Santa Barbara Research Center

Kenneth L Gustafson

Timothy S Romano

Nevil Q Maassen

Donald E Salzer

An infrared detector assembly (10) of the type used in munitions and night vision systems having an improved coldfinger assembly (42). Such detector assemblies (10) include a tubular coldfinger (22) which is surrounded by a vacuum and an end-cap (28) mounted to the coldfinger tube (22) to define a cold end (24) which supports the infrared detector array (30) and related components. In accordance with this invention, the coldfinger tube (22) is a thin-walled titanium cylinder and the end-cap (28) is made of tungsten. The components are metallurgically bonded at the cold end (24) by an active brazing alloy deposited during vacuum furnace brazing. The titanium coldfinger (22) provides the necessary bending stiffness to support cold end components. The tungsten end-cap (28) provides a low distortion, thermally stable focal-plane. The metallurgical bond (46) provides for a hermetic seal which inhibits structural distortion during brazing, and during cyclical cooling of the detector assembly (10).

Distortion free dewar/coldfinger assembly

A hollow, elongated tip-off tube 12 is comprised of a copper substrate having a layer of gold plating diffused into the surface thereof. The gold is applied over a nickel strike and the tube is heated within a vacuum furnace to diffuse the gold into the copper surface. The gold diffused inner surface of the tube is found to have superior self-welding characteristics and increased strength and durability. The nobility of the inner surface resists the formation of an oxide coating thereon which eliminates the need to clean the inner surface of the tube before pinch-off. Thus, the entrapment of residual cleaning chemicals within the pinch-off area is avoided.

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Pollock Pines, CA, United States of America

Kenneth L Gustafson