31 results about "Relativistic electron beam" patented technology

Methods and apparatus are provided for modifying a free electron laser (FEL) to produce a non-diverging laser beam. A relativistic electron beam is converted to a Bessel beam in an FEL resonator with conical end mirrors, and the Bessel beam is coupled to the optical field within the laser resonator. The resultant laser beam is propagated with minimal divergence, and is wave corrected at the resonator output to produce a uniform intensity circular beam. The laser beam can be of smaller diameter than that of a conventional resonator due to its diffractionless propagation, which enables the magnetic structure gap within the resonator to be smaller, thus producing a higher optical gain.

A Free Electron Laser source includes: a fiber-based laser having a plurality of amplifying fibers wherein an initial laser pulse is distributed and amplified, and element for grouping together the elementary pulses amplified in the fiber in order to form an a single amplified global laser pulse; a laser plasma accelerator wherein the global laser pulse generates relativistic electron beams, a beam focusing system transporting electron beams from the laser plasma accelerator, an undulator wherein relativistic electron beams generate an electromagnetic beam, and a beam separator system, wherein the electron beam and the electromagnetic beam are separated.

The invention provides a small gamma ray source based on an all-optical laser plasma accelerator. The ray source includes a synchronous dual-output high-power laser system (200), a dual compression-delay system (12), a laser plasma accelerator (18), a particle beam focusing system (24), a scattered light focusing mirror (27) and a particle beam separate system. Wherein, an initial laser pulse is separated and amplified by the laser system (200) to generate two synchronous high-energy laser pulses (10, 11), and the two amplified laser pulses pass through a double compression-delay system (12) at Compressed in the time domain and appropriately delayed to form a pair of driving pulses (13)-scattering pulses (14), the driving pulses (13) pass through a laser plasma accelerator (18) to generate relativistic electron beams (21), particle beams The focusing system (24) is used to transmit the electron beam (21), the scattered light focusing mirror (27) is used to focus the scattered pulse (14) on the electron beam (21) to generate gamma rays (31), and the separation system is used to The electron beams (21) and gamma rays (31) are separated.

The invention discloses a non-relativistic electron beam induced dielectric waveguide-based terahertz radiation source. The non-relativistic electron beam induced dielectric waveguide-based terahertz radiation source includes a pulse laser light source used for emitting a laser pulse string, a frequency adjusting device used for adjusting the repetition frequency of the laser pulse string, an electron gun and a dielectric waveguide; the cathode of the electron gun is used for absorbing the laser pulse string and transmitting an electron beam cluster string; a size-adjustable electric field formed between the cathode and anode of the electron gun is used for accelerating the emitting of the electron beam cluster string into the dielectric waveguide; the dielectric waveguide is excited by the electron beam cluster string to form terahertz radiation; and the repetition frequency of the laser pulse string and the radiation frequency of the dielectric waveguide form resonance. With the non-relativistic electron beam induced dielectric waveguide-based terahertz radiation source adopted, energy conversion efficiency between the electrons and radiations of the terahertz radiation source can be effectively improved, radiation power can be improved, radiation frequency is adjustable. The cost of the terahertz radiation source can be reduced.

The invention relates to a fiber array cathode, and belongs to the field of a microwave source in the technical field of high-power microwaves. The fiber array cathode is formed by sleeving fiber bundle circumference arrays composed of porous array circular rings, U-shaped fiber bundles and circumference pads on a cathode substrate, wherein the two ends of each U-shaped fiber bundle are exposed at the side surface of a cathode to form a dense fiber array so as to replace velvet in a conventional cathode, the porous array circular rings have structural support and current conduction effects, and the dense fiber arrays formed by the fiber bundles mainly generate cathode plasma under the effect of a strong electric field and accordingly generate relativistic electron beams. The employed fiber bundles are generally carbon fiber bundles, glass fiber bundles or ceramic fiber bundles, or other materials with low emission thresholds and high temperature ablation resistance. Since the employed fiber bundle materials are better in high temperature ablation resistance than chemical fiber velvet in the conventional cathode, by use of the long-life fiber array cathode with the high temperature ablation resistance, the operation life of a MILO can be greatly prolonged.

The invention belongs to the field of masers and relates to a relativistic backward wave oscillator of a direct circular polarization TE11 mode. The relativistic backward wave oscillator comprises an annular cathode, angular partition double-pre-modulation chambers, angular partition slow wave structures, an output waveguide and a magnetic field coil. The annular cathode is at the most front end of the structure and emits an annular relativistic electron beam under the effect of high voltage pulse. The angular partition double-pre-modulation chambers, the angular partition slow wave structures, and the output waveguide are orderly arranged behind the annular cathode. The magnetic field coil is at the periphery of the annular cathode, the angular partition double-pre-modulation chambers, and the angular partition slow wave structures. The angular partition double-pre-modulation chambers and the slow wave structures are employed by the invention, two linearly polarized TE11 modes with the same frequency, similar amplitude and orthogonal polarization can be generated in two groups of structure. Through the offset of d / 4 of two groups of the double-pre-modulation chambers and the slow wave structures in an axial position, thus a 90-degree phase difference is introduced between the linearly polarized TE11 modes with orthogonal polarization, and the circular polarization TE11 mode is obtained in an output waveguide.

