[819] | 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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[962] | 26 | // $Id: G4RPGTwoBody.cc,v 1.4 2008/05/05 21:21:55 dennis Exp $ |
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[1228] | 27 | // GEANT4 tag $Name: geant4-09-03 $ |
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[819] | 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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[962] | 83 | if (cmEnergy < 0.01) { // 2-body scattering not possible |
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[819] | 84 | targetParticle.SetMass( 0.0 ); // flag that the target particle doesn't exist |
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[962] | 85 | |
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| 86 | } else { |
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[819] | 87 | // Projectile momentum in cm |
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| 88 | |
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| 89 | G4double pf = targetMass*pCurrent/cmEnergy; |
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| 90 | |
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| 91 | // |
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| 92 | // Set beam and target in centre of mass system |
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| 93 | // |
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| 94 | G4ReactionProduct pseudoParticle[3]; |
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| 95 | |
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| 96 | if (targetParticle.GetDefinition()->GetParticleSubType() == "kaon" || |
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| 97 | targetParticle.GetDefinition()->GetParticleSubType() == "pi") { |
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| 98 | |
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| 99 | // G4double pf1 = pOriginal*mOriginal/std::sqrt(2.*mOriginal*(mOriginal+etOriginal)); |
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| 100 | |
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| 101 | pseudoParticle[0].SetMass( targetMass*GeV ); |
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| 102 | pseudoParticle[0].SetTotalEnergy( etOriginal*GeV ); |
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| 103 | pseudoParticle[0].SetMomentum( 0.0, 0.0, pOriginal*GeV ); |
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| 104 | |
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| 105 | pseudoParticle[1].SetMomentum( 0.0, 0.0, 0.0 ); |
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| 106 | pseudoParticle[1].SetMass( mOriginal*GeV ); |
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| 107 | pseudoParticle[1].SetKineticEnergy( 0.0 ); |
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| 108 | |
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| 109 | } else { |
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| 110 | pseudoParticle[0].SetMass( currentMass*GeV ); |
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| 111 | pseudoParticle[0].SetTotalEnergy( etCurrent*GeV ); |
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| 112 | pseudoParticle[0].SetMomentum( 0.0, 0.0, pCurrent*GeV ); |
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| 113 | |
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| 114 | pseudoParticle[1].SetMomentum( 0.0, 0.0, 0.0 ); |
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| 115 | pseudoParticle[1].SetMass( targetMass*GeV ); |
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| 116 | pseudoParticle[1].SetKineticEnergy( 0.0 ); |
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| 117 | } |
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| 118 | // |
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| 119 | // Transform into center of mass system |
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| 120 | // |
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| 121 | pseudoParticle[2] = pseudoParticle[0] + pseudoParticle[1]; |
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| 122 | pseudoParticle[0].Lorentz( pseudoParticle[0], pseudoParticle[2] ); |
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| 123 | pseudoParticle[1].Lorentz( pseudoParticle[1], pseudoParticle[2] ); |
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| 124 | // |
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| 125 | // Set final state masses and energies in centre of mass system |
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| 126 | // |
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| 127 | currentParticle.SetTotalEnergy( std::sqrt(pf*pf+currentMass*currentMass)*GeV ); |
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| 128 | targetParticle.SetTotalEnergy( std::sqrt(pf*pf+targetMass*targetMass)*GeV ); |
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| 129 | |
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| 130 | // |
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| 131 | // Calculate slope b for elastic scattering on proton/neutron |
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| 132 | // |
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| 133 | const G4double cb = 0.01; |
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| 134 | const G4double b1 = 4.225; |
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| 135 | const G4double b2 = 1.795; |
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| 136 | G4double b = std::max( cb, b1+b2*std::log(pOriginal) ); |
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| 137 | |
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| 138 | // |
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| 139 | // Get cm scattering angle by sampling t from tmin to tmax |
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| 140 | // |
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| 141 | G4double btrang = b * 4.0 * pf * pseudoParticle[0].GetMomentum().mag()/GeV; |
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| 142 | G4double exindt = std::exp(-btrang) - 1.0; |
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| 143 | G4double costheta = 1.0 + 2*std::log( 1.0+G4UniformRand()*exindt ) /btrang; |
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| 144 | costheta = std::max(-1., std::min(1., costheta) ); |
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| 145 | G4double sintheta = std::sqrt((1.0-costheta)*(1.0+costheta)); |
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| 146 | G4double phi = twopi * G4UniformRand(); |
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| 147 | |
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| 148 | // |
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| 149 | // Calculate final state momenta in centre of mass system |
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| 150 | // |
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| 151 | if (targetParticle.GetDefinition()->GetParticleSubType() == "kaon" || |
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| 152 | targetParticle.GetDefinition()->GetParticleSubType() == "pi") { |
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| 153 | |
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| 154 | currentParticle.SetMomentum( -pf*sintheta*std::cos(phi)*GeV, |
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| 155 | -pf*sintheta*std::sin(phi)*GeV, |
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| 156 | -pf*costheta*GeV ); |
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| 157 | } else { |
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| 158 | |
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| 159 | currentParticle.SetMomentum( pf*sintheta*std::cos(phi)*GeV, |
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| 160 | pf*sintheta*std::sin(phi)*GeV, |
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| 161 | pf*costheta*GeV ); |
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| 162 | } |
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| 163 | targetParticle.SetMomentum( -currentParticle.GetMomentum() ); |
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| 164 | |
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| 165 | // |
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| 166 | // Transform into lab system |
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| 167 | // |
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| 168 | currentParticle.Lorentz( currentParticle, pseudoParticle[1] ); |
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| 169 | targetParticle.Lorentz( targetParticle, pseudoParticle[1] ); |
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| 170 | |
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| 171 | // Rotate final state particle vectors wrt incident momentum |
