Radiation detection device and associated method

Abstract

Method for detecting high-energy radiation in a harsh environment, wherein the method comprises: Exposure of a scintillator single crystal to high-energy radiation at a temperature of more than approximately 175°C; and Detecting the high-energy radiation with an avalanche photodiode coupled to the scintillator, wherein the scintillator single crystal has a praseodymium-doped composition; characterized by the fact that the scintillator single crystal (La x Y 1-x ) 2Si2O7: Pr is, where (0, 2

Description

BACKGROUND

[0001] This invention relates generally to scintillator single crystals and in particular to a scintillator single crystal that functions at a high temperature and detects high-energy radiation.

[0002] There is currently a need for gamma-ray detection in the oil drilling industry. Gross gamma-ray counting is typically used for log-depth matching and as a shale / sand contrast indicator. Gamma-ray detectors can also be used to derive lithology, porosity, and permeability, which indicate the location, volume, and ease of oil production. A small, robust sensor capable of detecting such radiation is highly desirable and necessary for the harsh wellbore environments where vibration levels exceed 20 times the RMS acceleration (Grms) and temperatures can vary widely from below room temperature to over 175°C.

[0003] Several current technologies use gamma sensors containing photomultiplier tubes (PMTs) spectrally tuned to scintillators. The scintillators emit UV or blue light when excited by high-energy radiation, such as gamma rays, and the PMTs convert these UV or blue light signals into readable electronic signals. However, the lifetime of PMTs decreases considerably at high temperatures. This can result in unacceptably short lifetimes, significantly increasing their cost. Furthermore, PMTs often require high operating voltages and are fragile and susceptible to interference when vibration levels are high. Under these conditions, the use of solid-state avalanche photodiodes (APDs) instead of PMTs for high-energy radiation detection is desirable.

[0004] Solid-state avalanche photodiodes (APDs) can have a different spectral profile than PMTs, and the scintillators used with semiconductor APDs should ideally be spectrally matched to the APDs. The gamma-ray peak resolution of the currently used scintillator, made from tellurium-activated alkali halide crystals, decreases significantly at temperatures above 175°C. Previously, lutetium and yttrium orthosilicates were used as scintillator materials. However, it has been found that these orthosilicates do not have high-temperature stable emission properties. A praseodymium-doped lutetium pyrosilicate scintillator has been investigated for use in positron emission tomography (PET).However, it is known that lutetium, lanthanum, gadolinium and rubidium have an inherent gamma ray emission and are therefore not the best to be used for the detection of high-energy radiation, including gamma radiation.

[0005] US 7,939,808 B1 describes a method and apparatus for detecting high-energy radiation in a harsh environment, comprising the features of the preambles of independent claims 1 and 8. Exemplary scintillator compositions include CS2LiLaBr6, CS2LiLaCl6, CS2LiLaI6, and CS2LiLuI6.

[0006] US 2005 / 0285041A1 describes a similar method and device for detecting high-energy radiation, using as examples of scintillator materials cerium-activated CsSrCl3 (CsSr 0,98 Ce 0,02 Cl3) and Cerium-activated and charge-compensated CsCaCl3 (CsCa 0,96 Ce 0,02 N / a 0,02 Cl3) was used.

[0007] AU 1978034461 A1 describes an X-ray detector comprising an X-ray detection element and a detection device that responds to the fluorescence radiation generated by the X-ray detection element, wherein the X-ray detection element contains a fluorescent material that emits a short afterglow and exhibits high sensitivity to the X-ray radiation to be detected. The fluorescent material for the X-ray detection element may be a cerium- or europium-activated fluorescent material, in particular one of the phosphors Y₂SiO₅:Ce, Y₂Si₂O₇:Ce, or Y₃Al₅O₇. 12 :Ce included.

[0008] Consequently, there is a continuing need for a device and methods that function at a wide range of temperature levels, including temperatures as high as or above 175°C, for the detection of high-energy radiation without significant impairment of the detected signals. SHORT DESCRIPTION

[0009] Embodiments of the invention are directed to a device comprising a scintillator single crystal and its mode of operation.

