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28 //
29 // GEANT4 Class header file
30 //
31 //
32 // File name: G4MuBetheBlochModel
33 //
34 // Author: Vladimir Ivanchenko on base
35 //
36 // Creation date: 09.08.2002
37 //
38 // Modifications:
39 //
40 // 04-12-02 Fix problem of G4DynamicParticle c
41 // 23-12-02 Change interface in order to move
42 // 27-01-03 Make models region aware (V.Ivanch
43 // 13-02-03 Add name (V.Ivanchenko)
44 // 10-02-04 Calculation of radiative correctio
45 // 08-04-05 Major optimisation of internal int
46 // 12-04-05 Add usage of G4EmCorrections (V.Iv
47 // 13-02-06 ComputeCrossSectionPerElectron, Co
48 //
49
50 //
51 // -------------------------------------------
52 //
53
54 //....oooOO0OOooo........oooOO0OOooo........oo
55 //....oooOO0OOooo........oooOO0OOooo........oo
56
57 #include "G4MuBetheBlochModel.hh"
58 #include "G4PhysicalConstants.hh"
59 #include "G4SystemOfUnits.hh"
60 #include "Randomize.hh"
61 #include "G4Electron.hh"
62 #include "G4LossTableManager.hh"
63 #include "G4EmCorrections.hh"
64 #include "G4ParticleChangeForLoss.hh"
65 #include "G4Log.hh"
66 #include "G4Exp.hh"
67 #include "G4DeltaAngle.hh"
68
69 G4double G4MuBetheBlochModel::xgi[]={ 0.0199,
70 0.7628,
71
72 G4double G4MuBetheBlochModel::wgi[]={ 0.0506,
73 0.1569,
74
75 //....oooOO0OOooo........oooOO0OOooo........oo
76
77 G4MuBetheBlochModel::G4MuBetheBlochModel(const
78 const
79 : G4VEmModel(nam),
80 limitRadCorrection(250.*CLHEP::MeV),
81 limitKinEnergy(100.*CLHEP::keV),
82 logLimitKinEnergy(G4Log(limitKinEnergy)),
83 twoln10(2.0*G4Log(10.0)),
84 alphaprime(CLHEP::fine_structure_const/CLH
85 {
86 theElectron = G4Electron::Electron();
87 corr = G4LossTableManager::Instance()->EmCor
88 if(nullptr != p) { SetParticle(p); }
89 }
90
91 //....oooOO0OOooo........oooOO0OOooo........oo
92
93 G4double G4MuBetheBlochModel::MinEnergyCut(con
94 con
95 {
96 return couple->GetMaterial()->GetIonisation(
97 }
98
99 //....oooOO0OOooo........oooOO0OOooo........oo
100
101 G4double G4MuBetheBlochModel::MaxSecondaryEner
102
103 {
104 G4double tau = kinEnergy/mass;
105 G4double tmax = 2.0*CLHEP::electron_mass_c2*
106 (1. + 2.0*(tau + 1.)*ratio +
107 return tmax;
108 }
109
110 //....oooOO0OOooo........oooOO0OOooo........oo
111
112 void G4MuBetheBlochModel::SetParticle(const G4
113 {
114 if(nullptr == particle) {
115 particle = p;
116 mass = particle->GetPDGMass();
117 massSquare = mass*mass;
118 ratio = CLHEP::electron_mass_c2/mass;
119 }
120 }
121
122 //....oooOO0OOooo........oooOO0OOooo........oo
123
124 void G4MuBetheBlochModel::Initialise(const G4P
125 const G4D
126 {
127 SetParticle(p);
128 if(nullptr == fParticleChange) {
129 fParticleChange = GetParticleChangeForLoss
130 if(UseAngularGeneratorFlag() && nullptr ==
131 SetAngularDistribution(new G4DeltaAngle(
132 }
133 }
134 }
135
136 //....oooOO0OOooo........oooOO0OOooo........oo
137
