Continuous scintillator, preparation method thereof, detector and position detection method

Abstract

The invention discloses a continuous scintillator, a preparation method thereof, a detector and a position detection method. The continuous scintillator is characterized by comprising a transparent or semitransparent solvent, and a scintillator material with high light yield and low light attenuation length is uniformly mixed in the solvent. The detector comprises the continuous scintillator, optical fibers distributed in an array mode are arranged in the continuous scintillator, the two ends or one end of each optical fiber are located on the outer side of the continuous scintillator, and a detector is coupled to each optical fiber; during position detection, recording electric signal intensity information output by each detector, an optical fiber port corresponding to each detector and position information of each optical fiber; and calculating the incident position of the particle by adopting a gravity center method according to the recorded information. According to the invention, two characteristics of low attenuation length and high light yield are utilized, and the sensitivity of the scintillation light to the transmission distance is converted into the sensitivity of the position detection of the detector, so that the high-position-resolution detection of incident particles is realized.

Description

Technical Field

[0001] The invention belongs to the field of particle detection and ray imaging, and in particular relates to a continuous scintillator and a preparation method thereof, a detector and a position detection method. Background Art

[0002] Scintillator detectors are commonly used in the field of particle physics and nuclear physics. The principle of particle detection is that the incident particles emit scintillation light in the scintillator, and the scintillation light is transmitted to the photoelectric conversion device and converted into an electrical signal, so that the information of the incident particles is detected. Scintillator detectors have the advantages of stable performance, simple structure, no need for power supply for scintillators, can be made into various shapes, can be applied over a large area, and have low cost, and have a wide range of application scenarios.

[0003] Scintillator detectors are also widely used in particle position measurement. Usually, multiple scintillators are arranged into an array to achieve position detection. The position resolution that can be achieved by this detection method is determined by the size of the scintillator cross section. Large-area position resolution detectors require a large number of long strips of scintillators, but long strips of scintillators have processing difficulties such as difficult processing, large processing errors, and high defective product rates, and the achievable position resolution is limited. In view of the problems existing in the prior art, the present invention provides a new type of continuous scintillator with high light yield and low light attenuation length and a position detection method thereof. The present invention has the advantages of high position resolution, easy processing, and low cost. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a continuous scintillator and a preparation method thereof, a detector and a position detection method. Conventional scintillator detectors require that their light attenuation length is as large as possible, so that the scintillation light loss is small during the transmission of the optical signal and the detector performance is better. The present invention discloses a continuous scintillator with low light attenuation length and high light yield. The two characteristics of low attenuation length and high light yield are used to convert the sensitivity of scintillation light to transmission distance into the sensitivity of detector position detection, thereby realizing high position resolution detection of incident particles.

[0005] Some scintillator materials have high light yield but poor transmittance of scintillation light. Such materials are usually used in fluorescent screens, etc. For example, ZnS:Ag material can be used to detect α particles, etc. Its light yield is more than ten times that of ordinary liquid scintillators or plastic scintillators, but its light attenuation length is less than one tenth of that of ordinary liquid scintillators or plastic scintillators; 6 LiF / ZnS:Ag mixed materials have high neutron discrimination ability and also have the characteristics of high light yield and low light attenuation length. These high light yield materials cannot be directly used in position sensitive detectors because their light attenuation length is too low.

[0006] The scintillator material with high light yield and low light attenuation length is uniformly mixed in a transparent material to form a liquid or solid mixture. This mixture has the characteristics of high light yield and low light attenuation length, that is, a scintillator with high light yield and low light attenuation length. Particles incident on this scintillator can generate a large amount of scintillation light, but this scintillation light quickly decays and becomes smaller during light transmission. For ordinary detectors, a long light attenuation length is the characteristic that most detectors need more. However, the two characteristics of short light attenuation length combined with high light yield can be used to design the structure of the detector to form a new type of high position resolution detector. This detector has the advantages of stable structure, small size, simple support system, etc., and has a wide range of application characteristics.

[0007] The novel continuous scintillator with high light yield and low light attenuation length is made by uniformly mixing scintillator materials with high light yield and low light attenuation length in a solvent. The solvent can be a transparent or translucent material. The transmittance of the solvent is changed according to the detector's requirements for the scintillator attenuation length. The most suitable transmittance of the solvent needs to be obtained through simulation according to the position resolution target to be achieved by the detector, the concentration of the scintillator material, the optical fiber spacing and other parameters, and the reference transmittance parameters are obtained by simulation, and materials with different ratios are made with reference to these parameters. Experimental tests are performed on materials with different ratios to obtain the optimal solvent transmittance and other parameters. The solvent can also be a liquid or solid material. Different solvent materials are selected according to the application scenario of the detector. The scintillator material is uniformly mixed in the solvent and undergoes a physical or chemical process to generate a continuous scintillator with high light yield and low light attenuation length. Its form can be liquid, solid or liquid gel, etc. Different scintillator forms can be suitable for different detector requirements, and generally solid forms are more widely used.

