[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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[1228] | 26 | // $Id: G4PreCompoundTransitions.cc,v 1.22 2009/11/21 18:03:13 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-03 $ |
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[819] | 28 | // |
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[1055] | 29 | // ------------------------------------------------------------------- |
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| 30 | // |
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| 31 | // GEANT4 Class file |
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| 32 | // |
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| 33 | // |
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| 34 | // File name: G4PreCompoundIon |
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| 35 | // |
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| 36 | // Author: V.Lara |
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| 37 | // |
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| 38 | // Modified: |
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| 39 | // 16.02.2008 J. M. Quesada fixed bugs |
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| 40 | // 06.09.2008 J. M. Quesada added external choices for: |
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[962] | 41 | // - "never go back" hipothesis (useNGB=true) |
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| 42 | // - CEM transition probabilities (useCEMtr=true) |
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[1055] | 43 | |
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[1196] | 44 | // 30.10.09 J.M.Quesada: CEM transition probabilities have been renormalized |
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| 45 | // (IAEA benchmark) |
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| 46 | // |
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[819] | 47 | #include "G4PreCompoundTransitions.hh" |
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| 48 | #include "G4HadronicException.hh" |
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| 49 | |
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| 50 | const G4PreCompoundTransitions & G4PreCompoundTransitions:: |
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| 51 | operator=(const G4PreCompoundTransitions &) |
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| 52 | { |
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| 53 | throw G4HadronicException(__FILE__, __LINE__, "G4PreCompoundTransitions::operator= meant to not be accessable"); |
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| 54 | return *this; |
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| 55 | } |
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| 56 | |
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| 57 | |
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| 58 | G4bool G4PreCompoundTransitions::operator==(const G4PreCompoundTransitions &) const |
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| 59 | { |
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| 60 | return false; |
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| 61 | } |
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| 62 | |
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| 63 | G4bool G4PreCompoundTransitions::operator!=(const G4PreCompoundTransitions &) const |
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| 64 | { |
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| 65 | return true; |
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| 66 | } |
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| 67 | |
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| 68 | |
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| 69 | G4double G4PreCompoundTransitions:: |
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| 70 | CalculateProbability(const G4Fragment & aFragment) |
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| 71 | { |
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[962] | 72 | //G4cout<<"In G4PreCompoundTransitions.cc useNGB="<<useNGB<<G4endl; |
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| 73 | //G4cout<<"In G4PreCompoundTransitions.cc useCEMtr="<<useCEMtr<<G4endl; |
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| 74 | |
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[819] | 75 | // Fermi energy |
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| 76 | const G4double FermiEnergy = G4PreCompoundParameters::GetAddress()->GetFermiEnergy(); |
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| 77 | |
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| 78 | // Nuclear radius |
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| 79 | const G4double r0 = G4PreCompoundParameters::GetAddress()->GetTransitionsr0(); |
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| 80 | |
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| 81 | // In order to calculate the level density parameter |
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| 82 | // G4EvaporationLevelDensityParameter theLDP; |
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| 83 | |
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| 84 | // Number of holes |
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| 85 | G4double H = aFragment.GetNumberOfHoles(); |
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| 86 | // Number of Particles |
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| 87 | G4double P = aFragment.GetNumberOfParticles(); |
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| 88 | // Number of Excitons |
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| 89 | G4double N = P+H; |
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| 90 | // Nucleus |
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| 91 | G4double A = aFragment.GetA(); |
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| 92 | G4double Z = static_cast<G4double>(aFragment.GetZ()); |
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| 93 | G4double U = aFragment.GetExcitationEnergy(); |
