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