1 | // |
---|
2 | // ******************************************************************** |
---|
3 | // * License and Disclaimer * |
---|
4 | // * * |
---|
5 | // * The Geant4 software is copyright of the Copyright Holders of * |
---|
6 | // * the Geant4 Collaboration. It is provided under the terms and * |
---|
7 | // * conditions of the Geant4 Software License, included in the file * |
---|
8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
---|
9 | // * include a list of copyright holders. * |
---|
10 | // * * |
---|
11 | // * Neither the authors of this software system, nor their employing * |
---|
12 | // * institutes,nor the agencies providing financial support for this * |
---|
13 | // * work make any representation or warranty, express or implied, * |
---|
14 | // * regarding this software system or assume any liability for its * |
---|
15 | // * use. Please see the license in the file LICENSE and URL above * |
---|
16 | // * for the full disclaimer and the limitation of liability. * |
---|
17 | // * * |
---|
18 | // * This code implementation is the result of the scientific and * |
---|
19 | // * technical work of the GEANT4 collaboration. * |
---|
20 | // * By using, copying, modifying or distributing the software (or * |
---|
21 | // * any work based on the software) you agree to acknowledge its * |
---|
22 | // * use in resulting scientific publications, and indicate your * |
---|
23 | // * acceptance of all terms of the Geant4 Software license. * |
---|
24 | // ******************************************************************** |
---|
25 | // |
---|
26 | // $Id: G4eeToHadronsModel.cc,v 1.9 2008/07/10 18:06:39 vnivanch Exp $ |
---|
27 | // GEANT4 tag $Name: geant4-09-03 $ |
---|
28 | // |
---|
29 | // ------------------------------------------------------------------- |
---|
30 | // |
---|
31 | // GEANT4 Class header file |
---|
32 | // |
---|
33 | // |
---|
34 | // File name: G4eeToHadronsModel |
---|
35 | // |
---|
36 | // Author: Vladimir Ivanchenko |
---|
37 | // |
---|
38 | // Creation date: 12.08.2003 |
---|
39 | // |
---|
40 | // Modifications: |
---|
41 | // 08-04-05 Major optimisation of internal interfaces (V.Ivantchenko) |
---|
42 | // 18-05-05 Use optimized interfaces (V.Ivantchenko) |
---|
43 | // |
---|
44 | // |
---|
45 | // ------------------------------------------------------------------- |
---|
46 | // |
---|
47 | |
---|
48 | |
---|
49 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
50 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
51 | |
---|
52 | #include "G4eeToHadronsModel.hh" |
---|
53 | #include "Randomize.hh" |
---|
54 | #include "G4Electron.hh" |
---|
55 | #include "G4Gamma.hh" |
---|
56 | #include "G4Positron.hh" |
---|
57 | #include "G4PionPlus.hh" |
---|
58 | #include "Randomize.hh" |
---|
59 | #include "G4Vee2hadrons.hh" |
---|
60 | #include "G4PhysicsVector.hh" |
---|
61 | #include "G4PhysicsLogVector.hh" |
---|
62 | |
---|
63 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