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| 94 | |
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[962] | 95 | if(U<10*eV) return 0.0; |
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[819] | 96 | |
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[962] | 97 | //J. M. Quesada (Feb. 08) new physics |
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| 98 | // OPT=1 Transitions are calculated according to Gudima's paper (original in G4PreCompound from VL) |
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| 99 | // OPT=2 Transitions are calculated according to Gupta's formulae |
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| 100 | // |
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| 101 | |
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| 102 | |
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| 103 | |
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| 104 | if (useCEMtr){ |
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[819] | 105 | |
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[962] | 106 | |
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| 107 | // Relative Energy (T_{rel}) |
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| 108 | G4double RelativeEnergy = (8.0/5.0)*FermiEnergy + U/N; |
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| 109 | |
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| 110 | // Sample kind of nucleon-projectile |
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| 111 | G4bool ChargedNucleon(false); |
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| 112 | G4double chtest = 0.5; |
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| 113 | if (P > 0) chtest = aFragment.GetNumberOfCharged()/P; |
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| 114 | if (G4UniformRand() < chtest) ChargedNucleon = true; |
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| 115 | |
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| 116 | // Relative Velocity: |
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| 117 | // <V_{rel}>^2 |
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| 118 | G4double RelativeVelocitySqr(0.0); |
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| 119 | if (ChargedNucleon) RelativeVelocitySqr = 2.0*RelativeEnergy/proton_mass_c2; |
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| 120 | else RelativeVelocitySqr = 2.0*RelativeEnergy/neutron_mass_c2; |
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| 121 | |
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| 122 | // <V_{rel}> |
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| 123 | G4double RelativeVelocity = std::sqrt(RelativeVelocitySqr); |
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| 124 | |
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| 125 | // Proton-Proton Cross Section |
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| 126 | G4double ppXSection = (10.63/RelativeVelocitySqr - 29.92/RelativeVelocity + 42.9)*millibarn; |
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| 127 | // Proton-Neutron Cross Section |
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| 128 | G4double npXSection = (34.10/RelativeVelocitySqr - 82.20/RelativeVelocity + 82.2)*millibarn; |
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| 129 | |
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| 130 | // Averaged Cross Section: \sigma(V_{rel}) |
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| 131 | // G4double AveragedXSection = (ppXSection+npXSection)/2.0; |
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| 132 | G4double AveragedXSection(0.0); |
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| 133 | if (ChargedNucleon) |
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| 134 | { |
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| 135 | //JMQ: small bug fixed |
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| 136 | // AveragedXSection = ((Z-1.0) * ppXSection + (A-Z-1.0) * npXSection) / (A-1.0); |
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| 137 | AveragedXSection = ((Z-1.0) * ppXSection + (A-Z) * npXSection) / (A-1.0); |
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| 138 | } |
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| 139 | else |
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| 140 | { |
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| 141 | AveragedXSection = ((A-Z-1.0) * ppXSection + Z * npXSection) / (A-1.0); |
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| 142 | } |
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| 143 | |
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| 144 | // Fermi relative energy ratio |
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| 145 | G4double FermiRelRatio = FermiEnergy/RelativeEnergy; |
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| 146 | |
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| 147 | // This factor is introduced to take into account the Pauli principle |
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| 148 | G4double PauliFactor = 1.0 - (7.0/5.0)*FermiRelRatio; |
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| 149 | if (FermiRelRatio > 0.5) PauliFactor += (2.0/5.0)*FermiRelRatio*std::pow(2.0 - (1.0/FermiRelRatio), 5.0/2.0); |
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| 150 | |
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| 151 | // Interaction volume |
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| 152 | // G4double Vint = (4.0/3.0)*pi*std::pow(2.0*r0 + hbarc/(proton_mass_c2*RelativeVelocity) , 3.0); |
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| 153 | G4double xx=2.0*r0 + hbarc/(proton_mass_c2*RelativeVelocity); |
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| 154 | G4double Vint = (4.0/3.0)*pi*xx*xx*xx; |
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| 155 | |
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| 156 | // Transition probability for \Delta n = +2 |
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| 157 | |
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| 158 | TransitionProb1 = AveragedXSection*PauliFactor*std::sqrt(2.0*RelativeEnergy/proton_mass_c2)/Vint; |
