RU176453U1 - X-ray generator during deformation of a piezoelectric in vacuum - Google Patents

Abstract

The utility model relates to the field of X-ray technology and can be used to generate X-ray radiation used in radiography and fluoroscopy, radiotherapy, X-ray flaw detection, X-ray diffraction and X-ray fluorescence analyzes. The device contains two piezoelectric elements connected to each other through a cathode in the form of a high voltage electrode, an anode made in the form of two grounded electrodes, and two actuators that are grounded and not isolated from the high voltage electrode, in addition, the piezoelectric elements, high voltage and grounded electrodes are in vacuum, and actuators are located outside the vacuum. The proposed device will find application in x-ray therapy - a section of radiation therapy, covering the theory and practice of the therapeutic use of x-rays generated at a voltage of 20-60 kV. Also, the proposed device can be used for x-ray fluorescence analysis of various structures, calibration of various x-ray devices. The independence of the device from electrical power supplies makes it a profitable tool for use in field and extreme conditions. Also, the proposed device can be used in x-ray inspection - the identification of defects in products using x-rays.

Description

X-ray generator during deformation of a piezoelectric in vacuum.

The utility model relates to the field of X-ray technology and can be used to generate X-ray radiation used in radiography and fluoroscopy, radiotherapy, X-ray flaw detection, X-ray diffraction and X-ray fluorescence analyzes.

The most common and traditional way to generate x-rays is to use x-ray tubes that apply high voltage to a cathode that emits electrons. Electrons, in turn, under the influence of the potential difference between the cathode and the anode are accelerated to the anode and when braking in it produce x-ray radiation. One of the first such devices, the operation of which is based on this principle, is the "X-ray tube" described in patent US 1946312 A (publ. 02/06/1934). And in a later work with the same name “X-ray tube”, described in patent US 3649861 A (publ. March 14, 1972), it is proposed to create such a design that allows you to implement two focal spots in one x-ray tube.

Subsequently, the X-ray generation scheme was repeatedly modernized, but the basic principle of operation was preserved. For example, one of the latest known inventions, “X-ray source, method for generating x-ray radiation, as well as the use of an x-ray source emitting monochromatic x-ray radiation”, described in patent RU 2608189 (publ. 01/17/2017), involves the use of airgel as targets for the generation of monochromatic x-ray radiation.

The common disadvantages of traditional devices are high energy costs, associated primarily with the need to use a high-voltage power supply unit and warm the cathode to high temperatures.

Another known method for generating x-rays is based on the application of the pyroelectric effect in pyroelectric crystals. This effect consists in the fact that when the temperature of the pyroelectric crystal changes, a high potential is generated on the surface of the crystal, the sign of which depends on the direction of the temperature change and is used to accelerate the electrons to the target or to the crystal and further generate x-rays during electron braking. Based on this principle of operation, a device called the “X-ray tube” is described, which is described in US Pat. No. 3,807,748 A (publ. 08/10/1974).

The disadvantage of this method, based on the pyroelectric effect, is the instability of the process of generating radiation in pyroelectric crystals with a change in their temperature.

Devices are known in which it is proposed to use a high voltage source operating on a piezoelectric effect to generate x-ray radiation. One of such devices, called "Method and system for a high-voltage piezoelectric source of x-ray radiation", is described in patent US 9287080 B2 (publ. March 15, 2016) and is the closest to the proposed device. Such a technical solution is intended to generate x-ray radiation and consists of: an x-ray vacuum chamber, in which the mechanism of this device is located, a piezoelectric cylinder located inside the cylindrical chamber, which is subjected to pulsed or compressive vibration. As a result of this action, the piezoelectric material induces a charge proportional to the voltage, the input vibrational force, or the pulse that accumulates at the cathode. Electrons are accelerated from the cathode and produce x-rays in the anode inside cylindrical ceramics. In this case, the high-voltage end of the cylindrical ceramic is subjected to force from the actuator through the insulator.

The disadvantage of this device is the mandatory use of a high voltage power source and insulation materials between structural elements.

The task to which the proposed technical solution is directed is to create a device that allows to generate x-ray radiation by deformation of piezoelectric elements in a vacuum.

The problem is solved using the proposed device, the x-ray generator during deformation of the piezoelectric in vacuum, containing the piezoelectric element, cathode, anode and actuator, and the device contains two piezoelectric elements connected to each other through the cathode in the form of a high voltage electrode, the anode made in the form of two grounded electrodes and two actuators that are grounded and not isolated from the high-voltage electrode, in addition, piezoelectric elements, high-voltage and grounded electrodes are in vacuum, and s are arranged outside the vacuum.

The proposed device differs from the prototype in that the piezoelectric elements, the high-voltage and grounded electrodes are in vacuum, and the actuators are located outside the vacuum and are grounded, and insulating material between the high-voltage electrode and actuators is not required, which reduces the capacitance between the high-voltage electrode and ground, and increases the voltage , the energy of electrons, the acceleration of which is carried out outside the piezoelectric elements, and not inside, as in the prototype and, as a result, increases the energy of the generated x-ray th radiation.

