矿用透射式检测用X射线源的辐射性能与安全性能研究

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

X射线源是X射线透射式检测的核心组成设备,其稳定性与可靠性决定了X射线透射式检测性能。为满足X射线透射式检测的性能要求,X射线源的管电压宜在100~160 kV之间选取、管电流控制在0.1~4 mA。针对由Q235钢板制造的隔爆外壳会大大降低X射线源辐射输出强度的问题,提出了在矿用X射线源的隔爆外壳上安装钢化玻璃制成的X射线透窗,增加X射线的透射率。以煤矿选矸识别透射式检测领域应用的X射线源最大管电压160 kV、最大管电流4 mA为例,通过实测计算出矿用X射线源的最大辐射输出功率约为50 mW,满足GB/T 3836.22−2017《爆炸性环境第22部分:光辐射设备和传输系统的保护措施》规定的辐射功率不超过150 mW的要求。为降低矿用X射线源工作温度升高的风险,提出了X射线管宜选用导热性能好的陶瓷壳体,X射线管阳极与金属外壳直接固定以增加散热效果,利用X射线透窗来减少X射线管阳极电流产生的热功率,从而保证矿用X射线源的隔爆外壳表面温度小于GB/T 3836.1−2021《爆炸性环境第1部分:设备通用要求》规定的150℃限值。为避免矿用X射线源对周围环境产生辐射影响,提出了将X射线管安装在用3 mm厚不锈钢+5 mm厚金属铅制成的铅室中,以屏蔽非工作区域的X射线,从而保证矿用X射线源的非工作区域X射线泄漏的剂量当量率小于GBZ 125−2009《含密封源仪表的放射卫生防护要求》规定的2.5μSv/h限值。

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 2.5μSv/h limit specified in GBZ 125-2009 Radiological Protection Requirements for Gauges Containing Sealed Radioactive Source.