Geant4  9.6.p02
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G4FissionProbability.cc
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27 // $Id$
28 //
29 // Hadronic Process: Nuclear De-excitations
30 // by V. Lara (Oct 1998)
31 //
32 //
33 // J.M.Quesada (14 february 2009) bug fixed in fission width: missing parenthesis in the denominator
34 
35 
36 #include "G4FissionProbability.hh"
37 #include "G4PhysicalConstants.hh"
38 #include "G4PairingCorrection.hh"
39 
41 {}
42 
44 {}
45 
46 
47 G4double
49  G4double MaximalKineticEnergy)
50  // Compute integrated probability of fission channel
51 {
52  if (MaximalKineticEnergy <= 0.0) return 0.0;
53  G4int A = fragment.GetA_asInt();
54  G4int Z = fragment.GetZ_asInt();
55  G4double U = fragment.GetExcitationEnergy();
56 
57  G4double Ucompound = U -
59 
60  G4double Ufission = U -
62 
63  G4double SystemEntropy =
64  2.0*std::sqrt(theEvapLDP.LevelDensityParameter(A,Z,Ucompound)*Ucompound);
65 
66  G4double afission = theFissLDP.LevelDensityParameter(A,Z,Ufission);
67 
68  G4double Cf = 2.0*std::sqrt(afission*MaximalKineticEnergy);
69 
70  // G4double Q1 = 1.0 + (Cf - 1.0)*std::exp(Cf);
71  // G4double Q2 = 4.0*pi*afission*std::exp(SystemEntropy);
72 
73  // G4double probability = Q1/Q2;
74 
75  G4double Exp1 = 0.0;
76  if (SystemEntropy <= 160.0) { Exp1 = std::exp(-SystemEntropy); }
77  // @@@@@@@@@@@@@@@@@ hpw changed max to min - cannot notify vicente now
78  G4double Exp2 = std::exp( std::min(700.0,Cf-SystemEntropy) );
79 
80  // JMQ 14/02/09 BUG fixed in fission probability (missing parenthesis
81  // at denominator)
82  //AH fix from Vincente: G4double probability =
83  // (Exp1 + (1.0-Cf)*Exp2) / 4.0*pi*afission;
84  // G4double probability = (Exp1 + (Cf-1.0)*Exp2) / 4.0*pi*afission;
85  G4double probability = (Exp1 + (Cf-1.0)*Exp2) / (4.0*pi*afission);
86 
87  return probability;
88 }
89