Geant4 9.6.0
Toolkit for the simulation of the passage of particles through matter
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Public Member Functions | List of all members
G4BetheHeitlerModel Class Reference

#include <G4BetheHeitlerModel.hh>

+ Inheritance diagram for G4BetheHeitlerModel:

Public Member Functions

 G4BetheHeitlerModel (const G4ParticleDefinition *p=0, const G4String &nam="BetheHeitler")
 
virtual ~G4BetheHeitlerModel ()
 
virtual void Initialise (const G4ParticleDefinition *, const G4DataVector &)
 
virtual G4double ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double kinEnergy, G4double Z, G4double A=0., G4double cut=0., G4double emax=DBL_MAX)
 
virtual void SampleSecondaries (std::vector< G4DynamicParticle * > *, const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double tmin, G4double maxEnergy)
 
- Public Member Functions inherited from G4VEmModel
 G4VEmModel (const G4String &nam)
 
virtual ~G4VEmModel ()
 
virtual void Initialise (const G4ParticleDefinition *, const G4DataVector &)=0
 
virtual void SampleSecondaries (std::vector< G4DynamicParticle * > *, const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double tmin=0.0, G4double tmax=DBL_MAX)=0
 
virtual G4double ComputeDEDXPerVolume (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=DBL_MAX)
 
virtual G4double CrossSectionPerVolume (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
virtual G4double ComputeCrossSectionPerAtom (const G4ParticleDefinition *, G4double kinEnergy, G4double Z, G4double A=0., G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
virtual G4double ChargeSquareRatio (const G4Track &)
 
virtual G4double GetChargeSquareRatio (const G4ParticleDefinition *, const G4Material *, G4double kineticEnergy)
 
virtual G4double GetParticleCharge (const G4ParticleDefinition *, const G4Material *, G4double kineticEnergy)
 
virtual void StartTracking (G4Track *)
 
virtual void CorrectionsAlongStep (const G4MaterialCutsCouple *, const G4DynamicParticle *, G4double &eloss, G4double &niel, G4double length)
 
virtual G4double Value (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy)
 
virtual G4double MinPrimaryEnergy (const G4Material *, const G4ParticleDefinition *)
 
virtual void SetupForMaterial (const G4ParticleDefinition *, const G4Material *, G4double kineticEnergy)
 
virtual void DefineForRegion (const G4Region *)
 
void InitialiseElementSelectors (const G4ParticleDefinition *, const G4DataVector &)
 
G4double ComputeDEDX (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=DBL_MAX)
 
G4double CrossSection (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
G4double ComputeMeanFreePath (const G4ParticleDefinition *, G4double kineticEnergy, const G4Material *, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
G4double ComputeCrossSectionPerAtom (const G4ParticleDefinition *, const G4Element *, G4double kinEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
G4int SelectIsotopeNumber (const G4Element *)
 
const G4Element * SelectRandomAtom (const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
const G4Element * SelectRandomAtom (const G4Material *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
 
void SetParticleChange (G4VParticleChange *, G4VEmFluctuationModel *f=0)
 
void SetCrossSectionTable (G4PhysicsTable *)
 
G4PhysicsTable * GetCrossSectionTable ()
 
G4VEmFluctuationModel * GetModelOfFluctuations ()
 
G4VEmAngularDistribution * GetAngularDistribution ()
 
void SetAngularDistribution (G4VEmAngularDistribution *)
 
G4double HighEnergyLimit () const
 
G4double LowEnergyLimit () const
 
G4double HighEnergyActivationLimit () const
 
G4double LowEnergyActivationLimit () const
 
G4double PolarAngleLimit () const
 
G4double SecondaryThreshold () const
 
G4bool LPMFlag () const
 
G4bool DeexcitationFlag () const
 
G4bool ForceBuildTableFlag () const
 
void SetHighEnergyLimit (G4double)
 
void SetLowEnergyLimit (G4double)
 
void SetActivationHighEnergyLimit (G4double)
 
void SetActivationLowEnergyLimit (G4double)
 
G4bool IsActive (G4double kinEnergy)
 
void SetPolarAngleLimit (G4double)
 
void SetSecondaryThreshold (G4double)
 
void SetLPMFlag (G4bool val)
 
void SetDeexcitationFlag (G4bool val)
 
void ForceBuildTable (G4bool val)
 
G4double MaxSecondaryKinEnergy (const G4DynamicParticle *dynParticle)
 
const G4String & GetName () const
 
void SetCurrentCouple (const G4MaterialCutsCouple *)
 
const G4Element * GetCurrentElement () const
 

Additional Inherited Members

- Protected Member Functions inherited from G4VEmModel
G4ParticleChangeForLoss * GetParticleChangeForLoss ()
 
