Difference between revisions of "5-pass production for A1n"

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For polarized 3He running in Fall 2019 and Spring 2020, the nominal raster for production is 5mm diameter circular. The nominal triggers used are 3/4 for both HMS and SHMS. Both HMS and SHMS should be taking data (for example if run plan specify one run, it means one run on HMS and one run on SHMS simultaneously). No coincidence trigger will be used/setup.
 
For polarized 3He running in Fall 2019 and Spring 2020, the nominal raster for production is 5mm diameter circular. The nominal triggers used are 3/4 for both HMS and SHMS. Both HMS and SHMS should be taking data (for example if run plan specify one run, it means one run on HMS and one run on SHMS simultaneously). No coincidence trigger will be used/setup.
−
 
−
For 5-pass production of A1n, we will do the high x setting (large angle) first, then rotate the target. After target rotation we will take low/medium x data for A1n, followed by the d2n experiment.
 
  
 
[[Polarized_Helium-3_Experiments#Run_Plan]] <- click this to return to main run plan page
 
[[Polarized_Helium-3_Experiments#Run_Plan]] <- click this to return to main run plan page
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== Beam and raster checkout ==
 
== Beam and raster checkout ==
  
−
   Please refer to [https://hallcweb.jlab.org/wiki/index.php/2-pass_commissioning 2-pass commissioning procedure], follow:
+
   Please refer to [[Beam and Raster Checkout for A1n/d2n (Short Procedure)]].
−
   - Establish beam in the hall
+
  Or [[Beam and Raster Checkout for A1n/d2n (Long Procedure)]].
−
   - Initial Raster checks
+
 
−
   - Harp scans
+
== BCM Calibration ==
−
   - Target/Beam centering, Raster calibration
+
  '''Goals '''
 +
  - BCM Calibration
 +
 
 +
  '''Procedure'''
 +
  - Follow draft instructions here: [https://hallcweb.jlab.org/doc-private/ShowDocument?docid=957 Non-invasive BCM calibration procedure for 3He running 2019-2020]
 +
   - Per Dave G.'s request please add two more points below 1uA, for example 0.5uA and 0.8uA.
 +
 
 +
== Glass Cell Current Scan/Checkout and Commissioning ==
 +
   '''Goals '''
 +
   - Make sure we can put 30 uA of beam on the glass cells (Reference cell, Polarized 3He cell).
 +
   - Jianping must be present.
  
−
== Moller Measurement ==
+
  '''Setup'''
−
   - Will need 8 hours to setup Moller and 8 hours to perform one Moller measurement.
+
  - Beam Current: 5-30 uA CW, raster always ON (5mm diameter)
−
   - Plan: we will perform one Moller measurement every (two?) week or after each beam condition change.
+
   - Set HMS:  30 deg, -3.5 GeV/c (kine 4)
 +
   - Set SHMS: 12.6 deg, -3.4 GeV/c (kine B)  
  
−
== Beam Energy Measurement ==
+
  '''Procedure for Commission Reference Cell (1 hour)'''
−
   - RC should contact MCC to organize a beam energy measurement during 1-pass running.
+
  - Move the target to Reference Cell position, make a note of gas type and pressure in each Start-Run Entry.
 +
  - Ask MCC for 5uA beam raster 5mm, note trigger rates on HMS and SHMS (write them down), stay for 2 minutes;
 +
  - Ask MCC to increase current to 10uA, 15uA, 20uA, 25uA, and 30uA, stay 2-5 minute at each current setting.
 +
  - Watch the trigger rates to make sure they roughly scales with current.
 +
  - At 30uA, take one 30-minute run.
 +
 
 +
  '''Procedure for Commission Polarized 3He Cell (1 hour)'''
 +
  - Move the target to Polarized 3He Cell position, Spin can be in any direction.
 +
  - Ask MCC for 5uA beam raster 5mm, note trigger rates on HMS and SHMS (write them down), stay for 2 minutes;
 +
  - Ask MCC to increase current to 10uA, 15uA, 20uA, 25uA, and 30uA, stay 2-5 minute at each current setting.
 +
  - Watch the trigger rates to make sure they roughly scales with current.
 +
  - At 30uA, take one 30-minute run.
 +
 
 +
== Moller Measurement (twice per week, 4-5 hours each time) ==
 +
  - Plan: we will perform Moller measurements twice a week to start with. If the polarization is stable we can do this once a week, and after each accelerator (shut)down time or beam condition change.
 +
  - Each Moller measurement takes about 8 hours and must be done during daytime on a weekday (to allow expert support).
 +
  - Note: this is a nice "time filler" to use after changing the polarized 3He cell.
 +
 
 +
  '''Procedure'''
 +
  - Ask Dave Gaskell to work his magic.
 +
 
 +
== Beam Energy Measurement (1 hour) ==
 +
   - RC should contact MCC to organize a beam energy measurement during 5-pass running. We will do it once, and after each major accelerator configuration change.
 
   - Time: 1 hour
 
   - Time: 1 hour
−
  - Plan: we will perform one beam energy measurement every (two?) week or after each beam condition change.
 
  
−
== Large Angle (30-degree) High Momentum Running (Kine 4,B) ==
+
== Large Angle (30-degree) Optics Large Angle (8 hours) ==
−
=== Large Angle (30-degree) High Momentum Running (Kine 4,B) ===
+
  '''Note'''
−
   '''Overview '''
+
  - this is a nice "time filler" to use after changing the polarized 3He cell.
−
   - We will run 42.5 (40 now?) calendar days with SHMS Kine B/HMS Kine 4;
+
  - however this has lower priority than other filler runs and should be executed last.
−
   - For each kinematic setting, a large fraction of data will be taken with longitudinal target spin, with the rest at transverse target spin;
+
 
−
   - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
+
  '''Procedure'''
−
   - We will take 1 hour of Empty Cell runs. More may be needed.
+
  - Ask Mark Jones to work his magic. His run plan is shown at [[5-pass_optics_for_A1n]]
−
   - We will take 4 hours of Reference Cell N2 runs at 8 atm;
+
 
−
   - We will take 4 hours of data with SHMS at positive polarity (should be combined with positive polarity kine C below);
+
== Large Angle (30-degree) Cross Section Study with 3He Reference Cell (4 PAC hours total)==
 +
 
 +
  '''Goals '''
 +
  - To measure 3He cross section at each kinematics.
 +
 
 +
  '''Setup'''
 +
  - Beam Current: 30uA, raster always ON (5mm diameter)
 +
  - Target:      Reference cell filled with 3He
 +
  - Detectors:    All scintillator bars ON
 +
  - Triggers: 3/4 on both HMS and SHMS
 +
 
