Dependence of X‐Ray Fluorescence Intensity on Particle Size in Suspension‐Assisted TXRF Analysis of Mineral Samples

Particle size is a critical parameter in total‐reflection x‐ray fluorescence (TXRF) analysis of solid powders prepared as suspensions. In practice, for reliable quantitative analysis of powders via suspension, it is essential to minimize the particle size. In this paper, we propose a model for assessment of the dependence of x‐ray fluorescence (XRF) intensity on particle size for powders deposited on a reflective carrier. The model is based on the assumption that particles are uniformly distributed across the irradiated surface area on the carrier. To validate the model experimentally, minerals of varying hardness (fluorite, ilmenite, and copper sulfide) were used to compare theoretical and experimental intensity dependences for the SKα, KKα, CaKα, FeKα, and CuKα lines. The mineral samples were prepared with different particle size fractions: small (< 10 μm), intermediate (10–50 μm), and large (> 50 μm). The model was also applied to a multi‐component sample of Neolithic ceramics that was manually crushed for varying durations to produce different particle sizes. A comparison of the experimental data with the model's predictions demonstrates that the proposed approach is suitable for approximating the dependence of XRF intensity on powder particle size in TXRF analysis of suspension‐prepared samples.