Pumping of gas lasers by runaway-electron beams

It is shown that pumping by runaway-electron beams can be used to arrange lasing in a variety of working media. The output power of a Xe laser vs. beam current is shown for a Xe-He mixture of 1600 Pa with Xe pressure of 20, 70, 300, and 400 Pa, as well as for pure Xe at 360 Pa. The output power vs. Xe pressure is shown for the same Xe-He mixture. Where the upper working level is populated in charge-exchange reactions of singly charged ions, more than 50 percent of the beam energy is expended on producing ions. If the conditions are chosen appropriately, all the ion energy can be transferred to the upper working levels of the active medium in change-exchange reactions. For a helium-mercury laser with an output wavelength of 615 nm, the output energy, output pulse length, and delay of output are shown as a function of the mercury vapor pressure. The efficiency is only 0.016 percent.