Radiation source installation jig and measurement system

Abstract

To provide a radiation source installation jig capable of appropriately mounting a jig to a detector in a shielding body, and a measurement system.SOLUTION: A radiation source installation jig 10 comprises a first end part 31, a second end part 32, and a support part 33. The first end part 31 is attached to a tip part 22a of an end cap housing 22 of a radiation detector 11. The second end part 32 holds a radiation source 10a. The support part 33 supports the first end part 31 and the second end part 32 at a predetermined distance in a first axial direction Q parallel to a central axis P. The second end part 32 comprises a contact part 32a and a peripheral part 32b that are integrally formed. The contact part 32a is in contact with the radiation source 10a. The peripheral part 32b is provided at a peripheral edge of the contact part 32a, and has a tip surface 32B that does not protrude outward with respect to a tip surface 32A of the contact part 32a in the first axial direction Q.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a radiation source installation jig and a measurement system. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a radiation source holder that positions and fixes a radiation source such as a standard radiation source at a predetermined position relative to a radiation detector when measuring the relative efficiency of the radiation detector (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Radioactivity Measurement Method Series 7: Gamma-ray Spectrometry Using Germanium Semiconductor Detectors," Nuclear Regulation Authority, 2020, p.178 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when the radiation source holder according to the above-described conventional technology is attached to a radiation detector inside the shield, it is necessary to ensure a space within the shield that is necessary for attaching the radiation source holder to an appropriate head of the radiation detector in response to a change in the position of the head (such as the tip of an end cap) due to, for example, replacement of the radiation detector, etc. However, when increasing the space within the shield while ensuring the desired shielding performance, problems arise in that the increased mass of the shield limits the locations where the shield can be installed and increases the cost required to configure the shield.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a radiation source installation jig and a measurement system that enable the jig to be properly attached to a detector within a shielding body. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above object, the present invention employs the following aspects. (1) A radiation source installation jig according to one aspect of the present invention is a radiation source installation jig that positions and fixes a radiation source with respect to an end cap of a radiation detector inside a shielding body, and includes: a first end portion attached to a tip portion of the end cap; a second end portion that holds the radiation source; and a support portion that supports the first end portion and the second end portion at a predetermined distance in an axial direction parallel to a central axis, wherein the second end portion includes a contact portion that contacts the radiation source; and a peripheral portion that is provided on the periphery of the contact portion and has a tip surface that does not protrude outward in the axial direction beyond the tip surface of the contact portion.

[0007] (2) In the radiation source installation jig according to (1) above, when the first axis direction, which is the axial direction, is inclined at a predetermined angle or less with respect to a second axis direction parallel to the central axis line of the end cap, the tip surface of the peripheral portion may not protrude outward beyond the tips of the radiation source and the contact portion in the second axis direction.

[0008] (3) In the radiation source installation jig according to (2) above, the first end portion may be formed to have a size necessary for changing its posture with respect to the end cap among a first state, a second state, and a third state. The first state may be a state in which only a part of the tip of the end cap is inserted into the first end portion by tilting the first axial direction with respect to the second axial direction by the predetermined angle or less. The second state may be a state in which the tilt of the first axial direction with respect to the second axial direction from the first state is gradually reduced to increase a portion of the tip of the end cap that is inserted into the first end portion, or the tilt of the first axial direction with respect to the second axial direction is gradually increased from the third state to reduce a portion of the tip of the end cap that is inserted into the first end portion. The third state may be a state in which the first axial direction and the second axial direction are parallel to each other, and the entire tip of the end cap is inserted into the first end portion.

[0009] (4) A measurement system according to one aspect of the present invention comprises a radiation source installation jig described in any one of (1) to (3) above, the shielding body, and the radiation detector to which the radiation source installation jig is attached inside the shielding body.

