Events Calendar

Neutron Tomography For Material Characterization

Speaker: Dr. Dayakar Penumadu, red N. Peebles Professor and Head of Joint Institute for Advanced Materials and Chair of Excellence; Civil and Environmental Engineering, University of Tennessee, Knoxville, TN

Talk Title: - -

Abstract: Three dimensional neutron imaging is becoming an increasingly important research tool and a diagnostic technique, providing complementary information to X-ray imaging for a wide range of applications in science and engineering. Using a well collimated neutron beam and lens coupled neutron detector system comprising of a thin scintillator screen, low-noise CCD camera, suitable mirror coupled to a high quality lens system in a light-tight box, varying resolution neutron radiography and tomography images are obtained for target materials and working systems in a controlled sample environment. In this presentation, author will present example results from his research group associated with neutron tomography of metals (steel and aluminum alloys), polymeric composites and sandwich structures, and granular materials under partial saturation. Relevant recent advances associated with energy selective neutron imaging including Bragg-edge imaging and dark-field tomography will also be included. As an example of in-situ diagnostic ability, neutron imaging of a working PEM fuel cell for water management studies will be addressed. The unique ability of neutrons to penetrate high Z materials and have extraordinary contrast to light elements such as hydrogen offers potential for many new applications. To demonstrate the multi-modality of using combined information from X-ray and neutron attenuation through matter, author will use the example results on partially saturated compacted sand sample and polymeric composites subjected accelerated sea environmental degradation conditions. Theses sample were imaged using X-ray (13.2 µm voxel size) and cold neutron (29.8 µm voxel size) tomography using unique imaging facilities at the Helmholtz- Zentrum-Berlin (CONRAD) and thermal neutrons (10 µm voxel size) at National Institute of Standards and Testing (BT2), Gaithersberg. Both imaging modality systems provide relatively large field of view (FOV) and high spatial resolution for engineering applications. High resolution tomography offers unprecedented opportunity to study materials non-invasively for evaluating the microstructure and damage characterization quantitatively in three dimensions. Direct integration of reconstructed images into numerical methods for solving boundary value problems is a promising future direction.

Host: Veronica Eliasson

Location: Seaver Science Library (SSL) - 150

Audiences: Everyone Is Invited

Contact: April Mundy