From PREX Wiki
Revision as of 10:28, 19 June 2019 by Sanghwa (Talk | contribs) (Low Current Commissioning)

Jump to: navigation, search


PREX Run Plan for   Commissioning   and   Auxiliary Measurements

See also the Daily Run Plan and Earlier Daily Run Plan

PREX I - 2010 Run Plan

The experiment is approved for 35 PAC days including 25 production days. There are 49 days on our calendar.

Below is a list of tasks in the approximate time order, with person(s) responsible, approximate amount of time required, and comments about the conditions or needs. The time will, in most cases, be broken up into manageable chunks. For example, the GEM commissioning will occur in about 4 periods of time, each 4 hours, separated by at least one day. After commissioning we go into a regular production mode; we will provide an updated document webpage for shift worker instructions.

Total time: ?   Based on this list, each day we will come up with an adjustment to the Daily Run Plan. Some flexibility will be needed to accomodate problems and changes in plans.

Beam Restoration

  1. Basic beam setup 1 shift: Yves Roblin
    • establish tune beam and low current CW beam in the hall.
    1. Establish beam to dump, through Compton chicane
    2. Design match to hall expected as part of original configuration, if additional beam time is required will be necessary to coordinate with optics/production runplan
    3. ion chamber calibration will be skipped until we can get targets in (MASK ION CHAMBERS); CG will coordinate
  2. Source and Parity Quality Beam 0 shift (complete before 6/17): Caryn Palatchi, Amali Premathilake, Kent Paschke
    1. Source laser optics configuration and initial setpoints done
    2. Wein left/ Wein Right injector optics configuration done
    3. Characterize injector optics configuration done

