Personal dosemeter

Abstract

To reduce a quantity of a member existing on a front side of a case while keeping a function of a clip in a personal dosemeter.SOLUTION: A case includes an enlarged portion 16, a transition part 18, and a main body 20. A radiation sensor is arranged inside the enlarged portion 16. A clip 14 includes a shoulder part 124 and an arm part 126. A base structure 120 and an upright structure 121 are connected by a pin 122. In an attachment state of the clip 14, the shoulder part 124 is pre-deformed by elasticity, and pressing force 140 is applied to a front surface 24 of the case from the clip 14.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a personal dosimeter, and more particularly to a clip for a personal dosimeter. [Background technology]

[0002] A personal dosimeter is a radiation measuring device used to manage personal exposure in radiation handling facilities such as nuclear power plants and medical facilities. The radiation detected by a personal dosimeter includes X-rays, gamma rays, beta rays, and neutrons.

[0003] A personal dosimeter generally has a case that houses a radiation sensor and a clip attached to the front of the case. For example, when the personal dosimeter is placed in a worker's pocket, the pocket fabric is inserted into the slit between the case and the clip, and the fabric is sandwiched between the clip and the case.

[0004] Patent Document 1 discloses a personal dosimeter equipped with a clip. The clip has a movable piece and a metal spring. The metal spring is specifically a metal spring. An elastic force is applied from the metal spring to the movable piece. The end of the movable piece (operation tab) is located near the detection unit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-3882 Summary of the Invention [Problem to be solved by the invention]

[0006] In personal dosimeters, in order to prevent a decrease in detection sensitivity and a deterioration in directional characteristics, it is desirable to reduce the amount of materials arranged on the front side of the case housing the radiation sensor. Specifically, for example, it is desirable to eliminate the metal spring of the clip. However, in conventional personal dosimeters, simply eliminating the metal spring would prevent the clip from performing its intended function.

[0007] An object of the present invention is to reduce the number of members present on the front side of the case of a personal dosimeter while maintaining the functionality of the clip. [Means for solving the problem]

[0008] A personal dosimeter according to the present invention includes a case having a front surface, a radiation sensor housed in the case for detecting radiation, and a clip having a shoulder fixed to the case and an arm extending from the shoulder along the front surface of the case to form a slit between the clip and the front surface of the case, wherein in a closed state in which the arm is in contact with the front surface of the case, the arm is already elastically deformed, and as a result, an initial pressing force is applied from the arm to the case, and in an open state in which the arm is separated from the front surface of the case, the arm is further elastically deformed. [Effects of the Invention]

[0009] According to the present invention, in a personal dosimeter, the amount of members present on the front side of the case can be reduced while maintaining the function of the clip. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing the front side of the personal dosimeter according to the embodiment. [Figure 2] FIG. 2 is a perspective view showing the rear side of the personal dosimeter according to the embodiment. [Figure 3] FIG. 2 is a diagram showing an example of a state in which a personal dosimeter is worn. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] 1A and 1B are diagrams showing the original and open states of the clip; [Figure 8] FIG. 2 is a cross-sectional view showing a detection unit according to the first embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a detection unit according to a second embodiment. [Figure 10] 10A and 10B are diagrams showing a clip according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment will be described with reference to the drawings.

[0012] (1) Overview of the embodiment A personal dosimeter according to an embodiment has a case, a radiation sensor, and a clip. The case has a front surface. The radiation sensor is housed within the case. Radiation is detected by the radiation sensor. The clip has a shoulder and an arm. The shoulder is a portion fixed to the case. The arm is a portion extending from the shoulder along the front surface of the case. A slit is formed between the arm and the front surface of the case. In a closed state in which the arm is in contact with the front surface of the case, the arm is already elastically deformed. This causes an initial pressing force to be exerted from the arm to the case. In an open state in which the arm is separated from the front surface of the case, the arm is further elastically deformed.

[0013] In the above configuration, a clip with elastically deformed arms is fixed to the case. After the clip is fixed to the case, a restoring force continues to act from the arms to the case unless the arms are opened. This restoring force is the initial pressing force, which corresponds to the minimum or base value of the clamping force. In the open state, the arms further elastically deform. The magnitude of the initial pressing force can be adjusted by changing the material, shape, etc. of the arms, or by changing the amount of initial elastic deformation.

