Trigger alignment

Tentative trigger alignment procedure:

Initial settings:

namely nominal SLAC settings (CAL treq delay = 0, TKR treq delay = 5, CAL tack delay ~ 45, TKR tack delay = 0). Also the delay_ext_trig is set to 0x0, at the beginning.

With these setting the trigger panel in RunControl (run 700000799) shows that, within the trigger window:

• TKR peaks at 10 ticks.
• CAL peaks at 7 ticks.

Also note that the CAL_LO and EXT trigger rates are almost identical, while the TKR is lower by ~ 40%.

Then next try is the following:

with delay_ext_trig set to 0x5. With these settings:

• TKR peaks at 3 ticks.
• CAL also peaks at 3 ticks.

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?

So here is the proposal for the data taking during the beam test:

• CAL treq_delay = 0x0 (nominal)
• TKR treq_delay = 0x2
• CAL tack_delay ~ 0x2d-0x2e (nominal)
• TKR tack_delay = 0x0 (nominal)
• delay_ext_trig = 0x8

With these settings the trigger primitives within the trigger window look like this: