source: trunk/source/processes/electromagnetic/lowenergy/src/G4PenelopePhotoElectricModel.cc @ 1168

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26// $Id: G4PenelopePhotoElectricModel.cc,v 1.6 2009/05/19 14:57:01 pandola Exp $
27// GEANT4 tag $Name: geant4-09-03-beta-cand-01 $
28//
29// Author: Luciano Pandola
30//
31// History:
32// --------
33// 08 Oct 2008   L Pandola  Migration from process to model
34// 08 Jan 2009   L Pandola  Check shell index to avoid mismatch between
35//                          the Penelope cross section database and the
36//                          G4AtomicTransitionManager database. It suppresses
37//                          a warning from G4AtomicTransitionManager only.
38//                          Results are unchanged.
39// 25 Mar 2009   L Pandola  Small fix to avoid wrong energy-violation warnings
40// 17 Apr 2009   V Ivanchenko Cleanup initialisation and generation of secondaries:
41//                  - apply internal high-energy limit only in constructor
42//                  - do not apply low-energy limit (default is 0)
43//                  - do not apply production threshold on secondaries
44// 19 May 2009   L Pandola    Explicitely set to zero pointers deleted in
45//                            Initialise(), since they might be checked later on
46//
47
48#include "G4PenelopePhotoElectricModel.hh"
49#include "G4ParticleDefinition.hh"
50#include "G4MaterialCutsCouple.hh"
51#include "G4ProductionCutsTable.hh"
52#include "G4DynamicParticle.hh"
53#include "G4PhysicsTable.hh"
54#include "G4ElementTable.hh"
55#include "G4Element.hh"
56#include "G4CrossSectionHandler.hh"
57#include "G4AtomicTransitionManager.hh"
58#include "G4AtomicShell.hh"
59#include "G4Gamma.hh"
60#include "G4Electron.hh"
61
62//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
63
64
65G4PenelopePhotoElectricModel::G4PenelopePhotoElectricModel(const G4ParticleDefinition*,
66                                             const G4String& nam)
67  :G4VEmModel(nam),isInitialised(false),crossSectionHandler(0),
68   shellCrossSectionHandler(0)
69{
70  fIntrinsicLowEnergyLimit = 100.0*eV;
71  fIntrinsicHighEnergyLimit = 100.0*GeV;
72  //  SetLowEnergyLimit(fIntrinsicLowEnergyLimit);
73  SetHighEnergyLimit(fIntrinsicHighEnergyLimit);
74  //
75  fUseAtomicDeexcitation = true;
76  verboseLevel= 0;
77  // Verbosity scale:
78  // 0 = nothing
79  // 1 = warning for energy non-conservation
80  // 2 = details of energy budget
81  // 3 = calculation of cross sections, file openings, sampling of atoms
82  // 4 = entering in methods
83}
84
85//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
86
87G4PenelopePhotoElectricModel::~G4PenelopePhotoElectricModel()
88{ 
89  if (crossSectionHandler) delete crossSectionHandler;
90  if (shellCrossSectionHandler) delete shellCrossSectionHandler;
91}
92
93//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
94
95void G4PenelopePhotoElectricModel::Initialise(const G4ParticleDefinition*,
96                                       const G4DataVector& )
97{
98  if (verboseLevel > 3)
99    G4cout << "Calling  G4PenelopePhotoElectricModel::Initialise()" << G4endl;
100  if (crossSectionHandler)
101    {
102      crossSectionHandler->Clear();
103      delete crossSectionHandler;
104      crossSectionHandler = 0;
105    }
106  if (shellCrossSectionHandler)
107    {
108      shellCrossSectionHandler->Clear();
109      delete shellCrossSectionHandler;
110      shellCrossSectionHandler =0;
111    }
112
113  //Re-initialize cross section handlers
114  crossSectionHandler = new G4CrossSectionHandler();
115  crossSectionHandler->Clear();
116  G4String crossSectionFile = "penelope/ph-cs-pen-";
117  crossSectionHandler->LoadData(crossSectionFile);
118  shellCrossSectionHandler = new G4CrossSectionHandler();
119  shellCrossSectionHandler->Clear();
120  crossSectionFile = "penelope/ph-ss-cs-pen-";
121  shellCrossSectionHandler->LoadShellData(crossSectionFile);
122  //This is used to retrieve cross section values later on
123  crossSectionHandler->BuildMeanFreePathForMaterials();
124
125  if (verboseLevel > 2) 
126    G4cout << "Loaded cross section files for PenelopePhotoElectric" << G4endl;
127
128  if (verboseLevel > 0) { 
129    G4cout << "Penelope Photo-Electric model is initialized " << G4endl
130           << "Energy range: "
131           << LowEnergyLimit() / MeV << " MeV - "