[0010] (5) A measurement system according to one aspect of the present invention comprises a shielding body, an electromagnetic wave or sound wave detector, and a jig for positioning and fixing a source of electromagnetic waves or sound waves relative to a head of the detector inside the shielding body, the jig comprising a first end attached to the tip of the head, a second end for holding the source, and a support for supporting the first end and the second end at a predetermined distance in an axial direction parallel to a central axis, the second end comprising a contact portion in contact with the source, and a peripheral portion provided on the periphery of the contact portion and having a tip surface that does not protrude outward in the axial direction beyond the tip surface of the contact portion. [Effects of the Invention]

[0011] According to the radiation source installation jig according to the aspect (1) above, for example, when the radiation source protrudes outward beyond the tip surface of the contact portion, the tip surface of the peripheral portion can be prevented from protruding outward beyond the radiation source and the tip of the contact portion when the axial direction of the radiation source installation jig is tilted relative to the axial direction of the end cap. By tilting the axial direction of the radiation source installation jig relative to the axial direction of the end cap at the beginning of attachment of the radiation source installation jig to the end cap or at the end of detachment, a portion of the end cap is inserted into the first end portion. Compared to a case where a portion of the end cap is not inserted into the first end portion, such as when the axial direction of the radiation source installation jig and the axial direction of the end cap are parallel, the distance between the radiation source and the tip of the contact portion and the tip surface of the end cap in the axial direction of the end cap can be reduced. This reduces the need to increase the space within the shielding body, and allows the radiation source installation jig to be properly attached to and detached from the end cap of the radiation detector within the shielding body.

[0012] In the case of (2) above, when the first axis direction is inclined with respect to the second axis direction by a predetermined angle or less, the tip surface of the peripheral portion can be prevented from protruding outward beyond the tips of the radiation source and the contact portion. By inclining the first axis direction with respect to the second axis direction by a predetermined angle or less at the beginning of attachment of the radiation source installation jig to the end cap or at the end of detachment, the distance in the second axis direction between the tips of the radiation source and the contact portion and the tip surface of the end cap can be reduced. This makes it possible to prevent the need to increase the space within the shielding when attaching or detaching the radiation source installation jig to or from the end cap of the radiation detector inside the shielding.

[0013] In the case of (3) above, even when the first axis direction is tilted at an angle equal to or smaller than a predetermined angle with respect to the second axis direction, the radiation source installation jig can be properly attached to and detached from the end cap of the radiation detector.

[0014] According to the measurement system according to the aspect (4) above, when attaching and detaching the radiation source installation jig to and from the end cap of the radiation detector inside the shielding, it is possible to prevent the need to increase the space inside the shielding, thereby preventing an increase in the mass of the shielding and limitations on the location where the shielding can be installed, and preventing an increase in the cost required for configuring the shielding.

