Gabriele Cosmo
72 lines
2.8 KiB
C++
72 lines
2.8 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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//
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#ifndef G4NuclearFermiDensity_h
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#define G4NuclearFermiDensity_h 1
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#include "globals.hh"
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#include "G4ThreeVector.hh"
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#include "G4VNuclearDensity.hh"
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#include <CLHEP/Units/PhysicalConstants.h> // pi, fermi,..
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#include "G4Exp.hh"
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#include "G4Log.hh"
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//#include <cmath> // pow
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class G4NuclearFermiDensity : public G4VNuclearDensity
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{
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public:
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G4NuclearFermiDensity(G4int anA, G4int aZ);
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~G4NuclearFermiDensity();
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G4double GetRelativeDensity(const G4ThreeVector & aPosition) const
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{
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return 1./(1.+G4Exp((aPosition.mag()-theR)/a));
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}
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G4double GetRadius(const G4double maxRelativeDenisty) const
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{
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return (maxRelativeDenisty>0 && maxRelativeDenisty <= 1 ) ?
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(theR + a*G4Log((1-maxRelativeDenisty+G4Exp(-1*theR/a))/maxRelativeDenisty)) : DBL_MAX;
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}
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G4double GetDeriv(const G4ThreeVector & aPosition) const
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{
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G4double currentR=aPosition.mag();
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if (currentR > 40*theR ) {return 0;}
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else return -G4Exp((currentR-theR)/a) * sqr(GetDensity(aPosition)) / (a*Getrho0());
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}
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private:
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G4int theA;
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G4double theR; // Nuclear Radius
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const G4double a; // Determines the nuclear surface thickness
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};
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#endif
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