[819] | 1 | // |
---|
| 2 | // ******************************************************************** |
---|
| 3 | // * License and Disclaimer * |
---|
| 4 | // * * |
---|
| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
| 7 | // * conditions of the Geant4 Software License, included in the file * |
---|
| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
| 9 | // * include a list of copyright holders. * |
---|
| 10 | // * * |
---|
| 11 | // * Neither the authors of this software system, nor their employing * |
---|
| 12 | // * institutes,nor the agencies providing financial support for this * |
---|
| 13 | // * work make any representation or warranty, express or implied, * |
---|
| 14 | // * regarding this software system or assume any liability for its * |
---|
| 15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
| 16 | // * for the full disclaimer and the limitation of liability. * |
---|
| 17 | // * * |
---|
| 18 | // * This code implementation is the result of the scientific and * |
---|
| 19 | // * technical work of the GEANT4 collaboration. * |
---|
| 20 | // * By using, copying, modifying or distributing the software (or * |
---|
| 21 | // * any work based on the software) you agree to acknowledge its * |
---|
| 22 | // * use in resulting scientific publications, and indicate your * |
---|
| 23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
| 24 | // ******************************************************************** |
---|
| 25 | // |
---|
[962] | 26 | // $Id: G4PreCompoundTransitions.cc,v 1.20 2009/02/10 16:01:37 vnivanch Exp $ |
---|
| 27 | // GEANT4 tag $Name: geant4-09-02-ref-02 $ |
---|
[819] | 28 | // |
---|
[962] | 29 | // ------------------------------------------------------------------- |
---|
[819] | 30 | // |
---|
[962] | 31 | // GEANT4 Class file |
---|
| 32 | // |
---|
| 33 | // |
---|
| 34 | // File name: G4PreCompoundIon |
---|
| 35 | // |
---|
| 36 | // Author: V.Lara |
---|
| 37 | // |
---|
| 38 | // Modified: |
---|
| 39 | // 16.02.2008 J. M. Quesada fixed bugs |
---|
| 40 | // 06.09.2008 J. M. Quesada added external choices for: |
---|
| 41 | // - "never go back" hipothesis (useNGB=true) |
---|
| 42 | // - CEM transition probabilities (useCEMtr=true) |
---|
[819] | 43 | |
---|
| 44 | #include "G4PreCompoundTransitions.hh" |
---|
| 45 | #include "G4HadronicException.hh" |
---|
| 46 | |
---|
| 47 | const G4PreCompoundTransitions & G4PreCompoundTransitions:: |
---|
| 48 | operator=(const G4PreCompoundTransitions &) |
---|
| 49 | { |
---|
| 50 | throw G4HadronicException(__FILE__, __LINE__, "G4PreCompoundTransitions::operator= meant to not be accessable"); |
---|
| 51 | return *this; |
---|
| 52 | } |
---|
| 53 | |
---|
| 54 | |
---|
| 55 | G4bool G4PreCompoundTransitions::operator==(const G4PreCompoundTransitions &) const |
---|
| 56 | { |
---|
| 57 | return false; |
---|
| 58 | } |
---|
| 59 | |
---|
| 60 | G4bool G4PreCompoundTransitions::operator!=(const G4PreCompoundTransitions &) const |
---|
| 61 | { |
---|
| 62 | return true; |
---|
| 63 | } |
---|
| 64 | |
---|
| 65 | |
---|
| 66 | G4double G4PreCompoundTransitions:: |
---|
| 67 | CalculateProbability(const G4Fragment & aFragment) |
---|
| 68 | { |
---|
[962] | 69 | //G4cout<<"In G4PreCompoundTransitions.cc useNGB="<<useNGB<<G4endl; |
---|
