JP2014035249A - Radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a radiation detector to reduce the number of steps.SOLUTION: A radiation detector 10A comprises: a first radiation detection element 30 for detecting first radiation X1; a second radiation detection element 40 for detecting second radiation X2 having energy higher than that of the first radiation X1; and a wiring board 20 having wiring patterns for transmitting electric signals output from the radiation detection elements 30, 40. The first radiation detection element 30 is bump-mounted on the wiring pattern on one surface of the wiring board 20. The second radiation detection element 40 is bump-mounted on the wiring pattern on the other surface of the wiring board 20. Metal layers 25, as filters through which the second radiation X2 is selectively transmitted, are provided in a region positioned between the first radiation detection element 30 and the second radiation detection element 40 inside the wiring board 20.

Description

  The present invention relates to a radiation detector.

  Patent Document 1 discloses a dual energy X-ray imaging apparatus. In this dual energy X-ray imaging apparatus, a photodiode array and a scintillator for detecting low energy X-rays are provided on one surface of the wiring board, and a photodiode array and scintillator for detecting high energy X-rays are provided. It is provided on the other surface of the wiring board. On one surface of the wiring board, a filter for selectively passing high energy X-rays toward the other surface is arranged side by side with the photodiode array and scintillator for low energy X-rays. Yes.

  Patent Document 2 discloses a CT scanner for baggage inspection. The CT scanner includes a plurality of detection units for detecting X-rays. In each detector, a photodiode array and a scintillator for detecting low energy X-rays are arranged on one surface of the copper plate, and a photodiode array and a scintillator for detecting high energy X-rays are arranged on the other side of the copper plate. It is arranged on the surface.

  Patent Document 3 discloses a radiation detector formed by laminating a solid-state photodetector between two scintillators. The solid-state photodetector has a large number of solid-state photodetectors made of photodiodes and thin film transistors on both surfaces of a substrate made of resin.

EP 1010021 Specification US Patent Application Publication No. 2004/120454 Japanese Patent Laid-Open No. 7-27865

  There is known a radiation detector that selectively detects two types of radiation having different energies, for example, soft X-rays and hard X-rays. FIG. 7 is a side sectional view showing an example of the structure of such a radiation detector. The radiation detector 100 shown in the figure includes a wiring board 101 and two radiation detection elements 103 and 105 mounted on one surface 101 a of the wiring board 101. The radiation detection element 103 is an element for detecting soft X-rays, and includes a scintillator 103a that converts soft X-rays into light and a light detection element 103b that detects light emitted from the scintillator 103a. . The radiation detection element 105 is an element for detecting hard X-rays, and includes a scintillator 105a that converts hard X-rays into light, and a light detection element 105b that detects light emitted from the scintillator 105a. ing. On one surface 101a of the wiring board 101, an A / D converter 109 that receives electrical signals from the photodetecting elements 103b and 105b, and a controller IC 111 that processes a signal output from the A / D converter 109 are provided. Bump mounted.

  The two radiation detection elements 103 and 105 are arranged on the wiring board 101 in the thickness direction so as to detect soft X-rays and hard X-rays that arrive from a certain position from the same angle. These radiation detection elements 103 and 105 are fixed to the wiring board 101 by inserting respective terminals into sockets 113 and 115 provided on the wiring board 101. A filter that shields soft X-rays and selectively transmits hard X-rays is disposed between the radiation detection element 103 disposed on the upper side and the radiation detection element 105 disposed on the lower side. . However, in the radiation detector 100 shown in FIG. 7, since the two radiation detection elements 103 and 105 are arranged so as to overlap each other, the structure becomes complicated and the number of processes increases.

  The present invention has been made in view of such problems, and an object thereof is to provide a radiation detector that can simplify the structure and reduce the number of steps.