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[1196] | 159 | |
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| 160 | //JMQ 281009 phenomenological factor in order to increase equilibrium contribution |
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[1228] | 161 | // G4double factor=5.0; |
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| 162 | // TransitionProb1 *= factor; |
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[1196] | 163 | // |
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[962] | 164 | if (TransitionProb1 < 0.0) TransitionProb1 = 0.0; |
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| 165 | |
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| 166 | G4double a = G4PreCompoundParameters::GetAddress()->GetLevelDensity(); |
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| 167 | // GE = g*E where E is Excitation Energy |
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| 168 | G4double GE = (6.0/pi2)*a*A*U; |
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| 169 | |
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| 170 | G4double Fph = ((P*P+H*H+P-H)/4.0 - H/2.0); |
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| 171 | |
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| 172 | //G4bool NeverGoBack(false); |
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| 173 | G4bool NeverGoBack; |
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| 174 | if(useNGB) NeverGoBack=true; |
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| 175 | else NeverGoBack=false; |
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| 176 | |
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| 177 | |
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| 178 | //JMQ/AH bug fixed: if (U-Fph < 0.0) NeverGoBack = true; |
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| 179 | if (GE-Fph < 0.0) NeverGoBack = true; |
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| 180 | |
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| 181 | // F(p+1,h+1) |
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| 182 | G4double Fph1 = Fph + N/2.0; |
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| 183 | |
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| 184 | G4double ProbFactor = std::pow((GE-Fph)/(GE-Fph1),N+1.0); |
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| 185 | |
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| 186 | |
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| 187 | if (NeverGoBack) |
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| 188 | { |
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[819] | 189 | TransitionProb2 = 0.0; |
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| 190 | TransitionProb3 = 0.0; |
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[962] | 191 | } |
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| 192 | else |
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| 193 | { |
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| 194 | // Transition probability for \Delta n = -2 (at F(p,h) = 0) |
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| 195 | TransitionProb2 = TransitionProb1 * ProbFactor * (P*H*(N+1.0)*(N-2.0))/((GE-Fph)*(GE-Fph)); |
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| 196 | if (TransitionProb2 < 0.0) TransitionProb2 = 0.0; |
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| 197 | |
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| 198 | // Transition probability for \Delta n = 0 (at F(p,h) = 0) |
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| 199 | TransitionProb3 = TransitionProb1* ((N+1.0)/N) * ProbFactor * (P*(P-1.0) + 4.0*P*H + H*(H-1.0))/(GE-Fph); |
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| 200 | if (TransitionProb3 < 0.0) TransitionProb3 = 0.0; |
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| 201 | } |
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| 202 | |
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| 203 | // G4cout<<"U = "<<U<<G4endl; |
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| 204 | // G4cout<<"N="<<N<<" P="<<P<<" H="<<H<<G4endl; |
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| 205 | // G4cout<<"l+ ="<<TransitionProb1<<" l- ="<< TransitionProb2<<" l0 ="<< TransitionProb3<<G4endl; |
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[1055] | 206 | return TransitionProb1 + TransitionProb2 + TransitionProb3; |
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| 207 | } |
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[962] | 208 | |
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| 209 | else { |
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| 210 | //JMQ: Transition probabilities from Gupta's work |
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| 211 | |
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| 212 | G4double a = G4PreCompoundParameters::GetAddress()->GetLevelDensity(); |
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| 213 | // GE = g*E where E is Excitation Energy |
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| 214 | G4double GE = (6.0/pi2)*a*A*U; |
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[1196] | 215 | |
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[962] | 216 | G4double Kmfp=2.; |
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[1196] | 217 | |
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[962] | 218 | TransitionProb1=1./Kmfp*3./8.*1./c_light*1.0e-9*(1.4e+21*U-2./(N+1)*6.0e+18*U*U); |
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| 219 | if (TransitionProb1 < 0.0) TransitionProb1 = 0.0; |
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| 220 | |
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| 221 | if (useNGB){ |
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| 222 | TransitionProb2=0.; |
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| 223 | TransitionProb3=0.; |
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[819] | 224 | } |
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[962] | 225 | else{ |