[0014] With the above configuration, the arms themselves can generate a closing force, eliminating the need for a metal spring or the like to generate the closing force, thereby reducing the amount of material on the front side of the case.

[0015] In the embodiment, assuming the original shape of the arm before elastic deformation, the depth (estimated depth) to which the arm penetrates from the front surface of the case into the interior of the case is 0.5 mm or more. The estimated depth may be 0.7 mm or more, or 0.9 mm or more. If the initial elastic deformation is too large, operability will decrease, so the upper limit of the estimated depth may be set within the range of 2 to 8 mm.

[0016] The personal dosimeter according to the embodiment further includes a fixing structure for detachably fixing the shoulder portion to the case. The fixing structure has a base structure, an upright structure, and a fixing member. The base structure is provided on the front of the case. The upright structure is provided on the shoulder portion. The fixing member is a member for fixing the upright structure to the base structure. The base structure is a first engaging portion, and the upright structure is a second engaging portion. The upright structure is fixed to the base structure with the arm portion elastically deformed. The fixing member is used for this fixing. After fixing, the elastically deformed state of the arm portion is maintained.

[0017] In an embodiment, the standing structure has a bottom surface that is joined to the front surface of the case to determine the standing posture of the standing structure. With this configuration, the position and posture of the shoulder are determined by the joining of the front surface of the case and the bottom surface of the standing structure.

[0018] In one embodiment, the fixing member includes a removable pin that straddles the base structure and the upright structure. With this configuration, the clip body, including the arm and shoulder, can be easily replaced by removing the pin. Note that the clip may be integral with the case in whole or in part, as long as the arm can exert an initial pressing force on the case.

[0019] In this embodiment, the case is composed of an enlarged portion, a transition portion, and a main body, arranged from top to bottom, when the central axis direction of the case is defined as the up-down direction. A radiation sensor is disposed in the enlarged portion. The front surface of the enlarged portion extends forward of the front surface of the main body. The transition portion is a slope that connects the front surface of the enlarged portion and the front surface of the main body. The shoulder portion is located below the enlarged portion.

[0020] A slit is formed between the rear surface of the clip and the front surface of the case. To ensure a stable attachment, it is better to raise the height of the upper end of the slit. In other words, it is better to bring the installation height of the shoulder closer to the installation height of the radiation sensor. However, if the installation height of the shoulder is simply raised, the clip will affect the radiation detected by the radiation sensor. In other words, it will worsen the directional characteristics. In contrast, if an enlarged portion is provided in the case, it becomes possible to shift the installation position of the radiation sensor forward. If the installation position of the radiation sensor is shifted forward, even if the installation position of the shoulder is raised, the clip will no longer affect the radiation reaching the radiation sensor, or the effect of this effect can be reduced.

[0021] In this embodiment, the shoulder portion has a tip surface, a first inclined surface, and a second inclined surface. The tip surface is a surface that protrudes forward from the front surface of the enlarged portion and widens in the width direction of the case. The first inclined surface is a surface that is continuous with the tip surface and widens to near the front surface of the enlarged portion. The second inclined surface is a surface that is continuous with the tip surface and widens to the front surface of the arm portion.

[0022] Conventional clips generally have an operating tab. The operating tab is a part that is operated when opening and moving the clip body. In this embodiment, the shoulder portion does not have an operating tab, and the shoulder portion has a first inclined surface. Therefore, the problem of the operating tab deteriorating the directional characteristics does not occur.

[0023] In an embodiment, the arm has an upper end, a lower end, and an intermediate portion. The upper end is a portion connected to the shoulder. The intermediate portion is a portion between the upper end and the lower end. The intermediate portion has a narrowed shape when viewed from the front. This configuration makes the intermediate portion more susceptible to elastic deformation. In an embodiment, the lower end has a shape that curves forward. In this case, when the arm is closed, a wedge-shaped gap is created between the rear surface of the lower end and the front surface of the case. A fingertip may be inserted into this gap to operate the lower end.

[0024] (2) Details of the embodiment 1 shows the front side of a personal dosimeter 10 according to an embodiment. The personal dosimeter 10 is a portable radiation measuring device for managing personal radiation exposure in radiation handling facilities such as nuclear power plants and medical facilities. For example, the personal dosimeter is worn by a person (user) working in each facility.

