Radiation detectors and radiation detector arrays

Abstract

To provide a radiation detector having high temporal resolution and high detection sensitivity.SOLUTION: A radiation detector RD1 comprises: a scintillator 1 including end faces 1a and 1b having a rectangular shape viewed from a first direction D1 and facing each other in the first direction D1, and side faces 1c and 1d facing each other in a second direction D2 crossing the first direction D1 and connecting the end faces 1a and 1b; a semiconductor photodetector 10a including a semiconductor substrate 11a disposed to face the side face 1c; a semiconductor photodetector 10b including a semiconductor substrate 11b disposed to face the side face 1d; a wiring member 30a electrically connected to the semiconductor photodetector 10a; and a wiring member 30b electrically connected to the semiconductor photodetector 10b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to radiation detectors and radiation detector arrays. [Background technology]

[0002] A known radiation detector includes a hexahedral scintillator and a semiconductor photodetector element having a semiconductor substrate disposed on the scintillator (see, for example, Patent Document 1). The scintillator generates scintillation light when exposed to radiation. The semiconductor photodetector element detects the generated scintillation light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-83956 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of a first aspect of the present invention is to provide a radiation detector having high temporal resolution and high detection sensitivity, and an object of a second and third aspect of the present invention is to provide a radiation detector array including radiation detectors having high temporal resolution and high detection sensitivity. [Means for solving the problem]

[0005] The present inventors have conducted extensive research into radiation detectors with high time resolution and high detection sensitivity. As a result, the present inventors have newly discovered the following and have arrived at the present invention. Patent Document 1 does not disclose a radiation detector with high time resolution and high detection sensitivity. When radiation is incident on one of a pair of end faces of a scintillator that is long in the first direction, the scintillator reliably absorbs radiation in the high-energy range and generates scintillation light. In a configuration in which a semiconductor photodetector element is disposed on the other end face of the pair of end faces, radiation in the high-energy range is more likely to be reliably absorbed. The semiconductor photodetector element detects scintillation light incident on the other end face. A configuration in which the length of the scintillator in the first direction is greater than the length in the direction intersecting the first direction makes it difficult to achieve high temporal resolution. Compared to the other end faces, the side face connecting the pair of end faces and extending in the first direction is closer to the point where scintillation light is generated. Therefore, a semiconductor photodetector element disposed on the side face extending in the first direction is more likely to detect scintillation light with high temporal resolution. In a radiation detector, it is desirable to dispose the semiconductor photodetector element in a position where simultaneously generated scintillation light can be detected at a short distance. This disposition of the semiconductor photodetector element allows incident radiation to be detected with high temporal resolution. In a configuration in which the semiconductor photodetector element is disposed on a side surface, if the scintillator has multiple side surfaces, it is possible to dispose a semiconductor photodetector element on each of the multiple side surfaces. A radiation detector in which semiconductor photodetector elements are disposed on multiple side surfaces achieves higher detection sensitivity than a radiation detector in which one semiconductor photodetector element is disposed on only one end surface.

[0006] A radiation detector according to a first aspect includes a scintillator having a rectangular shape when viewed from a first direction and having a pair of end faces facing each other in the first direction and a first side face and a second side face facing each other in a second direction intersecting the first direction and connecting the pair of end faces; a first semiconductor photodetector element having a first semiconductor substrate arranged to face the first side face; a second semiconductor photodetector element having a second semiconductor substrate arranged to face the second side face; a first wiring member electrically connected to the first semiconductor photodetector element; and a second wiring member electrically connected to the second semiconductor photodetector element. The length of the scintillator in the first direction is greater than the length of the scintillator in the second direction and the length of the scintillator in a third direction parallel to the first side face. The length of the first side face in the first direction is greater than the width of the first side face in the third direction. The length of the second side face in the first direction is greater than the width of the second side face in the third direction. The first semiconductor substrate has a first portion covered by the first side face and a second portion aligned with the first portion in the first direction and exposed from the first side face. The second semiconductor substrate has a third portion covered by the second side surface and a fourth portion aligned with the third portion in the first direction and exposed from the second side surface. Each of the first and third portions has a photodetection region including a plurality of avalanche photodiodes operating in Geiger mode and a plurality of quenching resistors electrically connected in series to one of the anodes and cathodes of corresponding avalanche photodiodes among the plurality of avalanche photodiodes. Each of the second and fourth portions has a first electrode to which the plurality of quenching resistors are connected in parallel and a second electrode to which the other of the anodes and cathodes of the plurality of avalanche photodiodes are connected in parallel. The first and second wiring members each have a conductor electrically connected to the first electrode and a conductor connected to the second electrode.

[0007] According to the first aspect, the radiation detector includes a scintillator that is long in a first direction, and first and second semiconductor photodetector elements that are arranged on first and second side surfaces of the scintillator, respectively. The first and second semiconductor photodetector elements detect scintillation light that is incident on the first and second side surfaces on which the first and second semiconductor photodetector elements are arranged. The length of the scintillator in the second direction is shorter than the length of the scintillator in the first direction. Therefore, the distance from the generation point of the scintillation light to the first side surface and the distance from the generation point of the scintillation light to the second side surface are short. The time it takes for the scintillation light to reach the first and second semiconductor photodetector elements is short, and the first aspect achieves high time resolution. Because the first aspect includes two semiconductor photodetector elements, the first and second semiconductor photodetector elements, it also achieves higher detection sensitivity than a radiation detector that includes a single semiconductor photodetector element arranged on one side surface of the scintillator.

[0008] In the first aspect, the photodetection region of the first semiconductor substrate may have a contour shape corresponding to the contour shape of the first side surface when viewed from the second direction. The photodetection region of the second semiconductor substrate may have a contour shape corresponding to the contour shape of the second side surface when viewed from the second direction. In a configuration in which the photodetection region has a contour shape corresponding to the contour shapes of the first and second side surfaces, the photodetection region does not need to be located in a portion of the first semiconductor substrate that cannot receive scintillation light, thereby suppressing increases in dark count and capacitance in the photodetection region of the first semiconductor substrate. The photodetection region does not need to be located in a portion of the second semiconductor substrate that cannot receive scintillation light, thereby suppressing increases in dark count and capacitance in the photodetection region of the second semiconductor substrate. Detection errors for scintillation light are reduced. Therefore, this configuration reliably improves the time resolution and detection sensitivity of the first and second semiconductor photodetecting elements.

[0009] The first aspect may further include a reinforcing member disposed between the second portion and the fourth portion. The reinforcing member may cover the second portion and the fourth portion and connect the second portion and the fourth portion. In a configuration including a reinforcing body disposed between the second part and the fourth part, the mechanical strength of the second part and the fourth part is improved by the reinforcing body disposed between the second part and the fourth part.

[0010] In the first aspect, the first semiconductor substrate may have a first surface facing the scintillator in the second direction and a second surface facing the first surface in the second direction. The second semiconductor substrate may have a third surface facing the scintillator in the second direction and a fourth surface facing the third surface in the second direction. The second and fourth surfaces may be polished surfaces. In a configuration in which the second surface and the fourth surface are polished surfaces, the first and second semiconductor substrates can be thinned, and the size of the radiation detector can be reduced in the thickness direction of the first and second semiconductor substrates.

[0011] The first aspect may include a first substrate having a fifth surface and a sixth surface facing each other in the second direction, with a first semiconductor substrate positioned between the fifth surface and the scintillator; a second substrate having a seventh surface and an eighth surface facing each other in the second direction, with a second semiconductor substrate positioned between the seventh surface and the scintillator; and a first terminal and a second terminal positioned on the fifth surface, and a third terminal and a fourth terminal positioned on the seventh surface. The first substrate may have a fifth portion covered by the first semiconductor substrate and a sixth portion aligned with the fifth portion in the first direction and exposed from the first semiconductor substrate. The second substrate may have a seventh portion covered by the second semiconductor substrate and an eighth portion aligned with the seventh portion in the first direction and exposed from the second semiconductor substrate. The first terminal may be located on the sixth portion and electrically connected to a first electrode positioned on the second portion via a first wire. The second terminal may be located on the sixth portion and electrically connected to a second electrode positioned on the second portion via a second wire. A third terminal may be located on the eighth portion and electrically connected to the first electrode disposed on the fourth portion through a third wire, and a fourth terminal may be located on the eighth portion and electrically connected to the second electrode disposed on the fourth portion through a fourth wire. The configuration including the first and second bases improves the mechanical strength of the radiation detector, and therefore this configuration reliably realizes a radiation detector with improved mechanical strength.

[0012] The first aspect may include a first coating body arranged so that the first semiconductor substrate is located between the first coating body and the scintillator, and a second coating body arranged so that the second semiconductor substrate is located between the first coating body and the scintillator. The first coating body and the second coating body may include at least one of an optical reflector and an electrical insulator. For example, in a configuration in which the first coating and the second coating include a light reflector, the light reflection characteristics of the scintillation light are improved. For example, in a configuration in which the first coating and the second coating include an electrical insulator, the electrical insulation between adjacent radiation detectors is improved.

[0013] In the first aspect, the first wiring member may be disposed on the same side as the scintillator with respect to the first semiconductor substrate, and the second wiring member may be disposed on the same side as the scintillator with respect to the second semiconductor substrate. In a configuration in which the first wiring member is disposed on the same side of the first semiconductor substrate as the scintillator, for example, there is no need to prepare a new substrate for connecting the first wiring member to the first and second electrodes by die bonding. In a configuration in which the second wiring member is disposed on the same side of the second semiconductor substrate as the scintillator, for example, there is no need to prepare a new substrate for connecting the second wiring member to the first and second electrodes by die bonding. Therefore, this configuration more reliably simplifies the configuration of the radiation detector.

[0014] In the first aspect, the first wiring member, the second wiring member, the first semiconductor substrate, and the second semiconductor substrate may be flexible. The flexibility of the first wiring member may be greater than the flexibility of the first semiconductor substrate. The flexibility of the second wiring member may be greater than the flexibility of the second semiconductor substrate. In a configuration in which the flexibility of the first wiring member is greater than the flexibility of the first semiconductor substrate, vibrations are less likely to be transmitted from the first wiring member to the first semiconductor substrate. Forces are less likely to be applied to the first semiconductor substrate from the first wiring member, and the first semiconductor substrate is less likely to be physically damaged. In a configuration in which the flexibility of the second wiring member is greater than the flexibility of the second semiconductor substrate, vibrations are less likely to be transmitted from the second wiring member to the second semiconductor substrate. Forces are less likely to be applied to the second semiconductor substrate from the second wiring member, and the second semiconductor substrate is less likely to be physically damaged. Therefore, this configuration reliably maintains the mechanical strength of the radiation detector.

[0015] A radiation detector array according to a second aspect is a radiation detector array including a plurality of radiation detectors arranged one-dimensionally, the plurality of radiation detectors being the radiation detectors described above. The scintillator has a pair of third side surfaces connecting the pair of end surfaces and connecting the first side surface and the second side surface. Any two adjacent radiation detectors among the plurality of radiation detectors are arranged side by side such that the third side surface of the scintillator included in one radiation detector faces the third side surface of the scintillator included in the other radiation detector.

[0016] According to the second aspect, a radiation detector array is realized in which radiation detectors having high time resolution and high detection sensitivity are arranged one-dimensionally.

