Design and Application of a Hemispherical XRF Secondary Target

ABSTRACT In x‐ray fluorescence analysis (XRFA), the use of secondary targets to suppress measurement background is a common practice aimed at reducing detection limits. However, conventional polarized secondary targets often exhibit low conversion efficiency of primary x‐rays. In this paper, we propose a novel hemispherical secondary target designed to exploit a focusing‐like phenomenon for primary x‐rays, thereby enhancing the conversion efficiency and achieving improved background suppression. The optimal dimensions of the hemispherical secondary target are determined through theoretical calculations, and further validated through Monte Carlo simulations and experimental analysis. Our findings reveal a substantial enhancement in the peak‐to‐background ratio when compared to traditional polarized secondary targets. Specifically, for a 1000‐ppm Ce sample, the peak‐to‐background ratio increased from 8.45 to 9.78 with the implementation of the hemispherical secondary target. Similar improvements were observed when measuring a 1000‐ppm Ce sample, relative to direct excitation. Furthermore, the relative error between the system and the ICP‐MS measurement results of the rare earth sample remains within 5%, underscoring the effectiveness of the hemispherical secondary target in XRFA applications.