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26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class header file
30 //
31 //
32 // File name: G4eBremsstrahlungRelModel
33 // extention of standard G4eBremsstrahlungModel
34 //
35 // Author: Andreas Schaelicke
36 //
37 // Creation date: 28.03.2008
38 //
39 // Modifications:
40 //
41 // 15.07.18 introduced data structures to store LPM functions and element depen
42 // dent data for faster run-time computation (see more in .cc M.Novak)
43 //
44 // Class Description:
45 //
46 // Implementation of energy loss for gamma emission by electrons and
47 // positrons including an improved version of the LPM effect
48
49 // -------------------------------------------------------------------
50 //
51
52 #ifndef G4eBremsstrahlungRelModel_h
53 #define G4eBremsstrahlungRelModel_h 1
54
55 #include "G4VEmModel.hh"
56 #include <memory>
57
58 class G4ParticleChangeForLoss;
59
60 class G4eBremsstrahlungRelModel : public G4VEmModel {
61
62 public:
63
64 explicit G4eBremsstrahlungRelModel(const G4ParticleDefinition* p=nullptr,
65 const G4String& nam="eBremLPM");
66
67 ~G4eBremsstrahlungRelModel() override;
68
69 void Initialise(const G4ParticleDefinition*, const G4DataVector&) override;
70
71 void InitialiseLocal(const G4ParticleDefinition*,
72 G4VEmModel* masterModel) override;
73
74 G4double ComputeDEDXPerVolume(const G4Material*,
75 const G4ParticleDefinition*,
76 G4double ekin,
77 G4double cutEnergy) override;
78
79 G4double ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
80 G4double ekin,
81 G4double zet,
82 G4double,
83 G4double cutEnergy,
84 G4double maxEnergy = DBL_MAX) override;
85
86 void SampleSecondaries(std::vector<G4DynamicParticle*>*,
87 const G4MaterialCutsCouple*,
88 const G4DynamicParticle*,
89 G4double cutEnergy,
90 G4double maxEnergy) override;
91
92 void SetupForMaterial(const G4ParticleDefinition*,
93 const G4Material*, G4double) override;
94
95 G4double MinPrimaryEnergy(const G4Material*,
96 const G4ParticleDefinition*,
97 G4double cutEnergy) override;
98
99 protected:
100
101 virtual G4double ComputeDXSectionPerAtom(G4double gammaEnergy);
102
103 void SetParticle(const G4ParticleDefinition* p);
104
105 private:
106
107 G4double ComputeBremLoss(G4double cutEnergy);
108
109 G4double ComputeXSectionPerAtom(G4double cutEnergy);
110
111 G4double ComputeRelDXSectionPerAtom(G4double gammaEnergy);
112
113 // init special data per element i.e. per Z
114 void InitialiseElementData();
115
116 // methods for initialisation and run-time evaluation of LPM functions:
117 void InitLPMFunctions();
118
119 void ComputeLPMfunctions(G4double& funcXiS,
120 G4double& funcGS,
121 G4double& funcPhiS,
122 const G4double egamma);
123
124 void GetLPMFunctions(G4double& lpmGs,
125 G4double& lpmPhis,
126 const G4double ss);
127
128 void ComputeLPMGsPhis(G4double& funcGS,
129 G4double& funcPhiS,
130 const G4double varShat);
131
132 // for evaluating screening related functions
133 void ComputeScreeningFunctions(G4double& phi1,
134 G4double& phi1m2,
135 G4double& psi1,
136 G4double& psi1m2,
137 const G4double gam,
138 const G4double eps);
139 // hide assignment operator and cctr
140 G4eBremsstrahlungRelModel& operator=
141 (const G4eBremsstrahlungRelModel& right) = delete;
142 G4eBremsstrahlungRelModel(const G4eBremsstrahlungRelModel&) = delete;
143
144 private:
145
146 G4bool fIsUseCompleteScreening = false;
147 G4bool fIsInitializer = false;
148 G4bool fUseLPM = true;
149
150 protected:
151
152 G4bool fIsElectron = true;
153 G4bool fIsScatOffElectron = false;
154 G4bool fIsLPMActive = false;
155 //
156 G4int fCurrentIZ = 0;
157 const G4ParticleDefinition* fPrimaryParticle = nullptr;
158 G4ParticleDefinition* fGammaParticle = nullptr;
159 G4ParticleChangeForLoss* fParticleChange = nullptr;
160 // cash
161 G4double fPrimaryParticleMass = 0.;
162 G4double fPrimaryKinEnergy = 0.;
163 G4double fPrimaryTotalEnergy = 0.;
164 G4double fDensityFactor = 0.;
165 G4double fDensityCorr = 0.;
166 G4double fLowestKinEnergy;
167 // scattering off electrons
168 G4double fNucTerm = 0.;
169 G4double fSumTerm = 0.;
170
171 private:
172
173 // LPM related members
174 G4double fLPMEnergyThreshold;
175 G4double fLPMEnergy;
176
177 protected:
178
179 static const G4double gBremFactor;
180 static const G4double gMigdalConstant;
181
182 private:
183
184 static const G4int gMaxZet;
185 //
186 static const G4double gLPMconstant;
187 //
188 static const G4double gXGL[8];
189 static const G4double gWGL[8];
190 static const G4double gFelLowZet[8];
191 static const G4double gFinelLowZet[8];
192 //
193 struct ElementData {
194 /** @brief \f$ \ln(Z) \f$ */
195 G4double fLogZ;
196 /** @brief \f$ \ln(Z)/3 + f_c \f$ */
197 G4double fFz;
198 /** @brief \f$ ((Fel-fc)+Finel*invZ)\f$ */
199 G4double fZFactor1;
200 /** @brief \f$ (Fel-fc)\f$ */
201 G4double fZFactor11;
202 /** @brief \f$ (1.0+invZ)/12 \f$ */
203 G4double fZFactor2;
204 // LPM variables
205 G4double fVarS1;
206 G4double fILVarS1;
207 G4double fILVarS1Cond;
208 // constant factors to the screening function evaluations
209 G4double fGammaFactor;
210 G4double fEpsilonFactor;
211 };
212 //
213 struct LPMFuncs {
214 LPMFuncs() : fIsInitialized(false), fISDelta(100.), fSLimit(2.) {}
215 G4bool fIsInitialized;
216 G4double fISDelta;
217 G4double fSLimit;
218 std::vector<G4double> fLPMFuncG;
219 std::vector<G4double> fLPMFuncPhi;
220 };
221 //
222 static std::shared_ptr<LPMFuncs> gLPMFuncs();
223 static std::shared_ptr<std::vector<ElementData*>> gElementData();
224 std::shared_ptr<LPMFuncs> fLPMFuncs;
225 std::shared_ptr<std::vector<ElementData*>> fElementData;
226 };
227
228 #endif
229