Miniature neutron probe cone face condensing heat-resistant probe

Abstract

A kind of miniature neutron detector conical surface light-concentrating heat-resistant probe, its characteristics include luminous body, light-concentrating cylinder, light-concentrating lens, armored shell, fixing sleeve, compression spring, set screw and optical fiber;Flasher material is made into cylindrical luminous body by using capillary glass tube, the volume of flasher material increases, the neutron activation reaction of flasher material is more sensitive, the light-emitting surface area increases, effectively improve the number of photons generated by flasher material, then light emitted by luminous body is collected, refracted and converged by light-concentrating cylinder and light-concentrating lens, compared with traditional detector probe, effectively reduce the light attenuation of light signal in the process of optical fiber transmission due to random angle incidence, different energy level photon distribution is more uniform and concentrated, the signal strength after conversion is strong, signal pulse accumulation is less, it is easier to be read, greatly improve the detection efficiency of detector, have good enlightenment effect on the technical problems faced by the field, have good popularization and application value.

Description

Technical Field

[0001] This invention relates to the field of neutron detector technology, and more particularly to a conical conical focusing heat-resistant probe for a miniature neutron detector. Background Technology

[0002] Currently, neutron detector probes used in narrow, high-temperature, and strongly electromagnetically interfered small-aperture environments generally consist of an armored housing, an elastic element, a light emitter, and an optical fiber. The armored housing is a cylindrical structure with one end closed and the other open. The elastic element, the light emitter, and the optical fiber tip are sequentially inserted into the inner cavity of the armored housing through the open end. The optical fiber tip is directly or indirectly fixedly connected to the armored housing. The elastic element uses its own elasticity to force the light emitter to press firmly against the end face of the optical fiber tip. The optical fiber is generally made of plastic or quartz, but plastic is not suitable for use in high-temperature environments due to its poor heat resistance.

[0003] Quartz optical fiber is brittle and has many limitations in use. For example, the diameter of a single quartz optical fiber is very small when meeting the requirements for length and bending radius, resulting in a small contact end face diameter. The accuracy of the light incident angle is high, and the photon reception rate is low, which leads to low probe efficiency and directly affects the detection efficiency of the detector.

[0004] Meanwhile, the small coupling end face between the emitting element and the optical fiber leads to severe light dispersion, resulting in a limited number of photons received by the optical fiber. Consequently, the light signal intensity reaching the detector through the optical fiber is weak. Furthermore, the direct coupling between the emitting element and the optical fiber results in random photon emission angles and random incident angles entering the optical fiber. This leads to completely random light attenuation in the optical fiber. As a result, after the incident photons attenuate during transmission through the optical fiber, the neutron pulse signal obtained after processing by the photomultiplier tube and electronic system contains a lot of pulse accumulation, resulting in poor clarity and intensity. This not only increases the difficulty of subsequent processing but also reduces the accuracy of neutron counting, leading to extremely low detector efficiency. Summary of the Invention

[0005] This invention proposes a conical focusing heat-resistant probe for a miniature neutron detector, which can improve the probe's detection efficiency and sensitivity while meeting heat resistance requirements, thereby improving the detector's detection efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A miniature neutron detector cone-shaped focusing heat-resistant probe, characterized by a light emitter, a focusing tube, a focusing lens, an armored shell, a fixing sleeve, a compression spring, a set screw, and an optical fiber;

[0008] The light-emitting body is composed of a capillary glass tube and scintillator material powder. The scintillator material powder fills the capillary glass tube, filling the inner cavity of the capillary glass tube. The capillary glass tube of the light-emitting body is arranged on the axis of the focusing tube and is coaxial with the focusing tube.

[0009] The focusing tube is a conical tube with a smooth mirror surface on the inner wall. A focusing lens is provided at the large opening end of the focusing tube. The focusing lens is a hemispherical convex lens made of colorless optical glass. The flat bottom surface of the focusing lens is directly coupled to the large opening end face of the focusing tube, and the top of the convex spherical surface of the focusing lens is directly coupled to the core wire port section of the optical fiber.

