Monopole, Astrophysics and Cosmic Ray Observatory
MACRO (Monopole, Astrophysics and Cosmic Ray Observatory) was a particle physics experiment located at the Laboratori Nazionali del Gran Sasso in Abruzzo, Italy. A number of universities contributed personnel and equipment, including Boston University and University of L'Aquila.
The primary goal of MACRO was to search for magnetic monopoles. The active elements of MACRO were liquid scintillator and streamer tubes, optimized for high resolution tracking and timing. This design also allowed MACRO to operate as a neutrino detector and as a cosmic ray observatory.
The experiment ceased operating in 2001. No monopole candidates were detected, meaning that the flux of monopoles is less than 5.6×10−15 per square centimetre per steradian per second (cm−2sr−1s−1) for velocities between 0.0001 c and 0.001 c (between 30000 m/s and 300000 m/s).
The magnetic monopole is a theorized particle that has not yet been observed. It is a possible solution to Maxwell's equations. One researcher claimed to have observed a monopole with a light-bulb-sized detector. The fact that a detector the size of multiple football pitches (MACRO) has not yet duplicated this feat leads most to disregard the earlier claim.
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