Abstract:

Ion beam irradiation can produce diverse results, but most commonly, single crystals become disordered on specific lattice sites. New advanced techniques, particularly utilizing transmission electron microscopy (TEM), provide a unique tool not only to investigate the irradiation induced damage in materials and the damage recovery at a fundamental level, but also to process nanostructures of various types. The study of radiation effects has therefore found widespread applications in many different fields, e.g., radiation damage in nuclear fuels and waste forms, fabrication of nanomaterials, and fission track dating. This presentation will introduce some advances in these fields via a combination of ion irradiation techniques with the innovative methods newly-developed in this research. For example, tracks created by fission events in ceramics are randomly-oriented, linear radiation-damage regions about 10 to 25 μm in length but only several nm in diameter. In the absence of a method to observe the entire length of a latent, unetched fission track, the details of the structure and the process of the thermal-annealing of tracks have remained elusive. We have successfully imaged the entire length and in situ thermal annealing of latent tracks created by 80 MeV Xe ions implanted in apatite, through a novel TEM sample-preparation method by cutting the irradiated sample along the entire ion paths with a diamond knife.

Biography:

Dr. Weixing Li is currently a postdoctoral fellow working in the Department of Earth and Environmental Sciences at the University of Michigan, where he received his Ph.D. degree in Materials Science & Engineering and M.S.E. degree in Nuclear Engineering & Radiological Sciences in 2010. Dr. Li’s current research is focused on radiation effects in materials, ion beam modification of materials, and fission track dating by using transmission electron microscopy. Dr. Li also has a M.S. degree and a B.S. degree in Physics from University of Science and Technology Beijing (China) with experience in hard magnetic materials. He is the first author on seven journal papers and one patent.