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25 // 25 //
>> 26 // $Id: G4UniversalFluctuation.cc,v 1.13 2007/03/21 15:23:45 urban Exp $
>> 27 // GEANT4 tag $Name: geant4-08-03 $
26 // 28 //
27 // ------------------------------------------- 29 // -------------------------------------------------------------------
28 // 30 //
29 // GEANT4 Class file 31 // GEANT4 Class file
30 // 32 //
31 // 33 //
32 // File name: G4UniversalFluctuation 34 // File name: G4UniversalFluctuation
33 // 35 //
34 // Author: V. Ivanchenko for Laszlo Urb << 36 // Author: Vladimir Ivanchenko
35 // 37 //
36 // Creation date: 03.01.2002 38 // Creation date: 03.01.2002
37 // 39 //
38 // Modifications: 40 // Modifications:
39 // 41 //
40 // << 42 // 28-12-02 add method Dispersion (V.Ivanchenko)
>> 43 // 07-02-03 change signature (V.Ivanchenko)
>> 44 // 13-02-03 Add name (V.Ivanchenko)
>> 45 // 16-10-03 Changed interface to Initialisation (V.Ivanchenko)
>> 46 // 07-11-03 Fix problem of rounding of double in G4UniversalFluctuations
>> 47 // 06-02-04 Add control on big sigma > 2*meanLoss (V.Ivanchenko)
>> 48 // 26-04-04 Comment out the case of very small step (V.Ivanchenko)
>> 49 // 07-02-05 define problim = 5.e-3 (mma)
>> 50 // 03-05-05 conditions of Gaussian fluctuation changed (bugfix)
>> 51 // + smearing for very small loss (L.Urban)
>> 52 // 03-10-05 energy dependent rate -> cut dependence of the
>> 53 // distribution is much weaker (L.Urban)
>> 54 // 17-10-05 correction for very small loss (L.Urban)
>> 55 // 20-03-07 'GLANDZ' part rewritten completely, no 'very small loss'
>> 56 // regime any more (L.Urban)
>> 57 // 21-03-07 optimization in ionization part (L.Urban)
>> 58 //
41 59
42 //....oooOO0OOooo........oooOO0OOooo........oo 60 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
43 //....oooOO0OOooo........oooOO0OOooo........oo 61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
44 62
45 #include "G4UniversalFluctuation.hh" 63 #include "G4UniversalFluctuation.hh"
46 #include "G4PhysicalConstants.hh" <<
47 #include "G4SystemOfUnits.hh" <<
48 #include "Randomize.hh" 64 #include "Randomize.hh"
49 #include "G4Poisson.hh" 65 #include "G4Poisson.hh"
>> 66 #include "G4Step.hh"
50 #include "G4Material.hh" 67 #include "G4Material.hh"
51 #include "G4MaterialCutsCouple.hh" <<
52 #include "G4DynamicParticle.hh" 68 #include "G4DynamicParticle.hh"
53 #include "G4ParticleDefinition.hh" 69 #include "G4ParticleDefinition.hh"
54 #include "G4Log.hh" <<
55 70
56 //....oooOO0OOooo........oooOO0OOooo........oo 71 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
57 72
>> 73 using namespace std;
>> 74
58 G4UniversalFluctuation::G4UniversalFluctuation 75 G4UniversalFluctuation::G4UniversalFluctuation(const G4String& nam)
59 :G4VEmFluctuationModel(nam), 76 :G4VEmFluctuationModel(nam),
60 minLoss(10.*CLHEP::eV) << 77 particle(0),
>> 78 minNumberInteractionsBohr(10.0),
>> 79 theBohrBeta2(50.0*keV/proton_mass_c2),
>> 80 minLoss(10.*eV),
>> 81 nmaxCont1(4.),
>> 82 nmaxCont2(16.)
