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25 // 25 //
26 // Author: Sebastien Incerti 26 // Author: Sebastien Incerti
27 // 22 January 2012 27 // 22 January 2012
28 // on base of G4LivermoreGammaConversi << 28 // on base of G4LivermoreGammaConversionModel
29 // and G4LivermoreRayleighModel (MT ve <<
30 // <<
31 // Modifications: Zhuxin Li@CENBG <<
32 // 11 March 2020 <<
33 // derives from G4PairProductio <<
34 // ------------------------------------------- <<
35 29
36 #include "G4LivermoreGammaConversionModel.hh" 30 #include "G4LivermoreGammaConversionModel.hh"
37 <<
38 #include "G4AutoLock.hh" <<
39 #include "G4Electron.hh" <<
40 #include "G4EmParameters.hh" <<
41 #include "G4Exp.hh" <<
42 #include "G4ParticleChangeForGamma.hh" <<
43 #include "G4PhysicalConstants.hh" 31 #include "G4PhysicalConstants.hh"
44 #include "G4PhysicsFreeVector.hh" <<
45 #include "G4SystemOfUnits.hh" 32 #include "G4SystemOfUnits.hh"
46 33
47 namespace <<
48 { <<
49 G4Mutex LivermoreGammaConversionModelMutex = G <<
50 } <<
51 <<
52 //....oooOO0OOooo........oooOO0OOooo........oo <<
53 //....oooOO0OOooo........oooOO0OOooo........oo 34 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
54 35
55 G4PhysicsFreeVector* G4LivermoreGammaConversio << 36 using namespace std;
56 G4String G4LivermoreGammaConversionModel::gDat << 37
>> 38 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
57 39
58 G4LivermoreGammaConversionModel::G4LivermoreGa << 40 G4LivermoreGammaConversionModel::G4LivermoreGammaConversionModel(const G4ParticleDefinition*,
59 << 41 const G4String& nam)
60 : G4PairProductionRelModel(p, nam) << 42 :G4VEmModel(nam),smallEnergy(2.*MeV),isInitialised(false),maxZ(99)
61 { 43 {
62 fParticleChange = nullptr; << 44 fParticleChange = 0;
63 lowEnergyLimit = 2. * CLHEP::electron_mass_c << 45
64 verboseLevel = 0; << 46 lowEnergyLimit = 2.0*electron_mass_c2;
>> 47 data.resize(maxZ+1,0);
>> 48
>> 49 verboseLevel= 0;
65 // Verbosity scale for debugging purposes: 50 // Verbosity scale for debugging purposes:
66 // 0 = nothing << 51 // 0 = nothing
67 // 1 = calculation of cross sections, file o 52 // 1 = calculation of cross sections, file openings...
68 // 2 = entering in methods 53 // 2 = entering in methods
69 if (verboseLevel > 0) { << 54
>> 55 if(verboseLevel > 0)
>> 56 {
70 G4cout << "G4LivermoreGammaConversionModel 57 G4cout << "G4LivermoreGammaConversionModel is constructed " << G4endl;
71 } 58 }
72 } 59 }
73 60
74 //....oooOO0OOooo........oooOO0OOooo........oo 61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
75 62
76 G4LivermoreGammaConversionModel::~G4LivermoreG 63 G4LivermoreGammaConversionModel::~G4LivermoreGammaConversionModel()
77 { << 64 {
78 if (IsMaster()) { << 65 for(G4int i=0; i<=maxZ; ++i) { delete data[i]; }
79 for (G4int i = 0; i <= maxZ; ++i) { <<
80 if (data[i]) { <<
81 delete data[i]; <<
82 data[i] = nullptr; <<
83 } <<
84 } <<
85 } <<
86 } 66 }
87 67
