Acid-proof scintillation optical fiber detector

Abstract

The invention relates to an acid-proof scintillation optical fiber detector which comprises a detector shell, a plane cover plate is arranged in the detector shell, a photoelectric detector and a detector electronic unit connected with the photoelectric detector are arranged at the top of the plane cover plate, and one end of the photoelectric detector is connected with an optical fiber collimation coupling body; a detector bottom frame is arranged at the bottom of the planar cover plate, a shading film is arranged in the detector bottom frame, a scintillator is arranged at the top of the detector bottom frame, an optical fiber fixing frame is arranged at the top of the scintillator, a plurality of scintillation optical fibers are sequentially arranged on the optical fiber fixing frame in a U shape at equal intervals, and the ends of the scintillation optical fibers penetrate through the planar cover plate to be connected with an optical fiber collimation coupling body; a light guide is arranged on the top of the optical fiber fixing frame, a light reflecting layer is arranged on the top of the light guide, and the top face of the light reflecting layer is connected with the bottom face of the plane cover plate. The detector can work in a strong oxidizing acid environment for a long time, the detection efficiency and the detection sensitive area of the detector can reach the standard, and meanwhile the problem that the detector is too long in the single direction is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear radiation monitoring, and in particular relates to an acid-proof scintillation optical fiber detector. Background Art

[0002] The scintillation fiber detector is a nuclear radiation scintillator detector. The main difference from the traditional scintillator detector is that the scintillation fiber detector places the scintillation fiber on one side of the scintillator as a light transmission medium to transmit the scintillation light generated by the scintillator to the photoelectric detector. The scintillation fiber detector can be used with different scintillators and probes according to different usage scenarios to detect α, β, γ, neutron and other rays.

[0003] Existing scintillation fiber optic detectors are mostly used for surface contamination detection on hands, feet, and the whole body, or for conventional environmental radiation detection. However, in some scenarios, such as spent fuel reprocessing and some laboratory measurements, these scenarios may have strong oxidizing acid properties, and the objects to be measured may include strong oxidizing acid radioactive liquids in addition to solid waste. When detecting in a strong oxidizing acid environment, strong oxidizing acid gases or liquids will corrode the light reflection layer, causing light leakage and corroding materials such as optical fibers, resulting in a decrease in detection efficiency. After a period of time, the detector cannot perform normal detection tasks. Secondly, currently scintillation fiber optic detectors mainly use photomultiplier tubes and Si PM as photoelectric detectors. Detectors using photomultiplier tubes are too long in a single direction due to the large size of the photomultiplier tubes and the limitation of the optical fiber arrangement. Although detectors using Si PM are small in size, most of them have low detection efficiency. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides an acid-proof scintillation fiber optic detector, which uses a series of acid-resistant materials and structural sealing design, and can work for a long time in a strong oxidizing acid environment. It can also ensure that the detection efficiency and detection sensitive area of ​​the detector meet the standards while avoiding the problem of the detector size being too long in a single direction.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] An acid-proof scintillation optical fiber detector comprises a detector housing, a flat cover plate is arranged inside the detector housing, a photoelectric detector is arranged on the top of the flat cover plate, and a detector electronic unit connected to the photoelectric detector, wherein one end of the photoelectric detector is connected to an optical fiber collimation coupling body;

[0007] A detector bottom frame is provided at the bottom of the plane cover plate, a light shielding film is provided inside the detector bottom frame, a scintillator is provided at the top of the detector bottom frame, a fiber fixing frame is provided at the top of the scintillator, a plurality of scintillating optical fibers are arranged in a U-shape and equidistantly in sequence on the fiber fixing frame, and the ends of the scintillating optical fibers pass through the plane cover plate and are connected to the optical fiber collimation coupling body;

[0008] A light guide is arranged on the top of the optical fiber fixing frame, a light reflecting layer is arranged on the top of the light guide, and the top surface of the light reflecting layer is connected to the bottom surface of the plane cover plate.

[0009] Preferably, a detector waterproof power supply connector and a detector waterproof communication connector are respectively provided on the side of the detector housing, and the detector waterproof power supply connector and the detector waterproof communication connector are both connected to the detector electronic unit.

[0010] Preferably, the detector housing and the flat cover are both made of 316 stainless steel material, and two ribs are longitudinally spaced apart at the bottom of the detector bottom frame, and the ribs divide the scintillation fiber optic detector into three detection sensitive areas.