[0010] The optical fiber includes an outer armor layer and a core wire, wherein the core wire is made of quartz, and the outer armor layer at the end of the optical fiber is provided with external threads.

[0011] The armor shell is a tubular shape with openings at both ends. The openings at both ends of the armor shell are respectively provided with a first internal thread and a second internal thread. One end of the first internal thread is connected to the external thread of the outer armor layer of the optical fiber, so as to detachably fix the armor shell to the optical fiber. The inner tube at one end of the second internal thread is provided with the fixing sleeve, the compression spring and the set screw in sequence from the inside to the outside.

[0012] The fixing sleeve is a hollow tube coaxial with the armor shell. The outer diameter of the fixing sleeve is in sliding fit with the inner diameter of the armor shell. One end of the capillary glass tube of the light-emitting body is inserted into the fixing sleeve and in friction fit with the inner hole of the fixing sleeve. The other part of the capillary glass tube is the same length as the focusing tube. The clamping spring is pressed on the fixing sleeve. After tightening the set screw, the focusing tube is pressed by the fixing sleeve, thereby pressing the top of the spherical surface of the focusing lens onto the port section of the optical fiber core.

[0013] A further solution is: in order to prevent the capillary glass tube of the light-emitting body from coming out of the fixed sleeve due to insufficient friction between the fixed sleeve and the capillary glass tube when the fixed sleeve is under pressure, a cover plate is provided between the fixed sleeve and the compression spring to block the inner hole of the fixed sleeve, and the compression spring directly contacts the cover plate.

[0014] A further solution is: in order to increase the light incident aperture and reduce the incident accuracy requirements, the optical fiber is a beam guide, which gathers multiple optical fiber filaments into a bundle and is used for guiding light. The beam guide includes an outer armor layer, and the front end of the outer armor layer is provided with an external thread. The beam guide is detachably connected to one end of the first internal thread of the probe armor shell through the external thread of the outer armor layer.

[0015] A further solution is to improve the light-gathering effect by making the light-gathering tube taper less than or equal to 60°, as the light-gathering effect is better within this taper range.

[0016] A method for installing the above-mentioned conical focusing heat-resistant probe of a miniature neutron detector is characterized by the following steps:

[0017] Step 1: Insert the capillary glass tube filled with scintillator material into the fixing sleeve, and then put the condenser tube on the rest of the capillary glass tube with the larger end of the condenser tube facing upwards. Then place the hemispherical condenser lens with the flat side facing downwards on the larger end of the condenser tube.

[0018] Step 2: Connect the threaded inner hole of the first internal thread end of the armor shell to the free end of the optical fiber connected to the neutron detector at the other end, and fix it with the external thread of the outer armor layer of the optical fiber. Then, align the port of the second internal thread end of the armor shell downward with the upper end of the component assembled in Step 1, and then push the component upward from the second internal thread end into the armor shell until it stops when it is resisted by the cross section of the core wire port of the optical fiber.

[0019] Step 3: Insert the compression spring into the second internal thread port of the armor shell, and finally install the set screw and tighten it to complete the probe installation.

[0020] A further solution is to prevent insufficient friction between the fixing sleeve and the capillary glass tube from causing the glass tube to come out of the fixing sleeve and hit the end of the set screw on the side of the compression spring. Before placing the compression spring in step 3, a cover plate is installed between the compression spring and the fixing sleeve to block the inner hole of the fixing sleeve, and then the compression spring presses it in place.

[0021] A neutron detection method based on the aforementioned probe and neutron detector is characterized by placing the probe close to a neutron source, whereby the scintillator material in the capillary glass tube is excited by neutrons and emits light. The emitted photons are collected and refracted by a focusing tube, and then the incident angle of the photons entering the optical fiber is adjusted by a focusing lens. The photons are transmitted through the optical fiber to a photomultiplier tube and converted into electrical signals. After processing by an electronic system, a readable neutron signal is obtained, and then the detection signal data is obtained through existing detector signal processing methods.

