[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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| 26 | // |
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| 27 | // |
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| 28 | // Hadronic Process: Nuclear De-excitations |
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| 29 | // by V. Lara (Sept 2001) |
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| 30 | // |
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| 31 | |
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| 32 | |
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| 33 | #include "G4GEMProbability.hh" |
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| 34 | #include "G4PairingCorrection.hh" |
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| 35 | |
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| 36 | |
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| 37 | |
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| 38 | G4GEMProbability::G4GEMProbability(const G4GEMProbability &) : G4VEmissionProbability() |
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| 39 | { |
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| 40 | throw G4HadronicException(__FILE__, __LINE__, "G4GEMProbability::copy_constructor meant to not be accessable"); |
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| 41 | } |
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| 42 | |
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| 43 | |
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| 44 | |
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| 45 | |
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| 46 | const G4GEMProbability & G4GEMProbability:: |
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| 47 | operator=(const G4GEMProbability &) |
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| 48 | { |
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| 49 | throw G4HadronicException(__FILE__, __LINE__, "G4GEMProbability::operator= meant to not be accessable"); |
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| 50 | return *this; |
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| 51 | } |
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| 52 | |
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| 53 | |
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| 54 | G4bool G4GEMProbability::operator==(const G4GEMProbability &) const |
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| 55 | { |
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| 56 | return false; |
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| 57 | } |
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| 58 | |
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| 59 | G4bool G4GEMProbability::operator!=(const G4GEMProbability &) const |
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| 60 | { |
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| 61 | return true; |
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| 62 | } |
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| 63 | |
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| 64 | G4double G4GEMProbability::EmissionProbability(const G4Fragment & fragment, |
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| 65 | const G4double MaximalKineticEnergy) |
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| 66 | { |
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| 67 | G4double EmissionProbability = 0.0; |
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| 68 | |
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| 69 | if (MaximalKineticEnergy > 0.0 && fragment.GetExcitationEnergy() > 0.0) { |
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| 70 | G4double CoulombBarrier = GetCoulombBarrier(fragment); |
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| 71 | |
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| 72 | EmissionProbability = CalcProbability(fragment,MaximalKineticEnergy,CoulombBarrier); |
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| 73 | Normalization = EmissionProbability; |
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| 74 | // Next there is a loop over excited states for this channel summing probabilities |
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| 75 | if (ExcitationEnergies && ExcitationSpins && ExcitationLifetimes) { |
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| 76 | G4double SavedSpin = Spin; |
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| 77 | for (unsigned int i = 0; i < ExcitationEnergies->size(); i++) { |
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| 78 | Spin = ExcitationSpins->operator[](i); |
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| 79 | // substract excitation energies |
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| 80 | G4double Tmax = MaximalKineticEnergy - ExcitationEnergies->operator[](i); |
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| 81 | if (Tmax > 0.0) { |
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| 82 | G4double width = CalcProbability(fragment,Tmax,CoulombBarrier); |
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| 83 | // update probability |
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| 84 | if (hbar_Planck*std::log(2.0)/width < ExcitationLifetimes->operator[](i)) { |
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| 85 | EmissionProbability += width; |
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| 86 | } |
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| 87 | } |
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| 88 | } |
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| 89 | // Restore Spin |
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| 90 | Spin = SavedSpin; |
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| 91 | } |
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| 92 | } |
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| 93 | return EmissionProbability; |
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| 94 | } |
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| 95 | |
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| 96 | G4double G4GEMProbability::CalcProbability(const G4Fragment & fragment, |
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| 97 | const G4double MaximalKineticEnergy, |
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| 98 | const G4double V) |
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| 99 | // Calculate integrated probability (width) for evaporation channel |
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| 100 | { |
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| 101 | G4double ResidualA = static_cast<G4double>(fragment.GetA() - theA); |
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| 102 | // G4double ResidualZ = static_cast<G4double>(fragment.GetZ() - theZ); |
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| 103 | G4double U = fragment.GetExcitationEnergy(); |
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| 104 | |
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| 105 | G4double NuclearMass = G4ParticleTable::GetParticleTable()-> |
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| 106 | GetIonTable()->GetNucleusMass(theZ,theA); |
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| 107 | |
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| 108 | G4double a = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(fragment.GetA()), |
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| 109 | static_cast<G4int>(fragment.GetZ()),U); |
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| 110 | G4double delta0 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(fragment.GetA()), |
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| 111 | static_cast<G4int>(fragment.GetZ())); |
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| 112 | |
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| 113 | G4double Alpha = CalcAlphaParam(fragment); |
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| 114 | G4double Beta = CalcBetaParam(fragment); |
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| 115 | |
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| 116 | |
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| 117 | G4double Ux = (2.5 + 150.0/ResidualA)*MeV; |
