| Geant4 Cross Reference |
1 // 1 //
2 // ******************************************* 2 // ********************************************************************
3 // * License and Disclaimer 3 // * License and Disclaimer *
4 // * 4 // * *
5 // * The Geant4 software is copyright of th 5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided 6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License 7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/ 8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. 9 // * include a list of copyright holders. *
10 // * 10 // * *
11 // * Neither the authors of this software syst 11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing fin 12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warran 13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assum 14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file 15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitatio 16 // * for the full disclaimer and the limitation of liability. *
17 // * 17 // * *
18 // * This code implementation is the result 18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboratio 19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distri 20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you ag 21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publicati 22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Sof 23 // * acceptance of all terms of the Geant4 Software license. *
24 // ******************************************* 24 // ********************************************************************
25 // 25 //
>> 26 // $Id: G4UniversalFluctuation.cc,v 1.8 2006/06/29 19:53:32 gunter Exp $
>> 27 // GEANT4 tag $Name: geant4-08-01-patch-01 $
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 //
41 56
42 //....oooOO0OOooo........oooOO0OOooo........oo 57 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
43 //....oooOO0OOooo........oooOO0OOooo........oo 58 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
44 59
45 #include "G4UniversalFluctuation.hh" 60 #include "G4UniversalFluctuation.hh"
46 #include "G4PhysicalConstants.hh" <<
47 #include "G4SystemOfUnits.hh" <<
48 #include "Randomize.hh" 61 #include "Randomize.hh"
49 #include "G4Poisson.hh" 62 #include "G4Poisson.hh"
>> 63 #include "G4Step.hh"
50 #include "G4Material.hh" 64 #include "G4Material.hh"
51 #include "G4MaterialCutsCouple.hh" <<
52 #include "G4DynamicParticle.hh" 65 #include "G4DynamicParticle.hh"
53 #include "G4ParticleDefinition.hh" 66 #include "G4ParticleDefinition.hh"
54 #include "G4Log.hh" <<
55 67
56 //....oooOO0OOooo........oooOO0OOooo........oo 68 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
57 69
>> 70 using namespace std;
>> 71
58 G4UniversalFluctuation::G4UniversalFluctuation 72 G4UniversalFluctuation::G4UniversalFluctuation(const G4String& nam)
59 :G4VEmFluctuationModel(nam), 73 :G4VEmFluctuationModel(nam),
60 minLoss(10.*CLHEP::eV) << 74 particle(0),
>> 75 minNumberInteractionsBohr(10.0),
>> 76 theBohrBeta2(50.0*keV/proton_mass_c2),
>> 77 minLoss(10.*eV),
>> 78 problim(5.e-3),
>> 79 alim(10.),
>> 80 nmaxCont1(4.),
>> 81 nmaxCont2(16.)
61 { 82 {
62 rndmarray = new G4double[sizearray]; << 83 sumalim = -log(problim);
>> 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());
>> 120
>> 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;
119 125
120 const G4Material* material = couple->GetMate << 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 lastMaterial = material;
>> 172 }
160 173
161 // width correction for small cuts << 174 G4double a1 = 0. , a2 = 0., a3 = 0. ;
162 const G4double scaling = std::min(1.+0.5*CLH << 175 G4double p1,p2,p3;
163 meanLoss /= scaling; << 176 // cut and material dependent rate --------------------------------
164 << 177 G4double rate = 0.173+0.027*log(tmax/ipotFluct) ;
165 w2 = (tcut > ipotFluct) ? << 178 if(rate < 0.) rate = 0. ;
166 G4Log(2.*CLHEP::electron_mass_c2*beta2*gam << 179 if(rate > 1.) rate = 1. ;
167 return SampleGlandz(rndmEngineF, material, t << 180
168 } << 181 G4double w1 = tmax/ipotFluct;
>> 182 G4double w2 = log(2.*electron_mass_c2*beta2*gam2)-beta2;
>> 183
>> 184 if(w2 > ipotLogFluct)
>> 185 {
>> 186 G4double C = meanLoss*(1.-rate)/(w2-ipotLogFluct);
>> 187 a1 = C*f1Fluct*(w2-e1LogFluct)/e1Fluct;
>> 188 a2 = C*f2Fluct*(w2-e2LogFluct)/e2Fluct;
>> 189 if(a2 < 0.)
