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: G4LivermorePolarizedComptonModel.cc,v 1.1 2008/10/30 14:16:35 sincerti Exp $ |
---|
27 | // GEANT4 tag $Name: geant4-09-02 $ |
---|
28 | // |
---|
29 | |
---|
30 | #include "G4LivermorePolarizedComptonModel.hh" |
---|
31 | |
---|
32 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
33 | |
---|
34 | using namespace std; |
---|
35 | |
---|
36 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
37 | |
---|
38 | G4LivermorePolarizedComptonModel::G4LivermorePolarizedComptonModel(const G4ParticleDefinition*, |
---|
39 | const G4String& nam) |
---|
40 | :G4VEmModel(nam),isInitialised(false) |
---|
41 | { |
---|
42 | lowEnergyLimit = 250 * eV; // SI - Could be 10 eV ? |
---|
43 | highEnergyLimit = 100 * GeV; |
---|
44 | SetLowEnergyLimit(lowEnergyLimit); |
---|
45 | SetHighEnergyLimit(highEnergyLimit); |
---|
46 | |
---|
47 | verboseLevel= 0; |
---|
48 | // Verbosity scale: |
---|
49 | // 0 = nothing |
---|
50 | // 1 = warning for energy non-conservation |
---|
51 | // 2 = details of energy budget |
---|
52 | // 3 = calculation of cross sections, file openings, sampling of atoms |
---|
53 | // 4 = entering in methods |
---|
54 | |
---|
55 | G4cout << "Livermore Polarized Compton is constructed " << G4endl |
---|
56 | << "Energy range: " |
---|
57 | << lowEnergyLimit / keV << " keV - " |
---|
58 | << highEnergyLimit / GeV << " GeV" |
---|
59 | << G4endl; |
---|
60 | |
---|
61 | } |
---|
62 | |
---|
63 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
64 | |
---|
65 | G4LivermorePolarizedComptonModel::~G4LivermorePolarizedComptonModel() |
---|
66 | { |
---|
67 | delete meanFreePathTable; |
---|
68 | delete crossSectionHandler; |
---|
69 | delete scatterFunctionData; |
---|
70 | } |
---|
71 | |
---|
72 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
73 | |
---|
74 | void G4LivermorePolarizedComptonModel::Initialise(const G4ParticleDefinition* particle, |
---|
75 | const G4DataVector& cuts) |
---|
76 | { |
---|
77 | if (verboseLevel > 3) |
---|
78 | G4cout << "Calling G4LivermorePolarizedComptonModel::Initialise()" << G4endl; |
---|
79 | |
---|
80 | InitialiseElementSelectors(particle,cuts); |
---|
81 | |
---|
82 | // Energy limits |
---|
83 | |
---|
84 | if (LowEnergyLimit() < lowEnergyLimit) |
---|
85 | { |
---|
86 | G4cout << "G4LivermorePolarizedComptonModel: low energy limit increased from " << |
---|
87 | LowEnergyLimit()/eV << " eV to " << lowEnergyLimit << " eV" << G4endl; |
---|
88 | SetLowEnergyLimit(lowEnergyLimit); |
---|
89 | } |
---|
90 | |
---|
91 | if (HighEnergyLimit() > highEnergyLimit) |
---|
92 | { |
---|
93 | G4cout << "G4LivermorePolarizedComptonModel: high energy limit decreased from " << |
---|
94 | HighEnergyLimit()/GeV << " GeV to " << highEnergyLimit << " GeV" << G4endl; |
---|
95 | SetHighEnergyLimit(highEnergyLimit); |
---|
96 | } |
---|
97 | |
---|
98 | // Reading of data files - all materials are read |
---|
99 | |
---|
100 | crossSectionHandler = new G4CrossSectionHandler; |
---|
101 | crossSectionHandler->Clear(); |
---|
102 | G4String crossSectionFile = "comp/ce-cs-"; |
---|
103 | crossSectionHandler->LoadData(crossSectionFile); |
