Radiation detection device

Abstract

The utility model provides a radiation detection device, and belongs to the field of security and protection. The radiation detection device comprises a shell, a radiation detector, a signal processing module and a communication module which are sequentially connected are arranged in the shell, and the communication module is connected with a computer. The radiation detector comprises a gamma ray detector and a neutron detector, and the gamma ray detector and the neutron detector are both connected with the signal processing module. According to the utility model, gamma rays and neutrons in the surrounding environment are detected to detect radioactive substances, and alarm information is output through signal processing and transmission; the device is small in size, can be integrated in the existing security inspection equipment, and achieves the purposes of detecting radioactive substances of objects carried by inspection personnel and achieving management and control according to a detection result.

Description

Technical Field

[0001] The utility model belongs to the field of security and is a device for performing radiation monitoring on articles carried by inspected personnel, in particular to a radiation detection device. Background Art

[0002] With the increasing types of radiation sources, such as nuclear materials, medical radioactive materials, industrial radioactive materials, etc., the radioactive detection technology in security inspection has received more and more attention and importance. In particular, radioactive items involve a wide range of areas and are highly concealed, requiring professional detection equipment for detection. In key security locations such as border defense and customs or nuclear-related units, door-type / channel-type monitoring equipment is usually used to effectively detect and eliminate possible radioactive substances to ensure public health and safety.

[0003] Chinese patent publication CN209513669U discloses a radioactive security inspection device and system, including a controller and gamma ray / neutron detectors, cameras, laser rangefinders and other equipment connected thereto, which are used to detect radioactive sources in large places and their location information; Chinese patent publication CN115469351A discloses a radioactive positioning detection method and security inspection door, which can detect not only the presence of radioactive materials but also the location of radioactive materials by configuring multiple radioactive material detection detectors on the columns and beams of the security inspection door. Chinese patent publication CN109061708A discloses a portal radioactive monitoring and identification system, which can simultaneously monitor radioactive materials emitting neutron rays and gamma rays by arranging gamma detectors, neutron detectors, nuclide identification detectors, alarm devices, etc. on the portal frame, and can identify nuclides, and the nuclide identification detector can be switched between fixed detection and handheld detection according to on-site needs.

[0004] For other key public safety areas, such as airports, passenger boarding security is very strict. Passengers' checked or carry-on luggage will go through X-ray security and radiation detection to prevent passengers from bringing inflammable and explosive materials, radioactive materials, controlled knives and other dangerous items on board. As a key public safety area, the terminal building is particularly important for the security inspection of people and items at its entrance. In addition to explosion-proof detection, technical means have not yet been applied to prevent radioactive materials from being illegally brought in, which is a huge threat to public safety. Airport management urgently needs fast and effective detection methods to screen dangerous people and items. Similarly, ordinary stations, docks and major event venues also need corresponding radiation detection technology to better protect public safety and maintain social stability.

[0005] The existing portal / channel monitoring equipment is large in size. On the one hand, it is not easy to deploy in existing terminals and stations. On the other hand, it is difficult to control the inspected personnel using this type of equipment alone, and a large number of manpower must be added on site to handle it. Utility Model Content

[0006] The purpose of the utility model is to solve the problems existing in the above-mentioned prior art and to provide a radiation detection device which is small in size and can be integrated into existing security inspection equipment to detect radioactive objects in items carried by inspected persons and achieve the purpose of management and control based on the detection results.

[0007] The utility model is realized by the following technical solutions:

[0008] The utility model provides a radiation detection device, comprising a housing, wherein a radiation detector, a signal processing module and a communication module connected in sequence are arranged in the housing;

[0009] The communication module is connected to the computer.

[0010] The further improvement of the utility model is:

[0011] The radiation detector comprises a gamma ray detector and a neutron detector, and both the gamma ray detector and the neutron detector are connected to the signal processing module.

[0012] The further improvement of the utility model is:

[0013] The circuit structure of the signal processing module includes a first analog buffer and a second analog buffer, the first analog buffer is electrically connected to the first analog-to-digital converter, the second analog buffer is electrically connected to the second analog-to-digital converter, and the first analog-to-digital converter and the second analog-to-digital converter are both electrically connected to a field programmable gate array chip FPGA.

[0014] The further improvement of the utility model is:

[0015] The first analog buffer is connected to the gamma-ray detector.

