Michigan Ion Beam Laboratory FOR SURFACE MODIFICATION AND ANALYSIS

This report summarizes the principal research activities in the Michigan Ion Beam Laboratory during the past calendar year. Fifty-six researchers conducted thirty-one projects at MIBL that accounted for over 3200 hours of equipment usage. The programs included participation from researchers at the University, corporate research laboratories, private companies, government laboratories, and other universities across the United States. The extent of participation of the laboratory in these programs ranged from routine surface analysis to ion assisted film formation. Experiments included Rutherford backscattering spectrometry, elastic recoil spectroscopy, nuclear reaction analysis, direct ion implantation, ion beam mixing, ion beam assisted deposition, and radiation damage by proton bombardment. The following pages contain a synopsis of the research conducted in the Michigan Ion Beam Laboratory during the 2008 calendar year. The Michigan Ion Beam Laboratory for Surface Modification and Analysis was completed in October of 1986. The laboratory was established for the purpose of advancing our understanding of ion-solid interactions by providing up-to-date equipment with unique and extensive facilities to support research at the cutting edge of science. Researchers from the University of Michigan as well as industry and other universities are encouraged to participate in this effort. The lab houses a 1.7 MV tandem ion accelerator, a 400 kV ion implanter, and an ion beam assisted deposition (IBAD) system. Additional facilities include a vacuum annealing furnace, a surface profilometry system, and a scanning laser surface curvature measurement system. The control of the parameters and the operation of these systems are mostly done by computers. They are interconnected through a local area network and the world wide web, allowing off-site monitoring and control. Spent AGR nuclear fuel bundles are stored in ponds prior to reprocessing. These may be susceptible to intergranular stress corrosion cracking (IGSCC). Mitigation is through the addition of sodium hydroxide as a corrosion inhibitor. IGSCC is attributed to chloride-induced corrosion at chromium depleted grain boundaries. Chromium depletion is a result of Radiation Induced Segregation (RIS). This project is aimed at simulating RIS levels in 20/25 Nb stabilized stainless steel cladding material by thermal sensitization and proton irradiation and exploring corrosion behavior in simulated pond water environments. Cladding material was proton irradiated using an irradiation energy of 2.2 MeV and a dose rate of 10-5 dpa/s to a penetration depth of 23m. Irradiations to 3 and 5 dpa at 400°C were performed. Analytical transmission electron microscopy has been used to examine grain boundary …