Abstract: In a gas ion laser of the type having a serial array of coaxially aligned axially spaced floating electrodes contained within an evacuable dielectric envelope for exciting a d.c. plasma laser pumping discharge, the electrodes and gas fill are cooled by a plurality of axially directed coolant tubes within the gas-filled envelope. The electrodes have a spherically shaped funnel portion immediately surrounding the laser beam and plasma discharge path for focusing secondary electrons back into the beam path for increasing conversion efficiency. The spherically shaped surfaces are electroplated with a tungsten-cobalt alloy to decrease sputter erosion.