Thesis outline

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

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

Summary and Conclusions

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