| 70 | //G4cout<<"In G4PreCompoundTransitions.cc useCEMtr="<<useCEMtr<<G4endl; |
---|
| 71 | |
---|
[819] | 72 | // Fermi energy |
---|
| 73 | const G4double FermiEnergy = G4PreCompoundParameters::GetAddress()->GetFermiEnergy(); |
---|
| 74 | |
---|
| 75 | // Nuclear radius |
---|
| 76 | const G4double r0 = G4PreCompoundParameters::GetAddress()->GetTransitionsr0(); |
---|
| 77 | |
---|
| 78 | // In order to calculate the level density parameter |
---|
| 79 | // G4EvaporationLevelDensityParameter theLDP; |
---|
| 80 | |
---|
| 81 | // Number of holes |
---|
| 82 | G4double H = aFragment.GetNumberOfHoles(); |
---|
| 83 | // Number of Particles |
---|
| 84 | G4double P = aFragment.GetNumberOfParticles(); |
---|
| 85 | // Number of Excitons |
---|
| 86 | G4double N = P+H; |
---|
| 87 | // Nucleus |
---|
| 88 | G4double A = aFragment.GetA(); |
---|
| 89 | G4double Z = static_cast<G4double>(aFragment.GetZ()); |
---|
| 90 | G4double U = aFragment.GetExcitationEnergy(); |
---|
| 91 | |
---|
[962] | 92 | if(U<10*eV) return 0.0; |
---|
[819] | 93 | |
---|
[962] | 94 | //J. M. Quesada (Feb. 08) new physics |
---|
| 95 | // OPT=1 Transitions are calculated according to Gudima's paper (original in G4PreCompound from VL) |
---|
| 96 | // OPT=2 Transitions are calculated according to Gupta's formulae |
---|
| 97 | // |
---|
| 98 | |
---|
| 99 | |
---|
| 100 | |
---|
| 101 | if (useCEMtr){ |
---|
[819] | 102 | |
---|
[962] | 103 | |
---|
| 104 | // Relative Energy (T_{rel}) |
---|
| 105 | G4double RelativeEnergy = (8.0/5.0)*FermiEnergy + U/N; |
---|
| 106 | |
---|
| 107 | // Sample kind of nucleon-projectile |
---|
| 108 | G4bool ChargedNucleon(false); |
---|
| 109 | G4double chtest = 0.5; |
---|
| 110 | if (P > 0) chtest = aFragment.GetNumberOfCharged()/P; |
---|
| 111 | if (G4UniformRand() < chtest) ChargedNucleon = true; |
---|
| 112 | |
---|
| 113 | // Relative Velocity: |
---|
| 114 | // <V_{rel}>^2 |
---|
| 115 | G4double RelativeVelocitySqr(0.0); |
---|
| 116 | if (ChargedNucleon) RelativeVelocitySqr = 2.0*RelativeEnergy/proton_mass_c2; |
---|
| 117 | else RelativeVelocitySqr = 2.0*RelativeEnergy/neutron_mass_c2; |
---|
| 118 | |
---|
| 119 | // <V_{rel}> |
---|
| 120 | G4double RelativeVelocity = std::sqrt(RelativeVelocitySqr); |
---|
| 121 | |
---|
| 122 | // Proton-Proton Cross Section |
---|
| 123 | G4double ppXSection = (10.63/RelativeVelocitySqr - 29.92/RelativeVelocity + 42.9)*millibarn; |
---|
| 124 | // Proton-Neutron Cross Section |
---|
| 125 | G4double npXSection = (34.10/RelativeVelocitySqr - 82.20/RelativeVelocity + 82.2)*millibarn; |
---|
| 126 | |
---|
| 127 | // Averaged Cross Section: \sigma(V_{rel}) |
---|
| 128 | // G4double AveragedXSection = (ppXSection+npXSection)/2.0; |
---|
| 129 | G4double AveragedXSection(0.0); |
---|
| 130 | if (ChargedNucleon) |
---|
| 131 | { |
---|
| 132 | //JMQ: small bug fixed |
---|
| 133 | // AveragedXSection = ((Z-1.0) * ppXSection + (A-Z-1.0) * npXSection) / (A-1.0); |
---|
| 134 | AveragedXSection = ((Z-1.0) * ppXSection + (A-Z) * npXSection) / (A-1.0); |
---|
| 135 | } |
---|
| 136 | else |
---|
| 137 | { |
---|
| 138 | AveragedXSection = ((A-Z-1.0) * ppXSection + Z * npXSection) / (A-1.0); |
---|
| 139 | } |
---|
| 140 | |
---|
| 141 | // Fermi relative energy ratio |
---|
| 142 | G4double FermiRelRatio = FermiEnergy/RelativeEnergy; |
