| 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
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| 59 | // geant4 7.1.
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| 60 | //
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| 61 | // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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| 62 | //////////////////////////////////////////////////////////////////////////////
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| 63 | //
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| 64 | #include "G4EMDissociationCrossSection.hh"
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| 65 | #include "G4PhysicsFreeVector.hh"
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| 66 | #include "G4ParticleTable.hh"
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| 67 | #include "G4IonTable.hh"
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| 68 | #include "G4HadTmpUtil.hh"
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| 69 | #include "globals.hh"
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| 70 |
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| 71 |
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| 72 | G4EMDissociationCrossSection::G4EMDissociationCrossSection ()
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| 73 | {
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| 74 | //
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| 75 | // This function makes use of the class which can sample the virtual photon
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| 76 | // spectrum, G4EMDissociationSpectrum.
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| 77 | //
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| 78 | thePhotonSpectrum = new G4EMDissociationSpectrum();
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| 79 | //
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| 80 | //
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| 81 | // Define other constants.
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| 82 | //
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| 83 | r0 = 1.18 * fermi;
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| 84 | J = 36.8 * MeV;
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| 85 | Qprime = 17.0 * MeV;
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| 86 | epsilon = 0.0768;
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| 87 | xd = 0.25;
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| 88 | }
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| 89 | //////////////////////////////////////////////////////////////////////////////
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| 90 | //
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| 91 | G4EMDissociationCrossSection::~G4EMDissociationCrossSection()
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| 92 | {
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| 93 | delete thePhotonSpectrum;
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| 94 | }
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| 95 | /////////////////////////////////////////////////////////////////////////////
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| 96 | //
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| 97 | G4bool
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| 98 | G4EMDissociationCrossSection::IsIsoApplicable(const G4DynamicParticle* theDynamicParticle,
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| 99 | G4int /*ZZ*/, G4int AA)
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| 100 | {
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| 101 | //
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| 102 | // The condition for the applicability of this class is that the projectile
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| 103 | // must be an ion and the target must have more than one nucleon. In reality
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| 104 | // the value of A for either the projectile or target could be much higher,
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| 105 | // since for cases where both he projectile and target are medium to small
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| 106 | // Z, the probability of the EMD process is, I think, VERY small.
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| 107 | //
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| 108 | if (G4ParticleTable::GetParticleTable()->GetIonTable()->
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| 109 | IsIon(theDynamicParticle->GetDefinition()) && AA > 1)
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| 110 | return true;
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| 111 | else
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| 112 | return false;
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| 113 | }
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| 114 |
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| 115 | G4bool G4EMDissociationCrossSection::IsApplicable
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| 116 | (const G4DynamicParticle* theDynamicParticle, const G4Element* theElement)
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| 117 | {
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| 118 | return IsIsoApplicable(theDynamicParticle, 0, G4lrint(theElement->GetN()));
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| 119 | }
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| 120 |
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| 121 | //////////////////////////////////////////////////////////////////////////////
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| 122 | //
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| 123 | G4double G4EMDissociationCrossSection::GetCrossSection
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| 124 | (const G4DynamicParticle* theDynamicParticle, const G4Element* theElement,
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| 125 | G4double temperature)
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| 126 | {
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| 127 | G4int nIso = theElement->GetNumberOfIsotopes();
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| 128 | G4double crossSection = 0;
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| 129 |
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| 130 | if (nIso) {
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| 131 | G4double sig;
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| 132 | G4IsotopeVector* isoVector = theElement->GetIsotopeVector();
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| 133 | G4double* abundVector = theElement->GetRelativeAbundanceVector();
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| 134 | G4int ZZ;
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| 135 | G4int AA;
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| 136 |
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| 137 | for (G4int i = 0; i < nIso; i++) {
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| 138 | ZZ = (*isoVector)[i]->GetZ();
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| 139 | AA = (*isoVector)[i]->GetN();
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| 140 | sig = GetZandACrossSection(theDynamicParticle, ZZ, AA, temperature);
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| 141 | crossSection += sig*abundVector[i];
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| 142 | }
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| 143 |
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| 144 | } else {
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| 145 | G4int ZZ = G4lrint(theElement->GetZ());
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| 146 | G4int AA = G4lrint(theElement->GetN());
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| 147 | crossSection = GetZandACrossSection(theDynamicParticle, ZZ, AA, temperature);
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| 148 | }
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| 149 |
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| 150 | return crossSection;
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| 151 | }
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| 152 |
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| 153 |
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| 154 | G4double
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| 155 | G4EMDissociationCrossSection::GetZandACrossSection(const G4DynamicParticle *theDynamicParticle,
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| 156 | G4int ZZ, G4int AA, G4double /*temperature*/)
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| 157 | {
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| 158 | //
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| 159 | // Get relevant information about the projectile and target (A, Z) and
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| 160 | // velocity of the projectile.
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| 161 | //
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| 162 | G4ParticleDefinition *definitionP = theDynamicParticle->GetDefinition();
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| 163 | G4double AP = definitionP->GetBaryonNumber();
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| 164 | G4double ZP = definitionP->GetPDGCharge();
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| 165 | G4double b = theDynamicParticle->Get4Momentum().beta();
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| 166 | // G4double bsq = b * b;
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| 167 |
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| 168 | G4double AT = AA;
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| 169 | G4double ZT = ZZ;
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| 170 | G4double bmin = thePhotonSpectrum->GetClosestApproach(AP, ZP, AT, ZT, b);
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| 171 | //
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| 172 | //
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| 173 | // Calculate the cross-section for the projectile and then the target. The
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| 174 | // information is returned in a G4PhysicsFreeVector, which separates out the
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| 175 | // cross-sections for the E1 and E2 moments of the virtual photon field, and
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| 176 | // the energies (GDR and GQR).
