#include <EnergyLossSimulator.h>

Inheritance diagram for EnergyLossSimulator:

Public Member Functions
const XYZTLorentzVector &	deltaMom () const
	Returns the actual energy lost. More...

	EnergyLossSimulator (double A, double Z, double density, double radLen)
	Constructor. More...

double	mostLikelyLoss () const
	Return most probable energy loss. More...

	~EnergyLossSimulator () override
	Default Destructor. More...

Public Member Functions inherited from MaterialEffectsSimulator
RHEP_const_iter	beginDaughters () const
	Returns const iterator to the beginning of the daughters list. More...

int	closestDaughterId ()
	The id of the closest charged daughter (filled for nuclear interactions only) More...

double	eMass () const
	Electron mass in GeV/c2. More...

RHEP_const_iter	endDaughters () const
	Returns const iterator to the end of the daughters list. More...

double	excitE () const
	Mean excitation energy (in GeV) More...

	MaterialEffectsSimulator (double A=28.0855, double Z=14.0000, double density=2.329, double radLen=9.360)

unsigned	nDaughters () const
	Returns the number of daughters. More...

XYZVector	orthogonal (const XYZVector &) const
	A vector orthogonal to another one (because it's not in XYZTLorentzVector) More...

double	radLenIncm () const
	One radiation length in cm. More...

double	rho () const
	Density in g/cm3. More...

virtual void	save ()
	Used by NuclearInteractionSimulator to save last sampled event. More...

void	setNormalVector (const GlobalVector &normal)
	Sets the vector normal to the surface traversed. More...

double	theA () const
	A. More...

double	theZ () const
	Z. More...

void	updateState (ParticlePropagator &myTrack, double radlen, RandomEngineAndDistribution const *)
	Compute the material effect (calls the sub class) More...

virtual	~MaterialEffectsSimulator ()

Private Member Functions
void	compute (ParticlePropagator &Particle, RandomEngineAndDistribution const *) override
	The real dE/dx generation and particle update. More...

Private Attributes
XYZTLorentzVector	deltaP
	The actual energy loss. More...

double	mostProbableLoss
	The most probable enery loss. More...

LandauFluctuationGenerator *	theGenerator
	The Landau Fluctuation generator. More...

Additional Inherited Members
Public Types inherited from MaterialEffectsSimulator
typedef std::vector< RawParticle >::const_iterator	RHEP_const_iter

Protected Attributes inherited from MaterialEffectsSimulator
std::vector< RawParticle >	_theUpdatedState

double	A

double	density

double	radLen

double	radLengths

int	theClosestChargedDaughterId

GlobalVector	theNormalVector

double	Z

Detailed Description

Definition at line 25 of file EnergyLossSimulator.h.

Constructor & Destructor Documentation

◆ EnergyLossSimulator()

EnergyLossSimulator::EnergyLossSimulator	(	double	A,
		double	Z,
		double	density,
		double	radLen
	)

Constructor.

Definition at line 7 of file EnergyLossSimulator.cc.

     : MaterialEffectsSimulator(A, Z, density, radLen) {
   theGenerator = new LandauFluctuationGenerator();
 }

References theGenerator.

◆ ~EnergyLossSimulator()

EnergyLossSimulator::~EnergyLossSimulator ( )

override

Default Destructor.

Definition at line 12 of file EnergyLossSimulator.cc.

12 { delete theGenerator; }

References theGenerator.

Member Function Documentation

◆ compute()

void EnergyLossSimulator::compute	(	ParticlePropagator &	Particle,
		RandomEngineAndDistribution const *	random
	)

overrideprivatevirtual

The real dE/dx generation and particle update.

Implements MaterialEffectsSimulator.

Definition at line 14 of file EnergyLossSimulator.cc.

