| 摘要 |
PURPOSE:To realize uniform preionization along the whole length of a discharge region and make laser output stable by disposing preionization electrodes in a staggered manner and by disposing auxiliary preionization electrodes at positions deviated from end parts of the discharge region along the optical axis direction. CONSTITUTION:Upper preionization electrodes 6 that are disposed at one side and the other side of a cathode 3 are disposed in a staggered manner in a state that the electrodes do not face each other by shifting them in the optical axis direction and, or both sides of an anode 4, lower preionization electrodes 8 are disposed so that they correspond to the upper preionized electrodes 6. Further, a pair of upper and lower auxiliary preionization electrodes 6a and 8a are disposed at a pitch (p) that has almost the same disposition space as that of respective electrodes 6 and 8 on one side of a position deviated from both ends of a discharge region (h) that locates along the optical axis directions of the cathode 3 and anode 4. Thus almost uniform preionization is realized all over the discharge region that locates along the optical axis directions of the cathode 3 and anode 4. |
