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| Below are definitions of the structures used in the clas12 dc reconstructions.
| | [https://jeffersonlab.github.io/clas12-offline-software/ JavaDocs] |
| | __TOC__ |
| =Hits= | | =Hits= |
| [[File:DF_Hit-FittedHitUML.png|600px]]
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| ==Hit.java==
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| 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:
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| {| class="wikitable" style="text-align: left;"
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| |-
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| |Sector||Which of the six radial sectors the hit is in.||[[File:DF_Test_Image.png|thumb]]
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| |-
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| |Superlayer||Which of the six superlayers the hit is in.||
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| |-
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| |Layer||Which of the six wire plane layers within the superlayer the hit is in.||
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| |-
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| |Wire||The wire within the layer the hit is in.||
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| |-
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| |TDC||The Time-to-Digital Converter which processed the hit
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| |}
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| And some information about the interaction itself:
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| {| class="wikitable" style="text-align: left;"
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| |-
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| |ID||The hit index in the Evio column.
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| |-
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| |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]]
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| |-
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| |DoCA Error||Uncertainty in the distance of closest approach time.
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| |}
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| 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).
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| ==FittedHit.java==
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| An extension of Hit.java which is meant to be used in fitted clusters, this includes additional information:
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| {| class="wikitable" style="text-align: left;"
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| |X||X at Z in local coordinate system
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| |-
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| |XMP||X at the midplane in the sector coordinate system
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| |-
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| |Z||Z in the Sector Coordinate System
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| |-
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| |lX||X in the local coordinate system; used in hit-based fit to cluster.
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| |-
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| |lY||Y in the local coordinate system; used in hit-based fit to cluster.
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| |-
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| |Residual||Cluster line to the wire position residual
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| |-
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| |Time Residual||Cluster line to wire position time residual
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| |-
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| |Left-Right Ambiguity|| Gives a value to handle the left-right ambiguity:
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| |-1 => y-fit < 0 to the left of the wire=> <code>y=y-lr*TimeToDistance</code>
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| |-
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| |Quality Fac||?
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| |-
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| |Tracking Status||A flag which denotes the tracking status:
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| *-1 => not fit
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| *0 => hit-based tracking fit
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| *1 => time-based tracking fit.
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| |-
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| |Cluster Fit DoCA||?
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| |-
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| |Track Fit DoCA||?
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| |-
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| |Time to Distance||?
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| |-
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| |Beta||?
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| |-
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| |Associated State Vector||?
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| |-
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| |DoCA||?
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| |-
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| |B||?
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| |-
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| |lr||?
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| |-
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| |Associated Cluster ID||?
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| |-
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| |Remove Flag||?
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| |-
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| |Associated HB Track ID||?
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| |-
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| |Associated TB Track ID||?
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| |-
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| |CrossDirIntersWire||?
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| |-
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| |SignalPropagAlongWire||?
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| |-
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| |SignalPropagTimeAlongWire||?
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| |-
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| |T0||?
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| |-
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| |tFlight||?
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| |-
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| |tProp||?
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| |-
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| |tStart||?
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| |-
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| |Time||?
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| |}
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| =Clusters= | | =Clusters= |
| Clusters are groups of hits within each superlayer.
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| =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.
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|
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| =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.
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| =Tracks= | | =Tracks= |
| Extends Trajectory. A collection of state vectors which describe the position, momentum, and charge at various points in the DC.
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| =Program Flowcharts= | | =Program Flowcharts= |
| ==Overview== | | ==Overview== |
