阅读说明：本技术 一种便携式核放射性物质检测系统及检测方法 (Portable nuclear radioactive substance detection system and detection method ) 是由 李岩 赵弘韬 赵孝文 李钢 杨斌 杨仲秋 王强 于 2019-11-21 设计创作，主要内容包括：一种便携式核放射性物质检测系统及检测方法属于核检测技术领域；手持设备由于使用者本身的操作局限性,核安保不全面；本系统包括集成高压模块依次与闪烁探测器、脉冲放大器、甄别成形模块和微处理器连接,微处理器分别与计数/计量显示模块、报警灯和电量显示模块连接；电源管理芯片、集成高压模块、脉冲放大器、甄别成形模块、微处理器、锂电池、闪烁探测器安装在外套筒内,报警灯安装在外套筒上端,计数/计量显示模块和电量显示模块安装在外套筒的前后两侧上部,外套筒的下端通过连接环与底座连接；本系统能与隔离带栏杆组成检测通道,满足核安保要求；本方法通过本系统相结合进行放射性物质检测,对出入人员及设备进行实时在线检测方法。(A portable nuclear radioactive substance detection system and a detection method belong to the technical field of nuclear detection; the handheld device is not comprehensive in security and protection due to the operation limitation of a user; the system comprises an integrated high-voltage module, a scintillation detector, a pulse amplifier, a discrimination forming module and a microprocessor, wherein the integrated high-voltage module is sequentially connected with the scintillation detector, the pulse amplifier, the discrimination forming module and the microprocessor, and the microprocessor is respectively connected with a counting/metering display module, an alarm lamp and an electric quantity display module; the power supply management chip, the integrated high-voltage module, the pulse amplifier, the screening and forming module, the microprocessor, the lithium battery and the scintillation detector are arranged in the outer sleeve, the alarm lamp is arranged at the upper end of the outer sleeve, the counting/metering display module and the electric quantity display module are arranged at the upper parts of the front side and the rear side of the outer sleeve, and the lower end of the outer sleeve is connected with the base through a connecting ring; the system can form a detection channel with the isolation belt handrail, and meets the requirement of nuclear security; the method is a real-time online detection method for personnel and equipment in and out through radioactive substance detection by the combination of the system.)

1. A portable nuclear radioactive substance detection system is characterized by comprising a lithium battery (1), a power supply management chip (2), an integrated high-voltage module (3), a scintillation detector (4), a pulse amplifier (5), a screening and forming module (6), a microprocessor (7), a counting/metering display module (8), an alarm lamp (9) and an electric quantity display module (10); the output end of the lithium battery (1) respectively provides a +12V power supply for the integrated high-voltage module (3), a +12V power supply and a-12V power supply for the pulse amplifier (5), a +5V power supply for the screening and forming module (6) and a +3.3V power supply for the microprocessor (7) through the power management chip (2); the output end of the integrated high-voltage module (3) is sequentially connected with a scintillation detector (4), a pulse amplifier (5), a screening and forming module (6) and a microprocessor (7), and the output end of the microprocessor (7) is respectively connected with a counting/metering display module (8), an alarm lamp (9) and an electric quantity display module (10);

the power management chip (2), the integrated high-voltage module (3), the pulse amplifier (5), the screening and forming module (6) and the microprocessor (7) are all arranged on a circuit board, the lithium battery (1), the scintillation detector (4) and the circuit board are arranged in an outer sleeve (11), the alarm lamp (9) is arranged at the upper end of the outer sleeve (11), the counting/metering display module (8) and the electric quantity display module (10) are arranged on the upper parts of the front side and the rear side of the outer sleeve (1), the lower end of the outer sleeve (11) is connected with a base (13) through a connecting ring (12), a communication port socket, a power switch, a battery charging socket and an antenna socket are arranged on the base (13), and the communication port socket, the power switch, the battery charging socket and the antenna socket are all connected with the microprocessor (7);

the scintillation detector (4) comprises a sodium iodide scintillator (41) and two photomultiplier tubes (42), the sodium iodide scintillator (41) being mounted between the two photomultiplier tubes (42); the photomultiplier tube (42) is a glass vacuum device including a photocathode, dynode and anode.

2. A portable nuclear radioactive substance detection system according to claim 1, wherein the lithium battery (1), the scintillation detector (4) and the circuit board are mounted together, the elongated scintillator of the scintillation detector (4) is mounted uppermost, the circuit board is mounted in a middle position, and the lithium battery (1) is mounted lowermost.

3. A portable nuclear radioactive substance detection system according to claim 1, wherein the outer sleeve (11) is of a vertical cylindrical configuration with an outer diameter of 80mm and a height of 1200 mm.

4. A portable nuclear radioactive material detection system according to claim 1, further comprising a chassis (14), the chassis (14) being fixedly mounted below the base (13) for erecting and stabilizing the base (13).

