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25 //
26 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4IonYangFluctuationModel
33 //
34 // Author: V.Ivanchenko (Vladimir.Ivanchenko@cern.ch)
35 //
36 // Creation date: 18 August 2000
37 //
38 // Modifications:
39 // 18/08/2000 V.Ivanchenko First implementation
40 // 04/09/2000 V.Ivanchenko Rename fluctuations
41 // 03/10/2000 V.Ivanchenko CodeWizard clean up
42 // 10/05/2001 V.Ivanchenko Clean up againist Linux compilation with -Wall
43 //
44 // -------------------------------------------------------------------
45 // Class Description:
46 //
47 // The aproximation of additional ion energy loss fluctuations
48 // Q.Yang et al., NIM B61(1991)149-155.
49 //
50 // Class Description: End
51 //
52 // -------------------------------------------------------------------
53 //
54 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
55
56 #include "G4IonYangFluctuationModel.hh"
57
58 #include "globals.hh"
59 #include "G4PhysicalConstants.hh"
60 #include "G4SystemOfUnits.hh"
61 #include "G4DynamicParticle.hh"
62 #include "G4ParticleDefinition.hh"
63 #include "G4Material.hh"
64 #include "G4Exp.hh"
65
66 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
67
68 G4IonYangFluctuationModel::G4IonYangFluctuationModel(const G4String& name)
69 : G4VLowEnergyModel(name)
70 {;}
71
72 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
73
74 G4IonYangFluctuationModel::~G4IonYangFluctuationModel()
75 {;}
76
77 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
78
79 G4double G4IonYangFluctuationModel::TheValue(const G4DynamicParticle* particle,
80 const G4Material* material)
81 {
82 G4double energy = particle->GetKineticEnergy() ;
83 G4double mass = particle->GetMass() ;
84 G4double charge = (particle->GetCharge())/eplus ;
85
86 G4double q = YangFluctuationModel(material,energy,mass,charge) ;
87
88 return q ;
89 }
90
91 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
92
93 G4double G4IonYangFluctuationModel::TheValue(const G4ParticleDefinition* aParticle,
94 const G4Material* material,
95 G4double kineticEnergy)
96 {
97 G4double mass = aParticle->GetPDGMass() ;
98 G4double charge = (aParticle->GetPDGCharge())/eplus ;
99
100 G4double q = YangFluctuationModel(material,kineticEnergy,mass,charge);
101
102 return q ;
103 }
104
105 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
106
107 G4double G4IonYangFluctuationModel::HighEnergyLimit(const G4ParticleDefinition*,
108 const G4Material*) const
109 {
110 return 1.0*TeV ;
111 }
112
113 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
114
115 G4double G4IonYangFluctuationModel::LowEnergyLimit(const G4ParticleDefinition* ,
116 const G4Material* ) const
117 {
118 return 0.0 ;
119 }
120
121 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
122
123 G4double G4IonYangFluctuationModel::HighEnergyLimit(const G4ParticleDefinition* ) const
124 {
125 return 1.0*TeV ;
126 }
127
128 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
129
130 G4double G4IonYangFluctuationModel::LowEnergyLimit(
131 const G4ParticleDefinition* ) const
132 {
133 return 0.0 ;
134 }
135
136 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
137
138 G4bool G4IonYangFluctuationModel::IsInCharge(const G4DynamicParticle*,
139 const G4Material* ) const
140 {
141 return true ;
142 }
143
144 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
145
146 G4bool G4IonYangFluctuationModel::IsInCharge(const G4ParticleDefinition* ,
147 const G4Material* ) const
148 {
149 return true ;
150 }
151
152 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
153
154 G4double G4IonYangFluctuationModel::YangFluctuationModel(const G4Material* material,
155 G4double kineticEnergy,
156 G4double particleMass,
157 G4double charge) const
158 {
159 // The aproximation of energy loss fluctuations
160 // Q.Yang et al., NIM B61(1991)149-155.
161
162 // Reduced energy in MeV/AMU
163 G4double energy = kineticEnergy *amu_c2/(particleMass*MeV) ;
164
165 G4int i = 0 ;
166 G4double factor = 1.0 ;
167
168 // The index of set of parameters i = 0 for protons(hadrons) in gases
169 // 1 for protons(hadrons) in solids
170 // 2 for ions in atomic gases
171 // 3 for ions in molecular gases
172 // 4 for ions in solids
173 static const G4double b[5][4] = {
174 {0.1014, 0.3700, 0.9642, 3.987},
175 {0.1955, 0.6941, 2.522, 1.040},
176 {0.05058, 0.08975, 0.1419, 10.80},
177 {0.05009, 0.08660, 0.2751, 3.787},
178 {0.01273, 0.03458, 0.3951, 3.812}
179 } ;
180
181 // protons (hadrons)
182 if(1.5 > charge) {
183 if( kStateGas != material->GetState() ) i = 1 ;
184
185 // ions
186 } else {
187 G4double zeff = (material->GetElectronDensity())/
188 (material->GetTotNbOfAtomsPerVolume()) ;
189 factor = charge * std::pow(charge/zeff, 0.3333) ;
190
191 if( kStateGas == material->GetState() ) {
192 energy /= (charge * std::sqrt(charge)) ;
193
194 if(1 == (material->GetNumberOfElements())) {
195 i = 2 ;
196 } else {
197 i = 3 ;
198 }
199
200 } else {
201 energy /= (charge * std::sqrt(charge*zeff)) ;
202 i = 4 ;
203 }
204 }
205
206 G4double x = b[i][2] * (1.0 - G4Exp( - energy * b[i][3] )) ;
207
208 G4double q = factor * x * b[i][0] /
209 ((energy - b[i][1])*(energy - b[i][1]) + x*x) ;
210
211 return q ;
212 }
213