[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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[1340] | 26 | // $Id: G4PreCompoundTransitions.cc,v 1.27 2010/10/20 00:47:46 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-03-ref-09 $ |
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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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[1340] | 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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[1340] | 43 | // 30.10.2009 J.M.Quesada: CEM transition probabilities have been renormalized |
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[1196] | 44 | // (IAEA benchmark) |
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[1340] | 45 | // 20.08.2010 V.Ivanchenko move constructor and destructor to the source and |
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| 46 | // optimise the code |
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[1196] | 47 | // |
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[1340] | 48 | |
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[819] | 49 | #include "G4PreCompoundTransitions.hh" |
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| 50 | #include "G4HadronicException.hh" |
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[1340] | 51 | #include "G4PreCompoundParameters.hh" |
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| 52 | #include "G4Proton.hh" |
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| 53 | #include "Randomize.hh" |
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| 54 | #include "G4Pow.hh" |
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[819] | 55 | |
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[1340] | 56 | G4PreCompoundTransitions::G4PreCompoundTransitions() |
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[819] | 57 | { |
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[1340] | 58 | proton = G4Proton::Proton(); |
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| 59 | FermiEnergy = G4PreCompoundParameters::GetAddress()->GetFermiEnergy(); |
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| 60 | r0 = G4PreCompoundParameters::GetAddress()->GetTransitionsr0(); |
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| 61 | aLDP = G4PreCompoundParameters::GetAddress()->GetLevelDensity(); |
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| 62 | g4pow = G4Pow::GetInstance(); |
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[819] | 63 | } |
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| 64 | |
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[1340] | 65 | G4PreCompoundTransitions::~G4PreCompoundTransitions() |
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| 66 | {} |
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[819] | 67 | |
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[1340] | 68 | // Calculates transition probabilities with |
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| 69 | // DeltaN = +2 (Trans1) -2 (Trans2) and 0 (Trans3) |
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[819] | 70 | G4double G4PreCompoundTransitions:: |
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| 71 | CalculateProbability(const G4Fragment & aFragment) |
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| 72 | { |
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| 73 | // Number of holes |
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[1340] | 74 | G4int H = aFragment.GetNumberOfHoles(); |
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[819] | 75 | // Number of Particles |
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[1340] | 76 | G4int P = aFragment.GetNumberOfParticles(); |
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[819] | 77 | // Number of Excitons |
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[1340] | 78 | G4int N = P+H; |
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[819] | 79 | // Nucleus |
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[1340] | 80 | G4int A = aFragment.GetA_asInt(); |
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| 81 | G4int Z = aFragment.GetZ_asInt(); |
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[819] | 82 | G4double U = aFragment.GetExcitationEnergy(); |
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[1340] | 83 | |
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| 84 | //G4cout << aFragment << G4endl; |
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[819] | 85 | |
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[1340] | 86 | if(U < 10*eV) { return 0.0; } |
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[819] | 87 | |
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[962] | 88 | //J. M. Quesada (Feb. 08) new physics |
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[1340] | 89 | // OPT=1 Transitions are calculated according to Gudima's paper |
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| 90 | // (original in G4PreCompound from VL) |
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[962] | 91 | // OPT=2 Transitions are calculated according to Gupta's formulae |
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| 92 | // |
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| 93 | if (useCEMtr){ |
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[819] | 94 | |
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[962] | 95 | // Relative Energy (T_{rel}) |
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[1340] | 96 | G4double RelativeEnergy = 1.6*FermiEnergy + U/G4double(N); |
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[962] | 97 | |
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| 98 | // Sample kind of nucleon-projectile |
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| 99 | G4bool ChargedNucleon(false); |
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| 100 | G4double chtest = 0.5; |
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[1340] | 101 | if (P > 0) { |
