Ward Johnson is a physicist with a background in innovative acoustic metrology and the effects of nanoscale dynamics and material structure on macroscopic vibration. He is a graduate of the Physics Department of the University of Illinois at Urbana-Champaign, with a PhD thesis focused on anelastic effects of radiation-induced point defects in semiconductors. In 1987, he joined the Metallurgy Division of NIST in Gaithersburg and, in 1994, transferred to the former Materials Reliability Division of NIST in Boulder, which is now part of the Applied Chemicals and Materials Division. His work at NIST has included the development and application of methods for characterizing mechanical properties of macroscopic, microscopic, and nanoscale materials using resonant acoustics, pulsed-laser ultrasonics, and Brillouin light scattering. It has also included the development of methods for characterizing mechanical fluctuations of bacteria and the effects of antibiotics on these fluctuations through measurements of phase noise of resonant crystals on which the bacteria are adhered.
Current research pursuits include the development of methods for sensing performance-degrading defects in additively manufactured alloys through measurements of resonant acoustic nonlinearity and loss. Other on-going work is focused on identifying defects and physical mechanisms that degrade the resolution of resonant piezoelectric sensors in high-temperature applications and developing analytical methods for enhancing the accuracy of torsional quartz-vibrator viscometers.
Additional information on current research:
NIST News articles:
New NIST Method May Find Elusive Flaws in Medical Implants and Spacecraft