High-temperature-resistant vacuum ultraviolet imaging system based on nano polycrystalline boron nitride scintillator

Abstract

The invention belongs to the technical field of vacuum ultraviolet imaging, and particularly relates to a high-temperature-resistant vacuum ultraviolet imaging system based on a nano polycrystalline boron nitride scintillator, which comprises a nano polycrystalline boron nitride scintillator assembly, an imaging lens and a visible light imaging device. The nano polycrystalline boron nitride scintillator assembly is composed of a nano polycrystalline boron nitride scintillator with high luminescence robustness and a heat-conducting transparent substrate and can convert vacuum ultraviolet light into visible light signals in a high-temperature environment, and the imaging lens is matched with the visible light imaging device and used for receiving and recording scintillation light signals. And the thermal protection shell is used for isolating an external high-temperature environment, so that the internal detection system normally works within a set temperature range. The invention provides a reliable and efficient solution for realizing vacuum ultraviolet imaging in an extreme high-temperature environment, and has an important application prospect in frontier fields such as solar storm monitoring and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vacuum ultraviolet (VUV) imaging, and particularly relates to a high-temperature-resistant vacuum ultraviolet imaging system based on a nano-polycrystalline boron nitride scintillator. BACKGROUND

[0002] Solar storm refers to a large number of charged particle streams released by solar flares and coronal mass ejections, which impact the Earth's space environment at high speed and can cause ionospheric disturbances, magnetic storms and aurora phenomena, and seriously interfere with satellite communication, navigation systems and even power grid safety. In order to provide early warning for such disastrous space weather events, it is urgent to establish a real-time monitoring system for solar activity to achieve early warning of disaster events. Vacuum ultraviolet light (VUV, 10-200 nm) has become a core technology for monitoring solar storms due to its extremely low solar background noise and the inclusion of key diagnostic spectral lines of solar storms.

[0003] The scintillator type VUV imaging system utilizes fluorescence conversion mechanism to efficiently convert high-energy VUV photons into longer wavelength visible light photons, and then the rear-end photoelectric imaging system is used for signal acquisition and spatial distribution reconstruction. However, the detector deployed in the sun-synchronous orbit needs to withstand severe temperature alternation, and the temperature stability and photon conversion efficiency of the scintillator directly receiving VUV photon signals directly determine the imaging quality and reliability of the scintillator in extreme environments. Unfortunately, most traditional scintillators will have serious thermal quenching, lattice phase transition or chemical decomposition under high-temperature working conditions, resulting in a significant degradation or even failure of the detection efficiency, which seriously restricts the continuous monitoring capability under high-temperature working conditions.

[0004] Therefore, it is necessary to develop a VUV imaging system capable of stable operation in a high-temperature radiation environment. SUMMARY

[0005] In order to overcome the deficiencies of the prior art, the present application provides a high-temperature-resistant VUV imaging system based on a nano-polycrystalline boron nitride (NPBN) scintillator. Figure 1), aiming to solve the technical problem of performance degradation or failure of traditional imaging systems in high-temperature VUV radiation environment. The present application adopts high-luminous-robust NPBN scintillator as the core detection element, and is matched with a heat-conducting transparent substrate, so that the scintillator can realize efficient heat dissipation while receiving VUV photons and converting them into visible light signals, thereby ensuring stable operation in high-temperature environment. The NPBN scintillator has high luminescence quantum yield (75.1%), high thermal quenching temperature (720 K), high thermal conductivity and excellent thermal stability, so that it can maintain performance without attenuation under extreme high-temperature conditions, effectively overcoming the defect of insufficient high-temperature resistance of traditional scintillator materials. The imaging system further comprises an imaging lens, a visible light imaging device and a thermal protection shell. The thermal protection shell is used to isolate the external high temperature and ensure that the internal components work normally within the set temperature range. The present application provides a reliable and efficient solution for VUV imaging in extreme high-temperature environment, and has important application prospects in the field of solar storm monitoring and other frontier fields.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is: The present application provides a high-temperature-resistant vacuum ultraviolet imaging system based on nano-polycrystalline boron nitride scintillator, which comprises a nano-polycrystalline boron nitride scintillator assembly, an imaging lens and a visible light imaging device; wherein, The nano-polycrystalline boron nitride scintillator assembly is composed of a high-luminous-robust nano-polycrystalline boron nitride scintillator and a heat-conducting transparent substrate coaxially, for receiving vacuum ultraviolet light in high-temperature environment and converting it into visible light signals; The imaging lens is used to receive the visible light signals and perform optical transmission; The visible light imaging device is used to receive the scintillation light processed by the imaging lens and record the photon information.

