Journal ArticleFrom April 1988 to February 1990 we used a two-level array of scintillators to search in the cosmic radiation for compact sources of y rays above 200 TeV. Counters on the surface measured the size and direction of extensive air showers while counters buried 3 m below ground measured their muon content. Showers induced by y rays are expected to have many fewer muons than those initiated by hadrons so the selection of muon-poor showers should greatly reduce the background of hadronic showers