  In order to solve the above-described problems, a radiation detector according to the present invention includes a first radiation detection element that detects first radiation and a second radiation that detects second radiation having higher energy than the first radiation. And a wiring board having a wiring pattern for transmitting electrical signals output from the first and second radiation detecting elements, wherein the first radiation detecting element is provided on one surface of the wiring board. Bump-mounted on the upper wiring pattern, and the second radiation detection element is bump-mounted on the wiring pattern on the other surface of the wiring board, and the first radiation detection element is inside the wiring board. A metal layer serving as a filter that selectively transmits the second radiation is provided in a region located between the second radiation detection element.

  In this radiation detector, the first radiation detecting element for detecting the first radiation with low energy is bump-mounted on one surface of the wiring board, and the second radiation for detecting the second radiation with high energy is detected. The radiation detection element is bump-mounted on the other surface of the wiring board. As a result, the radiation detection element can be attached to the wiring board simultaneously with the mounting of other signal processing chips, etc., so that the structure is simplified and the number of processes is reduced compared to the structure shown in FIG. can do. Further, in the structure shown in FIG. 7, the radiation detection element is fixed to the wiring board by inserting the terminal of the radiation detection element into the socket. However, like the above-described radiation detector, the first and second radiation detection elements are fixed. Each of the radiation detection elements is bump-mounted on both sides of the wiring board, so that the reliability can be improved as compared with the structure shown in FIG.

  Further, in this radiation detector, a metal layer as a filter that selectively transmits the second radiation is provided inside the wiring board. Since such a structure is suitably realized by the interlayer wiring layer of the wiring board, the structure can be simplified and the number of processes can be reduced without employing a special structure for providing a filter. In addition, the degree of freedom of arrangement of the filter and the radiation detection element can be increased as compared with a case where the filter is arranged side by side with the radiation detection element on one surface of the wiring board (see, for example, Patent Document 1).

  The radiation detector may be characterized in that a plurality of metal layers are laminated in the thickness direction of the wiring board, and the plurality of metal layers are separated from each other. Thereby, the effect | action as a filter which selectively permeate | transmits 2nd radiation can be show | played more effectively. In addition, such a structure can be easily realized by providing a plurality of interlayer wiring layers of the wiring board, so that an increase in the number of processes can be suppressed. In addition, since the plurality of metal layers are laminated so as to be separated from each other in this way, it is possible to increase the thickness of the entire filter portion including the interlayer portion of the plurality of metal layers. Compared with the case where it comprises, the radiation which goes around the edge of a filter and reaches | attains a 2nd radiation detection element can further be reduced.

  The radiation detector further includes a signal processing chip mounted on the wiring board and electrically connected to the first and second radiation detection elements via the wiring pattern, and the metal layer includes the signal processing chip. It may be characterized by being connected to a reference potential line. Thereby, the electric potential of a metal layer can be stabilized and the noise added to an electric signal can be reduced.

  The radiation detector may be characterized in that the signal processing chip is mounted on the other surface of the wiring board. Thereby, the 1st radiation which arrives at a signal processing chip can be reduced.

  Further, in the radiation detector, the first and second radiation detection elements have a plurality of signal output electrodes for outputting an electrical signal from the radiation detection elements, and the plurality of signal output electrodes are the first and first electrodes. The two radiation detection elements may be arranged along one side on the signal processing chip side. This eliminates the need for a signal wiring for transmitting an electrical signal from the first and second radiation detection elements to the signal processing chip, so that the second radiation detection element is connected to the second radiation detection element. It is possible to avoid the incidence of the radiation of 2 from being disturbed by the signal wiring.

  According to the radiation detector of the present invention, the structure can be simplified to reduce the number of steps, and a radiation image with good image quality can be detected.

It is a perspective view which shows the external appearance of the radiation detector which concerns on one Embodiment of this invention. FIG. 2 is an exploded perspective view of the radiation detector shown in FIG. 1. It is a sectional side view along the III-III line of the radiation detector shown by FIG. (A) It is a figure which shows an example of electrode arrangement | positioning in a photon detection element. (B) It is a figure which shows arrangement | positioning of the land pattern of a wiring board corresponding to the electrode arrangement | positioning shown by (a), and the shape of signal wiring. (C) It is a figure which shows another example of the electrode arrangement | positioning in a photon detection element. (D) It is a figure which shows arrangement | positioning of the land pattern of a wiring board corresponding to the electrode arrangement | positioning shown by (c), and the shape of signal wiring. It is a perspective view which shows the external appearance of the radiation detector which concerns on 2nd Embodiment of this invention. It is a sectional side view which shows the structure of the radiation detector which concerns on 3rd Embodiment of this invention. It is a sectional side view which shows an example of the structure of a radiation detector.