[0010] In one embodiment, a method for detecting high-energy radiation in a harsh environment is disclosed. The method includes subjecting a scintillator single crystal to the high-energy radiation at a temperature greater than approximately 175°C and detecting the high-energy radiation with an avalanche photodiode coupled to the scintillator. The scintillator single crystal contains a praseodymium-doped composition consisting of (La x Y 1-x )2Si2O7: Pr, ABCl 3-y X y :Pr, A2(Li, Na)LaCl 6-y X y:Pr or any combination thereof is selected. As used herein, A is cesium, rubidium, potassium, sodium, or a combination thereof, while B is calcium, barium, strontium, magnesium, cadmium, zinc, or a combination thereof, and X is bromine, iodine, or a combination thereof. Furthermore, (0 <x<1) und (0≤y<3). Gemäß der Erfindung ist der Szintillator-Einkristall (La x Y 1-x ) 2Si2O7: Pr, where (0,2 <x<0,8).

[0011] In one embodiment, a device for detecting high-energy radiation in a harsh environment is disclosed. The device comprises a single-crystal scintillator and an avalanche photodiode coupled to the single-crystal scintillator. The single-crystal scintillator is exposed to a temperature greater than approximately 175°C and to a vibration level greater than approximately 20 Grms. The single-crystal scintillator contains a praseodymium-doped composition consisting of (La x Y1-x )2Si2O7: Pr, ABCl 3-y X y :Pr, A2(Li, Na) LaCl 6-y X y : Pr or any combination thereof is selected. As used herein, A is cesium, rubidium, potassium, sodium, or a combination thereof, while B is calcium, barium, strontium, magnesium, cadmium, zinc, or a combination thereof, and X is bromine, iodine, or a combination thereof. Furthermore, (0 <x<1) und (0≤y<3). Gemäß der Erfindung ist der Szintillator-Einkristall (La x Y 1-x ) 2Si2O7: Pr, where (0,2 <x<0,8) DRAWINGS

[0012] These and other advantages and features will be more easily understood with reference to the following detailed description of preferred embodiments of the invention, which is presented in conjunction with the accompanying drawings. Fig. Figure 1 shows a perspective view of a device containing the solid-state photomultiplier device according to an embodiment of the present invention; Fig. Figure 2 shows an emission wavelength spectrum of a lanthanum pyrosilicate (La2Si2O7) composition with praseodymium doping at excitation with 235 nm according to an embodiment of the present invention. Fig. Figure 3 shows a graphical representation of the temperature dependence of the luminescence intensity of a lanthanum pyrosilicate (La2Si2O7) composition with praseodymium doping according to an embodiment of the present invention; Fig. Figure 4 shows a graphical representation of the temperature dependence of the luminescence intensity with regard to a Cs2LiLaCl6:Pr composition according to an embodiment that does not belong to the claimed invention; Fig. Figure 5 shows an emission wavelength spectrum of a Cs2NaLaCl6:Pr composition with praseodymium doping at excitation with 235 nm according to an embodiment that does not belong to the claimed invention. Fig. Figure 6 shows a graphical representation of the temperature dependence of the luminescence intensity of Cs2NaLaCl6:Pr according to an embodiment that does not belong to the claimed invention; Fig. Figure 7 shows a graphical representation of the temperature dependence of the luminescence intensity of Cs2NaYCl6:Pr according to an embodiment that does not belong to the claimed invention. DETAILED DESCRIPTION

[0013] Aspects of the present invention are described below in greater detail with reference to exemplary embodiments as illustrated in the accompanying drawings. While the present invention is described below with reference to preferred embodiments, it should be understood that the present invention is not limited thereto. Those skilled in the art who have access to the teachings presented herein will recognize further implementations, modifications, and embodiments, as well as further areas of application, which are within the scope of protection of the present invention as disclosed and claimed herein and in respect of which the present invention could be of considerable benefit.

[0014] In the following description, whenever it is stated that a particular aspect or feature of an embodiment of the invention comprises or consists of at least one element from a group and combinations thereof, it is understood that the aspect or feature may comprise or consist of any one of the elements of the group, either individually or in combination with any one of the other elements from that group.

