Geant4  10.03.p02
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G4FissionParameters.cc
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27 // $Id: G4FissionParameters.cc 89550 2015-04-17 08:38:15Z gcosmo $
28 //
29 // Hadronic Process: Nuclear De-excitations
30 // by V. Lara (Oct 1998)
31 //
32 //J. M. Quesada (May 2009): sigma_sym (SigmaS) tuned for spallation data.
33 //J. M. Quesada (30.10.09): retuning for IAEA spallation data
34 
35 #include "G4FissionParameters.hh"
36 #include "G4SystemOfUnits.hh"
37 #include "G4Exp.hh"
38 
40  : A1(134),A2(141),A3((A1 + A2)*0.5),As(0.0),Sigma1(0.0),Sigma2(0.0),
41  SigmaS(0.),w(0.0)
42 {}
43 
45 {}
46 
48  G4double FissionBarrier)
49 {
50  // to avoid usage of units
51  G4double U = ExEnergy/CLHEP::MeV;
52 
53  As = A*0.5;
54 
55  if (A <= 235) { Sigma2 = 5.6; }
56  else { Sigma2 = 5.6 + 0.096*(A-235); }
57 
58  Sigma1 = 0.5*Sigma2;
59 
60  //JMQ 310509
61  // if (SigmaS > 20.0) SigmaS = 20.0;
62  // SigmaS*=1.3;
63  //JMQ 301009: retuning (after CEM transition prob.have been chosen as default)
64  SigmaS = 0.8*G4Exp(0.00553*U + 2.1386);
65 
66  G4double x1 = (A1-As)/Sigma1;
67  G4double x2 = (A2-As)/Sigma2;
68  G4double FasymAsym = 2*G4Exp(-0.5*x2*x2) + G4Exp(-0.5*x1*x1);
69 
70  G4double x3 = (As-A3)/SigmaS;
71  G4double FsymA1A2 = G4Exp(-0.5*x3*x3);
72 
73  G4double wa = 0.0;
74  w = 0.0;
75  if (Z >= 90) {
76  if (U <= 16.25) { wa = G4Exp(0.5385*U-9.9564); }
77  else { wa = G4Exp(0.09197*U-2.7003); }
78  } else if (Z == 89) {
79  wa = G4Exp(0.09197*U-1.0808);
80  } else if (Z >= 82) {
81  G4double X = std::max(0.0, FissionBarrier/CLHEP::MeV - 7.5);
82  wa = G4Exp(0.09197*(U-X) - 1.0808);
83  } else { // Z < 82
84  w = 1001.0;
85  }
86 
87  if (w == 0.0) {
88  G4double w1 = std::max(1.03*wa - FasymAsym, 0.0001);
89  G4double w2 = std::max(1.0 - FsymA1A2*wa, 0.0001);
90 
91  w = w1/w2;
92 
93  if (82 <= Z && Z < 89 && A < 227) { w *= G4Exp(0.3*(227-A)); }
94  }
95 }
96 
97 
int G4int
Definition: G4Types.hh:78
double A(double temperature)
static constexpr double MeV
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:183
T max(const T t1, const T t2)
brief Return the largest of the two arguments
double G4double
Definition: G4Types.hh:76
void DefineParameters(G4int A, G4int Z, G4double ExEnergy, G4double FissionBarrier)