[0025] In FIG. 1, the y direction is parallel to the longitudinal direction of the personal dosimeter 10. The y direction corresponds to the up-down direction when the personal dosimeter 10 is worn. The x direction is the width direction. The x direction corresponds to the left-right direction when the personal dosimeter 10 is worn. The z direction is the thickness direction. When viewed from the personal dosimeter 10, the +z direction is the forward direction and the -z direction is the backward direction. In other words, the +z direction corresponds to the non-human body side and the -z direction corresponds to the human body side.

[0026] The personal dosimeter 10 has a hollow case 12. The case 12 is made of, for example, resin. The case 12 has an elongated shape extending along the y direction. A clip 14 is provided on the front surface 24 of the case 12. The clip 14 is used when attaching the personal dosimeter to clothing or the like. The clip 14 is made of, for example, resin. An example of the resin is ABS resin. The clip 14 will be described in detail later.

[0027] The case 12 is broadly divided into an enlarged portion 16, a transition portion 18, and a main body 20. These are multiple portions that are aligned from top to bottom when the personal dosimeter 10 is worn. The end of the main body 20 is a cap 22. The case 12 has a central axis C. The central axis C is parallel to the y direction. The thickness of the enlarged portion 16 in the z direction is greater than the thickness of the main body 20 in the z direction. That is, the front surface of the enlarged portion 16 protrudes further forward (in the z direction) than the front surface of the main body 20. The thickness of the transition portion 18 in the z direction varies along the y direction, and more specifically, decreases along the +y direction. The front surface of the transition portion 18 is inclined. The width of the case 12 in the x direction is the same at every position in the y direction. However, both ends of the case 12 in the y direction are rounded.

[0028] A detection unit is housed within the enlarged portion 16. The detection unit has a radiation sensor, as will be described later. A detection central axis 26 passes through the center of the sensitive surface of the radiation sensor disposed within the enlarged portion 16. Reference numeral 28 indicates radiation coming from the front. In this embodiment, the radiation to be detected is gamma rays or X-rays. Other types of radiation, such as beta rays, may also be detected. Multiple types of radiation may be detected simultaneously.

[0029] 2 shows the rear side of the personal dosimeter 10. A display 30 and an operation unit 32 are provided on the rear surface of the case. The display 30 is, for example, a liquid crystal display. The display 30 displays the dose equivalent rate, the cumulative dose equivalent, etc. The operation unit 32 has two buttons, specifically a power button and a display switching button.

[0030] 3 shows an example of how a personal dosimeter is worn. The personal dosimeter 10 is inserted into a pocket 36 provided in the clothing 34 of a worker 33. The clip 14 is in an open state due to an operation 39 of the worker's fingers. The clip 14 has a clip body 38. The clip body 38 has a shoulder portion 124 and an arm portion 126. The shoulder portion 124 is a portion that is fixed to the case. The arm portion 126 is a portion that extends downward from the shoulder portion 124 and is also a portion that is elastically deformable.

[0031] A slit 37 is formed between the arm 126 and the front face 24 of the case, and the fabric of the pocket 36 is inserted into the slit 37. When the clip 14 is then returned to the closed state, the fabric is sandwiched between the arm 126 and the front face 24 of the case. In the state shown in Figure 3, radiation 28 coming from the front is detected.

[0032] 4 is an exploded perspective view of the clip 14. As described above, the clip 14 has the clip body 38. The clip body 38 is made up of a shoulder portion 124 and an arm portion 126. The fixing structure 119 has a base structure 120, an upstanding structure 121, and a pin 122. The pin 122 is a fixing member.

[0033] The base structure 120 has two bases 120A and 120B spaced apart in the x-direction. Each of the bases 120A and 120B protrudes forward from the front surface of the case. Each of the bases 120A and 120B has a pin hole 202 into which a pin 122 is inserted. Each of the bases 120A and 120B is installed across a transition portion from the main body of the case.

[0034] The upright structure 121 is provided on the shoulder portion 124. The upright structure 121 has two upright plates 121A and 121B spaced apart in the x direction and an inclined plate 121C connecting the two upright plates 121A and 121B. Each of the upright plates 121A and 121B extends in the yz direction. The shoulder portion 124 has an internal space surrounded by the two upright plates 121A and 121B and the inclined plate 121C. The internal space has an opening facing the +y direction. The upright structure 121 has a bottom surface that straddles and adheres to the front surface of the main body and the front surface of the transition portion of the case. Specifically, the bottom surface is composed of the bottom surface of the first upright plate 121A, the bottom surface of the second upright plate 121B, and the bottom surface of the inclined plate 121C. Each of the upright plates 121A and 121B has a pin hole 200 into which the pin 122 is inserted.

