Detection device and radiation specification device

Abstract

To solve a problem in which the other radiations may arrive at a radiation detector and the usefulness of data regarding the other radiations is lower than the usefulness of data of Compton scattering.SOLUTION: A detection device for detecting radiations comprises: a container for housing gas; an electronic detector that is positioned inside the container and generates an analog signal by detecting electrons generated by Compton scattering; a drift electrode that opposes the electronic detector; a radiation detector for generating an analog signal by detecting radiations scattered by Compton scattering; a first read circuit for digitizing the analog signal generated by the radiation detector, generating first data, and storing the first data in a first buffer; and a second read circuit for digitizing the analog signal generated by the electronic detector and generating second data. The first read circuit transmits first final data including the first data stored in the first buffer to an external computer according to a first trigger signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] TECHNICAL FIELD An embodiment of the present disclosure relates to a detection device and a radiation identification device for detecting radiation. [Background technology]

[0002] Known radiation detection devices that detect Compton-scattered radiation and electrons generated by Compton scattering are disclosed in, for example, Patent Documents 1 to 3. The detection device includes a container that contains a gas, an electron detector that detects electrons generated by Compton scattering, and a radiation detector that detects radiation scattered by Compton scattering.

[0003] Data on electrons detected by electron detectors is useful for analyzing radiation. For example, as described in Patent Document 1, information on the scattering direction of radiation is calculated from information on the position of radiation detected by the radiation detector and information on the point of origin of electrons. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-148448 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-161522 [Patent Document 3] International Publication No. 2017 / 209059 Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to the radiation scattered by Compton scattering, other radiation may reach the radiation detector. The other radiation may be radiation that reaches the radiation detector without being scattered inside the container, or radiation that reaches the radiation detector without passing through the container. The other radiation does not involve the generation of electrons inside the container. For this reason, analysis of the other radiation is limited compared to analysis of radiation scattered by Compton scattering. Therefore, the usefulness of data on the other radiation is lower than that of data on radiation scattered by Compton scattering.

[0006] The radiation data acquired by the radiation detector is transmitted to a computer. If all the data relating to the radiation acquired by the radiation detector is transmitted to the computer, the load on the computer becomes heavy.

[0007] An embodiment of the present disclosure aims to provide a detection device that can effectively solve such problems. [Means for solving the problem]

[0008] The embodiments of the present disclosure relate to the following [1] to

[28] . [1] A detection device for detecting radiation, a container containing a gas; an electron detector located inside the vessel for detecting electrons generated by Compton scattering and generating an analog signal; a drift electrode facing the electron detector; a radiation detector that detects the radiation scattered by the Compton scattering and generates an analog signal; a first readout circuit that digitizes the analog signal generated by the radiation detector to generate first data and stores the first data in a first buffer; a second readout circuit that digitizes the analog signal generated by the electron detector to generate second data; The first readout circuit transmits first final data including the first data stored in the first buffer to an external computer in response to a first trigger signal.

[0009] [2] In the detection device described in [1], the first final data may include information about the time when the first data was stored in the first buffer.

[0010] [3] In the detection device described in [1] or [2], the radiation detector may include a plurality of detection elements, and the first final data may include information regarding the arrival position of the radiation on the radiation detector.

[0011] [4] In the detection device described in [3], the first final data may include information regarding the intensity of the analog signal generated by the radiation detector.

[0012] [5] In the detection device described in any one of [1] to [4], the first buffer of the first readout circuit may store the first data for a first storage period, and the first storage period may be equal to or shorter than a maximum transit time. The maximum transit time may be the time required for electrons to travel from the drift electrode to the electron detector.

[0013] [6] In the detection device described in [5], the maximum transit time may be 10.24 μs or less.

[0014] [7] In the detection device according to any one of [1] to [6], the first trigger signal may be generated in response to generation of the second data.

[0015] [8] In the detection device described in [7], the detection device may include a logic circuit connected to the first readout circuit and the second readout circuit, the second readout circuit may generate a second hit signal when the intensity of the analog signal of the electronic detector exceeds a threshold, and the logic circuit may generate the first trigger signal in response to generation of the second hit signal.

[0016] [9] In the detection device described in [8], the second readout circuit may include a second buffer in which the second data is stored, the logic circuit may generate a second trigger signal in response to generation of the second hit signal, and the second readout circuit may transmit second final data including the second data stored in the second buffer to the computer in response to the second trigger signal.

[0017]

[10] In the detection device described in [9], the logic circuit may generate the first trigger signal and the second trigger signal simultaneously.

[0018]

[11] In the detection device described in [9] or

[10] , the logic circuit may generate the second trigger signal after a second delay time has elapsed since the second hit signal was generated in the electron detector.

[0019]

[12] In the detection device described in

[11] , the second delay time may be equal to or less than a maximum transit time, which may be the time required for an electron to travel from the drift electrode to the electron detector.

[0020]

[13] In the detection device described in

[11] or

[12] , the second buffer of the second readout circuit may store the second data for a second storage period, and the second storage period may be equal to or longer than a second delay time.

[0021]

[14] In the detection device described in any one of [9] to

[13] , the electron detector may include a plurality of anode electrodes and a plurality of cathode electrodes, the analog signals of the electron detector may include anode analog signals generated by the plurality of anode electrodes and cathode analog signals generated by the plurality of cathode electrodes, the second readout circuit may generate an anode hit signal when the intensity of the anode analog signal exceeds a threshold, and may generate a cathode hit signal when the intensity of the cathode analog signal exceeds a threshold, and the logic circuit may generate the second trigger signal in response to the generation of both the anode hit signal and the cathode hit signal.

[0022]

[15] In the detection device according to any one of [9] to

[14] , the second final data may include information relating to the intensity of the analog signal generated by the electron detector.

[0023]

[16] In the detection device described in

[15] , the second readout circuit may acquire information about the intensity of the analog signal generated by the electron detector at a sampling frequency of 50 MHz or less.

[0024]

[17] In the detection device described in

[15] , the second readout circuit may acquire information about the intensity of the analog signal generated by the electron detector at a sampling frequency of 10 MHz or more and 20 MHz or less.

[0025]

[18] In the detection device described in any one of [8] to

[17] , the first readout circuit may generate a first hit signal when the intensity of the analog signal of the radiation detector exceeds a threshold, and the logic circuit may generate the first trigger signal when the second hit signal is generated within a first sustain period after the first hit signal is generated.

[0026]

[19] In the detection device according to

[18] , the first sustain period may be equal to or shorter than a maximum transit time, which may be the time required for electrons to travel from the drift electrode to the electron detector.

[0027]

[20] In the detection device described in any one of [8] to

[17] , the first readout circuit may generate a first hit signal when the intensity of the analog signal of the radiation detector exceeds a threshold, and the logic circuit may generate the first trigger signal and the second trigger signal when the second hit signal is generated within a first sustain period after the first hit signal is generated.

[0028]

[21] In the detection device described in any one of [1] to [6], the first readout circuit may generate a first hit signal when the intensity of the analog signal of the radiation detector exceeds a threshold, and the first trigger signal may be generated after a first delay time has elapsed since the first hit signal was generated.

[0029]

[22] In the detection device according to

[21] , the first delay time may be 0.45 to 1.00 times the maximum transit time, which may be the time required for an electron to travel from the drift electrode to the electron detector.

[0030]

[23] In the detection device described in

[21] or

[22] , the second readout circuit may generate a second hit signal when the intensity of the analog signal of the electronic detector exceeds a threshold, and the first trigger signal may be generated when the second hit signal is generated during the first delay time.

[0031]

[24] In the detection device according to any one of [1] to

[23] , the first readout circuit may transmit information relating to a detection delay time in the radiation detector to the computer.

[0032]

[25] In the detection device described in

[24] , the detection delay time may be calculated based on the intensity of the analog signal generated by the electronic detector.

[0033]

[26] A radiation identification device, A detection device according to any one of [1] to

[25] , a computer that receives the first final data and the second final data transmitted by the detection device, The computer calculates the incident direction of the radiation to the detection device based on the first final data and the second final data.

[0034]

[27] A radiation identification device, A detection device according to any one of [1] to

[25] , a computer that receives the first final data and the second final data transmitted by the detection device, The computer images the position of a radiation source emitting radiation based on the first final data and the second final data.

[0035]

[28] A radiation identification device,

[24] or

[25] , and a detection device according to a computer that receives the first final data, the second final data, and information about the detection delay time transmitted by the detection device, The computer identifies coordinates of electrons generated by Compton scattering based on the first final data, the second final data, and information related to the detection delay time.

