Cody Dennett

  • Program Year: 2
  • Academic Institution: Massachusetts Institute of Technology
  • Field of Study: Nuclear Materials Science
  • Academic Advisor: Michael Short
  • Practicum(s):
    Sandia National Laboratories, New Mexico (2017)
  • Degree(s):
    B.S. Engineering Physics, Cornell University, 2014

Summary of Research

My doctoral research is focused on the development of a non-destructive, non-contact technique to measure the effects of accumulated radiation damage in materials. Traditional testing of materials for use in nuclear systems relies on post-irradiation examination, which is most often destructive, to determine the effects of radiation damage on the thermal and mechanical properties of the material in question. However, the in-operando value of these material properties can be vastly different than the value measured post-irradiation.

To fill this gap in characterization ability, we are designing an experimental facility that will allow us to continuously monitor certain thermal and mechanical properties of materials in-situ, during ion irradiation. To do this we rely on a photoacoustic technique called transient grating (TG) spectroscopy. We begin by pulsing the surface of a material under investigation with a spatially periodic intensity pattern. Thermal expansion on the sample surface launches monochromatic surface acoustic waves, whose propagation is measured using an interrogation laser. The characteristics of these oscillations provide values for thermal and mechanical properties of interest.

A combined ion irradiation and TG monitoring experiment will allow for the characterization of radiation-induced microstrucutral evolution with time resolution on the order of seconds. Using in-situ property monitoring during irradiation, we are studying the effects of ion beam rastering on long-term radiation damage accumulation. Additionally, this type of resolution also allows us to investigate the kinetics of the commonly observed transition between transient and steady-state void swelling in materials under high-dose irradiation.

Publications

Papers:
C.A. Dennett, K.P. So, A. Kushima, D.L. Buller, K. Hattar, and M.P. Short. Detecting self-ion irradiation-induced void swelling in pure copper using transient grating spectroscopy. Acta Mater., 145 (2018) 496-503

C.A. Dennett and M.P. Short. Time-resolved, dual heterodyne phase collection transient grating spectroscopy. Appl. Phys. Lett., 110 (21) (2017) 211106

C.A. Dennett, P. Cao, S.E. Ferry, A. Vega-Flick, A.A. Maznev, K.A. Nelson, A.G. Every, M.P. Short. Bridging the gap to mesoscale radiation materials science with transient grating spectroscopy. Phys. Rev. B 94 (21) (2016) 214106

M.P. Short, C.A. Dennett, S.E. Ferry, Y. Yang, J.K. Eliason, A. Vega-Flick, A.A. Maznev and K.A. Nelson. Applications of transient grating spectroscopy to radiation materials science. JOM 67 (8) (2015) 1840-1848

C.A. Dennett, M.P. Short, S.E. Ferry, J.K. Eliason, A.A. Maznev and K.A. Nelson. Applications of transient grating spectroscopy to radiation materials science. In, Transactions of the American Nuclear Society 112 (2015) 300-303

Presentations/Posters:
Ions and lasers: exploring new diagnostics for nuclear materials. At, MIT Nuclear Science and Engineering Graduate Research Expo, March, 2017. Invited.

C.A. Dennett, S.E. Ferry, P. Cao, M.P. Short. Developing continuous thermo-mechanical property monitoring for ion irradiation using transient grating spectroscopy. Presentation. Materials Research Society Fall Meeting. 2017.

C.A. Dennett, S.E. Ferry, P. Cao, M.P. Short. Developing continuous non-contact thermo-mechanical property monitoring for ion irradiations using surface photoacoustics. Presentation. 20th International Conference on Ion Beam Modification of Materials, 2016.

C.A. Dennett, P. Cao, A. Vega-Flick, J.K. Eliason, A.A. Maznev, K.A. Nelson, M.P. Short. Determination of unknown single-crystal orientation using transient grating spectroscopy and molecular dynamics simulations. Poster. TMS annual conference 2016.

C.A. Dennett, S.E. Ferry, V.K. Mishra, J.K. Eliason, A.A. Maznev, K.A. Nelson, M.P. Short. Non-contact determination of ion irradiation effects in pure polycrystalline copper. Presentation. TMS annual conference 2016.

Awards

DOE Innovations in Nuclear Technology R&D Award (1st place, Materials Protection), 2017
DOE NNSA Stewardship Science Graduate Fellowship, 2016-Present
Member, Alpha Nu Sigma, Nuclear Engineering Honor Society, 2016
National Science Foundation Graduate Research Fellow, 2014-2016
Hartman Prize for Excellence in Experimental Physics, Cornell University, 2014
Member, Tau Beta Pi, National Engineering Honor Society, 2013
Dean's Honor List, College of Engineering, Cornell University, 2010-2014