Cryocooler Systems Demonstration.

TRW successfully transferred Stirling-cycle cryocooler technology from its development at NBS to industry. We installed, modified, and operated a small, plastic, five-stage Stirling cycle refrigerator which was developed at the National Bureau of Standards and furnished to TRW for this project. We also designed and fabricated a new gas handling system, pressure wave generator and displacer drive, and fiber-designed, fabricated, and operated a monolithic thin film SQUID gradiometer on a single silicon chip. The cooler was modified by the addition of a 4 kelvin Joule-Thompson stage before delivery to TRW and we initially fabricated this SQUID with a Nb-Pb technology for 4 kelvin experiments. We later transferred to an all-niobium technology developed at TRW when it was decided to operate the cryocooler at about 7 kelvin without the Joule-Thomson stage. We designed, constructed, and installed all components necessary to interface the magnetometer with the silicon printed circuit board which was heat-sunk to the final stage of the cryocooler. Radiation shields were constructed and low noise and low thermal electrical leads were provided.