---|
| 143 | |
---|
| 144 | // This factor is introduced to take into account the Pauli principle |
---|
| 145 | G4double PauliFactor = 1.0 - (7.0/5.0)*FermiRelRatio; |
---|
| 146 | if (FermiRelRatio > 0.5) PauliFactor += (2.0/5.0)*FermiRelRatio*std::pow(2.0 - (1.0/FermiRelRatio), 5.0/2.0); |
---|
| 147 | |
---|
| 148 | // Interaction volume |
---|
| 149 | // G4double Vint = (4.0/3.0)*pi*std::pow(2.0*r0 + hbarc/(proton_mass_c2*RelativeVelocity) , 3.0); |
---|
| 150 | G4double xx=2.0*r0 + hbarc/(proton_mass_c2*RelativeVelocity); |
---|
| 151 | G4double Vint = (4.0/3.0)*pi*xx*xx*xx; |
---|
| 152 | |
---|
| 153 | // Transition probability for \Delta n = +2 |
---|
| 154 | |
---|
| 155 | TransitionProb1 = AveragedXSection*PauliFactor*std::sqrt(2.0*RelativeEnergy/proton_mass_c2)/Vint; |
---|
| 156 | if (TransitionProb1 < 0.0) TransitionProb1 = 0.0; |
---|
| 157 | |
---|
| 158 | G4double a = G4PreCompoundParameters::GetAddress()->GetLevelDensity(); |
---|
| 159 | // GE = g*E where E is Excitation Energy |
---|
| 160 | G4double GE = (6.0/pi2)*a*A*U; |
---|
| 161 | |
---|
| 162 | G4double Fph = ((P*P+H*H+P-H)/4.0 - H/2.0); |
---|
| 163 | |
---|
| 164 | //G4bool NeverGoBack(false); |
---|
| 165 | G4bool NeverGoBack; |
---|
| 166 | if(useNGB) NeverGoBack=true; |
---|
| 167 | else NeverGoBack=false; |
---|
| 168 | |
---|
| 169 | |
---|
| 170 | //JMQ/AH bug fixed: if (U-Fph < 0.0) NeverGoBack = true; |
---|
| 171 | if (GE-Fph < 0.0) NeverGoBack = true; |
---|
| 172 | |
---|
| 173 | // F(p+1,h+1) |
---|
| 174 | G4double Fph1 = Fph + N/2.0; |
---|
| 175 | |
---|
| 176 | G4double ProbFactor = std::pow((GE-Fph)/(GE-Fph1),N+1.0); |
---|
| 177 | |
---|
| 178 | |
---|
| 179 | if (NeverGoBack) |
---|
| 180 | { |
---|
[819] | 181 | TransitionProb2 = 0.0; |
---|
| 182 | TransitionProb3 = 0.0; |
---|
[962] | 183 | } |
---|
| 184 | else |
---|
| 185 | { |
---|
| 186 | // Transition probability for \Delta n = -2 (at F(p,h) = 0) |
---|
| 187 | TransitionProb2 = TransitionProb1 * ProbFactor * (P*H*(N+1.0)*(N-2.0))/((GE-Fph)*(GE-Fph)); |
---|
| 188 | if (TransitionProb2 < 0.0) TransitionProb2 = 0.0; |
---|
| 189 | |
---|
| 190 | // Transition probability for \Delta n = 0 (at F(p,h) = 0) |
---|
| 191 | TransitionProb3 = TransitionProb1* ((N+1.0)/N) * ProbFactor * (P*(P-1.0) + 4.0*P*H + H*(H-1.0))/(GE-Fph); |
---|
| 192 | if (TransitionProb3 < 0.0) TransitionProb3 = 0.0; |
---|
| 193 | } |
---|
| 194 | |
---|
| 195 | // G4cout<<"U = "<<U<<G4endl; |
---|
| 196 | // G4cout<<"N="<<N<<" P="<<P<<" H="<<H<<G4endl; |
---|
| 197 | // G4cout<<"l+ ="<<TransitionProb1<<" l- ="<< TransitionProb2<<" l0 ="<< TransitionProb3<<G4endl; |
---|
| 198 | return TransitionProb1 + TransitionProb2 + TransitionProb3; |
---|
| 199 | } |
---|
| 200 | |
---|
| 201 | else { |
---|
| 202 | //JMQ: Transition probabilities from Gupta's work |
---|
| 203 | |
---|
| 204 | G4double a = G4PreCompoundParameters::GetAddress()->GetLevelDensity(); |
---|
| 205 | // GE = g*E where E is Excitation Energy |
---|
| 206 | G4double GE = (6.0/pi2)*a*A*U; |
---|
| 207 | |
---|
| 208 | G4double Kmfp=2.; |
---|
| 209 | |
---|
| 210 | |
---|
| 211 | TransitionProb1=1./Kmfp*3./8.*1./c_light*1.0e-9*(1.4e+21*U-2./(N+1)*6.0e+18*U*U); |
---|
| 212 | if (TransitionProb1 < 0.0) TransitionProb1 = 0.0; |
---|
| 213 | |
---|