132           << HighEnergyLimit() / GeV << " GeV"
133           << G4endl;
134  }
135
136  if(isInitialised) return;
137  fParticleChange = GetParticleChangeForGamma();
138  isInitialised = true;
139}
140
141//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
142
143G4double G4PenelopePhotoElectricModel::ComputeCrossSectionPerAtom(
144                                       const G4ParticleDefinition*,
145                                             G4double energy,
146                                             G4double Z, G4double,
147                                             G4double, G4double)
148{
149  //
150  // Penelope model. Use data-driven approach for cross section estimate (and
151  // also shell sampling from a given atom). Data are from the Livermore database
152  //  D.E. Cullen et al., Report UCRL-50400 (1989)
153  //
154
155  if (verboseLevel > 3)
156    G4cout << "Calling ComputeCrossSectionPerAtom() of G4PenelopePhotoElectricModel" << G4endl;
157
158  G4int iZ = (G4int) Z;
159  //  if (!crossSectionHandler) // VI: should not be
160  //  {
161  //    G4cout << "G4PenelopePhotoElectricModel::ComputeCrossSectionPerAtom" << G4endl;
162  //    G4cout << "The cross section handler is not correctly initialized" << G4endl;
163  //    G4Exception();
164  //  }
165  G4double cs = crossSectionHandler->FindValue(iZ,energy);
166 
167  if (verboseLevel > 2)
168    G4cout << "Photoelectric cross section at " << energy/MeV << " MeV for Z=" << Z <<
169      " = " << cs/barn << " barn" << G4endl;
170  return cs;
171}
172
173//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
174
175void G4PenelopePhotoElectricModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
176                                              const G4MaterialCutsCouple* couple,
177                                              const G4DynamicParticle* aDynamicGamma,
178                                              G4double,
179                                              G4double)
180{
181  //
182  // Photoelectric effect, Penelope model
183  //
184  // The target atom and the target shell are sampled according to the Livermore
185  // database
186  //  D.E. Cullen et al., Report UCRL-50400 (1989)
187  // The angular distribution of the electron in the final state is sampled
188  // according to the Sauter distribution from
189  //  F. Sauter, Ann. Phys. 11 (1931) 454
190  // The energy of the final electron is given by the initial photon energy minus
191  // the binding energy. Fluorescence de-excitation is subsequently produced
192  // (to fill the vacancy) according to the general Geant4 G4DeexcitationManager:
193  //  J. Stepanek, Comp. Phys. Comm. 1206 pp 1-1-9 (1997)
194
195  if (verboseLevel > 3)
196    G4cout << "Calling SamplingSecondaries() of G4PenelopePhotoElectricModel" << G4endl;
197
198  G4double photonEnergy = aDynamicGamma->GetKineticEnergy();
199
200  // always kill primary
201  fParticleChange->ProposeTrackStatus(fStopAndKill);
202  fParticleChange->SetProposedKineticEnergy(0.);
203
204  if (photonEnergy <= fIntrinsicLowEnergyLimit)
205    {
206      fParticleChange->ProposeLocalEnergyDeposit(photonEnergy);
207      return ;
208    }
209
210  G4ParticleMomentum photonDirection = aDynamicGamma->GetMomentumDirection();
211
212  // Select randomly one element in the current material
213  if (verboseLevel > 2)
214    G4cout << "Going to select element in " << couple->GetMaterial()->GetName() << G4endl;
215  //use crossSectionHandler instead of G4EmElementSelector because in this case
216  //the dimension of the table is equal to the dimension of the database
217  //(less interpolation errors)
218  G4int Z = crossSectionHandler->SelectRandomAtom(couple,photonEnergy);
219  if (verboseLevel > 2)
220    G4cout << "Selected Z = " << Z << G4endl;
221
222  // Select the ionised shell in the current atom according to shell cross sections
223  size_t shellIndex = shellCrossSectionHandler->SelectRandomShell(Z,photonEnergy);
224
225  // Retrieve the corresponding identifier and binding energy of the selected shell
226  const G4AtomicTransitionManager* transitionManager = G4AtomicTransitionManager::Instance();
227
228  //The number of shell cross section possibly reported in the Penelope database
229  //might be different from the number of shells in the G4AtomicTransitionManager
230  //(namely, Penelope may contain more shell, especially for very light elements).
