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25 //
26 // G4TransitionRadiation class -- implementation file
27
28 // GEANT 4 class implementation file --- Copyright CERN 1995
29
30 // For information related to this code, please, contact
31 // CERN, CN Division, ASD Group
32 // History:
33 // 1st version 11.09.97 V. Grichine (Vladimir.Grichine@cern.ch )
34 // 2nd version 16.12.97 V. Grichine
35 // 3rd version 28.07.05, P.Gumplinger add G4ProcessType to constructor
36
37 //#include <cmath>
38
39 #include "G4TransitionRadiation.hh"
40
41 #include "G4EmProcessSubType.hh"
42
43 ///////////////////////////////////////////////////////////////////////
44 // Constructor for selected couple of materials
45 G4TransitionRadiation::G4TransitionRadiation(const G4String& processName,
46 G4ProcessType type)
47 : G4VDiscreteProcess(processName, type)
48 {
49 SetProcessSubType(fTransitionRadiation);
50 fMatIndex1 = fMatIndex2 = 0;
51
52 fGamma = fEnergy = fVarAngle = fMinEnergy = fMaxEnergy = fMaxTheta = 0.0;
53 fSigma1 = fSigma2 = 0.0;
54 }
55
56 //////////////////////////////////////////////////////////////////////
57 // Destructor
58 G4TransitionRadiation::~G4TransitionRadiation() = default;
59
60 void G4TransitionRadiation::ProcessDescription(std::ostream& out) const
61 {
62 out << "Base class for simulation of x-ray transition radiation.\n";
63 }
64
65 G4bool G4TransitionRadiation::IsApplicable(
66 const G4ParticleDefinition& aParticleType)
67 {
68 return (aParticleType.GetPDGCharge() != 0.0);
69 }
70
71 G4double G4TransitionRadiation::GetMeanFreePath(const G4Track&, G4double,
72 G4ForceCondition* condition)
73 {
74 *condition = Forced;
75 return DBL_MAX; // so TR doesn't limit mean free path
76 }
77
78 G4VParticleChange* G4TransitionRadiation::PostStepDoIt(const G4Track&,
79 const G4Step&)
80 {
81 ClearNumberOfInteractionLengthLeft();
82 return &aParticleChange;
83 }
84
85 ///////////////////////////////////////////////////////////////////
86 // Sympson integral of TR spectral-angle density over energy between
87 // the limits energy 1 and energy2 at fixed varAngle = 1 - std::cos(Theta)
88 G4double G4TransitionRadiation::IntegralOverEnergy(G4double energy1,
89 G4double energy2,
90 G4double varAngle) const
91 {
92 G4int i;
93 G4double h, sumEven = 0.0, sumOdd = 0.0;
94 h = 0.5 * (energy2 - energy1) / fSympsonNumber;
95 for(i = 1; i < fSympsonNumber; i++)
96 {
97 sumEven += SpectralAngleTRdensity(energy1 + 2 * i * h, varAngle);
98 sumOdd += SpectralAngleTRdensity(energy1 + (2 * i - 1) * h, varAngle);
99 }
100 sumOdd +=
101 SpectralAngleTRdensity(energy1 + (2 * fSympsonNumber - 1) * h, varAngle);
102 return h *
103 (SpectralAngleTRdensity(energy1, varAngle) +
104 SpectralAngleTRdensity(energy2, varAngle) + 4.0 * sumOdd +
105 2.0 * sumEven) /
106 3.0;
107 }
108
109 ///////////////////////////////////////////////////////////////////
110 // Sympson integral of TR spectral-angle density over energy between
111 // the limits varAngle1 and varAngle2 at fixed energy
112 G4double G4TransitionRadiation::IntegralOverAngle(G4double energy,
113 G4double varAngle1,
114 G4double varAngle2) const
115 {
116 G4int i;
117 G4double h, sumEven = 0.0, sumOdd = 0.0;
118 h = 0.5 * (varAngle2 - varAngle1) / fSympsonNumber;
119 for(i = 1; i < fSympsonNumber; ++i)
120 {
121 sumEven += SpectralAngleTRdensity(energy, varAngle1 + 2 * i * h);
