The design and performance of a secondary emission electron gun with a wire ionized plasma as an ion source is discussed. An electron beam current density of up to 100 mA/cm2is obtained over an area of 55×5 cm2at a cathode voltage of 250 kV in pulses with a duration of about 20 &mgr;s. The current distribution over the beam area is uniform to better than 25%. The achieved combination of pulse duration, beam current, and electron energy is attractive to excite high‐pressure gas laser media. Preliminary results with the utilization of the gun in an electron beam sustained discharge excited atomic Xe laser show an output energy of 1 J/lat a wavelength of &lgr;=1.73 &mgr;m.