source: trunk/source/processes/electromagnetic/polarisation/src/G4eplusPolarizedAnnihilation.cc @ 846

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25//
26// $Id: G4eplusPolarizedAnnihilation.cc,v 1.6 2007/10/02 11:36:44 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-01-patch-02 $
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;
80}
81
82//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
83
84G4eplusPolarizedAnnihilation::~G4eplusPolarizedAnnihilation()
85{
86  if (theAsymmetryTable) {
87    theAsymmetryTable->clearAndDestroy();
88    delete theAsymmetryTable;
89  }
90  if (theTransverseAsymmetryTable) {
91    theTransverseAsymmetryTable->clearAndDestroy();
92    delete theTransverseAsymmetryTable;
93  }
94}
95
96//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
97
98void G4eplusPolarizedAnnihilation::InitialiseProcess(const G4ParticleDefinition*)
99{
100  if(!isInitialised) {
101    isInitialised = true;
102    //    SetVerboseLevel(3);
103    SetBuildTableFlag(true);
104    SetStartFromNullFlag(false);
105    SetSecondaryParticle(G4Gamma::Gamma());
106    G4double emin = 0.1*keV;
107    G4double emax = 100.*TeV;
108    SetLambdaBinning(120);
109    SetMinKinEnergy(emin);
110    SetMaxKinEnergy(emax);
111    emModel = new G4PolarizedAnnihilationModel();
112    emModel->SetLowEnergyLimit(emin);
113    emModel->SetHighEnergyLimit(emax);
114    AddEmModel(1, emModel);
115  }
116}
117
118
119//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
120
121  // for polarization
122
123G4double G4eplusPolarizedAnnihilation::GetMeanFreePath(const G4Track& track,
124                              G4double previousStepSize,
125                              G4ForceCondition* condition)
126{
127  G4double mfp = G4VEmProcess::GetMeanFreePath(track, previousStepSize, condition);
128
129  if (theAsymmetryTable) {
130
131    G4Material*         aMaterial = track.GetMaterial();
132    G4VPhysicalVolume*  aPVolume  = track.GetVolume();
133    G4LogicalVolume*    aLVolume  = aPVolume->GetLogicalVolume();
134   
135    //   G4Material* bMaterial = aLVolume->GetMaterial();
136    G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
137   
138    const G4bool volumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
139    G4StokesVector electronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
140
141    if (!volumeIsPolarized || mfp == DBL_MAX) return mfp;
142     
143    // *** get asymmetry, if target is polarized ***
144    const G4DynamicParticle* aDynamicPositron = track.GetDynamicParticle();
145    const G4double positronEnergy = aDynamicPositron->GetKineticEnergy();
146    const G4StokesVector positronPolarization = track.GetPolarization();
147    const G4ParticleMomentum positronDirection0 = aDynamicPositron->GetMomentumDirection();
148
149    if (verboseLevel>=2) {
150     
151      G4cout << " Mom " << positronDirection0  << G4endl;
152      G4cout << " Polarization " << positronPolarization  << G4endl;
153      G4cout << " MaterialPol. " << electronPolarization  << G4endl;
154      G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
155      G4cout << " Log. Volume  " << aLVolume->GetName() << G4endl;
156      G4cout << " Material     " << aMaterial          << G4endl;
157    }
158   
159    G4bool isOutRange;
160    G4int idx= CurrentMaterialCutsCoupleIndex();
161    G4double lAsymmetry = (*theAsymmetryTable)(idx)->
162                                  GetValue(positronEnergy, isOutRange);
163    G4double tAsymmetry = (*theTransverseAsymmetryTable)(idx)->
164                                  GetValue(positronEnergy, isOutRange);
165
166    G4double polZZ = positronPolarization.z()*
167      electronPolarization*positronDirection0;
168    G4double polXX = positronPolarization.x()*
169      electronPolarization*G4PolarizationHelper::GetParticleFrameX(positronDirection0);
170    G4double polYY = positronPolarization.y()*
171      electronPolarization*G4PolarizationHelper::GetParticleFrameY(positronDirection0);
172
173    G4double impact = 1. + polZZ*lAsymmetry + (polXX + polYY)*tAsymmetry;
174
175    mfp *= 1. / impact;
176
177    if (verboseLevel>=2) {
178      G4cout << " MeanFreePath:  " << mfp / mm << " mm " << G4endl;
