CEBAF upgrade meeting - December 13, 2017

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Install the new 200kV gun during 2018 SAD, sometime after the Bubble Chamber experiment. Imagine ~ May 2018


Gun and BPM NEG tube status:

  • After two days of krypton processing, the 200kV gun at UITF seems to be free of field emission at 200kV bias voltage. Need to start making beam to evaluate lifetime, photogun performance
  • Phil waiting for power supply repair, to finish NEG coating of two modified M20 BPMs and the solenoid nipple
  • Phil to get the bad modified M20 BPM repaired
  • Poelker to order clean krypton tank and regulator for dedicated gas processing system at CEBAF
  • Need to visit the tunnel to check the gun pump configuration, prepare for unusual plumbing to reach bake pump
  • Need to order the right HV cable for CEBAF, R350 to R28. Should not be as long as one in UITF
  • Matt/Danny to submit job to machine shop: spare 200kV shed electrode, tee with mushroom top, Bubba to polish it

200kV gun images.jpg


Baked beamline with two-Wien spin flipper


  • media: baked beamline layout 12 December 2017.pdf
  • Danny to add another bellows near the spin flip solenoids
  • Danny to provide Z-locations of magnets and apertures
  • Joe to model the beamline with Elegant, check the optics when each Wien is set to 90 degrees, and when both Wiens are set to 90 degrees, while ensuring waist inside Wien#2
  • Joe to consider alternative layouts, with quads for improved optics when Wiens are at 90 degrees, and with shorter A1/A2 length, or apertures eliminated
  • Alicia to model Plan A layout using GPT, evaluate transmission for a variety of spin flipper settings
  • John to build +/-20kV Wien HV supplies, setup in UITF to drive the UITF Wien filter at "extreme" settings for long duration
  • Phil to install Wien magnet pair, choose the pair without shorts. Work with Kevin Banks to drive these coils at extreme settings for long duration
  • Setup meeting with Jeff Dale, Jay Benesch, Joe Meyers and Danny to manufacture better Wien magnets

Beamline 12 12 2017.jpg