Garfield::TrackElectron Class Reference

Ionization calculation based on MIP program (S. Biagi). More...

#include <TrackElectron.hh>

Inheritance diagram for Garfield::TrackElectron:

Public Member Functions
	TrackElectron ()
virtual	~TrackElectron ()
virtual void	SetParticle (const std::string &particle)
virtual bool	NewTrack (const double x0, const double y0, const double z0, const double t0, const double dx0, const double dy0, const double dz0)
virtual bool	GetCluster (double &xcls, double &ycls, double &zcls, double &tcls, int &ncls, double &ecls, double &extra)
virtual double	GetClusterDensity ()
virtual double	GetStoppingPower ()
	Get the stopping power (mean energy loss [eV] per cm).
Public Member Functions inherited from Garfield::Track
	Track ()
	Constructor.
virtual	~Track ()
	Destructor.
virtual void	SetParticle (const std::string &part)
void	SetEnergy (const double e)
	Set the particle energy.
void	SetBetaGamma (const double bg)
	Set the relative momentum of the particle.
void	SetBeta (const double beta)
	Set the speed ( ) of the particle.
void	SetGamma (const double gamma)
	Set the Lorentz factor of the particle.
void	SetMomentum (const double p)
	Set the particle momentum.
void	SetKineticEnergy (const double ekin)
	Set the kinetic energy of the particle.
double	GetEnergy () const
	Return the particle energy.
double	GetBetaGamma () const
	Return the of the projectile.
double	GetBeta () const
	Return the speed ( ) of the projectile.
double	GetGamma () const
	Return the Lorentz factor of the projectile.
double	GetMomentum () const
	Return the particle momentum.
double	GetKineticEnergy () const
	Return the kinetic energy of the projectile.
double	GetCharge () const
	Get the charge of the projectile.
double	GetMass () const
	Get the mass [eV / c2] of the projectile.
void	SetSensor (Sensor *s)
	Set the sensor through which to transport the particle.
virtual bool	NewTrack (const double x0, const double y0, const double z0, const double t0, const double dx0, const double dy0, const double dz0)=0
virtual bool	GetCluster (double &xcls, double &ycls, double &zcls, double &tcls, int &n, double &e, double &extra)=0
virtual double	GetClusterDensity ()
virtual double	GetStoppingPower ()
	Get the stopping power (mean energy loss [eV] per cm).
void	EnablePlotting (ViewDrift *viewer)
	Switch on plotting.
void	DisablePlotting ()
	Switch off plotting.
void	EnableDebugging ()
	Switch on debugging messages.
void	DisableDebugging ()
	Switch off debugging messages.

Additional Inherited Members
Protected Member Functions inherited from Garfield::Track
void	PlotNewTrack (const double x0, const double y0, const double z0)
void	PlotCluster (const double x0, const double y0, const double z0)
Protected Attributes inherited from Garfield::Track
std::string	m_className = "Track"
double	m_q = -1.
int	m_spin = 1
double	m_mass
double	m_energy = 0.
double	m_beta2
bool	m_isElectron = false
std::string	m_particleName = "mu-"
Sensor *	m_sensor = nullptr
bool	m_isChanged = true
ViewDrift *	m_viewer = nullptr
bool	m_debug = false
size_t	m_plotId = 0

Detailed Description

Ionization calculation based on MIP program (S. Biagi).

Definition at line 13 of file TrackElectron.hh.

Constructor & Destructor Documentation

TrackElectron()

Garfield::TrackElectron::TrackElectron

(

)

Definition at line 12 of file TrackElectron.cc.

                             : Track() {
  m_className = "TrackElectron";
 
  // Setup the particle properties.
  m_q = -1;
  m_spin = 1;
  m_mass = ElectronMass;
  m_isElectron = true;
  SetBetaGamma(3.);
  m_particleName = "electron";
}

~TrackElectron()

virtual Garfield::TrackElectron::~TrackElectron ( )

inlinevirtual

Definition at line 18 of file TrackElectron.hh.