138 G4double G4MuBetheBlochModel::ComputeCrossSect
139 con
140
141
142
143 {
144 G4double cross = 0.0;
145 G4double tmax = MaxSecondaryEnergy(p, kineti
146 G4double maxEnergy = std::min(tmax, maxKinEn
147 if(cutEnergy < maxEnergy) {
148
149 G4double totEnergy = kineticEnergy + mass;
150 G4double energy2 = totEnergy*totEnergy;
151 G4double beta2 = kineticEnergy*(kineticEne
152
153 cross = 1.0/cutEnergy - 1.0/maxEnergy -
154 beta2*G4Log(maxEnergy/cutEnergy)/tmax +
155 0.5*(maxEnergy - cutEnergy)/energy2;
156
157 // radiative corrections of R. Kokoulin
158 if (maxEnergy > limitKinEnergy && kineticE
159
160 G4double logtmax = G4Log(maxEnergy);
161 G4double logtmin = G4Log(std::max(cutEne
162 G4double logstep = logtmax - logtmin;
163 G4double dcross = 0.0;
164
165 for (G4int ll=0; ll<8; ++ll) {
166 G4double ep = G4Exp(logtmin + xgi[ll]*
167 G4double a1 = G4Log(1.0 + 2.0*ep/CLHEP
168 G4double a3 = G4Log(4.0*totEnergy*(tot
169 dcross += wgi[ll]*(1.0/ep - beta2/tmax
170 }
171 cross += dcross*logstep*alphaprime;
172 }
173 cross *= CLHEP::twopi_mc2_rcl2/beta2;
174 }
175 // G4cout << "tmin= " << cutEnergy << " tma
176 // << " cross= " << cross << G4endl;
177 return cross;
178 }
179
180 //....oooOO0OOooo........oooOO0OOooo........oo
181
182 G4double G4MuBetheBlochModel::ComputeCrossSect
183 con
184
185
186
187
188 {
189 G4double cross = Z*ComputeCrossSectionPerEle
190 (p,ki
191 return cross;
192 }
193
194 //....oooOO0OOooo........oooOO0OOooo........oo
195
196 G4double G4MuBetheBlochModel::CrossSectionPerV
197 con
198 con
199
200
201
202 {
203 G4double eDensity = material->GetElectronDen
204 G4double cross = eDensity*ComputeCrossSectio
205 (p,ki
206 return cross;
207 }
208
209 //....oooOO0OOooo........oooOO0OOooo........oo
210
211 G4double G4MuBetheBlochModel::ComputeDEDXPerVo
212
213
214
215 {
216 G4double tmax = MaxSecondaryEnergy(p, kinet
217 G4double tau = kineticEnergy/mass;
218 G4double cutEnergy = std::min(cut, tmax);
219 G4double gam = tau + 1.0;
220 G4double bg2 = tau * (tau+2.0);
221 G4double beta2 = bg2/(gam*gam);
222
223 G4double eexc = material->GetIonisation()->
224 G4double eexc2 = eexc*eexc;
225
226 G4double eDensity = material->GetElectronDen
227
228 G4double dedx = G4Log(2.0*CLHEP::electron_ma
229 -(1.0 + cutEnergy/tmax)*beta2
230
231 G4double totEnergy = kineticEnergy + mass;
232 G4double del = 0.5*cutEnergy/totEnergy;
233 dedx += del*del;
234
235 // density correction
236 G4double x = G4Log(bg2)/twoln10;
237 dedx -= material->GetIonisation()->DensityCo
238
239 // shell and high order corrections
240 dedx -= 2.0*corr->ShellCorrection(p,material
241
242 // radiative corrections of R. Kokoulin
243 if (cutEnergy > limitKinEnergy && kineticEne
244
245 G4double logtmax = G4Log(cutEnergy);
246 G4double logstep = logtmax - logLimitKinEn
247 G4double dloss = 0.0;
248 G4double ftot2= 0.5/(totEnergy*totEnergy);
249
250 for (G4int ll=0; ll<8; ++ll) {
