| 摘要 |
PURPOSE:To stabilize the discharge position by a method wherein, within the laser system composed of a chamber in airtight structure longer in the axial direction and a pair of opposite electrodes extending in the axial direction in the chamber, multiple projections are formed on the cathode surface of one opposite electrode. CONSTITUTION:A pair of opposite electrodes 2a, 2b is arranged in the space of a chamber 1, the upper side electrode 2a has conventional flat surface while the lower side electrode 2b has multiple projections 3 on the opposite surfaces. The projections 3 are provided with spherical heads having the crest thereof in relatively flat and small area as well as the gradually rising up circular truncated conical part around the same 3. At this time, the power lines from the upper side electrode 2a to the lower side electrode 2b are firstly concentrated on the vertexes of the protrusions 3. When the current flowing between the opposite electrodes 2a, 2b is increased, the discharge (D) is expanded from the crest parts to the lower parts not to be expanded in the lateral direction. Accordingly, the discharge region (D) can be stabilized. |