>> 190 {
>> 191 a1 = 0. ;
>> 192 a2 = 0. ;
>> 193 rate = 1. ;
>> 194 }
>> 195 }
>> 196 else
>> 197 {
>> 198 rate = 1. ;
>> 199 }
169 200
170 //....oooOO0OOooo........oooOO0OOooo........oo << 201 if(tmax > ipotFluct)
>> 202 a3 = rate*meanLoss*(tmax-ipotFluct)/(ipotFluct*tmax*log(w1));
171 203
172 G4double << 204 G4double suma = a1+a2+a3;
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; } <<
196 205
197 //'nearly' Gaussian fluctuation if a1>nmaxCo << 206 // Glandz regime
198 G4double emean = 0.; << 207 //
199 G4double sig2e = 0.; << 208 if (suma > sumalim)
200 << 209 {
201 // excitation of type 1 << 210 p1 = 0., p2 = 0 ;
202 if(a1 > 0.0) { AddExcitation(rndmEngineF, a1 << 211 if((a1+a2) > 0.)
203 << 212 {
204 if(sig2e > 0.0) { SampleGauss(rndmEngineF, e << 213 // excitation type 1
205 << 214 if (a1>alim) {
206 // ionisation << 215 siga=sqrt(a1) ;
207 if(a3 > 0.) { << 216 p1 = max(0.,G4RandGauss::shoot(a1,siga)+0.5);
208 emean = 0.; << 217 } else {
209 sig2e = 0.; << 218 p1 = G4double(G4Poisson(a1));
210 G4double p3 = a3; << 219 }
211 G4double alfa = 1.; << 220
212 if(a3 > nmaxCont) { << 221 // excitation type 2
213 alfa = w1*(nmaxCont+a3)/(w1*nmaxCont+a3) << 222 if (a2>alim) {
214 const G4double alfa1 = alfa*G4Log(alfa) << 223 siga=sqrt(a2) ;
215 const G4double namean = a3*w1*(alfa-1.)/ << 224 p2 = max(0.,G4RandGauss::shoot(a2,siga)+0.5);
216 emean += namean*e0*alfa1; << 225 } else {
217 sig2e += e0*e0*namean*(alfa-alfa1*alfa1) << 226 p2 = G4double(G4Poisson(a2));
218 p3 = a3 - namean; << 227 }
>> 228
>> 229 loss = p1*e1Fluct+p2*e2Fluct;
>> 230
>> 231 // smearing to avoid unphysical peaks
>> 232 if (p2 > 0.)
>> 233 loss += (1.-2.*G4UniformRand())*e2Fluct;
>> 234 else if (loss>0.)
>> 235 loss += (1.-2.*G4UniformRand())*e1Fluct;
>> 236 if (loss < 0.) loss = 0.0;
219 } 237 }
220 238
221 const G4double w3 = alfa*e0; << 239 // ionisation
222 if(tcut > w3) { << 240 if (a3 > 0.) {
223 const G4double w = (tcut-w3)/tcut; << 241 if (a3>alim) {
224 const G4int nnb = (G4int)G4Poisson(p3); << 242 siga=sqrt(a3) ;
225 if(nnb > 0) { << 243 p3 = max(0.,G4RandGauss::shoot(a3,siga)+0.5);
226 if(nnb > sizearray) { << 244 } else {
227 sizearray = nnb; << 245 p3 = G4double(G4Poisson(a3));
228 delete [] rndmarray; <<
229 rndmarray = new G4double[nnb]; <<
230 } <<
231 rndmEngineF->flatArray(nnb, rndmarray) <<
232 for (G4int k=0; k<nnb; ++k) { loss += <<
233 } 246 }
>> 247 G4double lossc = 0.;
>> 248 if (p3 > 0) {
>> 249 G4double na = 0.;
>> 250 G4double alfa = 1.;
>> 251 if (p3 > nmaxCont2) {
>> 252 G4double rfac = p3/(nmaxCont2+p3);
>> 253 G4double namean = p3*rfac;
>> 254 G4double sa = nmaxCont1*rfac;
>> 255 na = G4RandGauss::shoot(namean,sa);
>> 256 if (na > 0.) {
>> 257 alfa = w1*(nmaxCont2+p3)/(w1*nmaxCont2+p3);
