WAC Notes November 12 2020

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PREX Main << Weekly Analysis Coordinator << WAC Notes CREX << WAC Post-Run_Meeting Notes

WAC Notes November 5 2020 << >> WAC Notes November 19 2020


Date and time: November 12, 2020, 11:00am
Bluejeans ID: 454783784
Meeting link: https://bluejeans.com/454783784
Runlist spreadsheet

Suggested Changes

Each WAC will suggest changes for their run period, which will be discussed at this meeting:


Beginning of run period 2 - Slug 186

Beginning of the second run period. It is in identical conditions to how we left in March.


  • The pedestals were obtained AFTER the run began, so the first set of pedestals (or global pedestals) need to be updated and back-propagated to this run period as well.

Cuts: Stability cuts were removed, due to the FFB noise in BPM Ys - https://logbooks.jlab.org/entry/3824620


  • Slug 186 - 7626 - was not included before - is the very first run, it has 5 sigma Aq (no Aq feedback) and FFB commissioning/noise, but otherwise is fine
  • Slug 186 - 7627 - was included before - Has 2 sigma Aq (bad Aq feedback). Also, FFB turning on an off is a mess, but as far as I can tell, there is no negative impact on slopes or corrections (so it should be tolerated)
  • Slug 186 - 7628 - needs cuts - One very brief 1.5 mm 12X jump
  • Slug 186 - 7630 - needs cuts - Another brief 1.5 mm 12X jump
  • Slug 186 - 7631 - needs cuts - Another brief 1.5 mm 12X jump
  • Slug 186 - 7632 - Really huge FFB noise... is it worth keeping the 150um + BPM Y RMS data? X is OK.
  • Slug 186 - 7634 - Really huge FFB noise still
  • Slug 186 - 7635 - BPM 1 YP wire looks fishy, otherwise OK. Some BPM 12X noise, very brief. Same FFB noise problems as before.

Day 2 - Slug 187

After a day of work we get more data, with still bad FFB for a while and adjusting tunes.

Also, counting mode alignment run verified the HRSs see different accepted rates (same positions as March running) - https://logbooks.jlab.org/entry/3825555


  • Slug 187 - 7657 - was marked as suspicious - Just normally noisy run, should be fine actually.
  • Slug 187 - 7658 - expect detector slopes to change, as there was a gang phase adjustment. Compton rates and BPM noise gets muuuch better

Slug 188

Relatively stable running, FFB is now less problematic (still not great) - https://logbooks.jlab.org/entry/3826256

  • Slug 188 - 7681 - Some BPM 12X large noise

Moller quad gets tuned before 7693 - note that we do change which set of coils is used for BMOD analysis and this may be the time that happened? - https://logbooks.jlab.org/entry/3826547

  • Slug 188 - 7701 - needs burp cut change - Final FFB on run, has hairy noise (burp cut??) that gets cut too often

Slug 189

BPMs are highly correlated (more so than in prior run periods, killed Japan regression until a code change to make that feature ignored) - https://logbooks.jlab.org/entry/3826978

BMOD ramp channel changed, new pedestal was put in place - https://logbooks.jlab.org/entry/3826991, https://logbooks.jlab.org/entry/3827262

FFB Off begins now, meaning dpp drifts are a major concern and should be tracked in 12X studies and counting Q2 impacts.

Initial detector and monitor pedestals - 7708 (PITA), 7710 (unser), 7711 (BPM), 7712 (detector) - https://logbooks.jlab.org/entry/3826991, https://logbooks.jlab.org/entry/3827133

There is another, temporary moller quad tune for the second half of slug 189, and 190 (except for final run 7759) - https://logbooks.jlab.org/entry/3827664


  • Slug 189 - 7707 - BPMs 12 and 11 have a weird motion to them... probably real?
  • Slug 189-LHRS only - 7716, 7717 - both runs are LHRS only (and so is the last half of 7715, which is currently set to all cut out) - is it worth it to keep these runs by themselves? Probably yes, just need to be careful as in PREX times. Map files treat them correctly (not blinded, not normalized - adding 2nd half of 7715 would require a separate analysis + map files treatment).
  • Slug 189 - 7718 - needs improvement - BPM noise is larger I guess, and causes burp cut to slice away a lot of the events
  • Slug 189 - 7734 - New Moller quads tune, slopes/sensitivities likely change a lot. Large Aq, but it's OK. BMOD looks reasonable - https://logbooks.jlab.org/entry/3827755

Slug 190

Slug 191

First indication that the BCM temperatures are not proper (too high, consistent though) - https://logbooks.jlab.org/entry/3828222

The septum had not been cycled - potentially concerning, given the Septum field maps being a cause for concern in simulation land for CREX and the Tune P not scaling up from PREX II to CREX - https://logbooks.jlab.org/entry/3828323

Hall A Dpp shenanigans begin - https://logbooks.jlab.org/entry/3828490






  • Need global cuts on ATs