Transverse electron guns for plasma excitation

Femtosecond Electron Guns for Ultrafast Electron Diffraction*

The photocathode radio-frequency (RF) gun is a powerful electron source to generate a high-brightness femtosecond electron beam with energies of 1~3 MeV. The RF gun based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe directly structural changes at the atomic scale with sub-100 fs temporal resolution. In this paper, we analyze the ...

Low Emittance Thermionic Electron Guns*

TE 01 Excitation of an Electron Cyclotron Resonance Plasma Source

The uniformity of plasma generation in electron cyclotron resonance (ECR) reactors for materials processing, and the subsequent uniformity of fluxes to the substrate, are generally a function of the mode of the microwave radiation injected into the chamber. In this paper, a finite difference time domain (FDTD) simulation is used to demonstrate the consequences of exciting an ECR reactor using a...

High Average Current Electron Guns for High-Power FELs

High average power FELs require high average current electron injectors capable of generating high quality, short duration electron bunches with a repetition rate equal to the frequency of the rf linac. In this paper we propose, analyze and simulate an rf-gated, gridded thermionic electron gun for use in high average power FELs. Thermionic cathodes can provide the necessary high current, have l...

Observation of a Charge Limit for Photocathode Electron Guns

The Photocathode Electron Gun (PEG) at SLAC is required to produce bunch intensities of up to 10 electrons within 2 ns (8 Amps). Operation of PEG has demonstrated a ‘Charge Limit’ phenomenon, whereby the charge that can be extracted from the gun with an intense laser beam saturates at significantly less than 10 electrons (the expected ‘Space Charge Limited’ charge) when the photocathode Quantum...