Discharge excitation gas laser apparatus

A discharge excitation laser apparatus comprising:

• a pair of first and second primary electrodes disposed in, a spaced opposed relation with respect to each other and having a main discharge spaced defined therebetween;
• an excitation circuit connected to said first and second primary electrodes for causing a main discharge therebetween to thereby generate laser oscillations of a laser gas in the main discharge space;
• preionization means for preionizing the laser gas in the main discharge space prior to the main discharge between said first and second primary electrodes;
• and
• preionization timing setting means for setting a time when preionization is triggered including a means for establishing a minimum discharge starting voltage between said first and second primary electrodes, and a means for using the established voltage to determine the preionization trigger time.

A discharge excitation laser apparatus comprising:

• a pair of first and second primary electrodes disposed in a spaced opposed relation with respect to each other and having a main discharge spaced defined therebetween;
• an excitation circuit connected to said first and second primary electrodes for causing a main discharge therebetween to thereby generate laser oscillations of a laser gas in the main discharge space;
• preionization means for preionizing the laser gas in the main discharge space prior to the main discharge between said first and second primary electrodes;
• and
• preionization timing setting means for setting a time when preionization is triggered including a means for establishing a minimum time between the time a high voltage is applied between said first and second primary electrodes and the time the main discharge starts, and a means for using the established time to determine the preionization trigger time.