---|
104 | |
---|
105 | meanFreePathTable = 0; |
---|
106 | meanFreePathTable = crossSectionHandler->BuildMeanFreePathForMaterials(); |
---|
107 | |
---|
108 | G4VDataSetAlgorithm* scatterInterpolation = new G4LogLogInterpolation; |
---|
109 | G4String scatterFile = "comp/ce-sf-"; |
---|
110 | scatterFunctionData = new G4CompositeEMDataSet(scatterInterpolation, 1., 1.); |
---|
111 | scatterFunctionData->LoadData(scatterFile); |
---|
112 | |
---|
113 | // For Doppler broadening |
---|
114 | shellData.SetOccupancyData(); |
---|
115 | G4String file = "/doppler/shell-doppler"; |
---|
116 | shellData.LoadData(file); |
---|
117 | |
---|
118 | // |
---|
119 | if (verboseLevel > 2) |
---|
120 | G4cout << "Loaded cross section files for Livermore Polarized Compton model" << G4endl; |
---|
121 | |
---|
122 | G4cout << "Livermore Polarized Compton model is initialized " << G4endl |
---|
123 | << "Energy range: " |
---|
124 | << LowEnergyLimit() / keV << " keV - " |
---|
125 | << HighEnergyLimit() / GeV << " GeV" |
---|
126 | << G4endl; |
---|
127 | |
---|
128 | // |
---|
129 | |
---|
130 | if(isInitialised) return; |
---|
131 | |
---|
132 | if(pParticleChange) |
---|
133 | fParticleChange = reinterpret_cast<G4ParticleChangeForGamma*>(pParticleChange); |
---|
134 | else |
---|
135 | fParticleChange = new G4ParticleChangeForGamma(); |
---|
136 | |
---|
137 | isInitialised = true; |
---|
138 | } |
---|
139 | |
---|
140 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
141 | |
---|
142 | G4double G4LivermorePolarizedComptonModel::ComputeCrossSectionPerAtom( |
---|
143 | const G4ParticleDefinition*, |
---|
144 | G4double GammaEnergy, |
---|
145 | G4double Z, G4double, |
---|
146 | G4double, G4double) |
---|
147 | { |
---|
148 | if (verboseLevel > 3) |
---|
149 | G4cout << "Calling ComputeCrossSectionPerAtom() of G4LivermorePolarizedComptonModel" << G4endl; |
---|
150 | |
---|
151 | G4double cs = crossSectionHandler->FindValue(G4int(Z), GammaEnergy); |
---|
152 | return cs; |
---|
153 | } |
---|
154 | |
---|
155 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
156 | |
---|
157 | void G4LivermorePolarizedComptonModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect, |
---|
158 | const G4MaterialCutsCouple* couple, |
---|
159 | const G4DynamicParticle* aDynamicGamma, |
---|
160 | G4double, |
---|
161 | G4double) |
---|
162 | { |
---|
163 | // The scattered gamma energy is sampled according to Klein - Nishina formula. |
---|
164 | // The random number techniques of Butcher & Messel are used (Nuc Phys 20(1960),15). |
---|
165 | // GEANT4 internal units |
---|
166 | // |
---|
167 | // Note : Effects due to binding of atomic electrons are negliged. |
---|
168 | |
---|
169 | if (verboseLevel > 3) |
---|
170 | G4cout << "Calling SampleSecondaries() of G4LivermorePolarizedComptonModel" << G4endl; |
---|
171 | |
---|
172 | G4double gammaEnergy0 = aDynamicGamma->GetKineticEnergy(); |
---|
173 | G4ThreeVector gammaPolarization0 = aDynamicGamma->GetPolarization(); |
---|
174 | |
---|
175 | // Protection: a polarisation parallel to the |
---|
176 | // direction causes problems; |
---|
177 | // in that case find a random polarization |
---|
