Measurement device

Abstract

Provided is a measurement device capable of suppressing the amount of charged particle beams emitted from a charged particle beam source and improving measurement accuracy. This measurement device is provided with: a radiation unit (20) in which a charged particle beam source (21) is housed; a detection unit (30) in which a detection device (31) for detecting charged particle beams emitted from a charged particle beam source is housed, the detection unit (30) being disposed at a distance from the emission unit (20); and a magnetic field generation unit (40) that generates a magnetic field between the radiation unit (20) and the detection unit (30) from one side toward the other side, in which an emission port (23a) for emitting the charged particle beam emitted from the charged particle beam source (21) to the outside is formed in the radiation unit (20) at a position facing the detection unit (30), and in which the detection unit (30) detects the charged particle beam emitted from the charged particle beam source (21). An entrance port (33a) into which the charged particle beam enters is formed at a position facing the exit port (23a).

Description

TECHNICAL FIELD

[0001] The present application relates to a measuring device. BACKGROUND

[0002] A measuring device that measures the thickness of a sheet-shaped object to be measured using charged particle rays emitted from a charged particle ray source is known (for example, refer to Patent Document 1). The measuring device has an emission section that houses the charged particle ray source inside, and a detection section that houses a detection device that detects the charged particle rays inside. An emission opening is formed in the emission section, which causes the charged particle rays emitted from the charged particle ray source to be emitted to the outside. An incidence opening is formed in the detection section, which causes the charged particle rays emitted from the emission section to be emitted to the inside. The emission section and the detection section are configured so as to be provided with a space between each other, and so that the emission opening and the incidence opening are opposed to each other. When the object to be measured is passed between the emission section and the detection section, the thickness of the object to be measured is measured based on a change in the amount of rays detected by the detection section.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 5-149775

[0004] The charged particle rays emitted from the emission opening spread radially while heading toward the incidence opening. Therefore, a part of the charged particle rays emitted from the emission opening does not reach the incidence opening. In the detection section, the amount of rays of the charged particle rays that reach the incidence opening is detected.

[0005] If too few charged particle rays reach the incidence opening, the change in the amount of rays that can be detected is small, which sometimes results in insufficient measurement accuracy of the thickness of the object to be measured. Therefore, in order to cause a sufficient amount of charged particle rays to reach the incidence opening, it is conceivable to increase the amount of charged particle rays emitted from the charged particle ray source.

[0006] However, if the amount of charged particle rays emitted from the charged particle ray source is increased, in order to ensure a large management area, the device becomes large, or a large installation space is required. SUMMARY

[0007] An object of the present application is to obtain a measuring device that can suppress the amount of charged particle rays emitted from a charged particle ray source, and that can achieve an improvement in measurement accuracy.

[0008] The present application relates to a measuring device having: a radiation section that houses a charged particle beam source inside; a detection section that houses a detection device that detects a charged particle beam emitted from the charged particle beam source inside, and is disposed apart from the radiation section by a distance; and a magnetic field generation section that causes a magnetic field from one of the radiation section and the detection section toward the other to occur between the radiation section and the detection section, in the radiation section, an exit port through which the charged particle beam emitted from the charged particle beam source is emitted to the outside is formed at a position opposite the detection section, and in the detection section, an entrance port through which the charged particle beam is made to enter to the inside is formed at a position opposite the exit port.

[0009] Effects of the Invention

[0010] According to the present application, the following effects are obtained: a measuring device that can suppress the amount of radiation of a charged particle beam emitted from a charged particle beam source and achieve an improvement in measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a perspective view showing the overall structure of the measuring device according to Embodiment 1.

[0012] Figure 2 is a cross-sectional view of the radiation section and the detection section taken at a plane including the feeding direction of the object to be measured.

[0013] Figure 3 is a cross-sectional view of the radiation section taken along the III-III line shown in FIG. 3. Figure 2

[0014] Figure 4 is a cross-sectional view of the radiation section taken along the IV-IV line shown in FIG. 4. Figure 2

[0015] Figure 5 is a view showing a modification of the magnetic field generation section.