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| 177 | //
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| 178 | G4PhysicsFreeVector *theProjectileCrossSections =
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| 179 | GetCrossSectionForProjectile (AP, ZP, AT, ZT, b, bmin);
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| 180 | G4double crossSection =
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| 181 | (*theProjectileCrossSections)[0]+(*theProjectileCrossSections)[1];
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| 182 | delete theProjectileCrossSections;
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| 183 | G4PhysicsFreeVector *theTargetCrossSections =
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| 184 | GetCrossSectionForTarget (AP, ZP, AT, ZT, b, bmin);
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| 185 | crossSection +=
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| 186 | (*theTargetCrossSections)[0]+(*theTargetCrossSections)[1];
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| 187 | delete theTargetCrossSections;
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| 188 |
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| 189 | return crossSection;
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| 190 | }
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| 191 | ////////////////////////////////////////////////////////////////////////////////
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| 192 | //
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| 193 | G4PhysicsFreeVector *
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| 194 | G4EMDissociationCrossSection::GetCrossSectionForProjectile (G4double AP,
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| 195 | G4double ZP, G4double /* AT */, G4double ZT, G4double b, G4double bmin)
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| 196 | {
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| 197 | //
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| 198 | //
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| 199 | // Use Wilson et al's approach to calculate the cross-sections due to the E1
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| 200 | // and E2 moments of the field at the giant dipole and quadrupole resonances
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| 201 | // respectively, Note that the algorithm is traditionally applied to the
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| 202 | // EMD break-up of the projectile in the field of the target, as is implemented
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| 203 | // here.
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| 204 | //
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| 205 | // Initialise variables and calculate the energies for the GDR and GQR.
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| 206 | //
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| 207 | G4double AProot3 = std::pow(AP,1.0/3.0);
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| 208 | G4double u = 3.0 * J / Qprime / AProot3;
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| 209 | G4double R0 = r0 * AProot3;
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| 210 | G4double E_GDR = hbarc / std::sqrt(0.7*amu_c2*R0*R0/8.0/J*
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| 211 | (1.0 + u - (1.0 + epsilon + 3.0*u)/(1.0 + epsilon + u)*epsilon));
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| 212 | G4double E_GQR = 63.0 * MeV / AProot3;
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| 213 | //
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| 214 | //
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| 215 | // Determine the virtual photon spectra at these energies.
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| 216 | //
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| 217 | G4double ZTsq = ZT * ZT;
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| 218 | G4double nE1 = ZTsq *
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| 219 | thePhotonSpectrum->GetGeneralE1Spectrum(E_GDR, b, bmin);
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| 220 | G4double nE2 = ZTsq *
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| 221 | thePhotonSpectrum->GetGeneralE2Spectrum(E_GQR, b, bmin);
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| 222 | //
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| 223 | //
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| 224 | // Now calculate the cross-section of the projectile for interaction with the
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| 225 | // E1 and E2 fields.
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| 226 | //
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| 227 | G4double sE1 = 60.0 * millibarn * MeV * (AP-ZP)*ZP/AP;
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| 228 | G4double sE2 = 0.22 * microbarn / MeV * ZP * AProot3 * AProot3;
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| 229 | if (AP > 100.0) sE2 *= 0.9;
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| 230 | else if (AP > 40.0) sE2 *= 0.6;
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| 231 | else sE2 *= 0.3;
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| 232 | //
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| 233 | //
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| 234 | // ... and multiply with the intensity of the virtual photon spectra to get
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| 235 | // the probability of interaction.
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| 236 | //
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| 237 | G4PhysicsFreeVector *theCrossSectionVector = new G4PhysicsFreeVector(2);
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| 238 | theCrossSectionVector->PutValue(0, E_GDR, sE1*nE1);
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| 239 | theCrossSectionVector->PutValue(1, E_GQR, sE2*nE2*E_GQR*E_GQR);
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| 240 |
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| 241 | return theCrossSectionVector;
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| 242 | }
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| 243 |
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| 244 | ////////////////////////////////////////////////////////////////////////////////
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| 245 | //
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| 246 | G4PhysicsFreeVector *
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| 247 | G4EMDissociationCrossSection::GetCrossSectionForTarget (G4double AP,
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| 248 | G4double ZP, G4double AT, G4double ZT, G4double b, G4double bmin)
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| 249 | {
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| 250 | //
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| 251 | // This is a cheaky little member function to calculate the probability of
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| 252 | // EMD for the target in the field of the projectile ... just by reversing the
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| 253 | // A and Z's for the participants.
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| 254 | //
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| 255 | return GetCrossSectionForProjectile (AT, ZT, AP, ZP, b, bmin);
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| 256 | }
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| 257 |
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| 258 |
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| 259 | G4double
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| 260 | G4EMDissociationCrossSection::GetWilsonProbabilityForProtonDissociation(G4double A,
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| 261 | G4double Z)
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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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