Feb 7 2024
From last time
- Carlos will incorporate into the time line a potential vent and electrode swap in case of failure to HV-condition or get the beam out (by no means anticipated, but good to know how long it would take)
- Max, Gabriel, and Alicia will complete simulations of:
- shallow junction angle
- tolerance bands around nominal values, especially cathode recess, to evaluate injector acceptance (see parameter table from last meeting).
- Final checks: tilted anode, biased anode, 140 kV
- Deadline to define Pierce angle: Today. Max, Alicia.
- Deadline to provide Keith Harding with the chosen models (TWO Pierce angle options): Friday, February 9, 2024. Max, Gabriel.
- February 13, 2024. Present before the B-Team meeting the strategy followed for arriving at the optimized Pierce angle. Max and Alicia.
- Geometrical parameters downselect
Table of parameters
| Parameter | Unit | Nominal value | Fabrication uncertainty | Simulation band | Comments |
|---|---|---|---|---|---|
| Hole inner radius | mm | 6.4135 | +/- 0.3? | +/- 0.3 | to edge of actual metal, as measured with caliper |
| Pierce angle | ° | 16 | ? | +/- 2 | |
| Cone/sphere junction angle | ° | 30 | ? | 30 -- 62 | was 62°; smooth transition = 26.971° |
| Cathode recess | mm | 0.188 | 0.05 | 0.1 | from Keith's drawing; error may be larger for old pucks |
| Cathode tilt | ° | 0 | +/- 0.5 | 1 | |
| Laser spot size (RMS) | mm | 0.5 | 0.1 | 0.2 |
- Add CST/GPT comparison between +/- values here
Updates
- Max, Gabriel, Alicia: The nominal values above give good agreement with the R28 model; the smooth transition at the junction gives minimum field enhancement at the lip and has been shown not to cause problems due to the protruding edge (Sajini's design).
- Alicia: What phase-space parameters are desirable? (simulations done with R30-4 candidate phase spaces)