G4ParticleChangeForGamma * GetParticleChangeForGamma ()
 
virtual G4double MaxSecondaryEnergy (const G4ParticleDefinition *, G4double kineticEnergy)
 
const G4MaterialCutsCouple * CurrentCouple () const
 
void SetCurrentElement (const G4Element *)
 
- Protected Attributes inherited from G4VEmModel
G4VParticleChange * pParticleChange
 
G4PhysicsTable * xSectionTable
 
const std::vector< G4double > * theDensityFactor
 
const std::vector< G4int > * theDensityIdx
 

Detailed Description

Definition at line 58 of file G4BetheHeitlerModel.hh.

Constructor & Destructor Documentation

◆ G4BetheHeitlerModel()

G4BetheHeitlerModel::G4BetheHeitlerModel ( const G4ParticleDefinition *  p = 0,
const G4String &  nam = "BetheHeitler" 
)

Definition at line 68 of file G4BetheHeitlerModel.cc.

70 : G4VEmModel(nam)
71{
72 fParticleChange = 0;
73 theGamma = G4Gamma::Gamma();
74 thePositron = G4Positron::Positron();
75 theElectron = G4Electron::Electron();
76}
G4Electron::Electron
static G4Electron * Electron()
Definition: G4Electron.cc:94
G4Gamma::Gamma
static G4Gamma * Gamma()
Definition: G4Gamma.cc:86
G4Positron::Positron
static G4Positron * Positron()
Definition: G4Positron.cc:94

◆ ~G4BetheHeitlerModel()

G4BetheHeitlerModel::~G4BetheHeitlerModel ( )
virtual

Definition at line 80 of file G4BetheHeitlerModel.cc.

81{}

Member Function Documentation

◆ ComputeCrossSectionPerAtom()

G4double G4BetheHeitlerModel::ComputeCrossSectionPerAtom ( const G4ParticleDefinition *  ,
G4double  kinEnergy,
G4double  Z,
G4double  A = 0.,
G4double  cut = 0.,
G4double  emax = DBL_MAX 
)
virtual

Reimplemented from G4VEmModel.

Definition at line 95 of file G4BetheHeitlerModel.cc.

104{
105 static const G4double GammaEnergyLimit = 1.5*MeV;
106 G4double xSection = 0.0 ;
107 if ( Z < 0.9 || GammaEnergy <= 2.0*electron_mass_c2 ) { return xSection; }
108
109 static const G4double
110 a0= 8.7842e+2*microbarn, a1=-1.9625e+3*microbarn, a2= 1.2949e+3*microbarn,
111 a3=-2.0028e+2*microbarn, a4= 1.2575e+1*microbarn, a5=-2.8333e-1*microbarn;
112
113 static const G4double
114 b0=-1.0342e+1*microbarn, b1= 1.7692e+1*microbarn, b2=-8.2381 *microbarn,
115 b3= 1.3063 *microbarn, b4=-9.0815e-2*microbarn, b5= 2.3586e-3*microbarn;
116
117 static const G4double
118 c0=-4.5263e+2*microbarn, c1= 1.1161e+3*microbarn, c2=-8.6749e+2*microbarn,
119 c3= 2.1773e+2*microbarn, c4=-2.0467e+1*microbarn, c5= 6.5372e-1*microbarn;
120
121 G4double GammaEnergySave = GammaEnergy;
122 if (GammaEnergy < GammaEnergyLimit) { GammaEnergy = GammaEnergyLimit; }
123
124 G4double X=log(GammaEnergy/electron_mass_c2), X2=X*X, X3=X2*X, X4=X3*X, X5=X4*X;
125
126 G4double F1 = a0 + a1*X + a2*X2 + a3*X3 + a4*X4 + a5*X5,
127 F2 = b0 + b1*X + b2*X2 + b3*X3 + b4*X4 + b5*X5,
128 F3 = c0 + c1*X + c2*X2 + c3*X3 + c4*X4 + c5*X5;
129
130 xSection = (Z + 1.)*(F1*Z + F2*Z*Z + F3);
131
132 if (GammaEnergySave < GammaEnergyLimit) {
133
134 X = (GammaEnergySave - 2.*electron_mass_c2)
135 / (GammaEnergyLimit - 2.*electron_mass_c2);
136 xSection *= X*X;
137 }
138
139 if (xSection < 0.) { xSection = 0.; }
140 return xSection;
141}
G4double
double G4double
Definition: G4Types.hh:64

◆ Initialise()

void G4BetheHeitlerModel::Initialise ( const G4ParticleDefinition *  p,
const G4DataVector &  cuts 
)
virtual

Implements G4VEmModel.