[0015] According to the measurement system according to the aspect (5) above, when attaching and detaching a jig to and from the detector head inside the shield, it is possible to prevent the need to increase the space inside the shield, thereby preventing an increase in the mass of the shield and limitations on the location where the shield can be installed, and preventing an increase in the cost required to configure the shield. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a configuration diagram showing an example of a measurement system including a radiation source installation jig according to an embodiment of the present invention, with a radiation shield cut away. [Figure 2] FIG. 2 is a cross-sectional view of the radiation source installation jig according to the embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view showing an example of a state in which the radiation source installation jig according to the embodiment of the present invention is attached to the radiation detector inside the radiation shield. [Figure 4] 1A and 1B are cross-sectional views showing a first state of the radiation source installation jig according to the embodiment of the present invention and a state of a first comparative example. [Figure 5] 1A and 1B are cross-sectional views showing a first state of a radiation source installation jig according to an embodiment of the present invention and a radiation source installation jig of a second comparative example. [Figure 6] 1A and 1B are cross-sectional views showing a first state of a radiation source installation jig according to a first modified example of an embodiment of the present invention and a radiation source installation jig of a second comparative example. [Figure 7] FIG. 10 is a view of a radiation source installation jig according to a first modified example of an embodiment of the present invention, viewed from a first axis direction. [Figure 8] 10A and 10B are cross-sectional views showing a first state and a third state of a radiation source installation jig according to a second modified example of the embodiment of the present invention. [Figure 9] 10A and 10B are cross-sectional views showing a first state and a third state of a radiation source installation jig according to a third modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] A radiation source installation jig and a measurement system according to an embodiment of the present invention will be described below with reference to the accompanying drawings. <Measurement system> FIG. 1 is a configuration diagram showing an example of a measurement system 1 including a radiation source installation jig 10 according to an embodiment, in which a radiation shield 12 is cut away. 1, the measurement system 1 of this embodiment includes a radiation source installation jig 10, a radiation detector 11, and a radiation shielding body 12. The measurement system 1 further includes, for example, a mount 14, a base 15, a detector stand 16, a position adjustment mechanism 17, and a slide mechanism 18. The radiation source installation jig 10 of this embodiment is used to position and fix the radiation source 10a relative to the radiation detector 11 inside the radiation shielding body 12. The radiation detector 11 detects radiation emitted from the radiation source 10a positioned and fixed inside the radiation shielding body 12. In the following description, the X-axis, Y-axis, and Z-axis directions, which are orthogonal to each other in three-dimensional space, are parallel to each other. For example, the Z-axis direction is parallel to the up-down direction of the measurement system 1, the Y-axis direction is parallel to the left-right direction of the measurement system 1, and the X-axis direction is parallel to the front-rear direction of the measurement system 1.

[0018] The radiation detector 11 is a semiconductor detector such as a germanium semiconductor detector or a silicon semiconductor detector. The radiation detector 11 is a vertical cryostat 21 that holds a semiconductor crystal (not shown) such as a germanium crystal or a silicon crystal that is sensitive to radiation in a vacuum region inside an end cap housing 22 that has a radiation entrance window (not shown).

[0019] The inside of the cryostat 21 is cooled by thermal contact with a cooling rod (not shown) made of copper immersed in liquid nitrogen stored inside the dewar 23 . A crystal electrode (not shown) formed on the semiconductor crystal is connected to a charge-type preamplifier (not shown) housed inside the end cap housing 22 . The charge-type preamplifier outputs an output signal pulse having a peak value corresponding to the energy of the radiation incident on the semiconductor crystal from an output terminal (not shown) exposed to the outside.

[0020] The radiation shield 12 houses the radiation detector 11 and the radiation source installation jig 10 that holds the radiation source 10a to be measured, and shields the radiation detector 11 from background radiation. The radiation shielding body 12 has an outer shape formed, for example, in a box shape by combining multiple members. The multiple members are, for example, a first member 12a, a second member 12b, a third member 12c, a fourth member 12d, and a fifth member 12e. The first member 12a forms the upper portion of the radiation shielding body 12 in the up-down direction (e.g., vertical direction, etc.). The second member 12b forms the side and rear portions integrated in the front-rear direction and left-right direction (e.g., horizontal direction, etc.) perpendicular to the up-down direction of the radiation shielding body 12. The third member 12c and the fourth member 12d form the lower portion of the radiation shielding body 12 in the up-down direction. The third member 12c has a space (cutout portion) formed from the front end in the front-rear direction to the rear, into which the end cap housing 22 of the radiation detector 11 is inserted. The fourth member 12d is disposed in front of the cutout portion of the third member 12c and is attached to and detached from the third member 12c by moving in the front-rear direction. The fifth member 12e forms the front part in the front-rear direction of the radiation shielding body 12. The fifth member 12e forms an opening and closing door that opens and closes the opening formed by the first member 12a, the second member 12b, the third member 12c, and the fourth member 12d.

[0021] The radiation shielding body 12 includes a lead shielding portion 13a containing lead, a steel shielding portion 13b containing steel provided so as to cover the surface of the lead shielding portion 13a, and a non-conductive coating film (not shown) for corrosion prevention or the like that covers the surface of the steel shielding portion 13b. The radiation shielding body 12 includes, on its inner surface, a first lining (not shown) containing oxygen-free copper and a second lining (not shown) containing a resin such as acrylic.

