| 摘要 |
PURPOSE:To provide a discharge electrode in which an optimum thickness for maintaining a stable glow discharge can be formed by releasing an inner dielectric element from an external pressure by supporting the pressure due to a pressure difference by an outer dielectric element. CONSTITUTION:Windows 1a provided at walls of opposed surfaces disposed at both sides of a discharge space (a) of a vacuum vessel 1 are hermetically sealingly blocked by outer dielectric elements 3A, 3B having a recess 3a, inner dielectric elements 4A, 4B are provided at its inside so as to form a space (b) by covering the recess with covers, cooling blocks 6A, 6B are fixed to the bottom of the recess in the space (b), and metal electrodes 8A, 8B to be brought into pressure contact with the blocks by a spring 8 and with the inner dielectric elements by a spring 11 are provided. Further, the pressure of the space is set to the same pressure as that in the vessel via a communication hole 5, and a high frequency voltage is applied to the metal electrodes through a tube 7, the blocks. |
