20200929-Optics-Mtg

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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>
 https://bluejeans.com/543006042

Plan:

• 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

Agenda

Please post slides in haplog or docdb, before the meeting

1. Proposed next meeting: tomorrow at 3:30.