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, 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

Beam and raster checkout

 Please refer to 2-pass commissioning procedure, follow:
 - Establish beam in the hall
 - Initial Raster checks
 - Harp scans
 - Target/Beam centering, Raster calibration

Moller Measurement

 - Will need 8 hours to setup Moller and 8 hours to perform one Moller measurement.
 - Plan: we will perform one Moller measurement every (two?) week or after each beam condition change.

Beam Energy Measurement

 - RC should contact MCC to organize a beam energy measurement during 1-pass running.
 - Time: 1 hour
 - Plan: we will perform one beam energy measurement every (two?) week or after each beam condition change.

Production Large Angle (30-degree) Running

 Things to Watch For in Online Analysis
 - Check PID, we need only electrons. Pion backgrounds may be high.
 - Check ytar or ztar distribution to check if cuts are necessary to reject glass windows. Electron yield should be extracted for 3He gas only.
 - Post W and Xbj distributions per day.
 - Asymmetry will flip sign for each target spin and beam IHWP reversal.
 - Please extract yield per charge, helicity-dependent yield N+ N- cumulated over this kinematics, and calculate asymmetries.

Large Angle (30-degree) High Momentum Running (Kine 4,B)

 Overview 
 - We will run 42.5 (40 now?) calendar days with SHMS Kine B/HMS Kine 4;
 - For this setting, 82% of data will be taken with longitudinal target spin, 18% at transverse target spin;
 - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
 - We will take 1 hour of Empty Cell runs. More may be needed.
 - 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);

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:      Polarized 3He Cell, Reference Cell -- Empty, filled with N2, filled with 3He
 - HMS (Kine 4):  30.0 deg, 3.5 GeV/c (electron)
 - SHMS (Kine B): 30.0 deg, 3.4 GeV/c (electron) except for positive polarity running
 - Detectors:  All SC bars ON

 Procedure
 - Need to fill in frequency of target polarimetry measurements, nominal time for each run, frequency to flip beam IHWP and target spin directions (ideally we want to have all 4 combinations for each 24 hours of beam).

 - 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) Low Momentum Running (Kine 3,C)

 Overview 
 - We will run 7.3 (6 now?) days at SHMS Kine C/HMS Kine 3;
 - For this setting, 82% of data will be taken with longitudinal target spin, 18% at transverse target spin;
 - Beam IHWP and Target Spin should be flipped routinely, providing same statistics for ++, +-, -+ and -- configurations;
 - We will take 1 hour of Empty Cell runs. More may be needed.
 - 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 B above);

 Setup
 - Beam Current: 30uA, raster always ON (5mm diameter)
 - Target:      Polarized 3He Cell, Reference Cell -- Empty, filled with N2, filled with 3He
 - HMS (Kine 3):  30.0 deg, 2.9 GeV/c (electron)
 - SHMS (Kine C): 30.0 deg, 2.4 GeV/c (electron) except for positive polarity running
 - Detectors:  All SC bars ON

 Procedure

 - 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 (12.5-degree) Running

 Things to Watch For in Online Analysis
 - Check PID, we need only electrons. Pion backgrounds may be high.
 - Check ytar or ztar distribution to check if cuts are necessary to reject glass windows. Electron yield should be extracted for 3He gas only.
 - Check W distribution, should be smooth (DIS).
 - Asymmetry will flip sign for each target spin and beam IHWP reversal.
 - Please extract yield per charge, helicity-dependent yield N+ N- cumulated over this kinematics, and calculate asymmetries.

HMS 12.5 deg Low Momentum (HMS Kine 1)

 Overview 
 - We will run 2 days plus two shifts at HMS Kine 1;
 - For this setting, 75% of data will be taken with longitudinal target spin, 25% at transverse target spin;
 - 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
 - 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

HMS 12.5 deg High Momentum (HMS Kine 2)

 Overview 
 - We will run 5 days plus one shift at HMS Kine 2;
 - For this setting, 72% of data will be taken with longitudinal target spin, 28% at transverse target spin;
 - 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
 - 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

SHMS Resonance (Kine D)

 Overview 
 - We will run 8 days at SHMS Kine D;
 - For this setting, 72% of data will be taken with longitudinal target spin, 28% at transverse target spin;
 - 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
 - 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