Conveners
3.1 Plasma, Ion, and Electron Sources II
- John Harris (Air Force Research Laboratory)
Photocathodes exhibiting simultaneous high quantum efficiency, low mean transverse energy, and fast temporal response are critical for next generation electron sources. Currently, caesiated negative electron affinity GaAs photocathodes have demonstrated good overall results. However, due to the nature of the photoemission process and the details of the Cs surface structure, a tradeoff exists....
Recently, we have shown that a waveguide integrated graphene photocathode excited with sub-workfunction energy photons can emit electrons at optical power densities significantly lower than traditional multi-photon or strong-field emission cathodes using metallic tips. Initial modeling efforts indicated that the behavior was due to non-equilibrium heating of electrons in graphene beyond the...
Laser-driven ultrafast electron emission offers the possibility of manipulation and control of coherent electron motion in ultrashort spatiotemporal scales. Superposition of a high DC field will enable the generation of high electron emission currents. The process would be facilitated by quantum tunneling across the potential barrier at the surface [1], aided by the absorption of energy...
This abstract reports on the status of the diamond field emitter array (DFEA) cathode project at Los Alamos National Laboratory (LANL). DFEA pyramids have nanometer scale tips and produce high currents with small emittance, making them a promising candidate for use in compact dielectric laser accelerators. At LANL, we recently established the capability to fabricate DFEA cathodes by using a...
We present the first experimental demonstration of production and transport of a shaped electron beam from a diamond field emitter array (DFEA) cathodes in an RF gun. DFEAs are arrays of diamond pyramids with exquisitely sharp tips and micron-scale bases that produce high current densities. These arrays can be fabricated in arbitrary shapes, ranging from single tips to many millions of tips,...
Carbon Nanotube Fibers (CNFs) have demonstrated excellent field emission (FE) properties and thus hold significant potential for use as electron sources for vacuum electronic devices (VEDs). CNFs were fabricated from pre-made carbon nanotubes (CNTs) mixed with chlorosulfonic acid resulting in a dopant with CNTs composing 2-6% of the solution mass. This dopant was extruded through a small...
Explode emission cathodes can be used to generate intense-current relativistic electron beams(IREBs) required for high-power microwave(HPM) systems, its characteristics affect the performance of HPM system. This type of cathode forms a plasma on the surface of the cathode during the emission process, and the electron beam is mainly obtained from the plasma. Therefore, the characteristics of...