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| 226 | if (N<=1) TransitionProb2=0. ; |
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| 227 | else TransitionProb2=1./Kmfp*3./8.*1./c_light*1.0e-9*(N-1.)*(N-2.)*P*H/(GE*GE)*(1.4e+21*U - 2./(N-1)*6.0e+18*U*U); |
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[819] | 228 | if (TransitionProb2 < 0.0) TransitionProb2 = 0.0; |
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[962] | 229 | TransitionProb3=0.; |
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[819] | 230 | } |
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[962] | 231 | |
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| 232 | // G4cout<<"U = "<<U<<G4endl; |
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| 233 | // G4cout<<"N="<<N<<" P="<<P<<" H="<<H<<G4endl; |
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| 234 | // G4cout<<"l+ ="<<TransitionProb1<<" l- ="<< TransitionProb2<<" l0 ="<< TransitionProb3<<G4endl; |
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| 235 | return TransitionProb1 + TransitionProb2 + TransitionProb3; |
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| 236 | } |
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[819] | 237 | } |
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| 238 | |
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| 239 | |
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| 240 | G4Fragment G4PreCompoundTransitions::PerformTransition(const G4Fragment & aFragment) |
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| 241 | { |
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| 242 | G4Fragment result(aFragment); |
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| 243 | G4double ChosenTransition = G4UniformRand()*(TransitionProb1 + TransitionProb2 + TransitionProb3); |
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| 244 | G4int deltaN = 0; |
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| 245 | G4int Nexcitons = result.GetNumberOfExcitons(); |
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| 246 | if (ChosenTransition <= TransitionProb1) |
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| 247 | { |
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| 248 | // Number of excitons is increased on \Delta n = +2 |
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| 249 | deltaN = 2; |
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| 250 | } |
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| 251 | else if (ChosenTransition <= TransitionProb1+TransitionProb2) |
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| 252 | { |
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| 253 | // Number of excitons is increased on \Delta n = -2 |
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| 254 | deltaN = -2; |
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| 255 | } |
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| 256 | |
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[1055] | 257 | // AH/JMQ: Randomly decrease the number of charges if deltaN is -2 and in proportion |
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| 258 | // to the number charges w.r.t. number of particles, PROVIDED that there are charged particles |
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| 259 | if(deltaN < 0 && G4UniformRand() <= |
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| 260 | static_cast<G4double>(result.GetNumberOfCharged())/static_cast<G4double>(result.GetNumberOfParticles()) |
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| 261 | && (result.GetNumberOfCharged() >= 1)) { |
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[819] | 262 | result.SetNumberOfCharged(result.GetNumberOfCharged()+deltaN/2); // deltaN is negative! |
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[1055] | 263 | } |
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[819] | 264 | |
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[1055] | 265 | // JMQ the following lines have to be before SetNumberOfCharged, otherwise the check on |
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| 266 | // number of charged vs. number of particles fails |
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[819] | 267 | result.SetNumberOfParticles(result.GetNumberOfParticles()+deltaN/2); |
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| 268 | result.SetNumberOfHoles(result.GetNumberOfHoles()+deltaN/2); |
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| 269 | |
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[1055] | 270 | // With weight Z/A, number of charged particles is increased with +1 |
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[819] | 271 | if ( ( deltaN > 0 ) && |
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| 272 | (G4UniformRand() <= static_cast<G4double>(result.GetZ()-result.GetNumberOfCharged())/ |
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[1055] | 273 | std::max(static_cast<G4double>(result.GetA()-Nexcitons),1.))) |
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[819] | 274 | { |
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| 275 | result.SetNumberOfCharged(result.GetNumberOfCharged()+deltaN/2); |
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| 276 | } |
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| 277 | |
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| 278 | // Number of charged can not be greater that number of particles |
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| 279 | if ( result.GetNumberOfParticles() < result.GetNumberOfCharged() ) |
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| 280 | { |
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| 281 | result.SetNumberOfCharged(result.GetNumberOfParticles()); |
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| 282 | } |
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| 283 | |
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| 284 | return result; |
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| 285 | } |
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| 286 | |
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