Mr. Shefsky is a Senior Research Scientist at Thermo Fisher Scientific Niton Analyzers. He contributed to the development of laboratory-based methods for measuring radon in air and water by liquid scintillation, to the design of portable electronic radon instrumentation, and to the design and operation of radon chambers and calibration systems. From 1990 to 2000 he was the director of quality assurance for Niton Corporation’s Radon Laboratory.