An annular cathode for a vacuum tube includes a central cylindrical support whose axis is that of the cathode; an outer peripheral electron emitter with annular section whose axis is that of the cathode, extending over the outer perimeter of the cathode; and a folded skirt, secured at an inner end to the central support, and secured, at its outer end, to a plurality of lugs; each lug being disposed in series with the folded skirt, and secured with the folded skirt and with the inner surface of the electron emitter.

A method for generating multi-stream electron beams is disclosed, the method including connecting an inner cathode to a cathode stalk, connecting an outer cathode to the cathode stalk, driving the cathode stalk with a pulsed power generator at a single potential, producing a first electron beam from the inner cathode, and producing a second electron beam from the outer cathode. Implementations of the method for generating multi-stream electron beams may include where each of the inner cathode and the outer cathode may include nested magnetically insulated coaxial diodes (MICDs). The first electron beam and the second electron beam can be generated with different energies. A multi-stream traveling wave tube (TWT) and an electron beam generating apparatus are also described.

A method for generating multi-stream electron beams is disclosed, the method including connecting an inner cathode to a cathode stalk, connecting an outer cathode to the cathode stalk, driving the cathode stalk with a pulsed power generator at a single potential, producing a first electron beam from the inner cathode, and producing a second electron beam from the outer cathode. Implementations of the method for generating multi-stream electron beams may include where each of the inner cathode and the outer cathode may include nested magnetically insulated coaxial diodes (MICDs). The first electron beam and the second electron beam can be generated with different energies. A multi-stream traveling wave tube (TWT) and an electron beam generating apparatus are also described.

A self-assembling element fabricated using integrated circuit techniques may provide a small diameter helical conductor surrounding an electron beam for the construction of a vacuum electronic device such as a traveling-wave tube for terahertz scale signal.

An annular cathode for a vacuum tube includes a central cylindrical support whose axis is that of the cathode; an outer peripheral electron emitter with annular section whose axis is that of the cathode, extending over the outer perimeter of the cathode; and a folded skirt, secured at an inner end to the central support, and secured, at its outer end, to a plurality of lugs; each lug being disposed in series with the folded skirt, and secured with the folded skirt and with the inner surface of the electron emitter.

A tunneling electro source, an array thereof and methods for making the same are provided. The tunneling electron source is a surface tunneling micro electron source having a planar multi-region structure. The tunneling electron source includes an insulating substrate, and two conductive regions and one insulating region arranged on a surface of the insulating substrate. The insulating region is arranged between the two conductive regions and abuts on the two conductive regions. Minimum spacing between the two conductive regions, which equals to a minimum width of the insulating region, is less than 100 nm.

The present invention relates to a modulator system adapted to generate high voltage pulses suitable for supply across a high voltage load having a thermionic cathode, such as a magnetron. The modulator system comprises a high voltage DC PSU connected to a switching mechanism adapted to generate high voltage pulses from the high voltage DC PSU for application to a thermionic cathode of a high voltage load. The modulator system further comprises an isolation transformer; a heater PSU adapted to be connected to a cathode heater through the isolation transformer and to provide an AC current thereto. The modulator system further comprises a controller to receive pulse instruction signals and trigger generation of corresponding high voltage pulses by the switching mechanism, to calculate the estimated arrival time of a next pulse instruction signal, based on the time between previous pulse instruction signals, and disable the heater PSU for a preset time, commencing before the estimated arrival time of the next pulse instruction signal, such that no current is supplied from the heater PSU while current is supplied from the high voltage PSU.

A vacuum electron tube comprises at least one electron-emitting cathode and at least one anode arranged in a vacuum chamber, the cathode having a planar structure comprising a substrate comprising a conductive material, a plurality of nanotube or nanowire elements electrically insulated from the substrate, the longitudinal axis of the nanotube or nanowire elements substantially parallel to the plane of the substrate, and at least one first connector electrically linked to at least one nanotube or nanowire element so as to be able to apply a first electrical potential to the nanowire or nanotube element.

A vacuum electron tube comprises at least one electron-emitting cathode and at least one anode arranged in a vacuum chamber, the cathode having a planar structure comprising a substrate comprising a conductive material, a plurality of nanotube or nanowire elements electrically insulated from the substrate, the longitudinal axis of the nanotube or nanowire elements substantially parallel to the plane of the substrate, and at least one first connector electrically linked to at least one nanotube or nanowire element so as to be able to apply a first electrical potential to the nanowire or nanotube element.

The present invention relates to a modulator system adapted to generate high voltage pulses suitable for supply across a high voltage load having a thermionic cathode, such as a magnetron. The modulator system comprises a high voltage DC PSU connected to a switching mechanism adapted to generate high voltage pulses from the high voltage DC PSU for application to a thermionic cathode of a high voltage load. The modulator system further comprises an isolation transformer; a heater PSU adapted to be connected to a cathode heater through the isolation transformer and to provide an AC current thereto. The modulator system further comprises a controller to receive pulse instruction signals and trigger generation of corresponding high voltage pulses by the switching mechanism, to calculate the estimated arrival time of a next pulse instruction signal, based on the time between previous pulse instruction signals, and disable the heater PSU for a preset time, commencing before the estimated arrival time of the next pulse instruction signal, such that no current is supplied from the heater PSU while current is supplied from the high voltage PSU.