[0036] According to embodiments of the present disclosure, the amount of radiation-related data sent to a computer can be reduced. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a cross-sectional view showing an example of a detection device. [Figure 2] FIG. 1 is a perspective view showing an example of an electron detector. [Figure 3] FIG. 1 is a cross-sectional view showing an example of an electron detector. [Figure 4] FIG. 1 is a perspective view illustrating an example of a radiation detector. [Figure 5] FIG. 1 is a diagram showing an example of Compton scattering occurring in a detection device. [Figure 6] FIG. 2 is a diagram showing how electrons reach an electron detector. [Figure 7] FIG. 2 is a diagram showing an example of an analog signal generated by a radiation detector and an analog signal generated by an electron detector. [Figure 8] FIG. 10 is a diagram illustrating an example of a circuit for generating data. [Figure 9] FIG. 2 is a diagram illustrating an example of a second readout circuit and a logic circuit. [Figure 10] FIG. 2 is a diagram illustrating an example of an anode readout circuit. [Figure 11] FIG. 2 is a diagram illustrating an example of a first readout circuit. [Figure 12] FIG. 10 is a diagram illustrating an example of signal processing. [Figure 13] 10A and 10B are diagrams illustrating an example of first final data and second final data transmitted to a computer. [Figure 14] FIG. 10 is a diagram illustrating an example of signal processing. [Figure 15] FIG. 10 is a diagram illustrating an example of signal processing in a first modified example. [Figure 16] FIG. 10 is a diagram showing a second readout circuit and a logic circuit in a second modified example. [Figure 17] FIG. 10 is a diagram illustrating signal processing in a second modified example. [Figure 18] FIG. 10 is a perspective view showing an electron detector in a third modified example. [Figure 19] FIG. 10 is a diagram illustrating an example of a second readout circuit and a logic circuit in a third modified example. [Figure 20] FIG. 10 is a diagram illustrating a first readout circuit, a second readout circuit, and a logic circuit in a fourth modified example. [Figure 21]FIG. 10 is a diagram illustrating signal processing in a fourth modified example. [Figure 22] FIG. 1 is a diagram showing the configuration of an apparatus for measuring maximum travel time. [Figure 23] 23 is a graph showing the number of electrons detected by the device of FIG. 22. [Figure 24] FIG. 10 is a diagram showing an analog signal in a fifth modified example. [Figure 25] FIG. 13 is a diagram illustrating signal processing in a sixth modified example. [Figure 26] FIG. 13 is a diagram illustrating signal processing in a sixth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0038] The embodiments described below are examples of embodiments of the present disclosure, and the present disclosure should not be construed as being limited to these embodiments. Furthermore, in this specification, terms such as "substrate," "base material," "sheet," and "film" are not distinguished from one another solely based on differences in name. For example, "substrate" and "base material" are concepts that also include members that may be called sheets or films. Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel" and "orthogonal," and values ​​of lengths and angles, are not limited to their strict meanings but are interpreted to include a range within which similar functions can be expected.

[0039] In the drawings referred to in this specification, the same parts or parts having similar functions are denoted by the same or similar reference numerals, and repeated explanations thereof may be omitted. Furthermore, for the convenience of explanation, the dimensional ratios of the drawings may differ from the actual ratios, and some components may be omitted from the drawings.

[0040] In this specification, when multiple upper limit candidates and multiple lower limit candidate values ​​are listed for a certain parameter, the numerical range of the parameter may be constructed by combining any one upper limit candidate with any one lower limit candidate. For example, consider a description that reads, "Parameter B is, for example, A1 or more, or may be A2 or more, or may be A3 or more. Parameter B is, for example, A4 or less, or may be A5 or less, or may be A6 or less." In this case, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[0041] Hereinafter, the configuration of a detection device 10 according to an embodiment of the present disclosure will be described in detail with reference to the drawings. First, an overview of the detection device 10 will be described. FIG. 1 is a cross-sectional view showing an example of the detection device 10.

[0042] (Detection device) The detection device 10 includes a container 20, an electron detector 30 and a drift electrode 40 located inside the container 20, and a radiation detector 50. The container 20 is, for example, a chamber. At least a rare gas such as argon or xenon is contained inside the container 20. In addition to the rare gas, a quenching gas having a quenching effect such as carbon dioxide or methane may also be contained inside the container 20.

[0043] The container 20 includes a first portion 21, a second portion 22 facing the first portion 21 in a first direction D1, and a side portion 23 extending from the first portion 21 toward the second portion 22. The detection device 10 can be used to detect radiation entering the container 20 through the first portion 21. As shown in FIG. 1 , the container 20 may have a cylindrical shape. That is, the side portion 23 may have a circular cross section. Although not shown, the container 20 may have a shape other than a cylindrical shape, such as a cube or rectangular parallelepiped. The first portion 21 may be curved so as to be convex toward the outside of the container 20. The container 20 may include a corner 24 located between the first portion 21 and the side portion 23. The first portion 21 may extend flat. The corner 24 may include a surface extending in a direction different from the first portion 21 and the side portion 23.

[0044] The radiation-emitting object is located outside the container 20. The first portion 21 may include the surface of the container 20 that is closest to the object.

[0045] It is preferable that the material of the container 20 is one that allows radiation to easily pass through. This can prevent the radiation from being absorbed or scattered by the container 20 while passing through the container 20. The container 20 may contain, for example, plastic or metal. The plastic may be fiber-reinforced plastic. When a metal is used, the container 20 may be made of a single metal element or an alloy. For example, aluminum or an aluminum alloy may be used as the metal. To reduce the weight of the container 20, a metal with a specific gravity of less than 4 may be used.

[0046] When the container 20 includes plastic, the thickness of the container 20 is, for example, 1 mm or more, optionally 5 mm or more, or 10 mm or more. The thickness of the container 20 is, for example, 30 mm or less, optionally 25 mm or less, or optionally 20 mm or less.

[0047] When the container 20 contains a metal, the thickness of the container 20 is, for example, 2 mm or more, optionally 3 mm or more, or 5 mm or more. The thickness of the container 20 is, for example, 20 mm or less, optionally 15 mm or less, or optionally 10 mm or less.

[0048] The drift electrode 40, the electron detector 30, and the radiation detector 50 are arranged in this order from the first section 21 toward the second section 22. That is, the drift electrode 40 is located closer to the first section 21 than the electron detector 30. The radiation detector 50 is located closer to the second section 22 than the electron detector 30. "Component A is located closer to the first section 21 than component B" means that component A is located on the side indicated by arrow S1 in FIG. 1 relative to component B. Arrow S1 indicates the direction from the second section 22 toward the first section 21. The distance from component B to the first section 21 may be longer or shorter than the distance from component B to component A.

[0049] The drift electrode 40 may be closer to the first section 21 than to the second section 22. The electron detector 30 and the radiation detector 50 may be closer to the second section 22 than to the first section 21.

[0050] The radiation detector 50 may be located outside the container 20. For example, the radiation detector 50 may be located outside the second section 22. The radiation detector 50 may face the drift electrode 40 with the second section 22 interposed therebetween.

[0051] Although not shown, the radiation detector 50 may be located inside the container 20. For example, the radiation detector 50 may be located between the second portion 22 and the electron detector 30.

[0052] The electron detector 30, the drift electrode 40 and the radiation detector 50 will now be described in detail.

[0053] When radiation entering the container 20 collides with the gas, Compton scattering may occur. When Compton scattering occurs, recoil electrons are generated. Furthermore, ionization electrons are generated along the trajectories of the recoil electrons. The electron detector 30 detects the ionization electrons. By detecting the ionization electrons, the trajectories and energy of the recoil electrons can be calculated.

[0054] FIG. 2 is a perspective view showing an example of an electron detector 30. The electron detector 30 includes a plurality of electrodes. Electrons generated by Compton scattering reach some of the plurality of electrodes. Some of the electrodes generate analog signals as the electrons reach them. By identifying some of the electrodes that generated the analog signals, information regarding the positions on the electron detector 30 at which the electrons reached can be obtained. Information regarding the energy of the electrons that reached the electron detector 30 can be obtained based on the intensity of the analog signals. The intensity of the analog signals is calculated based on the voltage, amplitude, etc. of the analog signals. For example, the voltage or amplitude of the analog signals may be used as the intensity of the analog signals.

[0055] The multiple electrodes of the electron detector 30 may include multiple anode electrodes 31, multiple cathode electrodes 32, and a substrate 35. The substrate 35 includes a first surface 351 and a second surface 352 extending in a direction intersecting the first direction D1. The first surface 351 faces the drift electrode 40. The second surface 352 is located on the opposite side of the first surface 351.

[0056] The plurality of cathode electrodes 32 may be located on the first surface 351. The plurality of cathode electrodes 32 may be aligned in a second direction D2 perpendicular to the first direction D1. Each cathode electrode 32 may extend in a third direction D3 perpendicular to the first direction D1 and the second direction D2.

[0057] The multiple anode electrodes 31 may be located on the second surface 352 and include multiple line portions 311 aligned in the third direction D3. Each line portion 311 may extend in the second direction D2. FIG. 3 is a cross-sectional view showing an example of the electron detector 30. Each line portion 311 may be connected to multiple through portions 312 aligned in the second direction D2 and penetrating the substrate 35. The surface of the through portion 312 may be located in an opening 33 formed in the cathode electrode 32.

