Research Interests

• X-ray and synchrotron-based
characterization of
materials: Development and
application of advanced X-ray
scattering, imaging, and spectroscopy
techniques for probing microstructure,
electronic structure, and dynamic
processes in engineered and
nanostructured materials.
• High Explosives and Detonation
physics: Experimental investigations
into chemical, mesoscale, and
microscopic phenomena in high
explosives. Kinetics and mechanisms of
particulate, nanodiamond, and other
product formation and evolution during
detonation.
• Surface and interface science: X-ray
photoelectron and x-ray absorption
spectroscopies for electronic structure
of surfaces, molecular systems, and
nanomaterials

Graduate Certificate, National Security Affairs, Texas A&M University, 2014

Ph.D., Physics, University of California Davis, 2004

M.S., Physics, University of California Davis, 1999

B.S., Physics, Utah State University, 1997

Selected recent scientific publications:

O.A. Paredes Mellone, M.H. Nielsen, J.T. Babicz Jr, J. Vinson, T.M. Willey, D. Sokaras, “Deciphering decomposition pathways of high explosives with cryogenic X-ray Raman spectroscopy,” Proceedings of the National Academy of Sciences, 122 (23), e2426320122 (2025). https://doi.org/10.1073/pnas.2426320122

O.A. Paredes-Mellone, M.H. Nielsen, J. Vinson, K. Moua, K.D. Skoien, D. Sokaras, T.M. Willey, “Investigating the electronic structure of high explosives with X-ray Raman spectroscopy,” Scientific Reports, 12(1) 19460 (2022). https://doi.org/10.1038/s41598-022-24066-z

K. M. Champley, T. M. Willey, H. Kim, K. Bond, S.M. Glenn, J.A. Smith, J.S. Kallman, W.D. Brown, I.M. Seetho, L. Keene, S.G. Azevedo, L.D. McMichael, G. Overturf, H.E. Martz, “Livermore tomography tools: Accurate, fast, and flexible software for tomographic science,” NDT & E International, 126, 102595 (2022). https://doi.org/10.1016/j.ndteint.2021.102595.

T. M. Willey, J.R.I. Lee, D. Brehmer, O.A. Paredes Mellone, L. Landt, P.R. Schreiner, A.A. Fokin, B.A. Tkachenko, A. de Meijere, S. Kozhushkov, A.W. van Buuren, “X-ray spectroscopic identification of strain and structure-based resonances in a series of saturated carbon-cage molecules: Adamantane, twistane, octahedrane, and cubane,” Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 39(5) 053208 (2021). https://doi.org/10.1116/6.0001150

J.A. Hammons, M.H. Nielsen, M. Bagge-Hansen, S. Bastea, C. May, W.L. Shaw, A. Martin, Y. Li, N. Sinclair, L.M. Lauderbach, R.L. Hodgin, D.A. Orlikowski, L.E. Fried, and T.M. Willey, “Submicrosecond Aggregation during Detonation Synthesis of Nanodiamond,” The Journal of Physical Chemistry Letters, 12 (22), 5286-5293 (2021). https://doi.org/10.1021/acs.jpclett.1c01209

S.A. Khairallah, A.A. Martin, J.R.I. Lee, G. Guss, N.P. Calta, J.A. Hammons, M.H. Nielsen, K. Chaput, E. Schwalbach, M.N. Shah, M.G. Chapman, T.M. Willey, A.M. Rubenchik, A.T. Anderson, Y.M. Wang, M.J. Matthews, W.E. King, “Controlling interdependent meso-nanosecond dynamics and defect generation in metal 3D printing,” Science, 368(6491), 660-665, (2020).  https://doi.org/10.1126/science.aay7830

J.A. Hammons, M.H. Nielsen, M. Bagge‐Hansen, L.M. Lauderbach, R.L. Hodgin, S. Bastea, L.E. Fried, M.R. Cowan, D. A. Orlikowski, T.M. Willey, “Observation of variations in condensed carbon morphology dependent on composition B detonation conditions,” Propellants, Explosives, Pyrotechnics, 45(2), 347-355, (2020). https://doi.org/10.1002/prep.201900213

M. Bagge-Hansen, S. Bastea, J.A. Hammons, M.H. Nielsen, L.M. Lauderbach, R.L. Hodgin, P. Pagoria, C. May, S. Aloni, A. Jones, W.L. Shaw, E.V. Bukovsky, N. Sinclair, R.L. Gustavsen, E. B. Watkins, B.J. Jensen, D.M. Dattelbaum, M.A. Firestone, R.C. Huber, B.S. Ringstrand, J.R.I. Lee, T. van Buuren, L.E. Fried, T.M. Willey, “Detonation synthesis of carbon nano-onions via liquid carbon condensation,” Nature Communications, 10(1), 3819 (2019). https://doi.org/10.1038/s41467-019-11666-z

J. A Hammons, M. H. Nielsen, M. Bagge-Hansen, S. Bastea, W. L. Shaw, J.R. I. Lee, J. Ilavsky, N. Sinclair, K. Fezzaa, L. M. Lauderbach, R. L. Hodgin, D. A. Orlikowski, L. E. Fried, T. M. Willey, “Resolving detonation nanodiamond size evolution and morphology at sub-microsecond timescales during high-explosive detonations,” The Journal of Physical
Chemistry C, 123 (31) 19153-19164 (2019). https://doi.org/10.1021/acs.jpcc.9b02692

A. A. Martin, N. P. Calta, J. A. Hammons, S. A. Khairallah, M. H. Nielsen, R. M. Shuttlesworth, N. Sinclair, M. J. Matthews, J. R. Jeffries, T.M. Willey, J. R. I. Lee, “Ultrafast dynamics of laser-metal interactions in additive manufacturing alloys captured by in situ X-ray imaging,” Materials Today Advances, 1, 100002 (2019). https://doi.org/10.1016/j.mtadv.2019.01.001

For a full list, see:

Google Scholar
https://scholar.google.com/citations?user=SjkpNP0AAAAJ&hl=en&oi=ao
 

Scopus
https://www.scopus.com/authid/detail.uri?authorId=7004924935
 

ORCID
https://orcid.org/0000-0002-9667-8830

• Early- and Mid-Career Award, LLNL, 2019
• Director’s Science & Technology Awards, LLNL, 2017, 2016, 2013
• Department of Energy, Office of Science, Outstanding Mentor Award, 2010