Low Current Commissioning

  • Basic beamline commissioning (may be 3 shifts total)
    • Need Yves prediction of raster size from optics design to adjust test
    • Would like to locate collimator before ion chamber calibrations. Should be expert driven, so maybe ordering depends on how step 1 takes.
    • Establish low-current beam with spectrometer magnets on. Establish centering on collimator. BPM offset calibration. Commission target ladders.
    • Preparations:
      • Stripchart on ion chambers, with bpm4e and bpm4a positions
      • stripchart on collimator and beamline temps with bpm 4a and 4e positions
      • stripchart on compton rates (with beam current) no more 2x what is present in HACOMPTONLOG
  1. Verify Beamline setup 1 shift Yves Roblin, Bob
    • Tune mode. No target. Raster off. Ion chambers masked. ATLis 19326
    1. beam transport through Compton chicane up to 5uA CW.
      • Rates in finger scintillators no more 2x what is present in HACOMPTONLOG
      • ComptonUS1 ~ 30 Hz, ComptonDSbg1 ~ 870 Hz, ComptonDCbg2 ~ 1010 Hz
    2. spot size at target (harps) (nominal spec is 150 um x 150 um. Larger is better)
      • Use 5uA CW, but keep eye on compton rate, ion chambers, temps.)
    3. Tune beam. Turn on septum and verify still on dump. Clean transport to dump for PREX set points
    4. 1 arm running (Q1 on) test to verify no beam motion.
    5. Turn on both Q1 spectrometers.
  2. Hall bullseye scan 0.5 shift Bob
    • harp scans at each of 5 points around nominal center, (0,0), (2,2), (2,-2), (-2,-2), (-2,2).
    1. Tune beam, find each point. Watch ion chamber and temperature stripcharts.
    2. If no sign of interception, use 2-5uA CW for harp scans for each position and get BPM calibrations.
      1. Watch ion chamber and temperature stripcharts.
      2. If PREX expert is available, parasitically collect data for low current beam monitoring (cavities). If during day have RC inform J Musson before taking this data.
    3. position at (0,0). Set nominal raster to 8x8. Establish 2uA CW. Watch ion chamber and temperature stripcharts. This should verify passage through collimator. If IC or temp jump, terminate beam, try with 6x6 or 4x4 raster. If cannot pass, go to collimator position scan.
  3. Warm target position 0.25 shift Kent (Silviu, present or on call?)
    • Verify target alignment.
    1. insert warm ladder, carbon hole.
    2. Set raster nominal 8x8 (or what could be used.)
    3. establish 2uA CW. Run spot++ to find carbon hole. log it.
    4. Adjust raster setting to establish 4x4 raster size. Log it.
    5. if carbon hole not in 4x4 raster view, need to reconsider. (move beam, or use off center?)
  4. MCC ion chamber calibration - Thin target 0.25 shift Kent
    • will enable us to run higher current. Procedure discussed with Eric Forman: thin target: ramp 2-10uA on thin C (0.5mm).
  5. Cold target position 0.25 shift Kent (Silviu, present or on call?)
    • Verify target alignment.
    1. insert warm ladder, carbon hole.
    2. Set raster nominal 8x8 (or what could be used.)
    3. establish 2uA CW. Run spot++ to find carbon hole. Log it.
    4. Set raster to 4x4 set point from before. Use spot++ to verify it.
    5. if carbon hole not in 4x4 raster view, need to reconsider. (move beam, or use off center?)
    6. Move to natural lead target
    7. establish 2uA CW. Run spot++ to verify raster size, not hitting edges. Log it.
    8. set raster to large nominal setting (8x8, or what can be used). re-establish 2uA CW. Use spot++ to look for edges of target.
    9. return raster to 4x4 set point. verify with spot++.
  6. MCC ion chamber calibration - thick Target 0.25 shift Ciprian G
    • Procedure discussed with Eric Forman: thick target calibration procedure (ramp 2-10uA) for ALL ion chambers (including the dump)
    • Must keep rates in compton finger scintillators; no more 2x what is present in HACOMPTONLOG
    • parasitic: first check of SAMs at low current (call Devi? or Dustin? before starting)
  7. Collimator checkout 0.5 shift Yves, Ciprian G, Kent P
    • will verify that we are cleanly going through the collimator and cross check power deposition calculations
    1. setup ion chamber strip chart
    2. Establish 2-5uA tune mode, with empty target. Use 4x4 raster.
    3. move beam in 2mm steps as much as +/- 1 cm in both horizontal and vertical. Watch for rise the ion chamber signal. Record positions where edges of the collimator bore are found.
    4. set beam to center on colllimator based on those edges.
    5. compare to position of carbon hole on warm and cold ladders. Do we need to recheck target frames for targets? Do we need to change encoder positions?
  8. Very low current commissioning 0.25 shift Yves. Ye Tian. Caryn.
    • commission low current cavities relative to stripline calibration. Commission cavity bpm lock.
    • Note: position scan and lock setup are separate pieces, can happen at different times.
    • Either/ both can happen later (during optics running). Needed before sieve-out Q2 studies.
    1. Cavity lock
      • [Yves is required for step]
      1. setup cavity stripchart. Establish 2uA CW.
      2. setup cavity slow lock. Verify that in operation this lock holds the position in the cavity epics readback.
      3. lower current to 100 nA. Verify that the lock still holds the cavity epics readback.
    2. Cavity Position scan.
      1. setup cavity stripchart. Establish 2uA CW.
      2. Find corrector positions for +/-2mm in X, Y.
      3. Reduce current to 50nA.
      4. set to each corrector position, verify position measurements with epics readback

Spectrometer Commissioning

Detailed Optics Plan Name and time assignments needs to be worked out by optics crew

  1. tracking checkout - Tune B configuration 1 shift: Bob M, Ryan R, Chandan G
    1. Sieve IN: initial checkout
      1. put in C/Ta target; check rates with scalars
      2. VDC + GEM checkout; look at tracks, VDC spectra; (GEM):noise, pulse-heights, tracks
      3. Sieve reconstruction verification
  2. Tune septum and HRS magnets - Sieve IN 1 shift Nilanga L, Chandan G, Ryan R:
    1. tune septum for the central ray (quad scans)
    2. inner edge verification
    3. Q1 acceptance scan
  3. Small spot at quartz Sieve IN, thin Carbon, 0.25 shift Ryan, Dustin, Seamus or Nilanga
    1. modify tune to get small spot at quartz (with raster on)
  4. Optics calibration data - Sieve IN 0.5 shift Chandan G, Ryan R, Ye:
    1. spectrometer momentum scan
  5. Water cell pointing 1 shift Chandan G, Ryan R, Ye:
    1. Sieve IN: pointing measurement
    2. Sieve OUT: pointing measurement
  6. Quartz detector checkout 1 shift: Dustin M,
    1. verify small spot at quartz (thin C, low current, no raster, sieve out)
    2. thin C, low current, no raster, Sieve OUT: positions Plan
    3. PMT spectra
    4. rates
    5. stub check?!
  7. Q2 measurement 0.5 shift:
    1. Production target

