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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. (Hanjie available to help with cross-checks?) We need to get this in our hands so we can analyze Q2 data from over the run.
    2. Pointing (Siyu) We need to get to final precision
  • 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. Proposed next meeting: tomorrow at 3:30.