Physics O.M. Stewart Colloquium Series

Monday, October 1, 2018 4:00pm

Room 120 Physics Building


Hassina Bilheux

The MU Physics & Astronomy Department's O. M. Stewart Colloquium Series presents Dr. Hassina Bilheux, Oak Ridge National Laboratory, "Neutron Imaging Capabilities and Applications at the Oak Ridge National Laboratory’s Spallation Neutron Source and High Flux Isotope Reactor," on Monday, October 1, at 4:00 p.m.

Dr. Bilheux writes, "Historically, neutron imaging has been performed at reactor sources that offer a high flux of thermal and cold neutrons. At these facilities, attenuation-based neutron radiography and computed tomography have contributed to a broad range of scientific applications such as in energy storage, materials science and engineering, geosciences, plant physiology, geosciences, biology and archeology. We have installed a neutron imaging facility called CG-1D at the High Flux Isotope Reactor (HFIR) that is capable of measuring at spatial resolution ranging from 25 to 100 mm, and time resolution ranging from ms (for cyclic motions) to min. Three detectors are available at the CG-1D beamline: an ANDOR DW936 charge couple device (CCD), a ANDOR Zyla scientific complementary metal oxide semiconductor (sCMOS) detector, and a micro-channel plate (MCP) detector.  6LiF/ZnS scintillators of thickness varying from 50 to 200 mm are being used at this facility. ORNL is building a state-of-the-art neutron imaging facility named VENUS at the Spallation Neutron Source (SNS). A pulsed source enables the collection of wavelength-dependent radiographs. In crystalline structures, narrow dips or abrupt edges in the pixel intensity are measured at precise wavelengths specified by Bragg’s law; this technique is called Bragg-edge imaging. These variations in the transmission signal can be readily utilized to study the microstructure inside a crystalline structure.  Another technique, called resonance imaging, measures the isotopic-dependent absorption of neutrons at epithermal energies. These two techniques are currently being developed at the SNS in preparation of the VENUS beamline. This seminar will highlight some of the recent scientific research performed at both neutron sources."

A pre-talk reception will be held at 3:30 p.m. in Room 223A Physics Library. Refreshments will be served.