High current checkout

  1. Basic setup 0.5 shift Yves R, Ciprian G:
    • No target.
    • 50uA beam current, through Compton (backgrounds on fingers and Compton photon detector).
  2. High current with target 0.5 shift Ciprian G, Dustin M:
    1. Establish 4x4 raster. Insert lead target.
    2. Detector and SAM voltages (Dustin M)
  3. Beamline instrumentation calibration 0.5 shift Caryn P,
    1. Current ramp for BPM/BCM calibrations and detector pedestals
  4. Initial production condition test 0.25 shift Caryn P,
    1. detector and SAM widths
    2. regression sensitivities
    3. beam noise and asymmetry check
    4. collimator water and thermocouple temperatures,
    5. radiation monitors and ion chamber stability
  5. Width studies 0.5 shift KK,
    1. detector and SAM widths, targets, shutters, etc
    2. deinstall shutters at conclusion of test

Establish Production Conditions

  1. Beam modulation 0.5 shiftVictoria O., Ye T,:
    1. turn on and set amplitudes (plan needed)
    2. test orthogonality
  2. Detector checkout 1 shift Dustin M:
    1. quartz detector stub test (plan needed)
    2. width study (plan needed)
    3. raster sync (plan needed)
  3. Spin Dance 1 shift: Simona Malace, Sanghwa Park
    1. Moller polarimeter commissioning (establish beam) (plan needed)
    2. Short spin dance (run plan needed, established optimal spin angle for this Wien state) (plan needed)
  4. Hall PQB 1 shift Caryn P,:
    1. Check asymmetries in the hall
    2. Adiabatic dampening / Matching (plan needed)
      1. Use helicity magnets to tune phase trombone
    3. Establish feedback (if Hall C is not on schedule their feedback for later)
  5. Production: 0.5-3 shift? All
  6. AT measurement: 1.5 shift? All (plan needed)
    1. Do we need to verify zero longitudinal using Moller polarimeter?
    2. Carbon
    3. Lead
    4. Calcium
  7. Initial Moller commissioning 1 shift Simona M, Sanghwa P,
    1. minimal set for first absolute measurements
  8. Initial Compton commissioning 1 shift Dave G, Juan Carlos C,
    1. minimal set for measurement conditions

Start Production

Important Activities After First Few Days

  1. Linearity Studies --
  2. Background Studies --
    1. Scans of Septum Magnet and HRS Dipole
    2. Thin Lead Target to check for inelastics at high-resolution
    3. Thin C12 to measure diamond background
  3. Possible scan of Q1 to optimize acceptance and verify that collimator defines acceptance. (old idea, still relevant?)
  4. We will start with the Wein in Spin-Right. Once we switch to Spin-Left we need to do another spin-dance.

Polarimetry Studies

  1. Compton Commissioning --   Gaskell,
    1. Beam Tune, Background reduction -- Bteam,
    2. Compton Cavity Checkout --
    3. Photon Detector Checkout -- CMU group
  2. Moller Commissioning -- Simona Malace, Don Jones,
    1. Magnet Alignment -- 1 shift (swing)
    2. Raster size and pulse-mode -- 1 shift (day)
    3. Target commissioning - 3 shifts
    4. Pulse-mode target commissioning - 2 shifts
    5. DAQ checkout -- 1 shift

Important Activities During run

  1. Linearity Studies --
  2. Background Studies --
  3. Repeat Q2 and pointing measurements
  4. Arc Energy Measurement