A CsI(Tl) scintillator crystal containing multivalent cations to reduce afterglow, and a radiation detection device including the scintillator crystal.

Abstract

This invention provides a scintillation crystal, which may include cesium halide co-doped with thallium and another element. In one embodiment, the scintillation crystal may include CsX:Tl,Me, where X represents a halogen and Me represents a dopant. The dopant is selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er). The dopant concentration of the element selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er) in the scintillation crystal is 1×10⁻⁶. ‑7 The concentration ranges from 0.5 mol% to 0.5 mol%. In a particular embodiment, the scintillation crystal may have a cesium iodide host material, a first dopant comprising thallium cations, and a second dopant comprising cations.

Description

Technical Field

[0001] This disclosure relates to scintillation crystals comprising multivalent cations and radiation detection devices including such scintillation crystals. Background Technology

[0002] Radiation detection devices are used in a variety of applications. For example, scintillators are used in medical imaging and well logging in the oil and gas industry, as well as in environmental monitoring, safety applications, and nuclear physics analysis and applications. CsI:Tl is a scintillation crystal used in radiation detection devices. However, the afterglow problem of CsI:Tl limits the functionality, speed, and accuracy of such devices. Further improvements to CsI:Tl scintillation crystals are needed. Attached Figure Description

[0003] The embodiments are shown by way of example and are not limited to the accompanying drawings.

[0004] Figure 1 An illustration of a radiation detection device according to one embodiment is shown.

[0005] Those skilled in the art will recognize that, for simplicity and clarity, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements in the figures may be enlarged relative to other elements to aid in understanding the embodiments of the invention. Detailed Implementation

[0006] The following description, taken in conjunction with the accompanying drawings, is provided to aid in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of these teachings. This focus is provided to aid in the description of the teachings and should not be construed as a limitation on the scope or applicability of these teachings.

[0007] As used in this paper, the group designations corresponding to columns in the periodic table use the “new notation” standard, as seen in the CRC Handbook of Chemistry and Physics, 81st edition (2000-2001).

[0008] As used herein, the terms "consisting of," "including," "comprises," "have," "possess," or any other variation thereof are intended to cover the meaning of non-exclusive inclusion. For example, a process, method, article, or apparatus that includes a list of features is not necessarily limited to the respective features, but may include other features not expressly listed or inherent to such a process, method, article, or apparatus. Furthermore, unless expressly stated otherwise, "or" means inclusive "or" rather than exclusive "or." For example, any of the following can satisfy condition A or B: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); and both A and B are true (or exist).

[0009] The terms "a" or "an" are used to describe the elements and components described herein. This is done for convenience only and to give a general meaning to the scope of the invention. Unless it is obvious otherwise, this description should be understood to include one or at least one, and the singular includes the plural, or vice versa.

[0010] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Materials, methods, and examples are illustrative rather than limiting. Many details regarding specific materials and processing methods not described herein are conventional and can be found in textbooks and other sources in the field of scintillation and radiation detection.

[0011] This invention provides a scintillation crystal that may include cesium halide co-doped with thallium and another element. Co-doping can reduce afterglow and improve energy resolution, light yield, another suitable scintillation parameter, or any combination thereof. In one embodiment, the scintillation crystal may include CsX:Tl,Me, where X represents a halogen and Me represents an element selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er). The choice of a particular co-dopermeable may depend on the specific scintillation parameter to be changed. As used herein, co-doping may include two or more different elements (Tl and one or more other elements), and a co-dopermeable refers to one or more dopants other than Tl.

[0012] According to certain embodiments, particularly regarding the composition of cesium halide, X may be I or a combination of I and Br. When X is a combination of I and Br, X may comprise at least 50 mol% I, at least 70 mol% I, or at least 91 mol% I. In another embodiment, when X is a combination of I and Br, X may comprise no more than 99 mol% I. It should be understood that the mol% of I in X may be any value between any of the aforementioned minimum and maximum values. It should be further understood that the mol% of I in X may be any value within the range between any of the aforementioned minimum and maximum values.

