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the two primitives being perfectly aligned. The TKR trigger rate is still ~30% lower that CAL_LO and EXT, though. Following figure refers to a run taken immediately after with a different ext_delay; sorry for the confusion, but it shows how the primitives are aligned.
Need to understand why:
- The TKR trigger rate is lower than the others (maybe worth mentioning that the beam is 5 GeV electrons, 90 Hz average rate, 500 Hz istantaneous).
- The (apparently) optimal setting for the TKR treq_delay is 2 and *not* 5 as expected from SLAC. Does the particle energy makes a difference?
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With these settings the trigger primitives within the trigger window look like this:
How the trigger delay should be set?
The proposed trigger delay settings are fine in case all the trigger primitives are enabled (allowed to open the trigger window), but in the BeamTest only external trigger can open the window so in roughtly half of the event that have an internal trigger we will not see this trigger primitive in the summary word. This can be a problem if people want to study trigger efficiency.
So a second option for trigger settings (to be used in case of ext trigger only) is to delay the internal treq for TKR and CAL by 6 ticks to make the peak in the center of trigger window:
- CAL treq_delay = 0x6
- TKR treq_delay = 0x8
- CAL tack_delay ~ 0x2d-0x2e (nominal)
- TKR tack_delay = 0x0 (nominal)
- delay_ext_trig = 0x8