5. A detection method implemented on the basis of the portable nuclear radioactive substance detection system of claims 1 to 4, comprising the steps of:

step a, turning on a power switch, and supplying power to each module by a lithium battery (1);

b, detecting gamma rays by a scintillation detector (4), and outputting a negative pulse signal;

c, because the amplitude of the negative pulse signal is small, performing reverse amplification through a pulse amplifier (5);

d, shaping the amplified positive pulse signals into positive pulse signals with uniform amplitudes through a discrimination forming module (6);

e, the regular positive pulse signals are subjected to data processing, operation and judgment through a microprocessor (7), parameters are set and modified through the microprocessor (7), and when the count or the dosage exceeds a set threshold value, an alarm lamp (9) gives an alarm; when the count exceeds the dosage shifting boundary value, the calibration constant is automatically changed for operation and is displayed through a counting/metering display module (8); the residual capacity of the lithium battery (1) is displayed in real time through the capacity display module (10).

6. The portable nuclear radioactive substance detection method according to claim 5, wherein the method of detecting gamma rays by the scintillation detector (4) in the step b includes ionizing and exciting the sodium iodide scintillator (41) by gamma rays incident on the sodium iodide scintillator (41), and energy is lost by ionizing radiation; when excited atoms or molecules are de-excited, fluorescence is emitted, namely photons, and the energy absorbed by the sodium iodide scintillator (41) is partially converted into light energy; the photons are collected on the photocathode of the photomultiplier tube (42) through the optical glass window; the collected photons generate photoelectrons on the photocathode through a photoelectric effect; the photoelectrons are multiplied in sequence by a dynode and an increasing accelerating electric field; the multiplied number of electrons is eventually collected by the anode and forms an observable negative polarity pulsed electrical signal on the external load resistance.

7. A portable nuclear radioactive substance detection method according to claim 6, wherein the alarm by the alarm lamp (9) includes assuming a local natural radioactivity maximum background count rate of n_bAlarm threshold n for count rate_yCalculated as follows:

calculating the alarm threshold of equivalent dose rate according to the above formula

Technical Field

The invention belongs to the technical field of nuclear detection, and particularly relates to a portable nuclear radioactive substance detection system and a detection method.

Background

In a typical terrorist act, the survivors will be rescued and treated and the non-victims will not be at risk after the terrorist act. An attack may lead to a psychological shock or threat, but this effect is limited in time and space; dust generated by terrorist acts can be diffused, fire disasters and building damages can also bring danger, but the substances have no inherent danger; the cleaning work is limited to a certain range, the immediate place where the event occurs is safe, and the legal investigation can be carried out by adopting the common method. Such events do not prevent the relevant authorities from providing normal government services.

When the radioactive substance scattering device explodes (nuclear dirty bomb), the situation is different, the radioactive substance pollutes the trauma, so that the casualty is very difficult to treat, and the casualty can still have the possibility of being survived and free from the trauma immediately after the attack; shrapnel and other generally harmless materials generated by an explosion will be contaminated by radioactive substances, and the affected area will be much larger than the incident site. Long-term health effects that cannot be seen visually and radiation threats that cannot be judged with certainty will cause the public to panic and eventually disturb social order.

Two typical approaches to nuclear and radiation terrorist threats: simple nuclear devices and radioactive distribution devices (nuclear dirty bombs or RDDs). Today only the former soviet union has thousands of tons of weapon grade nuclear material, plus tens of thousands of radioactive substances and a large number of orphan sources. Even if a very small part of such a radioactive substance falls into the hands of terrorists, it will cause an unexpected damage to the human society.

Strengthening nuclear security is the most effective method for preventing nuclear accidents and nuclear terrorism. The nuclear security includes 3 basic elements, detection, delay and response. Wherein, the detection refers to a technical means of detecting the occurrence of a nuclear security event and sending an alarm; delay refers to a technical means that can delay or prevent an adversary from performing an action; the response is a quick action taken to terminate the development of a nuclear security event. The detection among the 3 elements is most important, the occurrence of nuclear-related accidents can be avoided only by finding radioactive substances, and the detection of the radioactive substances is the basis for the development of nuclear security work.

At present, only in the occasions with extremely high security level (such as important leaders or meetings participated by foreign guests) security personnel can hold the radiation dosage instrument by hand to check the nuclear security, but the handheld equipment cannot meet the real nuclear security requirement due to the operation limitation of users.

Disclosure of Invention

The system adopts a column structure design integrating a scintillation detector and a power supply lithium battery, can form a detection channel with an isolation belt rail, can be quickly deployed at an entrance and an exit of important places such as nuclear facilities, frontier ports, subways, airports, large conference activities and the like for use, and truly meets the requirement of nuclear security; the method is a real-time online detection method for detecting whether people and equipment in and out contain radioactivity by detecting radioactive substances in a mode of combining the system.

