5-pass production for A1n
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Revision as of 15:37, 21 January 2020 by Xiaochao (talk | contribs) (→Small Angle (12.5-degree) Pol 3He Asymmetry Production Runs (84 PAC hours) - to be fixed later)
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 or 4-8 calendar hours depending on beam efficiency)
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). - 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).
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 (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: - 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 two 60-min runs, make sure beam efficiency is high (goal: 200mC beam charge).
- N2 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 40-min runs, make sure beam efficiency is high (goal: 67mC beam charge). Make a note of ref cell gas pressure in Start-Run entry.
- H2 run: - 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 60-min runs, make sure beam efficiency is high (goal: 300mC 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: - Set HMS: 30 deg, -2.9 GeV/c (kine 3) - Set SHMS: 30 deg, -2.6 GeV/c (kine C-modifed) - 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 60-min runs at this setting, make sure beam efficiency is high. Make a note of ref cell gas pressure in Start-Run entry. - 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, make sure beam efficiency is high. - 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. 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). 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. 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. 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-modified)
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 (12.5-degree) Pol 3He Asymmetry Production Runs (84 PAC hours) - to be fixed later
Small Angle (12.5-degree) Reference Cell H2 and N2 Runs - need fixing
Small Angle (12.5-degree) 3He cross section - need fixing
Production Small angle (12.5 deg)
Overview - HMS at Kine 1, SHMS at 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 1 hour of 3He reference cell run. - We will take 40min 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: 67% of data at longitudinal (0 and 180 deg), 34% at transverse (90 and 270 deg) spin; - HMS: 12.5 deg, 5.7 GeV/c (electron) - SHMS: 12.5 deg, 7.5 GeV/c (electron) - Detectors: All SC bars ON
Procedure - Expected 3He gas rate: 880Hz (HMS), 185Hz (SHMS); triple if seeing glass windows - Expected pi/e ratio: less than 1/1 - Expected total electron counts (3He gas yield N+ plus N-): 101M? (HMS), 64M? (SHMS)
Summary of Kinematics (this may evolve with time)
HMS - Kine 1 (12.5 deg, -5.7 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 (12.5 deg, -7.5 GeV, resonance), 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 (12.5 deg, -5.7 GeV), SHMS at Kine D (12.5 deg, -7.5 GeV), 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
