Portable neutron gamma detection system based on NaIL crystal

Abstract

The invention belongs to the field of nuclear radiation detection systems, and provides a portable neutron gamma detection system based on a NaIL crystal, the portable neutron gamma detection system comprises a detection device, a tablet computer, a support and a handle, the support and the handle are installed on the detection device through a plurality of groups of fastening bolts and spring washers, the tablet computer is fixed on the support through a buckle, and the handle is fixed on the support through a buckle. The detection device comprises a shell, a polyethylene moderator, a NaIL crystal, a photomultiplier, a front-end electronics part, a rear-end electronics part and a wireless communication antenna. The device is simple in structure and easy to hold and use or carry by a backpack, only one detection element is used, the structure of the detection device is greatly simplified, the front-end electronics part and the rear-end electronics part only need to consider processing of one path of signals, the equipment cost and the design difficulty are remarkably reduced, and the reliability is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the field of nuclear radiation detection systems, and in particular relates to a portable neutron gamma detection system based on NaIL crystals. Background Art

[0002] Neutron and gamma ray measurement is widely needed in radiation protection, radioactive source management, nuclear emergency response, industrial applications, environmental protection, security, and counter-terrorism. Traditional nuclear radiation detection systems require both a neutron detector (based on a helium-3 proportional tube or semiconductor detector) and a gamma detector (based on an ionization chamber or Geiger-Müller counter, plastic scintillator, crystal scintillator, semiconductor detector), each equipped with a pulse signal amplification circuit. The digital signal processing circuit design is complex, leading to high equipment costs. Furthermore, the difficulty in reducing the size and weight of these devices makes them difficult to design into portable instruments. With the development of new detector elements and pulse waveform discrimination technologies, significant progress has been made in neutron and gamma ray detection using only one detector element. However, mature portable instruments and related patents are still lacking. Summary of the Invention

[0003] The purpose of the present invention is to overcome the problems of complex structure, high cost and difficulty in designing portable instruments in traditional nuclear radiation detection systems when realizing the measurement and identification of neutrons and gamma rays. A portable neutron gamma detection system based on NaIL crystal is proposed, which can greatly reduce the complexity of the system structure, material cost and design difficulty.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a portable neutron gamma detection system based on NaIL crystal, including a detection device, a tablet computer, a bracket, and a handle. The bracket and handle are installed on the detection device through multiple sets of fastening bolts and spring washers, and the tablet computer is fixed to the bracket by a snap.

[0005] The detection device comprises a housing, a polyethylene moderator, a NaIL crystal, a photomultiplier tube, a photomultiplier tube base, a front-end electronics section, a back-end electronics section, a battery compartment, a lithium battery pack, and a wireless communication antenna. The polyethylene moderator is mounted on the housing via multiple sets of fastening bolts and spring washers. The NaIL crystal, photomultiplier tube, photomultiplier tube base, and front-end electronics section are packaged as a whole, with the NaIL crystal fully inserted into the polyethylene moderator. The photomultiplier tube base and front-end electronics section are mounted on the housing via multiple sets of fastening bolts and spring washers. The back-end electronics section, the battery compartment, and the lithium battery pack are mounted on the housing via multiple sets of fastening bolts and spring washers. The wireless communication antenna and waterproof aviation connector are mounted on the housing via a nut, a spring washer, and a sealing ring. The photomultiplier tube base and front-end electronics section are connected to the back-end electronics section via a connector and a shielded cable. The back-end electronics section is connected to the battery compartment and the lithium battery pack via a connector and a wire. The back-end electronics section is connected to the wireless communication antenna via a connector and a shielded cable.

[0006] In the above technical solution, NaIL crystal is used as a detection element, and waveform discrimination and ray discrimination functions are realized based on the different luminescence characteristics of neutrons and gamma rays in the crystal.

[0007] In the above technical solution, polyethylene is used as the neutron moderator material, and the thickness of the moderator is 5 cm to 7 cm, which can take into account a higher neutron moderation efficiency while ensuring that the equipment is small in size and easy to use.

[0008] In the above technical solution, the front-end electronics part only uses one current-sensitive preamplifier circuit, and the back-end electronics part only uses one digital sampling circuit. The equipment cost and design difficulty are significantly reduced, and the reliability is significantly improved.

[0009] In the above technical solution, the NaIL crystal, photomultiplier tube, photomultiplier tube base and front-end electronic parts are packaged as a whole and covered with a rubber sleeve for vibration reduction.

[0010] In the above technical solution, the detection device is connected to the adapter using a waterproof aviation connector to further improve the environmental adaptability of the device, and the back-end electronic part is connected to the waterproof aviation connector through a connector and a shielded cable.

[0011] In the above technical solution, the detection device and the tablet computer communicate wirelessly via WIFI and Bluetooth, which reduces the number of accessories such as connecting wires and is more convenient to use.