 +
   '''Procedure'''
 +
   - Set HMS:  30 deg, -3.5 GeV/c (kine 4)
 +
  - Set SHMS: 30 deg, -3.4 GeV/c (kine B)
 +
  - Set target at Reference Cell position, make sure we have 3He in the cell and write down pressure reading in the Start-of-Run comment.
 +
  - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 +
  - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (for 30 deg we should not need to prescale at all).
 +
  - Take about three 60-min runs at this setting (goal: 300mC total charge). This assumed 8atm 3He gas pressure. If pressure is lower, scale charge goal up.
 +
  - Set HMS:  30 deg, -2.9 GeV/c (kine 3)
 +
  - Set SHMS: 30 deg, -2.6 GeV/c (kine C-modified)
 +
  - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (for 30 deg we should not need to prescale at all).
 +
   - Take one 60-min runs at this setting (goal: 100mC total charge). This assumed 8atm 3He gas pressure. If pressure is lower, scale charge goal up.
 +
 
 +
== Large Angle (30-degree) Reference Cell H2 and N2 Runs (9 PAC hours total not including magnet change) ==
 +
 
 +
  '''Goals '''
 +
  - To measure N2 and H2 cross sections at production kinematics, for dilution and nuclear correction analysis
 +
 
 +
  '''Note '''
 +
  - this is a nice "time filler" for when the polarized 3He cell is not ready for data taking, such as during a spin-up.
 +
  - we can take 1 or 2 hours of data at a time. (i.e. no need to take all at once).
 +
 +
  '''Setup'''
 +
  - Beam Current: 30uA, raster always ON (4-5mm diameter)
 +
  - Target:      Reference cell, empty, N2, H2
 +
  - Detectors:    All scintillator bars ON
 +
  - Triggers: 3/4 on both HMS and SHMS
 +
 
 +
  '''Procedure'''
 +
  - Set HMS:  30 deg, -3.5 GeV/c (kine 4)
 +
  - Set SHMS: 30 deg, -3.4 GeV/c (kine B)
 +
  - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 +
 
 +
  - Empty cell (3hr total):
 +
  - Set target at Reference Cell position;
 +
  - if the cell is **not** filled with 3He gas, vent and pump the cell to empty.
 +
  - if the cell IS filled with 3He gas, confirm with RC and/or Xiaochao first before pumping to empty.
 +
  - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take three hours data, make sure beam efficiency is high (goal: 200mC beam charge or beam on >2/3). Make a note of ref cell gas pressure in Start-Run entry.
 +
 
 +
  - N2 run (1hr total):
 +
  - Fill the reference cell with N2 gas to 10 atm.
 +
   - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take 0.5h data, make sure beam efficiency is high (goal: 33mC beam charge). Make a note of ref cell gas pressure in Start-Run entry.
 +
 
 +
  - H2 run (3hr total):
 +
  - Fill the reference cell with H2 gas to 10 atm.
 +
  - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take three hours data, make sure beam efficiency is high (goal: 200mC beam charge). Make a note of ref cell gas pressure in Start-Run entry.
 +
 
 +
  - Check if we should go back to Production. (If target polarization is high then we should!)
 +
 
 +
  - Change magnets and take runs at the following setting (4hr total for all):
 +
  - Set HMS:  30 deg, -2.9 GeV/c (kine 3)
 +
  - Set SHMS: 30 deg, -2.6 GeV/c (kine C)
 +
  - The reference cell should still have H2 in it.
 +
   - H2 run (1.5hr total):
 +
  - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take data for 90 minutes, make sure beam efficiency is high (>2/3). Make a note of ref cell gas pressure in Start-Run entry.
 +
  - Empty cell (1.5hr total):
 +
  - Vent and pump the cell to empty.
 +
   - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take data for 90 minutes, make sure beam efficiency is high (>2/3).
 +
  - N2 run (40 min):
 +
  - Fill the reference cell with N2 gas to 10 atm.
 +
   - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take one 40-min runs, make sure beam efficiency is high (>2/3). Make a note of ref cell gas pressure in Start-Run entry.
 +
 
 +
== Large Angle (30-degree) Positron Rate with SHMS (8 PAC hours plus setup)==
 +
 
 +
  '''Goal '''
 +
  - To determine pair production background (and possibly to determine its asymmetry).
 +
 
 +
  '''Setup'''
 +
  - Beam Current: 30uA, raster always ON (5mm diameter)
 +
  - Target:      Polarized 3He Cell
 +
  - Spectrometer: SHMS positive polarity (HMS can continue taking regular production data).
 +
  - EDTM: always use 120Hz pulser
 +
 
 +
  '''Spectrometer Setup'''
 +
  - SHMS positive polarity
  
−
=== Large Angle (30-degree) Low Momentum Running (Kine 3,C) ===
+
   '''Procedure'''
−
   '''Overview '''
+
   - Set target at Polarized 3He Cell position.
−
   - We will run 7.3 (6 now?) days at SHMS Kine C/HMS Kine 3;
+
   - Check and make sure all scintillator HVs are ON.
−
   - For each kinematic setting, a large fraction of data will be taken with longitudinal target spin, with the rest at transverse target spin;
+
   - Set SHMS: 30 deg, +3.4 GeV/c (kine B)
−
   - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
+
   - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (for 30 deg we should not need to prescale at all).
−
  - We will take 1 hour of Empty Cell runs. More may be needed.
+
   - Take four 60-min runs at this setting (goal: 400mC)
−
   - We will take 4 hours of Reference Cell N2 runs at 8 atm;
+
   - Make a note of # of positron after PID and window cut z=(-10,10), include this in the run list of Shift Summary.
−
   - We will take 4 hours of data with SHMS at positive polarity (should be combined with positive polarity kine B above);
 
−
   -
 
−
== Small Angle (12.5-degree) Running ==
 
  
 +
  - Set SHMS: 30 deg, +2.6 GeV/c (kine C-modified)
 +
  - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (for 30 deg we should not need to prescale at all).
 +
  - Take four 60-min runs at this setting (goal: 400mC)
 +
  - Make a note of # of positron after PID and window cut z=(-10,10), include this in the run list of Shift Summary.
  
 +
  - At the end of data taking, reverse polarity of all SHMS magnets and continue with production run (regular, electron polarity).
 +
 +
== Large Angle (30-degree) Polarized 3He Asymmetries High Momentum Setting (Kine 4,B, 511 PAC hours) ==
  
−
=== 3He Reference Cell Runs (N2 and 3He Pressure Curves) ===
 
 
   '''Goals '''
 
   '''Goals '''
−
   - To determine window background for elastic setting
+
   - To determine physics asymmetry of 3He at high x, high Q2 -- This is what we are approved beam time for!
−
  - For N2, need 5 points at 0.5, 1.0, 2, 4 and 8 atm, 10,000 N2 elastic events for each pressure setting and each spectrometer.
 
