Establishing beam in the Hall

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Configuration

  1. Magnets: BB magnet is ON. See the procedure to ramp up the BB magnet. SBS and corrector magnets are OFF to start. These magnets will be ramped up after initial beam steering, see steps below.
  2. BigBite Preshower, Shower (collectively BB CAL), GRINCH and Hodoscope HV is ON
  3. GEM HV remains OFF until we have good knowledge of the beam position
  4. DAQ: CODA configuration GMN1. Prescales ps1=0 (BB CAL trigger), all other triggers are turned off (set to psX=-1).

Procedure

  1. Check GEM HV is OFF and BB HV is ON (includes Preshower, Shower, GRINCH and Hodoscopes) [1]
  2. Ensure the target is at home, OUT of the beam path. SBS magnets should be off.
  3. First MCC centers the beam on the differential pumping (DP) apertures (0.75") and then delivers to the beam dump using the dump viewer.
  4. Verify the intrinsic beam spot size on target. (follow link for instructions)
  5. Ion chamber calibration on empty target position. This calibrates the dump ion chambers.
  6. Check beam position and raster size using carbon hole. (follow link for instructions)
  7. Ask MCC to do ion chamber calibration on all Optics targets that are being used in the optics program. This calibrates the ion chamber at the target for our optics program. The other targets (LH2, LD2, dummy) will have to be calibrated as we need to use them.
  8. Call MCC to tell them we want to ramp up the SBS magnet and correctors. MCC has a procedure to do this, stepping through the SBS magnet strength in steps of 25% from 0 to 100%; this ensures beam will stay centered on the dump.
  9. Once the SBS and corrector magnets are at their full nominal settings, take another raster scan (step 6) to verify the spot size on the carbon hole 2-mm target. Work with MCC/Ops to re-center the beam if necessary.