[0058] Electrons generated by Compton scattering reach some of the anode electrodes 31 among the multiple anode electrodes 31 and some of the cathode electrodes 32 among the multiple cathode electrodes 32. Some of the anode electrodes 31 generate an anode analog signal as the electrons arrive. By identifying some of the anode electrodes 31 that generated the anode analog signal, information regarding the position in the third direction D3 of the electrons that reached the electron detector 30 can be obtained. Some of the cathode electrodes 32 generate a cathode analog signal as the electrons arrive. By identifying some of the cathode electrodes 32 that generated the cathode analog signal, information regarding the position in the second direction D2 of the electrons that reached the electron detector 30 can be obtained. In this way, the electron detector 30 shown in FIGS. 2 and 3 can efficiently provide information regarding the position in the second direction D2 and the third direction D3 of the electrons that reached the electron detector 30.

[0059] The electron detector 30 may be provided with a second readout circuit 130 (described later) for processing the analog signal. The second readout circuit 130 may be provided in a member separate from the electron detector 30. In this case, the electron detector 30 may be provided with a cable, a hermetic connector, and a wiring board for transmitting the analog signal to the second readout circuit 130.

[0060] The drift electrode 40 is disposed to face the electron detector 30. For example, the drift electrode 40 faces the electron detector 30 in a first direction D1. In this case, the drift electrode 40 includes a surface extending in a direction perpendicular to the first direction D1. Between the electron detector 30 and the drift electrode 40, an electric field is generated from the electron detector 30 toward the drift electrode 40. Ionization electrons accompanying recoil electrons generated by Compton scattering are attracted toward the electron detector 30 by the electric field.

[0061] The radiation detector 50 detects the scattered radiation. In this embodiment, the radiation scattered between the electron detector 30 and the drift electrode 40 is detected by the radiation detector 50 after passing through the electron detector 30 and the second part 22 of the container. The radiation detector 50 can detect the position and energy of the radiation that reaches the radiation detector 50.

[0062] 4 is a perspective view showing an example of a radiation detector 50. The radiation detector 50 may include a plurality of detection elements 51 and a circuit board 52 that supports the detection elements 51. The plurality of detection elements 51 may be aligned in a direction intersecting the first direction D1. For example, the plurality of detection elements 51 may be aligned in a second direction D2 and a third direction D3 that are perpendicular to the first direction D1.

[0063] Radiation reaches some of the detecting elements 51 out of the multiple detecting elements 51. Some of the detecting elements 51 generate analog signals as the radiation reaches them. By identifying some of the detecting elements 51 that generated the analog signals, information about the position on the radiation detector 50 where the radiation reached can be obtained. Based on the intensity of the analog signals, information about the energy of the radiation that reached the radiation detector 50 can be obtained. The intensity of the analog signals is calculated based on the voltage, amplitude, etc. of the analog signals.

[0064] The detecting element 51 may have any configuration as long as it can detect radiation. For example, the detection element 51 may include a scintillator that is excited by the scattered radiation to emit fluorescence, and a photodetector that detects the fluorescence. The photodetector may include, for example, an avalanche photodiode. The detector element 51 may include a semiconductor detector element for detecting the scattered radiation. The semiconductor detector element may comprise, for example, a semiconductor including zinc cadmium telluride.

[0065] The radiation detector 50 may include a first detection element 51 capable of detecting radiation having an energy within a first range, and a second detection element 51 capable of detecting radiation having an energy within a second range different from the first range. This allows the radiation detector 50 to expand the range of radiation energy that it can detect.

[0066] The radiation detected by the detection element 51 is processed as an electrical signal by the circuit board 52. The circuit board 52 may include circuits, wiring, etc. for processing the electrical signal. The electrical signal may be transmitted to the outside of the container 20 via, for example, a cable, a hermetic connector, a wiring board, etc. (not shown) connected to the circuit board 52.

[0067] The other components of the detection device 10 will now be described.

[0068] 1, the detection device 10 may include an auxiliary drift electrode 70 located between the electron detector 30 and the drift electrode 40. The auxiliary drift electrode 70 is provided to improve the uniformity of the electric field distribution between the electron detector 30 and the drift electrode 40.

[0069] The auxiliary drift electrode 70 may include a plurality of ring electrodes 72. The plurality of ring electrodes 72 are aligned in a direction in which the electron detector 30 and the drift electrode 40 face each other. Each ring electrode 72 includes a first ring surface 73 facing the drift electrode 40 and a second ring surface 74 located on the opposite side of the first ring surface 73.

[0070] An opening 721 may be formed in the ring electrode 72. The opening 721 overlaps with the electron detector 30 in the facing direction. The ring electrode 72 does not have to overlap with the electron detector 30 in the facing direction. The ring electrode 72 may overlap with the drift electrode 40 in the facing direction.

[0071] The auxiliary drift electrode 70 may include a spacer 75 disposed between two adjacent ring electrodes 72 in the opposing direction. The spacer 75 determines the distance between the two adjacent ring electrodes 72 in the opposing direction. The distance is determined depending on the number of ring electrodes 72, the voltage between the electron detector 30 and the drift electrode 40, etc.

[0072] The drift electrode 40 may be attached to an auxiliary drift electrode 70. For example, the auxiliary drift electrode 70 may include a spacer 75 positioned between the drift electrode 40 and the ring electrode 72. The structure including the drift electrode 40 and the plurality of ring electrodes 72 is also referred to as a drift cage 45.

[0073] The auxiliary drift electrode 70 may include a wiring 76 that electrically connects two adjacent ring electrodes 72 in the facing direction. The auxiliary drift electrode 70 may also include a wiring 76 that electrically connects two adjacent drift electrodes 40 and ring electrodes 72 in the facing direction. The auxiliary drift electrode 70 may also include a resistor 77 inserted in the path of the wiring 76. By electrically connecting two adjacent ring electrodes 72, the voltage between the two ring electrodes 72 can be adjusted. This allows the potential of the ring electrodes 72 arranged in the facing direction to be changed in stages. For example, assume that the potential of the drift electrode 40 is −4000 V, the potential of the electron detector 30 is 0 V, and 20 ring electrodes 72 are arranged between the drift electrode 40 and the electron detector 30. In this case, the potential of the multiple ring electrodes 72 arranged from the drift electrode 40 toward the electron detector 30 can be changed in stages, such as −3800 V, −3600 V, −3400 V, and so on. This makes it possible to improve the uniformity of the electric field formed in the space between the drift electrode 40 and the electron detector 30 .

[0074] 1 , the auxiliary drift electrode 70 may be supported by an intermediate substrate 90. The intermediate substrate 90 may support the electron detector 30. For example, the intermediate substrate 90 may include a first substrate 91 that supports the electron detector 30 and a second substrate 92 that supports the auxiliary drift electrode 70. The second substrate 92 may be located between the first substrate 91 and the auxiliary drift electrode 70.

[0075] 1, the detection device 10 may include an electron amplifier 60 located between the electron detector 30 and the drift electrode 40. The electron amplifier 60 is arranged to face the electron detector 30 and the drift electrode 40 in, for example, a first direction D1.

[0076] The electron amplifier 60 is configured to generate avalanche amplification. The electron amplifier 60 includes an electrode having a higher potential than the drift electrode 40. The electron amplifier 60 may include a plurality of through-holes 61 extending therethrough. The electron amplifier 60 may be configured to generate an electric field in the through-holes 61 that is directed toward the drift electrode 40.

[0077] Next, Compton scattering occurring in the detection device 10 will be described. FIG. 5 is a diagram showing an example of Compton scattering. The symbol R1 represents radiation that has passed through the first portion 21 of the container 20 and entered the interior of the container 20. The radiation R1 may be, for example, a charged particle beam (e.g., alpha rays, beta rays, etc.), an uncharged particle beam (e.g., neutrinos, neutron beam, etc.), an electromagnetic wave (e.g., gamma rays, X-rays, etc.), or non-ionizing radiation (e.g., ultraviolet light, etc.). After passing through the drift electrode 40, the radiation R1 reaches the space between the electron detector 30 and the drift electrode 40.

[0078] When radiation R1 collides with a gas, Compton scattering may occur. The symbol P represents the position where scattering occurs. The position P is also referred to as the scattering point. The symbol R2 represents the scattered radiation. The radiation R2 passes through the electron detector 30 and then reaches the radiation detector 50. If the radiation detector 50 is located outside the container 20, the radiation R2 also passes through the second portion 22 of the container 20. The radiation R2 is detected by some of the multiple detection elements 51. For example, the radiation R2 is detected by one detection element 51. This makes it possible to calculate the arrival position and energy of the radiation R2.

[0079] When Compton scattering occurs, recoil electrons are generated. Symbol R3 indicates an electron cloud formed in the trajectory of the recoil electron. Symbol e1 represents an electron located at the starting point of electron cloud R3. Electron e1 may be located at scattering point P. Symbol e2 represents an electron located at the end point of electron cloud R3.

[0080] Each electron in the electron cloud R3 moves toward the electron detector 30 due to the electric field E1. This movement is also called drift. Each electron in the electron cloud R3 that reaches the electron detector 30 is detected by the anode electrode 31 and cathode electrode 32 of the electron detector 30. This makes it possible to calculate the position and energy of each electron in the electron cloud R3. In addition, the trajectory and energy of the recoil electron, as well as the scattering point P, can be calculated.