[0035] When attaching clip 14 to a case, standing structure 121 is coupled to base structure 120. At this time, pin 122 is inserted into two pin holes 200, 202. Since pin 122 is inserted in a removable state, clip 14 can be removed from the case by removing pin 122. In other words, clip 14 can be replaced, for example.

[0036] When clip 14 is attached, as will be described in detail later, an elastically deformed state of arm 126 is formed, and clip 14 is fixed to the case by fixing structure 119 while maintaining that elastically deformed state. Conversely, elastic deformation of arm 126 is necessary as a prerequisite for inserting pin 122 into pin holes 200, 202. When clip 14 is attached, the bottom surface of upright structure 121 is in close contact with the front surface of the case, and upright structure 121 assumes a specific posture. In other words, shoulder 124 is fixed in a specific position, and shoulder 124 assumes a specific posture.

[0037] 5 shows the attached state of the clip 14. The clip body 38 consists of a shoulder 124 and an arm 126. The shoulder 124 spans and is fixed to the transition section 18 and the body 20. The arm 126 extends from the shoulder 124 along the front surface 24 of the case.

[0038] The front surface 24 of the case is provided with a base structure 120, while the shoulder 124 is provided with an upstanding structure 121. As described above, the pin 122 is a member for fixing the shoulder 124 to the base structure 120. The bottom surface 130 of the upstanding structure 121 is joined to the transition portion 18 and the front surface 132 of the main body 20. The position and orientation of the shoulder 124 are determined by this joint and the action of the pin 122.

[0039] H0 indicates the level of the front surface of the main body 20 in the z direction. H1 indicates the level of the front surface of the enlarged portion 16 in the z direction. The relationship H0 < H1 holds. That is, the front surface of the enlarged portion 16 protrudes forward more than the front surface of the main body 20. Thereby, in the z direction, it is possible to shift the position of the sensitive surface of the radiation sensor forward. Conversely, in the z direction, it is possible to lower the position of the clip 14.

[0040] The shoulder portion 124 has a tip surface 124A, a first inclined surface 124B, and a second inclined surface 124C. The tip surface 124A protrudes forward more than the front surface of the enlarged portion 16. The tip surface 124A is a curved surface that extends in the x direction and is curved within the yz plane. The first inclined surface 124B is continuous with the tip surface 124A and extends to the vicinity of the front surface of the enlarged portion 16. The second inclined surface 124C is continuous with the tip surface 124A and is also continuous with the front surface 127 of the arm portion 126. The shoulder portion 124 does not have an operating tab (a protrusion that protrudes forward of the radiation sensor).

[0041] A protrusion 138 protruding in the -z direction is provided on the rear surface of the arm portion 126. On the other hand, two protrusions 136 protruding in the +z direction are provided on the front surface of the main body 20. The protrusion 138 abuts against the flat surface between the two protrusions 136.

[0042] When attaching the clip 14 to the case, the shoulder portion 124 is pushed into the -z direction by the assembler toward the front surface 24 of the case. Then, the shoulder portion 124 rotates slightly counterclockwise in FIG. 5, and the bottom surface 130 of the upright mechanism 121 abuts against the front surface 24 of the case. In that process, since the protrusion 138 abuts against the front surface of the case, the arm portion 126 is naturally warped, that is, the arm portion 126 is elastically deformed.

[0043] The upright structure 121 is fixed to the base structure 120 using the pin 122. In the fixed state, the elastically deformed state of the arm 126 is maintained. That is, a pressing force 140 continues to act from the protrusion 138 to the front surface 24 of the case as a restoring force generated by the elastic deformation. When using the clip 14, for example, the user inserts a fingertip into the wedge-shaped gap generated between the end 126C of the arm 126 and the front surface 24 of the case, and the end 126C is pulled up in the +z direction. This generates a restoring force in the arm 126 that is greater than the initial restoring force. This restoring force is used as a clamping force to hold the pocket fabric.

