Gabriele Cosmo
111 lines
4.3 KiB
C++
111 lines
4.3 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// By JPW, working, but to be cleaned up. @@@
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// G.Folger, 29-sept-2006: extend to 1TeV, using a constant above 20GeV
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// 22 Dec 2006 - DHW added isotope dependence
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// G.Folger, 25-Nov-2009: extend to 100TeV, using a constant above 20GeV
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// V.Ivanchenko, 18-Aug-2011: migration to new design and cleanup;
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// make it applicable for Z>1
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//
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#include "G4ProtonInelasticCrossSection.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4DynamicParticle.hh"
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#include "G4Proton.hh"
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#include "G4HadTmpUtil.hh"
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#include "G4NistManager.hh"
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G4ProtonInelasticCrossSection::G4ProtonInelasticCrossSection()
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: G4VCrossSectionDataSet("Axen-Wellisch"),thEnergy(19.8*CLHEP::GeV)
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{
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nist = G4NistManager::Instance();
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theProton = G4Proton::Proton();
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}
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G4ProtonInelasticCrossSection::~G4ProtonInelasticCrossSection()
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{}
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G4bool
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G4ProtonInelasticCrossSection::IsElementApplicable(
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const G4DynamicParticle* aPart,
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G4int Z, const G4Material*)
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{
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return ((1 < Z) && (aPart->GetDefinition() == theProton));
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}
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G4double G4ProtonInelasticCrossSection::GetElementCrossSection(
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const G4DynamicParticle* aPart,
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G4int Z, const G4Material*)
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{
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return GetProtonCrossSection(aPart->GetKineticEnergy(), Z);
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}
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G4double G4ProtonInelasticCrossSection::GetProtonCrossSection(
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G4double kineticEnergy, G4int Z)
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{
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if(kineticEnergy <= 0.0) { return 0.0; }
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// constant cross section above ~20GeV
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if (kineticEnergy > thEnergy) { kineticEnergy = thEnergy; }
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G4double a = nist->GetAtomicMassAmu(Z);
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G4double a13 = G4Pow::GetInstance()->powA(a,-0.3333333333);
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G4int nOfNeutrons = G4lrint(a) - Z;
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kineticEnergy /=GeV;
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G4double alog10E = std::log10(kineticEnergy);
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static const G4double nuleonRadius=1.36e-15;
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static const G4double fac=CLHEP::pi*nuleonRadius*nuleonRadius;
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G4double b0 = 2.247-0.915*(1 - a13);
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G4double fac1 = b0*(1 - a13);
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G4double fac2 = 1.;
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if(nOfNeutrons > 1) { fac2=G4Log((G4double(nOfNeutrons))); }
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G4double crossSection = 1.0E31*fac*fac2*(1. + 1./a13 - fac1);
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// high energy correction
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crossSection *= (1 - 0.15*G4Exp(-kineticEnergy))/(1.0 - 0.0007*a);
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// first try on low energies: rise
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G4double ff1= 0.70-0.002*a; // slope of the drop at medium energies.
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G4double ff2= 1.00+1/a; // start of the slope.
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G4double ff3= 0.8+18/a-0.002*a; // stephight
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G4double ff4= 1.0 - (1.0/(1+G4Exp(-8*ff1*(alog10E + 1.37*ff2))));
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crossSection *= (1 + ff3*ff4);
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// low energy return to zero
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ff1=1. - 1./a - 0.001*a; // slope of the rise
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ff2=1.17 - 2.7/a - 0.0014*a; // start of the rise
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ff4=-8.*ff1*(alog10E + 2.0*ff2);
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crossSection *= millibarn/(1. + G4Exp(ff4));
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return crossSection;
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}
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