April 10, 2007 Software

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  1. Review minutes from March 20, 2007 Software meeting
  2. BCAL timing (Blake L.)
  3. CLAS12 GEANT4 hit scheme (Mark I.)
  4. Document for CD-2 (Alex D.)


Cebaf Center F324-325

To connect by telephone: 1.) dial:

800-377-8846 : US
888-276-7715 : Canada
302-709-8424 : International

2.) enter participant code: 39527048# (remember the "#")

We may have a VRVS connection depending if the equipment is in good working order. No guarantees.


Attendees: David L.(chair), Simon T., Elton S., Elke A., Mark I., Eugene C.

On phone/vidcon: Richard J., Blake L., Mijhalo K., Matt S., Alex D.

BCAL Timing

Blake gave an update on the status of the BCAL timing resolution as measured during the beam test last fall. The timing is measured realtive to the photon tagger. There were two issues that caused problems when trying to compare the times of the tagger and the BCAL:

  1. A difference in conventions was used for the BCAL than for the tagger when subtracting off the TDC reference times. This caused some confusion since it meant one needed to add the times instead of subtracting them in order to get a time difference.
  2. A bug in the BCAL TDC code caused the wrong reference time to be used for many events

Blake reported a timing resolution of around 153ps after subtracting off the tagger contribution.

For the most up-to-date details on Blake's analysis, see his BCal Timing Resolution Note.

CLAS12 GEANT4 hit scheme

Mark reported on the GEANT4 hit scheme being developed by CLAS12. This is an extension of HDDS to make it easier to specify the readout scheme inside the XML where the detectors are defined. The work was started by Jorn Langenreich, but he is no longer available so Mark has picked it up.

Mark discussed the non-standard GEANT4 hit scheme with some of the GEANT4 authors who were in town a few weeks ago as a follow up to the GEANT4 Tutorial held in May 2006. They did not raise any concerns over this approach.

There was some discussion over how much work it will take to get this working as opposed to how much it will ultimately save. The current thought is that Jorn has done most of the design work and much of the implementation already. Since the project is general, it might also save time on fast prototyping of new projects.

See Mark's slides for more details.

Action Items

There were no action items discussed.