G4RayleighAngularGenerator Class Reference

#include <G4RayleighAngularGenerator.hh>

Inheritance diagram for G4RayleighAngularGenerator:

Collaboration diagram for G4RayleighAngularGenerator:

Public Member Functions
	G4RayleighAngularGenerator ()
virtual	~G4RayleighAngularGenerator ()
virtual G4ThreeVector &	SampleDirection (const G4DynamicParticle *dp, G4double out_energy, G4int Z, const G4Material *mat=0)
Public Member Functions inherited from G4VEmAngularDistribution
	G4VEmAngularDistribution (const G4String &name)
virtual	~G4VEmAngularDistribution ()
virtual G4ThreeVector &	SampleDirectionForShell (const G4DynamicParticle *dp, G4double finalTotalEnergy, G4int Z, G4int shellID, const G4Material *)
const G4String &	GetName () const

Additional Inherited Members
Protected Attributes inherited from G4VEmAngularDistribution
G4ThreeVector	fLocalDirection

Detailed Description

Definition at line 61 of file G4RayleighAngularGenerator.hh.

Constructor & Destructor Documentation

G4RayleighAngularGenerator::G4RayleighAngularGenerator

(

)

Definition at line 66 of file G4RayleighAngularGenerator.cc.

  : G4VEmAngularDistribution("CullenGenerator")
{
  G4double x = cm/(h_Planck*c_light);
  fFactor = 0.5*x*x;
}

G4RayleighAngularGenerator::~G4RayleighAngularGenerator ( )

virtual

Definition at line 75 of file G4RayleighAngularGenerator.cc.

{}

Member Function Documentation

G4ThreeVector & G4RayleighAngularGenerator::SampleDirection ( const G4DynamicParticle *  dp, G4double  out_energy, G4int  Z, const G4Material *  mat = 0  )

virtual

Implements G4VEmAngularDistribution.

Definition at line 81 of file G4RayleighAngularGenerator.cc.

{
  G4double ekin = dp->GetKineticEnergy();
  G4double xx = fFactor*ekin*ekin;
  G4double cost;

  G4double n0 = PP6[Z] - 1.0;
  G4double n1 = PP7[Z] - 1.0;
  G4double n2 = PP8[Z] - 1.0;
  G4double b0 = PP3[Z];
  G4double b1 = PP4[Z];
  G4double b2 = PP5[Z];
  G4double w0 = 0.0;
  G4double w1 = 0.0;
  G4double w2 = 0.0;

  const G4double numlim = 0.02;
  G4double x  = 2*xx*b0;
  if(x < numlim)   { w0 = n0*x*(1 - 0.5*(n0 - 1)*x*(1 - (n0 - 2)*x/3.)); }
  else             { w0 = 1 - G4Exp(-n0*G4Log(1 + x)); }

  if(PP1[Z] > 0.0) {
    x  = 2*xx*b1;
    if(x < numlim) { w1 = n1*x*(1 - 0.5*(n1 - 1)*x*(1 - (n1 - 2)*x/3.)); }
    else           { w1 = 1 - G4Exp(-n1*G4Log(1 + x)); }
  }
  if(PP2[Z] > 0.0) {
    x  = 2*xx*b2;
    if(x < numlim) { w2 = n2*x*(1 - 0.5*(n2 - 1)*x*(1 - (n2 - 2)*x/3.)); }
    else           { w2 = 1 - G4Exp(-n2*G4Log(1 + x)); }
  }

  G4double x0= w0*PP0[Z]/(b0*n0);
  G4double x1= w1*PP1[Z]/(b1*n1);
  G4double x2= w2*PP2[Z]/(b2*n2);

  do {

    G4double w = w0;
    G4double n = n0;
    G4double b = b0;
  
    x = G4UniformRand()*(x0 + x1 + x2);
    if(x > x0) {
      x -= x0;
      if(x <= x1 ) {
    w = w1;
    n = n1;
    b = b1;
      } else { 
    w = w2;
    n = n2;
    b = b2;
      }
    }
    n = 1.0/n;

    // sampling of angle
    G4double y = w*G4UniformRand();
    if(y < numlim) { x = y*n*( 1 + 0.5*(n + 1)*y*(1 - (n + 2)*y/3.)); }
    //else           { x = 1.0/std::pow(1 - y, n) - 1.0; }
    else           { x = G4Exp(-n*G4Log(1 - y)) - 1.0; }
    cost = 1.0 - x/(b*xx);
    //G4cout << "cost = " << cost << " w= " << w << " n= " << n 
    //     << " b= " << b << " x= " << x << " xx= " << xx << G4endl;  
  } while (2*G4UniformRand() > 1.0 + cost*cost || cost < -1.0);

  G4double phi  = twopi*G4UniformRand();
  G4double sint = sqrt((1. - cost)*(1.0 + cost));
  fLocalDirection.set(sint*cos(phi),sint*sin(phi),cost);
  fLocalDirection.rotateUz(dp->GetMomentumDirection());

  return fLocalDirection;
}

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

• source/geant4.10.03.p02/source/processes/electromagnetic/lowenergy/include/G4RayleighAngularGenerator.hh
• source/geant4.10.03.p02/source/processes/electromagnetic/lowenergy/src/G4RayleighAngularGenerator.cc