[0013] According to certain embodiments, particularly regarding the composition of Tl, Tl may comprise a concentration within the scintillation crystal CsX:Tl, Me. In some embodiments, Tl may have a concentration of at least 1 × 10⁻⁶. -4 mol%Tl, at least 1×10 -3 The concentration of Tl is mol%Tl or at least 0.01 mol%Tl. In another embodiment, Tl has a concentration of not more than 10 mol%Tl, not more than 5 mol%Tl, not more than 0.9 mol%Tl, or not more than 0.2 mol%Tl. In a particular embodiment, Tl has a concentration of 1 × 10⁻⁶ mol%Tl. -4 mol% to 10mol%, 1×10 -3 The concentration is in the range of 0.9 mol% or 0.01 mol% to 0.2 mol%. It should be understood that the mol% of Tl in the scintillation crystal can be any value between any of the above minimum and maximum values. It should be further understood that the mol% of Tl in the scintillation crystal can be any value within the range between any of the above minimum and maximum values.

[0014] According to certain embodiments, particularly regarding the composition of Me, Me may include a scintillation crystal CsX:Tl, and the concentration within Me. In one embodiment, when the co-doperb is an element selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er), the dopant concentration of the element selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er) in the scintillation crystal is at least 1 × 10⁻⁶. -7 mol%, at least 1×10 -6 mol%, at least 1×10 -5 mol% or at least 1×10 -4In another embodiment, the concentration of elements selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er) in the scintillation crystal is not greater than 0.5 mol%, such as not greater than 0.3 mol%, not greater than 0.1 mol%, not greater than 0.01 mol%, not greater than 0.003 mol%, or not greater than 0.002 mol% or not greater than 0.001 mol%. In a specific embodiment, the concentration of elements selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er) in the scintillation crystal is 1 × 10⁻⁶. -7 mol% to 0.5 mol%, 1×10 -6 mol% to 0.003 mol%, 1×10 -5 mol% to 0.002 mol% or 1 × 10 -4 mol% to 1×10 -3 Within the mol% range. It should be understood that the mol% of Me in the scintillation crystal can be any value between any of the above minimum and maximum values. It should be further understood that the mol% of Me in the scintillation crystal can be any value within the range between any of the above minimum and maximum values. All the aforementioned dopant concentrations refer to the dopant concentration in the crystal. In a particular embodiment, the co-doperb is a divalent or tetravalent transition metal selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), and cadmium (Cd). In another embodiment, the co-doperb is a trivalent lanthanide rare earth element selected from the group consisting of dysprosium (Dy), thulium (Tm), and erbium (Er). In another embodiment, the co-doperb is a pentavalent transition metal selected from the group consisting of tantalum (Ta). In one embodiment, chromium (Cr), cobalt (Co), manganese (Mn), and cadmium (Cd) may be at least partially in their 2+ oxidation state, wherein the amount of dopant in the scintillator is 1 × 10⁻⁶. -7 Between 0.1 mol% and 0.1 mol%. In another embodiment, the dopant concentration of the element selected from the group consisting of dysprosium (Dy), thulium (Tm), and erbium (Er) can be at least partially in its 3+ oxidation state, wherein the amount of dopant in the scintillator is 1 × 10⁻⁶. -7 Between 0.1 mol% and 0.1 mol%. In another embodiment, the dopant concentration of zirconium (Zr) may be at least partially in its 4+ oxidation state. In yet another embodiment, the dopant concentration of tantalum (Ta) may be at least partially in its 5+ oxidation state.

[0015] According to some embodiments, the concentration of dopant in the crystal may be different from or the same as the concentration of dopant in the melt forming the scintillation crystal. The concentrations of Tl and transition metal co-dopersive agents in the melt during crystal formation may include any of the aforementioned values.

[0016] According to other embodiments, when selecting co-dopers, different considerations may be used to determine which specific elements are more suitable than others for improving a particular scintillation parameter. The following description is intended as general guidance and should not be construed as limiting a particular scintillation parameter to a particular co-dopermeable.

[0017] According to some other embodiments, the light yield of a scintillation crystal with co-doperamide Me can be increased compared to the composition of a scintillation crystal without co-doperamide. In one embodiment, when the light yields of a scintillation crystal with co-doperamide and a CsI:Tl crystal without co-doperamide were measured at 22°C and exposed to gamma radiation with an energy of 662 keV, the light yield of the scintillation crystal with co-doperamide was at least 1%, at least 5%, and at least 10% of the light yield of the CsI:Tl crystal without co-doperamide.

