KR101742571B1 - X-ray tube using pulse input - Google Patents

Abstract

The present invention relates to an X-ray generator capable of enhancing the intensity of an electron beam impinging on a target, and capable of using a pulse input. The X-ray generator includes an electron generating portion formed with a cathode electrode to emit an electron beam, And an electric field forming unit arranged on the path of the electron beam and arranged alternately in the longitudinal direction to accumulate electrons by the first electric field formation and discharge the electrons to the target in accordance with the formation of the second electric field, And provides an x-ray generator.

Description

[0001] X-RAY TUBE USING PULSE INPUT USING PULSE INPUT [0002]

The present invention relates to an X-ray generator, and more particularly, to an X-ray generator capable of enhancing the intensity of an electron beam impinging on a target, and capable of using a pulse input.

An X-ray tube is a device used as a source of X-rays for equipment that inspects objects in a non-contact or non-destructive manner. It is a device that generates X-rays by colliding electrons with a target.

Open No. 3-110753 discloses an X-ray tube, more specifically a closed-type X-ray generator, in which a tube formed by processing an insulating material such as a glass material into a substantially cylindrical shape is coupled to a lower body, A target support for supporting a target is fixed, and an electron gun is housed in the main body.

The electrons emitted from the electron gun collide with the target to generate X-rays, and X-rays are emitted to the outside of the X-ray tube.

1 is a view showing an X-ray tube of the prior art.

The structure of a conventional X-ray tube will be described with reference to FIG. 1. As shown in FIG. 1, the tube 11 is made of a glass material, and vacuum is maintained in order to transfer electrons and accurately radiate x-rays.

The tube 11 is provided with a cathode portion 12 through which a high voltage applied from the outside is inputted to discharge electrons and a pair of filaments 13 are provided in the cathode portion 12. And includes an anode portion 14 and a target 15 connected to the cathode portion 12 and emitting X-rays in an arbitrary direction.

In some cases, the target 15 may have various structures such as colliding with electrons emitted from the cathode portion by being connected to the tip of a rotation axis which is rotatably and rotatably disposed in the tube 11 at a high speed.

In addition, the tube 11 is provided with a transmitting portion (not shown) through which X-rays can be transmitted and emitted to the outside.

The operation of the conventional X-ray tube configured as described above will be described. When a high-voltage power inputted from the outside is applied to the cathode portion 12, electrons are emitted from the cathode portion 12 to collide with the target 15, The surface of the target is made in such a way that an X-ray is generated while a minute blemish occurs.

The X-rays generated in this way are emitted to the outside through the transmission part provided in the tube 11 and can be inspected by detecting X-rays scattered or transmitted through the inside of the inspected object or the surface of the inspected object.

Electrons generated in this process can not be converged to one point due to the initial velocity and form an electron beam of a finite size. When the electron collides with the X-ray target, the diameter of the X-ray is large and resolution of the X-ray image is degraded. In order to solve this problem, an electron beam aperture is provided between the anode and the electron beam focusing optical system to filter the outline of the focused electron beam. At the same time, since the electron beam current is lost, the luminance of the x- The problem that the acquisition time of the image becomes long is caused.

For this purpose, attempts have been made to focus the electron beam. Cold field emission is a method of generating electrons by applying a strong electric field without heating the cathode. The quantum tunneling effect of the cathode material tunneling effect. Since the withdrawal of the electron beam in the cold field emission depends only on the electric field applied to the cathode, the initial velocity distribution is more uniform than the hot electron emission.

Meanwhile, unlike a conventional carbon nanotube electron beam source, the tip-type carbon nanotube cathode electrode is selectively deposited with a carbon nanotube on the tip of a sharp needle-shaped metal tip. The tip of the carbon nanotube is selectively deposited according to the degree of etching of the metal tip. The diameter of the tip can be reduced from several micrometers to tens of nanometers. Since the electron beam is extracted from the carbon nanotube installed at the tip end, the electron beam can be extracted with a uniform initial velocity while the size of the electron generating portion is small, so that an electron beam focusing point smaller than that of the thermionic emission source can be achieved.

However, proper control of the input voltage is a very important factor for the application of these methods. When the electron beam current is small, it is difficult to acquire the image due to the decrease of the luminance of the X-ray.

The generation of high power X-rays, control of electron beam and control of input voltage are highly related to each other, which is a limitation in the design and operation of the equipment.

Accordingly, it is an object of the present invention to provide an X-ray generator capable of improving the current of an electron beam to generate a high-output X-ray while being able to cope with pulse input.

