Todd Williamson joined the Surface and Trace Chemical Analysis Group as a research chemist in 2020. Prior to joining NIST, Todd was a postdoctoral fellow and then staff scientist at Los Alamos National Laboratory (LANL) from 2005 - 2020. In his time at LANL, he was involved with applying isotopic measurements by secondary ion mass spectrometry (SIMS) to nuclear material related topics. This research primarily involved quantitative analysis of actinide containing particulate materials with a focus on improving the sensitivity of measurements to more adequately differentiate isotopic sub-populations within a sample. He also explored the measurement of material systems that are currently considered difficult to measure by SIMS, such as U/Pu measurements within the same material. Prior to that research, his work at LANL involved the MBE growth of nitride semiconductors and superconductors for photovoltaics, light emission, and sensor applications. His current research interests are applying SIMS analyses to nuclear materials metrology challenges.