[0022] The beneficial effects of this invention are as follows: By using a capillary glass tube to fabricate a cylindrical scintillator material, the volume of the scintillator material increases, making its neutron excitation reaction more sensitive and increasing the luminous surface area, effectively increasing the number of photons generated by the scintillator material. Furthermore, the use of a beam guide composed of multiple optical fiber filaments increases the incident aperture of the photons into the optical fiber, reducing the incident accuracy requirements and improving the optical fiber's photon reception efficiency. Then, a focusing tube and a focusing lens are used to collect, refract, and converge the light emitted by the scintillator. Compared to traditional detector probes, this effectively reduces light attenuation caused by random angles of incidence during optical fiber transmission. The distribution of photons at different energy levels is more uniform and concentrated, resulting in a stronger converted signal with less signal pulse accumulation, making it easier to read. In conventional detection experiments, compared to existing detector probes, this significantly improves the detector's detection efficiency. It provides valuable insights into the technical problems faced in this field and has significant potential for widespread application. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the internal structure of an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0026] Example 1

[0027] A miniature neutron detector cone-shaped focusing heat-resistant probe includes a light emitter 1, a focusing tube 2, a focusing lens 3, an armored shell 4, a fixing sleeve 5, a compression spring 6, a set screw 7, and an optical fiber 8;

[0028] The light-emitting body 1 is composed of a capillary glass tube and scintillator material powder. The scintillator material powder fills the capillary glass tube, filling the inner cavity of the capillary glass tube. The capillary glass tube of the light-emitting body 1 is arranged on the axis of the focusing tube 2 and is coaxial with the focusing tube 2.

[0029] The focusing tube 2 is a conical tube with a smooth mirror surface on its inner wall. A focusing lens 3 is provided at the large opening end of the focusing tube 2. The focusing lens 3 is a hemispherical convex lens made of colorless optical glass. The flat bottom surface of the focusing lens 3 is directly coupled to the large opening end face of the focusing tube 2, and the top of the convex spherical surface of the focusing lens 3 is directly coupled to the core wire port section of the optical fiber 8.

[0030] The optical fiber 8 includes an outer armor layer and a core wire, the core wire being made of quartz, and the outer armor layer at the end of the optical fiber 8 having external threads.

[0031] The armor shell 4 is a tubular shape with openings at both ends. The openings at both ends of the armor shell are respectively provided with a first internal thread 41 and a second internal thread 42. One end of the first internal thread 41 is connected to the external thread of the outer armor layer of the optical fiber 8, so that the armor shell 4 and the optical fiber 8 are detachably fixed. The inner tube at one end of the second internal thread 42 is provided with the fixing sleeve 5, the compression spring 6, and the set screw 7 in sequence from the inside to the outside.

[0032] The fixing sleeve 5 is a hollow tube coaxial with the armor shell 4. The outer diameter of the fixing sleeve 5 is in sliding fit with the inner diameter of the armor shell 4. One end of the capillary glass tube of the light-emitting body 1 is inserted into the fixing sleeve 5 and frictionally fits with the inner hole of the fixing sleeve 5. The other part of the capillary glass tube is the same length as the focusing tube 2. The clamping spring 6 is pressed on the fixing sleeve 5. After tightening the set screw 7, the focusing tube 2 is pressed by the fixing sleeve 5, and the top of the spherical lens 3 is pressed on the port section of the core wire of the optical fiber 8.

[0033] To prevent the capillary glass tube of the light-emitting body 1 from coming out of the fixed sleeve 5 due to insufficient friction between the fixed sleeve 5 and the capillary glass tube when it is under pressure, a cover plate 9 is provided between the fixed sleeve 5 and the compression spring 6 to block the inner hole of the fixed sleeve 5, and the compression spring 6 is in direct contact with the cover plate 9.

[0034] The optical fiber 8 is a beam guide, which gathers multiple optical fiber filaments into a bundle for guiding light. The beam guide includes an outer armor layer with an external thread at the front end. The beam guide is detachably connected to one end of the first internal thread 41 of the probe armor shell 4 through the external thread of the outer armor layer.

[0035] The concentrator tube 2 has a taper of less than or equal to 60°.