[0081] The radiation R2 travels from the scattering point P to the radiation detector 50 at approximately the speed of light. The recoil electrons also travel at approximately the speed of light from the position of the electron e1 to the position of the electron e2. On the other hand, the speed V at which the electron cloud R3 travels toward the electron detector 30 is slower than the speed of light. Therefore, each electron in the electron cloud R3 reaches the electron detector 30 after the radiation R2 reaches the radiation detector 50. The time at which each electron in the electron cloud R3 reaches the electron detector 30 varies depending on the distance from each electron to the electron detector 30. In the example shown in FIG. 6, the distance from the electron e2 to the electron detector 30 is shorter than the distance from the electron e1 to the electron detector 30. Therefore, the electron e2 reaches the electron detector 30 before the electron e1.

[0082] In Figure 6, the symbols t0, t1, and t2 enclosed in square frames represent the time when radiation R2 or electrons of electron cloud R3 are generated or reach the positions indicated by the symbols. If the time required for the radiation R2 and recoil electrons to travel is ignored, the time when electron e1 is generated, the time when electron e2 is generated, and the time when radiation R2 reaches the radiation detector 50 are all t0. Electron e1 arrives at the electron detector 30 at time t1, after time t0. Electron e2 arrives at the electron detector 30 at time t2. Time t2 is later than time t0, and time t1 is later than time t2.

[0083] The radiation detector 50 generates an analog signal when it detects radiation R2. The electron detector 30 generates an analog signal when it detects electrons. FIG. 7 is a diagram showing an example of an analog signal W_R2 generated by the radiation detector 50 and an analog signal W_R3 generated by the electron detector. The analog signal of the radiation detector 50 is generated at time t0. Time ΔT2 is the difference between time t0 and time t2. Time ΔT2 corresponds to the time required for electron e2 to travel from the end point of electron cloud R3 to the electron detector 30. Time ΔT1 is the difference between time t0 and time t1. Time ΔT1 corresponds to the time required for electron e1 to travel from the start point of electron cloud R3 to the electron detector 30.

[0084] The longer the distance from the electron cloud R3 to the electron detector 30, the longer the time it takes for the electrons to travel to the electron detector 30. The time required for the electrons to travel is longest when the electrons are generated on the drift electrode 40. The time required for the electrons to travel from the drift electrode 40 to the electron detector 30 is also referred to as the maximum travel time TMAX. The maximum travel time TMAX is determined based on the distance between the drift electrode 40 and the electron detector 30 (also referred to as the drift length) and the electron drift velocity V. The drift velocity V is determined based on the electric field strength, the type of gas in the container 20, the gas pressure, etc. For example, under the following conditions 1 and 2, the maximum travel time TMAX is 10.24 μs. (Condition 1) Drift length: 40 cm, electric field strength: 400 V / cm, Gas type: Mixed gas containing argon and ethane, Gas pressure: 1 atmosphere (Condition 2) Drift length: 60 cm, electric field strength: 600 V / cm, Gas type: tetrafluoromethane, Gas pressure: 3 atmospheres

[0085] The maximum travel time TMAX is, for example, 3 μs or more, or may be 5 μs or more, or may be 7 μs or more, and the maximum travel time TMAX is, for example, 30 μs or less, or may be 20 μs or less, or may be 15 μs or less.

[0086] The maximum transit time TMAX may be measured using an apparatus including an electron detector 30 and a drift electrode 40. FIG. 22 is a diagram showing the configuration of an apparatus for measuring the maximum transit time TMAX. The apparatus includes a container 20, an electron detector 30 and a drift electrode 40 located inside the container 20, and a radiation source 80 located on the outer surface of the first portion 21 of the container 20. The electron detector 30 and the drift electrode 40 face each other in a first direction D1 with a gap H between them. The radiation source 80 is a source of radiation. The radiation source 80 is, for example, a standard gamma-ray source (nuclide: Ba-1133, code number: BA402) from the Japan Radioisotope Association. When Compton scattering occurs inside the container 20 due to radiation from the radiation source 80, recoil electrons are generated, and an electron cloud R3 is formed.

[0087] FIG. 23 is a graph showing the number of electrons detected by the electron detector 30 of the apparatus of FIG. 22. The horizontal axis of the graph in FIG. 23 represents time. The vertical axis of the graph in FIG. 23 represents the number of electrons. Each of the multiple points on the graph in FIG. 23 represents the number of electrons detected at a predetermined sampling frequency. The sampling frequency is, for example, 50 MHz or less. The sampling frequency may be 10 MHz or more and 20 MHz or less.

[0088] As shown in Figure 23, the graph includes a period in which the number of electrons is large and the number is nearly constant. This period corresponds to the maximum migration time TMAX. By identifying the period in which the number of electrons is large and the number is nearly constant, the maximum migration time TMAX can be calculated. The electron drift velocity V is calculated by H / TMAX.

[0089] Next, a description will be given of a circuit for generating data by digitizing the analog signals of the radiation detector 50 and the analog signals of the electron detector 30. Fig. 8 is a diagram showing an example of the circuit.

[0090] The detection device 10 includes at least a first readout circuit 150 and a second readout circuit 130. The first readout circuit 150 and the second readout circuit 130 are capable of communicating with a computer 110. The computer 110 receives digital data transmitted from the first readout circuit 150 and the second readout circuit 130 and processes the digital data. For example, the computer 110 calculates the incident direction of radiation into the container 20 based on the first final data and the second final data described below. When the dimensions of the detection device 10 are negligible compared to the distance from the radiation-emitting source to the detection device 10, as in the case of a celestial body, one incident direction is identified for one radiation source. In this case, the positional relationship between the incident direction of radiation and the corresponding radiation source is imaged. On the other hand, when the dimensions of the detection device 10 are not negligible compared to the distance from the radiation-emitting source to the detection device 10, as in the case of SPECT / PET or BNCT, multiple scattering points are detected for one radiation source, and the incident direction is identified from each scattering point. In this case, the position where the incident directions identified at each scattering point converge is identified as the position of the radiation source and imaged. In this way, the combination of the detection device 10 and the computer 110 can function as a radiation identification device that calculates the incident direction of radiation or images the position of the radiation source. The computer 110 may also image an electron cloud generated within the container 20. In this case, the combination of the detection device 10 and the computer 110 can function as an electron imaging device that images electrons. The computer 110 may be a general-purpose personal computer or a calculation processing module suitable for the detection device 10. SPECT stands for Single Photon Emission Computed Tomography, BNCT stands for Boron Neutron Capture Therapy, and PET stands for Positron Emission Tomography.

[0091] The first readout circuit 150 digitizes the analog signal generated by the radiation detector 50 to generate first data D10. The first data D10 is stored in a first buffer, which will be described later. In response to the input of the first trigger signal TS1, the first readout circuit 150 transmits first final data FD10 to the computer 110. The first final data FD10 includes the first data D10 stored in the first buffer.

[0092] The second readout circuit 130 digitizes the analog signal generated by the electron detector 30 to generate second data D20. The second data D20 is stored in a second buffer, which will be described later. In response to the input of the second trigger signal TS2, the second readout circuit 130 transmits second final data FD20 to the computer 110. The second final data FD20 includes the second data D20 stored in the second buffer.

[0093] As shown in FIG. 8 , the detection device 10 may include a logic circuit 120 connected to the second readout circuit 130. The logic circuit 120 generates a first trigger signal TS1 based on, for example, second data D20 generated by the second readout circuit 130. For example, the first trigger signal TS1 is generated in response to generation of a second hit signal (described later) from the second data D20. The logic circuit 120 may also generate a second trigger signal TS2 based on the second data D20. For example, the second trigger signal TS2 is generated in response to generation of the second hit signal. The logic circuit 120 may be connected to both the first readout circuit 150 and the second readout circuit 130. In this case, the logic circuit 120 may generate trigger signals such as the first trigger signal TS1 and the second trigger signal TS2 based on both the first data D10 and the second data D20.

[0094] 9 is a diagram illustrating an example of the second readout circuit 130 and the logic circuit 120. The second readout circuit 130 may include an anode readout circuit 131 and a cathode readout circuit 132.

[0095] The anode readout circuit 131 digitizes each of the anode analog signals generated by the multiple anode electrodes 31. The digital data generated by the anode readout circuit 131 is also referred to as 21st data D21. The 21st data D21 is part of the second data D20. The 21st data D21 may include a 21st hit signal H21. A "hit signal" is a signal generated by binarizing an analog signal. When the intensity of the analog signal exceeds a threshold, the hit signal indicates a high state. When the intensity of the analog signal is equal to or less than the threshold, the hit signal indicates a low state. The 21st hit signal H21 is a signal generated by binarizing the anode analog signal. The anode readout circuit 131 may transmit the 21st hit signal H21 to the logic circuit 120.

[0096] 9, the second readout circuit 130 may include multiple anode readout circuits 131. The number of anode readout circuits 131 is determined according to the number of anode electrodes 31 of the electron detector 30. For example, if the number of anode electrodes 31 is 256 and one anode readout circuit 131 can process 128 analog signals, the second readout circuit 130 includes two anode readout circuits 131.