[0016] The further improvement of the utility model is:

[0017] The second analog buffer is connected to the neutron detector.

[0018] The further improvement of the utility model is:

[0019] The radiation detection device also includes a power supply module, which is respectively connected to the gamma ray detector, the neutron detector, the signal processing module and the communication module.

[0020] The further improvement of the utility model is:

[0021] The gamma-ray detector is a plastic scintillator detector.

[0022] The further improvement of the utility model is:

[0023] The neutron detector is a helium-3 neutron detector.

[0024] The further improvement of the utility model is:

[0025] Two holes are provided on one side wall of the shell, which are respectively used to lead out a signal line connected to the communication module and a power line connected to the power module.

[0026] Compared with the prior art, the beneficial effects of the utility model are:

[0027] The utility model provides a radiation detection device, which detects radioactive materials by detecting gamma rays and neutrons in the surrounding environment, and outputs alarm information through signal processing and transmission. The device is small in size and can be integrated into existing security inspection equipment to detect radioactive materials in items carried by inspected personnel, and achieve the purpose of control based on the detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a radiation detection device of the utility model;

[0029] Figure 2 It is a circuit diagram of a radiation detection device.

[0030] In the figure, 101 is a power module, 102 is a plastic scintillator detector, 103 is a helium-3 neutron detector, 104 is a signal processing module, and 105 is a communication module. DETAILED DESCRIPTION

[0031] The utility model is further described in detail below in conjunction with the accompanying drawings:

[0032] like Figure 1 As shown, the utility model provides a radiation detection device, two radiation detection devices are arranged opposite to each other, the radiation detection device includes a shell, and a radiation detector, a signal processing module 104 and a communication module 105 connected in sequence are arranged in the shell, and the communication module 105 is connected to a computer; the shell is a rectangular parallelepiped with an outer dimension of 20 cm×30 cm×70 cm, and a plurality of M6 welding threaded holes are arranged at the bottom of the shell for installing the radiation detection device on other components, and two handles are installed on the top of the shell to facilitate the transportation and installation of the radiation detection device.

[0033] The radiation detector comprises a gamma ray detector and a neutron detector, and the gamma ray detector and the neutron detector are respectively connected to the signal processing module through cables.

[0034] The gamma-ray detector is preferably a plastic scintillator detector 102 with stable performance, radiation resistance, reliable response and low price for the detection of gamma-rays. The plastic scintillator detector 102 is mainly composed of a plastic scintillator and a photomultiplier tube. The plastic scintillator interacts with the gamma-ray to generate energy, which will excite fluorescent molecules and generate light signals, which are converted into electrical signals by the photomultiplier tube and can be measured, analyzed and processed. The plastic scintillator detector 102 used in the utility model is a prior art detector and will not be described in detail here.

[0035] The neutron detector is preferably a helium-3 neutron detector 103 with high detection efficiency, stable performance and non-toxicity for neutron detection. The helium-3 neutron detector 103 is mainly composed of a helium-3 proportional counter tube and a polyethylene moderator. The helium-3 proportional counter tube contains 3He gas. The incident neutrons react with 3He atoms to generate two kinds of charged particles, protons and tritium nuclei, and ionize the working gas. Neutron detection is achieved by measuring the current signal. It has a good reaction efficiency for slow neutrons. In order to improve its detection efficiency for fast neutrons, a polyethylene moderator layer of a certain thickness is added outside the detector. The helium-3 neutron detector 103 used in the utility model is a prior art detector and will not be described in detail here.

[0036] The signal processing module 104 is used to receive the electrical signals sent by the gamma ray detector and the neutron detector and perform analog signal processing to obtain the counting rates of gamma rays and neutrons respectively.

[0037] like Figure 2 As shown, the circuit structure of the signal processing module 104 includes a first analog buffer and a second analog buffer, the first analog buffer is electrically connected to the first analog-to-digital converter, the second analog buffer is electrically connected to the second analog-to-digital converter, and the first analog-to-digital converter and the second analog-to-digital converter are both electrically connected to the field programmable gate array chip FPGA. The plastic scintillator detector and the helium-3 neutron detector send the detected electrical signals to the signal processing module, and the electrical signals are sequentially buffered, amplified, and converted into digital signals, and the digital signals are sent to the field programmable gate array chip FPGA for data processing to obtain the counting rates of gamma rays and neutrons, respectively.