[0007] Further, the nano-polycrystalline boron nitride scintillator in the nano-polycrystalline boron nitride scintillator assembly is closely attached to the heat-conducting transparent substrate to realize efficient heat conduction of the scintillator assembly.

[0008] Still further, the heat-conducting transparent substrate is diamond or silicon carbide. Diamond (thermal conductivity about 2000 W / (m·K)) and silicon carbide (thermal conductivity 360~490 W / (m·K)) are materials with ultra-high thermal conductivity and excellent optical transparency. The heat-conducting transparent substrate provides a heat dissipation path for the scintillator, which can quickly conduct heat out and stabilize its working temperature; at the same time, its high transparency ensures low loss transmission of scintillation light.

[0009] Furthermore, the high-temperature resistant vacuum ultraviolet imaging system also includes a thermal protection shell, which is used to isolate the external high-temperature environment and enable the internal system to operate normally within a set temperature range. The thermal protection shell is made of carbon fiber reinforced composite material or aerogel material.

[0010] Furthermore, the nanocrystalline boron nitride scintillator is prepared by the following steps: (1) Use sapphire or graphite as a substrate and fix it with a graphite clamp; (2) Place the fixed substrate in a vertical chemical vapor deposition furnace, evacuate it, and then heat it to the reaction temperature from the side. (3) NH3 and BCl3 or NH3 and BF3 raw material gas are introduced into the furnace, and N2 is used as the carrier gas; (4) After ventilation, keep the gas flow rate and temperature constant; finally, turn off the power to allow the deposition system to cool naturally to room temperature. (5) The grown nano-polycrystalline boron nitride film is peeled off from the substrate, and after surface polishing and ultrasonic cleaning, it is cut to a predetermined size to obtain the nano-polycrystalline boron nitride scintillator.

[0011] Furthermore, in step (2), the reaction temperature is 1300~1500 ℃.

[0012] Furthermore, in step (3), the volume ratio of NH3 and BCl3, or NH3 and BF3 raw material gases is 1.1~1.3:1.

[0013] Furthermore, in step (4), the temperature is maintained for 15 to 25 hours.

[0014] Furthermore, the thermal protection housing is provided with a window, the nano-polycrystalline boron nitride scintillator assembly is fixed on the window of the thermal protection housing, and the imaging lens and visible light imaging device are installed inside the thermal protection housing. Vacuum ultraviolet light in a high-temperature environment irradiates the nano-polycrystalline boron nitride scintillator, and the fluorescence signal generated by the scintillator is collected and imaged by the imaging lens and visible light imaging device after passing through the thermally conductive transparent substrate.

[0015] Furthermore, the imaging system is also suitable for imaging detection of X-rays, neutrons, electrons or protons, and to avoid damage caused by direct irradiation of the visible light imaging device by high-energy particles, the system has a reflector in the path of the imaging lens to reflect the scintillation light onto the camera for imaging.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a high-temperature resistant vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator. Figure 1This invention addresses the technical problem of performance degradation or failure of traditional imaging systems under high-temperature VUV radiation environments. The system innovatively employs a highly robust, luminescent nanocrystalline boron nitride scintillator as the core detection element, maintaining stable luminescence performance even in extreme high-temperature environments. Furthermore, through a composite structure design of the nanocrystalline boron nitride scintillator and a thermally conductive transparent substrate, it achieves efficient conversion from vacuum ultraviolet light to visible light while significantly improving the system's heat dissipation capacity, ensuring long-term operational reliability at high temperatures. The imaging system also includes an imaging lens, a visible light imaging device, and a thermally protective housing. The thermally protective housing isolates the system from external high temperatures, ensuring that internal components operate normally within a set temperature range. This invention provides a reliable and efficient solution for VUV imaging under extreme high-temperature environments, and has significant application prospects in cutting-edge fields such as solar storm monitoring. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a high-temperature resistant VUV imaging system based on an NPBN scintillator.

[0018] Figure 2 This is a photograph of the 8-inch NPBN scintillator in Example 1.

[0019] Figure 3 The image shows the XRD pattern of the NPBN scintillator in Example 1.

[0020] Figure 4 (a) Low-magnification TEM image and selected area electron diffraction pattern of the NPBN scintillator in Example 1, and (b) High-resolution cross-sectional TEM image.