                                                                                                          {
   //  FamosHistos* myHistos = FamosHistos::instance();
  
   // double gamma_e = 0.577215664901532861;  // Euler constant
  
   // The thickness in cm
   double thick = radLengths * radLenIncm();
  
   // This is a simple version (a la PDG) of a dE/dx generator.
   // It replaces the buggy GEANT3 -> C++ former version.
   // Author : Patrick Janot - 8-Jan-2004
  
   double p2 = Particle.particle().Vect().Mag2();
   double verySmallP2 = 0.0001;
   if (p2 <= verySmallP2) {
     deltaP.SetXYZT(0., 0., 0., 0.);
     return;
   }
   double m2 = Particle.particle().mass() * Particle.particle().mass();
   double e2 = p2 + m2;
  
   double beta2 = p2 / e2;
   double gama2 = e2 / m2;
  
   double charge2 = Particle.particle().charge() * Particle.particle().charge();
  
   // Energy loss spread in GeV
   double eSpread = 0.1536E-3 * charge2 * (theZ() / theA()) * rho() * thick / beta2;
  
   // Most probable energy loss (from the integrated Bethe-Bloch equation)
   mostProbableLoss = eSpread * (log(2. * eMass() * beta2 * gama2 * eSpread / (excitE() * excitE())) - beta2 + 0.200);
  
   // This one can be needed on output (but is not used internally)
   // meanEnergyLoss = 2.*eSpread * ( log ( 2.*eMass()*beta2*gama2 /excitE() ) - beta2 );
  
   // Generate the energy loss with Landau fluctuations
   double dedx = mostProbableLoss + eSpread * theGenerator->landau(random);
  
   // Compute the new energy and momentum
   double aBitAboveMass = Particle.particle().mass() * 1.0001;
   double newE = std::max(aBitAboveMass, Particle.particle().e() - dedx);
   //  double newE = std::max(Particle.particle().mass(),Particle.particle().e()-dedx);
   double fac = std::sqrt((newE * newE - m2) / p2);
  
   // Update the momentum
   deltaP.SetXYZT(Particle.particle().Px() * (1. - fac),
                  Particle.particle().Py() * (1. - fac),
                  Particle.particle().Pz() * (1. - fac),
                  Particle.particle().E() - newE);
   Particle.particle().setMomentum(
       Particle.particle().Px() * fac, Particle.particle().Py() * fac, Particle.particle().Pz() * fac, newE);
 }

References deltaP, MaterialEffectsSimulator::eMass(), MaterialEffectsSimulator::excitE(), LandauFluctuationGenerator::landau(), dqm-mbProfile::log, SiStripPI::max, mostProbableLoss, p2, MaterialEffectsSimulator::radLengths, MaterialEffectsSimulator::radLenIncm(), MaterialEffectsSimulator::rho(), mathSSE::sqrt(), MaterialEffectsSimulator::theA(), theGenerator, and MaterialEffectsSimulator::theZ().

◆ deltaMom()

const XYZTLorentzVector& EnergyLossSimulator::deltaMom ( ) const

inline

Returns the actual energy lost.

Definition at line 37 of file EnergyLossSimulator.h.

37 { return deltaP; }

References deltaP.

Referenced by CalorimetryManager::MuonMipSimulation().

◆ mostLikelyLoss()

double EnergyLossSimulator::mostLikelyLoss ( ) const

inline

Return most probable energy loss.

Definition at line 34 of file EnergyLossSimulator.h.

34 { return mostProbableLoss; }

References mostProbableLoss.

Member Data Documentation

◆ deltaP

XYZTLorentzVector EnergyLossSimulator::deltaP

private

The actual energy loss.

Definition at line 50 of file EnergyLossSimulator.h.

Referenced by compute(), and deltaMom().

◆ mostProbableLoss

double EnergyLossSimulator::mostProbableLoss

private

The most probable enery loss.

Definition at line 47 of file EnergyLossSimulator.h.

Referenced by compute(), and mostLikelyLoss().

◆ theGenerator

LandauFluctuationGenerator* EnergyLossSimulator::theGenerator

private

The Landau Fluctuation generator.

Definition at line 41 of file EnergyLossSimulator.h.

Referenced by compute(), EnergyLossSimulator(), and ~EnergyLossSimulator().

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ EnergyLossSimulator()

◆ ~EnergyLossSimulator()

Member Function Documentation

◆ compute()

◆ deltaMom()

◆ mostLikelyLoss()

Member Data Documentation

◆ deltaP

◆ mostProbableLoss

◆ theGenerator