X-ray inspection apparatus and method for determining target consumption of X-ray tube thereof

Abstract

The present invention provides an X-ray inspection apparatus and a method for determining the consumption of a target of an X-ray tube thereof, which can accurately estimate the consumption of a target even when the X-ray dose changes over time. The consumption determination unit (34) includes: a measuring unit (35) for detecting the X-ray dose during a predetermined period by detecting X-rays emitted from an X-ray tube (1) using an X-ray detector (42), and measuring a maximum value Imax and a minimum value Imin of the X-ray dose during the period; a calculation unit (36) for calculating a variation rate of the X-ray dose using the maximum value Imax and the minimum value Imin of the X-ray dose measured by the measuring unit (35); a determining unit (37) for determining that the target (13) of the X-ray tube (1) is being consumed when the variation rate of the X-ray dose calculated by the calculation unit (36) exceeds a preset threshold; and a warning display unit (38) for displaying a warning when the determining unit (37) determines that the target (13) of the X-ray tube (1) is being consumed.

Description

Technical Field

[0001] The present invention relates to an X-ray inspection apparatus and a method for determining the degree of consumption of a target of an X-ray tube in the X-ray inspection apparatus. Background Art

[0002] One type of X-ray inspection apparatus is an X-ray inspection apparatus that uses X-rays to inspect the internal structure of a three-dimensional inspection object without destroying it. Such an X-ray inspection apparatus includes an X-ray imaging system having an X-ray tube for emitting X-rays toward the inspection object, an X-ray detector such as a flat panel detector or an image intensifier (II) for detecting X-rays emitted from the X-ray tube and transmitted through the inspection object, a platform disposed between the X-ray tube and the X-ray detector, on whose upper surface the inspection object is placed, and a moving mechanism for moving the platform relative to the X-ray imaging system.

[0003] The X-ray tube used in such an X-ray inspection apparatus includes a filament (cathode) to which a high voltage is applied and a target (anode). When the high voltage is applied, an electron beam including thermal electrons emitted from the filament collides with the target to generate X-rays.

[0004] In this type of X-ray tube, the target is consumed by repeated collisions with the electron beam. Specifically, the target is gradually consumed over the time it takes to generate X-rays. Furthermore, it is known that as the target consumes, the intensity (X-ray dose) of X-rays generated at a constant tube voltage and current decreases (see Patent Document 1). Therefore, by measuring the intensity of X-rays generated at a constant tube voltage and current, the degree of target consumption can be estimated.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] International Publication No. WO2003 / 092336 Summary of the Invention

[0008] [Problems to be solved by the invention]

[0009] However, in reality, the fluctuation of the amount of X-rays emitted from the X-ray tube is not so simple. Figure 6 This is a graph showing the temporal change in the X-ray dose of X-rays emitted from an X-ray tube.

[0010] Figure 6The graph shown in Figure 1 shows X-ray dose measurement results obtained by detecting X-rays emitted from an X-ray tube with a target consumed using an X-ray detector over a 30-minute period with a sampling period of 1 second. The horizontal axis of the graph represents time (minutes), and the vertical axis represents the X-ray dose per minute (R / min).

[0011] As shown in this figure, the amount of X-rays emitted from the X-ray tube increases and decreases over time. For example, in the measurement results shown in this graph, the X-ray amount reaches a maximum value Imax immediately after the X-ray tube is driven, and reaches a minimum value Imin after about 10 minutes. Then, the X-ray amount repeats slight increases and decreases before and after the minimum value Imin. It is speculated that the reason for this is that the collision position (focal position) of the electron beam in the target changes during the measurement of the radiation amount due to the thermal expansion of the target or the component supporting the target accompanying the collision of the electron beam. That is, the X-ray amount decreases when the electron beam collides with a degraded area in the target, and increases when the electron beam collides with an undegraded area in the target. Therefore, when the X-ray amount is measured at the time when the X-ray amount increases or decreases to determine the consumption level of the target, the problem of not reflecting the correct consumption level arises.

[0012] The present invention is made to solve the above-mentioned problems, and its purpose is to provide an X-ray inspection apparatus and a method for determining the target consumption of an X-ray tube in the X-ray inspection apparatus, which can accurately estimate the target consumption even when the X-ray dose changes over time.

