source: trunk/source/processes/electromagnetic/polarisation/src/G4PolarizedCompton.cc @ 846

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26//
27// $Id: G4PolarizedCompton.cc,v 1.7 2007/07/10 09:35:37 schaelic Exp $
28// GEANT4 tag $Name: geant4-09-01-patch-02 $
29//
30//
31// File name:     G4PolarizedCompton
32//
33// Author:        Andreas Schaelicke
34//                based on code by Michel Maire / Vladimir IVANTCHENKO
35// Class description
36//
37// modified version respecting media and beam polarization
38//     using the stokes formalism
39//
40// Creation date: 01.05.2005
41//
42// Modifications:
43//
44// 01-01-05, include polarization description (A.Stahl)
45// 01-01-05, create asymmetry table and determine interactionlength (A.Stahl)
46// 01-05-05, update handling of media polarization (A.Schalicke)
47// 01-05-05, update polarized differential cross section (A.Schalicke)
48// 20-05-05, added polarization transfer (A.Schalicke)
49// 10-06-05, transformation between different reference frames (A.Schalicke)
50// 17-10-05, correct reference frame dependence in GetMeanFreePath (A.Schalicke)
51// 26-07-06, cross section recalculated (P.Starovoitov)
52// 09-08-06, make it work under current geant4 release (A.Schalicke)
53// 11-06-07, add PostStepGetPhysicalInteractionLength (A.Schalicke)
54// -----------------------------------------------------------------------------
55
56
57#include "G4PolarizedCompton.hh"
58#include "G4Electron.hh"
59
60#include "G4StokesVector.hh"
61#include "G4PolarizationManager.hh"
62#include "G4PolarizedComptonModel.hh"
63#include "G4ProductionCutsTable.hh"
64#include "G4PhysicsTableHelper.hh"
65#include "G4KleinNishinaCompton.hh"
66#include "G4PolarizedComptonModel.hh"
67
68//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
69
70G4PolarizedCompton::G4PolarizedCompton(const G4String& processName,
71  G4ProcessType type):
72  G4VEmProcess (processName, type),
73  buildAsymmetryTable(true),
74  useAsymmetryTable(true),
75  isInitialised(false),
76  selectedModel(0),
77  mType(10),
78  theAsymmetryTable(NULL)
79{
80  SetLambdaBinning(90);
81  SetMinKinEnergy(0.1*keV);
82  SetMaxKinEnergy(100.0*GeV);
83}
84
85//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
86 
87G4PolarizedCompton::~G4PolarizedCompton()
88{
89  if (theAsymmetryTable) {
90    theAsymmetryTable->clearAndDestroy();
91    delete theAsymmetryTable;
92  }
93}
94
95//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
96
97void G4PolarizedCompton::InitialiseProcess(const G4ParticleDefinition*)
98{
99  if(!isInitialised) {
100    isInitialised = true;
101    SetBuildTableFlag(true);
102    SetSecondaryParticle(G4Electron::Electron());
103    G4double emin = MinKinEnergy();
104    G4double emax = MaxKinEnergy();
105    emModel = new G4PolarizedComptonModel();
106    if(0 == mType) selectedModel = new G4KleinNishinaCompton();
107    else if(10 == mType) selectedModel = emModel;
108    selectedModel->SetLowEnergyLimit(emin);
109    selectedModel->SetHighEnergyLimit(emax);
110    AddEmModel(1, selectedModel);
111  } 
112}
113
114//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
115
116void G4PolarizedCompton::PrintInfo()
117{
118  G4cout << " Total cross sections has a good parametrisation"
119         << " from 10 KeV to (100/Z) GeV" 
120         << "\n      Sampling according " << selectedModel->GetName() << " model" 
121         << G4endl;
122}         
123
124//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
125
126void G4PolarizedCompton::SetModel(const G4String& s)
127{
128  if(s == "Klein-Nishina") mType = 0;
129  if(s == "Polarized-Compton") mType = 10;
130}
131
132
133//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
134//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
135
136
137
138G4double G4PolarizedCompton::GetMeanFreePath(
139                                   const G4Track& aTrack,
140                                   G4double   previousStepSize,
141                                   G4ForceCondition* condition)
142{
143  // *** get unploarised mean free path from lambda table ***
144  G4double mfp = G4VEmProcess::GetMeanFreePath(aTrack, previousStepSize, condition);
145
146
147   if (theAsymmetryTable && useAsymmetryTable) {
148     // *** get asymmetry, if target is polarized ***
