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G4NuclearFermiDensity.hh
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27 
28 #ifndef G4NuclearFermiDensity_h
29 #define G4NuclearFermiDensity_h 1
30 
31 #include "globals.hh"
32 #include "G4ThreeVector.hh"
33 #include "G4VNuclearDensity.hh"
34 
35 #include <CLHEP/Units/PhysicalConstants.h> // pi, fermi,..
36 #include "G4Exp.hh"
37 #include "G4Log.hh"
38 //#include <cmath> // pow
39 
41 {
42  public:
45 
46  G4double GetRelativeDensity(const G4ThreeVector & aPosition) const
47  {
48  return 1./(1.+G4Exp((aPosition.mag()-theR)/a));
49  }
50 
51  G4double GetRadius(const G4double maxRelativeDenisty) const
52  {
53  return (maxRelativeDenisty>0 && maxRelativeDenisty <= 1 ) ?
54  (theR + a*G4Log((1-maxRelativeDenisty+G4Exp(-1*theR/a))/maxRelativeDenisty)) : DBL_MAX;
55  }
56 
57  G4double GetDeriv(const G4ThreeVector & aPosition) const
58  {
59  G4double currentR=aPosition.mag();
60  if (currentR > 40*theR ) {return 0;}
61  else return -G4Exp((currentR-theR)/a) * sqr(GetDensity(aPosition)) / (a*Getrho0());
62  }
63 
64  private:
66  G4double theR; // Nuclear Radius
67  const G4double a; // Determines the nuclear surface thickness
68 };
69 
70 #endif
71