The mid-IR detectors must operate at 7K to detect thermal emissions at wavelengths out to 29 microns. A high-efficiency pulse-tube cryocooler is being developed to provide this cooling capability. The Webb cryocooler is unique in that it provides cooling remotely: the cold head is close to the mid-IR detectors which are located approximately 20 meters from the cryocooler compressor and electronics.
A three year technology demonstration program has already proven the remote cooling capability. Further testing on a bread-board system has shown that the cooler is capable of cooling the detectors to required 7K operating temperature.