Pulse radiation detection device and system based on near-infrared scintillator

Abstract

The invention discloses a pulse radiation detection device and system based on a near-infrared scintillator, and solves the technical problems of overlarge scintillation light attenuation and time broadening, limited detection distance and the like of an existing pulse radiation detection device. The detection device comprises a near-infrared scintillator, an optical fiber bundle and a photoelectric detector, the near-infrared scintillator is of a sheet-shaped structure and is used for receiving pulse radiation and emitting near-infrared scintillation light pulses. The optical fiber bundle is formed by gluing a plurality of single-mode optical fibers or multimode optical fibers which are equal in length and are mutually independent in parallel; the input end of the optical fiber bundle is attached to the light-emitting face of the near-infrared scintillator. The output end of the optical fiber bundle is connected with the photoelectric detector; the optical fiber bundle is used for coupling the near-infrared scintillation light pulse and then transmitting to the photoelectric detector; the photoelectric detector is a near-infrared photoelectric detector and is used for converting a near-infrared scintillation light pulse into an electric pulse. According to the detection device, near-infrared scintillation light can be efficiently coupled into the optical fiber bundle, and low-attenuation and high-time-resolution transmission is carried out.

Description

Technical Field

[0001] The present invention relates to a pulse radiation detection device, and in particular to a device and a system for realizing pulse radiation detection through a near-infrared scintillator. Background Art

[0002] Pulsed radiation refers to pulses of radiation lasting microseconds or less, consisting of a large number of X-ray / gamma photons, neutrons, and charged particles. Pulsed radiation detectors can record the intensity and duration of these pulses, providing accurate test data for related research. Pulsed radiation detection devices, which convert pulsed radiation into electrical pulses, are currently widely used in pulsed radiation monitoring, radioactive material processing, and environmental monitoring.

[0003] Traditional pulse radiation detection devices are susceptible to interference from stray pulse radiation during operation, resulting in a deterioration in their detection signal-to-noise ratio and a reduced service life. To address these issues, a common approach is to surround the pulse radiation detection device with a large amount of shielding. Another solution is to transmit the pulse signal via optical fiber to a location away from the pulse radiation source and then record it, thereby achieving pulse radiation detection. Compared with traditional pulse radiation detection devices, this type of detection device has the following advantages: First, the front-end detection unit has a relatively simple structure and small size, allowing for the arrangement of multiple detectors within a limited space, thereby improving the integration of the test system. Second, compared with cables of the same length, optical fiber has a higher analog bandwidth potential, reaching GHz. However, cables hundreds of meters long require compensation bandwidth to transmit gamma signals to 200 MHz, and the signal amplitude also suffers from significant attenuation. Third, optical fiber is much smaller than electrical cables, allowing it to transmit more signals within the same volume. Fourth, placing highly sensitive optoelectronic devices at the rear end, away from the radiation pulse source, eliminates the need for radiation shielding, thereby reducing shielding costs. However, this type of pulse radiation detection device also has the following problems:

[0004] First, the luminescence center of the scintillation material used in the pulse radiation detection device does not match the transmission window of the optical fiber. The low-loss, high-bandwidth window of the optical fiber is generally around 850nm, 1310nm, and 1550nm, while the luminescence center of most scintillation materials is concentrated in the range of 350nm to 500nm. When transmitting over long distances (tens to hundreds of meters), the scintillation light generated by these scintillation materials faces extremely high attenuation and dispersion in the optical fiber, resulting in excessive attenuation and time broadening of the scintillation light of the pulse radiation detector, ultimately making the remote transmission and re-detection plan impossible to implement.

[0005] Second, the luminous efficiency of existing near-infrared scintillation materials is low. A common solution is to use large-core optical fibers with a core diameter of hundreds of microns to transmit signals to improve light collection efficiency. However, large-core optical fibers have severe inter-modal dispersion. To keep the dispersion small, the length of large-core optical fibers can only be a few meters, which cannot achieve long-distance detection of tens or even hundreds of meters, let alone the detection of near-infrared light. Therefore, its scope of application is limited. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problems of existing pulse radiation detection devices that use optical fiber to transmit signals, such as excessive scintillation light attenuation and time broadening, limited detection distance, and inability to detect near-infrared light, and to provide a pulse radiation detection device and system based on near-infrared scintillators.

