| 1 | //
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| 2 | // ********************************************************************
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| 3 | // * License and Disclaimer *
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| 4 | // * *
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of *
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and *
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| 7 | // * conditions of the Geant4 Software License, included in the file *
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These *
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| 9 | // * include a list of copyright holders. *
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| 10 | // * *
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| 11 | // * Neither the authors of this software system, nor their employing *
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| 12 | // * institutes,nor the agencies providing financial support for this *
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| 13 | // * work make any representation or warranty, express or implied, *
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| 14 | // * regarding this software system or assume any liability for its *
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| 15 | // * use. Please see the license in the file LICENSE and URL above *
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| 16 | // * for the full disclaimer and the limitation of liability. *
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| 17 | // * *
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| 18 | // * This code implementation is the result of the scientific and *
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| 19 | // * technical work of the GEANT4 collaboration. *
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| 20 | // * By using, copying, modifying or distributing the software (or *
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| 21 | // * any work based on the software) you agree to acknowledge its *
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| 22 | // * use in resulting scientific publications, and indicate your *
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| 23 | // * acceptance of all terms of the Geant4 Software license. *
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| 24 | // ********************************************************************
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| 25 | //
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| 26 | // $Id: G4RPGTwoBody.cc,v 1.2 2007/08/15 20:38:37 dennis Exp $
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| 27 | // GEANT4 tag $Name: geant4-09-01-patch-02 $
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| 28 | //
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| 29 |
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| 30 | #include "G4RPGTwoBody.hh"
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| 31 | #include "Randomize.hh"
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| 32 | #include "G4Poisson.hh"
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| 33 | #include <iostream>
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| 34 | #include "G4HadReentrentException.hh"
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| 35 | #include <signal.h>
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| 36 |
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| 37 |
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| 38 | G4RPGTwoBody::G4RPGTwoBody()
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| 39 | : G4RPGReaction() {}
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| 40 |
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| 41 |
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| 42 | G4bool G4RPGTwoBody::
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| 43 | ReactionStage(const G4HadProjectile* /*originalIncident*/,
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| 44 | G4ReactionProduct& modifiedOriginal,
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| 45 | G4bool& /*incidentHasChanged*/,
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| 46 | const G4DynamicParticle* originalTarget,
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| 47 | G4ReactionProduct& targetParticle,
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| 48 | G4bool& /*targetHasChanged*/,
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| 49 | const G4Nucleus& targetNucleus,
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| 50 | G4ReactionProduct& currentParticle,
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| 51 | G4FastVector<G4ReactionProduct,256>& vec,
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| 52 | G4int& vecLen,
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| 53 | G4bool /*leadFlag*/,
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| 54 | G4ReactionProduct& /*leadingStrangeParticle*/)
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| 55 | {
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| 56 | //
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| 57 | // Derived from H. Fesefeldt's original FORTRAN code TWOB
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| 58 | //
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| 59 | // Generation of momenta for elastic and quasi-elastic 2 body reactions
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| 60 | //
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| 61 | // The simple formula ds/d|t| = s0* std::exp(-b*|t|) is used.
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| 62 | // The b values are parametrizations from experimental data.
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| 63 | // Unavailable values are taken from those of similar reactions.
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| 64 | //
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| 65 |
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| 66 | const G4double ekOriginal = modifiedOriginal.GetKineticEnergy()/GeV;
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| 67 | const G4double etOriginal = modifiedOriginal.GetTotalEnergy()/GeV;
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| 68 | const G4double mOriginal = modifiedOriginal.GetMass()/GeV;
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| 69 | const G4double pOriginal = modifiedOriginal.GetMomentum().mag()/GeV;
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| 70 | G4double currentMass = currentParticle.GetMass()/GeV;
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| 71 | G4double targetMass = targetParticle.GetDefinition()->GetPDGMass()/GeV;
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| 72 |
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| 73 | targetMass = targetParticle.GetMass()/GeV;
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| 74 | const G4double atomicWeight = targetNucleus.GetN();
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| 75 |
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| 76 | G4double etCurrent = currentParticle.GetTotalEnergy()/GeV;
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| 77 | G4double pCurrent = currentParticle.GetTotalMomentum()/GeV;
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| 78 |
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| 79 | G4double cmEnergy = std::sqrt( currentMass*currentMass +
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| 80 | targetMass*targetMass +
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| 81 | 2.0*targetMass*etCurrent ); // in GeV
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| 82 |
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| 83 | if( (pCurrent < 0.1) || (cmEnergy < 0.01) ) // 2-body scattering not possible
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| 84 | {
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| 85 | targetParticle.SetMass( 0.0 ); // flag that the target particle doesn't exist
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| 86 | }
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| 87 | else
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| 88 | {