88 //....oooOO0OOooo........oooOO0OOooo........oo 68 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
89 69
90 void G4LivermoreGammaConversionModel::Initiali << 70 void
91 << 71 G4LivermoreGammaConversionModel::Initialise(const G4ParticleDefinition* particle,
>> 72 const G4DataVector& cuts)
92 { 73 {
93 G4PairProductionRelModel::Initialise(particl << 74 if (verboseLevel > 1)
94 if (verboseLevel > 1) { << 75 {
95 G4cout << "Calling Initialise() of G4Liver 76 G4cout << "Calling Initialise() of G4LivermoreGammaConversionModel." << G4endl
96 << "Energy range: " << LowEnergyLim << 77 << "Energy range: "
97 << " GeV isMater: " << IsMaster() < << 78 << LowEnergyLimit() / MeV << " MeV - "
98 } << 79 << HighEnergyLimit() / GeV << " GeV"
99 << 80 << G4endl;
100 if (IsMaster()) { << 81 }
101 // Initialise element selector << 82
102 InitialiseElementSelectors(particle, cuts) << 83 // Initialise element selector
103 << 84
104 // Access to elements << 85 InitialiseElementSelectors(particle, cuts);
105 const G4ElementTable* elemTable = G4Elemen << 86
106 std::size_t numElems = (*elemTable).size() << 87 // Access to elements
107 for (std::size_t ie = 0; ie < numElems; ++ << 88
108 const G4Element* elem = (*elemTable)[ie] << 89 char* path = getenv("G4LEDATA");
109 const G4int Z = std::min(maxZ, elem->Get << 90
110 if (data[Z] == nullptr) { << 91 G4ProductionCutsTable* theCoupleTable =
111 ReadData(Z); << 92 G4ProductionCutsTable::GetProductionCutsTable();
112 } << 93 G4int numOfCouples = theCoupleTable->GetTableSize();
>> 94
>> 95 for(G4int i=0; i<numOfCouples; ++i)
>> 96 {
>> 97 const G4Material* material =
>> 98 theCoupleTable->GetMaterialCutsCouple(i)->GetMaterial();
>> 99 const G4ElementVector* theElementVector = material->GetElementVector();
>> 100 G4int nelm = material->GetNumberOfElements();
>> 101
>> 102 for (G4int j=0; j<nelm; ++j)
>> 103 {
>> 104
>> 105 G4int Z = (G4int)(*theElementVector)[j]->GetZ();
>> 106 if(Z < 1) { Z = 1; }
>> 107 else if(Z > maxZ) { Z = maxZ; }
>> 108 if(!data[Z]) { ReadData(Z, path); }
113 } 109 }
114 } 110 }
115 if (isInitialised) { << 111 //
116 return; << 112
117 } << 113 if(isInitialised) { return; }
118 fParticleChange = GetParticleChangeForGamma( 114 fParticleChange = GetParticleChangeForGamma();
119 isInitialised = true; 115 isInitialised = true;
120 } 116 }
121 117
122 //....oooOO0OOooo........oooOO0OOooo........oo 118 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
123 119
124 const G4String& G4LivermoreGammaConversionMode << 120 void G4LivermoreGammaConversionModel::ReadData(size_t Z, const char* path)
125 { 121 {
126 // no check in this method - environment var << 122 if (verboseLevel > 1)
127 if (gDataDirectory.empty()) { << 123 {
128 auto param = G4EmParameters::Instance(); << 124 G4cout << "Calling ReadData() of G4LivermoreGammaConversionModel"
129 std::ostringstream ost; << 125 << G4endl;
130 if (param->LivermoreDataDir() == "livermor << 126 }