−
  - For 3He, need 5 points at 1, 2, 4, 6 and 8 atm, 10,000 3He elastic events for each pressure setting and each spectrometer.
 
−
  - Reference cell must be filled with 3He last, and do NOT pump the 3He gas out!
 
−
  - time: 2 hrs 20min total
 
  
 
   '''Setup'''
 
   '''Setup'''
−
   - Beam Current: DAQ rate-limited and up to 30uA, raster always ON (5mm diameter)
+
   - Beam Current: 30uA, raster always ON (5mm diameter)
−
   - Target:     Reference Cell, Empty, filled with N2, filled with 3He (last)
+
  - Beam IHWP:    flip roughly daily, or follow other halls. We need half data IN and half OUT for each target spin direction.
−
   - Detectors: We will need to keep only 2 SC bars ON to limit quasi-elastic scattering events.  
+
   - Target:       Polarized 3He Cell, spin in 0, 90, 180, 270 deg.
 +
   - Detectors:   All scintillator bars ON.
 +
  - EDTM: always use 120Hz pulser
 +
 
 +
  '''Time'''
 +
  - Total time: 511 PAC hours or 42.5 calendar days;
 +
  - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 +
  - Time Allocation for longitudinal spin: 82% of total (41% 0 deg, 41% 180 deg, if possible)
 +
  - Time Allocation for transverse spin: 18% of total (9% 90 deg, 9% 270 deg, if possible)
 +
 
 +
  '''Spectrometer'''
 +
  - HMS setting:  30 deg, -3.5 GeV/c (kine 4)
 +
  - SHMS setting: 30 deg, -3.4 GeV/c (kine B)
  
 
   '''Procedure'''
 
   '''Procedure'''
−
   - Set spectrometers at the required settings, target at the Reference Cell position;
+
  - Move Target to Polarized 3He Cell position.
−
   - Make sure the correct 2 SC bars are ON;
+
  - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
−
   - Pump the reference cell to empty (vacuum);
+
   - Set Target Spin at the desired direction (check with RC).
 +
  - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (we should not need to prescale at all).
 +
  - Take 60-min long runs. Do NMR at intervals specified by RC/target experts.
 +
 
 +
  '''What to Watch For'''
 +
  - Expected 3He gas rate: 0.94 Hz (HMS), 1.57 Hz (SHMS);
 +
   - Expected pi/e ratio: (2-5):1 for the worst xbj bin
 +
  - Expected total electron counts (3He gas yield N+ plus N-): 1.7M (HMS), 2.9M(SHMS)
 +
 
 +
== Large Angle (30-degree) Polarized 3He Asymmetries Low Momentum Running (Kine 3,C, 88 PAC hours) ==
 +
 
 +
  '''Goals '''
 +
  - To determine physics asymmetry of 3He at medium x, high Q2 -- overlapping and improving previous 6 GeV results
 +
 
 +
  '''Setup'''
 +
  - Beam Current: 30uA, raster always ON (5mm diameter)
 +
  - Beam IHWP:    flip roughly daily, or follow other halls. We need half data IN and half OUT for each target spin direction.
 +
  - Target:      Polarized 3He Cell, spin in 0, 90, 180, 270 deg.
 +
  - Detectors:    All scintillator bars ON.
 +
   - EDTM: always use 120Hz pulser
 
    
 
    
−
   - Take two 5-minute runs at 5 uA. Ideally this should yield 4.5kHz with PS=1. If rates are too high, lower the current but do not drop below 2uA. If rates are too low, increase current but do not exceed 30uA.
+
  '''Time'''
 +
   - Total time: 88 PAC hours or 7.3 calendar days
 +
  - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 +
  - Time Allocation for longitudinal spin: 82% of total (41% 0 deg, 41% 180 deg if possible)
 +
  - Time Allocation for transverse spin: 18% of total (9% at 90 deg, 9% at 270 deg if possible)
  
−
   - Fill Reference Cell with N2 gas to 8.0 atm, take two 5-minute runs at 2 uA. If rates are too high, prescale it down.
+
   '''Spectrometer'''
−
   - Pump the cell to 4.0 atm, take two 5-minute runs at 2 uA. If rates are too high, prescale it down.
+
   - HMS setting:  30 deg, -2.9 GeV/c (kine 3)
−
   - Pump the cell to 2.0 atm, take two 5-minute runs at 2 uA. If rates are too high, prescale it down.
+
   - SHMS setting: 30 deg, -2.6 GeV/c (kine C)  
−
  - Pump the cell (slowly) to 1.0 atm, take two 8-minute runs at 5 uA. If rates are too high, lower the current but do not drop below 2uA.
 
−
  - Pump the cell (slowly) to 0.5 atm, take two 15-minute runs at 5 uA. If rates are too high, lower the current but do not drop below 2uA.
 
  
−
   - Pump the cell to vacuum
+
   '''Procedure'''
−
   - Fill the cell to 1 atm with 3He gas, take two 5-minute runs at 5 uA. If rates are too high, lower the current but do not drop below 2uA.  
+
   - Move Target to Polarized 3He Cell position.
−
   - Fill the cell to 2 atm with 3He gas, take two 5-minute runs at 5 uA. If rates are too high, lower the current but do not drop below 2uA.  
+
   - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
−
   - Fill the cell to 4 atm with 3He gas, take two 5-minute runs at 5 uA. If rates are too high, lower the current but do not drop below 2uA.
+
   - Set Target Spin at the desired direction (check with RC).
−
   - Fill the cell to 6 atm with 3He gas, take two 5-minute runs at 4 uA. If rates are too high, lower the current but do not drop below 2uA.
+
   - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (we should not need to prescale at all).  
−
   - Fill the cell to 8 atm with 3He gas, take two 5-minute runs at 3 uA. If rates are too high, lower the current but do not drop below 2uA.
+
   - Take 60-min long runs. Do NMR at intervals specified by RC/target experts.
  
−
   - Important: After these runs are completed, do NOT pump out the 3He gas!
+
  '''What to Watch For'''
 +
   - Expected 3He gas rate: 3.4Hz (HMS), 8.2Hz (SHMS)
 +
  - Expected pi/e ratio: up to 40/1 for the worst xbj bin
 +
  - Expected total electron counts (3He gas yield N+ plus N-): 1M (HMS), 2.6M (SHMS)
  
−
  '''Things to watch for'''
+
== Small Angle Cross Section Study with 3He Reference Cell (Like, 0.5 PAC hours or 1 hour depending on beam efficiency and cell pressure)==
−
  - These reference cell runs must be taken with exactly the same spectrometer and scintillator settings as polarized 3He elastic asymmetry runs (see next)
 
−
  - For each gas pressure setting (except for empty cells), need 10,000 events from gas alone (apply ytar or ztar cuts) for each of HMS and SHMS.
 