[0015] In the following description and the claims that follow, the singular forms “ein”, “eine” and “der”, “die” or “das” also include multiple references, unless the context clearly indicates otherwise.

[0016] Approximation expressions, such as those used throughout this description and the claims, may be used to modify any quantitative representation that could permissibly vary without altering the underlying function with which it relates. Accordingly, a value modified by an expression or expressions such as "approximately" or "essentially" may not be restricted to the exact stated value and may include values ​​that differ from the stated value. In at least some cases, the approximation expression may correspond to the accuracy of an instrument used to measure the value.

[0017] One aspect of the present invention relates to a single-crystal scintillator for use in oil drilling applications in harsh borehole environments where vibration levels are in the range of about 20-30 Grms. Furthermore, the single-crystal scintillator described herein is functional at high temperatures and over a wide temperature range and is not very sensitive to temperature fluctuations.

[0018] Scintillator materials are commonly used as a component of radiation detectors for gamma rays, X-rays, cosmic rays, and particles with energy levels above approximately 1 keV. A scintillator crystal is coupled to a light-detecting device, i.e., a photodetector. When photons from a radionuclide source strike the crystal, the crystal emits light. The photodetector generates an electrical signal proportional to the number of received light pulses and their intensity.

[0019] In an exemplary embodiment, which is described in Fig. As disclosed in Figure 1, a system 10 includes a scintillator 12. A scintillator material can absorb radiation energy by exciting electrons and holes. These electrons and holes can recombine and emit photons. In the present embodiment, the scintillator 12 is capable of converting high-energy radiation 14 into photons 16. A photodetector device 20 can include one or more avalanche photodiodes to detect the photons 16 and convert them into electrical or electronic signals (not illustrated) that can be detected by associated electronics to determine the time, energy, and position of the incident high-energy radiation. In one embodiment, the system 10 is a device for detecting high-energy radiation.

[0020] In general, desirable properties of a scintillator material include high density (for high radiation stopping power), high light yield, fast decay time, high energy resolution, good environmental stability, and the availability of large single crystals. These properties are related to the material's fundamental properties, namely the band gap (important for light yield), the carrier transport efficiency (relevant for the decay of the scintillation), and the optical, chemical, and structural properties.

[0021] "Attenuation" is the ability of a material to absorb radiation and is directly related to the density and Z (atomic number) of the scintillator material. Scintillator materials with high attenuation allow little or no radiation to pass through, and this is a significant advantage in radiation capture efficiency.

[0022] In the sense used here, the term "light yield" is the amount of visible light emitted by the scintillator after it has been excited by a pulse of X-ray or gamma radiation. High light yield is desirable because it improves the radiation detector's ability to convert the light into an electrical pulse.

[0023] The term "decay time" refers to the time required for the intensity of the light emitted by the scintillator to decrease to a specified fraction of the light intensity at the moment the radiation excitation ceases. For many applications, such as PET scanners, shorter decay times are desirable because they enable efficient coincidence counting of gamma rays. Consequently, scan times are reduced, and images can be improved by eliminating random counts due to unintended coincidences.

[0024] The "energy resolution" of a radiation detector refers to its ability to distinguish between energy beams (e.g., gamma rays) that have very similar energy levels. Energy resolution is usually reported as a process value after measurements have been taken at a standard radiation emission energy for a given energy source. Lower energy resolution values ​​are highly desirable because they generally result in a higher-quality radiation detector.

[0025] Scintillator materials can be prepared and used in various forms. For example, in some embodiments, the scintillator material is in a monocrystalline form (single crystal form). In its single-crystal form, scintillator 12 exhibits a greater tendency toward transparency and is particularly useful for detectors of high-energy radiation, such as those used for the detection of gamma rays. Therefore, in one embodiment of the invention, the scintillator material used herein is in its single-crystal form.

[0026] The disclosed scintillator 12 according to this description is configured to detect radiation while operating over a wide temperature range without any significant loss of radiation detection capability. The scintillator 12 disclosed herein is capable of functioning in a temperature range from below room temperature to elevated temperatures, such as -50°C to 225°C. In one embodiment, the scintillator is configured to function in a temperature range from -40°C to 200°C.

