EnergyLossUpdator Class Reference

#include <EnergyLossUpdator.h>

Inheritance diagram for EnergyLossUpdator:

Public Member Functions
EnergyLossUpdator *	clone () const override
void	compute (const TrajectoryStateOnSurface &, const PropagationDirection, Effect &effect) const override
	EnergyLossUpdator (float mass)
Public Member Functions inherited from MaterialEffectsUpdator
float	mass () const
	MaterialEffectsUpdator (float mass)
virtual TrajectoryStateOnSurface	updateState (const TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const
virtual bool	updateStateInPlace (TrajectoryStateOnSurface &TSoS, const PropagationDirection propDir) const
virtual	~MaterialEffectsUpdator ()

Private Member Functions
void	computeBetheBloch (const LocalVector &, const MediumProperties &, Effect &effect) const
void	computeElectrons (const LocalVector &, const MediumProperties &, const PropagationDirection, Effect &effect) const

Additional Inherited Members
Public Types inherited from MaterialEffectsUpdator
typedef materialEffect::Covariance	Covariance
typedef materialEffect::CovIndex	CovIndex
typedef materialEffect::Effect	Effect

Detailed Description

Energy loss according to Bethe-Bloch + special treatment for electrons. Adds effects from energy loss according to Bethe-Bloch formula without density effect. Assumes silicon as material. For electrons energy loss due to radiation added according to formulae by Bethe & Heitler. Ported from ORCA.

Definition at line 20 of file EnergyLossUpdator.h.

Constructor & Destructor Documentation

EnergyLossUpdator()

EnergyLossUpdator::EnergyLossUpdator ( float  mass )

inline

Definition at line 25 of file EnergyLossUpdator.h.

Referenced by clone().

: MaterialEffectsUpdator(mass) {}

Member Function Documentation

clone()

EnergyLossUpdator* EnergyLossUpdator::clone ( void  ) const

inlineoverridevirtual

Implements MaterialEffectsUpdator.

Definition at line 22 of file EnergyLossUpdator.h.

References EnergyLossUpdator().

{ return new EnergyLossUpdator(*this); }

compute()

void EnergyLossUpdator::compute ( const TrajectoryStateOnSurface &  TSoS, const PropagationDirection  propDir, Effect &  effect  ) const

overridevirtual

Implements MaterialEffectsUpdator.

Definition at line 17 of file EnergyLossUpdator.cc.

References alongMomentum, computeBetheBloch(), computeElectrons(), materialEffect::Effect::deltaP, MediumProperties::isValid(), TrajectoryStateOnSurface::localMomentum(), MaterialEffectsUpdator::mass(), Surface::mediumProperties(), and TrajectoryStateOnSurface::surface().

Referenced by CombinedMaterialEffectsUpdator::compute().

                                                      {
  //
  // Get surface
  //
  const Surface& surface = TSoS.surface();
  //
  //
  // Now get information on medium
  //
  if (surface.mediumProperties().isValid()) {
    //
    // Bethe-Bloch
    //
    if (mass() > 0.001)
      computeBetheBloch(TSoS.localMomentum(), surface.mediumProperties(), effect);
    //
    // Special treatment for electrons (currently rather crude
    // distinction using mass)
    //
    else
      computeElectrons(TSoS.localMomentum(), surface.mediumProperties(), propDir, effect);
    if (propDir != alongMomentum)
      effect.deltaP *= -1.;
  }
}

computeBetheBloch()

void EnergyLossUpdator::computeBetheBloch ( const LocalVector &  localP, const MediumProperties &  materialConstants, Effect &  effect  ) const

private

Definition at line 47 of file EnergyLossUpdator.cc.

References funct::abs(), plot_hgcal_utils::dEdx, materialEffect::Effect::deltaCov, materialEffect::Effect::deltaP, MillePedeFileConverter_cfg::e, materialEffect::elos, HLT_2022v11_cff::eta2, dqm-mbProfile::log, callgraph::m2, PV3DBase< T, PVType, FrameType >::mag2(), MaterialEffectsUpdator::mass(), SiStripOfflineCRack_cfg::p2, mathSSE::sqrt(), MediumProperties::xi(), protons_cff::xi, and PV3DBase< T, PVType, FrameType >::z().

Referenced by compute().

