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25 // 25 //
>> 26 // $Id: G4PenelopeAnnihilationModel.cc,v 1.2 2008/12/04 14:09:36 pandola Exp $
>> 27 // GEANT4 tag $Name: geant4-09-02-patch-03 $
26 // 28 //
27 // Author: Luciano Pandola 29 // Author: Luciano Pandola
28 // 30 //
29 // History: 31 // History:
30 // -------- 32 // --------
31 // 29 Oct 2008 L Pandola Migration from p 33 // 29 Oct 2008 L Pandola Migration from process to model
32 // 15 Apr 2009 V Ivanchenko Cleanup initiali << 34 //
33 // secondaries: <<
34 // - apply internal high-ener <<
35 // - do not apply low-energy <<
36 // - do not use G4ElementSele <<
37 // 02 Oct 2013 L.Pandola Migration to MT <<
38 35
39 #include "G4PenelopeAnnihilationModel.hh" 36 #include "G4PenelopeAnnihilationModel.hh"
40 #include "G4PhysicalConstants.hh" <<
41 #include "G4SystemOfUnits.hh" <<
42 #include "G4ParticleDefinition.hh" 37 #include "G4ParticleDefinition.hh"
43 #include "G4MaterialCutsCouple.hh" 38 #include "G4MaterialCutsCouple.hh"
44 #include "G4ProductionCutsTable.hh" 39 #include "G4ProductionCutsTable.hh"
45 #include "G4DynamicParticle.hh" 40 #include "G4DynamicParticle.hh"
46 #include "G4Gamma.hh" 41 #include "G4Gamma.hh"
47 42
48 //....oooOO0OOooo........oooOO0OOooo........oo 43 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
49 44
50 G4double G4PenelopeAnnihilationModel::fPielr2 <<
51 45
52 G4PenelopeAnnihilationModel::G4PenelopeAnnihil << 46 G4PenelopeAnnihilationModel::G4PenelopeAnnihilationModel(const G4ParticleDefinition*,
53 c 47 const G4String& nam)
54 :G4VEmModel(nam),fParticleChange(nullptr),fP << 48 :G4VEmModel(nam),isInitialised(false)
55 { 49 {
56 fIntrinsicLowEnergyLimit = 0.0; << 50 fIntrinsicLowEnergyLimit = 0.0*eV;
57 fIntrinsicHighEnergyLimit = 100.0*GeV; 51 fIntrinsicHighEnergyLimit = 100.0*GeV;
>> 52 SetLowEnergyLimit(fIntrinsicLowEnergyLimit);
58 SetHighEnergyLimit(fIntrinsicHighEnergyLimit 53 SetHighEnergyLimit(fIntrinsicHighEnergyLimit);
59 << 54
60 if (part) <<
61 SetParticle(part); <<
62 <<
63 //Calculate variable that will be used later 55 //Calculate variable that will be used later on
64 fPielr2 = pi*classic_electr_radius*classic_e 56 fPielr2 = pi*classic_electr_radius*classic_electr_radius;
65 57
66 fVerboseLevel= 0; << 58 verboseLevel= 0;
67 // Verbosity scale: 59 // Verbosity scale:
68 // 0 = nothing 60 // 0 = nothing
69 // 1 = warning for energy non-conservation 61 // 1 = warning for energy non-conservation
70 // 2 = details of energy budget 62 // 2 = details of energy budget
71 // 3 = calculation of cross sections, file o 63 // 3 = calculation of cross sections, file openings, sampling of atoms
72 // 4 = entering in methods 64 // 4 = entering in methods
>> 65
73 } 66 }
74 67
75 //....oooOO0OOooo........oooOO0OOooo........oo 68 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
76 69
77 G4PenelopeAnnihilationModel::~G4PenelopeAnnihi 70 G4PenelopeAnnihilationModel::~G4PenelopeAnnihilationModel()
78 {;} 71 {;}
79 72
80 //....oooOO0OOooo........oooOO0OOooo........oo 73 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
81 74
82 void G4PenelopeAnnihilationModel::Initialise(c << 75 void G4PenelopeAnnihilationModel::Initialise(const G4ParticleDefinition* particle,
83 const G4DataVector&) << 76 const G4DataVector& cuts)
84 { 77 {
85 if (fVerboseLevel > 3) << 78 if (verboseLevel > 3)
86 G4cout << "Calling G4PenelopeAnnihilationM 79 G4cout << "Calling G4PenelopeAnnihilationModel::Initialise()" << G4endl;
87 SetParticle(part); <<
88 80
89 if (IsMaster() && part == fParticle) << 81 InitialiseElementSelectors(particle,cuts);
>> 82 if (LowEnergyLimit() < fIntrinsicLowEnergyLimit)