[0021] Figure 5 The PL spectrum of (a) and PLQY of (b) of the NPBN scintillator in Example 1 under 266 nm laser excitation are shown.

[0022] Figure 6 The image shows the fluorescence of the NPBN scintillator in Example 1 under 254 nm LED illumination, with a commercial YAG:Ce scintillator placed in the upper right corner for comparison.

[0023] Figure 7 The graph shows the changes in luminescence intensity of NPBN, NaSal, and YAG:Ce as a function of temperature in Example 2. The luminescence intensity of the three samples has been calibrated, and the excitation source is a 266 nm continuous laser.

[0024] Figure 8 The images show the luminescence of (a) NPBN, (b) NaSal, and (c) YAG:Ce at high temperatures in Example 3, where the excitation source was a 266 nm continuous laser. NPBN and YAG:Ce were heated to 673 K, and NaSal was heated to 523 K.

[0025] Figure 9 The images shown are (a) photographs of the imaged object and (b) photographs and schematic diagrams of the scintillator heating device used in the high-temperature VUV imaging test in Example 3.

[0026] Figure 10 Examples 3 are: (a) VUV imaging results of an NPBN scintillator operating at 298 K, 373 K, 473 K, and 523 K; and (b) VUV imaging results of a commercially available NaSal scintillator operating at 298 K, 373 K, 473 K, and 523 K, wherein the NaSal scintillator was obtained by solution coating on a glass slide.

[0027] Figure 11 (a) An optical photograph of an aircraft turbine engine blade in Example 4. (b) Based on 298 K and 523 K. 6 Neutron images taken from LiF / ZnS scintillators. (c) Neutron images taken from NPBN scintillators at 298 K and 573 K.

[0028] Figure 12 In Example 4 6 Morphological comparison of LiF / ZnS and NPBN scintillators before and after high-temperature neutron imaging experiments. Detailed Implementation

[0029] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0031] In the following examples, cerium-doped yttrium aluminum garnet (YAG:Ce) crystals were obtained from the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences; sodium salicylate (NaSal) powder was obtained from Maclean Biotechnology Co., Ltd., and was tested after tableting.

[0032] Example 1: Preparation and characterization of nanocrystalline boron nitride (NPBN) scintillators An 8-inch NPBN scintillator with a micrometer-thickness was grown on a graphite substrate using a self-designed vertical chemical vapor deposition furnace. The specific growth steps are as follows: An 8-inch graphite substrate, fixed on a graphite fixture, was placed in the reaction chamber, and a vacuum was drawn to a base pressure of 10 Pa. The furnace temperature was then raised to 1450 °C and maintained stable. At this temperature, NH3 and BCl3 were introduced at a volume ratio of 1.25:1, with N2 as the carrier gas. The system pressure was maintained at 50 Pa during the reaction, and growth continued for 20 h. After growth, the power was cut off, and the sample was allowed to cool naturally with the furnace. The resulting NPBN film could be easily peeled off from the graphite substrate. After mechanical polishing and cleaning, a self-supported scintillator sample with a diameter of 8 inches and a uniform thickness of 300 μm was obtained, and its macroscopic morphology is shown below. Figure 2 As shown, it is a self-supporting sample with high transparency.

[0033] Structural characterization results show that this NPBN scintillator has a typical hexagonal structure. X-ray diffraction (XRD) spectra measured using a PANalytical X'Pert Pro diffractometer (Cu-Kα radiation) show that the main diffraction peak is located at 25.9°, slightly shifted compared to the standard diffraction peak of hexagonal boron nitride (hBN) (26.7°). This shift may be due to internal stress and lower crystallinity. Transmission electron microscopy (TEM) sample preparation was performed using the ion gun of a FEI Helios 5 UX focused ion beam scanning electron microscope (FIB-SEM). Cross-sectional TEM images of the NPBN scintillator were obtained using a FEI Talos F200X TEM microscope, including low-magnification TEM images, selected area electron diffraction patterns, and high-resolution TEM images. Figure 5 As shown. Low-magnification TEM images show that NPBN is distributed in a flocculent manner and has a small grain size; selected area electron diffraction patterns show typical polycrystalline diffraction rings, confirming its nanopolycrystalline structure, among which the most obvious diffraction ring can be identified as the (002) crystal plane of hBN; high-resolution TEM images further show that the material is composed of tiny grains with a size of about 1-5 nm.