                                                                {
  //
  // calculate absolute momentum and correction to path length from angle
  // of incidence
  //

  typedef float Float;

  Float p2 = localP.mag2();
  Float xf = std::abs(std::sqrt(p2) / localP.z());

  // constants
  const Float m2 = mass() * mass();  // use mass hypothesis from constructor

  constexpr Float emass = 0.511e-3;
  constexpr Float poti = 16.e-9 * 10.75;                 // = 16 eV * Z**0.9, for Si Z=14
  const Float eplasma = 28.816e-9 * sqrt(2.33 * 0.498);  // 28.816 eV * sqrt(rho*(Z/A)) for Si
  const Float delta0 = 2 * log(eplasma / poti) - 1.;

  // calculate general physics things
  Float im2 = Float(1.) / m2;
  Float e2 = p2 + m2;
  Float e = std::sqrt(e2);
  Float beta2 = p2 / e2;
  Float eta2 = p2 * im2;
  Float ratio2 = (emass * emass) * im2;
  Float emax = Float(2.) * emass * eta2 / (Float(1.) + Float(2.) * emass * e * im2 + ratio2);

  Float xi = materialConstants.xi() * xf;
  xi /= beta2;

  Float dEdx = xi * (unsafe_logf<2>(Float(2.) * emass * emax / (poti * poti)) - Float(2.) * (beta2)-delta0);

  Float dEdx2 = xi * emax * (Float(1.) - Float(0.5) * beta2);
  Float dP = dEdx / std::sqrt(beta2);
  Float sigp2 = dEdx2 / (beta2 * p2 * p2);
  effect.deltaP += -dP;
  using namespace materialEffect;
  effect.deltaCov[elos] += sigp2;

  // std::cout << "pion new " <<  theDeltaP << " " << theDeltaCov(0,0) << std::endl;
  // oldComputeBetheBloch (localP, materialConstants, mass());
}

computeElectrons()

void EnergyLossUpdator::computeElectrons ( const LocalVector &  localP, const MediumProperties &  materialConstants, const PropagationDirection  propDir, Effect &  effect  ) const

private

Definition at line 95 of file EnergyLossUpdator.cc.

References funct::abs(), materialEffect::Effect::deltaCov, materialEffect::Effect::deltaP, materialEffect::elos, DeadROC_duringRun::f2, dqm-mbProfile::log, PV3DBase< T, PVType, FrameType >::mag2(), oppositeToMomentum, AlCaHLTBitMon_ParallelJobs::p, SiStripOfflineCRack_cfg::p2, MediumProperties::radLen(), mathSSE::sqrt(), z, and PV3DBase< T, PVType, FrameType >::z().

Referenced by compute().

                                                               {
  //
  // calculate absolute momentum and correction to path length from angle
  // of incidence
  //
  float p2 = localP.mag2();
  float p = std::sqrt(p2);
  float normalisedPath = std::abs(p / localP.z()) * materialConstants.radLen();
  //
  // Energy loss and variance according to Bethe and Heitler, see also
  // Comp. Phys. Comm. 79 (1994) 157.
  //
  const float l3ol2 = std::log(3.) / std::log(2.);
  float z = unsafe_expf<3>(-normalisedPath);
  float varz = unsafe_expf<3>(-normalisedPath * l3ol2) - z * z;
  // exp(-2*normalisedPath);

  if (propDir == oppositeToMomentum) {
    //
    // for backward propagation: delta(1/p) is linear in z=p_outside/p_inside
    // convert to obtain equivalent delta(p). Sign of deltaP is corrected
    // in method compute -> deltaP<0 at this place!!!
    //
    effect.deltaP += -p * (1.f / z - 1.f);
    using namespace materialEffect;
    effect.deltaCov[elos] += varz / p2;
  } else {
    //
    // for forward propagation: calculate in p (linear in 1/z=p_inside/p_outside),
    // then convert sig(p) to sig(1/p).
    //
    effect.deltaP += p * (z - 1.f);
    //    float f = 1/p/z/z;
    // patch to ensure consistency between for- and backward propagation
    float f2 = 1.f / (p2 * z * z);
    using namespace materialEffect;
    effect.deltaCov[elos] += f2 * varz;
  }

  // std::cout << "electron new " <<  theDeltaP << " " << theDeltaCov(0,0) << std::endl;
  // oldComputeElectrons (localP, materialConstants, propDir);
}