149     const G4DynamicParticle* aDynamicGamma = aTrack.GetDynamicParticle();
150     const G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
151     const G4StokesVector GammaPolarization = aTrack.GetPolarization();
152     const G4ParticleMomentum GammaDirection0 = aDynamicGamma->GetMomentumDirection();
153
154     G4Material*         aMaterial = aTrack.GetMaterial();
155     G4VPhysicalVolume*  aPVolume  = aTrack.GetVolume();
156     G4LogicalVolume*    aLVolume  = aPVolume->GetLogicalVolume();
157
158     //   G4Material* bMaterial = aLVolume->GetMaterial();
159     G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
160
161     const G4bool VolumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
162     G4StokesVector ElectronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
163
164     if (!VolumeIsPolarized || mfp == DBL_MAX) return mfp;
165     
166     if (verboseLevel>=2) {
167
168       G4cout << " Mom " << GammaDirection0  << G4endl;
169       G4cout << " Polarization " << GammaPolarization  << G4endl;
170       G4cout << " MaterialPol. " << ElectronPolarization  << G4endl;
171       G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
172       G4cout << " Log. Volume  " << aLVolume->GetName() << G4endl;
173       G4cout << " Material     " << aMaterial          << G4endl;
174     }
175
176     G4int midx= CurrentMaterialCutsCoupleIndex();
177     G4PhysicsVector * aVector=(*theAsymmetryTable)(midx);
178     
179     G4double asymmetry=0;
180     if (aVector) {
181       G4bool isOutRange;
182       asymmetry = aVector->GetValue(GammaEnergy, isOutRange);
183     } else {
184       G4cout << " MaterialIndex     " << midx << " is out of range \n";
185       asymmetry=0;
186     }
187
188     //  we have to determine angle between particle motion
189     //  and target polarisation here 
190     //      circ pol * Vec(ElectronPol)*Vec(PhotonMomentum)
191     //  both vectors in global reference frame
192     
193     G4double pol=ElectronPolarization*GammaDirection0;
194     
195     G4double polProduct = GammaPolarization.p3() * pol;
196     mfp *= 1. / ( 1. + polProduct * asymmetry );
197
198     if (verboseLevel>=2) {
199       G4cout << " MeanFreePath:  " << mfp / mm << " mm " << G4endl;
200       G4cout << " Asymmetry:     " << asymmetry          << G4endl;
201       G4cout << " PolProduct:    " << polProduct         << G4endl;
202     }
203   }
204
205   return mfp;
206}
207
208G4double G4PolarizedCompton::PostStepGetPhysicalInteractionLength(
209                                   const G4Track& aTrack,
210                                   G4double   previousStepSize,
211                                   G4ForceCondition* condition)
212{
213  // *** get unploarised mean free path from lambda table ***
214  G4double mfp = G4VEmProcess::PostStepGetPhysicalInteractionLength(aTrack, previousStepSize, condition);
215
216
217   if (theAsymmetryTable && useAsymmetryTable) {
218     // *** get asymmetry, if target is polarized ***
219     const G4DynamicParticle* aDynamicGamma = aTrack.GetDynamicParticle();
220     const G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
221     const G4StokesVector GammaPolarization = aTrack.GetPolarization();
222     const G4ParticleMomentum GammaDirection0 = aDynamicGamma->GetMomentumDirection();
223
224     G4Material*         aMaterial = aTrack.GetMaterial();
225     G4VPhysicalVolume*  aPVolume  = aTrack.GetVolume();
226     G4LogicalVolume*    aLVolume  = aPVolume->GetLogicalVolume();
227
228     //   G4Material* bMaterial = aLVolume->GetMaterial();
229     G4PolarizationManager * polarizationManger = G4PolarizationManager::GetInstance();
230
231     const G4bool VolumeIsPolarized = polarizationManger->IsPolarized(aLVolume);
232     G4StokesVector ElectronPolarization = polarizationManger->GetVolumePolarization(aLVolume);
233
234     if (!VolumeIsPolarized || mfp == DBL_MAX) return mfp;
235     
236     if (verboseLevel>=2) {
237
238       G4cout << " Mom " << GammaDirection0  << G4endl;
239       G4cout << " Polarization " << GammaPolarization  << G4endl;
240       G4cout << " MaterialPol. " << ElectronPolarization  << G4endl;
241       G4cout << " Phys. Volume " << aPVolume->GetName() << G4endl;
242       G4cout << " Log. Volume  " << aLVolume->GetName() << G4endl;