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| 102 | chtest = G4double(aFragment.GetNumberOfCharged())/G4double(P); |
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| 103 | } |
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| 104 | if (G4UniformRand() < chtest) { ChargedNucleon = true; } |
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[962] | 105 | |
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| 106 | // Relative Velocity: |
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| 107 | // <V_{rel}>^2 |
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| 108 | G4double RelativeVelocitySqr(0.0); |
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[1340] | 109 | if (ChargedNucleon) { |
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| 110 | RelativeVelocitySqr = 2.0*RelativeEnergy/CLHEP::proton_mass_c2; |
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| 111 | } else { |
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| 112 | RelativeVelocitySqr = 2.0*RelativeEnergy/CLHEP::neutron_mass_c2; |
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| 113 | } |
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[962] | 114 | |
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| 115 | // <V_{rel}> |
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| 116 | G4double RelativeVelocity = std::sqrt(RelativeVelocitySqr); |
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| 117 | |
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| 118 | // Proton-Proton Cross Section |
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[1340] | 119 | G4double ppXSection = |
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| 120 | (10.63/RelativeVelocitySqr - 29.92/RelativeVelocity + 42.9) |
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| 121 | * CLHEP::millibarn; |
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[962] | 122 | // Proton-Neutron Cross Section |
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[1340] | 123 | G4double npXSection = |
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| 124 | (34.10/RelativeVelocitySqr - 82.20/RelativeVelocity + 82.2) |
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| 125 | * CLHEP::millibarn; |
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[962] | 126 | |
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| 127 | // Averaged Cross Section: \sigma(V_{rel}) |
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| 128 | // G4double AveragedXSection = (ppXSection+npXSection)/2.0; |
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| 129 | G4double AveragedXSection(0.0); |
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| 130 | if (ChargedNucleon) |
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| 131 | { |
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| 132 | //JMQ: small bug fixed |
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[1340] | 133 | //AveragedXSection=((Z-1.0) * ppXSection + (A-Z-1.0) * npXSection)/(A-1.0); |
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| 134 | AveragedXSection = ((Z-1)*ppXSection + (A-Z)*npXSection)/G4double(A-1); |
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[962] | 135 | } |
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| 136 | else |
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| 137 | { |
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[1340] | 138 | AveragedXSection = ((A-Z-1)*ppXSection + Z*npXSection)/G4double(A-1); |
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| 139 | //AveragedXSection = ((A-Z-1)*npXSection + Z*ppXSection)/G4double(A-1); |
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[962] | 140 | } |
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| 141 | |
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| 142 | // Fermi relative energy ratio |
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| 143 | G4double FermiRelRatio = FermiEnergy/RelativeEnergy; |
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| 144 | |
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| 145 | // This factor is introduced to take into account the Pauli principle |
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[1340] | 146 | G4double PauliFactor = 1.0 - 1.4*FermiRelRatio; |
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| 147 | if (FermiRelRatio > 0.5) { |
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| 148 | G4double x = 2.0 - 1.0/FermiRelRatio; |
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| 149 | PauliFactor += 0.4*FermiRelRatio*x*x*std::sqrt(x); |
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| 150 | //PauliFactor += |
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| 151 | //(2.0/5.0)*FermiRelRatio*std::pow(2.0 - (1.0/FermiRelRatio), 5.0/2.0); |
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| 152 | } |
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[962] | 153 | // Interaction volume |
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[1340] | 154 | // G4double Vint = (4.0/3.0) |
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| 155 | //*pi*std::pow(2.0*r0 + hbarc/(proton_mass_c2*RelativeVelocity) , 3.0); |
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| 156 | G4double xx = 2.0*r0 + hbarc/(CLHEP::proton_mass_c2*RelativeVelocity); |
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| 157 | // G4double Vint = (4.0/3.0)*CLHEP::pi*xx*xx*xx; |
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| 158 | G4double Vint = CLHEP::pi*xx*xx*xx/0.75; |
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[962] | 159 | |
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| 160 | // Transition probability for \Delta n = +2 |
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| 161 | |
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[1340] | 162 | TransitionProb1 = AveragedXSection*PauliFactor |
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| 163 | *std::sqrt(2.0*RelativeEnergy/CLHEP::proton_mass_c2)/Vint; |
