Feb 14 2024

From last time

• Plan A is the 16°/30° design. We are going to start the design/fabrication process to quickly get a practice part and go through all the steps.
• Alicia's GPT simulations of the injector with Max's distributions indicate all models from 15 to 18 degrees should be manageable. Higher Pierce angles (shorter focal lengths) give a large beam size in the first lens and give high transmission loss at apertures, but the latter is because everything has so far been simulated with the same lens strengths. Max and Alicia will continue this work to re-match the optics for each case to see if the whole system of gun + 1 or 2 lenses actually differs. These studies may identify a suitable Plan B geometry and tell us how much deviation from the nominal geometry can be tolerated.
• Meeting with Keith on Friday to get the ME design started.
• Presentation at the upcoming B-Team meeting (2/13/24) about the strategy followed to solve the R30-3 focusing problem. Carlos will make some brief introductory remarks; Max and Alicia will decide to divide the rest of the work as it makes sense.Presentation can be found here

Discussion

• ME design
  • Keith Harding attended the meeting. He talked to Vince and both developed a plan to control the hole size as best as possible per design.
    1. Keith will send Vince a draft drawing with hole diameter 0.010" smaller than per design, with a 0.002" radius.
    2. The shop will make two samples
    3. One sample will get mechanically polished per our procedure using the tumbler and diamond paste
    4. The hole diameter will be measured in the un-polished, and polished sample and compared. This will tell us how much the hole diameter increases after polishing
    5. Produce final drawing
    6. Fabricate final design part + 1 spare
  • Modeling and simulations
    • Max and Carlos received the following message from Matt: "...check that your 16 degree electrode properly matches into the first solenoid set to a realistic value that puts a beam waist at the 15 degree dipole. Good news, we know what this solenoid setting is, we use it today".
      

Path forward, conclusions

• Wrapping up simulations and forecasting simulations after measuring final piece hole size and puck recess
  • Alicia to optimize injector settings at 200 kV for R30-4 solution, using counter wound FX solenoids (the version which is still not fixed in regards to the middle plate).
  • Model injector at 180 kV for R30-4 using actual machine setting from the R28-2 run in the machine
• Updates from Carlos:
  • Preparing for practicing polishing on available stainless pieces similar in size to the cathode Pierce front end
    
  • Measuring holes size of test piece before and after polishing
  • Develop plan for puck test on manufactured piece for measuring wafer plane gap
• Technical Note
  • Gabriel to start drafting a procedure for developing electric fields maps in CST starting from ME models and implementing them in GPT
  • Max to coordinate the procedure writing with Gabriel and with Alicia to capture steps for model validation with beam-based measurements, and with full injector GPT model

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