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25 //
26 //
27 //
28 // by V. Lara
29 // --------------------------------------------------------------------
30
31 #include "G4StatMFMicroPartition.hh"
32 #include "G4PhysicalConstants.hh"
33 #include "G4SystemOfUnits.hh"
34 #include "G4HadronicException.hh"
35 #include "Randomize.hh"
36 #include "G4Log.hh"
37 #include "G4Exp.hh"
38 #include "G4Pow.hh"
39
40 // Copy constructor
41 G4StatMFMicroPartition::G4StatMFMicroPartition(const G4StatMFMicroPartition & )
42 {
43 throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::copy_constructor meant to not be accessible");
44 }
45
46 // Operators
47
48 G4StatMFMicroPartition & G4StatMFMicroPartition::
49 operator=(const G4StatMFMicroPartition & )
50 {
51 throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::operator= meant to not be accessible");
52 return *this;
53 }
54
55
56 G4bool G4StatMFMicroPartition::operator==(const G4StatMFMicroPartition & ) const
57 {
58 //throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::operator== meant to not be accessible");
59 return false;
60 }
61
62
63 G4bool G4StatMFMicroPartition::operator!=(const G4StatMFMicroPartition & ) const
64 {
65 //throw G4HadronicException(__FILE__, __LINE__, "G4StatMFMicroPartition::operator!= meant to not be accessible");
66 return true;
67 }
68
69 void G4StatMFMicroPartition::CoulombFreeEnergy(G4int anA)
70 {
71 // This Z independent factor in the Coulomb free energy
72 G4double CoulombConstFactor = G4StatMFParameters::GetCoulomb();
73
74 // We use the aproximation Z_f ~ Z/A * A_f
75
76 G4double ZA = G4double(theZ)/G4double(theA);
77
78 if (anA == 0 || anA == 1)
79 {
80 _theCoulombFreeEnergy.push_back(CoulombConstFactor*ZA*ZA);
81 }
82 else if (anA == 2 || anA == 3 || anA == 4)
83 {
84 // Z/A ~ 1/2
85 _theCoulombFreeEnergy.push_back(CoulombConstFactor*0.5
86 *anA*G4Pow::GetInstance()->Z23(anA));
87 }
88 else // anA > 4
89 {
90 _theCoulombFreeEnergy.push_back(CoulombConstFactor*ZA*ZA
91 *anA*G4Pow::GetInstance()->Z23(anA));
92 }
93 }
94
95 G4double G4StatMFMicroPartition::GetCoulombEnergy(void)
96 {
97 G4Pow* g4calc = G4Pow::GetInstance();
98 G4double CoulombFactor = 1.0/g4calc->A13(1.0+G4StatMFParameters::GetKappaCoulomb());
99
100 G4double CoulombEnergy = elm_coupling*0.6*theZ*theZ*CoulombFactor/
101 (G4StatMFParameters::Getr0()*g4calc->Z13(theA));
102
103 G4double ZA = G4double(theZ)/G4double(theA);
104 for (unsigned int i = 0; i < _thePartition.size(); i++)
105 CoulombEnergy += _theCoulombFreeEnergy[i] - elm_coupling*0.6*
106 ZA*ZA*_thePartition[i]*g4calc->Z23(_thePartition[i])/
107 G4StatMFParameters::Getr0();
108
109 return CoulombEnergy;
110 }
111
112 G4double G4StatMFMicroPartition::GetPartitionEnergy(G4double T)
113 {
114 G4Pow* g4calc = G4Pow::GetInstance();
115 G4double CoulombFactor = 1.0/g4calc->A13(1.0+G4StatMFParameters::GetKappaCoulomb());
116
117 G4double PartitionEnergy = 0.0;
118
119 // We use the aprox that Z_f ~ Z/A * A_f
120 for (unsigned int i = 0; i < _thePartition.size(); i++)
121 {
122 if (_thePartition[i] == 0 || _thePartition[i] == 1)
123 {
124 PartitionEnergy += _theCoulombFreeEnergy[i];
125 }
126 else if (_thePartition[i] == 2)
127 {
128 PartitionEnergy +=
129 -2.796 // Binding Energy of deuteron ??????
130 + _theCoulombFreeEnergy[i];
131 }
132 else if (_thePartition[i] == 3)
133 {
134 PartitionEnergy +=
135 -9.224 // Binding Energy of trtion/He3 ??????
136 + _theCoulombFreeEnergy[i];
137 }
138 else if (_thePartition[i] == 4)
139 {
140 PartitionEnergy +=
141 -30.11 // Binding Energy of ALPHA ??????