131 ost << param->GetDirLEDATA() << "/liverm << 127
132 useSpline = true; << 128 if(data[Z]) { return; }
>> 129
>> 130 const char* datadir = path;
>> 131
>> 132 if(!datadir)
>> 133 {
>> 134 datadir = getenv("G4LEDATA");
>> 135 if(!datadir)
>> 136 {
>> 137 G4Exception("G4LivermoreGammaConversionModel::ReadData()",
>> 138 "em0006",FatalException,
>> 139 "Environment variable G4LEDATA not defined");
>> 140 return;
133 } 141 }
134 else { <<
135 ost << param->GetDirLEDATA() << "/epics2 <<
136 } <<
137 gDataDirectory = ost.str(); <<
138 } <<
139 return gDataDirectory; <<
140 } <<
141 <<
142 //....oooOO0OOooo........oooOO0OOooo........oo <<
143 <<
144 void G4LivermoreGammaConversionModel::ReadData <<
145 { <<
146 if (verboseLevel > 1) { <<
147 G4cout << "Calling ReadData() of G4Livermo <<
148 } <<
149 <<
150 if (data[Z] != nullptr) { <<
151 return; <<
152 } 142 }
153 143
>> 144 //
>> 145
>> 146 data[Z] = new G4LPhysicsFreeVector();
>> 147
>> 148 // Activation of spline interpolation
>> 149 data[Z] ->SetSpline(true);
>> 150 //
>> 151
154 std::ostringstream ost; 152 std::ostringstream ost;
155 ost << FindDirectoryPath() << "pp-cs-" << Z << 153 ost << datadir << "/livermore/pair/pp-cs-" << Z <<".dat";
156 <<
157 data[Z] = new G4PhysicsFreeVector(useSpline) <<
158 <<
159 std::ifstream fin(ost.str().c_str()); 154 std::ifstream fin(ost.str().c_str());
160 << 155
161 if (!fin.is_open()) { << 156 if( !fin.is_open())
>> 157 {
162 G4ExceptionDescription ed; 158 G4ExceptionDescription ed;
163 ed << "G4LivermoreGammaConversionModel dat << 159 ed << "G4LivermoreGammaConversionModel data file <" << ost.str().c_str()
164 << G4endl; << 160 << "> is not opened!" << G4endl;
165 G4Exception("G4LivermoreGammaConversionMod << 161 G4Exception("G4LivermoreGammaConversionModel::ReadData()",
166 "G4LEDATA version should be G4 << 162 "em0003",FatalException,
>> 163 ed,"G4LEDATA version should be G4EMLOW6.27 or later.");
167 return; 164 return;
168 } << 165 }
169 else { << 166
170 if (verboseLevel > 1) { << 167 else
171 G4cout << "File " << ost.str() << " is o << 168 {
172 } << 169
173 << 170 if(verboseLevel > 3) { G4cout << "File " << ost.str()
>> 171 << " is opened by G4LivermoreGammaConversionModel" << G4endl;}
>> 172
174 data[Z]->Retrieve(fin, true); 173 data[Z]->Retrieve(fin, true);
175 } << 174 }
176 // Activation of spline interpolation << 175
177 if (useSpline) data[Z]->FillSecondDerivative << 176
178 } 177 }
179 178
180 //....oooOO0OOooo........oooOO0OOooo........oo 179 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
181 180
182 G4double << 181 G4double
183 G4LivermoreGammaConversionModel::ComputeCrossS << 182 G4LivermoreGammaConversionModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
184 << 183 G4double GammaEnergy,
185 << 184 G4double Z, G4double,
>> 185 G4double, G4double)
186 { 186 {
187 if (verboseLevel > 1) { << 187 if (verboseLevel > 1)
188 G4cout << "G4LivermoreGammaConversionModel << 188 {