[0013] [Technical means to solve the problem]

[0014] The invention described in technical solution 1 is an X-ray inspection device, which is an X-ray inspection device including an X-ray tube that generates X-rays by causing an electron beam to collide with a target, and an X-ray detector that detects X-rays emitted from the X-ray tube and transmitted through an inspection object, and is characterized by including: a measuring unit that detects the X-ray dose during a predetermined period by detecting X-rays emitted from the X-ray tube during the period using the X-ray detector, and measures a maximum value Imax and a minimum value Imin of the X-ray dose during the period; a calculation unit that calculates a rate of change of the X-ray dose using the maximum value Imax and the minimum value Imin of the X-ray dose measured by the measuring unit; and a rate of change display unit that displays the rate of change of the X-ray dose calculated by the calculation unit.

[0015] The invention described in technical solution 2 is an X-ray inspection device, which is an X-ray inspection device including an X-ray tube that generates X-rays by causing an electron beam to collide with a target, and an X-ray detector that detects X-rays emitted from the X-ray tube and transmitted through an inspection object, and is characterized in that it includes: a measuring unit that detects the X-ray dose during a specified period by detecting X-rays emitted from the X-ray tube using the X-ray detector during the period, and measures a maximum value Imax and a minimum value Imin of the X-ray dose during the period; a calculation unit that calculates a variation rate of the X-ray dose using the maximum value Imax and the minimum value Imin of the X-ray dose measured by the measuring unit; and a determination unit that determines that the target is being consumed when the variation rate of the X-ray dose calculated by the calculation unit exceeds a preset threshold value.

[0016] The invention according to claim 3 is the X-ray inspection apparatus according to claim 1 or 2, wherein the calculation unit calculates the rate of change of the X-rays based on [(Imax-Imin) / Imax].

[0017] The invention according to claim 4 is the X-ray inspection apparatus according to claim 1 or 2, wherein the calculation unit calculates the rate of change of the X-rays based on [Imin / Imax].

[0018] The invention described in Technical Solution 5 is that in the X-ray inspection device described in any one of Technical Solutions 1 to Technical Solution 4, the measuring unit measures the maximum value Imax of the X-ray amount and the minimum value Imin of the X-ray amount as the average values ​​of the detection values ​​detected in a fixed area in the X-ray detector.

[0019] The invention described in Technical Solution 6 is that in the X-ray inspection device described in any one of Technical Solutions 1 to Technical Solution 4, the measuring unit measures the maximum value Imax of the X-ray amount and the minimum value Imin of the X-ray amount as the peak values ​​of the distribution of the detection values ​​detected in a fixed area in the X-ray detector.

[0020] The invention described in technical solution 7 is a method for determining the degree of consumption of a target of an X-ray tube in an X-ray inspection device, which is a method for determining the degree of consumption of a target of an X-ray tube in an X-ray inspection device, comprising an X-ray tube for generating X-rays by causing an electron beam to collide with a target, and an X-ray detector for detecting X-rays emitted from the X-ray tube and passing through an inspection object. The method is characterized in that the X-ray dose during a prescribed period is detected by detecting X-rays emitted from the X-ray tube using the X-ray detector, and a maximum value Imax and a minimum value Imin of the X-ray dose during the period are measured, a variation rate of the X-ray dose is calculated using the maximum value Imax and the minimum value Imin of the X-ray dose, and the degree of consumption of the target is determined based on the variation rate of the X-ray dose.

[0021] [Effects of the Invention]

[0022] According to the invention described in Technical Solutions 1 to 7, the maximum value Imax of the X-ray amount and the minimum value Imin of the X-ray amount within a fixed period are used to calculate the rate of change of the X-ray amount, and the consumption of the target is determined based on this calculated value. Therefore, when a change in the X-ray amount over time occurs, the consumption degree of the target can also be accurately estimated.

[0023] According to the invention described in Technical Solutions 5 and 6, even when there are abnormal values ​​due to pixel defects in the X-ray detector, the target consumption can be accurately estimated by using the average value of the detection values ​​detected in a fixed area or the peak value of the brightness distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram showing the X-ray inspection apparatus of the present invention together with its main control system.

[0025] Figure 2 It is a schematic diagram of the X-ray generation unit 41 including the X-ray tube 1 .