[0018] According to further embodiments, the co-doperamide Me can be used to reduce the afterglow of a scintillation crystal compared to the composition of a scintillation crystal without co-dopersication. In some embodiments, when a scintillation crystal with co-dopersication and a CsI:Tl crystal without co-dopersication are coupled to a silicon photodiode and exposed to an X-ray beam (120 keV, tungsten target), the afterglow of the scintillation crystal with co-dopersication is at least 5% less than that of the CsI:Tl crystal without co-dopersication, such as at least 10%, or at least 20%, or at least 30%, or at least 45%, or at least 50%, or at least 55%. In one embodiment, the scintillation crystal with co-dopersication may have an afterglow that is within a range including any of the minimum and maximum values ​​described above.

[0019] Scintillation crystals can be formed using any of a variety of crystal growth techniques, including Bridgman, Czochralski, Kyropoulos, edge-defined thin-film feed growth (EFG), Stepanov, and gradient-freeze. The starting material comprises cesium halide and a halide dopant. In one embodiment, the starting material may include CsI and TlI, and depending on the co-doperant, the starting material may include any one or more of the following: CrI2, CrI3, ZrI4, CoI2, MnI2, CdI2, DyI3, TmI3, ErI3, TaI5, etc. After determining the desired composition of the scintillation crystal, the amount of starting material to be used in the melt can be determined using the segregation coefficient of the dopant relative to the base material (e.g., CsI). The crystal growth conditions may be the same as those used to form CsI:Tl, or may have relatively small variations to optimize the crystal formation process.

[0020] Any of the scintillation crystals described above can be used in a variety of applications. Exemplary applications include gamma-ray spectroscopy, isotope identification, single-photon emission computed tomography (SPECT) or positron emission tomography (PET) analysis, X-ray imaging, oil well logging tools, and detecting the presence of radioactivity. Scintillation crystals can be used in other applications, and therefore this list is merely exemplary and not limiting. Several specific applications are described below.

[0021] Figure 1 An embodiment of a radiation detection device 100 (such as a single-photon emission computed tomography (SPECT) or a stepper X-ray machine) that can be used for gamma-ray analysis is shown. Figure 1 As shown and according to the embodiments described herein, the radiation detection device 100 may include a photoelectric sensor 101, an optical interface 103, and a scintillation device 105. Although in Figure 1 The photoelectric sensor 101, optical interface 103, and scintillator 105 shown are separate from each other. It should be understood that, according to some embodiments, the photoelectric sensor 101 and scintillator 105 may be coupled to the optical interface 103, wherein the optical interface 103 is disposed between the photoelectric sensor 101 and the scintillator 105. According to other embodiments, the scintillator 105 and the photoelectric sensor 101 may be optically coupled to the optical interface 103 using other known coupling methods, such as using optical gels or adhesives, or directly through molecular adhesion of the optical coupling elements.

[0022] According to some other embodiments, the photoelectric sensor 101 may be a photomultiplier tube (PMT), a semiconductor-based photomultiplier, or a hybrid photoelectric sensor. The photoelectric sensor 101 may receive photons emitted by the scintillation device 105 via an input window 116 and generate electrical pulses based on the number of photons received. The photoelectric sensor 101 is electrically coupled to an electronics module 130. The electronics module 130 may shape, digitize, analyze, or any combination thereof to provide a count or other information of photons received at the photoelectric sensor 101. The electronics module 130 may include an amplifier, a preamplifier, a discriminator, an analog-to-digital converter, a photon counter, a pulse shape analyzer or discriminator, another electronic component, or any combination thereof. The photoelectric sensor 101 may be housed within a tube or housing made of a material (such as a metal, a metal alloy, other materials, or any combination thereof) capable of protecting the photoelectric sensor 101, the electronics module 130, or combinations thereof.

[0023] The scintillation device 105 may include a scintillation crystal 107, which may be any of the aforementioned scintillation crystals represented by the general formula CsX:Tl, Me, where X represents a halogen and Me represents an element selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er). The scintillation crystal 107 is substantially surrounded by a reflector 109. In one embodiment, the reflector 109 may include polytetrafluoroethylene (PTFE), another material adapted to reflect light emitted by the scintillation crystal 107, or a combination thereof. In an illustrative embodiment, the reflector 109 may be substantially surrounded by a damping member 111. The scintillation crystal 107, the reflector 109, and the damping member 111 may be housed within a housing 113.