Reimplemented in G4PolarizedGammaConversionModel.

Definition at line 85 of file G4BetheHeitlerModel.cc.

87{
88 if(!fParticleChange) { fParticleChange = GetParticleChangeForGamma(); }
89 InitialiseElementSelectors(p, cuts);
90}
G4VEmModel::GetParticleChangeForGamma
G4ParticleChangeForGamma * GetParticleChangeForGamma()
Definition: G4VEmModel.cc:109
G4VEmModel::InitialiseElementSelectors
void InitialiseElementSelectors(const G4ParticleDefinition *, const G4DataVector &)
Definition: G4VEmModel.cc:123

Referenced by G4PolarizedGammaConversionModel::Initialise().

◆ SampleSecondaries()

void G4BetheHeitlerModel::SampleSecondaries ( std::vector< G4DynamicParticle * > *  fvect,
const G4MaterialCutsCouple *  couple,
const G4DynamicParticle *  aDynamicGamma,
G4double  tmin,
G4double  maxEnergy 
)
virtual

Implements G4VEmModel.

Reimplemented in G4PolarizedGammaConversionModel.

Definition at line 145 of file G4BetheHeitlerModel.cc.

162{
163 const G4Material* aMaterial = couple->GetMaterial();
164
165 G4double GammaEnergy = aDynamicGamma->GetKineticEnergy();
166 G4ParticleMomentum GammaDirection = aDynamicGamma->GetMomentumDirection();
167
168 G4double epsil ;
169 G4double epsil0 = electron_mass_c2/GammaEnergy ;
170 if(epsil0 > 1.0) { return; }
171
172 // do it fast if GammaEnergy < 2. MeV
173 static const G4double Egsmall=2.*MeV;
174
175 // select randomly one element constituing the material
176 const G4Element* anElement = SelectRandomAtom(aMaterial, theGamma, GammaEnergy);
177
178 if (GammaEnergy < Egsmall) {
179
180 epsil = epsil0 + (0.5-epsil0)*G4UniformRand();
181
182 } else {
183 // now comes the case with GammaEnergy >= 2. MeV
184
185 // Extract Coulomb factor for this Element
186 G4double FZ = 8.*(anElement->GetIonisation()->GetlogZ3());
187 if (GammaEnergy > 50.*MeV) { FZ += 8.*(anElement->GetfCoulomb()); }
188
189 // limits of the screening variable
190 G4double screenfac = 136.*epsil0/(anElement->GetIonisation()->GetZ3());
191 G4double screenmax = exp ((42.24 - FZ)/8.368) - 0.952 ;
192 G4double screenmin = min(4.*screenfac,screenmax);
193
194 // limits of the energy sampling
195 G4double epsil1 = 0.5 - 0.5*sqrt(1. - screenmin/screenmax) ;
196 G4double epsilmin = max(epsil0,epsil1) , epsilrange = 0.5 - epsilmin;
197
198 //
199 // sample the energy rate of the created electron (or positron)
200 //
201 //G4double epsil, screenvar, greject ;
202 G4double screenvar, greject ;
203
204 G4double F10 = ScreenFunction1(screenmin) - FZ;
205 G4double F20 = ScreenFunction2(screenmin) - FZ;
206 G4double NormF1 = max(F10*epsilrange*epsilrange,0.);
207 G4double NormF2 = max(1.5*F20,0.);
208
209 do {
210 if ( NormF1/(NormF1+NormF2) > G4UniformRand() ) {
211 epsil = 0.5 - epsilrange*pow(G4UniformRand(), 0.333333);
212 screenvar = screenfac/(epsil*(1-epsil));
213 greject = (ScreenFunction1(screenvar) - FZ)/F10;
214
215 } else {
216 epsil = epsilmin + epsilrange*G4UniformRand();
217 screenvar = screenfac/(epsil*(1-epsil));
218 greject = (ScreenFunction2(screenvar) - FZ)/F20;
219 }
220
221 } while( greject < G4UniformRand() );
222
223 } // end of epsil sampling
224
225 //
226 // fixe charges randomly
227 //
228
229 G4double ElectTotEnergy, PositTotEnergy;
230 if (G4UniformRand() > 0.5) {
231
232 ElectTotEnergy = (1.-epsil)*GammaEnergy;
233 PositTotEnergy = epsil*GammaEnergy;
234
235 } else {
236
237 PositTotEnergy = (1.-epsil)*GammaEnergy;
238 ElectTotEnergy = epsil*GammaEnergy;
239 }
240
241 //
