• Created by Unknown User (kutschke), last modified on May 11, 2007

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 3 Next »

Summary of SiD Tracking Discussions, May 7-11, 2007 at SLAC

Persistency

  • We will only persist the official LCIO objects: SimTrackerHit, RawTrackerHit, TrackerHit and the reconstructed track class ( don't know its proper name).
  • We will work with LCIO to get small changes made to these objects, but not big changes. We will shoehorn our objects into the defined persistent objects.
  • We will not support persistency for other information even if it cannot easily be recomputed.
  • We will not persist clusters.
  • We anticipate that a future evolution of the reconstructed track class ( perhaps it will be
    spelled trajectory, not track ), will allow us to persist residuals.

I view this as too confining. We should be able to persist anything we put into the event, even if that information
is not useful to the other collaborations.

New Geometry

The new geometry is well underway but not yet finished. This is the geometry that
can describe the detector made of wafers. It can also describe a detector made of
cylinders.

RawTrackerHit

We will get LCIO to approve several mods to the RawTrackerHit class and use it as the persistent
representation of a single hit pixel or strip.

Needed Changes

  • getDetectorElement(): Gives access to all geometry info.
  • getCellID(): For us this will return a channel ID on the wafer, not a global ID, although the thing persisted will need to be a global ID.
  • return a List of SimTrackerHits not a single SimTrackerHit.

Consequences:

  • Proper merging of backgrounds can only be done at the SimTrackerHit Level.
  • Merging can be done at the RawTrackerHit level but only using digitized pulse heights.
  • The true pulse height ( non-digitized ) is never available to the user.
  • The breakdown of which track contributed how much to the pulse height is never available to the user.
  • The amount of electronic noise (+ or -) in the pulse height is not available to the user.

Recommendation:

People who write RawTrackerHit creators must be reminded to sum contributions before digitization. There is no support for this is in the class system we have specfied so they will need to do it themselves.

  • No labels