[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 | // * * |
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| 21 | // * Parts of this code which have been developed by QinetiQ Ltd * |
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| 22 | // * under contract to the European Space Agency (ESA) are the * |
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| 23 | // * intellectual property of ESA. Rights to use, copy, modify and * |
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| 24 | // * redistribute this software for general public use are granted * |
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| 25 | // * in compliance with any licensing, distribution and development * |
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| 26 | // * policy adopted by the Geant4 Collaboration. This code has been * |
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| 27 | // * written by QinetiQ Ltd for the European Space Agency, under ESA * |
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| 28 | // * contract 17191/03/NL/LvH (Aurora Programme). * |
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| 29 | // * * |
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| 30 | // * By using, copying, modifying or distributing the software (or * |
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| 31 | // * any work based on the software) you agree to acknowledge its * |
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| 32 | // * use in resulting scientific publications, and indicate your * |
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| 33 | // * acceptance of all terms of the Geant4 Software license. * |
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| 34 | // ******************************************************************** |
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| 35 | // |
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| 36 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 37 | // |
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| 38 | // MODULE: G4EMDissociationCrossSection.cc |
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| 39 | // |
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| 40 | // Version: B.1 |
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| 41 | // Date: 15/04/04 |
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| 42 | // Author: P R Truscott |
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| 43 | // Organisation: QinetiQ Ltd, UK |
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| 44 | // Customer: ESA/ESTEC, NOORDWIJK |
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| 45 | // Contract: 17191/03/NL/LvH |
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| 46 | // |
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| 47 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 48 | // |
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| 49 | // CHANGE HISTORY |
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| 50 | // -------------- |
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| 51 | // |
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| 52 | // 17 October 2003, P R Truscott, QinetiQ Ltd, UK |
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| 53 | // Created. |
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| 54 | // |
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| 55 | // 15 March 2004, P R Truscott, QinetiQ Ltd, UK |
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| 56 | // Beta release |
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| 57 | // |
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| 58 | // 30. May 2005, J.P. Wellisch removed a compilation warning on gcc 3.4 for gant4 7.1. |
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| 59 | // |
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| 60 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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| 61 | //////////////////////////////////////////////////////////////////////////////// |
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| 62 | // |
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| 63 | #include "G4EMDissociationCrossSection.hh" |
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| 64 | #include "G4PhysicsFreeVector.hh" |
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| 65 | #include "G4ParticleTable.hh" |
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| 66 | #include "G4IonTable.hh" |
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| 67 | #include "globals.hh" |
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| 68 | //////////////////////////////////////////////////////////////////////////////// |
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| 69 | // |
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| 70 | G4EMDissociationCrossSection::G4EMDissociationCrossSection () |
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| 71 | { |
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| 72 | // |
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| 73 | // |
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| 74 | // This function makes use of the class which can sample the virtual photon |
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| 75 | // spectrum, G4EMDissociationSpectrum. |
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| 76 | // |
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| 77 | thePhotonSpectrum = new G4EMDissociationSpectrum(); |
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| 78 | // |
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| 79 | // |
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| 80 | // Define other constants. |
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| 81 | // |
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| 82 | r0 = 1.18 * fermi; |
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| 83 | J = 36.8 * MeV; |
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| 84 | Qprime = 17.0 * MeV; |
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| 85 | epsilon = 0.0768; |
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| 86 | xd = 0.25; |
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| 87 | } |
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| 88 | //////////////////////////////////////////////////////////////////////////////// |
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| 89 | // |
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| 90 | G4EMDissociationCrossSection::~G4EMDissociationCrossSection() |
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| 91 | { |
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| 92 | delete thePhotonSpectrum; |
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| 93 | } |
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| 94 | /////////////////////////////////////////////////////////////////////////////// |
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| 95 | // |
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| 96 | G4bool G4EMDissociationCrossSection::IsZAApplicable |
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| 97 | (const G4DynamicParticle* theDynamicParticle, G4double /*ZZ*/, G4double AA) |
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| 98 | { |
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| 99 | // |
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| 100 | // The condition for the applicability of this class is that the projectile |
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| 101 | // must be an ion and the target must have more than one nucleon. In reality |
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| 102 | // the value of A for either the projectile or target could be much higher, |
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| 103 | // since for cases where both he projectile and target are medium to small |
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| 104 | // Z, the probability of the EMD process is, I think, VERY small. |
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| 105 | // |
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| 106 | if (G4ParticleTable::GetParticleTable()->GetIonTable()-> |
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| 107 | IsIon(theDynamicParticle->GetDefinition()) && AA > 1.0) |
