Outline For Thesis

Abstract, Intro (obviously)

• Current experiments requiring the use of GaAs photo-guns - polarized electron beams
• What is a photo-gun?
• Description of the problem - ionization & why is it bad for electron beam production & electron guns?
  • Ion Back-Bombardment & QE degradation of the photocathode
    • How/where are ions formed in the photogun?
    • How many ions reach the photocathode and what are their energies?
    • How many of these ions contribute/correlate to QE damage?
  • Ion Mitigation Techniques
    • What experimental techniques are currently available? - Clearing electrodes (biased anode), other ion tracking codes (IBSimu, SIMION, etc.)
  • Theoretical/Computational techniques

• • CEBAF Injector - What is it? How do we (currently) model it?

• Literature review

Ionization Simulations with GPT Custom Element

Ionization Theory

• Can be pulled from PSTP proceedings and tech notes. Will include:
  • Ionization Cross Section & Production Rate
  • Secondary Electron Differential Cross Section (SEDCS)
  • Ion Energy Distribution (Maxwellian)
  • Momentum/Energy Conservation?

GPT Custom Element Algorithm

• Description of how the custom element works and is used to simulate ionization
• Benchmarking with theory and IBSimu (Can be pulled from future GPT/IBSimu paper)...maybe put in the LIfeSize Runs Section?

Biased Anode To Mitigate Ion Back-Bombardment

• Ion back-bombardment theory & how the biased anode will mitigate it (Can be pulled from PSTP)
• Summer 2019 Biased Anode Experiments
  • Experiments at CEBAF
  • QE Measurements & Charge Lifetime Analysis
  • QE Scan Analysis
  • GPT Simulations (w/custom element)
  • Results/Discussion
• Similar for Winter 2019-2020 Experiments?

Analyzing 2017 LifeSize Runs with GPT/IBSimu

• Description of Experiment
• Analysis of results with GPT custom element
• Comparison & benchmarking with IBSimu

Ion Trapping at the Gun Test Stand (GTS)

• Theory
• Ion Trapping Experiments - Ghost Beam and Steel Shield
• GPT Simulations (w/custom element)
• Results/Discussion

Discussion/Conclusions

Go to To-Do List

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