USE OF A NEUTRINO DETECTOR FOR MUON IDENTIFICATION BY THE CYGNUS AIR-SHOWER ARRAY

The muon content of extensive air showers observed by the CYGNUS experiment are measured by a well-shielded apparatus. originally used for accelerator neutrino detection. Primary identification and counting of muons relies on a 44 m2 array of multiwire proportional counters that has operated continuously since the experiment's inception to the present time. During the experiment's first 20 months, the central detector, consisting of flash-tube chambers, was used for high-resolution reconstruction of muon trajectories for a limited subsample of air showers. The ability to distinguish individual muons in the tracking device enabled verification and calibration of the muon counting by the proportional-counter system. The tracking capability was also used to verify the systematic pointing accuracy of the extensive air-shower arrival direction, as determined by the CYGNUS array, to better than 0.5-degrees.