[0026] Figure 3 This is a graph showing the relationship between the X-ray dose of X-rays emitted from the X-ray tube 1 and the brightness value of each pixel when the X-rays are detected by the X-ray detector 42 .

[0027] Figure 4 This is a graph showing the relationship between the value [(Imax−Imin) / Imax] calculated from the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose and the driving time of the X-ray tube 1 .

[0028] Figure 5This is a graph showing the relationship between the value of [Imin / Imax] calculated from the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose and the driving time of the X-ray tube 1 .

[0029] Figure 6 This is a graph showing the temporal change in the X-ray dose of X-rays emitted from the X-ray tube.

[0030] [Explanation of Symbols]

[0031] 1: X-ray tube

[0032] 2: High voltage generating unit

[0033] 11: Filament

[0034] 13: Target

[0035] 30: Control Department

[0036] 31: Image processing unit

[0037] 32: Mobile Control Department

[0038] 33: X-ray tube control unit

[0039] 34: Consumption Determination Unit

[0040] 35: Measurement Department

[0041] 36: Operation unit

[0042] 37: Judgment Department

[0043] 38: Warning display unit

[0044] 39: Change rate display unit

[0045] 40: Platform

[0046] 41: X-ray generating unit

[0047] 42: X-ray detector

[0048] 43: Platform moving mechanism

[0049] 44: Display unit

[0050] 45: Operation Department

[0051] 100: Shell

[0052] W: workpiece. DETAILED DESCRIPTION

[0053] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1This is a schematic diagram showing the X-ray inspection apparatus of the present invention together with its main control system.

[0054] The X-ray inspection apparatus of the present invention includes an X-ray generator 41 including an X-ray tube 1 (described later) for emitting X-rays toward a workpiece W serving as an inspection object; an X-ray detector 42, such as a flat panel detector or image intensifier (II), for detecting X-rays emitted from the X-ray generator 41 and transmitted through the workpiece W; and a platform 40 for mounting the workpiece W, disposed between the X-ray generator 41 and the X-ray detector 42. The platform 40 is movable in two mutually orthogonal directions within a horizontal plane by a platform movement mechanism 43 including a motor (not shown). The X-ray generator 41, X-ray detector 42, platform 40, and platform movement mechanism 43 are disposed within a housing 100 that includes an X-ray shielding member.

[0055] Figure 2 It is a schematic diagram of the X-ray generation unit 41 including the X-ray tube 1 .

[0056] This X-ray generator 41 has a structure in which an X-ray tube 1 and a high-voltage generator 2 are housed within a chamber comprising a housing 3 and a cover 4. The chamber comprising the housing 3 and the cover 4 is filled with insulating oil. The insulation method is not limited to using insulating oil; insulating solids or gases may also be used.

[0057] The X-ray tube 1 includes a glass tube 15 and a plurality of terminals 23 arranged across the interior and exterior of the glass tube 15. Also arranged within the glass tube 15 are a filament 11, a heater 12, and a target 13. The filament 11 radiates an electron beam toward the target 13. The electron beam emitted from the filament 11 collides with the target 13, generating X-rays. These X-rays are emitted toward the exterior of the X-ray tube 1. The heater 12, also known as a getter, adsorbs gas molecules within the glass tube 15.

[0058] The target 13 is connected to a terminal 21 in the high-voltage generator 2 via a cable 25, and is supplied with a high voltage for accelerating the electron beam from the high-voltage generator 2. The cable 25 is supported by a support member 26 disposed at the top of the housing 3. Furthermore, a terminal 23 in the X-ray tube 1, which is connected to the filament 11 and the hot filament 12, is connected to a terminal 22 in the high-voltage generator 2 via a cable 24. A filament current is supplied to the filament 11 from the high-voltage generator 2 via the terminal 22, the cable 24, and the terminal 23. Furthermore, a hot filament current is supplied to the hot filament 12 from the high-voltage generator 2 via the terminal 22, the cable 24, and the terminal 23.

[0059] In addition, Figure 2In the present invention, an X-ray tube 1 having a sealed structure is used, in which a filament 11, a target 13, etc. are arranged in a glass tube body 15 as a sealed container. However, the present invention can also be applied to an X-ray inspection apparatus including an open X-ray tube in which the filament 11, the target 13, etc. can be replaced as a single unit.

