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#include <VolumeEnergyLossEstimator.h>
Public Member Functions | |
| virtual VolumeEnergyLossEstimator * | clone () const |
| virtual VolumeMaterialEffectsEstimate | estimate (const TrajectoryStateOnSurface refTSOS, double pathLength, const VolumeMediumProperties &medium) const |
| Creates an estimate. | |
| VolumeEnergyLossEstimator (float mass) | |
| Constructor with explicit mass hypothesis. | |
| virtual | ~VolumeEnergyLossEstimator () |
Private Member Functions | |
| void | computeBetheBloch (const LocalVector &localP, double pathLength, const VolumeMediumProperties &medium, double &deltaP, double &deltaCov00) const |
| void | computeElectrons (const LocalVector &localP, double pathLength, const VolumeMediumProperties &medium, double &deltaP, double &deltaCov00) const |
Estimation of energy loss for a finite step size in a volume.
Definition at line 15 of file VolumeEnergyLossEstimator.h.
| VolumeEnergyLossEstimator::VolumeEnergyLossEstimator | ( | float | mass | ) | [inline] |
Constructor with explicit mass hypothesis.
Definition at line 19 of file VolumeEnergyLossEstimator.h.
Referenced by clone().
| virtual VolumeEnergyLossEstimator::~VolumeEnergyLossEstimator | ( | ) | [inline, virtual] |
Definition at line 22 of file VolumeEnergyLossEstimator.h.
{}
| VolumeEnergyLossEstimator * VolumeEnergyLossEstimator::clone | ( | void | ) | const [virtual] |
Implements VolumeMaterialEffectsEstimator.
Definition at line 40 of file VolumeEnergyLossEstimator.cc.
References VolumeEnergyLossEstimator().
{
return new VolumeEnergyLossEstimator(*this);
}
| void VolumeEnergyLossEstimator::computeBetheBloch | ( | const LocalVector & | localP, |
| double | pathLength, | ||
| const VolumeMediumProperties & | medium, | ||
| double & | deltaP, | ||
| double & | deltaCov00 | ||
| ) | const [private] |
Definition at line 49 of file VolumeEnergyLossEstimator.cc.
References beta, delta, funct::log(), m, PV3DBase< T, PVType, FrameType >::mag(), VolumeMaterialEffectsEstimator::mass(), L1TEmulatorMonitor_cff::p, mathSSE::sqrt(), and VolumeMediumProperties::xi().
Referenced by estimate().
{
//
// calculate absolute momentum and correction to path length from angle
// of incidence
//
double p = localP.mag();
// constants
const double m = mass(); // use mass hypothesis from constructor
const double emass = 0.511e-3;
// FIXME: replace constants for Si
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 = pathLength * medium.xi(); 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 dEdx2 = xi*emax*(1.-beta*beta/2.);
double dP = dEdx/beta;
double sigp2 = dEdx2*e*e/(p*p*p*p*p*p);
deltaP = -dP;
deltaCov00 = sigp2;
}
| void VolumeEnergyLossEstimator::computeElectrons | ( | const LocalVector & | localP, |
| double | pathLength, | ||
| const VolumeMediumProperties & | medium, | ||
| double & | deltaP, | ||
| double & | deltaCov00 | ||
| ) | const [private] |
Definition at line 88 of file VolumeEnergyLossEstimator.cc.
References funct::exp(), f, funct::log(), PV3DBase< T, PVType, FrameType >::mag(), L1TEmulatorMonitor_cff::p, VolumeMediumProperties::x0(), and z.
Referenced by estimate().
{
//
// calculate absolute momentum and correction to path length from angle
// of incidence
//
double p = localP.mag();
double normalisedPath = pathLength / medium.x0();
//
// 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.))-
exp(-2*normalisedPath));
// FIXME: need to know propagation direction at this point
// 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!!!
// //
// deltaP = -p*(1/z-1);
// deltaCov00 = 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).
//
deltaP = p*(z-1);
// double f = 1/p/z/z;
// patch to ensure consistency between for- and backward propagation
double f = 1./p/z;
deltaCov00 += f*f*varz;
}
| VolumeMaterialEffectsEstimate VolumeEnergyLossEstimator::estimate | ( | const TrajectoryStateOnSurface | refTSOS, |
| double | pathLength, | ||
| const VolumeMediumProperties & | medium | ||
| ) | const [virtual] |
Creates an estimate.
Implements VolumeMaterialEffectsEstimator.
Definition at line 10 of file VolumeEnergyLossEstimator.cc.
References computeBetheBloch(), computeElectrons(), TrajectoryStateOnSurface::localMomentum(), and VolumeMaterialEffectsEstimator::mass().
{
//
// Initialise dP and the update to the covariance matrix
//
double deltaP = 0.;
double deltaCov00 = 0.;
//
// Bethe-Bloch
//
if ( mass()>0.001 )
computeBetheBloch(refTSOS.localMomentum(),pathLength,medium,
deltaP,deltaCov00);
//
// Special treatment for electrons (currently rather crude
// distinction using mass)
//
else
computeElectrons(refTSOS.localMomentum(),pathLength,medium,
deltaP,deltaCov00);
AlgebraicSymMatrix55 deltaCov;
deltaCov(0,0) = deltaCov00;
return VolumeMaterialEffectsEstimate(deltaP,deltaCov);
}
1.7.3