A pulsed generator of electrically charged particles includes a vacuum chamber; wherein the vacuum chamber is configured to maintain an internal operating pressure between 10-6 mbar and atmospheric pressure; the vacuum chamber is configured to accommodate a photocathode and an anode, the photocathode and the anode being separated by an adjustable distance less than or equal to 30 mm; the vacuum chamber includes a window enabling pulsed light to reach firstly a rear face of the photocathode; the anode is arranged downstream of the photocathode and has an orifice suitable for the passage of electrically charged particles; the generator of electrically charged particles includes a system to apply a difference in potential between the photocathode and the anode, the voltage being configured to accelerate the charged particles.

[Object] To provide an electron source that is lightweight, simple in configuration, and capable of suppressing characteristic degradation or recovering characteristics without causing an increase in power consumption.

[Solving Means] A CNT electron source includes: a CNT emitter 32 for emitting electrons; a gate electrode 33 for extracting electrons from the CNT emitter 32; and a gate power supply connection switching relay 37a and a CNT emitter grounding switching relay 37b that cause the gate electrode 33 to emit electrons to irradiate the CNT emitter with electrons.

[Object] To provide an electron source that is lightweight, simple in configuration, and capable of suppressing characteristic degradation or recovering characteristics without causing an increase in power consumption. [Solving Means] A CNT electron source includes: a CNT emitter 32 for emitting electrons; a gate electrode 33 for extracting electrons from the CNT emitter 32; and a gate power supply connection switching relay 37a and a CNT emitter grounding switching relay 37b that cause the gate electrode 33 to emit electrons to irradiate the CNT emitter with electrons.

Provided herein is a field emission device. The field emission device includes a cathode which is connected to a negative power supply and emits electrons, an anode which is connected to a positive power supply and includes a target material receiving the electrons emitted from the cathode, and a ground electrode which is formed to face the anode and has an opening through which the electrons emitted from the cathode pass. The ground electrode is grounded so that when an arc discharge occurs due to high voltage operation of the anode, electric charge produced by the arc discharge is emitted to a ground.

A field emission cathode device includes a cathode element having a field emission surface and an adjacent gate electrode clement defining a first gap therebetween. A gate voltage applied to the gate electrode clement causes the field emission surface to emit electrons that are accelerated through the gate electrode element. The gate electrode element is disposed between the cathode element and an anode element. the anode element having an anode voltage applied thereto to attract the electrons emitted through the gate electrode element. A tuning electrode element is disposed between the gate electrode element and the anode element. The tuning electrode element has a tuning voltage applied thereto to decelerate the electrons directed through the gate electrode element and to direct the electrons therethrough toward the anode element. An associated method of forming a field emission cathode device is also provided.