The present invention relates to a plasma display panel comprising an electron generating portion formed with a cathode electrode and emitting an electron beam, a target including an anode electrode generating an X-ray by collision of the electron beam, and a target disposed on a path of the electron beam, And an electric field forming unit arranged to accumulate electrons by the formation of the first electric field and to discharge electrons to the target according to the formation of the second electric field. Therefore, the intensity of the electron beam is increased and the focusing efficiency is improved by accumulation and emission of electrons.

The control unit may include an input unit for inputting a control voltage to the electron generating unit, an electric field applying unit for forming a first electric field in the electric field generating unit, and a field converting unit for forming a second electric field in the electric field generating unit have.

It is preferable that the input unit applies a pulse voltage as a control voltage to the electron generating unit.

According to the present invention, the strength of the electron beam in a limited structure and space is increased as a simple structure, which leads to an improvement in the efficiency of X-ray generation.

Since the focusing of the electron beam and the accumulation of electrons can be performed by the electric field generating part, the conventional coil can be omitted, the structural simplicity can be improved, and the pulse input can be controlled. Thus, There is a possible effect.

1 is a view showing an X-ray tube of the prior art.
2 is a conceptual diagram showing an X-ray generator using a pulse input according to the present invention.
3 is a block diagram for explaining a control system in an X-ray generator using a pulse input according to the present invention.
4 is a flowchart illustrating an X-ray generating method using the pulse input of the present invention.

Hereinafter, an X-ray generator using a pulse input according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the following description, when a part is referred to as being 'connected' to another part, it includes not only a direct connection but also a case where another part or device is connected in between. In addition, when a part is referred to as including an element, it is to be understood that the element may include other elements, not the exclusion of any other element, unless specifically stated otherwise.

The present invention basically comprises an electron generating unit in which a cathode electrode is formed to emit an electron beam, a target which generates x-rays by collision of the electron beam and which includes an anode electrode, And an electric field forming unit arranged alternately in the longitudinal direction and accumulating electrons by the formation of the first electric field and discharging electrons to the target according to the formation of the second electric field.

In the present invention, electrons emitted from the electron generating portion collide with a target fixed to a target support received in a tube to form an X-ray tube that emits an X-ray tube. The X-ray tube has a substantially vacuum state and a high- type tubes as well as open type tubes.

In the description of the present invention, the longitudinal direction is understood to mean the direction of the electron beam path from the electron generating portion to the target.

2 is a conceptual diagram showing an X-ray generator using a pulse input according to the present invention.

An X-ray generator using a pulse input according to the present invention basically comprises an X-ray tube 100 having an electron generator 120 and a target 113.

The electron generating part 120 includes a cathode and is formed by coating barium oxide (BaO) on a porous metal such as tungsten. The target 113 is made of a carbon material, and a coating for generating x-rays such as tungsten is formed on the upper layer.

When electrons generated from the electron gun collide with an anode or a target 113 including the anode, an X-ray is output through the output unit 114. [

In constructing such an electron gun, a gate electrode, a cathode, a cathode, and the like may be formed, and various known elements may be applied, so that a detailed description thereof will be omitted.

The electron generating part 120 is fixedly arranged on the inner side of the predetermined housing or the tube so that a high output voltage can be applied to the electron generating part 120 through a terminal part (not shown) on one side thereof, A target 113 that can collide with the electron beam is disposed.

An output unit (not shown) is formed at an arrangement position of the target 113, and the generated X-ray is radiated to the outside.

In the present invention, the electric field forming portion 300 is arranged on the path of the electron beam formed in the longitudinal direction so that the electron beam passes through the electric field there.

The electric field forming unit 300 is configured such that the electrodes disposed opposite to each other with the path of the electron beam therebetween are alternately arranged with different polarities in the longitudinal direction.

Although shown in the illustrated embodiment as being arranged in two sets, it should be understood that the number may be plural, and the number is optional.

The electric field generating unit 300 may be divided into a first electrode adjacent to the electron generating unit 120 and a second electrode adjacent to the target 113. As shown in FIG. In the case of the first electrode, electrons are charged to the positive electrode (+) so as to converge the electron beam from the electron generating unit 120, and in the case of the second electrode, the electron beam is controlled not to collide with the target 113, (-) so as to accumulate in the negative electrode (-). However, it is needless to say that the above polarity can be changed according to the number of the arranged electrodes or the effect of the electric field to be converted.

In a state where the first electric field is applied by the basic electric field forming part 300, the electrons are accumulated while the electron beams are focused. When a predetermined time has elapsed, the second electric field And the electron beam can be emitted to the target 113 side at a time.

Note that the second electric field does not mean that the polarity of all the electrodes constituting the electric field generating unit 300 is replaced with the opposite polarity.