  Embodiments of a radiation detector according to the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a perspective view showing an appearance of a radiation detector 10A according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the radiation detector 10A shown in FIG. FIG. 3 is a side sectional view taken along line III-III of the radiation detector 10A shown in FIG. In FIG. 3, the main part of the cross section of the radiation detector 10 </ b> A is enlarged for easy understanding.

  The radiation detector 10A is a device that detects the first radiation X1 shown in FIG. 3 and the second radiation X2 having higher energy than the first radiation X1. Note that the first radiation X1 is, for example, soft X-rays, and the second radiation X2 is, for example, hard X-rays. As shown in FIGS. 1 to 3, the radiation detector 10 </ b> A of the present embodiment includes a wiring board 20, a first radiation detection element 30, a second radiation detection element 40, and signal processing chips 51 and 52. And a connector 53.

  The wiring board 20 is a circuit board having a metal wiring pattern for transmitting electrical signals output from the first and second radiation detection elements 30 and 40, and is mainly composed of a resin material such as glass epoxy resin. Has been. The wiring board 20 of the present embodiment has a substantially rectangular planar shape having a longitudinal direction and a short direction perpendicular to the longitudinal direction. The wiring board 20 has a plate surface 20a and a plate surface 20b opposite to the plate surface 20a.

  The first radiation detection element 30 is an element for detecting the first radiation X1 incident from the one plate surface 20a side of the wiring board 20. The first radiation detection element 30 includes a plurality of light detection elements 31 arranged along a predetermined direction A (the short direction of the wiring board 20 in the present embodiment), and a scintillator disposed on the plurality of light detection elements 31. 32. The scintillator 32 converts the first radiation X1 into light. The plurality of photodetecting elements 31 detect light emitted from the scintillator 32 and output an electrical signal corresponding to the amount of light. The plurality of light detecting elements 31 are mounted (bump mounted) on the land pattern 21 included in the wiring pattern formed on one plate surface 20 a of the wiring substrate 20 via the bump electrode 33. The plurality of light detection elements 31 are realized by, for example, a photodiode array.

  The second radiation detection element 40 is an element for detecting the second radiation X <b> 2 incident from the one plate surface 20 a side of the wiring board 20. The second radiation detection element 40 includes a plurality of light detection elements 41 arranged along the predetermined direction A, and a scintillator 42 disposed on the plurality of light detection elements 41. The scintillator 42 converts the second radiation X2 into light. The plurality of light detection elements 41 detect the light emitted from the scintillator 42 and output an electrical signal corresponding to the amount of light. The plurality of light detection elements 41 are mounted (bump mounted) on the land pattern 22 included in the wiring pattern formed on the other plate surface 20 b of the wiring substrate 20 via the bump electrodes 43. The plurality of photodetecting elements 41 are realized by, for example, a photodiode array.

  The signal processing chips 51 and 52 are electrically connected to the light detection elements 31 and 41 via the wiring pattern of the wiring board 20. The signal processing chip 51 is, for example, an ASIC (Application Specific Integrated Circuit). The signal processing chip 52 is, for example, a controller IC. The signal processing chips 51 and 52 control the driving of the photodetecting elements 31 and 41 and also input the electric signal output from the photodetecting elements 31 and 41, and the detection results of the radiation X1 and X2 based on the electric signal Generate data about. The signal processing chip 51 of the present embodiment is mounted (bump mounted) on the land pattern 23 included in the wiring pattern formed on one plate surface 20a of the wiring substrate 20 via the bump electrode 54. Similarly, the signal processing chip 52 is mounted (bump mounted) on the land pattern 24 included in the wiring pattern formed on one plate surface 20a of the wiring substrate 20 via the bump electrode 55.

