Monte Carlo Calculations of Atmospheric Electrons Compared with Data from HEAT

Abstract

The GEANT/FLUKA detector simulation and particle interaction package was used to develop a Monte Carlo program to estimate atmospheric secondary flux produced by primary cosmic rays, as a function of depth in the atmosphere. Of special interest is the calculation of secondary electrons and positrons near the top of the atmosphere. The HEAT instrument measured primary and secondary electrons ranging in energy from 500 MeV to 50 GeV during a high altitude balloon flight during May, 1994 from Ft. Sumner, New Mexico. It is assumed that electrons with rigidities below geomagnetic cutoff consist of both secondary and reentrant albedo electrons. The MC calculations are compared to the flux of secondary electrons as measured by the HEAT instrument. 1 Introduction Despite better measurements of primary cosmic ray spectra and interaction cross sections during the last 30 years, calculations of atmospheric secondaries still differ by as much as a factor of two. In order to correct for atmospheri..