In this way, when electrons are accumulated and discharged, there is a possibility that the structure of the coil for electron focusing of the conventional nose can be omitted, and the strength of the X-ray can be ensured even at a relatively low or high input voltage.

3 is a block diagram for explaining a control system in an X-ray generator using a pulse input according to the present invention.

The control unit 700 may function to input a control voltage to the electron generating unit 120 and to form an electric field, and the control unit 700 may include or be connected to a high voltage generator.

The control unit 700 includes an input unit 710 for inputting a control voltage to the electron generating unit 120, an electric field applying unit 720 for accumulating electrons to form a first electric field in the electric field generating unit 300, And an electric field converting unit 730 for forming a second electric field in the electric field forming unit 300 and discharging the electron beam to the target 113. [

As described above, the input unit 710 functions to generate an electron beam by inputting a voltage generated from the high voltage generating unit to the cathode. In the present invention, since an electric field is formed in the path of the electron beam to accumulate electrons, It is possible to input pulses instead of continuous waves.

In order to input the pulse voltage, the equipment constituting the X-ray output device is expensive and it is difficult to control the conventional electron gun. However, in the X-ray generator according to the present invention, It should be noted that this has advantages. This can lead to reduction of the load even in the operation of the detector.

The electric field applying unit 720 and the electric field converting unit 730 interact with each other to perform a function of maintaining or changing a predetermined charged state of the electrodes of the electric field forming unit 300. At this time, the electric field applying unit 720 and the electric field converting unit 730 may be provided with a control current input to the respective electrodes so as to maintain a charged state.

The electric field converter 730 temporarily converts the first electric field to the second electric field in response to the accumulation of electrons, for example, the satisfaction of the set time or the change in the charge amount, Release.

4 is a flowchart illustrating an X-ray generating method using the pulse input of the present invention.

Here, the case where the input unit 710 basically uses the pulse input as the control voltage is described as a reference, but in the case of the continuous wave, the remaining configuration may be applied.

When the pulse input is applied (S110) by the control unit 700, the electron generating unit 120 starts emission of the electron beam (S120).

When the electron beam is formed in the longitudinal direction within the X-ray generator, or before the electron beam is formed in the longitudinal direction, the electric field applying unit 720 of the controller 700 forms a first electric field in each electrode under predetermined conditions (S210 ).

The first electric field thus formed enables focusing and accumulation of electrons while suppressing the progress of the electron beam. Accordingly, when electrons accumulate, the electric field transforming unit 730 forms a second electric field (S220) to change the charging relationship to emit the electron beam at a time, and when the electron beam collides with the target 113, . In the process of forming the second electric field (S220), the electric field generating unit 300 may perform a focusing function of the electron beam.

In order to focus the electron beams and accumulate electrons, each of the electrodes constituting the electric field generating unit 300 preferably has a ring shape in which a through hole or a penetrating material through which an electron beam can penetrate is formed on the center side. However, no.

With the X-ray generator using the pulse input of the present invention as described above, the intensity of the electron beam in a limited structure and space is increased as a simple structure, which leads to an improvement in efficiency of X-ray generation.

Since the focusing of the electron beam and the accumulation of electrons can be performed by the electric field generating part, the conventional coil can be omitted, the structural simplicity can be improved, and the pulse input can be controlled. Thus, There is a possible advantage.

In the foregoing, the present invention has been described in detail based on the embodiments and the accompanying drawings. However, the scope of the present invention is not limited by the above embodiments and drawings, and the scope of the present invention will be limited only by the content of the following claims.

113 ... target 120 ... electron generator
300 ... electric field type part 700 ... control part
710 ... input unit 720 ... electric field applying unit
730 ... electric field converting section

Claims (3)

An electron generating portion formed with a cathode electrode and emitting an electron beam;
A target for generating X-rays by collision of the electron beam and including an anode electrode; And
And an electric field generating part composed of a first electrode adjacent to the electron generating part and a second electrode adjacent to the target on the path of the electron beam and accumulating electrons by the first electric field formation and discharging the electrons to the target according to the formation of the second electric field In addition,
The field-
Wherein the first electrode is charged to the anode and the second electrode is charged to the cathode so as to concentrate the electron beam and accumulate the electrons.
The method according to claim 1,
And a control unit having an input unit for inputting a control voltage to the electron generating unit, an electric field applying unit for forming a first electric field in the electric field generating unit, and an electric field converting unit for forming a second electric field in the electric field generating unit, Device.
3. The method of claim 2,
Wherein the input unit comprises:
And applies a pulse voltage to the electron generating portion as a control voltage.

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