• for user-supplied devices that are not integrated with the DAQ we will provide a TTL trigger and a network-based timestamp
  • this will be done using a TPR (PC_260_101_04_C02) (https://github.com/slaclab/evr-card-g2) (which only receives L1Accepts, not transitions)
  • the first example of this will be for the timepix detector in RIX in second week Oct. 2021:
    • Chris F. will take the lead on this
    • a machine with TPR will be placed in the rack that has the andor (rack 4?) where we can patch a TTL trigger to the beamline
    • timestamps can be retrieved analogous to this app (https://github.com/slac-lcls/lcls2/blob/master/psdaq/psdaq/app/pvcam.cc)
    • this machine can be a clone of the andor machine, but I think we need tpr-firmware instead of evr-firmware (to be confirmed with Matt)
    • the TPR also needs a standard 12-BNC breakout cable to provide the TTL triggers
    • we will meet with Anton Tremsin to discuss the trigger/network xface
    • this machine could perhaps be reused for RIXCCD so it could use a 10Gb DRP interface.  This could also be used to startup processes with procmgr.

Meeting Notes

9/9/2021 – MCP/Timepix Meeting with Anton Tremsin

  • The Timepix detector is incapable of receiving timestamp information over a network interface. Thus, some other mechanism will be needed to synchronize the timestamps of the Timepix detector and the LCLS DAQ system.
  • The Timepix detector requires two TTL inputs: Reset and Trigger.   The Reset signal must precede the first Trigger signal.
  • The LCLS DAQ developers believe that this Reset+Trigger interface can be integrated successfully for a trigger rate of 120 Hz, which is the short-term goal.
    • We plan to do this with an xpm sequence that runs for the whole run, which generates the reset once at the beginning of the run and then drives L1Accepts for the remainder of the run.  This is inelegant, but acceptable for a short-term test
  • When and if the Timepix detector is chosen for integration at trigger rates greater than 120 Hz, hardware integration with the LCLS DAQ timestamp will be required.


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