Difference between revisions of "CREXAuxiliaryMeasurements-Aug2020"

Latest revision as of 17:27, 16 September 2020

CREX Main << August 2020 CREX Run Plan

Schedule

• This plan is evolving as we move along

Optics and Q2

1. Q2 measurement (Done)
   • Repeat of Q2 measurement, with improved pedestal noise control.
   • Detector counting mode.
   • S0 trigger
   • production raster and beam position
2. Optics Data (Done)
   • Sieve IN, dp=+1, 0, (maybe -1). Raster/no raster thin C, raster H20
   • Priority is 1 dp change (both arms!) plus backout, and 10 runs. Watercell runs should be long.
   • Assume 3 hours for magnet changes and 2 hours for data taking. ~ 1 shift
   • See grid on optics data spreadsheet
3. Energy Measurement (Done)
   • Doug did a parasitic energy measurement Sun, Sep 13 at 20:24 [4].

Backgrounds

1. Blinded At PMTs (Done)
   • Longish access to setup and back out, but short data taking period (production conditions).
   • Reconfigure AT PMTs to use blinding cap, attach to US PMTs.
   • This will be done during the long beam studies break on Monday
   • software blinding on the AT PMTs must be disabled
   • Check pedestal noise in counting and in integrating mode. We need low noise is the blinded tube, and we can't add noise to our main detector!
   • Integrating measurement for asymmetry measurement
   • (Do we want counting mode measurement for rate in blinded At tube?)
   • (yield only normalizable using table-gain gain curves).
2. Blinded Main detector? (Done)
   • Need 2 hours to blind main detectors. Then another hour after meaurement to unblind.
   • short-ish yield runs in integrating mode.
     • Software blinding must be disabled on the blinded MD tubes for this study
   • short counting mode run to get relative rate
   • Then return. Keep AT blinded piggybacked for asymmetry measurement.
3. Inelastic spectrum scan (Done)
   • Needs a detailed run plan
   • Counting mode. Current 0.5uA or so? Turn quartz HV off.
   • Measure dp spectrum form dp=nominal to dp=-25%, in 5% steps. Use LHRS only.
   • should scale all spectrometer magnets (including septum)
4. Pole tip re-scattering (Done)
   • Counting mode (VDC tracking). Counting mode on detector is ok (and helpful) but not needed.
   • Q3 turned off.
   • Run three septum setpoints: nominal, -5%, and +5%. Need ~1M S0 trigger events per run (and more is better).

Detectors

1. Linearity Studies (PITA + current scans)
   • These are ongoing - should continue regularly. One more, on last day.
   • Current scans for detector and BCM pedestals. Skip the BPMs, I think.
2. Linearity LED tests
   • This will be studied post run, during SAD
   • detector crew were left off the SAD access list - Access will be approved. Reapply for access.

Other

1. Sign check, done
   • perform at next Moller polarimeter measurement
   • run Moller, Compton, and parity DAQ for quick PITA scan [5]
2. Target/Raster study
   • Set up for normal production mode. Call in experts (Bob M in person, Cameron remote).
   • With each raster change we start with a brief C12 run for safety, then do a brief Ca48 run.
   • Raster Scan Run Plan

Moller polarimetry

1. One more measurement, done [6], [7]

Compton polarimetry

1. Spectrum run
2. Laser polarization changes - aborted
3. linearity studies During SAD