金属材料对放射性核素的屏蔽性能研究

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 ke V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。

The Study on Shielding Properties of Metal Materials to the Radionuclides

Objective Nuclear and radiological terrorism has increasingly become a major means of terrorist attack because of its relatively low cost, easy to put on and so on, nuclear terrorism and nuclear emergency has become an important issue facing humanity. In order to deal with the interference of shield which impact on monitoring and identification of radionuclides during the nuclear terrorism and nuclear emergency, the shielding properties of the metal materials were studied. Methods Three different sizes and materials of metal are used as shield to detect the shielding effect of them on the same radioactive source. Results It is found that the shield body have strong shielding effects on the gamma spectrum below 200keV, especially for several tens of keV weak peaks and the shielding performance of the same kind of metal is proportional to the thickness. But sometimes the shielding effect of 4mm aluminum cylinder is worse than that of 3mm steel tube. Conclusion Therefore, we should fully consider the effects of different materials and different sizes of shield on the absorption of radiation in the actual scene of the radioactive nuclear detection and identification, thus detect and identify radionuclides rapidly. It is of special significance for the monitoring of nuclear terrorism and nuclear emergency.