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Revision as of 12:49, 9 June 2019 by Kent Paschke (Talk | contribs) (High current checkout)

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This is a Draft being updated from previous run plans. Please ignore until further notice

This was for the 2010 PREX-I run.   A run plan for PREX-II and C-REX is forthcoming.

PREX Run Plan for   Commissioning   and   Auxiliary Measurements

See also the Daily Run Plan and Earlier Daily 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.

Beam Restoration

  1. Basic beam setup: Yves Roblin,
    • beam transport to dump
    • beam transport through Compton chicane
    • Establish beam to dump, through compton chicane, spot size at target.
    • 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
    • initial ion chamber calibration for beam interception (on ladder); tune beam->CG
  2. Source and Parity Quality Beam: Caryn Palatchi, Amali Premathilake, Kent Paschke
    • Source laser optics configurations in progress
    • Wein studies done
    • Wein left/ Wein Right injector optics configuration
    • Source laser optics configuration and initial setpoints

Low current checkout

  1. Basic beam setup:
    1. MCC
      1. beam transport through Compton chicane @5uA (Yves Roblin, rates in finger scintillators)
      2. spot size at target (harps)
      3. turn on septum and very still on dump (viewer available?!); clean transport to dump
    2. Hall
      1. harp scans for BPM calibrations and raster check
      2. Bullseye scan
      3. low current beam monitoring (cavities) --> maybe this will be xchecked with HRS rates
  2. Warm target position::
    1. use spot++ to find carbon hole
    2. Put in Ta or this-C target. Scan few mm up-down, left-right, verify from rates we're not hitting a frame.
      • first check of SAMs at low current
  3. Cold target position::
    1. use spot++ to find carbon hole
  4. Collimator checkout:
    1. check rates with SAMs
    2. moderate CW and thick C/Ta target so we can check temps (need a simulation for collimator power for C/Ta target)
  5. Septum + Q1 checkout:
    1. clean transport to dump for PREX set points
    2. 1 arm running (Q1 on) test to see beam motion (Yves and Ciprian)

Spectrometer Commissioning

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

High current checkout

  1. Basic setup:
    • No target: high current setup through Compton (backgrounds on fingers and Compton MD) -- try to go to 70uA (or max, no less than 40uA)
  2. High current with target:
    • Pb target, raster on: Ion chamber calibration (near target): Ciprian more details needed
    • Detector and SAM voltages
  3. Beamline instrumentation calibration
    • Current ramp for BPM/BCM calibrations and detector pedestals
  4. Initial production condition test
    • detector and SAM widths
    • regression sensitivities
    • beam noise and asymmetry check
    • collimator water and thermocouple temperatures,
    • radiation monitors and ion chamber stability

Establish Production Conditions

  1. Spin Dance: Simona Malace, Sanghwa Park
    • Moller polarimeter commissioning (establish beam) (plan needed)
    • Short spin dance (run plan needed, established optimal spin angle for this Wien state) (plan needed)
  2. Hall PQB:
    • Check asymmetries in the hall
    • Adiabatic dampening / Matching (plan needed)
      • Use helicity magnets to tune phase trombone
    • Establish feedback
  3. Beam modulation:
    • turn on and set amplitudes (plan needed)
    • test orthogonality
  4. Detector checkout:
    • quartz detector stub test (plan needed)
    • width study (plan needed)
    • raster sync (plan needed)
  5. Production: (between 4 hours and 24 hours?)
  6. AT measurement: # AT measurement (plan needed)
    • Carbon
    • Lead
    • Calcium

Lead Target Checkout (1-2 calendar days)

  • High Current Commissioning -- 1 shift
    • Production target checkout (Priority activity) --   Bob Michaels et al
      • 100 uA on thick Lead, monitor radiation levels, establish luminosity limits
    • Electronics commissioning --   KK, et al
      • Establish LUMI performance characteristics
      • Detailed measurements of various oversampling configurations
  • Parity Commissioning -- 1 shift
    • Parity Quality (Priority activity) --   Kent, et al
      • IA feedback, beam modulation ( low current modulation - dithering commissioning before CW )
      • Evaluate SAM regression performance
    • Beam monitor calibrations --  
      • Bulls-eye scan, fixed gain BPM calibration, BCM calibration
  • Q2 Measurement -- 1 shift
    • Establish Q2 measurement sequence (Priority activity) --   Dustin, Nilanga et al
      • Drift chamber rate measurement at a few nA
      • parasitic GEM commissioning
      • try to establish a rate in GEMs, especially in quartz shadow, at 10-100 nA
    • ARC energy measurement --  
  • High Luminosity Detector Commissioning -- 1 shift
    • Characterization of Integrating Detector response (Priority activity) --   KK, Dustin et al
      • Estimate detector rates & impact of A_T hole flux
      • Evaluate primary detector and LUMI noise peformance
      • Evaluate BPM performance; compare strip-line regression to cavity regression
      • Establish empirical figure of merit for A_T hole detector
    • Final parasitic GEM commissioning --   Nilanga et al
      • Compare predicted and measured integrating width prediction at moderate current on thick target

Polarimetry Beam Checkout (1 shift)

  • Moller Beam Checkout -- 2 shifts
    • Moller magnet alignment (Priority activity) --   Moller team
      • Verify Moller magnet does not steer beam
    • Parasitic Compton Checkout --   Compton team
      • Feedback to MCC on beam quality
      • Simultaneous performance on Moller tune, compton background and sufficient raster

Polarimetry Checkout (4-5 calendar days)

  • Compton Commissioning -- 8 shifts   Gaskell,
    • Beam Tune, Background reduction -- Bteam,
    • Compton Cavity Checkout --
    • Photon Detector Checkout -- CMU group
  • Moller Commissioning -- 8 shifts   Simona Malace, Don Jones,
    • Magnet Alignment -- 1 shift (swing)
    • Raster size and pulse-mode -- 1 shift (day)
    • Target commissioning - 3 shifts
    • Pulse-mode target commissioning - 2 shifts
    • DAQ checkout -- 1 shift

Establishing Production (2-3 calendar days)

  • Production Checkout -- 2 shifts
    • Final detector alignment checks
    • Final LUMI/noise/helicity flip rate checks
    • Final beam modulation tweaks
    • Quick check for gross non-linearities
    • 4 hours longitudinal polarization production data
  • Transverse Polarization -- 4 shifts
    • Double-Wien Spin Manipulator Commissioning --   Joe Grames
    • Spin dance
    • 4 hours transverse vertical polarization production
    • 2 shifts transverse horizontal polarization production

Total time: approx 15 days !   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.

Important Activities after few days of production

  • Linearity Studies -- 1 shift   Kent Paschke
  • Background Studies -- 2 shifts
    • Scans of Septum Magnet and HRS Dipole
    • Thin Lead Target to check for inelastics at high-resolution
    • Thin C12 to measure diamond background
  • Possible scan of Q1 to optimize acceptance and verify that collimator defines acceptance.