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| 108 | return true; |
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| 109 | else |
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| 110 | return false; |
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| 111 | } |
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| 112 | |
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| 113 | G4bool G4EMDissociationCrossSection::IsApplicable |
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| 114 | (const G4DynamicParticle* theDynamicParticle, const G4Element* theElement) |
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| 115 | { |
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| 116 | return IsZAApplicable(theDynamicParticle, 0., theElement->GetN()); |
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| 117 | } |
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| 118 | |
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| 119 | ////////////////////////////////////////////////////////////////////////////// |
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| 120 | // |
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| 121 | G4double G4EMDissociationCrossSection::GetCrossSection |
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| 122 | (const G4DynamicParticle* theDynamicParticle, const G4Element* theElement, |
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| 123 | G4double temperature) |
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| 124 | { |
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| 125 | G4int nIso = theElement->GetNumberOfIsotopes(); |
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| 126 | G4double crossSection = 0; |
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| 127 | |
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| 128 | if (nIso) { |
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| 129 | G4double sig; |
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| 130 | G4IsotopeVector* isoVector = theElement->GetIsotopeVector(); |
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| 131 | G4double* abundVector = theElement->GetRelativeAbundanceVector(); |
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| 132 | G4double ZZ; |
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| 133 | G4double AA; |
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| 134 | |
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| 135 | for (G4int i = 0; i < nIso; i++) { |
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| 136 | ZZ = G4double( (*isoVector)[i]->GetZ() ); |
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| 137 | AA = G4double( (*isoVector)[i]->GetN() ); |
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| 138 | sig = GetIsoZACrossSection(theDynamicParticle, ZZ, AA, temperature); |
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| 139 | crossSection += sig*abundVector[i]; |
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| 140 | } |
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| 141 | |
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| 142 | } else { |
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| 143 | crossSection = |
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| 144 | GetIsoZACrossSection(theDynamicParticle, theElement->GetZ(), |
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| 145 | theElement->GetN(), temperature); |
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| 146 | } |
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| 147 | |
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| 148 | return crossSection; |
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| 149 | } |
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| 150 | |
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| 151 | |
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| 152 | G4double G4EMDissociationCrossSection::GetIsoZACrossSection |
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| 153 | (const G4DynamicParticle *theDynamicParticle, G4double ZZ, G4double AA, |
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| 154 | G4double /*temperature*/) |
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| 155 | { |
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| 156 | // |
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| 157 | // |
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| 158 | // Get relevant information about the projectile and target (A, Z) and |
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| 159 | // velocity of the projectile. |
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| 160 | // |
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| 161 | G4ParticleDefinition *definitionP = theDynamicParticle->GetDefinition(); |
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| 162 | G4double AP = definitionP->GetBaryonNumber(); |
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| 163 | G4double ZP = definitionP->GetPDGCharge(); |
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| 164 | G4double b = theDynamicParticle->Get4Momentum().beta(); |
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| 165 | // G4double bsq = b * b; |
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| 166 | |
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| 167 | G4double AT = AA; |
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| 168 | G4double ZT = ZZ; |
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| 169 | G4double bmin = thePhotonSpectrum->GetClosestApproach(AP, ZP, AT, ZT, b); |
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| 170 | // |
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| 171 | // |
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| 172 | // Calculate the cross-section for the projectile and then the target. The |
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| 173 | // information is returned in a G4PhysicsFreeVector, which separates out the |
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| 174 | // cross-sections for the E1 and E2 moments of the virtual photon field, and |
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| 175 | // the energies (GDR and GQR). |
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| 176 | // |
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| 177 | G4PhysicsFreeVector *theProjectileCrossSections = |
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| 178 | GetCrossSectionForProjectile (AP, ZP, AT, ZT, b, bmin); |
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| 179 | G4double crossSection = |
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| 180 | (*theProjectileCrossSections)[0]+(*theProjectileCrossSections)[1]; |
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| 181 | delete theProjectileCrossSections; |
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| 182 | G4PhysicsFreeVector *theTargetCrossSections = |
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| 183 | GetCrossSectionForTarget (AP, ZP, AT, ZT, b, bmin); |
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| 184 | crossSection += |
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| 185 | (*theTargetCrossSections)[0]+(*theTargetCrossSections)[1]; |
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| 186 | delete theTargetCrossSections; |
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| 187 | |
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| 188 | return crossSection; |
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| 189 | } |
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| 190 | //////////////////////////////////////////////////////////////////////////////// |
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| 191 | // |
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| 192 | G4PhysicsFreeVector * |
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| 193 | G4EMDissociationCrossSection::GetCrossSectionForProjectile (G4double AP, |
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| 194 | G4double ZP, G4double /* AT */, G4double ZT, G4double b, G4double bmin) |
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| 195 | { |
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| 196 | // |
