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.

For 5-pass production of A1n at large angle, there are two settings each for HMS (3,4) and SHMS (B,C). For each setting, we will take data on polarized 3He cell, a few hours on reference cell (both N2 and 3He), and need 1 hour of positive polarity runs on SHMS per setting.

For 5-pass production of A1n at large angle, we will also need 8 hours of optics data. May want to save this for when cell change is needed.

For 5-pass production of A1n at small angle, there are two settings for HMS (1,2) and one for SHMS (D). For each setting, we will take data on polarized 3He cell, a few hours on reference cell (both N2 and 3He). No positive polarity runs will be needed.

We will need Moller measurements throughout the production running, preferrably every two weeks and after each accelerator condition change. May want to save this for when cell change is needed.

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).

Moller Measurement

 - 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

 - 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

Rate study with 3He Reference Cell or Polarized 3He Cell

 Goals 
 - To have a quick survey of production rates at each kinematics. Data will also be used to determine/cross check 3He cross sections.

 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. 
 - If the Reference Cell is not filled with 3He, can do this study with polarized 3He cell. In this case move target to Polarized 3He Cell position.
 - 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 one 60-min runs at this setting, then change to next setup:
 - Set HMS:  30 deg, -2.9 GeV/c (kine 3)
 - Set SHMS: 30 deg, -2.4 GeV/c (kine C) 
 - 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.

Reference Cell H2 and N2 Runs

 Goals 
 - To measure N2 and H2 cross sections at production kinematics.

 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 (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).
 - Set target at Reference Cell position, if the cell is not filled with 3He gas, 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 one 60-min run.
 - 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 or two 60-min runs. Make a note of ref cell gas pressure in Start-Run entry.
 - (total 8 hours on N2 is needed, but we do not need to take them all at once).
 - Make a note of # of electrons after applying PID and window cut z=(-10,10) in the run list in the Shift Summary.
 - 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 one or two 60-min runs. Make a note of ref cell gas pressure in Start-Run entry.
 - Make sure we have 10k electron events after applying PID and window cut z=(-10,10). 

 - Set HMS:  30 deg, -2.9 GeV/c (kine 3)
 - Set SHMS: 30 deg, -2.4 GeV/c (kine C) 
 - The reference cell should still have H2 in it.
 - 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 one or two 60-min runs at this setting. Make a note of ref cell gas pressure in Start-Run entry.
 - Make sure we have 10k electron events after applying PID and window cut z=(-10,10). 
 - 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 or two 60-min runs. Make a note of ref cell gas pressure in Start-Run entry.
 - (total 8 hours on N2 is needed, but we do not need to take them all at once).
 - Make a note of # of electrons after applying PID and window cut z=(-10,10) in the run list in the Shift Summary.

Positron Rate with SHMS

 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).
 
 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
 - 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, +2.4 GeV/c (kine C) 
 - 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.
 - 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).

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

 Goals 
 - To determine physics asymmetry of 3He at high x -- 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. 
 
 Time
 - Total time: 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 (17 days 0 deg, 17 days 180 deg)
 - Time Allocation for transverse spin: 18% of total (3.8 days at 90 deg, 3.8 days at 270 deg)

 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 every two hours.

 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)

Production Large Angle (30-degree) Low Momentum Running (Kine 3,C)

 Goals 
 - To determine physics asymmetry of 3He at high x -- 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. 
 
 Time
 - Total time: 7.3 calendar days;
 - Beam IHWP and Target Spin should be flipped routinely, providing equal statistics for ++, +-, -+ and -- configurations;
 - Time Allocation for longitudinal spin: 80% of total (70 hours 0 deg, 70 hours 180 deg)
 - Time Allocation for transverse spin: 20% of total (18 hours at 90 deg, 18 hours at 270 deg)

 Spectrometer
 - HMS setting:  30 deg, -2.9 GeV/c (kine 3)
 - SHMS setting: 30 deg, -2.4 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 every two hours.