>> 189 G4cout << "Calling ComputeCrossSectionPerAtom() of G4LivermoreGammaConversionModel"
>> 190 << G4endl;
189 } 191 }
190 192
191 if (GammaEnergy < lowEnergyLimit) { << 193 if (GammaEnergy < lowEnergyLimit) { return 0.0; }
192 return 0.0; <<
193 } <<
194 194
195 G4double xs = 0.0; 195 G4double xs = 0.0;
>> 196
>> 197 G4int intZ=G4int(Z);
196 198
197 G4int intZ = std::max(1, std::min(G4lrint(Z) << 199 if(intZ < 1 || intZ > maxZ) { return xs; }
198 200
199 G4PhysicsFreeVector* pv = data[intZ]; << 201 G4LPhysicsFreeVector* pv = data[intZ];
200 202
201 // if element was not initialised << 203 // element was not initialised
202 // do initialisation safely for MT mode << 204 if(!pv)
203 if (pv == nullptr) { << 205 {
204 InitialiseForElement(particle, intZ); << 206 char* path = getenv("G4LEDATA");
>> 207 ReadData(intZ, path);
205 pv = data[intZ]; 208 pv = data[intZ];
206 if (pv == nullptr) { << 209 if(!pv) { return xs; }
207 return xs; <<
208 } <<
209 } 210 }
210 // x-section is taken from the table 211 // x-section is taken from the table
211 xs = pv->Value(GammaEnergy); << 212 xs = pv->Value(GammaEnergy);
212 213
213 if (verboseLevel > 0) { << 214 if(verboseLevel > 0)
214 G4cout << "*** Gamma conversion xs for Z=" << 215 {
215 << " cs=" << xs / millibarn << " m << 216 G4int n = pv->GetVectorLength() - 1;
>> 217 G4cout << "****** DEBUG: tcs value for Z=" << Z << " at energy (MeV)=" << GammaEnergy/MeV << G4endl;
>> 218 G4cout << " cs (Geant4 internal unit)=" << xs << G4endl;
>> 219 G4cout << " -> first cs value in EADL data file (iu) =" << (*pv)[0] << G4endl;
>> 220 G4cout << " -> last cs value in EADL data file (iu) =" << (*pv)[n] << G4endl;
>> 221 G4cout << "*********************************************************" << G4endl;
216 } 222 }
>> 223
217 return xs; 224 return xs;
>> 225
218 } 226 }
219 227
220 //....oooOO0OOooo........oooOO0OOooo........oo << 228 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
221 229
222 void G4LivermoreGammaConversionModel::Initiali << 230 void G4LivermoreGammaConversionModel::SampleSecondaries(
>> 231 std::vector<G4DynamicParticle*>* fvect,
>> 232 const G4MaterialCutsCouple* couple,
>> 233 const G4DynamicParticle* aDynamicGamma,
>> 234 G4double, G4double)
223 { 235 {
224 G4AutoLock l(&LivermoreGammaConversionModelM << 236
225 if (data[Z] == nullptr) { << 237 // The energies of the e+ e- secondaries are sampled using the Bethe - Heitler
226 ReadData(Z); << 238 // cross sections with Coulomb correction. A modified version of the random
227 } << 239 // number techniques of Butcher & Messel is used (Nuc Phys 20(1960),15).
228 l.unlock(); << 240
>> 241 // Note 1 : Effects due to the breakdown of the Born approximation at low
>> 242 // energy are ignored.
>> 243 // Note 2 : The differential cross section implicitly takes account of
>> 244 // pair creation in both nuclear and atomic electron fields. However triplet
>> 245 // prodution is not generated.
