| 摘要 |
PURPOSE:To stabilize the state of discharge, by attaching the base end part of each planar cathode to a discharge wall, and making the distance between the tip part of each electrode and the tip part of an anode to be the shortest distance at least at one position. CONSTITUTION:Each cathode 11 is formed with a plate, which is in parallel with a laser gas stream 19. The parallel planar base end part of each cathode 11 is bent at about a right angle with respect to the laser gas stream 19 and attached to a discharge wall 13 with a bolt 21. At the U shaped planar tip part of each cathode 11, which is in parallel with the laser gas stream 19, cut parts 27 are formed at, e.g., a plurality of positions in a slant shape, along the direction of the laser gas stream 19. The cut parts 27 form a sawtooth shape. The distance between each planar cathode 11, which is in parallel with the laser gas stream 19, and an anode 9, is made to be the shortest distance at the most upstream side of the laser gas stream 19. The laser gas, which is ionized by the discharge at the most upstream side, is made to flow toward the downstream. Thus the discharge at the downstream side is made easy. Therefore, the discharge state is stabilized, and the stability of the laser output becomes excellent. |