[0027] In one embodiment, the scintillator 12 is configured to operate at elevated temperatures, such as temperatures above 175°C. In the sense used herein, "configured to operate at temperatures above 175°C" means that the scintillator is capable of operating at temperatures above 175°C without losing its ability to operate at temperatures below 175°C. In another embodiment, the scintillator 12 is configured to operate at temperatures even above 200°C. In yet another embodiment, the scintillator 12 can operate at temperatures below room temperature. In one embodiment, the scintillator 12 can be configured to operate at temperatures below approximately -40°C.

[0028] In one embodiment, the disclosed scintillator 12 is configured to detect incident radiation while operating over a wide temperature range above 200°C without significant loss of radiation detection capability. In the sense used herein, "detects radiation while operating over a wide temperature range above 200°C" means that a single arrangement of the scintillator 12 is capable of operating within this temperature range without any substantial modification of the composition or arrangement of the scintillator 12 for operation in any sub-range of this temperature range. For example, the scintillator 12, in its single configuration, may be capable of operation from -25°C to 175°C without the need to exchange or correct the composition of the scintillator, or without the need for any additional protection of the scintillator.In another exemplary embodiment, the scintillator in its one configuration with a specific composition is able to operate in the range from 0°C to 200°C without the need to change the configuration or composition of the scintillator, and without the need for additional protection for the scintillator.

[0029] In the sense used herein, the terms “capable of operating” or “configured” for operation under a temperature range mean that there is no significant variation in the peak luminous efficacy of the scintillator 12 within any temperature window of the disclosed temperature range. In the sense used herein, the “luminous efficacy of the scintillator” is the total number of photons emitted upon interaction with ionizing radiation. Normally, the luminous efficacy of the scintillator is measured as the number of photons / MeV.

[0030] The scintillator 12 disclosed herein can be configured to operate with a high luminous efficacy in the specified temperature ranges compared to existing scintillator materials. The peak luminous efficacy of many currently used scintillator materials is expected to decrease significantly at high temperatures, such as those above 175°C. A drop in luminous efficacy of more than 80% is typically observed in many commonly used scintillator materials. The variation in luminous efficacy at high temperatures can be measured using the relative photoluminescence intensity at that temperature with respect to room temperature.

[0031] The scintillator materials used herein in the various embodiments exhibit a considerably high light yield even at high temperatures. In one embodiment, the photoluminescence intensity (alternatively, luminescence intensity) of the single-crystal scintillator, as described herein, is greater than approximately 60% of the luminescence intensity of this single crystal at room temperature at temperatures above 200°C. That is, the decrease in luminescence intensity from room temperature to a temperature above 200°C is less than approximately 40%. In another, specific embodiment, the scintillator single crystal exhibits a luminescence intensity at temperatures above 200°C that is greater than approximately 75% of the luminescence intensity of the same single crystal at room temperature.

[0032] Some embodiments of the invention are directed here to a scintillator material comprising a praseodymium-doped composition, which (La xY 1-x )2Si2O7:Pr has, where 0.2 < x < 0.8..

[0033] The amount of activator present in a scintillator composition depends on various factors, such as the support material used, the lattice site where the activator is substituted, the desired emission properties and decay time, and the type of detection device into which the scintillator is incorporated. In some embodiments of this invention, trivalent praseodymium is used as an activator.

[0034] Praseodymium is used as the dopant in the scintillator compositions in various embodiments described herein. The amount of praseodymium present in the scintillator single crystal can range from about 0.5 atomic% to about 10 atomic%. In one embodiment, the degree of praseodymium doping in the scintillator single crystal ranges from about 0.5 atomic% to about 2 atomic%.

[0035] Furthermore, it is desirable that the scintillator material used herein has an emission wavelength in the range of approximately 200 nm to approximately 400 nm in order to match the spectral wavelength of the APD that is best suited for use with this scintillator for radiation detection. In one embodiment, the scintillator material used herein has an emission wavelength greater than approximately 200 nm and less than approximately 400 nm. In another embodiment, the scintillator material has an emission wavelength in the range of approximately 275 nm to approximately 350 nm.