61 { 83 {
62 rndmarray = new G4double[sizearray]; << 84 lastMaterial = 0;
63 } 85 }
64 86
65 //....oooOO0OOooo........oooOO0OOooo........oo 87 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
66 88
67 G4UniversalFluctuation::~G4UniversalFluctuatio 89 G4UniversalFluctuation::~G4UniversalFluctuation()
68 { << 90 {}
69 delete [] rndmarray; <<
70 } <<
71 91
72 //....oooOO0OOooo........oooOO0OOooo........oo 92 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
73 93
74 void G4UniversalFluctuation::InitialiseMe(cons 94 void G4UniversalFluctuation::InitialiseMe(const G4ParticleDefinition* part)
75 { 95 {
76 particle = part; << 96 particle = part;
77 particleMass = part->GetPDGMass(); << 97 particleMass = part->GetPDGMass();
78 const G4double q = part->GetPDGCharge()/CLHE << 98 G4double q = part->GetPDGCharge()/eplus;
79 << 99 chargeSquare = q*q;
80 // Derived quantities <<
81 m_Inv_particleMass = 1.0 / particleMass; <<
82 m_massrate = CLHEP::electron_mass_c2 * m_Inv <<
83 chargeSquare = q*q; <<
84 } 100 }
85 101
86 //....oooOO0OOooo........oooOO0OOooo........oo 102 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
87 103
88 G4double << 104 G4double G4UniversalFluctuation::SampleFluctuations(const G4Material* material,
89 G4UniversalFluctuation::SampleFluctuations(con << 105 const G4DynamicParticle* dp,
90 con << 106 G4double& tmax,
91 con << 107 G4double& length,
92 con << 108 G4double& meanLoss)
93 con <<
94 con <<
95 { 109 {
96 // Calculate actual loss from the mean loss. << 110 // Calculate actual loss from the mean loss.
97 // The model used to get the fluctuations is << 111 // The model used to get the fluctuations is essentially the same
98 // as in Glandz in Geant3 (Cern program libr << 112 // as in Glandz in Geant3 (Cern program library W5013, phys332).
99 // L. Urban et al. NIM A362, p.416 (1995) an << 113 // L. Urban et al. NIM A362, p.416 (1995) and Geant4 Physics Reference Manual
100 114
101 // shortcut for very small loss or from a st << 115 // shortcut for very very small loss (out of validity of the model)
102 // (out of validity of the model) <<
103 // 116 //
104 if (averageLoss < minLoss) { return averageL << 117 if (meanLoss < minLoss) return meanLoss;
105 meanLoss = averageLoss; <<
106 const G4double tkin = dp->GetKineticEnergy( <<
107 //G4cout<< "Emean= "<< meanLoss<< " tmax= "< <<
108 <<
109 if(dp->GetDefinition() != particle) { Initia <<
110 <<
111 CLHEP::HepRandomEngine* rndmEngineF = G4Rand <<
112 <<
113 const G4double gam = tkin * m_Inv_particle <<
114 const G4double gam2 = gam*gam; <<
115 const G4double beta = dp->GetBeta(); <<
116 const G4double beta2 = beta*beta; <<
117 118
118 G4double loss(0.), siga(0.); << 119 if(!particle) InitialiseMe(dp->GetDefinition());
119 120
120 const G4Material* material = couple->GetMate << 121 G4double tau = dp->GetKineticEnergy()/particleMass;
