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G4TransitionRadiation.cc
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26 //
27 // G4TransitionRadiation class -- implementation file
28 
29 // GEANT 4 class implementation file --- Copyright CERN 1995
30 // CERN Geneva Switzerland
31 
32 // For information related to this code, please, contact
33 // CERN, CN Division, ASD Group
34 // History:
35 // 1st version 11.09.97 V. Grichine (Vladimir.Grichine@cern.ch )
36 // 2nd version 16.12.97 V. Grichine
37 // 3rd version 28.07.05, P.Gumplinger add G4ProcessType to constructor
38 
39 
40 #include <cmath>
41 
42 #include "G4TransitionRadiation.hh"
43 #include "G4Material.hh"
44 #include "G4EmProcessSubType.hh"
45 
46 // Local constants
47 
48 const G4int G4TransitionRadiation::fSympsonNumber = 100 ;
49 const G4int G4TransitionRadiation::fGammaNumber = 15 ;
50 const G4int G4TransitionRadiation::fPointNumber = 100 ;
51 
52 
54 //
55 // Constructor for selected couple of materials
56 //
57 
58 G4TransitionRadiation::
59 G4TransitionRadiation( const G4String& processName, G4ProcessType type )
60  : G4VDiscreteProcess(processName, type)
61 {
62  SetProcessSubType(fTransitionRadiation);
63  fMatIndex1 = fMatIndex2 = 0;
64 
65  fGamma = fEnergy = fVarAngle = fMinEnergy = fMaxEnergy = fMaxTheta = fSigma1 = fSigma2 = 0.0;
66 }
67 
69 //
70 // Destructor
71 //
72 
73 G4TransitionRadiation::~G4TransitionRadiation()
74 {}
75 
76 G4bool
77 G4TransitionRadiation::IsApplicable(const G4ParticleDefinition& aParticleType)
78 {
79  return ( aParticleType.GetPDGCharge() != 0.0 );
80 }
81 
82 G4double G4TransitionRadiation::GetMeanFreePath(const G4Track&,
83  G4double,
84  G4ForceCondition* condition)
85 {
86  *condition = Forced;
87  return DBL_MAX; // so TR doesn't limit mean free path
88 }
89 
90 G4VParticleChange* G4TransitionRadiation::PostStepDoIt(const G4Track&,
91  const G4Step&)
92 {
93  ClearNumberOfInteractionLengthLeft();
94  return &aParticleChange;
95 }
96 
98 //
99 // Sympson integral of TR spectral-angle density over energy between
100 // the limits energy 1 and energy2 at fixed varAngle = 1 - std::cos(Theta)
101 
102 G4double
103 G4TransitionRadiation::IntegralOverEnergy( G4double energy1,
104  G4double energy2,
105  G4double varAngle ) const
106 {
107  G4int i ;
108  G4double h , sumEven = 0.0 , sumOdd = 0.0 ;
109  h = 0.5*(energy2 - energy1)/fSympsonNumber ;
110  for(i=1;i<fSympsonNumber;i++)
111  {
112  sumEven += SpectralAngleTRdensity(energy1 + 2*i*h,varAngle) ;
113  sumOdd += SpectralAngleTRdensity(energy1 + (2*i - 1)*h,varAngle) ;
114  }
115  sumOdd += SpectralAngleTRdensity(energy1 + (2*fSympsonNumber - 1)*h,varAngle) ;
116  return h*( SpectralAngleTRdensity(energy1,varAngle)
117  + SpectralAngleTRdensity(energy2,varAngle)
118  + 4.0*sumOdd + 2.0*sumEven )/3.0 ;
119 }
120 
121 
122 
124 //
125 // Sympson integral of TR spectral-angle density over energy between
126 // the limits varAngle1 and varAngle2 at fixed energy
127 
128 G4double
129 G4TransitionRadiation::IntegralOverAngle( G4double energy,
130  G4double varAngle1,
131  G4double varAngle2 ) const
132 {
133  G4int i ;
134  G4double h , sumEven = 0.0 , sumOdd = 0.0 ;
135  h = 0.5*(varAngle2 - varAngle1)/fSympsonNumber ;
136  for(i=1;i<fSympsonNumber;i++)
137  {
138  sumEven += SpectralAngleTRdensity(energy,varAngle1 + 2*i*h) ;