[0036] According to the invention, a lanthanum pyrosilicate (La₂Si₂O₇) doped with praseodymium is used as the scintillator material for the high-energy radiation. In the sense used herein, praseodymium occupies a lanthanum site after doping. This composition with 2% praseodymium doping appears to exhibit an emission wavelength in the range of about 250 nm to about 325 nm when excited with a wavelength of 235 nm, as shown in Fig. Figure 2 illustrates that it has good temperature stability of the photoluminescence intensity, as shown in Fig. Figure 3 illustrates this when investigated using powder samples of this composition. In one embodiment, the scintillator material comprises a rare-earth-metal-substituted lanthanum pyrosilicate composition doped with praseodymium. In one embodiment, the scintillator material comprises a yttrium-substituted lanthanum pyrosilicate composition doped with praseodymium [(Lax Y 1-x ) 2Si2O7: Pr], 0 <x<1 (alternativ [(La x (Y+Pr) 1-x )2Si2O7]), 0 <x<1. Es sind verschiedene Zusammensetzungen in diesem Zusammensetzungsbereich als Szintillator-Einkristall für die Detektion energiereicher Strahlung verwendbar, da festgestellt wurde, dass sie Photonen in dem erforderlichen Wellenlängenbereich von etwa 250 nm bis etwa 375 nm für die Detektion energiereicher Strahlung emittieren. Gemäß der Erfindung wird ein Einkristall aus (La x Y 1-x )2Si2O7:Pr as a scintillator with a variation in composition of 0.2 <x<0,8 verwendet. In einer speziellen Ausführungsform wird ein Einkristall aus (La 0,6 Y 0,4 )2Si2O7 with 2% praseodymium doping on a lanthanum (or yttrium) site and used as a scintillator 12 for the detection of gamma rays in a borehole application.

[0037] In an embodiment not belonging to the claimed invention, the scintillator is a perovskite halide with the composition ABCl 3-y X y with a praseodymion as the activator substituting one B-site. In the sense used herein, A is cesium, rubidium, potassium, sodium, silver, or any combination of any of these. B is calcium, barium, strontium, magnesium, cadmium, zinc, or any combination of these. x can be bromine, iodine, or a combination of bromine and iodine. y can be 0 or can vary between 0 and 3, excluding the endpoints.

[0038] Accordingly, in an embodiment not belonging to the claimed invention, the scintillator single crystal used herein is CsCaCl3:Pr. In another embodiment not belonging to the claimed invention, the scintillator composition is a partially barium-substituted cesium-calcium limestone with a praseodymium doping at a calcium site having the composition CsCaCl3:Pr. 3-y Br y :Pr, and (0 <y≤1).

[0039] As mentioned above, when the activator is incorporated into the ABX3 perovskite lattice, it occupies the position of the divalent species B in the lattice. Charge compensation occurs through the creation of defects and vacancies. This could lead to a reduction in the luminescence intensity of the composition. Along with the activator, a charge compensator is incorporated into the lattice to help increase efficiency by preventing the creation of defects and vacancies. For a halide perovskite with a trivalent praseodymion as the activator, the charge compensator used is at least one of monovalent sodium or lithium ions.

[0040] In a further embodiment of the scintillator composition not belonging to the claimed invention, the matrix material used herein is in the form of a solid solution of at least two halide perovskites. For the purposes of this invention, the term "solid solution" means a mixture of the halide perovskites in solid, crystalline form, which may contain a single phase or multiple phases. For example, the perovskite halide may contain an element A as a combination of any two, three, or four elements from the group consisting of cesium, rubidium, potassium, and sodium. In another example, the solid solution is based on a mixture of a first halide perovskite and a second halide perovskite in any desired ratio.

[0041] In an embodiment not belonging to the claimed invention, the scintillator is an elpasolite with a praseodymion activator. Elpasolites are particularly suitable for scintillator applications because it is straightforward to grow single crystals from elpasolites from the melt. In one embodiment, the scintillator single crystal has the composition A2(Li, Na)LaCl₂. 6-y X y Pr, where A is cesium, rubidium, potassium, sodium, silver, or any combination thereof. X can be bromine, iodine, or a combination of bromine and iodine. 'y' can be 0 or can vary between 0 and 3, excluding the endpoints. The praseodymium can be doped at the lanthanum site in this composition.

