1999A&AS..138..599C

INCA is an air shower array located at Mount Chacaltaya in Bolivia, at 5200 m a.s.l., searching for Gamma Ray Bursts of energy E>1 GeV. The results presented here concern a GRB search made in correlation with 70 events recorded by BATSE since December 1996 to August 1998. For every burst, the INCA counting rate has been studied both during the BATSE detection time and in 2 hours around. No significant excess has been found in any of the trials. Assuming for the burst a power low energy spectrum extending up to 1TeV with a slope α=-2 and a time duration of 10s, the obtained 1GeV/1TeV energy fluence upper limits range from 5.3x10^–5erg/cm² to 2.9x10^–2erg/cm² depending on the event zenith angle.