Direct type X-ray detector, preparation method thereof and application of direct type X-ray detector in X-ray detection in extreme environment

Abstract

The invention discloses a direct X-ray detector, a preparation method thereof and application of the direct X-ray detector in X-ray detection in an extreme environment, and belongs to the technical field of X-ray detection. The direct X-ray detector comprises a sesquioxide, a positive electrode layer and a negative electrode layer, and the sesquioxide is arranged between the positive electrode layer and the negative electrode layer; the sesquioxide comprises any one of sesquioxide crystals, sesquioxide ceramics and sesquioxide glass. The sesquioxide crystal prepared by the invention has stable physical and chemical properties, excellent mechanical properties, excellent X-ray detection performance and extreme environment resistance, and a direct X-ray detector is prepared after a positive electrode layer and a negative electrode layer are sputtered on the top surface and the bottom surface respectively. The detector can tolerate extreme conditions such as extremely high detection temperature, high humidity, strong corrosion and the like, has excellent performance of high sensitivity and low detection limit, improves the accuracy of X-ray detection in an extreme environment, and meets the requirements of scientific and technological development.

Description

Technical Field

[0001] The present invention belongs to the technical field of X-ray detection, and particularly relates to a direct X-ray detector, a preparation method thereof, and an application in X-ray detection in extreme environments. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and it is not necessarily regarded as an admission or an indication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] According to different working principles of X-ray detectors, they can be divided into direct X-ray detectors and indirect X-ray detectors. The former is mainly a semiconductor detector, and the latter is mainly a scintillator detector. A direct X-ray detector is a detector that directly converts X-rays into electrical signals. Due to its characteristics of simple device structure, fast response speed, and high spatial resolution, it has a wide range of applications in industrial inspection, medical imaging, computed tomography, and other fields.

[0004] Extreme environment service refers to the process in which materials, devices, and equipment serve in extreme environments such as nuclear reactors, deep space, and deep sea. Due to the characteristics of these extreme environments, such as ultra-high temperature, strong radiation, high humidity, high pressure, and strong corrosion, more stringent requirements are put forward for the performance of X-ray detection materials, such as the temperature tolerance, radiation resistance, physical and chemical stability, etc. For nuclear reactors, the internal environment has ultra-high temperatures above 1000 °C and high-pressure strong radiation, which requires that the X-ray detection materials have a high melting point, good high-pressure stability, and radiation resistance, and can adapt to the service environment of high temperature, high pressure, and strong radiation, and maintain stable performance and long-term operation. For deep space exploration, the extreme environment of space radiation and alternating high and low temperatures also requires that the X-ray detection materials have good radiation resistance and physical and chemical stability. For the deep sea exploration field, while facing huge water pressure and low temperature environments, it also has the characteristics of high humidity and strong corrosion, which puts forward higher requirements for the anti-deliquescence and anti-corrosion properties of X-ray detection materials.

[0005] In currently common semiconductor X-ray detectors, amorphous Se is prone to crystallization at 40-60 °C, the bandgap of Si is small and it can only be used under liquid nitrogen, and the X-ray absorption coefficients of detectors based on these two materials are small, and the absorption ability for high-energy X-rays is weak. Moreover, the preparation of high-quality Cd(Zn)Te is difficult and the cost is high. Although X-ray detectors based on metal perovskite materials have excellent X-ray absorption characteristics, large ion migration rate-life product, etc., they have serious problems of ion migration and easy deliquescence. These materials are difficult to meet the detection requirements under extreme service environments of ultra-high temperature, strong radiation, and high humidity. Therefore, it is of great significance to develop an X-ray detection material with strong X-ray absorption ability, excellent performance, and capable of being used in extreme environments.

[0006] Sesquioxides have an ultra-high melting point of about 2450 °C and stable physical and chemical properties, and can withstand extremely high detection temperatures and extreme conditions such as high humidity and strong corrosion. Taking lutetium oxide (Lu 2 O 3 ) as an example, it has an extremely high density (9.42 g / cm 3 ), and has a strong stopping ability for various rays. When X-rays pass through the material, it will greatly increase the probability of interaction between photons and electrons, thereby enhancing the absorption of X-rays. Therefore, sesquioxides are an ideal material in the field of X-ray detection under extreme service environments.

[0007] However, at present, sesquioxide materials doped with rare earth elements are mainly used as scintillators for indirect detection of X-rays. In this process, the absorbed X-ray photons are first converted into visible light photons by the scintillator, and then the visible light photons are converted into electrical signals by devices such as photodiodes, thereby realizing the indirect detection of X-rays. For example, Tao Min (Tao Min. Research on rare earth doped Lu 2 O 3 / CdS composite film X-ray detector [D]. Hubei University, 2020.) studied a rare earth doped Lu 2 O 3 / CdS composite film X-ray detector. Due to the conversion process from X-rays to visible light and then to electrical signals, each step will cause a certain amount of energy loss; moreover, affected by the luminescence decay time of the scintillator and the scattering of visible light, the response speed and spatial resolution of indirect X-ray detection are also relatively poor, which limits the application of indirect X-ray detectors.

