Radiation detector, method of using the same, and radiation inspection apparatus

Abstract

The application discloses a kind of radiation detector and its use method and radiation inspection device, wherein the radiation detector includes: first active material layer and second active material layer, first active material layer absorbs the part of first energy section in incident radiation, and second active material layer absorbs the part of second energy section in incident radiation;First collecting electrode and second collecting electrode, first collecting electrode is set to the surface of first active material layer away from second active material layer, and second collecting electrode is set to the surface of second active material layer away from first active material layer;First collecting electrode is used to collect carrier in first active material layer when being applied reverse bias, and second collecting electrode is used to collect carrier in second active material layer when being applied reverse bias.The device in the application can distinguish the electrical signal generated by dual-energy radiation photon in the process of once radiation incidence, and realize dual-energy imaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric detection, in particular to a radiation detector and a use method thereof, and a radiation examination device. BACKGROUND

[0002] Radiation examination devices are used in various fields such as medical equipment and industrial non-destructive examination devices. As medical equipment, CT (Computed Tomography) devices and PET (positron emission Tomography) devices can be listed. In addition, as radiation, X-rays, gamma rays, etc. are used.

[0003] There are two types of conventional X-ray detection methods, indirect detection and direct detection. In indirect X-ray detection, X-ray photons are first incident on a scintillator composed of inorganic materials, the scintillator converts X-ray photon energy photons into visible light photons, and then a silicon-based CCD or CMOS image sensor is used to receive visible light photon signals for imaging; direct X-ray detection does not require a scintillator, X-ray photons are directly incident on active materials such as amorphous selenium, due to photoelectric effect and Compton scattering effect, etc. of X-ray photons, the active material will generate photo-generated carriers after absorbing X-ray photons, and the detector obtains the intensity information of X-rays by detecting the electrical signal formed by the photo-generated carriers. Since the electrical signal obtained by indirect X-ray detection cannot directly distinguish the energy of X-ray photons, in recent years, the development of a radiation detector that directly converts the radiation that has passed through the object into an electrical signal is being carried out, and higher requirements are put forward for the electrical signal generated by different energy X-ray photons.

[0004] The double detector scheme currently adopted is to separate low and high energy rays for detection after shaping the X-rays with a filter between the two detectors, and copper and aluminum filters are usually used. However, the energy spectrum distinction of high and low energy rays obtained by using this scheme is not large, so there is a large error in the reconstruction result, which is called "pseudo dual-energy" imaging, and in fact it cannot meet the demand of distinguishing the electrical signal generated by different energy X-ray photons. SUMMARY

[0005] Therefore, the main purpose of the present application is to solve the problem that the existing radiation detector cannot distinguish the electrical signal generated by different energy radiation photons, and to provide a radiation detector, and to correspondingly provide a use method of the radiation detector and a radiation examination device.

[0006] To this end, according to a first aspect, the present application provides a radiation detector, comprising: a first active material layer and a second active material layer, the first active material layer absorbing a portion of a first energy segment of incident radiation, the radiation after passing through the first active material layer being incident on the second active material layer, the second active material layer absorbing a portion of a second energy segment of the incident radiation; the second energy segment being a portion of the radiation higher than the first energy segment, an absorption coefficient of the first active material layer for the radiation of the second energy segment being less than an absorption coefficient of the second active material layer for the radiation of the second energy segment; a first collecting electrode and a second collecting electrode, the first collecting electrode being disposed on a surface of the first active material layer away from the second active material layer, the second collecting electrode being disposed on a surface of the second active material layer away from the first active material layer; the first collecting electrode being configured to collect carriers in the first active material layer when a reverse bias is applied, the second collecting electrode being configured to collect carriers in the second active material layer when a reverse bias is applied.

[0007] Further, a thickness of the second active material layer is greater than a thickness of the first active material layer.

[0008] Further, the thickness of the second active material layer is three times or more than the thickness of the first active material layer.

[0009] Further, the first active material layer is a group III-V semiconductor active material layer, and the second active material layer is a perovskite active material layer.

[0010] Further, the first active material layer is a group III-V semiconductor single-crystal active material layer, and the second active material layer is a perovskite single-crystal active material layer.

[0011] Further, the radiation detector further comprises: a first cover plate and a second cover plate, the first cover plate being disposed on a surface of the first collecting electrode away from the first active material layer, the second cover plate being disposed on a surface of the second collecting electrode away from the second active material layer.