[0036] The scintillator material is 6 LiF / ZnS(Ag) mixture.

[0037] Example 2

[0038] A method for installing the above-mentioned conical focusing heat-resistant probe of a miniature neutron detector comprises the following steps:

[0039] Step 1: Insert the capillary glass tube light emitter 1, which is filled with scintillator material, into the fixing sleeve 5. Then, put the condenser tube 2 on the rest of the capillary glass tube, with the large opening of the condenser tube 2 facing upwards. Then, place the hemispherical condenser lens 3 with its flat surface facing downwards on the large opening of the condenser tube 2.

[0040] Step 2: Connect the threaded inner hole of the first internal thread 41 of the armor shell 4 to the free end of the optical fiber 8 connected to the neutron detector at the other end, and fix it with the thread of the outer armor layer of the optical fiber 8. Then, align the port of the second internal thread 42 of the armor shell 4 downward with the upper end of the component assembled in Step 1, and push the component upward from the second internal thread 42 end into the armor shell 4 until it stops when it is resisted by the cross section of the core wire port of the optical fiber 8.

[0041] Step 3: Insert the compression spring 6 into one end of the second internal thread 42 of the armor shell 4, and finally insert the set screw 7 and tighten it to complete the probe installation.

[0042] To prevent insufficient friction between the fixing sleeve 5 and the capillary glass tube from causing the glass tube to come out of the fixing sleeve 5 and hit the end of the set screw 7 on the side of the compression spring 6, before placing the compression spring 6 in step 3, a cover plate 9 is installed between the compression spring 6 and the fixing sleeve 5 to block the inner hole of the fixing sleeve 5, and then the compression spring 6 presses it in place.

[0043] Example 3

[0044] A neutron detection method based on the aforementioned probe and neutron detector is characterized by placing the probe close to a neutron source, whereby the scintillator material in the capillary glass tube is excited by neutrons and emits light. The emitted photons are collected and refracted by a focusing tube, and then the incident angle of the photons entering the optical fiber is adjusted by a focusing lens. The photons are transmitted through the optical fiber to a photomultiplier tube and converted into electrical signals. After processing by an electronic system, a readable neutron signal is obtained, and then the detection signal data is obtained through existing detector signal processing methods.

[0045] Example 4

[0046] Experimental data: The following conclusions can be drawn from Tables 1 to 3:

[0047] 1. High detection efficiency. As can be seen from the count rate change trend in Table 1, the detector not only meets the simulation analysis results of the count rate change trend when the position changes, but also has higher detection efficiency compared with the detector using existing probes.

[0048] 2. The detector is resistant to high temperatures. As shown in Table 2, the detector can maintain a stable count rate in a high-temperature environment of 200℃.

[0049] 3. The detector using the probe of this invention has high sensitivity. As shown in Table 3, at 90cm, the count rate of the detector using the probe of this invention is 1320cps and 620cps at the initial power and 1 / 2 power, respectively. This shows that when the power changes, the count rate can change consistently according to the power change, and provide real-time detection data as the detection depth changes. At the same time, the neutron count rate is basically stable during the counting time with very small changes, which is sufficient to prove the stability of the detector operation.

[0050] Table 1. Tests conducted at room temperature.

[0051]

[0052] Table 2. Tests under high temperature conditions

[0053]

[0054] Table 3 In-heap test data

[0055]

