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26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4LowEWentzelVIModel
33 //
34 // Author: V.Ivanchenko
35 //
36 // Creation date: 11.02.2014 from G4WentzelVIModel
37 //
38 // Modifications:
39 //
40 // Class Description:
41 //
42
43 // -------------------------------------------------------------------
44 //
45
46 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
47 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
48
49 #include "G4LowEWentzelVIModel.hh"
50 #include "G4PhysicalConstants.hh"
51 #include "G4SystemOfUnits.hh"
52
53 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
54
55 G4LowEWentzelVIModel::G4LowEWentzelVIModel() :
56 G4WentzelVIModel(true, "LowEnWentzelVI")
57 {
58 SetSingleScatteringFactor(0.5);
59 }
60
61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
62
63 G4double G4LowEWentzelVIModel::ComputeTruePathLengthLimit(
64 const G4Track& track,
65 G4double& currentMinimalStep)
66 {
67 G4double tlimit = currentMinimalStep;
68 const G4DynamicParticle* dp = track.GetDynamicParticle();
69 G4StepPoint* sp = track.GetStep()->GetPreStepPoint();
70 G4StepStatus stepStatus = sp->GetStepStatus();
71 singleScatteringMode = false;
72
73 // initialisation for each step, lambda may be computed from scratch
74 preKinEnergy = dp->GetKineticEnergy();
75 DefineMaterial(track.GetMaterialCutsCouple());
76 lambdaeff = GetTransportMeanFreePath(particle,preKinEnergy);
77 currentRange = GetRange(particle,preKinEnergy,currentCouple);
78 cosTetMaxNuc = wokvi->SetupKinematic(preKinEnergy, currentMaterial);
79
80 // extra check for abnormal situation
81 // this check needed to run MSC with eIoni and eBrem inactivated
82 tlimit = std::min(tlimit, currentRange);
83
84 // stop here if small range particle
85 if(tlimit < tlimitminfix) {
86 return ConvertTrueToGeom(tlimit, currentMinimalStep);
87 }
88
89 // pre step
90 G4double presafety = sp->GetSafety();
91 // far from geometry boundary
92 if(currentRange < presafety) {
93 return ConvertTrueToGeom(tlimit, currentMinimalStep);
94 }
95
96 // compute presafety again if presafety <= 0 and no boundary
97 // i.e. when it is needed for optimization purposes
98 if(stepStatus != fGeomBoundary && presafety < tlimitminfix) {
99 presafety = ComputeSafety(sp->GetPosition(), tlimit);
100 if(currentRange < presafety) {
101 return ConvertTrueToGeom(tlimit, currentMinimalStep);
102 }
103 }
104 /*
105 G4cout << "e(MeV)= " << preKinEnergy/MeV
106 << " " << particle->GetParticleName()
107 << " CurLimit(mm)= " << tlimit/mm <<" safety(mm)= " << presafety/mm
108 << " R(mm)= " <<currentRange/mm
109 << " L0(mm^-1)= " << lambdaeff*mm
110 <<G4endl;
111 */
112 // natural limit for high energy
113 G4double rlimit = std::max(facrange*currentRange, lambdaeff);
114
115 // low-energy e-
116 rlimit = std::max(rlimit, facsafety*presafety);
117
118 tlimit = std::min(tlimit, rlimit);
119 tlimit = std::max(tlimit, tlimitminfix);
120
121 // step limit in infinite media
122 tlimit = std::min(tlimit, 50*currentMaterial->GetRadlen()/facgeom);
123
124 //compute geomlimit and force few steps within a volume
125 if (steppingAlgorithm == fUseDistanceToBoundary
126 && stepStatus == fGeomBoundary) {
127
128 G4double geomlimit = ComputeGeomLimit(track, presafety, currentRange);
129 tlimit = std::min(tlimit, geomlimit/facgeom);
130 }
131 /*
132 G4cout << particle->GetParticleName() << " E(MeV)= " << preKinEnergy
133 << " L0= " << lambdaeff << " R= " << currentRange
134 << " tlimit= " << tlimit
135 << " currentMinimalStep= " << currentMinimalStep << G4endl;
136 */
137 return ConvertTrueToGeom(tlimit, currentMinimalStep);
138 }
139
140 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
141