[0017] In the second aspect, the first semiconductor photodetector elements arranged in a line may be integrally formed with one another, and the second semiconductor photodetector elements arranged in a line may be integrally formed with one another. In a configuration in which the first and second semiconductor photodetector elements arranged in one dimension are integrally formed with each other, the mechanical strength of the radiation detector array in which a plurality of radiation detectors are arranged in one dimension is improved.

[0018] In the second aspect, a radiation detector array may include a plurality of radiation detectors arranged two-dimensionally in a matrix, and a plurality of the radiation detectors arranged in the row direction among the plurality of radiation detectors may be the radiation detector array. Any two of the plurality of radiation detectors adjacent to each other in the column direction among the plurality of radiation detectors may be arranged such that either the first semiconductor photodetector element or the second semiconductor photodetector element included in one radiation detector faces either the first semiconductor photodetector element or the second semiconductor photodetector element included in the other radiation detector. In a configuration in which a plurality of radiation detectors are two-dimensionally arranged in a matrix, a radiation detector array in which radiation detectors having high time resolution and high detection sensitivity are two-dimensionally arranged in a matrix is realized by arranging one-dimensionally arranged radiation detector arrays in a column direction.

[0019] A radiation detector array according to a third aspect includes a plurality of radiation detectors arranged in one dimension, the plurality of radiation detectors being the radiation detectors described above. The scintillator has a pair of third side surfaces connecting the pair of end surfaces and connecting the first side surface and the second side surface. Any two adjacent radiation detectors among the plurality of radiation detectors are arranged so that the third side surface of the scintillator included in one radiation detector faces either the first semiconductor photodetector element or the second semiconductor photodetector element included in the other radiation detector.

[0020] According to the third aspect, a radiation detector array is realized in which radiation detectors having high time resolution and high detection sensitivity are arranged one-dimensionally.

[0021] In the third aspect, a radiation detector array includes a plurality of radiation detectors arranged two-dimensionally in a matrix, and a plurality of the radiation detectors arranged in the row direction among the plurality of radiation detectors are the radiation detector array, and any two of the plurality of radiation detectors adjacent to each other in the column direction may be arranged such that the third side surface of the scintillator included in one radiation detector and either the first semiconductor photodetector element or the second semiconductor photodetector element included in the other radiation detector face each other in the column direction. In a configuration in which a plurality of radiation detectors are two-dimensionally arranged in a matrix, a radiation detector array is realized in which radiation detectors having high time resolution and high detection sensitivity are two-dimensionally arranged in a matrix. Since the third side surface and either the first semiconductor photodetector element or the second semiconductor photodetector element included in the other radiation detector face each other in the column direction, the plurality of radiation detectors can be two-dimensionally arranged in a smaller space than in a configuration in which the first and second semiconductor photodetector elements face each other. [Effects of the Invention]

[0022] A first aspect of the present invention provides a radiation detector having high temporal resolution and high detection sensitivity. Second and third aspects of the present invention provide a radiation detector array including radiation detectors having high temporal resolution and high detection sensitivity. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a radiation detector according to the first embodiment. [Figure 2] FIG. 2 is a perspective view showing the radiation detector according to the first embodiment. [Figure 3] FIG. 3 is a plan view showing the first semiconductor photodetector element. [Figure 4] FIG. 4 is a plan view showing the second semiconductor photodetector element. [Figure 5] FIG. 5 is a diagram showing an equivalent circuit of the photodetection region. [Figure 6] FIG. 6 is a side view showing the radiation detector according to the first embodiment. [Figure 7] FIG. 7 is a side view showing the radiation detector according to the first embodiment. [Figure 8] FIG. 8 is a side view showing the radiation detector according to the first embodiment. [Figure 9] FIG. 9 is a perspective view showing the radiation detector according to the first embodiment. [Figure 10] FIG. 10 is a perspective view showing the radiation detector according to the first embodiment. [Figure 11] FIG. 11 is a diagram showing the path of part of the scintillation light. [Figure 12] FIG. 12 is a perspective view showing a radiation detector array according to the second embodiment. [Figure 13] FIG. 13 is a perspective view showing a radiation detector array according to the second embodiment. [Figure 14] FIG. 14 is a perspective view showing a radiation detector array according to the third embodiment. [Figure 15] FIG. 15 is a perspective view showing a radiation detector array according to the third embodiment. [Figure 16] FIG. 16 is a flow chart showing a method for manufacturing a radiation detector. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will be described in detail with reference to the accompanying drawings. In the description, the same elements or elements having the same functions will be denoted by the same reference numerals, and redundant description will be omitted.

[0025] (First embodiment) The configuration of the radiation detector RD1 according to the first embodiment will be described with reference to FIGS. 1 to 11. FIGS. 1 and 2 are perspective views showing the radiation detector according to the first embodiment. FIG. 3 is a plan view showing a first semiconductor photodetector element. FIG. 4 is a plan view showing a second semiconductor photodetector element. FIG. 5 is a diagram showing an equivalent circuit of the photodetection region. FIGS. 6 to 8 are side views showing the radiation detector according to the first embodiment. FIGS. 9 and 10 are perspective views showing the radiation detector according to the first embodiment. FIG. 11 is a diagram showing the path of part of the scintillation light. In FIGS. 1 and 9, part of the second semiconductor photodetector element is omitted for the sake of explanation. In FIGS. 2 and 10, part of the first semiconductor photodetector element is omitted for the sake of explanation. In FIGS. 9 and 10, the reinforcing body is indicated by a two-dot chain line.

[0026] As shown in FIGS. 1 and 2, the radiation detector RD1 includes a scintillator 1, semiconductor photodetecting elements 10a and 10b, and wiring members 30a and 30b. The scintillator 1 generates scintillation light (fluorescence) upon receiving incident radiation. The semiconductor photodetecting elements 10a and 10b detect the scintillation light generated by the scintillator 1. The semiconductor photodetecting element 10a has a semiconductor substrate 11a and is electrically connected to the wiring member 30a. The semiconductor photodetecting element 10b has a semiconductor substrate 11b and is electrically connected to the wiring member 30b. For example, when the semiconductor photodetecting element 10a constitutes a first semiconductor photodetecting element, the semiconductor photodetecting element 10b constitutes a second semiconductor photodetecting element. For example, when the wiring member 30a constitutes a first wiring member, the wiring member 30b constitutes a second wiring member. For example, when the semiconductor substrate 11a constitutes a first semiconductor substrate, the semiconductor substrate 11b constitutes a second semiconductor substrate.

[0027] The scintillator 1 has a pair of end faces 1a, 1b facing each other, a pair of side faces 1c, 1d facing each other, and a pair of side faces 1e, 1f facing each other. The end faces 1a, 1b, the side faces 1c, 1d, and the side faces 1e, 1f constitute the outer surface of the scintillator 1. The end faces 1a, 1b face each other in a first direction D1. The end faces 1a, 1b define both ends of the scintillator 1 in the first direction D1. The side faces 1c, 1d face each other in a second direction D2 intersecting the first direction D1 and connect the pair of end faces 1a, 1b. In this embodiment, the second direction D2 coincides with the direction perpendicular to the side face 1c. The side faces 1c, 1d define both ends of the scintillator 1 in the second direction D2. The side faces 1e, 1f connect the end faces 1a, 1b and also connect the side faces 1c and 1d. The side surfaces 1e and 1f face each other in a third direction D3 that intersects the first direction D1 and the second direction D2. The third direction D3 coincides with a direction parallel to the side surface 1c. In this embodiment, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to each other. The side surfaces 1e and 1f define both ends of the scintillator 1 in the third direction D3. For example, when the side surface 1c constitutes a first side surface, the side surface 1d constitutes a second side surface, and the side surfaces 1e and 1f constitute a pair of third side surfaces.

[0028] End face 1a and end face 1b extend in the second direction D2 to connect side face 1c and side face 1d. End face 1a and end face 1b extend in the third direction D3 to connect side face 1e and side face 1f. Side face 1c and side face 1d extend in the first direction D1 to connect end face 1a and end face 1b. Side face 1c and side face 1d extend in the third direction D3 to connect side face 1e and side face 1f. Side face 1e and side face 1f extend in the first direction D1 to connect end face 1a and end face 1b. Side face 1e and side face 1f extend in the second direction D2 to connect side face 1c and side face 1d. Side face 1e and side face 1f are adjacent to side face 1c.

[0029] The length of the scintillator 1 in the first direction D1 is greater than the length of the scintillator 1 in the second direction D2. The length of the scintillator 1 in the first direction D1 is greater than the length of the scintillator 1 in the third direction D3. The first direction D1 is the longitudinal direction of the scintillator 1. The length of the side surface 1c in the first direction D1 is greater than the width of the side surface 1c in the third direction D3. The length of the side surface 1d in the first direction D1 is greater than the width of the side surface 1d in the third direction D3.

[0030] The end faces 1a, 1b, the side faces 1c, 1d, and the side faces 1e, 1f have a rectangular shape when viewed from a direction perpendicular to these faces. In this embodiment, the scintillator 1 has a rectangular shape when viewed from the first direction D1, and also has a rectangular shape when viewed from the second direction D2 and the third direction D3. The scintillator 1 has, for example, a rectangular parallelepiped shape. The length of the scintillator 1 in the first direction D1 is, for example, about 20 mm. The length of the scintillator 1 in the second direction D2 is, for example, about 4 mm. The length of the scintillator 1 in the third direction D3 is, for example, about 4 mm. In this specification, the term "rectangular shape" includes, for example, a shape with chamfered corners and a shape with rounded corners. In this specification, the term "rectangular shape" includes a rectangular parallelepiped shape with chamfered corners and ridges, and a rectangular parallelepiped shape with rounded corners and ridges.

[0031] The scintillator 1 includes, for example, a crystalline scintillator, a ceramic scintillator, or a plastic scintillator. Crystalline scintillators include, for example, CsI, NaI, LaBr3, cerium-doped lutetium yttrium orthosilicate (LYSO(Ce)), gadolinium aluminum gallium garnet (GAGG), lutetium oxyorthosilicate (LSO), bismuth germanate (BGO), or ruthenium aluminum garnet (LuAG). Ceramic scintillators include, for example, a sintered body of an inorganic phosphor. Plastic scintillators include, for example, polyethylene terephthalate (PET).

[0032] The semiconductor substrate 11a is disposed so as to face the side surface 1c. The semiconductor substrate 11b is disposed so as to face the side surface 1d. The semiconductor substrates 11a and 11b contain, for example, Si. Except for being disposed on the side surface 1d, the semiconductor substrate 11b has the same form and exhibits the same function as, for example, the semiconductor substrate 11a disposed on the side surface 1c. The semiconductor substrate 11a is disposed on the side surface 1c, for example, via an adhesive. The semiconductor substrate 11b is disposed on the side surface 1d, for example, via an adhesive.

[0033] As shown in FIG. 3, the semiconductor substrate 11a has a portion 21a and a portion 22a. In this embodiment, the portion 21a is covered by the side surface 1c. The portion 22a is aligned with the portion 21a in the first direction D1 and is exposed from the side surface 1c. As shown in FIG. 4, the semiconductor substrate 11b has a portion 21b and a portion 22b. In this embodiment, the portion 21b is covered by the side surface 1d. The portion 22b is aligned with the portion 21b in the first direction D1 and is exposed from the side surface 1d. For example, when the portion 21a constitutes the first portion, the portion 22a constitutes the second portion. For example, when the portion 21b constitutes the third portion, the portion 22b constitutes the fourth portion.