  
−
=== Polarized 3He Elastic Longitudinal Asymmetry ===
 
 
   '''Goals '''
 
   '''Goals '''
−
   - To measure physics longitudinal asymmetry of 3He elastic scattering to (2-3)% relative, cross check PbPt from Moller and Target Polarimetry
+
   - To measure 3He cross section at each kinematics.
 +
  - We will do this only if the reference cell already has 3He gas. Otherwise no need.
  
 
   '''Setup'''
 
   '''Setup'''
−
   - Beam Current: DAQ rate-limited and up to 30uA, raster always ON (5mm diameter)
+
   - Beam Current: 10-30uA, raster always ON (5mm diameter)
−
   - HMS setting: 12.5 deg, -2.1435 GeV/c (electron)  
+
   - Target:      Reference cell filled with 8-10atm of 3He
−
   - SHMS setting: 12.5 deg, -2.1435 GeV/c (electron)  
+
  - Detectors:    All scintillator bars ON
−
   - Target:      Polarized 3He Cell, Reference Cell
+
  - Triggers: 3/4 on both HMS and SHMS
−
   - Target spin direction: 0-deg, 180-deg
+
 
−
   - Target coil settings: TBD
+
  '''Procedure'''
−
   - Detectors: We will need to keep only 2 SC bars ON to limit quasi-elastic scattering events.  
+
  - Set HMS: 11.7 deg, -6.0 GeV/c (kine 1) (Note: rotation to this small angle needs tech support)
−
   - Parity check: Inform Hall A prior to taking data to make sure they set the charge asymmetry feedback cutoff at 0.5uA.
+
   - Set SHMS: 11.0 deg, -7.1 or -6.9 GeV/c (kine D)  (Note: rotation to this small angle needs tech support)
 +
   - If using Reference Cell, make sure we have 3He in the cell and write down pressure reading in the Start-of-Run comment.
 +
   - Or use Polarized 3He Cell.
 +
   - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 +
   - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 +
  - Beam current should not be lowered below 10uA (need BCM precision).
 +
   - Take data at this setting (goal: 0.5 beam-on time. Need 1k event in x=0.83+/-0.03 bin with proper window cuts).
  
 +
  '''What to watch for'''
 +
  - Rates are DAQ-limited, expect 1/3 events from gas and 2/3 from glass windows (at 12atm). If pressure is lower (60psia=4atm) then only 10% is from 3He gas.
 +
  - Expected pi/e ratio: very low
  
 +
== Small Angle Reference Cell H2 and N2 Runs (1 PAC hour or 2 hours depending on beam efficiency) ==
 +
 +
  '''Goals '''
 +
  - To measure N2 and H2 cross sections at production kinematics, for dilution and nuclear correction analysis
 +
 +
  '''Setup'''
 +
  - Beam Current: 10-30uA, raster always ON (5mm diameter)
 +
  - Target:      Reference cell, empty, N2, H2
 +
  - Detectors:    All scintillator bars ON
 +
  - Triggers: 3/4 on both HMS and SHMS
 +
 
 
   '''Procedure'''
 
   '''Procedure'''
−
   - Set spectrometers at the required settings, target at the Reference Cell position;
+
   - Set HMS:  11.7 deg, -6.0 GeV/c (kine 1) (Note: rotation to this small angle needs tech support)
−
   - Pump the reference cell to empty (vacuum in the cell);
+
  - Set SHMS: 11.0 deg, -7.1 GeV/c (kine D)  (Note: rotation to this small angle needs tech support)
−
   - Take one 1-minute run at 1 uA, check focal plane event distribution and determine which two scintillator bars should be kept on. (expert driven).
+
  - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
−
   - Once scintillators are set, take another short run at 1uA to determine rate and prescale factor. Adjust beam current to reach close to 4.5kHz with PS=1 (but do not exceed 30uA), which means current is probably limited by SHMS rate.
+
 
−
   - Take a five-minute run or until reaching 10,000 events for both HMS and SHMS
+
  - Empty cell:
 +
  - Set target at Reference Cell position;
 +
   - if the cell is **not** filled with 3He gas, vent and pump the cell to empty.
 +
  - if the cell IS filled with 3He gas, confirm with RC and/or Xiaochao first before pumping to empty.
 +
  - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 +
  - Beam current should not be lowered below 5uA (charge asym feedback won't work).
 +
   - Take about one 20-min runs at this setting (goal: 12mC total charge or at least 40k events).
 +
 
 +
  - N2 run:
 +
  - Fill the reference cell with N2 gas to 10 atm.
 +
  - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 +
  - Beam current should not be lowered below 5uA (charge asym feedback won't work).
 +
  - Take about one 30-min runs at this setting (goal: 18mC total charge).  
 +
   - Take one 20-min run (goal: at least 40k events from N2 gas or within z from -10 to +10cm).
 +
 
 +
  - H2 run:
 +
  - Fill the reference cell with H2 gas to 10 atm.
 +
  - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 +
  - Beam current should not be lowered below 5uA (charge asym feedback won't work).
 +
  - Take about one 30-min runs at this setting (goal: 18mC total charge).
 +
  - Take one 20-min run (goal: at least 40k events from H2 gas or within z from -10 to +10cm).  
 +
 
 +
  '''What to watch for'''
 +
  - Rates are DAQ-limited, expect 1/3 events from gas and 2/3 from glass windows
 +
  - Expected pi/e ratio: very low
 +
 
 +
== Small Angle Polarized 3He Asymmetries (Kine 1,D, 84 PAC hours or 7 calendar days) ==
 +
 
 +
  '''Goals '''
 +
  - To determine physics asymmetry of 3He at low Q2 (HMS) or resonance (SHMS)
 +
 
 +
  '''Setup'''
 +
  - Beam Current: 10-30uA, raster always ON (5mm diameter)
 +
  - Beam IHWP:    flip roughly daily, or follow other halls. We need half data IN and half OUT for each target spin direction.
 +
  - Target:      Polarized 3He Cell, spin in 0, 90, 180, 270 deg.
 +
  - Detectors:    All scintillator bars ON.
 +
  - EDTM: always use 120Hz pulser
 +
 
