RU177198U1 - X-ray generator - Google Patents

Abstract

A useful model of an x-ray generator relates to the field of x-ray technology and can be used to generate x-rays used in radiography and fluoroscopy, x-ray flaw detection, x-ray diffraction and x-ray fluorescence analyzes. The generator contains a pyroelectric crystal, a Peltier element, heat conductors, a beryllium window for outputting the generated radiation, and a sealed enclosure. The case is made of titanium and has a highly developed inner surface. The proposed technical solution will extend the life of devices of this kind, and in case of leakage, which can lead to temporary abnormal leakage, the highly developed inner surface of the titanium case adsorbs molecules and restores the necessary pressure for normal operation of the device.

Description

A useful model of an x-ray generator relates to the field of x-ray technology and can be used to generate x-rays used in radiography and fluoroscopy, x-ray flaw detection, x-ray diffraction and x-ray fluorescence analyzes.

A device is known under the name "High-energy crystalline generator and its use" described in US patent No. 7741615 B2 (publ. 06/22/2010). The invention is a high-energy generator of electron and ion beams based on a ferroelectric crystal. This is ensured by heating the crystal or by the action of external electromagnetic fields. Heating or cooling a ferroelectric crystal in a vacuum causes a bound charge that accumulates on the faces of the crystal, which is normal to polarization. A slight change in temperature leads to the formation of a significant electrostatic field and the emission of high energy.

A device is known under the name "X-ray generator using a hemimorphic crystal" described in US patent No. 7729474 B2 (publ. 06/01/2010). This work describes the device of an x-ray generator based on the use of a hemimorphic crystal, which was subjected to temperature exposure. When a crystal is heated or cooled using a Peltier element, a strong electric field is formed around the crystal. The technical result of such a device is the ability to create a stable x-ray flux for a long time without the use of bulky equipment.

Also, a device is known under the name "X-ray generator using a crystal of a hemimorphic form" described in JP patent No. 2005285575 A (publ. October 13, 2005). The developed device is designed to generate x-ray radiation using a hemimorphic crystal, such as LiNbO3 or LiTaO3 and a Peltier element, which allows you to influence the temperature of the crystal and thereby change the magnitude and direction of the polarization vector, which indicates the region where the charge is induced. As a result of the implementation of this mode of operation of the device, a potential difference is formed, which ensures the formation of x-ray radiation. The technical result of such an invention consists in the continuous generation of x-rays.

There are devices designed to create and maintain a high vacuum, due to the adsorption of molecules penetrating into the evacuated volume — getters, getter elements, which are included in vacuum devices, systems as separate structural elements. In order for such a device to fulfill its function of maintaining a high vacuum, it must be activated. The getter, getter element is activated when it is heated to a certain temperature.

One of the known devices aimed at neutralizing molecules that penetrate the device over time and worsen the vacuum is the “Getter element” described in patent RU No. 2379780 (publ. 01/20/2010). The invention consists of a porous gettering substance, on the surface of which a non-continuous metal film is applied. On two opposite sides of the getter element, ohmic contacts are made to the extreme regions of the non-continuous metal film, to which an electric current is supplied. Since the metal film is not continuous, then through areas not covered with metal, the absorption of residual gases in the vacuum volume occurs, which ensures high vacuum.

Known "Porous getter devices with reduced particle loss and a method for their manufacture" described in patent RU No. 2253695 (publ. 10.06.2005,). The invention relates to a method for the manufacture of porous getter (getter) devices and is aimed at providing and maintaining a high vacuum by forming a coating on the surface of a porous getter body with a thickness of about 0.5 microns.

Also, the invention is known under the name "Nanocomposite getter structure and method for its preparation" described in patent RU No. 2523718 (publ. July 20, 2014). The technical solution designed to maintain vacuum in various devices is a silicon substrate with crystallization centers on the surface on which a layer of active metal or alloy with a developed surface is grown, which ensures sorption ability and maintaining a high vacuum.

A device is known under the name "COOL-X X-ray Generator" (http://amptek.com/products/cool-x-pyroelectric-x-ray-generator/), which is manufactured in the USA by Amptek. COOL-X is a miniature x-ray generator that uses a pyroelectric crystal to generate electrons. The sealed metal casing of the source has a thin beryllium window designed to output x-rays. COOL-X does not contain radioisotopes or high power supplies. This is an autonomous, solid-state system that generates x-rays when the crystal is thermally exposed. When used periodically for approximately 1-3 hours per day, the estimated life of the COOL-X will be more than 1000 hours. Continuous use of COOL-X will shorten its life by up to about 200 hours.

The common disadvantages of the known technical solutions include the deterioration of the vacuum during operation of the device, which leads to a decrease in the intensity of the generated radiation, as well as the inability to improve the vacuum without the use of energy or the use of additional structural elements.

The task to which the proposed technical solution is directed is to create a device that allows the generation of x-ray radiation, the intensity of which would change slightly throughout the entire period of operation, thereby increasing the life of the device.

The problem is solved using the proposed x-ray generator containing a pyroelectric crystal, a Peltier element, heat pipes, a beryllium output window of the generated radiation and a sealed housing, the housing being made of titanium and has a highly developed inner surface.