[0097] In response to the input of the second trigger signal TS2, the anode readout circuit 131 may transmit the twenty-first final data FD21 to the computer 110. The twenty-first final data FD21 includes the twenty-first data D21. The twenty-first final data FD21 is a part of the second final data FD20.

[0098] The cathode readout circuit 132 digitizes each of the cathode analog signals generated by the multiple cathode electrodes 32. The digital data generated by the cathode readout circuit 132 is also referred to as 22nd data D22. The 22nd data D22 is part of the second data D20. The 22nd data D22 may include a 22nd hit signal H22. The 22nd hit signal H22 is a signal generated by binarizing the cathode analog signal. The cathode electrodes 32 may transmit the 22nd hit signal H22 to the logic circuit 120.

[0099] 9, the second readout circuit 130 may include multiple cathode readout circuits 132. The number of cathode readout circuits 132 is determined according to the number of cathode electrodes 32 of the electron detector 30. For example, if the number of cathode electrodes 32 is 256 and one cathode readout circuit 132 can process 128 analog signals, the second readout circuit 130 includes two cathode readout circuits 132.

[0100] In response to the input of the second trigger signal TS2, the cathode readout circuit 132 may transmit the 22nd final data FD22 to the computer 110. The 22nd final data FD22 includes the 22nd data D22. The 22nd final data FD22 is a part of the second final data FD20.

[0101] A detailed description will be given of the anode readout circuit 131. FIG.

[0102] The anode readout circuit 131 may include multiple amplifiers 1361. Each amplifier 1361 amplifies a corresponding anode analog signal AS. The anode readout circuit 131 may include multiple comparators 1362. Each comparator 1362 may binarize the anode analog signal AS amplified by the corresponding amplifier 1361 to generate the 21st hit signal h21. The anode readout circuit 131 may include an amplifier 1363. The amplifier 1363 adds the multiple anode analog signals AS amplified by the multiple amplifiers 1361. The intensity of the analog signal output from the amplifier 1363 represents the intensity of electrons detected by the anode electrode 31. For example, the waveform of the analog signal output from the amplifier 1363 represents the waveform of electrons detected by the anode electrode 31. The multiple amplifiers 1361, the multiple comparators 1362, and the amplifier 1363 may be configured by the first integrated circuit 136. The first integrated circuit 136 is, for example, an ASIC.

[0103] The anode readout circuit 131 may include an AD converter 137. The AD converter 137 digitizes the analog signal output from the amplifier 1363. The data digitized by the AD converter 137 is also referred to as 21st intensity data W21. The 21st intensity data W21 is part of the 21st data D21. The AD converter 137 may be a flash AD converter. In this case, the analog signal is digitized at high speed. The sampling rate of the AD converter 137 is, for example, 1 MHz or higher, or may be 5 MHz or higher, or 10 MHz or higher. The sampling rate of the AD converter 137 is, for example, 50 MHz or lower, or may be 30 MHz or lower, or may be 20 MHz or lower. Setting a low sampling rate can reduce the amount of data generated by the AD converter 137, thereby reducing the load on the computer 110.

[0104] The anode readout circuit 131 may include a twenty-first buffer 1381 and a twenty-second buffer 1382. Buffers included in the second readout circuit 130, such as the twenty-first buffer 1381 and the twenty-second buffer 1382, are also referred to as second buffers.

[0105] The 21st buffer 1381 and the 22nd buffer 1382 are, for example, ring buffers. The 21st buffer 1381 and the 22nd buffer 1382 store the 21st data D21 therein during the second storage period. The 21st buffer 1381 may temporarily store the 21st hit signal h21. The 21st buffer 1381 may temporarily store the 21st hit signal H21 obtained by processing the multiple 21st hit signals h21 using an OR circuit. The 21st hit signal H21 indicates a High state when at least one of the multiple anode analog signals input to the anode readout circuit 131 is in a High state. The 22nd buffer 1382 may temporarily store the 21st intensity data W21. The second storage period may be equal to or shorter than the above-mentioned maximum transfer time TMAX.

[0106] The anode readout circuit 131 may output the twenty-first hit signal H21 to the logic circuit 120. The anode readout circuit 131 may output the twenty-first hit signal H21 to the logic circuit 120 before it is stored in the twenty-first buffer 1381.

[0107] When the second trigger signal TS2 is input to the anode readout circuit 131, the twenty-first data D21 stored in the twenty-first buffer 1381 and the twenty-second buffer 1382 at that time is output from the twenty-first buffer 1381 and the twenty-second buffer 1382. The anode readout circuit 131 may include a second data processing unit 1383 that processes the output twenty-first data D21. The second data processing unit 1383 generates twenty-first final data FD21 that is sent to the computer 110.

[0108] The twenty-first final data FD21 at least partially includes information of the twenty-first data D21. For example, the twenty-first final data FD21 may include information of the twenty-first hit signal H21. For example, the twenty-first final data D21 may include twenty-first intensity data W21. The format of the information of the twenty-first data D21 included in the twenty-first final data FD21 may be the same as or different from the format of the twenty-first data D21.

[0109] The 21st final data FD21 may include information regarding the time when the 21st data D21 was stored in the 21st buffer 1381 and the 22nd buffer 1382. The 21st final data FD21 may include information regarding the position of the anode electrode 31 at which the electrons were detected. In other words, the 21st final data FD21 may include information regarding the arrival position of the electrons on the electron detector 30.

[0110] The twenty-first buffer 1381, the twenty-second buffer 1382, and the second data processing unit 1383 may be configured by the second integrated circuit 138. The second integrated circuit 138 is, for example, an FPGA.

[0111] The anode readout circuit 131 may output a data collection signal DA21 to the logic circuit 120. The data collection signal DA21 is a signal that goes to a High state when the 21st buffer 1381 and the 22nd buffer 1382 are being written to.

[0112] The configuration of the cathode readout circuit 132 may be the same as the configuration of the anode readout circuit 131 .

[0113] Next, referring back to FIG. 9, the logic circuit 120 will be described.

[0114] When the second readout circuit 130 includes multiple anode readout circuits 131, the logic circuit 120 may include an OR circuit 121, as shown in FIG. 9 . The 21st hit signal H21 from each anode readout circuit 131 is input to the OR circuit 121. The OR circuit 121 processes the multiple 21st hit signals H21 and outputs a 23rd hit signal H23. The 23rd hit signal H23 indicates a high state when at least one of the multiple 21st hit signals H21 is in a high state. That is, the 23rd hit signal H23 indicates a high state when at least one of the multiple anode analog signals generated by the multiple anode electrodes 31 exceeds a threshold. The 23rd hit signal H23 indicates a low state when all of the multiple 21st hit signals H21 are in a low state. That is, the 23rd hit signal H23 indicates a low state when all of the multiple anode analog signals generated by the multiple anode electrodes 31 are equal to or lower than a threshold. Such a 23rd hit signal H23 is also referred to as an anode hit signal.

[0115] When the second readout circuit 130 includes multiple cathode readout circuits 132, the logic circuit 120 may include an OR circuit 122, as shown in FIG. 9 . A 22nd hit signal H22 from each cathode readout circuit 132 is input to the OR circuit 121. Like the 21st hit signal H21, the 22nd hit signal H22 indicates a High state when at least one of the multiple cathode analog signals input to the cathode readout circuit 132 is in a High state. The OR circuit 122 processes the multiple 22nd hit signals H22 and outputs a 24th hit signal H24. The 24th hit signal H24 indicates a High state when at least one of the multiple 22nd hit signals H22 is in a High state. In other words, the 24th hit signal H24 indicates a High state when at least one of the multiple cathode analog signals generated by the multiple cathode electrodes 32 exceeds a threshold. The 24th hit signal H24 indicates a low state when all of the 22nd hit signals H22 are in a low state. That is, the 24th hit signal H24 indicates a low state when all of the cathode analog signals generated by the cathode electrodes 32 are equal to or lower than the threshold. Such a 24th hit signal H24 is also referred to as a cathode hit signal.

[0116] When the second readout circuit 130 includes an anode readout circuit 131 and a cathode readout circuit 132, the logic circuit 120 may include an AND circuit 123, as shown in FIG. 9 . The 23rd hit signal H23 and the 24th hit signal H24 are input to the AND circuit 123. The AND circuit 123 processes the 23rd hit signal H23 and the 24th hit signal H24 to generate a second hit signal H20. The second hit signal H20 indicates a high state when at least one of the multiple anode analog signals from the electron detector 30 exceeds a threshold and at least one of the multiple cathode analog signals from the electron detector 30 exceeds a threshold. The second hit signal H20 indicates a low state when all of the multiple anode analog signals are below the threshold or when all of the multiple cathode analog signals are below the threshold.