[0008] Therefore, there is an urgent need to develop a direct X-ray detector based on sesquioxides to improve the detection accuracy and meet the requirements of use in extreme environments. Summary of the Invention

[0009] To solve the deficiencies of the prior art, the object of the present invention is to provide a direct X-ray detector, a preparation method thereof, and an application in X-ray detection in extreme environments. The direct X-ray detector provided by the present invention directly converts X-rays into electrical signals to reduce energy loss and improve the energy resolution, spatial resolution, and response speed of X-ray detection. The direct X-ray detector based on sesquioxide provided by the present invention has advantages such as high sensitivity and low detection limit, and solves the problems of energy conversion loss, slow response speed, and limited spatial resolution existing in sesquioxide scintillation materials when detecting X-rays.

[0010] To achieve the above object, the technical solution of the present invention is as follows:

[0011] In the first aspect of the present invention, a direct X-ray detector is provided, which includes sesquioxide, a positive electrode layer, and a negative electrode layer, and the sesquioxide crystal is disposed between the positive electrode layer and the negative electrode layer;

[0012] The sesquioxide includes any one of sesquioxide crystals, sesquioxide ceramics, and sesquioxide glasses.

[0013] Sesquioxide crystals, sesquioxide ceramics, and sesquioxide glasses are important inorganic non-metallic materials. The preparation process is simple and it is easy to achieve uniform rare earth ion doping. In particular, sesquioxide ceramics and sesquioxide glasses are easy to achieve high-concentration rare earth ion doping. All three have unique structures and excellent physical and chemical properties, and have important application values in the fields of optics, electricity, etc., and are ideal X-ray detection materials.

[0014] The direct X-ray detector provided by the present invention fills the gap in the field of direct X-ray detection in extreme environments such as ultra-high temperature and strong radiation. At the same time, through this detector, X-rays are directly converted into electrical signals to reduce energy loss, so as to improve the energy resolution, spatial resolution, and response speed of X-ray detection.

[0015] In some embodiments of the present invention, the thickness of the sesquioxide is 0.5 - 1.5 mm, preferably 0.8 - 1.2 mm, and specifically can be 0.8 mm, 0.9 mm, 1.0 mm, etc.

[0016] In some embodiments of the present invention, the sesquioxide is preferably a sesquioxide crystal.

[0017] Preferably, the chemical formula of the sesquioxide crystal is (Re a Sc b Y c Lu d ) 2 O 3, where a + b + c + d = 1, and 0 ≤ a ≤ 0.1, 0 ≤ b, c, d ≤ 1, and Re is selected from any one of ytterbium, erbium, holmium, thulium, europium, dysprosium, samarium, and neodymium.

[0018] Since the density of lutetium oxide is higher than that of scandium oxide and yttrium oxide, the sesquioxide crystal is preferably a lutetium oxide-based crystal, and the chemical formula of the sesquioxide crystal is preferably (Re a Lu 1-a ) 2 O 3 , where 0 ≤ a ≤ 0.1, and Re is selected from any one of ytterbium, erbium, holmium, thulium, europium, dysprosium, samarium, and neodymium.

[0019] Preferably, the sesquioxide crystal is a lutetium oxide single crystal.

[0020] Preferably, the lutetium oxide single crystal is a single crystal in the (111) direction, belonging to the cubic crystal system, and the space group is Ia - 3, α = 90°, β = 90°, γ = 90°.

[0021] Preferably, the positive electrode layer is disposed on the upper surface of the lutetium oxide single crystal in the (111) direction, and the negative electrode layer is disposed on the lower surface of the lutetium oxide single crystal in the (111) direction.

[0022] In some embodiments of the present invention, the materials of the positive electrode layer and the negative electrode layer are each selected from any one of gold, platinum, molybdenum, and tungsten.

[0023] Preferably, the material of the positive electrode layer is gold, and the thickness of the positive electrode layer is 50 - 150 nm, preferably 80 - 120 nm.

[0024] Preferably, the material of the negative electrode layer is gold, and the thickness of the negative electrode layer is 50 - 150 nm, preferably 80 - 120 nm.

[0025] In a second aspect of the present invention, there is provided a method for preparing the above-mentioned direct X-ray detector for use in extreme environments, comprising:

[0026] Depositing a positive electrode layer and a negative electrode layer on the surface of the sesquioxide by ion sputtering to obtain a direct X-ray detector.

[0027] In some embodiments of the present invention, the sesquioxide is a sesquioxide crystal, and its chemical formula is (Re a Sc b Y c Lu d ) 2 O 3, where a + b + c + d = 1, and 0 ≤ a ≤ 0.1, 0 ≤ b, c, d ≤ 1, and Re is selected from any one of ytterbium, erbium, holmium, thulium, europium, dysprosium, samarium, and neodymium.

