A RARE-EARTH CRYOGENIC PROJECTOR USING HIGH-TC SUPERCONDUCTORS

A RARE-EARTH, MAGNETOSTRICTIVE, MATERIAL, TB(X)DY(1-X) (0.50.6), OPERATING AT CRYOGENIC TEMPERATURES, CAN STORE AND RELEASE TWENTY TIMES THE ENERGY OF PIEZOELECTRIC MATERIALS, AND FIVE TIMES THE ENERGY OF THE BEST ROOM-TEMPERATURE, MAGNETOSTRICTIVE, RARE-EARTH ALLOYS. THIS MAKES IT IDEAL FOR THE CONSTRUCTION OF LOW-FREQUENCY, HIGH-POWER, UNDERWATER, ACOUSTIC PROJECTORS. BROAD-BAND, LOW-Q, PROJECTOR APPLICATIONS ARE LIMITED BY THE AC ELECTRICAL DRIVE AND THE DC BIAS FIELDS. THE LOW LOSSES INHERENT IN HIGH-T(C) SUPERCONDUCTORS CAN SIGNIFICANTLY REDUCE THE POWER REQUIREMENTS AND INCREASE OVERALL EFFICIENCY. IN THIS SBIR WE PLAN TO: 1. DEMONSTRATE A RARE EARTH TB(X)DY(1-X) TRANSDUCER DRIVEN BY A SUPERCONDUCTING COIL AND OPERATED AT LIQUID NITROGEN TEMPERATURES. 2. MEASURE PERFORMANCE WITH A SUPERCONDUCTING COIL AND A COMPARISON COPPER COIL. 3. DETERMINE IF A SUPERCONDUCTING-COIL TRANSDUCTION DEVICE CAN BE DESIGNED FOR USE OPERATING BELOW 500 HZ WITH ACOUSTIC POWER OUTPUT EXCEEDING 4 KW AND WITH AT LEAST 70% EFFICIENCY. 4. EXTRAPOLATE ELECTRICAL EFFICIENCY FOR THE CASE OF AN ARRAY-LOADED, TRANSDUCER OPERATED AT RESONANCE BASED ON THE DATA DERIVED FROM THE EXPERIMENTS. 5. DERIVE RESISTIVE INDUCTIVE AND MAGNETOSTRICTIVE "D" CONSTANT VALUES FROM THE MEASUREMENTS.