[0024] The scintillation device 105 may include at least one stabilization mechanism adapted to reduce relative movement between the scintillation crystal 107 and other elements of the radiation detection device 100, such as the optical interface 103, housing 113, damping member 111, reflector 109, or any combination thereof. The stabilization mechanism may include a spring 119, an elastomer, another suitable stabilization mechanism, or a combination thereof. The stabilization mechanism may be adapted to apply lateral forces, horizontal forces, or combinations thereof to the scintillation crystal 107 to stabilize the position of the scintillation crystal relative to one or more other elements of the radiation detection device 100.

[0025] like Figure 1As shown, optical interface 103 may be adapted to couple between photoelectric sensor 101 and scintillation device 105. Optical interface 103 may also be adapted to facilitate optical coupling between photoelectric sensor 101 and scintillation device 105. Optical interface 103 may comprise a polymer such as silicone rubber, which is polarized to calibrate the reflectivity of scintillation crystal 107 and input window 116. In other embodiments, optical interface 103 may comprise a gel or colloid comprising a polymer and additional elements.

[0026] Many different aspects and embodiments are possible. Some of these aspects and embodiments are described herein. After reading this specification, those skilled in the art will understand that those aspects and embodiments are merely illustrative and do not limit the scope of the invention. Various embodiments can be based on any one or more of the items listed below.

[0027] Example 1. A scintillator crystal may include: a cesium iodide host material; a first dopant containing thallium cations, the molar concentration of the first dopant being less than 10%; and a second dopant selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er), wherein the dopant concentration of the element selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er) is at least partially in its 3+ or 2+ or 4+ or 5+ oxidation state, wherein the amount of the second dopant in the scintillator is 1 × 10⁻⁶. -7 Between 0.1 mol% and 0.1 mol%.

[0028] Example 2. The scintillator crystal according to Example 1 may further include a third dopant, wherein the third dopant comprises a trivalent or pentavalent oxide state.

[0029] Example 3. The scintillator crystal according to Example 1, the scintillator crystal further includes a third dopant, wherein the second dopant comprises a tetravalent oxide state and the third dopant comprises a divalent oxide state.

[0030] Example 4. The scintillator crystal according to Example 1, wherein the second dopant selected from the group consisting of chromium (Cr), cobalt (Co), manganese (Mn) and cadmium (Cd) is at least partially in its 2+ oxidation state.

[0031] Example 5. The scintillator crystal according to Example 1, wherein the second dopant selected from the group consisting of dysprosium (Dy), thulium (Tm) and erbium (Er) is at least partially in its 3+ oxidation state.

[0032] Example 6. The scintillator crystal according to Example 1, wherein the second dopant selected from the group consisting of zirconium (Zr) is at least partially in its 4+ oxidation state.

[0033] Example 7. The scintillator crystal according to Example 1, wherein the second dopant selected from the group consisting of tantalum (Ta) is at least partially in its 5+ oxidation state.

[0034] Example 8. A scintillator crystal according to Example 1, wherein the scintillator crystal comprises at least 9 × 10 - 4 mol% of the second dopant.

[0035] Example 9. A scintillator crystal according to Example 1, wherein the scintillator crystal contains less than 1 × 10 - 3 The second dopant is mol%, and the scintillator crystal has a light output intensity of less than 0.5% mol% relative to the light output intensity measured during X-ray irradiation 100 ms after exposure to X-ray irradiation.

[0036] Example 10. The scintillator crystal according to Example 1, wherein the scintillator crystal may contain less than 1 × 10 - 3 The second dopant is mol% and the scintillator crystal has a light output intensity of less than 0.3% at 500 ms after exposure to X-rays, relative to the light output intensity measured during X-ray irradiation.

[0037] Example 11. A scintillator crystal according to Example 1, wherein the scintillator crystal contains a mass greater than 1 × 10⁻⁶ that can exist in more than one oxidation state within the crystal matrix. -6 mol% of co-doped cations.

[0038] Example 12. The scintillator crystal according to Example 1, wherein the scintillator crystal may contain no more than 0.003 mol% of a second dopant.

[0039] Example 13. A scintillator crystal, the scintillator crystal comprising: a cesium iodide host material; a first dopant comprising thallium cations, the first dopant having a molar concentration of less than 10%; and a second dopant comprising chromium cations, the second dopant causing the scintillator to have reduced afterglow.

[0040] Example 14. The scintillator crystal according to Example 13, wherein the amount of chromium in the scintillator crystal can be 1×10⁻⁶. -7 mol% and 1×10 -3 Between mol% chromium.