231  //In order to avoid a warning message from the G4AtomicTransitionManager, I
232  //add this protection. Results are anyway changed, because when G4AtomicTransitionManager
233  //has a shellID>maxID, it sets the shellID to the last valid shell.
234  size_t numberOfShells = (size_t) transitionManager->NumberOfShells(Z);
235  if (shellIndex >= numberOfShells)
236    shellIndex = numberOfShells-1;
237
238  const G4AtomicShell* shell = transitionManager->Shell(Z,shellIndex);
239  G4double bindingEnergy = shell->BindingEnergy();
240  G4int shellId = shell->ShellId();
241
242  G4double localEnergyDeposit = 0.0;
243
244  // Primary outcoming electron
245  G4double eKineticEnergy = photonEnergy - bindingEnergy;
246 
247  // There may be cases where the binding energy of the selected shell is > photon energy
248  // In such cases do not generate secondaries
249  if (eKineticEnergy > 0.)
250    {
251      //Now check if the electron is above cuts: if so, it is created explicitely
252      //VI: checking cut here provides inconsistency in testing
253      //      if (eKineticEnergy > cutE)
254      // The electron is created
255      // Direction sampled from the Sauter distribution
256      G4double cosTheta = SampleElectronDirection(eKineticEnergy);
257      G4double sinTheta = std::sqrt(1-cosTheta*cosTheta);
258      G4double phi = twopi * G4UniformRand() ;
259      G4double dirx = sinTheta * std::cos(phi);
260      G4double diry = sinTheta * std::sin(phi);
261      G4double dirz = cosTheta ;
262      G4ThreeVector electronDirection(dirx,diry,dirz); //electron direction
263      electronDirection.rotateUz(photonDirection);
264      G4DynamicParticle* electron = new G4DynamicParticle (G4Electron::Electron(), 
265                                                           electronDirection, 
266                                                           eKineticEnergy);
267      fvect->push_back(electron);
268    } 
269  //  else
270  //  {
271  //    localEnergyDeposit += eKineticEnergy;   
272  //    eKineticEnergy = 0;
273  //  }
274  //  }
275  else
276    {
277      bindingEnergy = photonEnergy;
278    }
279  G4double energyInFluorescence = 0; //testing purposes
280
281  //Now, take care of fluorescence, if required
282  if(DeexcitationFlag() && Z > 5) 
283    {
284      const G4ProductionCutsTable* theCoupleTable=
285        G4ProductionCutsTable::GetProductionCutsTable();
286      size_t indx = couple->GetIndex();
287      G4double cutG = (*(theCoupleTable->GetEnergyCutsVector(0)))[indx];
288      G4double cutE = (*(theCoupleTable->GetEnergyCutsVector(1)))[indx];
289     
290      // Protection to avoid generating photons in the unphysical case of
291      // shell binding energy > photon energy
292      if (bindingEnergy > cutG || bindingEnergy > cutE)
293        {
294          deexcitationManager.SetCutForSecondaryPhotons(cutG);
295          deexcitationManager.SetCutForAugerElectrons(cutE);
296          std::vector<G4DynamicParticle*>* photonVector = 
297            deexcitationManager.GenerateParticles(Z,shellId); 
298          //Check for secondaries
299          if(photonVector) 
300            {
301              for (size_t k=0; k< photonVector->size(); k++)
302                {
303                  G4DynamicParticle* aPhoton = (*photonVector)[k];
304                  if (aPhoton)
305                    {
306                      G4double itsEnergy = aPhoton->GetKineticEnergy();
307                      if (itsEnergy <= bindingEnergy)
308                        {
309                          if(aPhoton->GetDefinition() == G4Gamma::Gamma())
310                            energyInFluorescence += itsEnergy;
311                          bindingEnergy -= itsEnergy;
312                          fvect->push_back(aPhoton);
313                        }
314                      else
315                        {