[0008] The novel continuous scintillator with high light yield and low light attenuation length has two key characteristics: high light yield and low light attenuation length. Due to the characteristic of high light yield, the incident particles can generate a large amount of scintillation light in the scintillator, and the scintillation light is more easily detected by the photoelectric conversion device. Due to the characteristic of low light attenuation length of the scintillator, the scintillation light is attenuated faster on the light transmission path in the scintillator, so the scintillation light is sensitive to the transmission distance. The incident position of the particle can be calculated by mathematical calculation by detecting the light intensity at different positions. This process converts the sensitivity of the scintillator to the transmission distance of the scintillation light into the sensitivity of detecting the incident position of the particle, thereby realizing a detector with high position resolution.

[0009] The high position resolution detection method described above obtains the position of the incident particle through mathematical calculation, so that the position resolution of the detector is higher. This calculation method can be used in many ways, one of which is the centroid method. Figure 1The detector structure diagram shown in the figure shows that the process of calculating the position by the center of gravity method is as follows: in a row of optical fibers on the same horizontal plane, the two optical fibers with the largest light intensity are determined. The light intensity measured by one optical fiber is A1, and the position of this optical fiber is x1. The light intensity measured by the other optical fiber is A2, and the position of this optical fiber is x2. Then the incident position of the particle is:

[0010]

[0011] Through this detection and calculation process, a row of light can obtain one-dimensional position information of the incident particle. If multiple rows of optical fibers are arranged in different directions, multi-dimensional position information can be obtained.

[0012] The incident position can also be calculated using the light intensity information of multiple optical fibers near the incident position, which will have a higher accuracy. The above-mentioned centroid method assumes that the relationship between light intensity and distance is linear attenuation, which is a simplified method. The light attenuation curve of the scintillator, that is, the light intensity-distance relationship curve, is pre-tested through experiments. Applying the light attenuation curve to the calculation of the position can further improve the position resolution of the detector.

[0013] The high position resolution detector method is realized by structurally designing the novel continuous scintillator with high light yield and low light attenuation length of the present invention. Based on the above-mentioned high-resolution position detection method, various designs can be made according to the application requirements of the detector. Preliminary structural parameters can be obtained by simulating detectors of different structures, and then a detector design with better performance can be obtained through further experimental tests. Figure 1 and Figure 2 What is shown is a simple and universal detector structure design diagram. The scintillator in the figure is a planar scintillator, and two rows of optical fibers are arranged inside the scintillator. Particles are incident on the scintillator to generate scintillation light, which is transmitted and attenuated in the scintillator. When the scintillation light is transmitted to the side wall of the optical fiber, it enters the optical fiber. The light can use scintillation optical fiber. After the light in the optical fiber is transmitted to the end face of the optical fiber, it is converted into an electrical signal by the photoelectric conversion device (such as SiPM) coupled to the optical fiber. The electrical signal is processed by the back-end electronics to obtain the signal amplitude value. After the signal amplitude value is obtained, the position information can be calculated through the aforementioned mathematical calculation. Figure 1 In the structure, the two rows of optical fibers are perpendicular to each other. One row of optical fibers is used to test the position information in the x direction, and the other row of optical fibers is used to test the position information in the y direction. Therefore, such a detector can detect the (x, y) coordinates of the particle incident on this plane, that is, it tests the position information in two dimensions. If multiple groups of such detectors are placed along the z direction, the three-dimensional information (x, y, z) of multiple z positions can be detected, and the trajectory curve of the incident particle can be obtained.

[0014] In the detector method with high position resolution, the shape of the scintillator can be flexibly designed according to the application requirements of the detector, and the scintillator can be cylindrical, flat, etc.; optical fibers are arranged inside the scintillator, and the arrangement of the optical fibers can also be specifically arranged according to the needs of the detector; a schematic diagram of a detector with a cylindrical structure is shown in FIG. Figure 3 As shown in the figure, the straight fiber and the circular fiber each test the position information of one dimension. This structure can be applied to the detection of information such as the position of particles emitted from the barrel. If three rows of optical fibers in three directions are arranged in the scintillator, a detector can be used to detect the three-dimensional position information (x, y, z) of the incident particles. Figure 4 As shown, three rows of optical fibers are arranged inside a cube, a cuboid or a cylinder. The directions of the three rows of optical fibers are perpendicular to each other and are used to test the position information in the x, y and z directions. A detector can be used to realize the three-dimensional position information of the incident particle along its trajectory, and the trajectory and trajectory coordinates of the incident particle can be obtained.