[0011] Preferably, the joints between the waterproof power supply connector and the detector waterproof communication connector and the detector housing are provided with sealing rings and coated with sealant.

[0012] Preferably, the shading film is made of polished titanium foil, and its reflectivity to wavelengths of 400nm to 700nm is ≥70%.

[0013] Preferably, the scintillating optical fiber is a plastic wave-shifting optical fiber.

[0014] Preferably, the optical fiber fixing frame is made of acrylic material, and a plurality of optical fiber positioning holes for inserting the flashing optical fiber are opened at equal intervals at both ends thereof. The two ends of the flashing optical fiber are respectively inserted into two adjacent optical fiber positioning holes at one end of the optical fiber fixing frame, and exit from two corresponding optical fiber positioning holes at the other end of the optical fiber fixing frame.

[0015] Preferably, the scintillator is a ZnS plastic scintillator, the peak emission wavelength of which is 423 nm.

[0016] Preferably, the light reflecting layer is made of an aluminum-plated film, and its light reflectivity in the wavelength range of 400nm to 500nm is ≥90%.

[0017] Preferably, a handle is provided on the top of the detector housing.

[0018] Technical effects and advantages of the present invention:

[0019] 1. An acid-proof scintillation optical fiber detector provided by the present invention adopts a combined structure of a flat cover plate, a photodetector, a detector electronic unit, an optical fiber collimation coupling body, a detector bottom frame, a light shielding film, an optical fiber fixing frame, a scintillation optical fiber, a scintillator, a light guide and a light reflecting layer in a detector housing, which can not only work for a long time in a strong oxidizing acid environment, but also make the detector meet the detection efficiency and detection sensitive area, and can also avoid the problem of the detector size being too long in the electrical direction;

[0020] The specific manifestations are:

[0021] 1. The detector shell is made of 316 stainless steel, and the waterproof power supply connector, the detector waterproof communication connector, and the joints between the detector bottom frame and the detector shell are all sealed with gaskets and sealing structural adhesive, so that the entire detection device has good sealing performance and acid corrosion resistance;

[0022] 2. The light-shielding film uses a 5μm thick pure titanium foil, which is completely different from the aluminum-plated polyester film often used in conventional detectors. While meeting the basic requirements of light-shielding, maintaining a thin thickness and high light reflectivity, it has excellent acid resistance (especially oxidizing acids represented by nitric acid) and better wear resistance.

[0023] 3. The scintillation optical fiber adopts wave-shifting optical fiber, which is particularly suitable for collecting light from a large side area when multiple fibers are arranged. The detector of the present application fully considers the characteristics that the light transmission efficiency of the wave-shifting optical fiber is lost as the distance increases and as the bending radius decreases. The optical fiber arrangement structure and the photomultiplier tube arrangement structure adopted not only retain the photomultiplier tube with higher detection efficiency, but also solves the problem of the detector size being too long in a single direction caused by the photomultiplier tube as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall explosion structure of the detector of the present invention;

[0025] Figure 2 It is a schematic diagram of the explosion structure of the internal structure of the detector of the present invention.

[0026] Figure numerals: 1, detector housing; 2, flat cover plate; 3, detector bottom frame; 4, light shielding film; 5, scintillating optical fiber; 6, optical fiber fixing frame; 7, scintillator; 8, light guide; 9, light reflecting layer; 10, photoelectric detector; 11, detector waterproof

[0027] Power supply connector; 12. Detector electronic unit; 13. Fiber optic collimation coupling body; 14. Detector waterproof communication connector. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the embodiments given in the accompanying drawings.

[0029] See also Figures 1-2 As shown, an acid-proof scintillation fiber optic detector comprises a detector housing 1, a flat cover plate 2 is arranged inside the detector housing 1, a photoelectric detector 10 is arranged on the top of the flat cover plate 2, and a detector electronic unit 12 connected to the photoelectric detector 10, and one end of the photoelectric detector 10 is connected to a fiber optic collimation coupler 13.

[0030] A detector bottom frame 3 is provided at the bottom of the planar cover plate 2, a light-shielding film 4 is provided inside the detector bottom frame 3, a scintillator 7 is provided at the top of the detector bottom frame 3, the scintillator 7 is a plastic scintillator, and a fiber fixing frame 6 is provided at the top, a plurality of scintillating optical fibers 5 are arranged in a U-shape and equidistantly in sequence on the fiber fixing frame 6, and the ends of the scintillating optical fibers 5 pass through the planar cover plate 2 and are connected to the fiber collimation coupling body 13; a light guide 8 is provided at the top of the fiber fixing frame 6, a light reflecting layer 9 is provided at the top of the light guide 8, and the top surface of the light reflecting layer 9 is connected to the bottom surface of the planar cover plate 2.