[0016] Figure 6 is a view showing a measuring device provided with a shielding section. DETAILED DESCRIPTION

[0017] A measuring device according to one embodiment of the present application will be described in detail below with reference to the drawings. Note that the present application is not limited by the following embodiment.

[0018] 〔Embodiment 1〕

[0019] <Overall Structure of Measuring Device>

[0020] Figure 1 ​​is a perspective view showing the schematic configuration of the measurement device according to Embodiment 1. The measurement device 1 is a device that measures the thickness of a sheet-shaped object to be measured 50. As the object to be measured 50, an electrode sheet for a secondary battery, a separator sheet, paper, a plastic sheet for packaging, a sheet of building material, a sheet of functional raw material, an optical film, a metal foil are exemplified. For example, if the object to be measured 50 is an electrode sheet, a slurry is thinly and uniformly applied to the surface of an aluminum foil, and drying is performed in the next process. The same application is performed to the back surface of the aluminum foil after drying, and drying is performed. By measuring the thickness of the electrode sheet using the measurement device 1, measurement of the weight per unit area of the aluminum foil (coating unit weight) is performed.

[0021] The measurement device 1 has a frame 10, an emitting section 20, a detecting section 30, and a magnetic field generating section 40. The frame 10 has a lower frame 10a and an upper frame 10b, and is a frame-shaped member obtained by joining the lower frame 10a and the upper frame 10b at the end portions thereof. The region between the lower frame 10a and the upper frame 10b becomes a measurement space in which the thickness of the object to be measured 50 is measured.

[0022] The emitting section 20 is supported to the lower frame 10a. The emitting section 20 is capable of scanning in the longitudinal direction of the lower frame 10a (the direction indicated by the arrow Y). The detecting section 30 is supported to the upper frame 10b. The detecting section 30 is capable of scanning in the longitudinal direction of the upper frame 10b. Alternatively, the emitting section 20 can be supported to the upper frame 10b, and the detecting section 30 can be supported to the lower frame 10a.

[0023] The emitting section 20 and the detecting section 30 are arranged so as to face each other. A gap is provided between the emitting section 20 and the detecting section 30. The object to be measured 50 that moves in the direction indicated by the arrow X passes through the gap between the emitting section 20 and the detecting section 30. During the passage of the object to be measured 50, the emitting section 20 and the detecting section 30 scan in a state of facing each other.

[0024] <For the emitting section and the detecting section>

[0025] Figure 2 is a cross-sectional view in which the emitting section and the detecting section are cut at a plane including the feeding direction of the object to be measured.

[0026] The emitting section 20 has a charged particle line source 21, an emitting side housing section 22, and an emitting side pedestal 23.

[0027] A charged particle line is emitted from the charged particle line source 21. As the charged particle line, a β line, an α line, an electron beam, and the like are exemplified. In the case where the charged particle line is a β line, as the charged particle line source 21, a sealed container in which a nuclide: 85Kr as a radioactive gas is sealed is exemplified.

[0028] The radiation-side containment section 22 houses the charged particle beam source 21. The side of the radiation-side containment section 22 facing the detection section 30 is open. The radiation-side base 23 seals the opening of the detection section 30. The radiation-side base 23 is formed to be larger than the opening of the radiation-side containment section 22. A first adjacent device 24 is mounted on the radiation-side base 23 at a position adjacent to the radiation-side containment section 22.

[0029] On the radiating base 23, an exit port 23a is formed at the position where the opening of the radiating housing 22 is sealed. The exit port 23a connects the interior and exterior of the radiating housing 22. Charged particle lines emitted from the charged particle source 21 are emitted from the exit port 23a toward the exterior of the radiating housing 22.

[0030] Although the illustration is omitted, the radiating section 20 is equipped with a gate mechanism to prevent charged particle lines from being emitted from the emission port 23a when the thickness of the object being measured 50 is not being measured. The first adjacent device 24 is equipped with a power supply system, control circuitry, etc., for driving the gate mechanism.

[0031] The detection unit 30 includes a detection device 31, a detection-side receiving part 32, and a detection-side base 33.