64 | |
---|
65 | using namespace std; |
---|
66 | |
---|
67 | G4eeToHadronsModel::G4eeToHadronsModel(G4Vee2hadrons* m, G4int ver, |
---|
68 | const G4String& nam) |
---|
69 | : G4VEmModel(nam), |
---|
70 | model(m), |
---|
71 | crossPerElectron(0), |
---|
72 | crossBornPerElectron(0), |
---|
73 | isInitialised(false), |
---|
74 | nbins(100), |
---|
75 | verbose(ver) |
---|
76 | { |
---|
77 | theGamma = G4Gamma::Gamma(); |
---|
78 | } |
---|
79 | |
---|
80 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
81 | |
---|
82 | G4eeToHadronsModel::~G4eeToHadronsModel() |
---|
83 | { |
---|
84 | delete model; |
---|
85 | delete crossPerElectron; |
---|
86 | delete crossBornPerElectron; |
---|
87 | } |
---|
88 | |
---|
89 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
90 | |
---|
91 | void G4eeToHadronsModel::Initialise(const G4ParticleDefinition*, |
---|
92 | const G4DataVector&) |
---|
93 | { |
---|
94 | if(isInitialised) return; |
---|
95 | isInitialised = true; |
---|
96 | |
---|
97 | // Lab system |
---|
98 | highKinEnergy = HighEnergyLimit(); |
---|
99 | lowKinEnergy = LowEnergyLimit(); |
---|
100 | |
---|
101 | // CM system |
---|
102 | emin = model->LowEnergy(); |
---|
103 | emax = model->HighEnergy(); |
---|
104 | |
---|
105 | G4double emin0 = |
---|
106 | 2.0*electron_mass_c2*sqrt(1.0 + 0.5*lowKinEnergy/electron_mass_c2); |
---|
107 | G4double emax0 = |
---|
108 | 2.0*electron_mass_c2*sqrt(1.0 + 0.5*highKinEnergy/electron_mass_c2); |
---|
109 | |
---|
110 | // recompute low energy |
---|
111 | if(emin0 > emax) { |
---|
112 | emin0 = emax; |
---|
113 | model->SetLowEnergy(emin0); |
---|
114 | } |
---|
115 | if(emin > emin0) { |
---|
116 | emin0 = emin; |
---|
117 | lowKinEnergy = 0.5*emin*emin/electron_mass_c2 - 2.0*electron_mass_c2; |
---|
118 | SetLowEnergyLimit(lowKinEnergy); |
---|
119 | } |
---|
120 | |
---|
121 | // recompute high energy |
---|
122 | if(emax < emax0) { |
---|
123 | emax0 = emax; |
---|
124 | highKinEnergy = 0.5*emax*emax/electron_mass_c2 - 2.0*electron_mass_c2; |
---|
125 | SetHighEnergyLimit(highKinEnergy); |
---|
126 | } |
---|
127 | |
---|
128 | // peak energy |
---|
129 | epeak = std::min(model->PeakEnergy(), emax); |
---|
130 | peakKinEnergy = 0.5*epeak*epeak/electron_mass_c2 - 2.0*electron_mass_c2; |
---|
131 | |
---|
132 | if(verbose>0) { |
---|
133 | G4cout << "G4eeToHadronsModel::Initialise: " << G4endl; |
---|
134 | G4cout << "LabSystem: emin(GeV)= " << lowKinEnergy/GeV |
---|
135 | << " epeak(GeV)= " << peakKinEnergy/GeV |
---|
136 | << " emax(GeV)= " << highKinEnergy/GeV |
---|
137 | << G4endl; |
---|
138 | G4cout << "SM System: emin(MeV)= " << emin/MeV |
---|
139 | << " epeak(MeV)= " << epeak/MeV |
---|
140 | << " emax(MeV)= " << emax/MeV |
---|
141 | << G4endl; |
---|
142 | } |
---|
143 | |
---|
144 | if(lowKinEnergy < peakKinEnergy) { |
---|
145 | crossBornPerElectron = model->PhysicsVector(emin, emax); |
---|
146 | crossPerElectron = model->PhysicsVector(emin, emax); |