[0022] The measurement system 1 includes, for example, a stand 14, a base 15, a detector stand 16, a position adjustment mechanism 17, and a slide mechanism 18. The pedestal 14 supports the radiation shielding body 12. The pedestal 14 has, for example, a box-like external shape. The pedestal 14 is formed from a material such as steel 14b having a surface coated with a non-conductive coating 14a for corrosion prevention or the like. The pedestal 14 has an opening / closing door 14c at its front end in the front-to-rear direction for opening and closing the interior. The pedestal 14 houses a dewar 23 inside. The base 15 supports the mount 14. The outer shape of the base 15 is, for example, a plate shape. The base 15 is made of a material such as steel having a surface coated with a non-conductive coating film for corrosion prevention or the like.

[0023] The detector base 16 supports the dewar 23 of the radiation detector 11 inside the gantry 14. The detector base 16 has, for example, a plate-like outer shape. The detector base 16 is made of a metal material such as aluminum. The position adjustment mechanism 17 adjusts the position of the detector stage 16 in the vertical direction. The slide mechanism 18 moves the detector table 16 forward and backward to carry the dewar 23 of the radiation detector 11 into and out of the gantry 14 .

[0024] <Radiation source installation jig> The radiation source installation jig 10 of the embodiment is a so-called radiation source holder, and positions and fixes the radiation source 10 a to the end cap housing 22 of the radiation detector 11 inside the radiation shielding body 12 . FIG. 2 is a cross-sectional view of the radiation source installation jig 10 according to the embodiment. As shown in FIG. 2, the radiation source installation jig 10 includes, for example, a first end portion 31, a second end portion 32, and a support portion 33. The first end 31 is attached to the tip 22a of the end cap housing 22 of the radiation detector 11. The outer shape of the first end 31 is, for example, a cylindrical (hollow columnar) cap type having an end with an axial through-hole formed therein, corresponding to the hollow columnar end cap housing 22. The inner diameter of the main body (cylindrical portion) of the first end 31 is formed to be at least larger than the outer diameter of the end cap housing 22.

[0025] The second end 32 holds the radiation source 10a. The outer shape of the second end 32 is, for example, a hollow truncated cone shape with a recess and a through-hole formed coaxially in the axial direction to correspond to the disk-shaped radiation source 10a. The second end 32 includes, for example, a contact portion 32a and a peripheral portion 32b that are integrally formed. The contact portion 32a contacts the periphery of the radiation source 10a. The contact portion 32a has an outer shape, for example, a circular plate shape, with a recess and a through-hole formed coaxially in the axial direction. The contact portion 32a fixes the radiation source 10a in a state in which the radiation source 10a protrudes outward from a tip end surface 32A of the contact portion 32a, for example, in an axial direction (first axial direction) Q parallel to the central axis P of the radiation source installation jig 10. The outward direction in the first axial direction Q is the direction opposite to the first end 31 side, with the second end 32 in the first axial direction Q as a reference. The tip end surface 32A of the contact portion 32a is, for example, perpendicular to the first axial direction Q, and its position in the first axial direction Q is constant.

[0026] The peripheral edge portion 32b is provided on the periphery of the contact portion 32a. The outer shape of the peripheral edge portion 32b is, for example, a hollow cone with a through hole formed in the axial direction, and is a tapered shape whose outer diameter gradually decreases outward in the first axial direction Q. The peripheral edge portion 32b has a tip surface 32B that does not protrude outward beyond the tip surface 32A of the contact portion 32a in the first axial direction Q. The tip surface 32B of the peripheral edge portion 32b is inclined at a predetermined angle with respect to the direction perpendicular to the first axial direction Q, like the side surface of a truncated cone, so that the distance from the tip surface 32B to the first end portion 31 in the first axial direction Q gradually decreases as the tip surface 32B moves away from the central axis P in the direction perpendicular to the first axial direction Q. As will be described later, the tip surface 32B of the peripheral portion 32b is formed so as not to protrude outward beyond the tips of the radiation source 10a and the contact portion 32a in the second axis direction S (e.g., the Z axis direction) when the first axis direction Q is inclined at a predetermined angle θ or less with respect to a second axis direction S parallel to the central axis O of the end cap housing 22.