{}

Member Function Documentation

GetCluster()

bool Garfield::TrackElectron::GetCluster ( double &  xcls, double &  ycls, double &  zcls, double &  tcls, int &  n, double &  e, double &  extra  )

virtual

Get the next "cluster" (ionising collision of the charged particle).

Parameters

xcls,ycls,zcls	coordinates of the collision
tcls	time of the collision
n	number of electrons produced
e	deposited energy
extra	additional information (not always implemented)

Implements Garfield::Track.

Definition at line 99 of file TrackElectron.cc.

                                              {
  edep = extra = 0.;
  ncls = 0;
 
  m_electrons.clear();
 
  if (!m_ready) {
    std::cerr << m_className << "::GetCluster:\n"
              << "    Track not initialized. Call NewTrack first.\n";
    return false;
  }
 
  // Draw a step length and propagate the electron.
  const double d = -m_mfp * log(RndmUniformPos());
  m_x += d * m_dx;
  m_y += d * m_dy;
  m_z += d * m_dz;
  m_t += d / (sqrt(m_beta2) * SpeedOfLight);
 
  if (!m_sensor->IsInArea(m_x, m_y, m_z)) {
    m_ready = false;
    return false;
  }
 
  Medium* medium = nullptr;
  if (!m_sensor->GetMedium(m_x, m_y, m_z, medium)) {
    m_ready = false;
    return false;
  }
 
  if (medium->GetName() != m_mediumName ||
      medium->GetNumberDensity() != m_mediumDensity || !medium->IsIonisable()) {
    m_ready = false;
    return false;
  }
 
  xcls = m_x;
  ycls = m_y;
  zcls = m_z;
  tcls = m_t;
  const double r = RndmUniform();
  int iComponent = 0;
  const int nComponents = m_components.size();
  for (int i = 0; i < nComponents; ++i) {
    if (r <= RndmUniform()) {
      iComponent = i;
      break;
    }
  }
 
  // Sample secondary electron energy according to
  // Opal-Beaty-Peterson splitting function.
  const double e0 = ElectronMass * (sqrt(1. / (1. - m_beta2)) - 1.);
  double esec =
      m_components[iComponent].wSplit *
      tan(RndmUniform() * atan((e0 - m_components[iComponent].ethr) /
                               (2. * m_components[iComponent].wSplit)));
  esec = m_components[iComponent].wSplit *
         pow(esec / m_components[iComponent].wSplit, 0.9524);
  m_electrons.resize(1);
  m_electrons[0].energy = esec;
  m_electrons[0].x = xcls;
  m_electrons[0].y = ycls;
  m_electrons[0].z = zcls;
 
  ncls = 1;
  edep = esec;
 
  return true;
}

GetClusterDensity()

double Garfield::TrackElectron::GetClusterDensity ( )

virtual

Get the cluster density (number of ionizing collisions per cm or inverse mean free path for ionization).

Reimplemented from Garfield::Track.

Definition at line 172 of file TrackElectron.cc.

                                        {
  if (!m_ready) {
    std::cerr << m_className << "::GetClusterDensity:\n";
    std::cerr << "    Track has not been initialized.\n";
    return 0.;
  }
 
  if (m_mfp <= 0.) {
    std::cerr << m_className << "::GetClusterDensity:\n";
    std::cerr << "    Mean free path is not available.\n";
    return 0.;
  }
 
  return 1. / m_mfp;
}

GetStoppingPower()

double Garfield::TrackElectron::GetStoppingPower ( )

virtual

Get the stopping power (mean energy loss [eV] per cm).

Reimplemented from Garfield::Track.

Definition at line 188 of file TrackElectron.cc.

