Difference between revisions of "DF Definitions of Tracking Elements"

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(Replaced content with "[https://jeffersonlab.github.io/clas12-offline-software/ JavaDocs] __TOC__ =Hits= =Clusters= =Segments= =Crosses= =Tracks= =Program Flowcharts= ==Overview== File:DF_Reco...")
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Below are definitions of the structures used in the clas12 dc reconstructions.
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[https://jeffersonlab.github.io/clas12-offline-software/ JavaDocs]
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__TOC__
 
=Hits=
 
=Hits=
[[File:DF_Hit-FittedHitUML.png|600px]]
 
==Hit.java==
 
The basic building block of the other structures used in the reconstruction, Hits are simply a representation of a drift chamber wire interaction. It stores all of the relevant information for identifying a wire:
 
{| class="wikitable" style="text-align: left;"
 
|-
 
|Sector||Which of the six radial sectors the hit is in.||[[File:DF_Test_Image.png|thumb]]
 
|-
 
|Superlayer||Which of the six superlayers the hit is in.||
 
|-
 
|Layer||Which of the six wire plane layers within the superlayer the hit is in.||
 
|-
 
|Wire||The wire within the layer the hit is in.||
 
|-
 
|TDC||The Time-to-Digital Converter which processed the hit
 
|}
 
 
And some information about the interaction itself:
 
{| class="wikitable" style="text-align: left;"
 
|-
 
|ID||The hit index in the Evio column.
 
|-
 
|Cell Size||The size of the wire cell. The wires are arranged in hexagonal cells, but different layers have different sizes of hexagons.||[[File:DF_Test_Image.png|thumb]]
 
|-
 
|DoCA Error||Uncertainty in the distance of closest approach time.
 
|}
 
 
It should be noted that this implements the Comparable interface; that is to say the the function compareTo() has been implemented such that hits can be absolutely ordered. The ordering appears to be exactly as you would expect: Sector > SuperLayer > Layer > Wire. This allows you to call the built in sort function of ArrayLists of Hits (such as Clusters).
 
==FittedHit.java==
 
An extension of Hit.java which is meant to be used in fitted clusters, this includes additional information:
 
{| class="wikitable" style="text-align: left;"
 
|X||X at Z in local coordinate system
 
|-
 
|XMP||X at the midplane in the sector coordinate system
 
|-
 
|Z||Z in the Sector Coordinate System
 
|-
 
|lX||X in the local coordinate system; used in hit-based fit to cluster.
 
|-
 
|lY||Y in the local coordinate system; used in hit-based fit to cluster.
 
|-
 
|Residual||Cluster line to the wire position residual
 
|-
 
|Time Residual||Cluster line to wire position time residual
 
|-
 
|Left-Right Ambiguity|| Gives a value to handle the left-right ambiguity:
 
|-1 => y-fit < 0 to the left of the wire=> <code>y=y-lr*TimeToDistance</code>
 
|-
 
|Quality Fac||?
 
|-
 
|Tracking Status||A flag which denotes the tracking status:
 
*-1 => not fit
 
*0 => hit-based tracking fit
 
*1 => time-based tracking fit.
 
|-
 
|Cluster Fit DoCA||?
 
|-
 
|Track Fit DoCA||?
 
|-
 
|Time to Distance||?
 
|-
 
|Beta||?
 
|-
 
|Associated State Vector||?
 
|-
 
|DoCA||?
 
|-
 
|B||?
 
|-
 
|lr||?
 
|-
 
|Associated Cluster ID||?
 
|-
 
|Remove Flag||?
 
|-
 
|Associated HB Track ID||?
 
|-
 
|Associated TB Track ID||?
 
|-
 
|CrossDirIntersWire||?
 
|-
 
|SignalPropagAlongWire||?
 
|-
 
|SignalPropagTimeAlongWire||?
 
|-
 
|T0||?
 
|-
 
|tFlight||?
 
|-
 
|tProp||?
 
|-
 
|tStart||?
 
|-
 
|Time||?
 
|}
 
 
 
=Clusters=
 
=Clusters=
Clusters are groups of hits within each superlayer.
 
 
 
=Segments=
 
=Segments=
A type of FittedCluster that has been pruned of bad hits. Note that in the code this isn't reflected via inheritance, it is simply comment this way.
 
 
 
=Crosses=
 
=Crosses=
Crosses are used to find tracks. They are implemented as an ArrayList of Segments. The cross "object" is simply a point in 3D space and a direction unit vector.
 
 
 
=Tracks=
 
=Tracks=
Extends Trajectory. A collection of state vectors which describe the position, momentum, and charge at various points in the DC.
 
 
 
=Program Flowcharts=
 
=Program Flowcharts=
 
==Overview==
 
==Overview==

Revision as of 19:10, 20 June 2018

JavaDocs

Hits

Clusters

Segments

Crosses

Tracks

Program Flowcharts

Overview

DF RecoFlowChart.png

DCHB Process Event

DF DCHBProcessEvent.png

DCTB Process Event

DF DCTBProcessEvent.png

Main Page

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