[0034] The room-temperature photoluminescence (PL) characteristics of NPBN scintillators were characterized using a self-built deep ultraviolet optical path system. The excitation source was a CryLas FQCW 266 continuous laser (266 nm), and the emission spectrum was acquired using an OceanOptics QE65PRO scientific spectrometer (200-1000 nm). The obtained PL spectra of the NPBN scintillators are shown below. Figure 5As shown in Figure a, it can be seen that under 266 nm laser excitation, the NPBN scintillator exhibits broad-spectrum emission in the 300-600 nm wavelength range, with a peak at 387 nm. The luminescent quantum yield (PLQY) of the scintillator was obtained using the Hamamatsu Quantaurus-QY absolute luminescence quantum spectrometer. Figure 5 As shown in b, the PLQY of the NPBN scintillator was as high as 75.1% under 300 nm excitation. The fluorescence image of the NPBN scintillator under 254 nm LED illumination is shown in Figure b. Figure 6 As shown, a commercial VUV scintillator cerium-doped yttrium aluminum garnet (YAG:Ce) wafer is placed in the upper right corner for comparison. It can be seen that the NPBN scintillator emits blue-violet fluorescence under deep ultraviolet LED excitation, and its luminescence intensity is significantly higher than that of the YAG:Ce scintillator.

[0035] Example 2: Evaluation of the high-temperature luminescence performance of nanocrystalline boron nitride (NPBN) scintillators The temperature-dependent photoluminescence (PL) characteristics of NPBN scintillators were characterized using a self-built deep ultraviolet (DUV) optical path system. A Linkam THMS600 thermostat with electric heating and liquid nitrogen cooling was used to strictly control the sample temperature. The test temperature range was 80-840 K, with a temperature gradient of 20 K. Before the experiment, the thermostat chamber was purged with nitrogen to remove air and prevent water vapor condensation at low temperatures from interfering with the test results. The temperature-dependent PL spectra of the NPBN scintillators were measured, and comparisons were made with commercially available VUV scintillators YAG:Ce and sodium salicylate (NaSal). Figure 7 The study showed that the luminescence intensity of the three scintillators varies with temperature. NPBN exhibits the highest PL intensity in the range from room temperature to high temperature, and its intensity decay rate with increasing temperature is significantly lower than that of the comparative materials. By extracting the temperature at which the PL intensity drops to half of its maximum value (thermal quenching temperature), the thermal quenching temperatures of NPBN, YAG:Ce and NaSal are quantitatively obtained to be approximately 720 K, 620 K and 520 K, respectively.

[0036] To visually verify the high-temperature luminescence stability, the NPBN scintillator was heated in an air atmosphere by a resistance furnace, with the temperature monitored in real time using commercial thermocouples. A 266 nm continuous laser was selected as the excitation source and focused onto the scintillator. NPBN and YAG:Ce were heated to 673 K, and NaSal to 523 K. High-temperature luminescence images of NPBN, NaSal, and YAG:Ce, captured using a Nikon D850 camera, are shown below. Figure 8 As shown, at 673 K, the luminescence intensity of NPBN is significantly higher than that of YAG:Ce; while NaSal, due to insufficient thermal stability, undergoes carbonization and deactivation (complete quenching of luminescence) at 523 K, indicating that it is unsuitable for high-temperature applications. It should be noted that...Figure 7 The high-temperature PL data (up to 680 K) of the NaSal were measured under nitrogen protection to avoid carbonization. These results demonstrate the high robustness of NPBN scintillators in luminescence. Furthermore, boron nitride itself possesses high thermal stability, excellent thermal conductivity, and superior radiation resistance, enabling it to effectively resist heat accumulation and radiation damage during device operation, thereby ensuring long-term structural integrity and performance reliability.

