Scintillation detection system

Abstract

The invention relates to a scintillation detection system, which belongs to the technical field of X-ray signal detection, solves the technical problems of weak anti-interference capability and low signal-to-noise ratio of X-ray detection, and consists of a plurality of detection units which are serially arranged, each detection unit comprises an incident channel, a transmission channel, a reflection channel, a light collection channel, a scintillator, a scintillator support, an optical fiber light transmission beam, a photoelectric detector and an electromagnetic shielding box. The incident channel, the transmission channel, the reflection channel and the light collection channel are connected with one another to form a vacuum chamber. The center of the scintillator is located on a convergent point of central axes of the four channels. The surface of the scintillator is perpendicular to the central axis of the light collection channel. The incident end of the optical fiber light transmission beam is connected with the light collection channel, and the emergent end is connected with the photoelectric detector which is located in the electromagnetic shielding box. Light emitted by the scintillator reaches the incident end surface of the optical fiber light transmission beam, and the light intensity is uniformly distributed. The low-intensity X-ray detector is used for low-intensity X-ray detection under strong background interference.

Description

Technical Field

[0001] This invention belongs to the field of X-ray signal detection technology, specifically relating to a scintillation detection system. Background Technology

[0002] The working principle of a scintillation detection system is to use a scintillator as the conversion medium. When a particle enters the scintillator, the energy deposited within it is converted into visible light and emitted outwards. The intensity of the emitted light is measured by a photodetector, thus measuring the radiation intensity. Because scintillators can respond to almost all types of incident particles by producing visible light, scintillation detection systems are widely used in various particle detection applications and radiation flow parameter diagnosis. In the field of X-ray detection, scintillators have been one of the mainstream X-ray detection methods from the beginning due to their strong response to X-rays. However, since scintillators can produce visible light for almost all types of incident particles, scintillation detection systems often require various particle discrimination techniques when measuring specific particles in a mixed radiation flow. For X-rays, it is difficult to identify and separate their signals using particle discrimination methods. Furthermore, for some large X-ray generating devices, the output radiation flow contains high-intensity visible light, which can strongly interfere with the photodetector in the scintillation detection system. Therefore, how to use scintillation detection systems to measure X-rays in mixed radiation flows has always been challenging.

[0003] Jiang Shilun, Ning Jiamin, Xu Rongkun, et al. disclosed a scintillation detection system structural design, see Z-pinch X-ray Radiation Power Scintillation Detection System [J], Atomic Energy Science and Technology, 2006, 40(1):96-99. This system employs a scintillator arrangement at a 45-degree angle to the X-ray incident direction and a detector setup where the sensitive surface is parallel to the scintillator plane to measure Z-pinch pulsed X-rays. A background detector is placed at the end of the X-ray transmission direction to directly measure the X-ray signal transmitted through the scintillator. This structure effectively reduces the influence of visible light.

[0004] Zhang Siqun, Huang Xianbin, Li Jing, et al. disclosed a scintillation power meter for measuring X-ray yield in Z-pinch plasma [J], High Power Laser and Particle Beams, 2010, 22(4):880-882. They discussed two scintillation detection system designs, both employing a scintillator arranged at a 45-degree angle to the X-ray incident direction. Detectors were positioned at the radiation incident and transmission surfaces of the scintillator at 90-degree angles to the X-ray transmission direction to measure X-ray radiation power. However, this design is primarily intended for applications with relatively simple radiation beams, such as synchrotron radiation, where radiation interference is naturally low. The influence of other radiation components in the mixed radiation stream on the measurement is not fully considered during the measurement process, resulting in significant limitations in the measurement of X-ray intensity in mixed-field applications.

[0005] Zhang Mei, Peng Bodong, Sheng Liang, et al. published a study on the relative sensitivity of γ-ray scintillator-fiber combined radiation detector [J], Nuclear Technology, 2009, 22(11):867-871. This paper studies the scintillator-fiber combined detector and its performance such as relative sensitivity, but does not carry out research on the separation and processing methods of background interference or structural design. Summary of the Invention

[0006] To overcome the shortcomings of weak anti-interference capability and low signal-to-noise ratio in X-ray detection, this invention proposes a scintillation detection system.