[0015] Optical fibers are arranged in this new type of scintillator, and the optical fibers transmit the scintillation light at different positions of the scintillator to the photoelectric conversion device, so as to detect the scintillation light intensity at different positions. The incident position of the particle is calculated by mathematically calculating the light intensity of the optical fiber at different positions. When the particle is incident into the detector, scintillation light is generated. If it is a conventional scintillator with high light transmittance, the scintillation light will decay very slowly and can be transmitted over a long distance. In addition, the reflection and scattering of the scintillation light on the interface will cause great interference to the position detection. The difference in the light intensity signal received by the optical fiber near the particle incident position is very small, making it difficult to calculate the position information of the incident particle. The position-resolving detector designed with a scintillator with high light yield and low light attenuation length in the present invention has the characteristic of low light attenuation length, so the scintillation light far away from the particle incident position decays rapidly, and the scintillation light intensity received by the optical fiber near the particle incident position is very different, so the accuracy of the position data calculated by light intensity is higher.

[0016] The technical solution of the present invention is:

[0017] A continuous scintillator is characterized by comprising a transparent or translucent solvent in which a scintillator material with high light yield and low light attenuation length is uniformly mixed.

[0018] Furthermore, the solvent is a liquid scintillator solvent, a liquid gel scintillator solvent or a solid scintillator solvent.

[0019] Furthermore, the scintillator material with high light yield and low light attenuation length is ZnS:Ag material.

[0020] Furthermore, the scintillator material with high light yield and low light attenuation length is ZnS:Ag and 6LiF mixed material; ZnS:Ag and 6 LiF is mixed in a ratio of 2:1 to 3:1 and then added into the polyethylene material and mixed evenly.

[0021] Furthermore, the transmittance of the solvent is determined according to the light attenuation length of the detector to the continuous scintillator.

[0022] A method for preparing a continuous scintillator comprises the following steps: mixing scintillator materials with high light yield and low light attenuation length, adding the materials into a transparent or translucent solvent and mixing them evenly to obtain a liquid or solid mixture as the continuous scintillator.

[0023] A high position resolution detector based on the continuous scintillator, characterized in that an array of optical fibers is arranged in the continuous scintillator, both ends or one end of each optical fiber is located outside the continuous scintillator and coupled to a detector; the continuous scintillator is used to generate scintillation light when particles are incident; the optical fiber is used to receive the scintillation light incident along the side wall of the optical fiber and transmit it to the detector; the detector is used to convert the received optical signal into an electrical signal.

[0024] Furthermore, the continuous scintillator is provided with a plurality of optical fibers arranged in parallel along a first direction and a plurality of optical fibers arranged in parallel along a second direction, and the first direction is perpendicular to the second direction; or the continuous scintillator is provided with a plurality of optical fibers arranged in parallel along a first direction, a plurality of optical fibers arranged in parallel along the second direction and a plurality of optical fibers arranged in parallel along a third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

[0025] Furthermore, the continuous scintillator is a flat structure, a barrel structure, a cubic structure, a rectangular parallelepiped structure or a cylindrical structure.

[0026] A position detection method based on the high position resolution detector, the steps comprising:

[0027] 1) Recording the electrical signal strength information output by each detector, the optical fiber port corresponding to each detector, and the position information of each optical fiber;

[0028] 2) Based on the information recorded in step 1), the incident position of the particle is calculated using the center of gravity method.

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

[0030] The present invention solves the difficult problems of scintillator processing difficulty and high cost in position resolution measurement of scintillator detectors. The scintillator provided by the present invention is a new design, which utilizes the two characteristics of high light yield and low light attenuation length to make the scintillator sensitive to the transmission distance of scintillation light. The detector structure is designed to convert the sensitivity of the scintillator to the transmission distance of scintillation light into sensitivity to the incident position of the particle, thereby achieving high position resolution performance. The detector described in the present invention has the advantages of high position resolution, large-area application, stable structure, low cost and easy application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the detector structure and position calculation of the present invention.

[0032] Figure 2 Schematic diagram of a planar detector for two-dimensional position detection.

[0033] Figure 3 Schematic diagram of the barrel-type detector structure.

[0034] Figure 4 Schematic diagram of the cube detector structure for three-dimensional position detection. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention but not to limit the scope of the present invention.

[0036] This embodiment is directed to two-dimensional position detection of neutrons and can be applied to neutron incident position detection, neutron track detection, neutron imaging, and the like.