>> 246
>> 247 if (verboseLevel > 1)
>> 248 G4cout << "Calling SampleSecondaries() of G4LivermoreGammaConversionModel" << G4endl;
>> 249
>> 250 G4double photonEnergy = aDynamicGamma->GetKineticEnergy();
>> 251 G4ParticleMomentum photonDirection = aDynamicGamma->GetMomentumDirection();
>> 252
>> 253 G4double epsilon ;
>> 254 G4double epsilon0Local = electron_mass_c2 / photonEnergy ;
>> 255
>> 256 // Do it fast if photon energy < 2. MeV
>> 257 if (photonEnergy < smallEnergy )
>> 258 {
>> 259 epsilon = epsilon0Local + (0.5 - epsilon0Local) * G4UniformRand();
>> 260 }
>> 261 else
>> 262 {
>> 263 // Select randomly one element in the current material
>> 264
>> 265 const G4ParticleDefinition* particle = aDynamicGamma->GetDefinition();
>> 266 const G4Element* element = SelectRandomAtom(couple,particle,photonEnergy);
>> 267
>> 268 if (element == 0)
>> 269 {
>> 270 G4cout << "G4LivermoreGammaConversionModel::SampleSecondaries - element = 0"
>> 271 << G4endl;
>> 272 return;
>> 273 }
>> 274 G4IonisParamElm* ionisation = element->GetIonisation();
>> 275 if (ionisation == 0)
>> 276 {
>> 277 G4cout << "G4LivermoreGammaConversionModel::SampleSecondaries - ionisation = 0"
>> 278 << G4endl;
>> 279 return;
>> 280 }
>> 281
>> 282 // Extract Coulomb factor for this Element
>> 283 G4double fZ = 8. * (ionisation->GetlogZ3());
>> 284 if (photonEnergy > 50. * MeV) fZ += 8. * (element->GetfCoulomb());
>> 285
>> 286 // Limits of the screening variable
>> 287 G4double screenFactor = 136. * epsilon0Local / (element->GetIonisation()->GetZ3()) ;
>> 288 G4double screenMax = std::exp ((42.24 - fZ)/8.368) - 0.952 ;
>> 289 G4double screenMin = std::min(4.*screenFactor,screenMax) ;
>> 290
>> 291 // Limits of the energy sampling
>> 292 G4double epsilon1 = 0.5 - 0.5 * std::sqrt(1. - screenMin / screenMax) ;
>> 293 G4double epsilonMin = std::max(epsilon0Local,epsilon1);
>> 294 G4double epsilonRange = 0.5 - epsilonMin ;
>> 295
>> 296 // Sample the energy rate of the created electron (or positron)
>> 297 G4double screen;
>> 298 G4double gReject ;
>> 299
>> 300 G4double f10 = ScreenFunction1(screenMin) - fZ;
>> 301 G4double f20 = ScreenFunction2(screenMin) - fZ;
>> 302 G4double normF1 = std::max(f10 * epsilonRange * epsilonRange,0.);
>> 303 G4double normF2 = std::max(1.5 * f20,0.);
>> 304
>> 305 do
>> 306 {
>> 307 if (normF1 / (normF1 + normF2) > G4UniformRand() )
>> 308 {
>> 309 epsilon = 0.5 - epsilonRange * std::pow(G4UniformRand(), 0.333333) ;
>> 310 screen = screenFactor / (epsilon * (1. - epsilon));
>> 311 gReject = (ScreenFunction1(screen) - fZ) / f10 ;
>> 312 }
>> 313 else
>> 314 {
>> 315 epsilon = epsilonMin + epsilonRange * G4UniformRand();
>> 316 screen = screenFactor / (epsilon * (1 - epsilon));
>> 317 gReject = (ScreenFunction2(screen) - fZ) / f20 ;
>> 318 }
>> 319 } while ( gReject < G4UniformRand() );
>> 320
>> 321 } // End of epsilon sampling
>> 322
>> 323 // Fix charges randomly
>> 324
>> 325 G4double electronTotEnergy;
>> 326 G4double positronTotEnergy;
>> 327
>> 328 if (G4UniformRand() > 0.5)
>> 329 {
>> 330 electronTotEnergy = (1. - epsilon) * photonEnergy;
>> 331 positronTotEnergy = epsilon * photonEnergy;
>> 332 }
>> 333 else
>> 334 {
>> 335 positronTotEnergy = (1. - epsilon) * photonEnergy;
>> 336 electronTotEnergy = epsilon * photonEnergy;
>> 337 }
>> 338
>> 339 // Scattered electron (positron) angles. ( Z - axis along the parent photon)