[0037] Example 3: VUV High-Temperature Imaging Performance Test of Nanocrystalline Boron Nitride (NPBN) Scintillators The VUV imaging testing system uses an EX5 / 250 ArF excimer laser (193 nm) as the VUV light source. After filtering out stray light other than 193 nm with a prism, the beam is expanded by an ultraviolet lens and projected onto the surface of the object being imaged. The object being imaged is a perforated metal mask, such as... Figure 9 As shown in Figure a. A scintillator is placed behind the imaging object, and the fluorescence signal generated by the scintillator is collected by an AndoriKon-M camera. To study the temperature effect, a self-made heating device is used to control the temperature of the scintillator, such as... Figure 9 As shown in b, its core structure includes a ceramic heating element, a multi-layer copper plate, a semi-insulating silicon carbide substrate, a thermocouple, an aerogel insulation board, a power supply, a relay, and a PID temperature controller. The copper plate, due to its excellent thermal conductivity and machinability, is chosen as the support structure for the scintillator. Its central hollow design accommodates the scintillator and the semi-insulating silicon carbide substrate, ensuring light transmittance. The ceramic heating element is embedded within the multi-layer copper plate, heating the scintillator laterally and avoiding direct obstruction of the beam path. The semi-insulating silicon carbide substrate, with its high thermal conductivity, rapidly transfers heat to the scintillator, effectively reducing the temperature gradient in the scintillator's working area while maintaining high transmittance. The outer layer of the device uses a multi-layer aerogel insulation board to wrap the copper plate, significantly reducing heat radiation and achieving high insulation performance. The heating element achieves precise temperature control through the power supply, relay, and PID temperature controller. It is worth noting that the thermally conductive transparent substrate placed behind the scintillator can be silicon carbide or diamond. In high-temperature VUV imaging systems, the primary function is efficient heat dissipation while ensuring light signal transmission. However, in the self-made heating device of this embodiment, its function is to rapidly and uniformly transfer heat to the scintillator while maintaining excellent optical transmittance. A commercially available NaSal powder scintillator was selected as a reference. It was uniformly coated onto a glass substrate using a solution coating method to prepare a large-area scintillator, which was then tested under the same high-temperature experimental conditions.

[0038] Figure 10VUV images captured by NPBN and NaSal scintillators at different operating temperatures (298 K, 373 K, 473 K, and 523 K) are presented. The observations show that at 573 K, the VUV images based on the NPBN scintillator maintain high image quality; in stark contrast, the NaSal scintillator completely fails under the same high-temperature conditions and cannot perform effective VUV imaging. Therefore, the above comparative experiments clearly demonstrate that the NPBN scintillator has significant advantages over the traditional NaSal scintillator in high-temperature VUV imaging applications, exhibiting superior thermal stability and reliable high-temperature performance.

[0039] Example 5: High-Temperature Neutron Imaging Test of Nanocrystalline Boron Nitride (NPBN) Scintillators because 10 B spectroscopy possesses an absorption cross-section as high as 3840 barn for thermal neutrons, and its abundance in nature is as high as 19.8%, giving NPBN scintillators excellent neutron detection potential. In nuclear reactors, the generation, transport, and absorption processes of neutrons directly determine the nuclear reaction process and the reactor's operating status. Neutron imaging technology is crucial for assessing reactor operating status, detecting anomalies, and optimizing reactor design. However, the operating temperature of nuclear reactor cores typically exceeds 600 K, which places stringent requirements on the high-temperature resistance of neutron imaging systems, especially their neutron scintillators. Therefore, this study also conducted high-temperature neutron imaging verification experiments on NPBN scintillators using a self-built heating device, comparing its neutron imaging performance under both room temperature and high-temperature conditions.

[0040] The neutron source originated from the China Advanced Research Reactor (CARD) at the China Institute of Atomic Energy, and the imaging experiment was conducted at the Cold Neutron Imaging Facility. During the experiment, the reactor power was 30 MW, and the neutron flux at the scintillator was 10 MW. 7 neutrons / cm 2 This invention independently designed and manufactured a specialized heating device adapted to a neutron scintillator, fixing the NPBN scintillator onto an aluminum plate of the heating device. This heating device is similar to those used in VUV imaging, but it does not require a hollowed-out section in the aluminum plate to house the scintillator. Due to the small thermal neutron trapping cross-section of aluminum, neutrons can directly pass through the aluminum plate and irradiate the scintillator. The neutron imaging system consists of a thermally controlled scintillator assembly, a reflector, and a scientific-grade CCD camera. The experiment used the turbine blades of a Boeing 737 aircraft engine, which have a complex internal structure, as the imaging object. Optical photographs of the aircraft turbine engine blades are shown below. Figure 11 As shown in figure a, neutron images of the NPBN scintillator at 298 K and 573 K were captured using a heating device for temperature control. For performance comparison, commercially available [materials / technology] were used. 6 LiF / ZnS neutron scintillator. Temperature was controlled using a heating device, and images were taken. 6Neutron images of the LiF / ZnS scintillator at 298 K and 523 K. Five neutron images were captured consecutively at each target temperature, with an exposure time of 30 s. All images were normalized using a straight-through beam with the same parameters (same exposure time).

