Study on detection simplification of tomographic gamma scanning using dynamic grids applied in the emission reconstruction

• A new emission reconstruction algorithm employing dynamic grids is established in TGS technique.
• Grids are refined around emission sources which improves the detection efficiency accuracy in emission reconstruction.
• The new algorithm keeps the lower error of emission reconstruction than that of fixed grids in most detection schemes.
• The TGS detection time is reduced to half without losing detection accuracy if the dynamic grids are applied.

This paper presents a new emission reconstruction algorithm employing dynamic grids for tomographic gamma scanning in order to simplify the scanning process during the detection. Five types of scanning schemes to the single-point source and multi-point sources are studied aiming at both the uniform and heterogeneous matrixes in the radioactive waste drum. Comparing with the fixed grids, the error of emission reconstruction is obviously reduced if dynamic grids are applied. This reduction occurs because the grids are refined automatically around the emission source and consequently the precise positioning of the emission source leads to the low error of detection efficiency and emission reconstruction. Moreover, the simplification of the scanning process to half has less influence on the detection precision if dynamic grids are used, which will shorten the period of TGS detection.