The IBM monopole experiments

Conventional superconducting magnetometers used for monopole detection must be operated in an extremely stable, low field environment. This places a severe restriction on the cross sectional area of such detectors. In addition, the geometry of these detectors does not easily permit coincidence operation with other particle detectors. Gradiometer monopole detectors developed at IBM permit a significant relaxation of the constraint on the stability of the magnetic field, and on the geometry of the detector. A prototype detector consisting of two 100 cm/sup 2/ loops operated in coincidence has been constructed and operated successfully in a milligauss environment. No events consistent with a monopole have been observed in 95 days of operation. A larger detector is now being fabricated