D2n kinematics

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Revision as of 22:46, 15 August 2020 by Brads (Talk | contribs) (Non-"production" runs)

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Run Plan (updated when needed)

  • Draft d2n Run Plan
    • NOTE: The SHMS + HMS kinematic pairings are different that what we were planning when those tables were constructed. We are starting with HMS Kin C and SHMS Kin X.
  • Updated rate and yield estimates for kinematics and beam energies below (March 19, 2020) [W. Korsch]

Rough / High-level sketch of d2n kinematic settings

Reduced kinematics list to accommodate limited beam time (dropped 1/4 of kinematics)

      ---------  Beam Params ----------
            E_beam = 10.4 GeV/c
            I_beam = 30 uA
            P_targ = 0.50
            P_beam = 0.80
          ---------  HMS ----------
       E'    theta    x        Q2       W
 A    -4.2   13.5     0.207    2.414   3.178
 B    -4.2   16.4     0.305    3.554   2.993
*C    -4.0   20.0     0.418    5.018   2.806 [Starting here] --  Only setting compatible with SOLID Cherenkov small-angle test.
          --------- SHMS ----------
       E'    theta    x       Q2      W
*X    -7.5   11.0     0.527   2.866   1.859  [Starting here]
 Y    -6.4   14.5     0.565   4.240   2.036
 Z    -5.6   18.0     0.633   5.701   2.046

  • Not shown is the 1-pass running (3'ish days)

Schedule Overview

  • We should expect to have 6 weeks of beam
    • Hall C will have priority over Hall A (if there are beam loading, machine stability issues)
  • Rough priorities:
  1. We plan to start at 5-pass with kinematics A and X (small angle)
    We will start at 5-pass with kinematics C and X (small angle on SHMS, large angle on HMS)
    • This will allow the SOLID Cerenkov prototype folks to setup before beam and run their small-angle test on the HMS side.
  2. Then move to kin A and Z (high-Q2 SHMS, small angle HMS)
  3. Scheduling of Kin B, Y and 1-pass running would depend on how the Accel/target/virus behaves

More Detailed Plan for when beam is handed to us (as of Sunday, August 2)

- Moller measurement will be done on first available day shift -- looks like Monday DAY at this point

- Sanity check beam positions, harp profiles and convince ourselves the tune is still good (no need for Carbon Hole study unless something is really strange) - Ion Chamber calibrations (if not done already)

 - Reference cell filled with N2 @ 10 Atm
 - Carbon Optics

- If the target is still pumping up, or if there are any concerns about the 'real' beam polarization, then

   - Reference cell runs:  2 beam-hours each  (skip He3 for now)
     - N2 @ 10 Atm
     - H2 @ 10 Atm
     - Empty / Vacuum

- Then move into production running:

 HMS Kin C, SHMS Kin X  (Total time:  125 PAC hours, ~10 calendar days)
 - Flip IHWP every 4--8 hours
 - Ensure Charge Asym Feedback is running/working
 - Take NMR meas. every ~5 hours
 - Target:  Transverse
   - Flip target spin at 36 hours
   - 3-4 calendar days in, switch target to Longitudinal
 - Target:  Longitudinal
   - Flip IHWP at 1/2 way into each run block (~4 hours)
   - ~11 hours @   0deg
   - ~11 hours @ 180deg
 - Switch back to Transverse
 - Target:  Transverse
   - 3-4 calendar days until Kin C/X are done
   - Flip target spin at 36 hours in
 - Reference cell runs
   - Complete N2, H2, empty ref cell runs not completed yet (may be used as fill after a target spin flip/rotation)
   - He3 @ 10 hours (2 beam-hours) -- Do this once at the end of this kinematic

- This should take roughly 10 calendar days. - We'll then move to 1-pass for 3 days, then back to 5-pass and follow the above prescription for the remaining Kin A/Z, Kin B/Y

Non-"production" runs

  • Optics are generally in good shape, but we will should take more for HMS kin B (4.2 GeV/C @ 16.4 deg)
    • Analyze and get the new matrices in the analyzer
    • Make sure we have empty target runs for all kinematics help disentangle beamline window contributions
  • Nail down estimates for ref cell running (N2, H2, 3He, empty)
  • Minimal/no positron running?
    • Perhaps measure the positron background in HMS at 13.5 degrees and compare with model as a sanity check? If it matches model, then we can skip the rest?

1-pass running considerations

  • Request pass change to 1-pass
    • Controlled Access to install collimator (RadCon)
    • Check on EPR photo-diode status (replace if needed)
    • Simona will be doing some SOLID Cherenkov work during this time as well
  • Restore 1-pass beam to Hall
    • Moller measurement ASAP
    • Turn off hodoscope bars as before: HMS [1]; SHMS [2]
    • For raster need to have MCC click on the button on the Expert page for 1 coil ( instead of 2 coils). Then need to be sure that to use the "gbeam_pass1_jan2020.param" is being used for analysis.
  • Begin production running following A1n 1-pass notes 1-pass_calibration_for_A1n_(Jan_2020)
  • 3He elastic and QE longitudinal Asymmetries (incl. pressure curve / ref cell running)
    • HMS setting: 11.7 deg, -2.1483 GeV/c
    • SHMS setting: 8.5 deg, -2.12860 GeV/c
  • Polarized 3He Delta Transverse Asymmetry
    • HMS setting: 11.7 deg, -1.75830 GeV/c (electron W=1.232)
    • SHMS setting: 8.5 deg, -1.79736 GeV/c (electron W=1.232)
  • Pol 3He Elastic Measurement (E12-06-121A)
    • Details Coming Soon