[0012] According to a second aspect, the present application further provides a method for using a radiation detector, comprising the following steps: sequentially applying a first reverse bias on a first collecting electrode in the radiation detector, and applying a second reverse bias on a second collecting electrode; obtaining a first current corresponding to the first reverse bias and a second current corresponding to the second reverse bias; the radiation detector comprises a first active material layer and a second active material layer, the first active material layer absorbs part of a first energy segment in incident radiation, the radiation after passing through the first active material layer is incident on the second active material layer, and the second active material layer absorbs part of a second energy segment in the incident radiation; the second energy segment is part of the radiation higher than the first energy segment, and an absorption coefficient of the first active material layer to the second energy segment of the radiation is less than an absorption coefficient of the second active material layer to the second energy segment of the radiation; the first collecting electrode is arranged on a surface of the first active material layer away from the second active material layer, and the second collecting electrode is arranged on a surface of the second active material layer away from the first active material layer; when the first reverse bias is applied on the first collecting electrode, the first active material layer is in a critical state in which all photo-generated holes therein are collected by the first collecting electrode, and when the second reverse bias is applied on the second collecting electrode, the second active material layer is in a critical state in which all photo-generated holes therein are collected by the second collecting electrode.

[0013] Further, the first reverse bias is calculated according to a hole mobility, a hole lifetime of the first active material layer, and a thickness of the first active material layer; and the second reverse bias is calculated according to a hole mobility, a hole lifetime of the second active material layer, and a thickness of the second active material layer.

[0014] Further, the thickness of the second active material layer is greater than the thickness of the first active material layer.

[0015] According to a third aspect, the present application further provides a radiation inspection device comprising the radiation detector in the first aspect.

[0016] The technical solution provided by the present application has the following advantages:

[0017] 1. The radiation detector provided by the present application, by setting the first active material layer with a smaller absorption coefficient for high-energy parts (parts of the second energy section) of the radiation and the second active material layer with a larger absorption coefficient for high-energy parts (parts of the second energy section) of the radiation, and making the radiation first incident on the first active material layer and then on the second active material layer, so that the first active material layer can first absorb the low-energy components (parts of the first energy section) of the incident radiation, and the second active material layer can absorb the high-energy components of the incident radiation (the low-energy parts of the incident radiation have been absorbed by the first active material layer), and then by setting the first collecting electrode capable of collecting the carriers in the first active material layer when a reverse bias is applied, and the second collecting electrode capable of collecting the carriers in the second active material layer when a reverse bias is applied, the size of the photo-generated hole current of the first active material layer and the second active material layer after being incident on the radiation is obtained respectively, that is, the average energy of the radiation photons of two different energies (the low-energy components absorbed by the first active material layer and the high-energy components absorbed by the second active material layer) is obtained, meeting the needs of distinguishing the electrical signals generated by dual-energy radiation photons using one radiation detector; and then by obtaining two different electrical signals (high-energy part and low-energy part) generated after the radiation passes through the measured object, an image formed by dual-energy radiation photons is obtained, and then the two images are subtracted to realize the image subtraction of the radiation, thereby realizing dual-energy imaging, improving the imaging quality, and the detected person does not need to receive two times of radiation exposure, so that the X-ray dose received by the detected person is halved.

[0018] 2. The radiation detector provided by the present application, by setting the thickness of the second active material layer to be greater than the thickness of the first active material layer, the second active material layer can better absorb high-energy radiation, further improving the accuracy of the electrical signals generated by different energy radiation photons ultimately obtained by the radiation detector, thereby further improving the quality of the radiation image ultimately obtained by the radiation detector.

[0019] 3. The radiation detector provided by the present application, by setting the first cover plate covering the first collecting electrode, and the second cover plate covering the second collecting electrode, the dark current generated by the radiation detector can be reduced, thereby further improving the accuracy of the electrical signals generated by different energy radiation photons ultimately obtained by the radiation detector, further improving the quality of the radiation image ultimately obtained by the radiation detector. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art of the present application, the drawings required to be used in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0021] Figure 1 A structural schematic diagram of a radiation detector provided by an embodiment of the present application;

[0022] Figure 2 The mass attenuation coefficient curves of X-rays of different photon energies for GaN and Cs2AgBiBr6;

[0023] Figure 3 A method flowchart of a method for a use method of a radiation detector provided by an embodiment of the present application;

[0024] 1-first active material layer; 2-second active material layer; 3-first collecting electrode; 4-second collecting electrode; 5-first cover plate; 6-second cover plate. DETAILED DESCRIPTION

