Cosmic-ray electrons and positrons from 1 to 100 GeV: Measurements with heat and their interpretation

Measurements of the spectra of negative electrons and positrons have been p erformed with the High-Energy Antimatter Telescope (HEAT) in two balloon fl ights-1994 May from Fort Sumner, NM, and 1995 August from Lynn Lake, Manito ba. We present the combined data set from these two flights, covering the e nergy range 1-100 GeV. We compare our data with results from other groups a nd discuss the data in the context of diffusive propagation models. There i s some evidence that primary electrons above 10 GeV and cosmic-ray nuclei e xhibit the same energy spectrum at the source, but that the source spectrum becomes harder at lower energy. Within the experimental uncertainties, the intensity of positrons is consistent with a purely secondary origin, due t o nuclear interactions in interstellar space.