source: trunk/source/processes/electromagnetic/polarisation/src/G4eplusPolarizedAnnihilation.cc@ 1347

Last change on this file since 1347 was 1337, checked in by garnier, 15 years ago

tag geant4.9.4 beta 1 + modifs locales
File size: 14.7 KB
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[819]1//
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25//
[961]26// $Id: G4eplusPolarizedAnnihilation.cc,v 1.8 2008/10/30 22:34:23 schaelic Exp $
[1337]27// GEANT4 tag $Name: geant4-09-04-beta-01 $
[819]28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name: G4eplusPolarizedAnnihilation
35//
36// Author: A. Schaelicke on base of Vladimir Ivanchenko / Michel Maire code
37//
38// Creation date: 02.07.2006
39//
40// Modifications:
41// 26-07-06 modified cross section (P. Starovoitov)
42// 21-08-06 interface updated (A. Schaelicke)
43// 11-06-07, add PostStepGetPhysicalInteractionLength (A.Schalicke)
44// 02-10-07, enable AtRest (V.Ivanchenko)
45//
46//
47// Class Description:
48//
49// Polarized process of e+ annihilation into 2 gammas
50//
51
52//
53// -------------------------------------------------------------------
54//
55//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
56//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
57
58#include "G4eplusPolarizedAnnihilation.hh"
59#include "G4MaterialCutsCouple.hh"
60#include "G4Gamma.hh"
61#include "G4PhysicsVector.hh"
62#include "G4PhysicsLogVector.hh"
63
64
65#include "G4PolarizedAnnihilationModel.hh"
66#include "G4PhysicsTableHelper.hh"
67#include "G4ProductionCutsTable.hh"
68#include "G4PolarizationManager.hh"
69#include "G4PolarizationHelper.hh"
70#include "G4StokesVector.hh"
71
72//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
73
74G4eplusPolarizedAnnihilation::G4eplusPolarizedAnnihilation(const G4String& name)
75 : G4VEmProcess(name), isInitialised(false),
76 theAsymmetryTable(NULL),
77 theTransverseAsymmetryTable(NULL)
78{
79 enableAtRestDoIt = true;
[961]80 SetProcessSubType(fAnnihilation);
[819]81}
82
83//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
84
85G4eplusPolarizedAnnihilation::~G4eplusPolarizedAnnihilation()
86{
87 if (theAsymmetryTable) {
88 theAsymmetryTable->clearAndDestroy();
89 delete theAsymmetryTable;
90 }
91 if (theTransverseAsymmetryTable) {
92 theTransverseAsymmetryTable->clearAndDestroy();
93 delete theTransverseAsymmetryTable;
94 }
95}
96
97//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
98
99void G4eplusPolarizedAnnihilation::InitialiseProcess(const G4ParticleDefinition*)
100{
101 if(!isInitialised) {
102 isInitialised = true;
103 // SetVerboseLevel(3);
104 SetBuildTableFlag(true);
105 SetStartFromNullFlag(false);
106 SetSecondaryParticle(G4Gamma::Gamma());
107 G4double emin = 0.1*keV;
108 G4double emax = 100.*TeV;
109 SetLambdaBinning(120);
110 SetMinKinEnergy(emin);
111 SetMaxKinEnergy(emax);
112 emModel = new G4PolarizedAnnihilationModel();
113 emModel->SetLowEnergyLimit(emin);
114 emModel->SetHighEnergyLimit(emax);
115 AddEmModel(1, emModel);
116 }
117}
118
119
120//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
121
122 // for polarization
123
124G4double G4eplusPolarizedAnnihilation::GetMeanFreePath(const G4Track& track,
125 G4double previousStepSize,
126 G4ForceCondition* condition)
127{
128 G4double mfp = G4VEmProcess::GetMeanFreePath(track, previousStepSize, condition);
129
130 if (theAsymmetryTable) {
131
132 G4Material* aMaterial = track.GetMaterial();
133 G4VPhysicalVolume* aPVolume = track.GetVolume();
134 G4LogicalVolume* aLVolume = aPVolume->GetLogicalVolume();
135
136 // G4Material* bMaterial = aLVolume->GetMaterial();
137 G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
138
139 const G4bool volumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
140 G4StokesVector electronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
141
142 if (!volumeIsPolarized || mfp == DBL_MAX) return mfp;
143
144 // *** get asymmetry, if target is polarized ***
145 const G4DynamicParticle* aDynamicPositron = track.GetDynamicParticle();
146 const G4double positronEnergy = aDynamicPositron->GetKineticEnergy();
147 const G4StokesVector positronPolarization = track.GetPolarization();
148 const G4ParticleMomentum positronDirection0 = aDynamicPositron->GetMomentumDirection();
149
150 if (verboseLevel>=2) {
151
152 G4cout << " Mom " << positronDirection0 << G4endl;
153 G4cout << " Polarization " << positronPolarization << G4endl;