[0042] One elpasolite composition commonly used in scintillator formulations is cerium-activated Cs₂LiYCl₆ (CLYC). This composition appears to exhibit good high-temperature stability of its emission properties. It is also a Cs₂LiYCl₆ composition. e The composition Cs₂LiLaCl₆:Pr is known, but the useful scintillator properties of this composition need to be investigated. It has been found that a small substitution of barium at the chlorine site of CLYC impairs the high-temperature stability of the emission of these compositions. In another embodiment, a scintillator single crystal with the composition Cs₂LiLaCl₆:Pr is used in a radiation detector device. It has been found that the emission efficiency of this composition (in a study with powder samples) drops by more than 75% at a temperature above approximately 200°C, as shown in Fig. 4 illustrates.

[0043] In an embodiment not belonging to the claimed invention, a scintillator single crystal with the composition Cs2NaLaCl is used. 6-y Br y :Pr, (0≤y≤1), with praseodymium doping at the lanthanum site. In a special embodiment not belonging to the claimed invention, a composition of Cs2NaLaCl6:Pr is used, and it has been found that this exhibits spectral similarity to a SiC-APD. Fig. Figure 5 shows an emission wavelength in the range of approximately 250 nm to approximately 325 nm when excited with a wavelength of 235 nm. High temperature stability of the luminescence intensity of this composition can be demonstrated, as in Fig. 6 can be seen when this is investigated using powder samples. In another special embodiment not belonging to the claimed invention, a composition of Cs2NaYCl6:Pr is used, and it has been found that this exhibits spectral similarity to a SiC APD and also high temperature stability of the emission efficiency, as in Fig. Figure 7 illustrates an investigation using powder samples.

[0044] In a special embodiment not belonging to the claimed invention, a scintillator single crystal with the composition Cs2(Li,Na)LaCl is used. 6-y Br y Pr and (0≤y≤1) are used. It has been found that a composition of Cs2Li 0,5 La 0,5Cl6Br:Pr, used in single-crystal form as a scintillator in a high-energy detection device, exhibits spectral similarity to a SiC APD and also high temperature stability of the luminescence intensity. Only a 20% reduction in luminescence intensity was observed for this scintillator at an operating temperature of approximately 200°C.

[0045] One aspect of the invention discloses a method for detecting high-energy radiation over a wide temperature range using a scintillator. The temperature range in which the scintillator operates can be 200°C or higher. The scintillator can be operated in harsh environments with high temperatures and high vibrations.

[0046] One objective of a scintillator according to one embodiment of the present invention is the detection of high-energy radiation, such as gamma rays, neutrons, or X-rays. The scintillator according to one embodiment of the present invention can be used particularly in harsh environments (e.g., those exhibiting high vibration, high temperature, etc.) that require robust materials. In one embodiment, the scintillator single crystal is exposed to the high-energy radiation at a vibration level in the range of approximately 20 to 30 Grms. In a particular embodiment, the scintillator single crystal is exposed to the high-energy radiation at a vibration level of approximately 35 Grms.

[0047] Accordingly, a method for detecting high-energy radiation in a borehole or wireline application with a harsh environment involves bombarding a scintillator with the high-energy radiation, generating photons, and detecting these photons using an avalanche photodiode at a temperature above approximately 175°C. Linear-mode APDs can be used for some oil well applications. However, linear-mode APDs can be temperature-sensitive, reducing the detector's sensitivity and energy resolution.

[0048] In one embodiment, a charge carrier generated by the detected photons is accelerated to a sufficiently high kinetic energy by an applied high electric field. It generates secondary charge pairs through impact ionization, resulting in high gain. In a Geiger mode, the APD is operated beyond its breakdown voltage, leading to further impact ionization and high gain. A single APD may be limited in terms of detection range, light capture, and radiation event detection. In some borehole applications, differentiation between low and high photon fluxes is desirable. An array of APDs is capable of detecting multiple photons and can be scaled to a larger detection range; however, APD arrays fabricated with a silicon semiconductor may lose sensitivity at increasing temperatures.