178 | |
---|
179 | G4ThreeVector gammaDirection0 = aDynamicGamma->GetMomentumDirection(); |
---|
180 | |
---|
181 | // Make sure that the polarization vector is perpendicular to the |
---|
182 | // gamma direction. If not |
---|
183 | |
---|
184 | if(!(gammaPolarization0.isOrthogonal(gammaDirection0, 1e-6))||(gammaPolarization0.mag()==0)) |
---|
185 | { // only for testing now |
---|
186 | gammaPolarization0 = GetRandomPolarization(gammaDirection0); |
---|
187 | } |
---|
188 | else |
---|
189 | { |
---|
190 | if ( gammaPolarization0.howOrthogonal(gammaDirection0) != 0) |
---|
191 | { |
---|
192 | gammaPolarization0 = GetPerpendicularPolarization(gammaDirection0, gammaPolarization0); |
---|
193 | } |
---|
194 | } |
---|
195 | |
---|
196 | // End of Protection |
---|
197 | |
---|
198 | // Within energy limit? |
---|
199 | |
---|
200 | if(gammaEnergy0 <= lowEnergyLimit) |
---|
201 | { |
---|
202 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
---|
203 | fParticleChange->SetProposedKineticEnergy(0.); |
---|
204 | fParticleChange->ProposeLocalEnergyDeposit(gammaEnergy0); |
---|
205 | // SI - IS THE FOLLOWING RETURN NECESSARY ? |
---|
206 | return; |
---|
207 | } |
---|
208 | |
---|
209 | G4double E0_m = gammaEnergy0 / electron_mass_c2 ; |
---|
210 | |
---|
211 | // Select randomly one element in the current material |
---|
212 | |
---|
213 | G4int Z = crossSectionHandler->SelectRandomAtom(couple,gammaEnergy0); |
---|
214 | |
---|
215 | // Sample the energy and the polarization of the scattered photon |
---|
216 | |
---|
217 | G4double epsilon, epsilonSq, onecost, sinThetaSqr, greject ; |
---|
218 | |
---|
219 | G4double epsilon0 = 1./(1. + 2*E0_m); |
---|
220 | G4double epsilon0Sq = epsilon0*epsilon0; |
---|
221 | G4double alpha1 = - std::log(epsilon0); |
---|
222 | G4double alpha2 = 0.5*(1.- epsilon0Sq); |
---|
223 | |
---|
224 | G4double wlGamma = h_Planck*c_light/gammaEnergy0; |
---|
225 | G4double gammaEnergy1; |
---|
226 | G4ThreeVector gammaDirection1; |
---|
227 | |
---|
228 | do { |
---|
229 | if ( alpha1/(alpha1+alpha2) > G4UniformRand() ) |
---|
230 | { |
---|
231 | epsilon = std::exp(-alpha1*G4UniformRand()); |
---|
232 | epsilonSq = epsilon*epsilon; |
---|
233 | } |
---|
234 | else |
---|
235 | { |
---|
236 | epsilonSq = epsilon0Sq + (1.- epsilon0Sq)*G4UniformRand(); |
---|
237 | epsilon = std::sqrt(epsilonSq); |
---|
238 | } |
---|
239 | |
---|
240 | onecost = (1.- epsilon)/(epsilon*E0_m); |
---|
241 | sinThetaSqr = onecost*(2.-onecost); |
---|
242 | |
---|
243 | // Protection |
---|
244 | if (sinThetaSqr > 1.) |
---|
245 | { |
---|
246 | G4cout |
---|
247 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries " |
---|
248 | << "sin(theta)**2 = " |
---|
249 | << sinThetaSqr |
---|
250 | << "; set to 1" |
---|
251 | << G4endl; |
---|
252 | sinThetaSqr = 1.; |
---|
253 | } |
---|
254 | if (sinThetaSqr < 0.) |
---|
255 | { |
---|
256 | G4cout |
---|
257 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries " |
---|
258 | << "sin(theta)**2 = " |
---|
259 | << sinThetaSqr |
---|
260 | << "; set to 0" |
---|
261 | << G4endl; |
---|
262 | sinThetaSqr = 0.; |
---|
263 | } |
---|
264 | // End protection |
---|