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| 89 | // Projectile momentum in cm
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| 90 |
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| 91 | G4double pf = targetMass*pCurrent/cmEnergy;
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| 92 |
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| 93 | //
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| 94 | // Set beam and target in centre of mass system
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| 95 | //
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| 96 | G4ReactionProduct pseudoParticle[3];
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| 97 |
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| 98 | if (targetParticle.GetDefinition()->GetParticleSubType() == "kaon" ||
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| 99 | targetParticle.GetDefinition()->GetParticleSubType() == "pi") {
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| 100 |
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| 101 | // G4double pf1 = pOriginal*mOriginal/std::sqrt(2.*mOriginal*(mOriginal+etOriginal));
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| 102 |
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| 103 | pseudoParticle[0].SetMass( targetMass*GeV );
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| 104 | pseudoParticle[0].SetTotalEnergy( etOriginal*GeV );
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| 105 | pseudoParticle[0].SetMomentum( 0.0, 0.0, pOriginal*GeV );
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| 106 |
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| 107 | pseudoParticle[1].SetMomentum( 0.0, 0.0, 0.0 );
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| 108 | pseudoParticle[1].SetMass( mOriginal*GeV );
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| 109 | pseudoParticle[1].SetKineticEnergy( 0.0 );
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| 110 |
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| 111 | } else {
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| 112 | pseudoParticle[0].SetMass( currentMass*GeV );
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| 113 | pseudoParticle[0].SetTotalEnergy( etCurrent*GeV );
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| 114 | pseudoParticle[0].SetMomentum( 0.0, 0.0, pCurrent*GeV );
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| 115 |
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| 116 | pseudoParticle[1].SetMomentum( 0.0, 0.0, 0.0 );
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| 117 | pseudoParticle[1].SetMass( targetMass*GeV );
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| 118 | pseudoParticle[1].SetKineticEnergy( 0.0 );
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| 119 | }
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| 120 | //
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| 121 | // Transform into center of mass system
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| 122 | //
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| 123 | pseudoParticle[2] = pseudoParticle[0] + pseudoParticle[1];
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| 124 | pseudoParticle[0].Lorentz( pseudoParticle[0], pseudoParticle[2] );
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| 125 | pseudoParticle[1].Lorentz( pseudoParticle[1], pseudoParticle[2] );
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| 126 | //
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| 127 | // Set final state masses and energies in centre of mass system
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| 128 | //
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| 129 | currentParticle.SetTotalEnergy( std::sqrt(pf*pf+currentMass*currentMass)*GeV );
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| 130 | targetParticle.SetTotalEnergy( std::sqrt(pf*pf+targetMass*targetMass)*GeV );
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| 131 |
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| 132 | //
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| 133 | // Calculate slope b for elastic scattering on proton/neutron
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| 134 | //
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| 135 | const G4double cb = 0.01;
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| 136 | const G4double b1 = 4.225;
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| 137 | const G4double b2 = 1.795;
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| 138 | G4double b = std::max( cb, b1+b2*std::log(pOriginal) );
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| 139 |
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| 140 | //
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| 141 | // Get cm scattering angle by sampling t from tmin to tmax
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| 142 | //
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| 143 | G4double btrang = b * 4.0 * pf * pseudoParticle[0].GetMomentum().mag()/GeV;
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| 144 | G4double exindt = std::exp(-btrang) - 1.0;
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| 145 | G4double costheta = 1.0 + 2*std::log( 1.0+G4UniformRand()*exindt ) /btrang;
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| 146 | costheta = std::max(-1., std::min(1., costheta) );
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| 147 | G4double sintheta = std::sqrt((1.0-costheta)*(1.0+costheta));
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| 148 | G4double phi = twopi * G4UniformRand();
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| 149 |
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| 150 | //
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| 151 | // Calculate final state momenta in centre of mass system
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| 152 | //
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| 153 | if (targetParticle.GetDefinition()->GetParticleSubType() == "kaon" ||
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| 154 | targetParticle.GetDefinition()->GetParticleSubType() == "pi") {
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| 155 |
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| 156 | currentParticle.SetMomentum( -pf*sintheta*std::cos(phi)*GeV,
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| 157 | -pf*sintheta*std::sin(phi)*GeV,
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| 158 | -pf*costheta*GeV );
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| 159 | } else {
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| 160 |
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| 161 | currentParticle.SetMomentum( pf*sintheta*std::cos(phi)*GeV,
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| 162 | pf*sintheta*std::sin(phi)*GeV,
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| 163 | pf*costheta*GeV );
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| 164 | }
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| 165 | targetParticle.SetMomentum( -currentParticle.GetMomentum() );
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| 166 |
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| 167 | //
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| 168 | // Transform into lab system
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| 169 | //
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| 170 | currentParticle.Lorentz( currentParticle, pseudoParticle[1] );
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| 171 | targetParticle.Lorentz( targetParticle, pseudoParticle[1] );
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| 172 |
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| 173 | // Rotate final state particle vectors wrt incident momentum
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| 174 |
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| 175 | Defs1( modifiedOriginal, currentParticle, targetParticle, vec, vecLen );
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| 176 |
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| 177 | // Subtract binding energy
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| 178 |
