Thesis outline

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Introduction

  • Magnetized electron beam
  • Applications of the magnetized electron beam
    • Magnetized electron cooling
  • Jefferson Lab magnetized electron source for the JLEIC cooler


Generation of the magnetized electron beam

  • Experimental setup (DC HV gun, photocathode, cathode solenoid, RF laser, focusing solenoids, etc.)
  • Beam diagnostics


Beam dynamics

  • Beam matrix
  • Phase space
  • Emittance (thermal, phase space, geometric)
  • Effective(drift) emittance (emittance of the magnetized beam)
  • Measuring the beam emittance


Space charge effect

  • Space charge effect in the magnetized beam

Simulations on the magnetized electron beam

ASTRA

    • Initial particle distribution
    • Field maps (3D E field map, 2D B field map)
    • Space charge calculation mechanism
    • Emittance

GPT

    • Initial particle distribution (Laser*QE image processing)
    • Field maps (3D E field map, 2D B field map)
    • Space charge calculation mechanism
    • Emittance

Post-processing (MATLAB)

Characterization of the magnetized beam

Experimental method

    • Beam size vs solenoid I
    • Rotation angle vs solenoid I
    • Emittance vs solenoid I - two different laser sizes
    • Emittance vs laser spot sizes - max solenoid current

ASTRA/GPT simulations (Simulation of all the above variations)

  • Conclusions (comparisons -measurements vs simulations, mismatch oscillations, negative rotation angles, etc.)


Experiments and numerical simulations of the space charge dominated magnetized beam

Experimental method

    • Pulse energy vs extracted charge-for different magnetizations
    • Space charge current limitation dependence on gun high voltage-for different magnetizations
    • Space charge current limitation dependence on pulse width-for different magnetizations
    • Space charge current limitation dependence on laser spot size-for different magnetizations

GPT simulations

  • Conclusions (Comparison-measurements and simulations)


Redesigning and performance of the photogun

  • Existing electrostatic design
  • Modified electrostatic design
  • Polishing and gun assembly
  • High voltage conditioning


Repeated experimental and numerical simulations results of the space charge dominated magnetized beam with the new photogun

Summary and Conclusions

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