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G4IonYangFluctuationModel.cc
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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 }