放射性废物桶层析γ扫描动网格重建技术分析

提出一种应用于层析γ扫描技术（Tomographic Gamma Scanning, TGS）发射重建的自适应动网格加密算法.模拟了3种不同介质密度下不同位置单点源与多点源的TGS测量，对透射与发射重建结果进行了分析.结果表明，在多数情况下动网格的发射重建误差明显低于固定网格，网格数也少于固定网格；随着发射源半径增大或介质密度的增大，固定网格的发射重建误差也增大，但是动网格的发射重建误差相对较小，说明TGS在采用动网格进行发射重建后对整个废物桶截面以及对高密度介质均能取得较高的测量精度.

Analysis on Reconstruction Technique Using Dynamic Grids in Tomographic Gamma Scanning Method for Radioactive Waste Drum

A new image reconstruction algorithm employing dynamic grids technique was proposed for tomographic gamma scanning (TGS). The process of detection was simulated aiming at the single-point and multi-point sources in the matrix with three different densities. The results of the transmission reconstruction and emission reconstruction exhibit that the emission reconstruction error and grids number by using dynamic grids is less than that by using fixed grids in most cases respectively. Moreover, with the increase of the source position radius or the matrix density, the emission reconstruction error of fixed grids will increase, but the error still maintains the low level if dynamic grids are applied. It is indicated that the high detection accuracy is obtained for the full segment of radioactive waste drum filled with high density matrix if dynamic grids are used in TGS emission reconstruction.