[0044] As described above, in the clip 14 according to the embodiment, a pressing force for clamping the cloth is generated based on the restoring force due to the initial elastic deformation of the arm portion 126. Therefore, there is no need to provide a metal spring for generating a clamping force.

[0045] The detection central axis 26 passes through the center of the sensitive surface 142 and is perpendicular to the sensitive surface 142. The imaginary line 144A is inclined, for example, by +60 degrees with respect to the detection central axis 26 in the yz plane. The imaginary line 144B is inclined, for example, by -60 degrees with respect to the detection central axis 26 in the yz plane. The intersection angle θ1 between the imaginary lines 144A and 144B is, for example, 120 degrees.

[0046] Although shoulder 124 is attached to a position close to enlarged portion 16, clip 14 does not extend into the area (sensor field of view) between imaginary lines 114A and 144B in the yz plane. Furthermore, there are no metal springs or operating tabs on the front side of the case. Therefore, deterioration of directional characteristics due to clip 14 is effectively prevented.

[0047] 6 shows the front of the clip body 38. An arm 126 extends from the shoulder 124 in the y direction. The arm 126 has an upper end 126A, an intermediate portion 126B, and a lower end 126C. The upper end 126A and the lower end 126C have a large width in the x direction. The intermediate portion 126B is narrowed. This makes the intermediate portion 126B more easily deformed when the arm 126 elastically deforms.

[0048] In Figure 7, reference numeral 126-1 indicates the original shape of the arm when it is attached. Reference numeral 126-2 indicates the open state of the arm after attachment. H0 indicates the level of the front surface of the case. In the initial state, the lower end of the protrusion 138 abuts against the front surface of the case, and the level of the lower end of the protrusion 128 in the initial state is H0.

[0049] In the attached state, if the arm is allowed to return to its original shape, that is, if the arm is assumed to be in its original shape, the level of the bottom end of protrusion 138 will be Ha. If H0 is set to zero, Ha will be a negative value. The difference (penetration amount) between H0 and Ha is D. The optimal difference D can vary depending on the length of the arm, the shape of the arm, the material that makes up the arm, etc.

[0050] In this embodiment, D is 0.5 mm or more, and preferably 0.7 or 0.9 mm or more. The maximum value of the difference D can be set arbitrarily, but is generally set within the range of 2 to 8 mm. Incidentally, when the arms are further elastically deformed to form an open state, the level of the lower end of the protrusion 138 becomes Hb. Hb is a positive value.

[0051] A first example of a detector housed in the enlarged portion will be described with reference to Fig. 8. The detector 46 shown in Fig. 8 detects gamma rays. X-rays may also be detected together with gamma rays.

[0052] The detection unit 46 is housed in the case 12, and more specifically, the detection unit 46 is housed in the enlarged portion 16. The detection unit 46 has an assembly 55, a front shield cover 48, a rear shield cover 50, and a first energy filter 54. The assembly 55 is fixed on the substrate 40. The assembly 55 has a radiation sensor 56 and a second energy filter 62. The assembly 55 is enclosed in a non-contact manner by the front shield cover 48 and the rear shield cover 50. The shape of the opening edge of the front shield cover 48 and the shape of the opening edge of the rear shield cover 50 are the same.

[0053] The radiation sensor 56 is, for example, a silicon photosensor. The radiation sensor 56 is made up of a sensor body 58 and conductive legs 60. The sensor body 58 has a sensitive portion. The gamma rays 28A are detected in the sensitive portion.

[0054] The conductive leg 60 consists of a pair of legs. Each leg has a first portion 67 and a second portion 68. An end of the first portion 67 is fixed to the sensor body 58. An end of the second portion 68 is fixed to the substrate 40. The first portion 67 is a horizontal portion that is approximately parallel to the y direction. The second portion 68 is a vertical portion that is approximately parallel to the z direction. The first portion 67 and the second portion 68 are connected to each other via a bent portion 70.

[0055] The substrate 40 has a first end 40A and a second end that are spaced apart in the y-direction, i.e., the longitudinal direction. In other words, the substrate 40 has a first end 41 that includes the first end 40A and a second end that includes the second end. The detection portion 46 is provided on the first end 41. The second end of each leg is connected to the substrate 40 near the first end 40A. In other words, the conductive legs 60 are provided between the sensor body 58 and the first end 40A in the y-direction.

