GlueX Level-3 Trigger Meeting, Apr 20, 2017

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Meeting Info.

Meeting Time And Location

15:00 EST (JLab time)

CC F326


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Background Information

(Click expand for some links to background information -->)

Base Material

  1. David L. 1/23/17 L1 meeting
  2. Alex S. collab. meeting talk
  3. David L. collab. meeting talk


  1. Announcements
    • Date change: Review will be 1 week earlier on May 11 13:00-17:00
  2. Previous Meeting (Apr 13, 2017)
  3. Current Status
  4. May 11 review
  5. AOT


Attendees: David L., Sergey F., Alex S., Eugene C.

  • We discussed the current status of the trigger rate and event size projections in order to catch Eugene up
  • There was consensus that with the existing readout hardware rate limitations and reduced event size, a L3 farm solution is no longer warranted. We will present a high intensity running solution at the review that does not require L3 farm.
  • There was some discussion on how to present the FCAL+BCAL+ST trigger.
    • Without the ST in the trigger and using our Spring 2017 FCAL+BCAL thresholds we would be near (and possibly slightly over) the hardware limits for data readout when running 5 x 107 γ/s. This would leave no margin.
    • With the ST in the trigger the L1 rate is reduced by a factor of about 1.6
    • Eugene suggested we look at existing data for a channel that may be affected by an ST cut (e.g. γp -> ωp -> πoγp) and see what is thrown away if an ST is required
  • Items needed for high intensity running that will need to be budgeted:

Action Items

  • Compare most recent data volume estimate provided to CC to one using a 2GB/s data rate. Discuss with CC to see if this causes any concern (David)
  • Look at γp -> ωp -> πoγp channel and see what is discarded when ST hit is required. (Alex, David)
  • Start outlining talk and gathering slides so we can review at next meeting (David)

Next Meeting

We will meet again on Thursday next week at 3pm. Room A110 is reserved.