 +
  '''Time'''
 +
  - Total time: 84 PAC hours or 7 calendar days;
 +
  - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 +
  - Time Allocation for longitudinal spin: 66% of total (33% 0 deg, 33% 180 deg, if possible)
 +
  - Time Allocation for transverse spin: 34% of total (17% 90 deg, 17% 270 deg, if possible)
 +
 
 +
 
 +
  '''Spectrometer'''
 +
  - HMS setting:  11.7 deg, -6.0 GeV/c (kine 1) (Note: moving to this small angle needs tech support)
 +
  - SHMS setting: 11.0 deg, -7.1 GeV/c (kine D)  (Note: moving to this small angle needs tech support) -> note: 6.9 GeV/c is fine too but FOM not as good.
 +
 
 +
  '''Procedure'''
 +
  - Move Target to Polarized 3He Cell position.
 +
  - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 +
  - Set Target Spin at the desired direction (check with RC).
 +
  - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS, adjust beam current and prescale for SHMS.
 +
  - Goal is to reach 3.5-4kHz DAQ rate on each of HMS and SHMS.  
 +
   - Take 60-min long runs. Do NMR at intervals specified by RC/target experts.
 +
  - Flip beam IHWP following runplan.
 +
 
 +
  '''What to watch for'''
 +
  - Rates are DAQ-limited, expect 1/3 events from gas and 2/3 from glass windows
 +
  - Expected pi/e ratio: very low
 +
  - Expected total electron counts:
 +
 
 +
== Summary of Kinematics (this may evolve with time) ==
 +
 
 +
  '''HMS'''
 +
  - Kine 1 (11.7 deg, -6.0 GeV), 84 PAC hours
 +
  - Kine 3 (30 deg, -2.9 GeV), 88 PAC hours
 +
  - Kine 4 (30 deg, -3.5 GeV), 511 PAC hours
 +
 
 +
  '''SHMS'''
 +
  - Kine B (30 deg, -3.4 GeV), 511 PAC hours
 +
  - Kine C (30 deg, -2.6 GeV), 88 PAC hours
 +
  - Kine D (11.0 deg, -7.1 GeV), 84 PAC hours
  
 +
  '''Positron runs'''
 +
  - SHMS only, use Pol3He cell or 3He Ref Cell (if available)
 +
  - 4 hour at SHMS Kine B
 +
  - 4 hour at SHMS Kine C
  
 +
  '''Reference cell runs'''
 +
  - see runplan above
  
−
   - Move target to Polarized 3He Cell position, spin polarization at either 0 or 180 degrees.
+
   '''Timeline overview (focused on production)'''
−
   - Perform one polarimetry measurement before taking data.
+
   - HMS and SHMS parallel in kinematics: 600 PAC hours
−
   - Make sure the same two SC bars are on as the Reference Cell,  
+
   - HMS at Kine 4 (30 deg, -3.5 GeV), SHMS at Kine B (30 deg, -3.4 GeV), 511 PAC hours, 82% long 18% trans
−
  - Take one 1-minute run at 1 uA, check focal plane event distribution and determine which two scintillator bars should be kept on. (expert driven).
+
   - HMS at Kine 3 (30 deg, -2.9 GeV), SHMS at Kine C (30 deg, -2.6 GeV), 88 PAC hours, 82% long 18% trans
−
  - Once scintillators are set, take one 1-minute run at 2uA, adjust beam current to reach 4.5kHz on HMS with PS=1. For SHMS likely need PS>1 to keep DAQ rate within limit.
+
   - HMS and SHMS not parallel in kinematics: 84 PAC hours
−
   - Take four 30-minute runs, perform one polarimetry measurement after each run. Verify data quality (see below) and verify target is still polarized.
+
   - HMS at Kine 1 (11.7 deg, -6.0 GeV), SHMS at Kine D (11.0 deg, -7.1 GeV preferred or -6.9 GeV Ok), 84 PAC hours, 66% long 34% trans (average of optimization between the two)
−
  - Rotate target spin direction from 0 to 180 deg (or from 180 to 0 deg)
 
−
  - Take four 30-minute runs, perform one polarimetry measurement after each run. Verify data quality (see below) and verify target is still polarized.
 
−
   - Call MCC and ask beam IHWP to be inserted (or taken out). Need to inform other halls prior to the switch.
 
−
   - Take four 30-minute runs, perform one polarimetry measurement after each run. Verify data quality (see below) and verify target is still polarized.
 
−
  - Rotate target spin direction from 0 to 180 deg (or from 180 to 0 deg)
 
−
  - Take four 30-minute runs, perform one polarimetry measurement after each run. Verify data quality (see below) and verify target is still polarized.
 
  
 +
== Online/Expert Analysis Requirement ==
  
−
   '''Things to watch online'''
+
   '''Things to Watch For'''
−
   - Ensure the correct SC bars are on (We need elastic events! One SC bar is in principle enough but we keep TWO on)
+
   - Check PID, we need only electrons. Pion backgrounds may be high.
−
   - Apply y or z cuts to isolate events scattered from 3He gas (We do not want events from the glass windows!)
+
   - Check ztar distribution to check if cuts are necessary to reject glass windows. Electron yield should be extracted for 3He gas only.
−
   - Apply W cuts to isolate elastic events from others.
+
  - Please use the following xbj bins, extract N+ N- and yield per charge N+/Q+ N-/Q- cumulated over this kinematics, and calculate asymmetries for N/Q.
−
   - Run online script to ensure we see physics asymmetry. HMS and SHMS should see the same asymmetry. Asymmetry should flip sign with beam IHWP switch and target spin flip.
+
   - xbj bin centers: 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.71,0.77,0.83,0.89,0.95,1.00
 +
   - xbj bin widths:  0.025,0.025,0.025,0.025,0.025,0.025,0.025,0.025,0.025,0.03,0.03,0.03,0.03,0.03,0.03
 +
  - Please record W and Xbj distributions, cumulated N+ N-, x-binned cumulated N+ N-, x-binned cumulated asymmetries per day.
  
−
   - Expected total rate: (To be updated)
+
  '''Calculations and Analysis posts'''
−
   - Expected asymmetries (after W and Ytg cuts): Aphys=5.8% Ameas=2.3% if using Pt=50%, Pb=85%, N2 dilution 0.92.
+
   - Expected cross sections, rates, etc: https://logbooks.jlab.org/entry/3766085
−
   - Expected uncertainties dA/A=2% (goal) or 3% (minimum).
+
   - Typical HMS  online plots: https://logbooks.jlab.org/entry/3764835
 +
   - Typical SHMS online monitoring plots: https://logbooks.jlab.org/entry/3764834

Latest revision as of 16:58, 13 February 2020

Overview

For polarized 3He running in Fall 2019 and Spring 2020, the nominal raster for production is 5mm diameter circular. The nominal triggers used are 3/4 for both HMS and SHMS. Both HMS and SHMS should be taking data (for example if run plan specify one run, it means one run on HMS and one run on SHMS simultaneously). No coincidence trigger will be used/setup.