[0007] To achieve the above objectives, the technical solutions provided by the present invention are as follows:

[0008] A pulse radiation detection device based on near-infrared scintillator, which is special in that:

[0009] Including near-infrared scintillator, fiber optic bundle and photodetector;

[0010] The near-infrared scintillator is a thin sheet structure, one side of which is an incident surface for receiving pulse radiation, and the other side is a light-emitting surface for emitting near-infrared scintillation light pulses;

[0011] The optical fiber bundle is formed by gluing together a number of independent single-mode optical fibers or multi-mode optical fibers of equal length. The input end of the optical fiber bundle is aligned with the light-emitting surface of the near-infrared scintillator and has an area smaller than that of the light-emitting surface of the near-infrared scintillator. The output end of the optical fiber bundle is connected to the photodetector, and the center of the output end is on the same horizontal line as the center of the photocathode of the photodetector. The optical fiber bundle is used to couple the near-infrared scintillation light pulses and transmit them to the photodetector.

[0012] The photoelectric detector is a near-infrared photoelectric detector, which is used to convert near-infrared scintillation light pulses into electrical pulses to achieve pulse radiation detection.

[0013] Furthermore, optical fiber connectors are provided at both ends of the optical fiber bundle; the input end of the optical fiber bundle and the near-infrared scintillator are fixed by the same fixing member; the fixing member is a cylindrical structure, one end of which is fixedly connected to the near-infrared scintillator, and the other end is fixedly connected to the optical fiber connector at the input end of the optical fiber bundle through a flange, so that the input end of the optical fiber bundle and the light-emitting surface of the near-infrared scintillator are in contact with each other within the cylindrical structure;

[0014] The output end of the optical fiber bundle is connected to the photodetector via a connector; the connector is a cylindrical structure, one end of which is movably connected to the optical fiber connector at the output end of the optical fiber bundle along the axial direction, and the other end is fixedly connected to the photodetector.

[0015] Furthermore, the distance l between the output end of the optical fiber bundle and the photocathode of the photodetector must satisfy:

[0016]

[0017] Where D is the diameter of the photocathode of the photodetector; d is the diameter of the cross section of the optical fiber bundle; and θ is the divergence angle of the light emitted from the optical fiber bundle.

[0018] Furthermore, a filter is provided between the output end of the optical fiber bundle and the photocathode of the photodetector, and the diameter of the filter is 25.4 mm to 50.8 mm.

[0019] Furthermore, the light-emitting surface of the near-infrared scintillator is polished or roughened, and the roughening treatment helps to improve the light emission efficiency; the scintillation wavelength of the light-emitting surface of the near-infrared scintillator is 800nm ​​to 2000nm;

[0020] The thickness of the near-infrared scintillator is 0.3 mm to 5 mm.

[0021] Furthermore, the length of the optical fiber bundle is 40 to 600 m, and the outer side of the optical fiber bundle is covered with a sleeve.

[0022] Furthermore, the single-mode optical fiber or the multi-mode optical fiber includes a core and a reflective layer coated outside the core.

[0023] Furthermore, the spectral response range of the photocathode of the photodetector is 780 to 2000 nm;

[0024] The diameter of the photosensitive surface of the photodetector is 9 to 50 mm.

[0025] At the same time, the present invention also provides a near-infrared scintillator-based pulse radiation detection system, comprising a pulse ray source, a digital oscilloscope, and the above-mentioned near-infrared scintillator-based pulse radiation detection device;

[0026] The pulse ray source is arranged close to the incident surface of the near-infrared scintillator and is used to emit pulse radiation;

[0027] The digital oscilloscope is connected to the photoelectric detector and is used for receiving the electric pulses transmitted by the photoelectric detector and recording the waveforms of the electric pulses.