[0031] In this embodiment, a detector waterproof power supply connector 11 and a detector waterproof communication connector 14 are respectively provided on the side of the detector housing 1. The power supply voltage of the detector waterproof power supply connector 11 is 12V, and the detector waterproof communication connector 14 is an RS485 communication interface. Sealing rings and sealants are provided at the joints between the detector waterproof power supply connector 11 and the detector waterproof communication connector 14 and the detector housing 1 to achieve a high degree of sealing inside the housing. Finally, the detector waterproof power supply connector 11 and the detector waterproof communication connector 14 are connected to the detector electronic unit 12.

[0032] In this embodiment, the detector housing 1 and the flat cover plate 2 are both made of 316 stainless steel material, thereby providing the detector with acid resistance.

[0033] In this embodiment, two ribs are longitudinally spaced apart at the bottom of the detector bottom frame 3 , and the ribs divide the scintillation fiber detector into three detection sensitive areas. The width of the two ribs is 5 mm.

[0034] In this embodiment, the shading film 4 is made of polished titanium foil, the thickness of the titanium foil is 5 μm, and metallic titanium has excellent resistance to oxidizing acids, especially to nitric acid which is often present in the field of nuclear detection. When the acidic gas / liquid contacts the shading film 4, the shading film 4 can block the acidic gas / liquid for a long time without being corroded and penetrated. It also has good reflective ability, with a reflectivity of ≥70% for wavelengths of 400nm to 700nm, and can reflect the scintillation light emitted by the plastic scintillator 7, thereby further improving the efficiency of the detector.

[0035] In this embodiment, the scintillating optical fiber 5 is a plastic wave-shifting optical fiber, which has the characteristics of having a high absorption rate for light incident from the side of the optical fiber and the scintillation light emitted by the plastic scintillator 7, and can also change the wavelength of the outgoing light, making the outgoing light more suitable for detection by the photodetector 10.

[0036] In this embodiment, the optical fiber fixing frame 6 is made of acrylic material, and a plurality of optical fiber positioning holes for inserting the scintillation optical fiber 5 are opened at equal intervals at both ends thereof. The two ends of the scintillation optical fiber 5 are respectively inserted from two adjacent optical fiber positioning holes at one end of the optical fiber fixing frame 6, and are inserted from two corresponding optical fiber positioning holes at the other end of the optical fiber fixing frame 6; the ends of all the scintillation optical fibers 5 are gathered into a bundle at the exit, and after being bent with a suitable bending radius, enter the optical fiber collimation coupling body 13, contact the photodetector 10 and transmit light into the photodetector 10.

[0037] In this embodiment, the scintillator 7 is a ZnS plastic scintillator, which can respond to both α and β rays at the same time, and has a peak emission wavelength of 423 nm.

[0038] In this embodiment, the light reflecting layer 9 is made of aluminum-plated film, which is mainly used to reflect the scintillation light emitted by the plastic scintillator 7. Its light reflectivity in the wavelength range of 400nm to 500nm is ≥90%, covering the peak wavelength of the light emitted by the plastic scintillator 7.

[0039] In this embodiment, the photodetector 10 uses a photomultiplier tube, which is mainly used to receive the light transmitted by the scintillation optical fiber 5 .

[0040] In this embodiment, the detector electronics unit 12 is a conventional detector circuit, and its main function is to collect and process the electrical signal emitted by the photodetector 10 , which will not be described in detail here.

[0041] In this embodiment, a handle 15 is provided on the top of the detector housing 1 to facilitate the movement of the detection device.

