LOCATING DEEPLY BURIED ORDNANCE

OPTICALLY PUMPED MAGNETIC DETECTORS ARE CURRENTLY USED IN MILITARY APPLICATIONS TO DETECT BURIED ORDANANCE AND UNDERWATER MINES, BUT EXISTING INSTRUMENTS HAVE LIMITED SENSITIVITY. DR WILLIAM HAPPER HAS SUGGESTED THAT OPTICALLY PUMPED SENSORS CAN BE DRAMATICALLY IMPROVED AND MIGHT ULTIMATELY PROVIDE A SENSITIVITY COMPARABLE TO TO THAT OF SUPERCONDUCTING GRADIOMETERS. IN THIS PROPOSAL WE OUTLINE PRELIMINARY EXPERIMENTS WHICH SHOULD DEMONSTRATE THE FEASIBILITY OF CONSTRUCTING A FREE PRECESSION, OPTICALLY PUMPED MAGNETIC DETECTOR SUCH AS HAPPER DESCRIBES. PHASE I WILL ADDRESS THE CRITICAL PROBLEMS OF ABSORPTION CELL WALL COATING, THE DEPHASING OF THE COHERENT LARMOR PRECESSION, AND THE DETECTION OF THEAN IMPROVED OPTICALLY PUMPED MAGNETIC DETECTOR FOR LOCATING DEEPLY BURIED ORDNANCE LARMOR FREQUENCY IN A FREE PRECESSION SYSTEM.THE FINAL PART OF PHASE I WILL BRIEFLY EXAMINE THE ENGINEERING PROBLEMS OF PRODUCING A HIGH INTENSITY OPTICAL PUMPING BEAM, A COMMON-SOURCE DETECTING BEAM, AND THE ELECTRONIC SIGNAL PROCESSING SYSTEM. THE FINAL REPORT WILL COMBINE THIS DATA INTO A PRELIMINARY CONCEPTIONAL DESIGN FOR A PROTOTYPE INSTRUMENT.