[0028] Furthermore, it also includes a monitoring detector, which is set close to the pulse radiation source and connected to the digital oscilloscope to obtain the waveform of the pulse radiation and monitor the electrical pulse waveform recorded by the digital oscilloscope.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. The present invention provides a near-infrared scintillator-based pulsed radiation detection device, comprising a near-infrared scintillator, an optical fiber bundle, and a photodetector. The near-infrared scintillator receives pulsed radiation and emits near-infrared scintillation light pulses. The optical fiber bundle couples the near-infrared scintillation light pulses and transmits them to the photodetector. The photodetector converts the near-infrared scintillation light pulses into electrical pulses, thereby enabling pulsed radiation detection. The present invention efficiently couples near-infrared scintillation light into the optical fiber bundle and transmits it with low attenuation and high time resolution. This device can be used not only as a pulsed radiation measurement and detection device, but also for studying the scintillation characteristics of near-infrared scintillators.

[0031] 2. In the pulse radiation detection device based on near-infrared scintillator provided by the present invention, an optical fiber bundle is used to efficiently collect and transmit pulse scintillation light to a longer distance, thereby solving the problem of interference of the ray beam on the high-sensitivity photoelectric detector.

[0032] 3. In the pulse radiation detection device based on near-infrared scintillator provided by the present invention, the optical fiber bundle is composed of several single-mode optical fibers or multi-mode optical fibers of equal length and independent of each other glued together in parallel, which not only maintains the same time resolution as a single optical fiber, but also expands the light receiving area and has high sensitivity, overcoming the problem of low luminous efficiency and low signal-to-noise ratio of near-infrared scintillating materials.

[0033] 4. In the pulse radiation detection device based on near-infrared scintillator provided by the present invention, fixing parts and connecting parts are used to connect the near-infrared scintillator, optical fiber bundle and photoelectric detector into one, thereby ensuring the stability and accuracy of detection.

[0034] 5. In the pulse radiation detection device based on near-infrared scintillator provided by the present invention, the distance between the output end of the optical fiber bundle and the photocathode of the photodetector must meet corresponding requirements, thereby effectively reducing the light power density on the photocathode surface, ultimately suppressing the nonlinear effect of the photodetector and improving the detection accuracy.

[0035] 6. The pulse radiation detection system based on near-infrared scintillators provided by the present invention can not only use fast-decaying scintillating materials as pulse radiation detection devices, but also study and compare the pulse response characteristics of various near-infrared scintillating materials under ray pulses. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic structural diagram of an embodiment of a pulse radiation detection device based on a near-infrared scintillator according to the present invention.

[0037] Figure 2 This is a graph showing the input pulse spectrum of the optical fiber bundle in an embodiment of the pulse radiation detection device based on near-infrared scintillator of the present invention.

[0038] Figure 3This is a comparison diagram of the pulse broadening of a single optical fiber and a fiber bundle in an embodiment of the pulse radiation detection device based on near-infrared scintillator of the present invention.

[0039] Figure 4 Schematic diagram of the structure of an embodiment of a pulse radiation detection system based on near-infrared scintillator according to the present invention.

[0040] Figure 5 This is a comparison diagram of the gallium arsenide signal and the monitoring detector signal in an embodiment of the pulse radiation detection system based on near-infrared scintillator of the present invention.

[0041] The reference numerals are as follows:

[0042] 1-Near-infrared scintillator, 2-Fiber optic bundle, 3-Photodetector, 4-Pulse ray source, 5-Digital oscilloscope, 6-Monitoring detector. DETAILED DESCRIPTION

[0043] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are not intended to limit the present invention.

[0044] like Figure 1 As shown, this embodiment provides a pulse radiation detection device based on a near-infrared scintillator, including a near-infrared scintillator 1, an optical fiber bundle 2 and a photodetector 3.

[0045] The near-infrared scintillator 1 is a thin sheet-like structure with one side as the incident surface for receiving pulsed radiation and the other side as the light-emitting surface for emitting near-infrared scintillation light pulses. The thickness of the near-infrared scintillator 1 is less than its absorption length for the scintillation light, typically ranging from 0.3mm to 5mm. The near-infrared scintillator 1 can be made of crystals such as gallium arsenide and indium phosphide, with any doping type, and can also be made of other near-infrared scintillating materials.

[0046] The near-infrared scintillator 1 of this embodiment uses an undoped gallium arsenide wafer with a thickness of 350 microns and a diameter of 50.8 mm. At the same time, its light-emitting surface is polished, and the scintillation wavelength of the light-emitting surface is 800 nm to 2000 nm.