[0056] The front shield cover 48 has a recess 52 recessed toward the rear. A first energy filter 54 is disposed in the recess 52. The first energy filter 54 is made of a metal such as copper. The first energy filter 54 has a constant thickness and is in the form of a plate extending in the x and y directions. The center of the first energy filter 54 is on the central detection axis.

[0057] The bottom surface of the recess 52 and the back surface of the first energy filter 54 are adhered with double-sided adhesive tape 72. In other words, the first energy filter 54 is fixed inside the recess 52. A gap G1 exists between the front shield cover 48 (and the first energy filter 54) and the case 12, and the front shield cover 48 (and the first energy filter 54) is separated from the case 12.

[0058] In the assembly 55, the substrate 40 and the second energy filter 62 are adhered to each other with a double-sided adhesive tape 64, and the sensor main body 58 and the second energy filter 62 are adhered to each other with a double-sided adhesive tape 66. The double-sided adhesive tape 64 and the double-sided adhesive tape 66 each function as a cushion sheet having elasticity or vibration absorption properties.

[0059] The second energy filter 62 is made of a metal such as copper, similar to the first energy filter 54. The second energy filter 62 and the first energy filter 54 may be made of a plurality of types of metal.

[0060] A gap G2 exists between the sensor main body 58 and the front shield cover 48. That is, the sensor main body 58 is separated from the front shield cover 48. The rear shield cover 50 covers the back surface of the first end 41. A gap G3 exists between the rear shield cover 50 and the case 12, separating the rear shield cover 50 from the case 12. The detection unit 46 has multiple electronic circuits such as preamplifiers, but these are not shown in the figure. These electronic circuits are provided inside the front shield cover 48 and the rear shield cover 50.

[0061] Gamma rays 28A coming from the front pass through the first energy filter 54 and reach the sensitive part of the radiation sensor 56. The first energy filter 54 is provided to improve the energy characteristics of the radiation sensor, thereby enabling accurate measurement of gamma ray doses across a range from low energy to high energy.

[0062] A portion of the gamma rays reflected or scattered by the human body passes through the second energy filter 62 and reaches the sensitive part of the radiation sensor 56. A portion of the gamma rays reflected or scattered by the second energy filter 62 also reaches the sensitive part of the radiation sensor 56. The second energy filter 62, like the first energy filter 54, is provided to improve the energy characteristics of the radiation sensor. Since the second energy filter 62 is provided in addition to the first energy filter 54 and is located near the sensor main body 58, advantages such as improved energy characteristics, improved sensitivity, and improved directional characteristics can be obtained.

[0063] The front shield cover 48 and the rear shield cover 50 also function as auxiliary energy filters. The shapes, materials, thicknesses, etc. of the first energy filter 54, the second energy filter 62, the front shield cover 48, and the rear shield cover 50 are adjusted to optimize the final energy characteristics.

[0064] Next, a second example of the detection unit will be described with reference to Fig. 9. The detection unit 80 shown in Fig. 9 detects X-rays. Gamma rays may also be detected together with X-rays.

[0065] The detection unit 80 is housed within the case 12; specifically, the detection unit 80 is housed within the enlarged portion 16. The detection unit 80 includes an assembly 86, a front shield cover 82, and a rear shield cover 84. The assembly 86 is fixed onto the substrate 40. The assembly 86 includes a radiation sensor 88, an energy filter 100, an energy filter 102, and an energy filter 108. The energy filters 100 and 102, taken as a whole, are a first energy filter that acts on radiation from the front (including oblique directions). The energy filter 108 is a second energy filter that acts on radiation from the rear. The assembly 86 is enclosed in a non-contact manner by the front shield cover 82 and the rear shield cover 84. The shape of the opening edge of the front shield cover 82 and the rear shield cover 84 are the same. The front shield cover 82 has a protrusion 83 that protrudes forward.

[0066] The radiation sensor 88 is, for example, a silicon photosensor. The radiation sensor 88 is made up of a sensor body 90 and conductive legs 92. The sensor body 90 has a sensitive portion. X-rays are detected in the sensitive portion.

[0067] The conductive leg 60 consists of a pair of legs. Each leg has a first portion 94 and a second portion 96. An end (first end) of the first portion 94 is fixed to the sensor body 90. An end (second end) of the second portion 96 is fixed to the substrate 40. The first portion 94 is a horizontal portion parallel to the y direction. The second portion 96 is a vertical portion parallel to the z direction. The first portion 94 and the second portion 96 are connected to each other via a bent portion 98.