The technical scheme of the invention is as follows:

technical scheme one

A portable nuclear radioactive substance detection system comprises a lithium battery, a power supply management chip, an integrated high-voltage module, a scintillation detector, a pulse amplifier, a discrimination forming module, a microprocessor, a counting/metering display module, an alarm lamp and an electric quantity display module; the output end of the lithium battery respectively provides a +12V power supply for the integrated high-voltage module, a +12V power supply and a-12V power supply for the pulse amplifier, a +5V power supply for the discrimination forming module and a +3.3V power supply for the microprocessor through the power supply management chip; the output end of the integrated high-voltage module is sequentially connected with the scintillation detector, the pulse amplifier, the screening and forming module and the microprocessor, and the output end of the microprocessor is respectively connected with the counting/metering display module, the alarm lamp and the electric quantity display module;

the power management chip, the integrated high-voltage module, the pulse amplifier, the screening and forming module and the microprocessor are all arranged on a circuit board, the lithium battery, the scintillation detector and the circuit board are arranged in the outer sleeve, the alarm lamp is arranged at the upper end of the outer sleeve, the counting/metering display module and the electric quantity display module are arranged at the upper parts of the front side and the rear side of the outer sleeve, the lower end of the outer sleeve is connected with the base through a connecting ring, the base is provided with a communication port socket, a power switch, a battery charging socket and an antenna socket, and the communication port socket, the power switch, the battery charging socket and the antenna socket are all connected with;

the scintillation detector comprises a sodium iodide scintillator and two photomultiplier tubes, and the sodium iodide scintillator is arranged between the two photomultiplier tubes; the photomultiplier is a glass vacuum device that includes a photocathode, dynode, and anode.

Further, lithium cell, scintillation detector and circuit board are installed together, the extension scintillator of scintillation detector is installed in the top, and the circuit board is installed in the intermediate position, and the lithium cell is installed in the below.

Further, the outer sleeve is of a vertical cylindrical structure, the outer diameter of the outer sleeve is 80mm, and the height of the outer sleeve is 1200 mm.

Further, still include the chassis, the chassis fixed mounting is in the base below for make the base upright and more stable.

Technical scheme two

The detection method implemented by the portable nuclear radioactive substance detection system based on the technical scheme includes the following steps:

step a, turning on a power switch, and supplying power to each module by a lithium battery;

b, detecting gamma rays by a scintillation detector, and outputting a negative pulse signal;

c, because the amplitude of the negative pulse signal is small, performing inverse amplification through a pulse amplifier;

d, shaping the amplified positive pulse signals into positive pulse signals with uniform amplitudes through a discrimination forming module;

e, the regular positive pulse signals are subjected to data processing, operation and judgment through a microprocessor, parameters are set and modified through the microprocessor, and when the count or the dosage exceeds a set threshold value, an alarm lamp gives an alarm; when the count exceeds the dosage shifting boundary value, the calibration constant is automatically changed for operation and is displayed through the counting/metering display module; and displaying the residual electric quantity of the lithium battery in real time through the electric quantity display module.

Further, the method for detecting gamma rays by the scintillation detector in the step b comprises ionizing and exciting the sodium iodide scintillator by the gamma rays incident on the sodium iodide scintillator, and losing energy by ionizing radiation; when excited atoms or molecules are de-excited, fluorescence, namely photons, is emitted, and the energy absorbed by the sodium iodide scintillator is converted into light energy; the photons are collected on a photocathode of a photomultiplier through an optical glass window; the collected photons generate photoelectrons on the photocathode through a photoelectric effect; the photoelectrons are multiplied in sequence by a dynode and an increasing accelerating electric field; the multiplied number of electrons is eventually collected by the anode and forms an observable negative polarity pulsed electrical signal on the external load resistance.

Further, the method of alarming by the alarm lamp includes assuming a local natural radioactivity maximum background count rate of n_bAlarm threshold n for count rate_yCalculated as follows:

calculating the alarm threshold of equivalent dose rate according to the above formula

When measured and displayed equivalent dose rate

The alarm is not started, which indicates that no radioactive substance exists; when in use

The instrument gives out sound and light alarm to indicate the existence of radioactive substances, and a response mechanism needs to be started.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a portable nuclear radioactive substance detection system and a detection method, the system adopts a column structure design integrating a scintillation detector and a power supply lithium battery, can form a detection channel with an isolation strip rail, can be rapidly deployed at an entrance and an exit of important places such as nuclear facilities, frontier ports, subways, airports, large conference activities and the like, has the functions of portability and rapid deployment, and meets the real requirement of nuclear security; the system can quickly respond to weak radioactive substances and control the occurrence of nuclear-related accidents to the maximum extent;

the method is based on the nuclear physics measurement principle, adopts a mode of combining a double-path photomultiplier sodium iodide scintillator radiation detector with multi-path pulse signal acquisition to detect radioactive substances, and carries out real-time online detection on whether people and equipment in and out contain radioactivity.

Drawings

FIG. 1 is a block diagram of the electrical components of the present invention;

FIG. 2 is a view showing the structure of the outer appearance of the present invention;

fig. 3 is a block diagram of a scintillation detector.

In the figure; the system comprises a lithium battery 1, a power management chip 2, an integrated high-voltage module 3, a scintillation detector 4, a sodium iodide scintillator 41, a photomultiplier 42, a pulse amplifier 5, a discriminator forming module 6, a microprocessor 7, a counting/metering display module 8, an alarm lamp 9, an electric quantity display module 10, an outer sleeve 11, a connecting ring 12, a base 13 and a base plate 14.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.