78
Diamond
Windows for High Power Microwave Transmission--Coating
Technology Solutions, Inc., 36 Munroe Street, #1, Somerville, MA
02143-2009; 617-625-2725
Dr.
Roy Gat, Principal Investigator,
Dr.
Roy Gat, Business Official,
DOE
Grant No. DE-FG02-02ER83387
Amount:
$746,298
High
power microwave gyrotrons, needed to initiate fusion reaction, require microwave
extraction windows with high thermal conductivity, low microwave absorption, and
low resistance to thermal cracking. Newly
developed, diamond windows fabricated with Chemical Vapor Deposition (CVD)
possess this combination of unique properties, but, thus far, CVD-diamond has
proven to be an expensive and unreliable solution.
This project will develop a new CVD deposition method that provides for
higher growth rates to lower the window costs. Also,
a non-destructive method will be developed for characterizing the diamond
components to ensure reliability, both prior to and during operation in
microwave-heated fusion and high power laser applications.
Phase I demonstrated feasibility by the successful deposition of a
two-inch-diameter diamond window, which met the specifications of the gyrotron
manufacturer. An approach for
developing a remote non-destructive technique to improve window reliability also
was identified. In Phase II, the
window deposition rate will be increased and the deposition area scaled up to
enable greater than the 1MW microwave transmission required for initiating
fusion. A non-destructive technique, based on the resonant ultrasound response
of the window to laser excitation, will be established for the remote detection
of the window’s mechanical state, in order to warn of impending window
failures.
Commercial Applications and Other Benefits as described by awardee: In addition to fusion research, the new diamond windows should benefit industries involved with large scale industrial microwave heating; CO2 laser metal cutting; and microwave sources such as gyrotrons and traveling wave tubes used by both the civilian and military sectors.