[0007] The technical solution adopted by this invention to solve its technical problem is: A scintillation detection system consists of several detection units arranged in series. Each detection unit includes an incident channel, a transmission channel, a reflection channel, a light collection channel, a scintillator, a scintillator support, an optical fiber beam transmitter, a photodetector, and an electromagnetic shielding box.

[0008] The incident channel, transmission channel, reflection channel, and light collection channel are interconnected, forming a vacuum chamber. The central axes of the four channels are coplanar. The transmission channel coincides with the central axis of the incident channel and has the same inner diameter. The reflection channel is perpendicular to the incident channel and the transmission channel. The light collection channel is at a 45-degree angle to the transmission channel.

[0009] The front end of the incident channel is connected to the end of the transmission channel of the X-ray source or the pre-detection unit via a flange.

[0010] The end of the transmission channel is connected to the front end of the incident channel or the blind plate of the subsequent detection unit via a flange.

[0011] The scintillator and its support are located within a vacuum chamber, with the center of the scintillator situated at the convergence point of the central axes of the four channels. The surface of the scintillator is perpendicular to the central axis of the light-collecting channel, and is used to convert radiation entering through the incident channel into visible light.

[0012] The scintillator support is fixedly connected to the flange at the end of the transmission channel to fix the scintillator.

[0013] The blind plate at the end of the transmission channel is used to absorb visible light transmitted by the scintillator.

[0014] A blind plate is installed at the end of the reflection channel. The blind plate at the end of the reflection channel is connected to the end of the reflection channel via a flange and is used to absorb visible light reflected by the scintillator.

[0015] The optical fiber beam's input end is connected to a light-collecting channel, and its output end is connected to a photodetector. The photodetector collects the visible light emitted by the scintillator and transmits it to the photodetector. The photodetector then converts the visible light output from the optical fiber beam into an electrical signal.

[0016] The scintillator emits light that reaches the incident end of the optical fiber beam, resulting in a uniform distribution of light intensity.

[0017] The photodetector is located in an electromagnetic shielding box, which is used for electromagnetic shielding of the photodetector.

[0018] In the aforementioned scintillation detection system, the incident channel and transmission channel are placed horizontally, the reflection channel is placed vertically, the vacuum chamber is cylindrical in the horizontal direction, and the inner wall of the vacuum chamber is sandblasted.

[0019] In the aforementioned scintillation detection system, the flange is a vacuum-sealed flange, and the blind plate is entirely blackened.

[0020] In the aforementioned scintillation detection system, the incident end of the optical fiber beam is connected to the end of the light collection channel via a flange, and the connection between the light collection channel and the optical fiber beam is vacuum-sealed using ultraviolet quartz glass.

[0021] In the aforementioned scintillation detection system, the scintillator is an ultra-thin scintillator with a coated finish and an X-ray transmittance of less than 1E-4. More than 99% of the visible light in the radiation stream incident on the scintillator enters both the transmission and reflection channels.

[0022] The aforementioned scintillation detection system includes a cylindrical wall and a pressure ring in the scintillator support.

[0023] The cylinder wall has a cylindrical hollow structure, with the front end face forming a 45° angle with the central axis of the transmission channel 2, and the end face fixedly connected to the flange at the end of the transmission channel 2.

[0024] The blind plate at the end of transmission channel 2 is blackened and thinned.

[0025] The scintillator is located between the cylinder wall and the pressure ring. The front end of the cylinder wall is in contact with the bottom surface of the scintillator, and the pressure ring is in contact with the surface of the scintillator.

[0026] In the aforementioned scintillation detection system, the optical fiber beam is a split-beam structure.

[0027] The optical fiber beam is split at the output end.

[0028] The optical fiber beam is aggregated using radiation-resistant quartz optical fiber, and the optical fibers are evenly bundled and arranged.