Polarized_Helium-3_Experiments#Run_Plan <- click this to return to main run plan page

Beam and raster checkout

 Please refer to Beam and Raster Checkout for A1n/d2n (Short Procedure).
 Or Beam and Raster Checkout for A1n/d2n (Long Procedure).

BCM Calibration

 Goals 
 - BCM Calibration

 Procedure
 - Follow draft instructions here: Non-invasive BCM calibration procedure for 3He running 2019-2020
 - Per Dave G.'s request please add two more points below 1uA, for example 0.5uA and 0.8uA.

Glass Cell Current Scan/Checkout and Commissioning

 Goals 
 - Make sure we can put 30 uA of beam on the glass cells (Reference cell, Polarized 3He cell).
 - Jianping must be present.

 Setup
 - Beam Current: 5-30 uA CW, raster always ON (5mm diameter)
 - Set HMS:  30 deg, -3.5 GeV/c (kine 4)
 - Set SHMS: 12.6 deg, -3.4 GeV/c (kine B) 

 Procedure for Commission Reference Cell (1 hour)
 - Move the target to Reference Cell position, make a note of gas type and pressure in each Start-Run Entry.
 - Ask MCC for 5uA beam raster 5mm, note trigger rates on HMS and SHMS (write them down), stay for 2 minutes;
 - Ask MCC to increase current to 10uA, 15uA, 20uA, 25uA, and 30uA, stay 2-5 minute at each current setting. 
 - Watch the trigger rates to make sure they roughly scales with current.
 - At 30uA, take one 30-minute run.

 Procedure for Commission Polarized 3He Cell (1 hour)
 - Move the target to Polarized 3He Cell position, Spin can be in any direction.
 - Ask MCC for 5uA beam raster 5mm, note trigger rates on HMS and SHMS (write them down), stay for 2 minutes;
 - Ask MCC to increase current to 10uA, 15uA, 20uA, 25uA, and 30uA, stay 2-5 minute at each current setting. 
 - Watch the trigger rates to make sure they roughly scales with current.
 - At 30uA, take one 30-minute run.

Moller Measurement (twice per week, 4-5 hours each time)

 - Plan: we will perform Moller measurements twice a week to start with. If the polarization is stable we can do this once a week, and after each accelerator (shut)down time or beam condition change.
 - Each Moller measurement takes about 8 hours and must be done during daytime on a weekday (to allow expert support).
 - Note: this is a nice "time filler" to use after changing the polarized 3He cell. 
 
 Procedure
 - Ask Dave Gaskell to work his magic.

Beam Energy Measurement (1 hour)

 - RC should contact MCC to organize a beam energy measurement during 5-pass running. We will do it once, and after each major accelerator configuration change.
 - Time: 1 hour

Large Angle (30-degree) Optics Large Angle (8 hours)

 Note
 - this is a nice "time filler" to use after changing the polarized 3He cell. 
 - however this has lower priority than other filler runs and should be executed last.
 
 Procedure
 - Ask Mark Jones to work his magic. His run plan is shown at 5-pass_optics_for_A1n

Large Angle (30-degree) Cross Section Study with 3He Reference Cell (4 PAC hours total)

 Goals 
 - To measure 3He cross section at each kinematics. 

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:       Reference cell filled with 3He
 - Detectors:    All scintillator bars ON
 - Triggers: 3/4 on both HMS and SHMS
 
 Procedure
 - Set HMS:  30 deg, -3.5 GeV/c (kine 4)
 - Set SHMS: 30 deg, -3.4 GeV/c (kine B) 
 - Set target at Reference Cell position, make sure we have 3He in the cell and write down pressure reading in the Start-of-Run comment. 
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (for 30 deg we should not need to prescale at all). 
 - Take about three 60-min runs at this setting (goal: 300mC total charge). This assumed 8atm 3He gas pressure. If pressure is lower, scale charge goal up. 
 - Set HMS:  30 deg, -2.9 GeV/c (kine 3)
 - Set SHMS: 30 deg, -2.6 GeV/c (kine C-modified) 
 - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (for 30 deg we should not need to prescale at all). 
 - Take one 60-min runs at this setting (goal: 100mC total charge). This assumed 8atm 3He gas pressure. If pressure is lower, scale charge goal up.

Large Angle (30-degree) Reference Cell H2 and N2 Runs (9 PAC hours total not including magnet change)

 Goals 
 - To measure N2 and H2 cross sections at production kinematics, for dilution and nuclear correction analysis

 Note 
 - this is a nice "time filler" for when the polarized 3He cell is not ready for data taking, such as during a spin-up.
 - we can take 1 or 2 hours of data at a time. (i.e. no need to take all at once).

 Setup
 - Beam Current: 30uA, raster always ON (4-5mm diameter)
 - Target:       Reference cell, empty, N2, H2
 - Detectors:    All scintillator bars ON
 - Triggers: 3/4 on both HMS and SHMS
 
 Procedure
 - Set HMS:  30 deg, -3.5 GeV/c (kine 4)
 - Set SHMS: 30 deg, -3.4 GeV/c (kine B) 
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).

 - Empty cell (3hr total):
 - Set target at Reference Cell position;
 - if the cell is **not** filled with 3He gas, vent and pump the cell to empty.
 - if the cell IS filled with 3He gas, confirm with RC and/or Xiaochao first before pumping to empty.
 - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all). 
 - Take three hours data, make sure beam efficiency is high (goal: 200mC beam charge or beam on >2/3). Make a note of ref cell gas pressure in Start-Run entry.

 - N2 run (1hr total):
 - Fill the reference cell with N2 gas to 10 atm.
 - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all). 
 - Take 0.5h data, make sure beam efficiency is high (goal: 33mC beam charge). Make a note of ref cell gas pressure in Start-Run entry.

 - H2 run (3hr total):
 - Fill the reference cell with H2 gas to 10 atm.
 - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all). 
 - Take three hours data, make sure beam efficiency is high (goal: 200mC beam charge). Make a note of ref cell gas pressure in Start-Run entry.

 - Check if we should go back to Production. (If target polarization is high then we should!)