>> 122 G4double gam = tau + 1.0;
>> 123 G4double gam2 = gam*gam;
>> 124 G4double beta2 = tau*(tau + 2.0)/gam2;
>> 125
>> 126 G4double loss(0.), siga(0.);
121 127
122 // Gaussian regime 128 // Gaussian regime
123 // for heavy particles only and conditions 129 // for heavy particles only and conditions
124 // for Gauusian fluct. has been changed 130 // for Gauusian fluct. has been changed
125 // 131 //
126 if (particleMass > CLHEP::electron_mass_c2 & << 132 if ((particleMass > electron_mass_c2) &&
127 meanLoss >= minNumberInteractionsBohr*tc << 133 (meanLoss >= minNumberInteractionsBohr*tmax))
128 << 134 {
129 siga = std::sqrt((tmax/beta2 - 0.5*tcut)*C << 135 G4double massrate = electron_mass_c2/particleMass ;
130 length*chargeSquare*mate << 136 G4double tmaxkine = 2.*electron_mass_c2*beta2*gam2/
131 const G4double sn = meanLoss/siga; << 137 (1.+massrate*(2.*gam+massrate)) ;
132 << 138 if (tmaxkine <= 2.*tmax)
133 // thick target case << 139 {
134 if (sn >= 2.0) { << 140 electronDensity = material->GetElectronDensity();
135 << 141 siga = (1.0/beta2 - 0.5) * twopi_mc2_rcl2 * tmax * length
136 const G4double twomeanLoss = meanLoss + << 142 * electronDensity * chargeSquare;
137 do { << 143 siga = sqrt(siga);
138 loss = G4RandGauss::shoot(rndmEngineF, meanL << 144 G4double twomeanLoss = meanLoss + meanLoss;
139 // Loop checking, 03-Aug-2015, Vladimir Ivan << 145 if (twomeanLoss < siga) {
140 } while (0.0 > loss || twomeanLoss < lo << 146 G4double x;
141 << 147 do {
142 // Gamma distribution << 148 loss = twomeanLoss*G4UniformRand();
143 } else { << 149 x = (loss - meanLoss)/siga;
144 << 150 } while (1.0 - 0.5*x*x < G4UniformRand());
145 const G4double neff = sn*sn; << 151 } else {
146 loss = meanLoss*G4RandGamma::shoot(rndmE << 152 do {
>> 153 loss = G4RandGauss::shoot(meanLoss,siga);
>> 154 } while (loss < 0. || loss > twomeanLoss);
>> 155 }
>> 156 return loss;
147 } 157 }
148 //G4cout << "Gauss: " << loss << G4endl; <<
149 return loss; <<
150 } 158 }
151 159
152 auto ioni = material->GetIonisation(); << 160 // Glandz regime : initialisation
153 e0 = ioni->GetEnergy0fluct(); << 161 //
154 << 162 if (material != lastMaterial) {
155 // very small step or low-density material << 163 f1Fluct = material->GetIonisation()->GetF1fluct();
156 if(tcut <= e0) { return meanLoss; } << 164 f2Fluct = material->GetIonisation()->GetF2fluct();
157 << 165 e1Fluct = material->GetIonisation()->GetEnergy1fluct();
158 ipotFluct = ioni->GetMeanExcitationEnergy(); << 166 e2Fluct = material->GetIonisation()->GetEnergy2fluct();
159 ipotLogFluct = ioni->GetLogMeanExcEnergy(); << 167 e1LogFluct = material->GetIonisation()->GetLogEnergy1fluct();
>> 168 e2LogFluct = material->GetIonisation()->GetLogEnergy2fluct();
>> 169 ipotFluct = material->GetIonisation()->GetMeanExcitationEnergy();