                                       {
  if (!m_ready) {
    std::cerr << m_className << "::GetStoppingPower:\n";
    std::cerr << "    Track has not been initialised.\n";
    return 0.;
  }
 
  constexpr double prefactor =
      4 * Pi * HbarC * HbarC / (ElectronMass * ElectronMass);
  const double lnBg2 = log(m_beta2 / (1. - m_beta2));
 
  double dedx = 0.;
  // Primary energy
  const double e0 = ElectronMass * (sqrt(1. / (1. - m_beta2)) - 1.);
  const int nComponents = m_components.size();
  for (int i = nComponents; i--;) {
    // Calculate the mean number of clusters per cm.
    const double cmean =
        m_mediumDensity * m_components[i].fraction * (prefactor / m_beta2) *
        (m_components[i].m2Ion * (lnBg2 - m_beta2) + m_components[i].cIon);
    const double ew =
        (e0 - m_components[i].ethr) / (2 * m_components[i].wSplit);
    // Calculate the mean secondary electron energy.
    const double emean =
        (m_components[i].wSplit / (2 * atan(ew))) * log(1. + ew * ew);
    dedx += cmean * emean;
  }
 
  return dedx;
}

NewTrack()

bool Garfield::TrackElectron::NewTrack ( const double  x0, const double  y0, const double  z0, const double  t0, const double  dx0, const double  dy0, const double  dz0  )

virtual

Calculate a new track starting from (x0, y0, z0) at time t0 in direction (dx0, dy0, dz0).

Implements Garfield::Track.

Definition at line 30 of file TrackElectron.cc.

                                                                 {
  m_ready = false;
 
  // Make sure the sensor has been set.
  if (!m_sensor) {
    std::cerr << m_className << "::NewTrack: Sensor is not defined.\n";
    return false;
  }
 
  // Get the medium at this location and check if it is "ionisable".
  Medium* medium = nullptr;
  if (!m_sensor->GetMedium(x0, y0, z0, medium)) {
    std::cerr << m_className << "::NewTrack:\n";
    std::cerr << "    No medium at initial position.\n";
    return false;
  }
  if (!medium->IsIonisable()) {
    std::cerr << m_className << "::NewTrack:\n";
    std::cerr << "    Medium at initial position is not ionisable.\n";
    return false;
  }
 
  // Check if the medium is a gas.
  if (!medium->IsGas()) {
    std::cerr << m_className << "::NewTrack:\n";
    std::cerr << "    Medium at initial position is not a gas.\n";
    return false;
  }
 
  if (!SetupGas(medium)) {
    std::cerr << m_className << "::NewTrack:\n";
    std::cerr << "    Properties of medium " << medium->GetName()
              << " are not available.\n";
    return false;
  }
 
  if (!UpdateCrossSection()) {
    std::cerr << m_className << "::NewTrack:\n";
    std::cerr << "    Cross-sections could not be calculated.\n";
    return false;
  }
 
  m_mediumName = medium->GetName();
 
  m_x = x0;
  m_y = y0;
  m_z = z0;
  m_t = t0;
  const double dd = sqrt(dx0 * dx0 + dy0 * dy0 + dz0 * dz0);
  if (dd < Small) {
    if (m_debug) {
      std::cout << m_className << "::NewTrack:\n";
      std::cout << "    Direction vector has zero norm.\n";
      std::cout << "    Initial direction is randomized.\n";
    }
    RndmDirection(m_dx, m_dy, m_dz);
  } else {
    // Normalize the direction vector.
    m_dx = dx0 / dd;
    m_dy = dy0 / dd;
    m_dz = dz0 / dd;
  }
 
  m_ready = true;
  return true;
}

SetParticle()

void Garfield::TrackElectron::SetParticle ( const std::string &  part )

virtual

Set the type of charged particle.

• electron,e-
• positron,e+
• muon,mu-
• mu+
• pion,pi-
• pi+
• kaon,K-
• K+
• proton,p
• anti-proton,p-bar
• deuteron,d
• alpha

Reimplemented from Garfield::Track.

Definition at line 24 of file TrackElectron.cc.

                                                         {
  if (particle != "electron" && particle != "e" && particle != "e-") {
    std::cerr << m_className << "::SetParticle: Only electrons are allowed.\n";
  }
}

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

• TrackElectron.hh
• TrackElectron.cc