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*STTR Project: Surface Films to Suppress Field Emission in
High-Power Microwave Components—Omega-P, Inc.,
Dr. Jay L. Hirshfield, Principal Investigator, jay@omega-p.com
Dr. George P. Trahan, Business Official, trahan@omega-p.com
DOE Grant No. DE-FG02-04ER86223
Amount: $650,000
Research Institution
The use of high microwave fields in next-generation high-energy room-temperature particle accelerators requires, among other things, that field emission and breakdown be held to within strict upper limits. One means to achieve this goal is to devise rugged thin-film coatings for vulnerable copper surfaces that have higher work function than copper alone. This project will evaluate a variety of candidate thin-film coating materials for inhibiting field emission in high-power microwave components and develop recipes for applying these coatings to copper test blanks. In Phase I, measurements of the work function for copper-platinum alloys were conducted. The results showed that, depending upon the percentage of each element, an increase in work function of up to 1.2 eV could be achieved, compared with pure copper. In addition, a coldtest version of a breakdown test cavity cell was built and successfully tested. Phase II will refine techniques for applying 50-100 micron thick coatings of graded platinum-cooper alloys to copper test samples, in order to achieve good adherence of the coatings to the substrate. Test samples will be subjected to repeated X-band RF pulses, with pulse widths up to one microsecond and surface field strengths up to 600MV/m, to measure the incidence rate of breakdown events. Comparisons to the case of pure copper will be made.
Commercial Applications and Other Benefits as described by the awardee: RF breakdown is a major factor that limits the high-field operation of accelerator structures and microwave components. A process that can increase the reliability of these structures and components and to allow operation at higher fields could have wide-ranging commercial applications, representing a business opportunity of millions of dollars in annual sales. Applications to high-power radar systems are also possible.