[0029] In the aforementioned scintillation detection system, the photodetector is a high-gain photomultiplier tube.

[0030] The aforementioned scintillation detection system features an electromagnetic shielding box that is a double-layered insulated metal enclosure with full welding, achieving an electromagnetic shielding level better than 70dB. A cable interface is provided, densely filled with metal wool.

[0031] In the aforementioned scintillation detection system, the detection unit comprises two or more units.

[0032] The beneficial effects of this invention are: A scintillation detection system has a four-channel measurement unit and a scintillator arranged at a 45-degree angle. After the radiation flow enters the measurement unit, visible light mainly enters the transmission channel and the reflection channel in the form of transmission and 90-degree angle reflection, reducing the visible light entering the light collection channel to less than 1%. Combined with the blackening of the channel end and the sandblasting process of the inner wall, the probability of visible light entering the light collection channel through reflection or scattering of the inner wall of the cavity is further greatly reduced, effectively reducing the influence of visible light in the mixed radiation flow on the measurement.

[0033] A scintillation detection system guides the light emitted by a scintillator into a photomultiplier tube protected by an electromagnetic shielding box through a beam transmission. While ensuring that the detector has high gain for the scintillator's light emission, it greatly reduces the impact of electromagnetic radiation on the photomultiplier tube and significantly expands the measurement lower limit.

[0034] A scintillation detection system is provided, wherein the central axis of the light collection channel is perpendicular to the surface of the scintillator, and the length of the light collection channel is designed according to the diameter of the incident radiation flow, the size of the incident end of the fiber optic beam, and the numerical aperture. The interface between the photomultiplier tube and the fiber optic beam is designed according to the size of the photocathode sensitive surface of the photomultiplier tube, the size of the incident end of the fiber optic beam, and the numerical aperture, so as to ensure the maximization of the scintillation light collection efficiency.

[0035] A scintillation detection system is provided in which the thickness of the scintillator is selected according to the X-ray energy to be measured, so as to ensure that the X-ray energy to be measured is completely deposited in the scintillator while minimizing the energy deposition of other radiation components in the radiation flow in the scintillator, thereby maximizing the proportion of the component generated by the deposition of the X-ray energy to be measured in the scintillator emission.

[0036] A scintillation detection system employs a tandem structure to simultaneously measure the intensity of X-rays in the incident radiation stream and the intensity information of other components. Furthermore, it eliminates the influence of non-X-ray components in the radiation stream on the measured X-ray intensity signal, significantly improving the accuracy of X-ray measurement results. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the detection unit structure according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the scintillator support structure according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the serial structure of the detection unit in Embodiment 1 of the present invention.

[0038] Figure label: 1. Incident channel, 2. Transmission channel, 3. Reflection channel, 4. Light collection channel, 5. Scintillator, 6. Scintillator support, 7. Fiber optic beam transmission, 8. Photodetector, 9. Electromagnetic shielding box, 10. Flange, 11. Blind flange; 61. Cylinder wall; 62. Support pressure ring. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0040] A scintillation detection system employs reusable structural units. Each unit includes a vacuum chamber comprising an incident channel, a transmission channel, a reflection channel, and a light collection channel; a scintillator; a scintillator support; an optical fiber beam transmitter; a photodetector; and an electromagnetic shielding box. The scintillator is mounted on the scintillator support and fixed to the center of the vacuum chamber via a flange. The incident end of the optical fiber beam transmitter is fixed to the end of the light collection channel, and the exit end is connected to the photodetector. The photodetector is installed inside the electromagnetic shielding box. This system is used for detecting low-intensity X-rays under strong background interference.

[0041] The incident channel, transmission channel, reflection channel, and light collection channel constitute a vacuum chamber, eliminating the need to consider intensity loss of X-rays during transport during measurement. The inner wall of the chamber is sandblasted, resulting in near-diffuse reflection of the radiation flow within the chamber, thus avoiding localized maxima of reflection intensity.