265 | |
---|
266 | G4double x = std::sqrt(onecost/2.) / (wlGamma/cm);; |
---|
267 | G4double scatteringFunction = scatterFunctionData->FindValue(x,Z-1); |
---|
268 | greject = (1. - epsilon*sinThetaSqr/(1.+ epsilonSq))*scatteringFunction; |
---|
269 | |
---|
270 | } while(greject < G4UniformRand()*Z); |
---|
271 | |
---|
272 | |
---|
273 | // **************************************************** |
---|
274 | // Phi determination |
---|
275 | // **************************************************** |
---|
276 | |
---|
277 | G4double phi = SetPhi(epsilon,sinThetaSqr); |
---|
278 | |
---|
279 | // |
---|
280 | // scattered gamma angles. ( Z - axis along the parent gamma) |
---|
281 | // |
---|
282 | |
---|
283 | G4double cosTheta = 1. - onecost; |
---|
284 | |
---|
285 | // Protection |
---|
286 | |
---|
287 | if (cosTheta > 1.) |
---|
288 | { |
---|
289 | G4cout |
---|
290 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries " |
---|
291 | << "cosTheta = " |
---|
292 | << cosTheta |
---|
293 | << "; set to 1" |
---|
294 | << G4endl; |
---|
295 | cosTheta = 1.; |
---|
296 | } |
---|
297 | if (cosTheta < -1.) |
---|
298 | { |
---|
299 | G4cout |
---|
300 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries " |
---|
301 | << "cosTheta = " |
---|
302 | << cosTheta |
---|
303 | << "; set to -1" |
---|
304 | << G4endl; |
---|
305 | cosTheta = -1.; |
---|
306 | } |
---|
307 | // End protection |
---|
308 | |
---|
309 | |
---|
310 | G4double sinTheta = std::sqrt (sinThetaSqr); |
---|
311 | |
---|
312 | // Protection |
---|
313 | if (sinTheta > 1.) |
---|
314 | { |
---|
315 | G4cout |
---|
316 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries " |
---|
317 | << "sinTheta = " |
---|
318 | << sinTheta |
---|
319 | << "; set to 1" |
---|
320 | << G4endl; |
---|
321 | sinTheta = 1.; |
---|
322 | } |
---|
323 | if (sinTheta < -1.) |
---|
324 | { |
---|
325 | G4cout |
---|
326 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries " |
---|
327 | << "sinTheta = " |
---|
328 | << sinTheta |
---|
329 | << "; set to -1" |
---|
330 | << G4endl; |
---|
331 | sinTheta = -1.; |
---|
332 | } |
---|
333 | // End protection |
---|
334 | |
---|
335 | |
---|
336 | G4double dirx = sinTheta*std::cos(phi); |
---|
337 | G4double diry = sinTheta*std::sin(phi); |
---|
338 | G4double dirz = cosTheta ; |
---|
339 | |
---|
340 | |
---|
341 | // oneCosT , eom |
---|
342 | |
---|
343 | // Doppler broadening - Method based on: |
---|
344 | // Y. Namito, S. Ban and H. Hirayama, |
---|
345 | // "Implementation of the Doppler Broadening of a Compton-Scattered Photon Into the EGS4 Code" |
---|
346 | // NIM A 349, pp. 489-494, 1994 |
---|
347 | |
---|
348 | // Maximum number of sampling iterations |
---|
349 | |
---|
350 | G4int maxDopplerIterations = 1000; |
---|
351 | G4double bindingE = 0.; |
---|
352 | G4double photonEoriginal = epsilon * gammaEnergy0; |
---|
353 | G4double photonE = -1.; |
---|
354 | G4int iteration = 0; |
---|
355 | G4double eMax = gammaEnergy0; |
---|
356 | |
---|
357 | do |
---|
358 | { |
---|
359 | iteration++; |
---|
360 | // Select shell based on shell occupancy |
---|
361 | G4int shell = shellData.SelectRandomShell(Z); |
