The intensity of low-energy events in the cosmic radiation has been examined as a function of altitude with an energy gated scintillation counter. Events selected were those giving pulses the equivalent of 0.2-Mev to 2.0-Mev electron energy loss in the scintillation crystal. Compared with data for total radiation, the present results show a shift toward lower altitudes by an almost constant fraction of a radiation length.

• Received 6 May 1954

DOI:https://doi.org/10.1103/PhysRev.95.1294