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Patrick Egan (Fed)

Patrick began at NIST in 2006 as an NRC-NIST postdoc.  At the time, his focus was on the development of an optical frequency comb metrology system for the calibration of vacuum-wavelength.  In 2008 he began to investigate highly precise measurements of the refractive index of air using a Fabry-Perot cavity-based refractometer.  The work culminated in one of the most accurate measurements of the refractive index of nitrogen and argon at 633 nm, and laid the groundwork for what developed into the 2012 Innovation in Measurement Science (IMS) project entitled "Reinventing pressure, temperature, and length".  Since 2012 he has been part of the team attempting to use highly accurate measurements of gas refractivity to realize the pascal.  As of 2017 the project is ongoing.

Since 2015 Patrick has been a staff member of the Dimensional Metrology Group, and leader of the SI Length and Traceability project.


Shrinks When It's Colder

Patrick Egan
Thermal expansion can be a leading cause of uncertainty in length metrology. A cell-based refractometer has been designed at NIST which targets 10^-6} relative

D-to-A_eff converter

Patrick Egan, Eric S. Stanfield, John R. Stoup
Recent developments in diameter metrology at NIST have enabled the dimensional characterization of piston-cylinder assemblies (PCA) with unprecedented precision

Patents (2018-Present)

Image for 10,816,325

Deformometer for Determining Deformation of an Optical Cavity Optic

NIST Inventors
Zeeshan Ahmed , Kevin O Douglass , Stephen Eckel , Patrick Egan and Jay H. Hendricks
A superconducting waveform synthesizer produces an arbitrary waveform and includes an encoder that produces a bitstream; a pattern generator that produces a current bias pulse from the bitstream; a Josephson junction that produces a quantized output pulse from the current bias pulse; and a converter
Created October 23, 2018, Updated December 8, 2022