[0060] Refer again Figure 1 The X-ray inspection apparatus of the present invention includes a control unit 30. This control unit 30 includes a central processing unit (CPU) that performs logical operations, a read-only memory (ROM) that stores operating programs required for apparatus control, and a random access memory (RAM) that temporarily stores data during control. The control unit 30 controls the entire apparatus. The control unit 30 comprises a computer with software installed. The functions of each component of the control unit 30 are implemented by executing the software installed on the computer.

[0061] The control unit 30 is connected to a display unit 44, such as a liquid crystal display panel, which displays an X-ray image detected by the X-ray detector 42 or a rate of change in the X-ray dose (described later), and an operation unit 45, such as a mouse or keyboard, for performing various operations. Furthermore, the control unit 30 includes, as functional components, an image processing unit 31 for processing the X-ray image detected by the X-ray detector 42 and displaying it on the display 44; a movement control unit 32 for controlling the stage movement mechanism 43; an X-ray tube control unit 33 for controlling the lighting of the X-ray tube 1; and a consumption determination unit 34 for determining the consumption of the target 13 in the X-ray tube 1.

[0062] In addition, the consumption determination unit 34 includes: a measuring unit 35, which detects the X-ray dose during a predetermined period by detecting X-rays emitted from the X-ray tube 1 using the X-ray detector 42 in a state where the workpiece W is not placed on the stage 40, and measures a maximum value Imax and a minimum value Imin of the X-ray dose during the period; a calculation unit 36, which calculates a variation rate of the X-ray dose using the maximum value Imax and the minimum value Imin of the X-ray dose measured by the measuring unit 35; a determination unit 37, which determines that the target 13 of the X-ray tube 1 is being consumed when the variation rate of the X-ray dose calculated by the calculation unit 36 ​​exceeds a preset threshold value; a warning display unit 38, which displays a warning when the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed; and a variation rate display unit 39, which displays the variation rate of the X-ray dose calculated by the calculation unit 36 ​​on the display 44.

[0063] In this type of X-ray inspection apparatus, as the X-ray tube 1 is used over time, the target 13 is worn out due to repeated collisions with the electron beam. Furthermore, the inventors of the present invention have recognized that as the target 13 is worn out, the fluctuation in the X-ray dose of X-rays emitted from the X-ray tube 1 increases. Specifically, the X-ray tube 1 was continuously emitted, and the X-ray dose was measured for 30 minutes every 1000 hours of continuous emission. The fluctuation in the X-ray dose over these 30 minutes was measured. The results confirmed that as the continuous emission time of the X-ray tube 1 increases and the target 13 is worn out, the fluctuation in the X-ray dose of X-rays emitted from the X-ray tube 1 increases.

[0064] Therefore, in the X-ray inspection apparatus, for example, the change in the X-ray dose is measured based on the maximum and minimum values ​​of the X-ray dose within a fixed period of about 30 minutes, and the rate of change of the X-ray dose is calculated to determine the degree of consumption of the target 13. When the rate of change exceeds a predetermined threshold, it is determined that the target 13 is being consumed to the extent that it needs to be replaced, and a warning display is displayed to urge the replacement of the X-ray tube 1 or the target 13.

[0065] Furthermore, in the X-ray inspection apparatus, the target 13's consumption level is determined during aging. Specifically, at the start of a day's operation or upon restart after a fixed period of non-use, a so-called aging process is performed. After applying a low tube voltage to the X-ray tube 1, the tube voltage is gradually increased. This melts foreign matter, such as protrusions on the high-voltage application portion, which are at the same potential as the target 13 and cause electric field concentration. This creates a smooth equipotential surface and improves high-voltage withstand characteristics. During this process, the target 13's consumption level is determined using the pixel values ​​of the X-ray image detected by the X-ray detector 42 at a specified tube voltage and tube current. However, the target 13's consumption level can also be determined at other times.

[0066] When determining the consumption level of the target 13, the measuring unit 35 of the consumption level determining unit 34 first detects the X-ray dose during a predetermined period by detecting X-rays emitted from the X-ray tube 1 using the X-ray detector 42, with the workpiece W not placed on the stage 40, i.e., with uniform X-rays emitted from the X-ray generator 41 toward the X-ray detector 42. The measuring unit 35 calculates the X-ray dose during that period based on the brightness value of each pixel, which indicates the intensity of the X-rays detected by the X-ray detector 42.

