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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4DynamicParticleMSC
33 //
34 // Author: Vladimir Ivanchenko
35 //
36 // Creation date: 17.08.2024
37 //
38 // -------------------------------------------------------------------
39 //
40 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
41 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
42
43 #include "G4DynamicParticleMSC.hh"
44 #include "G4PhysicalConstants.hh"
45 #include "G4SystemOfUnits.hh"
46 #include "G4EmProcessSubType.hh"
47 #include "G4LossTableManager.hh"
48 #include "G4Step.hh"
49 #include "G4Track.hh"
50 #include "G4Log.hh"
51 #include "G4Exp.hh"
52
53 namespace
54 {
55 constexpr G4double c_highland = 13.6*CLHEP::MeV;
56 }
57
58 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
59
60 G4DynamicParticleMSC::G4DynamicParticleMSC()
61 : G4VContinuousDiscreteProcess("dynPartMSC")
62 {
63 SetVerboseLevel(1);
64 SetProcessSubType(fDynamicMultipleScattering);
65 lManager = G4LossTableManager::Instance();
66 lManager->Register(this);
67 }
68
69 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
70
71 G4DynamicParticleMSC::~G4DynamicParticleMSC()
72 {
73 lManager->DeRegister(this);
74 }
75
76 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
77
78 void G4DynamicParticleMSC::PreStepInitialisation(const G4Track& track)
79 {
80 fMaterial = track.GetMaterial();
81 fZeff = fMaterial->GetIonisation()->GetZeffective();
82 auto dpart = track.GetDynamicParticle();
83 fEkinPreStep = dpart->GetKineticEnergy();
84 fBeta = dpart->GetBeta();
85 fCharge = dpart->GetCharge()/CLHEP::eplus;
86 fMass = std::max(dpart->GetMass(), CLHEP::electron_mass_c2);
87 }
88
89 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
90
91 G4double G4DynamicParticleMSC::AlongStepGetPhysicalInteractionLength(
92 const G4Track& track, G4double, G4double, G4double&,
93 G4GPILSelection* selection)
94 {
95 *selection = CandidateForSelection;
96 PreStepInitialisation(track);
97
98 // no step limit for the time being
99 return DBL_MAX;
100 }
101
102 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
103
104 G4double G4DynamicParticleMSC::PostStepGetPhysicalInteractionLength(
105 const G4Track&, G4double,
106 G4ForceCondition* condition)
107 {
108 *condition = NotForced;
109 return DBL_MAX;
110 }
111
112 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
113
114 G4VParticleChange* G4DynamicParticleMSC::AlongStepDoIt(const G4Track& track,
115 const G4Step& step)
116 {
117 fParticleChange.InitialiseMSC(track, step);
118
119 // no energy loss
120 if (fCharge == 0.0) { return &fParticleChange; }
121
122 G4double geomLength = step.GetStepLength();
123 G4double y = geomLength/fMaterial->GetRadlen();
124 G4double theta0 = c_highland*std::abs(fCharge)*std::sqrt(y)*
125 (1.0 + 0.038*G4Log(y*fCharge*fCharge/(fBeta*fBeta)))/fBeta;
126
127 if (theta0 < 0.001) { return &fParticleChange; }
128 G4double cost = 1.0;
129 G4double r = G4UniformRand();
130 if (theta0 < 1.0) {
131 G4double theta2 = theta0*theta0;
132 cost -= theta2*G4Log(1.0 + r*(G4Exp(2.0/theta2) - 1.0));
133 } else {
134 cost -= 2.0*r;
135 }
136 G4double phi = CLHEP::twopi*G4UniformRand();
137 G4double sint = std::sqrt((1.0 - cost)*(1.0 + cost));
138 fNewDir.set(sint*std::cos(phi), sint*std::sin(phi), cost);
139 fNewDir.rotateUz(step.GetPostStepPoint()->GetMomentumDirection());
140
141 fParticleChange.ProposeMomentumDirection(fNewDir);
142 fParticleChange.ProposeTrueStepLength(geomLength);
143 return &fParticleChange;
144 }
145
146 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
147
148 G4double G4DynamicParticleMSC::GetMeanFreePath(const G4Track&, G4double,
149 G4ForceCondition* condition)
150 {
151 *condition = Forced;
152 return DBL_MAX;
153 }
154
155 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
156
157 G4double G4DynamicParticleMSC::GetContinuousStepLimit(const G4Track& track,
158 G4double previousStepSize,
159 G4double currentMinimalStep,
160 G4double& currentSafety)
161 {
162 G4GPILSelection selection = NotCandidateForSelection;
163 G4double x = AlongStepGetPhysicalInteractionLength(track, previousStepSize,
164 currentMinimalStep,
165 currentSafety, &selection);
166 return x;
167 }
168
169 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
170
171 void G4DynamicParticleMSC::ProcessDescription(std::ostream& out) const
172 {
173 out << "G4DynamicParticleMSC: no delta rays" << G4endl;
174 }
175
176 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
177