GTS meeting 9 13 16

• Prep Chamber
  • Waiting for the modified puck holding mechanism to be made available and we will do the feasibility test first. See concept here: Media:SPRINGINSTALLED.pdf
  • At this stage we mount the existing top heater assembly and mount a 10" bottom flange with only one center port for attaching the bottom heater.
  • Upon verification of the usability of the puck fixture mechanism, we will go for increasing the top heater length and the mask rod length
  • If decided then we will add a separate K effusion source, we have room to fit. Only need additional hot air assembly for heating. We will need a heater control unit for it.
  • The Sb pellets will be added before we close the top lead.
  • The chamber inside and all view ports were solvent cleaned and the view ports are already installed on the chamber and on top and bottom flanges.
  • The two long NEG cartridges have been replaced with four small NEG cartridges. All NEGS are now above the manipulator port plane.
  • Bottom flange is replaced with the silco coated 5 port flange. Fasteners will be tightened after testing with puck fixture on top heater stalk is completed.
  • The long manipulator is replaced and mounted on the chamber with a good one.
  • The RGA is cleaned, tested and mounted on the chamber
  • A valve is added in between the ion pump and the GTS chamber to isolate the chamber from ion pump if increased background pressure is required during photocathode fabrication.
  • The leaky gate valve between the gun and the prep chamber has been replaced with a good one.
• Gun HV chamber
  • While we want to minimize amount of NEG particulates, we also need significant Hydrogen pumping speed during high voltage conditioning.
  • We will then install 6 WP modules, not 8 like the UITF gun, and will use a perforated plate rather than the wire mesh used in the UITF gun. The perforated plate will reduce pumping speed, but should also reduced the field reaching the WPs compared to the wire mesh.
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  • Yan has done some POISSON modeling that shows field is reduced by at least a factor of two with the wire mesh. Media:Electric field with NEGs in Gun Chamber.pptx
  • We will do a pre-bake and NEG WP's full activation without the electron win TL1137, since SAES reports that particulate productions is considerable reduced after the first two activations, see: [1]
• Magnet Installation and test
  • Update from Riad
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• Pictures of multi-alkali photocathode removed from the prep chamber after being used to deliver 1 mA, 300keV beam.
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