>> 170 ipotLogFluct = material->GetIonisation()->GetLogMeanExcEnergy();
>> 171 e0 = material->GetIonisation()->GetEnergy0fluct();
>> 172 lastMaterial = material;
>> 173 }
160 174
161 // width correction for small cuts << 175 G4double a1 = 0. , a2 = 0., a3 = 0. ;
162 const G4double scaling = std::min(1.+0.5*CLH <<
163 meanLoss /= scaling; <<
164 176
165 w2 = (tcut > ipotFluct) ? << 177 // cut and material dependent rate
166 G4Log(2.*CLHEP::electron_mass_c2*beta2*gam << 178 G4double rate = 1.0;
167 return SampleGlandz(rndmEngineF, material, t << 179 if(tmax > ipotFluct) {
168 } << 180 G4double w2 = log(2.*electron_mass_c2*beta2*gam2)-beta2;
>> 181
>> 182 if(w2 > ipotLogFluct && w2 > e2LogFluct) {
>> 183
>> 184 rate = 0.03+0.23*log(log(tmax/ipotFluct));
>> 185 G4double C = meanLoss*(1.-rate)/(w2-ipotLogFluct);
>> 186 a1 = C*f1Fluct*(w2-e1LogFluct)/e1Fluct;
>> 187 a2 = C*f2Fluct*(w2-e2LogFluct)/e2Fluct;
>> 188 }
>> 189 }
169 190
170 //....oooOO0OOooo........oooOO0OOooo........oo << 191 G4double w1 = tmax/e0;
>> 192 if(tmax > e0)
>> 193 a3 = rate*meanLoss*(tmax-e0)/(e0*tmax*log(w1));
171 194
172 G4double << 195 //'nearly' Gaussian fluctuation if a1>nmaxCont2&&a2>nmaxCont2&&a3>nmaxCont2
173 G4UniversalFluctuation::SampleGlandz(CLHEP::He <<
174 const G4M <<
175 const G4d <<
176 { <<
177 G4double a1(0.0), a3(0.0); <<
178 G4double loss = 0.0; <<
179 G4double e1 = ipotFluct; <<
180 <<
181 if(tcut > e1) { <<
182 a1 = meanLoss*(1.-rate)/e1; <<
183 if(a1 < a0) { <<
184 const G4double fwnow = 0.1+(fw-0.1)*std: <<
185 a1 /= fwnow; <<
186 e1 *= fwnow; <<
187 } else { <<
188 a1 /= fw; <<
189 e1 *= fw; <<
190 } <<
191 } <<
192 <<
193 const G4double w1 = tcut/e0; <<
194 a3 = rate*meanLoss*(tcut - e0)/(e0*tcut*G4Lo <<
195 if(a1 <= 0.) { a3 /= rate; } <<
196 <<
197 //'nearly' Gaussian fluctuation if a1>nmaxCo <<
198 G4double emean = 0.; 196 G4double emean = 0.;
199 G4double sig2e = 0.; << 197 G4double sig2e = 0., sige = 0.;
200 << 198 G4double p1 = 0., p2 = 0., p3 = 0.;
>> 199
201 // excitation of type 1 200 // excitation of type 1
202 if(a1 > 0.0) { AddExcitation(rndmEngineF, a1 << 201 if(a1 > nmaxCont2)
>> 202 {
>> 203 emean += a1*e1Fluct;
>> 204 sig2e += a1*e1Fluct*e1Fluct;
>> 205 }
>> 206 else if(a1 > 0.)
>> 207 {
>> 208 p1 = G4double(G4Poisson(a1));
>> 209 loss += p1*e1Fluct;
>> 210 if(p1 > 0.)
>> 211 loss += (1.-2.*G4UniformRand())*e1Fluct;
>> 212 }
203 213
204 if(sig2e > 0.0) { SampleGauss(rndmEngineF, e << 214 // excitation of type 2
>> 215 if(a2 > nmaxCont2)
>> 216 {
>> 217 emean += a2*e2Fluct;
>> 218 sig2e += a2*e2Fluct*e2Fluct;
>> 219 }
>> 220 else if(a2 > 0.)
>> 221 {
>> 222 p2 = G4double(G4Poisson(a2));
>> 223 loss += p2*e2Fluct;
>> 224 if(p2 > 0.)
>> 225 loss += (1.-2.*G4UniformRand())*e2Fluct;
>> 226 }
205 227
206 // ionisation 228 // ionisation
207 if(a3 > 0.) { << 229 G4double lossc = 0.;
208 emean = 0.; << 230 if(a3 > 0.)
