| 摘要 |
PURPOSE:To enable pre-ionization and primary discharge to be smoothly carried out by a method wherein the diameter of a part of a pre-discharge electrode opposed to a primary electrode is so set as to make the electric field of the part concerned lower than the discharge electric field of gas laser medium in intensity, and the diameter of the tip of the pre-discharge electrode is made smaller than that of its part opposed to the primary electrode. CONSTITUTION:The diameter of a part of a pre-discharge electrode 6 opposed to primary electrodes 2 and 3 is made large enough so as to make the electric field of the part concerned lower than the discharge electric field of mixed gas 1 in intensity. The diameter of the tip of the pre-discharge electrode 6 is made much smaller than that of its part opposed to the primary electrode. That is, the part of the pre- discharge electrode 6 opposed to the primary electrodes 2 and 3 are formed large in diameter, whereby an electric field 10 of the opposed part becomes low in intensity and consequently voltage withstanding strength between the pre-discharge electrode 6 and the primary electrode 3 is sharply improved. On the contrary, the opposed parts of the pre-discharge electrodes 6 or the tips of the electrodes 6 are formed small in diameter, so that discharge starts easily between the pre-discharge electrodes 6. By this setup, pre-ionization and primary discharge following it are smoothly and stably carried out. |