[0027] The support portion 33 supports the first end portion 31 and the second end portion 32 at a predetermined distance in the first axial direction Q. The outer shape of the support portion 33 is, for example, cylindrical. For example, the outer diameter of the support portion 33 is smaller than the outer diameter of the first end portion 31 and is the same as the outer diameter of the second end portion 32.

[0028] Fig. 3 is a cross-sectional view showing an example of a state in which the radiation source installation jig 10 according to the embodiment is attached to the radiation detector 11 inside the radiation shielding body 12. Fig. 4 is a cross-sectional view showing a first state of the radiation source installation jig 10 according to the embodiment and a state of a first comparative example. 3 , when the radiation source installation jig 10 is attached to the tip portion 22a of the end cap housing 22 of the radiation detector 11 inside the radiation shielding body 12, the radiation source installation jig 10 is inserted into the radiation shielding body 12 with the first axis direction Q of the central axis P inclined at a predetermined angle θ or less with respect to a second axis direction S parallel to the central axis O of the end cap housing 22. By inclining the first axis direction Q with respect to the second axis direction S at the predetermined angle θ or less, the radiation source installation jig 10 reduces the distance from the inner surface (top surface) 12A of the first member 12a of the radiation shielding body 12 in the second axis direction S, for example, compared to when the first axis direction Q is not inclined with respect to the second axis direction S. The inclination direction of the first axis direction Q with respect to the second axis direction S is, for example, the opposite direction to the direction of movement of the end cap housing 22 relative to the end cap housing 22 in a direction perpendicular to the central axis O of the end cap housing 22.

[0029] As shown in FIG. 4, at the beginning of attaching the radiation source installation jig 10 to the end cap housing 22 or at the end of removing the radiation source installation jig 10, the radiation source installation jig 10 is moved in a direction perpendicular to the central axis O of the end cap housing 22 with the first axis direction Q inclined at a predetermined angle θ or less with respect to the second axis direction S. When the radiation source installation jig 10 is attached to or detached from the end cap housing 22, the position of the radiation source installation jig 10 is changed to, for example, a first state, a second state, or a third state.

[0030] The first state is a state in which only a portion of the tip portion 22a of the end cap housing 22 is inserted inside the first end portion 31 by inclining the first axial direction Q of the central axis P at a predetermined angle θ or less with respect to the second axial direction S of the central axis O. The second state is a state in which the portion of the tip portion 22a of the end cap housing 22 inserted into the first end portion 31 is increased by gradually reducing the inclination of the first axis direction Q with respect to the second axis direction S from the first state, or the portion of the tip portion 22a of the end cap housing 22 inserted into the first end portion 31 is reduced by gradually increasing the inclination of the first axis direction Q with respect to the second axis direction S from the third state. In the third state, the first axis direction Q and the second axis direction S are parallel to each other, and the entire tip portion 22a of the end cap housing 22 is inserted into the first end portion 31. The first end 31 of the radiation source installation jig 10 is formed to have a size necessary for changing its position relative to the end cap housing 22 between the first state, the second state, and the third state.

[0031] Regarding the distance in the second axis direction S between the tips of the radiation source 10a and the contact portion 32a of the radiation source installation jig 10 and the surface (tip surface) of the tip portion 22a of the end cap housing 22, the distance h in the first state is smaller than the distance h1 in the state of the first comparative example. The state of the first comparative example is a state in which the radiation source installation jig 10 is moved in a direction perpendicular to the central axis O of the end cap housing 22, with the first axis direction Q and the second axis direction S parallel to each other, at the beginning of installation of the radiation source installation jig 10 or at the end of removal. Since a portion of the tip portion 22a of the end cap housing 22 is inserted into the first end portion 31 in accordance with the inclination of the first axis direction Q relative to the second axis direction S, the distance h in the first state is smaller than the distance h1 in the state of the first comparative example, compared to when the tip portion 22a is not inserted into the first end portion 31.

