Day: April 22, 2013

MEEM Graduate Seminar: Seeing the World with Neutron Vision

Mechanical Engineering – Engineering Mechanics Graduate Seminar: Thurs., April 25 at 4:00 in 112 MEEM.

Dr. Daniel S. Hussey from the National Institute of Standards and Technology will be the ME-EM guest speaker for Thurs., April 25 at 4:00 in 112 MEEM. His presentation is entitled ‘Seeing the World with Neutron Vision’.

Dr. Daniel S. Hussey is a research scientist at the National Institute of Standards and Technology where his primary research is on neutron optics including neutron imaging of proton exchange membrane fuel cells. Dr. Hussey started at NIST as a National Research Council Postdoctoral Fellow in 2004. Dr. Hussey earned a PhD in physics from Indiana University in Bloomington, IN in 2003 where he used dense samples of polarized 3He in polarized neutron reflectometry studies of magnetic thin films. Dr. Hussey earned his bachelor of science in physics from the University of New Hampshire in 1999. Dr. Hussey has authored or coauthored over 50 peer-reviewed journal articles and book chapters and was awarded the Presidential Early Career Award for Scientist and Engineers in 2010.

Abstract: “Seeing the World with Neutron Vision”

Neutrons primarily interact with matter via the strong nuclear force (as opposed to the electron density) and so provide a complementary view of world to more conventional probes of matter.

In particular, neutrons have a very high sensitive to hydrogen while being very insensitive to common metals such as aluminum. This has enabled neutron imaging to play a key role in understanding the water transport in hydrogen fuel cells. Neutrons can also be treated as waves and it is possible to construct a neutron Talbot-Lau interferometer to obtain phase and darkfield images which can increase the contrast for small variations in material density or porosity. An ongoing challenge in any neutron scattering or imaging measurement is the inherently low neutron intensity as compared to what is possible at modern x-ray synchrotrons. This is partly due to the difficulty in focusing neutrons as the refractive index differs from one by only 1-10 ppm. A new reflection base lens technology shows great promise to create the world’s first practical neutron microscope. In this talk, I’ll discuss how neutron imaging has benefited fuel cells and how it might be useful for lithium batteries, give an overview of the Talbot-Lau interferometer, and introduce the idea of the neutron microscope.