[0028] Preferably, before preparing the direct X-ray detector, the sesquioxide crystal is oriented on an X-ray orientator, crystal cutting is performed after determining the direction, and finally the cut wafer is polished. The positive electrode layer is sputtered on the top surface of the sesquioxide crystal by an ion sputtering instrument, and the negative electrode layer is sputtered on the top and bottom surfaces of the sesquioxide crystal by an ion sputtering instrument to obtain a direct X-ray detector based on the sesquioxide crystal.

[0029] In some embodiments of the present invention, the preparation method of the sesquioxide crystal includes the following steps:

[0030] The raw materials are pressed into blocks, and crystal growth is carried out by the melt method.

[0031] Preferably, the raw materials are powdery raw materials with a purity of greater than or equal to 99.999%. Using high-purity raw materials is crucial for preparing high-quality crystal materials, which can reduce impurities, improve performance, ensure test reproducibility, avoid side reactions, meet application requirements, and improve growth efficiency.

[0032] In some embodiments of the present invention, the pressing is carried out by isostatic pressing at 150 - 250 MPa for 100 - 150 s. Using isostatic pressing to prepare the material block can make the raw material powder be uniformly pressed in all directions during the pressing process, thereby obtaining a rod with high and uniform density, reducing the density gradient, avoiding defects during crystal growth, and improving the crystal quality; it can effectively eliminate internal defects such as pores and cracks, improve the densification and mechanical strength of the material block, and provide a better basis for subsequent crystal growth.

[0033] To further increase the density of the obtained rod and improve the crystal quality, preferably, the pressing is carried out at 170 - 220 MPa for 100 - 140 s, and more preferably at 190 - 210 MPa for 110 - 130 s.

[0034] In some embodiments of the present invention, the melt method includes any one of the Czochralski method, the edge-defined film-fed growth method, and the temperature gradient method.

[0035] Among them, the Czochralski method includes: the crystal growth atmosphere is a mixed atmosphere of Ar and H 2 The seed crystal is pure R 2 O 3 The seed crystal, the heating method is coil induction heating, the pulling speed is 0.5 - 5 mm / h, and the rotation speed is 10 - 30 rpm; R is selected from any one of Lu, Sc, and Y.

[0036] Preferably, when R is Lu, the seed crystal is a pure lutetium oxide seed crystal in the <111> or <100> direction.

[0037] Among them, the film guiding method includes: the crystal growth atmosphere is a mixed atmosphere of Ar and H 2 , and the seed crystal is pure R 2 O 3 seed crystal, the heating method is induction heating by a coil, the pulling speed is 0.3 - 6 mm / h, and the rotation speed is 8 - 38 rpm; R is selected from any one of Lu, Sc, and Y.

[0038] Preferably, when R is Lu, the seed crystal is a pure lutetium oxide seed crystal in the <111> or <100> direction.

[0039] Among them, the temperature gradient method includes: the crystal growth atmosphere is a mixed atmosphere of Ar and H 2 , no seed crystal is used during crystal growth, or a pure R 2 O 3 seed crystal is placed at the bottom of the crucible, R is selected from any one of Lu, Sc, and Y, or top-seed induced crystallization is used, the heating method is induction heating by a coil, and the temperature is reduced at a rate of 15 - 25 K / h to induce crystal crystallization.

[0040] Preferably, when R is Lu, the pure R 2 O 3 seed crystal is a pure lutetium oxide seed crystal in the <111> or <100> direction.

[0041] Preferably, when using the temperature gradient method for crystal growth, top-rhenium seed induced crystallization is used.

[0042] In a specific embodiment of the present invention, the temperature gradient method includes: placing the charge block in a rhenium crucible, evacuating the furnace chamber to vacuum and then introducing a mixed gas of Ar and H 2 as a protective gas; heating to melt the raw materials, after fully melting, lowering the rhenium seed crystal to 2 mm below the melt surface at a rate of 2 mm / min and then keeping it stationary, and then reducing the temperature at a rate of 20 K / h to induce the melt to crystallize and grow, and slowly cooling after growth to avoid cracking.

[0043] In some embodiments of the present invention, after crystal growth is completed, the crystal is taken out, annealed in an air atmosphere, and then oriented and polished to obtain a sesquioxide crystal. The purpose of the annealing is to release thermal stress and eliminate oxygen vacancies.

[0044] Preferably, the annealing is carried out in a muffle furnace at 1600 - 1700 °C for 48 - 50 h.

[0045] The third aspect of the present invention provides an application of the above-mentioned direct X-ray detector or a direct X-ray detector prepared by the above-mentioned preparation method in X-ray detection in extreme environments.

[0046] Preferably, the extreme environments include nuclear reactors, deep space environments, and deep sea environments.