The invention, which belongs to the maser field, directly relates to a relativistic backward wave oscillator for generating a linearly polarized TE11 mode directly. The relativistic backward wave oscillator comprises an arc cathode, a reflector, an angular partition slow wave structure, an output waveguide and a magnetic field coil. The arc cathode is arranged at the front end of the relativistic backward wave oscillator; the reflector, the angular partition slow wave structure, and the output waveguide are arranged at the rear side of the arc cathode successively; and the magnetic field coil is installed at the periphery. According to the invention, with the nonaxisymmetrical arc cathode and the angular partition slow wave structure, the TE11 mode is excited directly. The reflector employs the dual-premodulation-cavity unit preferably and is used for carrying out premodulation on an arc relativistic electron beam and leaking the part of TE11 mode to enter the arc cathode zone, so that certain premodulation of the electron beam at the arc cathode zone is realized and thus the beam wave conversion efficiency is improved. Moreover, the oscillator has advantages of simple structure and high conversion efficiency; and the linearly polarized TE11 mode can be generated directly.

The invention provides a medical isotope generation method and device based on a laser wake-field accelerator. Interaction between super-strong and super-short lasers and plasma is utilized to generate a strong flow relativity electron beam. The electron beam is utilized to irradiate a high atomic number target to generate high-flow-strength bremsstrahlung gamma light. The bremsstrahlung gamma light bombards an interested object target to induce a ([gamma], xn+yp) photonuclear reaction or a ([gamma], [gamma]') optical excitation reaction, and object isotopes including gamma rays, electrons, positive electrons and [alpha] particle emitters are generated. By adopting the method provided by the invention, radio isotopes higher in activity are generated, and the cost is relatively low; in addition, the device provided by the invention is compact and convenient to carry, and the device is capable of being placed near a large-sized medical mechanism to be better applied to and serve radiation diagnosis, targeting treatment and other medical applications.

The invention discloses a cold cathode capable of generating multiple cylindrical intense relativistic electron beams. The cold cathode comprises a cylindrical structure which is made of a metal material high in conductivity and emission threshold and has the same outer diameter, and a cathode rod, a cathode rod transition ring, a cathode rod transition section, a cathode seat, a cathode column and a cathode bulb which are all coaxial and in excellent electric connection with each other. Due to even distribution of the surface field of the cathode bulb serving as an emitting component in the cold cathode, the cold cathode has even electron emission density and the emitted multiple cylindrical electron beams are distributed symmetrically about the own centers, respectively; under the action of an appropriate guide magnetic field, the electron beams are not prone to collide with the wall of a multiple-beam drift tube due to that the electron beams rotate around the own centers in the transmission process in the drift tube; the transmission efficiency is high, the space configuration of the electron beams in the drift tube is kept unchanged, and the beam conversion efficiency is improved.

A laser-plasma-based acceleration system includes a focusing element and a laser pulse emission directing a laser beam to the focusing element to such that laser pulses transform into a focused beam and a chamber defining a nozzle having a throat and an exit orifice, emitting a critical density range gas jet from the exit orifice for laser wavelengths ranging from ultraviolet to the mid-infrared. the critical density range gas jet intersects the focused beam at an angle and in proximity to the exit orifice of the nozzle to define a point of intersection between the focused beam and the critical density range gas jet. In intersection with the critical density range gas jet, the pulsed focused beam drives a laser plasma wakefield relativistic electron beam. A corresponding method of laser-plasma-based acceleration is also described. The critical density range may include 2×1020 cm−3 to 5×1021 cm−3.

The invention relates to a microwave source device in the field of high-power microwaves, and is a low-frequency slow-wave structure based on metamaterials, comprising a first metamaterial resonance unit, a second metamaterial resonance unit and a circular waveguide; the first metamaterial resonance unit and the The second metamaterial resonant unit is arranged in a 45-degree rotational coupling to form a single period of the slow-wave structure; the present invention has the following technical advantages: using a metamaterial-based slow-wave structure, it can work below the cut-off frequency of a hollow metal circular waveguide of the same size , has the advantage of lateral miniaturization; due to the sub-wavelength characteristics of metamaterials, the slow-wave structure has a shorter period and has the advantage of miniaturization in the axial direction; due to the local field enhancement effect of the metamaterial slow-wave structure, the slow-wave structure has a higher coupling impedance, The device has the advantage of higher beam-wave interaction efficiency; the strong electromagnetic coupling between the slow-wave structures of metamaterials has a strong modulation of the relativistic electron beam, which makes the device have a shorter start-up time.

The invention discloses an X wave band over-mode relativistic klystron amplifier, which comprises an annular cathode, a resonant reflector, an input cavity, a first section of drift tube, a wave absorbing material, a buncher cavity, a second section of drift tube, an output cavity and a magnetic field coil, wherein the annular cathode is arranged at the most significant end of the structure and emits annular relativistic electron beams outwards under the action of high voltage pulse, the resonant reflector, the input cavity, the first section of drift tube, the wave absorbing material, the buncher cavity, the second section of drift tube and the output cavity are sequentially arranged at rear of the annular cathode, the magnetic field coil is installed at the periphery of the whole structure, the working mode of the resonant reflector, the input cavity, the buncher cavity and the output cavity is a TM02 mode, and the first section of drift tube and the second section of drift tube can transmit a TM01 mode. The X wave band over-mode relativistic klystron amplifier can produce high power X wave band microwave.