[0041] Based on 298 K and 523 K 6 Neutron images taken from LiF / ZnS scintillators, such as Figure 11 As shown in b, neutron images taken based on NPBN scintillators at 298 K and 573 K are as follows. Figure 11 As shown in c. 6 The LiF / ZnS scintillator completely failed at 523 K, failing to reveal the outline and internal structure of the imaged object, confirming its severe degradation under high-temperature conditions. In contrast, the NPBN scintillator maintained excellent thermal stability at high temperatures; neutron images acquired at 573 K still clearly resolved the internal air-cooled hollow structure of the turbine blades, showing no significant resolution degradation. Furthermore, we compared the morphology of the scintillators before and after the high-temperature neutron imaging experiment, such as... Figure 12 As shown in the image. Experiments revealed that after high-temperature treatment, the color, originally white... 6 The LiF / ZnS scintillator turns brown, while the NPBN scintillator remains largely unchanged in appearance. This significant color change indicates the effect of high temperature on... 6 The LiF / ZnS scintillator exhibited irreversible effects. These results fully demonstrate the significant technical advantages of NPBN scintillators in high-temperature radiation detection applications.

[0042] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A vacuum ultraviolet imaging system based on nanocrystalline boron nitride scintillators, characterized in that, The vacuum ultraviolet imaging system includes a nanocrystalline boron nitride scintillator assembly, an imaging lens, and a visible light imaging device; wherein... The nano-polycrystalline boron nitride scintillator assembly is composed of a nano-polycrystalline boron nitride scintillator and a thermally conductive transparent substrate, and is used to receive vacuum ultraviolet light under high temperature environment and convert it into visible light signal. The imaging lens is used to receive the visible light signal and perform optical transmission; The visible light imaging device is used to receive the scintillation light processed by the imaging lens and record photon information.

2. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 1, characterized in that, In the nanocrystalline boron nitride scintillator assembly, the nanocrystalline boron nitride scintillator is bonded to a thermally conductive transparent substrate to achieve heat conduction of the scintillator assembly.

3. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 2, characterized in that, The thermally conductive transparent substrate is made of diamond or silicon carbide.

4. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 1, characterized in that, The vacuum ultraviolet imaging system also includes a thermal protection shell, which is used to isolate the external high-temperature environment and enable the internal system to operate normally within a set temperature range. The thermal protection shell is made of carbon fiber reinforced composite material or aerogel material.

5. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 4, characterized in that, The nanocrystalline boron nitride scintillator is prepared by the following steps: (1) Use sapphire or graphite as a substrate and fix it with a graphite clamp; (2) Place the fixed substrate in a vertical chemical vapor deposition furnace, evacuate it, and then heat it to the reaction temperature from the side. (3) NH3 and BCl3 or NH3 and BF3 raw material gas are introduced into the furnace, and N2 is used as the carrier gas; (4) After ventilation, keep the gas flow rate and temperature constant; finally, turn off the power to allow the deposition system to cool naturally to room temperature. (5) The grown nano-polycrystalline boron nitride film is peeled off from the substrate, and after surface polishing and ultrasonic cleaning, it is cut to a predetermined size to obtain the nano-polycrystalline boron nitride scintillator.

6. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 5, characterized in that, In step (2), the reaction temperature is 1300~1500 ℃.

7. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 5, characterized in that, In step (3), the volume ratio of NH3 and BCl3, or NH3 and BF3 raw material gases is 1.1~1.3:

1.

8. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to claim 5, characterized in that, In step (4), the temperature is maintained for 15 to 25 hours.

9. The vacuum ultraviolet imaging system based on a nanocrystalline boron nitride scintillator according to any one of claims 4-8, characterized in that, The thermal protection shell is provided with a window, and the nano-polycrystalline boron nitride scintillator assembly is fixed on the window of the thermal protection shell. The imaging lens and visible light imaging device are installed inside the thermal protection shell. Vacuum ultraviolet light in a high-temperature environment irradiates the nano-polycrystalline boron nitride scintillator. The fluorescence signal generated by the scintillator is excited and passes through the thermally conductive transparent substrate, and is collected and imaged by the imaging lens and visible light imaging device.

10. The high-temperature vacuum ultraviolet imaging system based on nanocrystalline boron nitride scintillator according to claim 1, characterized in that, The imaging system is also suitable for imaging detection of X-rays, neutrons, electrons or protons. In order to avoid damage caused by direct irradiation of the visible light imaging device by high-energy particles, the system has a reflector in the path of the imaging lens to reflect the scintillation light onto the visible light imaging device for imaging.

Images