Solid-State Nuclear Magnetic Resonance Investigations of Microwave Tube Cathode Structure
Abstract
The objective of this work was to determine if Solid-State Nuclear Magnetic Resonance (NMR) would be able to determine what chemical or structural changes occur during treatment of carbon fibers by CsI, and during operation of treated cathodes. It was known that CsI treated carbon fibers are superior to either solid CsI or untreated fibers when used as cathodes for high power microwave production. For C-13 NMR, probe background was a major problem. Even after efforts to remove it, the signals were very broad. There was useful difference between samples. I-127 spectra were obtained from standards and treated cathodes. The iodine that is seen appears to be CsI. However, it is possible that not all the iodine is being observed. Cs-133 is less sensitive than either carbon-13 or iodine-127, and no signals were seen from samples. Electron spin resonance (ESR) was also run, and there is some indication of radical formation during cathode use. Based on these results, it does not appear that Solid-State NMR is a useful tool in investigating these systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 2007
- Accession Number
- ADA475445
Entities
People
- Kevin A. Smith
Organizations
- University of New Mexico