[0025] The technical solutions of the present application will be described below in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] In the description of the present application, it should be noted that the positions or location relationships indicated by the terms "upper", "lower" and the like are based on the positions or location relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular position, be constructed and operated in a particular position, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0027] Embodiment 1

[0028] The present embodiment provides a radiation detector, as shown in the figure, which comprises a first active material layer, a second active material layer, a first collecting electrode, a second collecting electrode, a first power supply and a second power supply. Figure 1

[0029] Among them, as shown in the figure, Figure 1 ​As shown, the first active material layer and the second active material layer are both used for incident radiation, and the radiation is incident from the first active material layer and then enters the second active material layer. In this application, the first active material layer and the second active material layer, the first active material layer absorbs part of the first energy segment of the incident radiation, and the radiation after passing through the first active material layer is incident on the second active material layer, and the second active material layer absorbs part of the second energy segment of the incident radiation; the second energy segment is the part of the radiation higher than the first energy segment, and the absorption coefficient of the first active material layer to the second energy segment of the radiation is less than the absorption coefficient of the second active material layer to the second energy segment of the radiation.

[0030] In this embodiment, the radiation can be X-rays or gamma rays, etc.; the following are described using X-rays.

[0031] In this embodiment, the first active material layer is used to absorb the low-energy part of the X-rays (in actual application, the radiation here is the X-rays passing through the measured object or the detected person), and the second active material layer is used to absorb the high-energy part of the X-rays. Specifically, the first active material layer can be a relatively low-absorption-coefficient III-V semiconductor active material layer, which can be specifically selected from, but not limited to, any one of GaN, (InAl)N and (AlGa)N compound systems and GaAs, (InAl)As, (InGa)As and (AlGa)As compound systems, and the second active material layer can be a relatively high-absorption-coefficient halide perovskite or perovskite-like material, which can be specifically selected from, but not limited to, any one of Cs2AgBiBr6, MAPbI3, FAPbI3, CsPbBr3, CsPbI3, CsPbCl3, CsSnI3 or FASnI3.

[0032] Specifically, taking the first active material layer as a GaN layer and the second active material layer as a Cs2AgBiBr6 layer as an example, the curves of the absorption coefficients of the two with respect to photon energy are as shown in Figure 2 Figure 2 The protrusions of the curves at a certain energy correspond to the shell absorption edges of each element), and it can be seen from Figure 2 that in the higher energy range 20keV-100keV (second energy segment) of X-rays, the absorption coefficient of Cs2AgBiBr6 is higher than that of GaN material, so when continuous energy spectrum X-rays are incident from the GaN layer into the detector, the GaN active layer mainly absorbs X-ray components with low energy. After the X-rays with low energy are absorbed, the Cs2AgBiBr6 layer can effectively absorb the high-energy part, and accordingly, the number of photo-generated carriers generated by the Cs2AgBiBr6 layer is higher than that of the GaN material.

[0033] ​In the embodiment, in order to improve the carrier transport efficiency, the product of carrier mobility and lifetime (μ·τ) of the first active material layer and the second active material layer can be improved, and specifically, the first active material layer can be set as a single-crystal active material layer of a group III-V semiconductor.

[0034] In the embodiment, in order to enable the second active material layer to absorb as many high-energy X-rays as possible, thereby improving the accuracy of the electrical signal generated by different energy radiation photons ultimately acquired by the radiation detector, and further improving the quality of the radiation image ultimately acquired by the radiation detector, the second active material layer should have a relatively large thickness, and the first active material layer mainly absorbs low-energy X-ray components, and the thickness thereof can be relatively thin, that is, the thickness of the second active material layer is greater than the thickness of the first active material layer. Exemplarily, the first active material layer can be set to 1 mm (or less than 1 mm), and the second active material layer can be set to 3 mm or more.

[0035] As shown in FIG. 1, the first collecting electrode is arranged on the surface of the first active material layer away from the second active material layer, and the second collecting electrode is arranged on the surface of the second active material layer away from the first active material layer. Figure 1 The first collecting electrode is used to collect carriers in the first active material layer when a reverse bias is applied, and the second collecting electrode is used to collect carriers in the second active material layer when a reverse bias is applied.

[0036] As shown in FIG. 1, the first collecting electrode is arranged on the surface of the first active material layer away from the second active material layer, and the second collecting electrode is arranged on the surface of the second active material layer away from the first active material layer. Figure 1 As shown in FIG. 1, the first collecting electrode is arranged on the surface of the first active material layer away from the second active material layer, and the second collecting electrode is arranged on the surface of the second active material layer away from the first active material layer.

