Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Patent
1999-01-11
2000-08-22
El-Arini, Zeinab
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
134 12, 134 18, 20419234, 20429836, B08B 700
Patent
active
061055891
ABSTRACT:
An improved method and apparatus are provided for cleaning the specimen and interior specimen chamber of Electron Microscopes, and similar electron beam instruments. The apparatus consists of a glow-discharge, oxygen-radical generator placed on a specimen chamber port with an excitation source to create a low-power glow-discharge plasma inside the generator. Air or other oxygen and nitrogen mixture is admitted to the generator at a pressure between 0.3 Torr and 5 Torr. The low power glow discharge is used to disassociate oxygen preferentially over nitrogen to create the oxygen radicals. The oxygen radicals then disperse by convection throughout the chamber to clean hydrocarbons from the surfaces of the chamber, stage and specimen by oxidation to CO and H.sub.2 O gases. The excitation power of the plasma is limited to limit the nitrogen ion production that destroys the oxygen radicals and to limit the projection of the electrically active plasma into the specimen chamber. The optical emission or color of the plasma is observed for the selection of the correct power level for maximum oxygen radical production.
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