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G4FissionBarrier.cc
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25 //
26 //
27 // Hadronic Process: Nuclear De-excitations
28 // by V. Lara (Oct 1998)
29 //
30 // 17.11.2010 V.Ivanchenko cleanup and add usage of G4Pow
31 // 21.03.2013 V.Ivanchenko redesign parameters classes
32 
33 #include "G4FissionBarrier.hh"
35 #include "G4NuclearLevelData.hh"
36 #include "G4ShellCorrection.hh"
37 #include "G4SystemOfUnits.hh"
38 #include "G4Pow.hh"
39 
41 {
44 }
45 
47 {}
48 
49 G4double
51  // Compute fission barrier according with Barashenkov's
52  // prescription for A >= 65
53 {
54  static const G4double blimit = 100.0*CLHEP::GeV;
55  return (A >= 65) ? BarashenkovFissionBarrier(A,Z)
56  /(1.0 + std::sqrt(U/(G4double)(2*A))) : blimit;
57 }
58 
59 G4double
61  // Calculates Fission Barrier heights
62 {
63  // Liquid drop model parameters for
64  // surface energy of a spherical nucleus
65  static const G4double aSurf = 17.9439*CLHEP::MeV;
66  // and coulomb energy
67  static const G4double aCoul = 0.7053*CLHEP::MeV;
68  static const G4double k = 1.7826;
69  G4int N = A - Z;
70 
71  // fissibility parameter
72  G4double x = (aCoul/(2.0*aSurf))*(Z*Z)/static_cast<G4double>(A);
73  x /= (1.0 - k*(N-Z)*(N-Z)/static_cast<G4double>(A*A));
74 
75  // Liquid drop model part of Fission Barrier
76  G4double BF0 = aSurf*G4Pow::GetInstance()->Z23(A);
77  if (x <= 2./3.) { BF0 *= 0.38*(0.75 - x); }
78  else { BF0 *= 0.83*(1. - x)*(1. - x)*(1. - x); }
79 
80  G4int d = N - 2*(N/2) + Z - 2*(Z/2);
81 
82  G4double res = 0.0;
83  SPtr->GetPairingCorrection(N,Z,res);
84 
85  static const G4double D = 1.248*CLHEP::MeV;
86  return BF0 + D*d - res;
87 }
88