LONG-PULSE 250 KEV ELECTRON-GUN FOR HIGH-PRESSURE GAS-LASERS

The design and performance of a secondary emission electron gun with a wire ionized plasma as an ion source is discussed. An electron beam c urrent density of up to 100 mA/cm(2) is obtained over an area of 55x5 cm(2) at a cathode voltage of 250 kV in pulses with a duration of abou t 20 mu s. The current distribution over the beam area is uniform to b etter than 25%. The achieved combination of pulse duration, beam curre nt, and electron energy is attractive to excite high-pressure gas lase r media. Preliminary results with the utilization of the gun in an ele ctron beam sustained discharge excited atomic Xe laser show an output energy of 1 J/l at a wavelength of lambda=1.73 mu m.