[0042] The transmission and reflection channels can form visible light trapping holes. Combined with the blackened blind plate at the end of the channel, a large amount of visible light entering the channel is absorbed. At the same time, by increasing the number of reflections, the probability of visible light entering the light collection channel through reflection is greatly reduced.

[0043] The inner diameter and length of the optical collection channel are determined by the beam diameter of the incident chamber and the size and numerical aperture of the incident end of the fiber optic beam, so that the light intensity of the scintillator light reaching the fiber optic beam is uniformly distributed on the surface of the incident end. The central axis of the optical collection channel is perpendicular to the surface of the scintillator. Since the light intensity of the scintillator is strongest in the direction perpendicular to the surface, it can ensure that as much scintillator light as possible enters the optical collection channel, thereby maximizing the light collection efficiency of the scintillator.

[0044] The scintillator is arranged at a 45-degree angle, so that more than 99% of the visible light in the radiation stream incident on the scintillator enters the transmission and reflection channels, greatly reducing the intensity of visible light entering the light collection channel after single scattering.

[0045] The thickness of the scintillator is set according to the energy range of the X-rays to be measured, so that the X-ray transmittance within the energy range is less than 1E-4, thereby maximizing the efficiency of X-ray conversion to visible light while reducing the detection efficiency of the scintillator for other radiation / particles.

[0046] Scintillators can be coated as needed. By adding a thin film of a specific material to the scintillator's radiative inrush surface, the energy response curve of the scintillator can be modulated, thereby optimizing the scintillation detection system for a specific energy range and improving its quantitative measurement capabilities.

[0047] The scintillator support adopts a hollowed-out sidewall structure to reduce air resistance and scattering of radiation flow, while avoiding obstruction of the scintillator's light emission into the light collection channel.

[0048] The fiber optic beam is aggregated using radiation-resistant silica fiber to reduce the intensity of its own radiation emission. The fiber is arranged using a uniform beam splitting method so that incident light in any region at the incident end can be transmitted to each beam at the output end in the same proportion.

[0049] The photodetector uses a high-gain photomultiplier tube, which has the ability to detect signals with extremely low intensity. The distance between the photodetector and the fiber optic beam interface is given by the beam splitting size, numerical aperture and cathode sensitive surface size of the fiber optic beam output end. This ensures that the visible light emitted from the fiber optic beam output end can be uniformly irradiated on the cathode sensitive surface of the photodetector, thereby maximizing the light collection efficiency of the detector and maximizing the utilization of the linear measurement capability of the photodetector.

[0050] As an independent structural unit, the scintillation detection system can be arranged in series. By customizing the scintillator and the unit structure, it is possible to quantitatively measure different components in the same incident radiation stream.

[0051] The electromagnetic shielding box adopts a double-layer insulated metal enclosure with full welding process to achieve electrical isolation between the inner and outer enclosures. All cable interfaces are densely filled with metal wool to achieve an electromagnetic shielding level of better than 70dB. Example 1

[0052] A scintillation detection system includes an incident channel 1, a transmission channel 2, a reflection channel 3, a light collection channel 4, a scintillator 5, a scintillator support 6, an optical fiber beam 7, a photodetector 8, and an electromagnetic shielding box 9. The four channels (incident channel 1, transmission channel 2, reflection channel 3, and light collection channel 4) form a vacuum chamber. A scintillator of appropriate thickness is selected based on the X-ray energy to be measured, and a suitable material is used to coat the scintillator. After processing, the scintillator 5 is mounted on the scintillator support 6 and fixed to the end of the transmission channel 2. At this point, the center of the scintillator is located at the intersection of the central axes of the four channels of the detection unit. A quartz glass vacuum seal is used at the end of the light collection channel 4, connecting it to the incident end of the beam 7. The exit end of the beam 7 passes through the electromagnetic shielding box 9 and connects to the photomultiplier tube 8 installed within it. After assembling the measurement units, several measurement units are connected in series to form a complete testing system. Connecting the front flange of the incident channel of the frontmost test unit of the testing system to the light source allows for the measurement of the X-ray intensity in the emitted radiation stream from the light source.

