High-temperature-resistant scintillator coupling optical fiber neutron detector

Abstract

The utility model discloses a high-temperature-resistant scintillator coupling optical fiber neutron detector, which comprises a scintillation crystal used for detecting ray particles, a transmission optical fiber connected and coupled with one end of the scintillation crystal, a photomultiplier connected and coupled with the other end of the transmission optical fiber, and a power supply interface and a signal interface which are respectively arranged on the photomultiplier, the surface of the scintillation crystal is coated with a reflecting layer and is fixed in the metal end cap, the surface of the transmission optical fiber is coated with a high-temperature-resistant protective layer and is sleeved in the metal armored sheath, one end of the metal armored sheath is connected with the metal end cap, and the other end of the metal armored sheath is connected with an interface, coupled with the transmission optical fiber, on the photomultiplier. According to the utility model, through the improved design of the packaging structure of the high-temperature-resistant quartz optical fiber, the metal armoring design, the high-temperature-resistant scintillation crystal, the high-temperature-resistant optical fiber glue and the like, the structure of the detector can tolerate the high temperature of 300 DEG C.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of radiation detection technology, specifically, it is a kind of high-temperature type scintillator coupling optical fiber neutron detector. BACKGROUND

[0002] In the nuclear industry and nuclear science research, neutron detection technology is a crucial link. Neutron detector can detect and measure the intensity and energy distribution of neutrons, which has important significance for the monitoring of nuclear reactors, nuclear medical imaging, detection of radioactive substances and nuclear safety. Scintillator coupling optical fiber neutron detector is widely used due to its high sensitivity, fast response and good energy resolution. However, these detectors have obvious deficiencies in performance stability and adaptability in high temperature and strong radiation environment, which limits their application in extreme environment.

[0003] The existing scintillator coupling optical fiber neutron detector is usually composed of scintillator material, optical fiber and photodetector. In high temperature environment, scintillator material may be thermally degraded, resulting in reduced light output and energy resolution. At the same time, the refractive index of optical fiber may change and the optical loss may increase at high temperature, affecting the transmission efficiency of signal. In strong radiation environment, scintillator material and optical fiber may be damaged by radiation, resulting in material performance degradation, such as reduced scintillation efficiency, increased dark current, etc. In addition, the sealing structure of the detector is also a key factor in high temperature and strong radiation environment, because poor sealing may lead to environmental gas intrusion, and insufficient mechanical stability may cause structural deformation, affecting the long-term stability and reliability of the detector.

[0004] In high temperature, strong radiation environment such as nuclear reactor, the packaging structure of traditional scintillator coupling optical fiber neutron detector often cannot provide sufficient protection, so that the service life and performance stability of the detector under these extreme conditions are seriously affected. Therefore, it is of great significance to design a scintillator coupling optical fiber neutron detector packaging structure that can maintain high performance in high temperature environment, in order to improve the environmental adaptability and prolong the service life of the detector. UTILITY MODEL CONTENT

[0005] In view of the problems existing in the prior art, the utility model provides a high-temperature-resistant scintillator coupling optical fiber neutron detector, which improves the adaptability and neutron gamma discrimination ability of the detector in high temperature environment by improving the packaging structure of the detector.

[0006] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0007] A high-temperature scintillator-coupled fiber optic neutron detector includes a scintillator crystal for detecting X-ray particles, a transmission fiber coupled to one end of the scintillator crystal, a photomultiplier tube coupled to the other end of the transmission fiber, and a power supply interface and a signal interface respectively disposed on the photomultiplier tube. The surface of the scintillator crystal is covered with a reflective layer and fixed inside a metal end cap. The surface of the transmission fiber is covered with a high-temperature resistant protective layer and encased in a metal armor sheath. One end of the metal armor sheath is connected to the metal end cap, and the other end is connected to the interface on the photomultiplier tube coupled to the transmission fiber.

[0008] Specifically, the scintillation crystal is a cubic LiCAF scintillation crystal with a thickness of 0.6 mm.

[0009] Specifically, the transmission optical fiber is a quartz optical fiber with a core diameter of 600-1000um.

[0010] Specifically, one end of the transmission optical fiber coupled to the scintillation crystal is exposed 2cm-5cm from the metal armor sheath, and the end faces of the scintillation crystal and the transmission optical fiber are bonded together using 353ND fiber curing adhesive.

[0011] Specifically, one end of the transmission optical fiber coupled to the photomultiplier tube is configured as a universal optical fiber connector, which is connected and coupled to the universal optical fiber interface configured on the photomultiplier tube.

[0012] Specifically, the reflective layer is made of aluminum foil and wraps the ends of the scintillation crystal and the transmission fiber coupled to the scintillation crystal.

[0013] Specifically, the metal end cap is made of tungsten alloy material. After the scintillation crystal and the end of the transmission optical fiber are placed inside the metal end cap, the opening of the metal end cap is sealed to the metal armor sheath with high-temperature glue or welding.

[0014] Specifically, the protective layer is a coating made of polyimide or metal.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) This invention improves the packaging structure of high-temperature resistant quartz optical fiber, metal armor design, high-temperature scintillation crystal, and high-temperature resistant optical fiber adhesive, enabling the detector to operate in high-temperature environments below 300℃. Compared with the existing ordinary crystal-coupled plastic optical fiber structure, this greatly enhances the detector's high-temperature resistance. This invention has a simple and ingenious design, stable structure, and excellent performance, making it suitable for application in high-temperature neutron detectors.