[0067] Figure 3 This is a graph showing the relationship between the X-ray dose of X-rays emitted from the X-ray tube 1 and the brightness value of each pixel when the X-rays are detected by the X-ray detector 42 .

[0068] This graph shows the relationship between the X-ray dose and brightness when the tube voltage applied to the X-ray tube 1 is set to, for example, 80 kV, 60 kV, and 40 kV, and the tube current is gradually increased. The vertical axis of the graph represents the X-ray dose (R / min), and the horizontal axis represents the brightness value (arbitrary units). As shown in the graph, the X-ray dose emitted by the X-ray tube 1 is proportional to the brightness value of each pixel when the X-rays are detected by the X-ray detector 42. Therefore, by detecting the X-rays emitted from the X-ray tube 1 using the X-ray detector 42, the X-ray dose can be calculated based on the brightness value measured by the X-ray detector 42.

[0069] Furthermore, when measuring the X-ray dose, the average value of the brightness detected in a fixed area of ​​the X-ray detector 42 is used. This ensures the accuracy of the measured value even when abnormal pixel values ​​are present due to defective pixels in the X-ray detector 42. Furthermore, the fixed area is preferably selected from an area near the center of the X-ray detection area of ​​the X-ray detector 42. However, the X-ray dose may be calculated based on the average value of other areas of the X-ray detector 42. Alternatively, the X-ray dose may be calculated based on the average value of all X-ray detection areas in the X-ray detector 42.

[0070] When measuring the X-ray dose, the maximum value Imax and the minimum value Imin of the X-ray dose may be measured as peak values ​​of the distribution of detection values ​​detected in a fixed area of ​​the X-ray detector 42, instead of using the average value of the brightness detection values ​​of the fixed area of ​​the X-ray detector 42. That is, the maximum value of the detection values ​​detected in the fixed area of ​​the X-ray detector 42 may be set as the maximum value Imax of the X-ray dose, and the minimum value may be set as the minimum value Imin of the X-ray dose.

[0071] By detecting the X-rays emitted from the X-ray tube 1 using the X-ray detector 42 for a period of, for example, 30 minutes, the X-ray dose can be obtained. Figure 6 . Based on the X-ray dose measured over time as described above, the measuring unit 35 measures the maximum value Imax and the minimum value Imin of the X-ray dose during the period. Furthermore, the computing unit 36 ​​computes the rate of change of the X-ray dose using the maximum value Imax and the minimum value Imin of the X-ray dose measured by the measuring unit 35.

[0072] The calculation result of the variation rate is displayed on the display unit 44 via the variation rate display unit 39. Thus, the operator can understand the variation rate of X-rays and predict the consumption of the target 13 of the X-ray tube 1 based on the variation rate of X-rays.

[0073] Figure 4 This is a graph showing the relationship between the value [(Imax−Imin) / Imax] calculated from the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose and the operating time of the X-ray tube 1 .

[0074] In this figure, the vertical axis represents the value of [(Imax - Imin) / Imax], and the horizontal axis represents the operating time (h). In this figure, the following configuration can be adopted: based on the fact that as the target 13 is worn out, the fluctuation in the X-ray dose emitted from the X-ray tube 1 increases, and when the value of [(Imax - Imin) / Imax] calculated by the calculation unit 36 ​​becomes greater than a certain value, it is determined that the target 13 has reached a level of wear that requires replacement of the X-ray tube 1.

[0075] That is, when the rate of change of the X-ray dose calculated from [(Imax-Imin) / Imax] exceeds a preset threshold value, the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed. Figure 4 In the graph shown in , when the value of [(Imax-Imin) / Imax] is greater than 0.12, the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed. In this case, when the driving time of the X-ray tube 1 has exceeded 8000 hours, the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed.

[0076] When the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed, the warning display unit 38 displays a warning on the display unit 44. Alternatively, the warning display may be performed by sound or light.

[0077] This allows notification of the consumption of the target 13 in advance, prompting replacement of the target 13 or the X-ray tube 1. Therefore, it is possible to prevent a situation in which an X-ray inspection cannot be performed due to the consumption of the target 13.

