Jpp 19.3.0-rc.2
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JMARKOV::JRayleighScattering Class Reference

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

#include <JScatteringModel.hh>

Inheritance diagram for JMARKOV::JRayleighScattering:
JMARKOV::JScatteringModel

Public Member Functions

 JRayleighScattering (double _lambda_scat, double _a)
 Constructor.
 
double getScatteringProbability (double ct)
 Return the probability density as a function of cos(theta)
 
JVersor3D generateDirection ()
 Return a randomly generated direction according to the scattering probability distribution.
 
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

◆ JRayleighScattering()

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.

481 {
482 lambda_scat = _lambda_scat ;
483 a = _a ;
484 if( fabs(a)<0 ) {
485 cerr << "Fatal error in initialization of JRayleighScattering: a<0 !" << endl ;
486 exit(1) ;
487 }
488 }

Member Function Documentation

◆ getScatteringProbability()

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.

490 {
491 //double ct = cos(dir.getTheta()) ;
492 return (1+a*ct*ct)/(4.0*M_PI*(1+a/3.0)) ;
493 }

◆ generateDirection()

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.

495 {
496 double phi = gRandom->Uniform(0,2*M_PI) ;
497 double ct ;
498 if( a>0 ) {
499 double xi = gRandom->Uniform(0,1) ;
500 double d0 = -9/a ;
501 double d1 = 27.0*(1-2*xi)*(3+a)/a ;
502 double C = pow( 0.5*(d1 + sqrt(d1*d1-4*d0*d0*d0) ), 1.0/3.0 ) ;
503 ct = -1.0/(3.0)*(C+d0/C) ;
504 } else {
505 ct = gRandom->Uniform(-1,1) ;
506 }
507 return JDirection3D( JAngle3D( acos(ct),phi) ) ;
508 }
T pow(const T &x, const double y)
Power .
Definition JMath.hh:97

◆ getScatteringLength()

virtual double JMARKOV::JScatteringModel::getScatteringLength ( )
inlinevirtualinherited

Reimplemented in JMARKOV::JCombinedScattering.

Definition at line 72 of file JScatteringModel.hh.

72{ return lambda_scat ; }

Member Data Documentation

◆ a

double JMARKOV::JRayleighScattering::a
protected

Definition at line 512 of file JScatteringModel.hh.

◆ lambda_scat

double JMARKOV::JScatteringModel::lambda_scat
protectedinherited

Definition at line 76 of file JScatteringModel.hh.


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