  As shown in FIG. 3, the wiring board 20 of this embodiment includes a plurality of metal layers 25. The metal layer 25 is a thin film made of a metal such as copper, for example, and serves as a filter that blocks the first radiation X1 and selectively transmits the second radiation X2. The plurality of metal layers 25 are provided inside the wiring board 20 (that is, an area between one plate surface 20 a and the other plate surface 20 b), and are stacked in the thickness direction of the wiring substrate 20. . Further, the plurality of metal layers 25 are separated from each other by a predetermined interval. Between the metal layers 25 adjacent to each other, a resin material (for example, glass epoxy resin) which is a main material of the wiring board 20 is interposed.

  The plurality of metal layers 25 are disposed in a region located between the first radiation detection element 30 and the second radiation detection element 40. More specifically, the plurality of metal layers 25 project the radiation detection elements 30 and 40 onto the wiring board 20 with projection lines along the incident directions of the radiation X1 and X2 (that is, the thickness direction of the wiring board 20). It is provided in the region including the region obtained in this way. In other words, the plurality of metal layers 25 are provided in a region including the radiation detection elements 30 and 40 when viewing the wiring board 20 from the incident direction of the radiations X1 and X2. More preferably, the area occupied by the plurality of metal layers 25 in the wiring board 20 is sufficiently wider than the projection area of the radiation detection elements 30 and 40 onto the wiring board 20 and extends outside the projection area.

  In addition, the wiring board 20 of the present embodiment further includes a through hole 26. The through hole 26 is a wiring element extending in the thickness direction of the wiring board 20, and is provided through the wiring board 20 from the plate surface 20 a to the plate surface 20 b, for example. The through hole 26 constitutes a part of the reference potential line (ground wiring) of the signal processing chips 51 and 52, for example. The plurality of metal layers 25 are preferably connected (short-circuited) to the reference potential lines of the signal processing chips 51 and 52 through the through holes 26.

  Here, the electrode arrangement of the light detection elements 31 and 41 will be described. The photodetecting elements 31 and 41 have a plurality of electrodes, and these electrodes are coupled to the plurality of land patterns 21 and 22 via the bumps 33 and 43 shown in FIG. These electrodes include a signal output electrode (typically an anode) for outputting an electrical signal from the photodetecting element 31 and a bias supply electrode (typically for supplying a bias voltage to the photodetecting element 31). Cathode), and electrodes that are neither of these.

  FIG. 4A is a diagram illustrating an example of the arrangement of the signal output electrode 35, the bias supply electrode 36, and the other electrodes 37 in the light detection element 31. The photodetecting element 31 shown in the figure has two photodiodes 34, and these photodiodes 34 are connected to two signal output electrodes 35 through wirings 38, respectively. 4A shows the photodetecting element 31, the photodetecting element 41 has the same configuration.

  4B shows the arrangement of land patterns 21 on the wiring board 20 corresponding to the electrode arrangement shown in FIG. 4A (land pattern 21a for signal output, land pattern 21b for bias supply, and others). The land pattern 21c) and the shape of the signal wiring 29 are shown. The signal wiring 29 is a part of the wiring pattern of the wiring board 20, and electrically connects the signal output land pattern 21 a and the signal processing chips 51 and 52.

  In this example, the plurality of signal output electrodes 35 of the light detection element 31 are on the signal processing chip 51, 52 side of a pair of sides extending in the predetermined direction A (short direction of the wiring board 20) in the light detection element 31. Are arranged along one side. Therefore, as shown in FIG. 4B, the signal wiring 29 can be extended to the signal processing chips 51 and 52 without traversing the light detection element 31.

  FIG. 4C is a diagram illustrating another example of the arrangement of the signal output electrode 35, the bias supply electrode 36, and the other electrodes 37 in the light detection element 31. 4C shows the light detection element 31, the light detection element 41 has the same configuration. 4D shows an arrangement of land patterns 21 on the wiring board 20 corresponding to the electrode arrangement shown in FIG. 4C (land pattern 21a for signal output, land pattern 21b for bias supply, and others). The land pattern 21c) and the shape of the signal wiring 29 are shown.

