| 摘要 |
PURPOSE: To lower a cathode voltage drop, to improve thereby the efficiency of a laser tube and to enable absorption of distortion of the laser tube or the like due to discharge heating, by a method wherein a cathode disposed opposite to an anode in formed to be cylindrical and this cathode is fitted along the direction of the tube axis of a thin tube part. CONSTITUTION: An indirectly heated cathode 30 is formed to be hollow and cylindrical out of a material prepared by impregnated pores of a porous tungsten sintered compact with a barium compound. This cathode 30 is so formed that the inside diameter is within the range of 1 to 10 times larger than that of a thin tube part 2, e.g. identical with it. The cathode 30 is fitted in proximity to the thin tube part 2 and along the direction of the tube axis of this part. When a voltage being equal to or higher than a discharge maintaining voltage is impressed between this cathode 30 and an anode 6, an arc discharge is generated between these cathode 30 and anode 6, optical resonance is generated between Brewster windows 3 and 4 by the arc discharge and a laser light is outputted. |
