2016 Request for cosmics with magnet ON

  • GMT trigger and reconstruction software are working well
  • Preference is to have ~5-10k tracks per module at each polarity of magnetic-field-on to have pT-dependence of TPC track residuals with GMT hits (distinguishing different effects requires looking at pT-dependence)
    • pT-independent examination requires ~1k tracks per module (essentially assumes all effects seen are alignment)
  • Endcap GMT modules see ~50% statistics of central GMT modules (simply acceptance), so they determine the statistics needed
  • Taking cosmics with the TPC Gating Grid in an always-open state has been found to produce significant distrotions induced by ions flowing back into the TPC from the anodes
  • Using statistics of runs taken in January 2016, we get ~500 tracks in the least populated GMT module per day
    • We made a You do not have access to view this node that put the estimate at ~1k tracks per module per day not accounting for 50% acceptance at endcaps: these numbers match!
  • So far, we have accumulated ~9 days integrated of RFF comics, and it is likely that we'll get a bit more RFF during other down days through the rest of Run 16
  • Initial conclusion: we will likely reach the minimum goals for TPC-GMT data for RFF by the end of Run 16 without taking any RFF data during the ~two week down time
  • Options for cosmics during the ~two week down time:
    • Zero field: not significantly helpful in studying TPC distortions
    • RFF: could double the statistics by running ~10 days
    • FF: could reach the minimum statistics by running ~10 days  <== This is the TPC group's preference