  In this example, the plurality of signal output electrodes 35 of the light detection element 31 are arranged so as to alternately follow a pair of sides extending in the predetermined direction A in the light detection element 31 (in a staggered pattern). Therefore, as illustrated in FIG. 4D, the signal wiring 29 extends across the signal processing chips 51 and 52, and thus crosses the light detection element 31.

  Comparing the example of the electrode arrangement of the photodetecting element 31 shown in FIG. 4A with the example of the electrode arrangement of the photodetecting element 31 shown in FIG. However, the electrode arrangement of FIG. 4A is preferable in that it does not have to cross the light detection element 31. By preventing the signal wiring 29 from crossing the light detection element 31, it is avoided that the second wiring X 2 is incident on the radiation detection element 40 by the signal wiring 29, and the second without being affected by the signal wiring 29. This is because the radiation X2 can be detected.

  On the other hand, from the viewpoint of narrowing the pitch of the plurality of photodetecting elements 31, the electrode arrangement shown in FIG. That is, by arranging the plurality of signal output electrodes 35 in a staggered arrangement, the intervals between the plurality of photodetecting elements 31 can be reduced, and the pitch of the photodiodes 34 in the predetermined direction A can be shortened.

  The effect obtained by the radiation detector 10A having the above configuration will be described. In the radiation detector 10A of the present embodiment, the light detection element 31 of the first radiation detection element 30 is bump-mounted on one plate surface 20a of the wiring board 20, and the light detection of the second radiation detection element 40 is performed. The element 41 is bump-mounted on the other plate surface 20 b of the wiring board 20. As described above, the radiation detection elements 30 and 40 are bump-mounted on the wiring board 20 so that the radiation detection elements 30 and 40 are attached to the wiring board 20 simultaneously with the mounting of the other signal processing chips 51 and 52. Therefore, as compared with the structure shown in FIG. 7, the structure can be simplified, the number of processes can be reduced, and the production cost can be reduced.

  In addition, since the radiation detection elements 30 and 40 are bump-mounted on the wiring substrate 20, the electrical connection can be stably maintained as compared with the structure shown in FIG. Since the mounting position accuracy of 30, 40 is increased, the reliability of the radiation detector 10A can be increased.

  In addition, the light detection elements 31 and 41 of the radiation detection elements 30 and 40 are bump-mounted on the wiring board 20, so that the upper surfaces of the light detection elements 31 and 41 (surfaces opposite to the surfaces facing the wiring board 20). Since it is not necessary to provide an electrode terminal for wire bonding or the like, the scintillators 32 and 42 can be easily mounted.

  In the radiation detector 10 </ b> A, a metal layer 25 as a filter that selectively transmits the second radiation X <b> 2 is provided inside the wiring board 20. Since such a structure is preferably realized by the interlayer wiring layer of the wiring board 20, the structure can be simplified and the number of processes can be further reduced without adopting a special structure for providing a filter. Therefore, according to the radiation detector 10 </ b> A of the present embodiment, it is possible to significantly reduce the production cost in addition to the effects described above. The number of metal layers 25 is the same as or smaller than the number of layers of the wiring board 20 (for example, 8 to 14 layers) and is arbitrarily set.

  For example, in the X-ray imaging apparatus described in Patent Document 1, a filter for selectively passing high-energy X-rays is arranged on one surface of the wiring board along with the radiation detection element for low-energy X-rays. Are arranged. According to the radiation detector 10A of the present embodiment, the degree of freedom of arrangement of the filter and the radiation detection element can be increased as compared with such a configuration. Further, in such a configuration of Patent Document 1, the filter is separated from the radiation detection element for high energy X-rays by the thickness of the wiring board, and the image quality is deteriorated due to scattering of high energy X-rays. On the other hand, according to the radiation detector 10A of the present embodiment, the filter can be brought closer to the second radiation detection element 40, and a radiation image with good image quality can be detected.