The advantage of the proposed utility model is the generation of x-ray radiation and a slight change in its intensity, due to the stable maintenance of a high level of vacuum throughout the entire period of operation of the device. This is achieved due to the adsorption of molecules by the highly developed inner surface of the sealed titanium case, which serves as a getter element, which allows a long time to maintain the initial radiation intensity and increases the life of the devices. In this case, there is no energy consumption to maintain the vacuum level in the system and additional structural elements are not required.

The technical result consists in the generation of x-ray radiation and a slight change in its intensity throughout the operation of the device, which increases the life of the device. This is achieved through continuous adsorption of gas molecules that adversely affect the vacuum, the highly developed inner surface of the sealed titanium case, the proposed x-ray generator, which performs the function of a getter element.

The utility model is illustrated in the drawing.

FIG. 1 is a functional diagram of a device.

The device consists of a heat pipe 1, a Peltier element 2, a heat pipe 3, a pyroelectric crystal 4, a beryllium output window of the generated radiation 5 and a sealed titanium case 6 with a highly developed inner surface 7 (Fig. 1).

Pyroelectric crystal 4, for example, lithium niobate (LiNbO3) or lithium tantalate (LiTaO3), is a cylinder with a height and diameter of about 10 mm. The pyroelectric crystal 4 is attached to the heat conduit 3 using electrically conductive glue. The heat pipe 3, located between the pyroelectric crystal 4 and the Peltier element 2, is a plate whose surface area is larger than the surface area of the Peltier element 2. The heat pipe 3 must be earthed, and its design depends on the shape of the pyroelectric crystal 4, because through the heat pipe 3, heat is transferred between the Peltier element 2 and the pyroelectric crystal 4. The Peltier element 2 changes the temperature of the pyroelectric crystal 4 and is connected to the heat conductor 1 s using heat transfer glue. The heat pipe 1 is a metal plate and removes excess heat from the pyroelectric crystal 4. The beryllium window for outputting the generated radiation 5 is a thin beryllium foil with a thickness of about 0.1 mm. The sealed titanium case 6 of the x-ray generator having a highly developed inner surface 7 formed by sandblasting, annealing and subsequent chemical etching is made of high-purity titanium. The highly developed inner surface 7 of the sealed titanium body 6 adsorbs gas molecules when heated, and acts as a getter element.

To generate X-rays, a Peltier element 2 is supplied with power. Due to the arising Peltier effect, the temperature of the lower surface of the pyroelectric crystal 4 changes. In this case, due to the pyroelectric effect, opposite in sign charges are formed on the surfaces of the pyroelectric crystal 4, which are sources of the electric field used to accelerate electrons and ionize residual gas molecules. The heat released from the opposite side to the heat conductor 3 and the pyroelectric crystal 4, the heated side of the Peltier element 2, is absorbed by the heat conductor 1. When the pyroelectric crystal 4 is bombarded with accelerated electrons, x-ray radiation is generated, part of which passes through the beryllium output window of the generated radiation 5 and is detected by the detector. During operation of the x-ray generator, due to leakage of air molecules and sublimation of the substance from the internal surfaces of the device, the vacuum level decreases (gas pressure rises), which leads to a significant change in the intensity of the generated radiation. Due to the operation of the Peltier element 2, the highly developed inner surface 7 of the sealed titanium case 6 of the device is heated, which adsorbs the molecules that form over time inside the sealed titanium case 6. This ensures that the design of the X-ray radiation generator is of high vacuum, which is one of the main conditions for correct operation device and determines the duration of its operation.

Examples of specific use:

To carry out the operation of the X-ray generator, a pyroelectric crystal 4 of lithium tantalate (LiTaO3) of the following sizes was used: diameter - 20 mm, height - 10 mm. Peltier element 2 of size (25 × 25) mm2 with a power output of 15 watts. The heat conduit 3, located between the pyroelectric crystal 4 and the Peltier element 2, was a 1.5 mm thick copper plate. And the heat conduit 1 attached to the Peltier element 2 was made of copper in the form of a plate 120 mm thick. A radiation intensity of the order of 106 counts / s to the full solid angle was obtained, which was recorded by the detector when x-rays passed through the beryllium output window of the generated radiation 5. All the structural elements were under a sealed titanium case 6 with a thickness of 2 mm, and the thickness of the highly developed inner surface 7 was 0.01 mm To determine the operational efficiency of the proposed utility model, tests were conducted to determine changes in the radiation intensity during operation of the described device. Tests showed that during continuous operation for 400 hours of continuous operation, the drop in the intensity of the generated radiation was no more than 2%, while the vacuum level did not change.

The X-ray generator will find application in radiography and fluoroscopy, X-ray flaw detection, X-ray diffraction and X-ray fluorescence analyzes. The proposed technical solution will extend the life of devices of this kind, and in case of leakage, which can lead to temporary abnormal leakage, the highly developed inner surface of the titanium case adsorbs molecules and restores the necessary pressure for normal operation of the device.

Claims (1)

An x-ray generator containing a pyroelectric crystal, a Peltier element, heat conduits, a beryllium output window of the generated radiation, a sealed housing, characterized in that the housing is made of titanium and has a highly developed inner surface.

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