RU2647489C1 - Electronic unsoldered gun for electron flow and x-ray radiation discharge from vacuum region to atmosphere - Google Patents

Abstract

FIELD: electrical engineering; X-ray engineering.

SUBSTANCE: invention relates to electronic and X-ray technology, namely, to electron guns made to inject high-energy electrons and X-rays from the vacuum region of the gun into the atmosphere or other medium, and can be used in plasma chemistry, biology, medicine, semiconductor and quantum electronics, as well as in other fields of technology. Electronic ulsoldered gun includes a cathode, metal casing, at the end of which coaxially with the cathode there is a non-uniform thickness of the electron exit window with blind holes, including a diamond plate. On the surface of the window facing the cathode, a non-uniform current-conducting coating is applied electrically connected to the casing, wherein the coating outside the region of the blind holes comprises a heavy metal for generating X-rays, and the electron flow is led out through the diamond plate and blind holes.

EFFECT: expansion of the electron-sealed gun functionality due to additional generation of X-ray radiation while maintaining a high average gun power density.

8 cl, 2 dwg

Description

The invention relates to electronic equipment and X-ray technology, in particular to electron guns intended for injection of high-energy electrons and X-rays from the vacuum region of the gun into the atmosphere or other medium, and can be used in plasma chemistry for the polymerization and acceleration of slow-moving chemical reactions, in biology and medicine for efficient processing of objects, semiconductor microelectronics to create new structures, in quantum electronics for electroionization lasers, and in other areas of technology.

High-energy electrons and x-rays act differently on matter. For example, when a solid or liquid phase of a substance is irradiated, electrons are predominantly absorbed in a thin surface layer, while x-ray radiation penetrates much deeper into the volume. When a plasma is exposed to a plasma, a high-energy electron flux mainly gives its energy to free plasma electrons, exciting various types of instabilities in it, while X-ray radiation is mainly absorbed by atoms and ions, more precisely their bound electrons. Therefore, for a more complete and effective effect on the substance, it is desirable to treat it with both electrons and x-ray radiation, and at the same time.

Basically, in existing electronically sealed cannons, the output of a high-speed stream of electrons from the vacuum region of the gun to the outside is carried out through a thin metal foil, during the passage of which only a small part of the electron energy is converted to x-ray radiation. In addition, the metals used as the foil material are titanium, beryllium / Simonov K.G. Electronic sealed guns. M .: Radio and Communication, 1985, 125 pp. / The maximum energy of quanta of characteristic x-ray radiation does not exceed 5 keV, therefore they have weak penetrating power / Physical quantities: Reference / A.P. Babichev, N.A. Grandmother and others. Ed. I.S. Grigoryeva. - M.: Energoatomizdat, 1991 .-- 1232 p. /.

To increase the quanta energy of the characteristic x-ray radiation, it is necessary to use heavy metals, such as tungsten and molybdenum, which are used in x-ray sources / ibid / in the electronically sealed gun as a foil material.

Replacing a beryllium and titanium foil with a tungsten or molybdenum foil will increase the energy of quanta of the characteristic x-ray radiation, but will reduce the current and reduce the energy of the electron flux transmitted through the foil, since the depth of penetration of electrons into the substance is inversely proportional to its density / Kovalenko V.F. Thermophysical processes and electrovacuum devices. M., Sov. Radio,. 1975, 216 pp. /.

At the same time, the electron beam and X-ray radiation can be removed into the atmosphere or other medium using an X-ray tube operating on a cross-beam / RF Patent No. 2567848 /, by reducing the thickness of the target for this.

The disadvantage of this solution will be a decrease in the intensity of x-ray radiation due to the incomplete use of the electron beam to obtain x-ray radiation.

Thus, it is possible to remove simultaneously a high-speed electron beam and x-ray radiation into the atmosphere or other medium from an electronically sealed gun or a source of X-ray radiation operating on a cross-beam, but an increase in the fraction of one component occurs due to a decrease in the fraction of the other, i.e. such a technical solution is inefficient.

