A Search for Successive Air Showers with the Same Arrival Direction

A search is been making for successive air showers induced by >0.1 PeV energy gamma-ray bursts by the Kinki University Extensive Air Shower Array. A new method is proposed for data analysis of the search for successive air showers arriving with the same arrival direction in short interval time using right ascension vs. declination plots. Some "excess" around the right ascension 5 and 20 hour is found in a sample of 50k events during five months since December 1989. However, at the present stage, we cannot deny that it may be caused by background fluctuation. We should use more reliable data in following experiments.