Flux Limit on Cosmic-Ray Magnetic Monopoles from a Large Area Induction Detector

Abstract

The design and performance of a superconducting induction detector with two 60-cm-diam superconducting loops is presented. During eight months of data taking, no candidate events were observed and an upper limit on the flux of cosmic-ray magnetic monopoles $F_m\lesssim 6.7\times {10}^{-12\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{sr}}^{-1\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ (90% C.L.) is set. The detector demonstrates the possibility of operating large induction detectors in ambient magnetic fields greater than 1 mG.