[0117] 9, the logic circuit 120 may include a processing circuit 124 to which the second hit signal H20 is input. The processing circuit 124 generates a first trigger signal TS1 when the second hit signal H20 is input. The processing circuit 124 may generate the first trigger signal TS1 immediately when the second hit signal H20 is input. Alternatively, the processing circuit 124 may generate the first trigger signal TS1 after a first delay time DT1 has elapsed since the second hit signal H20 was input. The first delay time DT1 may be equal to or less than the maximum movement time TMAX described above.

[0118] The processing circuit 124 may generate the second trigger signal TS2 after a second delay time DT2 has elapsed since the second hit signal H20 was input. The second delay time DT2 may be equal to or shorter than the maximum travel time TMAX. This prevents the second trigger signal TS2 from being generated before electrons generated at a position far from the electron detector 30 reach the electron detector 30.

[0119] Next, the first readout circuit 150 will be described in detail. Fig. 11 is a diagram showing an example of the configuration of the first readout circuit 150. A plurality of analog signals ES generated by a plurality of detection elements 51 of the radiation detector 50 are input to the first readout circuit 150. The first readout circuit 150 digitizes the plurality of analog signals ES to generate first data D10.

[0120] The first readout circuit 150 may include a plurality of amplifiers that amplify the plurality of analog signals ES, similar to the anode readout circuit 131. The first readout circuit 150 may include a plurality of comparators that binarize the plurality of analog signals ES to generate a plurality of hit signals, similar to the anode readout circuit 131. The first readout circuit 150 may process the plurality of hit signals using an OR circuit to generate the first hit signal H10. The first readout circuit 150 may output the first hit signal H10 to the logic circuit 120. The first hit signal H10 is part of the first data D10. The first hit signal H10 indicates a high state when at least one of the plurality of analog signals generated by the plurality of detection elements 51 exceeds a threshold. The first hit signal H10 indicates a low state when all of the plurality of analog signals generated by the plurality of detection elements 51 are equal to or lower than a threshold.

[0121] The first readout circuit 150 may include an AD converter, similar to the anode readout circuit 131. The AD converter may digitize an analog signal obtained by adding together the multiple analog signals ES. The data digitized by the AD converter is also referred to as first intensity data.

[0122] The first readout circuit 150 may include a first buffer 1561. The first buffer 1561 is, for example, a ring buffer. The first buffer 1561 stores the first data D10 therein for a first storage period. The first storage period may be equal to or shorter than the maximum travel time TMAX described above. When the first trigger signal TS1 is generated after the first delay time DT1 has elapsed since the second hit signal H20 was input, the first storage period may be longer than the maximum travel time TMAX. The first storage period may be shorter than the sum of the first delay time DT1 and the maximum travel time TMAX.

[0123] When the first trigger signal TS1 is input to the first readout circuit 150, the first data D10 stored in the first buffer 1561 at that time is output from the first buffer 1561. The first readout circuit 150 may include a first data processing unit 1562 that processes the output first data D10. The first data processing unit 1562 generates first final data FD1 to be transmitted to the computer 110.

[0124] The first final data FD1 at least partially includes information of the first data D10. For example, the first final data FD10 may include information of the first hit signal H10. For example, the first final data D10 may include first intensity data. The format of the information of the first data D10 included in the first final data FD10 may be the same as or different from the format of the first data D10.

[0125] The first final data FD10 may include information about the time when the first data D10 was stored in the first buffer 1561. The first final data FD10 may include information about the position of the detecting element 51 that detected the radiation. In other words, the first final data FD10 may include information about the position on the radiation detector 50 where the radiation arrived.

[0126] The first buffer 1561, the first data processing unit 1562, etc. may be configured by the integrated circuit 156. The integrated circuit 156 is, for example, an FPGA.

[0127] The first readout circuit 150 may output a data collection signal DA10 to the logic circuit 120. The data collection signal DA10 is a signal that goes to a High state when writing to the first buffer 1561 is being performed.

[0128] Next, the logic circuit 120 will be described with reference to FIG. 9 again. As shown in FIG. 9, a VETO signal VS may be input to the processing circuit 124. The VETO signal VS is a signal that goes high when buffer writing is being performed in the anode readout circuit 131, the cathode readout circuit 132, or the first readout circuit 150. When the VETO signal VS is input, the processing circuit 124 may stop outputting the trigger signals TS1 and TS2. That is, when the VETO signal VS goes high, the processing circuit 124 may set the trigger signals TS1 and TS2 to low. This makes it possible to prevent trigger signals from being input to the anode readout circuit 131, the cathode readout circuit 132, and the first readout circuit 150 while buffer writing is being performed.

[0129] Next, a description will be given of an example of the operation of the detection device 10. FIG.

[0130] When Compton scattering of radiation occurs inside the container 20, recoil electrons and an electron cloud R3 are generated. When the scattered radiation R2 is detected by the radiation detector 50, the first readout circuit 150 generates first data D10. Figure 12 shows a first hit signal H10 of the first data D10. The first data D10 is stored in the first buffer for a first storage period BT1.

[0131] After radiation R2 is detected by radiation detector 50, electrons from electron cloud R3 reach electron detector 30. When the electrons are detected by anode electrode 31 and cathode electrode 32, 21st data D21 and 22nd data D22 are generated. Figure 12 shows the anode hit signal of 21st data D21 and the cathode hit signal of 22nd data D22. The 21st data D21 and 22nd data D22 are stored in the second buffer during a second storage period BT2.

[0132] When both the anode hit signal and the cathode hit signal become high, a second hit signal is generated. When the second hit signal is generated, a first trigger signal TS1 is generated. When the first trigger signal TS1 is input to the first readout circuit 150, the first readout circuit 150 transmits first final data FD10 including the first data D10 to the computer 110.

[0133] 12, a second trigger signal TS2 is generated after a second delay time DT2 has elapsed since the second hit signal was generated. When the second trigger signal TS2 is input to the second readout circuit 130, the second readout circuit 130 transmits second final data FD20 including second data D20 to the computer 110. The second final data FD20 includes second final data FD21 including twenty-first data D21 and twenty-second final data FD22 including twenty-second data D22.

[0134] 12, for the first data D10 that are the first and fifth from the left, a first trigger signal TS1 is generated while the first data D10 are stored in the first buffer. Therefore, the first and fifth first data D10 from the left are transmitted to the computer 110. FIG. 13 is a diagram showing an example of the first final data FD10 and the second final data FD20 transmitted to the computer 110.

[0135] 12, the first trigger signal TS1 is not generated while the first data D10 is stored in the first buffer. This situation can occur when radiation that has not been scattered inside the container 20 reaches the radiation detector 50. This situation can also occur when radiation that has not passed through the container 20 reaches the radiation detector 50. The second to fourth first data D10 from the left are erased without being sent to the computer 110.

[0136] FIG. 14 illustrates another example of signal processing. In the example illustrated in FIG. 14, the first data D10, which is the first data from the left, is accompanied by the generation of the 21st data D21 but not the 22nd data D22. Therefore, the first trigger signal TS1 is not generated while the first data D10 is stored in the first buffer. This situation can occur when the electron energy of the electron cloud R3 is low. When the electron energy is low, it is difficult to accurately calculate the trajectory of the recoil electrons. Therefore, the usefulness of the first data D10 and the second data D20 is low when the electron energy is low. The first data D10, which is the first data from the left, is erased without being transmitted to the computer 110.

[0137] The computer 110 calculates information about the radiation and electrons based on the first final data FD10 and the second final data FD20. For example, the computer 110 may calculate the arrival position of the radiation R2, the energy of the radiation R2, the trajectory of the recoil electrons, the energy of the recoil electrons, the position of the scattering point P, etc. The computer 110 may calculate the incident direction of the radiation that entered the container 20 based on this information. The computer 110 may also image the position of the source of the radiation that entered the container 20.

[0138] According to the present embodiment, first data D10 relating to radiation that does not involve the appropriate generation of electrons inside the container 20 is erased without being transmitted to the computer 110. This reduces the amount of first data D10 transmitted to the computer 110. This reduces the load on the computer 110. For example, the load required for calculation processing, image processing, and the like of the first data D10 is reduced. For example, the load required for communication of the first data D10 is reduced. This allows the computer 110 to prioritize processing of highly useful data. This allows, for example, the direction of incidence of radiation incident on the container 20 to be calculated more quickly than with a conventional computer 110. This reduces the degree of exposure of a patient, for example, when the detection device 10 detects radiation emitted from a radiopharmaceutical inside the patient's body.

[0139] Various modifications can be made to the above-described embodiment. Below, modifications will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the above-described embodiment will be designated by the same reference numerals as those used for the corresponding parts in the first embodiment, and duplicated explanations will be omitted. Furthermore, if it is clear that the effects obtained in the above-described embodiment can also be obtained in the modified embodiment, the explanations may be omitted.

[0140] (First Modification) 15 is a diagram showing an example of signal processing in the first modified example. As shown in FIG. 15, the first trigger signal TS1 and the second trigger signal TS2 may be generated simultaneously in response to the second hit signal. For example, the first delay time DT1 may be the same as the second delay time DT2.

[0141] Also in the example shown in FIG. 15, if the first trigger signal TS1 is generated while the first data D10 is stored in the first buffer, the first final data FD10 is transmitted to the computer 110.