90 { 83 {
91 << 84 G4cout << "G4PenelopeAnnihilationModel: low energy limit increased from " <<
92 if(fVerboseLevel > 0) { << 85 LowEnergyLimit()/eV << " eV to " << fIntrinsicLowEnergyLimit/eV << " eV" << G4endl;
93 G4cout << "Penelope Annihilation model is in << 86 SetLowEnergyLimit(fIntrinsicLowEnergyLimit);
94 << "Energy range: " <<
95 << LowEnergyLimit() / keV << " keV - <<
96 << HighEnergyLimit() / GeV << " GeV" <<
97 << G4endl; <<
98 } <<
99 } 87 }
100 << 88 if (HighEnergyLimit() > fIntrinsicHighEnergyLimit)
101 if(fIsInitialised) return; <<
102 fParticleChange = GetParticleChangeForGamma( <<
103 fIsInitialised = true; <<
104 } <<
105 <<
106 //....oooOO0OOooo........oooOO0OOooo........oo <<
107 void G4PenelopeAnnihilationModel::InitialiseLo <<
108 G4VEmModel* masterModel) <<
109 { <<
110 if (fVerboseLevel > 3) <<
111 G4cout << "Calling G4PenelopeAnnihilationM <<
112 <<
113 // <<
114 //Check that particle matches: one might hav <<
115 //for e+ and e-). <<
116 // <<
117 if (part == fParticle) <<
118 { 89 {
119 //Get the const table pointers from the << 90 G4cout << "G4PenelopeAnnihilationModel: high energy limit decreased from " <<
120 const G4PenelopeAnnihilationModel* theMo << 91 HighEnergyLimit()/GeV << " GeV to " << fIntrinsicHighEnergyLimit/GeV << " GeV" << G4endl;
121 static_cast<G4PenelopeAnnihilationMode << 92 SetHighEnergyLimit(fIntrinsicHighEnergyLimit);
122 <<
123 //Same verbosity for all workers, as the <<
124 fVerboseLevel = theModel->fVerboseLevel; <<
125 } 93 }
>> 94
>> 95 G4cout << "Penelope Annihilation model is initialized " << G4endl
>> 96 << "Energy range: "
>> 97 << LowEnergyLimit() / keV << " keV - "
>> 98 << HighEnergyLimit() / GeV << " GeV"
>> 99 << G4endl;
>> 100
>> 101 if(isInitialised) return;
>> 102
>> 103 if(pParticleChange)
>> 104 fParticleChange = reinterpret_cast<G4ParticleChangeForGamma*>(pParticleChange);
>> 105 else
>> 106 fParticleChange = new G4ParticleChangeForGamma();
>> 107 isInitialised = true;
126 } 108 }
127 109
128 //....oooOO0OOooo........oooOO0OOooo........oo 110 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
129 111
130 G4double G4PenelopeAnnihilationModel::ComputeC 112 G4double G4PenelopeAnnihilationModel::ComputeCrossSectionPerAtom(
131 const G 113 const G4ParticleDefinition*,
132 G 114 G4double energy,
133 G 115 G4double Z, G4double,
134 G 116 G4double, G4double)
135 { 117 {
136 if (fVerboseLevel > 3) << 118 if (verboseLevel > 3)
137 G4cout << "Calling ComputeCrossSectionPerA 119 G4cout << "Calling ComputeCrossSectionPerAtom() of G4PenelopeAnnihilationModel" <<
138 G4endl; 120 G4endl;
139 121
140 G4double cs = Z*ComputeCrossSectionPerElectr 122 G4double cs = Z*ComputeCrossSectionPerElectron(energy);
141 123
142 if (fVerboseLevel > 2) << 124 if (verboseLevel > 2)
143 G4cout << "Annihilation cross Section at " 125 G4cout << "Annihilation cross Section at " << energy/keV << " keV for Z=" << Z <<
144 " = " << cs/barn << " barn" << G4endl; 126 " = " << cs/barn << " barn" << G4endl;
145 return cs; 127 return cs;
146 } 128 }
147 129
148 //....oooOO0OOooo........oooOO0OOooo........oo 130 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
149 131
150 void G4PenelopeAnnihilationModel::SampleSecond 132 void G4PenelopeAnnihilationModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
151 const G4MaterialCutsCouple*, 133 const G4MaterialCutsCouple*,
152 const G4DynamicParticle* aDyna 134 const G4DynamicParticle* aDynamicPositron,
153 G4double, 135 G4double,
154 G4double) 136 G4double)
155 { 137 {
156 // 138 //
157 // Penelope model to sample final state for 139 // Penelope model to sample final state for positron annihilation.