 - Change magnets and take runs at the following setting (4hr total for all):
 - Set HMS:  30 deg, -2.9 GeV/c (kine 3) 
 - Set SHMS: 30 deg, -2.6 GeV/c (kine C) 
 - The reference cell should still have H2 in it.
 - H2 run (1.5hr total):
 - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (we should not need to prescale at all). 
 - Take data for 90 minutes, make sure beam efficiency is high (>2/3). Make a note of ref cell gas pressure in Start-Run entry.
 - Empty cell (1.5hr total):
 - Vent and pump the cell to empty.
 - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all). 
 - Take data for 90 minutes, make sure beam efficiency is high (>2/3).
 - N2 run (40 min):
 - Fill the reference cell with N2 gas to 10 atm.
 - Ask for 30uA raster ON, use 3/4 triggers, check rates and set prescale factors (we should not need to prescale at all). 
 - Take one 40-min runs, make sure beam efficiency is high (>2/3). Make a note of ref cell gas pressure in Start-Run entry.

Large Angle (30-degree) Positron Rate with SHMS (8 PAC hours plus setup)

 Goal 
 - To determine pair production background (and possibly to determine its asymmetry).

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:       Polarized 3He Cell
 - Spectrometer: SHMS positive polarity (HMS can continue taking regular production data).
 - EDTM: always use 120Hz pulser
 
 Spectrometer Setup
 - SHMS positive polarity

 Procedure
 - Set target at Polarized 3He Cell position.
 - Check and make sure all scintillator HVs are ON.
 - Set SHMS: 30 deg, +3.4 GeV/c (kine B) 
 - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (for 30 deg we should not need to prescale at all). 
 - Take four 60-min runs at this setting (goal: 400mC)
 - Make a note of # of positron after PID and window cut z=(-10,10), include this in the run list of Shift Summary.

 - Set SHMS: 30 deg, +2.6 GeV/c (kine C-modified) 
 - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (for 30 deg we should not need to prescale at all). 
 - Take four 60-min runs at this setting (goal: 400mC)
 - Make a note of # of positron after PID and window cut z=(-10,10), include this in the run list of Shift Summary.

 - At the end of data taking, reverse polarity of all SHMS magnets and continue with production run (regular, electron polarity).

Large Angle (30-degree) Polarized 3He Asymmetries High Momentum Setting (Kine 4,B, 511 PAC hours)

 Goals 
 - To determine physics asymmetry of 3He at high x, high Q2 -- This is what we are approved beam time for!

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Beam IHWP:    flip roughly daily, or follow other halls. We need half data IN and half OUT for each target spin direction.
 - Target:       Polarized 3He Cell, spin in 0, 90, 180, 270 deg.
 - Detectors:    All scintillator bars ON. 
 - EDTM: always use 120Hz pulser
 
 Time
 - Total time: 511 PAC hours or 42.5 calendar days;
 - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 - Time Allocation for longitudinal spin: 82% of total (41% 0 deg, 41% 180 deg, if possible)
 - Time Allocation for transverse spin: 18% of total (9% 90 deg, 9% 270 deg, if possible)

 Spectrometer
 - HMS setting:  30 deg, -3.5 GeV/c (kine 4)
 - SHMS setting: 30 deg, -3.4 GeV/c (kine B) 

 Procedure
 - Move Target to Polarized 3He Cell position.
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 - Set Target Spin at the desired direction (check with RC).
 - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (we should not need to prescale at all). 
 - Take 60-min long runs. Do NMR at intervals specified by RC/target experts.

 What to Watch For
 - Expected 3He gas rate: 0.94 Hz (HMS), 1.57 Hz (SHMS);
 - Expected pi/e ratio: (2-5):1 for the worst xbj bin
 - Expected total electron counts (3He gas yield N+ plus N-): 1.7M (HMS), 2.9M(SHMS)

Large Angle (30-degree) Polarized 3He Asymmetries Low Momentum Running (Kine 3,C, 88 PAC hours)

 Goals 
 - To determine physics asymmetry of 3He at medium x, high Q2 -- overlapping and improving previous 6 GeV results

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Beam IHWP:    flip roughly daily, or follow other halls. We need half data IN and half OUT for each target spin direction.
 - Target:       Polarized 3He Cell, spin in 0, 90, 180, 270 deg.
 - Detectors:    All scintillator bars ON. 
 - EDTM: always use 120Hz pulser
 
 Time
 - Total time: 88 PAC hours or 7.3 calendar days
 - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 - Time Allocation for longitudinal spin: 82% of total (41% 0 deg, 41% 180 deg if possible)
 - Time Allocation for transverse spin: 18% of total (9% at 90 deg, 9% at 270 deg if possible)

 Spectrometer
 - HMS setting:  30 deg, -2.9 GeV/c (kine 3)
 - SHMS setting: 30 deg, -2.6 GeV/c (kine C) 

 Procedure
 - Move Target to Polarized 3He Cell position.
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 - Set Target Spin at the desired direction (check with RC).
 - Ask for 30uA raster ON, use 3/4 triggers only, check rates and set prescale factors (we should not need to prescale at all). 
 - Take 60-min long runs. Do NMR at intervals specified by RC/target experts.

 What to Watch For
 - Expected 3He gas rate: 3.4Hz (HMS), 8.2Hz (SHMS)
 - Expected pi/e ratio: up to 40/1 for the worst xbj bin
 - Expected total electron counts (3He gas yield N+ plus N-): 1M (HMS), 2.6M (SHMS)

Small Angle Cross Section Study with 3He Reference Cell (Like, 0.5 PAC hours or 1 hour depending on beam efficiency and cell pressure)

 Goals 
 - To measure 3He cross section at each kinematics. 
 - We will do this only if the reference cell already has 3He gas. Otherwise no need.

 Setup
 - Beam Current: 10-30uA, raster always ON (5mm diameter)
 - Target:       Reference cell filled with 8-10atm of 3He
 - Detectors:    All scintillator bars ON
 - Triggers: 3/4 on both HMS and SHMS
 
 Procedure
 - Set HMS:  11.7 deg, -6.0 GeV/c (kine 1) (Note: rotation to this small angle needs tech support)
 - Set SHMS: 11.0 deg, -7.1 or -6.9 GeV/c (kine D)  (Note: rotation to this small angle needs tech support)
 - If using Reference Cell, make sure we have 3He in the cell and write down pressure reading in the Start-of-Run comment. 
 - Or use Polarized 3He Cell.
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 - Beam current should not be lowered below 10uA (need BCM precision).
 - Take data at this setting (goal: 0.5 beam-on time. Need 1k event in x=0.83+/-0.03 bin with proper window cuts).

