Mar 6 2024

Updates

• Max, Gabriel
  • Repeated lens optimization for MFX2I01 and MFX1I03 to minimize beam size at MDR1I02 and MWF1I04...
    • R30 16°/30°, SW FX lenses
    • recess +0.1 mm, +0 mm, and -0.1 mm compared to nominal
    • produced lens settings at 0.001 pC and used them at 0.340 pC (similar to machine setup strategy)
    • Comparison of R30 16°/30° lens optimization results
    • qualitative shape of curves similar; doing the optimization the other way around would not change the numbers by too much
    • recess affects optimal lens setpoints (unsurprisingly) but causes no unmanageable differences in beam parameters
    • minor emittance increase due to space charge
  • Plan B
    • we decided to keep the Plan A Pierce angle but use the junction design from R30-3
    • mitigate risk of field enhancement at junction at the cost of higher surface field on lip
    • Gabriel's material from last time for reference: R30-4 junction angle and lip radius gradients vs junction angle
    • minor effect on beam: Comparison of R30 16°/30° and 16°/60° focal lengths
  • Test plan for R28 phase space measurement at CEBAF: https://tasklists.jlab.org/bslist/tasks/111123
    • extends Yan's measurement with option for Twiss-parameter fit
    • perfunctory attempt with R30-3 gun last summer gave excessive emittance, likely due to chromox viewer, but better than nothing?
• Alicia
  • 140 and 180 kV R28-2 operational settings scaled to 200 kV for R30-4