[0032] FIG. 5 is a cross-sectional view showing a first state of the radiation source installation jig 10 according to the embodiment and a radiation source installation jig 40 of a second comparative example. A radiation source installation jig 40 of the second comparative example shown in FIG. 5 includes a third end 41 instead of the second end 32 of the radiation source installation jig 10 of the embodiment. The third end 41 holds the radiation source 10a. The third end 41 has an outer shape of, for example, an annular plate with a recess and a through-hole formed coaxially in the axial direction to correspond to the disk-shaped radiation source 10a. The third end 41 fixes the radiation source 10a in a state where the radiation source 10a protrudes outward from the tip end surface 41A in, for example, an axial direction (third axis direction) Q1 parallel to the central axis P1 of the radiation source installation jig 40 of the second comparative example. The outward direction of the third axis direction Q1 is the direction opposite to the first end 31 side with respect to the third end 41 in the third axis direction Q1. The tip end surface 41A of the third end 41 is parallel to a direction perpendicular to the third axis direction Q1 and is constant in position in the third axis direction Q1.

[0033] The third end 41 of the radiation source installation jig 40 of the second comparative example includes the contact portion 32a of the radiation source installation jig 10 of the embodiment, and the tip surface 41A of the third end 41 includes the tip surface 32A of the contact portion 32a. For example, when the first axis direction Q and the third axis direction Q1 are parallel to each other, the tip surface 41A of the third end 41 of the second comparative example is located at the same position as the tip surface 32A of the contact portion 32a of the embodiment in each of the axis directions Q and Q1, and protrudes outward beyond the tip surface 32B of the contact portion 32a. A distance h2 between the radiation source 10a and the tip of the third end 41 of the radiation source installation jig 40 of the second comparative example and the surface (tip surface) of the tip portion 22a of the end cap housing 22 in the second axis direction S is greater than the distance h in the first state in the embodiment.

[0034] As described above, according to the radiation source installation jig 10 of this embodiment, by tilting the first axis direction Q with respect to the second axis direction S at the beginning of installation on the end cap housing 22 or at the end of removal, it is possible to prevent an increase in the distance in the second axis direction S between the tips of the radiation source 10a and the contact portion 32a and the surface (tip surface) of the end cap housing 22. When installing and removing the radiation source installation jig 10 on and from the end cap housing 22 of the radiation detector 11 inside the radiation shielding 12, it is possible to prevent the need to increase the space inside the radiation shielding 12. The first end 31 of the radiation source installation jig 10 is formed to a size necessary to change its position relative to the end cap housing 22 between the first state, the second state, and the third state, so that the radiation source installation jig 10 can be properly attached to and detached from the end cap housing 22.

[0035] The measurement system 1 according to this embodiment can prevent the need to increase the internal space of the radiation shielding body 12, prevent an increase in the mass of the radiation shielding body 12, prevent limitations on the locations where the radiation shielding body 12 can be installed, and prevent an increase in the cost required to configure the radiation shielding body 12.

[0036] Modifications of the above-described embodiment will now be described. In the above-described embodiment, the peripheral edge portion 32b of the second end portion 32 has a tapered shape in the first axial direction Q, but is not limited to this. For example, at least a portion of the tip surface 32B of the peripheral edge portion 32b may be formed so as not to protrude outward beyond the tip surface 32A of the contact portion 32a in the first axial direction Q. Fig. 6 is a cross-sectional view showing a first state of the radiation source installation jig 10A according to a first modified example of the embodiment and a radiation source installation jig 40 according to a second comparative example. Fig. 7 is a view of the radiation source installation jig 10A according to the first modified example of the embodiment as seen from a first axis direction Q. 6 and 7, the radiation source installation jig 10A according to the first modification includes the second end portion 51 of the first modification, instead of the second end portion 32 of the embodiment. The second end portion 51 of the first modification includes, for example, the contact portion 32a of the embodiment and the peripheral edge portion 51a of the first modification, which are integrally formed.