179      G4cout << " Asymmetry:     " << lAsymmetry << ", " << tAsymmetry  << G4endl;
180      G4cout << " PolProduct:    " << polXX << ", " << polYY << ", " << polZZ << G4endl;
181    }
182  }
183 
184  return mfp;
185}
186
187//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
188
189G4double G4eplusPolarizedAnnihilation::PostStepGetPhysicalInteractionLength(
190                              const G4Track& track,
191                              G4double previousStepSize,
192                              G4ForceCondition* condition)
193{
194  G4double mfp = G4VEmProcess::PostStepGetPhysicalInteractionLength(track, previousStepSize, condition);
195
196  if (theAsymmetryTable) {
197
198    G4Material*         aMaterial = track.GetMaterial();
199    G4VPhysicalVolume*  aPVolume  = track.GetVolume();
200    G4LogicalVolume*    aLVolume  = aPVolume->GetLogicalVolume();
201   
202    //   G4Material* bMaterial = aLVolume->GetMaterial();
203    G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
204   
205    const G4bool volumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
206    G4StokesVector electronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
207
208    if (!volumeIsPolarized || mfp == DBL_MAX) return mfp;
209     
210    // *** get asymmetry, if target is polarized ***
211    const G4DynamicParticle* aDynamicPositron = track.GetDynamicParticle();
212    const G4double positronEnergy = aDynamicPositron->GetKineticEnergy();
213    const G4StokesVector positronPolarization = track.GetPolarization();
214    const G4ParticleMomentum positronDirection0 = aDynamicPositron->GetMomentumDirection();
215
216    if (verboseLevel>=2) {
217     
218      G4cout << " Mom " << positronDirection0  << G4endl;
219      G4cout << " Polarization " << positronPolarization  << G4endl;
220      G4cout << " MaterialPol. " << electronPolarization  << G4endl;
221      G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
222      G4cout << " Log. Volume  " << aLVolume->GetName() << G4endl;
223      G4cout << " Material     " << aMaterial          << G4endl;
224    }
225   
226    G4bool isOutRange;
227    G4int idx= CurrentMaterialCutsCoupleIndex();
228    G4double lAsymmetry = (*theAsymmetryTable)(idx)->
229                                  GetValue(positronEnergy, isOutRange);
230    G4double tAsymmetry = (*theTransverseAsymmetryTable)(idx)->
231                                  GetValue(positronEnergy, isOutRange);
232
233    G4double polZZ = positronPolarization.z()*
234      electronPolarization*positronDirection0;
235    G4double polXX = positronPolarization.x()*
236      electronPolarization*G4PolarizationHelper::GetParticleFrameX(positronDirection0);
237    G4double polYY = positronPolarization.y()*
238      electronPolarization*G4PolarizationHelper::GetParticleFrameY(positronDirection0);
239
240    G4double impact = 1. + polZZ*lAsymmetry + (polXX + polYY)*tAsymmetry;
241
242    mfp *= 1. / impact;
243
244    if (verboseLevel>=2) {
245      G4cout << " MeanFreePath:  " << mfp / mm << " mm " << G4endl;
246      G4cout << " Asymmetry:     " << lAsymmetry << ", " << tAsymmetry  << G4endl;
247      G4cout << " PolProduct:    " << polXX << ", " << polYY << ", " << polZZ << G4endl;
248    }
249  }
250 
251  return mfp;
252}
253//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
254
255void G4eplusPolarizedAnnihilation::BuildPhysicsTable(const G4ParticleDefinition& pd) 
256{
257  G4VEmProcess::BuildPhysicsTable(pd);
258  BuildAsymmetryTable(pd); 
259}
260//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
261
262void G4eplusPolarizedAnnihilation::PreparePhysicsTable(const G4ParticleDefinition& pd)
263{
264  G4VEmProcess::PreparePhysicsTable(pd);
265  theAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theAsymmetryTable);
266  theTransverseAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theTransverseAsymmetryTable);
267}
268
269void G4eplusPolarizedAnnihilation::BuildAsymmetryTable(const G4ParticleDefinition& part)
270{
271  // Access to materials
272  const G4ProductionCutsTable* theCoupleTable=
273        G4ProductionCutsTable::GetProductionCutsTable();
274  size_t numOfCouples = theCoupleTable->GetTableSize();
275  G4cout<<" annih-numOfCouples="<<numOfCouples<<"\n";
