August 14, 2007 Software

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  1. Review minutes from July 31, 2007 Software meeting
  2. FDC Lorentz deflection/correction [1](Simon)
  3. Wiki authentication (Mark)
  4. Action Items


Cebaf Center F324-325

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Attendees: David L.(chair), Mike W., Mark I., Elliott W., Simon T., Eugene C., Elton S.,

Phone: Andrei S., Benni Z., Alex O. , Richard J.


  • The program pythiagen is now in the repository and can be used to to procude HDDM files. Not all information is copied into the HDDM file right now since the data model doesn't currently support it. More will be presented on this at a future meeting.
  • Elliott suggested moving the action items to another page since this will archive them better, even after they are completed.

FDC Lorentz deflection/correction

Simon presented the current status of his efforts to include the Lorentz effect in the simulation and account for it in the reconstruction. He put the effect in some time ago, but the reconstruction is proving the larger portion of the work. The difficulty is that the sign of the correction depends on whether the track passed on the left side or right side of the wire. The only way to know this from the data is by looking at tracks formed by multiple hits. A considerable amount of work has been done on track finding which incorporates a Riemann fit to get the parameters for a segment which are then used to apply the Lorentz correction. The current algorithm correctly resolves the left-right ambiguity 70-75% of the time. Much of the inefficiency, however, may be coming from the region at the edge of the cell or in the region closer to the wire where the Lorentz effect is less important. This will be looked at in more detail in the future.

Residuals and momentum and angular resoultion were also presented. These were from single segment fits with and without the Lorentz correction. The momentum resolution showed significant improvement, but the angular resolution does not appear to be very sensitive to this effect at all.

Finally, some work was reported on segment linking to form track candidates than can be fit later. Some discussion was had on being more flexible on linking segments with a different charge which could possibly improve the efficiency over what was presented. This will be looked at.

Wiki Authentication

Mark proposed removing the password protection on the Wiki required to simply read the pages. At the same time, the ability to have anyone create their own account would have to be removed. The new system would require them to request an account from the wiki master(s) who would create it for them. A vote was taken as to whether to adopt this change and it was unanimously accepted. Mark will implement the change.

Action Items

  1. Remove read-only password for Wiki
  2. Complete "Version 4" Simulation geometry document. (David, Simon)
  3. Put updated collaboration list in DocDB and commit list to repository (Zisis)
  4. Develop system for incorporating alternative b-fields in simulation (Richard and David)
  5. Look at recent FDC geometry changes (Richard)
  6. Create an easy way to produce radiation length plots and document it (David)
  7. Review the digitization scheme(s) we have now and figure out how to make them more coherent (??)
  8. Remove "default" from calibration file directory path(David)
  9. Tie HDGeant and DANA constants to single source (David)
  10. Output configuration parameters database from DANA