[0037] The peripheral edge portion 51a of the first modified example is provided on the periphery of the contact portion 32a. The outer shape of the peripheral edge portion 51a is, for example, a hollow cylinder with a through hole formed in the axial direction. The peripheral edge portion 51a has a first tip surface 51A and a second tip surface 51B. The first tip surface 51A is perpendicular to the first axial direction Q and is located at the same position as the tip surface 32A of the contact portion 32a in the first axial direction Q. Like the tip surface 32B of the embodiment, the second tip surface 51B does not protrude outward beyond the tip surface 32A of the contact portion 32a in the first axial direction Q. The second tip surface 51B is inclined at a predetermined angle with respect to the direction perpendicular to the first axial direction Q so that the distance between the second tip surface 51B and the first end 31 in the first axial direction Q gradually decreases as the second tip surface 51B moves away from the central axis P in the perpendicular direction. The second tip surface 51B is formed so as not to protrude outward beyond the tips of the radiation source 10a and the contact portion 32a in the second axis direction S when the first axis direction Q is inclined at an angle θ or less relative to the second axis direction S, similar to the tip surface 32B of the embodiment.

[0038] In the above-described embodiment, the peripheral edge portion 32b of the second end portion 32 has a tapered shape in the first axial direction Q, but is not limited to this. For example, the tip surface 32B of the peripheral edge portion 32b may be formed so as to be perpendicular to the first axial direction Q and to be positioned closer to the first end portion 31 than the tip surface 32A of the contact portion 32a. FIG. 8 is a cross-sectional view showing a first state and a third state of a radiation source installation jig 10B according to a second modified example of the embodiment. 8, a radiation source installation jig 10B according to the second modification includes a second end portion 52 of the second modification, instead of the second end portion 32 of the embodiment. The second end portion 52 of the second modification includes, for example, the contact portion 32a of the embodiment and the peripheral portion 52a of the second modification, which are integrally formed.

[0039] The peripheral portion 52a of the second modified example is provided on the periphery of the contact portion 32a. The peripheral portion 52a has an outer shape, for example, an annular plate with a through hole formed in the axial direction. A tip surface 52A of the peripheral portion 52a is perpendicular to the first axis direction Q. The tip surface 52A is located closer to the first end portion 31 than the tip surface 32A of the contact portion 32a in the first axis direction Q. Similar to the tip surface 32B of the embodiment, the tip surface 52A is formed so as not to protrude outward beyond the radiation source 10a and the tip of the contact portion 32a in the second axis direction S when the first axis direction Q is inclined at an angle θ or less with respect to the second axis direction S.

[0040] In the above-described embodiment, the outer shape of the support portion 33 is cylindrical, but this is not limiting. For example, the outer shape of the support portion 33 may be formed in another shape, such as a rod shape. FIG. 9 is a cross-sectional view showing a first state and a third state of a radiation source installation jig 10C according to a third modified example of the embodiment. As shown in FIG. 9 , a radiation source installation jig 10C according to the third modification includes at least one support member 53 of the third modification, instead of the support member 33 of the second modification. The radiation source installation jig 10C of the third modification includes, for example, two support members 53. The outer shape of the support member 53 of the third modification is, for example, rod-shaped. Both end portions in the first axis direction Q of the support member 53 of the third modification are fixed to a recess 31a formed in the first end portion 31 and a recess 52b formed in the second end portion 52. The recess 31a of the first end portion 31 is formed, for example, on the surface of the first end portion 31 facing the second end portion 52 in the first axis direction Q. The recess 52b of the second end portion 52 is formed, for example, on the surface of the second end portion 52 facing the first end portion 31 in the first axis direction Q.

