| 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 | //
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| 27 | //
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| 28 | #ifndef G4NuclearFermiDensity_h
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| 29 | #define G4NuclearFermiDensity_h 1
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| 30 |
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| 31 | #include "globals.hh"
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| 32 | #include "G4ThreeVector.hh"
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| 33 | #include "G4VNuclearDensity.hh"
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| 34 |
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| 35 | #include <CLHEP/Units/PhysicalConstants.h> // pi, fermi,..
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| 36 | #include <cmath> // pow
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| 37 |
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| 38 | class G4NuclearFermiDensity : public G4VNuclearDensity
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| 39 | {
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| 40 |
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| 41 | public:
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| 42 | G4NuclearFermiDensity(G4double anA, G4double aZ);
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| 43 | ~G4NuclearFermiDensity();
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| 44 |
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| 45 | G4double GetRelativeDensity(const G4ThreeVector & aPosition) const
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| 46 | {
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| 47 | return 1./(1.+std::exp((aPosition.mag()-theR)/a));
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| 48 | }
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| 49 |
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| 50 | G4double GetRadius(const G4double maxRelativeDenisty) const
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| 51 | {
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| 52 | return (maxRelativeDenisty>0 && maxRelativeDenisty <= 1 ) ?
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| 53 | (theR + a*std::log((1-maxRelativeDenisty+std::exp(-1*theR/a))/maxRelativeDenisty)) : DBL_MAX;
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| 54 | }
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| 55 |
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| 56 | G4double GetDeriv(const G4ThreeVector & aPosition) const
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| 57 | {
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| 58 | return -std::exp((aPosition.mag()-theR)/a) * sqr(GetDensity(aPosition)) / (a*Getrho0());
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| 59 | }
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| 60 |
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| 61 | private:
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| 62 |
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| 63 | G4int theA;
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| 64 | G4int theZ;
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| 65 | G4double theR; // Nuclear Radius
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| 66 | const G4double a; // Determines the nuclear surface thickness
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| 67 |
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| 68 | };
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| 69 |
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| 70 | #endif
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| 71 |
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