[0037] In the embodiment, the number of photo-generated carriers generated by the first active material layer and the second active material layer is different, and different sizes of photocurrents can be collected, thereby obtaining a detection signal of dual-energy spectrum X-ray photons, and in order to collect different photo-generated carriers of the X-ray detector, different reverse bias voltages can be applied to the two electrodes. Specifically, taking the first active material layer as a group III-V semiconductor active material layer and the second active material layer as a perovskite active material layer as an example, the reverse bias applied to the first collecting electrode (that is, the group III-V semiconductor active material layer) by the first power supply and the reverse bias applied to the second collecting electrode (that is, the perovskite active material layer) by the second power supply are described as follows:

[0038] Since the III-V semiconductor active material layer and the perovskite active material layer generally exhibit n-type semiconductor characteristics, the mobility of photo-generated electrons is much higher than that of photo-generated holes. Thus, when a reverse bias voltage gradually increases from 0, photo-generated electrons are first collected by the collecting electrodes, and photo-generated holes are all recombined in the semiconductor. At this time, the photo-generated current obtained on the collecting electrodes (the first collecting electrode and the second collecting electrode) is mainly contributed by photo-generated electrons. With the gradual increase of the reverse bias voltage, a small number of photo-generated holes close to the collecting electrodes can also be collected by the collecting electrodes. At this time, the size of the photo-generated current includes the contribution of photo-generated electrons and a small number of photo-generated holes. When the reverse bias voltage further increases to a certain value, all photo-generated holes can be collected by the collecting electrodes. At this time, the size of the photo-generated current collected is the result of the joint action of photo-generated electrons and photo-generated holes.

[0039] Therefore, in order to realize X-ray detection with double energy resolution, it is necessary to first determine the sizes of the voltages V1 and V2 applied on the first collecting electrode and the second collecting electrode. V1 is the voltage size that the first collecting electrode needs to apply. When the reverse bias voltage applied by the first collecting electrode is V1, photo-generated holes in the III-V semiconductor active material layer can be collected by the first collecting electrode. In this voltage configuration, the drift length (μ hol ×τ hole ×V1 / d1) of photo-generated holes in the III-V semiconductor active material layer is equal to the thickness d1 of the material layer. At this time, the size of the photo-generated current is mainly contributed by photo-generated electrons in the perovskite single crystal, photo-generated electrons and photo-generated holes in the III-V semiconductor active layer material. Similarly, V2 refers to the voltage size that the second collecting electrode needs to apply. When the reverse bias voltage applied by the second collecting electrode is V2, photo-generated holes in the perovskite active material layer can be collected by the second collecting electrode. In this voltage configuration, the drift length (μ hole ×τ hole ×V2 / d2) of photo-generated holes in the perovskite single crystal is equal to the thickness d2 of the material layer. At this time, the size of the photo-generated current is mainly contributed by photo-generated holes and photo-generated electrons in the perovskite single crystal, and photo-generated electrons in the III-V semiconductor active layer material. At this time, the reverse bias voltage V1 applied by the first collecting electrode and the size V2 of the reverse bias voltage applied by the second collecting electrode can be calculated by the following formula:

[0040] V1=d1 2 / (μ hole1 τ hole1 )

[0041] V2=d2 2 / (μ hole2 τhole2 )

[0042] wherein μ holel and μ hole2 are the hole mobilities of the III-V semiconductor active material layer and the perovskite active material layer, respectively, τ hole1 and τ hole2 are the hole lifetimes of the III-V semiconductor active material layer and the perovskite active material layer, respectively, and d1 and d2 are the thicknesses of the III-V semiconductor active material layer and the perovskite active material layer, respectively. Specifically, the carrier mobility μ holel and μ hole2 of the semiconductor material can be measured by some of the published SCLC (space charge limit current) method or TOF (time of flight) method, and the carrier lifetime τ hole1 and τ hole2 can be measured by the TPV (transient photovoltaic) method or IS (impedance spectroscopy) method.