122 sumOdd += SpectralAngleTRdensity(energy, varAngle1 + (2 * i - 1) * h);
123 }
124 sumOdd +=
125 SpectralAngleTRdensity(energy, varAngle1 + (2 * fSympsonNumber - 1) * h);
126
127 return h *
128 (SpectralAngleTRdensity(energy, varAngle1) +
129 SpectralAngleTRdensity(energy, varAngle2) + 4.0 * sumOdd +
130 2.0 * sumEven) /
131 3.0;
132 }
133
134 ///////////////////////////////////////////////////////////////////
135 // The number of transition radiation photons generated in the
136 // angle interval between varAngle1 and varAngle2
137 G4double G4TransitionRadiation::AngleIntegralDistribution(
138 G4double varAngle1, G4double varAngle2) const
139 {
140 G4int i;
141 G4double h, sumEven = 0.0, sumOdd = 0.0;
142 h = 0.5 * (varAngle2 - varAngle1) / fSympsonNumber;
143 for(i = 1; i < fSympsonNumber; ++i)
144 {
145 sumEven += IntegralOverEnergy(fMinEnergy,
146 fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
147 varAngle1 + 2 * i * h) +
148 IntegralOverEnergy(fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
149 fMaxEnergy, varAngle1 + 2 * i * h);
150 sumOdd += IntegralOverEnergy(fMinEnergy,
151 fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
152 varAngle1 + (2 * i - 1) * h) +
153 IntegralOverEnergy(fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
154 fMaxEnergy, varAngle1 + (2 * i - 1) * h);
155 }
156 sumOdd +=
157 IntegralOverEnergy(fMinEnergy, fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
158 varAngle1 + (2 * fSympsonNumber - 1) * h) +
159 IntegralOverEnergy(fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy), fMaxEnergy,
160 varAngle1 + (2 * fSympsonNumber - 1) * h);
161
162 return h *
163 (IntegralOverEnergy(fMinEnergy,
164 fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
165 varAngle1) +
166 IntegralOverEnergy(fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
167 fMaxEnergy, varAngle1) +
168 IntegralOverEnergy(fMinEnergy,
169 fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
170 varAngle2) +
171 IntegralOverEnergy(fMinEnergy + 0.3 * (fMaxEnergy - fMinEnergy),
172 fMaxEnergy, varAngle2) +
173 4.0 * sumOdd + 2.0 * sumEven) /
174 3.0;
175 }
176
177 ///////////////////////////////////////////////////////////////////
178 // The number of transition radiation photons, generated in the
179 // energy interval between energy1 and energy2
180 G4double G4TransitionRadiation::EnergyIntegralDistribution(
181 G4double energy1, G4double energy2) const
182 {
183 G4int i;
184 G4double h, sumEven = 0.0, sumOdd = 0.0;
185 h = 0.5 * (energy2 - energy1) / fSympsonNumber;
186 for(i = 1; i < fSympsonNumber; ++i)
187 {
188 sumEven +=
189 IntegralOverAngle(energy1 + 2 * i * h, 0.0, 0.01 * fMaxTheta) +
190 IntegralOverAngle(energy1 + 2 * i * h, 0.01 * fMaxTheta, fMaxTheta);
191 sumOdd +=
192 IntegralOverAngle(energy1 + (2 * i - 1) * h, 0.0, 0.01 * fMaxTheta) +
193 IntegralOverAngle(energy1 + (2 * i - 1) * h, 0.01 * fMaxTheta, fMaxTheta);
194 }
195 sumOdd += IntegralOverAngle(energy1 + (2 * fSympsonNumber - 1) * h, 0.0,
196 0.01 * fMaxTheta) +
197 IntegralOverAngle(energy1 + (2 * fSympsonNumber - 1) * h,
198 0.01 * fMaxTheta, fMaxTheta);
199
200 return h *
201 (IntegralOverAngle(energy1, 0.0, 0.01 * fMaxTheta) +
202 IntegralOverAngle(energy1, 0.01 * fMaxTheta, fMaxTheta) +
203 IntegralOverAngle(energy2, 0.0, 0.01 * fMaxTheta) +
204 IntegralOverAngle(energy2, 0.01 * fMaxTheta, fMaxTheta) +
205 4.0 * sumOdd + 2.0 * sumEven) /
206 3.0;
207 }
208