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[1196] | 164 | |
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[1340] | 165 | //JMQ 281009 phenomenological factor in order to increase |
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| 166 | // equilibrium contribution |
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| 167 | // G4double factor=5.0; |
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| 168 | // TransitionProb1 *= factor; |
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| 169 | // |
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| 170 | if (TransitionProb1 < 0.0) { TransitionProb1 = 0.0; } |
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[962] | 171 | |
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| 172 | // GE = g*E where E is Excitation Energy |
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[1340] | 173 | G4double GE = (6.0/pi2)*aLDP*A*U; |
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[962] | 174 | |
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[1340] | 175 | //G4double Fph = ((P*P+H*H+P-H)/4.0 - H/2.0); |
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| 176 | G4double Fph = G4double(P*P+H*H+P-3*H)/4.0; |
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[962] | 177 | |
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[1340] | 178 | G4bool NeverGoBack(false); |
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| 179 | if(useNGB) { NeverGoBack=true; } |
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[962] | 180 | |
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| 181 | //JMQ/AH bug fixed: if (U-Fph < 0.0) NeverGoBack = true; |
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[1340] | 182 | if (GE-Fph < 0.0) { NeverGoBack = true; } |
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[962] | 183 | |
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| 184 | // F(p+1,h+1) |
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| 185 | G4double Fph1 = Fph + N/2.0; |
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| 186 | |
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[1340] | 187 | G4double ProbFactor = g4pow->powN((GE-Fph)/(GE-Fph1),N+1); |
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[962] | 188 | |
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| 189 | if (NeverGoBack) |
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| 190 | { |
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[1340] | 191 | TransitionProb2 = 0.0; |
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| 192 | TransitionProb3 = 0.0; |
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[962] | 193 | } |
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| 194 | else |
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| 195 | { |
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| 196 | // Transition probability for \Delta n = -2 (at F(p,h) = 0) |
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[1340] | 197 | TransitionProb2 = |
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| 198 | TransitionProb1 * ProbFactor * (P*H*(N+1)*(N-2))/((GE-Fph)*(GE-Fph)); |
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| 199 | if (TransitionProb2 < 0.0) { TransitionProb2 = 0.0; } |
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[962] | 200 | |
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| 201 | // Transition probability for \Delta n = 0 (at F(p,h) = 0) |
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[1340] | 202 | TransitionProb3 = TransitionProb1*(N+1)* ProbFactor |
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| 203 | * (P*(P-1) + 4.0*P*H + H*(H-1))/(N*(GE-Fph)); |
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| 204 | if (TransitionProb3 < 0.0) { TransitionProb3 = 0.0; } |
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[962] | 205 | } |
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[1340] | 206 | } else { |
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| 207 | //JMQ: Transition probabilities from Gupta's work |
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[962] | 208 | // GE = g*E where E is Excitation Energy |
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[1340] | 209 | G4double GE = (6.0/pi2)*aLDP*A*U; |
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[1196] | 210 | |
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[962] | 211 | G4double Kmfp=2.; |
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[1196] | 212 | |
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[1340] | 213 | //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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| 214 | TransitionProb1 = 3.0e-9*(1.4e+21*U - 1.2e+19*U*U/G4double(N+1)) |
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| 215 | /(8*Kmfp*CLHEP::c_light); |
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| 216 | if (TransitionProb1 < 0.0) { TransitionProb1 = 0.0; } |
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| 217 | |
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| 218 | TransitionProb2=0.; |
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| 219 | TransitionProb3=0.; |
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[962] | 220 | |
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[1340] | 221 | if (!useNGB && N > 1) { |
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| 222 | // 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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| 223 | TransitionProb2 = |
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| 224 | 3.0e-9*(N-2)*P*H*(1.4e+21*U*(N-1) - 1.2e+19*U*U)/(8*Kmfp*c_light*GE*GE); |
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[819] | 225 | if (TransitionProb2 < 0.0) TransitionProb2 = 0.0; |
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| 226 | } |
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[962] | 227 | } |
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[1340] | 228 | // G4cout<<"U = "<<U<<G4endl; |