158 // Target eletrons are assumed to be free an 140 // Target eletrons are assumed to be free and at rest. Binding effects enabling
159 // one-photon annihilation are neglected. 141 // one-photon annihilation are neglected.
160 // For annihilation at rest, two back-to-bac 142 // For annihilation at rest, two back-to-back photons are emitted, having energy of 511 keV
161 // and isotropic angular distribution. 143 // and isotropic angular distribution.
162 // For annihilation in flight, it is used th 144 // For annihilation in flight, it is used the theory from
163 // W. Heitler, The quantum theory of radiat 145 // W. Heitler, The quantum theory of radiation, Oxford University Press (1954)
164 // The two photons can have different energy 146 // The two photons can have different energy. The efficiency of the sampling algorithm
165 // of the photon energy from the dSigma/dE d 147 // of the photon energy from the dSigma/dE distribution is practically 100% for
166 // positrons of kinetic energy < 10 keV. It 148 // positrons of kinetic energy < 10 keV. It reaches a minimum (about 80%) at energy
167 // of about 10 MeV. 149 // of about 10 MeV.
168 // The angle theta is kinematically linked t 150 // The angle theta is kinematically linked to the photon energy, to ensure momentum
169 // conservation. The angle phi is sampled is 151 // conservation. The angle phi is sampled isotropically for the first gamma.
170 // 152 //
171 if (fVerboseLevel > 3) << 153 if (verboseLevel > 3)
172 G4cout << "Calling SamplingSecondaries() o 154 G4cout << "Calling SamplingSecondaries() of G4PenelopeAnnihilationModel" << G4endl;
173 155
174 G4double kineticEnergy = aDynamicPositron->G 156 G4double kineticEnergy = aDynamicPositron->GetKineticEnergy();
175 <<
176 // kill primary <<
177 fParticleChange->SetProposedKineticEnergy(0. <<
178 fParticleChange->ProposeTrackStatus(fStopAnd <<
179 157
180 if (kineticEnergy == 0.0) << 158 if (kineticEnergy == 0)
181 { 159 {
182 //Old AtRestDoIt 160 //Old AtRestDoIt
183 G4double cosTheta = -1.0+2.0*G4UniformRa 161 G4double cosTheta = -1.0+2.0*G4UniformRand();
184 G4double sinTheta = std::sqrt(1.0-cosThe 162 G4double sinTheta = std::sqrt(1.0-cosTheta*cosTheta);
185 G4double phi = twopi*G4UniformRand(); 163 G4double phi = twopi*G4UniformRand();
186 G4ThreeVector direction (sinTheta*std::c 164 G4ThreeVector direction (sinTheta*std::cos(phi),sinTheta*std::sin(phi),cosTheta);
187 G4DynamicParticle* firstGamma = new G4Dy 165 G4DynamicParticle* firstGamma = new G4DynamicParticle (G4Gamma::Gamma(),
188 direction, electron_mass_c2 166 direction, electron_mass_c2);
189 G4DynamicParticle* secondGamma = new G4D 167 G4DynamicParticle* secondGamma = new G4DynamicParticle (G4Gamma::Gamma(),
190 -direction, electron_mass_ 168 -direction, electron_mass_c2);
191 169
192 fvect->push_back(firstGamma); 170 fvect->push_back(firstGamma);
193 fvect->push_back(secondGamma); 171 fvect->push_back(secondGamma);
>> 172 fParticleChange->SetProposedKineticEnergy(0.);
>> 173 fParticleChange->ProposeTrackStatus(fStopAndKill);
194 return; 174 return;
195 } 175 }
196 176
197 //This is the "PostStep" case (annihilation 177 //This is the "PostStep" case (annihilation in flight)
198 G4ParticleMomentum positronDirection = 178 G4ParticleMomentum positronDirection =
199 aDynamicPositron->GetMomentumDirection(); 179 aDynamicPositron->GetMomentumDirection();
200 G4double gamma = 1.0 + std::max(kineticEnerg 180 G4double gamma = 1.0 + std::max(kineticEnergy,1.0*eV)/electron_mass_c2;
201 G4double gamma21 = std::sqrt(gamma*gamma-1); 181 G4double gamma21 = std::sqrt(gamma*gamma-1);
