DCMathSegmentMaker Package

Author

Niels.nosp@m..van.nosp@m..Eldi.nosp@m.k@ce.nosp@m.rn.ch

General description

TODO: This page needs an update - DCMath now supports calling arbitrary segment finders

The DCMathSegmentMaker is a AlgTool to find segments in MDT chambers. The algorithm performes a combinatorical search using pairs of MDT hits to create segments seeds. For each pair of MDT hits, the four tangent lines to the drift circles are calculated. Other hits in the chamber are associated with the seed lines to form segment candidates. After this stage a 2D fit is performed to the MDT drift circles to find the segment parameters.

If trigger hits are provided to the DCMathSegmentMaker, they will also be associated to segments. They are not included in the fit as their errors are much larger that those of the MDT hits so they don't add precision to the segment in most cases. The DCMathSegmentMaker calculates the number of delta electrons, out-of-time hits and holes on the segment. The information added to the segment in form of a Muon::MdtSegmentQuality. It can be used to identify fake segments.

A detailed write-up of the algorithm can be found at:

The ATLAS muon spectrometer, calibration and pattern recognition, PhD Thesis, Niels van Eldik

Usage of the DCMathSegmentMaker

The DCMathSegmentMaker inherits from the IMuonSegmentMaker interface. Clients should not directly use the DCMathSegmentMaker but rather use the package via the interface.

In your header file:

#include "MuonRecToolInterfaces,IMuonSegmentMaker.h"
 
....

within your class:

ToolHandle<Muon::IMuonSegmentMaker> m_mdtSegmentMaker;

In the cxx file:

In the constructor:

, m_mdtSegmentMaker("Muon::DCMathSegmentMaker/MySegmentMaker,this")

In initialize():

if( m_mdtSegmentMaker.retrieve().isSuccess() ){
  log<<MSG::INFO << "Retrieved " << m_mdtSegmentMaker << endmsg;
}else{
  log<<MSG::FATAL<<"Could not get " << m_mdtSegmentMaker <<endmsg;
  return StatusCode::FAILURE;
}

To use the segment maker, call one of the find-methods

m_mdtSegmentMaker->find( );

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