The Method of Differentiating Uranium Thin Layers from Agglomerates Based on Gamma Measurement

Based on the differences in the net count rate ratios of characteristic γ-rays (143, 163, 186 keV) of ²³⁵U between thin uranium layers and uranium agglomerate samples, a method for rapid discrimination of uranium agglomerates has been established.Monte Carlo simulations reveal that with increasing uranium metal thickness, both K_{143 keV/186 keV} and K_{163 keV/186 keV} net count rate ratios exhibit decreasing trends, with the K_{143 keV/186 keV} ratio demonstrating a significantly faster decline rate. When uranium thickness exceeds the saturation absorption thickness (2 mm) for 186 keV γ-rays, it is defined as uranium agglomeration, where the ratios stabilize (K_{143 keV/186 keV}=0.115, K_{163 keV/186 keV}=0.070). Below this threshold, it is classified as uranium foil. Experimental validation shows that measured ratios in uranium lump samples (0.113 and 0.067) deviate by less than 5% from simulated values (0.115 and 0.070). The study demonstrates that these ratio differences can enable rapid determination of uranium material distribution patterns: if K_{143 keV/186 keV} or K_{163 keV/186 KeV} ratios approach theoretical foil values (0.213/0.094), segmented gamma scanning (SGS) measurements remain reliable;If approaching agglomeration thresholds (0.115/0.070), self-absorption correction or measurement protocol optimization becomes necessary.