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| 118 | G4double Ex = Ux + delta0; |
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| 119 | G4double T = 1.0/(std::sqrt(a/Ux) - 1.5/Ux); |
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| 120 | G4double E0 = Ex - T*(std::log(T*MeV) - std::log(a/MeV)/4.0 - 1.25*std::log(Ux*MeV) + 2.0*std::sqrt(a*Ux)); |
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| 121 | |
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| 122 | G4double Width; |
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| 123 | G4double InitialLevelDensity; |
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| 124 | if ( MaximalKineticEnergy < Ex ) { |
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| 125 | G4double t = MaximalKineticEnergy/T; |
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| 126 | Width = (I1(t,t) + (Beta+V)*I0(t))/std::exp(E0/T); |
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| 127 | InitialLevelDensity = (pi/12.0)*std::exp((U-E0)/T)/T; |
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| 128 | } else { |
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| 129 | G4double t = MaximalKineticEnergy/T; |
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| 130 | G4double tx = Ex/T; |
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| 131 | G4double s = 2.0*std::sqrt(a*(MaximalKineticEnergy-delta0)); |
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| 132 | G4double sx = 2.0*std::sqrt(a*(Ex-delta0)); |
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| 133 | Width = I1(t,tx)/std::exp(E0/T) + I3(s,sx)*std::exp(s)/(std::sqrt(2.0)*a); |
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| 134 | // For charged particles (Beta+V) = 0 beacuse Beta = -V |
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| 135 | if (theZ == 0) { |
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| 136 | Width += (Beta+V)*(I0(tx)/std::exp(E0/T) + 2.0*std::sqrt(2.0)*I2(s,sx)*std::exp(s)); |
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| 137 | } |
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| 138 | InitialLevelDensity = (pi/12.0)*std::exp(2*std::sqrt(a*(U-delta0)))/std::pow(a*std::pow(U-delta0,5.0),1.0/4.0); |
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| 139 | } |
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| 140 | |
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| 141 | |
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| 142 | G4double g = (2.0*Spin+1.0)*NuclearMass/(pi2* hbar_Planck*hbar_Planck); |
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| 143 | |
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| 144 | G4double RN = 0.0; |
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| 145 | if (theA > 4) |
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| 146 | { |
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| 147 | G4double R1 = std::pow(ResidualA,1.0/3.0); |
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| 148 | G4double R2 = std::pow(G4double(theA),1.0/3.0); |
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| 149 | RN = 1.12*(R1 + R2) - 0.86*((R1+R2)/(R1*R2)); |
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| 150 | RN *= fermi; |
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| 151 | } |
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| 152 | else |
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| 153 | { |
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| 154 | RN = 1.5*fermi; |
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| 155 | } |
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| 156 | G4double GeometricalXS = pi*RN*RN*std::pow(ResidualA,2./3.); |
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| 157 | |
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| 158 | |
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| 159 | Width *= std::sqrt(pi)*g*GeometricalXS*Alpha/(12.0*InitialLevelDensity); |
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| 160 | return Width; |
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| 161 | } |
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| 162 | |
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| 163 | |
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| 164 | |
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| 165 | |
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| 166 | G4double G4GEMProbability::I0(const G4double t) |
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| 167 | { |
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| 168 | G4double result = (std::exp(t) - 1.0); |
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| 169 | return result; |
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| 170 | } |
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| 171 | |
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| 172 | G4double G4GEMProbability::I1(const G4double t, const G4double tx) |
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| 173 | { |
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| 174 | G4double result = t - tx + 1.0; |
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| 175 | result *= std::exp(tx); |
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| 176 | result -= (t + 1.0); |
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| 177 | return result; |
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| 178 | } |
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| 179 | |
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| 180 | |
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| 181 | G4double G4GEMProbability::I2(const G4double s, const G4double sx) |
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| 182 | { |
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| 183 | G4double S = 1.0/std::sqrt(s); |
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| 184 | G4double Sx = 1.0/std::sqrt(sx); |
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| 185 | |
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| 186 | G4double p1 = S*S*S*( 1.0 + S*S*( 1.5 + 3.75*S*S) ); |
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| 187 | G4double p2 = Sx*Sx*Sx*( 1.0 + Sx*Sx*( 1.5 + 3.75*Sx*Sx) )*std::exp(sx-s); |
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| 188 | |
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| 189 | return p1-p2; |
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| 190 | } |
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| 191 | |
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| 192 | G4double G4GEMProbability::I3(const G4double s, const G4double sx) |
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| 193 | { |
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| 194 | G4double s2 = s*s; |
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| 195 | G4double sx2 = sx*sx; |
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| 196 | G4double S = 1.0/std::sqrt(s); |
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| 197 | G4double S2 = S*S; |
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| 198 | G4double Sx = 1.0/std::sqrt(sx); |
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| 199 | G4double Sx2 = Sx*Sx; |
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| 200 | |
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| 201 | G4double p1 = S *(2.0 + S2 *( 4.0 + S2 *( 13.5 + S2 *( 60.0 + S2 * 325.125 )))); |
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| 202 | G4double p2 = Sx*Sx2 *( |
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| 203 | (s2-sx2) + Sx2 *( |
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| 204 | (1.5*s2+0.5*sx2) + Sx2 *( |
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| 205 | (3.75*s2+0.25*sx2) + Sx2 *( |
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| 206 | (12.875*s2+0.625*sx2) + Sx2 *( |
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| 207 | (59.0625*s2+0.9375*sx2) + Sx2 *(324.8*s2+3.28*sx2)))))); |
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| 208 | |
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| 209 | p2 *= std::exp(sx-s); |
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| 210 | |
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| 211 | return p1-p2; |
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| 212 | } |
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