[0049] In one embodiment, the device 20 ( Fig. 1) Used in a solid-state photomultiplier (SSPM) device containing a single-pixel (microcell) array of an avalanche photodiode (APD) operating in Geiger mode. In this configuration, the array is biased above the breakdown voltage, and a single absorbed and detected photon can trigger an avalanche breakdown. An avalanche breakdown causes the charge stored in each APD to discharge in a rapid current pulse. An erase device used in conjunction with an APD can limit the charging current.

[0050] In one embodiment, the system 10 can contain a large number of solid-state photomultiplier devices 20, which are arranged adjacent to one another in a tile-like pattern and cover a comparatively large area. In one embodiment, the arrays of solid-state photomultiplier devices are arranged adjacent to one another in the system 10 in a tile-like pattern to cover an area of ​​5 mm. 2 or to cover more.

[0051] The detected photons are further processed using associated electronics that operate at a temperature of more than approximately 175°C in order to be converted into electrical signals.

[0052] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to include any number of alterations, modifications, substitutions, or equivalent arrangements not described above, but which are consistent with the scope and extent of the invention. Furthermore, it should be understood that, although various embodiments of the invention have been described, aspects of the invention may only include some of the described embodiments. Accordingly, the invention is not to be considered as limited by the foregoing description, but only by the scope of protection of the appended claims.

Claims

[1] Method for detecting high-energy radiation in a harsh environment, wherein the method comprises: Exposure of a scintillator single crystal to high-energy radiation at a temperature of more than approximately 175°C; and Detecting the high-energy radiation with an avalanche photodiode coupled to the scintillator, wherein the scintillator single crystal has a praseodymium-doped composition; characterized by the fact that the scintillator single crystal (La x Y 1-x ) 2Si2O7: Pr is, where (0, 2 <x<0, 8) . [2] Method according to claim 1, wherein the luminescence intensity of the scintillator single crystal at a temperature above 200°C is greater than about 60% of the luminescence intensity of the scintillator single crystal at room temperature. [3] Method according to claim 1, wherein the luminescence intensity of the scintillator single crystal at a temperature above 200°C is greater than about 75% of the luminescence intensity of the scintillator single crystal at room temperature. [4] Method according to claim 1, wherein the scintillator single crystal generates photons in an emission wavelength range of about 275 nm to about 350 nm. [5] Method according to claim 1, wherein the amount of praseodymium present in the scintillator single crystal composition is in the range of about 0.5 mol% to about 10 mol%. [6] Method according to claim 1, wherein the scintillator single crystal is exposed to high-energy radiation at a vibration level of more than about 20 Grms. [7] Method according to claim 1, wherein the high-energy radiation is gamma radiation. [8] Device for detecting high-energy radiation in a harsh environment, the device comprising: a scintillator single crystal; and an avalanche photodiode coupled to the scintillator single crystal, wherein the scintillator single crystal is subjected to a temperature of more than about 175°C and a vibration level in the range of about 20 Grms to 30 Grms and has a praseodymium-doped composition, characterized by the fact that the scintillator single crystal (La x Y 1-x ) 2Si2O7: Pr is, where (0, 2 <x<0, 8) .[9] Device according to claim 8, wherein the luminescence intensity of the single crystal at a temperature above 200°C is greater than about 60% of the luminescence intensity of the single crystal at room temperature. [10] Device according to claim 8, wherein the luminescence intensity of the single crystal at a temperature above 200°C is greater than about 75% of the luminescence intensity of the single crystal at room temperature. [11] Device according to claim 8, wherein the scintillator single crystal has an emission wavelength of more than about 200 nm. [12] Device according to claim 11, wherein the scintillator single crystal has an emission wavelength in a range of about 275 nm to about 350 nm. [13] Device according to claim 8, wherein the amount of praseodymium present in the scintillator single crystal is in the range of about 0.5 atomic % to about 3 atomic %.

Images