[0041] Example 15. The scintillator crystal according to Example 13, wherein the scintillator crystal may contain at least 1×10 -7 mol% chromium.

[0042] Example 16. The scintillator crystal according to Example 13, wherein the scintillator crystal contains less than 1 × 10 - 3 The scintillator crystal contains mol% chromium and has a light output intensity of less than 0.3% relative to the light output intensity measured during X-ray irradiation, 100 ms after exposure to X-ray irradiation.

[0043] Example 17. The scintillator crystal according to Example 13, wherein the scintillator crystal contains less than 1 × 10 - 3 The scintillator crystal contains mol% chromium and has a light output intensity of less than 0.2% at 500 ms after exposure to X-rays, relative to the light output intensity measured during X-ray irradiation.

[0044] Example 18. A scintillator crystal according to Example 13, wherein the scintillator crystal contains a mass greater than 1 × 10⁻⁶ that can exist in more than one oxidation state within the crystal matrix. -7 mol% of co-doped cations.

[0045] Example 19. The scintillator crystal according to Example 13, wherein the scintillator crystal may include a second dopant of no more than 0.01 mol%.

[0046] Example 20. A scintillator crystal, the scintillator crystal comprising: a cesium iodide host material; a first dopant comprising a thallium cation, the first dopant having a molar concentration of less than 10%; and a second dopant comprising a zirconium cation, the second dopant causing the scintillator to have reduced afterglow.

[0047] Example 21. The scintillator crystal according to Example 20, wherein the amount of zirconium in the scintillator crystal may include 1 × 10⁻⁶. -7 mol% and 1×10 -3 Between mol% zirconium.

[0048] Example 22. The scintillator crystal according to Example 20, wherein the scintillator crystal may include at least 1×10 -7 mol% Zirconium.

[0049] Example 23. The scintillator crystal according to Example 20, wherein the scintillator crystal may include less than 1 × 10 -3The scintillator crystal has a light output intensity of less than 0.16% mol% relative to the light output intensity measured during X-ray irradiation, 100 ms after exposure to X-ray irradiation.

[0050] Example 24. The scintillator crystal according to Example 20, wherein the scintillator crystal may include less than 1 × 10 -3 The scintillator crystal has a light output intensity of less than 0.1% at 500 ms after exposure to X-rays, relative to the light output intensity measured during X-ray irradiation.

[0051] Example 25. A scintillator crystal according to Example 20, wherein the scintillator crystal comprises a mass greater than 1 × 10⁻⁶ that can exist in more than one oxidation state within the crystal matrix. -7 mol% of co-doped cations.

[0052] Example 26. The scintillator crystal according to Example 20, wherein the scintillator crystal may include a second dopant of no more than 0.01 mol%.

[0053] Example 27. A scintillator crystal according to Example 20, wherein the second dopant is in a tetravalent state.

[0054] Example 28. A radiation detection device, the radiation detection device may include a housing; a scintillator within the housing, the scintillator comprising: a cesium iodide host material; a first dopant comprising thallium cations, the first dopant having a molar concentration of less than 10%; and a second dopant selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er), the dopant concentration of which is selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er), the second dopant causing the scintillator to have afterglow.

[0055] Example 29. The radiation detection device according to Example 28, wherein the scintillator crystal may include a second dopant of no more than 0.01 mol%.

[0056] Example 30. The radiation detection device according to Example 28, wherein the radiation detection device is capable of inspecting more than 300 bags per hour during X-ray irradiation.

[0057] Example 31. The radiation detection device according to Example 28, wherein the radiation detection device is capable of inspecting more than 1,000 bags per hour during computed tomography irradiation.

[0058] Example 32. The radiation detection device according to Example 28, wherein the afterglow is reduced by at least 20%.

[0059] Example

[0060] The concepts described herein will be further illustrated by examples, which do not limit the scope of the invention as claimed. These examples demonstrate the performance of scintillation crystals with different compositions. For convenience, the numerical values ​​disclosed in this example may be averaged, approximated, or rounded from multiple readings. Samples were formed using the vertical Bridgman crystal growth technique.