[0053] A four-channel tandem scintillation detection system employs, for example... Figure 3 The structural unit shown includes, in each unit, an incident channel 1, a transmission channel 2, a reflection channel 3, a light collection channel 4, a scintillator 5, a scintillator support 6, an optical fiber beam transmitter 7, a photodetector 8, and an electromagnetic shielding box 9. Figure 1 As shown.

[0054] The front end of the incident channel 1 is a vacuum-sealed flange, which can be connected to the X-ray source, the pre-vacuum pipeline, or a scintillation detection system of the same structure.

[0055] The transmission channel 2 is coaxial with the incident channel 1 and has the same inner diameter. Its end is a vacuum-sealed flange, which is connected to the end flange of the scintillator support 6 for fixing the scintillator support 6 in the channel.

[0056] The reflection channel 3 is perpendicular to the incident channel 1, and its end is a vacuum-sealed flange blind plate. The blind plate is blackened as a whole to absorb visible light and low-energy X-rays reflected by the scintillator.

[0057] The light collection channel 4 is at a 45-degree angle to the transmission channel 2, and its central axis is coplanar with the central axes of the incident channel 1, the transmission channel 2, and the reflection channel 3. The end of the channel is a vacuum-sealed flange, which is vacuum-sealed using ultraviolet quartz glass and connected to the incident end of the fiber optic beam 7.

[0058] The incident channel 1, transmission channel 2, reflection channel 3, and light collection channel 4 form a vacuum chamber. The central axes of all channels converge at the same point.

[0059] The scintillator 5 is an ultra-thin scintillator that converts the radiation entering the detection system from the incident channel 1 into visible light. The scintillator is fixed on the scintillator support 6, and the surface of the scintillator is perpendicular to the central axis of the light collection channel 4, with the center of the scintillator located at the convergence point of the central axes of all channels in the vacuum chamber.

[0060] The scintillator support 6 has a cylindrical wall 6-1 with a hollow structure, such as... Figure 2 As shown, the front end has a 45-degree bevel and is equipped with a pressure ring 6-2 for fixing the scintillator 5, while the rear end has a vacuum-sealed flange 10 connected to the transmission channel 2. In addition, the scintillator support is also equipped with an independent flange blind plate 11, which is blackened and thinned for sealing the vacuum chamber of the detection system. The rear flange of the scintillator support 6 can also be connected to the front flange of the incident channel 1 of a scintillation detection system with the same structure, forming a tandem structure.

[0061] The fiber optic beam 7 employs a beam-splitting structure, allowing for beam splitting at the output end as needed for testing. The input end of the beam is connected to the light collection channel, and the output end is connected to the photodetector 8, which collects the light emitted by the scintillator and transmits it to the photodetector.

[0062] The photodetector 8 uses a high-gain photomultiplier tube to convert the visible light output from the beam 7 into an electrical signal output. The photodetector is housed in an electromagnetic shielding box 9.

[0063] The electromagnetic shielding box 9 adopts a double-layer metal cavity with internal and external insulation and a full welding process to achieve electromagnetic shielding of the internal space and reduce the interference of the spatial electromagnetic field on the output of the photodetector.