[0038] Preferably, the first analog-to-digital converter adopts a converter chip model AD9434, the second analog-to-digital converter adopts a converter chip model LTC2141, and the field programmable gate array chip FPGA is preferably a Zynq-7020.

[0039] The signal processing module 104 sends the gamma ray and neutron counting rates to the communication module 105, which performs level conversion, packaging and other operations on the data according to the communication protocol, transmits the data by wire through a serial port, a network port, etc., or transmits the data wirelessly to a computer for storage and display, and issues an alarm message according to a set threshold. The communication module 105 adopts an existing technology product and is not described in detail here.

[0040] The radiation detection device further includes a power module 101, which is respectively connected to the gamma ray detector, the neutron detection detector, the signal processing module 104 and the communication module 105, and is used to supply power to the gamma ray detector, the neutron detection detector, the signal processing module 104 and the communication module 105. The power module 101 uses a power chip, preferably a 4644Y model.

[0041] Two holes are provided on one side wall of the housing, which are used to lead out a signal line connected to the communication module 105 and a power line connected to the power module 101, respectively, wherein one end of the signal line is connected to the computer.

[0042] The technical indicators of the radiation detection device are set to meet the requirements of the pedestrian monitoring system in GB / T 24246-2009 Radioactive Material and Special Nuclear Material Monitoring System, and a double-sided detection column model is selected, that is, a radiation detection device is placed on each side of the pedestrian passage, with a distance of 1m, and the radiation source is placed between the two radiation detection devices. The specific technical indicators are: 137 Cs standard source, static detection efficiency of gamma rays is not less than 800s -1 / MBq; use 252 Cf standard neutron source, neutron static detection efficiency is not less than 100s -1 / 12000Bq.

[0043] In order to achieve the above technical indicators, the sizes of the plastic scintillator, helium-3 proportional counter tube and moderator layer are simulated and designed. According to the national standard test requirements, a radiation detection device is configured on each side of the detection area, and each detection device includes a plastic scintillator detector and a helium-3 neutron detector. After simulation calculation, the size of the plastic scintillator is 5cm×10cm×50cm, and the volume is 2.5L; the diameter of the helium-3 proportional counter tube is 5cm, and the outside is wrapped with a 4.5cm thick polyethylene moderation layer to increase the detection efficiency. Through simulation, under the condition of one atmosphere, the detection efficiency of the two helium-3 proportional counter tubes is 461c / s / 100000n / s when they are 0.5 meters away from the radiation source, and the detection efficiency of the plastic scintillator is 1101c / s / 100000n / s, and the sum of the two meets the index requirements.

[0044] According to the detailed dimensions of the detector simulation design, the plastic scintillator detector and helium-3 neutron detector are customized, and the circuit part is designed and implemented, including the signal processing module and the communication module. At the same time, the shell of the radiation detection device is designed and customized to complete two prototypes of the entire device.

[0045] Two radiation detection device prototypes were sent to the China National Institute of Metrology (Beijing) for testing. Gamma ray detection calibration and neutron detection calibration were carried out in accordance with the "JJF 1266-2010 Calibration Specifications for Pedestrian and Baggage Radioactive Monitoring Devices" (covering the "GB / T 24246-2009 Radioactive Material and Special Nuclear Material Monitoring System") to test the overall performance indicators of the device.

[0046] The test calibration was carried out in an environment with a temperature of 25°C and a humidity of 53% RH. The detector was preheated for 30 minutes and then 10 groups of count rates (s) were randomly read without interference from radiation sources. -1 ), calculate the average value as the background count rate 1596.5s -1 , and remove the background effect in the final calibration data. When calibrating gamma-ray detection, a standard radiation source is used, and the radiation detection devices are located 1 meter away from each other on both sides of the radiation source. The count rate is read through the background computer and corresponding software. The calibration results are shown in Table 1. It can be seen that the two radiation detection devices are 137 The sensitivity of Cs is 2.28×10 pulses / s / kBq, equivalent to 2280s -1 / MBq, meeting and exceeding index requirements.

[0047] Table 1 Gamma-ray detection calibration results

[0048]

[0049] During the neutron detection calibration, a 241Am-Be neutron source was used. The radiation detection devices were located 0.5 meters away from each other on both sides of the radiation source. The count rate was read through the background computer and the corresponding software. The calibration results are shown in Table 2. It can be seen that the sensitivity of the two radiation detection devices to neutrons is 43.1 c·s -1 2000n -1 ·s -1 , equivalent to 258s -1 / 12000Bq, meeting and exceeding the index requirements.

