Observation of the cosmic ray electron-positron ratio from 100 Mev to 3 bev in 1964

Abstract

A determination of the charge ratio of the primary cosmic ray electrons provides important evidence for the origin of the electron c,Gmponent.In 1963 DeShong, Hildebrand and Meyer (DeShong, et al, 1964a) reported the results of an experiment designed to measure this ratio in the energy interval from 100 to 1000 MeV.They found an excess of negative electrons which led them to conclude that the electron component consists mainly o f directly accelerated particles.Their data gave an upper l i m i t for the contribution of electrons and positrons which are produced by protonproion collisions i n the galaxy.In this note we present further results from an experiment carried out at balloon altitude over Ft.Churchill, and using the same basic equipment (DeShong, et al, 1964b)modified for better energy resolution.Although the new data are of poorer statistical accuracy than those of 1963 they do extend the energy range of the -measurement.A schematic diagram of the instrument i s shown in Fig. 1.A counter telescope defines a beam of vertically incident particles passing through the gap of