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#include <EnergyLossUpdator.h>
Public Member Functions | |
| virtual EnergyLossUpdator * | clone () const |
| EnergyLossUpdator (double mass) | |
Private Member Functions | |
| virtual void | compute (const TrajectoryStateOnSurface &, const PropagationDirection) const dso_internal |
| void | computeBetheBloch (const LocalVector &, const MediumProperties &) const dso_internal |
| void | computeElectrons (const LocalVector &, const MediumProperties &, const PropagationDirection) const dso_internal |
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.
| EnergyLossUpdator::EnergyLossUpdator | ( | double | mass | ) | [inline] |
Definition at line 28 of file EnergyLossUpdator.h.
Referenced by clone().
:
MaterialEffectsUpdator(mass) {}
| virtual EnergyLossUpdator* EnergyLossUpdator::clone | ( | void | ) | const [inline, virtual] |
Implements MaterialEffectsUpdator.
Definition at line 23 of file EnergyLossUpdator.h.
References EnergyLossUpdator().
{
return new EnergyLossUpdator(*this);
}
| void EnergyLossUpdator::compute | ( | const TrajectoryStateOnSurface & | TSoS, |
| const PropagationDirection | propDir | ||
| ) | const [private, virtual] |
Implements MaterialEffectsUpdator.
Definition at line 9 of file EnergyLossUpdator.cc.
References alongMomentum, computeBetheBloch(), computeElectrons(), TrajectoryStateOnSurface::localMomentum(), MaterialEffectsUpdator::mass(), Surface::mediumProperties(), TrajectoryStateOnSurface::surface(), MaterialEffectsUpdator::theDeltaCov, and MaterialEffectsUpdator::theDeltaP.
{
//
// Get surface
//
const Surface& surface = TSoS.surface();
//
// Initialise dP and the update to the covariance matrix
//
theDeltaP = 0.;
theDeltaCov(0,0) = 0.;
//
// Now get information on medium
//
if (surface.mediumProperties()) {
//
// Bethe-Bloch
//
if ( mass()>0.001 )
computeBetheBloch(TSoS.localMomentum(),*surface.mediumProperties());
//
// Special treatment for electrons (currently rather crude
// distinction using mass)
//
else
computeElectrons(TSoS.localMomentum(),*surface.mediumProperties(),
propDir);
if (propDir != alongMomentum) theDeltaP *= -1.;
}
}
| void EnergyLossUpdator::computeBetheBloch | ( | const LocalVector & | localP, |
| const MediumProperties & | materialConstants | ||
| ) | const [private] |
Definition at line 44 of file EnergyLossUpdator.cc.
References beta, funct::log(), m, PV3DBase< T, PVType, FrameType >::mag(), MaterialEffectsUpdator::mass(), AlCaHLTBitMon_ParallelJobs::p, mathSSE::sqrt(), MaterialEffectsUpdator::theDeltaCov, MaterialEffectsUpdator::theDeltaP, MediumProperties::xi(), and PV3DBase< T, PVType, FrameType >::z().
Referenced by compute().
{
//
// calculate absolute momentum and correction to path length from angle
// of incidence
//
double p = localP.mag();
double xf = fabs(p/localP.z());
// constants
const double m = mass(); // use mass hypothesis from constructor
const double emass = 0.511e-3;
const double poti = 16.e-9 * 10.75; // = 16 eV * Z**0.9, for Si Z=14
const double eplasma = 28.816e-9 * sqrt(2.33*0.498); // 28.816 eV * sqrt(rho*(Z/A)) for Si
const double delta0 = 2*log(eplasma/poti) - 1.;
// calculate general physics things
double e = sqrt(p*p + m*m);
double beta = p/e;
double gamma = e/m;
double eta2 = beta*gamma; eta2 *= eta2;
// double lnEta2 = log(eta2);
double ratio = emass/m;
double emax = 2.*emass*eta2/(1. + 2.*ratio*gamma + ratio*ratio);
// double delta = delta0 + lnEta2;
// calculate the mean and sigma of energy loss
// xi = d[g/cm2] * 0.307075MeV/(g/cm2) * Z/A * 1/2
double xi = materialConstants.xi()*xf; xi /= (beta*beta);
// double dEdx = xi*(log(2.*emass*eta2*emax/(poti*poti)) - 2.*(beta*beta));
//double dEdx = xi*(log(2.*emass*emax/(poti*poti))+lnEta2 - 2.*(beta*beta) - delta);
double dEdx = xi*(log(2.*emass*emax/(poti*poti)) - 2.*(beta*beta) - delta0);
double dEdx2 = xi*emax*(1.-0.5*(beta*beta));
double dP = dEdx/beta;
double sigp2 = dEdx2*e*e/(p*p*p*p*p*p);
theDeltaP += -dP;
theDeltaCov(0,0) += sigp2;
}
| void EnergyLossUpdator::computeElectrons | ( | const LocalVector & | localP, |
| const MediumProperties & | materialConstants, | ||
| const PropagationDirection | propDir | ||
| ) | const [private] |
Definition at line 88 of file EnergyLossUpdator.cc.
References funct::exp(), f, funct::log(), PV3DBase< T, PVType, FrameType >::mag(), oppositeToMomentum, AlCaHLTBitMon_ParallelJobs::p, MediumProperties::radLen(), MaterialEffectsUpdator::theDeltaCov, MaterialEffectsUpdator::theDeltaP, PV3DBase< T, PVType, FrameType >::z(), and z.
Referenced by compute().
{
//
// calculate absolute momentum and correction to path length from angle
// of incidence
//
double p = localP.mag();
double normalisedPath = fabs(p/localP.z())*materialConstants.radLen();
//
// Energy loss and variance according to Bethe and Heitler, see also
// Comp. Phys. Comm. 79 (1994) 157.
//
double z = exp(-normalisedPath);
double varz = exp(-normalisedPath*log(3.)/log(2.))-
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!!!
//
theDeltaP += -p*(1/z-1);
theDeltaCov(0,0) += varz/(p*p);
}
else {
//
// for forward propagation: calculate in p (linear in 1/z=p_inside/p_outside),
// then convert sig(p) to sig(1/p).
//
theDeltaP += p*(z-1);
// double f = 1/p/z/z;
// patch to ensure consistency between for- and backward propagation
double f = 1./(p*z);
theDeltaCov(0,0) += f*f*varz;
}
}
1.7.3