---|
362 | bindingE = shellData.BindingEnergy(Z,shell); |
---|
363 | |
---|
364 | eMax = gammaEnergy0 - bindingE; |
---|
365 | |
---|
366 | // Randomly sample bound electron momentum (memento: the data set is in Atomic Units) |
---|
367 | G4double pSample = profileData.RandomSelectMomentum(Z,shell); |
---|
368 | // Rescale from atomic units |
---|
369 | G4double pDoppler = pSample * fine_structure_const; |
---|
370 | G4double pDoppler2 = pDoppler * pDoppler; |
---|
371 | G4double var2 = 1. + onecost * E0_m; |
---|
372 | G4double var3 = var2*var2 - pDoppler2; |
---|
373 | G4double var4 = var2 - pDoppler2 * cosTheta; |
---|
374 | G4double var = var4*var4 - var3 + pDoppler2 * var3; |
---|
375 | if (var > 0.) |
---|
376 | { |
---|
377 | G4double varSqrt = std::sqrt(var); |
---|
378 | G4double scale = gammaEnergy0 / var3; |
---|
379 | // Random select either root |
---|
380 | if (G4UniformRand() < 0.5) photonE = (var4 - varSqrt) * scale; |
---|
381 | else photonE = (var4 + varSqrt) * scale; |
---|
382 | } |
---|
383 | else |
---|
384 | { |
---|
385 | photonE = -1.; |
---|
386 | } |
---|
387 | } while ( iteration <= maxDopplerIterations && |
---|
388 | (photonE < 0. || photonE > eMax || photonE < eMax*G4UniformRand()) ); |
---|
389 | |
---|
390 | // End of recalculation of photon energy with Doppler broadening |
---|
391 | // Revert to original if maximum number of iterations threshold has been reached |
---|
392 | if (iteration >= maxDopplerIterations) |
---|
393 | { |
---|
394 | photonE = photonEoriginal; |
---|
395 | bindingE = 0.; |
---|
396 | } |
---|
397 | |
---|
398 | gammaEnergy1 = photonE; |
---|
399 | |
---|
400 | // |
---|
401 | // update G4VParticleChange for the scattered photon |
---|
402 | // |
---|
403 | |
---|
404 | // gammaEnergy1 = epsilon*gammaEnergy0; |
---|
405 | |
---|
406 | |
---|
407 | // New polarization |
---|
408 | |
---|
409 | G4ThreeVector gammaPolarization1 = SetNewPolarization(epsilon, |
---|
410 | sinThetaSqr, |
---|
411 | phi, |
---|
412 | cosTheta); |
---|
413 | |
---|
414 | // Set new direction |
---|
415 | G4ThreeVector tmpDirection1( dirx,diry,dirz ); |
---|
416 | gammaDirection1 = tmpDirection1; |
---|
417 | |
---|
418 | // Change reference frame. |
---|
419 | |
---|
420 | SystemOfRefChange(gammaDirection0,gammaDirection1, |
---|
421 | gammaPolarization0,gammaPolarization1); |
---|
422 | |
---|
423 | if (gammaEnergy1 > 0.) |
---|
424 | { |
---|
425 | fParticleChange->SetProposedKineticEnergy( gammaEnergy1 ) ; |
---|
426 | fParticleChange->ProposeMomentumDirection( gammaDirection1 ); |
---|
427 | fParticleChange->ProposePolarization( gammaPolarization1 ); |
---|
428 | } |
---|
429 | else |
---|
430 | { |
---|
431 | fParticleChange->SetProposedKineticEnergy(0.) ; |
---|
432 | fParticleChange->ProposeTrackStatus(fStopAndKill); |
---|
433 | } |
---|
434 | |
---|
435 | // |
---|
436 | // kinematic of the scattered electron |
---|
437 | // |
---|
438 | |
---|
439 | G4double ElecKineEnergy = gammaEnergy0 - gammaEnergy1 -bindingE; |
---|
440 | |
---|
441 | // SI - Removed range test |
---|
442 | |
---|
443 | G4double ElecMomentum = std::sqrt(ElecKineEnergy*(ElecKineEnergy+2.*electron_mass_c2)); |
---|
