VIBRATION DETECTORS USING MAGNETIC SUSPENSION VIA HIGH TEMPERATURE SUPERCONDUCTORS

THERE EXISTS A NEED FOR INEXPENSIVE, LOW FREQUENCY (0.001 HZ TO 50 HZ) ULTRASENSITIVE VIBRATION DETECTORS. RUGGEDNESS, STABILITY, DYNAMIC RANGE, SENSITIVITY AND COST ALL COMBINE TO LIMIT IN ONE WAY OR ANOTHER THE USE OF CONVENTIONAL DEVICES. RECENT RESEARCH WITH THE NEW CLASS OF HIGH TEMPERATURE CERAMIC SUPERCONDUCTORS AND WITH EDDY CURRENT DISPLACEMENT GAUGES HAS PROVIDED A NEW APPROACH TO THESE VIBRATION DETECTORS. THE MEISSNER EFFECT CAN BE USED TO LEVITATE SMALL MAGNETS ABOVE A SPECIALLY SHAPED SUPERCONDUCTOR (SUCH AS YBA(2)CU(2)O(6.5) AT 77 DEG K) AND AN EDDY CURRENT DEVICE CAN BE USED TO DETECT THE MOTION OF THIS MAGNET IN RESPONSE TO DISTURBANCES. BECAUSE THE LEVITATION IS ESSENTIALLY "FRICTIONLESS", AND BECAUSE EQUILIBRATION SHOULD BE VERY RAPID, DRIFT MIGHT BE ALMOST NONEXISTENT IN SUCH INSTRUMENTS. PRELIMINARY INVESTIGATIONS INDICATE THAT SUCH SYSTEMS SHOULD BE LOW COST, VERY RUGGED DURING TRANSPORT AND SETUP, AND HAVE SUFFICIENT BANDWIDTH, DYNAMIC RANGE AND SENSITIVITY TO COMPETE FAVORABLY WITH CONVENTIONAL DETECTORS. THE ADVENT OF SUCH ULTRASENSITIVE DEVICES COULD GREATLY FACILITATE MONITORING OF LOW FREQUENCY VIBRATION, PERHAPS FORMING THE NUCLEUS OF A VERY SENSITIVE DRY SIDE SONAR DETECTION SYSTEM.