Impedance of a UV preionized excimer laser

摘要

This paper reports the behavior of an XeCl laser having two independent preionizers which generate UV radiation into the discharge region in the perpendicular and parallel direction to the electrode surfaces. Output energy and other parameters have been measured using a single preionizer and both preionizers, changing the power-supply polarity and varying the delay time between the preionization and the main discharge. When the preionization system generated photons only in the direction perpendicular to the electrode surfaces and a negative power supply was used, a high discharge current and a high output laser energy were obtained. Besides, the diffusion coefficient of the photo-preionized electrons played an important role in the laser behavior, particularly when a consistent delay time between the onset time of the preionization and the main discharge was present. During the breakdown the discharge impedance is time dependent and its value changes as the preionizers change position. By comparing the experimental results obtained by the equation of the discharge electric circuit, it is possible to get exactly the electric element value which simulates the discharge impedance.