444 | |
---|
445 | G4ThreeVector ElecDirection((gammaEnergy0 * gammaDirection0 - |
---|
446 | gammaEnergy1 * gammaDirection1) * (1./ElecMomentum)); |
---|
447 | |
---|
448 | fParticleChange->ProposeLocalEnergyDeposit(bindingE); |
---|
449 | |
---|
450 | G4DynamicParticle* dp = new G4DynamicParticle (G4Electron::Electron(),ElecDirection.unit(),ElecKineEnergy) ; |
---|
451 | fvect->push_back(dp); |
---|
452 | |
---|
453 | } |
---|
454 | |
---|
455 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
456 | |
---|
457 | G4double G4LivermorePolarizedComptonModel::SetPhi(G4double energyRate, |
---|
458 | G4double sinSqrTh) |
---|
459 | { |
---|
460 | G4double rand1; |
---|
461 | G4double rand2; |
---|
462 | G4double phiProbability; |
---|
463 | G4double phi; |
---|
464 | G4double a, b; |
---|
465 | |
---|
466 | do |
---|
467 | { |
---|
468 | rand1 = G4UniformRand(); |
---|
469 | rand2 = G4UniformRand(); |
---|
470 | phiProbability=0.; |
---|
471 | phi = twopi*rand1; |
---|
472 | |
---|
473 | a = 2*sinSqrTh; |
---|
474 | b = energyRate + 1/energyRate; |
---|
475 | |
---|
476 | phiProbability = 1 - (a/b)*(std::cos(phi)*std::cos(phi)); |
---|
477 | |
---|
478 | |
---|
479 | |
---|
480 | } |
---|
481 | while ( rand2 > phiProbability ); |
---|
482 | return phi; |
---|
483 | } |
---|
484 | |
---|
485 | |
---|
486 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
487 | |
---|
488 | G4ThreeVector G4LivermorePolarizedComptonModel::SetPerpendicularVector(G4ThreeVector& a) |
---|
489 | { |
---|
490 | G4double dx = a.x(); |
---|
491 | G4double dy = a.y(); |
---|
492 | G4double dz = a.z(); |
---|
493 | G4double x = dx < 0.0 ? -dx : dx; |
---|
494 | G4double y = dy < 0.0 ? -dy : dy; |
---|
495 | G4double z = dz < 0.0 ? -dz : dz; |
---|
496 | if (x < y) { |
---|
497 | return x < z ? G4ThreeVector(-dy,dx,0) : G4ThreeVector(0,-dz,dy); |
---|
498 | }else{ |
---|
499 | return y < z ? G4ThreeVector(dz,0,-dx) : G4ThreeVector(-dy,dx,0); |
---|
500 | } |
---|
501 | } |
---|
502 | |
---|
503 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
504 | |
---|
505 | G4ThreeVector G4LivermorePolarizedComptonModel::GetRandomPolarization(G4ThreeVector& direction0) |
---|
506 | { |
---|
507 | G4ThreeVector d0 = direction0.unit(); |
---|
508 | G4ThreeVector a1 = SetPerpendicularVector(d0); //different orthogonal |
---|
509 | G4ThreeVector a0 = a1.unit(); // unit vector |
---|
510 | |
---|
511 | G4double rand1 = G4UniformRand(); |
---|
512 | |
---|
513 | G4double angle = twopi*rand1; // random polar angle |
---|
514 | G4ThreeVector b0 = d0.cross(a0); // cross product |
---|
515 | |
---|
516 | G4ThreeVector c; |
---|
517 | |
---|
518 | c.setX(std::cos(angle)*(a0.x())+std::sin(angle)*b0.x()); |
---|
519 | c.setY(std::cos(angle)*(a0.y())+std::sin(angle)*b0.y()); |
---|
520 | c.setZ(std::cos(angle)*(a0.z())+std::sin(angle)*b0.z()); |
---|
521 | |
---|
522 | G4ThreeVector c0 = c.unit(); |
---|
523 | |
---|
524 | return c0; |
---|
525 | |
---|
526 | } |
---|
527 | |
---|
528 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
529 | |
---|
530 | G4ThreeVector G4LivermorePolarizedComptonModel::GetPerpendicularPolarization |
---|
