The paper aims to research shielding properties of metal materials to the radionuclides so as to monitor and deal with interference of shield which impacts on monitoring and identification of radionuclides during the nuclear terrorism and nuclear emergency. Three types of metal with different thickness and materials were used as shield to detect the shielding effect of them on the same radioactive source. It was found that metallic materials had strong shielding effects on the gamma spectrum below 200 keV, especially for the low intensity ray which was almost impossible to be detected. The shielding performance of the same kind of metal was proportional to the thickness. But sometimes the shielding effect of 4 mm aluminum cylinder was inferior to that of 3 mm steel tube. Therefore, we should fully consider the effects of shield with different materials and different sizes on the absorption of radiation in the actual scene of the radioactive nuclear detection and identification, thus to detect and identify radionuclides rapidly. It is of special significance in monitoring nuclear terrorism and nuclear emergency.%目的 为应对在核反恐以及核应急中屏蔽体对放射性核素的监测和识别干扰,对金属材料屏蔽体的放射性核素屏蔽性能进行研究.方法 选用三种不同壁厚、材质的金属作为屏蔽体,探测它们对同一放射源的屏蔽作用.结果 发现研究中的几种金属材料屏蔽体对200 keV以下的gamma射线均具有较强的屏蔽作用,尤其对于低强度射线,经屏蔽体后几乎无法检测到.同一材质金属,其屏蔽性能与壁厚成正比,但是4 mm铝筒的屏蔽效果比3 mm钢筒的屏蔽效果有时候还差.结论 在实际场景放射性核素探测识别中,应充分考虑到不同材质和不同壁厚的屏蔽体对射线的吸收影响,从而快速检测和识别放射性核素.这对核反恐和核应急过程中的监测有特别的现实意义.
展开▼
