is Scientist Emeritus at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. He received a BA in physics and mathematics from Indiana Central College (now the University of Indianapolis) (1970) and a PhD in experimental nuclear physics from Indiana University Bloomington (1975). His career began with a postdoctoral appointment in nuclear physics research at the Texas A&M University Cyclotron Institute. He began his transition to health physics with his move to Fermilab in 1978 and led Fermilab’s radiation protection program from 1989 to 2020. He became certified by the American Board of Health Physics in 1982. He is a member of the American Physical Society, a Fellow Member of the Health Physics Society (HPS), and served as a Council Member of NCRP for 12 y before becoming a Distinguished Emeritus Member in 2007. His principal interests are in radiation physics and associated instrumentation at particle accelerators.

Along with Matthew Quinn, PhD, Dr. Cossairt in 2019 published a new textbook entitled Radiation Physics for Personnel and Environmental Protection. Dr. Cossairt has numerous publications in health physics, nuclear physics, and particle physics and has served on many review panels and has been a frequent lecturer at the academic sessions of the U.S. Particle Accelerator School. He was co-academic dean of the Professional Development School of the Health Physics Society in Oakland, California in 2008. He received a G. William Morgan Lectureship Award from HPS in 2011. He has contributed to several NCRP publications and commentaries, perhaps the most notable one being NCRP Report No. 144, Radiation Protection for Particle Accelerator Facilities (2003).