D2n Run Plan 2020

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 -- Currently here (will take positive pol. data here too)
 B    -4.2   16.4     0.305    3.554   2.993
 C    -4.0   20.0     0.418    5.018   2.806 -- Started here (only setting compatible with SOLID Cherenkov small-angle test); will return here after 1-pass

          --------- SHMS ----------
       E'    theta    x       Q2      W
 X    -7.5   11.0     0.527   2.866   1.859 -- Started here, still here
 Y    -6.4   14.5     0.565   4.240   2.036
 Z    -5.6   18.0     0.633   5.701   2.046 -- Next setting after 1-pass running

Run / Shift Schedule

• We started taking on Swing on Aug 7 (took a few days for beam to stabilize)
• Beam is scheduled to turn off 8am, Sept 21 (roughly 6 weeks) [1]
• Hall C Shift Schedule

Data Collection Status

• Data collection status is best monitored using d2n_status_table on cdaq@cdaql1

[cdaq@cdaql1 ~]$ go_analysis pro
cdaq@cdaql1:~/polhe3/production/hallc_replay$ d2n_status_table 

• That table is also posted to the HCLog every shift with the subject "Recent SHMS and HMS run list".

  • You can use the Hall C Run List Summaries link under the HCLog Useful Links sidebar on the right as a shortcut.

• The runtimes and estimated yields are based on Rate Estimate Updates (19 Mar 2020) by Wolfgang

  • (NOTE: Ignore the primed kinematics in the file, they are not relevant anymore.)

Special Runs

• BCM Calibration -- Complete https://logbooks.jlab.org/entry/3824242
• Bulls Eye Scan -- Done for A1n (do we want a repeat?)
• Beam Energy Measurement

Notes for Near Term Running

This will be updated frequently

---

1-pass Running

---

 - See dedicated section as well
 - We will be setting up Tommy for the next cell
   - Butterball has the wrong dimensions

---

Longitudinal Running

---

 - That would place the longitudinal running for this kinematic pair (Kin-A, Kin-X) starting
     next Thursday swing following the Moller.
 - Once we have the needed longitudinal statistics (1--2 days), we will collect the remaining
   reference cell data (including He3!) and perhaps do a beam energy calibration before moving\
   to 1-pass on Monday, Aug 24.

---

Remaining Reference Cell running at current settings

---

                    Kin-A    Kin-C    Kin-X
 - REF-Hydrogen      42%       0%*     114%    (collected)
 - REF-Nitrogen      97%      76%*     121%    (collected)
 - REF-Vacuum        46%      --%*      45%    (collected)
 - REF-He3           --%      --%       --%    (collected)
   - make He3 the last ref-cell fill at 5-pass, so we can do the pressure
     curve run on He3 at 1-pass

---

Positron Running (pair-sym BG study)

---

- Consensus seems to be to take some positive running data on Kin-A

  13.5 deg, p0=-4.2 GeV/c [x=0.207 Q2=2.414 W=3.178]

- Good time would this Tuesday--Wednesday

 - Switch HMS polarity Tuesday morning and run through to Wed Day
   (It would not be worth the overhead of flipping the polarity during Swing/Owl.)
 - Access on Wed morning to flip polarity back (2--3 hour downtime)

- We will also follow up on existing data from Marathon and F2 that may overlap with our kinematics

---

Pol 3-He Cell Change

---

- Do this after the 1-pass running (Start Day shift, Thurs Aug 27) - Do Moller and Ref Cell running as needed at 1-pass while testing and spinning back up

5-pass Production Procedure

• SHMS and HMS runs are independent, but are run in pairs that should reflect similar rates (when posible)
  • Run time for each of the 3 kinematic pairs is roughly 125 PAC hours, ~10 calendar days/pair

• General considerations

- Flip IHWP every 4--8 hours (coordinate with Hall A)
- Ensure Charge Asym Feedback is running/working (watch the stripcharts and coordinate with Hall A)
- Take NMR meas. every ~5 hours
- Schedule a Moller run roughly every week
  - Target spin rotations/tests should be done immediately prior to the Moller so target has time to spin back up

• Reference cell runs needed for all Kinematics (nominal 2--4 hours per kinematic)

 - Reference cell Nitrogen [135 psig]  (Insert when we need time to spin up Polarized Cell)
 - Reference cell Hydrogen [135 psig]  (Insert when we need time to spin up Polarized Cell)
 - Reference cell Vacuum   [0 Torr]    (Insert when we need time to spin up Polarized Cell)
 - Reference cell He3      [135 psig]  (NOTE: Make best use of He3 by running this last in first kinematic, then first in next kinematic!)

• Polarized 3He Target • Transverse (90, 270) • Total run time 8--10 days

- Flip target spin after 3--4 days
- Run 3--4 more days with the opposite target spin

• Polarized 3He Target • Longitudinal (0, 180) • Total run time ~1--2 days

 - Flip IHWP at 1/2 way into each run block (~4 hours)
  - ~11 hours @   0deg
  - ~11 hours @ 180deg

1-pass Running

• Pass change to 1-pass: 8am Monday, August 24
• Pass change to 5-pass: 8am Thursday, August 27
• That is a nominal 64 hours (assuming 8 hours for pass change)

- A1n 1-pass running notes:

 https://hallcweb.jlab.org/wiki/index.php/1-pass_calibration_for_A1n_(Jan_2020)
 https://hallcweb.jlab.org/wiki/index.php/1-pass_calibration_for_A1n

• Verify the following well before 1-pass period

 - Confirm SHMS + HMS 1-pass optics is good!
 - Ensure the 1-pass analysis scripts are ready (Scott, Chao); Chao reports that is ready to go now
 - Confirm the T2/T3 trigger (3/4+cher) is ready to go (Brad)

• Necessary Prep work during Hall Controlled Access (schedule with RadCon in advance)

 - Install collimators (JP, RadCon)
 - Check on EPR photo-diode status, likely replace it (RadCon)
 - Ensure fast raster is reconfigured correctly (Expert: Jones, Gunning)
   - "Have MCC click on the button on the Expert page for 1 coil (instead of
     2 coils). Ensure "gbeam_pass1_jan2020.param" is used for analysis"

• Moller Measurement ASAP (also allows target to spin up after above prep work)

  • Precision on this measurement does not have to be perfect -- mostly a sanity check to ensure there are no surprises

• Turn off SHMS/HMS bars following A1n example

   https://logbooks.jlab.org/entry/3756736
   https://logbooks.jlab.org/entry/3760238

1-pass Runs

• Pressure curves (~ 6 hours)

 - Record ref cell pressure before and after each run!
 - He3       : 10,  8,  4,  2,  1,  0.5 atm  (20 min/run) -- 2 hours/setting + overhead
 - Nitrogen  : 10,  8,  4,  2,  1,  0.5 atm  (20 min/run) -- 2 hours/setting + overhead

• Hydrogen elastic [10 atm] (1 hour)

• Reference Cell vacuum (2 hours)

• Pol He3 Delta Transverse ( 4--8 hours )

• Pol He3 Elastic and QE longitudinal Asyms ( 4--8 hours )

 * Pol He3 Elastic group has run simulations and recommend that we start
   with the SHMS at 11deg (instead of 8.5deg).
   - That shows an equal or better FoM, and we are less exposed to the
     high-rate backgrounds, and will /not/ require extra staff support and time
     to rotate SHMS to that angle.

 - Collect our baseline Pol He3 Elastic asym at 11 deg, then continue with
   the Pol He3 Elastic group's run plan (stepping the SHMS out in angle)
   until we run out of beam time.
   - HMS will remain parked at around 18.5 degrees