  Moreover, in this radiation detector 10A, since the space | interval of the 1st radiation detection element 30 and the 2nd radiation detection element 40 can be prescribed | regulated only by the thickness of the wiring board 20, compared with the structure which provides a filter separately, These intervals can be shortened. Accordingly, it is possible to reduce the deviation between the image of the radiation X1 and the image of the radiation X2 due to the inclination of the incident angle of the radiation X1 and X2.

  Further, as in the present embodiment, it is preferable that the plurality of metal layers 25 are stacked in the thickness direction of the wiring board 20 and the plurality of metal layers 25 are separated from each other. Thereby, since the total thickness of the metal layer 25 can be made thicker, the effect | action as a filter which selectively permeate | transmits the 2nd radiation X2 can be show | played more effectively. In addition, such a structure can be easily realized by providing a plurality of interlayer wiring layers of the wiring board 20, so that an increase in the number of processes can be suppressed.

  Further, as in the present embodiment, the metal layer 25 is preferably connected to the reference potential lines of the signal processing chips 51 and 52. If the metal layer 25 is in an electrically floating state, the metal layer 25 may act as an antenna and generate noise. Since the metal layer 25 is connected to the reference potential line as in the present embodiment, the potential of the metal layer 25 can be stabilized and noise added to the electric signal can be reduced.

  In addition, as in the present embodiment, it is preferable that the area occupied by the metal layer 25 when viewed from the incident direction of the radiation X1 and X2 is wider than the projection area of the radiation detection elements 30 and 40 onto the wiring board 20. Thereby, the radiation X1 which goes around the edge of the metal layer 25 and reaches the second radiation detection element 40 can be reduced.

  In the present embodiment, the metal layer 25 is provided over a plurality of layers, but only one metal layer 25 may be provided. Even if it is such a form, the effect mentioned above by this embodiment can be acquired suitably. However, since the plurality of metal layers 25 are stacked apart from each other as in the present embodiment, the thickness of the entire filter portion including the interlayer portions of the plurality of metal layers 25 can be increased. Compared with the case where the metal layer 25 is composed of one layer, the radiation X1 that reaches the second radiation detection element 40 by going around the edge of the metal layer 25 can be further reduced.

(Second Embodiment)
FIG. 5 is a perspective view showing the appearance of the radiation detection apparatus 60 according to the second embodiment of the present invention. This radiation detection device 60 includes a plurality of radiation detectors 10A of the first embodiment. The plurality of radiation detectors 10A are arranged side by side in a predetermined direction A (that is, the short direction of the wiring board 20 and the arrangement direction of the plurality of light detection elements 31 and 41). The adjacent radiation detectors 10 </ b> A are electrically connected to each other when the connectors 53 are connected to each other by the inter-substrate connection cable 61. The radiation detector 10 </ b> A disposed at one end of the radiation detector 60 in the predetermined direction A is electrically connected to the signal processing chips 51 and 52 via the cable 62. With such a configuration, a one-dimensional radiation image extending along the predetermined direction A can be suitably detected.

(Third embodiment)
FIG. 6 is a side sectional view showing a configuration of a radiation detector 10B according to the third exemplary embodiment of the present invention. The differences between the radiation detector 10B of the present embodiment and the radiation detector 10A of the first embodiment (see FIG. 3) are the arrangement of the signal processing chips 51 and 52 and the shape of the metal layer 25.

  In the present embodiment, the signal processing chips 51 and 52 are mounted on the other plate surface 20 b of the wiring board 20. Specifically, the signal processing chip 51 is mounted (bump mounted) on the land pattern 27 included in the wiring pattern formed on the other plate surface 20 b of the wiring substrate 20 via the bump electrode 54. . Similarly, the signal processing chip 52 is mounted (bump mounted) on the land pattern 28 included in the wiring pattern formed on the other plate surface 20 b of the wiring substrate 20 via the bump electrode 55. Thereby, the signal processing chips 51 and 52 are electrically connected to the light detection elements 31 and 41 via the wiring pattern of the wiring substrate 20. The light detection element 31 mounted on one plate surface 20a of the wiring board 20 and the signal processing chips 51 and 52 are connected by a through hole penetrating from the plate surface 20a of the wiring substrate 20 to the plate surface 20b. It is suitably performed.