[0032] The detection device 31 is a device for detecting the amount of charged particle lines. A detection-side housing 32 houses the detection device 31. The side of the detection-side housing 32 facing the radiation section 20 is open. A detection-side base 33 seals the opening of the detection-side housing 32. The detection-side base 33 is formed to be larger than the opening of the detection-side housing 32. A second adjacent device 34 is mounted on the detection-side base 33 at a position adjacent to the detection-side housing 32.

[0033] The detection-side base 33 and the radiation-side base 23 are positioned opposite each other with a gap. The gap between the radiation-side base 23 and the detection-side base 33 becomes the gap between the radiation section 20 and the detection section 30.

[0034] On the detection-side base 33, an inlet 33a is formed at a position that seals the opening of the detection-side receiving portion 32. Furthermore, the inlet 33a is formed opposite to the outlet 23a of the radiation portion 20. The inlet 33a allows communication between the interior and exterior of the detection-side receiving portion 32.

[0035] Charged particle lines emitted from the exit port 23a of the radiation section 20 pass through the entrance port 33a and enter the interior of the detection-side receiving section 32. The amount of charged particle lines entering the interior of the detection-side receiving section 32 is detected by the detection device 31.

[0036] The second adjacent device 34 is equipped with a power supply system, control circuit, etc. for driving the detection device 31.

[0037] <Regarding the magnetic field generating unit>

[0038] The magnetic field generating unit 40 generates a magnetic field between the radiating unit 20 and the detecting unit 30, moving from one side of the radiating unit 20 towards the other. Furthermore, in Figure 2 In the diagram, arrow Z indicates the orientation of the magnetic field when the side of the radiating section 20 is set as one side and the side of the detection section 30 is set as the other side.

[0039] The magnetic field generating unit 40 is configured to include a first coil 41a and a second coil 41b. The first coil 41a is disposed in the radiating unit 20. Figure 3 It is along Figure 2 The diagram shows a cross-sectional view of the radial portion cut off by line III-III. Furthermore, in... Figure 3 For ease of understanding, the first adjacent device 24 is omitted from the diagram.

[0040] The first coil 41a is a coil that surrounds the charged particle line source 21 with the axis 60 as the center when viewed along the axis 60 passing through the exit port 23a and the entrance port 33a. More specifically, the first coil 41a is disposed in the radiation-side base 23 as the surface 23b on the side where the radiation-side receiving portion 22 is disposed. In addition, the first coil 41a is configured to surround the radiation-side receiving portion 22 when viewed along the axis 60. Alternatively, the first coil 41a may be disposed in the surface 23c of the radiation-side base 23 opposite to the detection-side base 33. Preferably, the axis 60 passes through the center of the exit port 23a and the center of the entrance port 33a. Furthermore, the first coil 41a passes between the radiation-side receiving portion 22 and the first adjacent device 24. Therefore, it can also be said that the first adjacent device 24 is disposed adjacent to the first coil 41a.

[0041] The second coil 41b is located in the detection section 30. Figure 4 It is along Figure 2 The diagram shows a cross-sectional view of the radial portion cut off along line IV-IV. Furthermore, in... Figure 4 For ease of understanding, the second adjacent device 34 is omitted from the diagram.

[0042] The second coil 41b is a coil that surrounds the detection device 31 with the axis 60 as its center when viewed along the axis 60. More specifically, the second coil 41b is disposed in the detection-side base 33 as the surface 33b on the side where the detection-side receiving portion 32 is provided. Furthermore, the second coil 41b is configured to surround the detection-side receiving portion 32 when viewed along the axis 60. Additionally, the second coil 41b passes between the detection-side receiving portion 32 and the second adjacent device 34. Therefore, it can also be said that the second adjacent device 34 is disposed adjacent to the second coil 41b. Alternatively, the second coil 41b may also be disposed in the detection-side base 33 on the surface 33c opposite to the radiation-side base 23.

[0043] By allowing current to flow through the first coil 41a and the second coil 41b, a current is generated between the radiating section 20 and the detection section 30. Figure 2 The direction of the magnetic field is indicated by arrow Z. Furthermore, by constructing a so-called Helmholtz coil from coil 41a and coil 41b, a more uniform magnetic field can be formed between the radiating section 20 and the detection section 30.

