A Method of Measuring the Cosmic Ray Charge Composition between 1010 and 1014 eV

We wish to report the details of an experiment to measure the charge composition of the primary cosmic radiation from Z = 1 to about 50 in the energy range 1010 to 1014 eV. A large geometry factor of ~7500 cm2ster is necessary to measure intensities at the low flux levels of these particles. The necessary charge resolution can be obtained using 1/2 m × 1/2 m square detection elements in the following manner. The linearity properties of CsI scintillators and Cerenkov detectors make them ideal for primary charge identification. Further charge information and a fast coincidence pulse will be obtained from two geometry defining plastic scintillators. The fast coincidence pulse will trigger a digitized spark chamber which will provide sufficient directional and positional information so that resolutions comparable with much smaller area detectors can be obtained. The energy of the incident particles is determined using total energy spectrometers. The module for examining electromagnetic cascades consists of six tungsten-scintillator elements, each of one cascade length thickness and each pulse height analyzed. The energy of incident nucleons is measured in the 20 elements of an iron-scintillator ionization calorimeter. It has a total depth of 3.5 nuclear interaction mean free paths.