CDC Reconstruction Status

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CDC Reconstruction Status

• David Lawrence, JLab
• Nov. 10, 2006

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CDC in HDDS/HDGeant

• 23 layers of Al tubes (o.d.0.8cm t80?m)(Should
  be 100?m Kapton with 5?m Al)
• Tungsten wires, o.d.60?m(20?m Au-plated
  tungsten)
• Al support plates t2cm(0.9cm) upstream t1cm
  (0.6cm) downstream. Straws punch through plates
  (Should be filled with delrin downstream and Al
  upstream)
• 8 layers at stereo angles (/-6o)
• Length is 200cm (should be 175cm)
• Should have plexiglass on both upstream and
  downstream ends. Upstream should have some
  material to represent electronics and cables.

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CDC in HDDS/HDGeant

• Distance Of Closest Approach (DOCA) is calculated
  from midpoint of tracks entry and exit points of
  gas volume.
• tdrift calculated from DOCA point using 22?m/ns
• Truth values contain x,y,z of DOCA point
• Hits contain ring, straw, tdrift, and dE

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Flowchart from 2005
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Flowchart of current code
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DCDCWire
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DOCAs from DCDCWire
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Still To Do

• Attach z-info to stereo layers in track finder
• Project z-info to axial layers in track finder
• Determine conversion method for tdrift to
  distance from wire.