[0068] The substrate 40 has a first end 40A and a second end that are spaced apart in the y direction, i.e., the longitudinal direction. In other words, the substrate 40 has a first end 41 that includes the first end 40A and a second end that includes the second end. The detection unit 80 is provided on the first end 41. The second end of each leg is connected to the substrate 40 near the first end 40A. In other words, the conductive legs 92 are provided between the sensor body 90 and the first end 40A in the y direction.

[0069] A gap G1 exists between the front shield cover 82 and the case 12, separating the front shield cover 82 from the case 12. A gap G2 exists between the front shield cover 82 and the assembly 86, separating the assembly 86 from the front shield cover 82.

[0070] Energy filters 100 and 102 are fixed to the sensor main body 90. The energy filter 102 covers the upper surface of the sensor main body 90. The energy filter 102 also covers three of the four side surfaces of the sensor main body 90 (the three side surfaces to which the conductive legs 92 are not connected).

[0071] The energy filter 100 comprises a large diameter portion and a small diameter portion. The large diameter portion is placed on the top plate of the energy filter 102. An opening is formed in the top plate of the energy filter 102, and the small diameter portion is inserted into the opening. The energy filter 100 has a through-hole 100A. The through-hole 100A has, for example, a cylindrical shape. The through-hole 100A may also have a conical or mortar shape.

[0072] Energy filter 100 is adhered to energy filter 102 via double-sided adhesive tape 104. Energy filter 102 is adhered to sensor body 90 via double-sided adhesive tape 106. The central axis of energy filter 100 coincides with the central detection axis. The central detection axis is an axis that passes through the center of the sensitive part in sensor body 90 and is perpendicular to the sensitive part.

[0073] The sensor body 90 is spaced forward from the front surface of the substrate 40. An energy filter 108 is disposed between the sensor body 90 and the front surface of the substrate 40. Specifically, the substrate 40 and the energy filter 62 are adhered to each other with a double-sided adhesive tape 110, and the sensor body 90 and the energy filter 108 are adhered to each other with a double-sided adhesive tape 112. The double-sided adhesive tape 110 and the double-sided adhesive tape 112 each function as a cushion sheet having elasticity or vibration absorption properties.

[0074] The energy filters 100, 102, and 108 are each made of a metal such as copper, but may each be made of multiple types of metal.

[0075] A gap G2 exists between the assembly 86 and the front shield cover 82. In other words, the assembly 86 is separated from the front shield cover 82. A portion of the assembly 86 fits into the internal space of the protrusion 83 without contacting it. The rear shield cover 84 covers the back surface of the first end 41. A gap G3 exists between the rear shield cover 84 and the case 12. This separates the rear shield cover 84 from the case 12. The detection unit 80 has multiple electronic circuits such as a preamplifier, but these are not shown in the figure. These electronic circuits are provided inside the front shield cover 82 and the rear shield cover 84.

[0076] A portion of the X-rays 28B from the front passes through the energy filters 100 and 102 and reaches the sensitive portion of the radiation sensor 88. Another portion of the X-rays 28B from the front passes through the inside of the through-hole 100A formed in the energy filter 100 and reaches the sensitive portion of the radiation sensor 88.

[0077] A portion of the X-rays reflected or scattered by the human body passes through the energy filter 108 and reaches the sensitive portion of the radiation sensor 88. In addition, a portion of the X-rays reflected or scattered by the energy filter 108 also reaches the sensitive portion of the radiation sensor 88.

[0078] The energy filters 100, 102, and 108 are each intended to improve the energy characteristics of the radiation sensor. In addition to the energy filters 100 and 102, the energy filter 108 is provided, and moreover, the energy filter 108 is provided in the vicinity of the sensor body 90, thereby providing the advantages of improved energy characteristics, improved sensitivity, and improved directional characteristics.

[0079] The front shield cover 82 and the rear shield cover 84 function as auxiliary energy filters. The shapes, materials, thicknesses, etc. of the energy filters 100, 102, 108, the front shield cover 82, and the rear shield cover 84 are adjusted so as to achieve the best final energy characteristics.