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| 229 | // G4cout<<"N="<<N<<" P="<<P<<" H="<<H<<G4endl; |
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| 230 | // G4cout<<"l+ ="<<TransitionProb1<<" l- ="<< TransitionProb2 |
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| 231 | // <<" l0 ="<< TransitionProb3<<G4endl; |
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| 232 | return TransitionProb1 + TransitionProb2 + TransitionProb3; |
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[819] | 233 | } |
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| 234 | |
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[1340] | 235 | void G4PreCompoundTransitions::PerformTransition(G4Fragment & result) |
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[819] | 236 | { |
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[1340] | 237 | G4double ChosenTransition = |
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| 238 | G4UniformRand()*(TransitionProb1 + TransitionProb2 + TransitionProb3); |
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[819] | 239 | G4int deltaN = 0; |
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[1340] | 240 | // G4int Nexcitons = result.GetNumberOfExcitons(); |
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| 241 | G4int Npart = result.GetNumberOfParticles(); |
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| 242 | G4int Ncharged = result.GetNumberOfCharged(); |
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| 243 | G4int Nholes = result.GetNumberOfHoles(); |
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[819] | 244 | if (ChosenTransition <= TransitionProb1) |
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| 245 | { |
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| 246 | // Number of excitons is increased on \Delta n = +2 |
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| 247 | deltaN = 2; |
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| 248 | } |
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| 249 | else if (ChosenTransition <= TransitionProb1+TransitionProb2) |
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| 250 | { |
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| 251 | // Number of excitons is increased on \Delta n = -2 |
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| 252 | deltaN = -2; |
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| 253 | } |
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| 254 | |
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[1340] | 255 | // AH/JMQ: Randomly decrease the number of charges if deltaN is -2 and |
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| 256 | // in proportion to the number charges w.r.t. number of particles, |
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| 257 | // PROVIDED that there are charged particles |
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| 258 | deltaN /= 2; |
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[819] | 259 | |
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[1340] | 260 | //G4cout << "deltaN= " << deltaN << G4endl; |
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| 261 | |
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[1055] | 262 | // JMQ the following lines have to be before SetNumberOfCharged, otherwise the check on |
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| 263 | // number of charged vs. number of particles fails |
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[1340] | 264 | result.SetNumberOfParticles(Npart+deltaN); |
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| 265 | result.SetNumberOfHoles(Nholes+deltaN); |
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[819] | 266 | |
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[1340] | 267 | if(deltaN < 0) { |
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| 268 | if( Ncharged >= 1 && G4int(Npart*G4UniformRand()) <= Ncharged) |
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| 269 | { |
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| 270 | result.SetNumberOfCharged(Ncharged+deltaN); // deltaN is negative! |
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| 271 | } |
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| 272 | |
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| 273 | } else if ( deltaN > 0 ) { |
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| 274 | // With weight Z/A, number of charged particles is increased with +1 |
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| 275 | G4int A = result.GetA_asInt(); |
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| 276 | G4int Z = result.GetZ_asInt(); |
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| 277 | if( G4int(std::max(1, A - Npart)*G4UniformRand()) <= Z) |
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| 278 | { |
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| 279 | result.SetNumberOfCharged(Ncharged+deltaN); |
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| 280 | } |
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| 281 | } |
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[819] | 282 | |
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| 283 | // Number of charged can not be greater that number of particles |
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[1340] | 284 | if ( Npart < Ncharged ) |
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[819] | 285 | { |
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[1340] | 286 | result.SetNumberOfCharged(Npart); |
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[819] | 287 | } |
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[1340] | 288 | //G4cout << "### After transition" << G4endl; |
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| 289 | //G4cout << result << G4endl; |
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[819] | 290 | } |
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| 291 | |
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