Claims

1. A scintillation detection system, characterized in that, It consists of several detection units in series. Each detection unit includes an incident channel (1), a transmission channel (2), a reflection channel (3), a light collection channel (4), a scintillator (5), a scintillator support (6), an optical fiber beam transmission (7), a photodetector (8), and an electromagnetic shielding box (9). The incident channel (1), transmission channel (2), reflection channel (3), and light collection channel (4) are interconnected, forming a vacuum chamber. The central axes of the four channels are coplanar. The transmission channel (2) coincides with the central axis of the incident channel (1) and has the same inner diameter. The reflection channel (3) is perpendicular to the incident channel (1) and the transmission channel (2). The light collection channel (4) forms a 45-degree angle with the transmission channel (2). The front end of the incident channel (1) is connected to the end of the transmission channel (2) of the X-ray source or the pre-stage detection unit via a flange (10); The end of the transmission channel (2) is connected to the front end of the incident channel (1) of the subsequent detection unit or the blind plate (11) via a flange (10); The scintillator (5) and scintillator support (6) are located in the vacuum chamber. The center of the scintillator (5) is located at the convergence point of the central axes of the four channels. The surface of the scintillator (5) is perpendicular to the central axis of the light collection channel (4) and is used to convert the radiation entering through the incident channel (1) into visible light. The scintillator bracket (6) is fixedly connected to the flange (10) at the end of the transmission channel (2) for fixing the scintillator (5); The blind plate (11) at the end of the transmission channel (2) is used to absorb the visible light transmitted by the scintillator (5); A blind plate (11) is provided at the end of the reflection channel (3); the blind plate (11) at the end of the reflection channel (3) is connected to the end of the reflection channel (3) through a flange (10) to absorb the visible light reflected by the scintillator (5); The incident end of the fiber optic beam (7) is connected to the light collection channel (4), and the output end is connected to the photodetector (8) to collect the visible light emitted by the scintillator (5) and transmit it to the photodetector (8); the photodetector (8) is used to convert the visible light output by the fiber optic beam (7) into an electrical signal output. The scintillator (5) emits light that reaches the incident end surface of the fiber optic beam (7), and the light intensity is uniformly distributed. The photodetector (8) is located in the electromagnetic shielding box (9), which is used for electromagnetic shielding of the photodetector (8).

2. The scintillation detection system according to claim 1, characterized in that, The incident channel (1) and transmission channel (2) are placed horizontally, the reflection channel (3) is placed vertically, the vacuum chamber is cylindrical in the horizontal direction, and the inner wall of the vacuum chamber is sandblasted.

3. The scintillation detection system according to claim 1, characterized in that, The flange (10) is a vacuum-sealed flange, and the blind plate (11) is blackened as a whole.

4. The scintillation detection system according to claim 1, characterized in that, The incident end of the optical fiber beam (7) is connected to the end of the light collection channel (4) through a flange (10). The connection between the light collection channel (4) and the optical fiber beam (7) is vacuum sealed with ultraviolet quartz glass.

5. The scintillation detection system according to claim 1, characterized in that, The scintillator (5) is an ultrathin scintillator with a coating treatment and an X-ray transmittance of less than 1E-4; more than 99% of the visible light in the radiation stream incident on the scintillator (5) enters the transmission channel (2) and the reflection channel (3).

6. The scintillation detection system according to claim 1, characterized in that, The scintillator support (6) includes a cylindrical wall (61) and a pressure ring (62); The cylindrical wall (61) is a cylindrical hollow structure, with the front end face forming a 45° angle with the central axis of the transmission channel 2, and the end end fixedly connected to the flange (10) at the end of the transmission channel 2; The blind plate (11) at the end of the transmission channel 2 is blackened and thinned; The scintillator (5) is located between the cylinder wall (61) and the pressure ring (62). The front end of the cylinder wall (61) is in contact with the bottom surface of the scintillator (5), and the pressure ring (62) is in contact with the surface of the scintillator (5).

7. The scintillation detection system according to claim 1, characterized in that, The fiber optic beam (7) has a split beam structure; The optical fiber beam (7) is split at the output end; The optical fiber beam (7) is aggregated using radiation-resistant quartz optical fiber, and the optical fiber is evenly bundled and arranged.

8. The scintillation detection system according to claim 1, characterized in that, The photodetector (8) is a high-gain photomultiplier tube.

9. The scintillation detection system according to claim 1, characterized in that, The electromagnetic shielding box (9) is a double-layer insulated metal box with full welding process, and the electromagnetic shielding level is better than 70dB. A cable interface is provided, and the cable interface is densely filled with metal wool.

10. The scintillation detection system according to claim 1, characterized in that, The detection unit may consist of two or more units.

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