[0047] Fiber bundle 2 is composed of several independent, parallel-bonded single-mode or multimode optical fibers of equal length. The number of fiber bundles 2 can reach approximately one thousand or even more, increasing the efficiency of scintillation light coupling. Each optical fiber comprises a core and a reflective coating surrounding the core. This allows for separate transmission of light within the fiber, minimizing crosstalk and maintaining the same temporal resolution as a single optical fiber. Each optical fiber within bundle 2 can be either single-mode or multimode. Multimode fibers can achieve transmission distances up to 200 meters with a bandwidth in the GHz range. Single-mode fibers can achieve even longer transmission distances with the same bandwidth. The input and output ends of bundle 2 have a cross-sectional diameter of no less than 3 mm, with the fibers closely packed and their end faces smooth. The bundle can be 40 to 600 meters long, significantly increasing the detection distance while maintaining good detection accuracy. In this embodiment, bundle 2 is composed of multiple closely packed multimode optical fibers, is 40 meters long, and has a cross-sectional diameter of 3.5 mm at the light input end. The input end of bundle 2 is parallel and closely coupled to the polished surface of gallium arsenide. At the same time, the outer side of the optical fiber bundle 2 is covered and constrained with a plastic sleeve to avoid the use of metal materials and reduce the radiation-related effects.

[0048] The input end of the fiber bundle 2 is aligned with the light-emitting surface of the near-infrared scintillator 1 and is smaller in area than the light-emitting surface of the near-infrared scintillator 1, thereby improving light coupling efficiency. Coupling oil can also be applied to the input end of the fiber bundle 2 and the light-emitting surface of the near-infrared scintillator 1 to further reduce interfacial reflection and improve coupling efficiency.

[0049] The output end of fiber bundle 2 is coupled to photodetector 3, with the center of the output end and the center of the photocathode of photodetector 3 aligned horizontally. Fiber bundle 2 couples near-infrared scintillation light pulses and transmits them to photodetector 3. The output light from fiber bundle 2 travels a distance in free space before entering the photocathode of near-infrared photodetector 3, effectively reducing the optical power density on the photocathode surface and thereby suppressing the nonlinear effects of photodetector 3.

[0050] The photodetector 3 is a near-infrared photodetector used to convert near-infrared scintillation light pulses into electrical pulses to detect pulsed radiation. The distance l between the output end of the optical fiber bundle 2 and the photocathode of the photodetector 3 must satisfy the following requirements:

[0051]

[0052] Wherein, D is the diameter of the photocathode of the photodetector 3; d is the diameter of the cross section of the optical fiber bundle 2; and θ is the divergence angle of the light emitted from the optical fiber bundle 2.

[0053] The specific installation method of the pulse radiation detection device based on the near-infrared scintillator in this embodiment is that optical fiber connectors are respectively provided at both ends of the optical fiber bundle 2. FC connectors, SMA connectors, etc. can be selected. If the cross-sectional diameter of the input and output ends of the optical fiber bundle 2 is greater than 1 mm, it can also be made into a cylindrical shape. The input end of the optical fiber bundle 2 is fixed to the near-infrared scintillator 1 through the same fixing part; the fixing part is a cylindrical structure and has a light-shielding function to prevent external stray light from entering the input end of the optical fiber bundle 2. One end of the fixing part is fixedly connected to the near-infrared scintillator 1; the other end is fixedly connected to the optical fiber connector at the input end of the optical fiber bundle 2 through a flange, so that the input end of the optical fiber bundle 2 and the light-emitting surface of the near-infrared scintillator 1 fit together in the cylindrical structure.

[0054] The output end of the fiber bundle 2 is connected to the photodetector 3 via a connector. This cylindrical connector has one end axially flexibly connected to the fiber connector at the output end of the fiber bundle 2 and the other end fixedly connected to the photodetector 3. This connector not only adjusts the installation distance between the output end of the fiber bundle 2 and the photocathode of the photodetector 3, but also provides good light shielding between the output end of the fiber bundle 2 and the receiving end of the photodetector 3, thereby preventing ambient stray light from entering the photodetector 3. After installation, ensure that the center of the output end of the fiber bundle 2 and the center of the photocathode of the photodetector 3 are aligned horizontally.

