High-energy high-current electron beam generation in active media of gas lasers

Abstract

For many technical applications high energy electron beams are required, which are generated in average an high gas pressure, that is, within 10-100 kPa. High pressure gases are the active media of known and promising lasers, characterized by high optical homogeneity, possibility of attainment of high concentration of active elements, existence of laser processes at gas elevated pressures with efficiency up to 50%. The use of relativistic electron beams resulted in the essential power increase of laser generation. However, the drawback to this method is that the electron energy is to be higher than 150-20 keY. The forming of electron high-current beams accelerated up to dozens of keY in gases is described in Refs. 1-4. Electron beams of hundreds keY energy were obtained in the Refs. 5, 6, however, the beam currents were only 1 .0-10.0 A. "Foffless" input of electron beam into an active medium is a major problem which determines the efficiency, the energy and operating characteristics of gas lasers, excited by electron beams. Forming of ' electron beams in the most active medium is one of the promising methods of solving this problem. However, for excitation of gas lasers arid metal-vapor lasers by electron beams obtained in the most active medium, it is necessary to form electron beams of hundreds keY energy and beam current of hundreds and thousands ampere. The same beams, obtained in gases, can be used for excitation of activated crystals lasers and, as well as for a number of technologies. Only few works are devoted to this problem. The electron beams of energy up to 250 keY and beam current up to 2.5kA are obtained experimentally.7 Accelerated electrons appear under the effect of shock waves at high voltage nanosecond leading edge incident on glass tubes. Investigations were carried out in the pressure range 0.1-25.2 kPa. The rapid falloff of electron current is observed at pressure more than 16 kPa. That is why, it is necessary to develop other methods of high energy electrons generation in the range of gas elevated pressures. The present paper gives the results of investigations of forming of high energy electron beams in different gases.