[0142] (Second Modification) FIG. 16 illustrates a second readout circuit 130 and a logic circuit 120 in a second modified example. As shown in FIG. 16, the anode hit signal H23 and the cathode hit signal H24 may be input to an OR circuit 125. The OR circuit 125 processes the 23rd hit signal H23 and the 24th hit signal H24 to generate a second hit signal H20. The second hit signal H20 indicates a high state when at least one of the multiple anode analog signals from the electron detector 30 exceeds a threshold or when at least one of the multiple cathode analog signals from the electron detector 30 exceeds a threshold. The second hit signal H20 indicates a low state when all of the multiple anode analog signals are below a threshold and all of the multiple cathode analog signals are below a threshold. When the second hit signal H20 is input, the processing circuit 124 generates a first trigger signal TS1.

[0143] Fig. 17 is a diagram showing an example of signal processing in the second modified example. When an electron is detected by the anode electrode 31 or the cathode electrode 32, the twentieth data D20 is generated. Fig. 17 shows a second hit signal of the twentieth data D20.

[0144] When the second hit signal is generated, a first trigger signal TS1 is generated. When the first trigger signal TS1 is input to the first readout circuit 150, the first readout circuit 150 transmits first final data FD10 including the first data D10 to the computer 110.

[0145] A second trigger signal TS2 is generated after a second delay time DT2 has elapsed since the second hit signal was generated. When the second trigger signal TS2 is input to the second readout circuit 130, the second readout circuit 130 transmits second final data FD20 including the second data D20 to the computer 110.

[0146] In this modification, the first data D10 relating to radiation that does not involve the generation of electrons inside the container 20 is also erased without being transmitted to the computer 110. This reduces the amount of first data D10 transmitted to the computer 110. This reduces the load on the computer 110. For example, the load required for calculation processing, image processing, and the like of the first data D10 is reduced.

[0147] (Third Modification) Fig. 18 is a perspective view showing an electron detector 30 in a third modified example. As shown in Fig. 18, the electron detector 30 includes a plurality of anode electrodes 31 arranged in a second direction D2 and a third direction D3. The electron detector 30 may also include one cathode electrode facing the plurality of anode electrodes 31.

[0148] 19 is a diagram showing an example of the second readout circuit 130 and the logic circuit 120 in the third modified example. The second readout circuit 130 includes an anode readout circuit 131 but does not include a cathode readout circuit. In this case, the OR circuit 121 may generate the second hit signal H20. The second hit signal H20 indicates a high state when at least one of the multiple anode analog signals from the electron detector 30 exceeds a threshold. The second hit signal H20 indicates a low state when all of the multiple anode analog signals are equal to or lower than the threshold.

[0149] An example of signal processing in the third modified example is the same as the example of signal processing in the second modified example shown in Fig. 17. In this modified example as well, the first data D10 relating to radiation that does not involve the generation of electrons inside the container 20 is erased without being transmitted to the computer 110. This reduces the amount of first data D10 transmitted to the computer 110. This reduces the load on the computer 110. For example, the load required for calculation processing, image processing, etc. of the first data D10 is reduced.

[0150] (Fourth Modification) In this modification, a first trigger signal TS1 and a second trigger signal TS2 are generated based on both the first hit signal and the second hit signal. Fig. 20 is a diagram showing a first readout circuit 150, a second readout circuit 130, and a logic circuit 120 in the fourth modification.

[0151] 20 , the detection device 10 may include a plurality of first readout circuits 150. The number of first readout circuits 150 is determined according to the number of detection elements 51 in the radiation detector 50. For example, if the number of detection elements 51 is 64 and one first readout circuit 150 can process 32 analog signals, the detection device 10 includes two first readout circuits 150.

[0152] In response to the input of the first trigger signal TS1, the first readout circuit 150 may transmit eleventh final data FD11 to the computer 110. The eleventh final data FD11 is part of the first final data FD10. The eleventh final data FD11 may include an eleventh hit signal H11. The eleventh hit signal H11 indicates a High state when at least one of the multiple analog signals input to the first readout circuit 150 is in a High state.

[0153] 20, the plurality of eleventh hit signals H11 may be input to an OR circuit 126. The OR circuit 126 outputs a first hit signal H10.

[0154] The logic circuit 120 may include a processing circuit 127 to which the first hit signal H10 is input. The processing circuit 127 outputs a sustain signal H12. The sustain signal H12 indicates a High state for a first sustain period after the first hit signal H10 is generated. The first sustain period is a period for waiting for electrons generated at a position far from the electron detector 30 to reach the electron detector 30. The first sustain period may be equal to or shorter than the above-mentioned maximum travel time TMAX.

[0155] The logic circuit 120 may include a processing circuit 128 to which the 23rd hit signal H23, the 24th hit signal H24, and the sustain signal H12 are input. The processing circuit 128 generates a second hit signal based on the 23rd hit signal H23 and the 24th hit signal H24. For example, similar to the AND circuit 123 described above, the processing circuit 128 may generate the second hit signal when both the anode hit signal H23 and the cathode hit signal H24 are in a high state. Alternatively, similar to the OR circuit 125 of the second modified example described above, the processing circuit 128 may generate the second hit signal when either the anode hit signal H23 or the cathode hit signal H24 is in a high state. The processing circuit 128 generates the hit signal H when the sustain signal H12 is in a high state when the second hit signal is generated.

[0156] The combination of the processing circuits 127 and 128 allows the generation of a hit signal H when a second hit signal is generated within a first sustain period after the generation of the first hit signal H10. The hit signal H is input to the processing circuit 124.

[0157] The processing circuit 124 generates a first trigger signal TS1 when a hit signal H is input. The processing circuit 124 may generate the first trigger signal TS1 immediately when a hit signal H is input. Alternatively, the processing circuit 124 may generate the first trigger signal TS1 after a first delay time DT1 has elapsed since the hit signal H was input. The processing circuit 124 may generate the second trigger signal TS2 after a second delay time DT2 has elapsed since the hit signal H was input.

[0158] 21 is a diagram showing an example of signal processing in the fourth modified example. When scattered radiation R2 is detected by the radiation detector 50, the first readout circuit 150 generates first data D10. FIG. 21 shows a first hit signal H10 of the first data D10. During a first sustain period KT1 after the first hit signal H10 is generated, the sustain signal H12 remains in a High state.

[0159] When a second hit signal is generated during the first sustain period KT1, a first trigger signal TS1 and a second trigger signal TS2 are generated. In the example shown in Fig. 21, for the fourth first data D10 from the left, the twenty-first data D21 and the twenty-second data D22 are generated during the first sustain period KT1, and a second hit signal is generated. Therefore, the fourth first data D10 from the left is transmitted to the computer 110. The twenty-first data D21 and the twenty-second data D22, which are generated in conjunction with the fourth first data D10 from the left, are also transmitted to the computer 110.

[0160] On the other hand, the first data D10 corresponding to the 21st data D21 and 22nd data D22, which are the first data from the left, are not generated. Therefore, the second trigger signal TS2 is not generated. This situation can occur when electrons not caused by Compton scattering are detected by the electron detector 30. The 21st data D21 and 22nd data D22, which are the first data from the left, are erased without being sent to the computer 110.

[0161] According to this modification, the second data D20, such as the 21st data D21 and the 22nd data D22, relating to electrons not resulting from Compton scattering are deleted without being transmitted to the computer 110. This reduces the amount of second data D20 transmitted to the computer 110. This reduces the load on the computer 110. For example, the load required for calculation processing, image processing, and the like of the second data D20 is reduced. For example, the load required for communication of the second data D20 is reduced. This allows the computer 110 to prioritize processing of highly useful data. This allows, for example, the direction of incidence of radiation incident on the container 20 to be calculated more quickly than with the conventional computer 110. This reduces the degree of radiation exposure of the patient, for example, when the detection device 10 detects radiation emitted from a radiopharmaceutical inside the patient's body.

[0162] (Fifth Modification) In the above embodiment, as shown in FIG. 7, a calculation method was described assuming that the analog signal of the radiation detector 50 is generated at time t0. In this modification, as shown in FIG. 24, an example will be described in which the analog signal of the radiation detector 50 is generated a time ΔT3 after time t0. The time ΔT3 may be the difference between the time at which the first hit signal H10 rises and time t0. The first hit signal H10 is obtained by digitizing the analog signal of the radiation detector 50. The time ΔT3 is also referred to as a detection delay time.

[0163] 24 represents the time from when radiation is detected by the radiation detector 50 to when electrons are detected by the electron detector 30. The time ΔT4 may be the difference between the time when the first hit signal H10 rises and the time when the second hit signal H20 rises.

[0164] The time ΔT2 is calculated by adding the time ΔT3 to the time ΔT4. The time ΔT2 corresponds to the time required for the electron e2 to travel from the end point of the electron cloud R3 to the electron detector 30. The time ΔT1 is also calculated taking into account the time ΔT3. The time ΔT1 corresponds to the time required for the electron e1 to travel from the start point of the electron cloud R3 to the electron detector 30. The computer 110 may identify the position of the electron cloud taking into account the time ΔT2 and the time ΔT1. For example, the computer 110 may identify the coordinates of the electrons e1 and e2 in the first direction D1 taking into account the time ΔT2 and the time ΔT1. For example, the computer 110 may image the electron cloud taking into account the time ΔT2 and the time ΔT1.

