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Radiation Physics Division


The Radiation Physics Division is a division of the Physical Measurement Laboratory at NIST. We develop, maintain and disseminate the national standards for ionizing radiations and radioactivity, and research and develop the measurement methods and models to address problems in biophysics. The Division fulfills its mission to support the measurement and standards needs of the health care, biotechnology, security and defense, energy, and other industries through activities in four technical groups:

  • Biophysics,
  • Dosimetry,
  • Neutron Physics,
  • and Radioactivity.

The Division advances measurement tools, science and applications in ionizing and non-ionizing radiation to support U.S. security, industry, protection, and trade and develops, maintains, and disseminates national measurement standards for these physical quantities and assesses their comparability internationally. The Division also conducts theoretical and experimental research on the fundamental physical interactions of ionizing and non-ionizing radiation with matter, including the development and evaluation of the key physical measurements needed in the study of biological systems and their functions as well as research on the basic mechanisms involved in radiation-induced chemical transformations and the parameters that influence the yields of short-lived intermediates, final chemical products, and biological effects.  We develop and operate well-characterized sources and beams of electrons, photons, and neutrons for primary radiation standards, calibrations, research on radiation interactions, and measurement methods development.  In addition to publications in the scientific community, the Division’s products are disseminated through highly accurate standard reference data for ionizing radiation and radioactive materials, Standard Reference Materials (SRMs), calibrations, and measurement quality assurance providing measurement traceability to users such as hospitals, industry, states, and other Federal agencies.


Photovoltaic Carrier Dynamics Measured by Time-Resolved Terahertz Spectroscopy—Far-infrared (or THz, 25 to 300 micron wavelength) femtosecond laser methods are employed to measure photovoltaic (PV) materials spectra and photocarrier dynamics in candidate polymeric and …

Ultrafast Molecular Switch Dynamics Examined by Mid-Infrared Femtosecond Spectroscopy—Ultrashort mid-infrared laser pulses are used to observe fast molecular and photochemical reaction processes occurring in the condensed phase. We have developed unique femtosecond broadband …

Terahertz Bi-Directional Reflection Function Measurements and Imaging for Homeland Security—Far-infrared (or THz, 25 to 300 micron wavelength) femtosecond laser methods are employed to generate high power (ca. 1 µJ) broadband pulses for far-field imaging applications. We are developing …

Hydrogen Storage Optimization in Thin Film Combinatorial Alloys—Discovery of novel materials for hydrogen gas storage has prompted new avenues of research towards developing hydrogen as an alternative fuel. However, optimizing candidate materials’ properties …

Hydrogen Generation in Di-Iron Hydrogenase Mimics—Discovery of novel materials to facilitate hydrogen gas production has prompted new avenues of research towards developing hydrogen as an alternative to fossil fuel. Optimizing candidate material …

Far-infrared Spectroscopy of Biomolecules—Far-infrared (or terahertz/THz, ca. 25 to 300 micron wavelength) femtosecond pulsed laser and Fourier-transform infrared methods are employed to measure biomolecular spectra in the condensed phase. …


Karam 003

Lisa R. Karam, Division Chief
301-975-5561 Telephone
301-975-5524 Division Secretary
301-869-7682 Facsimile

100 Bureau Drive, M/S 8460
Gaithersburg, MD 20899-8460 

Division Staff