531 | (const G4ThreeVector& gammaDirection, const G4ThreeVector& gammaPolarization) const |
---|
532 | { |
---|
533 | |
---|
534 | // |
---|
535 | // The polarization of a photon is always perpendicular to its momentum direction. |
---|
536 | // Therefore this function removes those vector component of gammaPolarization, which |
---|
537 | // points in direction of gammaDirection |
---|
538 | // |
---|
539 | // Mathematically we search the projection of the vector a on the plane E, where n is the |
---|
540 | // plains normal vector. |
---|
541 | // The basic equation can be found in each geometry book (e.g. Bronstein): |
---|
542 | // p = a - (a o n)/(n o n)*n |
---|
543 | |
---|
544 | return gammaPolarization - gammaPolarization.dot(gammaDirection)/gammaDirection.dot(gammaDirection) * gammaDirection; |
---|
545 | } |
---|
546 | |
---|
547 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
548 | |
---|
549 | G4ThreeVector G4LivermorePolarizedComptonModel::SetNewPolarization(G4double epsilon, |
---|
550 | G4double sinSqrTh, |
---|
551 | G4double phi, |
---|
552 | G4double costheta) |
---|
553 | { |
---|
554 | G4double rand1; |
---|
555 | G4double rand2; |
---|
556 | G4double cosPhi = std::cos(phi); |
---|
557 | G4double sinPhi = std::sin(phi); |
---|
558 | G4double sinTheta = std::sqrt(sinSqrTh); |
---|
559 | G4double cosSqrPhi = cosPhi*cosPhi; |
---|
560 | // G4double cossqrth = 1.-sinSqrTh; |
---|
561 | // G4double sinsqrphi = sinPhi*sinPhi; |
---|
562 | G4double normalisation = std::sqrt(1. - cosSqrPhi*sinSqrTh); |
---|
563 | |
---|
564 | |
---|
565 | // Determination of Theta |
---|
566 | |
---|
567 | // ---- MGP ---- Commented out the following 3 lines to avoid compilation |
---|
568 | // warnings (unused variables) |
---|
569 | // G4double thetaProbability; |
---|
570 | G4double theta; |
---|
571 | // G4double a, b; |
---|
572 | // G4double cosTheta; |
---|
573 | |
---|
574 | /* |
---|
575 | |
---|
576 | depaola method |
---|
577 | |
---|
578 | do |
---|
579 | { |
---|
580 | rand1 = G4UniformRand(); |
---|
581 | rand2 = G4UniformRand(); |
---|
582 | thetaProbability=0.; |
---|
583 | theta = twopi*rand1; |
---|
584 | a = 4*normalisation*normalisation; |
---|
585 | b = (epsilon + 1/epsilon) - 2; |
---|
586 | thetaProbability = (b + a*std::cos(theta)*std::cos(theta))/(a+b); |
---|
587 | cosTheta = std::cos(theta); |
---|
588 | } |
---|
589 | while ( rand2 > thetaProbability ); |
---|
590 | |
---|
591 | G4double cosBeta = cosTheta; |
---|
592 | |
---|
593 | */ |
---|
594 | |
---|
595 | |
---|
596 | // Dan Xu method (IEEE TNS, 52, 1160 (2005)) |
---|
597 | |
---|
598 | rand1 = G4UniformRand(); |
---|
599 | rand2 = G4UniformRand(); |
---|
600 | |
---|
601 | if (rand1<(epsilon+1.0/epsilon-2)/(2.0*(epsilon+1.0/epsilon)-4.0*sinSqrTh*cosSqrPhi)) |
---|
602 | { |
---|
603 | if (rand2<0.5) |
---|
604 | theta = pi/2.0; |
---|
605 | else |
---|
606 | theta = 3.0*pi/2.0; |
---|
607 | } |
---|
608 | else |
---|
609 | { |
---|
610 | if (rand2<0.5) |
---|
611 | theta = 0; |
---|
612 | else |
---|
613 | theta = pi; |
---|
614 | } |
---|
615 | G4double cosBeta = std::cos(theta); |
---|
616 | G4double sinBeta = std::sqrt(1-cosBeta*cosBeta); |
---|
617 | |
---|
