CALCULATED ELECTRON-FLUXES AT AIRPLANE ALTITUDES

A precision measurement of atmospheric electron fluxes has been perfor med on a Japanese commercial airliner (Enomoto et al.). The bulk of th ese electrons are produced in pairs from the gamma rays emitted when p i0's decay, which in turn have been produced in cosmic-ray-air-nucleus collisions. These electron fluxes can be used to test elements of our atmospheric neutrino flux calculation, i.e., the assumed primary spec trum and the Monte Carlo shower code. Here we have modified the Monte Carlo program which had previously been used to calculate the fluxes o f atmospheric neutrinos by combining it with the program GEANT to comp ute the electromagnetic part of the shower. This hybrid program now ke eps track of the electrons produced in cosmic-ray showers as a functio n of energy and atmospheric depth. We compare our calculated integral fluxes above the experimental threshold energies 1, 2, and 4 GeV for a variety of atmospheric depths and cutoff rigidities. Our results are in good agreement (approximately a few %) with the data, but we found we needed to boost the normalization of the primary flux by 12% over t he value we had previously used to calculate the atmospheric neutrino flux.