[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 | // By JPW, working, but to be cleaned up. @@@ |
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| 27 | // 22 Dec 2006 - DHW added isotope dependence |
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[1228] | 28 | // G.Folger, 25-Nov-2009: extend to 100TeV, using a constant above 20GeV |
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[819] | 29 | // |
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| 30 | |
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| 31 | #include "G4NeutronInelasticCrossSection.hh" |
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| 32 | #include "globals.hh" |
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| 33 | |
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| 34 | G4double G4NeutronInelasticCrossSection:: |
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| 35 | GetCrossSection(const G4DynamicParticle* aPart, |
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| 36 | const G4Element* anEle, G4double /*aTemperature*/) |
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| 37 | { |
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| 38 | G4int nIso = anEle->GetNumberOfIsotopes(); |
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| 39 | G4double KE = aPart->GetKineticEnergy(); |
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| 40 | G4double cross_section = 0; |
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| 41 | |
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| 42 | if (nIso) { |
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| 43 | G4double psig; |
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| 44 | G4IsotopeVector* isoVector = anEle->GetIsotopeVector(); |
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| 45 | G4double* abundVector = anEle->GetRelativeAbundanceVector(); |
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| 46 | G4double ZZ; |
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| 47 | G4double AA; |
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| 48 | |
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| 49 | for (G4int i = 0; i < nIso; i++) { |
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| 50 | ZZ = G4double( (*isoVector)[i]->GetZ() ); |
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| 51 | AA = G4double( (*isoVector)[i]->GetN() ); |
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| 52 | psig = GetCrossSection(KE, AA, ZZ); |
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| 53 | cross_section += psig*abundVector[i]; |
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| 54 | } |
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| 55 | |
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| 56 | } else { |
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| 57 | cross_section = GetCrossSection(KE, anEle->GetN(), anEle->GetZ()); |
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| 58 | } |
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| 59 | |
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| 60 | return cross_section; |
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| 61 | } |
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| 62 | |
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| 63 | |
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| 64 | G4double G4NeutronInelasticCrossSection:: |
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| 65 | GetCrossSection(G4double anEnergy, G4double atomicNumber, G4double nOfProtons) |
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| 66 | { |
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[1228] | 67 | if (anEnergy > 19.9*GeV ) |
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| 68 | { // constant cross section above ~20GeV. |
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| 69 | return GetCrossSection(19.8*GeV,atomicNumber,nOfProtons); |
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| 70 | } |
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[819] | 71 | G4double kineticEnergy = std::log10(DBL_MIN/MeV); |
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| 72 | if (anEnergy > DBL_MIN/MeV) kineticEnergy = std::log10(anEnergy/MeV); |
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| 73 | G4double nOfNeutrons = atomicNumber-nOfProtons; |
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| 74 | const G4double p1=1.3773; |
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| 75 | const G4double p2=1.+10./atomicNumber-0.0006*atomicNumber; |
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| 76 | const G4double p3=0.6+13./atomicNumber-0.0005*atomicNumber; |
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| 77 | const G4double p4=7.2449-0.018242*atomicNumber; |
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| 78 | const G4double p5=1.64-1.8/atomicNumber-0.0005*atomicNumber; |
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| 79 | const G4double p6=1.+200./atomicNumber+0.02*atomicNumber; |
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| 80 | const G4double p7=(atomicNumber-70.)*(atomicNumber-200.)/11000.; |
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| 81 | |
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| 82 | G4double logN = 1.0; |
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| 83 | if (nOfNeutrons > 1.5) logN = std::log(nOfNeutrons); |
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| 84 | G4double part1 = pi*(p1*p1)*logN; |
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| 85 | G4double part2 = 1.+ std::pow(atomicNumber, 1./3.) |
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| 86 | - p2*(1.-1./std::pow(atomicNumber, 1./3.)); |
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| 87 | |
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| 88 | G4double firstexp = -p4*(kineticEnergy-p5); |
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| 89 | G4double first=1.+std::exp(firstexp); |
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| 90 | G4double corr = 1.+p3*(1.-1./first); |
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| 91 | |
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| 92 | G4double secondexp = -p6*(kineticEnergy-p7); |
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| 93 | G4double second=1.+std::exp(secondexp); |
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| 94 | G4double corr2 =1./second; |
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| 95 | |
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| 96 | G4double xsec = corr*corr2*part1*part2*10.*millibarn; |
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| 97 | return xsec; |
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| 98 | } |
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