X‐Ray Fluorescence Methods and Performance of the Tender‐Energy Spectroscopy Beamline at Shanghai Synchrotron Radiation Facility

ABSTRACT Synchrotron radiation X‐ray fluorescence spectroscopy (SR‐XRF) has revolutionized elemental analysis by achieving detection sensitivity enhancements of up to three orders of magnitude compared with conventional laboratory X‐ray tube‐based XRF systems. This enables trace element analysis from parts per million (ppm) to parts per billion (ppb) levels in environmental, materials and biomedical applications. The Tender‐Energy Spectroscopy Beamline (BL16U1 beamline) at the Shanghai Synchrotron Radiation Facility (SSRF), equipped with a high‐brightness undulator, operating within the 2.1–16 keV energy range. The beamline has been optimized in the tender‐energy range (2–5 keV), and supports high‐sensitivity analysis of medium‐Z elements (e.g., sulfur, phosphorus) at its experimental station. At the station an exceptional detection limit of 4.1 ppb for copper has been achieved, which supports highly sensitive fluorescence XANES/EXAFS detection, and there integrates multiple advanced features: Kirkpatrick‐Baez mirror system enabling micrometer/sub‐micrometer spatial resolution, and wavelength‐dispersive spectroscopy technology supporting simultaneous multi‐element detection. These capabilities support diverse cutting‐edge applications, ranging from energy and environmental analysis to cellular trace element imaging, cultural heritage examination, and battery materials research. BL16U1 beamline and experimental station represents a significant platform for advancing XRF methodologies, with ongoing developments expected to further expand its impact on trace element research across multiple scientific disciplines.