251 G4double ep = G4Exp(logLimitKinEnergy +
252 G4double a1 = G4Log(1.0 + 2.0*ep/CLHEP::
253 G4double a3 = G4Log(4.0*totEnergy*(totEn
254 dloss += wgi[ll]*(1.0 - beta2*ep/tmax +
255 }
256 dedx += dloss*logstep*alphaprime;
257 }
258 dedx *= CLHEP::twopi_mc2_rcl2*eDensity/beta2
259
260 //High order corrections
261 dedx += corr->HighOrderCorrections(p,materia
262 dedx = std::max(dedx, 0.);
263 return dedx;
264 }
265
266 //....oooOO0OOooo........oooOO0OOooo........oo
267
268 void G4MuBetheBlochModel::SampleSecondaries(
269 std::vector<G4Dynami
270 const G4MaterialCutsCouple* couple,
271 const G4DynamicParticle* dp,
272 G4double minKinEnergy,
273 G4double maxEnergy)
274 {
275 G4double kineticEnergy = dp->GetKineticEnerg
276 G4double tmax = MaxSecondaryEnergy(dp->GetDe
277 G4double maxKinEnergy = std::min(maxEnergy,
278 if(minKinEnergy >= maxKinEnergy) { return; }
279
280 G4double totEnergy = kineticEnergy + mass;
281 G4double etot2 = totEnergy*totEnergy;
282 G4double beta2 = kineticEnergy*(kineticEnerg
283
284 G4double grej = 1.;
285 G4bool radC = (tmax > limitKinEnergy && kine
286 if(radC) {
287 G4double a0 = G4Log(2.*totEnergy/mass);
288 grej += alphaprime*a0*a0;
289 }
290
291 G4double tkin, f;
292
293 // sampling follows ...
294 do {
295 G4double q = G4UniformRand();
296 tkin = minKinEnergy*maxKinEnergy/(minKinEn
297 f = 1.0 - beta2*tkin/tmax + 0.5*tkin*tkin/
298
299 if(radC && tkin > limitKinEnergy) {
300 G4double a1 = G4Log(1.0 + 2.0*tkin/CLHEP
301 G4double a3 = G4Log(4.0*totEnergy*(totEn
302 f *= (1. + alphaprime*a1*(a3 - a1));
303 }
304
305 if(f > grej) {
306 G4cout << "G4MuBetheBlochModel::Sample
307 << "Majorant " << grej << " < "
308 << f << " for edelta= " << tkin
309 << " tmin= " << minKinEnergy <<
310 << G4endl;
311 }
312 // Loop checking, 03-Aug-2015, Vladimir Iv
313 } while( grej*G4UniformRand() > f );
314
315 G4ThreeVector deltaDirection;
316
317 if(UseAngularGeneratorFlag()) {
318 const G4Material* mat = couple->GetMateria
319 deltaDirection = GetAngularDistribution()-
320 SelectRandomAtomNumber(ma
321 } else {
322
323 G4double deltaMom = std::sqrt(tkin * (tkin
324 G4double totalMom = totEnergy*std::sqrt(be
325 G4double cost = tkin * (totEnergy + CLHEP:
326 (deltaMom * totalMom);
327 cost = std::min(cost, 1.0);
328 const G4double sint = std::sqrt((1.0 - cos
329 const G4double phi = twopi*G4UniformRand()
330
331 deltaDirection.set(sint*std::cos(phi),sint
332 deltaDirection.rotateUz(dp->GetMomentumDir
333 }
334 // create G4DynamicParticle object for delta
335 auto delta = new G4DynamicParticle(theElectr
336 vdp->push_back(delta);
337
338 // primary change
339 kineticEnergy -= tkin;
340 G4ThreeVector dir = dp->GetMomentum() - delt
341 dir = dir.unit();
342 fParticleChange->SetProposedKineticEnergy(ki
343 fParticleChange->SetProposedMomentumDirectio
344 }
345
346 //....oooOO0OOooo........oooOO0OOooo........oo
347