[0047] The beneficial effects of the present invention are as follows:

[0048] The present invention provides a direct X-ray detector, which is composed of a positive electrode layer, a negative electrode layer, and a sesquioxide disposed between the positive electrode layer and the negative electrode layer. Sesquioxide crystals, sesquioxide ceramics, and sesquioxide glasses all have unique structures and excellent physical and chemical properties, and have important application values in the fields of optics, electricity, etc., and are ideal X-ray detection materials. The sesquioxide crystals prepared by the present invention have stable physical and chemical properties and excellent mechanical properties, have excellent X-ray detection performance and the ability to withstand extreme environments, and a direct X-ray detector is prepared by sputtering a positive electrode layer and a negative electrode layer on the top surface and the bottom surface of the sesquioxide respectively. The prepared direct X-ray detector can withstand extremely high detection temperatures and extreme conditions such as high humidity and strong corrosion, has excellent performance of high sensitivity and low detection limit, improves the accuracy of X-ray detection in extreme environments such as ultra-high temperature and strong radiation, and meets the needs of scientific and technological development.

[0049] The preparation process of the direct X-ray detector provided by the present invention is simple, and the obtained detector has high quality. Among them, the sesquioxide crystals prepared by the melt method have a simple preparation process. The single crystal has high quality, is overall transparent, and there are no visible defects inside the crystal to the naked eye. The electrodes are sputtered on the top surface and the bottom surface of the sesquioxide crystal by ion sputtering, and the preparation is simple and easy to operate, effectively reducing the preparation cost of the device. Description of the Drawings

[0050] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0051] Figure 1 Physical picture of the Lu 2 O 3 single crystal prepared in Example 1 of the present invention;

[0052] Figure 2 Physical picture of the Er:Lu 2 O 3 single crystal prepared in Example 2 of the present invention;

[0053] Figure 3 Physical picture of the Ho:Lu 2 O 3Physical picture of a single crystal;

[0054] Figure 4 Yb:Lu prepared in Example 4 of the present invention 2 O 3 Physical picture of a single crystal;

[0055] Figure 5 Lu prepared in Example 1 of the present invention 2 O 3 Compressive strength test chart of a single crystal;

[0056] Figure 6 Lu prepared in Example 1 of the present invention 2 O 3 Thermal analysis curve of a single crystal;

[0057] Figure 7 Lu prepared in Example 1 of the present invention 2 O 3 XRD chart of a single crystal;

[0058] Figure 8 Based on Lu prepared in Example 1 of the present invention 2 O 3 Schematic diagram of the structure of a direct-type X-ray detector based on a single crystal of Lu

[0059] Figure 9 Based on Lu prepared in Example 1 of the present invention 2 O 3 X-ray absorption coefficient of a direct-type X-ray detector based on a single crystal of Lu

[0060] Figure 10 Based on Lu prepared in Example 1 of the present invention 2 O 3 Carrier mobility-lifetime product of a direct-type X-ray detector based on a single crystal of Lu

[0061] Figure 11 Based on Lu prepared in Example 1 of the present invention 2 O 3 Photocurrent curves of a direct-type X-ray detector based on a single crystal of Lu at different doses;

[0062] Figure 12 Based on Er:Lu prepared in Example 2 of the present invention 2 O 3 Photocurrent curves of a direct-type X-ray detector based on a single crystal of Er:Lu at different doses;

[0063] Figure 13 Based on Ho:Lu prepared in Example 3 of the present invention 2 O 3 Photocurrent curves of a direct-type X-ray detector based on a single crystal of Ho:Lu at different doses;

[0064] Figure 14 For the direct-type X-ray detector based on Yb:Lu single crystal prepared in Example 4 of the present invention 2 O 3 Photocurrent curves at different doses

[0065] Figure 15 For the sensitivity test chart of the direct-type X-ray detector based on Lu single crystal prepared in Example 1 of the present invention 2 O 3

[0066] Figure 16 For the sensitivity test chart of the direct-type X-ray detector based on Er:Lu single crystal prepared in Example 2 of the present invention 2 O 3

[0067] Figure 17 For the sensitivity test chart of the direct-type X-ray detector based on Ho:Lu single crystal prepared in Example 3 of the present invention 2 O 3

[0068] Figure 18 For the sensitivity test chart of the direct-type X-ray detector based on Yb:Lu single crystal prepared in Example 4 of the present invention 2 O 3

[0069] Figure 19 For the detection limit test chart of the direct-type X-ray detector based on Lu single crystal prepared in Example 1 of the present invention 2 O 3

[0070] Figure 20 For the dark current drift curve of the direct-type X-ray detector based on Lu single crystal prepared in Example 1 of the present invention 2 O 3 Detailed implementation manners

[0071] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0072] Example 1 Preparation of a direct-type X-ray detector based on Lu 2 O 3 single crystal

[0073] A direct-type X-ray detector based on Lu 2 O 3 single crystal, including a gold positive electrode layer, a Lu in the (111) direction from top to bottom​​​​​​2 O 3 Single crystal, gold negative electrode layer. The thickness of the gold positive electrode layer is 100 nm. The thickness of the gold negative electrode layer is 100 nm. The positive electrode layer is placed on the upper surface of the (111)-oriented Lu 2 O 3 single crystal, and the negative electrode layer is placed on the lower surface of the (111)-oriented Lu 2 O 3 single crystal. The (111)-oriented Lu 2 O 3 single crystal is a cuboid with a length of 4 mm, a width of 4 mm, and a thickness of 1 mm. The (111)-oriented Lu 2 O 3 single crystal belongs to the cubic crystal system, and the space group is Ia - 3, α = 90°, β = 90°, γ = 90°.