[0034] A photodetection region 23 is arranged in each of the portions 21a and 21b. The photodetection region 23 includes a plurality of avalanche photodiodes 12 and a plurality of quenching resistors 13. The avalanche photodiodes 12 receive scintillation light and generate photoelectrons through photoelectric conversion. Conductive wires 14a and 14b are arranged in each of the portions 21a and 21b, and the conductive wire 14a forms a wiring pattern for signal readout that is patterned, for example, in a grid shape when viewed from the second direction D2. Each grid of the conductive wire 14a surrounds one photodetector 15. One photodetector 15 is composed of one avalanche photodiode 12 and one quenching resistor 13 electrically connected in series with the corresponding avalanche photodiode 12. A plurality of photodetector units 15 are arranged in each of the portions 21a and 21b, and the photodetector units 15 are arranged, for example, two-dimensionally in a matrix shape. Each of the photodetection regions 23 may include one avalanche photodiode 12 and one quenching resistor 13 .

[0035] 5, the multiple quenching resistors 13 are electrically connected in series with one of the anodes and cathodes of the corresponding avalanche photodiodes 12 among the multiple avalanche photodiodes 12. The avalanche photodiodes 12 have contact electrodes 16 electrically connected to one of the anodes and cathodes, and one end of the quenching resistor 13 is electrically connected in series with the contact electrode 16. The other end of the quenching resistor 13 is electrically connected in series with a conductor 14a that forms a wiring pattern. A conductor 14b electrically connects the other of the anodes and cathodes of the multiple avalanche photodiodes 12 in parallel.

[0036] The electrical resistivity of the quenching resistor 13 is greater than the electrical resistivity of the electrode 17 and the electrode 18. The quenching resistor 13 includes, for example, polysilicon. The material of the quenching resistor 13 may include, for example, SiCr, NiCr, or FeCr. The quenching resistor 13 is formed by, for example, a chemical vapor deposition (CVD) method or a sputtering method. For example, when the electrode 17 constitutes a first electrode, the electrode 18 constitutes a second electrode.

[0037] As shown in FIGS. 3 and 4 , an electrode 17 and an electrode 18 are disposed on the portion 22a and the portion 22b, respectively. A plurality of quenching resistors 13 are electrically connected in parallel to the electrode 17 via a conductor 14a. The plurality of quenching resistors 13 are electrically connected in series to one of the anodes and the cathodes of corresponding ones of the plurality of avalanche photodiodes 12. The other of the anodes and the cathodes of the plurality of avalanche photodiodes 12 are electrically connected in parallel to the electrode 18 via a conductor 14b. The electrodes 17 and 18 include, for example, aluminum or an aluminum composite (AlSi, AlCu, AlSiCu, etc.). The electrodes 17 and 18 are formed by, for example, a plating method, a vapor deposition method, or a sputtering method.

[0038] In this embodiment, the multiple quenching resistors 13 are electrically connected in series with the anodes of the corresponding avalanche photodiodes 12 among the multiple avalanche photodiodes 12, for example. In this case, the cathodes of the multiple avalanche photodiodes 12 are electrically connected in parallel to the electrode 18. The multiple quenching resistors 13 may also be electrically connected in series with the cathodes of the corresponding avalanche photodiodes 12 among the multiple avalanche photodiodes 12. In this case, the anodes of the multiple avalanche photodiodes 12 are electrically connected in parallel to the electrode 18.

[0039] Each avalanche photodiode 12 operates in Geiger mode. In Geiger mode, a reverse voltage (reverse bias voltage) greater than the breakdown voltage of the avalanche photodiode 12 is applied to the avalanche photodiode 12. For example, a potential V1 is applied to the anode of the avalanche photodiode 12, and a potential V2 that is positive with respect to the potential V1 is applied to the cathode of the avalanche photodiode 12. The polarities of these potentials are relative, and for example, one of the potentials may be the ground potential. The photodetector units 15 are connected in parallel.

[0040] Each avalanche photodiode 12 may be a so-called reach-through type avalanche photodiode or a so-called reverse type avalanche photodiode. The reach-through type avalanche photodiode 12 is used, for example, when the scintillation light is long-wavelength light. The reverse type avalanche photodiode 12 is used, for example, when the scintillation light is short-wavelength light. These reach-through type or reverse type avalanche photodiodes 12 operate in Geiger mode. The radiation detector RD1 may be equipped with an avalanche photodiode 12 that operates in linear mode. The avalanche photodiode 12 that operates in linear mode may also be a so-called reach-through type avalanche photodiode or a so-called reverse type avalanche photodiode.

[0041] The semiconductor substrates 11a and 11b are provided with, for example, conductive wires 14a and 14b, an electrode 17 connected to the conductive wire 14a, and an electrode 18 connected to the conductive wire 14b. The semiconductor substrates 11a and 11b are provided with, for example, an insulating layer 19 on the conductive wires 14a and 14b. In the semiconductor substrate 11a, the insulating layer 19 extends between portions 21a and 22a. In the semiconductor substrate 11b, the insulating layer 19 extends between portions 21b and 22b. In the portions 22a and 22b, the electrode 17 and the conductive wire 14a are insulated from the electrode 18 and the conductive wire 14b by the insulating layer 19. In the portions 21a and 21b, the insulating layer 19 is formed on the multiple photodetectors 15. The insulating layer 19 includes, for example, SiO2 or SiN. The insulating layer 19 is formed by, for example, thermal oxidation, sputtering, or CVD.

[0042] 1, 2, and 6, wiring member 30a is arranged on the same side of semiconductor substrate 11a as scintillator 1. Wiring member 30a, semiconductor substrate 11a, and scintillator 1 are arranged on surface 11c. Wiring member 30b is arranged on the same side of semiconductor substrate 11b as scintillator 1. Wiring member 30b, semiconductor substrate 11b, and scintillator 1 are arranged on surface 11d. Except for being electrically connected to semiconductor substrate 11b, wiring member 30b has the same form and functions as wiring member 30a electrically connected to semiconductor substrate 11a, for example.

[0043] The wiring members 30a and 30b include a conductor 31 and a conductor 32. The conductor 31 is electrically connected to the electrode 17, and the conductor 32 is electrically connected to the electrode 18. The conductor 31 is electrically connected to the electrode 17 via a conductive bump 33. The conductor 32 is connected to the electrode 18 via the conductive bump 33. The conductive bump 33 includes, for example, solder, anisotropic conductive film (ACF), or anisotropic conductive paste (ACP). The solder includes, for example, Sn-Ag-Cu solder. The conductive bump 33 may include, for example, an Au bump, a Ni bump, or a Cu bump.

[0044] In this embodiment, a potential V1 is applied to the anode of the avalanche photodiode 12 via the conductor 31, and a potential V2 is applied to the cathode of the avalanche photodiode 12 via the conductor 32. The potential V1 may be applied to the cathode of the avalanche photodiode 12 via the conductor 32, and the potential V2 may be applied to the anode of the avalanche photodiode 12 via the conductor 31. The conductors 31 and 32 include, for example, Al, Cu, Cu / Ni / Au, or Cu / Ni / Pd / Au. The conductors 31 and 32 are formed by, for example, a sputtering method or a plating method.

[0045] The wiring members 30a and 30b and the semiconductor substrates 11a and 11b are flexible. The flexibility of the wiring members 30a is greater than that of the semiconductor substrate 11a. The flexibility of the wiring members 30b is greater than that of the semiconductor substrate 11b. The flexibility of the wiring members 30a and 30b is, for example, the same. The flexibility of the wiring members 30a and 30b may be different from each other.

[0046] When viewed from the second direction D2, the outline of the light detection region 23 follows the outline of the side surface 1c. Therefore, when viewed from the second direction D2, the multiple edges constituting the outline of the light detection region 23 follow corresponding edges among the multiple edges constituting the outline of the side surface 1c. When viewed from the second direction D2, the outline of the light detection region 23 follows the outline of the side surface 1d. Therefore, when viewed from the second direction D2, the multiple edges constituting the outline of the light detection region 23 follow corresponding edges among the multiple edges constituting the outline of the side surface 1d. When viewed from the second direction D2, the light detection region 23 has an outline shape corresponding to the outline shape of the side surface 1c. The light detection units 15 are arranged so that when viewed from the second direction D2, the light detection region 23 has an outline shape corresponding to the outline shape of the side surface 1c. When viewed from the second direction D2, the light detection region 23 has an outline shape corresponding to the outline shape of the side surface 1d. The photodetectors 15 are arranged so that the photodetection regions 23 have a contour shape corresponding to the contour shape of the side surface 1d when viewed from the second direction D2. In this embodiment, the contour shape of the side surface 1c is rectangular when viewed from the second direction D2, and the photodetection regions 23 have a rectangular contour shape corresponding to the contour shape of the side surface 1c. When viewed from the second direction D2, the contour shape of the side surface 1d is rectangular, and the photodetection regions 23 have a rectangular contour shape corresponding to the contour shape of the side surface 1d.

[0047] As shown in FIGS. 1 and 2, the radiation detector RD1 includes, for example, a reinforcing body 45. The reinforcing body 45 is disposed, for example, between the portion 22a and the portion 22b. In this embodiment, the reinforcing body 45 covers the portion 22a and the portion 22b and connects the portion 22a and the portion 22b. The reinforcing body 45 is in contact with the portion 22a and the portion 22b and the scintillator 1, for example. The reinforcing body 45 has, for example, surfaces 45a, 45b, and 45c exposed from the portion 22a and the portion 22b and the scintillator 1. The surface 45a faces the end face 1b in the first direction D1, for example. The surfaces 45b and 45c face each other in the third direction D3, for example.

[0048] The reinforcing body 45 includes, for example, a resin. The resin of the reinforcing body 45 is filled into a space defined by the portion 22a, the portion 22b, and the scintillator 1. The resin of the reinforcing body 45 includes, for example, a thermosetting resin. The resin of the reinforcing body 45 includes, for example, an epoxy resin, a silicone resin, an acrylic resin, a polyimide resin, a phenolic resin, or a paraxylylene-based polymer.

[0049] In this embodiment, the reinforcing body 45 includes, for example, a block. The block of the reinforcing body 45 has, for example, a shape that fits the space defined by the portions 22a and 22b and the scintillator 1. The block of the reinforcing body 45 has, for example, a recess formed therein so as not to interfere with the wiring members 30a and 30b. The block of the reinforcing body 45 is disposed between the portions 22a and 22b by, for example, an adhesive. The adhesive includes, for example, an epoxy resin, a silicone resin, an acrylic resin, a polyimide resin, or a phenol resin. The blocks of the reinforcing body 45 include, for example, metal. The metal blocks include, for example, Al, titanium alloy, nickel alloy, or stainless steel. The blocks of the reinforcing body 45 include, for example, glass blocks. The glass blocks include, for example, quartz glass or borosilicate glass. The blocks of the reinforcing body 45 include, for example, ceramic blocks. The ceramic blocks include, for example, alumina, silicon nitride, silicon carbide, sapphire, zirconia, cordierite, yttria, aluminum nitride, cermet, mullite, steatite, or forsterite. The blocks of the reinforcing body 45 include, for example, resin blocks. The resin blocks include, for example, epoxy resin, silicone resin, acrylic resin, polyimide resin, phenolic resin, or paraxylylene-based polymer.