202 G4double ani = 1.0+gamma; 182 G4double ani = 1.0+gamma;
203 G4double chimin = 1.0/(ani+gamma21); 183 G4double chimin = 1.0/(ani+gamma21);
204 G4double rchi = (1.0-chimin)/chimin; 184 G4double rchi = (1.0-chimin)/chimin;
205 G4double gt0 = ani*ani-2.0; 185 G4double gt0 = ani*ani-2.0;
206 G4double test=0.0; 186 G4double test=0.0;
207 G4double epsilon = 0; 187 G4double epsilon = 0;
208 do{ 188 do{
209 epsilon = chimin*std::pow(rchi,G4UniformRa 189 epsilon = chimin*std::pow(rchi,G4UniformRand());
210 G4double reject = ani*ani*(1.0-epsilon)+2. 190 G4double reject = ani*ani*(1.0-epsilon)+2.0*gamma-(1.0/epsilon);
211 test = G4UniformRand()*gt0-reject; 191 test = G4UniformRand()*gt0-reject;
212 }while(test>0); 192 }while(test>0);
213 193
214 G4double totalAvailableEnergy = kineticEnerg 194 G4double totalAvailableEnergy = kineticEnergy + 2.0*electron_mass_c2;
215 G4double photon1Energy = epsilon*totalAvaila 195 G4double photon1Energy = epsilon*totalAvailableEnergy;
216 G4double photon2Energy = (1.0-epsilon)*total 196 G4double photon2Energy = (1.0-epsilon)*totalAvailableEnergy;
217 G4double cosTheta1 = (ani-1.0/epsilon)/gamma 197 G4double cosTheta1 = (ani-1.0/epsilon)/gamma21;
218 G4double cosTheta2 = (ani-1.0/(1.0-epsilon)) 198 G4double cosTheta2 = (ani-1.0/(1.0-epsilon))/gamma21;
219 199
>> 200 //G4double localEnergyDeposit = 0.;
>> 201
220 G4double sinTheta1 = std::sqrt(1.-cosTheta1* 202 G4double sinTheta1 = std::sqrt(1.-cosTheta1*cosTheta1);
221 G4double phi1 = twopi * G4UniformRand(); 203 G4double phi1 = twopi * G4UniformRand();
222 G4double dirx1 = sinTheta1 * std::cos(phi1); 204 G4double dirx1 = sinTheta1 * std::cos(phi1);
223 G4double diry1 = sinTheta1 * std::sin(phi1); 205 G4double diry1 = sinTheta1 * std::sin(phi1);
224 G4double dirz1 = cosTheta1; 206 G4double dirz1 = cosTheta1;
225 207
226 G4double sinTheta2 = std::sqrt(1.-cosTheta2* 208 G4double sinTheta2 = std::sqrt(1.-cosTheta2*cosTheta2);
227 G4double phi2 = phi1+pi; 209 G4double phi2 = phi1+pi;
228 G4double dirx2 = sinTheta2 * std::cos(phi2); 210 G4double dirx2 = sinTheta2 * std::cos(phi2);
229 G4double diry2 = sinTheta2 * std::sin(phi2); 211 G4double diry2 = sinTheta2 * std::sin(phi2);
230 G4double dirz2 = cosTheta2; 212 G4double dirz2 = cosTheta2;
231 213
232 G4ThreeVector photon1Direction (dirx1,diry1, 214 G4ThreeVector photon1Direction (dirx1,diry1,dirz1);
233 photon1Direction.rotateUz(positronDirection) 215 photon1Direction.rotateUz(positronDirection);
234 // create G4DynamicParticle object for the p 216 // create G4DynamicParticle object for the particle1
235 G4DynamicParticle* aParticle1= new G4Dynamic 217 G4DynamicParticle* aParticle1= new G4DynamicParticle (G4Gamma::Gamma(),
236 photon1Direction, 218 photon1Direction,
237 photon1Energy); 219 photon1Energy);
238 fvect->push_back(aParticle1); 220 fvect->push_back(aParticle1);
239 221
240 G4ThreeVector photon2Direction(dirx2,diry2,d 222 G4ThreeVector photon2Direction(dirx2,diry2,dirz2);
241 photon2Direction.rotateUz(positronDirection) 223 photon2Direction.rotateUz(positronDirection);
242 // create G4DynamicParticle object for the p << 224 // create G4DynamicParticle object for the particle2
243 G4DynamicParticle* aParticle2= new G4Dynamic 225 G4DynamicParticle* aParticle2= new G4DynamicParticle (G4Gamma::Gamma(),
244 photon2Direction, 226 photon2Direction,
245 photon2Energy); 227 photon2Energy);
246 fvect->push_back(aParticle2); 228 fvect->push_back(aParticle2);
>> 229 fParticleChange->SetProposedKineticEnergy(0.);
>> 230 fParticleChange->ProposeTrackStatus(fStopAndKill);
247 231
