Fragments (to be reviewed)

referring to fragments of an event as collected from the various SEBs :

fragments 1-9 from TPC

Each one of the SEBs, SEB01 - SEVB09, is getting the signal from its correlated crate, and send the resulting fragments to the EVB.

fragment 10

SEB10 is getting the output of the PMT, and sends the resulting fragment to the EVB.

fragment 11 trigger

In addition SEB10 is sending the following as fragment11:

  • Trigger fragment determines event time: when fragment is collected on SEBs, we timestamp (ntp time from machine), and that’s used for event time later
  • NTP time typically accurate to ~10 ms, Good enough to match to beam data
  • GPS time has been auxiliary/used as check, though critical for future TPC/CRT data matching
  • Trigger fragment records hardware trigger info à doesn’t include software trigger info (separate product)
    Hardware trigger types: BNB, NuMI, EXT (literally a pulser, vetoed by presence of beam gates), MUCS, LASER