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| 197 | // |
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| 198 | // Use Wilson et al's approach to calculate the cross-sections due to the E1 |
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| 199 | // and E2 moments of the field at the giant dipole and quadrupole resonances |
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| 200 | // respectively, Note that the algorithm is traditionally applied to the |
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| 201 | // EMD break-up of the projectile in the field of the target, as is implemented |
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| 202 | // here. |
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| 203 | // |
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| 204 | // Initialise variables and calculate the energies for the GDR and GQR. |
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| 205 | // |
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| 206 | G4double AProot3 = std::pow(AP,1.0/3.0); |
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| 207 | G4double u = 3.0 * J / Qprime / AProot3; |
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| 208 | G4double R0 = r0 * AProot3; |
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| 209 | G4double E_GDR = hbarc / std::sqrt(0.7*amu_c2*R0*R0/8.0/J* |
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| 210 | (1.0 + u - (1.0 + epsilon + 3.0*u)/(1.0 + epsilon + u)*epsilon)); |
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| 211 | G4double E_GQR = 63.0 * MeV / AProot3; |
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| 212 | // |
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| 213 | // |
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| 214 | // Determine the virtual photon spectra at these energies. |
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| 215 | // |
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| 216 | G4double ZTsq = ZT * ZT; |
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| 217 | G4double nE1 = ZTsq * |
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| 218 | thePhotonSpectrum->GetGeneralE1Spectrum(E_GDR, b, bmin); |
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| 219 | G4double nE2 = ZTsq * |
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| 220 | thePhotonSpectrum->GetGeneralE2Spectrum(E_GQR, b, bmin); |
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| 221 | // |
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| 222 | // |
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| 223 | // Now calculate the cross-section of the projectile for interaction with the |
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| 224 | // E1 and E2 fields. |
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| 225 | // |
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| 226 | G4double sE1 = 60.0 * millibarn * MeV * (AP-ZP)*ZP/AP; |
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| 227 | G4double sE2 = 0.22 * microbarn / MeV * ZP * AProot3 * AProot3; |
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| 228 | if (AP > 100.0) sE2 *= 0.9; |
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| 229 | else if (AP > 40.0) sE2 *= 0.6; |
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| 230 | else sE2 *= 0.3; |
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| 231 | // |
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| 232 | // |
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| 233 | // ... and multiply with the intensity of the virtual photon spectra to get |
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| 234 | // the probability of interaction. |
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| 235 | // |
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| 236 | G4PhysicsFreeVector *theCrossSectionVector = new G4PhysicsFreeVector(2); |
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| 237 | theCrossSectionVector->PutValue(0, E_GDR, sE1*nE1); |
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| 238 | theCrossSectionVector->PutValue(1, E_GQR, sE2*nE2*E_GQR*E_GQR); |
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| 239 | |
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| 240 | return theCrossSectionVector; |
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| 241 | } |
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| 242 | //////////////////////////////////////////////////////////////////////////////// |
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| 243 | // |
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| 244 | G4PhysicsFreeVector * |
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| 245 | G4EMDissociationCrossSection::GetCrossSectionForTarget (G4double AP, |
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| 246 | G4double ZP, G4double AT, G4double ZT, G4double b, G4double bmin) |
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| 247 | { |
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| 248 | // |
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| 249 | // |
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| 250 | // This is a cheaky little member function to calculate the probability of |
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| 251 | // EMD for the target in the field of the projectile ... just by reversing the |
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| 252 | // A and Z's for the participants. |
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| 253 | // |
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| 254 | return GetCrossSectionForProjectile (AT, ZT, AP, ZP, b, bmin); |
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| 255 | } |
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| 256 | //////////////////////////////////////////////////////////////////////////////// |
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| 257 | // |
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| 258 | G4double |
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| 259 | G4EMDissociationCrossSection::GetWilsonProbabilityForProtonDissociation |
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| 260 | (G4double A, G4double Z) |
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| 261 | { |
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| 262 | // |
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| 263 | // |
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| 264 | // This is a simple algorithm to choose whether a proton or neutron is ejected |
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| 265 | // from the nucleus in the EMD interaction. |
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| 266 | // |
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| 267 | G4double p = 0.0; |
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| 268 | if (Z < 6.0) |
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| 269 | p = 0.5; |
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| 270 | else if (Z < 8.0) |
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| 271 | p = 0.6; |
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| 272 | else if (Z < 14.0) |
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| 273 | p = 0.7; |
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| 274 | else |
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| 275 | { |
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| 276 | G4double p1 = (G4double) Z / (G4double) A; |
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| 277 | G4double p2 = 1.95*std::exp(-0.075*Z); |
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| 278 | if (p1 < p2) p = p1; |
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| 279 | else p = p2; |
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| 280 | } |
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| 281 | |
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| 282 | return p; |
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| 283 | } |
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| 284 | //////////////////////////////////////////////////////////////////////////////// |
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| 285 | // |
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