[0078] Another embodiment of calculating the rate of change of the X-ray dose using the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose will be described. Figure 5 This is a graph showing the relationship between the value of [Imin / Imax] calculated from the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose and the operating time of the X-ray tube 1 .

[0079] In this figure, the vertical axis represents the value of [Imin / Imax], and the horizontal axis represents the operating time (h). In this figure, the following configuration can be adopted: based on the fact that as the target 13 is worn out, the fluctuation in the X-ray dose emitted by the X-ray tube 1 increases, and when the value of [Imin / Imax] calculated by the calculation unit 36 ​​falls below a certain level, it is determined that the target 13 has reached a level of wear, requiring replacement of the X-ray tube 1.

[0080] That is, when the rate of change of the X-ray dose calculated based on [Imin / Imax] exceeds a preset threshold value downward, the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed. Figure 5 In the graph shown in , when the value of [Imin / Imax] is less than 0.85, the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed. In this case, when the driving time of the X-ray tube 1 has exceeded 8000 hours, the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed.

[0081] When the determination unit 37 determines that the target 13 of the X-ray tube 1 is being consumed, the warning display unit 38 displays a warning on the display unit 44. In this embodiment, the consumption of the target 13 can be notified in advance to urge replacement of the target 13 or the X-ray tube 1.

[0082] In addition, in the above-described embodiment, the present invention is described as being applied to an X-ray inspection apparatus that inspects the internal structure of an inspection object having a three-dimensional shape using X-rays without destroying the object, but the present invention can also be applied to other X-ray inspection apparatuses such as medical X-ray inspection apparatuses that obtain X-ray images of an inspected person.

Claims

1. An X-ray inspection device, characterized in that include: X-ray tubes, which produce X-rays by causing an electron beam to hit the same location on a target; an X-ray detector for detecting X-rays emitted from the X-ray tube and transmitted through the inspection object; a measuring unit that continuously detects X-rays emitted from the X-ray tube using the X-ray detector during a predetermined period to detect an X-ray dose during the period, and measures a maximum value Imax and a minimum value Imin of the X-ray dose during the period; as well as a calculation unit that calculates a rate of change of the X-ray dose detected continuously by the X-ray detector during the predetermined period, using the maximum value Imax and the minimum value Imin of the X-ray dose measured by the measuring unit; The rate of change of the X-ray dose calculated by the calculation unit is displayed as information indicating whether the target is being consumed. Alternatively, when the rate of change of the X-ray dose calculated by the calculation unit exceeds a preset threshold value, it is determined that the target is being consumed.

2. The X-ray inspection apparatus according to claim 1, wherein The calculation unit calculates the rate of change of the X-rays based on [(Imax−Imin) / Imax].

3. The X-ray inspection apparatus according to claim 1, wherein The calculation unit calculates the rate of change of the X-rays based on [Imin / Imax].

4. The X-ray inspection apparatus according to any one of claims 1 to 3, characterized in that The measuring unit measures the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose as average values ​​of detection values ​​detected in a fixed area of ​​the X-ray detector.

5. The X-ray inspection apparatus according to any one of claims 1 to 3, characterized in that The measuring unit measures the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose as peaks of a distribution of detection values ​​detected in a fixed area of ​​the X-ray detector.

6. A method for determining the degree of consumption of a target of an X-ray tube in an X-ray inspection apparatus, wherein the method comprises an X-ray tube for generating X-rays by causing an electron beam to collide with the same position on a target, and an X-ray detector for detecting X-rays emitted from the X-ray tube and transmitted through an inspection object, the method for determining the degree of consumption of the target of the X-ray tube, wherein the X-ray tube comprises an X-ray detector for detecting X-rays emitted from the X-ray tube and transmitted through an inspection object, the method comprising: The X-ray detector detects X-rays emitted from the X-ray tube during a predetermined period to detect an X-ray dose during the period, and measures a maximum value Imax and a minimum value Imin of the X-ray dose during the period. The X-ray dose variation rate is calculated using the maximum value Imax of the X-ray dose and the minimum value Imin of the X-ray dose, and The target consumption is determined based on the rate of change of the X-ray dose. The calculated rate of change of the X-ray dose is displayed as information indicating whether the target is being consumed. Alternatively, when the calculated rate of change of the X-ray dose exceeds a preset threshold value, it is determined that the target is being consumed.

Images