Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Ryan P. Fitzgerald (Fed)

Ryan Fitzgerald is a physicist in the NIST Radiation Physics division with a focus on development of primary standards for radionuclides for multiple applications (medical, energy, environmental, etc.). He is part of multiple collaborations exploring new and improved methods for measuring radiation and radioactive decay.

NRC Postdoc Opportunities

Projects & Collaborations

Publications

The Next Generation of Current Measurement for Ionization Chambers

Author(s)
Ryan P. Fitzgerald, Denis E. Bergeron, Dean G. Jarrett, Neil M. Zimmerman, Carine Michotte, Hansjoerg Scherer, Stephen Giblin, Steven Judge
Re-entrant ionization chambers (ICs) are essential to radionuclide metrology and nuclear medicine for maintaining standards and measuring half-lives. Metrology

Ohms Law Low-current Calibration System for Ionization Chambers

Author(s)
Dean G. Jarrett, Shamith U. Payagala, Ryan P. Fitzgerald, Denis E. Bergeron, Jeffrey T. Cessna, Charles J. Waduwarage Perera, Neil M. Zimmerman
A system for the calibration of electrometers that measure currents from ionization chambers is described. The calibration system uses a 1 GΩ standard resistor

Patents

Photonic Calorimeter and Process for Performing Calorimetry

NIST Inventors
Ronald Tosh, Zeeshan Ahmed, Ryan P. Fitzgerald and Nikolai Klimov
Patent Description The invention i s a photonic device whose resonance characteristics (such as, quality factor, peak position, and free spectral range) change in a predictable way in response to the interaction of radiation with the sensor and/or its surroundings. The invention can be used in an
A list of radiation-induced materials modifications that are NIST traceable

Photonic Dosimeter and Process for Performing Dosimetry

NIST Inventors
Ronald Tosh, Zeeshan Ahmed, Ryan P. Fitzgerald and Nikolai Klimov
Patent Description Radiation-induced materials modification is ubiquitous. These applications rely on dosimetry to reliably deliver the desired amount of radiation to the right place. Currently the dosimetry standard is based on calorimetry of a large water phantom irradiated exclusively by Co-60
Created May 21, 2019, Updated January 25, 2021