Prediction of Liquid Density by Gamma-Ray Measurement for Materials with Low Atomic Number

A new method has been developed and evaluated for density measurement of liquid materials based on conventional gamma density meter, whether a low strength gamma radioactive source as the backscatter technique with collimated detector cannot be properly used for density measurement. In this comparative study, proposed method aimed to improve the linearity of the density measurement without using time consuming spectroscopy. Both transmission and backscatter methods for density measurement were used together in a combined model. The whole measurement system was designed, constructed and simulated for nuclear gamma–gamma density measurement. MCNP modeling results were benchmarked with experimental data, showing a good correlation between combined density measurement method and conventional transmission density measurement while values of MRE(%), RMSE and MAE(%) are lower in combined model. This study shows that, MRE(%) in combined model, and for both experimental and simulation results, is improved with the average of about 41% in comparison with the conventional density measurement. Also in this comparative study, RMSE decreased significantly about 56%. Additionally, average MAE (%) reduced about 36%. Furthermore, R-square values were also improved in both experimental and simulation results. Evaluating different methods of nuclear density measurements led us to propose an innovative formula, to investigate an accurate density measurement. This paper discusses advantages of proposed model in comparison with the conventional transmission method for gamma interaction with lower percentage errors and better calibration curve fitting.