[0165] The time ΔT3 occurs depending on the radiation detector 50. For example, the time ΔT3 in a radiation detector 50 including a semiconductor detection element may be longer than the time ΔT3 in a radiation detector 50 including a scintillator.

[0166] The computer 110 may obtain information about the time ΔT3 from the radiation detector 50. For example, the radiation detector 50 may transmit a signal in which information including the time ΔT3 has been digitized to the computer 110. The computer 110 may calculate the information about the time ΔT3 based on the analog signal of the radiation detector 50.

[0167] If the radiation detector 50 includes a semiconductor detection element, there may be some relationship between the time ΔT3 and the intensity of the analog signal. The semiconductor detection element includes a cathode electrode and an anode electrode. After radiation R2 passes through the cathode electrode, electrons are generated at a position between the cathode electrode and the anode electrode. If the energy of radiation R2 is low, electrons are generated at a position far from the anode electrode. In this case, the electrons travel a long distance to reach the anode electrode, so the time ΔT3 is long. Furthermore, since the energy of radiation R2 is low, the intensity of the analog signal is also small. On the other hand, if the energy of radiation R2 is high, electrons are generated at a position close to the anode electrode. In this case, the electrons travel a short distance to reach the anode electrode, so the time ΔT3 is short. Furthermore, since the energy of radiation R2 is high, the intensity of the analog signal is also large. The time ΔT3 can be calculated based on the intensity of the analog signal.

[0168] (Sixth Modification) In the above-described embodiment, an example has been shown in which the first trigger signal TS1 is generated starting from a signal from the electron detector 30. For example, in Figures 12, 14, 17, and 21, an example has been shown in which the first trigger signal TS1 is generated when a second hit signal is generated. For example, in Figure 15, an example has been shown in which the first trigger signal TS1 is generated after the first delay time DT1 has elapsed since the second hit signal was generated. In this modification, an example will be described in which the first trigger signal TS1 is generated starting from a signal from the radiation detector 50.

[0169] 25 is a diagram showing signal processing in Modification 6. The first trigger signal TS1 may be generated after a first delay time DT1 has elapsed since the first hit signal H10 of the first data was generated.

[0170] The first delay time DT1 may be the same as the maximum travel time TMAX described above. The first delay time DT1 may be substantially the same as the maximum travel time TMAX described above. "Substantially the same" means that the first delay time DT1 is 0.90 to 1.00 times the maximum travel time TMAX. The first delay time DT1 may be 0.45 to 1.00 times the maximum travel time TMAX.

[0171] The first trigger signal TS1 may be generated only after the first delay time DT1 has elapsed since the first hit signal H10 was generated and only if it is confirmed that the second hit H20 has been generated during the first delay time DT1. In other words, if the second hit H20 has not been generated during the first delay time DT1, the first trigger signal TS1 may not be generated after the first delay time DT1 has elapsed since the first hit signal H10 was generated.

[0172] 25, the second trigger signal TS2 may also be generated after the first delay time DT1 has elapsed since the first hit signal H10 was generated. The second trigger signal TS2 may be generated only after the first delay time DT1 has elapsed since the first hit signal H10 was generated and only if it is confirmed that the second hit H20 has been generated during the first delay time DT1. In other words, if the second hit H20 has not been generated during the first delay time DT1, the second trigger signal TS2 may not be generated after the first delay time DT1 has elapsed since the first hit signal H10 was generated.

[0173] FIG. 26 shows an example of a method for calculating the time ΔT2. After the first trigger signal TS1 is generated, the time ΔT5 is calculated. The time ΔT5 is the difference between the time when the second hit H20 rises and the time when the first trigger signal TS rises. The time ΔT2 is calculated by subtracting the time ΔT5 from the sum of the time ΔT3 and the first delay time DT1.

[0174] (supplement) As in the above-described embodiment and each modified example, "generating a hit signal" may mean "setting the hit signal to a high state." Similarly, "generating a trigger signal" may mean "setting the trigger signal to a high state." Note that, when the circuit of the detection device 10 performs some operation in response to the input of a low-state signal, "generating a signal that generates a hit signal" may mean "setting the hit signal to a low state." Similarly, "generating a signal that generates a trigger signal" may mean "setting the trigger signal to a low state."

[0175] Although several modifications to the above-described embodiment have been described, it is of course possible to combine a plurality of modifications as appropriate and apply them to the above-described embodiment. [Explanation of symbols]

[0176] 5. Object 10. Detection Device 20 containers 30 Electron Detector 31 Anode electrode 32 cathode electrode 35 Base material 40 Drift electrode 45 Drift Cage 50 Radiation detector 51 Detector element 52 Circuit Board 60 Electronic Amplifier 70 Auxiliary drift electrode 110 Computer 120 Logic Circuits 130 Second readout circuit 131 Anode readout circuit 132 Cathode readout circuit 136 First Integrated Circuit 137 AD converter 138 Second Integrated Circuit 1381 21st Buffer 1382 22nd Buffer 1383 Second Data Processing Section 150 1st readout circuit 156 Integrated Circuits 1561 1st buffer 1562 First Data Processing Section

Claims

1. A detection device for detecting radiation, comprising: a container containing a gas; an electron detector located inside the vessel for detecting electrons generated by Compton scattering and generating an analog signal; a drift electrode facing the electron detector; a radiation detector that detects the radiation scattered by the Compton scattering and generates an analog signal; a first readout circuit that digitizes the analog signal generated by the radiation detector to generate first data and stores the first data in a first buffer; a second readout circuit that digitizes the analog signal generated by the electron detector to generate second data; the first readout circuit transmits first final data including the first data stored in the first buffer to an external computer in response to a first trigger signal generated using the analog signal of the radiation detector as a starting point; The first final data includes information about the time when the first data was stored in the first buffer.

2. the radiation detector includes a plurality of detection elements; The detection device according to claim 1 , wherein the first final data includes information relating to a position on the radiation detector where the radiation arrives.

3. 3. The detection apparatus of claim 2, wherein the first final data includes information regarding the intensity of the analog signal produced by the radiation detector.

4. the first buffer of the first readout circuit holds the first data for a first storage period; the first storage period is less than or equal to a maximum travel time; 2. The detection apparatus of claim 1, wherein the maximum transit time is the time it takes for an electron to travel from the drift electrode to the electron detector.

5. the detection device includes a logic circuit connected to the first readout circuit and the second readout circuit; 5. The detection device according to claim 1, wherein the logic circuit generates the first trigger signal using the analog signal of the radiation detector as a starting point.

6. 5. The detection device according to claim 1, wherein the first trigger signal is generated in response to generation of the second data.

7. the first readout circuit generates a first hit signal when the intensity of the analog signal of the radiation detector exceeds a threshold; 5. The detection device according to claim 1, wherein the first trigger signal is generated after a first delay time has elapsed since the first hit signal was generated.

8. The radiation detector has a detection delay time (ΔT3), The detection device according to any one of claims 1 to 4, wherein the time (ΔT2) required for electrons generated by Compton scattering to travel to the electron detector is calculated based on the detection delay time (ΔT3).

9. 9. The detection device according to claim 8, wherein the time (ΔT2) required for electrons generated by Compton scattering to travel to the electron detector is calculated by adding the detection delay time (ΔT3) to the time (ΔT4) from when radiation is detected by the radiation detector to when electrons are detected by the electron detector.

10. the first readout circuit generates a first hit signal when the intensity of the analog signal of the radiation detector exceeds a threshold; the second readout circuit generates a second hit signal when the intensity of the analog signal of the electron detector exceeds a threshold; 10. The detection device according to claim 9, wherein the time (ΔT4) from when radiation is detected by the radiation detector to when electrons are detected by the electron detector is the difference between the time when the first hit signal rises and the time when the second hit signal rises.

11. the first readout circuit generates a first hit signal when the intensity of the analog signal of the radiation detector exceeds a threshold; the first trigger signal is generated after a first delay time has elapsed since the first hit signal was generated; the second readout circuit generates a second hit signal when the intensity of the analog signal of the electron detector exceeds a threshold; The time (ΔT2) required for the electrons generated by Compton scattering to travel to the electron detector is calculated by subtracting the time (ΔT5) from the sum of the detection delay time (ΔT3) and the first delay time, 9. The detection device according to claim 8, wherein the time (ΔT5) is a difference between a time when the second hit signal rises and a time when the first trigger signal rises.

12. the first delay time is equal to or greater than 0.45 times and equal to or less than 1.00 times the maximum travel time, 8. The detection apparatus of claim 7, wherein the maximum transit time is the time it takes for an electron to travel from the drift electrode to the electron detector.

13. 5. The detection device according to claim 1, wherein the first readout circuit transmits information relating to a detection delay time in the radiation detector to the computer.

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