Ionization chamber, also known as ion chamber, is the simplest of all gas-filled radiation detectors, and is widely used to detect and measure some kinds of ionizing radiation (including X-rays, gamma rays and beta particles). It consists of different electrodes which have different potential and the dielectric between them. When the ionization chamber is under the irradiation, the rays will interact with gas molecules, and produce ion pair in the dielectric. Then these ion pairs free spread to the surrounding area to form the ionization current under the action of electric field. Since the electric current is proportional to the intensity of ionizing radiation, the intensity of ionizing radiation can be obtained by measuring the electric current. The classification of ionization chamber is extremely complex, it can be divided into treatment α ionization chamber, β ionization chamber or α and β ionization chamber, γ ionization chamber, neutron ionization chamber, electron beam ionization chamber, Bragg peak ionization chamber according to the measuring object; and can be divided into shell ionization chamber, parallel-plate ionization chamber, ionization chamber ventilation according to the shape of the ionization chamber .

Radiation including α-rays, β-rays, neutrons, X-rays and γ-rays can cause the ionization of matter. α-ray, also known as " alpha ray ", refers to the α particle flow released from the radioactive material. Although its penetrate power is weaker than β-ray, its ionization effect is stronger that can greatly damage the human body tissues; the ionization effect of β ray is much weaker than the α-ray, but it can also damage human tissues due to its strong penetrate power; X-rays and γ-rays both have strong penetrate power and can cause harm to humans. When the body is irradiated with the radiation, radiation can restrain, damage or even kill human cells, different degrees of change in human physiology, pathology and biochemical aspects. Ionizing radiation can also cause skin damage, hematopoietic disorders, fertility damage, leukopenia, cancer, fetal death, fetal malformations and other diseases.

Tungsten alloy shielding can be used to shield radiation when using the ionization chamber to detect ionizing radiation. According to the research, the ray absorbing ability of shielding material is closely related to its density, the higher density means better shielding capability. Compared with other traditional materials (such as lead), tungsten alloy has higher density, therefore has better ray absorption capacity and shielding ability. And tungsten alloy shielding will not release toxic substances, will not endanger human health or pollute the environment.　

The main raw material of tungsten heater is tungsten filament. Due to its high melting point and strong corrosion resistance, it is widely used in vacuum gilding, aluminum and other decorative items. Vacuum coating is a kind of technology for making film by physical methods. The technology was developed in the 1930s, once it has been introduced, it enjoyed a great popular. This technology was first used in the production of optical lenses, such as telescope disk for sailing. Later it extended to other functional film, music aluminum, decorative coating and surface modification, such as machine tool coating, change processing hardness. Tungsten heater can be twisted into a single strand or multi-strand shape in according with different applications.

Firstly, before designing the appearance of tungsten heater, hank knotting and the heater surface should keep clean, bright without any cracks and visible contamination of impurities, such as oxides and filament drawing lubricants. If there exist impurities on its surface, it will affect the quality of vacuum and influence on the free evaporation rate of the metal, which will reduce the effect of vacuum coating. For the superficial area of tungsten, under the premise of constant power, it should be as large as possible. Size of superficial area is in direct proportion to rate of evaporation, the larger the area, the faster the evaporation. What’s more, it has a direct impact on the quality of vapor deposition and the infiltration flow performance of aluminum.

If it is a single strand tungsten filament, people should choose a relatively thin one whose appearance diameter should be between 0.5 ~ 0.8mm. In the design of the inner diameter of the spiral time, people need to consider whether aluminum can be put in it for many times. On the other hand, it should be ensure that the heat can be effectively concentrated. The pitch of screw thread should be designed for concentrating the heat and the appearance tension of molten aluminum in order to avoid droplet phenomenon.