| 214 | if (useNGB){ |
---|
| 215 | TransitionProb2=0.; |
---|
| 216 | TransitionProb3=0.; |
---|
[819] | 217 | } |
---|
[962] | 218 | else{ |
---|
| 219 | if (N<=1) TransitionProb2=0. ; |
---|
| 220 | 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); |
---|
[819] | 221 | if (TransitionProb2 < 0.0) TransitionProb2 = 0.0; |
---|
[962] | 222 | TransitionProb3=0.; |
---|
[819] | 223 | } |
---|
[962] | 224 | |
---|
| 225 | // G4cout<<"U = "<<U<<G4endl; |
---|
| 226 | // G4cout<<"N="<<N<<" P="<<P<<" H="<<H<<G4endl; |
---|
| 227 | // G4cout<<"l+ ="<<TransitionProb1<<" l- ="<< TransitionProb2<<" l0 ="<< TransitionProb3<<G4endl; |
---|
| 228 | return TransitionProb1 + TransitionProb2 + TransitionProb3; |
---|
| 229 | } |
---|
[819] | 230 | } |
---|
| 231 | |
---|
| 232 | |
---|
| 233 | G4Fragment G4PreCompoundTransitions::PerformTransition(const G4Fragment & aFragment) |
---|
| 234 | { |
---|
| 235 | G4Fragment result(aFragment); |
---|
| 236 | G4double ChosenTransition = G4UniformRand()*(TransitionProb1 + TransitionProb2 + TransitionProb3); |
---|
| 237 | G4int deltaN = 0; |
---|
| 238 | G4int Nexcitons = result.GetNumberOfExcitons(); |
---|
| 239 | if (ChosenTransition <= TransitionProb1) |
---|
| 240 | { |
---|
| 241 | // Number of excitons is increased on \Delta n = +2 |
---|
| 242 | deltaN = 2; |
---|
| 243 | } |
---|
| 244 | else if (ChosenTransition <= TransitionProb1+TransitionProb2) |
---|
| 245 | { |
---|
| 246 | // Number of excitons is increased on \Delta n = -2 |
---|
| 247 | deltaN = -2; |
---|
| 248 | } |
---|
| 249 | |
---|
[962] | 250 | // AH/JMQ: Randomly decrease the number of charges if deltaN is -2 and in proportion |
---|
| 251 | // to the number charges w.r.t. number of particles, PROVIDED that there are charged particles |
---|
| 252 | if(deltaN < 0 && G4UniformRand() <= |
---|
| 253 | static_cast<G4double>(result.GetNumberOfCharged())/static_cast<G4double>(result.GetNumberOfParticles()) |
---|
| 254 | && (result.GetNumberOfCharged() >= 1)) { |
---|
[819] | 255 | result.SetNumberOfCharged(result.GetNumberOfCharged()+deltaN/2); // deltaN is negative! |
---|
[962] | 256 | } |
---|
[819] | 257 | |
---|
[962] | 258 | // JMQ the following lines have to be before SetNumberOfCharged, otherwise the check on |
---|
| 259 | // number of charged vs. number of particles fails |
---|
[819] | 260 | result.SetNumberOfParticles(result.GetNumberOfParticles()+deltaN/2); |
---|
| 261 | result.SetNumberOfHoles(result.GetNumberOfHoles()+deltaN/2); |
---|
| 262 | |
---|
[962] | 263 | // With weight Z/A, number of charged particles is increased with +1 |
---|
[819] | 264 | if ( ( deltaN > 0 ) && |
---|
| 265 | (G4UniformRand() <= static_cast<G4double>(result.GetZ()-result.GetNumberOfCharged())/ |
---|
[962] | 266 | std::max(static_cast<G4double>(result.GetA()-Nexcitons),1.))) |
---|
[819] | 267 | { |
---|
| 268 | result.SetNumberOfCharged(result.GetNumberOfCharged()+deltaN/2); |
---|
| 269 | } |
---|
| 270 | |
---|
| 271 | // Number of charged can not be greater that number of particles |
---|
| 272 | if ( result.GetNumberOfParticles() < result.GetNumberOfCharged() ) |
---|
| 273 | { |
---|
| 274 | result.SetNumberOfCharged(result.GetNumberOfParticles()); |
---|
| 275 | } |
---|
| 276 | |
---|
| 277 | return result; |
---|
| 278 | } |
---|
| 279 | |
---|