[0012] The tablet computer is equipped with a touch screen, a speaker, multiple I / O interfaces, multiple function keys, a large-capacity polymer lithium-ion battery, an adapter (tablet), WIFI, Bluetooth, 4G communication functions, a GPS module, and a Beidou module. The required software is pre-installed and the following functions can be achieved by calling the tablet computer resources: drawing PSD-energy spectrum, neutron and gamma ray discrimination, calculating and displaying neutron count rate, gamma ray count rate, gamma ray energy spectrum, gamma dose rate and other information, drawing dose rate distribution diagram, distinguishing the type and location of radiation sources, sound and light alarm, etc., which reduces the difficulty of equipment research and development and production costs.

[0013] When the device is carried in a backpack, the detection device, tablet computer, adapter, etc. are placed on a fixed position of the foam material, and then the whole device is placed in the backpack. At this time, the tablet computer can also be used alone by hand to observe the measurement results and the sound and light alarm information.

[0014] Compared with the prior art, the portable neutron gamma detection system based on NaIL crystal of the present invention has the following beneficial effects:

[0015] 1. Using only one detection element greatly simplifies the structure of the detection device. NaIL crystals, as an inorganic crystal scintillator with a relatively mature growth process and large growth volume, can more easily achieve a higher response to neutrons and gamma rays at the same time compared to other detection elements.

[0016] 2. The front-end electronics and back-end electronics only need to consider the processing of one signal. Compared with using two detection components, the equipment cost and design difficulty are significantly reduced, and the reliability is significantly improved.

[0017] 3. Using commercially available tablet computers reduces the difficulty and cost of equipment development and system integration.

[0018] 4. Wireless communication is adopted between the detection device and the tablet computer, which reduces the number of accessories such as connecting wires and is more convenient to use.

[0019] 5. The maximum size of the detection device of this detection system is ≯φ200mm×450mm, and the maximum weight is ≯6kg; the maximum weight of the entire system is ≯8kg. It is easy to use by hand or carry in a backpack. After simple modification, it can also be used on vehicles such as drones, robot cars, and robot dogs, greatly expanding the scope of application of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the detection system of the present invention (handheld front).

[0021] Figure 2 This is a handheld side schematic diagram of the detection system of the present invention.

[0022] Figure 3 for Figure 1 Schematic diagram of the AA section.

[0023] Figure 4 This is a schematic diagram of the placement of the detection system of the present invention when carried in a backpack.

[0024] Among them: 1. Detection device, 2. Tablet computer, 3. Bracket, 4. Handle, 5. Wireless communication antenna, 6. Waterproof aviation connector, 7. Adapter (tablet), 8. Foam material, 9. Backpack, 10. Adapter (detection device), 11. Polyethylene moderator, 12. Rubber sleeve, 13. NaIL crystal, 14. Photomultiplier tube, 15. Photomultiplier tube socket and front-end electronics, 16. Back-end electronics, 17. Battery compartment and lithium battery pack, 18. Housing. DETAILED DESCRIPTION

[0025] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] It should be noted that when an element is referred to as being “mounted on” another element, it may be directly on the other element or there may be an element located in between.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] like Figure 1 、 Figure 2 As shown, an embodiment of the present invention provides a portable neutron gamma detection system based on NaIL crystal, including a detection device 1, a tablet computer 2, and optional accessories such as a bracket 3, a handle 4, a backpack 9, an adapter (tablet) 7, and an adapter (detection device) 10.

[0029] like Figure 3As shown, the detection device consists of a housing 18, a polyethylene moderator 11, a NaIL crystal 13, a photomultiplier tube 14, a photomultiplier tube base and a front-end electronic part 15, a rubber sleeve 12, a back-end electronic part 16, a battery compartment and a lithium battery pack 17, a wireless communication antenna 5, a waterproof aviation connector 6, etc.

[0030] The housing 18 of the detection device 1 is made of aluminum alloy, which has good mechanical properties, waterproof properties, electromagnetic shielding properties and is light in weight. The polyethylene moderator 11 is 5 cm or 7 cm thick and slows down the high energy neutrons into thermal neutrons. In addition to the elastic and inelastic scattering interactions of neutrons that deposit energy in the NaIL crystal 13 to make it emit light, some thermal neutrons can also generate 6 Li(n,α) 3 The H reaction produces alpha particles and tritium nuclei, which deposit 2.051 MeV and 2.735 MeV of energy, respectively, causing them to emit light. Gamma rays deposit energy in the NaIL crystal 13 through the photoelectric effect, Compton effect, and electron pair effect, causing it to emit light. 6 Li(n,α) 3 The decay time of the luminescence of α particles and tritium nuclei produced by H reaction in NaIL crystal 13 is significantly different from that of the luminescence produced by other processes.

[0031] The voltage divider module in the photomultiplier tube base and the front-end electronics part 15 provides the photomultiplier tube 14 with a working high voltage. The photomultiplier tube 14 can convert the optical signal into an electrical signal. The pre-current sensitive amplifier module in the photomultiplier tube base and the front-end electronics part 15 further amplifies the electrical signal. The obtained pulse waveform is related to the luminescence decay time of the scintillator.