  In addition to the region located between the first radiation detection element 30 and the second radiation detection element 40, the metal layer 25 of the present embodiment is disposed in the region where the signal processing chips 51 and 52 are mounted. It is arranged over. More specifically, the metal layer 25 wires the radiation detection elements 30 and 40 and the signal processing chips 51 and 52 with projection lines along the incident directions of the radiation X1 and X2 (that is, the thickness direction of the wiring board 20). It is provided in a region including a region obtained by projecting onto the substrate 20. In other words, the metal layer 25 is provided in a region including the radiation detection elements 30 and 40 and the signal processing chips 51 and 52 when viewing the wiring board 20 from the incident direction of the radiations X1 and X2. More preferably, the area occupied by the metal layer 25 in the wiring board 20 is sufficiently wider than the projection area of the radiation detection elements 30 and 40 and the signal processing chips 51 and 52 on the wiring board 20 and extends beyond the projection area. It extends.

  As described above, in this embodiment, the signal processing chips 51 and 52 are mounted on the other plate surface 20 b of the wiring board 20. Thereby, the 1st radiation X1 which reaches | attains the signal processing chips 51 and 52 can be reduced by the metal layer 25 of the wiring board 20, for example. As a means for reducing the first radiation X1 reaching the signal processing chips 51 and 52, in addition to the method using the metal layer 25 of the wiring board 20 as in the present embodiment, for example, the plate surface 20a of the wiring board. Various structures such as providing a radiation shield on the top can be applied.

  The radiation detector according to the present invention is not limited to the above-described embodiment, and various other modifications are possible. For example, in the above embodiment, copper is exemplified as the constituent material of the metal layer 25. However, as the constituent material of the metal layer 25, various materials that selectively transmit the second radiation X2 can be used.

10A, 10B, 100 ... radiation detector, 20 ... wiring board, 21-24, 27, 28 ... land pattern, 25 ... metal layer, 26 ... through hole, 29 ... signal wiring, 30 ... first radiation detection element, DESCRIPTION OF SYMBOLS 31 ... Photodetection element, 32 ... Scintillator, 33 ... Bump electrode, 40 ... 2nd radiation detection element, 41 ... Photodetection element, 42 ... Scintillator, 43 ... Bump electrode, 51, 52 ... Signal processing chip, 53 ... Connector , 101 ... wiring board, A ... predetermined direction, X1 ... first radiation, X2 ... second radiation.

Claims (5)

A first radiation detection element for detecting first radiation;
A second radiation detecting element for detecting a second radiation having higher energy than the first radiation;
A wiring board having a wiring pattern for transmitting electrical signals output from the first and second radiation detection elements;
The first radiation detection element is bump-mounted on the wiring pattern on one side of the wiring board, and the second radiation detection element is on the wiring pattern on the other side of the wiring board. Bump mounted,
A metal layer serving as a filter that selectively transmits the second radiation is provided in a region located between the first radiation detection element and the second radiation detection element inside the wiring board. A radiation detector, characterized in that A plurality of the metal layers are laminated in the thickness direction of the wiring board,
The radiation detector according to claim 1, wherein the plurality of metal layers are separated from each other. A signal processing chip mounted on the wiring board and electrically connected to the first and second radiation detection elements via the wiring pattern;
The radiation detector according to claim 1, wherein the metal layer is connected to a reference potential line of the signal processing chip.   The radiation detector according to claim 3, wherein the signal processing chip is mounted on the other surface of the wiring board. The first and second radiation detection elements have a plurality of signal output electrodes that output the electrical signals from the radiation detection elements,
5. The plurality of signal output electrodes are arranged along one side of the first and second radiation detection elements on the signal processing chip side. 6. The radiation detector according to 1.

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