316                          delete aPhoton;
317                          (*photonVector)[k] = 0;
318                        }
319                    }
320                }
321              delete photonVector;
322            }
323        }
324    }
325  //Residual energy is deposited locally
326  localEnergyDeposit += bindingEnergy;
327     
328  if (localEnergyDeposit < 0)
329    {
330      G4cout << "WARNING - "
331             << "G4PenelopePhotoElectric::PostStepDoIt - Negative energy deposit"
332             << G4endl;
333      localEnergyDeposit = 0;
334    }
335
336  fParticleChange->ProposeLocalEnergyDeposit(localEnergyDeposit);
337
338  if (verboseLevel > 1)
339    {
340      G4cout << "-----------------------------------------------------------" << G4endl;
341      G4cout << "Energy balance from G4PenelopePhotoElectric" << G4endl;
342      G4cout << "Incoming photon energy: " << photonEnergy/keV << " keV" << G4endl;
343      G4cout << "-----------------------------------------------------------" << G4endl;
344      if (eKineticEnergy)
345        G4cout << "Outgoing electron " << eKineticEnergy/keV << " keV" << G4endl;
346      G4cout << "Fluorescence: " << energyInFluorescence/keV << " keV" << G4endl;
347      G4cout << "Local energy deposit " << localEnergyDeposit/keV << " keV" << G4endl;
348      G4cout << "Total final state: " << (eKineticEnergy+energyInFluorescence+localEnergyDeposit)/keV << 
349        " keV" << G4endl;
350      G4cout << "-----------------------------------------------------------" << G4endl;
351    }
352  if (verboseLevel > 0)
353    {
354      G4double energyDiff = 
355        std::fabs(eKineticEnergy+energyInFluorescence+localEnergyDeposit-photonEnergy);
356      if (energyDiff > 0.05*keV)
357        G4cout << "Warning from G4PenelopePhotoElectric: problem with energy conservation: " << 
358          (eKineticEnergy+energyInFluorescence+localEnergyDeposit)/keV
359               << " keV (final) vs. " << 
360          photonEnergy/keV << " keV (initial)" << G4endl;
361    }
362}
363
364//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
365
366void G4PenelopePhotoElectricModel::ActivateAuger(G4bool augerbool)
367{
368  if (!fUseAtomicDeexcitation)
369    {
370      G4cout << "WARNING - G4PenelopePhotoElectricModel" << G4endl;
371      G4cout << "The use of the Atomic Deexcitation Manager is set to false " << G4endl;
372      G4cout << "Therefore, Auger electrons will be not generated anyway" << G4endl;
373    }
374  deexcitationManager.ActivateAugerElectronProduction(augerbool);
375  if (verboseLevel > 1)
376    G4cout << "Auger production set to " << augerbool << G4endl;
377}
378
379//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
380
381G4double G4PenelopePhotoElectricModel::SampleElectronDirection(G4double energy)
382{
383  G4double costheta = 1.0;
384  if (energy>1*GeV) return costheta;
385 
386  //1) initialize energy-dependent variables
387  // Variable naming according to Eq. (2.24) of Penelope Manual
388  // (pag. 44)
389  G4double gamma = 1.0 + energy/electron_mass_c2;
390  G4double gamma2 = gamma*gamma;
391  G4double beta = std::sqrt((gamma2-1.0)/gamma2);
392   
393  // ac corresponds to "A" of Eq. (2.31)
394  //
395  G4double ac = (1.0/beta) - 1.0;
396  G4double a1 = 0.5*beta*gamma*(gamma-1.0)*(gamma-2.0);
397  G4double a2 = ac + 2.0;
398  G4double gtmax = 2.0*(a1 + 1.0/ac);
399 
400  G4double tsam = 0;
401  G4double gtr = 0;
402
403  //2) sampling. Eq. (2.31) of Penelope Manual
404  // tsam = 1-std::cos(theta)
405  // gtr = rejection function according to Eq. (2.28)
406  do{
407    G4double rand = G4UniformRand();
408    tsam = 2.0*ac * (2.0*rand + a2*std::sqrt(rand)) / (a2*a2 - 4.0*rand);
409    gtr = (2.0 - tsam) * (a1 + 1.0/(ac+tsam));
410  }while(G4UniformRand()*gtmax > gtr);
411  costheta = 1.0-tsam;
412  return costheta;
413}
414
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