G4DynamicParticleFluctuation Class Reference

#include <G4DynamicParticleFluctuation.hh>

Inheritance diagram for G4DynamicParticleFluctuation:

Public Member Functions
	G4DynamicParticleFluctuation (const G4String &nam="dynPartFluc")
	~G4DynamicParticleFluctuation () override=default
G4double	SampleFluctuations (const G4MaterialCutsCouple *, const G4DynamicParticle *, const G4double, const G4double, const G4double, const G4double) override
G4double	Dispersion (const G4Material *, const G4DynamicParticle *, const G4double, const G4double, const G4double) override
G4DynamicParticleFluctuation &	operator= (const G4DynamicParticleFluctuation &right)=delete
	G4DynamicParticleFluctuation (const G4DynamicParticleFluctuation &)=delete
Public Member Functions inherited from G4UniversalFluctuation
	G4UniversalFluctuation (const G4String &nam="UniFluc")
	~G4UniversalFluctuation () override
G4double	SampleFluctuations (const G4MaterialCutsCouple *, const G4DynamicParticle *, const G4double, const G4double, const G4double, const G4double) override
G4double	Dispersion (const G4Material *, const G4DynamicParticle *, const G4double, const G4double, const G4double) override
void	InitialiseMe (const G4ParticleDefinition *) override
void	SetParticleAndCharge (const G4ParticleDefinition *, G4double q2) override
G4UniversalFluctuation &	operator= (const G4UniversalFluctuation &right)=delete
	G4UniversalFluctuation (const G4UniversalFluctuation &)=delete
Public Member Functions inherited from G4VEmFluctuationModel
	G4VEmFluctuationModel (const G4String &nam)
virtual	~G4VEmFluctuationModel ()
const G4String &	GetName () const
G4VEmFluctuationModel &	operator= (const G4VEmFluctuationModel &right)=delete
	G4VEmFluctuationModel (const G4VEmFluctuationModel &)=delete

Additional Inherited Members
Protected Member Functions inherited from G4UniversalFluctuation
virtual G4double	SampleGlandz (CLHEP::HepRandomEngine *rndm, const G4Material *, const G4double tcut)
void	AddExcitation (CLHEP::HepRandomEngine *rndm, const G4double ax, const G4double ex, G4double &eav, G4double &eloss, G4double &esig2)
void	SampleGauss (CLHEP::HepRandomEngine *rndm, const G4double eav, const G4double esig2, G4double &eloss)
Protected Attributes inherited from G4UniversalFluctuation
G4double	particleMass = 0.0
G4double	m_Inv_particleMass = DBL_MAX
G4double	m_massrate = DBL_MAX
G4double	chargeSquare = 1.0
G4double	ipotFluct = 0.0
G4double	ipotLogFluct = 0.0
G4double	e0 = 0.0
G4double	minNumberInteractionsBohr = 10.0
G4double	minLoss
G4double	nmaxCont = 8.0
G4double	rate = 0.56
G4double	fw = 4.0
G4double	a0 = 42.0
G4double	w2 = 0.0
G4double	meanLoss = 0.0
const G4ParticleDefinition *	particle = nullptr
G4double *	rndmarray = nullptr
G4int	sizearray = 30

Detailed Description

Definition at line 54 of file G4DynamicParticleFluctuation.hh.

Constructor & Destructor Documentation

G4DynamicParticleFluctuation() [1/2]

G4DynamicParticleFluctuation::G4DynamicParticleFluctuation

(

const G4String &

nam = "dynPartFluc"

)

Definition at line 55 of file G4DynamicParticleFluctuation.cc.

 : G4UniversalFluctuation(nam)
{}

Referenced by G4DynamicParticleFluctuation(), and operator=().

~G4DynamicParticleFluctuation()

G4DynamicParticleFluctuation::~G4DynamicParticleFluctuation ( )

overridedefault

G4DynamicParticleFluctuation() [2/2]

G4DynamicParticleFluctuation::G4DynamicParticleFluctuation ( const G4DynamicParticleFluctuation & )

delete

Member Function Documentation

Dispersion()

G4double G4DynamicParticleFluctuation::Dispersion ( const G4Material * material, const G4DynamicParticle * dp, const G4double tcut, const G4double tmax, const G4double length )

overridevirtual

Implements G4VEmFluctuationModel.