[0050] 6, the semiconductor substrate 11a has a surface 11c and a surface 11d that face each other in the second direction D2. The surface 11c faces the scintillator 1 in the second direction D2. The surface 11d faces the surface 11c in the second direction D2. In this embodiment, one of the anode and the cathode of the avalanche photodiode 12 is disposed on the surface 11c, and the other of the anode and the cathode of the avalanche photodiode 12 is disposed on the surface 11d. For example, when the surface 11c constitutes the first surface, the surface 11d constitutes the second surface.

[0051] The semiconductor substrate 11b has a surface 11e and a surface 11f that face each other in the second direction D2. The surface 11e faces the scintillator 1 in the second direction D2. The surface 11f faces the surface 11e in the second direction D2. In this embodiment, one of the anode and the cathode of the avalanche photodiode 12 is disposed on the surface 11e, and the other of the anode and the cathode of the avalanche photodiode 12 is disposed on the surface 11f. For example, when the surface 11e constitutes the third surface, the surface 11f constitutes the fourth surface.

[0052] The surfaces 11d and 11f are, for example, polished surfaces. For example, the surfaces 11d and 11f are polished after the semiconductor substrates 11a and 11b are disposed on the scintillator 1 and the reinforcing body 45 is disposed between the portions 22a and 22b. FIG. 7 is a side view showing the radiation detector RD1 before the surfaces 11d and 11f are polished, and FIG. 8 is a side view showing the radiation detector RD1 after the surfaces 11d and 11f are polished. As shown in FIGS. 7 and 8, in this embodiment, the surface 11d is polished to thin the semiconductor substrate 11a, and the surface 11f is polished to thin the semiconductor substrate 11b.

[0053] The surfaces 11d and 11f are mechanically polished, for example. The surfaces 11d and 11f are mechanically polished by, for example, grinding, lapping, or dry polishing using a polishing foil. The surfaces 11d and 11f may also be mechanochemically polished. The surfaces 11d and 11f are chemically polished by, for example, wet polishing using a CMP slurry. In a configuration in which the surfaces 11d and 11f are polished surfaces, the thickness of the semiconductor substrates 11a and 11b is, for example, 10 to 200 μm. The surface roughness of the polished surfaces is, for example, 0.001 to 200 μm. In this specification, the maximum height (Rz) is used to represent the surface roughness of the surfaces. The maximum height (Rz) is defined in JIS B 0601:2001 (ISO 4287:1997). Before the surfaces 11d and 11f are polished, the thickness of the semiconductor substrates 11a and 11b is, for example, 250 to 1000 μm.

[0054] As shown in FIGS. 1 and 6, the radiation detector RD1 includes, for example, a coating 47a. The coating 47a is arranged so that the semiconductor substrate 11a is located between the coating 47a and the scintillator 1. In this embodiment, the coating 47a is arranged on the surface 11d. The coating 47a is arranged on at least a portion of the surface 11d, and may be arranged on the entire surface 11d. Therefore, the coating 47a may be arranged only in a region of the surface 11d corresponding to the portion 21a, or may be arranged on the entire region of the surface 11d corresponding to the portion 21a and the portion 22a. FIGS. 1 and 6 show an example in which the coating 47a is arranged on the entire region of the surface 11d corresponding to the portion 21a and the portion 22a. The radiation detector RD1 does not necessarily have to include the coating 47a.

[0055] As shown in FIGS. 2 and 6, the radiation detector RD1 includes, for example, a coating 47b. The coating 47b is arranged so that the semiconductor substrate 11b is located between the coating 47b and the scintillator 1. In this embodiment, the coating 47b is arranged on the surface 11f. The coating 47b is arranged on at least a portion of the surface 11f, and may be arranged on the entire surface 11f. Therefore, the coating 47b may be arranged only in a region of the surface 11f corresponding to the portion 21b, or may be arranged on the entire region of the surface 11f corresponding to the portion 21b and the portion 22b. FIGS. 2 and 6 show an example in which the coating 47b is arranged on the entire region of the surface 11f corresponding to the portion 21b and the portion 22b. The radiation detector RD1 does not necessarily have to include the coating 47b. For example, when the coating 47a constitutes a first coating, the coating 47b constitutes a second coating.

[0056] The covering bodies 47a and 47b include, for example, a light reflector 48. The light reflector 48 includes, for example, a film. The film is made of, for example, a metal. The metal includes, for example, Al, Ag, Ti, Pt, Ni, or Au. The light reflector 48 is made of, for example, a metal thin film. The light reflector 48 may include a multilayer optical film or a Teflon (registered trademark) film. The light reflector 48 is formed by, for example, a plating method, a vapor deposition method, or a sputtering method. The light reflector 48 has a thickness of, for example, 0.05 to 100 μm.

[0057] The covering bodies 47a and 47b include, for example, an electrical insulator 49. The electrical insulator 49 includes, for example, a film. The film is made of, for example, an electrical insulating material. The electrical insulating material includes, for example, a silicon compound, an epoxy resin, a silicone resin, an acrylic resin, a polyimide resin, a phenolic resin, or a paraxylylene-based polymer. The electrical insulator 49 is made of, for example, an electrical insulating thin film. The silicon compound includes, for example, SiO2 or SiN. The polymer includes, for example, a paraxylylene-based polymer. The electrical insulator 49 is formed by, for example, chemical vapor deposition (CVD), thermal oxidation, sputtering, evaporation, or potting. The electrical insulator 49 may be formed by, for example, winding an electrical insulating film around the semiconductor substrates 11a and 11b after they are arranged on the scintillator 1. The thickness of the electrical insulator 49 is, for example, 0.05 to 100 μm.

[0058] The coatings 47a and 47b include, for example, an optical reflector 48 and an electrical insulator 49. The coatings 47a and 47b are, for example, a two-layer structure including the optical reflector 48 and the electrical insulator 49. In this case, the optical reflector 48 may be disposed between the semiconductor substrate 11a and the electrical insulator 49, or the electrical insulator 49 may be disposed between the semiconductor substrate 11a and the optical reflector 48. The optical reflector 48 may be disposed between the semiconductor substrate 11b and the electrical insulator 49, or the electrical insulator 49 may be disposed between the semiconductor substrate 11b and the optical reflector 48. In this embodiment, the coatings 47a and 47b include at least one of the optical reflector 48 and the electrical insulator 49. The coatings 47a and 47b are, for example, a single-layer structure including the optical reflector 48 or the electrical insulator 49. The coatings 47a and 47b may, for example, simultaneously have the properties of the optical reflector 48 and the electrical insulator 49. Fig. 6 shows an example in which the electrical insulator 49 is disposed between the semiconductor substrate 11a and the optical reflector 48, and between the semiconductor substrate 11b and the optical reflector 48.

[0059] The covering body 47a is disposed on, for example, the surface 11d. The covering body 47a is disposed on, for example, the entire surface 11d, and may also be disposed on the side surface 11g. The side surface 11g connects the surface 11c and the surface 11d to each other in the second direction D2 and, for example, forms the outer periphery of the covering body 47a when viewed from the second direction D2. The light reflector 48 may be disposed on the entire surface 11d, and the electrical insulator 49 may be disposed on the light reflector 48 disposed on the surface 11d and on the side surface 11g. The covering body 47b is disposed on, for example, the surface 11f. The covering body 47b is disposed on, for example, the entire surface 11f, and may also be disposed on the side surface 11h. The side surface 11h connects the surface 11e and the surface 11f to each other in the second direction D2 and, for example, forms the outer periphery of the covering body 47b when viewed from the second direction D2. The light reflector 48 may be disposed on the entire surface 11f, and the electrical insulator 49 may be disposed on the light reflector 48 disposed on the surface 11f and on the side surface 11h.

[0060] In the present embodiment, in a configuration in which the potential of the anode or cathode of the avalanche photodiode 12 on the surface 11d is ground potential, the electrical insulator 49 may not be arranged on the surface 11d. In a configuration in which the potential of the anode or cathode of the avalanche photodiode 12 on the surface 11d is not ground potential, the electrical insulator 49 may be arranged on the surface 11d. In a configuration in which the potential of the anode or cathode of the avalanche photodiode 12 on the surface 11f is ground potential, the electrical insulator 49 may not be arranged on the surface 11f. In a configuration in which the potential of the anode or cathode of the avalanche photodiode 12 on the surface 11f is not ground potential, the electrical insulator 49 may be arranged on the surface 11f.

[0061] As shown in FIGS. 9 and 10 , the radiation detector RD1 includes, for example, a base body 40a and a base body 40b. The base body 40a has a surface 40c and a surface 40d facing each other in the second direction D2, and is disposed so that the semiconductor substrate 11a is located between the surface 40c and the scintillator 1. The base body 40b has a surface 40e and a surface 40f facing each other in the second direction D2, and is disposed so that the semiconductor substrate 11b is located between the surface 40e and the scintillator 1. The base body 40b has, for example, the same shape and function as the base body 40a. For example, when the base body 40a constitutes the first base body, the base body 40b constitutes the second base body. For example, when the surface 40c constitutes the fifth surface, the surface 40d constitutes the sixth surface. For example, when the surface 40e constitutes the seventh surface, the surface 40f constitutes the eighth surface.

[0062] The base 40a has a portion 51a and a portion 52a. The portion 51a is covered by the semiconductor substrate 11a. The portion 52a is aligned with the portion 51a in the first direction D1 and is exposed from the semiconductor substrate 11a. The base 40b has a portion 51b and a portion 52b. The portion 51b is covered by the semiconductor substrate 11b. The portion 52b is aligned with the portion 51b in the first direction D1 and is exposed from the semiconductor substrate 11b. The base 40b has, for example, the same configuration and function as the base 40a. For example, if the portion 51a constitutes the fifth portion, the portion 52a constitutes the sixth portion. For example, if the portion 51b constitutes the seventh portion, the portion 52b constitutes the eighth portion.

[0063] The radiation detector RD1 includes terminals 41 and 42 arranged on the surface 40c. The terminals 41 and 42 are arranged, for example, on the same side of the semiconductor substrate 11a as the scintillator 1. The terminal 41 is located on the portion 52a and is electrically connected to the electrode 17 arranged on the portion 22a through a wire 43. The terminal 42 is located on the portion 52a and is electrically connected to the electrode 18 arranged on the portion 22a through a wire 44. The wires 43 and 44 are covered and protected, for example, by the resin of the reinforcing body 45. The wiring member 30a is electrically connected to the electrodes 17 and 18 via conductive bumps 46. In the base 40a, for example, if the terminal 41 constitutes a first terminal, the terminal 42 constitutes a second terminal. In the base 40a, for example, if the wire 43 constitutes a first wire, the wire 44 constitutes a second wire. The wires 43 and 44 may be protected, for example, by a block of the reinforcing body 45.