[0044] <Determination of the thickness of the object being measured>

[0045] Return to Figure 1 In the measuring apparatus 1, when measuring the thickness of the object 50, the object 50 is passed between the radiating section 20 and the detection section 30 while they are scanning in a state where they are facing each other. During the scanning process of the radiating section 20 and the detection section 30, charged particle lines are emitted from the emission port 23a. The charged particle lines emitted from the emission port 23a pass through the object 50 and reach the detection device 31 of the detection section 30. In the measuring apparatus 1, the thickness of the object 50 is calculated based on the attenuation of the amount of charged particle lines passing through the object 50.

[0046] <For the extension of charged particle lines>

[0047] The charged particle beam emitted from the charged particle beam source 21 and exiting the exit port 23a expands radially toward the detection unit 30. Therefore, a portion of the charged particle beam emitted from the exit port 23a passes through a position deviating from the entrance port 33a and fails to reach the detection device 31.

[0048] In the measuring device 1, the thickness of the object 50 is calculated based on the attenuation of the amount of charged particle lines passing through it. Here, the greater the amount of charged particle lines reaching the detection device 31, the more accurate the thickness measurement of the object 50. Therefore, it is desirable to allow as many charged particle lines as possible emitted from the exit port 23a to enter the entrance port 33a.

[0049] In measuring device 1, such as Figure 2 As shown, a magnetic field is formed between the emitting section 20 and the detection section 30 via the magnetic field generating section 40, extending from the emitting section 20 toward the detection section 30. Here, when the direction of motion of the electrons generating the charged particle lines contains a component that is not parallel to the magnetic field, the electrons are subjected to a Lorentz force. Through the acceleration motion caused by the Lorentz force and the motion in the same direction as the magnetic field, the electrons undergo helical motion. That is, the charged particle lines emitted from the exit port 23a and expanding radially without heading toward the entrance port 33a are subjected to the Lorentz force and undergo helical motion, their direction of travel being deflected toward the entrance port 33a.

[0050] Therefore, even if the amount of charged particle lines emitted from the exit port 23a is the same, by providing the magnetic field generating unit 40, more charged particle lines can be injected into the entrance port 33a. With more charged particle lines entering the entrance port 33a, the number of charged particle lines reaching the detection device 31 also increases. Therefore, without increasing the amount of charged particle lines emitted from the exit port 23a, the measurement accuracy of the thickness of the object 50 can be improved. That is, in the measuring device 1, the emission of charged particle lines from the charged particle source 21 can be suppressed, and the measurement accuracy can be improved. By forming a Helmholtz coil using the first coil 41a and the second coil 41b, a uniform magnetic field can be used to deflect the travel direction of more charged particle lines toward the entrance port 33a.

[0051] Furthermore, by suppressing the amount of radiation from charged particle lines, the management area can be kept smaller, thus enabling the miniaturization of the measuring device 1 and the reduction of the installation space of the measuring device 1.

[0052] In addition, if the charged particle lines extend radially, the detection accuracy at the end of the measured object 50 may sometimes decrease, but by deflecting the charged particle lines, the decrease in detection accuracy of the measured object 50 can be suppressed.

[0053] Furthermore, the magnetic field generating unit 40 may not include the second coil 41b and may consist only of the first coil 41a. For the magnetic field generated from the first coil 41a, in the region approaching the first coil 41a, the orientation of the magnetic field is close to... Figure 2 Arrow Z is parallel to the direction indicated by arrow Z. Therefore, by placing the first coil 41a on the detection section 30 side, charged particle lines can be deflected in the direction indicated by arrow Z near the detection section 30, allowing more charged particle lines to enter from the entrance port 33a. Therefore, when the magnetic field generating section 40 is composed solely of the first coil 41a, it is preferable to place the first coil 41a on the detection section 30 side.

[0054] <Example of a modified magnetic field generating section>

[0055] Figure 5 This is a diagram showing a modified example of the magnetic field generating unit. In Figure 5 In, with Figure 2 Similarly, a cross-sectional view is shown where the radiating section and the detection section are cut off at the surface containing the feed direction of the object being measured. The magnetic field generating section 40 may be configured to include a first magnet 42a and a second magnet 42b.

