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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4hBetheBlochModel
33 //
34 // Author: V.Ivanchenko (Vladimir.Ivanchenko@cern.ch)
35 //
36 // Creation date: 20 July 2000
37 //
38 // Modifications:
39 // 20/07/2000 V.Ivanchenko First implementation
40 // 03/10/2000 V.Ivanchenko clean up accoding to CodeWizard
41 //
42 // Class Description:
43 //
44 // Bethe-Bloch ionisation model
45 //
46 // Class Description: End
47 //
48 // -------------------------------------------------------------------
49 //
50 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
51
52 #include "G4hBetheBlochModel.hh"
53
54 #include "globals.hh"
55 #include "G4PhysicalConstants.hh"
56 #include "G4SystemOfUnits.hh"
57 #include "G4DynamicParticle.hh"
58 #include "G4ParticleDefinition.hh"
59 #include "G4Material.hh"
60
61 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
62
63 G4hBetheBlochModel::G4hBetheBlochModel(const G4String& name)
64 : G4VLowEnergyModel(name),
65 twoln10(2.*std::log(10.)),
66 bg2lim(0.0169),
67 taulim(8.4146e-3),
68 lowEnergyLimit(1.*MeV),
69 highEnergyLimit(100.*GeV)
70 {;}
71
72 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
73
74 G4hBetheBlochModel::~G4hBetheBlochModel()
75 {;}
76
77 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
78
79 G4double G4hBetheBlochModel::TheValue(const G4DynamicParticle* particle,
80 const G4Material* material)
81 {
82 G4double energy = particle->GetKineticEnergy() ;
83 G4double particleMass = particle->GetMass() ;
84
85 G4double eloss = BetheBlochFormula(material,energy,particleMass) ;
86
87 return eloss ;
88 }
89
90 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
91
92 G4double G4hBetheBlochModel::TheValue(const G4ParticleDefinition* aParticle,
93 const G4Material* material,
94 G4double kineticEnergy)
95 {
96 G4double particleMass = aParticle->GetPDGMass() ;
97 G4double eloss = BetheBlochFormula(material,kineticEnergy,particleMass) ;
98
99 return eloss ;
100 }
101
102 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
103
104 G4double G4hBetheBlochModel::HighEnergyLimit(
105 const G4ParticleDefinition* ,
106 const G4Material* ) const
107 {
108 return highEnergyLimit ;
109 }
110
111 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
112
113 G4double G4hBetheBlochModel::LowEnergyLimit(
114 const G4ParticleDefinition* aParticle,
115 const G4Material* material) const
116 {
117 G4double taul = (material->GetIonisation()->GetTaul())*
118 (aParticle->GetPDGMass()) ;
119 return taul ;
120 }
121
122 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
123
124 G4double G4hBetheBlochModel::HighEnergyLimit(
125 const G4ParticleDefinition* ) const
126 {
127 return highEnergyLimit ;
128 }
129
130 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
131
132 G4double G4hBetheBlochModel::LowEnergyLimit(
133 const G4ParticleDefinition* ) const
134 {
135 return lowEnergyLimit ;
136 }
137
138 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
139
140 G4bool G4hBetheBlochModel::IsInCharge(const G4DynamicParticle* ,
141 const G4Material* ) const
142 {
143 return true ;
144 }
145
146 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
147
148 G4bool G4hBetheBlochModel::IsInCharge(const G4ParticleDefinition* ,
149 const G4Material* ) const
150 {
151 return true ;
152 }
153
154 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
155
156 G4double G4hBetheBlochModel::BetheBlochFormula(
157 const G4Material* material,
158 G4double kineticEnergy,
159 G4double particleMass) const
160 {
161 // This member function is applied normally to proton/antiproton
162 G4double ionloss ;
163
164 G4double rateMass = electron_mass_c2/particleMass ;
165
166 G4double taul = material->GetIonisation()->GetTaul() ;
167 G4double tau = kineticEnergy/particleMass ; // tau is relative energy
168
169 // It is not normal case for this function
170 // for low energy parametrisation have to be applied
171 if ( tau < taul ) tau = taul ;
172
173 // some local variables
174
175 G4double gamma,bg2,beta2,tmax,x,delta,sh ;
176 G4double electronDensity = material->GetElectronDensity();
177 G4double eexc = material->GetIonisation()->GetMeanExcitationEnergy();
178 G4double eexc2 = eexc*eexc ;
179 G4double cden = material->GetIonisation()->GetCdensity();
180 G4double mden = material->GetIonisation()->GetMdensity();
181 G4double aden = material->GetIonisation()->GetAdensity();
182 G4double x0den = material->GetIonisation()->GetX0density();
183 G4double x1den = material->GetIonisation()->GetX1density();
184 G4double* shellCorrectionVector =
185 material->GetIonisation()->GetShellCorrectionVector();
186
187 gamma = tau + 1.0 ;
188 bg2 = tau*(tau+2.0) ;
189 beta2 = bg2/(gamma*gamma) ;
190 tmax = 2.*electron_mass_c2*bg2/(1.+2.*gamma*rateMass+rateMass*rateMass) ;
191
192 ionloss = std::log(2.0*electron_mass_c2*bg2*tmax/eexc2)-2.0*beta2 ;
193
194 // density correction
195 x = std::log(bg2)/twoln10 ;
196 if ( x < x0den ) {
197 delta = 0.0 ;
198
199 } else {
200 delta = twoln10*x - cden ;
201 if ( x < x1den ) delta += aden*std::pow((x1den-x),mden) ;
202 }
203
204 // shell correction
205 sh = 0.0 ;
206 x = 1.0 ;
207
208 if ( bg2 > bg2lim ) {
209 for (G4int k=0; k<=2; k++) {
210 x *= bg2 ;
211 sh += shellCorrectionVector[k]/x;
212 }
213
214 } else {
215 for (G4int k=0; k<=2; k++) {
216 x *= bg2lim ;
217 sh += shellCorrectionVector[k]/x;
218 }
219 sh *= std::log(tau/taul)/std::log(taulim/taul) ;
220 }
221
222 // now compute the total ionization loss
223
224 ionloss -= delta + sh ;
225 ionloss *= twopi_mc2_rcl2*electronDensity/beta2 ;
226
227 if ( ionloss < 0.0) ionloss = 0.0 ;
228
229 return ionloss;
230 }
231
232
233