| 摘要 |
PURPOSE:To prevent the generation of detrimental current deviation by a method wherein relationship is specified between an angle formed, in a cross section vertical to the direction of laser excitation in a discharge tube, between lines running from the discharge tube center to the two ends of each electrode and the voltage required for the sustenance of discharge in the discharge tube. CONSTITUTION:When 2thetae is the angle formed, in a cross section vertical to the direction of laser excitation in a discharge tube, between two lines running from the center of the discharge tube to both ends of each electrode and K is the ratio of a voltage, which is in presence between electrodes, to a discharge sustaining voltage in the discharge tube, a relationship thetae<=cos<-1>{K<2>/[1.5<2>(K<2>-1)+1]}<1/2> should stand, at least during rated-output operation. The voltage Vop to be applied across electrodes 31 and 41 should be so determined that the rate of the voltage (Vop) to the discharge sustaining voltage dependent upon the inner diameter di of a discharge tube 21 and the pressure of gas present in the discharge tube 21, or the voltage parameter K, may be approximately '1.6'. This effectively removes detrimental current deviation within the discharge tube 21. |
