Cosmic TF Algorithm

Goal of the page

The user is expected to be able to use the cosmic track finder for cosmic ray reconstruction and to adapt it to several geometries and detector conditions.



The Cosmic Track Finder is a tracking algorithm dedicated to the single cosmic muon reconstruction. The main difference wrt the KF is on the pattern recognition, indeed it is based on the hypothesis that muons come from the top along vertical direction. This simple hit selection allows to reconstruct muons in different geometry configurations when just a portion of the tracker modules was switched on or when dedicated geometry was used It has been successfully used during the MTCC and at the TIF

Usage of the algorithm

The cosmic track finder is based on two modules:

The Cosmic Seed Generator that creates the first hit pair or triplet of hits:

cosmicseedfinder = cms.EDFilter("CosmicSeedGenerator",
    stereorecHits = cms.InputTag("siStripMatchedRecHits","stereoRecHit"),
    originZPosition = cms.double(0.0),
    GeometricStructure = cms.untracked.string('STANDARD'), ##other choice: TIBD+

    matchedRecHits = cms.InputTag("siStripMatchedRecHits","matchedRecHit"),
    MaxNumberOfCosmicClusters = cms.uint32(300),
    maxSeeds = cms.int32(10000),
    SeedPt = cms.double(5.0),
    HitsForSeeds = cms.untracked.string('pairs'),
    TTRHBuilder = cms.string('WithTrackAngle'),
    ptMin = cms.double(0.9),
    rphirecHits = cms.InputTag("siStripMatchedRecHits","rphiRecHit"),
    doClusterCheck = cms.bool(True),
    originRadius = cms.double(150.0),
    ClusterCollectionLabel = cms.InputTag("siStripClusters"),
    originHalfLength = cms.double(90.0),
    PositiveYOnly = cms.bool(False),
    NegativeYOnly = cms.bool(False)  

The Cosmic Track Finder that creates the track candidates associated to the cosmic rays:
cosmictrackfinder = cms.EDFilter("CosmicTrackFinder",
    stereorecHits = cms.InputTag("siStripMatchedRecHits","stereoRecHit"),  #hit collection
    HitProducer = cms.string('siStripRecHits'), 
    pixelRecHits = cms.InputTag("siPixelRecHits"), #hit collection
    matchedRecHits = cms.InputTag("siStripMatchedRecHits","matchedRecHit"), #hit collection
    MinHits = cms.int32(4), #min number of hits for the track
    Chi2Cut = cms.double(30.0),  #max value
    TTRHBuilder = cms.string('WithTrackAngle'), 
    rphirecHits = cms.InputTag("siStripMatchedRecHits","rphiRecHit"), #hit collection
    debug = cms.untracked.bool(True),
    GeometricStructure = cms.untracked.string('MTCC'),  #structure of the tracker
    cosmicSeeds = cms.InputTag("cosmicseedfinder") #seed collection

Software architecture

The architecture of the Cosmic Track Finder reflects the whole tracking architecture. There are three phases: seeding(in RecoTracker/SpecialSeedGenerators) , pattern recognition (in RecoTracker/SingleTrackPattern) and fitting


Review status

Reviewer/Editor and Date (copy from screen) Comments
KatiLassilaPerini - 29 Jan 2008 created template page

Responsible: ResponsibleIndividual
Last reviewed by: Most recent reviewer

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Topic revision: r2 - 2009-04-22 - MichelePioppi
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