[0037] ZnS:Ag and 6 LiF is mixed in a certain ratio (for example, 2:1 to 3:1) and then added to the polyethylene material and mixed evenly, and then made into a flat plate structure. This flat plate scintillator has the characteristics of high light yield and low light attenuation length. Two rows of mutually perpendicular through holes are processed inside the scintillator plate according to the 1mm diameter of the optical fiber to install the optical fiber. The optical fiber is arranged in a parallel array with a spacing of 5mm. The structure of the detector refers to the attached Figure 1 The schematic diagram of the structure is shown in FIG. After the flat scintillator is processed through the array pupil, the scintillating optical fiber is inserted into it, and the silicon photomultiplier tube (SiPM) is coupled to the double-side end faces of the optical fiber for optical signal detection, and the SiPM is connected to the electronics for signal reception and processing, etc. This is an embodiment of a systematic device of a high position resolution detector based on a continuous scintillator and an optical fiber.

[0038] Optionally, the ZnS:Ag material can be added into the polyethylene material and mixed evenly to form a flat plate structure.

[0039] After the incident particle enters the detector of this embodiment, a scintillation light is generated. After the scintillation light is transmitted to the nearby optical fiber, it is transmitted to the SiPM at the end face through the optical fiber and converted into an electrical signal. The signal amplitude measured by the SiPM is proportional to the received light intensity. According to the relationship between the signal amplitude and the position of the incident particle, the position resolution of the detector can be greatly improved through certain mathematical methods. The schematic diagram of the particle incident on the detector is shown in the attached figure. Figure 2 As shown, the signal amplitude measured by the optical fiber on the left side of the particle incident position is A1, and the signal amplitude measured by the optical fiber on the right side of the particle incident position is A2. Using the mathematical model that the signal amplitude is proportional to the light transmission distance, the particle incident position is calculated by the following formula. This calculation method can greatly increase the position resolution of the detector.

[0040]

[0041] Although the specific embodiments of the present invention are disclosed for the purpose of illustration, the purpose is to help understand the content of the present invention and implement it accordingly, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the best embodiment, and the scope of the present invention is subject to the scope defined in the claims.

Claims

1. A continuous scintillator, characterized in that: The invention comprises a transparent or translucent solvent, in which a scintillator material with high light yield and low light attenuation length is uniformly mixed.

2. The continuous scintillator according to claim 1, characterized in that: The solvent is a liquid scintillator solvent, a liquid gel scintillator solvent or a solid scintillator solvent.

3. The continuous scintillator according to claim 1, characterized in that: The scintillator material with high light yield and low light attenuation length is ZnS:Ag material.

4. The continuous scintillator according to claim 1, characterized in that: The scintillator material with high light yield and low light attenuation length is ZnS:Ag and 6 LiF mixed material; ZnS:Ag and 6 LiF is mixed in a ratio of 2:1 to 3:1 and then added into the polyethylene material and mixed evenly.

5. The continuous scintillator according to claim 1, characterized in that: The light transmittance of the solvent is determined according to the light attenuation length of the detector to the continuous scintillator.

6. A method for preparing the continuous scintillator according to claim 1, comprising the steps of: mixing scintillator materials with high light yield and low light attenuation length, adding the mixture into a transparent or translucent solvent and mixing the mixture evenly to obtain a liquid or solid mixture as the continuous scintillator.

7. A high position resolution detector based on the continuous scintillator according to claim 1, characterized in that: An array of optical fibers is arranged in the continuous scintillator, with both ends or one end of each optical fiber located outside the continuous scintillator and coupled to a detector; The continuous scintillator is used to generate scintillation light when particles are incident; The optical fiber is used to receive the scintillation light incident along the side wall of the optical fiber and transmit it to the detector; The detector is used to convert the received optical signal into an electrical signal.

8. The high position resolution detector according to claim 7, characterized in that: The continuous scintillator is provided with a plurality of optical fibers arranged in parallel along a first direction and a plurality of optical fibers arranged in parallel along a second direction, and the first direction is perpendicular to the second direction; or the continuous scintillator is provided with a plurality of optical fibers arranged in parallel along a first direction, a plurality of optical fibers arranged in parallel along the second direction and a plurality of optical fibers arranged in parallel along a third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

9. The high position resolution detector according to claim 7 or 8, characterized in that: The continuous scintillator is a flat plate structure, a barrel structure, a cubic structure, a rectangular parallelepiped structure or a cylindrical structure.

10. A position detection method based on the high position resolution detector according to claim 7, the steps comprising: 1) Recording the electrical signal strength information output by each detector, the optical fiber port corresponding to each detector, and the position information of each optical fiber; 2) Based on the information recorded in step 1), the incident position of the particle is calculated using the center of gravity method.

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