Research on accurate virtual trajectory length model for TGS transmission measurement  

作　　者：Rong-Rong Su San-Gang Li Chu-Xiang Zhao Li Yang Ming-Zhe Liu Shan Liao Zhi Zhou Qing-Shan Tan Zhi-Xing Gu Xian-Guo Tuo Yi Cheng 

机构地区：[1]College of Nuclear Technology and Automation Engineering,Chengdu University of Technology,1#,Dongsanlu,Erxianqiao,Chengdu 610059,China [2]Applied Nuclear Technology in Geosciences Key Laboratory of Sichuan Province,(Chengdu University of Technology),1#,Dongsanlu,Erxianqiao,Chengdu 610059,China [3]University of Science and Technology of China,Hefei 230026,China [4]School of Physics and Electronic Engineering,Sichuan University of Science and Engineering,Zigong 643000,China

出　　处：《Nuclear Science and Techniques》2025年第3期178-188,共11页核技术(英文)

基　　金：supported by The Youth Science Foundation of Sichuan Province(Nos.2022NSFSC1230,2022NSFSC1231,and 23NSFSC5321);the Science and Technology Innovation Seedling Project of Sichuan Province(No.MZGC20230080);the General project of national Natural Science Foundation of China(No.12075039);the Youth Science Foundation of China(No.12105030);the Key project of the National Natural Science Foundation of China(No.U19A2086)。

摘　　要：To accurately reconstruct the tomographic gamma scanning(TGS)transmission measurement image,this study optimized the transmission reconstruction equation based on the actual situation of TGS transmission measurement.Using the transmission reconstruction equation and the Monte Carlo program Geant4,an innovative virtual trajectory length model was constructed.This model integrated the solving process for the trajectory length and detection efficiency within the same model.To mitigate the influence of the angular distribution ofγ-rays emitted by the transmitted source at the detector,the transport processes of numerous particles traversing a virtual nuclear waste barrel with a density of zero were simulated.Consequently,a certain amount of information was captured at each step of particle transport.Simultaneously,the model addressed the nonuniform detection efficiency of the detector end face by considering whether the energy deposition of particles in the detector equaled their initial energy.Two models were established to validate the accuracy and reliability of the virtual trajectory length model.Model 1 was a simplified nuclear waste barrel,whereas Model 2 closely resembled the actual structure of a nuclear waste barrel.The results indicated that the proposed virtual trajectory length model significantly enhanced the precision of the trajectory length determination,substantially increasing the quality of the reconstructed images.For example,the reconstructed images of Model 2 using the“point-to-point”and average trajectory models revealed a signalto-noise ratio increase of 375.0%and 112.7%,respectively.Thus,the virtual trajectory length model proposed in this study holds paramount significance for the precise reconstruction of transmission images.Moreover,it can provide support for the accurate detection of radioactive activity in nuclear waste barrels.

关 键 词：Tomographic gamma scanning Transmission measurement reconstruction Geant4 Trajectory length model Nonuniform detection efficiency 

分 类 号：O57[理学—粒子物理与原子核物理]