[0061] Scintillation crystal samples S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, and S17 were formed to compare the afterglow of the co-doped samples with the CsI:Tl standard CS1. The composition of the scintillation crystal samples is listed in Table 1. Further, each sample CS1, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, and S17 was tested to determine the afterglow (AG) and relative light yield. CS1, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, and S12 contain approximately 0.4 mol% Tl. For afterglow measurements, the sample was coupled to a silicon photodiode and exposed to an X-ray beam (120 keV, tungsten target). The photodiode signal was sampled at 100 ms and 500 ms after the X-ray beam was turned off. The ratio of these signal intensities to the signal intensity during X-ray beam exposure was defined as afterglow (AG). Relative light yield was tested at room temperature (approximately 22 °C) by exposing the scintillation crystal to 137Cs and obtaining the spectrum using a photomultiplier tube and a multichannel analyzer. Table 1 also lists the performance test results for scintillation crystal samples CS1, S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, and S17.

[0062] Table 1 - Composition and Properties of Standards and Co-dopersants

[0063]

[0064] As shown in the table, the co-doped samples exhibit lower afterglow compared to the undoped samples, while the light yield of the undoped samples remains in the range of 60% to 100%. Advantageously, a small amount of co-doperant, as described in detail above, is required to demonstrate the reduction in afterglow. Compared to the undoped samples, scintillation crystal S1 shows a reduction in afterglow of at least 77% at 100 ms and at least 80% at 500 ms. Compared to the undoped samples, scintillation crystal S2 shows a reduction in afterglow of at least 62% at 100 ms and at least 70% at 500 ms. Compared to the undoped samples, scintillation crystal S3 shows a reduction in afterglow of at least 72% at 100 ms and at least 80% at 500 ms. Compared to the undoped samples, scintillation crystal S4 shows a reduction in afterglow of at least 30% at 100 ms and at least 37.5% at 500 ms. Compared to the undoped sample, scintillation crystal S5 showed a reduction of at least 55% in afterglow at 100 ms and at least 67.5% at 500 ms. Compared to the undoped sample, scintillation crystal S6 showed a reduction of at least 73% in afterglow at 100 ms and at least 75% at 500 ms. Compared to the undoped sample, scintillation crystal S7 showed a reduction of at least 65% in afterglow at 100 ms and at least 75% at 500 ms. Compared to the undoped sample, scintillation crystal S8 showed a reduction of at least 62% in afterglow at 100 ms and at least 70% at 500 ms. Compared to the undoped sample, scintillation crystal S9 showed a reduction of at least 72% in afterglow at 100 ms and at least 82.5% at 500 ms. Compared to the undoped sample, scintillation crystal S10 showed a reduction of at least 68% in afterglow at 100 ms and at least 75% at 500 ms. Compared to the undoped sample, scintillation crystal S11 showed a reduction of at least 38% in afterglow at 100 ms and at least 60% at 500 ms. Compared to the undoped sample, scintillation crystal S12 showed a reduction of at least 67% in afterglow at 100 ms and at least 72.5% at 500 ms. Compared to the undoped sample, scintillation crystal S13 showed a reduction of at least 70% in afterglow at 100 ms and at least 72.5% at 500 ms. Compared to the undoped sample, scintillation crystal S14 showed a reduction of at least 53% in afterglow at 100 ms and at least 57.5% at 500 ms. Compared to the undoped sample, scintillation crystal S15 showed a reduction of at least 65% in afterglow at 100 ms and at least 77.5% at 500 ms. Compared to the undoped sample, scintillation crystal S16 showed a reduction of at least 43% in afterglow at 100 ms and at least 55% at 500 ms. Compared to the undoped sample, the scintillation crystal S17 showed a reduction of at least 82% in afterglow at 100 ms and at least 87% at 500 ms.

[0065] It should be noted that not all of the behaviors described in the general description of the examples are necessary, and some specific behaviors may not be required. Furthermore, one or more further behaviors may be performed in addition to those described. Also, the order of the listed behaviors is not necessarily the order in which they are performed.

[0066] For clarity, certain features described herein in the context of individual embodiments may also be provided in combination in a single embodiment. Conversely, various features described for simplicity in the context of a single embodiment may also be provided individually or in any sub-combination. Furthermore, references to values ​​expressed as ranges include each value within that range and all values ​​therein.

[0067] The benefits, other advantages, and solutions to the problems have been described above with reference to specific embodiments. However, the benefits, advantages, solutions to the problems, and any features that may make any benefit, advantage, or solution conceived or more significant are not considered critical, required, or necessary features of any or all claims.

