Abstract: The Ar atomic excitated voltage are studied from the experiment in different parameter, and the experimental curve are analyzed; The optimum parameter are the filament voltage is 3.2 V, the grid voltage is 1.0 V and the spurn voltage is 10.0 V are brought forward to use the F-H experiment. The first excitated ex- plode voltage of Ar is 11.6 V. The result shows the value should be the first sub-tranquilization excitated voltage, or the two sub-tranquilization probability ratio.

Key words: F-H experiment, first excitated voltage, energy quantum effect, sub-tranquilization state