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RunPlan20161003-

It is likely that we will be running from Monday 3rd with the same magnets available as we had over the weekend. That is:

  • ECE M2 M1 in SSU but no trim power supplies
  • FC
  • ECE in SSD but no trim power supplies

all in solenoid mode. The aim of the data taking is principally to do the scattering and energy loss measurement with field on. To support this we should try to validate/measure the magnet alignment. It is desirable also to do emittance reduction measurement.

We currently have, on the books,

  • 80k TOF2 triggers at 140 MeV/c, with 6.1.4
  • 90k TOF2 triggers at 170 MeV/c, with 6.1.4
  • 70k TOF2 triggers at 200 MeV/c, with 6.1.4

Details

Nominal p Time Taken CDB N TOF1 Triggers N Events TOF1 SP Cut TOF2 SP Cut Tracks Cut Trackpoint Cut TOF12 Cut* Any Cut
140 ~6 hrs 132932 96112 65954 22867 23588 24035 58459 9493
170 ~5.25 hrs 143661 85251 84083 17594 27059 27408 78360 7735
200 ~4 hrs 159749 116582 114837 17142 17709 17924 111593 8767

*Nb: if there is missing TOF1 or TOF2, the cut accepts this event

6.1.4 was optimised to get good transmission at 240 MeV/c, assuming beamline is correctly matched to magnets. So, here are possible magnet settings for next week (and the next):

  • assume we want 100k TOF2 muons at each of the 140, 170, 200, 240 MeV/c settings. Rate is roughly 10k muons per 6 hours assuming no calibration issues in numbers above
  • implies 60 hours per setting = 4 days => 16 days of running required (no contingency, no maintenace days)
  • optics/alignment scans...
  • Ao's settings...
  • Why is the transmission so bad (~25 %)?
  • Nb: user run ends October 28th; we aimed to get a LiH absorber changeover done starting 10th October
  • I would add 30 % contingency
  • DS could be back on 10th October (factor 3 in rate?)

That would take until October 20th. User run ends October 28th, so we would be unlikely to get an absorber changeover and finish the scattering data set (another 5 days to do the absorber changeover, plus another 1000k events required => 8 days + 3 days contingency).

To make a decision:

  • Quantitative argument for what is the statistical precision we require to do the energy loss measurement
  • Quantitative argument for what is the statistical precision we require to do the scattering measurement
  • Quantitative argument for what is the statistical precision we require to do the alignment
    • Corollary - what is the alignment precision required?
  • Quantitative argument for what is the statistical precision we require to do the heating measurement
  • How long will the absorber changeover take?

Updated by Rogers, Chris over 6 years ago ยท 15 revisions