[0068] The description and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of various embodiments. The description and illustrations are not intended to be an exhaustive and comprehensive description of all elements and features of apparatuses and systems using the structures or methods described herein. Individual embodiments may also be provided in combination in a single embodiment, and conversely, various features described in the context of a single embodiment for the sake of brevity may also be provided individually or in any sub-combination. Further, references to values ​​expressed as ranges include each and all values ​​within that range. Many other embodiments will only become apparent to those skilled in the art after reading this specification. Other embodiments can be utilized and derived from this disclosure, allowing structural substitutions, logical substitutions, or other changes to be made without departing from the scope of this disclosure. Therefore, this disclosure should be considered illustrative rather than restrictive.

Claims

1. A scintillator crystal, the scintillator crystal comprising: Cesium iodide as the main material; The first dopant contains a thallium cation and the molar concentration of the first dopant is less than 10%. and The second dopant is selected from the group consisting of chromium (Cr), zirconium (Zr), cobalt (Co), manganese (Mn), cadmium (Cd), dysprosium (Dy), thulium (Tm), tantalum (Ta), and erbium (Er). The second dopant is at least partially in its 3+, 2+, 4+, or 5+ oxidation state, wherein the amount of the second dopant in the scintillator is 1 × 10⁻⁶. -7 Between 0.1 mol% and 0.1 mol%, wherein the scintillator crystal has a light output intensity of less than 0.3% 500 ms after exposure to the X-rays, relative to the light output intensity measured during X-ray irradiation.

2. The scintillator crystal according to claim 1, wherein the scintillator crystal further comprises a third dopant, and wherein the second dopant comprises a trivalent oxide state and the third dopant comprises a divalent oxide state.

3. The scintillator crystal according to claim 1, wherein the second dopant, selected from the group consisting of chromium (Cr), cobalt (Co), manganese (Mn) and cadmium (Cd), is at least partially in its 2+ oxidation state.

4. The scintillator crystal according to claim 1, wherein the second dopant, selected from the group consisting of dysprosium (Dy), thulium (Tm) and erbium (Er), is at least partially in its 3+ oxidation state.

5. The scintillator crystal according to claim 1, wherein the second dopant selected from the group consisting of zirconium (Zr) is at least partially in its 4+ oxidation state.

6. The scintillator crystal according to claim 1, wherein the second dopant selected from the group consisting of tantalum (Ta) is at least partially in its 5+ oxidation state.

7. The scintillator crystal according to claim 1, wherein the scintillator crystal comprises at least 9 × 10 -4 The second dopant is mol% and not more than 0.1 mol%.

8. The scintillator crystal according to claim 1, wherein the scintillator crystal comprises less than 1 × 10 -3 The second dopant is mol% and the scintillator crystal has a light output intensity of less than 0.5% 100 ms after exposure to the X-ray irradiation, relative to the light output intensity measured during X-ray irradiation.

9. The scintillator crystal according to claim 1, wherein the scintillator crystal comprises less than 1 × 10⁻⁶ -3 mol% of second dopant.

10. The scintillator crystal of claim 1, wherein the scintillator crystal comprises a crystal matrix containing more than 1 × 10⁻⁶ particles capable of existing in more than one oxidation state within the crystal matrix. -6 mol% of co-doped cations.

11. A scintillator crystal, the scintillator crystal comprising: Cesium iodide as the main material; The first dopant contains a thallium cation and the molar concentration of the first dopant is less than 10%. and The second dopant, which is a chromium cation, causes the scintillator to have reduced afterglow, wherein the scintillator crystal has less than 0.3% light output intensity 500 ms after exposure to the X-rays, relative to the light output intensity measured during X-ray irradiation.

12. The scintillator crystal according to claim 11, wherein the amount of chromium in the scintillator crystal is 1 × 10⁻⁶. - 7 mol% and 1×10 -3 Between mol% chromium.

13. The scintillator crystal of claim 11, wherein the scintillator crystal comprises less than 1 × 10⁻⁶ -3 The chromium content is mol%, and the scintillator crystal has a light output intensity of less than 0.3% mol% relative to the light output intensity measured during X-ray irradiation, 100 ms after exposure to the X-ray irradiation.

14. The scintillator crystal of claim 11, wherein the scintillator crystal comprises less than 1 × 10⁻⁶ -3 The chromium content is mol%, and the scintillator crystal has a light output intensity of less than 0.2% at 500 ms after exposure to the X-rays, relative to the light output intensity measured during X-ray irradiation.

15. A radiation detection device, the radiation detection device comprising: case; and The scintillator crystal according to claim 1 is located within the housing.

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