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| 179 | G4double pp, pp1, ekin;
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| 180 | if( atomicWeight >= 1.5 )
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| 181 | {
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| 182 | const G4double cfa = 0.025*((atomicWeight-1.)/120.)*std::exp(-(atomicWeight-1.)/120.);
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| 183 | pp1 = currentParticle.GetMomentum().mag()/MeV;
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| 184 | if( pp1 >= 1.0 )
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| 185 | {
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| 186 | ekin = currentParticle.GetKineticEnergy()/MeV - cfa*(1.0+0.5*normal())*GeV;
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| 187 | ekin = std::max( 0.0001*GeV, ekin );
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| 188 | currentParticle.SetKineticEnergy( ekin*MeV );
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| 189 | pp = currentParticle.GetTotalMomentum()/MeV;
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| 190 | currentParticle.SetMomentum( currentParticle.GetMomentum() * (pp/pp1) );
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| 191 | }
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| 192 | pp1 = targetParticle.GetMomentum().mag()/MeV;
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| 193 | if( pp1 >= 1.0 )
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| 194 | {
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| 195 | ekin = targetParticle.GetKineticEnergy()/MeV - cfa*(1.0+normal()/2.)*GeV;
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| 196 | ekin = std::max( 0.0001*GeV, ekin );
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| 197 | targetParticle.SetKineticEnergy( ekin*MeV );
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| 198 | pp = targetParticle.GetTotalMomentum()/MeV;
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| 199 | targetParticle.SetMomentum( targetParticle.GetMomentum() * (pp/pp1) );
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| 200 | }
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| 201 | }
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| 202 | }
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| 203 |
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| 204 | // Get number of final state nucleons and nucleons remaining in
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| 205 | // target nucleus
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| 206 |
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| 207 | std::pair<G4int, G4int> finalStateNucleons =
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| 208 | GetFinalStateNucleons(originalTarget, vec, vecLen);
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| 209 | G4int protonsInFinalState = finalStateNucleons.first;
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| 210 | G4int neutronsInFinalState = finalStateNucleons.second;
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| 211 |
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| 212 | G4int PinNucleus = std::max(0,
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| 213 | G4int(targetNucleus.GetZ()) - protonsInFinalState);
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| 214 | G4int NinNucleus = std::max(0,
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| 215 | G4int(targetNucleus.GetN()-targetNucleus.GetZ()) - neutronsInFinalState);
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| 216 |
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| 217 | if( atomicWeight >= 1.5 )
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| 218 | {
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| 219 | // Add black track particles
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| 220 | // npnb: number of proton/neutron black track particles
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| 221 | // ndta: number of deuterons, tritons, and alphas produced
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| 222 | // epnb: kinetic energy available for proton/neutron black track
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| 223 | // particles
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| 224 | // edta: kinetic energy available for deuteron/triton/alpha particles
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| 225 |
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| 226 | G4double epnb, edta;
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| 227 | G4int npnb=0, ndta=0;
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| 228 |
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| 229 | epnb = targetNucleus.GetPNBlackTrackEnergy(); // was enp1 in fortran code
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| 230 | edta = targetNucleus.GetDTABlackTrackEnergy(); // was enp3 in fortran code
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| 231 | const G4double pnCutOff = 0.0001; // GeV
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| 232 | const G4double dtaCutOff = 0.0001; // GeV
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| 233 | const G4double kineticMinimum = 0.0001;
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| 234 | const G4double kineticFactor = -0.010;
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| 235 | G4double sprob = 0.0; // sprob = probability of self-absorption in heavy molecules
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| 236 | if( epnb >= pnCutOff )
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| 237 | {
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| 238 | npnb = G4Poisson( epnb/0.02 );
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| 239 | if( npnb > atomicWeight )npnb = G4int(atomicWeight);
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| 240 | if( (epnb > pnCutOff) && (npnb <= 0) )npnb = 1;
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| 241 | npnb = std::min( npnb, 127-vecLen );
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| 242 | }
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| 243 | if( edta >= dtaCutOff )
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| 244 | {
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| 245 | ndta = G4int(2.0 * std::log(atomicWeight));
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| 246 | ndta = std::min( ndta, 127-vecLen );
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| 247 | }
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| 248 |
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| 249 | if (npnb == 0 && ndta == 0) npnb = 1;
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| 250 |
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| 251 | AddBlackTrackParticles(epnb, npnb, edta, ndta, sprob, kineticMinimum,
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| 252 | kineticFactor, modifiedOriginal,
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| 253 | PinNucleus, NinNucleus, targetNucleus,
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| 254 | vec, vecLen);
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| 255 | }
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| 256 |
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| 257 | //
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| 258 | // calculate time delay for nuclear reactions
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| 259 | //
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| 260 | if( (atomicWeight >= 1.5) && (atomicWeight <= 230.0) && (ekOriginal <= 0.2) )
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| 261 | currentParticle.SetTOF( 1.0-500.0*std::exp(-ekOriginal/0.04)*std::log(G4UniformRand()) );
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| 262 | else
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| 263 | currentParticle.SetTOF( 1.0 );
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| 264 |
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| 265 | return true;
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| 266 | }
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| 267 |
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| 268 | /* end of file */
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