[0042] When the present application is used, the detector is first powered and communicated through the detector waterproof power supply connector 11 and the detector waterproof communication connector 14 on the detector housing 1, and the detector starts detecting at this time; when there is radiation, the radiation first passes through the light shielding film 4 and then irradiates the scintillator 7, which is a 1mm The scintillator is a ZnS plastic scintillator, and is fixed by a light guide 8 and a high-transmittance optical glue. The scintillator 7 emits scintillation light after being irradiated by rays, and most of the scintillation light is absorbed by the scintillation optical fiber 5. The scintillation optical fiber 5 is a 1mm plastic wave-shifting optical fiber, and the spacing between the optical fibers is 1cm. A part of the light not absorbed by the scintillation optical fiber 5 is reflected by the shading film 4 and the light reflecting layer 9, and has a certain probability of being reabsorbed by the scintillation optical fiber 5; the light absorbed by the scintillation optical fiber 5 is transmitted along the optical path through the optical fiber collimation coupler 13 into the photodetector 10. The optical fiber collimation coupler 13 is a plastic cylindrical structure with an aperture of 1.1mm and 20 holes. The optical fiber collimation coupler 13 is tightly attached to the end window surface of the photodetector 10 through a fixed structure, and is filled with optical silicone grease as a coupling material; when the photodetector 10 receives the optical signal, it will convert the optical signal into an electrical signal and transmit it to the detector electronics unit 12. The detector electronics unit 12 collects and processes the electrical signal to finally complete the detection.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An acid-proof scintillation optical fiber detector, characterized in that: The detector comprises a detector housing (1), wherein a plane cover plate (2) is provided in the detector housing (1), a photoelectric detector (10) is provided on the top of the plane cover plate (2), and a detector electronic unit (12) connected to the photoelectric detector (10), wherein one end of the photoelectric detector (10) is connected to an optical fiber collimation coupling body (13); A detector bottom frame (3) is provided at the bottom of the plane cover plate (2), a light shielding film (4) is provided inside the detector bottom frame (3), a scintillator (7) is provided at the top of the detector bottom frame (3), an optical fiber fixing frame (6) is provided at the top of the scintillator (7), a plurality of scintillating optical fibers (5) are arranged in a U-shaped pattern at equal intervals on the optical fiber fixing frame (6), and the ends of the scintillating optical fibers (5) pass through the plane cover plate (2) and are connected to the optical fiber collimation coupling body (13); A light guide (8) is provided on the top of the optical fiber fixing frame (6), a light reflection layer (9) is provided on the top of the light guide (8), and the top surface of the light reflection layer (9) is connected to the bottom surface of the plane cover plate (2).

2. The acid-proof scintillation optical fiber detector according to claim 1, characterized in that: A detector waterproof power supply connector (11) and a detector waterproof communication connector (14) are respectively provided on the side of the detector housing (1), and the detector waterproof power supply connector (11) and the detector waterproof communication connector (14) are both connected to the detector electronic unit (12).

3. The acid-proof scintillation optical fiber detector according to claim 2, characterized in that: The detector housing (1) and the flat cover plate (2) are both made of 316 stainless steel material. Two ribs are longitudinally spaced apart at the bottom of the detector bottom frame (3), and the ribs divide the scintillation optical fiber detector into three detection sensitive areas.

4. The acid-proof scintillation optical fiber detector according to claim 2, characterized in that: The joints between the waterproof power supply connector (11) and the detector waterproof communication connector (14) and the detector housing (1) are both provided with sealing rings and coated with sealing glue.

5. The acid-proof scintillation optical fiber detector according to claim 1, characterized in that: The light-shielding film (4) is made of polished titanium foil, and its reflectivity to wavelengths of 400nm to 700nm is ≥70%.

6. The acid-proof scintillation optical fiber detector according to claim 1, characterized in that: The scintillation optical fiber (5) is a plastic wave-shifting optical fiber.

7. The acid-proof scintillation optical fiber detector according to claim 6, characterized in that: The optical fiber fixing frame (6) is made of acrylic material, and has a plurality of optical fiber positioning holes for inserting the scintillation optical fiber (5) at equal intervals at both ends thereof. The two ends of the scintillation optical fiber (5) are inserted through two adjacent optical fiber positioning holes at one end of the optical fiber fixing frame (6) and exit through two corresponding optical fiber positioning holes at the other end of the optical fiber fixing frame (6).

8. The acid-proof scintillation optical fiber detector according to claim 1, characterized in that: The scintillator (7) is a ZnS plastic scintillator, and its luminescence wavelength peak is 423 nm.

9. The acid-proof scintillation optical fiber detector according to claim 1, characterized in that: The light reflection layer (9) is made of an aluminum-plated film, and its light reflectivity in the wavelength range of 400nm to 500nm is ≥90%.

10. The acid-proof scintillation optical fiber detector according to claim 1, characterized in that: A handle (15) is provided on the top of the detector housing (1).

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