宇宙射线缪子地质体密度成像技术及其工程应用研究

宇宙射线缪子密度成像在检测低密度的空洞和破碎带方面有不可替代的优势，因其不受振动和电磁噪声的干扰，且不需在崎岖的地形上进行数据采集，因此我们尝试将宇宙射线缪子成像技术用于工程地质体密度的勘查。然而传统的缪子探测器体积庞大，而且通常需要漫长的观测时间来积累足量的具有统计意义的缪子通量数据。本文提出了可变角分辨率观测模 式以期用更短的观测时间实现目标体的有效成像：缪子探测器通过两块平行正对的塑料闪烁体像素矩阵记录缪子的到达，可以通过改变像素矩阵间距，对仪器的角度分辨率进行调节，较小的间距具有更广的接收视角，对射线路径的分辨率降低，但可以更快速的积累足量的缪子事件。同时，我们选择了像素数量更少的像素矩阵，以提高仪器的便携性。联合多个探测器的缪子通量数据共同反演，可以实现地质体的三维密度成像，用于工程施工路段不良地质体的勘探与监测，进而确保生产建设的安全进行。

为了验证可变角分辨率观测模式的可行性，本文：（1）首先研究了宇宙射线缪子密度成像正演算法，明确了射线方向不透明度与观测通量的转化关系；（2）在此基础上，展开了可变角分辨率缪子密度成像算法的研究，将各接收单元剖分为多个接收微元，以解决低角度分辨率观测模式下，单一射线方向正演的不透明度数据与实测不透明度数据存在较大误差的问题；（3）最后，在空腔和山体破碎带这两种不同尺度、不同类型的地质模型中，设置了高、低两种角度分辨率观测模式，正演计算观测通量数据，将其转换为观测不透明度后，基于该数据反演，对比不同数据采集时间对密度成像清晰度的影响，分析判断是否能用低角度分辨率（如像素矩阵间距 40 cm 时）观测模式在更短的探测时间内对目标体密度进行有效探测。

结果表明对于射线穿透长度较长，缪子观测通量较低的情况（如山体破碎带模型），低角度分辨率观测模式可以显著减少数据稳定所需的时间，并在更短的时间内对目标地质体进行有效密度成像，证明了可变角分辨率观测模式的有效性和必要性。实际测量中可以依据目标体尺度与探测时间和成像精度要求，对仪器的角度分辨率进行选择，进而更经济快速的实现地质体三维缪子密度成像，为工程建设的施工规划与灾害监测提供依据。

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