[0074] (1) The (111)-oriented Lu 2 O 3 The preparation method of the single crystal includes the following steps:

[0075] Press the Lu 2 O 3 powder with a purity of 99.999% into a compact by isostatic pressing (pressing the material for 120 s at 200 MPa), and use the temperature gradient method for crystal growth. The specific temperature gradient method includes: placing the pressed compact in a rhenium crucible, evacuating the furnace chamber to vacuum and then introducing a mixed gas of argon and hydrogen as the protective gas. Raise the temperature to the melting point of the raw material to melt it, and keep it at a constant temperature for 4 h to fully melt the raw material. Lower the rhenium seed crystal into the melt surface at a rate of 2 mm / min for 2 mm and then keep it still. Subsequently, lower the temperature at a rate of 20 K / h to induce the melt to crystallize and grow. After the growth is completed, slowly cool down to avoid cracking. Then use a computer numerical control crystal bar processing system to take out the crystal from the crucible. The taken-out crystal is placed in a muffle furnace and annealed at 1650 °C in air for 48 h to release the thermal stress and eliminate the oxygen vacancies, and finally obtain Lu 2 O 3 single crystal. Finally, the obtained Lu 2 O 3 single crystal is subjected to directional cutting and polishing to obtain the (111)-oriented Lu 2 O 3 single crystal, and the physical photo of the crystal is as Figure 1 shown. Test the X-ray diffraction pattern of the directionally polished Lu 2 O 3 crystal, and the result is as Figure 7 shown. Compare it with the PDF standard card to prove that the obtained Lu 2 O3 The single crystal is in the (111) direction.

[0076] (2) Based on Lu 2 O 3 The preparation method of the direct X-ray detector based on the LuO single crystal comprises the following steps:

[0077] Using an ion sputtering instrument, gold is sputtered on the top surface of the LuO single crystal in the (111) direction as the positive electrode, and gold is sputtered on the bottom surface as the negative electrode, with a thickness of 100 nm each, obtaining a direct X-ray detector based on the LuO single crystal, and its structural schematic diagram is as 2 O 3 shown. 2 O 3 shown. Figure 8 shown.

[0078] Test Example 1: Performance test of the direct X-ray detector based on the LuO single crystal 2 O 3 To test the pressure resistance of the direct X-ray detector based on the LuO single crystal prepared in Example 1, the LuO single crystal grown in Example 1 was cut, and a 3 mm × 3 mm × 5 mm bulk was processed for the compressive strength experiment. By applying a certain pressure to the crystal and testing the change of its deformation degree with the pressure, the results are as

[0079] shown. Through calculation, it can be known that its compressive strength reaches 1228.58911 MPa, indicating that the LuO single crystal prepared in Example 1 has excellent mechanical properties and can withstand the extreme environment of higher pressure. 2 O 3 To test the thermal stability of the LuO single crystal prepared in Example 1, the LuO single crystal grown in Example 1 was subjected to thermal analysis test, and the results are as 2 O 3 shown. Through the DSC-TGA curve, it can be seen that in the range from room temperature to 1500 °C, there is no obvious endothermic peak in the DSC curve, and the corresponding thermogravimetric curve also has no obvious change, indicating that the LuO single crystal prepared in Example 1 has good thermal stability at high temperatures and can withstand the extreme environment of higher temperatures. Figure 5 shown. Through calculation, it can be known that its compressive strength reaches 1228.58911 MPa, indicating that the LuO single crystal prepared in Example 1 has excellent mechanical properties and can withstand the extreme environment of higher pressure. 2 O 3 The single crystal has excellent mechanical properties and can withstand the extreme environment of higher pressure.

[0080] To test the thermal stability of the LuO single crystal prepared in Example 1, the LuO single crystal grown in Example 1 was subjected to thermal analysis test, and the results are as 2 O 3 shown. Through the DSC-TGA curve, it can be seen that in the range from room temperature to 1500 °C, there is no obvious endothermic peak in the DSC curve, and the corresponding thermogravimetric curve also has no obvious change, indicating that the LuO single crystal prepared in Example 1 has good thermal stability at high temperatures and can withstand the extreme environment of higher temperatures. 2 O 3 shown. Figure 6 shown. Through the DSC-TGA curve, it can be seen that in the range from room temperature to 1500 °C, there is no obvious endothermic peak in the DSC curve, and the corresponding thermogravimetric curve also has no obvious change, indicating that the LuO single crystal prepared in Example 1 has good thermal stability at high temperatures and can withstand the extreme environment of higher temperatures. 2 O 3 The single crystal has good thermal stability at high temperatures and can withstand the extreme environment of higher temperatures.