>> 258 G4double alfa1 = alfa*log(alfa)/(alfa-1.);
>> 259 G4double ea = na*ipotFluct*alfa1;
>> 260 G4double sea = ipotFluct*sqrt(na*(alfa-alfa1*alfa1));
>> 261 lossc += G4RandGauss::shoot(ea,sea);
>> 262 }
>> 263 }
>> 264
>> 265 if (p3 > na) {
>> 266 w2 = alfa*ipotFluct;
>> 267 G4double w = (tmax-w2)/tmax;
>> 268 G4int nb = G4int(p3-na);
>> 269 for (G4int k=0; k<nb; k++) lossc += w2/(1.-w*G4UniformRand());
>> 270 }
>> 271 }
>> 272 loss += lossc;
234 } 273 }
235 if(sig2e > 0.0) { SampleGauss(rndmEngineF, << 274 return loss;
236 } 275 }
237 //G4cout << "### loss=" << loss << G4endl; << 276
238 return loss; << 277 // suma < sumalim; very small energy loss;
>> 278 //
>> 279 G4double e0 = material->GetIonisation()->GetEnergy0fluct();
>> 280
>> 281 if(tmax <= e0) return meanLoss;
>> 282 else a3 = meanLoss*(tmax-e0)/(tmax*e0*log(tmax/e0));
>> 283
>> 284 if (a3 > alim)
>> 285 {
>> 286 siga=sqrt(a3);
>> 287 p3 = max(0.,G4RandGauss::shoot(a3,siga)+0.5);
>> 288 } else {
>> 289 p3 = G4double(G4Poisson(a3));
>> 290 }
>> 291 if (p3 > 0.) {
>> 292 G4double w = (tmax-e0)/tmax;
>> 293 G4double corrfac = 1.;
>> 294 if (p3 > nmaxCont2) {
>> 295 corrfac = p3/nmaxCont2;
>> 296 p3 = nmaxCont2;
>> 297 }
>> 298 G4int ip3 = (G4int)p3;
>> 299 for (G4int i=0; i<ip3; i++) loss += 1./(1.-w*G4UniformRand());
>> 300 loss *= e0*corrfac;
>> 301 // smearing for losses near to e0
>> 302 if(p3 <= 2.)
>> 303 loss += e0*(1.-2.*G4UniformRand()) ;
>> 304 }
>> 305
>> 306 return loss;
239 } 307 }
240 308
241 //....oooOO0OOooo........oooOO0OOooo........oo 309 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
242 310
243 311
244 G4double G4UniversalFluctuation::Dispersion( 312 G4double G4UniversalFluctuation::Dispersion(
245 const G4Material* ma 313 const G4Material* material,
246 const G4DynamicParti 314 const G4DynamicParticle* dp,
247 const G4double tcut, << 315 G4double& tmax,
248 const G4double tmax, << 316 G4double& length)
249 const G4double lengt <<
250 { 317 {
251 if(dp->GetDefinition() != particle) { Initia << 318 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 } <<
256 319
257 //....oooOO0OOooo........oooOO0OOooo........oo << 320 electronDensity = material->GetElectronDensity();
258 321
259 void << 322 G4double gam = (dp->GetKineticEnergy())/particleMass + 1.0;
260 G4UniversalFluctuation::SetParticleAndCharge(c << 323 G4double beta2 = 1.0 - 1.0/(gam*gam);
261 G << 324
262 { << 325 G4double siga = (1.0/beta2 - 0.5) * twopi_mc2_rcl2 * tmax * length
263 if(part != particle) { << 326 * electronDensity * chargeSquare;
264 particle = part; << 327
265 particleMass = part->GetPDGMass(); << 328 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 } 329 }
273 330
274 //....oooOO0OOooo........oooOO0OOooo........oo 331 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
275 332