618 | G4ThreeVector gammaPolarization1; |
---|
619 | |
---|
620 | G4double xParallel = normalisation*cosBeta; |
---|
621 | G4double yParallel = -(sinSqrTh*cosPhi*sinPhi)*cosBeta/normalisation; |
---|
622 | G4double zParallel = -(costheta*sinTheta*cosPhi)*cosBeta/normalisation; |
---|
623 | G4double xPerpendicular = 0.; |
---|
624 | G4double yPerpendicular = (costheta)*sinBeta/normalisation; |
---|
625 | G4double zPerpendicular = -(sinTheta*sinPhi)*sinBeta/normalisation; |
---|
626 | |
---|
627 | G4double xTotal = (xParallel + xPerpendicular); |
---|
628 | G4double yTotal = (yParallel + yPerpendicular); |
---|
629 | G4double zTotal = (zParallel + zPerpendicular); |
---|
630 | |
---|
631 | gammaPolarization1.setX(xTotal); |
---|
632 | gammaPolarization1.setY(yTotal); |
---|
633 | gammaPolarization1.setZ(zTotal); |
---|
634 | |
---|
635 | return gammaPolarization1; |
---|
636 | |
---|
637 | } |
---|
638 | |
---|
639 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
640 | |
---|
641 | void G4LivermorePolarizedComptonModel::SystemOfRefChange(G4ThreeVector& direction0, |
---|
642 | G4ThreeVector& direction1, |
---|
643 | G4ThreeVector& polarization0, |
---|
644 | G4ThreeVector& polarization1) |
---|
645 | { |
---|
646 | // direction0 is the original photon direction ---> z |
---|
647 | // polarization0 is the original photon polarization ---> x |
---|
648 | // need to specify y axis in the real reference frame ---> y |
---|
649 | G4ThreeVector Axis_Z0 = direction0.unit(); |
---|
650 | G4ThreeVector Axis_X0 = polarization0.unit(); |
---|
651 | G4ThreeVector Axis_Y0 = (Axis_Z0.cross(Axis_X0)).unit(); // to be confirmed; |
---|
652 | |
---|
653 | G4double direction_x = direction1.getX(); |
---|
654 | G4double direction_y = direction1.getY(); |
---|
655 | G4double direction_z = direction1.getZ(); |
---|
656 | |
---|
657 | direction1 = (direction_x*Axis_X0 + direction_y*Axis_Y0 + direction_z*Axis_Z0).unit(); |
---|
658 | G4double polarization_x = polarization1.getX(); |
---|
659 | G4double polarization_y = polarization1.getY(); |
---|
660 | G4double polarization_z = polarization1.getZ(); |
---|
661 | |
---|
662 | polarization1 = (polarization_x*Axis_X0 + polarization_y*Axis_Y0 + polarization_z*Axis_Z0).unit(); |
---|
663 | |
---|
664 | } |
---|
665 | |
---|
666 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
---|
667 | |
---|
668 | G4double G4LivermorePolarizedComptonModel::GetMeanFreePath(const G4Track& track, |
---|
669 | G4double, |
---|
670 | G4ForceCondition*) |
---|
671 | { |
---|
672 | const G4DynamicParticle* photon = track.GetDynamicParticle(); |
---|
673 | G4double energy = photon->GetKineticEnergy(); |
---|
674 | const G4MaterialCutsCouple* couple = track.GetMaterialCutsCouple(); |
---|
675 | size_t materialIndex = couple->GetIndex(); |
---|
676 | G4double meanFreePath; |
---|
677 | if (energy > highEnergyLimit) meanFreePath = meanFreePathTable->FindValue(highEnergyLimit,materialIndex); |
---|
678 | else if (energy < lowEnergyLimit) meanFreePath = DBL_MAX; |
---|
679 | else meanFreePath = meanFreePathTable->FindValue(energy,materialIndex); |
---|
680 | return meanFreePath; |
---|
681 | } |
---|
682 | |
---|
683 | |
---|