From PREX Wiki
Revision as of 13:03, 10 December 2020 by Kent Paschke (Talk | contribs)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

Back to Main Page >> HRS_Optics_Mtg

previous meeting << >> following meeting

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
      1. additional data?
      2. RMS of data points (each about 0.06 deg uncertainty?)
  • G4HRS
    1. Estimate of ionization energy (constant) offset (Hanjie) Done
    2. Ionization straggling. Defered to post Oct 3.
    3. Build C-Pb-C sandwich targets in G4HRS. (Hanjie? Ryan? Cip?) DONE
      • Verify rate matches previous sims DONE
    4. Survey check (Kent?)
      1. Verify target, septum, Q2 z locations in simulation
      2. Correct G4HRS to Siyu's pointing central angles + beam position offset
    5. Verify sieve hole acceptance in septum scan (Ryan)
      • search for possible clipping in HRS or at Q1 (Ryan)
    6. Verify scattering angle correspondence MC vs data, perhaps central sieve hole? (Ryan)
    7. Generate "Pb" Q2, theta, phi, tg, asym
    8. Generate Pb+C distributions for apparent Q2, theta, phi, tg, asym (for comparison with data)
    9. Sensitivity study for acceptance function Q1 collimator cuts, or polar angle dist.
  • Acceptance function - Data + g4hrs
    1. Detector position sensitivity to analyzing power ("apparent" acceptance function from data) DONE?
      1. Needs to be completed with "publication quality plots" (drop broken S0 runs)
      2. Need estimate of systematic uncertainty for full transverse acceptance, as a function of width in dp cut.
      3. Some kind of summary figure for this.
    2. look for correlation (p vs theta or phi, theta vs phi),
      • match to sim. set limits if non-physical
    3. Acceptance comparison:
      1. Match phi_tg, th_tg, y_tg, dp, th_lab distributions. (data vs g4hrs Pb+C)
        • Compare central values and distributions
      2. match Q2, theta, phi_tg, asym(assume Pb but use all data)
        • Compare values and distributions
      3. Do one Q2 run, but then try others (different targets?)
        • Compare original and disrupted Pb10?
    4. Carbon: rates, apparent asymmetry, vertex asymmetry
    5. Lead: rates, vertex asymmetry
    6. Vertex correction (Ryan, Kent)
  • Radiation Correction
    1. Verify ep variable vs recoil factor calculation, consistency with scattering angle
      • Make map of elemental, vertex, and apparent quantities in g4HRS
    2. Write macro for acceptance function:
      1. cut on lead
      2. Q1 collimator acceptance cut
      3. dp acceptance cut
      4. get as-thrown (lead only), as accepted (lead only). Divide.
      5. Design checks of acceptance function
  • Carbon Background (Sanghwa, Weibin)
    1. Carbon/Lead target thickness.
    2. Cross-check Carbon background.
    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
    1. runlist
    2. Q2/Acceptance function, multiple measurements. Run with new optics DB, compile results (Chandan)
      • Add y_targ to these values
      • Verify scattering angle used (Chandan, Siyu)
    3. Consider possible carbon thickness variation or acceptance function variation as a function of target lifetime (Chandan) Done haplog:4284
    • Previous look at multiple Q2 runs: https://logbooks.jlab.org/entry/3728569
    • Document the following (where is this logged?)
      • detector adc cut
      • detx/dety alignment plots
      • dp plots.
    • Need root files for distribution studies (where is this documented)
      • scattering angle, expected asymmetry, and momentum, and perhaps Q2 calculated two ways (using angle/dp/incidentE and using angle/E_incident)
      • What incident E is used for Q2 calculation? Where is this documented?
      • What p0 is used? Where is this documented per run?
      • Documentation of beam energy per run?


Please post slides in haplog or docdb, before the meeting

  1. Siyu Pointing measurement
  2. Chandan Q2 measurements
  3. Wiebin/Sanghwa Carbon