The embodiments provide a thermionic emission device and a method for tuning a work function in a thermionic emission device is provided. The method includes illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating. The method includes collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member.

The embodiments provide a thermionic emission device and a method for tuning a work function in a thermionic emission device is provided. The method includes illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating. The method includes collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member.

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.

An electron generating apparatus includes a filament, a power supply configured to supply power to the filament so as to make the filament emit an electron, and a controller configured to repeatedly detect a value having a correlation with power supplied from the power supply to the filament, determine whether a state of the filament satisfies a notification condition, by using a plurality of detected values, and perform notification when the state satisfies the notification condition.

An electron generating apparatus includes a filament, a power supply configured to supply power to the filament so as to make the filament emit an electron, and a controller configured to repeatedly detect a value having a correlation with power supplied from the power supply to the filament, determine whether a state of the filament satisfies a notification condition, by using a plurality of detected values, and perform notification when the state satisfies the notification condition.

The present disclosure provides a filament power supply for an electron accelerator and an electron accelerator. The filament power supply includes: a rectifier circuit configured to convert a power frequency AC voltage signal into a DC voltage signal; an inverter circuit configured to convert the DC voltage signal into an AC voltage signal; a sampling circuit configured to sample the AC voltage signal to obtain a current sampling signal or a voltage sampling signal; a pulse width modulation control chip configured to adjust a pulse width modulation signal until a voltage of the current sampling signal is equal to that of a reference current signal, or a voltage of the voltage sampling signal is equal to that of a reference voltage signal; a modulation circuit configured to modulate the power frequency AC voltage signal to obtain a modulation signal and output the pulse width modulation signal and the modulation signal.

The present disclosure provides a filament power supply for an electron accelerator and an electron accelerator. The filament power supply includes: a rectifier circuit configured to convert a power frequency AC voltage signal into a DC voltage signal; an inverter circuit configured to convert the DC voltage signal into an AC voltage signal; a sampling circuit configured to sample the AC voltage signal to obtain a current sampling signal or a voltage sampling signal; a pulse width modulation control chip configured to adjust a pulse width modulation signal until a voltage of the current sampling signal is equal to that of a reference current signal, or a voltage of the voltage sampling signal is equal to that of a reference voltage signal; a modulation circuit configured to modulate the power frequency AC voltage signal to obtain a modulation signal and output the pulse width modulation signal and the modulation signal.

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.

Provided is an electron beam source for generating an electron beam comprising a cathode, an anode and a grid for regulating an electron beam current. The cathode has a base and a protrusion with sidewalls and a top surface. The base surface and the top surface are essentially flat. The base surface and the top surface are arranged at a predetermined distance from each other. The base is larger than the protrusion. The electron beam source further comprising a control unit adapted for changing an applied voltage to the grid for switching a spot size of the electron beam on a target surface between at least a first a first spot size corresponding to emission from the top surface of the cathode only and to a second spot size corresponding to emission from the top surface and the base surface of the cathode.

The embodiments provide a thermionic emission device and a method for tuning a work function in a thermionic emission device is provided. The method includes illuminating an N type semiconductor material of a first member of a thermionic emission device, wherein a work function of the N type semiconductor material is lowered by the illuminating. The method includes collecting, on one of the first member or a second member of the thermionic emission device, electrons emitted from one of the first member or the second member.