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Logistic information

 Time: 12:30-1:30
 Toll-Free Number (U.S.&  Canada):  888-240-2560
 PARTICIPANT CODE:                  #543 006 042 
 Room IRL:                            <none>


  • Optics and Pointing
    1. Optics database. We need to get this in our hands so we can analyze Q2 data from over the run. (Near Done?)
    2. Pointing (Siyu) We need to get to final precision (Near Done)
  • G4HRS and energy loss
    1. Estimate of ionization energy (constant) offset (Hanjie)
    2. Ionization straggling. This may require an improved vertex handling. Defered to post Oct 3.
  • Acceptance function
    1. Build C-Pb-C sandwich targets in G4HRS. (Hanjie? Ryan? Cip?)
    2. Detector position sensitivity to analyzing power ("apparent" acceptance function from data) (Devi, Bob, Kent )
    3. Sensitivity study for acceptance function Q1 collimator cuts, or polar angle dist. (Devi, Bob, Kent )
    4. Verify sieve hole acceptance in septum scan (Ryan, Kent)
    5. Verify scattering angle correspondence MC vs data, perhaps central sieve hole? (Kent, Ryan)
    6. Vertex correction (Ryan, Kent)
  • Carbon Background (Cip, Weibin)
    1. Carbon/Lead target thickness.
    2. Cross-check Carbon background. (Cip, Weibin)
    3. Simulate Carbon acceptance with radiative tail
    4. Separate Carbon/Pb distributions from sandwich targets
    5. Compare C12 acceptance to C12 distribution from Pb targets, for Q2 comparison.
    6. Calculate average carbon contamination fraction, and kinematics (for correction)
  • Q2 data set (Hanjie, Chandan)
    1. runlist
    2. Q2/Acceptance function, multiple measurements. Run with new optics DB, compile results (Hanjie)
    3. Consider possible carbon thickness variation or acceptance function variation as a function of target lifetime (Chandan)
    • Previous look at multiple Q2 runs: https://logbooks.jlab.org/entry/3728569
    • With some additional care for the following:
      • care for the detector cut
      • Also plotting the scattering angle, expected asymmetry, and momentum, and perhaps Q2 calculated two ways (using angle/dp/incidentE and using angle/E_incident)
      • We need to get incident E correct (average energy loss before vertex… just a number we will get from sim)
      • keep track of the detector alignment, dp and spectrometer p0 so we know if variations imply a change in the acceptance function or just an alignment change
      • keep track of beam position - this was a dominant source of variation in past runs, as one arm went up in Q2 and the other went down due to x-position differences


Please post slides in haplog or docdb, before the meeting

  1. Next meeting: Friday, 12:30
  2. Saturday, 11:30-4 is analysis summary meeting