[0055] In this embodiment, a filter is further provided between the output end of the optical fiber bundle 2 and the photocathode of the photodetector 3. The diameter of the filter is 25.4mm to 50.8mm. The filter is used to select light of a specific wavelength range to enter the photodetector 3, thereby improving detection efficiency and detection accuracy.

[0056] In this embodiment, the spectral response range of the photocathode of the photodetector 3 is 780 nm to 2000 nm; the diameter of the photosensitive surface of the photodetector 3 is 9 mm to 50 mm.

[0057] The light transmission performance test comparison of the optical fiber bundle 2 in this embodiment is as follows: Figure 2 、 Figure 3 As shown, Figure 2 This is the input pulse spectrum diagram when testing fiber bundle 2. Figure 3 This is a waveform comparison of the same incident pulse after passing through a 1-meter-long single-mode optical fiber and a 40-meter-long optical fiber bundle. It can be seen that for near-infrared light, pulse broadening can be ignored.

[0058] The pulse radiation detection device based on near-infrared scintillator provided by the present invention can efficiently couple near-infrared scintillation light into an optical fiber bundle and transmit it with low attenuation and high time resolution. It can not only be used as a pulse radiation measurement and detection device, but also can be used to study the scintillation characteristics of near-infrared scintillation materials.

[0059] like Figure 4As shown, this embodiment also provides a near-infrared scintillator-based pulse radiation detection system, comprising a pulsed radiation source 4, a digital oscilloscope 5, and a near-infrared scintillator-based pulsed radiation detection device. The pulsed radiation source 4 is positioned near the incident surface of the near-infrared scintillator 1 and is configured to emit pulsed radiation. This embodiment utilizes a pulsed X-ray source with a maximum voltage of 450 kV and a pulse width of approximately 20 ns. The digital oscilloscope 5 is connected to the photodetector 3 to receive the electrical pulses transmitted by the photodetector 3 and record the waveform of the electrical pulses.

[0060] The near-infrared scintillator 1 of this embodiment emits near-infrared scintillation light pulses after receiving pulse radiation. The optical fiber bundle 2 couples the near-infrared scintillation light pulses and transmits them to the near-infrared photodetector. The near-infrared photodetector converts the near-infrared scintillation light pulses into electrical pulses and transmits them to the digital oscilloscope 5. The digital oscilloscope 5 records the waveform of the electrical pulses, thereby realizing the measurement of the pulse radiation.

[0061] To improve detection accuracy, this embodiment further includes a monitoring detector 6, which is connected to the digital oscilloscope 5 and is used to monitor the waveform of the electrical pulse recorded by the digital oscilloscope 5. The monitoring detector 6 is a photomultiplier tube and is placed close to the pulse X-ray source. When the pulse X-ray is emitted, it obtains the waveform of the pulse radiation and compares it with the waveform of the electrical pulse recorded by the digital oscilloscope 5.

[0062] Figure 5 The comparison diagram of the electric pulse waveform recorded by the digital oscilloscope 5 and the waveform of the pulse radiation obtained by the monitoring detector 6 is shown. The two waveforms are roughly the same, and the electric pulse waveform recorded by the digital oscilloscope 5 (i.e. Figure 5 The width of the single-side polished GaAs signal in the image is slightly narrower, indicating higher temporal resolution.

[0063] The detection system of this embodiment can perform pulse radiation detection at room temperature, and can efficiently couple near-infrared light into the optical fiber bundle 2 and transmit it with low attenuation and low broadening.

