Tungsten Alloy Shield
mechanism of action
Tungsten alloy shielding cans have good shielding benefits for radioactive substances because of the high density of tungsten alloys. The study found that the high density of metal has a good shielding effect on radiation, and as the density of metal increases, the shielding of radiation is also better. Therefore, the tungsten alloy shield has a good shielding effect.
Material comparison
Lead and tungsten alloys are relatively denser among existing metals. Metal lead was used earlier, but some problems were exposed during long-term use. Lead itself and its compounds are toxic to various tissues of the human body. The way of poisoning can be inhaled its vapor or dust through the respiratory tract, and then the phagocytes in the respiratory tract quickly bring it to the blood; or it is absorbed through the digestive tract and enters the blood circulation to cause poisoning. Poisoned people generally have a history of exposure to lead and lead compounds. Oral 2-3 grams can cause poisoning, 50 grams can cause death. Relevant departments are vigorously researching lead substitutes and gradually eliminating the use of lead. In this context, tungsten is gradually being taken seriously. High specific gravity tungsten alloys are generally used in the production of shielding products. Tungsten alloys are not only dense but also non-toxic and harmless.
Compared with tungsten alloys, tungsten alloys and lead materials show more environmentally friendly properties. Tungsten itself is neither toxic nor radioactive. And tungsten alloy is easy to process, and tungsten reserves are abundant.
Classification
Syringe shield
The tungsten alloy syringe shield is made of tungsten alloy as a raw material and is a medical device that plays a protective role in medical injection of radiopharmaceuticals. Tungsten alloy syringe shield is the shielding effect of high-density tungsten alloy on radioactive particles. The density of tungsten alloy can reach 16.5-19.0g/cm3, which has a good shielding effect on radioactive particles.
Tungsten alloy syringe shields are often used as injection instruments for isotope tracing to monitor the efficacy of drugs in medicine. Using the nuclear physical properties of radioisotopes to continuously emit characteristic rays, nuclear detectors can be used to track its position, quantity and transformation in vivo or in vitro at any time. Although stable isotopes do not emit rays, they can be used to correspond to ordinary The mass difference between isotopes is measured by mass spectrometers, gas chromatographs, nuclear magnetic resonance and other mass analysis instruments. If radioactive substances irradiate the human body or enter the human body, it will cause cell lesions, which will seriously endanger human life. The tungsten alloy shielded needle can protect the human body from harm when using radioactive substances.
Tungsten Alloy Shielding Can
Tungsten alloy shielding cans are also a type of tungsten alloy shielding products, which are used in medical containers for radiopharmaceuticals. Radiopharmaceuticals are a special class of drugs that contain radionuclides for medical diagnosis and treatment. A radionuclide-labeled compound or biological agent used for medical diagnosis or treatment in the body. Such as radiotherapy drugs 32P, 89Sr, 90Y, etc., which emit pure β-rays. Tungsten alloy shielding cans are mainly used to shield medical radioactive injections, medicines, and radioactive source materials such as X and gamma rays. Tungsten alloy shielding cans are also used for shielding of radioactive materials such as geological exploration.
Production Process
Sintering process is the main production process of tungsten alloy shielding parts. Sintering is a heat treatment process in which the strength and density of the compact or powder body are very low. In order to improve the strength of the compact or the powder body, it is necessary to perform heat treatment under appropriate conditions. This is to heat the compact or loose powder to a temperature below the melting point of its basic components (about 0.7~0.8T absolute melting point), and keep it warm at this temperature, so that the powder particles are combined to improve their properties.
Sintering has a decisive influence on the properties of tungsten alloy shields. As a result of sintering, bonding between powder particles occurs, the strength of the sintered body is increased and, in most cases, its density is also increased. During the sintering process, the compact undergoes a series of physical and chemical changes, starting with the evaporation or volatilization of moisture or organic matter, the removal of adsorbed gas, the elimination of stress, and the reduction of oxides on the surface of powder particles; followed by diffusion between atoms , paste flow and plastic flow, the contact surface between particles increases, recrystallization occurs, grain grows and so on.
