LAAS network observation of air showers

A network observation of air showers is in progress in Japan. Researchers f rom 10 institutions are taking part in the network, forming the Large Area Air Shower (LAAS) group. As of June 2000, eight air shower arrays (stations ) are in operation, while five more stations are under construction. The st ations are scattered over an enormous area of 130,000 km(2), however the Gl obal Positioning System (GPS) provides comparable time stamps among them wi th an accuracy of one microsecond, The aim of the network is to find out co rrelations in primary cosmic rays just below the knee. The data from the pl anned Norikura array (2,770 m a.s.l.) is expected to reveal new aspects of correlated cosmic rays. The current status of the network and performance o f arrays calculated by the air shower simulation code CORSIKA are described here.