[0081] Using the photon cross-section database, for the LuO single crystal prepared in Example 1 and α-Se, CdTe, Si, β-Ga 2 O 3 single crystal and α-Se, CdTe, Si, β-Ga2 O 3 The X-ray absorption coefficient of Figure 9 is theoretically calculated, and the results are as Figure 9 shown. It can be seen from 2 O 3 that in the energy range of 30 - 120 keV, the X-ray absorption coefficient of the Lu 2 O 3 single crystal prepared in Example 1 is significantly higher than that of α-Se, Si, β-Ga

[0082] O 2 O 3 single crystal is obtained by testing the photocurrent data, and the test results are as Figure 10 shown. According to Figure 10 it can be known that the carrier mobility-lifetime product of the Lu 2 O 3 single crystal prepared in Example 1 is 2.3×10 -3 cm 2 V -1 .

[0083] The relationship between the photocurrent and the dose rate at 40 keV X-ray energy is shown in Table 1.

[0084] Table 1 Relationship between photocurrent and dose rate at 40 keV X-ray energy

[0085] Photocurrent (mA) Average dose rate (μGy / s) 10 2.944 12.5 3.657 16 4.682 20 5.897 25 7.429

[0086] Note: Table 1 shows the relationship between the photocurrent and the dose rate of the X-ray emission device at 40 keV X-ray energy. In the detection of the photocurrent curve of the present invention, by controlling the photocurrent in the X-ray emission device, the dose rate of the X-ray emitted by it is controlled; the direct-type X-ray detector generates corresponding photocurrents in the X-ray environment with different dose rates; thus, the photocurrent curve of the direct-type X-ray detector is obtained.

[0087] The photocurrent curves of the direct-type X-ray detector based on the Lu 2 O 3 single crystal prepared in Example 1 at different doses and different bias voltages are as Figure 11 shown. It can be seen from Figure 11 that at the same bias voltage, with the increase of the X-ray dose rate, the photocurrent of the direct-type X-ray detector based on the Lu 2 O 3 single crystal increases continuously.

[0088] The direct-type X-ray detector based on the Lu prepared in Example 12 O 3 The sensitivity of the single-crystal direct X-ray detector under different bias voltages was obtained by Figure 11 fitting the data of current density and dose rate, and the fitting results are as Figure 15 shown. It can be seen from Figure 15 that at a bias voltage of 500 V / cm, the sensitivity of the X-ray detector based on Lu 2 O 3 single crystal is 138.01 μC Gy air -1 cm -2 .

[0089] The detection limit of the X-ray detector based on Lu 2 O 3 single crystal prepared in Example 1 is the dose rate when the signal-to-noise ratio is equal to 3. The results are as Figure 19 shown. The lowest detection limit of the direct X-ray detector based on Lu 2 O 3 single crystal prepared in Example 1 is 8.85 nGy air s -1 .

[0090] The dark current drift curve of the X-ray detector based on Lu 2 O 3 single crystal prepared in Example 1 is as Figure 20 shown. The dark current drift of the direct X-ray detector based on Lu 2 O 3 single crystal prepared in Example 1 is 8.57×10 -10 nA cm -1 s -1 V -1 .

[0091] The preparation of the direct X-ray detector based on Er:Lu 2 O 3 single crystal in Example 2

[0092] The preparation and single crystal growth of a direct X-ray detector based on Er:Lu 2 O 3 single crystal were carried out with reference to Example 1, except that: according to the chemical formula (Er 0.085 Lu 0.915 ) 2 O 3 Er 2 O 3 and Lu 2 O 3 were proportioned, mixed and pressed into a compact, and then crystal growth was carried out. The Er:Lu prepared in this example2 O 3 Single crystal is as follows Figure 2 shown

[0093] Test Example 2: Performance test of direct X-ray detector based on Er:Lu 2 O 3 Performance test of direct X-ray detector based on Er:Lu single crystal

[0094] Based on Er:Lu 2 O 3 The performance test of the direct X-ray detector based on Er:Lu single crystal was carried out with reference to Test Example 1. The photocurrent curves of the direct X-ray detector based on Er:Lu single crystal prepared in Example 2 under different doses and different bias voltages are as 2 O 3 shown, and the current density and dose rate curves are as Figure 12 shown Figure 16 It can be seen from Figure 12 that under the same bias voltage, with the increase of the X-ray dose rate, the photocurrent of the direct X-ray detector based on Er:Lu 2 O 3 single crystal increases continuously, and the sensitivity can reach 194.66 μC Gy air -1 cm -2 .