139  sumOdd += SpectralAngleTRdensity(energy,varAngle1 + (2*i - 1)*h) ;
140  }
141  sumOdd += SpectralAngleTRdensity(energy,varAngle1 + (2*fSympsonNumber - 1)*h) ;
142 
143  return h*( SpectralAngleTRdensity(energy,varAngle1)
144  + SpectralAngleTRdensity(energy,varAngle2)
145  + 4.0*sumOdd + 2.0*sumEven )/3.0 ;
146 }
147 
149 //
150 // The number of transition radiation photons generated in the
151 // angle interval between varAngle1 and varAngle2
152 //
153 
154 G4double G4TransitionRadiation::
155 AngleIntegralDistribution( G4double varAngle1,
156  G4double varAngle2 ) const
157 {
158  G4int i ;
159  G4double h , sumEven = 0.0 , sumOdd = 0.0 ;
160  h = 0.5*(varAngle2 - varAngle1)/fSympsonNumber ;
161  for(i=1;i<fSympsonNumber;i++)
162  {
163  sumEven += IntegralOverEnergy(fMinEnergy,
164  fMinEnergy +0.3*(fMaxEnergy-fMinEnergy),
165  varAngle1 + 2*i*h)
166  + IntegralOverEnergy(fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
167  fMaxEnergy,
168  varAngle1 + 2*i*h);
169  sumOdd += IntegralOverEnergy(fMinEnergy,
170  fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
171  varAngle1 + (2*i - 1)*h)
172  + IntegralOverEnergy(fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
173  fMaxEnergy,
174  varAngle1 + (2*i - 1)*h) ;
175  }
176  sumOdd += IntegralOverEnergy(fMinEnergy,
177  fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
178  varAngle1 + (2*fSympsonNumber - 1)*h)
179  + IntegralOverEnergy(fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
180  fMaxEnergy,
181  varAngle1 + (2*fSympsonNumber - 1)*h) ;
182 
183  return h*(IntegralOverEnergy(fMinEnergy,
184  fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
185  varAngle1)
186  + IntegralOverEnergy(fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
187  fMaxEnergy,
188  varAngle1)
189  + IntegralOverEnergy(fMinEnergy,
190  fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
191  varAngle2)
192  + IntegralOverEnergy(fMinEnergy + 0.3*(fMaxEnergy - fMinEnergy),
193  fMaxEnergy,
194  varAngle2)
195  + 4.0*sumOdd + 2.0*sumEven )/3.0 ;
196 }
197 
199 //
200 // The number of transition radiation photons, generated in the
201 // energy interval between energy1 and energy2
202 //
203 
204 G4double G4TransitionRadiation::
205 EnergyIntegralDistribution( G4double energy1,
206  G4double energy2 ) const
207 {
208  G4int i ;
209  G4double h , sumEven = 0.0 , sumOdd = 0.0 ;
210  h = 0.5*(energy2 - energy1)/fSympsonNumber ;
211  for(i=1;i<fSympsonNumber;i++)
212  {
213  sumEven += IntegralOverAngle(energy1 + 2*i*h,0.0,0.01*fMaxTheta )
214  + IntegralOverAngle(energy1 + 2*i*h,0.01*fMaxTheta,fMaxTheta);
215  sumOdd += IntegralOverAngle(energy1 + (2*i - 1)*h,0.0,0.01*fMaxTheta)
216  + IntegralOverAngle(energy1 + (2*i - 1)*h,0.01*fMaxTheta,fMaxTheta) ;
217  }
218  sumOdd += IntegralOverAngle(energy1 + (2*fSympsonNumber - 1)*h,
219  0.0,0.01*fMaxTheta)
220  + IntegralOverAngle(energy1 + (2*fSympsonNumber - 1)*h,
221  0.01*fMaxTheta,fMaxTheta) ;
222 
223  return h*(IntegralOverAngle(energy1,0.0,0.01*fMaxTheta)
224  + IntegralOverAngle(energy1,0.01*fMaxTheta,fMaxTheta)
225  + IntegralOverAngle(energy2,0.0,0.01*fMaxTheta)
226  + IntegralOverAngle(energy2,0.01*fMaxTheta,fMaxTheta)
227  + 4.0*sumOdd + 2.0*sumEven )/3.0 ;
228 }
229 
230 // end of G4TransitionRadiation implementation file --------------------------