[0043] The magnitude of the detection current obtained by the radiation detector under the corresponding bias is:

[0044]

[0045]

[0046] wherein I hole1 is the magnitude of the photo-generated hole current inside the III-V semiconductor active material layer, I electron1 is the magnitude of the photo-generated electron current inside the III-V semiconductor active material layer, I hole2 is the magnitude of the photo-generated hole current inside the perovskite active material layer, I electron2 is the magnitude of the photo-generated electron current inside the perovskite active material layer, and and The magnitudes of the two currents represent the detection signal currents generated by X-ray photons of two different average energies E1 and E2, wherein E1 is the average energy of the X-ray photons when the reverse bias V1 is applied on the first collecting electrode, and E2 is the average energy of the X-ray photons when the reverse bias V2 is applied on the second collecting electrode. Specifically, the detection currents and can be obtained by connecting the first collecting electrode and the second collecting electrode to the readout circuit (ROIC) at the back end.

[0047] In the embodiment, when the first active material layer and the second active material layer are other active material layers, the reverse bias to be applied to the first active material layer and the reverse bias to be applied to the second active material layer in the corresponding case can be determined by referring to the above analysis.

[0048] In the radiation detector in the embodiment, the first active material layer and the second active material layer can absorb low-energy components and high-energy components of the incident radiation, respectively, by disposing the first active material layer with a small radiation absorption coefficient and the second active material layer with a large radiation absorption coefficient. Then, the first active material layer and the second active material layer can generate photo-generated hole currents after being irradiated by the radiation, respectively, by disposing the first collecting electrode and the first power supply capable of applying a reverse bias to the first active material layer and the second collecting electrode and the second power supply capable of applying a reverse bias to the second active material layer. In other words, the average energy of the radiation photons of two different energies (the low-energy components absorbed by the first active material layer and the high-energy components absorbed by the second active material layer) can be obtained. The requirement of using one radiation detector to distinguish the electrical signals generated by the dual-energy radiation photons can be met. Then, two different electrical signals (the high-energy part and the low-energy part) generated after the radiation passes through the object to be detected can be obtained to form an image of the dual-energy radiation photons. After that, the image subtraction of the radiation can be realized by subtracting the two images from each other, so that the dual-energy imaging can be realized, the imaging quality can be improved, and the person to be detected does not need to receive two times of radiation exposure, so that the X-ray dose received by the person to be detected is halved.

[0049] As an optional implementation, as shown in Figure 1 As an optional implementation, as shown in

[0050] Embodiment 2

[0051] The embodiment provides a use method of the radiation detector in Embodiment 1, as shown in Figure 3 The method comprises the following steps:

[0052] S10: sequentially applying a first reverse bias to the first collecting electrode in the radiation detector and applying a second reverse bias to the second collecting electrode.

[0053] In the embodiment, the first active material layer is in a critical state in which all the photo-generated holes therein are collected by the first collecting electrode when the first reverse bias is applied to the first collecting electrode, and the second active material layer is in a critical state in which all the photo-generated holes therein are collected by the second collecting electrode when the second reverse bias is applied to the second collecting electrode.

[0054] In the embodiment, the first reverse bias is calculated according to the internal electron mobility, the electron lifetime of the first active material layer, and the thickness of the first active material layer; and the second reverse bias is calculated according to the internal electron mobility, the electron lifetime of the second active material layer, and the thickness of the first active material layer. Specifically, the first reverse bias V1 and the second reverse bias V2 can be calculated by the following formulas:

[0055] V1 = d1 2 / (μ hole1 τ hole1 )

[0056] V2 = d2 2 / (μ hole2 τ hole2 )

[0057] wherein μ hole1 and μ hole2 are the hole mobilities of the first active material layer and the second active material layer respectively, τ hole1 and τ hole2 are the hole lifetimes of the first active material layer and the second active material layer respectively, and d1 and d2 are the thicknesses of the first active material layer and the second active material layer respectively. Specifically, the carrier mobilities μ holel and μ hole2 of the semiconductor material can be measured by some published SCLC (space charge limit current) method or TOF (time of flight) method, and the carrier lifetimes τ hole1 and τ hole2 can be measured by TPV (transient photovoltaic) method or IS (impedance spectroscopy) method.

[0058] And as described in Embodiment 1, the radiation detector in the present embodiment includes a first active material layer and a second active material layer, the first active material layer absorbs part of a first energy section of the incident radiation, the radiation after passing through the first active material layer is incident on the second active material layer, and the second active material layer absorbs part of a second energy section of the incident radiation; the second energy section is part of the radiation higher than the first energy section, the absorption coefficient of the first active material layer to the radiation of the second energy section is less than the absorption coefficient of the second active material layer to the radiation of the second energy section; the first collecting electrode is arranged on the surface of the first active material layer away from the second active material layer, and the second collecting electrode is arranged on the surface of the second active material layer away from the first active material layer.

