An X-ray diagnostic apparatus according to embodiments includes an X-ray tube assembly and a grid potential control circuitry. The X-ray tube assembly includes a filament that emits electrons, a target that generates X-rays by receiving the electrons, and a grid having a potential for adjusting a potential gradient around the filament. The grid potential control circuitry switches the potential of the grid to a potential where the potential gradient around the filament becomes greater than a potential gradient generated by a potential of the filament and a potential of the target.

Disclosed is an X-ray source, including: a cathode; an anode positioned on the cathode so as to face the cathode; emitters formed on the cathode; a gate electrode positioned between the cathode and the anode and including openings at positions corresponding to those of the emitters; an insulating spacer formed between the gate and the anode; and a coating layer formed on an internal wall of the insulating spacer, and including a material having a lower secondary electron emission coefficient than that of the insulating spacer.

Controlling total emission current of an electron emitting construct in an x-ray emitting device by providing a cathode, providing multiple active areas each active area having a gated cone electron source, including multiple emitter tips arranged in an array, a gate electrode, and a gate interconnect lead connected to the gate electrode, providing an x-ray emitting construct comprising an anode, the anode being an x-ray target, situating the x-ray emitting construct facing the active areas face each other, selecting a set of active areas, and activating selected active areas by conductively connecting a voltage source to their associated the gate electrode interconnect lead.

A bipolar grid may be positioned between a cathode and an anode. The bipolar grid may receive a positive grid voltage that corresponds to a voltage in an electric field between the cathode and the anode such that the grid does not interfere with an electron beam generated by an electron emitter of the cathode. The bipolar grid may receive a negative grid voltage to isolate the electron emitter such that the electron beam does not reach the anode.

The present invention relates to an apparatus for generating X-rays. It is described to produce (210) with a power supply (30) a voltage. A cathode (22) of an X-ray source (20) is positioned (220) relative to an anode (24) of the X-ray source. Electrons are emitted (230) from the cathode. Electrons emitted from the cathode interact (240) with the anode with energies corresponding to the voltage. X-rays are generated (250) from the anode, wherein the electrons interact with the anode to generate the X-rays. The X-ray source is controlled (260), such that a plurality of first X-ray pulses is generated each having a first X-ray flux, wherein the first X-ray pulses are temporally separated from each other. The X-ray source is controlled (270), such that a least one second X-ray pulse is generated having a second X-ray flux that is substantially less than the first X-ray flux, wherein the at least one second X-ray pulse is generated temporally between consecutive pulses of the first X-ray pulses.

Disclosed is an X-ray source, including: a cathode; an anode positioned on the cathode so as to face the cathode; emitters formed on the cathode; a gate electrode positioned between the cathode and the anode and including openings at positions corresponding to those of the emitters; an insulating spacer formed between the gate and the anode; and a coating layer formed on an internal wall of the insulating spacer, and including a material having a lower secondary electron emission coefficient than that of the insulating spacer.

The present invention relates to an apparatus for generating X-rays. It is described to produce (210) with a power supply (40) at least two voltages between at least one cathode (20) and an anode (30), wherein the at least two voltages comprises a first voltage and a second voltage. The at least one cathode is positioned relative to the anode. Electrons are emitted (220) from the at least one cathode. Electrons emitted from the at least one cathode are interacted (230) with the anode with energies corresponding to the at least two voltages. X-rays are generated (230) from the anode, wherein the electrons interact with the anode to generate the X-rays. First X-rays are generated when the power supply produces the first voltage and second X-rays are generated when the power supply produces the second voltage. The power supply is controlled (250), such that a ratio between the first X-rays and the second X-rays is controllable.

The disclosure relates to an image capture device comprising an electron receiving construct and an electron emitting construct, and further comprising an inner gap providing an unobstructed space between the electron emitting construct and the electron receiving construct. The disclosure further relates to an x-ray emitting device comprising an x-ray emitting construct and an electron emitting construct, said x-ray emitting construct comprising an anode, the anode being an x-ray target, wherein the x-ray emitting device may comprise an inner gap providing an unobstructed space between the electron emitting construct and the x-ray emitting construct. The disclosure further relates to an x-ray imaging system comprising an image capture device and an x-ray emitting device.

The present disclosure provides a method of manufacturing a carbon nanotube electron emitter, including: forming a carbon nanotube film; performing densification by dipping the carbon nanotube film in a solvent; cutting an area of the carbon nanotube film into a pointed shape or a line shape; and fixing the cutting area of the carbon nanotube film arranged between at least two metal members to face upwards with lateral pressure.

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.