Santa Barbara Research Center

Robert E Zahuta

Leonard E Peck

Timothy S Romano

Karl H Neumann

A dewar assembly is cleaned, baked out, assembled, and joined in a single vacuum system without exposing the components to ambient atmosphere. The vacuum system preferably has a first chamber with multiple subchambers that can be isolated from each other, and a second chamber that can be isolated from the first chamber. The multiple chambers and subchambers prevent cross contamination during the various process steps, and also permit multiple dewar assemblies to be batch processed at different stages simultaneously. The components of the dewar assembly are loaded into one subchamber and cleaned, and thereafter moved to another subchamber for bakeout. The dewar getter is heated in the second chamber and moved to one of the subchambers for assembly. The components of the dewar assembly are assembled and joined.

Processing of vacuum-sealed dewar assembly

A vacuum package assembly (20) is prepared by self-welding the flanges (32 and 43) of two housings (28 and 36) together under an applied pressure, while the housings (28 and 36) and any enclosed structure or device are contained within an evacuated enclosure. The flanges (32 and 43) are preferably made of copper, with their respective self-welding members (34 and 46) specially prepared to enhance self-welding performance. The preferred treatment for the self-welding members (34 and 46) is to deposit a thin layer of nickel onto the self-welding members (34 and 46 ), deposit a thin layer of gold over the nickel, and heat the bonding member to elevated temperature to interdiffuse the gold into the self-welding member (34 and 46 ).

Vacuum package tubeless enclosure with self-welded flanges

An infrared detector assembly (10) of the type used in munition and night vision systems having an RF activated getter (50). Such detector assemblies (10) include a tubular coldfinger (22) surrounded by a vacuum and which supports infrared detector array (26) and related components. In accordance with this invention, RF getter (50) is located remote from detector array (26) and engages an inner wall surface (56) of a metallic dewar housing (14). The RF getter (50) is activated via RF inductive heating directly through the metal dewar housing (14) such that sensitive IR detector components and hermetic braze joints are kept below their critical temperature. As a result, the present invention provides longer vacuum life and greater operational reliability of infrared detector assembly (10).

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Lompoc, CA, United States of America

Robert E Zahuta