Field Emission Microscopic Observation of Effects of Oxygen or Air on the High Temperature Tungsten Cathode

概要

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By using Muller-type field emission microscope with an ordinary pumping system, effects of gas introduction and filed desorption on a carbon-adsorbed tungsten surface are examined at high temperatures around 1500°K. The removal of carbon from the tungsten surface is verified when a very small quantity of oxygen or air is introduced into the tube. The carbon-adsorption on the tungsten surface caused by the decomposition of vacuum oil on the tip under the conventional operating condition is observed successively during the process. From the results, it is found that the change in the 011 and the 111 regions is always regular, but in the 001 region it is very complicated. The field desorption effect on the carbon-adsorbed tungsten surface is also observed, and the same change as obtained in the gas introduction is found in the 001 region.
東北大学の論文