Abstract: A pressure relief valve having two rigid sealing surfaces lapped to a smoothness Ra of 8 micro-inches or less, and flatness within 80 micro-inches, forms a reliable seal by direct contact therebetween without an elastomer. The sealing surfaces and surrounding structures can be made of one or more metals, such as alloys of stainless steel, and can be CTE-matched, so that the valve is not impeded by environmental temperature changes. In a disclosed embodiment, a “poppet” is axially pressed against a seal plate by a spring. The poppet can be axially stabilized by sliding within a surrounding cylinder or spacer, and can contact the surrounding surface with a plurality of “arms” that reduce friction and enable gas flow therebetween. The poppet can be made from anti-galling Nitronic 60 alloy, and the surrounding structures can be stainless steel. Embodiments are suitable for low-pressure gas applications in extreme environments.

Abstract: A pressure relief valve having two rigid sealing surfaces lapped to a smoothness Ra of 8 micro-inches or less, and flatness within 80 micro-inches, forms a reliable seal by direct contact therebetween without an elastomer. The sealing surfaces and surrounding structures can be made of one or more metals, such as alloys of stainless steel, and can be CTE-matched, so that the valve is not impeded by environmental temperature changes. In a disclosed embodiment, a “poppet” is axially pressed against a seal plate by a spring. The poppet can be axially stabilized by sliding within a surrounding cylinder or spacer, and can contact the surrounding surface with a plurality of “arms” that reduce friction and enable gas flow therebetween. The poppet can be made from anti-galling Nitronic 60 alloy, and the surrounding structures can be stainless steel. Embodiments are suitable for low-pressure gas applications in extreme environments.

Abstract: A thermal coupler assembly mounted to the coldfinger of a cryogenic cooler which provides improved thermal transfer between the coldfinger and the detector assembly mounted on the dewar endwell. The thermal coupler design comprises a stud and spring-loaded cap mounted on the coldfinger assembly. Thermal transfer is made primarily through the air space between the cap and coldwell walls along the radial surfaces. The cap is spring loaded to provide thermal contact between the cap and endwell end surfaces.