[0056] The first magnet 42a is disposed in the radiating section 20 in the same manner as the first coil 41a. Furthermore, the shape of the first magnet 42a is also the same as that of the first coil 41a, forming a ring shape centered on the axis 60. That is, the first magnet 42a is... Figure 2 and Figure 3 The structure after the first coil 41a shown is replaced with a permanent magnet formed in a ring shape becomes the first magnet 42a. In addition, the orientation of the magnetic poles of the first magnet 42a becomes an orientation parallel to the axis 60.

[0057] The second magnet 42b is disposed in the detection unit 30 in the same manner as the second coil 41b. Furthermore, the shape of the second magnet 42b is also the same as that of the second coil 41b, forming a ring shape centered on the axis 60. That is, the second magnet 42b... Figure 2 and Figure 4 The structure after the second coil 41b shown is replaced with a permanent magnet formed in a ring shape becomes the second magnet 42b. Furthermore, the orientation of the magnetic poles of the second magnet 42b becomes parallel to the axis 60.

[0058] Furthermore, the first magnet 42a can also be constructed by dividing it into multiple parts along the circumferential direction centered on axis 60. The orientation of the magnetic poles of each of the multiple magnets is set to be parallel to axis 60.

[0059] Alternatively, the second magnet 42b can also be constructed by dividing it into multiple parts along the circumference centered on axis 60. The orientation of the magnetic poles of each of the multiple magnets is set to be parallel to axis 60.

[0060] As described above, when the magnetic field generating unit 40 is configured to include a first magnet 42a and a second magnet 42b, a magnetic field can be generated between the emitting unit 20 and the detection unit 30, moving from one side of the emitting unit 20 to the other side. This allows charged particle lines that are emitted from the exit port 23a and expand radially without heading towards the entrance port 33a to undergo a helical motion due to the Lorentz force, causing their direction of travel to deflect towards the entrance port 33a.

[0061] <Additional Examples of Shielding Sections>

[0062] Figure 6 This diagram shows a measuring device with a shielding section. (Example) Figure 6As shown, a shielding portion 70 covering the first adjacent device 24 and the second adjacent device 34 can also be provided on the measuring device 1. By providing the shielding portion 70, the first adjacent device 24 and the second adjacent device 34 can be protected from the magnetic field generated in the magnetic field generating unit 40. The shielding portion 70 is formed, for example, from a high magnetic permeability material such as permalloy.

[0063] <Other>

[0064] Below are several examples of combinations of disclosed technical features.

[0065] (1) A measuring device comprising: a radiating section that houses a charged particle line source therein; a detection section that houses a detection device for detecting charged particle lines emitted from the charged particle line source therein, and is disposed at a distance from the radiating section; and a magnetic field generating section that generates a magnetic field between the radiating section and the detection section from one side of the radiating section to the other side, wherein in the radiating section, an exit port for the charged particle lines emitted from the charged particle line source toward the outside is formed at a position opposite to the detection section, and in the detection section, an entrance port for the charged particle lines to enter the interior is formed at a position opposite to the exit port.

[0066] (2) According to the measuring device described in (1) above, the magnetic field generating unit is configured to include a first coil, which is disposed in one of the radiating unit and the detection unit, and when viewed along the axis passing through the exit port and the entrance port, surrounds one of the charged particle line source and the detection device with the axis as the center.

[0067] (3) According to the measuring device described in (2) above, the magnetic field generating part is configured to include a second coil, which is disposed in the other of the radiating part and the detection part, and when viewed along the axis, surrounds the other of the charged particle line source and the detection device with the axis as the center.

[0068] (4) The measuring device described in (3) above, wherein the first coil and the second coil constitute a Helmholtz coil.

[0069] (5) According to the measuring device described in (1) above, the magnetic field generating unit includes a first magnet disposed in one of the radiating unit and the detection unit, and when viewed along an axis passing through the exit port and the entrance port, surrounds one of the charged particle line source and the detection device with the axis as the center.

[0070] (6) According to the measuring device described in (5) above, the magnetic field generating part includes a second magnet disposed in the other of the radiating part and the detection part, and when viewed along the axis, surrounds the other of the charged particle line source and the detection device with the axis as the center.

