Implementation of the JScatteringModel interface with Rayleigh scattering. More...

#include <JScatteringModel.hh>

Inheritance diagram for JMARKOV::JRayleighScattering:

Public Member Functions
	JRayleighScattering (double _lambda_scat, double _a)
	Constructor. More...

double	getScatteringProbability (double ct)
	Return the probability density as a function of cos(theta) More...

JVersor3D	generateDirection ()
	Return a randomly generated direction according to the scattering probability distribution. More...

virtual double	getScatteringLength ()

Protected Attributes
double	a

double	lambda_scat

Detailed Description

Implementation of the JScatteringModel interface with Rayleigh scattering.

Definition at line 472 of file JScatteringModel.hh.

Constructor & Destructor Documentation

JMARKOV::JRayleighScattering::JRayleighScattering	(	double	_lambda_scat,
		double	_a
	)

inline

Constructor.

note that one should never set a<0

Definition at line 481 of file JScatteringModel.hh.

                                                           {
       lambda_scat  = _lambda_scat ;
       a = _a ;
       if( fabs(a)<0 ) {
         cerr << "Fatal error in initialization of JRayleighScattering: a<0 !" << endl ;
         exit(1) ;
       }
     }

Member Function Documentation

double JMARKOV::JRayleighScattering::getScatteringProbability ( double ct )

inlinevirtual

Return the probability density as a function of cos(theta)

dP / dOmega = dP / dcosTheta dPhi

to scatter in a given direction. Theta=0 is forward scattering.

Implements JMARKOV::JScatteringModel.

Definition at line 490 of file JScatteringModel.hh.

                                                  {
       //double ct = cos(dir.getTheta()) ;
       return  (1+a*ct*ct)/(4.0*M_PI*(1+a/3.0)) ;
     }

JVersor3D JMARKOV::JRayleighScattering::generateDirection ( )

inlinevirtual

Return a randomly generated direction according to the scattering probability distribution.

This uses gRandom.

Implements JMARKOV::JScatteringModel.

Definition at line 495 of file JScatteringModel.hh.

                                   {
       double phi = gRandom->Uniform(0,2*M_PI) ;
       double ct ;
       if( a>0 ) {
         double xi  = gRandom->Uniform(0,1) ;
         double d0 = -9/a ;
         double d1 = 27.0*(1-2*xi)*(3+a)/a ;
         double C  = pow( 0.5*(d1 + sqrt(d1*d1-4*d0*d0*d0) ), 1.0/3.0 ) ;
         ct = -1.0/(3.0)*(C+d0/C) ;
       } else {
         ct = gRandom->Uniform(-1,1) ;
       }
       return JVersor3D( JAngle3D( acos(ct),phi) ) ;
     }