248 if (fVerboseLevel > 1) << 232 if (verboseLevel > 1)
249 { 233 {
250 G4cout << "----------------------------- 234 G4cout << "-----------------------------------------------------------" << G4endl;
251 G4cout << "Energy balance from G4Penelop 235 G4cout << "Energy balance from G4PenelopeAnnihilation" << G4endl;
252 G4cout << "Kinetic positron energy: " << 236 G4cout << "Kinetic positron energy: " << kineticEnergy/keV << " keV" << G4endl;
253 G4cout << "Total available energy: " << 237 G4cout << "Total available energy: " << totalAvailableEnergy/keV << " keV " << G4endl;
254 G4cout << "----------------------------- 238 G4cout << "-----------------------------------------------------------" << G4endl;
255 G4cout << "Photon energy 1: " << photon1 239 G4cout << "Photon energy 1: " << photon1Energy/keV << " keV" << G4endl;
256 G4cout << "Photon energy 2: " << photon2 240 G4cout << "Photon energy 2: " << photon2Energy/keV << " keV" << G4endl;
257 G4cout << "Total final state: " << (phot 241 G4cout << "Total final state: " << (photon1Energy+photon2Energy)/keV <<
258 " keV" << G4endl; 242 " keV" << G4endl;
259 G4cout << "----------------------------- 243 G4cout << "-----------------------------------------------------------" << G4endl;
260 } 244 }
261 if (fVerboseLevel > 0) << 245 if (verboseLevel > 0)
262 { << 246 {
>> 247
263 G4double energyDiff = std::fabs(totalAva 248 G4double energyDiff = std::fabs(totalAvailableEnergy-photon1Energy-photon2Energy);
264 if (energyDiff > 0.05*keV) 249 if (energyDiff > 0.05*keV)
265 G4cout << "Warning from G4PenelopeAnnihilati 250 G4cout << "Warning from G4PenelopeAnnihilation: problem with energy conservation: " <<
266 (photon1Energy+photon2Energy)/keV << 251 (photon1Energy+photon2Energy)/keV <<
267 " keV (final) vs. " << 252 " keV (final) vs. " <<
268 totalAvailableEnergy/keV << " keV (initial 253 totalAvailableEnergy/keV << " keV (initial)" << G4endl;
269 } 254 }
270 return; 255 return;
271 } 256 }
272 257
273 //....oooOO0OOooo........oooOO0OOooo........oo 258 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
274 259
275 G4double G4PenelopeAnnihilationModel:: Compute 260 G4double G4PenelopeAnnihilationModel:: ComputeCrossSectionPerElectron(G4double energy)
276 { 261 {
277 // 262 //
278 // Penelope model to calculate cross section 263 // Penelope model to calculate cross section for positron annihilation.
279 // The annihilation cross section per electr 264 // The annihilation cross section per electron is calculated according
280 // to the Heitler formula 265 // to the Heitler formula
281 // W. Heitler, The quantum theory of radiat 266 // W. Heitler, The quantum theory of radiation, Oxford University Press (1954)
282 // in the assumptions of electrons free and 267 // in the assumptions of electrons free and at rest.
283 // 268 //
284 G4double gamma = 1.0+std::max(energy,1.0*eV) 269 G4double gamma = 1.0+std::max(energy,1.0*eV)/electron_mass_c2;
285 G4double gamma2 = gamma*gamma; 270 G4double gamma2 = gamma*gamma;
286 G4double f2 = gamma2-1.0; 271 G4double f2 = gamma2-1.0;
287 G4double f1 = std::sqrt(f2); 272 G4double f1 = std::sqrt(f2);
288 G4double crossSection = fPielr2*((gamma2+4.0 << 273 G4double crossSection = fPielr2*((gamma2+4.0*gamma+1.0)*std::log(gamma+f1)/f2
289 - (gamma+3.0)/f1)/(gamma+1.0); 274 - (gamma+3.0)/f1)/(gamma+1.0);
290 return crossSection; 275 return crossSection;
291 } <<
292 <<
293 //....oooOO0OOooo........oooOO0OOooo........oo <<
294 <<
295 void G4PenelopeAnnihilationModel::SetParticle( <<
296 { <<
297 if(!fParticle) { <<
298 fParticle = p; <<
299 } <<
300 } 276 }
301 277