242 // scattered electron (positron) angles. ( Z - axis along the parent photon)
243 //
244 // universal distribution suggested by L. Urban
245 // (Geant3 manual (1993) Phys211),
246 // derived from Tsai distribution (Rev Mod Phys 49,421(1977))
247
248 G4double u;
249 const G4double a1 = 0.625 , a2 = 3.*a1 , d = 27. ;
250
251 if (9./(9.+d) >G4UniformRand()) u= - log(G4UniformRand()*G4UniformRand())/a1;
252 else u= - log(G4UniformRand()*G4UniformRand())/a2;
253
254 G4double TetEl = u*electron_mass_c2/ElectTotEnergy;
255 G4double TetPo = u*electron_mass_c2/PositTotEnergy;
256 G4double Phi = twopi * G4UniformRand();
257 G4double dxEl= sin(TetEl)*cos(Phi),dyEl= sin(TetEl)*sin(Phi),dzEl=cos(TetEl);
258 G4double dxPo=-sin(TetPo)*cos(Phi),dyPo=-sin(TetPo)*sin(Phi),dzPo=cos(TetPo);
259
260 //
261 // kinematic of the created pair
262 //
263 // the electron and positron are assumed to have a symetric
264 // angular distribution with respect to the Z axis along the parent photon.
265
266 G4double ElectKineEnergy = max(0.,ElectTotEnergy - electron_mass_c2);
267
268 G4ThreeVector ElectDirection (dxEl, dyEl, dzEl);
269 ElectDirection.rotateUz(GammaDirection);
270
271 // create G4DynamicParticle object for the particle1
272 G4DynamicParticle* aParticle1= new G4DynamicParticle(
273 theElectron,ElectDirection,ElectKineEnergy);
274
275 // the e+ is always created (even with Ekine=0) for further annihilation.
276
277 G4double PositKineEnergy = max(0.,PositTotEnergy - electron_mass_c2);
278
279 G4ThreeVector PositDirection (dxPo, dyPo, dzPo);
280 PositDirection.rotateUz(GammaDirection);
281
282 // create G4DynamicParticle object for the particle2
283 G4DynamicParticle* aParticle2= new G4DynamicParticle(
284 thePositron,PositDirection,PositKineEnergy);
285
286 // Fill output vector
287 fvect->push_back(aParticle1);
288 fvect->push_back(aParticle2);
289
290 // kill incident photon
291 fParticleChange->SetProposedKineticEnergy(0.);
292 fParticleChange->ProposeTrackStatus(fStopAndKill);
293}
F10
#define F10
Definition: G4ErrorMatrix.cc:894
F20
#define F20
Definition: G4ErrorMatrix.cc:899
fStopAndKill
@ fStopAndKill
Definition: G4TrackStatus.hh:56
G4UniformRand
#define G4UniformRand()
Definition: Randomize.hh:53
G4DynamicParticle::GetMomentumDirection
const G4ThreeVector & GetMomentumDirection() const
G4DynamicParticle::GetKineticEnergy
G4double GetKineticEnergy() const
G4Element::GetfCoulomb
G4double GetfCoulomb() const
Definition: G4Element.hh:201
G4Element::GetIonisation
G4IonisParamElm * GetIonisation() const
Definition: G4Element.hh:209
G4IonisParamElm::GetlogZ3
G4double GetlogZ3() const
Definition: G4IonisParamElm.hh:63
G4IonisParamElm::GetZ3
G4double GetZ3() const
Definition: G4IonisParamElm.hh:61
G4MaterialCutsCouple::GetMaterial
const G4Material * GetMaterial() const
Definition: G4MaterialCutsCouple.hh:150
G4ParticleChangeForGamma::SetProposedKineticEnergy
void SetProposedKineticEnergy(G4double proposedKinEnergy)
Definition: G4ParticleChangeForGamma.hh:129
G4VEmModel::SelectRandomAtom
const G4Element * SelectRandomAtom(const G4MaterialCutsCouple *, const G4ParticleDefinition *, G4double kineticEnergy, G4double cutEnergy=0.0, G4double maxEnergy=DBL_MAX)
Definition: G4VEmModel.hh:459
G4VParticleChange::ProposeTrackStatus
void ProposeTrackStatus(G4TrackStatus status)

Referenced by G4PolarizedGammaConversionModel::SampleSecondaries().

The documentation for this class was generated from the following files: