MRI: Acquisition of a Positron Annihilation Lifetime Spectrometer for Enhanced Materials Characterization

Austin Peay State University, Clarksville TN

Investigators

Abstract

The instrument acquisition provides state-of-the-art capability of positron annihilation lifetime spectroscopy for advanced undergraduate research and characterization of the materials' void structure at (sub)nanoscale. The equipment will fill in a critical gap in the materials characterization infrastructure at Austin Peay State University, providing a vital information on the electron density-free sites (e.g. pores, voids, vacancies and other defects) in organic, inorganic, and biological substances. It will significantly boost interdisciplinary faculty activity in such emerging areas as materials for biomedical applications, telecommunication, energy storage and conversion, information processing and storage, sensors, photonics, and optoelectronics. The instrument will be designated as a shared facility, serving not only the internal research needs, but also the needs of other academic institutions and regional small businesses working in materials science disciplines. Being a rare facility in USA (compare to Europe, China or Japan, where it is used on a regular basis), it has a potential for international and domestic industry-university partnership to develop new advanced materials, promoting the progress of materials science in Tennessee and across the nation. Undergraduate students participating in the research projects will be exposed to cutting-edge knowledge in materials science and particle physics, which will increase their competitiveness on the labor market and future endeavors. They will also gain an experience of using the modern experimental techniques and worldwide approaches in radiation physics. This proposal requests funds to acquire a picosecond timing system for positron annihilation lifetime spectroscopy (PALS) with 200 ps (or better) time resolution, adjustable detectors assembly, and quick and convenient data acquisition system. PALS will be used for studying the spatial heterogeneities in crystals, glasses, liquids, polymers, and composites. It serves as a complementary technique to structural characterization methods, capable of probing both open and closed pores of sizes ranging from atomic scale to several tens of nanometers, as well as the electric charge distribution. Especially, this technique is valuable for the investigations of disordered materials (e.g. glasses, ceramics), which physical properties are known to be determined not only by their atomic sub-system, but also by voids which inevitably appear as a result of non-equilibrium conditions of their synthesis/preparation. PALS capability will significantly improve the ongoing research activity at Austin Peay State University (APSU), enhance the nature and quality, as well as enable new science and directions. As a cutting-edge instrument, it will be used to educate and train undergraduate students in physics, as well as chemistry and biology, which will increase the APSU ability to satisfy its educational mission. The researchers plan to incorporate scientific breakthroughs made possible by PALS into undergraduate curriculum, and will strengthen their outreach to K-12 students, industry, national labs and academia, in Tennessee and across the nation. Having this instrument will make APSU a more attractive institution for domestic and international collaboration, which will enable students exchange and REU programs, as well as joint research projects. The PALS instrument, as shared facility, will also enhance the capabilities of research in TN area towards void structure characterization.