DriftLengthEstimator Struct Reference

Helper construct implementing the (re)estimation of the drift length for various hit objects. More...

#include <DriftLengthEstimator.h>

Public Member Functions
void	exposeParameters (ModuleParamList *moduleParamList, const std::string &prefix)
	Add the parameters of the estimator to the module.
double	updateDriftLength (TrackingUtilities::CDCRecoHit2D &recoHit2D)
	Update the drift length of the reconstructed hit in place.
double	updateDriftLength (TrackingUtilities::CDCRecoHit3D &recoHit3D, double tanLambda)
	Update the drift length of the reconstructed hit in place.
void	updateDriftLength (TrackingUtilities::CDCFacet &facet)
	Re-estimate the drift length of all three contained drift circles.
void	updateDriftLength (TrackingUtilities::CDCSegment2D &segment)
	Update the drift length of the contained reconstructed hit in place.
void	updateDriftLength (TrackingUtilities::CDCSegment3D &segment, double tanLambda)
	Update the drift length of the contained reconstructed hit in place.
void	updateDriftLength (TrackingUtilities::CDCTrack &track, double tanLambda)
	Update the drift length of the contained reconstructed hit in place.

Public Attributes
bool	m_param_useAlphaInDriftLength = true
	Parameter : Switch to serve the alpha angle to the drift length translator.
double	m_param_tofMassScale = NAN
	Parameter : Mass to estimate the velocity in the flight time to the hit.

Detailed Description

Helper construct implementing the (re)estimation of the drift length for various hit objects.

Definition at line 38 of file DriftLengthEstimator.h.

Member Function Documentation

exposeParameters()

void exposeParameters	(	ModuleParamList *	moduleParamList,
		const std::string &	prefix )

Add the parameters of the estimator to the module.

Definition at line 49 of file DriftLengthEstimator.cc.

{
  moduleParamList->addParameter(prefixed(prefix, "useAlphaInDriftLength"),
                                m_param_useAlphaInDriftLength,
                                "Switch to serve the alpha angle to the drift length translator",
                                m_param_useAlphaInDriftLength);
 
  moduleParamList->addParameter(prefixed(prefix, "tofMassScale"),
                                m_param_tofMassScale,
                                "Mass to estimate the velocity in the flight time to the hit",
                                m_param_tofMassScale);
}

updateDriftLength() [1/6]

void updateDriftLength

(

TrackingUtilities::CDCFacet &

facet

)

Re-estimate the drift length of all three contained drift circles.

Using the additional flight direction information the accuracy of the drift length can be increased a lot helping the filters following this step

Definition at line 93 of file DriftLengthEstimator.cc.

{
  CDC::RealisticTDCCountTranslator tdcCountTranslator;
 
  const UncertainParameterLine2D& line = facet.getFitLine();
  ROOT::Math::XYVector flightDirection = line->tangential();
  ROOT::Math::XYVector centralPos2D = line->closest(facet.getMiddleWire().getRefPos2D());
  double alpha = ROOT::Math::VectorUtil::DeltaPhi(centralPos2D, flightDirection);
  if (not m_param_useAlphaInDriftLength) {
    alpha = 0;
  }
 
  auto doUpdate = [&](CDCRLWireHit & rlWireHit, ROOT::Math::XYVector recoPos2D) {
    const CDCWire& wire = rlWireHit.getWire();
    const CDCHit* hit = rlWireHit.getWireHit().getHit();
    const bool rl = rlWireHit.getRLInfo() == ERightLeft::c_Right;
    const double beta = 1;
    double flightTimeEstimate = FlightTimeEstimator::instance().getFlightTime2D(recoPos2D, alpha, beta);
    double driftLength = tdcCountTranslator.getDriftLength(hit->getTDCCount(),
                                                           wire.getWireID(),
                                                           flightTimeEstimate,
                                                           rl,
                                                           wire.getRefZ(),
                                                           alpha);
    rlWireHit.setRefDriftLength(driftLength);
  };
 
  doUpdate(facet.getStartRLWireHit(), facet.getStartRecoPos2D());
  doUpdate(facet.getMiddleRLWireHit(), facet.getMiddleRecoPos2D());
  doUpdate(facet.getEndRLWireHit(), facet.getEndRecoPos2D());
 
  // More accurate implementation
  // double startDriftLength = updateDriftLength(facet.getStartRecoHit2D());
  // facet.getStartRLWireHit().setRefDriftLength(startDriftLength);
 
  // double middleDriftLength = updateDriftLength(facet.getMiddleRecoHit2D());
  // facet.getMiddleRLWireHit().setRefDriftLength(middleDriftLength);
 
  // double endDriftLength = updateDriftLength(facet.getEndRecoHit2D());
  // facet.getEndRLWireHit().setRefDriftLength(endDriftLength);
}

updateDriftLength() [2/6]

double updateDriftLength

(

TrackingUtilities::CDCRecoHit2D &

recoHit2D

)

Update the drift length of the reconstructed hit in place.

