M. Ambrosio et al., COINCIDENT OBSERVATION OF AIR CERENKOV LIGHT BY A SURFACE ARRAY AND MUON BUNDLES BY A DEEP UNDERGROUND DETECTOR, Physical review. D. Particles and fields, 50(5), 1994, pp. 3046-3058
We report on the simultaneous observation of atmospheric Cerenkov ligh
t by a prototype five telescope array, GRACE (Gran Sasso Air Cerenkov
Experiment) with deep underground muons in the MACRO (Monopole Astroph
ysics and Cosmic Ray Observatory). The telescope array was deployed at
Campo Imperatore above the Gran Sasso Laboratory for a run completed
in the fall of 1992. The total live time for the combined surface-unde
rground operation was similar to 100 h during which more than 300 even
ts were seen in coincidence. The efficacy of this technique to monitor
the electromagnetic and penetrating muon components of a cosmic-ray-i
nduced cascade is discussed.