基于能损计算的快速μ子吸收成像模拟研究

Fast Simulation Study of Muon Absorption Radiography Based on Energy Loss Calculation

μ子吸收成像技术使用天然存在的宇宙射线μ子作为辐射源,能够对大尺寸物体实现无损探测。在μ子吸收成像的应用研究中,进行成像的模拟分析是重要的一步。目前大部分的成像模拟通过蒙特卡罗方法模拟μ子在待测物体中的输运来实现,但使用蒙特卡罗方法进行模拟一般需要较长时间,不适用于一些需要快速得到模拟结果的场景。本文基于μ子在待测物体中的能损计算,实现了快速μ子吸收成像模拟,弥补了蒙特卡罗模拟用时过长的不足。具体地,本文根据待测物体的已知结构,通过能损与通量计算,获得μ子剩余通量的分布,进而实现成像。本文以胡夫金字塔为例,将构建的快速模拟过程与蒙特卡罗模拟进行比较,初步结果表明,使用本文的快速μ子吸收成像模拟获得的胡夫金字塔内部成像结果与蒙特卡罗模拟基本一致,快速模拟得到的通量值与蒙特卡罗模拟得到的通量值平均相差小于5%,快速模拟用时约为蒙特卡罗模拟的1/240。

Using natural cosmic ray muon as radiation source, muon absorption radiography can realize nondestructive detection of large-scale geological objects. Simulation analysis is an important step in the application of muon absorption radiography. Currently, most of the radiography simulations are carried out by simulating the muon transportation in the object to be measured using the Monte-Carlo method. However, using Monte-Carlo method usually takes a long time. It is not suitable for some scenes that need to get simulation results quickly. Based on the energy loss of muon in the object to be measured, the fast simulation of muon absorption radiography was realized, which makes up for the deficiency that Monte-Carlo simulation takes too much time. Specifically, according to the known structure of the object, the muon flux distribution was obtained through energy loss and flux calculation, and then the radiography results were obtained. Taking Khufu pyramid as an example, the results of fast simulation and Monte-Carlo simulation were compared in this paper. The preliminary results show that the imaging results of the internal structure of Khufu pyramid obtained by fast simulation are similar to the Monte-Carlo simulation, and the average relative difference between the flux obtained by fast simulation and Monte-Carlo simulation is less than 5%. It takes only about 1/240 of the time of Monte-Carlo simulation.