The results of a study on the pulse-height distributions produced by single primary electrons in proportional counter are discribed. The electrons were liberated at the inner wall by ultraviolet photons offered by a tunable dye laser. The energy of the electrons was slightly larger than the work function of the proportional counter wall material.

Instead of the traditional ultraviolet a laser was used as light source and coincident electronic technique was emploied to eliminate the interference caused by backgrounds. The experiments demonstrated that the pulse-height distribution produced by the single electron with nearly zero kinetic energy was exponential-like when the gas amplification was greater

i.e. the applied voltage on proportional counter was higher.