The fundamental characteristics of the energy distribution of output electrons from a single channel electron multiplier were studied experimentally in detail for a few types of straight channels. The width of the energy distribution curve, ranging from about 50 to 15 eV FWHM, is found to depend on the applied voltageVAand the length‐to‐diameter ratio &agr; of the channel, and to vary with output current. The results can be explained in terms of the normalized field strength near the output end of the channel and generalized by a set of universal curves presenting the energy width as a function of output current level for different values ofVA/&agr;.