Optimizing Digital Radiography Parameters for the Detection of Argon Bubbles in Molten Salt

X-ray imaging is widely used to study the dynamics of bubbles in metal ducts. This study proposes an efficient model to determine the minimum exposure parameters for digital radiography of 0.5-mm argon bubbles in molten salt. First, Monte Carlo method was implemented to model a digital radiography imaging system comprising an X-ray generator and a flat-panel detector. Second, two test objects were selected to validate the model by comparing simulation results with experimental data. Finally, the contrast-to-noise ratio (CNR) of bubbles was assessed across multiple exposure conditions to determine the minimum parameters required for bubble observation. Subsequently, after system optimization and parameter updates using orthogonal experimentation, the influence of five parameters on CNR was evaluated. The results show that the highest CNR for bubble images is obtained with a duct of 33.8 mm external diameter and 0.9 mm wall thickness ( ), using exposure parameters of 150 kV and 20 mAs and a Gd 2 O 2 S flat panel detector with a 139 μm pixel size. Based on the calculated results and realistic constraints, the parameters of 150 kV and 10 mAs are considered to be adequate for detecting 0.5 mm bubbles in molten salt, while remaining achievable in practice.