 What to watch for
 - Rates are DAQ-limited, expect 1/3 events from gas and 2/3 from glass windows (at 12atm). If pressure is lower (60psia=4atm) then only 10% is from 3He gas.
 - Expected pi/e ratio: very low

Small Angle Reference Cell H2 and N2 Runs (1 PAC hour or 2 hours depending on beam efficiency)

 Goals 
 - To measure N2 and H2 cross sections at production kinematics, for dilution and nuclear correction analysis

 Setup
 - Beam Current: 10-30uA, raster always ON (5mm diameter)
 - Target:       Reference cell, empty, N2, H2
 - Detectors:    All scintillator bars ON
 - Triggers: 3/4 on both HMS and SHMS
 
 Procedure
 - Set HMS:  11.7 deg, -6.0 GeV/c (kine 1) (Note: rotation to this small angle needs tech support)
 - Set SHMS: 11.0 deg, -7.1 GeV/c (kine D)  (Note: rotation to this small angle needs tech support)
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).

 - Empty cell:
 - Set target at Reference Cell position;
 - if the cell is **not** filled with 3He gas, vent and pump the cell to empty.
 - if the cell IS filled with 3He gas, confirm with RC and/or Xiaochao first before pumping to empty.
 - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 - Beam current should not be lowered below 5uA (charge asym feedback won't work).
 - Take about one 20-min runs at this setting (goal: 12mC total charge or at least 40k events). 

 - N2 run:
 - Fill the reference cell with N2 gas to 10 atm.
 - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 - Beam current should not be lowered below 5uA (charge asym feedback won't work).
 - Take about one 30-min runs at this setting (goal: 18mC total charge). 
 - Take one 20-min run (goal: at least 40k events from N2 gas or within z from -10 to +10cm). 

 - H2 run:
 - Fill the reference cell with H2 gas to 10 atm.
 - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS and adjust beam current and prescale for SHMS to reach 4kHz DAQ rate each.
 - Beam current should not be lowered below 5uA (charge asym feedback won't work).
 - Take about one 30-min runs at this setting (goal: 18mC total charge). 
 - Take one 20-min run (goal: at least 40k events from H2 gas or within z from -10 to +10cm). 

 What to watch for
 - Rates are DAQ-limited, expect 1/3 events from gas and 2/3 from glass windows 
 - Expected pi/e ratio: very low

Small Angle Polarized 3He Asymmetries (Kine 1,D, 84 PAC hours or 7 calendar days)

 Goals 
 - To determine physics asymmetry of 3He at low Q2 (HMS) or resonance (SHMS) 

 Setup
 - Beam Current: 10-30uA, raster always ON (5mm diameter)
 - Beam IHWP:    flip roughly daily, or follow other halls. We need half data IN and half OUT for each target spin direction.
 - Target:       Polarized 3He Cell, spin in 0, 90, 180, 270 deg.
 - Detectors:    All scintillator bars ON. 
 - EDTM: always use 120Hz pulser
 
 Time
 - Total time: 84 PAC hours or 7 calendar days;
 - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 - Time Allocation for longitudinal spin: 66% of total (33% 0 deg, 33% 180 deg, if possible)
 - Time Allocation for transverse spin: 34% of total (17% 90 deg, 17% 270 deg, if possible)



 Spectrometer
 - HMS setting:  11.7 deg, -6.0 GeV/c (kine 1) (Note: moving to this small angle needs tech support)
 - SHMS setting: 11.0 deg, -7.1 GeV/c (kine D)  (Note: moving to this small angle needs tech support) -> note: 6.9 GeV/c is fine too but FOM not as good.

 Procedure
 - Move Target to Polarized 3He Cell position.
 - Check and make sure all scintillator HVs are ON (both HMS and SHMS).
 - Set Target Spin at the desired direction (check with RC).
 - Ask for 10uA raster ON, use 3/4 triggers, set prescale=1 for HMS, adjust beam current and prescale for SHMS. 
 - Goal is to reach 3.5-4kHz DAQ rate on each of HMS and SHMS. 
 - Take 60-min long runs. Do NMR at intervals specified by RC/target experts.
 - Flip beam IHWP following runplan.

 What to watch for
 - Rates are DAQ-limited, expect 1/3 events from gas and 2/3 from glass windows 
 - Expected pi/e ratio: very low
 - Expected total electron counts:

Summary of Kinematics (this may evolve with time)

 HMS
 - Kine 1 (11.7 deg, -6.0 GeV), 84 PAC hours
 - Kine 3 (30 deg, -2.9 GeV), 88 PAC hours
 - Kine 4 (30 deg, -3.5 GeV), 511 PAC hours

 SHMS
 - Kine B (30 deg, -3.4 GeV), 511 PAC hours
 - Kine C (30 deg, -2.6 GeV), 88 PAC hours
 - Kine D (11.0 deg, -7.1 GeV), 84 PAC hours

 Positron runs
 - SHMS only, use Pol3He cell or 3He Ref Cell (if available)
 - 4 hour at SHMS Kine B
 - 4 hour at SHMS Kine C

 Reference cell runs
 - see runplan above

 Timeline overview (focused on production)
 - HMS and SHMS parallel in kinematics: 600 PAC hours
 - HMS at Kine 4 (30 deg, -3.5 GeV), SHMS at Kine B (30 deg, -3.4 GeV), 511 PAC hours, 82% long 18% trans
 - HMS at Kine 3 (30 deg, -2.9 GeV), SHMS at Kine C (30 deg, -2.6 GeV), 88 PAC hours, 82% long 18% trans
 - HMS and SHMS not parallel in kinematics: 84 PAC hours 
 - HMS at Kine 1 (11.7 deg, -6.0 GeV), SHMS at Kine D (11.0 deg, -7.1 GeV preferred or -6.9 GeV Ok), 84 PAC hours, 66% long 34% trans (average of optimization between the two)

Online/Expert Analysis Requirement

 Things to Watch For
 - Check PID, we need only electrons. Pion backgrounds may be high.
 - Check ztar distribution to check if cuts are necessary to reject glass windows. Electron yield should be extracted for 3He gas only.
 - Please use the following xbj bins, extract N+ N- and yield per charge N+/Q+ N-/Q- cumulated over this kinematics, and calculate asymmetries for N/Q.
 - xbj bin centers: 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.71,0.77,0.83,0.89,0.95,1.00
 - xbj bin widths:  0.025,0.025,0.025,0.025,0.025,0.025,0.025,0.025,0.025,0.03,0.03,0.03,0.03,0.03,0.03
 - Please record W and Xbj distributions, cumulated N+ N-, x-binned cumulated N+ N-, x-binned cumulated asymmetries per day.

 Calculations and Analysis posts
 - Expected cross sections, rates, etc: https://logbooks.jlab.org/entry/3766085
 - Typical HMS  online plots: https://logbooks.jlab.org/entry/3764835
 - Typical SHMS online monitoring plots: https://logbooks.jlab.org/entry/3764834
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