[0095] Example 3 Preparation of direct X-ray detector based on Ho:Lu 2 O 3 single crystal

[0096] A preparation method of a direct X-ray detector based on Ho:Lu 2 O 3 single crystal and single crystal growth were carried out with reference to Example 1, the difference is that: it is necessary to mix Ho 0.01 Lu 0.99 ), 2 O 3 Mix Ho 2 O 3 and Lu 2 O 3 in proportion, mix them and press them into a block, and then carry out crystal growth. The Ho:Lu 2 O 3 single crystal prepared in this example is as Figure 3 shown

[0097] Test Example 3: Performance test of direct X-ray detector based on Ho:Lu 2 O 3 single crystal

[0098] Based on Ho:Lu 2 O3 The performance test of the direct-type X-ray detector of the single crystal was carried out with reference to Test Example 1. The direct-type X-ray detector based on Ho:Lu prepared in Example 3 2 O 3 The photocurrent curves of the direct-type X-ray detector of the single crystal under different doses and different bias voltages are as Figure 13 shown, and the current density and dose rate curves are as Figure 17 shown. It can be seen from Figure 13 that under the same bias voltage, with the increase of the X-ray dose rate, the photocurrent of the direct-type X-ray detector based on Ho:Lu 2 O 3 single crystal increases continuously, and the sensitivity can reach 232.92 μC Gy air -1 cm -2 .

[0099] Example 4 Preparation of the direct-type X-ray detector based on Yb:Lu 2 O 3 single crystal

[0100] A method for preparing an X-ray detector based on Yb:Lu 2 O 3 single crystal and the single crystal growth were carried out with reference to Example 1, except that: the raw materials need to be proportioned, mixed and pressed into a block according to the chemical formula (Yb 0.02 Lu 0.98 ) 2 O 3 and then crystal growth was carried out. The Yb:Lu 2 O 3 and Lu 2 O 3 single crystal prepared in this example is as 2 O 3 shown in Figure 4 .

[0101] Test Example 4: Performance test of the direct-type X-ray detector based on Yb:Lu 2 O 3 single crystal

[0102] The performance test of the direct-type X-ray detector based on Yb:Lu 2 O 3 single crystal was carried out with reference to Test Example 1. The direct-type X-ray detector based on Yb:Lu prepared in Example 4 2 O 3 single crystal under different doses and different bias voltages are as Figure 14 shown, and the current density and dose rate curves are as Figure 18 shown. It can be seen from Figure 14It can be seen that under the same bias voltage, as the X-ray dose rate increases, the photocurrent of the X-ray detector based on Yb:Lu 2 O 3 single crystal continuously increases, and the sensitivity can reach 160.09 μC / Gy air -1 cm -2 。

[0103] Example 5 Preparation of a direct X-ray detector based on (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 crystal

[0104] The preparation of a direct X-ray detector based on (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 crystal and crystal growth are carried out with reference to Example 1, the difference is that: it is necessary to mix Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 Sc 2 O 3 、Y 2 O 3 and Lu 2 O 3 in proportion, mix and press into a compact, and then carry out crystal growth.

[0105] The direct X-ray detector based on (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 crystal prepared in this example has a continuously increasing photocurrent as the X-ray dose rate increases under the same bias voltage, and the sensitivity is similar to that of the direct X-ray detector prepared in Example 1.

[0106] Example 6 Preparation of a direct X-ray detector based on (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 ceramic

[0107] (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3The preparation process of the ceramic refers to Example 1 in Patent CN117088680A. A direct X-ray detector based on (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 ceramic is prepared with reference to Example 1.

[0108] The direct X-ray detector based on (Sc 0.33 Y 0.33 Lu 0.34 ) 2 O 3 ceramic prepared in this example, under the same bias voltage, as the X-ray dose rate increases, the photocurrent continuously increases, and the sensitivity is similar to that of the direct X-ray detector prepared in Example 1.

[0109] Example 7: Preparation of a direct X-ray detector based on Lu 2 O 3 ceramic

[0110] The preparation process of Lu 2 O 3 ceramic refers to Example 1 in Patent CN117088680A. The preparation of a direct X-ray detector based on Lu 2 O 3 ceramic is prepared with reference to Example 1.

[0111] The direct X-ray detector based on Lu 2 O 3 ceramic prepared in this example, under the same bias voltage, as the X-ray dose rate increases, the photocurrent continuously increases, and the sensitivity is similar to that of the direct X-ray detector prepared in Example 1.

[0112] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A direct X-ray detector, characterized in that: It includes a sesquioxide, a positive electrode layer and a negative electrode layer, wherein the sesquioxide is arranged between the positive electrode layer and the negative electrode layer; The sesquioxide includes any one of sesquioxide crystal, sesquioxide ceramic and sesquioxide glass.

2. The direct X-ray detector according to claim 1, characterized in that: The thickness of the sesquioxide is 0.5-1.5 mm, preferably 0.8-1.2 mm.

