Development and characterization of a high-sensitivity and high-throughput in-house multimodal TXRF/GIXRF mobile spectrometer

Total-reflection X-ray Fluorescence (TXRF) and Grazing Incidence X-ray Fluorescence (GIXRF) techniques are non-destructive methods widely applied across diverse research domains. These methodologies capitalize on constructive and destructive interferences between grazing incident and reflected X-rays to generate an X-ray standing wave (XSW) field, optimizing excitation conditions at interfaces and reflective surfaces and minimizing background noise thus enabling highly sensitive depth-resolved specific analysis at the nanometer regime. High precision tuning of the angle of incidence allows detection of thin layers down to the nanometer scale. While TXRF is established in global laboratories, advanced methods like GIXRF have predominantly remained confined to synchrotron radiation facilities due to the need of high flux monochromatic X-ray sources as well as high level of control in the beam direction and its divergence. Successful implementation of lab-based GIXRF instruments is furthermore constrained by data evaluation capabilities, critical for accurately modelling experimental datasets and determining the effective solid angles of detection, that vary in a not trivial fashion with the incident angles. This article showcases the development of a fully functional high sensitivity and high through-put mobile TXRF/GIXRF system assembled in-house, utilizing high-efficiency new-generation sources, high-efficiency silicon detectors and a high-precision motorized rotational stage. The system's capabilities have been tested on a range of well-characterized samples in both total reflection and grazing incidence geometries. This approach allows for the detection of contaminants in the parts per billion range and the extraction of the depth profile of a layered sample in the nanometer range. Future improvements could focus on adapting the developed system for application on imperfect samples surfaces in cultural heritage studies.