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 | // By JPW, working, but to be cleaned up. @@@ |
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27 | // G.Folger, 29-sept-2006: extend to 1TeV, using a constant above 20GeV |
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28 | // 22 Dec 2006 - DHW added isotope dependence |
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29 | // G.Folger, 25-Nov-2009: extend to 100TeV, using a constant above 20GeV |
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30 | // |
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31 | |
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32 | #include "G4ProtonInelasticCrossSection.hh" |
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33 | #include "globals.hh" |
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34 | |
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35 | |
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36 | G4double G4ProtonInelasticCrossSection:: |
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37 | GetCrossSection(const G4DynamicParticle* aPart, |
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38 | const G4Element* anEle, G4double /*aTemperature*/) |
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39 | { |
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40 | G4int nIso = anEle->GetNumberOfIsotopes(); |
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41 | G4double KE = aPart->GetKineticEnergy(); |
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42 | G4double cross_section = 0; |
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43 | |
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44 | if (nIso) { |
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45 | G4double psig; |
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46 | G4IsotopeVector* isoVector = anEle->GetIsotopeVector(); |
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47 | G4double* abundVector = anEle->GetRelativeAbundanceVector(); |
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48 | G4double ZZ; |
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49 | G4double AA; |
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50 | |
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51 | for (G4int i = 0; i < nIso; i++) { |
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52 | ZZ = G4double( (*isoVector)[i]->GetZ() ); |
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53 | AA = G4double( (*isoVector)[i]->GetN() ); |
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54 | psig = GetCrossSection(KE, AA, ZZ); |
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55 | cross_section += psig*abundVector[i]; |
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56 | } |
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57 | |
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58 | } else { |
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59 | cross_section = GetCrossSection(KE, anEle->GetN(), anEle->GetZ()); |
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60 | } |
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61 | |
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62 | return cross_section; |
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63 | } |
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64 | |
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65 | |
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66 | G4double G4ProtonInelasticCrossSection:: |
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67 | GetCrossSection(G4double kineticEnergy, G4double atomicNumber, G4double nOfProtons) |
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68 | { |
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69 | if (kineticEnergy > 19.9*GeV ) |
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70 | { // constant cross section above ~20GeV. |
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71 | return GetCrossSection(19.8*GeV,atomicNumber,nOfProtons); |
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72 | } |
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73 | G4double nOfNeutrons = atomicNumber-nOfProtons; |
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74 | kineticEnergy /=GeV; |
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75 | G4double a = atomicNumber; |
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76 | const G4double nuleonRadius=1.36E-15; |
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77 | const G4double pi=3.14159265; |
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78 | G4double fac=pi*nuleonRadius*nuleonRadius; |
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79 | G4double b0=2.247-0.915*(1-std::pow(a,-0.3333)); |
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80 | G4double fac1=b0*(1-std::pow(a,-0.3333)); |
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81 | G4double fac2=1.; |
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82 | if(nOfNeutrons>1.5) fac2=std::log((nOfNeutrons)); |
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83 | G4double crossSection = 1E31*fac*fac2*(1+std::pow(a,0.3333)-fac1); |
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84 | |
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85 | // high energy correction |
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86 | |
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87 | crossSection = (1-0.15*std::exp(-kineticEnergy))*crossSection/(1.00-0.0007*a); |
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88 | // first try on low energies: rise |
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89 | |
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90 | G4double ff1= 0.70-0.002*a; // slope of the drop at medium energies. |
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91 | G4double ff2= 1.00+1/a; // start of the slope. |
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92 | G4double ff3= 0.8+18/a-0.002*a; // stephight |
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93 | fac = 1.0; |
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94 | if (kineticEnergy > DBL_MIN) |
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95 | fac= 1.0 - (1.0/(1+std::exp(-8*ff1*(std::log10(kineticEnergy)+1.37*ff2)))); |
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96 | crossSection = crossSection*(1+ff3*fac); |
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97 | |
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98 | // low energy return to zero |
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99 | |
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100 | ff1=1.-1/a-0.001*a; // slope of the rise |
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101 | ff2=1.17-2.7/a-0.0014*a; // start of the rise |
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102 | fac = 0.0; |
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103 | if (kineticEnergy > DBL_MIN) { |
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104 | fac=-8.*ff1*(std::log10(kineticEnergy)+2.0*ff2); |
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105 | fac=1/(1+std::exp(fac)); |
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106 | } |
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107 | crossSection = crossSection*fac; |
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108 | return crossSection*millibarn; |
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109 | } |
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