A device and method for creating beam formed X-Ray radiation using radio frequency (RF) modulated field emission X-ray sources is described. A radio frequency RF source generates a RF control signal which is supplied to an array of phase delay elements to generate multiple individually controlled phase delayed RF signals. These are then directly provided to each of a plurality of field emission sources (via a matching circuit) to generate a plurality of RF modulated electron current, or beam, each at the same frequency and phase delay of the phase delayed RF signals. Each of the electron beams impacts a target anode to generate X-rays also at the same frequency and phase delay of the phase delayed RF signals. By controlling each of the phase delay elements a beamformed X-ray radiation pattern can be generated.

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.

An electron source (2) for generating an electron beam (8) having a cathode (1) and an anode (4) in the form of a graphene layer (6, 12) epitaxially grown on a silicon carbide substrate (5). The invention is suitable for monolithic preparation of a miniaturized source of a high-energy focused electron beam, including its use as an on-chip X-ray source. All components can be prepared from or on a single silicon carbide chip.

It is a CNT device (1) (carbon-metal structure) equipped with a carbon nanotube layer (2) (CNT layer 2; same hereafter) on a metal pedestal (4). The metal pedestal (4) is brazed to the CNT layer (2) with a brazing material layer (3) interposed therebetween. When manufacturing the CNT device (1), firstly, the CNT layer (2) is formed on a heat-resistant textured substrate (6). Next, the metal pedestal (4) is brazed to the CNT layer (2) that is on the heat-resistant textured substrate (6) with the brazing material layer (3) interposed therebetween. Then, the metal pedestal (4) (and the CNT layer 2) is peeled off the heat-resistant textured substrate (6) to transfer the CNT layer (2) from the heat-resistant textured substrate (6) to the metal pedestal (4).

The present invention provides an emitter, which comprises carbon nanotubes and is excellent in the efficiency of electron emission, and an X-ray tube comprising the same.

A power supply circuit and a field emission electron source are provided. The power supply circuit includes: field effect transistors S.sub.i coupled in series via drains and sources in sequence, 1≤i≤n, i and n are natural numbers, n≥2, and a source of S.sub.1 is coupled to a negative electrode of a voltage source, and a drain of S.sub.n is used as an output terminal of the power supply circuit to couple to a load; a first group of diodes D.sub.1i coupled in series; a first group of resistors R.sub.1j, 2≤j≤n, and i and j are natural numbers; and a voltage control module configured to adjust an output voltage of the voltage source to cause a current passing through the load to be constant; the field effect transistors S.sub.i, 1≤i≤n, operate in a resistive region.

A power supply circuit and a field emission electron source are provided. The power supply circuit includes: field effect transistors S.sub.i coupled in series via drains and sources in sequence, wherein 1≤i≤n, n≥2, and wherein a source of S.sub.1 is coupled to a negative electrode of a voltage source, and a drain of S.sub.n is used as an output terminal of the power supply circuit to couple to a load; a first group of diodes D.sub.1i coupled in series; a first group of resistors R.sub.1j, 2≤j≤n; and a current feedback module configured to adjust an internal resistance of the field effect transistors S.sub.i, coupled in series in sequence, so as to cause a current passing through the load to be constant; wherein the field effect transistors S.sub.i, 1≤i≤n, operate in a constant current region.

A dielectric coated plasmonic photoemitter is provided. An aspect of the present photonic apparatus includes a conductive photoemitter including a dielectric material coating or layered on a metallic core. The dielectric material being configured to enhance a local optical field strength and current density of the photoemitter as compared to a bare photoemitter without the dielectric layer. The dielectric layered photoemitter being tunable to transmit photoemissions from corners thereof with different photonic characteristics depending on a laser wavelength pulse received.

Some example embodiments provide an x-ray tube for a stereoscopic imaging having an evacuated x-ray tube housing; an electron emitter apparatus in the x-ray tube housing, the electron emitter apparatus including a first field effect emitter with a first emitter surface and a second field effect emitter with a second emitter surface, at least one of the first emitter surface or the second emitter surface being segmented such that a portion of the at least one of the first emitter surface or the second emitter surface can be set relative to the respective overall emitter surface by selectively switching emitter segments of the at least one of the first emitter surface or the second emitter surface; an anode unit in the x-ray tube housing, the anode unit configured to generate x-ray radiation for the stereoscopic imaging as a function of electrons striking two focal points; and a control unit.

The present invention provides an emitter, which comprises carbon nanotubes and is excellent in the efficiency of electron emission, and an X-ray tube comprising the same.