IntegrationDaq 210716

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Meeting information

 Meeting time:  3:30pm Eastern
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  • Progress on prototype
  • Discussion on trigger/event timing
    • We plan to run MOLLER with a 10us "spin flip" period. The beam travel time from injector to the hall is ~20us, so a new helicity integration window starts in the injector while the old integration window in the hall is finishing.
      • How best to coordinate starting the integration and building events? We had discussed having the time shift done in the TI connection.
      • Should INJ and hall readout be coupled or independent (baseline design concept has them coupled)?
  • Signal cable and signal level adaptation
    • For the BPM signals (up to 5V, single-ended signals on coax), what I recall discussing was that we would have an option to short one side of the twin-ax cable, and could also use attenuation to get the signals within the range accepted by the ADC
    • We'd also need some sort of cable adaptation to go from the coax to the twinax
    • Should we think about doing this as some sort of panel to which we connect both cables, or should we think about doing it with a cable that has a twin-ax connector on one side and a BNC on the other?
  • Activity updates
  • General discussion


Recording on [1]

Participants: Robert Michaels, Paul King, Bryan Moffit, Chris Cuevas, Michael Gericke, William Gu, Brynne Blaikie, Daryl Bishop, Jim Fast

  • Progress on prototype
    • Daryl has gotten feedback from Chris and William and made some changes; he'd like William to verify that has corrected the issue. Daryl is updating the bill of materials and finalizing the layout. Expects to finish in a day or two.
    • Michael has 5 of the SOM and 85 of the ADC chips on-hand, as well as many of the other components needed. However, the BOM he'd been working with was outdated, so some of the components ordered aren't what we will want. He has paused ordering and will resume when he has the new BOM from Daryl.
  • Signal cable and signal level adaptation
    • Jim asks if there might not be an already existing adapter to go from BNC to our twinax connector. Daryl thinks there may be one offered by Pasternack.
    • Alternately, Daryl says that it would be possible to have a footprint on the board to be able to install a BNC connector instead of the twinax connector for the "beamline" modules. We could then have some spare modules that don't have the connectors added, such that we could decide to populate them as a detector module or a beamline module. This was the beamline signals would be brought in and connected to the ADC as a coax BNC, without needing any adaptation.
      • Michael questions if this would require a big change in the front-end circuit (or if doing it without change would result in a big change in the main filtering circuit). Daryl says that it would make a little change in the initial 1-pole filter, but that the most of the filtering happens in the following 7-pole filter, and that would behave the same.
    • What input impedance should we have to match to the beamline signals? Paul will check into that.
    • The initial prototype run will all be built as detector modules.
  • Discussion on trigger/event timing
    • Bob points out there are some studies (such as adiabatic damping) where we would want to be able to correlate data in the injector and the hall, so it would be better to have the two linked into one DAQ.
    • We defer this discussion until Paul prepares a timing diagram.
  • Activity updates
    • Bob and Paul should have a discussion to determine what CODA modules we need in the test stands, and then talk to Chris about how to get those modules.