---|
147 | nbins = crossPerElectron->GetVectorLength(); |
---|
148 | for(G4int i=0; i<nbins; i++) { |
---|
149 | G4double e = crossPerElectron->GetLowEdgeEnergy(i); |
---|
150 | G4double cs = model->ComputeCrossSection(e); |
---|
151 | crossBornPerElectron->PutValue(i, cs); |
---|
152 | } |
---|
153 | ComputeCMCrossSectionPerElectron(); |
---|
154 | } |
---|
155 | if(verbose>1) { |
---|
156 | G4cout << "G4eeToHadronsModel: Cross secsions per electron" |
---|
157 | << " nbins= " << nbins |
---|
158 | << " emin(MeV)= " << emin/MeV |
---|
159 | << " emax(MeV)= " << emax/MeV |
---|
160 | << G4endl; |
---|
161 | G4bool b; |
---|
162 | for(G4int i=0; i<nbins; i++) { |
---|
163 | G4double e = crossPerElectron->GetLowEdgeEnergy(i); |
---|
164 | G4double s1 = crossPerElectron->GetValue(e, b); |
---|
165 | G4double s2 = crossBornPerElectron->GetValue(e, b); |
---|
166 | G4cout << "E(MeV)= " << e/MeV |
---|
167 | << " cross(nb)= " << s1/nanobarn |
---|
168 | << " crossBorn(nb)= " << s2/nanobarn |
---|
169 | << G4endl; |
---|
170 | } |
---|
171 | } |
---|
172 | } |
---|
173 | |
---|
174 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
175 | |
---|
176 | G4double G4eeToHadronsModel::CrossSectionPerVolume( |
---|
177 | const G4Material* mat, |
---|
178 | const G4ParticleDefinition* p, |
---|
179 | G4double kineticEnergy, |
---|
180 | G4double, G4double) |
---|
181 | { |
---|
182 | return mat->GetElectronDensity()* |
---|
183 | ComputeCrossSectionPerElectron(p, kineticEnergy); |
---|
184 | } |
---|
185 | |
---|
186 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
187 | |
---|
188 | G4double G4eeToHadronsModel::ComputeCrossSectionPerAtom( |
---|
189 | const G4ParticleDefinition* p, |
---|
190 | G4double kineticEnergy, |
---|
191 | G4double Z, G4double, |
---|
192 | G4double, G4double) |
---|
193 | { |
---|
194 | return Z*ComputeCrossSectionPerElectron(p, kineticEnergy); |
---|
195 | } |
---|
196 | |
---|
197 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
198 | |
---|
199 | G4double G4eeToHadronsModel::ComputeCrossSectionPerElectron( |
---|
200 | const G4ParticleDefinition*, |
---|
201 | G4double kineticEnergy, |
---|
202 | G4double, G4double) |
---|
203 | { |
---|
204 | G4double cross = 0.0; |
---|
205 | if(crossPerElectron) { |
---|
206 | G4bool b; |
---|
207 | G4double e = 2.0*electron_mass_c2* |
---|
208 | sqrt(1.0 + 0.5*kineticEnergy/electron_mass_c2); |
---|
209 | cross = crossPerElectron->GetValue(e, b); |
---|
210 | } |
---|
211 | // G4cout << "e= " << kineticEnergy << " cross= " << cross << G4endl; |
---|
212 | return cross; |
---|
213 | } |
---|
214 | |
---|
215 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
216 | |
---|
217 | void G4eeToHadronsModel::SampleSecondaries(std::vector<G4DynamicParticle*>* newp, |
---|
218 | const G4MaterialCutsCouple*, |
---|
219 | const G4DynamicParticle* dParticle, |
---|
220 | G4double, |
---|
221 | G4double) |
---|
222 | { |
---|
223 | if(crossPerElectron) { |
---|
224 | G4double t = dParticle->GetKineticEnergy(); |
---|
225 | G4double e = 2.0*electron_mass_c2*sqrt(1.0 + 0.5*t/electron_mass_c2); |
---|
226 | G4LorentzVector inlv = dParticle->Get4Momentum(); |
---|
227 | G4ThreeVector inBoost = inlv.boostVector(); |
---|
228 | if(e > emin) { |
---|
229 | G4DynamicParticle* gamma = GenerateCMPhoton(e); |
---|
230 | G4LorentzVector gLv = gamma->Get4Momentum(); |
---|
231 | G4LorentzVector lv(0.0,0.0,0.0,e); |
---|
232 | lv -= gLv; |
---|
233 | G4double m = lv.m(); |
---|
234 | G4ThreeVector boost = lv.boostVector(); |
---|
235 | const G4ThreeVector dir = gamma->GetMomentumDirection(); |
---|
236 | model->SampleSecondaries(newp, m, dir); |
---|
237 | G4int np = newp->size(); |
---|
238 | for(G4int j=0; j<np; j++) { |
---|
239 | G4DynamicParticle* dp = (*newp)[j]; |
---|
240 | G4LorentzVector v = dp->Get4Momentum(); |
---|
241 | v.boost(boost); |
---|
242 | v.boost(inBoost); |
---|
243 | dp->Set4Momentum(v); |
---|
244 | } |
---|
245 | gLv.boost(inBoost); |
---|
246 | gamma->Set4Momentum(gLv); |
---|
247 | newp->push_back(gamma); |
---|
248 | } |
---|
249 | } |
---|
250 | } |
---|
251 | |
---|
252 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
253 | |
---|
254 | void G4eeToHadronsModel::ComputeCMCrossSectionPerElectron() |
---|
255 | { |
---|
256 | G4bool b; |
---|
257 | for(G4int i=0; i<nbins; i++) { |
---|
258 | G4double e = crossPerElectron->GetLowEdgeEnergy(i); |
---|
259 | G4double cs = 0.0; |
---|
260 | if(i > 0) { |
---|
261 | G4double L = 2.0*log(e/electron_mass_c2); |
---|
262 | G4double bt = 2.0*fine_structure_const*(L - 1.0)/pi; |
---|
263 | G4double btm1= bt - 1.0; |
---|
264 | G4double del = 1. + fine_structure_const*(1.5*L + pi*pi/3. -2.)/pi; |
---|
265 | G4double s1 = crossBornPerElectron->GetValue(e, b); |
---|
266 | G4double e1 = crossPerElectron->GetLowEdgeEnergy(i-1); |
---|
267 | G4double x1 = 1. - e1/e; |
---|
268 | cs += s1*(del*pow(x1,bt) - bt*(x1 - 0.25*x1*x1)); |
---|
269 | if(i > 1) { |
---|
270 | G4double e2 = e1; |
---|
271 | G4double x2 = x1; |
---|
272 | G4double s2 = crossBornPerElectron->GetValue(e2, b); |
---|
273 | G4double w2 = bt*(del*pow(x2,btm1) - 1.0 + 0.5*x2); |
---|
274 | |
---|
275 | for(G4int j=i-2; j>=0; j--) { |
---|
276 | e1 = crossPerElectron->GetLowEdgeEnergy(j); |
---|
277 | x1 = 1. - e1/e; |
---|
278 | G4double s1 = crossBornPerElectron->GetValue(e1, b); |
---|
279 | G4double w1 = bt*(del*pow(x1,btm1) - 1.0 + 0.5*x1); |
---|
280 | cs += 0.5*(x1 - x2)*(w2*s2 + w1*s1); |
---|
281 | e2 = e1; |
---|
282 | x2 = x1; |
---|
283 | s2 = s1; |
---|
284 | w2 = w1; |
---|
285 | } |
---|
286 | } |
---|
287 | } |
---|
288 | crossPerElectron->PutValue(i, cs); |
---|
289 | // G4cout << "e= " << e << " cs= " << cs << G4endl; |
---|
290 | } |
---|
291 | } |
---|
292 | |
---|
293 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
294 | |
---|
295 | G4DynamicParticle* G4eeToHadronsModel::GenerateCMPhoton(G4double e) |
---|
296 | { |
---|
297 | G4bool b; |
---|
298 | G4double x; |
