iFatras::ProcessSamplingTool Class Reference

Fatras AlgTool to sample process and free path. More...

#include <ProcessSamplingTool.h>

Inheritance diagram for iFatras::ProcessSamplingTool:

Collaboration diagram for iFatras::ProcessSamplingTool:

Public Member Functions
	ProcessSamplingTool (const std::string &, const std::string &, const IInterface *)
	Constructor.
virtual	~ProcessSamplingTool ()=default
	Destructor.
Trk::PathLimit	sampleProcess (CLHEP::HepRandomEngine *randomEngine, double mom, double charge, Trk::ParticleHypothesis pHypothesis) const
	Process pre-sampling : to be moved into material updators eventually.

Private Attributes
BooleanProperty	m_hadInt {this, "HadronicInteraction", true, ""}
	hadronic interaction

Detailed Description

Fatras AlgTool to sample process and free path.

Author

Sharka Todorova Sarka.Todorova -at- cern.ch

Definition at line 28 of file ProcessSamplingTool.h.

Constructor & Destructor Documentation

ProcessSamplingTool()

iFatras::ProcessSamplingTool::ProcessSamplingTool	(	const std::string &	t,
		const std::string &	n,
		const IInterface *	p )

Constructor.

Definition at line 25 of file ProcessSamplingTool.cxx.

  : base_class(t,n,p)
{
}

~ProcessSamplingTool()

virtual iFatras::ProcessSamplingTool::~ProcessSamplingTool ( )

virtualdefault

Destructor.

Member Function Documentation

sampleProcess()

Trk::PathLimit iFatras::ProcessSamplingTool::sampleProcess	(	CLHEP::HepRandomEngine *	randomEngine,
		double	mom,
		double	charge,
		Trk::ParticleHypothesis	pHypothesis ) const

Process pre-sampling : to be moved into material updators eventually.

Definition at line 33 of file ProcessSamplingTool.cxx.

{
  int process=0;
  double x0Max = -1.;
 
  if ( particle == Trk::electron && charge<0. ) return Trk::PathLimit(x0Max,process);
 
  if ( particle == Trk::muon || particle == Trk::nonInteractingMuon ) return Trk::PathLimit(x0Max,process);
 
  double rndx = CLHEP::RandFlat::shoot(randomEngine);
 
  if ( particle == Trk::photon ) {
 
    // conversion (14), compton effect (13), photo-effect (12)
 
    double  p0  =       -7.01612e-03;
    double  p1  =        7.69040e-02;
    double  p2  =       -6.07682e-01;
    // calculate xi
    double xi = p0 + p1*pow(momentum/1000.,p2);
    double attenuation = -7.777e-01*(1.-xi);
 
    x0Max = log(rndx)/attenuation ;
 
    // comment additional interactions till properly implemented
    /*
    // first estimate : compton ~ 4% , use attenuation factor as for conversion (till parameterized )
    double rndp = CLHEP::RandFlat::shoot(randomEngine);
 
    if ( rndp > 0.96 ) { // do Compton scattering
      process = 13;
    } else if (rndp < 5.53/pow(momentum,1.184) ) {
      process = 12;
      attenuation = -0.378;
      x0Max = log(rndx)/attenuation *momentum ;
    } else {
      process = 14;
      //x0Max *= 0.5;
    }
    */
 
    process = 14;
 
    return Trk::PathLimit(x0Max,process);
  }
 
  if ( particle == Trk::electron && charge>0. ) {   // positron
 
    double mass = Trk::ParticleMasses::mass[Trk::electron];
    double gamma = momentum/mass;
 
    // annihilation
    // energy dependent factor
    double fpa = log(2*gamma)/gamma;
    // material dependent factor - use Al(Z=13) for the moment
    double fza = 13.;
    double attenuation = -fpa*fza; // adjust
 
    x0Max = log(rndx)/attenuation ;
    process = 5;
 
    return Trk::PathLimit(x0Max,process);
 
  }
 
  // presumably here we are left with hadrons only
  if (m_hadInt) {
 
    // sample free path in terms of nuclear interaction length
    double al = 1.;          // scaling here
 
    /*
 
      if ( particle == Trk::pion || particle == Trk::kaon || particle == Trk::pi0 || particle == Trk::k0) {
      al *= 1./(1.+ exp(-0.5*(momentum-270.)*(momentum-270.)/60./60.));
      }
      if ( particle == Trk::proton || particle == Trk::neutron ) al *=0.7;
      if ( particle == Trk::pion || particle == Trk::pi0) al *=0.9;
    */
 
    x0Max = -log(rndx)*al ;
 
    process = 121;
 
    //std::cout <<"hadronic path limit:"<<momentum<<","<<al<<","<< x0Max << std::endl;
    return Trk::PathLimit(x0Max,process);
  }
 
 
  return Trk::PathLimit(x0Max,process);
 
}

Member Data Documentation

m_hadInt

BooleanProperty iFatras::ProcessSamplingTool::m_hadInt {this, "HadronicInteraction", true, ""}

private

hadronic interaction

Definition at line 45 of file ProcessSamplingTool.h.

{this, "HadronicInteraction", true, ""};

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

• ProcessSamplingTool.h
• ProcessSamplingTool.cxx