[0059] S20: Obtain the first current corresponding to the first reverse bias and the second current corresponding to the second reverse bias.

[0060] The specific content of the use method of the radiation detector in the present embodiment can also be understood with reference to the content of Embodiment 1 described above, and will not be repeated here.

[0061] Embodiment 3

[0062] The present embodiment provides a radiation inspection device, which includes the radiation detector in Embodiment 1 described above.

[0063] The radiation inspection device in the present embodiment can also include a radiation generating tube, a controller, a display screen and the like, and the functions and structures of these components all belong to the prior art, and will not be repeated here.

[0064] Obviously, the above embodiments are only examples for clearly illustrating, and not limit the embodiments. For those skilled in the art, on the basis of the above description, other different forms of changes or variations can also be made. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A radiation detector, characterized in that, include: A first active material layer and a second active material layer, wherein the first active material layer absorbs a portion of the first energy segment of the incident radiation, and the radiation after passing through the first active material layer is incident on the second active material layer, wherein the second active material layer absorbs a portion of the second energy segment of the incident radiation. The second energy segment is the portion of the radiation that is higher than the first energy segment. The absorption coefficient of the first active material layer for the radiation in the second energy segment is less than the absorption coefficient of the second active material layer for the radiation in the second energy segment. The first active material layer is a III-V group semiconductor active material layer, and the second active material layer is a perovskite active material layer. A first collecting electrode and a second collecting electrode, wherein the first collecting electrode is disposed on the surface of the first active material layer away from the second active material layer, and the second collecting electrode is disposed on the surface of the second active material layer away from the first active material layer; The first collecting electrode is used to collect carriers in the first active material layer when the first collecting electrode is subjected to a first reverse bias voltage by a first power supply, and the second collecting electrode is used to collect carriers in the second active material layer when the second collecting electrode is subjected to a second reverse bias voltage by a second power supply.

2. The radiation detector according to claim 1, characterized in that, The thickness of the second active material layer is greater than the thickness of the first active material layer.

3. The radiation detector according to claim 2, characterized in that, The thickness of the second active material layer is three times or more than three times the thickness of the first active material layer.

4. The radiation detector according to any one of claims 1-3, characterized in that, The first active material layer is a III-V group semiconductor active material layer, and the second active material layer is a perovskite active material layer.

5. The radiation detector according to claim 1, characterized in that, Also includes: A first cover plate and a second cover plate, wherein the first cover plate is disposed on the surface of the first collecting electrode away from the first active material layer, and the second cover plate is disposed on the surface of the second collecting electrode away from the second active material layer.

6. A method of using a radiation detector, characterized in that, Includes the following steps: A first reverse bias voltage is applied to the first collecting electrode in the radiation detector through a first power supply, and a second reverse bias voltage is applied to the second collecting electrode through a second power supply. Obtain the first current corresponding to the first reverse bias voltage and the second current corresponding to the second reverse bias voltage; The radiation detector includes a first active material layer and a second active material layer. The first active material layer absorbs a portion of the first energy segment of the incident radiation. The radiation after passing through the first active material layer is incident on the second active material layer, and the second active material layer absorbs a portion of the second energy segment of the incident radiation. The second energy range is the portion of the radiation that is higher than the first energy range. The absorption coefficient of the first active material layer for the radiation in the second energy range is less than the absorption coefficient of the second active material layer for the radiation in the second energy range. The first collecting electrode is disposed on the surface of the first active material layer away from the second active material layer, and the second collecting electrode is disposed on the surface of the second active material layer away from the first active material layer. The first active material layer is a III-V group semiconductor active material layer, and the second active material layer is a perovskite active material layer. When the first reverse bias is applied to the first collecting electrode, the first active material layer is in a critical state where all photogenerated holes therein are collected by the first collecting electrode. When the second reverse bias is applied to the second collecting electrode, the second active material layer is in a critical state where all photogenerated holes therein are collected by the second collecting electrode.

7. The method of using the radiation detector according to claim 6, characterized in that, The first reverse bias voltage is calculated based on the hole mobility, hole lifetime, and thickness of the first active material layer; the second reverse bias voltage is calculated based on the hole mobility, hole lifetime, and thickness of the second active material layer.

8. The method of using the radiation detector according to claim 6, characterized in that, The thickness of the second active material layer is greater than the thickness of the first active material layer.

9. A radiation examination device, characterized in that, Includes the radiation detector as described in any one of claims 1-5.

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