Definition at line 62 of file DriftLengthEstimator.cc.

{
  CDC::RealisticTDCCountTranslator tdcCountTranslator;
 
  ROOT::Math::XYVector flightDirection = recoHit2D.getFlightDirection2D();
  ROOT::Math::XYVector recoPos2D = recoHit2D.getRecoPos2D();
  double alpha = ROOT::Math::VectorUtil::DeltaPhi(recoPos2D, flightDirection);
  const double beta = 1;
  double flightTimeEstimate = FlightTimeEstimator::instance().getFlightTime2D(recoPos2D, alpha, beta);
 
  const CDCWire& wire = recoHit2D.getWire();
  const CDCHit* hit = recoHit2D.getWireHit().getHit();
  const bool rl = recoHit2D.getRLInfo() == ERightLeft::c_Right;
 
  if (not m_param_useAlphaInDriftLength) {
    alpha = 0;
  }
 
  double driftLength = tdcCountTranslator.getDriftLength(hit->getTDCCount(),
                                                         wire.getWireID(),
                                                         flightTimeEstimate,
                                                         rl,
                                                         wire.getRefZ(),
                                                         alpha);
  if (driftLength > -2 and driftLength < 16) {
    bool snapRecoPos = true;
    recoHit2D.setRefDriftLength(driftLength, snapRecoPos);
  }
  return driftLength;
}

updateDriftLength() [3/6]

double updateDriftLength	(	TrackingUtilities::CDCRecoHit3D &	recoHit3D,
		double	tanLambda )

Update the drift length of the reconstructed hit in place.

Definition at line 142 of file DriftLengthEstimator.cc.

{
  CDC::RealisticTDCCountTranslator tdcCountTranslator;
 
  ROOT::Math::XYVector flightDirection = recoHit3D.getFlightDirection2D();
  const ROOT::Math::XYZVector& recoPos3D = recoHit3D.getRecoPos3D();
  const ROOT::Math::XYVector& recoPos2D = VectorUtil::getXYVector(recoPos3D);
  double alpha = ROOT::Math::VectorUtil::DeltaPhi(recoPos2D, flightDirection);
  const double beta = 1;
  double flightTimeEstimate = FlightTimeEstimator::instance().getFlightTime2D(recoPos2D, alpha, beta);
 
  if (std::isnan(tanLambda)) {
    tanLambda = recoPos3D.z() / recoPos3D.Rho();
  }
  const double theta = M_PI / 2 - std::atan(tanLambda);
  flightTimeEstimate *= hypot2(1, tanLambda);
 
  const CDCWire& wire = recoHit3D.getWire();
  const CDCHit* hit = recoHit3D.getWireHit().getHit();
  const bool rl = recoHit3D.getRLInfo() == ERightLeft::c_Right;
  double driftLength =
    tdcCountTranslator.getDriftLength(hit->getTDCCount(),
                                      wire.getWireID(),
                                      flightTimeEstimate,
                                      rl,
                                      recoPos3D.z(),
                                      alpha,
                                      theta,
                                      hit->getADCCount());
  if (driftLength > -2 and driftLength < 16) {
    bool snapRecoPos = true;
    recoHit3D.setRecoDriftLength(driftLength, snapRecoPos);
  }
  return driftLength;
}

updateDriftLength() [4/6]

void updateDriftLength

(

TrackingUtilities::CDCSegment2D &

segment

)

Update the drift length of the contained reconstructed hit in place.

Definition at line 135 of file DriftLengthEstimator.cc.

{
  for (CDCRecoHit2D& recoHit2D : segment) {
    updateDriftLength(recoHit2D);
  }
}

updateDriftLength() [5/6]

void updateDriftLength	(	TrackingUtilities::CDCSegment3D &	segment,
		double	tanLambda )

Update the drift length of the contained reconstructed hit in place.

Definition at line 180 of file DriftLengthEstimator.cc.

{
  for (CDCRecoHit3D& recoHit3D : segment3D) {
    updateDriftLength(recoHit3D, tanLambda);
  }
}

updateDriftLength() [6/6]

void updateDriftLength	(	TrackingUtilities::CDCTrack &	track,
		double	tanLambda )

Update the drift length of the contained reconstructed hit in place.

Definition at line 188 of file DriftLengthEstimator.cc.

{
  for (CDCRecoHit3D& recoHit3D : track) {
    updateDriftLength(recoHit3D, tanLambda);
  }
}

Member Data Documentation

m_param_tofMassScale

double m_param_tofMassScale = NAN

Parameter : Mass to estimate the velocity in the flight time to the hit.

Definition at line 69 of file DriftLengthEstimator.h.

m_param_useAlphaInDriftLength

bool m_param_useAlphaInDriftLength = true

Parameter : Switch to serve the alpha angle to the drift length translator.

Definition at line 66 of file DriftLengthEstimator.h.

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

• tracking/trackFindingCDC/eventdata/utils/include/DriftLengthEstimator.h
• tracking/trackFindingCDC/eventdata/utils/src/DriftLengthEstimator.cc