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25 //
26 /// \file processes/phonon/src/G4VPhononProcess.cc
27 /// \brief Implementation of the G4VPhononProcess base class
28 //
29 //
30 // 20131111 Add verbosity to report creating secondaries
31
32 #include "G4VPhononProcess.hh"
33 #include "G4DynamicParticle.hh"
34 #include "G4ExceptionSeverity.hh"
35 #include "G4LatticeManager.hh"
36 #include "G4LatticePhysical.hh"
37 #include "G4ParticleDefinition.hh"
38 #include "G4PhononLong.hh"
39 #include "G4PhononPolarization.hh"
40 #include "G4PhononTrackMap.hh"
41 #include "G4PhononTransFast.hh"
42 #include "G4PhononTransSlow.hh"
43 #include "G4ProcessType.hh"
44 #include "G4ThreeVector.hh"
45 #include "G4Track.hh"
46
47 namespace {
48 const G4ThreeVector nullVec(0.,0.,0.); // For convenience below
49 }
50
51 // Constructor and destructor
52
53 G4VPhononProcess::G4VPhononProcess(const G4String& processName)
54 : G4VDiscreteProcess(processName, fPhonon),
55 trackKmap(G4PhononTrackMap::GetInstance()), theLattice(0),
56 currentTrack(0) {}
57
58 G4VPhononProcess::~G4VPhononProcess() {;}
59
60
61 // Only applies to the known phonon polarization states
62
63 G4bool G4VPhononProcess::IsApplicable(const G4ParticleDefinition& aPD) {
64 return (&aPD==G4PhononLong::Definition() ||
65 &aPD==G4PhononTransFast::Definition() ||
66 &aPD==G4PhononTransSlow::Definition() );
67 }
68
69
70 // Initialize wave vectors for currently active track(s)
71
72 void G4VPhononProcess::StartTracking(G4Track* track) {
73 G4VProcess::StartTracking(track); // Apply base class actions
74
75 // FIXME: THE WAVEVECTOR SHOULD BE COMPUTED BY INVERTING THE K/V MAP
76 if (!trackKmap->Find(track))
77 trackKmap->SetK(track, track->GetMomentumDirection());
78
79 currentTrack = track; // Save for use by EndTracking
80
81 // Fetch lattice for current track once, use in subsequent steps
82 G4LatticeManager* LM = G4LatticeManager::GetLatticeManager();
83 theLattice = LM->GetLattice(track->GetVolume());
84 }
85
86 void G4VPhononProcess::EndTracking() {
87 G4VProcess::EndTracking(); // Apply base class actions
88 trackKmap->RemoveTrack(currentTrack);
89 currentTrack = 0;
90 theLattice = 0;
91 }
92
93
94 // For convenience, map phonon type to polarization code
95
96 G4int G4VPhononProcess::GetPolarization(const G4Track& track) const {
97 return G4PhononPolarization::Get(track.GetParticleDefinition());
98 }
99
100
101 // Generate random polarization from density of states
102
103 G4int G4VPhononProcess::ChoosePolarization(G4double Ldos, G4double STdos,
104 G4double FTdos) const {
105 G4double norm = Ldos + STdos + FTdos;
106 G4double cProbST = STdos/norm;
107 G4double cProbFT = FTdos/norm + cProbST;
108
109 // NOTE: Order of selection done to match previous random sequences
110 G4double modeMixer = G4UniformRand();
111 if (modeMixer<cProbST) return G4PhononPolarization::TransSlow;
112 if (modeMixer<cProbFT) return G4PhononPolarization::TransFast;
113 return G4PhononPolarization::Long;
114 }
115
116
117 // Create new secondary track from phonon configuration
118
119 G4Track* G4VPhononProcess::CreateSecondary(G4int polarization,
120 const G4ThreeVector& waveVec,
121 G4double energy) const {
122 if (verboseLevel>1) {
123 G4cout << GetProcessName() << " CreateSecondary pol " << polarization
124 << " K " << waveVec << " E " << energy << G4endl;
125 }
126
127 G4ThreeVector vgroup = theLattice->MapKtoVDir(polarization, waveVec);
128 if (verboseLevel>1) G4cout << " MapKtoVDir returned " << vgroup << G4endl;
129
130 vgroup = theLattice->RotateToGlobal(vgroup);
131 if (verboseLevel>1) G4cout << " RotateToGlobal returned " << vgroup << G4endl;
132
133 if (verboseLevel && std::fabs(vgroup.mag()-1.) > 0.01) {
134 G4cout << "WARNING: " << GetProcessName() << " vgroup not a unit vector: "
135 << vgroup << G4endl;
136 }
137
138 G4ParticleDefinition* thePhonon = G4PhononPolarization::Get(polarization);
139
140 // Secondaries are created at the current track coordinates
141 G4Track* sec = new G4Track(new G4DynamicParticle(thePhonon, vgroup, energy),
142 currentTrack->GetGlobalTime(),
143 currentTrack->GetPosition());
144
145 // Store wavevector in lookup table for future tracking
146 trackKmap->SetK(sec, theLattice->RotateToGlobal(waveVec));
147
148 if (verboseLevel>1) {
149 G4cout << GetProcessName() << " secondary K rotated to "
150 << trackKmap->GetK(sec) << G4endl;
151 }
152
153 sec->SetVelocity(theLattice->MapKtoV(polarization, waveVec));
154 sec->UseGivenVelocity(true);
155
156 return sec;
157 }
158