Study of image reconstruction method for 2D gamma scan technique by anti-aliasing line "Xiaolin Wu" algorithm combined with simultaneous algebraic reconstruction algorithms and testing on MCNP simulation data

Abstract

The traditional 1D gamma scanning technique is known as an effective and popular method for surveying the condition of distillation towers in oil refineries. The technique involves measuring the intensity of a gamma beam transmitted through the tower from a radioactive source arranged opposite the detector to obtain a density profile inside the tower along its height. From the obtained density profile, the internal condition of the tower can be determined, such as the physical condition of trays, the liquid level on trays, and abnormal phenomena of fluid above and below the trays, such as flooding, foam on the liquid, and rain under the trays, etc. This technique has many advantages in terms of fast, simplicity and accuracy regarding the physical condition of trays. However, interpreting fluid-related issues is quite complicated and requires experience, but the interpretation results are still qualitative. The 2D gamma scanning technique proposed in recent years worldwide is an improved solution that provides visual cross-sectional images, showing hardware details as well as the internal density distribution of the tower. The 2D gamma scanning technique can be seen as a supplementary solution to the 1D technique to enhance the effectiveness of tower surveys, meeting the increasingly diverse needs of oil refineries. Studies on the approach of 2D gamma scanning technique have been conducted at Centre for Applications of Nuclear Technique in Industry. This report presents the research results on the method of reconstructing 2D gamma scanning images using the Xiaolin Wu anti-aliasing algorithm combined with simultaneous algebraic reconstruction algorithms (SART) and validates the method using MCNP simulation data.