3. The direct X-ray detector according to claim 1, characterized in that: The sesquioxide is a sesquioxide crystal; Preferably, the chemical formula of the sesquioxide crystal is (Re a Sc b Y c Lu d )2O3, wherein a+b+c+d=1, and 0≤a≤0.1, 0≤b,c,d≤1, and Re is selected from any one of ytterbium, erbium, holmium, thulium, europium, dysprosium, samarium and neodymium; Preferably, the chemical formula of the sesquioxide crystal is (Re a Lu 1-a )2O3, wherein 0≤a≤0.1, and Re is selected from any one of ytterbium, erbium, holmium, thulium, europium, dysprosium, samarium and neodymium; Preferably, the sesquioxide crystal is a lutetium oxide single crystal; Preferably, the lutetium oxide single crystal is a single crystal in the (111) direction, belongs to the cubic system, and has a space group of Ia. - 3. α=90°, β=90°, γ=90°; Preferably, the positive electrode layer is arranged on the upper surface of the lutetium oxide single crystal in the (111) direction, and the negative electrode layer is arranged on the lower surface of the lutetium oxide single crystal in the (111) direction.

4. The direct X-ray detector according to claim 1, characterized in that: The materials of the positive electrode layer and the negative electrode layer are selected from any one of gold, platinum, molybdenum and tungsten; Preferably, the material of the positive electrode layer is gold, and the thickness of the positive electrode layer is 50-150 nm, preferably 80-120 nm; Preferably, the material of the negative electrode layer is gold, and the thickness of the negative electrode layer is 50-150 nm, preferably 80-120 nm.

5. A method for preparing a direct X-ray detector according to any one of claims 1 to 4, characterized in that: include: The positive electrode layer and the negative electrode layer are deposited on the surface of the sesquioxide by ion sputtering to obtain a direct X-ray detector.

6. The preparation method according to claim 5, characterized in that: The sesquioxide is a sesquioxide crystal, and its chemical formula is (Re a Sc b Y c Lu d )2O3, wherein a+b+c+d=1, and 0≤a≤0.1, 0≤b,c,d≤1, and Re is selected from any one of ytterbium, erbium, holmium, thulium, europium, dysprosium, samarium and neodymium; The method for preparing the sesquioxide crystal comprises the following steps: The raw materials are pressed into blocks and crystal growth is carried out using the melt method; Preferably, the raw material purity is greater than or equal to 99.999%.

7. The preparation method according to claim 6, characterized in that: The pressing is performed by isostatic pressing at 150-250 MPa for 100-150 s; preferably, at 170-220 MPa for 100-140 s; further preferably, at 190-210 MPa for 110-130 s.

8. The preparation method according to claim 6, characterized in that: The melt method includes any one of a Czochralski method, a film-guiding method and a temperature gradient method; Preferably, the pulling method includes: the crystal growth atmosphere is a mixed atmosphere of Ar and H2, the seed crystal is a pure R2O3 seed crystal, the heating method is coil induction heating, the pulling speed is 0.5-5mm / h, the rotation speed is 10-30rpm; R is selected from any one of Lu, Sc, and Y; further preferably, when R is Lu, the seed crystal is <111> or <100> Direction of pure lutetium oxide seed crystals; Preferably, the film-conducting method includes: the crystal growth atmosphere is a mixed atmosphere of Ar and H2, the seed crystal is a pure R2O3 seed crystal, the heating method is coil induction heating, the pulling speed is 0.3-6mm / h, and the rotation speed is 8-38rpm; R is selected from any one of Lu, Sc, and Y; further preferably, when R is Lu, the seed crystal is <111> or <100> Direction of pure lutetium oxide seed crystals; Preferably, the temperature gradient method includes: the crystal growth atmosphere is a mixed atmosphere of Ar and H2, no seed crystal is used during crystal growth, or pure R2O3 seed crystal is placed at the bottom of the crucible, R is selected from any one of Lu, Sc, and Y, or top seed crystal is used to induce crystallization, and the heating method is coil induction heating, and the temperature is reduced at a rate of 15-25K / h to induce crystal crystallization; further preferably, when R is Lu, the pure R2O3 seed crystal is <111> or <100> Direction of pure lutetium oxide seed crystals; Further preferably, when the temperature gradient method is used for crystal growth, a top rhenium seed crystal is used to induce crystallization.

9. The preparation method according to claim 8, characterized in that: After the crystal growth is completed, the crystal is taken out from the crucible, annealed in an air atmosphere, and oriented and polished to obtain a sesquioxide crystal; Preferably, the annealing is performed at 1600-1700° C. for 48-50 hours.

10. Application of the direct X-ray detector according to any one of claims 1 to 4 or the direct X-ray detector prepared by the preparation method according to any one of claims 5 to 9 in X-ray detection in extreme environments; Preferably, the extreme environments include nuclear reactors, deep space environments and deep sea environments.

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