Caleigh Samuels
Radiation Dosimetry Lead
Caleigh Samuels is the Radiation Dosimetry Lead in the Center for Radiation Protection Knowledge at Oak Ridge National Laboratory. Her research in radiation dosimetry includes element-specific biokinetic model development, Monte Carlo applications in dosimetric and detector response modeling, development of radiological risk assessment tools, and dose reconstruction for internal emitters. Current focuses are on formulating models and methods to estimate organ doses from internal emitters for epidemiological studies of radiation workers, developing radiogenic cancer risk coefficients for public exposures, and simulating public and worker radiation doses associated with the detonation of nuclear explosive devices.
Samuels received her Ph.D in Nuclear Engineering and MS in Medical Physics from Georgia Institute of Technology, and her BS in Physics from Radford University. She is currently a member of ICRP Task Group 95 on Internal Dose Coefficients and of NCRP SC 6-13 on Methods and Models for Estimating Organ Doses from Intakes of Radium. She has been collaborating on the Million Person Study for over four years.
Richard Leggett
Distinguished Scientist
Richard Leggett is a research scientist in the Environmental Sciences Division at Oak Ridge National Laboratory. His main research interest is in physiological systems modeling, with primary applications to the biokinetics and dosimetry of radionuclides and radiation risk analysis.
He was a member of Committee 2 of the International Commission on Radiological Protection (ICRP) from 2009-2021 and is currently a member of the ICRP Task Group on Internal Dosimetry (INDOS). His physiological systems models of the human circulation, skeleton, and gastrointestinal transfer and his systemic biokinetic models for many elements are used by the ICRP as dosimetry and bioassay models. He is the author of ICRP Publication 70, Basic Anatomical and Physiological Data for Use in Radiological Protection: The Skeleton, and co-author of several other ICRP reports.
Scott O Schwahn
Senior Technical Program Associate
Scott O. Schwahn has served the scientific community as a health physicist (radiation safety professional) for over 30 years. He is the Senior Technical Program Associate in the Nuclear & Radiological Protection Division. Schwahn has worked largely for Department of Energy (DOE) prime contractors at high-energy accelerator facilities. For five years, he was a DOE employee, serving as the Performance Evaluation Program Administrator for the DOE Laboratory Accreditation Program for external dosimetry.
Having been a member of the Health Physics Society for 35 years, he has served in leadership roles continuously since 1997 including service as president of three chapters and one technical section, chair of several committees, task forces, and technical groups, and three years as a director. He was honored with the Society's Elda E. Anderson Award and was elected as a Fellow of the Society. He is an Associate Editor for the peer-reviewed journal Health Physics and has served as a United States delegate to the International Radiation Protection Association since 2012. He is a member of the Oak Ridge Institute for Science and Education Distinguished Scientists Advisory Board.
Schwahn has been Certified by the American Board of Health Physics since 1995 and has served on its Part II Panel of Examiners. He served as Treasurer for the American Academy of Health Physics and was the 2021 President for the Academy.
Amber Harshman
Environmental Dose Assessment Specialist
Amber Harshman is an Environmental Dose Assessment Specialist and senior technical staff member in the Environmental Protection Services Division at Oak Ridge National Laboratory. Her primary responsibilities include modeling and calculating radiation doses for the public and the environment from exposure to radiological discharges originating from operations and research activities conducted on the Oak Ridge Reservation for a variety of environmental pathways.
Prior to joining ORNL, she worked in nuclear power as a Health Physicist at Dresden Nuclear Power Plant, where she managed the internal and external dosimetry programs as well as the radiation protection instrumentation program for the site. She has a Ph.D. in Radiological Health Sciences from Colorado State University, and she is a Board-Certified Health Physicist and a Registered Radiation Protection Technologist.
Derek Jokisch
Director, Center for Radiation Protection Knowledge / Joint Faculty Appointee
Derek Jokisch is professor of Physics and Chair of the Department of Physics and Engineering at Francis Marion University in Florence, South Carolina where he has been on faculty since 1999. Since 2014 he has held a Joint Faculty Appointment with Center for Radiation Protection Knowledge (CRPK) at Oak Ridge National Laboratory and currently serves as its director.
Jokisch earned his bachelor’s degree in nuclear engineering from the University of Illinois and his master’s and doctoral degrees in nuclear engineering sciences from the University of Florida. He serves on dosimetry committees for both the International Commission on Radiological Protection and National Council on Radiation Protection and Measurements. From 2016 to 2024, he served on the US Scientific Review Group for the Department of Energy’s Russian Health Studies Program. Jokisch is a past recipient of the Elda Anderson Award from the Health Physics Society and the J. Lorin Mason Distinguished Professor Award at Francis Marion University.
Nicole Martinez
Joint Faculty Appointee
Nicole Martinez is a professor in the Department of Environmental Engineering and Earth Sciences at Clemson University and is a Joint Faculty Appointee within the Center for Radiation Protection Knowledge at Oak Ridge National Laboratory.
Her first professional position was as an officer in the U.S. Navy where she served just under four years, first as a nuclear power instructor and later a radiation health officer. She then worked for 2 years in industry before attending graduate school at Colorado State University where she specialized in health physics and radioecology.
Martinez’s current research focuses on dosimetric modeling and the behavior and effects of radiological contaminants in the environment for applications ranging from risk assessment to biosensing. In addition, she is interested in non-technical issues relevant to the field such as the roles of ethics, art, and culture in science and engineering. She is a Certified Health Physicist, on the Main Commission of the International Commission on Radiological Protection, and a member of the National Council on Radiation Protection and Measurements.
Ken Veinot
Y-12, Health Physicist
Ken Veinot is the senior Health Physicist at the Y-12 National Security Complex in Oak Ridge, TN where he has supported the internal and external dosimetry programs, instrumentation, and field operations organizations for more than 20 years.
His health physics interests include neutral and charged particle dosimetry and detection, computational dosimetry, radiation shielding, and operational radiation protection. He received his Masters of Science in Health Physics and Doctorate in Nuclear Engineering from the Georgia Institute of Technology and is certified by the American Board of Health Physics.
In addition to serving on numerous national and international scientific committees and standards working groups, he is the author or co-author of more than 30 papers in the peer reviewed scientific literature and multiple book chapters relating to health physics. He has been a lead assessor with the U.S. Department of Energy Laboratory Accreditation Program for over 20 years.