[0080] A clip according to a modified example is shown in Figure 10. Clip 152 has a holder 154 and a clip body 156. Clip body 156 is made up of a shoulder portion 158 and an arm portion 160. Holder 154 and clip body 156 are integrated.

[0081] The holder 154 functions as a fixed structure. The holder 154 has an annular shape, and the case 150 is inserted into the holder 154. The holder 154 is provided across the transition portion and the main body of the case 150. The holder 154 is attachable to and detachable from the case 150.

[0082] The shoulder portion 158 is attached to the holder 154. This indirectly fixes the shoulder portion 158 to the case 150. An arm portion 160 extends from the shoulder portion 158 along the front surface of the case 150. The arm portion 160 has a flat portion 160A and a curved portion 160B. The middle portion of the curved portion 160B abuts against the front surface of the case 150.

[0083] When clip 152 is attached to case 150, arm 160 is already elastically deformed, and pressing force 162 is exerted from arm 160 onto the front surface of case 150. In this state, part of pressing force 162 may be generated by the elastic deformation of shoulder 158.

[0084] When clip 152 is removed from case 150, arm 160 returns to its original shape, and curved portion 160B sinks into holder 154. That is, curved portion 160B moves downward until it returns to its original shape. When clip 152 is attached, arm 160 is pushed upward from the front surface of the case, causing arm 160 to elastically deform.

[0085] According to the above embodiment, the arm portion itself can generate a closing force, eliminating the need for a metal spring or the like to generate the closing force. This reduces the amount of material present on the front side of the case. This improves the directional characteristics of the personal dosimeter and reduces the number of parts that make up the personal dosimeter. [Explanation of symbols]

[0086] 10 Personal dosimeter, 12 Case, 14 Clip, 38 Clip body, 124 Shoulder part, 126 Arm part, 119 Fixation structure, 120 Base structure, 121 Standing structure, 122 Pin.

Claims

1. a case having a front surface; a radiation sensor housed in the case for detecting radiation; a clip having a shoulder portion fixed to the case and an arm portion extending from the shoulder portion along the front surface of the case, the arm portion forming a slit between the clip and the front surface of the case; Including, In the closed state where the arm portion is in contact with the front surface of the case, the arm portion is already elastically deformed, and an initial pressing force is exerted from the arm portion to the case, In an open state in which the arm portion is separated from the front surface of the case, the arm portion further elastically deforms. A personal dosimeter characterized by:

2. 2. The personal dosimeter according to claim 1, When the original shape of the arm portion is assumed not to be elastically deformed, the depth to which the arm portion penetrates into the interior of the case from the front surface of the case is 0.5 mm or more. A personal dosimeter characterized by:

3. 2. The personal dosimeter according to claim 1, a fixing structure that detachably fixes the shoulder portion to the case, The fixing structure includes: a base structure provided on the front surface of the case; a standing structure provided on the shoulder portion; a fixing member that fixes the standing structure to the base structure; A personal dosimeter comprising:

4. 4. The personal dosimeter according to claim 3, The standing structure has a bottom surface that is joined to the front surface of the case to determine the standing posture of the standing structure. A personal dosimeter characterized by:

5. 4. The personal dosimeter according to claim 3, The fixing member includes an insertable / removable pin arranged across the base structure and the upright structure. A personal dosimeter characterized by:

6. 2. The personal dosimeter according to claim 1, The case is configured with an enlarged portion, a transition portion, and a main body, which are arranged from top to bottom when the central axis direction of the case is defined as the up-down direction, The radiation sensor is disposed within the enlargement; The front surface of the enlarged portion is located forward of the front surface of the main body, a front surface of the transition portion is a slope continuing to a front surface of the enlarged portion and a front surface of the main body; The shoulder portion is located below the enlarged portion. A personal dosimeter characterized by:

7. 7. The personal dosimeter according to claim 6, The shoulder portion is a tip end surface that projects forward from the front surface of the enlarged portion and widens in the width direction of the case; a first inclined surface that is connected to the tip surface and extends to the vicinity of the front surface of the enlarged portion; a second inclined surface connected to the tip surface and connected to a front surface of the arm portion; A personal dosimeter comprising:

8. 2. The personal dosimeter according to claim 1, The arm portion is an upper end portion connected to the shoulder portion; A lower end portion and an intermediate portion between the upper end portion and the lower end portion, the intermediate portion having a narrowed shape when viewed from the front; A personal dosimeter comprising:

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