source: trunk/source/processes/hadronic/models/de_excitation/evaporation/src/G4EvaporationProbability.cc @ 1198

Last change on this file since 1198 was 1055, checked in by garnier, 15 years ago

maj sur la beta de geant 4.9.3
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25//
26//J.M. Quesada (August2008). Based on:
27//
28// Hadronic Process: Nuclear De-excitations
29// by V. Lara (Oct 1998)
30//
31// Modif (03 September 2008) by J. M. Quesada for external choice of inverse
32// cross section option
33// JMQ (06 September 2008) Also external choices have been added for
34// superimposed Coulomb barrier (if useSICB is set true, by default is false)
35//
36// JMQ (14 february 2009) bug fixed in emission width: hbarc instead of hbar_Planck in the denominator
37//
38#include <iostream>
39using namespace std;
40
41#include "G4EvaporationProbability.hh"
42#include "G4PairingCorrection.hh"
43
44
45
46G4EvaporationProbability::G4EvaporationProbability(const G4EvaporationProbability &) : G4VEmissionProbability()
47{
48    throw G4HadronicException(__FILE__, __LINE__, "G4EvaporationProbability::copy_constructor meant to not be accessable");
49}
50
51
52
53
54const G4EvaporationProbability & G4EvaporationProbability::
55operator=(const G4EvaporationProbability &)
56{
57    throw G4HadronicException(__FILE__, __LINE__, "G4EvaporationProbability::operator= meant to not be accessable");
58    return *this;
59}
60
61
62G4bool G4EvaporationProbability::operator==(const G4EvaporationProbability &) const
63{
64    return false;
65}
66
67G4bool G4EvaporationProbability::operator!=(const G4EvaporationProbability &) const
68{
69    return true;
70}
71 
72G4double G4EvaporationProbability::EmissionProbability(const G4Fragment & fragment, const G4double anEnergy)
73{
74    G4double EmissionProbability = 0.0;
75    G4double MaximalKineticEnergy = anEnergy;
76
77    if (MaximalKineticEnergy > 0.0 && fragment.GetExcitationEnergy() > 0.0) {
78        EmissionProbability = CalculateProbability(fragment, MaximalKineticEnergy);
79
80    }
81    return EmissionProbability;
82}
83
84////////////////////////////////////
85
86// Computes the integrated probability of evaporation channel
87G4double G4EvaporationProbability::CalculateProbability(const G4Fragment & fragment, const G4double MaximalKineticEnergy)
88{
89    G4double ResidualA = fragment.GetA() - theA;
90    G4double ResidualZ = fragment.GetZ() - theZ;
91    G4double U = fragment.GetExcitationEnergy();
92   
93 if (OPTxs==0) {
94
95       
96    G4double NuclearMass = G4ParticleTable::GetParticleTable()->GetIonTable()->GetNucleusMass(theZ,theA);
97
98
99    G4double delta0 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(fragment.GetA()),
100                                                                               static_cast<G4int>(fragment.GetZ()));
101
102    G4double SystemEntropy = 2.0*std::sqrt(theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(fragment.GetA()),
103                                                                           static_cast<G4int>(fragment.GetZ()),U)*
104                                      (U-delta0));
105                                                                 
106
107    G4double RN = 1.5*fermi;
108
109    G4double Alpha = CalcAlphaParam(fragment);
110    G4double Beta = CalcBetaParam(fragment);
111       
112    G4double Rmax = MaximalKineticEnergy;
113    G4double a = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(ResidualA),
114                                                      static_cast<G4int>(ResidualZ),
115                                                      Rmax);
116    G4double GlobalFactor = static_cast<G4double>(Gamma) * (Alpha/(a*a)) *
117        (NuclearMass*RN*RN*std::pow(ResidualA,2./3.))/
118        (2.*pi* hbar_Planck*hbar_Planck);
119    G4double Term1 = (2.0*Beta*a-3.0)/2.0 + Rmax*a;
120    G4double Term2 = (2.0*Beta*a-3.0)*std::sqrt(Rmax*a) + 2.0*a*Rmax;
121       
122    G4double ExpTerm1 = 0.0;
123    if (SystemEntropy <= 600.0) ExpTerm1 = std::exp(-SystemEntropy);
124       
125    G4double ExpTerm2 = 2.*std::sqrt(a*Rmax) - SystemEntropy;
126    if (ExpTerm2 > 700.0) ExpTerm2 = 700.0;
127    ExpTerm2 = std::exp(ExpTerm2);
128       
129    G4double Width = GlobalFactor*(Term1*ExpTerm1 + Term2*ExpTerm2);
130       
131    return Width;
132             
