少铅/无铅材料对X射线屏蔽性能的检测方法研究进展

Research progress of testing methods for X-ray shielding performance of low-lead/lead-free materials

为科学合理地评价少铅/无铅材料的防护效果,需要准确检测该类材料的屏蔽性能。通过文献调研,结合现行相关标准,从X射线辐射质、检测设备和检测方法3个方面对防护材料屏蔽性能检测进行介绍。根据检测布局的不同可分为以下5种检测方法:窄射束条件下探测器与被检材料距离较远,无法探测到被检材料产生的次级辐射,因而不适用于少铅/无铅材料检测;宽射束条件辐射束立体角增大且探测器与被检材料距离较近,利于少铅/无铅材料检测,但对被检材料面积以及探测器选取方面存在一定要求;逆宽射束条件通过窄束以及平板电离室实现检测,但存在小野问题;改进的逆宽射束条件利用IB-AT和IB-AP两种布局减少衰减前后能谱的差异,但实施较为繁琐;改进的宽射束可降低小野问题带来的影响,但仍存在衰减前后能谱差异对结果带来的影响。在实际操作中可根据其实验条件和具体防护需求选择相应的检测方法。

To scientifically and rationally evaluate the protective effect of low-lead/lead-free materials,the shielding performance of such materials needs to be accurately tested.Through literature research,combined with the current relevant standards,this paper introduces shielding performance testing of protective materials from three aspects of X-ray radiation quality,testing equipment and testing methods.According to the different test geometry,there are five detection methods as follows:under the condition of narrow beam,the detector is far away from the material to be tested,so it can not detect the secondary radiation generated by the material to be tested,so it is not suitable for the detection of low-lead/lead-free materials.Under the condition of broad beam,the solid angle of the radiation beam increases and the detector is close to the tested material,which is conducive to the detection of low-lead/lead-free materials,but there are certain requirements for the area of the tested material and the selection of the detector.The inverse broad beam condition is detected by narrow beam and flat ionization chamber,but there is a small field problem.The improved inverse broad beam condition uses IB-AT and IB-AP configurations to reduce the difference of energy spectrum,but the implementation is cumbersome.The improved broad beam can reduce the influence of the small field problem,but there is still the influence of the energy spectrum difference on the results.In practice,the appropriate test method can be selected according to conditions and specific protection needs.