(np+1); nm++ )
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{
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for( nz=0; nz<numSec/3; nz++ )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( (nt>0) && (nt<=numSec) )
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{
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neutmul[counter] = pmltpc(np,nm,nz,nt,neutb,c)
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/(Factorial(1-np+nm)*Factorial(1+np-nm));
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neutnorm[nt-1] += neutmul[counter];
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}
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}
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}
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}
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}
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for( i=0; i<numSec; i++ )
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{
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if( protnorm[i] > 0.0 )protnorm[i] = 1.0/protnorm[i];
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if( neutnorm[i] > 0.0 )neutnorm[i] = 1.0/neutnorm[i];
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}
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} // end of initialization
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// initialize the first two places
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// the same as beam and target
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pv[0] = incidentParticle;
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pv[1] = targetParticle;
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vecLen = 2;
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if( !inElastic )
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{ // quasi-elastic scattering, no pions produced
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if( targetCode == neutronCode )
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{
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G4double cech[] = {0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.06, 0.04, 0.005, 0.};
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G4int iplab = G4int( Amin( 9.0, incidentTotalMomentum*2.5 ) );
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if( G4UniformRand() < cech[iplab]/pow(atomicWeight,0.42) )
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{ // charge exchange pi+ n -> pi0 p
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pv[0] = PionZero;
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pv[1] = Proton;
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}
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}
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return;
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}
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else if (availableEnergy <= pionMass)
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return;
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// inelastic scattering
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np = 0, nm = 0, nz = 0;
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G4double eab = availableEnergy;
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G4int ieab = G4int( eab*5.0 );
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G4double supp[] = {0., 0.4, 0.55, 0.65, 0.75, 0.82, 0.86, 0.90, 0.94, 0.98};
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if( (ieab <= 9) && (G4UniformRand() >= supp[ieab]) )
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{
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// suppress high multiplicity events at low momentum
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// only one additional pion will be produced
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G4double w0, wp, wm, wt, ran;
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if( targetCode == protonCode ) // target is a proton
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{
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w0 = - sqr(1.+protb)/(2.*c*c);
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wp = w0 = exp(w0);
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if( G4UniformRand() < w0/(w0+wp) )
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{ np = 0; nm = 0; nz = 1; }
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else
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{ np = 1; nm = 0; nz = 0; }
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}
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else
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{ // target is a neutron
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w0 = -sqr(1.+neutb)/(2.*c*c);
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w0 = exp(w0);
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wp = w0/2.;
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wm = -sqr(-1.+neutb)/(2.*c*c);
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wm = exp(wm)/2.;
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wt = w0+wp+wm;
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wp = w0+wp;
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ran = G4UniformRand();
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if( ran < w0/wt)
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{ np = 0; nm = 0; nz = 1; }
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else if( ran < wp/wt)
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{ np = 1; nm = 0; nz = 0; }
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else
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{ np = 0; nm = 1; nz = 0; }
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}
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}
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else
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{
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// number of total particles vs. centre of mass Energy - 2*proton mass
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G4double aleab = log(availableEnergy);
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G4double n = 3.62567+aleab*(0.665843+aleab*(0.336514
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+ aleab*(0.117712+0.0136912*aleab))) - 2.0;
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// normalization constant for kno-distribution.
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// calculate first the sum of all constants, check for numerical problems.
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G4double test, dum, anpn = 0.0;
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for( nt=1; nt<=numSec; nt++ )
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{
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test = exp( Amin( expxu, Amax( expxl, -(M_PI/4.0)*(nt*nt)/(n*n) ) ) );
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dum = M_PI*nt/(2.0*n*n);
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if( fabs(dum) < 1.0 )
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if( test >= 1.0e-10 )anpn += dum*test;
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else
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anpn += dum*test;
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}
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G4double ran = G4UniformRand();
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G4double excs = 0.0;
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if( targetCode == protonCode )
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{
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counter = -1;
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for( np=0; np<numSec/3; np++ )
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{
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for( nm=Imax(0,np-2); nm<=np; nm++ )
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{
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for( nz=0; nz<numSec/3; nz++ )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( (nt>0) && (nt<=numSec) )
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{
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test = exp( Amin( expxu, Amax( expxl, -(M_PI/4.0)*(nt*nt)/(n*n) ) ) );
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dum = (M_PI/anpn)*nt*protmul[counter]*protnorm[nt-1]/(2.0*n*n);
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if( fabs(dum) < 1.0 )
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if( test >= 1.0e-10 )excs += dum*test;
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else
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excs += dum*test;
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if (ran < excs) goto outOfLoop; //----------------------->
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}
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}
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}
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}
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}
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// 3 previous loops continued to the end
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inElastic = false; // quasi-elastic scattering
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return;
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}
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else
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{ // target must be a neutron
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counter = -1;
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for( np=0; np<numSec/3; np++ )
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{
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for( nm=Imax(0,np-1); nm<=(np+1); nm++ )
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{
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for( nz=0; nz<numSec/3; nz++ )
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{
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if( ++counter < numMul )
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{
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nt = np+nm+nz;
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if( (nt>=1) && (nt<=numSec) )
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{
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test = exp( Amin( expxu, Amax( expxl, -(M_PI/4.0)*(nt*nt)/(n*n) ) ) );
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dum = (M_PI/anpn)*nt*neutmul[counter]*neutnorm[nt-1]/(2.0*n*n);
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if( fabs(dum) < 1.0 )
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if( test >= 1.0e-10 )excs += dum*test;
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else
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excs += dum*test;
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if (ran < excs) goto outOfLoop; // -------------------------->
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}
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}
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}
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}
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}
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// 3 previous loops continued to the end
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inElastic = false; // quasi-elastic scattering.
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return;
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}
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}
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outOfLoop: // <------------------------------------------------------------------------
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if( targetCode == protonCode)
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{
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if( np == nm)
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{
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}
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else if (np == (1+nm))
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{
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if( G4UniformRand() < 0.5)
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{
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pv[1] = Neutron;
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}
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else
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{
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pv[0] = Neutron;
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}
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}
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else
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{
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pv[0] = Neutron;
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pv[1] = Neutron;
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}
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}
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else
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{
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if( np == nm)
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{
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if( G4UniformRand() < 0.25)
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{
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pv[0] = Neutron;
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pv[1] = Proton;
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}
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else
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{
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}
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}
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else if ( np == (1+nm))
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{
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pv[0] = Neutron;
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}
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else
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{
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pv[1] = Proton;
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}
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}
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nt = np + nm + nz;
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while ( nt > 0)
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{
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G4double ran = G4UniformRand();
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if ( ran < (G4double)np/nt)
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{
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if( np > 0 )
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{ pv[vecLen++] = PionPlus;
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|
np--;
|
|
}
|
|
}
|
|
else if ( ran < (G4double)(np+nm)/nt)
|
|
{
|
|
if( nm > 0 )
|
|
{
|
|
pv[vecLen++] = PionMinus;
|
|
nm--;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
if( nz > 0 )
|
|
{
|
|
pv[vecLen++] = PionZero;
|
|
nz--;
|
|
}
|
|
}
|
|
nt = np + nm + nz;
|
|
}
|
|
if (verboseLevel > 1)
|
|
{
|
|
G4cout << "Particles produced: " ;
|
|
G4cout << pv[0].getName() << " " ;
|
|
G4cout << pv[1].getName() << " " ;
|
|
for (i=2; i < vecLen; i++)
|
|
{
|
|
G4cout << pv[i].getName() << " " ;
|
|
}
|
|
G4cout << G4endl;
|
|
}
|
|
return;
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|