133 } else if (OPTxs==1 || OPTxs==2 ||OPTxs==3 || OPTxs==4) {
134
135   G4double limit;
136   if (useSICB) limit=theCoulombBarrierptr->GetCoulombBarrier(G4lrint(ResidualA),G4lrint(ResidualZ),U);
137   else limit=0.;
138
139   if (MaximalKineticEnergy <= limit)  return 0.0;
140
141
142   // if Coulomb barrier cutoff is superimposed for all cross sections the limit is the Coulomb Barrier
143   G4double LowerLimit= limit;
144
145   //  MaximalKineticEnergy: asimptotic value (already accounted for in G4EvaporationChannel)     
146
147   G4double UpperLimit = MaximalKineticEnergy;
148
149
150   G4double Width = IntegrateEmissionProbability(fragment,LowerLimit,UpperLimit);
151
152   return Width;
153 } else{
154   std::ostringstream errOs;
155   errOs << "Bad option for cross sections at evaporation"  <<G4endl;
156   throw G4HadronicException(__FILE__, __LINE__, errOs.str());
157 }
158 
159}
160
161/////////////////////////////////////////////////////////////////////
162
163G4double G4EvaporationProbability::
164IntegrateEmissionProbability(const G4Fragment & fragment, const G4double & Low, const G4double & Up )
165{
166
167  static const G4int N = 10;
168  // 10-Points Gauss-Legendre abcisas and weights
169  static const G4double w[N] = {
170    0.0666713443086881,
171    0.149451349150581,
172    0.219086362515982,
173    0.269266719309996,
174    0.295524224714753,
175    0.295524224714753,
176    0.269266719309996,
177    0.219086362515982,
178    0.149451349150581,
179    0.0666713443086881
180  };
181  static const G4double x[N] = {
182    -0.973906528517172,
183    -0.865063366688985,
184    -0.679409568299024,
185    -0.433395394129247,
186    -0.148874338981631,
187    0.148874338981631,
188    0.433395394129247,
189    0.679409568299024,
190    0.865063366688985,
191    0.973906528517172
192  };
193
194  G4double Total = 0.0;
195
196
197  for (G4int i = 0; i < N; i++) 
198    {
199
200      G4double KineticE = ((Up-Low)*x[i]+(Up+Low))/2.0;
201
202      Total += w[i]*ProbabilityDistributionFunction(fragment, KineticE);
203
204    }
205  Total *= (Up-Low)/2.0;
206  return Total;
207}
208
209
210/////////////////////////////////////////////////////////
211//New method (OPT=1,2,3,4)
212
213G4double G4EvaporationProbability::ProbabilityDistributionFunction( const G4Fragment & fragment, const G4double K)
214{ 
215
216 
217
218
219  G4double ResidualA = fragment.GetA() - theA;
220  G4double ResidualZ = fragment.GetZ() - theZ; 
221  G4double U = fragment.GetExcitationEnergy();
222
223  //        if(K <= theCoulombBarrierptr->GetCoulombBarrier(G4lrint(ResidualA),G4lrint(ResidualZ),U)) return 0.0;   
224
225  G4double delta1 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(ResidualA),static_cast<G4int>(ResidualZ));
226
227 
228  G4double delta0 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(fragment.GetA()),static_cast<G4int>(fragment.GetZ()));
229
230 
231  G4double ParticleMass = G4ParticleTable::GetParticleTable()->GetIonTable()->GetNucleusMass(theZ,theA);
232
233  G4double theSeparationEnergy= G4NucleiProperties::GetMassExcess(static_cast<G4int>(theA),static_cast<G4int>(theZ)) +
234    G4NucleiProperties::GetMassExcess(static_cast<G4int>(ResidualA),static_cast<G4int>(ResidualZ)) -
235    G4NucleiProperties::GetMassExcess(static_cast<G4int>(fragment.GetA()),static_cast<G4int>(fragment.GetZ()));
236
237  G4double a0 = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(fragment.GetA()),static_cast<G4int>(fragment.GetZ()),U - delta0);
238
239  G4double a1 = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(ResidualA),static_cast<G4int>(ResidualZ),U - theSeparationEnergy - delta1);
240 
241 
242  G4double E0=U-delta0;
243
244  G4double E1=U-theSeparationEnergy-delta1-K;
245
246  if (E1<0.) return 0.;
247
248  //JMQ 14/02/09 BUG fixed: hbarc should be in the denominator instead of hbar_Planck
249  //Without 1/hbar_Panck remains as a width
250  //  G4double  Prob=Gamma*ParticleMass/((pi*hbar_Planck)*(pi*hbar_Planck)*
251  //std::exp(2*std::sqrt(a0*E0)))*K*CrossSection(fragment,K)*std::exp(2*std::sqrt(a1*E1))*millibarn;
252
253  G4double Prob=Gamma*ParticleMass/((pi*hbarc)*(pi*hbarc)*std::exp(2*std::sqrt(a0*E0)))
254    *K*CrossSection(fragment,K)*std::exp(2*std::sqrt(a1*E1))*millibarn;
255
256  return Prob;
257}
258
259
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