[0064] The radiation detector RD1 includes terminals 41 and 42 arranged on the surface 40e. The terminals 41 and 42 are arranged, for example, on the same side as the scintillator 1 with respect to the semiconductor substrate 11b. The terminal 41 is located on the portion 52b and is electrically connected to the electrode 17 arranged on the portion 22b through a wire 43. The terminal 42 is located on the portion 52b and is electrically connected to the electrode 18 arranged on the portion 22b through a wire 44. The wires 43 and 44 are covered and protected, for example, by the resin of the reinforcing body 45. The wiring member 30b is electrically connected to the electrodes 17 and 18 via conductive bumps 46. In the base 40b, for example, if the terminal 41 constitutes the third terminal, the terminal 42 constitutes the fourth terminal. In the base 40b, for example, if the wire 43 constitutes the third wire, the wire 44 constitutes the fourth wire. In this embodiment, the terminal 41 of the base 40b has the same configuration and function as the terminal 41 of the base 40a, and the terminal 42 of the base 40b has the same configuration and function as the terminal 42 of the base 40a. The radiation detector RD1 does not need to include either the base 40a or the base 40b, or it does not need to include both the base 40a and the base 40b. The wires 43 and 44 may be protected by, for example, a block of a reinforcing member 45.

[0065] The radiation detector RD1 includes, for example, a resin 55. The resin 55 covers, for example, the wire 43 and the wire 44 individually, or both the wire 43 and the wire 44. When the resin 55 covers the wire 43 and the wire 44 individually, the resins 55 may be spaced apart from each other or connected to each other. In this specification, "the resin 55 covers the wire 43" also includes covering the connection point between the terminal 41 and the wire 43 and the connection point between the electrode 17 and the wire 43. Furthermore, "the resin 55 covers the wire 44" also includes covering the connection point between the terminal 42 and the wire 44 and the connection point between the electrode 18 and the wire 44. In this embodiment, the resin of the reinforcing body 45 is disposed between the portion 22a and the portion 22b so as to cover the resin 55. The radiation detector RD1 does not necessarily include the resin 55. FIGS. 9 and 10 show an example in which the radiation detector RD1 includes the resin 55. A block of reinforcement 45 may be placed between portions 22a and 22b to cover resin 55.

[0066] Even in a configuration in which radiation detector RD1 includes a base 40a, for example, a coating 47a is also arranged. The coating 47a is arranged on the surface 40d. In this configuration, the scintillator 1, the semiconductor substrate 11a, the base 40a, and the coating 47a are arranged in this order. Even in a configuration in which radiation detector RD1 includes a base 40b, for example, a coating 47b is also arranged. The coating 47b is arranged on the surface 40f. In this configuration, the scintillator 1, the semiconductor substrate 11b, the base 40b, and the coating 47b are arranged in this order. The radiation detector RD1 does not have to include at least one of the coating 47a and the coating 47b.

[0067] As shown in FIG. 11, the scintillation light includes, for example, light L1 and light L2 incident on the side surface 1c from a scintillation light generation point GP1. Light L1 is incident on the side surface 1c approximately perpendicularly, and light L2 is incident on the side surface 1c at an incident angle EA1. The approximately perpendicular incident angle of light L1 and the incident angle EA1 of light L2 are smaller than the critical angle at the side surface 1c. Light L1 and L2 are incident on the side surface 1c and transmitted through the side surface 1c. Light L1 and L2 are detected by the semiconductor photodetector element 10a arranged on the side surface 1c. The scintillation light includes, for example, light L3 and light L4 incident on the side surface 1d from the generation point GP1. Light L3 is incident on the side surface 1d approximately perpendicularly, and light L4 is incident on the side surface 1d at an incident angle EA2. The incident angle EA2 of the light L4, which is approximately perpendicular to the surface of the substrate 1, is smaller than the critical angle at the surface 1d. The light L3 and L4 are incident on the surface 1d and are transmitted through the surface 1d. The light L3 and L4 are detected by the semiconductor photodetector element 10b disposed on the surface 1d.

[0068] In this embodiment, the semiconductor photodetector elements 10a and 10b are bonded to the scintillator 1 with an adhesive having the same refractive index, and the critical angles at the side surfaces 1c and 1d are equal to each other. The refractive index of the scintillator 1 is, for example, 1.8, and the refractive index of the adhesive is, for example, 1.5. The critical angle of the scintillation light at the side surfaces 1c and 1d is, for example, approximately 56.4 degrees. FIG. 11 shows a partial path of the scintillation light when the scintillator 1 is viewed from the second direction D2. The semiconductor photodetector element 10a can detect light L2 in a region R1 where the angle of incidence EA1 of light L2 at the side surface 1c is smaller than the critical angle at the side surface 1c. The semiconductor photodetector element 10b can detect light L4 in a region R2 where the angle of incidence EA2 of light L4 at the side surface 1d is smaller than the critical angle at the side surface 1d.

[0069] As shown in FIGS. 1, 2, 6, and 11, the radiation detector RD1 includes, for example, a light reflector 56. The light reflector 56 is disposed, for example, on at least one of the end faces 1a, 1b and the side faces 1e, 1f of the scintillator 1. In this embodiment, the light reflector 56 is disposed on all of the end faces 1a, 1b and the side faces 1e, 1f. The light reflector 56 reflects scintillation light incident on the end faces 1a, 1b and the side faces 1e, 1f so that the scintillation light does not exit to the outside of the scintillator 1. The material and thickness of the light reflector 56 are, for example, the same as the material and thickness of the light reflector 48. The light reflector 56 is formed, for example, by the same method as the light reflector 48. The radiation detector RD1 does not necessarily have to include the light reflector 56.

[0070] As described above, the radiation detector RD1 is rectangular when viewed from a first direction D1 and includes a scintillator 1 having a pair of end faces 1a, 1b facing each other in the first direction D1 and side faces 1c and 1d facing each other in a second direction D2 intersecting the first direction D1 and connecting the pair of end faces 1a, 1b; a semiconductor photodetector element 10a having a semiconductor substrate 11a arranged to face side face 1c; a semiconductor photodetector element 10b having a semiconductor substrate 11b arranged to face side face 1d; a wiring member 30a electrically connected to the semiconductor photodetector element 10a; and a wiring member 30b electrically connected to the semiconductor photodetector element 10b. The length of the scintillator 1 in the first direction D1 is greater than the length of the scintillator 1 in the second direction D2 and the length of the scintillator 1 in a third direction D3 parallel to the side face 1c. The length of the side face 1c in the first direction D1 is greater than the width of the side face 1c in the third direction D3. The length of the side surface 1d in the first direction D1 is greater than the width of the side surface 1d in the third direction D3. The semiconductor substrate 11a has a portion 21a covered by the side surface 1c and a portion 22a aligned with the portion 21a in the first direction D1 and exposed from the side surface 1c. The semiconductor substrate 11b has a portion 21b covered by the side surface 1d and a portion 22b aligned with the portion 21b in the first direction D1 and exposed from the side surface 1d. Arranged in each of the portions 21a and 21b is a photodetection region 23 including a plurality of avalanche photodiodes 12 operating in Geiger mode and a plurality of quenching resistors 13 electrically connected in series with one of the anodes and cathodes of a corresponding one of the plurality of avalanche photodiodes 12. Each of the portions 22a and 22b is provided with an electrode 17 to which a plurality of quenching resistors 13 are connected in parallel, and an electrode 18 to which the other of the anodes and cathodes of the plurality of avalanche photodiodes 12 are connected in parallel. The wiring members 30a and 30b each have a conductor electrically connected to the electrode 17 and a conductor connected to the electrode 18.

[0071] The radiation detector RD1 includes a scintillator 1 that is long in the first direction D1, and semiconductor photodetector elements 10a and 10b that are disposed on side surfaces 1c and 1d of the scintillator 1, respectively. The semiconductor photodetector elements 10a and 10b detect scintillation light that is incident on the side surfaces 1c and 1d on which the semiconductor photodetector elements 10a and 10b are disposed. The length of the scintillator 1 in the second direction D2 is shorter than the length of the scintillator 1 in the first direction D1. Therefore, the distance from the scintillation light generation point GP1 to the side surface 1c and the distance from the scintillation light generation point GP1 to the side surface 1d are short. The time it takes for the scintillation light to reach the semiconductor photodetector elements 10a and 10b is short, and the radiation detector RD1 achieves high time resolution. Because the radiation detector RD1 includes two semiconductor photodetector elements, semiconductor photodetector elements 10a and 10b, it also achieves higher detection sensitivity than a radiation detector that includes a single semiconductor photodetector element disposed on one side surface of the scintillator 1.

[0072] In the radiation detector RD1, the photodetection region 23 of the semiconductor substrate 11a may have a contour shape corresponding to the contour shape of the side surface 1c when viewed from the second direction D2. The photodetection region 23 of the semiconductor substrate 11b has a contour shape corresponding to the contour shape of the side surface 1d when viewed from the second direction D2. In this case, since the photodetection region 23 does not need to be disposed in a portion of the semiconductor substrate 11a that cannot receive scintillation light, increases in dark count and capacitance in the photodetection region of the semiconductor substrate 11a are suppressed. Since the photodetection region 23 does not need to be disposed in a portion of the semiconductor substrate 11b that cannot receive scintillation light, increases in dark count and capacitance in the photodetection region of the semiconductor substrate 11b are suppressed. Detection errors in scintillation light are reduced. Therefore, this configuration reliably improves the time resolution and detection sensitivity of the semiconductor photodetecting elements 10a and 10b.

[0073] The radiation detector RD1 includes a reinforcing member 45 disposed between the portion 22a and the portion 22b. The reinforcing member 45 covers the portion 22a and the portion 22b and connects the portion 22a and the portion 22b together. In this case, the mechanical strength of the portion 22a and the portion 22b is improved by the reinforcing member 45 disposed between the portion 22a and the portion 22b. The wiring members 30a and 30b located in the portion 22a and the portion 22b, respectively, are protected by the reinforcing member 45.

[0074] In radiation detector RD1, semiconductor substrate 11a has surface 11c facing scintillator 1 in second direction D2 and surface 11d facing surface 11c in second direction D2. Semiconductor substrate 11b has surface 11e facing scintillator 1 in second direction D2 and surface 11f facing surface 11e in second direction D2. Surfaces 11d and 11f are polished surfaces. In a configuration in which the surfaces 11d and 11f are polished surfaces, the semiconductor substrates 11a and 11b can be thinned, and the radiation detector RD1 can be made smaller in size in the thickness direction of the semiconductor substrates 11a and 11b.

[0075] The radiation detector RD1 may include a base 40a having surfaces 40c and 40d facing each other in the second direction D2 and arranged such that a semiconductor substrate 11a is located between surface 40d and the scintillator 1, a base 40b having surfaces 40e and 40f facing each other in the second direction D2 and arranged such that a semiconductor substrate 11b is located between surface 40e and the scintillator 1, terminals 41 and 42 arranged on surface 40c, and terminals 41 and 42 arranged on surface 40e. The base 40a may have a portion 51a covered by the semiconductor substrate 11a and a portion 52a aligned with portion 51a in the first direction D1 and exposed from the semiconductor substrate 11a. The base 40b may have a portion 51b covered by the semiconductor substrate 11b and a portion 52b aligned with portion 51b in the first direction D1 and exposed from the semiconductor substrate 11b. Terminal 41 may be located on portion 52a and electrically connected to electrode 17 disposed on portion 22a through wire 43. Terminal 42 may be located on portion 52a and electrically connected to a second electrode disposed on a second portion through wire 44. Terminal 41 may be located on portion 52b and electrically connected to electrode 17 disposed on portion 22b through wire 43. Terminal 42 may be located on portion 52b and electrically connected to electrode 18 disposed on portion 22b through wire 44. In the configuration including the bases 40a and 40b, the mechanical strength of the radiation detector RD1 is improved, and therefore this configuration reliably realizes a radiation detector RD1 with improved mechanical strength.