Claims

1. A conical focusing heat-resistant probe for a miniature neutron detector, characterized in that... It includes a light source, a condenser tube, a condenser lens, an armored housing, a fixing sleeve, a compression spring, a set screw, and an optical fiber; The light-emitting body is composed of a capillary glass tube and scintillator material powder. The scintillator material powder fills the capillary glass tube, filling the inner cavity of the capillary glass tube. The capillary glass tube of the light-emitting body is arranged on the axis of the focusing tube and is coaxial with the focusing tube. The focusing tube is a conical tube with a smooth mirror surface on the inner wall. A focusing lens is provided at the large opening end of the focusing tube. The focusing lens is a hemispherical convex lens made of colorless optical glass. The flat bottom surface of the focusing lens is directly coupled to the large opening end face of the focusing tube, and the top of the convex spherical surface of the focusing lens is directly coupled to the core wire port section of the optical fiber. The optical fiber includes an outer armor layer and a core wire, wherein the core wire is made of quartz, and the outer armor layer at the end of the optical fiber is provided with external threads. The armor shell is a tubular shape with openings at both ends. The openings at both ends of the armor shell are respectively provided with a first internal thread and a second internal thread. One end of the first internal thread is connected to the external thread of the outer armor layer of the optical fiber, so as to detachably fix the armor shell to the optical fiber. The inner tube at one end of the second internal thread is provided with the fixing sleeve, the compression spring and the set screw in sequence from the inside to the outside. The fixing sleeve is a hollow tube coaxial with the armor shell. The outer diameter of the fixing sleeve is in sliding fit with the inner diameter of the armor shell. One end of the capillary glass tube of the light-emitting body is inserted into the fixing sleeve and in friction fit with the inner hole of the fixing sleeve. The other part of the capillary glass tube is the same length as the focusing tube. The clamping spring is pressed on the fixing sleeve. After tightening the set screw, the focusing tube is pressed by the fixing sleeve, thereby pressing the top of the spherical surface of the focusing lens onto the port section of the optical fiber core.

2. The miniature neutron detector cone-shaped focusing heat-resistant probe as described in claim 1, characterized in that... A cover plate is provided between the fixing sleeve and the compression spring to block the inner opening of the fixing sleeve, and the compression spring is in direct contact with the cover plate.

3. A miniature neutron detector cone-shaped focusing heat-resistant probe as described in claim 1 or 2, characterized in that... The optical fiber is a beam guide, which combines multiple optical fiber filaments into a bundle for guiding light. The beam guide includes an outer armor layer with an external thread at the front end. The beam guide is detachably connected to one end of the first internal thread of the probe armor shell through the external thread of the outer armor layer.

4. A miniature neutron detector cone-shaped focusing heat-resistant probe as described in claim 1 or 2, characterized in that... The concentrator tube has a taper of 60° or less.

5. The miniature neutron detector cone-shaped focusing heat-resistant probe as described in claim 3, characterized in that... The concentrator tube has a taper of 60° or less.

6. The installation method of any one of the conical focusing heat-resistant probes for a miniature neutron detector as described in claims 1 to 5, characterized by the following steps: Step (1): Insert the capillary glass tube filled with scintillator material into the fixing sleeve, and then put the condenser tube on the rest of the capillary glass tube with the large opening end of the condenser tube facing upwards, and then place the hemispherical condenser lens with the flat surface facing downwards on the large opening end of the condenser tube. Step (2): Connect the threaded inner hole of the first internal thread of the armor shell to the free end of the optical fiber connected to the neutron detector at the other end, and fix it with the thread of the outer armor layer of the optical fiber. Then, align the port of the second internal thread of the armor shell downward with the upper end of the component assembled in step (1), and push the component upward from the second internal thread into the armor shell until it is stopped when it is resisted by the cross section of the core wire port of the optical fiber. Step (3): Insert the compression spring into the second internal thread port of the armor shell, and finally install the set screw and tighten it to complete the probe installation.

7. The installation method of the conical focusing heat-resistant probe for a miniature neutron detector as described in claim 6, characterized in that... Before placing the compression spring in step (3), a cover plate is installed between the compression spring and the fixing sleeve to block the inner hole of the fixing sleeve, and then the compression spring presses it.

8. A neutron detection method based on a neutron detector employing the probe described in any one of claims 1 to 5, characterized in that: When the probe is brought close to the neutron source, the scintillator material in the capillary glass tube is excited by the neutron and emits light. The emitted photons are collected and refracted by the focusing tube, and then the incident angle of the photons entering the optical fiber is adjusted by the focusing lens. The photons are transmitted through the optical fiber to the photomultiplier tube and converted into electrical signals. After being processed by the electronic system, a readable neutron signal is obtained. Then, the detection signal data is obtained by existing detector signal processing methods.

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