Electron-proton separation in calorimetry experiments directly measuring the composition and energy spectrum of cosmic rays

Calorimetric particle detectors that play an important role in high-energy cosmic-ray balloon and satellite experiments have not only the major task of measuring energy but also face the problem of identifying electrons from protons. This problem is usually solved by measuring the longitudinal, traverse shower profile and the total energy release in the calorimeter, using the fact that electromagnetic and hadronic showers differ in their spatial and energy distribution. In this paper, proton and electron identification methods for different types of calorimeters used in cosmic-ray balloon- and satellite-borne experiments are discussed.