[0076] The radiation detector RD1 includes a cover 47a arranged so that the semiconductor substrate 11a is located between the cover 47a and the scintillator 1, and a cover 47b arranged so that the semiconductor substrate 11b is located between the cover 47a and the scintillator 1. The cover 47a and the cover 47b each include at least one of an optical reflector 48 and an electrical insulator 49. In this case, for example, the light reflection characteristics of the scintillation light are improved in a configuration in which the coverings 47a and 47b include the light reflector 48. For example, in a configuration in which the coverings 47a and 47b include the electrical insulator 49, the electrical insulation between the adjacent radiation detectors RD1 is improved.

[0077] In the radiation detector RD1, the wiring member 30a is arranged on the same side of the semiconductor substrate 11a as the scintillator 1. The wiring member 30b is arranged on the same side of the semiconductor substrate 11b as the scintillator 1. In this case, for example, there is no need to prepare a new substrate for connecting wiring member 30a to electrodes 17 and 18 by die bonding. For example, there is no need to prepare a new substrate for connecting wiring member 30b to electrodes 17 and 18 by die bonding. Therefore, this configuration more reliably simplifies the configuration of radiation detector RD1.

[0078] In the radiation detector RD1, the wiring members 30a and 30b and the semiconductor substrates 11a and 11b are flexible. The flexibility of the wiring members 30a is greater than that of the semiconductor substrate 11a. The flexibility of the wiring members 30b is greater than that of the semiconductor substrate 11b. In this case, force from the wiring member 30a is less likely to be applied to the semiconductor substrate 11a, and the semiconductor substrate 11a is less likely to be physically damaged. Force from the wiring member 30b is less likely to be applied to the semiconductor substrate 11b, and the semiconductor substrate 11b is less likely to be physically damaged. Therefore, this configuration reliably maintains the mechanical strength of the radiation detector RD1.

[0079] Second Embodiment The configuration of the radiation detector arrays RA1 and RA2 according to the second embodiment will be described with reference to Fig. 12 and Fig. 13. Fig. 12 is a perspective view showing the radiation detector array RA1 according to the second embodiment, and Fig. 13 is a perspective view showing the radiation detector array RA2 according to the second embodiment.

[0080] As shown in Fig. 12, the radiation detector array RA1 is configured, for example, by a one-dimensional arrangement of a plurality of radiation detectors RD1. The plurality of radiation detectors RD1 are lined up, for example, in the third direction D3. In the example shown in Fig. 12, three radiation detectors RD1 are lined up in the third direction D3. Any two adjacent radiation detectors RD1 from the plurality of radiation detectors RD1 are lined up such that the side surfaces 1e, 1f of the scintillator 1 included in one radiation detector RD1 face each other, and the side surfaces 1e, 1f of the scintillator 1 included in the other radiation detector RD1 face each other. Therefore, any two radiation detectors RD1 adjacent to each other in the third direction D3 are lined up such that the side surface 1e of the scintillator 1 included in one radiation detector RD1 faces each other, for example. Any two radiation detectors RD1 adjacent to each other in the third direction D3 are arranged, for example, so that the side surface 1f of the scintillator 1 provided in one radiation detector RD1 and the side surface 1e of the scintillator 1 provided in the other radiation detector RD1 face each other.

[0081] The semiconductor photodetector element 10a of one radiation detector RD1 and the semiconductor photodetector element 10a of the other radiation detector RD1 are, for example, lined up in one dimension. In this embodiment, the semiconductor photodetector element 10a of one radiation detector RD1 and the semiconductor photodetector element 10a of the other radiation detector RD1 are, for example, lined up in the third direction D3. The semiconductor photodetector element 10b of one radiation detector RD1 and the semiconductor photodetector element 10b of the other radiation detector RD1 are, for example, lined up in one dimension. In this embodiment, the semiconductor photodetector element 10b of one radiation detector RD1 and the semiconductor photodetector element 10b of the other radiation detector RD1 are, for example, lined up in the third direction D3.

[0082] The semiconductor photodetecting elements 10a arranged in one dimension may be integrally formed with each other, for example. The semiconductor photodetecting elements 10b arranged in one dimension may be integrally formed with each other, for example. The semiconductor photodetecting elements 10a, 10b are arranged in the third direction D3, for example. The semiconductor photodetecting elements 10a arranged in one dimension may not be integrally formed with each other, for example. The semiconductor photodetecting elements 10b arranged in one dimension may not be integrally formed with each other, for example.

[0083] Each radiation detector RD1 includes, for example, covering bodies 47a, 47b and a light reflector 56. When each radiation detector RD1 includes the light reflector 56, the side surface 1e of the scintillator 1 included in one radiation detector RD1 and the side surface 1f of the scintillator 1 included in the other radiation detector RD1 face each other in the third direction D3, with the light reflector 56 located between the side surfaces 1e and 1f. Between the side surface 1e of the scintillator 1 included in one radiation detector RD1 and the side surface 1f of the scintillator 1 included in the other radiation detector RD1, for example, a light reflector 56 arranged on one side surface 1e and a light reflector 56 arranged on the other side surface 1f are arranged. Between the side surface 1e of the scintillator 1 included in one radiation detector RD1 and the side surface 1f of the scintillator 1 included in the other radiation detector RD1, for example, one light reflector 56 may be arranged. In this case, for example, the light reflector 56 is arranged on one side surface 1e, and the light reflector 56 is not arranged on the other side surface 1f. Each radiation detector RD1 does not have to be provided with at least one of the covering bodies 47a, 47b and the light reflector 56.

[0084] As shown in Fig. 13, the radiation detector array RA2 is configured, for example, by a plurality of radiation detectors RD1 arranged two-dimensionally in a matrix. Of the plurality of radiation detectors RD1, a plurality of radiation detectors RD1 arranged in the row direction constitute, for example, the radiation detector array RA1 shown in Fig. 12. In the radiation detector array RA2, the radiation detector arrays RA1 are arranged in the column direction. In this embodiment, the column direction is the second direction D2, and the row direction is the third direction D3. Of the plurality of radiation detectors RD1, any two radiation detectors RD1 adjacent to each other in the column direction are arranged so that either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in one radiation detector RD1 faces either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 in the column direction. Therefore, any two radiation detectors RD1 adjacent to each other in the column direction are lined up, for example, so that the semiconductor photodetector element 10a included in one radiation detector RD1 and the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the column direction. Any two radiation detectors RD1 adjacent to each other in the column direction are lined up, for example, so that the semiconductor photodetector element 10b included in one radiation detector RD1 and the semiconductor photodetector element 10a included in the other radiation detector RD1 face each other in the column direction.

[0085] When each radiation detector RD1 is provided with the coverings 47a, 47b, in any two radiation detectors RD1 adjacent to each other in the column direction, for example, the semiconductor photodetector element 10a included in one radiation detector RD1 and the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the column direction with the coverings 47a, 47b located between the semiconductor photodetector elements 10a, 10b. In any two radiation detectors RD1 adjacent to each other in the column direction, for example, the semiconductor photodetector element 10b included in one radiation detector RD1 and the semiconductor photodetector element 10a included in the other radiation detector RD1 face each other in the column direction with the coverings 47b, 47a located between the semiconductor photodetector elements 10b, 10a. In the example shown in Fig. 13, three radiation detectors RD1 are lined up in the third direction D3, and three radiation detectors RD1 are also lined up in the second direction D2. The radiation detector array RA2 is made up of, for example, a total of nine radiation detectors RD1. An end face 1a of one radiation detector RD1 is flush with an end face 1a of the other radiation detector RD1 adjacent thereto in the row or column direction, for example.

[0086] As described above, the radiation detector array RA1 according to this embodiment is a radiation detector array RA1 including a plurality of radiation detectors RD1 arranged one-dimensionally, and the plurality of radiation detectors RD1 are the radiation detectors RD1 according to the first embodiment. The scintillator 1 has a pair of side surfaces 1e, 1f that connect the pair of end surfaces 1a, 1b and also connect the side surface 1c and the side surface 1d. Any two adjacent radiation detectors RD1 among the plurality of radiation detectors RD1 are lined up so that the side surfaces 1e, 1f of the scintillator 1 included in one radiation detector RD1 and the side surfaces 1e, 1f of the scintillator 1 included in the other radiation detector RD1 face each other.

[0087] According to the radiation detector array RA1 of this embodiment, a radiation detector array is realized in which radiation detectors RD1 having high time resolution and high detection sensitivity are arranged one-dimensionally.

[0088] In the second aspect, the first semiconductor photodetector elements arranged in a line are integrally formed with one another, and the second semiconductor photodetector elements arranged in a line are integrally formed with one another. In this case, the mechanical strength of the radiation detector array RA1 in which a plurality of radiation detectors RD1 are arranged one-dimensionally is improved.

[0089] The radiation detector array RA2 according to this embodiment is a radiation detector array RA2 comprising a plurality of radiation detectors RD1 arranged two-dimensionally in a matrix, and the plurality of radiation detectors RD1 arranged in the row direction among the plurality of radiation detectors RD1 are the radiation detector array RA1 according to this embodiment. Any two radiation detectors RD1 adjacent to each other in the column direction among the plurality of radiation detectors RD1 are arranged so that either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in one radiation detector RD1 faces either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 in the column direction. In this case, a radiation detector array RA2 is realized in which radiation detectors RD1 having high time resolution and high detection sensitivity are two-dimensionally arranged in a matrix by configuring radiation detector arrays RA1 arranged one-dimensionally in the column direction. In this embodiment, when radiation detector RD1 is equipped with optical reflector 56, scintillation light incident on side surface 1e of scintillator 1 included in one radiation detector RD1 is unlikely to be incident on side surface 1f of scintillator 1 included in the other radiation detector RD1, for example.

[0090] (Third embodiment) The configuration of radiation detector arrays RA1 and RA2 according to the third embodiment will be described with reference to Figures 14 and 15. Figure 14 is a perspective view showing the radiation detector array RA1 according to the third embodiment. Figure 15 is a perspective view showing the radiation detector array RA2 according to the third embodiment.

[0091] As shown in Fig. 14, the radiation detector array RA1 is configured, for example, by a one-dimensional arrangement of a plurality of radiation detectors RD1. The plurality of radiation detectors RD1 are lined up, for example, in the third direction D3. In the example shown in Fig. 14, three radiation detectors RD1 of the first embodiment are lined up in the third direction D3. Any two adjacent radiation detectors RD1 of the plurality of radiation detectors RD1 are lined up such that the side surfaces 1e and 1f of the scintillator 1 included in one radiation detector RD1 face each other, and either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the third direction D3. Therefore, any two radiation detectors RD1 adjacent to each other in the third direction D3 are lined up such that the side surface 1e of the scintillator 1 included in one radiation detector RD1 faces each other in the third direction D3. Any two radiation detectors RD1 adjacent to each other in the third direction D3 are arranged, for example, so that the side surface 1f of the scintillator 1 provided in one radiation detector RD1 and the semiconductor photodetector element 10a provided in the other radiation detector RD1 face each other in the third direction D3.