The closest in technical essence and the achieved result is an electronically sealed gun for removing the electron beam from the vacuum region of the gun into the atmosphere or other gas medium, including a housing in the form of a metal pipe, in the end part of which there is an electron exit window made of a heat-conducting dielectric, in particular diamond, of variable thickness over the window area and vacuum-tightly connected to the supporting base of the window, conductive coating on the window surface facing the cathode and electrically ki associated with the support base and the housing box gun disposed in the housing coaxially to the cathode, the longitudinal axis of which is parallel to the longitudinal axis of the output window electron focusing electrodes and / Patent RF №2590891 /.

This technical solution when using diamond allows you to increase the transmitted average power density up to 50 W / cm ² and even work in continuous mode.

The disadvantage of this gun is the low energy of the quanta of characteristic x-ray radiation, and therefore their low penetration, due to the use of a conductive coating of materials with low atomic weight, for example, graphite / Physical quantities: Reference / A.P. Babichev, N.A. Grandmother and others. Ed. I.S. Grigoryeva. - M.: Energoatomizdat, 1991 .-- 1232 p. /.

The objective of the invention is to remedy the above drawback.

The technical result of the proposed technical solution is to expand the functionality of the electronically soldered gun due to the additional generation by it of characteristic x-ray radiation with high energy quanta, while maintaining the parameters of the electron beam of the prototype.

This problem is solved, and the technical effect is achieved due to the fact that in the electronically sealed gun to remove the electron beam from the vacuum region of the gun into the atmosphere or other gaseous medium, including the casing in the form of a metal pipe, an electron exit window is located in the end part containing at least one diamond plate and vacuum-tightly connected to the supporting base of the window, a conductive coating deposited on the surface of the window facing the cathode and electrically connected to the supporting base of the window and pusom gun disposed in the housing coaxially to the cathode, the longitudinal axis of which is parallel to the longitudinal axis of the output window of electrons and focusing electrodes, a conductive coating is inhomogeneous over the area of the window portions with containing heavy metal / ly and disposed preferably in the region of maximum thickness of the window.

The thickness of the sections of the conductive coating containing heavy metal and located in the areas of maximum window thicknesses is greater than or equal to the depth of penetration of electrons from the cathode into the conductive coating, and the thickness of sections of the conductive coating on a diamond plate in the areas of minimum window thicknesses is less than the depth of penetration of electrons from the cathode into the conductive coating .

A conductive coating is electrically connected to the supporting window base and the gun body on the surface of the exit window, facing away from the cathode.

The cathode is made in the form of two groups of cells, one of which is placed azimuthally symmetrically to the areas of the cover of the output window containing heavy metal, and the other is placed azimuthally symmetrically to the regions of the minimum thicknesses of the output window.

The window is made of either a single diamond plate, non-uniform in thickness, or contains a plate with through holes made of a heat-conducting material with a thermal conductivity of more than 4 W / cm⋅K and vacuum-tightly connected to each diamond plate, while the plate with through holes is made from diamond-silicon carbide composite.

In FIG. 1 is a schematic sectional view of an electronic sealed gun.

In FIG. 2- is a sectional view of a window structure.

The electron gun consists of a cathode assembly 1, including a cathode and focusing electrodes and mounted on a cathode holder 2 through a high-voltage insulator 3 at the end of the housing 4. A diamond window 5 is installed coaxially to the cathode assembly 1 in the form of a plate with blind holes 6 for electron output vacuum-tightly connected to the support base of the window 7. Base 7 is vacuum-tightly connected to the body of the gun 4. On the surface of the window 5, facing the inside of the gun, a conductive heterogeneous coating is applied from the mother la with a small atomic weight 8 in the blind hole 6 and made of a material with a metal with high atomic weight and consequently high energy photons characteristic radiation (heavy metal) 9 in the portions of greater thickness window. Both coating materials 8 and 9 are electrically connected to each other, with the support base of the window 7 and the gun body 4.

The electron gun works as follows.

At the cathode, for example, direct heat, and focusing electrodes made, for example, of molybdenum, the cathode assembly 1 from a high voltage power source (s) (not shown), a voltage negative relative to the ground is supplied. The gun body 4, made, for example, of stainless steel, is grounded. Inside the gun, between the cathode assembly 1 and the casing 4, an electric field is created that generates a high-speed stream of electrons emitted by the cathode and directs it to the conductive coating 8, 9 of the window 5. The conductive coating 8 is made, for example, of graphite 8, and the conductive coating 9 made, for example, of tungsten.

