Thursday, Apr. 7: DAY Shift

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Shift Status Notice

MCC is hopeful that CW beam could be delivered by mid-shift. shift is on stand-by

  • TO must report to shift.
  • Remaining crew must stay in the area.
    • Notify RC of contact information.
    • Be ready to return to shift on short notice.

Shift Duties When No Beam

  • Monitor target (keep in HOME position)
  • Respond to calls and alert RC as needed.
  • Fill out shift checklist during this shift.
  • If beam is close to returning, notify the RC.

If Beam Returns

  • Perform Beam After Extended Downtime procedure from below
  • Proceed with Production data taking.

Beam After Extended Downtime

This procedure is to be

  • Harp Scans
    • Move target to HOME position (if not already there) (mask target motion!)
    • Turn VDC HV OFF for both arms.
    • Turn DVCS Calo HV OFF
    • Ask MCC for Raster OFF (check that it turns off in the scope)
    • Ask MCC to perform Harp Scans (on IHA1H04A and IHA1H04B)
      • Must have three peaks on each with a resolution of ~200-500 μm
      • Have seen a "shoulder" on the last peak before. May be acceptable if other 2 peaks are fine.
    • Ask MCC to make an ELOG with the results of the Harp Scans
  • Beam Centering on Carbon Hole Target
    • Move target to the Carbon Hole position (mask target motion!)
    • Ensure Left-HRS momentum is ~1 GeV/c
    • Set Left-HRS DAQ configuration to LeftHRSnew
      • Set prescales as ps_i = 1 for i = 1-6, and ps=0 for all others
    • Turn VDC HC OFF for both arms.
    • Turn DVCS Calo HV OFF
    • Ask MCC for Raster ON at 2x2
      • Check that it turns on in the scope, and check Raster GUI to confirm 2x2 setting
    • Ask MCC for 5 μA beam
      • Run spot_L as explained in the detailed instructions
      • If not centered ask MCC to move beam accordingly (check board for coordinates)
      • Repeat test with different beam position until target is centered.
  • Raster Target
    • Start the same settings as carbon hole centering
    • Move to Raster Target (mask target motion!)
    • Ask MCC for 5uA beam with Raster ON (2x2)
    • Check rates and confirm they are consistent with rates seen during HOME position
      • If the rates are low and consistent, then move on to next step
      • If the rates are high, it may indicate the beam has an angle that causes the beam to scrape on an edge of the target
        • Notify the RC
        • Ask MCC to readjust bpm positions until this angle is removed
        • When done, perform another Carbon Hole run just to be sure.

Production Running

For the remainder of the shift take 1 hour runs in the production configuration DVCS: Kin_48_2

Beam current 15 μA
Target LH2
Raster ON (2x2mm2)
VDC HV (both arms) ON
DVCS Calo Angle; 15.185°
DVCS Calo Distance 2.0 m
LHRS Polarity Negative
LHRS Momentum 3.996 GeV/c
LHRS Angle 20.243°
LHRS Q1 Current 1916.640 (regulator OFF)
prescaleL PS9=1 (all others zero)
RHRS Polarity Negative
RHRS Momentum 2.101 GeV/c
RHRS Angle 48.892°
RHRS DAQ Config RHRSadaq2
prescaleR PS1=PS2=PS3=1, && PS8=200 (all others zero)