基于μ子动量谱的多群模型测量平板材料的厚度北大核心CSCD

在基于μ子多重库仑散射的断层成像技术中,天然宇宙射线中不同动量的μ子在同一目标对象中的散射特性存在明显的差异,这在一定程度上影响了成像分辨率。为了减少或消除这种不利影响,建立了一套基于天然宇宙射线μ子动量谱的多群模型,并检验其用于铅板厚度测量及平板材料识别中的性能和特征。结果表明,采用基于μ子动量谱的多群模型能够实现1~16cm范围内铅板厚度的准确测量,相对误差小于5%。此外,该多群模型还可以通过计算辐射长度来识别未知平板的材料组成,尤其是对于高原子序数材料组成的平板,其辐射长度相对误差小于4%。

Geant4Muon momentum spectra analysis by multi-group model for thickness measurement of slabs

In muon tomography based on multiple Coulomb scattering, the scattering properties of cosmic-ray muons are distinctive even for the same target due to their different momentum distribution, which, to some extent, cast down the imaging resolution. For the purpose of suppressing or eliminating this effect, a multi-group model (MGM) of the momentum spectra of cosmic-ray muons was set up and validated by measuring the thicknesses of Pb slabs and by identifying the materials of unknown slabs. The results show that MGM can give a precise calculation of Pb slab thickness in the range of 1-16 cm, within an error of 5%. Moreover, MGM can also identify the materials of slabs by calculating the corresponding radiation lengths, which is especially effective for high-Z materials with an calculation error below 4%.