A pulsed gas discharge laser operating at an output laser pulse repetition rate of greater than 4 kHz and a method of operating same is disclosed which may comprise a high voltage electrode having a longitudinal extent; a main insulator electrically insulating the high voltage electrode from a grounded gas discharge chamber; a preionizer longitudinally extending along at least a portion of the longitudinal extent of the high voltage electrode; a preionization shim integral with the electrode extending toward the preionizer. The preionizer may be formed integrally with the main insulator. The preionization shim may substantially cover the gap between the electrode and the preionizer. The apparatus and method may comprise the high voltage electrode being disposed in an electrode receiving pocket in the main insulator and formed to present an elongated discharge receiving area facing another electrode within the gas discharge chamber, an aerodynamic fairing attached to the high voltage electrode and substantially closing the gas flow disturbance pocket and presenting an aerodynamically smooth surface to the gas flow.