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| 172 | |
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| 173 | Defs1( modifiedOriginal, currentParticle, targetParticle, vec, vecLen ); |
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| 174 | |
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| 175 | // Subtract binding energy |
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| 176 | |
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| 177 | G4double pp, pp1, ekin; |
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| 178 | if( atomicWeight >= 1.5 ) |
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| 179 | { |
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| 180 | const G4double cfa = 0.025*((atomicWeight-1.)/120.)*std::exp(-(atomicWeight-1.)/120.); |
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| 181 | pp1 = currentParticle.GetMomentum().mag()/MeV; |
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| 182 | if( pp1 >= 1.0 ) |
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| 183 | { |
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| 184 | ekin = currentParticle.GetKineticEnergy()/MeV - cfa*(1.0+0.5*normal())*GeV; |
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| 185 | ekin = std::max( 0.0001*GeV, ekin ); |
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| 186 | currentParticle.SetKineticEnergy( ekin*MeV ); |
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| 187 | pp = currentParticle.GetTotalMomentum()/MeV; |
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| 188 | currentParticle.SetMomentum( currentParticle.GetMomentum() * (pp/pp1) ); |
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| 189 | } |
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| 190 | pp1 = targetParticle.GetMomentum().mag()/MeV; |
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| 191 | if( pp1 >= 1.0 ) |
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| 192 | { |
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| 193 | ekin = targetParticle.GetKineticEnergy()/MeV - cfa*(1.0+normal()/2.)*GeV; |
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| 194 | ekin = std::max( 0.0001*GeV, ekin ); |
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| 195 | targetParticle.SetKineticEnergy( ekin*MeV ); |
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| 196 | pp = targetParticle.GetTotalMomentum()/MeV; |
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| 197 | targetParticle.SetMomentum( targetParticle.GetMomentum() * (pp/pp1) ); |
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| 198 | } |
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| 199 | } |
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| 200 | } |
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| 201 | |
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| 202 | // Get number of final state nucleons and nucleons remaining in |
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| 203 | // target nucleus |
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| 204 | |
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| 205 | std::pair<G4int, G4int> finalStateNucleons = |
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| 206 | GetFinalStateNucleons(originalTarget, vec, vecLen); |
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| 207 | G4int protonsInFinalState = finalStateNucleons.first; |
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| 208 | G4int neutronsInFinalState = finalStateNucleons.second; |
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| 209 | |
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| 210 | G4int PinNucleus = std::max(0, |
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| 211 | G4int(targetNucleus.GetZ()) - protonsInFinalState); |
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| 212 | G4int NinNucleus = std::max(0, |
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| 213 | G4int(targetNucleus.GetN()-targetNucleus.GetZ()) - neutronsInFinalState); |
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| 214 | |
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| 215 | if( atomicWeight >= 1.5 ) |
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| 216 | { |
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| 217 | // Add black track particles |
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| 218 | // npnb: number of proton/neutron black track particles |
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| 219 | // ndta: number of deuterons, tritons, and alphas produced |
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| 220 | // epnb: kinetic energy available for proton/neutron black track |
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| 221 | // particles |
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| 222 | // edta: kinetic energy available for deuteron/triton/alpha particles |
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| 223 | |
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| 224 | G4double epnb, edta; |
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| 225 | G4int npnb=0, ndta=0; |
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| 226 | |
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| 227 | epnb = targetNucleus.GetPNBlackTrackEnergy(); // was enp1 in fortran code |
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| 228 | edta = targetNucleus.GetDTABlackTrackEnergy(); // was enp3 in fortran code |
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| 229 | const G4double pnCutOff = 0.0001; // GeV |
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| 230 | const G4double dtaCutOff = 0.0001; // GeV |
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[962] | 231 | // const G4double kineticMinimum = 0.0001; |
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| 232 | // const G4double kineticFactor = -0.010; |
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| 233 | // G4double sprob = 0.0; // sprob = probability of self-absorption in heavy molecules |
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[819] | 234 | if( epnb >= pnCutOff ) |
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| 235 | { |
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| 236 | npnb = G4Poisson( epnb/0.02 ); |
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| 237 | if( npnb > atomicWeight )npnb = G4int(atomicWeight); |
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| 238 | if( (epnb > pnCutOff) && (npnb <= 0) )npnb = 1; |
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| 239 | npnb = std::min( npnb, 127-vecLen ); |
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| 240 | } |
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| 241 | if( edta >= dtaCutOff ) |
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| 242 | { |
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| 243 | ndta = G4int(2.0 * std::log(atomicWeight)); |
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| 244 | ndta = std::min( ndta, 127-vecLen ); |
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| 245 | } |
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| 246 | |
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| 247 | if (npnb == 0 && ndta == 0) npnb = 1; |
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| 248 | |
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[962] | 249 | AddBlackTrackParticles(epnb, npnb, edta, ndta, modifiedOriginal, |
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[819] | 250 | PinNucleus, NinNucleus, targetNucleus, |
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| 251 | vec, vecLen); |
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| 252 | } |
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| 253 | |
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| 254 | // |
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| 255 | // calculate time delay for nuclear reactions |
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| 256 | // |
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| 257 | if( (atomicWeight >= 1.5) && (atomicWeight <= 230.0) && (ekOriginal <= 0.2) ) |
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| 258 | currentParticle.SetTOF( 1.0-500.0*std::exp(-ekOriginal/0.04)*std::log(G4UniformRand()) ); |
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| 259 | else |
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| 260 | currentParticle.SetTOF( 1.0 ); |
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| 261 | |
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| 262 | return true; |
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| 263 | } |
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| 264 | |
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| 265 | /* end of file */ |
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