Scientific vision - look at leak detection radioactivity dose rate for security equipment

Japan`s nuclear leakage has become the focus of global attention. The [butterfly effect" caused by nuclear power accidents has caused the public`s fear of nuclear radiation to spread globally. The shadow of [talking about radiation discoloration" triggered by [talking about nuclear discoloration" has also been quiet. Shrouded in the hearts of people. While all sectors of the society are highly concerned about the impact of "nuclear radiation," the security industry is also conducting a lively discussion on the "leakage radiation dose rate" of X-ray security inspection equipment. With the increasing intensification of international terrorist activities, all governments have stepped up public safety precautions. X-ray security inspection equipment designed to detect dangerous goods and contraband concealed in baggage items, because of its intuitive imaging, can effectively highlight the display of tools, explosives, drugs and other contraband, at airports, customs, railways, subways Various types of public places have been widely used, and thus have increasingly entered the public eye. "Leakage ray dose rate" - as an important indicator of radiation and environmental safety, it is not only a simple value that reflects the level of ray leakage from X-ray safety inspection equipment, but also represents a public safety inspection equipment manufacturing company. Kind of respect and protection. Then, as the production company has the responsibility and obligation to reduce public concerns, is it necessary to blindly pursue the leak radiation dose rate as low as possible? In this regard, this article also focuses on the topic of [leakage radiation dose rate" that people are concerned about.

Question one: What is the leakage radiation dose rate?

Radiation safety indicators for X-rays typically include a single inspection dose and leaked radiation dose rate for the device.

In our country's national standard GB 15208.1-2005 "micro-dose X-ray safety inspection equipment Part 1: General technical requirements", the device's single inspection dose is defined as "the X-ray dose absorbed by one inspection of the object being inspected, single The dose unit for the examination is Gy, 1 Gy = 1 J/kg. Leakage radiation dose rate of the equipment refers to the radiation shielding protection that passes through the unit time. The unit of ionizing radiation intensity leaked to the outside of the equipment is expressed as air kerma energy rate, which is μGy/h.

The GB 15208.1-2005 radiation safety indicator for the micro-dose X-ray safety inspection equipment is: the single inspection dose of the equipment should not exceed 5μGy; at any position 5cm away from the outer surface of the equipment (including the inlet and outlet of the equipment), X The radiation exposure dose rate should be less than 5μGy/h, in line with the requirements of 3.1 in GB17060-1997.

If the X-ray safety inspection device complies with national safety standards, the human body can be irradiated with a dose of less than 5 μGy. We use the CT and X-ray values we usually know to explain: CT scanning dose standard is 35mGy (35000μGy), and the dose standard for X-ray fluoroscopy we often do on physical examination is 50mGy (50000μGy).

From the above data, it can be seen that the radiation dose value of the security inspection equipment can be said to be insignificant, and the irradiation time and distance are also the key factors that determine the body's absorbable dose. Unlike medical X-ray instruments, X-ray security devices in public places are safe and reliable without excessive worry. Even special populations such as pregnant women have little time near X-ray machines and take necessary distance protection. influences.

Question 2: What are the factors affecting the "leakage radiation dose rate" of X-ray safety inspection equipment?

The X-ray security inspection equipment guarantees the resolution and sharpness of the generated image, and the requirements on the radiation source and the tube voltage are certain. Therefore, the amount of radiation generated is also certain. To reduce the radiation leakage dose rate, it can only be achieved through shielding and shielding measures.

From a technical point of view, the screening protection adopted by security inspection equipment manufacturers refers to the use of substances with a high atomic number, commonly used lead or lead-containing substances, as a barrier to absorb unnecessary x-rays.

The radiation protection of general X-ray security inspection equipment mainly has two places:

The first is the lead curtain of the entrance and exit of the inspection channel. Its material is rubber or plastic with high lead content. Its lead equivalent is not less than 0.35mm thick lead plate. Has a strong X-ray protection, can effectively reduce the leakage of X-rays, to avoid X-ray radiation to the staff.
Another major area is the passage plate, which consists of steel plates and lead plates. The lead metal lattice structure of lead plate has a large number of lead atoms and a very dense atomic structure, and has strong X-ray protection and can be effective. Reduce X-ray leakage and reduce X-ray radiation to workers.

Therefore, the protective effect of the lead curtain and the channel plate has become an important factor in determining the "leakage radiation dose rate" of the security inspection equipment. In particular, the thickness of the lead plate in the channel plate has played a crucial role.

Question 3: Is the "leakage radiation dose rate" as small as possible?

As described in the previous section, the thickness of the lead plate in the channel plate is a key factor in determining the "leakage radiation dose rate." So, does it mean that in order to reduce the radiation dose rate of equipment, we must blindly increase the thickness of the lead plate?

In fact, taking this extreme is not a good thing. On the one hand, the use of too many lead plates will significantly increase the weight of the equipment. It will be extremely difficult to move and transport the equipment. On the other hand, as a heavy metal, lead will remain, accumulate, and migrate once it is abandoned into the environment or ecosystem. , causing great harm to the natural environment. Therefore, in the current era of advocating environmental protection, such an approach is bound to be undesirable.
Guangdong Andun Industrial Investment Co., Ltd. is such a national enterprise that vowed to take public safety as its own responsibility. With strong technical research and development capabilities and improved production processes, X-ray safety inspection equipment manufactured by Guangdong Andun has been tested by the Ministry of Public Security. Its [leakage radiation dose rate is ≤1 μGy/hour (5cm from the surface of the housing)". Far exceeded the national security standards and reached the international advanced level.

Adhering to the corporate vision of [Protecting Corporate Property and Safeguarding Public Safety", Guangdong AnDun has always adhered to the business philosophy of [Innovation, Enterprise Recruitment and Respect for the Country". Standardized operation strictly requires that each factory-installed security inspection device meet the standards of [leakage radiation dose rate ≤1 μGy/hour" that is detected by the Ministry of Public Security, and that certain manufacturers in the industry will not [exit machine" and [detection". "Mockup" spuriously treated differently. Relying on a strong after-sales service professional team, Guangdong Andun regularly conducts inspections on equipment that is already in operation every year. According to the person in charge of the after-sales service team of Guangdong Andun, the service team of Guangdong Andun will be equipped with hand-held equipment from 2011 onwards. Radiation detectors, and radiation detection as one of the important contents of inspection.

to sum up:

Therefore, as a manufacturer of X-ray security inspection equipment, in the endeavor to do well equipment radiation protection measures, and strive to reduce the radiation dose of equipment, but also have the responsibility to take into account and take into account the equipment may cause harm to the environment after being scrapped. Only by finding such a balance can it be a good enterprise that is qualified and socially responsible.

As people in public places will inevitably contact security inspection equipment, it needs to be clear: as long as the security inspection equipment is within the safety radiation standards prescribed by the State, it will have almost no impact on the human body! Even special groups such as pregnant women do not cause any harm to themselves as long as they pay attention and take the necessary distance protection.

As a buyer of X-ray security inspection equipment, there is no need to blindly pursue equipment. Leakage radiation dose rate is low and low, and some companies are advocating that the leakage radiation dose rate of equipment is even lower than the natural background level in the air. ! Therefore, after understanding the basic knowledge of "leakage radiation dose rate," I believe that everyone can use a scientific perspective to look at the problem and wisely identify the advantages and disadvantages of the equipment.