Talk:August 10, 2015 - CEBAF/LERF

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== LERF gun / photocathode ==


  • SF6 insulating gas: Bubba is working on re-plumbing a short section of the SF6 recovery system to achieve lower pressure when moving gas from the tank to the storage bag. This will help minimizing the amount of air currently introduced into the system during gas transfers.
  • Vacuum:RGA traces and UHV ion pump indicate vacuum in excellent conditions [1]
  • Kr gas processing system: Turbo pump and line connecting to Kr delivery system and to gun vacuum chamber is operational, ~ 2E-9 Torr. Video cameras and links to the control room are operational. Remote control Kr leak valve is operational.
  • Radiation monitors (to characterize field emission): Functional.
  • Other:Need new lightbulbs (fluorescent) for lighting fixtures in injector pit. Jim coleman is taking care of this.

Plans for starting HV checks/ops

  • 1. SF6 system. Complete re-plumbing. The HVPS and gun SF6 tanks will be pumped down and backfilled with dry nitrogen several times after re-plumbing job to remove as much moisture as possible before new SF6 is pumped into the tanks. New gas bottles will be delivered on Wednesday August 12., but this is the usual weekday for Power Permit. Most likely we will have the system ready with new SF6 on Thursday Aug 13.
  • 2. Kr. gas processing system: Bake the hose/line between the turbo pump and the valve to the gun.
  • 3. HV check: I will coordinate with J. Coleman to lock up the LERF into Beam Permit on Friday Aug 14 if step 1 is complete. We will learn more about the expected time to complete high voltage conditioning once we get a chance to check out the gun with voltage, and if Kr processing is necessary.
  • 4. Photocathode: After High voltage conditioning, heat clean and activate the photocathode. Map QE using the installed solid-state green laser beam. We need to check functionality of the QE scanner hardware and software.
  • 5. Training: Those interested are welcome to join in to learn about every step in the process.