SQUID NMR FOR EXPLOSIVES DETECTION

THE SUCCESS OF PREVIOUS CONVENTIONAL NUCLEAR MAGNETIC RESONANCE (NMR) AND NUCLEAR QUADRUPOLE RESONANCE (NQR) SYSTEMS FOR DETECTING EXPLOSIVES IN AIRLINE BAGGAGE HAS BEEN LIMITED BY THE NEED TO OPERATE AT LOW FIELDS AND LOW FREQUENCIES WHERE THE SENSITIVITY OF SUCH SYSTEMS IS SEVERELY LIMITED. HOWEVER, RECENT EXPERIMENTS HAVE SHOWN THAT SUPERCONDUCTING DEVICES IN NMR DETECTION CIRCUITS CAN ACHIEVE HIGH SENSITIVITY AT LOW FREQUENCIES, AND THIS RESULT SHOULD ALSO BE TRUE FOR NQR SYSTEMS. COUPLED WITH THE DISCOVERY OF SUPERCONDUCTING MATERIALS WHICH CAN OPERATEAT TEMPERATURES READILY AVAILABLE WITH MECHANICAL REFRIGERATION SYSTEMS, THIS WORK OFFERS THE POSSIBILITY OF SIGNIFICANT IMPROVEMENTS IN MAGNETIC RESONANCE EXPLOSIVES DETECTION SYSTEMS.