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26 //
27 /// \file GB04BOptnBremSplitting.cc
28 /// \brief Implementation of the GB04BOptnBremSplitting class
29
30 #include "GB04BOptnBremSplitting.hh"
31
32 #include "G4BiasingProcessInterface.hh"
33 #include "G4ParticleChangeForLoss.hh"
34
35 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
36
37 GB04BOptnBremSplitting::GB04BOptnBremSplitting(G4String name)
38 : G4VBiasingOperation(name), fSplittingFactor(1), fParticleChange()
39 {}
40
41 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
42
43 GB04BOptnBremSplitting::~GB04BOptnBremSplitting() {}
44
45 G4VParticleChange*
46 GB04BOptnBremSplitting::ApplyFinalStateBiasing(const G4BiasingProcessInterface* callingProcess,
47 const G4Track* track, const G4Step* step, G4bool&)
48 {
49 // -- Collect brem. process (wrapped process) final state:
50 G4VParticleChange* processFinalState =
51 callingProcess->GetWrappedProcess()->PostStepDoIt(*track, *step);
52
53 // -- if no splitting requested, let the brem. process to return directly its
54 // -- generated final state:
55 if (fSplittingFactor == 1) return processFinalState;
56
57 // -- a special case here: the brem. process corrects for cross-section change
58 // -- over the step due to energy loss by sometimes "abandoning" the interaction,
59 // -- returning an unchanged incoming electron/positron.
60 // -- We respect this correction, and if no secondary is produced, its means this
61 // -- case is happening:
62 if (processFinalState->GetNumberOfSecondaries() == 0) return processFinalState;
63
64 // -- Now start the biasing:
65 // -- - the electron state will be taken as the first one produced by the brem.
66 // -- process, hence the one stored in above processFinalState particle change.
67 // -- This state will be stored in our fParticleChange object.
68 // -- - the photon accompagnying the electron will be stored also this way.
69 // -- - we will then do fSplittingFactor - 1 call to the brem. process to collect
70 // -- fSplittingFactor - 1 additionnal gammas. All these will be stored in our
71 // -- fParticleChange object.
72
73 // -- We called the brem. process above. Its concrete particle change is indeed
74 // -- a "G4ParticleChangeForLoss" object. We cast this particle change to access
75 // -- methods of the concrete G4ParticleChangeForLoss type:
76 G4ParticleChangeForLoss* actualParticleChange = (G4ParticleChangeForLoss*)processFinalState;
77
78 fParticleChange.Initialize(*track);
79
80 // -- Store electron final state:
81 fParticleChange.ProposeTrackStatus(actualParticleChange->GetTrackStatus());
82 fParticleChange.ProposeEnergy(actualParticleChange->GetProposedKineticEnergy());
83 fParticleChange.ProposeMomentumDirection(actualParticleChange->GetProposedMomentumDirection());
84
85 // -- Now deal with the gamma's:
86 // -- their common weight:
87 G4double gammaWeight = track->GetWeight() / fSplittingFactor;
88
89 // -- inform we will have fSplittingFactor gamma's:
90 fParticleChange.SetNumberOfSecondaries(fSplittingFactor);
91
92 // -- inform we take care of secondaries weight (otherwise these
93 // -- secondaries are by default given the primary weight).
94 fParticleChange.SetSecondaryWeightByProcess(true);
95
96 // -- Store first gamma:
97 G4Track* gammaTrack = actualParticleChange->GetSecondary(0);
98 gammaTrack->SetWeight(gammaWeight);
99 fParticleChange.AddSecondary(gammaTrack);
100 // -- and clean-up the brem. process particle change:
101 actualParticleChange->Clear();
102
103 // -- now start the fSplittingFactor-1 calls to the brem. process to store each
104 // -- related gamma:
105 G4int nCalls = 1;
106 while (nCalls < fSplittingFactor) {
107 // ( note: we don't need to cast to actual type here, as methods for accessing
108 // secondary particles are from base class G4VParticleChange )
109 processFinalState = callingProcess->GetWrappedProcess()->PostStepDoIt(*track, *step);
110 if (processFinalState->GetNumberOfSecondaries() == 1) {
111 gammaTrack = processFinalState->GetSecondary(0);
112 gammaTrack->SetWeight(gammaWeight);
113 fParticleChange.AddSecondary(gammaTrack);
114 nCalls++;
115 }
116 // -- very rare special case: we ignore for now.
117 else if (processFinalState->GetNumberOfSecondaries() > 1) {
118 for (G4int i = 0; i < processFinalState->GetNumberOfSecondaries(); i++)
119 delete processFinalState->GetSecondary(i);
120 }
121 processFinalState->Clear();
122 }
123
124 // -- we are done:
125 return &fParticleChange;
126 }
127
128 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
129