Accelerators in Industrial Applications

1) Irradiation processing

Radiation processing using electron beam or X-ray generated by an accelerator has become an important method and process for chemical, power, food, environmental protection and other industries. It is a new processing technology process. It is widely used in polymer crosslinking modification, coating curing, polyethylene foaming, heat shrinkable materials, semiconductor modification, wood-plastic composite material preparation, sterilization and preservation of food, smoke gas irradiation, desulfurization and denitrification, etc. .

The products produced by irradiation have many excellent characteristics. For example, the electrical performance and thermal performance of the polyethylene cable after irradiation with 105 Gy dose are greatly improved. The irradiation temperature is 60-70° C. before the irradiation, after irradiation. Long-term use temperature can reach above 120°C. At present, there are more than 40 production lines that have been irradiated with accelerators in China.

2) Non-destructive testing

Non-destructive testing is to detect their internal conditions without damaging or destroying materials, products or components. There are many modern methods for non-destructive testing, such as ultrasonic testing, eddy current testing, fluorescent detection, and ray detection. The ray inspection method can inspect the surface of the workpiece and can also inspect the defects inside the workpiece. The equipment can use gamma rays produced by a radioactive isotope Co60, low-energy X-rays generated by an X-ray machine, and high-energy X-rays generated by an electron accelerator. In particular, the flaw detection accelerator has high penetrability and high sensitivity. It is used as a verification method for final inspection or other inspection methods and in quality control, in large-scale cast-forged weldments, large-scale pressure vessels, reactor pressure shells, rocket solid fuels. The defect inspection of workpieces is widely used. This type of flaw detection accelerator uses an electron linear accelerator as the main model.

The method of ray detection can be divided into three types based on the different methods of ray acceptance and processing through the workpiece.

a. Radiography

This method is similar to our X-ray film on physical examination. The radiograph is an X-ray film. In the case of flaw detection, the film cassette with the X-ray film is placed behind the object to be inspected. After the workpiece is irradiated with X-rays, the film is exposed to the radiation through the workpiece, and the actual condition inside the workpiece is reflected on the film's latex. After the photosensitive film is processed, it is possible to clearly understand the presence or absence of a defect and the type, position, shape, and size of the defect.

b. Radiation imaging

The ray acceptor of this method is an array detector or a fluorescence sensitization screen. The former is a large container inspection product jointly developed and produced by Tsinghua University and Tsinghua Tongfang. The latter is an X-ray screening system for baggage and parcels used in airports and railways. It can also be used for industrial nondestructive testing. This method, together with an image processing system, can display real-world conditions in real-time online.

c. Industrial CT

Similar to the principle of medical CT, CT technology is computer-assisted tomography. The CT technology using an accelerator as an X-ray source is an advanced non-destructive testing method developed mainly for the detection of large solid rocket motors and precision workpieces. Its density resolution can reach 0.1%, an order of magnitude higher than conventional ray technology. In the aerospace, aviation, weapons, automotive manufacturing and other areas of precision parts defect detection, size measurement, assembly structure analysis, etc. have important application value.

3) Ion implantation

The use of an accelerator to inject ions of a certain energy into the surface of the solid material can obtain good physical, chemical and electrical properties. Ion implantation technology has been applied to semiconductor devices, metal material modification and large-scale integrated circuit production. China now has more than 100 various types of ion implanters. Among them, China has cumulatively produced more than 140 ion implanters with an energy of 150 KeV to 600 KeV (1 KeV=1×103 eV) and a current density of 0.5 mA to over a dozen mA.