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Dr. Andrew Allen

Research Interest

  • X-ray and neutron scattering-based microstructure characterization to address technological barriers in advanced materials development, for example
  • Nanoparticle formation, assembly and interaction, for industrial, biomedical and environmental health applications (including RM development in collaboration with National Cancer Institute).
  • Structure-property relationships in films, coatings and energy materials, including high-k dielectric films, thermal barrier coatings and solid oxide fuel cell materials.
  • Fundamentals of cement hydration, including the effects of additives and environmental conditions on concrete used in the nation’s infrastructure (with Federal Highway Administration).


Figure 1. Quantitative characterization of ceria nanoparticle formation reaction: (a) Fitted principal particle growth rates for different temperatures; (b) Arrhenius plot derived from (a); (c) Ratio of the fine feature/principal particle volume fractions versus reaction time; (d) Median principal particle diameter growth laws showing
universal behavior.

  Allen_Fig2a      Allen_Fig3b

Figure 2(left): 2D scattering patterns for near-surface small-angle neutron scattering (NS-SANS) data from various advanced thermal barrier coatings measured in situ on the substrate.; Figure 3(right): Ultrasmall-angle X-ray scattering (USAXS) instrument at the Advanced Photon Source set up for combined USAXS and X-ray photon correlation spectroscopy (XPCS) measurements on dental composites, automotive alloys, and infrastructural concretes.

Postdoctoral Research Opportunities

Microstructural Measurements for Fuel Cell and Hydrogen Storage Technologies:
Control of microstructure and chemistry is of primary importance in determining the performance and viability of solid oxide and polyelectrolyte membrane fuel cells, and other systems that advance the hydrogen economy. We seek to facilitate such control by utilizing unique instrumentation at the Advanced Photon Source, the National Synchrotron Light Source, and the NIST Center for Neutron Research, to elucidate the complex microstructure and chemistry of the advanced energy materials involved. For more information...

Microstructural measurements using X-ray and neutron scattering:
The NIST Ceramics Division has developed unique measurement capabilities in X-ray scattering and supports an active program at the NIST Center for Neutron Research. We seek to develop and utilize these measurement methods to overcome technology barriers in ceramic, metallic, biological, and polymeric materials. Experimental capabilities include high-resolution ultra-small-angle x-ray scattering, a high-temperature furnace for small-angle neutron scattering, and flow-cell instrumentation for both neutron and X-ray in situ studies of solution-mediated nanoparticle assembly and processing under controlled conditions. For more information...

Quantitative Measurement of Local and Nanoscale Structure in Nanomaterials:
Accurate knowledge of atomic arrangements and internal substructure in nanomaterials is a key to understanding their properties. Finding a comprehensive structural solution for nanostructured materials remains a formidable challenge. We seek to address this measurement problem by integrating theoretical analyses with critical experimental techniques such as total X-ray and neutron scattering for extracting atomic pair distribution functions, small-angle scattering, and extended absorption fine structure measurements. For more information...

Synchrotron Radiation Imaging:
The properties of high brilliance synchrotron radiation sources provide many unique opportunities to image the microstructure of a wide range of materials. MML utilizes beamlines at the Advanced Photon Source that provide opportunities in X-ray imaging including X-ray microbeam diffraction imaging (strain), phase contrast imaging, and ultrasmall angle X-ray scattering imaging. For more information...

Awards and Honors

  • Department of Commerce Bronze Medal Award, 2009
  • Department of Commerce Silver Medal, Group Award, 2008
  • Best Paper Award, Journal of Thermal Spray Technology, Volume 14, 2005
  • Co-Editor, Journal of Applied Crystallography, 2002-present
  • NIST Bronze Medal, Group Award, 1998
  • Best Paper Award, International Thermal Spray Conference, France, 1998
  • Advisory Editor, Journal of Physics: Condensed Matter, 1991-96
  • Open Exhibition Scholarship, Oxford University, 1974-1977


Physical Scientist (Physicist)
Ceramics Division
Structure Determination Methods Group

Employment History:

1995-present: Physical Scientist, Ceramics Division, NIST
1991-1995: Research Associate, NIST / University of Maryland, College Park, MD
1989-1991: Principal Scientific Officer, Harwell Laboratory, UK
1988-1989: Research Fellow, Northwestern University, Evanston, IL
1984-1989: Senior Scientific Officer, Harwell Laboratory, UK
1980-1984: Higher Scientific Officer, Harwell Laboratory, UK


Ph.D, Physics, University of Birmingham, UK, 1981
M.Sc. Physics, University of Birmingham, UK, 1978
B.Sc. Physics, University of Oxford, UK, 1977


Phone: 301-975-5982
Fax: 301-975-5334