The first advantage of the proposed utility model is the absence of any electromagnetic and thermal effects, as in x-ray tubes with a thermal cathode or pyroelectric sources, on the electric field source (piezoelectric elements), which allows the generation of x-ray radiation at significantly lower energy costs. The second advantage is the absence of an external high-voltage power supply, because high voltage is generated inside a vacuum metal chamber. The third advantage is high voltage safety, because in the event of a vacuum breaking, the charge from the high voltage electrode flows to the ground and the high voltage disappears. A fourth advantage is the ability to generate x-rays both when the force applied to the piezoelectric elements is increased (in this case, for example, a high-voltage electrode serves as an anode), and when the force is reduced (in this case, for example, a grounded electrode serves as an anode). The fifth advantage is the absence of an insulator between the high-voltage electrode and the actuator, which reduces the capacitance and increases the energy of the generated x-ray radiation.

The technical result of the proposed device is to increase the generation of x-ray radiation due to the use of a high-voltage electrode between the piezoelectric elements to collect the induced charge and the deformation mechanism of the piezoelectric elements in the vacuum. This mechanism consists in a controlled effect on the piezoelectric elements only by external force and does not provide any electromagnetic and thermal effects.

The utility model is illustrated in the drawing.

FIG. 1 is a functional diagram of a device.

The device consists of two piezoelectric elements 1, a high voltage electrode 2, two grounded electrodes 3 and two actuators 4.

Piezoelectric elements (ferroelectric, piezoelectric crystals or piezoelectric ceramics) 1 are made in the form of a cylinder or parallelepiped and are interconnected via a high-voltage electrode 2 made of a conductive material. High voltage electrode 2 is designed to generate high voltage. Grounded electrodes 3 are thin metal plates and are grounded through a wire connected to a common ground. From the surface of the grounded electrodes 3 is the acceleration of electrons and the generation of x-rays. The deformation mechanism is implemented by directly affecting the piezoelectric elements 1. Actuators 4 are metal cylinders and provide a connection between the deformation mechanism located outside the vacuum chamber and the piezoelectric elements 1, which are located inside the vacuum chamber. The design of the deformation mechanism depends on the method of the particular application, and the force of influence is controlled. It is possible to implement the deformation mechanism using an electrodeformation machine or using additional piezoelectric motors.

The device operates at a residual gas pressure in the vacuum chamber of 0.001 - 1000 mTorr. Piezoelectric elements 1, a high voltage electrode 2, and two grounded electrodes 3 are placed in a vacuum chamber, and two actuators 4 are located outside the vacuum chamber. When mechanical force is applied to the actuators 4, implementing the deformation mechanism, the piezoelectric elements 1 generate a charge, while the piezoelectric elements 1 must be oriented so that the potential in the center is negative, and at the opposite ends of the piezoelectric elements 1 the potential is positive. The negative potential at the high-voltage electrodes 2 allows accelerating the electrons in the direction from the high-voltage electrodes 2 to the grounded electrodes 3. Accelerated electrons entering the walls of the vacuum chamber or to a special target generate x-ray radiation of elements that are part of the wall of the vacuum chamber or special target. The strain is determined by the voltage equal to the ratio of the applied force to the area of the piezoelectric elements 1. When the load applied to the actuators 4 is removed, a positive potential is generated on the high-voltage electrode 2, as a result, the electrons are accelerated to the high-voltage electrode 2 and produce x-ray radiation when braking in a grounded electrode 3. With an increase in the force acting on the piezoelectric elements 1, the high-voltage electrode acts as the cathode, and the grounded electrode acts as the anode, and when decreasing, we apply Of high strength, the high-voltage electrode acts as the anode, and the grounded electrode acts as the cathode.

As an example of the operation of the proposed device, we used piezoelectric elements 1 made of lead zirconate-titanate-borate (CTBS-3m) in the form of cylinders of size 8 mm × 15 mm. High-voltage electrode 2 was made of copper (Cu) with a size of 9 mm × 5 mm. The grounded electrode 3 is a thin plate in the form of a disk of zinc (Zn) with a size of 50 mm × 1 mm. Actuators 4 with a size of 20 mm × 200 mm are made in the form of cylinders made of aluminum alloy D16T. When the piezoelectric elements 1 were subjected to a mechanical stress of 100 MPa, X-ray radiation was obtained with an energy of up to 50 keV, an integrated intensity of up to 105 photons per second for 40 seconds.

The proposed device will find application in x-ray therapy - a section of radiation therapy, covering the theory and practice of the therapeutic use of x-rays generated at a voltage of 20-60 kV. Also, the proposed device can be used for x-ray fluorescence analysis of various structures, calibration of various x-ray devices. The independence of the device from electrical power supplies makes it a profitable tool for use in field and extreme conditions. Also, the proposed device can be used in x-ray inspection - the identification of defects in products using x-rays. Using this device, it is possible to obtain high voltage, which will accelerate charged particles in a given direction, which will find application in scientific research.

Claims (1)

1. The x-ray generator during the deformation of a piezoelectric in vacuum, containing a piezoelectric element, cathode, anode and actuator, characterized in that the device contains two piezoelectric elements connected to each other through a cathode in the form of a high-voltage electrode, an anode made in the form of two grounded electrodes, and two actuators that are grounded and not isolated from the high voltage electrode, in addition, piezoelectric elements, high voltage and grounded electrodes are in vacuum, and actuators are located outside of vacuum.

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