A beam injector may include a cathode emitter to emit electrons and an electrode to bias at least a portion of the electrons to remain on the cathode emitter and focus the emitted electrons into an electron beam. The beam injector may also include a resistor coupled between the cathode emitter and the electrode and configured to allow self-regulation of a voltage potential on the electrode based at least in part on a current of the electron beam.

An embodiment of the inventive concept provides an X-ray tube including a chamber having a hollow pillar shape using a first axis as a central axis, a cathode electrode disposed on a bottom surface of the chamber, an emitter provided at a position at which the cathode electrode meets the first axis, an anode electrode including a through-hole using the first axis as a central axis and a target layer inclined to the first axis, a gate electrode disposed between the cathode electrode and the anode electrode and having an opening exposing the emitter, a focusing electrode disposed between the gate electrode and the anode electrode, a window spaced apart from the target layer of the anode electrode, and a window electrode provided on a top surface of the chamber to fix a side surface of the window. Here, the window electrode is grounded.

A device and method for creating controlled radio frequency (RF) modulated X-ray radiation is described. The device includes an anode housed within a vacuum enclosure which acts to accelerate and convert an electron beam into X-ray radiation. A RF enclosure is housed within the vacuum enclosure and houses a field emission device, such as a carbon nanotube field emission device or similar cold cathode field emission device. The field emission device is biased to emit the electron beam from a field emission cathode via an extraction electrode in the RF enclosure towards the anode. Additionally an RF impedance matching and coupling circuit is connected electrically to the field emission device. The field emission device is thus directly driven with a RF signal to produce an RF modulated electron current to produce an RF modulated X-ray radiation.

The X-ray imager combines a pulsed X-ray source with a time-sensitive X-ray detector to provide a measure of ballistic photons with a reduction of scattered photons. The imager can provide a comparable contrast-to-noise X-ray image using significantly less radiation exposure than conventional X-ray imagers, notably about half of the radiation.

An X-ray diagnostic apparatus according to an embodiment includes: an X-ray tube including a target configured to generate X-rays in response to emission of electrons thereto, a plurality of filaments configured to emit electrons into substantially the same position on the target, and a grid used in common among the plurality of filaments; intermediate potential setting circuitry configured to set intermediate potential in a position between the plurality of filaments and the target by using the grid; and filament potential controlling circuitry configured to change one or more filaments selected from among the plurality of filaments to emit the electrons to the target, by controlling potential levels of the plurality of filaments with respect to the intermediate potential for each filament, in conjunction with switching of X-ray tube voltage.

A system for grid control of an electromagnetic ray tube is provided. The system includes a power source, a rectifier, and a grid conductor. The power source is disposed apart from the electromagnetic ray tube and operative to generate an AC current. The rectifier is integrated into the electromagnetic ray tube and electrically coupled to a grid electrode of the electromagnetic ray tube. The grid conductor electrically couples the power source to the rectifier. The rectifier is operative to convert the AC current to a DC current that powers the grid electrode.

Some embodiments include a system, comprising: a high voltage enclosure; a cathode disposed in the high voltage enclosure; an anode disposed in the high voltage enclosure; a plurality of grids disposed in the high voltage enclosure between the cathode and the anode; a voltage source configured to generate a common grid voltage; and a voltage divider disposed in the high voltage enclosure, configured to generate a plurality of grid voltages based on the common grid voltage, and configured to apply at least two of the grid voltages to the grids.

Some embodiments include a system, comprising: an enclosure configured to enclose a vacuum; a cathode disposed within the enclosure; an anode disposed within the enclosure configured to receive a beam of electrons from the cathode; a motor disposed within the enclosure and configured to rotate the anode in response to a drive input; and a circuit electrically connected to the drive input, and configured to generate a phase signal based on a voltage of the drive input and a current of the drive input, the phase signal indicating a phase difference between the voltage of the drive input and the current of the drive input.

A radiation tube that is used in a radiation source for radiography includes: an electron emitting unit that includes a cathode unit having an emitter electrode which emits electrons and a gate electrode; an anode unit that has an anode surface facing the cathode unit and collides with the electrons to generate radiation; a constant voltage supply unit that supplies a constant driving voltage to the gate electrode; and a vacuum tube that accommodates the constant voltage supply unit, the electron emitting unit, and the anode unit.

An x-ray tube includes a thermionic cathode generating an electron beam propagating from the cathode to a target along a beam axis. The x-ray tube has apertures in the form of a control electrode with a first aperture opening, a focusing electrode with a second aperture opening and a beam shaping electrode with a third aperture opening. The first aperture opening is smaller than the emission surface and has a contour rotationally symmetric with respect to the beam axis. The second aperture opening is larger than the first aperture opening and has a contour rotationally symmetric with respect to the beam axis. The third aperture opening has a contour which is aligned with an xy plane and non-rotationally symmetric with respect to the beam axis. The X-ray tube has a simple structure for generating an electron beam where the number of electrons can be varied easily over a wide range.