Abstract: Beam monitors, methods of use and fabrication are provided herein. Beam monitors can include a rounded beam cavity with one or more waveguide connected thereto, from which a signal can be used to determine one or more beam characteristics. Such monitors can include a beam intensity monitor that includes a cylindrical beam cavity with a rectangular waveguide extending from a periphery, from which beam intensity can be determined. An advanced beam monitor can include a multi-moded beam cavity having multiple waveguides connected at distinct locations, each corresponding to a differing excitation mode. Such monitor can include an elliptical beam cavity and five waveguides connected thereto, signals from which can be used to determine beam charge, beam position and beam size in both the x-direction and y-directions. Beam monitors can be stand-alone devices or integrated within linear accelerators. Accelerators can include off-axis beam monitor coupling ports and on-axis tuning features.

Abstract: An apparatus for generating high frequency electromagnetic radiation includes a whispering gallery mode resonator, coupled to an output waveguide through a coupling aperture. The resonator has a guiding surface, and supports a whispering gallery electromagnetic eigenmode. An electron source is configured to generate a velocity vector-modulated electron beam, where each electron in the velocity vector-modulated electron beam travels substantially perpendicular to the guiding surface, while interacting with the whispering gallery electromagnetic eigenmode in the whispering gallery mode resonator, generating high frequency electromagnetic radiation in the output waveguide.

Abstract: An apparatus for generating high frequency electromagnetic radiation includes a whispering gallery mode resonator, coupled to an output waveguide through a coupling aperture. The resonator has a guiding surface, and supports a whispering gallery electromagnetic eigenmode. An electron source is configured to generate a velocity vector-modulated electron beam, where each electron in the velocity vector-modulated electron beam travels substantially perpendicular to the guiding surface, while interacting with the whispering gallery electromagnetic eigenmode in the whispering gallery mode resonator, generating high frequency electromagnetic radiation in the output waveguide.

Abstract: An apparatus for generating high frequency electromagnetic radiation includes a whispering gallery mode resonator, coupled to an output waveguide through a coupling aperture. The resonator has a guiding surface, and supports a whispering gallery electromagnetic eigenmode. An electron source is configured to generate a velocity vector-modulated electron beam, where each electron in the velocity vector-modulated electron beam travels substantially perpendicular to the guiding surface, while interacting with the whispering gallery electromagnetic eigenmode in the whispering gallery mode resonator, generating high frequency electromagnetic radiation in the output waveguide.