High-Precision and High-Resolution X-ray Fluorescence Analysis System for Chlorine Elements Based on Double-Curved Crystal Technology

In X-ray fluorescence spectroscopy, specific elements, particularly neighboring elements, interfere with each other. A wavelength-dispersive optical system based on double-curved crystal (DCC) with multiple faces was designed. A Johann-type graphite curved crystal was used to focus the monochromatic excitation light, and a logarithmic spiral graphite curved crystal was used to collect the target fluorescence (Cl, 2.62 keV). The experimental results show that the wavelength dispersion device based on the DCC technology has a Cl detection limit of 0.18 part per million (ppm) when used for oil products. In the detection of a 1 ppm standard sample, the detection range of the device was 0.38 ppm, demonstrating good stability. Based on the fluorescence spectroscopy and detection results, the DCC technology could completely eliminate the influence of a high S concentration on Cl detection.