A study of the `total voltage´ effect

An electron spectroscopy technique, employing a plane-parallel electrode geometry with an anode probe hole has been used to make a detailed study of how the Fowler-Nordheim plot of a single emission site varies with gap separation d. After correction for the gap field in the vicinity of the probe hole, it has been established that the field enhancement or β factor of the site does not in fact exhibit a dependence on the total gap voltage over the range 0.4≲ d≲1.0 mm. The findings of this study provide no evidence to support the existence of a total-voltage effect, i.e., the effect of taking account of the nonuniformity of the gap introduced by the presence of an anode probe hole. This conclusion is qualified by recognizing that the range of gap spacings investigated was, for technical reasons, relatively restricted. However, this disadvantage is partially offset by the intrinsic accuracy of the measurements