[0071] (7) According to the measuring device described in (6) above, wherein the first magnet and the second magnet are formed in a ring shape centered on the axis.

[0072] (8) The measuring device described in (6) above, wherein the first magnet and the second magnet are divided into a plurality of parts along the circumferential direction.

[0073] (9) The measuring device according to any one of (1) to (8) above, further comprising: an adjacent device disposed adjacent to the magnetic field generating unit; and a shielding unit that surrounds the adjacent device and shields the magnetic field generated from the magnetic field generating unit.

[0074] (10) The measuring apparatus described in any one of (1) to (9) above, wherein the charged particle line source is a β line source that emits β lines.

[0075] (11) The measuring device according to any one of (1) to (10) above, wherein it further comprises a frame that supports the radiating part and the detecting part so that scanning is performed in such a state that the exit port and the entrance port are opposite each other.

[0076] Explanation of the label

[0077] 1. Measuring apparatus

[0078] 10 Framework

[0079] 10a bottom frame

[0080] 10b Top Frame

[0081] 20 Radiology Department

[0082] 21 Charged Particle Wire Source

[0083] 22 Radiation-side containment section

[0084] 23 Radial side base

[0085] 23a Exit Port

[0086] 23b and 23c

[0087] 24 The first adjacent device

[0088] 30. Testing Department

[0089] 31 Detection device

[0090] 32 Detection-side containment section

[0091] 33. Detection side base

[0092] 33a Inlet

[0093] 33b and 33c

[0094] 34 Second Adjacent Device

[0095] 40 Magnetic field generating unit

[0096] 41a First coil

[0097] 41b Second coil

[0098] 50 analytes

[0099] 60 axis

[0100] 70. Shelter

Claims

1. A measuring device comprising: The radiation section houses the source of charged particle beams. The detection unit, which houses a detection device for detecting charged particle beams emitted from the charged particle beam source, is arranged at a distance from the emission unit; and A magnetic field generating unit that generates a magnetic field between the radiating unit and the detecting unit, moving from one side of the radiating unit and the detecting unit towards the other side. In the radiating section, an exit port for the charged particle lines emitted from the charged particle line source and directed outward is formed at a position opposite to the detection section. In the detection unit, the entrance port into which the charged particle line enters is formed at a position opposite to the exit port.

2. The measuring device according to claim 1, wherein, The magnetic field generating unit is configured to include a first coil, which is disposed in one of the radiating unit and the detection unit, and when viewed along an axis passing through the exit port and the entrance port, surrounds one of the charged particle line source and the detection device with the axis as the center.

3. The measuring device according to claim 2, wherein, The magnetic field generating unit is configured to include a second coil, which is disposed in the other of the radiating unit and the detection unit, and when viewed along the axis, surrounds the other of the charged particle line source and the detection device with the axis as the center.

4. The measuring device according to claim 3, wherein, The first coil and the second coil constitute a Helmholtz coil.

5. The measuring device according to claim 1, wherein, The magnetic field generating unit includes a first magnet disposed in one of the radiating unit and the detection unit, and when viewed along an axis passing through the exit port and the entrance port, surrounds one of the charged particle line source and the detection device with the axis as the center.

6. The measuring device according to claim 5, wherein, The magnetic field generating unit includes a second magnet disposed in the other of the radiating unit and the detection unit, and when viewed along the axis, surrounds the other of the charged particle line source and the detection device with the axis as the center.

7. The measuring apparatus according to claim 6, wherein, The first magnet and the second magnet are formed in a ring shape centered on the axis.

8. The measuring apparatus according to claim 6, wherein, The first magnet and the second magnet are divided into multiple parts along the circumferential direction.

9. The measuring apparatus according to any one of claims 1 to 8, wherein, It also has: Adjacent devices, which are arranged adjacent to the magnetic field generator; and A shielding section surrounds the adjacent device and shields the magnetic field generated from the magnetic field generating section.

10. The measuring device according to claim 1, wherein, The charged particle line source is a β-line source that emits β-lines.

11. The measuring device according to claim 1, wherein, It also has a frame that supports the radiating part and the detection part so that scanning can be performed with the exit port and the entrance port facing each other.

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