 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)

Production Small angle (12.5 deg) HMS Low Momentum (HMS Kine 1) -- to do later

 Overview 
 - We will run 2 days plus two shifts at HMS Kine 1;
 - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
 - We will take 1 hour of Empty Cell runs. 
 - We will take 2 hours of Reference Cell N2 runs at 8 atm;

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:      Polarized 3He Cell, Reference Cell -- Empty, filled with N2, filled with 3He
 - Pol3He Target Spin: 75% of data at longitudinal (0 and 180 deg), 25% at transverse (90 and 270 deg) spin;
 - HMS:  12.5 deg, 5.7 GeV/c (electron)
 - SHMS: should be at kine D (see below)
 - Detectors:  All SC bars ON

 Procedure
 - Expected 3He gas rate: 880Hz
 - Expected pi/e ratio: less than 1/1
 - Expected total electron counts (3He gas yield N+ plus N-): 101M

Production Small angle (12.5 deg) HMS Low Momentum (HMS Kine 2) -- to do later

 Overview 
 - We will run 5 days plus one shift at HMS Kine 2;
 - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
 - We will take 1 hour of Empty Cell runs. 
 - We will take 2 hours of Reference Cell N2 runs at 8 atm;

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:      Polarized 3He Cell, Reference Cell -- Empty, filled with N2, filled with 3He
 - Pol3He Target Spin: 72% of data at longitudinal (0 and 180 deg), 28% at transverse (90 and 270 deg) spin;
 - HMS:  12.5 deg, 6.8 GeV/c (electron)
 - SHMS: should be at kine D (see below)
 - Detectors:  All SC bars ON

 Procedure
 - Expected 3He gas rate: 500Hz
 - Expected pi/e ratio: low (<1/1)
 - Expected total electron counts (3He gas yield N+ plus N-): 115M

Production Small angle (12.5 deg) SHMS Resonance (SHMS Kine D) -- to do later

 Overview 
 - We will run 8 days at SHMS Kine D;
 - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
 - We will take 1 hour of Empty Cell runs. 
 - We will take 2 hours of Reference Cell N2 runs at 8 atm;

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:      Polarized 3He Cell, Reference Cell -- Empty, filled with N2, filled with 3He
 - Since this setting is concurrent with HMS Kine 1 and 2, target spin should follow instructions for HMS Kine 1 and 2 above.
 - SHMS: 12.5 deg, 7.5 GeV/c (electron)
 - Detectors:  All SC bars ON

 Procedure
 - Expected 3He gas rate: 185Hz
 - Expected pi/e ratio: very low
 - Expected total electron counts (3He gas yield N+ plus N-): 64M

Summary of Reference Cell Runs needed (-- to do later)

 - For planning purposes it is useful to list all reference cell runs here.  The following proposed times are from the 2010 proposal. Time listed are in calendar hours (twice the PAC hour in the proposal. That is, "BEAM ON" time should be half the values below).
 - Analysis requirement are the same as polarized 3He target data.

 - N2 Reference Cell runs to check the dilution factor for each kinematics. Need 8-10atm N2 Reference Cell.
 - 4 hours at HMS Kine 1 (12.5 deg, -5.7 GeV)
 - 4 hours at HMS Kine 2 (12.5 deg, -6.8 GeV)
 - 8 hours at HMS kine 3 (30 deg, -2.9 GeV)
 - 8 hours at HMS Kine 4 (30 deg, -3.5 GeV)
 - 8 hours at SHMS Kine B (30 deg, -3.4 GeV)
 - 8 hours at SHMS Kine C (30 deg, -2.4 GeV)
 - 4 hours at SHMS Kine D (12.5 deg, -7.5 GeV)

 - Positron runs to check e+/e- background. Need 8-10atm 3He Reference Cell.
 - Possibly using 3He Reference Cell will be good enough. Depending on how difficult it is to change polarity, we need only positron runs on SHMS (HMS is optional)
 - 2 hour at SHMS Kine B (and HMS Kine 4)
 - 2 hour at SHMS Kine C (and HMS Kine 3)

Online/Expert Analysis Requirement

 Things to Watch For in Online Analysis
 - 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.
 - Asymmetry will flip sign for each target spin and beam IHWP reversal.
 - Please extract yield per charge, helicity-dependent charge Q+ Q- and yield N+ N- cumulated over this kinematics.
 - 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 post W and Xbj distributions, cumulated N+ N-, x-binned cumulated N+ N-, x-binned cumulated asymmetries per day.