Design of a High-Capacity Target Wheel for Automated PFAS Screening via PIGE*

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent chemicals linked to adverse health outcomes, including carcinogenicity, and are found in consumer products such as cosmetics and skincare items. We probe PFAS via fluorine quantification using particle-induced gamma-ray emission (PIGE) at UMass Lowell’s 5.5-MeV Van de Graaff accelerator with high-purity germanium (HPGe) detection. To enable high-throughput measurements, an effort to design and construct a high-capacity target wheel and a set of modular sample holders has begun. The holders are optimized to secure a piece of Whatman filter paper, onto which samples can be adhered or through which they can be filtered before drying, ensuring uniform geometry and reproducible positioning at the detector. The wheel accepts >70 samples and integrates fiducial alignment features for repeatable beam-spot placement. Initial commissioning runs demonstrate reliable motion and consistent count-rate stability across sequential positions. Although full integration with closed-loop beamline controls is ongoing, this inhouse hardware substantially reduces turnaround time and is expected to improve measurement, uniformity and throughput in upcoming PFAS screening campaigns. We will present the engineering design, fabrication choices, bench and beamline tests, and lessons learned for scaling to routine screening operations.