[0092] Each radiation detector RD1 includes, for example, coatings 47a, 47b and a light reflector 56. In this case, for example, in any two radiation detectors RD1 adjacent to each other in the third direction D3, the side surface 1e of the scintillator 1 included in one radiation detector RD1 and the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the third direction D3, with the coating 47b and the light reflector 56 located between the side surface 1e and the semiconductor photodetector element 10b. For example, in any two radiation detectors RD1 adjacent to each other in the third direction D3, the side surface 1f of the scintillator 1 included in one radiation detector RD1 and the semiconductor photodetector element 10a included in the other radiation detector RD1 face each other in the third direction D3, with the coating 47a and the light reflector 56 located between the side surface 1f and the semiconductor photodetector element 10a. Each radiation detector RD1 may not have at least one of the covering bodies 47a, 47b and the light reflector .

[0093] As shown in Fig. 15, the radiation detector array RA2 is configured, for example, by two-dimensionally arranging a plurality of radiation detectors RD1 according to the first embodiment in a matrix. Of the plurality of radiation detectors RD1, the plurality of radiation detectors RD1 arranged in the row direction are, for example, the radiation detector array RA1 shown in Fig. 14. Therefore, in the radiation detector array RA2, the radiation detector arrays RA1 are arranged in the column direction. In this embodiment, the column direction is the second direction D2, and the row direction is the third direction D3. Of the plurality of radiation detectors RD1, any two radiation detectors RD1 adjacent to each other in the column direction are arranged such that the side surfaces 1e, 1f of the scintillator 1 included in one radiation detector RD1 and either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the column direction. For example, the opposing direction of the side surfaces 1e, 1f of the scintillator 1 included in one radiation detector RD1 and the opposing direction of the side surfaces 1e, 1f of the scintillator 1 included in the other radiation detector RD1 intersect with each other. Therefore, any two radiation detectors RD1 adjacent to each other in the column direction are lined up, for example, so that the side surface 1e of the scintillator 1 in one radiation detector RD1 and the semiconductor photodetector element 10a in the other radiation detector RD1 face each other in the column direction. Any two radiation detectors RD1 adjacent to each other in the column direction are lined up, for example, so that the side surface 1f of the scintillator 1 in one radiation detector RD1 and the semiconductor photodetector element 10b in the other radiation detector RD1 face each other in the column direction.

[0094] 15, three radiation detectors RD1 are lined up in the third direction D3, and three radiation detectors RD1 are lined up in the second direction D2. The radiation detector array RA2 is composed of, for example, a total of nine radiation detectors RD1. The end face 1a of one radiation detector RD1 is flush with the end face 1a of another radiation detector RD1 adjacent to it in the row or column direction, for example.

[0095] When each radiation detector RD1 includes the coatings 47a, 47b and the light reflector 56, for example, the side surface 1e of the scintillator 1 included in one radiation detector RD1 and the semiconductor photodetector element 10a included in the other radiation detector RD1 face each other in the column direction, with the coating 47a and the light reflector 56 located between the side surface 1e and the semiconductor photodetector element 10a. For example, the side surface 1f of the scintillator 1 included in one radiation detector RD1 and the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the column direction, with the coating 47b and the light reflector 56 located between the side surface 1f and the semiconductor photodetector element 10b.

[0096] As described above, the radiation detector array RA1 according to the third aspect is a radiation detector array RA1 including a plurality of radiation detectors RD1 arranged one-dimensionally, and the plurality of radiation detectors RD1 may be the radiation detectors RD1 described above. The scintillator 1 has a pair of side surfaces 1e, 1f connecting the pair of end surfaces 1a, 1b and connecting the side surface 1c and the side surface 1d. Any two adjacent radiation detectors RD1 among the plurality of radiation detectors RD1 are arranged side by side such that the side surfaces 1e, 1f of the scintillator 1 included in one radiation detector RD1 face each other, and either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other.

[0097] According to the radiation detector array RA1 of this embodiment, a radiation detector array is realized in which radiation detectors RD1 having high time resolution and high detection sensitivity are arranged one-dimensionally.

[0098] The radiation detector array RA2 includes a plurality of radiation detectors RD1 arranged two-dimensionally in a matrix, and the plurality of radiation detectors RD1 arranged in the row direction among the plurality of radiation detectors RD1 are the radiation detector array RA1 according to this embodiment, and any two radiation detectors RD1 adjacent to each other in the column direction among the plurality of radiation detectors RD1 are arranged so that the side surfaces 1e, 1f of the scintillator 1 included in one radiation detector RD1 and either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the column direction. In this case, in a configuration in which a plurality of radiation detectors RD1 are two-dimensionally arranged in a matrix, a radiation detector array RA2 is realized in which radiation detectors RD1 having high time resolution and high detection sensitivity are two-dimensionally arranged in a matrix. Since the side surfaces 1e, 1f and either the semiconductor photodetector element 10a or the semiconductor photodetector element 10b included in the other radiation detector RD1 face each other in the column direction, the plurality of radiation detectors RD1 can be two-dimensionally arranged in a smaller space than in a configuration in which the semiconductor photodetector elements 10a, 10b face each other. In this embodiment, for example, compared to a configuration in which the side surface 1e of the scintillator 1 included in one radiation detector RD1 and the side surface 1f of the scintillator 1 included in the other radiation detector RD1 face each other, scintillation light incident on the side surface 1e of the scintillator 1 included in one radiation detector RD1 is less likely to be incident on the scintillator 1 included in the other radiation detector RD1. Compared to a configuration in which the side surface 1f of the scintillator 1 included in one radiation detector RD1 and the side surface 1e of the scintillator 1 included in the other radiation detector RD1 face each other, scintillation light incident on the side surface 1f of the scintillator 1 included in one radiation detector RD1 is less likely to be incident on the scintillator 1 included in the other radiation detector RD1.

[0099] An example of a method for manufacturing the radiation detector RD1 will be described with reference to Fig. 16. The order of the steps in the manufacturing method may be reversed. In the example of the manufacturing method, first, the scintillator 1 and the semiconductor photodetector elements 10a and 10b are prepared (S101).

[0100] Next, wiring members 30a and 30b are prepared and connected to the semiconductor light-detecting elements 10a and 10b (S102). For example, the wiring member 30a is connected to the semiconductor light-detecting element 10a, and the wiring member 30b is connected to the semiconductor light-detecting element 10b. The wiring members 30a and 30b have a conductor 31 and a conductor 32, and the conductor 31 is electrically connected to the electrode 17 of the semiconductor light-detecting elements 10a and 10b. The conductor 32 is electrically connected to the electrode 18 of the semiconductor light-detecting elements 10a and 10b. The conductor 31 is electrically connected to the electrode 17 via a conductive bump 33, for example. The conductor 32 is connected to the electrode 18 via a conductive bump 33, for example.

[0101] Next, the scintillator 1 and the semiconductor photodetector elements 10a and 10b are integrated together (S103). This integration is performed, for example, with an adhesive. The semiconductor photodetector element 10a is disposed, for example, on the side surface 1c of the scintillator 1, and the semiconductor photodetector element 10b is disposed, for example, on the side surface 1d of the scintillator 1. Next, a reinforcing member 45 is disposed between the portion 22a and the portion 22b.

[0102] Next, after the reinforcing member 45 is placed, the surfaces 11d and 11f are polished, for example, to thin the semiconductor photodetector elements 10a and 10b (S104). The thinning of the elements is performed, for example, by mechanical polishing or chemical polishing. The thinning of the elements is performed, for example, on the radiation detector array RA1 configured by a one-dimensional array of multiple radiation detectors RD1. That is, the semiconductor photodetector elements 10a and 10b of the radiation detector array RA1 are thinned. The thinned multiple radiation detector arrays RA1 are, for example, singulated to produce individual radiation detectors RD1. The singulation is performed, for example, by dicing. The thinned multiple radiation detector arrays RA1 may be arranged, for example, in a column direction without being singulated. A radiation detector array RA2 may be produced in which a multiple radiation detector array RA1 is two-dimensionally arranged in a matrix.

[0103] This embodiment includes a method for manufacturing a radiation detector. The method for manufacturing a radiation detector is as follows. (Method 1) Providing a scintillator; providing a semiconductor photodetector element; Integrating the scintillator and the semiconductor photodetector element; and thinning the semiconductor photodetector element integrated with the scintillator; The scintillator to be prepared has a pair of end faces facing each other in a first direction and side faces connecting the pair of end faces, and has a length in the first direction that is greater than a length in a second direction perpendicular to the side faces, and the length of the side faces in the first direction is greater than a width of the side faces in a third direction perpendicular to the first direction and the second direction, The prepared semiconductor photodetector element includes a semiconductor substrate having a first main surface and a second main surface facing each other, the semiconductor substrate having a first portion in which a photodetection region is disposed, the photodetection region including a plurality of avalanche photodiodes operating in Geiger mode and a plurality of quenching resistors electrically connected in series with one of the anode and the cathode of a corresponding one of the plurality of avalanche photodiodes, and a second portion aligned with the first portion in a direction perpendicular to a direction in which the first main surface and the second main surface face each other, Integrating the scintillator and the semiconductor photodetector element includes integrating the scintillator and the semiconductor photodetector element such that the side surface and the first main surface face each other, the first portion is covered by the side surface, and the second portion is exposed from the scintillator, and applying a resin so as to be in contact with the scintillator and the second portion, The method for manufacturing a radiation detector, wherein thinning the semiconductor photodetector element includes thinning the semiconductor substrate from the second main surface side. (Method 2) Providing a wiring member; and further comprising electrically connecting the wiring member to the semiconductor light-detecting element; the semiconductor photodetector element further includes a first electrode and a second electrode disposed in the second portion, the first electrode being connected in parallel to the plurality of quenching resistors, and the second electrode being connected in parallel to the other of the anodes and cathodes of the plurality of avalanche photodiodes; The wiring member provided has a first conductor and a second conductor, electrically connecting the wiring member includes connecting the first conductor to the first electrode and connecting the second conductor to the second electrode; The method for manufacturing a radiation detector according to Manufacturing Method 1, wherein applying the resin includes applying the resin so as to contact a portion of the wiring member electrically connected to the semiconductor light detection element that is located on the second portion. (Method 3) The scintillator further has another side surface opposite to the side surface, The provided semiconductor photodetector elements include a first semiconductor photodetector element and a second semiconductor photodetector element, each having the semiconductor substrate having the first portion and the second portion; The integration of the scintillator and the semiconductor photodetector element includes: integrating the scintillator and the first semiconductor photodetector element such that the side surface and the first main surface face each other, the first portion is covered by the side surface, and the second portion is exposed from the scintillator; integrating the scintillator and the second semiconductor photodetector element such that the other side surface and the first main surface face each other, the first portion is covered by the other side surface, and the second portion is exposed from the scintillator; and applying a resin to contact the scintillator and the second portion of the semiconductor substrate of each of the first semiconductor photodetector element and the second semiconductor photodetector element; The method for manufacturing a radiation detector according to Manufacturing Method 1, wherein thinning the semiconductor photodetector elements includes thinning the semiconductor substrates of the first semiconductor photodetector element and the second semiconductor photodetector element from the second main surface side. (Method 4) Providing a wiring member; and further comprising electrically connecting the wiring member to the semiconductor light-detecting element; each of the first semiconductor photodetector element and the second semiconductor photodetector element further includes a first electrode and a second electrode disposed in the second portion, the first electrode being connected in parallel to the plurality of quenching resistors, and the second electrode being connected in parallel to the other of the anodes and cathodes of the plurality of avalanche photodiodes; the wiring members provided include a first wiring member and a second wiring member each having a first conductor and a second conductor, electrically connecting the wiring members includes connecting the first conductor of the first wiring member to the first electrode of the first semiconductor light-detecting element, connecting the second conductor of the first wiring member to the second electrode of the first semiconductor light-detecting element, connecting the first conductor of the second wiring member to the first electrode of the second semiconductor light-detecting element, and connecting the second conductor of the second wiring member to the second electrode of the second semiconductor light-detecting element, the applying of the resin includes applying the resin so as to be in contact with a portion of the first wiring member electrically connected to the first semiconductor photodetector element that is located on the second portion, and a portion of the second wiring member electrically connected to the second semiconductor photodetector element that is located on the second portion.