[0041] In the above-described embodiment, the measurement system 1 includes the radiation source installation jig 10, the radiation detector 11, and the radiation shielding body 12, but is not limited to this. For example, the measurement system according to the fourth modification of the embodiment may measure electromagnetic waves or sound waves other than radiation. The measurement system according to the fourth modification includes, for example, a shield for electromagnetic waves or sound waves, a detector, and a jig for positioning and fixing the source of the electromagnetic waves or sound waves relative to the head of the detector inside the shield. The jig has a first end attached to the tip of the detector head, a second end that holds the source, and a support that supports the first end and the second end at a predetermined distance in an axial direction parallel to the central axis. The second end portion includes a contact portion that contacts the generation source, and a peripheral portion that is provided on the periphery of the contact portion and has a tip surface that does not protrude outward in the axial direction beyond the tip surface of the contact portion.

[0042] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0043] 1...measurement system, 10, 10A, 10B, 10C...radiation source installation jig, 10a...radiation source, 11...radiation detector, 12...radiation shield, 22...end cap housing, 22a...tip portion, 31...first end, 32...second end, 32a...contact portion, 32A...tip surface, 32b...periphery, 32B...tip surface, 33...support portion, 51...second end, 51a...periphery, 51A...first tip surface, 51B...second tip surface, 52...second end, 52a...periphery, 52A...tip surface, 53...support portion, O...central axis, P...central axis, Q...first axial direction, S...second axial direction, θ...predetermined angle.

Claims

1. A radiation source installation jig that positions and fixes a radiation source with respect to an end cap of a radiation detector inside a shield, a first end portion attached to a tip portion of the end cap; a second end that holds the radiation source; and a support portion that supports the first end portion and the second end portion at a predetermined distance in an axial direction parallel to a central axis line; Equipped with The second end is a contact portion that contacts the radiation source; a peripheral portion provided on the periphery of the contact portion and having a tip surface that does not protrude outward beyond the tip surface of the contact portion in the axial direction; Equipped with The tip surface of the peripheral edge portion is When a first axis direction, which is the axial direction, is inclined at a predetermined angle or less with respect to a second axis direction parallel to a central axis line of the end cap, the radiation source does not protrude outward beyond the tip of the contact portion in the second axis direction. A radiation source installation jig characterized by:

2. the first end is formed to a size necessary for changing its position relative to the end cap among a first state, a second state, and a third state; the first state is a state in which only a portion of the tip end portion of the end cap is inserted into the first end portion by inclining the first axial direction with respect to the second axial direction at the predetermined angle or less, the second state is a state in which the portion of the tip end of the end cap inserted into the first end portion is increased by gradually reducing the inclination of the first axial direction with respect to the second axial direction from the first state, or the portion of the tip end of the end cap inserted into the first end portion is decreased by gradually increasing the inclination of the first axial direction with respect to the second axial direction from the third state, The third state is a state in which the first axial direction and the second axial direction are parallel to each other and the entire tip of the end cap is inserted into the first end.

2. The radiation source installation jig according to claim 1.

3. a radiation source installation jig according to claim 1 or 2; The shield; the radiation detector to which the radiation source installation jig is attached inside the shield; and Equipped with A measurement system characterized in that:

4. A shield; a detector of electromagnetic waves or acoustic waves; a jig for positioning and fixing a source of electromagnetic waves or sound waves relative to the head of the detector inside the shield; Equipped with The jig is a first end attached to a tip of the head; a second end that holds the source; a support portion that supports the first end portion and the second end portion at a predetermined distance in an axial direction parallel to a central axis line; Equipped with The second end is a contact portion that contacts the source; a peripheral portion provided on the periphery of the contact portion and having a tip surface that does not protrude outward beyond the tip surface of the contact portion in the axial direction; Equipped with The tip surface of the peripheral edge portion is When a first axis direction, which is the axial direction, is inclined at a predetermined angle or less with respect to a second axis direction parallel to the central axis of the head, the contact portion does not protrude outward from the tip of the contact portion in the second axis direction. A measurement system characterized in that:

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