Time Structure of Cosmic-Ray Showers

Abstract

The time structure of extensive air showers at sea level has been measured by coincidence of liquid scintillation detectors and auxiliary Geiger tubes. The standard time deviation relative to the mean of single electrons is found to be 2\ifmmode\pm\else\textpm\fi{}2 m\ensuremath{\mu} sec; the same quantity for single particles capable of penetrating 20 cm of Pb is 6\ifmmode\pm\else\textpm\fi{}2 m\ensuremath{\mu} sec. The mean delay of penetrating particles relative to electrons is 0.9\ifmmode\pm\else\textpm\fi{}1.3 m\ensuremath{\mu} sec.