[0017] (2) This utility model improves the neutron gamma discrimination effect of scintillator coupled optical fiber by using a small-sized LiCAF crystal coupled with a metal shielding shell. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0020] Example

[0021] like Figure 1 As shown, the high-temperature scintillator-coupled fiber optic neutron detector includes a scintillator crystal 1 for detecting X-ray particles, a transmission fiber 4 coupled to one end of the scintillator crystal, a photomultiplier tube 7 coupled to the other end of the transmission fiber, and a power supply interface 8 and a signal interface 9 respectively disposed on the photomultiplier tube. The surface of the scintillator crystal 1 is covered with a reflective layer 2 and fixed inside a metal end cap 3. The surface of the transmission fiber 4 is covered with a high-temperature resistant protective layer 5 and is fitted inside a metal armor sleeve 6. One end of the metal armor sleeve is connected to the metal end cap, and the other end is connected to the interface of the transmission fiber coupled to the photomultiplier tube.

[0022] The specific configurations of each component are as follows:

[0023] The scintillation crystal is a cubic LiCAF scintillation crystal with a thickness of 0.6 mm and the chemical formula Eu:LiCaAlF6. It has high light yield and thermal neutron detection efficiency, is non-hygroscopic, and still has radiation detection capability at 250℃.

[0024] The transmission optical fiber is made of quartz fiber with a core diameter of 600-1000µm and a length that can be customized from 1-10m according to actual needs. The protective layer is a coating made of polyimide or metal material, which can withstand high temperatures of 300℃. The outermost layer is protected by a stainless steel armor sheath. The end of the transmission optical fiber coupled to the scintillation crystal is exposed 2cm-5cm from the metal armor sheath, and the end faces of the scintillation crystal and the transmission optical fiber are bonded using 353ND fiber curing adhesive. This adhesive can be used for extended periods at 300℃. Before bonding, the end faces of the optical fiber and the crystal are cleaned with alcohol. The adhesive is an AB glue, which is mixed and evenly applied to the joint between the crystal and the optical fiber end faces. After 12 hours, the adhesive solidifies and dries; the solidification time can be shortened by heating. The end of the transmission optical fiber coupled to the photomultiplier tube is configured with a universal fiber optic connector such as SMA or FC, which connects and couples with the universal fiber optic interface on the photomultiplier tube. Silicone oil can be applied during coupling to improve light guiding efficiency.

[0025] The reflective layer is made of aluminum foil, and the ends of the scintillation crystal and the transmission fiber coupled to the scintillation crystal are wrapped after they are bonded together to reduce the scattering loss of the scintillation crystal's light emission.

[0026] The metal end cap is made of tungsten alloy or high-density metal material and can shield gamma rays. Its specific dimensions can be configured as follows: diameter 7mm, length 5cm, wall thickness 2mm, open at one end and closed at the other. The opening size matches the size of the scintillation crystal and the optical fiber. After the scintillation crystal and the transmission optical fiber are inserted into the metal end cap, the opening of the metal end cap is sealed to the metal armor sheath using high-temperature adhesive or welding.

[0027] The photomultiplier tube PMT can be replaced by a silicon photomultiplier tube (SiPM).

[0028] When this invention is in operation, neutrons or other rays excite the scintillation crystal to generate photons. The excited photons are then effectively transmitted over a long distance to the photomultiplier tube via a coupled optical fiber, where they are amplified and output as electrical pulse signals.

[0029] The energy deposition of gamma rays and thermal neutrons of different energies within a 0.6 mm cubic LiCAF crystal was simulated using Monte Carlo software. The upper limit of gamma ray deposition at 662 keV was 457 keV, at 1.2 MeV it was 988 keV, and at 2 MeV it was 1.1 MeV. Meanwhile, the energy deposition of thermal neutrons within the crystal... 6 The 4.78 MeV energy generated by the Li reaction can be completely deposited. It can be seen that the detector of this invention has excellent neutron detection capability.

[0030] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any changes made based on the design principles of this utility model, or any non-creative changes made on this basis, shall fall within the scope of protection of this utility model.

Claims

1. A high-temperature resistant scintillator-coupled fiber optic neutron detector, characterized in that, The device includes a scintillation crystal for detecting X-ray particles, a transmission optical fiber coupled to one end of the scintillation crystal, a photomultiplier tube coupled to the other end of the transmission optical fiber, and a power supply interface and a signal interface respectively disposed on the photomultiplier tube. The surface of the scintillation crystal is covered with a reflective layer and fixed inside a metal end cap. The surface of the transmission optical fiber is covered with a high-temperature resistant protective layer and is fitted inside a metal armor sheath. One end of the metal armor sheath is connected to the metal end cap, and the other end is connected to the interface on the photomultiplier tube coupled to the transmission optical fiber.

2. The high-temperature scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, The scintillation crystal is a cubic LiCAF scintillation crystal with a thickness of 0.6 mm.

3. The high-temperature scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, The transmission optical fiber is made of quartz optical fiber with a core diameter of 600-1000um.

4. The high-temperature resistant scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, The end of the transmission optical fiber coupled to the scintillation crystal is exposed 2cm-5cm from the metal armor sheath, and the end faces of the scintillation crystal and the transmission optical fiber are bonded together using 353ND fiber curing adhesive.

5. The high-temperature scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, One end of the transmission optical fiber coupled to the photomultiplier tube is configured as a universal optical fiber connector, which is connected and coupled to the universal optical fiber interface configured on the photomultiplier tube.

6. The high-temperature scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, The reflective layer is made of aluminum foil and wraps the ends of the scintillation crystal and the transmission fiber coupled to the scintillation crystal.

7. The high-temperature resistant scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, The metal end cap is made of tungsten alloy. After the scintillation crystal and the end of the transmission optical fiber are placed inside the metal end cap, the opening of the metal end cap is sealed to the metal armor sheath with high-temperature glue or welding.

8. The high-temperature scintillator-coupled fiber optic neutron detector according to claim 1, characterized in that, The protective layer is a coating made of polyimide or metal.

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