[0032] The back-end electronics 16 provides operating voltage to the photomultiplier tube socket and front-end electronics 15 via connectors and shielded cables, while also acquiring the processed electrical signals. Back-end electronics 16 performs functions such as digital sampling of electrical signals, PSD calculation, energy calibration, and data storage. The data is then transmitted to the tablet computer 2 via the wireless communication antenna 5.

[0033] The battery compartment and lithium battery pack 17 are connected to the back-end electronics 16 via connectors and wires to provide operating power. The waterproof aviation connector is connected to the back-end electronics 16 via connectors and shielded cables. When the adapter (detection device) 10 is used, it can charge the detection device, and the detection device supports operation without battery adapter power supply.

[0034] The tablet computer 2 (with the required software pre-installed) plots a PSD-energy spectrum based on PSD and energy values, enabling neutron and gamma ray discrimination. The tablet computer 2 calculates and displays information such as the neutron count rate, gamma ray count rate, gamma ray energy spectrum, and gamma dose rate. Based on the gamma dose rate and GPS information, the tablet computer 2 plots a dose rate distribution map, identifies the type and location of radioactive sources, and implements audible and visual alarm functions.

[0035] The adapter (tablet) 7 is connected to the tablet computer 2 to charge the tablet computer 2. The tablet computer 2 supports working with power supplied by a battery-free adapter.

[0036] like Figure 4 As shown, when using a backpack to carry, the detection device 1, tablet computer 2, adapter, etc. are placed on the foam material 8 in a fixed position, and then the whole is placed in the backpack 9. At this time, the tablet computer can also be used alone by hand to observe the measurement results and sound and light alarm information.

[0037] The portable neutron gamma detection system based on NaIL crystal provided by this patent is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation of this patent. The description of the above embodiments is only used to help understand the method and core idea of ​​this patent. At the same time, for those skilled in the art, according to the idea of ​​this patent, there will be changes in the specific implementation and application scope. In summary, the content of this specification is only an implementation of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention. It should not be understood as a limitation of this patent.

[0038] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A portable neutron gamma detection system based on NaIL crystal, characterized in that: The invention comprises a detection device, a tablet computer, a bracket and a handle. The bracket and the handle are installed on the detection device through multiple sets of fastening bolts and spring washers. The tablet computer is fixed on the bracket through a buckle. The detection device is composed of a shell, a polyethylene moderator, a NaIL crystal, a photomultiplier tube, a photomultiplier tube holder and a front-end electronic part, a back-end electronic part, a battery compartment and a lithium battery pack, and a wireless communication antenna. The polyethylene moderator is installed on the shell through multiple sets of fastening bolts and spring washers. The NaIL crystal, the photomultiplier tube, the photomultiplier tube holder and the front-end electronic part are packaged as a whole. The NaIL crystal is completely inserted into the shell. The invention relates to a method for manufacturing a wireless communication system for transmitting the wireless communication signal to a user, wherein the wireless communication system comprises a photomultiplier tube seat and a front-end electronic part, wherein the photomultiplier tube seat and the front-end electronic part are installed on the outer shell through multiple sets of fastening bolts and spring washers, wherein the rear-end electronic part, the battery compartment and the lithium battery pack are installed on the outer shell through multiple sets of fastening bolts and spring washers, wherein the wireless communication antenna and the waterproof aviation connector are installed on the outer shell through nuts, spring washers and sealing rings, wherein the photomultiplier tube seat and the front-end electronic part are connected to the rear-end electronic part through connectors and shielded cables, wherein the rear-end electronic part is connected to the battery compartment and the lithium battery pack through connectors and wires, and wherein the rear-end electronic part is connected to the wireless communication antenna through connectors and shielded cables.

2. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: NaIL crystal is used as a detection element, and waveform discrimination and ray discrimination functions are realized based on the different luminescence characteristics of neutrons and gamma rays in the crystal.

3. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: Polyethylene is used as the neutron moderator material, and the thickness of the moderator is 5 cm to 7 cm.

4. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: The front-end electronics part uses only one current-sensitive preamplifier circuit, and the back-end electronics part uses only one digital sampling circuit.

5. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: The NaIL crystal, the photomultiplier tube, the photomultiplier tube base and the front-end electronic part are packaged as a whole and covered with a rubber sleeve for vibration reduction.

6. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: The detection device is connected to the adapter using a waterproof aviation connector to improve the environmental adaptability of the device, and the back-end electronic part is connected to the waterproof aviation connector through a connector and a shielded cable.

7. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: The detection device and the tablet computer communicate wirelessly via WIFI and Bluetooth.

8. The portable neutron gamma detection system based on NaIL crystal according to claim 1, characterized in that: The tablet computer is equipped with a touch screen, a speaker, multiple I / O interfaces, multiple function buttons, a large-capacity polymer lithium-ion battery, an adapter, WIFI, Bluetooth, 4G communication functions, a GPS module, and a Beidou module. The required software is pre-installed to achieve the following functions: drawing PSD-energy spectrum, neutron and gamma ray identification, calculating and displaying neutron count rate, gamma ray count rate, gamma ray energy spectrum, gamma dose rate information, drawing dose rate distribution diagram, distinguishing the type and location of radiation sources, and sound and light alarms.

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