209 sig2e = 0.; << 231 {
210 G4double p3 = a3; << 232 p3 = a3;
211 G4double alfa = 1.; 233 G4double alfa = 1.;
212 if(a3 > nmaxCont) { << 234 if(a3 > nmaxCont2)
213 alfa = w1*(nmaxCont+a3)/(w1*nmaxCont+a3) << 235 {
214 const G4double alfa1 = alfa*G4Log(alfa) << 236 alfa = w1*(nmaxCont2+a3)/(w1*nmaxCont2+a3);
215 const G4double namean = a3*w1*(alfa-1.)/ << 237 G4double alfa1 = alfa*log(alfa)/(alfa-1.);
216 emean += namean*e0*alfa1; << 238 G4double namean = a3*w1*(alfa-1.)/((w1-1.)*alfa);
217 sig2e += e0*e0*namean*(alfa-alfa1*alfa1) << 239 emean += namean*e0*alfa1;
218 p3 = a3 - namean; << 240 sig2e += e0*e0*namean*(alfa-alfa1*alfa1);
>> 241 p3 = a3-namean;
219 } 242 }
220 << 243
221 const G4double w3 = alfa*e0; << 244 G4double w2 = alfa*e0;
222 if(tcut > w3) { << 245 G4double w = (tmax-w2)/tmax;
223 const G4double w = (tcut-w3)/tcut; << 246 G4double scale = 1.;
224 const G4int nnb = (G4int)G4Poisson(p3); << 247 G4int nb = 0;
225 if(nnb > 0) { << 248 if(p3 < nmaxCont2)
226 if(nnb > sizearray) { << 249 nb = G4Poisson(p3);
227 sizearray = nnb; << 250 else
228 delete [] rndmarray; << 251 {
229 rndmarray = new G4double[nnb]; << 252 nb = G4Poisson(nmaxCont2);
230 } << 253 scale = p3/nmaxCont2;
231 rndmEngineF->flatArray(nnb, rndmarray) <<
232 for (G4int k=0; k<nnb; ++k) { loss += <<
233 } <<
234 } 254 }
235 if(sig2e > 0.0) { SampleGauss(rndmEngineF, << 255 if(nb > 0)
>> 256 for (G4int k=0; k<nb; k++) lossc += scale*w2/(1.-w*G4UniformRand());
236 } 257 }
237 //G4cout << "### loss=" << loss << G4endl; << 258
>> 259 if(emean > 0.)
>> 260 {
>> 261 sige = sqrt(sig2e);
>> 262 loss += max(0.,G4RandGauss::shoot(emean,sige));
>> 263 }
>> 264
>> 265 loss += lossc;
>> 266
238 return loss; 267 return loss;
>> 268
239 } 269 }
240 270
241 //....oooOO0OOooo........oooOO0OOooo........oo 271 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
242 272
243 273
244 G4double G4UniversalFluctuation::Dispersion( 274 G4double G4UniversalFluctuation::Dispersion(
245 const G4Material* ma 275 const G4Material* material,
246 const G4DynamicParti 276 const G4DynamicParticle* dp,
247 const G4double tcut, << 277 G4double& tmax,
248 const G4double tmax, << 278 G4double& length)
249 const G4double lengt <<
250 { 279 {
251 if(dp->GetDefinition() != particle) { Initia << 280 if(!particle) InitialiseMe(dp->GetDefinition());
252 const G4double beta = dp->GetBeta(); <<
253 return (tmax/(beta*beta) - 0.5*tcut) * CLHEP <<
254 * material->GetElectronDensity() * chargeS <<
255 } <<
256 281
257 //....oooOO0OOooo........oooOO0OOooo........oo << 282 electronDensity = material->GetElectronDensity();
258 283
259 void << 284 G4double gam = (dp->GetKineticEnergy())/particleMass + 1.0;
260 G4UniversalFluctuation::SetParticleAndCharge(c << 285 G4double beta2 = 1.0 - 1.0/(gam*gam);
261 G << 286
262 { << 287 G4double siga = (1.0/beta2 - 0.5) * twopi_mc2_rcl2 * tmax * length
263 if(part != particle) { << 288 * electronDensity * chargeSquare;
264 particle = part; << 289
265 particleMass = part->GetPDGMass(); << 290 return siga;
266 <<
267 // Derived quantities <<
268 m_Inv_particleMass = 1.0 / particleMass; <<
269 m_massrate = CLHEP::electron_mass_c2 * m_I <<
270 } <<
271 chargeSquare = q2; <<
272 } 291 }
273 292
274 //....oooOO0OOooo........oooOO0OOooo........oo 293 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
275 294