Dr. Essex has been a physical scientist in the Radioactivity Group at the National Institute of Standards and Technology since 2015. His primary responsibility at NIST are developing environmental level measurements of radioactive nuclides by mass spectrometry. Dr. Essex has degrees in Geological Science from the University of Rhode Island, Virginia Tech, and Brown University. He held several positions as an environmental regulator prior to becoming a staff member at the DOE’s New Brunswick Laboratory (NBL). Dr. Essex was at NBL for 14 years where his work included production and characterization of reference materials for analysis of nuclear materials, developing test materials for nuclear forensics analysis, and coordination of a DHS-sponsored program for production of reference materials. As part of his ongoing activities at NIST, Dr. Essex is working to enhance measurement of radioactive nuclides by developing isotope ratio mass spectrometry capabilities for radioactive material and contributing to an ongoing True Bq IMS prjoect.