DEVICE FOR PRE-IONIZATION IN DISCHARGE-PUMPED GAS LASERS, IN PARTICULAR FOR X-RAY PRE-IONIZATION

摘要

Preionization is important for the generation of a homogeneous glow discharge in the gas space of a laser chamber between laser electrodes. TE type excimer lasers operate especially with X-ray preionization, for which high voltage pulses are needed. According to the present invention, the voltage pulses are obtained by means of an auxiliary circuit that includes a branch which is connected in parallel with a high voltage switch or with the laser discharge gap and which incorporates a saturable magnetic inductance and the primary winding of a high voltage pulse transformer connected in series therewith. The high voltage triggering pulses for the preionization element, which is an X-ray tube in particular, are generated in the secondary winding of the transformer. If the branch is connected in parallel with the high voltage switch it also has a series capacitor. If it is in parallel with the laser discharge gap then the branch has a shunt capacitor. In this way, the timing of the preionization and in particular the X-ray pulse, can be adjusted precisely in relation to the voltage rise time through the laser electrodes and in relation to the laser.