Geant4  10.02.p02
G4FissionProbability.cc
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27 // $Id: G4FissionProbability.cc 91834 2015-08-07 07:24:22Z gcosmo $
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"
41 #include "G4Exp.hh"
42 
44  theEvapLDP(new G4EvaporationLevelDensityParameter),
45  theFissLDP(new G4FissionLevelDensityParameter),
46  ownEvapLDP(true),
47  ownFissLDP(true)
48 {}
49 
51 {
52  if (ownEvapLDP) delete theEvapLDP;
53  if (ownFissLDP) delete theFissLDP;
54 }
55 
56 
57 G4double
59  G4double MaximalKineticEnergy)
60  // Compute integrated probability of fission channel
61 {
62  if (MaximalKineticEnergy <= 0.0) return 0.0;
63  G4int A = fragment.GetA_asInt();
64  G4int Z = fragment.GetZ_asInt();
65  G4double U = fragment.GetExcitationEnergy();
66 
67  G4double Ucompound = U -
69 
70  G4double Ufission = U -
72 
73  G4double SystemEntropy =
74  2.0*std::sqrt(theEvapLDP->LevelDensityParameter(A,Z,Ucompound)*Ucompound);
75 
76  G4double afission = theFissLDP->LevelDensityParameter(A,Z,Ufission);
77 
78  G4double Cf = 2.0*std::sqrt(afission*MaximalKineticEnergy);
79 
80  // G4double Q1 = 1.0 + (Cf - 1.0)*G4Exp(Cf);
81  // G4double Q2 = 4.0*pi*afission*G4Exp(SystemEntropy);
82 
83  // G4double probability = Q1/Q2;
84 
85  G4double Exp1 = 0.0;
86  if (SystemEntropy <= 160.0) { Exp1 = G4Exp(-SystemEntropy); }
87  // @@@@@@@@@@@@@@@@@ hpw changed max to min - cannot notify vicente now
88  G4double Exp2 = G4Exp( std::min(300.0,Cf-SystemEntropy) );
89 
90  // JMQ 14/02/09 BUG fixed in fission probability (missing parenthesis
91  // at denominator)
92  //AH fix from Vincente: G4double probability =
93  // (Exp1 + (1.0-Cf)*Exp2) / 4.0*pi*afission;
94  // G4double probability = (Exp1 + (Cf-1.0)*Exp2) / 4.0*pi*afission;
95  G4double probability = (Exp1 + (Cf-1.0)*Exp2) / (4.0*pi*afission);
96 
97  return probability;
98 }
99 
G4double EmissionProbability(const G4Fragment &fragment, G4double MaximalKineticEnergy)
int G4int
Definition: G4Types.hh:78
double A(double temperature)
G4int GetA_asInt() const
Definition: G4Fragment.hh:256
G4double GetPairingCorrection(G4int A, G4int Z) const
G4double G4Exp(G4double initial_x)
Exponential Function double precision.
Definition: G4Exp.hh:183
static G4PairingCorrection * GetInstance()
G4double GetFissionPairingCorrection(G4int A, G4int Z) const
static const double pi
Definition: G4SIunits.hh:74
G4VLevelDensityParameter * theEvapLDP
virtual G4double LevelDensityParameter(G4int A, G4int Z, G4double U) const =0
T min(const T t1, const T t2)
brief Return the smallest of the two arguments
G4int GetZ_asInt() const
Definition: G4Fragment.hh:261
double G4double
Definition: G4Types.hh:76
G4double GetExcitationEnergy() const
Definition: G4Fragment.hh:273
G4VLevelDensityParameter * theFissLDP