---|
299 | G4DynamicParticle* gamma = 0; |
---|
300 | G4double L = 2.0*log(e/electron_mass_c2); |
---|
301 | G4double bt = 2.0*fine_structure_const*(L - 1.)/pi; |
---|
302 | G4double btm1= bt - 1.0; |
---|
303 | G4double del = 1. + fine_structure_const*(1.5*L + pi*pi/3. -2.)/pi; |
---|
304 | |
---|
305 | G4double s0 = crossBornPerElectron->GetValue(e, b); |
---|
306 | G4double de = (emax - emin)/(G4double)nbins; |
---|
307 | G4double x0 = min(de,e - emin)/e; |
---|
308 | G4double ds = crossBornPerElectron->GetValue(e, b) |
---|
309 | *(del*pow(x0,bt) - bt*(x0 - 0.25*x0*x0)); |
---|
310 | G4double e1 = e*(1. - x0); |
---|
311 | |
---|
312 | if(e1 < emax && s0*G4UniformRand()<ds) { |
---|
313 | x = x0*pow(G4UniformRand(),1./bt); |
---|
314 | } else { |
---|
315 | |
---|
316 | x = 1. - e1/e; |
---|
317 | G4double s1 = crossBornPerElectron->GetValue(e1, b); |
---|
318 | G4double w1 = bt*(del*pow(x,btm1) - 1.0 + 0.5*x); |
---|
319 | G4double grej = s1*w1; |
---|
320 | G4double f; |
---|
321 | // G4cout << "e= " << e/GeV << " epeak= " << epeak/GeV |
---|
322 | // << " s1= " << s1 << " w1= " << w1 |
---|
323 | // << " grej= " << grej << G4endl; |
---|
324 | // Above emax cross section is 0 |
---|
325 | if(e1 > emax) { |
---|
326 | x = 1. - emax/e; |
---|
327 | G4double s2 = crossBornPerElectron->GetValue(emax, b); |
---|
328 | G4double w2 = bt*(del*pow(x,btm1) - 1.0 + 0.5*x); |
---|
329 | grej = s2*w2; |
---|
330 | // G4cout << "emax= " << emax << " s2= " << s2 << " w2= " << w2 |
---|
331 | // << " grej= " << grej << G4endl; |
---|
332 | } |
---|
333 | |
---|
334 | if(e1 > epeak) { |
---|
335 | x = 1. - epeak/e; |
---|
336 | G4double s2 = crossBornPerElectron->GetValue(epeak, b); |
---|
337 | G4double w2 = bt*(del*pow(x,btm1) - 1.0 + 0.5*x); |
---|
338 | grej = max(grej,s2*w2); |
---|
339 | //G4cout << "epeak= " << epeak << " s2= " << s2 << " w2= " << w2 |
---|
340 | // << " grej= " << grej << G4endl; |
---|
341 | } |
---|
342 | G4double xmin = 1. - e1/e; |
---|
343 | if(e1 > emax) xmin = 1. - emax/e; |
---|
344 | G4double xmax = 1. - emin/e; |
---|
345 | do { |
---|
346 | x = xmin + G4UniformRand()*(xmax - xmin); |
---|
347 | G4double s2 = crossBornPerElectron->GetValue((1.0 - x)*e, b); |
---|
348 | G4double w2 = bt*(del*pow(x,btm1) - 1.0 + 0.5*x); |
---|
349 | //G4cout << "x= " << x << " xmin= " << xmin << " xmax= " << xmax |
---|
350 | // << " s2= " << s2 << " w2= " << w2 |
---|
351 | // << G4endl; |
---|
352 | f = s2*w2; |
---|
353 | if(f > grej) { |
---|
354 | G4cout << "G4DynamicParticle* G4eeToHadronsModel:WARNING " |
---|
355 | << f << " > " << grej << " majorant is`small!" |
---|
356 | << G4endl; |
---|
357 | } |
---|
358 | } while (f < grej*G4UniformRand()); |
---|
359 | } |
---|
360 | |
---|
361 | G4ThreeVector dir(0.0,0.0,1.0); |
---|
362 | gamma = new G4DynamicParticle(theGamma,dir,x*e); |
---|
363 | return gamma; |
---|
364 | } |
---|
365 | |
---|
366 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
367 | |
---|