5-pass production for A1n

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