[0104] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0105] In radiation detectors RD1, RD1, the photodetection region 23 does not have to have a contour shape corresponding to the contour shape of the side surfaces 1c, 1d when viewed from the second direction D2. In a configuration in which the photodetection region 23 has a contour shape corresponding to the contour shape of the side surfaces 1c, 1d, as described above, the photodetection region 23 does not have to be disposed in a location on the semiconductor substrates 11a, 11b that cannot receive scintillation light, thereby suppressing increases in dark count and capacitance in the photodetection region 23. Therefore, this configuration reliably improves the time resolution of radiation detector RD1. The radiation detector RD1 does not necessarily have to include the bases 40a and 40b. In a configuration in which the radiation detector RD1 includes the bases 40a and 40b, the mechanical strength of the semiconductor substrates 11a and 11b is reinforced, as described above. Therefore, the radiation detector RD1 reliably realizes the semiconductor photodetector elements 10a and 10b with reinforced mechanical strength. The radiation detector RD1 does not necessarily have to include the reinforcing body 45. In a configuration in which the radiation detector RD1 includes the reinforcing body 45, as described above, the mechanical strength of the portion 22a and the portion 22b is improved by the reinforcing body 45 disposed between the portion 22a and the portion 22b. The radiation detector RD1 does not necessarily have to include the coatings 47a and 47b. In a configuration in which the radiation detector RD1 includes the coatings 47a and 47b, for example, the coatings 47a and 47b may include a light reflector 48, thereby improving the light reflection characteristics of the scintillation light. For example, the coatings 47a and 47b may include an electrical insulator 49, thereby improving the electrical insulation of the radiation detector RD1. The wiring members 30a, 30b do not have to be arranged on the same side of the semiconductor substrates 11a, 11b as the scintillator 1. In a configuration in which the wiring members 30a, 30b are arranged on the same side of the semiconductor substrates 11a, 11b as the scintillator 1, for example, there is no need to prepare a new substrate for connecting the wiring members 30a, 30b to the electrodes 17, 18, respectively, by die bonding. Therefore, this configuration more reliably simplifies the configuration of the radiation detector RD1. The flexibility of the wiring members 30a, 30b does not need to be greater than the flexibility of the semiconductor substrates 11a, 11b. If the flexibility of the wiring members 30a, 30b is greater than the flexibility of the semiconductor substrates 11a, 11b, as described above, vibrations are less likely to be transmitted from the wiring members 30a, 30b to the semiconductor substrates 11a, 11b. Therefore, this configuration reliably maintains the mechanical strength of the radiation detector RD1. In the embodiment, an example has been described in which a semiconductor photodetector element is arranged on each of two side surfaces 1c and 1d of the scintillator 1, but a semiconductor photodetector element may also be arranged on each of four side surfaces 1c, 1d, 1e, and 1f of the scintillator 1. [Explanation of symbols]

[0106] 1...scintillator, 1a...end face, 1b...end face, 1c...side face, 1d...side face, 1e...side face, 1f...side face, 10a...semiconductor photodetector element, 10b...semiconductor photodetector element, 11a...semiconductor substrate, 11b...semiconductor substrate, 12...avalanche photodiode, 13...quenching resistor, 14a...conductor wire, 14b...conductor wire, 17...electrode, 18...electrode, 21a...portion, 21b...portion, 22a...portion, 22b... Part, 23...light detection area, 30a...wiring member, 30b...wiring member, 41...terminal, 42...terminal, 45...reinforcing body, 47a...coating body, 47b...coating body, 48...light reflector, 49...electrical insulator, 51a...part, 51b...part, 52a...part, 52b...part, D1...first direction, D2...second direction, D3...third direction, RA1...radiation detector array, RA2...radiation detector array, RD1...radiation detector.

Claims

1. a scintillator having a rectangular shape when viewed from a first direction, and having a pair of end faces opposing each other in the first direction, and a first side surface and a second side surface opposing each other in a second direction intersecting the first direction and connecting the pair of end faces; a first semiconductor photodetector element having a first semiconductor substrate disposed so as to face the first side surface; a second semiconductor photodetector element having a second semiconductor substrate disposed so as to face the second side surface; a first wiring member electrically connected to the first semiconductor photodetector element; a second wiring member electrically connected to the second semiconductor light-detecting element; Equipped with a length of the scintillator in the first direction is greater than a length of the scintillator in the second direction and a length of the scintillator in a third direction parallel to the first side surface; a length of the first side surface in the first direction greater than a width of the first side surface in the third direction; a length of the second side in the first direction greater than a width of the second side in the third direction; the first semiconductor substrate has a first portion covered by the first side surface and a second portion aligned with the first portion in the first direction and exposed from the first side surface; the second semiconductor substrate has a third portion covered by the second side surface and a fourth portion aligned with the third portion in the first direction and exposed from the second side surface, a photodetection region including a plurality of avalanche photodiodes operating in a Geiger mode and a plurality of quenching resistors electrically connected in series with one of an anode and a cathode of a corresponding one of the plurality of avalanche photodiodes; a first electrode to which the plurality of quenching resistors are connected in parallel and a second electrode to which the other of the anodes and the cathodes of the plurality of avalanche photodiodes is connected in parallel are disposed in each of the second portion and the fourth portion; The first wiring member and the second wiring member each have a conductor electrically connected to the first electrode and a conductor connected to the second electrode.

2. When viewed from the second direction, the light detection region of the first semiconductor substrate has a contour shape corresponding to a contour shape of the first side surface, The radiation detector according to claim 1 , wherein when viewed from the second direction, the light detection region of the second semiconductor substrate has a contour shape that corresponds to a contour shape of the second side surface.

3. further comprising a reinforcement member disposed between the second portion and the fourth portion; The radiation detector according to claim 1 , wherein the reinforcing member covers the second portion and the fourth portion and connects the second portion and the fourth portion together.

4. the first semiconductor substrate has a first surface facing the scintillator in the second direction and a second surface facing the first surface in the second direction; the second semiconductor substrate has a third surface facing the scintillator in the second direction and a fourth surface facing the third surface in the second direction; 4. The radiation detector according to claim 1, wherein the second surface and the fourth surface are polished surfaces.

5. a first base having a fifth surface and a sixth surface facing each other in the second direction and arranged such that the first semiconductor substrate is located between the fifth surface and the scintillator; a second substrate having a seventh surface and an eighth surface facing each other in the second direction and arranged such that the second semiconductor substrate is located between the seventh surface and the scintillator; a first terminal and a second terminal disposed on the fifth surface; a third terminal and a fourth terminal disposed on the seventh surface; Further provided with the first base body has a fifth portion covered with the first semiconductor substrate and a sixth portion aligned with the fifth portion in the first direction and exposed from the first semiconductor substrate, the second base has a seventh portion covered with the second semiconductor substrate and an eighth portion aligned with the seventh portion in the first direction and exposed from the second semiconductor substrate, the first terminal is located on the sixth portion and is electrically connected to the first electrode disposed on the second portion through a first wire; the second terminal is located on the sixth portion and is electrically connected to the second electrode disposed on the second portion through a second wire; the third terminal is located on the eighth portion and is electrically connected to the first electrode disposed on the fourth portion through a third wire; 5. The radiation detector according to claim 1, wherein the fourth terminal is located on the eighth portion and is electrically connected to the second electrode disposed on the fourth portion through a fourth wire.

6. a first covering body arranged so that the first semiconductor substrate is located between the first covering body and the scintillator; a second covering body arranged so that the second semiconductor substrate is located between the second covering body and the scintillator; The radiation detector according to any one of claims 1 to 5, wherein the first coating and the second coating include at least one of an optical reflector and an electrical insulator.

7. the first wiring member is disposed on the same side as the scintillator with respect to the first semiconductor substrate, 7. The radiation detector according to claim 1, wherein the second wiring member is disposed on the same side as the scintillator with respect to the second semiconductor substrate.

8. the first wiring member, the second wiring member, the first semiconductor substrate, and the second semiconductor substrate are flexible; the flexibility of the first wiring member is greater than the flexibility of the first semiconductor substrate; 8. The radiation detector according to claim 1, wherein the second wiring member has a flexibility greater than that of the second semiconductor substrate.

9. A radiation detector array comprising a plurality of radiation detectors arranged in one dimension, The plurality of radiation detectors are the radiation detectors according to any one of claims 1 to 8, the scintillator further has a pair of third side surfaces connecting the pair of end surfaces and connecting the first side surface and the second side surface, any two adjacent radiation detectors among the plurality of radiation detectors are arranged side by side such that the third side surface of the scintillator included in one of the radiation detectors faces the third side surface of the scintillator included in the other of the radiation detectors.

10. The first semiconductor photodetector elements arranged in one dimension are integrally formed with one another, The radiation detector array according to claim 9 , wherein each of the second semiconductor photodetector elements arranged in one dimension is formed integrally with one another.

11. A radiation detector array including a plurality of radiation detectors arranged two-dimensionally in a matrix, The plurality of radiation detectors arranged in a row direction among the plurality of radiation detectors are the radiation detector array according to claim 9 or 10, any two radiation detectors adjacent to each other in the column direction among the plurality of radiation detectors are arranged such that either the first semiconductor photodetection element or the second semiconductor photodetection element included in one of the radiation detectors faces either the first semiconductor photodetection element or the second semiconductor photodetection element included in the other of the radiation detectors.

12. A radiation detector array comprising a plurality of radiation detectors arranged in one dimension, The plurality of radiation detectors are the radiation detectors according to any one of claims 1 to 8, the scintillator further has a pair of third side surfaces connecting the pair of end surfaces and connecting the first side surface and the second side surface, any two adjacent radiation detectors among the plurality of radiation detectors are arranged side by side such that the third side surface of the scintillator included in one of the radiation detectors faces either the first semiconductor photodetector element or the second semiconductor photodetector element included in the other radiation detector.

13. A radiation detector array including a plurality of radiation detectors arranged two-dimensionally in a matrix, The plurality of radiation detectors arranged in a row direction among the plurality of radiation detectors is the radiation detector array according to claim 12, any two radiation detectors adjacent to each other in the column direction among the plurality of radiation detectors are arranged side by side such that the third side surface of the scintillator included in one of the radiation detectors and either the first semiconductor photodetector element or the second semiconductor photodetector element included in the other of the radiation detectors face each other in the column direction.

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