Research on radiation performance and safety performance of X-ray source for mine transmission detection

The X-ray source is the core component equipment of X-ray transmission detection. The stability and reliability of the X-ray source determine the performance of X-ray transmission detection. In order to meet the performance requirements of X-ray transmission detection, the tube voltage of X-ray source should be selected between 100-160 kV, and the tube current should be controlled between 0.1-4 mA. In view of the problem that the flameproof shell made of Q235 steel plate can greatly reduce the radiation output intensity of X-ray source, the X-ray transparent window made of tempered glass is installed on the flameproof shell of mine X-ray source to increase the transmission rate of X-ray. Taking the maximum tube voltage of 160 kV and the maximum tube current of 4 mA of X-ray source applied in the field of coal mine gangue selection identification transmission detection as an example, the maximum radiation output power of the mine X-ray source is calculated to be about 50 mW through actual measurement. The result meets the requirements of GB/T 3836.22-2017 Explosive Atmospheres-Part 22: Protection of Equipment and Transmission System Using Optical Radiation which stipulates that the radiation power shall not exceed 150 mW. In order to reduce the risk of the working temperature rise of the mine X-ray source, it is proposed that the X-ray tube should be made of the ceramic shell with good thermal conductivity. The anode of the X-ray tube should be directly fixed to the metal shell to increase the heat dissipation effect. The X-ray transparent window should be used to reduce the thermal power generated by the anode current of the X-ray tube. This will ensure that the surface temperature of the flameproof shell of the mine X-ray source is less than the 150 ℃ limit specified in GB/T 3836.1-2021 Explosive Atmospheres-Part 1: Equipment-General Requirements. In order to avoid the radiation impact of mine X-ray source on the surrounding environment, it is proposed to install the X-ray tube in a lead chamber made of 3 mm thick stainless steel and 5 mm thick metallic lead. This will shield the X-ray in non-working area, so as to ensure that the dose equivalent rate of X-ray leakage in the non-working area of the mine X-ray source is less than 2.5 µSv/h limit specified in GBZ 125-2009 Radiological Protection Requirements for Gauges Containing Sealed Radioactive Source.