The response of Los Cerrillos detectors to the 1989/90 GLE events

Abstract

During the ascending solar-activity phase of Schwabe cycle N.22 eleven ground-level enhancements (GLEs) have been registered by the ground-based network of cosmic-ray detectors. They are: July 25, August 16, September 29, October 19, 22 and 24, November 15, 1989 and May 21, 24, 26 and 28, 1990 (i.e., they all have been recorded within a year interval - after a pause of about five years). Data obtained in Chile (Santiago: "Los Cerrillos"; geographic coordinates: 330 27'S, 70031'W; height: 570 m) with the standard neutron monitor (6 - NM - 64) and the multidirectional muon telescope are presented for these unusual events.