A method includes performing by a processor: estimating a total cathode space current for a thermionic vacuum tube having at least one grid and a plate, such that at least one amplification factor associated with the at least one grid is determined by a polynomial based on a variable that represents at plurality of voltages associated with the at least one grid and the plate, the variable being heuristically determine. Transitions between positive and negative grid operation may experience a step change in estimated current value caused by the inclusion or elimination of grid current. A part of the grid current may be added back into the plate current during transition. This small contribution to plate current may gradually diminish as tube operation moves farther away from the transition boundary.

To suppress both influence of electron emission from a cathode side surface and consumption of energy to be supplied to a heater, while being provided with a grid, an electron gun of the present invention includes: a cathode capable of emitting electrons by heating; a grid capable of controlling the electron emission; and a cathode shield which is an conductor including a material portion located in the vicinity of a side surface of the cathode and facing at least a portion of the side surface via a gap or a heat insulating material, and not being made in direct physical coupling nor in direct physical contact with the cathode.

A cathode device includes an emitter tip for generating electrons. An elongate heater is included having proximal and distal ends. The emitter tip can be located at the distal end of the heater. Two spaced apart legs can extend away from the distal end of the heater, terminating at the proximal end and forming an elongate slot therebetween. Two electrical contacts can compressively engage respective opposite outer surfaces of the two legs at the proximal end of the heater to mechanically secure and electrically connect the two legs of the heater to respective electrical contacts at a junction that is at a location spaced away from the emitter tip to keep the junction cooler.

The present disclosure is related to a microwave source. The microwave source may include a cathode heater and a thermionic emitter. The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater. At least a portion of the second component of the cathode heater may be in contact with the thermionic emitter.

The present disclosure is related to a microwave source. The microwave source may include a cathode heater and a thermionic emitter. The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater. At least a portion of the second component of the cathode heater may be in contact with the thermionic emitter.

An emitter includes an insulator, a pair of terminals attached to the insulator separately from each other, at least one filament attached between the pair of terminals in an arch shape, and an electron source fixed to the filament. The filament has bent portions between a contact with respect to the electron source and contacts with respect to the terminals. A device is provided with the emitter.

In order to provide a stable hexaboride single-crystal field emission electron source capable of heat-flashing, this field emission electron source is provided with a metal filament, a metal tube joined thereto, a hexaboride tip that emits electrons, and graphite sheets that are independent of the metal tube and the hexaboride tip. The hexaboride tip is arranged so as not to be in structural contact with the metal tube due to the graphite sheets. The hexaboride tip, the graphite sheets, and the metal tube are configured so as to be mechanically and electrically in contact with one another.

To suppress both influence of electron emission from a cathode side surface and consumption of energy to be supplied to a heater, while being provided with a grid, an electron gun of the present invention includes: a cathode capable of emitting electrons by heating; a grid capable of controlling the electron emission; and a cathode shield which is an conductor including a material portion located in the vicinity of a side surface of the cathode and facing at least a portion of the side surface via a gap or a heat insulating material, and not being made in direct physical coupling nor in direct physical contact with the cathode.

The present disclosure is related to a microwave source. The microwave source may include a cathode heater and a thermionic emitter. The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater. At least a portion of the second component of the cathode heater may be in contact with the thermionic emitter.

The present disclosure is related to a microwave source. The microwave source may include a cathode heater and a thermionic emitter. The cathode heater may include a first component, and a second component enclosing at least a portion of the first component. The thermionic emitter may be configured to release electrons when the thermionic emitter is heated by the cathode heater. At least a portion of the second component of the cathode heater may be in contact with the thermionic emitter.