[0064] The above descriptions are merely embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent structural transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied to other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A pulse radiation detection device based on a near-infrared scintillator, characterized by: It comprises a near-infrared scintillator (1), an optical fiber bundle (2) and a photodetector (3); The near-infrared scintillator (1) is a thin sheet structure, one side of which is an incident surface for receiving pulse radiation, and the other side is a light-emitting surface for emitting near-infrared scintillation light pulses; The optical fiber bundle (2) is formed by gluing together a plurality of single-mode optical fibers or multi-mode optical fibers of equal length and independent of each other; the input end of the optical fiber bundle (2) is in contact with the light-emitting surface of the near-infrared scintillator (1), and the area thereof is smaller than the area of ​​the light-emitting surface of the near-infrared scintillator (1); the output end of the optical fiber bundle (2) is connected to the photodetector (3), and the center of the output end and the center of the photocathode of the photodetector (3) are located on the same horizontal line; the optical fiber bundle (2) is used to couple the near-infrared scintillation light pulse and transmit it to the photodetector (3); The photoelectric detector (3) is a near-infrared photoelectric detector, which is used to convert near-infrared scintillation light pulses into electrical pulses to achieve pulse radiation detection.

2. The near-infrared scintillator-based pulse radiation detection device according to claim 1, characterized in that: Optical fiber connectors are respectively provided at both ends of the optical fiber bundle (2); the input end of the optical fiber bundle (2) and the near-infrared scintillator (1) are fixed via the same fixing member; the fixing member is a cylindrical structure, one end of which is fixedly connected to the near-infrared scintillator (1), and the other end of which is fixedly connected to the optical fiber connector at the input end of the optical fiber bundle (2) via a flange, so that the input end of the optical fiber bundle (2) and the light-emitting surface of the near-infrared scintillator (1) are fitted within the cylindrical structure; The output end of the optical fiber bundle (2) is connected to the photodetector (3) via a connector; the connector is a cylindrical structure, one end of which is movably connected to the optical fiber connector at the output end of the optical fiber bundle (2) along the axial direction, and the other end of which is fixedly connected to the photodetector (3).

3. The near-infrared scintillator-based pulse radiation detection device according to claim 2, characterized in that: The distance l between the output end of the optical fiber bundle (2) and the photocathode of the photodetector (3) must satisfy: Wherein, D is the diameter of the photocathode of the photodetector (3); d is the diameter of the cross section of the optical fiber bundle (2); and θ is the divergence angle of the light emitted from the optical fiber bundle (2).

4. The near-infrared scintillator-based pulse radiation detection device according to claim 3, characterized in that: A filter is provided between the output end of the optical fiber bundle (2) and the photocathode of the photodetector (3), and the diameter of the filter is 25.4 mm to 50.8 mm.

5. The near-infrared scintillator-based pulse radiation detection device according to any one of claims 1 to 4, characterized in that: The light-emitting surface of the near-infrared scintillator (1) is polished or roughened, and the scintillation wavelength of the light-emitting surface is 800nm ​​to 2000nm; The thickness of the near-infrared scintillator (1) is 0.3 mm to 5 mm.

6. The near-infrared scintillator-based pulse radiation detection device according to claim 5, characterized in that: The length of the optical fiber bundle (2) is 40 to 600 m, and the outer side of the optical fiber bundle (2) is covered with a sleeve.

7. The pulse radiation detection device based on near-infrared scintillator according to claim 1, characterized in that: The single-mode optical fiber or multi-mode optical fiber includes a core and a reflective layer covering the core.

8. The near-infrared scintillator-based pulse radiation detection device according to claim 7, characterized in that: The spectral response range of the photocathode of the photodetector (3) is 780-2000 nm; The diameter of the photosensitive surface of the photodetector (3) is 9 to 50 mm.

9. A pulse radiation detection system based on near-infrared scintillator, characterized by: It comprises a pulsed ray source (4), a digital oscilloscope (5), and a near-infrared scintillator-based pulsed radiation detection device according to any one of claims 1 to 8; The pulse ray source (4) is arranged close to the incident surface of the near-infrared scintillator (1) and is used to emit pulse radiation; The digital oscilloscope (5) is connected to the photoelectric detector (3) and is used for receiving the electric pulses transmitted by the photoelectric detector (3) and recording the waveforms of the electric pulses.

10. The near-infrared scintillator-based pulse radiation detection system according to claim 9, characterized in that: It also includes a monitoring detector (6), which is arranged close to the pulse ray source (4) and connected to the digital oscilloscope (5) for obtaining the waveform of the pulse radiation and monitoring the electrical pulse waveform recorded by the digital oscilloscope (5).

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