Reliability optimization for IR detectors with compact cryo-coolers

IR applications are more and more demanding regarding reliability. It is the case of handheld and lightweight UAV applications. To answer these needs, Sofradir and Thales Cryogenics developed a new product family in order to minimize system weight, cost and to increase detector and cooler reliability. Thales Cryogenics has been working on RM integral Stirling cryocoolers since 1995. Then, as a result of several design improvements, it has been possible to increase significantly the efficiency and the reliability of the RM2-Xi cooler over the last 2 years. The RM2-Xi reliability is measured through life time tests which are run continuously on samples taken out from the mass production. Several new tests profiles have been implemented with different climatic and cooler operation conditions. The results gathered enable an accurate evaluation of the cryocooler reliability in the various mission profiles of the customer's applications. Another important performance of an integral cryocooler is efficiency. New mechanical and thermal designs have been implemented. The resulting improvements will be presented and compared with the characteristics of the cryocooler previous version. Based on this new design, Sofradir offers new IR detector products well adapted to handheld and high reliability systems. These new product designs are discussed as well as reliability analysis results.