A STIRLING CRYOCOOLER FOR MRI CRYOSTAT SHIELD COOLING

STIRLING TECHNOLOGY COMPANY (STC) WILL DEVELOP AND DEMONSTRATE A TWO-STATE FREE-PISTON STIRLING CYCLE CRYOCOOLER THAT IS ENERGY EFFICIENT, EXTREMELY RELIABLE, PRODUCES NEGLIGIBLE VIBRATION AND NOISE, REQUIRES MINIMAL MAINTENANCE, AND IS OF SUFFICIENT CAPACITY TO MEET PRESENT AND FUTURE MAGNETIC RESONANCE IMAGING (MRI) CRYOSTATE SHIELD COOLING REQUIREMENTS. RELIANCE UPON COMMERCIALLY AVAILABLE GIFFORD MCMAHON CRYOCOOLERS HAS RESULTED IN LIMITED COOLING CAPACITY, EXCESS VIBRATION, AND LESS THAN DESIRED RELIABILITY. EXCESS VIBRATION REDUCES IMAGE RESOLUTION AND IS EXPECTED TO BECOME MORE CRITICAL IN FUTURE SYSTEMS. STC WILL ACHIEVE THE DESIGN GOALS BY INCORPORATING FLEXURAL BEARINGS, NON-CONTACTING CLEARANCE SEALS, FREE-PISTON DISPLACER DYNAMICS, A LINEAR MOTOR DRIVEN COMPRESSOR, AND AN ACTIVE VIBRATION ABSORBER. SUCCESSFUL DEVELOPMENT OF THIS CRYOCOOLER WILL RESULT IN LOWER OPERATING COSTS FOR MRI SYSTEMS DUE TO IMPROVED CRYOGEN CONSERVATION, REDUCED MAINTENANCE, AND LOWER ELECTRICAL POWER CONSUMPTION.