>> 340 // Universal distribution suggested by L. Urban (Geant3 manual (1993) Phys211),
>> 341 // derived from Tsai distribution (Rev. Mod. Phys. 49, 421 (1977)
>> 342
>> 343 G4double u;
>> 344 const G4double a1 = 0.625;
>> 345 G4double a2 = 3. * a1;
>> 346 // G4double d = 27. ;
>> 347
>> 348 // if (9. / (9. + d) > G4UniformRand())
>> 349 if (0.25 > G4UniformRand())
>> 350 {
>> 351 u = - std::log(G4UniformRand() * G4UniformRand()) / a1 ;
>> 352 }
>> 353 else
>> 354 {
>> 355 u = - std::log(G4UniformRand() * G4UniformRand()) / a2 ;
>> 356 }
>> 357
>> 358 G4double thetaEle = u*electron_mass_c2/electronTotEnergy;
>> 359 G4double thetaPos = u*electron_mass_c2/positronTotEnergy;
>> 360 G4double phi = twopi * G4UniformRand();
>> 361
>> 362 G4double dxEle= std::sin(thetaEle)*std::cos(phi),dyEle= std::sin(thetaEle)*std::sin(phi),dzEle=std::cos(thetaEle);
>> 363 G4double dxPos=-std::sin(thetaPos)*std::cos(phi),dyPos=-std::sin(thetaPos)*std::sin(phi),dzPos=std::cos(thetaPos);
>> 364
>> 365
>> 366 // Kinematics of the created pair:
>> 367 // the electron and positron are assumed to have a symetric angular
>> 368 // distribution with respect to the Z axis along the parent photon
>> 369
>> 370 G4double electronKineEnergy = std::max(0.,electronTotEnergy - electron_mass_c2) ;
>> 371
>> 372 G4ThreeVector electronDirection (dxEle, dyEle, dzEle);
>> 373 electronDirection.rotateUz(photonDirection);
>> 374
>> 375 G4DynamicParticle* particle1 = new G4DynamicParticle (G4Electron::Electron(),
>> 376 electronDirection,
>> 377 electronKineEnergy);
>> 378
>> 379 // The e+ is always created
>> 380 G4double positronKineEnergy = std::max(0.,positronTotEnergy - electron_mass_c2) ;
>> 381
>> 382 G4ThreeVector positronDirection (dxPos, dyPos, dzPos);
>> 383 positronDirection.rotateUz(photonDirection);
>> 384
>> 385 // Create G4DynamicParticle object for the particle2
>> 386 G4DynamicParticle* particle2 = new G4DynamicParticle(G4Positron::Positron(),
>> 387 positronDirection,
>> 388 positronKineEnergy);
>> 389 // Fill output vector
>> 390 fvect->push_back(particle1);
>> 391 fvect->push_back(particle2);
>> 392
>> 393 // kill incident photon
>> 394 fParticleChange->SetProposedKineticEnergy(0.);
>> 395 fParticleChange->ProposeTrackStatus(fStopAndKill);
>> 396
229 } 397 }
230 398
231 //....oooOO0OOooo........oooOO0OOooo........oo << 399 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 400
>> 401 G4double
>> 402 G4LivermoreGammaConversionModel::ScreenFunction1(G4double screenVariable)
>> 403 {
>> 404 // Compute the value of the screening function 3*phi1 - phi2
>> 405
>> 406 G4double value;
>> 407
>> 408 if (screenVariable > 1.)
>> 409 value = 42.24 - 8.368 * std::log(screenVariable + 0.952);
>> 410 else
>> 411 value = 42.392 - screenVariable * (7.796 - 1.961 * screenVariable);
>> 412
>> 413 return value;
>> 414 }
>> 415
>> 416 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 417
>> 418 G4double
>> 419 G4LivermoreGammaConversionModel::ScreenFunction2(G4double screenVariable)
>> 420 {
>> 421 // Compute the value of the screening function 1.5*phi1 - 0.5*phi2
>> 422
>> 423 G4double value;
>> 424
>> 425 if (screenVariable > 1.)
>> 426 value = 42.24 - 8.368 * std::log(screenVariable + 0.952);
>> 427 else
>> 428 value = 41.405 - screenVariable * (5.828 - 0.8945 * screenVariable);
>> 429
>> 430 return value;
>> 431 }
>> 432
232 433