The stream of electrons that hit the graphite conductive coating 8 passes through it almost without loss and thin sections of the diamond window in the region of blind holes and goes out into the atmosphere. The flow of electrons that hit the conductive coating of tungsten 9 is completely inhibited in it, generating x-ray radiation that passes through the x-ray transparent diamond / ibid /.

The electrons intercepted by the diamond window after their accumulation leave through the conductive coating 8 to the ground, as described in the prototype.

Unlike the prototype, where the electrons that entered the thick areas of the diamond window were completely intercepted by them, converting their energy only to heat, in the proposed technical solution these electrons were completely intercepted by a tungsten coating, additionally generating x-rays with high energy quanta that pass through the diamond as stated above.

For more efficient operation of the device, a conductive coating containing heavy metal (s) and deposited on thick sections of the window is made thicker than the depth of penetration of electrons emitted by the cathode into this coating, and a conductive coating deposited on thin sections is less.

To exclude the influence of a negative window charge on the operation of the electron gun on the external surface facing the cathode, the window surface is coated with a conductive coating electrically connected to the supporting base of the window and the gun body. Without this conductive coating, positive ions that have arisen in the atmosphere during the passage of the electron beam will intensively bombard the window under the influence of its negative charge. The application of a conductive coating on the outer surface of the window shields its negative charge, and therefore eliminates the specified bombardment.

To operate the device, mainly as an electron gun or as an x-ray source, the cathode is made in the form of two groups of individual independent cells, one of which is placed azimuthally symmetrically to portions of the output window containing heavy metal, and the other is placed azimuthally symmetrically to the blind window openings. The work of a group of cells located opposite the window sections containing heavy metal leads to the generation of X-ray radiation, and the work of another group of cells leads to the generation of high-energy electrons.

To improve the reliability of the device during operation, the window is made of two plates: solid thin diamond and thick of heat-conducting material with a thermal conductivity of more than 4 W / cm⋅K, in particular diamond-silicon-silicon composite, with through holes, while both plates are vacuum tightly connected between by myself.

Thus, the proposed technical solution extends the functionality of the electronically soldered gun due to the additional generation by it of characteristic x-ray radiation with high quantum energy, while maintaining the parameters of the electron beam at the prototype level.

Claims (8)

 1. An electronically sealed gun for outputting an electron stream from the vacuum region of the gun into the atmosphere or other gas medium, including a casing in the form of a metal pipe, in the front part there is an inhomogeneous electron exit window containing at least one diamond plate and a vacuum tightly connected to the supporting base of the window, a conductive coating deposited on the window surface facing the cathode and electrically connected to the supporting base of the window and the gun body, located in the housing coaxially with the cathode, whose longitudinal axis is parallel to the longitudinal axis of the electron exit window, and focusing electrodes, characterized in that the conductive coating is made inhomogeneous over the window area with portions containing at least one of the heavy metals and located in the regions of maximum window thicknesses. 2. An electronic sealed gun according to claim 1, characterized in that the thickness of the sections of the conductive coating containing heavy metal and located in the regions of maximum window thicknesses is greater than or equal to the penetration depth of electrons from the cathode into the conductive coating. 3. The electronically sealed-off gun according to claim 1, characterized in that the thickness of the sections of the conductive coating on the diamond plate in the regions of minimum window thickness is less than the depth of penetration of electrons from the cathode into the conductive coating. 4. The electronic sealed-off gun according to claim 1, characterized in that a conductive coating is electrically connected to the supporting base of the window and the gun body on the surface of the exit window facing away from the cathode. 5. The electronic sealed-off gun according to claim 1, characterized in that the cathode is made in the form of two groups of cells, one of which is placed azimuthally symmetrically to the portions of the output window covering containing heavy metal / s, and the other is placed azimuthally symmetrically to the regions of the minimum thicknesses of the output window. 6. The electronically sealed-off gun according to claim 1, characterized in that the electron exit window is made of one diamond plate, non-uniform in thickness. 7. The electronic sealed-off gun according to claim 1, characterized in that the electron exit window comprises a plate with through holes made of a heat-conducting material with a thermal conductivity of more than 4 W / cm⋅K and vacuum-tightly connected to each diamond plate. 8. The electronic sealed-off gun according to claim 7, characterized in that the plate with through holes is made of a diamond-silicon carbide composite.

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