243       G4cout << " Material     " << aMaterial          << G4endl;
244     }
245
246     G4int midx= CurrentMaterialCutsCoupleIndex();
247     G4PhysicsVector * aVector=(*theAsymmetryTable)(midx);
248     
249     G4double asymmetry=0;
250     if (aVector) {
251       G4bool isOutRange;
252       asymmetry = aVector->GetValue(GammaEnergy, isOutRange);
253     } else {
254       G4cout << " MaterialIndex     " << midx << " is out of range \n";
255       asymmetry=0;
256     }
257
258     //  we have to determine angle between particle motion
259     //  and target polarisation here 
260     //      circ pol * Vec(ElectronPol)*Vec(PhotonMomentum)
261     //  both vectors in global reference frame
262     
263     G4double pol=ElectronPolarization*GammaDirection0;
264     
265     G4double polProduct = GammaPolarization.p3() * pol;
266     mfp *= 1. / ( 1. + polProduct * asymmetry );
267
268     if (verboseLevel>=2) {
269       G4cout << " MeanFreePath:  " << mfp / mm << " mm " << G4endl;
270       G4cout << " Asymmetry:     " << asymmetry          << G4endl;
271       G4cout << " PolProduct:    " << polProduct         << G4endl;
272     }
273   }
274
275   return mfp;
276}
277
278//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
279
280void G4PolarizedCompton::PreparePhysicsTable(const G4ParticleDefinition& part)
281{
282  G4VEmProcess::PreparePhysicsTable(part);
283  if(buildAsymmetryTable)
284    theAsymmetryTable = G4PhysicsTableHelper::PreparePhysicsTable(theAsymmetryTable);
285}
286
287//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
288
289
290void G4PolarizedCompton::BuildPhysicsTable(const G4ParticleDefinition& part)
291{
292  // *** build (unpolarized) cross section tables (Lambda)
293  G4VEmProcess::BuildPhysicsTable(part);
294  if(buildAsymmetryTable)
295    BuildAsymmetryTable(part);
296}
297
298//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
299
300
301void G4PolarizedCompton::BuildAsymmetryTable(const G4ParticleDefinition& part)
302{
303  // Access to materials
304  const G4ProductionCutsTable* theCoupleTable=
305        G4ProductionCutsTable::GetProductionCutsTable();
306  size_t numOfCouples = theCoupleTable->GetTableSize();
307  for(size_t i=0; i<numOfCouples; ++i) {
308    if (!theAsymmetryTable) break;
309    if (theAsymmetryTable->GetFlag(i)) {
310
311      // create physics vector and fill it
312      const G4MaterialCutsCouple* couple = theCoupleTable->GetMaterialCutsCouple(i);
313      // use same parameters as for lambda
314      G4PhysicsVector* aVector = LambdaPhysicsVector(couple);
315      //      modelManager->FillLambdaVector(aVector, couple, startFromNull);
316
317      for (G4int j = 0 ; j < LambdaBinning() ; ++j ) {
318        G4double lowEdgeEnergy = aVector->GetLowEdgeEnergy(j);
319        G4double tasm=0.;
320        G4double asym = ComputeAsymmetry(lowEdgeEnergy, couple, part, 0., tasm);
321        aVector->PutValue(j,asym);
322      }
323
324      G4PhysicsTableHelper::SetPhysicsVector(theAsymmetryTable, i, aVector);
325    }
326  }
327
328}
329
330//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
331
332
333G4double G4PolarizedCompton::ComputeAsymmetry(G4double energy,
334                         const G4MaterialCutsCouple* couple,
335                       const G4ParticleDefinition& aParticle,
336                               G4double cut,
337                               G4double & tAsymmetry)
338{
339  G4double lAsymmetry = 0.0;
340  tAsymmetry=0;
341
342  //
343  // calculate polarized cross section
344  //
345  G4ThreeVector thePolarization=G4ThreeVector(0.,0.,1.);
346  emModel->SetTargetPolarization(thePolarization);
347  emModel->SetBeamPolarization(thePolarization);
348  G4double sigma2=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
349
350  //
351  // calculate unpolarized cross section
352  //
353  thePolarization=G4ThreeVector();
354  emModel->SetTargetPolarization(thePolarization);
355  emModel->SetBeamPolarization(thePolarization);
356  G4double sigma0=emModel->CrossSection(couple,&aParticle,energy,cut,energy);
357
358  // determine assymmetries
359  if (sigma0>0.) {
360    lAsymmetry=sigma2/sigma0-1.;
361  }
362  return lAsymmetry;
363}
364
365//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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