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C. Michelle O'Brien

Being an expert in x-ray dose traceability, Mrs. O’Brien maintains the four primary x-ray standards at the NIST while conducting comparisons between other national measurement institutions and facilitating x-ray dose measurement quality standards domestically. Her work results in medical dose traceability for mammography and ct scans, radiation worker dose accountability and U.S. government energy laboratory and military x-ray dose traceability. Mrs. O’Brien conducts proficiency testing which provides traceability for multiple accrediting organizations resulting in an exceptional secondary calibration laboratory network in the U.S. She served as the lead coordinator of a recent international comparison and has participated in twelve international x-ray comparisons. Combining her expertise in radiation calibration laboratories management, data collection procedures, uncertainty analysis and 17025 ISO assessment training, Mrs. O’Brien has conducted multiple technical site assessments of active calibration laboratories. During her time at the NIST she has participated in the fabrication of four radiation calibration facilities and has modernized multiple features. She has researched, fabricated, compared and installed two primary x-ray standards for new applications. Two awards received during her time at the NIST (93-present) have been for her outstanding dedication to the radiation calibration services. She participates on the IEC SC 62C/Working Group 3. As the NIST is a leading measurement institute, Mrs. O’Brien has been contacted from multiple other radiation calibration metrology laboratories and has provided instruction for the development of other facilities.

Mrs. O’Brien’s contributions to the continued advancements and refined radiation dose traceability in the US are made possible by the supportive working environment at the NIST and her technically diverse educational experiences. While working towards a B.S. in Physics, with a minor in environmental sciences, she earned an A.S. degree from the Chattanooga State (88) which facilitated two summer internships as an health physicist technician at Brookhaven National Lab (88, 89). Upon completion of her B.S. at the University of Tennessee, Chattanooga, (90) degree, she supported volunteerism by joining the U.S. Peace Corps where she taught physics in Benin, West Africa (90). Her physics education was continued at the University of Tennessee, Knoxville where she earned a M.S. (93) in Health Physics while working as a research assistant preparing a radiation calibration laboratory for secondary calibration accreditation.



Radiation Physics Division
Dosimetry Group

Employment History:

NIST, 1993 - present


M.Sc, Physics, University of Tennessee, Knoxville, 1993


Phone: 301-975-2014
Email: michelle.obrien@nist.gov
Fax: 301-869-7682