[0050] Table 2 Neutron detection calibration results

[0051]

[0052] According to the test results of the Institute of Metrology, the overall response time is guaranteed to be within 1s, that is, when the radiation source appears within a certain range of this radiation detection device, it can respond to it and transmit the counting rate to the background computer in real time to make a judgment and send out an alarm signal.

[0053] As an embodiment of the utility model, a radiation detection device is designed according to the above indicators, and a plastic scintillator detector, a helium-3 neutron detector, a power module, a signal processing module and a communication module are customized, wherein the signal processing module and the communication module are implemented on the same circuit board.

[0054] At the same time, in order to ensure that sensitive components are protected from potential physical collisions or external damage, a metal shell of the radiation detection device is designed. The shell is made of sheet metal and is divided into two parts: the top plate and the bottom plate, which are fixed by screws. The shell is in the shape of a rectangular parallelepiped with an outer dimension of 20 cm × 30 cm × 70 cm. Inside the shell, the plastic scintillator detector and the helium-3 neutron detector are fixed side by side at the bottom. The power module, signal processing module and communication module are fixed above the plastic scintillator detector. Two holes are left at the front end of the shell for leading out related signal lines and power lines, and a plastic wiring cover is added for dust prevention. Multiple M6 welding threaded holes are reserved at the bottom of the shell for mounting the radiation detection device on other components. The entire radiation detection device weighs about 22 kg, and two handles are installed on the top of the shell to facilitate the transportation and installation of the radiation detection device.

[0055] The radiation detection devices in this embodiment are installed in pairs inside the security gate, one on each of the left and right islands of the gate, for radiation detection of carry-on items of persons passing through the security gate. When the inspected person arrives in front of the security gate, the radiation detection can be triggered by face scanning, card swiping, document scanning, etc. The radiation detection devices on both sides detect gamma rays and neutrons, and can have the following two working modes: 1) The radiation detection device processes data and sends the count rate to the controller inside the gate. After synthesis, calculation and analysis, the controller compares the count with the threshold and controls the opening and closing of the gate according to the comparison result; 2) The radiation detection device processes and calculates data, compares the count with the threshold, and sends a normal / abnormal alarm signal to the controller inside the gate. The controller controls the opening and closing of the gate according to the received information.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0058] The above technical solution is only one implementation method of the utility model. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the utility model, and it is not limited to the technical solution described in the above specific embodiments of the utility model. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A radiation detection device, characterized in that: Two radiation detection devices are arranged opposite to each other, and the radiation detection device comprises a housing, and a radiation detector, a signal processing module and a communication module are arranged in the housing in sequence; The communication module is connected to the computer; The shell is a rectangular parallelepiped with an outer dimension of 20 cm×30 cm×70 cm. A plurality of M6 welding threaded holes are arranged at the bottom of the shell, and two handles are installed at the top of the shell.

2. The radiation detection device according to claim 1, characterized in that: The radiation detector comprises a gamma ray detector and a neutron detector, and both the gamma ray detector and the neutron detector are connected to the signal processing module.

3. The radiation detection device according to claim 2, characterized in that: The circuit structure of the signal processing module includes a first analog buffer and a second analog buffer, the first analog buffer is electrically connected to the first analog-to-digital converter, the second analog buffer is electrically connected to the second analog-to-digital converter, and the first analog-to-digital converter and the second analog-to-digital converter are both electrically connected to a field programmable gate array chip FPGA.

4. The radiation detection device according to claim 3, characterized in that: The first analog buffer is connected to the gamma-ray detector.

5. The radiation detection device according to claim 3, characterized in that: The second analog buffer is connected to the neutron detector.

6. The radiation detection device according to any one of claims 2 to 5, characterized in that: The radiation detection device also includes a power supply module, which is respectively connected to the gamma ray detector, the neutron detector, the signal processing module and the communication module.

7. The radiation detection device according to claim 6, characterized in that: The gamma-ray detector is a plastic scintillator detector.

8. The radiation detection device according to claim 6, characterized in that: The neutron detector is a helium-3 neutron detector.

9. The radiation detection device according to claim 6, characterized in that: Two holes are provided on one side wall of the shell, which are respectively used to lead out a signal line connected to the communication module and a power line connected to the power module.

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