October 12, 2002 was a memorable day for all the scientific and technological personnel of the Baicheng Conventional Weapon Test Base. The most sophisticated industrial CT equipment in China was official used in an appraisal test of a new type of rocket on that day. The test indicates that a new non-fault testing technology has come into being at the firing range test.

　　CT technology was warmly received

　　CT technology was first used in medical field, which has been called medical CT technology. It is very important in medical field, that's why it is called a revolution in medical diagnosis. With close cooperation of the Chongqing University, the scientific research personnel of the base developed a horizontal industrial CT machine in 2001, which was the largest horizontal industrial CT equipment with best technical performance in China.

　　The said industrial CT machine consists of ray source system, detector system, data collection system, mechanical scanning system, control system, and computer system and image hard copy output equipment.

　　The machine can inspect a workpiece as long as 8 meters and the ceiling thickness of steel is 150mm, and even internal crack as small as 0.02mm cannot not escape its "penetrating sight".

　　After live ammunition firing test, the barrel of a new type of artillery was inspected by the said industrial CT machine, and a slight deformation was found in the bore, which could not be found by naked eye or other means. The inspection indicated that the strength of the steel used to make barrel of the artillery was not up to the standard. Through the test, the army was able to provide valuable proposals for manufacturers and the research units to make technical improvement.

　　Avoiding radiation pollution in design

　　Like medical CT machine, industrial CT machine also has internal radiation sources and the radiation is several dozen times stronger than those of medical CT, which seriously threatens the safety of operators.

　　In order to ensure safety operation, the radiation source Cobalt 60 in the said CT machine was shielded with tungsten alloy to insulate most of radiation diffusion. In order to prevent ray diffusion from the detector hole during the operation, the designers made painstaking efforts to build a "zigzag corridor" between the control room and the equipment room to insulate the operators from the CT machine, at the same time the walls of CT machine room is 1 meter in thickness.

　　Not like other rays, rays emitted by the said CT do not reflect, therefore it will not cause secondary pollution. However, rays emitted in the said CT can ionize oxygen to produce ozone, which is harmful to health. The equipment room is especially designed with ventilation device to avoid radiation pollution.

　　Bright prospect for military and civilian applications

　　CT technology has now been widely used in the world, including its medical application. According to the incomplete statistics, China has over 4,000 CT machines at the moment.

　　As industrial CT machines are to inspect industrial products of different shapes, sizes and weights, and are in great variety, it is impossible to produce them in batches. Although a series of industrial CT products have been developed in China, it still cannot meet ever-increasing demand.

　　According to the experts, the said industrial CT machines can not only be used to the non-fault testing of conventional weapon, but also the non-fault testing and appraisal in civilian industries, such as space flight, aviation, navigation, metallurgy, machinery and building material.

　　By Li Yongfu and Jia Kun

　　(December 24, PLA Daily)