Tracker Recon Fit Track TDS Class(es)

 

• Global Track parameters (contained in a TkrFitTrack class)
  • A track status mask containing information about the fit status/type/quality/etc. of the track
  • A track identifier or label?
  • The (x,y,z) coordinates of the start of the track (taken at the first hit)
  • The (x,y,z) direction cosines of the start of the track (taken at the first hit)
  • The track energy (the best estimate of the track energy after track fit is done)
  • The track chi-square from the filter stage of the Kalman Filter
  • The track chi-square from the smooth stage of the Kalman Filter
    • If running a least squares fit then, presumably, both would be filled with the same value
  • The rms of hit residuals
  • The total radiation lengths from track beginning to the plane of the face of the calorimeter
  • Kalman Filter specific quantities:
    • Track energy estimated from Kalman Filter fit information
    • The estimated error on the above
    • The rms multiple scattering angle for the track
  • Addition information to be stored(?):
    • Track quality
    • Number of x gaps (also in first hits)
    • Number of y gaps (also in first hits)
    • "numSegmentPoints"
    • "chisqSegment"
    • Number of x plane hits
    • Number of y plane hits
  • Methods to provide (in addition to "get/set" types of methods returning above information)
    • Return track parameters at any hit along track
    • Return track parameter errors at any hit along track
    • Return Gaudi pointer to an individual plane
       
• Parameters global to a plane (contained in a TkrFitPlane class)
  • Basic parameters global to a "plane" consist of:
    • The volume identifier
      • Gives tower, tray/plane, view, etc. information
    • Boolean value to indicate that a cluster is associated with this plane
    • Gaudi pointer to the cluster associated to the plane (if exists)
    • Track energy at this plane
      • The value determined by the particular energy loss formula used for the fit
    • z-coordinate of this plane
  • Additional parameters that are desirable (can be saved in an associated "work" class by fitter)?
    • Radiation lengths from the previous plane
    • Active distance to the ssd edge
    • Multiple scattering covariance matrix from the last hit
       
• Parameter types
  • Basic hit data consist of:
    • Track Parameters: x position, x slope (or tan(q)), y position, y slope
    • Track Error matrix: 4x4 matrix describing errors on above
  • Describe four categories of track parameters:
    • Measured - the physically measured values of the above parameters
    • Projected - the estimated values from projecting from a previous plane
    • Filtered/Fit - the values after the "Filter" stage of the Kalman Filter
    • Smoothed - the values after the "Smooth" stage of the Kalman Filter
  • Structure:
    • Track Parameters and their error matrices are described by small standalone classes
    • They are only data storage
    • They are accessible only through the plane class above.
    • These are contained by a "hit" class which also describes:
      • The type of hit
      • The z coordinate of the hit
      • the Volume Identifier of the hit

T.Usher Last Modified: 07/14/2004 18:57