142 + _theCoulombFreeEnergy[i]
143 + 4.*T*T/InvLevelDensity(4.);
144 }
145 else
146 {
147 PartitionEnergy +=
148 //Volume term
149 (- G4StatMFParameters::GetE0() +
150 T*T/InvLevelDensity(_thePartition[i]))
151 *_thePartition[i] +
152
153 // Symmetry term
154 G4StatMFParameters::GetGamma0()*
155 (1.0-2.0*theZ/theA)*(1.0-2.0*theZ/theA)*_thePartition[i] +
156
157 // Surface term
158 (G4StatMFParameters::Beta(T) - T*G4StatMFParameters::DBetaDT(T))*
159 g4calc->Z23(_thePartition[i]) +
160
161 // Coulomb term
162 _theCoulombFreeEnergy[i];
163 }
164 }
165
166 PartitionEnergy += elm_coupling*0.6*theZ*theZ*CoulombFactor/
167 (G4StatMFParameters::Getr0()*g4calc->Z13(theA))
168 + 1.5*T*(_thePartition.size()-1);
169
170 return PartitionEnergy;
171 }
172
173 G4double G4StatMFMicroPartition::CalcPartitionTemperature(G4double U,
174 G4double FreeInternalE0)
175 {
176 G4double PartitionEnergy = GetPartitionEnergy(0.0);
177
178 // If this happens, T = 0 MeV, which means that probability for this
179 // partition will be 0
180 if (std::fabs(U + FreeInternalE0 - PartitionEnergy) < 0.003) return -1.0;
181
182 // Calculate temperature by midpoint method
183
184 // Bracketing the solution
185 G4double Ta = 0.001;
186 G4double Tb = std::max(std::sqrt(8.0*U/theA),0.0012*MeV);
187 G4double Tmid = 0.0;
188
189 G4double Da = (U + FreeInternalE0 - GetPartitionEnergy(Ta))/U;
190 G4double Db = (U + FreeInternalE0 - GetPartitionEnergy(Tb))/U;
191
192 G4int maxit = 0;
193 // Loop checking, 05-Aug-2015, Vladimir Ivanchenko
194 while (Da*Db > 0.0 && maxit < 1000)
195 {
196 ++maxit;
197 Tb += 0.5*Tb;
198 Db = (U + FreeInternalE0 - GetPartitionEnergy(Tb))/U;
199 }
200
201 G4double eps = 1.0e-14*std::abs(Ta-Tb);
202
203 for (G4int i = 0; i < 1000; i++)
204 {
205 Tmid = (Ta+Tb)/2.0;
206 if (std::fabs(Ta-Tb) <= eps) return Tmid;
207 G4double Dmid = (U + FreeInternalE0 - GetPartitionEnergy(Tmid))/U;
208 if (std::fabs(Dmid) < 0.003) return Tmid;
209 if (Da*Dmid < 0.0)
210 {
211 Tb = Tmid;
212 Db = Dmid;
213 }
214 else
215 {
216 Ta = Tmid;
217 Da = Dmid;
218 }
219 }
220 // if we arrive here the temperature could not be calculated
221 G4cout << "G4StatMFMicroPartition::CalcPartitionTemperature: I can't calculate the temperature"
222 << G4endl;
223 // and set probability to 0 returning T < 0
224 return -1.0;
225
226 }
227
228 G4double G4StatMFMicroPartition::CalcPartitionProbability(G4double U,
229 G4double FreeInternalE0,
230 G4double SCompound)
231 {
232 G4double T = CalcPartitionTemperature(U,FreeInternalE0);
233 if ( T <= 0.0) return _Probability = 0.0;
234 _Temperature = T;
235
236 G4Pow* g4calc = G4Pow::GetInstance();
237
238 // Factorial of fragment multiplicity
239 G4double Fact = 1.0;
240 unsigned int i;
241 for (i = 0; i < _thePartition.size() - 1; i++)
242 {
243 G4double f = 1.0;
244 for (unsigned int ii = i+1; i< _thePartition.size(); i++)
245 {
246 if (_thePartition[i] == _thePartition[ii]) f++;
247 }
248 Fact *= f;
249 }
250
251 G4double ProbDegeneracy = 1.0;
252 G4double ProbA32 = 1.0;
253
254 for (i = 0; i < _thePartition.size(); i++)
255 {
256 ProbDegeneracy *= GetDegeneracyFactor(_thePartition[i]);
257 ProbA32 *= _thePartition[i]*std::sqrt((G4double)_thePartition[i]);
258 }
259
260 // Compute entropy
