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Non-Fluid Refrigeration Technology for Cooling Infrared Focal Planes and Other System Components below 50 K in Cryo-Vacuum Test Chambers


OBJECTIVE: Provide a means of cooling infrared focal planes and other system components to their operating temperatures without significant consumption of cryogens. DESCRIPTION: Fluid cryogen delivery systems used in ground testing of space-borne and air-borne imaging systems (such as infrared focal plane arrays using in monitoring projection radiometry) are problematic due to the cost and handling of liquid helium. This systems require significant infrastructure and large amounts of power to cool and store the cryogens. Additionally these systems are wasteful in that large amounts of cryogens are lost to boil-off and other inefficiencies in the system. Furthermore, these systems require Helium to reach the lowest temperatures. Helium is an environmentally limited resource and once lost, cannot be recovered. A reliable technique that does not use cryogenic fluids is needed (such as using magnetic or optical cooling) that can be used to achieve stable device temperatures in the 8 to 60 K temperature range. Such a cooling system must present minimal (<5 milli-g) vibration to the device being cooled. The device should provide a significant power savings over current systems to gain the maximum efficiency and environmental benefit. PHASE I: Demonstrate a prototype non-fluid based closed-circuit refrigerator for use in continuously cooling a cryogenic focal plane array to 30 K with. Temperature control must bewithin +/- 0.1 K. PHASE II: Based on Phase I results, build and demonstrate non-fluid based closed-circuit refrigerator for use in continuously cooling a cryogenic focal plane array to 8 K with . Temperature control must be within +/- 0.1 K. PHASE III: An energy efficient, not cryogenic fluid based system could support an extensive array of military, commercial, and university research programs including laboratory medical, electronic research. REFERENCES: 1. Lowry, H. S., Nicholson, R. A., Simpson, W. R., Mead, K. D., Crider, D. H., and Breeden, M. F.,"Test and Evaluation of Sensor Platforms in the AEDC Space Sensor Test Chambers,"AIAA-2005-7634. 2. Mauritsen, Luke, and Smithgall, Brian,"Cryogenic cooling of optical systems takes many forms", Laser Focus World, January 2011, pp. 95ff. 3."Magnetic Refrigeration", Wikipedia entry, 4. Callier, Maria,"Optical Refrigeration Expected to Enhance Airborne and Spaceborne Apps", 5. Yocum, K. Michael,,"Improvement in Ge Detector Cooling", 2008 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies,
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