John G. Barker

John Barker is a materials scientist at the NCNR at the National Institute for Standards and Technology in Gaithersburg, MD. He is responsible for a Bonse-Hart Perfect Crystal Diffractometer (USANS) on BT-5, and is also the center's safety representative.

Career History/Education:

• BS in Materials Science & Engineering, University of Minnesota (1984)
• PhD in Materials Science & Engineering, Northwestern University (1990)
• PhD thesis title: "Determination of Cavity Growth Rates During the High Temperature Fatigue of Copper."
• PhD thesis advisor: Julia R. Weertman.

Research Interests:

• Small Angle Neutron Scattering Research:
  Kinetics of precipitation and void formation in alloys and ceramics, scaling laws in polymer solutions.
• SANS Instrumentation:
  Parasitic background reduction, sample environment and holder design.
• SANS Data Reduction:
  Smearing and multiple scattering corrections to small angle scattering data.

Selected Publications:

• Barker, J. G.; Pedersen, J. S. Journal of Applied Crystallography1995, 28, 105-114 "Instrumental Smearing Effects in Radially Symmetrical Small- Angle Neutron-Scattering by Numerical and Analytical Methods"
• Drews, A. R.; Barker, J. G.; Glinka, C. J.; Agamalian, M. Physica B 1998, 241, 189-191 "Development of a thermal-neutron double-crystal diffractometer for USANS at NIST"
• Choi, S.-M.; Barker, J. G.; Glinka, C. J.; Cheng, Y. T.; Gamme, P. L. Journal of Applied Crystallography 2000 33, 793-796 "Focusing cold neutrons with multiple biconcave lenses for small-angle neutron scattering"

Other Interests:

• Soccer, Ultimate Frisbee, Hiking and Marathons

Contact Information:

• John G. Barker
  National Institute for Standards and Technology
  100 Bureau Drive, Bldg. 235, STOP 8562
  Gaithersburg MD 20899
• (301)975-6732 (office), (301)921-9847 (fax)
• john.barker@nist.gov

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Last modified 15-July-2005