261 G4double PartitionEntropy = 0.0;
262 for (i = 0; i < _thePartition.size(); i++)
263 {
264 // interaction entropy for alpha
265 if (_thePartition[i] == 4)
266 {
267 PartitionEntropy +=
268 2.0*T*_thePartition[i]/InvLevelDensity(_thePartition[i]);
269 }
270 // interaction entropy for Af > 4
271 else if (_thePartition[i] > 4)
272 {
273 PartitionEntropy +=
274 2.0*T*_thePartition[i]/InvLevelDensity(_thePartition[i])
275 - G4StatMFParameters::DBetaDT(T) * g4calc->Z23(_thePartition[i]);
276 }
277 }
278
279 // Thermal Wave Lenght = std::sqrt(2 pi hbar^2 / nucleon_mass T)
280 G4double ThermalWaveLenght3 = 16.15*fermi/std::sqrt(T);
281 ThermalWaveLenght3 = ThermalWaveLenght3*ThermalWaveLenght3*ThermalWaveLenght3;
282
283 // Translational Entropy
284 G4double kappa = 1. + elm_coupling*(g4calc->Z13((G4int)_thePartition.size())-1.0)
285 /(G4StatMFParameters::Getr0()*g4calc->Z13(theA));
286 kappa = kappa*kappa*kappa;
287 kappa -= 1.;
288 G4double V0 = (4./3.)*pi*theA*G4StatMFParameters::Getr0()*G4StatMFParameters::Getr0()*
289 G4StatMFParameters::Getr0();
290 G4double FreeVolume = kappa*V0;
291 G4double TranslationalS = std::max(0.0, G4Log(ProbA32/Fact) +
292 (_thePartition.size()-1.0)*G4Log(FreeVolume/ThermalWaveLenght3) +
293 1.5*(_thePartition.size()-1.0) - 1.5*g4calc->logZ(theA));
294
295 PartitionEntropy += G4Log(ProbDegeneracy) + TranslationalS;
296 _Entropy = PartitionEntropy;
297
298 // And finally compute probability of fragment configuration
299 G4double exponent = PartitionEntropy-SCompound;
300 if (exponent > 300.0) exponent = 300.0;
301 return _Probability = G4Exp(exponent);
302 }
303
304 G4double G4StatMFMicroPartition::GetDegeneracyFactor(G4int A)
305 {
306 // Degeneracy factors are statistical factors
307 // DegeneracyFactor for nucleon is (2S_n + 1)(2I_n + 1) = 4
308 G4double DegFactor = 0;
309 if (A > 4) DegFactor = 1.0;
310 else if (A == 1) DegFactor = 4.0; // nucleon
311 else if (A == 2) DegFactor = 3.0; // Deuteron
312 else if (A == 3) DegFactor = 4.0; // Triton + He3
313 else if (A == 4) DegFactor = 1.0; // alpha
314 return DegFactor;
315 }
316
317 G4StatMFChannel * G4StatMFMicroPartition::ChooseZ(G4int A0, G4int Z0, G4double MeanT)
318 // Gives fragments charges
319 {
320 std::vector<G4int> FragmentsZ;
321
322 G4int ZBalance = 0;
323 do
324 {
325 G4double CC = G4StatMFParameters::GetGamma0()*8.0;
326 G4int SumZ = 0;
327 for (unsigned int i = 0; i < _thePartition.size(); i++)
328 {
329 G4double ZMean;
330 G4double Af = _thePartition[i];
331 if (Af > 1.5 && Af < 4.5) ZMean = 0.5*Af;
332 else ZMean = Af*Z0/A0;
333 G4double ZDispersion = std::sqrt(Af * MeanT/CC);
334 G4int Zf;
335 do
336 {
337 Zf = static_cast<G4int>(G4RandGauss::shoot(ZMean,ZDispersion));
338 }
339 // Loop checking, 05-Aug-2015, Vladimir Ivanchenko
340 while (Zf < 0 || Zf > Af);
341 FragmentsZ.push_back(Zf);
342 SumZ += Zf;
343 }
344 ZBalance = Z0 - SumZ;
345 }
346 // Loop checking, 05-Aug-2015, Vladimir Ivanchenko
347 while (std::abs(ZBalance) > 1);
348 FragmentsZ[0] += ZBalance;
349
350 G4StatMFChannel * theChannel = new G4StatMFChannel;
351 for (unsigned int i = 0; i < _thePartition.size(); i++)
352 {
353 theChannel->CreateFragment(_thePartition[i],FragmentsZ[i]);
354 }
355
356 return theChannel;
357 }
358