SUPERCONDUCTIVE DEVICES FOR NONDESTRUCTIVE TESTING

WE PROPOSE TO INITIATE DEVELOPMENT OF THREE NON-CONTACTING SUPERCONDUCTIVE ELECTROMAGNETIC SYSTEMS FOR NONDESTRUCTIVE TEST AND EVALUATION APPLICATIONS. TWO SYSTEMS USE SQUID GRADIOMETERS AND SUPERCONDUCTIVE MAGNETIZING COILS. ONE IS SUITED TO TESTING FLAT METAL METAL FOILS, SHEETS, OR PLATES. THE OTHER IS DESIGNED FOR TESTING TUBING, PIPES, AND RODS. THE THIRD PROPOSED SYSTEM CONSISTS OF A SINGLE SUPERCONDUCTING COIL. IT IS THE SUPERCONDUCTIVE ANALOG TO CONVENTIONAL EDDY CURRENT FLAW DETECTION SYSTEMS. SUPERCONDUCTIVE SYSTEMS OFFER GREAT IMPROVEMENTS IN SENSITIVITY AND SPATIAL RESOLUTION OVER CONVENTIONAL MAGNETIC AND ELECTROMAGNETIC NDE SYSTEMS. FURTHERMORE, THEIR UNMATCHED SENSITIVITY AT FREQUENCIES OF A FEW HERTZ EXTEND THE USABLE PENETRATION DEPTH BY NEARLY TWO ORDERS OF MAGNITUDE OVER THAT OFFERED BY PRESENT-DAY SYSTEMS. PROTOTYPE SYSTEMS TO BE FABRICATED AND TESTED IN PHASE II WORK USE LIQUID HELIUM TEMPERATURE SUPERCONDUCTORS. NONETHELESS, THE RECENTLY DISCOVERED CLASS OF LIQUID NITROGEN TEMPERATURE SUPERCONDUCTORS OFFERS THE PROMISE OF CONVENIENT AND ECONOMICAL SUPERCONDUCTING NDE SYSTEMS.