154 G4cout << " MaterialPol. " << electronPolarization << G4endl;
155 G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
156 G4cout << " Log. Volume " << aLVolume->GetName() << G4endl;
157 G4cout << " Material " << aMaterial << G4endl;
158 }
159
160 G4bool isOutRange;
161 G4int idx= CurrentMaterialCutsCoupleIndex();
162 G4double lAsymmetry = (*theAsymmetryTable)(idx)->
163 GetValue(positronEnergy, isOutRange);
164 G4double tAsymmetry = (*theTransverseAsymmetryTable)(idx)->
165 GetValue(positronEnergy, isOutRange);
166
167 G4double polZZ = positronPolarization.z()*
168 electronPolarization*positronDirection0;
169 G4double polXX = positronPolarization.x()*
170 electronPolarization*G4PolarizationHelper::GetParticleFrameX(positronDirection0);
171 G4double polYY = positronPolarization.y()*
172 electronPolarization*G4PolarizationHelper::GetParticleFrameY(positronDirection0);
173
174 G4double impact = 1. + polZZ*lAsymmetry + (polXX + polYY)*tAsymmetry;
175
176 mfp *= 1. / impact;
177
178 if (verboseLevel>=2) {
179 G4cout << " MeanFreePath: " << mfp / mm << " mm " << G4endl;
180 G4cout << " Asymmetry: " << lAsymmetry << ", " << tAsymmetry << G4endl;
181 G4cout << " PolProduct: " << polXX << ", " << polYY << ", " << polZZ << G4endl;
182 }
183 }
184
185 return mfp;
186}
187
188//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
189
190G4double G4eplusPolarizedAnnihilation::PostStepGetPhysicalInteractionLength(
191 const G4Track& track,
192 G4double previousStepSize,
193 G4ForceCondition* condition)
194{
195 G4double mfp = G4VEmProcess::PostStepGetPhysicalInteractionLength(track, previousStepSize, condition);
196
197 if (theAsymmetryTable) {
198
199 G4Material* aMaterial = track.GetMaterial();
200 G4VPhysicalVolume* aPVolume = track.GetVolume();
201 G4LogicalVolume* aLVolume = aPVolume->GetLogicalVolume();
202
203 // G4Material* bMaterial = aLVolume->GetMaterial();
204 G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
205
206 const G4bool volumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
207 G4StokesVector electronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
208
209 if (!volumeIsPolarized || mfp == DBL_MAX) return mfp;
210
211 // *** get asymmetry, if target is polarized ***
212 const G4DynamicParticle* aDynamicPositron = track.GetDynamicParticle();
213 const G4double positronEnergy = aDynamicPositron->GetKineticEnergy();
214 const G4StokesVector positronPolarization = track.GetPolarization();
215 const G4ParticleMomentum positronDirection0 = aDynamicPositron->GetMomentumDirection();
216
217 if (verboseLevel>=2) {
218
219 G4cout << " Mom " << positronDirection0 << G4endl;
220 G4cout << " Polarization " << positronPolarization << G4endl;
221 G4cout << " MaterialPol. " << electronPolarization << G4endl;
222 G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
223 G4cout << " Log. Volume " << aLVolume->GetName() << G4endl;
224 G4cout << " Material " << aMaterial << G4endl;
225 }
226
227 G4bool isOutRange;
228 G4int idx= CurrentMaterialCutsCoupleIndex();
229 G4double lAsymmetry = (*theAsymmetryTable)(idx)->
230 GetValue(positronEnergy, isOutRange);
231 G4double tAsymmetry = (*theTransverseAsymmetryTable)(idx)->
232 GetValue(positronEnergy, isOutRange);
233
234 G4double polZZ = positronPolarization.z()*
235 electronPolarization*positronDirection0;
236 G4double polXX = positronPolarization.x()*
237 electronPolarization*G4PolarizationHelper::GetParticleFrameX(positronDirection0);
238 G4double polYY = positronPolarization.y()*
239 electronPolarization*G4PolarizationHelper::GetParticleFrameY(positronDirection0);
240
241 G4double impact = 1. + polZZ*lAsymmetry + (polXX + polYY)*tAsymmetry;
242
243 mfp *= 1. / impact;
244
245 if (verboseLevel>=2) {
246 G4cout << " MeanFreePath: " << mfp / mm << " mm " << G4endl;
247 G4cout << " Asymmetry: " << lAsymmetry << ", " << tAsymmetry << G4endl;
248 G4cout << " PolProduct: " << polXX << ", " << polYY << ", " << polZZ << G4endl;
249 }
250 }
251
252 return mfp;
253}
254//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
255
256void G4eplusPolarizedAnnihilation::BuildPhysicsTable(const G4ParticleDefinition& pd)
257{
258 G4VEmProcess::BuildPhysicsTable(pd);
259 BuildAsymmetryTable(pd);
260}
261//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
262
263void G4eplusPolarizedAnnihilation::PreparePhysicsTable(const G4ParticleDefinition& pd)
264{
265 G4VEmProcess::PreparePhysicsTable(pd);
266 theAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theAsymmetryTable);
267 theTransverseAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theTransverseAsymmetryTable);
268}
269
270void G4eplusPolarizedAnnihilation::BuildAsymmetryTable(const G4ParticleDefinition& part)
271{
272 // Access to materials
273 const G4ProductionCutsTable* theCoupleTable=
274 G4ProductionCutsTable::GetProductionCutsTable();
275 size_t numOfCouples = theCoupleTable->GetTableSize();
276 G4cout<<" annih-numOfCouples="<<numOfCouples<<"\n";
277 for(size_t i=0; i<numOfCouples; ++i) {
278 G4cout<<"annih- "<<i<<"/"<<numOfCouples<<"\n";
279 if (!theAsymmetryTable) break;
280 G4cout<<"annih- "<<theAsymmetryTable->GetFlag(i)<<"\n";
281 if (theAsymmetryTable->GetFlag(i)) {
282 G4cout<<" building pol-annih ... \n";
283
284 // create physics vector and fill it
285 const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple(i);
286
287 // use same parameters as for lambda
288 G4PhysicsVector* aVector = LambdaPhysicsVector(couple);
289 G4PhysicsVector* tVector = LambdaPhysicsVector(couple);
290
291 for (G4int j = 0 ; j < LambdaBinning() ; ++j ) {
292 G4double lowEdgeEnergy = aVector->GetLowEdgeEnergy(j);
293 G4double tasm=0.;
294 G4double asym = ComputeAsymmetry(lowEdgeEnergy, couple, part, 0., tasm);
295 aVector->PutValue(j,asym);
296 tVector->PutValue(j,tasm);
297 }
298
299 G4PhysicsTableHelper::SetPhysicsVector(theAsymmetryTable, i, aVector);
300 G4PhysicsTableHelper::SetPhysicsVector(theTransverseAsymmetryTable, i, tVector);
301 }
302 }
303
304}
305
306
307//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
308
309G4double G4eplusPolarizedAnnihilation::ComputeAsymmetry(G4double energy,
310 const G4MaterialCutsCouple* couple,
311 const G4ParticleDefinition& aParticle,
312 G4double cut,
313 G4double &tAsymmetry)
314{
315 G4double lAsymmetry = 0.0;
316 tAsymmetry = 0.0;
317
318 // calculate polarized cross section
319 theTargetPolarization=G4ThreeVector(0.,0.,1.);
320 emModel->SetTargetPolarization(theTargetPolarization);
321 emModel->SetBeamPolarization(theTargetPolarization);
322 G4double sigma2=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
323
324 // calculate transversely polarized cross section
325 theTargetPolarization=G4ThreeVector(1.,0.,0.);
326 emModel->SetTargetPolarization(theTargetPolarization);
327 emModel->SetBeamPolarization(theTargetPolarization);
328 G4double sigma3=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
329
330 // calculate unpolarized cross section
331 theTargetPolarization=G4ThreeVector();
332 emModel->SetTargetPolarization(theTargetPolarization);
333 emModel->SetBeamPolarization(theTargetPolarization);
334 G4double sigma0=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
335
336 // determine assymmetries
337 if (sigma0>0.) {
338 lAsymmetry=sigma2/sigma0-1.;
339 tAsymmetry=sigma3/sigma0-1.;
340 }
341 return lAsymmetry;
342
343}
344
345
346
347//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
348
349void G4eplusPolarizedAnnihilation::PrintInfo()
350{
351 G4cout << " Polarized model for annihilation into 2 photons"
352 << G4endl;
353}
354
355//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
356
357G4VParticleChange* G4eplusPolarizedAnnihilation::AtRestDoIt(const G4Track& aTrack,
358 const G4Step& )
359//
360// Performs the e+ e- annihilation when both particles are assumed at rest.
361// It generates two back to back photons with energy = electron_mass.
362// The angular distribution is isotropic.
363// GEANT4 internal units
364//
365// Note : Effects due to binding of atomic electrons are negliged.
366{
367 fParticleChange.InitializeForPostStep(aTrack);
368
369 fParticleChange.SetNumberOfSecondaries(2);
370
371 G4double cosTeta = 2.*G4UniformRand()-1. , sinTeta = std::sqrt(1.-cosTeta*cosTeta);
372 G4double phi = twopi * G4UniformRand();
373 G4ThreeVector direction (sinTeta*std::cos(phi), sinTeta*std::sin(phi), cosTeta);
374 fParticleChange.AddSecondary( new G4DynamicParticle (G4Gamma::Gamma(),
375 direction, electron_mass_c2) );
376 fParticleChange.AddSecondary( new G4DynamicParticle (G4Gamma::Gamma(),
377 -direction, electron_mass_c2) );
378 // Kill the incident positron
379 //
380 fParticleChange.ProposeTrackStatus(fStopAndKill);
381 return &fParticleChange;
382}
383
384//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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