Definition at line 158 of file G4DynamicParticleFluctuation.cc.

{
  InitialiseLocal(dp);
  const G4double beta = dp->GetBeta();
  return (tmax/(beta*beta) - 0.5*tcut) * CLHEP::twopi_mc2_rcl2 * length
    * material->GetElectronDensity() * chargeSquare;
}

operator=()

G4DynamicParticleFluctuation & G4DynamicParticleFluctuation::operator= ( const G4DynamicParticleFluctuation & right )

delete

SampleFluctuations()

G4double G4DynamicParticleFluctuation::SampleFluctuations ( const G4MaterialCutsCouple * couple, const G4DynamicParticle * dp, const G4double tcut, const G4double tmax, const G4double length, const G4double averageLoss )

overridevirtual

Implements G4VEmFluctuationModel.

Definition at line 74 of file G4DynamicParticleFluctuation.cc.

{
  // Calculate actual loss from the mean loss.
  // The model used to get the fluctuations is essentially the same
  // as in Glandz in Geant3 (Cern program library W5013, phys332).
  // L. Urban et al. NIM A362, p.416 (1995) and Geant4 Physics Reference Manual
 
  // shortcut for very small loss or from a step nearly equal to the range
  // (out of validity of the model)
  //
  if (averageLoss < minLoss) { return averageLoss; }
  meanLoss = averageLoss;
  const G4double tkin = dp->GetKineticEnergy();
  //G4cout<< "Emean= "<< meanLoss<< " tmax= "<< tmax<< " L= "<<length<<G4endl;
 
  CLHEP::HepRandomEngine* rndmEngineF = G4Random::getTheEngine();
 
  InitialiseLocal(dp);             
  const G4double gam   = tkin * m_Inv_particleMass + 1.0;
  const G4double gam2  = gam*gam;
  const G4double beta  = dp->GetBeta(); 
  const G4double beta2 = beta*beta;
 
  G4double loss(0.), siga(0.);
 
  const G4Material* material = couple->GetMaterial();
  
  // Gaussian regime
  // for heavy particles only and conditions
  // for Gauusian fluct. has been changed 
  //
  if (particleMass > CLHEP::electron_mass_c2 &&
      meanLoss >= minNumberInteractionsBohr*tcut && tmax <= 2.*tcut) {
 
    siga = std::sqrt((tmax/beta2 - 0.5*tcut)*CLHEP::twopi_mc2_rcl2* 
                      length*chargeSquare*material->GetElectronDensity());
    const G4double sn = meanLoss/siga;
  
    // thick target case 
    if (sn >= 2.0) {
 
      const G4double twomeanLoss = meanLoss + meanLoss;
      do {
    loss = G4RandGauss::shoot(rndmEngineF, meanLoss, siga);
    // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
      } while  (0.0 > loss || twomeanLoss < loss);
 
      // Gamma distribution
    } else {
 
      const G4double neff = sn*sn;
      loss = meanLoss*G4RandGamma::shoot(rndmEngineF, neff, 1.0)/neff;
    }
    //G4cout << "Gauss: " << loss << G4endl;
    return loss;
  }
 
  auto ioni = material->GetIonisation();
  e0 = ioni->GetEnergy0fluct();
 
  // very small step or low-density material
  if(tcut <= e0) { return meanLoss; }
 
  ipotFluct = ioni->GetMeanExcitationEnergy();
  ipotLogFluct = ioni->GetLogMeanExcEnergy();
 
  // width correction for small cuts
  const G4double scaling = std::min(1.+0.5*CLHEP::keV/tcut, 1.50);
  meanLoss /= scaling;
 
  w2 = (tcut > ipotFluct) ? 
    G4Log(2.*CLHEP::electron_mass_c2*beta2*gam2) - beta2 : 0.0;
  return SampleGlandz(rndmEngineF, material, tcut)*scaling;
}

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

• G4DynamicParticleFluctuation.hh
• G4DynamicParticleFluctuation.cc