276  for(size_t i=0; i<numOfCouples; ++i) {
277    G4cout<<"annih- "<<i<<"/"<<numOfCouples<<"\n";
278    if (!theAsymmetryTable) break;
279    G4cout<<"annih- "<<theAsymmetryTable->GetFlag(i)<<"\n";
280    if (theAsymmetryTable->GetFlag(i)) {
281     G4cout<<" building pol-annih ... \n";
282
283      // create physics vector and fill it
284      const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple(i);
285
286      // use same parameters as for lambda
287      G4PhysicsVector* aVector = LambdaPhysicsVector(couple);
288      G4PhysicsVector* tVector = LambdaPhysicsVector(couple);
289
290      for (G4int j = 0 ; j < LambdaBinning() ; ++j ) {
291        G4double lowEdgeEnergy = aVector->GetLowEdgeEnergy(j);
292        G4double tasm=0.;
293        G4double asym = ComputeAsymmetry(lowEdgeEnergy, couple, part, 0., tasm);
294        aVector->PutValue(j,asym);
295        tVector->PutValue(j,tasm);
296      }
297
298      G4PhysicsTableHelper::SetPhysicsVector(theAsymmetryTable, i, aVector);
299      G4PhysicsTableHelper::SetPhysicsVector(theTransverseAsymmetryTable, i, tVector);
300    }
301  }
302
303}
304
305
306//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
307
308G4double G4eplusPolarizedAnnihilation::ComputeAsymmetry(G4double energy,
309                            const G4MaterialCutsCouple* couple,
310                            const G4ParticleDefinition& aParticle,
311                            G4double cut,
312                            G4double &tAsymmetry)
313{
314 G4double lAsymmetry = 0.0;
315          tAsymmetry = 0.0;
316
317 // calculate polarized cross section
318 theTargetPolarization=G4ThreeVector(0.,0.,1.);
319 emModel->SetTargetPolarization(theTargetPolarization);
320 emModel->SetBeamPolarization(theTargetPolarization);
321 G4double sigma2=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
322
323 // calculate transversely polarized cross section
324 theTargetPolarization=G4ThreeVector(1.,0.,0.);
325 emModel->SetTargetPolarization(theTargetPolarization);
326 emModel->SetBeamPolarization(theTargetPolarization);
327 G4double sigma3=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
328
329 // calculate unpolarized cross section
330 theTargetPolarization=G4ThreeVector();
331 emModel->SetTargetPolarization(theTargetPolarization);
332 emModel->SetBeamPolarization(theTargetPolarization);
333 G4double sigma0=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
334
335 // determine assymmetries
336  if (sigma0>0.) {
337    lAsymmetry=sigma2/sigma0-1.;
338    tAsymmetry=sigma3/sigma0-1.;
339                 }
340 return lAsymmetry;
341
342}
343
344
345
346//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
347
348void G4eplusPolarizedAnnihilation::PrintInfo()
349{
350  G4cout << "      Polarized model for annihilation into 2 photons"
351         << G4endl;
352}
353
354//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
355
356G4VParticleChange* G4eplusPolarizedAnnihilation::AtRestDoIt(const G4Track& aTrack,
357                                                     const G4Step& )
358//
359// Performs the e+ e- annihilation when both particles are assumed at rest.
360// It generates two back to back photons with energy = electron_mass.
361// The angular distribution is isotropic.
362// GEANT4 internal units
363//
364// Note : Effects due to binding of atomic electrons are negliged.
365{
366  fParticleChange.InitializeForPostStep(aTrack);
367
368  fParticleChange.SetNumberOfSecondaries(2);
369
370  G4double cosTeta = 2.*G4UniformRand()-1. , sinTeta = std::sqrt(1.-cosTeta*cosTeta);
371  G4double phi     = twopi * G4UniformRand();
372  G4ThreeVector direction (sinTeta*std::cos(phi), sinTeta*std::sin(phi), cosTeta);
373  fParticleChange.AddSecondary( new G4DynamicParticle (G4Gamma::Gamma(),
374                                            direction, electron_mass_c2) );
375  fParticleChange.AddSecondary( new G4DynamicParticle (G4Gamma::Gamma(),
376                                           -direction, electron_mass_c2) );
377  // Kill the incident positron
378  //
379  fParticleChange.ProposeTrackStatus(fStopAndKill);
380  return &fParticleChange;
381}
382
383//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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