Below are the calibration dataset considerations for isobar needs in Run 18:

• EMC
  • emc-check runs once per fill (at the start)
    • For the purpose of EMC pedestals and status tables
    • 50k events
• TOF
  
  • VPD
    • Resolutions needs to be calibrated (for trigger) and confirmed to be similar for both species
• TPC
  • Laser runs
    • For the purpose of calibrating TPC drift velocities
    • Every few hours (as usual)
    • Either dedicated laser runs, or included in physics runs
    • ~5000 laser events
  • GMT inclusion in a fraction of events
    • For the purpose of understanding fluctuations in TPC SpaceCharge
    • Trigger choice is not very important, as long as it has TPX and during most physics running
    • Something around 100-200 Hz is sufficient (too much will cause dead time issues for the trigger)
  • Vernier scans
    • For the purpose of understanding backgrounds in the TPC that may be different between species
    • Once for each species under typical operating conditions
    • 4 incremental steps of collision luminosity, each step ~1 minute long and on the order of ~50k events (total = ~4 minutes)
    • TPX, BEMC, BTOF must be included
    • Minimum bias trigger with no (or wide) vertex z cut
    • link to old study
  • Low luminosity fill IF a TPC shorted field cage ring occurs
    • Only one species needed (unimportant which)
    • Minimum bias trigger with no (or wide) vertex z cut
    • ~1M events
    • ZDC coincidence rates below 3 kHz
  • Old ALTRO thresholds run
    • For the purpose of TPC dE/dx understanding
    • Only one species needed (unimportant which)
    • ~2M events
    • Could be at the end of a fill, or any other convenient time during typical operations
  • Magnetic field flipped to A ("forward") polarity before AuAu27 data
    • For the purpose of acquiring sufficient cosmic ray data with both magnetic fields to understand alignment of new iTPC sector

-Gene